Science.gov

Sample records for 1h t1 values

  1. Hematocrit and oxygenation dependence of blood (1)H(2)O T(1) at 7 Tesla.

    PubMed

    Grgac, Ksenija; van Zijl, Peter C M; Qin, Qin

    2013-10-01

    Knowledge of blood (1)H2O T1 is critical for perfusion-based quantification experiments such as arterial spin labeling and cerebral blood volume-weighted MRI using vascular space occupancy. The dependence of blood (1)H2O T1 on hematocrit fraction (Hct) and oxygen saturation fraction (Y) was determined at 7 T using in vitro bovine blood in a circulating system under physiological conditions. Blood (1)H2O R1 values for different conditions could be readily fitted using a two-compartment (erythrocyte and plasma) model, which are described by a monoexponential longitudinal relaxation rate constant dependence. It was found that T1 = 2171 ± 39 ms for Y = 1 (arterial blood) and 2010 ± 41 ms for Y = 0.6 (venous blood), for a typical Hct of 0.42. The blood (1)H2O T1 values in the normal physiological range (Hct from 0.35 to 0.45, and Y from 0.6 to 1.0) were determined to range from 1900 to 2300 ms. The influence of oxygen partial pressure (pO2) and the effect of plasma osmolality for different anticoagulants were also investigated. It is discussed why blood (1)H2O T1 values measured in vivo for human blood may be about 10-20% larger than found in vitro for bovine blood at the same field strength. PMID:23169066

  2. 14N quadrupole resonance and 1H T1 dispersion in the explosive RDX.

    PubMed

    Smith, John A S; Blanz, Martin; Rayner, Timothy J; Rowe, Michael D; Bedford, Simon; Althoefer, Kaspar

    2011-12-01

    The explosive hexahydro-1,3,5-trinitro-s-triazine (CH2-N-NO2)3, commonly known as RDX, has been studied by 14N NQR and 1H NMR. NQR frequencies and relaxation times for the three ν+ and ν- lines of the ring 14N nuclei have been measured over the temperature range 230-330 K. The 1H NMR T1 dispersion has been measured for magnetic fields corresponding to the 1H NMR frequency range of 0-5.4 M Hz. The results have been interpreted as due to hindered rotation of the NO2 group about the N-NO2 bond with an activation energy close to 92 kJ mol(-1). Three dips in the 1H NMR dispersion near 120, 390 and 510 kHz are assigned to the ν0, ν- and ν+ transitions of the 14NO2 group. The temperature dependence of the inverse line-width parameters T2∗ of the three ν+ and ν- ring nitrogen transitions between 230 and 320 K can be explained by a distribution in the torsional oscillational amplitudes of the NO2 group about the N-NO2 bond at crystal defects whose values are consistent with the latter being mainly edge dislocations or impurities in the samples studied. Above 310 K, the 14N line widths are dominated by the rapid decrease in the spin-spin relaxation time T2 due to hindered rotation of the NO2 group. A consequence of this is that above this temperature, the 1H T1 values at the quadrupole dips are dominated by the spin mixing time between the 1H Zeeman levels and the combined 1H and 14N spin-spin levels. PMID:21978662

  3. Correlation between 1H FID and T1rho components in heterogeneous polymer systems: an application to SBS.

    PubMed

    Ferrini, V; Forte, C; Geppi, M; Pizzanelli, S; Veracini, C A

    2005-06-01

    Wideline 1H FID and relaxation measurements of a relatively simple motionally heterogeneous system, the triblock copolymer styrene-butadiene-styrene, have been performed in a temperature range between the polystyrene and polybutadiene glass transition temperatures. The two FID and the two spin lattice relaxation time in the rotating frame (T1rho) components found at each temperature have been correlated by means of a two-dimensional approach. It is shown that this approach allows dynamic information, not accessible simply by interpreting proton T1 and T1rho data, to be revealed. In the case examined, the correlation found could be confirmed by high-resolution 1H T1rho-selective 13C Cross Polarization experiments. PMID:15799878

  4. Analysis of amorphous solid dispersions using 2D solid-state NMR and (1)H T(1) relaxation measurements.

    PubMed

    Pham, Tran N; Watson, Simon A; Edwards, Andrew J; Chavda, Manisha; Clawson, Jacalyn S; Strohmeier, Mark; Vogt, Frederick G

    2010-10-01

    Solid-state NMR (SSNMR) can provide detailed structural information about amorphous solid dispersions of pharmaceutical small molecules. In this study, the ability of SSNMR experiments based on dipolar correlation, spin diffusion, and relaxation measurements to characterize the structure of solid dispersions is explored. Observation of spin diffusion effects using the 2D (1)H-(13)C cross-polarization heteronuclear correlation (CP-HETCOR) experiment is shown to be a useful probe of association between the amorphous drug and polymer that is capable of directly proving glass solution formation. Dispersions of acetaminophen and indomethacin in different polymers are examined using this approach, as well as (1)H double-quantum correlation experiments to probe additional structural features. (1)H-(19)F CP-HETCOR serves a similar role for fluorinated drug molecules such as diflunisal in dispersions, providing a rapid means to prove the formation of a glass solution. Phase separation is detected using (13)C, (19)F, and (23)Na-detected (1)H T(1) experiments in crystalline and amorphous solid dispersions that contain small domains. (1)H T(1) measurements of amorphous nanosuspensions of trehalose and dextran illustrate the ability of SSNMR to detect domain size effects in dispersions that are not glass solutions via spin diffusion effects. Two previously unreported amorphous solid dispersions involving up to three components and containing voriconazole and telithromycin are analyzed using these experiments to demonstrate the general applicability of the approach. PMID:20681586

  5. Measurement of T1/T2 relaxation times in overlapped regions from homodecoupled 1H singlet signals

    NASA Astrophysics Data System (ADS)

    Castañar, Laura; Nolis, Pau; Virgili, Albert; Parella, Teodor

    2014-07-01

    The implementation of the HOmodecoupled Band-Selective (HOBS) technique in the conventional Inversion-Recovery and CPMG-based PROJECT experiments is described. The achievement of fully homodecoupled signals allows the distinction of overlapped 1H resonances with small chemical shift differences. It is shown that the corresponding T1 and T2 relaxation times can be individually measured from the resulting singlet lines using conventional exponential curve-fitting methods.

  6. Removal of t1 noise from metabolomic 2D 1H- 13C HSQC NMR spectra by Correlated Trace Denoising

    NASA Astrophysics Data System (ADS)

    Poulding, Simon; Charlton, Adrian J.; Donarski, James; Wilson, Julie C.

    2007-12-01

    The presence of t1 noise artefacts in 2D phase-cycled Heteronuclear Single Quantum Coherence (HSQC) spectra constrains the use of this experiment despite its superior sensitivity. This paper proposes a new processing algorithm, working in the frequency-domain, for reducing t1 noise. The algorithm has been developed for use in contexts, such as metabolomic studies, where existing denoising techniques cannot always be applied. Two test cases are presented that show the algorithm to be effective in improving the SNR of peaks embedded within t1 noise by a factor of more than 2, while retaining the intensity and shape of genuine peaks.

  7. Prefrontal NAA and Glx Levels in Different Stages of Psychotic Disorders: a 3T 1H-MRS Study.

    PubMed

    Liemburg, Edith; Sibeijn-Kuiper, Anita; Bais, Leonie; Pijnenborg, Gerdina; Knegtering, Henderikus; van der Velde, Jorien; Opmeer, Esther; de Vos, Annerieke; Dlabac-De Lange, Jozarni; Wunderink, Lex; Aleman, André

    2016-01-01

    H-Magnetic Resonance Spectroscopy ((1)H-MRS) can offer insights in various neuropathologies by measuring metabolite levels in the brain. In the current study we investigated the levels of glutamate + glutamine (Glx, neurotransmitter and precursor) and N-Acetyl Aspartate + glutamic acid (NAA + NAAG; neuronal viability) in the prefrontal cortex of patients with a psychotic disorder and people at Ultra High Risk (UHR) for psychosis. A (1)H-MRS spectrum was acquired in 31 patients with a recent onset psychotic disorder and 60 with a chronic state, 16 UHR patients and 36 healthy controls. Absolute metabolite levels were calculated using LCModel with a reference water peak. Groups were compared while taking into account age and partial volume effects. Moreover, we investigated associations with positive and negative symptoms, duration of illness, and antipsychotic treatment in patients. The most notable finding is that chronicity of schizophrenia was related to decreased levels of Glx and NAA. On the other hand, although on an exploratory note, UHR showed increased levels of prefrontal Glx and NAA levels with increasing age. Our results may indicate an initial Glx and NAA increase and subsequent decrease during illness progression that may be related to the neurotoxic effects of glutamate. PMID:26903078

  8. Prefrontal NAA and Glx Levels in Different Stages of Psychotic Disorders: a 3T 1H-MRS Study

    PubMed Central

    Liemburg, Edith; Sibeijn-Kuiper, Anita; Bais, Leonie; Pijnenborg, Gerdina; Knegtering, Henderikus; van der Velde, Jorien; Opmeer, Esther; de Vos, Annerieke; Dlabac-De Lange, Jozarni; Wunderink, Lex; Aleman, André

    2016-01-01

    H-Magnetic Resonance Spectroscopy (1H-MRS) can offer insights in various neuropathologies by measuring metabolite levels in the brain. In the current study we investigated the levels of glutamate + glutamine (Glx, neurotransmitter and precursor) and N-Acetyl Aspartate + glutamic acid (NAA + NAAG; neuronal viability) in the prefrontal cortex of patients with a psychotic disorder and people at Ultra High Risk (UHR) for psychosis. A 1H-MRS spectrum was acquired in 31 patients with a recent onset psychotic disorder and 60 with a chronic state, 16 UHR patients and 36 healthy controls. Absolute metabolite levels were calculated using LCModel with a reference water peak. Groups were compared while taking into account age and partial volume effects. Moreover, we investigated associations with positive and negative symptoms, duration of illness, and antipsychotic treatment in patients. The most notable finding is that chronicity of schizophrenia was related to decreased levels of Glx and NAA. On the other hand, although on an exploratory note, UHR showed increased levels of prefrontal Glx and NAA levels with increasing age. Our results may indicate an initial Glx and NAA increase and subsequent decrease during illness progression that may be related to the neurotoxic effects of glutamate. PMID:26903078

  9. Osmotic and aging effects in caviar oocytes throughout water and lipid changes assessed by 1H NMR T1 and T2 relaxation and MRI.

    PubMed

    Gussoni, Maristella; Greco, Fulvia; Vezzoli, Alessandra; Paleari, Maria Antonietta; Moretti, Vittorio Maria; Lanza, Barbara; Zetta, Lucia

    2007-01-01

    By combining NMR relaxation spectroscopy and magnetic resonance imaging techniques, unsalted (us) and salted (s) caviar (Acipenser transmontanus) oocytes were characterized over a storage period of up to 90 days. The aging and the salting effects on the two major cell constituents, water and lipids, were separately assessed. T1 and T2 decays were interpreted by assuming a two-site exchange model. At Day 0, two water compartments that were not in fast exchange were identified by the T1 relaxation measurements on the us oocytes. In the s samples, T1 decay was monoexponential. During the time of storage, an increment of the free water amount was found for the us oocytes, ascribed to an increased metabolism. T1 and T2 of the s oocytes shortened as a consequence of the osmotic stress produced by salting. Selective images showed the presence of water endowed with different regional mobility that severely changed during the storage. Lipid T1 relaxation decays collected on us and s samples were found to be biexponential, and the T1 values lengthened during storage. In us and s oocytes, the increased lipid mobility with the storage was ascribed to lipolysis. Selective images of us samples showed lipids that were confined to the cytoplasm for up to 60 days of storage. PMID:17222723

  10. The natural degeneration course in the T1rho values of normal knee cartilage.

    PubMed

    Goto, Hajimu; Iwama, Yuki; Fujii, Masahiko; Aoyama, Nobukazu; Kubo, Seiji; Kuroda, Ryosuke; Ohno, Yoshiharu; Sugimura, Kazuro

    2011-01-01

    The purpose of our study is to investigate whether there is an age-related change in T1 rho values and to evaluate the effects of weight bearing on age-related increase in T1 rho values of normal cartilage. Thirty-two asymptomatic patients were examined using a 3.0T MRI to determine knee cartilage T1 rho values. Femorotibial and patella cartilage was defined as weight-bearing cartilage (WB-C) and non-weight-bearing cartilage (NWB-C), respectively. The femoral cartilage was divided into weight-bearing (WB-P) and less-weight-bearing (LWB-P) portions. Pearson's correlation coefficient and single regression analysis were used to assess the relationship between cartilage T1 rho values and age. The slopes of the regression lines of cartilage T1 rho values and age were compared between WB-C and NWB-C and between WB-P and LWB-P. Cartilage T1 rho values correlated positively with aging for all cartilage regions and all age groups (p<0.001). In the medial femoral cartilage, the age-related increase in T1 rho values was significantly greater for WB-P than for NWB-P (p<0.05). For several cartilage regions, this increase was greater for WB-C than for LWB-C (p<0.05). The T1 rho value is very sensitive to age-related cartilage degeneration and weight bearing-related degeneration, and hence may be a very sensitive and useful measure for the early diagnosis of osteoarthritis. PMID:22971986

  11. High-field 1H T1 and T2 NMR relaxation time measurements of H2O in homeopathic preparations of quartz, sulfur, and copper sulfate

    NASA Astrophysics Data System (ADS)

    Baumgartner, Stephan; Wolf, Martin; Skrabal, Peter; Bangerter, Felix; Heusser, Peter; Thurneysen, André; Wolf, Ursula

    2009-09-01

    Quantitative meta-analyses of randomized clinical trials investigating the specific therapeutic efficacy of homeopathic remedies yielded statistically significant differences compared to placebo. Since the remedies used contained mostly only very low concentrations of pharmacologically active compounds, these effects cannot be accounted for within the framework of current pharmacology. Theories to explain clinical effects of homeopathic remedies are partially based upon changes in diluent structure. To investigate the latter, we measured for the first time high-field (600/500 MHz) 1H T1 and T2 nuclear magnetic resonance relaxation times of H2O in homeopathic preparations with concurrent contamination control by inductively coupled plasma mass spectrometry (ICP-MS). Homeopathic preparations of quartz (10 c-30 c, n = 21, corresponding to iterative dilutions of 100-10-100-30), sulfur (13 x-30 x, n = 18, 10-13-10-30), and copper sulfate (11 c-30 c, n = 20, 100-11-100-30) were compared to n = 10 independent controls each (analogously agitated dilution medium) in randomized and blinded experiments. In none of the samples, the concentration of any element analyzed by ICP-MS exceeded 10 ppb. In the first measurement series (600 MHz), there was a significant increase in T1 for all samples as a function of time, and there were no significant differences between homeopathic potencies and controls. In the second measurement series (500 MHz) 1 year after preparation, we observed statistically significant increased T1 relaxation times for homeopathic sulfur preparations compared to controls. Fifteen out of 18 correlations between sample triplicates were higher for controls than for homeopathic preparations. No conclusive explanation for these phenomena can be given at present. Possible hypotheses involve differential leaching from the measurement vessel walls or a change in water molecule dynamics, i.e., in rotational correlation time and/or diffusion. Homeopathic preparations

  12. Ventricular cerebrospinal fluid lactate is increased in chronic fatigue syndrome compared with generalized anxiety disorder: an in vivo 3.0 T (1)H MRS imaging study.

    PubMed

    Mathew, Sanjay J; Mao, Xiangling; Keegan, Kathryn A; Levine, Susan M; Smith, Eric L P; Heier, Linda A; Otcheretko, Viktor; Coplan, Jeremy D; Shungu, Dikoma C

    2009-04-01

    Chronic fatigue syndrome (CFS) is a controversial diagnosis because of the lack of biomarkers for the illness and its symptom overlap with neuropsychiatric, infectious, and rheumatological disorders. We compared lateral ventricular volumes derived from tissue-segmented T(1)-weighted volumetric MRI data and cerebrospinal fluid (CSF) lactate concentrations measured by proton MRS imaging ((1)H MRSI) in 16 subjects with CFS (modified US Centers for Disease Control and Prevention criteria) with those in 14 patients with generalized anxiety disorder (GAD) and in 15 healthy volunteers, matched group-wise for age, sex, body mass index, handedness, and IQ. Mean lateral ventricular lactate concentrations measured by (1)H MRSI in CFS were increased by 297% compared with those in GAD (P < 0.001) and by 348% compared with those in healthy volunteers (P < 0.001), even after controlling for ventricular volume, which did not differ significantly between the groups. Regression analysis revealed that diagnosis accounted for 43% of the variance in ventricular lactate. CFS is associated with significantly raised concentrations of ventricular lactate, potentially consistent with recent evidence of decreased cortical blood flow, secondary mitochondrial dysfunction, and/or oxidative stress abnormalities in the disorder. PMID:18942064

  13. Mirnov Coil Analysis by Singular Value Decomposition Method in IR-T1 Tokamak

    NASA Astrophysics Data System (ADS)

    Salemi, Mohammad K.; Saadat, Shervin; Ghoranneviss, Mahmoud; Tabadar, Alireza

    2010-10-01

    The spatial and temporal structures of magnetic signal in the tokamak is analyzed using recently developed singular value decomposition (SVD) technique to determine the structure of current perturbation as the discharge progresses. In this work we use SVD technique for that purpose in IR-T1 tokamak.ootnotetextC. Nardonet, ``Multichannel Fluctuation Data Analysis By The Singular Value Decomposition Method Application To MHD Modes In Jet,'' Plasma Physics & Controlled Fusion, V. 34, No. 9, 1992, 1447-1465

  14. Theoretical reason for the lack of influence of 1H-14N cross-relaxation on the water proton T 1 NMRD profile in slow tumbling proteins

    NASA Astrophysics Data System (ADS)

    Westlund, P.-O.

    2012-09-01

    For immobilized protein the water proton T 1-NMRD profile displays three enhanced relaxation peaks (QP). For slow tumbling proteins these relaxation peaks are not experimentally observed. However, the theoretically determined QP effect on the amide proton T 1-NMRD profile displays a distorted Lorentzian dispersion profile. The question arises as to whether there is also a distortion of the water-proton T 1-NMRD profile due to QP. The model of Sunde and Halle [J. Magn. Reson. 203, 257 (2010)] predicts a decreasing QP relaxation contribution and, with the aid of a model for tumbling proteins [P.-O. Westlund, Phys. Chem. Chem. Phys, 12, 3136 (2010)], it is shown that the QP effect is absent in water-proton T 1-NMRD profiles for slow tumbling proteins with τR < 1 µs, τI.

  15. A Longitudinal (6-week) 3T (1)H-MRS Study on the Effects of Lithium Treatment on Anterior Cingulate Cortex Metabolites in Bipolar Depression.

    PubMed

    Machado-Vieira, Rodrigo; Gattaz, Wagner F; Zanetti, Marcus V; De Sousa, Rafael T; Carvalho, Andre F; Soeiro-de-Souza, Marcio G; Leite, Claudia C; Otaduy, Maria C

    2015-12-01

    The anterior cingulate cortex (ACC) is a key area in mood regulation. To date, no longitudinal study has specifically evaluated lithium׳s effects on ACC metabolites using (1)H-MRS, as well as its association with clinical improvement in bipolar depression. This (1)H-MRS (TE=35ms) study evaluated 24 drug-free BD patients during depressive episodes and after lithium treatment at therapeutic levels. Brain metabolite levels (N-acetyl aspartate (NAA), creatine (tCr), choline, myo-inositol, and glutamate levels) were measured in the ACC at baseline (week 0) and after lithium monotherapy (week 6). The present investigation showed that ACC glutamate (Glu/tCr) and glutamate+glutamine (Glx/tCr) significantly increased after six weeks of lithium therapy. Regarding the association with clinical improvement, remitters showed an increase in myoinositol levels (mI/tCr) after lithium treatment compared to non-remitters. The present findings reinforce a role for ACC glutamate-glutamine cycling and myoinositol pathway as key targets for lithium׳s therapeutic effects in BD. PMID:26428274

  16. Relationship between Knee Alignment and T1rho Values of Articular Cartilage and Menisci in Patients with Knee Osteoarthritis

    PubMed Central

    Wang, Ligong; Vieira, Renata La Rocca; Rybak, Leon D.; Babb, James S.; Chang, Gregory; Krasnokutsky, Svetlana; Abramson, Steven; Regatte, Ravinder

    2013-01-01

    Objective To assess the relationship between knee alignment and subregional T1rho values of the femorotibial cartilage and menisci in patients with mild (Kellgren-Lawrence grade 1) to moderate (KL3) osteoarthritis (OA) at 3T. Materials and methods 26 subjects with a clinical diagnosis of KL1-3 OA were included and subdivided into three subgroups: varus, valgus, and neutral. All subjects were evaluated on a 3T MR scanner. Mann-Whitney and Wilcoxon signed rank tests were performed to determine any statistically significant differences in subregional T1rho values of femorotibial cartilage and menisci among the three subgroups of KL1-3 OA patients. Results Medial femoral anterior cartilage subregion in varus group had significantly higher (p < 0.05) T1rho values than all cartilage subregions in valgus group. Medial tibial central cartilage subregion had significantly higher T1rho values (p < 0.05) than lateral tibial central cartilage subregion in varus group. The posterior horn of the medial meniscus in neutral group had significantly higher T1rho values (p < 0.0029) than all meniscus subregions in valgus group. Conclusion There exists some degree of association between knee alignment and subregional T1rho values of femorotibial cartilage and menisci in patients with clinical OA. PMID:23769189

  17. The Clinical Value of High-Intensity Signals on the Coronary Atherosclerotic Plaques: Noncontrast T1-Weighted Magnetic Resonance Imaging

    PubMed Central

    Ehara, Shoichi; Matsumoto, Kenji; Shimada, Kenei

    2016-01-01

    Over the past several decades, significant progress has been made in the pathohistological assessment of vulnerable plaques and in invasive intravascular imaging techniques. However, the assessment of plaque morphology by invasive modalities is of limited value for the detection of subclinical coronary atherosclerosis and the subsequent prediction or prevention of acute cardiovascular events. Recently, magnetic resonance (MR) imaging technology has reached a sufficient level of spatial resolution, which allowed the plaque visualization of large and static arteries such as the carotids and aorta. However, coronary wall imaging by MR is still challenging due to the small size of coronary arteries, cardiac and respiratory motion, and the low contrast-to-noise ratio between the coronary artery wall and the surrounding structures. Following the introduction of carotid plaque imaging with noncontrast T1-weighted imaging (T1WI), some investigators have reported that coronary artery high-intensity signals on T1WI are associated with vulnerable plaque morphology and an increased risk of future cardiac events. Although there are several limitations and issues that need to be resolved, this novel MR technique for coronary plaque imaging could influence treatment strategies for atherothrombotic disease and may be useful for understanding the pathophysiological mechanisms of atherothrombotic plaque formation. PMID:27455243

  18. Development of qualitative and quantitative analysis methods in pharmaceutical application with new selective signal excitation methods for 13 C solid-state nuclear magnetic resonance using 1 H T1rho relaxation time.

    PubMed

    Nasu, Mamiko; Nemoto, Takayuki; Mimura, Hisashi; Sako, Kazuhiro

    2013-01-01

    Most pharmaceutical drug substances and excipients in formulations exist in a crystalline or amorphous form, and an understanding of their state during manufacture and storage is critically important, particularly in formulated products. Carbon 13 solid-state nuclear magnetic resonance (NMR) spectroscopy is useful for studying the chemical and physical state of pharmaceutical solids in a formulated product. We developed two new selective signal excitation methods in (13) C solid-state NMR to extract the spectrum of a target component from such a mixture. These methods were based on equalization of the proton relaxation time in a single domain via rapid intraproton spin diffusion and the difference in proton spin-lattice relaxation time in the rotating frame ((1) H T1rho) of individual components in the mixture. Introduction of simple pulse sequences to one-dimensional experiments reduced data acquisition time and increased flexibility. We then demonstrated these methods in a commercially available drug and in a mixture of two saccharides, in which the (13) C signals of the target components were selectively excited, and showed them to be applicable to the quantitative analysis of individual components in solid mixtures, such as formulated products, polymorphic mixtures, or mixtures of crystalline and amorphous phases. PMID:23147444

  19. High resolution 1H solid state NMR studies of polyethyleneterephthalate

    NASA Astrophysics Data System (ADS)

    Cheung, T. T. P.; Gerstein, B. C.; Ryan, L. M.; Taylor, R. E.; Dybowski, D. R.

    1980-12-01

    Molecular motions and spatial properties of the solid polymer polyethyleneterephthalate have been investigated using high resolution 1H solid state NMR techniques. The longitudinal spin relaxation time T1ρ of protons (1H) in the rotating frame was measured for a spin locking field ranging from 5 to 20 G. The decay of the 1H magnetization indicated the existence of two distinct T1ρ's and their field dependence shows that they are associated with two mobile phases of the polymer. The 1H magnetization also relaxes under the dipolar narrowed Carr-Purcell (DNCP) multipulse sequence with two dintinct T1y relaxation times. The ratios T1y's and T1ρ's deviate significantly from the expected theoretical values. The combined experiment with magic angle spinning and the DNCP sequence followed by homonuclear dipolar decoupling reveals the individual T1y relaxation of the resolved methylene and aromatic protons. These two species of protons were found to relax with the same T1y's, thus implying that spin diffusion must have taken place under the homonuclear dipolar decoupling multipulse. The qualitative description of spin diffusion under homonuclear decoupling is given. The combined experiment with spin locking and the DNCP sequence yields the correspondence between the two T1ρ's and the two T1y's. The long T1ρ corresponds to the short T1y whereas the short T1ρ corresponds to the long T1y. Communication between the two spatial phases via spin diffusion was also observed in this experiment by monitoring the recovery of the 1H magnitization associated with the short T1ρ after it has been eliminated during the spin locking. The total 1H magnetization is allowed to equilibrate in the laboratory frame for a variable time much shorter than T1 after the spin locking field has been turned off. The spatial relationship between the two phases is discussed.

  20. Determination of the QEC values of the T =1 /2 mirror nuclei 21Na and 29P at LEBIT

    NASA Astrophysics Data System (ADS)

    Eibach, M.; Bollen, G.; Brodeur, M.; Cooper, K.; Gulyuz, K.; Izzo, C.; Morrissey, D. J.; Redshaw, M.; Ringle, R.; Sandler, R.; Schwarz, S.; Sumithrarachchi, C. S.; Valverde, A. A.; Villari, A. C. C.

