First-principles study of intrinsic defects in formamidinium lead triiodide perovskite solar cell absorbers.

PubMed

Liu, Na; Yam, ChiYung

2018-03-07

As an alternative to methylammonium lead triiodide (MAPbI 3 ), formamidinium lead triiodide (FAPbI 3 ) perovskites have recently attracted significant attention because of their higher stability and smaller band gaps. Here, based on first-principles calculations, we investigate systematically the intrinsic defects in FAPbI 3 . While methylammonium (MA)-related defects MA I and I MA in MAPbI 3 have high formation energies, we found that formamidinium (FA)-related defects V FA , FA I and I FA in FAPbI 3 have much lower formation energies. Antisites FA I and I FA create deep levels in the band gap, and they can act as recombination centers and result in reduced carrier lifetimes and low open circuit voltages in FAPbI 3 -based photovoltaic devices. We further demonstrate that through cation mixing of MA and FA in perovskites the formation of these defects can be substantially suppressed.

Isolation and characterization of Chinese standard fulvic acid sub-fractions separated from forest soil by stepwise elution with pyrophosphate buffer.

PubMed

Bai, Yingchen; Wu, Fengchang; Xing, Baoshan; Meng, Wei; Shi, Guolan; Ma, Yan; Giesy, John P

2015-03-04

XAD-8 adsorption technique coupled with stepwise elution using pyrophosphate buffers with initial pH values of 3, 5, 7, 9, and 13 was developed to isolate Chinese standard fulvic acid (FA) and then separated the FA into five sub-fractions: FApH3, FApH5, FApH7, FApH9 and FApH13, respectively. Mass percentages of FApH3-FApH13 decreased from 42% to 2.5%, and the recovery ratios ranged from 99.0% to 99.5%. Earlier eluting sub-fractions contained greater proportions of carboxylic groups with greater polarity and molecular mass, and later eluting sub-fractions had greater phenolic and aliphatic content. Protein-like components, as well as amorphous and crystalline poly(methylene)-containing components were enriched using neutral and basic buffers. Three main mechanisms likely affect stepwise elution of humic components from XAD-8 resin with pyrophosphate buffers including: 1) the carboxylic-rich sub-fractions are deprotonated at lower pH values and eluted earlier, while phenolic-rich sub-fractions are deprotonated at greater pH values and eluted later. 2) protein or protein-like components can be desorbed and eluted by use of stepwise elution as progressively greater pH values exceed their isoelectric points. 3) size exclusion affects elution of FA sub-fractions. Successful isolation of FA sub-fractions will benefit exploration of the origin, structure, evolution and the investigation of interactions with environmental contaminants.

Isolation and Characterization of Chinese Standard Fulvic Acid Sub-fractions Separated from Forest Soil by Stepwise Elution with Pyrophosphate Buffer

PubMed Central

Bai, Yingchen; Wu, Fengchang; Xing, Baoshan; Meng, Wei; Shi, Guolan; Ma, Yan; Giesy, John P.

2015-01-01

XAD-8 adsorption technique coupled with stepwise elution using pyrophosphate buffers with initial pH values of 3, 5, 7, 9, and 13 was developed to isolate Chinese standard fulvic acid (FA) and then separated the FA into five sub-fractions: FApH3, FApH5, FApH7, FApH9 and FApH13, respectively. Mass percentages of FApH3-FApH13 decreased from 42% to 2.5%, and the recovery ratios ranged from 99.0% to 99.5%. Earlier eluting sub-fractions contained greater proportions of carboxylic groups with greater polarity and molecular mass, and later eluting sub-fractions had greater phenolic and aliphatic content. Protein-like components, as well as amorphous and crystalline poly(methylene)-containing components were enriched using neutral and basic buffers. Three main mechanisms likely affect stepwise elution of humic components from XAD-8 resin with pyrophosphate buffers including: 1) the carboxylic-rich sub-fractions are deprotonated at lower pH values and eluted earlier, while phenolic-rich sub-fractions are deprotonated at greater pH values and eluted later. 2) protein or protein-like components can be desorbed and eluted by use of stepwise elution as progressively greater pH values exceed their isoelectric points. 3) size exclusion affects elution of FA sub-fractions. Successful isolation of FA sub-fractions will benefit exploration of the origin, structure, evolution and the investigation of interactions with environmental contaminants. PMID:25735451

Regulation of Chromatin Assembly and Cell Transformation by Formaldehyde Exposure in Human Cells

PubMed Central

Chen, Danqi; Fang, Lei; Mei, Shenglin; Li, Hongjie; Xu, Xia; Des Marais, Thomas L.; Lu, Kun; Liu, X. Shirley

2017-01-01

Background: Formaldehyde (FA) is an environmental and occupational chemical carcinogen. Recent studies have shown that exogenous FA causes only a modest increase in DNA adduct formation compared with the amount of adducts formed by endogenous FA, raising the possibility that epigenetic mechanisms may contribute to FA-mediated carcinogenicity. Objectives: We investigated the effects of FA exposure on histone modifications and chromatin assembly. We also examined the role of defective chromatin assembly in FA-mediated transcription and cell transformation. Methods: Cellular fractionation and Western blot analysis were used to measure the levels of histone modifications in human bronchial epithelial BEAS-2B cells and human nasal RPMI2650 cells in the presence of FA. Chromatin immunoprecipitation (ChIP) and micrococcal nuclease (MNase) digest assays were performed to examine the changes in chromatin assembly and accessibility after FA exposure. RNA sequencing (RNA-seq) and real-time polymerase chain reaction (PCR) were used to examine transcriptional dysregulation. Finally, anchorage-independent cell growth ability was tested by soft agar assay following FA exposure. Results: Exposure to FA dramatically decreased the acetylation of the N-terminal tails of cytosolic histones. These modifications are important for histone nuclear import and subsequent chromatin assembly. Histone proteins were depleted in both the chromatin fraction and at most of the genomic loci tested following FA exposure, suggesting that FA compromises chromatin assembly. Moreover, FA increased chromatin accessibility and altered the expression of hundreds of cancer-related genes. Knockdown of the histone H3.3 gene (an H3 variant), which mimics inhibition of chromatin assembly, facilitated FA-mediated anchorage-independent cell growth. Conclusions: We propose that the inhibition of chromatin assembly represents a novel mechanism of cell transformation induced by the environmental and occupational chemical carcinogen FA. https://doi.org/10.1289/EHP1275 PMID:28937961

Human Cerebrospinal Fluid Fatty Acid Levels Differ between Supernatant Fluid and Brain-Derived Nanoparticle Fractions, and Are Altered in Alzheimer's Disease

PubMed Central

Fonteh, Alfred N.; Cipolla, Matthew; Chiang, Jiarong; Arakaki, Xianghong; Harrington, Michael G.

2014-01-01

Background Although saturated (SAFA), monounsaturated (MUFA), and polyunsaturated (PUFA) fatty acids are important structural components of neuronal membranes and precursors of signaling molecules, knowledge of their metabolism in Alzheimer's disease (AD) is limited. Based on recent discovery that lipids in cerebrospinal fluid (CSF) are distributed in both brain-derived nanoparticles (NP) and supernatant fluid (SF), we hypothesized that fatty acid (FA) abundance and distribution into these compartments is altered in early AD pathology. Methodology and Findings We assayed the FA composition and abundance in CSF fractions from cognitively healthy (CH), mild cognitive impairment (MCI), and AD study participants using gas chromatography - mass spectrometry. In the SF fraction, concentration of docosahexaenoic acid [DHA, (C22:6n-3)] was less in AD compared with CH, while alpha linolenic acid [α-LNA, (C18:3n-3)] was lower in MCI compared with CH. In the NP fraction, levels of SAFAs (C15:0, C16:0) and a MUFA (C15:1) differentiated CH from MCI, while two MUFAs (C15:1, C19:1) and four PUFAs (C20:2n-6, C20:3n-3, C22:4n-6, C22:5n-3) were higher in AD compared with CH. Levels of even-chain free SAFA and total free FA levels were higher in AD, levels of odd-chain free SAFAs, MUFAs, n-3 PUFAs, and total PUFA, were lower in AD compared with CH. Free n-6 PUFA levels were similar in all three groups. Conclusions and Significance FA metabolism is compartmentalized differently in NP versus SF fractions of CSF, and altered FA levels reflect the importance of abnormal metabolism and oxidative pathways in AD. Depleted DHA in CSF fractions in AD is consistent with the importance of n-3 PUFAs in cognitive function, and suggests that disturbed PUFA metabolism contributes to AD pathology. This study of FA levels in CSF fractions from different cognitive stages shows potential AD biomarkers, and provides further insight into cell membrane dysfunctions, including mechanisms leading to amyloid production. PMID:24956173

Isolation, purification and analysis of dissolved organic carbon from Gohagoda uncontrolled open dumpsite leachate, Sri Lanka.

PubMed

Vithanage, Meththika; Wijesekara, Hasintha; Mayakaduwa, S S

2017-07-01

Extract and analysis of the Dissolved Organic Carbon (DOC) fractions were analyzed from the leachate of an uncontrolled dumpsite at Gohagoda, Sri Lanka. DOC fractions, humic acid (HA), fulvic acid (FA) and the hydrophilic (Hyd) fractions were isolated and purified with the resin techniques. Spectroscopic techniques and elemental analysis were performed to characterize DOCs. Maximum TOC and DOC values recorded were 56,955 and 28,493 mg/L, respectively. Based on the total amount of DOC fractionation, Hyd dominated accounting for ∼60%, and HA and FA constituted ∼22% and ∼17%, respectively, exhibiting the mature phase of the dumpsite. The elemental analysis of DOCs revealed carbon variation following HA > FA > Hyd, while hydrogen and nitrogen were similar in each fraction. The N/C ratio for HA was recorded as 0.18, following a similar trend in old dumpsite leachate elsewhere. The O/C ratios for HA and FA were recorded higher as much as 1.0 and 9.3, respectively, indicating high degree of carbon mineralization in the leachates. High content of carboxylic, phenolic and lactone groups in all DOCs was observed disclosing their potential for toxic substances transportation. The results strongly suggest the risk associated with DOCs in dumpsite leachate to the aquatic and terrestrial environment.

Fatty Acid Proportions in Plasma Cholesterol Esters and Phospholipids Are Positively Correlated in Various Swedish Populations.

PubMed

Marklund, Matti; Pingel, Ronnie; Rosqvist, Fredrik; Lindroos, Anna Karin; Eriksson, Jan W; Vessby, Bengt; Oscarsson, Jan; Lind, Lars; Risérus, Ulf

2017-11-01

Background: Fatty acid (FA) proportions in cholesterol esters (CEs) and plasma phospholipids are widely used as dietary biomarkers. Information on how proportions in these fractions correlate could have implications for interpretation and use of FA biomarkers in observational and interventional studies. Objective: We investigated correlations between FA proportions in CEs and phospholipids in free-living individuals and assessed how diet-induced alterations of FA proportions correlate between fractions. Methods: Spearman's rank correlation coefficients ( r s ) between FA proportions (percentage of total FAs) in circulating CEs and phospholipids were calculated separately in 8 individual study populations including Swedish females and males ( N = 2052; age range: 11-84 y), and pooled by inverse-variance weighted meta-analysis. In addition, study populations were stratified by age, sex, body mass index (BMI; in kg/m 2 ), and diabetes status, and strata-specific r s were pooled by meta-analysis. In 2 randomized trials ( N = 79) in which dietary saturated FAs were isocalorically replaced with unsaturated FAs, treatment-wise calculations of r s were conducted between FA changes in CEs and phospholipids. Results: Overall, FA proportions in CEs and phospholipids correlated well and especially strongly for polyunsaturated FAs (PUFAs), with pooled r s (95% CIs) ranging from 0.74 (0.72, 0.76) for α-linolenic acid to 0.92 (0.91, 0.93) for eicosapentaenoic acid. Weak correlations (pooled r s < 0.4) were observed only for palmitic acid and stearic acid, with pooled r s (95% CIs): 0.29 (0.24, 0.33) and 0.30 (0.25, 0.34), respectively. Overall, correlations were not affected by age, sex, BMI, or diabetes status. Strong correlations ( r s ≥ 0.6) between diet-induced FA changes in CEs and phospholipids were observed for most PUFAs. Conclusions: Proportions of most FAs in CEs and phospholipids ranked individuals similarly, suggesting that FA proportions in these fractions can be used interchangeably in populations of diverse age, sex, body composition, and diabetes status. Caution is advised, however, when comparing results from studies assessing palmitic acid or stearic acid in different lipid fractions. © 2017 American Society for Nutrition.

Evaluation of humic substances removal from leachates originating from solid waste landfills in Rio de Janeiro State, Brazil.

PubMed

Lima, Letícia S M S; De Almeida, Ronei; Quintaes, Bianca R; Bila, Daniele M; Campos, Juacyara C

2017-07-29

This study aimed to evaluate the use of coagulation/flocculation and Fenton processes for the removal of the recalcitrant component, in particular humic substances, from two different leachates generated in the Gericinó and Gramacho landfills in Rio de Janeiro State (Brazil). A coagulation/flocculation process, using FeCl 3 ·6H 2 O as the coagulant, was applied to the two leachate samples. In the case of the leachate from Gericinó landfill, the treatment removed 93% of color, 71% of TOC, 69% of COD, 76% of HS, 73% of humic acids (HA) and 82% of fulvic acids (FA). In addition, there was a 75% reduction in the absorbance at 254 nm, using 3,000 mg L -1 of coagulant. In the case of the leachate from Gramacho landfill, the treatment removed 91% of color, 69% of TOC, 68% of COD, 77% of HS, 75% of HA and 80% of FA. In addition, there was a 70% reduction in the absorbance at 254 nm using the same concentration of coagulant (3,000 mg L -1 ). The Fenton processes, using FeSO 4 ·7H 2 O and H 2 O 2 in a ratio of 1:5, were also applied to the two leachate samples. In the case of the Gericinó leachate, the Fenton treatment removed 95% of color, 75% of TOC, 68% of COD, 82% of HS, 77% of HA and 93% of FA. In addition, there was a 93% reduction in the absorbance at 254 nm. In the case of the Gramacho leachate, the Fenton treatment removed 93% of color, 73% of TOC, 71% of COD, 81% of HS, 76% of HA, 90% of FA, and there was an 84% reduction in the absorbance at 254 nm. The results of humic substances, color, organic matter and aromatic organic matter (absorbance at 254 nm) demonstrate that the coagulation/flocculation and Fenton processes were efficient in the removal of recalcitrant organic matter from landfill leachates.

A new standardized method for quantification of humic and fulvic acids in humic ores and commercial products.

PubMed

Lamar, Richard T; Olk, Daniel C; Mayhew, Lawrence; Bloom, Paul R

2014-01-01

Increased use of humic substances in agriculture has generated intense interest among producers, consumers, and regulators for an accurate and reliable method to quantify humic acid (HA) and fulvic acid (FA) in raw ores and products. Here we present a thoroughly validated method, the new standardized method for determination of HA and FA contents in raw humate ores and in solid and liquid products produced from them. The methods used for preparation of HA and FA were adapted according to the guidelines of the International Humic Substances Society involving alkaline extraction followed by acidification to separate HA from the fulvic fraction. This is followed by separation of FA from the fulvic fraction by adsorption on a nonionic macroporous acrylic ester resin at acid pH. It differs from previous methods in that it determines HA and FA concentrations gravimetrically on an ash-free basis. Critical steps in the method, e.g., initial test portion mass, test portion to extract volume ratio, extraction time, and acidification of alkaline extract, were optimized for maximum and consistent recovery of HA and FA. The method detection limits for HA and FA were 4.62 and 4.8 mg/L, respectively. The method quantitation limits for HA and FA were 14.7 and 15.3 mg/L, respectively.

[Determination of ferulic acid absorbed into human serum from oral decoction of rhizoma chuanxiong and pharmacokinetic study of ferulic acid].

PubMed

Sun, S; Huang, X; Zhang, L; Ren, P; Chang, Z

2001-10-01

To improve the HPLC method for determining ferulic acid(FA) in the human serum and to research FA clinical pharmacokinetics. Serum concentrations of FA were determined by HPLC using methanol-water-acetic acid (40:59.7:0.3, v/v) as the mobile phase and the column packed with ODS (150 mm x 4.6 mm, 5 microns) as a fixed phase and the flow rate was 1.0 ml/min. FA was detected at 320 nm wave length. The internal standard was coumarin. The serum samples were treated by the water-boiling method. Peak of FA in serum was recognized by photodiode-array detection. FA and internal standard were separated completely under the condition described as above. FA was linear in the range of (40.16-8032 ng/ml) (r = 0.9975). The CV was less than 10%, the average recovery was 100.3%, and the limit concentration in serum was 25.1 ng/ml. PK was in accordance with open bicameral model. This method can be applied to clinical pharmacokinetic study of FA.

Effects of intravenous gadolinium administration and flip angle on the assessment of liver fat signal fraction with opposed-phase and in-phase imaging.

PubMed

Yokoo, Takeshi; Collins, Julie M; Hanna, Robert F; Bydder, Mark; Middleton, Michael S; Sirlin, Claude B

2008-07-01

To assess the effects of intravenous gadolinium (Gd) and flip angle (FA) on liver fat quantification by opposed-phase (OP) and in-phase (IP) imaging. Our Institutional Review Board (IRB) approved this Health Insurance Portability and Accountability Act (HIPAA)-compliant, retrospective, clinical study. We identified 79 patients in whom abdominal OP and IP gradient-echoes were obtained at 1.5T before and after Gd administration. All 79 patients were imaged at high FA (> or =70 degrees ); 57 were also imaged at low FA (< or =20 degrees ). Fat signal fraction (FSF) was calculated from pre- and post-Gd liver images for each subject and FA using the formula, FSF = (S(IP) - S(OP))/2S(IP), where S(IP) and S(OP) are the OP and IP signal intensities, respectively. The dataset pairs (pre-Gd vs. post-Gd; high-FA vs. low-FA) were compared using linear regression analysis. Before Gd, FSF was significantly greater at high FA than at low FA, with regression parameters (slope/intercept) of 1.27*/0.02*, where * indicates P value <0.01. After Gd, FSF was similar at high and low FA (0.99/-0.00). Gd administration caused an FA-dependent reduction in FSF, larger at high FA (0.68*/-0.03*) than at low FA (0.94, -0.01*). FSF by OP-IP imaging is highly dependent on FA before Gd, but this dependency is eliminated after administration of Gd. Gd appears to minimize the effect of T1-weighting and may improve the accuracy of liver fat quantification. (c) 2008 Wiley-Liss, Inc.

Lipid Encapsulation Provides Insufficient Total-Tract Digestibility to Achieve an Optimal Transfer Efficiency of Fatty Acids to Milk Fat

PubMed Central

Bainbridge, Melissa; Kraft, Jana

2016-01-01

Transfer efficiencies of rumen-protected n-3 fatty acids (FA) to milk are low, thus we hypothesized that rumen-protection technologies allow for biohydrogenation and excretion of n-3 FA. The objectives of this study were to i) investigate the ruminal protection and post-ruminal release of the FA derived from the lipid-encapsulated echium oil (EEO), and ii) assess the bioavailability and metabolism of the EEO-derived FA through measuring the FA content in plasma lipid fractions, feces, and milk. The EEO was tested for rumen stability using the in situ nylon bag technique, then the apparent total-tract digestibility was assessed in vivo using six Holstein dairy cattle. Diets consisted of a control (no EEO); 1.5% of dry matter (DM) as EEO and 1.5% DM as encapsulation matrix; and 3% DM as EEO. The EEO was rumen-stable and had no effect on animal production. EEO-derived FA were incorporated into all plasma lipid fractions, with the highest proportion of n-3 FA observed in cholesterol esters. Fecal excretion of EEO-derived FA ranged from 7–14%. Biohydrogenation products increased in milk, plasma, and feces with EEO supplementation. In conclusion, lipid-encapsulation provides inadequate digestibility to achieve an optimal transfer efficiency of n-3 FA to milk. PMID:27741299

[Effects of Fulvic Acid on Absorption and Form Distribution of Heavy Metals on Sediments].

PubMed

Li, Yu-qing; He, Jiang; Lü, Chang-wei; Fan, Ming-de; Wang, Wei; Zhang, Rui-qing; Xie, Zhi- lei; Wang, Jing-hua; Yu, Bo; En, He; Ding, Tao

2016-03-15

Based on the extracted fulvic acid (FA) from Lake Wuliangsuhai sediments by sequential alkali extraction, this work studied the effects of FA on the adsorption and fraction distribution of heavy metals (HM) on sediments using original sediments and sediments treated with 30% H₂O₂ as adsorbents. The results showed both organic matter and FA had effects on the HM adsorption onto sediments; The treatments of FA-free conditions and the sediments treated by H₂O₂ showed relatively strong influence on Cu²⁺ adsorption, which decreased the Cu²⁺ adsorption by 17.85%. With the increasing FA addition, the adsorption percentage of HM on both types of sediments showed gradually decreasing trends, with the order of Cu²⁺ > Cd²⁺ > Zn²⁺ > Pb²⁺; when the FA content was more than 5% , FA became the governing factor on the decreasing adsorption percentage of HM. With increasing FA addition, forms distribution of HM showed significant changes in both types of sediments; i. e. FA additions showed significant negative and positive correlations with percentages of metals bound to carbonates and organic matter, respectively, since the FA addition increased the H⁺ concentration of the system, in which H⁺ could activate the metals bound to carbonate from the sediments. As an organophilic weak element, the fraction percentage of Cd bound to organic matter was the lowest with the minimal changes.

Selenium fractions in organic matter from Se-rich soils and weathered stone coal in selenosis areas of China.

PubMed

Qin, Hai-bo; Zhu, Jian-ming; Su, Hui

2012-02-01

A high degree of association between Selenium (Se) and organic matter has been demonstrated in natural environments, but Se fractions and speciation in organic matter is unclear. In this study, a method for quantifying organic matter associated with Se (OM-Se) was developed to investigate Se fractions in organic matter in Se-rich soils and weathered stone coal from Enshi, China, where Se poisoning of humans and livestock has been documented. Initially, Se was extracted using water and a phosphate buffer. Subsequently, OM-Se was extracted using NaOH, and then speciated into Se associated with fulvic acids (FA-Se) and humic acids (HA-Se). Both FA-Se and HA-Se were further speciated into the weakly bound and strongly bound fractions using a customized hydride generation reactor. The results show that FA-Se (1.91-479 mg kg(-1)) is the predominant form of Se in all Se-rich soils and the weathered stone coal samples, accounting for more than 62% of OM-Se (3.07-484 mg kg(-1)). Weakly bound FA-Se (1.33-450 mg kg(-1)) was prevalent in the total FA-Se, while weakly bound HA-Se (0.62-26.2 mg kg(-1)) was variable in the total HA-Se (1.15-32.5 mg kg(-1)). These data indicate that OM-Se could play a significant source and sink role in the biogeochemical cycling of Se in the supergene environment. Weakly bound FA-Se seems to act as a potential source for bioavailable Se, whereas strongly bound HA-Se is a possible OM-Se sink which is not readily transformed into bioavailable Se. Copyright © 2011 Elsevier Ltd. All rights reserved.

Assessment of chemical and biochemical stabilization of organic C in soils from the long-term experiments at Rothamsted (UK).

PubMed

De Nobili, M; Contin, M; Mahieu, N; Randall, E W; Brookes, P C

2008-01-01

Biological and chemical stabilization of organic C was assessed in soils sampled from the long-term experiments at Rothamsted (UK), representing a wide range of carbon inputs and managements by extracting labile, non-humified organic matter (NH) and humic substances (HS). Four sequentially extracted humic substances fractions of soil organic matter (SOM) were extracted and characterized before and after a 215-day laboratory incubation at 25 degrees C from two arable soils, a woodland soil and an occasionally stubbed soil. The fractions corresponded to biochemically stabilised SOM extracted in 0.5M NaOH (free fulvic acids (FA) and humic acids (HA)) and chemically plus biochemically stabilised SOM extracted from the residue with 0.1M Na4P2O7 plus 0.1M NaOH (bound FA and HA). Our aim was to investigate the effects of chemical and biochemical stabilization on carbon sequestration. The non-humic to humic (NH/H) C ratio separated the soils into two distinct groups: arable soils (unless fertilised with farmyard manure) had an NH/H C ratio between 1.05 and 0.71, about twice that of the other soils (0.51-0.26). During incubation a slow, but detectable, decrease in the NH/H C ratio occurred in soils of C input equivalent or lower to 4Mgha(-1)y(-1), whereas the ratio remained practically constant in the other soils. Before incubation the free to bound humic C ratio increased linearly (R2=0.91) with C inputs in the soils from the Broadbalk experiment and decreased during incubation, showing that biochemical stabilization is less effective than chemical stabilization in preserving humic C. Changes in delta13C and delta15N after incubation were confined to the free FA fractions. The delta13C of free FA increased by 1.48 and 0.80 per thousand, respectively, in the stubbed and woodland soils, indicating a progressive biological transformation. On the contrary, a decrease was observed for the bound FA of both soils. Concomitantly, a Deltadelta15N of up to +3.52 per thousand was measured after incubation in the free FA fraction and a -2.58 Deltadelta15N in the bound FA. These changes, which occurred during soil incubation in the absence of C inputs, indicate that free FA fractions were utilised by soil microorganisms, and bound FA were decomposed and replaced, in part, by newly synthesized FA. The 13CPMAS-TOSS NMR spectra of free HA extracted before and after 215 days of incubation were mostly unchanged. In contrast, changes were evident in bound HA and showed an increase in aromatic C after incubation.

Measurement of the alpha4beta2* nicotinic acetylcholine receptor ligand 2-[(18)F]Fluoro-A-85380 and its metabolites in human blood during PET investigation: a methodological study.

PubMed

Sorger, Dietlind; Becker, Georg A; Patt, Marianne; Schildan, Andreas; Grossmann, Udo; Schliebs, Reinhard; Seese, Anita; Kendziorra, Kai; Kluge, Magnus; Brust, Peter; Mukhin, Alexey G; Sabri, Osama

2007-04-01

2-[(18)F]fluoro-A-85380 (2-[(18)F]FA) is a new radioligand for noninvasive imaging of alpha4beta2* nicotinic acetylcholine receptors (nAChRs) by positron emission tomography (PET) in human brain. In most cases, quantification of 2-[(18)F]FA receptor binding involves measurement of free nonmetabolized radioligand concentration in blood. This requires an efficient and reliable method to separate radioactive metabolites from the parent compound. In the present study, three analytical methods, thin layer chromatography (TLC), high-performance liquid chromatography (HPLC) and solid phase extraction (SPE) have been tested. Reversed-phase TLC of deproteinized aqueous samples of plasma provides good estimates of 2-[(18)F]FA and its metabolites. However, because of the decreased radioactivity in plasma samples, this method can be used in humans over the first 2 h after radioligand injection only. Reliable quantification of the parent radioligand and its main metabolites was obtained using reversed-phase HPLC, followed by counting of eluted fractions in a well gamma counter. Three main and five minor metabolites of 2-[(18)F]FA were detected in human blood using this method. On average, the unchanged 2-[(18)F]FA fraction in plasma of healthy volunteers measured at 14, 60, 120, 240 and 420 min after radioligand injection was 87.3+/-2.2%, 74.4+/-3%, 68.8+/-5%, 62.3+/-8% and 61.0+/-8%, respectively. In patients with neurodegenerative disorders, the values corresponding to the three last time points were significantly lower. The fraction of nonmetabolized 2-[(18)F]FA in plasma determined using SPE did not differ significantly from that obtained by HPLC (+gamma counting) (n=73, r=.95). Since SPE is less time-consuming than HPLC and provides comparable results, we conclude that SPE appears to be the most suitable method for measurement of 2-[(18)F]FA parent fraction during PET investigations.

Systematic Analysis of Main Constituents in Rat Biological Samples after Oral Administration of the Methanol Extract of Fructus Aurantii by HPLC-ESI-MS/MS.

PubMed

Zhang, Jingze; Gao, Wenyuan; Liu, Zhen; Zhang, Zhidan; Liu, Changxiao

2014-01-01

High performance liquid chromatography (HPLC) with diode array detection (DAD) and electrospray ionization tandem mass spectrometry (ESI/MS/MS) was used to analyze the main components in the methanol extract of Fructus Aurantii (FA) and the metabolites in rat biological samples after oral administration of the methanol extract of FA. There were 31 constituents identified in the extract of FA including 2 alkaloids, 1 coumarin, 10 flavonoid glycosides and 18 ploymethoxylated flavones. According to the UV spectrum and MS fragment character of main components in the methanol extract of FA, 18 parent constituents and 11 metabolites were tentatively identified in rat biological samples. Three groups of components in biological samples detected included flavonoid glycosides, their glucuronides and ploymethoxylated flavones. It was interested that flavonoid glycosides, their glucuronides and ploymethoxylated flavones can be investigated in rat plasma and urine, while in rat feces samples only flavonoid glycosides were detected. Triglycosyl, naringenin, neoeriocitrin, neoeriocitrin narirutin and hesperidin were the main components in rat feces which were found either in the plasma or in urine samples. However, naringin and neohesperidin were the main flavonoid glycosides which absorbed after oral administration. Except flavonoid glycosides and their glucuronides, ploymethoxylated flavones also the constituents absorbed because it was investigated mainly in rat plasma and urine but not in feces samples. The identification and elucidation of parent and metabolism components analyzed in biological samples provided the data for further pharmacological and clinical research on FA.

Diffusion anisotropy in fresh and fixed prostate tissue ex vivo.

PubMed

Bourne, Roger M; Bongers, Andre; Chatterjee, Aritrick; Sved, Paul; Watson, Geoffrey

2016-08-01

To investigate diffusion anisotropy in whole human prostate specimens Seven whole radical prostatectomy specimens were obtained with informed patient consent and institutional ethics approval. Diffusion tensor imaging was performed at 9.4 Tesla. Diffusion tensors were calculated from the native acquired data and after progressive downsampling Fractional anisotropy (FA) decreased as voxel volume increased, and differed widely between prostates. Fixation decreased mean FA by ∼0.05-0.08 at all voxel volumes but did not alter principle eigenvector orientation. In unfixed tissue high FA (> 0.6) was found only in voxels of volume <0.5 mm(3) , and then only in a small fraction of all voxels. At typical clinical voxel volumes (4-16 mm(3) ) less than 50% of voxels had FA > 0.25. FA decreased at longer diffusion times (Δ = 60 or 80 ms compared with 20 ms), but only by ∼0.02 at typical clinical voxel volume. Peripheral zone FA was significantly lower than transition zone FA in five of the seven prostates FA varies widely between prostates. The very small proportion of clinical size voxels with high FA suggests that in clinical DWI studies ADC based on three-direction measurements will be minimally affected by anisotropy. Magn Reson Med 76:626-634, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Tract-specific fractional anisotropy predicts cognitive outcome in a community sample of middle-aged participants with white matter lesions

PubMed Central

Soriano-Raya, Juan José; Miralbell, Júlia; López-Cancio, Elena; Bargalló, Núria; Arenillas, Juan Francisco; Barrios, Maite; Cáceres, Cynthia; Toran, Pere; Alzamora, Maite; Dávalos, Antoni; Mataró, Maria

2014-01-01

Cerebral white matter lesions (WMLs) have been consistently related to cognitive dysfunction but the role of white matter (WM) damage in cognitive impairment is not fully determined. Diffusion tensor imaging is a promising tool to explain impaired cognition related to WMLs. We investigated the separate association of high-grade periventricular hyperintensities (PVHs) and deep white matter hyperintensities (DWMHs) with fractional anisotropy (FA) in middle-aged individuals. We also assessed the predictive value to cognition of FA within specific WM tracts associated with high-grade WMLs. One hundred participants from the Barcelona-AsIA Neuropsychology Study were divided into groups based on low- and high-grade WMLs. Voxel-by-voxel FA were compared between groups, with separate analyses for high-grade PVHs and DWMHs. The mean FA within areas showing differences between groups was extracted in each tract for linear regression analyses. Participants with high-grade PVHs and participants with high-grade DWMHs showed lower FA in different areas of specific tracts. Areas showing decreased FA in high-grade DWMHs predicted lower cognition, whereas areas with decreased FA in high-grade PVHs did not. The predictive value to cognition of specific WM tracts supports the involvement of cortico-subcortical circuits in cognitive deficits only in DWMHs. PMID:24549185

Tract-specific fractional anisotropy predicts cognitive outcome in a community sample of middle-aged participants with white matter lesions.

PubMed

Soriano-Raya, Juan José; Miralbell, Júlia; López-Cancio, Elena; Bargalló, Núria; Arenillas, Juan Francisco; Barrios, Maite; Cáceres, Cynthia; Toran, Pere; Alzamora, Maite; Dávalos, Antoni; Mataró, Maria

2014-05-01

Cerebral white matter lesions (WMLs) have been consistently related to cognitive dysfunction but the role of white matter (WM) damage in cognitive impairment is not fully determined. Diffusion tensor imaging is a promising tool to explain impaired cognition related to WMLs. We investigated the separate association of high-grade periventricular hyperintensities (PVHs) and deep white matter hyperintensities (DWMHs) with fractional anisotropy (FA) in middle-aged individuals. We also assessed the predictive value to cognition of FA within specific WM tracts associated with high-grade WMLs. One hundred participants from the Barcelona-AsIA Neuropsychology Study were divided into groups based on low- and high-grade WMLs. Voxel-by-voxel FA were compared between groups, with separate analyses for high-grade PVHs and DWMHs. The mean FA within areas showing differences between groups was extracted in each tract for linear regression analyses. Participants with high-grade PVHs and participants with high-grade DWMHs showed lower FA in different areas of specific tracts. Areas showing decreased FA in high-grade DWMHs predicted lower cognition, whereas areas with decreased FA in high-grade PVHs did not. The predictive value to cognition of specific WM tracts supports the involvement of cortico-subcortical circuits in cognitive deficits only in DWMHs.

Diffusion-Tensor Imaging of Thigh Muscles in Duchenne Muscular Dystrophy: Correlation of Apparent Diffusion Coefficient and Fractional Anisotropy Values With Fatty Infiltration.

PubMed

Li, Gui Dian; Liang, Ying Yin; Xu, Ping; Ling, Jian; Chen, Ying Ming

2016-04-01

The purpose of this study is to investigate the correlation of apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values with fatty infiltration in the thigh muscles of patients with Duchenne muscular dystrophy (DMD) using diffusion-tensor imaging (DTI). Twenty-one boys with DMD were recruited. The grade of fatty infiltration and the ADC and FA values of four thigh muscles (rectus femoris, semitendinosus, sartorius, and gracilis) were measured, and the FA and ADC values were compared with the grade of fatty infiltration. Twenty age-matched healthy boys were enrolled as the control group. The differences in the ADC and FA values of the thigh muscles between patients with DMD and the control group were compared. The patients with DMD showed lower FA values and higher ADC values in all measured muscles when compared with the control group. The FA and ADC values were correlated with the grade of fatty infiltration. For the rectus femoris muscle, r = -0.753 and p = 0.007 for FA, and r = 0.685 and p = 0.001 for ADC. For the semitendinosus muscle, r = -0.621 and p = 0.041 for FA, and r = 0.705 and p = 0.021 for ADC. For the sartorius muscle, r = -0.662 and p = 0.027 for FA, and r = 0.701 and p = 0.017 for ADC. For the gracilis muscle, r = -0.618 and p = 0.043 for FA, and r = 0.695 and p = 0.022 for ADC. Damage to the thigh muscles in patients with DMD can be detected by ADC and FA values using DTI. DTI can be used to assess the severity of the disease.

Comparing the performance of FA, DFA and DMA using different synthetic long-range correlated time series

PubMed Central

Shao, Ying-Hui; Gu, Gao-Feng; Jiang, Zhi-Qiang; Zhou, Wei-Xing; Sornette, Didier

2012-01-01

Notwithstanding the significant efforts to develop estimators of long-range correlations (LRC) and to compare their performance, no clear consensus exists on what is the best method and under which conditions. In addition, synthetic tests suggest that the performance of LRC estimators varies when using different generators of LRC time series. Here, we compare the performances of four estimators [Fluctuation Analysis (FA), Detrended Fluctuation Analysis (DFA), Backward Detrending Moving Average (BDMA), and Centred Detrending Moving Average (CDMA)]. We use three different generators [Fractional Gaussian Noises, and two ways of generating Fractional Brownian Motions]. We find that CDMA has the best performance and DFA is only slightly worse in some situations, while FA performs the worst. In addition, CDMA and DFA are less sensitive to the scaling range than FA. Hence, CDMA and DFA remain “The Methods of Choice” in determining the Hurst index of time series. PMID:23150785

Evaluation of monitoring indicators for the post-closure care of a landfill for MSW characterized with low lignin content.

PubMed

Zheng, Wei; Lü, Fan; Bolyard, Stephanie C; Shao, Liming; Reinhart, Debra R; He, Pinjing

2015-02-01

To understand the applicability of the termination indicators for landfill municipal solid waste (MSW) with low initial lignin content, four different accelerated landfill stabilization techniques were applied to anaerobic landfilled waste, including anaerobic flushing with water, anaerobic flushing with Fenton-treated leachate, and aerobic flushing with Fenton-treated and UV/H2O2-treated leachate. Termination indicators, including total organic carbon (TOC), ammonia-N (NH4(+)-N), the ratio of UV absorbance at 254 nm to TOC concentration (SUVA254), fluorescence spectra of leachate, methane production, oxygen consumption, lignocellulose content, and humus-like content were evaluated. Results suggest that oxygen consumption related indicators used as a termination indicator for low-lignin-content MSW were more sensitive than methane consumption related indicators. Aeration increased humic acid (HA) and (HA+FA)/HyI content by 2.9 and 1.7 times compared to the anaerobically stabilized low-lignin-content MSW. On the other hand, both the fulvic acid (FA) and hydrophilic (HyI) fractions remained constant regardless of stabilization technique. The target value developed for low-lignin-content MSW was quite different than developed countries mainly due to low residual biodegradable organic carbon content in stabilized low-lignin-content MSW. Copyright © 2014 Elsevier Ltd. All rights reserved.

Individual white matter fractional anisotropy analysis on patients with MRI negative partial epilepsy.

PubMed

Duning, Thomas; Kellinghaus, Christoph; Mohammadi, Siawoosh; Schiffbauer, Hagen; Keller, Simon; Ringelstein, E Bernd; Knecht, Stefan; Deppe, Michael

2010-02-01

Conventional structural MRI fails to identify a cerebral lesion in 25% of patients with cryptogenic partial epilepsy (CPE). Diffusion tensor imaging is an MRI technique sensitive to microstructural abnormalities of cerebral white matter (WM) by quantification of fractional anisotropy (FA). The objectives of the present study were to identify focal FA abnormalities in patients with CPE who were deemed MRI negative during routine presurgical evaluation. Diffusion tensor imaging at 3 T was performed in 12 patients with CPE and normal conventional MRI and in 67 age matched healthy volunteers. WM integrity was compared between groups on the basis of automated voxel-wise statistics of FA maps using an analysis of covariance. Volumetric measurements from high resolution T1-weighted images were also performed. Significant FA reductions in WM regions encompassing diffuse areas of the brain were observed when all patients as a group were compared with controls. On an individual basis, voxel based analyses revealed widespread symmetrical FA reduction in CPE patients. Furthermore, asymmetrical temporal lobe FA reduction was consistently ipsilateral to the electroclinical focus. No significant correlations were found between FA alterations and clinical data. There were no differences in brain volumes of CPE patients compared with controls. Despite normal conventional MRI, WM integrity abnormalities in CPE patients extend far beyond the epileptogenic zone. Given that unilateral temporal lobe FA abnormalities were consistently observed ipsilateral to the seizure focus, analysis of temporal FA may provide an informative in vivo investigation into the localisation of the epileptogenic zone in MRI negative patients.

Pre-operative declining proportion of fractional anisotropy of trigeminal nerve is correlated with the outcome of micro-vascular decompression surgery.

PubMed

Chen, Fanfan; Chen, Lei; Li, Wei; Li, Ling; Xu, Xiangdong; Li, Weimin; Le, Wuhua; Xie, Wei; He, Hua; Li, Peng

2016-07-16

Type 2 trigeminal neuralgia (TN) is an intractable neuropathic pain syndrome compared with type 1 TN because of the difficulty of diagnosis as well as the unsatisfactory prognosis. Neurovascular compression (NVC) is considered the major pathology of TN. Routine magnetic resonance imaging (MRI) sequences are inadequate for revealing the effect of NVC which is related to the surgical decision and outcome. The decreasing of fractional anisotropy (FA), one of the MRI diffusion tensor imaging (DTI) metrics, is correlated with the demyelination of trigeminal nerve (TGN) that reveal the severity of NVC. A retrospective review of patients treated with micro-vascular decompression (MVD) surgery was undertaken. All the patients were diagnosed as type 2 TN. FA of TGN of both sides were measured. The FA declining proportion = ((the mean FA value of healthy lateral)-(the mean FA value of the symptomatic lateral))/(the mean FA value of healthy lateral). Declining proportion of FA value, discovery of surgery and outcome of MVD were recorded and analyzed. Logistic regression analysis and linear regression analysis were employed to analyze the risk factors of declining proportion of FA value and MVD outcome. Nineteen patients were assessed in our study. The average declining proportion of FA value for all patients was 0.25 ± 0.12. The average declining proportion of FA value of "success" and "failure" group was 0.32 ± 0.09 to 0.14 ± 0.10 (P = 0.002 < 0.05). The declining proportion of FA value of artery (including the artery plus vein situation) was 0.34 ± 0.06 in contrast to 0.15 ± 0.08 of vein (P = 0.000 < 0.05). MVD outcome was correlated with declining proportion of FA value (AUC = 0.900). Furthermore, declining proportion of FA value was higher in arterial compression situation. FA value quantitatively showed the alteration of TGN caused by NVC. It provided direct evidence about the effect of NVC which facilitated the diagnosis and surgical decision of type 2 TN. Besides, significant reduction of FA value may predict an optimistic outcome of MVD.

Identification of furan fatty acids in the lipids of common carp (Cyprinus carpio L.).

PubMed

Chvalová, Daniela; Špička, Jiří

2016-06-01

Fatty acid (FA) composition was analyzed in muscle and gonad tissues of marketed common carp (Cyprinus carpio). The extracted lipids were separated into four fractions: polar lipids (PL), diacylglycerols, free fatty acids and triacylglycerols (TAG) using thin layer chromatography. FA content within the lipid fractions was determined by gas chromatography with flame ionization detector (GC/FID). The muscle lipids consisted primarily of TAG (96.9% of total FA), while PL were the major component of both male (67.6%) and female gonad (58.6%) lipids. Polyunsaturated fatty acids predominated in PL of all tissues (52.2-55.8% of total FA); monounsaturated fatty acids were the most abundant FA group in TAG of muscle (51.8%) and female gonads (47.8%) whereas high proportion of furan fatty acids (F-acids) (38.2%) was detected in TAG of male gonads. Eight F-acids were identified by gas chromatography-mass spectrometry (GC/MS) in male gonad samples, including less common 12,15-epoxy-13,14-dimethylnonadeca-12,14-dienoic acid with even-numbered alkyl moiety. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of flavonoid glycosides obtained from a Ginkgo biloba extract fraction on the physical and oxidative stabilities of oil-in-water emulsions prepared from a stripped structured lipid with a low omega-6 to omega-3 ratio.

PubMed

Yang, Dan; Wang, Xiang-Yu; Gan, Lu-Jing; Zhang, Hua; Shin, Jung-Ah; Lee, Ki-Teak; Hong, Soon-Taek

2015-05-01

In this study, we have produced a structured lipid with a low ω6/ω3 ratio by lipase-catalysed interesterification with perilla and grape seed oils (1:3, wt/wt). A Ginkgo biloba leaf extract was fractionated in a column packed with HP-20 resin, producing a flavonoid glycoside fraction (FA) and a biflavone fraction (FB). FA exhibited higher antioxidant capacity than FB, showing 58.4 mmol gallic acid equivalent (GAE)/g-of-total-phenol-content, 58.8 mg quercetin equivalent (QUE)/g-of-total-flavonoid-content, 4.5 mmol trolox/g-of-trolox-equivalent antioxidant capacity, 0.14 mg extract/mL-of-free-radical-scavenging-activity (DPPH assay, IC50), and 2.3 mmol Fe2SO4 · 7H2O/g-of-ferric-reducing-antioxidant-power. The oil-in-water emulsion containing the stripped structured lipid as an oil phase with FA exhibited the highest stability and the lowest oil globule diameters (d43 and d32), where the aggregation was unnoticeable by Turbiscan and particle size analyses during 30 days of storage. Furthermore, FA was effective in retarding the oxidation of the emulsions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Analytical functions for beta and gamma absorbed fractions of iodine-131 in spherical and ellipsoidal volumes.

PubMed

Mowlavi, Ali Asghar; Fornasier, Maria Rossa; Mirzaei, Mohammd; Bregant, Paola; de Denaro, Mario

2014-10-01

The beta and gamma absorbed fractions in organs and tissues are the important key factors of radionuclide internal dosimetry based on Medical Internal Radiation Dose (MIRD) approach. The aim of this study is to find suitable analytical functions for beta and gamma absorbed fractions in spherical and ellipsoidal volumes with a uniform distribution of iodine-131 radionuclide. MCNPX code has been used to calculate the energy absorption from beta and gamma rays of iodine-131 uniformly distributed inside different ellipsoids and spheres, and then the absorbed fractions have been evaluated. We have found the fit parameters of a suitable analytical function for the beta absorbed fraction, depending on a generalized radius for ellipsoid based on the radius of sphere, and a linear fit function for the gamma absorbed fraction. The analytical functions that we obtained from fitting process in Monte Carlo data can be used for obtaining the absorbed fractions of iodine-131 beta and gamma rays for any volume of the thyroid lobe. Moreover, our results for the spheres are in good agreement with the results of MIRD and other scientific literatures.

Synthesis and properties of feruloyl corn bran arabinoxylan esters.

PubMed

Li, Y; Yang, C

2016-06-01

To enhance the antioxidant activity and UV absorption coefficient of corn bran arabinoxylan (CAX), ferulic acid (FA) with this physiological activity is used to modify CAX. Corn bran arabinoxylan was extracted from corn bran according to alkaline hydrogen peroxide (AHP) method. FA was covalently linked to CAX by esterification in a two-step feasible synthesis to generate ferulic acid arabinoxylan esters (FA-CAX). The structure and molecular weight of FA-CAX were characterized by NMR and HPSEC, the degrees of substitution (DS) was determined by HPLC, and the ultraviolet (UV) coefficient of FA-CAX was tested by UV spectroscopy. The antioxidant activity of FA-CAX was investigated on the basis of 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical assay, and protecting ability of FA-CAX to UV-induced oxidative damage was tested using linolenic acid dispersion as stratum corneum lipid model. The results demonstrated that FA was attached to CAX successfully, and the inherent structure of CAX would not be broken during the process of the synthesis. FA-CAX-1 and FA-CAX-2 contained different amount of FA, with DS at 0.33 and 1.25, respectively, can absorb UV both at UVA and UVB. Moreover, FA-CAX-2 exhibited better antioxidant activity than FA-CAX-1 based on the two test methods. Ferulic acid modified CAX had significant antioxidant ability and UV absorption coefficient. And higher amount of FA leads to higher antioxidant activity and stronger UV absorption and stability. With increasing amount of FA attached to CAX, the antioxidant activities were better and the UV absorption was stronger and more durable. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Chemistry and potential mutagenicity of humic substances in waters from different watersheds in Britain and Ireland

USGS Publications Warehouse

Watt, B.E.; Malcolm, R.L.; Hayes, M.H.B.; Clark, N.W.E.; Chipman, J.K.

1996-01-01

Humic substances are amorphous organic macromolecules responsible for the hue of natural waters. They are also known to be precursors of mutagens formed on chlorination prior to distribution of drinking water. In this study humic substances from the waters of primary streams, from major rivers, and from reservoirs were isolated and fractionated into humic acids (HA), fulvic acids (FA) and XAD-4 acids using columns of XAD-8 and of XAD-4 resins in tandem, and the fractions from the different sources were chlorinated and assayed for mutagenicity. CPMAS 13C NMR spectroscopy showed marked differences in compositions not only between HA, FA, and XAD-4 acids from the same water samples, but also between the same fractions from water samples from different watersheds. There were found to be strong similarities between the fractions from watersheds which had closely related soil types. Aromaticity was greatest in HAs, and lowest in XAD-4 acids, and carboxyl contents and aliphatic character were greatest in the XAD-4 acids. Carbon content decreased in the order HA > FA > XAD-4 acids, and amino acids and neutral sugars contents decreased in the order HA > XAD-4 > FA. Titration data complemented aspects of the NMR data, demonstrating that carboxyl content decreased in the order XAD-4 acids > FA > HA, and indicated that phenolic character was highest in HAs and lowest in the XAD-4 acids. All samples tested gave rise to bacterial mutagens on chlorination. Although the mutagenicities were of the same order of magnitude for the chlorinated humic samples from the different sources, the samples which showed the greatest number of revertant bacterial colonies were from the Thames and Trent, large rivers with humic materials from diverse environments, and relatively high in amino acid contents.

[Characterization of soil humus by FTIR spectroscopic analyses after being inoculated with different microorganisms plus wheat straw].

PubMed

Wang, Shuail; Dou, Sen; Liu, Yan-Li; Li, Hui-Min; Cui, Jun-Tao; Zhang, Wei; Wang, Cheng-Yu

2012-09-01

The effects of different microbial communities on the structural characteristics of humus from the black soil amended with wheat straw were studied by FTIR Spectroscopy. The results indicated that (1) The structure and amount of functional groups in the water soluble substances (WSS) was tremendously influenced by the tested microorganisms, of which the amino and aryl ether was degraded rapidly in the inoculation process, and in the meantime, the content of hydroxyl groups was significantly reduced. The bacteria was helpful to increasing the amount of aliphatic hydrocarbons, while the other inoculated treatments were contrary. At the end of culture, the phenols and polysaccharides were gradually consumed, but the content of carboxyl groups had an increasing trend. (2) In the aspect of reducing hydroxyl groups of fulvic acid (FA), the role of actinomycetes was the biggest. The fungi had the biggest effect in improving the net generation of FA content. In addition, the fungi was conducive to improve the contents of carboxyl groups and carbohydrates of FA fraction. Except the mixed strains, the other treatments were all beneficial to the degradation of polysaccharide in the FA fraction, whose rate was greater than the decomposition of lipids. (3) The bacteria, actinomycetes and fungi were all helpful to reducing the amount of aliphatic hydrocarbons of HA fraction except the mixed strains. The content of carboxyl was effectively increased by fungi, but the effect of bacteria was contrary. The tested microorganisms could consume and utilize the polysaccharides of HA fraction, which could transform the humic-like fractions from plant residues into the real humus of soil.

Reproducibility, interrater agreement, and age-related changes of fractional anisotropy measures at 3T in healthy subjects: effect of the applied b-value.

PubMed

Bisdas, S; Bohning, D E; Besenski, N; Nicholas, J S; Rumboldt, Z

2008-06-01

There is no reproducibility study of fractional anisotropy (FA) measurements at 3T using regions of interest (ROIs). Our purpose was to establish the extent and statistical significance of the interrater variability, the variability observed with 2 different b-values, and in 2 separate scanning sessions. Twelve healthy volunteers underwent MR imaging twice. MR imaging was performed on a 3T unit, and FA maps were analyzed independently by 2 observers using ROIs positioned in the corpus callosum, internal capsules, corticospinal tracts, and right thalamus. Changes in FA values (x10(3)) measured with 2 b-values (700 and 1000 s/mm(2)), age-related differences, interobserver agreement, and measurement reproducibility were assessed. In the right internal capsule genu (FA = 702/728; b = 1000/700 s/mm(2)) and the left anterior limb of the internal capsule (AIC; FA = 617/745; b = 1000/700 s/mm(2)), the FA values were significantly different between the 2 b-values (P = .02 and .05, respectively). Significant age-related differences in FA were observed in the genu of the corpus callosum and in the left AIC. Interrater measurements showed fair-to-moderate agreement for most anatomic structures. The lowest significant change for a single subject regarding any FA values between the 2 sessions was in the corpus callosum (4%), whereas the highest one was in the corticospinal tracts (27%). The Bland-Altman plot analysis showed that the 1000-s/mm(2) b-value gave satisfactorily reproducible measurements equally good or better than the 700-s/mm(2) b-value. The reproducibility of FA estimates using ROIs was satisfactory. Measurements with a b-value at 1000 s/mm(2) showed superior reproducibility in most anatomic locations.

Relationship between diffusion tensor fractional anisotropy and motor outcome in patients with hemiparesis after corona radiata infarct.

PubMed

Koyama, Tetsuo; Marumoto, Kohei; Miyake, Hiroji; Domen, Kazuhisa

2013-11-01

This study examined the relationship between fractional anisotropy (FA) values of magnetic resonance-diffusion tensor imaging (DTI) and motor outcome (1 month after onset) in 15 patients with hemiparesis after ischemic stroke of corona radiata lesions. DTI data were obtained on days 14-18. FA values within the cerebral peduncle were analyzed using a computer-automated method. Motor outcome of hemiparesis was evaluated according to Brunnstrom stage (BRS; 6-point scale: severe to normal) for separate shoulder/elbow/forearm, wrist/hand, and lower extremity functions. The ratio of FA values in the affected hemisphere to those in the unaffected hemisphere (rFA) was assessed in relation to the BRS data (Spearman rank correlation test, P<.05). rFA values ranged from .715 to 1.002 (median=.924). BRS ranged from 1 to 6 (median=4) for shoulder/elbow/forearm, from 1 to 6 (median=5) for wrist/hand, and from 2 to 6 (median=4) for the lower extremities. Analysis revealed statistically significant relationships between rFA and upper extremity functions (correlation coefficient=.679 for shoulder/elbow/forearm and .706 for wrist/hand). Although slightly less evident, the relationship between rFA and lower extremity function was also statistically significant (correlation coefficient=.641). FA values within the cerebral peduncle are moderately associated with the outcome of both upper and lower extremity functions, suggesting that DTI may be applicable for outcome prediction in stroke patients with corona radiata infarct. Copyright © 2013 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Spectral characterization of the fluorescent components present in humic substances, fulvic acid and humic acid mixed with pure benzo(a)pyrene solution.

PubMed

El Fallah, Rawa; Rouillon, Régis; Vouvé, Florence

2018-06-15

The fate of benzo(a)pyrene (BaP), a ubiquitous contaminant reported to be persistent in the environment, is largely controlled by its interactions with the soil organic matter. In the present study, the spectral characteristics of fluorophores present in the physical fractions of the soil organic matter were investigated in the presence of pure BaP solution. After extraction of humic substances (HSs), and their fractionation into fluvic acid (FA) and humic acid (HA), two fluorescent compounds (C 1 and C 2 ) were identified and characterized in each physical soil fraction, by means of fluorescence excitation-emission matrices (FEEMs) and Parallel Factor Analysis (PARAFAC). Then, to each type of fraction having similar DOC content, was added an increasing volume of pure BaP solution in attempt to assess the behavior of BaP with the fluorophores present in each one. The application of FEEMs-PARAFAC method validated a three-component model that consisted of the two resulted fluorophores from HSs, FA and HA (C 1 and C 2 ) and a BaP-like fluorophore (C 3 ). Spectral modifications were noted for components C 2 HSs (C 2 in humic substances fraction) (λex/λem: 420/490-520 nm), C 2 FA (C 2 in fulvic acid fraction) (λex/λem: 400/487(517) nm) and C 1 HA (C 1 in humic acid fraction) (λex/λem: 350/452(520) nm). We explored the impact of increasing the volume of the added pure BaP solution on the scores of the fluorophores present in the soil fractions. It was found that the scores of C 2 HSs, C 2 FA, and C 1 HA increased when the volume of the added pure BaP solution increased. Superposition of the excitation spectra of these fluorophores with the emission spectrum of BaP showed significant overlaps that might explain the observed interactions between BaP and the fluorescent compounds present in SOM physical fractions. Copyright © 2018 Elsevier B.V. All rights reserved.

Spectral characterization of the fluorescent components present in humic substances, fulvic acid and humic acid mixed with pure benzo(a)pyrene solution

NASA Astrophysics Data System (ADS)

El Fallah, Rawa; Rouillon, Régis; Vouvé, Florence

2018-06-01

The fate of benzo(a)pyrene (BaP), a ubiquitous contaminant reported to be persistent in the environment, is largely controlled by its interactions with the soil organic matter. In the present study, the spectral characteristics of fluorophores present in the physical fractions of the soil organic matter were investigated in the presence of pure BaP solution. After extraction of humic substances (HSs), and their fractionation into fluvic acid (FA) and humic acid (HA), two fluorescent compounds (C1 and C2) were identified and characterized in each physical soil fraction, by means of fluorescence excitation-emission matrices (FEEMs) and Parallel Factor Analysis (PARAFAC). Then, to each type of fraction having similar DOC content, was added an increasing volume of pure BaP solution in attempt to assess the behavior of BaP with the fluorophores present in each one. The application of FEEMs-PARAFAC method validated a three-component model that consisted of the two resulted fluorophores from HSs, FA and HA (C1 and C2) and a BaP-like fluorophore (C3). Spectral modifications were noted for components C2HSs (C2 in humic substances fraction) (λex/λem: 420/490-520 nm), C2FA (C2 in fulvic acid fraction) (λex/λem: 400/487(517) nm) and C1HA (C1 in humic acid fraction) (λex/λem: 350/452(520) nm). We explored the impact of increasing the volume of the added pure BaP solution on the scores of the fluorophores present in the soil fractions. It was found that the scores of C2HSs, C2FA, and C1HA increased when the volume of the added pure BaP solution increased. Superposition of the excitation spectra of these fluorophores with the emission spectrum of BaP showed significant overlaps that might explain the observed interactions between BaP and the fluorescent compounds present in SOM physical fractions.

Plasma appearance and correlation between coffee and green tea metabolites in human subjects.

PubMed

Renouf, Mathieu; Guy, Philippe; Marmet, Cynthia; Longet, Karin; Fraering, Anne-Lise; Moulin, Julie; Barron, Denis; Dionisi, Fabiola; Cavin, Christophe; Steiling, Heike; Williamson, Gary

2010-12-01

Coffee and green tea are two of the most widely consumed hot beverages in the world. Their respective bioavailability has been studied separately, but absorption of their respective bioactive phenolics has not been compared. In a randomised cross-over design, nine healthy subjects drank instant coffee and green tea. Blood samples were collected over 12 h and at 24 h to assess return to baseline. After green tea consumption, (-)-epigallocatechin (EGC) was the major catechin, appearing rapidly in the plasma; (-)-EGC gallate (EGCg) and (-)-epicatechin (EC) were also present, but (-)-EC gallate and C were not detected. Dihydroferulic acid and dihydrocaffeic acid were the major metabolites that appeared after coffee consumption with a long time needed to reach maximum plasma concentration, suggesting metabolism and absorption in the colon. Other phenolic acid equivalents (caffeic acid (CA), ferulic acid (FA) and isoferulic acid (iFA)) were detected earlier, and they peaked at lower concentrations. Summations of the plasma area under the curves (AUC) for the measured metabolites showed 1.7-fold more coffee-derived phenolic acids than green tea-derived catechins (P = 0.0014). Furthermore, we found a significant correlation between coffee metabolites based on AUC. Inter-individual differences were observed, but individuals with a high level of CA also showed a correspondingly high level of FA. However, no such correlation was observed between the tea catechins and coffee phenolic acids. Correlation between AUC and maximum plasma concentration was also significant for CA, FA and iFA and for EGCg. This implies that the mechanisms of absorption for these two classes of compounds are different, and that a high absorber of phenolic acids is not necessarily a high absorber of catechins.

Degradation of polycyclic aromatic hydrocarbons (PAHs) during Sphagnum litters decay.

PubMed

Wang, Zucheng; Liu, Shasha; Bu, Zhao-Jun; Wang, Shengzhong

2018-04-28

The dynamics of polycyclic aromatic hydrocarbon (PAH) degradation in Sphagnum litters and the decomposition of the litters were investigated. PAH concentration decreased to approximately half of the initial concentration as Sphagnum litters decayed. The initial PAH concentration was 489.2 ± 72.2 ng g -1 , and the concentration after 120 days of incubation was 233.0 ± 5.8 ng g -1 . The different PAH compositions changed concentrations at different times. The low-molecular-weight (LMW) and high-molecular-weight (HMW) PAHs started to be degraded after incubation and after 40 days of incubation, respectively. PAH concentrations in the Sphagnum litters correlated with the total organic carbon (TOC) content (p < 0.05), indicating that PAHs were associated with the TOC of the Sphagnum litters and were degraded as organic matter decayed. The positive relationship between LMW PAH concentration and the soluble carbohydrate content (p < 0.05) indicated that LMW PAHs and the readily decomposed organic carbon fractions were cometabolized, or that LMW PAHs were mainly absorbed by soluble carbohydrate. The weak negative correlation between fulvic acid (FA) and PAH concentrations (p < 0.1) indicated that FA may enhance PAH degradation. Redundancy analysis suggested that the contents of both soluble carbohydrate and cellulose significantly affected the changes in PAH concentrations (p < 0.05), and that FA content and C/N ratios may also contribute to the changes in PAH concentrations (p < 0.1). However, the polyphenol that was related to microbial activities was not associated with changes in PAH concentrations. These results suggested that litter quality is more important than microbial activities in PAH degradation in Sphagnum litters.

Simulating Carbon Flux Dynamics with the Product of PAR Absorbed by Chlorophyll (fAPARchl)

NASA Astrophysics Data System (ADS)

Yao, T.; Zhang, Q.

2016-12-01

A common way to estimate the gross primary production (GPP) is to use the fraction of photosynthetically radiation (PAR) absorbed by vegetation (FPAR). However, only the PAR absorbed by chlorophyll of the canopy, not the PAR absorbed by the foliage or by the entire canopy, is used for photosynthesis. MODIS fAPARchl product, which refers to the fraction of PAR absorbed by chlorophyll of the canopy, is derived from Moderate Resolution Imaging Spectroradiometer (MODIS) surface reflectance by using an advanced leaf-canopy-soil-water-snow coupled radiative transfer model PROSAIL4. PROSAIL4 can retrieve surface water cover fraction, snow cover fraction, and physiologically active canopy chemistry components (chlorophyll concentration and water content), fraction of photosynthetically active radiation (PAR) absorbed by a canopy (fAPARcanopy), fraction of PAR absorbed by photosynthetic vegetation (PV) component (mainly chlorophyll) throughout the canopy (fAPARPV, i.e., fAPARchl) and fraction of PAR absorbed by non-photosynthetic vegetation (NPV) component of the canopy (fAPARNPV). We have successfully retrieved these vegetation parameters for selected areas with PROSAIL4 and the MODIS images, or simulated spectrally MODIS-like images. In this study, the product of PAR absorbed by chlorophyll (fAPARchl) has been used to simulate carbon flux over different kinds of vegetation types. The results show that MODIS fAPARchl product has the ability to better characterize phenology than current phenology model in the Community Land Model and it also will likely be able to increase the accuracy of carbon fluxes simulations.

Correlation Between Fractional Anisotropy and Motor Outcomes in One-Year-Old Infants with Periventricular Brain Injury

PubMed Central

Madhavan, Sangeetha; Campbell, Suzann K.; Campise-Luther, Rose; Gaebler-Spira, Deborah; Zawacki, Laura; Clark, April; Boynewicz, Kara; Kale, Dipti; Bulanda, Michelle; Yu, Jinsheng; Sui, Yi; Zhou, Xiaohong Joe

2014-01-01

Purpose To determine whether motor outcomes of an exercise intervention beginning at 2 months corrected age (CA) in children with periventricular brain injury (PBI) are correlated with fractional anisotropy (FA) measures derived from diffusion tensor imaging (DTI) at 12 months CA. Materials and Methods DTI was performed in eight infants with PBI who were randomly assigned to kicking and treadmill stepping exercise or a no-training condition. Development was assessed using the Alberta Infant Motor Scale (AIMS) and the Gross Motor Function Classification System (GMFCS). FA values were derived from regions of interest (ROI) in the middle third of the posterior limb of the internal capsule (PLIC) and the posterior thalamic radiation (PTR). Results Significant correlations were observed between motor development and FA measures. For PLIC, the correlation coefficients were 0.82 between FA and AIMS, and -0.92 between FA and GMFCS, while for PTR the corresponding correlation coefficients were 0.73 and -0.80, respectively. Conclusion Results of this study suggest that quantitative evaluation of white matter tracts using DTI at 12 months CA may be useful for assessment of brain plasticity in children. PMID:24136687

Correlation between fractional anisotropy and motor outcomes in one-year-old infants with periventricular brain injury.

PubMed

Madhavan, Sangeetha; Campbell, Suzann K; Campise-Luther, Rose; Gaebler-Spira, Deborah; Zawacki, Laura; Clark, April; Boynewicz, Kara; Kale, Dipti; Bulanda, Michelle; Yu, Jinsheng; Sui, Yi; Zhou, Xiaohong Joe

2014-04-01

To determine whether motor outcomes of an exercise intervention beginning at 2 months corrected age (CA) in children with periventricular brain injury (PBI) are correlated with fractional anisotropy (FA) measures derived from diffusion tensor imaging (DTI) at 12 months CA. DTI was performed in eight infants with PBI who were randomly assigned to kicking and treadmill stepping exercise or a no-training condition. Development was assessed using the Alberta Infant Motor Scale (AIMS) and the Gross Motor Function Classification System (GMFCS). FA values were derived from regions of interest (ROIs) in the middle third of the posterior limb of the internal capsule (PLIC) and the posterior thalamic radiation (PTR). Significant correlations were observed between motor development and FA measures. For PLIC, the correlation coefficients were 0.82 between FA and AIMS, and -0.92 between FA and GMFCS, while for PTR the corresponding correlation coefficients were 0.73 and -0.80, respectively. Results of this study suggest that quantitative evaluation of white matter tracts using DTI at 12 months CA may be useful for assessment of brain plasticity in children. Copyright © 2013 Wiley Periodicals, Inc.

Determination of trace amount of formaldehyde base on a bromate-Malachite Green system.

PubMed

Tang, Yufang; Chen, Hao; Weng, Chao; Tang, Xiaohui; Zhang, Miaoling; Hu, Tao

2015-01-25

A novel catalytic kinetic spectrophotometric method for determination of trace amount of formaldehyde (FA) has been established, based on catalytic effect of trace amount of FA on the oxidation of Malachite Green (MG) by potassium bromate in presence of sulfuric acid medium, and was reported for the first time. The method was monitored by measuring the decrease in absorbance of MG at 617 nm and allowed a precise determination of FA in the range of 0.003-0.08 μg mL(-1), with a limit of detection down to 1 ng mL(-1). The relative standard deviation of 10 replicate measurements was 1.63%. The method developed was approved to be sensitive, selective and accurate, and adopted to determinate free FA in samples directly with good accuracy and reproducibility. Copyright © 2014 Elsevier B.V. All rights reserved.

Occurrence of fatty acid short-chain-alkyl esters in fruits of Celastraceae plants.

PubMed

Sidorov, Roman A; Zhukov, Anatoly V; Pchelkin, Vasily P; Vereshchagin, Andrei G; Tsydendambaev, Vladimir D

2013-06-01

Small amounts of a mixture of fatty acid short-chain-alkyl esters (FASCAEs) were obtained from the fruits of twelve plant species of Celastraceae family, and in five of them the FASCAEs were present not only in the arils but also in the seeds. These mixtures contained 32 individual FASCAE species, which formed four separate fractions, viz. FA methyl, ethyl, isopropyl, and butyl esters (FAMEs, FAEEs, FAIPEs, and FABEs, resp.). The FASCAE acyl components included the residues of 16 individual C₁₄-C₂₄ saturated, mono-, di-, and trienoic FAs. Linoleic, oleic, and palmitic acids, and, in some cases, also α-linolenic acid predominated in FAMEs and FAEEs, while myristic acid was predominant in FAIPEs. It can be suggested that, in the fruit arils of some plant species, FAMEs and FAEEs were formed at the expense of a same FA pool characteristic of a given species and were strongly different from FAIPEs and FABEs esters regarding the mechanism of their biosynthesis. However, as a whole, the qualitative and quantitative composition of various FASCAE fractions, as well as their FA composition, varied considerably depending on various factors. Therefore, separate FASCAE fractions seem to be synthesized from different FA pools other than those used for triacylglycerol formation. Copyright © 2013 Verlag Helvetica Chimica Acta AG, Zürich.

Perovskite-perovskite tandem photovoltaics with optimized band gaps

NASA Astrophysics Data System (ADS)

Eperon, Giles E.; Leijtens, Tomas; Bush, Kevin A.; Prasanna, Rohit; Green, Thomas; Wang, Jacob Tse-Wei; McMeekin, David P.; Volonakis, George; Milot, Rebecca L.; May, Richard; Palmstrom, Axel; Slotcavage, Daniel J.; Belisle, Rebecca A.; Patel, Jay B.; Parrott, Elizabeth S.; Sutton, Rebecca J.; Ma, Wen; Moghadam, Farhad; Conings, Bert; Babayigit, Aslihan; Boyen, Hans-Gerd; Bent, Stacey; Giustino, Feliciano; Herz, Laura M.; Johnston, Michael B.; McGehee, Michael D.; Snaith, Henry J.

2016-11-01

We demonstrate four- and two-terminal perovskite-perovskite tandem solar cells with ideally matched band gaps. We develop an infrared-absorbing 1.2-electron volt band-gap perovskite, FA0.75Cs0.25Sn0.5Pb0.5I3, that can deliver 14.8% efficiency. By combining this material with a wider-band gap FA0.83Cs0.17Pb(I0.5Br0.5)3 material, we achieve monolithic two-terminal tandem efficiencies of 17.0% with >1.65-volt open-circuit voltage. We also make mechanically stacked four-terminal tandem cells and obtain 20.3% efficiency. Notably, we find that our infrared-absorbing perovskite cells exhibit excellent thermal and atmospheric stability, not previously achieved for Sn-based perovskites. This device architecture and materials set will enable “all-perovskite” thin-film solar cells to reach the highest efficiencies in the long term at the lowest costs.

Internal dosimetry with the Monte Carlo code GATE: validation using the ICRP/ICRU female reference computational model

NASA Astrophysics Data System (ADS)

Villoing, Daphnée; Marcatili, Sara; Garcia, Marie-Paule; Bardiès, Manuel

2017-03-01

The purpose of this work was to validate GATE-based clinical scale absorbed dose calculations in nuclear medicine dosimetry. GATE (version 6.2) and MCNPX (version 2.7.a) were used to derive dosimetric parameters (absorbed fractions, specific absorbed fractions and S-values) for the reference female computational model proposed by the International Commission on Radiological Protection in ICRP report 110. Monoenergetic photons and electrons (from 50 keV to 2 MeV) and four isotopes currently used in nuclear medicine (fluorine-18, lutetium-177, iodine-131 and yttrium-90) were investigated. Absorbed fractions, specific absorbed fractions and S-values were generated with GATE and MCNPX for 12 regions of interest in the ICRP 110 female computational model, thereby leading to 144 source/target pair configurations. Relative differences between GATE and MCNPX obtained in specific configurations (self-irradiation or cross-irradiation) are presented. Relative differences in absorbed fractions, specific absorbed fractions or S-values are below 10%, and in most cases less than 5%. Dosimetric results generated with GATE for the 12 volumes of interest are available as supplemental data. GATE can be safely used for radiopharmaceutical dosimetry at the clinical scale. This makes GATE a viable option for Monte Carlo modelling of both imaging and absorbed dose in nuclear medicine.

[Effect of exercise load on apparent diffusion coefficient and fractional anisotropy of normal lumbar intervertebral discs in diffusion tensor imaging].

PubMed

Zhong, Xiu; Qiu, Shijun

2015-06-01

To investigate the effect of exercise load on apparent diffusion coefficient (ADC) and fractional anisotropy (FA) of normal lumbar intervertebral discs in magnetic resonance (MR) diffusion tensor imaging (DTI). Thirty healthy volunteers (24 males and 6 females, aged 19 to 25 years) underwent examinations with MR T2WI and DTI of the lumbar intervertebral discs before and after exercise load. Pfirrmann grading was evaluated with T2WI, and the B0 map, ADC map and FA map were reconstructed based on the DTI data to investigate the changes in ADC and FA after exercise. Of the 30 volunteers (150 intervertebral discs) receiving the examination, 27 with discs of Pfirrminn grade II were included for analysis. In these 27 volunteers, the average ADC and FA before exercise were (1.99 ± 0.18)×10⁻³ mm²/s and 0.155∓0.059, respectively. After exercise, ADC was lowered significantly to (1.93 ± 0.17)×10⁻³ mm²/s (P<0.05) and FA increased slightly to 0.1623 ± 0.017 (P>0.05). DTI allows quantitatively analysis of the changes in water molecular diffusion and anisotropy of the lumbar intervertebral discs after exercise load, which can cause a decreased ADC and a increased FA value, and the change of ADC is more sensitive to exercise load.

Disrupted white matter integrity in heroin dependence: a controlled study utilizing diffusion tensor imaging.

PubMed

Liu, Haihong; Li, Lin; Hao, Yihui; Cao, Dong; Xu, Lin; Rohrbaugh, Robert; Xue, Zhimin; Hao, Wei; Shan, Baoci; Liu, Zhening

2008-01-01

Fractional anisotropy (FA) via diffusion tensor imaging (DTI) can quantify the white matter integrity. Exposure to addictive drugs, such as alcohol, cocaine, methamphetamine, marijuana, and nicotine has been shown to alter FA. White matter abnormalities have been shown, but it remains unclear whether the white matter FA is altered in heroin dependence. Utilizing DTI, we investigated the FA difference between heroin-dependent and control subjects by a voxel-based strategy. The FA values of the identified regions were calculated from the FA image of each subject and were correlated with clinical features including months of heroin use, age, education, and dose of methadone. Reduced FA among 16 heroin dependent subjects was located in the bilateral frontal sub-gyral regions, right precentral and left cingulate gyrus. FA in the right frontal sub-gyral was negatively correlated with duration of heroin use. The disrupted white matter integrity in right frontal white matter may occur in continuous heroin abuse.

Effects of humic acids with different polarities on the photocatalytic activity of nano-TiO2 at environment relevant concentration.

PubMed

Wu, Wei; Shan, Guoqiang; Xiang, Qian; Zhang, Yinqing; Yi, Shujun; Zhu, Lingyan

2017-10-01

Large volume production and application of nano-TiO 2 make it inevitably release to natural waters and its environmental behaviors would be affected by natural organic matters. In this study, the mechanisms of humic acid (HA) affecting the photocatalytic performance of nano-TiO 2 were elucidated by using three HA fractions from the same source but with different polarities. Bulk HA was fractionated on a silica gel column to get three fractions with polarity increasing in the order of FA, FB and FC. FA was fulvic acid-like while FB and FC were humic acid-like. All the three fractions (at 0.1 mg/L) promoted the generation of hydroxyl radicals (OHs) by nano-TiO 2 , and thus in turn facilitated the photocatalytic degradation of bispheol A (BPA). FA and FC displayed a stronger promotion effect than FB and the bulk HA. Online in situ flow cell ATR-FTIR and XPS analyses indicated that HA fractions could form charge-transfer complex with nano-TiO 2 surface through the phenolic hydroxyl and carboxylic groups, which favored the separation of photogenerated electron-hole pairs. Through step methylation experiments, it was verified that the phenolic hydroxyl and carboxylic groups of HA fractions played important roles in promoting the photocatalytic performance of nano-TiO 2 , and the effect of carboxylic group was more significant than the phenolic hydroxyl group. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of fulvic and humic acids on copper and zinc homeostasis in rats.

PubMed

Hullár, István; Vucskits, András Valentin; Berta, Erzsébet; Andrásofszky, Emese; Bersényi, András; Szabó, József

2018-03-01

The objective of this study was to investigate the effects of fulvic acid (FA) and humic acid (HA), the two main compounds of humic substances (HSs), on copper (Cu) and zinc (Zn) homeostasis. Seventy-two male Wistar rats were randomly divided into nine experimental groups. The control diet (AIN-93G formula) and the diets supplemented with 0.1%, 0.2%, 0.4% and 0.8% FA or HA were fed for 26 days. Cu and Zn concentrations of the large intestinal content (LIC), liver, kidney, femur and hair were determined. FA and HA did not influence significantly the Cu or Zn contents of the experimental diets, the rats' feed intake, weight gain and the feed to gain ratio. Both FA and HA decreased the Cu concentrations of the LIC significantly and in a dose-related manner; however the absorption-stimulating effect of HA was more pronounced. FA increased the Cu content of the liver, but neither FA nor HA had a dose-dependent effect on it. FA or HA supplementations had no significant effect on the Cu concentration of the kidney. At the concentrations used, dietary FA or HA supplementations are not promising growth promoters. FA influences the Cu homeostasis unlike HA, because FA not only stimulates Cu absorption, but the extra quantity of absorbed Cu is retained in the organism. The stimulatory effect of HA on Zn absorption may not be manifested in Cu and Zn homeostasis, because of the tight connection of these microelements to FA and HA, which prevents the transmission of Zn from the ZnHA complex to the organs. As regards the effect of FA and HA on Cu and Zn homeostasis, both FA and HA stimulated the absorption of these microelements, but only FA increased the retention of Cu (in the liver) and Zn (in the kidney).

Sources of organic carbon for Rimicaris hybisae: Tracing individual fatty acids at two hydrothermal vent fields in the Mid-Cayman rise

NASA Astrophysics Data System (ADS)

Streit, Kathrin; Bennett, Sarah A.; Van Dover, Cindy L.; Coleman, Max

2015-06-01

Hydrothermal vents harbor ecosystems mostly decoupled from organic carbon synthesized with the energy of sunlight (photosynthetic carbon source) but fueled instead by oxidation of reduced compounds to generate a chemosynthetic carbon source. Our study aimed to disentangle photosynthetic and chemosynthetic organic carbon sources for the shrimp species Rimicaris hybisae, a primary consumer presumed to obtain its organic carbon mainly from ectosymbiotic chemoautotrophic bacteria living on its gill cover membrane. To provide ectosymbionts with ideal conditions for chemosynthesis, these shrimp live in dense clusters around vent chimneys; they are, however, also found sparsely distributed adjacent to diffuse vent flows, where they might depend on alternative food sources. Densely and sparsely distributed shrimp were sampled and dissected into abdominal tissue and gill cover membrane, covered with ectosymbiotic bacteria, at two hydrothermal vent fields in the Mid-Cayman rise that differ in vent chemistry. Fatty acids (FA) were extracted from shrimp tissues and their carbon isotopic compositions assessed. The FA data indicate that adult R. hybisae predominantly rely on bacteria for their organic carbon needs. Their FA composition is dominated by common bacterial FA of the n7 family (~41%). Bacterial FA of the n4 FA family are also abundant and found to constitute good biomarkers for gill ectosymbionts. Sparsely distributed shrimp contain fractions of n4 FA in gill cover membranes ~4% lower than densely packed ones (~18%) and much higher fractions of photosynthetic FA in abdominal tissues, ~4% more (compared with 1.6%), suggesting replacement of ectosymbionts along with exoskeletons (molt), while they take up alternative diets of partly photosynthetic organic carbon. Abdominal tissues also contain photosynthetic FA from a second source taken up presumably during an early dispersal phase and still present to c. 3% in adult shrimp. The contribution of photosynthetic carbon to the FA pool of adult R. hybisae is, however, overall small (max. 8%). Significant differences in carbon isotopic values of chemosynthetically derived FA between vent fields suggest that different dominant C fixation pathways are being used.

The Driselase-treated fraction of rice bran is a more effective dietary factor to improve hypertension, glucose and lipid metabolism in stroke-prone spontaneously hypertensive rats compared to ferulic acid.

PubMed

Ardiansyah; Shirakawa, Hitoshi; Koseki, Takuya; Hashizume, Katsumi; Komai, Michio

2007-01-01

The aim of this study is to investigate the effects of dietary supplementation with the Driselase-treated fraction (DF) of rice bran and ferulic acid (FA) on hypertension and glucose and lipid metabolism in stroke-prone spontaneously hypertensive rats (SHRSP). Male SHRSP at 4 weeks of age were divided into three groups, and for 8 weeks were fed (1) a control diet based on AIN-93M, (2) a DF of rice bran-supplemented diet at 60 g/kg and (3) an FA-supplemented diet at 0.01 g/kg. Means and standard errors were calculated and the data were tested by one-way ANOVA followed by a least significance difference test. The results showed that both the DF and FA diets significantly improved hypertension as well as glucose tolerance, plasma nitric oxide (NOx), urinary 8-hydroxy-2'-deoxyguanosine and other parameters. In particular, compared to the FA diet, the DF diet produced a significant improvement in urinary NOx, hepatic triacylglycerol and several mRNA expressions of metabolic parameters involved in glucose and lipid metabolisms. The results of the metabolic syndrome-related parameters obtained from this study suggest that the DF diet is more effective than the FA diet.

Insight and white matter fractional anisotropy in first-episode schizophrenia.

PubMed

Asmal, Laila; du Plessis, Stefan; Vink, Matthijs; Fouche, Jean-Paul; Chiliza, Bonginkosi; Emsley, Robin

2017-05-01

Impaired insight is a hallmark feature of schizophrenia. Structural studies implicate predominantly prefrontal, cingulate, cuneus/precuneus, and inferior temporal brain regions. The cortical midline structures (CMS) are also implicated in functional studies primarily through self-reflective processing tasks. However, few studies have explored the relationship between white matter tracts and insight in schizophrenia, and none in first-episode schizophrenia (FES). Here, we examined for fractional anisotropy (FA) differences in 89 minimally treated FES patients and 98 matched controls, and identified those FA differences associated with impaired clinical insight in patients. We found widespread FA reduction in FES patients compared to controls. Poorer insight in patients was predicted by lower FA values in a number of white matter tracts with a predilection for tracts associated with cortical midline structures (fronto-occipital, cingulate, cingulate hippocampus, uncinate, anterior corona radiata), and more severe depressive symptoms. The association between FA abnormalities and insight was most robust for the awareness of symptoms and illness awareness domains. Our study implicates a network of tracts involved in impaired insight in schizophrenia with a predilection for the CMS. This study is a first step in delineating the white matter tracts involved in insight impairment in schizophrenia prior to chronicity. Copyright © 2016. Published by Elsevier B.V.

White matter microstructure in boys with persistent depressive disorder.

PubMed

Vilgis, Veronika; Vance, Alasdair; Cunnington, Ross; Silk, Timothy J

2017-10-15

Persistent depressive symptoms in children and adolescents are considered a risk factor for the development of major depressive disorder (MDD) later in life. Previous research has shown alterations in white matter microstructure in pediatric MDD but discrepancies exist as to the specific tracts affected. The current study aimed to improve upon previous methodology and address the question whether previous findings of lower fractional anisotropy (FA) replicate in a sample of children with persistent depressive disorder characterized by mild but more chronic symptoms of depression. White matter microstructure was examined in 25 boys with persistent depressive disorder and 25 typically developing children. Tract specific analysis implemented with the Diffusion Tensor Imaging - ToolKit (DTI-TK) was used to probe fractional anisotropy (FA) in eleven major white matter tracts. Clusters within the left uncinate, inferior fronto-occipital and cerebrospinal tracts showed lower FA in the clinical group. FA in the left uncinate showed a negative association with self-reported symptoms of depression. The results demonstrate lower FA in several white matter tracts in children with persistent depressive disorder. These findings support the contention that early onset depression is associated with altered white matter microstructure, which may contribute to the maintenance and recurrence of symptoms. Copyright © 2017. Published by Elsevier B.V.

Insights into the effects of polygalacturonase FaPG1 gene silencing on pectin matrix disassembly, enhanced tissue integrity, and firmness in ripe strawberry fruits

PubMed Central

Posé, Sara; Paniagua, Candelas; Cifuentes, Manuel; Blanco-Portales, Rosario; Quesada, Miguel A.; Mercado, José A.

2013-01-01

Antisense-mediated down-regulation of the fruit-specific polygalacturonase (PG) gene FaPG1 in strawberries (Fragaria×ananassa Duch.) has been previously demonstrated to reduce fruit softening and to extend post-harvest shelf life, despite the low PG activity detected in this fruit. The improved fruit traits were suggested to be attributable to a reduced cell wall disassembly due to FaPG1 silencing. This research provides empirical evidence that supports this assumption at the biochemical, cellular, and tissue levels. Cell wall modifications of two independent transgenic antisense lines that demonstrated a >90% reduction in FaPG1 transcript levels were analysed. Sequential extraction of cell wall fractions from control and ripe fruits exhibited a 42% decrease in pectin solubilization in transgenic fruits. A detailed chromatographic analysis of the gel filtration pectin profiles of the different cell wall fractions revealed a diminished depolymerization of the more tightly bound pectins in transgenic fruits, which were solubilized with both a chelating agent and sodium carbonate. The cell wall extracts from antisense FaPG1 fruits also displayed less severe in vitro swelling. A histological analysis revealed more extended cell–cell adhesion areas and an enhanced tissue integrity in transgenic ripe fruits. An immunohistological analysis of fruit sections using the JIM5 antibody against low methyl-esterified pectins demonstrated a higher labelling in transgenic fruit sections, whereas minor differences were observed with JIM7, an antibody that recognizes highly methyl-esterified pectins. These results support that the increased firmness of transgenic antisense FaPG1 strawberry fruits is predominantly due to a decrease in pectin solubilization and depolymerization that correlates with more tightly attached cell wall-bound pectins. This limited disassembly in the transgenic lines indicates that these pectin fractions could play a key role in tissue integrity maintenance that results in firmer ripe fruit. PMID:23873994

Folic acid prevents cardiac dysfunction and reduces myocardial fibrosis in a mouse model of high-fat diet-induced obesity.

PubMed

Li, Wei; Tang, Renqiao; Ouyang, Shengrong; Ma, Feifei; Liu, Zhuo; Wu, Jianxin

2017-01-01

Folic acid (FA) is an antioxidant that can reduce reactive oxygen species generation and can blunt cardiac dysfunction during ischemia. We hypothesized that FA supplementation prevents cardiac fibrosis and cardiac dysfunction induced by obesity. Six-week-old C57BL6/J mice were fed a high-fat diet (HFD), normal diet (ND), or an HFD supplemented with folic acid (FAD) for 14 weeks. Cardiac function was measured using a transthoracic echocardiographic exam. Phenotypic analysis included measurements of body and heart weight, blood glucose and tissue homocysteine (Hcy) content, and heart oxidative stress status. HFD consumption elevated fasting blood glucose levels and caused obesity and heart enlargement. FA supplementation in HFD-fed mice resulted in reduced fasting blood glucose, heart weight, and heart tissue Hcy content. We also observed a significant cardiac systolic dysfunction when mice were subjected to HFD feeding as indicated by a reduction in the left ventricular ejection fraction and fractional shortening. However, FAD treatment improved cardiac function. FA supplementation protected against cardiac fibrosis induced by HFD. In addition, HFD increased malondialdehyde concentration of the heart tissue and reduced the levels of antioxidant enzyme, glutathione, and catalase. HFD consumption induced myocardial oxidant stress with amelioration by FA treatment. FA supplementation significantly lowers blood glucose levels and heart tissue Hcy content and reverses cardiac dysfunction induced by HFD in mice. These functional improvements of the heart may be mediated by the alleviation of oxidative stress and myocardial fibrosis.

Diversity of fatty acid composition of symbiotic dinoflagellates in corals: evidence for the transfer of host PUFAs to the symbionts.

PubMed

Imbs, Andrey B; Yakovleva, Irina M; Dautova, Tatiana N; Bui, Long H; Jones, Paul

2014-05-01

High diversity of fatty acid (FA) composition of endosymbiotic dinoflagellates of the Symbiodinium group (zooxanthellae) isolated from different cnidarian groups has been found. To explain this diversity, FA composition of the total lipids of pure symbiont fractions (SF) and host cell tissue fractions (HF) isolated from one hydrocoral, two soft coral, and seven hard coral species inhabiting the shallow waters of the South China Sea (Vietnam) were compared. Symbiodinium phylogenetic clade designation for each SF was also determined, however, the relationship between the clade designation and FA composition of Symbiodinium was not found. The profiles of marker polyunsaturated FAs (PUFAs) of symbionts (18:4n-3, 18:5n-3, 20:5n-3) did not depend on taxonomic designation of the host and reflected only a specimen-specific diversity of the SF lipids. Several FAs such as 20:0, C24 PUFAs, 22:5n-6, and 18:2n-7 concentrated in HF lipids but were also found in SF lipids. For ten cnidarian species studied, the principal components analysis of total FAs (27 variables) of the symbiotic fractions was performed. The clear division of the symbiotic dinoflagellates according to the host systematic identity was found on a subclass level. This division was mainly caused by the FAs specific for the host lipids of each cnidarian subclasses such as hard corals, soft corals, and hydrocorals. Thus, the coral hosts affect the FA profile of their symbionts and cause the diversity of FA composition of Symbiodinium. The transfer of FAs from the coral host to their symbiotic dinoflagellates and modulation of PUFA biosynthesis in symbionts by the host are considered as possible reasons of the diversity studied. Copyright © 2014 Elsevier Ltd. All rights reserved.

‘One-pot’ synthesis of multifunctional GSH-CdTe quantum dots for targeted drug delivery

NASA Astrophysics Data System (ADS)

Chen, Xiaoqin; Tang, Yajun; Cai, Bing; Fan, Hongsong

2014-06-01

A novel quantum dots-based multifunctional nanovehicle (DOX-QD-PEG-FA) was designed for targeted drug delivery, fluorescent imaging, tracking, and cancer therapy, in which the GSH-CdTe quantum dots play a key role in imaging and drug delivery. To exert curative effects, the antineoplastic drug doxorubicin hydrochloride (DOX) was loaded on the GSH-CdTe quantum dots through a condensation reaction. Meanwhile, a polyethylene glycol (PEG) shell was introduced to wrap the DOX-QD, thus stabilizing the structure and preventing clearance and drug release during systemic circulation. To actively target cancer cells and prevent the nanovehicles from being absorbed by normal cells, the nanoparticles were further decorated with folic acid (FA), allowing them to target HeLa cells that express the FA receptor. The multifunctional DOX-QD-PEG-FA conjugates were simply prepared using the ‘one pot’ method. In vitro study demonstrated that this simple, multifunctional nanovehicle can deliver DOX to the targeted cancer cells and localize the nanoparticles. After reaching the tumor cells, the FA on the DOX-QD-PEG surface allowed folate receptor recognition and increased the drug concentration to realize a higher curative effect. This novel, multifunctional DOX-QD-PEG-FA system shows great potential for tumor imaging, targeting, and therapy.

Reduced fractional anisotropy on diffusion tensor magnetic resonance imaging after hypoxic-ischemic encephalopathy.

PubMed

Ward, Phil; Counsell, Serena; Allsop, Joanna; Cowan, Frances; Shen, Yuji; Edwards, David; Rutherford, Mary

2006-04-01

Apparent diffusion coefficients (ADC) that are measured by diffusion-weighted imaging are reduced in severe white matter (WM) and in some severe basal ganglia and thalamic (BGT) injury in infants who present with hypoxic-ischemic encephalopathy (HIE). However, ADC values may pseudonormalize or even be high during this time in some less severe but clinically significant injuries. We hypothesized that fractional anisotropy (FA), a measure of the directional diffusivity of water made using diffusion tensor imaging, may be abnormal in these less severe injuries; therefore, the objective of this study was to use diffusion tensor imaging to measure ADC and FA in infants with moderate and severe hypoxic-ischemic brain injury. Twenty infants with HIE and 7 normal control infants were studied. All infants were born at >36 weeks' gestational age, and MRI scans were obtained within 3 weeks of delivery. Data were examined for normality, and comparisons were made using analysis of variance or Kruskal-Wallis as appropriate. During the first week, FA values were decreased with both severe and moderate WM and BGT injury as assessed by conventional imaging, whereas ADC values were reduced only in severe WM injury and some severe BGT injury. Abnormal ADC values pseudonormalized during the second week, whereas FA values continued to decrease. FA is reduced in moderate brain injury after HIE. A low FA may reflect a breakdown in WM organization. Moderate BGT injury may result in atrophy but not overt infarction; it is possible that delayed apoptosis is more marked than immediate necrosis, and this may account for normal early ADC values. The accompanying low FA within some severe and all moderate gray matter lesions, which is associated with significant later impairment, may help to confirm clinically significant abnormality in infants with normal ADC values.

Schizophrenia symptomatic associations with diffusion tensor imaging measured fractional anisotropy of brain: a meta-analysis.

PubMed

Yang, Xu; Cao, Ding; Liang, Xiumei; Zhao, Jiannong

2017-07-01

Several studies have examined the relationships between diffusion tensor imaging (DTI)-measured fractional anisotropy (FA) and the symptoms of schizophrenia, but results vary across the studies. The aim of this study was to carry out a meta-analysis of correlation coefficients reported by relevant studies to evaluate the correlative relationships between FA of various parts of the brain and schizophrenia symptomatic assessments. Literature was searched in several electronic databases, and study selection was based on précised eligibility criteria. Correlation coefficients between FA of a part of the brain and schizophrenia symptom were first converted into Fisher's z-scores for meta-analyses, and then overall effect sizes were back transformed to correlation coefficients. Thirty-three studies (1121 schizophrenia patients; age 32.66 years [95% confidence interval (CI) 30.19, 35.13]; 65.95 % [57.63, 74.28] males) were included in this meta-analysis. Age was inversely associated with brain FA (z-scores [95% CI] -0.23 [-0.14, -0.32]; p ˂ 0.00001). Brain FA of various areas was inversely associated with negative symptoms of schizophrenia (z-score -0.30 [-0.23, -0.36]; p ˂ 0.00001) but was positively associated with positive symptoms of schizophrenia (z-score 0.16 [0.04, 0.27]; p = 0.007) and general psychopathology of schizophrenia (z-score 0.26 [0.15, 0.37]; p = 0.00001). Although, DTI-measured brain FA is found to be inversely associated with negative symptoms and positively associated with positive symptoms and general psychopathology of schizophrenia, the effect sizes of these correlations are low and may not be clinically significant. Moreover, brain FA was also negatively associated with age of patients.

Measurement and modeling of diffusion time dependence of apparent diffusion coefficient and fractional anisotropy in prostate tissue ex vivo.

PubMed

Bourne, Roger; Liang, Sisi; Panagiotaki, Eleftheria; Bongers, Andre; Sved, Paul; Watson, Geoffrey

2017-10-01

The purpose of this study was to measure and model the diffusion time dependence of apparent diffusion coefficient (ADC) and fractional anisotropy (FA) derived from conventional prostate diffusion-weighted imaging methods as used in recommended multiparametric MRI protocols. Diffusion tensor imaging (DTI) was performed at 9.4 T with three radical prostatectomy specimens, with diffusion times in the range 10-120 ms and b-values 0-3000 s/mm 2 . ADC and FA were calculated from DTI measurements at b-values of 800 and 1600 s/mm 2 . Independently, a two-component model (restricted isotropic plus Gaussian anisotropic) was used to synthesize DTI data, from which ADC and FA were predicted and compared with the measured values. Measured ADC and FA exhibited a diffusion time dependence, which was closely predicted by the two-component model. ADC decreased by about 0.10-0.15 μm 2 /ms as diffusion time increased from 10 to 120 ms. FA increased with diffusion time at b-values of 800 and 1600 s/mm 2 but was predicted to be independent of diffusion time at b = 3000 s/mm 2 . Both ADC and FA exhibited diffusion time dependence that could be modeled as two unmixed water pools - one having isotropic restricted dynamics, and the other unrestricted anisotropic dynamics. These results highlight the importance of considering and reporting diffusion times in conventional ADC and FA calculations and protocol recommendations, and inform the development of improved diffusion methods for prostate cancer imaging. Copyright © 2017 John Wiley & Sons, Ltd.

