Detoxification and immobilization of chromite ore processing residue in spinel-based glass-ceramic.

PubMed

Liao, Chang-Zhong; Tang, Yuanyuan; Lee, Po-Heng; Liu, Chengshuai; Shih, Kaimin; Li, Fangbai

2017-01-05

A promising strategy for the detoxification and immobilization of chromite ore processing residue (COPR) in a spinel-based glass-ceramic matrix is reported in this study. In the search for a more chemically durable matrix for COPR, the most critical crystalline phase for Cr immobilization was found to be a spinel solid solution with a chemical composition of MgCr 1.32 Fe 0.19 Al 0.49 O 4 . Using Rietveld quantitative X-ray diffraction analysis, we identified this final product is with the phases of spinel (3.5wt.%), diopside (5.2wt.%), and some amorphous contents (91.2wt.%). The partitioning ratio of Cr reveals that about 77% of the Cr was incorporated into the more chemically durable spinel phase. The results of Cr K-edge X-ray absorption near-edge spectroscopy show that no Cr(VI) was observed after conversion of COPR into a glass-ceramic, which indicates successful detoxification of Cr(VI) into Cr(III) in the COPR-incorporated glass-ceramic. The leaching performances of Cr 2 O 3 and COPR-incorporated glass-ceramic were compared with a prolonged acid-leaching test, and the results demonstrate the superiority of the COPR-incorporated glass-ceramic matrix in the immobilization of Cr. The overall results suggest that the use of affordable additives has potential in more reliably immobilizing COPR with a spinel-based glass-ceramic for safer disposal of this hazardous waste. Copyright © 2016 Elsevier B.V. All rights reserved.

Enhancement of the Oral Bioavailability of Fexofenadine Hydrochloride via Cremophor® El-Based Liquisolid Tablets

PubMed Central

Yehia, Soad Ali; El-Ridi, Mohamed Shafik; Tadros, Mina Ibrahim; El-Sherif, Nolwa Gamal

2015-01-01

Purpose: The current work aimed to develop promising Fexofenadine hydrochloride (FXD) liquisolid tablets able to increase its oral bioavailability and shorten time to reach maximum plasma concentrations (Tmax). Methods: Eighteen liquisolid powders were developed based on 3 variables; (i) vehicle type [Propylene glycol (PG) or Cremophor® EL (CR)], (ii) carrier [Avicel® PH102] to coat [Aerosil® 200] ratio (15, 20, 25) and (iii) FXD concentration in vehicle (30, 35, 40 %, w/w). Pre-compression studies involved identification of physicochemical interactions and FXD crystallinity (FT-IR, DSC, XRD), topographic visualization (SEM) and estimation of flow properties (angle of repose, Carr’s index, Hausner’s ratio). CR-based liquisolid powders were compressed as liquisolid tablets (LST 9 – 18) and evaluated for weight-variation, drug-content, friability-percentage, disintegration-time and drug-release. The pharmacokinetics of LST-18 was evaluated in healthy volunteers relative to Allegra® tablets. Results: Pre-compression studies confirmed FXD dispersion in vehicles, conversion to amorphous form and formation of liquisolid powders. CR-based liquisolid powders showed acceptable-to-good flow properties suitable for compaction. CR-based LSTs had appropriate physicochemical properties and short disintegration times. Release profile of LST-18 showed a complete drug release within 5 min. Conclusion: LST-18 succeeded in increasing oral FXD bioavailability by 62% and reducing Tmax to 2.16 h. PMID:26819931

Fuel Cycle System Analysis Handbook

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

Steven J. Piet; Brent W. Dixon; Dirk Gombert

2009-06-01

This Handbook aims to improve understanding and communication regarding nuclear fuel cycle options. It is intended to assist DOE, Campaign Managers, and other presenters prepare presentations and reports. When looking for information, check here. The Handbook generally includes few details of how calculations were performed, which can be found by consulting references provided to the reader. The Handbook emphasizes results in the form of graphics and diagrams, with only enough text to explain the graphic, to ensure that the messages associated with the graphic is clear, and to explain key assumptions and methods that cause the graphed results. Some ofmore » the material is new and is not found in previous reports, for example: (1) Section 3 has system-level mass flow diagrams for 0-tier (once-through), 1-tier (UOX to CR=0.50 fast reactor), and 2-tier (UOX to MOX-Pu to CR=0.50 fast reactor) scenarios - at both static and dynamic equilibrium. (2) To help inform fast reactor transuranic (TRU) conversion ratio and uranium supply behavior, section 5 provides the sustainable fast reactor growth rate as a function of TRU conversion ratio. (3) To help clarify the difference in recycling Pu, NpPu, NpPuAm, and all-TRU, section 5 provides mass fraction, gamma, and neutron emission for those four cases for MOX, heterogeneous LWR IMF (assemblies mixing IMF and UOX pins), and a CR=0.50 fast reactor. There are data for the first 10 LWR recycle passes and equilibrium. (4) Section 6 provides information on the cycle length, planned and unplanned outages, and TRU enrichment as a function of fast reactor TRU conversion ratio, as well as the dilution of TRU feedstock by uranium in making fast reactor fuel. (The recovered uranium is considered to be more pure than recovered TRU.) The latter parameter impacts the required TRU impurity limits specified by the Fuels Campaign. (5) Section 7 provides flows for an 800-tonne UOX separation plant. (6) To complement 'tornado' economic uncertainty diagrams, which show at a glance combined uncertainty information, section 9.2 has a new set of simpler graphs that show the impact on fuel cycle costs for once through, 1-tier, and 2-tier scenarios as a function of key input parameters.« less

Performance and metabolic responses of Holstein calves to supplemental chromium in colostrum and milk.

PubMed

Ghorbani, A; Sadri, H; Alizadeh, A R; Bruckmaier, R M

2012-10-01

Twenty-two newborn Holstein female calves (BW = 39.7 ± 0.40 kg) were used to investigate the effects of chromium-l-methionine (Cr-Met) supplementation of colostrum for 3d after birth and mature milk up to wk 8 on feed intake, growth performance, health status, and metabolic and endocrine traits. Calves were randomly assigned to 2 groups, each consisting of 11 animals: 1) control and 2) 0.03 mg of supplemental Cr/kg of BW(0.75). Body weight, height at withers, and hearth girth were measured weekly. Dry matter intake, rectal temperature, fecal score, and respiratory score were recorded daily. Blood samples were collected at 12, 24, and 72 h after birth, and then every week up to 8 wk. Chromium did not affect mean body weight, dry matter intake, and withers height, but it increased hearth girth and average daily gain, tended to increase final BW, and decreased feed conversion ratio. Respiration rate increased and fecal score decreased with Cr, and rectal temperature tended to decrease with Cr. No Cr × time interactions were observed for performance and health status results except for fecal score. Blood glucose, insulin, insulin-to-glucose ratio, insulin-like growth factor-I, total protein, and triiodothyronine were not affected, whereas blood β-hydroxybutyrate, nonesterified fatty acids, cholesterol, cortisol, and thyroxin were affected by Cr supplementation. Supplemental Cr-Met decreased blood β-hydroxybutyrate at 72 h and in wk 1, 3, 4, 5, and 6 and decreased blood nonesterified fatty acids at 12h and in wk 3, 4, and 5 after birth. Blood cholesterol decreased in all sampling times, except for 12h and wk 7. Chromium decreased blood cortisol at 24h and in wk 2, 4, and 8. In conclusion, the present results demonstrate the beneficial effects of colostrum and milk supplementation with Cr to improve the performance and metabolic status of newborn calves. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Gas-to-particle conversion in the particle precipitation-aided chemical vapor deposition process II. Synthesis of the perovskite oxide yttrium chromite

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

Dieten, V.E.J. van; Dekker, J.P.; Hurkmans, E.J.

1993-11-01

In the particle precipitation-aided chemical vapor deposition process, an aerosol is formed in the gas phase at elevated temperatures. The particles are deposited on a cooled substrate. Coherent layers with a controlled porosity can be obtained by a simultaneous heterogeneous reaction, which interconnects the deposited particles. The synthesis of submicrometer powder of the perovskite oxide yttrium chromite (YCrO[sub 3]) by gas to particle conversion, which is the first step of the PP-CVD process, has been investigated, and preliminary results are shown. The powders have been synthesized using yttrium trichloride vapor (YCl[sub 3]), chromium trichloride vapor (CrCl[sub 3]), and steam andmore » oxygen as reactants. The influence of the input molar ratio of the elements on the composition and characteristics of the powders has been investigated. Phase composition has been determined by X-ray diffraction (XRD). The powders have been characterized by transmission electron microscopy (TEM) and sedimentation field flow fractionation (SF[sup 3]). At a reaction temperature of 1283 K the powders consist of the chromium sesquioxide (Cr[sub 2]O[sub 3]), or a mixture of Cr[sub 2]O[sub 3] and YCrO[sub 3]. At stoichiometeric input amounts of metal chlorides and steam the formation of YCrO[sub 3] seems to be favored. 19 refs., 6 figs., 3 tabs.« less

A spectroscopic approach toward depression diagnosis: local metabolism meets functional connectivity.

PubMed

Demenescu, Liliana Ramona; Colic, Lejla; Li, Meng; Safron, Adam; Biswal, B; Metzger, Coraline Danielle; Li, Shijia; Walter, Martin

2017-03-01

Abnormal anterior insula (AI) response and functional connectivity (FC) is associated with depression. In addition to clinical features, such as severity, AI FC and its metabolism further predicted therapeutic response. Abnormal FC between anterior cingulate and AI covaried with reduced glutamate level within cingulate cortex. Recently, deficient glial glutamate conversion was found in AI in major depression disorder (MDD). We therefore postulate a local glutamatergic mechanism in insula cortex of depressive patients, which is correlated with symptoms severity and itself influences AI's network connectivity in MDD. Twenty-five MDD patients and 25 healthy controls (HC) matched on age and sex underwent resting state functional magnetic resonance imaging and magnetic resonance spectroscopy scans. To determine the role of local glutamate-glutamine complex (Glx) ratio on whole brain AI FC, we conducted regression analysis with Glx relative to creatine (Cr) ratio as factor of interest and age, sex, and voxel tissue composition as nuisance factors. We found that in MDD, but not in HC, AI Glx/Cr ratio correlated positively with AI FC to right supramarginal gyrus and negatively with AI FC toward left occipital cortex (p < 0.05 family wise error). AI Glx/Cr level was negatively correlated with HAMD score (p < 0.05) in MDD patients. We showed that the local AI ratio of glutamatergic-creatine metabolism is an underlying candidate subserving functional network disintegration of insula toward low level and supramodal integration areas, in MDD. While causality cannot directly be inferred from such correlation, our finding helps to define a multilevel network of response-predicting regions based on local metabolism and connectivity strength.

Production and carcase traits in broiler chickens given diets supplemented with inorganic trivalent chromium and an organic acid blend.

PubMed

Samanta, S; Haldar, S; Ghosh, T K

2008-03-01

1. The study was conducted to ascertain the effects of supplemental organic acids and chromium (Cr) on production and carcase traits of broiler chickens. 2. A total of 120 1-d-old broiler chicks were divided into 4 treatment groups in a 2 x 2 factorial design (each treatment group contained 6 replicates with 5 birds per replicate). 3. The diets were supplemented with an organic acid blend containing ortho-phosphoric, formic and propionic acid and calcium propionate (1 g/kg diet) and inorganic trivalent chromium (Cr(3+)) as chromic chloride hexahydrate (0.5 mg/kg diet) either independently or together as a combination for 35 d. 4. Individual supplementation of organic acids and Cr(3+) and their combination significantly improved the food conversion ratio, hot and dressed carcase weight and weight of the wholesale cuts compared to the control group of birds. 5. Organic acids, either independently or along with Cr(3+), increased total accretion of ash in carcase. Protein accretion was improved by dietary Cr(3+) and organic acid supplementation compared to the control group and a further improvement in this regard was observed when Cr(3+) and organic acid were supplemented together. Across the treatment groups meat fat content and fat accretion were lower in birds receiving dietary Cr(3+) supplementation. 6. Circulatory Cr(3+) and meat Cr(3+) concentration increased compared to the other treatment groups when Cr(3+) was supplemented to the birds. 7. It was concluded that, instead of individual supplementation, a combination of Cr(3+) and organic acids may improve the production and carcase traits of broilers more effectively presumably because of an additive effect.

Hexavalent chromium exposures during full-aircraft corrosion control.

PubMed

Carlton, Gary N

2003-01-01

Aluminum alloys used in the construction of modern aircraft are subject to corrosion. The principal means of controlling this corrosion in the U.S. Air Force are organic coatings. The organic coating system consists of a chromate conversion coat, epoxy resin primer, and polyurethane enamel topcoat. Hexavalent chromium (CrVI) is present in the conversion coat in the form of chromic acid and in the primer in the form of strontium chromate. CrVI inhalation exposures can occur when workers spray conversion coat onto bare metal and apply primer to the treated metal surface. In addition, mechanical abrasion of aircraft surfaces can generate particulates that contain chromates from previously applied primers and conversion coats. This study measured CrVI exposures during these corrosion control procedures. Mean time-weighted average (TWA) exposure to chromic acid during conversion coat treatment was 0.48 microg/m(3), below the current American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV(R)) TWA of 50 microg/m(3) for water-soluble CrVI compounds. Mean TWA exposures to strontium chromate were 5.33 microg/m(3) during mechanical abrasion and 83.8 microg/m(3) during primer application. These levels are in excess of the current ACGIH TLV-TWA of 0.5 microg/m(3) for strontium chromate. In the absence of a change from chromated to nonchromated conversion coats and primers, additional control measures are needed to reduce these exposures.

The free radical scavenger, edaravone, ameliorates delayed neuropsychological sequelae after acute carbon monoxide poisoning in rabbits.

PubMed

Qingsong, Wang; Yeming, Guan; Xuechun, Liu; Hongjuan, Liu; Jing, Wang

2013-01-01

The mechanism underlying delayed neuropsychological sequelae (DNS) after acute carbon monoxide (CO) poisoning is unclear. There are no effective treatments for DNS. As part of a new generation of antioxidants, edaravone has been reported to improve clinical outcomes in patients exhibiting ischemic strokes. There has been little data about edaravone in relationship to DNS prevention and treatment. We hypothesized that edaravone could ameliorate DNS: Here we test that hypothesis in rabbits Rabbits were randomly divided into sham control,DNS group, saline group and edaravone group. DNS model was made by intraperitoneal injection of CO. Normal saline or edaravone (1 mg/kg, twice daily, a total of one course for 14 days) was infused through the ear vein from Day 15 since the DNS model was established. Serum superoxide dismutase (SOD) activity and malondialdehyde (MDA) were measured in each group. Magnetic resonance spectroscopy (MRS) was used to examine regions of the brain for various compounds. The apoptotic index and neuronal density in the hippocampal CA1 area were also investigated. SOD activity decreased significantly and MDA content increased substantially in the DNS group and saline group when compared with the sham control (p < 0.01). Conversely, in the edaravone group, serum SOD activity significantly increased and MDA levels significantly decreased when compared with DNS and saline group (p < 0.01). In the DNS group, the spectra of H1-MRS showed an elevated Cho/Cr and Lac/Cr ratio, and a marked decrease in the NAA/Cr ratio (p < 0.01). Compared with the saline group and DNS group, the NAA/Cr ratio was significantly increased, and the Cho/Cr and Lac/Cr ratio were significantly decreased in the edaravone group (p < 0.01). The apoptotic index in the edaravone group was significantly lower than that of the DNS and saline groups (p < 0.01, respectively), while the neuronal density in edaravone group was significantly higher than that of the DNS and saline group in the hippocampal CA1 area (p < 0.01, respectively). Our present research demonstrates that edaravone could ameliorate DNS after acute carbon monoxide poisoning in rabbits. These results suggest free radicals could be involved in the underlying mechanisms of DNS. Furthermore, brain MRS shows promise as a tool for early diagnosis for DNS.

Ambient-temperature NO oxidation over amorphous CrOx-ZrO 2 mixed oxide catalysts: Significant promoting effect of ZrO 2

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

Wang, Aiyong; Guo, Yanglong; Gao, Feng

2017-03-01

Three series of Cr-based mixed oxides (Cr-Co, Cr-Fe, and Cr-Ni oxides) with high specific surface areas and amorphous textures are synthesized using a novel sol-gel method. These mixed oxides, in comparison to their pure metal oxide (CrOx, Co3O4, FeOx and NiO) counterparts, display enhanced performance for catalytic oxidation of low-concentration NO at room temperature. Over best performing catalysts, 100% NO conversion can be maintained up to 30 h of operation at a high space velocity of 45,000 ml g-1 h-1. The amorphous structure is found to be critical for these catalysts to maintain high activity and durability. Cr/M (M=Co, Femore » and Ni) molar ratio, nitrate precursor decomposition temperature and catalyst calcination temperature are important criteria for the synthesis of the highly active catalysts. This work was supported by National Basic Research Program of China (2013CB933200), National Natural Science Foundation of China (21577035, 21577034), Commission of Science and Technology of Shanghai Municipality (15DZ1205305) and 111 Project (B08021). Aiyong Wang gratefully acknowledges the China Scholarship Council for the Joint-Training Scholarship Program with the Pacific Northwest National Laboratory (PNNL). PNNL is operated for the U.S. Department of Energy (DOE) by Battelle. FG and CHFP are supported by the U.S. DOE/Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Office.« less

Effects of dietary chromium picolinate and peppermint essential oil on growth performance and blood biochemical parameters of broiler chicks reared under heat stress conditions

NASA Astrophysics Data System (ADS)

Akbari, Mohsen; Torki, Mehran

2014-08-01

A study was conducted using 240 female day-old broiler chicks to evaluate the effects of dietary chromium picolinate (CrPic), peppermint essential oil (P.mint), or their combination on growth performance and blood biochemical parameters of female broiler chicks raised under heat stress conditions (HS, 23.9 to 38 °C cycling). Average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR) were obtained from 1 to 42 days of age. Furthermore, at the end of the experiment (day 42), birds were bled to determine some blood biochemical parameters and weighed for final body weight (BW). ADFI, ADG, and BW were not influenced significantly by dietary CrPic and P.mint ( P > 0.05). A significant interaction between dietary CrPic and P.mint on FCR ( P = 0.012) was detected. FCR significantly decreased in chicks fed the diet including both CrPic and P.mint compared with the CrPic group. Significant interaction between dietary P.mint and CrPic on serum concentrations of triglycerides, glucose, and albumin were observed ( P < 0.05), but the other measured blood biochemical parameters were not statistically affected by dietary treatments ( P > 0.05). The serum concentrations of glucose, triglycerides were decreased ( P < 0.05) in broilers fed the diet including both CrPic and P.mint. Plasma chromium (Cr) content increased significantly ( P < 0.05) in birds fed the CrPic-included diet compared with the control group ( P < 0.05). From the results of the present experiment it can be concluded that dietary supplementation with combined P.mint and CrPic could have beneficial effects on some blood biochemical parameters of female chicks reared under heat stress conditions.

Effects of dietary chromium picolinate and peppermint essential oil on growth performance and blood biochemical parameters of broiler chicks reared under heat stress conditions.

PubMed

Akbari, Mohsen; Torki, Mehran

2014-08-01

A study was conducted using 240 female day-old broiler chicks to evaluate the effects of dietary chromium picolinate (CrPic), peppermint essential oil (P.mint), or their combination on growth performance and blood biochemical parameters of female broiler chicks raised under heat stress conditions (HS, 23.9 to 38 °C cycling). Average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR) were obtained from 1 to 42 days of age. Furthermore, at the end of the experiment (day 42), birds were bled to determine some blood biochemical parameters and weighed for final body weight (BW). ADFI, ADG, and BW were not influenced significantly by dietary CrPic and P.mint (P>0.05). A significant interaction between dietary CrPic and P.mint on FCR (P=0.012) was detected. FCR significantly decreased in chicks fed the diet including both CrPic and P.mint compared with the CrPic group. Significant interaction between dietary P.mint and CrPic on serum concentrations of triglycerides, glucose, and albumin were observed (P<0.05), but the other measured blood biochemical parameters were not statistically affected by dietary treatments (P>0.05). The serum concentrations of glucose, triglycerides were decreased (P<0.05) in broilers fed the diet including both CrPic and P.mint. Plasma chromium (Cr) content increased significantly (P<0.05) in birds fed the CrPic-included diet compared with the control group (P<0.05). From the results of the present experiment it can be concluded that dietary supplementation with combined P.mint and CrPic could have beneficial effects on some blood biochemical parameters of female chicks reared under heat stress conditions.

Reproducibility over a 1-month period of 1H-MR spectroscopic imaging NAA/Cr ratios in clinically stable multiple sclerosis patients.

PubMed

Mostert, J P; Blaauw, Y; Koch, M W; Kuiper, A J; Hoogduin, J M; De Keyser, J

2008-08-01

N-acetylaspartate/creatine (NAA/Cr) ratios, assessed with proton magnetic resonance spectroscopy, are increasingly used as a surrogate marker for axonal dysfunction and degeneration in multiple sclerosis (MS). The purpose of this study was to test short-time reproducibility of NAA/Cr ratios in patients with clinically stable MS. In 35 MS patients we analysed NAA/Cr ratios obtained with (1)H-MR spectroscopic imaging at the centrum semiovale either with lateral ventricles partially included (group 1; n=15) or more cranially with no ventricles included (group 2; n=20). To test short-term reproducibility of the NAA/Cr measurements, patients were scanned twice 4 weeks apart. We determined mean NAA/Cr and Cho/Cr ratios of 12 grey matter and 24 white matter voxels. Mean NAA/Cr ratios of both the white and grey matter did not change after 4 weeks. Overall 4-week reproducibility of the NAA/Cr ratio, expressed as coefficient of variation, was 4.8% for grey matter and 3.5% for white matter. Reproducibility of cranial scanning of the ventricles was slightly better than with cerebrospinal fluid included. Our study shows good short-term reproducibility of NAA/Cr ratio measurements in the centrum semiovale, which supports the reliability of this technique for longitudinal studies.

Tandem Lewis/Brønsted homogeneous acid catalysis: conversion of glucose to 5-hydoxymethylfurfural in an aqueous chromium(iii) chloride and hydrochloric acid solution

DOE PAGES

Swift, T. Dallas; Nguyen, Hannah; Anderko, Andrzej; ...

2015-07-25

Here, a kinetic model for the tandem conversion of glucose to 5-hydroxymethylfurfural (HMF) through fructose in aqueous CrCl 3–HCl solution was developed by analyzing experimental data. We show that the coupling of Lewis and Brønsted acids in a single pot overcomes equilibrium limitations of the glucose–fructose isomerization leading to high glucose conversions and identify conditions that maximize HMF yield. Adjusting the HCl/CrCl 3 concentration has a more pronounced effect on HMF yield at constant glucose conversion than that of temperature or CrCl 3 concentration. This is attributed to the interactions between HCl and CrCl 3 speciation in solution that leadsmore » to HMF yield being maximized at moderate HCl concentrations for each CrCl 3 concentration. This volcano-like behavior is accompanied with a change in the rate-limiting step from fructose dehydration to glucose isomerization as the concentration of the Brønsted acid increases. The maximum HMF yield in a single aqueous phase is only modest and appears independent of catalysts’ concentrations as long as they are appropriately balanced. However, it can be further maximized in a biphasic system. Our findings are consistent with recent studies in other tandem reactions catalyzed by different catalysts.« less

Tandem Lewis/Brønsted homogeneous acid catalysis: conversion of glucose to 5-hydoxymethylfurfural in an aqueous chromium(iii) chloride and hydrochloric acid solution

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

Swift, T. Dallas; Nguyen, Hannah; Anderko, Andrzej

Here, a kinetic model for the tandem conversion of glucose to 5-hydroxymethylfurfural (HMF) through fructose in aqueous CrCl 3–HCl solution was developed by analyzing experimental data. We show that the coupling of Lewis and Brønsted acids in a single pot overcomes equilibrium limitations of the glucose–fructose isomerization leading to high glucose conversions and identify conditions that maximize HMF yield. Adjusting the HCl/CrCl 3 concentration has a more pronounced effect on HMF yield at constant glucose conversion than that of temperature or CrCl 3 concentration. This is attributed to the interactions between HCl and CrCl 3 speciation in solution that leadsmore » to HMF yield being maximized at moderate HCl concentrations for each CrCl 3 concentration. This volcano-like behavior is accompanied with a change in the rate-limiting step from fructose dehydration to glucose isomerization as the concentration of the Brønsted acid increases. The maximum HMF yield in a single aqueous phase is only modest and appears independent of catalysts’ concentrations as long as they are appropriately balanced. However, it can be further maximized in a biphasic system. Our findings are consistent with recent studies in other tandem reactions catalyzed by different catalysts.« less

Chromium Oxidation State in Planetary Basalts: Oxygen Fugacity Indicator and Critical Variable for Cr-Spinel Stability

NASA Technical Reports Server (NTRS)

Bell, A. S.; Burger, P. V.; Le, Loan; Papike, J. J.; Jone, J.; Shearer, C. K.

2014-01-01

Cr is a ubiquitous and relatively abundant minor element in basaltic, planetary magmas. At the reduced oxidation states (

Effects of vacuum and ageing on Zr4/Cr3 based conversion coatings on aluminium alloys

NASA Astrophysics Data System (ADS)

Thirupathi, Kalaivanan; Bárczy, Pál; Vad, Kálmán; Csik, Attila; Somosvári, Béla Márton

2018-05-01

In this study, we investigate the impact of ageing and high vacuum on existing environmentally friendly Zr4/Cr3-based conversion coatings. The freshly formed coating undergoes several changes during ageing and exposure to high vacuum. Based on the present data, we propose that the coating formed over AA6082 and AA7075 alloys is sol-gel in nature, confirmed by secondary neutral mass spectroscopy (SNMS) using the depth profiling technique. Our findings reveal that there are elemental level changes that result in shrinkage of the coating. Most Zr ions in the coating are in the solute form, with lesser number of Cr and Al ions that disappear under high vacuum over a certain period of time. The remaining Cr, Zr and O atoms exist in a gelatinous state. During ageing, there is a continuous transition of ions from solute to gelatinous state. In addition, the deposition of coating ions is directly influenced by the substrates and their constituents. The extent of dissolution of aluminium in the conversion bath determines both Zr and Cr ion deposition. For a highly alloyed metal like AA7075, the dissolution rate is disturbed by copper and zinc.

Clean Metal Finishing Alternatives

DTIC Science & Technology

2006-05-01

Cr, must heat treat for hardness 4 4 Trivalent chrome Trivalent plating chemistry Varying success, some must be brush plate 3 3 Alloy plating...metals. Hard coating deposition unproven. 3 N/A Weld coating Electrospark Deposition/ Alloying (ESD/ ESA) Microarc welding Localized repair of non...Alternatives to chromate conversion coatings Al TriChrome Pretreatment (TCP)* – AnoChem TCP, Aluminescent, TCP-HF Trivalent Cr3+ conversion with Zr

Modification of Ga2O3 by an Ag-Cr core-shell cocatalyst enhances photocatalytic CO evolution for the conversion of CO2 by H2O.

PubMed

Pang, Rui; Teramura, Kentaro; Tatsumi, Hiroyuki; Asakura, Hiroyuki; Hosokawa, Saburo; Tanaka, Tsunehiro

2018-01-25

A core-shell structure of Ag-Cr dual cocatalyst loaded-Ga 2 O 3 was found to significantly enhance the formation rate of CO and selectivity toward CO evolution for the photocatalytic conversion of CO 2 where H 2 O is used as an electron donor.

Mn-Cr systematics in primitive meteorites: Insights from mineral separation and partial dissolution

NASA Astrophysics Data System (ADS)

Göpel, Christa; Birck, Jean-Louis; Galy, Albert; Barrat, Jean-Alix; Zanda, Brigitte

2015-05-01

Cr isotopic compositions have been measured on carbonaceous chondrites (CC): Tafassasset, Paris, Niger I, NWA 5958, NWA 8157 and Jbilet Winselwan. In bulk samples, the 54Cr/52Cr ratios (expressed as ε54Cr) range from 0.93 to 1.58 ε units. These values are in agreement with values characteristic for distinct petrologic types. Despite this 54Cr heterogeneity, the variability in the 53Cr/52Cr ratios (expressed as ε53Cr) of 0.2 ε units and the Mn/Cr ratios is consistent with the previous finding of an isochron in the Mn-Cr evolution diagram. The Mn/Cr ratio in CC corresponds to variable abundances of high-T condensate formed and separated at the beginning of the solar system, thus the canonical 53Mn/55Mn ratio can be defined. Based on a consistent chronology for U-Pb and Mn-Cr between the earliest objects formed in the solar nebula and the D'Orbigny angrite we define a canonical 53Mn/55Mn ratio and ε53Cri of 6.8 × 10-6 and -0.177, respectively. The internal Mn/Cr systematics in Tafassasset and Paris were studied by two approaches: leaching technique and mineral separation. Despite variable ε54Cr values (up to >30 ε) linear co-variations were found between ε53Cr and Mn/Cr ratio. The mineral separates as well as the leachates of Tafassasset fall on a common isochron indicating that (1) cooling of the Tafassasset's parent body occurred at 4563.5 ± 0.25 Ma, and that (2) 54Cr is decoupled from the other isotopes even though temperatures >900 °C have been reached during metamorphism. In the case of Paris, the leachates form an alignment with a 53Mn/55Mn ratio higher than the canonical value. This alignment is not an isochron but rather a mixing line. Based on leachates from various CM and CI, we propose the occurrence of three distinct Cr reservoirs in meteoritic material: PURE54, HIGH53 and LOW53 characterized by a ε53Cr and ε54Cr of 0 and 25,000, -2.17 and 8, and 0.5 and -151, respectively. PURE54 has already been described and is carried by highly refractory nano-spinel; HIGH53 is Mn-rich and most probably carried by sulfides in the matrix, whereas LOW53 is characterized by low Mn/Cr ratios and it is sensitive to metamorphism. This component could correspond to mineral phases such as refractory oxides and carbide. Variable mixing proportions of HIGH53 and LOW53 would explain the larger-than-expected uncertainty (MSWD of 5.5) on the CC bulk regression line. A Monte Carlo simulation allows us to evaluate the impact of the dispersion of the initial Cr isotopic ratios (as a function of variable HIGH53). The co-variation of the Mn/Cr ratio and the ε53Cr defined by the mineral separates from Paris corresponds to an age of 4566.44 +0.66/-0.75 Ma, while their ε54Cr still differ by at least 0.42 ε. This age is likely to date the segregation of forsteritic olivines (most probably from type I chondrules) from fayalitic olivines (from type II chondrules) and, given the sampling procedure by handpicking of hundreds of grains, corresponds to the average age of chondrule formation.

Takovite-aluminosilicate-Cr materials prepared by adsorption of Cr3+ from industrial effluents as catalysts for hydrocarbon oxidation reactions.

PubMed

Ciuffi, Katia J; de Faria, Emerson H; Marçal, Liziane; Rocha, Lucas A; Calefi, Paulo S; Nassar, Eduardo J; Pepe, Iuri; da Rocha, Zênis N; Vicente, Miguel A; Trujillano, Raquel; Gil, Antonio; Korili, Sophia A

2012-05-01

The catalytic efficiency of takovite-aluminosilicate-chromium catalysts obtained by adsorption of Cr(3+) ions from aqueous solutions by a takovite-aluminosilicate nanocomposite adsorbent is reported. The adsorbent was synthesized by the coprecipitation method. The catalytic activity of the final Cr-catalysts depended on the amount of adsorbed chromium. (Z)-cyclooctene conversion up to 90% with total selectivity for the epoxide was achieved when the oxidation was carried out with hydrogen peroxide, at room temperature. After five consecutive runs, the catalysts maintained high activity, although after the sixth reuse, the epoxide yields strongly decreased to 35%. The catalysts were also efficient for cyclohexane oxidation, reaching up to 18% conversion, with cyclohexanone/cyclohexanol selectivity close to 1.2. On the whole, their use as catalysts gives a very interesting application for the solids obtained by adsorption of a contaminant cation such as Cr(3+).

Production of bio-sugar and bioethanol from coffee residue (CR) by acid-chlorite pretreatment.

PubMed

Kim, Ho Myeong; Choi, Yong-Soo; Lee, Dae-Seok; Kim, Yong-Hwan; Bae, Hyeun-Jong

2017-07-01

Nowadays, coffee residue (CR) after roasting is recognized as one of the most useful resources in the world for producing the biofuel and bio-materials. In this study, we evaluated the potential of bio-sugar and bioethanol production from acid-chlorite treated CR. Notably, CR treated three times with acid-chlorite after organic solvent extraction (OSE-3), showed the high monosaccharide content, and the efficient sugar conversion yield compared to the other pretreatment conditions. The OSE-3 (6% substrate loading, w/v) can produce bio-sugar (0.568g/g OSE-3). Also, simultaneous saccharification and fermentation (SSF) produced ethanol (0.266g/g OSE-3), and showed an ethanol conversion yield of 73.8% after a 72-h reaction period. These results suggest that acid-chlorite pretreatment can improve the bio-sugar and bioethanol production of CR by removing the phenolic and brown compounds. Copyright © 2017 Elsevier Ltd. All rights reserved.

Preparation of Trivalent Chromium and Rare Earth Composite Conversion Coating on Aluminum Alloy Surface

NASA Astrophysics Data System (ADS)

Huang, Jianzhen

2018-01-01

In this paper, the surface conversion film on 6063 aluminum alloy was prepared by chemical plating process with chromium sulfate, lanthanum sulfate and sodium phosphate as film forming agent. The corrosion resistance and surface morphology of the conversion film were analyzed by pitting corrosion test of copper sulfate and SEM. The results show that when Cr2(SO4)3 is 10 g/L, La2(SO4)3 is 2 g/L, Na3PO4 is 8 g/L, pH value is 3, temperature is 40 °C, reaction time is 10 min, the corrosion resistance of the surface conversion film is the best. The conversion coating is light green, composed of Cr, La, P, Al, O and other elements.

Magnetic field effects on electron transfer reactions involving sextet-spin ( S = 5/2) intermediates generated on photoexcitation of a Cr(III)-porphyrin complex

NASA Astrophysics Data System (ADS)

Mori, Yukie; Hoshino, Mikio; Hayashi, Hisaharu

The excited trip-sextet ( 6 T 1 ) state of chloro-(3-methylimidazol)-( meso -tetraphenylporphyrinato) chromium(III) (Cr III P) is quenched by 1,1 '-dibenzyl-4,4 '-bipyridinium (BV 2+ ) in acetonitrile through electron transfer to give 5 (Cr III P .+ ) and 2 BV .+ . The intermediate is a geminate ion pair in the sextet (Sx) state 6 [ 5 (Cr III P .+ ) 2 BV .+ ], which decays through either the escape from a solvent cage to give the free ions or the spin conversion to the quartet (Qa) state followed by back electron transfer. The free ion yield ( ΦFI ) increased with increasing magnetic field from 0 to 4 T and then slightly decreased from 4 T to 10 T. These magnetic field effects are explained as follows. Under low fields where the Zeeman splitting of the spin sublevels is lower than or comparable with the electron spin dipole-dipole interaction within 5 (Cr III P .+ ), this interaction effectively induces the Sx ⇔Qa conversion of [ 5 (Cr III P .+ ) 2 BV + ] to result in low ΦFI values. Under high fields where the Zeeman splitting is larger than the dipole-dipole interaction, the Sx Qa conversion is decreased with increasing field to cause higher ΦFI values. The slight decrease in ΦFI above 4 T may be due to the Δg mechanism.

Changes in soil organic carbon and total nitrogen in croplands converted to walnut-based agroforestry systems and orchards in southeastern Loess Plateau of China.

PubMed

Lu, Sen; Meng, Ping; Zhang, Jinsong; Yin, Changjun; Sun, Shiyou

2015-11-01

Limited information is available on the effects of agroforestry system practices on soil properties in the Loess Plateau of China. Over the last decade, a vegetation restoration project has been conducted in this area by converting cropland into tree-based agroforestry systems and orchards to combat soil erosion and degradation. The objective of the present study was to determine the effects of land use conversion on soil organic carbon and total nitrogen in southeastern Loess Plateau. The experiment included three treatments: walnut intercropping system (AF), walnut orchard (WO), and traditional cropland (CR). After 7 years of continual management, soil samples were collected at 0-10, 10-30, and 30-50-cm depths for three treatments, and soil organic carbon (SOC) and total nitrogen (TN) were measured. Results showed that compared with the CR and AF treatments, WO treatment decreased both SOC and TN concentrations in the 0-50-cm soil profile. However, similar patterns of SOC and TN concentrations were observed in the AF and CR treatments across the entire profile. The SOC stocks at 0-50-cm depth were 5.42, 5.52, and 4.67 kg m(-2) for CR, AF, and WO treatments, respectively. The calculated TN stocks at 0-50-cm depth were 0.63, 0.62, and 0.57 kg m(-2) for CR, AF, and WO treatments, respectively. This result demonstrated that the stocks of SOC and TN in WO were clearly lower than those of AF and CR and that the walnut-based agroforestry system was more beneficial than walnut monoculture in terms of SOC and TN sequestration. Owing to the short-term intercropping practice, the changes in SOC and TN stocks were slight in AF compared with those in CR. However, a significant decrease in SOC and TN stocks was observed during the conversion of cropland to walnut orchard after 7 years of management. We also found that land use types had no significant effect on soil C/N ratio. These findings demonstrated that intercropping between walnut rows can potentially maintain more SOC and TN stocks than walnut monoculture and that agroforestry is a sustainable management pattern for vegetation restoration in the Loess Plateau area.

Simulation of solution phase electron transfer in a compact donor-acceptor dyad.

PubMed

Kowalczyk, Tim; Wang, Lee-Ping; Van Voorhis, Troy

2011-10-27

Charge separation (CS) and charge recombination (CR) rates in photosynthetic architectures are difficult to control, yet their ratio can make or break photon-to-current conversion efficiencies. A rational design approach to the enhancement of CS over CR requires a mechanistic understanding of the underlying electron-transfer (ET) process, including the role of the environment. Toward this goal, we introduce a QM/MM protocol for ET simulations and use it to characterize CR in the formanilide-anthraquinone dyad (FAAQ). Our simulations predict fast recombination of the charge-transfer excited state, in agreement with recent experiments. The computed electronic couplings show an electronic state dependence and are weaker in solution than in the gas phase. We explore the role of cis-trans isomerization on the CR kinetics, and we find strong correlation between the vertical energy gaps of the full simulations and a collective solvent polarization coordinate. Our approach relies on constrained density functional theory to obtain accurate diabatic electronic states on the fly for molecular dynamics simulations, while orientational and electronic polarization of the solvent is captured by a polarizable force field based on a Drude oscillator model. The method offers a unified approach to the characterization of driving forces, reorganization energies, electronic couplings, and nonlinear solvent effects in light-harvesting systems.

Glycemic control and hypoglycemia in Veterans Health Administration patients converted from glyburide to glipizide.

PubMed

Skoff, Rachel A; Waterbury, Nancee V; Shaw, Robert F; Egge, Jason A; Cantrell, Matthew

2011-11-01

In 2009, the Veterans Health Administration (VHA) released a national bulletin regarding the risk of hypoglycemia associated with the use of glyburide in elderly patients with renal dysfunction. Providers were encouraged to avoid glyburide and use glipizide in patients with a calculated creatinine clearance (CrCl) of less than 50 mL per minute. Since this initiative, many veterans were converted by their providers from glyburide to glipizide regardless of renal impairment. To (a) identify whether hemoglobin A1c remained equivalent in patients converted from glyburide to glipizide, (b) evaluate the prevalence of hypoglycemia during treatment with glyburide or glipizide, (c) compare change in glycemic control for renally impaired versus nonimpaired patients, and (d) analyze dosage conversion ratios selected by providers and measures of patient follow-up after conversion including time until A1c measurement and number of glipizide dose titrations. This was a single-center, retrospective analysis of veterans converted from glyburide to glipizide from January 1, 2008, through May 31, 2010, who had documented A1c values concurrent with glyburide and glipizide use. A 2-sided equivalence analysis was used for the primary outcome. Equivalence was defined as a change in mean A1c of ± 0.2. Hypoglycemia was defined as blood glucose of less than 70 mg per dL, symptoms of hypoglycemia, or hypoglycemia that led to a fall, loss of consciousness, emergency room visit, hospitalization, or death. The pre- to post-conversion change in rates of hypoglycemia was tested for significance using a McNemar's test. In the 141 (99.3% male, 53.9% CrCl less than 50 mL per minute, mean age = 74.0 years) patients meeting inclusion criteria between 2008-2010, the average change in A1c (+ 0.34) was nonequivalent after conversion from glyburide to glipizide (7.08% vs. 7.42%, respectively). Hypoglycemia occurred more frequently during treatment with glyburide than glipizide (31.2% vs. 12.8%, respectively, P less than 0.001). Mean dose conversion ratios were consistent with VHA recommendations (1 mg per day glyburide = 1.26- 1.55 mg per day glipizide). Conversion from glyburide to glipizide was associated with an increase in A1c, but the incidence of hypoglycemia was reduced. Results of this study are consistent with the recommendation of the American Diabetes Association and European Association for the Study of Diabetes to use second-generation sulfonylureas other than glyburide. Patients converted to glipizide should be monitored closely to adjust therapy as appropriate to maintain glycemic control.

Manganese-Chromium Isotope Systematics of Ivuna, Kainsaz and Other Carbonaceous Chondrites

NASA Technical Reports Server (NTRS)

Shukolyukov, A.; Lugmair, G. W.; Bogdanovski, O.

2003-01-01

We have shown earlier that the bulk samples of carbonaceous chondrites [CC] reveal excesses in both Cr-53 (Cr-53*) and Cr-54 (Cr-54*) as compared to the terrestrial standard value. The Cr-53/52 ratios in bulk samples of Orgueil (CI), Murray (CM), Allende (CV), and the Bencubbin/CH-like meteorite Hammadah Al Hambra 237 (HH237) are correlated with the respective Mn/Cr ratios. In contrast to CC, HH237 is characterized by a deficit of Cr-53 (-0.15 +/- 0.10(epsilon)) at a low Mn/Cr ratio of 0.07. The HH237 data point, however, falls on the CC line. Here we report new Mn-53 - Cr-53 results for the CC Kainsaz (CO) and Ivuna (CI).

Effects of dietary organic chromium and vitamin C supplementation on performance, immune responses, blood metabolites, and stress status of laying hens subjected to high stocking density.

PubMed

Mirfendereski, E; Jahanian, R

2015-02-01

The present study was carried out to investigate the effects of dietary supplementation of chromium-methionine (CrMet) and vitamin C (VC) on performance, immune response, and stress status of laying hens subjected to high stocking density. A total of 360 Hy-Line W-36 leghorn hens (at 26 wk old) were used in a 2×3×2 factorial arrangement that had 2 cage densities (5 and 7 hens per cage), 3 Cr levels (0, 500, and 1,000 ppb as CrMet), and 2 dietary VC levels (0 and 500 ppm as L-ascorbic acid). The trial lasted for 12 wk. The first 2 wk were for adaptation (26 to 28 wk of age), and the remaining 10 wk served as the main recording period. In addition to performance, immune response to Newcastle disease virus (NDV) was assessed at d 7 and 14 postvaccination. Also, the birds' stress status was evaluated by analyzing appropriate plasma metabolites. The results showed that hens in cages with higher stocking density had lower hen-day egg production, egg mass, and feed intake compared with those in normal density cages (P<0.05). Dietary CrMet supplementation caused significant increases in egg production and egg mass (P<0.01). There were significant Cr × VC interactions related to egg production and feed conversion efficiency (P<0.01); dietary CrMet supplementation was more effective in improving egg production and feed conversion ratio in VC-unsupplemented diets. Although plasma concentrations of triglycerides and high-density lipoproteins were not influenced by dietary treatments, supplemental CrMet decreased plasma cholesterol levels (P<0.05). Plasma insulin and glucose levels of hens kept at a density of 7 hens/cage were significantly higher than those of hens in normal cage density (P<0.01), and dietary CrMet supplementation decreased plasma concentrations of insulin (P<0.001) and glucose (P<0.01), with higher impacts in high stocking density-challenged hens. While high stocking density caused a marked increase in plasma corticosterone (P<0.01), both supplemental CrMet and VC decreased it to near normal levels. There were significant stocking density×Cr interactions related to plasma insulin and corticosterone concentrations (P<0.01); supplemental CrMet was more effective in lowering these hormones in high stocking density-challenged hens. The high stocking density challenge suppressed NDV antibody response (P<0.001), while dietary supplementation of CrMet improved antibody titers against NDV at d 14 post vaccination particularly in hens kept at a density of 7 hens/cage (P<0.01). From the present observations, it can be concluded that CrMet can improve laying performance largely because it alleviates harmful responses to stressful conditions. © 2015 Poultry Science Association Inc.

Dietary Chromium Picolinate Supplementation Affects Growth, Whole-Body Composition, and Gene Expression Related to Glucose Metabolism and Lipogenesis in Juvenile Blunt Snout Bream, Megalobrama amblycephala.

PubMed

Ren, Mingchun; Mokrani, Ahmed; Liang, Hualiang; Ji, Ke; Xie, Jun; Ge, Xianping; Liu, Bo

2018-01-18

An 11-week feeding trial was carried out to investigate the effects of supplemented chromium picolinate (Cr-Pic) on the growth, whole-body composition, and relative mRNA expression related to lipogenesis and glucose metabolism in juvenile blunt snout bream. Seven isonitrogenous and isoenergetic diets with graded Cr supplementation levels were fed to triplicate groups. The final weight (FW), feed conversion ratio (FCR), and specific growth rate (SGR) were improved with increasing dietary Cr supplementation levels up to 0.4 mg/kg, and thereafter showed relatively constant. However, 12.0 mg/kg dietary Cr supplementation decreased growth and feed utilization. Based on SGR and FCR, the optimal dietary Cr supplementation level for the juvenile was estimated to be 0.28 mg/kg. Significantly higher plasma insulin levels were found in juvenile fed diets with 0.4 and 0.8 mg/kg Cr supplementation compared to those fed diet sans supplemented Cr. Plasma glucose levels decreased with increasing dietary Cr supplementation, and the lowest value was remarked in the group added 3.2 mg/kg of Cr. Adding 0.4-0.8 mg/kg Cr enhanced insulin receptor substrate 1 (IRS-1), phosphoinositide-3-kinase (PI3K), and pyruvate kinase (PK) and inhibited expression of phosphoenolpyruvate carboxykinase (PEPCK), glucose-6-phosphatase (G6Pase), and glycogen synthase (GS) mRNA levels. High dietary Cr (12.0 mg/kg) supplementation resulted in high G6Pase and PEPCK expression. The highest content of whole-body lipid was remarked in fish fed with 0.4 mg/kg dietary Cr, which related to the enhanced gene expression related to lipogenesis; thereafter, mRNA levels showed a diminishing trend. These findings indicate that optimum dietary Cr-Pic supplementation has a positive effect on growth and blood glucose homeostasis by modifying the mRNA levels related to glucose metabolism and lipogenesis in juvenile blunt snout bream.

Structural and magnetic properties of hexagonal Cr1-δTe films grown on CdTe(001) by molecular beam epitaxy

NASA Astrophysics Data System (ADS)

Kanazawa, Ken; Yamawaki, Kazuma; Sekita, Naoya; Nishio, Yôtarô; Kuroda, Shinji; Mitome, Masanori; Bando, Yoshio

2015-04-01

We investigated the structural and magnetic properties of Cr1-δTe thin films grown on CdTe(001) layers by molecular beam epitaxy (MBE) with systematic variations of the ratio between Cr and Te fluxes and the substrate temperature Ts during the growth. Cr1-δTe of the hexagonal structure (hex-Cr1-δTe) was always formed irrespective of the growth conditions, but the growth orientation was different depending on the Cr/Te flux ratio and Ts. Hex-Cr1-δTe was grown in the [0001] axis in the range of small Cr/Te ratios and high Ts while it was also grown in the direction normal to the (1-102) plane at larger Cr/Te ratios or lower Ts. Hex-Cr1-δTe films grown in the both orientations show ferromagnetism, but they exhibit a clear contrast in the field dependence of perpendicular magnetization at 2 K; a square hysteretic loop in the film grown in the [0001] axis versus a round-shape loop in the film grown in the direction normal to the (1-102) plane. Moreover, the films grown in the [0001] axis at the smallest Cr/Te ratio show variations of ferromagnetic properties with Curie temperature (Tc) and the coercivity (Hc) varying according to the value of Ts.

Implementing New Non-Chromate Coatings Systems (Briefing Charts)

DTIC Science & Technology

2011-02-09

Initiate Cr6+ authorization process for continued Cr6+ use using the form, Authorization to Use Hexavalent Chromium. YES NO • Approval of...Aluminum and magnesium anodizing • Hard Chrome Plating • Type II conversion coating on aluminum alloys under chromated primer • Type II conversion coating...Elimination of Hexavalent Chromium 80% 5% 14% 1% Type II Type III Type IC Type IC Fatigue Critical 50% 50% Type II Type IC FRC-SE (JAX) Fully Integrated FRC

Radical Polymerization of Vinyl Acetate and Methyl Methacrylate Using Organochromium Initiators Complexed with Macrocyclic Polyamines

DTIC Science & Technology

1994-06-30

conversion, the increase was faster than at later stages. and therefore the steric strain enfosced by the 5gn backone dpdson Th efficiency of initation...BPOJ),- 0.25M. Cr(OAc)2jDPO, THF. 200CC IVAclo - SMK [Cr2io - [DPOJ~i 0.25M. (UI - (Cr2+’Jo (LIgl - (Cr2൒ 0 _ In the absence of any liganda, a

Reaction pathway in vapour phase hydrogenation of maleic anhydride and its esters to {gamma}-butyrolactone

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

Messori, M.; Vaccari, A.

1994-11-01

The catalytic reactivity of maleic anhydride (MA), succinic anhydride (SA) and their dimethyl esters (dimethyl maleate and dimethyl succinate) in the vapour phase hydrogenation to {gamma}-butyrolacetone (GBL) was investigated. In order to obtain general data, both a multicomponent catalyst (CAT 1: Cu/Zn/Mg/Cr = 40:5:5:50, atomic ratio %), obtained by reduction of a nonstoichiometric spinel-type precursor, and a commercial catalyst (CAT 2: Cu/Mn/Ba/Cr = 44:8:1:47, atomic ratio %) were used. The MA/GBL solution exhibited the highest GBL production, while the SA/GBL solution was converted only partially due to a competitive adsorption of GBL on the active sites, as evidenced by themore » similar reactivities observed with pure anhydrides. The best carbon balances were observed with the esters, probably the result of lowest light hydrocarbon synthesis and tar formation. With all the feedstocks, the activity of CAT 2 is higher than that of CAT 1, which, however, gives the best yield in GBL due its lower activity in the overhydrogenation and hydrogenolysis reaction. It was found that n-butanol (BuOH) and butyric acid (BuA) derived mainly from GBL. On this basis, the reactivities of the main products observed were investigated separately, confirming the stability of tetrahydrofuran (THF), which reacted only at high temperature with low conversions to ethanol. On the other hand, GBL gave rise to overhydrogenation and/or hydrogenolysis, with high conversion (mainly with CAT 2), confirming its key role in both reactions. Furthermore, the formation in the catalytic tests with BuA and BuOH of n-butanal, notwithstanding the high H{sub 2}/organic ratio, implies that it is the main intermediate in the hydrogenolysis reactions. A new reaction scheme is proposed, pointing out the key role of GBL as the {open_quotes}intersection{close_quotes} of two possible reaction pathways, giving rise to THF or overhydrogenation and hydrogenolysis products, respectively. 44 refs., 4 figs., 6 tabs.« less

Candle soot nanoparticles-polydimethylsiloxane composites for laser ultrasound transducers

NASA Astrophysics Data System (ADS)

Chang, Wei-Yi; Huang, Wenbin; Kim, Jinwook; Li, Sibo; Jiang, Xiaoning

2015-10-01

Generation of high power laser ultrasound strongly demands the advanced materials with efficient laser energy absorption, fast thermal diffusion, and large thermoelastic expansion capabilities. In this study, candle soot nanoparticles-polydimethylsiloxane (CSNPs-PDMS) composite was investigated as the functional layer for an optoacoustic transducer with high-energy conversion efficiency. The mean diameter of the collected candle soot carbon nanoparticles is about 45 nm, and the light absorption ratio at 532 nm wavelength is up to 96.24%. The prototyped CSNPs-PDMS nano-composite laser ultrasound transducer was characterized and compared with transducers using Cr-PDMS, carbon black (CB)-PDMS, and carbon nano-fiber (CNFs)-PDMS composites, respectively. Energy conversion coefficient and -6 dB frequency bandwidth of the CSNPs-PDMS composite laser ultrasound transducer were measured to be 4.41 × 10-3 and 21 MHz, respectively. The unprecedented laser ultrasound transduction performance using CSNPs-PDMS nano-composites is promising for a broad range of ultrasound therapy applications.

Magnetic interaction reversal in watermelon nanostructured Cr-doped Fe nanoclusters

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

Kaur, Maninder; Qiang, You, E-mail: youqiang@uidaho.edu; Dai, Qilin

2013-11-11

Cr-doped core-shell Fe/Fe-oxide nanoclusters (NCs) were synthesized at varied atomic percentages of Cr from 0 at. % to 8 at. %. The low concentrations of Cr (<10 at. %) were selected in order to inhibit the complete conversion of the Fe-oxide shell to Cr{sub 2}O{sub 3} and the Fe core to FeCr alloy. The magnetic interaction in Fe/Fe-oxide NCs (∼25 nm) can be controlled by antiferromagnetic Cr-dopant. We report the origin of σ-FeCr phase at very low Cr concentration (2 at. %) unlike in previous studies, and the interaction reversal from dipolar to exchange interaction in watermelon-like Cr-doped core-shell NCs.

Alkaline electrochemical advanced oxidation process for chromium oxidation at graphitized multi-walled carbon nanotubes.

PubMed

Xue, Yudong; Zheng, Shili; Sun, Zhi; Zhang, Yi; Jin, Wei

2017-09-01

Alkaline electrochemical advanced oxidation processes for chromium oxidation and Cr-contaminated waste disposal were reported in this study. The highly graphitized multi-walled carbon nanotubes g-MWCNTs modified electrode was prepared for the in-situ electrochemical generation of HO 2 - . RRDE test results illustrated that g-MWCNTs exhibited much higher two-electron oxygen reduction activity than other nanocarbon materials with peak current density of 1.24 mA cm -2 , %HO 2 - of 77.0% and onset potential of -0.15 V (vs. Hg/HgO). It was originated from the highly graphitized structure and good electrical conductivity as illustrated from the Raman, XRD and EIS characterizations, respectively. Large amount of reactive oxygen species (HO 2 - and ·OH) were in-situ electro-generated from the two-electron oxygen reduction and chromium-induced alkaline electro-Fenton-like reaction. The oxidation of Cr(III) was efficiently achieved within 90 min and the conversion ratio maintained more than 95% of the original value after stability test, offering an efficient and green approach for the utilization of Cr-containing wastes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Brain metabolite changes in patients with type 2 diabetes and cerebral infarction using proton magnetic resonance spectroscopy.

PubMed

Zhang, Min; Sun, Xinhai; Zhang, Zhengjun; Meng, Qiang; Wang, Yuzhong; Chen, Jing; Ma, Xueqin; Geng, Houfa; Sun, Lin

2014-01-01

The aim of this study was to investigate the possible brain metabolic alterations in patients with type 2 diabetes mellitus (T2DM) and cerebral infarction (DMCI) using proton magnetic resonance spectroscopy (MRS). Thirty-four patients with T2DM and DMCI were scanned together with 33 patients with nondiabetic cerebral infarction (NDCI) on a 1.5-T MRI/MRS imager. Voxels were placed in the infarcted area and the contralateral normal area in the basal ganglia. N-acetylaspartate (NAA)/creatine (Cr), choline (Cho)/Cr, and lactate (Lac)/Cr ratios were calculated. Cerebral NAA/Cr ratios in the infarcted area were lower than those in the contralateral normal area of the NDCI group. There was a significant decrease in NAA/Cr in the infarcted area of the DMCI group as compared with the infarcted area of the NDCI group. NAA/Cr ratios in the contralateral normal area of DMCI group were lower than those of the NDCI group. Lac/Cr ratios were increased in the infarcted area of both the DMCI group and NDCI group, and Lac/Cr ratios tended to be higher in the infarcted area of the DMCI group than those of the NDCI group. Glycosylated hemoglobin (HbA1c) levels were negatively correlated with NAA/Cr ratios. The study suggested that the metabolite changes were different between DMCI patients and NDCI patients, which may provide important information in the treatment of DMCI.

Epitaxial Bi2 FeCrO6 Multiferroic Thin Film as a New Visible Light Absorbing Photocathode Material.

PubMed

Li, Shun; AlOtaibi, Bandar; Huang, Wei; Mi, Zetian; Serpone, Nick; Nechache, Riad; Rosei, Federico

2015-08-26

Ferroelectric materials have been studied increasingly for solar energy conversion technologies due to the efficient charge separation driven by the polarization induced internal electric field. However, their insufficient conversion efficiency is still a major challenge. Here, a photocathode material of epitaxial double perovskite Bi(2) FeCrO(6) multiferroic thin film is reported with a suitable conduction band position and small bandgap (1.9-2.1 eV), for visible-light-driven reduction of water to hydrogen. Photoelectrochemical measurements show that the highest photocurrent density up to -1.02 mA cm(-2) at a potential of -0.97 V versus reversible hydrogen electrode is obtained in p-type Bi(2) FeCrO(6) thin film photocathode grown on SrTiO(3) substrate under AM 1.5G simulated sunlight. In addition, a twofold enhancement of photocurrent density is obtained after negatively poling the Bi(2) FeCrO(6) thin film, as a result of modulation of the band structure by suitable control of the internal electric field gradient originating from the ferroelectric polarization in the Bi(2) FeCrO(6) films. The findings validate the use of multiferroic Bi(2) FeCrO(6) thin films as photocathode materials, and also prove that the manipulation of internal fields through polarization in ferroelectric materials is a promising strategy for the design of improved photoelectrodes and smart devices for solar energy conversion. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of stress ratio on the temperature-dependent high-cycle fatigue properties of alloy steels

NASA Astrophysics Data System (ADS)

Lü, Zhi-yang; Wan, Ao-shuang; Xiong, Jun-jiang; Li, Kuang; Liu, Jian-zhong

2016-12-01

This paper addresses the effects of stress ratio on the temperature-dependent high-cycle fatigue (HCF) properties of alloy steels 2CrMo and 9CrCo, which suffer from substantial vibrational loading at small stress amplitude, high stress ratio, and high frequency in the high-temperature environments in which they function as blade and rotor spindle materials in advanced gas or steam turbine engines. Fatigue tests were performed on alloy steels 2CrMo and 9CrCo subjected to constant-amplitude loading at four stress ratios and at four and three temperatures, respectively, to determine their temperature-dependent HCF properties. The interaction mechanisms between high temperature and stress ratio were deduced and compared with each other on the basis of the results of fractographic analysis. A phenomenological model was developed to evaluate the effects of stress ratio on the temperature-dependent HCF properties of alloy steels 2CrMo and 9CrCo. Good correlation was achieved between the predictions and actual experiments, demonstrating the practical and effective use of the proposed method.

Type I Cosmic Spherules: Key to a Major, But Poorly Sampled, Asteroid Population?

NASA Technical Reports Server (NTRS)

Nyquist, L. E.

1999-01-01

Herzog et al. have determined Fe, Ni, and Cr abundances in Type I cosmic spherules recovered from the deep sea, and also the isotopic fractionation of these elements during passage of the spherules through the terrestrial atmosphere. Isotopic fractionation for all three elements is typically large, approx. 16%/amu, corresponding to evaporative mass losses of approx. 80 - 85%, assuming Rayleigh distillation from an open system. The corrected, pre-atmospheric, Cr/Ni and Fe/Ni ratios, are compared to ratios in bulk chondrites and chondritic metal. Although the calculated pre-atmospheric Fe/Ni ratio for the spherules is relatively constant at 19 +/- 4 (sigma(sub mean)) the calculated pre-atmospheric Cr/Ni ratios vary by about two orders of magnitude. The Cr/Ni ratios are thus powerful discriminators for possible modes of origin of the spherules. For example, iron meteorites typically have low Cr contents and low Cr/Ni ratios, less or = 3 x 10(exp -4). Thus, Type I spherules do not appear to be ablation products of iron meteorites, in contrast to an earlier suggestion.

Estimation of Daily Proteinuria in Patients with Amyloidosis by Using the Protein-To-Creatinine ratio in Random Urine Samples.

PubMed

Talamo, Giampaolo; Mir Muhammad, A; Pandey, Manoj K; Zhu, Junjia; Creer, Michael H; Malysz, Jozef

2015-02-11

Measurement of daily proteinuria in patients with amyloidosis is recommended at the time of diagnosis for assessing renal involvement, and for monitoring disease activity. Renal involvement is usually defined by proteinuria >500 mg/day. We evaluated the accuracy of the random urine protein-to-creatinine ratio (Pr/Cr) in predicting 24 hour proteinuria in patient with amyloidosis. We compared results of random urine Pr/Cr ratio and concomitant 24-hour urine collections in 44 patients with amyloidosis. We found a strong correlation (Spearman's ρ=0.874) between the Pr/Cr ratio and the 24 hour urine protein excretion. For predicting renal involvement, the optimal cut-off point of the Pr/Cr ratio was 715 mg/g. The sensitivity and specificity for this point were 91.8% and 95.5%, respectively, and the area under the curve value was 97.4%. We conclude that the random urine Pr/Cr ratio could be useful in the screening of renal involvement in patients with amyloidosis. If validated in a prospective study, the random urine Pr/Cr ratio could replace the 24 hour urine collection for the assessment of daily proteinuria and presence of nephrotic syndrome in patients with amyloidosis.

New conversion factors between human and automatic readouts of the CDMAM phantom for CR systems

NASA Astrophysics Data System (ADS)

Hummel, Johann; Homolka, Peter; Osanna-Elliot, Angelika; Kaar, Marcus; Semtrus, Friedrich; Figl, Michael

2016-03-01

Mammography screenings demand for profound image quality (IQ) assessment to guarantee their screening success. The European protocol for the quality control of the physical and technical aspects of mammography screening (EPQCM) suggests a contrast detail phantom such as the CDMAM phantom to evaluate IQ. For automatic evaluation a software is provided by the EUREF. As human and automatic readouts differ systematically conversion factors were published by the official reference organisation (EUREF). As we experienced a significant difference for these factors for Computed Radiography (CR) systems we developed an objectifying analysis software which presents the cells including the gold disks randomly in thickness and rotation. This allows to overcome the problem of an inevitable learning effect where observers know the position of the disks in advance. Applying this software, 45 computed radiography (CR) systems were evaluated and the conversion factors between human and automatic readout determined. The resulting conversion factors were compared with the ones resulting from the two methods published by EUREF. We found our conversion factors to be substantially lower than those suggested by EUREF, in particular 1.21 compared to 1.42 (EUREF EU method) and 1.62 (EUREF UK method) for 0.1 mm, and 1.40 compared to 1.73 (EUREF EU) and 1.83 (EUREF UK) for 0.25 mm disc diameter, respectively. This can result in a dose increase of up to 90% using either of these factors to adjust patient dose in order to fulfill image quality requirements. This suggests the need of an agreement on their proper application and limits the validity of the assessment methods. Therefore, we want to stress the need for clear criteria for CR systems based on appropriate studies.

Influence of fuel-nitrate ratio on the structural and magnetic properties of Fe and Cr based spinels prepared by solution self combustion method

NASA Astrophysics Data System (ADS)

Sijo, A. K.

2017-11-01

In this study, we report the synthesis of nano-sized CoCrFeO4 and NiCrFeO4 using the solution self combustion method and the variation in the magnetic and structural properties with different fuel to nitrate ratios-fuel lean, fuel rich and stoichiometric. Citric acid is used as the fuel. XRD analysis of the samples confirms the formation of pure spinel phased nanoparticles in fuel rich and stoichiometric cases. But CoCrFeO4 and NiCrFeO4 samples prepared under the fuel lean condition show the presence of a small amount of impurity phases: α-Ni in fuel lean NiCrFeO4 and α-Co in fuel lean CoCrFeO4. Fuel lean samples possess high magnetic saturation. The stoichiometric ratio results in finest nano-particles and structural and magnetic properties are very critically dependent on fuel to nitrate ratio.

Insular cortex metabolite changes in obstructive sleep apnea.

PubMed

Yadav, Santosh K; Kumar, Rajesh; Macey, Paul M; Woo, Mary A; Yan-Go, Frisca L; Harper, Ronald M

2014-05-01

Adults with obstructive sleep apnea (OSA) show significant autonomic and neuropsychologic deficits, which may derive from damage to insular regions that serve those functions. The aim was to assess glial and neuronal status from anterior insular metabolites in OSA versus controls, using proton magnetic resonance spectroscopy (PMRS), and thus to provide insights for neuroprotection against tissue changes, and to reduce injury consequences. Cross-sectional study. University-based medical center. Thirty-six patients with OSA, 53 controls. None. We performed PMRS in bilateral anterior insulae using a 3.0-Tesla magnetic resonance imaging scanner, calculated N-acetylaspartate/creatine (NAA/Cr), choline/creatine (Cho/Cr), myo-inositol/creatine (MI/Cr), and MI/NAA metabolite ratios, and examined daytime sleepiness (Epworth Sleepiness Scale, ESS), sleep quality (Pittsburgh Sleep Quality Index, PSQI), and neuropsychologic status (Beck Depression Inventory II [BDI-II] and Beck Anxiety Inventory [BAI]). Body mass index, BAI, BDI-II, PSQI, and ESS significantly differed between groups. NAA/ Cr ratios were significantly reduced bilaterally, and left-sided MI/Cr and MI/NAA ratios were increased in OSA over controls. Significant positive correlations emerged between left insular MI/Cr ratios and apnea-hypopnea index values, right insular Cho/Cr ratios and BDI-II and BAI scores, and negative correlations appeared between left insular NAA/Cr ratios and PSQI scores and between right-side MI/Cr ratios and baseline and nadir change in O2 saturation. Adults with obstructive sleep apnea showed bilaterally reduced N-acetylaspartate and left-side increased myo-inositol anterior insular metabolites, indicating neuronal damage and increased glial activation, respectively, which may contribute to abnormal autonomic and neuropsychologic functions in the condition. The activated glial status likely indicates increased inflammatory action that may induce more neuronal injury, and suggests separate approaches for glial and neuronal protection.

Effect of chromium picolinate supplementation on growth performance and meat characteristics of swine.

PubMed

Zhang, Hongbing; Dong, Baojun; Zhang, Minhong; Yang, Jiajun

2011-06-01

The purpose of this study was to evaluate the effect of supplemental chromium (Cr) in the form of chromium picolinate (CrPic) on swine growth performance, meat quality, and protein deposition in skeletal muscle. Forty-eight piglets were divided into three groups randomly, fed with three different dietary levels of Cr (common basal feedstuff supplemented with a dose of 1.61 μg/g or 3.22 μg/g CrPic, which corresponded to 0.2 and 0.4 μg/g Cr). Results indicated that during the growing period (1-35 days), pigs fed with the diet supplemented with CrPic showed no improvement in body mass, average daily gain (ADG), feed consumption, or feed conversion rate (FCR) (P > 0.05). During the finishing period, a supplementary dose of 0.2 μg Cr/g improved daily weight gain significantly (P < 0.05), while the situation had no significance with 0.4 μg Cr/g (P > 0.05) supplemented. For the entire growing-finishing period, body mass increased by 3.86%, ADG rose by 6.08%, and the FCR decreased by 3.30%; levels of total muscular pigment and that in the ribeye areas significantly improved (P < 0.05) when supplementation with 0.2 μg Cr/g (P < 0.05) was employed. However, there were no significant changes when supplemented with 0.4 μg Cr/g. While there were no changes in yield of carcass, back fat, water holding capacity, or levels of muscular crude protein and fat (P > 0.05) in treatment, the ratio of fat-lean and RNA/DNA increased significantly supplemented with 0.2 μg Cr/g (P < 0.05), but there were no significance with 0.4 μg Cr/g supplementation. In addition, the muscular levels of cholesterol had slightly decreased and the content of DNA in skeletal muscle showed no marked changes with 0.2 or 0.4 μg/g Cr supplementation. In conclusion, the present results suggested that dietary Cr supplementation in the dose of 0.2 μg/g could promote the growth performance, carcass characteristics, and protein deposition.

Oxygenates vs. synthesis gas

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

Kamil Klier; Richard G. Herman; Alessandra Beretta

1999-04-01

Methanol synthesis from H{sub 2}/CO has been carried out at 7.6 MPa over zirconia-supported copper catalysts. Catalysts with nominal compositions of 10/90 mol% and 30/70 mol% Cu/ZrO{sub 2} were used in this study. Additionally, a 3 mol% cesium-doped 10/90 catalyst was prepared to study the effect of doping with heavy alkali, and this promoter greatly increased the methanol productivity. The effects of CO{sub 2} addition, water injection, reaction temperature, and H{sub 2}/C0 ratio have been investigated. Both CO{sub 2} addition to the synthesis gas and cesium doping of the catalyst promoted methanol synthesis, while inhibiting the synthesis of dimethyl ether.more » Injection of water, however, was found to slightly suppress methanol and dimethyl ether formation while being converted to CO{sub 2} via the water gas shift reaction over these catalysts. There was no clear correlation between copper surface area and catalyst activity. Surface analysis of the tested samples revealed that copper tended to migrate and enrich the catalyst surface. The concept of employing a double-bed reactor with a pronounced temperature gradient to enhance higher alcohol synthesis was explored, and it was found that utilization of a Cs-promoted Cu/ZnO/Cr{sub 2}O{sub 3} catalyst as a first lower temperature bed and a Cs-promoted ZnO/Cr{sub 2}O{sub 3} catalyst as a second high-temperature bed significantly promoted the productivity of 2-methyl-1-propanol (isobutanol) from H{sub 2}/CO synthesis gas mixtures. While the conversion of CO to C{sub 2+} oxygenates over the double-bed configuration was comparable to that observed over the single Cu-based catalyst, major changes in the product distribution occurred by the coupling to the zinc chromite catalyst; that is, the productivity of the C{sub 1}-C{sub 3} alcohols decreased dramatically, and 2-methyl branched alcohols were selectively formed. The desirable methanol/2-methyl oxygenate molar ratios close to 1 were obtained in the present double-bed system that provides the feedstock for the synthesis of high octane and high cetane ethers, where the isobutanol productivity was as high as 139 g/kg cat/hr. Higher alcohol synthesis has been investigated over a Cs/Cu/ZnO/Cr{sub 2}O{sub 3} catalyst at temperatures higher (up to 703K) than those previously utilized, and no sintering of the catalyst was observed during the short-term testing. However, the higher reaction temperatures led to lower CO conversion levels and lower yield of alcohols, especially of methanol, because of equilibrium limitations. With the double catalyst bed configuration, the effect of pressure in the range of 7.6--12.4 MPa on catalyst activity and selectivity was studied. The upper bed was composed of the copper-based catalyst at 598K, and the lower bed consisted of a copper-free Cs-ZnO/Cr{sub 2}O{sub 3} catalyst at a high temperature of 678K. High pressure was found to increase CO conversion to oxygenated products, although the increase in isobutanol productivity did not keep pace with that of methanol. It was also shown that the Cs/Cu/ZnO/Cr{sub 2}O{sub 3} catalyst could be utilized to advantage as the second-bed catalyst at 613--643K instead of the previously used copper-free Cs-ZnO/ Cr{sub 2}O{sub 3} catalyst at higher temperature, With double Cs/Cu/ZnO/Cr{sub 2}O{sub 3} catalysts, high space time yields of up to 202 g/kg cat/hr, with high selectivity to isobutanol, were achieved.« less

Effects of supplemental chromium picolinate and chromium nanoparticles on performance and antibody titers of infectious bronchitis and avian influenza of broiler chickens under heat stress condition.

PubMed

Hajializadeh, Farhad; Ghahri, Hasan; Talebi, Alireza

2017-01-01

This experiment was carried out to investigate the effects of different levels chromium picolinate (CrPic) and chromium nanoparticles (nano-Cr) on the performance and immune function of broilers under heat stress condition. A total of 320 Ross 308 broiler chicks (from 21 to 42 days) were assigned randomly into eight treatment groups (four replicates per treatment, and 10 chicks per replicate) and be reared at either thermoneutral (21 ˚C) or heat stress (36 ◦ C). The treatments were control (T1) group without supplementation and heat stress, T2 as a heat stress group without supplementation, T3, T4 and T5 groups which were supplemented with 500, 1000 and 1500 ppb CrPic in diet with heat stress, respectively and T6, T7 and T8 groups which were supplemented with 500, 1000 and 1500 ppb nano-chromium in diet under heat stress, respectively. Supplementation of chromium and nano-chromium improved performance including weight gain and feed conversion ratio of heat-stressed chickens. Antibody titers against avian influenza (AI) and infectious bronchitis (IB) at 21 to 42 days of age in broilers fed supplemental chromium and nano-chromium were higher than broiler chickens fed control diet ( p < 0.05). Nano-chromium supplementation at level of 1000 ppb and CrPic at level of 1500 ppb improved the antibody titers against AI and IB of broilers under heat stress conditions. It can be concluded from these findings that dietary supplementation of CrPic and nano-Cr can improve performance and antibody titers against AI and IB under heat stress conditions in broilers.

Prediction of contrast-induced nephropathy in diabetic patients undergoing elective cardiac catheterization or PCI: role of volume-to-creatinine clearance ratio and iodine dose-to-creatinine clearance ratio.

PubMed

Worasuwannarak, Surapong; Pornratanarangsi, Suwatchai

2010-01-01

To assess a role of volume-to-creatinine clearance ratio (V/CrCl) and iodine dose-to-creatinine clearance ratio (I-dose/CrCl) in predicting contrast- induced nephropathy (CIN) in diabetic patients undergoing elective cardiac catheterization or percutaneous coronary intervention (PCI). In diabetic patients undergoing cardiac catheterization or PCI, the incidence of CIN is higher than in non-diabetic patients. High doses of contrast media also increase the likelihood of renal dysfunction. The ratio of the volume of contrast media to creatinine clearance (V/CrCl) and iodine dose-to-creatinine clearance (I-dose/CrCl) has been shown to correlate with the area under the curve of contrast media concentration over time and was used to predict the occurrence of CIN in unselected patients. No study has been conducted specifically in diabetic patients undergoing cardiac catheterization or PCI before. We conducted a prospective, single center study. The V/CrCl and I-dose/CrCl were calculated in diabetic patients undergoing elective cardiac catheterization or PCI. An increase in serum creatinine of > 0.5 mg/dl or > 25% by 7 days from baseline was considered CIN. The incidence of CIN was determined. The predictive value of V/CrCl and I-dose/CrCl for CIN were assessed using multivariable logistic regression. The total number of patients that had been enrolled in the study was 248; Male 50.8%. The overall incidence of CIN was 5.2%. The mean age for the entire population was 65 +/- 9 years; the mean body mass index was 25.6 +/- 4.0 kg/m2; and the mean creatinine clearance was 60.6 +/- 27.4 ml/min. The mean values of V/CrCl for patients with and without CIN were 3.7 +/- 2.9 and 2.2 +/- 1.7 (p = 0.041). The mean values of I-dose/CrCl for patients with and without CIN were 1.31 +/- 0.94 and 0.82 +/- 0.63 (p = 0.042). The receiver-operator characteristic curve analysis indicated that a V/CrCl ratio of 2.60 and I-dose/CrCl of 0.98 were fair predictors of CIN. After adjusting for other known predictors of CIN, a V/CrCl ratio > or = 2.60 remained the only significant predictor of CIN (Odds ratio 5.8; 95% confidence interval 1.7-19.4, p = 0.005). A V/CrCl ratio > or = 2.60 was a significant predictor of CIN in diabetic patients undergoing elective cardiac catheterization or PCI.

Natural Cr3+-rich ettringite: occurrence, properties, and crystal structure

NASA Astrophysics Data System (ADS)

Seryotkin, Yurii V.; Sokol, Ella V.; Kokh, Svetlana N.; Murashko, Mikhail N.

2017-08-01

Cr3+-rich ettringite with Cr3+→Al substitution and Cr/(Cr + Al) ratios up to 0.40-0.50 was found in mineral assemblages of the Ma'aleh Adumim area of Mottled Zone (Judean Desert). The Cr3+-rich compositions were the latest in the thaumasite → ettringite-thaumasite solid solution → ettringite → ettringite-bentorite solid solution series. The mineral-forming solution was enriched in Cr3+ and had a pH buffered by afwillite at 11-12. Chromium was inherited from larnite rocks produced by high-temperature combustion metamorphic alteration of bioproductive calcareous sediments. The Cr/(Cr + Al) ratios are within 0.10-0.15 in most of the analysed crystals. This degree of substitution imparts pink colouration to the crystals, but does not affect their habit (a combination of monohedra and a prism). The habit changes to pyramid faces in coarse and later Cr3+-bearing crystals as Cr/(Cr + Al) ratios increase abruptly to 0.40-0.50. Single-crystal XRD analysis of one Cr-free and two Cr3+-rich samples and their structure determination and refinement indicate that the Cr-rich crystals (with Cr/(Cr + Al) to 0.3) preserve the symmetry and metrics of ettringite. The Ca-O bonding network undergoes differentiation with increase of Cr3+ concentration at octahedral M sites. The compression of Ca2 and expansion of Ca1 polyhedra sub-networks correlates with the degree of Cr3+→Al substitution.

Negative-Electrode Catalysts for Fe/Cr Redox Cells

NASA Technical Reports Server (NTRS)

Gahn, R. F.; Hagedorn, N.

1987-01-01

Electrodes perform more consistently and less expensive. Surfaces catalyzed by bismuth and bismuth/lead developed for application on chromium electrode in iron/chromium redox electrochemical energy storage system. NASA Fe/Cr storage system incorporates two soluble electrodes consisting of acidified solutions of iron chloride (FeC13 and FeC12) and chromium chloride (CrC13 and CrC12) oxidized and reduced in power-conversion unit to store and produce electricity. Electrolytes circulated with pumps and stored in external tanks.

> 6 MW peak power at 532 nm from passively Q-switched Nd:YAG/Cr4+:YAG microchip laser.

PubMed

Bhandari, Rakesh; Taira, Takunori

2011-09-26

Megawatt peak power, giant pulse microchip lasers are attractive for wavelength conversion, provided their output is linearly polarized. We use a [110] cut Cr(4+):YAG for passively Q-switched Nd:YAG microchip laser to obtain a stable, linearly polarized output. Further, we optimize the conditions for second harmonic generation at 532 nm wavelength to achieve > 6 MW peak power, 1.7 mJ, 265 ps, 100 Hz pulses with a conversion efficiency of 85%. © 2011 Optical Society of America

Production of Chromium Oxide from Turkish Chromite Concentrate Using Ethanol

NASA Astrophysics Data System (ADS)

Aktas, S.; Eyuboglu, C.; Morcali, M. H.; Özbey, S.; Sucuoglu, Y.

2015-05-01

In this study, the possibility of chromium extraction from Turkish chromite concentrate and the production of chromium oxide were investigated. For the conversion of chromium(III) into chromium(VI), NaOH was employed, as well as air with a rate of 20 L/min. The effects of the base amount, fusing temperature, and fusing time on the chromium conversion percentage were investigated in detail. The conversion kinetics of chromium(III) to chromium(VI) was also undertaken. Following the steps of dissolving the sodium chromate in water and filtering, aluminum hydroxide was precipitated by adjusting the pH level of the solution. The chromium(VI) solution was subsequently converted to Cr(III) by the combination of sulfuric acid and ethanol. Interestingly, it was observed that ethanol precipitated chromium as chromium(VI) at mildly acidic pH levels, although this effect is more pronounced for K2Cr2O7 than Na2Cr2O7. On the other hand, in the strongly acidic regime, ethanol acted as a reducing agent role in that chromium(VI) was converted into Cr(III) whereas ethanol itself was oxidized to carbon dioxide and water. Subsequently, chromium hydroxide was obtained by the help of sodium hydroxide and converted to chromium oxide by heating at 800 °C, as indicated in thermo gravimetric analysis (TGA).

The Relationship of Thioredoxin-1 and Cisplatin Resistance: Its Impact on ROS and Oxidative Metabolism in Lung Cancer Cells

PubMed Central

Wangpaichitr, Medhi; Theodoropoulos, George; Wu, Chunjing; You, Min; Feun, Lynn G.; Kuo, Macus T.; Savaraj, Niramol

2012-01-01

Elimination of cisplatin resistant (CR) lung cancer cells remains a major obstacle. We have shown that CR tumors have higher reactive oxygen species (ROS) levels and can be exploited for targeted therapy. Here we show that increased secretion of the antioxidant thioredoxin-1 (TRX1) resulted in lowered intracellular TRX1, and contributed to higher ROS in CR tumors in vivo and in vitro. By reconstitutingTRX1 protein in CR cells, we increased sensitivity to cisplatin but decreased sensitivity to elesclomol (ROS inducer). Conversely, decreased TRX1 protein in parental cells reduced the sensitivity to cisplatin but increased sensitivity to elesclomol. CR cells had increased endogenous oxygen consumption and mitochondrial activity but decreased lactic acid production. They also exhibited higher levels of argininosuccinate synthetase (ASS) and fumarase (FH) mRNA which contributed to oxidative metabolism (OXMET) when compared to parental cells. Restoring intracellular TRX1 protein in CR cells resulted in lowering ASS and FH mRNAs which in turn sensitized them to arginine deprivation. Interestingly, CR cells also possessed significantly higher basal levels of acetyl-CoA-carboxylase (ACC) and fatty acid synthase (FAS). Over-expressing TRX1 lowered ACC and FAS proteins expressions in CR cells. Chemical inhibition and siRNA of ACC resulted in significant cell death in CR compared to parental cells. Conversely, TRX1 over-expressed CR cells resisted to TOFA-induced death. Collectively, lowering TRX1 expression through increased secretion leads CR cells to higher ROS production and increase in dependency on OXMET. These changes raise an intriguing therapeutic potential for future therapy in cisplatin resistant lung cancer. PMID:22248473

The MSFR as a flexible CR reactor: the viewpoint of safety

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

Fiorina, C.; Cammi, A.; Franceschini, F.

2013-07-01

In this paper, the possibility has first been discussed of using the liquid-fuelled Molten Salt Fast Reactor (MSFR) as a flexible conversion ratio (CR) reactor without design modification. By tuning the reprocessing rate it is possible to determine the content of fission products in the core, which in turn can significantly affect the neutron economy without incurring in solubility problems. The MSFR can thus be operated as U-233 breeder (CR>1), iso-breeder (CR=1) and burner reactor (CR<1). In particular a 40 year doubling time can be achieved, as well as a considerable Transuranics and MA (minor actinide) burning rate equal tomore » about 150 kg{sub HN}/GWE-yr. The safety parameters of the MSFR have then been evaluated for different fuel cycle strategies. Th use and a softer spectrum combine to give a strong Doppler coefficient, one order of magnitude higher compared to traditional fast reactors (FRs). The fuel expansion coefficient is comparable to the Doppler coefficient and is only mildly affected by core compositions, thus assisting the fuel cycle flexibility of the MSFR. βeff and generation time are comparable to the case of traditional FRs, if a static fuel is assumed. A notable reduction of βeff is caused by salt circulation, but a low value of this parameter is a limited concern in the MSFR thanks to the lack of a burnup reactivity swing and of positive feedbacks. A simple approach has also been developed to evaluate the MSFR capabilities to withstand all typical double-fault accidents, for different fuel cycle options.« less

Evaluation of the Children's Eating Habits Questionnaire used in the IDEFICS study by relating urinary calcium and potassium to milk consumption frequencies among European children.

PubMed

Huybrechts, I; Börnhorst, C; Pala, V; Moreno, L A; Barba, G; Lissner, L; Fraterman, A; Veidebaum, T; Hebestreit, A; Sieri, S; Ottevaere, C; Tornaritis, M; Molnár, D; Ahrens, W; De Henauw, S

2011-04-01

Measuring dietary intake in children is notoriously difficult. Therefore, it is crucial to evaluate the performance of dietary intake assessment methods in children. Given the important contribution of milk consumption to calcium (Ca) and potassium (K) intakes, urinary calcium (UCa) and potassium (UK) excretions in spot urine samples could be used for estimating correlations with milk consumption frequencies. The aim of this study was to evaluate the assessment of milk consumption frequencies derived from the Food Frequency Questionnaire section of the Children's Eating Habits Questionnaire (CEHQ-FFQ) used in the IDEFICS (Identification and prevention of dietary- and lifestyle induced health effects in children and infants) study by comparing with UCa and UK excretions in spot urine samples. This study was conducted as a setting-based community-oriented intervention study and results from the first cross-sectional survey have been included in the analysis. A total of 10,309 children aged 2-10 years from eight European countries are included in this analysis. UCa and UK excretions were measured in morning spot urine samples. Calcium and potassium urine concentrations were standardised for urinary creatinine (Cr) excretion. Ratios of UCa/Cr and UK/Cr were used for multivariate regression analyses after logarithmic transformation to obtain normal distributions of data. Milk consumption frequencies were obtained from the CEHQ-FFQ. Multivariate regression analyses were used to investigate the effect of milk consumption frequencies on UCa and UK concentrations, adjusting for age, gender, study centre, soft drink consumption and frequency of main meals consumed at home. A significant positive correlation was found between milk consumption frequencies and ratios of UK/Cr and a weaker but still significant positive correlation with ratios of UCa/Cr, when using crude or partial Spearman's correlations. Multivariate regression analyses showed that milk consumption frequencies were predictive of UCa/Cr and UK/Cr ratios, when adjusted for age, gender, study centre, soft drink consumption and frequency of main meals consumed at home. Mean ratios of UK/Cr for increasing milk consumption frequency tertiles showed a progressive increase in UK/Cr. Children consuming at least two milk servings per day had significantly higher mean UCa/Cr and UK/Cr ratios than children who did not. Large differences in correlations between milk consumption frequencies and ratios of UCa/Cr and UK/Cr were found between the different study centres. Higher milk consumption frequencies resulted in a progressive increase in UK/Cr and UCa/Cr ratios, reflecting the higher Ca and K intakes that coincide with increasing milk consumption, which constitutes a major K and Ca source in children's diet.

Estimation of Daily Proteinuria in Patients with Amyloidosis by Using the Protein-To-Creatinine ratio in Random Urine Samples

PubMed Central

Talamo, Giampaolo; Mir Muhammad, A.; Pandey, Manoj K.; Zhu, Junjia; Creer, Michael H.; Malysz, Jozef

2015-01-01

Measurement of daily proteinuria in patients with amyloidosis is recommended at the time of diagnosis for assessing renal involvement, and for monitoring disease activity. Renal involvement is usually defined by proteinuria >500 mg/day. We evaluated the accuracy of the random urine protein-to-creatinine ratio (Pr/Cr) in predicting 24 hour proteinuria in patient with amyloidosis. We compared results of random urine Pr/Cr ratio and concomitant 24-hour urine collections in 44 patients with amyloidosis. We found a strong correlation (Spearman’s ρ=0.874) between the Pr/Cr ratio and the 24 hour urine protein excretion. For predicting renal involvement, the optimal cut-off point of the Pr/Cr ratio was 715 mg/g. The sensitivity and specificity for this point were 91.8% and 95.5%, respectively, and the area under the curve value was 97.4%. We conclude that the random urine Pr/Cr ratio could be useful in the screening of renal involvement in patients with amyloidosis. If validated in a prospective study, the random urine Pr/Cr ratio could replace the 24 hour urine collection for the assessment of daily proteinuria and presence of nephrotic syndrome in patients with amyloidosis. PMID:25918613

Hydrogen adsorption on two catalysts for the ortho- to parahydrogen conversion: Cr-doped silica and ferric oxide gel.

PubMed

Hartl, Monika; Gillis, Robert Chad; Daemen, Luke; Olds, Daniel P; Page, Katherine; Carlson, Stefan; Cheng, Yongqiang; Hügle, Thomas; Iverson, Erik B; Ramirez-Cuesta, A J; Lee, Yongjoong; Muhrer, Günter

2016-06-29

Molecular hydrogen exists in two spin-rotation coupled states: parahydrogen and orthohydrogen. Due to the variation of energy with rotational level, the occupation of ortho- and parahydrogen states is temperature dependent, with parahydrogen being the dominant species at low temperatures. The equilibrium at 20 K (99.8% parahydrogen) can be reached by natural conversion only after a lengthy process. With the use of a suitable catalyst, this process can be shortened significantly. Two types of commercial catalysts currently being used for ortho- to parahydrogen conversion are: iron(iii) oxide (Fe2O3, IONEX®), and chromium(ii) oxide doped silica catalyst (CrO·SiO2, OXISORB®). We investigate the interaction of ortho- and parahydrogen with the surfaces of these ortho-para conversion catalysts using neutron vibrational spectroscopy. The catalytic surfaces have been characterized using X-ray absorption fine structure (XAFS) and X-ray/neutron pair distribution function measurements.

Evaluation of Serum, Urine, and Hair Chromium Levels as Indices of Chromium Exposure and the Relationship of these Indices to Serum Lipid and Insulin Levels.

NASA Astrophysics Data System (ADS)

Randall, Janis Avril

Concentrations of chromium (Cr) in hair, serum, and urine, and serum concentrations of insulin and lipids of a selected group of men exposed to trivalent Cr (Cr III) were compared with those of men not exposed to Cr. Seventy -three tannery workers (TW) (mean age 37 +/- 12 years) from four Southern Ontario tanneries and fifty-two control subjects (CS) (mean age 41 +/- 13 years), matched for age, race, and socioeconomic status, from the Guelph and Toronto areas participated. The median hair and serum Cr concentrations for the TW were significantly higher (p < 0.01) than for the CS (hair Cr 453 vs 124 ng/g; serum Cr 0.49 vs 0.15 ng/ml). Median urinary Cr/creatinine ratios (Cr/Cre) for the TW on Monday morning (0.83 ng/mg) and Friday afternoon (0.68 ng/mg) were also significantly higher (p < 0.01, p < 0.01, respectively) than the median urinary Cr/Cre ratio for the urine samples collected on a Friday afternoon from the CS (0.18 ng/mg). For the TW, the median Friday urinary Cr/Cre ratio was significantly higher (p = 0.03) than the corresponding Monday Cr/Cre ratio. For the TW, urinary Cr/Cre ratios (Monday and Friday) were correlated significantly and positively with both Cr concentrations in serum (r = 0.45, p < 0.01; r = 0.71, p < 0.01, respectively) and in hair (r = 0.43, p < 0.01; r = 0.64, p < 0.01, respectively). Concentrations of Cr in hair and in serum were also significantly correlated (r = 0.52, p < 0.01). There were no significant differences between the TW and CS in serum concentrations of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), or triglycerides, or in calculated values for low-density lipoprotein cholesterol, %HDL-C, and TC/HDL-C. Likewise, no significant differences in serum insulin concentrations were noted between the two groups. Results of this study indicate that Cr III, from compounds used in the leather tanning industry, is absorbed and retained. Absorption of Cr III had no significant effect on serum insulin concentrations or serum lipid profiles. These results also suggest that concentrations of Cr in hair, serum, and urine are valid biological indices of industrial exposure to Cr III.

Homogeneous and Heterogeneous (Fex, Cr1-x)(OH)3 Precipitation: Implications for Cr Sequestration

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

Dai, Chong; Zuo, Xiaobing; Cao, B

2016-02-16

The formation of (Fe, Cr)(OH)3 nanoparticles determines the fate of aqueous Cr in many aquatic environments. Using small angle X-ray scattering, precipitation rates of (Fe, Cr)(OH)3 nanoparticles in solution and on quartz were quantified from 0.1 mM Fe(III) solutions containing 0 – 0.25 mM Cr(III) at pH = 3.7 ± 0.2. Concentration ratio of aqueous Cr(III)/Fe(III) controlled the chemical composition (x) of (Fex, Cr1-x)(OH)3 precipitates, solutions’ supersaturation with respect to precipitates, and the surface charge of quartz. Therefore, aqueous Cr(III)/Fe(III) ratio affected homogeneous (in solution) and heterogeneous (on quartz) precipitation rates of (Fex, Cr1-x)(OH)3 through different mechanisms. The sequestration mechanismsmore » of Cr(III) in precipitates were also investigated. In solutions with high aqueous Cr(III)/Fe(III) ratios, surface enrichment of Cr(III) on the precipitates occurred, resulting in slower particle growth in solution. From solutions with 0 – 0.1 mM Cr(III), the particles on quartz grew from 2 to 4 nm within 1 h. Interestingly, from solution with 0.25 mM Cr(III), particles of two distinct sizes (2 and 6 nm) formed on quartz, and their sizes remained unchanged throughout the reaction. Our study provided new insights on homogeneous and heterogeneous precipitation of (Fex, Cr1-x)(OH)3 nanoparticles, which can help determine the fate of Cr in aquatic environments.« less

Formation and function of chromate conversion coating on aircraft aluminum alloy probed by vibrational spectroscopy

NASA Astrophysics Data System (ADS)

Xia, Lin

2000-10-01

A Chromate Conversion Coating (CCC) is currently one of the most effective methods for protecting aluminum alloys from corrosion. Its unique "self-healing" property has been proved to be critical in corrosion prevention. During the formation process, CrVI, is "stored" in the CCC films. Under in-field conditions, most of the CrVI can leach out and diffuse to local defects, and stop corrosion. However, the involvement of highly toxic CrVI makes CCC system environmentally hazardous. In order to find less-toxic alternatives, the formation and protection mechanisms of CCC must be understood. Formation and function of CCC film are the focus of this study, and vibrational spectroscopy was chosen due to its superior structural sensitivity. First, the structure of CCC film was characterized. The structural similarity between CCC film and a synthetic Cr-mixed-oxide was found, and certain tests were conducted on the bulk synthetic powder which were not feasible on the thin film. All of the structural studies indicated that CCC film is mainly a CrIII-hydroxide gel layer, which adsorbs CrVI-oxy species through CrIII-O-Cr VI chemical bonds. Further analysis revealed the reversible Cr III-CrVI adsorption-desorption equilibrium, and a mathematical model ("Langmuir" model) was established to explain the Cr VI storage-release mechanism quantitatively. In addition, the function of Fe(CN)63-, an additive in the coating solution, was studied. The results indicate that Fe(CN)63- mediates the slow reaction between Al and CrVI, and the mediation mechanism can be illustrated as below: FeCN 3- 6+Al=FeCN 4-6+Al3+ ↑ FeCN 4- 6+CrVI=FeCN 3-6+CrIII In general, the formation of CCC is mediated by Fe(CN)63-, thus Al reduces CrVI quickly and generates CrIII-hydroxide on the alloy surface. The nascent CrIII-hydroxide is chemically active enough to form chemical bonds with CrVI from the solution, through Cr III-O-CrVI bonding. Such CrIII-O-Cr VI structure can form and break up reversibly according to the Langmuir model, providing mobile CrVI for in-field protection.