    2015-10-01

    We report the first direct measurement of the transition energy QEC of the 21Na mixed Fermi-Gamow-Teller decay. This is the first of the T =1 /2 mirror nuclei decays used for the determination of Vud to be measured with Penning trap mass spectrometry. In addition, the 29P mass was measured directly for the first time and used along with the mass of its daughter, 29Si, for the independent QEC determination of this decay. The obtained QEC(21Na)=3547.11 (9 ) keV and ME (29P)=-169 53.15 (47 ) keV significantly improve the latest published values and reduce the contribution of the QEC uncertainty on F tmirror to the same order as the theoretical corrections.

  1. Rapid determination of γ-value and xanthate group distribution on viscose by liquid-state (1)H NMR spectroscopy.

    PubMed

    Wöss, Kateryna; Weber, Hansjörg; Grundnig, Peter; Röder, Thomas; Weber, Hedda K

    2016-05-01

    A method for the determination of the γ-value and more importantly the distribution of xanthate groups on cellulose xanthate produced during the viscose process is presented. The method is based upon stabilization of xanthate groups attached to the cellulose chain by reaction with 4-methylbenzyl bromide and analysis of the resulting product by liquid-state (1)H NMR. Careful analysis of the proton-spectrum using deconvolution gave a very fast method for the measurement of the γ-value which compared well with the data obtained by IR spectroscopy. In addition it could be shown that the distribution of the xanthate groups on the anhydroglucose monomeric unit (xanthation at position 2, 3 or 6) changes significantly during ripening. The method gave useful results even for viscose with low γ-values of about 25. PMID:26877011

  2. Poor prognostic value of lymphovascular invasion for pT1 urothelial carcinoma with squamous differentiation in bladder cancer

    PubMed Central

    Li, Gang; Song, Hualin; Wang, Jiaxin; Bao, Yali; Niu, Yuanjie

    2016-01-01

    Lymphovascular invasion (LVI) is the primary and essential step in the systemic dissemination of cancer cells. The aim of our study was to assess the independent prognostic role of LVI for pT1 urothelial carcinoma with squamous differentiation in bladder cancer. We retrospectively analyzed the clinical and pathological information of 206 patients diagnosed pT1 urothelial carcinoma with squamous differentiation. Of the 206 patients, LVI was detected in 57 (27.6%) patients. The 5 year cancer specific survival (CSS) rates were 87.2% in LVI (−) and 52.4% in LVI (+) (p < 0.001). According to univariate analysis, tumor multiplicity, tumor size, recurrence and LVI were the prognostic factors associated with CSS. Additionally, tumor size and LVI significantly influenced the CSS in multivariate analysis. TURBT had shorter median CSS than RC in recurred patients with LVI (+). Our study suggested that LVI is an important predictor for survival of pT1 urothelial carcinoma with squamous differentiation. LVI positive status and tumor size ≥3 cm led to a higher risk of death. RC should be routinely performed in recurred LVI (+) bladder cancer patients of pT1 urothelial carcinoma with squamous differentiation. PMID:27279531

  3. Poor prognostic value of lymphovascular invasion for pT1 urothelial carcinoma with squamous differentiation in bladder cancer.

    PubMed

    Li, Gang; Song, Hualin; Wang, Jiaxin; Bao, Yali; Niu, Yuanjie

    2016-01-01

    Lymphovascular invasion (LVI) is the primary and essential step in the systemic dissemination of cancer cells. The aim of our study was to assess the independent prognostic role of LVI for pT1 urothelial carcinoma with squamous differentiation in bladder cancer. We retrospectively analyzed the clinical and pathological information of 206 patients diagnosed pT1 urothelial carcinoma with squamous differentiation. Of the 206 patients, LVI was detected in 57 (27.6%) patients. The 5 year cancer specific survival (CSS) rates were 87.2% in LVI (-) and 52.4% in LVI (+) (p < 0.001). According to univariate analysis, tumor multiplicity, tumor size, recurrence and LVI were the prognostic factors associated with CSS. Additionally, tumor size and LVI significantly influenced the CSS in multivariate analysis. TURBT had shorter median CSS than RC in recurred patients with LVI (+). Our study suggested that LVI is an important predictor for survival of pT1 urothelial carcinoma with squamous differentiation. LVI positive status and tumor size ≥3 cm led to a higher risk of death. RC should be routinely performed in recurred LVI (+) bladder cancer patients of pT1 urothelial carcinoma with squamous differentiation. PMID:27279531

  4. Comparison of myocardial T1 and T2 values in 3 T with T2* in 1.5 T in patients with iron overload and controls.

    PubMed

    Camargo, Gabriel C; Rothstein, Tamara; Junqueira, Flavia P; Fernandes, Elsa; Greiser, Andreas; Strecker, Ralph; Pessoa, Viviani; Lima, Ronaldo S L; Gottlieb, Ilan

    2016-05-01

    Myocardial iron quantification remains limited to 1.5 T systems with T2* measurement. The present study aimed at comparing myocardial T2* values at 1.5 T to T1 and T2 mapping at 3.0 T in patients with iron overload and healthy controls. A total of 17 normal volunteers and seven patients with a history of myocardial iron overload were prospectively enrolled. Mid-interventricular septum T2*, native T1 and T2 times were quantified on the same day, using a multi-echo gradient-echo sequence at 1.5 T and T1 and T2 mapping sequences at 3.0 T, respectively. Subjects with myocardial iron overload (T2* < 20 ms) in comparison with those without had significantly lower mean myocardial T1 times (868.9 ± 120.2 vs. 1170.3 ± 25.0 ms P = 0.005 respectively) and T2 times (34.9 ± 4.7 vs. 45.1 ± 2.0 ms P = 0.007 respectively). 3 T T1 and T2 times strongly correlated with 1.5 T, T2* times (Pearson's r = 0.95 and 0.91 respectively). T1 and T2 measures presented less variability than T2* in inter- and intra-observer analysis. Native myocardial T1 and T2 times at 3 T correlate closely with T2* times at 1.5 T and may be useful for myocardial iron overload quantification. PMID:26872908

  5. Joint inversion of T1-T2 spectrum combining the iterative truncated singular value decomposition and the parallel particle swarm optimization algorithms

    NASA Astrophysics Data System (ADS)

    Ge, Xinmin; Wang, Hua; Fan, Yiren; Cao, Yingchang; Chen, Hua; Huang, Rui

    2016-01-01

    With more information than the conventional one dimensional (1D) longitudinal relaxation time (T1) and transversal relaxation time (T2) spectrums, a two dimensional (2D) T1-T2 spectrum in a low field nuclear magnetic resonance (NMR) is developed to discriminate the relaxation components of fluids such as water, oil and gas in porous rock. However, the accuracy and efficiency of the T1-T2 spectrum are limited by the existing inversion algorithms and data acquisition schemes. We introduce a joint method to inverse the T1-T2 spectrum, which combines iterative truncated singular value decomposition (TSVD) and a parallel particle swarm optimization (PSO) algorithm to get fast computational speed and stable solutions. We reorganize the first kind Fredholm integral equation of two kernels to a nonlinear optimization problem with non-negative constraints, and then solve the ill-conditioned problem by the iterative TSVD. Truncating positions of the two diagonal matrices are obtained by the Akaike information criterion (AIC). With the initial values obtained by TSVD, we use a PSO with parallel structure to get the global optimal solutions with a high computational speed. We use the synthetic data with different signal to noise ratio (SNR) to test the performance of the proposed method. The result shows that the new inversion algorithm can achieve favorable solutions for signals with SNR larger than 10, and the inversion precision increases with the decrease of the components of the porous rock.

  6. T1, T2, and relative proton density at 0. 35 T for spleen, liver, adipose tissue, and vertebral body: normal values

    SciTech Connect

    Nyman, R.; Ericsson, A.; Hemmingsson, A.; Jung, B.; Sperber, G.; Thuomas, K.A.

    1986-12-01

    An MRI installation (Magnetom, Siemens, software version B1 of NUMARIS) working at 0.35 T was used to estimate T1, T2, and relative proton density in the spleen, liver, adipose tissue, and vertebral body in 14 healthy volunteers. Two double-echo sequences were applied for all subjects: TR = 500 ms, TE1 = 35 and TE2 = 70 ms; and TR = 1600 ms, TE1 = 35 and TE2 = 70 ms. The images were sampled in regions of interest and appropriate relaxation expressions fitted to the ROI data yielding relaxation parameters and relative proton densities. Relaxation expressions, included in standard software (Siemens), were compared to more elaborate functions, developed in parallel to this study. The latter were found more appropriate, especially for high T1 values, and gave the following mean values for the four tissues (estimated uncertainty of mean in parentheses) T1 (ms) 915(36), 428(5), 261(7), and 501(11); T2 (ms) 79.7(8.8), 51.0(0.2), 59.8(1.0), and 64.7(0.8); and corresponding relative proton density (rho, arbitrary units) 2088(136), 2182(10), 2915(49), and 2136(21). The uncertainty in the values was estimated in the fitting procedure and does not include systematic errors. The relative noise in the ROIs was about 9% and the reproducibility of the ROI mean values about 8%.

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

  8. Properties of sesame oil by detailed 1H and 13C NMR assignments before and after ozonation and their correlation with iodine value, peroxide value, and viscosity measurements.

    PubMed

    Sega, Alessandro; Zanardi, Iacopo; Chiasserini, Luisa; Gabbrielli, Alessandro; Bocci, Velio; Travagli, Valter

    2010-02-01

    Gaseous ozone chemically reacts with unsaturated triglyceride substrates leading to ozonated derivatives with a wide potential applications, ranging from the petrochemical to the pharmaceutical industry. To date, an ultimate understanding of the ozone reactivity during sesame oil ozonation process as well as detailed (1)H and (13)C NMR assignments are lacking. A practical advantage of NMR is that a single NMR sample measurement can explain many issues, while similar analysis by traditional methods may require several independent and time-consuming measurements. Moreover, significant relationships among NMR spectra and both conventional chemical analysis and viscosity measurements have been found. Eventually, NMR could play an important role for quality attributes of ozonated oil derivatives. PMID:19900426

  9. Determination of pKa values of some novel benzimidazole salts by using a new approach with (1)H NMR spectroscopy.

    PubMed

    Mumcu, Akın; Küçükbay, Hasan

    2015-12-01

    Benzimidazoles and their derivatives including imidazole are studied widely because they exist in the structure of natural products and different drugs. pKa values are extremely important for drug discovery and improvement in order to determine pharmacokinetic and pharmacodynamic features such as permeation through biological barriers, interactions with the target area or side effects. Acid-base features (pKa ) have great importance not only for physiological characteristics but also for being used as a ligand or changing physico-chemical features by turning benzimidazoles into salts. Within the scope of this study, a variety of new benzimidazole salts were synthesized, and their characterizations were made by NMR spectroscopy, FTIR spectroscopy and element analysis techniques. The pKa values of synthesized benzimidazole salts were determined by inflection point approach using integration values obtained with (1) H NMR spectroscopy and Henderson-Hasselbalch analysis. pKa values of some benzimidazole salts were also determined by potentiometric methods in order to compare those of NMR spectroscopy results. PMID:26256272

  10. Synthesis, determination of p Ka values and GIAO NMR calculations of some new 3-alkyl-4-( p-methoxybenzoylamino)-4,5-dihydro-1 H-1,2,4-triazol-5-ones

    NASA Astrophysics Data System (ADS)

    Yüksek, Haydar; Alkan, Muzaffer; Bahçeci, Şule; Cakmak, Ismail; Ocak, Zafer; Baykara, Haci; Aktaş, Ozlem; Ağyel, Elif

    2008-02-01

    3-Alkyl-4-amino-4,5-dihydro-1 H-1,2,4-triazol-5-ones ( 2) reacted with p-methoxybenzoyl chloride to afford the corresponding 3-alkyl-4-( p-methoxybenzoylamino)-4,5-dihydro-1 H-1,2,4-triazol-5-ones ( 3). Five newly synthesized compounds have been characterized by elemental analyses, IR, 1H NMR, 13C NMR and UV spectral data. The newly synthesized compounds 3 were titrated potentiometrically with tetrabutylammonium hydroxide in four non-aqueous solvents such as acetonitrile, isopropyl alcohol, tert-butyl alcohol and N, N-dimethylformamide, and the half-neutralization potential values and the corresponding p Ka values were determined for all cases. Thus, the effects of solvents and molecular structure upon acidity were investigated. In addition, isotropic 1H and 13C nuclear magnetic shielding constants of compounds 3 were obtained by the gauge-including-atomic-orbital (GIAO) method at the B3LYP density functional level. The geometry of each compound has been optimized using the 6-311G basis set. Theoretical values were compared to the experimental data.

  11. Both water source and atmospheric water impact leaf wax n-alkane 2H/1H values of hydroponically grown angiosperm trees

    NASA Astrophysics Data System (ADS)

    Tipple, B. J.; Berke, M. A.; Hambach, B.; Roden, J. S.; Ehleringer, J. R.

    2013-12-01

    The extent to which both water source and leaf water 2H-enrichment affect the δ2H values of terrestrial plant leaf waxes is an area of active research as ecologists seek a mechanistic understanding of the environmental determinants of leaf wax isotope values before applying δ2H values of leaf waxes to reconstruct past hydrologic conditions. To elucidate the effects of both water source and atmospheric water vapor on δ2H values of leaf waxes for broad-leaved angiosperms, we analyzed hydrogen isotope ratios of high-molecular weight n-alkanes from two tree species that were grown throughout the spring and summer (five months) in a hydroponic system under controlled atmospheric conditions. Here, 12 subpopulations each of Populus fremontii and Betula occidentalis saplings were grown under one of six source different waters ranging in hydrogen isotope ratio values from -120 to +180 ‰ and under either 40 % or 75 % relative humidity conditions. We found n-alkane δ2H values of both species were linearly related to source water δ2H values with differences in slope associated with differing atmospheric humidity. A Craig-Gordon model was used to predict the δ2H values of leaf water and, by extension, n-alkane δ2H values under the range of growth conditions. The modeled leaf water values were found to be linearly related to observed n-alkane δ2H values with a statistically indistinguishable slope between the high and low humidity treatments. These leaf wax observations support a constant biosynthetic fractionation factor between evaporatively-enriched leaf water and n-alkanes for each species. However, we found the calculated biosynthetic fractionation between modeled leaf-water and n-alkane to be different between the two species. We submit that these dissimilarities were due to model inputs and not differences in the specific-species biochemistry. Nonetheless, these results are significant as they indicated that the δ2H value of atmospheric water vapor and

  12. T-1 Training Area

    SciTech Connect

    2014-11-07

    Another valuable homeland security asset at the NNSS is the T-1 training area, which covers more than 10 acres and includes more than 20 separate training venues. Local, County, and State first responders who train here encounter a variety of realistic disaster scenarios. A crashed 737 airliner lying in pieces across the desert, a helicopter and other small aircraft, trucks, buses, and derailed train cars are all part of the mock incident scene. After formal classroom education, first responders are trained to take immediate decisive action to prevent or mitigate the use of radiological or nuclear devices by terrorists. The Counterterrorism Operations Support Center for Radiological Nuclear Training conducts the courses and exercises providing first responders from across the nation with the tools they need to protect their communities. All of these elements provide a training experience that cannot be duplicated anywhere else in the country.

  13. T-1 Training Area

    ScienceCinema

    None

    2015-01-09

    Another valuable homeland security asset at the NNSS is the T-1 training area, which covers more than 10 acres and includes more than 20 separate training venues. Local, County, and State first responders who train here encounter a variety of realistic disaster scenarios. A crashed 737 airliner lying in pieces across the desert, a helicopter and other small aircraft, trucks, buses, and derailed train cars are all part of the mock incident scene. After formal classroom education, first responders are trained to take immediate decisive action to prevent or mitigate the use of radiological or nuclear devices by terrorists. The Counterterrorism Operations Support Center for Radiological Nuclear Training conducts the courses and exercises providing first responders from across the nation with the tools they need to protect their communities. All of these elements provide a training experience that cannot be duplicated anywhere else in the country.

  14. U1h Superstructure

    SciTech Connect

    Glen Sykes

    2000-11-01

    The U1H Shaft Project is a design build subcontract to supply the U. S. Department of Energy (DOE) a 1,045 ft. deep, 20 ft. diameter, concrete lined shaft for unspecified purposes. The subcontract awarded to Atkinson Construction by Bechtel Nevada to design and construct the shaft for the DOE has been split into phases with portions of the work being released as dictated by available funding. The first portion released included the design for the shaft, permanent hoist, headframe, and collar arrangement. The second release consisted of constructing the shaft collar to a depth of 110 ft., the service entry, utility trenches, and installation of the temporary sinking plant. The temporary sinking plant included the installation of the sinking headframe, the sinking hoist, two deck winches, the shaft form, the sinking work deck, and temporary utilities required to sink the shaft. Both the design and collar construction were completed on schedule. The third release consisted of excavating and lining the shaft to the station depth of approximately 950 feet. Work is currently proceeding on this production sinking phase. At a depth of approximately 600 feet, Atkinson has surpassed production expectation and is more than 3 months ahead of schedule. Atkinson has employed the use of a Bobcat 331 excavator as the primary means of excavation. the shaft is being excavated entirely in an alluvial deposit with varying degrees of calcium carbonate cementation. Several more work packages are expected to be released in the near future. The remaining work packages include, construction of the shaft station a depth of 975 ft. and construction of the shaft sump to a depth of 1,045 ft., installation of the loading pocket and station steel and equipment, installation of the shaft steel and guides, installation of the shaft utilities, and installation of the permanent headframe, hoist, collar utilities, and facilities.

  15. The Dual-Angle Method for Fast, Sensitive T1 Measurement in Vivo with Low-Angle Adiabatic Pulses

    NASA Astrophysics Data System (ADS)

    Bottomley, P. A.; Ouwerkerk, R.

    A new method for measuring T1 based on a measurement of the ratio, R, of the steady-state partially saturated NMR signals acquired at two fixed low flip angles (<90°) and a single sequence-repetition period, TR, is presented, The flip angles are chosen to optimize both the signal-to-noise ratio per unit time relative to the best possible Ernst-angle performance and the sensitivity with which a measurement of R can resolve differences in T1. A flip-angle pair at of around (60°, 15°) yields 70-79% of the maximum achievable Ernst-angle signal-to-noise ratio and a near-linear dependence of R on TR/ T1 with gradient of about 2:1 over the range 0.1 ≤ TR/ T1 ≤ 1. Errors in hip-angle and excitation-field ( B1) inhomogeneity result in roughly proportionate errors in the apparent T1. The method is best implemented with adiabatic low-angle pulses such as B1-independent rotation (BIR-4) or BIR-4 phase-cycled (BIRP) pulses, which permit measurements with surface coils. Experimental validation was obtained at 2 T by comparison of unlocalized inversion-recovery and dual-angle proton ( 1H) and phosphorus ( 31P) measurements from vials containing doped water with 0.04 ≤ T1 ≤ 2.8 s and from the metabolites in the calf muscles of eight human volunteers. Calf muscle values of 6 ± 0.5 s for phosphocreatine and around 3.7 ± 0.8 s for the adenosine triphosphates (ATP) were in good agreement with inversion-recovery T1 values and values from the literature. Use of the dual-angle method accelerated T1 measurement time by about fivefold over inversion recovery. The dual-angle method was implemented in a one-dimensional localized surface-coil 31P spectroscopy sequence, producing consistent T1 measurements from phantoms, the calf muscle, and the human liver. 31P T1 values of ATP in the livers of six volunteers were about 0.5 ± 0.1 to 0.6 ± 0.2 s: the total exam times were about 35 minutes per subject. The method is ideally suited to low-sensitivity and/or low

  16. GABA and glutamate in schizophrenia: A 7 T 1H-MRS study

    PubMed Central

    Marsman, Anouk; Mandl, René C.W.; Klomp, Dennis W.J.; Bohlken, Marc M.; Boer, Vincent O.; Andreychenko, Anna; Cahn, Wiepke; Kahn, René S.; Luijten, Peter R.; Hulshoff Pol, Hilleke E.

    2014-01-01

    Schizophrenia is characterized by loss of brain volume, which may represent an ongoing pathophysiological process. This loss of brain volume may be explained by reduced neuropil rather than neuronal loss, suggesting abnormal synaptic plasticity and cortical microcircuitry. A possible mechanism is hypofunction of the NMDA-type of glutamate receptor, which reduces the excitation of inhibitory GABAergic interneurons, resulting in a disinhibition of glutamatergic pyramidal neurons. Disinhibition of pyramidal cells may result in excessive stimulation by glutamate, which in turn could cause neuronal damage or death through excitotoxicity. In this study, GABA/creatine ratios, and glutamate, NAA, creatine and choline concentrations in the prefrontal and parieto-occipital cortices were measured in 17 patients with schizophrenia and 23 healthy controls using proton magnetic resonance spectroscopy at an ultra-high magnetic field strength of 7 T. Significantly lower GABA/Cr ratios were found in patients with schizophrenia in the prefrontal cortex as compared to healthy controls, with GABA/Cr ratios inversely correlated with cognitive functioning in the patients. No significant change in the GABA/Cr ratio was found between patients and controls in the parieto-occipital cortex, nor were levels of glutamate, NAA, creatine, and choline differed in patients and controls in the prefrontal and parieto-occipital cortices. Our findings support a mechanism involving altered GABA levels distinguished from glutamate levels in the medial prefrontal cortex in schizophrenia, particularly in high functioning patients. A (compensatory) role for GABA through altered inhibitory neurotransmission in the prefrontal cortex may be ongoing in (higher functioning) patients with schizophrenia. PMID:25379453

  17. Dynamic stereochemistry of erigeroside by measurement of 1H- 1H and 13C- 1H coupling constants

    NASA Astrophysics Data System (ADS)

    Tafazzoli, Mohsen; Ghiasi, Mina; Moridi, Mahdi

    2008-07-01

    Erigeroside was extracted from Satureja khuzistanica Jamzad (Marzeh Khuzistani in Persian, family of lamiaceae), and 1H, 13C, 13C{ 1H}, 1H- 1H COSY, HMQC and J-HMBC were obtained to identify this compound and determine a complete set of J-coupling constants ( 1JC-H, 2JC-H, 3JC-H and 3JH-H) values within the exocyclic hydroxymethyl group (CH 2OH) and anomeric center. In parallel, density functional theory (DFT) using B3LYP functional and split-valance 6-311++G** basis set has been used to optimized the structures and conformers of erigeroside. In all calculations solvent effects were considered using a polarized continuum (overlapping spheres) model (PCM). The dependencies of 1J, 2J and 3J involving 1H and 13C on the C 5'-C 6' ( ω), C 6'-O 6' ( θ) and C 1'-O 1' ( φ) torsion angles in erigeroside were computed using DFT method. Complete hyper surfaces for 1JC1',H1', 2JC5',H6'R, 2JC5',H6'S, 2JC6',H5', 3JC4',H6'R, 3JC4',H6'S and 2JH6'R-H5'S as well as 3JH5',H6'R were obtained and used to derive Karplus equations to correlate these couplings to ω, θ and φ. These calculated J-couplings are in agreement with experimental values. These results confirm the reliability of DFT calculated coupling constants in aqueous solution.

  18. Experimental Study of Calculated t1 Images Under Flow Conditions Using Protons and FLUORINE-19 in Magnetic Resonance Imaging

    NASA Astrophysics Data System (ADS)

    Zheng, Jie

    A gradient refocused echo (GRE) pulse protocol has been developed and implemented to obtain calculated T1 images under flow conditions. This sequence acquires multiple images with different flip angles and uses a least -square fit to obtain calculated T1 images. A theoretical analysis of imprecision in the calculated T1 images is discussed. In accordance with Wang (49), the optimal parameters as determined by computer simulation were found to be 20 ^circ and 100^ circ for the flip angles in a two point fit for TR falling in the range 0.3 to 1.0 T1. Flow compensation was added to the pulse sequence for imaging flow phantoms containing GD-DTPA doped water and perfluorocarbon (PFC) compounds for a range of flow rates (0-55 cm/s). Flow compensation was found to effectively recover signal loss due to flow related dephasing. Experimental testing of this protocol has been performed on stationary proton and PFC compound phantoms utilizing ^1H and ^{19}F magnetic resonance imaging respectively. There is good agreement between the experimental results and the theoretical predictions about imprecision in the calculated T1 images. Analysis of variance of the mean T1 values of the calculated T1 images of the proton and PFC flow phantoms indicated that for the flow phantom geometry used in this study, there was no statistical difference among these mean T1 values from flow phantoms with different flow rates (including stationary status). It is believed that this protocol may provide an imaging method for mapping the pO _2 distribution in the vascular space in vivo utilizing perfluorocarbon compounds and ^ {19}F magnetic resonance imaging.

  19. Uncertainty estimations for quantitative in vivo MRI T1 mapping

    NASA Astrophysics Data System (ADS)

    Polders, Daniel L.; Leemans, Alexander; Luijten, Peter R.; Hoogduin, Hans

    2012-11-01

    Mapping the longitudinal relaxation time (T1) of brain tissue is of great interest for both clinical research and MRI sequence development. For an unambiguous interpretation of in vivo variations in T1 images, it is important to understand the degree of variability that is associated with the quantitative T1 parameter. This paper presents a general framework for estimating the uncertainty in quantitative T1 mapping by combining a slice-shifted multi-slice inversion recovery EPI technique with the statistical wild-bootstrap approach. Both simulations and experimental analyses were performed to validate this novel approach and to evaluate the estimated T1 uncertainty in several brain regions across four healthy volunteers. By estimating the T1 uncertainty, it is shown that the variation in T1 within anatomic regions for similar tissue types is larger than the uncertainty in the measurement. This indicates that heterogeneity of the inspected tissue and/or partial volume effects can be the main determinants for the observed variability in the estimated T1 values. The proposed approach to estimate T1 and its uncertainty without the need for repeated measurements may also prove to be useful for calculating effect sizes that are deemed significant when comparing group differences.