Total organic carbon and humus fractions in restored soils from limestone quarries in semiarid climate, SE Spain

NASA Astrophysics Data System (ADS)

Luna Ramos, Lourdes; Miralles Mellado, Isabel; Ángel Domene Ruiz, Miguel; Solé Benet, Albert

2016-04-01

Mining activities generate erosion and loss of plant cover and soil organic matter (SOM), especially in arid and semiarid Mediterranean regions. A precondition for ecosystem restoration in such highly disturbed areas is the development of functional soils with sufficient organic matter. But the SOM quality is also important to long-term C stabilization. The resistance to biodegradation of recalcitrant organic matter fractions has been reported to depend on some intrinsic structural factors of humic acid substances and formation of amorphous organo-mineral recalcitrant complexes. In an experimental soil restoration in limestone quarries in the Sierra de Gádor (Almería), SE Spain, several combinations of organic amendments (sewage sludge and compost from domestic organic waste) and mulches (gravel and woodchip) were added in experimental plots using a factorial design. In each plot, 75 native plants (Anthyllis cytisoides, A. terniflora and Macrochloa tenacissima) were planted and five years after the start of the experiment total organic carbon (TOC), physico-chemical soil properties and organic C fractions (particulate organic matter, H3PO4-fulvic fraction, fulvic acids (FA), humic acids (HA) and humin) were analyzed. We observed significant differences between treatments related to the TOC content and the HA/FA ratio. Compost amendments increased the TOC, HA content and HA/FA ratio, even higher than in natural undisturbed soils, indicating an effective clay humus-complex pointing to progressively increasing organic matter quality. Soils with sewage sludge showed the lowest TOC and HA/FA ratio and accumulated a lower HA proportion indicating poorer organic matter quality and comparatively lower resilience than in natural soils and soils amended with compost.

Induction of chlamydospore formation in fusarium by cyclic lipopeptide antibiotics from Bacillus subtilis C2.

PubMed

Li, Lei; Ma, Mingchuan; Huang, Rong; Qu, Qing; Li, Guohong; Zhou, Jinwei; Zhang, Keqin; Lu, Kaiping; Niu, Xuemei; Luo, Jun

2012-08-01

The culture filtrate of Bacillus subtilis strain C2 showed strong activity against the pathogenic fungus Fusarium solani f. sp. radicicola. A partially purified fraction (PPF) from the extract induced chlamydospore formation in Fusarium. Reverse-phase high performance liquid chromatography yielded 8 different fractions, six of which had chlamydospore-inducing activity. Mass spectrometry and nuclear magnetic resonance analyses identified the main active constituent as C(17) fengycin A (FA17), a cyclic lipopeptide. The effect of FA17 on morphology and physiology of two Fusarium species was dependent on the lipopeptide concentration. When challenged with FA17 at concentrations (0.5, 8, 64 μg ml(-1)) below the minimum inhibitory concentration (MIC) (128 μg ml(-1)), two species of Fusarium formed chlamydospores from hyphae, germ tubes, or inside the conidia within 2 days. At concentrations close to the MIC, FA17 caused Fusarium to form sparse and swollen hyphae or lysed conidia. The other five fractions were identified as fengycin A homologues. The homologues could also induce chlamydospore-like structures in 17 species of filamentous fungi including some specimens that do not normally produce chlamydospores, according to their taxonomic descriptions. Like other chlamydospores, these structures contained nuclei and lipid bodies as revealed by DAPI and Nile Red staining, and could germinate. This is the first study to demonstrate that under laboratory conditions fengycin, an antifungal lipopeptide produced by B. subtilis, can induce chlamydospore formation in Fusarium and chlamydospore-like structures in many filamentous fungi.

Analysis of radiological parameters associated with decreased fractional anisotropy values on diffusion tensor imaging in patients with lumbar spinal stenosis.

PubMed

Wang, Xiandi; Wang, Hongli; Sun, Chi; Zhou, Shuyi; Meng, Tao; Lv, Feizhou; Ma, Xiaosheng; Xia, Xinlei; Jiang, Jianyuan

2018-04-26

Previous studies have indicated that decreased fractional anisotropy (FA) values on diffusion tensor imaging (DTI) are well correlated with the symptoms of nerve root compression. The aim of our study is to determine primary radiological parameters associated with decreased FA values in patients with lumbar spinal stenosis involving single L5 nerve root. Patients confirmed with single L5 nerve root compression by transforaminal nerve root blocks were included in this study. FA values of L5 nerve roots on both symptomatic and asymptomatic side were obtained. Conventional radiological parameters, such as disc height, degenerative scoliosis, dural sac cross-sectional area (DSCSA), foraminal height (FH), hypertrophic facet joint degeneration (HFJD), sagittal rotation (SR), sedimentation sign, sagittal translation and traction spur were measured. Correlation and regression analyses were performed between the radiological parameters and FA values of the symptomatic L5 nerve roots. A predictive regression equation was established. Twenty-one patients were included in this study. FA values were significantly lower at the symptomatic side comparing to the asymptomatic side (0.263 ± 0.069 vs. 0.334 ± 0.080, P = 0.038). DSCSA, FH, HFJD, and SR were significantly correlated with the decreased FA values, with r = 0.518, 0.443, 0.472 and - 0.910, respectively (P < 0.05). DSCSA and SR were found to be the primary radiological parameters related to the decreased FA values, and the regression equation is FA = - 0.012 × SR + 0.002 × DSCSA. DSCSA and SR were primary contributors to decreased FA values in LSS patients involving single L5 nerve root, indicating that central canal decompression and segmental stability should be the first considerations in preoperative planning of these patients. These slides can be retrieved under Electronic Supplementary Material.

Outcome assessment of hemiparesis due to intracerebral hemorrhage using diffusion tensor fractional anisotropy.

PubMed

Koyama, Tetsuo; Marumoto, Kohei; Uchiyama, Yuki; Miyake, Hiroji; Domen, Kazuhisa

2015-04-01

This study aimed to evaluate the prognostic efficacy of magnetic resonance diffusion tensor fractional anisotropy (FA) for patients with hemiparesis due to intracerebral hemorrhage. Diffusion tensor FA brain images were acquired 14-21 days after putaminal and/or thalamic hemorrhage. The ratio of FA values within the cerebral peduncles of the affected and unaffected hemispheres (rFA) was calculated for each patient (n = 40) and assessed for correlation with Brunnstrom stage (BRS, 1-6), motor component of the functional independence measure (FIM-motor, 13-91), and the total length of stay (LOS) until discharge from rehabilitation (P < .05). Ordinal logistic regression analyses were conducted to determine the relationships between rFA and specific outcomes as measured by BRS range (poor, BRS 1 or 2; moderate, BRS 3 or 4; and good, BRS 5 or 6; P < .05). The rFA values were .571-1.043 (median, .856) and BRS scores were 1-6 (median, 4) for shoulder/elbow/forearm, 1-6 (median, 4) for hand, and 2-6 (median, 4) for lower extremities. FIM-motor scores were 58-86 (median, 78) and LOS ranged from 42 to 225 days (median, 175.5 days). Correlation coefficients were statistically significant between rFA and shoulder/elbow/forearm BRS (.696), hand BRS (.779), lower extremity BRS (.631), FIM-motor (.442), and LOS (-.598). Logistic model fit was moderate for shoulder/elbow/forearm BRS (R(2) = .221) and lower extremity BRS (R(2) = .277), but was much higher for hand BRS (R(2) = .441). Diffusion tensor FA values are predictive of clinical outcome from hemiparesis due to putaminal and/or thalamic hemorrhage, particularly hand function recovery. Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Droplet digital PCR analysis of NOTCH1 gene mutations in chronic lymphocytic leukemia.

PubMed

Minervini, Angela; Francesco Minervini, Crescenzio; Anelli, Luisa; Zagaria, Antonella; Casieri, Paola; Coccaro, Nicoletta; Cumbo, Cosimo; Tota, Giuseppina; Impera, Luciana; Orsini, Paola; Brunetti, Claudia; Giordano, Annamaria; Specchia, Giorgina; Albano, Francesco

2016-12-27

In chronic lymphocytic leukemia (CLL), NOTCH1 gene mutations (NOTCH1mut) have been associated with adverse prognostic features but the independence of these as a prognostic factor is still controversial. In our study we validated a c.7541-7542delCT NOTCH1 mutation assay based on droplet digital PCR (ddPCR); we also analyzed the NOTCH1mut allelic burden, expressed as fractional abundance (FA), in 88 CLL patients at diagnosis to assess its prognostic role and made a longitudinal ddPCR analysis in 10 cases harboring NOTCH1mut to verify the FA variation over time. Our data revealed that with the ddPCR approach the incidence of NOTCH1mut in CLL was much higher (53.4%) than expected. However, longitudinal ddPCR analysis of CLL cases showed a statistically significant reduction of the NOTCH1mut FA detected at diagnosis after treatment (median FA 11.67 % vs 0.09 %, respectively, p = 0.01); the same difference, in terms of NOTCH1mut FA, was observed in the relapsed cases compared to the NOTCH1mut allelic fraction observed in patients in complete or partial remission (median FA 4.75% vs 0.43%, respectively, p = 0.007). Our study demonstrated a much higher incidence of NOTCH1mut in CLL than has previously been reported, and showed that the NOTCH1mut allelic burden evaluation by ddPCR might identify patients in need of a closer clinical follow-up during the "watch and wait" interval and after standard chemotherapy.

Fatty Acid Profile of Sunshine Bass: II. Profile Change Differs Among Fillet Lipid Classes.

PubMed

Trushenski, Jesse T; Lewis, Heidi A; Kohler, Christopher C

2008-07-01

Fatty acid (FA) profile of fish tissue mirrors dietary FA profile and changes in a time-dependent manner following a change in dietary FA composition. To determine whether FA profile change varies among lipid classes, we evaluated the FA composition of fillet cholesteryl esters (CE), phospholipids (PL), and triacylglycerols (TAG) of sunshine bass (SB, Morone chrysops x M. saxatilis) raised on feeds containing fish oil or 50:50 blend of fish oil and coconut, grapeseed, linseed, or poultry oil, with or without implementation of a finishing period (100% FO feed) prior to harvest. Each lipid class was associated with a generalized FA signature, irrespective of nutritional history: fillet PL was comprised largely of saturated FA (SFA), long-chain polyunsaturated FA (LC-PUFA), and total n-3 FA; fillet TAG was higher in MC-PUFA and total n-6 FA; and fillet CE was highest in monounsaturated FA (MUFA). Neutral lipids reflected dietary composition in a near-direct fashion; conversely, PL showed evidence of selectivity for MC- and LC-PUFA. Shorter-chain SFA were not strongly reflected within any lipid fraction, even when dietary availability was high, suggesting catabolism of these FA. FA metabolism in SB is apparently characterized by a division between saturated and unsaturated FA, whereby LC-PUFA are preferentially incorporated into tissues and SFA are preferentially oxidized for energy production. We demonstrated provision of SFA in grow-out feeds for SB, instead MC-PUFA which compete for tissue deposition, meets energy demands and allows for maximum inclusion of LC-PUFA within fillet lipids.

Immunological relationships between glucosyltransferases from Streptococcus mutans serotypes.

PubMed

Kuramitsu, H; Ingersoll, L

1976-09-01

Partially purified glycosyltransferase enzymes for Streptococcus mutans GS-5 (serotype c) have been utilized to prepare antibodies directed against the soluble glucan-synthesizing activity, GTF-B, and the insoluble-soluble glucan synthetic activity, GTF-A. Anti-GTF-A inhibited insoluble glucan formation catalyzed by the extracellular enzymes from strains GS-5 and FA-1 (serotype b) to a much greater extent than that of strains HS-6 (serotype a) or OMZ-176 (serotype d). This antibody fraction also inhibited both the cell-associated glucosyltransferase activities as well as the sucrose-mediated adherence of cells to glass surfaces by strains GS-5 and FA-1 but not that of strains HS-6 and OMZ-176. Anti-GTF-B inhibited soluble glucan formation catalyzed by the extracellular enzymes of strains GS-5 but not that of strain HS-6, FA-1, or OMZ-176. However, this antibody fraction did not strongly inhibit either the cell-associated glycosyltransferase activity or cellular adherence of any of the four strains. These results with body antibody fractions were also correlated with the ability of the antibodies to agglutinate the cells and form precipitin bands after immunodiffusion with the extracellular enzymes. Antibody prepared against the homogeneous soluble glucan-synthesizing enzyme demonstrated similar effects to the anti-GTF-B fraction. These results are discussed in terms of the antigenic relationships existing between the glucosyltransferases from different serotypes of S. mutans.

CAPILLARY ISOELECTRIC FOCUSING (CIEF) FOR THE CHARACTERIZATION OF HUMIC SUBSTANCES

EPA Science Inventory

Preparative solution isoelectric focusing was used to fractionate 50 mg of a soil fulvic acid (FA); the harvested fractions were characterized with UV-Vis spectroscopy, gel permeation chromatography and capillary zone electrophoresis (CZE) and showed a distribution in the created...

Alterations in frontal white matter neurochemistry and microstructure in schizophrenia: implications for neuroinflammation.

PubMed

Chiappelli, J; Hong, L E; Wijtenburg, S A; Du, X; Gaston, F; Kochunov, P; Rowland, L M

2015-04-14

We investigated in vivo neurochemical markers reflective of neuronal health and glial activation to determine if these could yield clues regarding the reduced fractional anisotropy (FA) of white matter and accelerated decline of FA with age in schizophrenia. Participants with schizophrenia and healthy controls completed diffusion tensor imaging to assess FA and proton magnetic resonance spectroscopy to assess neurochemical metabolites in the same frontal region. Frontal FA was significantly lower in the schizophrenia and declined more rapidly with age compared with the healthy control group. In both groups, N-acetylaspartate (NAA), a putative marker of neuronal integrity, and glutamate declined with age, and this decline was stronger in patients. Myo-inositol, a marker of glial cells, was negatively related to FA in both groups. The relationship between FA and age remained significant in schizophrenia even when controlling for all metabolites. The relationships of FA, NAA and myo-inositol to age appear to be independent of one another. The relationship between FA and myo-inositol was independently present in both patients and controls, even after controlling for age, indicating a potential general effect of neuroinflammation on white matter microstructure. Further studies are warranted to determine the underlying mechanism driving the accelerated FA decline with age in schizophrenia.

Characterization of FaDu-R, a radioresistant head and neck cancer cell line, and cancer stem cells.

PubMed

Cho, Kwang-Jae; Park, Eun-Ji; Kim, Min-Sik; Joo, Young-Hoon

2018-06-01

The aim of this study was to evaluate the impact of CSC on insensitivity to radiotherapy in HNSCC. A radioresistant cell line, FaDu-R, was established using fractionated ionizing radiation. Cells with high and low CD44/ALDH activity were isolated. FaDu-R cells demonstrated significantly increased cell viability after radiation exposure compared with parental cells. CD44 high /ALDH high FaDu-R cells demonstrated significantly faster wound closure (p<0.05) and more efficient invasion (p<0.05) compared to the CD44 high /ALDH high FaDu cells or the CD44 low /ALDH low FaDu-R cells. There was a significant difference in tumor volume between the CD44 high /ALDH high FaDu-R cells and the CD44 high /ALDH high FaDu cells (p<0.05) as well as the CD44 low /ALDH low FaDu-R cells (p<0.05). Cancer stem cells (CSC) were associated with invasion and tumorigenesis in a radioresistant head and neck squamous cell carcinoma (HNSCC) cell line. This concept might help to improve the understanding of these mechanisms and to develop drugs that can overcome radioresistance during radiotherapy. Copyright © 2017 Elsevier B.V. All rights reserved.

Comprehensive comparison of the chemical and structural characterization of landfill leachate and leonardite humic fractions.

PubMed

Tahiri, Abdelghani; Richel, Aurore; Destain, Jacqueline; Druart, Philippe; Thonart, Philippe; Ongena, Marc

2016-03-01

Humic substances (HS) are complex and heterogeneous mixtures of organic compounds that occur everywhere in the environment. They represent most of the dissolved organic matter in soils, sediments (fossil), water, and landfills. The exact structure of HS macromolecules has not yet been determined because of their complexity and heterogeneity. Various descriptions of HS are used depending on specific environments of origin and research interests. In order to improve the understanding of the structure of HS extracted from landfill leachate (LHS) and commercial HS from leonardite (HHS), this study sought to compare the composition and characterization of the structure of LHS and HHS using elemental composition, chromatographic (high-performance liquid chromatography (HPLC)), and spectroscopic techniques (UV-vis, FTIR, NMR, and MALDI-TOF). The results showed that LHS molecules have a lower molecular weight and less aromatic structure than HHS molecules. The characteristics of functional groups of both LHS and HHS, however, were basically similar, but there was some differences in absorbance intensity. There were also less aliphatic and acidic functional groups and more aromatic and polyphenolic compounds in the humic acid (HA) fraction than in the fulvic acid (FA) and other molecules (OM) fractions of both origins. The differences between LHS and HHS might be due to the time course of humification. Combining the results obtained from these analytical techniques cold improve our understanding of the structure of HS of different origins and thus enhance their potential use.

White matter alterations in temporal lobe epilepsy

NASA Astrophysics Data System (ADS)

Diniz, P. B.; Salmon, C. E.; Velasco, T. R.; Sakamoto, A. C.; Leite, J. P.; Santos, A. C.

2011-03-01

In This study, we used Fractional anisotropy (FA), mean diffusivity (D), parallel diffusivity (D//) and perpendicular diffusivity (D), to localize the regions where occur axonal lesion and demyelization. TBSS was applied to analyze the FA data. After, the regions with alteration were studied with D, D// and D maps. Patients exhibited widespread degradation of FA. With D, D// and D maps analysis we found alterations in corpus callosum, corticospinal tract, fornix, internal capsule, corona radiate, Sagittal stratum, cingulum, fronto-occipital fasciculus and uncinate fasciculus. Our results are consistent with the hypothesis that exist demyelization and axonal damage in patients with TLE.

Release kinetics of esterified p-coumaric acid and ferulic acid from rice straw in mild alkaline solution.

PubMed

Linh, Tran Ngoc; Fujita, Hirokata; Sakoda, Akiyoshi

2017-05-01

The release kinetics of esterified p-coumaric acid (PCA) and ferulic acid (FA) from rice straw under a mild alkaline condition were investigated to collect fundamental data for the design of a recovery process. The results showed that the straw size, NaOH concentration, and temperature were the key parameters governing release kinetics. The analysis demonstrated that FA is released considerably faster than PCA. The close relationship between lignin and the PCA dissolution indicates a reciprocal and/or simultaneous release. Moreover, PCA is broadly distributed in the lignin network but tends to be located more densely in the lignin fraction which is not easily solubilized by alkaline treatment. In contrast, the release of FA is strongly affected by removal of lignin fraction which is easily solubilized. These results suggest that the release kinetics are controlled by the accessibility of NaOH to their ester sites in the lignin/hemicellulose network, and by their localization. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of Oral Lipid Matrix Supplement on Fat Absorption in Cystic Fibrosis: A Randomized Placebo-Controlled Trial.

PubMed

Stallings, Virginia A; Schall, Joan I; Maqbool, Asim; Mascarenhas, Maria R; Alshaikh, Belal N; Dougherty, Kelly A; Hommel, Kevin; Ryan, Jamie; Elci, Okan U; Shaw, Walter A

2016-12-01

Pancreatic enzyme therapy does not normalize dietary fat absorption in patients with cystic fibrosis and pancreatic insufficiency. Efficacy of LYM-X-SORB (LXS), an easily absorbable lipid matrix that enhances fat absorption, was evaluated in a 12-month randomized, double-blinded, placebo-controlled trial with plasma fatty acids (FA) and coefficient of fat absorption (CFA) outcomes. A total of 110 subjects (age 10.4 ± 3.0 years) were randomized. Total FA increased with LXS at 3 and 12 months (+1.58, +1.14 mmol/L) and not with placebo (P = 0.046). With LXS, linoleic acid (LA) increased at 3 and 12 months (+298, +175 nmol/mL, P ≤ 0.046), with a 6% increase in CFA (P < 0.01). LA increase was significant in LXS versus placebo (445 vs 42 nmol/mL, P = 0.038). Increased FA and LA predicted increased body mass index Z scores. In summary, the LXS treatment improved dietary fat absorption compared with placebo as indicated by plasma FA and LA and was associated with better growth status.

Stable Formamidinium-Based Perovskite Solar Cells via In Situ Grain Encapsulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Kai; Li, Zhen; Yang, Ye

Formamidinium (FA)-based lead iodide perovskites have emerged as the most promising light-absorber materials in the prevailing perovskite solar cells (PSCs). However, they suffer from the phase-instability issue in the ambient atmosphere, which is holding back the realization of the full potential of FA-based PSCs in the context of high efficiency and stability. Herein, the tetraethylorthosilicate hydrolysis process is integrated with the solution crystallization of FA-based perovskites, forming a new film structure with individual perovskite grains encapsulated by amorphous silica layers that are in situ formed at the nanoscale. The silica not only protects perovskite grains from the degradation but alsomore » enhances the charge-carrier dynamics of perovskite films. The underlying mechanism is discussed using a joint experiment-theory approach. Through this in situ grain encapsulation method, PSCs show an efficiency close to 20% with an impressive 97% retention after 1000-h storage under ambient conditions.« less

Monitoring fractional anisotropy in developing rabbit brain using MR diffusion tensor imaging at 3T

NASA Astrophysics Data System (ADS)

Jao, Jo-Chi; Yang, Yu-Ting; Hsiao, Chia-Chi; Chen, Po-Chou

2016-03-01

The aim of this study was to investigate the factional anisotropy (FA) in various regions of developing rabbit brain using magnetic resonance diffusion tensor imaging (MR DTI) at 3 T. A whole-body clinical MR imaging (MRI) scanner with a 15-channel high resolution knee coil was used. An echo-planar-imaging (EPI)-DTI pulse sequence was performed. Five 5 week-old New Zealand white (NZW) rabbits underwent MRI once per week for 24 weeks. After scanning, FA maps were obtained. ROIs (regions of interests) in the frontal lobe, parietal & temporal lobe, and occipital lobe were measured. FA changes with time were evaluated with a linear regression analysis. The results show that the FA values in all lobes of the brain increased linearly with age. The ranking of FA values was FA(frontal lobe) < FA(parietal & temporal lobe) > FA(occipital lobe). There was significant difference (p < 0.05) among these lobes. FA values are associated with the nerve development and brain functions. The FA change rate could be a biomarker to monitor the brain development. Understanding the FA values of various lobes during development could provide helpful information to diagnosis the abnormal syndrome earlier and have a better treatment and prognosis. This study established a brain MR-DTI protocol for rabbits to investigate the brain anatomy during development using clinical MRI. This technique can be further applied to the pre-clinical diagnosis, treatment, prognosis and follow-up of brain lesions.

Enantioselective analysis of chiral anteiso fatty acids in the polar and neutral lipids of food.

PubMed

Hauff, Simone; Hottinger, Georg; Vetter, Walter

2010-04-01

Anteiso fatty acids (aFA) are substituted with a methyl group on the antepenultimate carbon of the straight acyl chain. This feature leads to a stereogenic center. The 12-methyltetradecanoic acid (a15:0) and the 14-methylhexadecanoic acid (a17:0) are the most common aFA found in food, although they occur only in very small quantities. In this study we used gas chromatography in combination with a chiral stationary phase to determine the enantiomeric distribution of both a15:0 and a17:0 in the neutral and polar lipids of aquatic food samples and cheese. The best suited column was selected out of four custom-made combinations of heptakis(6-O-tert-butyldimethylsilyl-2,3-di-O-methyl)-beta-cyclodextrin (beta-TBDM) with different amount and polarity of an achiral polysiloxane. After separation of polar and neutral lipids of the food samples by solid phase extraction, fatty acid methyl esters were prepared and the fatty acid methyl esters were fractionated by reversed phase high performance liquid chromatography. Measurements of fractions high in aFA by enantioselective GC/MS in the selected ion monitoring mode verified the dominance of the (S)-enantiomers of a15:0 and a17:0 in both lipid fractions. However (R)-enantiomers were detectable in all samples. The relative proportion of the (R)-enantiomers was up to fivefold higher in the polar lipids than in the neutral lipids. The higher proportions in the polar lipids indicate that microorganisms might be involved in the formation of (R)-aFA.

Effects of body and organ size on absorbed dose: there is no standard patient. [Radiation dose distribution in patients following radionuclide administration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poston, J.W.

1976-01-01

The problem of estimating the absorbed dose to organs and tissues of the human body due to the presence of a radiopharmaceutical in one or more organs is discussed. Complications are introduced by the fact that the body is not homogeneous and in many cases the organ shapes are not regular. Publications of the MIRD Committee have provided a direct means of estimating the absorbed dose (or absorbed fraction) for a number of radioisotopes. These estimates are based on Monte Carlo calculations for monoenergetic photons distributed uniformly in organs of an adult phantom. The medical physicist finds that his patientmore » does not resemble the adult phantom. In addition, the absorbed fractions for the adult are not reasonable values for the child. This paper examines how these absorbed fraction estimates apply to a nonstandard patient. (auth)« less

Diffusion Tensor Fractional Anisotropy in the Superior Longitudinal Fasciculus Correlates with Functional Independence Measure Cognition Scores in Patients with Cerebral Infarction.

PubMed

Koyama, Tetsuo; Domen, Kazuhisa

2017-08-01

This study aimed to determine the relationship between fiber tract degeneration measured by diffusion-tensor imaging (DTI) and outcome of patients after cerebral infarction. Fractional anisotropy (FA) maps were generated by DTI in patients 14-21 days after the first infarction and were analyzed by tract-based spatial statistics (TBSS). Mean FA values within the corticospinal tract (CST) and the superior longitudinal fasciculus (SLF) were extracted from individual TBSS data. Relationships between FA ratios (rFAs, lesioned to non-lesioned hemisphere) and outcomes assessed by Brunnstrom stage (BRS) and Functional Independence Measure (FIM) motor and cognition scores were examined using Spearman's rank correlation test. Forty patients (21 left and 19 right hemisphere lesions) were entered into an analytical database. BRS ranged from 1 to 6 (median, 5) for shoulder, elbow, or forearm; from 2 to 6 (median, 4.5) for hand or finger; and from 3 to 6 (median, 5) for lower extremity. FIM motor ranged from 51 to 91 (median, 79.5), and FIM cognition ranged from 16 to 35 (median, 29). rFA values in the CST ranged from .692 to 1.053 (median, .933), and those in the SLF ranged from .778 to 1.076 (median, .965). Mann-Whitney U test (P <.05) revealed no significant differences between the left and the right hemisphere lesion groups. Individual rFA values in the CST correlated with BRS scores (r = .585-0.654), whereas those in the SLF correlated with FIM cognition scores (r = .409, P <.05). DTI-FA values in the SLF and CST may be useful for outcome prediction of cognitive function and extremity function, respectively. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

N-stearoylethanolamine restores pancreas lipid composition in obesity-induced insulin resistant rats.

PubMed

Onopchenko, Oleksandra V; Kosiakova, Galina V; Oz, Murat; Klimashevsky, Vitaliy M; Gula, Nadiya M

2015-01-01

This study investigates the protective effect of N-stearoylethanolamine (NSE), a bioactive N-acylethanolamine , on the lipid profile distribution in the pancreas of obesity-induced insulin resistant (IR) rats fed with prolonged high fat diet (58% of fat for 6 months). The phospholipid composition was determined using 2D thin-layer chromatography. The level of individual phospholipids was estimated by measuring inorganic phosphorus content. The fatty acid (FA) composition and cholesterol level were investigated by gas-liquid chromatography. Compared to controls, plasma levels of triglycerides and insulin were significantly increased in IR rats. The pancreas lipid composition indicated a significant reduction of the free cholesterol level and some phospholipids such as phosphatidylcholine (PtdCho), phosphatidylethanolamine (PtdEtn), phosphatidylinositol (PtdIns), phosphatidylserine (PtdSer) compared to controls. Moreover, the FA composition of pancreas showed a significant redistribution of the main FA (18:1n-9, 18:2n-6, 18:3n-6 and 20:4n-6) levels between phospholipid, free FA, triglyceride fractions under IR conditions that was accompanied by a change in the estimated activities of Δ9-, Δ6-, Δ5-desaturase. Administration of N-stearoylethanolamine (NSE, 50 mg/kg daily per os for 2 weeks) IR rats triggered an increase in the content of free cholesterol, PtdCho and normalization of PtdEtn, PtdSer level. Furthermore, the NSE modulated the activity of desaturases, thus influenced FA composition and restored the FA ratios in the lipid fractions. These NSE-induced changes were associated with a normalization of plasma triglyceride content, considerable decrease of insulin and index HOMA-IR level in rats under IR conditions.

Left hemisphere fractional anisotropy increase in noise-induced tinnitus: a diffusion tensor imaging (DTI) study of white matter tracts in the brain.

PubMed

Benson, Randall R; Gattu, Ramtilak; Cacace, Anthony T

2014-03-01

Diffusion tensor imaging (DTI) is a contemporary neuroimaging modality used to study connectivity patterns and microstructure of white matter tracts in the brain. The use of DTI in the study of tinnitus is a relatively unexplored methodology with no studies focusing specifically on tinnitus induced by noise exposure. In this investigation, participants were two groups of adults matched for etiology, age, and degree of peripheral hearing loss, but differed by the presence or absence (+/-) of tinnitus. It is assumed that matching individuals on the basis of peripheral hearing loss, allows for differentiating changes in white matter microstructure due to hearing loss from changes due to the effects of chronic tinnitus. Alterations in white matter tracts, using the fractional anisotropy (FA) metric, which measures directional diffusion of water, were quantified using tract-based spatial statistics (TBSS) with additional details provided by in vivo probabilistic tractography. Our results indicate that 10 voxel clusters differentiated the two groups, including 9 with higher FA in the group with tinnitus. A decrease in FA was found for a single cluster in the group with tinnitus. However, seven of the 9 clusters with higher FA were in left hemisphere thalamic, frontal, and parietal white matter. These foci were localized to the anterior thalamic radiations and the inferior and superior longitudinal fasciculi. The two right-sided clusters with increased FA were located in the inferior fronto-occipital fasciculus and superior longitudinal fasciculus. The only decrease in FA for the tinnitus-positive group was found in the superior longitudinal fasciculus of the left parietal lobe. Copyright © 2013 Elsevier B.V. All rights reserved.

Subconcussive Head Impact Exposure and White Matter Tract Changes over a Single Season of Youth Football.

PubMed

Bahrami, Naeim; Sharma, Dev; Rosenthal, Scott; Davenport, Elizabeth M; Urban, Jillian E; Wagner, Benjamin; Jung, Youngkyoo; Vaughan, Christopher G; Gioia, Gerard A; Stitzel, Joel D; Whitlow, Christopher T; Maldjian, Joseph A

2016-12-01

Purpose To examine the effects of subconcussive impacts resulting from a single season of youth (age range, 8-13 years) football on changes in specific white matter (WM) tracts as detected with diffusion-tensor imaging in the absence of clinically diagnosed concussions. Materials and Methods Head impact data were recorded by using the Head Impact Telemetry system and quantified as the combined-probability risk-weighted cumulative exposure (RWE CP ). Twenty-five male participants were evaluated for seasonal fractional anisotropy (FA) changes in specific WM tracts: the inferior fronto-occipital fasciculus (IFOF), inferior longitudinal fasciculus, and superior longitudinal fasciculus (SLF). Fiber tracts were segmented into a central core and two fiber terminals. The relationship between seasonal FA change in the whole fiber, central core, and the fiber terminals with RWE CP was also investigated. Linear regression analysis was conducted to determine the association between RWE CP and change in fiber tract FA during the season. Results There were statistically significant linear relationships between RWE cp and decreased FA in the whole (R 2 = 0.433; P = .003), core (R 2 = 0.3649; P = .007), and terminals (R 2 = 0.5666; P < .001) of left IFOF. A trend toward statistical significance (P = .08) in right SLF was observed. A statistically significant correlation between decrease in FA of the right SLF terminal and RWE CP was also observed (R 2 = 0.2893; P = .028). Conclusion This study found a statistically significant relationship between head impact exposure and change of FA fractional anisotropy value of whole, core, and terminals of left IFOF and right SLF's terminals where WM and gray matter intersect, in the absence of a clinically diagnosed concussion. © RSNA, 2016.

DISSOLVED ORGANIC MATTER AND METALS: EFFECTS OF PH ON PARTITIONING

EPA Science Inventory

Eighteen Dutch soils were extracted in aqueous solutions at varying pH. Extracts were analyzed for Cd, Cu, Ni, Pb, and Zn by ICP-AES. Extract dissolved organic carbon (DOC) was fractionated into three operationally defined fractions: hydrophilic acids (Hyd), fulvic acids (FA), an...

Permeability-diffusivity modeling vs. fractional anisotropy on white matter integrity assessment and application in schizophrenia.

PubMed

Kochunov, P; Chiappelli, J; Hong, L E

2013-01-01

Diffusion tensor imaging (DTI) assumes a single pool of anisotropically diffusing water to calculate fractional anisotropy (FA) and is commonly used to ascertain white matter (WM) deficits in schizophrenia. At higher b-values, diffusion-signal decay becomes bi-exponential, suggesting the presence of two, unrestricted and restricted, water pools. Theoretical work suggests that semi-permeable cellular membrane rather than the presence of two physical compartments is the cause. The permeability-diffusivity (PD) parameters measured from bi-exponential modeling may offer advantages, over traditional DTI-FA, in identifying WM deficits in schizophrenia. Imaging was performed in N = 26/26 patients/controls (age = 20-61 years, average age = 40.5 ± 12.6). Imaging consisted of fifteen b-shells: b = 250-3800 s/mm(2) with 30 directions/shell, covering seven slices of mid-sagittal corpus callosum (CC) at 1.7 × 1.7 × 4.6 mm. 64-direction DTI was also collected. Permeability-diffusivity-index (PDI), the ratio of restricted to unrestricted apparent diffusion coefficients, and the fraction of unrestricted compartment (Mu) were calculated for CC and cingulate gray matter (GM). FA values for CC were calculated using tract-based-spatial-statistics. Patients had significantly reduced PDI in CC (p ≅ 10(- 4)) and cingulate GM (p = 0.002), while differences in CC FA were modest (p ≅ .03). There was no group-related difference in Mu. Additional theoretical-modeling analysis suggested that reduced PDI in patients may be caused by reduced cross-membrane water molecule exchanges. PDI measurements for cerebral WM and GM yielded more robust patient-control differences than DTI-FA. Theoretical work offers an explanation that patient-control PDI differences should implicate abnormal active membrane permeability. This would implicate abnormal activities in ion-channels that use water as substrate for ion exchange, in cerebral tissues of schizophrenia patients.

Interactive effects of dietary palm oil concentration and water temperature on lipid digestibility in rainbow trout, Oncorhynchus mykiss.

PubMed

Ng, Wing-Keong; Campbell, Patrick J; Dick, James R; Bell, J Gordon

2003-10-01

An experiment was conducted to evaluate the interactive effects of dietary crude palm oil (CPO) concentration and water temperature on lipid and FA digestibility in rainbow trout. Four isolipidic diets with 0, 5, 10, or 20% (w/w) CPO, at the expense of fish oil, were formulated and fed to groups of trout maintained at water temperatures of 7, 10, or 15 degrees C. The apparent digestibility (AD) of the FA, measured using yttrium oxide as an inert marker, decreased with increasing chain length and increased with increasing unsaturation within each temperature regimen irrespective of CPO level fed to the fish. PUFA of the n-3 series were preferentially absorbed compared to n-6 PUFA in all diet and temperature treatments. Except for a few minor FA, a significant (P < 0.05) interaction between diet and temperature effects on FA digestibility was found. Increasing dietary levels of CPO lead to significant reductions in the AD of saturates and, to a lesser extent, also of the other FA. Lowering water temperature reduced total saturated FA digestibility in trout regardless of CPO level. Based on the lipid class composition of trout feces, this reduction in AD of saturates was due in part to the increasing resistance of dietary TAG to digestion. Increasing CPO level and decreasing water temperature significantly increased TAG content in trout fecal lipids, with saturates constituting more than 60% of the FA composition. Total monoene and PUFA digestibilities were not significantly affected by water temperature in fish fed up to 10% CPO in their diet. The potential impact of reduced lipid and FA digestibility in cold-water fish fed diets supplemented with high levels of CPO on fish growth performance requires further research.

Quantifying folic acid-functionalized multi-walled carbon nanotubes bound to colorectal cancer cells for improved photothermal ablation

NASA Astrophysics Data System (ADS)

Graham, Elizabeth G.; MacNeill, Christopher M.; Levi-Polyachenko, Nicole H.

2013-05-01

Peritoneal metastases of colorectal cancer are a significant challenge in the field of medicine today due to poor results of systemic chemotherapy caused by the poor diffusion of drugs across the blood-peritoneal barrier. Multi-walled carbon nanotubes (MWNTs) are a biocompatible nanomaterial that strongly absorb near-infrared light to locally heat the surrounding area. Colorectal cancer is known to overexpress folate receptor; therefore, folic acid (FA) was covalently attached to MWNTs to target colorectal cancer cells. Results from real-time polymerase chain reaction found differing expression of folate receptor-α in two colorectal cancer cell lines, RKO and HCT116, as well as a healthy epithelial cell line, HEPM. A spectrophotometric method was developed to quantify the mass of MWNTs bound to cells, and it was determined that FA-targeted MWNTs resulted in a 400-500 % greater affinity for colorectal cancer cells than untargeted MWNTs. The non-cancerous cell line, HEPM, had higher non-specific MWNT interaction and similar MWNT-FA affinity. Stimulated by 1,064 nm light, FA-functionalized MWNTs caused a 50-60 % decrease in colorectal cancer cell viability compared to a 4-10 % decrease caused by untargeted MWNTs. Our results indicate that FA-targeted MWNTs may increase the therapeutic index of MWNT-induced photothermal therapy.

Effect of fulvic acid surface coatings on plutonium sorption and desorption kinetics on goethite

DOE PAGES

Tinnacher, Ruth M.; Begg, James D.; Mason, Harris; ...

2015-01-21

The rates and extent of plutonium (Pu) sorption and desorption onto mineral surfaces are important parameters for predicting Pu mobility in subsurface environments. The presence of natural organic matter, such as fulvic acid (FA), may influence these parameters. We investigated the effects of FA on Pu(IV) sorption/desorption onto goethite in two scenarios: when FA was (1) initially present in solution or (2) found as organic coatings on the mineral surface. A low pH was used to maximize FA coatings on goethite. Experiments were combined with kinetic modeling and speciation calculations to interpret variations in Pu sorption rates in the presencemore » of FA. Our results indicate that FA can change the rates and extent of Pu sorption onto goethite at pH 4. Differences in the kinetics of Pu sorption were observed as a function of the concentration and initial form of FA. The fraction of desorbed Pu decreased in the presence of FA, indicating that organic matter can stabilize sorbed Pu on goethite. These results suggest that ternary Pu–FA–mineral complexes could enhance colloid-facilitated Pu transport. In conclusion, more representative natural conditions need to be investigated to quantify the relevance of these findings.« less

Elevated left and reduced right orbitomedial prefrontal fractional anisotropy in adults with bipolar disorder revealed by tract-based spatial statistics.

PubMed

Versace, Amelia; Almeida, Jorge R C; Hassel, Stefanie; Walsh, Nicholas D; Novelli, Massimiliano; Klein, Crystal R; Kupfer, David J; Phillips, Mary L

2008-09-01

Diffusion tensor imaging (DTI) studies in adults with bipolar disorder (BD) indicate altered white matter (WM) in the orbitomedial prefrontal cortex (OMPFC), potentially underlying abnormal prefrontal corticolimbic connectivity and mood dysregulation in BD. To use tract-based spatial statistics (TBSS) to examine WM skeleton (ie, the most compact whole-brain WM) in subjects with BD vs healthy control subjects. Cross-sectional, case-control, whole-brain DTI using TBSS. University research institute. Fifty-six individuals, 31 having a DSM-IV diagnosis of BD type I (mean age, 35.9 years [age range, 24-52 years]) and 25 controls (mean age, 29.5 years [age range, 19-52 years]). Fractional anisotropy (FA) longitudinal and radial diffusivities in subjects with BD vs controls (covarying for age) and their relationships with clinical and demographic variables. Subjects with BD vs controls had significantly greater FA (t > 3.0, P 3.0, P

Fuel blends: Enhanced electro-oxidation of formic acid in its blend with methanol at platinum nanoparticles modified glassy carbon electrodes

NASA Astrophysics Data System (ADS)

El-Deab, Mohamed S.; El-Nagar, Gumaa A.; Mohammad, Ahmad M.; El-Anadouli, Bahgat E.

2015-07-01

The current study addresses, for the first time, the enhanced direct electro-oxidation of formic acid (FA) at platinum-nanoparticles modified glassy carbon (nano-Pt/GC) electrode in the presence of methanol (MeOH) as a blending fuel. This enhancement is probed by: (i) the increase of the direct oxidation current of FA to CO2 (Ipd, dehydrogenation pathway), (ii) suppressing the dehydration pathway (Ipind, producing the poisoning intermediate CO) and (iii) a favorable negative shift of the onset potential of Ipd with increasing the mole fraction of MeOH in the blend. Furthermore, the charge of the direct FA oxidation in 0.3 M FA + 0.3 M MeOH blend is by 14 and 21times higher than that observed for 0.3 M FA and 0.3 M MeOH, respectively. MeOH is believed to adsorb at the Pt surface sites and thus disfavor the "non-faradaic" dissociation of FA (which produces the poisoning CO intermediate), i.e., MeOH induces a high CO tolerance of the Pt catalyst. The enhanced oxidation activity indicates that FA/MeOH blend is a promising fuel system.

Assessment of volatile compounds, neutral and polar lipid fatty acids of four beef muscles from USDA Choice and Select graded carcasses and their relationships with consumer palatability scores and intramuscular fat content.

PubMed

Hunt, M R; Legako, J F; Dinh, T T N; Garmyn, A J; O'Quinn, T G; Corbin, C H; Rathmann, R J; Brooks, J C; Miller, M F

2016-06-01

Fatty acids (FA) in neutral and polar lipids (NL and PL) and volatile compounds were determined in Gluteus medius (GM), Longissimus lumborum (LL), Serratus ventralis (SV), and Semimembranosus (SM) muscles from upper 2/3 USDA Choice and Select quality grades (QG). Concentrations of NL FA (mg/g) were influenced by intramuscular fat (IMF) content being greater in upper 2/3 Choice compared with Select. The SV contained greater concentrations of NL FA; meanwhile, the SM contained the lowest quantities of NL FA. Percentages (g/100g of total FA) of NL SFA and MUFA were increased in beef with greater IMF content. Concentrations and percentages of PL FA had muscle specific differences between QG. Volatile compounds were primarily affected by muscle. Increases in SFA and MUFA were related with consumer liking, regardless of lipid fraction. Overall the influence of QG on SFA and MUFA was muscle specific. Therefore, each muscle may require specific considerations when considering FA, volatile compounds, and ultimately consumer liking. Copyright © 2016 Elsevier Ltd. All rights reserved.

Accelerated White Matter Aging in Schizophrenia: Role of White Matter Blood Perfusion

PubMed Central

Chiappelli, Joshua; McMahon, Robert; Muellerklein, Florian; Wijtenburg, S. Andrea; White, Michael G.; Rowland, Laura M.; Hong, L. Elliot

2014-01-01

Elevated rate of age-related decline in white matter integrity, indexed by fractional anisotropy (FA) from diffusion tensor imaging, was reported in patients with schizophrenia. Its etiology is unknown. We hypothesized that a decline of blood perfusion to the white matter may underlie the accelerated age-related reduction in FA in schizophrenia. Resting white matter perfusion and FA were collected using pseudo-continuous arterial spin labeling and high-angular-resolution diffusion tensor imaging, respectively, in 50 schizophrenia patients and 70 controls (age=18-63 years). Main outcome measures were the diagnosis-by-age interaction on whole-brain white matter perfusion, and FA. Significant age-related decline in brain white matter perfusion and FA were present in both groups. Age-by-diagnosis interaction was significant for FA (p<0.001) but not white matter perfusion. Age-by-diagnosis interaction for FA values remained significant even after accounting for age-related decline in perfusion. Therefore, we replicated the finding of an increased rate of age-related white matter FA decline in schizophrenia, and observed a significant age-related decline in white matter blood perfusion, although the latter did not contribute to the accelerated age-related decline in FA. The results suggest that factors other than reduced perfusion account for the accelerated age-related decline in white matter integrity in schizophrenia. PMID:24680326

Shelf life determinants and enzyme activities of pearl millet: a comparison of changes in stored flour of hybrids, CMS lines, inbreds and composites.

PubMed

Goyal, Preeti; Chugh, L K

2017-09-01

Shelf life of pearl millet flour is very short because of rapid development of rancidity. This investigation was carried out in view of generating breeding material for development of low rancid pearl millet hybrids/varieties. Flour of twenty-one genotypes; seven hybrids, seven CMS lines, five inbreds and two composites stored in covered aluminium boxes at 37 °C for 30 days along with respective fresh flour was analysed for shelf life indicators/determinants. Crude fat content and fat acidity (FA) of fresh flour of the genotypes varied from 3.8 to 7.2% and 11 to 75 mg KOH/100 g d.m., respectively. FA in stored flour ranged between 180 and 330 mg KOH/100 g d.m. After storage, magnitude of decrease in pH of water extract of flour of the genotypes varied from 0.15 to 0.44. Activity of peroxidase (POX) varied from 378 to 588 units in control flour and irrespective of the genotypes decreased upon storage. Increase in FA (difference between FA of fresh and stored flour) rather total build up of FA was positively associated with crude fat content (r = 0.440*) indicated comparatively more prominent role of lipolytic enzymes. Chemical changes taking place in water soluble fraction of flour were independent of fat content as no correlation was discerned between fat content and decrease in pH. Among the hybrids, HHB 197 had lowest crude fat content (4.7%), lowest total build up FA (212 mg KOH/100 g d.m.), slowest increase in FA (191 mg KOH/100 g d.m.), least decrease in pH (0.31) of water soluble fraction flour during storage and lowest activity of POX in fresh flour (377 units/g d.m). Among all the tested CMS lines, inbreds and composites, HBL 11 showed pattern of quantitative changes in FA, pH and POX activity similar to the hybrid HHB 197 and was identified a promising inbred for developing low-rancid pearl millet variety or hybrid.

Estimation of absorbed fraction to the anterior nose from inhaled beta emitters

NASA Astrophysics Data System (ADS)

Moussa, Hanna Moussa

2000-08-01

The main purpose of this research is to introduce a new and more realistic geometry for the anterior nose region (ET1) as an alternative to the one provided in ICRP Publication 66. For a more accurate estimation of electron absorbed fraction (AF) to the nuclei of basal cells in the ET 1 region, the proposed new geometry (frustum of a cone) replaces the cylinder geometry, which was used in ICRP 66. Since the electron absorbed fraction (AF) data in ICRP 66 are calculated based on the nose size for an adult Caucasian male, a second purpose of this research is to investigate how the nose size (different ethnic groups) and nose tissue composition (male, female and adolescent), affects the electron absorbed fraction values. The third aim of this research is to develop a Monte Carlo program to estimate the electron energies that emerge from the surface of spherical dust particles. Given that electrons can be located anywhere between the center and the surface of the sphere, we vary the sphere radius from 0.5 to 50 μm and investigate the effects of self-absorption on the emitted electron energies and absorbed fraction.

Fanconi anemia protein, FANCG, is a phosphoprotein and is upregulated with FANCA after TNF-alpha treatment.

PubMed

Futaki, M; Watanabe, S; Kajigaya, S; Liu, J M

2001-02-23

Fanconi anemia (FA) is a genetic syndrome characterized by bone marrow failure, birth defects, and a predisposition to malignancy. At this time, six FA genes have been identified, and several gene products have been found to interact in a protein complex. FA cells appear to overexpress the proinflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha). We therefore examined the effects of TNF-alpha on the regulation of FA complementation group proteins, FANCG and FANCA. We found that treatment with TNF-alpha induced FANCG protein expression. FANCA was induced concurrently with FANCG, and the FANCA/FANCG complex was increased in the nucleus following TNF-alpha treatment. Inactivation of inhibitory kappa B kinase-2 modulated the expression of FANCG. We also found that both nuclear and cytoplasmic FANCG fractions were phosphorylated. These results show that FANCG is a phosphoprotein and suggest that the cellular accumulation of FA proteins is subject to regulation by TNF-alpha signaling.

Dietary Effects on Stable Carbon Isotope Composition of Fatty Acids in Polar and Neutral Fractions of Intramuscular Fat of Lambs.

PubMed

van Leeuwen, Katryna A; Camin, Federica; Jerónimo, Eliana; Vasta, Valentina; Prenzler, Paul D; Ryan, Danielle; Bessa, Rui J B

2017-11-01

In this study we measured δ 13 C values of the main fatty acids (FA) present in neutral and polar intramuscular lipids of meat samples from 24 lambs, fed with four different diets supplemented with sunflower and linseed oil and the tanniferous shrub Cistus ladanifer L. The objective was to understand if the increase in intramuscular fat observed in lambs fed simultaneously C. ladanifer and oil was explained mostly by incorporation of diet derived FA or by increased de novo FA synthesis. De novo FA synthesis was evaluated by 13 C enrichment (‰) of 16:0 in intramuscular lipids compared to bulk diet or compared to dietary 16:0. Oil reduced 13 C enrichment of 16:0 in muscle lipid but had no effect when the diet included C. ladanifer (P value <0.01). Thus, dietary C. ladanifer blocked the inhibitory effects of lipid supplementation on de novo FA synthesis.

Neurocognitive and neuroimaging correlates of pediatric traumatic brain injury: A diffusion tensor imaging (DTI) study

PubMed Central

Wozniak, Jeffrey R.; Krach, Linda; Ward, Erin; Mueller, Bryon A.; Muetzel, Ryan; Schnoebelen, Sarah; Kiragu, Andrew; Lim, Kelvin O.

2010-01-01

This study examined the sensitivity of diffusion tensor imaging (DTI) to microstructural white matter (WM) damage in mild and moderate pediatric traumatic brain injury (TBI). Fourteen children with TBI and 14 controls ages 10–18 had DTI scans and neurocognitive evaluations at 6–12 months post-injury. Groups did not differ in intelligence, but children with TBI showed slower processing speed, working memory and executive deficits, and greater behavioral dysregulation. The TBI group had lower fractional anisotropy (FA) in three WM regions: inferior frontal, superior frontal, and supracallosal. There were no group differences in corpus callosum. FA in the frontal and supracallosal regions was correlated with executive functioning. Supracallosal FA was also correlated with motor speed. Behavior ratings showed correlations with supracallosal FA. Parent-reported executive deficits were inversely correlated with FA. Results suggest that DTI measures are sensitive to long-term WM changes and associated with cognitive functioning following pediatric TBI. PMID:17446039

Saturated and trans fatty acids content in unpackaged traditional bakery products in Santa Fe city, Argentina: nutrition labeling relevance.

PubMed

Negro, Emilse; González, Marcela Aída; Bernal, Claudio Adrián; Williner, María Rosa

2017-08-01

Studies have reported the relationship between the excessive intake of saturated fatty acids (SFA) and trans fatty acids (t-FA) and an increased risk of cardiovascular disease. Since 2006, the MERCOSUR countries require that the mandatory nutrition labeling should include information not only about the content of SFA but also about the content of t-FA. This does not apply to fractionated products at the point of retail, such as bakery products. This paper aimed to determine the total fat content and the fatty acid profile in unpackaged traditional bakery products (breads, biscuits and pastries) in Santa Fe, Argentina. Except for French bread, the contribution of t-FA and SFA to the total FA consumption from baked products was high. On the other hand, due to the high variability detected in the FA composition of bakery products between bakeries, it would be necessary to implement regulations making nutrition labeling mandatory in these products.

Altering cortical connectivity: Remediation-induced changes in the white matter of poor readers

PubMed Central

Keller, Timothy A.; Just, Marcel Adam

2009-01-01

SUMMARY Neuroimaging studies using diffusion tensor imaging (DTI) have revealed regions of cerebral white matter with decreased microstructural organization (lower fractional anisotropy or FA) among poor readers. We examined whether 100 hours of intensive remedial instruction affected the white matter of 8–10-year-old poor readers. Prior to instruction, poor readers had significantly lower FA than good readers in a region of the left anterior centrum semiovale. The instruction resulted in a change in white matter (significantly increased FA), and in the very same region. The FA increase was correlated with a decrease in radial diffusivity (but not with a change in axial diffusivity), suggesting that myelination had increased. Furthermore, the FA increase was correlated with improvement in phonological decoding ability, clarifying the cognitive locus of the effect. The results demonstrate for the first time the capability of a behavioral intervention to bring about a positive change in cortico-cortical white matter tracts. PMID:20005820

Occurrence of pesticide non extractable residues in physical and chemical fractions from two natural soils.

NASA Astrophysics Data System (ADS)

Andreou, K.; Jones, K.; Semple, K.

2009-04-01

Distribution of pesticide non extractable residues resulted from the incubation of two natural soils with each of the isoproturon, diazinon and cypermethrin pesticide was assessed in this study. Pesticide non extractable residues distribution in soil physical and chemical fractions is known to ultimately affect their fate. This study aimed to address the fate and behaviour of the non extractable residues in the context of their association with soil physical and chemical fractions with varying properties and characteristics. Non extractable residues were formed from incubation of each pesticide in the two natural soils over a period of 24 months. Soils containing the non extractable residues were fractionated into three solid phase fractions using a physical fractionation procedure as follows: Sediment (SED, >20 μm), (II) Microaggregate (MA, 20-2 μm) and (III) Colloid phase (COL, 2-0.05 μm). Each soil fraction was then fractionated into organic carbon chemical fractionations as follows: Fulvic acid (FA), Humic acid (HA) and Humin (HM). Significant amount of the pesticides was lost during the incubation period. Enrichment factors for the organic carbon and the 14C-pesticide residues were higher in the MA and COL fraction rather than the SED fraction. Greater association and enrichment of the fulvic acid fraction of the organic carbon in the soil was observed. Non extractable residues at the FA fraction showed to diminish while in the HA fraction were increased with decreasing the fraction size. An appreciable amount of non extractable residues were located in the HM fraction but this was less than the amount recovered in the humic substances. Long term fate of pesticide non extractable residues in the soil structural components is important in order to assess any risk associated with them.

pH-Dependent solubility and permeability criteria for provisional biopharmaceutics classification (BCS and BDDCS) in early drug discovery.

PubMed

Varma, Manthena V; Gardner, Iain; Steyn, Stefanus J; Nkansah, Paul; Rotter, Charles J; Whitney-Pickett, Carrie; Zhang, Hui; Di, Li; Cram, Michael; Fenner, Katherine S; El-Kattan, Ayman F

2012-05-07

The Biopharmaceutics Classification System (BCS) is a scientific framework that provides a basis for predicting the oral absorption of drugs. These concepts have been extended in the Biopharmaceutics Drug Disposition Classification System (BDDCS) to explain the potential mechanism of drug clearance and understand the effects of uptake and efflux transporters on absorption, distribution, metabolism, and elimination. The objective of present work is to establish criteria for provisional biopharmaceutics classification using pH-dependent passive permeability and aqueous solubility data generated from high throughput screening methodologies in drug discovery settings. The apparent permeability across monolayers of clonal cell line of Madin-Darby canine kidney cells, selected for low endogenous efflux transporter expression, was measured for a set of 105 drugs, with known BCS and BDDCS class. The permeability at apical pH 6.5 for acidic drugs and at pH 7.4 for nonacidic drugs showed a good correlation with the fraction absorbed in human (Fa). Receiver operating characteristic (ROC) curve analysis was utilized to define the permeability class boundary. At permeability ≥ 5 × 10(-6) cm/s, the accuracy of predicting Fa of ≥ 0.90 was 87%. Also, this cutoff showed more than 80% sensitivity and specificity in predicting the literature permeability classes (BCS), and the metabolism classes (BDDCS). The equilibrium solubility of a subset of 49 drugs was measured in pH 1.2 medium, pH 6.5 phosphate buffer, and in FaSSIF medium (pH 6.5). Although dose was not considered, good concordance of the measured solubility with BCS and BDDCS solubility class was achieved, when solubility at pH 1.2 was used for acidic compounds and FaSSIF solubility was used for basic, neutral, and zwitterionic compounds. Using a cutoff of 200 μg/mL, the data set suggested a 93% sensitivity and 86% specificity in predicting both the BCS and BDDCS solubility classes. In conclusion, this study identified pH-dependent permeability and solubility criteria that can be used to assign provisional biopharmaceutics class at early stage of the drug discovery process. Additionally, such a classification system will enable discovery scientists to assess the potential limiting factors to oral absorption, as well as help predict the drug disposition mechanisms and potential drug-drug interactions.

Adverse effects of metallic artifacts on voxel-wise analysis and tract-based spatial statistics in diffusion tensor imaging.

PubMed

Goto, Masami; Abe, Osamu; Hata, Junichi; Fukunaga, Issei; Shimoji, Keigo; Kunimatsu, Akira; Gomi, Tsutomu

2017-02-01

Background Diffusion tensor imaging (DTI) is a magnetic resonance imaging (MRI) technique that reflects the Brownian motion of water molecules constrained within brain tissue. Fractional anisotropy (FA) is one of the most commonly measured DTI parameters, and can be applied to quantitative analysis of white matter as tract-based spatial statistics (TBSS) and voxel-wise analysis. Purpose To show an association between metallic implants and the results of statistical analysis (voxel-wise group comparison and TBSS) for fractional anisotropy (FA) mapping, in DTI of healthy adults. Material and Methods Sixteen healthy volunteers were scanned with 3-Tesla MRI. A magnetic keeper type of dental implant was used as the metallic implant. DTI was acquired three times in each participant: (i) without a magnetic keeper (FAnon1); (ii) with a magnetic keeper (FAimp); and (iii) without a magnetic keeper (FAnon2) as reproducibility of FAnon1. Group comparisons with paired t-test were performed as FAnon1 vs. FAnon2, and as FAnon1 vs. FAimp. Results Regions of significantly reduced and increased local FA values were revealed by voxel-wise group comparison analysis (a P value of less than 0.05, corrected with family-wise error), but not by TBSS. Conclusion Metallic implants existing outside the field of view produce artifacts that affect the statistical analysis (voxel-wise group comparisons) for FA mapping. When statistical analysis for FA mapping is conducted by researchers, it is important to pay attention to any dental implants present in the mouths of the participants.

Primary granulomatous angiitis of the central nervous system: findings of magnetic resonance spectroscopy and fractional anisotropy in diffusion tensor imaging prior to surgery. Case report.

PubMed

Beppu, Takaaki; Inoue, Takashi; Nishimoto, Hideaki; Nakamura, Shinichi; Nakazato, Yoichi; Ogasawara, Kuniaki; Ogawa, Akira

2007-10-01

Primary granulomatous angiitis of the central nervous system (CNS) is extremely rare. Its preoperative diagnosis is difficult as the condition displays nonspecific features on routine neuroimaging investigations. In this paper, the authors report findings of magnetic resonance (MR) spectroscopy and fractional anisotropy (FA) with diffusion tensor MR imaging in a case of granulomatous angiitis of the CNS. A 30-year-old man presented with morning headaches and grand mal seizures. An MR image revealed a mass resembling glioblastoma in the right temporal lobe. Magnetic resonance spectroscopy showed a high choline/creatine (Cho/Cr) ratio indicative of a malignant neoplasm, accompanied by a slight elevation of glutamate and glutamine. The FA value was very low, which is inconsistent with malignant glioma. The mass was totally removed surgically. Histologically, the peripheral lesion of the mass consisted of a rough accumulation of fat granule cells, infiltration of inflammatory cells, and distribution of capillary vessels. Some vessels within the lesion were replaced by granulomas. The histological diagnosis was granulomatous angiitis of the CNS. The MIB-1-positive rate of the granuloma was approximately 5%. Both MR spectroscopy and FA were unable to accurately diagnose granulomatous angiitis of the CNS prior to surgery; however, elevated Cho/Cr and glutamate and glutamine shown by MR spectroscopy may indicate the moderate proliferation potential of the granuloma and the inflammatory process, respectively, in this condition. Although the low FA value in the present case enabled the authors to rule out a diagnosis of glioblastoma, FA values in inflammatory lesions require careful interpretation.

DISSOLVED ORGANIC MATTER AND METALS: EFFECTS OF PH ON PARTITIONING NATURAL ORGANIC MATTER IN SOILS AND WATER

EPA Science Inventory

Eighteen Dutch soils were extracted in aqueous solutions at varying pH. Extracts were analyzed for Cd, Cu, Ni, Pb, and Zn by ICP-AES. Extract dissolved organic carbon (DOC) was fractionated into three operationally defined fractions: hydrophilic acids (Hyd), fulvic acids (FA), an...

Exploring JLA supernova data with improved flux-averaging technique

NASA Astrophysics Data System (ADS)

Wang, Shuang; Wen, Sixiang; Li, Miao

2017-03-01

In this work, we explore the cosmological consequences of the ``Joint Light-curve Analysis'' (JLA) supernova (SN) data by using an improved flux-averaging (FA) technique, in which only the type Ia supernovae (SNe Ia) at high redshift are flux-averaged. Adopting the criterion of figure of Merit (FoM) and considering six dark energy (DE) parameterizations, we search the best FA recipe that gives the tightest DE constraints in the (zcut, Δ z) plane, where zcut and Δ z are redshift cut-off and redshift interval of FA, respectively. Then, based on the best FA recipe obtained, we discuss the impacts of varying zcut and varying Δ z, revisit the evolution of SN color luminosity parameter β, and study the effects of adopting different FA recipe on parameter estimation. We find that: (1) The best FA recipe is (zcut = 0.6, Δ z=0.06), which is insensitive to a specific DE parameterization. (2) Flux-averaging JLA samples at zcut >= 0.4 will yield tighter DE constraints than the case without using FA. (3) Using FA can significantly reduce the redshift-evolution of β. (4) The best FA recipe favors a larger fractional matter density Ωm. In summary, we present an alternative method of dealing with JLA data, which can reduce the systematic uncertainties of SNe Ia and give the tighter DE constraints at the same time. Our method will be useful in the use of SNe Ia data for precision cosmology.

An image-based skeletal model for the ICRP reference adult male—specific absorbed fractions for neutron-generated recoil protons

NASA Astrophysics Data System (ADS)

Jokisch, D. W.; Rajon, D. A.; Bahadori, A. A.; Bolch, W. E.

2011-11-01

Recoiling hydrogen nuclei are a principle mechanism for energy deposition from incident neutrons. For neutrons incident on the human skeleton, the small sizes of two contrasting media (trabecular bone and marrow) present unique problems due to a lack of charged-particle (protons) equilibrium. Specific absorbed fractions have been computed for protons originating in the human skeletal tissues for use in computing neutron dose response functions. The proton specific absorbed fractions were computed using a pathlength-based range-energy calculation in trabecular skeletal samples of a 40 year old male cadaver.

Regional white matter development in very preterm infants: perinatal predictors and early developmental outcomes.

PubMed

Rogers, Cynthia E; Smyser, Tara; Smyser, Christopher D; Shimony, Joshua; Inder, Terrie E; Neil, Jeffrey J

2016-01-01

Preterm infants are at risk for white matter (WM) injury and adverse neurodevelopmental outcomes. Serial diffusion tensor magnetic resonance imaging data were obtained from very preterm infants (N = 78) born <30 wk gestation imaged up to four times from 26-42 wk postmenstrual age. Slopes were calculated for fractional anisotropy (FA) and mean diffusivity (MD) within regions of interest for infants with ≥2 scans (N = 50). Sixty-five children underwent neurodevelopmental testing at 2 y of age. FA slope for the posterior limb of the internal capsule was greater than other regions. The anterior limb of the internal capsule (ALIC), corpus callosum, and optic radiations demonstrated greater FA slope with increasing gestational age. Infants with patent ductus arteriosus had lower FA slope in the ALIC. MD slope was lower with prolonged ventilation or lack of antenatal steroids. At 2 y of age, lower motor scores were associated with lower FA in the left but higher FA in the right inferior temporal lobe at term-equivalent age. Better social-emotional competence was related to lower FA in the left cingulum bundle. This study demonstrates regional variability in the susceptibility/sensitivity of WM maturation to perinatal factors and relationships between altered diffusion measures and developmental outcomes in preterm neonates.

Effect of natural aquatic humic substances on the photodegradation of estrone.

PubMed

Silva, Carla Patrícia; Lima, Diana L D; Groth, Milena B; Otero, Marta; Esteves, Valdemar I

2016-02-01

Photodegradation of estrone (E1) was investigated under simulated solar radiation in absence and presence of the different fractions of humic substances (HS), namely humic acids (HA), fulvic acids (FA) and XAD-4 fraction. The pseudo-first order photodegradation rate constants increased from 0.1137 h(-1), in ultrapure (MQ) water, to 0.1774, 0.1943 and 0.3109 h(-1), in presence of HA, FA and XAD-4, respectively. Half-life time decreased from 6.10 h in MQ water to 3.91, 3.57 and 2.23 h in presence of HA, FA and XAD-4, respectively. These results evidence the relevant photosensitizing effect of XAD-4 fraction of HS on the degradation of E1, which, to the best of our knowledge have never been studied. Photodegradation studies were also conducted in organic matter-rich environmental aquatic matrices, namely fresh, estuarine and waste water. After 2 h, photodegradation achieved values ranged between 35.6 and 57.1% in natural water samples, compared with 26.4% in ultrapure water. The higher photodegradation occurred in an estuarine water sample, known to be rich in XAD-4 fraction and poor in HA, indicating that not only the presence of organic matter, but also its type, are determinant in the E1 photodegradation rate. Finally, the use of sodium azide as singlet oxygen ((1)O2) scavenger during the phototransformation of E1 in ultrapure and in two wastewater samples allowed to conclude that (1)O2 has an important role in the E1 photodegradation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Carbon and Hydrogen Isotope Fractionation in Lipid Biosynthesis of Piezophilic Bacteria - Implications for Studying Microbial Metabolism and Carbon Cycle in Deep Biosphere

NASA Astrophysics Data System (ADS)

Fang, J.; Dasgupta, S.; Zhang, L.; Li, J.; Kato, C.; Bartlett, D.

2012-12-01

Piezophiles are pressure-loving microorganisms, which reproduce preferentially or exclusively at pressures greater than atmospheric pressure. In this study, we examined stable carbon and hydrogen isotope fractionation in fatty acid biosynthesis of a piezophilic bacterium Moritella japonica DSK1. The bacterium was grown to stationary phase at hydrstatic pressures of 0.1, 10, 20, and 50 MPa (mega-passcal) in media prepared using sterilized natural seawater supplied with glucose as the sole carbon source. Bacterial cell biomass and individual fatty acids exhibited consistent pressure-dependent carbon and hydrogen isotope fractionations relative to substrates. Average carbon isotope fractionation (delta(FA-glucose)) at high pressures was much higher than that for surface bacteria: -15.7, -15.3, and -18.3‰ at 10, 20, and 50 MPa, respectively. For deltaD, fatty acids are more depleted in D relative to glucose than to water. Monounsaturated fatty acids are more depleted in D than corresponding saturated fatty acids by as much as 36‰. Polyunsaturated fatty acids are most depleted in D. For example, DHA (22:6omega3) has the most negative hydrogen isotope ratio (-170.91‰) (delta(FA-glucose) = -199, delta(FA-water) = -176). The observed isotope effects can be ascribed to the kinetics of enzymatic reactions that are affected by hydrostatic pressure and to operating of two independent lipid biosynthetic pathways of the piezophilic bacteria. Given that most of the biosphere lives under high pressures, our results have important important implications for studying microbial metabolism and carbon cycle in the deep biosphere.

Motor network efficiency and disability in multiple sclerosis

PubMed Central

Yaldizli, Özgür; Sethi, Varun; Muhlert, Nils; Liu, Zheng; Samson, Rebecca S.; Altmann, Daniel R.; Ron, Maria A.; Wheeler-Kingshott, Claudia A.M.; Miller, David H.; Chard, Declan T.

2015-01-01

Objective: To develop a composite MRI-based measure of motor network integrity, and determine if it explains disability better than conventional MRI measures in patients with multiple sclerosis (MS). Methods: Tract density imaging and constrained spherical deconvolution tractography were used to identify motor network connections in 22 controls. Fractional anisotropy (FA), magnetization transfer ratio (MTR), and normalized volume were computed in each tract in 71 people with relapse onset MS. Principal component analysis was used to distill the FA, MTR, and tract volume data into a single metric for each tract, which in turn was used to compute a composite measure of motor network efficiency (composite NE) using graph theory. Associations were investigated between the Expanded Disability Status Scale (EDSS) and the following MRI measures: composite motor NE, NE calculated using FA alone, FA averaged in the combined motor network tracts, brain T2 lesion volume, brain parenchymal fraction, normal-appearing white matter MTR, and cervical cord cross-sectional area. Results: In univariable analysis, composite motor NE explained 58% of the variation in EDSS in the whole MS group, more than twice that of the other MRI measures investigated. In a multivariable regression model, only composite NE and disease duration were independently associated with EDSS. Conclusions: A composite MRI measure of motor NE was able to predict disability substantially better than conventional non-network-based MRI measures. PMID:26320199

Diffusion tensor MRI tractography reveals increased fractional anisotropy (FA) in arcuate fasciculus following music-cued motor training.

PubMed

Moore, Emma; Schaefer, Rebecca S; Bastin, Mark E; Roberts, Neil; Overy, Katie

2017-08-01

Auditory cues are frequently used to support movement learning and rehabilitation, but the neural basis of this behavioural effect is not yet clear. We investigated the microstructural neuroplasticity effects of adding musical cues to a motor learning task. We hypothesised that music-cued, left-handed motor training would increase fractional anisotropy (FA) in the contralateral arcuate fasciculus, a fibre tract connecting auditory, pre-motor and motor regions. Thirty right-handed participants were assigned to a motor learning condition either with (Music Group) or without (Control Group) musical cues. Participants completed 20minutes of training three times per week over four weeks. Diffusion tensor MRI and probabilistic neighbourhood tractography identified FA, axial (AD) and radial (RD) diffusivity before and after training. Results revealed that FA increased significantly in the right arcuate fasciculus of the Music group only, as hypothesised, with trends for AD to increase and RD to decrease, a pattern of results consistent with activity-dependent increases in myelination. No significant changes were found in the left ipsilateral arcuate fasciculus of either group. This is the first evidence that adding musical cues to movement learning can induce rapid microstructural change in white matter pathways in adults, with potential implications for therapeutic clinical practice. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Diffusion Tensor Imaging of Heterotopia: Changes of Fractional Anisotropy during Radial Migration of Neurons

PubMed Central

Kim, Jinna

2010-01-01

Purpose Diffusion tensor imaging provides better understanding of pathophysiology of congenital anomalies, involving central nervous system. This study was aimed to specify the pathogenetic mechanism of heterotopia, proved by diffusion tensor imaging, and establish new findings of heterotopia on fractional anisotropy maps. Materials and Methods Diffusion-weighted imaging data from 11 patients (M : F = 7 : 4, aged from 1 to 22 years, mean = 12.3 years) who visited the epilepsy clinic and received a routine seizure protocol MRI exam were retrospectively analyzed. Fractional anisotropy (FA) maps were generated from diffusion tensor imaging of 11 patients with heterotopia. Regions of interests (ROI) were placed in cerebral cortex, heterotopic gray matter and deep gray matter, including putamen. ANOVA analysis was performed for comparison of different gray matter tissues. Results Heterotopic gray matter showed signal intensities similar to normal gray matter on T1 and T2 weighted MRI. The measured FA of heterotopic gray matter was higher than that of cortical gray matter (0.236 ± 0.011 vs. 0.169 ± 0.015, p < 0.01, one way ANOVA), and slightly lower than that of deep gray matter (0.236 ± 0.011 vs. 0.259 ± 0.016, p < 0.01). Conclusion Increased FA of heterotopic gray matter suggests arrested neuron during radial migration and provides better understanding of neurodevelopment. PMID:20499428

Diffusion-weighted imaging and diffusion tensor imaging of asymptomatic lumbar disc herniation.

PubMed

Sakai, Toshinori; Miyagi, Ryo; Yamabe, Eiko; Fujinaga, Yasunari; N Bhatia, Nitin; Yoshioka, Hiroshi

2014-01-01

Diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) were performed on a healthy 31-year-old man with asymptomatic lumbar disc herniation. Although the left S1 nerve root was obviously entrapped by a herniated mass, neither DWI nor DTI showed any significant findings for the nerve root. Decreased apparent diffusion coefficient (ADC) values and increased fractional anisotropy (FA) values were found. These results are contrary to those in previously published studies of symptomatic patients, in which a combination of increased ADC and decreased FA seem to have a relationship with nerve injury and subsequent symptoms, such as leg pain or palsy. Our results seen in an asymptomatic subject suggest that the compressed nerve with no injury, such as edema, demyelination, or persistent axonal injury, may be indicated by a combination of decreased ADC and increased FA. ADC and FA could therefore be potential tools to elucidate the pathomechanism of radiculopathy.

Diffusion tensor imaging with quantitative evaluation and fiber tractography of lumbar nerve roots in sciatica.

PubMed

Shi, Yin; Zong, Min; Xu, Xiaoquan; Zou, Yuefen; Feng, Yang; Liu, Wei; Wang, Chuanbing; Wang, Dehang

2015-04-01

To quantitatively evaluate nerve roots by measuring fractional anisotropy (FA) values in healthy volunteers and sciatica patients, visualize nerve roots by tractography, and compare the diagnostic efficacy between conventional magnetic resonance imaging (MRI) and DTI. Seventy-five sciatica patients and thirty-six healthy volunteers underwent MR imaging using DTI. FA values for L5-S1 lumbar nerve roots were calculated at three levels from DTI images. Tractography was performed on L3-S1 nerve roots. ROC analysis was performed for FA values. The lumbar nerve roots were visualized and FA values were calculated in all subjects. FA values decreased in compressed nerve roots and declined from proximal to distal along the compressed nerve tracts. Mean FA values were more sensitive and specific than MR imaging for differentiating compressed nerve roots, especially in the far lateral zone at distal nerves. DTI can quantitatively evaluate compressed nerve roots, and DTT enables visualization of abnormal nerve tracts, providing vivid anatomic information and localization of probable nerve compression. DTI has great potential utility for evaluating lumbar nerve compression in sciatica. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

A bone marrow toxicity model for 223Ra alpha-emitter radiopharmaceutical therapy

NASA Astrophysics Data System (ADS)

Hobbs, Robert F.; Song, Hong; Watchman, Christopher J.; Bolch, Wesley E.; Aksnes, Anne-Kirsti; Ramdahl, Thomas; Flux, Glenn D.; Sgouros, George

2012-05-01

Ra-223, an α-particle emitting bone-seeking radionuclide, has recently been used in clinical trials for osseous metastases of prostate cancer. We investigated the relationship between absorbed fraction-based red marrow dosimetry and cell level-dosimetry using a model that accounts for the expected localization of this agent relative to marrow cavity architecture. We show that cell level-based dosimetry is essential to understanding potential marrow toxicity. The GEANT4 software package was used to create simple spheres representing marrow cavities. Ra-223 was positioned on the trabecular bone surface or in the endosteal layer and simulated for decay, along with the descendants. The interior of the sphere was divided into cell-size voxels and the energy was collected in each voxel and interpreted as dose cell histograms. The average absorbed dose values and absorbed fractions were also calculated in order to compare those results with previously published values. The absorbed dose was predominantly deposited near the trabecular surface. The dose cell histogram results were used to plot the percentage of cells that received a potentially toxic absorbed dose (2 or 4 Gy) as a function of the average absorbed dose over the marrow cavity. The results show (1) a heterogeneous distribution of cellular absorbed dose, strongly dependent on the position of the cell within the marrow cavity; and (2) that increasing the average marrow cavity absorbed dose, or equivalently, increasing the administered activity resulted in only a small increase in potential marrow toxicity (i.e. the number of cells receiving more than 4 or 2 Gy), for a range of average marrow cavity absorbed doses from 1 to 20 Gy. The results from the trabecular model differ markedly from a standard absorbed fraction method while presenting comparable average dose values. These suggest that increasing the amount of radioactivity may not substantially increase the risk of toxicity, a result unavailable to the absorbed fraction method of dose calculation.

FT-IR and C-13 NMR analysis of soil humic fractions from a long term cropping systems study

USDA-ARS?s Scientific Manuscript database

Increased knowledge of humic fractions is important due to its involvement in many soil ecosystem processes. Soil humic acid (HA) and fulvic acid (FA) from a nine-year agroecosystem study with different tillage, cropping system, and N source treatments were characterized using FT-IR andsolid-state ...

RfpA, RfpB, and RfpC are the Master Control Elements of Far-Red Light Photoacclimation (FaRLiP)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Chi; Gan, Fei; Shen, Gaozhong

Terrestrial cyanobacteria often occur in niches that are strongly enriched in far-red light (FRL; λ > 700 nm). Some cyanobacteria exhibit a complex and extensive photoacclimation response, known as FRL photoacclimation (FaRLiP). During the FaRLiP response, specialized paralogous proteins replace 17 core subunits of the three major photosynthetic complexes: Photosystem (PS) I, PS II, and the phycobilisome. Additionally, the cells synthesize both chlorophyll (Chl) f and Chl d. Using biparental mating from Escherichia coli, we constructed null mutants of three genes, rfpA, rfpB, and rfpC, in the cyanobacteria Chlorogloeopsis fritschii PCC 9212 and Chroococcidiopsis thermalis PCC 7203. The resulting mutantsmore » were no longer able to modify their photosynthetic apparatus to absorb FRL, were no longer able to synthesize Chl f, inappropriately synthesized Chl d in white light, and were unable to transcribe genes of the FaRLiP gene cluster. We conclude that RfpA, RfpB, and RfpC constitute a FRL-activated signal transduction cascade that is the master control switch for the FaRLiP response. FRL is proposed to activate (or inactivate) the histidine kinase activity of RfpA, which leads to formation of the active state of RfpB, the key response regulator and transcription activator. RfpC may act as a phosphate shuttle between RfpA and RfpB. Our results show that reverse genetics via conjugation will be a powerful approach in detailed studies of the FaRLiP response.« less

Diffusion Tensor Imaging in Chronic Inflammatory Demyelinating Polyneuropathy: Diagnostic Accuracy and Correlation With Electrophysiology.

PubMed

Kronlage, Moritz; Pitarokoili, Kalliopi; Schwarz, Daniel; Godel, Tim; Heiland, Sabine; Yoon, Min-Suk; Bendszus, Martin; Bäumer, Philipp

2017-11-01

The aims of this study were to assess diagnostic accuracy of diffusion tensor imaging (DTI) in chronic inflammatory demyelinating polyneuropathy (CIDP), to correlate DTI with electrophysiological parameters, and to evaluate whether radial diffusivity (RD) and axial diffusivity (AD) might serve as specific biomarkers of demyelinating and axonal pathology. This prospective study was approved by the institutional ethics committee, and written informed consent was obtained from all participants. Magnetic resonance neurography of upper and lower extremity nerves (median, ulnar, radial, sciatic, tibial) was performed by single-shot DTI sequences at 3.0 T in 18 patients with a diagnosis of CIDP and 18 healthy controls, matched to age and sex. The scalar readout parameters nerve fractional anisotropy (FA), mean diffusivity (MD), RD, and AD were obtained after manual segmentation and postprocessing and compared between patients and controls. Diagnostic accuracy was assessed by receiver operating characteristic analysis, and cutoff values were calculated by maximizing the Youden index. All patients underwent a complementary electroneurography and correlation of electrophysiological markers and DTI parameters was analyzed and described by Pearson and Spearman coefficients. Nerve FA was decreased to a mean of 0.42 ± 0.08 in patients compared with 0.52 ± 0.04 in healthy controls (P < 0.001). This decrease in FA was a result of an increase of RD (P = 0.02), whereas AD did not differ between the two groups. Of all DTI parameters, FA showed best diagnostic accuracy with a receiver operating characteristic area under the curve of 0.90. Optimal cutoff for an average FA of all analyzed nerves was 0.47, yielding a sensitivity of 0.83 and a specificity of 0.94. Fractional anisotropy and RD correlated strongly with electrophysiological markers of demyelination, whereas AD did not correlate with markers of axonal neuropathy. Diffusion tensor imaging yields valid quantitative biomarkers in CIDP and might aid in diagnosis with high diagnostic accuracy. Fractional anisotropy and RD may serve as parameters of myelin sheath integrity, but AD is unable to reflect axonal damage in CIDP.

Different Trophic Tracers Give Different Answers for the Same Bugs - Comparing a Stable Isotope and Fatty Acid Based Analysis of Resource Utilization in a Marine Isopod

NASA Astrophysics Data System (ADS)

Galloway, A. W. E.; Eisenlord, M. E.; Brett, M. T.

2016-02-01

Stable isotope (SI) based mixing models are the most common approach used to infer resource pathways in consumers. However, SI based analyses are often underdetermined, and consumer SI fractionation is usually unknown. The use of fatty acid (FA) tracers in mixing models offers an alternative approach that can resolve the underdetermined constraint. A limitation to both methods is the considerable uncertainty about consumer `trophic modification' (TM) of dietary FA or SI, which occurs as consumers transform dietary resources into tissues. We tested the utility of SI and FA approaches for inferring the diets of the marine benthic isopod (Idotea wosnesenskii) fed various marine macroalgae in controlled feeding trials. Our analyses quantified how the accuracy and precision of Bayesian mixing models was influenced by choice of algorithm (SIAR vs MixSIR), fractionation (assumed or known), and whether the model was under or overdetermined (seven sources and two vs 26 tracers) for cases where isopods were fed an exclusive diet of one of the seven different macroalgae. Using the conventional approach (i.e., 2 SI with assumed TM) resulted in average model outputs, i.e., the contribution from the exclusive resource = 0.20 ± 0.23 (0.00-0.79), mean ± SD (95% credible interval), that only differed slightly from the prior assumption. Using the FA based approach with known TM greatly improved model performance, i.e., the contribution from the exclusive resource = 0.91 ± 0.10 (0.58-0.99). The choice of algorithm only made a difference when fractionation was known and the model was overdetermined (FA approach). In this case SIAR and MixSIR had outputs of 0.86 ± 0.11 (0.48-0.96) and 0.96 ± 0.05 (0.79-1.00), respectively. This analysis shows the choice of dietary tracers and the assumption of consumer trophic modification greatly influence the performance of mixing model dietary reconstructions, and ultimately our understanding of what resources actually support aquatic consumers.

Effects of gradient encoding and number of signal averages on fractional anisotropy and fiber density index in vivo at 1.5 tesla.

PubMed

Widjaja, E; Mahmoodabadi, S Z; Rea, D; Moineddin, R; Vidarsson, L; Nilsson, D

2009-01-01

Tensor estimation can be improved by increasing the number of gradient directions (NGD) or increasing the number of signal averages (NSA), but at a cost of increased scan time. To evaluate the effects of NGD and NSA on fractional anisotropy (FA) and fiber density index (FDI) in vivo. Ten healthy adults were scanned on a 1.5T system using nine different diffusion tensor sequences. Combinations of 7 NGD, 15 NGD, and 25 NGD with 1 NSA, 2 NSA, and 3 NSA were used, with scan times varying from 2 to 18 min. Regions of interest (ROIs) were placed in the internal capsules, middle cerebellar peduncles, and splenium of the corpus callosum, and FA and FDI were calculated. Analysis of variance was used to assess whether there was a difference in FA and FDI of different combinations of NGD and NSA. There was no significant difference in FA of different combinations of NGD and NSA of the ROIs (P>0.005). There was a significant difference in FDI between 7 NGD/1 NSA and 25 NGD/3 NSA in all three ROIs (P<0.005). There were no significant differences in FDI between 15 NGD/3 NSA, 25 NGD/1 NSA, and 25 NGD/2 NSA and 25 NGD/3 NSA in all ROIs (P>0.005). We have not found any significant difference in FA with varying NGD and NSA in vivo in areas with relatively high anisotropy. However, lower NGD resulted in reduced FDI in vivo. With larger NGD, NSA has less influence on FDI. The optimal sequence among the nine sequences tested with the shortest scan time was 25 NGD/1 NSA.

Editor’s Highlight: Lower Fractional Anisotropy in the Globus Pallidus of Asymptomatic Welders, a Marker for Long-Term Welding Exposure

PubMed Central

Lee, Eun-Young; Flynn, Michael R.; Du, Guangwei; Lewis, Mechelle M.; Herring, Amy H.; Van Buren, Eric; Van Buren, Scott; Kong, Lan; Mailman, Richard B.; Huang, Xuemei

2016-01-01

Introduction: Welding fumes contain several metals including manganese (Mn), iron (Fe), and copper (Cu) that at high exposure may co-influence welding-related neurotoxicity. The relationship between brain accumulation of these metals and neuropathology, especially in welders with subclinical exposure levels, is unclear. This study examined the microstructural integrity of basal ganglia (BG) regions in asymptomatic welders using diffusion tensor imaging (DTI). Methods: Subjects with (n = 43) and without (age- and gender-matched controls; n = 31) history of welding were studied. Occupational questionnaires estimated short-term (HrsW; welding hours and E90; cumulative exposure, past 90 days) and long-term (YrsW; total years welding and ELT; cumulative exposure, lifetime) exposure. Whole blood metal levels (Mn, Fe, and Cu) were obtained. Brain MRI pallidal index (PI), R1 (1/T1), and R2* (1/T2*) were measured to estimate Mn and Fe accumulation in BG [caudate, putamen, and globus pallidus (GP)]. DTI was used to assess BG microstructural differences, and related with exposure measurements. Results: When compared with controls, welders had significantly lower fractional anisotropy (FA) in the GP. In welders, GP FA values showed non-linear relationships to YrsW, blood Mn, and PI. GP FA decreased after a critical level of YrsW or Mn was reached, whereas it decreased with increasing PI values until plateauing at the highest PI values. GP FA, however, did not show any relationship with short-term exposure measurements (HrsW, E90), blood Cu and Fe, or R2* values. Conclusion: GP FA captured microstructural changes associated with chronic low-level Mn exposure, and may serve as a biomarker for neurotoxicity in asymptomatic welders. PMID:27466214

Neurite density index is sensitive to age related differences in the developing brain.

PubMed

Genc, Sila; Malpas, Charles B; Holland, Scott K; Beare, Richard; Silk, Timothy J

2017-03-01

White matter development during childhood and adolescence is characterised by increasing white matter coherence and organisation. Commonly used scalar metrics, such as fractional anisotropy (FA), are sensitive to multiple mechanisms of white matter change and therefore unable to distinguish between mechanisms that change during development. We investigate the relationship between age and neurite density index (NDI) from neurite orientation dispersion and density imaging (NODDI), and the age-classification accuracy of NDI compared with FA, in a developmental cohort. Diffusion-weighted imaging data from 72 children and adolescents between the ages of 4-19 was collected (M=10.42, SD=3.99, 36 male). We compared NODDI metrics against conventional DTI metrics (fractional anisotropy [FA], mean diffusivity [MD], axial diffusivity [AD] and radial diffusivity [RD]) in terms of their relationship to age. An ROC analysis was also performed to assess the ability of each metric to classify older and younger participants. NDI exhibited a stronger relationship with age (median R 2 =.60) compared with MD (median R 2 =.39), FA (median R 2 =.27), AD (median R 2 =.14), and RD (median R 2 =.35) in a high proportion of white matter tracts. When participants were divided into an older and younger group, NDI achieved the best classification (median area under the curve [AUC]=.89), followed by MD (median AUC=.81), FA (median AUC=.80), RD (median AUC=.81), and AD (median AUC=.64). Our results demonstrate the sensitivity of NDI to age-related differences in white matter microstructural organisation over development. Importantly, NDI is more sensitive to such developmental changes compared to commonly used DTI metrics. This knowledge provides justification for implementing NODDI metrics in developmental studies. Copyright © 2017 Elsevier Inc. All rights reserved.

Monoglycerides and fatty acids from Ibervillea sonorae root: isolation and hypoglycemic activity.

PubMed

Hernández-Galicia, Erica; Calzada, Fernando; Roman-Ramos, Rubén; Alarcón-Aguilar, Francisco J

2007-03-01

Eleven monoglycerides (MG), 1-monopalmitin (1), glyceryl 1-monomargarate (2), 1-monostearin (3), glyceryl 1-monononadecylate ( 4), glyceryl 1-monoarachidate (5), glyceryl 1-monobehenate (6), glyceryl 1-monotricosanoate (7), glyceryl 1-monotetracosanoate (8), glyceryl 1-monopentacosanoate (9), glyceryl 1-monohexacosanoate (10) and glyceryl 1-monooctacosanoate (11), together with five fatty acids (FA), lauric acid (12), myristic acid (13), pentadecanoic acid (14), palmitic acid (15) and stearic acid (16) were isolated of the root of IBERVILLEA SONORAE Greene (Cucurbitaceae). Their structures were determined by spectroscopic and chemical methods as well as GC-MS analysis. The hypoglycemic activity of the dichloromethane (DCM) extract, of fractions (F1-F10 and SF1-SF5), of monoglycerides (MG) and of fatty acids (FA) mixtures obtained of the root from I. SONORAE was evaluated in normoglycemic and alloxan-induced diabetic mice. The results showed that by intraperitoneal administration the DCM extract (300 mg/kg), F9 (300 mg/kg) and SF1 (150 mg/kg) significantly reduced glucose levels in both models. For fraction SF1, the hypoglycemic activity was more pronounced than that of tolbutamide (150 mg/kg) used as control. However, neither MG (75 mg/kg) nor FA (75 mg/kg) mixtures isolated from SF1 exhibited a significant hypoglycemic effect. However, when MG and FA were combined in equal proportions (75 mg: 75 mg/kg), their effect was comparable to that of SF1. The observed activity for the DCM extract, F9, SF1 and the MG-FA mixture provides additional support for the popular use of this plant in the treatment of diabetes mellitus in Mexican traditional medicine.

The influence of MIR137 on white matter fractional anisotropy and cortical surface area in individuals with familial risk for psychosis.

PubMed

Vogel, Bob O; Lett, Tristram A; Erk, Susanne; Mohnke, Sebastian; Wackerhagen, Carolin; Brandl, Eva J; Romanczuk-Seiferth, Nina; Otto, Kristina; Schweiger, Janina I; Tost, Heike; Nöthen, Markus M; Rietschel, Marcella; Degenhardt, Franziska; Witt, Stephanie H; Meyer-Lindenberg, Andreas; Heinz, Andreas; Walter, Henrik

2018-05-01

The rs1625579 variant near the microRNA-137 (MIR137) gene is one of the best-supported schizophrenia variants in genome-wide association studies (GWAS), and microRNA-137 functionally regulates other GWAS identified schizophrenia risk variants. Schizophrenia patients with the MIR137 rs1625579 risk genotype (homozygous for the schizophrenia risk variant) also have aberrant brain structure. It is unclear if the effect of MIR137 among schizophrenia patients is due to potential epistasis with genetic risk for schizophrenia or other factors of the disorder. Here, we investigated the effect of MIR137 genotype on white matter fractional anisotropy (FA), cortical thickness (CT), and surface area (SA) in a sample comprising healthy control subjects, and individuals with familial risk for psychosis (first-degree relatives of patients with schizophrenia or bipolar disorder; N=426). In voxel-wise analyses of FA, we observed a significant genotype-by-group interaction (P FWE <0.05). The familial risk group with risk genotype had lower FA (P FWE <0.05), but there was no genetic association in controls. In vertex-wise analyses of SA, we also observed a significant genotype-by-group interaction (P FWE <0.05). Relatives with MIR137 risk genotype had lower SA, however the risk genotype was associated with higher SA in the controls (all P FWE <0.05). These results show that MIR137 risk genotype is associated with lower FA in psychosis relatives that is similar to previous imaging-genetics findings in patients with schizophrenia. Furthermore, MIR137 genotype may also be a risk factor in a subclinical population with wide reductions in white matter FA and cortical SA. Copyright © 2017 Elsevier B.V. All rights reserved.

Chemical properties of peat used in balneology

NASA Astrophysics Data System (ADS)

Szajdak, L.; Hładoń, T.

2009-04-01

The physiological activity of peats is observed in human peat-bath therapy and in the promotion of growth in some plants. Balneological peat as an ecologically clean and natural substance is perceived as being more 'human friendly' than synthetic compounds. Poland has a long tradition of using balneological peat for therapeutic purposes. Balneological peat reveals a physical effect by altering temperature and biochemical effects through biologically active substances. It is mainly used for the treatment of rheumatic diseases that are quite common in Poland. Peat represents natural product. Physico-chemical properties of peat in particular surface-active, sorption and ion exchanges, defining their biological function, depend mainly on the chemical composition and molecular structure of humic substances representing the major constituent of organic soil (peat). The carbon of organic matter of peats is composed of 10 to 20% carbohydrates, primarily of microbial origin; 20% nitrogen-containing constituents, such as amino acids and amino sugars; 10 to 20% aliphatic fatty acids, alkanes, etc.; with the rest of carbon being aromatic. For balneology peat should be highly decomposed (preferably H8), natural and clean. The content of humic acids should exceed 20% of dry weight, ash content will be less than 15 15% of dry weight, sulphur content less than 0.3% of dry weight and the amount of water more than 85%. It will not contain harmful bacteria and heavy metals. Humic substances (HS) of peat are known to be macromolecular polydisperse biphyllic systems including both hydrophobic domains (saturated hydrocarbon chains, aromatic structural units) and hydrophilic functional groups, i. e having amphiphilic character. Amphiphilic properties of FA are responsible for their solubility, viscosity, conformation, surfactant-like character and a variety of physicochemical properties of considerable biologically practical significance. The chemical composition of peats depends significantly on the genesis of peatlands and the depth of sampling. The chemical properties of peat fulvic acids (FA) have some genetic peculiarities due to the specific conditions of the process of humification of peat-forming plants in mires. The process of humification in mires takes place in the top-forming layer under amphibious moisture conditions. Substances of microbial origin are water-soluble and can participate in the formation of peat FA to a little extent. So a main source of structural units for the peat HA and FA is suggested to be organic constituents of peat forming plants of various botanical composition. The content of aromatic units in peat FA was shown to depend on the content of lignin in peat-forming plants and also of the aromatization of polysaccharides mainly due to the transformation of cellulose. FA characterized lower than humic acids molecular weight (1000-30,000). FA's are composed of a series of highly oxidized aromatic rings with a large number of side chains. Building blocks are benzene carboxylic acids and phenolic acids. These are held together by hydrogen bonding van der Waals' forces and ionic bonding. FA contains larger concentrations of nitrogen. This fraction also contains a great deal of polysaccharide materials, as well as low molecular fatty acids and cytoplasmic constituents of microorganisms. These compounds are linear, flexible colloids at low concentrations, and spherical colloids at high solution concentrations and low pH values. A more adequate knowledge of the chemical structure of humic materials will assist us in better understanding the physiological effects and also the function of these macromolecules on the health that these materials are know to exert. This improved knowledge provides us better information on chemical structure of humic substances from peats, which are responsible for pharmacotherapeutic, pharmacokinetic and biopharmaceutical effect. This structure of FA creates proper conditions for uptake of nutrient as well as bioavailability of biologically active substances. The solubilization in water by humic materials of organic substances which are otherwise water-insoluble is a matter of considerable interest to chemist deals with the problem of the function of organic matter. There has been considerable evidence that humic substances can "complex" with several biologically active substances and so modify their physiological activity. It has been noteworthy that FA can "fix" high-molecular weight water-insoluble organic compounds and make them water-soluble. FA may so act as a vehicle for the mobilization, transport and immobilization of such substances in physiological conditions. Analysis of HA and FA carried out by several analytical methods revealed that there were no chemical interaction among biologically active substances but that latter was firmly adsorbed, possible by hydrogen-bonding, on the FA surfaces. Amino acids account for the majority of organic N fraction in humic substances. Most of the amino acids in organic matter occur in bound form in the humino-peptides fraction. These amino acids are commonly bound to the central core of FA. These humino-peptides fraction of FA mediate in respiration and act as hydrogen acceptors, thus affecting oxidation-reaction reactions. Thus, what is needed at this time is more fundamental research in order to solve practical pharmacological, pharmacokinetic and biopharmaceutical problem of great significance for human health.