Calorie restriction hysteretically primes aging Saccharomyces cerevisiae toward more effective oxidative metabolism.

PubMed

Tahara, Erich B; Cunha, Fernanda M; Basso, Thiago O; Della Bianca, Bianca E; Gombert, Andreas K; Kowaltowski, Alicia J

2013-01-01

Calorie restriction (CR) is an intervention known to extend the lifespan of a wide variety of organisms. In S. cerevisiae, chronological lifespan is prolonged by decreasing glucose availability in the culture media, a model for CR. The mechanism has been proposed to involve an increase in the oxidative (versus fermentative) metabolism of glucose. Here, we measured wild-type and respiratory incompetent (ρ(0)) S. cerevisiae biomass formation, pH, oxygen and glucose consumption, and the evolution of ethanol, glycerol, acetate, pyruvate and succinate levels during the course of 28 days of chronological aging, aiming to identify metabolic changes responsible for the effects of CR. The concomitant and quantitative measurements allowed for calculations of conversion factors between different pairs of substrates and products, maximum specific substrate consumption and product formation rates and maximum specific growth rates. Interestingly, we found that the limitation of glucose availability in CR S. cerevisiae cultures hysteretically increases oxygen consumption rates many hours after the complete exhaustion of glucose from the media. Surprisingly, glucose-to-ethanol conversion and cellular growth supported by glucose were not quantitatively altered by CR. Instead, we found that CR primed the cells for earlier, faster and more efficient metabolism of respiratory substrates, especially ethanol. Since lifespan-enhancing effects of CR are absent in respiratory incompetent ρ(0) cells, we propose that the hysteretic effect of glucose limitation on oxidative metabolism is central toward chronological lifespan extension by CR in this yeast.

Day-to-day variation of urinary NGAL and rational for creatinine correction.

PubMed

Helmersson-Karlqvist, Johanna; Arnlöv, Johan; Larsson, Anders

2013-01-01

The number of clinical studies evaluating the new tubular biomarker urinary neutrophil gelatinase-associated lipocalin (U-NGAL) in urine are increasing. There is no consensus whether absolute U-NGAL concentrations or urinary NGAL/creatinine (U-NGAL/Cr) ratios should be used when chronic tubular dysfunction is studied. The aim was to study the biological variation of U-NGAL in healthy subjects and the rational for urinary creatinine (U-Cr) correction in two different study samples. To study biological variation of U-NGAL and U-NGAL/Cr ratio and the association between U-NGAL and U-Cr in healthy subjects 13 young males and females (median age 29 years) collected morning urine in 10 consecutive days. Additionally, a random subsample of 400 males from a population-based cohort (aged 78 years) collecting 24-hour urine during 1 day was studied. The calculated biological variation for absolute U-NGAL was 27% and for U-NGAL/Cr ratio, 101%. Absolute U-NGAL increased linearly with U-Cr concentration (the theoretical basis for creatinine adjustment) in the older males (R=0.19, P<0.001) and with borderline significance in the young adults (R=0.16, P=0.08). The U-NGAL/Cr ratio was, however, negatively associated with creatinine in the older males (R=-0.14, P<0.01) and in the young adults (R=-0.16, P=0.07) indicating a slight "overadjustment." The study provides some support for the use of U-NGAL/Cr ratio but the rather large biological variation and risk of possible overadjustment need to be considered. Both absolute U-NGAL and U-NGAL/Cr ratios should be reported for the estimation of chronic tubular dysfunction. Copyright © 2012 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Comparison of LCModel and SAGE in Analysis of Brain Metabolite Concentrations-A study of Patients with Mild Cognitive Impairment.

PubMed

Shih, Chiu-Ming; Lai, Jui-Jen; Chang, Chin-Ching; Chen, Cheng-Sheng; Yeh, Yi-Chun; Jaw, Twei-Shiun; Hsu, Jui-Sheng; Li, Chun-Wei

2017-03-15

The purpose of this study was to compare brain metabolite concentration ratios determined by LCModel and Spectroscopy Analysis by General Electric (SAGE) quantitative methods to elucidate the advantages and disadvantages of each method. A total of 10 healthy volunteers and 10 patients with mild cognitive impairment (MCI) were recruited in this study. A point-resolved spectroscopy (PRESS) sequence was used to obtain the brain magnetic resonance spectroscopy (MRS) spectra of the volunteers and patients, as well as the General Electric (GE) MRS-HD-sphere phantom. The brain metabolite concentration ratios were estimated based on the peak area obtained from both LCModel and SAGE software. Three brain regions were sampled for each volunteer or patient, and 20 replicates were acquired at different times for the phantom analysis. The metabolite ratios of the GE phantom were estimated to be myo-inositol (mI)/creatine (Cr): 0.70 ± 0.01, choline (Cho)/Cr: 0.37 ± 0.00, N-acetylaspartate (NAA)/Cr: 1.26 ± 0.02, and NAA/mI: 1.81 ± 0.04 by LCModel, and mI/Cr: 0.88 ± 0.15, Cho/Cr: 0.35 ± 0.01, NAA/Cr: 1.33 ± 0.03, and NAA/mI: 1.55 ± 0.26 by SAGE. In the healthy volunteers and MCI patients, the ratios of mI/Cr and Cho/Cr estimated by LCModel were higher than those estimated by SAGE. In contrast, the ratio of NAA/Cr estimated by LCModel was lower than that estimated by SAGE. Both methods were acceptable in estimating brain metabolite concentration ratios. However, LCModel was marginally more accurate than SAGE because of its full automation, basis set, and user independency.

Cryogenic Etching of High Aspect Ratio 400 nm Pitch Silicon Gratings.

PubMed

Miao, Houxun; Chen, Lei; Mirzaeimoghri, Mona; Kasica, Richard; Wen, Han

2016-10-01

The cryogenic process and Bosch process are two widely used processes for reactive ion etching of high aspect ratio silicon structures. This paper focuses on the cryogenic deep etching of 400 nm pitch silicon gratings with various etching mask materials including polymer, Cr, SiO 2 and Cr-on-polymer. The undercut is found to be the key factor limiting the achievable aspect ratio for the direct hard masks of Cr and SiO 2 , while the etch selectivity responds to the limitation of the polymer mask. The Cr-on-polymer mask provides the same high selectivity as Cr and reduces the excessive undercut introduced by direct hard masks. By optimizing the etching parameters, we etched a 400 nm pitch grating to ≈ 10.6 μ m depth, corresponding to an aspect ratio of ≈ 53.

Effect of metal ratio and calcination temperature of chromium based mixed oxides catalyst on FAME density from palm fatty acid distillate

NASA Astrophysics Data System (ADS)

Wan, Z.; Fatimah, S.; Shahar, S.; Noor, A. C.

2017-09-01

Mixed oxides chromium based catalysts were synthesized via sol-gel method for the esterification of palm fatty acid distillate (PFAD) to produce fatty acid methyl ester (FAME). The reactions were conducted in a batch reactor at reaction temperature of 160 °C for 4 h and methanol to PFAD molar ratio of 3:1. The effects of catalyst preparation conditions which are the mixed metal ratio and calcination temperature were studied. The various metal ratio of Cr:Mn (1:0, 0:1, 1:1, 1:2 and 2:1) and Cr:Ti (0:1, 1:1, 1:2 and 2:1) resulted in FAME density ranges from 1.041 g/cm3 to 0.853 g/cm3 and 1.107 g/cm3 to 0.836 g/cm3, respectively. The best condition catalyst was found to be Cr:Ti metal ratio of 1:2 and Cr:Mn metal ratio of 1:1. The calcination temperature of the mixed oxides between 300 °C to 700°C shows effect on the FAME density obtained in the reaction. The calcination at 500°C gave the lowest FAME density of 0.836 g/cm3 and 0.853 g/cm3 for Cr:Ti and Cr:Mn mixed oxides, respectively. The density of FAME is within the value range of the biodiesel fuel property. Thus, mixed oxides of Cr-Ti and Cr-Mn have good potentials as heterogeneous catalyst for FAME synthesis from high acid value oils such as PFAD.

A Critical Proton MR Spectroscopy Marker of Alzheimer's Disease Early Neurodegenerative Change: Low Hippocampal NAA/Cr Ratio Impacts APOE ɛ4 Mexico City Children and Their Parents.

PubMed

Calderón-Garcidueñas, Lilian; Mora-Tiscareño, Antonieta; Melo-Sánchez, Gastón; Rodríguez-Díaz, Joel; Torres-Jardón, Ricardo; Styner, Martin; Mukherjee, Partha S; Lin, Weili; Jewells, Valerie

2015-01-01

Severe air pollution exposures produce systemic, respiratory, myocardial, and brain inflammation and Alzheimer's disease (AD) hallmarks in clinically healthy children. We tested whether hippocampal metabolite ratios are associated with contrasting levels of air pollution, APOE, and body mass index (BMI) in paired healthy children and one parent sharing the same APOE alleles. We used 1H-MRS to interrogate bilateral hippocampal single-voxel in 57 children (12.45 ± 3.4 years) and their 48 parents (37.5 ± 6.78 years) from a low pollution city versus Mexico City (MC). NAA/Cr, Cho/Cr, and mI/Cr metabolite ratios were analyzed. The right hippocampus NAA/Cr ratio was significantly different between cohorts (p = 0.007). The NAA/Cr ratio in right hippocampus in controls versus APOE ɛ4 MC children and in left hippocampus in MC APOE ɛ4 parents versus their children was significantly different after adjusting for age, gender, and BMI (p = 0.027 and 0.01, respectively). The NAA/Cr ratio is considered reflective of neuronal density/functional integrity/loss of synapses/higher pTau burden, thus a significant decrease in hippocampal NAA/Cr ratios may constitute a spectral marker of early neurodegeneration in young urbanites. Decreases in NAA/Cr correlate well with cognitive function, behavioral symptoms, and dementia severity; thus, since the progression of AD starts decades before clinical diagnosis, our findings support the hypothesis that under chronic exposures to fine particulate matter and ozone above the standards, neurodegenerative processes start in childhood and APOE ɛ4 carriers are at higher risk. Gene and environmental factors are critical in the development of AD and the identification and neuroprotection of young urbanites at high risk must become a public health priority.

Insular Cortex Metabolite Changes in Obstructive Sleep Apnea

PubMed Central

Yadav, Santosh K.; Kumar, Rajesh; Macey, Paul M.; Woo, Mary A.; Yan-Go, Frisca L.; Harper, Ronald M.

2014-01-01

Study Objective: Adults with obstructive sleep apnea (OSA) show significant autonomic and neuropsychologic deficits, which may derive from damage to insular regions that serve those functions. The aim was to assess glial and neuronal status from anterior insular metabolites in OSA versus controls, using proton magnetic resonance spectroscopy (PMRS), and thus to provide insights for neuroprotection against tissue changes, and to reduce injury consequences. Design: Cross-sectional study. Setting: University-based medical center. Participants: Thirty-six patients with OSA, 53 controls. Interventions: None. Measurements and Results: We performed PMRS in bilateral anterior insulae using a 3.0-Tesla magnetic resonance imaging scanner, calculated N-acetylaspartate/creatine (NAA/Cr), choline/creatine (Cho/Cr), myo-inositol/creatine (MI/Cr), and MI/NAA metabolite ratios, and examined daytime sleepiness (Epworth Sleepiness Scale, ESS), sleep quality (Pittsburgh Sleep Quality Index, PSQI), and neuropsychologic status (Beck Depression Inventory II [BDI-II] and Beck Anxiety Inventory [BAI]). Body mass index, BAI, BDI-II, PSQI, and ESS significantly differed between groups. NAA/ Cr ratios were significantly reduced bilaterally, and left-sided MI/Cr and MI/NAA ratios were increased in OSA over controls. Significant positive correlations emerged between left insular MI/Cr ratios and apnea-hypopnea index values, right insular Cho/Cr ratios and BDI-II and BAI scores, and negative correlations appeared between left insular NAA/Cr ratios and PSQI scores and between right-side MI/Cr ratios and baseline and nadir change in O2 saturation. Conclusions: Adults with obstructive sleep apnea showed bilaterally reduced N-acetylaspartate and left-side increased myo-inositol anterior insular metabolites, indicating neuronal damage and increased glial activation, respectively, which may contribute to abnormal autonomic and neuropsychologic functions in the condition. The activated glial status likely indicates increased inflammatory action that may induce more neuronal injury, and suggests separate approaches for glial and neuronal protection. Citation: Yadav SK, Kumar R, Macey PM, Woo MA, Yan-Go FL, Harper RM. Insular cortex metabolite changes in obstructive sleep apnea. SLEEP 2014;37(5):951-958. PMID:24790274

Proteomic Responses of BEAS-2B Cells to Nontoxic and Toxic Chromium: Protein Indicators of Cytotoxicity Conversion

EPA Science Inventory

Hexavalent chromium (Cr (VI)) is an environmental human carcinogen which primarily targets lungs. Among a variety of toxic mechanisms, disruption of biological pathways via translational and post-translational modifications represents a key mechanism through which Cr (VI) induces...

Similarities of biochemical abnormalities between major depressive disorder and bipolar depression: a proton magnetic resonance spectroscopy study.

PubMed

Zhong, Shuming; Wang, Ying; Zhao, Guoxiang; Xiang, Qi; Ling, Xueying; Liu, Sirun; Huang, Li; Jia, Yanbin

2014-10-01

Depression in the context of bipolar disorder (BD) is often misdiagnosed as major depressive disorder (MDD), leading to mistreatments and poor clinical outcomes for many bipolar patients. Previous neuroimaging studies found mixed results on brain structure, and biochemical metabolism of the two disorders. To eliminate the compounding effects of medication, and aging, this study sought to investigate the brain biochemical changes of treatment-naïve, non-late-life patients with MDD and BD in white matter in prefrontal (WMP) lobe, anterior cingulate cortex (ACC) and hippocampus by using proton magnetic resonance spectroscopy ((1)H-MRS). Three groups of participants were recruited: 26 MDD patients, 20 depressed BD patients, and 13 healthy controls. The multi-voxel (1)H-MRS [repetition time (TR)=1000ms; echo-time (TE)=144ms] was used for the measurement of N-acetylaspartate(NAA), choline containg compounds (Cho), and creatine (Cr) in three brain locations: white matter in prefrontal (WMP) lobe, anterior cingulate cortex (ACC), and hippocampus. Two ratios of NAA/Cr and Cho/Cr as a measure of brain biochemical changes were compared among three experimental groups. On the comparison of brain biochemical changes, both MDD patients and BD patients showed many similarities compared to the controls. They both had a significantly lower NAA/Cr ratio in the left WMP lobe. There were no significant differences among three experimental groups for Cho/Cr ratio in the WMP lobe, and for the ratios of NAA/Cr and Cho/Cr in the bilateral ACC and hippocampus. The only difference between MDD and BD patients existed for the NAA/Cr ratio in the right WMP lobe. While MDD patients had a significantly lower NAA/Cr ratio than controls, BD patients showed no such differences. On the comparison of correlation of medical variables and brain biochemical changes, all participants demonstrated no significant correlations. Reduced NAA/Cr ratio at the left WMP lobe indicated the dysfunction of neuronal viability in deep white matter, in both MDD and BD patients who shared similarities of brain biochemical abnormalities, which might imply an overlap in neuropathology of depression. Copyright © 2014 Elsevier B.V. All rights reserved.

Syntheses of near-net-shaped monolithic hydroxyapatite and hydroxyapatite-ASTM F75 composites by the oxidation of solid metal-bearing precursors

NASA Astrophysics Data System (ADS)

Saw, Eaden

A novel powder-metallurgical route was used to fabricate near net-shaped hydroxyapatite, Ca10(PO4)6(OH)2 (HA) and HA+Co-C-Mo composite bodies. Ca and beta-Ca2P 2O7 with Ca/P ˜ 1.67 was intimately mixed by high-energy mechanical alloying, formed into desired shapes by pressing and machining, and then converted into HA with a series of heat treatments: a 600°C annealing in dry O2 completely oxidized calcium within 3 h, and a subsequent annealing at ≤1150°C in moist O2 yielded phase-pure HA. The reduction in solid volume associated with the oxidation of calcium (Vm[CaO] < Vm[Ca]) was offset by the increase in solid volume associated with the conversion of CaO and Ca2P2O7 into HA. Thus, the overall dimensional changes upon transformation of Ca+beta-Ca2P 2O7 precursors into HA can be relatively small. A mixture of Co-Cr-Mo powder with the precursor prepared from Ca and beta-Ca 2P2O7, targeted to yield a 75 to 25 volume ratio of Co-Cr-Mo to stoichiometric HA were prepared with the same method but different annealing cycles: annealing at 1150°C in de-oxygenized, flowing Ar resulted in partial densification of the composite bodies, and subsequent annealing at 850°C in a moist O2 atmosphere yielded a composite of Co-Cr-Mo alloy with phase-pure HA. The overall dimensional changes upon transformation of Ca+beta-Ca2P2O7+CO-Cr-Mo precursors into HA/Co-Cr-Mo composite were relatively small. In this thesis, the phase and microstructural evolution at various stages of transformation to monolithic HA and to HA/Co-Cr-Mo alloy composites are discussed. Planar reaction couples and powder compacts of CaO-TCP were prepared to study the kinetics for HA formation from CaO+TCP. Pt strips were used in the planar reaction couples as inert markers. These reaction couples were heated at 1150°C for various times in moist O2. The results of powder compact analyses fits Carter's model, which indicated that the rate of HA conversion from CaO and TCP is limited by solid state diffusion of Ca 2+ and/or OH- through the HA layer.

Cardiac rehabilitation attendance and outcomes in coronary artery disease patients.

PubMed

Martin, Billie-Jean; Hauer, Trina; Arena, Ross; Austford, Leslie D; Galbraith, P Diane; Lewin, Adriane M; Knudtson, Merril L; Ghali, William A; Stone, James A; Aggarwal, Sandeep G

2012-08-07

Cardiac rehabilitation (CR) is an efficacious yet underused treatment for patients with coronary artery disease. The objective of this study was to determine the association between CR completion and mortality and resource use. We conducted a prospective cohort study of 5886 subjects (20.8% female; mean age, 60.6 years) who had undergone angiography and were referred for CR in Calgary, AB, Canada, between 1996 and 2009. Outcomes of interest included freedom from emergency room visits, hospitalization, and survival in CR completers versus noncompleters, adjusted for clinical covariates, treatment strategy, and coronary anatomy. Hazard ratios for events for CR completers versus noncompleters were also constructed. A propensity model was used to match completers to noncompleters on baseline characteristics, and each outcome was compared between propensity-matched groups. Of the subjects referred for CR, 2900 (49.3%) completed the program, and an additional 554 subjects started but did not complete CR. CR completion was associated with a lower risk of death, with an adjusted hazard ratio of 0.59 (95% confidence interval, 0.49-0.70). CR completion was also associated with a decreased risk of all-cause hospitalization (adjusted hazard ratio, 0.77; 95% confidence interval, 0.71-0.84) and cardiac hospitalization (adjusted hazard ratio, 0.68; 95% confidence interval, 0.55-0.83) but not with emergency room visits. Propensity-matched analysis demonstrated a persistent association between CR completion and reduced mortality. Among those coronary artery disease patients referred, CR completion is associated with improved survival and decreased hospitalization. There is a need to explore reasons for nonattendance and to test interventions to improve attendance after referral.

White matter NAA/Cho and Cho/Cr ratios at MR spectroscopy are predictive of motor outcome in preterm infants.

PubMed

Kendall, Giles S; Melbourne, Andrew; Johnson, Samantha; Price, David; Bainbridge, Alan; Gunny, Roxanna; Huertas-Ceballos, Angela; Cady, Ernest B; Ourselin, Sebastian; Marlow, Neil; Robertson, Nicola J

2014-04-01

To determine (a) whether diffuse white matter injury of prematurity is associated with an increased choline (Cho)-to-creatine (Cr) ratio and a reduced N-acetylaspartate (NAA)-to-Cho ratio and whether these measures can be used as biomarkers of outcome and (b) if changes in peak area metabolite ratios at magnetic resonance (MR) spectroscopy are associated with changes in T2 and fractional anisotropy (FA) at MR imaging. The local ethics committee approved this study, and informed parental consent was obtained for each infant. At term-equivalent age, 43 infants born at less than 32 weeks gestation underwent conventional and quantitative diffusion-tensor and T2-weighted MR imaging. Single-voxel point-resolved proton (hydrogen 1) MR spectroscopy was performed from a 2-cm(3) voxel centered in the posterior periventricular white matter. Outcome was evaluated by using Bayley scales at a corrected age of 1 year. Associations were investigated with Pearson product moment or Spearman rank order correlation. Differences in ratios in infants with and infants without impairment were tested by using t tests. NAA/Cho and Cho/Cr ratios correlated with the scaled gross motor score and the composite motor score, independent of gestational age (P < .05). FA at diffusion-tensor MR imaging and T2 at MR imaging correlated with the NAA/Cho ratio (P < .05 for both) but not with the Cho/Cr ratio. Infants with motor scores of less than 85 (impaired) had an increased Cho/Cr ratio (P < .03) and a reduced NAA/Cho ratio (P < .01) compared to those without impairment. A combination of increased Cho/Cr ratio and decreased NAA/Cho ratio predicted impaired motor outcome at a corrected age of 1 year with a sensitivity of 0.80 (95% confidence interval [CI]: 0.57, 0.94) and a specificity of 0.80 (95% CI: 0.66, 0.88). The combination of Cho/Cr and NAA/Cho ratios measured in the posterior periventricular white matter at term-equivalent age is predictive of motor outcome at 1 year in infants born at less than 32 weeks gestation. RSNA, 2013

Metabolite differences in the lenticular nucleus in type 2 diabetes mellitus shown by proton MR spectroscopy.

PubMed

Lin, Y; Zhou, J; Sha, L; Li, Y; Qu, X; Liu, L; Chen, H; An, Z; Wang, Y; Sun, C

2013-09-01

Previous studies by using proton MR spectroscopy found metabolite abnormalities in the cerebral cortex and white matter of patients with type 2 diabetes mellitus. The present study was undertaken to detect metabolite differences in the lenticular nuclei and thalamus in patients with T2DM. Twenty subjects with T2DM and 22 age-matched control subjects underwent single-voxel MR spectroscopy in the left and right lenticular nuclei and left and right thalami. NAA/Cr and Cho/Cr ratios were calculated. Brain lactic acid, fasting blood glucose, and glycosylated hemoglobin levels were also monitored. The NAA/Cr ratio was lower in the left lenticular nuclei of subjects with T2DM (P = .007), whereas the Cho/Cr ratio was increased in both the and right lenticular nuclei (P = .001). The NAA/Cr ratio was negatively correlated with FBG in the left (r = -0.573, P = .008) and right nuclei (r = -0.564, P = .010). It was also negatively correlated to HbA1c in the left (r = -0.560, P = .010) and right (r = -0.453, P = .045) nuclei. The Cho/Cr ratio was positively correlated with these variables (P < .05). No significant differences in NAA/Cr or Cho/Cr ratios were observed in the thalamus of patients with T2DM. Lactic acid was not detected in any of the patients in the study. The different metabolic statuses of the lenticular nuclei and thalamus suggest different effects of T2DM in each of these brain nuclei, with the lenticular nuclei being more vulnerable than the thalamus. The abnormal metabolic status was observed before lesions had appeared in these brain areas.

Ion exchange separation of chromium from natural water matrix for stable isotope mass spectrometric analysis

USGS Publications Warehouse

Ball, J.W.; Bassett, R.L.

2000-01-01

A method has been developed for separating the Cr dissolved in natural water from matrix elements and determination of its stable isotope ratios using solid-source thermal-ionization mass spectrometry (TIMS). The separation method takes advantage of the existence of the oxidized form of Cr as an oxyanion to separate it from interfering cations using anion-exchange chromatography, and of the reduced form of Cr as a positively charged ion to separate it from interfering anions such as sulfate. Subsequent processing of the separated sample eliminates residual organic material for application to a solid source filament. Ratios for 53Cr/52Cr for National Institute of Standards and Technology Standard Reference Material 979 can be measured using the silica gel-boric acid technique with a filament-to-filament standard deviation in the mean 53Cr/52Cr ratio for 50 replicates of 0.00005 or less. (C) 2000 Elsevier Science B.V. All rights reserved.

The Mn-53-Cr-53 System in CAIs: An Update

NASA Technical Reports Server (NTRS)

Papanastassiou, D. A.; Wasserburg, G. J.; Bogdanovski, O.

2005-01-01

High precision techniques have been developed for the measurement of Cr isotopes on the Triton mass spectrometer, at JPL. It is clear that multiple Faraday cup, simultaneous ion collection may reduce the uncertainty of isotope ratios relative to single Faraday cup ion collection, by the elimination of uncertainties from ion beam instabilities (since ion beam intensities for single cup collection are interpolated in time to calculate isotope ratios), and due to a greatly increased data collection duty cycle, for simultaneous ion collection. Efforts to measure Cr by simultaneous ion collection have not been successful in the past. Determinations on Cr-50-54Cr, by simultaneous ion collection on the Finnigan/ MAT 262 instrument at Caltech, resulted in large variations in extrinsic precision, for normal Cr, of up to 1% in Cr-53/Cr-52 (data corrected for mass fractionation, using Cr-50/Cr-52).

Proton Magnetic Resonance Spectroscopy Study on the Metabolism Changes of Cerebellum in Patients with Post-Stroke Depression.

PubMed

Zhang, Lei; Sui, Ru-Bo

2017-01-01

To study the metabolic changes of cerebellum by proton magnetic resonance Spectroscopy (1H-MRS) and discuss the relationships between the cerebellar changes and depression severity in patients with post-stroke depression. Data of demographic characteristics, individual history and life style of all subjects were collected. 40 patients with stroke and 20 controls were enrolled. All groups received T1WI, T2WI, DWI and 1H-MRS examination. The cerebral infarction volume and the distribution and severity of leukoaraiosis were evaluated. The ratios of NAA/Cr, Cho/Cr and Cho/NAA in the cerebellum were calculated. There were no statistical significant difference in the NAA/Cr, Cho/Cr and Cho/NAA ratios in bilateral cerebellum between CONT group and NORM group. The Cho/Cr and Cho/NAA ratios in the cerebellum contralateral to the stroke region were higher in PSD group than those in NORM and CONT groups, and the Cho/Cr and Cho/NAA ratios in the cerebellum ipsilateral to the stroke region were similar with those in NORM and CONT groups. However, there were no statistical significant difference in the NAA/Cr ratios in bilateral cerebellum among three groups. The result shows preliminarily that the cerebellum involves in the development of post-stroke depression. © 2017 The Author(s). Published by S. Karger AG, Basel.

The effect of organic compounds in the oxidation kinetics of Cr(III) by H 2O 2

NASA Astrophysics Data System (ADS)

Pettine, Maurizio; Gennari, Francesca; Campanella, Luigi; Millero, Frank J.

2008-12-01

The oxidation of Cr(III) has been studied in NaCl solutions in the presence of two siderophore models, acetohydroxamic acid (Aha) and benzohydroxamic acid (Bha), the natural siderophore Desferal (DFOB) and the synthetic aminocarboxilate (ethylenedinitrilo)-tetra-acetic acid (EDTA) as a function of pH (8-9), ionic strength (0.01-2 M) and temperature (10-50 °C), at different Cr(III)-organic compound ratios. The addition of Aha and Bha caused the rates to increase at low ligand/Cr(III) ratios and decrease at high ratios. The variation of the pseudo first order rate constant ( k1) as a function of the ligand concentration has been attributed to the formation of three Cr(III)-organo species (1:1, 1:2, 1:3), which can form in the presence of monohydroxamic acids. A kinetic model has been developed that gives a value of 600 (min -1) for the pseudo first order rate constant k and values approaching zero for k and k. These kinetic results demonstrate that these monohydroxamic acids are able to bind with Cr(III) under experimental conditions that may occur in natural waters and can increase the oxidation rates of Cr(III) with H 2O 2 by a factor of 3.5 at an Aha/Cr(III) ratio of about 50-100. The monohydroxamic acids also affect the rates on aged products of Cr(III), suggesting that these ligands are able to affect the oxidation rates by releasing reactive Cr(III). DFOB and EDTA do not have a great effect on the oxidation of Cr(III) with H 2O 2. This is thought to be due to the much longer times they need to form complexes with Cr(III) compared to Aha and Bha. The rates for the formation of DFOB and EDTA complexes with Cr(III) are not competitive with the rates of the formation of aged Cr(III). After allowing Cr(III) and DFOB to react for 5 days to form the complex, reaction rates of Cr(III) with H 2O 2 appear to be lowered probably because of steric hindrance of the chelated Cr(III).

Local H i emissivity measured with FERMI-LAT and implications for Cosmic-ray spectra

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

Casandjian, Jean -Marc

Cosmic-ray (CR) electrons and nuclei interact with the Galactic interstellar gas and produce high-energy γ-rays. The γ-ray emission rate per hydrogen atom, called emissivity, provides a unique indirect probe of the CR flux. We present the measurement and the interpretation of the emissivity in the solar neighborhood for γ-ray energy from 50 MeV to 50 GeV. We analyzed a subset of 4 yr of observations from the Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope ( Fermi) restricted to absolute latitudesmore » $$10^\\circ \\lt | b| \\lt 70^\\circ $$. From a fit to the LAT data including atomic, molecular, and ionized hydrogen column density templates, as well as a dust optical depth map, we derived the emissivities, the molecular hydrogen–to–CO conversion factor $${X}_{\\mathrm{CO}}=(0.902\\pm 0.007)\\times {10}^{20}$$ cm–2 (K km s–1)–1, and the dust-to-gas ratio $${X}_{\\mathrm{DUST}}=(41.4\\pm 0.3)\\times {10}^{20}$$ cm–2 mag–1. Moreover, we detected for the first time γ-ray emission from ionized hydrogen. We compared the extracted emissivities to those calculated from γ-ray production cross sections and to CR spectra measured in the heliosphere. We observed that the experimental emissivities are reproduced only if the solar modulation is accounted for. This provides a direct detection of solar modulation observed previously through the anticorrelation between CR fluxes and solar activity. Lastly, we fitted a parameterized spectral form to the heliospheric CR observations and to the Fermi-LAT emissivity and obtained compatible local interstellar spectra for proton and helium kinetic energy per nucleon between between 1 and 100 GeV and for electron–positrons between 0.1 and 100 GeV.« less

Local H i emissivity measured with FERMI-LAT and implications for Cosmic-ray spectra

DOE PAGES

Casandjian, Jean -Marc

2015-06-20

Cosmic-ray (CR) electrons and nuclei interact with the Galactic interstellar gas and produce high-energy γ-rays. The γ-ray emission rate per hydrogen atom, called emissivity, provides a unique indirect probe of the CR flux. We present the measurement and the interpretation of the emissivity in the solar neighborhood for γ-ray energy from 50 MeV to 50 GeV. We analyzed a subset of 4 yr of observations from the Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope ( Fermi) restricted to absolute latitudesmore » $$10^\\circ \\lt | b| \\lt 70^\\circ $$. From a fit to the LAT data including atomic, molecular, and ionized hydrogen column density templates, as well as a dust optical depth map, we derived the emissivities, the molecular hydrogen–to–CO conversion factor $${X}_{\\mathrm{CO}}=(0.902\\pm 0.007)\\times {10}^{20}$$ cm–2 (K km s–1)–1, and the dust-to-gas ratio $${X}_{\\mathrm{DUST}}=(41.4\\pm 0.3)\\times {10}^{20}$$ cm–2 mag–1. Moreover, we detected for the first time γ-ray emission from ionized hydrogen. We compared the extracted emissivities to those calculated from γ-ray production cross sections and to CR spectra measured in the heliosphere. We observed that the experimental emissivities are reproduced only if the solar modulation is accounted for. This provides a direct detection of solar modulation observed previously through the anticorrelation between CR fluxes and solar activity. Lastly, we fitted a parameterized spectral form to the heliospheric CR observations and to the Fermi-LAT emissivity and obtained compatible local interstellar spectra for proton and helium kinetic energy per nucleon between between 1 and 100 GeV and for electron–positrons between 0.1 and 100 GeV.« less

Metabolite ratios to assumed stable creatine level may confound the quantification of proton brain MR spectroscopy.

PubMed

Li, Belinda S Y; Wang, Hao; Gonen, Oded

2003-10-01

In localized brain proton MR spectroscopy ((1)H-MRS), metabolites' levels are often expressed as ratios, rather than as absolute concentrations. Frequently, their denominator is the creatine [Cr], which level is explicitly assumed to be stable in normal as well as in many pathologic states. The rationale is that ratios self-correct for imager and localization method differences, gain instabilities, regional susceptibility variations and partial volume effects. The implicit assumption is that these benefits are worth their cost(w)-(w) propagation of the individual variation of each of the ratio's components. To test this hypothesis, absolute levels of N-acetylaspartate [NAA], choline [Cho] and [Cr] were quantified in various regions of the brains of 8 volunteers, using 3-dimensional (3D) (1)H-MRS at 1.5 T. The results show that in over 50% of approximately 2000 voxels examined, [NAA]/[Cr] and [Cho]/[Cr] exhibited higher coefficients of variations (CV) than [NAA] and [Cho] individually. Furthermore, in approximately 33% of these voxels, the ratios' CVs exceeded even the combined constituents' CVs. Consequently, basing metabolite quantification on ratios and assuming stable [Cr] introduces more variability into (1)H-MRS than it prevents. Therefore, its cost exceeds the benefit.

Measurement of urinary 11-dehydro-thromboxane B2 excretion in dogs with gastric dilatation-volvulus.

PubMed

Baltzer, Wendy I; McMichael, Maureen A; Ruaux, Craig G; Noaker, Laura; Steiner, Jörg M; Williams, David A

2006-01-01

To measure 11-dehydro-thromboxane B2 (11-dTXB2) in urine of healthy control dogs, dogs undergoing ovariohysterectomy, and dogs with gastric dilatation-volvulus (GDV) and assess the relationship between urinary 11-dTXB2 concentrations in dogs with GDV and postoperative outcomes. Urine samples from 15 nonsurgical control dogs, 12 surgical control dogs, and 32 dogs with GVD. Urine samples were obtained from healthy pet dogs (ie, nonsurgical control dogs), dogs undergoing ovariohysterectomy at anesthetic induction and 1 hour following surgery (ie, surgical control dogs), and dogs with GDV at hospital admission and 1 hour following surgical derotation of the stomach (ie, GDV dogs). Urinary 11-dTXB2 concentrations were determined with an ELISA and normalized to urinary creatinine (Cr) concentrations by calculation of the 11-dTXB2 -to-Cr ratio. Differences in median 11-dTXB2 -to-Cr ratios among dogs and before and after surgery were analyzed. Urinary 11-dTXB2-to-Cr ratios did not differ between nonsurgical control dogs and surgical control dogs before or after surgery. Urinary 11-dTXB2-to-Cr ratios were significantly higher in GDV dogs at the time of hospital admission and 1 hour after surgery, compared with those of nonsurgical control dogs. Postoperative urine samples from GDV dogs had significantly higher 11-dTXB2-to-Cr ratios than postoperative urine samples from surgical control dogs. Median urinary 11-dTXB2-to-Cr ratios increased significantly in GDV dogs that developed postoperative complications. Urinary 11-dTXB2 concentration is increased in GDV dogs at the time of hospital admission and after surgical derotation of the stomach, compared with that of healthy dogs. An increased urinary 11-dTXB2-to-Cr ratio following surgery is associated with an increased incidence of postoperative complications in dogs with GDV.

Glutamate-glutamine and GABA in brain of normal aged and patients with cognitive impairment.

PubMed

Huang, Dandan; Liu, Dan; Yin, Jianzhong; Qian, Tianyi; Shrestha, Susan; Ni, Hongyan

2017-07-01

To explore the changes of glutamate-glutamine (Glx) and gamma-aminobutyric acid (GABA) in the brain in normal old age and cognitive impairment using magnetic resonance spectroscopy (MRS). Seventeen normal young controls (NYC), 15 normal elderly controls (NEC), 21 patients with mild cognitive impairment (MCI) and 17 with Alzheimer disease (AD) patients were included in this study. Glx and GABA+ levels in the anterior cingulate cortex (ACC) and right hippocampus (rHP) were measured by using a MEGA-PRESS sequence. Glx/Cr and GABA+/Cr ratios were compared between NYC and NEC and between the three elderly groups using analysis of covariance (ANCOVA); the tissue fractions of voxels were used as covariates. The relationships between metabolite ratios and cognitive performance were analysed using Spearman correlation coefficients. For NEC and NYC groups, Glx/Cr and GABA+/Cr ratios were lower in NEC in ACC and rHP. For the three elderly groups, Glx/Cr ratio was lower in AD in ACC compared to NEC and MCI; Glx/Cr ratio was lower in AD in rHP compared to NEC. There was no significant decrease for GABA+/Cr ratio. Glx and GABA levels may decrease simultaneously in normal aged, and Glx level decreased predominantly in AD, and it is helpful in the early diagnosis of AD. • Glx and GABA levels may decrease simultaneously in normal aged. • Glx level may decrease predominantly in Alzheimer disease. • The balance in excitatory-inhibitory systems may be broken in AD. • Decreased Glx level may be helpful in early diagnosis of AD.

Accuracy and equivalence testing of crown ratio models and assessment of their impact on diameter growth and basal area increment predictions of two variants of the Forest Vegetation Simulator

Treesearch

Laura P. Leites; Andrew P. Robinson; Nicholas L. Crookston

2009-01-01

Diameter growth (DG) equations in many existing forest growth and yield models use tree crown ratio (CR) as a predictor variable. Where CR is not measured, it is estimated from other measured variables. We evaluated CR estimation accuracy for the models in two Forest Vegetation Simulator variants: the exponential and the logistic CR models used in the North...

Hippocampal metabolic dysfunction in juvenile myoclonic epilepsy: 3D multivoxel spectroscopy study.

PubMed

Ristić, Aleksandar J; Ostojić, Jelena; Kozić, Duško; Vojvodić, Nikola M; Popović, Ljubica M; Janković, Slavko; Baščarević, Vladimir; Sokić, Dragoslav V

2011-06-15

To investigate the metabolic differences in hippocampi of patients with juvenile myoclonic epilepsy (JME) and healthy controls using magnetic resonance spectroscopy (MRS). A 3D multivoxel SE 135 MRS study on 1.5 T scanner of both hippocampi was performed in 17 patients with JME and normal brain MRI and in 19 age and sex matched controls. Three dominant signals were measured: Choline (Cho), Creatine (tCr) and N-Acetylaspartate (NAA) and expressed as ratios of Cho:tCr, NAA:tCr, NAA:Cho and NAA:(Cho+tCr). Metabolite ratios in head, body and tail of each hippocampus in the JME group of patients were compared with ratios from corresponding structures in the control group. We found a significant difference in metabolite ratios of both hippocampi between the JME and the control groups. We detected significant differences of Cho:tCr in the head, NAA:tCr in the head, body and tail, NAA:Cho and NAA:(Cho+tCr) in the body and tail of the left hippocampus, and NAA:Cho and NAA:(Cho+tCr) in the body and tail of the right hippocampus. Although not previously recognized as a part of the epileptogenic network, our results suggest that the hippocampus, well recognized as a key player in focal epilepsies, may have a certain role in the pathogenesis of JME. Copyright © 2010. Published by Elsevier B.V.

Standardization of Alternatives to Cadmium Plating for Electrical and Fiber Optic Connectors (Briefing Charts)

DTIC Science & Technology

2012-08-01

with trivalent conversion coat, was recently added to MIL-DTL-55181 (Note: The corrosion requirement for 55181 is 48 hours (non-dynamic), as...for Class W, OD-Cd with Hexavalent Chromium (Cr6+) top coat Olive-Drab Cadmium finish requirements (Note: Passivation process with a Cr6

Conversion to dementia in mild cognitive impairment diagnosed with DSM-5 criteria and with Petersen's criteria.

PubMed

Marcos, G; Santabárbara, J; Lopez-Anton, R; De-la-Cámara, C; Gracia-García, P; Lobo, E; Pírez, G; Menchón, J M; Palomo, T; Stephan, B C M; Brayne, C; Lobo, A

2016-05-01

In a background of revision of criteria for states of increased risk for progression to dementia, we compare the conversion rate to dementia and Alzheimer's disease (AD) of mild cognitive impairment (MCI) as diagnosed using DSM-5 (DSM-5-MCI) and Petersen's (P-MCI) criteria. A population representative cohort of 4057 dementia-free individuals 55+ years of age was followed up at 2.5 and 4.5 years in Zaragoza, Spain (ZARADEMP). Using the Geriatric Mental State- AGECAT for assessment, research psychiatrists diagnosed DSM-5-MCI and P-MCI following operationalized criteria. 'Conversion rate' (CR), 'annual conversion rate' (ACR), and incidence rate (IR) were calculated along with incidence rate ratio (IRR) to compare the performance of the intermediate cognitive definitions. At 4.5-year follow-up, in individuals aged 65+ years, ACRs for non-cases, P-MCI, and DSM-5-MCI were 0.8, 1.9 and 3.4, respectively, for global dementia. The IRRs were 2.9 and 5.3 for P-MCI and DSM5-MCI, respectively, being the non-cases the reference category. The corresponding values were slightly lower for AD. Conversion rate to dementia and AD was higher using DSM-5-MCI criteria than using Petersen's criteria. However, prediction of the construct still has some way to go, as most MCI individuals did not convert at 4.5-year follow-up. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effects of electroacupuncture on metabolic changes in motor cortex and striatum of 6-hydroxydopamine-induced Parkinsonian rats.

PubMed

Li, Min; Wang, Ke; Su, Wen-Ting; Jia, Jun; Wang, Xiao-Min

2017-10-06

To explore the possible underlying mechanism by investigating the effect of electroacupuncture (EA) treatment on the primary motor cortex and striatum in a unilateral 6-hydroxydopamine (6-OHDA) induced rat Parkinson's disease (PD) model. Male Sprague-Dawley rats were randomly divided into sham group (n=16), model group (n=14), and EA group (n=14). EA stimulation at Dazhui (GV 14) and Baihui (GV20) was applied to PD rats in the EA group for 4 weeks. Behavioral tests were conducted to evaluate the effectiveness of EA treatment. Metabolites were detected by 7.0 T proton nuclear magnetic resonance. Following 4 weeks of EA treatment in PD model rats, the abnormal behavioral impairment induced by 6-OHDA was alleviated. In monitoring changes in metabolic activity, ratios of myoinositol/creatine (Cr) and N-acetyl aspartate (NAA)/Cr in the primary motor cortex were significantly lower at the injected side than the non-injected side in PD rats (P=0.024 and 0.020). The ratios of glutamate + glutamine (Glx)/Cr and NAA/Cr in the striatum were higher and lower, respectively, at the injected side than the non-injected side (P=0.046 and 0.008). EA treatment restored the balance of metabolic activity in the primary motor cortex and striatum. In addition, the taurine/Cr ratio and Glx/Cr ratio were elevated in the striatum of PD model rats compared to sham-lesioned rats (P=0.026 and 0.000). EA treatment alleviated the excessive glutamatergic transmission by down-regulating the striatal Glx/Cr ratio (P=0.001). The Glx/Cr ratio was negatively correlated with floor plane spontaneous locomotion in PD rats (P=0.027 and P=0.0007). EA treatment is able to normalize the metabolic balance in the primary motor cortex and striatum of PD rats, which may contribute to its therapeutic effect on motor deficits. The striatal Glx/Cr ratio may serve as a potential indicator of PD and a therapeutic target of EA treatment.

Chromium isotopic homogeneity between the Moon, the Earth, and enstatite chondrites

NASA Astrophysics Data System (ADS)

Mougel, Bérengère; Moynier, Frédéric; Göpel, Christa

2018-01-01

Among the elements exhibiting non-mass dependent isotopic variations in meteorites, chromium (Cr) has been central in arguing for an isotopic homogeneity between the Earth and the Moon, thus questioning physical models of Moon formation. However, the Cr isotopic composition of the Moon relies on two samples only, which define an average value that is slightly different from the terrestrial standard. Here, by determining the Cr isotopic composition of 17 lunar, 9 terrestrial and 5 enstatite chondrite samples, we re-assess the isotopic similarity between these different planetary bodies, and provide the first robust estimate for the Moon. In average, terrestrial and enstatite samples show similar ε54Cr. On the other hand, lunar samples show variables excesses of 53Cr and 54Cr compared to terrestrial and enstatite chondrites samples with correlated ε53Cr and ε54Cr (per 10,000 deviation of the 53Cr/52Cr and 54Cr/52Cr ratios normalized to the 50Cr/52Cr ratio from the NIST SRM 3112a Cr standard). Unlike previous suggestions, we show for the first time that cosmic irradiation can affect significantly the Cr isotopic composition of lunar materials. Moreover, we also suggest that rather than spallation reactions, neutron capture effects are the dominant process controlling the Cr isotope composition of lunar igneous rocks. This is supported by the correlation between ε53Cr and ε54Cr, and 150Sm/152Sm ratios. After correction of these effects, the average ε54Cr of the Moon is indistinguishable from the terrestrial and enstatite chondrite materials reinforcing the idea of an Earth-Moon-enstatite chondrite system homogeneity. This is compatible with the most recent scenarios of Moon formation suggesting an efficient physical homogenization after a high-energy impact on a fast spinning Earth, and/or with an impactor originating from the same reservoir in the inner proto-planetary disk as the Earth and enstatite chondrites and having similar composition.

Serum and urine chromium as indices of chromium status in tannery workers

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

Randall, J.A.; Gibson, R.S.

Serum and urinary Cr levels of a selected group of men exposed to CrIII in four Southern Ontario tanneries were compared with those of men not exposed to Cr. Fasted blood samples were obtained from 72 tannery workers (TW; mean age +/- SD = 36 +/- 12 years) and from 52 controls (CS; mean age +/- SD = 41 +/- 13 years). Serum Cr levels as determined by graphite furnace atomic absorption spectrophotometry were significantly higher (P = 0.0001) for TW (median 0.49 ng/ml, range 0.37-0.81) than for CS (median 0.15 ng/ml, range 0.12-0.20). Urine samples were collected from 49more » TW and 43 CS on a Friday pm and from 42 TW on a Monday am. Urinary creatine (Cre) was determined by the Jaffe reaction. For Friday samples, the median urinary Cr/Cre ratio was significantly higher (P = 0.0001) for TW (median 0.83 ng/mg, range 0.48-1.82) than for CS (median 0.18 ng/mg, range 0.13-0.26). For TW, Cr/Cre was correlated with serum Cr (r = 0.72, P = 0.0001). Neither urinary Cr/Cre nor serum Cr was correlated with length of employment in the tanning industry. There were significant differences in serum Cr levels and urinary Cr/Cre ratios among TW employed in different areas of the tanneries. For TW, the median urinary Cr/Cre ratio for Monday morning samples was significantly lower than for Friday afternoon samples (P = 0.03). These data indicate that CrIII is absorbed and that serum and urine Cr in tannery workers may be indices of Cr exposure and status.« less

Serum and urine chromium as indices of chromium status in tannery workers.

PubMed

Randall, J A; Gibson, R S

1987-05-01

Serum and urinary Cr levels of a selected group of men exposed to CrIII in four Southern Ontario tanneries were compared with those of men not exposed to Cr. Fasted blood samples were obtained from 72 tannery workers (TW; mean age +/- SD = 36 +/- 12 years) and from 52 controls (CS; mean age +/- SD = 41 +/- 13 years). Serum Cr levels as determined by graphite furnace atomic absorption spectrophotometry were significantly higher (P = 0.0001) for TW (median 0.49 ng/ml, range 0.37-0.81) than for CS (median 0.15 ng/ml, range 0.12-0.20). Urine samples were collected from 49 TW and 43 CS on a Friday pm and from 42 TW on a Monday am. Urinary creatine (Cre) was determined by the Jaffe reaction. For Friday samples, the median urinary Cr/Cre ratio was significantly higher (P = 0.0001) for TW (median 0.83 ng/mg, range 0.48-1.82) than for CS (median 0.18 ng/mg, range 0.13-0.26). For TW, Cr/Cre was correlated with serum Cr (r = 0.72, P = 0.0001). Neither urinary Cr/Cre nor serum Cr was correlated with length of employment in the tanning industry. There were significant differences in serum Cr levels and urinary Cr/Cre ratios among TW employed in different areas of the tanneries. For TW, the median urinary Cr/Cre ratio for Monday morning samples was significantly lower than for Friday afternoon samples (P = 0.03). These data indicate that CrIII is absorbed and that serum and urine Cr in tannery workers may be indices of Cr exposure and status.

Effect of feeding sorghum straw based complete rations with different roughage to concentrate ratio on dry matter intake, nutrient utilization, and nitrogen balance in Nellore ram lambs.

PubMed

Malisetty, Venkateswarlu; Yerradoddi, Ramana Reddy; Devanaboina, Nagalakshmi; Mallam, Mahender; Mitta, Pavani

2014-06-01

An experiment was conducted by feeding sorghum straw (Sorghum bicolor) based complete rations at roughage concentrate ratio 70:30 (CR-I), 60:40 (CR-II), 50:50 (CR-III), and 40:60 (CR-IV) for 180 days to find out suitable ratio of sorghum straw in the complete ration (mash form) on nutrient utilization and nitrogen balance in Nellore ram lambs. The DMI (g/day) increased significantly (P < 0.05) as level of concentrate increased in complete rations. No significant difference was found in digestibilities of proximate nutrients. However, CP digestibility was higher either significantly or nonsignificantly by 2.12, 5.50, and 9.36 %, respectively, in lambs fed with CR-II (P > 0.05), CR-III (P > 0.05), and CR-IV (P < 0.05) rations in comparison to lambs fed with CR-I ration. Furthermore, CP digestibility was higher by 7.09 and 3.66 % in lambs fed with CR-IV ration than those fed with CR-II (P < 0.05) and CR-III (P > 0.05) ration. The average CWC digestibility coefficients were comparable among four rations. The N intake (g/day) was significantly (P < 0.01) different and progressively increased by 31.46, 48.69, and 82.86 % in ram lambs fed with CR-II, CR-III, and CR-IV rations, respectively, in comparison to CR-I ration. The N balance (g/day) was higher either significantly or nonsignificantly by 34.46 (P > 0.05), 133.46 (P < 0.01), and 198.87 % (P < 0.01) with CR-II, CR-III, and CR-IV rations, respectively, in comparison to CR-I ration. Based on results, it is inferred that the level of sorghum straw in complete ration had no effect on digestibility of nutrients barring crude protein in Nellore ram lambs.

Study of multi-kW solar arrays for Earth orbit application

NASA Technical Reports Server (NTRS)

1980-01-01

Planar and concentrator solar array configurations based on silicon and gallium arsenide solar cells were conceptualized and on-orbit maintainability was addressed. Four basic categories emerged: (1) planar (non concentrated) with silicon cells, (2) low-CR (concentration ratio = 3.4) with silicon cells, (3) low-CR with GaAs, and (4) high-CR (concentration ratio = 62.5) with GaAs. A very high-CR (concentration ratio = 200) was investigated but rejected on thermal grounds. Nonrecurring and recurring cost elements for each of the four concepts selected were compared over a 15 year life cycle. Under conditions where the gallium arsenide cells can be produced for less than $25 per 2 x 2 cm, the low CR concentrator emerges as the most cost effective configuration. However, the producibility risk remains higher on the gallium arsenide cell.

Remediation of Cr(VI)-Contaminated Soil Using the Acidified Hydrazine Hydrate.

PubMed

Ma, Yameng; Li, Fangfang; Jiang, Yuling; Yang, Weihua; Lv, Lv; Xue, Haotian; Wang, Yangyang

2016-09-01

Acidified hydrazine hydrate was used to remediate Cr(VI)-contaminated soil. The content of water-soluble Cr(VI) in contaminated soil was 4977.53 mg/kg. The optimal initial pH of hydrazine hydrate solution, soil to solution ratio and molar ratio of Cr(VI) to hydrazine hydrate for remediation of Cr(VI)-contaminated soil were 5.0, 3:1 and 1:3, respectively. Over 99.50 % of water-soluble Cr(VI) in the contaminated soil was reduced at the optimal condition within 30 min. The remediated soil can keep stable within 4 months. Meanwhile the total phosphorus increased from 0.47 to 4.29 g/kg, indicating that using of acidified hydrazine hydrate is an effective method to remediate Cr(VI)-contaminated soil.

Transition metal sulfide loaded catalyst

DOEpatents

Maroni, Victor A.; Iton, Lennox E.; Pasterczyk, James W.; Winterer, Markus; Krause, Theodore R.

1994-01-01

A zeolite based catalyst for activation and conversion of methane. A zeolite support includes a transition metal (Mo, Cr or W) sulfide disposed within the micropores of the zeolite. The catalyst allows activation and conversion of methane to C.sub.2 + hydrocarbons in a reducing atmosphere, thereby avoiding formation of oxides of carbon.

Proton magnetic resonance spectroscopic findings of cerebral fat embolism induced by triolein emulsion in cats.

PubMed

Baik, S K; Kim, Y-W; Kim, H J; Lee, J W; Cho, B M; Kim, D-H; Choi, S H; Lee, S H; Chang, K H

2008-12-01

In experimental studies, embolization of the cerebral hemisphere with triolein emulsion has revealed reversible magnetic resonance imaging (MRI) findings in the subacute stage. To investigate the changes in the major metabolites, by proton magnetic resonance spectroscopy (MRS), in a cerebral fat embolism induced by a triolein emulsion. The internal carotid arteries of 19 cats were injected with a triolein emulsion, and multivoxel MRS was performed 30 min, 1 day, and 7 days later. In the control group, six cats were injected with normal saline. The MR spectra were evaluated for N-acetyl aspartate (NAA), creatine (Cr), and choline (Cho), along with the presence of lipid and lactate. Semiquantitative analyses of NAA/Cr, Cho/Cr, NAA/Cho, and lipid/Cr ratios compared the median values of the ipsilateral metabolite ratios with those of the contralateral side and in the control group for each point in time. The NAA/Cr, Cho/Cr, and NAA/Cho ratios in the ipsilateral cerebral hemisphere of the embolized group after 30 min, 1 day, and 7days were not significantly different from the contralateral hemisphere of the embolized and control groups (P>0.05). The lipid/Cr ratio in the ipsilateral cerebral hemisphere of the embolized group was significantly higher when compared with the control group (P=0.012 at 30 min, P=0.001 on day 1, and P=0.018 on day 7). Cerebral fat embolism induced by a triolein emulsion resulted in no significant change in the major metabolites of the brain in the acute stage, except for an elevated lipid/Cr ratio, which suggests the absence of any significant hypoxic-ischemic changes in the lesions embolized using a fat emulsion.

Low-cost, single-mode diode-pumped Cr:Colquiriite lasers.

PubMed

Demirbas, Umit; Li, Duo; Birge, Jonathan R; Sennaroglu, Alphan; Petrich, Gale S; Kolodziejski, Leslie A; Kaertner, Franz X; Fujimoto, James G

2009-08-03

We present three Cr3+:Colquiriite lasers as low-cost alternatives to Ti:Sapphire laser technology. Single-mode laser diodes, which cost only $150 each, were used as pump sources. In cw operation, with approximately 520 mW of absorbed pump power, up to 257, 269 and 266 mW of output power and slope efficiencies of 53%, 62% and 54% were demonstrated for Cr:LiSAF, Cr:LiSGaF and Cr:LiCAF, respectively. Record cw tuning ranges from 782 to 1042 nm for Cr:LiSAF, 777 to 977 nm for Cr:LiSGaF, and 754 to 871 nm for Cr:LiCAF were demonstrated. In cw mode-locking experiments using semiconductor saturable absorber mirrors at 800 and 850 nm, Cr:Colquiriite lasers produced approximately 50-100 fs pulses with approximately 1-2.5 nJ pulse energies at approximately 100 MHz repetition rate. Electrical-to-optical conversion efficiencies of 8% in mode-locked operation and 12% in cw operation were achieved.

Enstatite Meteorites and the Original Heterogeneity of Mn-53 Distribution in the Solar Nebula

NASA Technical Reports Server (NTRS)

Lugmair, Guenter W.

1999-01-01

We have shown earlier that the relative abundance of radiogenic Cr-53 in bulk ordinary chondrites (approximately 0.48 epsilon) is clearly different from that in the earth-moon system (0 epsilon). The SNC parent body (Mars) is characterized by an intermediate Cr-53 excess (approximately 0.23 epsilon). We have also shown that the Mn-Cr systematics of the howardite-eucrite-diogenite parent body (HED PB, the asteroid Vesta) is consistent with the chondritic Mn/Cr ratio in the bulk HED PB and that it has a Cr-53 excess of approximately 0.5 epsilon units which is within error the same as that of chondrites. It appears that the excesses of Cr-53 in these planets are a function of their present heliocentric distance. The study of some other meteorite classes (angrites, pallasites, primitive achondrites) has shown that their Mn-CR systematics is consistent with that of the ordinary chondrites. The observed gradient in the radiogenic Cr-53 abundances can be explained by a). an early volatility controlled radial Mn/Cr fractionation in the nebula or b). an original heterogeneity of Mn-53. The first assumption, however, requires the Mn/Cr ratios of the bulk Earth and Mars to be considerably lower than the inferred model Mn/Cr ratios for these two planets. For this reason, we suggested that the observed gradient is due to an original radial Mn-53 heterogeneity in the late nebula.

Corrosion and Wear Behaviors of Cr-Doped Diamond-Like Carbon Coatings

NASA Astrophysics Data System (ADS)

Viswanathan, S.; Mohan, L.; Bera, Parthasarathi; Kumar, V. Praveen; Barshilia, Harish C.; Anandan, C.

2017-08-01

A combination of plasma-enhanced chemical vapor deposition and magnetron sputtering techniques has been employed to deposit chromium-doped diamond-like carbon (DLC) coatings on stainless steel, silicon and glass substrates. The concentrations of Cr in the coatings are varied by changing the parameters of the bipolar pulsed power supply and the argon/acetylene gas composition. The coatings have been studied for composition, morphology, surface nature, nanohardness, corrosion resistance and wear resistance properties. The changes in I D / I G ratio with Cr concentrations have been obtained from Raman spectroscopy studies. Ratio decreases with an increase in Cr concentration, and it has been found to increase at higher Cr concentration, indicating the disorder in the coating. Carbide is formed in Cr-doped DLC coatings as observed from XPS studies. There is a decrease in sp 3/ sp 2 ratios with an increase in Cr concentration, and it increases again at higher Cr concentration. Nanohardness studies show no clear dependence of hardness on Cr concentration. DLC coatings with lower Cr contents have demonstrated better corrosion resistance with better passive behavior in 3.5% NaCl solution, and corrosion potential is observed to move toward nobler (more positive) values. A low coefficient of friction (0.15) at different loads is observed from reciprocating wear studies. Lower wear volume is found at all loads on the Cr-doped DLC coatings. Wear mechanism changes from abrasive wear on the substrate to adhesive wear on the coating.

Determination of the Cryolite Ratio of KF-NaF-AlF3 Electrolyte by Conductivity Method

NASA Astrophysics Data System (ADS)

Yan, Hengwei; Yang, Jianhong; Liu, Zhanwei; Wang, Chengzhi; Ma, Wenhui

2018-05-01

The cryolite ratio (CR) is an important parameter for the electrolyte in aluminum reduction cells. The measurement method for the CR of the KF-NaF-AlF3 system acid (CR < 3) electrolyte by means of electrical conductivity was initially developed, and the formula for calculating the CR was deduced. This method has the advantages of simple operation and high precision. In addition, the relative standard deviations (RSD) of the measurement are < 1.2 pct, and the analysis error of the NaF or KF content has little effect on the determination of the CR.

Electronic and Optical Properties of a Semiconducting Spinel (Fe 2 CrO 4 )

DOE PAGES

Chambers, Scott A.; Droubay, Timothy C.; Kaspar, Tiffany C.; ...

2017-01-13

Epitaxial chromium ferrite (Fe 2CrO 4), prepared by state-of-the-art oxygen plasma assisted molecular beam epitaxy, is shown to exhibit unusual electronic transport properties driven by the crystallographic structure and composition of the material. By replacing 1/3 of the Fe cations with Cr converts the host ferrimagnet from a metal into a semiconductor by virtue of its fixed valence (3+); Cr substitutes for Fe at B sites in the spinel lattice. Conversely, replacing 2/3 of the Fe cations with Cr results in an insulator. Three candidate conductive paths, all involving electron hopping between Fe 2+ and Fe 3+, are identified inmore » Fe 2CrO 4. Moreover, Fe 2CrO 4 is shown to be photoconductive across the visible portion of the electromagnetic spectrum. As a result, this material is of potential interest for important photo-electrochemical processes such as water splitting.« less

Reduced N-acetylaspartate to creatine ratio in the posterior cingulate correlates with cognition in Alzheimer's disease following four months of rivastigmine treatment.

PubMed

Penner, Jacob; Wells, Jennie L; Borrie, Michael J; Woolmore-Goodwin, Sarah M; Bartha, Robert

2015-01-01

To determine whether 4 months of rivastigmine treatment would result in metabolic changes and whether metabolic changes correlate with changes in cognition in people with Alzheimer's disease (AD). Magnetic resonance spectra were acquired from the posterior cingulate cortex of subjects with AD at 3 T. Magnetic resonance imaging scans and cognitive tests were performed before and 4 months after the beginning of the treatment. Metabolite concentrations were quantified and used to calculate the metabolite ratios. On average, the N-acetylaspartate/creatine (NAA/Cr) ratio decreased by 12.7% following 4 months of rivastigmine treatment, but changes in the NAA/Cr ratio correlated positively with changes in Mini-Mental State Examination scores. This positive correlation between changes in NAA/Cr and changes in cognitive performance suggests that the NAA/Cr ratio could be an objective indicator of a response to rivastigmine treatment. © 2014 S. Karger AG, Basel

Serum and urinary cystatin C in cats with feline immunodeficiency virus infection and cats with hyperthyroidism.

PubMed

Ghys, Liesbeth Fe; Paepe, Dominique; Taffin, Elien Rl; Vandermeulen, Eva; Duchateau, Luc; Smets, Pascale My; Delanghe, Joris; Daminet, Sylvie

2016-08-01

The objective of this study was to investigate serum cystatin C (sCysC) and urinary cystatin C (uCysC) in cats with hyperthyroidism and cats with feline immunodeficiency virus (FIV). Thirty cats with FIV, 26 hyperthyroid cats and 28 healthy cats were included. sCysC and uCysC:creatinine (uCysC/uCr) ratio were measured with a human particle-enhanced nephelometric immunoassay, previously validated for feline CysC measurement. Routine renal variables (serum creatinine [sCr], urine specific gravity, urinary protein:creatinine ratio [UPC]) were also measured in the three groups. Cats with hyperthyroidism had significantly higher sCysC and higher uCysC/uCr ratio, lower sCr and a higher UPC than healthy cats. Cats with FIV infection did not show a significantly higher sCysC concentration but had a significantly higher sCr and UPC than healthy cats. uCysC could be detected in only four of them. This study demonstrated that sCysC is increased in cats with hyperthyroidism, in contrast with sCr, but not in cats with FIV. Many hyperthyroid cats, but only four cats with FIV, had an elevated uCysC/uCr ratio. Further studies may reveal if uCysC might be a valuable marker for tubular dysfunction in cats. © The Author(s) 2015.

Effect of occupational manganese exposure on the central nervous system of welders: 1H magnetic resonance spectroscopy and MRI findings.

PubMed

Kim, Eun A; Cheong, Hae-Kwan; Choi, Dae Seob; Sakong, Joon; Ryoo, Jae Wook; Park, Injeong; Kang, Dong Mug

2007-03-01

This study investigated the relationship between long-term occupational manganese (Mn) exposure on the regional Mn concentration in the brain, neuronal loss, and neurobehavioral effects on welders. 1H MRS of the basal ganglia (BG) was performed on 20 male welders and 10 age- and gender-matched, non-office, control workers in a shipyard to assess the metabolic change, and the N-acetylaspartate (NAA)/creatine (Cr), choline (Cho)/Cr and NAA/Cho ratios, by the level of Mn exposure. We also assessed the signal intensity of T1-weighted image of magnetic resonance imaging (MRI) on globus pallidus (GP) compared to that of the frontal white matter (pallidal index, PI). The welders had significantly higher signal intensity than the controls. PI showed a significant dose-response relationship with cumulative exposure index (CEI) (r=0.54, p=0.002). CEI and PI showed different relationships with NAA/Cr according to smoking status, and the correlation was evident only in non-smokers (r=-0.73 and -0.57, respectively). There were no significant differences between the welders and the controls in NAA/Cr, Cho/Cr, and NAA/Cho ratios obtained from BG. CEI was positively correlated with simple reaction time. PI was positively correlated with mean sway (MSWAY), sway area (SWAYA), and sway intensity (SWAYI), and negatively correlated with maximum frequency (MAXF). After categorizing the subjects into two groups according to NAA/Cr ratio level, the low NAA/Cr ratio group showed significantly lower score on digit span backward and significantly higher score on MSWAY, SWAYA and SWAYI in regression analysis than the high NAA/Cr ratio group. We speculated that the NAA/Cr ratio of MRS in BG seems to reflect the cumulative effect of Mn exposure on the human brain. Due to uneven distribution of smoking among the welders and the controls, in addition to the small number of subjects in our study, our findings are needed further studies with a larger number of subjects.

Transport properties of high-performance all-Heusler Co2CrSi/Cu2CrAl/Co2CrSi giant magnetoresistance device

NASA Astrophysics Data System (ADS)

Bai, Z. Q.; Lu, Y. H.; Shen, L.; Ko, V.; Han, G. C.; Feng, Y. P.

2012-05-01

Transport properties of giant magnetoresistance (MR) junction consisting of trilayer Co2CrSi/Cu2CrAl/Co2CrSi Heusler alloys (L21) are studied using first-principles approach based on density functional theory and the non-equilibrium Green's function method. Highly conductive channels are found in almost the entire k-plane when the magnetizations of the electrodes are parallel, while they are completely blocked in the antiparallel configuration, which leads to a high magnetoresistance ratio (the pessimistic MR ratio is nearly 100%). Furthermore, the calculated I-V curve shows that the device behaves as a good spin valve with a considerable disparity in currents under the parallel and antiparallel magnetic configurations of the electrodes. The Co2CrSi/Cu2CrAl/Co2CrSi junction could be useful for high-performance all-metallic current-perpendicular-to-plane giant magnetoresistance reading head for the next generation high density magnetic storage.

Pyrolysis characteristics and kinetics of oil-based drilling cuttings in shale gas developing

NASA Astrophysics Data System (ADS)

Huang, Chuan; Li, Tong; Xu, Tengtun; Zeng, Yunmin; Song, Xue

2018-03-01

In this paper, the thermal behavior of waste oil-based drilling cuttings (from shale gas fields in Chongqing) was examined at different heating rates ranging from 5 to 15 °C min-1 in inert atmosphere using a sync analyzer of thermogravimetry (TG) and differential scanning calorimetry (DSC). Four methods were used to analyze the distributions and variations of kinetics parameter (active energy (E) and frequency gene (A)): Coats-Redfern and other three iso-conversion rate methods (Flynn-Wall-Ozawa, Vyazovkin and Friedman). The experimental results indicated that the process consists of three steps, i.e., water evaporation, volatilization of light oil component and heavy oil cracking. TG curves moved toward higher temperature zone caused by thermal hysteresis with the increase of temperature rising rate. For volatilization of lightweight components, the E calculated by three iso-conversion rate methods changed a little with conversion, and had almost the same results as the CR method (14.39˜20.08 kJ.mol-1). For reactions of heavy oil cracking with mixed mechanism, corresponding E rose gradually with the increase of reaction time. The CR method shows nonlinear trends and the reaction models and kinetic parameters cannot be extracted from CR curves. The results by three iso-conversion methods showed that apparent activation energy was given as 155.74˜561.10 kJ.mol-1, 141.06˜524.96 kJ.mol-1 and 74.37˜605.10 kJ.mol-1, respectively.

Accelerated Echo Planer J-resolved Spectroscopic Imaging of Putamen and Thalamus in Obstructive Sleep Apnea.

PubMed

Sarma, Manoj K; Macey, Paul M; Nagarajan, Rajakumar; Aysola, Ravi; Harper, Ronald M; Thomas, M Albert

2016-09-06

Obstructive sleep apnea syndrome (OSAS) leads to neurocognitive and autonomic deficits that are partially mediated by thalamic and putamen pathology. We examined the underlying neurochemistry of those structures using compressed sensing-based 4D echo-planar J-resolved spectroscopic imaging (JRESI), and quantified values with prior knowledge fitting. Bilaterally increased thalamic mI/Cr, putamen Glx/Cr, and Glu/Cr, and bilaterally decreased thalamic and putamen tCho/Cr and GABA/Cr occurred in OSAS vs healthy subjects (p < 0.05). Increased right thalamic Glx/Cr, Glu/Cr, Gln/Cr, Asc/Cr, and decreased GPC/Cr and decreased left thalamic tNAA/Cr, NAA/Cr were detected. The right putamen showed increased mI/Cr and decreased tCho/Cr, and the left, decreased PE/Cr ratio. ROC curve analyses demonstrated 60-100% sensitivity and specificity for the metabolite ratios in differentiating OSAS vs. Positive correlations were found between: left thalamus mI/Cr and baseline oxygen saturation (SaO2); right putamen tCho/Cr and apnea hypopnea index; right putamen GABA/Cr and baseline SaO2; left putamen PE/Cr and baseline SaO2; and left putamen NAA/Cr and SaO2 nadir (all p < 0.05). Negative correlations were found between left putamen PE/Cr and SaO2 nadir. These findings suggest underlying inflammation or glial activation, with greater alterations accompanying lower oxygen saturation. These metabolite levels may provide biomarkers for future neurochemical interventions by pharmacologic or other means.

Blood urea nitrogen/creatinine ratio identifies a high-risk but potentially reversible form of renal dysfunction in patients with decompensated heart failure.

PubMed

Brisco, Meredith A; Coca, Steven G; Chen, Jennifer; Owens, Anjali Tiku; McCauley, Brian D; Kimmel, Stephen E; Testani, Jeffrey M

2013-03-01

Identifying reversible renal dysfunction (RD) in the setting of heart failure is challenging. The goal of this study was to evaluate whether elevated admission blood urea nitrogen/creatinine ratio (BUN/Cr) could identify decompensated heart failure patients likely to experience improvement in renal function (IRF) with treatment. Consecutive hospitalizations with a discharge diagnosis of heart failure were reviewed. IRF was defined as ≥20% increase and worsening renal function as ≥20% decrease in estimated glomerular filtration rate. IRF occurred in 31% of the 896 patients meeting eligibility criteria. Higher admission BUN/Cr was associated with in-hospital IRF (odds ratio, 1.5 per 10 increase; 95% confidence interval [CI], 1.3-1.8; P<0.001), an association persisting after adjustment for baseline characteristics (odds ratio, 1.4; 95% CI, 1.1-1.8; P=0.004). However, higher admission BUN/Cr was also associated with post-discharge worsening renal function (odds ratio, 1.4; 95% CI, 1.1-1.8; P=0.011). Notably, in patients with an elevated admission BUN/Cr, the risk of death associated with RD (estimated glomerular filtration rate <45) was substantial (hazard ratio, 2.2; 95% CI, 1.6-3.1; P<0.001). However, in patients with a normal admission BUN/Cr, RD was not associated with increased mortality (hazard ratio, 1.2; 95% CI, 0.67-2.0; P=0.59; p interaction=0.03). An elevated admission BUN/Cr identifies decompensated patients with heart failure likely to experience IRF with treatment, providing proof of concept that reversible RD may be a discernible entity. However, this improvement seems to be largely transient, and RD, in the setting of an elevated BUN/Cr, remains strongly associated with death. Further research is warranted to develop strategies for the optimal detection and treatment of these high-risk patients.

Blood Urea Nitrogen/Creatinine Ratio Identifies a High-Risk but Potentially Reversible Form of Renal Dysfunction in Patients With Decompensated Heart Failure

PubMed Central

Brisco, Meredith A.; Coca, Steven G.; Chen, Jennifer; Owens, Anjali Tiku; McCauley, Brian D.; Kimmel, Stephen E.; Testani, Jeffrey M.

2014-01-01

Background Identifying reversible renal dysfunction (RD) in the setting of heart failure is challenging. The goal of this study was to evaluate whether elevated admission blood urea nitrogen/creatinine ratio (BUN/Cr) could identify decompensated heart failure patients likely to experience improvement in renal function (IRF) with treatment. Methods and Results Consecutive hospitalizations with a discharge diagnosis of heart failure were reviewed. IRF was defined as ≥20% increase and worsening renal function as ≥20% decrease in estimated glomerular filtration rate. IRF occurred in 31% of the 896 patients meeting eligibility criteria. Higher admission BUN/Cr was associated with inhospital IRF (odds ratio, 1.5 per 10 increase; 95% confidence interval [CI], 1.3–1.8; P<0.001), an association persisting after adjustment for baseline characteristics (odds ratio, 1.4; 95% CI, 1.1–1.8; P=0.004). However, higher admission BUN/Cr was also associated with post-discharge worsening renal function (odds ratio, 1.4; 95% CI, 1.1–1.8; P=0.011). Notably, in patients with an elevated admission BUN/Cr, the risk of death associated with RD (estimated glomerular filtration rate <45) was substantial (hazard ratio, 2.2; 95% CI, 1.6–3.1; P<0.001). However, in patients with a normal admission BUN/Cr, RD was not associated with increased mortality (hazard ratio, 1.2; 95% CI, 0.67–2.0; P=0.59; p interaction=0.03). Conclusions An elevated admission BUN/Cr identifies decompensated patients with heart failure likely to experience IRF with treatment, providing proof of concept that reversible RD may be a discernible entity. However, this improvement seems to be largely transient, and RD, in the setting of an elevated BUN/Cr, remains strongly associated with death. Further research is warranted to develop strategies for the optimal detection and treatment of these high-risk patients. PMID:23325460

Detection of human immunodeficiency virus induced inflammation and oxidative stress in lenticular nuclei with magnetic resonance spectroscopy despite antiretroviral therapy.

PubMed

Roc, Anne C; Ances, Beau M; Chawla, Sanjeev; Korczykowski, Marc; Wolf, Ronald L; Kolson, Dennis L; Detre, John A; Poptani, Harish

2007-09-01

Single-voxel magnetic resonance spectroscopy measurements of N-acetyl aspartate, choline, and creatine (Cr) are affected in patients with human immunodeficiency virus (HIV) and neurocognitive impairment. However, these metabolic markers are often normalized in affected central nervous system regions, such as the lenticular nuclei, after initiation of highly active antiretroviral therapy (HAART). To examine whether lactate (Lac), a marker of inflammation and anaerobic glycolysis, and lipid, an indicator of cell membrane turnover resulting from oxidative stress, could serve as surrogate biomarkers within the lenticular nuclei of HIV-positive patients with different degrees of neurocognitive impairment. Three-tesla 2-dimensional-chemical shift imaging magnetic resonance spectroscopy at echo times of 30 milliseconds and 135 milliseconds was performed in voxels overlapping the lenticular nuclei of seronegative controls and a spectrum of HIV-positive patients (neurocognitively normal, mildly impaired, or moderately to severely impaired). University of Pennsylvania, Philadelphia. Ten seronegative controls and 45 HIV-positive patients with different degrees of neurocognitive impairment (15 neurocognitively normal patients, 12 mildly impaired patients, and 18 moderately to severely impaired patients). In vivo 2-dimensional-chemical shift imaging magnetic resonance spectroscopy analysis of N-acetyl aspartate:Cr, choline:Cr, Lac:Cr, and (lipid + Lac):Cr ratios among the various groups. In addition, the effect of the degree of HAART central nervous system penetration (high vs low) on these ratios was studied. No significant lenticular nuclei atrophy was detected with volumes similar across all of the groups. Both N-acetyl aspartate:Cr and choline:Cr ratios were similar across all of the groups at either echo time. In contrast, the Lac:Cr ratio was significantly greater in HIV-positive patients with moderate to severe impairment compared with seronegative controls. The (lipid + Lac):Cr ratio was significantly elevated within each HIV-positive subgroup compared with seronegative controls. Within HIV-positive patients receiving HAART, the degree of central nervous system penetration (high vs low) did not affect metabolic ratios. As seen with 2-dimensional-chemical shift imaging magnetic resonance spectroscopy, HIV induces inflammation and oxidative stress in HIV-positive patients despite HAART. Lipid and Lac are more sensitive inflammatory biomarkers that may be used to differentiate HIV-positive subgroups. However, no significant difference in efficacy, as measured by metabolic ratios, exists for high- vs low-central nervous system-penetrating HAART.

The origin of chromitic chondrules and the volatility of Cr under a range of nebular conditions

NASA Technical Reports Server (NTRS)

Krot, Alexander; Ivanova, Marina A.; Wasson, John T.

1993-01-01

We characterize ten chromatic chondrules, two spinelian chondrules andd one spinel-bearing chondrule and summarize data for 120 chromitic inclusions discovered in an extensive survey of ordinary chondrites. Compositional and petrographic evidence suggests that chromitic chondrules and inclusions are closely related. The Cr/(Cr + Al) ratios in the spinal of these objects range from 0.5 to 0.9 and bulk Al2O3 contents are uniformly high (greater than 10 wt%, except for one with 8 wt%). No other elements having comparable solar abundances are so stongly enriched, and alkali feldspar and merrillite are more common than in normal chondrules. The Cr/Mg ratios in chromitic chondrules are 180-750 times the ratios in the bulk chondrite. With the possible exception of magnetic clumping of chromite in the presolar cloud, mechanical processes cannot account for this enrichment. Examination of nebular equilibrium processes shows that 50%-condensation temperatures of Cr at pH2/pH2O of 1500 are several tens of degrees below those of Mg as Mg2SiO4; the condensation of Cr is primarily as MgCr2O4 dissolved in MgAl2O4 at nebular pressures of 10(exp -4) atm or below. At pH2 = 10(exp -3) atm condesation as Cr in Fe-Ni is favored. Making the nebula much more oxidizing reduces the difference in condensation temperatures but Mg remains more refractory. We conclude that nebular equilibrium processes are not responsible for the enhanced Cr/Mg ratios. We propose that both Cr and Al became enriched in residues formed by incomplete evaporation of presolar lumps. We suggest that spinals remained as solid phases when the bulk of the silicates were incorporated into the evaporating melt; vaporization of Al and Cr were inhibited by the slow kinetics of diffusion. Subsequent melting and crystallization of these residues fractionated Cr from Al. The resulting materials constituted major components in the precursors of chromitic chondrules. Our model implies that chromitic chondrules and inclusions preserve the Cr isotopic record of presolar sources.

Regional metabolic changes in the hippocampus and posterior cingulate area detected with 3-Tesla magnetic resonance spectroscopy in patients with mild cognitive impairment and Alzheimer disease.

PubMed

Wang, Zhiqun; Zhao, Cheng; Yu, Lei; Zhou, Weidong; Li, Kuncheng

2009-04-01

Magnetic resonance spectroscopy (MRS) plays an important role in early diagnosis of Alzheimer disease (AD). There are many reports on MRS studies among individuals with AD and mild cognitive impairment (MCI). However, very few studies have compared spectroscopic data of different limbic regions among AD and MCI subjects. To compare metabolite changes of different regions in the brain of AD and MCI patients by using 3.0 T short-echo-time MRS. Metabolite ratios in the hippocampus and posterior cingulate area were compared in a group of patients with AD (n=16), MCI (n=16), and normal subjects as a control group (n=16). Clinical neuropsychological tests were measured in all subjects. In the hippocampus, there were significant differences in N-acetylaspartate (NAA)/creatine (Cr), myo-inositol (mI)/Cr, and mI/NAA ratios among the three groups. However, there were no significant differences in choline (Cho)/Cr ratio among the three groups. In the posterior cingulate area, there were no significant differences in the NAA/Cr, Cho/Cr, and mI/Cr ratios among the three groups. However, there were significant differences in mI/NAA ratio between patients with AD and the control group, and between the AD and MCI groups. In addition, there was significant correlation between mI/NAA ratio and Mini Mental Status Exam (MMSE) score in subjects with AD and MCI. The study reveals that the elevation of mI/NAA ratio in the hippocampus is more significant than that in the posterior cingulate area, which corresponds to the pathologic procession of AD. The ratios of mI/NAA in the hippocampus and in the posterior cingulate area together provide valuable discrimination among the three groups (AD, MCI, and controls). There is a significant correlation between mI/NAA ratio and cognitive decline.

Transition metal sulfide loaded catalyst

DOEpatents

Maroni, V.A.; Iton, L.E.; Pasterczyk, J.W.; Winterer, M.; Krause, T.R.

1994-04-26

A zeolite-based catalyst is described for activation and conversion of methane. A zeolite support includes a transition metal (Mo, Cr or W) sulfide disposed within the micropores of the zeolite. The catalyst allows activation and conversion of methane to C[sub 2]+ hydrocarbons in a reducing atmosphere, thereby avoiding formation of oxides of carbon.

Golgi-Colonnier method: correlation of the degree of chromium reduction and pH change with quality of staining.

PubMed

Angulo, A; Merchán, J A; Molina, M

1994-03-01

We examined the role of chromium reduction in the Golgi-Colonnier method, correlating the quality of neuronal impregnation with the levels of hexavalent (CrVI) and trivalent (CrIII) chromium in the tissue and in the chromation fluid (CF). The concentrations of both chromium species were assessed by measuring spectrophotometrically the CrVI before and after oxidizing the sample and by calculating the ratio of CrVI to total chromium (chromium ratio, CrR). The CrR was almost identical in the tissue and the CF, decreasing exponentially during chromation due to a progressive consumption of CrVI to form CrIII. Satisfactory cell impregnation was obtained only when the CrR was 0.45-0.7, regardless of other factors. The CrR values could be accurately predicted by the pH increase of the CF; this increase has proven to be a most reliable criterion to decide the endpoint of the chromation process. The dependence of cell staining on the [CrIII], together with the well-known ability of this species to bridge proteins, suggests that the key event for cell impregnation is the cross-linking of neuronal proteins by CrIII polymers.

Reduced N-acetylaspartate levels in the frontal cortex of 3,4-methylenedioxymethamphetamine (Ecstasy) users: preliminary results.

PubMed

Reneman, Liesbeth; Majoie, Charles B L M; Flick, Herman; den Heeten, Gerard J

2002-02-01

The perceived safety of the recreational drug methylenedioxymethamphetamine (MDMA), or Ecstasy, conflicts with animal evidence indicating that MDMA damages cortical serotonin (5-HT) neurons at doses similar to those used by humans. Few data are available about the effects of MDMA on the human brain. This study was designed to evaluate MDMA-related alterations in metabolite ratios with single-voxel proton ((1)H) MR spectroscopy. Fifteen male MDMA users (mean lifetime exposure, 723 tablets; mean time since last tablet, 12.0 weeks) and 12 age-matched control subjects underwent single-voxel (1)H MR spectroscopy. N-Acetylaspartate (NAA)/creatine (Cr), NAA/Choline (Cho), and myoinositol (MI)/Cr ratios were measured in midfrontal gray matter, midoccipital gray matter, and right parietal white matter. Data were analyzed with linear model-based multivariate analysis of variance. NAA/Cr (P =.04) and NAA/Cho (P =.03) ratios, markers associated with neuronal loss or dysfunction, were reduced in the frontal cortex of MDMA users. Neither NAA/Cr (P =.72) nor NAA/Cho (P =.12) ratios were different between both groups in occipital gray matter and parietal white matter (P =.18). Extent of previous MDMA use and frontal cortical NAA/Cr (rho = -.50, P =.012) or NAA/Cho (rho = -.550, P <.01) ratios were significantly associated. Reduced NAA/Cr and NAA/Cho ratios at (1)H MR spectroscopy provide evidence for neuronal abnormality in the frontal cortex of MDMA users; these are correlated with the degree of MDMA exposure. These data suggest that MDMA may be a neurotoxin in humans, as it is in animals.

Calculation reduction method for color digital holography and computer-generated hologram using color space conversion

NASA Astrophysics Data System (ADS)

Shimobaba, Tomoyoshi; Nagahama, Yuki; Kakue, Takashi; Takada, Naoki; Okada, Naohisa; Endo, Yutaka; Hirayama, Ryuji; Hiyama, Daisuke; Ito, Tomoyoshi

2014-02-01

A calculation reduction method for color digital holography (DH) and computer-generated holograms (CGHs) using color space conversion is reported. Color DH and color CGHs are generally calculated on RGB space. We calculate color DH and CGHs in other color spaces for accelerating the calculation (e.g., YCbCr color space). In YCbCr color space, a RGB image or RGB hologram is converted to the luminance component (Y), blue-difference chroma (Cb), and red-difference chroma (Cr) components. In terms of the human eye, although the negligible difference of the luminance component is well recognized, the difference of the other components is not. In this method, the luminance component is normal sampled and the chroma components are down-sampled. The down-sampling allows us to accelerate the calculation of the color DH and CGHs. We compute diffraction calculations from the components, and then we convert the diffracted results in YCbCr color space to RGB color space. The proposed method, which is possible to accelerate the calculations up to a factor of 3 in theory, accelerates the calculation over two times faster than the ones in RGB color space.

Control of Surface Segregation in Bimetallic NiCr Nanoalloys Immersed in Ag Matrix

PubMed Central

Bohra, Murtaza; Singh, Vidyadhar; Grammatikopoulos, Panagiotis; Toulkeridou, Evropi; Diaz, Rosa E.; Bobo, Jean-François; Sowwan, Mukhles

2016-01-01

Cr-surface segregation is a main roadblock encumbering many magneto-biomedical applications of bimetallic M-Cr nanoalloys (where M = Fe, Co and Ni). To overcome this problem, we developed Ni95Cr5:Ag nanocomposite as a model system, consisting of non-interacting Ni95Cr5 nanoalloys (5 ± 1 nm) immersed in non-magnetic Ag matrix by controlled simultaneous co-sputtering of Ni95Cr5 and Ag. We employed Curie temperature (TC) as an indicator of phase purity check of these nanocomposites, which is estimated to be around the bulk Ni95Cr5 value of 320 K. This confirms prevention of Cr-segregation and also entails effective control of surface oxidation. Compared to Cr-segregated Ni95Cr5 nanoalloy films and nanoclusters, we did not observe any unwanted magnetic effects such as presence Cr-antiferromagnetic transition, large non-saturation, exchange bias behavior (if any) or uncompensated higher TC values. These nanocomposites films also lose their unique magnetic properties only at elevated temperatures beyond application requirements (≥800 K), either by showing Ni-type behavior or by a complete conversion into Ni/Cr-oxides in vacuum and air environment, respectively. PMID:26750659

New Recording Layer of Recordable Digital Versatile Disc with CrOx Film Using Red Laser

NASA Astrophysics Data System (ADS)

Liu, Chung Ping; Hung, Yao Ti

2006-03-01

In this study, CrOx film deposited by rf magnetron reactive sputtering was used as a new recording layer for a recordable digital versatile disc (DVD-R) with a red laser. X-ray photoelectron spectroscopy (XPS) indicated the films have three major components: CrO2, CrO3, and Cr2O3. From disc dynamic tests and atomic force microscope (AFM) images of a polycarbonate (PC) substrate, a DVD-R structure of PC/ZnS-SiO2 (30 nm)/CrOx (120 nm)/ZnS-SiO2 (40 nm)/Ag (50 nm), deposited by sputtering at an O2/Ar flow rate ratio of 0.4, had an improved carrier-to-noise ratio (CNR). The principle of recording depends primarily on the explosive pressure of the O2 released due to laser heating of the annealed CrOx film.

Validation of GC-IRMS techniques for δ13C and δ2H CSIA of organophosphorus compounds and their potential for studying the mode of hydrolysis in the environment.

PubMed

Wu, Langping; Kümmel, Steffen; Richnow, Hans H

2017-04-01

Compound-specific stable isotope analysis (CSIA) is among the most promising tools for studying the fate of organic pollutants in the environment. However, the feasibility of multidimensional CSIA was limited by the availability of a robust method for precise isotope analysis of heteroatom-bearing organic compounds. We developed a method for δ 13 C and δ 2 H analysis of eight organophosphorus compounds (OPs) with different chemical properties. In particular, we aimed to compare high-temperature conversion (HTC) and chromium-based HTC (Cr/HTC) units to explore the limitations of hydrogen isotope analysis of heteroatom-bearing compounds. Analysis of the amount dependency of the isotope values (linearity analysis) of OPs indicated that the formation of HCl was a significant isotope fractionation process leading to inaccurate δ 2 H analysis in HTC. In the case of nonchlorinated OPs, by-product formation of HCN, H 2 S, or PH 3 in HTC was observed but did not affect the dynamic range of reproducible isotope values above the limit of detection. No hydrogen-containing by-products were found in the Cr/HTC process by use of ion trap mass spectrometry analysis. The accuracy of gas chromatography - isotope ratio mass spectrometry was validated in comparison with elemental analyzer - isotope ratio mass spectrometry. Dual-isotope fractionation yielded Λ values of 0 ± 0 at pH 7, 7 ± 1 at pH 9, and 30 ± 6 at pH 12, indicating the potential of 2D CSIA to characterize the hydrolysis mechanisms of OPs. This is the first report on the combination of δ 2 H and δ 13 C isotope analysis of OPs, and this is the first study providing a systematic evaluation of HTC and Cr/HTC for hydrogen isotope analysis using OPs as target compounds. Graphical Abstract Comparison of δ 2 H measurement of non-chlorinated and chlorinated OPs via GC-Cr/HTC-IRMS and GC-HTC-IRMS system.

Lime pretreatment of lignocellulosic biomass

NASA Astrophysics Data System (ADS)

Chang, Shushien

Lignocellulose is a valuable alternative energy source. The susceptibility of lignocellulosic biomass to enzymatic hydrolysis is constrained due to its structural features, so pretreatment is essential to enhance enzymatic digestibility. Of the chemicals used as pretreatment agents, it has been reported that alkalis improve biomass digestibility significantly. In comparison with other alkalis such as NaOH and ammonia, lime (calcium hydroxide) has many advantages; it is very inexpensive, is safe, and can be recovered by carbonating wash water. The effects of lime pretreatment were explored on switchgrass and poplar wood, representing herbaceous and woody biomass, respectively. The effects of pretreatment conditions (time, temperature, lime loading, water loading, particle size, and oxygen pressure) have been systematically studies. Lime alone enhances the digestibility of switchgrass significantly; under the recommended conditions, the 3-d total sugar (glucose + xylose) yields of lime-treated switchgrass were 7 times that of untreated sample. When treating poplar wood, lime must be combined with oxygen to achieve high digestibility; oxidative lime pretreatment increased the 3-d total sugar yield of poplar wood to 12 times that of untreated sample. In a fundamental study, to determine why lime pretreatment is effective, the effects of three structural features on enzymatic digestibility were studied: lignin content, acetyl content, and crystallinity index (CrI). Poplar wood was treated with peracetic acid, potassium hydroxide, and ball milling to produce model lignocelluloses with a broad spectrum of lignin contents, acetyl contents, and CrI, respectively. Enzymatic hydrolysis was performed on the model lignocelluloses to determine the digestibility. Correlations between lignin/carbohydrate ratio, acetyl/carbohydrate ratio, CrI and digestibility were developed. The 95% prediction intervals show that the correlations predict the 1-h and 3-d total sugar conversions of a biomass sample within a precision of 5% and 20%, respectively. The digestibility of a variety of lime-treated biomass and ball-milled alpha-cellulose was compared to the correlations determined from the model compounds. The agreement between the measured and predicted values shows that the correlations are satisfactory and the three structural features---lignin content, acetyl content, and CrI---are the major factors that determine enzymatic digestibility.

Correlations between working memory impairment and neurometabolites of prefrontal cortex and lenticular nucleus in patients with major depressive disorder.

PubMed

Shan, Yanyan; Jia, Yanbin; Zhong, Shuming; Li, Xueguo; Zhao, Hui; Chen, Junhao; Lu, Qianyi; Zhang, Lu; Li, Zhinan; Lai, Shunkai; Wang, Ying

2018-02-01

The mechanism of working memory (WM) impairment in MDD remains unclear. We aimed to find out the mechanism by using neuropsychological tests and proton magnetic resonance spectroscopy (1H-MRS). 31 MDD patients and 31 healthy controls were recruited in our study. The WM performance and neurometabolite ratios of prefrontal cortex (PFC) and lenticular nucleus (LN) between two groups were evaluated and compared. And the correlations between abnormal neurometabolite ratios and WM dysfunction were computed. Scores of SDMT, DST(forwards), VRS and 2-back Task(accuracy rate) in MDD were lower than HCs. NAA/Cr ratios of bilateral PFC in MDD were significantly lower than HCs, while no significant differences showed in NAA/Cr ratios of LN and Cho/Cr, mI/Cr values of the bilateral PFC and LN between two groups. And for MDD patients, NAA/Cr ratios in the right PFC were positively correlated with scores of DST (Forwards). Our findings suggest that depressed patients may have impairments in working memory, including phonological loop, visual-spatial sketchpad, episodic buffer and central executive. And the impairment of verbal WM and WM capacity may be associated with the abnormal neurometabolites in the right PFC. Copyright © 2017 Elsevier B.V. All rights reserved.