  20. Uncertainty estimations for quantitative in vivo MRI T1 mapping.

    PubMed

    Polders, Daniel L; Leemans, Alexander; Luijten, Peter R; Hoogduin, Hans

    2012-11-01

    Mapping the longitudinal relaxation time (T(1)) of brain tissue is of great interest for both clinical research and MRI sequence development. For an unambiguous interpretation of in vivo variations in T(1) images, it is important to understand the degree of variability that is associated with the quantitative T(1) parameter. This paper presents a general framework for estimating the uncertainty in quantitative T(1) mapping by combining a slice-shifted multi-slice inversion recovery EPI technique with the statistical wild-bootstrap approach. Both simulations and experimental analyses were performed to validate this novel approach and to evaluate the estimated T(1) uncertainty in several brain regions across four healthy volunteers. By estimating the T(1) uncertainty, it is shown that the variation in T(1) within anatomic regions for similar tissue types is larger than the uncertainty in the measurement. This indicates that heterogeneity of the inspected tissue and/or partial volume effects can be the main determinants for the observed variability in the estimated T(1) values. The proposed approach to estimate T(1) and its uncertainty without the need for repeated measurements may also prove to be useful for calculating effect sizes that are deemed significant when comparing group differences. PMID:23041796

  1. U1h shaft project

    SciTech Connect

    Brian Briggs; R. G. Musick

    2000-06-30

    The U1h shaft project is a design/build subcontract to construct one 20 foot (ft) finished diameter shaft to a depth of 1,045 ft at the Nevada Test Site. Atkinson Construction was subcontracted by Bechtel Nevada to construct the U1h Shaft for the Department of Energy. The project consists of furnishing and installing the sinking plant, construction of the 1,045 ft of concrete lined shaft, development of a shaft station at a depth of 976 ft, and construction of a loading pocket at the station. The outfitting of the shaft and installation of a new hoist may be incorporated into the project at a later date. This paper should be of interest to those involved with the construction of relatively deep shafts and underground excavations.

  2. Binding of thiocyanate to lactoperoxidase: 1H and 15N nuclear magnetic resonance studies

    SciTech Connect

    Modi, S.; Behere, D.V.; Mitra, S. )

    1989-05-30

    The binding of thiocyanate to lactoperoxidase (LPO) has been investigated by 1H and 15N NMR spectroscopy. 1H NMR of LPO shows that the major broad heme methyl proton resonance at about 61 ppm is shifted upfield by addition of the thiocyanate, indicating binding of the thiocyanate to the enzyme. The pH dependence of line width of 15N resonance of SC15N- in the presence of the enzyme has revealed that the binding of the thiocyanate to the enzyme is facilitated by protonation of an ionizable group (with pKa of 6.4), which is presumably distal histidine. Dissociation constants (KD) of SC15N-/LPO, SC15N-/LPO/I-, and SC15N-/LPO/CN- equilibria have been determined by 15N T1 measurements and found to be 90 +/- 5, 173 +/- 20, and 83 +/- 6 mM, respectively. On the basis of these values of KD, it is suggested that the iodide ion inhibits the binding of the thiocyanate but cyanide ion does not. The thiocyanate is shown to bind at the same site of LPO as iodide does, but the binding is considerably weaker and is away from the ferric ion. The distance of 15N of the bound thiocyanate ion from the iron is determined to be 7.2 +/- 0.2 A from the 15N T1 measurements.

  3. [Treatment options of T1 glottic carcinoma].

    PubMed

    Wang, Qi; Fan, Guokang

    2016-01-01

    T1 glottic carcinoma is part of early laryngeal carcinoma which involves the vocal cords, including anterior commissure or posterior commissure. We analyzed the treatment options of T1 glottic carcinoma by reviewing the related literatures about T1 glottic carcinoma treated by conservative surgery (open surgery and laser microsurgery), radiotherapy, robot surgery, photodynamic treatment. PMID:27192922

  4. Assessing Myocardial Disease Using T1ρ MRI.

    PubMed

    Han, Yuchi; Liimatainen, Timo; Gorman, Robert C; Witschey, Walter R T

    2014-02-01

    There is great interest to use magnetic resonance imaging (MRI) for non-invasive assessment of myocardial disease in ischemic and non-ischemic cardiomyopathies. Recently, there has been a renewed interest to use a magnetic resonance imaging (MRI) technique utilizing spin locking radiofrequency (RF) pulses, called T1ρ MRI. The spin locking RF pulse creates sensitivity to some mechanisms of nuclear relaxation such as (1)H exchange between water and amide, amine and hydroxyl functional groups in molecules; consequently, there is the potential to non-invasively, and without exogenous contrast agents, obtain important molecular information from diseased myocardial tissue. The purpose of this article is to review and critically examine the recent published literature in the field related to T1ρ MRI of myocardial disease. PMID:24688628

  5. Assessing Myocardial Disease Using T1ρ MRI

    PubMed Central

    Han, Yuchi; Liimatainen, Timo; Gorman, Robert C.

    2014-01-01

    There is great interest to use magnetic resonance imaging (MRI) for non-invasive assessment of myocardial disease in ischemic and non-ischemic cardiomyopathies. Recently, there has been a renewed interest to use a magnetic resonance imaging (MRI) technique utilizing spin locking radiofrequency (RF) pulses, called T1ρ MRI. The spin locking RF pulse creates sensitivity to some mechanisms of nuclear relaxation such as 1H exchange between water and amide, amine and hydroxyl functional groups in molecules; consequently, there is the potential to non-invasively, and without exogenous contrast agents, obtain important molecular information from diseased myocardial tissue. The purpose of this article is to review and critically examine the recent published literature in the field related to T1ρ MRI of myocardial disease. PMID:24688628

  6. Cardiac magnetic resonance T1 mapping of left atrial myocardium

    PubMed Central

    Beinart, Roy; Khurram, Irfan M.; Liu, Songtao; Yarmohammadi, Hirad; Halperin, Henry R.; Bluemke, David A.; Gai, Neville; van der Geest, Rob J.; Lima, Joao A.C.; Calkins, Hugh; Zimmerman, Stefan L.; Nazarian, Saman

    2013-01-01

    BACKGROUND Cardiac magnetic resonance (CMR) T1 mapping is an emerging tool for objective quantification of myocardial fibrosis. OBJECTIVES To (a) establish the feasibility of left atrial (LA) T1 measurements, (b) determine the range of LA T1 values in patients with atrial fibrillation (AF) vs healthy volunteers, and (c) validate T1 mapping vs LA intracardiac electrogram voltage amplitude measures. METHODS CMR imaging at 1.5 T was performed in 51 consecutive patients before AF ablation and in 16 healthy volunteers. T1 measurements were obtained from the posterior LA myocardium by using the modified Look-Locker inversion-recovery sequence. Given the established association of reduced electrogram amplitude with fibrosis, intracardiac point-by-point bipolar LA voltage measures were recorded for the validation of T1 measurements. RESULTS The median LA T1 relaxation time was shorter in patients with AF (387 [interquartile range 364–428] ms) compared to healthy volunteers (459 [interquartile range 418–532] ms; P < .001) and was shorter in patients with AF with prior ablation compared to patients without prior ablation (P = .035). In a generalized estimating equations model, adjusting for data clusters per participant, age, rhythm during CMR, prior ablation, AF type, hypertension, and diabetes, each 100-ms increase in T1 relaxation time was associated with 0.1 mV increase in intracardiac bipolar LA voltage (P = .025). CONCLUSIONS Measurement of the LA myocardium T1 relaxation time is feasible and strongly associated with invasive voltage measures. This methodology may improve the quantification of fibrotic changes in thin-walled myocardial tissues. PMID:23643513

  7. Hydrogen motion and local structure of metals in β-Ti1-yVyHx as studied by 1H NMR

    NASA Astrophysics Data System (ADS)

    Ueda, Takahiro; Hayashi, Shigenobu; Hayamizu, Kikuko

    1993-09-01

    Hydrogen motion in β-Ti1-yVyHx (y=0.2, 0.4, 0.6, and 0.8; x~1) alloys was studied by 1H NMR, with which the temperature and frequency dependences of proton spin-lattice relaxation times (T1) were measured over the temperature range 105-400 K and at frequencies 9, 22.5, 52, and 90 MHz. The temperature dependences of T1 change systematically with the metal composition; with a decrease in the concentration of V, the minimum value of T1 increases and the temperature at which T1 is minimized shifts to the higher-temperature side. These results are analyzed with two-site jumps of a proton between unequal potential wells, in which Brouwer's model is assumed to describe local structure of the alloys. Good agreement between the experimental and calculated T1 values is given by this treatment, unlike the isotropic diffusion model. The following three parameters are used for the calculation: activation energies for Ti and V are ETi=16 and EV=9.5 kJ/mol, respectively, and the frequency prefactor is τ0=1.5×10-11 s for 0.4<=y<=0.8. The obtained ETi and EV values agree with those of pure metal hydrides such as TiHx and VHx, respectively.

  8. Formation of a dinuclear copper(II) complex through the cleavage of Cvalue='Single-Bond'/>N bond of 1-benzoyl-3-(pyridin-2-yl)-1H-pyrazole

    SciTech Connect

    Shardin, Rosidah; Pui, Law Kung; Yamin, Bohari M.; Kassim, Mohammad B.

    2014-09-03

    A simple mononuclear octahedral copper(II) complex was attempted from the reaction of three moles of 1-benzoyl-3-(pyridin-2-yl)-1H-pyrazole and one mole of copper(II) perchlorate hexahydrate in methanol. However, the product of the reaction was confirmed to be a dinuclear copper(II) complex with μ-(3-(pyridin-2-yl)-pyrazolato) and 3-(pyridin-2-yl)-1H-pyrazole ligands attached to each of the Cu(II) centre atom. The copper(II) ion assisted the cleavage of the C{sub benzoyl}value='Single-Bond'/>N bond afforded a 3-(pyridin-2-yl)-1H-pyrazole molecule. Deprotonation of the 3-(pyridin-2-yl)-1H-pyrazole gave a 3-(pyridin-2-yl)-pyrazolato, which subsequently reacted with the Cu(II) ion to give the (3-(pyridin-2-yl)-pyrazolato)(3-(pyridin-2-yl)-1H-pyrazole)Cu(II) product moiety. The structure of the dinuclear complex was confirmed by x-ray crystallography. The complex crystallized in a monoclinic crystal system with P2(1)/n space group and cell dimensions of a = 12.2029(8) Å, b = 11.4010(7) Å, c = 14.4052(9) Å and β = 102.414(2)°. The compound was further characterized by mass spectrometry, CHN elemental analysis, infrared and UV-visible spectroscopy and the results concurred with the x-ray structure. The presence of d-d transition at 671 nm (ε = 116 dm{sup 3} mol{sup −1} cm{sup −1}) supports the presence of Cu(II) centres.

  9. Assessment of myocardial fibrosis with T1 mapping MRI.

    PubMed

    Everett, R J; Stirrat, C G; Semple, S I R; Newby, D E; Dweck, M R; Mirsadraee, S

    2016-08-01

    Myocardial fibrosis can arise from a range of pathological processes and its presence correlates with adverse clinical outcomes. Cardiac magnetic resonance (CMR) can provide a non-invasive assessment of cardiac structure, function, and tissue characteristics, which includes late gadolinium enhancement (LGE) techniques to identify focal irreversible replacement fibrosis with a high degree of accuracy and reproducibility. Importantly the presence of LGE is consistently associated with adverse outcomes in a range of common cardiac conditions; however, LGE techniques are qualitative and unable to detect diffuse myocardial fibrosis, which is an earlier form of fibrosis preceding replacement fibrosis that may be reversible. Novel T1 mapping techniques allow quantitative CMR assessment of diffuse myocardial fibrosis with the two most common measures being native T1 and extracellular volume (ECV) fraction. Native T1 differentiates normal from infarcted myocardium, is abnormal in hypertrophic cardiomyopathy, and may be particularly useful in the diagnosis of Anderson-Fabry disease and amyloidosis. ECV is a surrogate measure of the extracellular space and is equivalent to the myocardial volume of distribution of the gadolinium-based contrast medium. It is reproducible and correlates well with fibrosis on histology. ECV is abnormal in patients with cardiac failure and aortic stenosis, and is associated with functional impairment in these groups. T1 mapping techniques promise to allow earlier detection of disease, monitor disease progression, and inform prognosis; however, limitations remain. In particular, reference ranges are lacking for T1 mapping values as these are influenced by specific CMR techniques and magnetic field strength. In addition, there is significant overlap between T1 mapping values in healthy controls and most disease states, particularly using native T1, limiting the clinical application of these techniques at present. PMID:27005015

  10. In vivo quantification of hyperoxic arterial blood water T1.

    PubMed

    Siero, Jeroen C W; Strother, Megan K; Faraco, Carlos C; Hoogduin, Hans; Hendrikse, Jeroen; Donahue, Manus J

    2015-11-01

    Normocapnic hyperoxic and hypercapnic hyperoxic gas challenges are increasingly being used in cerebrovascular reactivity (CVR) and calibrated functional MRI experiments. The longitudinal arterial blood water relaxation time (T1a) change with hyperoxia will influence signal quantification through mechanisms relating to elevated partial pressure of plasma-dissolved O2 (pO2) and increased oxygen bound to hemoglobin in arteries (Ya) and veins (Yv). The dependence of T1a on Ya and Yv has been elegantly characterized ex vivo; however, the combined influence of pO2, Ya and Yv on T1a in vivo under normal ventilation has not been reported. Here, T1a is calculated during hyperoxia in vivo by a heuristic approach that evaluates T1 -dependent arterial spin labeling (ASL) signal changes to varying gas stimuli. Healthy volunteers (n = 14; age, 31.5 ± 7.2 years) were scanned using pseudo-continuous ASL in combination with room air (RA; 21% O2/79% N2), hypercapnic normoxic (HN; 5% CO2/21% O2/74% N2) and hypercapnic hyperoxic (HH; 5% CO2/95% O2) gas administration. HH T1a was calculated by requiring that the HN and HH cerebral blood flow (CBF) change be identical. The HH protocol was then repeated in patients (n = 10; age, 61.4 ± 13.3 years) with intracranial stenosis to assess whether an HH T1a decrease prohibited ASL from being performed in subjects with known delayed blood arrival times. Arterial blood T1a decreased from 1.65 s at baseline to 1.49 ± 0.07 s during HH. In patients, CBF values in the affected flow territory for the HH condition were increased relative to baseline CBF values and were within the physiological range (RA CBF = 36.6 ± 8.2 mL/100 g/min; HH CBF = 45.2 ± 13.9 mL/100 g/min). It can be concluded that hyperoxic (95% O2) 3-T arterial blood T1aHH = 1.49 ± 0.07 s relative to a normoxic T1a of 1.65 s. PMID:26419505

  11. Dynamic 1H NMR Studies of Schiff Base Derivatives

    NASA Astrophysics Data System (ADS)

    Köylü, M. Z.; Ekinci, A.; Böyükata, M.; Temel, H.

    2016-01-01

    The spin-lattice relaxation time T 1 and the spin-spin relaxation time T 2 of two Schiff base derivatives, N,N'-ethylenebis(salicylidene)-1,2-diaminoethane (H2L1) and N,N'-ethylenebis (salicylidene)-1,3-diaminopropane (H2L2), in DMSO-d6 solvent were studied as a function of temperature in the range of 20-50°C using a Bruker Avance 400.132 MHz 1H NMR spectrometer. Based on the activation energy ( E a) and correlation time (τc), we believe that the Schiff base derivatives perform a molecular tumbling motion.

  12. Dose correction for post-contrast T1 mapping of the heart: the MESA study.

    PubMed

    Gai, Neville D; Sandfort, Veit; Liu, Songtao; Lima, João A C; Bluemke, David A

    2016-02-01

    Post-contrast myocardial T1 (T1(myo,c)) values have been shown to be sensitive to myocardial fibrosis. Recent studies have shown differences in results obtained from T1(myo,c) and extracellular volume fraction (ECV) with respect to percentage fibrosis. By exploring the relationship between blood plasma volume and T1(myo,c), the underlying basis for the divergence can be explained. Furthermore, dose administration based on body mass index (BMI), age and gender can mitigate the divergence in results. Inter-subject comparison of T1(myo,c) required adjustment for dose (in mmol/kg), time and glomerular filtration rate. Further adjustment for effective dose based on lean muscle mass reflected by blood/plasma volume was performed. A test case of 605 subjects from the MESA study who had undergone pre- and post-contrast T1 mapping was studied. T1(myo,c) values were compared between subjects with and without metabolic syndrome (MetS), between smoking and non-smoking subjects, and subjects with and without impaired glucose tolerance, before and after dose adjustment based on plasma volume. Comparison with ECV (which is dose independent), pre-contrast myocardial T1 and blood normalized myocardial T1 values was also performed to validate the correction. There were significant differences in T1(myo,c) (post plasma volume correction) and ECV between current and former smokers (p value 0.017 and 0.01, respectively) but not T1(myo,c) prior to correction (p = 0.12). Prior to dose adjustment for plasma volume, p value was <0.001 for T1(myo,c) between MetS and non-MetS groups and was 0.13 between subjects with and without glucose intolerance; after adjustment for PV, p value was 0.63 and 0.99. Corresponding ECV p values were 0.44 and 0.99, respectively. Overall, ECV results showed the best agreement with PV corrected T1(myo,c) (mean absolute difference in p values = 0.073) and pre-contrast myocardial T1 in comparison with other measures (T1(myo,c( prior to correction, blood/plasma T1

  13. Hyperpolarized (129)Xe T (1) in oxygenated and deoxygenated blood

    NASA Technical Reports Server (NTRS)

    Albert, M. S.; Balamore, D.; Kacher, D. F.; Venkatesh, A. K.; Jolesz, F. A.

    2000-01-01

    The viability of the new technique of hyperpolarized (129)Xe MRI (HypX-MRI) for imaging organs other than the lungs depends on whether the spin-lattice relaxation time, T(1), of (129)Xe is sufficiently long in the blood. In previous experiments by the authors, the T(1) was found to be strongly dependent upon the oxygenation of the blood, with T(1) increasing from about 3 s in deoxygenated samples to about 10 s in oxygenated samples. Contrarily, Tseng et al. (J. Magn. Reson. 1997; 126: 79-86) reported extremely long T(1) values deduced from an indirect experiment in which hyperpolarized (129)Xe was used to create a 'blood-foam'. They found that oxygenation decreased T(1). Pivotal to their experiment is the continual and rapid exchange of hyperpolarized (129)Xe between the gas phase (within blood-foam bubbles) and the dissolved phase (in the skin of the bubbles); this necessitated a complicated analysis to extract the T(1) of (129)Xe in blood. In the present study, the experimental design minimizes gas exchange after the initial bolus of hyperpolarized (129)Xe has been bubbled through the sample. This study confirms that oxygenation increases the T(1) of (129)Xe in blood, from about 4 s in freshly drawn venous blood, to about 13 s in blood oxygenated to arterial levels, and also shifts the red blood cell resonance to higher frequency. Copyright 2000 John Wiley & Sons, Ltd. Abbreviations used BOLD blood oxygen level dependent NOE nuclear overhouses effect PO(2) oxygen partial pressure RBC red blood cells RF radio frequency SNR signal-to-noise ratio.

  14. Deconvolution of Compartmental Water Diffusion Coefficients in Yeast-Cell Suspensions Using Combined T1 and Diffusion Measurements

    NASA Astrophysics Data System (ADS)

    Silva, Matthew D.; Helmer, Karl G.; Lee, Jing-Huei; Han, Sam S.; Springer, Charles S.; Sotak, Christopher H.

    2002-05-01

    An NMR method is presented for measuring compartment-specific water diffusion coefficient (D) values. It uses relaxography, employing an extracellular contrast reagent (CR) to distinguish intracellular (IC) and extracellular (EC) 1H2O signals by differences in their respective longitudinal (T1) relaxation times. A diffusion-weighted inversion-recovery spin-echo (DW-IRSE) pulse sequence was used to acquire IR data sets with systematically and independently varying inversion time (TI) and diffusion-attenuation gradient amplitude (g) values. Implementation of the DW-IRSE technique was demonstrated and validated using yeast cells suspended in 3 mM Gd-DTPA2- with a wet/dry mass ratio of 3.25:1.0. Two-dimensional (2D) NMR data were acquired at 2.0 T and analyzed using numerical inverse Laplace transformation (2D- and sequential 1D-ILT) and sequential exponential fitting to yield T1 and water D values. All three methods gave substantial agreement. Exponential fitting, deemed the most accurate and time efficient, yielded T1:D (relative contribution) values of 304 ms:0.023×10-5 cm2/s (47%) and 65 ms:1.24×10-5 cm2/s (53%) for the IC and EC components, respectively. The compartment-specific D values derived from direct biexponential fitting of diffusion-attenuation data were also in good agreement. Extension of the DW-IRSE method to in vivo models should provide valuable insights into compartment-specific water D changes in response to injury or disease.

  15. Magnetic resonance imaging of brain tumors: measurement of T1: work in progress

    SciTech Connect

    Araki, T.; Inouye, T.; Suzuki, H.; Machida, T.; Iio, M.

    1984-01-01

    Longitudinal relaxation times (T1) of 20 brain tumors were calculated in vivo using a whole-body magnetic resonance unit with a 0.15-T resistive magnet. Images employing standard inversion recovery pulse sequences with different intervals between the 180)2) pulse and selective excitation pulses were compared on every point of the 256 x 256 pixel matrix. Tumor, white matter, and gray matter were sampled from each patient from the computed T1 image for T1 measurement. Astrocytomas, neurinomas, and metastatic tumors showed longer T1 values than did meningiomas. Lipomas had the shortest T1s. It is concluded that it is difficult to predict histological types of brain tumors by the measurement of T1 alone because of the wide variation in relaxation times, but measurement of T1 can be helpful in differentiating brain tumors when additional information about the patient's condition is known.

  16. New pulse sequences for T1- and T1/T2-contrast enhancing in NMR imaging.

    PubMed

    Andreev, N K; Hakimov, A M; Idiyatullin, D S

    1998-10-01

    Improved pulse sequences DIFN (abbreviation of the words: DIFferentiation by N pulses), 90 degrees - tau1 - 180 degrees tau1 - . . . 180 degrees - tau1 with optimised time intervals tau1- for T1 measurement and contrast enhancing in NMR imaging are presented. The pulse sequences DIFN have a better sensitivity to T1 than the well-known pulse sequence SR. In contrast to the IR pulse sequence, the information given by the DIFN pulse sequence is more reliable, because the NMR signal does not change its sign. For a given time interval tau0 < or = (0.1 - 0.3) T(1) the DIFN pulse sequences serve as T1-filters. They pass the signal components with relatively short T1 < T(1) and suppress the components with relatively long T1 < T(1). The effects of the radiofrequency field inhomogeneity and inaccurate adjusting of pulse lengths are also considered. It is also proposed in this work to use the joint T1T2-contrast in NMR imaging obtained as a result of applying the DIFN pulse sequences in combination with the well-known Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence. The region of interest, where the contrast should be especially enhanced, is specified by the two times at which measurements are performed, which allow the amplitudes of pixels to reach some defined levels by spin-lattice and spin-spin relaxation. PMID:9814781

  17. Advanced Colloids Experiment (ACE-T1)

    NASA Technical Reports Server (NTRS)

    Meyer, William V.; Sicker, Ron; Brown, Dan; Eustace, John

    2015-01-01

    Increment 45 - 46 Science Symposium presentation of Advanced Colloids Experiment (ACE-T1) to RPO. The purpose of this event is for Principal Investigators to present their science objectives, testing approach, and measurement methods to agency scientists, managers, and other investigators.

  18. Functional Lung MRI in Chronic Obstructive Pulmonary Disease: Comparison of T1 Mapping, Oxygen-Enhanced T1 Mapping and Dynamic Contrast Enhanced Perfusion

    PubMed Central

    Jobst, Bertram J.; Triphan, Simon M. F.; Sedlaczek, Oliver; Anjorin, Angela; Kauczor, Hans Ulrich; Biederer, Jürgen; Ley-Zaporozhan, Julia; Ley, Sebastian; Wielpütz, Mark O.

    2015-01-01

    Purpose Monitoring of regional lung function in interventional COPD trials requires alternative endpoints beyond global parameters such as FEV1. T1 relaxation times of the lung might allow to draw conclusions on tissue composition, blood volume and oxygen fraction. The aim of this study was to evaluate the potential value of lung Magnetic resonance imaging (MRI) with native and oxygen-enhanced T1 mapping for the assessment of COPD patients in comparison with contrast enhanced perfusion MRI. Materials and Methods 20 COPD patients (GOLD I-IV) underwent a coronal 2-dimensional inversion recovery snapshot flash sequence (8 slices/lung) at room air and during inhalation of pure oxygen, as well as dynamic contrast-enhanced first-pass perfusion imaging. Regional distribution of T1 at room air (T1), oxygen-induced T1 shortening (ΔT1) and peak enhancement were rated by 2 chest radiologists in consensus using a semi-quantitative 3-point scale in a zone-based approach. Results Abnormal T1 and ΔT1 were highly prevalent in the patient cohort. T1 and ΔT1 correlated positively with perfusion abnormalities (r = 0.81 and r = 0.80; p&0.001), and with each other (r = 0.80; p<0.001). In GOLD stages I and II ΔT1 was normal in 16/29 lung zones with mildly abnormal perfusion (15/16 with abnormal T1). The extent of T1 (r = 0.45; p<0.05), ΔT1 (r = 0.52; p<0.05) and perfusion abnormalities (r = 0.52; p<0.05) showed a moderate correlation with GOLD stage. Conclusion Native and oxygen-enhanced T1 mapping correlated with lung perfusion deficits and severity of COPD. Under the assumption that T1 at room air correlates with the regional pulmonary blood pool and that oxygen-enhanced T1 reflects lung ventilation, both techniques in combination are principally suitable to characterize ventilation-perfusion imbalance. This appears valuable for the assessment of regional lung characteristics in COPD trials without administration of i.v. contrast. PMID:25822195

  19. 1H NMR relaxation in urea

    NASA Astrophysics Data System (ADS)

    Taylor, R. E.; Bacher, Alfred D.; Dybowski, C.

    2007-11-01

    Proton NMR spin-lattice relaxation times T1 were measured for urea as a function of temperature. An activation energy of 46.3 ± 4.7 kJ/mol was extracted and compared with the range of 38-65 kJ/mol previously reported in the literature as measured by different magnetic resonance techniques. In addition, proton NMR spin-lattice relaxation times in the rotating frame T1 ρ were measured as a function of temperature. These measurements provide acquisition conditions for the 13C and 15N CP/MAS spectra of pure urea in the crystalline phase.