Studies on potential effects of fumaric acid on rumen microbial fermentation, methane production and microbial community.

PubMed

Riede, Susanne; Boguhn, Jeannette; Breves, Gerhard

2013-01-01

The greenhouse gas methane (CH4) contributes substantially to global climate change. As a potential approach to decrease ruminal methanogenesis, the effects of different dosages of fumaric acid (FA) on ruminal microbial metabolism and on the microbial community (archaea, bacteria) were studied using a rumen simulation technique (RUSITEC). FA acts as alternative hydrogen acceptor diverting 2H from methanogenesis of archaea towards propionate formation of bacteria. Three identical trials were conducted with 12 fermentation vessels over a period of 14 days. In each trial, four fermentation vessels were assigned to one of the three treatment groups differing in FA dosage: low fumaric acid (LFA), high fumaric acid (HFA) and without FA (control). FA was continuously infused with the buffer. Grass silage and concentrate served as substrate. FA led to decreases in pH and to higher production rates of total short chain fatty acids (SCFA) mediated by increases in propionate for LFA of 1.69 mmol d(-1) and in propionate and acetate production for HFA of 4.49 and 1.10 mmol d(-1), respectively. Concentrations of NH3-N, microbial crude protein synthesis, their efficiency, degradation of crude nutrients and detergent fibre fraction were unchanged. Total gas and CH4 production were not affected by FA. Effects of FA on structure of microbial community by means of single strand conformation polymorphism (SSCP) analyses could not be detected. Given the observed increase in propionate production and the unaffected CH4 production it can be supposed that the availability of reduction equivalents like 2H was not limited by the addition of FA in this study. It has to be concluded from the present study that the application of FA is not an appropriate approach to decrease the ruminal CH4 production.

Consumer inhalation exposure to formaldehyde from the use of personal care products/cosmetics.

PubMed

Lefebvre, Marc-André; Meuling, Wim J A; Engel, Roel; Coroama, Manuela C; Renner, Gerald; Pape, Wolfgang; Nohynek, Gerhard J

2012-06-01

We measured consumer exposure to formaldehyde (FA) from personal care products (PCP) containing FA-releasing preservatives. Six study subjects applied facial moisturiser, foundation, shower gel, shampoo, deodorant, hair conditioner, hair styling gel or body lotion at the 90th percentile amount of EU PCP consumer use. FA air concentrations were measured in the empty room, in the presence of study subjects prior to PCP use, and for one hour (breathing zone, area monitoring) after PCP use. The mean FA air concentration in the empty bathroom was 1.32 ± 0.67 μg/m³, in the presence of subjects it was 2.33 ± 0.86 μg/m³). Except for body lotion and hair conditioner (6.2 ± 0.1.9 or 4.5 ± 0.1.5 μg/m³, respectively), mean 1-h FA air concentrations after PCP use were similar to background. Peak FA air concentrations, ranging from baseline values (2.2 μg/m³; shower gel) to 11.5 μg/m³ (body lotion), occurred during 0-5 to 5-10 min after PCP use. Despite of exaggerated exposure conditions, FA air levels were a fraction of those considered to be safe (120 μg/m³), occurring in indoor air (22-124 μg/m³) or expired human breath (1.4-87 μg/m³). Overall, our data yielded evidence that inhalation of FA from the use of PCP containing FA-releasers poses no risk to human health. Copyright © 2012 Elsevier Inc. All rights reserved.

Exploring JLA supernova data with improved flux-averaging technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Shuang; Wen, Sixiang; Li, Miao, E-mail: wangshuang@mail.sysu.edu.cn, E-mail: wensx@mail2.sysu.edu.cn, E-mail: limiao9@mail.sysu.edu.cn

2017-03-01

In this work, we explore the cosmological consequences of the ''Joint Light-curve Analysis'' (JLA) supernova (SN) data by using an improved flux-averaging (FA) technique, in which only the type Ia supernovae (SNe Ia) at high redshift are flux-averaged. Adopting the criterion of figure of Merit (FoM) and considering six dark energy (DE) parameterizations, we search the best FA recipe that gives the tightest DE constraints in the ( z {sub cut}, Δ z ) plane, where z {sub cut} and Δ z are redshift cut-off and redshift interval of FA, respectively. Then, based on the best FA recipe obtained, wemore » discuss the impacts of varying z {sub cut} and varying Δ z , revisit the evolution of SN color luminosity parameter β, and study the effects of adopting different FA recipe on parameter estimation. We find that: (1) The best FA recipe is ( z {sub cut} = 0.6, Δ z =0.06), which is insensitive to a specific DE parameterization. (2) Flux-averaging JLA samples at z {sub cut} ≥ 0.4 will yield tighter DE constraints than the case without using FA. (3) Using FA can significantly reduce the redshift-evolution of β. (4) The best FA recipe favors a larger fractional matter density Ω {sub m} . In summary, we present an alternative method of dealing with JLA data, which can reduce the systematic uncertainties of SNe Ia and give the tighter DE constraints at the same time. Our method will be useful in the use of SNe Ia data for precision cosmology.« less

Right hemisphere structures predict poststroke speech fluency.

PubMed

Pani, Ethan; Zheng, Xin; Wang, Jasmine; Norton, Andrea; Schlaug, Gottfried

2016-04-26

We sought to determine via a cross-sectional study the contribution of (1) the right hemisphere's speech-relevant white matter regions and (2) interhemispheric connectivity to speech fluency in the chronic phase of left hemisphere stroke with aphasia. Fractional anisotropy (FA) of white matter regions underlying the right middle temporal gyrus (MTG), precentral gyrus (PreCG), pars opercularis (IFGop) and triangularis (IFGtri) of the inferior frontal gyrus, and the corpus callosum (CC) was correlated with speech fluency measures. A region within the superior parietal lobule (SPL) was examined as a control. FA values of regions that significantly predicted speech measures were compared with FA values from healthy age- and sex-matched controls. FA values for the right MTG, PreCG, and IFGop significantly predicted speech fluency, but FA values of the IFGtri and SPL did not. A multiple regression showed that combining FA of the significant right hemisphere regions with the lesion load of the left arcuate fasciculus-a previously identified biomarker of poststroke speech fluency-provided the best model for predicting speech fluency. FA of CC fibers connecting left and right supplementary motor areas (SMA) was also correlated with speech fluency. FA of the right IFGop and PreCG was significantly higher in patients than controls, while FA of a whole CC region of interest (ROI) and the CC-SMA ROI was significantly lower in patients. Right hemisphere white matter integrity is related to speech fluency measures in patients with chronic aphasia. This may indicate premorbid anatomical variability beneficial for recovery or be the result of poststroke remodeling. © 2016 American Academy of Neurology.

Right hemisphere structures predict poststroke speech fluency

PubMed Central

Pani, Ethan; Zheng, Xin; Wang, Jasmine; Norton, Andrea

2016-01-01

Objective: We sought to determine via a cross-sectional study the contribution of (1) the right hemisphere's speech-relevant white matter regions and (2) interhemispheric connectivity to speech fluency in the chronic phase of left hemisphere stroke with aphasia. Methods: Fractional anisotropy (FA) of white matter regions underlying the right middle temporal gyrus (MTG), precentral gyrus (PreCG), pars opercularis (IFGop) and triangularis (IFGtri) of the inferior frontal gyrus, and the corpus callosum (CC) was correlated with speech fluency measures. A region within the superior parietal lobule (SPL) was examined as a control. FA values of regions that significantly predicted speech measures were compared with FA values from healthy age- and sex-matched controls. Results: FA values for the right MTG, PreCG, and IFGop significantly predicted speech fluency, but FA values of the IFGtri and SPL did not. A multiple regression showed that combining FA of the significant right hemisphere regions with the lesion load of the left arcuate fasciculus—a previously identified biomarker of poststroke speech fluency—provided the best model for predicting speech fluency. FA of CC fibers connecting left and right supplementary motor areas (SMA) was also correlated with speech fluency. FA of the right IFGop and PreCG was significantly higher in patients than controls, while FA of a whole CC region of interest (ROI) and the CC-SMA ROI was significantly lower in patients. Conclusions: Right hemisphere white matter integrity is related to speech fluency measures in patients with chronic aphasia. This may indicate premorbid anatomical variability beneficial for recovery or be the result of poststroke remodeling. PMID:27029627

White Matter Integrity in High-Altitude Pilots Exposed to Hypobaria

PubMed Central

McGuire, Stephen A.; Boone, Goldie R.E.; Sherman, Paul M.; Tate, David F.; Wood, Joe D.; Patel, Beenish; Eskandar, George; Wijtenburg, S. Andrea; Rowland, Laura M.; Clarke, Geoffrey D.; Grogan, Patrick M.; Sladky, John H.; Kochunov, Peter V.

2017-01-01

Introduction Nonhypoxic hypobaric (low atmospheric pressure) occupational exposure, such as experienced by U.S. Air Force U-2 pilots and safety personnel operating inside altitude chambers, is associated with increased subcortical white matter hyperintensity (WMH) burden. The pathophysiological mechanisms underlying this discrete WMH change remain unknown. The objectives of this study were to demonstrate that occupational exposure to nonhypoxic hypobaria is associated with altered white matter integrity as quantified by fractional anisotropy (FA) measured using diffusion tensor imaging and relate these findings to WMH burden and neurocognitive ability. Methods There were 102 U-2 pilots and 114 age- and gender-controlled, health-matched controls who underwent magnetic resonance imaging. All pilots performed neurocognitive assessment. Whole-brain and tract-wise average FA values were compared between pilots and controls, followed by comparison within pilots separated into high and low WMH burden groups. Neurocognitive measurements were used to help interpret group difference in FA values. Results Pilots had significantly lower average FA values than controls (0.489/0.500, respectively). Regionally, pilots had higher FA values in the fronto-occipital tract where FA values positively correlated with visual-spatial performance scores (0.603/0.586, respectively). There was a trend for high burden pilots to have lower FA values than low burden pilots. Discussion Nonhypoxic hypobaric exposure is associated with significantly lower average FA in young, healthy U-2 pilots. This suggests that recurrent hypobaric exposure causes diffuse axonal injury in addition to focal white matter changes. PMID:28323582

Splenium microstructure is related to two dimensions of reading skill.

PubMed

Frye, Richard E; Hasan, Khader; Xue, Lian; Strickland, David; Malmberg, Benjamin; Liederman, Jacqueline; Papanicolaou, Andrew

2008-10-29

Inconsistent differences in the corpus callosum (CC) structure between dyslexic readers (DRs) and typical readers (TRs) have been reported. We examine differences in CC splenium microstructure and the association of splenium microstructure with reading-related skills. Nine DRs and 18 TRs completed a reading skills battery and diffusion tensor imaging. DRs had higher splenium fractional anisotropy (FA) and axial diffusivity (LA) as compared with TRs. Retrieval of orthographic information from the language lexicon was negatively associated with FA and LA within both reading groups. Phonological awareness was positively associated with splenium FA and LA in TRs but not DRs. This study suggests two white matter pathways that may be differentially associated with reading skills in the CC splenium.

Influence of dissolved organic matter and manganese oxides on metal speciation in soil solution: A modelling approach.

PubMed

Schneider, Arnaud R; Ponthieu, Marie; Cancès, Benjamin; Conreux, Alexandra; Morvan, Xavier; Gommeaux, Maxime; Marin, Béatrice; Benedetti, Marc F

2016-06-01

Trace element (TE) speciation modelling in soil solution is controlled by the assumptions made about the soil solution composition. To evaluate this influence, different assumptions using Visual MINTEQ were tested and compared to measurements of free TE concentrations. The soil column Donnan membrane technique (SC-DMT) was used to estimate the free TE (Cd, Cu, Ni, Pb and Zn) concentrations in six acidic soil solutions. A batch technique using DAX-8 resin was used to fractionate the dissolved organic matter (DOM) into four fractions: humic acids (HA), fulvic acids (FA), hydrophilic acids (Hy) and hydrophobic neutral organic matter (HON). To model TE speciation, particular attention was focused on the hydrous manganese oxides (HMO) and the Hy fraction, ligands not considered in most of the TE speciation modelling studies in soil solution. In this work, the model predictions of free ion activities agree with the experimental results. The knowledge of the FA fraction seems to be very useful, especially in the case of high DOM content, for more accurately representing experimental data. Finally, the role of the manganese oxides and of the Hy fraction on TE speciation was identified and, depending on the physicochemical conditions of the soil solution, should be considered in future studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of slaughter age and feeding system on the neutral and polar lipid composition of horse meat.

PubMed

Belaunzaran, X; Lavín, P; Mantecón, A R; Kramer, J K G; Aldai, N

2018-02-01

This study was undertaken to provide a thorough analysis of the neutral lipid (NL) and polar lipid (PL) fractions of horse meat that included the content and distribution of acyl and alkenyl moieties in foals under different rearing conditions. Two groups of crossbred horses were studied; the first group was selected from suckling foals produced under grazing conditions and slaughtered at 4 months of age (n=8), and the second group was selected from concentrate-finished foals and slaughtered at 12 months of age (n=7). There were significant differences related to the age and feeding practices of foals which affected the intramuscular (IM) fat content and the fatty acid (FA) composition of NL and PL fractions. Samples from suckling foals were leaner and provided the highest content of methylation products from the plasmalogenic lipids, and total and n-3 polyunsaturated fatty acid (PUFA). By contrast, the meat from concentrate-finished foals had a higher IM fat level resulting in a greater accumulation of 16:0 and total monounsaturated FAs in the NL fraction, whereas the muscle PL fraction retained a similar FA composition between both groups. Linolenic acid was preferentially deposited in the NL fraction, but linoleic acid and the long-chain n-3 and n-6 PUFAs were incorporated into the PL fraction where they served as cell membrane constituents and in eicosanoid formation.

White matter integrity in major depressive disorder: Implications of childhood trauma, 5-HTTLPR and BDNF polymorphisms.

PubMed

Tatham, Erica L; Ramasubbu, Rajamannar; Gaxiola-Valdez, Ismael; Cortese, Filomeno; Clark, Darren; Goodyear, Bradley; Foster, Jane; Hall, Geoffrey B

2016-07-30

This study examined the impact of childhood neglect, serotonin transporter (5-HTTLPR) and brain derived neurotrophic factor (BDNF) polymorphisms on white matter (WM) integrity in major depressive disorder (MDD) using diffusion tensor imaging (DTI). Fifty-five medication-free MDD patients and 18 controls underwent diffusion tensor imaging scanning, genotyping and completed the Childhood Trauma Questionnaire. Tract based spatial statistics (TBSS) findings revealed reduced fractional anisotropy (FA) in the MDD group in the anterior internal capsule. 5-HTTLPR-S'L' heterozygotes in the MDD group exhibited reduced FA in the internal capsule relative to S'S' and reduced FA in corona radiata compared to L'L'. Probabilistic tractography revealed higher FA in the uncinate fasciculus (UF) for BDNF val/val genotype relative to met-carriers, particularly in individuals with high depression severity. High depression severity and experiences of childhood physical or emotional neglect predicted higher FA in the UF and superior longitudinal fasciculus. Reductions in FA were identified for subgroups of MDD patients who were 5-HTTLPR heterozygotes and BDNF-met carriers. An association between emotional/physical neglect and FA was observed in subjects with high depressive symptoms. Our findings suggest that WM connectivity within frontal and limbic regions are affected by depression and influenced by experiences of neglect and genetic risk factors. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Experimental determination and modeling of arsenic complexation with humic and fulvic acids.

PubMed

Fakour, Hoda; Lin, Tsair-Fuh

2014-08-30

The complexation of humic acid (HA) and fulvic acid (FA) with arsenic (As) in water was studied. Experimental results indicate that arsenic may form complexes with HA and FA with a higher affinity for arsenate than for arsenite. With the presence of iron oxide based adsorbents, binding of arsenic to HA/FA in water was significantly suppressed, probably due to adsorption of As and HA/FA. A two-site ligand binding model, considering only strong and weak site types of binding affinity, was successfully developed to describe the complexation of arsenic on the two natural organic fractions. The model showed that the numbers of weak sites were more than 10 times those of strong sites on both HA and FA for both arsenic species studied. The numbers of both types of binding sites were found to be proportional to the HA concentrations, while the apparent stability constants, defined for describing binding affinity between arsenic and the sites, are independent of the HA concentrations. To the best of our knowledge, this is the first study to characterize the impact of HA concentrations on the applicability of the ligand binding model, and to extrapolate the model to FA. The obtained results may give insights on the complexation of arsenic in HA/FA laden groundwater and on the selection of more effective adsorption-based treatment methods for natural waters. Copyright © 2014 Elsevier B.V. All rights reserved.

Plant growth inhibitors isolated from sugarcane (Saccharum officinarum) straw.

PubMed

Sampietro, Diego Alejandro; Vattuone, Marta Amelia; Isla, María Ines

2006-07-01

Several compounds related with plant defense and pharmacological activities have been isolated from sugarcane. Straw phytotoxins and their possible mechanisms of growth inhibition are largely unknown. A bioassay-guided fractionation of the phytotoxic constituents leachated from a sugarcane straw led to the isolation of trans-ferulic (trans-FA), cis-ferulic (cis-FA), vanillic (VA) and syringic (SA) acids. The straw leachates and their identified constituents significantly inhibited root growth of lettuce and four weeds. VA was more phytotoxic to root elongation than FA and SA. The identified phenolic compounds significantly increased leakage of root cell constituents, inhibited dehydrogenase activity and reduced chlorophyll content in lettuce. VA and FA inhibited mitotic index while SA increased cell division. Additive (VA-FA and FA-SA) and synergistic (VA-SA) interactions on root growth were observed at the response level of EC(25). Although the isolated compounds differed in their relative phytotoxic activities, the observed physiological responses suggest that they have a common mode of action. HPLC analysis indicated that sugarcane straw can potentially release 1.43 (ratio 2:1, trans:cis), 1.14 and 0.14mmolkg(-1) (straw dry weight) of FA, VA and SA, respectively. As phenolic acids are often found spatially concentrated in the top soil layers under plant straws, further studies are needed to establish the impact of these compounds in natural settings.

40 CFR 265.1032 - Standards: Process vents.

Code of Federal Regulations, 2010 CFR

2010-07-01

... owner or operator of a fa-cil-ity with process vents associated with distillation, fractionation, thin-film evaporation, solvent extraction or -air or steam stripping operations man-aging haz-ard-ous wastes...

40 CFR 265.1032 - Standards: Process vents.

Code of Federal Regulations, 2011 CFR

2011-07-01

... owner or operator of a fa-cil-ity with process vents associated with distillation, fractionation, thin-film evaporation, solvent extraction or -air or steam stripping operations man-aging haz-ard-ous wastes...

Concomitant fractional anisotropy and volumetric abnormalities in temporal lobe epilepsy: cross-sectional evidence for progressive neurologic injury.

PubMed

Keller, Simon S; Schoene-Bake, Jan-Christoph; Gerdes, Jan S; Weber, Bernd; Deppe, Michael

2012-01-01

In patients with temporal lobe epilepsy and associated hippocampal sclerosis (TLEhs) there are brain abnormalities extending beyond the presumed epileptogenic zone as revealed separately in conventional magnetic resonance imaging (MRI) and MR diffusion tensor imaging (DTI) studies. However, little is known about the relation between macroscopic atrophy (revealed by volumetric MRI) and microstructural degeneration (inferred by DTI). For 62 patients with unilateral TLEhs and 68 healthy controls, we determined volumes and mean fractional anisotropy (FA) of ipsilateral and contralateral brain structures from T1-weighted and DTI data, respectively. We report significant volume atrophy and FA alterations of temporal lobe, subcortical and callosal regions, which were more diffuse and bilateral in patients with left TLEhs relative to right TLEhs. We observed significant relationships between volume loss and mean FA, particularly of the thalamus and putamen bilaterally. When corrected for age, duration of epilepsy was significantly correlated with FA loss of an anatomically plausible route - including ipsilateral parahippocampal gyrus and temporal lobe white matter, the thalamus bilaterally, and posterior regions of the corpus callosum that contain temporal lobe fibres - that may be suggestive of progressive brain degeneration in response to recurrent seizures. Chronic TLEhs is associated with interrelated DTI-derived and volume-derived brain degenerative abnormalities that are influenced by the duration of the disorder and the side of seizure onset. This work confirms previously contradictory findings by employing multi-modal imaging techniques in parallel in a large sample of patients.

Dissolution of fludrocortisone from phospholipid coprecipitates.

PubMed

Vudathala, G K; Rogers, J A

1992-03-01

The physical properties and dissolution behavior of phospholipid coprecipitates of fludrocortisone acetate (FA) prepared from ethyl acetate, as well as the effect of added polymer, have been determined. The fraction dissolved after 90 min and the initial dissolution rate (IDR) of coprecipitates containing dimyristoyl phosphatidylcholine (DMPC) (4:1, w/w; FA:DMPC) were 77% and 3.5-fold greater than for FA at pH 2.0 and 37 degrees C. The mechanisms of dissolution were similar to those previously established for griseofulvin, but no aging occurred over 4 months at room temperature in a desiccator. The addition of 0.01 mol% of dextran (MW = 2 million) or 0.1 mol% of poly(lactic acid) reduced the fraction of FA dissolved in 90 min by 15% and reduced the IDR by 35%. The addition of poly(vinylpyrrolidone) (PVP) resulted in a minimum of dissolution efficiency at 1 mol% of PVP 10 (MW = 10,000) or PVP 24 (MW = 24,000) and at 0.1 mol% PVP 40 (MW = 40,000). Only PVP 24 influenced the melting point and heat of fusion of the coprecipitates (determined by differential thermal analysis). Coprecipitate dissolution was reasonably described by either second-order or Weibull distribution kinetic models. These results support the application of high drug-containing solid dispersions using phospholipids to increase the dissolution behavior of poorly water-soluble drug solvates and the possibility of modifying drug release by the incorporation of small amounts of polymers.

Profile of Free Fatty Acids and Fractions of Phospholipids, Cholesterol Esters and Triglycerides in Serum of Obese Youth with and without Metabolic Syndrome.

PubMed

Bermúdez-Cardona, Juliana; Velásquez-Rodríguez, Claudia

2016-02-15

The study evaluated the profile of circulating fatty acids (FA) in obese youth with and without metabolic syndrome (MetS) to determine its association with nutritional status, lifestyle and metabolic variables. A cross-sectional study was conducted in 96 young people, divided into three groups: obese with MetS (OBMS), obese (OB) and appropriate weight (AW). FA profiles were quantified by gas chromatography; waist circumference (WC), fat folds, lipid profile, high-sensitivity C-reactive protein, glucose, insulin, the homeostasis model assessment (HOMA index), food intake and physical activity (PA) were assessed. The OBMS group had significantly greater total free fatty acids (FFAs), palmitic-16:0 in triglyceride (TG), palmitoleic-16:1n-7 in TG and phospholipid (PL); in the OB group, these FAs were higher than in the AW group. Dihomo-gamma-linolenic (DHGL-20:3n-6) was higher in the OBMS than the AW in PL and FFAs. Linoleic-18:2n-6 in TG and PL had the lowest proportion in the OBMS group. WC, PA, total FFA, linoleic-18:2n-6 in TG and DHGL-20:3n-6 in FFAs explained 62% of the HOMA value. The OB group presented some higher proportions of FA and biochemical values than the AW group. The OBMS had proportions of some FA in the TG, PL and FFA fractions that correlated with disturbances of MetS.

Occurrence and photodegradation of methylmercury in surface water of Wen-Rui-Tang River network, Wenzhou, China.

PubMed

Pan, Shuihong; Feng, Chuchu; Lin, Jialu; Cheng, Lidong; Wang, Chengjun; Zuo, Yuegang

2017-04-01

The spatial distribution and seasonal variations of methylmercury (MeHg) in Wen-Rui-Tang (WRT) River network were investigated by monitoring the MeHg concentrations in surface water samples collected from 30 sites across the river network over four seasons. Detection frequencies and concentrations of MeHg were generally higher in January, indicating that low sunlight irradiation, wind speed, and temperature conditions might enhance the persistence of MeHg in surface water. The MeHg levels varied with sampling locations, with the highest concentrations being observed in the industrial area especially around wastewater outfall, revealing that the mercury contamination in WRT River mainly comes from the industrial wastewater. Photodegradation of MeHg in WRT River surface water and the effects of natural constituents such as fulvic acid (FA), ferric ions (Fe 3+ ), nitrate (NO 3 - ), and dissolved oxygen on the MeHg photodegradation in aqueous solutions were studied under the simulated sunlight. The experimental data indicated that the indirect photodecomposition of MeHg occurred in WRT River surface water. Photodegradation of MeHg in FA solution was initiated by triplet 3 FA* or MeHg-FA* via electron transfer interaction under light irradiations. The Fe 3+ and NO 3 - can absorb light energy to produce ·OH and enhance the photochemical degradation of MeHg. The MeHg photodecompositions in FA, nitrate, and Fe 3+ solutions were markedly accelerated after removing the dissolved oxygen.

A prospective microstructure imaging study in mixed-martial artists using geometric measures and diffusion tensor imaging: methods and findings

PubMed Central

Mayer, Andrew R.; Ling, Josef M.; Dodd, Andrew B.; Meier, Timothy B.; Hanlon, Faith M.; Klimaj, Stefan D.

2018-01-01

Although diffusion magnetic resonance imaging (dMRI) has been widely used to characterize the effects of repetitive mild traumatic brain injury (rmTBI), to date no studies have investigated how novel geometric models of microstructure relate to more typical diffusion tensor imaging (DTI) sequences. Moreover, few studies have evaluated the sensitivity of different registration pipelines (non-linear, linear and tract-based spatial statistics) for detecting dMRI abnormalities in clinical populations. Results from single-subject analyses in healthy controls (HC) indicated a strong negative relationship between fractional anisotropy (FA) and orientation dispersion index (ODI) in both white and gray matter. Equally important, only moderate relationships existed between all other estimates of free/intracellular water volume fractions and more traditional DTI metrics (FA, mean, axial and radial diffusivity). These findings suggest that geometric measures provide differential information about the cellular microstructure relative to traditional DTI measures. Results also suggest greater sensitivity for non-linear registration pipelines that maximize the anatomical information available in T1-weighted images. Clinically, rmTBI resulted in a pattern of decreased FA and increased ODI, largely overlapping in space, in conjunction with increased intracellular and free water fractions, highlighting the potential role of edema following repeated head trauma. In summary, current results suggest that geometric models of diffusion can provide relatively unique information regarding potential mechanisms of pathology that contribute to long-term neurological damage. PMID:27071950

A prospective microstructure imaging study in mixed-martial artists using geometric measures and diffusion tensor imaging: methods and findings.

PubMed

Mayer, Andrew R; Ling, Josef M; Dodd, Andrew B; Meier, Timothy B; Hanlon, Faith M; Klimaj, Stefan D

2017-06-01

Although diffusion magnetic resonance imaging (dMRI) has been widely used to characterize the effects of repetitive mild traumatic brain injury (rmTBI), to date no studies have investigated how novel geometric models of microstructure relate to more typical diffusion tensor imaging (DTI) sequences. Moreover, few studies have evaluated the sensitivity of different registration pipelines (non-linear, linear and tract-based spatial statistics) for detecting dMRI abnormalities in clinical populations. Results from single-subject analyses in healthy controls (HC) indicated a strong negative relationship between fractional anisotropy (FA) and orientation dispersion index (ODI) in both white and gray matter. Equally important, only moderate relationships existed between all other estimates of free/intracellular water volume fractions and more traditional DTI metrics (FA, mean, axial and radial diffusivity). These findings suggest that geometric measures provide differential information about the cellular microstructure relative to traditional DTI measures. Results also suggest greater sensitivity for non-linear registration pipelines that maximize the anatomical information available in T 1 -weighted images. Clinically, rmTBI resulted in a pattern of decreased FA and increased ODI, largely overlapping in space, in conjunction with increased intracellular and free water fractions, highlighting the potential role of edema following repeated head trauma. In summary, current results suggest that geometric models of diffusion can provide relatively unique information regarding potential mechanisms of pathology that contribute to long-term neurological damage.

White matter disease correlates with lexical retrieval deficits in primary progressive aphasia.

PubMed

Powers, John P; McMillan, Corey T; Brun, Caroline C; Yushkevich, Paul A; Zhang, Hui; Gee, James C; Grossman, Murray

2013-01-01

To relate fractional anisotropy (FA) changes associated with the semantic and logopenic variants of primary progressive aphasia (PPA) to measures of lexical retrieval. We collected neuropsychological testing, volumetric magnetic resonance imaging, and diffusion-weighted imaging on semantic variant PPA (svPPA) (n = 11) and logopenic variant PPA (lvPPA) (n = 13) patients diagnosed using published criteria. We also acquired neuroimaging data on a group of demographically comparable healthy seniors (n = 34). FA was calculated and analyzed using a white matter (WM) tract-specific analysis approach. This approach utilizes anatomically guided data reduction to increase sensitivity and localizes results within canonically defined tracts. We used non-parametric, cluster-based statistical analysis to relate language performance to FA and determine regions of reduced FA in patients. We found widespread FA reductions in WM for both variants of PPA. FA was related to both confrontation naming and category naming fluency performance in left uncinate fasciculus and corpus callosum in svPPA and left superior and inferior longitudinal fasciculi in lvPPA. SvPPA and lvPPA are associated with distinct disruptions of a large-scale network implicated in lexical retrieval, and the WM disease in each phenotype may contribute to language impairments including lexical retrieval.

Effects of organic matter fraction and compositional changes on distribution of cadmium and zinc in long-term polluted paddy soils.

PubMed

Zhou, Tong; Wu, Longhua; Luo, Yongming; Christie, Peter

2018-01-01

Soil particulate organic matter (POM) has rapid turnover and metal enrichment, but the interactions between organic matter (OM) and metals have not been well studied. The present study aimed to investigate changes in the OM concentration and composition of the POM fraction and their corresponding effects on metal distribution and extractability in long-term polluted paddy soils. Soil 2000-53 μm POM size fractions had higher contents of C-H and C=O bonds, C-H/C=O ratios and concentrations of fulvic acid (FA), humic acid (HA), cadmium (Cd) and zinc (Zn) than the bulk soils. Cadmium and Zn stocks in soil POM fractions were 24.5-27.9% and 7.12-16.7%, respectively, and were more readily EDTA-extractable. Compared with the control soil, the 2000-250 μm POM size fractions had higher organic carbon concentrations and C/N ratios in the polluted soils. However, there were no significant differences in the contents in C-H and C=O bonds or C-H/C=O ratios of POM fractions among the control, slightly and highly polluted soils. In accordance with the lower contents of C=O bonds and FA and HA concentrations, the Cd and Zn concentrations in 250-53 μm POM size fractions were lower than those in 2000-250 μm POM size fractions. Enrichment of Cd in POM fractions increased with increasing soil pollution level. These results support the view that changes in the OM concentration and the size and composition of POM fractions play a key role in determining the distribution of Cd and Zn in paddy soils. Copyright © 2017. Published by Elsevier Ltd.

A comprehensive tractography study of patients with bipolar disorder and their unaffected siblings.

PubMed

Sprooten, Emma; Barrett, Jennifer; McKay, D Reese; Knowles, Emma E; Mathias, Samuel R; Winkler, Anderson M; Brumbaugh, Margaret S; Landau, Stefanie; Cyr, Lindsay; Kochunov, Peter; Glahn, David C

2016-10-01

Diffusion tensor imaging studies show reductions in fractional anisotropy (FA) in individuals with bipolar disorder and their unaffected siblings. However, the use of various analysis methods is an important source of between-study heterogeneity. Using tract-based spatial statistics, we previously demonstrated widespread FA reductions in patients and unaffected relatives. To better interpret the neuroanatomical pattern of this previous finding and to assess the influence of methodological heterogeneity, we here applied tractography to the same sample. Diffusion-weighted images were acquired for 96 patients, 69 unaffected siblings and 56 controls. We applied TRACULA, an extension of a global probabilistic tractography algorithm, to automatically segment 18 major fiber tracts. Average FA within each tract and at each cross-section along each tract was compared between groups. Patients had reduced FA compared to healthy controls and their unaffected siblings in general, and in particular in the parietal part of the superior longitudinal fasciculus. In unaffected siblings, FA was nominally reduced compared to controls in the corpus callosum. Point-wise analyses indicated that similar effects were present along extended sections, but with variable effect sizes. Current symptom severity negatively correlated with FA in several fronto-limbic association tracts. The differential sensitivity of analysis techniques likely explains between-study heterogeneity in anatomical localization of FA reductions. The present tractography analysis confirms the presence of overall FA reductions in patients with bipolar disorder, which are most pronounced in the superior longitudinal fasciculus. Unaffected siblings may display similar, albeit more subtle and anatomically restricted FA reductions. Hum Brain Mapp 37:3474-3485, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Disruption of White Matter Integrity in Adult Survivors of Childhood Brain Tumors: Correlates with Long-Term Intellectual Outcomes.

PubMed

King, Tricia Z; Wang, Liya; Mao, Hui

2015-01-01

Although chemotherapy and radiation treatment have contributed to increased survivorship, treatment-induced brain injury has been a concern when examining long-term intellectual outcomes of survivors. Specifically, disruption of brain white matter integrity and its relationship to intellectual outcomes in adult survivors of childhood brain tumors needs to be better understood. Fifty-four participants underwent diffusion tensor imaging in addition to structural MRI and an intelligence test (IQ). Voxel-wise group comparisons of fractional anisotropy calculated from DTI data were performed using Tract Based Spatial Statistics (TBSS) on 27 survivors (14 treated with radiation with and without chemotherapy and 13 treated without radiation treatment on average over 13 years since diagnosis) and 27 healthy comparison participants. Whole brain white matter fractional anisotropy (FA) differences were explored between each group. The relationships between IQ and FA in the regions where statistically lower FA values were found in survivors were examined, as well as the role of cumulative neurological factors. The group of survivors treated with radiation with and without chemotherapy had lower IQ relative to the group of survivors without radiation treatment and the healthy comparison group. TBSS identified white matter regions with significantly different mean fractional anisotropy between the three different groups. A lower level of white matter integrity was found in the radiation with or without chemotherapy treated group compared to the group without radiation treatment and also the healthy control group. The group without radiation treatment had a lower mean FA relative to healthy controls. The white matter disruption of the radiation with or without chemotherapy treated survivors was positively correlated with IQ and cumulative neurological factors. Lower long-term intellectual outcomes of childhood brain tumor survivors are associated with lower white matter integrity. Radiation and adjunct chemotherapy treatment may play a role in greater white matter disruption. The relationships between white matter integrity and IQ, as well as cumulative neurological risk factors exist in young adult survivors of childhood brain tumors.

Patterns of white matter damage are non-random and associated with cognitive function in secondary progressive multiple sclerosis.

PubMed

Meijer, K A; Cercignani, M; Muhlert, N; Sethi, V; Chard, D; Geurts, J J G; Ciccarelli, O

2016-01-01

In multiple sclerosis (MS), white matter damage is thought to contribute to cognitive dysfunction, which is especially prominent in secondary progressive MS (SPMS). While studies in healthy subjects have revealed patterns of correlated fractional anisotropy (FA) across white matter tracts, little is known about the underlying patterns of white matter damage in MS. In the present study, we aimed to map the SPMS-related covariance patterns of microstructural white matter changes, and investigated whether or not these patterns were associated with cognitive dysfunction. Diffusion MRI was acquired from 30 SPMS patients and 32 healthy controls (HC). A tensor model was fitted and FA maps were processed using tract-based spatial statistics (TBSS) in order to obtain a skeletonised map for each subject. The skeletonised FA maps of patients only were decomposed into 18 spatially independent components (ICs) using independent component analysis. Comprehensive cognitive assessment was conducted to evaluate five cognitive domains. Correlations between cognitive performance and (1) severity of FA abnormalities of the extracted ICs (i.e. z-scores relative to FA values of HC) and (2) IC load (i.e. FA covariance of a particular IC) were examined. SPMS patients showed lower FA values of all examined patterns of correlated FA (i.e. spatially independent components) than HC (p < 0.01). Tracts visually assigned to the supratentorial commissural class were most severely damaged (z = - 3.54; p < 0.001). Reduced FA was significantly correlated with reduced IC load (i.e. FA covariance) (r = 0.441; p < 0.05). Lower mean FA and component load of the supratentorial projection tracts and limbic association tracts classes were associated with worse cognitive function, including executive function, working memory and verbal memory. Despite the presence of white matter damage, it was possible to reveal patterns of FA covariance across SPMS patients. This could indicate that white matter tracts belonging to the same cluster, and thus with similar characteristics, tend to follow similar trends during neurodegeneration. Furthermore, these underlying FA patterns might help to explain cognitive dysfunction in SPMS.

Heterochronicity of white matter development and aging explains regional patient control differences in schizophrenia.

PubMed

Kochunov, Peter; Ganjgahi, Habib; Winkler, Anderson; Kelly, Sinead; Shukla, Dinesh K; Du, Xiaoming; Jahanshad, Neda; Rowland, Laura; Sampath, Hemalatha; Patel, Binish; O'Donnell, Patricio; Xie, Zhiyong; Paciga, Sara A; Schubert, Christian R; Chen, Jian; Zhang, Guohao; Thompson, Paul M; Nichols, Thomas E; Hong, L Elliot

2016-12-01

Altered brain connectivity is implicated in the development and clinical burden of schizophrenia. Relative to matched controls, schizophrenia patients show (1) a global and regional reduction in the integrity of the brain's white matter (WM), assessed using diffusion tensor imaging (DTI) fractional anisotropy (FA), and (2) accelerated age-related decline in FA values. In the largest mega-analysis to date, we tested if differences in the trajectories of WM tract development influenced patient-control differences in FA. We also assessed if specific tracts showed exacerbated decline with aging. Three cohorts of schizophrenia patients (total n = 177) and controls (total n = 249; age = 18-61 years) were ascertained with three 3T Siemens MRI scanners. Whole-brain and regional FA values were extracted using ENIGMA-DTI protocols. Statistics were evaluated using mega- and meta-analyses to detect effects of diagnosis and age-by-diagnosis interactions. In mega-analysis of whole-brain averaged FA, schizophrenia patients had lower FA (P = 10 -11 ) and faster age-related decline in FA (P = 0.02) compared with controls. Tract-specific heterochronicity measures, that is, abnormal rates of adolescent maturation and aging explained approximately 50% of the regional variance effects of diagnosis and age-by-diagnosis interaction in patients. Interactive, three-dimensional visualization of the results is available at www.enigma-viewer.org. WM tracts that mature later in life appeared more sensitive to the pathophysiology of schizophrenia and were more susceptible to faster age-related decline in FA values. Hum Brain Mapp 37:4673-4688, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiu Deqiang; Kwong, Dora; Chan, Godfrey

Purpose: To test the hypothesis that fractional anisotropy (FA) is more severely reduced in white matter of the frontal lobe compared with the parietal lobe after receiving the same whole-brain irradiation dose in a cohort of childhood medulloblastoma survivors. Methods and Materials: Twenty-two medulloblastoma survivors (15 male, mean [{+-} SD] age = 12.1 {+-} 4.6 years) and the same number of control subjects (15 male, aged 12.0 {+-} 4.2 years) were recruited for diffusion tensor magnetic resonance imaging scans. Using an automated tissue classification method and the Talairach Daemon atlas, FA values of frontal and parietal lobes receiving the samemore » radiation dose, and the ratio between them were quantified and denoted as FFA, PFA, and FA{sub f/p}, respectively. The Mann-Whitney U test was used to test for significant differences of FFA, PFA, and FA{sub f/p} between medulloblastoma survivors and control subjects. Results: Frontal lobe and parietal lobe white matter FA were found to be significantly less in medulloblastoma survivors compared with control subjects (frontal p = 0.001, parietal p = 0.026). Moreover, these differences were found to be discrepant, with the frontal lobe having a significantly larger difference in FA compared with the parietal lobe. The FA{sub f/p} of control and medulloblastoma survivors was 1.110 and 1.082, respectively (p = 0.029). Conclusion: Discrepant FA changes after the same irradiation dose suggest radiosensitivity of the frontal lobe white matter compared with the parietal lobe. Special efforts to address the potentially vulnerable frontal lobe after treatment with whole-brain radiation may be needed so as to balance disease control and treatment-related morbidity.« less

Pathology of callosal damage in ALS: An ex-vivo, 7 T diffusion tensor MRI study.

PubMed

Cardenas, Agustin M; Sarlls, Joelle E; Kwan, Justin Y; Bageac, Devin; Gala, Zachary S; Danielian, Laura E; Ray-Chaudhury, Abhik; Wang, Hao-Wei; Miller, Karla L; Foxley, Sean; Jbabdi, Saad; Welsh, Robert C; Floeter, Mary Kay

2017-01-01

The goal of this study was to better understand the changes in tissue microstructure that underlie white matter diffusion changes in ALS patients. Diffusion tensor imaging was carried out in postmortem brains of 4 ALS patients and two subjects without neurological disease on a 7 T MRI scanner using steady-state free precession sequences. Fractional anisotropy (FA) was measured in the genu, body, and splenium of the corpus callosum in formalin-fixed hemispheres. FA of the body and genu was expressed as ratio to FA of the splenium, a region unaffected in ALS. After imaging, tissue sections of the same segments of the callosum were stained for markers of different tissue components. Coded image fields were rated for pathological changes by blinded raters. The FA body/FA splenium ratio was reduced in ALS patients compared to controls. Patchy areas of myelin pallor and cells immunostained for CD68, a microglial-macrophage marker, were only observed in the body of the callosum of ALS patients. Blinded ratings showed increased CD68 + microglial cells in the body of the corpus callosum in ALS patients, especially those with C9orf72 mutations, and increased reactive astrocytes throughout the callosum. Reduced FA of the corpus callosum in ALS results from complex changes in tissue microstructure. Callosal segments with reduced FA had large numbers of microglia-macrophages in addition to loss of myelinated axons and astrogliosis. Microglial inflammation contributed to reduced FA in ALS, and may contribute to a pro-inflammatory state, but further work is needed to determine their role.

Diffuse Interstitial Brain Edema in Patients With End-Stage Renal Disease Undergoing Hemodialysis: A Tract-Based Spatial Statistics Study

PubMed Central

Kong, Xiang; Wen, Ji-qiu; Qi, Rong-feng; Luo, Song; Zhong, Jian-hui; Chen, Hui-juan; Ji, Gong-jun; Lu, Guang Ming; Zhang, Long Jiang

2014-01-01

Abstract To investigate white matter (WM) alterations and their correlation with cognition function in end-stage renal disease (ESRD) patients undergoing hemodialysis (HD) using diffusion tensor imaging (DTI) with tract-based spatial statistics (TBSS) approach. This prospective HIPAA-complaint study was approved by our institutional review board. Eighty HD ESRD patients and 80 sex- and age-matched healthy controls were included. Neuropsychological (NP) tests and laboratory tests, including serum creatinine and urea, were performed. DTI data were processed to obtain fractional anisotropy (FA) and mean diffusivity (MD) maps with TBSS. FA and MD difference between the 2 groups were compared. We also explored the associations of FA values in WM regions of lower FA with ages, NP tests, disease, and dialysis durations, serum creatinine and urea levels of ESRD patients. Compared with controls, HD ESRD patients had lower FA value in the corpus callosum, bilateral corona radiate, posterior thalamic radiation, left superior longitudinal fasciculus, and right cingulum (P < 0.05, FWE corrected). Almost all WM regions had increased MD in HD ESRD patients compared with controls (P < 0.05, FWE corrected). In some regions with lower FA, FA values showed moderate correlations with ages, NP tests, and serum urea levels. There was no correlation between FA values and HD durations, disease durations, and serum creatinine levels of ESRD patients (all P > 0.05). Diffuse interstitial brain edema and moderate WM integrity disruption occurring in HD ESRD patients, which correlated with cognitive dysfunction, and serum urea levels might be a risk factor for these WM changes. PMID:25526483

Fetal diffusion tensor quantification of brainstem pathology in Chiari II malformation.

PubMed

Woitek, Ramona; Prayer, Daniela; Weber, Michael; Amann, Gabriele; Seidl, Rainer; Bettelheim, Dieter; Schöpf, Veronika; Brugger, Peter C; Furtner, Julia; Asenbaum, Ulrika; Kasprian, Gregor

2016-05-01

This prenatal MRI study evaluated the potential of diffusion tensor imaging (DTI) metrics to identify changes in the midbrain of fetuses with Chiari II malformations compared to fetuses with mild ventriculomegaly, hydrocephalus and normal CNS development. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were calculated from a region of interest (ROI) in the midbrain of 46 fetuses with normal CNS, 15 with Chiari II malformations, eight with hydrocephalus and 12 with mild ventriculomegaly. Fetuses with different diagnoses were compared group-wise after age-matching. Axial T2W-FSE sequences and single-shot echo planar DTI sequences (16 non-collinear diffusion gradient-encoding directions, b-values of 0 and 700 s/mm(2), 1.5 Tesla) were evaluated retrospectively. In Chiari II malformations, FA was significantly higher than in age-matched fetuses with a normal CNS (p = .003), while ADC was not significantly different. No differences in DTI metrics between normal controls and fetuses with hydrocephalus or vetriculomegaly were detected. DTI can detect and quantify parenchymal alterations of the fetal midbrain in Chiari II malformations. Therefore, in cases of enlarged fetal ventricles, FA of the fetal midbrain may contribute to the differentiation between Chiari II malformation and other entities. • FA in the fetal midbrain is elevated in Chiari II malformations. • FA is not elevated in hydrocephalus and mild ventriculomegaly without Chiari II. • Measuring FA may help distinguish different causes for enlarged ventricles prenatally. • Elevated FA may aid in the diagnosis of open neural tube defects. • Elevated FA might contribute to stratification for prenatal surgery in Chiari II.

Hydrogenation and hydrodeoxygenation of biomass-derived oxygenates to liquid alkanes for transportation fuels.

PubMed

Sun, Shaohui; Yang, Ruishu; Wang, Xin; Yan, Shaokang

2018-04-01

An attractive approach for the production of transportation fuels from renewable biomass resources is to convert oxygenates into alkanes. In this paper, C 5 -C 20 alkanes formed via the hydrogenation and hydrodeoxygenation of the oligomers of furfuryl alcohol(FA) can be used as gasoline, diesel and jet fuel fraction. The first step of the process is the oligomers of FA convert into hydrogenated products over Raney Ni catalyst in a batch reactor. The second step of the process converts hydrogenated products to alkanes via hydrodeoxygenation over different bi-functional catalysts include hydrogenation and acidic deoxidization active sites. After this process, the oxygen content decreased from 22.1 wt% in the oligomers of FA to 0.58 wt% in the hydrodeoxygenation products.

Folic acid mitigated cardiac dysfunction by normalizing the levels of tissue inhibitor of metalloproteinase and homocysteine-metabolizing enzymes postmyocardial infarction in mice

PubMed Central

Qipshidze, Natia; Tyagi, Neetu; Sen, Utpal; Givvimani, Srikanth; Metreveli, Naira; Lominadze, David

2010-01-01

Myocardial infarction (MI) results in significant metabolic derangement, causing accumulation of metabolic by product, such as homocysteine (Hcy). Hcy is a nonprotein amino acid generated during nucleic acid methylation and demethylation of methionine. Folic acid (FA) decreases Hcy levels by remethylating the Hcy to methionine, by 5-methylene tetrahydrofolate reductase (5-MTHFR). Although clinical trials were inconclusive regarding the role of Hcy in MI, in animal models, the levels of 5-MTHFR were decreased, and FA mitigated the MI injury. We hypothesized that FA mitigated MI-induced injury, in part, by mitigating cardiac remodeling during chronic heart failure. Thus, MI was induced in 12-wk-old male C57BL/J mice by ligating the left anterior descending artery, and FA (0.03 g/l in drinking water) was administered for 4 wk after the surgery. Cardiac function was assessed by echocardiography and by a Millar pressure-volume catheter. The levels of Hcy-metabolizing enzymes, cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE), and 5-MTHFR, were estimated by Western blot analyses. The results suggest that FA administered post-MI significantly improved cardiac ejection fraction and induced tissue inhibitor of metalloproteinase, CBS, CSE, and 5-MTHFR. We showed that FA supplementation resulted in significant improvement of myocardial function after MI. The study eluted the importance of homocysteine (Hcy) metabolism and FA supplementation in cardiovascular disease. PMID:20802128

[Diffusion tensor imaging findings in first-episode and chronic schizophrenics].

PubMed

Wei, Qin-Ling; Kang, Zhuang; Wu, Xiao-Li; Zhang, Jin-Bei; Li, Lei-Jun; Zheng, Liang-Rong; Guo, Xiao-Feng; Zhao, Jing-Ping

2011-08-23

To investigate the integrity of white matters in first-episode and chronic schizophrenics. For this study, 39 first-episode and 38 chronic schizophrenics, 69 healthy controls (age, gender and years of received education no significantly different from those of the patients) underwent diffusion weighted images with a single-shot echo planar imaging (EPI) sequence aligned to the straight axial plane. The fractional anisotropy (FA) images of three groups underwent one-way ANOVA with the methods of voxel-based morphometric (VBM) analysis. (1) There were three brain regions where the FA values of white matter were different among three groups: right caudate nucleus (MNI: 20, 12, 14; cluster = 432 voxels; FA value: 0.36 ± 0.18 vs 0.35 ± 0.24 vs 0.38 ± 0.17), left insula (MNI: -32, 18, 2; cluster = 204 voxels; FA value: 0.35 ± 0.31 vs 0.33 ± 0.24 vs 0.36 ± 0.21) and right anterior cingulate (MNI: 16, 36, 12; cluster = 132 voxels; FA value: 0.35 ± 0.29 vs 0.34 ± 0.31 vs 0.37 ± 0.25). (2) The mean FA values of the three brain regions of two patients groups decreased versus those of healthy controls (P < 0.05). (3) The mean FA values of left insular region in chronic patients decreased versus those of the first-episode patients (P < 0.05). The reduced integrity of white matter may play an etiological role in schizophrenia and the changes are probably progressive.

The effect of sex and handedness on white matter anisotropy: a diffusion tensor magnetic resonance imaging study.

PubMed

Powell, J L; Parkes, L; Kemp, G J; Sluming, V; Barrick, T R; García-Fiñana, M

2012-04-05

Diffusion tensor magnetic resonance imaging provides a way of assessing the asymmetry of white matter (WM) connectivity, the degree of anisotropic diffusion within a given voxel being a marker of coherently bundled myelinated fibers. Voxel-based statistical analysis was performed on fractional anisotropy (FA) images of 42 right- and 40 left-handers, to assess differences in underlying WM anisotropy and FA asymmetry across the whole brain. Right-handers show greater anisotropy than left-handers in the uncinate fasciculus (UF) within the limbic lobe, and WM underlying prefrontal cortex, medial and inferior frontal gyri. Significantly greater leftward FA asymmetry in cerebellum posterior lobe is seen in left- than right-handers, and males show significantly greater rightward (right-greater-than-left) FA asymmetry in regions of middle occipital lobe, medial temporal gyrus, and a region of the superior longitudinal fasciculus underlying the supramarginal gyrus. Leftward (left-greater-than-right) anisotropy is found in regions of the arcuate fasciculus (AF), UF, and WM underlying pars triangularis in both handedness groups, with right-handers alone showing additional leftward FA asymmetry along the length of the superior temporal gyrus. Overall results indicate that although both handedness groups show anisotropy in similar WM regions, greater anisotropy is observed in right-handers compared with left-handers. The largest differences in FA asymmetry are found between males and females, suggesting a greater effect of sex than handedness on FA asymmetry. Copyright © 2012 IBRO. Published by Elsevier Ltd. All rights reserved.

Characterization of DTI Indices in the Cervical, Thoracic, and Lumbar Spinal Cord in Healthy Humans

PubMed Central

Bosma, Rachael L.; Stroman, Patrick W.

2012-01-01

The aim of this study was to characterize in vivo measurements of diffusion along the length of the entire healthy spinal cord and to compare DTI indices, including fractional anisotropy (FA) and mean diffusivity (MD), between cord regions. The objective is to determine whether or not there are significant differences in DTI indices along the cord that must be considered for future applications of characterizing the effects of injury or disease. A cardiac gated, single-shot EPI sequence was used to acquire diffusion-weighted images of the cervical, thoracic, and lumbar regions of the spinal cord in nine neurologically intact subjects (19 to 22 years). For each cord section, FA versus MD values were plotted, and a k-means clustering method was applied to partition the data according to tissue properties. FA and MD values from both white matter (average FA = 0.69, average MD = 0.93 × 10−3 mm2/s) and grey matter (average FA = 0.44, average MD = 1.8 × 10−3 mm2/s) were relatively consistent along the length of the cord. PMID:22295179

Computer aided diagnosis system for Alzheimer disease using brain diffusion tensor imaging features selected by Pearson's correlation.

PubMed

Graña, M; Termenon, M; Savio, A; Gonzalez-Pinto, A; Echeveste, J; Pérez, J M; Besga, A

2011-09-20

The aim of this paper is to obtain discriminant features from two scalar measures of Diffusion Tensor Imaging (DTI) data, Fractional Anisotropy (FA) and Mean Diffusivity (MD), and to train and test classifiers able to discriminate Alzheimer's Disease (AD) patients from controls on the basis of features extracted from the FA or MD volumes. In this study, support vector machine (SVM) classifier was trained and tested on FA and MD data. Feature selection is done computing the Pearson's correlation between FA or MD values at voxel site across subjects and the indicative variable specifying the subject class. Voxel sites with high absolute correlation are selected for feature extraction. Results are obtained over an on-going study in Hospital de Santiago Apostol collecting anatomical T1-weighted MRI volumes and DTI data from healthy control subjects and AD patients. FA features and a linear SVM classifier achieve perfect accuracy, sensitivity and specificity in several cross-validation studies, supporting the usefulness of DTI-derived features as an image-marker for AD and to the feasibility of building Computer Aided Diagnosis systems for AD based on them. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

The impact of humic and fulvic acids on the dynamic properties of liposome membranes: the ESR method.

PubMed

Man, Dariusz; Pisarek, Izabella; Braczkowski, Michał; Pytel, Barbara; Olchawa, Ryszard

2014-06-01

This paper presents the results of research on the influence of two fractions of humic substances (HS): fulvic acids (FA) and humic acids (HA), as a function of concentration, on the liposome membranes formed from egg yolk lecithin (EYL). The concentration of HS in relation to EYL changed from 0% to 10% by weight. The influence of HS on various areas of membranes: interphase water-lipid, in the lipid layer just below the polar part of the membrane and in the middle of the lipid bilayer, was investigated by different spin labels (TEMPO, DOXYL 5, DOXYL 16). The study showed that HA slightly decreased the fluidity of the analyzed membranes on the surface layer, while FA significantly liquidated the center of the lipid bilayer. The strong effect of both fractions of HS on the concentration of free radicals as a function of time was also described.

Effects of partly replacing dietary starch with fiber and fat on milk production and energy partitioning.

PubMed

Boerman, J P; Potts, S B; VandeHaar, M J; Lock, A L

2015-10-01

The effects of partly replacing dietary starch with fiber and fat to provide a diet with similar net energy for lactation (NEL) density on yields of milk and milk components and on energy partitioning were evaluated in a crossover design experiment. Holstein cows (n = 32; 109 ± 22 d in milk, mean ± standard deviation) were randomly assigned to treatment sequence. Treatments were a high-starch diet containing 33% corn grain (mixture of dry ground and high-moisture corn; HS) or a high-fiber, high-fat diet containing 2.5% palmitic acid-enriched fatty acid (FA) supplement (HFF). Diets contained corn silage, alfalfa silage, and wheat straw as forage sources; HS contained 32% starch, 3.2% FA, and 25% neutral detergent fiber, whereas HFF contained 16% starch, 5.4% FA, and 33% neutral detergent fiber. Compared with HS, the HFF treatment reduced milk yield, milk protein concentration, and milk protein yield, but increased milk fat concentration, milk fat yield, milk energy output, and milk to feed ratio (energy-corrected milk/dry matter intake). The HFF treatment reduced the yield of de novo synthesized (< 16-carbon) milk FA and increased the yield of 16-carbon milk FA. Yield of preformed (> 16-carbon) milk FA was not different. The HFF treatment increased plasma concentrations of triglycerides and nonesterified fatty acids, but decreased plasma concentration of insulin. Compared with HS, the HFF treatment reduced body weight gain, change in body condition score, and fat thickness over the rump and rib. Calculated body energy gain, as a fraction of NEL use, was less for HFF than HS, whereas milk energy as a fraction of NEL use was increased for HFF. We concluded that the 2 treatments resulted in similar apparent NEL densities and intakes, but the HS treatment partitioned more energy toward body gain whereas the HFF treatment partitioned more energy toward milk. A high-fiber, high-fat diet might diminish the incidence of over conditioning in mid-lactation cows while maintaining high milk production. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

White Matter Injuries in Mild Traumatic Brain Injury and Posttraumatic Migraines: Diffusion Entropy Analysis.

PubMed

Delic, Joseph; Alhilali, Lea M; Hughes, Marion A; Gumus, Serter; Fakhran, Saeed

2016-06-01

Purpose To determine the performance of Shannon entropy (SE) as a diagnostic tool in patients with mild traumatic brain injury (mTBI) with posttraumatic migraines (PTMs) and those without PTMs on the basis of analysis of fractional anisotropy (FA) maps. Materials and Methods The institutional review board approved this retrospective study, with waiver of informed consent. FA maps were obtained and neurocognitive testing was performed in 74 patients with mTBI (57 with PTM, 17 without PTM). FA maps were obtained in 22 healthy control subjects and in 20 control patients with migraine headaches. Mean FA and SE were extracted from total brain FA histograms and were compared between patients with mTBI and control subjects and between patients with and those without PTM. Mean FA and SE were correlated with clinical variables and were used to determine the areas under the receiver operating characteristic curve (AUCs) and likelihood ratios for mTBI and development of PTM. Results Patients with mTBI had significantly lower SE (P < .001) and trended toward lower mean FA (P = .07) compared with control subjects. SE inversely correlated with time to recovery (TTR) (r = -0.272, P = .02). Patients with mTBI with PTM had significantly lower SE (P < .001) but not mean FA (P = .15) than did other patients with mTBI. SE provided better discrimination between patients with mTBI and control subjects than mean FA (AUC = 0.92; P = .01), as well as better discrimination between patients with mTBI with PTM and those without PTM (AUC = 0.85; P < .001). SE of less than 0.751 resulted in a 16.1 increased likelihood of having experienced mTBI and a 3.2 increased likelihood of developing PTM. Conclusion SE more accurately reveals mTBI than mean FA, more accurately reveals those patients with mTBI who develop PTM, and inversely correlates with TTR. (©) RSNA, 2016.

Effect of lignin linkages with other plant cell wall components on in vitro and in vivo neutral detergent fiber digestibility and rate of digestion of grass forages.

PubMed

Raffrenato, E; Fievisohn, R; Cotanch, K W; Grant, R J; Chase, L E; Van Amburgh, M E

2017-10-01

The objective of this study was to correlate in vitro and in vivo neutral detergent fiber (NDF) digestibility (NDFD) with the chemical composition of forages and specific chemical linkages, primarily ester- and ether-linked para-coumaric (pCA) and ferulic acids (FA) in forages fed to dairy cattle. The content of acid detergent lignin (ADL) and its relationship with NDF does not fully explain the observed variability in NDFD. The ferulic and p-coumaric acid linkages between ADL and cell wall polysaccharides, rather than the amount of ADL, might be a better predictor of NDFD. Twenty-three forages, including conventional and brown midrib corn silages and grasses at various stages of maturity were incubated in vitro for measurement of 24-h and 96-h NDFD. Undigested and digested residues were analyzed for NDF, acid detergent fiber (ADF), ADL, and Klason lignin (KL); ester- and ether-linked pCA and FA were determined in these fractions. To determine whether in vitro observations of ester- and ether-linked pCA and FA and digestibility were similar to in vivo observations, 3 corn silages selected for digestibility were fed to 6 ruminally fistulated cows for 3 wk in 3 iso-NDF diets. Intact samples and NDF and ADF residues of diet, rumen, and feces were analyzed for ester- and ether-linked pCA and FA. From the in vitro study, the phenolic acid content (total pCA and FA) was highest for corn silages, and overall the content of ester- and ether-linked pCA and FA in both NDF and ADF residues were correlated with NDF digestibility parameters, reflecting the competitive effect of these linkages on digestibility. Also, Klason lignin and ADL were negatively correlated with ether-linked ferulic acid on an NDF basis. Overall, esterified FA and esterified pCA were negatively correlated with all of the measured fiber fractions on both a dry matter and an NDF basis. The lignin content of the plant residues and chemical linkages explained most of the variation in both rate and extent of NDF digestion but not uniformly among forages, ranging from 56 to 99%. The results from the in vivo study were similar to the in vitro data, demonstrating the highest total-tract aNDF digestibility (70%; NDF analysis conducted with α-amylase and sodium sulfite) for cows fed the corn silage with the lowest ester- and ether-linked pCA content in the NDF fraction. In this study, digestibility of forage fiber was influenced by the linkages among lignin and the carbohydrate moieties, which vary by hybrid and species and most likely vary by the agronomic conditions under which the plant was grown. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Concomitant Fractional Anisotropy and Volumetric Abnormalities in Temporal Lobe Epilepsy: Cross-Sectional Evidence for Progressive Neurologic Injury

PubMed Central

Gerdes, Jan S.; Weber, Bernd; Deppe, Michael

2012-01-01

Background In patients with temporal lobe epilepsy and associated hippocampal sclerosis (TLEhs) there are brain abnormalities extending beyond the presumed epileptogenic zone as revealed separately in conventional magnetic resonance imaging (MRI) and MR diffusion tensor imaging (DTI) studies. However, little is known about the relation between macroscopic atrophy (revealed by volumetric MRI) and microstructural degeneration (inferred by DTI). Methodology/Principal Findings For 62 patients with unilateral TLEhs and 68 healthy controls, we determined volumes and mean fractional anisotropy (FA) of ipsilateral and contralateral brain structures from T1-weighted and DTI data, respectively. We report significant volume atrophy and FA alterations of temporal lobe, subcortical and callosal regions, which were more diffuse and bilateral in patients with left TLEhs relative to right TLEhs. We observed significant relationships between volume loss and mean FA, particularly of the thalamus and putamen bilaterally. When corrected for age, duration of epilepsy was significantly correlated with FA loss of an anatomically plausible route - including ipsilateral parahippocampal gyrus and temporal lobe white matter, the thalamus bilaterally, and posterior regions of the corpus callosum that contain temporal lobe fibres - that may be suggestive of progressive brain degeneration in response to recurrent seizures. Conclusions/Significance Chronic TLEhs is associated with interrelated DTI-derived and volume-derived brain degenerative abnormalities that are influenced by the duration of the disorder and the side of seizure onset. This work confirms previously contradictory findings by employing multi-modal imaging techniques in parallel in a large sample of patients. PMID:23071638

Delayed injection of polypyrrole doped with iodine particle suspension after spinal cord injury in rats improves functional recovery and decreased tissue damage evaluated by 3.0 Tesla in vivo magnetic resonance imaging.

PubMed

Mondragon-Lozano, Rodrigo; Ríos, Camilo; Roldan-Valadez, Ernesto; Cruz, Guillermo J; Olayo, Maria G; Olayo, Roberto; Salgado-Ceballos, Hermelinda; Morales, Juan; Mendez-Armenta, Marisela; Alvarez-Mejia, Laura; Fabela, Omar; Morales-Guadarrama, Axayacatl; Sánchez-Torres, Stephanie; Diaz-Ruiz, Araceli

2017-04-01

Traumatic spinal cord injury (SCI) causes irreversible damage with loss of motor, sensory, and autonomic functions. Currently, there is not an effective treatment to restore the lost neurologic functions. Injection of polypyrrole-iodine(PPy-I) particle suspension is proposed as a therapeutic strategy. This is an in vivo animal study. This study evaluates the use of such particles in rats after SCI by examining spared nervous tissue and the Basso, Beattie, and Bresnahan (BBB) scale to evaluate the functional outcome. Diffusive magnetic resonance imaging (MRI) was employed to measure the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) as non-invasive biomarkers of damage after SCI. Fractional anisotropy decreased, whereas ADC increased in all groups after the lesion. There were significant differences in FA when compared with the SCI-PPy-I group versus the SCI group (p<.05). Significant positive correlations between BBB and FA (r 2 =0.449, p<.05) and between FA and preserved tissue (r 2 =0.395, p<.05) were observed, whereas significant negative associations between BBB and ADC (r 2 =0.367, p<.05) and between ADC and preserved tissue (r 2 =0.421, p<.05) were observed. The results suggested that PPy-I is neuroprotective as it decreased the amount of damaged tissue while improving the motor function. Non-invasive MRI proved to be useful in the characterization of SCI and recovery. Copyright © 2016 Elsevier Inc. All rights reserved.

Enantioselective Pharmacokinetics of α-Lipoic Acid in Rats

PubMed Central

Uchida, Ryota; Okamoto, Hinako; Ikuta, Naoko; Terao, Keiji; Hirota, Takashi

2015-01-01

α-Lipoic acid (LA) is widely used for nutritional supplements as a racemic mixture, even though the R enantiomer is biologically active. After oral administration of the racemic mixture (R-α-lipoic acid (RLA) and S-α-lipoic acid (SLA) mixed at the ratio of 50:50) to rats, RLA showed higher plasma concentration than SLA, and its area under the plasma concentration-time curve from time zero to the last (AUC) was significantly about 1.26 times higher than that of SLA. However, after intravenous administration of the racemic mixture, the pharmacokinetic profiles, initial concentration (C0), AUC, and half-life (T1/2) of the enantiomers were not significantly different. After oral and intraduodenal administration of the racemic mixture to pyrolus-ligated rats, the AUCs of RLA were significantly about 1.24 and 1.32 times higher than that of SLA, respectively. In addition, after intraportal administration the AUC of RLA was significantly 1.16 times higher than that of SLA. In conclusion, the enantioselective pharmacokinetics of LA in rats arose from the fraction absorbed multiplied by gastrointestinal availability (FaFg) and hepatic availability (Fh), and not from the total clearance. PMID:26402669

Enantioselective Pharmacokinetics of α-Lipoic Acid in Rats.

PubMed

Uchida, Ryota; Okamoto, Hinako; Ikuta, Naoko; Terao, Keiji; Hirota, Takashi

2015-09-21

α-Lipoic acid (LA) is widely used for nutritional supplements as a racemic mixture, even though the R enantiomer is biologically active. After oral administration of the racemic mixture (R-α-lipoic acid (RLA) and S-α-lipoic acid (SLA) mixed at the ratio of 50:50) to rats, RLA showed higher plasma concentration than SLA, and its area under the plasma concentration-time curve from time zero to the last (AUC) was significantly about 1.26 times higher than that of SLA. However, after intravenous administration of the racemic mixture, the pharmacokinetic profiles, initial concentration (C₀), AUC, and half-life (T1/2) of the enantiomers were not significantly different. After oral and intraduodenal administration of the racemic mixture to pyrolus-ligated rats, the AUCs of RLA were significantly about 1.24 and 1.32 times higher than that of SLA, respectively. In addition, after intraportal administration the AUC of RLA was significantly 1.16 times higher than that of SLA. In conclusion, the enantioselective pharmacokinetics of LA in rats arose from the fraction absorbed multiplied by gastrointestinal availability (FaFg) and hepatic availability (Fh), and not from the total clearance.

Repeatability of chemical-shift-encoded water-fat MRI and diffusion-tensor imaging in lower extremity muscles in children.

PubMed

Ponrartana, Skorn; Andrade, Kristine E; Wren, Tishya A L; Ramos-Platt, Leigh; Hu, Houchun H; Bluml, Stefan; Gilsanz, Vicente

2014-06-01

The purpose of this study was to assess the repeatability of water-fat MRI and diffusion-tensor imaging (DTI) as quantitative biomarkers of pediatric lower extremity skeletal muscle. MRI at 3 T of a randomly selected thigh and lower leg of seven healthy children was studied using water-fat separation and DTI techniques. Muscle-fat fraction, apparent diffusion coefficient (ADC), and fractional anisotropy (FA) values were calculated. Test-retest and interrater repeatability were assessed by calculating the Pearson correlation coefficient, intraclass correlation coefficient, and Bland-Altman analysis. Bland-Altman plots show that the mean difference between test-retest and interrater measurements of muscle-fat fraction, ADC, and FA was near 0. The correlation coefficients and intraclass correlation coefficients were all between 0.88 and 0.99 (p < 0.05), suggesting excellent reliability of the measurements. Muscle-fat fraction measurements from water-fat MRI exhibited the highest intraclass correlation coefficient. Interrater agreement was consistently better than test-retest comparisons. Water-fat MRI and DTI measurements in lower extremity skeletal muscles are objective repeatable biomarkers in children. This knowledge should aid in the understanding of the number of participants needed in clinical trials when using these determinations as an outcome measure to noninvasively monitor neuromuscular disease.

Associations between autistic traits and fractional anisotropy values in white matter tracts in a nonclinical sample of young adults.

PubMed

Bradstreet, Lauren E; Hecht, Erin E; King, Tricia Z; Turner, Jessica L; Robins, Diana L

2017-01-01

Whereas a number of studies have examined relationships among brain activity, social cognitive skills, and autistic traits, fewer studies have evaluated whether structural connections among brain regions relate to these traits and skills. Uncinate fasciculus (UF) and inferior longitudinal fasciculus (ILF) are white matter tracts that may underpin the behavioral expression of these skills because they connect regions within or provide sensory information to brain areas implicated in social cognition, and structural differences in these tracts have been associated with autistic traits. We examined relationships among self-reported autistic traits, mentalizing, and water diffusivity in UF and ILF in a nonclinical sample of 24 young adults (mean age = 21.92 years, SD = 4.72 years; 15 women). We measured autistic traits using the Autism-Spectrum Quotient, and we measured mentalizing using the Dynamic Interactive Shapes Clips task. We used Tract-Based Spatial Statistics and randomize to examine relationships among fractional anisotropy (FA) values in bilateral ILF and UF, age, cognitive abilities, autistic traits, and mentalizing. Autistic traits were positively related to FA values in left ILF. No other relationships between FA values and other variables were significant. Results suggest that left ILF may be involved in the expression of autistic traits in individuals without clinical diagnoses.

Fornix Under Water? Ventricular Enlargement Biases Forniceal Diffusion Magnetic Resonance Imaging Indices in Anorexia Nervosa.

PubMed

Kaufmann, Lisa-Katrin; Baur, Volker; Hänggi, Jürgen; Jäncke, Lutz; Piccirelli, Marco; Kollias, Spyros; Schnyder, Ulrich; Pasternak, Ofer; Martin-Soelch, Chantal; Milos, Gabriella

2017-07-01

Acute anorexia nervosa (AN) is characterized by reduced brain mass and corresponding increased sulcal and ventricular cerebrospinal fluid. Recent studies of white matter using diffusion tensor imaging consistently identified alterations in the fornix, such as reduced fractional anisotropy (FA). However, because the fornix penetrates the ventricles, it is prone to cerebrospinal fluid-induced partial volume effects that interfere with a valid assessment of FA. We investigated the hypothesis that in the acute stage of AN, FA of the fornix is markedly affected by ventricular volumes. First, using diffusion tensor imaging data we established the inverse associations between forniceal FA and volumes of the third and lateral ventricles in a prestudy with 32 healthy subjects to demonstrate the strength of ventricular influence on forniceal FA independent of AN. Second, we investigated a sample of 25 acute AN patients and 25 healthy control subjects. Using ventricular volumes as covariates markedly reduced the group effect of forniceal FA, even with tract-based spatial statistics focusing only on the center of the fornix. In addition, after correcting for free water on voxel level, the group differences in forniceal FA between AN patients and controls disappeared completely. It is unlikely that microstructural changes affecting FA occurred in the fornix of AN patients. Previously identified alterations in acute AN may have been biased by partial volume effects and the proposed central role of this structure in the pathophysiology may need to be reconsidered. Future studies on white matter alterations in AN should carefully deal with partial volume effects. Copyright © 2017 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Diffusion tensor imaging of white matter after cranial radiation in children for medulloblastoma: correlation with IQ.

PubMed

Mabbott, Donald J; Noseworthy, Michael D; Bouffet, Eric; Rockel, Conrad; Laughlin, Suzanne

2006-07-01

Treatment of children with cranial-spinal radiation (CSR) for brain tumors is associated with adverse intellectual outcome and white matter damage. However, the correlation between IQ and measures of white matter integrity has received little attention. We examined apparent diffusion coefficient (ADC), fractional anisotropy (FA), and intelligence in pediatric patients treated with CSR for medulloblastoma relative to control subjects. ADC and FA measures were obtained for eight patients and eight control children and evaluated in multiple regions of interest in the cerebral hemispheres. Mean ADC and mean FA for each region were calculated, group differences were evaluated, and the relationship between these measures and intelligence were examined. In our study group, decreased IQ was associated with increased ADC and decreased FA (P < 0.01). Mean IQ for the CSR group was lower than that for the control group, but the difference was not significant when controlling for overall mean FA or ADC (P > 0.10). Overall mean FA was lower and ADC was higher in the CSR group relative to controls (P < 0.01). Specifically, FA was lower in the genu of the corpus callosum, the anterior and posterior limbs of the internal capsule, inferior frontal white matter, and high frontal white matter, and ADC was higher in all regions in patients relative to controls (P < 0.01). Compromised white matter integrity was observed for multiple regions within the cerebral hemispheres following CSR. A novel finding was that microscopic damage in normal-appearing white matter, as indexed by higher ADC and lower FA, was related to poor intellectual outcome relative to age-matched controls.

Editor's Highlight: Lower Fractional Anisotropy in the Globus Pallidus of Asymptomatic Welders, a Marker for Long-Term Welding Exposure.

PubMed

Lee, Eun-Young; Flynn, Michael R; Du, Guangwei; Lewis, Mechelle M; Herring, Amy H; Van Buren, Eric; Van Buren, Scott; Kong, Lan; Mailman, Richard B; Huang, Xuemei

2016-09-01

Welding fumes contain several metals including manganese (Mn), iron (Fe), and copper (Cu) that at high exposure may co-influence welding-related neurotoxicity. The relationship between brain accumulation of these metals and neuropathology, especially in welders with subclinical exposure levels, is unclear. This study examined the microstructural integrity of basal ganglia (BG) regions in asymptomatic welders using diffusion tensor imaging (DTI). Subjects with (n = 43) and without (age- and gender-matched controls; n = 31) history of welding were studied. Occupational questionnaires estimated short-term (HrsW; welding hours and E90; cumulative exposure, past 90 days) and long-term (YrsW; total years welding and ELT; cumulative exposure, lifetime) exposure. Whole blood metal levels (Mn, Fe, and Cu) were obtained. Brain MRI pallidal index (PI), R1 (1/T1), and R2* (1/T2*) were measured to estimate Mn and Fe accumulation in BG [caudate, putamen, and globus pallidus (GP)]. DTI was used to assess BG microstructural differences, and related with exposure measurements. When compared with controls, welders had significantly lower fractional anisotropy (FA) in the GP. In welders, GP FA values showed non-linear relationships to YrsW, blood Mn, and PI. GP FA decreased after a critical level of YrsW or Mn was reached, whereas it decreased with increasing PI values until plateauing at the highest PI values. GP FA, however, did not show any relationship with short-term exposure measurements (HrsW, E90), blood Cu and Fe, or R(2)* values. GP FA captured microstructural changes associated with chronic low-level Mn exposure, and may serve as a biomarker for neurotoxicity in asymptomatic welders. © The Author 2016. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Diffusion tensor imaging of the sural nerve in normal controls☆

PubMed Central

Kim, Boklye; Srinivasan, Ashok; Sabb, Brian; Feldman, Eva L; Pop-Busui, Rodica

2016-01-01

Objective To develop a diffusion tensor imaging (DTI) protocol for assessing the sural nerve in healthy subjects. Methods Sural nerves in 25 controls were imaged using DTI at 3 T with 6, 15, and 32 gradient directions. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were computed from nerve regions of interest co-registered with T2-weighted images. Results Coronal images with 0.5(RL)×2.0(FH)×0.5(AP) mm3 resolution successfully localized the sural nerve. FA maps showed less variability with 32 directions (0.559±0.071) compared to 15(0.590±0.080) and 6(0.659±0.109). Conclusions Our DTI protocol was effective in imaging sural nerves in controls to establish normative FA/ADC, with potential to be used non-invasively in diseased nerves of patients. PMID:24908367

Fluorophore Absorption Size Exclusion Chromatography (FA-SEC): An Alternative Method for High-Throughput Detergent Screening of Membrane Proteins.

PubMed

Lin, Sung-Yao; Sun, Xing-Han; Hsiao, Yu-Hsuan; Chang, Shao-En; Li, Guan-Syun; Hu, Nien-Jen

2016-01-01

Membrane proteins play key roles in many fundamental functions in cells including ATP synthesis, ion and molecule transporter, cell signalling and enzymatic reactions, accounting for ~30% genes of whole genomes. However, the hydrophobic nature of membrane proteins frequently hampers the progress of structure determination. Detergent screening is the critical step in obtaining stable detergent-solubilized membrane proteins and well-diffracting protein crystals. Fluorescence Detection Size Exclusion Chromatography (FSEC) has been developed to monitor the extraction efficiency and monodispersity of membrane proteins in detergent micelles. By tracing the FSEC profiles of GFP-fused membrane proteins, this method significantly enhances the throughput of detergent screening. However, current methods to acquire FSEC profiles require either an in-line fluorescence detector with the SEC equipment or an off-line spectrofluorometer microplate reader. Here, we introduce an alternative method detecting the absorption of GFP (FA-SEC) at 485 nm, thus making this methodology possible on conventional SEC equipment through the in-line absorbance spectrometer. The results demonstrate that absorption is in great correlation with fluorescence of GFP. The comparably weaker absorption signal can be improved by using a longer path-length flow cell. The FA-SEC profiles were congruent with the ones plotted by FSEC, suggesting FA-SEC could be a comparable and economical setup for detergent screening of membrane proteins.

Removal of humic acid using TiO2 photocatalytic process--fractionation and molecular weight characterisation studies.

PubMed

Liu, Sanly; Lim, May; Fabris, Rolando; Chow, Christopher; Chiang, Ken; Drikas, Mary; Amal, Rose

2008-05-01

The photocatalytic removal of humic acid (HA) using TiO2 under UVA irradiation was examined by monitoring changes in the UV(254) absorbance, dissolved organic carbon (DOC) concentration, apparent molecular weight distribution, and trihalomethane formation potentials (THMFPs) over treatment time. A resin fractionation technique in which the samples were fractionated into four components: very hydrophobic acids (VHA), slightly hydrophobic acids, hydrophilic charged (CHA) and hydrophilic neutral (NEU) was also employed to elucidate the changes in the chemical nature of the HA components during treatment. The UVA/TiO2 process was found to be effective in removing more than 80% DOC and 90% UV(254) absorbance. The THMFPs of samples were decreased to below 20 microg l(-1) after treatments, which demonstrate the potential to meet increasingly stringent regulatory level of trihalomethanes in water. Resin fractionation analysis showed that the VHA fraction was decreased considerably as a result of photocatalytic treatments, forming CHA intermediates which were further degraded with increased irradiation time. The NEU fraction, which comprised of non-UV-absorbing low molecular weight compounds, was found to be the most persistent component.

A COMPREHENSIVE EXAMINATION OF WHITE MATTER TRACTS AND CONNECTOMETRY IN MAJOR DEPRESSIVE DISORDER

PubMed Central

Delaparte, Lauren; Yeh, Fang‐Cheng; DeLorenzo, Christine; McGrath, Patrick J.; Weissman, Myrna M.; Adams, Phillip; Fava, Maurizio; Deckersbach, Thilo; McInnis, Melvin G.; Carmody, Thomas J.; Cooper, Crystal M.; Kurian, Benji T.; Lu, Hanzhang; Toups, Marisa S.; Trivedi, Madhukar H.; Parsey, Ramin V.

2015-01-01

Background Major depressive disorder (MDD) is a debilitating disorder characterized by widespread brain abnormalities. The literature is mixed as to whether or not white matter abnormalities are associated with MDD. This study sought to examine fractional anisotropy (FA) in white matter tracts in individuals with MDD using diffusion tensor imaging (DTI). Methods 139 participants with MDD and 39 healthy controls (HC) in a multisite study were included. DTI scans were acquired in 64 directions and FA was determined in the brain using four methods: region of interest (ROI), tract‐based spatial statistics (TBSS), and diffusion tractography. Diffusion connectometry was used to identify white matter pathways associated with MDD. Results There were no significant differences when comparing FA in MDD and HC groups using any method. In the MDD group, there was a significant relationship between depression severity and FA in the right medial orbitofrontal cortex, and between age of onset of MDD and FA in the right caudal anterior cingulate cortex using the ROI method. There was a significant relationship between age of onset and connectivity in the thalamocortical radiation, inferior longitudinal fasciculus, and cerebellar tracts using diffusion connectometry. Conclusions The lack of group differences in FA and connectometry analysis may result from the clinically heterogenous nature of MDD. However, the relationship between FA and depression severity may suggest a state biomarker of depression that should be investigated as a potential indicator of response. Age of onset may also be a significant clinical feature to pursue when studying white matter tracts. PMID:26477532

Diffusion tensor eigenvector directional color imaging patterns in the evaluation of cerebral white matter tracts altered by tumor.

PubMed

Field, Aaron S; Alexander, Andrew L; Wu, Yu-Chien; Hasan, Khader M; Witwer, Brian; Badie, Behnam

2004-10-01

To categorize the varied appearances of tumor-altered white matter (WM) tracts on diffusion tensor eigenvector directional color maps. Diffusion tensor imaging (DTI) was obtained preoperatively in 13 patients with brain tumors ranging from benign to high-grade malignant, including primary and metastatic lesions, and maps of apparent diffusion coefficient (ADC), fractional anisotropy (FA), and major eigenvector direction were generated. Regions of interest (ROIs) were drawn within identifiable WM tracts affected by tumor, avoiding grossly cystic and necrotic regions, known fiber crossings, and gray matter. Patterns of WM tract alteration were categorized on the basis of qualitative analysis of directional color maps and correlation analysis of ADC and FA. Four basic patterns of WM alteration were identified: 1) normal or nearly normal FA and ADC, with abnormal tract location or tensor directions attributable to bulk mass displacement, 2) moderately decreased FA and increased ADC with normal tract locations and tensor directions, 3) moderately decreased FA and increased ADC with abnormal tensor directions, and 4) near isotropy. FA and ADC were inversely correlated for Patterns 1-3 but did not discriminate edema from infiltrating tumor. However, in the absence of mass displacement, infiltrating tumor was found to produce tensor directional changes that were not observed with vasogenic edema, suggesting the possibility of discrimination on the basis of directional statistics. Tumor alteration of WM tracts tends to produce one of four patterns on FA and directional color maps. Clinical application of these patterns must await further study. Copyright 2004 Wiley-Liss, Inc.

Chronic cigarette smoking and the microstructural integrity of white matter in healthy adults

PubMed Central

Paul, Robert H.; Grieve, Stuart M.; Niaura, Raymond; David, Sean P.; Laidlaw, David H.; Cohen, Ronald; Sweet, Lawrence; Taylor, George; Clark, C. Richard; Pogun, Sakire; Gordon, Evian

2008-01-01

Results from recent studies suggest that chronic cigarette smoking is associated with increased white matter volume in the brain as determined by in vivo neuroimaging. We used diffusion tensor imaging to examine the microstructural integrity of the white matter in 10 chronic smokers and 10 nonsmokers. All individuals were healthy, without histories of medical or psychiatric illness. Fractional anisotropy (FA) and trace were measured in the genu, body, and splenium of the corpus callosum. FA provides a measure of directional versus nondirectional water diffusion, whereas trace provides a measure of nondirectional water diffusion. Lower FA and higher trace values are considered to reflect less brain integrity. Voxel-based morphometry was used to define volumes in each of these regions of the corpus callosum. Chronic smokers exhibited significantly higher FA in the body and whole corpus callosum and a strong trend for higher FA in the splenium compared with nonsmokers. FA did not differ between groups in the genu, and neither trace nor white matter volumes differed between groups in any of the regions of interest. When subdivided by Fagerström score (low vs. high), the low Fagerström group exhibited significantly higher FA in the body of the corpus callosum compared with the high Fagerström group and the nonsmokers. These results suggest that, among healthy adults, lower exposure to cigarette smoking is associated with increased microstructural integrity of the white matter compared with either no exposure or higher exposure. Additional studies are needed to further explore differences in white matter integrity between smokers and nonsmokers. PMID:18188754

Childhood trauma- and cannabis-associated microstructural white matter changes in patients with psychotic disorder: a longitudinal family-based diffusion imaging study.

PubMed

Domen, Patrick; Michielse, Stijn; Peeters, Sanne; Viechtbauer, Wolfgang; van Os, Jim; Marcelis, Machteld

2018-05-29

Decreased white matter (WM) integrity in patients with psychotic disorder has been a consistent finding in diffusion tensor imaging (DTI) studies. However, the contribution of environmental risk factors to these WM alterations is rarely investigated. The current study examines whether individuals with (increased risk for) psychotic disorder will show increased WM integrity change over time with increasing levels of childhood trauma and cannabis exposure. DTI scans were obtained from 85 patients with a psychotic disorder, 93 non-psychotic siblings and 80 healthy controls, of which 60% were rescanned 3 years later. In a whole-brain voxel-based analysis, associations between change in fractional anisotropy (ΔFA) and environmental exposures as well as interactions between group and environmental exposure in the model of FA and ΔFA were investigated. Analyses were adjusted for a priori hypothesized confounding variables: age, sex, and level of education. At baseline, no significant associations were found between FA and both environmental risk factors. At follow-up as well as over a 3-year interval, significant interactions between group and, respectively, cannabis exposure and childhood trauma exposure in the model of FA and ΔFA were found. Patients showed more FA decrease over time compared with both controls and siblings when exposed to higher levels of cannabis or childhood trauma. Higher levels of cannabis or childhood trauma may compromise connectivity over the course of the illness in patients, but not in individuals at low or higher than average genetic risk for psychotic disorder, suggesting interactions between the environment and illness-related factors.

Bile Salt Micelles and Phospholipid Vesicles Present in Simulated and Human Intestinal Fluids: Structural Analysis by Flow Field-Flow Fractionation/Multiangle Laser Light Scattering.

PubMed

Elvang, Philipp A; Hinna, Askell H; Brouwers, Joachim; Hens, Bart; Augustijns, Patrick; Brandl, Martin

2016-09-01

Knowledge about colloidal assemblies present in human intestinal fluids (HIFs), such as bile salt micelles and phospholipid vesicles, is regarded of importance for a better understanding of the in vivo dissolution and absorption behavior of poorly soluble drugs (Biopharmaceutics Classification System class II/IV drugs) because of their drug-solubilizing ability. The characterization of these potential drug-solubilizing compartments is a prerequisite for further studies of the mechanistic interplays between drug molecules and colloidal structures within HIFs. The aim of the present study was to apply asymmetrical flow field-flow fractionation (AF4) in combination with multiangle laser light scattering in an attempt to reveal coexistence of colloidal particles in both artificial and aspirated HIFs and to determine their sizes. Asymmetrical flow field-flow fractionation/multiangle laser light scattering analysis of the colloidal phase of intestinal fluids allowed for a detailed insight into the whole spectrum of submicron- to micrometer-sized particles. With respect to the simulated intestinal fluids mimicking fasted and fed state (FaSSIF-V1 and FeSSIF-V1, respectively), FaSSIF contained one distinct size fraction of colloidal assemblies, whereas FeSSIF contained 2 fractions of colloidal species with significantly different sizes. These size fractions likely represent (1) mixed taurocholate-phospholipid-micelles, as indicated by a size range up to 70 nm (in diameter) and a strong UV absorption and (2) small phospholipid vesicles of 90-210 nm diameter. In contrast, within the colloidal phase of the fasted state aspirate of a human volunteer, 4 different size fractions were separated from each other in a consistent and reproducible manner. The 2 fractions containing large particles showed mean sizes of approximately 50 and 200 nm, respectively (intensity-weighted mean diameter, Dz), likely representing mixed cholate/phospholipid micelles and phospholipid vesicles, respectively. The sizes of the smaller 2 fractions being below the size range of multiangle laser light scattering analysis (<20 nm) and their strong UV absorption indicates that they represent either pure cholate micelles or small mixed micelles. Within the colloidal fraction of the fed-state human aspirate, similar colloidal assemblies were detected as in the fasted state human aspirates. The observed differences between SIF and HIF indicate that the simulated intestinal fluids (FaSSIF-V1 and FeSSIF-V1) represent rather simplified models of the real human intestinal environment in terms of coexisting colloidal particles. It is hypothesized that the different supramolecular assemblies detected differ in their lipid composition, which may affect their affinity toward drug compounds and thus the drug-solubilizing capabilities. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Diffusion tensor imaging in preterm infants with punctate white matter lesions.

PubMed

Bassi, Laura; Chew, Andrew; Merchant, Nazakat; Ball, Gareth; Ramenghi, Luca; Boardman, James; Allsop, Joanna M; Doria, Valentina; Arichi, Tomoki; Mosca, Fabio; Edwards, A David; Cowan, Frances M; Rutherford, Mary A; Counsell, Serena J

2011-06-01

Our aim was to compare white matter (WM) microstructure in preterm infants with and without punctate WM lesions on MRI using tract-based spatial statistics (TBSS) and probabilistic tractography. We studied 23 preterm infants with punctate lesions, median GA at birth 30 (25-35) wk, and 23 GA- and sex-matched preterm controls. TBSS and tractography were performed to assess differences in fractional anisotropy (FA) between the two groups at term equivalent age. The impact of lesion load was assessed by performing linear regression analysis of the number of lesions on term MRI versus FA in the corticospinal tracts in the punctate lesions group. FA values were significantly lower in the posterior limb of the internal capsule, cerebral peduncles, decussation of the superior cerebellar peduncles, superior cerebellar peduncles, and pontine crossing tract in the punctate lesions group. There was a significant negative correlation between lesion load at term and FA in the corticospinal tracts (p = 0.03, adjusted r² = 0.467). In conclusion, punctate lesions are associated with altered microstructure in the WM fibers of the corticospinal tract at term equivalent age.

White matter integrity in dementia with Lewy bodies: A Voxel-Based Analysis of Diffusion Tensor Imaging

PubMed Central

Nedelska, Zuzana; Schwarz, Christopher G.; Boeve, Bradley F.; Lowe, Val; Reid, Robert I.; Przybelski, Scott A.; Lesnick, Timothy G.; Gunter, Jeffrey L.; Senjem, Matthew L.; Ferman, Tanis J.; Smith, Glenn E.; Geda, Yonas E.; Knopman, David S.; Petersen, Ronald C.; Jack, Clifford R.; Kantarci, Kejal

2015-01-01

Many patients with dementia with Lewy bodies have overlapping Alzheimer's disease (AD)–related pathology, which may contribute to white matter (WM) diffusivity alterations on diffusion tensor imaging (DTI). Consecutive patients with DLB (n=30), age and sex matched AD patients (n=30), and cognitively normal controls (CN; n=60) were recruited. All subjects underwent DTI, 18F 2-fluoro-deoxy-d-glucose (FDG) and 11C Pittsburgh compound B (PiB) PET scans. DLB patients had reduced fractional anisotropy (FA) in the parieto-occipital WM but not elsewhere compared to CN, and elevated FA in parahippocampal WM compared to AD patients, which persisted after controlling for Aβ load in DLB. The pattern of WM FA alterations on DTI was consistent with the more diffuse posterior parietal and occipital glucose hypometabolism of FDG PET in the cortex. DLB is characterized by a loss of parieto-occipital WM integrity, independent of concomitant AD-related Aβ load. Cortical glucose hypometabolism accompanies WM FA alterations with a concordant pattern of gray and white matter involvement in the parieto-occipital lobes in DLB. PMID:25863527

Diffusion tensor imaging reveals changes in the adult rat brain following long-term and passive moderate acoustic exposure.

PubMed

Abdoli, Sherwin; Ho, Leon C; Zhang, Jevin W; Dong, Celia M; Lau, Condon; Wu, Ed X

2016-12-01

This study investigated neuroanatomical changes following long-term acoustic exposure at moderate sound pressure level (SPL) under passive conditions, without coupled behavioral training. The authors utilized diffusion tensor imaging (DTI) to detect morphological changes in white matter. DTIs from adult rats (n = 8) exposed to continuous acoustic exposure at moderate SPL for 2 months were compared with DTIs from rats (n = 8) reared under standard acoustic conditions. Two distinct forms of DTI analysis were applied in a sequential manner. First, DTI images were analyzed using voxel-based statistics which revealed greater fractional anisotropy (FA) of the pyramidal tract and decreased FA of the tectospinal tract and trigeminothalamic tract of the exposed rats. Region of interest analysis confirmed (p < 0.05) that FA had increased in the pyramidal tract but did not show a statistically significant difference in the FA of the tectospinal or trigeminothalamic tract. The results of the authors show that long-term and passive acoustic exposure at moderate SPL increases the organization of white matter in the pyramidal tract.

Global emissions of the hydrofluorocarbons (HFCs) HFC-365mfc, HFC-245fa, HFC-227ea, and HFC-236fa based on atmospheric observations

NASA Astrophysics Data System (ADS)

Vollmer, M. K.; Miller, B. R.; Rigby, M. L.; Reimann, S.; Muhle, J.; Agage, Soge, Snu Members, Kopri Members

2010-12-01

We report on the atmospheric measurements and global emissions of the hydrofluorocarbons (HFCs) HFC-365mfc (CH3CH2CF2CF3, 1,1,1,3,3-pentafluorobutane), HFC-245fa (CHF2CH2CF3, 1,1,1,3,3-pentafluoropropane), HFC-227ea (CF3CHFCF3, 1,1,1,2,3,3,3-heptafluoropropane), and HFC-236fa (CF3CH2CF3, 1,1,1,3,3,3-hexafluoropropane). These measurements are from in-situ observations at stations of AGAGE (Advanced Global Atmospheric Gases Experiment) and SOGE (System for Observations of Halogenated Greenhouse Gases in Europe), and from the Korean station Gosan. We also report on flask sample measurements from the Antarctic stations King Sejong and Troll, and extend our records back to the 1970s using archived air samples of both hemispheres. All data are used in a global 12-box 2-dimensional atmospheric transport model to derive global abundances and emission estimates. All four HFCs have strongly increased in the atmosphere in recent years with growth rates at nearly 10 %, resulting in dry air mole fractions at the end of 2009 of 0.49 ppt for HFC-365mfc, 1.00 ppt for HFC-245fa, and 0.51 ppt for HFC-227ea. HFC-236fa, for which we report the first atmospheric measurements, is less abundant and has grown to 0.069 ppt at the end of 2009. Our model results show rapidly growing emissions of HFC-365mfc and HFC-245fa after 2002 but surprisingly these have now started to decline to globally 2.7 kt/yr (HFC-365mfc) and 6.1 kt/yr (HFC-245fa). On the other hand HFC-227ea and HFC-236fa show uninterrupted growth in their emissions of 2.5 kt/yr and 0.2 kt/yr at the end of 2009.