Cr isotope fractionation factors for Cr(VI) reduction by a metabolically diverse group of bacteria

NASA Astrophysics Data System (ADS)

Basu, Anirban; Johnson, Thomas M.; Sanford, Robert A.

2014-10-01

Reduction of Cr(VI) is an important process that determines the geochemical behavior, mobility and bioavailability of Cr in both terrestrial and marine environments. Many metabolically diverse microorganisms possess Cr(VI) reduction capacity. Cr(VI) reduction fractionates Cr isotopes and thus 53Cr/52Cr ratios can be used to monitor Cr(VI) reduction and redox conditions. The magnitude of isotopic fractionation (ε) for a variety of microbial reduction mechanisms must be known for accurate interpretation of observed shifts in 53Cr/52Cr ratios. We determined isotopic fractionation factors for Cr(VI) reduction by metal reducers Geobacter sulfurreducens and Shewanella sp. strain NR, a denitrifying soil bacterium Pseudomonas stutzeri DCP-Ps1, and a sulfate reducer Desulfovibrio vulgaris. All bacteria investigated in this study produced significant Cr isotope fractionation. The fractionation (ε) for G. sulfurreducens, Shewanella sp. (NR), P. stutzeri DCP-Ps1, and D. vulgaris were -3.03‰ ± 0.12‰, -2.17‰ ± 0.22‰, -3.14‰ ± 0.13‰, and -3.01‰ ± 0.11‰, respectively. Despite differences in microbial strains in this study, the ε did not vary significantly except for Shewanella sp. (NR). Our results suggest that strong isotopic fractionation is induced during Cr(VI) reduction under electron donor poor (∼300 μM) conditions.

Cerebral diffusion tensor imaging and in vivo proton magnetic resonance spectroscopy in patients with fulminant hepatic failure.

PubMed

Saksena, Sona; Rai, Vijan; Saraswat, Vivek Anand; Rathore, Ramkishore Singh; Purwar, Ankur; Kumar, Manoj; Thomas, M Albert; Gupta, Rakesh Kumar

2008-07-01

Cerebral edema is a major complication in patients with fulminant hepatic failure (FHF). The aim of this study was to evaluate the metabolite alterations and cerebral edema in patients with FHF using in vivo proton magnetic resonance spectroscopy (MRS) and diffusion tensor imaging, and to look for its reversibility in survivors. Ten FHF patients along with 10 controls were studied. Five of the 10 patients who recovered had a repeat imaging after three weeks. N-acetylaspartate, choline (Cho), glutamine (Gln), glutamine/glutamate (Glx), and myoinositol ratios were calculated with respect to creatine (Cr). Mean diffusivity (MD) and fractional anisotropy (FA) were calculated in different brain regions. Patients exhibited significantly increased Gln/Cr and Glx/Cr, and reduced Cho/Cr ratios, compared to controls. In the follow-up study, all metabolite ratios were normalized except Glx/Cr. Significantly decreased Cho/Cr were observed in deceased patients compared to controls. In patients, significantly decreased MD and FA values were observed in most topographical locations of the brain compared to controls. MD and FA values showed insignificant increase in the follow-up study compared to their first study. We conclude that the Cho/Cr ratio appears to be an in vivo marker of prognosis in FHF. Decreased MD values suggest predominant cytotoxic edema may be present. Persistence of imaging and MRS abnormalities at three weeks' clinical recovery suggests that metabolic recovery may take longer than clinical recovery in FHF patients.

Immobilization of Cr(VI) and Its Reduction to Cr(III) Phosphate by Granular Biofilms Comprising a Mixture of Microbes

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

Nancharaiah, Y.V.; Francis, A.; Dodge, C.

2010-04-01

We assessed the potential of mixed microbial consortia, in the form of granular biofilms, to reduce chromate and remove it from synthetic minimal medium. In batch experiments, acetate-fed granular biofilms incubated aerobically reduced 0.2 mM Cr(VI) from a minimal medium at 0.15 mM day-1 g-1, with reduction of 0.17 mM day-1 g-1 under anaerobic conditions. There was negligible removal of Cr(VI) (i) without granular biofilms, (ii) with lyophilized granular biofilms, and (iii) with granules in the absence of an electron donor. Analyses by X-ray absorption near edge spectroscopy (XANES) of the granular biofilms revealed the conversion of soluble Cr(VI) tomore » Cr(III). Extended X-ray absorption fine-structure (EXAFS) analysis of the Cr-laden granular biofilms demonstrated similarity to Cr(III) phosphate, indicating that Cr(III) was immobilized with phosphate on the biomass subsequent to microbial reduction. The sustained reduction of Cr(VI) by granular biofilms was confirmed in fed-batch experiments. Our study demonstrates the promise of granular-biofilm-based systems in treating Cr(VI)-containing effluents and wastewater.« less

"A bridge over troubled gaps": up-conversion driven photocatalysis for hydrogen generation and pollutant degradation by near-infrared excitation.

PubMed

Acosta-Mora, P; Domen, K; Hisatomi, T; Lyu, H; Méndez-Ramos, J; Ruiz-Morales, J C; Khaidukov, N M

2018-02-15

Spectral up-conversion (UC) has been attracting growing interest for the effective harvesting of the near-infrared (NIR) part of sunlight for photocatalytic hydrogen production and environmental purification. We present evidence of NIR-to-UV-VIS photon conversion for degradation of organic dyes and hydrogen and oxygen evolution via water-splitting by TiO 2 and Rh-Cr oxide-loaded SrTiO 3 :Al photocatalysts, respectively.

Structure and Mechanical Properties of CrTiAlN/TiAlN Composite Coatings Deposited by Multi-Arc Ion Plating

NASA Astrophysics Data System (ADS)

Yan, Shaojian; Tian, Canxin; Huang, Zhihong; Yang, Bing; Fu, Dejun

2014-10-01

CrTiAlN/TiAlN composite coatings were deposited on cemented carbide by using a home-made industrial scale multi-arc ion plating system. The samples were studied by X-ray diffraction, scanning electron microscopy (SEM), microhardness and ball-on-disk testing. The properties of the CrTiAlN/TiAlN coatings were significantly influenced by the microstructure and the deposition time ratio of TiAlN over CrTiAlN layers. With the increase of deposition time ratio, the microhardness of CrTiAlN/TiAlN increased from 28.6 GPa to 37.5 GPa, much higher than that of CrTiAlN coatings. The friction coefficients of the CrTiAlN/TiAlN coatings were higher than those of CrTiAlN coatings against a cemented carbide ball. The microhardness of the CrTiAlN/TiAlN coatings was changed after annealing at 800°C, and the friction coefficients of the annealed coatings were increased against the cemented carbide ball.

Monitoring interferon β treatment response with magnetic resonance spectroscopy in relapsing remitting multiple sclerosis.

PubMed

Yetkin, Mehmet Fatih; Mirza, Meral; Dönmez, Halil

2016-09-01

The aim of this study is to compare the white matter of multiple sclerosis (MS) patients with healthy controls and to monitor the response to the treatment with magnetic resonance spectroscopy (MRS).Fifteen healthy controls and 36 recently diagnosed MS patients never treated with interferon β were included in this study. In the patient group, MRS was performed before treatment, at 6th and 12th month after the initiation of treatment and once in control group. Patient group was divided into 3 interferon groups randomly. Physical examination findings were recorded as Expanded Disability Status Scale scores before treatment, at 6th and 12th month of interferon treatment.At the end of 1 year follow up, 26 of 36 patients completed the study. In patients' white matter lesions, N-acetylaspartate/creatine (NAA/Cr) ratios were lower than control group's white matters. NAA/Cr ratios were higher in control group's white matter than patient's normal appearing white matter but this difference was not statistically significant. There was no difference in choline/creatine (Cho/Cr) ratios between 2 groups. In follow-up period, NAA/Cr and Cho/Cr ratios obtained from patients' white matter lesions and normal appearing white matter did not change statistically.This study showed that in MS patients' white matters, especially in white matter lesions, neuron viability is reduced compared with healthy controls' normal white matter; and in the patients treated with interferon β NAA/Cr ratios remained stable. These stable levels of metabolite ratios in the patients who received interferon β therapy can be explained with either the shortness of the follow-up period post-treatment or may reflect a positive effect of the beta interferon therapy on the progress of MS.

{sup 53}Mn-{sup 53}Cr CHRONOMETRY OF CB CHONDRITE: EVIDENCE FOR UNIFORM DISTRIBUTION OF {sup 53}Mn IN THE EARLY SOLAR SYSTEM

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

Yamashita, Katsuyuki; Yamakawa, Akane; Nakamura, Eizo

High-precision Cr isotope ratios for chondrules and metal grain separated from CB chondrite Gujba were determined. The {epsilon}{sup 54}Cr values ({epsilon}{sup i}Cr = [({sup i}Cr/{sup 52}Cr){sub sample}/({sup i}Cr/{sup 52}Cr){sub standard} - 1] x 10{sup 4}) for all samples were identical within the analytical uncertainty, with a mean value of +1.29 {+-} 0.02. Uniform {epsilon}{sup 54}Cr signatures of both chondrules and metal grains imply that the Cr isotope systematics of the meteorite was once completely equilibrated. The {epsilon}{sup 53}Cr values of the chondrules and metal grain, on the other hand, display a strong correlation with the {sup 55}Mn/{sup 52}Cr ratio. Themore » {sup 53}Mn/{sup 55}Mn calculated from the slope of the isochron is (3.18 {+-} 0.52) x 10{sup -6}. This corresponds to absolute ages of 4563.7 {+-} 1.2 Ma and 4563.5 {+-} 1.1 Ma using angrites D'Orbigny and LEW 86010, respectively, as time anchors. These ages are consistent with the ages obtained using other short- and long-lived radio nuclides, supporting the uniform distribution of {sup 53}Mn in the early solar nebula.« less

Brain metabolites in autonomic regulatory insular sites in heart failure.

PubMed

Woo, Mary A; Yadav, Santosh K; Macey, Paul M; Fonarow, Gregg C; Harper, Ronald M; Kumar, Rajesh

2014-11-15

Autonomic, pain, and neuropsychologic comorbidities appear in heart failure (HF), likely resulting from brain changes, indicated as loss of structural integrity and functional deficits. Among affected brain sites, the anterior insulae are prominent in serving major regulatory roles in many of the disrupted functions commonly seen in HF. Metabolite levels, including N-acetylaspartate (NAA), creatine (Cr), choline (Cho), and myo-inositol (MI), could indicate the nature of anterior insula tissue injury in HF. The study aim was to assess anterior insular metabolites to determine processes mediating autonomic, pain, and neuropsychologic disruptions in HF. We performed magnetic resonance spectroscopy in bilateral anterior insulae in 11 HF and 53 controls, using a 3.0-Tesla magnetic resonance imaging scanner. Peaks for NAA at 2.02 ppm, Cr at 3.02 ppm, Cho at 3.2 ppm, and MI at 3.56 ppm were assigned, peak areas were calculated, and metabolites were expressed as ratios, including NAA/Cr, Cho/Cr, and MI/Cr. HF patients showed significantly increased Cho/Cr ratios, indicative of glial proliferation or injury, on the left anterior insula, and reduced NAA/Cr levels, suggesting neuronal loss/dysfunction, on the right anterior insula over controls. No differences in MI/Cr ratios appeared between groups. Right anterior insular neuronal loss and left glial alterations may contribute to distorted autonomic, pain, and neuropsychologic functions found in HF. Copyright © 2014 Elsevier B.V. All rights reserved.

Brain Metabolites in Autonomic Regulatory Insular Sites in Heart Failure

PubMed Central

Woo, Mary A.; Yadav, Santosh K.; Macey, Paul M.; Fonarow, Gregg C.; Harper, Ronald M.; Kumar, Rajesh

2014-01-01

Autonomic, pain, and neuropsychologic comorbidities appear in heart failure (HF), likely resulting from brain changes, indicated as loss of structural integrity and functional deficits. Among affected brain sites, the anterior insulae are prominent in serving major regulatory roles in many of the disrupted functions commonly seen in HF. Metabolite levels, including N-acetylaspartate (NAA), creatine (Cr), choline (Cho), and myo-inositol (MI), could indicate the nature of anterior insula tissue injury in HF. The study aim was to assess anterior insular metabolites to determine processes mediating autonomic, pain, and neuropsychologic disruptions in HF. We performed magnetic resonance spectroscopy in bilateral anterior insulae in 11 HF and 53 controls, using a 3.0-Tesla magnetic resonance imaging scanner. Peaks for NAA at 2.02ppm, Cr at 3.02ppm, Cho at 3.2ppm, and MI at 3.56ppm were assigned, peak areas calculated, and metabolites expressed as ratios, including NAA/Cr, Cho/Cr, and MI/Cr. HF patients showed significantly increased Cho/Cr ratios, indicative of glial proliferation or injury, on the left anterior insula, and reduced NAA/Cr levels, suggesting neuronal loss/dysfunction, on the right anterior insula over controls. No differences in MI/Cr ratios appeared between groups. Right anterior insular neuronal loss and left glial alterations may contribute to distorted autonomic, pain, and neuropsychologic functions found in HF. PMID:25248953

Catalytic conversion of cellulose to levulinic acid by metal chlorides.

PubMed

Peng, Lincai; Lin, Lu; Zhang, Junhua; Zhuang, Junping; Zhang, Beixiao; Gong, Yan

2010-08-02

The catalytic performance of various metal chlorides in the conversion of cellulose to levulinic acid in liquid water at high temperatures was investigated. The effects of reaction parameters on the yield of levulinic acid were also explored. The results showed that alkali and alkaline earth metal chlorides were not effective in conversion of cellulose, while transition metal chlorides, especially CrCl(3), FeCl(3) and CuCl(2) and a group IIIA metal chloride (AlCl(3)), exhibited high catalytic activity. The catalytic performance was correlated with the acidity of the reaction system due to the addition of the metal chlorides, but more dependent on the type of metal chloride. Among those metal chlorides, chromium chloride was found to be exceptionally effective for the conversion of cellulose to levulinic acid, affording an optimum yield of 67 mol % after a reaction time of 180 min, at 200 degrees C, with a catalyst dosage of 0.02 M and substrate concentration of 50 wt %. Chromium metal, most of which was present in its oxide form in the solid sample and only a small part in solution as Cr3+ ion, can be easily separated from the resulting product mixture and recycled. Finally, a plausible reaction scheme for the chromium chloride catalyzed conversion of cellulose in water was proposed.

Design and aero-acoustic analysis of a counter-rotating wind turbine

NASA Astrophysics Data System (ADS)

Agrawal, Vineesh V.

Wind turbines have become an integral part of the energy business because they are one of the most economical and reliable sources of renewable energy. Conventional wind turbines are capable of capturing less than half of the energy present in the wind. Hence, to make the wind turbines more efficient, it is important to increase their performance. A horizontal axis wind turbine with multiple rotors is one concept that can achieve a higher power conversion rate. Also, a concern for wind energy is the noise generated by wind turbines. Hence, an investigation into the acoustic behavior of a multi-rotor horizontal axis wind turbine is required. In response to the need of a wind turbine design with higher power coefficient, a unique design of a counter-rotating horizontal axis wind turbine (CR-HAWT) is proposed. The Blade Element Momentum (BEM) theory is used to aerodynamically design the blades of the two rotors. Modifications are made to the BEM theory to accommodate the interaction of the two rotors. The tower effect on the noise generation of the downwind rotor is investigated. Predictions are made for the total noise generated by the wind turbine at its design operating conditions. A total power coefficient of 65.2% is predicted for the proposed CR-HAWT design. A low tip speed ratio is chosen to minimize the noise generation. The aeroacoustic analysis of the CR-HAWT shows that the noise generated at its design operating conditions is within an acceptable range. Thus, the CR-HAWT is predicted to be a quiet wind turbine with a high power coefficient, making it highly desirable for small wind turbine applications.

[Clinical application of proton magnetic resonance spectroscopy in children with idiopathic epilepsy].

PubMed

Shao, Xiao-Li; Zhou, Zhong-Shu; Hong, Wen

2010-06-01

This study examined the biochemical metabolism by proton magnetic resonance spectroscopy ('H-MRS) in order to explore the value of 'H-MRS in idiopathic epilepsy in children. Thirty-three children with idiopathic epilepsy (14 cases with history of febrile seizures and 19 cases without) and six normal controls experienced MRI of the skull and brain and single-voxel 'H-MRS examinations of the hippocampi-temporal lobe. The signal intensities of N-acetylaspartate (NAA), eatine+phosphocreatine (Cr), choline-containing compounds (Cho) and lactate (Lac) and the ratios of NAA/ (Cho+Cr) and Lac/Cr were compared between the patients and normal controls. MRI examination showed that only one child with epilepsy had myelin dysplasia. 'H-MRS examination showed that the ratio of NAA/ (Cho+Cr) in the epilepsy group was lower than that in the control group (0.64+/-0.07 vs 0.73+/-0.05; P<0.01). The epileptic children with history of febrile seizures had a more decreased ratio of NAA/ (Cho+Cr) compared with those without the history (0.61+/-0.07 vs 0.66+/-0.06; P<0.05). There were no significant differences in the ratio of Lac/Cr between the epilepsy and the control groups. 'H-MRS may provide early information on brain injury sensitively and non-invasively in children with epilepsy. It may be used for diagnosis and prognosis evaluation of epilepsy.

Effect of load ratio and saltwater corrosive environment on the initiation life of fatigue of 10Ni5CrMoV steel

NASA Astrophysics Data System (ADS)

Xie, Xing; Yi, Hong; Xu, Jian; Gen, Liming; Chen, Luyun

2017-09-01

Fatigue initiation life has been studied with 10CrNi5MoV steel for use in ocean engineering at different load ratios and in different environmental media. The microstructure and micro-topography have been observed and analyzed by means of SEM, EDS and EBSD. Our findings indicate that, the initiation life of 10Ni5CrMoV steel in seawater is shorter than that in air, and the difference in longevity is larger with the increasing of load ratio. Corrosion pits had a great influence on initial corrosion fatigue life.

Parkinson's disease: in vivo metabolic changes in the frontal and parietal cortices in 6-OHDA treated rats during different periods.

PubMed

Hou, Zhongyu; Zhang, Zhonghe; Meng, Haiwei; Lin, Xiangtao; Sun, Bo; Lei, Hao; Fang, Ke; Fang, Fang; Liu, Maili; Liu, Shuwei

2014-02-01

This study aims to investigate metabolic changes in frontal and parietal cortices in the 6-OHDA induced Parkinson's rats. Ratios of N-acetyl-aspartic acid/creatine (NAA/Cr), choline/creatine (Cho/Cr), and glumatic acid and glutamine glutaminic acid/creatine (Glx/Cr) of regions of interests (ROIs) in the frontal and parietal cortices, and the substantia nigra were analyzed. NAA/Cr, Cho/Cr and Glx/Cr in the frontal and parietal cortices in the lesion side did not show any significant differences two weeks after operation compared with the contralateral side (p > 0.05). NAA/Cr in the frontal cortex in the lesion side was significantly lower in the five weeks after operation; Cho/Cr remained normal; Glx/Cr increased (p < 0.05), and all ratios of parietal cortex were normal. In the eight weeks after operation, NAA/Cr in the frontal cortex in the lesion side was lower than that of the five weeks (p < 0.01), Cho/Cr still remained normal while Glx/Cr was higher than before (p < 0.01). Regarding the parietal cortex, NAA/Cr increased significantly, while Cho/Cr and Glx/Cr remained normal. In the 12 weeks after operation, NAA/Cr, Cho/Cr and Glx/Cr in frontal cortex were consistent with that of the eight weeks, while they remained at the normal level in parietal cortex. The NAA/Cr in the substantia nigra decreased and Cho/Cr increased significantly during 2-8 weeks, and remained at the same level during 8-12 weeks. There are metabolic disturbances in PD rats. The transient hyperfunction in the parietal cortex can be considered as a compensation for the dysfunction of the frontal cortex and substantia nigra.

Urinary Uric Acid/Creatinine Ratio - A Marker For Perinatal Asphyxia.

PubMed

Patel, Kinjal Prahaladbhai; Makadia, Mayur Goradhanbhai; Patel, Vishwal Indravardan; Nilayangode, Haridas Neelakandan; Nimbalkar, Somashekhar Marutirao

2017-01-01

Perinatal hypoxia is one of the leading causes of perinatal mortality in developing countries. Both apgar score and arterial blood pH predict the neonatal mortality in asphyxia. Apgar score alone does not predict neurologic outcome and as it is influenced by various factors. This study was conducted to evaluate the utility and sensitivity of urinary uric acid to creatinine ratio (UA/Cr ratio) in asphyxia diagnosis, compared to invasive Arterial Blood Gas (ABG) analysis. To assess the urinary uric acid/creatinine ratio as an additional marker for perinatal asphyxia compared with ABG analysis in apgar score monitoring. The present case control study was conducted at a teaching hospital in Central Gujarat. Data of 40 healthy newborns and 40 asphyxiated newborns were collected. In absence of regional estimates, a sample of size 39 was required to attain a power of 80% at 5% alpha (type I error) considering a moderate effect size of 0.65. (UA/Cr) ratio was measured from the spot urine sample collected during 24-72 hours of birth. Statistical analysis was performed by Independent t-test, Pearson's correlation coefficient (r) and Receiver Operating Characteristic (ROC) plots. The mean (UA/Cr ratio) (2.75±0.18 vs 1.78±0.23) is significantly higher in asphyxiated group than in the control group (p<0.0001). Urinary UA/Cr ratio had negative correlation with blood pH (r= -0.27, p=0.18), which was not significant (p>0.05). Urinary UA/Cr ratio with criterion of >2.3 had 100% sensitivity, 100% specificity with AUC of 1 (p<0.0001) had a better predictive value. Apgar score is usually reduced in neonates with congenital anomalies and premature neonates. Hence, it is preferable that the clinical diagnosis of asphyxia by apgar scores be supported by other investigations so that early decision can be taken about the level of care the baby needs. pH, lactates and base deficits change with establishment of respiration following resuscitation. However, pH, lactate, base deficit estimations are invasive and need rapid estimations. Non-invasive urinary UA/Cr ratio may be an answer to these issues as it easy, economical and equally efficient.

The predictive value of baseline NAA/Cr for treatment response of first-episode schizophrenia: A ¹H MRS study.

PubMed

Liu, Weibo; Yu, Hualiang; Jiang, Biao; Pan, Bing; Yu, Shaohua; Li, Huichun; Zheng, Leilei

2015-07-23

The study focused on the predictive value of baseline metabolite ratios in bilateral hippocampus of first-episode schizophrenia by using proton magnetic resonance spectroscopy ((1)H MRS). (1)H MRS data were acquired from 23 hallucination and 17 non-hallucination first-episode schizophrenia patients compared with 17 healthy participants. Clinical characteristics of patients were rated using the Positive and Negative Syndrome Scale (PANSS) before and after 3-month treatment. The schizophrenia patients showed lower NAA/Cr ratio than healthy participants respectively (p=0.024; p=0.001), and non-hallucination patients had even lower NAA/Cr ratio than hallucination patients (p=0.033). After 3-month treatment, hallucination patients had greater improvement in negative symptoms than non-hallucination patients (p=0.018). The reduction of PANSS total score and negative factor score was positively correlated with the left NAA/Cr in both group patients (p<0.05). Given that the bilateral hippocampal baseline NAA/Cr had predictive value for the whole treatment response, and the left hippocampal NAA/Cr can predict the prognosis of negative symptoms during acute phase medication in first-episode schizophrenia. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Pathologic Complete Response Predicts Recurrence-Free Survival More Effectively by Cancer Subset: Results From the I-SPY 1 TRIAL—CALGB 150007/150012, ACRIN 6657

PubMed Central

Esserman, Laura J.; Berry, Donald A.; DeMichele, Angela; Carey, Lisa; Davis, Sarah E.; Buxton, Meredith; Hudis, Cliff; Gray, Joe W.; Perou, Charles; Yau, Christina; Livasy, Chad; Krontiras, Helen; Montgomery, Leslie; Tripathy, Debasish; Lehman, Constance; Liu, Minetta C.; Olopade, Olufunmilayo I.; Rugo, Hope S.; Carpenter, John T.; Dressler, Lynn; Chhieng, David; Singh, Baljit; Mies, Carolyn; Rabban, Joseph; Chen, Yunn-Yi; Giri, Dilip; van 't Veer, Laura; Hylton, Nola

2012-01-01

Purpose Neoadjuvant chemotherapy for breast cancer provides critical information about tumor response; how best to leverage this for predicting recurrence-free survival (RFS) is not established. The I-SPY 1 TRIAL (Investigation of Serial Studies to Predict Your Therapeutic Response With Imaging and Molecular Analysis) was a multicenter breast cancer study integrating clinical, imaging, and genomic data to evaluate pathologic response, RFS, and their relationship and predictability based on tumor biomarkers. Patients and Methods Eligible patients had tumors ≥ 3 cm and received neoadjuvant chemotherapy. We determined associations between pathologic complete response (pCR; defined as the absence of invasive cancer in breast and nodes) and RFS, overall and within receptor subsets. Results In 221 evaluable patients (median tumor size, 6.0 cm; median age, 49 years; 91% classified as poor risk on the basis of the 70-gene prognosis profile), 41% were hormone receptor (HR) negative, and 31% were human epidermal growth factor receptor 2 (HER2) positive. For 190 patients treated without neoadjuvant trastuzumab, pCR was highest for HR-negative/HER2-positive patients (45%) and lowest for HR-positive/HER2-negative patients (9%). Achieving pCR predicted favorable RFS. For 172 patients treated without trastuzumab, the hazard ratio for RFS of pCR versus no pCR was 0.29 (95% CI, 0.07 to 0.82). pCR was more predictive of RFS by multivariate analysis when subtype was taken into account, and point estimates of hazard ratios within the HR-positive/HER2-negative (hazard ratio, 0.00; 95% CI, 0.00 to 0.93), HR-negative/HER2-negative (hazard ratio, 0.25; 95% CI, 0.04 to 0.97), and HER2-positive (hazard ratio, 0.14; 95% CI, 0.01 to 1.0) subtypes are lower. Ki67 further improved the prediction of pCR within subsets. Conclusion In this biologically high-risk group, pCR differs by receptor subset. pCR is more highly predictive of RFS within every established receptor subset than overall, demonstrating that the extent of outcome advantage conferred by pCR is specific to tumor biology. PMID:22649152

Brain metabolic correlates of decision making in amnestic mild cognitive impairment.

PubMed

Griffith, H Randall; Okonkwo, Ozioma C; den Hollander, Jan A; Belue, Katherine; Copeland, Jacqueline; Harrell, Lindy E; Brockington, John C; Clark, David G; Marson, Daniel C

2010-01-01

Persons with amnestic mild cognitive impairment (MCI) have subtle impairments in medical decision-making capacity (MDC). We examined the relationship between proton magnetic resonance spectroscopy (MRS) and MDC in MCI. Twenty-nine MCI patients and 42 controls underwent MRS to obtain ratios of N-acetylaspartate (NAA)/Creatine (Cr), Choline (Cho)/Cr, and myo-Inositol (mI)/Cr of the posterior cingulate. They also completed the Capacity to Consent to Treatment Instrument (CCTI), a vignette-based instrument measuring decisional standards of expressing choice, appreciating consequences of choice, providing rational reasons for choice, and understanding treatment choices. Patients showed abnormal MRS ratios of mI/Cr and Cho/Cr compared to controls, and impairments on the CCTI understanding and reasoning Standards. Performance on the reasoning standard of the CCTI was correlated with NAA/Cr (r = .46, p < .05). The relationship of NAA/Cr with decision-making suggests a role for posterior cortical neuronal functioning in performance of complex IADLs in MCI.

Social Impairment in the "Care in the Community" Cohort: The Effect of Deinstitutionalization and Changes over Time in the Community.

ERIC Educational Resources Information Center

Beadle-Brown, Julie; Forrester-Jones, Rachel

2003-01-01

A longitudinal study involving 250 adults who had been institutionalized found that once they moved into the community, social impairment did not change over time, although there was a significant decrease in conversation and social mixing, non-verbal communication, and initiation of conversation and social interaction. (Contains references.) (CR)

Characterization of emission factors related to source activity for trichloroethylene degreasing and chrome plating processes.

PubMed

Wadden, R A; Hawkins, J L; Scheff, P A; Franke, J E

1991-09-01

A study at an automotive parts fabrication plant evaluated four metal surface treatment processes during production conditions. The evaluation provides examples of how to estimate process emission factors from activity and air concentration data. The processes were open tank and enclosed tank degreasing with trichloroethylene (TCE), chromium conversion coating, and chromium electroplating. Area concentrations of TCE and chromium (Cr) were monitored for 1-hr periods at three distances from each process. Source activities at each process were recorded during each sampling interval. Emission rates were determined by applying appropriate mass balance models to the concentration patterns around each source. The emission factors obtained from regression analysis of the emission rate and activity data were 16.9 g TCE/basket of parts for the open-top degreaser; 1.0 g TCE/1000 parts for the enclosed degreaser; 1.48-1.64 mg Cr/1000 parts processed in the hot CrO3/HNO3 tank for the chrome conversion coating; and 5.35-9.17 mg Cr/rack of parts for chrome electroplating. The factors were also used to determine the efficiency of collection for the local exhaust systems serving each process. Although the number of observations were limited, these factors may be useful for providing initial estimates of emissions from similar processes in other settings.

X-ray fluorescence analysis of Cr(6+) component in mixtures of Cr(2)O(3) and K(2)CrO(4).

PubMed

Tochio, Tatsunori; Sakakura, Shusuke; Oohashi, Hirofumi; Mizota, Hirohisa; Zou, Yanhui; Ito, Yoshiaki; Fukushima, Sei; Tanuma, Shigeo; Shoji, Takashi; Fujimura, Hajime; Yamashita, Michiru

2010-01-01

X-ray fluorescence analysis using Cr K(alpha) spectra was applied to the determination of the mixing ratio of Cr(6+) to (Cr(6+) + Cr(3+)) in several mixtures of K(2)CrO(4) and Cr(2)O(3). Because the powder of K(2)CrO(4) contained large particles that were more than 50 microm in diameter, it was ground between a pestle and a mortar for about 8 h. The coarse particles still remaining were removed by using a sieve with 325-mesh (44 microm) in order to reduce the difference in absorption effects between emissions from Cr(6+) and those from Cr(3+). The mixing ratio, K(2)CrO(4)/(K(2)CrO(4) + Cr(2)O(3)), of the five mixtures investigated is 0.50, 0.40, 0.20, 0.10, and 0.05 in weight, respectively. Each spectrum obtained was analyzed by decomposing it into two reference spectra, those of the two pure materials, K(2)CrO(4) and Cr(2)O(3), with a constant background. The results for the mixtures containing K(2)CrO(4) of more than 20 wt% are that the relative deviation from the true value is less than approximately 5%. On the other hand, when the content of K(2)CrO(4) decreases to less than 10 wt%, the relative deviation gets so large as 20 - 25%. The error coming from a peak separation of spectrum involved in our results were estimated by applying our method to five sets of data for each mixture computationally generated, taking into account the uncertainty in total counts of real measurements.

Heterogeneous Distribution of Chromium on Mercury

NASA Astrophysics Data System (ADS)

Nittler, L. R.; Boujibar, A.; Crapster-Pregont, E.; Frank, E. A.; McCoy, T. J.; McCubbin, F. M.; Starr, R. D.; Vander Kaaden, K. E.; Vorburger, A.; Weider, S. Z.

2018-05-01

Mercury's surface has an average Cr/Si ratio of 0.003 (Cr 800 ppm), with at least a factor of 2 systematic uncertainty. Cr is heterogeneously distributed and correlated with Mg, Ca, S, and Fe and anti-correlated with Al.

THE B/C AND SUB-IRON/IRON COSMIC RAY RATIOS—FURTHER EVIDENCE IN FAVOR OF THE SPIRAL-ARM DIFFUSION MODEL

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

Benyamin, David; Piran, Tsvi; Shaviv, Nir J.

The boron to carbon (B/C) and sub-Fe/Fe ratios provide an important clue on cosmic ray (CR) propagation within the Galaxy. These ratios estimate the grammage that the CRs traverse as they propagate from their sources to Earth. Attempts to explain these ratios within the standard CR propagation models require ad hoc modifications and even with those these models necessitate inconsistent grammages to explain both ratios. As an alternative, physically motivated model, we have proposed that CRs originate preferably within the galactic spiral arms. CR propagation from dynamic spiral arms has important imprints on various secondary to primary ratios, such asmore » the B/C ratio and the positron fraction. We use our spiral-arm diffusion model with the spallation network extended up to nickel to calculate the sub-Fe/Fe ratio. We show that without any additional parameters the spiral-arm model consistently explains both ratios with the same grammage, providing further evidence in favor of this model.« less

Sustained Recycle in Light Water and Sodium-Cooled Reactors

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

Steven J. Piet; Samuel E. Bays; Michael A. Pope

2010-11-01

From a physics standpoint, it is feasible to sustain recycle of used fuel in either thermal or fast reactors. This paper examines multi-recycle potential performance by considering three recycling approaches and calculating several fuel cycle parameters, including heat, gamma, and neutron emission of fresh fuel; radiotoxicity of waste; and uranium utilization. The first recycle approach is homogeneous mixed oxide (MOX) fuel assemblies in a light water reactor (LWR). The transuranic portion of the MOX was varied among Pu, NpPu, NpPuAm, or all-TRU. (All-TRU means all isotopes through Cf-252.) The Pu case was allowed to go to 10% Pu in freshmore » fuel, but when the minor actinides were included, the transuranic enrichment was kept below 8% to satisfy the expected void reactivity constraint. The uranium portion of the MOX was enriched uranium. That enrichment was increased (to as much as 6.5%) to keep the fuel critical for a typical LWR irradiation. The second approach uses heterogeneous inert matrix fuel (IMF) assemblies in an LWR - a mix of IMF and traditional UOX pins. The uranium-free IMF fuel pins were Pu, NpPu, NpPuAm, or all-TRU. The UOX pins were limited to 4.95% U-235 enrichment. The number of IMF pins was set so that the amount of TRU in discharged fuel from recycle N (from both IMF and UOX pins) was made into the new IMF pins for recycle N+1. Up to 60 of the 264 pins in a fuel assembly were IMF. The assembly-average TRU content was 1-6%. The third approach uses fast reactor oxide fuel in a sodium-cooled fast reactor with transuranic conversion ratio of 0.50 and 1.00. The transuranic conversion ratio is the production of transuranics divided by destruction of transuranics. The FR at CR=0.50 is similar to the CR for the MOX case. The fast reactor cases had a transuranic content of 33-38%, higher than IMF or MOX.« less

A revision in hydrogen isotopic composition of USGS42 and USGS43 human-hair stable isotopic reference materials for forensic science

USGS Publications Warehouse

Coplen, Tyler B.; Qi, Haiping

2016-01-01

The hydrogen isotopic composition (δ2HVSMOW-SLAP) of USGS42 and USGS43 human hair stable isotopic reference materials, normalized to the VSMOW (Vienna-Standard Mean Ocean Water)–SLAP (Standard Light Antarctic Precipitation) scale, was originally determined with a high temperature conversion technique using an elemental analyzer (TC/EA) with a glassy carbon tube and glassy carbon filling and analysis by isotope-ratio mass spectrometer (IRMS). However, the TC/EA IRMS method can produce inaccurate δ2HVSMOW-SLAPresults when analyzing nitrogen-bearing organic substances owing to the formation of hydrogen cyanide (HCN), leading to non-quantitative conversion of a sample into molecular hydrogen (H2) for IRMS analysis. A single-oven, chromium-filled, elemental analyzer (Cr-EA) coupled to an IRMS substantially improves the measurement quality and reliability of hydrogen isotopic analysis of hydrogen- and nitrogen-bearing organic material because hot chromium scavenges all reactive elements except hydrogen. USGS42 and USGS43 human hair isotopic reference materials have been analyzed with the Cr-EA IRMS method, and the δ2HVSMOW-SLAP values of their non-exchangeable hydrogen fractions have been revised:where mUr = 0.001 = ‰. On average, these revised δ2HVSMOW-SLAP values are 5.7 mUr more positive than those previously measured. It is critical that readers pay attention to the δ2HVSMOW-SLAP of isotopic reference materials in publications as they may need to adjust the δ2HVSMOW–SLAP measurement results of human hair in previous publications to ensure all results are on the same isotope-delta scale.

A revision in hydrogen isotopic composition of USGS42 and USGS43 human-hair stable isotopic reference materials for forensic science.

PubMed

Coplen, Tyler B; Qi, Haiping

2016-09-01

The hydrogen isotopic composition (δ(2)HVSMOW-SLAP) of USGS42 and USGS43 human hair stable isotopic reference materials, normalized to the VSMOW (Vienna-Standard Mean Ocean Water)-SLAP (Standard Light Antarctic Precipitation) scale, was originally determined with a high temperature conversion technique using an elemental analyzer (TC/EA) with a glassy carbon tube and glassy carbon filling and analysis by isotope-ratio mass spectrometer (IRMS). However, the TC/EA IRMS method can produce inaccurate δ(2)HVSMOW-SLAP results when analyzing nitrogen-bearing organic substances owing to the formation of hydrogen cyanide (HCN), leading to non-quantitative conversion of a sample into molecular hydrogen (H2) for IRMS analysis. A single-oven, chromium-filled, elemental analyzer (Cr-EA) coupled to an IRMS substantially improves the measurement quality and reliability of hydrogen isotopic analysis of hydrogen- and nitrogen-bearing organic material because hot chromium scavenges all reactive elements except hydrogen. USGS42 and USGS43 human hair isotopic reference materials have been analyzed with the Cr-EA IRMS method, and the δ(2)HVSMOW-SLAP values of their non-exchangeable hydrogen fractions have been revised: [Formula: see text] [Formula: see text] where mUr=0.001=‰. On average, these revised δ(2)HVSMOW-SLAP values are 5.7mUr more positive than those previously measured. It is critical that readers pay attention to the δ(2)HVSMOW-SLAP of isotopic reference materials in publications as they may need to adjust the δ(2)HVSMOW-SLAP measurement results of human hair in previous publications to ensure all results are on the same isotope-delta scale. Published by Elsevier Ireland Ltd.

Prognostic value of high-field proton magnetic resonance spectroscopy in patients presenting with clinically isolated syndromes suggestive of multiple sclerosis.

PubMed

Wattjes, Mike P; Harzheim, Michael; Lutterbey, Götz G; Bogdanow, Manuela; Schmidt, Stephan; Schild, Hans H; Träber, Frank

2008-02-01

The aim of this study was to determine the prognostic value of metabolic alterations in the normal-appearing white matter (NAWM) of patients presenting with clinically isolated syndromes (CIS) suggestive of multiple sclerosis (MS) with special regard to the prediction of conversion to definite MS. Using a 3T whole-body MR system, a multisequence conventional MRI protocol and single-voxel proton MR spectroscopy (PRESS, repetition time 2000 ms, echo times 38 ms and 140 ms) of the parietal NAWM were performed in 25 patients presenting with CIS at baseline and in 20 controls. Absolute concentrations of N-acetyl-aspartate (tNAA), myo-inositol (Ins), choline (Cho) and creatine (tCr) as well as metabolite ratios were determined. Follow-up including neurological assessment and conventional MRI was performed 3-4 and 6-7 months after the initial event. Nine patients converted to definite MS during the follow-up period. Compared to controls, those patients who converted to MS also showed significantly lower tNAA concentrations in the NAWM (-13.4%, P = 0.002) whereas nonconverters (-6.5%, P = 0.052) did not. The Ins concentration was 20.2% higher in the converter group and 1.9% higher in the nonconverter group, but these differences did not reach significance. No significant differences could be observed for tCr and Cho in either patient group. Axonal damage at baseline in patients presenting with CIS was more prominent in those who subsequently converted to definite MS in the short term follow-up, indicating that tNAA might be a sufficient prognostic marker for patients with a higher risk of conversion to early definite MS.

Imaging increased glutamate in children with Sturge-Weber syndrome: Association with epilepsy severity.

PubMed

Juhász, Csaba; Hu, Jiani; Xuan, Yang; Chugani, Harry T

2016-05-01

Sturge-Weber syndrome (SWS) is strongly associated with epilepsy. Brain tissue studies have suggested that epileptic activity in SWS is driven by glutamatergic synaptic activity. Here, we used proton magnetic resonance spectroscopic imaging (MRSI) to test if glutamate (GLU) concentrations are increased in the affected hemisphere and if such increases are associated with severity of epilepsy in children with SWS. We also studied the metabolic correlates of MRSI abnormalities, using glucose positron emission tomography (PET) imaging. 3T MRI and glucose PET were performed in 10 children (age: 7-78 months) with unilateral SWS and a history of epilepsy. MRSI data were acquired from the affected (ipsilateral) and non-affected (contralateral) hemispheres. GLU, N-acetyl-aspartate (NAA) and creatine (Cr) were quantified in multiple voxels; GLU/Cr and NAA/Cr ratios were calculated and compared to seizure frequency as well as glucose PET findings. The highest GLU/Cr ratios were found in the affected hemisphere in all children except one with severe atrophy. The maximum ipsilateral/contralateral GLU/Cr ratios ranged between 1.0 and 2.5 (mean: 1.6). Mean ipsilateral/contralateral GLU/Cr ratios were highest in the youngest children and showed a strong positive correlation with clinical seizure frequency scores assessed at the time of the scan (r=0.88, p=0.001) and also at follow-up (up to 1 year, r=0.80, p=0.009). GLU increases in the affected hemisphere coincided with areas showing current or previous increases of glucose metabolism on PET in 5 children. NAA/Cr ratios showed no association with clinical seizure frequency. Increased glutamate concentrations in the affected hemisphere, measured by MRSI, are common in young children with unilateral SWS and are associated with frequent seizures. The findings lend support to the role of excess glutamate in SWS-associated epilepsy. Copyright © 2016 Elsevier B.V. All rights reserved.

Spectral dependence of backscattering coefficient of mixed phase clouds over West Africa measured with two-wavelength Raman polarization lidar: Features attributed to ice-crystals corner reflection

NASA Astrophysics Data System (ADS)

Veselovskii, I.; Goloub, P.; Podvin, T.; Tanre, D.; Ansmann, A.; Korenskiy, M.; Borovoi, A.; Hu, Q.; Whiteman, D. N.

2017-11-01

The existing models predict that corner reflection (CR) of laser radiation by simple ice crystals of perfect shape, such as hexagonal columns or plates, can provide a significant contribution to the ice cloud backscattering. However in real clouds the CR effect may be suppressed due to crystal deformation and surface roughness. In contrast to the extinction coefficient, which is spectrally independent, consideration of diffraction associated with CR results in a spectral dependence of the backscattering coefficient. Thus measuring the spectral dependence of the cloud backscattering coefficient, the contribution of CR can be identified. The paper presents the results of profiling of backscattering coefficient (β) and particle depolarization ratio (δ) of ice and mixed-phase clouds over West Africa by means of a two-wavelength polarization Mie-Raman lidar operated at 355 nm and 532 nm during the SHADOW field campaign. The lidar observations were performed at a slant angle of 43 degree off zenith, thus CR from both randomly oriented crystals and oriented plates could be analyzed. For the most of the observations the cloud backscatter color ratio β355/β532 was close to 1.0, and no spectral features that might indicate the presence of CR of randomly oriented crystals were revealed. Still, in two measurement sessions we observed an increase of backscatter color ratio to a value of nearly 1.3 simultaneously with a decrease of the spectral depolarization ratio δ355/δ532 ratio from 1.0 to 0.8 inside the layers containing precipitating ice crystals. We attribute these changes in optical properties to corner reflections by horizontally oriented ice plates.

On-line hydrogen-isotope measurements of organic samples using elemental chromium: An extension for high temperature elemental-analyzer techniques

USGS Publications Warehouse

Gehre, Matthias; Renpenning, Julian; Gilevska, Tetyana; Qi, Haiping; Coplen, Tyler B.; Meijer, Harro A.J.; Brand, Willi A.; Schimmelmann, Arndt

2015-01-01

The high temperature conversion (HTC) technique using an elemental analyzer with a glassy carbon tube and filling (temperature conversion/elemental analysis, TC/EA) is a widely used method for hydrogen isotopic analysis of water and many solid and liquid organic samples with analysis by isotope-ratio mass spectrometry (IRMS). However, the TC/EA IRMS method may produce inaccurate δ2H results, with values deviating by more than 20 mUr (milliurey = 0.001 = 1‰) from the true value for some materials. We show that a single-oven, chromium-filled elemental analyzer coupled to an IRMS substantially improves the measurement quality and reliability for hydrogen isotopic compositions of organic substances (Cr-EA method). Hot chromium maximizes the yield of molecular hydrogen in a helium carrier gas by irreversibly and quantitatively scavenging all reactive elements except hydrogen. In contrast, under TC/EA conditions, heteroelements like nitrogen or chlorine (and other halogens) can form hydrogen cyanide (HCN) or hydrogen chloride (HCl) and this can cause isotopic fractionation. The Cr-EA technique thus expands the analytical possibilities for on-line hydrogen-isotope measurements of organic samples significantly. This method yielded reproducibility values (1-sigma) for δ2H measurements on water and caffeine samples of better than 1.0 and 0.5 mUr, respectively. To overcome handling problems with water as the principal calibration anchor for hydrogen isotopic measurements, we have employed an effective and simple strategy using reference waters or other liquids sealed in silver-tube segments. These crimped silver tubes can be employed in both the Cr-EA and TC/EA techniques. They simplify considerably the normalization of hydrogen-isotope measurement data to the VSMOW-SLAP (Vienna Standard Mean Ocean Water-Standard Light Antarctic Precipitation) scale, and their use improves accuracy of the data by eliminating evaporative loss and associated isotopic fractionation while handling water as a bulk sample. The calibration of organic samples, commonly having high δ2H values, will benefit from the availability of suitably 2H-enriched reference waters, extending the VSMOW-SLAP scale above zero.

Non-Chromate/No-VOC Coating System for DoD Applications

DTIC Science & Technology

2009-03-31

chromium species, at which point the corrosion protection capabilities suffer. Cr6+ is used everywhere that self - healing corrosion protection is...surface region in which the Cr6+ remains, forming a self - healing chemistry that re-protects if scratched. Thin (Class 3) chromate conversion layers are...olation polymer control color, thickness, and the self - healing property of the film [7]. TCP does not contain any free trivalent chromium and is free of

Investigation of the Performance of D 2O-Cooled High-Conversion Reactors for Fuel Cycle Calculations

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

Hiruta, Hikaru; Youinou, Gilles

2013-09-01

This report presents FY13 activities for the analysis of D 2O cooled tight-pitch High-Conversion PWRs (HCPWRs) with U-Pu and Th-U fueled cores aiming at break-even or near breeder conditions while retaining the negative void reactivity. The analyses are carried out from several aspects which could not be covered in FY12 activities. SCALE 6.1 code system is utilized, and a series of simple 3D fuel pin-cell models are developed in order to perform Monte Carlo based criticality and burnup calculations. The performance of U-Pu fueled cores with axial and internal blankets is analyzed in terms of their impact on the relativemore » fissile Pu mass balance, initial Pu enrichment, and void coefficient. In FY12, Pu conversion performances of D 2O-cooled HCPWRs fueled with MOX were evaluated with small sized axial/internal DU blankets (approximately 4cm of axial length) in order to ensure the negative void reactivity, which evidently limits the conversion performance of HCPWRs. In this fiscal year report, the axial sizes of DU blankets are extended up to 30 cm in order to evaluate the amount of DU necessary to reach break-even and/or breeding conditions. Several attempts are made in order to attain the milestone of the HCPWR designs (i.e., break-even condition and negative void reactivity) by modeling of HCPWRs under different conditions such as boiling of D 2O coolant, MOX with different 235U enrichment, and different target burnups. A similar set of analyses are performed for Th-U fueled cores. Several promising characteristics of 233U over other fissile like 239Pu and 235U, most notably its higher fission neutrons per absorption in thermal and epithermal ranges combined with lower ___ in the fast range than 239Pu allows Th-U cores to be taller than MOX ones. Such an advantage results in 4% higher relative fissile mass balance than that of U-Pu fueled cores while retaining the negative void reactivity until the target burnup of 51 GWd/t. Several other distinctions between U-Pu and Th-U fueled cores are identified by evaluating the sensitivity coefficients of keff, mass balance, and void coefficient. The effect of advanced iron alloy cladding (i.e., FeCrAl) on the performance of Pu conversion in MOX fueled cores is studied instead of using standard stainless-steel cladding. Variations in clad thickness and coolant-to-fuel volume ratio are also exercised. The use of FeCrAl instead of SS as a cladding alloy reduces the required Pu enrichment and improves the Pu conversion rate primarily due to the absence of nickel in the cladding alloy that results in the reduction of the neutron absorption. Also the difference in void coefficients between SS and FeCrAl alloys is nearly 500 pcm over the entire burnup range. The report also shows sensitivity and uncertainty analyses in order to characterize D 2O cooled HCPWRs from different aspects. The uncertainties of integral parameters (keff and void coefficient) for selected reactor cores are evaluated at different burnup points in order to find similarities and trends respect to D 2O-HCPWR.« less

An Open-Label Exploratory Study with Memantine: Correlation between Proton Magnetic Resonance Spectroscopy and Cognition in Patients with Mild to Moderate Alzheimer's Disease

PubMed Central

Gordon, Marc L.; Kingsley, Peter B.; Goldberg, Terry E.; Koppel, Jeremy; Christen, Erica; Keehlisen, Lynda; Kohn, Nina; Davies, Peter

2012-01-01

Aim To characterize progression of Alzheimer's disease (AD) using proton magnetic resonance spectroscopy (1H MRS). Methods Eleven subjects with mild to moderate AD underwent neurocognitive testing and single-voxel 1H MRS from the precuneus and posterior cingulate region at baseline, after 24 weeks of monotherapy with a cholinesterase inhibitor, and after another 24 weeks of combination therapy with open-label memantine and a cholinesterase inhibitor. Baseline metabolites [N-acetylaspartate (NAA), myo-inositol (mI), choline (Cho), and creatine (Cr)] and their ratios in AD subjects were compared with those of an age-matched control group of 28 cognitively normal subjects. Results AD subjects had significantly higher mI/Cr and lower NAA, NAA/Cr, NAA/Cho, and NAA/mI. Baseline Alzheimer's Disease Cooperative Study Activities of Daily Living (ADCS-ADL) scores significantly correlated with NAA/Cr, mI/Cr, and NAA/mI. There was an increase in mI and a decrease in NAA/mI, but no significant change in other metabolites or ratios, or neurocognitive measures, when memantine was added to a cholinesterase inhibitor. Conclusion Metabolite ratios significantly differed between AD and control subjects. Baseline metabolite ratios correlated with function (ADCS-ADL). There was an increase in mI and a decrease in NAA/mI, but no changes in other metabolites, ratios, or cognitive measures, when memantine was added to a cholinesterase inhibitor. PMID:22962555

Monitoring creatine and phosphocreatine by (13)C MR spectroscopic imaging during and after (13)C4 creatine loading: a feasibility study.

PubMed

Janssen, Barbara H; Lassche, Saskia; Hopman, Maria T; Wevers, Ron A; van Engelen, Baziel G M; Heerschap, Arend

2016-08-01

Creatine (Cr) supplementation to enhance muscle performance shows variable responses among individuals and different muscles. Direct monitoring of the supplied Cr in muscles would address these differences. In this feasibility study, we introduce in vivo 3D (13)C MR spectroscopic imaging (MRSI) of the leg with oral ingestion of (13)C4-creatine to observe simultaneously Cr and phosphocreatine (PCr) for assessing Cr uptake, turnover, and the ratio PCr over total Cr (TCr) in individual muscles. (13)C MRSI was performed of five muscles in the posterior thigh in seven subjects (two males and two females of ~20 years, one 82-year-old male, and two neuromuscular patients) with a (1)H/(13)C coil in a 3T MR system before, during and after intake of 15 % (13)C4-enriched Cr. Subjects ingested 20 g Cr/day for 4 days in four 5 g doses at equal time intervals. The PCr/TCr did not vary significantly during supplementation and was similar for all subjects and investigated muscles (average 0.71 ± 0.07), except for the adductor magnus (0.64 ± 0.03). The average Cr turnover rate, assessed in male muscles, was 2.1 ± 0.7 %/day. The linear uptake rates of Cr were variable between muscles, although not significantly different. This assessment was possible in all investigated muscles of young male volunteers, but less so in muscles of the other subjects due to lower signal-to-noise ratio. Improvements for future studies are discussed. In vivo (13)C MRSI after (13)C-Cr ingestion is demonstrated for longitudinal studies of Cr uptake, turnover, and PCr/TCr ratios of individual muscles in one exam.

Radiographic Risk Factors for Contralateral Rupture in Dogs with Unilateral Cranial Cruciate Ligament Rupture

PubMed Central

Chuang, Connie; Ramaker, Megan A.; Kaur, Sirjaut; Csomos, Rebecca A.; Kroner, Kevin T.; Bleedorn, Jason A.; Schaefer, Susan L.; Muir, Peter

2014-01-01

Background Complete cranial cruciate ligament rupture (CR) is a common cause of pelvic limb lameness in dogs. Dogs with unilateral CR often develop contralateral CR over time. Although radiographic signs of contralateral stifle joint osteoarthritis (OA) influence risk of subsequent contralateral CR, this risk has not been studied in detail. Methodology/Principal Findings We conducted a retrospective longitudinal cohort study of client-owned dogs with unilateral CR to determine how severity of radiographic stifle synovial effusion and osteophytosis influence risk of contralateral CR over time. Detailed survival analysis was performed for a cohort of 85 dogs after case filtering of an initial sample population of 513 dogs. This population was stratified based on radiographic severity of synovial effusion (graded on a scale of 0, 1, and 2) and severity of osteophytosis (graded on a scale of 0, 1, 2, and 3) of both index and contralateral stifle joints using a reproducible scoring method. Severity of osteophytosis in the index and contralateral stifles was significantly correlated. Rupture of the contralateral cranial cruciate ligament was significantly influenced by radiographic OA in both the index and contralateral stifles at diagnosis. Odds ratio for development of contralateral CR in dogs with severe contralateral radiographic stifle effusion was 13.4 at one year after diagnosis and 11.4 at two years. Odds ratio for development of contralateral CR in dogs with severe contralateral osteophytosis was 9.9 at one year after diagnosis. These odds ratios were associated with decreased time to contralateral CR. Breed, age, body weight, gender, and tibial plateau angle did not significantly influence time to contralateral CR. Conclusion Subsequent contralateral CR is significantly influenced by severity of radiographic stifle effusion and osteophytosis in the contralateral stifle, suggesting that synovitis and arthritic joint degeneration are significant factors in the disease mechanism underlying the arthropathy. PMID:25254499

Evaluation of potential sources of proteins in diets for rainbow trout (Oncorhynchus mykiss).

PubMed

Pfeffer, E; Henrichfreise, B

1994-01-01

7 diets were prepared containing as their only source of protein one of the following feeds: fish meal, casein, hydrolyzed feather meal, grieves, wheat gluten, maize gluten, soybean meal. Crystalline amino acids were supplemented except in cases of fish meal and casein to prevent specific amino acid deficiencies. Concentrations of N x 6.25 ranged between 436 and 457 g/kg dry matter (DM). Cr2O3 was added to each diet for indirect determination of digestibilities. Each diet was fed to triplicate groups of 20 rainbow trout of an average initial weight of 60 g. After 66 feeding days, all trout were killed and used for whole body analyses. Due to severely reduced intake, trout fed the casein based diet gained only about half as much weight as trout fed the fish meal based diet, though at the same fed conversion ratio of 1.0 kg gain per kg dietary DM. Gains on the other diets ranged between these two treatments with poorer feed conversion ratios. Digestibilities of crude protein of fish meal, casein, hydrolyzed feather meal, grieves, wheat gluten, maize gluten and soybean meal were: 86, 98, 67, 81, 97, 87, and 94%, respectively. The corresponding contents of digestible energy were: 21.2, 21.8, 15.4, 16.5, 19.6, 18.3, and 14.4 Mj/kg DM. Efficiency of utilization of digestible energy ranged between 43 and 54%, that of digestible crude protein between 32 and 41%.

Enhancement strategies for Cu(II), Cr(III) and Cr(VI) remediation by a variety of seaweed species.

PubMed

Murphy, V; Hughes, H; McLoughlin, P

2009-07-15

Various chemical treatments have been applied to six brown, red and green seaweed species with a view to enhancing their metal removal for Cu(II), Cr(III) and Cr(VI). Treatment with acetone resulted in the greatest enhancement for both cationic and anionic species with relatively low mass losses (15-35%), indicating its low risk to biomass operational stability. Cation binding was increased by 69%, while the total Cr removal was augmented by 15%. Cr(VI) binding was shown to be an adsorption-coupled reduction, whereby Cr(VI) was bound to the biomass surface at pH 2 and subsequently reduced to Cr(III). Acetone treatment also resulted in biomasses that were capable of converting up to 83% of Cr(VI) in solution to Cr(III). Blocking of carboxyl and amino functionalities had significant negative effects both on total Cr removal as well as percentage conversion of Cr(VI) to Cr(III). Results therefore indicated the significant role played by these moieties in metal binding to these seaweeds. Potentiometric titrations displayed agreement between the degree of esterification and the decrease in Cu(II) removal for Ulva spp. and Polysiphonia lanosa. FTIR analysis identified changes in biomass functionality and availability after chemical modification, the results of which were in agreement with metal removal studies. In conclusion, these biosorbents represent suitable candidates to replace conventional removal technologies for metal bearing wastewaters, in particular for the detoxification of hazardous Cr(VI) waste streams.

Increased N-Acetylaspartate/creatine ratio in the medial prefrontal cortex among unmedicated obsessive-compulsive disorder patients.

PubMed

Fan, Qing; Tan, Ling; You, Chao; Wang, Jijun; Ross, Colin A; Wang, Xuemei; Zhang, Tianhong; Li, Jianqi; Chen, Kemin; Xiao, Zeping

2010-10-01

Changes in the fronto-striato-thalamo-cortical-circuit loop have been suggested in the pathogenesis of obsessive-compulsive disorder (OCD), and have been studied using (1)H magnetic resonance spectroscopy ((1)H MRS) with interesting findings. However, whether neural metabolites are abnormal in the medial prefrontal cortex in patients with OCD is unknown. The purpose of the present study was to investigate neural metabolites in this brain region in a sample of patients with OCD. Subjects were 21 unmedicated OCD patients, including 10 who were drug-naïve, and 19 healthy controls. Single-voxel (1)H MRS was used to study the medial prefrontal cortex for each subject. Levels of N-acetylaspartate (NAA), choline-containing compounds and myoinositol were measured in terms of their ratios with creatine (Cr). The NAA/Cr ratio was significantly higher among OCD patients than among healthy controls (F = 4.76, P = 0.037). However, it did not correlate with patients' symptoms or with their illness durations. The NAA/Cr ratio also did not differ between drug-naïve and previously medicated patients. No significant group differences were found between OCD patients and normal controls for the choline-containing compounds/Cr or myoinositol/Cr ratios. In addition, a significant correlation between the NAA/Cr ratio and trait anxiety scores on the State-Trait Anxiety Inventory was found among the controls (r = 0.639, P = 0.010). The N-Acetylaspartate level relative to creatine in the medial prefrontal cortex was increased among unmedicated OCD patients. This cannot be attributed to the effect of medications. The possible significance of this finding in the pathophysiology of OCD is discussed. © 2010 Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine. Psychiatry and Clinical Neurosciences © 2010 Japanese Society of Psychiatry and Neurology.

X-Ray Absorption Near Edge Structure And Extended X-Ray Absorption Fine Structure Analysis of Standards And Biological Samples Containing Mixed Oxidation States of Chromium(III) And Chromium(VI)

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

Parsons, J.G.; Dokken, K.; Peralta-Videa, J.R.

For the first time a method has been developed for the extended X-ray absorption fine structure (EXAFS) data analyses of biological samples containing multiple oxidation states of chromium. In this study, the first shell coordination and interatomic distances based on the data analysis of known standards of potassium chromate (Cr(VI)) and chromium nitrate hexahydrate (Cr(III)) were investigated. The standards examined were mixtures of the following molar ratios of Cr(VI):Cr(III), 0:1, 0.25:0.75, 0.5:0.5, 0.75:0.25, and 1:0. It was determined from the calibration data that the fitting error associated with linear combination X-ray absorption near edge structure (LC-XANES) fittings was approximately {+-}10%more » of the total fitting. The peak height of the Cr(VI) pre-edge feature after normalization of the X-ray absorption (XAS) spectra was used to prepare a calibration curve. The EXAFS fittings of the standards were also investigated and fittings to lechuguilla biomass samples laden with different ratios of Cr(III) and Cr(VI) were performed as well. An excellent agreement between the XANES data and the data presented in the EXAFS spectra was observed. The EXFAS data also presented mean coordination numbers directly related to the ratios of the different chromium oxidation states in the sample. The chromium oxygen interactions had two different bond lengths at approximately 1.68 and 1.98 {angstrom} for the Cr(VI) and Cr(III) in the sample, respectively.« less

Pilot scale treatment of chromite ore processing residue using sodium sulfide in single reduction and coupled reduction/stabilization processes.

PubMed

Velasco, Antonio; Ramírez, Martha; Hernández, Sergio; Schmidt, Winfried; Revah, Sergio

2012-03-15

Single Cr(VI) reduction and coupled reduction/stabilization (R/S) processes were evaluated at pilot scale to determine their effectiveness to treat chromite ore processing residue (COPR). Sodium sulfide was used as the reducing agent and cement, gypsum and lime were tested as the stabilizing agents. The pilot experiments were performed in a helical ribbon blender mixer with batches of 250 kg of COPR and mixing time up to 30 min. Na2S/Cr(VI) mass ratios of 4.6, 5.7 and 6.8 were evaluated in the single reduction process to treat COPR with Cr(VI) concentration of ≈4.2 g/kg. The R/S process was tested with a Na2S/Cr(VI) mass ratio of 5.7 and including stabilizing agents not exceeding 5% (w/w(COPR)), to treat COPR with a Cr(VI) content of ≈5.1g/kg. The single reduction process with a ratio of 6.8, reached Cr(VI) reduction efficiencies up to 97.6% in the first days, however these values decreased to around 93% after 380 days of storage. At this point the total Cr level was around 12.5 mg/L. Cr(VI) removal efficiencies exceeding 96.5% were reached and maintained during 380 days when the coupled R/S process was evaluated. Total Cr levels lower than 5 mg/l were attained at the initials days in all R/S batch tested, however after 380 days, concentrations below the regulatory limit were only found with gypsum (2%) as single agent and with a blend of cement (4%) and lime (1%). These results indicated that the coupled R/S process is an excellent alternative to stabilize COPR. Copyright © 2011 Elsevier B.V. All rights reserved.

Novel Preparation of Nano-Composite CuO-Cr2O3 Using Ctab-Template Method and Efficient for Hydrogenation of Biomass-Derived Furfural

NASA Astrophysics Data System (ADS)

Yan, Kai; Wu, Xu; An, Xia; Xie, Xianmei

2013-02-01

A simple route to fabricate nano-composite oxides CuO-Cr2O3 using hexadecyltrimethylammonium bromide (CTAB)-templated Cu-Cr hydrotalcite as the precursor is presented. This novel method is based on CTAB-templating effect for mesostructure directing and using the cheap metal nitrate, followed by removal of CTAB. It was indicated that the nano-composite CuO-Cr2O3 was formed during the removal of CTAB. X-ray diffraction (XRD) and transitional electronic microscopy (TEM) revealed nice nano-composite oxides CuO-Cr2O3 were formed with high crystallinity. N2 adsorption and desorption indicated that a high surface area of 170.5 m2/g with a pore size of 2.7 nm of the nano-composite CuO-Cr2O3 was facilely resulted. The as-synthesized nano-composite oxides CuO-Cr2O3 display good catalytic activities for hydrogenation of furfural to furfuryl alcohol, whereas 86% selectivity was achieved at 75% conversion of furfural.

A Synthetic Calcite Standard for Determination of Relative Mn/Cr Sensitivity Factor

NASA Astrophysics Data System (ADS)

Fujiya, W.; Ichimura, K.; Takahata, N.; Sugiura, N.; Sano, Y.

2009-12-01

Primitive chondrites which suffered from aqueous alteration often contain carbonates such as calcites, dolomites and breunnerites. 53Mn-53Cr decay system (half-life: 3.7 Myr) is applicable to dating their precipitation and many authors have measured their Mn-Cr ages using the SIMS. However, the relative Mn/Cr sensitivity factor: RSF (measured Mn+/Cr+ ratio divided by the true ratio) is not well established due to the absence of suitable standards, therefore the ages have systematic uncertainties. We prepared a synthetic Mn and Cr bearing calcite to evaluate the Mn/Cr RSF. Here we report the technical details of preparation for the standard and its Mn/Cr RSF. We also measured the Mn/Cr RSF of San Carlos olivine which is often assumed to be the same as that of a carbonate, and compared it with that of our synthetic calcite. The Cr-bearing calcite was produced in a N2 filled closed system by the reaction Ca2+ + CO32- = CaCO3 in an aqueous solution. The reaction proceeded by continuous addition of ammonium carbonate vapor to the solution. The crystal size of the calcite was ~300 μm. A small amount of hydrazine was added to the solution in order to keep chromous ion from oxidation. Mn and Cr concentrations in the calcite grains were determined by the SEM-EDS. A weak, defocused beam was used due to prevent electron beam damage. In a spherical grain, radial zoning of Mn and Cr concentrations occur and they decrease towards the periphery. At the center of the grains, Mn and Cr concentrations are ~0.5 atomic % and the values of the Mn/Cr ratios are relatively constant. The Mn/Cr RSF was determined with the CAMECA NanoSIMS 50 at Ocean Research Institute of Univ. of Tokyo. A primary O- beam of ~1 nA and 5 μm diameter was used. 43Ca+, 52Cr+, 53Cr+ and 55Mn+ ions were analyzed in a combined peak-jumping/multi-detection mode. The total measurement time was typically ~20 minutes. The measurements were started after presputtering of 15 minutes. The mass resolution power was ~3500, sufficient to resolve all relevant isobaric interferences. Several points near the center of calcite grains with constant Mn and Cr concentrations were measured. As for San Carlos olivine, a primary beam was rastered over 20 x 20 μm2 areas. Signals of all ions decreased with time during the measurements. The 55Mn/52Cr RSF also decreased with time. Initially it was ~0.7-0.8, and approached to a nearly constant value of ~0.5-0.6 after ~20 minutes. 53Cr+/52Cr+ isotopic ratio was 0.1105 ± 0.0002 (1σ), not dependent on time and space. This value corresponds to ~-26 permil fractionation from the reference value. On the other hand, the RSF of San Carlos olivine was found to be ~0.9, consistent with previous studies. The RSF of our calcite is significantly lower than the values used in previous studies and the RSF of San Carlos olivine measured in this study. This implies that Mn-Cr ages for carbonates obtained in previous studies may have systematic biases (~3 Myr).

The Preparation of Porous Sol-Gel Silica with Metal Organic Framework MIL-101(Cr) by Microwave-Assisted Hydrothermal Method for Adsorption Chillers.

PubMed

Uma, Kasimayan; Pan, Guan-Ting; Yang, Thomas C-K

2017-06-02

Abst r act: Metal organic framework (MOF) of MIL-101(Cr)-Silica (SiO₂) composites with highly mesoporous and uniform dispersions were synthesized by a microwave-assisted hydrothermal method followed by the sol-gel technique. Water vapor adsorption experiments were conducted on the MIL-101(Cr)-SiO₂ composites for industrial adsorption chiller applications. The effects of MIL-101(Cr)-SiO₂ mixing ratios (ranging from 0% to 52%), the surface area and amount of Lewis and Brønsted sites were comprehensively determined through water vapor adsorption experiments and the adsorption mechanism is also explained. The BET and Langmuir results indicate that the adsorption isotherms associated with the various MIL-101(Cr)-SiO₂ ratios demonstrated Type I and IV adsorption behavior, due to the mesoporous structure of the MIL-101(Cr)-SiO₂. It was observed that the increase in the amount of Lewis and Brønsted sites on the MIL-101(Cr)-SiO₂ composites significantly improves the water vapor adsorption efficiency, for greater stability during the water vapor adsorption experiments.

[Treatment of wastewater containing Cr(VI) by LDH synthesizing in situ].

PubMed

Chen, Tian-hu; Feng, You-liang; Xu, Hui-fang; Peng, Shu-chuan; Huang, Chuan-hui; Tang, Shu-pei

2004-03-01

The objective of this work was to investigate the efficiency and factors impacting of removal Cr(VI) from wastewater by layer double hydroxide synthesizing in situ. Principle of the method may be described as follow: Mg2+ and Al3+ hydrolysis and forms Mg/Al-LDH by adding Mg2+, Al3+ and NaOH into wastewater containing Cr(VI), Cr(VI) anions are selectively intercalated into interlayer of LDH to balance positive structural charge. While Mg2+ and Al3+ co-precipitates and forms LDH, the Cr(VI) in wastewater is removal by settle of LDH synthesizing in situ, which are confirmed by analysis of X-ray diffraction on settle and chemical analysis on aqueous. The results indicate that factors of impacting on efficiency of removal Cr(VI) include in amount of adding Mg2+ and Al3+, Mg/Al ratio, pH and concentration of Cr(VI) in wastewater. The maximal removal efficiency of Cr(VI) can be reached when pH values are between 8.5 and 9, and Mg/Al ratios are between 1:1 and 2:1, meanwhile, Mg and Al added can be taken good use of. This technology has present extraordinary efficiency of wastewater treatment.

An investigation of automatic exposure control calibration for chest imaging with a computed radiography system.

PubMed

Moore, C S; Wood, T J; Avery, G; Balcam, S; Needler, L; Beavis, A W; Saunderson, J R

2014-05-07

The purpose of this study was to examine the use of three physical image quality metrics in the calibration of an automatic exposure control (AEC) device for chest radiography with a computed radiography (CR) imaging system. The metrics assessed were signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and mean effective noise equivalent quanta (eNEQm), all measured using a uniform chest phantom. Subsequent calibration curves were derived to ensure each metric was held constant across the tube voltage range. Each curve was assessed for its clinical appropriateness by generating computer simulated chest images with correct detector air kermas for each tube voltage, and grading these against reference images which were reconstructed at detector air kermas correct for the constant detector dose indicator (DDI) curve currently programmed into the AEC device. All simulated chest images contained clinically realistic projected anatomy and anatomical noise and were scored by experienced image evaluators. Constant DDI and CNR curves do not appear to provide optimized performance across the diagnostic energy range. Conversely, constant eNEQm and SNR do appear to provide optimized performance, with the latter being the preferred calibration metric given as it is easier to measure in practice. Medical physicists may use the SNR image quality metric described here when setting up and optimizing AEC devices for chest radiography CR systems with a degree of confidence that resulting clinical image quality will be adequate for the required clinical task. However, this must be done with close cooperation of expert image evaluators, to ensure appropriate levels of detector air kerma.

An investigation of automatic exposure control calibration for chest imaging with a computed radiography system

NASA Astrophysics Data System (ADS)

Moore, C. S.; Wood, T. J.; Avery, G.; Balcam, S.; Needler, L.; Beavis, A. W.; Saunderson, J. R.

2014-05-01

The purpose of this study was to examine the use of three physical image quality metrics in the calibration of an automatic exposure control (AEC) device for chest radiography with a computed radiography (CR) imaging system. The metrics assessed were signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and mean effective noise equivalent quanta (eNEQm), all measured using a uniform chest phantom. Subsequent calibration curves were derived to ensure each metric was held constant across the tube voltage range. Each curve was assessed for its clinical appropriateness by generating computer simulated chest images with correct detector air kermas for each tube voltage, and grading these against reference images which were reconstructed at detector air kermas correct for the constant detector dose indicator (DDI) curve currently programmed into the AEC device. All simulated chest images contained clinically realistic projected anatomy and anatomical noise and were scored by experienced image evaluators. Constant DDI and CNR curves do not appear to provide optimized performance across the diagnostic energy range. Conversely, constant eNEQm and SNR do appear to provide optimized performance, with the latter being the preferred calibration metric given as it is easier to measure in practice. Medical physicists may use the SNR image quality metric described here when setting up and optimizing AEC devices for chest radiography CR systems with a degree of confidence that resulting clinical image quality will be adequate for the required clinical task. However, this must be done with close cooperation of expert image evaluators, to ensure appropriate levels of detector air kerma.

Urinary Uric Acid/Creatinine Ratio - A Marker For Perinatal Asphyxia

PubMed Central

Patel, Kinjal Prahaladbhai; Makadia, Mayur Goradhanbhai; Patel, Vishwal Indravardan; Nilayangode, Haridas Neelakandan

2017-01-01

Background Perinatal hypoxia is one of the leading causes of perinatal mortality in developing countries. Both apgar score and arterial blood pH predict the neonatal mortality in asphyxia. Apgar score alone does not predict neurologic outcome and as it is influenced by various factors. This study was conducted to evaluate the utility and sensitivity of urinary uric acid to creatinine ratio (UA/Cr ratio) in asphyxia diagnosis, compared to invasive Arterial Blood Gas (ABG) analysis. Aim To assess the urinary uric acid/creatinine ratio as an additional marker for perinatal asphyxia compared with ABG analysis in apgar score monitoring. Materials and Methods The present case control study was conducted at a teaching hospital in Central Gujarat. Data of 40 healthy newborns and 40 asphyxiated newborns were collected. In absence of regional estimates, a sample of size 39 was required to attain a power of 80% at 5% alpha (type I error) considering a moderate effect size of 0.65. (UA/Cr) ratio was measured from the spot urine sample collected during 24-72 hours of birth. Statistical analysis was performed by Independent t-test, Pearson’s correlation coefficient (r) and Receiver Operating Characteristic (ROC) plots. Results The mean (UA/Cr ratio) (2.75±0.18 vs 1.78±0.23) is significantly higher in asphyxiated group than in the control group (p<0.0001). Urinary UA/Cr ratio had negative correlation with blood pH (r= -0.27, p=0.18), which was not significant (p>0.05). Urinary UA/Cr ratio with criterion of >2.3 had 100% sensitivity, 100% specificity with AUC of 1 (p<0.0001) had a better predictive value. Conclusions Apgar score is usually reduced in neonates with congenital anomalies and premature neonates. Hence, it is preferable that the clinical diagnosis of asphyxia by apgar scores be supported by other investigations so that early decision can be taken about the level of care the baby needs. pH, lactates and base deficits change with establishment of respiration following resuscitation. However, pH, lactate, base deficit estimations are invasive and need rapid estimations. Non-invasive urinary UA/Cr ratio may be an answer to these issues as it easy, economical and equally efficient. PMID:28274014

Results of a 2011 national questionnaire for investigation of mean glandular dose from mammography in Japan.

PubMed

Asada, Y; Suzuki, S; Minami, K; Shirakawa, S

2014-03-01

Diagnostic reference levels (DRLs) for mammography have yet to be created in Japan. A national questionnaire investigation into radiographic conditions in Japan was carried out for the purpose of creating DRLs. Items investigated included the following: tube voltage; tube current; current-time product; source-image distance; craniocaudal view; automatic exposure control (AEC) settings; name of mammography unit; image receptor system (computed radiography (CR), flat panel detector (FPD), or film/screen (F/S)); and supported or unsupported monitor diagnosis (including monitor resolution). Estimation of the mean glandular dose (MGD) for mammography was performed and compared with previous investigations. The MGD was 1.58(0.48) mGy, which did not significantly differ from a 2007 investigation. In relation to image receptors, although no difference in average MGD values was observed between CR and FPD systems, F/S systems had a significantly decreased value compared to both CR and FPDs. Concerning digital systems (FPDs), the MGD value of the direct conversion system was significantly higher than the indirect conversion system. No significant difference in MGD value was evident concerning type of monitor diagnosis for either the CR or the FPD digital systems; however, hard copies were used more often in CR. No significant difference in the MGD value was found in relation to monitor resolution. This report suggests ways to lower the doses patients undergoing mammography receive in Japan, and serves as reference data for 4.2 cm compressed breast tissue of 50% composition DRLs. Furthermore, our findings suggest that further optimisation of FPD settings can promote a reduction in the MGD value.

The reduction of CrVI to CrIII by the alpha and beta anomers of D-glucose in dimethyl sulfoxide. A comparative kinetic and mechanistic study.

PubMed

Signorella, S; Lafarga, R; Daier, V; Sala, L F

2000-02-11

The reduction of CrVI by alpha-D-glucose and beta-D-glucose was studied in dimethyl sulfoxide in the presence of pyridinium p-toluensulfonate, a medium where mutarotation is slower than the redox reaction. The two anomers reduce CrVI by formation of an intermediate CrVI ester precursor of the slow redox step. The equilibrium constant for the formation of the intermediate chromic ester and the rate of the redox steps are different for each anomer. alpha-D-Glucose forms the CrVI-Glc ester with a higher equilibrium constant than beta-D-glucose, but the electron transfer within this complex is slower than for the beta anomer. The difference is attributed to the better chelating ability of the 1,2-cis-diolate moiety of the alpha anomer. The CrV species, generated in the reaction mixture, reacts with the two anomers at a rate comparable with that of CrVI. The EPR spectra show that the alpha anomer forms several linkage isomers of the five-coordinate CrV bis-chelate, while beta-D-glucose affords a mixture of six-coordinate CrV monochelate and five-coordinate CrV bis-chelate. The conversion of the CrV mono- to bis-chelate is discussed in terms of the ability of the 1,2-cis- versus 1,2-trans-diolate moieties of the glucose anomers to bind CrV.

Proton MR spectroscopy in predicting the increase of perfusion MR imaging for WHO grade II gliomas.

PubMed

Guillevin, Remy; Menuel, Carole; Abud, Lucas; Costalat, Robert; Capelle, Laurent; Hoang-Xuan, Khê; Habas, Christophe; Chiras, Jacques; Vallée, Jean-Noel

2012-03-01

To investigate the correlation between the metabolite ratios obtained from proton magnetic resonance (MR) spectroscopy and those obtained from MR perfusion parameters (relative cerebral blood volume [rCBV]) in a cohort of low-grade glioma (LGG). Patients underwent prospectively conventional MR, proton magnetic resonance spectroscopy ((1) HMRS), and perfusion-weighted images (PWI). Statistical analyses were performed to determine the correlative and independent predictive factors of rCBVmax and the metabolite ratio thresholds with optimum sensitivity and specificity. Thirty-one patients were included in this study. Linear correlations were observed between the metabolic ratios (lactate [Lac]/creatine [Cr], choline [Cho]/N-acetyl-aspartate [NAA], free-lipids/Cr) and rCBVmax (P < 0.05). These metabolic ratios were determined to be independent predictive factors of rCBVmax (P = 0.027, 0.011 and 0.032, respectively). According to the receiver operating characteristic curves, the cutoff values of the metabolic ratios to discriminate between the two populations of rCBVmax (<1.7 versus = 1.7) were 1.72, 1.54, and 1.40, respectively, with a sensitivity = 75% and a specificity >95% for Lac/Cr. This study demonstrated consistent correlations between the data from (1) HMRS and PWI. The Lac/Cr ratio predicts regional hemodynamic changes, which are themselves a useful biomarker of clinical prognosis in patients with LGG. As such, this ratio may provide a new parameter for making improved clinical decisions. Copyright © 2011 Wiley-Liss, Inc.

Progress in Implementing Non-Cr6+ Surface Finishes for U.S. Navy and Marine Corps Aircraft

DTIC Science & Technology

2012-08-01

methods • Only qualified products to date for Class 1A are based on trivalent chromium • Key aspect overlooked: qualified products provide...date are based on trivalent chromium except one non-Cr • Similar passivation issues/potential changes as Class 1A coatings Aluminum Anodizing...including water, nickel, cobalt, trivalent chromium , and duplex Conversion coatings and Anodizing for Magnesium: SAE-AMS-M-3141 • Specification

Urine epidermal growth factor, monocyte chemoattractant protein-1 or their ratio as predictors of complete remission in primary glomerulonephritis.

PubMed

Chanrat, Eakkapat; Worawichawong, Supanat; Radinahamed, Piyanuch; Sathirapongsasuti, Nuankanya; Nongnuch, Arkom; Assanatham, Montira; Udomsubpayakul, Umaporn; Kitiyakara, Chagriya

2018-04-01

The balance of several cytokines likely influences the resolution of glomerulonephritis. Monocyte chemoattractant protein-1(MCP-1) is a chemokine that promotes renal inflammation whereas epidermal growth factor (EGF) stimulates protective responses. Previously, high urine MCP-1(MCP-1) and low urine EGF (EGF) levels were found to be associated with tubulointerstitial fibrosis, but there is limited information on the value of these mediators as predictors of therapeutic responses or long term outcome in primary glomerulonephritis. To determine the performance of urine EGF, MCP-1 or their ratio at baseline as biomarkers to predict complete remission, and the relationship of these mediators with subsequent renal function 24 months later in primary glomerulonephritis. This is a prospective study of patients with biopsy-proven primary glomerulonephritis. Baseline urine samples were collected at biopsy before therapy. MCP-1 and EGF were analyzed by enzyme-linked immunosorbent assays and expressed as a ratio to urine creatinine (ng/mgCr) or as EGF/MCP-1 ratio (ng/ng). Proteinuria and estimated glomerular filtration rate (eGRF) were monitored after therapy. Complete remission (CR) was defined as proteinuria ≤ 0.3 g/gCr. Median follow-up was 20 months. Of all patients (n = 74), 38 patients (51.4%) subsequently achieved CR. Baseline urine EGF and EGF/MCP-1 levels were significantly higher in CR compared to Not CR. By contrast, MCP-1 was not different. High EGF (EGF > 75 ng/mgCr) was a significant predictor (OR 2.28) for CR by multivariate analysis after adjusting for proteinuria, blood pressure, baseline eGFR. In patients who completed 24 months follow-up (n = 43), baseline EGF correlated inversely with proteinuria and positively with eGFR at 24 months. High urine EGF level is a promising biomarker of CR. Baseline EGF levels correlated with kidney function at 2 years. EGF/MCP-1 was not superior to EGF alone. Further studies are necessary to determine the role of urine EGF as a guide to therapy in primary GN. Copyright © 2018 Elsevier Ltd. All rights reserved.

Preparation and characterization of mesoporous ZnO-ZrO2 doped by Cr, Nd and Dy as a catalyst for conversion of coumarin using ultrasensitive fluorometric method

NASA Astrophysics Data System (ADS)

Ibrahim, M. M.

2017-04-01

Doping of mesoporous ZnO-ZrO2 nanoparticles with transition metal and lanthanides (Cr, Nd, Dy) were used as a catalyst to develop an ultrasensitive fluorometric method for the conversion of non fluorescent coumarin to highly fluorescent 7-hydroxycoumarin using H2O2 or light. It was found that doped- ZnO-ZrO2 mixed oxide can catalyze the decomposition of H2O2 to produce •OH radicals, which in turn convert coumarin to 7-hydroxycoumarin. At contrast, the doping has deleterious effect on conversion of coumarin by light due to high band gap and high concentrations of doping increase the recombination rate of electron and holes. Doped mixed oxides prepared by impregnation method and characterized by studying their structural, surface and optical properties. Chromium doped ZnO-ZrO2 had the highest rate of formation of hydroxyl radical due to decomposition of H2O2 and therefore 7-hydroxycoumarin due to surface area, small crystal size and high redox potential.

The influence of high fat diets with different ketogenic ratios on the hippocampal accumulation of creatine - FTIR microspectroscopy study

NASA Astrophysics Data System (ADS)

Skoczen, A.; Setkowicz, Z.; Janeczko, K.; Sandt, Ch.; Borondics, F.; Chwiej, J.

2017-09-01

The main purpose of this study was the determination and comparison of anomalies in creatine (Cr) accumulation occurring within CA3 and DG areas of hippocampal formation as a result of two high-fat, carbohydrate-restricted ketogenic diets (KD) with different ketogenic ratio (KR). To reach this goal, Fourier transformed infrared microspectroscopy with synchrotron radiation source (SRFTIR microspectroscopy) was applied for chemical mapping of creatine absorption bands, occurring around 1304, 1398 and 2800 cm- 1. The samples were taken from three groups of experimental animals: control group (N) fed with standard laboratory diet, KD1 and KD2 groups fed with high-fat diets with KR 5:1 and 9:1 respectively. Additionally, the possible influence on the phosphocreatine (PhCr, the high energetic form of creatine) content was evaluated by comparative analysis of chemical maps obtained for creatine and for compounds containing phosphate groups which manifest in the spectra at the wavenumbers of around 1240 and 1080 cm- 1. Our results showed that KD2 strongly modifies the frequency of Cr inclusions in both analyzed hippocampal areas. Statistical analysis, performed with Mann-Whitney U test revealed increased accumulation of Cr within CA3 and DG areas of KD2 fed rats compared to both normal rats and KD1 experimental group. Moreover, KD2 diet may modify the frequency of PhCr deposits as well as the PhCr to Cr ratio.

Increased myo-inositol level in dorsolateral prefrontal cortex in migraine patients with major depression.

PubMed

Lirng, Jiing-Feng; Chen, Hung-Chieh; Fuh, Jong-Ling; Tsai, Chia-Fen; Liang, Jen-Feng; Wang, Shuu-Jiun

2015-07-01

Although the comorbidity between migraine and major depressive disorder (MDD) has been recognized, the pathophysiology remains unclear. The dorsolateral prefrontal cortex (DLPFC) is a well-known neural substrate for MDD. We investigated the relationship between brain metabolites in DLPFC and comorbid MDD in migraine patients. We recruited migraine patients from a tertiary headache clinic. A board-certified psychiatrist conducted a structured interview for MDD diagnosis. The severity of depression was evaluated by the Beck Depression Inventory (BDI). Thirty migraine patients (five men, 25 women; mean age: 40.4 ± 12.4 years) completed the study, and 16 of them were diagnosed with MDD. All patients underwent a magnetic resonance spectroscopy (MRS) examination focusing on bilateral DLPFC. The ratios of N-acetylaspartate (NAA), choline (Cho), and myo-inositol (mI) to total creatine (tCr) were compared between migraine patients with and without MDD, and were correlated with BDI scores. Relative to patients without MDD, migraine patients with MDD had higher mI/tCr ratios in the bilateral DLPFC (p = 0.02, left; p = 0.02, right, Mann-Whitney U test). The mI/tCr ratios in the right DLPFC were positively correlated with BDI scores (r = 0.52, p = 0.003). The NAA/tCr and Cho/tCr ratios did not differ between migraine patients with and without MDD. Increased mI/tCr within the DLPFC might be associated with the presence of MDD in migraine patients. © International Headache Society 2014.

A New Method to Produce Ni-Cr Ferroalloy Used for Stainless Steel Production

NASA Astrophysics Data System (ADS)

Chen, Pei-Xian; Chu, Shao-Jun; Zhang, Guo-Hua

2016-08-01

A new electrosilicothermic method has been proposed in the present paper to produce Ni-Cr ferroalloy, which can be used for the production of 300 series stainless steel. Based on this new process, the Ni-Si ferroalloy is first produced as the intermediate alloy, and then the desiliconization process of Ni-Si ferroalloy melt with chromium concentrate is carried out to generate Ni-Cr ferroalloy. The silicon content in the Ni-Si ferroalloy produced in the submerged arc furnace should be more than 15 mass% (for the propose of reducing dephosphorization), in order to make sure the phosphorus content in the subsequently produced Ni-Cr ferroalloy is less than 0.03 mass%. A high utilization ratio of Si and a high recovery ratio of Cr can be obtained after the desiliconization reaction between Ni-Si ferroalloy and chromium concentrate in the electric arc furnace (EAF)-shaking ladle (SL) process.

Does transitioning from computed radiography (CR) to direct radiography (DR) with portable imaging systems affect workflow efficiency?

NASA Astrophysics Data System (ADS)

Gali, Raja L.; Roth, Christopher G.; Smith, Elizabeth; Dave, Jaydev K.

2018-03-01

In digital radiography, computed radiography (CR) technology is based on latent image capture by storage phosphors whereas direct radiography (DR) technology is based either on indirect conversion using a scintillator or direct conversion using a photoconductor. DR-based portable imaging systems may enhance workflow efficiency. The purpose of this work was to investigate changes in workflow efficiency at a tertiary healthcare center after transitioning from CR to DR technology for imaging with portable x-ray units. An IRB exemption was obtained. Data for all inpatient-radiographs acquired with portable x-ray units from July-2014 till June-2015 (period 1) with CR technology (AMX4 or AMX4+ portable unit from GE Healthcare, NX workstation from Agfa Healthcare for digitization), from July-2015 till June-2016 (period 2) with DR technology (Carestream DRX-Revolution x-ray units and DRX-1C image receptors) and from July-2016 till January-2017 (period 3; same DR technology) were extracted using Centricity RIS-IC (GE Healthcare). Duration between the imaging-examination scheduled time and completed time (timesch-com) was calculated and compared using non-parametric tests (between the three time periods with corrections for multiple comparisons; three time periods were used to identify if there were any other potential temporal trends not related to transitioning from CR to DR). IBM's SPSS package was used for statistical analysis. Overall data was obtained from 33131, 32194, and 18015 cases in periods 1, 2 and 3, respectively. Independent-Samples Kruskal-Wallis test revealed a statistically significant difference in timesch-com across the three time periods (χ2(2, n= 83,340) = 2053, p < 0.001). The timesch-com was highest for period 1 i.e., radiographs acquired with CR technology (median: 64 minutes) and it decreased significantly for radiographs acquired with DR technology in periods 2 (median: 49 minutes; p < 0.001) and 3 (median∶ 44 minutes; p < 0.001). Overall, adoption of DR technology resulted in a drop in timesch-com by 27% relative to the use of CR technology. Transitioning from CR to DR was associated with improved workflow efficiency for radiographic imaging with portable x-ray units.

Risk Stratification of Acute Kidney Injury Using the Blood Urea Nitrogen/Creatinine Ratio in Patients With Acute Decompensated Heart Failure.

PubMed

Takaya, Yoichi; Yoshihara, Fumiki; Yokoyama, Hiroyuki; Kanzaki, Hideaki; Kitakaze, Masafumi; Goto, Yoichi; Anzai, Toshihisa; Yasuda, Satoshi; Ogawa, Hisao; Kawano, Yuhei

2015-01-01

Risk stratification of acute kidney injury (AKI) is important for acute decompensated heart failure (ADHF). The aim of this study was to determine whether clinical markers, such as the blood urea nitrogen/creatinine ratio (BUN/Cr) or BUN or creatinine values alone, stratify the risk of AKI for mortality. In all, 371 consecutive ADHF patients were enrolled in the study. AKI was defined as serum creatinine ≥0.3 mg/dl or a 1.5-fold increase in serum creatinine levels within 48 h. During ADHF therapy, AKI occurred in 99 patients; 55 patients died during the 12-month follow-up period. Grouping patients according to AKI and a median BUN/Cr at admission of 22.1 (non-AKI+low BUN/Cr, non-AKI+high BUN/Cr, AKI+low BUN/Cr, and AKI+high BUN/Cr groups) revealed higher mortality in the AKI+high BUN/Cr group (log-rank test, P<0.001). Cox's proportional hazard analysis revealed an association between AKI+high BUN/Cr and mortality, whereas the association with AKI+low BUN/Cr did not reach statistical significance. When patients were grouped according to AKI and median BUN or creatinine values at admission, AKI was associated with mortality, regardless of BUN or creatinine. The combination of AKI and elevated BUN/Cr, but not BUN or creatinine individually, is linked with an increased risk of mortality in ADHF patients, suggesting that the BUN/Cr is useful for risk stratification of AKI.

Fabrication and characterization of He-charged ODS-FeCrNi films deposited by a radio-frequency plasma magnetron sputtering technique

NASA Astrophysics Data System (ADS)

Song, Liang; Wang, Xianping; Wang, Le; Zhang, Ying; Liu, Wang; Jiang, Weibing; Zhang, Tao; Fang, Qianfeng; Liu, Changsong

2017-04-01

He-charged oxide dispersion strengthened (ODS) FeCrNi films were prepared by a radio-frequency (RF) plasma magnetron sputtering method in a He and Ar mixed atmosphere at 150 °C. As a comparison, He-charged FeCrNi films were also fabricated at the same conditions through direct current (DC) plasma magnetron sputtering. The doping of He atoms and Y2O3 in the FeCrNi films was realized by the high backscattered rate of He ions and Y2O3/FeCrNi composite target sputtering method, respectively. Inductive coupled plasma (ICP) and x-ray photoelectron spectroscopy (XPS) analysis confirmed the existence of Y2O3 in FeCrNi films, and Y2O3 content hardly changed with sputtering He/Ar ratio. Cross-sectional scanning electron microscopy (SEM) shows that the FeCrNi films were composed of dense columnar nanocrystallines and the thickness of the films was obviously dependent on He/Ar ratio. Nanoindentation measurements revealed that the FeCrNi films fabricated through DC/RF plasma magnetron sputtering methods exhibited similar hardness values at each He/Ar ratio, while the dispersion of Y2O3 apparently increased the hardness of the films. Elastic recoil detection (ERD) showed that DC/RF magnetron sputtered FeCrNi films contained similar He amounts (˜17 at.%). Compared with the minimal change of He level with depth in DC-sputtered films, the He amount decreases gradually in depth in the RF-sputtered films. The Y2O3-doped FeCrNi films were shown to exhibit much smaller amounts of He owing to the lower backscattering possibility of Y2O3 and the inhibition effect of nano-sized Y2O3 particles on the He element.