  20. Distinct Human and Mouse Membrane Trafficking Systems for Sweet Taste Receptors T1r2 and T1r3

    PubMed Central

    Shimizu, Madoka; Goto, Masao; Kawai, Takayuki; Yamashita, Atsuko; Kusakabe, Yuko

    2014-01-01

    The sweet taste receptors T1r2 and T1r3 are included in the T1r taste receptor family that belongs to class C of the G protein-coupled receptors. Heterodimerization of T1r2 and T1r3 is required for the perception of sweet substances, but little is known about the mechanisms underlying this heterodimerization, including membrane trafficking. We developed tagged mouse T1r2 and T1r3, and human T1R2 and T1R3 and evaluated membrane trafficking in human embryonic kidney 293 (HEK293) cells. We found that human T1R3 surface expression was only observed when human T1R3 was coexpressed with human T1R2, whereas mouse T1r3 was expressed without mouse T1r2 expression. A domain-swapped chimera and truncated human T1R3 mutant showed that the Venus flytrap module and cysteine-rich domain (CRD) of human T1R3 contain a region related to the inhibition of human T1R3 membrane trafficking and coordinated regulation of human T1R3 membrane trafficking. We also found that the Venus flytrap module of both human T1R2 and T1R3 are needed for membrane trafficking, suggesting that the coexpression of human T1R2 and T1R3 is required for this event. These results suggest that the Venus flytrap module and CRD receive taste substances and play roles in membrane trafficking of human T1R2 and T1R3. These features are different from those of mouse receptors, indicating that human T1R2 and T1R3 are likely to have a novel membrane trafficking system. PMID:25029362

  1. Reduced Right Ventricular Native Myocardial T1 in Anderson-Fabry Disease: Comparison to Pulmonary Hypertension and Healthy Controls

    PubMed Central

    Pagano, Joseph J.; Chow, Kelvin; Khan, Aneal; Michelakis, Evangelos; Paterson, Ian; Oudit, Gavin Y.; Thompson, Richard B.

    2016-01-01

    Aims Anderson-Fabry disease (AFD) is characterized by progressive multiorgan accumulation of intracellular sphingolipids due to α-galactosidase A enzyme deficiency, resulting in progressive ventricular hypertrophy, heart failure, arrhythmias, and death. Decreased native (non-contrast) left ventricular (LV) T1 (longitudinal relaxation time) with MRI discriminates AFD from healthy controls or other presentations of concentric hypertrophy, but the right ventricle (RV) has not been studied. The aims of the current study were to evaluate native RV T1 values in AFD, with a goal of better understanding the pathophysiology of RV involvement. Methods and Results Native T1 values were measured in the inferior RV wall (RVI), interventricular septum (IVS), and inferior LV (LVI) in patients with AFD, patients with pulmonary hypertension, who provided an alternative RV pathological process for comparison, and healthy controls. A minimum wall thickness of 4 mm was selected to minimize partial volume errors in tissue T1 analysis. T1 analysis was performed in 6 subjects with AFD, 6 subjects with PH, and 21 controls. Native T1 values were shorter (adjusted p<0.05 for all comparisons), independent of location, in subjects with AFD (RVI-T1 = 1096±49 ms, IVS-T1 = 1053±41 ms, LVI-T1 = 1072±44 ms) compared to both PH (RVI-T1 = 1239±41 ms, IVS-T1 = 1280±123 ms, LVI-T1 = 1274±57 ms) and HC (IVS-T1 = 1180±60 ms, LVI-T1 = 1183±45 ms). RVI measurements were not possible in controls due to insufficient wall thickness. Conclusion Native T1 values appear similarly reduced in the left and right ventricles of individuals with AFD and RV wall thickening, suggesting a common pathology. In contrast, individuals with PH and thickened RVs showed increased native T1 values in both ventricles, suggestive of fibrosis. PMID:27305064

  2. Native T1 Mapping of the Heart – A Pictorial Review

    PubMed Central

    Germain, Philippe; El Ghannudi, Soraya; Jeung, Mi-Young; Ohlmann, Patrick; Epailly, Eric; Roy, Catherine; Gangi, Afshin

    2014-01-01

    T1 mapping is now a clinically feasible method, providing pixel-wise quantification of the cardiac structure’s T1 values. Beyond focal lesions, well depicted by late gadolinium enhancement sequences, it has become possible to discriminate diffuse myocardial alterations, previously not assessable by noninvasive means. The strength of this method includes the high reproducibility and immediate clinical applicability, even without the use of contrast media injection (native or pre-contrast T1). The two most important determinants of native T1 augmentation are (1) edema related to tissue water increase (recent infarction or inflammation) and (2) interstitial space increase related to fibrosis (infarction scar, cardiomyopathy) or to amyloidosis. Conversely, lipid (Anderson–Fabry) or iron overload diseases are responsible for T1 reduction. In this pictorial review, the main features provided by native T1 mapping are discussed and illustrated, with a special focus on the awaited clinical purpose of this unique, promising new method. PMID:25525401

  3. Measurement of T1 of human arterial and venous blood at 7T

    PubMed Central

    Rane, S.; Gore, J.C.

    2012-01-01

    Techniques for measuring cerebral perfusion require accurate longitudinal relaxation (T1) of blood, a MRI parameter that is field dependent. T1 of arterial and venous human blood was measured at 7T using three different sources – pathology laboratory, blood bank and in vivo. The T1 of venous blood was measured from sealed samples from a pathology lab and in vivo. Samples from a blood bank were oxygenated and mixed to obtain different physiological concentrations of hematocrit and oxygenation. T1 relaxation times were estimated using a three-point fit to a simple inversion recovery equation. At 37° C, the T1 of blood at arterial pO2was 2.29 ± 0.1 s and 2.07 ± 0.12 at venous pO2. The in vivo T1 of venous blood, in three subjects, was slightly longer at 2.45 ± 0.11s. T1 of arterial and venous blood at 7T was measured and found to be significantly different. The T1 values were longer in vivo than in vitro. While the exact cause for the discrepancy is unknown, the additives in the blood samples, degradation during experiment, oxygenation differences, and the non-stagnant nature of blood in vivo could be potential contributors to the lower values of T1 in the venous samples. PMID:23102945

  4. 1H NMR spectra part 31: 1H chemical shifts of amides in DMSO solvent.

    PubMed

    Abraham, Raymond J; Griffiths, Lee; Perez, Manuel

    2014-07-01

    The (1)H chemical shifts of 48 amides in DMSO solvent are assigned and presented. The solvent shifts Δδ (DMSO-CDCl3 ) are large (1-2 ppm) for the NH protons but smaller and negative (-0.1 to -0.2 ppm) for close range protons. A selection of the observed solvent shifts is compared with calculated shifts from the present model and from GIAO calculations. Those for the NH protons agree with both calculations, but other solvent shifts such as Δδ(CHO) are not well reproduced by the GIAO calculations. The (1)H chemical shifts of the amides in DMSO were analysed using a functional approach for near ( ≤ 3 bonds removed) protons and the electric field, magnetic anisotropy and steric effect of the amide group for more distant protons. The chemical shifts of the NH protons of acetanilide and benzamide vary linearly with the π density on the αN and βC atoms, respectively. The C=O anisotropy and steric effect are in general little changed from the values in CDCl3. The effects of substituents F, Cl, Me on the NH proton shifts are reproduced. The electric field coefficient for the protons in DMSO is 90% of that in CDCl3. There is no steric effect of the C=O oxygen on the NH proton in an NH…O=C hydrogen bond. The observed deshielding is due to the electric field effect. The calculated chemical shifts agree well with the observed shifts (RMS error of 0.106 ppm for the data set of 257 entries). PMID:24824670

  5. Relaxation of water protons in highly concentrated aqueous protein systems studied by 1H NMR spectroscopy.

    PubMed

    Szuminska, K; Gutsze, A; Kowalczyk, A

    2001-01-01

    Concentrated Aqueous Protein Systems, Proton Relaxation Times, Slow Chemical Exchange In this paper we present proton spin-lattice (T1) and spin-spin (T2) relaxation times measured vs. concentration, temperature, pulse interval (tauCPMG) as well as 1H NMR spectral measurements in a wide range of concentrations of bovine serum albumin (BSA) solutions. The anomalous relaxation behaviour of the water protons, similar to that observed in mammalian lenses, was found in the two most concentrated solutions (44% and 46%). The functional dependence of the spin-spin relaxation time vs. tauCPMG pulse interval and the values of the motional activation parameters obtained from the temperature dependencies of spin-lattice relaxation times suggest that the water molecule mobility is reduced in these systems. The slow exchange process on the T2 time scale is proposed to explain the obtained data. The proton spectral measurements support the hypothesis of a slow exchange mechanism in the highest concentrated solutions. From the analysis of the shape of the proton spectra the mean exchange times between bound and bulk water proton groups (tauex) have been estimated for the range of the highest concentrations (30%-46%). The obtained values are of the order of milliseconds assuring that the slow exchange condition is fulfilled in the most concentrated samples. PMID:11837660

  6. The guest ordering and dynamics in urea inclusion compounds studied by solid-state 1H and 13C MAS NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Yang, Xiaorong; Müller, Klaus

    2011-12-01

    Urea inclusion compounds with different guest species were studied by 13C CP MAS and 1H MAS NMR spectroscopy. It is possible to arrange the asymmetric guest species in three different ways: head-head, head-tail and tail-tail. 13C CP MAS NMR studies indicate that the preference arrangement is determined by the interaction strength of the end functional groups. 13C relaxation experiments are used to study the dynamic properties of urea inclusion compounds. 13C relaxation studies on urea inclusion compounds with n-alkane or decanoic acid show that the 13C T1 and 13C T1ρ values exhibit the position dependence towards the center of the chain, indicating internal chain mobility. The analysis of variable-temperature 13C T1ρ experiments on urea inclusion compounds with hexadecane and pentadecane, for the first time, suggests that chain fluctuations and lateral motion of n-alkane guests may contribute to the 13C T1ρ relaxation.

  7. Can T1-rho MRI detect acetabular cartilage degeneration in femoroacetabular impingement?: a pilot study.

    PubMed

    Rakhra, K S; Lattanzio, P-J; Cárdenas-Blanco, A; Cameron, I G; Beaulé, P E

    2012-09-01

    Advanced MRI cartilage imaging such as T(1)-rho (T1ρ) for the diagnosis of early cartilage degradation prior to morpholgic radiological changes may provide prognostic information in the management of joint disease. This study aimed first to determine the normal T1ρ profile of cartilage within the hip, and secondly to identify any differences in T1ρ profile between the normal and symptomatic femoroacetabular impingement (FAI) hip. Ten patients with cam-type FAI (seven male and three female, mean age 35.9 years (28 to 48)) and ten control patients (four male and six female, mean age 30.6 years (22 to 35)) underwent 1.5T T1ρ MRI of a single hip. Mean T1ρ relaxation times for full thickness and each of the three equal cartilage thickness layers were calculated and compared between the groups. The mean T1ρ relaxation times for full cartilage thickness of control and FAI hips were similar (37.17 ms (SD 9.95) and 36.71 ms (SD 6.72), respectively). The control group demonstrated a T1ρ value trend, increasing from deep to superficial cartilage layers, with the middle third having significantly greater T1ρ relaxation values than the deepest third (p = 0.008). The FAI group demonstrated loss of this trend. The deepest third in the FAI group demonstrated greater T1ρ relaxation values than controls (p = 0.028). These results suggest that 1.5T T1ρ MRI can detect acetabular hyaline cartilage changes in patients with FAI. PMID:22933489

  8. Tumbling motions of NH2(CH3)2 ions in [NH2(CH3)2]2ZnCl4 studied using 1H MAS NMR and 13C CP/MAS NMR

    NASA Astrophysics Data System (ADS)

    Kim, Nam Hee; Choi, Jae Hun; Lim, Ae Ran

    2014-12-01

    The structure and the phase transition temperatures of [NH2(CH3)2]2ZnCl4 were determined using X-ray diffraction and DSC, respectively. The temperature dependence of chemical shifts and the spin-lattice relaxation time T1ρ in the rotating frame were measured for the 1H and 13C nuclei in [NH2(CH3)2]2ZnCl4. From these results, it was observed that the structural change by chemical shifts does not occur with temperature. However, T1ρ for 1H and 13C in [NH2(CH3)2]2ZnCl4 showed a minimum, and it is apparent that both T1ρ values are governed by the same tumbling motions. The activation energies of tumbling motions for 1H and 13C are nearly the same owing to the connection between CH3 and NH2 ions in the [NH2(CH3)2]+ group.

  9. Enhanced Y1H Assays for Arabidopis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transcription regulation plays a key role in development and response to environment. To understand this mechanism, we need to know which transcription factor (TFs) would bind to which promoter, thus regulate their target gene expression. Yeast one-hybrid (Y1H) technique can be used to map this kind...

  10. T1 Mapping in Characterizing Myocardial Disease: A Comprehensive Review.

    PubMed

    Puntmann, Valentina O; Peker, Elif; Chandrashekhar, Y; Nagel, Eike

    2016-07-01

    Cardiovascular magnetic resonance provides insights into myocardial structure and function noninvasively, with high diagnostic accuracy and without ionizing radiation. Myocardial tissue characterization in particular gives cardiovascular magnetic resonance a prime role among all the noninvasive cardiovascular investigations. Late gadolinium enhancement imaging is an established method for visualizing replacement scar, providing diagnostic and prognostic information in a variety of cardiac conditions. Late gadolinium enhancement, however, relies on the regional segregation of tissue characteristics to generate the imaging contrast. Thus, myocardial pathology that is diffuse in nature and affecting the myocardium in a rather uniform and global distribution is not well visualized with late gadolinium enhancement. Examples include diffuse myocardial inflammation, fibrosis, hypertrophy, and infiltration. T1 mapping is a novel technique allowing to diagnose these diffuse conditions by measurement of T1 values, which directly correspond to variation in intrinsic myocardial tissue properties. In addition to providing clinically meaningful indices, T1-mapping measurements also allow for an estimation of extracellular space by calculation of extracellular volume fraction. Multiple lines of evidence suggest a central role for T1 mapping in detection of diffuse myocardial disease in early disease stages and complements late gadolinium enhancement in visualization of the regional changes in common advanced myocardial disease. As a quantifiable measure, it may allow grading of disease activity, monitoring progress, and guiding treatment, potentially as a fast contrast-free clinical application. We present an overview of clinically relevant technical aspects of acquisition and processing, and the current state of art and evidence, supporting its clinical use. PMID:27390332

  11. Native Magnetic Resonance T1-Mapping Identifies Diffuse Myocardial Injury in Hypothyroidism

    PubMed Central

    Qu, Aijuan; Chen, Zhe; Jia, Yumei; Yang, Ning; Feng, Xiaomeng; Liu, Jia; Xu, Yuan; Yang, Xinchun; Wang, Guang

    2016-01-01

    Background and Aim Hypothyroidism (HT) is characterized by thyroid hormone deficiencies, which can lead to diffuse myocardial interstitium lesions in patients with HT. Myocardial longitudinal relaxation time (T1) mapping is a potential diagnostic tool for quantifying diffuse myocardial injury. This study aimed to assess the usefulness of T1 mapping in identifying myocardial involvement in HT, and determine the relationship between T1 values and myocardial function. Methods A cross-sectional study was conducted with 30 untreated HT patients alongside 23 age- and sex-matched healthy controls. All subjects underwent cardiac magnetic resonance (CMR) with non-contrast (native) T1 mapping using a modified Look-Locker inversion-recovery (MOLLI) sequence to assess the native T1 values of myocardium and cardiac function. Results Native myocardial T1 values were significantly increased in HT patients, especially those with pericardial effusion (p < 0.05), compared with healthy controls. In addition, significantly reduced peak filling rate (PFR) and prolonged peak filling time (PFT) were obtained (p < 0.05) in HT patients compared with controls. Furthermore, stroke volume (SV) and cardiac index (CI) were significantly lower in HT patients than controls (all p < 0.05). Interestingly, native T1 values were negatively correlated with free triiodothyronine (FT3), PFR, SV and CI (all p < 0.05). Conclusion Diffuse myocardial injuries are common in HT patients, and increased T1 values are correlated with FT3 and cardiac function impairment. These findings indicate that T1 mapping might be useful in evaluating myocardial injuries in HT patients. PMID:26964099

  12. Molecular Dynamics Simulation and Experimental Verification of the Interaction between Cyclin T1 and HIV-1 Tat Proteins

    PubMed Central

    Asamitsu, Kaori; Hibi, Yurina

    2015-01-01

    The viral encoded Tat protein is essential for the transcriptional activation of HIV proviral DNA. Interaction of Tat with a cellular transcription elongation factor P-TEFb containing CycT1 is critically required for its action. In this study, we performed MD simulation using the 3D data for wild-type and 4CycT1mutants3D data. We found that the dynamic structural change of CycT1 H2’ helix is indispensable for its activity for the Tat action. Moreover, we detected flexible structural changes of the Tat-recognition cavity in the WT CycT1 comprising of ten AAs that are in contact with Tat. These structural fluctuations in WT were lost in the CycT1 mutants. We also found the critical importance of the hydrogen bond network involving H1, H1’ and H2 helices of CycT1. Since similar AA substitutions of the Tat-CycT1 chimera retained the Tat-supporting activity, these interactions are considered primarily involved in interaction with Tat. These findings described in this paper should provide vital information for the development of effective anti-Tat compound. PMID:25781978

  13. Molecular dynamics simulation and experimental verification of the interaction between cyclin T1 and HIV-1 Tat proteins.

    PubMed

    Asamitsu, Kaori; Hirokawa, Takatsugu; Hibi, Yurina; Okamoto, Takashi

    2015-01-01

    The viral encoded Tat protein is essential for the transcriptional activation of HIV proviral DNA. Interaction of Tat with a cellular transcription elongation factor P-TEFb containing CycT1 is critically required for its action. In this study, we performed MD simulation using the 3D data for wild-type and 4CycT1mutants3D data. We found that the dynamic structural change of CycT1 H2' helix is indispensable for its activity for the Tat action. Moreover, we detected flexible structural changes of the Tat-recognition cavity in the WT CycT1 comprising of ten AAs that are in contact with Tat. These structural fluctuations in WT were lost in the CycT1 mutants. We also found the critical importance of the hydrogen bond network involving H1, H1' and H2 helices of CycT1. Since similar AA substitutions of the Tat-CycT1 chimera retained the Tat-supporting activity, these interactions are considered primarily involved in interaction with Tat. These findings described in this paper should provide vital information for the development of effective anti-Tat compound. PMID:25781978

  14. Conformation analysis and molecular mobility of ethylene and tetrafluoroethylene copolymer using solid-state 19F MAS and 1H --> 19F CP/MAS NMR spectroscopy.

    PubMed

    Aimi, Keitaro; Ando, Shinji

    2004-07-01

    The changes in the conformation and molecular mobility accompanied by a phase transition in the crystalline domain were analyzed for ethylene (E) and tetrafluoroethylene (TFE) copolymer, ETFE, using variable-temperature (VT) solid-state 19F magic angle spinning (MAS) and 1H --> 19F cross-polarization (CP)/MAS NMR spectroscopy. The shifts of the signals for fluorines in TFE units to higher frequency and the continuing decrease and increase in the T1rho(F) values suggest that conformational exchange motions exist in the crystalline domain between 42 and 145 degrees C. Quantum chemical calculations of magnetic shielding constants showed that the high-frequency shift of TFE units should be induced by trans to gauche conformational changes at the CH2-CF2 linkage in the E-TFE unit. Although the 19F signals of the crystalline domain are substantially overlapped with those of the amorphous domain at ambient probe temperature (68 degrees C), they were successfully distinguished by using the dipolar filter and spin-lock pulse sequences at 145 degrees C. The dipolar coupling constants for the crystalline domain, which can be estimated by fitting the dipolar oscillation behaviors in the 1H --> 19F CP curve, showed a significant decrease with increasing temperature from 42 to 145 degrees C. This is due to the averaging of 1H-19F dipolar interactions originating from the molecular motion in the crystalline domain. The increase in molecular mobility in the crystalline domain was clearly shown by VT T1rho(F) and 1H --> 19F CP measurements in the phase transition temperature range. PMID:15181627

  15. Model-Based Acceleration of Look-Locker T1 Mapping

    PubMed Central

    Tran-Gia, Johannes; Wech, Tobias; Bley, Thorsten; Köstler, Herbert

    2015-01-01

    Mapping the longitudinal relaxation time T1 has widespread applications in clinical MRI as it promises a quantitative comparison of tissue properties across subjects and scanners. Due to the long scan times of conventional methods, however, the use of quantitative MRI in clinical routine is still very limited. In this work, an acceleration of Inversion-Recovery Look-Locker (IR-LL) T1 mapping is presented. A model-based algorithm is used to iteratively enforce an exponential relaxation model to a highly undersampled radially acquired IR-LL dataset obtained after the application of a single global inversion pulse. Using the proposed technique, a T1 map of a single slice with 1.6mm in-plane resolution and 4mm slice thickness can be reconstructed from data acquired in only 6s. A time-consuming segmented IR experiment was used as gold standard for T1 mapping in this work. In the subsequent validation study, the model-based reconstruction of a single-inversion IR-LL dataset exhibited a T1 difference of less than 2.6% compared to the segmented IR-LL reference in a phantom consisting of vials with T1 values between 200ms and 3000ms. In vivo, the T1 difference was smaller than 5.5% in WM and GM of seven healthy volunteers. Additionally, the T1 values are comparable to standard literature values. Despite the high acceleration, all model-based reconstructions were of a visual quality comparable to fully sampled references. Finally, the reproducibility of the T1 mapping method was demonstrated in repeated acquisitions. In conclusion, the presented approach represents a promising way for fast and accurate T1 mapping using radial IR-LL acquisitions without the need of any segmentation. PMID:25860381

  16. T1- Thresholds in Black Holes Increase Clinical-Radiological Correlation in Multiple Sclerosis Patients

    PubMed Central

    Thaler, Christian; Faizy, Tobias; Sedlacik, Jan; Holst, Brigitte; Stellmann, Jan-Patrick; Young, Kim Lea; Heesen, Christoph; Fiehler, Jens; Siemonsen, Susanne

    2015-01-01

    Background Magnetic Resonance Imaging (MRI) is an established tool in diagnosing and evaluating disease activity in Multiple Sclerosis (MS). While clinical-radiological correlations are limited in general, hypointense T1 lesions (also known as Black Holes (BH)) have shown some promising results. The definition of BHs is very heterogeneous and depends on subjective visual evaluation. Objective We aimed to improve clinical-radiological correlations by defining BHs using T1 relaxation time (T1-RT) thresholds to achieve best possible correlation between BH lesion volume and clinical disability. Method 40 patients with mainly relapsing-remitting MS underwent MRI including 3-dimensional fluid attenuated inversion recovery (FLAIR), magnetization-prepared rapid gradient echo (MPRAGE) before and after Gadolinium (GD) injection and double inversion-contrast magnetization-prepared rapid gradient echo (MP2RAGE) sequences. BHs (BHvis) were marked by two raters on native T1-weighted (T1w)-MPRAGE, contrast-enhancing lesions (CE lesions) on T1w-MPRAGE after GD and FLAIR lesions (total-FLAIR lesions) were detected separately. BHvis and total-FLAIR lesion maps were registered to MP2RAGE images, and the mean T1-RT were calculated for all lesion ROIs. Mean T1 values of the cortex (CTX) were calculated for each patient. Subsequently, Spearman rank correlations between clinical scores (Expanded Disability Status Scale and Multiple Sclerosis Functional Composite) and lesion volume were determined for different T1-RT thresholds. Results Significant differences in T1-RT were obtained between all different lesion types with highest T1 values in visually marked BHs (BHvis: 1453.3±213.4 ms, total-FLAIR lesions: 1394.33±187.38 ms, CTX: 1305.6±35.8 ms; p<0.05). Significant correlations between BHvis/total-FLAIR lesion volume and clinical disability were obtained for a wide range of T1-RT thresholds. The highest correlation for BHvis and total-FLAIR lesion masks were found at T1-RT>1500 ms

  17. Orosensory detection of sucrose, maltose, and glucose is severely impaired in mice lacking T1R2 or T1R3, but Polycose sensitivity remains relatively normal.

    PubMed

    Treesukosol, Yada; Spector, Alan C

    2012-07-15

    Evidence in the literature supports the hypothesis that the T1R2+3 heterodimer binds to compounds that humans describe as sweet. Here, we assessed the necessity of the T1R2 and T1R3 subunits in the maintenance of normal taste sensitivity to carbohydrate stimuli. We trained and tested water-restricted T1R2 knockout (KO), T1R3 KO and their wild-type (WT) same-sex littermate controls in a two-response operant procedure to sample a fluid and differentially respond on the basis of whether the stimulus was water or a tastant. Correct responses were reinforced with water and incorrect responses were punished with a time-out. Testing was conducted with a modified descending method of limits procedure across daily 25-min sessions. Both KO groups displayed severely impaired performance and markedly decreased sensitivity when required to discriminate water from sucrose, glucose, or maltose. In contrast, when Polycose was tested, KO mice had normal EC(50) values for their psychometric functions, with some slight, but significant, impairment in performance. Sensitivity to NaCl did not differ between these mice and their WT controls. Our findings support the view that the T1R2+3 heterodimer is the principal receptor that mediates taste detection of natural sweeteners, but not of all carbohydrate stimuli. The combined presence of T1R2 and T1R3 appears unnecessary for the maintenance of relatively normal sensitivity to Polycose, at least in this task. Some detectability of sugars at high concentrations might be mediated by the putative polysaccharide taste receptor, the remaining T1R subunit forming either a homodimer or heteromer with another protein(s), or nontaste orosensory cues. PMID:22621968

  18. Quantitative 1H MRI and MRS Microscopy of Individual V79 Lung Tumor Spheroids

    NASA Astrophysics Data System (ADS)

    Minard, Kevin R.; Guo, Xiuling; Wind, Robert A.