High-resolution diffusion tensor imaging of the human kidneys using a free-breathing, multi-slice, targeted field of view approach

PubMed Central

Chan, Rachel W; Von Deuster, Constantin; Stoeck, Christian T; Harmer, Jack; Punwani, Shonit; Ramachandran, Navin; Kozerke, Sebastian; Atkinson, David

2014-01-01

Fractional anisotropy (FA) obtained by diffusion tensor imaging (DTI) can be used to image the kidneys without any contrast media. FA of the medulla has been shown to correlate with kidney function. It is expected that higher spatial resolution would improve the depiction of small structures within the kidney. However, the achievement of high spatial resolution in renal DTI remains challenging as a result of respiratory motion and susceptibility to diffusion imaging artefacts. In this study, a targeted field of view (TFOV) method was used to obtain high-resolution FA maps and colour-coded diffusion tensor orientations, together with measures of the medullary and cortical FA, in 12 healthy subjects. Subjects were scanned with two implementations (dual and single kidney) of a TFOV DTI method. DTI scans were performed during free breathing with a navigator-triggered sequence. Results showed high consistency in the greyscale FA, colour-coded FA and diffusion tensors across subjects and between dual- and single-kidney scans, which have in-plane voxel sizes of 2 × 2 mm2 and 1.2 × 1.2 mm2, respectively. The ability to acquire multiple contiguous slices allowed the medulla and cortical FA to be quantified over the entire kidney volume. The mean medulla and cortical FA values were 0.38 ± 0.017 and 0.21 ± 0.019, respectively, for the dual-kidney scan, and 0.35 ± 0.032 and 0.20 ± 0.014, respectively, for the single-kidney scan. The mean FA between the medulla and cortex was significantly different (p < 0.001) for both dual- and single-kidney implementations. High-spatial-resolution DTI shows promise for improving the characterization and non-invasive assessment of kidney function. © 2014 The Authors. NMR in Biomedicine published by John Wiley & Sons, Ltd. PMID:25219683

High-resolution diffusion tensor imaging of the human kidneys using a free-breathing, multi-slice, targeted field of view approach.

PubMed

Chan, Rachel W; Von Deuster, Constantin; Stoeck, Christian T; Harmer, Jack; Punwani, Shonit; Ramachandran, Navin; Kozerke, Sebastian; Atkinson, David

2014-11-01

Fractional anisotropy (FA) obtained by diffusion tensor imaging (DTI) can be used to image the kidneys without any contrast media. FA of the medulla has been shown to correlate with kidney function. It is expected that higher spatial resolution would improve the depiction of small structures within the kidney. However, the achievement of high spatial resolution in renal DTI remains challenging as a result of respiratory motion and susceptibility to diffusion imaging artefacts. In this study, a targeted field of view (TFOV) method was used to obtain high-resolution FA maps and colour-coded diffusion tensor orientations, together with measures of the medullary and cortical FA, in 12 healthy subjects. Subjects were scanned with two implementations (dual and single kidney) of a TFOV DTI method. DTI scans were performed during free breathing with a navigator-triggered sequence. Results showed high consistency in the greyscale FA, colour-coded FA and diffusion tensors across subjects and between dual- and single-kidney scans, which have in-plane voxel sizes of 2 × 2 mm(2) and 1.2 × 1.2 mm(2) , respectively. The ability to acquire multiple contiguous slices allowed the medulla and cortical FA to be quantified over the entire kidney volume. The mean medulla and cortical FA values were 0.38 ± 0.017 and 0.21 ± 0.019, respectively, for the dual-kidney scan, and 0.35 ± 0.032 and 0.20 ± 0.014, respectively, for the single-kidney scan. The mean FA between the medulla and cortex was significantly different (p < 0.001) for both dual- and single-kidney implementations. High-spatial-resolution DTI shows promise for improving the characterization and non-invasive assessment of kidney function. © 2014 The Authors. NMR in Biomedicine published by John Wiley & Sons, Ltd.

Diffusion properties of NAA in human corpus callosum as studied with diffusion tensor spectroscopy.

PubMed

Upadhyay, Jaymin; Hallock, Kevin; Erb, Kelley; Kim, Dae-Shik; Ronen, Itamar

2007-11-01

In diffusion tensor imaging (DTI) the anisotropic movement of water is exploited to characterize microstructure. One confounding issue of DTI is the presence of intra- and extracellular components contributing to the measured diffusivity. This causes an ambiguity in determining the underlying cause of diffusion properties, particularly the fractional anisotropy (FA). In this study an intracellular constituent, N-acetyl aspartate (NAA), was used to probe intracellular diffusion, while water molecules were used to probe the combined intra- and extracellular diffusion. NAA and water diffusion measurements were made in anterior and medial corpus callosum (CC) regions, which are referred to as R1 and R2, respectively. FA(NAA) was found to be greater than FA(Water) in both CC regions, thus indicating a higher degree of anisotropy within the intracellular space in comparison to the combined intra- and extracellular spaces. A decreasing trend in the FA of NAA and water was observed between R1 and R2, while the radial diffusivity (RD) for both molecules increased. The increase in RD(NAA) is particularly significant, thus explaining the more significant decrease in FA(NAA) between the two regions. It is suggested that diffusion tensor spectroscopy of NAA can potentially be used to further characterize microscopic anatomic organization in white matter. Copyright 2007 Wiley-Liss, Inc.

The Impact of Sex, Puberty, and Hormones on White Matter Microstructure in Adolescents

PubMed Central

Herting, Megan M.; Maxwell, Emily C.; Irvine, Christy

2012-01-01

Background: During adolescence, numerous factors influence the organization of the brain. It is unclear what influence sex and puberty have on white matter microstructure, as well as the role that rapidly increasing sex steroids play. Methods: White matter microstructure was examined in 77 adolescents (ages 10–16) using diffusion tensor imaging. Multiple regression analyses were performed to examine the relationships between fractional anisotropy (FA) and mean diffusivity (MD) and sex, puberty, and their interaction, controlling for age. Follow-up analyses determined if sex steroids predicted microstructural characteristics in sexually dimorphic and pubertal-related white matter regions, as well as in whole brain. Results: Boys had higher FA in white matter carrying corticospinal, long-range association, and cortico-subcortical fibers, and lower MD in frontal and temporal white matter compared with girls. Pubertal development was related to higher FA in the insula, while a significant sex-by-puberty interaction was seen in superior frontal white matter. In boys, testosterone predicted white matter integrity in sexually dimorphic regions as well as whole brain FA, whereas estradiol showed a negative relationship with FA in girls. Conclusions: Sex differences and puberty uniquely relate to white matter microstructure in adolescents, which can partially be explained by sex steroids. PMID:22002939

Microstructural Changes to the Brain of Mice after Methamphetamine Exposure as Identified with Diffusion Tensor Imaging

PubMed Central

McKenna, Benjamin S.; Brown, Gregory G.; Archibald, Sarah; Scadeng, Miriam; Bussell, Robert; Kesby, James P.; Markou, Athina; Soontornniyomkij, Virawudh; Achim, Cristian; Semenova, Svetlana

2016-01-01

Methamphetamine (METH) is an addictive psychostimulant inducing neurotoxicity. Human magnetic resonance imaging and diffusion tensor imaging (DTI) of METH-dependent participants find various structural abnormities. Animal studies demonstrate immunohistochemical changes in multiple cellular pathways after METH exposure. Here, we characterized the long-term effects of METH on brain microstructure in mice exposed to an escalating METH binge regimen using in vivo DTI, a methodology directly translatable across species. Results revealed four patterns of differential fractional anisotropy (FA) and mean diffusivity (MD) response when comparing METH-exposed (n=14) to saline-treated mice (n=13). Compared to the saline group, METH-exposed mice demonstrated: 1) decreased FA with no change in MD [corpus callosum (posterior forceps), internal capsule (left), thalamus (medial aspects), midbrain], 2) increased MD with no change in FA [posterior isocortical regions, caudate-putamen, hypothalamus, cerebral peduncle, internal capsule (right)], 3) increased FA with decreased MD [frontal isocortex, corpus callosum (genu)], and 4) increased FA with no change or increased MD [hippocampi, amygdala, lateral thalamus]. MD was negatively associated with calbindin-1 in hippocampi and positively with dopamine transporter in caudate-putamen. These findings highlight distributed and differential METH effects within the brain suggesting several distinct mechanisms. Such mechanisms likely change brain tissue differentially dependent upon neural location. PMID:27000304

White matter tracts in first-episode psychosis: A DTI tractography study of the uncinate fasciculus

PubMed Central

Price, Gary; Cercignani, Mara; Parker, Geoffrey J.M.; Altmann, Daniel R.; Barnes, Thomas R.E.; Barker, Gareth J.; Joyce, Eileen M.; Ron, Maria A.

2008-01-01

A model of disconnectivity involving abnormalities in the cortex and connecting white matter pathways may explain the symptoms and cognitive abnormalities of schizophrenia. Recently, diffusion imaging tractography has made it possible to study white matter pathways in detail, and we present here a study of patients with first-episode psychosis using this technique. We studied the uncinate fasciculus (UF), the largest white matter tract that connects the frontal and temporal lobes, two brain regions significantly implicated in schizophrenia. Nineteen patients with first-episode schizophrenia and 23 controls were studied using a probabilistic tractography algorithm (PICo). Fractional anisotropy (FA) and probability of connection were obtained for every voxel in the tract, and the group means and distributions of these variables were compared. The spread of the FA distribution in the upper tail, as measured by the squared coefficient of variance (SCV), was reduced in the left UF in the patient group, indicating that the number of voxels with high FA values was reduced in the core of the tract and suggesting the presence of changes in fibre alignment and tract coherence in the patient group. The SCV of FA was lower in females across both groups and there was no correlation between the SCV of FA and clinical ratings. PMID:17988894

The role of abnormalities in the corpus callosum in social cognition deficits after Traumatic Brain Injury.

PubMed

McDonald, Skye; Rushby, Jacqueline A; Dalton, Katie I; Allen, Samantha K; Parks, Nicklas

2018-08-01

The corpus callosum (CC) is vulnerable to severe traumatic brain injury (TBI). Social cognition requires integration of non-verbal and verbal information in order to understand social behaviour and may be compromised if the CC is damaged. 17 adults with severe, chronic TBI and 17 control participants underwent structural MRI and Diffusion Tensor Imaging. A region of interest analysis examined fractional anisotropy (FA) and mean diffusivity (MD) across regions of the CC. Performance on The Awareness of Social Inference Test (TASIT): part 1 (emotion recognition) and parts 2 and 3 (social inference), was examined in relation to FA and MD. Across participants, higher genu FA values were related to higher TASIT part 3 scores. Increased splenium FA was associated with better performance for TASIT parts 1-3. There was no association between DTI values and TASIT in the controls alone. In the TBI group, FA of the genu and splenium was correlated with TASIT part 3. The pattern of performance was similar when controlling for non-social cognitive ability. In conclusion, social information is complex and multi-modal requiring inter-hemispheric connection. People with TBI, regardless of focal grey matter injury, may lose social cognitive ability due to trauma related changes to the corpus callosum.

Oxidative stability of sunflower oil supplemented with medicinal split gill mushroom, Schizophyllum commune Fr.:Fr. extract during accelerated storage.

PubMed

Yim, Hip Seng; Chye, Fook Yee; Heng, Pei Ying; Ho, Chun Wai

2011-01-01

The oxidative stability of sunflower oil supplemented with medicinal split gill mushroom, Schizophyllum commune's crude extract (CE), the formic acid (FA) fraction and semipurified subfractions (SF) II and IV were tested, compared to BHA and alpha-tocopherol, by measuring their peroxide value, iodine value, p-anisidine value, thiobarbituric acid-reactive substances, and free fatty acid content. Their total phenolic content (TPC), 2,2-diphenyl-1-picryhydrazyl (DPPH) radical scavenging, and ferric reducing/antioxidant power (FRAP) were also evaluated. FA and CE exhibited highest DPPH* scavenging, while FA and SFIV showed the highest FRAP; TPC was found to be highest in CE, FA, and SFIV. BHA and alpha-tocopherol are more protective in stabilizing the sunflower oil; SFII and SFIV had short-term protective effect in secondary oxidation for 1 year, while CE and FA retarded secondary oxidation and extended the shelf life 1 1/2 years and 2 years, respectively. HPLC-DAD analysis found (+)-catechin in Sch. commune's extracts. Sch. commune's extracts did not show similar retardation of lipid oxidation in sunflower oil as compared to alpha-tocopherol and BHA at the 200 ppm level. However, the higher concentration of Sch. commune's extract that provided the protective effect in stabilizing sunflower oil can be further studied.

Model-Based Radiation Dose Correction for Yttrium-90 Microsphere Treatment of Liver Tumors With Central Necrosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Ching-Sheng; Department of Nuclear Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; Lin, Ko-Han

Purpose: The objectives of this study were to model and calculate the absorbed fraction {phi} of energy emitted from yttrium-90 ({sup 90}Y) microsphere treatment of necrotic liver tumors. Methods and Materials: The tumor necrosis model was proposed for the calculation of {phi} over the spherical shell region. Two approaches, the semianalytic method and the probabilistic method, were adopted. In the former method, the range--energy relationship and the sampling of electron paths were applied to calculate the energy deposition within the target region, using the straight-ahead and continuous-slowing-down approximation (CSDA) method. In the latter method, the Monte Carlo PENELOPE code wasmore » used to verify results from the first method. Results: The fraction of energy, {phi}, absorbed from {sup 90}Y by 1-cm thickness of tumor shell from microsphere distribution by CSDA with complete beta spectrum was 0.832 {+-} 0.001 and 0.833 {+-} 0.001 for smaller (r{sub T} = 5 cm) and larger (r{sub T} = 10 cm) tumors (where r is the radii of the tumor [T] and necrosis [N]). The fraction absorbed depended mainly on the thickness of the tumor necrosis configuration, rather than on tumor necrosis size. The maximal absorbed fraction {phi} that occurred in tumors without central necrosis for each size of tumor was different: 0.950 {+-} 0.000, and 0.975 {+-} 0.000 for smaller (r{sub T} = 5 cm) and larger (r{sub T} = 10 cm) tumors, respectively (p < 0.0001). Conclusions: The tumor necrosis model was developed for dose calculation of {sup 90}Y microsphere treatment of hepatic tumors with central necrosis. With this model, important information is provided regarding the absorbed fraction applicable to clinical {sup 90}Y microsphere treatment.« less

A voxel-based mouse for internal dose calculations using Monte Carlo simulations (MCNP).

PubMed

Bitar, A; Lisbona, A; Thedrez, P; Sai Maurel, C; Le Forestier, D; Barbet, J; Bardies, M

2007-02-21

Murine models are useful for targeted radiotherapy pre-clinical experiments. These models can help to assess the potential interest of new radiopharmaceuticals. In this study, we developed a voxel-based mouse for dosimetric estimates. A female nude mouse (30 g) was frozen and cut into slices. High-resolution digital photographs were taken directly on the frozen block after each section. Images were segmented manually. Monoenergetic photon or electron sources were simulated using the MCNP4c2 Monte Carlo code for each source organ, in order to give tables of S-factors (in Gy Bq-1 s-1) for all target organs. Results obtained from monoenergetic particles were then used to generate S-factors for several radionuclides of potential interest in targeted radiotherapy. Thirteen source and 25 target regions were considered in this study. For each source region, 16 photon and 16 electron energies were simulated. Absorbed fractions, specific absorbed fractions and S-factors were calculated for 16 radionuclides of interest for targeted radiotherapy. The results obtained generally agree well with data published previously. For electron energies ranging from 0.1 to 2.5 MeV, the self-absorbed fraction varies from 0.98 to 0.376 for the liver, and from 0.89 to 0.04 for the thyroid. Electrons cannot be considered as 'non-penetrating' radiation for energies above 0.5 MeV for mouse organs. This observation can be generalized to radionuclides: for example, the beta self-absorbed fraction for the thyroid was 0.616 for I-131; absorbed fractions for Y-90 for left kidney-to-left kidney and for left kidney-to-spleen were 0.486 and 0.058, respectively. Our voxel-based mouse allowed us to generate a dosimetric database for use in preclinical targeted radiotherapy experiments.

Environmental controls on the 2H/1H values of terrestrial leaf waxes in the eastern Canadian Arctic

NASA Astrophysics Data System (ADS)

Shanahan, Timothy M.; Hughen, Konrad A.; Ampel, Linda; Sauer, Peter E.; Fornace, Kyrstin

2013-10-01

The hydrogen isotope composition of plant waxes preserved in lacustrine sediments is a potentially valuable tool for reconstructing paleoenvironmental changes in the Arctic. However, in contrast to the mid- and low-latitudes, significantly less effort has been directed towards understanding the factors controlling D/H fractionation in high latitude plant waxes and the impact of these processes on the interpretation of sedimentary leaf wax δD records. To better understand these processes, we examined the D/H ratios of long chain fatty acids in lake surface sediments spanning a temperature and precipitation gradient on Baffin Island in the eastern Canadian Arctic. D/H ratios of plant waxes increase with increasing temperature and aridity, with values ranging from -240‰ to -160‰ over the study area. Apparent fractionation factors between n-alkanoic acids in Arctic lake sediments and precipitation(εFA-ppt) are less negative than those of mid-latitude lakes and modern plants by 25‰ to 65‰, consistent with n-alkane data from modern Arctic plants (Yang et al., 2011). Furthermore, εFA-ppt values from Arctic lakes become systematically more positive with increasing evaporation, in contrast to mid-latitude sites, which show little to no change in fractionation with aridity. These data are consistent with enhanced water loss and isotope fractionation at higher latitude in the Arctic summer, when continuous sunlight supports increased daily photosynthesis. The dominant control on δDFA variations on Baffin Island is temperature. However, changing εFA-ppt result in steeper δDFA-temperature relationships than observed for modern precipitation. The application of this δDFA-based paleotemperature calibration to existing δDFA records from Baffin Island produces much more realistic changes in late Holocene temperature and highlights the importance of these effects in influencing the interpretation of Arctic δDFA records. A better understanding of the controls on hydrogen isotope fractionation in high latitude leaf waxes will be essential to the proper interpretation of isotope records from sedimentary plant waxes in the Arctic.

Mechanical Properties and Shear Strengthening Capacity of High Volume Fly Ash-Cementitious Composite

NASA Astrophysics Data System (ADS)

Joseph, Aswin K.; Anand, K. B.

2018-02-01

This paper discusses development of Poly Vinyl Alcohol (PVA) fibre reinforced cementitious composites taking into account environmental sustainability. Composites with fly ash to cement ratios from 0 to 3 are investigated in this study. The mechanical properties of HVFA-cement composite are discussed in this paper at PVA fiber volume fraction maintained at 1% of total volume of composite. The optimum replacement of cement with fly ash was found to be 75%, i.e. fly ash to cement ratio (FA/C) of 3. The increase in fiber content from 1% to 2% showed better mechanical performance. A strain capacity of 2.38% was obtained for FA/C ratio of 3 with 2% volume fraction of fiber. With the objective of evaluating the performance of cementitious composites as a strengthening material in reinforced concrete beams, the beams deficient in shear capacity were strengthened with optimal mix having 2% volume fraction of fiber as the strengthening material and tested under four-point load. The reinforced concrete beams designed as shear deficient were loaded to failure and retrofitted with the composite in order to assess the efficiency as a repair material under shear.

Effect of selenium-enriched organic material amendment on selenium fraction transformation and bioavailability in soil.

PubMed

Wang, Dan; Dinh, Quang Toan; Anh Thu, Tran Thi; Zhou, Fei; Yang, Wenxiao; Wang, Mengke; Song, Weiwei; Liang, Dongli

2018-05-01

To exploit the plant byproducts from selenium (Se) biofortification and reduce environmental risk of inorganic Se fertilizer, pot experiment was conducted in this study. The effects of Se-enriched wheat (Triticum aestivum L.) straw (WS + Se) and pak choi (Brassica chinensis L.) (P + Se) amendment on organo-selenium speciation transformation in soil and its bioavailability was evaluated by pak choi uptake. The Se contents of the cultivated pak choi in treatments amended with the same amount of Se-enriched wheat straw and pak choi were 1.7 and 9.7 times in the shoots and 2.3 and 6.3 times in the roots compared with control treatment. Soil respiration rate was significantly increased after all organic material amendment in soil (p < 0.05), which accelerated the mineralization of organic materials and thus resulted in soluble Se (SOL-Se), exchangeable Se (EX-Se), and fulvic acid-bound Se (FA-Se) fraction increasing by 25.2-29.2%, 9-13.8%, and 4.92-8.28%, respectively. In addition, both Pearson correlation and cluster analysis showed that EX-Se and FA-Se were better indicators for soil Se availability in organic material amendment soils. The Marquardt-Levenberg Model well described the dynamic kinetics of FA-Se content after Se-enriched organic material amendment in soil mainly because of the mineralization of organic carbon and organo-selenium. The utilization of Se in P + Se treatment was significantly higher than those in WS + Se treatment because of the different mineralization rates and the amount of FA-Se in soil. Se-enriched organic materials amendment can not only increase the availability of selenium in soil but also avoid the waste of valuable Se source. Copyright © 2018 Elsevier Ltd. All rights reserved.

A decision tree for differentiating multiple system atrophy from Parkinson's disease using 3-T MR imaging.

PubMed

Nair, Shalini Rajandran; Tan, Li Kuo; Mohd Ramli, Norlisah; Lim, Shen Yang; Rahmat, Kartini; Mohd Nor, Hazman

2013-06-01

To develop a decision tree based on standard magnetic resonance imaging (MRI) and diffusion tensor imaging to differentiate multiple system atrophy (MSA) from Parkinson's disease (PD). 3-T brain MRI and DTI (diffusion tensor imaging) were performed on 26 PD and 13 MSA patients. Regions of interest (ROIs) were the putamen, substantia nigra, pons, middle cerebellar peduncles (MCP) and cerebellum. Linear, volumetry and DTI (fractional anisotropy and mean diffusivity) were measured. A three-node decision tree was formulated, with design goals being 100 % specificity at node 1, 100 % sensitivity at node 2 and highest combined sensitivity and specificity at node 3. Nine parameters (mean width, fractional anisotropy (FA) and mean diffusivity (MD) of MCP; anteroposterior diameter of pons; cerebellar FA and volume; pons and mean putamen volume; mean FA substantia nigra compacta-rostral) showed statistically significant (P < 0.05) differences between MSA and PD with mean MCP width, anteroposterior diameter of pons and mean FA MCP chosen for the decision tree. Threshold values were 14.6 mm, 21.8 mm and 0.55, respectively. Overall performance of the decision tree was 92 % sensitivity, 96 % specificity, 92 % PPV and 96 % NPV. Twelve out of 13 MSA patients were accurately classified. Formation of the decision tree using these parameters was both descriptive and predictive in differentiating between MSA and PD. • Parkinson's disease and multiple system atrophy can be distinguished on MR imaging. • Combined conventional MRI and diffusion tensor imaging improves the accuracy of diagnosis. • A decision tree is descriptive and predictive in differentiating between clinical entities. • A decision tree can reliably differentiate Parkinson's disease from multiple system atrophy.

Amelioration of Head and Neck Radiation-Induced Mucositis and Distant Marrow Suppression in Fanca-/- and Fancg-/- Mice by Intraoral Administration of GS-Nitroxide (JP4-039).

PubMed

Willis, John; Epperly, Michael W; Fisher, Renee; Zhang, Xichen; Shields, Donna; Hou, Wen; Wang, Hong; Li, Song; Wipf, Peter; Parmar, Kalindi; Guinan, Eva; Steinman, Justin; Greenberger, Joel S

2018-06-01

Squamous cell carcinomas of the head and neck are appearing with increased frequency in both marrow transplanted and non-transplanted Fanconi anemia (FA) patients. FA patients commonly display radiosensitivity of epithelial tissues, complicating effective radiotherapy. Fancd2 -/- mice (C57BL/6J and 129/Sv background) demonstrate epithelial tissue sensitivity to single-fraction or fractionated irradiation to the head and neck and distant marrow suppression (abscopal effect), both ameliorated by intraoral administration of the mitochondrial-targeted antioxidant, GS-nitroxide, JP4-039. We now report that mice of two other FA genotypes, Fancg -/- (B6) and the most prevalent human genotype Fanca -/- (129/Sv), also demonstrate: 1. reduced longevity of hematopoiesis in long-term bone marrow cultures; 2. radiosensitivity of bone marrow stromal cell lines; and 3. head and neck radiation-induced severe mucositis and abscopal suppression of distant marrow hematopoiesis. Intraoral administration of JP4-039/F15, but not non-mitochondrial-targeted 4-amino-Tempo/F15 or F15 alone, prior to each radiation treatment ameliorated both local and abscopal radiation effects. Head and neck irradiated TGF-β-resistant SMAD3 -/- (129/Sv) mice and double-knockout SMAD3 -/- Fancd2 -/- (129/Sv) mice treated daily with TGF-β receptor antagonist, LY364947, still displayed abscopal bone marrow suppression, implicating a non-TGF-β mechanism. Thus, amelioration of both local normal tissue radiosensitivity and distant marrow suppression by intraoral administration of JP4-039 in Fancg -/- and Fanca -/- mice supports a clinical trial of this locally administered normal tissue radioprotector and mitigator during head and neck irradiation in FA patients.

Change-point analysis data of neonatal diffusion tensor MRI in preterm and term-born infants.

PubMed

Wu, Dan; Chang, Linda; Akazawa, Kentaro; Oishi, Kumiko; Skranes, Jon; Ernst, Thomas; Oishi, Kenichi

2017-06-01

The data presented in this article are related to the research article entitled "Mapping the Critical Gestational Age at Birth that Alters Brain Development in Preterm-born Infants using Multi-Modal MRI" (Wu et al., 2017) [1]. Brain immaturity at birth poses critical neurological risks in the preterm-born infants. We used a novel change-point model to analyze the critical gestational age at birth (GAB) that could affect postnatal development, based on diffusion tensor MRI (DTI) acquired from 43 preterm and 43 term-born infants in 126 brain regions. In the corresponding research article, we presented change-point analysis of fractional anisotropy (FA) and mean diffusivities (MD) measurements in these infants. In this article, we offered the relative changes of axonal and radial diffusivities (AD and RD) in relation to the change of FA and FA-based change-points, and we also provided the AD- and RD-based change-point results.

White Matter Changes and Confrontation Naming in Retired Aging National Football League Athletes.

PubMed

Strain, Jeremy F; Didehbani, Nyaz; Spence, Jeffrey; Conover, Heather; Bartz, Elizabeth K; Mansinghani, Sethesh; Jeroudi, Myrtle K; Rao, Neena K; Fields, Lindy M; Kraut, Michael A; Cullum, C Munro; Hart, John; Womack, Kyle B

2017-01-15

Using diffusion tensor imaging (DTI), we assessed the relationship of white matter integrity and performance on the Boston Naming Test (BNT) in a group of retired professional football players and a control group. We examined correlations between fractional anisotropy (FA) and mean diffusivity (MD) with BNT T-scores in an unbiased voxelwise analysis processed with tract-based spatial statistics (TBSS). We also analyzed the DTI data by grouping voxels together as white matter tracts and testing each tract's association with BNT T-scores. Significant voxelwise correlations between FA and BNT performance were only seen in the retired football players (p < 0.02). Two tracts had mean FA values that significantly correlated with BNT performance: forceps minor and forceps major. White matter integrity is important for distributed cognitive processes, and disruption correlates with diminished performance in athletes exposed to concussive and subconcussive brain injuries, but not in controls without such exposure.

Relationship between symptom dimensions and white matter alterations in obsessive-compulsive disorder.

PubMed

Yagi, Michiyo; Hirano, Yoshiyuki; Nakazato, Michiko; Nemoto, Kiyotaka; Ishikawa, Kazuhiro; Sutoh, Chihiro; Miyata, Haruko; Matsumoto, Junko; Matsumoto, Koji; Masuda, Yoshitada; Obata, Takayuki; Iyo, Masaomi; Shimizu, Eiji; Nakagawa, Akiko

2017-06-01

To investigate the relationship between the severities of symptom dimensions in obsessive-compulsive disorder (OCD) and white matter alterations. We applied tract-based spatial statistics for diffusion tensor imaging (DTI) acquired by 3T magnetic resonance imaging. First, we compared fractional anisotropy (FA) between 20 OCD patients and 30 healthy controls (HC). Then, applying whole brain analysis, we searched the brain regions showing correlations between the severities of symptom dimensions assessed by Obsessive-Compulsive Inventory-Revised and FA in all participants. Finally, we calculated the correlations between the six symptom dimensions and multiple DTI measures [FA, axial diffusivity (AD), radial diffusivity (RD), mean diffusivity (MD)] in a region-of-interest (ROI) analysis and explored the differences between OCD patients and HC. There were no between-group differences in FA or brain region correlations between the severities of symptom dimensions and FA in any of the participants. ROI analysis revealed negative correlations between checking severity and left inferior frontal gyrus white matter and left middle temporal gyrus white matter and a positive correlation between ordering severity and right precuneus in FA in OCD compared with HC. We also found negative correlations between ordering severity and right precuneus in RD, between obsessing severities and right supramarginal gyrus in AD and MD, and between hoarding severity and right insular gyrus in AD. Our study supported the hypothesis that the severities of respective symptom dimensions are associated with different patterns of white matter alterations.

Tract-based analysis of white matter integrity in psychotic and nonpsychotic bipolar disorder.

PubMed

Ji, Andrew; Godwin, Douglass; Rutlin, Jerrel; Kandala, Sridhar; Shimony, Joshua S; Mamah, Daniel

2017-02-01

At least 50% of individuals with bipolar disorder (BD) present with psychosis during their lifetime. Psychotic symptoms have sometimes been linked to specific genetic and phenotypic markers. This study aims to explore potential differences between bipolar disorder subtypes by measuring white matter integrity of the brain and relationships with clinical measures. Diffusion tensor imaging and clinical measures were acquired from 102 participants, grouped as psychotic bipolar disorder (PBD) (n=48), non-psychotic bipolar disorder (NBD) (n=24), and healthy controls (n=30). We utilized a powerful, automated tool (TRACULA: Tracts Constrained by Underlying Anatomy) to analyze the fractional anisotropy (FA) and mean diffusivity (MD) of 18 white matter tracts. Decreased FA in numerous tracts was observed in bipolar disorder groups compared to healthy controls: bilateral cingulum-cingulate gyrus bundles, corticospinal tracts, and superior longitudinal fasciculi as well as the right hemisphere cingulum-angular bundle. Only left uncinate fasciculus FA differed between PBD and NPBD groups. We found no group differences in MD. Positive symptoms correlated with FA in the superior (inversely) and inferior (directly) longitudinal fasciculi. Negative symptoms directly correlated with mean FA of the corticospinal tract and cingulum-angular bundle. Neurotropic, mood-stabilizing medication prescribed for individuals with BD may interact with measures of white matter integrity in our BD participants. Our results indicate decreased white matter coherence in BD. Minimal differences in white matter FA between PBD and NPBD participants suggest related underlying neurobiology. Copyright © 2016 Elsevier B.V. All rights reserved.

Diffusion tensor imaging of anterior commissural fibers in patients with schizophrenia.

PubMed

Choi, Hongyoon; Kubicki, Marek; Whitford, Thomas J; Alvarado, Jorge L; Terry, Douglas P; Niznikiewicz, Margaret; McCarley, Robert W; Kwon, Jun Soo; Shenton, Martha E

2011-08-01

Alterations in white matter connections in schizophrenia have been investigated using diffusion tensor imaging (DTI). There is also evidence from post-mortem studies as well as from magnetic resonance imaging morphometry studies that the anterior commissure (AC) might be implicated in schizophrenia, but no studies, to date, have investigated the AC using DTI or tractography. DTI scans were analyzed from 25 patients and 23 controls. Mean fractional anisotropy (FA) and trace were measured from the AC tracts. SANS and SAPS were used to evaluate clinical symptoms, and the Iowa Gambling Task, related to decision making, was also examined. Results revealed a significant decrease in mean FA and a significant increase in mean trace of AC tracts in patients compared with controls. In addition, patients, but not controls, showed a negative correlation between age and AC integrity. Statistically significant positive correlations were also found between AC FA and total positive symptom score. Decision making was negatively correlated with FA in patients on the Iowa Gambling Task, but not in controls. This study provides quantitative evidence for a reduction of interhemispheric connectivity in schizophrenia within the AC. Negative correlation between age and AC FA in the patients is consistent with the idea that schizophrenia may be a disorder of white matter maturation. Positive correlation between FA and positive symptom is discussed in the context of white matter's established role in modulating neural conduction velocity. Published by Elsevier B.V.

White matter microstructural changes in adolescent anorexia nervosa including an exploratory longitudinal study.

PubMed

Vogel, Katja; Timmers, Inge; Kumar, Vinod; Nickl-Jockschat, Thomas; Bastiani, Matteo; Roebroek, Alard; Herpertz-Dahlmann, Beate; Konrad, Kerstin; Goebel, Rainer; Seitz, Jochen

2016-01-01

Anorexia nervosa (AN) often begins in adolescence, however, the understanding of the underlying pathophysiology at this developmentally important age is scarce, impeding early interventions. We used diffusion tensor imaging (DTI) to investigate microstructural white matter (WM) brain changes including an experimental longitudinal follow-up. We acquired whole brain diffusion-weighted brain scans of 22 adolescent female hospitalized patients with AN at admission and nine patients longitudinally at discharge after weight rehabilitation. Patients (10-18 years) were compared to 21 typically developing controls (TD). Tract-based spatial statistics (TBSS) were applied to compare fractional anisotropy (FA) across groups and time points. Associations between average FA values of the global WM skeleton and weight as well as illness duration parameters were analyzed by multiple linear regression. We observed increased FA in bilateral frontal, parietal and temporal areas in AN patients at admission compared to TD. Higher FA of the global WM skeleton at admission was associated with faster weight loss prior to admission. Exploratory longitudinal analysis showed this FA increase to be partially normalized after weight rehabilitation. Our findings reveal a markedly different pattern of WM microstructural changes in adolescent AN compared to most previous results in adult AN. This could signify a different susceptibility and reaction to semi-starvation in the still developing brain of adolescents or a time-dependent pathomechanism differing with extend of chronicity. Higher FA at admission in adolescents with AN could point to WM fibers being packed together more closely.

Loss of Dependence on Continued Expression of the Human Papillomavirus 16 E7 Oncogene in Cervical Cancers and Precancerous Lesions Arising in Fanconi Anemia Pathway-Deficient Mice

PubMed Central

Park, Soyeong; Park, Jung Wook; Pitot, Henry C.

2016-01-01

ABSTRACT   Fanconi anemia (FA) is a rare genetic disorder caused by defects in DNA damage repair. FA patients often develop squamous cell carcinoma (SCC) at sites where high-risk human papillomaviruses (HPVs) are known to cause cancer, including the cervix. However, SCCs found in human FA patients are often HPV negative, even though the majority of female FA patients with anogenital cancers had preexisting HPV-positive dysplasia. We hypothesize that HPVs contribute to the development of SCCs in FA patients but that the continued expression of HPV oncogenes is not required for the maintenance of the cancer state because FA deficiency leads to an accumulation of mutations in cellular genes that render the cancer no longer dependent upon viral oncogenes. We tested this hypothesis, making use of Bi-L E7 transgenic mice in which we temporally controlled expression of HPV16 E7, the dominant viral oncogene in HPV-associated cancers. As seen before, the persistence of cervical neoplastic disease was highly dependent upon the continued expression of HPV16 E7 in FA-sufficient mice. However, in mice with FA deficiency, cervical cancers persisted in a large fraction of the mice after HPV16 E7 expression was turned off, indicating that these cancers had escaped from their dependency on E7. Furthermore, the severity of precancerous lesions also failed to be reduced significantly in the mice with FA deficiency upon turning off expression of E7. These findings confirm our hypothesis and may explain the fact that, while FA patients have a high frequency of infections by HPVs and HPV-induced precancerous lesions, the cancers are frequently HPV negative. Importance   Fanconi anemia (FA) patients are at high risk for developing squamous cell carcinoma (SCC) at sites where high-risk human papillomaviruses (HPVs) frequently cause cancer. Yet these SCCs are often HPV negative. FA patients have a genetic defect in their capacity to repair damaged DNA. HPV oncogenes cause an accumulation of DNA damage. We hypothesize, therefore, that DNA damage induced by HPV leads to an accumulation of mutations in patients with FA deficiency and that such mutations allow HPV-driven cancers to become independent of the viral oncogenes. Consistent with this hypothesis, we found that cervical cancers arising in HPV16 transgenic mice with FA deficiency frequently escape from dependency on the HPV16 oncogene that drove its development. Our report provides further support for vaccination of FA patients against HPVs and argues for the need to define mutational profiles of SCCs arising in FA patients in order to inform precision medicine-based approaches to treating these patients. PMID:27190216

Loss of Dependence on Continued Expression of the Human Papillomavirus 16 E7 Oncogene in Cervical Cancers and Precancerous Lesions Arising in Fanconi Anemia Pathway-Deficient Mice.

PubMed

Park, Soyeong; Park, Jung Wook; Pitot, Henry C; Lambert, Paul F

2016-05-17

Fanconi anemia (FA) is a rare genetic disorder caused by defects in DNA damage repair. FA patients often develop squamous cell carcinoma (SCC) at sites where high-risk human papillomaviruses (HPVs) are known to cause cancer, including the cervix. However, SCCs found in human FA patients are often HPV negative, even though the majority of female FA patients with anogenital cancers had preexisting HPV-positive dysplasia. We hypothesize that HPVs contribute to the development of SCCs in FA patients but that the continued expression of HPV oncogenes is not required for the maintenance of the cancer state because FA deficiency leads to an accumulation of mutations in cellular genes that render the cancer no longer dependent upon viral oncogenes. We tested this hypothesis, making use of Bi-L E7 transgenic mice in which we temporally controlled expression of HPV16 E7, the dominant viral oncogene in HPV-associated cancers. As seen before, the persistence of cervical neoplastic disease was highly dependent upon the continued expression of HPV16 E7 in FA-sufficient mice. However, in mice with FA deficiency, cervical cancers persisted in a large fraction of the mice after HPV16 E7 expression was turned off, indicating that these cancers had escaped from their dependency on E7. Furthermore, the severity of precancerous lesions also failed to be reduced significantly in the mice with FA deficiency upon turning off expression of E7. These findings confirm our hypothesis and may explain the fact that, while FA patients have a high frequency of infections by HPVs and HPV-induced precancerous lesions, the cancers are frequently HPV negative. IMPORTANCE  : Fanconi anemia (FA) patients are at high risk for developing squamous cell carcinoma (SCC) at sites where high-risk human papillomaviruses (HPVs) frequently cause cancer. Yet these SCCs are often HPV negative. FA patients have a genetic defect in their capacity to repair damaged DNA. HPV oncogenes cause an accumulation of DNA damage. We hypothesize, therefore, that DNA damage induced by HPV leads to an accumulation of mutations in patients with FA deficiency and that such mutations allow HPV-driven cancers to become independent of the viral oncogenes. Consistent with this hypothesis, we found that cervical cancers arising in HPV16 transgenic mice with FA deficiency frequently escape from dependency on the HPV16 oncogene that drove its development. Our report provides further support for vaccination of FA patients against HPVs and argues for the need to define mutational profiles of SCCs arising in FA patients in order to inform precision medicine-based approaches to treating these patients. Copyright © 2016 Park et al.

Alterations in the inferior longitudinal fasciculus in autism and associations with visual processing: a diffusion-weighted MRI study.

PubMed

Boets, Bart; Van Eylen, Lien; Sitek, Kevin; Moors, Pieter; Noens, Ilse; Steyaert, Jean; Sunaert, Stefan; Wagemans, Johan

2018-01-01

One of the most reported neural features of autism spectrum disorder (ASD) is the alteration of multiple long-range white matter fiber tracts, as assessed by diffusion-weighted imaging and indexed by reduced fractional anisotropy (FA). Recent methodological advances, however, have shown that this same pattern of reduced FA may be an artifact resulting from excessive head motion and poorer data quality and that aberrant structural connectivity in children with ASD is confined to the right inferior longitudinal fasciculus (ILF). This study aimed at replicating the observation of reduced FA along the right ILF in ASD, while controlling for group differences in head motion and data quality. In addition, we explored associations between reduced FA in the right ILF and quantitative ASD characteristics, and the involvement of the right ILF in visual processing, which is known to be altered in ASD. Global probabilistic tractography was performed on diffusion-weighted imaging data of 17 adolescent boys with ASD and 17 typically developing boys, matched for age, performance IQ, handedness, and data quality. Four tasks were administered to measure various aspects of visual information processing, together with questionnaires assessing ASD characteristics. Group differences were examined and the neural data were integrated with previously published findings using Bayesian statistics to quantify evidence for replication and to pool data and thus increase statistical power. (Partial) correlations were calculated to investigate associations between measures. The ASD group showed consistently reduced FA only in the right ILF and slower performance on the visual search task. Bayesian statistics pooling data across studies confirmed that group differences in FA were confined to the right ILF only, with the evidence for altered FA in the left ILF being indecisive. Lower FA in the right ILF tended to covary with slower visual search and a more fragmented part-oriented processing style. Individual differences in FA of the right ILF were not reliably associated with the severity of ASD traits after controlling for clinical status. Our findings support the growing evidence for reduced FA along a specific fiber tract in ASD, the right ILF.

Enhanced photovoltaic performance and stability with a new type of hollow 3D perovskite {en}FASnI 3

DOE PAGES

Ke, Weijun; Stoumpos, Constantinos C.; Zhu, Menghua; ...

2017-08-30

Perovskite solar cells have revolutionized the fabrication of solution-processable solar cells. The presence of lead in the devices makes this technology less attractive, and alternative metals in perovskites are being researched as suitable alternatives. We demonstrate a new type of tin-based perovskite absorber that incorporates both ethylenediammonium (en) and formamidinium (FA), forming new materials of the type {en}FASnI 3. The three-dimensional ASnI 3 structure is stable only with methylammonium, FA, and Cs cations, and the bandgap can be tuned with solid solutions, such as ASnI 3-xBr x. We show that en can serve as a new A cation capable ofmore » achieving marked increases in the bandgap without the need for solid solutions. The en introduces a new bandgap tuning mechanism that arises from massive Schottky style defects. In addition, incorporation of the en cation in the structure markedly increases the air stability and improves the photoelectric properties of the tin-based perovskite absorbers. Our best-performing {en}FASnI 3 solar cell has the highest efficiency of 7.14%, which is achieved for a lead-free perovskite cell, and retains 96% of its initial efficiency after aging over 1000 hours with encapsulation. Our results introduce a new approach for improving the performance and stability of tin-based, lead-free perovskite solar cells.« less

Enhanced photovoltaic performance and stability with a new type of hollow 3D perovskite {en}FASnI 3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ke, Weijun; Stoumpos, Constantinos C.; Zhu, Menghua

Perovskite solar cells have revolutionized the fabrication of solution-processable solar cells. The presence of lead in the devices makes this technology less attractive, and alternative metals in perovskites are being researched as suitable alternatives. We demonstrate a new type of tin-based perovskite absorber that incorporates both ethylenediammonium (en) and formamidinium (FA), forming new materials of the type {en}FASnI 3. The three-dimensional ASnI 3 structure is stable only with methylammonium, FA, and Cs cations, and the bandgap can be tuned with solid solutions, such as ASnI 3-xBr x. We show that en can serve as a new A cation capable ofmore » achieving marked increases in the bandgap without the need for solid solutions. The en introduces a new bandgap tuning mechanism that arises from massive Schottky style defects. In addition, incorporation of the en cation in the structure markedly increases the air stability and improves the photoelectric properties of the tin-based perovskite absorbers. Our best-performing {en}FASnI 3 solar cell has the highest efficiency of 7.14%, which is achieved for a lead-free perovskite cell, and retains 96% of its initial efficiency after aging over 1000 hours with encapsulation. Our results introduce a new approach for improving the performance and stability of tin-based, lead-free perovskite solar cells.« less

Enhanced photovoltaic performance and stability with a new type of hollow 3D perovskite {en}FASnI3

PubMed Central

Ke, Weijun; Stoumpos, Constantinos C.; Zhu, Menghua; Mao, Lingling; Spanopoulos, Ioannis; Liu, Jian; Kontsevoi, Oleg Y.; Chen, Michelle; Sarma, Debajit; Zhang, Yongbo; Wasielewski, Michael R.; Kanatzidis, Mercouri G.

2017-01-01

Perovskite solar cells have revolutionized the fabrication of solution-processable solar cells. The presence of lead in the devices makes this technology less attractive, and alternative metals in perovskites are being researched as suitable alternatives. We demonstrate a new type of tin-based perovskite absorber that incorporates both ethylenediammonium (en) and formamidinium (FA), forming new materials of the type {en}FASnI3. The three-dimensional ASnI3 structure is stable only with methylammonium, FA, and Cs cations, and the bandgap can be tuned with solid solutions, such as ASnI3−xBrx. We show that en can serve as a new A cation capable of achieving marked increases in the bandgap without the need for solid solutions. The en introduces a new bandgap tuning mechanism that arises from massive Schottky style defects. In addition, incorporation of the en cation in the structure markedly increases the air stability and improves the photoelectric properties of the tin-based perovskite absorbers. Our best-performing {en}FASnI3 solar cell has the highest efficiency of 7.14%, which is achieved for a lead-free perovskite cell, and retains 96% of its initial efficiency after aging over 1000 hours with encapsulation. Our results introduce a new approach for improving the performance and stability of tin-based, lead-free perovskite solar cells. PMID:28875173

Changes in Soil Microbial Community and Its Effect on Carbon Sequestration Following Afforestation on the Loess Plateau, China.

PubMed

Xiang, Yun; Cheng, Man; Huang, Yimei; An, Shaoshan; Darboux, Frédéric

2017-08-22

Afforestation plays an important role in soil protection and ecological restoration. The objective of this study is to understand the effect of afforestation on soil carbon and soil microbial communities in the Loess Plateau of China. We measured two chemically-separated carbon fractions (i.e., humic acid, HA, and fulvic acid, FA) and soil microbial communities within shrublands (18-year-old Caragana korshinskii Kom (shrubland I) and 28-year-old Caragana korshinskii Kom (shrubland II)) and cropland. The size and structure of the soil microbial community was measured by phospholipid fatty acid (PLFA) analysis. The analysis of C-fractions indicated that at a depth of 0-20 cm, FA-C concentration in shrubland I and shrubland II were 1.7 times that of cropland, while HA-C had similar values across all three sites. Total PLFAs, G⁺ (Gram positive) bacterial, G - (Gram negative) bacterial, and actinobacterial PLFAs were highest in shrubland II, followed by shrubland I and finally cropland. Fungal PLFAs were significantly higher in shrubland II compared to the other sites. Additionally, we found a high degree of synergy between main microbial groups (apart from fungi) with FA-C. We concluded that planting C. korshinskii in abandoned cropland could alter the size and structure of soil microbial community, with these changes being closely related to carbon sequestration and humus formation.

Changes in Soil Microbial Community and Its Effect on Carbon Sequestration Following Afforestation on the Loess Plateau, China

PubMed Central

Xiang, Yun; Huang, Yimei; An, Shaoshan; Darboux, Frédéric

2017-01-01

Afforestation plays an important role in soil protection and ecological restoration. The objective of this study is to understand the effect of afforestation on soil carbon and soil microbial communities in the Loess Plateau of China. We measured two chemically-separated carbon fractions (i.e., humic acid, HA, and fulvic acid, FA) and soil microbial communities within shrublands (18-year-old Caragana korshinskii Kom (shrubland I) and 28-year-old Caragana korshinskii Kom (shrubland II)) and cropland. The size and structure of the soil microbial community was measured by phospholipid fatty acid (PLFA) analysis. The analysis of C-fractions indicated that at a depth of 0–20 cm, FA-C concentration in shrubland I and shrubland II were 1.7 times that of cropland, while HA-C had similar values across all three sites. Total PLFAs, G+ (Gram positive) bacterial, G− (Gram negative) bacterial, and actinobacterial PLFAs were highest in shrubland II, followed by shrubland I and finally cropland. Fungal PLFAs were significantly higher in shrubland II compared to the other sites. Additionally, we found a high degree of synergy between main microbial groups (apart from fungi) with FA-C. We concluded that planting C. korshinskii in abandoned cropland could alter the size and structure of soil microbial community, with these changes being closely related to carbon sequestration and humus formation. PMID:28829374

Diffusion tensor imaging with tract-based spatial statistics reveals local white matter abnormalities in preterm infants.

PubMed

Anjari, Mustafa; Srinivasan, Latha; Allsop, Joanna M; Hajnal, Joseph V; Rutherford, Mary A; Edwards, A David; Counsell, Serena J

2007-04-15

Infants born preterm have a high incidence of neurodevelopmental impairment in later childhood, often associated with poorly defined cerebral white matter abnormalities. Diffusion tensor imaging quantifies the diffusion of water within tissues and can assess microstructural abnormalities in the developing preterm brain. Tract-based spatial statistics (TBSS) is an automated observer-independent method of aligning fractional anisotropy (FA) images from multiple subjects to allow groupwise comparisons of diffusion tensor imaging data. We applied TBSS to test the hypothesis that preterm infants have reduced fractional anisotropy in specific regions of white matter compared to term-born controls. We studied 26 preterm infants with no evidence of focal lesions on conventional magnetic resonance imaging (MRI) at term equivalent age and 6 healthy term-born control infants. We found that the centrum semiovale, frontal white matter and the genu of the corpus callosum showed significantly lower FA in the preterm group. Infants born at less than or equal to 28 weeks gestational age (n=11) displayed additional reductions in FA in the external capsule, the posterior aspect of the posterior limb of the internal capsule and the isthmus and middle portion of the body of the corpus callosum. This study demonstrates that TBSS provides an observer-independent method of identifying white matter abnormalities in the preterm brain at term equivalent age in the absence of focal lesions.

Changes in levels of cell wall constituents in wheat seedlings grown under continuous hypergravity conditions

NASA Astrophysics Data System (ADS)

Wakabayashi, K.; Soga, K.; Kamisaka, S.; Hoson, T.

Effects of continuous hypergravity stimuli on the amounts and composition of cell wall constituents were investigated in wheat shoots. Hypergravity (300 g) treatment for three days after germination increased the net amount of cell wall polysaccharides such as hemicellulose and cellulose, but reduced the shoot elongation. As a result, the amount of cell wall polysaccharides per unit length of shoot increased under hypergravity. The hemicellulose fraction contained polysaccharides in the middle and low molecular mass range (5 kDa-1 MDa) and increased in response to hypergravity. Also, the amounts of arabinose (Ara) and xylose (Xyl), the major sugar components of the hemicellulose fraction, increased under hypergravity conditions. In addition to wall polysaccharides, hypergravity increased the amounts of cell wall-bound phenolic acids, such as ferulic acid (FA) and diferulic acid (DFA). Furthermore, the activity of phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) was enhanced under hypergravity conditions. These results suggest that continuous hypergravity stimulates the synthesis of cell wall constituents, especially hemicellulosic arabinoxylans and cell wall-bound FA and DFA in wheat shoots. The increased PAL activity may promote the formation of FA and DFA. These changes in cell wall architecture may be involved in making rigid and tough cell walls under hypergravity conditions and thereby contribute to the ability of plant to sustain their structures against gravitational stimuli.

Antarctic Meteorite Newsletter, volume 6, number 2

NASA Technical Reports Server (NTRS)

1983-01-01

Meteorites from the 1981 and 1982 Antarctic collection are listed showing classification, weight, degree of weathering, degree of fractionation, % Fa, and % Fs. Physical and petrigraphic characteristics are described for 23 samples from the Allan Hills, Thiel Mountains, the Pecora Escarpment, and the Elephant Moraine locations.

Solubility of iron from combustion source particles in acidic media linked to iron speciation.

PubMed

Fu, Hongbo; Lin, Jun; Shang, Guangfeng; Dong, Wenbo; Grassian, Vichi H; Carmichael, Gregory R; Li, Yan; Chen, Jianmin

2012-10-16

In this study, iron solubility from six combustion source particles was investigated in acidic media. For comparison, a Chinese loess (CL) dust was also included. The solubility experiments confirmed that iron solubility was highly variable and dependent on particle sources. Under dark and light conditions, the combustion source particles dissolved faster and to a greater extent relative to CL. Oil fly ash (FA) yielded the highest soluble iron as compared to the other samples. Total iron solubility fractions measured in the dark after 12 h ranged between 2.9 and 74.1% of the initial iron content for the combustion-derived particles (Oil FA > biomass burning particles (BP) > coal FA). Ferrous iron represented the dominant soluble form of Fe in the suspensions of straw BP and corn BP, while total dissolved Fe presented mainly as ferric iron in the cases of oil FA, coal FA, and CL. Mössbauer measurements and TEM analysis revealed that Fe in oil FA was commonly presented as nanosized Fe(3)O(4) aggregates and Fe/S-rich particles. Highly labile source of Fe in corn BP could be originated from amorphous Fe form mixed internally with K-rich particles. However, Fe in coal FA was dominated by the more insoluble forms of both Fe-bearing aluminosilicate glass and Fe oxides. The data presented herein showed that iron speciation varies by source and is an important factor controlling iron solubility from these anthropogenic emissions in acidic solutions, suggesting that the variability of iron solubility from combustion-derived particles is related to the inherent character and origin of the aerosols themselves. Such information can be useful in improving our understanding on iron solubility from combustion aerosols when they undergo acidic processing during atmospheric transport.

Test-retest reliability of diffusion tensor imaging of the liver at 3.0 T.

PubMed

Girometti, Rossano; Maieron, Marta; Lissandrello, Giovanni; Bazzocchi, Massimo; Zuiani, Chiara

2015-06-01

This study was done to evaluate test-retest reliability of liver diffusion tensor imaging (LDTI). Ten healthy volunteers (median age 23 years) underwent two LDTI scans on a 3.0 T magnet during two imaging sessions separated by 2 weeks (session-1/-2, respectively). Fifteen gradient directions and b values of 0-1,000 s/mm(2) were used. Two radiologists in consensus assessed liver apparent diffusion coefficient (ADC) and fraction of anisotropy (FA) values on ADC and FA maps at four reference levels, namely: right upper level (RUL), right lower level (RLL), left upper level (LUL) and left lower level (LLL). We then assessed (a) whether ADC and FA values overlapped when measured on different levels within the same imaging session or between different imaging sessions; (b) the degree of variability on an intra-session and inter-session basis, respectively, using the coefficient of variation (CV). In sessions 1 and 2, the ADC/FA values were significantly larger in the left liver lobe (LUL/LLL) compared to right liver lobe (RUL/RLL) (p < 0.05/6). Intra-session CVs were 9.51 % (session 1) and 9.73 % (session 2) for ADC, and 12.93 % (session 1) and 11.82 % (session 2) for FA, respectively. When comparing RUL, RLL, LUL and LLL on an inter-session basis, CVs were 6.52, 8.20, 6.52 and 11.06 % for ADC, and 15.42, 15.80, 15.42 and 6.80 % for FA, respectively. LDTI provides consistent and repeatable measurements. However, since larger left lobe ADC/FA values can be attributed to artefacts, right lobe values should be considered the most reliable measurements of water diffusivity within the liver.

Antisense down-regulation of the strawberry β-galactosidase gene FaβGal4 increases cell wall galactose levels and reduces fruit softening

PubMed Central

Paniagua, Candelas; Blanco-Portales, Rosario; Barceló-Muñoz, Marta; García-Gago, Juan A.; Waldron, Keith W.; Quesada, Miguel A.; Muñoz-Blanco, Juan; Mercado, José A.

2016-01-01

Strawberry softening is characterized by an increase in the solubilization and depolymerization of pectins from cell walls. Galactose release from pectin side chains by β-galactosidase enzymes has been proposed as one reason for the increase in soluble pectins. A putative β-galactosidase gene, FaβGal4, has been identified using a custom-made oligonucleotide-based strawberry microarray platform. FaβGal4 was expressed mainly in the receptacle during fruit ripening, and was positively regulated by abscisic acid and negatively regulated by auxins. To ascertain the role of FaβGal4 in strawberry softening, transgenic plants containing an antisense sequence of this gene under the control of the CaMV35S promoter were generated. Phenotypic analyses were carried out in transgenic plants during three consecutive growing seasons, using non-transformed plants as control. Two out of nine independent transgenic lines yielded fruits that were 30% firmer than control at the ripe stage. FaβGal4 mRNA levels were reduced by 70% in ripe fruits from these selected transgenic lines, but they also showed significant silencing of FaβGal1, although the genes did not share significant similarity. These two transgenic lines also showed an increase in pectin covalently bound to the cell wall, extracted using Na2CO3. The amount of galactose in cell walls from transgenic fruits was 30% higher than in control; notably, the galactose increase was larger in the 1 M KOH fraction, which is enriched in hemicellulose. These results suggest that FaβGal4 participates in the solubilization of covalently bound pectins during ripening, reducing strawberry fruit firmness. PMID:26585222

Evaluation of Soft Tissue Sarcoma Tumors Electrical Conductivity Anisotropy Using Diffusion Tensor Imaging for Numerical Modeling on Electroporation.

PubMed

Ghazikhanlou-Sani, K; Firoozabadi, S M P; Agha-Ghazvini, L; Mahmoodzadeh, H

2016-06-01

There is many ways to assessing the electrical conductivity anisotropy of a tumor. Applying the values of tissue electrical conductivity anisotropy is crucial in numerical modeling of the electric and thermal field distribution in electroporation treatments. This study aims to calculate the tissues electrical conductivity anisotropy in patients with sarcoma tumors using diffusion tensor imaging technique. A total of 3 subjects were involved in this study. All of patients had clinically apparent sarcoma tumors at the extremities. The T1, T2 and DTI images were performed using a 3-Tesla multi-coil, multi-channel MRI system. The fractional anisotropy (FA) maps were performed using the FSL (FMRI software library) software regarding the DTI images. The 3D matrix of the FA maps of each area (tumor, normal soft tissue and bone/s) was reconstructed and the anisotropy matrix was calculated regarding to the FA values. The mean FA values in direction of main axis in sarcoma tumors were ranged between 0.475-0.690.  With assumption of isotropy of the electrical conductivity, the FA value of electrical conductivity at each X, Y and Z coordinate axes would be equal to 0.577. The gathered results showed that there is a mean error band of 20% in electrical conductivity, if the electrical conductivity anisotropy not concluded at the calculations. The comparison of FA values showed that there is a significant statistical difference between the mean FA value of tumor and normal soft tissues (P<0.05). DTI is a feasible technique for the assessment of electrical conductivity anisotropy of tissues.  It is crucial to quantify the electrical conductivity anisotropy data of tissues for numerical modeling of electroporation treatments.

Antisense down-regulation of the strawberry β-galactosidase gene FaβGal4 increases cell wall galactose levels and reduces fruit softening.

PubMed

Paniagua, Candelas; Blanco-Portales, Rosario; Barceló-Muñoz, Marta; García-Gago, Juan A; Waldron, Keith W; Quesada, Miguel A; Muñoz-Blanco, Juan; Mercado, José A

2016-02-01

Strawberry softening is characterized by an increase in the solubilization and depolymerization of pectins from cell walls. Galactose release from pectin side chains by β-galactosidase enzymes has been proposed as one reason for the increase in soluble pectins. A putative β-galactosidase gene, FaβGal4, has been identified using a custom-made oligonucleotide-based strawberry microarray platform. FaβGal4 was expressed mainly in the receptacle during fruit ripening, and was positively regulated by abscisic acid and negatively regulated by auxins. To ascertain the role of FaβGal4 in strawberry softening, transgenic plants containing an antisense sequence of this gene under the control of the CaMV35S promoter were generated. Phenotypic analyses were carried out in transgenic plants during three consecutive growing seasons, using non-transformed plants as control. Two out of nine independent transgenic lines yielded fruits that were 30% firmer than control at the ripe stage. FaβGal4 mRNA levels were reduced by 70% in ripe fruits from these selected transgenic lines, but they also showed significant silencing of FaβGal1, although the genes did not share significant similarity. These two transgenic lines also showed an increase in pectin covalently bound to the cell wall, extracted using Na2CO3. The amount of galactose in cell walls from transgenic fruits was 30% higher than in control; notably, the galactose increase was larger in the 1 M KOH fraction, which is enriched in hemicellulose. These results suggest that FaβGal4 participates in the solubilization of covalently bound pectins during ripening, reducing strawberry fruit firmness. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Magombedze - A new H-chondrite with light-dark structure

NASA Technical Reports Server (NTRS)

Macpherson, Glenn J.; Jarosewich, Eugene; Lowenstein, Peter

1993-01-01

Magombedze is a light-dark structured H-chondrite breccia that fell in Zimbabwe on July 2, 1990 at 15:30 GMT. White clasts are moderately shocked and have equilibrated mafic silicates (pyroxene Fs(16-18), olivine Fa(18-19)) together with clear optically-recognizable plagioclase of variable composition (An(9-13) found); chondrules are distinct but contain no trace of preserved glass. The darker surrounding material contains a higher proportion of fine-grained metal and sulfide than the white clasts, and many of its constituent grains show little evidence of shock. Mafic silicates in the dark lithology are distinctly less-equilibrated (pyroxene Fs(5-21), olivine Fa(11-20)) than those in the white clasts, and many chondrules preserve brown devitrified glass; some metamorphic plagioclase of variable composition (An(11-22) found) is present. Some monoclinic pyroxene occurs in both fractions, but it is relatively common in the dark fraction. The white clasts are classified as H5, and the enclosing dark material is H3-5.

Diffusion tensor imaging and magnetic resonance spectroscopy assessment of cancellous bone quality in femoral neck of healthy, osteopenic and osteoporotic subjects at 3T: Preliminary experience.

PubMed

Manenti, Guglielmo; Capuani, Silvia; Fanucci, Ezio; Assako, Elie Parfait; Masala, Salvatore; Sorge, Roberto; Iundusi, Riccardo; Tarantino, Umberto; Simonetti, Giovanni

2013-07-01

We assessed the potential of diffusion tensor imaging (DTI) in combination with proton magnetic resonance spectroscopy (1H-MRS), in cancellous bone quality evaluation of the femoral neck in postmenopausal women. DTI allows for non-invasive microarchitectural characterization of heterogeneous tissue. In this work we hypothesized that DTI parameters mean diffusivity (MD) and fractional anisotropy (FA) of bone marrow water, can provide information about microstructural changes that occur with the development of osteoporosis disease. Because osteoporosis is associated with increased bone marrow fat content, which in principal can alter DTI parameters, the goal of this study was to examine the potential of MD and FA, in combination with bone marrow fat fraction (FF), to discriminate between healthy, osteopenic and osteoporotic subjects, classified according to DXA criteria. Forty postmenopausal women (mean age, 68.7 years; range 52-81 years), underwent a Dual-energy X-ray absorptiometry (DXA) examination in femoral neck, to be classified as healthy (n=12), osteopenic (n=14) and osteoporotic (n=14) subjects. 1H-MRS and DTI (with b value=2500 s/mm2) of femoral neck were obtained in each subject at 3T. The study protocol was approved by local Ethics Committee. MD, FA, FF and MD/FF, FA/FF were obtained and compared among the three bone-density groups. One-way ANOVA with multiple comparisons Bonferroni test and Pearson correlation analysis were applied. Receiver operating characteristic (ROC) curve analysis was also performed. Reproducibility of DTI measures was satisfactory. CV was approximately 2%-3% for MD and 4%-5% for FA measurements. Moreover, no significant difference was found in both MD and FA measurements between two separate sessions (median 34 days apart) comprised of six healthy volunteers. FF was able to discriminate between healthy and osteoporotic subjects only. Conversely MD and FA were able to discriminate healthy from osteopenic and healthy from osteoporotic subjects, but they were not able to discriminate between osteopenic and osteoporotic patients. A significant correlation between MD and FF was observed in healthy group only. A moderate correlation was found between MD and T-score when all groups together are considered. No significant correlation was found between MD and T-score within groups. A significant positive correlation between FA and FF was found in both osteopenic and osteoporotic groups. Vice-versa no correlation between FA and FF was observed in healthy group. A high significant positive correlation was found between FA and T-score in all groups together, in healthy and in osteoporotic groups. MD/FF and FA/FF are characterized by a higher sensitivity and specificity compared to MD and FA in the discrimination between healthy, and osteoporotic subjects. MD/FF vs. FA/FF graph extracted from femoral neck, identify all healthy individuals according to DXA results. DTI-(1)H-MRS protocol performed in femoral neck seems to be highly sensitive and specific in identifying healthy subjects. A MR exam is more expensive when compared to a DXA investigation. However, even though DXA BMD evaluation has been the accepted standard for osteoporosis diagnosis, DXA result has a low predictive value on patients' risk for future fractures. Thus, new approaches for examining patients at risk for developing osteoporosis would be desirable. Preliminary results showed here suggest that future studies on a larger population based on DTI assessment in the femoral neck, in combination with 1H-MRS investigations, might allow screening of high-risk populations and the establishment of cut-off values of normality, with potential application of the method to single subjects. Copyright © 2013 Elsevier Inc. All rights reserved.

Transport and fate of Herbaspirillum chlorophenolicum FA1 in saturated porous media

NASA Astrophysics Data System (ADS)

Li, X.; Xu, H.; Wu, J.

2016-12-01

For the bioremediation of contaminated groundwater, sufficient dispersal of functional microorganisms is one of the most important factors that determine the remediation efficiency. There are extensive studies on the transport of microbes in porous media, while most of them focus on pathogenic bacteria and little attention has been given toward functional bacteria that being used in bioremediation process. Therefore, accurate knowledge of the mechanisms that govern the transport and distribution of such bacteria in groundwater is needed to develop efficient treatment techniques. Herbaspirillum chlorophenolicum FA1, a pure bacterial strain capable of absorbing heavy metals and degrading polycyclic aromatic hydrocarbons (PAHs), was selected as the representative functional bacterium in this study. A series of batch and column experiments were conducted to investigate the transport and deposition behavior of strain FA1 in saturated porous media. The effects of physical (grain size), chemical (ionic strength, humic acid), and biological factors (living/dead cells) were studied in detail. In addition, numerical simulations of breakthrough curve (BTC) data were also performed for information gathering. Results of this study could advance our understanding of functional bacteria transport and help to develop successful bioremediation strategies. This work was financially supported by the National Natural Science Foundation of China -Xinjiang Project (U1503282), the National Natural Science Foundation of China (41030746, 41102148), and the Natural Science Foundation of Jiangsu Province (BK20151385). Keywords: Herbaspirillum chlorophenolicum FA1, bacteria, porous media, transport, modeling

Recoveries of rat lymph FA after administration of specific structured 13C-TAG.

PubMed

Vistisen, Bodil; Mu, Huiling; Høy, Carl-Erik

2003-09-01

The potential of the specific structured TAG MLM [where M = caprylic acid (8:0) and L = linoleic acid (18:2n-6)] is the simultaneous delivery of energy and EFA. Compared with long-chain TAG (LLL), they may be more rapidly hydrolyzed and absorbed. This study examined the lymphatic recoveries of intragastrically administered L*L*L*, M*M*M*, ML*M, and ML*L* (where * = 13C-labeled FA) in rats. Lymph lipids were separated into lipid classes and analyzed by GC combustion isotope ratio MS. The recoveries of lymph TAG 18:2n-6 8 h after administration of L*L*L*, ML*M, and ML*L* were 38.6, 48.4, and 49.1%, respectively, whereas after 24 h the recoveries were approximately 50% in all experimental groups. The exogenous contribution to lymph TAG 18:2n-6 was approximately 80 and 60% at maximum absorption of the specific structured TAG and L*L*L*, respectively, 3-6 h after administration. The tendency toward more rapid recovery of exogenous long-chain FA following administration of specific structured TAG compared with long-chain TAG was probably due to fast hydrolysis. The lymphatic recovery of 8:0 was 2.2% 24 h after administration of M*M*M*. This minor lymphatic recovery of exogenous 8:0 was probably due to low stimulation of chylomicron formation. These results demonstrate tendencies toward faster lymphatic recovery of long-chain FA after administration of specific structured TAG compared with long-chain TAG.

Contribution of diffusion tensor imaging to delineation of gliomas and glioblastomas.

PubMed

Tropine, A; Vucurevic, G; Delani, P; Boor, S; Hopf, N; Bohl, J; Stoeter, P

2004-12-01

To determine if the diffusion tensor imaging (DTI) parameters fractional anisotropy (FA) and mean diffusivity (MD) can differentiate between accompanying edema and tumor cell infiltration of white matter (WM) beyond the tumor edge as defined from conventional MRI in low- and high-grade gliomas. We examined 12 patients with high-grade gliomas/glioblastomas and eight patients with low-grade gliomas and compared them to 10 patients with meningiomas, in which no tumor infiltration is expected. The tumor was defined as the enhancing area in glioblastomas and meningiomas and as the area of increased T2-signal in low-grade gliomas. FA and MD were measured in the center of the tumor and in the adjacent WM. The contralateral WM and internal capsule were used as an internal standard. Comparing the WM areas of increased T2-signal adjacent to meningiomas and glioblastomas, we saw a trend (without significance) towards a reduction of FA, but not of MD, in glioblastomas. We found no changes of FA and MD in the WM adjacent to low-grade gliomas (without T2-signal increase) compared to the WM of the contralateral hemisphere. In meningiomas and high-grade gliomas/glioblastomas, a narrow rim of significantly (P < 0.01) increased FA and decreased MD values around the enhancing tumor area was seen, whereas in low-grade gliomas, such a rim could not be defined. There was no contribution of FA or MD to grading of gliomas. In glioblastomas, a reduction of FA in the edematous area surrounding the tumor may indicate tumor cell infiltration, but a reliable differentiation between infiltration and vasogenic edema is not yet possible on the basis of DTI. The additional finding of a narrow rim of increased FA and decreased MD at the edge of glioblastomas (as well as in meningiomas) may be caused by com-pressed WM fibers and/or increased vascularity, but does not contribute to exclude peripheral cellular infiltration. 2004 Wiley-Liss, Inc.

Magnetic resonance diffusion tensor imaging of cervical spinal cord and lumbosacral enlargement in patients with cervical spondylotic myelopathy.

PubMed

Chen, Xueming; Kong, Chao; Feng, Shiqing; Guan, Hua; Yu, Zhenshan; Cui, Libin; Wang, Yanhui

2016-06-01

To identify the correlations of diffusion tensor imaging (DTI) indices between the cervical spinal cord and lumbosacral enlargement in healthy volunteers and patients with cervical spondylotic myelopathy (CSM). DTI was performed at the cervical spinal cord and lumbosacral enlargement in 10 CSM patients and 10 volunteers at 1.5T. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values of were measured and compared between CSM patients and volunteers. DTI indices of different cervical segments in volunteers were compared. DTI indices of the cervical spinal cord were correlated with those of the lumbosacral enlargement. In healthy subjects, DTI indices of different cervical cord sections showed no significant difference (ADC: F = 0.62; P = 0.65; FA: F = 1.228; P = 0.312); there was no correlation between the DTI indices of the cervical spinal cord and those of the lumbosacral enlargement (ADC: r = 0.442, P = 0.201; FA: r = -0.054, P = 0.881). In the CSM patients, the ADC value significantly increased, while the FA value significantly decreased in the cervical spinal cord (ADC: P = 0.002; FA: P < 0.001) and lumbosacral enlargement (ADC: P = 0.003; FA: P < 0.001) compared with the healthy group. Both DTI indices showed no correlation between the cervical spinal cord and those of the lumbosacral enlargement in the CSM group (ADC: r = -0.052, P = 0.887; FA: r = 0.129, P = 0.722). The ADC value of the cervical spinal cord and lumbosacral enlargement in CSM patients showed significant increase compared with healthy volunteers, while the FA value significantly decreased. Both DTI indices of the cervical spinal cord had no linear correlation with those of the lumbosacral enlargement. J. Magn. Reson. Imaging 2016;43:1484-1491. © 2015 Wiley Periodicals, Inc.

Fatty acid and stable isotope characteristics of sea ice and pelagic particulate organic matter in the Bering Sea: tools for estimating sea ice algal contribution to Arctic food web production.

PubMed

Wang, Shiway W; Budge, Suzanne M; Gradinger, Rolf R; Iken, Katrin; Wooller, Matthew J

2014-03-01

We determined fatty acid (FA) profiles and carbon stable isotopic composition of individual FAs (δ(13)CFA values) from sea ice particulate organic matter (i-POM) and pelagic POM (p-POM) in the Bering Sea during maximum ice extent, ice melt, and ice-free conditions in 2010. Based on FA biomarkers, differences in relative composition of diatoms, dinoflagellates, and bacteria were inferred for i-POM versus p-POM and for seasonal succession stages in p-POM. Proportions of diatom markers were higher in i-POM (16:4n-1, 6.6-8.7%; 20:5n-3, 19.6-25.9%) than in p-POM (16:4n-1, 1.2-4.0%; 20:5n-3, 5.5-14.0%). The dinoflagellate marker 22:6n-3/20:5n-3 was highest in p-POM. Bacterial FA concentration was higher in the bottom 1 cm of sea ice (14-245 μg L(-1)) than in the water column (0.6-1.7 μg L(-1)). Many i-POM δ(13)C(FA) values were higher (up to ~10‰) than those of p-POM, and i-POM δ(13)C(FA) values increased with day length. The higher i-POM δ(13)C(FA) values are most likely related to the reduced dissolved inorganic carbon (DIC) availability within the semi-closed sea ice brine channel system. Based on a modified Rayleigh equation, the fraction of sea ice DIC fixed in i-POM ranged from 12 to 73%, implying that carbon was not limiting for primary productivity in the sympagic habitat. These differences in FA composition and δ(13)C(FA) values between i-POM and p-POM will aid efforts to track the proportional contribution of sea ice algal carbon to higher trophic levels in the Bering Sea and likely other Arctic seas.

A DTI Study to Probe Tumor Microstructure And Its Connection With Hypoxia

PubMed Central

Majumdar, Shreyan; Triplett, William; Epel, Boris; Halpern, Howard

2015-01-01

Solid tumors have chaotic organization of blood vessels, disruptive nerve paths and muscle fibers that result in a hostile and heterogeneous microenvironment. These tumor regions are often hypoxic and resistant to radiation therapy. The knowledge of partial pressure of oxygen concentration (pO2), in conjunction with the information about tissue organization, can predict tissue health and may eventually be used in combination with intensity-modulated radiation therapy (IMRT) for targeted destruction of radiation-resistant areas, while sparing healthy tissues. Diffusion tensor imaging (DTI) based parameter fractional anisotropy (FA) can be used to assess organization of tissue microstructure, whereas the pO2 can be measured using electron paramagnetic resonance oxygen imaging (EPROI). This study is our first step to connect these two important physiological parameters. We calculated FA in fixed fibrosarcoma (FSa) grown in hind leg of nude mice (n = 6) using preclinical 9.4 T MRI. The FA in tumor region (0.34 ± 0.014) was found to be lower when compared to normal surrounding region (0.36 ± 0.013). We hypothesized that the change in FA is directly correlated with the change in oxygen concentration in tumor. We present preliminary in vivo results showing a positive correlation (R = 0.85, p = 0.017) between the FA and pO2 values acquired for MCa4 tumor (n = 1) using DTI and EPROI. PMID:25570064

A DTI study to probe tumor microstructure and its connection with hypoxia.

PubMed

Majumdar, Shreyan; Kotecha, Mrignayani; Triplett, William; Epel, Boris; Halpern, Howard

2014-01-01

Solid tumors have chaotic organization of blood vessels, disruptive nerve paths and muscle fibers that result in a hostile and heterogeneous microenvironment. These tumor regions are often hypoxic and resistant to radiation therapy. The knowledge of partial pressure of oxygen concentration (pO2), in conjunction with the information about tissue organization, can predict tissue health and may eventually be used in combination with intensity-modulated radiation therapy (IMRT) for targeted destruction of radiation-resistant areas, while sparing healthy tissues. Diffusion tensor imaging (DTI) based parameter fractional anisotropy (FA) can be used to assess organization of tissue microstructure, whereas the pO2 can be measured using electron paramagnetic resonance oxygen imaging (EPROI). This study is our first step to connect these two important physiological parameters. We calculated FA in fixed fibrosarcoma (FSa) grown in hind leg of nude mice (n = 6) using preclinical 9.4 T MRI. The FA in tumor region (0.34 ± 0.014) was found to be lower when compared to normal surrounding region (0.36 ± 0.013). We hypothesized that the change in FA is directly correlated with the change in oxygen concentration in tumor. We present preliminary in vivo results showing a positive correlation (R = 0.85, p = 0.017) between the FA and pO2 values acquired for MCa4 tumor (n = 1) using DTI and EPROI.

“The Relationship between Executive Functioning, Processing Speed and White Matter Integrity in Multiple Sclerosis”

PubMed Central

Genova, Helen M.; DeLuca, John; Chiaravalloti, Nancy; Wylie, Glenn

2014-01-01

The primary purpose of the current study was to examine the relationship between performance on executive tasks and white matter integrity, assessed by diffusion tensor imaging (DTI) in Multiple Sclerosis (MS). A second aim was to examine how processing speed affects the relationship between executive functioning and FA. This relationship was examined in two executive tasks that rely heavily on processing speed: the Color-Word Interference Test and Trail-Making Test (Delis-Kaplan Executive Function System). It was hypothesized that reduced fractional anisotropy (FA) is related to poor performance on executive tasks in MS, but that this relationship would be affected by the statistical correction of processing speed from the executive tasks. 15 healthy controls and 25 persons with MS participated. Regression analyses were used to examine the relationship between executive functioning and FA, both before and after processing speed was removed from the executive scores. Before processing speed was removed from the executive scores, reduced FA was associated with poor performance on Color-Word Interference Test and Trail-Making Test in a diffuse network including corpus callosum and superior longitudinal fasciculus. However, once processing speed was removed, the relationship between executive functions and FA was no longer significant on the Trail Making test, and significantly reduced and more localized on the Color-Word Interference Test. PMID:23777468

Positional Distribution of Fatty Acids in Triacylglycerols and Phospholipids from Fillets of Atlantic Salmon (Salmo Salar) Fed Vegetable and Fish Oil Blends.

PubMed

Ruiz-Lopez, Noemi; Stubhaug, Ingunn; Ipharraguerre, Ignacio; Rimbach, Gerald; Menoyo, David

2015-07-10

The nutritional and functional characteristics of dietary fat are related to the fatty acid (FA) composition and its positional distribution in the triacylglycerol (TAG) fraction. Atlantic salmon is an important source of healthy long chain omega 3 FA (particularly, eicosapentaenoic (EPA) and docoxahexaenoic (DHA) acids). However, the impact of lipid sources in salmon feeds on the regiospecificity of FA in the fish TAG remains to be explored. The present study determines the effect of feeding salmon with blends of palm, rapeseed, and fish oil, providing two different EPA + DHA concentrations (high: H-ED 10.3% and low: L-ED 4.6%) on the fillet lipid class composition and the positional distribution of FA in TAG and phospholipids. The regiospecific analysis of fillet TAG showed that around 50% of the EPA and around 80% of DHA was located in the sn-2 position. The positional distribution of FA in phosphatidylcholine (PC), showed that around 80% of the EPA and around 90% of DHA were located in the sn-2. Fish fed the vegetable-rich diets showed higher EPA in the sn-2 position in PC (77% vs. 83% in the H-ED and L-ED diets, respectively) but similar DHA concentrations. It is concluded that feeding salmon with different EPA + DHA concentrations does not affect their positional distribution in the fillet TAG.

Trait conscientiousness and the personality meta-trait stability are associated with regional white matter microstructure.

PubMed

Lewis, Gary J; Cox, Simon R; Booth, Tom; Muñoz Maniega, Susana; Royle, Natalie A; Valdés Hernández, Maria; Wardlaw, Joanna M; Bastin, Mark E; Deary, Ian J

2016-08-01

Establishing the neural bases of individual differences in personality has been an enduring topic of interest. However, while a growing literature has sought to characterize grey matter correlates of personality traits, little attention to date has been focused on regional white matter correlates of personality, especially for the personality traits agreeableness, conscientiousness and openness. To rectify this gap in knowledge we used a large sample (n > 550) of older adults who provided data on both personality (International Personality Item Pool) and white matter tract-specific fractional anisotropy (FA) from diffusion tensor MRI. Results indicated that conscientiousness was associated with greater FA in the left uncinate fasciculus (β = 0.17, P < 0.001). We also examined links between FA and the personality meta-trait 'stability', which is defined as the common variance underlying agreeableness, conscientiousness, and neuroticism/emotional stability. We observed an association between left uncinate fasciculus FA and stability (β = 0.27, P < 0.001), which fully accounted for the link between left uncinate fasciculus FA and conscientiousness. In sum, these results provide novel evidence for links between regional white matter microstructure and key traits of human personality, specifically conscientiousness and the meta-trait, stability. Future research is recommended to replicate and address the causal directions of these associations. © The Author (2016). Published by Oxford University Press.

A novel way to upgrade the coarse part of a high calcium fly ash for reuse into cement systems.

PubMed

Antiohos, S K; Tsimas, S

2007-01-01

Reject fly ash (rFA) represents a significant portion of the fly ashes produced from coal-fired power plants. Due to the high carbon content and large particle mean diameter, rFA is not utilized in the construction sector (for example, as supplementary cementing material) and is currently dumped into landfills, thus representing an additional environmental burden. Recently, the feasibility of using rFA in a relatively small number of applications, like solidification/stabilization of other wastes, has been investigated by different researchers. However, as the overall amount of fly ash utilized in such applications is still limited, there is a need to investigate other possibilities for rFA utilization starting from a deeper understanding of its properties. In the work presented herein, mechanical and hydration properties of cementitious materials prepared by blending the coarse fraction of a lignite high-calcium fly ash with ordinary cement were monitored and compared with the respective ones of a good quality fly ash-cement mixture. The results of this work reveal that a relatively cheap, bilateral classification-grinding method is able to promote the pozzolanic behavior of the rFAs, so that the overall performances of rFA containing cements are drastically improved. The evaluation of these results supports the belief that appropriate utilization of non-standardized materials may lead to new environmental-friendly products of superior quality.

Microstructural effects of Ramadan fasting on the brain: a diffusion tensor imaging study.

PubMed

Bakan, Ayse Ahsen; Yıldız, Seyma; Alkan, Alpay; Yetis, Huseyin; Kurtcan, Serpil; Ilhan, Mahmut Muzaffer

2015-01-01

We aimed to examine whether the brain displays any microstructural changes after a three-week Ramadan fasting period using diffusion tenson imaging. This study included a study and a control group of 25 volunteers each. In the study group, we examined and compared apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values of the participants during (phase 1) and after (phase 2) a period of fasting. The control group included individuals who did not fast. ADC and FA values obtained in phase 1 and phase 2 were compared between the study and control groups. In the study group, ADC values of hypothalamus and, to a lesser extent, of insula were lower in phase 1 compared with phase 2 and the control group. The FA values of amygdala, middle temporal cortex, thalamus and, to a lesser extent, of medial prefrontal cortex were lower in phase 1 compared with phase 2 and the control group. Phase 2 ADC and FA values of the study group were not significantly different compared with the control group at any brain location. A three-week Ramadan fasting period can cause microstructural changes in the brain, and diffusion tensor imaging enables the visualization of these changes. The identification of brain locations where changes occurred in ADC and FA values during fasting can be helpful in diagnostic imaging and understanding the pathophysiology of eating disorders.

Microstructural changes to the brain of mice after methamphetamine exposure as identified with diffusion tensor imaging.

PubMed

McKenna, Benjamin S; Brown, Gregory G; Archibald, Sarah; Scadeng, Miriam; Bussell, Robert; Kesby, James P; Markou, Athina; Soontornniyomkij, Virawudh; Achim, Cristian; Semenova, Svetlana

2016-03-30

Methamphetamine (METH) is an addictive psychostimulant inducing neurotoxicity. Human magnetic resonance imaging and diffusion tensor imaging (DTI) of METH-dependent participants find various structural abnormities. Animal studies demonstrate immunohistochemical changes in multiple cellular pathways after METH exposure. Here, we characterized the long-term effects of METH on brain microstructure in mice exposed to an escalating METH binge regimen using in vivo DTI, a methodology directly translatable across species. Results revealed four patterns of differential fractional anisotropy (FA) and mean diffusivity (MD) response when comparing METH-exposed (n=14) to saline-treated mice (n=13). Compared to the saline group, METH-exposed mice demonstrated: 1) decreased FA with no change in MD [corpus callosum (posterior forceps), internal capsule (left), thalamus (medial aspects), midbrain], 2) increased MD with no change in FA [posterior isocortical regions, caudate-putamen, hypothalamus, cerebral peduncle, internal capsule (right)], 3) increased FA with decreased MD [frontal isocortex, corpus callosum (genu)], and 4) increased FA with no change or increased MD [hippocampi, amygdala, lateral thalamus]. MD was negatively associated with calbindin-1 in hippocampi and positively with dopamine transporter in caudate-putamen. These findings highlight distributed and differential METH effects within the brain suggesting several distinct mechanisms. Such mechanisms likely change brain tissue differentially dependent upon neural location. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Fanconi anemia and homologous recombination gene variants are associated with functional DNA repair defects in vitro and poor outcome in patients with advanced head and neck squamous cell carcinoma

PubMed Central

Verhagen, Caroline V.M.; Vossen, David M.; Borgmann, Kerstin; Hageman, Floor; Grénman, Reidar; Verwijs-Janssen, Manon; Mout, Lisanne; Kluin, Roel J.C.; Nieuwland, Marja; Severson, Tesa M.; Velds, Arno; Kerkhoven, Ron; O’Connor, Mark J.; van der Heijden, Martijn; van Velthuysen, Marie-Louise; Verheij, Marcel; Wreesmann, Volkert B.; Wessels, Lodewyk F.A.; van den Brekel, Michiel W.M.; Vens, Conchita

2018-01-01

Mutations in Fanconi Anemia or Homologous Recombination (FA/HR) genes can cause DNA repair defects and could therefore impact cancer treatment response and patient outcome. Their functional impact and clinical relevance in head and neck squamous cell carcinoma (HNSCC) is unknown. We therefore questioned whether functional FA/HR defects occurred in HNSCC and whether they are associated with FA/HR variants. We assayed a panel of 29 patient-derived HNSCC cell lines and found that a considerable fraction is hypersensitive to the crosslinker Mitomycin C and PARP inhibitors, a functional measure of FA/HR defects. DNA sequencing showed that these hypersensitivities are associated with the presence of bi-allelic rare germline and somatic FA/HR gene variants. We next questioned whether such variants are associated with prognosis and treatment response in HNSCC patients. DNA sequencing of 77 advanced stage HNSCC tumors revealed a 19% incidence of such variants. Importantly, these variants were associated with a poor prognosis (p = 0.027; HR = 2.6, 1.1–6.0) but favorable response to high cumulative cisplatin dose. We show how an integrated in vitro functional repair and genomic analysis can improve the prognostic value of genetic biomarkers. We conclude that repair defects are marked and frequent in HNSCC and are associated with clinical outcome. PMID:29719599

Fanconi anemia and homologous recombination gene variants are associated with functional DNA repair defects in vitro and poor outcome in patients with advanced head and neck squamous cell carcinoma.

PubMed

Verhagen, Caroline V M; Vossen, David M; Borgmann, Kerstin; Hageman, Floor; Grénman, Reidar; Verwijs-Janssen, Manon; Mout, Lisanne; Kluin, Roel J C; Nieuwland, Marja; Severson, Tesa M; Velds, Arno; Kerkhoven, Ron; O'Connor, Mark J; van der Heijden, Martijn; van Velthuysen, Marie-Louise; Verheij, Marcel; Wreesmann, Volkert B; Wessels, Lodewyk F A; van den Brekel, Michiel W M; Vens, Conchita

2018-04-06

Mutations in Fanconi Anemia or Homologous Recombination (FA/HR) genes can cause DNA repair defects and could therefore impact cancer treatment response and patient outcome. Their functional impact and clinical relevance in head and neck squamous cell carcinoma (HNSCC) is unknown. We therefore questioned whether functional FA/HR defects occurred in HNSCC and whether they are associated with FA/HR variants. We assayed a panel of 29 patient-derived HNSCC cell lines and found that a considerable fraction is hypersensitive to the crosslinker Mitomycin C and PARP inhibitors, a functional measure of FA/HR defects. DNA sequencing showed that these hypersensitivities are associated with the presence of bi-allelic rare germline and somatic FA/HR gene variants. We next questioned whether such variants are associated with prognosis and treatment response in HNSCC patients. DNA sequencing of 77 advanced stage HNSCC tumors revealed a 19% incidence of such variants. Importantly, these variants were associated with a poor prognosis ( p = 0.027; HR = 2.6, 1.1-6.0) but favorable response to high cumulative cisplatin dose. We show how an integrated in vitro functional repair and genomic analysis can improve the prognostic value of genetic biomarkers. We conclude that repair defects are marked and frequent in HNSCC and are associated with clinical outcome.

Tract-based spatial statistics analysis of white matter changes in children with anisometropic amblyopia.

PubMed

Li, Qian; Zhai, Liying; Jiang, Qinying; Qin, Wen; Li, Qingji; Yin, Xiaohui; Guo, Mingxia

2015-06-15

Amblyopia is a neurological disorder of vision that follows abnormal binocular interaction or visual deprivation during early life. Previous studies have reported multiple functional or structural cortical alterations. Although white matter was also studied, it still cannot be clarified clearly which fasciculus was affected by amblyopia. In the present study, tract-based spatial statistics analysis was applied to diffusion tensor imaging (DTI) to investigate potential diffusion changes of neural tracts in anisometropic amblyopia. Fractional anisotropy (FA) value was calculated and compared between 20 amblyopic children and 18 healthy age-matched controls. In contrast to the controls, significant decreases in FA values were found in right optic radiation (OR), left inferior longitudinal fasciculus/inferior fronto-occipital fasciculus (ILF/IFO) and right superior longitudinal fasciculus (SLF) in the amblyopia. Furthermore, FA values of these identified tracts showed positive correlation with visual acuity. It can be inferred that abnormal visual input not only hinders OR from well developed, but also impairs fasciculi associated with dorsal and ventral visual pathways, which may be responsible for the amblyopic deficiency in object discrimination and stereopsis. Increased FA was detected in right posterior part of corpus callosum (CC) with a medium effect size, which may be due to compensation effect. DTI with subsequent measurement of FA is a useful tool for investigating neuronal tract involvement in amblyopia. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Numerical simulation model of hyperacute/acute stage white matter infarction.

PubMed

Sakai, Koji; Yamada, Kei; Oouchi, Hiroyuki; Nishimura, Tsunehiko

2008-01-01

Although previous studies have revealed the mechanisms of changes in diffusivity (apparent diffusion coefficient [ADC]) in acute brain infarction, changes in diffusion anisotropy (fractional anisotropy [FA]) in white matter have not been examined. We hypothesized that membrane permeability as well as axonal swelling play important roles, and we therefore constructed a simulation model using random walk simulation to replicate the diffusion of water molecules. We implemented a numerical diffusion simulation model of normal and infarcted human brains using C++ language. We constructed this 2-pool model using simple tubes aligned in a single direction. Random walk simulation diffused water. Axon diameters and membrane permeability were then altered in step-wise fashion. To estimate the effects of axonal swelling, axon diameters were changed from 6 to 10 microm. Membrane permeability was altered from 0% to 40%. Finally, both elements were combined to explain increasing FA in the hyperacute stage of white matter infarction. The simulation demonstrated that simple water shift into the intracellular space reduces ADC and increases FA, but not to the extent expected from actual human cases (ADC approximately 50%; FA approximately +20%). Similarly, membrane permeability alone was insufficient to explain this phenomenon. However, a combination of both factors successfully replicated changes in diffusivity indices. Both axonal swelling and reduced membrane permeability appear important in explaining changes in ADC and FA based on eigenvalues in hyperacute-stage white matter infarction.

White Matter Integrity and Pictorial Reasoning in High-Functioning Children with Autism

PubMed Central

Sahyoun, Chérif P.; Belliveau, John W.; Mody, Maria

2010-01-01

The current study investigated the neurobiological role of white matter in visuospatial versus linguistic processing abilities in autism using diffusion tensor imaging. We examined differences in white matter integrity between high-functioning children with autism (HFA) and typically developing controls (CTRL), in relation to the groups’ response times (RT) on a pictorial reasoning task under three conditions: visuospatial, V, semantic, S, and V+S, a hybrid condition allowing language use to facilitate visuospatial transformations. Diffusion-weighted images were collected from HFA and CTRL participants, matched on age and IQ, and significance maps were computed for group differences in fractional anisotropy (FA) and in RT-FA association for each condition. Typically developing children showed increased FA within frontal white matter and the superior longitudinal fasciculus (SLF). HFA showed increased FA within peripheral white matter, including the ventral temporal lobe. Additionally, RT-FA relationships in the semantic condition (S) implicated white matter near the STG and in the SLF within the temporal and frontal lobes to a greater extent in CTRL. Performance in visuospatial reasoning (V, V+S), in comparison, was related to peripheral parietal and superior precentral white matter in HFA, but to the SLF, callosal, and frontal white matter in CTRL. Our results appear to support a preferential use of linguistically-mediated pathways in reasoning by typically-developing children, whereas autistic cognition may rely more on visuospatial processing networks. PMID:20542370

The Pattern of Fatty Acids Displaced by EPA and DHA Following 12 Months Supplementation Varies between Blood Cell and Plasma Fractions.

PubMed

Walker, Celia G; West, Annette L; Browning, Lucy M; Madden, Jackie; Gambell, Joanna M; Jebb, Susan A; Calder, Philip C

2015-08-03

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are increased in plasma lipids and blood cell membranes in response to supplementation. Whilst arachidonic acid (AA) is correspondingly decreased, the effect on other fatty acids (FA) is less well described and there may be site-specific differences. In response to 12 months EPA + DHA supplementation in doses equivalent to 0-4 portions of oily fish/week (1 portion: 3.27 g EPA+DHA) multinomial regression analysis was used to identify important FA changes for plasma phosphatidylcholine (PC), cholesteryl ester (CE) and triglyceride (TAG) and for blood mononuclear cells (MNC), red blood cells (RBC) and platelets (PLAT). Dose-dependent increases in EPA + DHA were matched by decreases in several n-6 polyunsaturated fatty acids (PUFA) in PC, CE, RBC and PLAT, but were predominantly compensated for by oleic acid in TAG. Changes were observed for all FA classes in MNC. Consequently the n-6:n-3 PUFA ratio was reduced in a dose-dependent manner in all pools after 12 months (37%-64% of placebo in the four portions group). We conclude that the profile of the FA decreased in exchange for the increase in EPA + DHA following supplementation differs by FA pool with implications for understanding the impact of n-3 PUFA on blood lipid and blood cell biology.

Differentiation between phyllodes tumours and fibroadenomas using intravoxel incoherent motion magnetic resonance imaging: comparison with conventional diffusion-weighted imaging.