Marine and freshwater concentration ratios (CR(wo-water)): review of Japanese data.

PubMed

Tagami, K; Uchida, S

2013-12-01

The water-to-organism (whole body) concentration ratio (CR(wo-water)), which is defined as the ratio of the concentration of a radionuclide in the biota (Bq kg(-1) fresh weight) to that in water (Bq L(-1)), has been used in mathematical models for environmental radiation protection. In the present paper, published global fallout (90)Sr, (137)Cs, (106)Ru, (144)Ce and (239+240)Pu activity concentration data and stable element concentration data for Na, K, Ca, Mg, Fe, Cu and Mn for organisms living in freshwater or seawater areas in Japan were collated. The data suitable for obtaining CR(wo-water) values were identified. CR(wo-water) values of (137)Cs were similar for pelagic fish, benthic fish and whitebait (immature, small fish) with respective geometric means of 30 (range: 4.4-69), 32 (range: 15-54) and 33 (range: 13-84). The calculated CR(wo-water) values of the other radionuclides and stable elements were generally similar to other previously reported values; with the exception that those for Ce were lower for marine biota and those of Cu were higher for freshwater fish. Copyright © 2012 Elsevier Ltd. All rights reserved.

MSFR TRU-burning potential and comparison with an SFR

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

Fiorina, C.; Cammi, A.; Franceschini, F.

2013-07-01

The objective of this work is to evaluate the Molten Salt Fast Reactor (MSFR) potential benefits in terms of transuranics (TRU) burning through a comparative analysis with a sodium-cooled FR. The comparison is based on TRU- and MA-burning rates, as well as on the in-core evolution of radiotoxicity and decay heat. Solubility issues limit the TRU-burning rate to 1/3 that achievable in traditional low-CR FRs (low-Conversion-Ratio Fast Reactors). The softer spectrum also determines notable radiotoxicity and decay heat of the equilibrium actinide inventory. On the other hand, the liquid fuel suggests the possibility of using a Pu-free feed composed onlymore » of Th and MA (Minor Actinides), thus maximizing the MA burning rate. This is generally not possible in traditional low-CR FRs due to safety deterioration and decay heat of reprocessed fuel. In addition, the high specific power and the lack of out-of-core cooling times foster a quick transition toward equilibrium, which improves the MSFR capability to burn an initial fissile loading, and makes the MSFR a promising system for a quick (i.e., in a reactor lifetime) transition from the current U-based fuel cycle to a novel closed Th cycle. (authors)« less

Genesis of Cr(VI) in Sri Lankan soils and its adsorptive removal by calcined gibbsite

NASA Astrophysics Data System (ADS)

Rajapaksha, A. U.; Wijesundara, D. M.; Vithanage, M. S.; Ok, Y. S.

2012-12-01

Hexavalent chromium is highly toxic to biota and considered as a priority pollutant. Industrial sources of Cr(VI) include leather tanning, plating, electroplating, anodizing baths, rinse waters, etc. In addition, weathering of ultramafic rocks rich in chromium, such as serpentine, is known to Cr(VI) sources into natural water. The Cr(III) is the most stable in the environment, however, conversion of Cr(III) into Cr(VI) occurs in soil due to presence of naturally occurring minerals such as manganese dioxides. We investigated the amount of Cr(VI) recorded from the soils from anthropogenically and naturally contaminated soils (serpentine soils) in Sri Lanka and the removal efficacy of Cr(VI) by calcined gibbsite (Al oxides). The effect of pH on Cr(VI) adsorption was determined by adjusting the pH in the range of 4-10. In the experiments, the adsorbent concentration was kept at 1 g/l of solution containing 10 mg/l Cr(VI) at 25 0C. Total chromium recorded were around 11,000 mg kg-1 and 6,000 mg kg-1 for serpentine soil and tannery waste-contaminated soil, respectively. Although total Cr was high in the contaminated soils, Cr(VI) concentration was only about 28 mg kg-1 and 210 mg kg-1 in the serpentine and tannery soils, respectively. The calcined gibbsite has maximum adsorption of 85 % around pH 4 and adsorption generally decreased with increase of pH.

Impact of Fe(III) as an effective electron-shuttle mediator for enhanced Cr(VI) reduction in microbial fuel cells: Reduction of diffusional resistances and cathode overpotentials.

PubMed

Wang, Qiang; Huang, Liping; Pan, Yuzhen; Quan, Xie; Li Puma, Gianluca

2017-01-05

The role of Fe(III) was investigated as an electron-shuttle mediator to enhance the reduction rate of the toxic heavy metal hexavalent chromium (Cr(VI)) in wastewaters, using microbial fuel cells (MFCs). The direct reduction of chromate (CrO 4 - ) and dichromate (Cr 2 O 7 2- ) anions in MFCs was hampered by the electrical repulsion between the negatively charged cathode and Cr(VI) functional groups. In contrast, in the presence of Fe(III), the conversion of Cr(VI) and the cathodic coulombic efficiency in the MFCs were 65.6% and 81.7%, respectively, 1.6 times and 1.4 folds as those recorded in the absence of Fe(III). Multiple analytical approaches, including linear sweep voltammetry, Tafel plot, cyclic voltammetry, electrochemical impedance spectroscopy and kinetic calculations demonstrated that the complete reduction of Cr(VI) occurred through an indirect mechanism mediated by Fe(III). The direct reduction of Cr(VI) with cathode electrons in the presence of Fe(III) was insignificant. Fe(III) played a critical role in decreasing both the diffusional resistance of Cr(VI) species and the overpotential for Cr(VI) reduction. This study demonstrated that the reduction of Cr(VI) in MFCs was effective in the presence of Fe(III), providing an alternative and environmentally benign approach for efficient remediation of Cr(VI) contaminated sites with simultaneous production of renewable energy. Copyright © 2016 Elsevier B.V. All rights reserved.

The effect of epileptic seizures on proton MRS visible neurochemical concentrations.

PubMed

Simister, Robert J; McLean, Mary A; Salmenpera, Tuuli M; Barker, Gareth J; Duncan, John S

2008-09-01

To investigate post-ictal changes in cerebral metabolites. We performed a longitudinal quantitative proton magnetic resonance spectroscopy (MRS) study in 10 patients with epilepsy and 10 control subjects. The patients were studied on two occasions: immediately following a seizure, and on a second occasion at least 7h after the most recent seizure. Each study measured N-acetyl aspartate plus N-acetyl aspartyl glutamate (NAAt), Creatine plus phosphocreatine (Cr), Choline containing compounds (Cho) and glutamate plus glutamine (GLX) concentrations using a short-echo time sequence (TE=30ms), and NAAt, Cr and lactate using a second sequence with longer echo time (TE=144ms). The control group was studied on two occasions using the same sequences. No inter-scan differences were observed for the control group. NAAt and NAAt/Cr levels were lower in the patient group at both measured TEs but did not change significantly between studies. The ratio of Cr at TE 144ms to TE 30ms (Cr(144)/Cr(30)) and GLX/Cr were higher and Cho lower in the post-ictal scan compared to the inter-ictal study. Change in Cr(144)/Cr(30) and NAAt(144)/Cr(144) correlated with the post-ictal interval. Lactate measurement at longer TE was not informative. Proton MRS is sensitive to metabolite changes following epileptic seizures within the immediate post-ictal period. The ratio Cr(144)/Cr(30) is the most sensitive measure of metabolic disturbance and is highest in the post-ictal period but appears to normalise within 2h of the most recent seizure.

Differential effect of biochar upon reduction-induced mobility and bioavailability of arsenate and chromate.

PubMed

Choppala, Girish; Bolan, Nanthi; Kunhikrishnan, Anitha; Bush, Richard

2016-02-01

Heavy metals such as chromium (Cr) and arsenic (As) occur in ionic form in soil, with chromate [Cr(VI)] and arsenate As(V) being the most pre-dominant forms. The application of biochar to Cr(VI) and As(V) spiked and field contaminated soils was evaluated on the reduction processes [(Cr(VI) to Cr(III)] and [As(V) to As(III))], and subsequent mobility and bioavailability of both As(V) and Cr(VI). The assays used in this study included leaching, soil microbial activity and XPS techniques. The reduction rate of As(V) was lower than that of Cr(VI) with and without biochar addition, however, supplementation with biochar enhanced the reduction process of As(V). Leaching experiments indicated Cr(VI) was more mobile than As(V). Addition of biochar reversed the effect by reducing the mobility of Cr and increasing that of As. The presence of Cr and As in both spiked and contaminated soils reduced microbial activity, but with the addition of biochar to these soils, the microbial activity increased in the Cr(VI) contaminated soils, while it was further decreased with As(V) contaminated soils. The addition of biochar was effective in mitigating Cr toxicity by reducing Cr(VI) to Cr(III). In contrast, the conversion process of As(V) to As(III) hastened by biochar was not favourable, as As(III) is more toxic in soils. Overall, the presence of functional groups on biochar promotes reduction by providing the electrons required for reduction processes to occur as determined by XPS data. Copyright © 2015 Elsevier Ltd. All rights reserved.

Elastic Modulus Measurement of ORNL ATF FeCrAl Alloys

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

Thompson, Zachary T.; Terrani, Kurt A.; Yamamoto, Yukinori

2015-10-01

Elastic modulus and Poisson’s ratio for a number of wrought FeCrAl alloys, intended for accident tolerant fuel cladding application, are determined via resonant ultrasonic spectroscopy. The results are reported as a function of temperature from room temperature to 850°C. The wrought alloys were in the fully annealed and unirradiated state. The elastic modulus for the wrought FeCrAl alloys is at least twice that of Zr-based alloys over the temperature range of this study. The Poisson’s ratio of the alloys was 0.28 on average and increased very slightly with increasing temperature.

Serum and urinary thioredoxin concentrations are associated with severity of children hydronephrosis.

PubMed

Xu, Zhe-Ming; Li, Min-Ju; Tao, Chang

2017-03-01

Ureteropelvic junction obstruction (UPJO) is the most common cause of hydronephrosis in children. This study was to assess the relationship between serum thioredoxin (S-Trx) and urinary thioredoxin (U-Trx) concentrations and severity of children hydronephrosis caused by UPJO. This study included 156 hydronephrosis children with unilateral UPJO and 80 healthy children. S-Trx and U-Trx concentrations were measured using enzyme-linked immunosorbent assay. U-Trx/creatinine (cr) ratio was calculated. S-Trx and U-Trx concentrations and U-Trx/cr ratio were significantly higher in hydronephrosis children than in healthy children. They were significantly correlated with split renal function, anterior-posterior diameter and Society for Fetal Urology classification, as well as were independently related to the split renal function <39.2%, anterior-posterior diameter>30mm and Society for Fetal Urology grade IV. Under receiver operating characteristic curves, U-Trx/cr ratio showed the higher predictive value compared to S-Trx and U-Trx concentrations. Increased S-Trx and U-Trx concentrations, especially U-Trx/cr ratio, are closely associated with the severity of children hydronephrosis, substantializing Trx as a promising biomarker for the progression of children hydronephrosis. Copyright © 2017 Elsevier B.V. All rights reserved.

Physiological, physical and behavioural changes in dogs (Canis familiaris) when kennelled: testing the validity of stress parameters.

PubMed

Part, C E; Kiddie, J L; Hayes, W A; Mills, D S; Neville, R F; Morton, D B; Collins, L M

2014-06-22

Domestic dogs (Canis familiaris) housed in kennelling establishments are considered at risk of suffering poor welfare. Previous research supporting this hypothesis has typically used cortisol:creatinine ratios (C/Cr) to measure acute and chronic stress in kennelled dogs. However, the value of C/Cr as a welfare indicator has been questioned. This study aimed to test the validity of a range of physiological, physical and behavioural welfare indicators and to establish baseline values reflecting good dog welfare. Measurements were taken from 29 privately-owned dogs (14 males, 15 females), ranging in age and breed, in their own home and in a boarding kennel environment, following a within-subjects, counterbalanced design. Pairwise comparisons revealed that C/Cr and vanillylmandelic acid:creatinine ratios (VMA/Cr) were higher in the kennel than home environment (P=0.003; P=0.01, respectively) and were not associated with differences in movement/exercise between environments. Dogs' surface temperature was lower in kennels (P=0.001) and was not associated with ambient temperature. No association with age, or effects of kennel establishment, kennelling experience, sex or source were found. Dogs were generally more active in kennels, but showed considerable individual variability. C/Cr and 5-HIAA:creatinine ratios (5-HIAA/Cr) were negatively correlated with lip licking in kennels. Baseline values for each parameter are presented. The emotional valence of responses was ambiguous and no definitive evidence was found to suggest that dogs were negatively stressed by kennelling. It was concluded that C/Cr and, particularly, VMA/Cr and surface temperature provide robust indicators of psychological arousal in dogs, while spontaneous behaviour might be better used to facilitate interpretation of physiological and physical data on an individual level. Copyright © 2014 Elsevier Inc. All rights reserved.

Fast quantification of proton magnetic resonance spectroscopic imaging with artificial neural networks

NASA Astrophysics Data System (ADS)

Bhat, Himanshu; Sajja, Balasrinivasa Rao; Narayana, Ponnada A.

2006-11-01

Accurate quantification of the MRSI-observed regional distribution of metabolites involves relatively long processing times. This is particularly true in dealing with large amount of data that is typically acquired in multi-center clinical studies. To significantly shorten the processing time, an artificial neural network (ANN)-based approach was explored for quantifying the phase corrected (as opposed to magnitude) spectra. Specifically, in these studies radial basis function neural network (RBFNN) was used. This method was tested on simulated and normal human brain data acquired at 3T. The N-acetyl aspartate (NAA)/creatine (Cr), choline (Cho)/Cr, glutamate + glutamine (Glx)/Cr, and myo-inositol (mI)/Cr ratios in normal subjects were compared with the line fitting (LF) technique and jMRUI-AMARES analysis, and published values. The average NAA/Cr, Cho/Cr, Glx/Cr and mI/Cr ratios in normal controls were found to be 1.58 ± 0.13, 0.9 ± 0.08, 0.7 ± 0.17 and 0.42 ± 0.07, respectively. The corresponding ratios using the LF and jMRUI-AMARES methods were 1.6 ± 0.11, 0.95 ± 0.08, 0.78 ± 0.18, 0.49 ± 0.1 and 1.61 ± 0.15, 0.78 ± 0.07, 0.61 ± 0.18, 0.42 ± 0.13, respectively. These results agree with those published in literature. Bland-Altman analysis indicated an excellent agreement and minimal bias between the results obtained with RBFNN and other methods. The computational time for the current method was 15 s compared to approximately 10 min for the LF-based analysis.

Effect of the patient education - Learning and Coping strategies - in cardiac rehabilitation on return to work at one year: a randomised controlled trial show (LC-REHAB).

PubMed

Bitsch, Birgitte Laier; Nielsen, Claus Vinther; Stapelfeldt, Christina Malmose; Lynggaard, Vibeke

2018-05-21

Personal resources are identified as important for the ability to return to work (RTW) for patients with ischaemic heart disease (IHD) or heart failure (HF) undergoing cardiac rehabilitation (CR). The patient education 'Learning and Coping' (LC) addresses personal resources through a pedagogical approach. This trial aimed to assess effect of adding LC strategies in CR compared to standard CR measured on RTW status at one-year follow-up after CR. In an open parallel randomised controlled trial, patients with IHD or HF were block-randomised in a 1:1 ratio to the LC arm (LC plus CR) or the control arm (CR alone) across three Danish hospital units. Eligible patients were aged 18 to ≤60 and had not left the labour market. The intervention was developed from an inductive pedagogical approach consisting of individual interviews and group based teaching by health professionals with experienced patients as co-educators. The control arm consisted of deductive teaching (standard CR). RTW status was derived from the Danish Register for Evaluation of Marginalisation (DREAM). Blinding was not possible. The effect was evaluated by logistic regression analysis and reported as crude and adjusted odds ratios (OR) with 95% confidence interval (CI). The population for the present analysis was N = 244 (LC arm: n = 119 versus control arm: n = 125). No difference in RTW status was found at one year across arms (LC arm: 64.7% versus control arm: 68.8%, adjusted odds ratio OR: 0.76, 95% CI: 0.43-1.31). Addition of LC strategies in CR showed no improvement in RTW at one year follow-up. www.clinicaltrials.gov identifier NCT01668394. First Posted: August 20, 2012.

Synthesis and energy transfer studies of LaMgAl{sub 11}O{sub 19}:Cr{sup 3+}, Nd{sup 3+} phosphors

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

Zhu, Jicheng; Xia, Zhiguo; Liu, Quanlin, E-mail: qlliu@ustb.edu.cn

2016-02-15

Highlights: • Cr{sup 3+}/Nd{sup 3+} co-doped LaMgAl{sub 11}O{sub 19} phosphors were synthesized. • The energy transfer mechanism is ascribed to the dipole–quadrupole interaction. • The materials can convert the UV–vis light into near-infrared emission. - Abstract: Cr{sup 3+}/Nd{sup 3+} co-activated LaMgAl{sub 11}O{sub 19} phosphors have been synthesized by high temperature solid-state method. In the LaMgAl{sub 11}O{sub 19}:Cr{sup 3+}/Nd{sup 3+} system, Cr{sup 3+} can absorb the UV–vis photons (350–650 nm), and then energy transfer takes place between Cr{sup 3+} and Nd{sup 3+}, and finally the samples give near infrared emission originated from Nd{sup 3+}. Energy transfer from Cr{sup 3+} to Nd{supmore » 3+} is discussed via the variations of the lifetime values of Cr{sup 3+}, and the mechanism has been ascribed to the dipole–quadrupole interaction. The absorption of Cr{sup 3+} in the visible region and the following energy transfer from Cr{sup 3+} to Nd{sup 3+} indicated that the material can potentially serve as spectral convertors to improve the photovoltaic conversion efficiency of silicon-based solar cell.« less

CrIII as an alternative to RuII in metallo-supramolecular chemistry.

PubMed

Zare, Davood; Doistau, Benjamin; Nozary, Homayoun; Besnard, Céline; Guénée, Laure; Suffren, Yan; Pelé, Anne-Laure; Hauser, Andreas; Piguet, Claude

2017-07-18

Compared to divalent ruthenium coordination complexes, which are widely exploited as parts of multi-component photonic devices, optically active trivalent chromium complexes are under-represented in multi-metallic supramolecular architectures performing energy conversion mainly because of the tricky preparation of stable heteroleptic Cr III building blocks. We herein propose some improvements with the synthesis of a novel family of kinetically inert heteroleptic bis-terdentate mononuclear complexes, which can be incorporated into dinuclear rod-like dyads as a proof-of-concept. The mechanism and magnitude of intermetallic CrCr communication have been unraveled by a combination of magnetic, photophysical and thermodynamic investigations. Alternated aromatic/alkyne connectors provided by Sonogashira coupling reactions emerge as the most efficient wires for long-distance communication between two chromium centres bridged by Janus-type back-to-back bis-terdentate receptors.

Inductively coupled plasma mass spectrometry with a twin quadrupole instrument using laser ablation sample introduction and monodisperse dried microparticulate injection

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

Allen, Lloyd A.

1996-10-17

The focus of this dissertation is the use of a twin quadrupole inductively coupled plasma mass spectrometer (ICP-MS) for the simultaneous detection of two m/z values. The twin quadrupole ICP-MS is used with laser ablation sample introduction in both the steady state (10 Hz) and single pulse modes. Steady state signals are highly correlated and the majority of flicker noise cancels when the ratio is calculated. Using a copper sample, the isotope ratio 63Cu +/ 65Cu + is measured with a relative standard deviation (RSD) of 0.26%. Transient signals for single laser pulses are also obtained. Copper isotope ratio measurementsmore » for several laser pulses are measured with an RSD of 0.85%. Laser ablation (LA) is used with steel samples to assess the ability of the twin quadrupole ICP-MS to eliminate flicker noise of minor components of steel samples. Isotopic and internal standard ratios are measured in the first part of this work. The isotope ratio 52Cr +/ 53Cr + (Cr present at 1.31 %) can be measured with an RSD of 0.06 % to 0.1 %. For internal standard elements, RSDs improve from 1.9 % in the Cr + signal to 0.12% for the ratio of 51V + to 52Cr +. In the second part of this work, one mass spectrometer is scanned while the second channel measures an individual m/z value. When the ratio of these two signals is calculated, the peak shapes in the mass spectrum are improved significantly. Pulses of analyte and matrix ions from individual drops are measured simultaneously using the twin quadrupole ICP-MS with monodisperse dried microparticulate injection (MDMI). At modest Pb concentrations (500 ppm), a shoulder on the leading edge of the Li + signal becomes apparent. Space charge effects are consistent with the disturbances seen.« less

[Comparison among three translucency parameters].

PubMed

Fang, Xiong; Hui, Xia

2017-06-01

This study aims to compare the three commonly used translucency parameters in prosthodontics: transmittance (T), contrast ratio (CR), and translucency parameter (TP). Six platelet specimens were composed of Vita enamel and dental porcelain. The initial thickness was 1.2 mm. The specimens were gradually ground to 1.0, 0.8, 0.6, 0.4, and 0.2 mm. T, color parameters, and reflection were measured by a spectrocolorimeter for each corresponding thickness. T, CR and TP were calculated and compared. TP increased, whereas CR decreased, with decreasing thickness. Moreover, 
T increased with decreasing thickness, and exponential relationships were found. Two-way ANOVA showed statistical significance between T and thickness, except between T and the 1.2 mm and 1.0 mm enamel porcelain groups. No difference was found among the coefficient variations (CV) of T, CR and TP. Curve fitting indicated the existence of exponential relationships between T and CR and between T and TP. The values for goodness of fit with statistical significance were 0.951 and 0.939, respectively (P<0.05). Under the experimental conditions, T, TP and CR achieved the same CV. T and TP, as well as T and CR, were found with exponential relationships. The value of CR and TP could not represent the translucency precisely, especially when comparing the changing ratios.

Ocular biometric parameters among 3-year-old Chinese children: testability, distribution and association with anthropometric parameters

PubMed Central

Huang, Dan; Chen, Xuejuan; Gong, Qi; Yuan, Chaoqun; Ding, Hui; Bai, Jing; Zhu, Hui; Fu, Zhujun; Yu, Rongbin; Liu, Hu

2016-01-01

This survey was conducted to determine the testability, distribution and associations of ocular biometric parameters in Chinese preschool children. Ocular biometric examinations, including the axial length (AL) and corneal radius of curvature (CR), were conducted on 1,688 3-year-old subjects by using an IOLMaster in August 2015. Anthropometric parameters, including height and weight, were measured according to a standardized protocol, and body mass index (BMI) was calculated. The testability was 93.7% for the AL and 78.6% for the CR overall, and both measures improved with age. Girls performed slightly better in AL measurements (P = 0.08), and the difference in CR was statistically significant (P < 0.05). The AL distribution was normal in girls (P = 0.12), whereas it was not in boys (P < 0.05). For CR1, all subgroups presented normal distributions (P = 0.16 for boys; P = 0.20 for girls), but the distribution varied when the subgroups were combined (P < 0.05). CR2 presented a normal distribution (P = 0.11), whereas the AL/CR ratio was abnormal (P < 0.001). Boys exhibited a significantly longer AL, a greater CR and a greater AL/CR ratio than girls (all P < 0.001). PMID:27384307

Contrast volume to creatinine clearance ratio for the prediction of contrast-induced nephropathy in patients undergoing coronary angiography or percutaneous intervention.

PubMed

Barbieri, Lucia; Verdoia, Monica; Marino, Paolo; Suryapranata, Harry; De Luca, Giuseppe

2016-06-01

Contrast-induced nephropathy is a common complication of procedures that are likely to use contrast media. The identification of high-risk patients and preventive optimal hydration are key measures to reduce the incidence of contrast-induced nephropathy. The aim of this study was to evaluate the role of the contrast volume to creatinine clearance ratio (V/CrCl) in the prediction of contrast-induced nephropathy after coronary angiography or percutaneous coronary intervention. Our population consisted of 2308 consecutive patients undergoing coronary angiography and/or percutaneous coronary intervention. The risk of contrast-induced nephropathy was evaluated across quartiles of the V/CrCl. Receiver operating characteristic curves were used to identify the best predictive value. Contrast-induced nephropathy was defined as an absolute increase of 0.5 mg/dL or a relative increase of >25% in creatinine levels 24-48 hours after the procedure. The total incidence of contrast-induced nephropathy was 12.2% and was significantly higher in the fourth quartile (first quartile 8.8%, second quartile 8.9%, third quartile 11.6% and fourth quartile 19.4%; P < 0.001). Using receiver operating characteristic curves we identified V/CrCl ≥ 6.15 as the best discriminant value for the prediction of contrast-induced nephropathy, which occurred in 25.1% of patients with V/CrCl ≥ 6.15 versus 9.7% in patients with V/CrCl < 6.15. These results were also confirmed at multivariate analysis after correction for all baseline confounders (adjusted odds ratio (AOR) (95% confidence interval (CI)) 1.81 (1.19-2.76); P = 0.005). The association between V/CrCl > 6.15 and an increased risk of contrast-induced nephropathy was confirmed among diabetic (11% vs. 27.7%; p P < 0.001) and non-diabetic patients (8.9% vs. 23%; Pp < 0.001), also after correction for all baseline confounders. This is one of the largest studies evaluating the association between the V/CrCl ratio and the risk of contrast-induced nephropathy in patients undergoing coronary angiography or percutaneous coronary intervention. We found that a V/CrCl ratio >6.15 was independently associated with an increased risk of contrast-induced nephropathy. © The European Society of Cardiology 2015.

Long-term Brain Tissue Monitoring after Semi-brain Irradiation in Rats Using Proton Magnetic Resonance Spectroscopy: A Preliminary Study In vivo

PubMed Central

Chen, Hong; Cheng, Yu-Shu; Zhou, Zheng-Rong

2017-01-01

Background: In head and neck neoplasm survivors treated with brain irradiation, metabolic alterations would occur in the radiation-induced injury area. The mechanism of these metabolic alterations has not been fully understood, while the alternations could be sensitively detected by proton (1H) nuclear magnetic resonance spectroscopy (MRS). In this study, we investigated the metabolic characteristics of radiation-induced brain injury through a long-term follow-up after radiation treatment using MRS in vivo. Methods: A total of 12 adult Sprague-Dawley rats received a single dose of 30 Gy radiation treatment to semi-brain (field size: 1.0 cm × 2.0 cm; anterior limit: binocular posterior inner canthus connection; posterior limit: external acoustic meatus connection; internal limit: sagittal suture). Conventional magnetic resonance imaging and single-voxel 1H-MRS were performed at different time points (in month 0 before irradiation as well as in the 1st, 3rd, 5th, 7th, and 9th months after irradiation) to investigate the alternations in irradiation field. N-acetylaspartate/choline (NAA/Cho), NAA/creatinine (Cr), and Cho/Cr ratios were measured in the bilateral hippocampus and quantitatively analyzed with a repeated-measures mixed-effects model and multiple comparison test. Results: Significant changes in the ratios of NAA/Cho (F = 57.37, Pg < 0.001), NAA/Cr (F = 54.49, Pg < 0.001), and Cho/Cr (F = 9.78, Pg = 0.005) between the hippocampus region of the irradiated semi-brain and the contralateral semi-brain were observed. There were significant differences in NAA/Cho (F = 9.17, Pt < 0.001) and NAA/Cr (F = 13.04, Pt < 0.001) ratios over time. The tendency of NAA/Cr to change with time showed no significant difference between the irradiated and contralateral sides. Nevertheless, there were significant differences in the Cho/Cr ratio between these two sides. Conclusions: MRS can sensitively detect metabolic alternations. Significant changes of metabolites ratio in the first few months after radiation treatment reflect the metabolic disturbance in the acute and early-delayed stages of radiation-induced brain injuries. PMID:28397726

The Preparation of Porous Sol-Gel Silica with Metal Organic Framework MIL-101(Cr) by Microwave-Assisted Hydrothermal Method for Adsorption Chillers

PubMed Central

Uma, Kasimayan; Pan, Guan-Ting; Yang, Thomas C.-K.

2017-01-01

Metal organic framework (MOF) of MIL-101(Cr)-Silica (SiO2) composites with highly mesoporous and uniform dispersions were synthesized by a microwave-assisted hydrothermal method followed by the sol-gel technique. Water vapor adsorption experiments were conducted on the MIL-101(Cr)-SiO2 composites for industrial adsorption chiller applications. The effects of MIL-101(Cr)-SiO2 mixing ratios (ranging from 0% to 52%), the surface area and amount of Lewis and Brønsted sites were comprehensively determined through water vapor adsorption experiments and the adsorption mechanism is also explained. The BET and Langmuir results indicate that the adsorption isotherms associated with the various MIL-101(Cr)-SiO2 ratios demonstrated Type I and IV adsorption behavior, due to the mesoporous structure of the MIL-101(Cr)-SiO2. It was observed that the increase in the amount of Lewis and Brønsted sites on the MIL-101(Cr)-SiO2 composites significantly improves the water vapor adsorption efficiency, for greater stability during the water vapor adsorption experiments. PMID:28772969

Feed-conversion ratio of finisher pigs in the USA.

PubMed

Losinger, W C

1998-10-09

Although the feed-conversion ratio is recognized as a prominent indicator of profitability for pork producers, only 212 (50.7%) of 418 producers who were asked the feed-conversion ratio for finisher pigs provided a response during the USA National Animal Health Monitoring System 1995 National Swine Study. Of these, 126 (59.4%) producers furnished a feed-conversion ratio which they characterized as having been calculated from records, while 86 (40.6%) gave a response that they characterized as estimated or guessed. Feed-conversion ratios ranged from 2.18 to 5.91 kg of feed fed for each kg of live-body weight gained during the grower/finisher phase, with a mean of 3.28 and a standard deviation of 0.52. Stepwise regression revealed the following management factors to be associated with improved feed-conversion ratios: > or = 3 different rations fed during the grower/finisher phase (P < 0.01); no rations mixed on the farm (P < 0.05); and not giving chlortetracycline in feed or water as a disease preventive or growth promotant (P < 0.01). In addition, operations where > or = 3000 pigs entered the grower/finisher-production phase during the six-month period prior to interview had a better mean feed-conversion ratio than operations where < 3000 pigs entered the grower/finisher phase (P < 0.01).

Size Distribution and Estimated Respiratory Deposition of Total Chromium, Hexavalent Chromium, Manganese, and Nickel in Gas Metal Arc Welding Fume Aerosols

PubMed Central

Cena, Lorenzo G.; Chisholm, William P.; Keane, Michael J.; Cumpston, Amy; Chen, Bean T.

2016-01-01

A laboratory study was conducted to determine the mass of total Cr, Cr(VI), Mn, and Ni in 15 size fractions for mild and stainless steel gas-metal arc welding (GMAW) fumes. Samples were collected using a nano multi orifice uniform deposition impactor (MOUDI) with polyvinyl chloride filters on each stage. The filters were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) and ion chromatography. Limits of detection (LODs) and quantitation (LOQs) were experimentally calculated and percent recoveries were measured from spiked metals in solution and dry, certified welding-fume reference material. The fraction of Cr(VI) in total Cr was estimated by calculating the ratio of Cr(VI) to total Cr mass for each particle size range. Expected, regional deposition of each metal was estimated according to respiratory-deposition models. The weight percent (standard deviation) of Mn in mild steel fumes was 9.2% (6.8%). For stainless steel fumes, the weight percentages were 8.4% (5.4%) for total Cr, 12.2% (6.5%) for Mn, 2.1% (1.5%) for Ni and 0.5% (0.4%) for Cr(VI). All metals presented a fraction between 0.04 and 0.6 μm. Total Cr and Ni presented an additional fraction <0.03 μm. On average 6% of the Cr was found in the Cr(VI) valence state. There was no statistical difference between the smallest and largest mean Cr(VI) to total Cr mass ratio (p-value D 0.19), hence our analysis does not show that particle size affects the contribution of Cr(VI) to total Cr. The predicted total respiratory deposition for the metal particles was ∼25%. The sites of principal deposition were the head airways (7–10%) and the alveolar region (11–14%). Estimated Cr(VI) deposition was highest in the alveolar region (14%). PMID:26848207

Size Distribution and Estimated Respiratory Deposition of Total Chromium, Hexavalent Chromium, Manganese, and Nickel in Gas Metal Arc Welding Fume Aerosols.

PubMed

Cena, Lorenzo G; Chisholm, William P; Keane, Michael J; Cumpston, Amy; Chen, Bean T

A laboratory study was conducted to determine the mass of total Cr, Cr(VI), Mn, and Ni in 15 size fractions for mild and stainless steel gas-metal arc welding (GMAW) fumes. Samples were collected using a nano multi orifice uniform deposition impactor (MOUDI) with polyvinyl chloride filters on each stage. The filters were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) and ion chromatography. Limits of detection (LODs) and quantitation (LOQs) were experimentally calculated and percent recoveries were measured from spiked metals in solution and dry, certified welding-fume reference material. The fraction of Cr(VI) in total Cr was estimated by calculating the ratio of Cr(VI) to total Cr mass for each particle size range. Expected, regional deposition of each metal was estimated according to respiratory-deposition models. The weight percent (standard deviation) of Mn in mild steel fumes was 9.2% (6.8%). For stainless steel fumes, the weight percentages were 8.4% (5.4%) for total Cr, 12.2% (6.5%) for Mn, 2.1% (1.5%) for Ni and 0.5% (0.4%) for Cr(VI). All metals presented a fraction between 0.04 and 0.6 μ m. Total Cr and Ni presented an additional fraction <0.03 μ m. On average 6% of the Cr was found in the Cr(VI) valence state. There was no statistical difference between the smallest and largest mean Cr(VI) to total Cr mass ratio ( p -value D 0.19), hence our analysis does not show that particle size affects the contribution of Cr(VI) to total Cr. The predicted total respiratory deposition for the metal particles was ∼25%. The sites of principal deposition were the head airways (7-10%) and the alveolar region (11-14%). Estimated Cr(VI) deposition was highest in the alveolar region (14%).

Differences in the direction of change of cerebral function parameters are evident over three years in HIV-infected individuals electively commencing initial cART.

PubMed

Winston, Alan; Puls, Rebekah; Kerr, Stephen J; Duncombe, Chris; Li, Patrick; Gill, John M; Ramautarsing, Reshmie; Taylor-Robinson, Simon D; Emery, Sean; Cooper, David A

2015-01-01

Changes in cerebral metabolite ratios (CMR) measured on 1H-MRS and changes in cognitive function (CF) are described in subjects commencing combination antiretroviral therapy (cART), although the dynamics of such changes are poorly understood. Neuroasymptomatic, HIV-infected subjects electively commencing cART were eligible. CMR were assessed in three anatomical voxels and CF assessed at baseline, week 48 and week 144. Overall differences in absolute change in CMRs and CF parameters between 0-48 and 48-144 weeks were assessed. Twenty-two subjects completed study procedures. Plasma HIV-RNA was <50 copies/mL in all at week 48 and in all, but two subjects at week 144. In general, between weeks 0-48 a rise in N-acetyl-aspartate(NAA)/Creatine(Cr) ratio and a decline in myo-Inositol(mI)/Cr ratio were observed. Between weeks 48-144, small rises in NAA/Cr ratio were observed in two anatomical voxels, whereas a rise in mI/Cr ratio was observed in all anatomical locations (0.31 (0.66) and -0.27 (1.35) between weeks 0-48 and 0.13 (0.91) and 1.13 (1.71) between weeks 48-144 for absolute changes in NAA/Cr and mI/Cr (SD) in frontal-grey voxel, respectively). Global CF score improved between weeks 0-48 and then declined between weeks 48-144 (0.63 (1.16) and -0.63 (0.1.41) for mean absolute change (SD) between weeks 0-48 and weeks 48-144, respectively). The direction of change of cerebral function parameters differs over time in HIV-infected subjects commencing cART, highlighting the need for long-term follow-up in such studies. The changes we have observed between weeks 48-144 may represent the initial development of cerebral toxicities from cART.

Regulation of organic nucleic acids and serum biochemistry parameters by dietary chromium picolinate supplementation in swine model.

PubMed

Jiajun, Yang; Aiyun, Han; Shanshan, Zheng; Minhong, Zhang

2011-04-01

The relationships between chromium and metabolism are sophisticated. Organic nucleic acids and serum biochemistry parameters are affected by dietary chromium levels. The objective of this work was to study the effect of chromium picolinate (CrPic) supplementation on total DNA and RNA contents, the ratio of RNA/DNA in muscle and in pancreatic tissue, the level of insulin receptor (IR) mRNA and some serum biochemistry parameters in a porcine model. Young animals (48) were assigned randomly into three groups of 16 piglets, fed with three different dietary levels of Cr (common basal feedstuff alone or supplemented with CrPic at a dose of 1.61 μg/g or 3.22 μg/g, which corresponds to 0.2 μg/g and 0.4 μg/g Cr). After 80 days, the animals were sacrificed and skeletal muscle and pancreatic tissues were analyzed to detect differences caused by different levels of dietary Cr. The total content of RNA in muscle was increased significantly (P<0.05) in the CrPic supplemented groups. There was no significant difference between groups in the concentrations of total RNA in the pancreas or DNA in the muscle and pancreatic tissues. The RNA/DNA ratio in pancreas showed no significant change but the ratio was increased significantly (P<0.05) in muscle. There was a slight increase of the mRNA level of IR but there was no significant difference between groups. The content of serum cholesterol and insulin were reduced significantly (P<0.05) in the CrPic-supplemented groups and the content of high-density lipoprotein cholesterol (HDLC) was increased significantly (P<0.05) as the CrPic dose increased. There was a slight (non-significant) reduction of the concentrations of serum triglyceride and low-density lipoprotein cholesterol (LDLC) in the CrPic supplementation groups. Supplementary CrPic caused no significant change of muscular mRNA level of IR in healthy animals. An increased content of RNA in muscle, improved cholesterol metabolism and improved insulin sensitivity were found in these CrPic-treated groups in the porcine model. Copyright © 2011 Elsevier GmbH. All rights reserved.

Using a Reminiscence-based Approach to Investigate the Cognitive Reserve of a Healthy Aging Population.

PubMed

Colombo, Barbara; Balzarotti, Stefania; Greenwood, Allison

2018-03-05

The concept of Cognitive Reserve (CR) has been used to account for brain plasticity in older adults that may underlie the resilience against the effects of aging or pathology on cognitive abilities. This study aims at exploring the proxies of CR in a sample of healthy older adults by analyzing their spontaneous reminiscence through a discourse analysis approach. Fifteen community-dwelling older adults were asked to participate in a video-recorded, spontaneous reminiscence interview. Interviews were transcribed according to Conversation Analysis, and two judges classified the interview content identifying five main markers of CR: enriched environment, cognitively stimulating activities, education, physical activity, and social interaction. Reminiscence allowed to identify markers of CR. Sharing stories that are linked to CR markers promote positive emotion, coherent sense of self, and cognitive evaluation of the importance of the social network. Reminisce looks like a possible approach not only to indirect evaluate the CR, but also to promote it. The reminisce approach can be used as a clinical tool to assess and increase the CR, help the clinical population to experience more positive emotions, maintain a more defined sense of self, and value more the social resources available.

Highly-efficient enzymatic conversion of crude algal oils into biodiesel.

PubMed

Wang, Yao; Liu, Jin; Gerken, Henri; Zhang, Chengwu; Hu, Qiang; Li, Yantao

2014-11-01

Energy-intensive chemical conversion of crude algal oils into biodiesel is a major barrier for cost-effective algal biofuel production. To overcome this problem, we developed an enzyme-based platform for conversion of crude algal oils into fatty acid methyl esters. Crude algal oils were extracted from the oleaginous microalga Nannochloropsis oceanica IMET1 and converted by an immobilized lipase from Candida antarctica. The effects of different acyl acceptors, t-butanol as a co-solvent, oil to t-butanol ratio, oil to methanol ratio, temperature and reaction time on biodiesel conversion efficiency were studied. The conversion efficiency reached 99.1% when the conversion conditions were optimized, i.e., an oil to t-butanol weight ratio of 1:1, an oil to methanol molar ratio of 1:12, and a reaction time of 4h at 25°C. The enzymatic conversion process developed in this study may hold a promise for low energy consumption, low wastewater-discharge biochemical conversion of algal feedstocks into biofuels. Published by Elsevier Ltd.

First-principles study on the structure, elastic properties, hardness and electronic structure of TMB4 (TM=Cr, Re, Ru and Os) compounds

NASA Astrophysics Data System (ADS)

Pan, Y.; Zheng, W. T.; Guan, W. M.; Zhang, K. H.; Fan, X. F.

2013-11-01

The structural formation, elastic properties, hardness and electronic structure of TMB4 (TM=Cr, Re, Ru and Os) compounds are investigated using first-principles approach. The value of C22 for these compounds is almost two times bigger than the C11 and C33. The intrinsic hardness, shear modulus and Young's modulus are calculated to be in a sequence of CrB4>ReB4>RuB4>OsB4, and the Poisson's ratio and B/G ratio of TMB4 follow the order of CrB4

[Effect of anshen jielu recipe in intervening cerebral metabolism in rats with generalized anxiety disorder using magnetic resonance spectroscopy].

PubMed

Tang, Qi-sheng; Li, Ning; Luo, Bin

2011-01-01

To study the metabolic change in brain of rats with generalized anxiety disorder (GAD) and the intervention effect with Anshen Jielu Recipe (AJR) on it. Eight rats selected from 32 Wistar rats as normal group, the others were established as GAD model by using uncertainty empty water bottles method. Then the GAD rats were randomly divided into the model group (saline, by gastrogavage), the control group [buspirone hydrochloride, 2.0 mg/(kg x d), by gastrogavage], the treatment group [AJR, 12.5 g/(kg x d), by gastrogavage], 8 in each group, all were treated for 7 days. The concentration of cerebral metabolites, including N-acetyl aspartate (NAA), choline (Cho), creatine (Cr) and glutamate (Glu), in bilateral prefrontal cortex and hippocampus were measured using high-field strong super-conductivity (7.0T) animal MRI; and the ratio of NAA/Cr, Cho/Cr and Glu/Cr were calculated. The effect of AJR intervention was evaluated by changes of MRI before and after rats being treated with AJR for 7 days. Rats with GAD showed lowered ratios of NAA/Cr and Cho/Cr, and elevated Glu/Cr ratio in the right prefrontal cortex than those in normal rats. After AJR intervention, the abnormal changes in the three indices were restored to certain extents. AJR has apparent antianxiety effect in rats with GAD, with the effect initiation faster than that in the control group. Its mechanism is probably correlated with the regulation of abnormal metabolism in the brain.

Compound-specific carbon, nitrogen, and hydrogen isotopic ratios for amino acids in CM and CR chondrites and their use in evaluating potential formation pathways

NASA Astrophysics Data System (ADS)

Elsila, Jamie E.; Charnley, Steven B.; Burton, Aaron S.; Glavin, Daniel P.; Dworkin, Jason P.

2012-09-01

Stable hydrogen, carbon, and nitrogen isotopic ratios (δD, δ13C, and δ15N) of organic compounds can reveal information about their origin and formation pathways. Several formation mechanisms and environments have been postulated for the amino acids detected in carbonaceous chondrites. As each proposed mechanism utilizes different precursor molecules, the isotopic signatures of the resulting amino acids may indicate the most likely of these pathways. We have applied gas chromatography with mass spectrometry and combustion isotope ratio mass spectrometry to measure the compound-specific C, N, and H stable isotopic ratios of amino acids from seven CM and CR carbonaceous chondrites: CM1/2 Allan Hills (ALH) 83100, CM2 Murchison, CM2 Lewis Cliff (LEW) 90500, CM2 Lonewolf Nunataks (LON) 94101, CR2 Graves Nunataks (GRA) 95229, CR2 Elephant Moraine (EET) 92042, and CR3 Queen Alexandra Range (QUE) 99177. We compare the isotopic compositions of amino acids in these meteorites with predictions of expected isotopic enrichments from potential formation pathways. We observe trends of decreasing δ13C and increasing δD with increasing carbon number in the α-H, α-NH2 amino acids that correspond to predictions made for formation via Strecker-cyanohydrin synthesis. We also observe light δ13C signatures for β-alanine, which may indicate either formation via Michael addition or via a pathway that forms primarily small, straight-chain, amine-terminal amino acids (n-ω-amino acids). Higher deuterium enrichments are observed in α-methyl amino acids, indicating formation of these amino acids or their precursors in cold interstellar or nebular environments. Finally, individual amino acids are more enriched in deuterium in CR chondrites than in CM chondrites, reflecting different parent-body chemistry.

Postictal in situ MRS brain lactate in the rat kindling model.

PubMed

Maton, B M; Najm, I M; Wang, Y; Lüders, H O; Ng, T C

1999-12-10

To determine the temporal and spatial extent of the lactate (Lact) changes as correlated with seizure characteristics and EEG changes in the rat kindling model. Prior studies using MRS have detected cerebral Lact postictally in animal models of seizures and in patients with intractable focal epilepsy. We performed MRS in sham control rats (n = 4) and in rats stimulated in the right hippocampus at two different stages of the kindling and at three time points after the seizures: <2 hours (n = 8 and 5, stage 0 and stage 5), 2 to 3 hours (n = 5 and 6), and >3 hours (n = 4 and 2). Lact/creatine (Cr) and N-acetylaspartate (NAA)/Cr ratios were measured in six contiguous voxels (three left, three right) covering the hippocampi, anterior and posterior regions, and compared with EEG and ictal behavior. Lact/Cr ratios were measured at a very low level in the sham control rats and in the >3-hour group. In the <2-hour group, Lact/Cr increase was higher in stage-5 rats as compared with stage-0 rats (p = 0.001, unpaired t-test) and sham control rats when all the voxels were considered. Lact/Cr ratios were higher in the stimulated area as compared with all other brain areas in stage-0 rats (p = 0.05, paired t-test) but not in the stage-5 rats. Similar results with more inter-animal variability were measured in the 2- to 3-hour group. NAA/Cr ratios increased significantly after stage-0 kindling in the stimulated hippocampus but not after stage-5 kindling. Postictal Lact increase as assayed by MRS correlates with EEG and behavioral seizures and suggests that it would be an additional noninvasive technique for seizure localization during the presurgical evaluation of patients with intractable focal epilepsy.

Chromium genotoxicity: a double-edged sword

PubMed Central

Nickens, Kristen P.; Patierno, Steven R.; Ceryak, Susan

2010-01-01

Certain forms of hexavalent chromium [Cr(VI)] are known respiratory carcinogens that induce a broad spectrum of DNA damage. Cr(VI)-carcinogenesis may be initiated or promoted through several mechanistic processes including, the intracellular metabolic reduction of Cr(VI) producing chromium species capable of interacting with DNA to yield genotoxic and mutagenic effects, Cr(VI)-induced inflammatory/immunological responses, and alteration of survival signaling pathways. Cr(VI) enters the cell through nonspecific anion channels, and is metabolically reduced by agents including ascorbate, glutathione, and cysteine to Cr(V), Cr(IV), and Cr(III). Cr(III) has a weak membrane permeability capacity and is unable to cross the cell membrane, thereby trapping it within the cell where it can bind to DNA and produce genetic damage leading to genomic instability. Structural genetic lesions produced by the intracellular reduction of Cr(VI) include DNA adducts, DNA strand breaks, DNA-protein crosslinks, oxidized bases, abasic sites, and DNA inter- and intrastrand crosslinks. The damage induced by Cr(VI) can lead to dysfunctional DNA replication and transcription, aberrant cell cycle checkpoints, dysregulated DNA repair mechanisms, microsatelite instability, inflammatory responses, and the disruption of key regulatory gene networks responsible for the balance of cell survival and cell death, which may all play an important role in Cr(VI) carcinogenesis. Several lines of evidence have indicated that neoplastic progression is a result of consecutive genetic/epigenetic changes that provide cellular survival advantages, and ultimately lead to the conversion of normal human cells to malignant cancer cells. This review is based on studies that provide a glimpse into Cr(VI) carcinogenicity via mechanisms including Cr(VI)-induced death-resistance, the involvement of DNA repair mechanisms in survival after chromium exposure, and the activation of survival signaling cascades in response to Cr(VI) genotoxicity. PMID:20430016

Decreased Urinary Sodium-to-urinary Creatinine Ratio Identifies Sodium Depletion in Pediatric Acute Gastroenteritis.

PubMed

Heinz-Erian, P; Akdar, Z; Haerter, B; Waldegger, S; Giner, T; Scholl-Bürgi, S; Mueller, T

2016-01-01

In acute gastroenteritis (AG) fecal losses may cause depletion of sodium (NaD) which may not be recognized because of normal plasma Na (pNa) concentrations. We studied the incidence of this state of normonatremic sodium depletion (NNaD) and the suitability of the urinary Na/urinary creatinine ratio (uNa/uCr) for diagnosing NNaD. 16 AG- and 16 healthy control children aged 0.8-15.0 years. Prospective cross sectional pilot study. Measurements of Na, K and creatinine in plasma (p) and urine (u). Calculation of uNa/uCr Ratio, fractional excretion of Na (FENa) and uNa/uK ratio as the hitherto best known parameters of prerenal Na depletion, respectively. pNa concentrations were normal in 15/16 AG patients (93.8%) with only one subnormal value of 133 mmol/L, and a mean value of 137.9±2.3 mmol/L not different from the normal control group (139.4±2.2 mmol/L). Also, mean uNa concentrations and uNa/uK ratios did not differ between both groups. However, uNa/uCr ratios were below normal in 13/16 AG children (81.3%) but normal in all healthy controls with a significantly lower mean value in the AG group (12.6±8.8 vs. 31.2±8.3 mmol/mmol; p<0.0001). Similarly, 14/16 AG patients (87.5%) had a decreased FENa<0.5% with a mean FENa value significantly lower than in controls (0.36±0.28% vs. 0.95±0.26%, p<0.0001). The good agreement between FENa and uNa/uCr results was also reflected by a high correlation coefficient of r=0.9333. The majority of AG patients was found to have NNaD as determined by uNa/uCr and FENa. Calculation of uNa/uCr may be useful for diagnosing NNaD in AG. © Georg Thieme Verlag KG Stuttgart · New York.

Nanoscale in-depth modification of CrOSi layers

NASA Astrophysics Data System (ADS)

Bertóti, I.; Tóth, A.; Mohai, M.; Kelly, R.; Marletta, G.; Farkas-Jahnke, M.

1997-02-01

In-depth modification of CrOSi layers on a nanoscale has been performed by low energy inert (Ar +, He +) and reactive (N 2+) ions. Chemical and short range structural investigations were done by XPS. Cr and Si were essentially oxidised in the as-prepared (i.e. virgin) samples. Ar + bombardment led to a nearly complete reduction of Cr to Cr 0. At the same time, about one third of the oxidised Si was converted to Si 0, which was shown to form SiCr bonds. Also, silicide type clusters, predicted earlier by XPS, have been identified by glancing angle electron diffraction. He + bombardment led to an increase of the surface O concentration. This was manifested also in the disruption of SiCr bonds formed by the preceding Ar + bombardment and conversion of Cr and Si predominantly to Cr 3+O, Cr 6+O and Si 4+O. With N 2+ bombardment formation of CrN and SiN bonds was observed. The thickness of the transformed surface layers were about 5 nm, 9 nm and 30 nm for Ar, N and He projectiles as estimated by TRIM calculations. The observed transformations were interpreted in terms of the relative importance of sputtering or ion induced mixing for Ar + and He +, and also by the role of thermodynamic driving forces.

Population Pharmacokinetics and Pharmacodynamics of Levofloxacin in Acutely Hospitalized Older Patients with Various Degrees of Renal Function

PubMed Central

Cojutti, Pier Giorgio; Ramos-Martin, Virginia; Schiavon, Isabella; Rossi, Paolo; Baraldo, Massimo; Hope, William

2016-01-01

ABSTRACT A retrospective study was conducted in a large sample of acutely hospitalized older patients who underwent therapeutic drug monitoring during levofloxacin treatment. The aim was to assess the population pharmacokinetics (popPK) and pharmacodynamics of levofloxacin among older patients. PopPK and Monte Carlo simulation were performed to define the permissible doses in older patients according to various degrees of renal function. Classification and regression tree (CART) analysis was used to detect the cutoff 24-hour area under the concentration-time curve (AUC24)/MIC ratio that best correlated with the clinical outcome. The probability of target attainment (PTA) of this value was calculated against different pathogens. A total of 168 patients were included, and 330 trough and 239 peak concentrations were used for the popPK analysis. Creatinine clearance (CrCL) was the only covariate that improved the model fit (levofloxacin CL = 0.399 + 0.051 × CrCLCKD-EPI [creatinine clearance estimated by means of the chronic kidney disease epidemiology]). Drug doses ranged between 500 mg every 48 h and 500 mg every 12 h in relation to different renal functions. The identified cutoff AUC24/MIC ratio (≥95.7) was the only covariate that correlated with a favorable clinical outcome in multivariate regression analysis (odds ratio [OR], 20.85; 95% confidence interval [CI], 1.56 to 186.73). PTAs were optimal (>80%) against Escherichia coli and Haemophilus influenzae, borderline against Staphylococcus aureus, and suboptimal against Pseudomonas aeruginosa. The levofloxacin doses defined in our study may be effective for the treatment of infections due to bacterial pathogens, with an MIC of ≤0.5 mg/liter in older patients with various degrees of renal function, while minimizing the toxicity risk. Conversely, the addition of another active antimicrobial should be considered whenever treating infections caused by less susceptible pathogens. PMID:28031199

Chronic intermittent but not constant hypoxia decreases NAA/Cr ratios in neonatal mouse hippocampus and thalamus.

PubMed

Douglas, Robert M; Miyasaka, Naoyuki; Takahashi, Kan; Latuszek-Barrantes, Adrianna; Haddad, Gabriel G; Hetherington, Hoby P

2007-03-01

Chronic constant hypoxia (CCH) and chronic intermittent hypoxia (CIH) are known to have deleterious effects on the central nervous system. Because of the difference in the pattern of hypoxic exposure, it is possible that the pathological outcome would vary. The N-acetyl aspartate/creatine (NAA/Cr) ratio is a reliable marker of neuronal integrity, and this can be noninvasively measured by proton nuclear magnetic resonance spectroscopy. P2 CD1 mouse pups with their dams were exposed to either CCH, where the Fi(O(2)) was maintained at 11% continuously or to CIH, where the Fi(O(2)) was varied between 21 and 11% every 4 min. P30 mice exposed to intermittent hypoxia for 4 wk demonstrated a significant decrease in the NAA/Cr ratio in the hippocampus and thalamus, which was reversed by a subsequent exposure to 4 wk of normoxia. Meanwhile, mice exposed to 4 wk of constant hypoxia did not demonstrate any differences in their NAA/Cr ratios from controls in these brain regions. These results indicate that an intermittent pattern of hypoxic exposure may have a more adverse effect on neuronal function and integrity than a continuous one. The reversal of NAA/Cr levels to baseline during the return to normoxia indicates that therapeutic strategies targeted at alleviating the intermittent hypoxic stress in diseases, such as obstructive sleep apnea, have the potential for inducing significant neurocognitive recovery in these patients.

Higher visceral fat is associated with lower cerebral N-acetyl-aspartate ratios in middle-aged adults.

PubMed

Kaur, Sonya; Birdsill, Alex C; Steward, Kayla; Pasha, Evan; Kruzliak, Peter; Tanaka, Hirofumi; Haley, Andreana P

2017-06-01

Excessive adipose tissue, particularly with a central distribution, consists of visceral fat, which is metabolically active and could impinge upon central nervous system functioning. The aim of the current study was to examine levels of visceral adiposity in relation to key cerebral metabolite ratios localized in the occipitoparietal grey matter. Seventy-three adults, aged between 40 and 60 years, underwent structural magnetic resonance imaging and single voxel 1 H Magnetic Resonance Spectroscopy ( 1 H MRS). Visceral fat was assessed using Dual Energy X Ray Absorptiometry (DXA). Individuals with higher visceral fat mass and volume had significantly lower ratios of N-acetyl-aspartate to total creatine (phosphocreatine + creatine, PCr + Cr) (NAA/PCr + Cr) (β = -0.29, p = 0.03, β = -0.28, p = 0.04). They also had significantly higher ratios of myo-inositol to total creatine (mI/PCr + Cr ) (β = 0.36, p = 0.01, β = 0.36, p = 0.01). Visceral fat mass and volume were not significantly related to ratios of glutamate to total creatine (Glu/PCr + Cr). While future studies are necessary, these results indicate central adiposity is associated with metabolic changes that could impinge upon the central nervous system in middle age.

[Clinical Significance of Urinary Microalbumin to Creatinine Ratio in Physical Examinations].

PubMed

Guo, Qin; Luo, Wei; Yin, Dai-shu; Jia, Cheng-yao

2016-01-01

To-determine the association between urinary microalbumin to creatinine ratio (mALB/Cr) and metabolic indicators in people undergoing physical examinations. A total of 4 184 people who took physical examinations in West China Hospital, Sichuan University from November 2013 to October 2014 participated in this study. We measured their body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), waistline, hipline, Waist-to-hip ratio (WHR), urinary mALB/Cr, serum glucose (GLU), total cholesterol (TC), triglyceride (TG) , high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), blood urea nitrogen (BUN), serum creatinine (SCr) , uric acid (UA), cystatin C (Cys-C), glomerular filtration rate (eGFR) and homocysteine (Hcy). (1) The participants had a median (interquartile range) mALB/Cr of 5.7 (3.1-11.8) mg/g: 5.4 (3.0-11.3) mg/g for males and 6.3 (3.6-13.2) mg/g for females (P < 0.05). (2) About 10.95% participants (10.96% for males and 10.90% for females) had a mALB/Cr ≥ 30 mg/g. (3) mALB/Cr increased with age. (4) BMI, SBP, DBP, waistline, WHR, GLU, HDL-C, TG, SCr, BUN, UA, eGFR and Cys-C were associated the distribution of participants (P < 0.05) across the three groups of mALB/Cr: normal (< 30 mg/g), microalbuminuria (30-300 mg/g) , and proteinuria (> 300 mg/g). (5) Logistic regression demonstrated that age, SBP, WHR, GLU, TG and eGFR were significant predictors of albuminuria. A high level of abnormal/positive mALB/Cr was found in people undergoing physical examinations. Increased age, SBP, WHR, GLU, TG and decreased eGFR are major risk factors of abnormal mALB/Cr. mALB/Cr should be monitored, especially in the elderly and those with high-metabolic-syndrome.

Conversion from film to image plates for transfer method neutron radiography of nuclear fuel

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

Craft, Aaron E.; Papaioannou, Glen C.; Chichester, David L.

This paper summarizes efforts to characterize and qualify a computed radiography (CR) system for neutron radiography of irradiated nuclear fuel at Idaho National Laboratory (INL). INL has multiple programs that are actively developing, testing, and evaluating new nuclear fuels. Irradiated fuel experiments are subjected to a number of sequential post-irradiation examination techniques that provide insight into the overall behavior and performance of the fuel. One of the first and most important of these exams is neutron radiography, which provides more comprehensive information about the internal condition of irradiated nuclear fuel than any other non-destructive technique to date. Results from neutronmore » radiography are often the driver for subsequent examinations of the PIE program. Features of interest that can be evaluated using neutron radiography include irradiation-induced swelling, isotopic and fuel-fragment redistribution, plate deformations, and fuel fracturing. The NRAD currently uses the foil-film transfer technique with film for imaging fuel. INL is pursuing multiple efforts to advance its neutron imaging capabilities for evaluating irradiated fuel and other applications, including conversion from film to CR image plates. Neutron CR is the current state-of-the-art for neutron imaging of highly-radioactive objects. Initial neutron radiographs of various types of nuclear fuel indicate that radiographs can be obtained of comparable image quality currently obtained using film. This paper provides neutron radiographs of representative irradiated fuel pins along with neutron radiographs of standards that informed the qualification of the neutron CR system for routine use. Additionally, this paper includes evaluations of some of the CR scanner parameters and their effects on image quality.« less

Impact of fibre intake and fibre source on digestibility, gut development, retention time and growth performance of indigenous and exotic pigs.

PubMed

Ngoc, T T B; Len, N T; Lindberg, J E

2013-05-01

The impact of fibre level and fibre source on digestibility, gastrointestinal tract (GIT) development, total tract mean retention time (MRT) and growth performance was studied in indigenous Mong Cai (MC) and exotic Landrace × Yorkshire (LY) pigs. The diets were based on maize, rice bran, soyabean meal, fish meal and soyabean oil, and cassava residue (CR) or brewer's grain (BG) as fibrous ingredient sources in the high-fibre diets (HF) and were fed ad libitum. A low-fibre diet (LF), containing around 200 g NDF/kg dry matter (DM), was formulated without CR and BG as feed ingredients. The HF diets (HF-CR and HF-BG) were formulated to contain around 270 g NDF/kg DM. The experiment was arranged as a 2 × 3 factorial completely randomized design with six replications, and lasted 27 days. Increased dietary fibre level resulted in a reduction (P < 0.05) in average daily gain, digestibility of organic matter (OM), CP and gross energy (GE) at the ileum and in the total tract, and in MRT, and an increase (P < 0.05) in the feed conversion ratio and in the weight of the GIT (except for small intestine and caecum). The coefficients of total tract digestibility of fibre fractions were higher in HF diets than in the LF diet, with highest values for diet HF-CR, which had a high proportion of soluble non-starch polysaccharides. MC pigs had longer MRT of digesta than LY pigs (P < 0.05), resulting in higher digestibility at the ileum and in the total tract. Across diets and breeds, the total tract apparent digestibility of OM, CP and GE was positively related (R 2 = 0.80 to 0.84) to the MRT of solids, whereas the MRT was negatively related to the DM intake (R 2 = 0.60).

Studies of redox active silicalite-2 and the development of stable white-light phosphors

NASA Astrophysics Data System (ADS)

Lita, Adrian

Mn-silicalite-2 was synthesized at high pH using the molecular cluster, Mn12O12(O2CCH3)16 as a Mn Source. No precipitation of manganese hydroxide was observed with this cluster even with the use of tetrabutylammonium hydroxide as a templating agent. This synthetic approach resulted in the incorporation of up to 2.5 mol % Mn into the silicalite-2 with direct substitution into the framework verified by a linear relationship between unit cell volume and loading. The Mn is reduced to Mn(II) during hydrothermal synthesis and incorporated into the silicalite-2 framework during calcination at 500°C. Further calcination at 750°C does not affect the crystallinity but oxidizes essentially all of the Mn(II) to Mn(III). Cr(IV) substituted silicalite-2 was generated by reduction of Cr(VI)-silicalite-2 lattice sites at in a CO atmosphere. The reduction process, Reduction at high pressures was found to give almost complete conversion of the Cr(VI) sites to Cr(IV). As generated, the Cr(IV) sites do not reoxidize to Cr(VI) under ambient conditions or in the presence of oxidants under reaction conditions. We report the development of new class solid-state white-light phosphors based on stable nanoparticle-silica glass composites. These materials are made from the incorporating of CdSe nanoparticles into a silica Sol-gel solution. Once it gelled and aged the materials are calcined at 500°C under oxygen. The solid that results are robust with a bright white luminescence (20%) under UV excitation that gives virtually pure white light with coordinates of (0.34, 0.36) on the CIE 1931 chromaticity diagram and, more importantly, the emission envelope coincides nearly identically with the scotopic eye response function. The white-light phosphors have a scotopic/phtopic ratio of 2.56, indicating that these phosphors will be perceived as a particularly efficient illumination source in a dark environment thereby being more energy efficient. The emission comes from a distribution of nanoscale CdSe particles, with size-polydispersity brought on by calcination and subsequent fusing of nanoparticle agglomerates in the micropores of the silica xerogel. The silica matrix makes them exceedingly robust, with no changes in the emission properties observed for periods in excess of 18 months.

Chlorophyll a is a favorable substrate for Chlamydomonas Mg-dechelatase encoded by STAY-GREEN.

PubMed

Matsuda, Kaori; Shimoda, Yousuke; Tanaka, Ayumi; Ito, Hisashi

2016-12-01

Mg removal from chlorophyll by Mg-dechelatase is the first step of chlorophyll degradation. Recent studies showed that in Arabidopsis, Stay Green (SGR) encodes Mg-dechelatase. Though the Escherichia coli expression system is advantageous for investigating the properties of Mg-dechelatase, Arabidopsis Mg-dechelatase is not successfully expressed in E. coli. Chlamydomonas reinhardtii SGR (CrSGR) has a long, hydrophilic tail, suggesting that active CrSGR can be expressed in E. coli. After the incubation of chlorophyll a with CrSGR expressed in E. coli, pheophytin a accumulated, indicating that active CrSGR was expressed in E. coli. Substrate specificity of CrSGR against chlorophyll b and an intermediate molecule of the chlorophyll b degradation pathway was examined. CrSGR exhibited no activity against chlorophyll b and low activity against 7-hydroxymethyl chlorophyll a, consistent with the fact that chlorophyll b is degraded only after conversion to chlorophyll a. CrSGR exhibited low activity against divinyl chlorophyll a and chlorophyll a', and no activity against chlorophyllide a, protochlorophyll a, chlorophyll c 2 , and Zn-chlorophyll a. These observations indicate that chlorophyll a is the most favorable substrate for CrSGR. When CrSGR was expressed in Arabidopsis cells, the chlorophyll content decreased, further confirming that SGR has Mg-dechelating activity in chloroplasts. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Catalytic role of Cu(II) in the reduction of Cr(VI) by citric acid under an irradiation of simulated solar light.

PubMed

Li, Ying; Chen, Cheng; Zhang, Jing; Lan, Yeqing

2015-05-01

The catalytic role of Cu(II) in the reduction of Cr(VI) by citric acid with simulated solar light was investigated. The results demonstrated that Cu(II) could significantly accelerate Cr(VI) reduction and the reaction obeyed to pseudo zero-order kinetics with respect to Cr(VI). The removal of Cr(VI) was related to the initial concentrations of Cu(II), citric acid, and the types of organic acids. The optimal removal of Cr(VI) was achieved at pH 4, and the rates of Cu(II) photocatalytic reduction of Cr(VI) by organic acids were in the order: tartaric acid (two α-OH groups, two -COOH groups)>citric acid (one α-OH group, three -COOH groups)>malic acid (one α-OH group, two -COOH groups)>lactic acid (one α-OH group, one -COOH group)≫succinic acid (two -COOH groups), suggesting that the number of α-OH was the key factor for the reaction, followed by the number of -COOH. The formation of Cu(II)-citric acid complex could generate Cu(I) and radicals through a pathway of metal-ligand-electron transfer, promoting the reduction of Cr(VI). This study is helpful to fully understanding the conversion of Cr(VI) in the existence of both organic acids and Cu(II) with solar light in aquatic environments. Copyright © 2015 Elsevier Ltd. All rights reserved.

Femtosecond Cr:LiSAF and Cr:LiCAF lasers pumped by tapered diode lasers.

PubMed

Demirbas, Umit; Schmalz, Michael; Sumpf, Bernd; Erbert, Götz; Petrich, Gale S; Kolodziejski, Leslie A; Fujimoto, James G; Kärtner, Franz X; Leitenstorfer, Alfred

2011-10-10

We report compact, low-cost and efficient Cr:Colquiriite lasers that are pumped by high brightness tapered laser diodes. The tapered laser diodes provided 1 to 1.2 W of output power around 675 nm, at an electrical-to-optical conversion efficiency of about 30%. Using a single tapered diode laser as the pump source, we have demonstrated output powers of 500 mW and 410 mW together with slope efficiencies of 47% and 41% from continuous wave (cw) Cr:LiSAF and Cr:LiCAF lasers, respectively. In cw mode-locked operation, sub-100-fs pulse trains with average power between 200 mW and 250 mW were obtained at repetition rates around 100 MHz. Upon pumping the Cr:Colquiriite lasers with two tapered laser diodes (one from each side of the crystal), we have observed scaling of cw powers to 850 mW in Cr:LiSAF and to 650 mW in Cr:LiCAF. From the double side pumped Cr:LiCAF laser, we have also obtained ~220 fs long pulses with 5.4 nJ of pulse energy at 77 MHz repetition rate. These are the highest energy levels reported from Cr:Colquiriite so far at these repetition rates. Our findings indicate that tapered diodes in the red spectral region are likely to become the standard pump source for Cr:Colquiriite lasers in the near future. Moreover, the simplified pumping scheme might facilitate efficient commercialization of Cr:Colquiriite systems, bearing the potential to significantly boost applications of cw and femtosecond lasers in this spectral region (750-1000 nm).

Magnetic resonance spectroscopy in mild cognitive impairment: systematic review and meta-analysis.

PubMed

Tumati, Shankar; Martens, Sander; Aleman, André

2013-12-01

Research using proton magnetic resonance spectroscopy (MRS) can potentially elucidate metabolite changes representing early degeneration in Mild Cognitive Impairment (MCI), an early stage of dementia. We integrated the published literature using meta-analysis to identify patterns of metabolite changes in MCI. 29 MRS studies (with a total of 607 MCI patients and 862 healthy controls) were classified according to brain regions. Hedges' g was used as effect size in a random effects model. N-Acetyl Aspartate (NAA) measures were consistently reduced in posterior cingulate (PC), hippocampus, and the paratrigonal white matter (PWM). Creatine (Cr) concentration was reduced in the hippocampus and PWM. Choline (Cho) concentration was reduced in the hippocampus while Cho/Cr ratio was raised in the PC. Myo-inositol (mI) concentration was raised in the PC and mI/Cr ratio was raised in the hippocampus. NAA/mI ratio was reduced in the PC. NAA may be the most reliable marker of brain dysfunction in MCI though mI, Cho, and Cr may also contribute towards this. Copyright © 2013 Elsevier Ltd. All rights reserved.

High-precision QEC values of superallowed 0+ → 0+β-emitters 46Cr, 50Fe and 54Ni

NASA Astrophysics Data System (ADS)

Zhang, P.; Xu, X.; Shuai, P.; Chen, R. J.; Yan, X. L.; Zhang, Y. H.; Wang, M.; Litvinov, Yu. A.; Blaum, K.; Xu, H. S.; Bao, T.; Chen, X. C.; Chen, H.; Fu, C. Y.; He, J. J.; Kubono, S.; Lam, Y. H.; Liu, D. W.; Mao, R. S.; Ma, X. W.; Sun, M. Z.; Tu, X. L.; Xing, Y. M.; Yang, J. C.; Yuan, Y. J.; Zeng, Q.; Zhou, X.; Zhou, X. H.; Zhan, W. L.; Litvinov, S.; Audi, G.; Uesaka, T.; Yamaguchi, Y.; Yamaguchi, T.; Ozawa, A.; Sun, B. H.; Sun, Y.; Xu, F. R.

2017-04-01

Short-lived 46Cr, 50Fe and 54Ni were studied by isochronous mass spectrometry at the HIRFL-CSR facility in Lanzhou. The measured precision mass excesses (ME) of 46Cr, 50Fe and 54Ni are - 29471 (11) keV, - 34477 (6) keV and - 39278 (4) keV, respectively. The superallowed 0+ →0+β-decay Q values were derived to be QEC (46Cr) = 7604 (11) keV, QEC (50Fe) = 8150 (6) keV and QEC (54Ni) = 8731 (4) keV. The values for 50Fe and 54Ni are by one order of magnitude more precise than the adopted literature values. By combining the existing half-lives and branching ratios, we obtained the corrected Ft values to be Ft (50Fe) = 3103 (70) s and Ft (54Ni) = 3076 (50) s. The main contribution to the Ft uncertainties is now due to β-decay branching ratios, still, more high-precision measurements of the half-lives, the masses, and especially the branching ratios are needed in order to satisfy the requirements for a stringent CVC test.

Synthesis of Bi nanowire networks and their superior photocatalytic activity for Cr(vi) reduction.

PubMed

Zhao, Jin; Han, Qiaofeng; Zhu, Junwu; Wu, Xiaodong; Wang, Xin

2014-09-07

Interconnected Bi nanowire networks were synthesized for the first time via a solvothermal route by using ethylene glycol (EG) as both a solvent and a reducing agent, and citric acid (CA) as a stabilizing agent at a molar ratio of CA/Bi(3+) = 5. Among various reaction conditions including the temperature, reaction time and precursor concentration, the molar ratio of CA/Bi(3+) was the dominant experimental parameter to influence the morphology and structures of the Bi crystals. Highly dispersed Bi microspheres and network-like Bi thick wires were obtained if the molar ratio of CA/Bi(3+) was changed to 2.5 and 10, respectively. As compared to other additives including trisodium citrate, cetyltrimethylammonium bromide (CTAB) and oxalic acid, good solubility of CA in EG together with its coordination effect played a crucial role in the formation of network-like Bi nanowires. The Bi nanowire networks exhibited excellent photocatalytic performance for Cr(vi) reduction. Cr(vi) was completely reduced to less toxic Cr(iii) after 8 min and 55 min of UV and visible-light irradiation, respectively.

Pressure effects on structural, electronic, elastic and lattice dynamical properties of XSi2 (X = Cr, Mo, W) from first principles

NASA Astrophysics Data System (ADS)

Zhu, Haiyan; Shi, Liwei; Li, Shuaiqi; Zhang, Shaobo; Xia, Wangsuo

2018-04-01

First-principles calculations have been performed to study the structure, elastic and lattice dynamical properties of C40 XSi2 (X=Cr, Mo, W) under hydrostatic pressure. The obtained structural parameters are in line with existing experimental and theoretical data. The evolutions of fundamental bandgap energies, elastic moduli, IR absorption spectra with pressure have been investigated in detail. Our results indicate that the energy gaps of XSi2 (X=Cr, Mo, W) show different trends as the pressure increases. Larger BH/GH ratio and Poisson’s ratio are achieved with pressure, suggesting an improved ductility for XSi2 (X=Cr, Mo, W). Moreover, a large elastic anisotropy under pressure is exhibited in Young’s anisotropic factors. The infrared-active phonon frequencies exhibit substantial blueshifts under pressure.

Single voxel magnetic resonance spectroscopy at 3 Tesla in a memory disorders clinic: early right hippocampal NAA/Cr loss in mildly impaired subjects.

PubMed

Caserta, Maria T; Ragin, Ann; Hermida, Adriana P; Ahrens, R John; Wise, Leon

2008-11-30

In this study, we use magnetic resonance spectroscopy (MRS) at 3 Tesla to measure N-acetyl aspartate (NAA), myo-inositol (mI) and choline (Cho) to creatine (Cr) ratios in R (right) and L (left) hippocampi (H) in 8 mildly memory impaired (MMI), 6 probable Alzheimer's Disease (PRAD), and 17 control subjects. NAA/Cr was significantly reduced in the RH in the MMI group and bilaterally in the PRAD group vs. controls. No other metabolite differences were noted between the three groups. Five MMI subjects have converted to PRAD in follow-up. These findings suggest that RH NAA/Cr ratios measured at 3 Tesla may be a sensitive marker of future progression to dementia in a clinically defined population with isolated memory complaints.

An investigation on chloroprene-compatibilized acrylonitrile butadiene rubber/high density polyethylene blends.

PubMed

Ahmed, Khalil

2015-11-01

Blends of acrylonitrile butadiene rubber/high density polyethylene (NBR/HDPE) compatibilized by Chloroprene rubber (CR) were prepared. A fixed quantity of industrial waste such as marble waste (MW, 40 phr) was also included. The effect of the blend ratio and CR on cure characteristics, mechanical and swelling properties of MW-filled NBR/HDPE blends was investigated. The results showed that the MW-filled NBR/HDPE blends revealed an increase in tensile strength, tear, modulus, hardness and cross-link density for increasing weight ratio of HDPE. The minimum torque (M L) and maximum torque (M H) of blends increased with increasing weight ratio of HDPE while scorch time (ts2) cure time (tc90), compression set and abrasion loss of blends decreased with increasing weight ratio of HDPE. The blends also showed a continuous reduction in elongation at break as well as swelling coefficient with increasing HDPE amount in blends. MW filled blends based on CR provided the most encouraging balance values of overall properties.

An investigation on chloroprene-compatibilized acrylonitrile butadiene rubber/high density polyethylene blends

PubMed Central

Ahmed, Khalil

2014-01-01

Blends of acrylonitrile butadiene rubber/high density polyethylene (NBR/HDPE) compatibilized by Chloroprene rubber (CR) were prepared. A fixed quantity of industrial waste such as marble waste (MW, 40 phr) was also included. The effect of the blend ratio and CR on cure characteristics, mechanical and swelling properties of MW-filled NBR/HDPE blends was investigated. The results showed that the MW-filled NBR/HDPE blends revealed an increase in tensile strength, tear, modulus, hardness and cross-link density for increasing weight ratio of HDPE. The minimum torque (ML) and maximum torque (MH) of blends increased with increasing weight ratio of HDPE while scorch time (ts2) cure time (tc90), compression set and abrasion loss of blends decreased with increasing weight ratio of HDPE. The blends also showed a continuous reduction in elongation at break as well as swelling coefficient with increasing HDPE amount in blends. MW filled blends based on CR provided the most encouraging balance values of overall properties. PMID:26644917

Speciation Methods Used to Assess Potential Health Effects of Toxic Metals in Environmental Materials

USGS Publications Warehouse

Wolf, Ruth E.; Morman, Suzette A.; Plumlee, Geoffrey S.

2008-01-01

Assessing potential exposures to toxic metals or metalloids such as arsenic and chromium in environmental materials is important in protecting public health. The chemical form of an element in, or released from, a material is also important, since some forms, such as Cr(VI), are more toxic than others, for example, Cr(III). We have used a variety of procedures to assess potential exposures to hexavalent chromium in ash and burned soils from October 2007 southern California wildfires. Synthetic lung-fluid and de-ionized water extractions simulate release in the lungs and potential environmental releases due to rainfall. Extracts were analyzed for specific chromium and arsenic species using HPLC-ICP-MS methodology. Results indicate that the highly oxidizing environment in wildfires promotes some chromium conversion to Cr(VI), and that the caustic alkalinity of ash enhances Cr(VI) release and stability in lung fluids and rainfall.

Microstructure and corrosion behaviour in biological environments of the new forged low-Ni Co-Cr-Mo alloys.

PubMed

Hiromoto, Sachiko; Onodera, Emi; Chiba, Akihiko; Asami, Katsuhiko; Hanawa, Takao

2005-08-01

Corrosion behaviour and microstructure of developed low-Ni Co-29Cr-(6, 8)Mo (mass%) alloys and a conventional Co-29Cr-6Mo-1Ni alloy (ASTM F75-92) were investigated in saline solution (saline), Hanks' solution (Hanks), and cell culture medium (E-MEM + FBS). The forging ratios of the Co-29Cr-6Mo alloy were 50% and 88% and that of the Co-29Cr-8Mo alloy was 88%. Ni content in the air-formed surface oxide film of the low-Ni alloys was under the detection limit of XPS. The passive current densities of the low-Ni alloys were of the same order of magnitude as that of the ASTM alloy in all the solutions. The passive current densities of all the alloys did not significantly change with the inorganic ions and the biomolecules. The anodic current densities in the secondary passive region of the low-Ni alloys were lower than that of the ASTM alloy in the E-MEM + FBS. Consequently, the low-Ni alloys are expected to show as high corrosion resistance as the ASTM alloy. On the other hand, the passive current density of the Co-29Cr-6Mo alloy with a forging ratio of 50% was slightly lower than that with a forging ratio of 88% in the saline. The refining of grains by further forging causes the increase in the passive current density of the low-Ni alloy.

Evaluating metabolites in patients with major depressive disorder who received mindfulness-based cognitive therapy and healthy controls using short echo MRSI at 7 Tesla.

PubMed

Li, Yan; Jakary, Angela; Gillung, Erin; Eisendrath, Stuart; Nelson, Sarah J; Mukherjee, Pratik; Luks, Tracy

2016-06-01

Our aim was to evaluate differences in metabolite levels between unmedicated patients with major depressive disorder (MDD) and healthy controls, to assess changes in metabolites in patients after they completed an 8-week course of mindfulness-based cognitive therapy (MBCT), and to exam the correlation between metabolites and depression severity. Sixteen patients with MDD and ten age- and gender-matched healthy controls were studied using 3D short echo-time (20 ms) magnetic resonance spectroscopic imaging (MRSI) at 7 Tesla. Relative metabolite ratios were estimated in five regions of interest corresponding to insula, anterior cingulate cortex (ACC), caudate, putamen, and thalamus. In all cases, MBCT reduced severity of depression. The ratio of total choline-containing compounds/total creatine (tCr) in the right caudate was significantly increased compared to that in healthy controls, while ratios of N-acetyl aspartate (NAA)/tCr in the left ACC, myo-inositol/tCr in the right insula, and glutathione/tCr in the left putamen were significantly decreased. At baseline, the severity of depression was negatively correlated with my-inositol/tCr in the left insula and putamen. The improvement in depression severity was significantly associated with changes in NAA/tCr in the left ACC. This study has successfully evaluated regional differences in metabolites for patients with MDD who received MBCT treatment and in controls using 7 Tesla MRSI.

Evaluation of the normal-to-diseased apparent diffusion coefficient ratio as an indicator of prostate cancer aggressiveness.

PubMed

Lebovici, Andrei; Sfrangeu, Silviu A; Feier, Diana; Caraiani, Cosmin; Lucan, Ciprian; Suciu, Mihai; Elec, Florin; Iacob, Gheorghita; Buruian, Mircea

2014-05-10

We tested the feasibility of a simple method for assessment of prostate cancer (PCa) aggressiveness using diffusion-weighted magnetic resonance imaging (MRI) to calculate apparent diffusion coefficient (ADC) ratios between prostate cancer and healthy prostatic tissue. The requirement for institutional review board approval was waived. A set of 20 standardized core transperineal saturation biopsy specimens served as the reference standard for placement of regions of interest on ADC maps in tumorous and normal prostatic tissue of 22 men with PCa (median Gleason score: 7; range, 6-9). A total of 128 positive sectors were included for evaluation. Two diagnostic ratios were computed between tumor ADCs and normal sector ADCs: the ADC peripheral ratio (the ratio between tumor ADC and normal peripheral zone tissue, ADC-PR), and the ADC central ratio (the ratio between tumor ADC and normal central zone tissue, ADC-CR). The performance of the two ratios in detecting high-risk tumor foci (Gleason 8 and 9) was assessed using the area under the receiver operating characteristic curve (AUC). Both ADC ratios presented significantly lower values in high-risk tumors (0.48 ± 0.13 for ADC-CR and 0.40 ± 0.09 for ADC-PR) compared with low-risk tumors (0.66 ± 0.17 for ADC-CR and 0.54 ± 0.09 for ADC-PR) (p < 0.001) and had better diagnostic performance (ADC-CR AUC = 0.77, sensitivity = 82.2%, specificity = 66.7% and ADC-PR AUC = 0.90, sensitivity = 93.7%, specificity = 80%) than stand-alone tumor ADCs (AUC of 0.75, sensitivity = 72.7%, specificity = 70.6%) for identifying high-risk lesions. The ADC ratio as an intrapatient-normalized diagnostic tool may be better in detecting high-grade lesions compared with analysis based on tumor ADCs alone, and may reduce the rate of biopsies.

Evaluation of the normal-to-diseased apparent diffusion coefficient ratio as an indicator of prostate cancer aggressiveness

PubMed Central

2014-01-01

Background We tested the feasibility of a simple method for assessment of prostate cancer (PCa) aggressiveness using diffusion-weighted magnetic resonance imaging (MRI) to calculate apparent diffusion coefficient (ADC) ratios between prostate cancer and healthy prostatic tissue. Methods The requirement for institutional review board approval was waived. A set of 20 standardized core transperineal saturation biopsy specimens served as the reference standard for placement of regions of interest on ADC maps in tumorous and normal prostatic tissue of 22 men with PCa (median Gleason score: 7; range, 6–9). A total of 128 positive sectors were included for evaluation. Two diagnostic ratios were computed between tumor ADCs and normal sector ADCs: the ADC peripheral ratio (the ratio between tumor ADC and normal peripheral zone tissue, ADC-PR), and the ADC central ratio (the ratio between tumor ADC and normal central zone tissue, ADC-CR). The performance of the two ratios in detecting high-risk tumor foci (Gleason 8 and 9) was assessed using the area under the receiver operating characteristic curve (AUC). Results Both ADC ratios presented significantly lower values in high-risk tumors (0.48 ± 0.13 for ADC-CR and 0.40 ± 0.09 for ADC-PR) compared with low-risk tumors (0.66 ± 0.17 for ADC-CR and 0.54 ± 0.09 for ADC-PR) (p < 0.001) and had better diagnostic performance (ADC-CR AUC = 0.77, sensitivity = 82.2%, specificity = 66.7% and ADC-PR AUC = 0.90, sensitivity = 93.7%, specificity = 80%) than stand-alone tumor ADCs (AUC of 0.75, sensitivity = 72.7%, specificity = 70.6%) for identifying high-risk lesions. Conclusions The ADC ratio as an intrapatient-normalized diagnostic tool may be better in detecting high-grade lesions compared with analysis based on tumor ADCs alone, and may reduce the rate of biopsies. PMID:24885552

[1-13C]Glucose entry in neuronal and astrocytic intermediary metabolism of aged rats. A study of the effects of nicergoline treatment by 13C NMR spectroscopy.

PubMed

Miccheli, Alfredo; Puccetti, Caterina; Capuani, Giorgio; Di Cocco, Maria Enrica; Giardino, Luciana; Calzà, Laura; Battaglia, Angelo; Battistin, Leontino; Conti, Filippo

2003-03-14

Age-related changes in glucose utilization through the TCA cycle were studied using [1-13C]glucose and 13C, 1H NMR spectroscopy on rat brain extracts. Significant increases in lactate levels, as well as in creatine/phosphocreatine ratios (Cr/PCr), and a decrease in N-acetyl-aspartate (NAA) and aspartate levels were observed in aged rat brains as compared to adult animals following glucose administration. The total amount of 13C from [1-13C]glucose incorporated in glutamate, glutamine, aspartate and GABA was significantly decreased in control aged rat brains as compared to adult brains. The results showed a decrease in oxidative glucose utilization of control aged rat brains. The long-term nicergoline treatment increased NAA and glutamate levels, and decreased the lactate levels as well as the Cr/PCr ratios in aged rat brains as compared to adult rats. The total amount of 13C incorporated in glutamate, glutamine, aspartate, NAA and GABA was increased by nicergoline treatment, showing an improvement in oxidative glucose metabolism in aged brains. A significant increase in pyruvate carboxylase/pyruvate dehydrogenase activity (PC/PDH) in the synthesis of glutamate in nicergoline-treated aged rats is consistent with an increase in the transport of glutamine from glia to neurons for conversion into glutamate. In adult rat brains, no effect of nicergoline on glutamate PC/PDH activity was observed, although an increase in PC/PDH activity in glutamine was, suggesting that nicergoline affects the glutamate/glutamine cycle between neurons and glia in different ways depending on the age of animals. These results provide new insights into the effects of nicergoline on the CNS.

Effects of hyperglycemia and effects of ketosis on cerebral perfusion, cerebral water distribution, and cerebral metabolism.

PubMed

Glaser, Nicole; Ngo, Catherine; Anderson, Steven; Yuen, Natalie; Trifu, Alexandra; O'Donnell, Martha

2012-07-01

Diabetic ketoacidosis (DKA) may cause brain injuries in children. The mechanisms responsible are difficult to elucidate because DKA involves multiple metabolic derangements. We aimed to determine the independent effects of hyperglycemia and ketosis on cerebral metabolism, blood flow, and water distribution. We used magnetic resonance spectroscopy to measure ratios of cerebral metabolites (ATP to inorganic phosphate [Pi], phosphocreatine [PCr] to Pi, N-acetyl aspartate [NAA] to creatine [Cr], and lactate to Cr) and diffusion-weighted imaging and perfusion-weighted imaging to assess cerebral water distribution (apparent diffusion coefficient [ADC] values) and cerebral blood flow (CBF) in three groups of juvenile rats (hyperglycemic, ketotic, and normal control). ATP-to-Pi ratio was reduced in both hyperglycemic and ketotic rats in comparison with controls. PCr-to-Pi ratio was reduced in the ketotic group, and there was a trend toward reduction in the hyperglycemic group. No significant differences were observed in NAA-to-Cr or lactate-to-Cr ratio. Cortical ADC was reduced in both groups (indicating brain cell swelling). Cortical CBF was also reduced in both groups. We conclude that both hyperglycemia and ketosis independently cause reductions in cerebral high-energy phosphates, CBF, and cortical ADC values. These effects may play a role in the pathophysiology of DKA-related brain injury.

Synthesis and Characterization of Allophane-Like as Chromium (Cr) Ion Adsorbent

NASA Astrophysics Data System (ADS)

Pranoto; Purnawan, C.; Husnina, A. N.

2018-03-01

The synthesis and characterization of allophane-like as chrom (Cr) ion adsorbent has been studied. The objectives of this study is to determine the characteristics of allophane-like and determine ratio of Al/Si, chromium solution pH, and contact time to get the best decreasing metal ion chrom (Cr) adsorption condition. The study was conducted with the ratio of Al/Si ratios 0.5; 0.75; 1.0; 1.25 and 1.5 from Tetraetyl Orthosilicate (TEOS) solution and Aluminium Nitrate Nonahydrate [Al(NO3)3.9H2O] in pH 3-4. The result of synthetic was characterized on functional groups and cristallinity. Experiment of adsorption ability using variation of Cr solution pH 3-7, contact time 30, 60, 90 and 120 minutes with batch method. The results by FTIR shows that functional groups-OH, the asymmetry groups O-Si-O or O-Al-O, relatively weak absorption which stronger then the presence of OH and bending vibration Si-O or Al-O on allophane-like. The best conditions of chromium metal adsorption with adsorbent allophane-like was obtained at pH 5, contact time 90 minutes, and the ratio Al/Si 1.5. Types of adsorption in this study follows Freundlich and Langmuir isotherm.

Effect of citric acid on material properties of ZnGa2O4:Cr3+ nanopowder prepared by sol-gel method

NASA Astrophysics Data System (ADS)

Hussen, Megersa K.; Dejene, Francis B.; Gonfa, Girma G.

2018-05-01

This paper reports the material properties of Cr3+ (1.0 mol%)-doped ZnGa2O4 nanopowders prepared by citric acid-assisted sol-gel method with metal cations (Zn + Ga) to citric (M:CA) molar ratios of (1:0.5, 1:1, 1:3 and 1:4). The X-ray diffraction (XRD) results show that the synthesized nanoparticles are cubic structured and concentration of citric acid did not affect the structure. The scanning electron microscope (SEM) shows that the increase of the M:CA molar ratio favors the formation of smaller nano particle of ZnGa2O4:Cr3+. The photoluminescence (PL) is found to be maximum for sample with M:CA ratio of 1:1. Further increase in citric acid leads to significant decrease in the PL intensity. Energy-dispersive X-ray spectroscopy (EDS) measurement confirms the presence of the Zn, Ga, O and Cr ions. Ultraviolet-visible (UV-Vis) spectrophotometer measurement shows an increase in reflectance in visible region and the energy band gap was found to decrease with an increase in citric acid molar ratio. The emission spectra, particle size and photoluminescence lifetimes are comparable with reports on bioimaging applications.

The Curious Case of High-energy Deuterons in Galactic Cosmic Rays

NASA Astrophysics Data System (ADS)

Tomassetti, Nicola; Feng, Jie

2017-02-01

A new analysis of cosmic ray (CR) data collected by the SOKOL experiment in space found that the deuteron-to-helium ratio at energies between 500 and 2000 GeV/nucleon takes the value d/He ˜ 1.5. As we will show, this result cannot be explained by standard models of secondary CR production in the interstellar medium and points to the existence of a high-energy source of CR deuterons. To account for the deuteron excess in CRs, we argue that the only viable solution is hadronic interaction processes of accelerated particles inside old supernova remnants (SNRs). From this mechanism, however, the B/C ratio is also expected to increase at energies above ˜50 of GeV/nucleon, in conflict with new precision data just released by the AMS-02 experiment. Hence, if this phenomenon is a real physical effect, hadronic production of CR deuterons must occur in SNRs characterized by low metal abundance. In such a scenario, the sources accelerating C-{N}-O nuclei are not the same as those accelerating helium or protons, so that the connection between d/He ratio and B/C ratio is broken, and the latter cannot be used to place constraints on the production of light isotopes or antiparticles.

The Characteristics and Generating Mechanism of Large Precipitates in Ti-Containing H13 Tool Steel

NASA Astrophysics Data System (ADS)

Xie, You; Cheng, Guoguang; Chen, Lie; Zhang, Yandong; Yan, Qingzhong

2017-02-01

The characteristics of large precipitates in H13 tool steel with 0.015wt% Ti were studied. The result shows that three types of phases larger than 1 μm exist in the as-cast ingot, that is, (Ti, V) (C, N) type phase, (V, Mo, Cr)C type phase and sulfide. (Ti, V) (C, N) type phase could be further classified as the homogeneous Ti-rich one and the Ti-V-rich one in which Ti/V ratio gradually changes. (V, Mo, Cr)C type phase contains the V-rich one and the Mo-Cr-rich one. The compositional characteristics in all of them have little relation with the cutting position or cooling rate. The precipitating process could be well described through calculation by Thermo-Calc software. During solidification, the primary phase (Ti, V)(C, N) first starts to precipitate in the form of Ti-rich carbonitride. With the development of solidification, the ratio of Ti decreases and that of V increases. Then the primary phase Ti-V-rich (Ti, V)(C, N) and V-rich (V, Mo, Cr)C appears successively. Mo-Cr-rich (V, Mo, Cr)C phase does not precipitate until the solidification process reaches to the end. Sulfide precipitates before (V, Mo, Cr)C type phase and it could act as the nucleus of (V, Mo, Cr)C.