    1998-08-01

    In this Communication1H MRI and MRS microscopy experiments of individual V79 lung tumor spheroids with diameters between 550 and 650 μm are reported. The results have been used to determine theT1,T2, andDvalues as well as the concentrations of water, total choline, creatine/phosphocreatine, and mobile lipids in the viable rims and in the necrotic centers.

  19. Direct reconstruction of T1 from k-space using a radial saturation-recovery sequence

    NASA Astrophysics Data System (ADS)

    Chen, Liyong; DiBella, Edward V. R.

    2011-03-01

    Contrast agent concentration ([CA]) must be known accurately to quantify dynamic contrast-enhanced (DCE) MR imaging. Accurate concentrations can be obtained if the longitudinal relaxation rate constant T1 is known both pre- and post-contrast injection. Post-contrast signal intensity in the images is often saturated and an approximation to T1 can be difficult to obtain. One method that has been proposed for accurate T1 estimation effectively acquires multiple images with different effective saturation recovery times (eSRTs) and fits the images to the equation for T1 recovery to obtain T1 values. This was done with a radial saturation-recovery sequence for 2D imaging of myocardial perfusion with DCE MRI. This multi-SRT method assumes that the signal intensity is constant for different readouts in each image. Here this assumption is not necessary as a model-based reconstruction method is proposed that directly reconstructs an image of T1 values from k-space. The magnetization for each ray at each readout pulse is modeled in the reconstruction with Bloch equations. Computer simulations based on a 72 ray cardiac DCE MRI acquisition were used to test the method. The direct model-based reconstruction gave accurate T1 values and was slightly more accurate than the multi-SRT method that used three sub-images.

  20. T 1 Relaxation Measurement of Ex-Vivo Breast Cancer Tissues at Ultralow Magnetic Fields

    PubMed Central

    Lee, Seong-Joo; Shim, Jeong Hyun; Kim, Kiwoong; Hwang, Seong-min; Yu, Kwon Kyu; Lim, Sanghyun; Han, Jae Ho; Yim, Hyunee; Kim, Jang-Hee; Jung, Yong Sik; Kim, Ku Sang

    2015-01-01

    We investigated T1 relaxations of ex-vivo cancer tissues at low magnetic fields in order to check the possibility of achieving a T1 contrast higher than those obtained at high fields. The T1 relaxations of fifteen pairs (normal and cancerous) of breast tissue samples were measured at three magnetic fields, 37, 62, and 122 μT, using our superconducting quantum interference device-based ultralow field nuclear magnetic resonance setup, optimally developed for ex-vivo tissue studies. A signal reconstruction based on Bayesian statistics for noise reduction was exploited to overcome the low signal-to-noise ratio. The ductal and lobular-type tissues did not exhibit meaningful T1 contrast values between normal and cancerous tissues at the three different fields. On the other hand, an enhanced T1 contrast was obtained for the mucinous cancer tissue. PMID:25705658

  1. Serial changes in the T1 magnetic relaxation parameter after myocardial infarction in man.

    PubMed Central

    Been, M; Smith, M A; Ridgway, J P; Douglas, R H; de Bono, D P; Best, J J; Muir, A L

    1988-01-01

    A low field resistive nuclear magnetic resonance imaging system (0.08 Tesla) was used to study the in vivo changes in the relaxation parameter T1 of the left ventricular myocardium from the first day to six months after acute myocardial infarction in 41 consecutive patients admitted to a coronary care unit. T1 maps were constructed from transverse and coronal images at various times after infarction. Thrombolytic treatment had been successful in 28 patients. Thirty three of the 34 patients studied within two weeks of infarction had a significantly increased T1 value but this developed only after the third day in four. At day 1-3 the mean (1 SD) maximum T1 was 413 (29) ms (n = 23) compared with 430 (41) ms (n = 22) at day 4-7, 433 (35) ms (n = 24) at day 8-14, 420 (34) at one month (n = 22), 388 (39) (n = 20) at three months, and 361 (24) (n = 14) at six months. The number of regions of interest with an increased T1 followed a similar time course. Although the increase in T1 measured at three months correlated with the initial maximum creatine kinase and with the left ventricular ejection fraction measured at one month, the number of regions with abnormal T1 from day 4 through to one month correlated best with left ventricular ejection fraction. There was no significant difference in T1 between patients with or without reperfusion. The rise in T1 over the first few days together with the prolonged time course of T1 increase suggests that the increase in T1 may reflect cellular infiltration as much or more than tissue oedema. Images Fig 3 PMID:3342143

  2. Improving Assessment of Lipoprotein Profile in Type 1 Diabetes by 1H NMR Spectroscopy

    PubMed Central

    Brugnara, Laura; Mallol, Roger; Ribalta, Josep; Vinaixa, Maria; Murillo, Serafín; Casserras, Teresa; Guardiola, Montse; Vallvé, Joan Carles; Kalko, Susana G.; Correig, Xavier; Novials, Anna

    2015-01-01

    Patients with type 1 diabetes (T1D) present increased risk of cardiovascular disease (CVD). The aim of this study is to improve the assessment of lipoprotein profile in patients with T1D by using a robust developed method 1H nuclear magnetic resonance spectroscopy (1H NMR), for further correlation with clinical factors associated to CVD. Thirty patients with T1D and 30 non-diabetes control (CT) subjects, matched for gender, age, body composition (DXA, BMI, waist/hip ratio), regular physical activity levels and cardiorespiratory capacity (VO2peak), were analyzed. Dietary records and routine lipids were assessed. Serum lipoprotein particle subfractions, particle sizes, and cholesterol and triglycerides subfractions were analyzed by 1H NMR. It was evidenced that subjects with T1D presented lower concentrations of small LDL cholesterol, medium VLDL particles, large VLDL triglycerides, and total triglycerides as compared to CT subjects. Women with T1D presented a positive association with HDL size (p<0.005; R = 0.601) and large HDL triglycerides (p<0.005; R = 0.534) and negative (p<0.005; R = -0.586) to small HDL triglycerides. Body fat composition represented an important factor independently of normal BMI, with large LDL particles presenting a positive correlation to total body fat (p<0.005; R = 0.505), and total LDL cholesterol and small LDL cholesterol a positive correlation (p<0.005; R = 0.502 and R = 0.552, respectively) to abdominal fat in T1D subjects; meanwhile, in CT subjects, body fat composition was mainly associated to HDL subclasses. VO2peak was negatively associated (p<0.005; R = -0.520) to large LDL-particles only in the group of patients with T1D. In conclusion, patients with T1D with adequate glycemic control and BMI and without chronic complications presented a more favourable lipoprotein profile as compared to control counterparts. In addition, slight alterations in BMI and/or body fat composition showed to be relevant to provoking alterations in

  3. In vivo1H NMR spectroscopy of the human brain at 9.4 T: Initial results

    NASA Astrophysics Data System (ADS)

    Deelchand, Dinesh Kumar; Moortele, Pierre-François Van de; Adriany, Gregor; Iltis, Isabelle; Andersen, Peter; Strupp, John P.; Thomas Vaughan, J.; Uğurbil, Kâmil; Henry, Pierre-Gilles

    2010-09-01

    In vivo proton NMR spectroscopy allows non-invasive detection and quantification of a wide range of biochemical compounds in the brain. Higher field strength is generally considered advantageous for spectroscopy due to increased signal-to-noise and increased spectral dispersion. So far 1H NMR spectra have been reported in the human brain up to 7 T. In this study we show that excellent quality short echo time STEAM and LASER 1H NMR spectra can be measured in the human brain at 9.4 T. The information content of the human brain spectra appears very similar to that measured in the past decade in rodent brains at the same field strength, in spite of broader linewidth in human brain. Compared to lower fields, the T1 relaxation times of metabolites were slightly longer while T2 relaxation values of metabolites were shorter (<100 ms) at 9.4 T. The linewidth of the total creatine (tCr) resonance at 3.03 ppm increased linearly with magnetic field (1.35 Hz/T from 1.5 T to 9.4 T), with a minimum achievable tCr linewidth of around 12.5 Hz at 9.4 T. At very high field, B0 microsusceptibility effects are the main contributor to the minimum achievable linewidth.

  4. Sampling submicron T1 bacteriophage aerosols.

    PubMed

    Harstad, J B

    1965-11-01

    Liquid impingers, filter papers, and fritted bubblers were partial viable collectors of radioactive submicron T1 bacteriophage aerosols at 30, 55, and 85% relative humidity. Sampler differences for viable collection were due to incomplete physical collection (slippage) and killing of phage by the samplers. Dynamic aerosols of a mass median diameter of 0.2 mu were produced with a Dautrebande generator from concentrated aqueous purified phage suspensions containing extracellular soluble radioactive phosphate as a physical tracer. There was considerable destruction of phage by the Dautrebande generator; phage titers of the Dautrebande suspension decreased exponentially, but there was a progressive (linear) increase in tracer titers. Liquid impingers recovered the most viable phage but allowed considerable (30 to 48%) slippage, which varies inversely with the aerosol relative humidity. Filter papers were virtually complete physical collectors of submicron particles but were the most destructive. Fritted bubbler slippage was more than 80%. With all samplers, phage kill was highest at 85% relative humidity and lowest at 55% relative humidity. An electrostatic precipitator was used to collect aerosol samples for particle sizing with an electron microscope. The particle size was slightly larger at 85% relative humidity than at 30 or 55% relative humidity. PMID:5866038

  5. Influence of fat on liver T 1 measurements using modified Look–Locker inversion recovery (MOLLI) methods at 3T

    PubMed Central

    Tunnicliffe, Elizabeth M.; Pavlides, Michael; Robson, Matthew D.

    2016-01-01

    Purpose To characterize the effect of fat on modified Look–Locker inversion recovery (MOLLI) T 1 maps of the liver. The balanced steady‐state free precession (bSSFP) sequence causes water and fat signals to have opposite phase when repetition time (TR) = 2.3 msec at 3T. In voxels that contain both fat and water, the MOLLI T 1 measurement is influenced by the choice of TR. Materials and Methods MOLLI T 1 measurements of the liver were simulated using the Bloch equations while varying the hepatic lipid content (HLC). Phantom scans were performed on margarine phantoms, using both MOLLI and spin echo inversion recovery sequences. MOLLI T 1 at 3T and HLC were determined in patients (n = 8) before and after bariatric surgery. Results At 3T, with HLC in the 0–35% range, higher fat fraction values lead to longer MOLLI T 1 values when TR = 2.3 msec. Patients were found to have higher MOLLI T 1 at elevated HLC (T 1 = 929 ± 97 msec) than at low HLC (T 1 = 870 ± 44 msec). Conclusion At 3T, MOLLI T 1 values are affected by HLC, substantially changing MOLLI T 1 in a clinically relevant range of fat content. J. Magn. Reson. Imaging 2016;44:105–111. PMID:26762615

  6. The 1H NMR Profile of Healthy Dog Cerebrospinal Fluid

    PubMed Central

    Musteata, Mihai; Nicolescu, Alina; Solcan, Gheorghe; Deleanu, Calin

    2013-01-01

    The availability of data for reference values in cerebrospinal fluid for healthy humans is limited due to obvious practical and ethical issues. The variability of reported values for metabolites in human cerebrospinal fluid is quite large. Dogs present great similarities with humans, including in cases of central nervous system pathologies. The paper presents the first study on healthy dog cerebrospinal fluid metabolomic profile using 1H NMR spectroscopy. A number of 13 metabolites have been identified and quantified from cerebrospinal fluid collected from a group of 10 mix breed healthy dogs. The biological variability as resulting from the relative standard deviation of the physiological concentrations of the identified metabolites had a mean of 18.20% (range between 9.3% and 44.8%). The reported concentrations for metabolites may be used as normal reference values. The homogeneity of the obtained results and the low biologic variability show that the 1H NMR analysis of the dog’s cerebrospinal fluid is reliable in designing and interpreting clinical and therapeutic trials in dogs with central nervous system pathologies. PMID:24376499

  7. Synthetic T1-weighted brain image generation with incorporated coil intensity correction using DESPOT1.

    PubMed

    Deoni, Sean C L; Rutt, Brian K; Peters, Terry M

    2006-11-01

    The increased use of phased-array and surface coils in magnetic resonance imaging, the push toward increased field strength and the need for standardized imaging across multiple sites during clinical trials have resulted in the need for methods that can ensure consistency of intensity both within the image and across multiple subjects/sites. Here, we describe a means of addressing these concerns through an extension of the rapid T(1) mapping technique - driven equilibrium single-pulse observation of T(1). The effectiveness of the proposed approach was evaluated using human brain T(1) maps acquired at 1.5 T with a multichannel phased-array coil. Corrected "synthetic" T(1)-weighted images were reconstructed by substituting the T(1) values back into the governing signal intensity equation while assuming a constant value for the equilibrium magnetization. To demonstrate signal normalization across a longitudinal study, we calculated synthetic T(1)-weighted images from data acquired from the same healthy subject at four different time points. Signal intensity profiles between the acquired and synthetic images were compared to determine the improvements with our proposed approach. Following correction, the images demonstrate obvious qualitative improvement with increased signal uniformity across the image. Near-perfect signal normalization was also observed across the longitudinal study, allowing direct comparison between the images. In addition, we observe an increase in contrast-to-noise ratio (compared with regular T(1)-weighted images) for synthetic images created, assuming uniform proton density throughout the volume. The proposed approach permits rapid correction for signal intensity inhomogeneity without significantly lengthening exam time or reducing image signal-to-noise ratio. This technique also provides a robust method for signal normalization, which is useful in multicenter longitudinal MR studies of disease progression, and allows the user to reconstruct T

  8. Hypothalamic involvement assessed by T1 relaxation time in patients with relapsing-remitting multiple sclerosis.

    PubMed

    Zellini, Francesco; Niepel, Graham; Tench, Christopher R; Constantinescu, Cris S

    2009-12-01

    Recent work in multiple sclerosis, focusing on neuropathological abnormalities, found a frequent and severe hypothalamic involvement. The possible clinical implications are disturbances in sleep and sexual activity, depression, memory impairment and fatigue. Despite this there are no magnetic resonance imaging studies focusing on in vivo hypothalamic pathology in multiple sclerosis. Our objective was to investigate magnetic resonance imaging-detectable abnormalities related to pathological changes in the hypothalamus of patients with multiple sclerosis, and to subsequently explore the relationship with fatigue. We used T1 relaxation time as a sensitive measure of pathology. Using region of interest analysis, median T1 values in the hypothalamus were measured in 44 relapsing-remitting multiple sclerosis patients and in 13 healthy controls. Fatigue was assessed using the Fatigue Severity Scale, and patients were divided in two subgroups, fatigued and non-fatigued, according to Fatigue Severity Scale scores. We found a significantly higher T1 relaxation time in the hypothalamus of multiple sclerosis patients compared with controls (p = 0.027). There was a significant correlation between T1 values and fatigue severity (rho 0.437, p = 0.008), and median T1 values were different among the study groups. Our results show that pathological involvement of the hypothalamus in relapsing-remitting multiple sclerosis is detectable using magnetic resonance imaging, and that the pathology measured by quantitative T1 might reflect fatigue. PMID:19995847

  9. Phase transition in triglycine sulfate crystals by 1H and 13C nuclear magnetic resonance in the rotating frame

    NASA Astrophysics Data System (ADS)

    Lim, Ae Ran; Jeong, Se-Young

    2013-09-01

    The ferroelectric phase transition in triglycine sulfate ((NH2CH2COOH)3·H2SO4, TGS)) crystals, occurring at TC of 322 K, was studied using 1H and 13C CP/MAS NMR. From the spin-lattice relaxation time in the rotating frame, T1ρ, of 1H and 13C, we found that the slopes of the T1ρ versus temperature curve changed near TC. In addition, the change of intensities for the protons and carbons NMR signals in the ferroelectric and the paraelectric phases led to the noticeable changes in the environments of proton and carbon in the carboxyl groups. The carboxyl ordering was the dominant factor driving the phase transition. Our study of the 1H and 13C spectra showed that the ferroelectric phase transition of TGS is of the order-disorder type due to ordering of the carboxyl groups.

  10. Comparison of T1 relaxation times of the neurochemical profile in rat brain at 9.4 tesla and 14.1 tesla.

    PubMed

    Cudalbu, Cristina; Mlynárik, Vladimír; Xin, Lijing; Gruetter, Rolf

    2009-10-01

    Knowledge of T(1) relaxation times can be important for accurate relative and absolute quantification of brain metabolites, for sensitivity optimizations, for characterizing molecular dynamics, and for studying changes induced by various pathological conditions. (1)H T(1) relaxation times of a series of brain metabolites, including J-coupled ones, were determined using a progressive saturation (PS) technique that was validated with an adiabatic inversion-recovery (IR) method. The (1)H T(1) relaxation times of 16 functional groups of the neurochemical profile were measured at 14.1T and 9.4T. Overall, the T(1) relaxation times found at 14.1T were, within the experimental error, identical to those at 9.4T. The T(1)s of some coupled spin resonances of the neurochemical profile were measured for the first time (e.g., those of gamma-aminobutyrate [GABA], aspartate [Asp], alanine [Ala], phosphoethanolamine [PE], glutathione [GSH], N-acetylaspartylglutamate [NAAG], and glutamine [Gln]). Our results suggest that T(1) does not increase substantially beyond 9.4T. Furthermore, the similarity of T(1) among the metabolites (approximately 1.5 s) suggests that T(1) relaxation time corrections for metabolite quantification are likely to be similar when using rapid pulsing conditions. We therefore conclude that the putative T(1) increase of metabolites has a minimal impact on sensitivity when increasing B(0) beyond 9.4T. PMID:19645007

  11. Water permeability of capillaries in the subfornical organ of rats determined by Gd-DTPA2- enhanced 1H magnetic resonance imaging

    PubMed Central

    Seo, Yoshiteru; Takamata, Akira; Ogino, Takashi; Morita, Hironobu; Nakamura, Shun; Murakami, Masataka

    2002-01-01

    The water permeability of capillaries in the subfornical organ (SFO) of rat was measured by a 1H nuclear magnetic resonance method in combination with a venous injection of a relaxation reagent, gadolinium-diethylene triamine-N,N,N′,N″,N″-pentaacetic acid (Gd-DTPA2-), which could not pass through the blood-brain barrier (BBB). Judging from results of Gd-DTPA2- dose dependency in the intact brain and the BBB-permeabilized brain, Gd-DTPA2- could not have leaked out from the capillaries in the cortex, thalamus or SFO, but it could have been extravasated in the posterior lobe of the pituitary gland. The longitudinal (T1) relaxation time of water in the SFO region was measured by inversion-recovery magnetic resonance imaging at 4.7 T. The T1 relaxation rates (1/T1) before and after Gd-DTPA2- infusion were 0.70 ± 0.02 s−1 (mean ± s.e.m., n = 9) and 1.53 ± 0.11 s−1 (n = 9), respectively. The rate constant for water influx to the capillaries was estimated to be 0.84 ± 0.11 s−1 (n = 9) which corresponds with a diffusive membrane permeability (Pd) of 3.7 × 10−3 cm s−1. Compared with values found in the literature available on this subject, this Pd value for the capillaries in the SFO was the same order of magnitude as that for transmembrane permeability of water for the vasa recta, and it may be 10–100 times larger than that of the blood-brain barrier in the cortex. Areas of the cortex and thalamus showed minimal changes in the T1 relaxation rate (ca 0.09 s−1), but these values were not statistically significant and they corresponded to Pd values much smaller than those found in the SFO. From these results, we conclude that the capillaries in the SFO have one of the highest water permeability values among all of the capillaries in the brain. It is also suggested that this magnetic resonance imaging, based on T1 relaxation rate, is a useful method to detect local water permeability in situ. PMID:12433962

  12. Observation of 1H-13C and 1H-1H proximities in a paramagnetic solid by NMR at high magnetic field under ultra-fast MAS.

    PubMed

    Li, Shenhui; Trébosc, Julien; Lafon, Olivier; Zhou, Lei; Shen, Ming; Pourpoint, Frédérique; Amoureux, Jean-Paul; Deng, Feng

    2015-02-01

    The assignment of NMR signals in paramagnetic solids is often challenging since: (i) the large paramagnetic shifts often mask the diamagnetic shifts specific to the local chemical environment, and (ii) the hyperfine interactions with unpaired electrons broaden the NMR spectra and decrease the coherence lifetime, thus reducing the efficiency of usual homo- and hetero-nuclear NMR correlation experiments. Here we show that the assignment of (1)H and (13)C signals in isotopically unmodified paramagnetic compounds with moderate hyperfine interactions can be facilitated by the use of two two-dimensional (2D) experiments: (i) (1)H-(13)C correlations with (1)H detection and (ii) (1)H-(1)H double-quantum↔single-quantum correlations. These methods are experimentally demonstrated on isotopically unmodified copper (II) complex of l-alanine at high magnetic field (18.8 T) and ultra-fast Magic Angle Spinning (MAS) frequency of 62.5 kHz. Compared to (13)C detection, we show that (1)H detection leads to a 3-fold enhancement in sensitivity for (1)H-(13)C 2D correlation experiments. By combining (1)H-(13)C and (1)H-(1)H 2D correlation experiments with the analysis of (13)C longitudinal relaxation times, we have been able to assign the (1)H and (13)C signals of each l-alanine ligand. PMID:25557861

  13. hPepT1 mediates bacterial tripeptide fMLP uptake in human monocytes.

    PubMed

    Charrier, Laetitia; Driss, Adel; Yan, Yutao; Nduati, Vivienne; Klapproth, Jan-Michael; Sitaraman, Shanthi V; Merlin, Didier

    2006-05-01

    Here, we examined hPepT1 expression in the monocytic cell line, KG-1. Reverse transcription polymerase chain reaction (RT-PCR) analysis revealed that hPepT1 is expressed in KG-1 cells, while cDNA cloning and direct sequencing confirmed the sequence of KG-1 hPepT1 (accession number, AY634368). Immunoblotting of cell lysates from KG-1 cells or macrophages isolated from human peripheral blood revealed a approximately 100 kDa immunoreactive band mainly present in the membrane fraction. Uptake experiments showed that the transport of 20 microM radiolabeled Gly-Sarcosine ([14C]Gly-Sar) in KG-1 cells was Na+, Cl- dependent and disodium 4,4'-diisothiocyanatostilbene-2,2'-disulfonate (DIDS)-sensitive. In addition, hPepT1 activity was likely to be coupled to a Na+/H+ exchanger, as evidenced by the fact that [14C]Gly-Sar uptake was not affected by the absence of Na+ when cells were incubated at low pH (5.2). Interestingly, hPepT1-mediated transport was reduced in KG-1 cells incubated at low pH as it was also observed in nonpolarized Caco2-BBE cells. This pattern of pH-dependence is due to a disruption of the driving force of hPepT1-mediated transport events. This was supported by our finding that nonpolarized cells, Caco2-BBE cells and KG-1 cells, have an increased permeability to H+ when compared to polarized Caco2-BBE cells. Finally, we showed that hPepT1 is responsible for transporting fMLP into undifferentiated and differentiated (macrophage-like) KG-1 cells. Together, these results show that hPepT1 is expressed in nonpolarized immune cells, such as macrophages, where the transporter functions best at the physiological pH 7.2. Furthermore, we provide evidence for hPepT1-mediated fMLP transport, which might constitute a novel immune cell activation pathway during intestinal inflammation. PMID:16568107

  14. L-Theanine elicits umami taste via the T1R1 + T1R3 umami taste receptor.

    PubMed

    Narukawa, Masataka; Toda, Yasuka; Nakagita, Tomoya; Hayashi, Yukako; Misaka, Takumi

    2014-06-01

    L-Theanine is a unique amino acid present in green tea. It elicits umami taste and has a considerable effect on tea taste and quality. We investigated L-theanine activity on the T1R1 + T1R3 umami taste receptor. L-Theanine activated T1R1 + T1R3-expressing cells and showed a synergistic response with inosine 5'-monophosphate. The site-directed mutagenesis analysis revealed that L-theanine binds to L-amino acid binding site in the Venus flytrap domain of T1R1. This study shows that L-theanine elicits an umami taste via T1R1 + T1R3. PMID:24633359

  15. Further exploration of MRI techniques for liver T1rho quantification.

    PubMed

    Zhao, Feng; Yuan, Jing; Deng, Min; Lu, Pu-Xuan; Ahuja, Anil T; Wang, Yi-Xiang J

    2013-12-01

    With biliary duct ligation and CCl4 induced rat liver fibrosis models, recent studies showed that MR T1rho imaging is able to detect liver fibrosis, and the degree of fibrosis is correlated with the degree of elevation of the T1rho measurements, suggesting liver T1rho quantification may play an important role for liver fibrosis early detection and grading. It has also been reported it is feasible to obtain consistent liver T1rho measurement for human subjects at 3 Tesla (3 T), and preliminary clinical data suggest liver T1rho is increased in patients with cirrhosis. In these previous studies, T1rho imaging was used with the rotary-echo spin-lock pulse for T1rho preparation, and number of signal averaging (NSA) was 2. Due to the presence of inhomogeneous B0 field, artifacts may occur in the acquired T1rho-weighted images. The method described by Dixon et al. (Magn Reson Med 1996;36:90-4), which is a hard RF pulse with 135° flip angle and same RF phase as the spin-locking RF pulse is inserted right before and after the spin-locking RF pulse, has been proposed to reduce sensitivity to B0 field inhomogeneity in T1rho imaging. In this study, we compared the images scanned by rotary-echo spin-lock pulse method (sequence 1) and the pulse modified according to Dixon method (sequence 2). When the artifacts occurred in T1rho images, we repeated the same scan until satisfactory. We accepted images if artifact in liver was less than 10% of liver area by visual estimation. When NSA =2, the breath-holding duration for data acquisition of one slice scanning was 8 sec due to a delay time of 6,000 ms for magnetization restoration. If NSA =1, the duration was shortened to be 2 sec. In previous studies, manual region of interest (ROI) analysis of T1rho map was used. In this current study, histogram analysis was also applied to evaluate liver T1rho value on T1rho maps. MRI data acquisition was performed on a 3 T clinical scanner. There were 29 subjects with 61 examinations obtained

  16. T1-201 chloride scintigraphy for bone tumors and soft part sarcomas

    SciTech Connect

    Terui, S.; Oyamada, H.; Nishikawa, K.; Beppu, Y.; Fukuma, H.