PubMed

Kawashima, Hiroko; Miyati, Tosiaki; Ohno, Naoki; Ohno, Masako; Inokuchi, Masafumi; Ikeda, Hiroko; Gabata, Toshifumi

2018-04-01

To investigate whether the parameters derived from intravoxel incoherent motion (IVIM) MRI could differentiate phyllodes tumours (PTs) from fibroadenomas (FAs) by comparing the apparent diffusion coefficient (ADC) values. This retrospective study included 7 FAs, 10 benign PTs (BPTs), 4 borderline PTs, and one malignant PT. Biexponential analyses of IVIM were performed using a 3 T MRI scanner. Quantitative IVIM parameters [pure diffusion coefficient (D), perfusion-related diffusion coefficient (D*), and fraction (f)] were calculated. The ADC was also calculated using monoexponential fitting. The D and ADC values showed an increasing tendency in the order of FA, BPT, and borderline or malignant PT (BMPT). No significant difference was found in the D value among the three groups. The ADC value of the BMPT group was significantly higher than that of the FA group (p = 0.048). The D* value showed an increasing tendency in the order of BMPT, BPT, and FA, and the D* value of the BMPT group was significantly lower than that of the FA group (p = 0.048). The D* derived from IVIM and the ADC were helpful for differentiating between FA and BMPT. Advances in knowledge: IVIM MRI examination showed that the perfusion-related diffusion coefficient is lower in borderline and malignant PTs than in FAs and the opposite is true for the ADC.

Microstructural effects of Ramadan fasting on the brain: a diffusion tensor imaging study

PubMed Central

Bakan, Ayse Ahsen; Yıldız, Seyma; Alkan, Alpay; Yetis, Huseyin; Kurtcan, Serpil; Ilhan, Mahmut Muzaffer

2015-01-01

PURPOSE We aimed to examine whether the brain displays any microstructural changes after a three-week Ramadan fasting period using diffusion tenson imaging. METHODS This study included a study and a control group of 25 volunteers each. In the study group, we examined and compared apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values of the participants during (phase 1) and after (phase 2) a period of fasting. The control group included individuals who did not fast. ADC and FA values obtained in phase 1 and phase 2 were compared between the study and control groups. RESULTS In the study group, ADC values of hypothalamus and, to a lesser extent, of insula were lower in phase 1 compared with phase 2 and the control group. The FA values of amygdala, middle temporal cortex, thalamus and, to a lesser extent, of medial prefrontal cortex were lower in phase 1 compared with phase 2 and the control group. Phase 2 ADC and FA values of the study group were not significantly different compared with the control group at any brain location. CONCLUSION A three-week Ramadan fasting period can cause microstructural changes in the brain, and diffusion tensor imaging enables the visualization of these changes. The identification of brain locations where changes occurred in ADC and FA values during fasting can be helpful in diagnostic imaging and understanding the pathophysiology of eating disorders. PMID:25835077

The Pattern of Fatty Acids Displaced by EPA and DHA Following 12 Months Supplementation Varies between Blood Cell and Plasma Fractions

PubMed Central

Walker, Celia G.; West, Annette L.; Browning, Lucy M.; Madden, Jackie; Gambell, Joanna M.; Jebb, Susan A.; Calder, Philip C.

2015-01-01

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are increased in plasma lipids and blood cell membranes in response to supplementation. Whilst arachidonic acid (AA) is correspondingly decreased, the effect on other fatty acids (FA) is less well described and there may be site-specific differences. In response to 12 months EPA + DHA supplementation in doses equivalent to 0–4 portions of oily fish/week (1 portion: 3.27 g EPA+DHA) multinomial regression analysis was used to identify important FA changes for plasma phosphatidylcholine (PC), cholesteryl ester (CE) and triglyceride (TAG) and for blood mononuclear cells (MNC), red blood cells (RBC) and platelets (PLAT). Dose-dependent increases in EPA + DHA were matched by decreases in several n-6 polyunsaturated fatty acids (PUFA) in PC, CE, RBC and PLAT, but were predominantly compensated for by oleic acid in TAG. Changes were observed for all FA classes in MNC. Consequently the n-6:n-3 PUFA ratio was reduced in a dose-dependent manner in all pools after 12 months (37%–64% of placebo in the four portions group). We conclude that the profile of the FA decreased in exchange for the increase in EPA + DHA following supplementation differs by FA pool with implications for understanding the impact of n-3 PUFA on blood lipid and blood cell biology. PMID:26247960

Diffusion Tensor Tractography of the Cerebellar Peduncles in Prematurely Born 7-Year-Old Children.

PubMed

Shany, Eilon; Inder, Terrie E; Goshen, Sharon; Lee, Iris; Neil, Jeffrey J; Smyser, Christopher D; Doyle, Lex W; Anderson, Peter J; Shimony, Joshua S

2017-04-01

The objective of this study was to correlate neurodevelopmental outcome of preterm-born children and their perinatal clinical and imaging characteristics with diffusion magnetic resonance imaging (MRI) measures of the three cerebellar peduncles at age 7. Included in this prospective longitudinal study were 140 preterm-born children (<30 weeks gestation) who underwent neurodevelopmental assessment (IQ, motor, language, working memory) and diffusion-weighted imaging (DWI) at age 7 years. White matter tracts in the superior, middle, and inferior cerebellar peduncles were delineated using regions of interest drawn on T2-weighted images and fractional anisotropy (FA) maps. Diffusion measures (mean diffusivity (MD) and FA) and tract volumes were calculated. Linear regression was used to assess relationships with outcome. The severity of white matter injury in the neonatal period was associated with lower FA in the right superior cerebellar peduncle (SCP) and lower tract volumes of both SCPs and middle cerebellar peduncles (MCPs). In the MCP, higher IQ was associated with lower MD in the whole group and higher FA in right-handed children. In the SCP, lower motor scores were associated with higher MD and higher language scores were associated with higher FA. These associations remained significant in multivariable models. This study adds to the body of literature detailing the importance of cerebellar involvement in cognitive function related to reciprocal connections with supratentorial structures.

Serial Diffusion Tensor Imaging of the Optic Radiations after Acute Optic Neuritis.

PubMed

Kolbe, Scott C; van der Walt, Anneke; Butzkueven, Helmut; Klistorner, Alexander; Egan, Gary F; Kilpatrick, Trevor J

2016-01-01

Previous studies have reported diffusion tensor imaging (DTI) changes within the optic radiations of patients after optic neuritis (ON). We aimed to study optic radiation DTI changes over 12 months following acute ON and to study correlations between DTI parameters and damage to the optic nerve and primary visual cortex (V1). We measured DTI parameters [fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (MD)] from the optic radiations of 38 acute ON patients at presentation and 6 and 12 months after acute ON. In addition, we measured retinal nerve fibre layer thickness, visual evoked potential amplitude, optic radiation lesion load, and V1 thickness. At baseline, FA was reduced and RD and MD were increased compared to control. Over 12 months, FA reduced in patients at an average rate of -2.6% per annum (control = -0.51%; p = 0.006). Change in FA, RD, and MD correlated with V1 thinning over 12 months (FA: R = 0.450, p = 0.006; RD: R = -0.428, p = 0.009; MD: R = -0.365, p = 0.029). In patients with no optic radiation lesions, AD significantly correlated with RNFL thinning at 12 months (R = 0.489, p = 0.039). In conclusion, DTI can detect optic radiation changes over 12 months following acute ON that correlate with optic nerve and V1 damage.

Serial Diffusion Tensor Imaging of the Optic Radiations after Acute Optic Neuritis

PubMed Central

van der Walt, Anneke; Butzkueven, Helmut; Klistorner, Alexander; Egan, Gary F.; Kilpatrick, Trevor J.

2016-01-01

Previous studies have reported diffusion tensor imaging (DTI) changes within the optic radiations of patients after optic neuritis (ON). We aimed to study optic radiation DTI changes over 12 months following acute ON and to study correlations between DTI parameters and damage to the optic nerve and primary visual cortex (V1). We measured DTI parameters [fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (MD)] from the optic radiations of 38 acute ON patients at presentation and 6 and 12 months after acute ON. In addition, we measured retinal nerve fibre layer thickness, visual evoked potential amplitude, optic radiation lesion load, and V1 thickness. At baseline, FA was reduced and RD and MD were increased compared to control. Over 12 months, FA reduced in patients at an average rate of −2.6% per annum (control = −0.51%; p = 0.006). Change in FA, RD, and MD correlated with V1 thinning over 12 months (FA: R = 0.450, p = 0.006; RD: R = −0.428, p = 0.009; MD: R = −0.365, p = 0.029). In patients with no optic radiation lesions, AD significantly correlated with RNFL thinning at 12 months (R = 0.489, p = 0.039). In conclusion, DTI can detect optic radiation changes over 12 months following acute ON that correlate with optic nerve and V1 damage. PMID:27555964

Positional Distribution of Fatty Acids in Triacylglycerols and Phospholipids from Fillets of Atlantic Salmon (Salmo Salar) Fed Vegetable and Fish Oil Blends

PubMed Central

Ruiz-Lopez, Noemi; Stubhaug, Ingunn; Ipharraguerre, Ignacio; Rimbach, Gerald; Menoyo, David

2015-01-01

The nutritional and functional characteristics of dietary fat are related to the fatty acid (FA) composition and its positional distribution in the triacylglycerol (TAG) fraction. Atlantic salmon is an important source of healthy long chain omega 3 FA (particularly, eicosapentaenoic (EPA) and docoxahexaenoic (DHA) acids). However, the impact of lipid sources in salmon feeds on the regiospecificity of FA in the fish TAG remains to be explored. The present study determines the effect of feeding salmon with blends of palm, rapeseed, and fish oil, providing two different EPA + DHA concentrations (high: H-ED 10.3% and low: L-ED 4.6%) on the fillet lipid class composition and the positional distribution of FA in TAG and phospholipids. The regiospecific analysis of fillet TAG showed that around 50% of the EPA and around 80% of DHA was located in the sn-2 position. The positional distribution of FA in phosphatidylcholine (PC), showed that around 80% of the EPA and around 90% of DHA were located in the sn-2. Fish fed the vegetable-rich diets showed higher EPA in the sn-2 position in PC (77% vs. 83% in the H-ED and L-ED diets, respectively) but similar DHA concentrations. It is concluded that feeding salmon with different EPA + DHA concentrations does not affect their positional distribution in the fillet TAG. PMID:26184234

The role of diffusion tensor imaging and fractional anisotropy in the evaluation of patients with idiopathic normal pressure hydrocephalus: a literature review.

PubMed

Siasios, Ioannis; Kapsalaki, Eftychia Z; Fountas, Kostas N; Fotiadou, Aggeliki; Dorsch, Alexander; Vakharia, Kunal; Pollina, John; Dimopoulos, Vassilios

2016-09-01

OBJECTIVE Diffusion tensor imaging (DTI) for the assessment of fractional anisotropy (FA) and involving measurements of mean diffusivity (MD) and apparent diffusion coefficient (ADC) represents a novel, MRI-based, noninvasive technique that may delineate microstructural changes in cerebral white matter (WM). For example, DTI may be used for the diagnosis and differentiation of idiopathic normal pressure hydrocephalus (iNPH) from other neurodegenerative diseases with similar imaging findings and clinical symptoms and signs. The goal of the current study was to identify and analyze recently published series on the use of DTI as a diagnostic tool. Moreover, the authors also explored the utility of DTI in identifying patients with iNPH who could be managed by surgical intervention. METHODS The authors performed a literature search of the PubMed database by using any possible combinations of the following terms: "Alzheimer's disease," "brain," "cerebrospinal fluid," "CSF," "diffusion tensor imaging," "DTI," "hydrocephalus," "idiopathic," "magnetic resonance imaging," "normal pressure," "Parkinson's disease," and "shunting." Moreover, all reference lists from the retrieved articles were reviewed to identify any additional pertinent articles. RESULTS The literature search retrieved 19 studies in which DTI was used for the identification and differentiation of iNPH from other neurodegenerative diseases. The DTI protocols involved different approaches, such as region of interest (ROI) methods, tract-based spatial statistics, voxel-based analysis, and delta-ADC analysis. The most studied anatomical regions were the periventricular WM areas, such as the internal capsule (IC), the corticospinal tract (CST), and the corpus callosum (CC). Patients with iNPH had significantly higher MD in the periventricular WM areas of the CST and the CC than had healthy controls. In addition, FA and ADCs were significantly higher in the CST of iNPH patients than in any other patients with other neurodegenerative diseases. Gait abnormalities of iNPH patients were statistically significantly and negatively correlated with FA in the CST and the minor forceps. Fractional anisotropy had a sensitivity of 94% and a specificity of 80% for diagnosing iNPH. Furthermore, FA and MD values in the CST, the IC, the anterior thalamic region, the fornix, and the hippocampus regions could help differentiate iNPH from Alzheimer or Parkinson disease. Interestingly, CSF drainage or ventriculoperitoneal shunting significantly modified FA and ADCs in iNPH patients whose condition clinically responded to these maneuvers. CONCLUSIONS Measurements of FA and MD significantly contribute to the detection of axonal loss and gliosis in the periventricular WM areas in patients with iNPH. Diffusion tensor imaging may also represent a valuable noninvasive method for differentiating iNPH from other neurodegenerative diseases. Moreover, DTI can detect dynamic changes in the WM tracts after lumbar drainage or shunting procedures and could help identify iNPH patients who may benefit from surgical intervention.

Pharmacokinetic evidence for improved ophthalmic drug delivery by reduction of instilled volume.

PubMed

Patton, T F

1977-07-01

The bioavailability of topically applied pilocarpine nitrate was studied as a function of instilled volume. As the instilled volume decreased, the fraction of dose absorbed increased. The relationship between fraction absorbed and instilled volume was not direct, but appropriate adjustment of instilled volume and concentration should permit substantial dosage reductions without sacrifice of drug concentration in the eye. The implications of these findings from both a therapeutic and toxicity standpoint are discussed.

Anisotropic diffusion of metabolites in peripheral nerve using diffusion weighted magnetic resonance spectroscopy at ultra-high field

NASA Astrophysics Data System (ADS)

Ellegood, Jacob; McKay, Ryan T.; Hanstock, Chris C.; Beaulieu, Christian

2007-01-01

Although the diffusivity and anisotropy of water has been investigated thoroughly in ordered axonal systems (i.e., nervous tissue), there have been very few studies on the directional dependence of diffusion of metabolites. In this study, the mean apparent diffusion coefficient (Trace/3 ADC) and fractional anisotropy (FA) values of the intracellular metabolites N-acetyl aspartate (NAA), creatine and phosphocreatine (tCr), choline (Cho), taurine (Tau), and glutamate and glutamine (Glx) were measured parallel and perpendicular to the length of excised frog sciatic nerve using a water suppressed, diffusion-weighted, spin-echo pulse sequence at 18.8 T. The degree of anisotropy (FA) of NAA (0.41 ± 0.09) was determined to be less than tCr (0.59 ± 0.07) and Cho (0.61 ± 0.11), which is consistent with previously reported human studies of white matter. In contrast, Glx diffusion was found to be almost isotropic with an FA value of 0.20 ± 0.06. The differences of FA between the metabolites is most likely due to their differing micro-environments and could be beneficial as an indicator of compartment specific changes with disease, information not readily available with water diffusion.

In vivo assessment of peripheral nerve regeneration by diffusion tensor imaging.

PubMed

Morisaki, Shinsuke; Kawai, Yuko; Umeda, Masahiro; Nishi, Mayumi; Oda, Ryo; Fujiwara, Hiroyoshi; Yamada, Kei; Higuchi, Toshihiro; Tanaka, Chuzo; Kawata, Mitsuhiro; Kubo, Toshikazu

2011-03-01

To evaluate the sensitivity of diffusion tensor imaging (DTI) in assessing peripheral nerve regeneration in vivo. We assessed the changes in the DTI parameters and histological analyses after nerve injury to examine degeneration and regeneration in the rat sciatic nerves. For magnetic resonance imaging (MRI), 16 rats were randomly divided into two groups: group P (permanently crushed; n = 7) and group T (temporally crushed; n = 9). Serial MRI of the right leg was performed before the operation, and then performed at the timepoints of 1, 2, 3, and 4 weeks after the crush injury. The changes in fractional anisotropy (FA), axial diffusivity (λ(∥)), and radial diffusivity (λ(⟂)) were quantified. For histological analyses, the number of axons and the myelinated axon areas were quantified. Decreased FA and increased λ(⟂) were observed in the degenerative phase, and increased FA and decreased λ(⟂) were observed in the regenerative phase. The changes in FA and λ(⟂) were strongly correlated with histological changes, including axonal and myelin regeneration. DTI parameters, especially λ(⟂) , can be good indicators for peripheral nerve regeneration and can be applied as noninvasive diagnostic tools for a variety of neurological diseases. Copyright © 2011 Wiley-Liss, Inc.

Fatty acid composition of polar and neutral meat lipids of goats browsing in native pasture of Brazilian Semiarid.

PubMed

Fonteles, Natália L O; Alves, Susana P; Madruga, Marta Suely; Queiroga, Rita R E; Andrade, Albericio P; Silva, Divan S; Leal, Amanda P; Bessa, Rui J B; Medeiros, Ariosvaldo N

2018-05-01

Thirty six male goats grazing Caatinga native pasture were randomly assigned to 4 concentrate supplementation levels (0, 5, 10 and 15g/kg of body weight) and slaughtered after 120days. Longissimus muscle meat lipids were extracted and fractionated into neutral (NL) and polar (PL) lipids. Supplementation of grazing goats increased linearly (P<0.05) intramuscular fat (1 to 1.5% of meat) and NL (0.3 to 1% of meat) but decreased linearly (P=0.044) the PL (0.66 to 0.50% of meat). On NL, supplementation increased linearly (P=0.047) the proportion of c9-18:1 (31 to 40% of FA) with supplementation. On PL, supplementation reduced linearly (P<0.03) the dimethyl acetals, 18:3n-3 and most of long chain polyunsaturated FA (PUFA) proportions but increased linearly (P<0.001) the c9-18:1. Considering the total meat FA, supplementation led to an increase of the saturated and monounsaturated FA contents and a decrease of the long chain n-6 and n-3 PUFA contents. Copyright © 2018 Elsevier Ltd. All rights reserved.

Structural white matter changes in adolescents and young adults with maple syrup urine disease.

PubMed

Klee, D; Thimm, E; Wittsack, H J; Schubert, D; Primke, R; Pentang, G; Schaper, J; Mödder, U; Antoch, A; Wendel, U; Cohnen, M

2013-11-01

To get insight into the nature of magnetic resonance (MR) white matter abnormalities of patients with classic maple syrup urine disease (MSUD) under diet control. Ten patients with classic MSUD and one with a severe MSUD variant (mean age 21.5 ± 5.1 years) on diet and 11 age and sex-matched healthy subjects were enrolled. Apart from standard MR sequences, diffusion weighted images (DWI), diffusion tensor images (DTI), and magnetization transfer images (MT) were obtained and comparatively analyzed for apparent diffusion coefficient (ADC), tensor fractional anisotropy (FA) and MT maps in 11 regions of interest (ROI) within the white matter. In MSUD patients DWI, DTI and FA showed distinct signal changes in the cerebral hemispheres, the dorsal limb of internal capsule, the brain stem and the central cerebellum. Signal intensity was increased in DWI with a reduced ADC and decreased values for FA. MT did not reveal differences between patients and control subjects. Signal abnormalities in the white matter of adolescents and young adults under diet control may be interpreted as consequence of structural alterations like dysmyelination. The reduced ADC and FA in the white matter with preserved MT indicate a reduction in fiber tracks.

Disorganization of white matter architecture in major depressive disorder: a meta-analysis of diffusion tensor imaging with tract-based spatial statistics.

PubMed

Chen, Guangxiang; Hu, Xinyu; Li, Lei; Huang, Xiaoqi; Lui, Su; Kuang, Weihong; Ai, Hua; Bi, Feng; Gu, Zhongwei; Gong, Qiyong

2016-02-24

White matter (WM) abnormalities have long been suspected in major depressive disorder (MDD). Tract-based spatial statistics (TBSS) studies have detected abnormalities in fractional anisotropy (FA) in MDD, but the available evidence has been inconsistent. We performed a quantitative meta-analysis of TBSS studies contrasting MDD patients with healthy control subjects (HCS). A total of 17 studies with 18 datasets that included 641 MDD patients and 581 HCS were identified. Anisotropic effect size-signed differential mapping (AES-SDM) meta-analysis was performed to assess FA alterations in MDD patients compared to HCS. FA reductions were identified in the genu of the corpus callosum (CC) extending to the body of the CC and left anterior limb of the internal capsule (ALIC) in MDD patients relative to HCS. Descriptive analysis of quartiles, sensitivity analysis and subgroup analysis further confirmed these findings. Meta-regression analysis revealed that individuals with more severe MDD were significantly more likely to have FA reductions in the genu of the CC. This study provides a thorough profile of WM abnormalities in MDD and evidence that interhemispheric connections and frontal-striatal-thalamic pathways are the most convergent circuits affected in MDD.

Eddy current compensated double diffusion encoded (DDE) MRI.

PubMed

Mueller, Lars; Wetscherek, Andreas; Kuder, Tristan Anselm; Laun, Frederik Bernd

2017-01-01

Eddy currents might lead to image distortions in diffusion-weighted echo planar imaging. A method is proposed to reduce their effects on double diffusion encoding (DDE) MRI experiments and the thereby derived microscopic fractional anisotropy (μFA). The twice-refocused spin echo scheme was adapted for DDE measurements. To assess the effect of individual diffusion encodings on the image distortions, measurements of a grid of plastic rods in water were performed. The effect of eddy current compensation on μFA measurements was evaluated in the brains of six healthy volunteers. The use of an eddy current compensation reduced the signal variation. As expected, the distortions caused by the second encoding were larger than those of the first encoding, entailing a stronger need to compensate for them. For an optimal result, however, both encodings had to be compensated. The artifact reduction strongly improved the measurement of the μFA in ventricles and gray matter by reducing the overestimation. An effect of the compensation on absolute μFA values in white matter was not observed. It is advisable to compensate both encodings in DDE measurements for eddy currents. Magn Reson Med 77:328-335, 2017. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Sex-specific association between infant diet and white matter integrity in 8-y-old children.

PubMed

Ou, Xiawei; Andres, Aline; Cleves, Mario A; Pivik, R T; Snow, Jeffrey H; Ding, Zhaohua; Badger, Thomas M

2014-12-01

The American Academy of Pediatrics recommends breastfeeding, which is well known to promote cognitive and behavioral development. The evidence for why this occurs is not well understood. Fifty-six 7.5- to 8.5-y-old healthy children were breastfed (BF; n = 22, 10 males) or formula-fed (FF; n = 34, 16 males) as infants. All children were administered: the Reynolds Intellectual Assessment Scale (RIAS); the Clinical Evaluation of Language Fundamentals (CELF-4) tests; and magnetic resonance imaging of the brain. Diffusion tensor imaging (DTI) measured fractional anisotropy (FA) values were correlated with RIAS and CELF-4 scores. DTI tract-based spatial statistics (TBSS) analyses showed multiple white matter regions in the left hemisphere with significantly higher FA (P < 0.05, corrected) values in BF than FF males, but no significant group differences in females. Males who were exclusively BF for at least 1 y appeared to have the greatest differences in FA. Mean FA values positively correlated with composite scores of RIAS (P = 0.03) and CELF-4 (P = 0.02). Breastfeeding during infancy was associated with better white matter development at 8 y of age in boys. A similar association was not observed in girls.

Impaired Frontal-Limbic White Matter Maturation in Children at Risk for Major Depression.

PubMed

Hung, Yuwen; Saygin, Zeynep M; Biederman, Joseph; Hirshfeld-Becker, Dina; Uchida, Mai; Doehrmann, Oliver; Han, Michelle; Chai, Xiaoqian J; Kenworthy, Tara; Yarmak, Pavel; Gaillard, Schuyler L; Whitfield-Gabrieli, Susan; Gabrieli, John D E

2017-09-01

Depression is among the most common neuropsychiatric disorders. It remains unclear whether brain abnormalities associated with depression reflect the pathological state of the disease or neurobiological traits predisposing individuals to depression. Parental history of depression is a risk factor that more than triples the risk of depression. We compared white matter (WM) microstructure cross-sectionally in 40 children ages 8-14 with versus without parental history of depression (At-Risk vs. Control). There were significant differences in age-related changes of fractional anisotropy (FA) between the groups, localized in the anterior fronto-limbic WM pathways, including the anterior cingulum and the genu of the corpus callosum. Control children exhibited typical increasing FA with age, whereas At-Risk children exhibited atypical decreasing FA with age in these fronto-limbic regions. Furthermore, dorsal cingulate FA significantly correlated with depressive symptoms for At-Risk children. The results suggest maturational WM microstructure differences in mood-regulatory neurocircuitry that may contribute to neurodevelopmental risk for depression. The study provides new insights into neurodevelopmental susceptibility to depression and related disabilities that may promote early preventive intervention approaches. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Queensland Pastures

Atmospheric Science Data Center

2013-04-16

... or space is absorbed by either the vegetation or the soil. The fraction of PAR radiation absorbed by green vegetation, known as ... NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Science Mission Directorate, Washington, D.C. The Terra spacecraft is managed ...

Evaluation of normal appearing spinal cord by diffusion tensor imaging, fiber tracking, fractional anisotropy, and apparent diffusion coefficient measurement in 13 dogs

PubMed Central

2013-01-01

Background Functional magnetic resonance (fMR) imaging offers plenty of new opportunities in the diagnosis of central nervous system diseases. Diffusion tensor imaging (DTI) is a technique sensitive to the random motion of water providing information about tissue architecture. We applied DTI to normal appearing spinal cords of 13 dogs of different breeds and body weights in a 3.0 T magnetic resonance (MR) scanner. The aim was to study fiber tracking (FT) patterns by tractography and the variations of the fractional anisotropy (FA) and the apparent diffusion coefficient (ADC) observed in the spinal cords of dogs with different sizes and at different locations (cervical and thoracolumbar). For that reason we added a DTI sequence to the standard clinical MR protocol. The values of FA and ADC were calculated by means of three regions of interest defined on the cervical or the thoracolumbar spinal cord (ROI 1, 2, and 3). Results The shape of the spinal cord fiber tracts was well illustrated following tractography and the exiting nerve roots could be differentiated from the spinal cord fiber tracts. Routine MR scanning times were extended for 8 to 12 min, depending on the size of the field of view (FOV), the slice thickness, and the size of the interslice gaps. In small breed dogs (< 15 kg body weight) the fibers could be tracked over a length of approximately 10 vertebral bodies with scanning times of about 8 min, whereas in large breed dogs (> 25 kg body weight) the traceable fiber length was about 5 vertebral bodies which took 10 to 12 min scanning time. FA and ADC values showed mean values of 0.447 (FA), and 0.560 × 10-3 mm2/s (ADC), respectively without any differences detected with regard to different dog sizes and spinal cord 45 segments examined. Conclusion FT is suitable for the graphical depiction of the canine spinal cord and the exiting nerve roots. The FA and ADC values offer an objective measure for evaluation of the spinal cord fiber integrity in dogs. PMID:23618404

Induction of plasminogen activator inhibitor type-1 (PAI-1) by hypoxia and irradiation in human head and neck carcinoma cell lines.

PubMed

Schilling, Daniela; Bayer, Christine; Geurts-Moespot, Anneke; Sweep, Fred C G J; Pruschy, Martin; Mengele, Karin; Sprague, Lisa D; Molls, Michael

2007-07-30

Squamous cell carcinoma of the head and neck (SCCHN) often contain highly radioresistant hypoxic regions, nonetheless, radiotherapy is a common treatment modality for these tumours. Reoxygenation during fractionated radiotherapy is desired to render these hypoxic tumour regions more radiosensitive. Hypoxia additionally leads to up-regulation of PAI-1, a protein involved in tumour progression and an established prognostic marker for poor outcome. However, the impact of reoxygenation and radiation on PAI-1 levels is not yet clear. Therefore, we investigated the kinetics of PAI-1 expression and secretion after hypoxia and reoxygenation, and determined the influence of ionizing radiation on PAI-1 levels in the two human SCCHN cell lines, BHY and FaDu. HIF-1alpha immunoblot was used to visualize the degree of hypoxia in the two cell lines. Cellular PAI-1 expression was investigated by immunofluorescence microscopy. ELISA was used to quantify relative changes in PAI-1 expression (cell lysates) and secretion (cell culture supernatants) in response to various lengths (2-4 h) of hypoxic exposure (< 0.66% O2), reoxygenation (24 h, 20% O2), and radiation (0, 2, 5 and 10 Gy). HIF-1alpha expression was induced between 2 and 24 h of hypoxic exposure. Intracellular PAI-1 expression was significantly increased in BHY and FaDu cells as early as 4 h after hypoxic exposure. A significant induction in secreted PAI-1 was seen after 12 to 24 h (BHY) and 8 to 24 h (FaDu) hypoxia, as compared to the normoxic control. A 24 h reoxygenation period caused significantly less PAI-1 secretion than a 24 h hypoxia period in FaDu cells. Irradiation led to an up-regulation of PAI-1 expression and secretion in both, BHY and FaDu cells. Our data suggest that both, short-term (approximately 4-8 h) and long-term (approximately 20-24 h) hypoxic exposure could increase PAI-1 levels in SCCHN in vivo. Importantly, radiation itself could lead to PAI-1 up-regulation in head and neck tumours, whereas reoxygenation of hypoxic tumour cells during fractionated radiotherapy could counteract the increased PAI-1 levels.

White Matter Integrity Dissociates Verbal Memory and Auditory Attention Span in Emerging Adults with Congenital Heart Disease.

PubMed

Brewster, Ryan C; King, Tricia Z; Burns, Thomas G; Drossner, David M; Mahle, William T

2015-01-01

White matter disruptions have been identified in individuals with congenital heart disease (CHD). However, no specific theory-driven relationships between microstructural white matter disruptions and cognition have been established in CHD. We conducted a two-part study. First, we identified significant differences in fractional anisotropy (FA) of emerging adults with CHD using Tract-Based Spatial Statistics (TBSS). TBSS analyses between 22 participants with CHD and 18 demographically similar controls identified five regions of normal appearing white matter with significantly lower FA in CHD, and two higher. Next, two regions of lower FA in CHD were selected to examine theory-driven differential relationships with cognition: voxels along the left uncinate fasciculus (UF; a tract theorized to contribute to verbal memory) and voxels along the right middle cerebellar peduncle (MCP; a tract previously linked to attention). In CHD, a significant positive correlation between UF FA and memory was found, r(20)=.42, p=.049 (uncorrected). There was no correlation between UF and auditory attention span. A positive correlation between MCP FA and auditory attention span was found, r(20)=.47, p=.027 (uncorrected). There was no correlation between MCP and memory. In controls, no significant relationships were identified. These results are consistent with previous literature demonstrating lower FA in younger CHD samples, and provide novel evidence for disrupted white matter integrity in emerging adults with CHD. Furthermore, a correlational double dissociation established distinct white matter circuitry (UF and MCP) and differential cognitive correlates (memory and attention span, respectively) in young adults with CHD.

Characterizing Intraorbital Optic Nerve Changes on Diffusion Tensor Imaging in Thyroid Eye Disease Before Dysthyroid Optic Neuropathy.

PubMed

Lee, Hwa; Lee, Young Hen; Suh, Sang-Il; Jeong, Eun-Kee; Baek, Sehyun; Seo, Hyung Suk

The aim of this study was to determine whether the optic nerve is affected by thyroid eye disease (TED) before the development of dysthyroid optic neuropathy with diffusion-tensor imaging (DTI). Twenty TED patients and 20 controls were included. The mean, axial, and radial diffusivities and fractional anisotropy (FA) value were measured at the optic nerves in DTI. Extraocular muscle diameters were measured on computed tomography. The diffusivities and FA of the optic nerves were compared between TED and controls and between active and inactive stages of TED. The correlations between these DTI parameters and the clinical features were determined. The mean, axial, and radial diffusivities were lower in TED compared with the controls (P < 0.05). In contrast, FA was higher in TED (P = 0.001). Radial diffusivity was lower in the active stage of TED than the inactive stage (P = 0.035). The FA was higher in the TED group than in the control group (P = 0.021) and was positively correlated with clinical activity score (r = 0.364, P = 0.021), modified NOSPECS score (r = 0.469, P = 0.002), and extraocular muscle thickness (r = 0.325, P = 0.041) in the TED group. Radial diffusivity was negatively correlated with modified NOSPECS score (r = -0.384, P = 0.014), and axial diffusivity was positively correlated with exophthalmos degree (r = 0.363, P = 0.025). The diffusivities and FA reflected changes in the optic nerve before dysthyroid optic neuropathy in TED. The FA, in particular, reflected TED activity and severity.

Antimicrobial Activity and Stability of Short and Long Based Arachnid Synthetic Peptides in the Presence of Commercial Antibiotics.

PubMed

Arenas, Ivan; Villegas, Elba; Walls, Oliver; Barrios, Humberto; Rodríguez, Ramon; Corzo, Gerardo

2016-02-17

Four antimicrobial peptides (AMPs) named Pin2[G], Pin2[14], P18K and FA1 were chemically synthesized and purified. The four peptides were evaluated in the presence of eight commercial antibiotics against four microorganisms of medical importance: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae. The commercial antibiotics used were amoxicillin, azithromycin, ceftriaxone, gentamicin, levofloxacin, sulfamethoxazole, trimethoprim and vancomycin. The best AMP against P. aeruginosa was the peptide FA1, and the best AMP against S. aureus was Pin2[G]. Both FA1 and Pin2[G] were efficient against E. coli, but they were not effective against K. pneumoniae. As K. pneumoniae was resistant to most of the commercial antibiotics, combinations of the AMPs FA1 and Pin2[G] were prepared with these antibiotics. According to the fractional inhibitory concentration (FIC) index, the best antimicrobial combinations were obtained with concomitant applications of mixtures of FA1 with levofloxacin and sulfamethoxazole. However, combinations of FA1 or Pin2[G] with other antibiotics showed that total inhibitory effect of the combinations were greater than the sum of the individual effects of either the antimicrobial peptide or the antibiotic. We also evaluated the stability of the AMPs. The AMP Pin2[G] manifested the best performance in saline buffer, in supernatants of bacterial growth and in human blood plasma. Nevertheless, all AMPs were cleaved using endoproteolytic enzymes. These data show advantages and disadvantages of AMPs for potential clinical treatments of bacterial infections, using them in conjunction with commercial antibiotics.

White matter microstructural alterations in children with prenatal methamphetamine/polydrug exposure

PubMed Central

Colby, John B.; Smith, Lynne; O’Connor, Mary J.; Bookheimer, Susan Y.; Van Horn, John D.; Sowell, Elizabeth R.

2013-01-01

Little is known about the effects of prenatal methamphetamine exposure on white matter microstructure, and the impact of concomitant alcohol exposure. Diffusion tensor imaging and neurocognitive testing were performed on 21 children with prenatal methamphetamine exposure (age 9.8±1.8 years; 17 also exposed to alcohol), 19 children with prenatal alcohol but not methamphetamine exposure (age 10.8±2.3 years), and 27 typically-developing children (age 10.3±3.3 years). Whole-brain maps of fractional anisotropy (FA) were evaluated using tract-based spatial statistics. Relative to unexposed controls, children with prenatal methamphetamine exposure demonstrated higher FA mainly in left-sided regions, including the left anterior corona radiata (LCR) and corticospinal tract (P<0.05, corrected). Post-hoc analyses of these FA differences showed they likely result more from lower radial diffusivity (RD) than higher axial diffusivity (AD). Relative to the methamphetamine-exposed group, children with prenatal alcohol exposure showed lower FA in frontotemporal regions – particularly the right external capsule (P<0.05, corrected). We failed to find any group-performance interaction (on tests of executive functioning and visuomotor integration) in predicting FA; however, FA in the right external capsule was significantly associated with performance on a test of visuomotor integration across groups (P<0.05). This report demonstrates unique diffusion abnormalities in children with prenatal methamphetamine/polydrug exposure that are distinct from those associated with alcohol exposure alone, and illustrates that these abnormalities in brain microstructure are persistent into childhood and adolescence – long after the polydrug exposure in utero. PMID:23149028

Diffusion tensor imaging of normal-appearing white matter in mild cognitive impairment and early Alzheimer disease: preliminary evidence of axonal degeneration in the temporal lobe.

PubMed

Huang, J; Friedland, R P; Auchus, A P

2007-01-01

Diffusion tensor imaging (DTI) is a sensitive technique for studying cerebral white matter. We used DTI to characterize microstructural white matter changes and their associations with cognitive dysfunction in Alzheimer disease (AD) and mild cognitive impairment (MCI). We studied elderly subjects with mild AD (n = 6), MCI (n = 11), or normal cognition (n = 8). A standardized clinical and neuropsychological evaluation was conducted on each subject. DTI images were acquired, and fractional anisotropy (FA), axial diffusivity (DA), and radial diffusivity (DR) of normal-appearing white matter (NAWM) in frontal, temporal, parietal, and occipital lobes were determined. These diffusion measurements were compared across the 3 groups, and significant differences were further examined for correlations with tests of cognitive function. Compared with normal controls, AD subjects demonstrated decreased FA and increased DR in the temporal, parietal, and frontal NAWM and decreased DA in temporal NAWM. MCI subjects also showed decreased FA and decreased DA in temporal NAWM, with decreased FA and increased DR in parietal NAWM. Diffusion measurements showed no differences in occipital NAWM. Across all subjects, temporal lobe FA and DR correlated with episodic memory, frontal FA and DR correlated with executive function, and parietal DR significantly correlated with visuospatial ability. We found evidence for functionally relevant microstructural changes in the NAWM of patients with AD and MCI. These changes were present in brain regions serving higher cortical functions, but not in regions serving primary functions, and are consistent with a hypothesized loss of axonal processes in the temporal lobe.

Corpus Callosum Diffusion and Language Lateralization in Patients with Brain Tumors: A DTI and fMRI Study.

PubMed

Tantillo, Gabriella; Peck, Kyung K; Arevalo-Perez, Julio; Lyo, John K; Chou, Joanne F; Young, Robert J; Brennan, Nicole Petrovich; Holodny, Andrei I

2016-01-01

Examining how left-hemisphere brain tumors might impact both the microstructure of the corpus callosum (CC) as measured by fractional anisotropy (FA) values in diffusion tensor imaging (DTI) as well as cortical language lateralization measured with functional MRI (fMRI). fMRI tasks (phonemic fluency and verb generation) were performed in order to detect activation in Broca's and Wernicke's area. Twenty patients with left-hemisphere brain tumors were investigated. fMRI results were divided into left dominant (LD), right dominant (RD), or codominant (CD) for language function. DTI was performed to generate FA maps in the anterior and posterior CC. FA values were correlated with the degree of language dominance. Patients who were LD or RD for language in Broca's area had lower FA in the anterior CC than those who were CD for language (median for CD = .72, LD = .66, RD = .65, P < .09). Lateralized versus CD group level analysis also showed that CD patients had higher FA in the anterior CC than patients who displayed strong lateralization in either hemisphere (median for CD = .72, lateralized = .65, P < .05). Our preliminary observations indicate that the greater FA in CD patients may reflect a more directional microstructure for the CC in this region, suggesting a greater need for interhemispheric transfer of information. Because brain tumors can cause compensatory codominance, our findings may suggest a mechanism by which interhemispheric transfer is facilitated during plasticity in the presence of a tumor. Copyright © 2015 by the American Society of Neuroimaging.

Microstructures in striato-thalamo-orbitofrontal circuit in methamphetamine users.

PubMed

Li, Yadi; Dong, Haibo; Li, Feng; Wang, Gaoyan; Zhou, Wenhua; Yu, Rongbin; Zhang, Lingjun

2017-11-01

Background Striato-thalamo-orbitofrontal (STO) circuit plays a key role in the development of drug addiction. Few studies have investigated its microstructural abnormalities in methamphetamine (MA) users. Purpose To evaluate the microstructural changes and relevant clinical relevance of the STO circuit in MA users using diffusion tensor imaging (DTI). Material and Methods Twenty-eight MA users and 28 age-matched normal volunteers were enrolled. 3T magnetic resonance imaging (MRI) was employed to obtain structural T1-weighted (T1W) imaging and diffusion-tensor imaging (DTI) data. Freesurfer software was used for automated segmentation of the bilateral nucleus accumbens (NAc), thalami, and orbitofrontal cortex (OFC). Four DTI measures maps, fractional anisotropy (FA), mean diffusivity (MD), axial diffusion (AD), and radial diffusion (RD) were generated and non-linearly co-registered to structural space. Comparisons of DTI measures of the STO circuit were carried out between MA and controls using repeated measures analysis of variance. Correlation analyses were performed between STO circuit DTI measures and clinical characteristics. Results The MA group had significant FA reduction in the bilateral NAc, OFC, and right thalamus ( P < 0.05). Lower left OFC FA and right NAc FA/AD were associated with longer duration of MA use. Lower right OFC FA was associated with younger age at first MA use. Higher FA and lower MD/RD in the thalamus, as well as higher left OFC RD, were associated with increased psychiatric symptoms. Conclusion The STO circuit has reduced microstructural integrity in MA users. Microstructural changes in the thalamus may compensate for dysfunction in functionally connected cortices, which needs further investigation.

Non-Linear Association between Cerebral Amyloid Deposition and White Matter Microstructure in Cognitively Healthy Older Adults.

PubMed

Wolf, Dominik; Fischer, Florian U; Scheurich, Armin; Fellgiebel, Andreas

2015-01-01

Cerebral amyloid-β accumulation and changes in white matter (WM) microstructure are imaging characteristics in clinical Alzheimer's disease and have also been reported in cognitively healthy older adults. However, the relationship between amyloid deposition and WM microstructure is not well understood. Here, we investigated the impact of quantitative cerebral amyloid load on WM microstructure in a group of cognitively healthy older adults. AV45-positron emission tomography and diffusion tensor imaging (DTI) scans of forty-four participants (age-range: 60 to 89 years) from the Alzheimer's Disease Neuroimaging Initiative were analyzed. Fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (DR), and axial diffusivity (DA) were calculated to characterize WM microstructure. Regression analyses demonstrated non-linear (quadratic) relationships between amyloid deposition and FA, MD, as well as RD in widespread WM regions. At low amyloid burden, higher deposition was associated with increased FA as well as decreased MD and DR. At higher amyloid burden, higher deposition was associated with decreased FA as well as increased MD and DR. Additional regression analyses demonstrated an interaction effect between amyloid load and global WM FA, MD, DR, and DA on cognition, suggesting that cognition is only affected when amyloid is increasing and WM integrity is decreasing. Thus, increases in FA and decreases in MD and RD with increasing amyloid load at low levels of amyloid burden may indicate compensatory processes that preserve cognitive functioning. Potential mechanisms underlying the observed non-linear association between amyloid deposition and DTI metrics of WM microstructure are discussed.

Gaseous mercury from curing concretes that contain fly ash: laboratory measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Danold W. Golightly; Ping Sun; Chin-Min Cheng

2005-08-01

Total gaseous mercury in headspace air was measured for enclosed concretes dry curing at 40 C for intervals of 2, 28, and 56 days. Release of mercury was confirmed for ordinary Portland cement concrete (OPC) and three concretes in which class F fly ash from coal-combustion substituted for a fraction of the cement: (a) 33% fly ash (FA33), (b) 55% fly ash (FA55), and (c) 33% fly ash plus 0.5% mercury-loaded powdered activated carbon (HgPAC). Mean rates of mercury release (0.10-0.43 ng/day per kg of concrete) over the standard first 28 days of curing followed the order OPC {lt} FA33more » {approximately} FA55 {lt} HgPAC. The mercury flux from exposed surfaces of these concretes ranged from 1.9 {+-} 0.5 to 8.1 {+-} 2.0 ng/m{sup 2}/h, values similar to the average flux for multiple natural substrates in Nevada, 4.2 {+-} 1.4 ng/m{sup 2}/h, recently published by others. Air sampling extending for 28 days beyond the initial 28-day maturation for OPC, FA55, and HgPAC suggested that the average Hg release rate by OPC is constant over 56 days and that mercury release rates for FA55 and HgPAC may ultimately diminish to levels exhibited by OPC concrete. The release of mercury from all samples was less than 0.1% of total mercury content over the initial curing period, implying that nearly all of the mercury was retained in the concrete. 20 refs., 3 figs., 3 tabs.« less

Clinical Significance of Cerebrovascular Biomarkers and White Matter Tract Integrity in Alzheimer Disease: Clinical correlations With Neurobehavioral Data in Cross-Sectional and After 18 Months Follow-ups.

PubMed

Wu, Ming-Kung; Lu, Yan-Ting; Huang, Chi-Wei; Lin, Pin-Hsuan; Chen, Nai-Ching; Lui, Chun-Chung; Chang, Wen-Neng; Lee, Chen-Chang; Chang, Ya-Ting; Chen, Sz-Fan; Chang, Chiung-Chih

2015-07-01

Cerebrovascular risk factors and white matter (WM) damage lead to worse cognitive performance in Alzheimer dementia (AD). This study investigated WM microstructure using diffusion tensor imaging in patients with mild to moderate AD and investigated specific fiber tract involvement with respect to predefined cerebrovascular risk factors and neurobehavioral data prediction cross-sectionally and after 18 months. To identify the primary pathoanatomic relationships of risk biomarkers to fiber tract integrity, we predefined 11 major association tracts and calculated tract specific fractional anisotropy (FA) values. Eighty-five patients with AD underwent neurobehavioral assessments including the minimental state examination (MMSE) and 12-item neuropsychiatric inventory twice with a 1.5-year interval to represent major outcome factors. In the cross-sectional data, total cholesterol, low-density lipoprotein, vitamin B12, and homocysteine levels correlated variably with WM FA values. After entering the biomarkers and WM FA into a regression model to predict neurobehavioral outcomes, only fiber tract FA or homocysteine level predicted the MMSE score, and fiber tract FA or age predicted the neuropsychiatric inventory total scores and subdomains of apathy, disinhibition, and aberrant motor behavior. In the follow-up neurobehavioral data, the mean global FA value predicted the MMSE and aberrant motor behavior subdomain, while age predicted the anxiety and elation subdomains. Cerebrovascular risk biomarkers may modify WM microstructural organization, while the association with fiber integrity showed greater clinical significance to the prediction of neurobehavioral outcomes both cross-sectionally and longitudinally.

White matter microstructural changes in adolescent anorexia nervosa including an exploratory longitudinal study

PubMed Central

Vogel, Katja; Timmers, Inge; Kumar, Vinod; Nickl-Jockschat, Thomas; Bastiani, Matteo; Roebroek, Alard; Herpertz-Dahlmann, Beate; Konrad, Kerstin; Goebel, Rainer; Seitz, Jochen

2016-01-01

Background Anorexia nervosa (AN) often begins in adolescence, however, the understanding of the underlying pathophysiology at this developmentally important age is scarce, impeding early interventions. We used diffusion tensor imaging (DTI) to investigate microstructural white matter (WM) brain changes including an experimental longitudinal follow-up. Methods We acquired whole brain diffusion-weighted brain scans of 22 adolescent female hospitalized patients with AN at admission and nine patients longitudinally at discharge after weight rehabilitation. Patients (10–18 years) were compared to 21 typically developing controls (TD). Tract-based spatial statistics (TBSS) were applied to compare fractional anisotropy (FA) across groups and time points. Associations between average FA values of the global WM skeleton and weight as well as illness duration parameters were analyzed by multiple linear regression. Results We observed increased FA in bilateral frontal, parietal and temporal areas in AN patients at admission compared to TD. Higher FA of the global WM skeleton at admission was associated with faster weight loss prior to admission. Exploratory longitudinal analysis showed this FA increase to be partially normalized after weight rehabilitation. Conclusions Our findings reveal a markedly different pattern of WM microstructural changes in adolescent AN compared to most previous results in adult AN. This could signify a different susceptibility and reaction to semi-starvation in the still developing brain of adolescents or a time-dependent pathomechanism differing with extend of chronicity. Higher FA at admission in adolescents with AN could point to WM fibers being packed together more closely. PMID:27182488

Interhemispheric Difference Images from Postoperative Diffusion Tensor Imaging of Gliomas

PubMed Central

Kosztyla, Robert; Reinsberg, Stefan A; Moiseenko, Vitali; Toyota, Brian

2016-01-01

Introduction Determining the full extent of gliomas during radiotherapy planning can be challenging with conventional T1 and T2 magnetic resonance imaging (MRI). The purpose of this study was to develop a method to automatically calculate differences in the fractional anisotropy (FA) and mean diffusivity (MD) values in target volumes obtained with diffusion tensor imaging (DTI) by comparing with values from anatomically homologous voxels on the contralateral side of the brain. Methods Seven patients with a histologically confirmed glioma underwent postoperative radiotherapy planning with 1.5 T MRI and computed tomography. DTI was acquired using echo planar imaging for 20 noncolinear directions with b = 1000 s/mm2 and one additional image with b = 0, repeated four times for signal averaging. The distribution of FA and MD was calculated in the gross tumor volume (GTV), shells 0-5 mm, 5-10 mm, 10-15 mm, 15-20 mm, and 20-25 mm outside the GTV, and the GTV mirrored in the left-right direction (mirGTV). All images were aligned to a template image, and FA and MD interhemispheric difference images were calculated. The difference in mean FA and MD between the regions of interest was statistically tested using two-sided paired t-tests with α = 0.05. Results The mean FA in mirGTV was 0.20 ± 0.04, which was larger than the FA in the GTV (0.12 ± 0.03) and shells 0-5 mm (0.15 ± 0.03) and 5-10 mm (0.17 ± 0.03) outside the GTV. The mean MD (×10-3 mm2/s) in mirGTV was 0.93 ± 0.09, which was smaller than the MD in the GTV (1.48 ± 0.19) and the peritumoral shells. The distribution of FA and MD interhemispheric differences followed the same trends as FA and MD values. Conclusions This study successfully implemented a method for calculation of FA and MD differences by comparison of voxel values with anatomically homologous voxels on the contralateral side of the brain. Further research is warranted to determine if radiotherapy planning using these images can be used to improve target delineation. PMID:27843735

Microstructural Integrity of the Corpus Callosum Linked with Neuropsychological Performance in Adolescents

ERIC Educational Resources Information Center

Fryer, Susanna L.; Frank, Lawrence R.; Spadoni, Andrea D.; Theilmann, Rebecca J.; Nagel, Bonnie J.; Schweinsburg, Alecia D.; Tapert, Susan F.

2008-01-01

Background: Diffusion tensor imaging (DTI) has revealed microstructural aspects of adolescent brain development, the cognitive correlates of which remain relatively uncharacterized. Methods: DTI was used to assess white matter microstructure in 18 typically developing adolescents (ages 16-18). Fractional anisotropy (FA) and mean diffusion (MD)…

Fluorescence excitation-emission matrix spectroscopy analysis of landfill leachate DOM in coagulation-flocculation process.

PubMed

Zhu, Guocheng; Wang, Chuang; Dong, Xingwei

2017-06-01

Landfill leachate contains a variety of organic matters, some of which can be excited and emit fluorescence signal. In order to degrade these organic matters, the pretreatment of the leachate is needed, which can improve the degradation performance of post-treatment process. Coagulation-flocculation is one of the important pretreatment processes to treat landfill leachate. Assessing the chemical compositions of landfill leachate is helpful in the understanding of their sources and fates as well as the mechanistic behaviors in the water environment. The present work aimed to use fluorescence excitation-emission matrix spectroscopy (EEMs) to characterize the chemical fractions of landfill leachate dissolved organic matter (DOM) in conjunction with parallel factor analysis (PARAFAC). Results showed that the DOM of landfill leachate tested in this study was identified resulting from microbial input, which included five typical characteristic peaks and four kinds of PARAFAC fractions. These fractions were mainly composed of hydrophobic macromolecule humic acid-like (HM-HA), hydrophilic intermediate molecular fulvic acid-like (HIM-FA), and hydrophilic small molecule protein-like substances (HSM-PS). HM-HA and HIM-FA were found to be easier to remove than HSM-PS. Further research on HSM-PS removal by coagulation-flocculation still needs to be improved.

Evaluation of fraction of absorbed photosynthetically active radiation products for different canopy radiation transfer regimes: methodology and results using Joint Research Center products derived from SeaWiFS against ground-based estimations.

Treesearch

Nadine Gobron; Bernard Pinty; Ophélie Aussedat; Jing M. Chen; Warren B. Cohen; Rasmus Fensholt; Valery Gond; Karl Fred Huemmrich; Thomas Lavergne; Frédéric Méline; Jeffrey L. Privette; Inge Sandholt; Malcolm Taberner; David P. Turner; Michael M. Verstraete; Jean-Luc Widlowski

2006-01-01

This paper discusses the quality and the accuracy of the Joint Research Center (JRC) fraction of absorbed photosynthetically active radiation (FAPAR) products generated from an analysis of Sea-viewing Wide Field-of-view Sensor (SeaWiFS) data. The FAPAR value acts as an indicator of the presence and state of the vegetation and it can be estimated from remote sensing...

Determination of the steam volume fraction in the event of loss of cooling of the spent fuel storage pool

NASA Astrophysics Data System (ADS)

Sledkov, R. M.; Galkin, I. Yu.; Stepanov, O. E.; Strebnev, N. A.

2017-01-01

When one solves engineering problems related to the cooling of fuel assemblies (FAs) in a spent fuel storage pool (SFSP) and the assessment of nuclear safety of FA storage in an SFSP in the initial event of loss of SFSP cooling, it is essential to determine the coolant density and, consequently, steam volume fractions φ in bundles of fuel elements at a pressure of 0.1-0.5 MPa. Such formulas for calculating φ that remain valid in a wide range of operating parameters and geometric shapes of channels and take the conditions of loss of SFSP cooling into account are currently almost lacking. The results of systematization and analysis of the available formulas for φ are reported in the present study. The calculated values were compared with the experimental data obtained in the process of simulating the conditions of FA cooling in an SFSP in the event of loss of its cooling. Six formulas for calculating the steam volume fraction, which were used in this comparison, were chosen from a total of 11 considered relations. As a result, the formulas producing the most accurate values of φ in the conditions of loss of SFSP cooling were selected. In addition, a relation that allows one to perform more accurate calculations of steam volume fractions in the conditions of loss of SFSP cooling was derived based on the Fedorov formula in the two-group approximation.

Estimation of crop gross primary production (GPP): fAPAR_chl versus MOD15A2 FPAR

USDA-ARS?s Scientific Manuscript database

Within leaf chloroplasts chlorophylls absorb photosynthetically active radiation (PAR) for photosynthesis (PSN). The MOD15A2 FPAR (fraction of PAR absorbed by canopy, i.e., fAPARcanopy) product has been widely used to compute absorbed PAR for PSN (APARPSN). The MOD17A2 algorithm uses MOD15A2 FPAR i...

Extracellular fluid proteins of goldfish brain: evidence for the presence of proteases and esterases.

PubMed

Shashoua, V E; Holmquist, B

1986-09-01

Preparations of enriched fractions of extracellular fluid (ECF) proteins from goldfish brain were found to contain protease(s) and esterase(s). The N-substituted furanacryloyl (FA) peptides FA-Phe-Gly-Gly and FA-Phe-OMe were used as model substrates for determining protease and esterase activity, respectively, in a spectrophotometric assay. Studies of the profile of substrate specificity and identification of the types of compounds that were effective as inhibitors showed that these ECF enzymes have some distinctive properties. GSH, but not GSSG, and EDTA inhibited the protease(s) without influencing the esterase(s), whereas L-1-tosylamide-2-phenylethylchloromethyl ketone blocked both protease and esterase activities of ECF. Most of the protease and esterase properties of ECF could be bound to concanavalin A-Sepharose affinity chromatographic columns in association with ependymin--a brain extracellular protein. These observations indicate that ECF may contain a metalloprotease(s) and raise the possibility that the ependymins might be a substrate for these ECF enzymes.

Effect of myasthenic patient sera on the number and distribution of acetylcholine receptors in muscle and nerve-muscle cultures from rat. Correlations with clinical state.

PubMed

Eymard, B; de la Porte, S; Pannier, C; Berrih-Aknin, S; Morel, E; Fardeau, M; Bach, J F; Koenig, J

1988-08-01

We studied the functional activities (FA) of sera obtained from 83 myasthenic patients on rat muscle cultures. Using the same sets of cultures, two parameters were evaluated after exposure to sera: residual fraction (RF) of acetylcholine receptors (AChR) coupled to 125I-labelled alpha-bungarotoxin (alpha Bgt) (81 sera) and the number of rhodamine labelled clusters (56 sera). Two types of culture were assayed: muscle alone and nerve-muscle cocultures (12 cases). In all combinations (fluorescence, radiolabelling, muscle alone and nerve-muscle cocultures), we found a significant correlation between FA and antibody (Ab) titre, and no correlation between FA and clinical severity: only sera with a high or intermediate Ab titre were effective, whatever the clinical severity of disease. With active sera, AChR loss was about 50% whereas the disappearance of AChR clusters was quite complete, which suggests AChR redistribution induced by MG sera.

Insight into the heavy metal binding potential of dissolved organic matter in MSW leachate using EEM quenching combined with PARAFAC analysis.

PubMed

Wu, Jun; Zhang, Hua; He, Pin-Jing; Shao, Li-Ming

2011-02-01

Dissolved organic matter (DOM) plays an important role in heavy metal migration from municipal solid waste (MSW) to aquatic environments via the leachate pathway. In this study, fluorescence excitation-emission matrix (EEM) quenching combined with parallel factor (PARAFAC) analysis was adopted to characterize the binding properties of four heavy metals (Cu, Pb, Zn and Cd) and DOM in MSW leachate. Nine leachate samples were collected from various stages of MSW management, including collection, transportation, incineration, landfill and subsequent leachate treatment. Three humic-like components and one protein-like component were identified in the MSW-derived DOM by PARAFAC. Significant differences in quenching effects were observed between components and metal ions, and a relatively consistent trend in metal quenching curves was observed among various leachate samples. Among the four heavy metals, Cu(II) titration led to fluorescence quenching of all four PARAFAC-derived components. Additionally, strong quenching effects were only observed in protein-like and fulvic acid (FA)-like components with the addition of Pb(II), which suggested that these fractions are mainly responsible for Pb(II) binding in MSW-derived DOM. Moreover, the significant quenching effects of the FA-like component by the four heavy metals revealed that the FA-like fraction in MSW-derived DOM plays an important role in heavy metal speciation; therefore, it may be useful as an indicator to assess the potential ability of heavy metal binding and migration. © 2010 Elsevier Ltd. All rights reserved.

Differences in Supratentorial Damage of White Matter in Pediatric Survivors of Posterior Fossa Tumors With and Without Adjuvant Treatment as Detected by Magnetic Resonance Diffusion Tensor Imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rueckriegel, Stefan Mark, E-mail: stefan.rueckriegel@charite.d; Driever, Pablo Hernaiz; Blankenburg, Friederike

2010-03-01

Purpose: To elucidate morphologic correlates of brain dysfunction in pediatric survivors of posterior fossa tumors by using magnetic resonance diffusion tensor imaging (DTI) to examine neuroaxonal integrity in white matter. Patients and Methods: Seventeen medulloblastoma (MB) patients who had received surgery and adjuvant treatment, 13 pilocytic astrocytoma (PA) patients who had been treated only with surgery, and age-matched healthy control subjects underwent magnetic resonance imaging on a 3-Tesla system. High-resolution conventional T1- and T2-weighted magnetic resonance imaging and DTI data sets were obtained. Fractional anisotropy (FA) maps were analyzed using tract-based spatial statistics, a part of the Functional MRI ofmore » the Brain Software Library. Results: Compared with control subjects, FA values of MB patients were significantly decreased in the cerebellar midline structures, in the frontal lobes, and in the callosal body. Fractional anisotropy values of the PA patients were not only decreased in cerebellar hemispheric structures as expected, but also in supratentorial parts of the brain, with a distribution similar to that in MB patients. However, the amount of significantly decreased FA was greater in MB than in PA patients, underscoring the aggravating neurotoxic effect of the adjuvant treatment. Conclusions: Neurotoxic mechanisms that are present in PA patients (e.g., internal hydrocephalus and damaged cerebellar structures affecting neuronal circuits) contribute significantly to the alteration of supratentorial white matter in pediatric posterior fossa tumor patients.« less

Leaching behaviour, mechanical and durability properties of mortar containing municipal incineration bottom ash

NASA Astrophysics Data System (ADS)

Morales Hernandez, Maria B.

The review of municipal solid waste (MSW) management scheme has indicated that the amount of MSW sent to incineration plants will increase in the UK in coming years. Therefore, the amount of municipal solid waste incineration (MSWI) residues generated will increase significantly. MSWI residues are divided into MSWI fly ash (MSWI-FA) and MSWI bottom ash (MSWI-BA). MSWI-FA is classified as hazardous residue thereby requires special treatment before disposal. MSWI-BA is mostly disposed in landfill sites. MSWI-BA fraction with particle size diameter below approximately 2mm has low engineering properties and may have an adverse effect on the environment due to its high porosity, solubility and leachability of possible toxic compounds. This research programme has investigated new potential uses and leaching behaviour of mortar containing MSWI-BA with particle size diameters below 2.36mm. Fraction of MSWI-BA with particle size diameters (φ) below 2.36 mm (φ <2.36) was divided into different sub-fractions to evaluate their influence on compressive strength of concrete when used as partial replacement of cement or sand. MSWI-BA fraction with φ <212mum (fine fraction) and 212mum < φ2.36mm (coarse fraction) used as partial replacement of cement and sand respectively, showed higher compressive strength compared with the other fractions examined. In addition, replacing sand with the coarse fraction of MSWI-BA exhibited similar or higher strength than the reference mix. Examination of physical and chemical properties of the fine and coarse fractions of MSWI-BA unbound indicated that both fractions had potential to be used as replacement of cement or sand. However, the evaluation of their leaching behaviour suggested that they should be bound in cement-based systems to avoid leaching of potential toxic elements. Evaluation of physical, mechanical and sulfate resistance properties of mortars containing 15% of the fine fraction of MSWI-BA as a partial replacement of cement and 50% of the coarse fraction as partial replacement of sand indicated potential uses in concrete production. In addition, the leachability of mortar specimens containing 15% and 50% of MSWI-BA as partial replacement of cement and sand respectively was significantly reduced when compared to unbound MSWI-BA fractions.

Inferring total canopy APAR from PAR bidirectional reflectances and vegetation indices in tallgrass prairie. [Absorbed Photosynthetically Active Radiation

NASA Technical Reports Server (NTRS)

Middleton, Elizabeth M.

1992-01-01

The fraction of photosynthetically active radiation (PAR) absorbed by a vegetated canopy (APARc) or landscape (APARs) is a critical parameter in climate processes. A grassland study examined: 1) whether APARs can be estimated from PAR bidirectional exitance fractions; and 2) whether APARs is correlated with spectral vegetation indices (SVIs). Data were acquired with a high resolution continuous spectroradiometer at 4 sun angles on grassland sites. APARs was computed from the scattered surface PAR exitance fractions. The nadir APARs value was the most variable diurnally; it provided a good estimate of the average surface APARs at 95 percent. APARc was best represented by exitance factors between 30-60* forward.

Characterization of dissolved organic matter in landfill leachate during the combined treatment process of air stripping, Fenton, SBR and coagulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, ZhiPing, E-mail: liulqs@163.com; Faculty of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400020; Wu, WenHui

Highlights: • DOM fractions spectra analysis during the whole treatment process. • Efficient method was achieved to remove organic matters in landfill leachate. • Molecular weight distribution and fractions were discussed. - Abstract: A combined treatment process of air stripping + Fenton + sequencing batch reactor (SBR)+ coagulation was performed to remove the pollutants in landfill leachate. Molecular weight (MW) distribution and fractions of dissolved organic matter (DOM) were discussed to study the characteristics. The experiment showed that the removal rate of chemical oxygen demand (COD), five day biological oxygen demand (BOD{sub 5}) and ammonia nitrogen (NH{sub 3}−N) by themore » combined process were 92.8%, 87.8% and 98.0%, respectively. Humic acid (HA) and fulvic acid (FA) were the main fractions in raw leachate with 81.8% of the total COD concentration, while hydrophilic organic matter (HyI) was the dominant fraction in the final effluent of the combined process with 63.5% of the total COD concentration. After the combined treatment process, the removal rate of DOM and fractions HA, FA, HyI were 91.9%, 97.1%, 95.8% and 71.7%, respectively. Organic matters of MW < 2 k and MW > 100 k were removed with 90.5% and 97.9% COD concentration after the treatment. The ultraviolet–visible spectra (UV–vis), Fourier transform infrared spectra (FTIR) and three-dimensional excitation-emission matrices spectra (EEMs) indicated that benzene materials and phenol compounds were preferentially removed in air stripping. High MW matters, aromatic rings, conjugated moieties and some functional groups were mainly removed by Fenton. While small MW fractions, carboxylic acids, alcohols and protein-like materials were preferentially biodegraded via SBR. Fulvic-like and humic-like materials were mainly destroyed via Fenton oxidation and coagulation.« less

White matter tracts associated with set-shifting in healthy aging.

PubMed

Perry, Michele E; McDonald, Carrie R; Hagler, Donald J; Gharapetian, Lusineh; Kuperman, Joshua M; Koyama, Alain K; Dale, Anders M; McEvoy, Linda K

2009-11-01

Attentional set-shifting ability, commonly assessed with the Trail Making Test (TMT), decreases with increasing age in adults. Since set-shifting performance relies on activity in widespread brain regions, deterioration of the white matter tracts that connect these regions may underlie the age-related decrease in performance. We used an automated fiber tracking method to investigate the relationship between white matter integrity in several cortical association tracts and TMT performance in a sample of 24 healthy adults, 21-80 years. Diffusion tensor images were used to compute average fractional anisotropy (FA) for five cortical association tracts, the corpus callosum (CC), and the corticospinal tract (CST), which served as a control. Results showed that advancing age was associated with declines in set-shifting performance and with decreased FA in the CC and in association tracts that connect frontal cortex to more posterior brain regions, including the inferior fronto-occipital fasciculus (IFOF), uncinate fasciculus (UF), and superior longitudinal fasciculus (SLF). Declines in average FA in these tracts, and in average FA of the right inferior longitudinal fasciculus (ILF), were associated with increased time to completion on the set-shifting subtask of the TMT but not with the simple sequencing subtask. FA values in these tracts were strong mediators of the effect of age on set-shifting performance. Automated tractography methods can enhance our understanding of the fiber systems involved in performance of specific cognitive tasks and of the functional consequences of age-related changes in those systems.

Microstructure and wear characterization of aluminum matrix composites reinforced with industrial waste fly ash particulates synthesized by friction stir processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dinaharan, I., E-mail: dinaweld2009@gmail.com

Fly ash (FA) is a waste product of coal combustion in thermal power plants which is available in massive quantities all over the world causing land pollution. This paper reports the characterization of AA6061 aluminum matrix composites (AMCs) reinforced with FA particles synthesized using friction stir processing (FSP). The volume fraction of FA particles was varied from 0 to 18 in steps of 6. The prepared AMCs were characterized using optical microscopy (OM), scanning electron microscopy (SEM) and electron backscattered diagram (EBSD). The wear rate was estimated using a pin-on-disc wear apparatus. FA particles were observed to be distributed homogeneouslymore » in the AMC irrespective of the location within the stir zone. The EBSD micrographs revealed remarkable grain refinement in the AMC. The incorporation of FA particles enhanced the microhardness and wear resistance of the AMC. The strengthening mechanisms of the AMC were discussed and correlated to the observed microstructures. The wear mechanisms were identified by characterizing the wear debris and worn surfaces. - Highlights: •Industrial waste fly ash was used to produce aluminum matrix composites. •Friction stir processing was used to produce AA6061/Fly Ash composite. •Fly ash particles refined the grains of aluminum matrix. •Fly ash particles enhanced the hardness and wear resistance. •Successful utilization of fly ash to make aluminum composites reduces land pollution.« less

Depressive symptoms and white matter dysfunction in retired NFL players with concussion history.

PubMed

Strain, Jeremy; Didehbani, Nyaz; Cullum, C Munro; Mansinghani, Sethesh; Conover, Heather; Kraut, Michael A; Hart, John; Womack, Kyle B

2013-07-02

To determine whether correlates of white matter integrity can provide general as well as specific insight into the chronic effects of head injury coupled with depression symptom expression in professional football players. We studied 26 retired National Football League (NFL) athletes who underwent diffusion tensor imaging (DTI) scanning. Depressive symptom severity was measured using the Beck Depression Inventory II (BDI-II) including affective, cognitive, and somatic subfactor scores (Buckley 3-factor model). Fractional anisotropy (FA) maps were processed using tract-based spatial statistics from FSL. Correlations between FA and BDI-II scores were assessed using both voxel-wise and region of interest (ROI) techniques, with ROIs that corresponded to white matter tracts. Tracts demonstrating significant correlations were further evaluated using a receiver operating characteristic curve that utilized the mean FA to distinguish depressed from nondepressed subjects. Voxel-wise analysis identified widely distributed voxels that negatively correlated with total BDI-II and cognitive and somatic subfactors, with voxels correlating with the affective component (p < 0.05 corrected) localized to frontal regions. Four tract ROIs negatively correlated (p < 0.01) with total BDI-II: forceps minor, right frontal aslant tract, right uncinate fasciculus, and left superior longitudinal fasciculus. FA of the forceps minor differentiated depressed from nondepressed athletes with 100% sensitivity and 95% specificity. Depressive symptoms in retired NFL athletes correlate negatively with FA using either an unbiased voxel-wise or an ROI-based, tract-wise approach. DTI is a promising biomarker for depression in this population.

A Whole-Brain Investigation of White Matter Microstructure in Adolescents with Conduct Disorder.

PubMed

Sarkar, Sagari; Dell'Acqua, Flavio; Froudist Walsh, Seán; Blackwood, Nigel; Scott, Stephen; Craig, Michael C; Deeley, Quinton; Murphy, Declan G M

2016-01-01

The biological basis of severe antisocial behaviour in adolescents is poorly understood. We recently reported that adolescents with conduct disorder (CD) have significantly increased fractional anisotropy (FA) of the uncinate fasciculus (a white matter (WM) tract that connects the amygdala to the frontal lobe) compared to their non-CD peers. However, the extent of WM abnormality in other brain regions is currently unclear. We used tract-based spatial statistics to investigate whole brain WM microstructural organisation in 27 adolescent males with CD, and 21 non-CD controls. We also examined relationships between FA and behavioural measures. Groups did not differ significantly in age, ethnicity, or substance use history. The CD group, compared to controls, had clusters of significantly greater FA in 7 brain regions corresponding to: 1) the bilateral inferior and superior cerebellar peduncles, corticopontocerebellar tract, posterior limb of internal capsule, and corticospinal tract; 2) right superior longitudinal fasciculus; and 3) left cerebellar WM. Severity of antisocial behavior and callous-unemotional symptoms were significantly correlated with FA in several of these regions across the total sample, but not in the CD or control groups alone. Adolescents with CD have significantly greater FA than controls in WM regions corresponding predominantly to the fronto-cerebellar circuit. There is preliminary evidence that variation in WM microstructure may be dimensionally related to behaviour problems in youngsters. These findings are consistent with the hypothesis that antisocial behaviour in some young people is associated with abnormalities in WM 'connectivity'.

Improvement of Reliability of Diffusion Tensor Metrics in Thigh Skeletal Muscles.

PubMed

Keller, Sarah; Chhabra, Avneesh; Ahmed, Shaheen; Kim, Anne C; Chia, Jonathan M; Yamamura, Jin; Wang, Zhiyue J

2018-05-01

Quantitative diffusion tensor imaging (DTI) of skeletal muscles is challenging due to the bias in DTI metrics, such as fractional anisotropy (FA) and mean diffusivity (MD), related to insufficient signal-to-noise ratio (SNR). This study compares the bias of DTI metrics in skeletal muscles via pixel-based and region-of-interest (ROI)-based analysis. DTI of the thigh muscles was conducted on a 3.0-T system in N = 11 volunteers using a fat-suppressed single-shot spin-echo echo planar imaging (SS SE-EPI) sequence with eight repetitions (number of signal averages (NSA) = 4 or 8 for each repeat). The SNR was calculated for different NSAs and estimated for the composite images combining all data (effective NSA = 48) as standard reference. The bias of MD and FA derived by pixel-based and ROI-based quantification were compared at different NSAs. An "intra-ROI diffusion direction dispersion angle (IRDDDA)" was calculated to assess the uniformity of diffusion within the ROI. Using our standard reference image with NSA = 48, the ROI-based and pixel-based measurements agreed for FA and MD. Larger disagreements were observed for the pixel-based quantification at NSA = 4. MD was less sensitive than FA to the noise level. The IRDDDA decreased with higher NSA. At NSA = 4, ROI-based FA showed a lower average bias (0.9% vs. 37.4%) and narrower 95% limits of agreement compared to the pixel-based method. The ROI-based estimation of FA is less prone to bias than the pixel-based estimations when SNR is low. The IRDDDA can be applied as a quantitative quality measure to assess reliability of ROI-based DTI metrics. Copyright © 2018 Elsevier B.V. All rights reserved.

White matter microstructural variability mediates the relation between obesity and cognition in healthy adults.

PubMed

Zhang, Rui; Beyer, Frauke; Lampe, Leonie; Luck, Tobias; Riedel-Heller, Steffi G; Loeffler, Markus; Schroeter, Matthias L; Stumvoll, Michael; Villringer, Arno; Witte, A Veronica

2018-05-15

Obesity has been linked with structural and functional brain changes. However, the impact of obesity on brain and cognition in aging remains debatable, especially for white matter. We therefore aimed to determine the effects of obesity on white matter microstructure and potential implications for cognition in a well-characterized large cohort of healthy adults. In total, 1255 participants (50% females, 19-80 years, BMI 16.8-50.2 kg/m 2 ) with diffusion-weighted magnetic resonance imaging at 3T were analysed. Tract-based spatial statistics (TBSS) probed whether body mass index (BMI) and waist-to-hip ratio (WHR) were related to fractional anisotropy (FA). We conducted partial correlations and mediation analyses to explore whether obesity or regional FA were related to cognitive performance. Analyses were adjusted for demographic, genetic, and obesity-associated confounders. Results showed that higher BMI and higher WHR were associated with lower FA in multiple white matter tracts (p < 0.05, FWE-corrected). Mediation analyses provided evidence for indirect negative effects of higher BMI and higher WHR on executive functions and processing speed through lower FA in fiber tracts connecting (pre)frontal, visual, and associative areas (indirect paths, |ß| ≥ 0.01; 99% |CI| > 0). This large cross-sectional study showed that obesity is correlated with lower FA in multiple white matter tracts in otherwise healthy adults, independent of confounders. Moreover, although effect sizes were small, mediation results indicated that visceral obesity was linked to poorer executive functions and lower processing speed through lower FA in callosal and associative fiber tracts. Longitudinal studies are needed to support this hypothesis. Copyright © 2018 Elsevier Inc. All rights reserved.

Brain–Computer Interface Training after Stroke Affects Patterns of Brain–Behavior Relationships in Corticospinal Motor Fibers

PubMed Central

Young, Brittany M.; Stamm, Julie M.; Song, Jie; Remsik, Alexander B.; Nair, Veena A.; Tyler, Mitchell E.; Edwards, Dorothy F.; Caldera, Kristin; Sattin, Justin A.; Williams, Justin C.; Prabhakaran, Vivek

2016-01-01

Background: Brain–computer interface (BCI) devices are being investigated for their application in stroke rehabilitation, but little is known about how structural changes in the motor system relate to behavioral measures with the use of these systems. Objective: This study examined relationships among diffusion tensor imaging (DTI)-derived metrics and with behavioral changes in stroke patients with and without BCI training. Methods: Stroke patients (n = 19) with upper extremity motor impairment were assessed using Stroke Impact Scale (SIS), Action Research Arm Test (ARAT), Nine-Hole Peg Test (9-HPT), and DTI scans. Ten subjects completed four assessments over a control period during which no training was administered. Seventeen subjects, including eight who completed the control period, completed four assessments over an experimental period during which subjects received interventional BCI training. Fractional anisotropy (FA) values were extracted from each corticospinal tract (CST) and transcallosal motor fibers for each scan. Results: No significant group by time interactions were identified at the group level in DTI or behavioral measures. During the control period, increases in contralesional CST FA and in asymmetric FA (aFA) correlated with poorer scores on SIS and 9-HPT. During the experimental period (with BCI training), increases in contralesional CST FA were correlated with improvements in 9-HPT while increases in aFA correlated with improvements in ARAT but with worsening 9-HPT performance; changes in transcallosal motor fibers positively correlated with those in the contralesional CST. All correlations p < 0.05 corrected. Conclusion: These findings suggest that the integrity of the contralesional CST may be used to track individual behavioral changes observed with BCI training after stroke. PMID:27695404

Sex differences in white matter abnormalities after mild traumatic brain injury: localization and correlation with outcome.

PubMed

Fakhran, Saeed; Yaeger, Karl; Collins, Michael; Alhilali, Lea

2014-09-01

To evaluate sex differences in diffusion-tensor imaging (DTI) white matter abnormalities after mild traumatic brain injury (mTBI) using tract-based spatial statistics (TBSS) and to compare associated clinical outcomes. The institutional review board approved this study, with waiver of informed consent. DTI in 69 patients with mTBI (47 male and 22 female patients) and 21 control subjects (10 male and 11 female subjects) with normal conventional magnetic resonance (MR) images were retrospectively reviewed. Fractional anisotropy (FA) maps were generated as a measure of white matter integrity. Patients with mTBI underwent serial neurocognitive testing with Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT). Correlation between sex, white matter FA values, ImPACT scores, and time to symptom resolution (TSR) were analyzed with multivariate analysis and TBSS. No significant difference in age was seen between males and females (control subjects, P = .3; patients with mTBI, P = .34). No significant difference was seen in initial ImPACT symptom scores (P = .33) between male and female patients with mTBI. Male patients with mTBI had significantly decreased FA values in the uncinate fasciculus (UF) bilaterally (mean FA, 0.425; 95% confidence interval: 0.375, 0.476) compared with female patients with mTBI and control subjects (P < .05), with a significantly longer TSR (P = .04). Multivariate analysis showed sex and UF FA values independently correlated with TSR longer than 3 months (adjusted odds ratios, 2.27 and 2.38; P = .04 and P < .001, respectively), but initial symptom severity did not (adjusted odds ratio, 1.15; P = .35). Relative sparing of the UF is seen in female compared with male patients after mTBI, with sex and UF FA values as stronger predictors of TSR than initial symptom severity.

White matter integrity, hippocampal volume, and cognitive performance of a world-famous nonagenarian track-and-field athlete.

PubMed

Burzynska, A Z; Wong, C N; Chaddock-Heyman, L; Olson, E A; Gothe, N P; Knecht, A; Voss, M W; McAuley, E; Kramer, A F

2016-01-01

Physical activity (PA) and cardiorespiratory fitness (CRF) are associated with successful brain and cognitive aging. However, little is known about the effects of PA, CRF, and exercise on the brain in the oldest-old. Here we examined white matter (WM) integrity, measured as fractional anisotropy (FA) and WM hyperintensity (WMH) burden, and hippocampal (HIPP) volume of Olga Kotelko (1919-2014). Olga began training for competitions at age of 77 and as of June 2014 held over 30 world records in her age category in track-and-field. We found that Olga's WMH burden was larger and the HIPP was smaller than in the reference sample (58 healthy low-active women 60-78 years old), and her FA was consistently lower in the regions overlapping with WMH. Olga's FA in many normal-appearing WM regions, however, did not differ or was greater than in the reference sample. In particular, FA in her genu corpus callosum was higher than any FA value observed in the reference sample. We speculate that her relatively high FA may be related to both successful aging and the beneficial effects of exercise in old age. In addition, Olga had lower scores on memory, reasoning and speed tasks than the younger reference sample, but outperformed typical adults of age 90-95 on speed and memory. Together, our findings open the possibility of old-age benefits of increasing PA on WM microstructure and cognition despite age-related increase in WMH burden and HIPP shrinkage, and add to the still scarce neuroimaging data of the healthy oldest-old (>90 years) adults.

Comparison of Single-Shot Echo-Planar and Line Scan Protocols for Diffusion Tensor Imaging1

PubMed Central

Kubicki, Marek; Maier, Stephan E.; Westin, Carl-Frederik; Mamata, Hatsuho; Ersner-Hershfield, Hal; Estepar, Raul; Kikinis, Ron; Jolesz, Ferenc A.

2009-01-01

Rationale and Objectives Both single-shot diffusion-weighted echo-planar imaging (EPI) and line scan diffusion imaging (LSDI) can be used to obtain magnetic resonance diffusion tensor data and to calculate directionally invariant diffusion anisotropy indices, ie, indirect measures of the organization and coherence of white matter fibers in the brain. To date, there has been no comparison of EPI and LSDI. Because EPI is the most commonly used technique for acquiring diffusion tensor data, it is important to understand the limitations and advantages of LSDI relative to EPI. Materials and Methods Five healthy volunteers underwent EPI and LSDI diffusion on a 1.5 Tesla magnet (General Electric Medical Systems, Milwaukee, WI). Four-mm thick coronal sections, covering the entire brain, were obtained. In addition, one subject was tested with both sequences over four sessions. For each image voxel, eigenvectors and eigenvalues of the diffusion tensor were calculated, and fractional anisotropy (FA) was derived. Several regions of interest were delineated, and for each, mean FA and estimated mean standard deviation were calculated and compared. Results Results showed no significant differences between EPI and LSDI for mean FA for the five subjects. When inter-session reproducibility for one subject was evaluated, there was a significant difference between EPI and LSDI in FA for the corpus callosum and the right uncinate fasciculus. Moreover, errors associated with each FA measure were larger for EPI than for LSDI. Conclusion Results indicate that both EPI- and LSDI-derived FA measures are sufficiently robust. However, when higher accuracy is needed, LSDI provides smaller error and smaller inter-subject and inter-session variability than EPI. PMID:14974598

Aortic Stiffness, Increased White Matter Free Water, and Altered Microstructural Integrity: A Continuum of Injury.

PubMed

Maillard, Pauline; Mitchell, Gary F; Himali, Jayandra J; Beiser, Alexa; Fletcher, Evan; Tsao, Connie W; Pase, Matthew P; Satizabal, Claudia L; Vasan, Ramachandran S; Seshadri, Sudha; DeCarli, Charles

2017-06-01

Previous reports from the Framingham Heart Study have identified cross-sectional associations of arterial stiffness, as reflected by carotid-femoral pulse wave velocity (CFPWV) and systolic blood pressure with vascular brain injury. The purpose of this study is to examine free water (FW), fractional anisotropy (FA), and white matter hyperintensities (WMH) in relation to arterial stiffness among subjects of the Framingham Offspring and Third-Generation cohorts. In 2422 participants aged 51.3±11.6 years, FA, FW, and WMH were related to CFPWV using voxel-based linear and generalized linear regressions, adjusting for relevant covariables. Mean FW, mean FA, and WMH burden (log transformed) were computed within white matter (WM) region and related to systolic blood pressure and CFPWV using multiple mediation analyses. CFPWV was found to be associated with higher FW, lower FA, and higher WMH incidence in WM areas covering, respectively, 356.1, 211.8, and 10.9 mL of the WM mask. Mediation analyses revealed that the effect of systolic blood pressure on FW was mediated by CFPWV (direct and indirect effects: a=0.040; P <0.001, and a'=0.020; P >0.05). Moreover, the effect of CFPWV on FA was mediated by FW (direct and indirect effects: b=-0.092; P <0.001, and b'=0.012; P >0.05), whose effect on WMH was, in turn, mediated by FA (direct and indirect effects: c=0.246; P <0.001, and c'=0.116; P >0.05). From these data, we propose a biomechanical hypothesis designed for future research experiments to explain how hemodynamic alteration may lead to WM injury by impacting cerebral water content and more subtly WM integrity, to finally lead to WMH development. © 2017 American Heart Association, Inc.

Role of diffusion tensor imaging or magnetic resonance spectroscopy in the diagnosis and disability assessment of amyotrophic lateral sclerosis.

PubMed

Liu, Chanchan; Jiang, Rifeng; Yi, Xiyan; Zhu, Wenzhen; Bu, Bitao

2015-01-15

To compare the results of magnetic resonance spectroscopy (MRS) and diffusion tensor imaging (DTI) in amyotrophic lateral sclerosis (ALS) patients. Nineteen ALS patients and thirteen age-matched healthy controls underwent MRS and DTI between October 2013 and July 2014. Fractional anisotropy (FA), apparent diffusion coefficient (ADC), N-acetylaspartate (NAA), choline (Cho), and creatine (Cr) were collected as the quantitative results of the imaging study. The ALS functional rating scale-revised (ALSFRS-R) and disease progression rate were evaluated to assess patients' disability. The imaging study results were compared between ALS patients and healthy controls. The relationship between disability assessment and imaging study results was analyzed. NAA/Cr in the motor cortex and FA in the corticospinal tract (CST) of both sides were significantly lower in patients than controls. There was no significant difference between the two groups in Cho/Cr, tract length, tract volume, ADC or NAA. No relationship was found between ALSFRS-R and FA (r=0.243, p=0.316) in the right CST; NAA (r=0.095, p=0.699) or NAA/Cr (r=0.172, p=0.481) in the left motor cortex; or NAA (r=0.320, p=0.182) or NAA/Cr (r=0.193, p=0.492) in the right motor cortex. There was no relationship between the disease progression rate and FA, NAA, or NAA/Cr on either side. NAA/Cr and FA can help diagnose ALS. Regional brain NAA/Cr and FA values could not assess the ALSFRS-R or disease progression rate. Copyright © 2014 Elsevier B.V. All rights reserved.

Genetic Study of White Matter Integrity in UK Biobank (N=8448) and the Overlap With Stroke, Depression, and Dementia.

PubMed

Rutten-Jacobs, Loes C A; Tozer, Daniel J; Duering, Marco; Malik, Rainer; Dichgans, Martin; Markus, Hugh S; Traylor, Matthew

2018-06-01

Structural integrity of the white matter is a marker of cerebral small vessel disease, which is the major cause of vascular dementia and a quarter of all strokes. Genetic studies provide a way to obtain novel insights in the disease mechanism underlying cerebral small vessel disease. The aim was to identify common variants associated with microstructural integrity of the white matter and to elucidate the relationships of white matter structural integrity with stroke, major depressive disorder, and Alzheimer disease. This genome-wide association analysis included 8448 individuals from UK Biobank-a population-based cohort study that recruited individuals from across the United Kingdom between 2006 and 2010, aged 40 to 69 years. Microstructural integrity was measured as fractional anisotropy- (FA) and mean diffusivity (MD)-derived parameters on diffusion tensor images. White matter hyperintensity volumes (WMHV) were assessed on T2-weighted fluid-attenuated inversion recovery images. We identified 1 novel locus at genome-wide significance ( VCAN [versican]: rs13164785; P =3.7×10 -18 for MD and rs67827860; P =1.3×10 -14 for FA). LD score regression showed a significant genome-wide correlation between FA, MD, and WMHV (FA-WMHV rG 0.39 [SE, 0.15]; MD-WMHV rG 0.56 [SE, 0.19]). In polygenic risk score analysis, FA, MD, and WMHV were significantly associated with lacunar stroke, MD with major depressive disorder, and WMHV with Alzheimer disease. Genetic variants within the VCAN gene may play a role in the mechanisms underlying microstructural integrity of the white matter in the brain measured as FA and MD. Mechanisms underlying white matter alterations are shared with cerebrovascular disease, and inherited differences in white matter microstructure impact on Alzheimer disease and major depressive disorder. © 2018 The Authors.

Impact of blood flow on diffusion coefficients of the human kidney: a time-resolved ECG-triggered diffusion-tensor imaging (DTI) study at 3T.

PubMed

Heusch, Philipp; Wittsack, Hans-Jörg; Kröpil, Patric; Blondin, Dirk; Quentin, Michael; Klasen, Janina; Pentang, Gael; Antoch, Gerald; Lanzman, Rotem S

2013-01-01

To evaluate the impact of renal blood flow on apparent diffusion coefficients (ADC) and fractional anisotropy (FA) using time-resolved electrocardiogram (ECG)-triggered diffusion-tensor imaging (DTI) of the human kidneys. DTI was performed in eight healthy volunteers (mean age 29.1 ± 3.2) using a single slice coronal echoplanar imaging (EPI) sequence (3 b-values: 0, 50, and 300 s/mm(2)) at the timepoint of minimum (20 msec after R wave) and maximum renal blood flow (200 msec after R wave) at 3T. Following 2D motion correction, region of interest (ROI)-based analysis of cortical and medullary ADC- and FA-values was performed. ADC-values of the renal cortex at maximum blood flow (2.6 ± 0.19 × 10(-3) mm(2)/s) were significantly higher than at minimum blood flow (2.2 ± 0.11 × 10(-3) mm(2)/s) (P < 0.001), while medullary ADC-values did not differ significantly (maximum blood flow: 2.2 ± 0.18 × 10(-3) mm(2)/s; minimum blood flow: 2.15 ± 0.14 × 10(-3) mm(2)/s). FA-values of the renal medulla were significantly greater at maximal blood (0.53 ± 0.05) than at minimal blood flow (0.47 ± 0.05) (P < 0.01). In contrast, cortical FA-values were comparable at different timepoints of the cardiac cycle. ADC-values in the renal cortex as well as FA-values in the renal medulla are influenced by renal blood flow. This impact has to be considered when interpreting renal ADC- and FA-values. Copyright © 2012 Wiley Periodicals, Inc.

The impact of white matter fiber orientation in single-acquisition quantitative susceptibility mapping.

PubMed

Lancione, Marta; Tosetti, Michela; Donatelli, Graziella; Cosottini, Mirco; Costagli, Mauro

2017-11-01

The aim of this work was to assess the impact of tissue structural orientation on quantitative susceptibility mapping (QSM) reliability, and to provide a criterion to identify voxels in which measures of magnetic susceptibility (χ) are most affected by spatial orientation effects. Four healthy volunteers underwent 7-T magnetic resonance imaging (MRI). Multi-echo, gradient-echo sequences were used to obtain quantitative maps of frequency shift (FS) and χ. Information from diffusion tensor imaging (DTI) was used to investigate the relationship between tissue orientation and FS measures and QSM. After sorting voxels on the basis of their fractional anisotropy (FA), the variations in FS and χ values over tissue orientation were measured. Using a K-means clustering algorithm, voxels were separated into two groups depending on the variability of measures within each FA interval. The consistency of FS and QSM values, observed at low FA, was disrupted for FA > 0.6. The standard deviation of χ measured at high FA (0.0103 ppm) was nearly five times that at low FA (0.0022 ppm). This result was consistent through data across different head positions and for different brain regions considered separately, which confirmed that such behavior does not depend on structures with different bulk susceptibility oriented along particular angles. The reliability of single-orientation QSM anticorrelates with local FA. QSM provides replicable values with little variability in brain regions with FA < 0.6, but QSM should be interpreted cautiously in major and coherent fiber bundles, which are strongly affected by structural anisotropy and magnetic susceptibility anisotropy. Copyright © 2017 John Wiley & Sons, Ltd.

Structural integrity of the contralesional hemisphere predicts cognitive impairment in ischemic stroke at three months.

PubMed

Dacosta-Aguayo, Rosalia; Graña, Manuel; Fernández-Andújar, Marina; López-Cancio, Elena; Cáceres, Cynthia; Bargalló, Núria; Barrios, Maite; Clemente, Immaculada; Monserrat, Pere Toran; Sas, Maite Alzamora; Dávalos, Antoni; Auer, Tibor; Mataró, Maria

2014-01-01

After stroke, white matter integrity can be affected both locally and distally to the primary lesion location. It has been shown that tract disruption in mirror's regions of the contralateral hemisphere is associated with degree of functional impairment. Fourteen patients suffering right hemispheric focal stroke (S) and eighteen healthy controls (HC) underwent Diffusion Weighted Imaging (DWI) and neuropsychological assessment. The stroke patient group was divided into poor (SP; n = 8) and good (SG; n = 6) cognitive recovery groups according to their cognitive improvement from the acute phase (72 hours after stroke) to the subacute phase (3 months post-stroke). Whole-brain DWI data analysis was performed by computing Diffusion Tensor Imaging (DTI) followed by Tract Based Spatial Statistics (TBSS). Assessment of effects was obtained computing the correlation of the projections on TBSS skeleton of Fractional Anisotropy (FA) and Radial Diffusivity (RD) with cognitive test results. Significant decrease of FA was found only in right brain anatomical areas for the S group when compared to the HC group. Analyzed separately, stroke patients with poor cognitive recovery showed additional significant FA decrease in several left hemisphere regions; whereas SG patients showed significant decrease only in the left genu of corpus callosum when compared to the HC. For the SG group, whole brain analysis revealed significant correlation between the performance in the Semantic Fluency test and the FA in the right hemisphere as well as between the performance in the Grooved Pegboard Test (GPT) and the Trail Making Test-part A and the FA in the left hemisphere. For the SP group, correlation analysis revealed significant correlation between the performance in the GPT and the FA in the right hemisphere.

White matter organization in cervical spinal cord relates differently to age and control of grip force in healthy subjects.

PubMed

Lindberg, Påvel G; Feydy, Antoine; Maier, Marc A

2010-03-17

Diffusion tensor imaging (DTI) can be used to elucidate relations between CNS structure and function. We hypothesized that the degree of spinal white matter organization relates to the accuracy of control of grip force. Healthy subjects of different age were studied using DTI and visuomotor tracking of precision grip force. The latter is a prime component of manual dexterity. A regional analysis of spinal white matter [fractional anisotropy (FA)] across multiple cervical levels (C2-C3, C4-C5, and C6-C7) and in different regions of interest (left and right lateral or medial spinal cord) was performed. FA was highest at the C2-C3 level, higher on the right than the left side, and higher in the lateral than in the medial spinal cord (p < 0.001). FA of whole cervical spinal cord (C2-C7) was lower in subjects with high tracking error (r = -0.56, p = 0.004) and decreased with age (r = -0.63, p = 0.001). A multiple regression analysis revealed an independent contribution of each predictor (semipartial correlations: age, r = -0.55, p < 0.001; tracking error, r = -0.49, p = 0.003). The closest relation between FA and tracking error was found at the C6-C7 level in the lateral spinal cord, in which the corticospinal tract innervates spinal circuitry controlling hand and digit muscles. FA of the medial spinal cord correlated consistently with age across all cervical levels, whereas FA of the lateral spinal cord did not. The results suggest (1) a functionally relevant specialization of lateral spinal cord white matter and (2) an increased sensitivity to age-related decline in medial spinal cord white matter in healthy subjects.

Structural Integrity of the Contralesional Hemisphere Predicts Cognitive Impairment in Ischemic Stroke at Three Months

PubMed Central

Dacosta-Aguayo, Rosalia; Graña, Manuel; Fernández-Andújar, Marina; López-Cancio, Elena; Cáceres, Cynthia; Bargalló, Núria; Barrios, Maite; Clemente, Immaculada; Monserrat, Pere Toran; Sas, Maite Alzamora; Dávalos, Antoni

2014-01-01

After stroke, white matter integrity can be affected both locally and distally to the primary lesion location. It has been shown that tract disruption in mirror’s regions of the contralateral hemisphere is associated with degree of functional impairment. Fourteen patients suffering right hemispheric focal stroke (S) and eighteen healthy controls (HC) underwent Diffusion Weighted Imaging (DWI) and neuropsychological assessment. The stroke patient group was divided into poor (SP; n = 8) and good (SG; n = 6) cognitive recovery groups according to their cognitive improvement from the acute phase (72 hours after stroke) to the subacute phase (3 months post-stroke). Whole-brain DWI data analysis was performed by computing Diffusion Tensor Imaging (DTI) followed by Tract Based Spatial Statistics (TBSS). Assessment of effects was obtained computing the correlation of the projections on TBSS skeleton of Fractional Anisotropy (FA) and Radial Diffusivity (RD) with cognitive test results. Significant decrease of FA was found only in right brain anatomical areas for the S group when compared to the HC group. Analyzed separately, stroke patients with poor cognitive recovery showed additional significant FA decrease in several left hemisphere regions; whereas SG patients showed significant decrease only in the left genu of corpus callosum when compared to the HC. For the SG group, whole brain analysis revealed significant correlation between the performance in the Semantic Fluency test and the FA in the right hemisphere as well as between the performance in the Grooved Pegboard Test (GPT) and theTrail Making Test-part A and the FA in the left hemisphere. For the SP group, correlation analysis revealed significant correlation between the performance in the GPT and the FA in the right hemisphere. PMID:24475078

Analysis of correlation between white matter changes and functional responses in thalamic stroke: a DTI & EEG study.