Measuring the lactate-to-creatine ratio via 1H NMR spectroscopy can be used to noninvasively evaluate apoptosis in glioma cells after X-ray irradiation.

PubMed

Li, Hongxia; Cui, Yi; Li, Fuyan; Shi, Wenqi; Gao, Wenjing; Wang, Xiao; Zeng, Qingshi

2018-01-01

Radiotherapy is among the commonly applied treatment options for glioma, which is one of the most common types of primary brain tumor. To evaluate the effect of radiotherapy noninvasively, it is vital for oncologists to monitor the effects of X-ray irradiation on glioma cells. Preliminary research had showed that PKC-ι expression correlates with tumor cell apoptosis induced by X-ray irradiation. It is also believed that the lactate-to-creatine (Lac/Cr) ratio can be used as a biomarker to evaluate apoptosis in glioma cells after X-ray irradiation. In this study, we evaluated the relationships between the Lac/Cr ratio, apoptotic rate, and protein kinase C iota (PKC-ι) expression in glioma cells. Cells of the glioma cell lines C6 and U251 were randomly divided into 4 groups, with every group exposed to X-ray irradiation at 0, 1, 5, 10 and 15 Gy. Single cell gel electrophoresis (SCGE) was conducted to evaluate the DNA damage. Flow cytometry was performed to measure the cell cycle blockage and apoptotic rates. Western blot analysis was used to detect the phosphorylated PKC-ι (p-PKC-ι) level. 1 H NMR spectroscopy was employed to determine the Lac/Cr ratio. The DNA damage increased in a radiation dose-dependent manner ( p  < 0.05). With the increase in X-ray irradiation, the apoptotic rate also increased (C6, p  < 0.01; U251, p  < 0.05), and the p-PKC-ι level decreased (C6, p  < 0.01; U251, p  < 0.05). The p-PKC-ι level negatively correlated with apoptosis, whereas the Lac/Cr ratio positively correlated with the p-PKC-ι level. The Lac/Cr ratio decreases with an increase in X-ray irradiation and thus can be used as a biomarker to reflect the effects of X-ray irradiation in glioma cells.

Hypothalamic damage in multiple sclerosis correlates with disease activity, disability, depression, and fatigue.

PubMed

Kantorová, E; Poláček, H; Bittšanský, M; Baranovičová, E; Hnilicová, P; Čierny, D; Sivák, Š; Nosáľ, V; Zeleňák, K; Kurča, E

2017-04-01

Disturbances in the hypothalamo-pituitary axis are supposed to modulate activity of multiple sclerosis (MS). We hypothesised that the extent of HYP damage may determine severity of MS and may be associated with the disease evolution. We suggested fatigue and depression may depend on the degree of damage of the area. 33 MS patients with relapsing-remitting and secondary progressive disease, and 24 age and sex-related healthy individuals (CON) underwent 1H-MR spectroscopy (1H-MRS) of the hypothalamus. Concentrations of glutamate + glutamin (Glx), cholin (Cho), myoinositol (mIns), N-acetyl aspartate (NAA) expressed as ratio with creatine (Cr) and NAA were correlated with markers of disease activity (RIO score), Multiple Sclerosis Severity Scale (MSSS), Depressive-Severity Status Scale and Simple Numerical Fatigue Scale. Cho/Cr and NAA/Cr ratios were decreased and Glx/NAA ratio increased in MS patients vs CON. Glx/NAA, Glx/Cr, and mIns/NAA were significantly higher in active (RIO 1-2) vs non-active MS patients (RIO 0). Glx/NAA and Glx/Cr correlated with MSSS and fatigue score, and Glx/Cr with depressive score of MS patients. In CON, relationships between Glx/Cr and age, and Glx/NAA and fatigue score were inverse. Our study provides the first evidence about significant hypothalamic alterations correlating with clinical outcomes of MS, using 1H-MRS. The combination of increased Glu or mIns with reduced NAA in HYP reflects whole-brain activity of MS. In addition, excess of Glu is linked to severe disease course, depressive mood and fatigue in MS patients, suggesting superiority of Glu over other metabolites in determining MS burden.

Antidepressant effect detected on proton magnetic resonance spectroscopy in drug-naïve female patients with first-episode major depression.

PubMed

Kaymak, Semra Ulusoy; Demir, Başaran; Oğuz, Kader Karli; Sentürk, Senem; Uluğ, Berna

2009-06-01

Recent neuroimaging studies support functional and structural alterations in the dorsolateral prefrontal cortex (DLPFC), particularly on the left side in patients with major depressive disorders (MDD). The aim of the present study was to examine the biochemical characteristics of left DLPFC as measured on proton ((1)H) magnetic resonance spectroscopy (MRS) in patients with drug-naïve first-episode MDD and a healthy control group. A second aim was to assess the effect of antidepressant treatment on the metabolites of DLPFC. Short-echo single-voxel (1)H-MRS was done for the left DLPFC in 17 female drug-free MDD patients (mean age +/- SD, 30.9 +/- 6.9 years) and 13 matched control subjects (mean age +/- SD, 29.1 +/- 6.2 years) and was repeated at 8 weeks following antidepressant treatment. Comparison of baseline values indicated that there were no significant differences in any of the metabolite ratios (N-acetyl aspartate/creatine [NAA/Cr], myoinositol [Ino]/Cr, and choline [Cho]/Cr) between patients and controls. Significant differences were detected between pre- and post-treatment Ino/Cr ratios (0.67 +/- 0.13, 0.58 +/- 0.22, P = 0.032, respectively), although there was no difference in NAA/Cr and Cho/Cr ratios. Although no significant metabolic alterations exist in female patients with drug-naïve first-episode MDD as evaluated on (1)H-MRS, an increase in Ino/Cr was observed following 8-week antidepressant treatment. These findings give rise to the possibility that non-neuronal cells, particularly glial cells that are probably damaged, play a role in the action of antidepressant treatment.

Effects of chromium and chromium + vitamin C combination on metabolic, oxidative, and fear responses of broilers transported under summer conditions

NASA Astrophysics Data System (ADS)

Perai, A. H.; Kermanshahi, H.; Moghaddam, H. Nassiri; Zarban, A.

2015-04-01

A total of 240 female broilers (42 days old) were randomly assigned to four groups with six replicates and fed either a basal diet (two control groups) or a basal diet supplemented with either 1,200 μg Cr+3 from chromium (Cr) methionine/kg (Cr group) or 1,200 μg Cr+3 from Cr methionine plus 800 mg vitamin C (Vit C)/kg of diet (Cr + Vit C group). After 7 days on the dietary treatment, all groups except one of the controls were transported for 3 h under the summer conditions. Performance parameters were not influenced by dietary treatments. The plasma concentrations of insulin, triiodothyronine, triglyceride, and the ratio of triiodothyronine/thyroxin were decreased and the ratio of glucose/insulin was increased due to transport process. Road transportation also increased the plasma concentrations of protein, cholesterol, aspartate aminotransferase, and creatine kinase and decreased the concentration of low-density lipoprotein cholesterol in the Cr + Vit C group. The pretransport concentrations of insulin and triiodothyronine were highest in the Cr + Vit C group. The concentration of phosphorous was lower in the Cr group than that in the other groups after transport. No significant effects of dietary treatments were observed on the other biochemical parameters. Transport increased malondialdehyde concentration in the control group and did not change plasma total antioxidant capacity and erythrocyte glutathione peroxidase activity. Either in combination or alone, Cr increased plasma total antioxidant capacity (before transport P ≤ 0.05, after transport P = 0.07) but did not affect the concentration of malondialdehyde and activity of glutathione peroxidase. The duration of tonic immobility (TI) was similar between nontransported control chicks and transported chicks without any supplements. Pretreatment with Cr + Vit C significantly reduced the duration of TI.

Extremely 54Cr- and 50Ti-rich Presolar Oxide Grains in a Primitive Meteorite: Formation in Rare Types of Supernovae and Implications for the Astrophysical Context of Solar System Birth

NASA Astrophysics Data System (ADS)

Nittler, Larry R.; O’D. Alexander, Conel M.; Liu, Nan; Wang, Jianhua

2018-04-01

We report the identification of 19 presolar oxide grains from the Orgueil CI meteorite with substantial enrichments in 54Cr, with 54Cr/52Cr ratios ranging from 1.2 to 56 times the solar value. The most enriched grains also exhibit enrichments at mass-50, most likely due in part to 50Ti, but close-to-normal or depleted 53Cr/52Cr ratios. There is a strong inverse relationship between 54Cr enrichment and grain size; the most extreme grains are all <80 nm in diameter. Comparison of the isotopic data with predictions of nucleosynthesis calculations indicate that these grains most likely originated in either rare, high-density Type Ia supernovae (SN Ia), or in electron-capture supernovae (ECSN), which may occur as the end stage of evolution for stars of mass 8–10 M ⊙. This is the first evidence for preserved presolar grains from either type of supernova. An ECSN origin is attractive, as these likely occur much more frequently than high-density SN Ia, and their evolutionary timescales (∼20 Myr) are comparable to those of molecular clouds. Self-pollution of the Sun’s parent cloud from an ECSN may explain the heterogeneous distribution of n-rich isotopic anomalies in planetary materials, including a recently reported dichotomy in Mo isotopes in the solar system. The stellar origins of three grains with solar 54Cr/52Cr, but anomalies in 50Cr or 53Cr, as well as of a grain enriched in 57Fe, are unclear.

The Urinary Uric Acid/Creatinine Ratio is An Adjuvant Marker for Perinatal Asphyxia.

PubMed

Bhongir, Aparna Varma; Yakama, Akhil Varma Venkata; Saha, Subhajit; Radia, Sejal B; Pabbati, Jayalakshmi

2015-09-01

To assess the urinary uric acid/creatinine ratio (UA/Cr) in relation to Apgar score and cord blood gas analysis in identification of perinatal asphyxia and to define the cutoff values. case control study. The newborns admitted in the department of pediatrics and NICU of Mediciti Institute of Medical Science, Ghanpur, Medchal mandal, Telangana from May-July 2011 were enrolled. The study was conducted on 31 (18 males, 13 females) controls and 18 (12males, 6 females) asphyxiated neonates. 5ml of arterial cord blood of newborn collected at the time of birth and spot urine samples were collected within 24-72 hours of life. Cord blood gas analysis were done immediately and Urinary uric acid was measured by modified Uricase method, urinary creatinine by modified kinetic Jaffe's reaction. The mean urinary uric acid and creatinine ratio (2.58± 0.48 vs 1.89 ± 0.59) is significantly higher in Asphyxiated group than in the control group. The umbilical cord blood pH had significant positive correlation with 1 st minute Apgar score (r= 0.41, p=0.003), 5 th minute Apgar (r= 0.44, p=0.002), while urinary UA/Cr ratio had significant negative correlation with cord blood pH (r= -0.63, p=0.002). Urinary UA/Cr ratio with criterion of >2.43 had 80% sensitivity, 87.5% specificity with AUC of 0.84 (p=0.003) had a better predictive value. Urinary UA/Cr ratio is easy, non-invasive, painless and economical adjuvant parameter with better predictive value for diagnosing perinatal asphyxia with simple diagnostic equipment.

A double-blind, randomized comparative study to investigate the morphine to hydromorphone conversion ratio in Japanese cancer patients

PubMed Central

Inoue, Satoshi; Saito, Yoji; Tsuneto, Satoru; Aruga, Etsuko; Ogata, Takeshi; Uemori, Mitsutoshi

2018-01-01

Abstract Objective To confirm the morphine to hydromorphone conversion ratio for hydromorphone (DS-7113b) immediate-release tablets in cancer patients who achieved pain control with oral morphine. Methods This was a multicenter, active-controlled, randomized, double-blind, parallel-group, comparative study (July 2013 to December 2014) at 39 Japanese sites. Seventy-one patients (aged >20 years) who had achieved pain control with morphine 60 mg/day and 90 mg/day were randomly allocated 1:1 to hydromorphone immediate-release tablets at a dose converted at a hydromorphone:morphine ratio of 1:5 or 1:8, respectively, and treated for up to 5 days. The efficacy was evaluated as the pain control ratio. Results The pain control ratio in the full analysis set was 83.3% (25/30) in the conversion ratio 1:5 group and 95.0% (38/40) in the conversion ratio 1:8 group, and both groups demonstrated highly successful pain control. The incidence of adverse events was 46.7% (14/30) in the conversion ratio 1:5 group and 58.5% (24/41) in the 1:8 group; the difference was not clinically relevant. Frequently observed adverse events (incidence ≥5%) were nausea, vomiting, diarrhea, somnolence and dyspnea. Conclusions A high pain control ratio was maintained by a switch at either conversion ratio, and no notable difference was observed in the incidence of adverse events. A switch from morphine to hydromorphone is effective at a dose converted at ratios of 1:5 and 1:8. PMID:29635632

Analysis of the rationale for, and consequences of, nonprofit and for-profit ownership conversions.

PubMed Central

Mark, T L

1999-01-01

OBJECTIVES: To examine percursors to private hospitals conversion, both from nonprofit status to for-profit status and from for-profit to nonprofit status, as well as the effect of hospital conversions on hospital profitability, efficiency, staffing, and the probability of closure. DATA SOURCES: The Health Care Financing Administration's Medicare Cost Reports and the American Hospital Association's Annual Survey of Hospitals. STUDY DESIGN: Bivariate and multivariate analyses comparing conversion hospitals to nonconversion hospitals over time were conducted. DATA EXTRACTION METHODS: The study sample consisted of all private acute care hospital conversions that occurred from 1989 through 1992. PRINCIPAL FINDINGS: Hospitals that converted had significantly lower profit margins prior to converting than did nonconversion hospitals. This was particularly true for nonprofit to for-profit conversions. After converting, both nonprofit and for-profit hospitals significantly improved their profitability. Nonprofit to for-profit hospital conversions were associated with a decrease in the ratio of staff to patients. No association was found between for-profit to nonprofit conversion and staff-to-patient ratios. The difference seems partially attributed to the fact that nonprofit hospitals that converted had higher staff ratios than the industry average. For-profit to nonprofit hospital conversions were associated with an increase in the ratio of registered nurses to patients and administrators to patients, despite the fact that nonprofit and for-profit hospitals did not differ in these ratios. CONCLUSIONS: The improvement in financial performance following hospital conversions may be a benefit to the community that policymakers want to consider when regulating hospital conversions. PMID:10201853

Altered chemical metabolites in the amygdala-hippocampus region contribute to autistic symptoms of autism spectrum disorders.

PubMed

Endo, Taro; Shioiri, Toshiki; Kitamura, Hideaki; Kimura, Teruo; Endo, Sumio; Masuzawa, Naio; Someya, Toshiyuki

2007-11-01

Although several previous studies have been conducted, the neural basis of autism spectrum disorder (ASD) is poorly understood. The objective of the present study was to determine whether individuals with ASD have altered brain chemical metabolites and whether such alterations are related to their autistic symptoms. N-acetylaspartate (NAA)/creatine (Cr) and choline/Cr ratios in the right medial temporal lobe (MTL), medial prefrontal cortex, and cerebellar vermis were measured in 38 individuals with ASD (mean age = 12.9 years), including 12 with autism, 15 with Asperger's Disorder, and 11 with pervasive developmental disorder not otherwise specified (PDD-NOS), and 16 matched healthy control subjects (mean age = 11.5 years) with proton magnetic resonance spectroscopy. Autistic symptoms were assessed by the Childhood Autistic Rating Scale-Tokyo Version. There was a significant group difference for NAA/Cr ratio in the right MTL between the autism, Asperger's Disorder, PDD-NOS, and control groups (p < .001), and the autism group had a significantly lower NAA/Cr ratio compared with the PDD-NOS (p < .001) and control (p < .001) groups. In the ASD group, there was a significant negative correlation between NAA/Cr ratio in the right MTL and their Childhood Autistic Rating Scale-Tokyo Version total scores (r = -.44, p = .01) and subscales of emotional response (r = -.38, p = .02) and listening response (r = -.54, p = .001). The results of the present study suggest that subjects with ASD have abnormalities of neural integrity in the amygdala-hippocampus region that are related to their severity and social impairments.

GABA Levels Are Decreased After Stroke and GABA Changes During Rehabilitation Correlate With Motor Improvement

PubMed Central

Blicher, Jakob Udby; Near, Jamie; Næss-Schmidt, Erhard; Stagg, Charlotte J.; Johansen-Berg, Heidi; Nielsen, Jørgen Feldbæk; Østergaard, Leif; Ho, Yi-Ching Lynn

2017-01-01

Background and Objective γ-Aminobutyric acid (GABA) is the dominant inhibitory neurotransmitter in the brain and is important in motor learning. We aimed to measure GABA content in primary motor cortex poststroke (using GABA-edited magnetic resonance spectroscopy [MRS]) and in relation to motor recovery during 2 weeks of constraint-induced movement therapy (CIMT). Methods Twenty-one patients (3-12 months poststroke) and 20 healthy subjects were recruited. Magnetic resonance imaging structural T1 and GABA-edited MRS were performed at baseline and after CIMT, and once in healthy subjects. GABA:creatine (GABA:Cr) ratio was measured by GABA-edited MRS. Motor function was measured using Wolf Motor Function Test (WMFT). Results Baseline comparison between stroke patients (n = 19) and healthy subjects showed a significantly lower GABA:Cr ratio in stroke patients (P < .001) even after correcting for gray matter content in the voxel (P < .01) and when expressing GABA relative to N-acetylaspartic acid (NAA; P = .03). After 2 weeks of CIMT patients improved significantly on WMFT, but no consistent change across the group was observed for the GABA:Cr ratio (n = 17). However, the extent of improvement on WMFT correlated significantly with the magnitude of GABA:Cr changes (P < .01), with decreases in GABA:Cr ratio being associated with better improvements in motor function. Conclusions In patients 3 to 12 months poststroke, GABA levels are lower in the primary motor cortex than in healthy subjects. The observed association between GABA and recovery warrants further studies on the potential use of GABA MRS as a biomarker in poststroke recovery. PMID:25055837

Mn-Cr isotopic systematics of Chainpur chondrules and bulk ordinary chondrites

NASA Technical Reports Server (NTRS)

Nyquist, L.; Lindstrom, D.; Wiesmann, H.; Bansal, B.; Shih, C.-Y.; Mittlefehldt, D.; Martinez, R.; Wentworth, S.

1994-01-01

We report on ongoing study of the Mn-Cr systematics of individual Chainpur (LL3.4) chondrules and compare the results to those for bulk ordinary chondrites. Twenty-eight chondrules were surveyed for abundances of Mn, Cr, Na, Fe, Sc, Hf, Ir, and Zn by INAA. Twelve were chosen for SEM/EDX and high-precision Cr-isotopic studies on the basis of LL-chondrite-normalized Mn(LL), Sc(LL), (Mn/Fe)(LL), and (Sc/Fe)(LL) as well as their Mn/Cr ratios. Classification into textural types follows from SEM/EDX examination of interior surfaces.

Anillin acts as a bifunctional linker coordinating midbody ring biogenesis during cytokinesis

PubMed Central

Kechad, Amel; Jananji, Silvana; Ruella, Yvonne; Hickson, Gilles R. X.

2013-01-01

Summary Animal cell cytokinesis proceeds via constriction of an actomyosin-based contractile ring (CR) [1, 2]. Upon reaching a diameter of ~1 μm [3], a midbody ring (MR) forms to stabilize the intercellular bridge until abscission [4-6]. How MR formation is coupled to CR closure and how plasma membrane anchoring is maintained at this key transition is unknown. Time-lapse microscopy of Drosophila S2 cells depleted of the scaffold protein, Anillin [7-9], revealed that Anillin is required for complete closure of the CR and formation of the MR. Truncation analysis revealed that Anillin N-termini connected with the actomyosin CR and supported formation of stable MR-like structures, but these could not maintain anchoring of the plasma membrane. Conversely, Anillin C-termini failed to connect with the CR or MR but recruited the septin, Peanut, to ectopic structures at the equatorial cortex. Peanut depletion mimicked truncation of the Anillin C-terminus, resulting in MR-like structures that failed to anchor the membrane. These data demonstrate that Anillin coordinates the transition from CR to MR, and that it does so by linking two distinct cortical cytoskeletal elements. One apparently acts as the core structural template for MR assembly, while the other ensures stable anchoring of the plasma membrane beyond the CR stage. PMID:22226749

Effect of first-line endocrine therapy in patients with hormone-sensitive advanced breast cancer: a network meta-analysis.

PubMed

Zhang, Tingting; Feng, Fubin; Zhao, Wenge; Tian, Jinhui; Yao, Yan; Zhou, Chao; Dong, Shengjie; Wang, Congcong; Zang, Chuanxin; Lv, Qingliang; Sun, Changgang

2018-01-01

Endocrine therapy is the cornerstone treatment for patients with hormone receptor-positive advanced breast cancer. We aimed to assess the effectiveness of various first-line endocrine monotherapies or combinations to determine the optimal sequence in a network meta-analysis. We searched PubMed, EMBASE, and the Cochrane Library for randomized controlled trials (RCTs) from inception up to November 21, 2017. We included only RCTs that assessed the effectiveness of the following treatments as a monotherapy or in combination as the first-line treatment: tamoxifen, anastrozole, letrozole, exemestane, fulvestrant, palbociclib, and ribociclib. The results were presented with pooled odds ratio or hazard ratio (HR), and 95% credible interval (CrI). The primary outcomes were objective response rate (ORR) and progression-free survival/time to progression. A total of 16 eligible articles (14 RCTs) involving 6,602 patients treated with 10 different first-line endocrine therapies were assessed in our network meta-analysis. Palbociclib plus letrozole was superior to anastrozole, letrozole, exemestane, fulvestrant 500 mg, and anastrozole plus fulvestrant (loading dose) (HR=0.44, 95% CrI: 0.33-0.58; HR=0.56, 95% CrI: 0.45-0.68; HR=0.45, 95% CrI: 0.32-0.61; HR=0.58, 95% CrI: 0.42-0.81; HR=0.50, 95% CrI: 0.37-0.68; respectively). However, there is no significant advantage compared with ribociclib plus letrozole (HR=1.00, 95% CrI: 0.72-1.39). In terms of ORR, ribociclib plus letrozole is more effective than palbociclib plus letrozole (odds ratio=1.30, 95% CrI: 0.83-2.02). Palbociclib plus letrozole and ribociclib plus letrozole might be the optimal first-line endocrine therapeutic choices for hormone receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer due to a longer progression-free survival/time to progression and a more efficacious ORR.

Screening for X-linked creatine transporter (SLC6A8) deficiency via simultaneous determination of urinary creatine to creatinine ratio by tandem mass-spectrometry.

PubMed

Mercimek-Mahmutoglu, Saadet; Muehl, Adolf; Salomons, Gajja S; Neophytou, Birgit; Moeslinger, Dorothea; Struys, Eduard; Bodamer, Olaf A; Jakobs, Cornelis; Stockler-Ipsiroglu, Sylvia

2009-04-01

High urinary creatine to creatinine ratio (U-CrCrtR) is a potential diagnostic marker of X-linked creatine transporter (SLC6A8) deficiency. We developed a tandem mass-spectrometry method to simultaneously determine urinary creatine and creatinine in 975 individuals (0-18 years). U-CrCrtR increased up to 8 years and decreased thereafter. U-CrCrtR was 2.29 and 2.12 (99th percentile: 1.87) in two males with subsequently confirmed SLC6A8 mutations. The frequency of SLC6A8 deficiency was 2.3% in 157 males at risk.

Lack of effect of oral choline supplement on the concentrations of choline metabolites in human brain.

PubMed

Tan, J; Bluml, S; Hoang, T; Dubowitz, D; Mevenkamp, G; Ross, B

1998-06-01

Recent reports suggest that oral choline supplement may alter the cerebral choline/creatine (Cho/Cr) ratio and might be used to treat neurodegenerative disorders of cholinergic transmission. Using both 1H and 31P MRS, we reexamined the Cho/Cr ratio and quantified cerebral choline and its major constituents: phosphoethanolamine (PE), phosphorylcholine (PC), glycerophosphorylethanolamine (GPE), and glycerophosphorylcholine (GPC). In the four brain locations examined, no significant increases in Cho/Cr, [Cho], or in its major constituents were found in response to an oral challenge of 50 mg/kg of choline bitartrate. Oral choline did not significantly affect human cerebral metabolism in the short term.

Easy Fabrication of Highly Thermal-Stable Cellulose Nanocrystals Using Cr(NO3)3 Catalytic Hydrolysis System: A Feasibility Study from Macro- to Nano-Dimensions

PubMed Central

Chen, You Wei; Tan, Thean Heng; Lee, Hwei Voon; Abd Hamid, Sharifah Bee

2017-01-01

This study reported on the feasibility and practicability of Cr(NO3)3 hydrolysis to isolate cellulose nanocrystals (CNCCr(NO3)3) from native cellulosic feedstock. The physicochemical properties of CNCCr(NO3)3 were compared with nanocellulose isolated using sulfuric acid hydrolysis (CNCH2SO4). In optimum hydrolysis conditions, 80 °C, 1.5 h, 0.8 M Cr(NO3)3 metal salt and solid–liquid ratio of 1:30, the CNCCr(NO3)3 exhibited a network-like long fibrous structure with the aspect ratio of 15.7, while the CNCH2SO4 showed rice-shape structure with an aspect ratio of 3.5. Additionally, Cr(NO3)3-treated CNC rendered a higher crystallinity (86.5% ± 0.3%) with high yield (83.6% ± 0.6%) as compared to the H2SO4-treated CNC (81.4% ± 0.1% and 54.7% ± 0.3%, respectively). Furthermore, better thermal stability of CNCCr(NO3)3 (344 °C) compared to CNCH2SO4 (273 °C) rendered a high potential for nanocomposite application. This comparable effectiveness of Cr(NO3)3 metal salt provides milder hydrolysis conditions for highly selective depolymerization of cellulosic fiber into value-added cellulose nanomaterial, or useful chemicals and fuels in the future. PMID:28772403

Magnetic resonance spectroscopy findings in photosensitive idiopathic generalized epilepsy.

PubMed

Aydin-Ozemir, Zeynep; Terzibasioglu, Ege; Altindag, Ebru; Sencer, Serra; Baykan, Betul

2010-01-01

Studies investigating the pathophysiology of epileptic photosensitivity indicate variable involvement of particular brain regions. Our aim was to identify metabolic differences between photosensitive idiopathic generalized epilepsy (IGE) patients and nonphotosensitive IGE patients and normal healthy subjects by using Magnetic Resonance Spectroscopy (MRS). Fourteen patients diagnosed with photosensitive IGE were investigated. The control groups consisted of 14 age- and sex-matched healthy volunteers and 14 IGE patients without photosensitivity. MRS measurements of N-acetylaspartate (NAA), choline-containing compounds (Cho), creatine (Cr) were performed in the frontal and occipital cortex and the thalamus bilaterally using a stimulated echo acquisition mode (STEAM) technique with a voxel size of 20 x 20 x 20 mm. The values of the patients with IGE were compared with those of the normal controls and within subgroups according to the clinical variables by appropriate statistical tests. Photosensitive IGE patients showed significantly decreased concentrations of NAA in the right frontal lobe and left thalamus, decreased NAA/Cr ratio in left thalamus and significantly increased concentrations of Cho/Cr ratio in the right frontal lobe and NAA/Cr in the left occipital lobe when compared to normal controls. Furthermore, left occipital NAA concentration increased and left thalamus NAA/Cr ratios were decreased from the IGE patients without photosensitivity but without reaching statistical significance. Our results support previous MR studies suggesting an asymmetrical neuronal dysfunction in favor of the dominant occipital cortex and thalamus in photosensitive IGE patients.

Distribution of 26Al in the CR chondrite chondrule-forming region of the protoplanetary disk

NASA Astrophysics Data System (ADS)

Schrader, Devin L.; Nagashima, Kazuhide; Krot, Alexander N.; Ogliore, Ryan C.; Yin, Qing-Zhu; Amelin, Yuri; Stirling, Claudine H.; Kaltenbach, Angela

2017-03-01

We report on the mineralogy, petrography, and in situ measured oxygen- and magnesium-isotope compositions of eight porphyritic chondrules (seven FeO-poor and one FeO-rich) from the Renazzo-like carbonaceous (CR) chondrites Graves Nunataks 95229, Grosvenor Mountains 03116, Pecora Escarpment 91082, and Queen Alexandra Range 99177, which experienced minor aqueous alteration and very mild thermal metamorphism. We find no evidence that these processes modified the oxygen- or Al-Mg isotope systematics of chondrules in these meteorites. Olivine, low-Ca pyroxene, and plagioclase within an individual chondrule have similar O-isotope compositions, suggesting crystallization from isotopically uniform melts. The only exceptions are relict grains in two of the chondrules; these grains are 16O-enriched relative to phenocrysts of the host chondrules. Only the FeO-rich chondrule shows a resolvable excesses of 26Mg, corresponding to an inferred initial 26Al/27Al ratio [(26Al/27Al)0] of (2.5 ± 1.6) × 10-6 (±2SE). Combining these results with the previously reported Al-Mg isotope systematics of CR chondrules (Nagashima et al., 2014, Geochem. J. 48, 561), 7 of 22 chondrules (32%) measured show resolvable excesses of 26Mg; the presence of excess 26Mg does not correlate with the FeO content of chondrule silicates. In contrast, virtually all chondrules in weakly metamorphosed (petrologic type 3.0-3.1) unequilibrated ordinary chondrites (UOCs), Ornans-like carbonaceous (CO) chondrites, and the ungrouped carbonaceous chondrite Acfer 094 show resolvable excesses of 26Mg. The inferred (26Al/27Al)0 in CR chondrules with resolvable excesses of 26Mg range from (1.0 ± 0.4) × 10-6 to (6.3 ± 0.9) × 10-6, which is typically lower than (26Al/27Al)0 in the majority of chondrules from UOCs, COs, and Acfer 094. Based on the inferred (26Al/27Al)0, three populations of CR chondrules are recognized; the population characterized by low (26Al/27Al)0 (<3 × 10-6) is dominant. There are no noticeable trends with major and minor element or O-isotope compositions between these populations. The weighted mean (26Al/27Al)0 of 22 CR chondrules measured is (1.8 ± 0.3) × 10-6. An apparent agreement between the 26Al-26Mg ages (using weighted mean value) and the revised (using 238U/235U ratio for bulk CR chondrites of 137.7789 ± 0.0085) 207Pb-206Pb age of a set of chondrules from CR chondrites (Amelin et al., 2002, Science297, 1678) is consistent with the initial 26Al/27Al ratio in the CR chondrite chondrule-forming region at the canonical level (∼5.2 × 10-5), allowing the use of 26Al-26Mg systematics as a chronometer for CR chondrules. To prove chronological significance of 26Al for CR chondrules, measurements of Al-Mg and U-Pb isotope systematics on individual chondrules are required. The presence of several generations among CR chondrules indicates some chondrules that accreted into the CR chondrite parent asteroid avoided melting by later chondrule-forming events, suggesting chondrule-forming processes may have occurred on relatively limited spatial scales. Accretion of the CR chondrite parent body occurred at >4.0-0.3+0.5 Ma after the formation of CAIs with the canonical 26Al/27Al ratio, although rapid accretion after formation of the major population of CR chondrules is not required by our data.

Fermented dairy products modulate Citrobacter rodentium-induced colonic hyperplasia.

PubMed

Collins, James W; Chervaux, Christian; Raymond, Benoit; Derrien, Muriel; Brazeilles, Rémi; Kosta, Artemis; Chambaud, Isabelle; Crepin, Valerie F; Frankel, Gad

2014-10-01

We evaluated the protective effects of fermented dairy products (FDPs) in an infection model, using the mouse pathogen Citrobacter rodentium (CR). Treatment of mice with FDP formulas A, B, and C or a control product did not affect CR colonization, organ specificity, or attaching and effacing lesion formation. Fermented dairy product A (FDP-A), but neither the supernatant from FDP-A nor β-irradiated (IR) FDP-A, caused a significant reduction in colonic crypt hyperplasia and CR-associated pathology. Profiling the gut microbiota revealed that IR-FDP-A promoted higher levels of phylotypes belonging to Alcaligenaceae and a decrease in Lachnospiraceae (Ruminococcus) during CR infection. Conversely, FDP-A prevented a decrease in Ruminococcus and increased Turicibacteraceae (Turicibacter). Importantly, loss of Ruminococcus and Turicibacter has been associated with susceptibility to dextran sodium sulfate-induced colitis. Our results demonstrate that viable bacteria in FDP-A reduced CR-induced colonic crypt hyperplasia and prevented the loss of key bacterial genera that may contribute to disease pathology. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America.

Corrosion behavior of high-strength spring steel for high-speed railway

NASA Astrophysics Data System (ADS)

Niu, Gang; Chen, Yin-li; Wu, Hui-bin; Wang, Xuan; Tang, Di

2018-05-01

The corrosion resistance and evolution of corrosion products in medium-carbon high-strength spring steels were investigated in a neutral salt spray (5wt% NaCl solution). A formation model of γ-FeOOH and a transformation model describing the conversion of γ-FeOOH to α-FeOOH were constructed. The results indicated that, at the initial corrosion stage, the corrosion resistance was gradually improved with the addition of Cr; however, with the addition of alloying element V, the corrosion resistance decreased. These results were attributed mainly to the initial corrosion stage being closely related to the matrix microstructure parameters such as grain-boundary character and dislocation density. After the rust layer was formed at a later corrosion stage, the corrosion resistance was reinforced with the addition of Cr and V because Cr strongly influenced the composition, structure, and morphology of the corrosion products. The results presented herein show that Cr was conducive to the transformation of γ-FeOOH into α-FeOOH. Moreover, V and Cr exhibited obvious synergy and were enriched in the inner layer of the corrosion products.

Significant Axial Elongation with Minimal Change in Refraction in 3- to 6-Year-Old Chinese Preschoolers: The Shenzhen Kindergarten Eye Study.

PubMed

Guo, Xinxing; Fu, Min; Ding, Xiaohu; Morgan, Ian G; Zeng, Yangfa; He, Mingguang

2017-12-01

To document the distribution of ocular biometry and to evaluate its associations with refraction in a group of Chinese preschoolers. Population-based cross-sectional study. A total of 1133 preschoolers 3 to 6 years of age from 8 representative kindergartens. Biometric measurements including axial length (AL), anterior chamber depth (ACD), and corneal radius of curvature (CR) were obtained from partial-coherence laser interferometry (IOL Master; Carl Zeiss Meditec, Oberkochen, Germany) before cycloplegia. Lens power (LP) and AL-to-CR ratio were calculated. Cycloplegic refraction (3 drops of 1% cyclopentolate) was measured using an autorefractor (KR8800; Topcon Corp., Tokyo, Japan), and spherical equivalent refraction (SER) was calculated. Biometric and refractive parameters were assessed as a function of age and gender. Multiple regression analysis was performed to explore the associations between refraction and ocular biometry. Ocular biometric distributions and their relationships to refraction. Among the 1127 children (99.5%) with successful cycloplegic refraction, mean SER was 1.37±0.63 diopters (D). Prevalence of myopia increased from 0% at 3 years of age to 3.7% (95% confidence interval, 1.0%-6.5%) at 6 years of age. Biometric parameters followed Gaussian distributions with means of 22.39±0.68 mm for AL, 7.79±0.25 mm for CR, and 24.61±1.42 D for calculated LP; and non-Gaussian distributions with means of 3.34±0.24 mm for ACD and 2.88±0.06 for AL-to-CR ratio. Axial length, ACD, and AL-to-CR ratio increased from 3 to 6 years of age, CR remained stable, whereas LP declined. Overall, SER declined slightly. For the SER variance, AL explained 18.6% and AL-to-CR ratio explained 39.8%, whereas AL, CR, and LP accounted for 80.0% after adjusting for age and gender. Young Chinese children are predominantly mildly hyperopic, with a low prevalence of myopia by the age of 6 years. An increase of 1 mm in AL was associated with only 0.45 D of myopic change. Decreases in LP reduce the myopic shifts that normally would be associated with increases in AL, and thus play a key role in refractive development in this age group. Copyright © 2017 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Nature of the impactor at the K/T boundary: clues from Os, W and Cr isotopes.

NASA Astrophysics Data System (ADS)

Quitté, G.; Robin, E.; Capmas, F.; Levasseur, S.; Rocchia, R.; Birck, J. L.; Allègre, C. J.

2003-04-01

We measured the isotope composition of Os, W and Cr in K/T boundary sediments of three marine sites (Stevns Klint, Caravaca and Bidart) to determine the nature of the bolid that impacted the Earth 65 Myrs ago. We also analysed Ni-rich cosmic spinels, because they are thought to keep the signature of the impactor. The low REE content in spinels precludes indeed the hypothesis of a mixing with more than 10% of terrestrial material. The Os and W enrichment at the K/T boundary could be explained by a scavenging of chalcophile elements at the time of sulfide precipitation. The 187Os/186Os ratio of the K/T sediments is higher than the ratio of any kind of meteorites. On top of a possible mixing with surrounding sediments, we suggest that the boundary contained more Re in the past (lost since that time by alteration and oxidation) and that the Os isotope ratio is in fact disturbed. On each of the three sites, the boundary itself does not present any tungsten isotopic anomaly. The most likely interpretation is that the extraterrestrial material is diluted enough into the sediments so that the isotopic signature has been erased. Spinels show a small deficit of (0.34±0.9) ɛ in 182W. The large error bar precludes any clear conclusion whether or not a meteoritic signature is really present. If the spinels really carry an extraterrestrial signature as expected, their W composition is in favour of an ordinary chondrite. All K/T samples (sediments and spinels) are apparently depleted in 53Cr by about 0.5 ɛ (after renormalization of 54Cr to the terrestrial value) whereas ordinary chondrites display an excess of about 0.5 ɛ. Among meteorites, only carbonaceous chondrites present a negative value for the 53Cr/52Cr ratio relative to the terrestrial value. As more than 90% of the Cr present in spinels is of extraterrestrial origin, the Cr isotopes unambiguously show that the K/T impactor was a carbonaceous chondrite. These isotopic results also confirm the extraterrestrial origin of spinels. The W isotope composition of the spinels does not fully agree with the conclusion of a carbonaceous chondrite, but a refined measurement is required to discuss this discrepancy in more details.

Oxidation of Cr(III)-Fe(III) Mixed-phase Hydroxides by Chlorine: Implications on the Control of Hexavalent Chromium in Drinking Water.

PubMed

Chebeir, Michelle; Liu, Haizhou

2018-05-17

The occurrence of chromium (Cr) as an inorganic contaminant in drinking water is widely reported. One source of Cr is its accumulation in iron-containing corrosion scales of drinking water distribution systems as Cr(III)-Fe(III) hydroxide, i.e., FexCr(1-x)(OH)3(s), where x represents the Fe(III) molar content and typically varies between 0.25 and 0.75. This study investigated the kinetics of inadvertent hexavalent chromium Cr(VI) formation via the oxidation of FexCr(1-x)(OH)3(s) by chlorine as a residual disinfectant in drinking water, and examined the impacts of Fe(III) content and drinking water chemical parameters including pH, bromide and bicarbonate on the rate of Cr(VI) formation. Data showed that an increase in Fe(III) molar content resulted in a significant decrease in the stoichiometric Cr(VI) yield and the rate of Cr(VI) formation, mainly due to chlorine decay induced by Fe(III) surface sites. An increase in bicarbonate enhanced the rate of Cr(VI) formation, likely due to the formation of Fe(III)-carbonato surface complexes that slowed down the scavenging reaction with chlorine. The presence of bromide significantly accelerated the oxidation of FexCr(1-x)(OH)3(s) by chlorine, resulting from the catalytic effect of bromide acting as an electron shuttle. A higher solution pH between 6 and 8.5 slowed down the oxidation of Cr(III) by chlorine. These findings suggested that the oxidative conversion of chromium-containing iron corrosion products in drinking water distribution systems can lead to the occurrence of Cr(VI) at the tap, and the abundance of iron, and a careful control of pH, bicarbonate and bromide levels can assist the control of Cr(VI) formation.

Effect of Si Content on Oxide Formation on Surface of Molten Fe-Cr-C Alloy Bath During Oxygen Top Blowing

NASA Astrophysics Data System (ADS)

Mihara, Ryosuke; Gao, Xu; Kim, Sun-joong; Ueda, Shigeru; Shibata, Hiroyuki; Seok, Min Oh; Kitamura, Shin-ya

2018-02-01

Using a direct observation experimental method, the oxide formation behavior on the surface of Fe-Cr-5 mass pct C-Si alloy baths during decarburization by a top-blown Ar-O2 mixture was studied. The effects of the initial Si and Cr content of the alloy, temperature, and oxygen feed ratio on oxide formation were investigated. The results showed that, for alloys without Si, oxide particles, unstable oxide films, and stable oxide films formed sequentially. The presence of Si in the alloy changed the formation behavior of stable oxide film, and increased the crucial C content when stable oxide film started to form. Increasing the temperature, decreasing the initial Cr content, and increasing the ratio of the diluting gas decreased the critical C content at which a stable oxide film started to form. In addition, the P CO and a_{{{Cr}2 {O}3 }} values at which oxides started to form were estimated using Hilty's equation and the equilibrium relation to understand the formation conditions and the role of each parameter in oxide formation.

3D Simulations of NIF Wetted Foam Experiments to Understand the Transition from 2D to 3D Implosion Behavior

NASA Astrophysics Data System (ADS)

Haines, Brian; Olson, Richard; Yi, Austin; Zylstra, Alex; Peterson, Robert; Bradley, Paul; Shah, Rahul; Wilson, Doug; Kline, John; Leeper, Ramon; Batha, Steve

2017-10-01

The high convergence ratio (CR) of layered Inertial Confinement Fusion capsule implosions contribute to high performance in 1D simulations yet make them more susceptible to hydrodynamic instabilities, contributing to the development of 3D flows. The wetted foam platform is an approach to hot spot ignition to achieve low-to-moderate convergence ratios in layered implosions on the NIF unobtainable using an ice layer. Detailed high-resolution modeling of these experiments in 2D and 3D, including all known asymmetries, demonstrates that 2D hydrodynamics explain capsule performance at CR 12 but become less suitable as the CR increases. Mechanisms for this behavior and detailed comparisons of simulations to experiments on NIF will be presented. To evaluate the tradeoff between increased instability and improved 1D performance, we present a full-scale wetted foam capsule design with 17

Long-term osseointegration of 3D printed CoCr constructs with an interconnected open-pore architecture prepared by electron beam melting.

PubMed

Shah, Furqan A; Omar, Omar; Suska, Felicia; Snis, Anders; Matic, Aleksandar; Emanuelsson, Lena; Norlindh, Birgitta; Lausmaa, Jukka; Thomsen, Peter; Palmquist, Anders

2016-05-01

In orthopaedic surgery, cobalt chromium (CoCr) based alloys are used extensively for their high strength and wear properties, but with concerns over stress shielding and bone resorption due to the high stiffness of CoCr. The structural stiffness, principally related to the bulk and the elastic modulus of the material, may be lowered by appropriate design modifications, to reduce the stiffness mismatch between metal/alloy implants and the adjacent bone. Here, 3D printed CoCr and Ti6Al4V implants of similar macro-geometry and interconnected open-pore architecture prepared by electron beam melting (EBM) were evaluated following 26week implantation in adult sheep femora. Despite higher total bone-implant contact for Ti6Al4V (39±4%) than CoCr (27±4%), bone formation patterns were similar, e.g., densification around the implant, and gradual ingrowth into the porous network, with more bone in the outer half (periphery) than the inner half (centre). Raman spectroscopy revealed no major differences in mineral crystallinity, the apatite-to-collagen ratio, or the carbonate-to-phosphate ratio. Energy dispersive X-ray spectroscopy showed similar Ca/P ratio of the interfacial tissue adjacent to both materials. Osteocytes made direct contact with CoCr and Ti6Al4V. While osteocyte density and distribution in the new-formed bone were largely similar for the two alloys, higher osteocyte density was observed at the periphery of the porous network for CoCr, attributable to slower remodelling and a different biomechanical environment. The results demonstrate the possibility to achieve bone ingrowth into open-pore CoCr constructs, and attest to the potential for fabricating customised osseointegrated CoCr implants for load-bearing applications. Although cobalt chromium (CoCr) based alloys are used extensively in orthopaedic surgery, stress shielding due to the high stiffness of CoCr is of concern. To reduce the stiffness mismatch between CoCr and bone, CoCr and Ti6Al4V implants having an interconnected open-pore architecture were prepared by electron beam melting (EBM). After six months of submerged healing in sheep, both alloys showed similar patterns of bone formation, with densification around the implant and gradual ingrowth into the porous network. The molecular and elemental composition of the interfacial tissue was similar for both alloys. Osteocytes made direct contact with both alloys, with similar overall osteocyte density and distribution. The work attests to the potential for achieving osseointegration of EBM manufactured porous CoCr implants. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Navy Electroplating Pollution Control Technology Assessment Manual.

DTIC Science & Technology

1984-02-01

quality. Dummying of chromium baths is used in the special case where high cathode-to-anode 5ea ratio has resulted in build up of trivalent chromium (Cr...Dummying with a high anode -to-cat hode area ratio can be 6used to reoxidize the trivalent to hexavalent chromium (Cr ).Proper scheduling of work can...unit processes: * Chromium reduction (if needed) of segregated chromium waste streams to reduce the chromium from its hexavalent form to the trivalent

Effects of MC-Type Carbide Forming and Graphitizing Elements on Thermal Fatigue Behavior of Indefinite Chilled Cast Iron Rolls

NASA Astrophysics Data System (ADS)

Ahiale, Godwin Kwame; Choi, Won-Doo; Suh, Yongchan; Lee, Young-Kook; Oh, Yong-Jun

2015-11-01

The thermal fatigue behavior of indefinite chilled cast iron rolls with various V+Nb contents and Si/Cr ratios was evaluated. Increasing the ratio of Si/Cr prolonged the life of the rolls by reducing brittle cementites. Higher V+Nb addition also increased the life through the formation of carbides that refined and toughened the martensite matrix and reduced the thermal expansion mismatch in the microstructure.

High-precision Q EC values of superallowed 0 + → 0 + β-emitters 46Cr, 50Fe and 54Ni

DOE PAGES

Zhang, P.; Xu, X.; Shuai, P.; ...

2017-01-23

Short-lived 46Cr, 50Fe and 54Ni were studied by isochronous mass spectrometry at the HIRFL-CSR facility in Lanzhou. The measured precision mass excesses (ME) of 46Cr, 50Fe and 54Ni are -29471(11) keV, -34477(6) keV and -39278(4) keV, respectively. The superallowed 0 +→0+β-decay Q values were derived to be Q EC( 46Cr) =7604(11) keV, Q EC( 50Fe) =8150(6) keV and Q EC( 54Ni) =8731(4) keV. The values for 50Fe and 54Ni are by one order of magnitude more precise than the adopted literature values. By combining the existing half-lives and branching ratios, we obtained the corrected ℱt values to be ℱt(more » 50Fe) =3103(70) s and ℱt( 54Ni) =3076(50) s. The main contribution to the ℱt uncertainties is now due to β-decay branching ratios, still, more high-precision measurements of the half-lives, the masses, and especially the branching ratios are needed in order to satisfy the requirements for a stringent CVC test.« less

High-precision Q EC values of superallowed 0 + → 0 + β-emitters 46Cr, 50Fe and 54Ni

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

Zhang, P.; Xu, X.; Shuai, P.

Short-lived 46Cr, 50Fe and 54Ni were studied by isochronous mass spectrometry at the HIRFL-CSR facility in Lanzhou. The measured precision mass excesses (ME) of 46Cr, 50Fe and 54Ni are -29471(11) keV, -34477(6) keV and -39278(4) keV, respectively. The superallowed 0 +→0+β-decay Q values were derived to be Q EC( 46Cr) =7604(11) keV, Q EC( 50Fe) =8150(6) keV and Q EC( 54Ni) =8731(4) keV. The values for 50Fe and 54Ni are by one order of magnitude more precise than the adopted literature values. By combining the existing half-lives and branching ratios, we obtained the corrected ℱt values to be ℱt(more » 50Fe) =3103(70) s and ℱt( 54Ni) =3076(50) s. The main contribution to the ℱt uncertainties is now due to β-decay branching ratios, still, more high-precision measurements of the half-lives, the masses, and especially the branching ratios are needed in order to satisfy the requirements for a stringent CVC test.« less

Estimation of excess energies and activity coefficients for the penternary Ni-Cr-Co-Al-Mo system and its subsystems

NASA Astrophysics Data System (ADS)

Dogan, A.; Arslan, H.; Dogan, T.

2015-06-01

Using different prediction methods, such as the General Solution Model of Kohler and Muggianu, the excess energy and activities of molybdenum for the sections of the phase diagram for the penternary Ni-Cr-Co-Al-Mo system with mole ratios xNi/ xMo = 1, xCr/ xMo = 1, xCo/ xMo = 1, and xAl/ xMo = r = 0.5 and 1, were thermodynamically investigated at a temperature of 2000 K, whereas the excess energy and activities of Bi for the section corresponding to the ternary Bi-Ga-Sb system with mole ratio xGa/ xSb = 1/9 were thermodynamically investigated at a temperature of 1073 K. In the case of r = 0.5 and 1 in the alloys Ni-Cr-Co-Al-Mo, a positive deviation in the activity coefficient was revealed, as molybdenum content increased. Moreover, in the calculations performed in Chou's GSM model, the obtained values for excess Gibbs energies are negative in the whole concentration range of bismuth at 1073 K and exhibit the minimum of about -2.2 kJ/mol at the mole ratio xGa/ xSb = 1/9 in the alloy Bi-Ga-Sb.

Optical diagnostics with radiation trapping effect in low density and low temperature helium plasma

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

Lee, Wonwook, E-mail: wwlee@kaeri.re.kr; Kwon, Duck-Hee; Park, Kyungdeuk

2016-06-15

Low density (n{sub e} < 10{sup 11 }cm{sup −3}) and low temperature (T{sub e} < 10 eV) helium plasma was generated by hot filament discharge. Electron temperature and density of neutral helium plasma were measured by Langmuir probe and were determined by line intensity ratio method using optical emission spectroscopy with population modelings. Simple corona model and collisional-radiative (CR) model without consideration for radiation trapping effect are applied. In addition, CR model taking into account the radiation trapping effect (RTE) is adopted. The change of single line intensity ratio as a function of electron temperature and density were investigated when the RTE is included and excluded.more » The changes of multi line intensity ratios as a function of electron temperature were scanned for various radiative-excitation rate coefficients from the ground state and the helium gas pressures related with the RTE. Our CR modeling with RTE results in fairly better agreement of the spectroscopic diagnostics for the plasma temperature or density with the Langmuir probe measurements for various helium gas pressures than corona modeling and CR modeling without RTE.« less

An optimally evolved connective ratio of neural networks that maximizes the occurrence of synchronized bursting behavior

PubMed Central

2012-01-01

Background Synchronized bursting activity (SBA) is a remarkable dynamical behavior in both ex vivo and in vivo neural networks. Investigations of the underlying structural characteristics associated with SBA are crucial to understanding the system-level regulatory mechanism of neural network behaviors. Results In this study, artificial pulsed neural networks were established using spike response models to capture fundamental dynamics of large scale ex vivo cortical networks. Network simulations with synaptic parameter perturbations showed the following two findings. (i) In a network with an excitatory ratio (ER) of 80-90%, its connective ratio (CR) was within a range of 10-30% when the occurrence of SBA reached the highest expectation. This result was consistent with the experimental observation in ex vivo neuronal networks, which were reported to possess a matured inhibitory synaptic ratio of 10-20% and a CR of 10-30%. (ii) No SBA occurred when a network does not contain any all-positive-interaction feedback loop (APFL) motif. In a neural network containing APFLs, the number of APFLs presented an optimal range corresponding to the maximal occurrence of SBA, which was very similar to the optimal CR. Conclusions In a neural network, the evolutionarily selected CR (10-30%) optimizes the occurrence of SBA, and APFL serves a pivotal network motif required to maximize the occurrence of SBA. PMID:22462685

Predicting the outcome of grade II glioma treated with temozolomide using proton magnetic resonance spectroscopy.

PubMed

Guillevin, R; Menuel, C; Taillibert, S; Capelle, L; Costalat, R; Abud, L; Habas, C; De Marco, G; Hoang-Xuan, K; Chiras, J; Vallée, J-N

2011-06-07

This study was designed to evaluate proton magnetic resonance spectroscopy ((1)H-MRS) for monitoring the WHO grade II glioma (low-grade glioma (LGG)) treated with temozolomide (TMZ). This prospective study included adult patients with progressive LGG that was confirmed by magnetic resonance imaging (MRI). Temozolomide was administered at every 28 days. Response to TMZ was evaluated by monthly MRI examinations that included MRI with volumetric calculations and (1)H-MRS for assessing Cho/Cr and Cho/NAA ratios. Univariate, multivariate and receiver-operating characteristic statistical analyses were performed on the results. A total of 21 LGGs from 31 patients were included in the study, and followed for at least n=14 months during treatment. A total of 18 (86%) patients experienced a decrease in tumour volume with a greater decrease of metabolic ratios. Subsequently, five (28%) of these tumours resumed growth despite the continuation of TMZ administration with an earlier increase of metabolic ratios of 2 months. Three (14%) patients did not show any volume or metabolic change. The evolutions of the metabolic ratios, mean(Cho/Cr)(n) and mean(Cho/NAA)(n), were significantly correlated over time (Spearman ρ=+0.95) and followed a logarithmic regression (P>0.001). The evolutions over time of metabolic ratios, mean(Cho/Cr)(n) and mean(Cho/NAA)(n), were significantly correlated with the evolution of the mean relative decrease of tumour volume, mean(ΔV(n)/V(o)), according to a linear regression (P<0.001) in the 'response/no relapse' patient group, and with the evolution of the mean tumour volume (meanV(n)), according to an exponential regression (P<0.001) in the 'response/relapse' patient group. The mean relative decrease of metabolic ratio, mean(Δ(Cho/Cr)(n)/(Cho/Cr)(o)), at n=3 months was predictive of tumour response over the 14 months of follow-up. The mean relative change between metabolic ratios, mean((Cho/NAA)(n)-(Cho/Cr)(n))/(Cho/NAA)(n), at n=4 months was predictive of tumour relapse with a significant cutoff of 0.046, a sensitivity of 60% and a specificity of 100% (P=0.004). The (1)H-MRS profile changes more widely and rapidly than tumour volume during the response and relapse phases, and represents an early predictive factor of outcome over 14 months of follow-up. Thus, (1)H-MRS may be a promising, non-invasive tool for predicting and monitoring the clinical response to TMZ.

Predicting the outcome of grade II glioma treated with temozolomide using proton magnetic resonance spectroscopy

PubMed Central

Guillevin, R; Menuel, C; Taillibert, S; Capelle, L; Costalat, R; Abud, L; Habas, C; De Marco, G; Hoang-Xuan, K; Chiras, J; Vallée, J-N

2011-01-01

Background: This study was designed to evaluate proton magnetic resonance spectroscopy (1H-MRS) for monitoring the WHO grade II glioma (low-grade glioma (LGG)) treated with temozolomide (TMZ). Methods: This prospective study included adult patients with progressive LGG that was confirmed by magnetic resonance imaging (MRI). Temozolomide was administered at every 28 days. Response to TMZ was evaluated by monthly MRI examinations that included MRI with volumetric calculations and 1H-MRS for assessing Cho/Cr and Cho/NAA ratios. Univariate, multivariate and receiver-operating characteristic statistical analyses were performed on the results. Results: A total of 21 LGGs from 31 patients were included in the study, and followed for at least n=14 months during treatment. A total of 18 (86%) patients experienced a decrease in tumour volume with a greater decrease of metabolic ratios. Subsequently, five (28%) of these tumours resumed growth despite the continuation of TMZ administration with an earlier increase of metabolic ratios of 2 months. Three (14%) patients did not show any volume or metabolic change. The evolutions of the metabolic ratios, mean(Cho/Cr)n and mean(Cho/NAA)n, were significantly correlated over time (Spearman ρ=+0.95) and followed a logarithmic regression (P>0.001). The evolutions over time of metabolic ratios, mean(Cho/Cr)n and mean(Cho/NAA)n, were significantly correlated with the evolution of the mean relative decrease of tumour volume, mean(ΔVn/Vo), according to a linear regression (P<0.001) in the ‘response/no relapse' patient group, and with the evolution of the mean tumour volume (meanVn), according to an exponential regression (P<0.001) in the ‘response/relapse' patient group. The mean relative decrease of metabolic ratio, mean(Δ(Cho/Cr)n/(Cho/Cr)o), at n=3 months was predictive of tumour response over the 14 months of follow-up. The mean relative change between metabolic ratios, mean((Cho/NAA)n−(Cho/Cr)n)/(Cho/NAA)n, at n=4 months was predictive of tumour relapse with a significant cutoff of 0.046, a sensitivity of 60% and a specificity of 100% (P=0.004). Conclusions: The 1H-MRS profile changes more widely and rapidly than tumour volume during the response and relapse phases, and represents an early predictive factor of outcome over 14 months of follow-up. Thus, 1H-MRS may be a promising, non-invasive tool for predicting and monitoring the clinical response to TMZ. PMID:21610707

Application of a protocol for magnetic resonance spectroscopy of adrenal glands: an experiment with over 100 cases.

PubMed

Melo, Homero José de Farias E; Goldman, Suzan M; Szejnfeld, Jacob; Faria, Juliano F; Huayllas, Martha K P; Andreoni, Cássio; Kater, Cláudio E

2014-01-01

To evaluate a protocol for two-dimensional (2D) hydrogen proton (1H) magnetic resonance spectroscopy (MRS) (Siemens Medical Systems; Erlangen, Germany) in the detection of adrenal nodules and differentiation between benign and malignant masses (adenomas, pheochromocytomas, carcinomas and metastases). A total of 118 patients (36 men; 82 women) (mean age: 57.3 ± 13.3 years) presenting with 138 adrenal nodules/masses were prospectively assessed. A multivoxel system was utilized with a 2D point-resolved spectroscopy/chemical shift imaging sequence. The following ratios were calculated: choline (Cho)/creatine (Cr), 4.0-4.3/Cr, lipid (Lip)/Cr, Cho/Lip and lactate (Lac)/Cr. 2D-1H-MRS was successful in 123 (89.13%) lesions. Sensitivity and specificity values observed for the ratios and cutoff points were the following: Cho/Cr ≥ 1.2, 100% sensitivity, 98.2% specificity (differences between adenomas/pheochromocytomas and carcinomas/ metastases); 4.0-4.3 ppm/Cr ≥ 1.5, 92.3% sensitivity, 96.9% specificity (differences between carcinomas/pheochromocytomas and adenomas/metastases); Lac/Cr ≤ -7.449, 90.9% sensitivity and 77.8% specificity (differences between pheochromocytomas and carcinomas/adenomas). Information provided by 2D-1H-MRS were effective and allowed for the differentiation between adrenal masses and nodules in most cases of lesions with > 1.0 cm in diameter.

The effects of convergence ratio on the implosion behavior of DT layered inertial confinement fusion capsules

DOE PAGES

Haines, Brian M.; Yi, S. A.; Olson, R. E.; ...

2017-07-10

The wetted foam capsule design for inertial confinement fusion capsules, which includes a foam layer wetted with deuterium-tritium liquid, enables layered capsule implosions with a wide range of hot-spot convergence ratios (CR) on the National Ignition Facility. In this paper, we present a full-scale wetted foam capsule design that demonstrates high gain in one-dimensional simulations. In these simulations, increasing the convergence ratio leads to an improved capsule yield due to higher hot-spot temperatures and increased fuel areal density. High-resolution two-dimensional simulations of this design are presented with detailed and well resolved models for the capsule fill tube, support tent, surfacemore » roughness, and predicted asymmetries in the x-ray drive. Our modeling of these asymmetries is validated by comparisons with available experimental data. In 2D simulations of the full-scale wetted foam capsule design, jetting caused by the fill tube is prevented by the expansion of the tungsten-doped shell layer due to preheat. While the impacts of surface roughness and predicted asymmetries in the x-ray drive are enhanced by convergence effects, likely underpredicted in 2D at high CR, simulations predict that the capsule is robust to these features. Nevertheless, the design is highly susceptible to the effects of the capsule support tent, which negates all of the one-dimensional benefits of increasing the convergence ratio. Indeed, when the support tent is included in simulations, the yield decreases as the convergence ratio is increased for CR > 20. Finally and nevertheless, the results suggest that the full-scale wetted foam design has the potential to outperform ice layer capsules given currently achievable levels of asymmetries when fielded at low convergence ratios (CR < 20).« less

The Urinary Uric Acid/Creatinine Ratio is An Adjuvant Marker for Perinatal Asphyxia

PubMed Central

Bhongir, Aparna Varma; Yakama, Akhil Varma Venkata; Saha, Subhajit; Radia, Sejal B.; Pabbati, Jayalakshmi

2015-01-01

Objective To assess the urinary uric acid/creatinine ratio (UA/Cr) in relation to Apgar score and cord blood gas analysis in identification of perinatal asphyxia and to define the cutoff values. Design case control study. Setting The newborns admitted in the department of pediatrics and NICU of Mediciti Institute of Medical Science, Ghanpur, Medchal mandal, Telangana from May-July 2011 were enrolled. Participants/patients The study was conducted on 31 (18 males, 13 females) controls and 18 (12males, 6 females) asphyxiated neonates. Outcome Measure(s) 5ml of arterial cord blood of newborn collected at the time of birth and spot urine samples were collected within 24-72 hours of life. Cord blood gas analysis were done immediately and Urinary uric acid was measured by modified Uricase method, urinary creatinine by modified kinetic Jaffe's reaction. Results The mean urinary uric acid and creatinine ratio (2.58± 0.48 vs 1.89 ± 0.59) is significantly higher in Asphyxiated group than in the control group. The umbilical cord blood pH had significant positive correlation with 1st minute Apgar score (r= 0.41, p=0.003), 5th minute Apgar (r= 0.44, p=0.002), while urinary UA/Cr ratio had significant negative correlation with cord blood pH (r= -0.63, p=0.002). Urinary UA/Cr ratio with criterion of >2.43 had 80% sensitivity, 87.5% specificity with AUC of 0.84 (p=0.003) had a better predictive value. Conclusions Urinary UA/Cr ratio is easy, non-invasive, painless and economical adjuvant parameter with better predictive value for diagnosing perinatal asphyxia with simple diagnostic equipment. PMID:26998526

The effects of convergence ratio on the implosion behavior of DT layered inertial confinement fusion capsules

NASA Astrophysics Data System (ADS)

Haines, Brian M.; Yi, S. A.; Olson, R. E.; Khan, S. F.; Kyrala, G. A.; Zylstra, A. B.; Bradley, P. A.; Peterson, R. R.; Kline, J. L.; Leeper, R. J.; Shah, R. C.

2017-07-01

The wetted foam capsule design for inertial confinement fusion capsules, which includes a foam layer wetted with deuterium-tritium liquid, enables layered capsule implosions with a wide range of hot-spot convergence ratios (CR) on the National Ignition Facility. We present a full-scale wetted foam capsule design that demonstrates high gain in one-dimensional simulations. In these simulations, increasing the convergence ratio leads to an improved capsule yield due to higher hot-spot temperatures and increased fuel areal density. High-resolution two-dimensional simulations of this design are presented with detailed and well resolved models for the capsule fill tube, support tent, surface roughness, and predicted asymmetries in the x-ray drive. Our modeling of these asymmetries is validated by comparisons with available experimental data. In 2D simulations of the full-scale wetted foam capsule design, jetting caused by the fill tube is prevented by the expansion of the tungsten-doped shell layer due to preheat. While the impacts of surface roughness and predicted asymmetries in the x-ray drive are enhanced by convergence effects, likely underpredicted in 2D at high CR, simulations predict that the capsule is robust to these features. Nevertheless, the design is highly susceptible to the effects of the capsule support tent, which negates all of the one-dimensional benefits of increasing the convergence ratio. Indeed, when the support tent is included in simulations, the yield decreases as the convergence ratio is increased for CR > 20. Nevertheless, the results suggest that the full-scale wetted foam design has the potential to outperform ice layer capsules given currently achievable levels of asymmetries when fielded at low convergence ratios (CR < 20).

Selective hierarchical patterning of silicon nanostructures via soft nanostencil lithography

NASA Astrophysics Data System (ADS)

Du, Ke; Ding, Junjun; Wathuthanthri, Ishan; Choi, Chang-Hwan

2017-11-01

It is challenging to hierarchically pattern high-aspect-ratio nanostructures on microstructures using conventional lithographic techniques, where photoresist (PR) film is not able to uniformly cover on the microstructures as the aspect ratio increases. Such non-uniformity causes poor definition of nanopatterns over the microstructures. Nanostencil lithography can provide an alternative means to hierarchically construct nanostructures on microstructures via direct deposition or plasma etching through a free-standing nanoporous membrane. In this work, we demonstrate the multiscale hierarchical fabrication of high-aspect-ratio nanostructures on microstructures of silicon using a free-standing nanostencil, which is a nanoporous membrane consisting of metal (Cr), PR, and anti-reflective coating. The nanostencil membrane is used as a deposition mask to define Cr nanodot patterns on the predefined silicon microstructures. Then, deep reactive ion etching is used to hierarchically create nanostructures on the microstructures using the Cr nanodots as an etch mask. With simple modification of the main fabrication processes, high-aspect-ratio nanopillars are selectively defined only on top of the microstructures, on bottom, or on both top and bottom.

Electron-capture Isotopes Could Constrain Cosmic-Ray Propagation Models

NASA Astrophysics Data System (ADS)

Benyamin, David; Shaviv, Nir J.; Piran, Tsvi

2017-12-01

Electron capture (EC) isotopes are known to provide constraints on the low-energy behavior of cosmic rays (CRs), such as reacceleration. Here, we study the EC isotopes within the framework of the dynamic spiral-arms CR propagation model in which most of the CR sources reside in the galactic spiral arms. The model was previously used to explain the B/C and sub-Fe/Fe ratios. We show that the known inconsistency between the 49Ti/49V and 51V/51Cr ratios remains also in the spiral-arms model. On the other hand, unlike the general wisdom that says the isotope ratios depend primarily on reacceleration, we find here that the ratio also depends on the halo size (Z h) and, in spiral-arms models, also on the time since the last spiral-arm passage ({τ }{arm}). Namely, EC isotopes can, in principle, provide interesting constraints on the diffusion geometry. However, with the present uncertainties in the lab measurements of both the electron attachment rate and the fragmentation cross sections, no meaningful constraint can be placed.

Selective hierarchical patterning of silicon nanostructures via soft nanostencil lithography.

PubMed

Du, Ke; Ding, Junjun; Wathuthanthri, Ishan; Choi, Chang-Hwan

2017-11-17

It is challenging to hierarchically pattern high-aspect-ratio nanostructures on microstructures using conventional lithographic techniques, where photoresist (PR) film is not able to uniformly cover on the microstructures as the aspect ratio increases. Such non-uniformity causes poor definition of nanopatterns over the microstructures. Nanostencil lithography can provide an alternative means to hierarchically construct nanostructures on microstructures via direct deposition or plasma etching through a free-standing nanoporous membrane. In this work, we demonstrate the multiscale hierarchical fabrication of high-aspect-ratio nanostructures on microstructures of silicon using a free-standing nanostencil, which is a nanoporous membrane consisting of metal (Cr), PR, and anti-reflective coating. The nanostencil membrane is used as a deposition mask to define Cr nanodot patterns on the predefined silicon microstructures. Then, deep reactive ion etching is used to hierarchically create nanostructures on the microstructures using the Cr nanodots as an etch mask. With simple modification of the main fabrication processes, high-aspect-ratio nanopillars are selectively defined only on top of the microstructures, on bottom, or on both top and bottom.

Effect of 0.25 and 2.0 MeV He-Ion Irradiation on Short-Range Ordering in Model (EFDA) Fe-Cr Alloys

NASA Astrophysics Data System (ADS)

Dubiel, Stanisław M.; Żukrowski, Jan; Serruys, Yves

2018-05-01

The effects of He+ irradiation on a distribution of Cr atoms in Fe100-x Cr x (x = 5.8, 10.75, 15.15) alloys were studied by 57Fe Conversion Electron Mössbauer Spectroscopy (CEMS). The alloys were irradiated with doses up to 12 × 1016 ions/cm2 with 0.25 and 2.0 MeV He+ ions. The distribution of Cr atoms within the first two coordination shells around Fe atoms was expressed with short-range order parameters α 1 (first-neighbor shell, 1NN), α 2 (second-neighbor shell, 2NN), and α 12 (1NN + 2NN). In non-irradiated alloys, α 1 >0 and α 2 <0 was revealed for all three samples. The value of α 12 ≈0, i.e., the distribution of Cr atoms averaged over 1NN and 2NN, was random. The effect of the irradiation of the Fe94.2Cr5.8 alloy was similar for the two energies of He+, viz., increase of number of Cr atoms in 1NN and decrease in 2NN. Consequently, the degree of ordering increased. For the other two samples, the effect of the irradiation depends on the composition, and is stronger for the less energetic ions where, for Fe89.25Cr10.75 alloy, the disordering disappeared and some traces of Cr clustering appeared. In Fe84.85Cr15.15 alloy, the clustering was clear. In the samples irradiated with 2. 0 MeV He+ ions, the ordering also survived in the samples with x = 10.75 and 15.15, yet its degree became smaller than in the Fe94.2Cr5.8 alloy.

CR108, a novel vitamin K3 derivative induces apoptosis and breast tumor inhibition by reactive oxygen species and mitochondrial dysfunction.

PubMed

Yang, Chun-Ru; Liao, Wei-Siang; Wu, Ya-Hui; Murugan, Kaliyappan; Chen, Chinpiao; Chao, Jui-I

2013-12-15

Vitamin K3 derivatives have been shown to exert anticancer activities. Here we show a novel vitamin K3 derivative (S)-2-(2-hydroxy-3-methylbutylthio)naphthalene-1,4-dione, which is named as CR108 that induces apoptosis and tumor inhibition through reactive oxygen species (ROS) and mitochondrial dysfunction in human breast cancer. CR108 is more effective on the breast cancer cell death than other vitamin K3 derivatives. Moreover, CR108 induced apoptosis in both the non-HER-2-overexpressed MCF-7 and HER-2-overexpressed BT-474 breast cancer cells. CR108 caused the loss of mitochondrial membrane potential, cytochrome c released from mitochondria to cytosol, and cleaved PARP proteins for apoptosis induction. CR108 markedly increased ROS levels in breast cancer cells. N-acetylcysteine (NAC), a general ROS scavenger, completely blocked the CR108-induced ROS levels, mitochondrial dysfunction and apoptosis. Interestingly, CR108 increased the phosphorylation of p38 MAP kinase but conversely inhibited the survivin protein expression. NAC treatment prevented the activation of p38 MAP kinase and rescued the survivin protein levels. SB202190, a specific p38 MAP kinase inhibitor, recovered the survivin protein levels and attenuated the cytotoxicity of CR108-treated cells. Furthermore, CR108 inhibited the xenografted human breast tumor growth in nude mice. Together, we demonstrate that CR108 is a novel vitamin K3 derivative that induces apoptosis and tumor inhibition by ROS production and mitochondrial dysfunction and associates with the phosphorylation of p38 MAP kinase and the inhibition of survivin in the human breast cancer. © 2013.

Contributors to chromium isotope variation of meteorites

NASA Astrophysics Data System (ADS)

Qin, Liping; Alexander, Conel M. O.'D.; Carlson, Richard W.; Horan, Mary F.; Yokoyama, Tetsuya

2010-02-01

We report the results of a comprehensive, high precision survey of the Cr isotopic compositions of primitive chondrites, along with some differentiated meteorites. To ensure complete dissolution of our samples, they were first fused with lithium borate-tetraborate at 1050-1000 °C. Relative to the NIST Cr standard SRM 3112a, carbonaceous chondrites exhibit excesses in 54Cr/ 52Cr from 0.4 to 1.6 ɛ (1 ɛ = 1 part in 10,000), and ordinary chondrites display a common 54Cr/ 52Cr deficit of ˜0.4 ɛ. Analyses of acid-digestion residues of chondrites show that carbonaceous and ordinary chondrites share a common 54Cr-enriched carrier, which is characterized by a large excess in 54Cr/ 52Cr (up to 200 ɛ) associated with a very small deficit in 53Cr/ 52Cr (<2 ɛ). We did not find 54Cr anomalies in either bulk enstatite chondrites or in leachates of their acid-digestion residues. This either requires that the enstatite chondrite parent bodies did not incorporate the 54Cr anomaly carrier phase during their accretion, or the phase was destroyed by parent body metamorphism. Chromium in the terrestrial rocks and lunar samples analyzed here show no deviation from the NIST SRM 3112a Cr standard. The eucrite and Martian meteorites studied exhibit small deficits in 54Cr/ 52Cr. The 54Cr/ 52Cr variations among different meteorite classes suggest that there was a spatial and/or temporal heterogeneity in the distribution of a 54Cr-rich component in the inner Solar System. We confirm the correlated excesses in 54Cr/ 52Cr and 53Cr/ 52Cr for bulk carbonaceous chondrites, but the new data yield a steeper slope (˜6.6) than that reported in Shukolyukov and Lugmair (2006). The correlated excesses may affect the use of the Mn-Cr chronometer in carbonaceous chondrites. We could not confirm the bulk carbonaceous chondrite Mn-Cr isochron reported by Shukolyukov and Lugmair (2006) and Moynier et al. (2007), mostly because we find much smaller total variations in ɛ53Cr (˜0.2). All bulk chondrites have small ɛ53Cr excesses (up to 0.3) relative to the Earth, most likely reflecting the sub-chondritic Mn/Cr ratio of the Earth. The ɛ53Cr variations in chondrites do seem to grossly correlate with Mn/Cr and yield an initial Solar System 53Mn/ 55Mn value of 5.4(±2.4) × 10 -6, corresponding to an absolute age of 4566.4 (±2.2) Ma. Nuclear interactions with cosmic rays result in coupled excesses in ɛ54Cr and ɛ53Cr with a ˜4:1 ratio in phases with high Fe/Cr. These are most dramatically demonstrated in the iron meteorite Carbo, showing excesses in ɛ54Cr of up to 140 ɛ. These new results show that the Mn-Cr chronometer should be used with caution in samples/minerals with high Fe/Cr and long cosmic ray exposure ages.

Longitudinal changes in corneal curvature and its relationship to axial length in the Correction of Myopia Evaluation Trial (COMET) cohort.

PubMed

Scheiman, Mitchell; Gwiazda, Jane; Zhang, Qinghua; Deng, Li; Fern, Karen; Manny, Ruth E; Weissberg, Erik; Hyman, Leslie

2016-01-01

To describe longitudinal changes in corneal curvature (CC) and axial length (AL) over 14 years, and to explore the relationship between AL and CC, and the axial length/corneal radius (AL/CR) ratio. In total 469, 6 to <12-year-old, children were enrolled in COMET. Measurements of refractive error, CC (D), CR (mm), and ocular component dimensions including AL were gathered annually. Linear mixed models were used to evaluate longitudinal changes adjusting for covariates (gender, ethnicity, lens type, baseline age and baseline refraction). The Pearson correlation coefficient between AL and CC was computed at each visit. There was a slight but significant (p<0.0001) flattening in CC over 14 years. At all visits females had significantly steeper CC than males (overall difference=0.53 D, p<0.0001). Caucasians had the steepest CC, and Hispanics the flattest (p=0.001). The correlation between AL and CC was -0.70 (p<0.0001) at baseline (mean age=9.3 years) and decreased to -0.53 (p<0.0001) at the 14-year visit (mean age=24.1 years). The average AL/CR ratio was 3.15 at baseline and increased to 3.31 at the 14-year visit. The correlation between the magnitude of myopia and AL/CR ratio was significantly higher (p<0.0001) at each visit than the correlation between myopia and AL alone. Differences in average corneal curvature by age, gender, and ethnicity observed in early childhood remain consistent as myopia progresses and stabilizes. This study also demonstrates increases in the AL/CR ratio as myopia progresses and then stabilizes, supporting observations from previous cross-sectional data. Copyright © 2015 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

Morphology and stability in a half-metallic ferromagnetic CrO 2 compound of nanoparticles synthesized via a polymer precursor

NASA Astrophysics Data System (ADS)

Biswas, S.; Ram, S.

2004-11-01

Nanoparticles of stable CrO2 of a half-metallic ferromagnet are synthesized with a novel chemical method involving a Cr4+-polymer composite precursor. A single phase CrO2 of D4h 14 : P42 / mnm tetragonal crystal structure (lattice parameters a = 0.4250 and c = 0.3190 nm) lies after firing the precursor at 350 °C for 1 h in air. Microstructure reveals single domain CrO2 particles of thin platelets (aspect ratio ∼1) of average 50 nm diameter and 35 nm thickness. In air, unless heating at temperatures above 500 °C, no due CrO2 → Cr2O3 phase transformation encounters. The results are presented in terms of X-ray diffraction and thermal or thermogravimetric analysis of precursor and derived CrO2 powder.

Longitudinal cerebral metabolic changes in pig-tailed macaques infected with the neurovirulent virus SIVsmmFGb

PubMed Central

Li, Chun-Xia; Zhang, Xiaodong; Komery, Amelia; Li, Yingxia; Mao, Hui; Herndon, James G; Novembre, Francis J

2014-01-01

Longitudinal cerebral metabolite changes in pig-tailed macaques inoculated with the simian immunodeficiency virus SIVsmmFGb were evaluated with in vivo proton MRS at 3T. Blood sample collection, and MRS were carried out before and 2, 4, 8, 12, 16, 20 and 24 weeks after SIV inoculation. Significant reduction of N-acetylaspartate (NAA)/creatine (Cr) and Choline (Cho)/Cr ratios in prefrontal grey matter (PGM) and glutamate/glutamine (Glx)/Cr ratios in striatum, and increase of myo-inositol (mI)/Cr in striatum were observed during acute SIV infection. The metabolite alterations during the SIVsmmFGb infection are largely in agreement with previous findings in other non-human primate models and HIV patients. Also, NAA/Cr in PGM and striatum and Glx/Cr in striatum are negatively correlated with the percentage of CD8+ T cells after the SIV infection, suggesting the interaction between brain metabolite and immune dysfunction. The present study complements previous studies by describing the time course of alterations of brain metabolites during SIVsmmFGb infection. The findings further demonstrate the efficacy of the SIVsmmFGb-infected macaque as a model to characterize central nervous system infection using novel neuroimaging approaches and also as a tool for exploration of novel and advanced neuroimaging techniques in HIV/AIDS studies. PMID:25377443

Dramatic Improvement on Catalyst Loadings and Molar Ratios of Coupling Partners for Ni/Cr-Mediated Coupling Reactions: Heterobimetallic Catalysts

PubMed Central

Liu, Xiang; Henderson, James A.; Sasaki, Takeo; Kishi, Yoshito

2009-01-01

Two new ligands 1a,b have been reported. Upon treatment with one equivalent of NiCl2·(MeOCH2)2, 1a,b give the corresponding Ni-complexes. X-ray analysis of 1a·NiCl2 has established that the NiCl2 is selectively coordinated to the phenanthroline nitrogens. Ni/Cr-heterobimetallic catalysts 1a,b·CrCl2/NiCl2, prepared from 1a,b·NiCl2, have been shown to behave exceptionally well for the catalytic asymmetric Ni/Cr-mediated couplings, with the highlights including: (1) 1~2 mol % catalysts are sufficient to complete the coupling, (2) only a negligible amount of the dimers, by-products formed through the alkenyl Ni-species, is observed, (3) the coupling completes even with a 1:1 molar ratio of the coupling partners, and (4) the asymmetric induction is practically identical with that obtained in the coupling with the Cr-catalyst prepared from (S)-sulfonamide 2a,b. Using 4 additional aldehydes, a scope of the new Ni/Cr-heterobimetallic catalysts is briefly studied. Applicability of new catalysts to polyfunctional substrates has been demonstrated, with use of two C-C bond-formations chosen from the halichondrin/E7389 synthesis as examples. PMID:19874019

Longitudinal cerebral metabolic changes in pig-tailed macaques infected with the neurovirulent virus SIVsmmFGb.

PubMed

Li, Chun-Xia; Zhang, Xiaodong; Komery, Amelia; Li, Yingxia; Mao, Hui; Herndon, James G; Novembre, Francis J

2014-12-01

Longitudinal cerebral metabolite changes in pig-tailed macaques inoculated with the simian immunodeficiency virus SIVsmmFGb were evaluated with in vivo proton MRS at 3 T. Blood sample collection, and MRS were carried out before and 2, 4, 8, 12, 16, 20, and 24 weeks after SIV inoculation. Significant reduction of N-acetylaspartate (NAA)/creatine (Cr) and choline (Cho)/Cr ratios in prefrontal gray matter (PGM) and glutamate/glutamine(Glx)/Cr ratio in striatum, and increase of myo-inositol (mI)/Cr in striatum were observed during acute SIV infection. The metabolite alterations during the SIVsmmFGb infection are largely in agreement with previous findings in other non-human primate models and HIV patients. Also, NAA/Cr in PGM and striatum and Glx/Cr in striatum are negatively correlated with the percentage of CD8+ T cells after the SIV infection, suggesting the interaction between brain metabolite and immune dysfunction. The present study complements previous studies by describing the time course of alterations of brain metabolites during SIVsmmFGb infection. The findings further demonstrate the efficacy of the SIVsmmFGb-infected macaque as a model to characterize central nervous system infection using novel neuroimaging approaches and also as a tool for exploration of novel and advanced neuroimaging techniques in HIV/AIDS studies.

Isotopic, Chemical and Mineralogical Investigation's of Extraterrestrial Materials

NASA Technical Reports Server (NTRS)

Lugmair, G. W.

2003-01-01

During the grant period we have concentrated on the following main topics: 1. Enstatite meteorites and original heterogeneity of Mn-53 distribution in the solar nebula. We have completed our studies of the enstatite chondrites. 2. Processes of planetary differentiation. We have completed our study of silicate clasts from the mesosiderite Vaca Muerta and found that the global Mn/Cr fractionation event that established mantle source reservoirs on the parent body of the Vaca Muerta silicate clasts occurred approx. 2 Ma after a similar event on the howardite-eucrite-diogenite (HED) parent body. 3. Carbonaceous chondrites. Much effort has been devoted during the last three years to the investigation of this important class of meteorites. 4. Early solar system timescales. Based on the studies of the Mn-53 - Cr-53 isotope system in various meteorites and using results obtained with other isotope chronometers we constructed an absolute time-scale for events in the early solar system. 5.Unusual meteorites. We have studied the anomalous pallasite Eagle Station. 6. The chromium isotopic composition as a tracer for extraterrestrial material on Earth. Based on the observed difference in the Cr-53/Cr-52 ratios between Earth and the other solar system objects we developed a method for detecting cosmic materials on Earth using the Cr-53/Cr-52 ratio as a tracer.

Double Molecular Photoswitch Driven by Light and Collisions

NASA Astrophysics Data System (ADS)

Bull, James N.; Scholz, Michael S.; Carrascosa, Eduardo; da Silva, Gabriel; Bieske, Evan J.

2018-06-01

The shapes of many molecules can be transformed by light or heat. Here we investigate collision- and photon-induced interconversions of E E , E Z , and Z Z isomers of the isolated Congo red (CR) dianion, a double molecular switch containing two - N ═ N - azo groups, each of which can have the E or Z configuration. We find that collisional activation of CR dianions drives a one-way Z Z →E Z →E E cascade towards the lowest-energy isomer, whereas the absorption of a single photon over the 270-600 nm range can switch either azo group from E to Z or Z to E , driving the CR dianion to lower- or higher-energy forms. The experimental results, which are interpreted with the aid of calculated statistical isomerization rates, indicate that photoisomerization of CR in the gas phase involves a passage through conical intersection seams linking the excited and ground state potential energy surfaces rather than through isomerization on the ground state potential energy surface following internal conversion.

Variable convergence liquid layer implosions on the National Ignition Facility

NASA Astrophysics Data System (ADS)

Zylstra, A. B.; Yi, S. A.; Haines, B. M.; Olson, R. E.; Leeper, R. J.; Braun, T.; Biener, J.; Kline, J. L.; Batha, S. H.; Berzak Hopkins, L.; Bhandarkar, S.; Bradley, P. A.; Crippen, J.; Farrell, M.; Fittinghoff, D.; Herrmann, H. W.; Huang, H.; Khan, S.; Kong, C.; Kozioziemski, B. J.; Kyrala, G. A.; Ma, T.; Meezan, N. B.; Merrill, F.; Nikroo, A.; Peterson, R. R.; Rice, N.; Sater, J. D.; Shah, R. C.; Stadermann, M.; Volegov, P.; Walters, C.; Wilson, D. C.

2018-05-01

Liquid layer implosions using the "wetted foam" technique, where the liquid fuel is wicked into a supporting foam, have been recently conducted on the National Ignition Facility for the first time [Olson et al., Phys. Rev. Lett. 117, 245001 (2016)]. We report on a series of wetted foam implosions where the convergence ratio was varied between 12 and 20. Reduced nuclear performance is observed as convergence ratio increases. 2-D radiation-hydrodynamics simulations accurately capture the performance at convergence ratios (CR) ˜ 12, but we observe a significant discrepancy at CR ˜ 20. This may be due to suppressed hot-spot formation or an anomalous energy loss mechanism.

Multiple episodes of partial melting, depletion, metasomatism and enrichment processes recorded in the heterogeneous upper mantle sequence of the Neotethyan Eldivan ophiolite, Turkey

NASA Astrophysics Data System (ADS)

Uysal, Ibrahim; Ersoy, E. Yalçın; Dilek, Yildirim; Kapsiotis, Argyrios; Sarıfakıoğlu, Ender

2016-03-01

The Eldivan ophiolite along the Izmir-Ankara-Erzincan suture zone in north-central Anatolia represents a remnant of the Neotethyan oceanic lithosphere. Its upper mantle peridotites include three lithologically and compositionally distinct units: clinopyroxene (cpx)-harzburgite and lherzolite (Group-1), depleted harzburgite (Group-2), and dunite (Group-3). Relics of primary olivine and pyroxene occur in the less refractory harzburgites, and fresh chromian spinel (Cr-spinel) is ubiquitous in all peridotites. The Eldivan peridotites reflect a petrogenetic history evolving from relatively fertile (lherzolite and cpx-harzburgite) toward more depleted (dunite) compositions through time, as indicated by (i) a progressive decrease in the modal cpx distribution, (ii) a progressive increase in the Cr#s [Cr / (Cr + Al)] of Cr-spinel (0.15-0.78), and (iii) an increased depletion in the whole-rock abundances of some magmaphile major oxides (Al2O3, CaO, SiO2 and TiO2) and incompatible trace elements (Zn, Sc, V and Y). The primitive mantle-normalized REE patterns of the Group-1 and some of the Group-2 peridotites display LREE depletions. Higher YbN and lower SmN/YbN ratios of these rocks are compatible with their formation after relatively low degrees (9-25%) of open-system dynamic melting (OSDM) of a Depleted Mid-ocean ridge Mantle (DMM) source, which was then fluxed with small volumes of oceanic mantle-derived melt [fluxing ratio (β): 0.7-1.2%]. Accessory Cr-spinel compositions (Cr# = 015-0.53) of these rocks are consistent with their origin as residual peridotites beneath a mid-ocean ridge axis. Part of the Group-2 harzburgites exhibit lower YbN and higher SmN/YbN ratios, LREE-enriched REE patterns, and higher Cr-spinel Cr#s ranging between 0.54 and 0.61. Trace element compositions of these peridotites can be modeled by approximately 15% OSDM of a previously 17% depleted DMM, which was then fluxed (β: 0.4%) with subduction-influenced melt. The Group-3 dunite samples contain Cr-spinel with elevated Cr#s (0.73-0.78) and low-TiO2 contents (< 0.13 wt.%), implying higher degrees of melting (21-24%) of an already depleted DMM that was triggered by infiltration of low-Ti boninite melt with fluxing rates of 0.4-4.0%. The existence of interstitial, idiomorphic Cr-spinel (high Cr# and low Ti) in the Group-3 dunites is consistent with this interpretation. The occurrence of both MOR- and SSZ-type peridotites in the Eldivan ophiolite suggests that its heterogeneous upper mantle was produced as a result of different partial melting and melt-rock reaction processes in different tectonic settings within the Neotethyan realm.

Comparative analysis of the development of wing-flapping and flight in the fowl.

PubMed

Provine, R R; Strawbridge, C L; Harrison, B J

1984-01-01

The development of wing-flapping rate, lateral flight, wing area, and the ratio of wing area to body weight are described in the Japanese quail (Coturnix coturnix japonica) and three chickens (Gallus gallus) to determine common developmental phenomena and to assess the effects of domestication. The chickens were the White Leghorn (a commercial egg producer), the Cornish X Rock (a commercial meat producer), and the Red Jungle fowl (the probable ancestor of domestic chickens). All birds performed drop-evoked wing-flapping on the day of hatching, at least 1 week before lateral flight was possible. Flapping rate of chickens doubled between hatching (approximately 4-6 Hz) and 13 days (approximately 9-12 Hz), after which it leveled off. Japanese quail (JQ) maintained a high flapping rate (approximately 11-13 Hz) during the 21 days after hatching. The Jungle fowl (JF) and JQ flapped the fastest and the White Leghorn (WL) and Cornish X Rock (CR) chickens flapped the slowest. The JF, WL, and JQ developed lateral flight at 7-9 days. The CR first flew 1-2 weeks later but subsequently became flightless. The WL, JF, and JQ had similar ratios of wing area to body weight; the ratios increased to a peak at 11-15 days and later declined. The ratio of the very heavy, essentially flightless, CR was approximately one-half that of the flighted JQ, WL, and JF. The wing-flapping frequencies of the domestic WL and CR chickens approximated that of the JF, suggesting that domestication did not affect the motor pattern generator for flight. The artificial selection of the CR for high body weight drastically diminished its flight performance by producing an unfavorable ratio of wing area to body weight. The JF and the domestic WL both flew well and had similar ratios. Domestication affected flight performance but not the neural circuitry producing wing-flapping. The central nervous system is much more conservative in its response to selection than the peripheral effector structures that it drives.

Urinary NGAL, KIM-1 and L-FABP concentrations in antenatal hydronephrosis.

PubMed

Noyan, Aytul; Parmaksiz, Gonul; Dursun, Hasan; Ezer, Semire Serin; Anarat, Ruksan; Cengiz, Nurcan

2015-10-01

The clinical tests currently in use for obstructive nephropathy (such as renal ultrasonography, differential radionuclide renal scans and urinary creatinine concentration data) are not efficient predictors of the subsequent clinical course. Novel and simple biomarkers are required which, if proven, could be clinically beneficial in determining if a patient is eligible for surgery or reno-protective therapy. More recently, the interest of clinicians has focused on the potential of urinary neutrophil gelatinase-associated lipocalin (uNGAL), urinary kidney injury molecule-1 (uKIM-1) and urinary liver-type fatty acid-binding proteins (uL-FABP) as biomarkers for renal function in children with hydronephrosis (HN). The purpose of this study was to investigate possible clinical applications of uNGAL, uKIM-1 and uL-FABP as beneficial non-invasive biomarkers to determine whether or not surgical intervention is required in children with HN. Renal ultrasonography and radionuclide renal scans were used as diagnostic tools to detect HN. Patients were divided into two groups based on the antero-posterior diameter of their renal pelvis and the presence of dysfunction. Group 1 included 26 children with severe HN (with dysfunction), and group 2 consisted of 36 children with mild HN (without dysfunction). Urine samples were collected from 62 children with HN and 20 healthy children. Hydronephrosis was more common in males than in females, with a male to female ratio of 9:1 in the study sample. The incidence of left kidney involvement (32 patients) was slightly higher than right kidney involvement (28 patients). Compared with controls and group 2, the ratio of uNGAL to creatinine was significantly higher in group 1 (p < 0.05). The biomarker uNGAL/Cr exhibited fairly good diagnostic accuracy, with an area under the curve of 0.68 [95% confidence interval 0.6-0.7] and an optimal cut-off value of 0.16 ng/mg Cr (sensitivity 58%, specificity 75%) (p < 0.05). There was a positive correlation between the uNGAL/Cr ratio and the uKIM-1/Cr ratio (r = 0.582, p < 0.05) and uL-FABP/Cr ratio (r = 0675, p < 0.05) in group 1. The results clearly demonstrated that children with hydronephrosis and dysfunction had significantly increased uNGAL, and uNGAL/Cr concentrations. However, uKIM-1, uKIM-1/Cr, uL-FABP and uL-FABP/Cr concentrations were not significantly different when compared with controls. These results support the use of uNGAL concentrations as an early marker for renal dysfunction in HN. The study clearly demonstrated that pediatric patients with hydronephrosis and dysfunction had significantly higher uNGAL to creatinine concentrations as compared with controls. Copyright © 2015 Journal of Pediatric Urology Company. All rights reserved.