    1984-01-01

    The author investigated T1-201 chloride as a tumor scanning agent of both tumors and soft part sarcomas. Six bone tumors (2 with Ewing sarcoma, 3 with osteosarcoma and 1 with giant cell tumor) and 3 soft part sarcoma (1 with liposarcoma and 2 with malignant fibrous histiocytoma (MFH)) were examined. All but one MFH were untreated primary cases. The diagnosis was determined from biopsy specimen. One patient with Ewing sarcoma had bone metastases. All cases were subsequently received chemotherpeutic agents. Surgery or local irradiation were also used in treatment. T1-201 scintigraphy were performed with intravenous administration of 2 mCi of T1-201 chloride before initiation of therapy. In addition, follow-up examinations were done in 4 patients (2 with Ewing sarcoma and 2 with osteosarcoma) to study the effect of chemotherapy on T1-201 uptake by the tumor. Tc-99m bone scans were available for comparison in 6 tumor. Ga-67 citrate scans were also examined for the 3 soft part sarcomas. The untreated tumors even in the metastatic lesions of Ewing sarcoma were distinctly visualized with T1-201 in all cases. The distribution of T1-201 in the tumors was sometimes different from that of Tc-99m and similar to that of Ga-67. Of 3 out of the 4 follow-up patients, the post-therapy scan showed reduction in T1-201 uptake more markedly than Tc-99m uptake during effective chemotherapy. The other one patient had not responded to the treatment so that the scan showed no changes in T1-201 uptake. These findings indicate that the tumor imaging with T1-201 is useful in the diagnosis of these malignant tumors and may be of value in assessing the response of bone tumors to chemotherapy.

  17. T1 ρ MRI contrast in the human brain: Modulation of the longitudinal rotating frame relaxation shutter-speed during an adiabatic RF pulse

    NASA Astrophysics Data System (ADS)

    Michaeli, Shalom; Sorce, Dennis J.; Springer, Charles S.; Ugurbil, Kamil; Garwood, Michael

    2006-07-01

    Longitudinal relaxation in the rotating frame (T1ρ) is the dominant mechanism during a train of adiabatic full passage (AFP) RF pulses with no interpulse intervals, placed prior to an excitation pulse. Asymptotic apparent time constants (T1ρ ‧) were measured for human occipital lobe 1H2O at 4 T using brief imaging readouts following such pulse trains. Two members of the hyperbolic secant (HSn) AFP pulse family (n = 1 or 4; i.e., arising from different amplitude- and frequency-modulation functions) were used. These produced two different non-monoexponential signal decays during the pulse trains. Thus, there are differing contrasts in asymptotic T1ρ ‧ maps derived from these data. This behavior is quite different than that of 1H2O signals from an aqueous protein solution of roughly the same macromolecular volume fraction as tissue. The ROI-averaged decays from the two acquisitions can be simultaneously accommodated by a two-site-exchange model for an equilibrium isochronous process whose exchange condition is modulated during the pulse. The model employs a two-spin description of dipolar interaction fluctuations in each site. The intrinsic site R1ρ (≡T1ρ-1) value is sensitive to fluctuations at the effective Larmor frequency (ωeff) in the rotating frame, and this is modulated differently during the two types of AFP pulses. Agreement with the data is quite good for site orientation correlation time constants characteristic of macromolecule-interacting water (site A) and bulk-like water (site B). Since R1ρA is significantly modulated while R1ρB is not, the intrinsic relaxographic shutter-speed for the process (≡|R1ρA - R1ρB|), and thus the exchange condition, is modulated. However, the mean residence time (67 ms) and intrinsic population fraction (0.2) values found for site A are each rather larger than might be expected, suggesting a disproportionate role for the water molecules known to be "buried" within the large and concentrated macromolecules of

  18. Crystalline 1H-1,2,3-triazol-5-ylidenes

    DOEpatents

    Bertrand, Guy; Gulsado-Barrios, Gregorio; Bouffard, Jean; Donnadieu, Bruno

    2016-08-02

    The present invention provides novel and stable crystalline 1H-1,2,3 triazolium carbenes and metal complexes of 1H-1,2,3 triazolium carbenes. The present invention also provides methods of making 1H-1,2,3 triazolium carbenes and metal complexes of 1H-1,2,3 triazolium carbenes. The present invention also provides methods of using 1H-1,2,3 triazolium carbenes and metal complexes of 1H-1,2,3 triazolium carbenes in catalytic reactions.

  19. Rapid and simple determination of T1 relaxation times in time-domain NMR by Continuous Wave Free Precession sequence.

    PubMed

    Moraes, Tiago Bueno; Monaretto, Tatiana; Colnago, Luiz Alberto

    2016-09-01

    Longitudinal (T1) and transverse (T2) relaxation times have been widely used in time-domain NMR (TD-NMR) to determine several physicochemical properties of petroleum, polymers, and food products. The measurement of T2 through the CPMG pulse sequence has been used in most of these applications because it denotes a rapid, robust method. On the other hand, T1 has been occasionally used in TD-NMR due to the long measurement time required to collect multiple points along the T1 relaxation curve. Recently, several rapid methods to measure T1 have been proposed. Those methods based upon single shot, known as Continuous Wave Free Precession (CWFP) pulse sequences, have been employed in the simultaneous measurement of T1 and T2 in a rapid fashion. However, these sequences can be used exclusively in instrument featuring short dead time because the magnitude of the signal at thermal equilibrium is required. In this paper, we demonstrate that a special CWFP sequence with a low flip angle can be a simple and rapid method to measure T1 regardless of instruments dead time. Experimental results confirmed that the method called CWFP-T1 may be used to measure both single T1 value and T1 distribution in heterogeneous samples. Therefore, CWFP-T1 sequence can be a feasible alternative to CPMG in the determination of physicochemical properties, particularly in processes where fast protocols are requested such as industrial applications. PMID:27376553

  20. Rapid and simple determination of T1 relaxation times in time-domain NMR by Continuous Wave Free Precession sequence

    NASA Astrophysics Data System (ADS)

    Moraes, Tiago Bueno; Monaretto, Tatiana; Colnago, Luiz Alberto

    2016-09-01

    Longitudinal (T1) and transverse (T2) relaxation times have been widely used in time-domain NMR (TD-NMR) to determine several physicochemical properties of petroleum, polymers, and food products. The measurement of T2 through the CPMG pulse sequence has been used in most of these applications because it denotes a rapid, robust method. On the other hand, T1 has been occasionally used in TD-NMR due to the long measurement time required to collect multiple points along the T1 relaxation curve. Recently, several rapid methods to measure T1 have been proposed. Those methods based upon single shot, known as Continuous Wave Free Precession (CWFP) pulse sequences, have been employed in the simultaneous measurement of T1 and T2 in a rapid fashion. However, these sequences can be used exclusively in instrument featuring short dead time because the magnitude of the signal at thermal equilibrium is required. In this paper, we demonstrate that a special CWFP sequence with a low flip angle can be a simple and rapid method to measure T1 regardless of instruments dead time. Experimental results confirmed that the method called CWFP-T1 may be used to measure both single T1 value and T1 distribution in heterogeneous samples. Therefore, CWFP-T1 sequence can be a feasible alternative to CPMG in the determination of physicochemical properties, particularly in processes where fast protocols are requested such as industrial applications.

  1. Two Distinct Determinants of Ligand Specificity in T1R1/T1R3 (the Umami Taste Receptor)*

    PubMed Central

    Toda, Yasuka; Nakagita, Tomoya; Hayakawa, Takashi; Okada, Shinji; Narukawa, Masataka; Imai, Hiroo; Ishimaru, Yoshiro; Misaka, Takumi

    2013-01-01

    Umami taste perception in mammals is mediated by a heteromeric complex of two G-protein-coupled receptors, T1R1 and T1R3. T1R1/T1R3 exhibits species-dependent differences in ligand specificity; human T1R1/T1R3 specifically responds to l-Glu, whereas mouse T1R1/T1R3 responds more strongly to other l-amino acids than to l-Glu. The mechanism underlying this species difference remains unknown. In this study we analyzed chimeric human-mouse receptors and point mutants of T1R1/T1R3 and identified 12 key residues that modulate amino acid recognition in the human- and mouse-type responses in the extracellular Venus flytrap domain of T1R1. Molecular modeling revealed that the residues critical for human-type acidic amino acid recognition were located at the orthosteric ligand binding site. In contrast, all of the key residues for the mouse-type broad response were located at regions outside of both the orthosteric ligand binding site and the allosteric binding site for inosine-5′-monophosphate (IMP), a known natural umami taste enhancer. Site-directed mutagenesis demonstrated that the newly identified key residues for the mouse-type responses modulated receptor activity in a manner distinct from that of the allosteric modulation via IMP. Analyses of multiple point mutants suggested that the combination of two distinct determinants, amino acid selectivity at the orthosteric site and receptor activity modulation at the non-orthosteric sites, may mediate the ligand specificity of T1R1/T1R3. This hypothesis was supported by the results of studies using nonhuman primate T1R1 receptors. A complex molecular mechanism involving changes in the properties of both the orthosteric and non-orthosteric sites of T1R1 underlies the determination of ligand specificity in mammalian T1R1/T1R3. PMID:24214976

  2. T1-mapping in the heart: accuracy and precision

    PubMed Central

    2014-01-01

    The longitudinal relaxation time constant (T1) of the myocardium is altered in various disease states due to increased water content or other changes to the local molecular environment. Changes in both native T1 and T1 following administration of gadolinium (Gd) based contrast agents are considered important biomarkers and multiple methods have been suggested for quantifying myocardial T1 in vivo. Characterization of the native T1 of myocardial tissue may be used to detect and assess various cardiomyopathies while measurement of T1 with extracellular Gd based contrast agents provides additional information about the extracellular volume (ECV) fraction. The latter is particularly valuable for more diffuse diseases that are more challenging to detect using conventional late gadolinium enhancement (LGE). Both T1 and ECV measures have been shown to have important prognostic significance. T1-mapping has the potential to detect and quantify diffuse fibrosis at an early stage provided that the measurements have adequate reproducibility. Inversion recovery methods such as MOLLI have excellent precision and are highly reproducible when using tightly controlled protocols. The MOLLI method is widely available and is relatively mature. The accuracy of inversion recovery techniques is affected significantly by magnetization transfer (MT). Despite this, the estimate of apparent T1 using inversion recovery is a sensitive measure, which has been demonstrated to be a useful tool in characterizing tissue and discriminating disease. Saturation recovery methods have the potential to provide a more accurate measurement of T1 that is less sensitive to MT as well as other factors. Saturation recovery techniques are, however, noisier and somewhat more artifact prone and have not demonstrated the same level of reproducibility at this point in time. This review article focuses on the technical aspects of key T1-mapping methods and imaging protocols and describes their limitations including

  3. T1 Relaxation Time in Lungs of Asymptomatic Smokers

    PubMed Central

    Alamidi, Daniel F.; Kindvall, Simon S. I.; Hubbard Cristinacce, Penny L.; McGrath, Deirdre M.; Young, Simon S.; Naish, Josephine H.; Waterton, John C.; Wollmer, Per; Diaz, Sandra; Olsson, Marita; Hockings, Paul D.; Lagerstrand, Kerstin M.; Parker, Geoffrey J. M.; Olsson, Lars E.

    2016-01-01

    Purpose Interest in using T1 as a potential MRI biomarker of chronic obstructive pulmonary disease (COPD) has recently increased. Since tobacco smoking is the major risk factor for development of COPD, the aim for this study was to examine whether tobacco smoking, pack-years (PY), influenced T1 of the lung parenchyma in asymptomatic current smokers. Materials and Methods Lung T1 measurements from 35 subjects, 23 never smokers and 12 current smokers were retrospectively analyzed from an institutional review board approved study. All 35 subjects underwent pulmonary function test (PFT) measurements and lung T1, with similar T1 measurement protocols. A backward linear model of T1 as a function of FEV1, FVC, weight, height, age and PY was tested. Results A significant correlation between lung T1 and PY was found with a negative slope of -3.2 ms/year (95% confidence interval [CI] [-5.8, -0.6], p = 0.02), when adjusted for age and height. Lung T1 shortens with ageing among all subjects, -4.0 ms/year (95%CI [-6.3, -1.7], p = 0.001), and among the never smokers, -3.7 ms/year (95%CI [-6.0, -1.3], p = 0.003). Conclusions A correlation between lung T1 and PY when adjusted for both age and height was found, and T1 of the lung shortens with ageing. Accordingly, PY and age can be significant confounding factors when T1 is used as a biomarker in lung MRI studies that must be taken into account to detect underlying patterns of disease. PMID:26958856

  4. 1H-NMR study of the spin dynamics of fine superparamagnetic nanoparticles

    SciTech Connect

    Bordonali, L.; Furukawa, Y.; Kraken, M.; Litterst, F.J.; Sangregorio, C.; Casula, M.F.; Lascialfari, A.

    2012-05-25

    We report a broadband 1H-NMR study of the temperature spin dynamics of nearly monodisperse dextran-coated γ-Fe2O3 magnetic nanoparticles. We observed a maximum in T1−1(T) that decreases in amplitude and shifts toward higher temperatures with increasing field. We suggest that this is related to the progressive superparamagnetic spin blocking of the ferrite core. The data can be explained by assuming a single electronic spin-spin correlation time and introducing a field-dependent distribution of anisotropy energy barriers.

  5. Ultrashort TE T1ρ magic angle imaging.

    PubMed

    Du, Jiang; Statum, Sheronda; Znamirowski, Richard; Bydder, Graeme M; Chung, Christine B

    2013-03-01

    An ultrashort TE T(1)ρ sequence was used to measure T(1) ρ of the goat posterior cruciate ligament (n = 1) and human Achilles tendon specimens (n = 6) at a series of angles relative to the B(0) field and spin-lock field strengths to investigate the contribution of dipole-dipole interaction to T(1)ρ relaxation. Preliminary results showed a significant magic angle effect. T(1)ρ of the posterior cruciate ligament increased from 6.9 ± 1.3 ms at 0° to 36 ± 5 ms at 55° and then gradually reduced to 12 ± 3 ms at 90°. Mean T(1)ρ of the Achilles tendon increased from 5.5 ± 2.2 ms at 0° to 40 ± 5 ms at 55°. T(1)ρ dispersion study showed a significant T(1)ρ increase from 2.3 ± 0.9 ms to 11 ± 3 ms at 0° as the spin-lock field strength increased from 150 Hz to 1 kHz, and from 30 ± 3 ms to 42 ± 4 ms at 55° as the spin-lock field strength increased from 100 to 500 Hz. These results suggest that dipolar interaction is the dominant T(1)ρ relaxation mechanism in tendons and ligaments. PMID:22539354

  6. Voltage-dependent Gating Rearrangements in the Intracellular T1T1 Interface of a K+ Channel

    PubMed Central

    Wang, Guangyu; Covarrubias, Manuel

    2006-01-01

    The intracellular tetramerization domain (T1) of most eukaryotic voltage-gated potassium channels (Kv channels) exists as a “hanging gondola” below the transmembrane regions that directly control activation gating via the electromechanical coupling between the S4 voltage sensor and the main S6 gate. However, much less is known about the putative contribution of the T1 domain to Kv channel gating. This possibility is mechanistically intriguing because the T1–S1 linker connects the T1 domain to the voltage-sensing domain. Previously, we demonstrated that thiol-specific reagents inhibit Kv4.1 channels by reacting in a state-dependent manner with native Zn2+ site thiolate groups in the T1T1 interface; therefore, we concluded that the T1T1 interface is functionally active and not protected by Zn2+ (Wang, G., M. Shahidullah, C.A. Rocha, C. Strang, P.J. Pfaffinger, and M. Covarrubias. 2005. J. Gen. Physiol. 126:55–69). Here, we co-expressed Kv4.1 channels and auxiliary subunits (KChIP-1 and DPPX-S) to investigate the state and voltage dependence of the accessibility of MTSET to the three interfacial cysteines in the T1 domain. The results showed that the average MTSET modification rate constant (kMTSET) is dramatically enhanced in the activated state relative to the resting and inactivated states (∼260- and ∼47-fold, respectively). Crucially, under three separate conditions that produce distinct activation profiles, kMTSET is steeply voltage dependent in a manner that is precisely correlated with the peak conductance–voltage relations. These observations strongly suggest that Kv4 channel gating is tightly coupled to voltage-dependent accessibility changes of native T1 cysteines in the intersubunit Zn2+ site. Furthermore, cross-linking of cysteine pairs across the T1T1 interface induced substantial inhibition of the channel, which supports the functionally dynamic role of T1 in channel gating. Therefore, we conclude that the complex voltage

  7. A study of the aging of silicone breast implants using 29Si, 1H relaxation and DSC measurements.

    PubMed

    Birkefeld, Anja Britta; Eckert, Hellmut; Pfleiderer, Bettina

    2004-08-01

    In this study 26 previously implanted silicone breast implants from the same manufacturer (Dow Corning) were investigated with two different analytical methods to characterize potential aging processes such as migration of monomer material from the gel and shell to local and distant sites, chemical alterations of the polymer, and infiltration of body compounds such as lipids. (1)H and (29)Si NMR relaxation measurements (spin-lattice, T1, and spin-spin, T2, relaxation times) were used to study the molecular dynamics of polysiloxane chains, both in gels and in shells. In addition, changes in physical properties were monitored by differential scanning calorimetry (DSC). The results of these measurements indicate that NMR relaxation times are influenced by implant generation, implantation time, shell texture and implant status. (1)H T2 values of shells and gels show a tendency to increase with increasing implantation time, indicating higher mobility and possible disintegration of the polymer network of older implants. Furthermore, the data suggest that aging also involves the migration of low cyclic molecular weight (LMW) silicone and linear chain polymer material from the gels into the shells. The high "bleeding" rate of second-generation (G2) implants (implantation period around 1973-1985), exhibiting thin shells is reflected in reduced relaxation times of these devices, most likely due to a loss of low molecular weight fractions from the gels. Moreover, "gel bleeding" also influences the melting behavior observed in DSC studies. Increased shell rigidity (high Tm and Tg) tends to be correlated with longer (29)Si relaxation times of the corresponding gels, suggesting a reduced transfer of LMW silicones and linear chain polymer from the gel to the shell and to the outside. Remarkably, textured implants seem to be less susceptible to degradation processes than implants with thin shells. PMID:15046931

  8. T1ρ MRI detects cartilage damage in asymptomatic individuals with a cam deformity.

    PubMed

    Anwander, Helen; Melkus, Gerd; Rakhra, Kawan S; Beaulé, Paul E

    2016-06-01

    Hips with a cam deformity are at risk for early cartilage degeneration, mainly in the anterolateral region of the joint. T1ρ MRI is a described technique for assessment of proteoglycan content in hyaline cartilage and subsequently early cartilage damage. In this study, 1.5 Tesla T1ρ MRI was performed on 20 asymptomatic hips with a cam deformity and compared to 16 healthy control hips. Cam deformity was defined as an alpha angle at 1:30 o'clock position over 60° and/or at 3:00 o'clock position over 50.5°. Hip cartilage was segmented and divided into four regions of interest (ROIs): anterolateral, anteromedial, posterolateral, and posteromedial quadrants. Mean T1ρ value of the entire weight bearing cartilage in hips with a cam deformity (34.0 ± 4.6 ms) was significantly higher compared to control hips (31.3 ± 3.2 ms, p = 0.050). This difference reached significance in the anterolateral (p = 0.042) and posteromedial quadrants (p = 0.041). No significant correlation between the alpha angle and T1ρ values was detected. The results indicate cartilage damage occurs in hips with a cam deformity before symptoms occur. A significant difference in T1ρ values was found in the anterolateral quadrant, the area of direct engagement of the deformity, and in the posteromedial quadrant. To conclude, T1ρ MRI can detect early chondral damage in asymptomatic hips with a cam deformity. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1004-1009, 2016. PMID:26573964

  9. Bloch Equations-Based Reconstruction of Myocardium T1 Maps from Modified Look-Locker Inversion Recovery Sequence

    PubMed Central

    Marty, Benjamin; Vignaud, Alexandre; Greiser, Andreas; Robert, Benjamin; de Sousa, Paulo Loureiro; Carlier, Pierre G.

    2015-01-01

    Modified Look-Locker Inversion recovery (MOLLI) sequence is increasingly performed for myocardial T1 mapping but is known to underestimate T1 values. The aim of the study was to quantitatively analyze several sources of errors when T1 maps are derived using standard post-processing of the sequence and to propose a reconstruction approach that takes into account inversion efficacy (η), T2 relaxation during balanced steady-state free-precession readouts and B1+ inhomogeneities. Contributions of the different sources of error were analyzed using Bloch equations simulations of MOLLI sequence. Bloch simulations were then combined with the acquisition of fast B1+ and T2 maps to derive more accurate T1 maps. This novel approach was evaluated on phantoms and on five healthy volunteers. Simulations show that T2 variations, B1+ heterogeneities and inversion efficiency represent major confounders for T1 mapping when MOLLI is processed with standard 3-parameters fitting. In vitro data indicate that T1 values are accurately derived with the simulation approach and in vivo data suggest that myocardium T1 are 15% underestimated when processed with the standard 3-parameters fitting. At the cost of additional acquisitions, this method might be suitable in clinical research protocols for precise tissue characterization as it decorrelates T1 and T2 effects on parametric maps provided by MOLLI sequence and avoids inaccuracies when B1+ is not homogenous throughout the myocardium. PMID:25962182

  10. Genetic Variation in Myosin 1H Contributes to Mandibular Prognathism

    PubMed Central

    Tassopoulou-Fishell, Maria; Deeley, Kathleen; Harvey, Erika M.; Sciote, James; Vieira, Alexandre R.

    2013-01-01

    Introduction Several candidate loci have been suggested as influencing mandibular prognathism (1p22.1, 1p22.2, 1p36, 3q26.2, 5p13-p12, 6q25, 11q22.2-q22.3, 12q23, 12q13.13, and 19p13.2). The goal of this study was to replicate these results in a well-characterized homogeneous sample set. Methods Thirty-three single nucleotide polymorphisms spanning all candidate regions were studied in 44 prognathic and 35 Class I subjects from the University of Pittsburgh School of Dental Medicine Dental Registry and DNA Repository. The 44 mandibular prognathism subjects had an average age of 18.4 years, 31 were females and 13 males, and 24 were White, 15 African American, two Hispanic, and three Asian. The 35 Class I subjects had an average age of 17.6 years, 27 were females and 9 males, and 27 were White, six African Americans, one Hispanic, and two Asian. Skeletal mandibular prognathism diagnosis included cephalometric values indicative of Class III such as ANB smaller than two degrees, negative Witts appraisal, and positive A–B plane. Additional mandibular prognathism criteria included negative OJ and visually prognathic (concave) profile as determined by the subject's clinical evaluation. Orthognathic subjects without jaw deformations were used as a comparison group. Mandibular prognathism and orthognathic subjects were matched based on race, sex and age. Genetic markers were tested by polymerase chain reaction using TaqMan chemistry. Chi-square and Fisher exact tests were used to determine overrepresentation of marker allele with alpha of 0.05. Results An association was unveiled between a marker in MYO1H (rs10850110) and the mandibular prognathism phenotype (p=0.03). MYO1H is a Class-I myosin that is in a different protein group than the myosin isoforms of muscle sarcomeres, which are the basis of skeletal muscle fiber typing. Class I myosins are necessary for cell motility, phagocytosis and vesicle transport. Conclusions More strict clinical definitions may increase

  11. Measurement of Myocardial T1ρ with a Motion Corrected, Parametric Mapping Sequence in Humans

    PubMed Central

    Shahid, Mohammed; Han, Yuchi; Witschey, Walter R. T.

    2016-01-01

    Purpose To develop a robust T1ρ magnetic resonance imaging (MRI) sequence for assessment of myocardial disease in humans. Materials and Methods We developed a breath-held T1ρ mapping method using a single-shot, T1ρ-prepared balanced steady-state free-precession (bSSFP) sequence. The magnetization trajectory was simulated to identify sources of T1ρ error. To limit motion artifacts, an optical flow-based image registration method was used to align T1ρ images. The reproducibility and accuracy of these methods was assessed in phantoms and 10 healthy subjects. Results are shown in 1 patient with pre-ventricular contractions (PVCs), 1 patient with chronic myocardial infarction (MI) and 2 patients with hypertrophic cardiomyopathy (HCM). Results In phantoms, the mean bias was 1.0 ± 2.7 msec (100 msec phantom) and 0.9 ± 0.9 msec (60 msec phantom) at 60 bpm and 2.2 ± 3.2 msec (100 msec) and 1.4 ± 0.9 msec (60 msec) at 80 bpm. The coefficient of variation (COV) was 2.2 (100 msec) and 1.3 (60 msec) at 60 bpm and 2.6 (100 msec) and 1.4 (60 msec) at 80 bpm. Motion correction improved the alignment of T1ρ images in subjects, as determined by the increase in Dice Score Coefficient (DSC) from 0.76 to 0.88. T1ρ reproducibility was high (COV < 0.05, intra-class correlation coefficient (ICC) = 0.85–0.97). Mean myocardial T1ρ value in healthy subjects was 63.5 ± 4.6 msec. There was good correspondence between late-gadolinium enhanced (LGE) MRI and increased T1ρ relaxation times in patients. Conclusion Single-shot, motion corrected, spin echo, spin lock MRI permits 2D T1ρ mapping in a breath-hold with good accuracy and precision. PMID:27003184

  12. T1 mapping and survival in systemic light-chain amyloidosis

    PubMed Central

    Banypersad, Sanjay M.; Fontana, Marianna; Maestrini, Viviana; Sado, Daniel M.; Captur, Gabriella; Petrie, Aviva; Piechnik, Stefan K.; Whelan, Carol J.; Herrey, Anna S.; Gillmore, Julian D.; Lachmann, Helen J.; Wechalekar, Ashutosh D.; Hawkins, Philip N.; Moon, James C.