PubMed

Duru, Adil Deniz; Duru, Dilek Göksel; Yumerhodzha, Sami; Bebek, Nerses

2016-06-01

Diffusion tensor imaging (DTI) allows in vivo structural brain mapping and detection of microstructural disruption of white matter (WM). One of the commonly used parameters for grading the anisotropic diffusivity in WM is fractional anisotropy (FA). FA value helps to quantify the directionality of the local tract bundle. Therefore, FA images are being used in voxelwise statistical analyses (VSA). The present study used Tract-Based Spatial Statistics (TBSS) of FA images across subjects, and computes the mean skeleton map to detect voxelwise knowledge of the tracts yielding to groupwise comparison. The skeleton image illustrates WM structure and shows any changes caused by brain damage. The microstructure of WM in thalamic stroke is investigated, and the VSA results of healthy control and thalamic stroke patients are reported. It has been shown that several skeleton regions were affected subject to the presence of thalamic stroke (FWE, p < 0.05). Furthermore the correlation of quantitative EEG (qEEG) scores and neurophysiological tests with the FA skeleton for the entire test group is also investigated. We compared measurements that are related to the same fibers across subjects, and discussed implications for VSA of WM in thalamic stroke cases, for the relationship between behavioral tests and FA skeletons, and for the correlation between the FA maps and qEEG scores.Results obtained through the regression analyses did not exceed the corrected statistical threshold values for multiple comparisons (uncorrected, p < 0.05). However, in the regression analysis of FA values and the theta band activity of EEG, cingulum bundle and corpus callosum were found to be related. These areas are parts of the Default Mode Network (DMN) where DMN is known to be involved in resting state EEG theta activity. The relation between the EEG alpha band power values and FA values of the skeleton was found to support the cortico-thalamocortical cycles for both subject groups. Further, the neurophysiological tests including Benton Face Recognition (BFR), Digit Span test (DST), Warrington Topographic Memory test (WTMT), California Verbal Learning test (CVLT) has been regressed with the FA skeleton maps for both subject groups. Our results corresponding to DST task were found to be similar with previously reported findings for working memory and episodic memory tasks. For the WTMT, FA values of the cingulum (right) that plays a role in memory process was found to be related with the behavioral responses. Splenium of corpus callosum was found to be correlated for both subject groups for the BFR.

White Matter Microstructure in Subjects with Attention-Deficit/Hyperactivity Disorder and Their Siblings

ERIC Educational Resources Information Center

Lawrence, Katherine E.; Levitt, Jennifer G.; Loo, Sandra K.; Ly, Ronald; Yee, Victor; O'Neill, Joseph; Alger, Jeffry; Narr, Katherine L.

2013-01-01

Objective: Previous voxel-based and regions-of-interest (ROI)-based diffusion tensor imaging (DTI) studies have found above-normal mean diffusivity (MD) and below-normal fractional anisotropy (FA) in subjects with attention-deficit/hyperactivity disorder (ADHD). However, findings remain mixed, and few studies have examined the contribution of ADHD…

Cognitive Impairment and Whole Brain Diffusion in Patients with Neuromyelitis Optica after Acute Relapse

ERIC Educational Resources Information Center

He, Diane; Wu, Qizhu; Chen, Xiuying; Zhao, Daidi; Gong, Qiyong; Zhou, Hongyu

2011-01-01

The objective of this study investigated cognitive impairments and their correlations with fractional anisotropy (FA) and mean diffusivity (MD) in patients with neuromyelitis optica (NMO) without visible lesions on conventional brain MRI during acute relapse. Twenty one patients with NMO and 21 normal control subjects received several cognitive…

Diffusion tensor imaging of nigral degeneration in Parkinson's disease: A region-of-interest and voxel-based study at 3 T and systematic review with meta-analysis☆

PubMed Central

Schwarz, Stefan T.; Abaei, Maryam; Gontu, Vamsi; Morgan, Paul S.; Bajaj, Nin; Auer, Dorothee P.

2013-01-01

There is increasing interest in developing a reliable, affordable and accessible disease biomarker of Parkinson's disease (PD) to facilitate disease modifying PD-trials. Imaging biomarkers using magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) can describe parameters such as fractional anisotropy (FA), mean diffusivity (MD) or apparent diffusion coefficient (ADC). These parameters, when measured in the substantia nigra (SN), have not only shown promising but also varying and controversial results. To clarify the potential diagnostic value of nigral DTI in PD and its dependency on selection of region-of-interest, we undertook a high resolution DTI study at 3 T. 59 subjects (32 PD patients, 27 age and sex matched healthy controls) were analysed using manual outlining of SN and substructures, and voxel-based analysis (VBA). We also performed a systematic literature review and meta-analysis to estimate the effect size (DES) of disease related nigral DTI changes. We found a regional increase in nigral mean diffusivity in PD (mean ± SD, PD 0.80 ± 0.10 vs. controls 0.73 ± 0.06 · 10− 3 mm2/s, p = 0.002), but no difference using a voxel based approach. No significant disease effect was seen using meta-analysis of nigral MD changes (10 studies, DES = + 0.26, p = 0.17, I2 = 30%). None of the nigral regional or voxel based analyses of this study showed altered fractional anisotropy. Meta-analysis of 11 studies on nigral FA changes revealed a significant PD induced FA decrease. There was, however, a very large variation in results (I2 = 86%) comparing all studies. After exclusion of five studies with unusual high values of nigral FA in the control group, an acceptable heterogeneity was reached, but there was non-significant disease effect (DES = − 0.5, p = 0.22, I2 = 28%). The small PD related nigral MD changes in conjunction with the negative findings on VBA and meta-analysis limit the usefulness of nigral MD measures as biomarker of Parkinson's disease. The negative results of nigral FA measurements at regional, sub-regional and voxel level in conjunction with the results of the meta-analysis of nigral FA changes question the stability and validity of this measure as a PD biomarker. PMID:24273730

Rapid Detection and Identification of Respiratory Viruses by Direct Immunofluorescence

PubMed Central

D'Alessio, Donn; Williams, Stanley; Dick, Elliot C.

1970-01-01

The use of fluorescein-conjugated antiserum against respiratory syncytial (RS) and parainfluenza 1 and 3 viruses was compared with conventional techniques in the rapid detection of virus in tissue cultures inoculated with pharyngeal specimens known to contain these viruses. Twenty-three specimens were tested: 9 RS, 8 parainfluenza 1, and 6 parainfluenza 3. The fluorescent-antibody technique (FA) detected virus in 52% of the tissue cultures in 24 hr, and, by 72 hr, 22 of the 23 cultures were FA-positive whereas only 5 were positive by conventional techniques. Additionally, conjugated antisera were prepared against herpes simplex, influenza A2, and adenovirus type 5. All conjugates stained only the homologous virus and were 100- to 10,000-fold more sensitive than conventional techniques in detecting descending dilutions of virus inocula by 24 hr. With the procedures described, several antisera could be conjugated and ready for use within 24 hr. Serum fractionation was by ammonium sulfate precipitation, and with the procedure outlined virtually complete recovery of the globulin fraction and elimination of all of the albumin were accomplished. Images PMID:4098101

SU-E-J-212: MR Diffusion Tensor Imaging for Assessment of Tumor and Normal Brain Tissue Responses of Juvenile Pilocytic Astrocytoma Treated by Proton Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hou, P; Park, P; Li, H

Purpose: Diffusion tensor imaging (DTI) can measure molecular mobility at the cellular level, quantified by the apparent diffusion coefficient (ADC). DTI may also reveal axonal fiber directional information in the white matter, quantified by the fractional anisotropy (FA). Juvenile pilocytic astrocytoma (JPA) is a rare brain tumor that occurs in children and young adults. Proton therapy (PT) is increasingly used in the treatment of pediatric brain tumors including JPA. However, the response of both tumors and normal tissues to PT is currently under investigation. We report tumor and normal brain tissue responses for a pediatric case of JPA treated withmore » PT assessed using DTI. Methods: A ten year old male with JPA of the left thalamus received passive scattered PT to a dose of 50.4 Gy (RBE) in 28 fractions. Post PT, the patient has been followed up in seven years. At each follow up, MRI imaging including DTI was performed to assess response. MR images were registered to the treatment planning CT and the GTV mapped onto each MRI. The GTV contour was then mirrored to the right side of brain through the patient’s middle line to represent normal brain tissue. ADC and FA were measured within the ROIs. Results: Proton therapy can completely spare contra lateral brain while the target volume received full prescribed dose. From a series of MRI ADC images before and after PT at different follow ups, the enhancement corresponding to GTV had nearly disappeared more than 2 years after PT. Both ADC and FA demonstrate that contralateral normal brain tissue were not affect by PT and the tumor volume reverted to normal ADC and FA values. Conclusion: DTI allowed quantitative evaluation of tumor and normal brain tissue responses to PT. Further study in a larger cohort is warranted.« less

Normal development of human brain white matter from infancy to early adulthood: a diffusion tensor imaging study.

PubMed

Uda, Satoshi; Matsui, Mie; Tanaka, Chiaki; Uematsu, Akiko; Miura, Kayoko; Kawana, Izumi; Noguchi, Kyo

2015-01-01

Diffusion tensor imaging (DTI), which measures the magnitude of anisotropy of water diffusion in white matter, has recently been used to visualize and quantify parameters of neural tracts connecting brain regions. In order to investigate the developmental changes and sex and hemispheric differences of neural fibers in normal white matter, we used DTI to examine 52 healthy humans ranging in age from 2 months to 25 years. We extracted the following tracts of interest (TOIs) using the region of interest method: the corpus callosum (CC), cingulum hippocampus (CGH), inferior longitudinal fasciculus (ILF), and superior longitudinal fasciculus (SLF). We measured fractional anisotropy (FA), apparent diffusion coefficient (ADC), axial diffusivity (AD), and radial diffusivity (RD). Approximate values and changes in growth rates of all DTI parameters at each age were calculated and analyzed using LOESS (locally weighted scatterplot smoothing). We found that for all TOIs, FA increased with age, whereas ADC, AD and RD values decreased with age. The turning point of growth rates was at approximately 6 years. FA in the CC was greater than that in the SLF, ILF and CGH. Moreover, FA, ADC and AD of the splenium of the CC (sCC) were greater than in the genu of the CC (gCC), whereas the RD of the sCC was lower than the RD of the gCC. The FA of right-hemisphere TOIs was significantly greater than that of left-hemisphere TOIs. In infants, growth rates of both FA and RD were larger than those of AD. Our data show that developmental patterns differ by TOIs and myelination along with the development of white matter, which can be mainly expressed as an increase in FA together with a decrease in RD. These findings clarify the long-term normal developmental characteristics of white matter microstructure from infancy to early adulthood. © 2015 S. Karger AG, Basel.

Flow cytometric characterization of the response of Fanconi's anemia cells to mitomycin C treatment.

PubMed

Kaiser, T N; Lojewski, A; Dougherty, C; Juergens, L; Sahar, E; Latt, S A

1982-03-01

DNA flow histogram analysis, using 33342 Hoechst as a stain, has been used to detect the effect of the potentially bifunctional alkylating agent, mitomycin C (MMC) on dermal fibroblasts from patients with Fanconi's anemia (FA), a hereditary human disease characterized by pancytopenia, hypersensitivity to DNA-crosslinking agents, congenital abnormalities and a predisposition for neoplasia. At 24 or 48 hr after a 2-hr exposure to 0.05 or 0.10 micrograms/ml MMC, (3)HdT incorporation was reduced to a greater extent in FA cells than in normal cells. Cells sorted from the last half of S phase showed a slightly greater inhibition of (3)HdT incorporation than did those sorted from the first half of S. Fanconi's anemia cells exhibited a marked accumulation in the G(2) + M peak of flow histograms following exposure to MMC. Twenty-four hr after treatment with .0.5 micrograms/ml MMC, the G(2) + M fraction of FA cells (eight lines) increased to more than 0.5 from a control value of approximately 0.02. Both normals (six lines) and heterozygotes (eight lines) showed, on the average, much less of a G(2) + M increment than did FA cells, even after exposure to 0.1 micrograms/ml MMC. Examination of cells sorted from the G(2) + M peak revealed that MMC-treated FA cells were blocked prior to mitosis. To determine whether the response of FA cells was specific for bifunctional alkylating agent, cells were also treated with ethylmethanesulfonate, a monofunctional agent. Twenty-four hours after exposure to 0.25 or 0.5 mg/ml ethylmethanesulfonate, FA and normal cells showed similar, small increases in the G(2) + M peak. The results suggest the utility of flow cytometry in the diagnostic evaluation of fibroblasts from patients suspected of having Fanconi's anemia.

Experience of diffusion tensor imaging and 1H spectroscopy for outcome prediction in severe traumatic brain injury: Preliminary results.

PubMed

Tollard, Eléonore; Galanaud, Damien; Perlbarg, Vincent; Sanchez-Pena, Paola; Le Fur, Yann; Abdennour, Lamine; Cozzone, Patrick; Lehericy, Stéphane; Chiras, Jacques; Puybasset, Louis

2009-04-01

The objective of the study is to test whether multimodal magnetic resonance imaging can provide a reliable outcome prediction of the clinical status, focusing on consciousness at 1 year after severe traumatic brain injury (TBI). Single center prospective cohort with consecutive inclusions. Critical Care Neurosurgical Unit of a university hospital. Forty-three TBI patients not responding to simple orders after sedation cessation and 15 healthy controls. A multimodal magnetic resonance imaging combining morphologic sequences, diffusion tensor imaging (DTI), and H proton magnetic resonance spectroscopy (MRS) was performed 24 +/- 11 days after severe TBI. The ability of DTI and MRS to predict 1-year outcome was assessed by linear discriminant analysis (LDA). Robustness of the classification was tested using a bootstrap procedure. Fractional anisotropy (FA) was computed as the mean of values at discrete brain sites in the infratentorial and supratentorial regions. The N-acetyl aspartate/creatine (NAA/Cr) ratio was measured in the thalamus, lenticular nucleus, insular cortex, occipital periventricular white matter, and pons. After 1 year, 19 (44%) patients had unfavorable outcomes (death, persistent vegetative state, or minimally conscious state) and 24 (56%) favorable outcomes (normal consciousness with or without functional impairments). Analysis of variance was performed to compare FA and NAA/Cr in the two outcome groups and controls. FA and MRS findings showed highly significant differences between the outcome groups, with significant variables by LDA being supratentorial FA, NAA/Cr (pons), NAA/Cr (thalamus), NAA/Cr (insula), and infratentorial FA. LDA of combined FA and MRS data clearly separated the unfavorable outcome, favorable outcome, and control groups, with no overlap. Unfavorable outcome was predicted with up to 86% sensitivity and 97% specificity; these values were better than those obtained with DTI or MRS alone. FA and NAA/Cr hold potential as quantitative outcome-prediction tools at the subacute phase of TBI.

White matter microstructural abnormalities in the frontal lobe of adults with antisocial personality disorder.

PubMed

Sundram, Frederick; Deeley, Quinton; Sarkar, Sagari; Daly, Eileen; Latham, Richard; Craig, Michael; Raczek, Malgorzata; Fahy, Tom; Picchioni, Marco; Barker, Gareth J; Murphy, Declan G M

2012-02-01

Antisocial personality disorder (ASPD) and psychopathy involve significant interpersonal and behavioural impairments. However, little is known about their underlying neurobiology and in particular, abnormalities in white matter (WM) microstructure. A preliminary diffusion tensor magnetic resonance imaging (DT-MRI) study of adult psychopaths employing tractography revealed abnormalities in the right uncinate fasciculus (UF) (Craig et al., 2009), indicating fronto-limbic disconnectivity. However, it is not clear whether WM abnormalities are restricted to this tract or are or more widespread, including other tracts which are involved in connectivity with the frontal lobe. We performed whole brain voxel-based analyses on WM fractional anisotropy (FA) and mean diffusivity (MD) maps acquired with DT-MRI to compare 15 adults with ASPD and healthy age, handedness and IQ-matched controls. Also, within ASPD subjects we related differences in FA and MD to measures of psychopathy. Significant WM FA reduction and MD increases were found respectively in ASPD subjects relative to controls. FA was bilaterally reduced in the genu of corpus callosum while in the right frontal lobe FA reduction was found in the UF, inferior fronto-occipital fasciculus (IFOF), anterior corona radiata and anterior limb and genu of the internal capsule. These differences negatively correlated with measures of psychopathy. Also in the right frontal lobe, increased MD was found in the IFOF and UF, and the corpus callosum and anterior corona radiata. There was a significant positive correlation between MD and psychopathy scores. The present study confirms a previous report of reduced FA in the UF. Additionally, we report for the first time, FA deficits in tracts involved in interhemispheric as well as frontal lobe connectivity in conjunction with MD increases in the frontal lobe. Hence, we provide evidence of significant WM microstructural abnormalities in frontal brain regions in ASPD and psychopathy. Copyright © 2011 Elsevier Srl. All rights reserved.

Microscopic diffusion anisotropy in the human brain: Age-related changes.

PubMed

Lawrenz, Marco; Brassen, Stefanie; Finsterbusch, Jürgen

2016-11-01

The fractional anisotropy (FA) that can be derived from diffusion tensor imaging (DTI), is ambiguous because it not only depends on the tissue microstructure but also on the axon or fiber orientation distribution within a voxel. Measures of the microscopic diffusion anisotropy, like the microscopic anisotropy index (MA) that can be determined with so-called double-wave-vector (DWV) or double diffusion encoding (DDE) imaging, are independent of this orientation distribution and, thus, offer a more direct and undisguised access to the tissue structure on a cellular or microscopic scale. In this study, FA and MA measurements were performed in a group of aged (>60y), healthy volunteers and compared to the data obtained recently for a group of young (<33y), healthy volunteers to reveal age-related differences. The coefficients-of-variation (CV) determined for the aged group were considerably lower for MA than for FA in average and in most of the 16 ROIs analyzed due to lower between-subject variations of MA. FA differences between the young and the aged group were in line with previous DTI studies. MA was also decreased in the aged group but in more of the 16 ROIs and with a higher significance. Furthermore, MA differences were also observed in frontal brain regions containing fiber crossings that did not reveal significant FA differences, i.e. MA seems to provide a better sensitivity to detect microstructural changes in such regions. In some non-cortical gray matter structures like the putamen, FA was increased but MA was decreased in the aged group which could indicate a coherent fiber orientation in the aged group related to the loss of crossing or fanning fibers. In conclusion, MA not only could improve the detectability of differences of the tissue microstructure but, in conjunction with FA, could also help to identify the underlying changes. Copyright © 2016 Elsevier Inc. All rights reserved.

The impact of CACNA1C gene, and its epistasis with ZNF804A, on white matter microstructure in health, schizophrenia and bipolar disorder1.

PubMed

Mallas, E; Carletti, F; Chaddock, C A; Shergill, S; Woolley, J; Picchioni, M M; McDonald, C; Toulopoulou, T; Kravariti, E; Kalidindi, S; Bramon, E; Murray, R; Barker, G J; Prata, D P

2017-04-01

Genome-wide studies have identified allele A (adenine) of single nucleotide polymorphism (SNP) rs1006737 of the calcium-channel CACNA1C gene as a risk factor for both schizophrenia (SZ) and bipolar disorder (BD) as well as allele A for rs1344706 in the ZNF804A gene. These illnesses have also been associated with white matter abnormalities, reflected by reductions in fractional anisotropy (FA), measured using diffusion tensor imaging (DTI). We assessed the impact of the CACNA1C psychosis risk variant on FA in SZ, BD and health. 230 individuals (with existing ZNF804A rs1344706 genotype data) were genotyped for CACNA1C rs1006737 and underwent DTI. FA data was analysed with tract-based spatial statistics and threshold-free cluster enhancement significance correction (P < 0.05) to detect effects of CACNA1C genotype on FA, and its potential interaction with ZNF804A genotype and with diagnosis, on FA. There was no significant main effect of the CACNA1C genotype on FA, nor diagnosis by genotype(s) interactions. Nevertheless, when inspecting SZ in particular, risk allele carriers had significantly lower FA than the protective genotype individuals, in portions of the left middle occipital and parahippocampal gyri, right cerebellum, left optic radiation and left inferior and superior temporal gyri. Our data suggests a minor involvement of CACNA1C rs1006737 in psychosis via conferring susceptibility to white matter microstructural abnormalities in SZ. Put in perspective, ZNF804A rs1344706, not only had a significant main effect, but its SZ-specific effects were two orders of magnitude more widespread than that of CACNA1C rs1006737. © 2016 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

Differences in Brain Morphological Findings between Narcolepsy with and without Cataplexy

PubMed Central

Nakamura, Masaki; Nishida, Shingo; Hayashida, Kenichi; Ueki, Yoichiro; Dauvilliers, Yves; Inoue, Yuichi

2013-01-01

Objective Maps of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) obtained by diffusion tensor imaging (DTI) can detect microscopic axonal changes by estimating the diffusivity of water molecules using magnetic resonance imaging (MRI). We applied an MRI voxel-based statistical approach to FA and ADC maps to evaluate microstructural abnormalities in the brain in narcolepsy and to investigate differences between patients having narcolepsy with and without cataplexy. Methods Twelve patients with drug-naive narcolepsy with cataplexy (NA/CA), 12 with drug-naive narcolepsy without cataplexy (NA w/o CA) and 12 age-matched healthy normal controls (NC) were enrolled. FA and ADC maps for these 3 groups were statistically compared by using voxel-based one-way ANOVA. In addition, we investigated the correlation between FA and ADC values and clinical variables in the patient groups. Results Compared to the NC group, the NA/CA group showed higher ADC values in the left inferior frontal gyrus and left amygdala, and a lower ADC value in the left postcentral gyrus. The ADC value in the right inferior frontal gyrus and FA value in the right precuneus were higher for NA/CA group than for the NA w/o CA group. However, no significant differences were observed in FA and ADC values between the NA w/o CA and NC groups in any of the areas investigated. In addition, no correlation was found between the clinical variables and ADC and FA values of any brain areas in these patient groups. Conclusions Several microstructural changes were noted in the inferior frontal gyrus and amygdala in the NA/CA but not in the NA w/o CA group. These findings suggest that these 2 narcolepsy conditions have different pathological mechanisms: narcolepsy without cataplexy form appears to be a potentially broader condition without any significant brain imaging differences from normal controls. PMID:24312261

Prediction of the wash-off of traffic related semi- and non-volatile organic compounds from urban roads under climate change influenced rainfall characteristics.

PubMed

Mahbub, Parvez; Goonetilleke, Ashantha; Ayoko, Godwin A

2012-04-30

Traffic generated semi- and non-volatile organic compounds (SVOCs and NVOCs) pose a serious threat to human and ecosystem health when washed off into receiving water bodies by stormwater. Climate change influenced rainfall characteristics makes the estimation of these pollutants in stormwater quite complex. The research study discussed in the paper developed a prediction framework for such pollutants under the dynamic influence of climate change on rainfall characteristics. It was established through principal component analysis (PCA) that the intensity and durations of low to moderate rain events induced by climate change mainly affect the wash-off of SVOCs and NVOCs from urban roads. The study outcomes were able to overcome the limitations of stringent laboratory preparation of calibration matrices by extracting uncorrelated underlying factors in the data matrices through systematic application of PCA and factor analysis (FA). Based on the initial findings from PCA and FA, the framework incorporated orthogonal rotatable central composite experimental design to set up calibration matrices and partial least square regression to identify significant variables in predicting the target SVOCs and NVOCs in four particulate fractions ranging from >300 to 1 μm and one dissolved fraction of <1 μm. For the particulate fractions in >300-1 μm range, similar distributions of predicted and observed concentrations of the target compounds from minimum to 75th percentile were achieved. The inter-event coefficient of variations for particulate fractions of >300-1 μm was 5-25%. The limited solubility of the target compounds in stormwater restricted the predictive capacity of the proposed method for the dissolved fraction of <1 μm. Copyright © 2012 Elsevier B.V. All rights reserved.

Unsaturated Lipids Change in Olive Tree Drupe and Seed during Fruit Development and in Response to Cold-Stress and Acclimation

PubMed Central

D’Angeli, Simone; Altamura, Maria Maddalena

2016-01-01

The olive tree is a plant of economic value for the oil of its drupe. It is a cultigen complex composed of genotypes with differences in cold-hardiness. About 90% of the oil is stored in oil bodies (OBs) in the drupe during the oleogenic phase. Phenols and lipids contribute to oil quality, but the unsaturated fatty acid (FA) fraction is emerging as the most important for quality, because of the very high content in oleic acid, the presence of ω6-linoleic acid and ω3-linolenic acid, and the very low saturated FA content. Another 10% of oil is produced by the seed. Differences in unsaturated FA-enriched lipids exist among seed coat, endosperm, and embryo. Olive oil quality is also affected by the environmental conditions during fruit growth and genotype peculiarities. Production of linoleic and α-linolenic acids, fruit growth, fruit and leaf responses to low temperatures, including cuticle formation, and cold-acclimation are related processes. The levels of unsaturated FAs are changed by FA-desaturase (FAD) activities, involving the functioning of chloroplasts and endoplasmic reticulum. Cold induces lipid changes during drupe and seed development, affecting FADs, but its effect is related to the genotype capability to acclimate to the cold. PMID:27845749

Evaluating multicenter DTI data in Huntington's disease on site specific effects: An ex post facto approach.

PubMed

Müller, Hans-Peter; Grön, Georg; Sprengelmeyer, Reiner; Kassubek, Jan; Ludolph, Albert C; Hobbs, Nicola; Cole, James; Roos, Raymund A C; Duerr, Alexandra; Tabrizi, Sarah J; Landwehrmeyer, G Bernhard; Süssmuth, Sigurd D

2013-01-01

Assessment of the feasibility to average diffusion tensor imaging (DTI) metrics of MRI data acquired in the course of a multicenter study. Sixty-one early stage Huntington's disease patients and forty healthy controls were studied using four different MR scanners at four European sites with acquisition protocols as close as possible to a given standard protocol. The potential and feasibility of averaging data acquired at different sites was evaluated quantitatively by region-of-interest (ROI) based statistical comparisons of coefficients of variation (CV) across centers, as well as by testing for significant group-by-center differences on averaged fractional anisotropy (FA) values between patients and controls. In addition, a whole-brain based statistical between-group comparison was performed using FA maps. The ex post facto statistical evaluation of CV and FA-values in a priori defined ROIs showed no differences between sites above chance indicating that data were not systematically biased by center specific factors. Averaging FA-maps from DTI data acquired at different study sites and different MR scanner types does not appear to be systematically biased. A suitable recipe for testing on the possibility to pool multicenter DTI data is provided to permit averaging of DTI-derived metrics to differentiate patients from healthy controls at a larger scale.

Contribution of microorganisms to non-extractable residue formation during biodegradation of ibuprofen in soil.

PubMed

Nowak, Karolina M; Girardi, Cristobal; Miltner, Anja; Gehre, Matthias; Schäffer, Andreas; Kästner, Matthias

2013-02-15

Non-extractable residues (NER) formed during biodegradation of organic contaminants in soil are considered to be mainly composed of parent compounds or their primary metabolites with hazardous potential. However, in the case of biodegradable organic compounds, the soil NER may also contain microbial biomass components, for example fatty acids (FA) and amino acids (AA). After cell death, these biomolecules are subsequently incorporated into non-living soil organic matter (SOM) and are stabilised ultimately forming hardly extractable residues of biogenic origin. We investigated biodegradation of (13)C(6)-ibuprofen, in particular the metabolic incorporation of the (13)C-label into FA and AA and their fate in soil over 90 days. (13)C-FA and (13)C-AA amounts in the living microbial biomass fraction initially increased, then decreased over time and were continuously incorporated into the non-living SOM pool. The (13)C-FA in the non-living SOM remained stable from day 59 whereas the contents of (13)C-AA slightly increased until the end. After 90 days, nearly all NER were biogenic as they were made up almost completely by natural biomass compounds. The presented data demonstrated that the potential environmental risks related to the ibuprofen-derived NER are overestimated. Copyright © 2012 Elsevier B.V. All rights reserved.

Differences in Cortical Representation and Structural Connectivity of Hands and Feet between Professional Handball Players and Ballet Dancers

PubMed Central

Meier, Jessica; Topka, Marlene Sofie; Hänggi, Jürgen

2016-01-01

It is known that intensive training and expertise are associated with functional and structural neuroadaptations. Most studies, however, compared experts with nonexperts; hence it is, specifically for sports, unclear whether the neuroplastic adaptations reported are sport-specific or sport-general. Here we aimed at investigating sport-specific adaptations in professional handball players and ballet dancers by focusing on the primary motor and somatosensory grey matter (GM) representation of hands and feet using voxel-based morphometry as well as on fractional anisotropy (FA) of the corticospinal tract by means of diffusion tensor imaging-based fibre tractography. As predicted, GM volume was increased in hand areas of handball players, whereas ballet dancers showed increased GM volume in foot areas. Compared to handball players, ballet dancers showed decreased FA in both fibres connecting the foot and hand areas, but they showed lower FA in fibres connecting the foot compared to their hand areas, whereas handball players showed lower FA in fibres connecting the hand compared to their foot areas. Our results suggest that structural adaptations are sport-specific and are manifested in brain regions associated with the neural processing of sport-specific skills. We believe this enriches the plasticity research in general and extends our knowledge of sport expertise in particular. PMID:27247805

Structural connections in the brain in relation to gender identity and sexual orientation.

PubMed

Burke, Sarah M; Manzouri, Amir H; Savic, Ivanka

2017-12-20

Both transgenderism and homosexuality are facets of human biology, believed to derive from different sexual differentiation of the brain. The two phenomena are, however, fundamentally unalike, despite an increased prevalence of homosexuality among transgender populations. Transgenderism is associated with strong feelings of incongruence between one's physical sex and experienced gender, not reported in homosexual persons. The present study searches to find neural correlates for the respective conditions, using fractional anisotropy (FA) as a measure of white matter connections that has consistently shown sex differences. We compared FA in 40 transgender men (female birth-assigned sex) and 27 transgender women (male birth-assigned sex), with both homosexual (29 male, 30 female) and heterosexual (40 male, 40 female) cisgender controls. Previously reported sex differences in FA were reproduced in cis-heterosexual groups, but were not found among the cis-homosexual groups. After controlling for sexual orientation, the transgender groups showed sex-typical FA-values. The only exception was the right inferior fronto-occipital tract, connecting parietal and frontal brain areas that mediate own body perception. Our findings suggest that the neuroanatomical signature of transgenderism is related to brain areas processing the perception of self and body ownership, whereas homosexuality seems to be associated with less cerebral sexual differentiation.

Brain white matter changes associated with urological chronic pelvic pain syndrome: multisite neuroimaging from a MAPP case-control study.

PubMed

Huang, Lejian; Kutch, Jason J; Ellingson, Benjamin M; Martucci, Katherine T; Harris, Richard E; Clauw, Daniel J; Mackey, Sean; Mayer, Emeran A; Schaeffer, Anthony J; Apkarian, A Vania; Farmer, Melissa A

2016-12-01

Clinical phenotyping of urological chronic pelvic pain syndromes (UCPPSs) in men and women have focused on end organ abnormalities to identify putative clinical subtypes. Initial evidence of abnormal brain function and structure in male pelvic pain has necessitated large-scale, multisite investigations into potential UCPPS brain biomarkers. We present the first evidence of regional white matter (axonal) abnormalities in men and women with UCPPS, compared with positive (irritable bowel syndrome, IBS) and healthy controls. Epidemiological and neuroimaging data were collected from participants with UCPPS (n = 52), IBS (n = 39), and healthy sex- and age-matched controls (n = 61). White matter microstructure, measured as fractional anisotropy (FA), was examined by diffusion tensor imaging. Group differences in regional FA positively correlated with pain severity, including segments of the right corticospinal tract and right anterior thalamic radiation. Increased corticospinal FA was specific and sensitive to UCPPS, positively correlated with pain severity, and reflected sensory (not affective) features of pain. Reduced anterior thalamic radiation FA distinguished patients with IBS from those with UCPPS and controls, suggesting greater microstructural divergence from normal tract organization. Findings confirm that regional white matter abnormalities characterize UCPPS and can distinguish between visceral diagnoses, suggesting that regional axonal microstructure is either altered with ongoing pain or predisposes its development.

Differential activation of Fyn kinase distinguishes saturated and unsaturated fats in mouse macrophages.

PubMed

Tarabra, Elena; An Lee, Ting-Wen; Zammit, Victor A; Vatish, Manu; Yamada, Eijiro; Pessin, Jeffrey E; Bastie, Claire C

2017-10-17

Diet-induced obesity is associated with increased adipose tissue activated macrophages. Yet, how macrophages integrate fatty acid (FA) signals remains unclear. We previously demonstrated that Fyn deficiency ( fynKO ) protects against high fat diet-induced adipose tissue macrophage accumulation. Herein, we show that inflammatory markers and reactive oxygen species are not induced in fynKO bone marrow-derived macrophages exposed to the saturated FA palmitate, suggesting that Fyn regulates macrophage function in response to FA signals. Palmitate activates Fyn and re-localizes Fyn into the nucleus of RAW264.7, J774 and wild-type bone marrow-derived macrophages. Similarly, Fyn activity is increased in cells of adipose tissue stromal vascular fraction of high fat-fed control mice, with Fyn protein being located in the nucleus of these cells. We demonstrate that Fyn modulates palmitate-dependent oxidative stress in macrophages. Moreover, Fyn catalytic activity is necessary for its nuclear re-localization and downstream effects, as Fyn pharmacological inhibition abolishes palmitate-induced Fyn nuclear redistribution and palmitate-dependent increase of oxidative stress markers. Importantly, mono-or polyunsaturated FAs do not activate Fyn, and fail to re-localize Fyn to the nucleus. Together these data demonstrate that macrophages integrate nutritional FA signals via a differential activation of Fyn that distinguishes, at least partly, the effects of saturated versus unsaturated fats.

Biological and cognitive correlates of cortical curvature in schizophrenia.

PubMed

Lubeiro, Alba; de Luis-García, Rodrigo; Rodríguez, Margarita; Álvarez, Aldara; de la Red, Henar; Molina, Vicente

2017-10-27

Mean cortical curvature may relate to cortico-cortical connections integrity. We explored the association between prefrontal (PFC) cortical curvature and fractional anisotropy (FA) values for tracts connecting PFC and relevant cortical regions. In schizophrenia Anatomical and diffusion magnetic resonance images were obtained from 34 patients (16 of them first-episodes) and 32 healthy controls. We calculated curvature at rostral lateral prefrontal (RLPF) and superior medial prefrontal (SMPF) areas and mean FA for the tracts respectively connecting RLPF and SMPF areas with anterior caudal cingulate (ACC), superior temporal gyrus (STG) and superior parietal SP regions. Cognitive and clinical data were collected, including baseline symptoms, Clinical Global Impression change scores from baseline to follow-up, illness duration and treatment dosage. Patients showed significantly lower FA values in the tracts linking right RLPF-ACC, right SMPF-SPG and bilaterally PFC-STG. FA values in short-range cortico-cortical connections (linking PFC and ACC) were inversely associated with PFC curvature. In patients, cognitive performance was negatively associated with PFC curvature. Larger curvature values were associated to lack of clinical improvement at follow-up. We conclude that cortical curvature is influenced by integrity in short-range cortico-cortical connections and relates to cognition and clinical outcome in schizophrenia patients. Copyright © 2017 Elsevier B.V. All rights reserved.

Subgenual Cingulum Microstructure Supports Control of Emotional Conflict.

PubMed

Keedwell, Paul A; Doidge, Amie N; Meyer, Marcel; Lawrence, Natalia; Lawrence, Andrew D; Jones, Derek K

2016-06-01

Major depressive disorder (MDD) is associated with specific difficulties in attentional disengagement from negatively valenced material. Diffusion MRI studies have demonstrated altered white matter microstructure in the subgenual cingulum bundle (CB) in individuals with MDD, though the functional significance of these alterations has not been examined formally. This study explored whether individual differences in selective attention to negatively valenced stimuli are related to interindividual differences in subgenual CB microstructure. Forty-six individuals (21 with remitted MDD, 25 never depressed) completed an emotional Stroop task, using happy and angry distractor faces overlaid by pleasant or unpleasant target words and a control gender-based Stroop task. CBs were reconstructed in 38 individuals using diffusion-weighted imaging and tractography, and mean fractional anisotropy (FA) computed for the subgenual, retrosplenial, and parahippocampal subdivisions. No significant correlations were found between FA and performance in the control gender-based Stroop task in any CB region. However, the degree of interference produced by angry face distractors on time to identify pleasant words (emotional conflict) correlated selectively with FA in the subgenual CB (r = -0.53; P = 0.01). Higher FA was associated with reduced interference, irrespective of a diagnosis of MDD, suggesting that subgenual CB microstructure is functionally relevant for regulating attentional bias toward negative interpersonal stimuli. © The Author 2016. Published by Oxford University Press.

A diffusion tensor imaging study of suicide attempters

PubMed Central

Thapa-Chhetry, Binod; Sublette, M. Elizabeth; Sullivan, Gregory M.; Oquendo, Maria A.; Mann, J. John; Parsey, Ramin V.

2014-01-01

Background Few studies have examined white matter abnormalities in suicide attempters using diffusion tensor imaging (DTI). This study sought to identify white matter regions altered in individuals with a prior suicide attempt. Methods DTI scans were acquired in 13 suicide attempters with major depressive disorder (MDD), 39 non-attempters with MDD, and 46 healthy participants (HP). Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) was determined in the brain using two methods: region of interest (ROI) and tract-based spatial statistics (TBSS). ROIs were limited a priori to white matter adjacent to the caudal anterior cingulate cortex, rostral anterior cingulate cortex, dorsomedial prefrontal cortex, and medial orbitofrontal cortex. Results Using the ROI approach, suicide attempters had lower FA than MDD non-attempters and HP in the dorsomedial prefrontal cortex. Uncorrected TBSS results confirmed a significant cluster within the right dorsomedial prefrontal cortex indicating lower FA in suicide attempters compared to non-attempters. There were no differences in ADC when comparing suicide attempters, non-attempters and HP groups using ROI or TBSS methods. Conclusions Low FA in the dorsomedial prefrontal cortex was associated with a suicide attempt history. Converging findings from other imaging modalities support this finding, making this region of potential interest in determining the diathesis for suicidal behavior. PMID:24462041

Independent component analysis of DTI data reveals white matter covariances in Alzheimer's disease

NASA Astrophysics Data System (ADS)

Ouyang, Xin; Sun, Xiaoyu; Guo, Ting; Sun, Qiaoyue; Chen, Kewei; Yao, Li; Wu, Xia; Guo, Xiaojuan

2014-03-01

Alzheimer's disease (AD) is a progressive neurodegenerative disease with the clinical symptom of the continuous deterioration of cognitive and memory functions. Multiple diffusion tensor imaging (DTI) indices such as fractional anisotropy (FA) and mean diffusivity (MD) can successfully explain the white matter damages in AD patients. However, most studies focused on the univariate measures (voxel-based analysis) to examine the differences between AD patients and normal controls (NCs). In this investigation, we applied a multivariate independent component analysis (ICA) to investigate the white matter covariances based on FA measurement from DTI data in 35 AD patients and 45 NCs from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. We found that six independent components (ICs) showed significant FA reductions in white matter covariances in AD compared with NC, including the genu and splenium of corpus callosum (IC-1 and IC-2), middle temporal gyral of temporal lobe (IC-3), sub-gyral of frontal lobe (IC-4 and IC-5) and sub-gyral of parietal lobe (IC-6). Our findings revealed covariant white matter loss in AD patients and suggest that the unsupervised data-driven ICA method is effective to explore the changes of FA in AD. This study assists us in understanding the mechanism of white matter covariant reductions in the development of AD.

Subgenual Cingulum Microstructure Supports Control of Emotional Conflict

PubMed Central

Keedwell, Paul A.; Doidge, Amie N.; Meyer, Marcel; Lawrence, Natalia; Lawrence, Andrew D.; Jones, Derek K.

2016-01-01

Major depressive disorder (MDD) is associated with specific difficulties in attentional disengagement from negatively valenced material. Diffusion MRI studies have demonstrated altered white matter microstructure in the subgenual cingulum bundle (CB) in individuals with MDD, though the functional significance of these alterations has not been examined formally. This study explored whether individual differences in selective attention to negatively valenced stimuli are related to interindividual differences in subgenual CB microstructure. Forty-six individuals (21 with remitted MDD, 25 never depressed) completed an emotional Stroop task, using happy and angry distractor faces overlaid by pleasant or unpleasant target words and a control gender-based Stroop task. CBs were reconstructed in 38 individuals using diffusion-weighted imaging and tractography, and mean fractional anisotropy (FA) computed for the subgenual, retrosplenial, and parahippocampal subdivisions. No significant correlations were found between FA and performance in the control gender-based Stroop task in any CB region. However, the degree of interference produced by angry face distractors on time to identify pleasant words (emotional conflict) correlated selectively with FA in the subgenual CB (r = −0.53; P = 0.01). Higher FA was associated with reduced interference, irrespective of a diagnosis of MDD, suggesting that subgenual CB microstructure is functionally relevant for regulating attentional bias toward negative interpersonal stimuli. PMID:27048427

Sex differences in adolescent white matter architecture.

PubMed

Bava, Sunita; Boucquey, Veronique; Goldenberg, Diane; Thayer, Rachel E; Ward, Megan; Jacobus, Joanna; Tapert, Susan F

2011-02-23

Sex-specific trajectories in white matter development during adolescence may help explain cognitive and behavioral divergences between males and females. Knowledge of sex differences in typically developing adolescents can provide a basis for interpreting sexual dimorphisms in abilities and actions. We examined 58 healthy adolescents (12-14years of age) with diffusion tensor imaging (DTI). Diffusion parameters fractional anisotropy (FA), and mean (MD), radial (RD), and axial diffusivities (AD) were subjected to whole-brain voxel-wise group comparisons using tract-based spatial statistics. Sex differences in white matter microstructure were examined in relation to pubertal development. Early adolescent females (n=29) evidenced higher FA in the right superior corona radiata, higher FA and AD in bilateral corticospinal tracts (≥164μl, p<.01), and lower MD in the right inferior longitudinal fasciculus (ILF) and left forceps major (≥164μl, p<.01) than age-matched males (n=29). Males did not show any areas of higher FA or lower MD than females, but had higher AD in the right superior longitudinal fasciculus, ILF, and forceps minor (≥ 164μl, p<.01). Pubertal stage did not account for sex disparities. In early adolescence, females' motor tracts may reflect widespread changes, while males may undergo relatively more microstructural change in projection and association fibers. Copyright © 2010 Elsevier B.V. All rights reserved.

Differences in Cortical Representation and Structural Connectivity of Hands and Feet between Professional Handball Players and Ballet Dancers.

PubMed

Meier, Jessica; Topka, Marlene Sofie; Hänggi, Jürgen

2016-01-01

It is known that intensive training and expertise are associated with functional and structural neuroadaptations. Most studies, however, compared experts with nonexperts; hence it is, specifically for sports, unclear whether the neuroplastic adaptations reported are sport-specific or sport-general. Here we aimed at investigating sport-specific adaptations in professional handball players and ballet dancers by focusing on the primary motor and somatosensory grey matter (GM) representation of hands and feet using voxel-based morphometry as well as on fractional anisotropy (FA) of the corticospinal tract by means of diffusion tensor imaging-based fibre tractography. As predicted, GM volume was increased in hand areas of handball players, whereas ballet dancers showed increased GM volume in foot areas. Compared to handball players, ballet dancers showed decreased FA in both fibres connecting the foot and hand areas, but they showed lower FA in fibres connecting the foot compared to their hand areas, whereas handball players showed lower FA in fibres connecting the hand compared to their foot areas. Our results suggest that structural adaptations are sport-specific and are manifested in brain regions associated with the neural processing of sport-specific skills. We believe this enriches the plasticity research in general and extends our knowledge of sport expertise in particular.

Sensitive period for white-matter connectivity of superior temporal cortex in deaf people.

PubMed

Li, Yanyan; Ding, Guosheng; Booth, James R; Huang, Ruiwang; Lv, Yating; Zang, Yufeng; He, Yong; Peng, Danling

2012-02-01

Previous studies have shown that white matter in the deaf brain changes due to hearing loss. However, how white-matter development is influenced by early hearing experience of deaf people is still unknown. Using diffusion tensor imaging and tract-based spatial statistics, we compared white-matter structures among three groups of subjects including 60 congenitally deaf individuals, 36 acquired deaf (AD) individuals, and 38 sex- and age-matched hearing controls (HC). The result showed that the deaf individuals had significantly reduced fractional anisotropy (FA) values in bilateral superior temporal cortex and the splenium of corpus callosum compared to HC. The reduction of FA values in acquired deafness correlated with onset age of deafness, but not the duration of deafness. To explore the underlying mechanism of FA changes in the deaf groups, we further analyzed radial and axial diffusivities and found that (1) the reduced FA values in deaf individuals compared to HC is primarily driven by higher radial diffusivity values and (2) in the AD, higher radial diffusivity was correlated with earlier onset age of deafness, but not the duration of deafness. These findings imply that early sensory experience is critical for the growth of fiber myelination, and anatomical reorganization following auditory deprivation is sensitive to early plasticity in the brain. Copyright © 2010 Wiley Periodicals, Inc.

Brain white matter changes associated with urological chronic pelvic pain syndrome: Multi-site neuroimaging from a MAPP case-control study

PubMed Central

Huang, Lejian; Kutch, Jason J.; Ellingson, Benjamin M.; Martucci, Katherine T.; Harris, Richard E.; Clauw, Daniel J.; Mackey, Sean; Mayer, Emeran A.; Schaeffer, Anthony J.; Apkarian, A. Vania; Farmer, Melissa A.

2016-01-01

Clinical phenotyping of urological chronic pelvic pain syndromes (UCPPS) in men and women has focused on end-organ abnormalities to identify putative clinical subtypes. Initial evidence of abnormal brain function and structure in male pelvic pain has necessitated large-scale, multi-site investigations into potential UCPPS brain biomarkers. We present the first evidence of regional white matter (axonal) abnormalities in men and women with UCPPS, compared to positive (irritable bowel syndrome, IBS) and healthy controls. Epidemiological and neuroimaging data was collected from participants with UCPPS (n=52), IBS (n=39), and healthy, sex- and age-matched controls (n=61). White matter microstructure, measured as fractional anisotropy (FA), was examined with diffusion tensor imaging (DTI). Group differences in regional FA positively correlated with pain severity, including segments of the right corticospinal tract and right anterior thalamic radiation. Increased corticospinal FA was specific and sensitive to UCPPS, positively correlated with pain severity, and reflected sensory (not affective) features of pain. Reduced anterior thalamic radiation FA distinguished IBS from UCPPS patients and controls, suggesting greater microstructural divergence from normal tract organization. Findings confirm that regional white matter abnormalities characterize UCPPS and can distinguish between visceral diagnoses, suggesting that regional axonal microstructure is either altered with ongoing pain or predisposes its development. PMID:27842046

A Fatty Acid Based Bayesian Approach for Inferring Diet in Aquatic Consumers

PubMed Central

Holtgrieve, Gordon W.; Ward, Eric J.; Ballantyne, Ashley P.; Burns, Carolyn W.; Kainz, Martin J.; Müller-Navarra, Doerthe C.; Persson, Jonas; Ravet, Joseph L.; Strandberg, Ursula; Taipale, Sami J.; Alhgren, Gunnel

2015-01-01

We modified the stable isotope mixing model MixSIR to infer primary producer contributions to consumer diets based on their fatty acid composition. To parameterize the algorithm, we generated a ‘consumer-resource library’ of FA signatures of Daphnia fed different algal diets, using 34 feeding trials representing diverse phytoplankton lineages. This library corresponds to the resource or producer file in classic Bayesian mixing models such as MixSIR or SIAR. Because this library is based on the FA profiles of zooplankton consuming known diets, and not the FA profiles of algae directly, trophic modification of consumer lipids is directly accounted for. To test the model, we simulated hypothetical Daphnia comprised of 80% diatoms, 10% green algae, and 10% cryptophytes and compared the FA signatures of these known pseudo-mixtures to outputs generated by the mixing model. The algorithm inferred these simulated consumers were comprised of 82% (63-92%) [median (2.5th to 97.5th percentile credible interval)] diatoms, 11% (4-22%) green algae, and 6% (0-25%) cryptophytes. We used the same model with published phytoplankton stable isotope (SI) data for δ13C and δ15N to examine how a SI based approach resolved a similar scenario. With SI, the algorithm inferred that the simulated consumer assimilated 52% (4-91%) diatoms, 23% (1-78%) green algae, and 18% (1-73%) cyanobacteria. The accuracy and precision of SI based estimates was extremely sensitive to both resource and consumer uncertainty, as well as the trophic fractionation assumption. These results indicate that when using only two tracers with substantial uncertainty for the putative resources, as is often the case in this class of analyses, the underdetermined constraint in consumer-resource SI analyses may be intractable. The FA based approach alleviated the underdetermined constraint because many more FA biomarkers were utilized (n < 20), different primary producers (e.g., diatoms, green algae, and cryptophytes) have very characteristic FA compositions, and the FA profiles of many aquatic primary consumers are strongly influenced by their diets. PMID:26114945

Role of the combination of FA and T2* parameters as a new diagnostic method in therapeutic evaluation of parkinson's disease.

PubMed

Fang, Yuan; Zheng, Tao; Liu, Lanxiang; Gao, Dawei; Shi, Qinglei; Dong, Yanchao; Du, Dan

2017-11-17

Simple diffusion delivery (SDD) has attained good effects with only tiny amounts of drugs. Fractional anisotropy (FA) and relaxation time T2* that indicate the integrity of fiber tracts and iron concentration within brain tissue were used to evaluate the therapeutic effect of SDD. To evaluate therapeutic effect of SDD in the Parkinson's disease (PD) rat model with FA and T2* parameters. Prospective case-control animal study. Thirty-two male Sprague Dawley rats (eight normal, eight PD, eight SDD, and eight subcutaneous injection rats). Single-shot spin echo echo-planar imaging and fast low-angle shot T 2 WI sequences at 3.0T. Parameters of FA and T2* on the treated side of the substantia nigra were measured to evaluate the therapeutic effect of SDD in a PD rat model. The effects of time on FA and T2* values were analyzed by repeated measurement tests. A one-way analysis of variance was conducted, followed by individual comparisons of the mean FA and T2* values at different timepoints. The FA values on the treated side of the substantia nigra in the SDD treatment group and subcutaneous injection treatment group were significantly higher at week 1 and lower at week 6 than that of the PD control group (SDD vs. PD, week 1, adjusted P = 0.012; subcutaneous vs. PD, week 1, adjusted P < 0.001; SDD vs. PD, week 6, adjusted P = 0.004; subcutaneous vs. PD, week 6, adjusted P = 0.024). The T2* parameter in the SDD treatment group and subcutaneous injection treatment group was significantly higher than that in the PD control group at week 6 (SDD vs. PD, adjusted P = 0.032; subcutaneous vs. PD, adjusted P < 0.001). The combination of FA and T2* parameters can potentially serve as a new effective evaluation method of the therapeutic effect of SDD. 1 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2017. © 2017 International Society for Magnetic Resonance in Medicine.

The DCDC2/intron 2 deletion and white matter disorganization: focus on developmental dyslexia.

PubMed

Marino, Cecilia; Scifo, Paola; Della Rosa, Pasquale A; Mascheretti, Sara; Facoetti, Andrea; Lorusso, Maria L; Giorda, Roberto; Consonni, Monica; Falini, Andrea; Molteni, Massimo; Gruen, Jeffrey R; Perani, Daniela

2014-08-01

The DCDC2 gene is involved in neuronal migration. Heterotopias have been found within the white matter of DCDC2-knockdown rats. A deletion in DCDC2/intron 2 (DCDC2d), which encompasses a regulatory region named 'regulatory element associated with dyslexia 1' (READ1), increases the risk for dyslexia. We hypothesized that DCDC2d can be associated to alterations of the white matter structure in general and in dyslexic brains. Based on a full-factorial analysis of covariance (ANCOVA) model, we investigated voxel-based diffusion tensor imaging (VB-DTI) data of four groups of subjects: dyslexia with/without DCDC2d, and normal readers with/without DCDC2d. We also tested DCDC2d effects upon correlation patterns between fractional anisotropy (FA) and reading scores. We found that FA was reduced in the left arcuate fasciculus and splenium of the corpus callosum in subjects with versus without DCDC2d, irrespective of dyslexia. Subjects with dyslexia and DCDC2d showed reduced FA, mainly in the left hemisphere and in the corpus callosum; their counterpart without DCDC2d showed similar FA alterations. Noteworthy, a conjunction analysis in impaired readers revealed common regions with lower FA mainly in the left hemisphere. When we compared subjects with dyslexia with versus without DCDC2d, we found lower FA in the inferior longitudinal fasciculus and genu of the corpus callosum, bilaterally. Normal readers with versus without DCDC2d had FA increases and decreases in both the right and left hemisphere. The major contribution of our study was to provide evidence relating genes, brain and behaviour. Overall, our findings support the hypothesis that DCDC2d is associated with altered FA. In normal readers, DCDC2-related anatomical patterns may mark some developmental cognitive vulnerability to learning disabilities. In subjects with dyslexia, DCDC2d accounted for both common - mainly located in the left hemisphere - and unique - a more severe and extended pattern - alterations of white matter fibre tracts. Copyright © 2014 Elsevier Ltd. All rights reserved.

Comparison of separations of fatty acids from fish products using a 30-m Supelcowax-10 and a 100-m SP-2560 column.

PubMed

Santercole, Viviana; Delmonte, Pierluigi; Kramer, John K G

2012-03-01

Commercial fish oils and foods containing fish may contain trans and/or isomerized fatty acids (FA) produced during processing or as part of prepared foods. The current American Oil Chemists' Society (AOCS) official method for marine oils (method Ce 1i-07) is based on separation by use of poly(ethylene glycol) (PEG) columns, for example Supelcowax-10 or equivalent, which do not resolve most unsaturated FA geometric isomers. Highly polar 100-m cyanopropyl siloxane (CPS) columns, for example SP-2560 and CP Sil 88 are recommended for separation of geometric FA isomers. Complementary separations were achieved by use of two different elution temperature programs with the same CPS column. This study is the first direct comparison of the separations achieved by use of 30-m Supelcowax-10 and 100-m SP-2560 columns for fatty acid methyl esters (FAME) prepared from the same fish oil and fish muscle sample. To simplify the identification of the FA in these fish samples, FA were fractionated on the basis of the number and type of double bonds by silver-ion solid-phase extraction (Ag⁺-SPE) before GC analysis. The results showed that a combination of the three GC separations was necessary to resolve and identify most of the unsaturated FA, FA isomers, and other components of fish products, for example phytanic and phytenic acids. Equivalent chain length (ECL) values of most FAME in fish were calculated from the separations achieved by use of both GC columns; the values obtained were shown to be consistent with previously reported values for the Supelcowax-10 column. ECL values were also calculated for the FA separated on the SP-2560 column. The calculated ECL values were equally valid under isothermal and temperature-programmed elution GC conditions, and were valuable for confirmation of the identity of several unsaturated FAME in the fish samples. When analyzing commercially prepared fish foods, deodorized marine oils, or foods fortified with marine oils it is strongly recommended that quantitative data acquired by use of PEG columns is complemented with data obtained from separations using highly polar CPS columns.

Heat and Mass Transfer of Ammonia Gas Absorption into Falling Liquid Film on a Horizontal Tube

NASA Astrophysics Data System (ADS)

Inoue, Norihiro; Yabuuchi, Hironori; Goto, Masao; Koyama, Shigeru

Heat and mass transfer coefficients during ammonia gas absorption into a falling liquid film formed by distilled water on a horizontal tube were obtained experimentally. The test absorber consists of 200 mm i.d., 600 mm long stainless steel shell, a 1 7.3 mm o.d., 14.9 mm i.d. stainless steel test tube with 600 mm working length mounted along the axis of shell, and a 12.7 mm o.d. pipe manifold of supplying the absorbent. In this paper, it was clear that heat and mass transfer coefficient could be enhanced by increasing the flow rate of absorbent and temperature difference between inlet absorbent and ammonia gas, also heat driven by the temperature difference have an effect on heat transfer of the fa1ling liquid film and mass transfer of vapor side. And the new correlation of heat transfer in dimensionless form was proposed by the temperature difference which was considered heat driven of vapor and liquid film side using a interface temperature of vapor and liquid phase. The new correlations of mass transfer on a interface of vapor and liquid phase in dimensionless form were proposed by using effect factors could be suppose from absorption phenomena.

Using joint ICA to link function and structure using MEG and DTI in schizophrenia

PubMed Central

Stephen, JM; Coffman, BA; Jung, RE; Bustillo, JR; Aine, CJ; Calhoun, VD

2013-01-01

In this study we employed joint independent component analysis (jICA) to perform a novel multivariate integration of magnetoencephalography (MEG) and diffusion tensor imaging (DTI) data to investigate the link between function and structure. This model-free approach allows one to identify covariation across modalities with different temporal and spatial scales [temporal variation in MEG and spatial variation in fractional anisotropy (FA) maps]. Healthy controls (HC) and patients with schizophrenia (SP) participated in an auditory/visual multisensory integration paradigm to probe cortical connectivity in schizophrenia. To allow direct comparisons across participants and groups, the MEG data were registered to an average head position and regional waveforms were obtained by calculating the local field power of the planar gradiometers. Diffusion tensor images obtained in the same individuals were preprocessed to provide FA maps for each participant. The MEG/FA data were then integrated using the jICA software (http://mialab.mrn.org/software/fit). We identified MEG/FA components that demonstrated significantly different (p < 0.05) covariation in MEG/FA data between diagnostic groups (SP vs. HC) and three components that captured the predominant sensory responses in the MEG data. Lower FA values in bilateral posterior parietal regions, which include anterior/posterior association tracts, were associated with reduced MEG amplitude (120-170 ms) of the visual response in occipital sensors in SP relative to HC. Additionally, increased FA in a right medial frontal region was linked with larger amplitude late MEG activity (300-400 ms) in bilateral central channels for SP relative to HC. Step-wise linear regression provided evidence that right temporal, occipital and late central components were significant predictors of reaction time and cognitive performance based on the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) cognitive assessment battery. These results point to dysfunction in a posterior visual processing network in schizophrenia, with reduced MEG amplitude, reduced FA and poorer overall performance on the MATRICS. Interestingly, the spatial location of the MEG activity and the associated FA regions are spatially consistent with white matter regions that subserve these brain areas. This novel approach provides evidence for significant pairing between function (electrophysiology) and structure (white matter integrity) and demonstrates the sensitivity of this multivariate, multimodal integration technique to group differences in function and structure. PMID:23777757

Assessment of a field-aligned ICRF antenna

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wukitch, S. J.; Brunner, D.; Ennever, P.

Impurity contamination and localized heat loads associated with ion cyclotron range of frequency (ICRF) antenna operation are among the most challenging issues for ICRF utilization.. Another challenge is maintaining maximum coupled power through plasma variations including edge localized modes (ELMs) and confinement transitions. Here, we report on an experimental assessment of a field aligned (FA) antenna with respect to impurity contamination, impurity sources, RF enhanced heat flux and load tolerance. In addition, we compare the modification of the scrape of layer (SOL) plasma potential of the FA antenna to a conventional, toroidally aligned (TA) antenna, in order to explore themore » underlying physics governing impurity contamination linked to ICRF heating. The FA antenna is a 4-strap ICRF antenna where the current straps and antenna enclosure sides are perpendicular to and the Faraday screen rods are parallel to the total magnetic field. In principle, alignment with respect to the total magnetic field minimizes integrated E∥ (electric field along a magnetic field line) via symmetry. Consistent with expectations, we observed that the impurity contamination and impurity source at the FA antenna are reduced compared to the TA antenna. In both L and H-mode discharges, the radiated power is 20–30% lower for a FA-antenna heated discharge than a discharge heated with the TA-antennas. Further we observe that the fraction of RF energy deposited upon the antenna is less than 0.4 % of the total injected RF energy in dipole phasing. The total deposited energy increases significantly when the FA antenna is operated in monopole phasing. The FA antenna also exhibits an unexpected load tolerance for ELMs and confinement transitions compared to the TA antennas. However, inconsistent with expectations, we observe RF induced plasma potentials to be nearly identical for FA and TA antennas when operated in dipole phasing. In monopole phasing, the FA antenna has the highest plasma potentials and poor heating efficiency despite calculations indicating low integrated E∥. In mode conversion heating scenario, no core waves were detected in the plasma core indicating poor wave penetration. For monopole phasing, simulations suggest the antenna spectrum is peaked at very short wavelength and full wave simulations show the short wavelength has poor wave penetration to the plasma core.« less

Analysis of non-esterified fatty acids in human samples by solid-phase-extraction and gas chromatography/mass spectrometry.

PubMed

Kopf, Thomas; Schmitz, Gerd

2013-11-01

The determination of the fatty acid (FA) profile of lipid classes is essential for lipidomic analysis. We recently developed a GC/MS-method for the analysis of the FA profile of total FAs, i.e. the totality of bound and unbound FAs, in any given biological sample (TOFAs). Here, we present a method for the analysis of non-esterified fatty acids (NEFAs) in biological samples, i.e. the fraction that is present as extractable free fatty acids. Lipid extraction is performed according to Dole using 80/20 2-propanol/n-hexane (v/v), with 0.1% H2SO4. The fatty acid-species composition of this NEFA-fraction is determined as FAME after derivatization with our GC/MS-method on a BPX column (Shimadzu). Validation of the NEFA-method presented was performed in human plasma samples. The validated method has been used with human plasma, cells and tissues, as well as mammalian body fluids and tissue samples. The newly developed solid-phase-extraction (SPE)-GC-MS method allows the rapid separation of the NEFA-fraction from a neutral lipid extract of plasma samples. As a major advantage compared to G-FID-methods, GC-MS allows the use of stable isotope labeled fatty acid precursors to monitor fatty acid metabolism. Copyright © 2013 Elsevier B.V. All rights reserved.

Induction of plasminogen activator inhibitor type-1 (PAI-1) by hypoxia and irradiation in human head and neck carcinoma cell lines

PubMed Central

Schilling, Daniela; Bayer, Christine; Geurts-Moespot, Anneke; Sweep, Fred CGJ; Pruschy, Martin; Mengele, Karin; Sprague, Lisa D; Molls, Michael

2007-01-01

Background Squamous cell carcinoma of the head and neck (SCCHN) often contain highly radioresistant hypoxic regions, nonetheless, radiotherapy is a common treatment modality for these tumours. Reoxygenation during fractionated radiotherapy is desired to render these hypoxic tumour regions more radiosensitive. Hypoxia additionally leads to up-regulation of PAI-1, a protein involved in tumour progression and an established prognostic marker for poor outcome. However, the impact of reoxygenation and radiation on PAI-1 levels is not yet clear. Therefore, we investigated the kinetics of PAI-1 expression and secretion after hypoxia and reoxygenation, and determined the influence of ionizing radiation on PAI-1 levels in the two human SCCHN cell lines, BHY and FaDu. Methods HIF-1α immunoblot was used to visualize the degree of hypoxia in the two cell lines. Cellular PAI-1 expression was investigated by immunofluorescence microscopy. ELISA was used to quantify relative changes in PAI-1 expression (cell lysates) and secretion (cell culture supernatants) in response to various lengths (2 – 4 h) of hypoxic exposure (< 0.66 % O2), reoxygenation (24 h, 20 % O2), and radiation (0, 2, 5 and 10 Gy). Results HIF-1α expression was induced between 2 and 24 h of hypoxic exposure. Intracellular PAI-1 expression was significantly increased in BHY and FaDu cells as early as 4 h after hypoxic exposure. A significant induction in secreted PAI-1 was seen after 12 to 24 h (BHY) and 8 to 24 h (FaDu) hypoxia, as compared to the normoxic control. A 24 h reoxygenation period caused significantly less PAI-1 secretion than a 24 h hypoxia period in FaDu cells. Irradiation led to an up-regulation of PAI-1 expression and secretion in both, BHY and FaDu cells. Conclusion Our data suggest that both, short-term (~4 – 8 h) and long-term (~20 – 24 h) hypoxic exposure could increase PAI-1 levels in SCCHN in vivo. Importantly, radiation itself could lead to PAI-1 up-regulation in head and neck tumours, whereas reoxygenation of hypoxic tumour cells during fractionated radiotherapy could counteract the increased PAI-1 levels. PMID:17663760

White Matter Microstructure of the Human Mirror Neuron System Is Related to Symptom Severity in Adults with Autism

ERIC Educational Resources Information Center

Fründt, Odette; Schulz, Robert; Schöttle, Daniel; Cheng, Bastian; Thomalla, Götz; Braaß, Hanna; Ganos, Christos; David, Nicole; Peiker, Ina; Engel, Andreas K.; Bäumer, Tobias; Münchau, Alexander

2018-01-01

Mirror neuron system (MNS) dysfunctions might underlie deficits in autism spectrum disorders (ASD). Diffusion tensor imaging based probabilistic tractography was conducted in 15 adult ASD patients and 13 matched, healthy controls. Fractional anisotropy (FA) was quantified to assess group differences in tract-related white matter microstructure of…

Shared genetic variance between obesity and white matter integrity in Mexican Americans.

PubMed

Spieker, Elena A; Kochunov, Peter; Rowland, Laura M; Sprooten, Emma; Winkler, Anderson M; Olvera, Rene L; Almasy, Laura; Duggirala, Ravi; Fox, Peter T; Blangero, John; Glahn, David C; Curran, Joanne E

2015-01-01

Obesity is a chronic metabolic disorder that may also lead to reduced white matter integrity, potentially due to shared genetic risk factors. Genetic correlation analyses were conducted in a large cohort of Mexican American families in San Antonio (N = 761, 58% females, ages 18-81 years; 41.3 ± 14.5) from the Genetics of Brain Structure and Function Study. Shared genetic variance was calculated between measures of adiposity [(body mass index (BMI; kg/m(2)) and waist circumference (WC; in)] and whole-brain and regional measurements of cerebral white matter integrity (fractional anisotropy). Whole-brain average and regional fractional anisotropy values for 10 major white matter tracts were calculated from high angular resolution diffusion tensor imaging data (DTI; 1.7 × 1.7 × 3 mm; 55 directions). Additive genetic factors explained intersubject variance in BMI (heritability, h (2) = 0.58), WC (h (2) = 0.57), and FA (h (2) = 0.49). FA shared significant portions of genetic variance with BMI in the genu (ρG = -0.25), body (ρG = -0.30), and splenium (ρG = -0.26) of the corpus callosum, internal capsule (ρG = -0.29), and thalamic radiation (ρG = -0.31) (all p's = 0.043). The strongest evidence of shared variance was between BMI/WC and FA in the superior fronto-occipital fasciculus (ρG = -0.39, p = 0.020; ρG = -0.39, p = 0.030), which highlights region-specific variation in neural correlates of obesity. This may suggest that increase in obesity and reduced white matter integrity share common genetic risk factors.

White matter microstructure in athletes with a history of concussion: Comparing diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI).

PubMed

Churchill, Nathan W; Caverzasi, Eduardo; Graham, Simon J; Hutchison, Michael G; Schweizer, Tom A

2017-08-01

Sport concussion is associated with disturbances in brain function in the absence of gross anatomical lesions, and may have long-term health consequences. Diffusion-weighted magnetic resonance imaging (MRI) methods provide a powerful tool for investigating alterations in white matter microstructure reflecting the long-term effects of concussion. In a previous study, diffusion tensor imaging (DTI) showed that athletes with a history of concussion had elevated fractional anisotropy (FA) and reduced mean diffusivity (MD) parameters. To better understand these effects, this study compared DTI results to neurite orientation dispersion and density imaging (NODDI), which was used to estimate the intracellular volume fraction (V IC ) and orientation dispersion index (ODI). Sixty-eight (68) varsity athletes were recruited, including 37 without a history of concussion and 31 with concussion >6 months prior to imaging. Univariate analyses showed elevated FA and decreased MD for concussed athletes, along with increased V IC and reduced ODI, indicating greater neurite density and coherence of neurite orientation within white matter. Multivariate analyses also showed that for athletes with a history of concussion, white matter regions with increased FA had increased V IC and decreased ODI, with greater effects among athletes who were imaged a longer time since their last concussion. These findings enhance our understanding of the relationship between the biophysics of water diffusion and concussion neurobiology for young, healthy adults. Hum Brain Mapp 38:4201-4211, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Translocation of a heterogeneous polymer

PubMed Central

Mirigian, Stephen; Wang, Yanbo; Muthukumar, Murugappan

2012-01-01

We present results on the sequence dependence of translocation kinetics for a partially charged heteropolymer moving through a very thin pore using theoretical tools and Langevin dynamics simulational techniques. The chain is composed of two types of monomers of differing frictional interaction with the pore and charge. We present exact analytical expressions for passage probability, mean first passage time, and mean successful passage times for both reflecting/absorbing and absorbing/absorbing boundary conditions, showing rich and unexpected dependence of translocation behavior on charge fraction, distribution along the chain, and electric field configuration. We find excellent qualitative and good quantitative agreement between theoretical and simulation results. Surprisingly, there emerges a threshold charge fraction of a diblock copolymer beyond which the success rate of translocation is independent of charge fraction. Also, the mean successful translocation time of a diblock copolymer displays non-monotonic behavior with increasing length of the charged block; there is an optimum length of the charged block where the mean translocation rate is the slowest; and there can be a substantial range of higher charge fractions which make the translocation slower than even a minimally charged chain. Additionally, we find for a fixed total charge on the chain, finer distribution along the backbone significantly decreases mean translocation time. PMID:22897308

A Solar Volumetric Receiver: Influence of Absorbing Cells Configuration on Device Thermal Performance

NASA Astrophysics Data System (ADS)

Yilbas, B. S.; Shuja, S. Z.

2017-01-01

Thermal performance of a solar volumetric receiver incorporating the different cell geometric configurations is investigated. Triangular, hexagonal, and rectangular absorbing cells are incorporated in the analysis. The fluid volume fraction, which is the ratio of the volume of the working fluid over the total volume of solar volumetric receiver, is introduced to assess the effect of cell size on the heat transfer rates in the receiver. In this case, reducing the fluid volume fraction corresponds to increasing cell size in the receiver. SiC is considered as the cell material, and air is used as the working fluid in the receiver. The Lambert's Beer law is incorporated to account for the solar absorption in the receiver. A finite element method is used to solve the governing equation of flow and heat transfer. It is found that the fluid volume fraction has significant effect on the flow field in the solar volumetric receiver, which also modifies thermal field in the working fluid. The triangular absorbing cell gives rise to improved effectiveness of the receiver and then follows the hexagonal and rectangular cells. The second law efficiency of the receiver remains high when hexagonal cells are used. This occurs for the fluid volume fraction ratio of 0.5.

The reactivity of natural organic matter to disinfection by-products formation and its relation to specific ultraviolet absorbance.

PubMed

Kitis, M; Karanfil, T; Kilduff, J E; Wigton, A

2001-01-01

Five natural waters with a broad range of DOC concentrations were fractionated using various coal- and wood-based granular activated carbons (GAC) and alum coagulation. Adsorption and alum coagulation fractionated NOM solutions by preferentially removing components having high specific ultraviolet absorbance (SUVA). UV absorbing fractions of NOM were found to be the major contributors to DBP formation. SUVA appears to be an accurate predictor of reactivity with chlorine in terms of DBP yield; however, it was also found that low-SUVA components of NOM have higher bromine incorporation. SUVA has promise as a parameter for on-line monitoring and control of DBP formation in practical applications; however, the effects of bromide concentration may also need to be considered. Understanding how reactivity is correlated to SUVA may allow utilities to optimize the degree of treatment required to comply with DBP regulations. The reactive components that require removal, and the degree of treatment necessary to accomplish this removal, may be directly obtained from the relationship between SUVA removal and the degree of treatment (e.g., alum dose).

Optical properties of ordered vertical arrays of multi-walled carbon nanotubes from FDTD simulations.

PubMed

Bao, Hua; Ruan, Xiulin; Fisher, Timothy S

2010-03-15

A finite-difference time-domain (FDTD) method is used to model thermal radiative properties of vertical arrays of multi-walled carbon nanotubes (MWCNT). Individual CNTs are treated as solid circular cylinders with an effective dielectric tensor. Consistent with experiments, the results confirm that CNT arrays are highly absorptive. Compared with the commonly used Maxwell-Garnett theory, the FDTD calculations generally predict larger reflectance and absorbance, and smaller transmittance, which are attributed to the diffraction and scattering within the cylinder array structure. The effects of volume fraction, tube length, tube distance, and incident angle on radiative properties are investigated systematically. Low volume fraction and long tubes are more favorable to achieve low reflectance and high absorbance. For a fixed volume fraction and finite tube length, larger periodicity results in larger reflectance and absorbance. The angular dependence studies reveal an optimum incident angle at which the reflectance can be minimized. The results also suggest that an even darker material could be achieved by using CNTs with good alignment on the top surface.

Variation in blood pressure is associated with white matter microstructure but not cognition in African Americans.

PubMed

Leritz, Elizabeth C; Salat, David H; Milberg, William P; Williams, Victoria J; Chapman, Caroline E; Grande, Laura J; Rudolph, James L; Schnyer, David M; Barber, Colleen E; Lipsitz, Lewis A; McGlinchey, Regina E

2010-03-01

Although hypertension is a major risk factor for cerebrovascular disease (CVD) and is highly prevalent in African Americans, little is known about how blood pressure (BP) affects brain-behavior relationships in this population. In predominantly Caucasian populations, high BP is associated with alterations in frontal-subcortical white matter and in executive functioning aspects of cognition. We investigated associations among BP, brain structure, and neuropsychological functioning in 52 middle-older-age African Americans without diagnosed history of CVD. All participants underwent diffusion tensor imaging for examination of white matter integrity, indexed by fractional anisotropy (FA). Three regions of interest were derived in the anterior (genu) and posterior (splenium) corpus callosum and across the whole brain. A brief neuropsychological battery was administered from which composite scores of executive function and memory were derived. Blood pressure was characterized by mean arterial blood pressure (MABP). When controlling for age, higher MABP was associated with lower FA in the genu, and there was a trend for this same relationship with regard to whole-brain FA. When the sample was broken into groups on the basis of treatment for BP regulation (medicated vs. nonmedicated), MABP was related to genu and whole-brain FA only in the nonmedicated group. Neither MABP nor FA was significantly related to either neuropsychological composite score regardless of medication use. These data provide important evidence that variation in BP may contribute to significant alterations in specific neural regions of white matter in nonmedicated individuals without symptoms of overt CVD. Copyright 2010 APA, all rights reserved

Motor function outcomes of pediatric patients with hemiplegic cerebral palsy after rehabilitation treatment: a diffusion tensor imaging study

PubMed Central

Kim, Jin Hyun; Kwon, Yong Min; Son, Su Min

2015-01-01

Previous diffusion tensor imaging (DTI) studies regarding pediatric patients with motor dysfunction have confirmed the correlation between DTI parameters of the injured corticospinal tract and the severity of motor dysfunction. There is also evidence that DTI parameters can help predict the prognosis of motor function of patients with cerebral palsy. But few studies are reported on the DTI parameters that can reflect the motor function outcomes of pediatric patients with hemiplegic cerebral palsy after rehabilitation treatment. In the present study, 36 pediatric patients with hemiplegic cerebral palsy were included. Before and after rehabilitation treatment, DTI was used to measure the fiber number (FN), fractional anisotropy (FA) and apparent diffusion coefficient (ADC) of bilateral corticospinal tracts. Functional Level of Hemiplegia scale (FxL) was used to assess the therapeutic effect of rehabilitative therapy on clinical hemiplegia. Correlation analysis was performed to assess the statistical interrelationship between the change amount of DTI parameters and FxL. DTI findings obtained at the initial and follow-up evaluations demonstrated that more affected corticospinal tract yielded significantly decreased FN and FA values and significantly increased ADC value compared to the less affected corticospinal tract. Correlation analysis results showed that the change amount of FxL was positively correlated to FN and FA values, and the correlation to FN was stronger than the correlation to FA. The results suggest that FN and FA values can be used to evaluate the motor function outcomes of pediatric patients with hemiplegic cerebral palsy after rehabilitation treatment and FN is of more significance for evaluation. PMID:26170825

Impaired empathic abilities and reduced white matter integrity in schizophrenia.

PubMed

Fujino, Junya; Takahashi, Hidehiko; Miyata, Jun; Sugihara, Genichi; Kubota, Manabu; Sasamoto, Akihiko; Fujiwara, Hironobu; Aso, Toshihiko; Fukuyama, Hidenao; Murai, Toshiya

2014-01-03

Empathic abilities are impaired in schizophrenia. Although the pathology of schizophrenia is thought to involve disrupted white matter integrity, the relationship between empathic disabilities and altered white matter in the disorder remains unclear. The present study tested associations between empathic disabilities and white matter integrity in order to investigate the neural basis of impaired empathy in schizophrenia. Sixty-nine patients with schizophrenia and 69 age-, gender-, handedness-, education- and IQ level-matched healthy controls underwent diffusion-weighted imaging. Empathic abilities were assessed using the Interpersonal Reactivity Index (IRI). Using tract-based spatial statistics (TBSS), the associations between empathic abilities and white matter fractional anisotropy (FA), a measure of white matter integrity, were examined in the patient group within brain areas that showed a significant FA reduction compared with the controls. The patients with schizophrenia reported lower perspective taking and higher personal distress according to the IRI. The patients showed a significant FA reduction in bilateral deep white matter in the frontal, temporal, parietal and occipital lobes, a large portion of the corpus callosum, and the corona radiata. In schizophrenia patients, fantasy subscales positively correlated with FA in the left inferior fronto-occipital fasciculi and anterior thalamic radiation, and personal distress subscales negatively correlated with FA in the splenium of the corpus callosum. These results suggest that disrupted white matter integrity in these regions constitutes a pathology underpinning specific components of empathic disabilities in schizophrenia, highlighting that different aspects of empathic impairments in the disorder would have, at least partially, distinct neuropathological bases. © 2013.

Deviant white matter structure in adults with attention-deficit/hyperactivity disorder points to aberrant myelination and affects neuropsychological performance.

PubMed

Onnink, A Marten H; Zwiers, Marcel P; Hoogman, Martine; Mostert, Jeanette C; Dammers, Janneke; Kan, Cornelis C; Vasquez, Alejandro Arias; Schene, Aart H; Buitelaar, Jan; Franke, Barbara

2015-12-03

Attention-deficit/hyperactivity disorder (ADHD) in childhood is characterized by gray and white matter abnormalities in several brain areas. Considerably less is known about white matter microstructure in adults with ADHD and its relation with clinical symptoms and cognitive performance. In 107 adult ADHD patients and 109 gender-, age- and IQ-matched controls, we used diffusion tensor imaging (DTI) with tract-based spatial statistics (TBSS) to investigate whole-skeleton changes of fractional anisotropy (FA) and mean, axial, and radial diffusivity (MD, AD, RD). Additionally, we studied the relation of FA and MD values with symptom severity and cognitive performance on tasks measuring working memory, attention, inhibition, and delay discounting. In comparison to controls, participants with ADHD showed reduced FA in corpus callosum, bilateral corona radiata, and thalamic radiation. Higher MD and RD were found in overlapping and even more widespread areas in both hemispheres, also encompassing internal and external capsule, sagittal stratum, fornix, and superior lateral fasciculus. Values of FA and MD were not associated with symptom severity. However, within some white matter clusters that distinguished patients from controls, worse inhibition performance was associated with reduced FA and more impulsive decision making was associated with increased MD. This study shows widespread differences in white matter integrity between adults with persistent ADHD and healthy individuals. Changes in RD suggest aberrant myelination as a pathophysiological factor in persistent ADHD. The microstructural differences in adult ADHD may contribute to poor inhibition and greater impulsivity but appear to be independent of disease severity. Copyright © 2015. Published by Elsevier Inc.

Lower Working Memory Performance in Overweight and Obese Adolescents Is Mediated by White Matter Microstructure

PubMed Central

Alarcón, Gabriela; Ray, Siddharth; Nagel, Bonnie J.

2017-01-01

Objectives Elevated body mass index (BMI) is associated with deficits in working memory, reduced gray matter volume in frontal and parietal lobes, as well as changes in white matter (WM) microstructure. The current study examined whether BMI was related to working memory performance and blood oxygen level dependent (BOLD) activity, as well as WM microstructure during adolescence. Methods Linear regressions with BMI and (1) verbal working memory BOLD signal, (2) spatial working memory BOLD signal, and (3) fractional anisotropy (FA), a measure of WM microstructure, were conducted in a sample of 152 healthy adolescents ranging in BMI. Results BMI was inversely related to IQ and verbal and spatial working memory accuracy; however, there was no significant relationship between BMI and BOLD response for either verbal or spatial working memory. Furthermore, BMI was negatively correlated with FA in the left superior longitudinal fasciculus (SLF) and left inferior longitudinal fasciculus (ILF). ILF FA and IQ significantly mediated the relationship between BMI and verbal working memory performance, whereas SLF FA, but not IQ, significantly mediated the relationship between BMI and accuracy of both verbal and spatial working memory. Conclusions These findings indicate that higher BMI is associated with decreased FA in WM fibers connecting brain regions that support working memory, and that WM microstructural deficits may underlie inferior working memory performance in youth with higher BMI. Of interest, BMI did not show the same relationship with working memory BOLD activity, which may indicate that changes in brain structure precede changes in function. PMID:26708324

Diagnostic Validity of an Automated Probabilistic Tractography in Amnestic Mild Cognitive Impairment

PubMed Central

Jung, Won Sang; Um, Yoo Hyun; Kang, Dong Woo; Lee, Chang Uk; Woo, Young Sup; Bahk, Won-Myong

2018-01-01

Objective Although several prior works showed the white matter (WM) integrity changes in amnestic mild cognitive impairment (aMCI) and Alzheimer’s disease, it is still unclear the diagnostic accuracy of the WM integrity measurements using diffusion tensor imaging (DTI) in discriminating aMCI from normal controls. The aim of this study is to explore diagnostic validity of whole brain automated probabilistic tractography in discriminating aMCI from normal controls. Methods One hundred-two subjects (50 aMCI and 52 normal controls) were included and underwent DTI scans. Whole brain WM tracts were reconstructed with automated probabilistic tractography. Fractional anisotropy (FA) and mean diffusivity (MD) values of the memory related WM tracts were measured and compared between the aMCI and the normal control groups. In addition, the diagnostic validities of these WM tracts were evaluated. Results Decreased FA and increased MD values of memory related WM tracts were observed in the aMCI group compared with the control group. Among FA and MD value of each tract, the FA value of left cingulum angular bundle showed the highest area under the curve (AUC) of 0.85 with a sensitivity of 88.2%, a specificity of 76.9% in differentiating MCI patients from control subjects. Furthermore, the combination FA values of WM integrity measures of memory related WM tracts showed AUC value of 0.98, a sensitivity of 96%, a specificity of 94.2%. Conclusion Our results with good diagnostic validity of WM integrity measurements suggest DTI might be promising neuroimaging tool for early detection of aMCI and AD patients. PMID:29739127

Limbic-Auditory Interactions of Tinnitus: An Evaluation Using Diffusion Tensor Imaging.

PubMed

Gunbey, H P; Gunbey, E; Aslan, K; Bulut, T; Unal, A; Incesu, L

2017-06-01

Tinnitus is defined as an imaginary subjective perception in the absence of an external sound. Convergent evidence proposes that tinnitus perception includes auditory, attentional and emotional components. The aim of this study was to investigate the thalamic, auditory and limbic interactions associated with tinnitus-related distress by Diffusion Tensor Imaging (DTI). A total of 36 tinnitus patients, 20 healthy controls underwent an audiological examination, as well as a magnetic resonance imaging protocol including structural and DTI sequences. All participants completed the Tinnitus Handicap Inventory (THI) and Visual Analog Scales (VAS) related with tinnitus. The fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were obtained for the auditory cortex (AC), inferior colliculus (IC), lateral lemniscus (LL), medial geniculate body (MGB), thalamic reticular nucleus (TRN), amygdala (AMG), hippocampus (HIP), parahippocampus (PHIP) and prefrontal cortex (PFC). In tinnitus patients the FA values of IC, MGB, TRN, AMG, HIP decreased and the ADC values of IC, MGB, TRN, AMG, PHIP increased significantly. The contralateral IC-LL and bilateral MGB FA values correlated negatively with hearing loss. A negative relation was found between the AMG-HIP FA values and THI and VAS scores. Bilateral ADC values of PHIP and PFC significantly correlated with the attention deficiency-VAS scores. In conclusion, this is the first DTI study to investigate the grey matter structures related to tinnitus perception and the significant correlation of FA and ADC with clinical parameters suggests that DTI can provide helpful information for tinnitus. Magnifying the microstructures in DTI can help evaluate the three faces of tinnitus nature: hearing, emotion and attention.

Atypical Frontal-Striatal-Thalamic Circuit White Matter Development in Pediatric Obsessive Compulsive Disorder

PubMed Central

Fitzgerald, Kate D.; Liu, Yanni; Reamer, Elyse N.; Taylor, Stephan F.; Welsh, Robert C.

2015-01-01

Objective Atypical development of frontal-striatal-thalamic circuitry (FSTC) has been hypothesized to underlie the early course of obsessive-compulsive disorder (OCD); however, the development of FSTC white matter tracts remains to be studied in young patients. Method To address this gap, we scanned 36 patients with pediatric OCD compared to 27 healthy controls, aged 8 to 19 years, with diffusion tensor imaging (DTI) to measure fractional anisotropy (FA), an index of white matter coherence. Tract-based spatial statistics (TBSS) were used to test differential effects of age on FA, across the whole brain, in those with OCD compared to healthy youth, followed by analyses in a priori regions of interest (anterior corpus callosum, anterior cingulum bundle and anterior limb of the internal capsule [ALIC]) to further characterize developmental differences between groups. Results Patients with OCD showed more pronounced age-related increases in FA than controls in regions of interest, as well as several other white matter tracts. In patients, greater FA in anterior cingulum bundle correlated with more severe symptoms after controlling for age. Conclusions Our findings support theories of atypical FSTC maturation in pediatric OCD by providing the first evidence for altered trajectories of white matter development in anterior corpus callosum, anterior cingulum bundle, and ALIC in young patients. Steeper age-related increases of FA in these and other select white matter tracts in OCD, compared to healthy controls, may derive from an early delay in white matter development and/or prolonged white matter growth, but confirmation of these possibilities awaits longitudinal work. PMID:25440312

Tract-Specific Diffusion Tensor Imaging Reveals Laterality of Neurological Symptoms in Patients with Cervical Compression Myelopathy.

PubMed

Maki, Satoshi; Koda, Masao; Saito, Junya; Takahashi, Sho; Inada, Taigo; Kamiya, Koshiro; Ota, Mitsutoshi; Iijima, Yasushi; Masuda, Yoshitada; Matsumoto, Koji; Kojima, Masatoshi; Takahashi, Kazuhisa; Obata, Takayuki; Yamazaki, Masashi; Furuya, Takeo

2016-12-01

Patients with cervical compression myelopathy (CCM) generally present bilateral neurological symptoms in their extremities. However, a substantial portion of patients with CCM exhibit laterality of neurological symptoms. The aim of this study was to assess the correlation between intrinsic structural damage and laterality of symptoms using spinal cord diffusion tensor imaging (DTI) of the corticospinal tract. We enrolled 10 healthy volunteers and 40 patients with CCM in this study. We evaluated motor function using the American Spinal Injury Association (ASIA) motor score for left and right extremities. For DTI acquisitions, a 3.0-T magnetic resonance imaging system with diffusion-weighted spin-echo sequence was used. Regions-of-interest in the lateral column tracts were determined. We determined the correlations between fractional anisotropy (FA) and ASIA motor scores. An FA asymmetry index was calculated using left and right regions-of-interest. Four patients exhibited laterality of symptoms in their extremities, for which left and right ASIA scores correlated moderately with FA in the left and right lateral columns, respectively (left: ρ = 0.64, P < 0.001; right: ρ = 0.67, P < 0.001). The area under the receiver-operator characteristic curve showed that the FA asymmetry index indicated laterality of symptoms. Using tract-specific DTI, we demonstrated that microstructural damages in the left and right corticospinal tracts correlated with corresponding neurological symptoms in the ipsilateral side and the FA asymmetry index could indicate laterality in neurological symptoms of patients with CCM. Copyright © 2016 Elsevier Inc. All rights reserved.

Overexpression of a BAHD Acyltransferase, OsAt10, Alters Rice Cell Wall Hydroxycinnamic Acid Content and Saccharification1[C][W][OA

PubMed Central

Bartley, Laura E.; Peck, Matthew L.; Kim, Sung-Ryul; Ebert, Berit; Manisseri, Chithra; Chiniquy, Dawn M.; Sykes, Robert; Gao, Lingfang; Rautengarten, Carsten; Vega-Sánchez, Miguel E.; Benke, Peter I.; Canlas, Patrick E.; Cao, Peijian; Brewer, Susan; Lin, Fan; Smith, Whitney L.; Zhang, Xiaohan; Keasling, Jay D.; Jentoff, Rolf E.; Foster, Steven B.; Zhou, Jizhong; Ziebell, Angela; An, Gynheung; Scheller, Henrik V.; Ronald, Pamela C.

2013-01-01

Grass cell wall properties influence food, feed, and biofuel feedstock usage efficiency. The glucuronoarabinoxylan of grass cell walls is esterified with the phenylpropanoid-derived hydroxycinnamic acids ferulic acid (FA) and para-coumaric acid (p-CA). Feruloyl esters undergo oxidative coupling with neighboring phenylpropanoids on glucuronoarabinoxylan and lignin. Examination of rice (Oryza sativa) mutants in a grass-expanded and -diverged clade of BAHD acyl-coenzyme A-utilizing transferases identified four mutants with altered cell wall FA or p-CA contents. Here, we report on the effects of overexpressing one of these genes, OsAt10 (LOC_Os06g39390), in rice. An activation-tagged line, OsAT10-D1, shows a 60% reduction in matrix polysaccharide-bound FA and an approximately 300% increase in p-CA in young leaf tissue but no discernible phenotypic alterations in vegetative development, lignin content, or lignin composition. Two additional independent OsAt10 overexpression lines show similar changes in FA and p-CA content. Cell wall fractionation and liquid chromatography-mass spectrometry experiments isolate the cell wall alterations in the mutant to ester conjugates of a five-carbon sugar with p-CA and FA. These results suggest that OsAT10 is a p-coumaroyl coenzyme A transferase involved in glucuronoarabinoxylan modification. Biomass from OsAT10-D1 exhibits a 20% to 40% increase in saccharification yield depending on the assay. Thus, OsAt10 is an attractive target for improving grass cell wall quality for fuel and animal feed. PMID:23391577

Soccer Heading Is Associated with White Matter Microstructural and Cognitive Abnormalities

PubMed Central

Kim, Namhee; Zimmerman, Molly E.; Kim, Mimi; Stewart, Walter F.; Branch, Craig A.

2013-01-01

Purpose: To investigate the association of soccer heading with subclinical evidence of traumatic brain injury. Materials and Methods: With institutional review board approval and compliance with HIPAA guidelines, 37 amateur soccer players (mean age, 30.9 years; 78% [29] men, 22% [eight] women) gave written informed consent and completed a questionnaire to quantify heading in the prior 12 months and lifetime concussions. Diffusion-tensor magnetic resonance (MR) imaging at 3.0 T was performed (32 directions; b value, 800 sec/mm2; 2 × 2 × 2-mm voxels). Cognitive function was measured by using a computerized battery of tests. Voxelwise linear regression (heading vs fractional anisotropy [FA]) was applied to identify significant regional associations. FA at each location and cognition were tested for a nonlinear relationship to heading by using an inverse logit model that incorporated demographic covariates and history of concussion. Results: Participants had headed 32–5400 times (median, 432 times) over the previous year. Heading was associated with lower FA at three locations in temporo-occipital white matter with a threshold that varied according to location (885–1550 headings per year) (P < .00001). Lower levels of FA were also associated with poorer memory scores (P < .00001), with a threshold of 1800 headings per year. Lifetime concussion history and demographic features were not significantly associated with either FA or cognitive performance. Conclusion: Heading is associated with abnormal white matter microstructure and with poorer neurocognitive performance. This relationship is not explained by a history of concussion. © RSNA, 2013 PMID:23757503

The Disconnection Hypothesis in Alzheimer's Disease Studied Through Multimodal Magnetic Resonance Imaging: Structural, Perfusion, and Diffusion Tensor Imaging.

PubMed

Lacalle-Aurioles, María; Navas-Sánchez, Francisco Javier; Alemán-Gómez, Yasser; Olazarán, Javier; Guzmán-De-Villoria, Juan Adán; Cruz-Orduña, Isabel; Mateos-Pérez, José María; Desco, Manuel

2016-01-01

According to the so-called disconnection hypothesis, the loss of synaptic inputs from the medial temporal lobes (MTL) in Alzheimer's disease (AD) may lead to reduced activity of target neurons in cortical areas and, consequently, to decreased cerebral blood flow (CBF) in those areas. The aim of this study was to assess whether hypoperfusion in parietotemporal and frontal cortices of patients with mild cognitive impairment who converted to AD (MCI-c) and patients with mild AD is associated with atrophy in the MTL and/or microstructural changes in the white matter (WM) tracts connecting these areas. We assessed these relationships by investigating correlations between CBF in hypoperfused areas, mean cortical thickness in atrophied regions of the MTL, and fractional anisotropy (FA) in WM tracts. In the MCI-c group, a strong correlation was observed between CBF of the superior parietal gyri and FA in the parahippocampal tracts (left: r = 0.90, p <  0.0001; right: r = 0.597, p = 0.024), and between FA in the right parahippocampal tract and the right precuneus (r = 0.551, p = 0.041). No significant correlations between CBF in hypoperfused regions and FA in the WM tract were observed in the AD group. These results suggest an association between perfusion deficits and altered WM tracts in prodromal AD, while microvasculature impairments may have a greater influence in more advanced stages. We did not find correlations between cortical thinning in the medial temporal lobes and decreased FA in the WM tracts of the limbic system in either group.

Correlation of diffusion tensor imaging parameters with neural status in Pott's spine.

PubMed

Jain, Nikhil; Saini, Namita Singh; Kumar, Sudhir; Rajagopalan, Mukunth; Chakraborti, Kanti Lal; Jain, Anil Kumar

2016-04-29

Diffusion tensor imaging (DTI) has been used in cervical trauma and spondylotic myelopathy, and it has been found to correlate with neural deficit and prognosticate neural recovery. Such a correlation has not been studied in Pott's spine with paraplegia. Hence, this prospective study has been used to find correlation of DTI parameters with neural deficit in these patients. Thirty-four patients of spinal TB were enrolled and DTI was performed before the start of treatment and after six months. Fractional anisotropy (FA), Mean diffusivity (MD), and Tractography were studied. Neurological deficit was graded by the Jain and Sinha scoring. Changes in FA and MD at and below the site of lesion (SOL) were compared to above the SOL (control) using the unpaired t-test. Pre-treatment and post-treatment values were also compared using the paired t-test. Correlation of DTI parameters with neurological score was done by Pearson's correlation. Subjective assessment of Tractography images was done. Mean average FA was not significantly decreased at the SOL in patients with paraplegia as compared to control. After six months of treatment, a significant decrease (p = 0.02) in mean average FA at the SOL compared to pre-treatment was seen. Moderate positive correlation (r = 0.49) between mean average FA and neural score after six months of treatment was found. Tractography images were not consistent with severity of paraplegia. Unlike spondylotic myelopathy and trauma, epidural collection and its organized inflammatory tissue in Pott's spine precludes accurate assessment of diffusion characteristics of the compressed cord.