Caloric restriction counteracts age-related changes in the activities of sorbitol metabolizing enzymes from mouse liver

PubMed Central

Hagopian, Kevork; Ramsey, Jon J.; Weindruch, Richard

2009-01-01

The influence of caloric restriction (CR) on hepatic sorbitol-metabolizing enzyme activities was investigated in young and old mice. Aldose reductase and sorbitol dehydrogenase activities were significantly lower in old CR mice than in old controls. Young CR mice showed decreased aldose reductase activity and a trend towards decreased sorbitol dehydrogenase when compared to controls. Metabolites of the pathway, namely sorbitol, glucose and fructose were decreased by CR in young and old mice. Pyruvate levels were decreased by CR in both young and old mice, while lactate decreased only in old CR. Malate levels increased in old CR but remained unchanged in young CR, when compared with controls. Accordingly, the lactae/pyruvate and malate/pyruvate ratios in young and old CR mice were increased, indicating increased NADH/NAD and NADPH/NADP redox couples, respectively. The results indicate that decreased glucose levels under CR conditions lead to decreased sorbitol pathway enzyme activities and metabolite levels, and could contribute to the beneficial effects of long-term CR through decreased sorbitol levels and NADPH sparing. PMID:18953666

Compositional and isotopic heterogeneities in the Neo-Tethyan upper mantle recorded by coexisting Al-rich and Cr-rich chromitites in the Purang peridotite massif, SW Tibet (China)

NASA Astrophysics Data System (ADS)

Xiong, Fahui; Yang, Jingsui; Xu, Xiangzhen; Kapsiotis, Argyrios; Hao, Xiaolin; Liu, Zhao

2018-06-01

The Purang harzburgite massif in SW Tibet (China) hosts abundant chrome ore deposits. Ores consist of 20 to >95% modal chromian spinel (Cr-spinel) with mylonitic fabric in imbricate shaped pods. The composition of Cr-spinel in these ores ranges from Al-rich [Cr#Sp or Cr/(Cr + Al) × 100 = 47.60-57.56] to Cr-rich (Cr#Sp: 62.55-79.57). Bulk platinum-group element (PGE) contents of chromitites are also highly variable ranging from 17.5 ppb to ∼2.5 ppm. Both metallurgical and refractory chromitites show a general enrichment in the IPGE (Os, Ir and Ru) with respect to the PPGE (Rh, Pt and Pd), resulting mostly in right-sloping primitive mantle (PM)-normalized PGE profiles. The platinum-group mineral (PGM) assemblages of both chromitite types are dominated by heterogeneously distributed, euhedral Os-bearing laurite inclusions in Cr-spinel. The Purang chromitites have quite inhomogeneous 187Os/188Os ratios (0.12289-0.13194) that are within the range of those reported for mantle-hosted chromitites from other peridotite massifs. Geochemical calculations demonstrate that the parental melts of high-Cr chromitites were boninitic, whereas those of high-Al chromitites had an arc-type tholeiitic affinity. Chromite crystallization was most likely stimulated by changes in magma compositions due to melt-peridotite interaction, leading to the establishment of a heterogeneous physicochemical environment during the early crystallization of the PGM. The highly variable PGE contents, inhomogeneous Os-isotopic compositions and varying Cr#Sp ratios of these chromitites imply a polygenetic origin for them from spatially distinct melt inputs. The generally low γOs values (<1) of chromitites indicate that their parental melts originated within different sections of a heterogeneously depleted mantle source region. These melts were most likely produced in the mantle wedge above a downgoing lithospheric slab.

Effects of fluoxetine on the amygdala and the hippocampus after administration of a single prolonged stress to male Wistar rates: In vivo proton magnetic resonance spectroscopy findings.

PubMed

Han, Fang; Xiao, Bing; Wen, Lili; Shi, Yuxiu

2015-05-30

Posttraumatic stress disorder (PTSD) is an anxiety- and memory-based disorder. The hippocampus and amygdala are key areas in mood regulation. Fluoxetine was found to improve the anxiety-related symptoms of PTSD patients. However, little work has directly examined the effects of fluoxetine on the hippocampus and the amygdala. In the present study, male Wistar rats received fluoxetine or vehicle after exposure to a single prolonged stress (SPS), an animal model of PTSD. In vivo proton magnetic resonance spectroscopy ((1)H-MRS) was performed -1, 1, 4, 7 and 14 days after SPS to examine the effects of fluoxetine on neurometabolite changes in amygdala, hippocampus and thalamus. SPS increased the N-acetylaspartate (NAA)/creatine (Cr) and choline moieties (Cho)/Cr ratios in the bilateral amygdala on day 4, decreased the NAA/Cr ratio in the left hippocampus on day 1, and increased both ratios in the right hippocampus on day 14. But no significant change was found in the thalamus. Fluoxetine treatment corrected the SPS increases in the NAA/Cr and Cho/Cr levels in the amygdala on day 4 and in the hippocampus on day 14, but it failed to normalise SPS-associated decreases in NAA/Cr levels in the left hippocampus on day 1. These results suggested that metabolic abnormalities in the amygdala and the hippocampus were involved in SPS, and different effects of fluoxetine in correcting SPS-induced neurometabolite changes among the three areas. These findings have implications for fluoxetine treatment in PTSD. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Radionuclide concentration ratios in Australian terrestrial wildlife and livestock: data compilation and analysis.

PubMed

Johansen, M P; Twining, J R

2010-11-01

Radionuclide concentrations in Australian terrestrial fauna, including indigenous kangaroos and lizards, as well as introduced sheep and water buffalo, are of interest when considering doses to human receptors and doses to the biota itself. Here, concentration ratio (CR) values for a variety of endemic and introduced Australian animals with a focus on wildlife and livestock inhabiting open rangeland are derived and reported. The CR values are based on U- and Th-series concentration data obtained from previous studies at mining sites and (241)Am and (239/240)Pu data from a former weapons testing site. Soil-to-muscle CR values of key natural-series radionuclides for grazing Australian kangaroo and sheep are one to two orders of magnitude higher than those of grazing cattle in North and South America, and for (210)Po, (230)Th, and (238)U are one to two orders of magnitude higher than the ERICA tool reference values. When comparing paired kangaroo and sheep CR values, results are linearly correlated (r = 0.81) for all tissue types. However, kidney and liver CR values for kangaroo are typically higher than those of sheep, particularly for (210)Pb, and (210)Po, with values in kangaroo liver more than an order of magnitude higher than those in sheep liver. Concentration ratios for organs are typically higher than those for muscle including those for (241)Am and (239/240)Pu in cooked kangaroo and rabbit samples. This study provides CR values for Australian terrestrial wildlife and livestock and suggests higher accumulation rates for select radionuclides in semi-arid Australian conditions compared with those associated with temperate conditions.

Contrast ratio and masking ability of three ceramic veneering materials.

PubMed

Shono, N N; Al Nahedh, H N A

2012-01-01

Porcelain veneer materials are translucent and are therefore affected by their thickness as well as the color of the underlying substructure, which limits their masking ability and compromises the esthetic result in heavily stained teeth. The purpose of this study was to compare the contrast ratio (CR) and masking ability of three different veneering ceramics with two thicknesses by measuring the color differences over white and black backgrounds. Correlations between CR and masking ability of these veneering ceramics were evaluated. A total of 30 disc-shaped specimens (12 mm diameter × 1.0 mm or 1.5 mm) were fabricated in shade A2 from three types of all-ceramic systems: IPS e.max Press (IPSe; Ivoclar Vivadent, Schaan, Liechtensein), Vita VM7 (VM7; VITA Zahnfabrik, Bad Säckingen, Germany), and Nobel Rondo Press Alumina: Solo (NRPA; Nobel Biocare, Zürich-Flughafen, Switzerland). The CR, defined as the ratio of illuminance (Y) of the test material when placed on the black background (Yb) to the illuminance of the same material when placed over a white background (Yw), was determined (CR=Yb/Yw). The color (CIE L*a*b*) and Y of each specimen were measured over standard white and black tiles using a spectrophotometer (ColorEye 7000 A, Model C6, GretagMacbeth, New Windsor, NY, USA). Masking abilities of the specimens were determined by measuring the color difference (ΔE) over white and black backgrounds. Both CR and ΔE data were analyzed using two-way analysis of variance (ANOVA). One-way ANOVA was used to compare the mean values of CR across the three materials followed by the Duncan multiple comparison test. The correlations between CR and ΔE were determined by comparing R(2) values obtained from a linear regression analysis. A Student t-test for independent samples was used to compare the mean contrast ratio and ΔE values for the two thicknesses. CR values of NRPA were significantly less than those of IPSe and VM7, and the CR of IPSe was higher than that of VM7. Furthermore, CR increased as the thickness of the discs increased to 1.5 mm for all three materials. Mean ΔE values were significantly higher with 1.0-mm-thick discs than with 1.5-mm discs. Among the three materials it was observed that NRPA had the highest ΔE when compared with IPSe or VM7, whereas the ΔE of the latter two were not significantly different from one another. There was a strong linear correlation between CR and masking ability. CR and masking ability are affected by the type as well as the thickness of the ceramic used. IPSe and VM7 are similar in their masking abilities, whereas NRPA had the lowest masking ability. NRPA was the most translucent, followed by VM7; IPSe was the most opaque. None of the materials tested was able to completely mask the black background. It is therefore recommended that the type of ceramic should be chosen according to each clinical situation.

Multi-scale analysis of the effect of nano-filler particle diameter on the physical properties of CAD/CAM composite resin blocks.

PubMed

Yamaguchi, Satoshi; Inoue, Sayuri; Sakai, Takahiko; Abe, Tomohiro; Kitagawa, Haruaki; Imazato, Satoshi

2017-05-01

The objective of this study was to assess the effect of silica nano-filler particle diameters in a computer-aided design/manufacturing (CAD/CAM) composite resin (CR) block on physical properties at the multi-scale in silico. CAD/CAM CR blocks were modeled, consisting of silica nano-filler particles (20, 40, 60, 80, and 100 nm) and matrix (Bis-GMA/TEGDMA), with filler volume contents of 55.161%. Calculation of Young's moduli and Poisson's ratios for the block at macro-scale were analyzed by homogenization. Macro-scale CAD/CAM CR blocks (3 × 3 × 3 mm) were modeled and compressive strengths were defined when the fracture loads exceeded 6075 N. MPS values of the nano-scale models were compared by localization analysis. As the filler size decreased, Young's moduli and compressive strength increased, while Poisson's ratios and MPS decreased. All parameters were significantly correlated with the diameters of the filler particles (Pearson's correlation test, r = -0.949, 0.943, -0.951, 0.976, p < 0.05). The in silico multi-scale model established in this study demonstrates that the Young's moduli, Poisson's ratios, and compressive strengths of CAD/CAM CR blocks can be enhanced by loading silica nanofiller particles of smaller diameter. CAD/CAM CR blocks by using smaller silica nano-filler particles have a potential to increase fracture resistance.

Inhibition of Thymic Adipogenesis by Caloric Restriction Is Coupled with Reduction in Age-Related Thymic Involution1

PubMed Central

Yang, Hyunwon; Youm, Yun-Hee; Dixit, Vishwa Deep

2009-01-01

Aging of thymus is characterized by reduction in naive T cell output together with progressive replacement of lymphostromal thymic zones with adipocytes. Determining how calorie restriction (CR), a prolongevity metabolic intervention, regulates thymic aging may allow identification of relevant mechanisms to prevent immunosenescence. Using a mouse model of chronic CR, we found that a reduction in age-related thymic adipogenic mechanism is coupled with maintenance of thymic function. The CR increased cellular density in the thymic cortex and medulla and preserved the epithelial signatures. Interestingly, CR prevented the age-related increase in epithelial-mesenchymal transition (EMT) regulators, FoxC2, and fibroblast-specific protein-1 (FSP-1), together with reduction in lipid-laden thymic fibroblasts. Additionally, CR specifically blocked the age-related elevation of thymic proadipogenic master regulator, peroxisome proliferator activated receptor γ (PPARγ), and its upstream activator xanthine-oxidoreductase (XOR). Furthermore, we found that specific inhibition of PPARγ in thymic stromal cells prevented their adipogenic transformation in an XOR-dependent mechanism. Activation of PPARγ-driven adipogenesis in OP9-DL1 stromal cells compromised their ability to support T cell development. Conversely, CR-induced reduction in EMT and thymic adipogenesis were coupled with elevated thymic output. Compared with 26-mo-old ad libitum fed mice, the T cells derived from age-matched CR animals displayed greater proliferation and higher IL-2 expression. Furthermore, CR prevented the deterioration of the peripheral TCR repertoire diversity in older animals. Collectively, our findings demonstrate that reducing proadipogenic signaling in thymus via CR may promote thymopoiesis during aging. PMID:19648267

1H-MRS in autism spectrum disorders: a systematic meta-analysis.

PubMed

Ipser, Jonathan C; Syal, Supriya; Bentley, Judy; Adnams, Colleen M; Steyn, Bennie; Stein, Dan J

2012-09-01

We conducted a systematic review and meta-analysis of proton magnetic resonance spectroscopy (1H-MRS) studies comparing autism spectrum disorder (ASD) patients with healthy controls, with the aim of profiling ASD-associated changes in the metabolites N-acetyl-aspartate (NAA) and Creatine (Cr). Meta-regression models of NAA and Cr levels were employed, using data from 20 eligible studies (N = 852), to investigate age-dependent differences in both global brain and region-specific metabolite levels, while controlling for measurement method (Cr-ratio versus absolute concentrations). Decreased NAA concentrations that were specific to children were found for whole-brain grey and white matter. In addition, a significant decrease in NAA was evident across age categories in the parietal cortex, the cerebellum, and the anterior cingulate cortex. Higher levels of Cr were observed for ASD adults than children in global grey matter, with specific increases for adults in the temporal lobe and decreased Cr in the occipital lobe in children. No differences were found for either NAA or Cr in the frontal lobes. These data provide some evidence that ASD is characterized by age-dependent fluctuations in metabolite levels across the whole brain and at the level of specific regions thought to underlie ASD-associated behavioural and affective deficits. Differences in Cr as a function of age and brain region suggests caution in the interpretation of Cr-based ratio measures of metabolites. Despite efforts to control for sources of heterogeneity, considerable variability in metabolite levels was observed in frontal and temporal regions, warranting further investigation.

Valence of Ti, V, and Cr in Apollo 14 aluminous basalts 14053 and 14072

NASA Astrophysics Data System (ADS)

Simon, Steven B.; Sutton, Stephen R.

2017-09-01

The valences of Ti, V, and Cr in olivine and pyroxene, important indicators of the fO2 of the source region of their host rocks, can be readily measured nondestructively by XANES (X-ray absorption near edge structure) spectroscopy, but little such work has been done on lunar rocks, and there is some uncertainty regarding the presence of Ti3+ in lunar silicates and the redox state of the lunar mantle. This is the first study involving direct XANES measurement of valences of multivalent cations in lunar rocks. Because high alumina activity facilitates substitution of Ti cations into octahedral rather than tetrahedral sites in pyroxene and Ti3+ only enters octahedral sites, two aluminous basalts from Apollo 14, 14053 and 14072, were studied. Most pyroxene contains little or no detectable Ti3+, but in both samples relatively early, magnesian pyroxene was found that has Ti valences that are not within error of 4; in 14053, this component has an average Ti valence of 3.81 ± 0.06 (i.e., Ti3+/[Ti3+ + Ti4+ = 0.19]). This pyroxene has relatively low atomic Ti/Al ratios (<0.4) due to crystallization before plagioclase, contrary to the long-held belief that lunar pyroxene with Ti/Al > 0.5 contains Ti3+ and pyroxene with lower ratios does not. Later pyroxene, with lower Mg/Fe and higher Ti/Al ratios, has higher proportions of Ti (all Ti4+) in tetrahedral sites. All pyroxene analyzed contains divalent Cr, ranging from 15 to 30% of the Cr present, and all but one analysis spot contains divalent V, accounting for 0 to 40% (typically 20-30%) of the V present. Three analyses of olivine in 14053 do not show any Ti3+, but Ti valences in 14072 olivine range from 4 down to 3.70 ± 0.10. In 14053 olivine, 50% of the Cr and 60% of the V are divalent. In 14072 olivine, the divalent percentages are 20% for Cr and 20-60% for V. These results indicate significant proportions of divalent Cr and V and limited amounts of trivalent Ti in the parental melts, especially when crystal/liquid partitioning preferences are taken into account. These features are consistent with an fO2 closer to IW - 2 than to IW - 1. Apollo 15 basalt 15555, analyzed for comparison with A-14 materials, has olivine with strongly reduced Cr (Cr2+/(Cr2+ + Cr3+) 0.9). Basalts from different sites may record redox differences between source regions.

Final Scientific/Technical Report--In-Situ Generation of Iron-Chromium Precipitates for Long Term Immobilization of Chromium at the Hanford Site

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

Butler, Elizabeth C.; Krumholz, Lee R.; Madden, Andrew S.

Hexavalent chromium (Cr(VI)) is a toxic ground water contaminant widespread at the Hanford site and many other industrial facilities. A common remediation method for Cr(VI) is in situ reduction/immobilization, in which soluble Cr(VI) is reduced to the less soluble trivalent Cr (Cr(III)). If iron (Fe) minerals are present during the process, Cr(III) precipitates as a mixed Fe(III)-Cr(III) (Fe-Cr) solid. The objective of this exploratory research was to obtain preliminary evidence about the relationships among the method of Cr(VI) reduction (i.e., abiotic or microbial), the properties of the resulting Fe-Cr precipitates, and their tendencies to release soluble Cr(VI) in the presencemore » of the common manganese oxide birnessite. The results of this exploratory research project show that the conditions of Cr(VI) reduction—specifically the ratio of Cr to Fe, and/or whether the Cr(VI) reductant is a mineral or a microorganism—can significantly affect the tendency of the resulting Fe-Cr precipitate to release Cr(VI) to the environment in the presence of birnessite. These results suggest the chosen remediation conditions have the potential to strongly influence not only the initial success of in situ Cr(VI) reduction/immobilization, but also the potential for successful long term sequestration of Cr in the form of stable soil precipitates.« less

High creatinine clearance in critically ill patients with community-acquired acute infectious meningitis.

PubMed

Lautrette, Alexandre; Phan, Thuy-Nga; Ouchchane, Lemlih; Aithssain, Ali; Tixier, Vincent; Heng, Anne-Elisabeth; Souweine, Bertrand

2012-09-27

A high dose of anti-infective agents is recommended when treating infectious meningitis. High creatinine clearance (CrCl) may affect the pharmacokinetic / pharmacodynamic relationships of anti-infective drugs eliminated by the kidneys. We recorded the incidence of high CrCl in intensive care unit (ICU) patients admitted with meningitis and assessed the diagnostic accuracy of two common methods used to identify high CrCl. Observational study performed in consecutive patients admitted with community-acquired acute infectious meningitis (defined by >7 white blood cells/mm3 in cerebral spinal fluid) between January 2006 and December 2009 to one medical ICU. During the first 7 days following ICU admission, CrCl was measured from 24-hr urine samples (24-hr-UV/P creatinine) and estimated according to Cockcroft-Gault formula and the simplified Modification of Diet in Renal Disease (MDRD) equation. High CrCl was defined as CrCl >140 ml/min/1.73 m2 by 24-hr-UV/P creatinine. Diagnostic accuracy was performed with ROC curves analysis. Thirty two patients were included. High CrCl was present in 8 patients (25%) on ICU admission and in 15 patients (47%) during the first 7 ICU days for a median duration of 3 (1-4) days. For the Cockcroft-Gault formula, the best threshold to predict high CrCl was 101 ml/min/1.73 m2 (sensitivity: 0.96, specificity: 0.75, AUC = 0.90 ± 0.03) with a negative likelihood ratio of 0.06. For the simplified MDRD equation, the best threshold to predict high CrCl was 108 ml/min/1.73 m2 (sensitivity: 0.91, specificity: 0.80, AUC = 0.88 ± 0.03) with a negative likelihood ratio of 0.11. There was no difference between the estimated methods in the diagnostic accuracy of identifying high CrCl (p = 0.30). High CrCl is frequently observed in ICU patients admitted with community-acquired acute infectious meningitis. The estimated methods of CrCl could be used as a screening tool to identify high CrCl.

Study on film resistivity of Energy Conversion Components for MEMS Initiating Explosive Device

NASA Astrophysics Data System (ADS)

Ren, Wei; Zhang, Bin; Zhao, Yulong; Chu, Enyi; Yin, Ming; Li, Hui; Wang, Kexuan

2018-03-01

Resistivity of Plane-film Energy Conversion Components is a key parameter to influence its resistance and explosive performance, and also it has important relations with the preparation of thin film technology, scale, structure and etc. In order to improve the design of Energy Conversion Components for MEMS Initiating Explosive Device, and reduce the design deviation of Energy Conversion Components in microscale, guarantee the design resistance and ignition performance of MEMS Initiating Explosive Device, this paper theoretically analyzed the influence factors of film resistivity in microscale, through the preparation of Al film and Ni-Cr film at different thickness with micro/nano, then obtain the film resistivity parameter of the typical metal under different thickness, and reveals the effect rule of the scale to the resistivity in microscale, at the same time we obtain the corresponding inflection point data.

Fabrication and properties of Nd(Tb,Dy)Co/Cr films with perpendicular magnetic anisotropy

NASA Astrophysics Data System (ADS)

Cheng, Weiming; Miao, Xiangshui; Yan, Junbing; Cheng, Xiaomin

2009-08-01

Light rare earth-heavy rare earth-transition metal films (LRE-HRE-TM)have large saturation magnetization (Ms) and are the promising media for hybrid recording. In this paper, Nd(Tb,Dy)Co/Cr films with perpendicular magnetic anisotropy were successfully fabricated onto glass substrate by RF magnetron sputtering and the effects of sputtering technology parameters and Nd substitution for HRE atoms on the magnetic properties were investigated. It was found that when the sputtering power and sputtering time are 250W and 4min, respectively, the magnetic properties of Nd(Tb,Dy)Co/Cr films obtain optimization, perpendicular coercivity, Ms and remanence square ratio(S) of NdTbCo/Cr film reach 3.8kOe, 247emu/cm3 and 0.801, respectively. With the increasing of Nd concentration, Ms increases, while the coercivity (Hc)and the temperature stability of magnetic properties decrease distinctly. These results can be explained by the ferri-magnetic structure of the RE-TM alloy.

Pair luminescence in Cr3+ -doped Ba2Mg(BO3)2

NASA Astrophysics Data System (ADS)

Bondzior, Bartosz; Miniajluk, Natalia; Dereń, Przemysław J.

2018-05-01

Cr3+ ions were introduced to the Ba2Mg(BO3)2 host to provide information about the site occupation, crystal field strength, and the site symmetry. The samples were synthesized by solid-state reaction. Emission observed under 440 nm excitation was characteristic for Cr3+ ions in strong octahedral ligand field with Dq/B parameter ratio 2.74 and sharp R line at 698 nm. The charge mismatch between Cr3+ dopant and Mg2+ host ion is compensated by the creation of Cr3+ pair in the vicinity of Ba or Mg vacancy. The emission decay curve is bi-exponential with decay times 1.2 and 13.3 ms.

Magnetic interaction reversal in watermelon nanostructured Cr-doped Fe nanoclusters

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

Kaur, Maninder; Dai, Qilin; Bowden, Mark

2013-01-01

Cr-doped core-shell Fe/Fe-oxide nanoclusters (NCs) were synthesized at varied atomic percentages of Cr from 0 at. % to 8 at. %. The low concentrations of Cr (<10 at. %) were selected in order to inhibit the complete conversion of the Fe-oxide shell to Cr2O3 and the Fe core to FeCr alloy. The magnetic interaction in Fe/Fe-oxide NCs (rv25 nm) can be controlled by antiferromagnetic Cr-dopant. We report the origin of r-FeCr phase at very low Cr concentration (2 at. %) unlike in previous studies, and the interaction reversal from dipolar to exchange interaction in watermelon-like Cr-doped core-shell NCs. The giantmore » magnetoresistance (GMR) effect,1,2 where an antiferromagnetic (AFM) exchange coupling exists between two ferromagnetic (FM) layers separated by a certain type of magnetic or non-magnetic spacer,3 has significant potential for application in the magnetic recording industry. Soon after the discovery of the GMR, the magnetic properties of multilayer systems (FeCr) became a subject of intensive study. The application of bulk iron-chromium (Fe-Cr) alloys has been of great interest, as these alloys exhibit favorable prop- erties including corrosion resistance, high strength, hardness, low oxidation rate, and strength retention at elevated temper- ature. However, the structural and magnetic properties of Cr-doped Fe nanoclusters (NCs) have not been investigated in-depth. Of all NCs, Fe-based clusters have unique magnetic properties as well as favorable catalytic characteristics in reactivity, selectivity, and durability.4 The incorporation of dopant of varied type and concentration in Fe can modify its chemical ordering, thereby optimizing its electrical, optical, and magnetic properties and opening up many new applications. The substitution of an Fe atom (1.24 A°) by a Cr atom (1.25 A° ) can easily modify the magnetic properties, since (i) the curie temperature (Tc ) of Fe is 1043 K, while Cr is an itinerant AFM with a bulk Neel temperature TN =311 K, and (ii) Fe and Cr share the same crystal structure (bcc) with only 0.5% difference between their lattice constants.« less

Elevated cerebral glutamate and myo-inositol levels in cognitively normal middle-aged adults with metabolic syndrome.

PubMed

Haley, Andreana P; Gonzales, Mitzi M; Tarumi, Takashi; Miles, Steven C; Goudarzi, Katayoon; Tanaka, Hirofumi

2010-12-01

Metabolic syndrome (MetS) is a cluster of risk factors associated with significant cardiovascular morbidity and mortality and diminished cognitive function. Given that the cerebral mechanisms mediating the relationship between peripheral metabolic dysfunction and cognitive impairment are unknown, we set out to examine the relationship between diagnosis of metabolic syndrome and cerebral metabolism. Thirteen participants with MetS (aged 48 ± 6 years) and 25 healthy adults (aged 51 ± 6 years) underwent neuropsychological assessment, health screen and proton magnetic resonance spectroscopy ((1)H MRS) examining N-acetyl-aspartate (NAA), myo-inositol (mI), creatine (Cr), choline (Cho), and glutamate (Glu) concentrations in occipitoparietal grey matter. Cerebral metabolite ratios (NAA/Cr, Cho/Cr, mI/Cr, and Glu/Cr) of participants with MetS, defined by the International Diabetes Federation criteria, were compared with controls matched for age, education, cognition, and emotional function. There were no significant differences in global cognitive function, memory, language, and psychomotor performance between the groups. Diagnosis of MetS was associated with significantly higher mI/Cr (F(1,36) = 5.02, p = 0.031) and Glu/Cr ratio (F(1,36) = 4.81, p = 0.035). Even in cognitively normal adults, MetS is related to cerebral metabolic disturbances, a possible indication of early brain vulnerability. Longitudinal studies that begin in mid-life can help validate the use of (1)H MRS markers as indicators of long-term cognitive outcomes.

Itinerant G-type antiferromagnetic order in SrCr 2 As 2

DOE PAGES

Das, Pinaki; Sangeetha, N. S.; Lindemann, George R.; ...

2017-07-07

Here, neutron-diffraction and magnetic susceptibility studies of polycrystalline SrCr 2As 2 reveal that this compound is an itinerant G-type antiferromagnet below the Néel temperature T N = 590(5) K with the Cr magnetic moments aligned along the tetragonal c axis. The system remains tetragonal to the lowest measured temperature (~12 K). The lattice parameter ratio c/a and the magnetic moment saturate at about the same temperature below ~200 K, indicating a possible magnetoelastic coupling. The ordered moment μ = 1.9(1)μ B/Cr, measured at T = 12 K, is significantly reduced compared to its localized value (4μ B/Cr) due to themore » itinerant character brought about by hybridization between the Cr 3d and As 4p orbitals.« less

Itinerant G-type antiferromagnetic order in SrCr2As2

NASA Astrophysics Data System (ADS)

Das, Pinaki; Sangeetha, N. S.; Lindemann, George R.; Heitmann, T. W.; Kreyssig, A.; Goldman, A. I.; McQueeney, R. J.; Johnston, D. C.; Vaknin, D.

2017-07-01

Neutron-diffraction and magnetic susceptibility studies of polycrystalline SrCr2As2 reveal that this compound is an itinerant G-type antiferromagnet below the Néel temperature TN = 590(5) K with the Cr magnetic moments aligned along the tetragonal c axis. The system remains tetragonal to the lowest measured temperature (˜12 K). The lattice parameter ratio c /a and the magnetic moment saturate at about the same temperature below ˜200 K, indicating a possible magnetoelastic coupling. The ordered moment μ =1.9 (1 ) μB /Cr , measured at T =12 K, is significantly reduced compared to its localized value (4 μB /Cr ) due to the itinerant character brought about by hybridization between the Cr 3 d and As 4 p orbitals.

Itinerant G-type antiferromagnetic order in SrCr 2 As 2

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

Das, Pinaki; Sangeetha, N. S.; Lindemann, George R.

Here, neutron-diffraction and magnetic susceptibility studies of polycrystalline SrCr 2As 2 reveal that this compound is an itinerant G-type antiferromagnet below the Néel temperature T N = 590(5) K with the Cr magnetic moments aligned along the tetragonal c axis. The system remains tetragonal to the lowest measured temperature (~12 K). The lattice parameter ratio c/a and the magnetic moment saturate at about the same temperature below ~200 K, indicating a possible magnetoelastic coupling. The ordered moment μ = 1.9(1)μ B/Cr, measured at T = 12 K, is significantly reduced compared to its localized value (4μ B/Cr) due to themore » itinerant character brought about by hybridization between the Cr 3d and As 4p orbitals.« less

ZnCr2S4: Highly effective photocatalyst converting nitrate into N2 without over-reduction under both UV and pure visible light

NASA Astrophysics Data System (ADS)

Yue, Mufei; Wang, Rong; Cheng, Nana; Cong, Rihong; Gao, Wenliang; Yang, Tao

2016-08-01

We propose several superiorities of applying some particular metal sulfides to the photocatalytic nitrate reduction in aqueous solution, including the high density of photogenerated excitons, high N2 selectivity (without over-reduction to ammonia). Indeed, ZnCr2S4 behaved as a highly efficient photocatalyst, and with the assistance of 1 wt% cocatalysts (RuOx, Ag, Au, Pd, or Pt), the efficiency was greatly improved. The simultaneous loading of Pt and Pd led to a synergistic effect. It offered the highest nitrate conversion rate of ~45 mg N/h together with the N2 selectivity of ~89%. Such a high activity remained steady after 5 cycles. The optimal apparent quantum yield at 380 nm was 15.46%. More importantly, with the assistance of the surface plasma resonance effect of Au, the visible light activity achieved 1.352 mg N/h under full arc Xe-lamp, and 0.452 mg N/h under pure visible light (λ > 400 nm). Comparing to the previous achievements in photocatalytic nitrate removal, our work on ZnCr2S4 eliminates the over-reduction problem, and possesses an extremely high and steady activity under UV-light, as well as a decent conversion rate under pure visible light.

ZnCr2S4: Highly effective photocatalyst converting nitrate into N2 without over-reduction under both UV and pure visible light.

PubMed

Yue, Mufei; Wang, Rong; Cheng, Nana; Cong, Rihong; Gao, Wenliang; Yang, Tao

2016-08-03

We propose several superiorities of applying some particular metal sulfides to the photocatalytic nitrate reduction in aqueous solution, including the high density of photogenerated excitons, high N2 selectivity (without over-reduction to ammonia). Indeed, ZnCr2S4 behaved as a highly efficient photocatalyst, and with the assistance of 1 wt% cocatalysts (RuOx, Ag, Au, Pd, or Pt), the efficiency was greatly improved. The simultaneous loading of Pt and Pd led to a synergistic effect. It offered the highest nitrate conversion rate of ~45 mg N/h together with the N2 selectivity of ~89%. Such a high activity remained steady after 5 cycles. The optimal apparent quantum yield at 380 nm was 15.46%. More importantly, with the assistance of the surface plasma resonance effect of Au, the visible light activity achieved 1.352 mg N/h under full arc Xe-lamp, and 0.452 mg N/h under pure visible light (λ > 400 nm). Comparing to the previous achievements in photocatalytic nitrate removal, our work on ZnCr2S4 eliminates the over-reduction problem, and possesses an extremely high and steady activity under UV-light, as well as a decent conversion rate under pure visible light.

Synthesis and Characterization of Chromate Conversion Coatings on GALVALUME and Galvanized Steel Substrates

NASA Astrophysics Data System (ADS)

Domínguez-Crespo, M. A.; Onofre-Bustamante, E.; Torres-Huerta, A. M.; Rodríguez-Gómez, F. J.; Rodil, S. E.; Flores-Vela, A.

2009-07-01

The morphology, composition, and corrosion performance of chromate conversion coatings (CCCs) formed on GALVALUME (Fe-Al-Zn) and galvanized steel (Fe-Zn) samples have been studied, and different immersion times (0, 10, 30, and 60 seconds) have been compared. The coated surfaces were analyzed using light microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical measurements in a NaCl solution (3 wt pct). The electrochemical measurements were carried out using the polarization resistance, Tafel, and ac impedance methods. A nonuniform growth of the CCCs having a porous morphology and cracks that appear extended to the base metal was observed. The XRD patterns show that the coatings mainly consist of CrO3, Cr2O3, and traces of Cr2O{7/-2}. The electrochemical results show that GALVALUME presents a better behavior than that of the galvanized steel alloys at each dipping time. The SEM micrographs show that the galvanized steel treatments resulted in the formation of a more uniform film, but their protection barrier broke down faster than that of the GALVALUME samples in contact with the aggressive media. The samples that underwent the lowest degree of dissolution were those with a dipping time of 30 seconds. The difference in the corrosion protection given by the two substrate types could be attributed to the structural properties, grain size, composition, and roughness, which affect oxygen diffusion.

Simultaneous Formation of Artificial SEI Film and 3D Host for Stable Metallic Sodium Anodes.

PubMed

Zhang, Di; Li, Bin; Wang, Shuai; Yang, Shubin

2017-11-22

Metallic sodium is a promising anode for sodium-based batteries, owing to its high theoretical capacity (1165 mAh g -1 ) and low potential (-2.714 V vs standard hydrogen electrode). However, the growth of sodium dendrites and the infinite volume change of metallic sodium during sodium striping/plating result in a low Coulombic efficiency and poor cycling stability, generating a safety hazard of sodium-based batteries. Here, an efficient approach was proposed to simultaneously generate an artificial SEI film and 3D host for metallic sodium based on a conversion reaction (CR) between sodium and MoS 2 (4Na + MoS 2 = 2Na 2 S + Mo) at room temperature. In the resultant sodium-MoS 2 hybrid after the conversion reaction (Na-MoS 2 (CR)), the production Na 2 S is homogeneously dispersed on the surface of metallic sodium, which can act as an artificial SEI film, efficiently preventing the growth of sodium dendrites; the residual MoS 2 nanosheets can construct a 3D host to confine metallic sodium, accommodating largely the volume change of sodium. Consequently, the Na-MoS 2 (CR) hybrid exhibits very low overpotential of 25 mV and a very long cycle stability more than 1000 cycles. This novel strategy is promising to promote the development of metal (lithium, sodium, zinc)-based electrodes.

Application of zeolitic material synthesized from thermally treated sediment to the removal of trivalent chromium from wastewater.

PubMed

Guan, Qingyu; Wu, Deyi; Lin, Yan; Chen, Xuechu; Wang, Xinze; Li, Chunjie; He, Shengbing; Kong, Hainan

2009-08-15

Zeolitic materials were synthesized from thermally treated sediment by alkali treatment using different NaOH/sediment ratios. Characterization of the materials was done by XRD, FTIR, cation exchange capacity and specific surface area. Use of high NaOH/sediment ratio favored the formation of zeolite. The potential value of the zeolitic materials for the retention of trivalent chromium from water was examined. The maximum of Cr(III) sorption by the zeolitic materials, determined by a repeated batch equilibration method, ranged from 38.9 to 75.8 mg/g which was much greater than that of the thermally treated sediment (6.3 mg/g). No release of sorbed Cr(III) by 1.0M MgCl(2) at pH 7 was observed but Cr(III) desorption by ionic electrolyte increased with decreasing pH. The zeolitic materials could completely remove Cr(III) from wastewater even in the presence of Na(+) and Ca(2+) with high concentrations with a dose above 2.5 g/L. The pH-dependent desorption behavior and the high selectivity of zeolitic material for Cr(III) were explained by sorption at surface hydroxyl sites and formation of surface precipitates.

Electrostatic control of phospholipid polymorphism.

PubMed

Tarahovsky, Y S; Arsenault, A L; MacDonald, R C; McIntosh, T J; Epand, R M

2000-12-01

A regular progression of polymorphic phase behavior was observed for mixtures of the anionic phospholipid, cardiolipin, and the cationic phospholipid derivative, 1, 2-dioleoyl-sn-glycero-3-ethylphosphocholine. As revealed by freeze-fracture electron microscopy and small-angle x-ray diffraction, whereas the two lipids separately assume only lamellar phases, their mixtures exhibit a symmetrical (depending on charge ratio and not polarity) sequence of nonlamellar phases. The inverted hexagonal phase, H(II,) formed from equimolar mixtures of the two lipids, i.e., at net charge neutrality (charge ratio (CR((+/-))) = 1:1). When one type of lipid was in significant excess (CR((+/-)) = 2:1 or CR((+/-)) = 1:2), a bicontinuous cubic structure was observed. These cubic phases were very similar to those sometimes present in cellular organelles that contain cardiolipin. Increasing the excess of cationic or anionic charge to CR((+/-)) = 4:1 or CR((+/-)) = 1:4 led to the appearance of membrane bilayers with numerous interlamellar contacts, i.e., sponge structures. It is evident that interactions between cationic and anionic moieties can influence the packing of polar heads and hence control polymorphic phase transitions. The facile isothermal, polymorphic interconversion of these lipids may have important biological and technical implications.

Synthesis and characterization of Cr-MSU-1 and its catalytic application for oxidation of styrene

NASA Astrophysics Data System (ADS)

Liu, Hong; Wang, Zhigang; Hu, Hongjiu; Liang, Yuguang; Wang, Mengyang

2009-07-01

Chromium-containing mesoporous silica material Cr-MSU-1 was synthesized using lauryl alcohol-polyoxyethylene (23) ether as templating agent under the neutral pH condition by two-step method. The sample was characterized by XRD, TEM, FT-IR, UV-Vis, ESR, ICP-AES and N 2 adsorption. Its catalytic performance for oxidation of styrene was studied. Effects of the solvent used, the styrene/H 2O 2 mole ratio and the reaction temperature and time on the oxidation of styrene over the Cr-MSU-1 catalyst were examined. The results indicate that Cr ions have been successfully incorporated into the framework of MSU-1 and the Cr-MSU-1 material has a uniform worm-like holes mesoporous structure. After Cr-MSU-1 is calcined, most of Cr 3+ is oxidized to Cr 5+ and Cr 6+ in tetrahedral coordination and no extra-framework Cr 2O 3 is formed. The Cr-MSU-1 catalyst is highly active for the selective oxidation of styrene and the main reaction products over Cr-MSU-1 are benzaldehyde and phenylacetaldehyde. Its catalytic performance remains stable within five repeated runs and no leaching is noticed for this chromium-based catalyst.

Anion-exchange high-performance liquid chromatography of water-soluble chromium (VI) and chromium (III) complexes in biological materials.

PubMed

Suzuki, Y

1987-04-10

A high-performance anion-exchange liquid chromatograph coupled to visible-range (370 nm) and UV (280 nm) detectors and an atomic-absorption spectrometer allowed the rapid determination of CrVI and/or complexes of CrIII in rat plasma, erythrocyte lysate and liver supernatant treated with CrVI or CrIII in vitro. CrVI in the eluates was determined using both the visible-range detector and atomic-absorption spectrometer (AAS). The detection limits of CrVI in standard solutions using these methods were 2 and 5 ng (signal-to-noise ratio = 2), respectively. Separations of the biological components and of CrIII complexes were monitored by UV and AAS analyses, respectively. Time-related decreases of CrVI accompanied by increases in CrIII complexes were observed, indicating the reduction of CrVI by some of the biological components. The reduction rates were considerably higher in the liver supernatant and erythrocyte lysate than in the plasma. These results indicate that the anion-exchange high-performance liquid chromatographic system is useful for simultaneous determination of CrVI and CrIII complexes in biological materials.

Origin discrimination of defatted pork via trace elements profiling, stable isotope ratios analysis, and multivariate statistical techniques.

PubMed

Park, Yu Min; Lee, Cheong Mi; Hong, Joon Ho; Jamila, Nargis; Khan, Naeem; Jung, Jong-Hyun; Jung, Young-Chul; Kim, Kyong Su

2018-09-01

This study verified the origin of 346 defatted Korean and non-Korean pork samples via trace elements profiling, and C and N stable isotope ratios analysis. The analyzed elements were 6 Li, 7 Li, 10 B, 11 B, 51 V , 50 Cr, 52 Cr, 53 Cr, 55 Mn, 58 Ni, 60 Ni, 59 Co, 63 Cu, 65 Cu, 64 Zn, 66 Zn, 69 Ga, 71 Ga, 75 As, 82 Se, 84 Sr, 86 Sr, 87 Sr, 88 Sr, 85 Rb, 94 Mo, 95 Mo, 97 Mo, 107 Ag, 109 Ag, 110 Cd, 111 Cd, 113 Cd, 112 Cd, 114 Cd, 116 Cd, 133 Cs, 206 Pb, 207 Pb, and 208 Pb. Content (mg/kg) of 51 V (0.012), 50 Cr (0.882), 75 As (0.017), 85 Rb (57.7), and 87 Sr (46.3) were high in Korean pork samples whereas 6 Li, 7 Li, 59 Co, 55 Mn, 58 Ni, 84 Sr, 86 Sr, 88 Sr, 111 Cd, and 133 Cs were found higher in non-Korean samples. The results of discriminant analysis showed that the trace elements content and stable isotope ratios were significant for the discrimination of geographical origins with a perfect discrimination rate of 100%. Copyright © 2018 Elsevier Ltd. All rights reserved.

Proton magnetic resonance spectroscopy in obsessive-compulsive disorder: evidence for reduced neuronal integrity in the anterior cingulate.

PubMed

Tükel, Raşit; Aydın, Kubilay; Ertekin, Erhan; Özyıldırım, Seda Şahin; Taravari, Vedat

2014-12-30

Neuroimaging studies have suggested that dysfunction of the cortico-striatal-thalamo-cortical (CSTC) circuit is a key pathophysiologic feature of obsessive-compulsive disorder (OCD). Several studies using proton magnetic resonance spectroscopy ((1)H MRS) have found abnormal neural metabolite concentrations among OCD patients. The aim of this study was to investigate the metabolic integrity of the anterior cingulate, caudate and putamen in OCD. In the present study, 32 unmedicated patients with OCD, including 23 who were drug-naïve, were compared using MRS with 32 healthy controls. Metabolite levels of N-acetylaspartate (NAA), choline (Cho) and myo-inositol (mI) were measured in terms of their ratios to creatine (Cr). The ratio of NAA/Cr was significantly lower in OCD patients than in healthy controls in the anterior cingulate. There was a tendency for levels of NAA/Cr to be lower in the caudate and the putamen in patients with OCD compared with healthy controls. NAA/Cr ratios were negatively correlated with the total scores on the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) in the anterior cingulate in patients with OCD. Our results support the significance and biochemical involvement of the anterior cingulate cortex (ACC) in the pathophysiology of OCD. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Cerebral white matter blood flow and energy metabolism in multiple sclerosis.

PubMed

Steen, Christel; D'haeseleer, Miguel; Hoogduin, Johannes M; Fierens, Yves; Cambron, Melissa; Mostert, Jop P; Heersema, Dorothea J; Koch, Marcus W; De Keyser, Jacques

2013-09-01

Cerebral blood flow (CBF) is reduced in normal-appearing white matter (NAWM) of subjects with multiple sclerosis (MS), but the underlying mechanism is unknown. The objective of this article is to assess the relationship between reduced NAWM CBF and both axonal mitochondrial metabolism and astrocytic phosphocreatine (PCr) metabolism. Ten healthy controls and 25 MS subjects were studied with 3 Tesla magnetic resonance imaging. CBF was measured using pseudo-continuous arterial spin labeling. N-acetylaspartate/creatine (NAA/Cr) ratios (axonal mitochondrial metabolism) were obtained using (1)H-MR spectroscopy and PCr/β-ATP ratios using (31)P-MR spectroscopy. In centrum semiovale NAWM, we assessed correlations between CBF and both NAA/Cr and PCr/β-ATP ratios. Subjects with MS had a widespread reduction in CBF of NAWM (centrum semiovale, periventricular, frontal and occipital), and gray matter (frontoparietal cortex and thalamus). Compared to controls, NAA/Cr in NAWM of the centrum semiovale of MS subjects was decreased, whereas PCr/β-ATP was increased. We found no correlations between CBF and PCr/β-ATP. CBF and NAA/Cr correlated in controls (p = 0.02), but not in MS subjects (p = 0.68). Our results suggest that in MS patients there is no relationship between reduced CBF in NAWM and impaired axonal mitochondrial metabolism or astrocytic PCr metabolism.

Emi-Flective Display Device with Attribute of High Glare-Free-Ambient-Contrast-Ratio

NASA Astrophysics Data System (ADS)

Yang, Bo-Ru; Hsu, Chuan-Wei; Shieh, Han-Ping D.

2007-11-01

We have demonstrated the integration of an organic light emitting device (OLED) and a reflective liquid crystal display (R-LCD) which was termed an emi-flective display. The glare-free-ambient-contrast-ratio (GFA-CR) was used to evaluate the image quality of display devices under ambient light. Through integrating the OLED with R-LCD, the GFA-CR of the device achieved an improvement by a factor of 8 compared with that of the OLED alone. Moreover, the integrated R-LCD showed a GFA-CR of 100:1 within a viewing cone of 20° which can suppress the wash-out of OLED and is more power-saving in the sunlight. Therefore, an emi-flective display is a promising technique for mobile applications.

Evaluating Alternative Methodologies for Capturing As-Built Building Information Models (BIM) For Existing Facilities

DTIC Science & Technology

2010-08-01

Jeffery P. Holland was the Director. ERDC/CERL CR-10-1 iv Unit Conversion Factors Multiply By To Obtain British thermal units (International Table...360 Panoramic Optic™ is a specially designed lens attachment, with an exclusive optical reflector, which captures an entire 360 degree panorama

The Oxidation of Secondary Alcohols with Cr (VI).

ERIC Educational Resources Information Center

Mason, Timothy J.

1982-01-01

Describes experiments in which acid chromate oxidation rates of four secondary alcohols are determined and related to the differences in strain relief involved in the conversion of the alcohols to their respective ketone products. All four oxidations can be completed in a 4-hour laboratory period. (Author/JN)

Study on the properties of chromium residue-cement matrices (CRCM) and the influences of superplasticizers on chromium(VI)-immobilising capability of cement matrices.

PubMed

Shi, Hui-Sheng; Kan, Li-Li

2009-03-15

The study of cementitious activity of chromium residue (CR) was carried out to formulate the properties of chromium residue-cement matrices (CRCM) by blending CR with Ordinary Portland Cement (OPC). The particle size distribution, microstructures of CR were investigated by some apparatuses, and physical properties, leaching behavior of hexavalent chromium [Cr(VI)] of CRCM were also determined by some experiments. Three types of commonly used superplasticizers (sulphonated acetone formaldehyde superplasticizer (J1), polycarboxylate-based superplasticizer (J2) and naphthalene superplasticizer (J3)) were chosen to investigate their influences on the physical properties and the Cr(VI)-immobilisation in the leachate of the CRCM hardened pastes. The results show that the CR has a certain cementitious activity. The incorporation of CR improves the pore size distribution of CRCM. The Cr(VI) concentrations in the leachate of CRCM significantly decrease by incorporation of J2. Among three superplasticizers, J2 achieves lowest Cr(VI) leaching ratio. Based on this study, it is likely to develop CR as a potential new additive used in cement-based materials.

Hair chromium as an index of chromium exposure of tannery workers.

PubMed Central

Randall, J A; Gibson, R S

1989-01-01

The use of hair chromium (Cr) concentrations as an index of Cr exposure of tannery workers was investigated. As has been shown earlier, Cr from Cr III compounds used in the leather tanning industry is absorbed because concentrations of Cr in serum and urine of tannery workers are significantly increased compared with corresponding concentrations for unexposed controls. Hair samples were collected from 71 male tannery workers from four southern Ontario tanneries and from 53 male controls not exposed to Cr in the workplace. Subjects were matched for age, race, and socioeconomic status. Hair samples were washed, ashed in a low temperature asher, and analysed by flameless atomic absorption. The median hair Cr concentrations for the tannery workers (551 ng/g) was significantly higher (p = 0.0001) than for the controls (123 ng/g). For the tannery workers, hair Cr concentrations were positively and significantly correlated with serum Cr (r = 0.52, p less than 0.01) and with the preshift and postshift urinary Cr/creatinine ratios (r = 0.43, p less than 0.01; r = 0.64, p less than 0.01, respectively). These data indicate that trivalent Cr absorbed from leather tanning compounds results in raised concentrations of Cr in hair and that hair Cr concentrations may be used as an index of industrial Cr exposure. PMID:2930727

Study of Cr(VI) adsorption onto magnetite nanoparticles using synchrotron-based X-ray absorption spectroscopy

NASA Astrophysics Data System (ADS)

Chen, Yen-Hua; Liu, Dian-Yu; Lee, Jyh-Fu

2018-04-01

In this study, the efficiency of Cr(VI) adsorption onto nano-magnetite was examined by batch experiments, and the Cr(VI) adsorption mechanism was investigated using synchrotron-based X-ray absorption spectroscopy. Magnetite nanoparticles with a mean diameter of 10 nm were synthesized using an inexpensive and simple co-precipitation method. It shows a saturation magnetization of 54.3 emu/g, which can be recovered with an external magnetic field. The adsorption data fitted the Langmuir adsorption isotherm well, implying a monolayer adsorption behavior of Cr(VI) onto nano-magnetite. X-ray absorption spectroscopy results indicate that the adsorption mechanism involves electron transfer between Fe(II) in nano-magnetite (Fe2+OFe3+ 2O3) and Cr(VI) to transform into Cr(III), which may exist as an Fe(III)-Cr(III) mixed solid phase. Moreover, the Cr(III)/Cr(VI) ratio in the final products can be determined by the characteristic pre-edge peak area of Cr(VI) in the Cr K-edge spectrum. These findings suggest that nano-magnetite is effective for Cr(VI) removal from wastewater because it can transform highly poisonous Cr(VI) species into nontoxic Cr(III) compounds, which are highly insoluble and immobile under environmental conditions.

Density of CD8+ lymphocytes in biopsy samples combined with the circulating lymphocyte ratio predicts pathologic complete response to chemoradiotherapy for rectal cancer.

PubMed

Xiao, Binyi; Peng, Jianhong; Zhang, Rongxin; Xu, Jing; Wang, Yongchun; Fang, Yujing; Lin, Junzhong; Pan, Zhizhong; Wu, Xiaojun

2017-01-01

The systemic status and local immune status, as determined by the neutrophil-lymphocyte ratio (NLR) or the lymphocyte ratio (LYMR) and tumor-infiltrating lymphocyte (TIL) count, respectively, have been suggested as predictors of the tumor response to neoadjuvant chemoradiotherapy (nCRT) in rectal cancer, although the utility of these measures remains controversial. We aimed to investigate the values of the LYMR, NLR and TIL count and their combinations (TIL-LYMR/TIL-NLR) in predicting pathologic complete response (pCR) after nCRT. Pretreatment biopsy samples and data from the blood tests of 92 patients with rectal cancer who underwent curative resection after nCRT were retrospectively obtained. CD8+ TILs were immunostained using an antibody against CD8. The density of CD8+ TILs was recorded as the number of CD8+ T cells per square millimeter, and the results were classified as either "high" or "low". The LYMR and NLR were calculated using pretreatment blood test data and categorized into either "high" or "low" groups. TIL-LYMR was graded as "low," "mid" or "high" when neither, one or both the CD8+ TIL count and LYMR were "high," respectively. TIL-NLR was graded similarly. The associations between TILs and LYMR, NLR and their combinations (TIL-LYMR/TIL-NLR) were evaluated. pCR was significantly associated with a high LYMR, a low NLR and increased chemotherapy cycles ( P =0.039, P =0.043 and P =0.015, respectively), but not with the CD8+ TIL count or carcinoembryonic antigen (CEA) level ( P =0.100 and P =0.590, respectively). Additionally, 40% of patients with high LYMR and 40.7% with low NLR achieved pCR, whereas only 19.7% with low LYMR and 20.3% with high NLR did so. When the combinations were assessed, TIL-LYMR showed a positive correlation with pCR ( P =0.038), while no association between TIL-NLR and pCR was found ( P =0.916). In multivariate analysis, TIL-LYMR remained an independent predictor of pCR (odds ratio [OR]=1.833, 95% confidence interval [CI]=1.069-3.142, P =0.028). High LYMR, low NLR and high TIL-LYMR at baseline are predictive of pCR to nCRT for patients with rectal cancer. These parameters may help identify pCR patients and provide additional information for therapeutic decision-making.

A dynamic spectrum of monocytes arising from the in situ reprogramming of CCR2+ monocytes at a site of sterile injury

PubMed Central

Dal-Secco, Daniela; Wang, Jing; Zeng, Zhutian; Kolaczkowska, Elzbieta; Wong, Connie H.Y.; Petri, Björn; Ransohoff, Richard M.; Charo, Israel F.

2015-01-01

Monocytes are recruited from the blood to sites of inflammation, where they contribute to wound healing and tissue repair. There are at least two subsets of monocytes: classical or proinflammatory (CCR2hiCX3CR1low) and nonclassical, patrolling, or alternative (CCR2lowCX3CR1hi) monocytes. Using spinning-disk confocal intravital microscopy and mice with fluorescent reporters for each of these subsets, we were able to track the dynamic spectrum of monocytes that enter a site of sterile hepatic injury in vivo. We observed that the CCR2hiCX3CR1low monocytes were recruited early and persisted for at least 48 h, forming a ringlike structure around the injured area. These monocytes transitioned, in situ, from CCR2hiCx3CR1low to CX3CR1hiCCR2low within the ringlike structure and then entered the injury site. This phenotypic conversion was essential for optimal repair. These results demonstrate a local, cytokine driven reprogramming of classic, proinflammatory monocytes into nonclassical or alternative monocytes to facilitate proper wound-healing. PMID:25800956

CO 2-rich komatiitic melt inclusions in Cr-spinels within beach sand from Gorgona Island, Colombia

NASA Astrophysics Data System (ADS)

Shimizu, Kenji; Shimizu, Nobumichi; Komiya, Tsuyoshi; Suzuki, Katsuhiko; Maruyama, Shigenori; Tatsumi, Yoshiyuki

2009-10-01

The volatile content of komatiite is a key to constrain the thermal and chemical evolution of the deep Earth. We report the volatile contents with major and trace element compositions of ~ 80 melt inclusions in chromian spinels (Cr-spinels) from beach sands on Gorgona Island, Colombia. Gorgona Island is a ~ 90 Ma volcanic island, where picrites and the youngest komatiites known on the Earth are present. Melt inclusions are classified into three types on the basis of their host Cr-spinel compositions: low Ti (P type), high Ti with high Cr # (K1 type) and high Ti with low Cr # (K2 type). Chemical variations of melt inclusions in the Cr-spinels cover all of the island's lava types. P-type inclusions mainly occur in the picrites, K1-type in high-TiO 2 komatiites (some enriched basalts: E-basalts) and K2-type in low-TiO 2 komatiites. The H 2O and CO 2 contents of melt inclusions within Cr-spinels from the beach sand are highly variable (H 2O: 0.03-0.9 wt.%; CO 2: 40-4000 ppm). Evaluation of volatile content is not entirely successful because of compositional alterations of the original melt by degassing, seawater/brine assimilation and post-entrapment modification of certain elements and volatiles. However, the occurrence of many melt inclusions with low H 2O/K 2O ratios indicates that H 2O/K 2O of Gorgona komatiite is not much different from that of modern mid-oceanic ridge basalt (MORB) or oceanic island basalt. Trend of CO 2/Nb and Zr/Y ratios, accounted for by two-component mixing between the least degassed primary komatiite and low-CO 2/Nb evolved basalt, allow us to estimate a primary CO 2/Nb ratio of 4000 ± 2200 or a CO 2 content of 0.16 ± 0.09 wt.%. The determined CO 2/Nb ratio is unusually high, compared to that of MORB (530). Although the presence of CO 2 in the Gorgona komatiite does not affect the magma generation temperature, CO 2 degassing may have contributed to the eruption of high-density magmas. High CO 2/Nb and the relatively anhydrous nature of Gorgona komatiite provide possible resolution to one aspect of the hydrous komatiite debate.

Association Between Adjuvant Chemotherapy and Overall Survival in Patients With Rectal Cancer and Pathological Complete Response After Neoadjuvant Chemotherapy and Resection.

PubMed

Dossa, Fahima; Acuna, Sergio A; Rickles, Aaron S; Berho, Mariana; Wexner, Steven D; Quereshy, Fayez A; Baxter, Nancy N; Chadi, Sami A

2018-04-19

Although American guidelines recommend use of adjuvant chemotherapy in patients with locally advanced rectal cancer, individuals who achieve a pathological complete response (pCR) following neoadjuvant chemoradiotherapy are less likely to receive adjuvant treatment than incomplete responders. The association and resection of adjuvant chemotherapy with survival in patients with pCR is unclear. To determine whether patients with locally advanced rectal cancer who achieve pCR after neoadjuvant chemoradiation therapy and resection benefit from the administration of adjuvant chemotherapy. This retrospective propensity score-matched cohort study identified patients with locally advanced rectal cancer from the National Cancer Database from 2006 through 2012. We selected patients with nonmetastatic invasive rectal cancer who achieved pCR after neoadjuvant chemoradiation therapy and resection. We matched patients who received adjuvant chemotherapy to patients who did not receive adjuvant treatment in a 1:1 ratio. We separately matched subgroups of patients with node-positive disease before treatment and node-negative disease before treatment to investigate for effect modification by pretreatment nodal status. We compared overall survival between groups using Kaplan-Meier survival methods and Cox proportional hazards models. We identified 2455 patients (mean age, 59.5 years; 59.8% men) with rectal cancer with pCR after neoadjuvant chemoradiation therapy and resection. We matched 667 patients with pCR who received adjuvant chemotherapy and at least 8 weeks of follow-up after surgery to patients with pCR who did not receive adjuvant treatment. Over a median follow-up of 3.1 years (interquartile range, 1.94-4.40 years), patients treated with adjuvant chemotherapy demonstrated better overall survival than those who did not receive adjuvant treatment (hazard ratio, 0.44; 95% CI, 0.28-0.70). When stratified by pretreatment nodal status, only those patients with pretreatment node-positive disease exhibited improved overall survival with administration of adjuvant chemotherapy (hazard ratio, 0.24; 95% CI, 0.10-0.58). The administration of adjuvant chemotherapy in patients with rectal cancer with pCR is associated with improved overall survival, particularly in patients with pretreatment node-positive disease. Although this study suggests a beneficial effect of adjuvant treatment on survival in patients with pCR, these results are limited by the presence of potential unmeasured confounding in this nonrandomized study.

Distinction Between Recurrent Glioma and Radiation Injury Using Magnetic Resonance Spectroscopy in Combination With Diffusion-Weighted Imaging

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

Zeng, Q.-S.; Li, C.-F.; Liu Hong

2007-05-01

Purpose: The aim of this study was to explore the diagnostic effectiveness of magnetic resonance (MR) spectroscopy with diffusion-weighted imaging on the evaluation of the recurrent contrast-enhancing areas at the site of treated gliomas. Methods and Materials: In 55 patients who had new contrast-enhancing lesions in the vicinity of the previously resected and irradiated high-grade gliomas, two-dimensional MR spectroscopy and diffusion-weighted imaging were performed. Spectral data for N-acetylaspartate (NAA), choline (Cho), creatine (Cr), lipid (Lip), and lactate (Lac) were analyzed in conjunction with the apparent diffusion coefficient (ADC) in all patients. Diagnosis of these lesions was assigned by means ofmore » follow-up or histopathology. Results: The Cho/NAA and Cho/Cr ratios were significantly higher in recurrent tumor than in regions of radiation injury (p < 0.01). The ADC value and ADC ratios (ADC of contrast-enhancing lesion to matching structure in the contralateral hemisphere) were significantly higher in radiation injury regions than in recurrent tumor (p < 0.01). With MR spectroscopic data, two variables (Cho/NAA and Cho/Cr ratios) were shown to differentiate recurrent glioma from radiation injury, and 85.5% of total subjects were correctly classified into groups. However, with discriminant analysis of MR spectroscopy imaging plus diffusion-weighted imaging, three variables (Cho/NAA, Cho/Cr, and ADC ratio) were identified and 96.4% of total subjects were correctly classified. There was a significant difference between the diagnostic accuracy of the two discriminant analyses (Chi-square = 3.96, p = 0.046). Conclusion: Using discriminant analysis, this study found that MR spectroscopy in combination with ADC ratio, rather than ADC value, can improve the ability to differentiate recurrent glioma and radiation injury.« less

Protein sparing during general anesthesia with a propofol solution containing medium-chain triglycerides for gastrectomy: comparison with sevoflurane anesthesia.

PubMed

Nagao, Yoshiaki; Tatara, Tsuneo; Fujita, Kimihiko; Sugi, Takashi; Kotani, Joji; Hirose, Munetaka

2013-06-01

Despite the importance of the inhibition of catabolic response to surgery, the effects of different anesthetic techniques on the catabolic response in surgical patients are controversial. This study compared the endocrine-metabolic responses and protein catabolism during gastrectomy in patients who received either sevoflurane or propofol anesthesia with remifentanil. Thirty-seven patients (American Society of Anesthesiologists status I-III) aged 20-79 years undergoing elective gastrectomy were randomly assigned to receive sevoflurane anesthesia with remifentanil (n = 19) or intravenous propofol anesthesia (Propofol-Lipuro(®) 1 %; B. Braun, Melshungen AG, Germany) with remifentanil (n = 18). Urine samples were collected every 1 h after skin incision (0 h) and the urinary 3-methylhistidine:creatinine ratio (3-MH/Cr ratio) was used as a marker of protein catabolism. Respiratory quotient was measured during a 1 h period following skin incision. The 3-MH/Cr ratio significantly increased at 1-2 and 2-3 h compared to 0 and 0-1 h in both groups, but the propofol group exhibited a lower 3-MH/Cr ratio (nmol/μmol) than the sevoflurane group at 1-2 h (15.7 vs. 18.2, P = 0.012) and 2-3 h (15.9 vs. 18.1, P = 0.025). A difference was observed in the respiratory quotient between the sevoflurane and propofol groups (0.726 vs. 0.707, P = 0.003). A lower 3-MH/Cr ratio and a lower respiratory quotient during propofol anesthesia, compared to those exhibited during sevoflurane anesthesia, suggest that protein sparing probably occurs through the utilization of medium-chain triglycerides contained in the fat emulsion of propofol solution as a fuel source.

Effects of 2-year calorie restriction on circulating levels of IGF-1, IGF-binding proteins and cortisol in nonobese men and women: a randomized clinical trial.

PubMed

Fontana, Luigi; Villareal, Dennis T; Das, Sai K; Smith, Steven R; Meydani, Simin N; Pittas, Anastassios G; Klein, Samuel; Bhapkar, Manjushri; Rochon, James; Ravussin, Eric; Holloszy, John O

2016-02-01

Young-onset calorie restriction (CR) in rodents decreases serum IGF-1 concentration and increases serum corticosterone levels, which have been hypothesized to play major roles in mediating its anticancer and anti-aging effects. However, little is known on the effects of CR on the IGF-1 system and cortisol in humans. To test the sustained effects of CR on these key hormonal adaptations, we performed a multicenter randomized trial of a 2-year 25% CR intervention in 218 nonobese (body mass index between 22 and 27.8 kg m(-2) ) young and middle-aged (20-50 years age range) men and women. Average CR during the first 6 months was 19.5 ± 0.8% and 9.1 ± 0.7% over the next 18 months of the study. Weight loss averaged 7.6 ± 0.3 kg over the 2-years period of which 71% was fat mass loss (P < 0.0001). Average CR during the CR caused a significant 21% increase in serum IGFBP-1 and a 42% reduction in IGF-1:IGFBP-1 ratio at 2 years (P < 0.008), but did not change IGF-1 and IGF-1:IGFBP-3 ratio levels. Serum cortisol concentrations were slightly but significantly increased by CR at 1 year only (P = 0.003). Calorie restriction had no effect on serum concentrations of PDGF-AB and TGFβ-1. We conclude, on the basis of the present and previous findings, that, in contrast to rodents, humans do not respond to CR with a decrease in serum IGF-1 concentration or with a sustained and biological relevant increase in serum cortisol. However, long-term CR in humans significantly and persistently increases serum IGFBP-1 concentration. © 2015 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

CR108, a novel vitamin K3 derivative induces apoptosis and breast tumor inhibition by reactive oxygen species and mitochondrial dysfunction

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

Yang, Chun-Ru; Liao, Wei-Siang; Wu, Ya-Hui

Vitamin K3 derivatives have been shown to exert anticancer activities. Here we show a novel vitamin K3 derivative (S)-2-(2-hydroxy-3-methylbutylthio)naphthalene-1,4-dione, which is named as CR108 that induces apoptosis and tumor inhibition through reactive oxygen species (ROS) and mitochondrial dysfunction in human breast cancer. CR108 is more effective on the breast cancer cell death than other vitamin K3 derivatives. Moreover, CR108 induced apoptosis in both the non-HER-2-overexpressed MCF-7 and HER-2-overexpressed BT-474 breast cancer cells. CR108 caused the loss of mitochondrial membrane potential, cytochrome c released from mitochondria to cytosol, and cleaved PARP proteins for apoptosis induction. CR108 markedly increased ROS levels inmore » breast cancer cells. N-acetylcysteine (NAC), a general ROS scavenger, completely blocked the CR108-induced ROS levels, mitochondrial dysfunction and apoptosis. Interestingly, CR108 increased the phosphorylation of p38 MAP kinase but conversely inhibited the survivin protein expression. NAC treatment prevented the activation of p38 MAP kinase and rescued the survivin protein levels. SB202190, a specific p38 MAP kinase inhibitor, recovered the survivin protein levels and attenuated the cytotoxicity of CR108-treated cells. Furthermore, CR108 inhibited the xenografted human breast tumor growth in nude mice. Together, we demonstrate that CR108 is a novel vitamin K3 derivative that induces apoptosis and tumor inhibition by ROS production and mitochondrial dysfunction and associates with the phosphorylation of p38 MAP kinase and the inhibition of survivin in the human breast cancer. - Highlights: • CR108 is more effective on the cell death than other vitamin K3 derivatives. • CR108 induces apoptosis and tumor inhibition by ROS and mitochondrial dysfunction. • CR108 induces apoptosis by p38 kinase activation and survivin inhibition. • CR108 is a potent vitamin K3 analog that can develop for breast cancer therapy.« less

Variable convergence liquid layer implosions on the National Ignition Facility

DOE PAGES

Zylstra, A. B.; Yi, S. A.; Haines, B. M.; ...

2018-03-19

Liquid layer implosions using the “wetted foam” technique, where the liquid fuel is wicked into a supporting foam, have been recently conducted on the National Ignition Facility for the first time [Olson et al., Phys. Rev. Lett. 117, 245001 (2016)]. In this paper, we report on a series of wetted foam implosions where the convergence ratio was varied between 12 and 20. Reduced nuclear performance is observed as convergence ratio increases. 2-D radiation-hydrodynamics simulations accurately capture the performance at convergence ratios (CR) ~ 12, but we observe a significant discrepancy at CR ~ 20. Finally, this may be due tomore » suppressed hot-spot formation or an anomalous energy loss mechanism.« less

Variable convergence liquid layer implosions on the National Ignition Facility

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

Zylstra, A. B.; Yi, S. A.; Haines, B. M.

Liquid layer implosions using the “wetted foam” technique, where the liquid fuel is wicked into a supporting foam, have been recently conducted on the National Ignition Facility for the first time [Olson et al., Phys. Rev. Lett. 117, 245001 (2016)]. In this paper, we report on a series of wetted foam implosions where the convergence ratio was varied between 12 and 20. Reduced nuclear performance is observed as convergence ratio increases. 2-D radiation-hydrodynamics simulations accurately capture the performance at convergence ratios (CR) ~ 12, but we observe a significant discrepancy at CR ~ 20. Finally, this may be due tomore » suppressed hot-spot formation or an anomalous energy loss mechanism.« less

Metal Precursors and Reduction in Renazzo Chondrules

NASA Astrophysics Data System (ADS)

Zanda, B.; Hewins, R. H.; Bourot-Denise, M.

1993-07-01

The positive Co-Ni correlation and Cr, P contents of metal in CR chondrites have generally been taken to indicate their primitive nature, probably inherited from condensation [1,2]. Si in the metal of primitive chondrites has also been reported and interpreted as a condensation heritage [3,4]. However, Cr, P, and Si (dissolved or in the form of inclusions) in metal of any CR chondrule generally fall within a +-10% range, though large interchondrule variations exist [5]. We have shown that Cr and Si in metal are in equilibrium with Fo and En in silicates, due to the reducing conditions that prevailed during chondrule formation [6]. In the present paper, we show that the Co-Ni trend was also established during chondrule formation out of heterogeneous precursor material with a variable Co/Ni ratio. Chondrules in Renazzo are classified as highly molten (HM), in which metal has been expelled to form a mantle outside the chondrule, medium molten (MM), with metal inside and at the periphery, and with evidence for grain coalescence, and little melted (LM), in which metal is only present in the form of small blebs dispersed among the silicates. In HM chondrules, Ni and Co concentrations are extremely homogeneous, comparatively low and in the cosmic ratio. In LM chondrules, quite the opposite: Ni and Co spread over a large range and the amount of scatter increases with decreasing degree of melting of the chondrule. In addition, they do not correlate along the cosmic ratio, but show a negative correlation if any. This heterogeneity is present not only from grain to grain in these chondrules, but also in individual metal grains. Such a heterogeneity is also exhibited in Cr and P abundances that span a much larger range than the +-10% found in the other chondrules. These results indicate that chondrule formation is responsible for the homogenization of Co and Ni contents of metal grains through coalescence and mixing. The less melted objects give an idea of the nature of metal in chondrule precursors, extremely heterogeneous and fine grained (each small heterogeneous metal bleb might be the result of partial melting of one or of coalescence and imperfect mixing of a few such grains). Co and Ni in these individual grains were not in the cosmic ratio, but wide sampling of dust in each chondrule precursor insured that this ratio was attained after mixing and homogenization, as seen in HM chondrule metal grains and from mean values of Co and Ni in LM chondrules. In MM chondrules, scatter of Ni and Co data are, as expected, intermediate between those of HM and LM chondrules, but Co and Ni are close to the cosmic ratio. The scatter is mostly due to addition of variable quantities of iron in the reduction during chondrule formation, which is responsible for Cr and Si integration into metal. Further evidence of such a process can be found in the less molten of these objects, in which metal grain coalescence is limited and peripheral grains are still different from inside grains. In these cases, Co and Ni distributions are clearly bimodal, high in inside grains, low in peripheral grains. Co/Ni in these two populations are somewhat scattered around the cosmic ratio, but their means (Ni: 7.75 = +- 0.24, Co: 0.36 +- 0.04, and Ni: 4.39 +- 0.34, Co: 0.23 +- 0.02, e.g., in the case of chondrule AL1) are very close to the cosmic ratio. This is in good agreement with the low values found in the homogeneous mantle grains of HM chondrules and, as noted by Lee et al. [7], indicates that the reducing agent was external to the chondrule. Cr abundances of these peripheral metal grains, however, match Cr abundances of the interior ones in these chondrules. This indicates that the redox state of all these grains was attained simultaneously and controlled by equilibrium with chondrule silicates. Slightly more extensive reduction of the latter close to the chondrule surface that added more Fe to peripheral metal grains resulted in only a minor variation of the Cr partition coefficient: it consequently also induced Cr addition, the Cr/Fe ratio varying only marginally. Therefore, we believe unlike [7] the process to have been nebular, and the reducing agent the nebular gas, although equilibrium with this gas was clearly not attained. References: [1] Weisberg M. K. et al. (1993) GCA, 57, 1567-1586. [2] Grossman L. and Olsen E. (1974) GCA, 38, 173-187. [3] Grossman L., et al. (1979) Science, 206, 449-451. [4] Rambaldi E. R. et al. (1980) Nature, 287; Nature, 293, 558-561. [5] Zanda B. et al. (1991) LPSC XXII, 1543-1544. [6] Hewins R. H. and Zanda B. (1992) Meteoritics, 27, 233. [7] Lee M. S. et al. (1992) GCA, 56, 2521-2533.

Relation of structure to mechanical properties of thin thoria dispersion strengthened nickel-chromium (TD-NiCr alloy sheet

NASA Technical Reports Server (NTRS)

Whittenberger, J. D.

1975-01-01

A study of the relation between structure and mechanical properties of thin TD-NiCr sheet indicated that the elevated temperature tensile, stress-rupture, and creep strength properties depend primarily on the grain aspect ratio and sheet thickness. In general, the strength properties increased with increasing grain aspect ratio and sheet thickness. Tensile testing revealed an absence of ductility at elevated temperatures. A threshold stress for creep appears to exist. Even small amounts of prior creep deformation at elevated temperatures can produce severe creep damage.

New coordination compounds of Cr(III) used in leather tanning

NASA Astrophysics Data System (ADS)

Crudu, Marian; Sibiescu, Doina; Rosca, Ioan; Sutiman, Daniel; Vizitiu, Mihaela; Apostolescu, Gabriela

2009-01-01

Some new coordination compounds of Cr(III) using as ligand N-hydroxy - succinimide, were obtained and studied. The combination ratio, central atom: ligand were 1:1; 1:2 and 1:3. The new complex compounds were studied using UV-Vis spectroscopy, conductance and pH measurements. The studies of obtaining and of stability of the new compounds were accomplished in aqueous solutions using methods characteristic for coordination compounds: conductance and pH measurements. The combination ratios and the stability constants were determined with methods characteristic for studies in solutions.

An Investigation of Technologies for Hazardous Sludge Reduction at AFLC (Air Force Logistics Command) Industrial Waste Treatment Plants. Volume 2. Literature Review of Available Technologies for Treating Heavy Metal Wastewaters.

DTIC Science & Technology

1983-12-01

plate quality. Dummying of chromium baths is used in the special case where high cathode-to-anode 15ea ratio has resulted in build up of trivalent ... chromium (Cr ).Dummying with a high anode -to-cat hode area ratio can be used to reoxidize the trivalent to hexavalent chromium (Cr +6 ). Proper...the trivalent state, which then can be precipitated as chromium hydroxide by alkali neutralization " Cyanide oxidation (if needed) of segregated

Incident angle dependence of proton response of CR-39 (TS-16) track detector

NASA Technical Reports Server (NTRS)

Oda, K.; Csige, I.; Yamauchi, T.; Miyake, H.; Benton, E. V.

1993-01-01

The proton response of the TS-16 type of CR-39 plastic nuclear track detector has been studied with accelerated and fast neutron induced protons in vacuum and in air. The diameters of etched tracks were measured as a function of etching time and the etch rate ratio and the etch induction layer were determined from the growth curve of the diameter using a variable etch rate ratio model. In the case of the accelerated protons in vacuum an anomalous incident angle dependence of the response is observed.

Influence of pyrolysis temperature on properties and environmental safety of heavy metals in biochars derived from municipal sewage sludge.

PubMed

Jin, Junwei; Li, Yanan; Zhang, Jianyun; Wu, Shengchun; Cao, Yucheng; Liang, Peng; Zhang, Jin; Wong, Ming Hung; Wang, Minyan; Shan, Shengdao; Christie, Peter

2016-12-15

Dried raw sludge was pyrolyzed at temperatures ranging from 400 to 600°C at the increase of 50°C intervals to investigate the influence of pyrolysis temperature on properties and environmental safety of heavy metals in biochar derived from municipal sewage sludge. The sludge biochar yield decreased significantly with increasing pyrolysis temperature but the pH, ash content and specific surface area increased. Conversion of sludge to biochar markedly decreased the H/C and N/C ratios. FT-IR analysis confirmed a dramatic depletion of H and N and a higher degree of aromatic condensation in process of biochar formation at higher temperatures. The total concentrations of Cu, Zn, Pb, Cr, Mn, and Ni increased with conversion of sludge to biochar and increasing pyrolysis temperature. However, using BCR sequential extraction and analysis, it was found that most of the heavy metals existed in the oxizable and residual forms after pyrolysis, especially at 600°C, resulting in a significant reduction in their bioavailability, leading to a very low environmental risk of the biochar. The present study indicates pyrolysis is a promising sludge treatment method for heavy metals immobilization in biochar, and highlights the potential to minimize the harmful effects of biochar by controlling pyrolysis temperature. Copyright © 2016 Elsevier B.V. All rights reserved.

Oxidative Weathering of Earth's Surface 3.7 Billion Years ago? - A Chromium Isotope Perspective

NASA Astrophysics Data System (ADS)

Frei, R.; Crowe, S.; Bau, M.; Polat, A.; Fowle, D. A.; Døssing, L. N.

2015-12-01

The Great Oxidation Event signals the first large-scale oxygenation of the atmosphere roughly 2.4 Gyr ago. Geochemical signals diagnostic of oxidative weathering, however, extend as far back as 3.3-2.9 Gyr ago. 3.8-3.7 Gyr old rocks from Isua, Greenland stand as a deep time outpost, recording information on Earth's earliest surface chemistry and the low oxygen primordial biosphere. We find positive Cr isotope values (average δ53Cr = +0.05 +/- 0.10 permil; δ53Cr = (53Cr/52Cr)sample/(53Cr/52Cr)SRM 979 - 1) x 1000, where SRM 979 denotes Standard Reference Material 979 in both the Fe and Si-rich mesobands of 7 compositionally distinct quartz-magnetite and magnesian banded iron formation (BIF) samples collected from the eastern portion of the Isua BIF (Western Greenland). These postively fractioned Cr isotopes, relative to the igneous silicate Earth reservoir, in metamorphosed BIFs from Isua indicate oxidative Cr cycling 3.8-3.7 Gyr ago. We also examined the distribution of U, which is immobile in its reduced state but mobile when it is oxidized. Elevated U/Th ratios (mean U/Th ratio of 0.70 ± 0.29) in these BIFs relative to the contemporary crust, also signal oxidative mobilization of U. We suggest that reactive oxygen species (ROS) accumulated in Earth's surface environment inducing the oxidative weathering of rocks during the deposition of the Isua BIFs. The precise threshold atmospheric O2 concentrations for the induction of Cr isotope fractionation remain uncertain, but we argue that our data are consistent with the very low levels of oxygen or other ROS indicated by other proxies. Importantly, any trace of Cr that cycled through redox reactions on land would tend both to be heavy, and to mobilize into the contemporaneous run-off more readily than Cr weathered directly as Cr(III). Once having reached the oceans, this fractionated Cr would have been stripped from seawater by Fe (oxy)hydroxides formed during the deposition of BIFs from low oxygen oceans. The reactive oxygen species recorded in Isua sediments may also have been sufficient to support aerobic metabolisms, which are known to occur in extant bacteria at oxygen concentrations as low as 10-8 atm.

Long-term cortisol measures predict Alzheimer disease risk.

PubMed

Ennis, Gilda E; An, Yang; Resnick, Susan M; Ferrucci, Luigi; O'Brien, Richard J; Moffat, Scott D

2017-01-24

To examine whether long-term measures of cortisol predict Alzheimer disease (AD) risk. We used a prospective longitudinal design to examine whether cortisol dysregulation was related to AD risk. Participants were from the Baltimore Longitudinal Study of Aging (BLSA) and submitted multiple 24-hour urine samples over an average interval of 10.56 years. Urinary free cortisol (UFC) and creatinine (Cr) were measured, and a UFC/Cr ratio was calculated to standardize UFC. To measure cortisol regulation, we used within-person UFC/Cr level (i.e., within-person mean), change in UFC/Cr over time (i.e., within-person slope), and UFC/Cr variability (i.e., within-person coefficient of variation). Cox regression was used to assess whether UFC/Cr measures predicted AD risk. UFC/Cr level and UFC/Cr variability, but not UFC/Cr slope, were significant predictors of AD risk an average of 2.9 years before AD onset. Elevated UFC/Cr level and elevated UFC/Cr variability were related to a 1.31- and 1.38-times increase in AD risk, respectively. In a sensitivity analysis, increased UFC/Cr level and increased UFC/Cr variability predicted increased AD risk an average of 6 years before AD onset. Cortisol dysregulation as manifested by high UFC/Cr level and high UFC/Cr variability may modulate the downstream clinical expression of AD pathology or be a preclinical marker of AD. © 2016 American Academy of Neurology.

Creatine supplementation prevents fatty liver in rats fed choline-deficient diet: a burden of one-carbon and fatty acid metabolism.

PubMed

Deminice, Rafael; de Castro, Gabriela Salim Ferreira; Francisco, Lucas Vieira; da Silva, Lilian Eslaine Costa Mendes; Cardoso, João Felipe Rito; Frajacomo, Fernando Tadeu Trevisan; Teodoro, Bruno Gonzaga; Dos Reis Silveira, Leonardo; Jordao, Alceu Afonso

2015-04-01

To examine the effects of creatine (Cr) supplementation on liver fat accumulation in rats fed a choline-deficient diet. Twenty-four rats were divided into 3 groups of 8 based on 4 weeks of feeding an AIN-93 control diet (C), a choline-deficient diet (CDD) or a CDD supplemented with 2% Cr. The CDD diet was AIN-93 without choline. The CDD significantly increased plasma homocysteine and TNFα concentration, as well as ALT activity. In liver, the CDD enhanced concentrations of total fat (55%), cholesterol (25%), triglycerides (87%), MDA (30%), TNFα (241%) and decreased SAM concentrations (25%) and the SAM/SAH ratio (33%). Cr supplementation prevented all these metabolic changes, except for hepatic SAM and the SAM/SAH ratio. However, no changes in PEMT gene expression or liver phosphatidylcholine levels were observed among the three experimental groups, and there were no changes in hepatic triglyceride transfer protein (MTP) mRNA level. On the contrary, Cr supplementation normalized expression of the transcription factors PPARα and PPARγ that were altered by the CDD. Further, the downstream targets and fatty acids metabolism genes, UCP2, LCAD and CPT1a, were also normalized in the Cr group as compared to CDD-fed rats. Cr supplementation prevented fat liver accumulation and hepatic injures in rats fed with a CDD for 4 weeks. Our results demonstrated that one-carbon metabolism may have a small role in mitigating hepatic fat accumulation by Cr supplementation. The modulation of key genes related to fatty acid oxidation pathway suggests a new mechanism by which Cr prevents liver fat accumulation. Copyright © 2015 Elsevier Inc. All rights reserved.

Early Alzheimer's Disease Neuropathology Detected by Proton MR Spectroscopy

PubMed Central

Murray, Melissa E.; Przybelski, Scott A.; Lesnick, Timothy G.; Liesinger, Amanda M.; Spychalla, Anthony; Zhang, Bing; Gunter, Jeffrey L.; Parisi, Joseph E.; Boeve, Bradley F.; Knopman, David S.; Petersen, Ronald C.; Jack, Clifford R.; Dickson, Dennis W.

2014-01-01

Proton magnetic resonance spectroscopy (1H-MRS) is sensitive to early neurodegenerative processes associated with Alzheimer's disease (AD). Although 1H-MRS metabolite ratios of N-acetyl aspartate (NAA)/creatine (Cr), NAA/myoinositol (mI), and mI/Cr measured in the posterior cingulate gyrus reveal evidence of disease progression in AD, pathologic underpinnings of the 1H-MRS metabolite changes in AD are unknown. Pathologically diagnosed human cases ranging from no likelihood to high likelihood AD (n = 41, 16 females and 25 males) who underwent antemortem 1H-MRS of the posterior cingulate gyrus at 3 tesla were included in this study. Immunohistochemical evaluation was performed on the posterior cingulate gyrus using antibodies to synaptic vesicles, hyperphosphorylated tau (pTau), neurofibrillary tangle conformational-epitope (cNFT), amyloid-β, astrocytes, and microglia. The slides were digitally analyzed using Aperio software, which allows neuropathologic quantification in the posterior cingulate gray matter. MRS and pathology associations were adjusted for time from scan to death. Significant associations across AD and control subjects were found between reduced synaptic immunoreactivity and both NAA/Cr and NAA/mI in the posterior cingulate gyrus. Higher pTau burden was associated with lower NAA/Cr and NAA/mI. Higher amyloid-β burden was associated with elevated mI/Cr and lower NAA/mI ratios, but not with NAA/Cr. 1H-MRS metabolite levels reveal early neurodegenerative changes associated with AD pathology. Our findings support the hypothesis that a decrease in NAA/Cr is associated with loss of synapses and early pTau pathology, but not with amyloid-β or later accumulation of cNFT pathology in the posterior cingulate gyrus. In addition, elevation of mI/Cr is associated with the occurrence of amyloid-β plaques in AD. PMID:25471565

Coadsorption and subsequent redox conversion behaviors of As(III) and Cr(VI) on Al-containing ferrihydrite.

PubMed

Ding, Zecong; Fu, Fenglian; Dionysiou, Dionysios D; Tang, Bing

2018-04-01

Naturally occurring ferrihydrite often contains various impurities, and Al is one of the most prominent impurities. However, little is known about how these impurities impact the physical and chemical properties of ferrihydrite with respect to metal(loid) adsorption. In this study, a series of Al-containing ferrihydrites were synthesized and exposed to a mixed solution containing As(III) and Cr(VI). The results showed that the two contaminants can be quickly adsorbed onto the surface of Al-containing ferrihydrite under acidic and neutral conditions. With the increase of Al molar percentage in ferrihydrites from 0 to 30, the adsorption capacity of As(III) decreased, whereas it increased for Cr(VI). On the other hand, with the increase of pH value from 3.0 to 11.0, the decreasing rate of As(III) was accelerated first, then slowed down, whereas the Cr(VI) decreasing rate slowed down dramatically. X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis method, transmission electron microscopy (TEM) analysis, energy dispersive spectroscopy (EDS) mapping, Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS) were employed to characterize Al-containing ferrihydrite. Interestingly, it was found that the redox transformation occurred between As(III) and Cr(VI) after the two contaminants were coadsorbed onto the surface of Al-containing ferrihydrite. The oxidation of As(III) to As(V) and reduction of Cr(VI) to Cr(III) would greatly lower the environmental hazard of the As(III) and Cr(VI). Copyright © 2018 Elsevier Ltd. All rights reserved.

Chromium Trioxide Hole-Selective Heterocontacts for Silicon Solar Cells.

PubMed

Lin, Wenjie; Wu, Weiliang; Liu, Zongtao; Qiu, Kaifu; Cai, Lun; Yao, Zhirong; Ai, Bin; Liang, Zongcun; Shen, Hui

2018-04-25

A high recombination rate and high thermal budget for aluminum (Al) back surface field are found in the industrial p-type silicon solar cells. Direct metallization on lightly doped p-type silicon, however, exhibits a large Schottky barrier for the holes on the silicon surface because of Fermi-level pinning effect. As a result, low-temperature-deposited, dopant-free chromium trioxide (CrO x , x < 3) with high stability and high performance is first applied in a p-type silicon solar cell as a hole-selective contact at the rear surface. By using 4 nm CrO x between the p-type silicon and Ag, we achieve a reduction of the contact resistivity for the contact of Ag directly on p-type silicon. For further improvement, we utilize a CrO x (2 nm)/Ag (30 nm)/CrO x (2 nm) multilayer film on the contact between Ag and p-type crystalline silicon (c-Si) to achieve a lower contact resistance (40 mΩ·cm 2 ). The low-resistivity Ohmic contact is attributed to the high work function of the uniform CrO x film and the depinning of the Fermi level of the SiO x layer at the silicon interface. Implementing the advanced hole-selective contacts with CrO x /Ag/CrO x on the p-type silicon solar cell results in a power conversion efficiency of 20.3%, which is 0.1% higher than that of the cell utilizing 4 nm CrO x . Compared with the commercialized p-type solar cell, the novel CrO x -based hole-selective transport material opens up a new possibility for c-Si solar cells using high-efficiency, low-temperature, and dopant-free deposition techniques.

Preconception Maternal Iodine Status Is Positively Associated with IQ but Not with Measures of Executive Function in Childhood.

PubMed

Robinson, Sian M; Crozier, Sarah R; Miles, Elizabeth A; Gale, Catharine R; Calder, Philip C; Cooper, Cyrus; Inskip, Hazel M; Godfrey, Keith M

2018-05-15

Adverse effects of severe maternal iodine deficiency in pregnancy on fetal brain development are well-established, but the effects of milder deficiency are uncertain. Most studies examine iodine status in pregnancy; less is known about iodine nutrition before conception. We examined relations between maternal preconception iodine status and offspring cognitive function, within a prospective mother-offspring cohort. Maternal iodine status was assessed through the use of the ratio of iodine:creatinine concentrations (I/Cr) in spot urine samples [median (IQR) period before conception 3.3 y (2.2-4.7 y)]. Childhood cognitive function was assessed at age 6-7 y. Full-scale IQ was assessed via the Wechsler Abbreviated Scale of Intelligence, and executive function through the use of tests from the Cambridge Neuropsychological Test Automated Battery (CANTAB). Analyses (n = 654 mother-child dyads) were adjusted for potential confounders including maternal intelligence, education, and breastfeeding duration. The median (IQR) urinary iodine concentration was 108.4 µg/L (62.2-167.8 µg/L) and the I/Cr ratio 114 µg/g (76-164 µg/g). The preconception I/Cr ratio was positively associated with child IQ, before and after adjustment for potential confounding influences [β = 0.13 (95% CI: 0.04, 0.21)/SD, P = 0.003]. 8.9% of women had a preconception urinary I/Cr ratio <50 µg/g; compared with those with an I/Cr ratio ≥150 µg/g, the IQ of their offspring was 0.49 (95% CI: 0.79, 0.18) SD lower. There were no associations with the executive function outcomes assessed via CANTAB, before or after adjustment for confounders. The positive association between iodine status before conception and child IQ provides some support for demonstrated links between low maternal iodine status in pregnancy and poorer cognitive function reported in other studies. However, given the negative effects on school performance previously observed in children born to iodine-deficient mothers, the lack of associations with measures of executive function in the present study was unexpected. Further data are needed to establish the public health importance of low preconception iodine status.

7 Tesla proton magnetic resonance spectroscopic imaging in adult X-linked adrenoleukodystrophy

PubMed Central

Ratai, Eva; Kok, Trina; Wiggins, Christopher; Wiggins, Graham; Grant, Ellen; Gagoski, Borjan; O'Neill, Gilmore; Adalsteinsson, Elfar; Eichler, Florian

2010-01-01

Background Adult patients with X-linked adrenoleukodystrophy (X-ALD) remain at risk for progressive neurological deterioration. Phenotypes vary in their pathology, ranging from axonal degeneration to inflammatory demyelination. The severity of symptoms is poorly explained by conventional imaging. Objective To test the hypothesis that neurochemistry in normal appearing brain differs among adult phenotypes of X-ALD, and that neurochemical changes correlate with the severity of symptoms. Patients and Methods Using a 7 Tesla scanner we performed structural and proton MRSI in 13 adult patients with X-ALD, including 4 patients with adult cerebral ALD (ACALD), 5 with adrenomyeloneuropathy (AMN) and 4 female heterozygotes. Studies were also performed in nine healthy controls. Results Among adult X-ALD phenotypes, MI/Cr was 46% higher and Cho/Cr 21% higher in normal appearing white matter of ACALD compared to AMN (p < 0.05). Both NAA/Cr and Glu/Cr ratios were lower in AMN patients (p = 0.028 and p = 0.036, respectively) than in controls. There were no significant differences between AMN and female heterozygotes. In cortex, ACALD patients had lower values of NAA/Cr compared to female heterozygotes and controls (p = 0.022). The global MI/Cr ratio demonstrated a significant association with the EDSS (Spearman ρ = 0.66, p = 0.039). Conclusion 7 Tesla proton MRSI reveals differences in the neurochemistry of ACALD but is unable to distinguish AMN from female heterozygotes. MI/Cr correlates with the severity of the symptoms and may be a meaningful biomarker in adult X-ALD. PMID:19001168

Hydrogen-Resistant Fe/Ni/Cr-Base Superalloy

NASA Technical Reports Server (NTRS)

Bhat, Biliyar N.; Chen, Po-Shou; Panda, Binayak

1994-01-01

Strong Fe/Ni/Cr-base hydrogen- and corrosion-resistant alloy developed. Superalloy exhibits high strength and exceptional resistance to embrittlement by hydrogen. Contains two-phase microstructure consisting of conductivity precipitated phase in conductivity matrix phase. Produced in wrought, weldable form and as castings, alloy maintains high ductility and strength in air and hydrogen. Strength exceeds previously known Fe/Cr/Ni hydrogen-, oxidation-, and corrosion-resistant alloys. Provides higher strength-to-weight ratios for lower weight in applications as storage vessels and pipes that must contain hydrogen.

Site preference and compensation behavior in Co(Cr, Mn){sub 2}O{sub 4} system

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

Zhang, H. G.; College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124; Wang, Z.

Site preference of doped Mn ions in CoCr{sub 2−x}Mn{sub x}O{sub 4} (x = 0–2) series has been derived separately from structure and magnetic measurement. It shows that parts of the doped Mn ions occupy the A (Co) sites when x < 0.5. And then, it takes the two B (Cr) sites in turn before and after x = 1.3. This site preference behavior results in a role conversion of the magnetic contributors and, thus, leads to the composition dependent magnetic compensation. Temperature induced compensation and negative magnetization have also been found in several samples, which is attributed to the large energy barrier between the ferromagnetic andmore » antiferromagnetic spin arrangement. A structure transition from cubic to tetragonal symmetry has been detected.« less

Development of Simultaneous Corrosion Barrier and Optimized Microstructure in FeCrAl Heat-Resistant Alloy for Energy Applications. Part 1: The Protective Scale

NASA Astrophysics Data System (ADS)

Pimentel, G.; Aranda, M. M.; Chao, J.; González-Carrasco, J. L.; Capdevila, C.