    2015-01-01

    Aims To assess the prognostic value of myocardial pre-contrast T1 and extracellular volume (ECV) in systemic amyloid light-chain (AL) amyloidosis using cardiovascular magnetic resonance (CMR) T1 mapping. Methods and results One hundred patients underwent CMR and T1 mapping pre- and post-contrast. Myocardial ECV was calculated at contrast equilibrium (ECVi) and 15 min post-bolus (ECVb). Fifty-four healthy volunteers served as controls. Patients were followed up for a median duration of 23 months and survival analyses were performed. Mean ECVi was raised in amyloid (0.44 ± 0.12) as was ECVb (mean 0.44 ± 0.12) compared with healthy volunteers (0.25 ± 0.02), P < 0.001. Native pre-contrast T1 was raised in amyloid (mean 1080 ± 87 ms vs. 954 ± 34 ms, P < 0.001). All three correlated with pre-test probability of cardiac involvement, cardiac biomarkers, and systolic and diastolic dysfunction. During follow-up, 25 deaths occurred. An ECVi of >0.45 carried a hazard ratio (HR) for death of 3.84 [95% confidence interval (CI): 1.53–9.61], P = 0.004 and pre-contrast T1 of >1044 ms = HR 5.39 (95% CI: 1.24–23.4), P = 0.02. Extracellular volume after primed infusion and ECVb performed similarly. Isolated post-contrast T1 was non-predictive. In Cox regression models, ECVi was independently predictive of mortality (HR = 4.41, 95% CI: 1.35–14.4) after adjusting for E:E′, ejection fraction, diastolic dysfunction grade, and NT-proBNP. Conclusion Myocardial ECV (bolus or infusion technique) and pre-contrast T1 are biomarkers for cardiac AL amyloid and they predict mortality in systemic amyloidosis. PMID:25411195

  13. Characterisation of the 1H and 13C NMR spectra of methylcitric acid

    NASA Astrophysics Data System (ADS)

    Krawczyk, Hanna; Martyniuk, Tomasz

    2007-06-01

    Methylcitric acid (MCA) was synthesised in Reformatsky reaction (2 RS, 3 RS stereoisomers) and in the nucleophilic addition (2 RS, 3 SR stereoisomers). The stereoselectivity of these reactions was analysed. 1H and 13C NMR spectra of diastereoisomers of methylcitric acid were recorded and interpreted. The values of 1H chemical shifts and 1H- 1H coupling constants were analysed. Proton-decoupled high-resolution 13C NMR spectra of MCA diastereoisomers were measured in a series of dilute water solutions of various acidities. These data may provide a basis for unequivocal determination of the presence of MCA in the urine samples of patients' suffering from propionic acidemia, methylmalonic aciduria, or holocarboxylase synthetase deficiency. NMR spectroscopy enables determination of MCA diastereoisomers in body fluids and can be a complementary and useful diagnostic tool.

  14. Molecular dynamics of tryptophan in ribonuclease-T1. I. Simulation strategies and fluorescence anisotropy decay.

    PubMed Central

    Axelsen, P H; Haydock, C; Prendergast, F G

    1988-01-01

    Molecular dynamics simulations of Ribonuclease-T1 (RNAse-T1) were performed using x-ray crystal coordinates for the enzyme and various simulation strategies. From each of the simulations, a predicted fluorescence anisotropy decay for the single-tryptophan residue was derived and compared with experimental values for the limiting anisotropy of this protein. Simulations conducted in vacuo demonstrated large displacements among some of the residues adjacent to the tryptophan side chain. As a consequence, the ring system rotates relatively unhindered through an angle far in excess of that implied by experimental data. In contrast, the explicit simulation of solvent within a stochastic boundary led to excellent agreement between simulation and experiment. In the case of RNAse-T1, the experimentally-determined limiting anisotropy is useful as a criterion of simulation accuracy in the vicinity of the tryptophan side chain. PMID:3145038

  15. Cerebral abnormalities: use of calculated T1 and T2 magnetic resonance images for diagnosis

    SciTech Connect

    Mills, C.M.; Crooks, L.E.; Kaufman, L.; Brant-Zawadzki, M.

    1984-01-01

    The potential clinical importance of T1 and T2 relaxation times in distinguishing normal and pathologic tissue with magnetic resonance (MR) is discussed and clinical examples of cerebral abnormalities are given. Five patients with cerebral infarction, 15 with multiple sclerosis, two with Wilson disease, and four with tumors were imaged. Hemorrhagic and ischemic cerebrovascular accidents were distinguished using the spin echo technique. In the patients with multiple sclerosis, lesions had prolonged T1 and T2 times, but the definition of plaque was limited by spatial resolution. No abnormalities in signal intensity were seen in the patient with Wilson disease who was no longer severly disabled; abnormal increased signal intensity in the basal ganglia was found in the second patient with Wilson disease. Four tumors produced abnormal T1 and T2 relaxation times but these values alone were not sufficient for tumor characterization.

  16. 7-T (1) H MRS with adiabatic refocusing at short TE using radiofrequency focusing with a dual-channel volume transmit coil.

    PubMed

    Boer, V O; van Lier, A L H M W; Hoogduin, J M; Wijnen, J P; Luijten, P R; Klomp, D W J

    2011-11-01

    In vivo MRS of the human brain at ultrahigh field allows for the identification of a large number of metabolites at higher spatial resolutions than currently possible in clinical practice. However, the in vivo localization of single-voxel spectroscopy has been shown to be challenging at ultrahigh field because of the low bandwidth of refocusing radiofrequency (RF) pulses. Thus far, the proposed methods for localized MRS at 7 T suffer from long TE, inherent signal loss and/or a large chemical shift displacement artifact that causes a spatial displacement between resonances, and results in a decreased efficiency in editing sequences. In this work, we show that, by driving a standard volume coil with two RF amplifiers, focusing the B 1+ field in a certain location and using high-bandwidth adiabatic refocusing pulses, a semi-LASER (semi-localized by adiabatic selective refocusing) localization is feasible at short TE in the human brain with full signal acquisition and a low chemical shift displacement artifact at 7 T. PMID:21294206

  17. A thermoalkaliphilic lipase of Geobacillus sp. T1.

    PubMed

    Leow, Thean Chor; Rahman, Raja Noor Zaliha Raja Abd; Basri, Mahiran; Salleh, Abu Bakar

    2007-05-01

    A thermoalkaliphilic T1 lipase gene of Geobacillus sp. strain T1 was overexpressed in pGEX vector in the prokaryotic system. Removal of the signal peptide improved protein solubility and promoted the binding of GST moiety to the glutathione-Sepharose column. High-yield purification of T1 lipase was achieved through two-step affinity chromatography with a final specific activity and yield of 958.2 U/mg and 51.5%, respectively. The molecular mass of T1 lipase was determined to be approximately 43 kDa by gel filtration chromatography. T1 lipase had an optimum temperature and pH of 70 degrees C and pH 9, respectively. It was stable up to 65 degrees C with a half-life of 5 h 15 min at pH 9. It was stable in the presence of 1 mM metal ions Na(+), Ca(2+), Mn(2+), K(+) and Mg(2+ ), but inhibited by Cu(2+), Fe(3+) and Zn(2+). Tween 80 significantly enhanced T1 lipase activity. T1 lipase was active towards medium to long chain triacylglycerols (C10-C14) and various natural oils with a marked preference for trilaurin (C12) (triacylglycerol) and sunflower oil (natural oil). Serine and aspartate residues were involved in catalysis, as its activity was strongly inhibited by 5 mM PMSF and 1 mM Pepstatin. The T(m) for T1 lipase was around 72.2 degrees C, as revealed by denatured protein analysis of CD spectra. PMID:17426920

  18. Characterization of Benign Myocarditis Using Quantitative Delayed-Enhancement Imaging Based on Molli T1 Mapping.

    PubMed

    Toussaint, Marcel; Gilles, Raymond J; Azzabou, Noura; Marty, Benjamin; Vignaud, Alexandre; Greiser, Andreas; Carlier, Pierre G

    2015-10-01

    Delayed contrast enhancement after injection of a gadolinium-chelate (Gd-chelate) is a reference imaging method to detect myocardial tissue changes. Its localization within the thickness of the myocardial wall allows differentiating various pathological processes such as myocardial infarction (MI), inflammatory myocarditis, and cardiomyopathies. The aim of the study was first to characterize benign myocarditis using quantitative delayed-enhancement imaging and then to investigate whether the measure of the extracellular volume fraction (ECV) can be used to discriminate between MI and myocarditis.In 6 patients with acute benign myocarditis (32.2 ± 13.8 year-old, subepicardial late gadolinium enhancement [LGE]) and 18 patients with MI (52.3 ± 10.9 year-old, subendocardial/transmural LGE), myocardial T1 was determined using the Modified Look-Locker Imaging (MOLLI) sequence at 3 Tesla before and after Gd-chelate injection. T1 values were compared in LGE and normal regions of the myocardium. The myocardial T1 values were normalized to the T1 of blood, and the ECV was calculated from T1 values of myocardium and blood pre- and post-Gd injection.In both myocarditis and MI, the T1 was lower in LGE regions than in normal regions of the left ventricle. T1 of LGE areas was significantly higher in myocarditis than in MI (446.8 ± 45.8 vs 360.5 ± 66.9 ms, P = 0.003) and ECV was lower in myocarditis than in MI (34.5 ± 3.3 vs 53.8 ± 13.0 %, P = 0.004).Both inflammatory process and chronic fibrosis induce LGE (subepicardial in myocarditis and subendocardial in MI). The present study demonstrates that the determination of T1 and ECV is able to differentiate the 2 histological patterns.Further investigation will indicate whether the severity of ECV changes might help refine the predictive risk of LGE in myocarditis. PMID:26512599

  19. Capturing fast relaxing spins with SWIFT adiabatic rotating frame spin-lattice relaxation (T1ρ ) mapping.

    PubMed

    Zhang, J; Nissi, M J; Idiyatullin, D; Michaeli, S; Garwood, M; Ellermann, J

    2016-04-01

    Rotating frame spin-lattice relaxation, with the characteristic time constant T1ρ , provides a means to access motion-restricted (slow) spin dynamics in MRI. As a result of their restricted motion, these spins are sometimes characterized by a short transverse relaxation time constant T2 and thus can be difficult to detect directly with conventional image acquisition techniques. Here, we introduce an approach for three-dimensional adiabatic T1ρ mapping based on a magnetization-prepared sweep imaging with Fourier transformation (MP-SWIFT) sequence, which captures signal from almost all water spin populations, including the extremely fast relaxing pool. A semi-analytical procedure for T1ρ mapping is described. Experiments on phantoms and musculoskeletal tissue specimens (tendon, articular and epiphyseal cartilages) were performed at 9.4 T for both the MP-SWIFT and fast spin echo (FSE) read outs. In the phantom with liquids having fast molecular tumbling and a single-valued T1ρ time constant, the measured T1ρ values obtained with MP-SWIFT and FSE were similar. Conversely, in normal musculoskeletal tissues, T1ρ values measured with MP-SWIFT were much shorter than the values obtained with FSE. Studies of biological tissue specimens demonstrated that T1ρ -weighted SWIFT provides higher contrast between normal and diseased tissues relative to conventional acquisitions. Adiabatic T1ρ mapping with SWIFT readout captures contributions from the otherwise undetected fast relaxing spins, allowing more informative T1ρ measurements of normal and diseased states. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26811973

  20. A novel method for simultaneous 3D B(1) and T(1) mapping: the method of slopes (MoS).

    PubMed

    Chavez, Sofia; Stanisz, Greg J

    2012-09-01

    A novel three-dimensional simultaneous B(1) and T(1) mapping method is introduced: the method of slopes (MoS). The linearity of the spoiled gradient recalled echo (SPGR) signal vs flip angle relation is exploited: B(1) mapping is achieved by a two-point extrapolation to signal null with a correction scheme while T(1) mapping uses the slopes of the SPGR signal vs flip angle curves near the origin and near the signal null. This new method improves upon the existing variable flip angle (VFA) T(1)-mapping method in that (i) consistency between B(1) and T(1) maps is ensured (ii) the sampling scheme is T(1)-independent (iii) the noise bias and singularity, associated with using a linear form for the SPGR signal equation, is eliminated by using the full equation. The method is shown to yield accurate and robust results via simulations. Initial estimates of B(1) and T(1) values are obtained from three data points via simple computations and straight line approximations. Initial estimates of B(1) values, for a range of values, are shown to be accurate due to the proposed B(1) correction scheme. The accuracy and robustness of T(1) values is achieved via a non-linear fitting algorithm which includes a fourth data point sampled at high SNR. The MoS was validated by comparing resulting B(1) and T(1) maps with those obtained using other standard methods. Finally, the ability to obtain brain B(1) and T(1) maps using the MoS was demonstrated by in vivo experiments. The MoS is expected to perform well on other motion-free anatomical regions as well. PMID:22368092

  1. Clinical Relevance of Single-Voxel 1H MRS Metabolites in Discriminating Suprasellar Tumors

    PubMed Central

    Virani, Rahul A

    2016-01-01

    Introdution Spatially resolved metabolic data obtained from Proton Magnetic Resonance Spectroscopy (1H MRS) provides information which increases the diagnostic accuracy of imaging sequences in predicting the histology of suprasellar tumors. Aim To evaluate the role of 1H MRS in the diagnosis of various suprasellar tumors. Materials and Methods Sixty cases of various suprasellar, hypothalamic and third ventricular neoplasms were investigated with long-echo single voxel 1H -MRS using 1.5 Tesla clinical imager. Single-voxel spectroscopic examinations were guided by T1-weighted or T2-weighted images. Statistical analysis was carried out using IBM SPSS software version 19. Results We observed that whenever brain tissue was damaged or replaced by any process, NAA was markedly reduced. Extra-axial lesions which do not infiltrate brain or contain neuroglial tissue, didn’t demonstrate any NAA resonances. Cr was used as an internal standard for semi-quantitative evaluation of metabolic changes of other brain metabolites. Increased Cho was seen in processes with elevated cell-membrane turnover. Conclusion Spectra obtained from different tumors exhibit reproducible differences while histologically similar tumors yield characteristic spectra with only minor differences. Pituitary tumors were typically characterized by significant reduction of NAA, Cr peak and moderate elevation of Cho peak. Gliomas were typically characterized by decrease of NAA and Cr peaks and increase of Cho peak. Craniopharyngiomas were typically characterized by significant decrease of all metabolites.

  2. State of the Art: Clinical Applications of Cardiac T1 Mapping.

    PubMed

    Schelbert, Erik B; Messroghli, Daniel R

    2016-03-01

    While cardiovascular magnetic resonance (MR) has become the noninvasive tool of choice for the assessment of myocardial viability and for the detection of acute myocardial edema, cardiac T1 mapping is believed to further extend the ability of cardiovascular MR to characterize the myocardium. Fundamentally, cardiovascular MR can improve diagnosis of disease that historically has been challenging to establish with other imaging modalities. For example, decreased native T1 values appear highly specific to detect and quantify disease severity related to myocardial iron overload states or glycosphingolipid accumulation in Anderson-Fabry disease, whereas high native T1 values are observed with edema, amyloid, and other conditions. Cardiovascular MR can also improve the assessment of prognosis with parameters that relate to myocardial structure and composition that complement the familiar functional parameters around which contemporary cardiology decision making revolves. In large cohorts, extracellular volume fraction (ECV) has been shown to quantify the full extent of myocardial fibrosis in noninfarcted myocardium. ECV may predict outcomes at least as effectively as left ventricular ejection fraction. This uncommon statistical observation (of potentially being more strongly associated with outcomes than ejection fraction) suggests prime biologic importance for the cardiac interstitium that may rank highly in the hierarchy of vast myocardial changes occurring in cardiac pathophysiology. This article presents current and developing clinical applications of cardiac T1 mapping and reviews the existing evidence on their diagnostic and prognostic value in various clinical conditions. This article also contextualizes these advances and explores how T1 mapping and ECV may affect major "global" issues such as diagnosis of disease, risk stratification, and paradigms of disease, and ultimately how we conceptualize patient vulnerability. PMID:26885733

  3. T1ρ MR Imaging of Human Musculoskeletal System

    PubMed Central

    Wang, Ligong; Regatte, Ravinder R.

    2014-01-01

    Magnetic resonance imaging (MRI) offers the direct visualization of human musculoskeletal (MSK) system, especially all diarthrodial tissues including cartilage, bone, menisci, ligaments, tendon, hip, synovium etc. Conventional MR imaging techniques based on T1- and T2-weighted, proton density (PD) contrast are inconclusive in quantifying early biochemically degenerative changes in MSK system in general and articular cartilage in particular. In recent years, quantitative MR parameter mapping techniques have been used to quantify the biochemical changes in articular cartilage with a special emphasis on evaluating joint injury, cartilage degeneration, and soft tissue repair. In this article, we will focus on cartilage biochemical composition, basic principles of T1ρ MR imaging, implementation of T1ρ pulse sequences, biochemical validation, and summarize the potential applications of T1ρ MR imaging technique in MSK diseases including osteoarthritis (OA), anterior cruciate ligament (ACL) injury, and knee joint repair. Finally, we will also review the potential advantages, challenges, and future prospects of T1ρ MR imaging for widespread clinical translation. PMID:24935818

  4. CHHC and 1H-1H Magnetization Exchange: Analysis by Experimental Solid-State NMR and 11-Spin Density-Matrix Simulations

    PubMed Central

    Aluas, Mihaela; Tripon, Carmen; Griffin, John M.; Filip, Xenia; Ladizhansky, Vladimir; Griffin, Robert G.; Brown, Steven P.; Filip, Claudiu

    2009-01-01

    A protocol is presented for correcting the effect of non-specific cross polarization in CHHC solid-state MAS NMR experiments, thus allowing the recovery of the 1H-1H magnetization exchange functions from the mixing-time dependent buildup of experimental CHHC peak intensity. The presented protocol also incorporates a scaling procedure to take into account the effect of multiplicity of a CH2 or CH3 moiety. Experimental CHHC buildup curves are presented for L-Tyrosine.HCl samples where either all or only one in ten molecules are U-13C labeled. Good agreement between experiment and 11-spin SPINEVOLUTION simulation (including only isotropic 1H chemical shifts) is demonstrated for the initial buildup (tmix < 100 μs) of CHHC peak intensity corresponding to an intramolecular close (2.5 Å) H-H proximity. Differences in the initial CHHC buildup are observed between the 1 in 10 dilute and 100 % samples for cases where there is a close intermolecular H-H proximity in addition to a close intramolecular H-H proximity. For the dilute sample, CHHC cross peak intensities tended to significantly lower values for long mixing times (500 μs) as compared to the 100 % sample. This difference is explained as being due to the dependence of the limiting total magnetization on the ratio Nobs/Ntot between the number of protons that are directly attached to a 13C nucleus and hence contribute significantly to the observed 13C CHHC NMR signal, and the total number of 1H spins into the system. 1H-1H magnetization exchange curves extracted from CHHC spectra for the 100 % L-Tyrosine.HCl sample exhibit a clear sensitivity to the root sum squared dipolar coupling, with fast build-up being observed for the shortest intramolecular distances (2.5 Å) and slower, yet observable build-up for the longer intermolecular distances (up to 5 Å). PMID:19467890

  5. Whole brain myelin mapping using T1- and T2-weighted MR imaging data

    PubMed Central

    Ganzetti, Marco; Wenderoth, Nicole; Mantini, Dante

    2014-01-01

    Despite recent advancements in MR imaging, non-invasive mapping of myelin in the brain still remains an open issue. Here we attempted to provide a potential solution. Specifically, we developed a processing workflow based on T1-w and T2-w MR data to generate an optimized myelin enhanced contrast image. The workflow allows whole brain mapping using the T1-w/T2-w technique, which was originally introduced as a non-invasive method for assessing cortical myelin content. The hallmark of our approach is a retrospective calibration algorithm, applied to bias-corrected T1-w and T2-w images, that relies on image intensities outside the brain. This permits standardizing the intensity histogram of the ratio image, thereby allowing for across-subject statistical analyses. Quantitative comparisons of image histograms within and across different datasets confirmed the effectiveness of our normalization procedure. Not only did the calibrated T1-w/T2-w images exhibit a comparable intensity range, but also the shape of the intensity histograms was largely corresponding. We also assessed the reliability and specificity of the ratio image compared to other MR-based techniques, such as magnetization transfer ratio (MTR), fractional anisotropy (FA), and fluid-attenuated inversion recovery (FLAIR). With respect to these other techniques, T1-w/T2-w had consistently high values, as well as low inter-subject variability, in brain structures where myelin is most abundant. Overall, our results suggested that the T1-w/T2-w technique may be a valid tool supporting the non-invasive mapping of myelin in the brain. Therefore, it might find important applications in the study of brain development, aging and disease. PMID:25228871

  6. The Conformations and Structures of 1H-NONAFLUOROBUTANE

    NASA Astrophysics Data System (ADS)

    Fournier, Joseph A.; Bohn, Robert K.; Montgomery, John A.; , Jr.

    2012-06-01

    The all trans conformers of perfluorocarbons, unlike hydrocarbons, are helical with C-C-C-C dihedral angles about 1640. Fluorocarbons with H substitution can replace chlorofluorocarbons as propellants and compressor fluids without the disadvantage of causing ozone depletion in the upper atmosphere. 1H-perfluorobutane, CHF_2CF_2CF_2CF_3, has been studied by pulsed-jet Fourier transform microwave spectroscopy. The spectrum is very rich. Quantum chemical calculations identify five stable conformers with relative energies up to 1.1 kcal/mol. Thus far three conformers have been characterized and many lines remain unassigned. The assigned species have CCCCanti/CCCH gauche as well as the anti/anti and gauche/anti forms. Rotational constant values are 1428.9501(2) MHz, 593.323877(6) MHz, and 546.43578(6) MHz for the anti/gauche species, 1323.664(3) MHz, 617.6051(5) MHz for the ant/anti species, and 1066.9384(4) MHz, 768.4736(4) MHz, and 671.3145(4) MHz for the gauche/anti form.

  7. Estimating T1 from multichannel variable flip angle SPGR sequences.

    PubMed

    Trzasko, Joshua D; Mostardi, Petrice M; Riederer, Stephen J; Manduca, Armando

    2013-06-01

    Quantitative estimation of T1 is a challenging but important task inherent to many clinical applications. The most commonly used paradigm for estimating T1 in vivo involves performing a sequence of spoiled gradient-recalled echo acquisitions at different flip angles, followed by fitting of an exponential model to the data. Although there has been substantial work comparing different fitting methods, there has been little discussion on how these methods should be applied for data acquired using multichannel receivers. In this note, we demonstrate that the manner in which multichannel data is handled can have a substantial impact on T1 estimation performance and should be considered equally as important as choice of flip angles or fitting strategy. PMID:22807160

  8. Estimating T1 from Multichannel Variable Flip Angle SPGR Sequences

    PubMed Central

    Trzasko, Joshua D.; Mostardi, Petrice M.; Riederer, Stephen J.; Manduca, Armando

    2013-01-01

    Quantitative estimation of T1 is a challenging but important task inherent to many clinical applications. The most commonly used paradigm for estimating T1 in vivo involves performing a sequence of spoiled gradient-recalled echo acquisitions at different flip angles, followed by fitting of an exponential model to the data. Although there has been substantial work comparing different fitting methods, there has been little discussion on how these methods should be applied for data acquired using multichannel receivers. In this note, we demonstrate that the manner in which multichannel data is handled can have a substantial impact on T1 estimation performance and should be considered equally as important as choice of flip angles or fitting strategy. PMID:22807160

  9. Can Native T1 Mapping Differentiate between Healthy and Diffuse Diseased Myocardium in Clinical Routine Cardiac MR Imaging?

    PubMed Central

    Goebel, Juliane; Seifert, Ingmar; Nensa, Felix; Schemuth, Haemi P.; Maderwald, Stefan; Quick, Harald H.; Schlosser, Thomas; Jensen, Christoph; Bruder, Oliver; Nassenstein, Kai

    2016-01-01

    Objectives T1 mapping allows quantitative myocardial assessment, but its value in clinical routine remains unclear. We investigated, whether the average native myocardial T1 value can be used as a diagnostic classifier between healthy and diffuse diseased myocardium. Methods Native T1 mapping was performed in 54 persons with healthy hearts and in 150 patients with diffuse myocardial pathologies (coronary artery disease (CAD): n = 76, acute myocarditis: n = 19, convalescent myocarditis: n = 26, hypertrophic cardiomyopathy (HCM): n = 12, dilated cardiomyopathy (DCM): n = 17) at 1.5 Tesla in a mid-ventricular short axis slice using a modified Look-Locker inversion recovery (MOLLI) sequence. The average native myocardial T1 value was measured using dedicated software for each patient. The mean as well as the range of the observed average T1 values were calculated for each group, and compared using t-test. The ability of T1 mapping to differentiate between healthy and diffuse diseased myocardium was assessed using receiver operating characteristic analysis (ROC). Results The mean T1 value of the group “healthy hearts” (955±34ms) differed significantly from that of the groups DCM (992±37ms, p<0.001), HCM (980±44ms, p = 0.035), and acute myocarditis (974±36ms, p = 0.044). No significant difference was observed between the groups “healthy hearts” and CAD (951±37ms, p = 0.453) or convalescent myocarditis (965±40ms, p = 0.240). The average native T1 value varied considerably within all groups (range: healthy hearts, 838-1018ms; DCM, 882-1034ms; HCM, 897-1043ms; acute myocarditis, 925-1025ms; CAD, 867-1082ms; convalescent myocarditis, 890-1071ms) and overlapped broadly between all groups. ROC analysis showed, that the average native T1 value does not allow for differentiating between healthy and diffuse diseased myocardium, except for the subgroup of DCM. Conclusions The average native T1 value in cardiac MR imaging does not allow differentiating between healthy

  10. Paramagnetic NMR relaxation in polymeric matrixes: sensitivity enhancement and selective suppression of embedded species (1H and 13C PSR filter).