Quantification of diffusion tensor imaging in normal white matter maturation of early childhood using an automated processing pipeline.

PubMed

Loh, K B; Ramli, N; Tan, L K; Roziah, M; Rahmat, K; Ariffin, H

2012-07-01

The degree and status of white matter myelination can be sensitively monitored using diffusion tensor imaging (DTI). This study looks at the measurement of fractional anistropy (FA) and mean diffusivity (MD) using an automated ROI with an existing DTI atlas. Anatomical MRI and structural DTI were performed cross-sectionally on 26 normal children (newborn to 48 months old), using 1.5-T MRI. The automated processing pipeline was implemented to convert diffusion-weighted images into the NIfTI format. DTI-TK software was used to register the processed images to the ICBM DTI-81 atlas, while AFNI software was used for automated atlas-based volumes of interest (VOIs) and statistical value extraction. DTI exhibited consistent grey-white matter contrast. Triphasic temporal variation of the FA and MD values was noted, with FA increasing and MD decreasing rapidly early in the first 12 months. The second phase lasted 12-24 months during which the rate of FA and MD changes was reduced. After 24 months, the FA and MD values plateaued. DTI is a superior technique to conventional MR imaging in depicting WM maturation. The use of the automated processing pipeline provides a reliable environment for quantitative analysis of high-throughput DTI data. Diffusion tensor imaging outperforms conventional MRI in depicting white matter maturation. • DTI will become an important clinical tool for diagnosing paediatric neurological diseases. • DTI appears especially helpful for developmental abnormalities, tumours and white matter disease. • An automated processing pipeline assists quantitative analysis of high throughput DTI data.

White matter tract integrity and intelligence in patients with mental retardation and healthy adults.

PubMed

Yu, Chunshui; Li, Jun; Liu, Yong; Qin, Wen; Li, Yonghui; Shu, Ni; Jiang, Tianzi; Li, Kuncheng

2008-05-01

It is well known that brain structures correlate with intelligence but the association between the integrity of brain white matter tracts and intelligence in patients with mental retardation (MR) and healthy adults remains unknown. The aims of this study are to investigate whether the integrity of corpus callosum (CC), cingulum, uncinate fasciculus (UF), optic radiation (OR) and corticospinal tract (CST) are damaged in patients with MR, and to determine the correlations between the integrity of these tracts and full scale intelligence quotient (FSIQ) in both patients and controls. Fifteen MR patients and 79 healthy controls underwent intelligence tests and diffusion tensor imaging examinations. According to the FSIQ, all healthy controls were divided into general intelligence (GI: FSIQ<120; n=42) and high intelligence (HI: FSIQ> or =120; n=37) groups. Intelligence was assessed by Chinese Revised Wechsler Adult Intelligence Scale, and white matter tract integrity was assessed by fractional anisotropy (FA). MR patients showed significantly lower FA than healthy controls in the CC, UF, OR and CST. However, GI subjects only demonstrated lower FA than HI subjects in the right UF. Partial correlation analysis controlling for age and sex showed that FSIQ scores were significantly correlated with the FA of the bilateral UF, genu and truncus of CC, bilateral OR and left CST. While FSIQ scores were only significantly correlated with the FA of the right UF when further controlling for group. This study indicate that MR patients show extensive damage in the integrity of the brain white matter tracts, and the right UF is an important neural basis of human intelligence.

Optimum Solar Conversion Cell Configurations

NASA Technical Reports Server (NTRS)

Chen, Bin (Inventor)

2015-01-01

Methods for maximizing a fraction of light energy absorbed in each of three classes of light concentrators (rectangular parallelepipeds, paraboloids and prisms) by choice of incident angle of radiation and of one or more geometrical or physical parameters (absorber thickness, paraboloid dimensions, location of paraboloid focus, prism angles, concentrator material, cladding, prism angles, etc.). Alternatively, the light energy absorbed plus the light energy that escapes through non-total internal reflection within the light concentrator can be minimized.

Effect of grape seed extract, Cistus ladanifer L., and vegetable oil supplementation on fatty acid composition of abomasal digesta and intramuscular fat of lambs.

PubMed

Jerónimo, Eliana; Alves, Susana P; Dentinho, Maria T P; Martins, Susana V; Prates, José A M; Vasta, Valentina; Santos-Silva, José; Bessa, Rui J B

2010-10-13

Thirty-six lambs were used in a 6 week experiment to evaluate the effect of vegetable oil blend supplementation (0 vs 60 g/kg of dry matter (DM)) and two dietary condensed tannin sources, grape seed extract (0 vs 25 g/kg of DM) and Cistus ladanifer L. (0 vs 250 g/kg of DM), on fatty acid (FA) composition of abomasal digesta and intramuscular polar and neutral lipids. Grape seed extract did not affect the FA profile of abomasal digesta or muscle lipid fractions. C. ladanifer had a minor effect in lambs fed diets with no oil but greatly changed the abomasal and muscle FA profiles in oil-supplemented lambs. It decreased 18:0 and increased 18:1 trans-11 in abomasal digesta and increased 18:1 trans-11 and 18:2 cis-9,trans-11 (P = 0.062) in muscle neutral lipids, resulting in an important enrichment of meat 18:2 cis-9,trans-11 when compared to other oil-supplemented diets (19.2 vs 41.7 mg/100 g of muscle).

White matter integrity in Asperger syndrome: a preliminary diffusion tensor magnetic resonance imaging study in adults.

PubMed

Bloemen, Oswald J N; Deeley, Quinton; Sundram, Fred; Daly, Eileen M; Barker, Gareth J; Jones, Derek K; van Amelsvoort, Therese A M J; Schmitz, Nicole; Robertson, Dene; Murphy, Kieran C; Murphy, Declan G M

2010-10-01

Autistic Spectrum Disorder (ASD), including Asperger syndrome and autism, is a highly genetic neurodevelopmental disorder. There is a consensus that ASD has a biological basis, and it has been proposed that it is a "connectivity" disorder. Diffusion Tensor Magnetic Resonance Imaging (DT-MRI) allows measurement of the microstructural integrity of white matter (a proxy measure of "connectivity"). However, nobody has investigated the microstructural integrity of whole brain white matter in people with Asperger syndrome. We measured the fractional anisotropy (FA), mean diffusivity (MD) and radial diffusivity (RD) of white matter, using DT-MRI, in 13 adults with Asperger syndrome and 13 controls. The groups did not differ significantly in overall intelligence and age. FA, MD and RD were assessed using whole brain voxel-based techniques. Adults with Asperger syndrome had a significantly lower FA than controls in 13 clusters. These were largely bilateral and included white matter in the internal capsule, frontal, temporal, parietal and occipital lobes, cingulum and corpus callosum. Adults with Asperger syndrome have widespread significant differences from controls in white matter microstructural integrity.

Increased left hemisphere impairment in high-functioning autism: a tract based spatial statistics study.

PubMed

Perkins, Thomas John; Stokes, Mark Andrew; McGillivray, Jane Anne; Mussap, Alexander Julien; Cox, Ivanna Anne; Maller, Jerome Joseph; Bittar, Richard Garth

2014-11-30

There is evidence emerging from Diffusion Tensor Imaging (DTI) research that autism spectrum disorders (ASD) are associated with greater impairment in the left hemisphere. Although this has been quantified with volumetric region of interest analyses, it has yet to be tested with white matter integrity analysis. In the present study, tract based spatial statistics was used to contrast white matter integrity of 12 participants with high-functioning autism or Aspergers syndrome (HFA/AS) with 12 typically developing individuals. Fractional Anisotropy (FA) was examined, in addition to axial, radial and mean diffusivity (AD, RD and MD). In the left hemisphere, participants with HFA/AS demonstrated significantly reduced FA in predominantly thalamic and fronto-parietal pathways and increased RD. Symmetry analyses confirmed that in the HFA/AS group, WM disturbance was significantly greater in the left compared to right hemisphere. These findings contribute to a growing body of literature suggestive of reduced FA in ASD, and provide preliminary evidence for RD impairments in the left hemisphere. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Cortical gray and subcortical white matter associations in Parkinson's disease.

PubMed

Sterling, Nicholas W; Du, Guangwei; Lewis, Mechelle M; Swavely, Steven; Kong, Lan; Styner, Martin; Huang, Xuemei

2017-01-01

Cortical atrophy has been documented in both Parkinson's disease (PD) and healthy aging, but its relationship to changes in subcortical white matter is unknown. This was investigated by obtaining T1- and diffusion-weighted images from 76 PD and 70 controls at baseline and 18 and 36 months, from which cortical volumes and underlying subcortical white matter axial diffusivity (AD), radial diffusivity (RD), and fractional anisotropy (FA) were determined. Twelve of 69 cortical subregions had significant group differences, and for these, underlying subcortical white matter was explored. At baseline, higher cortical volumes were significantly correlated with lower underlying subcortical white matter AD, RD, and higher FA (ps ≤ 0.017) in PD. Longitudinally, higher rates of cortical atrophy in PD were associated with increased rates of change in AD RD, and FA values (ps ≤ 0.0013) in 2 subregions explored. The significant gray-white matter associations were not found in controls. Thus, unlike healthy aging, cortical atrophy and subcortical white matter changes may not be independent events in PD. Copyright © 2016 Elsevier Inc. All rights reserved.

Diffusion tensor imaging of the inferior colliculus and brainstem auditory-evoked potentials in preterm infants.

PubMed

Reiman, Milla; Parkkola, Riitta; Johansson, Reijo; Jääskeläinen, Satu K; Kujari, Harry; Lehtonen, Liisa; Haataja, Leena; Lapinleimu, Helena

2009-08-01

Preterm and low-birth-weight infants have an increased risk of sensorineural hearing loss. Brainstem auditory-evoked potentials (BAEP) are an effective method to detect subtle deficits in impulse conduction in the auditory pathway. Abnormalities on diffusion tensor imaging (DTI) have been shown to be associated with perinatal white-matter injury and reduced fractional anisotropy (FA) has been reported in patients with sensorineural hearing loss. To evaluate the possibility of a correlation between BAEP and DTI of the inferior colliculus in preterm infants. DTI at term age and BAEP measurements were performed on all very-low-birth-weight or very preterm study infants (n=56). FA and apparent diffusion coefficient (ADC) of the inferior colliculus were measured from the DTI. Shorter BAEP wave I, III, and V latencies and I-III and I-V intervals and higher wave V amplitude correlated with higher FA of the inferior colliculus. The association between the DTI findings of the inferior colliculus and BAEP responses suggests that DTI can be used to assess the integrity of the auditory pathway in preterm infants.

Snowy backgrounds enhance the absorption of visible light in forest canopies

NASA Astrophysics Data System (ADS)

Pinty, B.; Widlowski, J.-L.; Verstraete, M. M.; Andredakis, I.; Arino, O.; Clerici, M.; Kaminski, T.; Taberner, M.

2011-03-01

The fraction of radiation absorbed in the canopy depends on the amount and angular distribution of the solar irradiance reaching the top of the canopy as well as the fraction of this irradiance that is transmitted through the canopy gaps and reflected back to the vegetation by the background. This contribution shows that the presence of snow on forest floors enhances the fraction of absorbed Photosynthetically Active Radiation (PAR). A global analysis of satellite-derived products reveals that this enhancement affects evergreen and deciduous forests of the boreal zone. This snow-related effect may usefully contribute to the photosynthesis process in evergreen forests especially during spring time when radiation conditions are marginal but other physiological constraints (such as temperature) permit the necessary biochemical functions to take place.

Fine Motor Skill Mediates Visual Memory Ability with Microstructural Neuro-correlates in Cerebellar Peduncles in Prematurely Born Adolescents.

PubMed

Thomas, Alyssa R; Lacadie, Cheryl; Vohr, Betty; Ment, Laura R; Scheinost, Dustin

2017-01-01

Adolescents born preterm (PT) with no evidence of neonatal brain injury are at risk of deficits in visual memory and fine motor skills that diminish academic performance. The association between these deficits and white matter microstructure is relatively unexplored. We studied 190 PTs with no brain injury and 92 term controls at age 16 years. The Rey-Osterrieth Complex Figure Test (ROCF), the Beery visual-motor integration (VMI), and the Grooved Pegboard Test (GPT) were collected for all participants, while a subset (40 PTs and 40 terms) underwent diffusion-weighted magnetic resonance imaging. PTs performed more poorly than terms on ROCF, VMI, and GPT (all P < 0.01). Mediation analysis showed fine motor skill (GPT score) significantly mediates group difference in ROCF and VMI (all P < 0.001). PTs showed a negative correlation (P < 0.05, corrected) between fractional anisotropy (FA) in the bilateral middle cerebellar peduncles and GPT score, with higher FA correlating to lower (faster task completion) GPT scores, and between FA in the right superior cerebellar peduncle and ROCF scores. PTs also had a positive correlation (P < 0.05, corrected) between VMI and left middle cerebellar peduncle FA. Novel strategies to target fine motor skills and the cerebellum may help PTs reach their full academic potential. © The Author 2017. Published by Oxford University Press.

Role of Frontotemporal Fiber Tract Integrity in Task-Switching Performance of Healthy Controls and Patients with Temporal Lobe Epilepsy

PubMed Central

Kucukboyaci, N. Erkut; Girard, H.M.; Hagler, D.J.; Kuperman, J.; Tecoma, E.S.; Iragui, V.J.; Halgren, E.; McDonald, C.R.

2012-01-01

The objective of this study is to investigate the relationships among frontotemporal fiber tract compromise and task-switching performance in healthy controls and patients with temporal lobe epilepsy (TLE). We performed diffusion tensor imaging (DTI) on 30 controls and 32 patients with TLE (15 left TLE). Fractional anisotropy (FA) was calculated for four fiber tracts [uncinate fasciculus (UncF), arcuate fasciculus (ArcF), dorsal cingulum (CING), and inferior fronto-occipital fasciculus (IFOF)]. Participants completed the Trail Making Test-B (TMT-B) and Verbal Fluency Category Switching (VFCS) test. Multivariate analyses of variances (MANOVAs) were performed to investigate group differences in fiber FA and set-shifting performances. Canonical correlations were used to examine the overall patterns of structural-cognitive relationships and were followed by within-group bivariate correlations. We found a significant canonical correlation between fiber FA and task-switching performance. In controls, TMT-B correlated with left IFOF, whereas VFCS correlated with FA of left ArcF and left UncF. These correlations were not significant in patients with TLE. We report significant correlations between frontotemporal fiber tract integrity and set-shifting performance in healthy controls that appear to be absent or attenuated in patients with TLE. These findings suggest a breakdown of typical structure-function relationships in TLE that may reflect aberrant developmental or degenerative processes. PMID:22014246

Evaluating multicenter DTI data in Huntington's disease on site specific effects: An ex post facto approach☆

PubMed Central

Müller, Hans-Peter; Grön, Georg; Sprengelmeyer, Reiner; Kassubek, Jan; Ludolph, Albert C.; Hobbs, Nicola; Cole, James; Roos, Raymund A.C.; Duerr, Alexandra; Tabrizi, Sarah J.; Landwehrmeyer, G. Bernhard; Süssmuth, Sigurd D.

2013-01-01

Purpose Assessment of the feasibility to average diffusion tensor imaging (DTI) metrics of MRI data acquired in the course of a multicenter study. Materials and methods Sixty-one early stage Huntington's disease patients and forty healthy controls were studied using four different MR scanners at four European sites with acquisition protocols as close as possible to a given standard protocol. The potential and feasibility of averaging data acquired at different sites was evaluated quantitatively by region-of-interest (ROI) based statistical comparisons of coefficients of variation (CV) across centers, as well as by testing for significant group-by-center differences on averaged fractional anisotropy (FA) values between patients and controls. In addition, a whole-brain based statistical between-group comparison was performed using FA maps. Results The ex post facto statistical evaluation of CV and FA-values in a priori defined ROIs showed no differences between sites above chance indicating that data were not systematically biased by center specific factors. Conclusion Averaging FA-maps from DTI data acquired at different study sites and different MR scanner types does not appear to be systematically biased. A suitable recipe for testing on the possibility to pool multicenter DTI data is provided to permit averaging of DTI-derived metrics to differentiate patients from healthy controls at a larger scale. PMID:24179771

Neuropsychiatry and White Matter Microstructure in Huntington's Disease.

PubMed

Gregory, Sarah; Scahill, Rachael I; Seunarine, Kiran K; Stopford, Cheryl; Zhang, Hui; Zhang, Jiaying; Orth, Michael; Durr, Alexandra; Roos, Raymund A C; Langbehn, Douglas R; Long, Jeffrey D; Johnson, Hans; Rees, Geraint; Tabrizi, Sarah J; Craufurd, David

2015-01-01

Neuropsychiatric symptoms in Huntington's disease (HD) are often evident prior to clinical diagnosis. Apathy is highly correlated with disease progression, while depression and irritability occur at different stages of the disease, both before and after clinical onset. Little is understood about the neural bases of these neuropsychiatric symptoms and to what extent those neural bases are analogous to neuropsychiatric disorders in the general population. We used Diffusion Tensor Imaging (DTI) to investigate structural connectivity between brain regions and any putative microstructural changes associated with depression, apathy and irritability in HD. DTI data were collected from 39 premanifest and 45 early-HD participants in the Track-HD study and analysed using whole-brain Tract-Based Spatial Statistics. We used regression analyses to identify white matter tracts whose structural integrity (as measured by fractional anisotropy, FA) was correlated with HADS-depression, PBA-apathy or PBA-irritability scores in gene-carriers and related to cumulative probability to onset (CPO). For those with the highest CPO, we found significant correlations between depression scores and reduced FA in the splenium of the corpus callosum. In contrast, those with lowest CPO demonstrated significant correlations between irritability scores and widespread FA reductions. There was no significant relationship between apathy and FA throughout the whole brain. We demonstrate that white matter changes associated with both depression and irritability in HD occur at different stages of disease progression concomitant with their clinical presentation.

Differential activation of Fyn kinase distinguishes saturated and unsaturated fats in mouse macrophages

PubMed Central

Tarabra, Elena; An Lee, Ting-Wen; Zammit, Victor A.; Vatish, Manu; Yamada, Eijiro; Pessin, Jeffrey E.; Bastie, Claire C.

2017-01-01

Diet-induced obesity is associated with increased adipose tissue activated macrophages. Yet, how macrophages integrate fatty acid (FA) signals remains unclear. We previously demonstrated that Fyn deficiency (fynKO) protects against high fat diet-induced adipose tissue macrophage accumulation. Herein, we show that inflammatory markers and reactive oxygen species are not induced in fynKO bone marrow-derived macrophages exposed to the saturated FA palmitate, suggesting that Fyn regulates macrophage function in response to FA signals. Palmitate activates Fyn and re-localizes Fyn into the nucleus of RAW264.7, J774 and wild-type bone marrow-derived macrophages. Similarly, Fyn activity is increased in cells of adipose tissue stromal vascular fraction of high fat-fed control mice, with Fyn protein being located in the nucleus of these cells. We demonstrate that Fyn modulates palmitate-dependent oxidative stress in macrophages. Moreover, Fyn catalytic activity is necessary for its nuclear re-localization and downstream effects, as Fyn pharmacological inhibition abolishes palmitate-induced Fyn nuclear redistribution and palmitate-dependent increase of oxidative stress markers. Importantly, mono-or polyunsaturated FAs do not activate Fyn, and fail to re-localize Fyn to the nucleus. Together these data demonstrate that macrophages integrate nutritional FA signals via a differential activation of Fyn that distinguishes, at least partly, the effects of saturated versus unsaturated fats. PMID:29156823

Structural abnormality of the corticospinal tract in major depressive disorder

PubMed Central

2014-01-01

Background Scientists are beginning to document abnormalities in white matter connectivity in major depressive disorder (MDD). Recent developments in diffusion-weighted image analyses, including tractography clustering methods, may yield improved characterization of these white matter abnormalities in MDD. In this study, we acquired diffusion-weighted imaging data from MDD participants and matched healthy controls. We analyzed these data using two tractography clustering methods: automated fiber quantification (AFQ) and the maximum density path (MDP) procedure. We used AFQ to compare fractional anisotropy (FA; an index of water diffusion) in these two groups across major white matter tracts. Subsequently, we used the MDP procedure to compare FA differences in fiber paths related to the abnormalities in major fiber tracts that were identified using AFQ. Results FA was higher in the bilateral corticospinal tracts (CSTs) in MDD (p’s < 0.002). Secondary analyses using the MDP procedure detected primarily increases in FA in the CST-related fiber paths of the bilateral posterior limbs of the internal capsule, right superior corona radiata, and the left external capsule. Conclusions This is the first study to implicate the CST and several related fiber pathways in MDD. These findings suggest important new hypotheses regarding the role of CST abnormalities in MDD, including in relation to explicating CST-related abnormalities to depressive symptoms and RDoC domains and constructs. PMID:25295159

Visible light photodegradation of phenanthrene catalyzed by Fe(III)-smectite: role of soil organic matter.

PubMed

Jia, Hanzhong; Li, Li; Fan, Xiaoyun; Liu, Mingdeng; Deng, Wenye; Wang, Chuanyi

2013-07-15

In the present study, phenanthrene is employed as a model to explore the roles played by three soil organic matter (SOM) fractions, i.e., dissolved organic matter (DOM), humic acid (HA), and fulvic acid (FA), in its photodegradation with assistance of Fe(III)-smectite under visible-light. Slight decrease in phenanthrene photodegradation rate was observed in the presence of DOM, which is explained in terms of oxidative-radical competition between DOM and target phenanthrene molecules due to the high electron-donor capacity of phenolic moieties in DOM. On the other hand, a critic content is observed with FA (0.70mg/g) and HA (0.65mg/g). Before reaching the critic content, the removal of phenanthrene is accelerated; while after that, the photodegradation rate is suppressed. The acceleration of phenanthrene degradation can be attributed to the photosensitization of FA and HA. Due to the strong interaction between phenanthrene and the phenyl rings, however, the retention of phenanthrene on SOM-Fe(III)-smectite in the presence of high content of HA or FA is enhanced, thus slowing down its photodegradation. Those observations provide valuable insights into the transformation and fate of PAHs in the natural soil environment and open a window for using clay-humic substances complexes for remediation of contaminated soil. Copyright © 2013 Elsevier B.V. All rights reserved.

Neuroticism, depressive symptoms and white-matter integrity in the Lothian Birth Cohort 1936.

PubMed

McIntosh, A M; Bastin, M E; Luciano, M; Maniega, S Muñoz; Del C Valdés Hernández, M; Royle, N A; Hall, J; Murray, C; Lawrie, S M; Starr, J M; Wardlaw, J M; Deary, I J

2013-06-01

Clinical depression is associated with reductions in white-matter integrity in several long tracts of the brain. The extent to which these findings are localized or related to depressive symptoms or personality traits linked to disease risk remains unclear. Method Members of the Lothian Birth Cohort 1936 (LBC936) were assessed in two waves at mean ages of 70 and 73 years. At wave 1, they underwent assessments of depressive symptoms and the personality traits of neuroticism and extraversion. Brain diffusion magnetic resonance imaging (MRI) data were obtained at the second wave and mood assessments were repeated. We tested whether depressive symptoms were related to reduced white-matter tract fractional anisotropy (FA), a measure of integrity, and then examined whether high neuroticism or low extraversion mediated this relationship. Six hundred and sixty-eight participants provided useable data. Bilateral uncinate fasciculus FA was significantly negatively associated with depressive symptoms at both waves (standardized β=0.12-0.16). Higher neuroticism and lower extraversion were also significantly associated with lower uncinate FA bilaterally (standardized β=0.09-0.15) and significantly mediated the relationship between FA and depressive symptoms. Trait liability to depression and depressive symptoms are associated with reduced structural connectivity in tracts connecting the prefrontal cortex with the amygdala and anterior temporal cortex. These effects suggest that frontotemporal disconnection is linked to the etiology of depression, in part through personality trait differences.

White matter properties differ in 6-year old Readers and Pre-Readers

PubMed Central

Kovachy, Vanessa N; Ben-Shachar, Michal; Feldman, Heidi M

2016-01-01

Reading, an essential life skill in modern society, is typically learned during childhood. Adults who can read show white matter differences compared to adults who never learned to read. Studies have not established whether children who can read show similar white matter differences compared to children who cannot read. We compared 6-year old children who could decode written English words and pseudowords (n=31; Readers) and 6-year old children who could not decode pseudowords and had a standard score < 100 on a task for reading single words (n=11; Pre-Readers). We employed diffusion MRI and tractography to extract fractional anisotropy (FA) along the trajectory of 6 bilateral intra-hemispheric tracts and 2 posterior subdivisions of the corpus callosum. Readers demonstrated significantly increased FA within the left anterior segment of the superior longitudinal fasciculus (aSLF-L) and the right uncinate fasciculus (UF-R) compared to Pre-Readers. FA in the aSLF-L was significantly correlated with phonological awareness; FA in the UF-R was significantly correlated with language. Correlations in the UF-R but not the aSLF-L remained significant after controlling for reading ability, revealing that UF-R group differences were related to both children's language and reading abilities. Taken together, these findings demonstrate new evidence showing that individual differences in white matter structure relate to whether children have begun to read. PMID:27631434

Changes in freezing tolerance, plasma membrane H+-ATPase activity and fatty acid composition in Pinus resinosa needles during cold acclimation and de-acclimation.

PubMed

Martz, Françoise; Sutinen, Marja-Liisa; Kiviniemi, Sari; Palta, Jiwan P

2006-06-01

It has previously been suggested that plasma membrane ATPase (PM H+-ATPase, EC 3.6.1.3.) is a site of incipient freezing injury because activity increases following cold acclimation and there are published data indicating that activity of PM H+-ATPase is modulated by changes in lipids associated with the enzyme. To test and extend these findings in a tree species, we analyzed PM H+-ATPase activity and the fatty acid (FA) composition of glycerolipids in purified plasma membranes (PMs) prepared by the two-phase partition method from current-year needles of adult red pine (Pinus resinosa Ait.) trees. Freezing tolerance of the needles decreased from -56 degrees C in March to -9 degrees C in May, and increased from -15 degrees C in September to -148 degrees C in January. Specific activity of vanadate-sensitive PM H+-ATPase increased more than two-fold following cold acclimation, despite a concurrent increase in protein concentration. During de-acclimation, decreases in PM H+-ATPase activity and freezing tolerance were accompanied by decreases in the proportions of oleic (18:1) and linoleic (18:2) acids and increases in the proportions of palmitic (16:0) and linolenic (18:3) acids in total glycerolipids extracted from the plasma membrane fraction. This pattern of changes in PM H+-ATPase activity and the 18:1, 18:2 and 18:3 fatty acids was reversed during cold acclimation. In the PM fractions, changes in FA unsaturation, expressed as the double bond index (1 x 18:1 + 2 x 18:2 + 3 x 18:3), were closely correlated with changes in H+-ATPase specific activity (r2 = 0.995). Changes in freezing tolerance were well correlated with DBI (r2 = 0.877) and ATPase specific activity (r2 = 0.833) in the PM fraction. Total ATPase activity in microsomal fractions also closely followed changes in freezing tolerance (r2 = 0.969). We conclude that, as in herbaceous plants, simultaneous seasonal changes in PM H+-ATPase activity and fatty acid composition occur during cold acclimation and de-acclimation in an extremely winter hardy tree species under natural conditions, lending support to the hypothesis that FA-regulated PM H+-ATPase activity is involved in the cellular response underlying cold acclimation and de-acclimation.

White-matter connectivity and methylphenidate-induced changes in attentional performance according to α2A-adrenergic receptor gene polymorphisms in Korean children with attention-deficit hyperactivity disorder.

PubMed

Park, Subin; Hong, Soon-Beom; Kim, Jae-Won; Yang, Young-Hui; Park, Min-Hyeon; Kim, Boong-Nyun; Shin, Min-Sup; Yoo, Hee-Jeong; Cho, Soo-Churl

2013-01-01

The authors examined the association between the MspI C/G and DraI C/T genotypes of the α2A-adrenergic receptor gene and white-matter connectivity and attentional performance before and after medication in 53 children with attention-deficit hyperactivity disorder. Subjects who carried the T allele at the DraI polymorphism showed fewer changes in the mean commission error scores after 8 weeks of medication and decreased fractional anisotropy (FA) values in the right middle frontal cortex than subjects without the T allele. Subjects with the C allele at the MspI polymorphism showed decreased FA values in the right postcentral gyrus than subjects without.

Natural organic matter and the event horizon of mass spectrometry.

PubMed

Hertkorn, N; Frommberger, M; Witt, M; Koch, B P; Schmitt-Kopplin, Ph; Perdue, E M

2008-12-01

Soils, sediments, freshwaters, and marine waters contain natural organic matter (NOM), an exceedingly complex mixture of organic compounds that collectively exhibit a nearly continuous range of properties (size-reactivity continuum). NOM is composed mainly of carbon, hydrogen, and oxygen, with minor contributions from heteroatoms such as nitrogen, sulfur, and phosphorus. Suwannee River fulvic acid (SuwFA) is a fraction of NOM that is relatively depleted in heteroatoms. Ultrahigh resolution Fourier transform ion cyclotron (FTICR) mass spectra of SuwFA reveal several thousand molecular formulas, corresponding in turn to several hundred thousand distinct chemical environments of carbon even without accountancy of isomers. The mass difference deltam among adjoining C,H,O-molecules between and within clusters of nominal mass is inversely related to molecular dissimilarity: any decrease of deltam imposes an ever growing mandatory difference in molecular composition. Molecular formulas that are expected for likely biochemical precursor molecules are notably absent from these spectra, indicating that SuwFA is the product of diagenetic reactions that have altered the major components of biomass beyond the point of recognition. The degree of complexity of SuwFA can be brought into sharp focus through comparison with the theoretical limits of chemical complexity, as constrained and quantized by the fundamentals of chemical binding. The theoretical C,H,O-compositional space denotes the isomer-filtered complement of the entire, very vast space of molecular structures composed solely of carbon, hydrogen, and oxygen. The molecular formulas within SuwFA occupy a sizable proportion of the theoretical C,H,O-compositional space. A 100 percent coverage of the theoretically feasible C,H,O-compositional space by SuwFA molecules is attained throughout a sizable range of mass and H/C and O/C elemental ratios. The substantial differences between (and complementarity of) the SuwFA molecular formulas that are observed using six different modes of ionization (APCI, APPI, and ESI in positive and negative modus) imply considerable selectivity of the ionization process and suggest that the observed mass spectra represent simplified projections of still more complex mixtures.

Diffusion tensor imaging can be used to detect lesions in peripheral nerves in patients with chronic inflammatory demyelinating polyneuropathy treated with subcutaneous immunoglobulin.

PubMed

Markvardsen, Lars H; Vaeggemose, Michael; Ringgaard, Steffen; Andersen, Henning

2016-08-01

Magnetic resonance imaging (MRI) with diffusion tensor imaging (DTI) has shown that fractional anisotropy (FA) is lower in peripheral nerves in chronic inflammatory demyelinating polyneuropathy (CIDP). We examined whether DTI correlates to muscle strength or impairment. MRI of sciatic and tibial nerves was performed on 3-T MR scanner by obtaining T2- and DTI-weighted sequences with fat saturation. On each slice of T2-weighted (T2w) and DTI, the tibial and sciatic nerves were segmented and served for calculation of signal intensity. On DTI images, pixel-by-pixel calculation of FA and apparent diffusion coefficient (ADC) was done. Muscle strength at knee and ankle was determined by isokinetic dynamometry and severity of CIDP by neuropathy impairment score (NIS). Fourteen CIDP patients treated with subcutaneous immunoglobulin were compared to gender- and age-matched controls. T2w values expressed as a nerve/muscle ratio (nT2w) were unchanged in CIDP versus controls 0.93 ± 0.21 versus 1.02 ± 0.21 (P = 0.10). FA values were lower in CIDP compared to controls 0.38 ± 0.07 versus 0.45 ± 0.05 (P < 0.0001), and ADC values were higher in CIDP versus controls 1735 ± 232 versus 1593 ± 116 × 10(-6) mm(2)/s (P = 0.005). In CIDP, FA values correlated to clinical impairment (NIS) (r = -0.57, P = 0.03), but not to muscle strength. FA value in the sciatic nerve distinguishes CIDP from controls with a sensitivity and a specificity of 92.9 %. CIDP patients have unchanged nT2w values, lower FA values, and higher ADC values of sciatic and tibial nerves compared to controls. FA values correlated to NIS but were unrelated to muscle strength. DTI of sciatic nerves seems promising to differentiate CIDP from controls.

Right arcuate fasciculus abnormality in chronic fatigue syndrome.

PubMed

Zeineh, Michael M; Kang, James; Atlas, Scott W; Raman, Mira M; Reiss, Allan L; Norris, Jane L; Valencia, Ian; Montoya, Jose G

2015-02-01

To identify whether patients with chronic fatigue syndrome (CFS) have differences in gross brain structure, microscopic structure, or brain perfusion that may explain their symptoms. Fifteen patients with CFS were identified by means of retrospective review with an institutional review board-approved waiver of consent and waiver of authorization. Fourteen age- and sex-matched control subjects provided informed consent in accordance with the institutional review board and HIPAA. All subjects underwent 3.0-T volumetric T1-weighted magnetic resonance (MR) imaging, with two diffusion-tensor imaging (DTI) acquisitions and arterial spin labeling (ASL). Open source software was used to segment supratentorial gray and white matter and cerebrospinal fluid to compare gray and white matter volumes and cortical thickness. DTI data were processed with automated fiber quantification, which was used to compare piecewise fractional anisotropy (FA) along 20 tracks. For the volumetric analysis, a regression was performed to account for differences in age, handedness, and total intracranial volume, and for the DTI, FA was compared piecewise along tracks by using an unpaired t test. The open source software segmentation was used to compare cerebral blood flow as measured with ASL. In the CFS population, FA was increased in the right arcuate fasciculus (P = .0015), and in right-handers, FA was also increased in the right inferior longitudinal fasciculus (ILF) (P = .0008). In patients with CFS, right anterior arcuate FA increased with disease severity (r = 0.649, P = .026). Bilateral white matter volumes were reduced in CFS (mean ± standard deviation, 467 581 mm(3) ± 47 610 for patients vs 504 864 mm(3) ± 68 126 for control subjects, P = .0026), and cortical thickness increased in both right arcuate end points, the middle temporal (T = 4.25) and precentral (T = 6.47) gyri, and one right ILF end point, the occipital lobe (T = 5.36). ASL showed no significant differences. Bilateral white matter atrophy is present in CFS. No differences in perfusion were noted. Right hemispheric increased FA may reflect degeneration of crossing fibers or strengthening of short-range fibers. Right anterior arcuate FA may serve as a biomarker for CFS. (©) RSNA, 2014.

A novel measure of reliability in Diffusion Tensor Imaging after data rejections due to subject motion.

PubMed

Sairanen, V; Kuusela, L; Sipilä, O; Savolainen, S; Vanhatalo, S

2017-02-15

Diffusion Tensor Imaging (DTI) is commonly challenged by subject motion during data acquisition, which often leads to corrupted image data. Currently used procedure in DTI analysis is to correct or completely reject such data before tensor estimations, however assessing the reliability and accuracy of the estimated tensor in such situations has evaded previous studies. This work aims to define the loss of data accuracy with increasing image rejections, and to define a robust method for assessing reliability of the result at voxel level. We carried out simulations of every possible sub-scheme (N=1,073,567,387) of Jones30 gradient scheme, followed by confirming the idea with MRI data from four newborn and three adult subjects. We assessed the relative error of the most commonly used tensor estimates for DTI and tractography studies, fractional anisotropy (FA) and the major orientation vector (V1), respectively. The error was estimated using two measures, the widely used electric potential (EP) criteria as well as the rotationally variant condition number (CN). Our results show that CN and EP are comparable in situations with very few rejections, but CN becomes clearly more sensitive to depicting errors when more gradient vectors and images were rejected. The error in FA and V1 was also found depend on the actual FA level in the given voxel; low actual FA levels were related to high relative errors in the FA and V1 estimates. Finally, the results were confirmed with clinical MRI data. This showed that the errors after rejections are, indeed, inhomogeneous across brain regions. The FA and V1 errors become progressively larger when moving from the thick white matter bundles towards more superficial subcortical structures. Our findings suggest that i) CN is a useful estimator of data reliability at voxel level, and ii) DTI preprocessing with data rejections leads to major challenges when assessing brain tissue with lower FA levels, such as all newborn brain, as well as the adult superficial, subcortical areas commonly traced in precise connectivity analyses between cortical regions. Copyright © 2016 Elsevier Inc. All rights reserved.

Assessment of the structural brain network reveals altered connectivity in children with unilateral cerebral palsy due to periventricular white matter lesions.

PubMed

Pannek, Kerstin; Boyd, Roslyn N; Fiori, Simona; Guzzetta, Andrea; Rose, Stephen E

2014-01-01

Cerebral palsy (CP) is a term to describe the spectrum of disorders of impaired motor and sensory function caused by a brain lesion occurring early during development. Diffusion MRI and tractography have been shown to be useful in the study of white matter (WM) microstructure in tracts likely to be impacted by the static brain lesion. The purpose of this study was to identify WM pathways with altered connectivity in children with unilateral CP caused by periventricular white matter lesions using a whole-brain connectivity approach. Data of 50 children with unilateral CP caused by periventricular white matter lesions (5-17 years; manual ability classification system [MACS] I = 25/II = 25) and 17 children with typical development (CTD; 7-16 years) were analysed. Structural and High Angular Resolution Diffusion weighted Images (HARDI; 64 directions, b = 3000 s/mm(2)) were acquired at 3 T. Connectomes were calculated using whole-brain probabilistic tractography in combination with structural parcellation of the cortex and subcortical structures. Connections with altered fractional anisotropy (FA) in children with unilateral CP compared to CTD were identified using network-based statistics (NBS). The relationship between FA and performance of the impaired hand in bimanual tasks (Assisting Hand Assessment-AHA) was assessed in connections that showed significant differences in FA compared to CTD. FA was reduced in children with unilateral CP compared to CTD. Seven pathways, including the corticospinal, thalamocortical, and fronto-parietal association pathways were identified simultaneously in children with left and right unilateral CP. There was a positive relationship between performance of the impaired hand in bimanual tasks and FA within the cortico-spinal and thalamo-cortical pathways (r(2) = 0.16-0.44; p < 0.05). This study shows that network-based analysis of structural connectivity can identify alterations in FA in unilateral CP, and that these alterations in FA are related to clinical function. Application of this connectome-based analysis to investigate alterations in connectivity following treatment may elucidate the neurological correlates of improved functioning due to intervention.

Fractional absorption of active absorbable algal calcium (AAACa) and calcium carbonate measured by a dual stable-isotope method

USDA-ARS?s Scientific Manuscript database

With the use of stable isotopes, this study aimed to compare the bioavailability of active absorbable algal calcium (AAACa), obtained from oyster shell powder heated to a high temperature, with an additional heated seaweed component (Heated Algal Ingredient, HAI), with that of calcium carbonate. In ...

Evaluation of neuraminidase enzyme assays using different substrates to measure susceptibility of influenza virus clinical isolates to neuraminidase inhibitors: report of the neuraminidase inhibitor susceptibility network.

PubMed

Wetherall, N T; Trivedi, T; Zeller, J; Hodges-Savola, C; McKimm-Breschkin, J L; Zambon, M; Hayden, F G

2003-02-01

The increasing use of influenza virus neuraminidase (NA) inhibitors (NIs) necessitates the development of reliable methods for assessing the NI susceptibility of clinical isolates. We evaluated three NA inhibition assays against a panel of five clinical isolates each of influenza virus A/H1N1, A/H3N2, and B strains and four viruses with a defined resistance genotype (R292K, H274Y, R152K, and E119V). For fluorometric enzyme assay (FA) 1 (FA-1), 2'-(4-methylumbelliferyl)-alpha-D-N-acetylneuraminic acid (MUNANA) at 100 microM was used as the substrate, with pretitration of the virus input. For FA-2, MUNANA at 200 microM was used as the substrate, with a fixed 1:10 dilution of input virus. For the chemiluminescence (CL) assay, the 1,2-dioxetane derivative of sialic acid at 100 microM was used as the substrate, with pretitration of the virus. Four different operators repeated the assays several times in a blinded fashion with both zanamivir and oseltamivir carboxylate (GS4071) to determine intra- and interassay variations. Mean 50% inhibitory concentration (IC(50)) values were lower and generally less variable with the CL assay. FA-1 displayed greater variation than the CL assay or FA-2 and the highest IC(50) values with zanamivir; FA-2 showed the highest values with oseltamivir, particularly for influenza virus B, and was more variable with zanamivir than was the CL assay. All three assays detected 40-fold or greater changes in IC(50) values for the resistant viruses with at least one drug. Mixing experiments, whereby increasing fractions (0, 20, 40, 60, 80, and 100%) of NA from a known NI-resistant virus were mixed with the corresponding NI-sensitive parental NA, indicated that the resolution of IC(50) values was clearer with the CL assay than with FA-2 for two of the resistant variants (R152K and E119V). The FA and CL methods were reliable for the detection of NI resistance, but all assays have certain limitations. Based on reproducibility, ease of automation, time required for the assay, and greater sensitivity, the CL assay was selected for future susceptibility testing of influenza virus isolates circulating globally.

Effects of Surgery and Proton Therapy on Cerebral White Matter of Craniopharyngioma Patients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uh, Jinsoo, E-mail: jinsoo.uh@stjude.org; Merchant, Thomas E.; Li, Yimei

Purpose: The purpose of this study was to determine radiation dose effect on the structural integrity of cerebral white matter in craniopharyngioma patients receiving surgery and proton therapy. Methods and Materials: Fifty-one patients (2.1-19.3 years of age) with craniopharyngioma underwent surgery and proton therapy in a prospective therapeutic trial. Anatomical magnetic resonance images acquired after surgery but before proton therapy were inspected to identify white matter structures intersected by surgical corridors and catheter tracks. Longitudinal diffusion tensor imaging (DTI) was performed to measure microstructural integrity changes in cerebral white matter. Fractional anisotropy (FA) derived from DTI was statistically analyzed for 51more » atlas-based white matter structures of the brain to determine radiation dose effect. FA in surgery-affected regions in the corpus callosum was compared to that in its intact counterpart to determine whether surgical defects affect radiation dose effect. Results: Surgical defects were seen most frequently in the corpus callosum because of transcallosal resection of tumors and insertion of ventricular or cyst catheters. Longitudinal DTI data indicated reductions in FA 3 months after therapy, which was followed by a recovery in most white matter structures. A greater FA reduction was correlated with a higher radiation dose in 20 white matter structures, indicating a radiation dose effect. The average FA in the surgery-affected regions before proton therapy was smaller (P=.0001) than that in their non–surgery-affected counterparts with more intensified subsequent reduction of FA (P=.0083) after therapy, suggesting that surgery accentuated the radiation dose effect. Conclusions: DTI data suggest that mild radiation dose effects occur in patients with craniopharyngioma receiving surgery and proton therapy. Surgical defects present at the time of proton therapy appear to accentuate the radiation dose effect longitudinally. This study supports consideration of pre-existing surgical defects and their locations in proton therapy planning and studies of treatment effect.« less

Reduced white matter integrity and facial emotion perception in never-medicated patients with first-episode schizophrenia: A diffusion tensor imaging study.

PubMed

Zhao, Xiaoxin; Sui, Yuxiu; Yao, Jingjing; Lv, Yiding; Zhang, Xinyue; Jin, Zhuma; Chen, Lijun; Zhang, Xiangrong

2017-07-03

Facial emotion perception is impaired in schizophrenia. Although the pathology of schizophrenia is thought to involve abnormality in white matter (WM), few studies have examined the correlation between facial emotion perception and WM abnormalities in never-medicated patients with first-episode schizophrenia. The present study tested associations between facial emotion perception and WM integrity in order to investigate the neural basis of impaired facial emotion perception in schizophrenia. Sixty-three schizophrenic patients and thirty control subjects underwent facial emotion categorization (FEC). The FEC data was inserted into a logistic function model with subsequent analysis by independent-samples T test and the shift point and slope as outcome measurements. Severity of symptoms was measured using a five-factor model of the Positive and Negative Syndrome Scale (PANSS). Voxelwise group comparison of WM fractional anisotropy (FA) was operated using tract-based spatial statistics (TBSS). The correlation between impaired facial emotion perception and FA reduction was examined in patients using simple regression analysis within brain areas that showed a significant FA reduction in patients compared with controls. The same correlation analysis was also performed for control subjects in the whole brain. The patients with schizophrenia reported a higher shift point and a steeper slope than control subjects in FEC. The patients showed a significant FA reduction in left deep WM in the parietal, temporal and occipital lobes, a small portion of the corpus callosum (CC), and the corona radiata. In voxelwise correlation analysis, we found that facial emotion perception significantly correlated with reduced FA in various WM regions, including left forceps major (FM), inferior longitudinal fasciculus (ILF), inferior fronto-occipital fasciculus (IFOF), Left splenium of CC, and left ILF. The correlation analyses in healthy controls revealed no significant correlation of FA with FEC task. These results showed disrupted WM integrity in these regions constitutes a potential neural basis for the facial emotion perception impairments in schizophrenia. Copyright © 2017 Elsevier Inc. All rights reserved.

Oxygen and Perfusion Kinetics in Response to Fractionated Radiation Therapy in FaDu Head and Neck Cancer Xenografts Are Related to Treatment Outcome

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Fangyao; Vishwanath, Karthik; Salama, Joseph K.

Purpose: To test whether oxygenation kinetics correlate with the likelihood for local tumor control after fractionated radiation therapy. Methods and Materials: We used diffuse reflectance spectroscopy to noninvasively measure tumor vascular oxygenation and total hemoglobin concentration associated with radiation therapy of 5 daily fractions (7.5, 9, or 13.5 Gy/d) in FaDu xenografts. Spectroscopy measurements were obtained immediately before each daily radiation fraction and during the week after radiation therapy. Oxygen saturation and total hemoglobin concentration were computed using an inverse Monte Carlo model. Results: First, oxygenation kinetics during and after radiation therapy, but before tumor volumes changed, were associated with localmore » tumor control. Locally controlled tumors exhibited significantly faster increases in oxygenation after radiation therapy (days 12-15) compared with tumors that recurred locally. Second, within the group of tumors that recurred, faster increases in oxygenation during radiation therapy (day 3-5 interval) were correlated with earlier recurrence times. An area of 0.74 under the receiver operating characteristic curve was achieved when classifying the local control tumors from all irradiated tumors using the oxygen kinetics with a logistic regression model. Third, the rate of increase in oxygenation was radiation dose dependent. Radiation doses ≤9.5 Gy/d did not initiate an increase in oxygenation, whereas 13.5 Gy/d triggered significant increases in oxygenation during and after radiation therapy. Conclusions: Additional confirmation is required in other tumor models, but these results suggest that monitoring tumor oxygenation kinetics could aid in the prediction of local tumor control after radiation therapy.« less

Detection of the pedogenic magnetic fraction in volcanic soils developed on basalts using frequency-dependent magnetic susceptibility: comparison of two instruments

NASA Astrophysics Data System (ADS)

Grison, Hana; Petrovsky, Eduard; Kapicka, Ales; Hanzlikova, Hana

2017-05-01

In studies of the magnetic properties of soils, the frequency-dependent magnetic susceptibility percentage (χFD%) is often used for the identification of ultrafine magnetically superparamagnetic/stable single-domain (SP/SSD) particles. This parameter is commonly used as an indicator for increased pedogenesis. In strongly magnetic soils, the SP/SSD magnetic signal (mostly bio-pedogenic) may be masked by lithological signals; making pedogenesis hard to detect. In this study, we compare results for the detection of ultrafine SP/SSD magnetic particles in andic soils using two instruments: a Bartington MS2B dual-frequency meter and an AGICO Kappabridge MFK1-FA. In particular, the study focuses on the effect of pedogenesis by investigating the relationship between specific soil magnetic and chemical properties (soil organic carbon and pHH2O). The values of χFD% obtained with the MS2B varied from 2.4 to 5.9 per cent, and mass-specific magnetic susceptibility (χLF) from 283 to 1688 × 10-8 m3 kg-1, while values of χFD% and χLF obtained with the MFK1-FA varied from 2.7 to 8.2 per cent and from 299 to 1859 × 10-8 m3 kg-1, respectively. Our results suggest that the detection of the SP/SSD magnetic fraction can be accomplished by comparing relative trends of χFD% along the soil profile. Moreover, the discrimination between bio-pedogenic and lithogenic magnetic contributions in the SP/SSD fraction is possible by comparing the χFD% and χLF data determined in the fine earth (<2 mm) and the coarse fraction (4-10 mm) samples down the soil profile.

Atmospheric histories and global emissions of the anthropogenic hydrofluorocarbons HFC-365mfc, HFC-245fa, HFC-227ea, and HFC-236fa

NASA Astrophysics Data System (ADS)

Vollmer, Martin K.; Miller, Benjamin R.; Rigby, Matthew; Reimann, Stefan; Mühle, Jens; Krummel, Paul B.; O'Doherty, Simon; Kim, Jooil; Rhee, Tae Siek; Weiss, Ray F.; Fraser, Paul J.; Simmonds, Peter G.; Salameh, Peter K.; Harth, Christina M.; Wang, Ray H. J.; Steele, L. Paul; Young, Dickon; Lunder, Chris R.; Hermansen, Ove; Ivy, Diane; Arnold, Tim; Schmidbauer, Norbert; Kim, Kyung-Ryul; Greally, Brian R.; Hill, Matthias; Leist, Michael; Wenger, Angelina; Prinn, Ronald G.

2011-04-01

We report on ground-based atmospheric measurements and emission estimates of the four anthropogenic hydrofluorocarbons (HFCs) HFC-365mfc (CH3CF2CH2CF3, 1,1,1,3,3-pentafluorobutane), HFC-245fa (CHF2CH2CF3, 1,1,1,3,3-pentafluoropropane), HFC-227ea (CF3CHFCF3, 1,1,1,2,3,3,3-heptafluoropropane), and HFC-236fa (CF3CH2CF3, 1,1,1,3,3,3-hexafluoropropane). In situ measurements are from the global monitoring sites of the Advanced Global Atmospheric Gases Experiment (AGAGE), the System for Observations of Halogenated Greenhouse Gases in Europe (SOGE), and Gosan (South Korea). We include the first halocarbon flask sample measurements from the Antarctic research stations King Sejong and Troll. We also present measurements of archived air samples from both hemispheres back to the 1970s. We use a two-dimensional atmospheric transport model to simulate global atmospheric abundances and to estimate global emissions. HFC-365mfc and HFC-245fa first appeared in the atmosphere only ˜1 decade ago; they have grown rapidly to globally averaged dry air mole fractions of 0.53 ppt (in parts per trillion, 10-12) and 1.1 ppt, respectively, by the end of 2010. In contrast, HFC-227ea first appeared in the global atmosphere in the 1980s and has since grown to ˜0.58 ppt. We report the first measurements of HFC-236fa in the atmosphere. This long-lived compound was present in the atmosphere at only 0.074 ppt in 2010. All four substances exhibit yearly growth rates of >8% yr-1 at the end of 2010. We find rapidly increasing emissions for the foam-blowing compounds HFC-365mfc and HFC-245fa starting in ˜2002. After peaking in 2006 (HFC-365mfc: 3.2 kt yr-1, HFC-245fa: 6.5 kt yr-1), emissions began to decline. Our results for these two compounds suggest that recent estimates from long-term projections (to the late 21st century) have strongly overestimated emissions for the early years of the projections (˜2005-2010). Global HFC-227ea and HFC-236fa emissions have grown to average values of 2.4 kt yr-1 and 0.18 kt yr-1 over the 2008-2010 period, respectively.

Z-scan Measurement of Upconversion in Er:YAG

DTIC Science & Technology

2010-12-01

of each manifold, e.g.   22414313212121 NCWNWNWNNfNfh I td Nd upae    . (1) Here, N1 (N2) is the population of the 4I15/2 (4I13/2...manifold, I is the laser intensity,  is the absolute cross section, fa ( fe ) is the probability that an ion in the 4I15/2 (4I13/2) manifold is in a...sublevel that can absorb (emit) a laser photon, Wij is the relaxation rate from level i to level j, and Cup is the upconversion coefficient. Also

Bias in the Wagner-Nelson estimate of the fraction of drug absorbed.

PubMed

Wang, Yibin; Nedelman, Jerry

2002-04-01

To examine and quantify bias in the Wagner-Nelson estimate of the fraction of drug absorbed resulting from the estimation error of the elimination rate constant (k), measurement error of the drug concentration, and the truncation error in the area under the curve. Bias in the Wagner-Nelson estimate was derived as a function of post-dosing time (t), k, ratio of absorption rate constant to k (r), and the coefficient of variation for estimates of k (CVk), or CV% for the observed concentration, by assuming a one-compartment model and using an independent estimate of k. The derived functions were used for evaluating the bias with r = 0.5, 3, or 6; k = 0.1 or 0.2; CV, = 0.2 or 0.4; and CV, =0.2 or 0.4; for t = 0 to 30 or 60. Estimation error of k resulted in an upward bias in the Wagner-Nelson estimate that could lead to the estimate of the fraction absorbed being greater than unity. The bias resulting from the estimation error of k inflates the fraction of absorption vs. time profiles mainly in the early post-dosing period. The magnitude of the bias in the Wagner-Nelson estimate resulting from estimation error of k was mainly determined by CV,. The bias in the Wagner-Nelson estimate resulting from to estimation error in k can be dramatically reduced by use of the mean of several independent estimates of k, as in studies for development of an in vivo-in vitro correlation. The truncation error in the area under the curve can introduce a negative bias in the Wagner-Nelson estimate. This can partially offset the bias resulting from estimation error of k in the early post-dosing period. Measurement error of concentration does not introduce bias in the Wagner-Nelson estimate. Estimation error of k results in an upward bias in the Wagner-Nelson estimate, mainly in the early drug absorption phase. The truncation error in AUC can result in a downward bias, which may partially offset the upward bias due to estimation error of k in the early absorption phase. Measurement error of concentration does not introduce bias. The joint effect of estimation error of k and truncation error in AUC can result in a non-monotonic fraction-of-drug-absorbed-vs-time profile. However, only estimation error of k can lead to the Wagner-Nelson estimate of fraction of drug absorbed greater than unity.

Electron absorbed fractions of energy and S-values in an adult human skeleton based on µCT images of trabecular bone

NASA Astrophysics Data System (ADS)

Kramer, R.; Richardson, R. B.; Cassola, V. F.; Vieira, J. W.; Khoury, H. J.; Lira, C. A. B. de O.; Robson Brown, K.

2011-03-01

When the human body is exposed to ionizing radiation, among the soft tissues at risk are the active marrow (AM) and the bone endosteum (BE) located in tiny, irregular cavities of trabecular bone. Determination of absorbed fractions (AFs) of energy or absorbed dose in the AM and the BE represent one of the major challenges of dosimetry. Recently, at the Department of Nuclear Energy at the Federal University of Pernambuco, a skeletal dosimetry method based on µCT images of trabecular bone introduced into the spongiosa voxels of human phantoms has been developed and applied mainly to external exposure to photons. This study uses the same method to calculate AFs of energy and S-values (absorbed dose per unit activity) for electron-emitting radionuclides known to concentrate in skeletal tissues. The modelling of the skeletal tissue regions follows ICRP110, which defines the BE as a 50 µm thick sub-region of marrow next to the bone surfaces. The paper presents mono-energetic AFs for the AM and the BE for eight different skeletal regions for electron source energies between 1 keV and 10 MeV. The S-values are given for the beta emitters 14C, 59Fe, 131I, 89Sr, 32P and 90Y. Comparisons with results from other investigations showed good agreement provided that differences between methodologies and trabecular bone volume fractions were properly taken into account. Additionally, a comparison was made between specific AFs of energy in the BE calculated for the actual 50 µm endosteum and the previously recommended 10 µm endosteum. The increase in endosteum thickness leads to a decrease of the endosteum absorbed dose by up to 3.7 fold when bone is the source region, while absorbed dose increases by ~20% when the beta emitters are in marrow.

Shared genetic variance between obesity and white matter integrity in Mexican Americans

PubMed Central

Spieker, Elena A.; Kochunov, Peter; Rowland, Laura M.; Sprooten, Emma; Winkler, Anderson M.; Olvera, Rene L.; Almasy, Laura; Duggirala, Ravi; Fox, Peter T.; Blangero, John; Glahn, David C.; Curran, Joanne E.

2015-01-01

Obesity is a chronic metabolic disorder that may also lead to reduced white matter integrity, potentially due to shared genetic risk factors. Genetic correlation analyses were conducted in a large cohort of Mexican American families in San Antonio (N = 761, 58% females, ages 18–81 years; 41.3 ± 14.5) from the Genetics of Brain Structure and Function Study. Shared genetic variance was calculated between measures of adiposity [(body mass index (BMI; kg/m2) and waist circumference (WC; in)] and whole-brain and regional measurements of cerebral white matter integrity (fractional anisotropy). Whole-brain average and regional fractional anisotropy values for 10 major white matter tracts were calculated from high angular resolution diffusion tensor imaging data (DTI; 1.7 × 1.7 × 3 mm; 55 directions). Additive genetic factors explained intersubject variance in BMI (heritability, h2 = 0.58), WC (h2 = 0.57), and FA (h2 = 0.49). FA shared significant portions of genetic variance with BMI in the genu (ρG = −0.25), body (ρG = −0.30), and splenium (ρG = −0.26) of the corpus callosum, internal capsule (ρG = −0.29), and thalamic radiation (ρG = −0.31) (all p's = 0.043). The strongest evidence of shared variance was between BMI/WC and FA in the superior fronto-occipital fasciculus (ρG = −0.39, p = 0.020; ρG = −0.39, p = 0.030), which highlights region-specific variation in neural correlates of obesity. This may suggest that increase in obesity and reduced white matter integrity share common genetic risk factors. PMID:25763009

Increase in gray matter volume and white matter fractional anisotropy in the motor pathways of patients with secondarily generalized neocortical seizures.

PubMed

Hsin, Yue-Loong; Harnod, Tomor; Chang, Cheng-Siu; Peng, Syu-Jyun

2017-11-01

Convulsive motor activity is a clinical manifestation of secondarily generalized seizures evolving from different focal regions. The way in which the motor seizures present themselves is not very different from most of the generalized seizures in and between epilepsy patients. This might point towards the involvement of motor-related cortices and corticospinal pathway for wide spread propagation of epileptic activity. Our aim was to identify changes in the cerebral structures and to correlate clinical variables with structural changes particularly in the motor-related cortices and pathway of patients with generalized convulsions from different seizure foci. Sixteen patients with focal onset and secondarily generalized seizures were included, along with sixteen healthy volunteers. Structural differences were analysed by measuring grey matter (GM) volume and thickness via T1-weighted MRI, and white matter (WM) fractional anisotropy (FA) via diffusion tensor imaging. GM and WM microstructural properties were compared between patients and controls by voxel- and surface- based analyses. Next, morphometric findings were correlated with seizure severity and disease duration to identify the pathologic process. In addition to widely reduced GM and WM properties, increased GM volume in the bilateral precentral gyri and paracentral lobules, and elevated regional FA in the bilateral corticospinal tracts adjacent to these motor -related GM were observed in patients and with higher statistical difference in the sub-patient group with drug-resistance. The increment of GM volume and WM FA in the motor pathway positively correlated with severity and duration of epilepsy. The demonstrated microstructural changes of motor pathways imply a plastic process of motor networks in the patients with frequent generalization of focal seizures. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Unification of X-ray Winds in Seyfert Galaxies: From Ultra-fast Outflows to Warm Absorbers

NASA Astrophysics Data System (ADS)

Tombesi, Francesco; Cappi, M.; Reeves, J.; Nemmen, R.; Braito, V.; Gaspari, M.; Reynolds, C. S.

2013-04-01

The existence of ionized X-ray absorbing layers of gas along the line of sight to the nuclei of Seyfert galaxies is a well established observational fact. This material is systematically outflowing and shows a large range in parameters. However, its actual nature and dynamics are still not clear. In order to gain insights into these important issues we performed a literature search for papers reporting the parameters of the soft X-ray warm absorbers (WAs) in 35 type 1 Seyferts and compared their properties to those of the ultra-fast outflows (UFOs) detected in the same sample. The fraction of sources with WAs is >60%, consistent with previous studies. The fraction of sources with UFOs is >34%, >67% of which also show WAs. The large dynamic range obtained when considering all the absorbers together allows us, for the first time, to investigate general relations among them. In particular, we find significant correlations indicating that the closer the absorber is to the central black hole, the higher the ionization, column, outflow velocity and consequently the mechanical power. The absorbers continuously populate the whole parameter space, with the WAs and the UFOs lying always at the two ends of the distribution. This strongly suggest that these absorbers, often considered of different types, could actually represent parts of a single large-scale stratified outflow observed at different locations from the black hole. The observed parameters and correlations are consistent with both radiation pressure through Compton scattering and MHD processes contributing to the outflow acceleration, the latter playing a major role. Most of the absorbers, especially the UFOs, have a sufficiently high mechanical power to significantly contribute to the AGN feedback.

Glial activation colocalizes with structural abnormalities in amyotrophic lateral sclerosis.

PubMed

Alshikho, Mohamad J; Zürcher, Nicole R; Loggia, Marco L; Cernasov, Paul; Chonde, Daniel B; Izquierdo Garcia, David; Yasek, Julia E; Akeju, Oluwaseun; Catana, Ciprian; Rosen, Bruce R; Cudkowicz, Merit E; Hooker, Jacob M; Atassi, Nazem

2016-12-13

In this cross-sectional study, we aimed to evaluate brain structural abnormalities in relation to glial activation in the same cohort of participants. Ten individuals with amyotrophic lateral sclerosis (ALS) and 10 matched healthy controls underwent brain imaging using integrated MR/PET and the radioligand [ 11 C]-PBR28. Diagnosis history and clinical assessments including Upper Motor Neuron Burden Scale (UMNB) were obtained from patients with ALS. Diffusion tensor imaging (DTI) analyses including tract-based spatial statistics and tractography were applied. DTI metrics including fractional anisotropy (FA) and diffusivities (mean, axial, and radial) were measured in regions of interest. Cortical thickness was assessed using surface-based analysis. The locations of structural changes, measured by DTI and the areas of cortical thinning, were compared to regional glial activation measured by relative [ 11 C]-PBR28 uptake. In this cohort of individuals with ALS, reduced FA and cortical thinning colocalized with regions demonstrating higher radioligand binding. [ 11 C]-PBR28 binding in the left motor cortex was correlated with FA (r = -0.68, p < 0.05) and cortical thickness (r = -0.75, p < 0.05). UMNB was correlated with glial activation (r = +0.75, p < 0.05), FA (r = -0.77, p < 0.05), and cortical thickness (r = -0.75, p < 0.05) in the motor cortex. Increased uptake of the glial marker [ 11 C]-PBR28 colocalizes with changes in FA and cortical thinning. This suggests a link between disease mechanisms (gliosis and inflammation) and structural changes (cortical thinning and white and gray matter changes). In this multimodal neuroimaging work, we provide an in vivo model to investigate the pathogenesis of ALS. © 2016 American Academy of Neurology.

Glial activation colocalizes with structural abnormalities in amyotrophic lateral sclerosis

PubMed Central

Alshikho, Mohamad J.; Zürcher, Nicole R.; Loggia, Marco L.; Cernasov, Paul; Chonde, Daniel B.; Izquierdo Garcia, David; Yasek, Julia E.; Akeju, Oluwaseun; Catana, Ciprian; Rosen, Bruce R.; Cudkowicz, Merit E.

2016-01-01

Objective: In this cross-sectional study, we aimed to evaluate brain structural abnormalities in relation to glial activation in the same cohort of participants. Methods: Ten individuals with amyotrophic lateral sclerosis (ALS) and 10 matched healthy controls underwent brain imaging using integrated MR/PET and the radioligand [11C]-PBR28. Diagnosis history and clinical assessments including Upper Motor Neuron Burden Scale (UMNB) were obtained from patients with ALS. Diffusion tensor imaging (DTI) analyses including tract-based spatial statistics and tractography were applied. DTI metrics including fractional anisotropy (FA) and diffusivities (mean, axial, and radial) were measured in regions of interest. Cortical thickness was assessed using surface-based analysis. The locations of structural changes, measured by DTI and the areas of cortical thinning, were compared to regional glial activation measured by relative [11C]-PBR28 uptake. Results: In this cohort of individuals with ALS, reduced FA and cortical thinning colocalized with regions demonstrating higher radioligand binding. [11C]-PBR28 binding in the left motor cortex was correlated with FA (r = −0.68, p < 0.05) and cortical thickness (r = −0.75, p < 0.05). UMNB was correlated with glial activation (r = +0.75, p < 0.05), FA (r = −0.77, p < 0.05), and cortical thickness (r = −0.75, p < 0.05) in the motor cortex. Conclusions: Increased uptake of the glial marker [11C]-PBR28 colocalizes with changes in FA and cortical thinning. This suggests a link between disease mechanisms (gliosis and inflammation) and structural changes (cortical thinning and white and gray matter changes). In this multimodal neuroimaging work, we provide an in vivo model to investigate the pathogenesis of ALS. PMID:27837005

Assessment of white matter abnormalities in paranoid schizophrenia and bipolar mania patients.

PubMed

Cui, Liqian; Chen, Zhuangfei; Deng, Wei; Huang, Xiaoqi; Li, Mingli; Ma, Xiaohong; Huang, Chaohua; Jiang, Lijun; Wang, Yingcheng; Wang, Qiang; Collier, David A; Gong, Qiyong; Li, Tao

2011-12-30

White matter abnormalities have been repeatedly reported in both schizophrenia and bipolar disorder (BD) in diffusion tensor imaging (DTI) studies, but the empirical evidence about the diagnostic specificity of white matter abnormalities in these disorders is still limited. This study sought to investigate the alterations in fractional anisotropy (FA) in white matter throughout the entire brain of patients from Chengdu, China with paranoid schizophrenia and bipolar mania. For this purpose, DTI was used to assess white matter integrity in patients with paranoid schizophrenia (n=25) and psychotic bipolar mania (n=18) who had been treated with standard pharmacotherapy for fewer than 5 days at the time of study, as well as in normal controls (n=30). The differences in FA were measured by use of voxel-based analysis. The results show that reduced FA was found in the left posterior corona radiata (PCR) in patients with psychotic bipolar mania and paranoid schizophrenia compared to the controls. Patients with psychotic bipolar mania also showed a significant reduction in FA in right posterior corona radiata and in right anterior thalamic radiation (ATR). A direct comparison between the two patient groups found no significant differences in any regions, and none of the findings were associated with illness duration. Correlation analysis indicated that FA values showed a significant negative correlation with positive symptom scores on the Positive and Negative Syndrome Scale in the left frontal-parietal lobe in the paranoid schizophrenia. It was concluded that common abnormalities in the left PCR might imply an overlap in white matter pathology in the two disorders and might be related to shared risk factors for the two disorders. 2011 Elsevier Ireland Ltd. All rights reserved.

The importance of group-wise registration in tract based spatial statistics study of neurodegeneration: a simulation study in Alzheimer's disease.

PubMed

Keihaninejad, Shiva; Ryan, Natalie S; Malone, Ian B; Modat, Marc; Cash, David; Ridgway, Gerard R; Zhang, Hui; Fox, Nick C; Ourselin, Sebastien

2012-01-01

Tract-based spatial statistics (TBSS) is a popular method for the analysis of diffusion tensor imaging data. TBSS focuses on differences in white matter voxels with high fractional anisotropy (FA), representing the major fibre tracts, through registering all subjects to a common reference and the creation of a FA skeleton. This work considers the effect of choice of reference in the TBSS pipeline, which can be a standard template, an individual subject from the study, a study-specific template or a group-wise average. While TBSS attempts to overcome registration error by searching the neighbourhood perpendicular to the FA skeleton for the voxel with maximum FA, this projection step may not compensate for large registration errors that might occur in the presence of pathology such as atrophy in neurodegenerative diseases. This makes registration performance and choice of reference an important issue. Substantial work in the field of computational anatomy has shown the use of group-wise averages to reduce biases while avoiding the arbitrary selection of a single individual. Here, we demonstrate the impact of the choice of reference on: (a) specificity (b) sensitivity in a simulation study and (c) a real-world comparison of Alzheimer's disease patients to controls. In (a) and (b), simulated deformations and decreases in FA were applied to control subjects to simulate changes of shape and WM integrity similar to what would be seen in AD patients, in order to provide a "ground truth" for evaluating the various methods of TBSS reference. Using a group-wise average atlas as the reference outperformed other references in the TBSS pipeline in all evaluations.

Structural and Diffusion Property Alterations in Unaffected Siblings of Patients with Obsessive-Compulsive Disorder

PubMed Central

Shi, Changzheng; Miao, Guodong; Yang, Qiong; Gao, Wei; Wolff, Jason J.; Chan, Raymond C. K.; Shen, Dinggang

2014-01-01

Disrupted white matter integrity and abnormal cortical thickness are widely reported in the pathophysiology of obsessive-compulsive disorder (OCD). However, the relationship between alterations in white matter connectivity and cortical thickness in OCD is unclear. In addition, the heritability of this relationship is poorly understood. To investigate the relationship of white matter microstructure with cortical thickness, we measure fractional anisotropy (FA) of white matter in 30 OCD patients, 19 unaffected siblings and 30 matched healthy controls. Then, we take those regions of significantly altered FA in OCD patients compared with healthy controls to perform fiber tracking. Next, we calculate the fiber quantity in the same tracts. Lastly, we compare cortical thickness in the target regions of those tracts. Patients with OCD exhibited decreased FA in cingulum, arcuate fibers near the superior parietal lobule, inferior longitudinal fasciculus near the right superior temporal gyrus and uncinate fasciculus. Siblings showed reduced FA in arcuate fibers near the superior parietal lobule and anterior limb of internal capsule. Significant reductions in both fiber quantities and cortical thickness in OCD patients and their unaffected siblings were also observed in the projected brain areas when using the arcuate fibers near the left superior parietal lobule as the starting points. Reduced FA in the left superior parietal lobule was observed not only in patients with OCD but also in their unaffected siblings. Originated from the superior parietal lobule, the number of fibers was also found to be decreased and the corresponding cortical regions were thinner relative to controls. The linkage between disrupted white matter integrity and the abnormal cortical thickness may be a vulnerability marker for OCD. PMID:24489665

Multi-site genetic analysis of diffusion images and voxelwise heritability analysis: A pilot project of the ENIGMA–DTI working group

PubMed Central

Jahanshad, Neda; Kochunov, Peter; Sprooten, Emma; Mandl, René C.; Nichols, Thomas E.; Almassy, Laura; Blangero, John; Brouwer, Rachel M.; Curran, Joanne E.; de Zubicaray, Greig I.; Duggirala, Ravi; Fox, Peter T.; Hong, L. Elliot; Landman, Bennett A.; Martin, Nicholas G.; McMahon, Katie L.; Medland, Sarah E.; Mitchell, Braxton D.; Olvera, Rene L.; Peterson, Charles P.; Starr, John M.; Sussmann, Jessika E.; Toga, Arthur W.; Wardlaw, Joanna M.; Wright, Margaret J.; Hulshoff Pol, Hilleke E.; Bastin, Mark E.; McIntosh, Andrew M.; Deary, Ian J.; Thompson, Paul M.; Glahn, David C.

2013-01-01

The ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) Consortium was set up to analyze brain measures and genotypes from multiple sites across the world to improve the power to detect genetic variants that influence the brain. Diffusion tensor imaging (DTI) yields quantitative measures sensitive to brain development and degeneration, and some common genetic variants may be associated with white matter integrity or connectivity. DTI measures, such as the fractional anisotropy (FA) of water diffusion, may be useful for identifying genetic variants that influence brain microstructure. However, genome-wide association studies (GWAS) require large populations to obtain sufficient power to detect and replicate significant effects, motivating a multi-site consortium effort. As part of an ENIGMA–DTI working group, we analyzed high-resolution FA images from multiple imaging sites across North America, Australia, and Europe, to address the challenge of harmonizing imaging data collected at multiple sites. Four hundred images of healthy adults aged 18–85 from four sites were used to create a template and corresponding skeletonized FA image as a common reference space. Using twin and pedigree samples of different ethnicities, we used our common template to evaluate the heritability of tract-derived FA measures. We show that our template is reliable for integrating multiple datasets by combining results through meta-analysis and unifying the data through exploratory mega-analyses. Our results may help prioritize regions of the FA map that are consistently influenced by additive genetic factors for future genetic discovery studies. Protocols and templates are publicly available at (http://enigma.loni.ucla.edu/ongoing/dti-working-group/). PMID:23629049

Unique white matter microstructural patterns in ADHD presentations-a diffusion tensor imaging study.

PubMed

Svatkova, Alena; Nestrasil, Igor; Rudser, Kyle; Goldenring Fine, Jodene; Bledsoe, Jesse; Semrud-Clikeman, Margaret

2016-09-01

Attention-deficit/hyperactivity disorder predominantly inattentive (ADHD-PI) and combined (ADHD-C) presentations are likely distinct disorders that differ neuroanatomically, neurochemically, and neuropsychologically. However, to date, little is known about specific white matter (WM) regions differentiating ADHD presentations. This study examined differences in WM microstructure using diffusion tensor imaging (DTI) data from 20 ADHD-PI, 18 ADHD-C, and 27 typically developed children. Voxel-wise analysis of DTI measurements in major fiber bundles was carried out using tract-based spatial statistics (TBSS). Clusters showing diffusivity abnormalities were used as regions of interest for regression analysis between fractional anisotropy (FA) and neuropsychological outcomes. Compared to neurotypicals, ADHD-PI children showed higher FA in the anterior thalamic radiations (ATR), bilateral inferior longitudinal fasciculus (ILF), and in the left corticospinal tract (CST). In contrast, the ADHD-C group exhibited higher FA in the bilateral cingulum bundle (CB). In the ADHD-PI group, differences in FA in the left ILF and ATR were accompanied by axial diffusivity (AD) abnormalities. In addition, the ADHD-PI group exhibited atypical mean diffusivity in the forceps minor (FMi) and left ATR and AD differences in right CB compared to healthy subjects. Direct comparison between ADHD presentations demonstrated radial diffusivity differences in FMi. WM clusters with FA irregularities in ADHD were associated with neurobehavioral performance across groups. In conclusion, differences in WM microstructure in ADHD presentations strengthen the theory that ADHD-PI and ADHD-C are two distinct disorders. Regions with WM irregularity seen in both ADHD presentations might serve as predictors of executive and behavioral functioning across groups. Hum Brain Mapp 37:3323-3336, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

The Importance of Group-Wise Registration in Tract Based Spatial Statistics Study of Neurodegeneration: A Simulation Study in Alzheimer's Disease

PubMed Central

Keihaninejad, Shiva; Ryan, Natalie S.; Malone, Ian B.; Modat, Marc; Cash, David; Ridgway, Gerard R.; Zhang, Hui; Fox, Nick C.; Ourselin, Sebastien

2012-01-01

Tract-based spatial statistics (TBSS) is a popular method for the analysis of diffusion tensor imaging data. TBSS focuses on differences in white matter voxels with high fractional anisotropy (FA), representing the major fibre tracts, through registering all subjects to a common reference and the creation of a FA skeleton. This work considers the effect of choice of reference in the TBSS pipeline, which can be a standard template, an individual subject from the study, a study-specific template or a group-wise average. While TBSS attempts to overcome registration error by searching the neighbourhood perpendicular to the FA skeleton for the voxel with maximum FA, this projection step may not compensate for large registration errors that might occur in the presence of pathology such as atrophy in neurodegenerative diseases. This makes registration performance and choice of reference an important issue. Substantial work in the field of computational anatomy has shown the use of group-wise averages to reduce biases while avoiding the arbitrary selection of a single individual. Here, we demonstrate the impact of the choice of reference on: (a) specificity (b) sensitivity in a simulation study and (c) a real-world comparison of Alzheimer's disease patients to controls. In (a) and (b), simulated deformations and decreases in FA were applied to control subjects to simulate changes of shape and WM integrity similar to what would be seen in AD patients, in order to provide a “ground truth” for evaluating the various methods of TBSS reference. Using a group-wise average atlas as the reference outperformed other references in the TBSS pipeline in all evaluations. PMID:23139736

Testing the hypothesis of accelerated cerebral white matter aging in schizophrenia and major depression.

PubMed

Kochunov, Peter; Glahn, David C; Rowland, Laura M; Olvera, Rene L; Winkler, Anderson; Yang, Yi-Hong; Sampath, Hemalatha; Carpenter, Will T; Duggirala, Ravindranath; Curran, Joanne; Blangero, John; Hong, L Elliot

2013-03-01

Elevated rate of aging-related biological and functional decline, termed "accelerated aging," is reported in patients with schizophrenia (SCZ) and major depressive disorder (MDD). We used diffusion tensor imaging derived fractional anisotropy (FA) as a biomarker of aging-related decline in white matter (WM) integrity to test the hypotheses of accelerated aging in SCZ and MDD. The SCZ cohort comprised 58 SCZ patients and 60 controls (aged 20-60 years). The MDD cohort comprised 136 MDD patients and 351 controls (aged 20-79 years). The main outcome measures were the diagnosis-by-age interaction on whole-brain-averaged WM FA values and FA values from 12 major WM tracts. Diagnosis-by-age interaction for the whole-brain average FA was significant for the SCZ (p = .04) but not the MDD (p = .80) cohort. Diagnosis-by-age interaction was nominally significant (p<.05) for five WM tracts for SCZ and for none of the tracts in the MDD cohort. Tract-specific heterochronicity of the onset of age-related decline in SCZ demonstrated strong negative correlations with the age-of-peak myelination and the rates of age-related decline obtained from normative sample (r =-.61 and-.80, p<.05, respectively). No such trends existed for MDD cohort. Cerebral WM showed accelerated aging in SCZ but not in MDD, suggesting some difference in the pathophysiology underlying their WM aging changes. Tract-specific heterochronicity of WM development modulated presentation of accelerated aging in SCZ: WM tracts that matured later in life appeared more sensitive to the pathophysiology of SCZ and demonstrated more susceptibility to disorder-related accelerated decline in FA values with age. This trend was not observed in MDD cohort. Copyright © 2013 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Testing the hypothesis of accelerated cerebral white matter aging in schizophrenia and major depression

PubMed Central

Kochunov, P.; Glahn, D.C.; Rowland, L.M.; Olvera, R.L.; Winkler, A; Yang, Y.H.; Sampath, H.; Carpenter, W.T.; Dugarrila, R.; Curran, J.; Blangero, J.; Hong, L.E.

2012-01-01

Introduction Elevated rate of aging-related biological and functional decline, termed accelerated aging, is reported in patients with schizophrenia (SCZ) and major depressive disorder (MDD). We used diffusion tensor imaging (DTI) derived fractional anisotropy (FA) as biomarkers of aging-related decline in white matter (WM) integrity to test the hypotheses of accelerated aging in SCZ and MDD. Methods The SCZ cohort was composed of 58/60 SCZ patients/controls (age=20–60years). MDD cohort was composed of 136/351 MDD patients/controls (age=20–79years). Main outcome measures were the diagnosis-by-age interaction on whole-brain-averaged WM FA values and FA values from twelve major WM tracts. Results Diagnosis-by-age interaction for the whole-brain average FA was significant for the SCZ (p=0.04) but not in MDD cohort (p=0.80). Diagnosis-by-age interaction was nominally significant (p<0.05) for five WM tracts for SCZ and for none of the tracts in the MDD cohort. Tract-specific heterochronicity of the onset of age-related decline in SCZ demonstrated strong negative correlations with the age-of- peak myelination and the rates of age-related decline obtained from normative sample (r=−0.61 and −0.80, p<0.05, respectively). No such trends existed for MDD cohort. Conclusion Cerebral WM showed accelerated aging in SCZ but not in MDD, suggesting some difference in the pathophysiology underlying their WM aging changes. Tract-specific heterochronicity of WM development modulated presentation of accelerated aging in SCZ: white matter tracts that matured later in life appeared more sensitive to the pathophysiology of SCZ and demonstrated more susceptibility to disorder-related accelerated decline in FA values with age. This trend was not observed in MDD cohort. PMID:23200529

Subconcussive Head Impact Exposure and White Matter Tract Changes over a Single Season of Youth Football

PubMed Central

Bahrami, Naeim; Sharma, Dev; Rosenthal, Scott; Davenport, Elizabeth M.; Urban, Jillian E.; Wagner, Benjamin; Jung, Youngkyoo; Vaughan, Christopher G.; Gioia, Gerard A.; Stitzel, Joel D.; Maldjian, Joseph A.

2016-01-01

Purpose To examine the effects of subconcussive impacts resulting from a single season of youth (age range, 8–13 years) football on changes in specific white matter (WM) tracts as detected with diffusion-tensor imaging in the absence of clinically diagnosed concussions. Materials and Methods Head impact data were recorded by using the Head Impact Telemetry system and quantified as the combined-probability risk-weighted cumulative exposure (RWECP). Twenty-five male participants were evaluated for seasonal fractional anisotropy (FA) changes in specific WM tracts: the inferior fronto-occipital fasciculus (IFOF), inferior longitudinal fasciculus, and superior longitudinal fasciculus (SLF). Fiber tracts were segmented into a central core and two fiber terminals. The relationship between seasonal FA change in the whole fiber, central core, and the fiber terminals with RWECP was also investigated. Linear regression analysis was conducted to determine the association between RWECP and change in fiber tract FA during the season. Results There were statistically significant linear relationships between RWEcp and decreased FA in the whole (R2 = 0.433; P = .003), core (R2 = 0.3649; P = .007), and terminals (R2 = 0.5666; P < .001) of left IFOF. A trend toward statistical significance (P = .08) in right SLF was observed. A statistically significant correlation between decrease in FA of the right SLF terminal and RWECP was also observed (R2 = 0.2893; P = .028). Conclusion This study found a statistically significant relationship between head impact exposure and change of FAfractional anisotropy value of whole, core, and terminals of left IFOF and right SLF’s terminals where WM and gray matter intersect, in the absence of a clinically diagnosed concussion. © RSNA, 2016 PMID:27775478

Cerebellar peduncle injury predicts motor impairments in preterm infants: A quantitative tractography study at term-equivalent age.

PubMed

Hasegawa, Tatsuji; Yamada, Kei; Tozawa, Takenori; Chiyonobu, Tomohiro; Tokuda, Sachiko; Nishimura, Akira; Hosoi, Hajime; Morimoto, Masafumi

2018-05-15

Cerebellar injury is well established as an important finding in preterm infants with cerebral palsy (CP). In this study, we investigated associations between injury to the cerebellar peduncles and motor impairments in preterm infants using quantitative tractography at term-equivalent age, which represents an early phase before the onset of motor impairments. We studied 64 preterm infants who were born at <33 weeks gestational age. These infants were divided into three groups: CP, Non-CP (defined as infants with periventricular leukomalacia but having normal motor function), and a Normal group. Diffusion tensor imaging was performed at term-equivalent age and motor function was assessed no earlier than a corrected age of 2 years. Using tractography, we measured fractional anisotropy (FA) and apparent diffusion coefficient (ADC) of the superior cerebellar peduncles (SCP) and middle cerebellar peduncles (MCP), as well as the motor/sensory tracts. The infants in the CP group had significantly lower FA of the SCP and sensory tract than those in the other groups. There was no significant difference in FA and ADC of the motor tract among the three groups. Severity of CP had a significant correlation with FA of the MCP, but not with the FA of other white matter tracts. Our results suggested that the infants with CP had injuries of the ascending tracts (e.g. the SCP and sensory tract), and that additional MCP injury might increase the severity of CP. Quantitative tractography assessment at term-equivalent age may be useful for screening preterm infants for prediction of future motor impairments. Copyright © 2018 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

Regionally-Specific Diffusion Tensor Imaging in Mild Cognitive Impairment and Alzheimer’s Disease

PubMed Central

Mielke, M.M.; Kozauer, N.A.; Chan, K.C.G.; George, M.; Toroney, J.; Zerrate, M.; Bandeen-Roche, K.; Wang, M-C; vanZijl, P.; Pekar, J.J.; Mori, S.; Lyketsos, C.G.; Albert, M.

2009-01-01

Background Diffusion tensor imaging (DTI) studies have shown significant cross-sectional differences among normal controls (Bozzali et al., 2002), mild cognitive impairment (Robbins et al.) and Alzheimer’s disease (AD) patients in several fiber tracts in the brain, but longitudinal assessment is needed. Methods We studied 75 participants (25 NC, 25 amnestic MCI, and 25 mild AD) at baseline and 3 months later, with both imaging and clinical evaluations. Fractional anisotropy (Bozzali et al., 2002) was analyzed in regions of interest (ROIs) in: (1) fornix, (2) cingulum bundle, (3) splenium, and (4) cerebral peduncles. Clinical data included assessments of clinical severity and cognitive function. Cross-sectional and longitudinal differences in FA, within each ROI, were analyzed with generalized estimating equations (GEE). Results Cross-sectionally, AD patients had lower FA than NC (p<0.05) at baseline and 3 months in the fornix and anterior portion of the cingulum bundle. Compared to MCI, AD cases had lower FA (p<0.05) in these regions and the splenium at 0 and 3 months. Both the fornix and anterior cingulum correlated across all clinical cognitive scores; lower FA in these ROIs corresponded to worse performance. Over the course of 3 months, when the subjects were clinically stable, the ROIs were also largely stable. Conclusions Using DTI, findings indicate FA is decreased in specific fiber tracts among groups of subjects that vary along the spectrum from normal to AD, and that this measure is stable over short periods of time. The fornix is a predominant outflow tract of the hippocampus and may be an important indicator of AD progression. PMID:19457371

White matter alterations and their associations with motor function in young adults born preterm with very low birth weight.

PubMed

Hollund, Ingrid Marie Husby; Olsen, Alexander; Skranes, Jon; Brubakk, Ann-Mari; Håberg, Asta K; Eikenes, Live; Evensen, Kari Anne I

2018-01-01

Very low birth weight (VLBW: ≤ 1500 g) individuals have an increased risk of white matter alterations and neurodevelopmental problems, including fine and gross motor problems. In this hospital-based follow-up study, the main aim was to examine white matter microstructure and its relationship to fine and gross motor function in 31 VLBW young adults without cerebral palsy compared with 31 term-born controls, at mean age 22.6 ± 0.7 years. The participants were examined with tests of fine and gross motor function (Trail Making Test-5: TMT-5, Grooved Pegboard, Triangle from Movement Assessment Battery for Children-2: MABC-2 and High-level Mobility Assessment Tool: HiMAT) and diffusion tensor imaging (DTI). Probabilistic tractography of motor pathways of the corticospinal tract (CST) and corpus callosum (CC) was performed. Fractional anisotropy (FA) was calculated in non-crossing (capsula interna in CST, body of CC) and crossing (centrum semiovale) fibre regions along the tracts and examined for group differences. Associations between motor test scores and FA in the CST and CC were investigated with linear regression. Tract-based spatial statistics (TBSS) was used to examine group differences in DTI metrics in all major white matter tracts. The VLBW group had lower scores on all motor tests compared with controls, however, only statistically significant for TMT-5. Based on tractography, FA in the VLBW group was lower in non-crossing fibre regions and higher in crossing fibre regions of the CST compared with controls. Within the VLBW group, poorer fine motor function was associated with higher FA in crossing fibre regions of the CST, and poorer bimanual coordination was additionally associated with lower FA in crossing fibre regions of the CC. Poorer gross motor function was associated with lower FA in crossing fibre regions of the CST and CC. There were no associations between motor function and FA in non-crossing fibre regions of the CST and CC within the VLBW group. In the TBSS analysis, the VLBW group had lower FA and higher mean diffusivity compared with controls in all major white matter tracts. The findings in this study may indicate that the associations between motor function and FA are caused by other tracts crossing the CST and CC, and/or by alterations in the periventricular white matter in the centrum semiovale. Some of the associations were in the opposite direction than hypothesized, thus higher FA does not always indicate better function. Furthermore, widespread white matter alterations in VLBW individuals persist into young adulthood.

Enhanced performance of magnesium alloy for drug-eluting vascular scaffold application

NASA Astrophysics Data System (ADS)

Dong, Hongzhou; Li, Daikun; Mao, Daoyong; Bai, Ningning; Chen, Yashi; Li, Qing

2018-03-01

Bio-absorbable magnesium alloys drug-eluting vascular scaffold was developed to resolve the defect of permanent metal and drug-eluting stents, most notably a chronic vessel wall inflammation and the risk of stent thrombosis. Nevertheless, violent chemical reaction and rapid degradation under physiological conditions limits their application. Furthermore, multifunctional drug-eluting stents which could reduce the formation of thrombus and repair the damaged vessels need more attention to fundamentally cure the coronary artery disease. Herein, a drug delivery system (Mg/MgO/PLA-FA) which can realize sustainable release of ferulaic acid was designed via anodic oxidation process and dip coating process. Electrochemical tests and immersion experiments showed that the superior anticorrosion behavior, it is due to the dense MgO-PLA composite layer. The released ferulaic acid can effectively decrease platelets adhesion and aggregation during the early stage of implantation. Besides, hemolysis tests showed that the composite coatings endowed the Mg alloy with a low hemolysis ratio. The Mg/MgO/PLA-FA composite materials may be appropriate for applications on biodegradable Mg alloys drug-eluting stents.

A comprehensive study of the cool gas content of massive dark matter halos

NASA Astrophysics Data System (ADS)

Gauthier, Jean-Rene

2011-09-01

This thesis is based on the results of an on-going investigation of the cool, T ˜ 104 K, gas present in massive dark matter halos traced by luminous red galaxies (LRGs) at z ˜ 0.5. It consists of three parts. The first part (Chapter 2) presents a series of measurements of the large-scale clustering of MgII lambdalambda 2796,2803 absorbers with respect to a population of LRGs. From the cross-correlation measurements between the absorbers and the galaxies, the mean bias of the dark matter halos in which the absorbers reside is derived. One finds a 1-sigma anti-correlation between mean halo bias and absorber strength W r(2796) that translates into a 1-sigma anti-correlation between mean galaxy mass and Wr(2796). The results indicate that a significant fraction of the MgII absorber population of W r(2796) = 1-1.5A are found in group-size dark matter halos of log Mh < 13.4, whereas absorbers of Wr(2796) > 1.5A are primarily seen in halos of log Mh < 12.7. In the second part of this thesis, a series of constraints on the covering fraction of cool gas are derived in Chapter 3. The results of an on-going spectroscopic follow-up of close LRG-Mg II absorber pairs are presented in Chapter 4. This spectroscopic sample consists of 70 photometrically selected LRGs at physical projected separations rho <˜ 400 kpc/h from a QSO sightline. The moderate-resolution spectra confirm a physical association between the cool gas revealed by the presence of MgII absorption features and the LRG halo in 15 cases. From a pair sample with no prior knowledge of the presence/absence of MgII absorbers, a covering fraction kappa = 0.13+0.05-0.06 is found for Wr(2796) > 0.3A and rho < 400 kpc/h. The third part of this thesis addresses the results of a stellar population synthesis analysis done on stacked spectra of MgII absorbing and non-absorbing LRG subsamples. The main finding of this analysis is that LRGs with or without associated MgII absorbers share similar star formation histories and are best described by old stellar population models (>˜ 1 Gyr). Younger stellar populations (<˜1 Gyr) fail to reproduce their spectra. The primarily old stellar populations in the LRGs indicate that recent starburst driven outflows are unlikely to explain the observed MgII absorbers at large distances from the LRGs. Finally, high-resolution spectra of seven MgII absorbers found in the vicinity of LRGs and associated deep, R-band images of the QSO-LRG fields are presented in Appendix A. These new data are crucial to study the kinematics of the gas and constrain its physical origin.

Chromophoric Dissolved Organic Matter in Southwestern Greenland Lakes

NASA Astrophysics Data System (ADS)

Osburn, C. L.; Giles, M. E.; Underwood, G. J. C.

2014-12-01

Dissolved organic matter (DOM) is an important property of Arctic lake ecosystems, originating from allochthonous inputs from catchments and autochthonous production by plankton in the water column. Little is known about the quality of DOM in Arctic lakes that lack substantial inputs from catchments and such lakes are abundant in southwestern Greenland. Colored dissolved organic matter (CDOM), the fraction that absorbs ultraviolet (UV) and visible light, is the controlling factor for the optical properties of many surface waters and as well informs on the quality of DOM. We examined the quality of CDOM in 21 lakes in southwestern Greenland, from the ice sheet to the coast, as part of a larger study examining the role of DOM in regulating microbial communities in these lakes. DOM was size fractioned and absorbance and fluorescence was measured on each size fraction, as well as on bulk DOM. The specific ultraviolet absorbance (SUVA) at 254 nm (SUVA254), computed by normalizing absorption (a254) to dissolved organic carbon (DOC) concentration, provided an estimate of the aromatic carbon content of DOM. SUVA values were generally <2, indicating low aromatic content. Parallel factor analysis (PARAFAC) of CDOM fluorescence was used to determine the relative abundance of allochthonous and autochthonous DOM in all size fractions. Younger lakes near the ice sheet and lakes near the coast had lower amounts of CDOM and appeared more microbial in quality. However, lakes centrally located between the ice sheet and the coast had the highest CDOM concentrations and exhibited strong humic fluorescence. Overall distinct differences in CDOM quality were observed between lake locations and among DOM size fractions.

Bioavailability of biologically sequestered cadmium and the implications of metal detoxification

USGS Publications Warehouse

Wallace, W.G.; Lopez, G.R.

1997-01-01

The deposit-feeding oligochaete Limnodrilus hoffmeisteri possesses metallothionein-like proteins and metal-rich granules for storing and detoxifying cadmium (Cd). In this study we investigated the bioavailability of Cd sequestered within this oligochaete by conducting feeding experiments with 109Cd-labeled oligochaetes and the omnivorous grass shrimp Palaemonetes pugio. We also make predictions on Cd trophic transfer based on oligochaete subcellular Cd distributions and absorption efficiencies of Cd by shrimp Cytosol [including metallothionein-like proteins and other proteins) and a debris fraction (including metal-rich granules and tissue fragments) isolated from homogenized 109Cd-labeled oligochaetes were embedded in gelatin and fed to shrimp. The 109Cd absorption efficiencies of shrimp fed these subcellular fractions were 84.8 and 48.6%, respectively, and were significantly different (p < 0.001), indicating that 109Cd bound in these fractions was not equally available to a predator. Mass balance equations demonstrate that shrimp fed whole worms absorb 61.5% of the ingested 109Cd, an absorption efficiency similar to that obtained experimentally (57.1%). Furthermore, the majority of the absorbed 109Cd comes from the fraction containing metallothionein-like proteins (i.e. cytosol). 109Cd absorbed from the debris fraction probably comes from the digestion of tissue fragments, rather than metal-rich granules. The ecological significance of these findings is that prey detoxification mechanisms may mediate the bioreduction or bioaccumulation of toxic metals along fond chains by altering metal bioavailability. Another important finding is that trophic transfer of metal can be predicted based on the subcellular metal distribution of prey.