2015-09-01

Coarse-grained Fe-based oxide dispersion-strengthened (ODS) steels are a class of advanced materials for combined cycle gas turbine systems to deal with operating temperatures and pressures of around 1100°C and 15-30 bar in aggressive environments, which would increase biomass energy conversion efficiencies up to 45% and above. This two-part paper reports the possibility of the development of simultaneous corrosion barrier and optimized microstructure in a FeCrAl heat-resistant alloy for energy applications. The first part reports the mechanism of generating a dense, self-healing α-alumina layer by thermal oxidation, during a heat treatment that leads to a coarse-grained microstructure with a potential value for high-temperature creep resistance in a FeCrAl ODS ferritic alloy, which will be described in more detail in the second part.

[Repercussions of chromium picolinate in the protein metabolism based on the age].

PubMed

González Muñoz, M J; Meseguer, I; Martínez Para, M C; Aguilar, M V; Bernao, A

2006-01-01

Commercialized like dietetic supplement, chromium picolinate has been promoted to favour the increase of muscle mass and the loss of weight, due to its' effect on the action of insulin. To evaluate the effect of supplementation of the diet with chromium (500 microg/kg) in the form of chromium picolinate (CrPic) (12 days) on growth and protein turnover in rats at different growth stages (infantile and puberal). No significant effect of CrPic on bodyweight gain, feed intake and feed conversion rate was observed at any of the stages of development studied. CrPic seems to increase the muscle mass, either by stimulating protein anabolism due to the involution of the insulin by chromium, or by reducing protein catabolism. Since the use of chromium picolinate could jeopardize the correct renal function and its' beneficial effects are not evident, it should always be consumed with caution.

Thermoelectric and magnetic properties of Cr-doped single crystal Bi2Se3 - Search for energy filtering

NASA Astrophysics Data System (ADS)

Cermak, P.; Ruleova, P.; Holy, V.; Prokleska, J.; Kucek, V.; Palka, K.; Benes, L.; Drasar, C.

2018-02-01

Thermoelectric effects are one of the promising ways to utilize waste heat. Novel approaches have appeared in recent decades aiming to enhance thermoelectric conversion. The theory of energy filtering of free carriers by inclusions is among the latest developed methods. Although the basic idea is clear, experimental evidence of this phenomenon is rare. Based on this concept, we searched suitable systems with stable structures showing energy filtering. Here, we report on the anomalous behavior of Cr-doped single-crystal Bi2Se3 that indicates energy filtering. The solubility of chromium in Bi2Se3 was studied, which is the key parameter in the formation process of inclusions. We present recent results on the effect of Cr-doping on the transport coefficients on a wide set of single crystalline samples. Magnetic measurements were used to corroborate the conclusions drawn from the transport and X-ray measurements.

Recruitment of single muscle fibers during submaximal cycling exercise.

PubMed

Altenburg, T M; Degens, H; van Mechelen, W; Sargeant, A J; de Haan, A

2007-11-01

In literature, an inconsistency exists in the submaximal exercise intensity at which type II fibers are activated. In the present study, the recruitment of type I and II fibers was investigated from the very beginning and throughout a 45-min cycle exercise at 75% of the maximal oxygen uptake, which corresponded to 38% of the maximal dynamic muscle force. Biopsies of the vastus lateralis muscle were taken from six subjects at rest and during the exercise, two at each time point. From the first biopsy single fibers were isolated and characterized as type I and II, and phosphocreatine-to-creatine (PCr/Cr) ratios and periodic acid-Schiff (PAS) stain intensities were measured. Cross sections were cut from the second biopsy, individual fibers were characterized as type I and II, and PAS stain intensities were measured. A decline in PCr/Cr ratio and in PAS stain intensity was used as indication of fiber recruitment. Within 1 min of exercise both type I and, although to a lesser extent, type II fibers were recruited. Furthermore, the PCr/Cr ratio revealed that the same proportion of fibers was recruited during the whole 45 min of exercise, indicating a rather constant recruitment. The PAS staining, however, proved inadequate to fully demonstrate fiber recruitment even after 45 min of exercise. We conclude that during cycling exercise a greater proportion of type II fibers is recruited than previously reported for isometric contractions, probably because of the dynamic character of the exercise. Furthermore, the PCr/Cr ratio method is more sensitive in determining fiber activation than the PAS stain intensity method.

Magnetic resonance spectroscopy of normal appearing white matter in early relapsing-remitting multiple sclerosis: correlations between disability and spectroscopy

PubMed Central

Ruiz-Peña, Juan Luis; Piñero, Pilar; Sellers, Guillermo; Argente, Joaquín; Casado, Alfredo; Foronda, Jesus; Uclés, Antonio; Izquierdo, Guillermo

2004-01-01

Background What currently appears to be irreversible axonal loss in normal appearing white matter, measured by proton magnetic resonance spectroscopy is of great interest in the study of Multiple Sclerosis. Our aim is to determine the axonal damage in normal appearing white matter measured by magnetic resonance spectroscopy and to correlate this with the functional disability measured by Multiple Sclerosis Functional Composite scale, Neurological Rating Scale, Ambulation Index scale, and Expanded Disability Scale Score. Methods Thirty one patients (9 male and 22 female) with relapsing remitting Multiple Sclerosis and a Kurtzke Expanded Disability Scale Score of 0–5.5 were recruited from four hospitals in Andalusia, Spain and included in the study. Magnetic resonance spectroscopy scans and neurological disability assessments were performed the same day. Results A statistically significant correlation was found (r = -0.38 p < 0.05) between disability (measured by Expanded Disability Scale Score) and N-Acetyl Aspartate (NAA/Cr ratio) levels in normal appearing white matter in these patients. No correlation was found between the NAA/Cr ratio and disability measured by any of the other disability assessment scales. Conclusions There is correlation between disability (measured by Expanded Disability Scale Score) and the NAA/Cr ratio in normal appearing white matter. The lack of correlation between the NAA/Cr ratio and the Multiple Sclerosis Functional Composite score indicates that the Multiple Sclerosis Functional Composite is not able to measure irreversible disability and would be more useful as a marker in stages where axonal damage is not a predominant factor. PMID:15191618

Talent Developed: Conversations with Masters in the Arts and Sciences. Eliot Feld.

ERIC Educational Resources Information Center

Subotnik, Rena F.

2002-01-01

In this interview, Eliot Feld, a ballet dancer who has choreographed more than 100 ballets for every major company in the United States and around the world, discusses his passion for dance, dance training, mentors, balancing academics and performance at the High School of Performing Arts, and establishing Ballet Tech. (CR)

Defects in hardwood timber

Treesearch

Roswell D. Carpenter; David L. Sonderman; Everette D. Rast; Martin J. Jones

1989-01-01

Includes detailed information on all common defects that may aRect hardwood trees and logs. Relationships between manufactured products and those forms of round material to be processed from the tree for conversion into marketable products are discussed. This handbook supersedes Agriculture Handbook No. 244, Grade defects in hardwood timber and logs, by C.R. Lockard, J...

Improving the Measurement of Cognitive Skills through Automated Conversations

ERIC Educational Resources Information Center

Jackson, G. Tanner; Castellano, Katherine E.; Brockway, Debra; Lehman, Blair

2018-01-01

Open-ended, short-answer questions, referred to as constructed responses (CR), allow students to express knowledge and skills through their own words. While CRs can reduce the likelihood of guessing correct answers, they also enable students to provide errant responses due to a lack of knowledge or a misunderstanding of the question.…

Comparison of in vivo genotoxic and carcinogenic potency to augment mode of action analysis: Case study with hexavalent chromium.

PubMed

Thompson, Chad M; Bichteler, Anne; Rager, Julia E; Suh, Mina; Proctor, Deborah M; Haws, Laurie C; Harris, Mark A

2016-04-01

Recent analyses-highlighted by the International Workshops on Genotoxicity Testing Working Group on Quantitative Approaches to Genetic Toxicology Risk Assessment-have identified a correlation between (log) estimates of a carcinogen's in vivo genotoxic potency and in vivo carcinogenic potency in typical laboratory animal models, even when the underlying data have not been matched for tissue, species, or strain. Such a correlation could have important implications for risk assessment, including informing the mode of action (MOA) of specific carcinogens. When in vivo genotoxic potency is weak relative to carcinogenic potency, MOAs other than genotoxicity (e.g., endocrine disruption or regenerative hyperplasia) may be operational. Herein, we review recent in vivo genotoxicity and carcinogenicity data for hexavalent chromium (Cr(VI)), following oral ingestion, in relevant tissues and species in the context of the aforementioned correlation. Potency estimates were generated using benchmark doses, or no-observable-adverse-effect-levels when data were not amenable to dose-response modeling. While the ratio between log values for carcinogenic and genotoxic potency was ≥1 for many compounds, the ratios for several Cr(VI) datasets (including in target tissue) were less than unity. In fact, the ratios for Cr(VI) clustered closely with ratios for chloroform and diethanolamine, two chemicals posited to have non-genotoxic MOAs. These findings suggest that genotoxicity may not play a major role in the cancers observed in rodents following exposure to high concentrations of Cr(VI) in drinking water-a finding consistent with recent MOA and adverse outcome pathway (AOP) analyses concerning Cr(VI). This semi-quantitative analysis, therefore, may be useful to augment traditional MOA and AOP analyses. More case examples will be needed to further explore the general applicability and validity of this approach for human health risk assessment. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Intermittent fasting results in tissue-specific changes in bioenergetics and redox state.

PubMed

Chausse, Bruno; Vieira-Lara, Marcel A; Sanchez, Angélica B; Medeiros, Marisa H G; Kowaltowski, Alicia J

2015-01-01

Intermittent fasting (IF) is a dietary intervention often used as an alternative to caloric restriction (CR) and characterized by 24 hour cycles alternating ad libitum feeding and fasting. Although the consequences of CR are well studied, the effects of IF on redox status are not. Here, we address the effects of IF on redox state markers in different tissues in order to uncover how changes in feeding frequency alter redox balance in rats. IF rats displayed lower body mass due to decreased energy conversion efficiency. Livers in IF rats presented increased mitochondrial respiratory capacity and enhanced levels of protein carbonyls. Surprisingly, IF animals also presented an increase in oxidative damage in the brain that was not related to changes in mitochondrial bioenergetics. Conversely, IF promoted a substantial protection against oxidative damage in the heart. No difference in mitochondrial bioenergetics or redox homeostasis was observed in skeletal muscles of IF animals. Overall, IF affects redox balance in a tissue-specific manner, leading to redox imbalance in the liver and brain and protection against oxidative damage in the heart.

Intermittent Fasting Results in Tissue-Specific Changes in Bioenergetics and Redox State

PubMed Central

Chausse, Bruno; Vieira-Lara, Marcel A.; Sanchez, Angélica B.; Medeiros, Marisa H. G.; Kowaltowski, Alicia J.

2015-01-01

Intermittent fasting (IF) is a dietary intervention often used as an alternative to caloric restriction (CR) and characterized by 24 hour cycles alternating ad libitum feeding and fasting. Although the consequences of CR are well studied, the effects of IF on redox status are not. Here, we address the effects of IF on redox state markers in different tissues in order to uncover how changes in feeding frequency alter redox balance in rats. IF rats displayed lower body mass due to decreased energy conversion efficiency. Livers in IF rats presented increased mitochondrial respiratory capacity and enhanced levels of protein carbonyls. Surprisingly, IF animals also presented an increase in oxidative damage in the brain that was not related to changes in mitochondrial bioenergetics. Conversely, IF promoted a substantial protection against oxidative damage in the heart. No difference in mitochondrial bioenergetics or redox homeostasis was observed in skeletal muscles of IF animals. Overall, IF affects redox balance in a tissue-specific manner, leading to redox imbalance in the liver and brain and protection against oxidative damage in the heart. PMID:25749501

Preparation and Corrosion Resistance of Trivalent Chromium-Zirconium Composite Coating

NASA Astrophysics Data System (ADS)

Huang, J. Z.

2018-05-01

Aluminum alloys are widely used in the various industries because of its superior advantages. However there will be a thin oxide layer on the surface of the pure aluminum to inhibit corrosion, when adding some other elements, the obtained aluminum alloy is easy to be corroded. Surface protection is an important means to improve the corrosion resistance of aluminum alloys. The formal research had already confirmed that the trivalent chromium conversion coating can significantly improve the corrosion resistance, and the usage of the zirconium solution can also protect the aluminum alloy from corrosion. In this study, we constructed the binary conversion coating with the Cr2(SO4)3 and the K2ZrF6. The optimum reaction conditions are as follows: 10g/L H3PO4, 2g/L K2ZrF6, 28g/L Cr2(SO4)3, pH=2.5∼3.5, temperature 40°C, and reaction time 10 min. Copper sulfate titration experiment confirmed that the corrosion resistance was significantly improved.

Deep Drawing Behavior of CoCrFeMnNi High-Entropy Alloys

NASA Astrophysics Data System (ADS)

Bae, Jae Wung; Moon, Jongun; Jang, Min Ji; Ahn, Dong-Hyun; Joo, Soo-Hyun; Jung, Jaimyun; Yim, Dami; Kim, Hyoung Seop

2017-09-01

Herein, the deep drawability and deep drawing behavior of an equiatomic CoCrFeMnNi HEA and its microstructure and texture evolution are first studied for future applications. The CoCrFeMnNi HEA is successfully drawn to a limit drawing ratio (LDR) of 2.14, while the planar anisotropy of the drawn cup specimen is negligible. The moderate combination of strain hardening exponent and strain rate sensitivity and the formation of deformation twins in the edge region play important roles in successful deep drawing. In the meanwhile, the texture evolution of CoCrFeMnNi HEA has similarities with conventional fcc metals.

Effect of self-absorption correction on surface hardness estimation of Fe-Cr-Ni alloys via LIBS.

PubMed

Ramezanian, Zahra; Darbani, Seyyed Mohammad Reza; Majd, Abdollah Eslami

2017-08-20

The effect of self-absorption was investigated on the estimation of surface hardness of Fe-Cr-Ni metallic alloys by the laser-induced breakdown spectroscopy (LIBS) technique. For this purpose, the linear relationship between the ratio of chromium ionic to atomic line intensities (CrII/CrI) and surface hardness was studied, both before and after correcting the self-absorption effect. The correlation coefficient significantly increased from 47% to 90% after self-absorption correction. The results showed the measurements of surface hardness using LIBS can be more accurate and valid by correcting the self-absorption effect.

Conservation and solar energy program: congressional budget request, FY 1982

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

None

1981-01-01

Funding summaries are presented for the Conservation and Solar Energy Program funding information and program overview on energy conservation (Volume 7 of 7, DOE/CR-0011/2) are included for the Buildings and Community Systems, Industrial, Transportation; State and Local, Multi-Sector, Energy Impact Assistance, and Residential/Commercial retrofit programs. Funding information and program overviews on solar technology (Volume 2 of 7, DOE/CR-011/2) are included for Active and Passive Solar Heating and Cooling, Photovoltaics Energy Systems, Solar Thermal Power Systems, Biomass Energy Systems, Wind Energy Conversion Systems, Ocean Systems, Solar International Activities, Solar Information Systems, SERI Facility, MX-RES, Program Direction, and Alcohol Fuels programs. Informationmore » and overviews on energy production, demonstration, and distribution (Volume 6 of 7, DOE/CR-0011/2) are given for the solar program. A funding summary and a program overview are included for electrochemical and physical and chemical storage systems as appearing in DOE/CR-0011/2, Volume 3 of 7. Relevant tabulated data from the FY 1981. Request to the Congress are presented for Supplementals, Rescissions, and Deferrals. (MCW)« less

Mineralogy and composition of matrix and chondrule rims in carbonaceous chondrites

NASA Technical Reports Server (NTRS)

Zolensky, Michael; Barrett, Ruth; Browning, Lauren

1993-01-01

The degree of compositional variation of fine-grained minerals displayed by the members within any carbonaceous chondrite group (i.e., CI, CM, CV, CR) is a direct reflection of the range of aqueous alteration assemblages present. Matrix and fine-grained chondrule rims within any particular carbonaceous chondrite are mineralogically nearly identical to one another, but not necessarily similar in bulk elemental composition, even though they have subsequently experienced postaccretional secondary processing (aqueous alteration) under identical conditions. We propose that CO chondrites experienced parent body conditions of low f(O2), low water/rock ratios, and temperatures below 50 C. CR chondrites experienced higher water/rock ratios, potentially higher temperatures (not above 150 C), and a wide range of f(O2). The alteration mineralogy of CV chondrites indicates water/rock ratios at the high end (at least) of the range for CR chondrites, Essebi, and MAC 87300. CM chondrites experienced temperatures below 50 C, low f(O2) and low water/rock ratios, except EET 83334, which probably experienced relatively higher f(O2), and B-7904 and Y-86720, which experienced postalteration temperatures in the range 500-700 C. Most CI chondrites experienced temperatures between 50 and 150 C, relatively high water/rock ratios, and variable f(O2). Y-82162 witnessed postalteration heating, possibly as high as 400 C.

[Conversion ratio between intravenous oxycodone/hydrocotarnine and sustained-release oral oxycodone in patients with cancer pain].

PubMed

Kokubun, Hideya; Nakamura, Kazuyo; Fukawa, Misako; Matoba, Motohiro; Hoka, Sumio; Yago, Kazuo

2007-12-01

The demand for oxycodone increases in the treatment of patients with cancer pain, but there is no injection formulation containing oxycodone as a single ingredient in Japan. Instead, we have an oxycodone/hydrocotarnine compound product. Long ago, hydrocotarnine was added to enhance the analgesic effect of oxycodone. However, the mechanism of hydrocotarnine is unclear, and few studies have mentioned the conversion ratio between intravenous and oral oxycodone. In the present study, in order to define the conversion ratio between them, we investigated 18 patients treated by intravenous or oral oxycodone and changed to another administration route during their treatment. We surveyed the change in pain level and adverse effects before and after changing the administration route. The conversion ratio from oral oxycodone to intravenous oxycodone/hydrocotarnine was 0.71+/-0.12 (mean+/-S. D.), and no obvious change in adverse effect was observed.

Metabolite alterations in basal ganglia associated with methamphetamine-related psychiatric symptoms. A proton MRS study.

PubMed

Sekine, Yoshimoto; Minabe, Yoshio; Kawai, Masayoshi; Suzuki, Katsuaki; Iyo, Masaomi; Isoda, Haruo; Sakahara, Harumi; Ashby, Charles R; Takei, Nori; Mori, Norio

2002-09-01

Following the chronic use of methamphetamine, some individuals experience psychosis and anxiety. One reason may be the persistence of metabolite abnormalities in the brain of currently abstinent former methamphetamine users. In this study, N-acetylaspartate (NAA), creatine plus phosphocreatine (Cr+PCr), and choline-containing compound (Cho) levels were measured in the left and right basal ganglia using proton magnetic resonance spectroscopy (MRS) in 13 abstinent methamphetamine users and 11 healthy comparison subjects with no history of illicit drug use. The methamphetamine users showed a significantly reduced Cr+PCr/Cho ratio in the bilateral basal ganglia compared with the healthy comparison subjects. Furthermore, the reduction in the Cr+PCr/Cho ratio was significantly correlated with the duration of methamphetamine use and with the severity of residual psychiatric symptoms. NAA/Cho ratios in the bilateral basal ganglia did not significantly differ between methamphetamine users and comparison subjects. These findings suggest that protracted use of methamphetamine may cause metabolite alterations in the basal ganglia. Furthermore, residual psychiatric symptoms may be attributable to the metabolite alterations in the basal ganglia.

Assessment of Possible Application of Geochemistry to Distinguish Limnic and Paralic Coal-Bearing Parts of the Carboniferous in the Upper Silesian Coal Basin

NASA Astrophysics Data System (ADS)

Kokowska-Pawłowska, Magdalena; Krzeszowska, Ewa

2017-12-01

The paper presents the results of geochemical analyses of samples from the Poruba Beds of the paralic series and from the Zaleskie Beds of the limnic series Upper Silesian Coal Basin (USCB). The contents of the following trace elements and oxides were evaluated using spectrometric method: Cr, Th, U, V, AL2O3, MgO, K2O, P2O5. The following indicators, most commonly used in chemostratigraphy and in the identification of the marine and non-marine sediments ratios, were analyzed: U, Th, Th/U, K2O, Th/K2O, P2O5, Al2O3, P2O5/ Al2O3, V, Cr, V/Cr, and (K2O/Al2O3) / (MgO/Al2O3). The research showed that those ratios may be used to identify sedimentary environments and geochemical correlations of the sedimentary rock sequences in the USCB. Geochemical ratios discussed in the paper allowed distinguishing two populations of samples representing paralic and limnic series.

Rescaling the complementary relationship for land surface evaporation

NASA Astrophysics Data System (ADS)

Crago, R.; Szilagyi, J.; Qualls, R.; Huntington, J.

2016-11-01

Recent research into the complementary relationship (CR) between actual and apparent potential evaporation has resulted in numerous alternative forms for the CR. Inspired by Brutsaert (2015), who derived a general CR in the form y = function (x), where x is the ratio of potential evaporation to apparent potential evaporation and y is the ratio of actual to apparent potential evaporation, an equation is proposed to calculate the value of x at which y goes to zero, denoted xmin. The value of xmin varies even at an individual observation site, but can be calculated using only the data required for the Penman (1948) equation as expressed here, so no calibration of xmin is required. It is shown that the scatter in x-y plots using experimental data is reduced when x is replaced by X = (x - xmin)/(1 - xmin). This rescaling results in data falling along the line y = X, which is proposed as a new version of the CR. While a reinterpretation of the fundamental boundary conditions proposed by Brutsaert (2015) is required, the physical constraints behind them are still met. An alternative formulation relating y to X is also discussed.

Dorsolateral prefrontal cortex N-acetylaspartate/total creatine (NAA/tCr) loss in male recreational cannabis users.

PubMed

Hermann, Derik; Sartorius, Alexander; Welzel, Helga; Walter, Sigrid; Skopp, Gisela; Ende, Gabriele; Mann, Karl

2007-06-01

Cannabinoids present neurotoxic and neuroprotective properties in in vitro studies, inconsistent alterations in human neuroimaging studies, neuropsychological deficits, and an increased risk for psychotic episodes. Proton magnetic resonance spectroscopy ((1)H-MRS), neuropsychological testing, and hair analysis for cannabinoids was performed in 13 male nontreatment-seeking recreational cannabis users and 13 male control subjects. A significantly diminished N-acetylaspartate/total creatine (NAA/tCr) ratio in the dorsolateral prefrontal cortex (DLPFC) was observed in cannabis users (p = .0003). The NAA/tCr in the putamen/globus pallidum region correlated significantly with cannabidiol (R(2) = .66, p = .004). Results of the Wisconsin Card Sorting test, Trail making Test, and D2 test for attention were influenced by cannabinoids. Chronic recreational cannabis use is associated with an indication of diminished neuronal and axonal integrity in the DLPFC in this study. As chronic cannabis use is a risk factor for psychosis, these results are interesting because diminished NAA/tCr ratios in the DLPFC and neuropsychological deficits were also reported in schizophrenia. The strong positive correlation of NAA/tCr and cannabidiol in the putamen/globus pallidum is in line with neuroprotective properties of cannabidiol, which were also observed in in vitro model studies of Parkinson's disease.

Green synthesis of tannin-hexamethylendiamine based adsorbents for efficient removal of Cr(VI).

PubMed

Liu, Qiang; Liu, Qinze; Liu, Bingsi; Hu, Tao; Liu, Weiliang; Yao, Jinshui

2018-06-15

Newly developed adsorbents, poly(tannin-hexamethylendiamine) (PTHA), were fabricated by varying the mole ratio of tannin (TA) and hexamethylendiamine (HA) under one-pot reaction. The specific forming process of the adsorbent which had undergone the transition from hydrogen bonds to covalent bonds was subsequently explored. Based on the efficiency of Cr(VI) removal from aqueous solution over all prepared adsorbents, the PTHA-4 (mole ratio of TA/HA = 1:12.5) exhibited an excellent adsorption behavior. Adsorption experiments affected by contact time and ionic strength have been conducted successively by PTHA-4, and the equilibrium was reached at 24 h. The kinetic data revealed that the adsorption was good agreement with pseudo-second order model and needed to undergo the rate-controlling step. The maximum adsorption capacity was 283.29 mg/g at 30 °C, relying on the isothermal curve suitably described by Langmuir model. Furthermore, toxic Cr(VI) had been reduced to the low toxic Cr(III) during adsorption process. The structures and adsorption performance of adsorbent were confirmed by means of SEM, FT-IR, XPS etc. Thus, the cheap-sustainable adsorbents have a superior feature for Cr(VI)-wastewater purification in future. Copyright © 2018 Elsevier B.V. All rights reserved.

Positron emission tomography-guided magnetic resonance spectroscopy in Alzheimer disease.

PubMed

Sheikh-Bahaei, Nasim; Sajjadi, S Ahmad; Manavaki, Roido; McLean, Mary; O'Brien, John T; Gillard, Jonathan H

2018-04-01

To determine whether the level of metabolites in magnetic resonance spectroscopy (MRS) is a representative marker of underlying pathological changes identified in positron emission tomographic (PET) images in Alzheimer disease (AD). We performed PET-guided MRS in cases of probable AD, mild cognitive impairment (MCI), and healthy controls (HC). All participants were imaged by 11 C-Pittsburgh compound B ( 11 C-PiB) and 18 F-fluorodeoxyglucose ( 18 F-FDG) PET followed by 3T MRS. PET images were assessed both visually and using standardized uptake value ratios (SUVRs). MRS voxels were placed in regions with maximum abnormality on amyloid (Aβ+) and FDG (hypometabolic) areas on PET scans. Corresponding normal areas were selected in controls. The ratios of total N-acetyl (tNA) group, myoinositol (mI), choline, and glutamate + glutamine over creatine (Cr) were compared between these regions. Aβ + regions had significantly higher (p = 0.02) mI/Cr and lower tNA/Cr (p = 0.02), whereas in hypometabolic areas only tNA/Cr was reduced (p = 0.003). Multiple regression analysis adjusting for sex, age, and education showed mI/Cr was only associated with 11 C-PiB SUVR (p < 0.0001). tNA/Cr, however, was associated with both PiB (p = 0.0003) and 18 F-FDG SUVR (p = 0.006). The level of mI/Cr was not significantly different between MCI and AD (p = 0.28), but tNA/Cr showed significant decline from HC to MCI to AD (p = 0.001, p = 0.04). mI/Cr has significant temporal and spatial associations with Aβ and could potentially be considered as a disease state biomarker. tNA is an indicator of early neurodegenerative changes and might have a role as disease stage biomarker and also as a valuable surrogate marker for treatment response. Ann Neurol 2018;83:771-778. © 2018 American Neurological Association.

The Use of Chromium(III) to Supercharge Peptides by Protonation at Low Basicity Sites

NASA Astrophysics Data System (ADS)

Feng, Changgeng; Commodore, Juliette J.; Cassady, Carolyn J.

2015-02-01

The addition of chromium(III) nitrate to solutions of peptides with seven or more residues greatly increases the formation of doubly protonated peptides, [M + 2H]2+, by electrospray ionization. The test compound heptaalanine has only one highly basic site (the N-terminal amino group) and undergoes almost exclusive single protonation using standard solvents. When Cr(III) is added to the solution, abundant [M + 2H]2+ forms, which involves protonation of the peptide backbone or the C-terminus. Salts of Al(III), Mn(II), Fe(III), Fe(II), Cu(II), Zn (II), Rh(III), La(III), Ce(IV), and Eu(III) were also studied. Although several metal ions slightly enhance protonation, Cr(III) has by far the greatest ability to generate [M + 2H]2+. Cr(III) does not supercharge peptide methyl esters, which suggests that the mechanism involves interaction of Cr(III) with a carboxylic acid group. Other factors may include the high acidity of hexa-aquochromium(III) and the resistance of Cr(III) to reduction. Nitrate salts enhance protonation more than chloride salts and a molar ratio of 10:1 Cr(III):peptide produces the most intense [M + 2H]2+. Cr(III) also supercharges numerous other small peptides, including highly acidic species. For basic peptides, Cr(III) increases the charge state (2+ versus 1+) and causes the number of peptide molecules being protonated to double or triple. Chromium(III) does not supercharge the proteins cytochrome c and myoglobin. The ability of Cr(III) to enhance [M + 2H]2+ intensity may prove useful in tandem mass spectrometry because of the resulting overall increase in signal-to-noise ratio, the fact that [M + 2H]2+ generally dissociate more readily than [M + H]+, and the ability to produce [M + 2H]2+ precursors for electron-based dissociation techniques.

Experimental modeling of Au and Pt coupled transport by chloride hydrothermal fluids at 350-450°C and 500-1000 bar

NASA Astrophysics Data System (ADS)

Zotov, A. V.; Tagirov, B. R.; Koroleva, L. A.; Volchenkova, V. A.

2017-09-01

The coupled solubility of Au(cr) and Pt(cr) has been measured in acidic chloride solutions at 350-450°C and 0.5 and 1 kb using the autoclave technique with determination of dissolved metal contents after quenching. The constants of the reaction combining the dominant species of Au and Pt in high-temperature hydrothermal fluids ( K (Au-Pt)) have been determined: 2 Au(cr) + PtCl4 2- = Pt(cr) + 2AuCl2 -; log K (Au-Pt) =-1.02 ± 0.25 (450°C, 1 kb), 0.09 ± 0.15 (450°C, 0.5 kb), and -1.31 ± 0.20 (350°C, 1 kb). It has been established that the factors affecting the Au/Pt concentration ratio in hydrothermal fluids and precipitated ores are temperature, pressure, redox potential, and sulfur fugacity. An increase in temperature results in an increase in the Au/Pt concentration ratio (up to 550°C at P = 1 kb). A decrease in pressure and redox potential leads to enrichment of fluid in Au. An increase in sulfur fugacity in the stability field of Pt sulfides results in increase in the Au/Pt concentration ratio. Native platinum is replaced by sulfide mineral in low-temperature systems enriched in Pt (relative to Au).

Myo-inositol metabolism in appropriately grown and growth-restricted fetuses: a proton magnetic resonance spectroscopy study.

PubMed

Story, Lisa; Damodaram, Mellisa S; Supramaniam, Veena; Allsop, Joanna M; Mcguinness, Amy; Patel, Abhilasha; Wylezinska, Marzena; Kumar, Sailesh; Rutherford, Mary A

2013-09-01

Myo-inositol (Myo-ins) is a marker of neuroglial cells, being present in the astrocytes of brain tissue, but also functions as an osmolyte. Numbers of astrocytes are known to increase following injury to the brain. Growth-restricted fetuses are at increased risk of later neurodevelopmental impairments even in the absence of overt lesions and despite preserved/increased cerebral blood flow. This study aims to investigate brain Myo-ins metabolism in fetuses with intrauterine growth restriction (IUGR) and evidence of cerebral redistribution using magnetic resonance spectroscopy (MRS) at a short echo time. Biometry and Doppler assessment of blood flow was assessed using ultrasound in 28 fetuses with IUGR and 47 appropriately grown control subjects. MRI was used to exclude overt brain injury. Proton magnetic resonance spectroscopy of the fetal brain was then performed at an echo time of 42 ms to examine the Myo-ins:Choline (Cho), Myo-ins:Creatine (Cr) and Cho:Cr ratios. No alterations in brain Myo-ins:Cho, Myo-ins:Cr or Cho:Cr ratios were detected between appropriately grown and growth restricted fetuses. IUGR is not associated with a measureable difference in brain myo-inositol ratios. This may be due to the protective effects of preserved cerebral blood flow in growth restriction and comparable astrocyte numbers when compared to controls. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Reduced NAA-levels in the NAWM of patients with MS is a feature of progression. A study with quantitative magnetic resonance spectroscopy at 3 Tesla.

PubMed

Aboul-Enein, Fahmy; Krssák, Martin; Höftberger, Romana; Prayer, Daniela; Kristoferitsch, Wolfgang

2010-07-20

Reduced N-acetyl-aspartate (NAA) levels in magnetic resonance spectroscopy (MRS) may visualize axonal damage even in the normal appearing white matter (NAWM). Demyelination and axonal degeneration are a hallmark in multiple sclerosis (MS). To define the extent of axonal degeneration in the NAWM in the remote from focal lesions in patients with relapsing-remitting (RRMS) and secondary progressive MS (SPMS). 37 patients with clinical definite MS (27 with RRMS, 10 with SPMS) and 8 controls were included. We used 2D (1)H-MR-chemical shift imaging (TR = 1500ms, TE = 135ms, nominal resolution 1ccm) operating at 3Tesla to assess the metabolic pattern in the fronto-parietal NAWM. Ratios of NAA to creatine (Cr) and choline (Cho) and absolute concentrations of the metabolites in the NAWM were measured in each voxel matching exclusively white matter on the anatomical T2 weighted MR images. No significant difference of absolute concentrations for NAA, Cr and Cho or metabolite ratios were found between RRMS and controls. In SPMS, the NAA/Cr ratio and absolute concentrations for NAA and Cr were significantly reduced compared to RRMS and to controls. In our study SPMS patients, but not RRMS patients were characterized by low NAA levels. Reduced NAA-levels in the NAWM of patients with MS is a feature of progression.

Mineral chemistry and geochemistry of ophiolitic metaultramafics from Um Halham and Fawakhir, Central Eastern Desert, Egypt

NASA Astrophysics Data System (ADS)

Abdel-Karim, Abdel-Aal M.; Ali, Shehata; El-Shafei, Shaimaa A.

2018-03-01

This study is focused on ophiolitic metaultramafics from Um Halham and Fawakhir, Central Eastern Desert of Egypt. The rocks include serpentinized peridotites, serpentinites together with talc- and quartz-carbonates. The primary spinel relict is Al-chromite [Cr# > 60], which is replaced by Cr-magnetite during metamorphism. The high Cr# of Al-chromites resembles supra-subduction zone (SSZ) peridotites and suggests derivation from the deeper portion of the mantle section with boninitic affinity. These mantle rocks equilibrated with boninitic melt have been generated by high melting degrees. The estimated melting degrees ( 19-24%) lie within the range of SSZ peridotites. The high Cr# of spinel and Fo content of olivine together with the narrow compositional range suggest a mantle residual origin. Serpentinized peridotite and serpentinites have low Al2O3/SiO2 ratios (mostly < 0.03) like fore-arc mantle wedge serpentinites and further indicate that their mantle protolith had experienced partial melting before serpentinization process. Moreover, they have very low Nb, Ta, Zr and Hf concentrations along with sub-chondritic Nb/Ta (0.3-16) and Zr/Hf (mostly 1-20) ratios further confirming that their mantle source was depleted by earlier melting extraction event. The high chondrite normalized (La/Sm)N ratios (average 10) reflect input of subduction-related slab melts/fluids into their mantle source.

Influence of COD/sulfate ratios on the integrated reactor system for simultaneous removal of carbon, sulfur and nitrogen.

PubMed

Yuan, Ye; Chen, Chuan; Zhao, Youkang; Wang, Aijie; Sun, Dezhi; Huang, Cong; Liang, Bin; Tan, Wenbo; Xu, Xijun; Zhou, Xu; Lee, Duu-Jung; Ren, Nanqi

2015-01-01

An integrated reactor system was developed for the simultaneous removal of carbon, sulfur and nitrogen from sulfate-laden wastewater and for elemental sulfur (S°) reclamation. The system mainly consisted of an expanded granular sludge bed (EGSB) for sulfate reduction and organic carbon removal (SR-CR), an EGSB for denitrifying sulfide removal (DSR), a biological aerated filter for nitrification and a sedimentation tank for sulfur reclamation. This work investigated the influence of chemical oxygen demand (COD)/sulfate ratios on the performance of the system. Influent sulfate and ammonium were fixed to the level of 600 mg SO(4)(2-) L⁻¹ and 120 mg NH(4)(+) L⁻¹, respectively. Lactate was introduced to generate COD/SO(4)(2-) = 0.5:1, 1:1, 1.5:1, 2:1, 3:1, 3.5:1 and 4:1. The experimental results indicated that sulfate could be efficiently reduced in the SR-CR unit when the COD/SO(4)(2-) ratio was between 1:1 and 3:1, and sulfate reduction was inhibited by the growth of methanogenic bacteria when the COD/SO(4)(2-) ratio was between 3.5:1 and 4:1. Meanwhile, the Org-C/S²⁻/NO(3)(-) ratios affected the S(0) reclamation efficiency in the DSR unit. When the influent COD/SO(4)(2-) ratio was between 1:1 and 3:1, appropriate Org-C/S²⁻/NO(3)(-) ratios could be achieved to obtain a maximum S° recovery in the DSR unit. For the microbial community of the SR-CR unit at different COD/SO(4)(2-) ratios, 16S rRNA gene-based high throughput Illumina MiSeq sequencing was used to analyze the diversity and potential function of the dominant species.

A soft-switching coupled inductor bidirectional DC-DC converter with high-conversion ratio

NASA Astrophysics Data System (ADS)

Chao, Kuei-Hsiang; Jheng, Yi-Cing

2018-01-01

A soft-switching bidirectional DC-DC converter is presented herein as a way to improve the conversion efficiency of a photovoltaic (PV) system. Adoption of coupled inductors enables the presented converter not only to provide a high-conversion ratio but also to suppress the transient surge voltage via the release of the energy stored in leakage flux of the coupled inductors, and the cost can kept down consequently. A combined use of a switching mechanism and an auxiliary resonant branch enables the converter to successfully perform zero-voltage switching operations on the main switches and improves the efficiency accordingly. It was testified by experiments that our proposed converter works relatively efficiently in full-load working range. Additionally, the framework of the converter intended for testifying has high-conversion ratio. The results of a test, where a generating system using PV module array coupled with batteries as energy storage device was used as the low-voltage input side, and DC link was used as high-voltage side, demonstrated our proposed converter framework with high-conversion ratio on both high-voltage and low-voltage sides.

Cr-Si Schottky nano-diodes utilizing anodic aluminum oxide templates.

PubMed

Kwon, Namyong; Kim, Kyohyeok; Heo, Jinhee; Chung, Ilsub

2014-04-01

We have fabricated Cr nanodot Schottky diodes utilizing AAO templates formed on n-Si substrates. The diameters of the diodes were 75.0, 57.6, and 35.8 nm. Cr nanodot Schottky diodes with smaller diameters yield higher current densities than those with larger diameters due to an enhanced tunnel current contribution, which is attributed to a reduction in the barrier thickness. The diameters of Cr nanodots smaller than the Debye length (156 nm) play an important role in the reduction of barrier thickness. Also, we have fabricated Cr-Si nanorod Schottky diodes with three different lengths (130, 220, and 330 nm) by dry etching of n-Si substrate. Cr-Si nanorod Schottky diodes with longer nanorods yield higher reverse current than those with shorter nanorods due to the enhanced electric field, which is attributed to a high aspect ratio of Si nanorod.

Eutectic equilibria in the quaternary system Fe-Cr-Mn-C

NASA Technical Reports Server (NTRS)

Nowotny, H.; Wayne, S.; Schuster, J. C.

1982-01-01

The constitution of the quaternary system, Fe-Cr-Mn-C and to a lesser extent of the quinary system, Fe-Cr-Mn-Al-C were examined for in situ composite alloy candidates. Multivariant eutectic compositions were determined from phase equilibria studies wherein M7C3 carbides (approximately 30% by volume) formed from the melt within gamma iron. An extended field of the hexagonal carbide, (Cr, Fe, Mn)7 C3, was found without undergoing transformation to the orthorhombic structure. Increasing stability for this carbide was found for higher ratios of Cr/Fe(+) Cr + Mn. Aluminum additions promoted a ferritic matrix while manganese favored the desired gamma austenitic matrix. In coexistence with the matrix phase, chromium enters preferentially the carbide phase while manganese distributes equally between the gamma matrix and the M7C3 carbide. The composition and lattice parameters of the carbide and matrix phases were determined to establish their respective stabilities.

Estimation of glomerular filtration rate in cancer patients with abnormal body composition and relation with carboplatin toxicity.

PubMed

Bretagne, M; Jouinot, A; Durand, J P; Huillard, O; Boudou Rouquette, P; Tlemsani, C; Arrondeau, J; Sarfati, G; Goldwasser, F; Alexandre, J

2017-07-01

Carboplatin clearance is correlated with glomerular filtration rate (GFR) and usually estimated with creatinine clearance using Cockcroft-Gault (CG) formula. Because plasma creatinine level is highly correlated with muscle mass, we hypothesized that an abnormal body composition with a low lean body mass (LBM) percentage [(LBM/weight) × 100] may result in inadequate carboplatin dosing. Serum cystatin C is an alternative marker of GFR, not affected by muscle mass. We aimed to investigate the influence of total LBM and LBM percentage on GFR calculation, using creatinine (CrCl) or cystatin C (GFR cysC-creat ) in cancer patients. Pretreatment serum creatinine and cystatin C were prospectively measured in consecutive patients. CrCl (CG formula), GFR cysC-creat (CKD-EPI creatinine-cystatin equation), and LBM (CT scan) were calculated. Severe thrombocytopenia post-carboplatin were analyzed. In 131 patients without renal insufficiency, LBM was correlated with creatinine (r = 0.30, p < 0.005) but not with cystatin C (r = -0.07, p = 0.43). In patients with the lowest LBM percentage, the CrCl was significantly higher than GFR cysC-creat indicating an overestimation of GFR with creatinine (p = 0.0004). In 24 patients treated with carboplatin AUC 5 (mg/ml min) ± paclitaxel, the risk of severe thrombocytopenia was associated with lower LBM percentage (p = 0.0002) and higher CrCl/GFR cysC-creat ratio (p = 0.006). By ROC analysis, the CrCl/GFR cysC-creat ratio threshold predicting severe thrombocytopenia was 1.23. A low LBM percentage increases the risk of inadequate GFR calculation by CG formula, and carboplatin overdosage with severe thrombocytopenia. High CrCl/GFR cysC-creat ratio allows the identification of these patients.

9 Cr-- 1 Mo steel material for high temperature application

DOEpatents

Jablonski, Paul D; Alman, David; Dogan, Omer; Holcomb, Gordon; Cowen, Christopher

2012-11-27

One or more embodiments relates to a high-temperature, titanium alloyed, 9 Cr-1 Mo steel exhibiting improved creep strength and oxidation resistance at service temperatures up to 650.degree. C. The 9 Cr-1 Mo steel has a tempered martensite microstructure and is comprised of both large (0.5-3 .mu.m) primary titanium carbides and small (5-50 nm) secondary titanium carbides in a ratio of. from about 1:1.5 to about 1.5:1. The 9 Cr-1 Mo steel may be fabricated using exemplary austenizing, rapid cooling, and tempering steps without subsequent hot working requirements. The 9 Cr-1 Mo steel exhibits improvements in total mass gain, yield strength, and time-to-rupture over ASTM P91 and ASTM P92 at the temperature and time conditions examined.

Antiproton Production by CR on Air Nuclei

NASA Technical Reports Server (NTRS)

Maskalenko, I. V.; Mashnik, S. G.

2003-01-01

Recent measurements of the cosmic ray (CR) antiproton flux have been shown to challenge existing CR propagation models. In particular, the conventional reacceleration model designed to match secondary/primary nuclei ratios produces too few antiprotons. Recently there appear some indications that the atmospheric contribution to antiproton production is considerably underestimated, which implies that antiproton CR flux might be lower. This may be the primary reason of the discrepancy discovered in CR propagation. We use the Los Alamos version of the Quark-Gluon String Model code LAQGSM together with available data on antiproton production on nuclei to analyse the accuracy of existing parameterizations of antiproton production cross section. The LAQGSM model has been shown to reproduce well nuclear reactions and hadronic data in the range 0.01-800 GeV/nucleon.

Australasian microtektites: Impactor identification using Cr, Co and Ni ratios

NASA Astrophysics Data System (ADS)

Folco, L.; Glass, B. P.; D'Orazio, M.; Rochette, P.

2018-02-01

Impactor identification is one of the challenges of large-scale impact cratering studies due to the dilution of meteoritic material in impactites (typically < 1 wt%). The nature of the impactor that generated the Australasian tektite/microtektite strewn field, i.e., the largest Cenozoic strewn field (∼15% of the Earth's surface), the youngest (∼0.78 Myr old) on Earth, and the only one without an associated impact crater so far, is an outstanding issue. We identify a chondritic impactor signature in 77 Australasian microtektites (size range: ∼200-700 μm) from within 3000 km from the hypothetical impact location in Indochina (∼17°N, 107°E) based on variations of Cr, Co and Ni interelement ratios in a Co/Ni vs Cr/Ni space (46 microtektites analyzed in this work by Laser Ablation-Inductively Coupled Plasma -Mass Spectrometry and 31 from literature by means of Neutron Activation Analyses with Cr, Co and Ni concentrations up to ∼370, 50 and 680 μg/g, respectively). Despite substantial overlap in Cr/Ni versus Co/Ni composition for several meteorite types with chondritic composition (chondrites and primitive achondrites), regression calculation based on ∼85% of the studied microtektites best fit a mixing line between crustal compositions and an LL chondrite. However, due to some scatter mainly in the Cr versus Ni ratios in the considered dataset, an LL chondrite may not be the best fit to the data amongst impactors of primitive compositions. Eight high Ni/Cr and five low Ni/Cr outlier microtektites (∼15% in total) deviate from the above mixing trend, perhaps resulting from incomplete homogenization of heterogeneous impactor and target precursor materials at the microtektite scale, respectively. Together with previous evidence from the ∼35 Myr old Popigai impact spherules and the ∼1 Myr old Ivory Coast microtektites, our finding suggests that at least three of the five known Cenozoic distal impact ejecta were generated by the impacts of large stony asteroids of chondritic composition, and possibly of ordinary chondritic composition. The impactor signature found in Australasian microtektites documents mixing of target and impactor melts upon impact cratering. This requires target-impactor mixing in both the two competing models in literature for the formation of the Australasian tektites/microtektites: the impact cratering and low-altitude airburst plume models.

Risk-adjusted Outcomes of Clinically Relevant Pancreatic Fistula Following Pancreatoduodenectomy: A Model for Performance Evaluation.

PubMed

McMillan, Matthew T; Soi, Sameer; Asbun, Horacio J; Ball, Chad G; Bassi, Claudio; Beane, Joal D; Behrman, Stephen W; Berger, Adam C; Bloomston, Mark; Callery, Mark P; Christein, John D; Dixon, Elijah; Drebin, Jeffrey A; Castillo, Carlos Fernandez-Del; Fisher, William E; Fong, Zhi Ven; House, Michael G; Hughes, Steven J; Kent, Tara S; Kunstman, John W; Malleo, Giuseppe; Miller, Benjamin C; Salem, Ronald R; Soares, Kevin; Valero, Vicente; Wolfgang, Christopher L; Vollmer, Charles M

2016-08-01

To evaluate surgical performance in pancreatoduodenectomy using clinically relevant postoperative pancreatic fistula (CR-POPF) occurrence as a quality indicator. Accurate assessment of surgeon and institutional performance requires (1) standardized definitions for the outcome of interest and (2) a comprehensive risk-adjustment process to control for differences in patient risk. This multinational, retrospective study of 4301 pancreatoduodenectomies involved 55 surgeons at 15 institutions. Risk for CR-POPF was assessed using the previously validated Fistula Risk Score, and pancreatic fistulas were stratified by International Study Group criteria. CR-POPF variability was evaluated and hierarchical regression analysis assessed individual surgeon and institutional performance. There was considerable variability in both CR-POPF risk and occurrence. Factors increasing the risk for CR-POPF development included increasing Fistula Risk Score (odds ratio 1.49 per point, P < 0.00001) and octreotide (odds ratio 3.30, P < 0.00001). When adjusting for risk, performance outliers were identified at the surgeon and institutional levels. Of the top 10 surgeons (≥15 cases) for nonrisk-adjusted performance, only 6 remained in this high-performing category following risk adjustment. This analysis of pancreatic fistulas following pancreatoduodenectomy demonstrates considerable variability in both the risk and occurrence of CR-POPF among surgeons and institutions. Disparities in patient risk between providers reinforce the need for comprehensive, risk-adjusted modeling when assessing performance based on procedure-specific complications. Furthermore, beyond inherent patient risk factors, surgical decision-making influences fistula outcomes.

Urinary YKL-40 as a Candidate Biomarker for Febrile Urinary Tract Infection in Young Children.

PubMed

Kim, Hyun Hee; Chung, Mi Hae; Bin, Joong Hyun; Cho, Kyoung Soon; Lee, Juyoung; Suh, Jin Soon

2018-01-01

Given that YKL-40 is a known marker of inflammation, we sought to determine its association with urinary tract infection (UTI) in febrile children. In total, 44 children aged 0 to 24 months with febrile UTI and 35 age- and sex-matched controls with fever from other causes were enrolled in the study. ELISA was performed to determine the level of YKL-40 in urine collected from each child. The ratio of urinary YKL-40 to creatinine (Cr) was higher in the children with a UTI than in the controls (P<0.001). The area under the ROC curve for detecting UTI was 0.88 for the urinary YKL-40/Cr ratio, 0.86 for pyuria, and 0.71 for positive nitrite on urinalysis. We applied a cut-off value of 125.23 pg/mg to urinary YKL-40/Cr for detecting UTI. Eight of nine children in the control group with pyuria had urinary YKL-40/Cr levels lower than 125.23 pg/mg, and the one child in the UTI group without pyuria or positive nitrite had a urinary YKL-40/Cr level greater than 125.23 pg/mg. Determining the levels of urinary YKL-40/Cr may help identify true cases of UTI in febrile young children, especially when they have pyuria but not nitrite, or have neither pyuria nor nitrite in the urine. © The Korean Society for Laboratory Medicine

Urinary YKL-40 as a Candidate Biomarker for Febrile Urinary Tract Infection in Young Children

PubMed Central

Kim, Hyun Hee; Chung, Mi Hae; Bin, Joong Hyun; Cho, Kyoung Soon; Lee, Juyoung

2018-01-01

Background Given that YKL-40 is a known marker of inflammation, we sought to determine its association with urinary tract infection (UTI) in febrile children. Methods In total, 44 children aged 0 to 24 months with febrile UTI and 35 age- and sex-matched controls with fever from other causes were enrolled in the study. ELISA was performed to determine the level of YKL-40 in urine collected from each child. Results The ratio of urinary YKL-40 to creatinine (Cr) was higher in the children with a UTI than in the controls (P<0.001). The area under the ROC curve for detecting UTI was 0.88 for the urinary YKL-40/Cr ratio, 0.86 for pyuria, and 0.71 for positive nitrite on urinalysis. We applied a cut-off value of 125.23 pg/mg to urinary YKL-40/Cr for detecting UTI. Eight of nine children in the control group with pyuria had urinary YKL-40/Cr levels lower than 125.23 pg/mg, and the one child in the UTI group without pyuria or positive nitrite had a urinary YKL-40/Cr level greater than 125.23 pg/mg. Conclusions Determining the levels of urinary YKL-40/Cr may help identify true cases of UTI in febrile young children, especially when they have pyuria but not nitrite, or have neither pyuria nor nitrite in the urine. PMID:29071817

The bonding, charge distribution, spin ordering, optical, and elastic properties of four MAX phases Cr2AX (A = Al or Ge, X = C or N): From density functional theory study

NASA Astrophysics Data System (ADS)

Li, Neng; Mo, Yuxiang; Ching, Wai-Yim

2013-11-01

In this work, we assess a full spectrum of properties (chemical bonding, charge distribution, spin ordering, optical, and elastic properties) of Cr2AC (A = Al, Ge) and their hypothetical nitride counterparts Cr2AN (A = Al, Ge) based on density functional theory calculations. The calculated total energy values indicate that a variety of spin ordering of these four compounds depending on interlayer-interactions between M-A and M-X within the sublattice, which is supported by bonding analysis. MAX phase materials are discovered to possess exotic magnetic properties which indicates that these materials could serve as promising candidates for novel layered magnetic materials for various electronic and spintronic applications. Further analysis of optical properties for two polarization vectors of Cr2AX shows that the reflectivity is high in the visible-ultraviolet region up to ˜15 eV suggesting Cr2AX as a promising candidate for use as a coating material. The elastic coefficients (Cij) and bulk mechanical properties [bulk modulus (K), shear modulus (G), Young's modulus (E), Poisson's ratio (η), and Pugh ratio (G/K)] of these four Cr2AX compounds are also calculated and analyzed, which pave the way to predict or design new MAX phases that are less brittle or tougher by having a lower G/K value or higher η.

CX3CR1-dependent recruitment of mature NK cells into the central nervous system contributes to control autoimmune neuroinflammation.

PubMed

Hertwig, Laura; Hamann, Isabell; Romero-Suarez, Silvina; Millward, Jason M; Pietrek, Rebekka; Chanvillard, Coralie; Stuis, Hanna; Pollok, Karolin; Ransohoff, Richard M; Cardona, Astrid E; Infante-Duarte, Carmen

2016-08-01

Fractalkine receptor (CX3CR1)-deficient mice develop very severe experimental autoimmune encephalomyelitis (EAE), associated with impaired NK cell recruitment into the CNS. Yet, the precise implications of NK cells in autoimmune neuroinflammation remain elusive. Here, we investigated the pattern of NK cell mobilization and the contribution of CX3CR1 to NK cell dynamics in the EAE. We show that in both wild-type and CX3CR1-deficient EAE mice, NK cells are mobilized from the periphery and accumulate in the inflamed CNS. However, in CX3CR1-deficient mice, the infiltrated NK cells displayed an immature phenotype contrasting with the mature infiltrates in WT mice. This shift in the immature/mature CNS ratio contributes to EAE exacerbation in CX3CR1-deficient mice, since transfer of mature WT NK cells prior to immunization exerted a protective effect and normalized the CNS NK cell ratio. Moreover, mature CD11b(+) NK cells show higher degranulation in the presence of autoreactive 2D2 transgenic CD4(+) T cells and kill these autoreactive cells more efficiently than the immature CD11b(-) fraction. Together, these data suggest a protective role of mature NK cells in EAE, possibly through direct modulation of T cells inside the CNS, and demonstrate that mature and immature NK cells are recruited into the CNS by distinct chemotactic signals. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bioavailability of Carbohydrate Content in Natural and Transgenic Switchgrasses for the Extreme Thermophile Caldicellulosiruptor bescii

PubMed Central

Zurawski, Jeffrey V.; Khatibi, Piyum A.; Akinosho, Hannah O.; Straub, Christopher T.; Compton, Scott H.; Conway, Jonathan M.; Lee, Laura L.; Ragauskas, Arthur J.; Davison, Brian H.; Adams, Michael W. W.

2017-01-01

ABSTRACT Improving access to the carbohydrate content of lignocellulose is key to reducing recalcitrance for microbial deconstruction and conversion to fuels and chemicals. Caldicellulosiruptor bescii completely solubilizes naked microcrystalline cellulose, yet this transformation is impeded within the context of the plant cell wall by a network of lignin and hemicellulose. Here, the bioavailability of carbohydrates to C. bescii at 70°C was examined for reduced lignin transgenic switchgrass lines COMT3(+) and MYB Trans, their corresponding parental lines (cultivar Alamo) COMT3(−) and MYB wild type (WT), and the natural variant cultivar Cave-in-Rock (CR). Transgenic modification improved carbohydrate solubilization by C. bescii to 15% (2.3-fold) for MYB and to 36% (1.5-fold) for COMT, comparable to the levels achieved for the natural variant, CR (36%). Carbohydrate solubilization was nearly doubled after two consecutive microbial fermentations compared to one microbial step, but it never exceeded 50% overall. Hydrothermal treatment (180°C) prior to microbial steps improved solubilization 3.7-fold for the most recalcitrant line (MYB WT) and increased carbohydrate recovery to nearly 50% for the least recalcitrant lines [COMT3(+) and CR]. Alternating microbial and hydrothermal steps (T→M→T→M) further increased bioavailability, achieving carbohydrate solubilization ranging from 50% for MYB WT to above 70% for COMT3(+) and CR. Incomplete carbohydrate solubilization suggests that cellulose in the highly lignified residue was inaccessible; indeed, residue from the T→M→T→M treatment was primarily glucan and inert materials (lignin and ash). While C. bescii could significantly solubilize the transgenic switchgrass lines and natural variant tested here, additional or alternative strategies (physical, chemical, enzymatic, and/or genetic) are needed to eliminate recalcitrance. IMPORTANCE Key to a microbial process for solubilization of plant biomass is the organism's access to the carbohydrate content of lignocellulose. Economically viable routes will characteristically minimize physical, chemical, and biological pretreatment such that microbial steps contribute to the greatest extent possible. Recently, transgenic versions of plants and trees have been developed with the intention of lowering the barrier to lignocellulose conversion, with particular focus on lignin content and composition. Here, the extremely thermophilic bacterium Caldicellulosiruptor bescii was used to solubilize natural and genetically modified switchgrass lines, with and without the aid of hydrothermal treatment. For lignocellulose conversion, it is clear that the microorganism, plant biomass substrate, and processing steps must all be considered simultaneously to achieve optimal results. Whether switchgrass lines engineered for low lignin or natural variants with desirable properties are used, conversion will depend on microbial access to crystalline cellulose in the plant cell wall. PMID:28625990

Proton Magnetic Resonance Spectroscopy in Social Anxiety Disorder.

PubMed

Tükel, Raşit; Aydın, Kubilay; Yüksel, Çağrı; Ertekin, Erhan; Koyuncu, Ahmet

2016-01-01

In the present study, 24 nonmedicated patients with social anxiety disorder (SAD) were compared with 24 healthy control subjects to assess metabolite levels in the anterior cingulate, insula, caudate, and putamen using proton magnetic resonance spectroscopy. The ratio of N-acetylaspartate (NAA)/creatine (Cr) was significantly higher in patients with SAD than in healthy control subjects in the anterior cingulate and insula. NAA/Cr ratios in the insula correlated positively with the Liebowitz Social Anxiety Scale total scores in patients with SAD. Our results support the significance and biochemical involvement of the anterior cingulate and insula in the pathophysiology of SAD.

Spin dependent transport properties of Mn-Ga/MgO/Mn-Ga magnetic tunnel junctions with metal(Mg, Co, Cr) insertion layer

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

Liang, S. H.; Tao, L. L.; Liu, D. P., E-mail: dpliu@iphy.ac.cn

We report a first principles theoretical investigation of spin polarized quantum transport in Mn{sub 2}Ga/MgO/Mn{sub 2}Ga and Mn{sub 3}Ga/MgO/Mn{sub 3}Ga magnetic tunneling junctions (MTJs) with the consideration of metal(Mg, Co, Cr) insertion layer effect. By changing the concentration of Mn, our calculation shows a considerable disparity in transport properties: A tunneling magnetoresistance (TMR) ratio of 852% was obtained for Mn{sub 2}Ga-based MTJs, however, only a 5% TMR ratio for Mn{sub 3}Ga-based MTJs. In addition, the influence of insertion layer has been considered in our calculation. We found the Co insertion layer can increase the TMR of Mn{sub 2}Ga-based MTJ tomore » 904%; however, the Cr insertion layer can decrease the TMR by 668%; A negative TMR ratio can be obtained with Mg insertion layer. Our work gives a comprehensive understanding of the influence of different insertion layer in Mn-Ga based MTJs. It is proved that, due to the transmission can be modulated by the interfacial electronic structure of insertion, the magnetoresistance ratio of Mn{sub 2}Ga/MgO/Mn{sub 2}Ga MTJ can be improved by inserting Co layer.« less

Effects of smelting parameters on the slag/metal separation behaviors of Hongge vanadium-bearing titanomagnetite metallized pellets obtained from the gas-based direct reduction process

NASA Astrophysics Data System (ADS)

Feng, Cong; Chu, Man-sheng; Tang, Jue; Liu, Zheng-gen

2018-06-01

Smelting separations of Hongge vanadium-bearing titanomagnetite metallized pellets (HVTMP) prepared by gas-based direct reduction were investigated, and the effects of smelting parameters on the slag/metal separation behaviors were analyzed. Relevant mechanisms were elucidated using X-ray diffraction analysis, FACTSAGE 7.0 calculations, and scanning electron microscopy observations. The results show that, when the smelting temperature, time, and C/O ratio are increased, the recoveries of V and Cr of HVTMP in pig iron are improved, the recovery of Fe initially increases and subsequently decreases, and the recovery of TiO2 in slag decreases. When the smelting CaO/SiO2 ratio is increased, the recoveries of Fe, V, and Cr in pig iron increase and the recovery of TiO2 in slag initially increases and subsequently decreases. The appropriate smelting separation parameters for HVTMP are as follows: smelting temperature of 1873 K; smelting time of 30-50 min; C/O ratio of 1.25; and CaO/SiO2 ratio of 0.50. With these optimized parameters (smelting time: 30 min), the recoveries of Fe, V, Cr, and TiO2 are 99.5%, 91.24%, 92.41%, and 94.86%, respectively.

Very large cooperative effects in heterobimetallic titanium-chromium catalysts for ethylene polymerization/copolymerization.

PubMed

Liu, Shaofeng; Motta, Alessandro; Mouat, Aidan R; Delferro, Massimiliano; Marks, Tobin J

2014-07-23

The heterobimetallic complexes, (η(5)-indenyl)[1-Me2Si((t)BuN)TiCl2]-3-CnH2n-[N,N-bis(2-(ethylthio)ethyl)amine]CrCl3 (n = 0, Ti-C0-Cr(SNS); n = 2, Ti-C2-Cr(SNS); n = 6, Ti-C6-Cr(SNS)), (η(5)-indenyl)[1-Me2Si((t)BuN)TiCl2]-3-C2H4-[N,N-bis((o-OMe-C6H4)2P)amine]CrCl3 (Ti-C2-Cr(PNP)), and (η(5)-indenyl)[1-Me2Si((t)BuN)TiCl2]-3-C2H4-[N,N-bis((diethylamine)ethyl)-amine]CrCl3 (Ti-C2-Cr(NNN)), are synthesized, fully characterized, and employed as olefin polymerization catalysts. With ethylene as the feed and MAO as cocatalyst/activator, SNS-based complexes Ti-C0-Cr(SNS), Ti-C2-Cr(SNS), and Ti-C6-Cr(SNS) afford linear low-density polyethylenes (LLDPEs) with exclusive n-butyl branches (6.8-25.8 branches/1000 C), while under identical polymerization conditions Ti-C2-Cr(PNP) and Ti-C2-Cr(NNN) produce polyethylenes with heterogeneous branching (C2, C4, and C≥6) or negligible branching, respectively. Under identical ethylene polymerization conditions, Ti-C0-Cr(SNS) produces polyethylenes with higher activity (4.5× and 6.1×, respectively), Mn (1.3× and 1.8×, respectively), and branch density (1.4× and 3.8×, respectively), than Ti-C2-Cr(SNS) and Ti-C6-Cr(SNS). Versus a CGC(Et)Ti + SNSCr tandem catalyst, Ti-C0-Cr(SNS) yields polyethylene with somewhat lower activity, but with 22.6× higher Mn and 4.0× greater branching density under identical conditions. In ethylene +1-pentene competition experiments, Ti-C0-Cr(SNS) yields 5.5% n-propyl branches and 94.5% n-butyl branches at [1-pentene] = 0.1 M, and the estimated effective local concentration of 1-hexene is ∼8.6 M. In contrast, the tandem CGC(Et)Ti + SNSCr system yields 91.0% n-propyl branches under identical reaction conditions. The homopolymerization and 1-pentene competition results argue that close Ti···Cr spatial proximity together with weak C-H···Ti and C-H···S interactions significantly influence relative 1-hexene enchainment and chain transfer rates, supported by DFT computation, and that such effects are conversion insensitive but cocatalyst and solvent sensitive.

CXCR3/CCR5 pathways in metastatic melanoma patients treated with adoptive therapy and interleukin-2

PubMed Central

Bedognetti, D; Spivey, T L; Zhao, Y; Uccellini, L; Tomei, S; Dudley, M E; Ascierto, M L; De Giorgi, V; Liu, Q; Delogu, L G; Sommariva, M; Sertoli, M R; Simon, R; Wang, E; Rosenberg, S A; Marincola, F M

2013-01-01

Background: Adoptive therapy with tumour-infiltrating lymphocytes (TILs) induces durable complete responses (CR) in ∼20% of patients with metastatic melanoma. The recruitment of T cells through CXCR3/CCR5 chemokine ligands is critical for immune-mediated rejection. We postulated that polymorphisms and/or expression of CXCR3/CCR5 in TILs and the expression of their ligands in tumour influence the migration of TILs to tumours and tumour regression. Methods: Tumour-infiltrating lymphocytes from 142 metastatic melanoma patients enrolled in adoptive therapy trials were genotyped for CXCR3 rs2280964 and CCR5-Δ32 deletion, which encodes a protein not expressed on the cell surface. Expression of CXCR3/CCR5 in TILs and CXCR3/CCR5 and ligand genes in 113 available parental tumours was also assessed. Tumour-infiltrating lymphocyte data were validated by flow cytometry (N=50). Results: The full gene expression/polymorphism model, which includes CXCR3 and CCR5 expression data, CCR5-Δ32 polymorphism data and their interaction, was significantly associated with both CR and overall response (OR; P=0.0009, and P=0.007, respectively). More in detail, the predicted underexpression of both CXCR3 and CCR5 according to gene expression and polymorphism data (protein prediction model, PPM) was associated with response to therapy (odds ratio=6.16 and 2.32, for CR and OR, respectively). Flow cytometric analysis confirmed the PPM. Coordinate upregulation of CXCL9, CXCL10, CXCL11, and CCL5 in pretreatment tumour biopsies was associated with OR. Conclusion: Coordinate overexpression of CXCL9, CXCL10, CXCL11, and CCL5 in pretreatment tumours was associated with responsiveness to treatment. Conversely, CCR5-Δ32 polymorphism and CXCR3/CCR5 underexpression influence downregulation of the corresponding receptors in TILs and were associated with likelihood and degree of response. PMID:24129241

Adsorption isotherm studies of chromium (VI) from aqueous solutions using sol-gel hydrotalcite-like compounds.

PubMed

Ramos-Ramírez, Esthela; Ortega, Norma L Gutiérrez; Soto, Cesar A Contreras; Gutiérrez, Maria T Olguín

2009-12-30

In under-developed countries, industries such as paint and pigment manufacturing, leather tanning, chrome plating and textile processing, usually discharge effluents containing Cr(VI) and Cr(III) into municipal sanitary sewers. It has been reported that Cr(VI) acts as a powerful epithelial irritant and as a human carcinogen. In the present work, hydrotalcite-like compounds with a Mg/Al ratio=2 were synthesized by the sol-gel method. The hydrotalcite-like compounds and their corresponding thermally treated products were characterized by powder X-ray diffraction, infrared spectroscopy and N(2) adsorption. The hydrotalcite-like compounds and the heated solids were used as adsorbents for Cr(VI) in aqueous solutions. Adsorption isotherm studies of Cr(VI) from aqueous solution are described. The adsorbent capacity was determined using the Langmuir, Freundlich and Dubinin-Radushkevich adsorption isotherm models. The Cr(VI) adsorption isotherm data fit best to the Langmuir isotherm model. The maximum Cr(VI) uptake by hydrotalcite and the heated solids was determined using the Langmuir equation and was found to range between 26 and 29 mg Cr(VI)/g adsorbent.

Effects of heavy metals (Fe3+/Cr6+) on low-level energy generation in a microbial fuel cell

NASA Astrophysics Data System (ADS)

Caparanga, A. R.; Balatbat, A. S.; Tayo, L.

2017-06-01

A dual-chamber microbial fuel cell (MFC) was constructed with Pseudomonas aeruginosa as biocatalyst to facilitate substrate conversion and, consequently, low-level energy generation. To simulate a wastewater situation with BOD and heavy metals contamination, glucose and Fe3+ and Cr6+ were used as substrate and heavy-metal spikes, respectively. The effects of varying substrate concentrations (150 ppm, 300 ppm, 600 ppm) and heavy metal loads (10 ppm, 50 ppm, 100 ppm) on overall power generation were evaluated. The presence of Cr6+ in the anode compartment decreased the potential from 565 to 201 mV (i.e., lowest value achieved at highest Cr6+ concentration of 300 ppm). On the other hand, replacing Cr6+ with Fe3+ as electron acceptor resulted in substantial increase in measured potential (i.e., from 565 to 703 mV). Increasing glucose concentrations resulted in longer time to reach constant open circuit voltage. A maximum potential of 606 mV was achieved at 1200 ppm glucose. Incorporating Pseudomonas aeruginosa increased the potential from 256 to 592 mV. On the basis of these results, a microbial fuel cell feeding on wastewater can be an important potential technology for generating low-level energy

One step bioconversion of waste precious metals into Serratia biofilm-immobilized catalyst for Cr(VI) reduction.

PubMed

Yong, P; Liu, W; Zhang, Z; Beauregard, D; Johns, M L; Macaskie, L E

2015-11-01

For reduction of Cr(VI) the Pd-catalyst is excellent but costly. The objectives were to prove the robustness of a Serratia biofilm as a support for biogenic Pd-nanoparticles and to fabricate effective catalyst from precious metal waste. Nanoparticles (NPs) of palladium were immobilized on polyurethane reticulated foam and polypropylene supports via adhesive biofilm of a Serratia sp. The biofilm adhesion and cohesion strength were unaffected by palladization and catalytic biofilm integrity was also shown by magnetic resonance imaging. Biofilm-Pd and mixed precious metals on biofilm (biofilm-PM) reduced 5 mM Cr(VI) to Cr(III) when immobilized in a flow-through column reactor, at respective flow rates of 9 and 6 ml/h. The lower activity of the latter was attributed to fewer, larger, metal deposits on the bacteria. Activity was lost in each case at pH 7 but was restored by washing with 5 mM citrate solution or by exposure of columns to solution at pH 2, suggesting fouling by Cr(III) hydroxide product at neutral pH. A 'one pot' conversion of precious metal waste into new catalyst for waste decontamination was shown in a continuous flow system based on the use of Serratia biofilm to manufacture and support catalytic Pd-nanoparticles.

Clinopyroxenite dykes within a banded unit in the basal mantle section of the northern part of the Oman ophiolite: A record of the latest deep-seated magmatism

NASA Astrophysics Data System (ADS)

Ishimaru, Satoko; Arai, Shoji; Tamura, Akihiro

2017-11-01

We found clinopyroxenite dykes in a banded harzburgite block within the Sumeini area in the uppermost part of the metamorphic sole of the northern part of the Oman ophiolite. The dykes clearly cut the deformational structure of the harzburgite and contain its fragments, indicating dyke formation during obduction of the ophiolite. The Mg# [= Mg / (Mg + total Fe)] of clinopyroxenes in the dykes ranges from 0.81 to 0.91, and increases up to 0.93 proximal to harzburgite fragments. Mantle minerals in the harzburgite fragments were modified chemically through interaction with the magma that formed the dyke, yielding lower clinopyroxene and spinel Mg#, and spinels with higher TiO2 contents than those in the unaltered harzburgite. These geochemical features indicate that the clinopyroxenite dykes are cumulates derived from a relatively deep-seated primitive magma enriched in light rare earth elements (LREE) with an ocean island basalt (OIB)-like affinity, geochemically similar to the V3 lavas of an off-ridge origin. Combining these data with geological observations suggests that the clinopyroxenite dykes represent root system of the V3 lavas. Our analyses of the clinopyroxenite dykes testify to the external nature of the V3 magmas, which was added to the sliced oceanic lithosphere from the outside. It is likely that the V3 magma underwent deep-seated crystallization of clinopyroxene and had limited interaction with mantle peridotite en route to the surface. The mode of occurrence of the Sumeini clinopyroxenites (i.e., emplaced into a banded harzburgite block surrounded by garnet amphibolite) is consistent with the generation of OIB-like magmas (V3 lava) beneath the Oman ophiolite resulting from the break-off of the "subducting slab" and subsequent infiltration of hot asthenospheric mantle. This view is consistent with the limited distribution of V3-related rocks in the Oman ophiolite. The production of such OIB-like magmas during ophiolite obduction is not a rare event, especially during the subduction of young and hot oceanic lithosphere. Footnote: Mg#, Mg/(Mg + Fe total) atomic ratio; Cr#, Cr/(Cr + Al) atomic ratio; YAl, Al/(Al + Cr + Fe3 +) atomic ratio; YCr, Al/(Al + Cr + Fe3 +) atomic ratio; YFe, Al/(Al + Cr + Fe3 +) atomic ratio. RSD: relative standard deviation. Ref. values: Reference values of JEOL_Kfs from a JEOL database.

Prediction of Cortical Defect Using C-Reactive Protein and Urine Sodium to Potassium Ratio in Infants with Febrile Urinary Tract Infection

PubMed Central

Jung, Su Jin

2016-01-01

Purpose We investigated whether C-reactive protein (CRP) levels, urine protein-creatinine ratio (uProt/Cr), and urine electrolytes can be useful for discriminating acute pyelonephritis (APN) from other febrile illnesses or the presence of a cortical defect on 99mTc dimercaptosuccinic acid (DMSA) scanning (true APN) from its absence in infants with febrile urinary tract infection (UTI). Materials and Methods We examined 150 infants experiencing their first febrile UTI and 100 controls with other febrile illnesses consecutively admitted to our hospital from January 2010 to December 2012. Blood (CRP, electrolytes, Cr) and urine tests [uProt/Cr, electrolytes, and sodium-potassium ratio (uNa/K)] were performed upon admission. All infants with UTI underwent DMSA scans during admission. All data were compared between infants with UTI and controls and between infants with or without a cortical defect on DMSA scans. Using multiple logistic regression analysis, the ability of the parameters to predict true APN was analyzed. Results CRP levels and uProt/Cr were significantly higher in infants with true APN than in controls. uNa levels and uNa/K were significantly lower in infants with true APN than in controls. CRP levels and uNa/K were relevant factors for predicting true APN. The method using CRP levels, u-Prot/Cr, u-Na levels, and uNa/K had a sensitivity of 94%, specificity of 65%, positive predictive value of 60%, and negative predictive value of 95% for predicting true APN. Conclusion We conclude that these parameters are useful for discriminating APN from other febrile illnesses or discriminating true APN in infants with febrile UTI. PMID:26632389

Metabolic and Structural Imaging at 7 Tesla After Repetitive Mild Traumatic Brain Injury in Immature Rats.

PubMed

Fidan, Emin; Foley, Lesley M; New, Lee Ann; Alexander, Henry; Kochanek, Patrick M; Hitchens, T Kevin; Bayır, Hülya

2018-01-01

Mild traumatic brain injury (mTBI) in children is a common and serious public health problem. Traditional neuroimaging findings in children who sustain mTBI are often normal, putting them at risk for repeated mTBI (rmTBI). There is a need for more sensitive imaging techniques capable of detecting subtle neurophysiological alterations after injury. We examined neurochemical and white matter changes using diffusion tensor imaging of the whole brain and proton magnetic resonance spectroscopy of the hippocampi at 7 Tesla in 18-day-old male rats at 7 days after mTBI and rmTBI. Traumatic axonal injury was assessed by beta-amyloid precursor protein accumulation using immunohistochemistry. A significant decrease in fractional anisotropy and increase in axial and radial diffusivity were observed in several brain regions, especially in white matter regions, after a single mTBI versus sham and more prominently after rmTBI. In addition, we observed accumulation of beta-amyloid precursor protein in the external capsule after mTBI and rmTBI. mTBI and rmTBI reduced the N-acetylaspartate/creatine ratio (NAA/Cr) and increased the myoinositol/creatine ratio (Ins/Cr) versus sham. rmTBI exacerbated the reduction in NAA/Cr versus mTBI. The choline/creatine (Cho/Cr) and (lipid/Macro Molecule 1)/creatine (Lip/Cr) ratios were also decreased after rmTBI versus sham. Diffusion tensor imaging findings along with the decrease in Cho and Lip after rmTBI may reflect damage to axonal membrane. NAA and Ins are altered at 7 days after mTBI and rmTBI likely reflecting neuro-axonal damage and glial response, respectively. These findings may be relevant to understanding the extent of disability following mTBI and rmTBI in the immature brain and may identify possible therapeutic targets.

Decreases in Short Term Memory, IQ, and Altered Brain Metabolic Ratios in Urban Apolipoprotein ε4 Children Exposed to Air Pollution.

PubMed

Calderón-Garcidueñas, Lilian; Mora-Tiscareño, Antonieta; Franco-Lira, Maricela; Zhu, Hongtu; Lu, Zhaohua; Solorio, Edelmira; Torres-Jardón, Ricardo; D'Angiulli, Amedeo

2015-01-01

Children's urban air pollution exposures result in systemic and brain inflammation and the early hallmarks of Alzheimer's disease (AD). The apolipoprotein E (APOE) ε4 allele is the most prevalent genetic risk for AD. We assessed whether APOE in healthy children modulates cognition, olfaction, and metabolic brain indices. The Wechsler Intelligence Scale for Children (WISC-R) and the University of Pennsylvania Smell Identification Test were administered to 50 Mexico City Metropolitan Area children (13.4 ± 4.8 years, 28 APOE ε3 and 22 APOE ε4). N-acetylaspartate (NAA)/creatine (Cr), choline (Cho)/Cr, myo-inositol (mI)/Cr, and NAA/mI were calculated using proton magnetic resonance spectroscopy in the white matter of the frontal and parietal lobes, hippocampus, and pons. APOE ε4 versus ε3 children had a reduced NAA/Cr ratio in the right frontal white matter and decrements on attention, short-term memory, and below-average scores in Verbal and Full Scale IQ (>10 points). APOE modulated the group effects between WISC-R and left frontal and parietal white matter, and hippocampus metabolites. Soap was the predominantly failed odor in urban children and, in APOE ε4 versus ε3 carriers, strongly correlated with left hippocampus mI/Cr ratio. APOE modulates responses to air pollution in the developing brain. APOE ε4 carriers could have a higher risk of developing early AD if they reside in a polluted environment. APOE, cognition, and olfaction testing and targeted magnetic resonance spectroscopy may contribute to the assessment of urban children and their results could provide new paths toward the unprecedented opportunity for early neuroprotection and AD prevention.

A factor influence study of trace element bioaccumulation in moss bags.

PubMed

Cesa, M; Campisi, B; Bizzotto, A; Ferraro, C; Fumagalli, F; Nimis, P L

2008-10-01

Moss bags of Rhynchostegium riparioides were exposed to different water concentrations of 11 trace elements under laboratory conditions, according to a saturated fractional factorial design (67 treated combinations), with the aim of measuring (1) element uptake and (2) the main effects and first-order interactions of influent factors. Bioaccumulation was directly proportional to water concentration, but the uptake ratio (ranging from 10(2) to 10(5)) also depended on the concentration of other metals. The highest uptake ratios were observed for Al, Cu, Cr, Hg, and Pb. The multiple regression model showed that interactions among elements exist and induce both antagonism (Fe is the most frequent competitor) and synergism (Cr exerts a great influence on Pb and Zn uptake). Interactions might be relatively strong (as for As, Cr, and Pb) or weak (Cd and Hg). This evidence should be taken into consideration in biomonitoring surveys of industrial sites, where effluents release more than one contaminant.

Using metal ratios to detect emissions from municipal waste incinerators in ambient air pollution data

NASA Astrophysics Data System (ADS)

Font, Anna; de Hoogh, Kees; Leal-Sanchez, Maria; Ashworth, Danielle C.; Brown, Richard J. C.; Hansell, Anna L.; Fuller, Gary W.

2015-07-01

This study aimed to fingerprint emissions from six municipal waste incinerators (MWIs) and then test if these fingerprint ratios could be found in ambient air samples. Stack emissions tests from MWIs comprised As, Cd, Cr, Cu, Pb, Mn, Ni, V and Hg. Those pairs of metals showing good correlation (R > 0.75) were taken as tracers of MWI emissions and ratios calculated: Cu/Pb; Cd/Pb; Cd/Cu and Cr/Pb. Emissions ratios from MWIs differed significantly from those in ambient rural locations and those close to traffic. In order to identify MWI emissions in ambient air two analysis tests were carried out. The first, aimed to explore if MWI emissions dominate the ambient concentrations. The mean ambient ratio of each of the four metal ratios were calculated for six ambient sampling sites within 10 km from a MWI under stable meteorological conditions when the wind blew from the direction of the incinerator. Under these meteorological conditions ambient Cd/Pb was within the range of MWI emissions at one location, two monitoring sites measured mean Cr/Pb ratios representative of the MWI emissions and the four sites measured values of Cu/Pb within the range of MWI emissions. No ambient measurements had mean Cd/Cu ratios within the MWI values. Even though MWI was not the main source determining the ambient metal ratios, possible occasional plume grounding might have occurred. The second test then examined possible plume grounding by identifying the periods when all metal ratios differed from rural and traffic values at the same time and were consistent with MWI emissions. Metal ratios consistent with MWI emissions were found in ambient air within 10 km of one MWI for about 0.2% of study period. Emissions consistent with a second MWI were similarly detected at two ambient measurement sites about 0.1% and 0.02% of the time. Where plume grounding was detected, the maximum annual mean particulate matter (PM) from the MWI was estimated to be 0.03 μg m-3 to 0.12 μg m-3; 2-3 orders of magnitude smaller than background ambient PM10 concentrations. Ambient concentrations of Cr increased by 1.6-3.0 times when MWI emissions were detected. From our analysis we found no evidence of incinerator emissions in ambient metal concentrations around four UK MWIs. The six UK MWIs studied contributed little to ambient PM10 concentrations.

Survey of pain specialists regarding conversion of high-dose intravenous to neuraxial opioids

PubMed Central

Gorlin, Andrew W; Rosenfeld, David M; Maloney, Jillian; Wie, Christopher S; McGarvey, Johnathan; Trentman, Terrence L

2016-01-01

The conversion of high-dose intravenous (IV) opioids to an equianalgesic epidural (EP) or intrathecal (IT) dose is a common clinical dilemma for which there is little evidence to guide practice. Expert opinion varies, though a 100 IV:10:EP:1 IT conversion ratio is commonly cited in the literature, especially for morphine. In this study, the authors surveyed 724 pain specialists to elucidate the ratios that respondents apply to convert high-dose IV morphine, hydromorphone, and fentanyl to both EP and IT routes. Eighty-three respondents completed the survey. Conversion ratios were calculated and entered into graphical scatter plots. The data suggest that there is wide variation in how pain specialists convert high-dose IV opioids to EP and IT routes. The 100 IV:10 EP:1 IT ratio was the most common answer of survey respondent, especially for morphine, though also for hydromorphone and fentanyl. Furthermore, more respondents applied a more aggressive conversion strategy for hydromorphone and fentanyl, likely reflecting less spinal selectivity of those opioids compared with morphine. The authors conclude that there is little consensus on this issue and suggest that in the absence of better data, a conservative approach to opioid conversion between IV and neuraxial routes is warranted. PMID:27703394

Increased Oxygenation of the Oceans Since the Mid-Cenozoic as Constrained by Cr/Co and Os/Ir Ratios in Oxic Pelagic Sediments

NASA Astrophysics Data System (ADS)

Hu, M.; Lee, C.

2005-12-01

In terms of redox, the marine sediments can be roughly divided into anoxic to suboxic sediments on the margins and oxic sediments in pelagic (open ocean) environments. The relative amounts of anoxic/suboxic sediments being deposited at any given time could be related to biological productivity and/or the efficiency of the ocean circulation system. How the depositional area of anoxic/suboxic deposition has changed through time is thus of concern. One way to track redox conditions is to investigate variations in the concentrations of redox sensitive trace metals. Most studies along these lines have focused on anoxic sediments. However, one problem with using anoxic sediments to study the global oceans is that such sediments are typically deposited in somewhat isolated basins, whose redox conditions may vary from basin to basin. An alternative approach, taken here, is to examine redox-sensitive elemental ratios in oxic pelagic sediments. This is motivated by the fact that pelagic sediments are more likely to reflect average ocean chemistry. In addition, the redox-sensitive metal contents of oxic sediments represent the complement to anoxic sediments. Choosing an appropriate redox-sensitive elemental ratio which eliminates dilution/concentration effects, requires the identification of trace metals that are preferentially precipitated in oxic conditions and those precipitated in more reducing conditions. Overall elemental behaviors were estimated by comparing hydrogenous or authigenic burial fluxes of various trace metals at given pelagic ODP sites to global riverine input fluxes. If the pelagic burial fluxes of a given element are significantly smaller than the riverine input flux, other burial outputs are implied, and it is hypothesized here that this element may precipitate in reducing conditions, such as in oceanic margin. If, on the other hand, the pelagic burial flux is equal to or greater than the riverine input flux, the implication is that oxic pelagic sediments must account for a significant proportion of the burial output of that element. In this case, we assume that this element is oxic-loving. Results of this work reveal that V, Cr, and Co may be particularly redox-sensitive: V and Cr precipitate in reducing environments while Co precipitates in more oxidizing environments. Results of our study, combined with existing data from the literature, show that Cr/Co ratios decrease with depth in DSDP596, 39, 801A, 319, 321, 465A, 577 in the N and S Pacific. After correcting for sedimentation rate, it is shown that the variation of Cr/Co versus time in all of these cores converge, which suggests that the variations in Cr/Co reflect a true variation in seawater composition. This also supported by the lack of sedimentation constrained by Cr/Co and Ce flux. Cr/Co remains low during the Cretaceous but begins to rise at ~25Ma across the entire Pacific. If the Cr/Co and Os/Ir ratio of inputs to the ocean have not changed much, this trend also matches that Os/Ir in the DSDP 596 site in the south Pacific. One interpretation of these results is that there has been a decrease in the area of anoxic/suboxic sedimentation beginning at this time. If correct, the implication is that there was a fundamental change in the redox conditions of the ocean in the mid-Cenozoic. We speculate that this might have been related to mid-Cenozoic global cooling, which may have increased the efficiency of the oceanic circulation system.

Memory is Not Enough: The Neurobiological Substrates of Dynamic Cognitive Reserve.

PubMed

Serra, Laura; Bruschini, Michela; Di Domenico, Carlotta; Gabrielli, Giulia Bechi; Marra, Camillo; Caltagirone, Carlo; Cercignani, Mara; Bozzali, Marco

2017-01-01

Changes in the residual memory variance are considered as a dynamic aspect of cognitive reserve (d-CR). We aimed to investigate for the first time the neural substrate associated with changes in the residual memory variance overtime in patients with amnestic mild cognitive impairment (aMCI). Thirty-four aMCI patients followed-up for 36 months and 48 healthy elderly individuals (HE) were recruited. All participants underwent 3T MRI, collecting T1-weighted images for voxel-based morphometry (VBM). They underwent an extensive neuropsychological battery, including six episodic memory tests. In patients and controls, factor analyses were used on the episodic memory scores to obtain a composite memory score (C-MS). Partial Least Square analyses were used to decompose the variance of C-MS in latent variables (LT scores), accounting for demographic variables and for the general cognitive efficiency level; linear regressions were applied on LT scores, striping off any contribution of general cognitive abilities, to obtain the residual value of memory variance, considered as an index of d-CR. LT scores and d-CR were used in discriminant analysis, in patients only. Finally, LT scores and d-CR were used as variable of interest in VBM analysis. The d-CR score was not able to correctly classify patients. In both aMCI patients and HE, LT1st and d-CR scores showed correlations with grey matter volumes in common and in specific brain areas. Using CR measures limited to assess memory function is likely less sensitive to detect the cognitive decline and predict the evolution of Alzheimer's disease. In conclusion, d-CR needs a measure of general cognition to identify conversion to Alzheimer's disease efficiently.

Unusual Oxidative Limitations for Al-MAX Phases

NASA Technical Reports Server (NTRS)

Smialek, James L.

2017-01-01

Alumina-forming MAX phases are well-known for their excellent oxidation resistance, rivaling many metallic NiAl, NiCrAl, and FeCrAl counterparts and with upper temperature capability possible to approximately1400C. However a number of limitations have been emerging that need to be acknowledged to permit robust performance in demanding applications. Ti2AlC and Ti3AlC2 possess excellent scale adhesion, cyclic oxidation/moisture/volatility resistance, and TBC compatibility. However they are very sensitive to Al content and flux in order to maintain an exclusive Al2O3 scale without runaway oxidation of ubiquitous TiO2 transient scales. Accelerated oxidation has been shown to occur for Al-depleted, damaged, or roughened surfaces at temperatures less than 1200C. Conversely, Cr2AlC is less sensitive to transients, but exhibits volatile losses at 1200C or above if common Cr7C3 impurity phases are present. Poor scale adhesion is exhibited after oxidation at 1150C or above, where spallation occurs at the Cr7C3 (depletion zone) interface. Delayed spallation is significant and suggests a moisture-induced phenomenon similar to non-adherent metallic systems. Re-oxidation of this surface does not reproduce the initial pure Al2O3 behavior, but initiates a less-protective scale. Cr2AlC has also been shown to have good long term bonding with superalloys at 800C, but exhibits significant Beta-NiAl + Cr7C3 diffusion zones at 1100C and above. This may set limits on Cr2AlC as a high temperature TBC bond coat on Ni-based superalloys, while improving corrosion resistance in lower temperature applications.

A model of the interfacial processes inhibiting the environmental degradation of Al-Cu alloys

NASA Astrophysics Data System (ADS)

Kearns, Jeffery Robert

A better understanding of the composition and structure of chemically treated Al alloy surfaces is necessary to devise new, more environmentally benign, coating systems for aircraft. In this work, the surface of AA2024-T3, as well as analogs for constituent intermetallic compounds (IMC), were examined at various stages of the Al alloy pretreatment and chromate conversion coating (CCC) process. A complement of techniques were used: imaging and dyanmic Secondary Ion Mass Spectroscopy (SIMS), Variable-Angle X-ray Photoelectron Spectroscopy (VA/XPS), Synchrotron Infrared Microspectroscopy (SIRS), X-ray Absorption Spectroscopy (XAS), and Electrochemical Impedance Spectroscopy (EIS). The water and hydrocarbons in commercial CCC destabilized Cr(VI) during exposure to soft x-rays. However, it was possible to prevent photochemical reduction with the ultra-clean vacuum pumping practice recently developed at Stony Brook. The type of pretreatment used prior to chromate conversion coating influenced the extent of IMC removal, Cu (re)distribution, and surface activity. Cu(I) was observed on all the chemically treated surfaces. Samples pretreated in Sanchem 1000 while galvanically coupled to a Pt mesh had a more desirable distribution of Cu for subsequent processing. Chromate reduction was not a significant factor in CCC aging over a 24-hr period, but surface dehydration and structural change were correlated and causative. Imaging SIMS revealed heterogeneities in the CCC that varied laterally with IMC in the alloy substrate. These regions were depleted in compounds containing Cr, F, and CN. Cu was found at localized sites in the CCC contact surface. Cyano groups were bound as Cr(IlI)-CNFe(H). The chromate available for CCC repair was located on matrix regions through the entire bulk of the CCC. The presence of residual contaminants (e.g. cleaning agents, metal working fluid, ink) affected the distribution of activator compounds (e.g. ferricyanide) in a CCC. The cyanide complex (Cr(Ill)-Fe-CN6) was found in the CCC bulk not just at the outermost surface. A new model for CCC on Al-Cr alloys is proposed. The model is based on the sol-gel-like nascent CCC that limits the transport of IMC dissolution products.

Efficacy and Safety of Neoadjuvant Treatment with Bevacizumab, Liposomal Doxorubicin, Cyclophosphamide and Paclitaxel Combination in Locally/Regionally Advanced, HER2-Negative, Grade III at Premenopausal Status Breast Cancer: A Phase II Study.

PubMed

Tampaki, Ekaterini C; Tampakis, Athanasios; Alifieris, Constantinos E; Krikelis, Dimitrios; Pazaiti, Anastasia; Kontos, Michalis; Trafalis, Dimitrios T

2018-05-09

In the era of personalized therapy, targeted treatment in specific patient populations is mandated. We evaluated the efficacy and safety of neoadjuvant treatment on locally advanced breast cancer (LABC) with a monoclonal agent against vascular endothelial growth factor (VEGF), bevacizumab plus chemotherapy combination of liposomal doxorubicin, cyclophosphamide and paclitaxel (PLAC-B). Patients enrolled were at premenopausal status and characterized by human epidermal growth factor receptor 2 (HER2)-negative, hormone-receptor positive (estrogen receptor/progesterone receptor-positive [ER/PR+]) or triple-negative (TNBC), LABC (T > 3 cm), with high-grade ductal carcinoma. Patients had to have a measurable disease and Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0, with adequate hematologic, renal, and hepatic function. Patients received intravenous liposomal doxorubicin 30 mg/m 2 , cyclophosphamide 600 mg/m 2 , paclitaxel 120 mg/m 2 , and bevacizumab 8 mg/kg on day 1 of 15-day cycles for four cycles (four administrations as neoadjuvant treatment). The primary endpoint was complete clinical (cCR) and pathologic (pCR) response rates, while secondary endpoints included safety, breast-conserving surgery (BCS) conversion rate, and disease-free survival (DFS). Sixty-two women were enrolled; 20 were ER/PR+ and 42 had TNBC. All underwent surgery, six received mastectomy, and 56 (90.3%) received BCS, with an equal conversion rate from initial indication for mastectomy. cCR was 25.8%. pCR in the breast and axilla occurred in 24 patients (38.7%). pCR was 42.9% for TNBC and 30% for ER/PR+. Hematologic adverse events (AEs) included neutropenia (74.2% total; 22.6% grade 3 [G3]) and febrile neutropenia (6.5% G3); non-hematologic G3 AEs included nausea (6.5%), mucositis (9.7%), and infection (3.2%), all of which were managed without negative sequelae. Over a 3-year follow-up, all patients were alive and DFS was 87.1%. PLAC-B as neoadjuvant treatment of this subpopulation with TNBC and ER/PR+ patients is effective and safe. Further studies are necessitated.

Using chromium stable isotope ratios to quantify Cr(VI) reduction: Lack of sorption effects

USGS Publications Warehouse

Ellis, A.S.; Johnson, T.M.; Bullen, T.D.