Neonatal Microstructural Development of the Internal Capsule on Diffusion Tensor Imaging Correlates with Severity of Gait and Motor Deficits

ERIC Educational Resources Information Center

Rose, Jessica; Mirmiran, Majid; Butler, Erin E.; Lin, Cindy Y.; Barnes, Patrick D.; Kermoian, Rosanne; Stevenson, David K.

2007-01-01

Neonatal microstructural development in the posterior limbs of the internal capsule (PLIC) was assessed using diffusion tensor imaging (DTI) fractional anisotropy (FA) in 24 very-low-birthweight preterm infants at 37 weeks' gestational age and compared with the children's gait and motor deficits at 4 years of age. There were 14 participants with…

Multifractal Modeling of Turbulent Mixing

NASA Astrophysics Data System (ADS)

Samiee, Mehdi; Zayernouri, Mohsen; Meerschaert, Mark M.

2017-11-01

Stochastic processes in random media are emerging as interesting tools for modeling anomalous transport phenomena. Applications include intermittent passive scalar transport with background noise in turbulent flows, which are observed in atmospheric boundary layers, turbulent mixing in reactive flows, and long-range dependent flow fields in disordered/fractal environments. In this work, we propose a nonlocal scalar transport equation involving the fractional Laplacian, where the corresponding fractional index is linked to the multifractal structure of the nonlinear passive scalar power spectrum. This work was supported by the AFOSR Young Investigator Program (YIP) award (FA9550-17-1-0150) and partially by MURI/ARO (W911NF-15-1-0562).

Diffusion tensor imaging assessment of brain white matter maturation during the first postnatal year.

PubMed

Provenzale, James M; Liang, Luxia; DeLong, David; White, Leonard E

2007-08-01

The purpose of this study was to use diffusion-weighted and diffusion tensor imaging to investigate the status of cerebral white matter (WM) at term gestation and the rate of WM maturation throughout the first year of life in healthy infants. Fifty-three children (35 boys) ranging in age from 1.5 weeks premature to 51.5 weeks (mean age, 22.9 weeks) underwent conventional MRI, diffusion imaging in three directions (b = 1,000 s/mm2), and diffusion tensor imaging with gradient encoding in six directions, all on a 1.5-T MRI system. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured in three deep WM structures (posterior limb of internal capsule, genu, and splenium of corpus callosum) and two peripheral WM regions (associational WM underlying prefrontal and posterior parietal cortex) with a standard region of interest (44 +/- 4 cm2). ADC and FA were expressed as a percentage of corresponding values measured in a group of healthy young adults. Mean ADC and FA values for deep and peripheral WM were plotted against gestational age normalized to term. The data were fit best with a broken-line linear regression model with a breakpoint at 100 days. ADC and FA values at term were estimated according to the intercept of the initial linear period (before day 100) with day 0. The slope of the linear fits was used to determine the rate of WM maturation in both the early and the late (after day 100) periods. Multivariate analysis of variance tests were used to compare deep and peripheral WM structures at term and at representative early and late ages (days 30 and 200) and to compare rates of ADC and FA maturation in early and late periods within the first year. At term, peripheral WM was less mature than deep WM according to results of extrapolation of ADC and FA values in the first 100 days of life to day 0 (p < 0.01). Mean ADC and FA value (percentage of mean adult value) for peripheral WM were 1.32 x 10(-3) mm2/s (163%) and 0.16 (32%), respectively, and 1.09 x 10(-3) mm2/s (143%) and 0.36 (54%), respectively, for deep WM. On day 30 and day 200, estimated mean ADC and FA continued to show greater diffusion (higher ADC) and less anisotropy (lower FA value) in peripheral WM (p <0.01). During the first year of postnatal life, both ADC and FA matured at higher rates before postnatal day 100 compared with a later time. Differences were observed in rates of maturation in the first 100 days when rates of decrease in ADC and increase in FA were compared between peripheral WM and deep WM; however, the maturational trends differed whether ADC or FA was examined. The early rate of ADC decrease (maturation) was twice as great for peripheral WM than for deep WM (p < 0.01) unexpectedly, but the opposite pattern was observed for FA. The early rate of FA increase (maturation) was approximately one half as great for peripheral WM as for deep WM (p = 0.01). Throughout the rest of the first year, no differences were observed in the rates of change in either index between peripheral WM and deep WM. At term, both ADC and FA differ significantly in peripheral WM and deep WM, deep WM structures being more mature. Both deep WM and peripheral WM mature more rapidly during approximately the first 3 months in comparison with the rest of the first year. Unexpected differences in early (first 100 days) rates of maturation assessed with diffusion-weighted (ADC) and diffusion tensor (FA) imaging suggest that these two techniques may be sensitive to different aspects of WM maturation in the early perinatal period.

Diffusion Tensor Imaging of Incentive Effects in Prospective Memory after Pediatric Traumatic Brain Injury

PubMed Central

Wilde, Elisabeth A.; Bigler, Erin D.; Chu, Zili; Yallampalli, Ragini; Oni, Margaret B.; Wu, Trevor C.; Ramos, Marco A.; Pedroza, Claudia; Vásquez, Ana C.; Hunter, Jill V.; Levin, Harvey S.

2011-01-01

Abstract Few studies exist investigating the brain-behavior relations of event-based prospective memory (EB-PM) impairments following traumatic brain injury (TBI). To address this, children with moderate-to-severe TBI performed an EB-PM test with two motivational enhancement conditions and underwent concurrent diffusion tensor imaging (DTI) at 3 months post-injury. Children with orthopedic injuries (OI; n = 37) or moderate-to-severe TBI (n = 40) were contrasted. Significant group differences were found for fractional anisotropy (FA) and apparent diffusion coefficient for orbitofrontal white matter (WM), cingulum bundles, and uncinate fasciculi. The FA of these WM structures in children with TBI significantly correlated with EB-PM performance in the high, but not the low motivation condition. Regression analyses within the TBI group indicated that the FA of the left cingulum bundle (p = 0.003), left orbitofrontal WM (p < 0.02), and left (p < 0.02) and right (p < 0.008) uncinate fasciculi significantly predicted EB-PM performance in the high motivation condition. We infer that the cingulum bundles, orbitofrontal WM, and uncinate fasciculi are important WM structures mediating motivation-based EB-PM responses following moderate-to-severe TBI in children. PMID:21250917

relationship between diffusion tensor imaging findings and cognitive outcomes following adult traumatic brain injury: A meta-analysis.

PubMed

Wallace, E J; Mathias, J L; Ward, L

2018-05-24

Cognitive impairments are common following a traumatic brain injury (TBI) and frequently result from white matter (WM) damage. This damage can be quantified using diffusion tensor imaging (DTI), which measures the directionality (fractional anisotropy: FA) and amount (mean diffusivity/apparent diffusion coefficient: MD/ADC) of water diffusion in WM, with high FA and low MD/ADC thought to indicate greater WM integrity. However, the relationship between DTI and cognitive outcomes is currently unclear. The data from 20 studies that examined the relationship between WM integrity (measured using DTI) and cognition (categorised into seven domains) following mild-severe adult TBI were meta-analysed. Overall, high FA and low MD/ADC in most brain regions was associated with better cognitive performance, with memory and attention most strongly related to DTI findings. Specifically, memory and/or attention were very strongly related to DTI findings in the corpus callosum, fornix, internal capsule, arcuate and uncinate fasciculi. However, most findings were based on single studies and therefore await replication. Larger-scale, longitudinal studies are now needed to determine the predictive utility of DTI. Copyright © 2018. Published by Elsevier Ltd.

Maternal adiposity negatively influences infant brain white matter development.

PubMed

Ou, Xiawei; Thakali, Keshari M; Shankar, Kartik; Andres, Aline; Badger, Thomas M

2015-05-01

To study potential effects of maternal body composition on central nervous system (CNS) development of newborn infants. Diffusion tensor imaging (DTI) was used to evaluate brain white matter development in 2-week-old, full-term, appropriate for gestational age (AGA) infants from uncomplicated pregnancies of normal-weight (BMI < 25 at conception) or obese ( BMI = 30 at conception) and otherwise healthy mothers. Tract-based spatial statistics (TBSS) analyses were used for voxel-wise group comparison of fractional anisotropy (FA), a sensitive measure of white matter integrity. DNA methylation analyses of umbilical cord tissue focused on genes known to be important in CNS development were also performed. Newborns from obese women had significantly lower FA values in multiple white matter regions than those born of normal-weight mothers. Global and regional FA values negatively correlated (P < 0.05) with maternal fat mass percentage. Linear regression analysis followed by gene ontology enrichment showed that methylation status of 68 CpG sites representing 57 genes with GO terms related to CNS development was significantly associated with maternal adiposity status. These results suggest a negative association between maternal adiposity and white matter development in offspring. © 2015 The Obesity Society.

Prediction of neurodevelopmental outcome after hypoxic-ischemic encephalopathy treated with hypothermia by diffusion tensor imaging analyzed using tract-based spatial statistics.

PubMed

Tusor, Nora; Wusthoff, Courtney; Smee, Natalie; Merchant, Nazakat; Arichi, Tomoki; Allsop, Joanna M; Cowan, Frances M; Azzopardi, Denis; Edwards, A David; Counsell, Serena J

2012-07-01

Objective biomarkers are needed to assess neuroprotective therapies after perinatal hypoxic-ischemic encephalopathy (HIE). We tested the hypothesis that, in infants who underwent therapeutic hypothermia after perinatal HIE, neurodevelopmental performance was predicted by fractional anisotropy (FA) values in the white matter (WM) on early diffusion tensor imaging (DTI) as assessed by means of tract-based spatial statistics (TBSS). We studied 43 term infants with HIE. Developmental assessments were carried out at a median (range) age of 24 (12-28) mo. As compared with infants with favorable outcomes, those with unfavorable outcomes had significantly lower FA values (P < 0.05) in the centrum semiovale, corpus callosum (CC), anterior and posterior limbs of the internal capsule, external capsules, fornix, cingulum, cerebral peduncles, optic radiations, and inferior longitudinal fasciculus. In a second analysis in 32 assessable infants, the Griffiths Mental Development Scales (Revised) (GMDS-R) showed a significant linear correlation (P < 0.05) between FA values and developmental quotient (DQ) and all its component subscale scores. DTI analyzed by TBSS provides a qualified biomarker that can be used to assess the efficacy of additional neuroprotective therapies after HIE.

Experience-Related Structural Changes of Degenerated Occipital White Matter in Late-Blind Humans – A Diffusion Tensor Imaging Study

PubMed Central

Dietrich, Susanne; Hertrich, Ingo; Kumar, Vinod; Ackermann, Hermann

2015-01-01

Late-blind humans can learn to understand speech at ultra-fast syllable rates (ca. 20 syllables/s), a capability associated with hemodynamic activation of the central-visual system. Thus, the observed functional cross-modal recruitment of occipital cortex might facilitate ultra-fast speech processing in these individuals. To further elucidate the structural prerequisites of this skill, diffusion tensor imaging (DTI) was conducted in late-blind subjects differing in their capability of understanding ultra-fast speech. Fractional anisotropy (FA) was determined as a quantitative measure of the directionality of water diffusion, indicating fiber tract characteristics that might be influenced by blindness as well as the acquired perceptual skills. Analysis of the diffusion images revealed reduced FA in late-blind individuals relative to sighted controls at the level of the optic radiations at either side and the right-hemisphere dorsal thalamus (pulvinar). Moreover, late-blind subjects showed significant positive correlations between FA and the capacity of ultra-fast speech comprehension within right-hemisphere optic radiation and thalamus. Thus, experience-related structural alterations occurred in late-blind individuals within visual pathways that, presumably, are linked to higher order frontal language areas. PMID:25830371

Fatty-acid profiles of white muscle and liver in stream-maturing steelhead trout Oncorhynchus mykiss from early migration to kelt emigration

USGS Publications Warehouse

Penney, Zachary L.; Moffitt, Christine M.

2015-01-01

The profiles of specific fatty acids (FA) in white muscle and liver of fasting steelhead troutOncorhynchus mykiss were evaluated at three periods during their prespawning migration and at kelt emigration in the Snake–Columbia River of Washington, Oregon and Idaho, to improve the understanding of energy change. Twenty-seven FAs were identified; depletion of 10 of these was positively correlated in liver and white muscle of prespawning O. mykiss. To observe relative changes in FA content more accurately over sampling intervals, the lipid fraction of tissues was used to normalize the quantity of individual FA to an equivalent tissue wet mass. Saturated and monounsaturated FAs were depleted between upstream migration in September and kelt emigration in June, whereas polyunsaturated FAs were more conserved. Liver was depleted of FAs more rapidly than muscle. Three FAs were detected across all sampling intervals: 16:0, 18:1 and 22:6n3, which are probably structurally important to membranes. When structurally important FAs of O. mykiss are depleted to provide energy, physiological performance and survival may be affected.

Higher education is an age-independent predictor of white matter integrity and cognitive control in late adolescence.

PubMed

Noble, Kimberly G; Korgaonkar, Mayuresh S; Grieve, Stuart M; Brickman, Adam M

2013-09-01

Socioeconomic status is an important predictor of cognitive development and academic achievement. Late adolescence provides a unique opportunity to study how the attainment of socioeconomic status (in the form of years of education) relates to cognitive and neural development, during a time when age-related cognitive and neural development is ongoing. During late adolescence it is possible to disambiguate age- and education-related effects on the development of these processes. Here we assessed the degree to which higher educational attainment was related to performance on a cognitive control task, controlling for age. We then used diffusion tensor imaging (DTI) to assess the degree to which white matter microstructure might mediate this relationship. When covarying age, significant associations were found between educational attainment and fractional anisotropy (FA) in the superior longitudinal fasciculus (SLF) and cingulum bundle (CB). Further, when covarying age, FA in these regions was associated with cognitive control. Finally, mediation analyses revealed that the age-independent association between educational attainment and cognitive control was completely accounted for by FA in these regions. The uncinate fasciculus, a late-myelinated control region not implicated in cognitive control, did not mediate this effect. © 2013 John Wiley & Sons Ltd.

Thalamic diffusion differences related to cognitive function in white matter lesions.

PubMed

Fernández-Andújar, Marina; Soriano-Raya, Juan José; Miralbell, Júlia; López-Cancio, Elena; Cáceres, Cynthia; Bargalló, Núria; Barrios, Maite; Arenillas, Juan Francisco; Toran, Pere; Alzamora, Maite; Clemente, Imma; Dávalos, Antoni; Mataró, Maria

2014-05-01

Cerebral white matter lesions (WMLs) are related to cognitive deficits, probably due to a disruption of frontal-subcortical circuits. We explored thalamic diffusion differences related to white matter lesions (WMLs) and their association with cognitive function in middle-aged individuals. Ninety-six participants from the Barcelona-AsIA Neuropsychology Study were included. Participants were classified into groups based on low grade and high grade of periventricular hyperintensities (PVHs) and deep white matter hyperintensities (DWMHs). Tract-Based Spatial Statistics was used to study thalamic diffusion differences between groups. Mean fractional anisotropy (FA) values in significant areas were calculated for each subject and correlated with cognitive performance. Participants with high-grade PVHs and DWMHs showed lower FA thalamic values compared to those with low-grade PVHs and DWMHs, respectively. Decreased FA thalamic values in high-grade DWMHs, but not high-grade PVH, were related to lower levels of performance in psychomotor speed, verbal fluency, and visuospatial skills. Thalamic diffusion differences are related to lower cognitive function only in participants with high-grade DWMHs. These results support the hypothesis that fronto-subcortical disruption is associated with cognitive function only in DWMHs. Copyright © 2014 Elsevier Inc. All rights reserved.

Analysis of alterations in white matter integrity of adult patients with comitant exotropia.

PubMed

Li, Dan; Li, Shenghong; Zeng, Xianjun

2018-05-01

Objective This study was performed to investigate structural abnormalities of the white matter in patients with comitant exotropia using the tract-based spatial statistics (TBSS) method. Methods Diffusion tensor imaging data from magnetic resonance images of the brain were collected from 20 patients with comitant exotropia and 20 age- and sex-matched healthy controls. The FMRIB Software Library was used to compute the diffusion measures, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). These measures were obtained using voxel-wise statistics with threshold-free cluster enhancement. Results The FA values in the right inferior fronto-occipital fasciculus (IFO) and right inferior longitudinal fasciculus were significantly higher and the RD values in the bilateral IFO, forceps minor, left anterior corona radiata, and left anterior thalamic radiation were significantly lower in the comitant exotropia group than in the healthy controls. No significant differences in the MD or AD values were found between the two groups. Conclusions Alterations in FA and RD values may indicate the underlying neuropathologic mechanism of comitant exotropia. The TBSS method can be a useful tool to investigate neuronal tract participation in patients with this disease.

MRI-negative refractory partial epilepsy: role for diffusion tensor imaging in high field MRI.

PubMed

Chen, Qin; Lui, Su; Li, Chun-Xiao; Jiang, Li-Jun; Ou-Yang, Luo; Tang, He-Han; Shang, Hui-Fang; Huang, Xiao-Qi; Gong, Qi-Yong; Zhou, Dong

2008-07-01

Our aim is to use the high field MR scanner (3T) to verify whether diffusion tensor imaging (DTI) could help in locating the epileptogenic zone in patients with MRI-negative refractory partial epilepsy. Fifteen patients with refractory partial epilepsy who had normal conventional MRI, and 40 healthy volunteers were recruited for the study. DTI was performed on a 3T MR scanner, individual maps of mean diffusivity (MD) and fractional anisotropy (FA) were calculated, and Voxel-Based Analysis (VBA) was performed for individual comparison between patients and controls. Voxel-based analysis revealed significant MD increase in variant regions in 13 patients. The electroclinical seizure localization was concurred to seven patients. No patient exhibited regions of significant decreased MD. Regions of significant reduced FA were observed in five patients, with two of these concurring with electroclinical seizure localization. Two patients had regions of significant increase in FA, which were distinct from electroclinical seizure localization. Our study's results revealed that DTI is a responsive neuroradiologic technique that provides information about the epileptogenic areas in patients with MRI-negative refractory partial epilepsy. This technique may also helpful in pre-surgical evaluation.

Intrinsic disruption of white matter microarchitecture in first-episode, drug-naive major depressive disorder: A voxel-based meta-analysis of diffusion tensor imaging.

PubMed

Chen, Guangxiang; Guo, Yi; Zhu, Hongyan; Kuang, Weihong; Bi, Feng; Ai, Hua; Gu, Zhongwei; Huang, Xiaoqi; Lui, Su; Gong, Qiyong

2017-06-02

Previous studies have demonstrated the influences of episodes and antidepressant drugs on white matter (WM) in patients with major depressive disorder (MDD). However, most diffusion tensor imaging (DTI) studies included highly heterogeneous individuals with different numbers of depressive episodes or medication status. To exclude the confounding effects of multiple episodes or medication, we conducted a quantitative voxel-based meta-analysis of fractional anisotropy (FA) in patients with first-episode, drug-naive MDD to identify the intrinsic WM alterations involved in the pathogenesis of MDD. The pooled meta-analysis revealed significant FA reductions in the body of the corpus callosum (CC), bilateral anterior limb of the internal capsule (ALIC), right inferior temporal gyrus (ITG) and right superior frontal gyrus (SFG) in MDD patients relative to healthy controls. Meta-regression analyses revealed that FA reduction in the right ALIC and right SFG was negatively correlated with symptom severity and duration of depression, respectively. Our findings provide robust evidence that the WM impairments in the interhemispheric connections and frontal-subcortical neuronal circuits may play an important role in MDD pathogenesis. Copyright © 2017. Published by Elsevier Inc.

A systematic review and meta-analysis of tract-based spatial statistics studies regarding attention-deficit/hyperactivity disorder.

PubMed

Chen, Lizhou; Hu, Xinyu; Ouyang, Luo; He, Ning; Liao, Yi; Liu, Qi; Zhou, Ming; Wu, Min; Huang, Xiaoqi; Gong, Qiyong

2016-09-01

Diffusion tensor imaging (DTI) studies that use tract-based spatial statistics (TBSS) have demonstrated the microstructural abnormalities of white matter (WM) in patients with attention-deficit/hyperactivity disorder (ADHD); however, robust conclusions have not yet been drawn. The present study integrated the findings of previous TBSS studies to determine the most consistent WM alterations in ADHD via a narrative review and meta-analysis. The literature search was conducted through October 2015 to identify TBSS studies that compared fractional anisotropy (FA) between ADHD patients and healthy controls. FA reductions were identified in the splenium of the corpus callosum (CC) that extended to the right cingulum, right sagittal stratum, and left tapetum. The first two clusters retained significance in the sensitivity analysis and in all subgroup analyses. The FA reduction in the CC splenium was negatively associated with the mean age of the ADHD group. We hypothesize that, in addition to the fronto-striatal-cerebellar circuit, the disturbed WM matter tracts that integrate the bilateral hemispheres and posterior-brain circuitries play a crucial role in the pathophysiology of ADHD. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ocean acidification reduces transfer of essential biomolecules in a natural plankton community

PubMed Central

Bermúdez, J. Rafael; Riebesell, Ulf; Larsen, Aud; Winder, Monika

2016-01-01

Ocean acidification (OA), a process of increasing seawater acidity caused by the uptake of anthropogenic carbon dioxide (CO2) by the ocean, is expected to change surface ocean pH to levels unprecedented for millions of years, affecting marine food web structures and trophic interactions. Using an in situ mesocosm approach we investigated effects of OA on community composition and trophic transfer of essential fatty acids (FA) in a natural plankton assemblage. Elevated pCO2 favored the smallest phytoplankton size class in terms of biomass, primarily picoeukaryotes, at the expense of chlorophyta and haptophyta in the nano-plankton size range. This shift in community composition and size structure was accompanied by a decline in the proportion of polyunsaturated FA (PUFA) to total FA content in the nano- and picophytoplankton size fractions. This decline was mirrored in a continuing reduction in the relative PUFA content of the dominant copepod, Calanus finmarchicus, which primarily fed on the nano-size class. Our results demonstrate that a shift in phytoplankton community composition and biochemical composition in response to rising CO2 can affect the transfer of essential compounds to higher trophic levels, which rely on their prey as a source for essential macromolecules. PMID:27324057

[The in vitro dissolution of total composition of the tablet of rhizomes of Ligusticum chuanxiong components and in vitro-in vivo correlation by the method of area under the absorbance-wavelength curve].

PubMed

Lai, Hong-qiang; Hu, Yue; Li, Xiao-dong

2015-06-01

To discuss the availability of evaluation on the dissolution studies of the multicomponents in traditional Chinese medicine, the in vitro dissolution of total composition of the tablet of rhizomes of Ligusticum chuanxiong components and its correlation with the in vivo were studied by the method of area under the absorbance-wavelength curve (AUAWC). Taken the tablet of rhizomes of Ligusticum chuanxiong components which is composed of sodium ferulate and ligustrazine hydrochloride as subject model, the dissolution tests were carried out with basket method. The plasma concentrations of tablets in different rats were determined by AUAWC at different interval times. The in vivo absorption percentage was calculated by Wagner-Nelson equation to evaluate the in vitro and in vivo correlation. According to the results, the cumulative dissolution in vitro of total composition of tablets of rhizomes of Ligusticum chuanxiong components at 60 min was 90.65% in water by AUAWC. The in vivo pharmacokinetics is fitted with an one-compartment model. The linear equation based on the cumulative dissolution rate (fr) and absorption percentage (fa) at 5, 10, 20, 30 and 60 min was fa = 0.819 7 fr+0.183 and the correlation coefficient was 0.959 5, which showed a good correlation between the in vitro dissolution and the in vivo absorption percentage. The method of AUAWC can be used accurately, feasibly and conveniently to evaluate the in vitro and in vivo correlation of total composition of tablets of rhizomes of Ligusticum chuanxiong components, which will provide better guidance to study the in vitro and in vivo correlation of sustained release preparation etc under complex system of traditional Chinese medicine in the future.

Redefining relative biological effectiveness in the context of the EQDX formalism: implications for alpha-particle emitter therapy.

PubMed

Hobbs, Robert F; Howell, Roger W; Song, Hong; Baechler, Sébastien; Sgouros, George

2014-01-01

Alpha-particle radiopharmaceutical therapy (αRPT) is currently enjoying increasing attention as a viable alternative to chemotherapy for targeting of disseminated micrometastatic disease. In theory, αRPT can be personalized through pre-therapeutic imaging and dosimetry. However, in practice, given the particularities of α-particle emissions, a dosimetric methodology that accurately predicts the thresholds for organ toxicity has not been reported. This is in part due to the fact that the biological effects caused by α-particle radiation differ markedly from the effects caused by traditional external beam (photon or electron) radiation or β-particle emitting radiopharmaceuticals. The concept of relative biological effectiveness (RBE) is used to quantify the ratio of absorbed doses required to achieve a given biological response with alpha particles versus a reference radiation (typically a beta emitter or external beam radiation). However, as conventionally defined, the RBE varies as a function of absorbed dose and therefore a single RBE value is limited in its utility because it cannot be used to predict response over a wide range of absorbed doses. Therefore, efforts are underway to standardize bioeffect modeling for different fractionation schemes and dose rates for both nuclear medicine and external beam radiotherapy. Given the preponderant use of external beams of radiation compared to nuclear medicine in cancer therapy, the more clinically relevant quantity, the 2 Gy equieffective dose, EQD2(α/β), has recently been proposed by the ICRU. In concert with EQD2(α/β), we introduce a new, redefined RBE quantity, named RBE2(α/β), as the ratio of the two linear coefficients that characterize the α particle absorbed dose-response curve and the low-LET megavoltage photon 2 Gy fraction equieffective dose-response curve. The theoretical framework for the proposed new formalism is presented along with its application to experimental data obtained from irradiation of a breast cancer cell line. Radiobiological parameters are obtained using the linear quadratic model to fit cell survival data for MDA-MB-231 human breast cancer cells that were irradiated with either α particles or a single fraction of low-LET (137)Cs γ rays. From these, the linear coefficient for both the biologically effective dose (BED) and the EQD2(α/β) response lines were derived for fractionated irradiation. The standard RBE calculation, using the traditional single fraction reference radiation, gave RBE values that ranged from 2.4 for a surviving fraction of 0.82-6.0 for a surviving fraction of 0.02, while the dose-independent RBE2(4.6) value was 4.5 for all surviving fraction values. Furthermore, bioeffect modeling with RBE2(α/β) and EQD2(α/β) demonstrated the capacity to predict the surviving fraction of cells irradiated with acute and fractionated low-LET radiation, α particles and chronic exponentially decreasing dose rates of low-LET radiation. RBE2(α/β) is independent of absorbed dose for α-particle emitters and it provides a more logical framework for data reporting and conversion to equieffective dose than the conventional dose-dependent definition of RBE. Moreover, it provides a much needed foundation for the ongoing development of an α-particle dosimetry paradigm and will facilitate the use of tolerance dose data available from external beam radiation therapy, thereby helping to develop αRPT as a single modality as well as for combination therapies.

Redefining Relative Biological Effectiveness in the Context of the EQDX Formalism: Implications for Alpha-Particle Emitter Therapy.

PubMed

Hobbs, Robert F; Howell, Roger W; Song, Hong; Baechler, Sébastien; Sgouros, George

2013-12-30

Alpha-particle radiopharmaceutical therapy (αRPT) is currently enjoying increasing attention as a viable alternative to chemotherapy for targeting of disseminated micrometastatic disease. In theory, αRPT can be personalized through pre-therapeutic imaging and dosimetry. However, in practice, given the particularities of α-particle emissions, a dosimetric methodology that accurately predicts the thresholds for organ toxicity has not been reported. This is in part due to the fact that the biological effects caused by α-particle radiation differ markedly from the effects caused by traditional external beam (photon or electron) radiation or β-particle emitting radiopharmaceuticals. The concept of relative biological effectiveness (RBE) is used to quantify the ratio of absorbed doses required to achieve a given biological response with alpha particles versus a reference radiation (typically a beta emitter or external beam radiation). However, as conventionally defined, the RBE varies as a function of absorbed dose and therefore a single RBE value is limited in its utility because it cannot be used to predict response over a wide range of absorbed doses. Therefore, efforts are underway to standardize bioeffect modeling for different fractionation schemes and dose rates for both nuclear medicine and external beam radiotherapy. Given the preponderant use of external beams of radiation compared to nuclear medicine in cancer therapy, the more clinically relevant quantity, the 2 Gy equieffective dose, EQD2(α/β), has recently been proposed by the ICRU. In concert with EQD2(α/β), we introduce a new, redefined RBE quantity, named RBE2(α/β), as the ratio of the two linear coefficients that characterize the α particle absorbed dose-response curve and the low-LET megavoltage photon 2 Gy fraction equieffective dose-response curve. The theoretical framework for the proposed new formalism is presented along with its application to experimental data obtained from irradiation of a breast cancer cell line. Radiobiological parameters are obtained using the linear quadratic model to fit cell survival data for MDA-MB-231 human breast cancer cells that were irradiated with either α particles or a single fraction of low-LET 137 Cs γ rays. From these, the linear coefficient for both the biologically effective dose (BED) and the EQD2(α/β) response lines were derived for fractionated irradiation. The standard RBE calculation, using the traditional single fraction reference radiation, gave RBE values that ranged from 2.4 for a surviving fraction of 0.82-6.0 for a surviving fraction of 0.02, while the dose-independent RBE2(4.6) value was 4.5 for all surviving fraction values. Furthermore, bioeffect modeling with RBE2(α/β) and EQD2(α/β) demonstrated the capacity to predict the surviving fraction of cells irradiated with acute and fractionated low-LET radiation, α particles and chronic exponentially decreasing dose rates of low-LET radiation. RBE2(α/β) is independent of absorbed dose for α-particle emitters and it provides a more logical framework for data reporting and conversion to equieffective dose than the conventional dose-dependent definition of RBE. Moreover, it provides a much needed foundation for the ongoing development of an α-particle dosimetry paradigm and will facilitate the use of tolerance dose data available from external beam radiation therapy, thereby helping to develop αRPT as a single modality as well as for combination therapies.

White matter connectivity and Internet gaming disorder

PubMed Central

Jeong, Bum Seok; Han, Doug Hyun; Kim, Sun Mi; Lee, Sang Won; Renshaw, Perry F.

2017-01-01

Internet use and on-line game play stimulate corticostriatal-limbic circuitry in both healthy subjects and subjects with Internet gaming disorder (IGD). We hypothesized that increased fractional anisotropy (FA) with decreased radial diffusivity (RD) would be observed in IGD subjects, compared with healthy control subjects, and that these white matter indices would be associated with clinical variables including duration of illness and executive function. We screened 181 male patients in order to recruit a large number (n = 58) of IGD subjects without psychiatric co-morbidity as well as 26 male healthy comparison subjects. Multiple diffusion-weighted images were acquired using a 3.0 Tesla magnetic resonance imaging scanner. Tract-based spatial statistics was applied to compare group differences in diffusion tensor imaging (DTI) metrics between IGD and healthy comparison subjects. IGD subjects had increased FA values within forceps minor, right anterior thalamic radiation, right corticospinal tract, right inferior longitudinal fasciculus, right cingulum to hippocampus and right inferior fronto-occipital fasciculus (IFOF) as well as parallel decreases in RD value within forceps minor, right anterior thalamic radiation and IFOF relative to healthy control subjects. In addition, the duration of illness in IGD subjects was positively correlated with the FA values (integrity of white matter fibers) and negatively correlated with RD scores (diffusivity of axonal density) of whole brain white matter. In IGD subjects without psychiatric co-morbidity, our DTI results suggest that increased myelination (increased FA and decreased RD values) in right-sided frontal fiber tracts may be the result of extended game play. PMID:25899390

Using CForest to Analyze Diffusion Tensor Imaging Data: A Study of White Matter Integrity in Healthy Aging.

PubMed

McWhinney, Sean R; Tremblay, Antoine; Chevalier, Thérèse M; Lim, Vanessa K; Newman, Aaron J

2016-12-01

Healthy aging has been associated with a global reduction in white matter integrity, which is thought to reflect cognitive decline. The present study aimed to investigate this reduction over a broad range of the life span, using diffusion tensor imaging analyzed with conditional inference random forest modeling (CForest). This approach is sensitive to subtle and potentially nonlinear effects over the age continuum and was used to characterize the progression of decline in greater detail than has been possible in the past. Data were collected from 45 healthy individuals ranging in age from 19 to 67 years. Fractional anisotropy (FA) was estimated using probabilistic tractography for a number of major tracts across the brain. Age coincided with a nonlinear decrease in FA, with onset beginning at ∼30 years of age and the steepest declines occurring later in life. However, several tracts showed a transient increase before this decline. The progression of decline varied by tract, with steeper but later decline occurring in more anterior tracts. Finally, strongly right-handed individuals demonstrated relatively preserved FA until more than a decade following the onset of decline of others. These results demonstrate that using a novel, nonparametric analysis approach, previously reported reductions in FA with healthy aging were confirmed, while at the same time, new insight was provided into the onset and progression of decline, with evidence suggesting increases in integrity continuing into adulthood.

Diffusion tensor imaging in evaluation of human skeletal muscle injury.

PubMed

Zaraiskaya, Tatiana; Kumbhare, Dinesh; Noseworthy, Michael D

2006-08-01

To explore the capability and reliability of diffusion tensor magnetic resonance imaging (DTI) in the evaluation of human skeletal muscle injury. DTI of four patients with gastrocnemius and soleus muscles injuries was compared to eight healthy controls. Imaging was performed using a GE 3.0T short-bore scanner. A diffusion-weighted 2D spin echo echo-planar imaging (EPI) pulse sequence optimized for skeletal muscle was used. From a series of axially acquired diffusion tensor images the diffusion tensor eigenparameters (eigenvalues and eigenvectors), fractional anisotropy (FA), and apparent diffusion coefficient (ADC) were calculated and compared for injured and healthy calf muscles. Two dimensional (2D) projection maps of the principal eigenvectors were plotted to visualize the healthy and pathologic muscle fiber architectures. Clear differences in FA and ADC were observed in injured skeletal muscle, compared to healthy controls. Mean control FA was 0.23 +/- 0.02 for medial and lateral gastrocnemius (mg and lg) muscles, and 0.20 +/- 0.02 for soleus (sol) muscles. In all patients FA values were reduced compared to controls, to as low as 0.08 +/- 0.02. The ADC in controls ranged from 1.41 to 1.31 x 10(-9) m(2)/second, while in patients this was consistently higher. The 2D projection maps revealed muscle fiber disorder in injured calves, while in healthy controls the 2D projection maps show a well organized (ordered) fiber structure. DTI is a suitable method to assess human calf muscle injury.

Neuropsychiatry and White Matter Microstructure in Huntington’s Disease

PubMed Central

Gregory, Sarah; Scahill, Rachael I.; Seunarine, Kiran K.; Stopford, Cheryl; Zhang, Hui; Zhang, Jiaying; Orth, Michael; Durr, Alexandra; Roos, Raymund A.C.; Langbehn, Douglas R.; Long, Jeffrey D.; Johnson, Hans; Rees, Geraint; Tabrizi, Sarah J.; Craufurd, David

2015-01-01

Abstract Background: Neuropsychiatric symptoms in Huntington’s disease (HD) are often evident prior to clinical diagnosis. Apathy is highly correlated with disease progression, while depression and irritability occur at different stages of the disease, both before and after clinical onset. Little is understood about the neural bases of these neuropsychiatric symptoms and to what extent those neural bases are analogous to neuropsychiatric disorders in the general population. Objective: We used Diffusion Tensor Imaging (DTI) to investigate structural connectivity between brain regions and any putative microstructural changes associated with depression, apathy and irritability in HD. Methods: DTI data were collected from 39 premanifest and 45 early-HD participants in the Track-HD study and analysed using whole-brain Tract-Based Spatial Statistics. We used regression analyses to identify white matter tracts whose structural integrity (as measured by fractional anisotropy, FA) was correlated with HADS-depression, PBA-apathy or PBA-irritability scores in gene-carriers and related to cumulative probability to onset (CPO). Results: For those with the highest CPO, we found significant correlations between depression scores and reduced FA in the splenium of the corpus callosum. In contrast, those with lowest CPO demonstrated significant correlations between irritability scores and widespread FA reductions. There was no significant relationship between apathy and FA throughout the whole brain. Conclusions: We demonstrate that white matter changes associated with both depression and irritability in HD occur at different stages of disease progression concomitant with their clinical presentation. PMID:26443926

Structural modifications of the brain in acclimatization to high-altitude.

PubMed

Zhang, Jiaxing; Yan, Xiaodan; Shi, Jinfu; Gong, Qiyong; Weng, Xuchu; Liu, Yijun

2010-07-06

Adaptive changes in respiratory and cardiovascular responses at high altitude (HA) have been well clarified. However, the central mechanisms underlying HA acclimatization remain unclear. Using voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) with fractional anisotropy (FA) calculation, we investigated 28 Han immigrant residents (17-22 yr) born and raised at HA of 2616-4200 m in Qinghai-Tibetan Plateau for at least 17 years and who currently attended college at sea-level (SL). Their family migrated from SL to HA 2-3 generations ago and has resided at HA ever since. Control subjects were matched SL residents. HA residents (vs. SL) showed decreased grey matter volume in the bilateral anterior insula, right anterior cingulate cortex, bilateral prefrontal cortex, left precentral cortex, and right lingual cortex. HA residents (vs. SL) had significantly higher FA mainly in the bilateral anterior limb of internal capsule, bilateral superior and inferior longitudinal fasciculus, corpus callosum, bilateral superior corona radiata, bilateral anterior external capsule, right posterior cingulum, and right corticospinal tract. Higher FA values in those regions were associated with decreased or unchanged radial diffusivity coinciding with no change of longitudinal diffusivity in HA vs. SL group. Conversely, HA residents had lower FA in the left optic radiation and left superior longitudinal fasciculus. Our data demonstrates that HA acclimatization is associated with brain structural modifications, including the loss of regional cortical grey matter accompanied by changes in the white matter, which may underlie the physiological adaptation of residents at HA.

Diffusion imaging and transcranial magnetic stimulation assessment of transcallosal pathways in chronic stroke.

PubMed

Mang, Cameron S; Borich, Michael R; Brodie, Sonia M; Brown, Katlyn E; Snow, Nicholas J; Wadden, Katie P; Boyd, Lara A

2015-10-01

To examine the relationship of transcallosal pathway microstructure and transcallosal inhibition (TCI) with motor function and impairment in chronic stroke. Diffusion-weighted magnetic resonance imaging and transcranial magnetic stimulation (TMS) data were collected from 24 participants with chronic stroke and 11 healthy older individuals. Post-stroke motor function (Wolf Motor Function Test) and level of motor impairment (Fugl-Meyer score) were evaluated. Fractional anisotropy (FA) of transcallosal tracts between prefrontal cortices and the mean amplitude decrease in muscle activity during the ipsilateral silent period evoked by TMS over the non-lesioned hemisphere (termed NL-iSPmean) were significantly associated with level of motor impairment and motor function after stroke (p<0.05). A regression model including age, post-stroke duration, lesion volume, lesioned corticospinal tract FA, transcallosal prefrontal tract FA and NL-iSPmean accounted for 84% of variance in motor impairment (p<0.01). Both transcallosal prefrontal tract FA (ΔR(2)=0.12, p=0.04) and NL-iSPmean (ΔR(2)=0.09, p=0.04) accounted for unique variance in motor impairment level. Prefrontal transcallosal tract microstructure and TCI are each uniquely associated with motor impairment in chronic stroke. Utilizing a multi-modal approach to assess transcallosal pathways may improve our capacity to identify important neural substrates of motor impairment in the chronic phase of stroke. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

The influence of comorbid oppositional defiant disorder on white matter microstructure in attention-deficit/hyperactivity disorder.

PubMed

van Ewijk, Hanneke; Noordermeer, Siri D S; Heslenfeld, Dirk J; Luman, Marjolein; Hartman, Catharina A; Hoekstra, Pieter J; Faraone, Stephen V; Franke, Barbara; Buitelaar, Jan K; Oosterlaan, J

2016-07-01

Attention-deficit/hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD) are highly comorbid disorders. ADHD has been associated with altered white matter (WM) microstructure, though the literature is inconsistent, which may be due to differences in the in- or exclusion of participants with comorbid ODD. WM abnormalities in ODD are still poorly understood, and it is unclear whether comorbid ODD in ADHD may have confounded the current ADHD literature. Diffusion Tensor Imaging (DTI) was used to compare fractional anisotropy (FA) and mean diffusivity (MD) between ADHD patients with (n = 42) and without (n = 117) comorbid ODD. All participants were between 8-25 years and groups did not differ in mean age or gender. Follow-up analyses were conducted to examine the role of antisocial behaviour (conduct problems) on FA and MD values in both groups. Comorbid ODD in ADHD was associated with lower FA in left frontotemporal WM, which appeared independent of ADHD symptoms. FA was negatively associated with antisocial behaviour in ADHD + ODD, but not in ADHD-only. Comorbid ODD is associated with WM abnormalities in individuals with ADHD, which appears to be independent of ADHD symptoms. Altered WM microstructure in comorbid ODD may play a role in inconsistencies in the current DTI literature in ADHD. Altered development of these tracts may contribute to social-emotional and cognitive problems in children with oppositional and antisocial behaviour.

White matter microstructure within the superior longitudinal fasciculus modulates the degree of response conflict indexed by N2 in healthy adults.

PubMed

Gao, Shudan; Liu, Peng; Guo, Jialu; Zhu, Yuanqiang; Liu, Peng; Sun, Jinbo; Yang, Xuejuan; Qin, Wei

2017-12-01

Response conflict can be induced by priming multiple responses competing for control of action in trials. The N2 is one functionally-related cognitive control index for response conflict. And yet the underlying whiter matter neural substrates of inter-individual difference in conflict N2 remain unclear. So the aim of present study was to address the white matter microstructure of the N2 responsible for conflict by directly relating the amplitude cost of the event-related potential (ERP) N2 component to diffusion tensor imaging (DTI) indices in healthy subjects. Thirty healthy subjects underwent DTI scanning and electrophysiology recording during a modified Flanker task. N2 was a stimulus-locked negative ERP component. Fractional anisotropy (FA) was calculated based on DTI measures and was assumed to reflect the integrity of myelinate fiber bundles. Therefore, we tested the relationship between N2 amplitude and FA in brain white matter. Results showed that FA, an index for white matter characteristics, in the right superior longitudinal fasciculus (SLF) was significantly positively associated with N2 amplitude cost. The N2 amplitude cost also predicted response time (RT) cost in the Flanker task. Higher FA was associated with larger N2 amplitude cost, suggesting that changes in white matter integrity in the SLF may account for changes in efficient transmission of fronto-parietal modulatory conflict signals. Copyright © 2017 Elsevier B.V. All rights reserved.

Abnormal brain connectivity in first-episode psychosis: A diffusion MRI tractography study of the corpus callosum

PubMed Central

Price, Gary; Cercignani, Mara; Parker, Geoffrey J.M.; Altmann, Daniel R.; Barnes, Thomas R.E.; Barker, Gareth J.; Joyce, Eileen M.; Ron, Maria A.

2007-01-01

A model of disconnectivity involving abnormalities in the cortex and connecting white matter pathways may explain the clinical manifestations of schizophrenia. Recently, diffusion imaging tractography has made it possible to study white matter pathways in detail and we present here a study of patients with first-episode psychosis using this technique. We selected the corpus callosum for this study because there is evidence that it is abnormal in schizophrenia. In addition, the topographical organization of its fibers makes it possible to relate focal abnormalities to specific cortical regions. Eighteen patients with first-episode psychosis and 21 healthy subjects took part in the study. A probabilistic tractography algorithm (PICo) was used to study fractional anisotropy (FA). Seed regions were placed in the genu and splenium to track fiber tracts traversing these regions, and a multi-threshold approach to study the probability of connection was used. Multiple linear regressions were used to explore group differences. FA, a measure of tract coherence, was reduced in tracts crossing the genu, and to a lesser degree the splenium, in patients compared with controls. FA was also lower in the genu in females across both groups, but there was no gender-by-group interaction. The FA reduction in patients may be due to aberrant myelination or axonal abnormalities, but the similar tract volumes in the two groups suggest that severe axonal loss is unlikely at this stage of the illness. PMID:17275337

Age exacerbates HIV-associated white matter abnormalities.

PubMed

Seider, Talia R; Gongvatana, Assawin; Woods, Adam J; Chen, Huaihou; Porges, Eric C; Cummings, Tiffany; Correia, Stephen; Tashima, Karen; Cohen, Ronald A

2016-04-01

Both HIV disease and advanced age have been associated with alterations to cerebral white matter, as measured with white matter hyperintensities (WMH) on fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI), and more recently with diffusion tensor imaging (DTI). This study investigates the combined effects of age and HIV serostatus on WMH and DTI measures, as well as the relationships between these white matter measures, in 88 HIV seropositive (HIV+) and 49 seronegative (HIV-) individuals aged 23-79 years. A whole-brain volumetric measure of WMH was quantified from FLAIR images using a semi-automated process, while fractional anisotropy (FA) was calculated for 15 regions of a whole-brain white matter skeleton generated using tract-based spatial statistics (TBSS). An age by HIV interaction was found indicating a significant association between WMH and older age in HIV+ participants only. Similarly, significant age by HIV interactions were found indicating stronger associations between older age and decreased FA in the posterior limbs of the internal capsules, cerebral peduncles, and anterior corona radiata in HIV+ vs. HIV- participants. The interactive effects of HIV and age were stronger with respect to whole-brain WMH than for any of the FA measures. Among HIV+ participants, greater WMH and lower anterior corona radiata FA were associated with active hepatitis C virus infection, a history of AIDS, and higher current CD4 cell count. Results indicate that age exacerbates HIV-associated abnormalities of whole-brain WMH and fronto-subcortical white matter integrity.

Prenatal exposure to maternal and paternal depressive symptoms and white matter microstructure in children.

PubMed

El Marroun, Hanan; Zou, Runyu; Muetzel, Ryan L; Jaddoe, Vincent W; Verhulst, Frank C; White, Tonya; Tiemeier, Henning

2018-04-01

Prenatal maternal depression has been associated with multiple problems in offspring involving affect, cognition, and neuroendocrine functioning. This suggests that prenatal depression influences neurodevelopment. However, the underlying neurodevelopmental mechanism remains unclear. We prospectively assessed whether maternal depressive symptoms during pregnancy and at the child's age 3 years are related to white matter microstructure in 690 children. The association of paternal depressive symptoms with childhood white matter microstructure was assessed to evaluate genetic or familial confounding. Parental depressive symptoms were measured using the Brief Symptom Inventory. In children aged 6-9 years, we used diffusion tensor imaging to assess white matter microstructure characteristics including fractional anisotropy (FA) and mean diffusivity (MD). Exposure to maternal depressive symptoms during pregnancy was associated with higher MD in the uncinate fasciculus and to lower FA and higher MD in the cingulum bundle. No associations of maternal depressive symptoms at the child's age of 3 years with white matter characteristics were observed. Paternal depressive symptoms also showed a trend toward significance for a lower FA in the cingulum bundle. Prenatal maternal depressive symptoms were associated with higher MD in the uncinate fasciculus and the cingulum bundle. These structures are part of the limbic system, which is involved in motivation, emotion, learning, and memory. As paternal depressive symptoms were also related to lower FA in the cingulum, the observed effect may partly reflect a genetic predisposition and shared environmental family factors and to a lesser extent a specific intrauterine effect. © 2018 Wiley Periodicals, Inc.

Limbic and corpus callosum aberrations in adolescents with bipolar disorder: a tract-based spatial statistics analysis.

PubMed

Barnea-Goraly, Naama; Chang, Kiki D; Karchemskiy, Asya; Howe, Meghan E; Reiss, Allan L

2009-08-01

Bipolar disorder (BD) is a common and debilitating condition, often beginning in adolescence. Converging evidence from genetic and neuroimaging studies indicates that white matter abnormalities may be involved in BD. In this study, we investigated white matter structure in adolescents with familial bipolar disorder using diffusion tensor imaging (DTI) and a whole brain analysis. We analyzed DTI images using tract-based spatial statistics (TBSS), a whole-brain voxel-by-voxel analysis, to investigate white matter structure in 21 adolescents with BD, who also were offspring of at least one parent with BD, and 18 age- and IQ-matched control subjects. Fractional anisotropy (FA; a measure of diffusion anisotropy), trace values (average diffusivity), and apparent diffusion coefficient (ADC; a measure of overall diffusivity) were used as variables in this analysis. In a post hoc analysis, we correlated between FA values, behavioral measures, and medication exposure. Adolescents with BD had lower FA values than control subjects in the fornix, the left mid-posterior cingulate gyrus, throughout the corpus callosum, in fibers extending from the fornix to the thalamus, and in parietal and occipital corona radiata bilaterally. There were no significant between-group differences in trace or ADC values and no significant correlation between behavioral measures, medication exposure, and FA values. Significant white matter tract alterations in adolescents with BD were observed in regions involved in emotional, behavioral, and cognitive regulation. These results suggest that alterations in white matter are present early in the course of disease in familial BD.

Developmental differences in white matter architecture between boys and girls.

PubMed

Schmithorst, Vincent J; Holland, Scott K; Dardzinski, Bernard J

2008-06-01

Previous studies have found developmental differences between males and females in brain structure. During childhood and adolescence, relative white matter volume increases faster in boys than in girls. Sex differences in the development of white matter microstructure were investigated in a cohort of normal children ages 5-18 in a cross-sectional diffusion tensor imaging (DTI) study. Greater fractional anisotropy (FA) in boys was shown in associative white matter regions (including the frontal lobes), while greater FA in girls was shown in the splenium of the corpus callosum. Greater mean diffusivity (MD) in boys was shown in the corticospinal tract and in frontal white matter in the right hemisphere; greater MD in girls was shown in occipito-parietal regions and the most superior aspect of the corticospinal tract in the right hemisphere. Significant sex-age interactions on FA and MD were also shown. Girls displayed a greater rate of fiber density increase with age when compared with boys in associative regions (reflected in MD values). However, girls displayed a trend toward increased organization with age (reflected in FA values) only in the right hemisphere, while boys displayed this trend only in the left hemisphere. These results indicate differing developmental trajectories in white matter for boys and girls and the importance of taking sex into account in developmental DTI studies. The results also may have implications for the study of the relationship of brain architecture with intelligence. Copyright 2007 Wiley-Liss, Inc.

Microstructure abnormalities in adolescents with internet addiction disorder.

PubMed

Yuan, Kai; Qin, Wei; Wang, Guihong; Zeng, Fang; Zhao, Liyan; Yang, Xuejuan; Liu, Peng; Liu, Jixin; Sun, Jinbo; von Deneen, Karen M; Gong, Qiyong; Liu, Yijun; Tian, Jie

2011-01-01

Recent studies suggest that internet addiction disorder (IAD) is associated with structural abnormalities in brain gray matter. However, few studies have investigated the effects of internet addiction on the microstructural integrity of major neuronal fiber pathways, and almost no studies have assessed the microstructural changes with the duration of internet addiction. We investigated the morphology of the brain in adolescents with IAD (N = 18) using an optimized voxel-based morphometry (VBM) technique, and studied the white matter fractional anisotropy (FA) changes using the diffusion tensor imaging (DTI) method, linking these brain structural measures to the duration of IAD. We provided evidences demonstrating the multiple structural changes of the brain in IAD subjects. VBM results indicated the decreased gray matter volume in the bilateral dorsolateral prefrontal cortex (DLPFC), the supplementary motor area (SMA), the orbitofrontal cortex (OFC), the cerebellum and the left rostral ACC (rACC). DTI analysis revealed the enhanced FA value of the left posterior limb of the internal capsule (PLIC) and reduced FA value in the white matter within the right parahippocampal gyrus (PHG). Gray matter volumes of the DLPFC, rACC, SMA, and white matter FA changes of the PLIC were significantly correlated with the duration of internet addiction in the adolescents with IAD. Our results suggested that long-term internet addiction would result in brain structural alterations, which probably contributed to chronic dysfunction in subjects with IAD. The current study may shed further light on the potential brain effects of IAD.

Linear associations between clinically assessed upper motor neuron disease and diffusion tensor imaging metrics in amyotrophic lateral sclerosis.

PubMed

Woo, John H; Wang, Sumei; Melhem, Elias R; Gee, James C; Cucchiara, Andrew; McCluskey, Leo; Elman, Lauren

2014-01-01

To assess the relationship between clinically assessed Upper Motor Neuron (UMN) disease in Amyotrophic Lateral Sclerosis (ALS) and local diffusion alterations measured in the brain corticospinal tract (CST) by a tractography-driven template-space region-of-interest (ROI) analysis of Diffusion Tensor Imaging (DTI). This cross-sectional study included 34 patients with ALS, on whom DTI was performed. Clinical measures were separately obtained including the Penn UMN Score, a summary metric based upon standard clinical methods. After normalizing all DTI data to a population-specific template, tractography was performed to determine a region-of-interest (ROI) outlining the CST, in which average Mean Diffusivity (MD) and Fractional Anisotropy (FA) were estimated. Linear regression analyses were used to investigate associations of DTI metrics (MD, FA) with clinical measures (Penn UMN Score, ALSFRS-R, duration-of-disease), along with age, sex, handedness, and El Escorial category as covariates. For MD, the regression model was significant (p = 0.02), and the only significant predictors were the Penn UMN Score (p = 0.005) and age (p = 0.03). The FA regression model was also significant (p = 0.02); the only significant predictor was the Penn UMN Score (p = 0.003). Measured by the template-space ROI method, both MD and FA were linearly associated with the Penn UMN Score, supporting the hypothesis that DTI alterations reflect UMN pathology as assessed by the clinical examination.

Multimodal voxel-based meta-analysis of white matter abnormalities in obsessive-compulsive disorder.

PubMed

Radua, Joaquim; Grau, Mar; van den Heuvel, Odile A; Thiebaut de Schotten, Michel; Stein, Dan J; Canales-Rodríguez, Erick J; Catani, Marco; Mataix-Cols, David

2014-06-01

White matter (WM) abnormalities have long been suspected in obsessive-compulsive disorder (OCD) but the available evidence has been inconsistent. We conducted the first multimodal meta-analysis of WM volume (WMV) and fractional anisotropy (FA) studies in OCD. All voxel-wise studies comparing WMV or FA between patients with OCD and healthy controls in the PubMed, ScienceDirect, Google Scholar, Web of Knowledge and Scopus databases were retrieved. Manual searches were also conducted and authors were contacted soliciting additional data. Thirty-four data sets were identified, of which 22 met inclusion criteria (five of them unpublished; comprising 537 adult and pediatric patients with OCD and 575 matched healthy controls). Whenever possible, raw statistical parametric maps were also obtained from the authors. Peak and raw WMV and FA data were combined using novel multimodal meta-analytic methods implemented in effect-size signed differential mapping. Patients with OCD showed widespread WM abnormalities, but findings were particularly robust in the anterior midline tracts (crossing between anterior parts of cingulum bundle and body of corpus callosum), which showed both increased WMV and decreased FA, possibly suggesting an increase of fiber crossing in these regions. This finding was also observed when the analysis was limited to adult participants, and especially pronounced in samples with a higher proportion of medicated patients. Therefore, patients with OCD may have widespread WM abnormalities, particularly evident in anterior midline tracts, although these changes might be, at least in part, attributable to the effects of therapeutic drugs.

Mechanistic study of lead desorption during the leaching process of ion-absorbed rare earths: pH effect and the column experiment

NASA Astrophysics Data System (ADS)

Xue, Q.; Tang, J., Sr.; Chen, H.

2017-12-01

High concentrations of ammonium sulfate, often used in the in-situ mining process, can result in a decrease of pH in the environment and dissolution of rare earth metals. Ammonium sulfate can also cause desorption of toxic heavy metals, leading to environmental and human health implications. In this study, the desorption behavior and fraction changes of lead in the ion-absorbed rare earth ore were studied using batch desorption experiments and column leaching tests. Results from batch desorption experiments showed that the desorption process of lead included fast and slow stages, and followed an Elovich model well. The desorption rate and the proportion of lead content in the solution to the total lead in the soil were observed to increase with a decrease in the initial pH of the ammonium sulfate solution. The lead in soil included an acid extractable fraction, reducible fraction, oxidizable fraction, and a residual fraction, with the predominant fractions being the reducible and acid extractable fractions. 96% of the extractable fraction in soil were desorbed into solution at pH=3.0, and the content of the reducible fraction was observed to initially increase (when pH>4.0) and then decrease (when pH<4.0) with a decrease in pH. Column leaching tests indicated that the content of lead in the different fractions of soil followed the trend of reducible fraction > oxidizable fraction > acid extractable fraction > residual fraction after the simulating leaching mining process. The change in pH was also found to have a larger influence on the acid extractable and reducible fractions than the other two fractions. The proportion of the extractable fraction being leached was ca. 86%, and the reducible fraction was enriched along the migration direction of the leaching liquid. These results suggest that certain lead fractions may desorb again and contaminate the environment via acid rain, which provides significant information for environmental assessment and remediation after mining process.

MCNPX CALCULATIONS OF SPECIFIC ABSORBED FRACTIONS IN SOME ORGANS OF THE HUMAN BODY DUE TO APPLICATION OF 133Xe, 99mTc and 81mKr RADIONUCLIDES.

PubMed

Jovanovic, Z; Krstic, D; Nikezic, D; Ros, J M Gomez; Ferrari, P

2018-03-01

Monte Carlo simulations were performed to evaluate treatment doses with wide spread used radionuclides 133Xe, 99mTc and 81mKr. These different radionuclides are used in perfusion or ventilation examinations in nuclear medicine and as indicators for cardiovascular and pulmonary diseases. The objective of this work was to estimate the specific absorbed fractions in surrounding organs and tissues, when these radionuclides are incorporated in the lungs. For this purpose a voxel thorax model has been developed and compared with the ORNL phantom. All calculations and simulations were performed by means of the MCNP5/X code.

Optical Near-Field Plates

DTIC Science & Technology

2015-04-08

AFRL-OSR-VA-TR-2015-0085 OPTICAL NEAR-FILED PLATES Roberto Merlin UNIVERSITY OF MICHIGAN Final Report 04/08/2015 DISTRIBUTION A: Distribution...03-2015 Final 09/01/2009-12/31/2014 Optical Near-Field Plates FA9550-09-1-0636 erlin, Roberto, D. The University of Michigan Ann Arbor, MI 48109...distribution unlimited Optical near-field plates were designed using antisymmetric plasmon modes to generate abrupt phase changes within a fraction of a

Relationship between cardiac diffusion tensor imaging parameters and anthropometrics in healthy volunteers.

PubMed

McGill, L A; Ferreira, P F; Scott, A D; Nielles-Vallespin, S; Giannakidis, A; Kilner, P J; Gatehouse, P D; de Silva, R; Firmin, D N; Pennell, D J

2016-01-06

In vivo cardiac diffusion tensor imaging (cDTI) is uniquely capable of interrogating laminar myocardial dynamics non-invasively. A comprehensive dataset of quantative parameters and comparison with subject anthropometrics is required. cDTI was performed at 3T with a diffusion weighted STEAM sequence. Data was acquired from the mid left ventricle in 43 subjects during the systolic and diastolic pauses. Global and regional values were determined for fractional anisotropy (FA), mean diffusivity (MD), helix angle gradient (HAg, degrees/%depth) and the secondary eigenvector angulation (E2A). Regression analysis was performed between global values and subject anthropometrics. All cDTI parameters displayed regional heterogeneity. The RR interval had a significant, but clinically small effect on systolic values for FA, HAg and E2A. Male sex and increasing left ventricular end diastolic volume were associated with increased systolic HAg. Diastolic HAg and systolic E2A were both directly related to left ventricular mass and body surface area. There was an inverse relationship between E2A mobility and both age and ejection fraction. Future interpretations of quantitative cDTI data should take into account anthropometric variations observed with patient age, body surface area and left ventricular measurements. Further work determining the impact of technical factors such as strain and SNR is required.

Effects of Time-Compressed Speech Training on Multiple Functional and Structural Neural Mechanisms Involving the Left Superior Temporal Gyrus.

PubMed

Maruyama, Tsukasa; Takeuchi, Hikaru; Taki, Yasuyuki; Motoki, Kosuke; Jeong, Hyeonjeong; Kotozaki, Yuka; Nakagawa, Seishu; Nouchi, Rui; Iizuka, Kunio; Yokoyama, Ryoichi; Yamamoto, Yuki; Hanawa, Sugiko; Araki, Tsuyoshi; Sakaki, Kohei; Sasaki, Yukako; Magistro, Daniele; Kawashima, Ryuta

2018-01-01

Time-compressed speech is an artificial form of rapidly presented speech. Training with time-compressed speech (TCSSL) in a second language leads to adaptation toward TCSSL. Here, we newly investigated the effects of 4 weeks of training with TCSSL on diverse cognitive functions and neural systems using the fractional amplitude of spontaneous low-frequency fluctuations (fALFF), resting-state functional connectivity (RSFC) with the left superior temporal gyrus (STG), fractional anisotropy (FA), and regional gray matter volume (rGMV) of young adults by magnetic resonance imaging. There were no significant differences in change of performance of measures of cognitive functions or second language skills after training with TCSSL compared with that of the active control group. However, compared with the active control group, training with TCSSL was associated with increased fALFF, RSFC, and FA and decreased rGMV involving areas in the left STG. These results lacked evidence of a far transfer effect of time-compressed speech training on a wide range of cognitive functions and second language skills in young adults. However, these results demonstrated effects of time-compressed speech training on gray and white matter structures as well as on resting-state intrinsic activity and connectivity involving the left STG, which plays a key role in listening comprehension.

[Analysis of soil humus and components after 26 years' fertilization by infrared spectroscopy method].

PubMed

Zhang, Yu-Lan; Sun, Cai-Xia; Chen, Zhen-Hua; Li, Dong-Po; Liu, Xing-Bin; Chen, Li-Jun; Wu, Zhi-Jie; Du, Jian-Xiong

2010-05-01

The infrared spectrum was used to discuss structure change of soil humus and components of chemical groups in soil humic acids (HA) and fulvic acids (FA) isolated from soils in different fertilization treatment after 26 year's fertilization. The result indicated that using the infrared spectroscopy method for the determination of humus, humus fractions (HA and FA) and their structure is feasible. Fertilization affected the structure and content of soil humus and aromatization degree. After 26 years' fertilization, the infrared spectrum shapes with different treatments are similar, but the characteristic peak intensity is obviously different, which reflects the effects of different fertilization treatments on the structure and amounts of soil humus or functional groups. Compared with no fertilization, little molecule saccharides decreased and aryl-groups increased under application of inorganic fertilizer or combined application of organic and chemical fertilizer. The effect was greater in Treatment NPK and M+NPK than in Treatment M1 N and M2 N. Organic and NPK fertilizer increased the development of soil and increased soil quality to a certain extent. Results showed that organic fertilization increased aromatization degree of soil humus and humus fractions distinctly. The authors could estimate soil humus evolvement of different fertilization with infrared spectroscopy.

Lyα-emitting galaxies as a probe of reionization: large-scale bubble morphology and small-scale absorbers

NASA Astrophysics Data System (ADS)

Kakiichi, Koki; Dijkstra, Mark; Ciardi, Benedetta; Graziani, Luca

2016-12-01

The visibility of Lyα-emitting galaxies during the Epoch of Reionization is controlled by both diffuse H I patches in large-scale bubble morphology and small-scale absorbers. To investigate their impacts on Lyα transfer, we apply a novel combination of analytic modelling and cosmological hydrodynamical, radiative transfer simulations to three reionization models: (I) the `bubble' model, where only diffuse H I outside ionized bubbles is present; (II) the `web' model, where H I exists only in overdense self-shielded gas; and (III) the hybrid `web-bubble' model. The three models can explain the observed Lyα luminosity function equally well, but with very different H I fractions. This confirms a degeneracy between the ionization topology of the intergalactic medium (IGM) and the H I fraction inferred from Lyα surveys. We highlight the importance of the clustering of small-scale absorbers around galaxies. A combined analysis of the Lyα luminosity function and the Lyα fraction can break this degeneracy and provide constraints on the reionization history and its topology. Constraints can be improved by analysing the full MUV-dependent redshift evolution of the Lyα fraction of Lyman break galaxies. We find that the IGM-transmission probability distribution function is unimodal for bubble models and bimodal in web models. Comparing our models to observations, we infer that the neutral fraction at z ˜ 7 is likely to be of the order of tens of per cent when interpreted with bubble or web-bubble models, with a conservative lower limit ˜1 per cent when interpreted with web models.

Distributed transition-edge sensors for linearized position response in a phonon-mediated X-ray imaging spectrometer

NASA Astrophysics Data System (ADS)

Cabrera, Blas; Brink, Paul L.; Leman, Steven W.; Castle, Joseph P.; Tomada, Astrid; Young, Betty A.; Martínez-Galarce, Dennis S.; Stern, Robert A.; Deiker, Steve; Irwin, Kent D.

2004-03-01

For future solar X-ray satellite missions, we are developing a phonon-mediated macro-pixel composed of a Ge crystal absorber with four superconducting transition-edge sensors (TES) distributed on the backside. The X-rays are absorbed on the opposite side and the energy is converted into phonons, which are absorbed into the four TES sensors. By connecting together parallel elements into four channels, fractional total energy absorbed between two of the sensors provides x-position information and the other two provide y-position information. We determine the optimal distribution for the TES sub-elements to obtain linear position information while minimizing the degradation of energy resolution.

Electromagnetic wave absorbing properties and hyperfine interactions of Fe—Cu—Nb—Si—B nanocomposites

NASA Astrophysics Data System (ADS)

Han, Man-Gui; Guo, Wei; Wu, Yan-Hui; Liu, Min; Magundappa, L. Hadimani

2014-08-01

The Fe—Cu—Nb—Si—B alloy nanocomposite containing two ferromagnetic phases (amorphous phase and nanophase phase) is obtained by properly annealing the as-prepared alloys. High resolution transmission electron microscopy (HR-TEM) images show the coexistence of these two phases. It is found that Fe—Si nanograins are surrounded by the retained amorphous ferromagnetic phase. Mössbauer spectroscopy measurements show that the nanophase is the D03-type Fe—Si phase, which is employed to find the atomic fractions of resonant 57Fe atoms in these two phases. The microwave permittivity and permeability spectra of Fe—Cu—Nb—Si—B nanocomposite are measured in the frequency range of 0.5 GHz-10 GHz. Large relative microwave permeability values are obtained. The results show that the absorber containing the nanocomposite flakes with a volume fraction of 28.59% exhibits good microwave absorption properties. The reflection loss of the absorber is less than -10 dB in a frequency band of 1.93 GHz-3.20 GHz.

Fourier transform infrared analysis of aerosol formed in the photooxidation of 1-octene

NASA Astrophysics Data System (ADS)

Palen, Edward J.; Allen, David T.; Pandis, Spyros N.; Paulson, Suzanne; Seinfeld, John H.; Flagan, Richard C.

The chemical composition of aerosol generated in the photooxidation of 1-octene was examined using infrared microscopy interfaced with a low pressure impactor. The low pressure impactor segregated the aerosol into eight size fractions and deposited the aerosol onto ZnSe impaction substrates. The ZnSe surfaces were transparent in the mid-infrared region and therefore allowed direct analysis of the aerosol, with no extraction, using infrared microscopy. Infrared spectra of the size segregated aerosol showed strong absorbances due to ketone, alcohol, carboxylic acid and organonitrate functional groups. Absorbance features were relatively independent of particle size, with the exception of the carboxylic acid absorbances, which were found only in the largest aerosol size fractions. Molar loadings for each of the groups were estimated, based on model compound calibration standards. The molar loadings indicate that most aerosol species are multifunctional, with an average of one ketone group per molecule, an alcohol group in two of every three molecules and an organonitrate group in one of every three molecules.

Tar balls are processed, weakly absorbing, primary aerosol particles formed downwind of boreal forest fires

NASA Astrophysics Data System (ADS)

Sedlacek, A. J., III; Buseck, P. R.; Adachi, K.; Kleinman, L. I.; Onasch, T. B.; Springston, S. R.

2017-12-01

Biomass burning is a major source of light-absorbing black and brown carbonaceous aerosols Brown carbon is a poorly characterized mixture that includes tar balls (TBs), a type of carbonaceous particle unique to biomass burning. Here we describe the first atmospheric observations of the formation and evolution of TBs Aerosol particles were collected on TEM grids during individual aircraft transects at varying downwind distances from the Colockum Tarp wildland fire. The TEM images show primary particles transforming from viscous, impact-deformed particles to spherical TBs. The number fraction of TBs in the wildfire smoke plume increased from less than 5% in samples collected close to the emission source to greater than 40% after 3 hours of aging, with little change in downwind TB diameters. The TB mass fraction increased from 2% near the fire to 23±9% downwind. Single-scatter albedo determined from scattering and absorption measurements increased slightly with downwind distance. Mie calculations show this observation is consistent with weak light absorbance by TBs (m=1.56 - 0.02i) but not consistent with order-of-magnitude stronger absorption observed in different settings. The field-derived TB mass fractions reported here indicate that this particle type should be accounted for in biomass-burn emission inventories.

Interannual and geographical reproducibility of the nutritional quality of milk fat from commercial grazing flocks.

PubMed

Virto, Mailo; Bustamante, Marian; Ruiz de Gordoa, Juan Carlos; Amores, Gustavo; Fernández-Caballero, Paula N; Mandaluniz, Nerea; Arranz, Josune; Nájera, Ana I; Albisu, Marta; Pérez-Elortondo, Francisco J; Barron, Luis J R; de Renobales, Mertxe

2012-11-01

The objective of the present work was to study the differences in the fatty acid (FA) composition of raw sheep milk fat under commercial milk production conditions throughout lactation, in two consecutive years. Particular attention was placed on the C18:2cis-9,trans-11 isomer, C18:1trans-11 acid, and unsaturated FA as the feeding regimen of 10 commercial flocks of latxa dairy sheep changed from indoor feeding to part-time grazing conditions (from early spring) as traditionally practiced in the Basque Country (Northern Spain). Farms located at an altitude of between 600 and 700 m, in two different geographical areas with different rainfall were selected. Milk samples were collected monthly from late January (indoor feeding) until mid-, or end of, June (outdoor feeding), during two consecutive years. In spite of some interannual variability (most likely due to large differences in rainfall), the evolution of individual FA throughout lactation was comparable between years, indicating that it was reproducible under commercial milk production conditions. The average concentrations of C18:2cis-9,trans-11 isomer and C18:1trans-11 acid in milk from the commercial flocks increased about 200% during the transition period (end of March or early April until May), from indoor feeding (late January or early February until the end of March) to the outdoor period (early May to mid-June), remaining constant during the outdoor period (27·53 ± 9·32 μmol/g fat and 71·58 ± 20·53 μmol/g fat, respectively). Non-atherogenic FA comprised approximately 50% of all saturated FA at any time during lactation, whereas the milk atherogenicity index decreased significantly during the outdoor period. The Trolox-equivalent antioxidant capacity of the water-soluble milk fraction did not appear to be influenced by feeding management. The FA composition of cheeses made during the second year with milk from the indoor or outdoor periods reflected those of the corresponding milks. A principal components analysis clearly showed that differences in the milk FA composition were primarily due to outdoor grazing, with very little contribution from the geographical zone or the year.

Identification of Novel Genetic Determinants of Erythrocyte Membrane Fatty Acid Composition among Greenlanders.

PubMed

Andersen, Mette Korre; Jørsboe, Emil; Sandholt, Camilla Helene; Grarup, Niels; Jørgensen, Marit Eika; Færgeman, Nils Joakim; Bjerregaard, Peter; Pedersen, Oluf; Moltke, Ida; Hansen, Torben; Albrechtsen, Anders

2016-06-01

Fatty acids (FAs) are involved in cellular processes important for normal body function, and perturbation of FA balance has been linked to metabolic disturbances, including type 2 diabetes. An individual's level of FAs is affected by diet, lifestyle, and genetic variation. We aimed to improve the understanding of the mechanisms and pathways involved in regulation of FA tissue levels, by identifying genetic loci associated with inter-individual differences in erythrocyte membrane FA levels. We assessed the levels of 22 FAs in the phospholipid fraction of erythrocyte membranes from 2,626 Greenlanders in relation to single nucleotide polymorphisms genotyped on the MetaboChip or imputed. We identified six independent association signals. Novel loci were identified on chromosomes 5 and 11 showing strongest association with oleic acid (rs76430747 in ACSL6, beta (SE): -0.386% (0.034), p = 1.8x10-28) and docosahexaenoic acid (rs6035106 in DTD1, 0.137% (0.025), p = 6.4x10-8), respectively. For a missense variant (rs80356779) in CPT1A, we identified a number of novel FA associations, the strongest with 11-eicosenoic acid (0.473% (0.035), p = 2.6x10-38), and for variants in FADS2 (rs174570), LPCAT3 (rs2110073), and CERS4 (rs11881630) we replicated known FA associations. Moreover, we observed metabolic implications of the ACSL6 (rs76430747) and CPT1A (rs80356779) variants, which both were associated with altered HbA1c (0.051% (0.013), p = 5.6x10-6 and -0.034% (0.016), p = 3.1x10-4, respectively). The latter variant was also associated with reduced insulin resistance (HOMA-IR, -0.193 (0.050), p = 3.8x10-6), as well as measures of smaller body size, including weight (-2.676 kg (0.523), p = 2.4x10-7), lean mass (-1.200 kg (0.271), p = 1.7x10-6), height (-0.966 cm (0.230), p = 2.0x10-5), and BMI (-0.638 kg/m2 (0.181), p = 2.8x10-4). In conclusion, we have identified novel genetic determinants of FA composition in phospholipids in erythrocyte membranes, and have shown examples of links between genetic variants associated with altered FA membrane levels and changes in metabolic traits.

Assessment of the structural brain network reveals altered connectivity in children with unilateral cerebral palsy due to periventricular white matter lesions

PubMed Central

Pannek, Kerstin; Boyd, Roslyn N.; Fiori, Simona; Guzzetta, Andrea; Rose, Stephen E.

2014-01-01

Background Cerebral palsy (CP) is a term to describe the spectrum of disorders of impaired motor and sensory function caused by a brain lesion occurring early during development. Diffusion MRI and tractography have been shown to be useful in the study of white matter (WM) microstructure in tracts likely to be impacted by the static brain lesion. Aim The purpose of this study was to identify WM pathways with altered connectivity in children with unilateral CP caused by periventricular white matter lesions using a whole-brain connectivity approach. Methods Data of 50 children with unilateral CP caused by periventricular white matter lesions (5–17 years; manual ability classification system [MACS] I = 25/II = 25) and 17 children with typical development (CTD; 7–16 years) were analysed. Structural and High Angular Resolution Diffusion weighted Images (HARDI; 64 directions, b = 3000 s/mm2) were acquired at 3 T. Connectomes were calculated using whole-brain probabilistic tractography in combination with structural parcellation of the cortex and subcortical structures. Connections with altered fractional anisotropy (FA) in children with unilateral CP compared to CTD were identified using network-based statistics (NBS). The relationship between FA and performance of the impaired hand in bimanual tasks (Assisting Hand Assessment—AHA) was assessed in connections that showed significant differences in FA compared to CTD. Results FA was reduced in children with unilateral CP compared to CTD. Seven pathways, including the corticospinal, thalamocortical, and fronto-parietal association pathways were identified simultaneously in children with left and right unilateral CP. There was a positive relationship between performance of the impaired hand in bimanual tasks and FA within the cortico-spinal and thalamo-cortical pathways (r2 = 0.16–0.44; p < 0.05). Conclusion This study shows that network-based analysis of structural connectivity can identify alterations in FA in unilateral CP, and that these alterations in FA are related to clinical function. Application of this connectome-based analysis to investigate alterations in connectivity following treatment may elucidate the neurological correlates of improved functioning due to intervention. PMID:25003031

The aluminosilicate fraction of North Pacific manganese nodules

USGS Publications Warehouse

Bischoff, J.L.; Piper, D.Z.; Leong, K.

1981-01-01

Nine nodules collected from throughout the deep North Pacific were analyzed for their mineralogy and major-element composition before and after leaching with Chester-Hughes solution. Data indicate that the mineral phillipsite accounts for the major part (> 75%) of the aluminosilicate fraction of all nodules. It is suggested that formation of phillipsite takes place on growing nodule surfaces coupled with the oxidation of absorbed manganous ion. All the nodules could be described as ternary mixtures of amorphous iron fraction (Fe-Ti-P), manganese oxide fraction (Mn-Mg Cu-Ni), and phillipsite fraction (Al-Si-K-Na), these fractions accounting for 96% of the variability of the chemical composition. ?? 1981.

A pilot DTI analysis in patients with recent onset post-traumatic stress disorder

NASA Astrophysics Data System (ADS)

Liu, Yang; Li, Liang; Li, Baojuan; Zhang, Xi; Lu, Hongbing

2016-03-01

To explore the alteration in white matter between survivors with recent onset post-traumatic stress disorder (PTSD) and without PTSD, who survived from the same coal mine flood disaster, the diffusion tensor imaging (DTI) sequences were analyzed using DTI studio and statistical parametric mapping (SPM) packages in this paper. From DTI sequence, the fractional anisotropy (FA) value describes the degree of anisotropy of a diffusion process, while the apparent diffusion coefficient (ADC) value reflects the magnitude of water diffusion. The DTI analyses between PTSD and non-PTSD indicate lower FA values in the right caudate nucleus, right middle temporal gyrus, right fusiform gyrus, and right superior temporal gyrus, and higher ADC values in the right superior temporal gyrus and right corpus callosum of the subjects with PTSD. These results are partly in line with our previous volume and cortical thickness analyses, indicating the importance of multi-modality analysis for PTSD.

[Brain structure analysis for patients with antisocial personality disorder by MRI].

PubMed

Jiang, Weixiong; Liao, Jian; Liu, Huasheng; Huang, Renzhi; Li, Yongfan; Wang, Wei

2015-02-01

To investigate the structural abnormalities of brain in patients with antisocial personality disorder (ASPD) but without alcoholism and drug abuse. Volunteers from Hunan Reformatory (n=36) and the matched healthy subjects (n=26) were examined by high-spatial resolution magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI). Voxel-based morphometry and fractional anisotropy (FA) maps were generated for each subject to reveal structural abnormalities in patients with ASPD. Compared with the healthy controls, ASPD patients showed significantly higher gray matter volumes in the inferior parietal lobule (P≤0.001, uncorrected), white matter volumes in the precuneus (P≤0.001, uncorrected), FA in the left lingual gyrus, bilateral precuneus, right superior frontal gyrus and right middle temporal gyrus (P≤0.01, uncorrected). Our results revealed the abnormal neuroanatomical features in ASPD patients, which might be related to the external behavioral traits in ASPD patients.

Alterations in fatty acid metabolism in response to obesity surgery combined with dietary counseling

PubMed Central

Walle, P; Takkunen, M; Männistö, V; Vaittinen, M; Käkelä, P; Ågren, J; Schwab, U; Lindström, J; Tuomilehto, J; Uusitupa, M; Pihlajamäki, J

2017-01-01

Background: The effects of obesity surgery on serum and adipose tissue fatty acid (FA) profile and FA metabolism may modify the risk of obesity-related diseases. Methods: We measured serum (n=122) and adipose tissue (n=24) FA composition and adipose tissue mRNA expression of genes regulating FA metabolism (n=100) in participants of the Kuopio Obesity Surgery Study (KOBS, age 47.2±8.7 years, BMI 44.6±6.0, 40 men, 82 women) before and one year after obesity surgery. As part of the surgery protocol, all the subjects were instructed to add sources of unsaturated fatty acids, such as rapeseed oil and fatty fish, into their diet. The results were compared with changes in serum FA composition in 122 subjects from the Finnish Diabetes Prevention study (DPS) (age 54.3±7.1 years, BMI 32.2±4.6, 28 men, 94 women). Results: The proportion of saturated FAs decreased and the proportion of n-3 and n-6 FAs increased in serum triglycerides after obesity surgery (all P<0.002). Weight loss predicted changes in quantitative amounts of saturated FAs, monounsaturated FAs, n-3 and n-6 FAs in triglycerides (P<0.002 for all). Moreover, the changes in adipose tissue FAs reflected the changes in serum FAs, and some of the changes were associated with mRNA expression of elongases and desaturases in adipose tissue (all P<0.05). In line with this the estimated activity of elongase (18:1 n-7/16:1 n-7) increased significantly after obesity surgery in all lipid fractions (all P<4 × 10−7) and the increase in the estimated activity of D5D in triglycerides was associated with higher weight loss (r=0.415, P<2 × 10−6). Changes in serum FA profile were similar after obesity surgery and lifestyle intervention, except for the change in the absolute amounts of n-3 FAs between the two studies (P=0.044). Conclusions: Beneficial changes in serum and adipose tissue FAs after obesity surgery could be associated with changes in endogenous metabolism and diet. PMID:28869586

Consecutive assessment of FA and ADC values of normal lumbar nerve roots from the junction of the dura mater.

PubMed

Miyagi, Ryo; Sakai, Toshinori; Yamabe, Eiko; Yoshioka, Hiroshi

2015-06-27

Diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) are widely used in the evaluation of the central nervous system and recently have been reported as a potential tool for diagnosis of the peripheral nerve or the lumbar nerve entrapment. The purpose of this study was to evaluate consecutive changes in apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values of normal lumbar nerve roots from the junction of the dura mater. The lumbar spinal nerves were examined in 6 male healthy volunteers (mean age, 35 years) with no experiences of sciatica, with a 3.0-T MR unit using a five-element phased-array surface coil. DTI was performed with the following imaging parameters: 11084.6/73.7 ms for TR/TE; b-value, 800 s/mm2; MPG, 33 directions; slice thickness, 1.5 mm; and total scan time, 7 min 35 s. ADC and FA values at all consecutive points along the L4, L5 and S1 nerves were quantified on every 1.5 mm slice from the junction of the dura mater using short fiber tracking. ADC values of all L4, 5, and S1 nerve roots decreased linearly up to 15 mm from the dura junction and was constant distally afterward. ADC values in the proximal portion demonstrated S1 > L5 > L4 (p < 0.05). On the other hand, FA values increased linearly up to 15 mm from the dura junction, and was constant distally afterward. FA values in the proximal portion showed L4 > L5 > S1 (p < 0.05). Our study demonstrated that ADC and FA values of each L4, 5, and S1 at the proximal portion from the junction of the dura matter changed linearly. It would be useful to know the normal profile of DTI values by location of each nerve root so that we can detect subtle abnormalities in each nerve root.

The Dorsal Rather than Ventral Pathway Better Reflects Individual Syntactic Abilities in Second Language

PubMed Central

Yamamoto, Kayako; Sakai, Kuniyoshi L.

2016-01-01

The left inferior frontal gyrus (IFG) has been reported to be critically involved in syntactic processing, not only in first language (L1), but in second language (L2). Indeed, the leftward lateralization of the IFG has been shown to be correlated with the performance of a syntactic task in L2. Given that posterior language-related regions are systematically connected with the left IFG, the next question is which of the dorsal and ventral pathways is more critical to the individual syntactic abilities in L2. Here we used diffusion magnetic resonance imaging (MRI) and tractography with newly developed semi-automatic methods of defining seeds and selecting regions of interest (ROIs). We calculated mean thickness and fractional anisotropy (FA) in each ROI for the arcuate fasciculus (Arcuate) of the dorsal pathway, as well as for the inferior fronto-occipital fasciculus (IFOF) of the ventral pathway. In Experiment I, we performed partial correlation analyses between FA and the accuracy of the syntactic task, removing the effects of the accuracy of a spelling task, gender, and handedness. Among the two pathways in each hemisphere, only FA of the left Arcuate was significantly correlated with individual accuracy of the syntactic task. In Experiment II, we recruited monozygotic twins and examined to what extent their L2 abilities and their structural properties were similar. Within twin pairs, the highest significant correlation was observed for reaction times of the spelling task, while the correlation for the accuracy of the syntactic task was marginal; these two correlation coefficients were significantly different. Moreover, the thickness of the left Arcuate was highly correlated within pairs, while its FA, as well as the thickness/FA in the ventral pathways, was not significantly correlated. The correlation coefficient for the thickness of the left Arcuate was significantly larger than that of the left IFOF. These results suggest that the thickness of the left Arcuate is more associated with the shared genetic/environmental factors, whereas both of mutually correlated FA in the left Arcuate and individual syntactic abilities in L2 may be less prone to these shared factors. PMID:27378889

Alterations in fatty acid metabolism in response to obesity surgery combined with dietary counseling.

PubMed

Walle, P; Takkunen, M; Männistö, V; Vaittinen, M; Käkelä, P; Ågren, J; Schwab, U; Lindström, J; Tuomilehto, J; Uusitupa, M; Pihlajamäki, J

2017-09-04

The effects of obesity surgery on serum and adipose tissue fatty acid (FA) profile and FA metabolism may modify the risk of obesity-related diseases. We measured serum (n=122) and adipose tissue (n=24) FA composition and adipose tissue mRNA expression of genes regulating FA metabolism (n=100) in participants of the Kuopio Obesity Surgery Study (KOBS, age 47.2±8.7 years, BMI 44.6±6.0, 40 men, 82 women) before and one year after obesity surgery. As part of the surgery protocol, all the subjects were instructed to add sources of unsaturated fatty acids, such as rapeseed oil and fatty fish, into their diet. The results were compared with changes in serum FA composition in 122 subjects from the Finnish Diabetes Prevention study (DPS) (age 54.3±7.1 years, BMI 32.2±4.6, 28 men, 94 women). The proportion of saturated FAs decreased and the proportion of n-3 and n-6 FAs increased in serum triglycerides after obesity surgery (all P<0.002). Weight loss predicted changes in quantitative amounts of saturated FAs, monounsaturated FAs, n-3 and n-6 FAs in triglycerides (P<0.002 for all). Moreover, the changes in adipose tissue FAs reflected the changes in serum FAs, and some of the changes were associated with mRNA expression of elongases and desaturases in adipose tissue (all P<0.05). In line with this the estimated activity of elongase (18:1 n-7/16:1 n-7) increased significantly after obesity surgery in all lipid fractions (all P<4 × 10 -7 ) and the increase in the estimated activity of D5D in triglycerides was associated with higher weight loss (r=0.415, P<2 × 10 -6 ). Changes in serum FA profile were similar after obesity surgery and lifestyle intervention, except for the change in the absolute amounts of n-3 FAs between the two studies (P=0.044). Beneficial changes in serum and adipose tissue FAs after obesity surgery could be associated with changes in endogenous metabolism and diet.

Differences in Gaussian diffusion tensor imaging and non-Gaussian diffusion kurtosis imaging model-based estimates of diffusion tensor invariants in the human brain.

PubMed

Lanzafame, S; Giannelli, M; Garaci, F; Floris, R; Duggento, A; Guerrisi, M; Toschi, N

2016-05-01

An increasing number of studies have aimed to compare diffusion tensor imaging (DTI)-related parameters [e.g., mean diffusivity (MD), fractional anisotropy (FA), radial diffusivity (RD), and axial diffusivity (AD)] to complementary new indexes [e.g., mean kurtosis (MK)/radial kurtosis (RK)/axial kurtosis (AK)] derived through diffusion kurtosis imaging (DKI) in terms of their discriminative potential about tissue disease-related microstructural alterations. Given that the DTI and DKI models provide conceptually and quantitatively different estimates of the diffusion tensor, which can also depend on fitting routine, the aim of this study was to investigate model- and algorithm-dependent differences in MD/FA/RD/AD and anisotropy mode (MO) estimates in diffusion-weighted imaging of human brain white matter. The authors employed (a) data collected from 33 healthy subjects (20-59 yr, F: 15, M: 18) within the Human Connectome Project (HCP) on a customized 3 T scanner, and (b) data from 34 healthy subjects (26-61 yr, F: 5, M: 29) acquired on a clinical 3 T scanner. The DTI model was fitted to b-value =0 and b-value =1000 s/mm(2) data while the DKI model was fitted to data comprising b-value =0, 1000 and 3000/2500 s/mm(2) [for dataset (a)/(b), respectively] through nonlinear and weighted linear least squares algorithms. In addition to MK/RK/AK maps, MD/FA/MO/RD/AD maps were estimated from both models and both algorithms. Using tract-based spatial statistics, the authors tested the null hypothesis of zero difference between the two MD/FA/MO/RD/AD estimates in brain white matter for both datasets and both algorithms. DKI-derived MD/FA/RD/AD and MO estimates were significantly higher and lower, respectively, than corresponding DTI-derived estimates. All voxelwise differences extended over most of the white matter skeleton. Fractional differences between the two estimates [(DKI - DTI)/DTI] of most invariants were seen to vary with the invariant value itself as well as with MK/RK/AK values, indicating substantial anatomical variability of these discrepancies. In the HCP dataset, the median voxelwise percentage differences across the whole white matter skeleton were (nonlinear least squares algorithm) 14.5% (8.2%-23.1%) for MD, 4.3% (1.4%-17.3%) for FA, -5.2% (-48.7% to -0.8%) for MO, 12.5% (6.4%-21.2%) for RD, and 16.1% (9.9%-25.6%) for AD (all ranges computed as 0.01 and 0.99 quantiles). All differences/trends were consistent between the discovery (HCP) and replication (local) datasets and between estimation algorithms. However, the relationships between such trends, estimated diffusion tensor invariants, and kurtosis estimates were impacted by the choice of fitting routine. Model-dependent differences in the estimation of conventional indexes of MD/FA/MO/RD/AD can be well beyond commonly seen disease-related alterations. While estimating diffusion tensor-derived indexes using the DKI model may be advantageous in terms of mitigating b-value dependence of diffusivity estimates, such estimates should not be referred to as conventional DTI-derived indexes in order to avoid confusion in interpretation as well as multicenter comparisons. In order to assess the potential and advantages of DKI with respect to DTI as well as to standardize diffusion-weighted imaging methods between centers, both conventional DTI-derived indexes and diffusion tensor invariants derived by fitting the non-Gaussian DKI model should be separately estimated and analyzed using the same combination of fitting routines.

Hypo-Fractionated Conformal Radiation Therapy to the Tumor Bed After Segmental Mastectomy

DTIC Science & Technology

2005-07-01

induration before RT, related to the severe kyphosis, secondary to osteoporosis. In the fourth surgery . Cosmetic results were rated as "good/excellent...Fisher B, Ore L. On the underutilization of breast-conserving 20. Abner AL, Recht A, Vicini FA, et at. Cosmetic results after surgery for the treatment of...conservative breast surgery and radio- sociated with optimal cosmetic results when performing par- therapy: Results from a randomised trial. Radiother Oncol

Application of a novel sorting system for equine mesenchymal stem cells (MSCs)

PubMed Central

Radtke, Catherine L.; Nino-Fong, Rodolfo; Esparza Gonzalez, Blanca P.; McDuffee, Laurie A.

2014-01-01

The objective of this study was to validate non-equilibrium gravitational field-flow fractionation (GrFFF), an immunotag-less method of sorting mesenchymal stem cells (MSCs) into subpopulations, for use with MSCs derived from equine muscle tissue, periosteal tissue, bone marrow, and adipose tissue. Cells were collected from 6 young, adult horses, postmortem. Cells were isolated from left semitendinosus muscle tissue, periosteal tissue from the distomedial aspect of the right tibia, bone marrow aspirates from the fourth and fifth sternebrae, and left supragluteal subcutaneous adipose tissue. Aliquots of 800 × 103 MSCs from each tissue source were separated and injected into a ribbon-like capillary device by continuous flow (GrFFF proprietary system). Cells were sorted into 6 fractions and absorbencies [optical density (OD)] were read. Six fractions from each of the 6 aliquots were then combined to provide pooled fractions that had adequate cell numbers to seed at equal concentrations into assays. Equine muscle tissue-derived, periosteal tissue-derived, bone marrow-derived, and adipose tissue-derived mesenchymal stem cells were consistently sorted into 6 fractions that remained viable for use in further assays. Fraction 1 had more cuboidal morphology in culture when compared to the other fractions. Statistical analysis of the fraction absorbencies (OD) revealed a P-value of < 0.05 when fractions 2 and 3 were compared to fractions 1, 4, 5, and 6. It was concluded that non-equilibrium GrFFF is a valid method for sorting equine muscle tissue-derived, periosteal tissue-derived, bone marrow-derived, and adipose tissue-derived mesenchymal stem cells into subpopulations that remain viable, thus securing its potential for use in equine stem cell applications and veterinary medicine. PMID:25355998

Effectiveness of regional DTI measures in distinguishing Alzheimer's disease, MCI, and normal aging☆

PubMed Central

Nir, Talia M.; Jahanshad, Neda; Villalon-Reina, Julio E.; Toga, Arthur W.; Jack, Clifford R.; Weiner, Michael W.; Thompson, Paul M.

2013-01-01

The Alzheimer's Disease Neuroimaging Initiative (ADNI) recently added diffusion tensor imaging (DTI), among several other new imaging modalities, in an effort to identify sensitive biomarkers of Alzheimer's disease (AD). While anatomical MRI is the main structural neuroimaging method used in most AD studies and clinical trials, DTI is sensitive to microscopic white matter (WM) changes not detectable with standard MRI, offering additional markers of neurodegeneration. Prior DTI studies of AD report lower fractional anisotropy (FA), and increased mean, axial, and radial diffusivity (MD, AxD, RD) throughout WM. Here we assessed which DTI measures may best identify differences among AD, mild cognitive impairment (MCI), and cognitively healthy elderly control (NC) groups, in region of interest (ROI) and voxel-based analyses of 155 ADNI participants (mean age: 73.5 ± 7.4; 90 M/65 F; 44 NC, 88 MCI, 23 AD). Both VBA and ROI analyses revealed widespread group differences in FA and all diffusivity measures. DTI maps were strongly correlated with widely-used clinical ratings (MMSE, CDR-sob, and ADAS-cog). When effect sizes were ranked, FA analyses were least sensitive for picking up group differences. Diffusivity measures could detect more subtle MCI differences, where FA could not. ROIs showing strongest group differentiation (lowest p-values) included tracts that pass through the temporal lobe, and posterior brain regions. The left hippocampal component of the cingulum showed consistently high effect sizes for distinguishing groups, across all diffusivity and anisotropy measures, and in correlations with cognitive scores. PMID:24179862

Regional variation of white matter development in the cat brain revealed by ex vivo diffusion MR tractography.

PubMed

Dai, Guangping; Das, Avilash; Hayashi, Emiko; Chen, Qin; Takahashi, Emi

2016-11-01

Three-dimensional reconstruction of developing fiber pathways is essential to assessing the developmental course of fiber pathways in the whole brain. We applied diffusion spectrum imaging (DSI) tractography to five juvenile ex vivo cat brains at postnatal day (P) 35, when the degree of myelination varies across brain regions. We quantified diffusion properties (fractional anisotropy [FA] and apparent diffusion coefficient [ADC]) and other measurements (number, volume, and voxel count) on reconstructed pathways for projection (cortico-spinal and thalamo-cortical), corpus callosal, limbic (cingulum and fornix), and association (cortico-cortical) pathways, and characterized regional differences in maturation patterns by assessing diffusion properties. FA values were significantly higher in cortico-cortical pathways within the right hemisphere compared to those within the left hemisphere, while the other measurements for the cortico-cortical pathways within the hemisphere did not show asymmetry. ADC values were not asymmetric in both types of pathways. Interestingly, tract count and volume were significantly larger in the left thalamo-cortical pathways compared to the right thalamo-cortical pathways. The bilateral thalamo-cortical pathways showed high FA values compared to the other fiber pathways. On the other hand, ADC values did not show any differences across pathways studied. These results demonstrate that DSI tractography successfully depicted regional variations of white matter tracts during development when myelination is incomplete. Low FA and high ADC values in the cingulum bundle suggest that the cingulum bundle is less mature than the others at this developmental stage. Copyright © 2016 ISDN. Published by Elsevier Ltd. All rights reserved.