2004-01-01

Chromium stable isotope values can be effectively used to monitor reduction of Cr(VI) in natural waters. We investigate effects of sorption during transport of Cr(VI) which may also shift Cr isotopes values, complicating efforts to quantify reduction. This study shows that Cr stable isotope fractionation caused by sorption is negligible. Equilibrium fractionation of Cr stable isotopes between dissolved Cr-(VI) and Cr(VI) adsorbed onto ??-Al2O3 and goethite is less than 0.04???. (53Cr/52Cr) under environmentally relevant pH conditions. Batch experiments at pH 4.0 and pH 6.0 were conducted in series to sequentially magnify small isotope fractionations. A simple transport model suggests that adsorption may cause amplification of a small isotope fractionation along extreme fringes of a plume, leading to shifts in 53Cr/52Cr values. We therefore suggest that isotope values at extreme fringes of Cr plumes be critically evaluated for sorption effects. A kinetic effect was observed in experiments with goethite at pH 4 where apparently lighter isotopes diffuse into goethite clumps at a faster rate before eventually reaching equilibrium. This observed kinetic effect may be important in a natural system that has not attained equilibrium and is in need of further study. Cr isotope fractionation caused by speciation of Cr(VI) between HCrO4- and CrO42- was also examined, and we conclude that it is not measurable. In the absence of isotope fractionation caused by equilibrium speciation and sorption, most of the variation in ??53 Cr values may be attributed to reduction, and reliable estimates of Cr reduction can be made.

MR Spectroscopy to Distinguish between Supratentorial Intraventricular Subependymoma and Central Neurocytoma.

PubMed

Ueda, Fumiaki; Aburano, Hiroyuki; Ryu, Yasuji; Yoshie, Yuichi; Nakada, Mitsutoshi; Hayashi, Yutaka; Matsui, Osamu; Gabata, Toshifumi

2017-07-10

The purpose of this study was to discriminate supratentorial intraventricular subependymoma (SIS) from central neurocytoma (CNC) using magnetic resonance spectroscopy (MRS). Single-voxel proton MRS using a 1.5T or 3T MR scanner from five SISs, five CNCs, and normal controls were evaluated. They were examined using a point-resolved spectroscopy. Automatically calculated ratios comparing choline (Cho), N-acetylaspartate (NAA), myoinositol (MI), and/or glycine (Gly) to creatine (Cr) were determined. Evaluation of Cr to unsuppressed water (USW) was also performed. Mann-Whitney U test was carried out to test the significance of differences in the metabolite ratios. Detectability of lactate (Lac) and alanine (Ala) was evaluated. Although a statistically significant difference (P < 0.0001) was observed in Cho/Cr among SIS, control spectra, and CNC, no statistical difference was noted between SIS and control spectra (P = 0.11). Statistically significant differences were observed in NAA/Cr between SIS and CNC (P = 0.04) or control spectra (P < 0.0001). A statistically significant difference was observed in MI and/or Gly to Cr between SIS and control spectra (P = 0.03), and CNC and control spectra (P < 0.0006). There were no statistical differences between SIS and CNC for MI and/or Gly to Cr (P = 0.32). Significant statistical differences were found between SIS and control spectra (P < 0.0053), control spectra and CNC (P < 0.0016), and SIS and CNC (P < 0.0083) for Cr to USW. Lac inverted doublets were confirmed in two SISs. Triplets of Lac and Ala were detected in four spectra of CNC. The present study showed that MRS can be useful in discriminating SIS from CNC.

Fasting urinary calcium-to-creatinine and oxalate-to-creatinine ratios in dogs with calcium oxalate urolithiasis and breed-matched controls.

PubMed

Furrow, E; Patterson, E E; Armstrong, P J; Osborne, C A; Lulich, J P

2015-01-01

Hypercalciuria and hyperoxaluria are risk factors for calcium oxalate (CaOx) urolithiasis, but breed-specific reports of urinary metabolites and their relationship with stone status are lacking. To compare urinary metabolites (calcium and oxalate) and blood ionized calcium (iCa) concentrations between CaOx stone formers and breed-matched stone-free controls for the Miniature Schnauzer, Bichon Frise, and Shih Tzu breeds. Forty-seven Miniature Schnauzers (23 cases and 24 controls), 27 Bichons Frise (14 cases and 13 controls), and 15 Shih Tzus (7 cases and 8 controls). Prospective study. Fasting spot urinary calcium-to-creatinine and oxalate-to-creatinine ratios (UCa/Cr and UOx/Cr, respectively) and blood iCa concentrations were measured and compared between cases and controls within and across breeds. Regression models were used to test the effect of patient and environmental factors on these variables. UCa/Cr was higher in cases than controls for each of the 3 breeds. In addition to stone status, being on a therapeutic food designed to prevent CaOx stone recurrence was associated with higher UCa/Cr. UOx/Cr did not differ between cases and controls for any of the breeds. Blood iCa was higher in cases than controls in the Miniature Schnauzer and Bichon Frise breeds and had a moderate correlation with UCa/Cr. Hypercalciuria is associated with CaOx stone status in the Miniature Schnauzer, Bichon Frise, and Shih Tzu breeds. UOx/Cr did not correlate with stone status in these 3 breeds. These findings may influence breed-specific stone prevention recommendations. Copyright © 2015 by the American College of Veterinary Internal Medicine.

Analysis of spastic gait in cervical myelopathy: Linking compression ratio to spatiotemporal and pedobarographic parameters.

PubMed

Nagai, Taro; Takahashi, Yasuhito; Endo, Kenji; Ikegami, Ryo; Ueno, Ryuichi; Yamamoto, Kengo

2018-01-01

Gait dysfunction associated with spasticity and hyperreflexia is a primary symptom in patients with compression of cervical spinal cord. The objective of this study was to link maximum compression ratio (CR) to spatiotemporal/pedobarographic parameters. Quantitative gait analysis was performed by using a pedobarograph in 75 elderly males with a wide range of cervical compression severity. CR values were characterized on T1-weighted magnetic resonance imaging (MRI). Statistical significances in gait analysis parameters (speed, cadence, stride length, step with, and toe-out angle) were evaluated among different CR groups by the non-parametric Kruskal-Wallis test followed by the Mann-Whitney U test using Bonferroni correction. The Spearman test was performed to verify correlations between CR and gait parameters. The Kruskal-Wallis test revealed significant decline in gait speed and stride length and significant increase in toe-out angle with progression of cervical compression myelopathy. The post-hoc Mann-Whitney U test showed significant differences in these parameters between the control group (0.45

The role of grain size and shape in the strengthening of dispersion hardened nickel alloys

NASA Technical Reports Server (NTRS)

Wilcox, B. A.; Clauer, A. H.

1972-01-01

Thermomechanical processing was used to develop various microsstructures in Ni, Ni-2ThO2, Ni-20Cr, Ni-20CR-2ThO2, Ni-20Cr-10W-and Ni-20Cr-10W-2ThO2. The yield strength at 25 C increased with substructure refinement according to the Hall-Petch relation, and substructure refinement was a much more potent means of strengthening than was dispersion hardening. At elevated temperature (1093 C), the most important microstructural feature affecting strength was the grain aspect ratio (grain length, L, divided by grain width, 1. The yield strength and creep strength increased linearly with increasing L/1.

Morphology-Dependent Hardness of Cr7C3-Ni-Rich Alloy Composite vs Orientation Independent Hardness of Cr7C3 Primary Phase in a Laser Clad Microstructure

NASA Astrophysics Data System (ADS)

Venkatesh, Lakshmi Narayanan; Suresh Babu, Pitchuka; Gundakaram, Ravi Chandra; Doherty, Roger D.; Joshi, Shrikant V.; Samajdar, Indradev

2017-04-01

Microstructural evolution with superheating was studied in chromium carbide-nickel coatings deposited by laser cladding. At lower superheating, selective growth of <0001> direction from the high density of Cr7C3 grains nucleated resulted in a columnar structure with (0001) texture. Increased superheating lead to the loss of columnar structure as well as the (0001) texture. The hexagonal Cr7C3 showed an unusual isotropic nanoindentation hardness evidently correlated with its low c/ a ratio. However, the rod-like morphology of the carbide dendrites resulted in significant anisotropy in the hardness of the composite.

Control of relative carrier-envelope phase slip in femtosecond Ti:sapphire and Cr:forsterite lasers.

PubMed

Kobayashi, Yohei; Torizuka, Kenji; Wei, Zhiyi

2003-05-01

We were able to control relative carrier-envelope phase slip among mode-locked Ti:sapphire and Cr:forsterite lasers by employing electronic feedback. The pulse timings of these lasers were passively synchronized with our crossing-beam technique. Since the optical-frequency ratio of Ti:sapphire and Cr:forsterite is approximately 3:2, we can observe the phase relation by superimposing the third harmonic of Cr:forsterite and the second harmonic of Ti:sapphire lasers in time and in space. The spectrum width of the locked beat note was less than 3 kHz, which corresponds to the controlled fluctuation of a cavity-length difference of less than 10 pm.

Challenging Cosmic Ray Propagation with Antiprotons: Evidence for a "Fresh" Nuclei Component?

NASA Technical Reports Server (NTRS)

Moskalenko, Igor V.; Strong, Andrew W.; Mashnik, Stepan G.; Ormes, Jonathan F.

2002-01-01

Recent measurements of the cosmic ray (CR) antiproton flux have been shown to challenge existing CR propagation models. It was shown that the reacceleration models designed to match secondary to primary nuclei ratio (e.g., Boron/Carbon) produce too few antiprotons, while the traditional non-reacceleration models can reproduce the antiproton flux but fall short of explaining the low-energy decrease in the secondary to primary nuclei ratio. Matching both the secondary to primary nuclei ratio and antiproton flux requires artificial breaks in the diffusion coefficient and the primary injection spectrum suggesting the need for other approaches. In the present paper we discuss one possibility to overcome these difficulties. Using the measured antiproton flux to fix the diffusion coefficient, we show that the spectra of primary nuclei as measured in the heliosphere may contain a fresh local unprocessed component at low energies, thus decreasing the measured secondary to primary nuclei ratio. A model reproducing antiprotons, B/C ratio, and abundances up to Ni is presented.

Immobilization of hexavalent chromium in contaminated soils using biochar supported nanoscale iron sulfide composite.

PubMed

Lyu, Honghong; Zhao, Hang; Tang, Jingchun; Gong, Yanyan; Huang, Yao; Wu, Qihang; Gao, Bin

2018-03-01

Biochar supported carboxymethyl cellulose (CMC)-stabilized nanoscale iron sulfide (FeS) composite (CMC-FeS@biochar) was prepared and tested for immobilization of hexavalent chromium Cr(VI) in soil. Results of UV-vis and transmission electron microscopy (TEM) showed that the backbone of biochar suppressed the aggregation of FeS, resulting in smaller particle size and more sorption sites than bare FeS. The composite at a dosage of 2.5 mg per gram soil displayed an enhanced Cr(VI) immobilization efficiency (a 94.7% reduction in the toxicity characteristic leaching procedure (TCLP) based leachability and a 95.6% reduction in the CaCl 2 extraction) compared to plain biochar and bare FeS. Sequential extraction procedure (SEP) and X-ray photoelectron spectroscopy (XPS) analysis suggested that CMC-FeS@biochar promoted the conversion of more accessible Cr (exchangeable and carbonate-bound fractions) into the less accessible forms (iron-manganese oxides-bound, organic material-bound, and residual fractions) to reduce the toxicity of Cr(VI) and that surface sorption and reduction were dominant mechanisms for Cr(VI) immobilization. CMC-FeS@biochar greatly reduced the bioavailability of Cr(VI) to wheat and earthworms (Eisenia fetida). Moreover, the application of CMC-FeS@biochar enhanced soil organic matter content and microbial activity. This work highlighted the potential of CMC-FeS@biochar composite as a low-cost, "green", and effective amendment for immobilizing Cr(VI) in contaminated soils and improving soil properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

The research of axial corrosion fatigue on 10Ni3CrMoV steel

NASA Astrophysics Data System (ADS)

Xie, Xing; Yi, Hong; Xu, Jian; Xie, Kun

2017-09-01

Fatigue life had been studied with 10CrNi3MoV steel at different load ratios and in different environmental medias. The microstructure and micro-topography had been observed and analyzed by means of SEM, EDS and TEM. Our findings indicated that, the fatigue life of 10Ni3CrMoV steel in seawater was shorter than in air, the difference in longevity was larger with the decreasing of axis stress. Corrosion pits had a great influence on corrosion fatigue life.

The x ray microprobe determination of chromium oxidation state in olivine from lunar basalt and kimberlitic diamonds

NASA Technical Reports Server (NTRS)

Sutton, S. R.; Bajt, S.; Rivers, M. L.; Smith, J. V.

1993-01-01

The synchrotron x-ray microprobe is being used to obtain oxidation state information on planetary materials with high spatial resolution. Initial results on chromium in olivine from various sources including laboratory experiments, lunar basalt, and kimberlitic diamonds are reported. The lunar olivine was dominated by Cr(2+) whereas the diamond inclusions had Cr(2+/Cr(3+) ratios up to about 0.3. The simpliest interpretation is that the terrestrial olivine crystallized in a more oxidizing environment than the lunar olivine.

Proton Chemical Shift Imaging of the Brain in Pediatric and Adult Developmental Stuttering.

PubMed

O'Neill, Joseph; Dong, Zhengchao; Bansal, Ravi; Ivanov, Iliyan; Hao, Xuejun; Desai, Jay; Pozzi, Elena; Peterson, Bradley S

2017-01-01

Developmental stuttering is a neuropsychiatric condition of incompletely understood brain origin. Our recent functional magnetic resonance imaging study indicates a possible partial basis of stuttering in circuits enacting self-regulation of motor activity, attention, and emotion. To further characterize the neurophysiology of stuttering through in vivo assay of neurometabolites in suspect brain regions. Proton chemical shift imaging of the brain was performed in a case-control study of children and adults with and without stuttering. Recruitment, assessment, and magnetic resonance imaging were performed in an academic research setting. Ratios of N-acetyl-aspartate plus N-acetyl-aspartyl-glutamate (NAA) to creatine (Cr) and choline compounds (Cho) to Cr in widespread cerebral cortical, white matter, and subcortical regions were analyzed using region of interest and data-driven voxel-based approaches. Forty-seven children and adolescents aged 5 to 17 years (22 with stuttering and 25 without) and 47 adults aged 21 to 51 years (20 with stuttering and 27 without) were recruited between June 2008 and March 2013. The mean (SD) ages of those in the stuttering and control groups were 12.2 (4.2) years and 13.4 (3.2) years, respectively, for the pediatric cohort and 31.4 (7.5) years and 30.5 (9.9) years, respectively, for the adult cohort. Region of interest-based findings included lower group mean NAA:Cr ratio in stuttering than nonstuttering participants in the right inferior frontal cortex (-7.3%; P = .02), inferior frontal white matter (-11.4%; P < .001), and caudate (-10.6%; P = .04), while the Cho:Cr ratio was higher in the bilateral superior temporal cortex (left: +10.0%; P = .03 and right: +10.8%; P = .01), superior temporal white matter (left: +14.6%; P = .003 and right: +9.5%; P = .02), and thalamus (left: +11.6%; P = .002 and right: +11.1%; P = .001). False discovery rate-corrected voxel-based findings were highly consistent with region of interest findings. Additional voxel-based findings in the stuttering sample included higher NAA:Cr and Cho:Cr ratios (regression coefficient, 197.4-275; P < .001) in the posterior cingulate, lateral parietal, hippocampal, and parahippocampal cortices and amygdala, as well as lower NAA:Cr and Cho:Cr ratios (regression coefficient, 119.8-275; P < .001) in the superior frontal and frontal polar cortices. Affected regions comprised nodes of the Bohland speech-production (motor activity regulation), default-mode (attention regulation), and emotional-memory (emotion regulation) networks. Regional correlations were also observed between local metabolites and stuttering severity (r = 0.40-0.52; P = .001-.02). This spectroscopy study of stuttering demonstrates brainwide neurometabolite alterations, including several regions implicated by other neuroimaging modalities. Prior ascription of a role in stuttering to inferior frontal and superior temporal gyri, caudate, and other structures is affirmed. Consistent with prior functional magnetic resonance imaging findings, these results further intimate neurometabolic aberrations in stuttering in brain circuits subserving self-regulation of speech production, attention, and emotion.

Conversion of blood androgens to estrogens in normal adult men and women

PubMed Central

Longcope, Christopher; Kato, Tatsuo; Horton, Richard

1969-01-01

Continuous infusions of Δ4-androstenedione-7-3H and testosterone-7-3H have been used to demonstrate that these androgens are converted to estrone and 17β-estradiol, and contribute to the circulating blood levels of these estrogens in normal males and females. The conversion ratio (ratio of concentrations of radioactivity of free product steroid [χ-PRO] and free precursor steroid [χ-PRE], both corrected for recoveries, after an infusion of radioactive precursor steroid) for androstenedione (precursor) to estrone (product) is 0.013 in males and 0.007 in females, and the conversion ratio for testosterone (precursor) to estradiol (product) is 0.0018 in males and 0.005 in females. The transfer constant, [ρ]BBAE1, for androstenedione conversion to estrone ([ρ]BBAE1 = per cent of infused androstenedione, precursor, converted to estrone, product, when infusion and measurement are both in blood) is 1.35% in males and 0.74% in females, and the transfer constant, [ρ]BBTE2, for testosterone conversion to estradiol is 0.39% in males and 0.15% in females. Whether measured as conversion ratio or transfer constant, the peripheral aromatization of androstenedione takes place to a greater degree than that of testosterone, and, for the respective androgens, both the conversion ratio and [ρ]BB value are greater in males than females. For the androgen interconversions, [ρ]BBAT is 4.5% in males and 2.2% in females; [ρ]BBTA is 8.2% in males and 12.0% in females. Studies on the distribution coefficients (effective concentration in red cells/plasma) for precursor radioactivity were also made. In both males and females the distribution coefficient for androstenedione is 0.16-0.17 while that of testosterone is 0.01-0.03. PMID:5355335

Compound-Specific Carbon, Nitrogen, and Hydrogen Isotopic Ratios for Amino Acids in CM and CR Chondrites and their use in Evaluating Potential Formation Pathways

NASA Technical Reports Server (NTRS)

Elsila, Jamie E.; Charnley, Steven B.; Burton, Aaron S.; Glavin, Daniel P.; Dworkin, Jason P.

2012-01-01

Stable hydrogen, carbon, and nitrogen isotopic ratios (oD, 013C, and olSN) of organic compounds can revcal information about their origin and formation pathways. Several formation mechanisms and environments have been postulated for the amino acids detected in carbonaceous chondrites. As each proposed mechanism utilizes different precursor molecules, the isotopic signatures of the resulting amino acids may indicate the most likely of these pathways. We have applied gas chromatography with mass spectrometry and combustion isotope ratio mass spectrometry to measure the compound-specific C, N, and H stable isotopic ratios of amino acids from seven CM and CR carbonaceous chondrites: CM1I2 Allan Hills (ALH) 83100, CM2 Murchison, CM2 Lewis Cliff (LEW) 90500, CM2 Lonewolf Nunataks (LON) 94101, CRZ Graves Nunataks (GRA) 95229, CRZ Elephant Moraine (EET) 92042, and CR3 Queen Alexandra Range (QUE) 99177. We compare the isotopic compositions of amino acids in these meteorites with predictions of expected isotopic enrichments from potential formation pathways. We observe trends of decreasing ODC and increasing oD with increasing carbon number in the aH, (l-NH2 amino acids that correspond to predictions made for formation via Streckercyanohydrin synthesis. We also observe light ODC signatures for -alanine, which may indicate either formation via Michael addition or via a pathway that forms primarily small, straight-chain, amine-terminal amino acids (n-ro-amino acids). Higher deuterium enrichments are observed in amethyl amino acids, indicating formation of these amino acids or their precursors in cold interstellar or nebular environments. Finally, individual amino acids are more enriched in deuterium in CR chondrites than CM chondrites, reflecting different parent-body chemistry.

Differentiation between malignant and non-malignant pleural effusion using cancer ratio and other new parameters.

PubMed

Korczynski, Piotr; Mierzejewski, Michal; Krenke, Rafal; Safianowska, Aleksandra; Light, Richard W

2018-06-05

Introduction In contrast to tuberculous pleurisy (TP), no accurate and commonly accepted biochemical marker of malignant pleural effusion (MPE) has been established. Objectives We aimed to: 1) evaluate the ability of previously reported cancer ratio (CR) to discriminate MPEs and non-MPEs, 2) test whether age may have additional value in differentiating MPEs and non MPEs, and if so, 3) to combine LDH and age with other TP biomarkers in search of an index useful in the identification of MPE. Patients and methods A retrospective analysis of data from 140 patients with malignant (n=74), tuberculous (n=37) and parapneumonic (n=29) pleural effusions was performed. The diagnostic performance of a test to discriminate between MPEs and non-MPEs was evaluated using Receiver Operating Characteristic. Results Three ratios showed the largest AUC: serum LDH/pleural fluid soluble Fas ligand, age/pleural fluid ADA and serum LDH/pleural fluid IL-18 and were characterized by a high sensitivity (95, 93.2, 92.9% respectively) and fair specificity (64.8, 71.2, 58.5% respectively) in discrimination MPE from non-MPEs. AUC for CR was lower than for aforementioned values and showed 94.6% sensitivity and 68.2% specificity. Conclusions Our study showed a lower specificity of CR in discriminating MPEs and non-MPEs than previously reported. We demonstrated that combinations of serum LDH with other pleural fluid biomarkers of TP have a similar diagnostic performance. We also found that age might be an important factor differentiating between MPEs and non-MPEs and propose a new age/pleural fluid ADA ratio which has a discriminative potential similar to that of CR.

Five-year clinical outcomes of everolimus-eluting stents from the post marketing study of CoCr-EES (XIENCE V/PROMUS) in Japan.

PubMed

Aoki, Jiro; Kozuma, Ken; Awata, Masaki; Nanasato, Mamoru; Shiode, Nobuo; Tanabe, Kengo; Yamaguchi, Junichi; Kusano, Hajime; Nie, Hong; Kimura, Takeshi

2018-02-26

The Cobalt Chromium Everolimus-Eluting Stent (CoCr-EES) Post Marketing Surveillance (PMS) Japan study is a prospective multicenter registry designed to evaluate the safety and efficacy of XIENCE V/PROMUS everolimus-eluting stents in routine clinical practice at 47 centers representative of the clinical environment in Japan. We enrolled 2010 consecutive patients (2649 lesions) who underwent percutaneous coronary intervention using CoCr-EES. Clinical outcomes were evaluated through 5 years. Mean age was 68.8 years, 41.9% had diabetes, 4.9% received hemodialysis. Five-year clinical follow up was available for 1704 (84.8%) patients. Major adverse cardiovascular events (MACE) occurred in 10.7% of patients, including cardiac death (3.8%), myocardial infarction (1.8%), and clinically driven target lesion revascularization (TLR) (6.0%). Beyond 1 year, annual incidence of clinically driven TLR was 0.5-0.8%. Definite or probable stent thrombosis occurred in 9 (0.5%) patients at 5 years. After 1 year, definite stent thrombosis occurred in only 1 patient. Significant predictors for MACE were dialysis (ODDs ratio 4.58, 95% CI 2.75-7.64), prior cardiac intervention (ODDs ratio 2.47, 95% CI 1.75-3.49), total stent length (ODDs ratio 1.01, 95% CI 1.01-1.02), and number of diseased vessels (ODDs ratio 1.66, 95% CI 1.08-2.55). Five-year clinical outcomes from the CoCr-EES PMS Japan study demonstrated a low incidence of clinical events in the daily practice up to 5 years. https://clinicaltrials.gov/ct2/show/NCT01086228 .

Neonatal hydrocortisone treatment related to 1H-MRS of the hippocampus and short-term memory at school age in preterm born children.

PubMed

Rademaker, Karin J; Rijpert, Maarten; Uiterwaal, Cuno S P M; Lieftink, Arno F; van Bel, Frank; Grobbee, Diederick E; de Vries, Linda S; Groenendaal, Floris

2006-02-01

Animal studies have shown that corticosteroids (dexamethasone) cause neuronal loss in the hippocampus and deficits in short term memory. Proton magnetic resonance spectroscopy can measure brain metabolites in vivo and give an indication of neuronal integrity. We investigated whether prolonged administration of hydrocortisone during the neonatal period for bronchopulmonary dysplasia (BPD) in preterm born children changes the metabolism in the hippocampus, measured at school age. Secondly, we investigated whether hippocampal metabolism and short-term memory and neurodevelopmental outcome are related. In this observational study 37 preterm born children (< or = 32 wk (range 25.0-33.0) and/or a birth weight < or = 1500 g) underwent proton spectroscopy of the hippocampus at school age. Eighteen children were treated with hydrocortisone for BPD (starting dose 5 mg/kg/d tapered over a minimum period of 22 d, median duration 28 d) and 19 never received corticosteroids during the perinatal period. N-acetyl aspartate/ Choline + Creatine/phosphocreatine (NAA/(Cho + Cr)) ratios were determined. A 15-word recall memory test and an IQ measurement were obtained on the same day. Hydrocortisone treated children were younger, lighter and sicker than their nonsteroid treated counterparts. Mean NAA/(Cho + Cr) ratios in the hippocampus were not significantly different in the hydrocortisone group compared with the non-steroid group. Performance on the 15-word memory test and IQ were similar in the two groups. There was no relation between NAA/(Cho + Cr) ratios and memory nor between NAA/(Cho + Cr) ratios and IQ. We conclude that hydrocortisone in the mentioned dose, administered in the neonatal period for BPD, does not appear to have any long-term effects on memory and/or hippocampal metabolism.

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

Zhao, Xianhui; Ngo, Huong T.; Walker, Devin M.

The performance of catalytic tri-reforming under industrially relevant situations (e.g., pellet catalysts, pressurized reactor) was investigated using surrogate biogas as the feedstock. Tri-reforming using Ni/Mg/Ce 0.6Zr 0.4O 2/Al 2O 3 pellet catalysts was studied in a bench scale fixed-bed reactor. The feed molar ratio for CH 4: CO 2: air was fixed as 1.0: 0.70: 0.95. The effects of temperature (800 – 860 °C), pressure (1 – 6 bar), and H 2O/CH 4 molar feed ratio (0.23 – 0.65) were examined. Pressure has substantial impact on the reaction and transport rates and equilibrium conversions, making it a key variable. Atmore » 860 °C, CO 2 conversion increased from 4 to 61% and H 2/CO molar ratio decreased from 2.0 to 1.1 as the pressure changed from 1 to 6 bar. CO 2 conversion and H 2/CO molar ratio were also influenced by the temperature and H 2O/CH 4 molar ratio. At 3 bar, CO 2 conversion varied between 4 and 43% and the H 2/CO molar ratio varied between 1.2 and 1.9 as the temperature changed from 800 to 860 °C. At 3 bar and 860 °C, CO 2 conversion decreased from 35 to 8% and H 2/CO molar ratio increased from 1.7 to 2.4 when the H 2O/CH 4 molar ratio was increased from 0.23 to 0.65. This work demonstrates that the tri-reforming technology is feasible for converting biogas under scaled-up conditions in a fixed-bed reactor.« less

Tri-reforming of surrogate blogs over Ni/Mg/ceria-zirconia/alumina pellet catalysts

DOE PAGES

Zhao, Xianhui; Ngo, Huong T.; Walker, Devin M.; ...

2018-01-23

The performance of catalytic tri-reforming under industrially relevant situations (e.g., pellet catalysts, pressurized reactor) was investigated using surrogate biogas as the feedstock. Tri-reforming using Ni/Mg/Ce 0.6Zr 0.4O 2/Al 2O 3 pellet catalysts was studied in a bench scale fixed-bed reactor. The feed molar ratio for CH 4: CO 2: air was fixed as 1.0: 0.70: 0.95. The effects of temperature (800 – 860 °C), pressure (1 – 6 bar), and H 2O/CH 4 molar feed ratio (0.23 – 0.65) were examined. Pressure has substantial impact on the reaction and transport rates and equilibrium conversions, making it a key variable. Atmore » 860 °C, CO 2 conversion increased from 4 to 61% and H 2/CO molar ratio decreased from 2.0 to 1.1 as the pressure changed from 1 to 6 bar. CO 2 conversion and H 2/CO molar ratio were also influenced by the temperature and H 2O/CH 4 molar ratio. At 3 bar, CO 2 conversion varied between 4 and 43% and the H 2/CO molar ratio varied between 1.2 and 1.9 as the temperature changed from 800 to 860 °C. At 3 bar and 860 °C, CO 2 conversion decreased from 35 to 8% and H 2/CO molar ratio increased from 1.7 to 2.4 when the H 2O/CH 4 molar ratio was increased from 0.23 to 0.65. This work demonstrates that the tri-reforming technology is feasible for converting biogas under scaled-up conditions in a fixed-bed reactor.« less

Studies on antidyslipidemic effects of Morinda citrifolia (Noni) fruit, leaves and root extracts

PubMed Central

2010-01-01

Background The objective of present study was to provide the pharmacological basis for the medicinal use of Morinda citrifolia Linn in dyslipidemia using the aqueous-ethanolic extracts of its fruits (Mc.Cr.F), leaves (Mc.Cr.L) and roots (Mc.Cr.R). Results Mc.Cr.F, Mc.Cr.L and Mc.Cr.R showed antidyslipidemic effects in both triton (WR-1339) and high fat diet-induced dyslipidemic rat models to variable extents. All three extracts caused reduction in total cholesterol and triglyceride levels in triton-induced dyslipidemia. In high fat diet-induced dyslipidemia all these extracts caused significant reduction in total cholesterol, triglyceride, low density lipoprotein-cholesterol (LDL-C), atherogenic index and TC/HDL ratio. Mc.Cr.R extract also caused increase in high density lipoprotein-cholesterol (HDL-C). The Mc.Cr.L and Mc.Cr.R reduced gain in body weight with a reduction in daily diet consumption but Mc.Cr.F had no effect on body weight and daily diet consumption. Conclusions These data indicate that the antidyslipidemic effect of the plant extracts was meditated through the inhibition of biosynthesis, absorption and secretion of lipids. This may be possibly due partly to the presence of antioxidant constituents in this plant. Therefore, this study rationalizes the medicinal use of Morinda citrifolia in dyslipidemia. PMID:20727145

Studies on antidyslipidemic effects of Morinda citrifolia (Noni) fruit, leaves and root extracts.

PubMed

Mandukhail, Saf-ur Rehman; Aziz, Nauman; Gilani, Anwarul-Hassan

2010-08-20

The objective of present study was to provide the pharmacological basis for the medicinal use of Morinda citrifolia Linn in dyslipidemia using the aqueous-ethanolic extracts of its fruits (Mc.Cr.F), leaves (Mc.Cr.L) and roots (Mc.Cr.R). Mc.Cr.F, Mc.Cr.L and Mc.Cr.R showed antidyslipidemic effects in both triton (WR-1339) and high fat diet-induced dyslipidemic rat models to variable extents. All three extracts caused reduction in total cholesterol and triglyceride levels in triton-induced dyslipidemia. In high fat diet-induced dyslipidemia all these extracts caused significant reduction in total cholesterol, triglyceride, low density lipoprotein-cholesterol (LDL-C), atherogenic index and TC/HDL ratio. Mc.Cr.R extract also caused increase in high density lipoprotein-cholesterol (HDL-C). The Mc.Cr.L and Mc.Cr.R reduced gain in body weight with a reduction in daily diet consumption but Mc.Cr.F had no effect on body weight and daily diet consumption. These data indicate that the antidyslipidemic effect of the plant extracts was meditated through the inhibition of biosynthesis, absorption and secretion of lipids. This may be possibly due partly to the presence of antioxidant constituents in this plant. Therefore, this study rationalizes the medicinal use of Morinda citrifolia in dyslipidemia.

Ethanol production from a biomass mixture of furfural residues with green liquor-peroxide saccarified cassava liquid.

PubMed

Ji, Li; Zheng, Tianran; Zhao, Pengxiang; Zhang, Weiming; Jiang, Jianxin

2016-06-01

As the most abundant renewable resources, lignocellulosic materials are ideal candidates as alternative feedstock for bioethanol production. Cassava residues (CR) are byproducts of the cassava starch industry which can be mixed with lignocellulosic materials for ethanol production. The presence of lignin in lignocellulosic substrates can inhibit saccharification by reducing the cellulase activity. Simultaneous saccharification and fermentation (SSF) of furfural residues (FR) pretreated with green liquor and hydrogen peroxide (GL-H2O2) with CR saccharification liquid was investigated. The final ethanol concentration, yield, initial rate, number of live yeast cells, and the dead yeast ratio were compared to evaluate the effectiveness of combining delignificated lignocellulosic substrates and starchy substrates for ethanol production. Our results indicate that 42.0 % of FR lignin removal was achieved on FR using of 0.06 g H2O2/g-substrate and 9 mL GL/g-substrate at 80 °C. The highest overall ethanol yield was 93.6 % of the theoretical. When the ratio of 0.06 g/g-H2O2-GL-pretreated FR to CR was 5:1, the ethanol concentration was the same with that ratio of untreated FR to CR of 1:1. Using 0.06 g/g-H2O2-GL-pretreated FR with CR at a ratio of 2:1 resulted in 51.9 g/L ethanol concentration. Moreover, FR pretreated with GL-H2O2 decreased the concentration of byproducts in SSF compared with that obtained in the previous study. The lignin in FR would inhibit enzyme activity and GL-H2O2 is an advantageous pretreatment method to treat FR and high intensity of FR pretreatment increased the final ethanol concentration. The efficiency of ethanol fermentation of was improved when delignification increased. GL-H2O2 is an advantageous pretreatment method to treat FR. As the pretreatment dosage of GL-H2O2 on FR increased, the proportion of lignocellulosic substrates was enhanced in the SSF of the substrate mixture of CR and FR as compared with untreated FR. Moreover, the final ethanol concentration was increased with a high ethanol yield and lower byproduct concentrations.

MR spectroscopy of intracranial tuberculomas: A singlet peak at 3.8 ppm as potential marker to differentiate them from malignant tumors

PubMed Central

Alfaro, David; Martinot, Carlos; Fayed, Nicolas; Gaskill-Shipley, Mary

2015-01-01

Purpose The diagnosis of intracranial tuberculomas is often challenging. Our purpose is to describe the most common metabolic patterns of tuberculomas by MR spectroscopy (MRS) with emphasis on potential specific markers. Methods Single-voxel MRS short echo time was performed in 13 cases of tuberculomas proven by histology and/or response to anti-mycobacterial therapy. For comparison MRS was also performed in 19 biopsy-proven malignant tumors (13 high-grade gliomas and six metastasis). Presence of metabolic peaks was assessed visually and categorical variables between groups were compared using chi-square. Metabolite ratios were compared using Mann-Whitney test and diagnostic accuracy of the metabolite ratios was compared using receiver-operating characteristic (ROC) curves analysis. Results Spectroscopic peaks representing lipids and glutamate/glutamine (Glx) as well as a peak at ∼3.8 ppm were well defined in 77% (10/13), 77% (10/13) and 69% (nine of 13) of tuberculomas, respectively. Lipid and Glx peaks were also present in most of the malignant lesions, 79% (15/19) and 74% (14/19) respectively. However, a peak at ∼3.8 ppm was present in only 10% (two of 19) of the tumor cases (p < 0.001). Higher Cho/Cr and mI/Cr ratios helped discriminate malignant lesions with an area under the ROC curve of 0.86 (SE: 0.078, p < 0.002, CI: 0.7–1) and 0.8 (SE: 0.1, p < 0.009, CI: 0.6–1), respectively. Threshold values between 1.7–1.9 for Cho/Cr and 0.8–0.9 for mI/Cr provided high specificity (91% for both metabolites) and adequate sensitivity (75% and 80%, respectively) for discrimination of malignant lesions. Conclusion A singlet peak at ∼3.8 ppm is present in the majority of tuberculomas and absent in most malignant tumors, potentially a marker to differentiate these lesions. The assignment of the peak is difficult from our analysis; however, guanidinoacetate (Gua) is a possibility. Higher Cho/Cr and mI/Cr ratios should favor malignant lesions over tuberculomas. The presence of lipids and Glx is non-specific. PMID:26246099

Remediation of hexavalent chromium spiked soil by using synthesized iron sulfide particles.

PubMed

Li, Yujie; Wang, Wanyu; Zhou, Liqiang; Liu, Yuanyuan; Mirza, Zakaria A; Lin, Xiang

2017-02-01

Carboxymethyl cellulose (CMC) stabilized microscale iron sulfide (FeS) particles were synthesized and applied to remediate hexavalent chromium (Cr(VI)) spiked soil. The effects of parameters including dosage of FeS particles, soil moisture, and natural organic matter (NOM) in soil were investigated with comparison to iron sulfate (FeSO 4 ). The results show that the stabilized FeS particles can reduce Cr(VI) and immobilize Cr in soil quickly and efficiently. The soil moisture ranging from 40% to 70% and NOM in soil had no significant effects on Cr(VI) remediation by FeS particles. When molar ratio of FeS to Cr(VI) was 1.5:1, about 98% of Cr(VI) in soil was reduced by FeS particles in 3 d and Cr(VI) concentration decreased from 1407 mg kg -1 to 16 mg kg -1 . The total Cr and Cr(VI) in Toxicity Characteristic Leaching Procedure (TCLP) leachate were reduced by 98.4% and 99.4%, respectively. In FeS particles-treated soil, the exchangeable Cr fraction was mainly converted to Fe-Mn oxides bound fraction because of the precipitation of Cr(III)-Fe(III) hydroxides. The physiologically based extraction test (PBET) bioaccessibility of Cr was decreased from 58.67% to 6.98%. Compared to FeSO 4 , the high Cr(VI) removal and Cr immobilization efficiency makes prepared FeS particles a great potential in field application of Cr(VI) contaminated soil remediation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Optimization of reactive-ion etching (RIE) parameters for fabrication of tantalum pentoxide (Ta2O5) waveguide using Taguchi method

NASA Astrophysics Data System (ADS)

Muttalib, M. Firdaus A.; Chen, Ruiqi Y.; Pearce, S. J.; Charlton, Martin D. B.

2017-11-01

In this paper, we demonstrate the optimization of reactive-ion etching (RIE) parameters for the fabrication of tantalum pentoxide (Ta2O5) waveguide with chromium (Cr) hard mask in a commercial OIPT Plasmalab 80 RIE etcher. A design of experiment (DOE) using Taguchi method was implemented to find optimum RF power, mixture of CHF3 and Ar gas ratio, and chamber pressure for a high etch rate, good selectivity, and smooth waveguide sidewall. It was found that the optimized etch condition obtained in this work were RF power = 200 W, gas ratio = 80 %, and chamber pressure = 30 mTorr with an etch rate of 21.6 nm/min, Ta2O5/Cr selectivity ratio of 28, and smooth waveguide sidewall.

Transplantation Outcomes for Children with Hypodiploid Acute Lymphoblastic Leukemia.

PubMed

Mehta, Parinda A; Zhang, Mei-Jie; Eapen, Mary; He, Wensheng; Seber, Adriana; Gibson, Brenda; Camitta, Bruce M; Kitko, Carrie L; Dvorak, Christopher C; Nemecek, Eneida R; Frangoul, Haydar A; Abdel-Azim, Hisham; Kasow, Kimberly A; Lehmann, Leslie; Gonzalez Vicent, Marta; Diaz Pérez, Miguel A; Ayas, Mouhab; Qayed, Muna; Carpenter, Paul A; Jodele, Sonata; Lund, Troy C; Leung, Wing H; Davies, Stella M

2015-07-01

Children with hypodiploid acute lymphoblastic leukemia (ALL) have inferior outcomes despite intensive risk-adapted chemotherapy regimens. We describe 78 children with hypodiploid ALL who underwent hematopoietic stem cell transplantation between 1990 and 2010. Thirty-nine (50%) patients had ≤ 43 chromosomes, 12 (15%) had 44 chromosomes, and 27 (35%) had 45 chromosomes. Forty-three (55%) patients underwent transplantation in first remission (CR1) and 35 (45%) underwent transplantation in ≥ second remission (CR2). Twenty-nine patients (37%) received a graft from a related donor and 49 (63%) from an unrelated donor. All patients received a myeloablative conditioning regimen. The 5-year probabilities of leukemia-free survival, overall survival, relapse, and treatment-related mortality for the entire cohort were 51%, 56%, 27%, and 22%, respectively. Multivariate analysis confirmed that mortality risks were higher for patients who underwent transplantation in CR2 (hazard ratio, 2.16; P = .05), with number of chromosomes ≤ 43 (hazard ratio, 2.15; P = .05), and for those who underwent transplantation in the first decade of the study period (hazard ratio, 2.60; P = .01). Similarly, treatment failure risks were higher with number of chromosomes ≤ 43 (hazard ratio, 2.28; P = .04) and the earlier transplantation period (hazard ratio, 2.51; P = .01). Although survival is better with advances in donor selection and supportive care, disease-related risk factors significantly influence transplantation outcomes. Copyright © 2015 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

The structure of Medicago truncatula δ 1-pyrroline-5-carboxylate reductase provides new insights into regulation of proline biosynthesis in plants

DOE PAGES

Ruszkowski, Milosz; Nocek, Boguslaw; Forlani, Giuseppe; ...

2015-10-30

The two pathways for proline biosynthesis in higher plants share the last step, the conversion of δ 1-pyrroline-5-carboxylate (P5C) to L-proline, which is catalyzed by P5C reductase (P5CR, EC 1.5.1.2) with the use of NAD(P)H as a coenzyme. There is increasing amount of evidence to suggest a complex regulation of P5CR activity at the post-translational level, yet the molecular basis of these mechanisms is unknown. Here we report the three-dimensional structure of the P5CR enzyme from the model legume Medicago truncatula (Mt). The crystal structures of unliganded MtP5CR decamer, and its complexes with the products NAD +, NADP +, andmore » L-proline were refined using x-ray diffraction data (at 1.7, 1.85, 1.95, and 2.1 Å resolution, respectively). Based on the presented structural data, the coenzyme preference for NADPH over NADH was explained, and NADPH is suggested to be the only coenzyme used by MtP5CR in vivo. Moreover, the insensitivity of MtP5CR to feed-back inhibition by proline, revealed by enzymatic analysis, was correlated with structural features. Additionally, a mechanism for the modulation of enzyme activity by chloride anions is discussed, as well as the rationale for the possible development of effective enzyme inhibitors.« less

Hydrogen sulfide interacts with calcium signaling to enhance the chromium tolerance in Setaria italica.

PubMed

Fang, Huihui; Jing, Tao; Liu, Zhiqiang; Zhang, Liping; Jin, Zhuping; Pei, Yanxi

2014-12-01

The oscillation of intracellular calcium (Ca(2+)) concentration is a primary event in numerous biological processes in plants, including stress response. Hydrogen sulfide (H2S), an emerging gasotransmitter, was found to have positive effects in plants responding to chromium (Cr(6+)) stress through interacting with Ca(2+) signaling. While Ca(2+) resemblances H2S in mediating biotic and abiotic stresses, crosstalk between the two pathways remains unclear. In this study, Ca(2+) signaling interacted with H2S to produce a complex physiological response, which enhanced the Cr(6+) tolerance in foxtail millet (Setaria italica). Results indicate that Cr(6+) stress activated endogenous H2S synthesis as well as Ca(2+) signaling. Moreover, toxic symptoms caused by Cr(6+) stress were strongly moderated by 50μM H2S and 20mM Ca(2+). Conversely, treatments with H2S synthesis inhibitor and Ca(2+) chelators prior to Cr(6+)-exposure aggravated these toxic symptoms. Interestingly, Ca(2+) upregulated expression of two important factors in metal metabolism, MT3A and PCS, which participated in the biosynthesis of heavy metal chelators, in a H2S-dependent manner to cope with Cr(6+) stress. These findings also suggest that the H2S dependent pathway is a component of the Ca(2+) activating antioxidant system and H2S partially contributes Ca(2+)-activating antioxidant system. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Metabolic disturbance of tryptophan-nicotinamide conversion pathway by putative endocrine disruptors, bisphenol A and styrene monomer].

PubMed

Fukuwatari, Tsutomu; Toriochi, Mai; Ohta, Mari; Sasaki, Ryuzo; Shibata, Katsumi

2004-02-01

Bisphenol A, a monomer of polycarbonate plastics, disturbed the conversion pathway of the amino acid tryptophan to the vitamin nicotinamide. The conversion ratio of tryptophan to nicotinamide was reduced to 1/15 by feeding a diet containing 1% bisphenol A. A putative disturbing reaction is kynurenine-->3-hydroxykynurenine, which is catalyzed by kynurenine monohydroxylase. This is an FAD-enzyme and requires NADPH as a coenzyme. Styrene monomer (1% addition to a normal diet) did not affect the food intake or the body weight, but slightly reduced the conversion ratio of tryptophan-nicotinamide.

Hexavalent chromium removal by chitosan modified-bioreduced nontronite

NASA Astrophysics Data System (ADS)

Singh, Rajesh; Dong, Hailiang; Zeng, Qiang; Zhang, Li; Rengasamy, Karthikeyan

2017-08-01

Recent efforts have focused on structural Fe(II) in chemically or biologically reduced clay minerals to immobilize Cr(VI) from aqueous solution, but the coulombic repulsion between the negatively charged clay surface and the polyanionic form of Cr(VI), e.g., dichromate, can hinder the effectiveness of this process. The purpose of this study was to investigate the efficiency and mechanism of Cr(VI) removal by a charge-reversed nontronite (NAu-2), an Fe-rich smectite. Chitosan, a linear polysaccharide derived from chitin found in soil and groundwater, was used to reverse the charge of NAu-2. Intercalation of chitosan into NAu-2 interlayer increased the basal d-spacing of NAu-2 from 1.23 nm to 1.83 nm and zeta potential from -27.17 to +34.13 mV, with the amount of increase depending on chitosan/NAu-2 ratio. Structural Fe(III) in chitosan-exchanged NAu-2 was then biologically reduced by an iron-reducing bacterium Shewanella putrefaciens CN32 in bicarbonate buffer with lactate as the sole electron donor, with and without electron shuttle, AQDS. Without AQDS, the extent of Fe(III) reduction increased from the lowest (∼9%) for the chitosan-free NAu-2 to the highest (∼12%) for the highest chitosan loaded NAu-2 (3:1 ratio). This enhancement of Fe(III) reduction was likely due to the attachment of negatively charged bacterial cells to charge-reversed (e.g., positively charged) NAu-2 surfaces, facilitating the electron transfer between cells and structural Fe(III). With AQDS, Fe(III) reduction extent doubled relative to those without AQDS, but the enhancement effect was similar across all chitosan loadings, suggesting that AQDS was more important than chitosan in enhancing Fe(III) bioreduction. Chitosan-exchanged, biologically reduced NAu-2 was then utilized for removing Cr(VI) in batch experiments with three consecutive spikes of 50 μM Cr. With the first Cr spike, the rate of Cr(VI) removal by charged-reversed NAu-2 that was bioreduced without and with AQDS was ∼1.5 and ∼6 μmol g-1 h-1, respectively. However, the capacity of these clays to remove Cr(VI) was progressively exhausted upon addition of subsequent Cr spikes. X-ray photoelectron spectroscopy (XPS) revealed that the reduction product of Cr(VI) by chitosan-exchanged-bioreduced NAu-2 was Cr(III), possibly in the form of Cr(OH)3. In summary, our results demonstrated that the combined effects of sorption and redox reactions by charge-reversed bioreduced nontronite may offer a feasible in-situ approach for remediating Cr(VI) polluted soil and groundwater.

Disrupted metabolic and functional connectivity patterns of the posterior cingulate cortex in cirrhotic patients: a study combining magnetic resonance spectroscopy and resting-state functional magnetic resonance imaging.

PubMed

Lu, Li; Wang, Junpeng; Zhang, Longjiang; Zhang, Zhiqiang; Ni, Ling; Qi, Rongfeng; Kong, Xiang; Lu, Mengjie; Sami, Muhammad U; Xu, Kai; Lu, Guangming

2018-06-26

The association between metabolic activity and functional coupling of the posterior cingulate cortex (PCC) in cirrhotic patients remains undefined. Therefore, this study aimed to assess the association of functional coupling with metabolic patterns of PCC in resting cirrhotic patients. Twenty-six cirrhotic patients, including 10 with hepatic encephalopathy (HE) and 16 without HE, were assessed, alongside 21 control participants. Single-voxel proton magnetic resonance spectroscopy (MRS) of the PCC and resting-state functional MRI (rs-fMRI) were performed on a 3.0-T MR scanner. The ratios of all metabolites to creatine (Cr) and rs-fMRI parameters [including amplitude of low-frequency fluctuation (ALFF), node degree (Ki), and betweenness centrality (Bi)] were evaluated by analysis of variance. Associations of metabolite ratios with rs-fMRI parameters and venous ammonia were determined by Pearson's correlation analysis. Lower chlorine (Cho)/Cr (0.6±0.2 vs. 0.9±0.1, P<0.001) and higher ALFF (1.3±0.5 vs. 1.1±0.3, P=0.01) were found in cirrhotic patients in comparison with controls. In cirrhotic patients, the ALFF values correlated negatively with Cho/Cr (r=-0.397, P=0.044). Meanwhile, Bi values showed positive associations with glutamine+glutamate/Cr (r=0.500, P=0.009) and N-acetyl aspartate/Cr (r=0.581, P=0.006). In the HE subgroup, Ki correlated positively with Cho/Cr (r=0.867, P=0.001). In cirrhotic patients without HE, Bi values showed a high positive correlation with glutamate+glutamine/Cr (r=0.690, P=0.013). These findings suggest a close association between metabolic activity and functional coupling of the PCC in cirrhotic patients, especially those with HE, whose node degree of the PCC shows an overt positive correlation with Cho/Cr.

Effect of dietary chromium picolinate on growth performance and blood parameters in grass carp fingerling, Ctenopharyngodon idellus.

PubMed

Liu, Tailiang; Wen, Hua; Jiang, Ming; Yuan, Danning; Gao, Pan; Zhao, Yujiang; Wu, Fan; Liu, Wei

2010-09-01

An experiment was conducted to investigate the effect of dietary chromium picolinate supplement on growth and haematology parameters of grass carp, Ctenopharyngodon idellus. Six diets with increasing dietary chromium picolinate levels 0, 0.2, 0.4, 0.8, 1.6 and 3.2 mg kg(-1) were fed to triplicate groups of 20 fish (initial weight of 12.78 +/- 1.16 g, mean +/- SD) in a flow water system for 10 weeks. Fish fed the diet supplemented with 0.8 mg Cr kg(-1) had significantly improved weight gain (WG), feed efficiency ratio (FER), protein efficiency ratio (PER) and protein retention (PR). Fish fed high-chromium diets exhibited lower whole-body crude lipid contents than fish fed low-chromium diets. Liver glycogen concentrations for fish fed the diet with 0.2 mg Cr kg(-1) was the highest (77.67 mg g(-1)). Fish fed the diet supplemented with 1.6 and 3.2 mg Cr kg(-1) had significantly lower liver glycogen concentrations than other groups (P < 0.05). The highest serum insulin concentrations were observed in fish fed the diet supplemented with 0.8 mg Cr kg(-1), but serum insulin concentrations decreased (P < 0.05) when dietary supplementation of chromium was higher than 0.8 mg Cr kg(-1). Cholesterol concentrations decreased in direct proportion to dietary chromium level and achieved the lowest level when the fish were fed the 0.8 mg Cr kg(-1) diet, but increased when the fish were fed the diet with more than 0.8 mg Cr kg(-1) (P < 0.05). Fish fed the diet supplemented with 0.8 mg Cr kg(-1) had higher triglyceride and high-density lipoprotein cholesterol (HDL-C) concentrations compared to other treatments. The results of the present study suggested that chromium picolinate could modify serum carbohydrate and lipid metabolism profile, and that the optimal dietary chromium level was 0.8 mg kg(-1) for grass carp according to growth.

Comparative Effectiveness of Published Interventions for Elderly Fall Prevention: A Systematic Review and Network Meta-Analysis.

PubMed

Cheng, Peixia; Tan, Liheng; Ning, Peishan; Li, Li; Gao, Yuyan; Wu, Yue; Schwebel, David C; Chu, Haitao; Yin, Huaiqiong; Hu, Guoqing

2018-03-12

Falls are a major threat to older adults worldwide. Although various effective interventions have been developed, their comparative effectiveness remains unreported. A systematic review and network meta-analysis was conducted to determine the most effective interventions to prevent falls in community-dwelling adults aged 60 and over. Combined odds ratio (OR) and 95% credible interval (95% CrI) were calculated. A total of 49 trials involving 27,740 participants and 9271 fallers were included. Compared to usual care, multifactorial interventions (MFI) demonstrated the greatest efficacy (OR: 0.64, 95% CrI: 0.53 to 0.77) followed by interventions combining education and exercise (EDU + EXC) (OR: 0.65, 95% CrI: 0.38 to 1.00) and interventions combining exercise and hazard assessment and modification (EXC + HAM) (OR: 0.66, 95% CrI: 0.40 to 1.04). The effect of medical care performed the worst (OR: 1.02, 95% CrI: 0.78 to 1.34). Model fit was good, inconsistency was low, and publication bias was considered absent. The overall quality of included trials was high. The pooled odds ratios and ranking probabilities remained relatively stable across all sensitivity analyses. MFI and exercise appear to be effective to reduce falls among older adults, and should be considered first as service delivery options. Further investigation is necessary to verify effectiveness and suitableness of the strategies to at-risk populations.

Neural metabolite changes in corpus striatum after rat multipotent mesenchymal stem cells transplanted in hemiparkinsonian rats by magnetic resonance spectroscopy.

PubMed

Fu, Wenyu; Zheng, Zhijuan; Zhuang, Wenxin; Chen, Dandan; Wang, Xiaocui; Sun, Xihe; Wang, Xin

2013-12-01

To investigate the biochemical changes in striatum after rat bone marrow mesenchymal stem cells (MSCs) were transplanted into hemiparkinsonian rats and to further confirm the therapeutic effects of rat MSCs for Parkinson's disease (PD). 5-bromo-2-deoxyuridine (BrdU)-labeled MSCs were transplanted into the corpus striatum of the 6-hydroxydopamine (6-OHDA)-injected side of six PD model rats. Before and 8 weeks after MSC transplantation, ethological changes in PD rats were assessed. The expression of tyrosine hydroxylase (TH) in substantia nigra (SN) and striatum were measured using immunohistochemical methods. The differentiation of MSCs was detected by double immunofluorescence techniques. The concentrations of neural metabolites of N-acetylaspartate (NAA), choline (Cho) and creatine (Cr) were measured by ¹H-magnetic resonance spectroscopy (MRS). Relative concentrations of NAA/Cr and Cho/Cr were calculated. The behavior of PD rats in rotarod tests improved, and there were statistical differences in TH-positive cells in SN and TH-positive terminals in striatum after the transplantation of BrdU-labeled MSCs. Transplanted MSCs differentiated into MAP-2-positive neurons. Especially compared with pre-MSC transplantation, the neural metabolite NAA/Cr ratio of the 6-OHDA-injected side of the striatum increased (P < 0.05) and the Cho/Cr ratio decreased (P < 0.05). MSCs transplantation apparently improves neuronal function in the striatum of PD rats.

Augmenting granular activated carbon with natural clay for multicomponent sorption of heavy metals from aqueous solutions.

PubMed

Mu'azu, Nuhu Dalhat; Essa, Mohammed Hussain; Lukman, Salihu

2017-10-01

Multicomponent adsorption of Cd, Cr, Cu, Pb and Zn onto date palm pits based granular activated carbon (GAC) augmented with highly active natural clay at different proportion was investigated. The effects of the initial pH and the adsorbents mixed ratio on the removal selectivity sequence of the metals evaluated. Batch adsorption experiments were undertaken at initial pH 2, 6 and 12. At initial pH 2, both the percent removal and the metals adsorptive capacity decreased with increasing GAC to clay ratio (from 0 to 1) with the percentage removal of Cd, Zn and Cr ions dropping from 68, 81, 100% to 43, 57 and 70%, respectively. At both pH 6 and 12, the percentage removals and adsorption capacities of all the heavy metal ions are higher than at pH 2. Selectivity sequences for pH 2, 6 and 12 followed the order Pb > Cr > Cu > Zn > Cd; Pb > Cr > Cu > Cd > Zn and Cd > Cr > Cu > Pb > Zn, respectively. The adsorption trends were analyzed in relation to point of zero charge and ξ-potential and the metals ions speciation at different pH. These results will help better understand the feasibility of augmenting GAC with natural clay minerals during fixed bed column test which is more beneficial for practical industrial applications.

Modifications to EPA Method 3060A to Improve Extraction of Cr(VI) from Chromium Ore Processing Residue-Contaminated Soils

USGS Publications Warehouse

Mills, Christopher T.; Bern, Carleton R.; Wolf, Ruth E.; Foster, Andrea L.; Morrison, Jean M.; Benzel, William M.

2017-01-01

It has been shown that EPA Method 3060A does not adequately extract Cr(VI) from chromium ore processing residue (COPR). We modified various parameters of EPA 3060A toward understanding the transformation of COPR minerals in the alkaline extraction and improving extraction of Cr(VI) from NIST SRM 2701, a standard COPR-contaminated soil. Aluminum and Si were the major elements dissolved from NIST 2701, and their concentrations in solution were correlated with Cr(VI). The extraction fluid leached additional Al and Si from the method-prescribed borosilicate glass vessels which appeared to suppress the release of Cr(VI). Use of polytetrafluoroethylene vessels and intensive grinding of NIST 2701 increased the amount of Cr(VI) extracted. These modifications, combined with an increased extraction fluid to sample ratio of ≥900 mL g–1 and 48-h extraction time resulted in a maximum release of 1274 ± 7 mg kg–1 Cr(VI). This is greater than the NIST 2701 certified value of 551 ± 35 mg kg–1 but less than 3050 mg kg–1 Cr(VI) previously estimated by X-ray absorption near edge structure spectroscopy. Some of the increased Cr(VI) may have resulted from oxidation of Cr(III) released from brownmillerite which rapidly transformed during the extractions. Layered-double hydroxides remained stable during extractions and represent a potential residence for unextracted Cr(VI).

Pollution control and metal resource recovery for low grade automobile shredder residue: a mechanism, bioavailability and risk assessment.

PubMed

Singh, Jiwan; Lee, Byeong-Kyu

2015-04-01

Automobile shredder residue (ASR) is considered as hazardous waste in Japan and European countries due to presence of heavy metals. This study was carried on the extraction characteristics of heavy metals (Mn, Fe, Ni, and Cr) from automobile shredder residue (ASR). The effects of pH, temperature, particle size, and liquid/solid ratio (L/S) on the extraction of heavy metals were investigated. The recovery rate of Mn, Fe, Ni, and Cr increased with increasing extraction temperature and L/S ratio. The lowest pH 2, the highest L/S ratio, and the smallest particle size showed the highest recovery of heavy metals from ASR. The highest recovery rates were in the following order: Mn > Ni > Cr > Fe. Reduction of mobility factor for the heavy metals was observed in all the size fractions after the recovery. The results of the kinetic analysis for various experimental conditions supported that the reaction rate of the recovery process followed a second order reaction model (R(2) ⩾ 0.95). The high availability of water-soluble fractions of Mn, Fe, Ni, and Cr from the low grade ASR could be potential hazards to the environment. Bioavailability and toxicity risk of heavy metals reduced significantly with pH 2 of distilled water. However, water is a cost-effective extracting agent for the recovery of heavy metals and it could be useful for reducing the toxicity of ASR. Copyright © 2015 Elsevier Ltd. All rights reserved.

Application of a water cooling treatment and its effect on coal-based reduction of high-chromium vanadium and titanium iron ore

NASA Astrophysics Data System (ADS)

Yang, Song-tao; Zhou, Mi; Jiang, Tao; Guan, Shan-fei; Zhang, Wei-jun; Xue, Xiang-xin

2016-12-01

A water cooling treatment was applied in the coal-based reduction of high-chromium vanadium and titanium (V-Ti-Cr) iron ore from the Hongge region of Panzhihua, China. Its effects on the metallization ratio ( η), S removal ratio ( R S), and P removal ratio ( R P) were studied and analyzed on the basis of chemical composition determined via inductively coupled plasma optical emission spectroscopy. The metallic iron particle size and the element distribution of Fe, V, Cr, and Ti in a reduced briquette after water cooling treatment at 1350°C were determined and observed via scanning electron microscopy. The results show that the water cooling treatment improved the η, R S, and R P in the coal-based reduction of V-Ti-Cr iron ore compared to those obtained with a furnace cooling treatment. Meanwhile, the particle size of metallic iron obtained via the water cooling treatment was smaller than that of metallic iron obtained via the furnace cooling treatment; however, the particle size reached 70 μm at 1350°C, which is substantially larger than the minimum particle size required (20 μm) for magnetic separation. Therefore, the water cooling treatment described in this work is a good method for improving the quality of metallic iron in coal-based reduction and it could be applied in the coal-based reduction of V-Ti-Cr iron ore followed by magnetic separation.

HEART: heart exercise and remote technologies: a randomized controlled trial study protocol.

PubMed

Maddison, Ralph; Whittaker, Robyn; Stewart, Ralph; Kerr, Andrew; Jiang, Yannan; Kira, Geoffrey; Carter, Karen H; Pfaeffli, Leila

2011-05-31

Cardiovascular disease (CVD) is the leading cause of death worldwide. Cardiac rehabilitation (CR) is aimed at improving health behaviors to slow or reverse the progression of CVD disease. Exercise is a central element of CR. Technologies such as mobile phones and the Internet (mHealth) offer potential to overcome many of the psychological, physical, and geographical barriers that have been associated with lack of participation in exercise-based CR. We aim to trial the effectiveness of a mobile phone delivered exercise-based CR program to increase exercise capacity and functional outcomes compared with usual CR care in adults with CVD. This paper outlines the rationale and methods of the trial. A single-blinded parallel two-arm randomized controlled trial is being conducted. A total of 170 people will be randomized at 1:1 ratio either to receive a mHealth CR program or usual care. Participants are identified by CR nurses from two metropolitan hospitals in Auckland, New Zealand through outpatient clinics and existing databases. Consenting participants are contacted to attend a baseline assessment. The intervention consists of a theory-based, personalized, automated package of text and video message components via participants' mobile phones and the Internet to increase exercise behavior, delivered over six months. The control group will continue with usual CR. Data collection occurs at baseline and 24 weeks (post-intervention). The primary outcome is change in maximal oxygen uptake from baseline to 24 weeks. Secondary outcomes include post-intervention measures on self-reported physical activity (IPAQ), cardiovascular risk factors (systolic blood pressure, weight, and waist to hip ratio), health related quality of life (SF-36), and cost-effectiveness. This manuscript presents the protocol for a randomized controlled trial of a mHealth exercise-based CR program. Results of this trial will provide much needed information about physical and psychological well-being, and cost-effectiveness of an automated telecommunication intervention. If effective, this intervention has enormous potential to improve the delivery of CR and could easily be scaled up to be delivered nationally (and internationally) in a very short time, enhancing the translational aspect of this research. It also has potential to extend to comprehensive CR (nutrition advice, smoking cessation, medication adherence). ACTRN12611000117910.

N-acetylaspartate, choline, myoinositol, glutamine and glutamate (glx) concentration changes in proton MR spectroscopy (1H MRS) in patients with mild cognitive impairment (MCI).

PubMed

Walecki, Jerzy; Barcikowska, Maria; Ćwikła, Jarosław B; Gabryelewicz, Tomasz

2011-12-01

Purpose of study was evaluation of regional metabolic disorders using 1H MRS in patients with MCI, as a predictor of clinical conversion to dementia based on clinical follow-up. The study group consisted of 31 subjects with diagnosis of MCI based on criteria the Mayo Clinic Group. ¹H MRS was performed with a single-voxel method using PRESS sequence. The volume of interest (VOI) was located in the hippocampal formation and posterior part of the cingulated gyrus. Patients had annual clinical control at least twice. At the beginning, 9 had amnestic MCI and the others had multidomain MCI. During follow-up (median 3 yrs) 8 subjects had stable disease (SD), 13 had disease progression (DP) and 10 develop Alzheimer disease (AD). Baseline metabolic ratios (1H MRS) between 3 groups indicated significant difference (P < 0.05) in left frontal lobe in mI/H20 ratio, between patients with SD (0.27) and DP. In comparing the groups with DP and AD, a significant difference in NAA/Cr (1.77 vs. 1.43) was found. A significant difference within left temporal external lobes was found between SD and DP in NAA/H2O ratio (0.55 vs. 0.51). An additional significant difference within medial temporal lobe was found between DP and AD in Glx/H2O ratio (0.44 vs. 0.34) on the right side. 1H MRS seems to be sensitive method allows prediction of which patients are liable to progress from MCI to AD. Combined with other biomarkers of disease staging, it is an important approach in the preclinical AD diagnosis, as well as the assessment of dementia progression.

Persistent MRD before and after allogeneic BMT predicts relapse in children with acute lymphoblastic leukaemia.

PubMed

Sutton, Rosemary; Shaw, Peter J; Venn, Nicola C; Law, Tamara; Dissanayake, Anuruddhika; Kilo, Tatjana; Haber, Michelle; Norris, Murray D; Fraser, Chris; Alvaro, Frank; Revesz, Tamas; Trahair, Toby N; Dalla-Pozza, Luciano; Marshall, Glenn M; O'Brien, Tracey A

2015-02-01

Minimal residual disease (MRD) during early chemotherapy is a powerful predictor of relapse in acute lymphoblastic leukaemia (ALL) and is used in children to determine eligibility for allogeneic haematopoietic stem cell transplantation (HSCT) in first (CR1) or later complete remission (CR2/CR3). Variables affecting HSCT outcome were analysed in 81 children from the ANZCHOG ALL8 trial. The major cause of treatment failure was relapse, with a cumulative incidence of relapse at 5 years (CIR) of 32% and treatment-related mortality of 8%. Leukaemia-free survival (LFS) and overall survival (OS) were similar for HSCT in CR1 (LFS 62%, OS 83%, n = 41) or CR2/CR3 (LFS 60%, OS 72%, n = 40). Patients achieving bone marrow MRD negativity pre-HSCT had better outcomes (LFS 83%, OS 92%) than those with persistent MRD pre-HSCT (LFS 41%, OS 64%, P < 0·0001) or post-HSCT (LFS 35%, OS 55%, P < 0·0001). Patients with B-other ALL had more relapses (CIR 50%, LFS 41%) than T-ALL and the main precursor-B subtypes including BCR-ABL1, KMT2A (MLL), ETV6-RUNX1 (TEL-AML1) and hyperdiploidy >50. A Cox multivariate regression model for LFS retained both B-other ALL subtype (hazard ratio 4·1, P = 0·0062) and MRD persistence post-HSCT (hazard ratio 3·9, P = 0·0070) as independent adverse prognostic variables. Persistent MRD could be used to direct post-HSCT therapy. © 2014 John Wiley & Sons Ltd.

Serial 1H-MRS in GM2 gangliosidoses.

PubMed

Assadi, Mitra; Baseman, Susan; Janson, Christopher; Wang, Dah-Jyuu; Bilaniuk, Larissa; Leone, Paola

2008-03-01

GM2 gangliosidoses are a group of neuronal storage disorders caused by deficiency in the lysosomal enzyme hexosaminidase A. Clinically, the disease is marked by a relentless encephalopathy. Proton magnetic resonance spectroscopy (1H-MRS) provides in-vivo measurement of various brain metabolites including N-acetyl aspartate+N-acetyl aspartate glutamate (NAA), myo-inositol (mI), choline (Cho) and creatine (Cr). The NAA represents neuronal integrity while elevation in the mI reflects abnormal inflammation and gliosis in the brain tissue. An elevation in the Cho levels suggest cell membrane breakdown and demyelination. We report the clinical and laboratory data in two patients with GM2 gangliosidoses. Serial 1H-MRS evaluations were performed to drive metabolite ratios of NAA/Cr, mI/Cr and Cho/Cr. We acquired the data from four regions of interest (ROI) according to a standard protocol. The results documented a progressive elevation in mI/Cr in all four ROI in patient one and only one ROI (occipital gray matter) in patient 2. We also documented a decline in the NAA/Cr ratios in both cases in most ROI. These results were compared to six age-matched controls and confirmed statistically significant elevation in the mI in our cases. In conclusion, 1H-MRS alterations were suggestive of neuronal loss and inflammation in these patients. 1H-MRS may be a valuable tool in monitoring the disease progress and response to therapy in GM2 gangliosidoses. Elevation in the mI may prove to be more sensitive than the other metabolite alterations.

The bonding, charge distribution, spin ordering, optical, and elastic properties of four MAX phases Cr{sub 2}AX (A = Al or Ge, X = C or N): From density functional theory study

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

Li, Neng, E-mail: lineng@umkc.edu; Department of Physics and Astronomy, University of Missouri-Kansas City, Kansas City, Missouri 64110; Mo, Yuxiang

2013-11-14

In this work, we assess a full spectrum of properties (chemical bonding, charge distribution, spin ordering, optical, and elastic properties) of Cr{sub 2}AC (A = Al, Ge) and their hypothetical nitride counterparts Cr{sub 2}AN (A = Al, Ge) based on density functional theory calculations. The calculated total energy values indicate that a variety of spin ordering of these four compounds depending on interlayer-interactions between M-A and M-X within the sublattice, which is supported by bonding analysis. MAX phase materials are discovered to possess exotic magnetic properties which indicates that these materials could serve as promising candidates for novel layered magnetic materials for various electronicmore » and spintronic applications. Further analysis of optical properties for two polarization vectors of Cr{sub 2}AX shows that the reflectivity is high in the visible-ultraviolet region up to ∼15 eV suggesting Cr{sub 2}AX as a promising candidate for use as a coating material. The elastic coefficients (C{sub ij}) and bulk mechanical properties [bulk modulus (K), shear modulus (G), Young's modulus (E), Poisson's ratio (η), and Pugh ratio (G/K)] of these four Cr{sub 2}AX compounds are also calculated and analyzed, which pave the way to predict or design new MAX phases that are less brittle or tougher by having a lower G/K value or higher η.« less

Plant/soil concentration ratios of SSWRa for contrasting sites around an active U mine-mill

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

Ibrahim, S.A.; Whicker, F.W.

Concentrations of 226Ra were determined in native vegetation and underlying substrate (soil and tailings) at various sites around a conventional open-pit, acid leach U production operation in Wyoming. Plant/soil concentration ratios (CRs) for 226Ra were estimated for various sites, including weathered tailings; a tailings impoundment shoreline; downwind from exposed tailings; a mine overburden reclamation area; and several background locations. Radium-226 concentrations for vegetation and substrate and CR values from the perturbed sites were elevated above background. The highest vegetation concentration (1.3 Bq g-1) was found in a grass which had invaded exposed, weathered tailings. Levels of 226Ra in soil andmore » vegetation and CR values decreased with distance from the tailings impoundment edge. CR values varied significantly among sites, but few differences were found between plant species groups. The observed CR values ranged from 0.07 at the background and reclamation areas to 0.4 downwind from the tailings area. Average CR values for plants growing on exposed tailings and within one meter from the impoundment edge were 0.15 and 0.3, respectively. CR values of 226Ra for plants on tailings substrates were comparatively low in contrast to other radionuclides in the U chain. We speculate that in the case of sulfuric acid leached tailings-derived material, 226Ra is sequestered as sulfate, which is highly insoluble relative to the sulfates of the other elements (e.g., U and Th) resulting in reduced availability for plant uptake.« less

Single voxel proton magnetic resonance spectroscopy in women with and without intimate partner violence-related posttraumatic stress disorder.

PubMed

Seedat, Soraya; Videen, John S; Kennedy, Colleen M; Stein, Murray B

2005-08-30

Preliminary in vivo proton magnetic spectroscopic ((1)H-MRS) studies of N-acetylaspartate (a putative marker of neuronal viability and function) in combat veterans and maltreated children with posttraumatic stress disorder (PTSD) suggest altered neuronal integrity in anterior cingulate and medial temporal lobe structures. In this study, (1)H-MRS was used to measure N-acetylaspartate (NAA), choline (Cho) and myo-inositol (mI) relative to creatine (Cr) in the anterior cingulate of 16 women with histories of intimate partner violence (7 with a DSM-IV diagnosis of PTSD, 9 without PTSD) and 11 healthy, non-abused comparison subjects. The relationship between anterior cingulate chemistry and performance on the Stroop Color-Word task and Part B of the Trail Making Test was also examined. There were no significant differences in anterior cingulate or occipital gray matter metabolite ratios of NAA/Cr and Cho/Cr between intimate partner violence and healthy comparison subjects. Intimate partner violence subjects with PTSD had significantly higher anterior cingulate Cho/Cr than intimate partner violence subjects without PTSD. There was evidence that the subjects with PTSD suffered more severe intimate partner violence as measured by the Conflict Tactics Scale-Revised. Metabolite ratios were not significantly correlated with performance on the Stroop or Trails B. Our findings, in agreement with earlier studies, showed significant alterations in anterior cingulate chemistry in women with PTSD. In contrast to other studies, we found an increase in Cho/Cr rather than a decrease in NAA/Cr, indicating alterations in glia, instead of neuronal dropout.

Metabolic alterations and neurodevelopmental outcome of infants with transposition of the great arteries.

PubMed

Park, I Sook; Yoon, S Young; Min, J Yeon; Kim, Y Hwue; Ko, J Kok; Kim, K Soo; Seo, D Man; Lee, J Hee

2006-01-01

Abnormal neurodevelopment has been reported for infants who were born with transposition of the great arteries (TGA) and underwent arterial switch operation (ASO). This study evaluates the cerebral metabolism of TGA infants at birth and before ASO and neurodevelopment 1 year after ASO. Proton magnetic resonance spectroscopy (1H-MRS) was performed on 16 full-term TGA brains before ASO within 3-6 days after birth. The brain metabolite ratios of [NAA/Cr], [Cho/Cr], and [mI/Cr] evaluated measured. Ten infants were evaluated at 1 year using the Bayley Scales of Infants Development II (BSED II). Cerebral metabolism of infants with TGA was altered in parietal white matter (PWM) and occipital gray matter (OGM) at birth before ASO. One year after ASO, [Cho/Cr] in PWM remained altered, but all metabolic ratios in OGM were normal. The results of BSID II at 1 year showed delayed mental and psychomotor development. This delayed neurodevelopmental outcome may reflect consequences of the altered cerebral metabolism in PWM measured by 1H-MRS. It is speculated that the abnormal hemodynamics due to TGA in utero may be responsible for the impaired cerebral metabolism and the subsequent neurodevelopmental deficit.

Selective and sensitive speciation analysis of Cr(VI) and Cr(III), at sub-μgL-1 levels in water samples by electrothermal atomic absorption spectrometry after electromembrane extraction.

PubMed

Tahmasebi, Zeinab; Davarani, Saied Saeed Hosseiny

2016-12-01

In this work, electromembrane extraction in combination with electrothermal atomic absorption spectrometry (ET-AAS) was investigated for speciation, preconcentration and quantification of Cr(VI) and Cr(III) in water samples through the selective complexation of Cr(VI) with 1,5-diphenylcarbazide (DPC) as a complexing agent. DPC reduces Cr(VI) to Cr(III) ions and then Cr(III) species are extracted based on electrokinetic migration of their cationic complex (Cr(III)-DPC) toward the negative electrode placed in the hollow fiber. Also, once oxidized to Cr(VI), Cr(III) ions in initial sample were determined by this procedure. The influence of extraction parameters such as pH, type of organic solvent, chelating agent concentration, stirring rate, extraction time and applied voltage were evaluated following a one-at-a-time optimization approach. Under optimized conditions, the extracted analyte was quantified by ETAAS, with an acceptable linearity in the range of 0.05-5ngmL -1 (R 2 value=0.996), and a repeatability (%RSD) between 3.7% and 12.2% (n=4) for 5.0 and 1.0ngmL -1 of Cr(VI), respectively. Also, we obtained an enrichment factor of 110 that corresponded to the recovery of 66%. The detection limit (S/N ratio of 3:1) was 0.02ngmL -1 . Finally, this new method was successfully employed to determine Cr(III) and Cr(VI) species in real water samples. Copyright © 2016. Published by Elsevier B.V.

Pediatric Asthma Mortality and Hospitalization Trends Across Asia Pacific Relationship With Asthma Drug Utilization Patterns

PubMed Central

2009-01-01

Background The wide variability in prevalence of childhood asthma across Asia Pacific is well documented, but less is known about its trends in mortality and hospitalization. Objectives To examine pediatric asthma mortality and hospitalization trends of selected countries across Asia Pacific, and also patterns of asthma drug utilization. Materials and Methods Mortality and population data were sourced from the World Health Organization's mortality database. Data on hospitalization were obtained by direct inquiry and from government and scientific publications. Drug use for asthma was expressed as a controller-to-reliever (C:R) ratio (ie, units of inhaled corticosteroids/units of short-acting β-agonists, sold in each country). Time-series regression analyses were used to examine temporal patterns and study association between deaths, hospitalizations, and drug use. Results Japan showed a decreasing trend in pediatric asthma mortality whereas an increase was observed in Thailand. Hospitalizations decreased in Australia and Singapore but increased in Taiwan, Republic of China. C:R ratios increased significantly across the countries. Conclusions Mixed trends in pediatric asthma mortality and hospitalization rates were observed, which coincided with a uniform increase in C:R ratios. This may reflect importance of other aspects of asthma management besides pharmacotherapy. PMID:23283014

Preconception Maternal Iodine Status Is Positively Associated with IQ but Not with Measures of Executive Function in Childhood

PubMed Central

Robinson, Sian M; Crozier, Sarah R; Miles, Elizabeth A; Gale, Catharine R; Calder, Philip C; Cooper, Cyrus; Inskip, Hazel M; Godfrey, Keith M

2018-01-01

Abstract Background Adverse effects of severe maternal iodine deficiency in pregnancy on fetal brain development are well-established, but the effects of milder deficiency are uncertain. Most studies examine iodine status in pregnancy; less is known about iodine nutrition before conception. Objective We examined relations between maternal preconception iodine status and offspring cognitive function, within a prospective mother-offspring cohort. Methods Maternal iodine status was assessed through the use of the ratio of iodine:creatinine concentrations (I/Cr) in spot urine samples [median (IQR) period before conception 3.3 y (2.2–4.7 y)]. Childhood cognitive function was assessed at age 6–7 y. Full-scale IQ was assessed via the Wechsler Abbreviated Scale of Intelligence, and executive function through the use of tests from the Cambridge Neuropsychological Test Automated Battery (CANTAB). Analyses (n = 654 mother-child dyads) were adjusted for potential confounders including maternal intelligence, education, and breastfeeding duration. Results The median (IQR) urinary iodine concentration was 108.4 µg/L (62.2–167.8 µg/L) and the I/Cr ratio 114 µg/g (76–164 µg/g). The preconception I/Cr ratio was positively associated with child IQ, before and after adjustment for potential confounding influences [β = 0.13 (95% CI: 0.04, 0.21)/SD, P = 0.003]. 8.9% of women had a preconception urinary I/Cr ratio <50 µg/g; compared with those with an I/Cr ratio ≥150 µg/g, the IQ of their offspring was 0.49 (95% CI: 0.79, 0.18) SD lower. There were no associations with the executive function outcomes assessed via CANTAB, before or after adjustment for confounders. Conclusion The positive association between iodine status before conception and child IQ provides some support for demonstrated links between low maternal iodine status in pregnancy and poorer cognitive function reported in other studies. However, given the negative effects on school performance previously observed in children born to iodine-deficient mothers, the lack of associations with measures of executive function in the present study was unexpected. Further data are needed to establish the public health importance of low preconception iodine status. PMID:29767745

Evaluation of [¹⁸F]PFH PET renography to predict future disease progression in a rat model of autosomal dominant polycystic kidney disease.

PubMed

Pathuri, Gopal; Hedrick, Andria F; Awasthi, Vibhudutta; Cowley, Benjamin D; Gali, Hariprasad

2016-01-01

Prognostic markers for progression of polycystic kidney disease (PKD) are limited. We evaluated the potential of early para-[(18)F]fluorohippurate ([(18)F]PFH) positron emission tomography (PET) renography to predict future progression of PKD in Han:SPRD rats with slowly progressive autosomal dominant PKD. Male and female heterozygous (Cy/+) and normal littermate (+/+) Han:SPRD rats underwent [(18)F]PFH PET renography and blood sampling to measure serum creatinine (S-Cr) and serum urea nitrogen (SUN) concentrations at 6 and 26 wk of age. T2 and T20 values, which represent the percent of the injected dose of [(18)F]PFH in kidneys at 2 and 20 min after injection, were determined from imaging data. T20/T2 ratio was assessed as a prognostic marker. Rats were euthanized after renography at 26 wk of age, and kidney weight/body weight ratios (KW/BW%) were determined as a measure of PKD progression. Male and female Cy/+ rats are known to manifest PKD of different severity, male Cy/+ rats display much more severe PKD than female rats. S-Cr and SUN concentrations did not differ between +/+ and Cy/+ rats and between female and male Cy/+ rats at 6 wk of age, but they were higher at 26 wk of age and male rats displayed higher values than female rats, which indicates inability of S-Cr and SUN to measure disease severity at an early stage. T20/T2 ratios were higher for Cy/+ than +/+ rats at 6 wk of age. Importantly, male Cy/+ rats displayed higher T20/T2 ratios than female Cy/+ rats. T20/T2 ratios obtained at 6 wk of age correlated well with S-Cr, SUN, and KW/BW% values obtained at 26 wk of age. This study indicates that T20/T2 ratio derived from [(18)F]PFH PET renography at an early age could be useful as a novel prognostic marker to predict future disease severity in a rat model of ADPKD. Copyright © 2015 Elsevier Inc. All rights reserved.

Mineralogical determination and geo-chemical modeling of chromium release from AOD slag: Distribution and leachability aspects.

PubMed

Li, Junguo; Liu, Bao; Zeng, Yanan; Wang, Ziming

2017-01-01

AOD (argon oxygen decarburization) slag, which is the by-product of the stainless steel refining process, is a recyclable slag because of its high content of calcium and silicon. The leaching toxicity cannot be ignored in the recycling process because the slag contains a certain amount of Cr. In this study, the mineral analysis, batch leaching tests and thermodynamic and kinetic modeling by PHREEQC combined with FactSage software were performed to explore the influence of the dissolution of primary minerals and the precipitation of secondary minerals on the elution of Cr from AOD slag. The results indicated that the main minerals in the original AOD slag are larnite, merwinite, pyroxene and periclase. Cr was dispersed in the mineral phases mentioned above. The simulation of Cr leaching controlled by Cr(III)-hydroxide corresponded better to the batch leaching tests, while the Cr leaching controlled by chromite or double control was underestimated. Increasing the L/S ratio enhances the pH of the leachate and restrains the elution of Cr from the AOD slag. Copyright © 2016 Elsevier Ltd. All rights reserved.

Nitrification inhibition by hexavalent chromium Cr(VI)--Microbial ecology, gene expression and off-gas emissions.

PubMed

Kim, Young Mo; Park, Hongkeun; Chandran, Kartik

2016-04-01

The goal of this study was to investigate the responses in the physiology, microbial ecology and gene expression of nitrifying bacteria to imposition of and recovery from Cr(VI) loading in a lab-scale nitrification bioreactor. Exposure to Cr(VI) in the reactor strongly inhibited nitrification performance resulting in a parallel decrease in nitrate production and ammonia consumption. Cr(VI) exposure also led to an overall decrease in total bacterial concentrations in the reactor. However, the fraction of ammonia oxidizing bacteria (AOB) decreased to a greater extent than the fraction of nitrite oxidizing bacteria (NOB). In terms of functional gene expression, a rapid decrease in the transcript concentrations of amoA gene coding for ammonia oxidation in AOB was observed in response to the Cr(VI) shock. In contrast, transcript concentrations of the nxrA gene coding for nitrite oxidation in NOB were relatively unchanged compared to Cr(VI) pre-exposure levels. Therefore, Cr(VI) exposure selectively and directly inhibited activity of AOB, which indirectly resulted in substrate (nitrite) limitation to NOB. Significantly, trends in amoA expression preceded performance trends both during imposition of and recovery from inhibition. During recovery from the Cr(VI) shock, the high ammonia concentrations in the bioreactor resulted in an irreversible shift towards AOB populations, which are expected to be more competitive in high ammonia environments. An inadvertent impact during recovery was increased emission of nitrous oxide (N2O) and nitric oxide (NO), consistent with recent findings linking AOB activity and the production of these gases. Therefore, Cr(VI) exposure elicited multiple responses on the microbial ecology, gene expression and both aqueous and gaseous nitrogenous conversion in a nitrification process. A complementary interrogation of these multiple responses facilitated an understanding of both direct and indirect inhibitory impacts on nitrification. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chromium in rivers impacted by tannery wastes determined by high performance liquid chromatography - inductively coupled plasma mass spectrometry

NASA Astrophysics Data System (ADS)

Pereira de Abreu, M.-H.; Vignati, D.; Dominik, J.

2003-05-01

The total chromium concentrations by ICP-MS and HPLC-ICP-MS and the redox chromium species have been determined in rivers impacted by untreated wastes from tanneries at Fès (Morocco). The results obtained by two ICP-MS analysis methods showed significantly different chromium values at m/z 53. The higher values obtained with external calibration, can be attributed to matrix effects, especially ^{37}Cl ^{16}O at m/z 53. This is confirmed on the chromatograms by the presence of a peak at 100s with the anomalous ^{52}Cr/^{53}Cr isotopic ratio. The hexavalent chromium was not detected. Two trivalent chromium monomer species, Cr(OH)(H2O)5^{2+} and Cr(H2O)6^{3+}, were present in low concentrations. We suppose that the major part of chromium occurred as Cr(III) polymeric species which were not retained on the column. These Cr(III) forms are usually complexed with Cl^- or/and SO4^{2-}, used as tanning agents.

Dietary Supplementation with Pioglitazone Hydrochloride and Chromium Methionine Improves Growth Performance, Meat Quality, and Antioxidant Ability in Finishing Pigs.

PubMed

Jin, Cheng-Long; Wang, Qiang; Zhang, Zong-Ming; Xu, Yin-Long; Yan, Hui-Chao; Li, Hai-Chang; Gao, Chun-Qi; Wang, Xiu-Qi

2018-05-02

This work was designed to investigate the synergistic effects of pioglitazone hydrochloride (PGZ) and chromium methionine (CrMet) on meat quality, muscle fatty acid profile, and antioxidant ability of pigs. Pigs in four groups were fed a basic diet or basic diet supplemented with 15 mg/kg of PGZ, 200 μg/kg of CrMet, or 15 mg/kg of PGZ + 200 μg/kg of CrMet. In comparison to the control group, the average daily feed intake, feed/gain ratio, and serum high-density lipoprotein level decreased in the PGZ + CrMet group. Dietary PGZ + CrMet supplementation increased carcass dressing percentage, intramuscular fat, and marbling score. The percentages of C18:1ω-9c, C18:2ω-6c, C18:3ω-3, and polyunsaturated fatty acid (PUFA) in the longissimus thoracis muscle were increased in the PGZ + CrMet group. Greater superoxide dismutase and glutathione peroxidase activities were observed in the PGZ + CrMet group compared to the control group. Collectively, these findings suggested that feed with PGZ and CrMet improved the growth performance and meat quality, especially for PUFA proportions and antioxidant ability.

Recent progress in the development of carbonate-intercalated Zn/Cr LDH as a novel photocatalyst for hydrogen evolution aimed at the utilization of solar light.

PubMed

Parida, Kulamani; Mohapatra, Lagnamayee

2012-01-28

A series of novel photocatalysts Zn/Cr LDH with different Zn/Cr molar ratios (2 : 1, 3 : 1, 4 : 1 and 2 : 1-CO(3)) were fabricated by a co-precipitation method and evaluated for photodecomposition of water using visible light irradiation. Various characterization methods were employed to investigate the structures, morphologies and photocatalytic properties. In comparison to Zn/Cr (2 : 1) LDH, Zn/Cr-CO(3) (2 : 1) LDH extends the absorption edges to the visible region and exhibits good photocatalytic activity, even without the assistance of co-catalysts. The visible light photocatalytic activity is ascribed to the charge transfer spectra of octahedral Cr ions in LDH. Zn/Cr-CO(3) LDH shows enhanced photocatalytic activities compared to Zn/Cr LDH as carbonate ions oxidise by holes to form carbonate radicals, inhibit the rapid recombination of e(-) and h(+) charge carriers and thereby suppress the backward reaction to some extent. This work provides a detailed understanding of the semiconductor properties of LDHs for photocatalytical hydrogen evolution.

Power and efficiency scaling of diode pumped Cr:LiSAF lasers: 770-1110 nm tuning range and frequency doubling to 387-463 nm.

PubMed

Demirbas, Umit; Baali, Ilyes

2015-10-15

We report significant average power and efficiency scaling of diode-pumped Cr:LiSAF lasers in continuous-wave (cw), cw frequency-doubled, and mode-locked regimes. Four single-emitter broad-area laser diodes around 660 nm were used as the pump source, which provided a total pump power of 7.2 W. To minimize thermal effects, a 20 mm long Cr:LiSAF sample with a relatively low Cr-concentration (0.8%) was used as the gain medium. In cw laser experiments, 2.4 W of output power, a slope efficiency of 50%, and a tuning range covering the 770-1110 nm region were achieved. Intracavity frequency doubling with beta-barium borate (BBO) crystals generated up to 1160 mW of blue power and a record tuning range in the 387-463 nm region. When mode locked with a saturable absorber mirror, the laser produced 195 fs pulses with 580 mW of average power around 820 nm at a 100.3 MHz repetition rate. The optical-to-optical conversion efficiency of the system was 33% in cw, 16% in cw frequency-doubled, and 8% in cw mode-locked regimes.

Phosphines bearing alkyne substituents: synthesis and hydrophosphination polymerization.

PubMed

Greenberg, Sharonna; Stephan, Douglas W

2009-09-07

A synthetic route is described for a series of phosphines bearing pendant alkyne substituents, from the conversion of BrC(6)H(2)R(2)C[triple bond]CR' (R = Me, i-Pr; R' = Ph, SiMe(3)) to [(mu-Br)Cu(Et(2)N)(2)PC(6)H(2)R(2)C[triple bond]CR'](2) and subsequently to Cl(2)PC(6)H(2)R(2)C[triple bond]CR' and H(2)PC(6)H(2)R(2)C[triple bond]CR'. Lithiation and subsequent alkylation yield the secondary phosphines R(H)PC(6)H(2)(i-Pr)(2)C[triple bond]CPh (R = CH(2)i-Pr, CH(2)Ph). Intermolecular hydrophosphination-polymerization is used to prepare the polymeric species [RPC(6)H(2)(i-Pr)(2)CH=CPh](n), which can then be sulfurized to give [RP(S)C(6)H(2)(i-Pr)(2)CH=CPh](n). The polymeric products were characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and gel permeation chromatography. These data indicate a degree of polymerization (DP(n)) of up to 60. Discussion of the mechanism is augmented with gas-phase density functional theory calculations.

CO2-induced pH reduction increases physiological toxicity of nano-TiO2 in the mussel Mytilus coruscus

PubMed Central

Hu, Menghong; Lin, Daohui; Shang, Yueyong; Hu, Yi; Lu, Weiqun; Huang, Xizhi; Ning, Ke; Chen, Yimin; Wang, Youji

2017-01-01

The increasing usage of nanoparticles has caused their considerable release into the aquatic environment. Meanwhile, anthropogenic CO2 emissions have caused a reduction of seawater pH. However, their combined effects on marine species have not been experimentally evaluated. This study estimated the physiological toxicity of nano-TiO2 in the mussel Mytilus coruscus under high pCO2 (2500–2600 μatm). We found that respiration rate (RR), food absorption efficiency (AE), clearance rate (CR), scope for growth (SFG) and O:N ratio were significantly reduced by nano-TiO2, whereas faecal organic weight rate and ammonia excretion rate (ER) were increased under nano-TiO2 conditions. High pCO2 exerted lower effects on CR, RR, ER and O:N ratio than nano-TiO2. Despite this, significant interactions of CO2-induced pH change and nano-TiO2 were found in RR, ER and O:N ratio. PCA showed close relationships among most test parameters, i.e., RR, CR, AE, SFG and O:N ratio. The normal physiological responses were strongly correlated to a positive SFG with normal pH and no/low nano-TiO2 conditions. Our results indicate that physiological functions of M. coruscus are more severely impaired by the combination of nano-TiO2 and high pCO2. PMID:28054631

CO2-induced pH reduction increases physiological toxicity of nano-TiO2 in the mussel Mytilus coruscus

NASA Astrophysics Data System (ADS)

Hu, Menghong; Lin, Daohui; Shang, Yueyong; Hu, Yi; Lu, Weiqun; Huang, Xizhi; Ning, Ke; Chen, Yimin; Wang, Youji

2017-01-01

The increasing usage of nanoparticles has caused their considerable release into the aquatic environment. Meanwhile, anthropogenic CO2 emissions have caused a reduction of seawater pH. However, their combined effects on marine species have not been experimentally evaluated. This study estimated the physiological toxicity of nano-TiO2 in the mussel Mytilus coruscus under high pCO2 (2500-2600 μatm). We found that respiration rate (RR), food absorption efficiency (AE), clearance rate (CR), scope for growth (SFG) and O:N ratio were significantly reduced by nano-TiO2, whereas faecal organic weight rate and ammonia excretion rate (ER) were increased under nano-TiO2 conditions. High pCO2 exerted lower effects on CR, RR, ER and O:N ratio than nano-TiO2. Despite this, significant interactions of CO2-induced pH change and nano-TiO2 were found in RR, ER and O:N ratio. PCA showed close relationships among most test parameters, i.e., RR, CR, AE, SFG and O:N ratio. The normal physiological responses were strongly correlated to a positive SFG with normal pH and no/low nano-TiO2 conditions. Our results indicate that physiological functions of M. coruscus are more severely impaired by the combination of nano-TiO2 and high pCO2.