    PubMed

    Fernandez-Megia, Eduardo; Correa, Juan; Novoa-Carballal, Ramon; Riguera, Ricardo

    2007-12-12

    A study of the practical applications of the addition of paramagnetic spin relaxation (PSR) ions to a variety of polymers (PLL, PAA, PGA, PVP, and polysaccharides such as hyaluronic acid, chitosan, mannan, and dextran) in solution (D2O and DMSO-d6) is described. Use of Gd(III), Cu(II), and Mn(II) allows a reduction of up to 500% in the 1H longitudinal relaxation times (T1), and so in the time necessary for recording quantitative NMR spectra (sensitivity enhancement) neither an increase of the spectral line width nor chemical shift changes resulted from addition of any of the PSR agents tested. Selective suppression of the 1H and 13C NMR signals of certain components (low MW molecules and polymers) in the spectrum of a mixture was attained thanks to their different sensitivity [transverse relaxation times (T2)] to Gd(III) (PSR filter). Illustration of this strategy with block copolymers (PGA-g-PEG) and mixtures of polymers and low MW molecules (i.e., lactose-hyaluronic acid, dextran-PAA, PVP-glutamic acid) in 1D and 2D NMR experiments (COSY and HMQC) is presented. In those mixtures where PSR and CPMG filters alone failed in the suppression of certain components (i.e., PVP-mannan-hyaluronic acid) due to their similarity of 1H T2 values and sensitivities to Gd(III), use of the PSR filter in combination with CPMG sequences (PSR-CPMG filter) successfully resulted in the sequential suppression of the components (hyaluronic acid first and then mannan). PMID:18004845

  11. Management of colorectal T1 carcinoma treated by endoscopic resection.

    PubMed

    Saitoh, Yusuke; Inaba, Yuhei; Sasaki, Takahiro; Sugiyama, Ryuji; Sukegawa, Ryuji; Fujiya, Mikihiro

    2016-04-01

    As a result of recent advances in endoscopic therapeutic technology, the number of endoscopic resections carried out in the treatment of early colorectal carcinomas with little risk of lymph node metastasis has increased. There are no reports of lymph node metastasis in intramucosal (Tis) carcinomas, whereas lymph node metastasis occurs in 6.8-17.8% of submucosal (T1) carcinomas. Three clinical guidelines have been published in Japan and the management strategy for early colorectal tumors has been demonstrated. According to the 2014 Japanese Society for Cancer of the Colon and Rectum (JSCCR) Guidelines for the Treatment of Colorectal Cancer, additional surgery should be done in cases of endoscopically resected T1 carcinoma with a histologically diagnosed positive vertical margin. Additional surgery may also be considered when one of the following histological findings is detected: (i) SM invasion depth ≥1000 µm; (ii) histological type por., sig., or muc.; (iii) grade 2-3 tumor budding; and (iv) positive vascular permeation. A resected lesion that is histologically diagnosed as a T1 carcinoma without any of the above-mentioned findings can be followed up without additional surgery. As for the prognosis of endoscopically resected T1 carcinomas, the relapse ratio of approximately 3.4% (44/1312) is relatively low. However, relapse is associated with a poor prognosis, with 72 cancer-related deaths reported out of 134 relapsed cases (54%). A more detailed stratification of the lymph node metastasis risk after endoscopic resection for T1 carcinomas and the prognosis of relapsed cases will be elucidated through prospective studies. Thereafter, the appropriate indications and safe and secure endoscopic resection for T1 carcinomas will be established. PMID:26076802

  12. A novel enterocin T1 with anti-Pseudomonas activity produced by Enterococcus faecium T1 from Chinese Tibet cheese.

    PubMed

    Liu, Hui; Zhang, Lanwei; Yi, Huaxi; Han, Xue; Gao, Wei; Chi, Chunliang; Song, Wei; Li, Haiying; Liu, Chunguang

    2016-02-01

    An enterocin-producing Enterococcus faecium T1 was isolated from Chinese Tibet cheese. The enterocin was purified by SP-Sepharose and reversed phase HPLC. It was identified as unique from other reported bacteriocins based on molecular weight (4629 Da) and amino acid compositions; therefore it was subsequently named enterocin T1. Enterocin T1 was stable at 80-100 °C and over a wide pH range, pH 3.0-10.0. Protease sensitivity was observed to trypsin, pepsin, papain, proteinase K, and pronase E. Importantly, enterocin T1 was observed to inhibit the growth of numerous Gram-negative and Gram-positive bacteria including Pseudomonas putida, Pseudomonas aeruginosa, Pseudomonas fluorescens, Escherichia coli, Salmonella typhimurium, Shigella flexneri, Shigella sonnei, Staphylococcus aureus, Listeria monocytogenes. Take together, these results suggest that enterocin T1 is a novel bacteriocin with the potential to be used as a bio-preservative to control Pseudomonas spp. in food. PMID:26745981

  13. T2 can be greater than 2T1

    NASA Astrophysics Data System (ADS)

    Sevian, H. M.; Skinner, J. L.

    1989-08-01

    We consider a quantum-mechanical two-level system under the influence of both diagonal and off-diagonal stochastic perturbations, and focus on the decay times T1 and T2, which refer to the relaxation to equilibrium of the populations and relative phase of the two levels, respectively. From both theoretical and experimental viewpoints one traditionally expects that T2≤2T1. On the other hand, from a fourth-order cumulant expansion calculation of the asymptotic time dependence of the density matrix elements, Budimir and Skinner [J. Stat. Phys. 49, 1029 (1987)] showed that, in fact, in some instances T2>2T1. In this paper we solve the stochastic model numerically, which leads to the exact time dependence of the density matrix at all times. We find that the analytic prediction that T2>2T1 is not only correct, but also meaningful, in the sense that the density matrix elements decay exponentially after only a short transient time.

  14. Cross Polarization for 1H NMR Image Contrast in Solids

    NASA Astrophysics Data System (ADS)

    Nakai, Toshihito; Fukunaga, Yasuhiro; Nonaka, Masayuki; Matsui, Shigeru; Inouye, Tamon

    1998-09-01

    A novel1H imaging method for solids, yielding images reflecting1H-13C dipolar interactions through cross relaxation timeTIS, is presented. Phase-alternating multiple-contact cross polarization (PAMC CP) was incorporated into the magic-echo frequency-encoding imaging scheme; the PAMC CP sequence may partly but efficiently destroy the initial1H magnetization depending on theTISvalues. A theory describing the effects of the PAMC CP sequence was developed, which was used for the assessment of the sequence as well as the analysis for the experimental results. It was demonstrated that theTIS-weighted1H image and theTISmapping for a phantom, constituted of adamantane and ferrocene, can distinguish these compounds clearly.

  15. Binding of Sulfonamide Antibiotics to CTABr Micelles Characterized Using (1)H NMR Spectroscopy.

    PubMed

    Sarker, Ashish K; Cashin, Patrick J; Balakrishnan, Vimal K; Exall, Kirsten; Buncel, Erwin; Brown, R Stephen

    2016-08-01

    Interactions of nine sulfonamide antibiotics (sulfadoxine, sulfathiazole, sulfamethoxazole, sulfamerazine, sulfadiazine, sulfamethazine, sulfacetamide, sulfaguanidine, and sulfanilamide) with cetyltrimethylamonium bromide (CTABr) micelles were examined using (1)H NMR spectroscopy. Seven of the nine provided a significant change in the (1)H NMR chemical shift such that the magnitude and direction (upfield vs downfield) of the chemical shift could be used to propose a locus and orientation of the sulfonamide within the micelle structure. The magnitude of the chemical shift was used to estimate the binding constant for seven sulfonamides with CTABr micelles, providing values and an overall pattern consistent with previous studies of these sulfonamides. PMID:27391918

  16. Upregulation of the long noncoding RNA HOTAIR predicts recurrence in stage Ta/T1 bladder cancer.

    PubMed

    Yan, Ting-Hua; Lu, Sui-Wan; Huang, Yong-Qing; Que, Gan-Bo; Chen, Jun-Hui; Chen, Yong-Ping; Zhang, Hong-Bin; Liang, Xing-Lan; Jiang, Jin-Hua

    2014-10-01

    Stage Ta/T1 urothelial carcinoma of the bladder (Ta/T1 BC) has a marked tendency to recurrence. Long noncoding RNA HOTAIR has been reported to be expressed in some human cancers such as breast cancer, and it may be positively correlated with patient's prognosis. The aim of our study was to evaluate the prognostic value of HOTAIR in Ta/T1 BC. HOTAIR expression in Ta/T1 BC tissues and adjacent normal tissues was collected from 110 patients and measured by real-time quantitative PCR. The relationships between HOTAIR and the clinical pathological characteristics of Ta/T1 BC patients were analyzed. Immunohistochemistry was done to detect the protein of Wnt inhibitory factor 1 (WIF-1) as well. Ninety out of 110 specimens were detected in HOTAIR high expression. Histological grade and expression levels of HOTAIR were positively correlated with the recurrence rate. HOTAIR expression (hazard ratio 4.712; 95 % CI 2.894-8.714; P < 0.001) was an independent predictor of recurrence rate in multivariate Cox regression analysis. HOTAIR expression is correlated with patients' poor prognosis. A significant inverse correlation between HOTAIR and WIF-1 expression was demonstrated in Ta/T1 BC tissues. The expression levels of HOTAIR are an independent prognostic factor of recurrence in Ta/T1 BC patients. PMID:25030736

  17. Predictability of 1-h postload plasma glucose concentration: A 10-year retrospective cohort study

    PubMed Central

    Kuang, Lifen; Huang, Zhimin; Hong, Zhenzhen; Chen, Ailing; Li, Yanbing

    2015-01-01

    Aims/Introduction Elevated 1-h postload plasma glucose concentration (1hPG) during oral glucose tolerance test has been linked to an increased risk of type 2 diabetes and a poorer cardiometabolic risk profile. The present study analyzed the predictability and cut-off point of 1hPG in predicting type 2 diabetes in normal glucose regulation (NGR) subjects, and evaluated the long-term prognosis of NGR subjects with elevated 1hPG in glucose metabolism, kidney function, metabolic states and atherosclerosis. Materials and Methods A total of 116 Han Chinese classified as NGR in 2002 at the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China, were investigated. Follow-up was carried out in 2012 to evaluate the progression of glucose metabolism, kidney function, metabolic syndrome and carotid atherosclerosis. Results The areas under receiver operating characteristic curves were higher for 1hPG than FPG or 2hPG (0.858 vs 0.806 vs 0.746). The cut-off value of 1hPG with the maximal sum of sensitivity and specificity in predicting type 2 diabetes in NGR subjects was 8.85 mmol/L. The accumulative incidence of type 2 diabetes in subjects with 1hPG ≥8.85 mmol/L was higher than those <8.85 mmol/L (46.2% vs 3.3%, P = 0.000; relative risk 13.846, 95% confidence interval 4.223–45.400). On follow up, the prevalence of metabolic syndrome and abnormal carotid intima-media thickness in the subjects with 1hPG ≥8.85 mmol/L tended to be higher compared with those <8.85 mmol/L. Conclusions 1hPG is a good predictor of type 2 diabetes in NGR subjects, and the best cut-off point is 8.85 mmol/L. Some tendency indicates that NGR subjects with 1hPG ≥8.85 mmol/L are more prone to metabolic syndrome and carotid atherosclerosis. PMID:26543538

  18. Metabolomic differentiation of Cannabis sativa cultivars using 1H NMR spectroscopy and principal component analysis.

    PubMed

    Choi, Young Hae; Kim, Hye Kyong; Hazekamp, Arno; Erkelens, Cornelis; Lefeber, Alfons W M; Verpoorte, Robert

    2004-06-01

    The metabolomic analysis of 12 Cannabis sativa cultivars was carried out by 1H NMR spectroscopy and multivariate analysis techniques. Principal component analysis (PCA) of the 1H NMR spectra showed a clear discrimination between those samples by principal component 1 (PC1) and principal component 3 (PC3) in cannabinoid fraction. The loading plot of PC value obtained from all 1)H NMR signals shows that Delta9-tetrahydrocannabinolic acid (THCA) and cannabidiolic acid (CBDA) are important metabolites to differentiate the cultivars from each other. The discrimination of the cultivars could also be obtained from a water extract containing carbohydrates and amino acids. The level of sucrose, glucose, asparagine, and glutamic acid are found to be major discriminating metabolites of these cultivars. This method allows an efficient differentiation between cannabis cultivars without any prepurification steps. PMID:15217272

  19. Rapid solid-state NMR of deuterated proteins by interleaved cross-polarization from 1H and 2H nuclei

    NASA Astrophysics Data System (ADS)

    Bjerring, Morten; Paaske, Berit; Oschkinat, Hartmut; Akbey, Ümit; Nielsen, Niels Chr.

    2012-01-01

    We present a novel sampling strategy, interleaving acquisition of multiple NMR spectra by exploiting initial polarization subsequently from 1H and 2H spins, taking advantage of their different T1 relaxation times. Different 1H- and 2H-polarization based spectra are in this way simultaneously recorded improving either information content or sensitivity by adding spectra. The so-called Relaxation-optimized Acquisition of Proton Interleaved with Deuterium (RAPID) 1H → 13C/ 2H → 13C CP/MAS multiple-acquisition method is demonstrated by 1D and 2D experiments using a uniformly 2H, 15N, 13C-labeled α-spectrin SH3 domain sample with all or 30% back-exchanged labile 2H to 1H. It is demonstrated how 1D 13C CP/MAS or 2D 13C- 13C correlation spectra initialized with polarization from either 1H or 2H may be recorded simultaneously with flexibility to be added or used individually for spectral editing. It is also shown how 2D 13C- 13C correlation spectra may be recorded interleaved with 2H- 13C correlation spectra to obtain 13C- 13C correlations along with information about dynamics from 2H sideband patterns.

  20. Cardiovascular magnetic resonance by non contrast T1-mapping allows assessment of severity of injury in acute myocardial infarction

    PubMed Central

    2012-01-01

    Background Current cardiovascular magnetic resonance (CMR) methods, such as late gadolinium enhancement (LGE) and oedema imaging (T2W) used to depict myocardial ischemia, have limitations. Novel quantitative T1-mapping techniques have the potential to further characterize the components of ischemic injury. In patients with myocardial infarction (MI) we sought to investigate whether state-of the art pre-contrast T1-mapping (1) detects acute myocardial injury, (2) allows for quantification of the severity of damage when compared to standard techniques such as LGE and T2W, and (3) has the ability to predict long term functional recovery. Methods 3T CMR including T2W, T1-mapping and LGE was performed in 41 patients [of these, 78% were ST elevation MI (STEMI)] with acute MI at 12-48 hour after chest pain onset and at 6 months (6M). Patients with STEMI underwent primary PCI prior to CMR. Assessment of acute regional wall motion abnormalities, acute segmental damaged fraction by T2W and LGE and mean segmental T1 values was performed on matching short axis slices. LGE and improvement in regional wall motion at 6M were also obtained. Results We found that the variability of T1 measurements was significantly lower compared to T2W and that, while the diagnostic performance of acute T1-mapping for detecting myocardial injury was at least as good as that of T2W-CMR in STEMI patients, it was superior to T2W imaging in NSTEMI. There was a significant relationship between the segmental damaged fraction assessed by either by LGE or T2W, and mean segmental T1 values (P < 0.01). The index of salvaged myocardium derived by acute T1-mapping and 6M LGE was not different to the one derived from T2W (P = 0.88). Furthermore, the likelihood of improvement of segmental function at 6M decreased progressively as acute T1 values increased (P < 0.0004). Conclusions In acute MI, pre-contrast T1-mapping allows assessment of the extent of myocardial damage. T1-mapping might become an important

  1. Breath-hold black blood quantitative T1rho imaging of liver using single shot fast spin echo acquisition

    PubMed Central

    Chan, Queenie; Wáng, Yì-Xiáng J.

    2016-01-01

    Background Liver fibrosis is a key feature in most chronic liver diseases. T1rho magnetic resonance imaging is a potentially important technique for noninvasive diagnosis, severity grading, and therapy monitoring of liver fibrosis. However, it remains challenging to perform robust T1rho quantification of liver on human subjects. One major reason is that the presence of rich blood signal in liver can cause artificially high T1rho measurement and makes T1rho quantification susceptible to motion. Methods A pulse sequence based on single shot fast/turbo spin echo (SSFSE/SSTSE) acquisition, with theoretical analysis and simulation based on the extended phase graph (EPG) algorithm, was presented for breath-hold single slice quantitative T1rho imaging of liver with suppression of blood signal. The pulse sequence was evaluated in human subjects at 3.0 T with 500 Hz spinlock frequency and time-of-spinlock (TSL) 0, 10, 30 and 50 ms. Results Human scan demonstrated that the entire T1rho data sets with four spinlock time can be acquired within a single breath-hold of 10 seconds with black blood effect. T1rho quantification with suppression of blood signal results in significantly reduced T1rho value of liver compared to the results without blood suppression. Conclusions A signal-to-noise ratio (SNR) efficient pulse sequence was reported for T1rho quantification of liver. The black blood effect, together with a short breath-hold, mitigates the risk of quantification errors as would occur in the conventional methods. PMID:27190769

  2. Functionally Active T1-T1 Interfaces Revealed by the Accessibility of Intracellular Thiolate Groups in Kv4 Channels

    PubMed Central

    Wang, Guangyu; Shahidullah, Mohammad; Rocha, Carmen A.; Strang, Candace; Pfaffinger, Paul J.; Covarrubias, Manuel

    2005-01-01

    Gating of voltage-dependent K+ channels involves movements of membrane-spanning regions that control the opening of the pore. Much less is known, however, about the contributions of large intracellular channel domains to the conformational changes that underlie gating. Here, we investigated the functional role of intracellular regions in Kv4 channels by probing relevant cysteines with thiol-specific reagents. We find that reagent application to the intracellular side of inside-out patches results in time-dependent irreversible inhibition of Kv4.1 and Kv4.3 currents. In the absence or presence of Kv4-specific auxiliary subunits, mutational and electrophysiological analyses showed that none of the 14 intracellular cysteines is essential for channel gating. C110, C131, and C132 in the intersubunit interface of the tetramerization domain (T1) are targets responsible for the irreversible inhibition by a methanethiosulfonate derivative (MTSET). This result is surprising because structural studies of Kv4-T1 crystals predicted protection of the targeted thiolate groups by constitutive high-affinity Zn2+ coordination. Also, added Zn2+ or a potent Zn2+ chelator (TPEN) does not significantly modulate the accessibility of MTSET to C110, C131, or C132; and furthermore, when the three critical cysteines remained as possible targets, the MTSET modification rate of the activated state is ∼200-fold faster than that of the resting state. Biochemical experiments confirmed the chemical modification of the intact α-subunit and the purified tetrameric T1 domain by MTS reagents. These results conclusively demonstrate that the T1T1 interface of Kv4 channels is functionally active and dynamic, and that critical reactive thiolate groups in this interface may not be protected by Zn2+ binding. PMID:15955876

  3. Total (1)H NMR assignment of 3β-acetoxypregna-5,16-dien-20-one.

    PubMed

    Becerra-Martinez, Elvia; Ramírez-Gualito, Karla E; Pérez-Hernández, Nury; Joseph-Nathan, Pedro

    2015-12-01

    This work describes the total and unambiguous assignment of the 750 MHz (1)H NMR spectrum of 3β-acetoxypregna-5,16-dien-20-one or 16-DPA (1), the well-known intermediate utilized in the synthesis of biological important commercial steroids. The task was accomplished by extracting the coupling constant values in the overlapped spectrum region by HSQC, and using these values in the (1)H iterative full spin analysis integrated in the PERCH NMR software. Comparison of the experimental vicinal coupling constants of 1 with the values calculated using Altona provides an excellent correlation. The same procedure, when applied to the published data of progesterone (2) and testosterone (3), afforded an acceptable correlation for 2 and a poor correlation for 3. In the last case, this suggested the reassignment of all four vicinal coupling constants for the methylene signals at the C-15 and C-16 positions, demonstrating the utility of this methodology. PMID:26476187

  4. Interhospital CT image communication: T-1 line versus courier service

    NASA Astrophysics Data System (ADS)

    Lou, Shyhliang A.; Huang, H. K.; Bazzill, Todd M.; Gould, Robert G.; Dillon, William P.; Schomer, Barbara G.

    1995-05-01

    The Mount Zion Hospital (MZH) in San Francisco, Calif. is associated with the University of California at San Francisco (UCSF) medical center. These hospitals are approximately two miles apart. The UCSF radiology department supports specialty image reading for MZH daily. The major issue involved with this service is the access of patient images. Currently, the patient image access is through two ways: (1) inter-hospital travel, and (2) image delivery. Both methods are neither efficient nor economic. If patient images can be transferred from MZH to UCSF to be viewed in digital form in a reasonable time period, the issue of patient image accession can be resolved. This study attempts to use an available digital communication technology, a T-1 line, to verify this hypothesis. The study is centered on the comparison between the T-1 line and courier service with respect to cost and image delivery performance. This comparison study focuses on CT images with an emphasis on neuroradiology application.

  5. [Management of T1a vocal fold carcinoma].

    PubMed

    Reiter, R; Brosch, S; Smith, E; Pickhard, A

    2013-12-01

    About 2/3 of the larynx carcinomas affect the vocal chords. The main risk factor is smoking. Carcinomas in this localisation often arise from leukoplakias with dysplasia. A typical symptom is dysphonia. Arrest of vibration in microlaryngostroboscopy is a hint that a carcinoma could be present. Transoral laser cordectomy or radiotherapy show equivalent oncological results and results in quality of voice in the treatment of vocal fold carcinoma (T1a). As lymph node and distant metastasis are very rare, follow-up can concentrate on microlaryngoscopy. In case of a suspicious area on the vocal fold, biopsy of the affected tissue is needed to plan correct treatment. The prognosis of the T1 vocal chord carcinoma is quite good with a 5-year survival rate of almost 100%. PMID:23929210

  6. Response of sensitive human ataxia and resistant T-1 cell lines to accelerated heavy ions

    SciTech Connect

    Tobias, C.A.; Blakely, E.A.; Chang, P.Y.; Lommel, L.; Roots, R.

    1983-07-01

    The radiation dose responses of fibroblast from a patient with Ataxia telangiectasis (AT-2SF) and an established line of human T-1 cells were studied. Nearly monoenergetic accelerated neon and argon ions were used at the Berkeley Bevalac with various residual range values. The LET of the particles varied from 30 keV/..mu..m to over 1000 keV/..mu..m. All Ataxia survival curves were exponential functions of the dose. Their radiosensitivity reached peak values at 100 to 200 keV/..mu..m. Human T-1 cells have effective sublethal damage repair as has been evidenced by split dose experiments, and they are much more resistant to low LET than to high LET radiation. The repair-misrepair model has been used to interpret these results. We have obtained mathematical expressions that describe the cross sections and inactivation coefficients for both human cell lines as a function of the LET and the type of particle used. The results suggest either that high-LET particles induce a greater number of radiolesions per track or that heavy-ions at high LET induce lesions that kill cells more effectively and that are different from those produced at low LET. We assume that the lesions induced in T-1 and Ataxia cells are qualitatively similar and that each cell line attempts to repair these lesions. The result in most irradiated Ataxia cells, however, is either lethal misrepair or incomplete repair leading to cell death. 63 references, 10 figures, 1 table.

  7. T1 assessment of hip joint cartilage following intra-articular gadolinium injection: a pilot study.

    PubMed

    Bittersohl, Bernd; Hosalkar, Harish S; Kim, Young-Jo; Werlen, Stefan; Trattnig, Siegfried; Siebenrock, Klaus A; Mamisch, Tallal C

    2010-10-01

    This pilot study defines the feasibility of cartilage assessment in symptomatic femoroacetabular impingement patients using intra-articular delayed gadolinium-enhanced MRI of cartilage (ia-dGEMRIC). Nine patients were scanned preliminary to study the contrast infiltration process into hip joint cartilage. Twenty-seven patients with symptomatic femoroacetabular impingement were subsequently scanned with intra-articular delayed gadolinium-enhanced MRI of cartilage. These T(1) findings were correlated to morphological findings. Zonal variations were studied. This pilot study demonstrates a significant difference between the pre- and postcontrast T(1) values (P < 0.001) remaining constant for 45 min. We noted higher mean T(1) values in morphologically normal-appearing cartilage than in damaged cartilage, which was statistically significant for all zones except the anterior-superior zone. Intraobserver (0.972) and interobserver correlation coefficients (0.933) were statistically significant. This study outlines the feasibility of intra-articular delayed gadolinium-enhanced MRI of cartilage for assessment of cartilage changes in patients with femoroacetabular impingement. It can also define the topographic extent and differing severities of cartilage damage. PMID:20872764

  8. Geometrically confined ultrasmall gadolinium oxide nanoparticles boost the T1 contrast ability

    NASA Astrophysics Data System (ADS)

    Ni, Kaiyuan; Zhao, Zhenghuan; Zhang, Zongjun; Zhou, Zijian; Yang, Li; Wang, Lirong; Ai, Hua; Gao, Jinhao

    2016-02-01

    High-performance magnetic resonance imaging (MRI) contrast agents and novel contrast enhancement strategies are urgently needed for sensitive and accurate diagnosis. Here we report a strategy to construct a new T1 contrast agent based on the Solomon-Bloembergen-Morgan (SBM) theory. We loaded the ultrasmall gadolinium oxide nanoparticles into worm-like interior channels of mesoporous silica nanospheres (Gd2O3@MSN nanocomposites). This unique structure endows the nanocomposites with geometrical confinement, high molecular tumbling time, and a large coordinated number of water molecules, which results in a significant enhancement of the T1 contrast with longitudinal proton relaxivity (r1) as high as 45.08 mM-1 s-1. Such a high r1 value of Gd2O3@MSN, compared to those of ultrasmall Gd2O3 nanoparticles and gadolinium-based clinical contrast agents, is mainly attributed to the strong geometrical confinement effect. This strategy provides new guidance for developing various high-performance T1 contrast agents for sensitive imaging and disease diagnosis.High-performance magnetic resonance imaging (MRI) contrast agents and novel contrast enhancement strategies are urgently needed for sensitive and accurate diagnosis. Here we report a strategy to construct a new T1 contrast agent based on the Solomon-Bloembergen-Morgan (SBM) theory. We loaded the ultrasmall gadolinium oxide nanoparticles into worm-like interior channels of mesoporous silica nanospheres (Gd2O3@MSN nanocomposites). This unique structure endows the nanocomposites with geometrical confinement, high molecular tumbling time, and a large coordinated number of water molecules, which results in a significant enhancement of the T1 contrast with longitudinal proton relaxivity (r1) as high as 45.08 mM-1 s-1. Such a high r1 value of Gd2O3@MSN, compared to those of ultrasmall Gd2O3 nanoparticles and gadolinium-based clinical contrast agents, is mainly attributed to the strong geometrical confinement effect. This strategy

  9. Highly monodisperse low-magnetization magnetite nanocubes as simultaneous T1-T2 MRI contrast agents

    NASA Astrophysics Data System (ADS)

    Sharma, V. K.; Alipour, A.; Soran-Erdem, Z.; Aykut, Z. G.; Demir, H. V.

    2015-06-01

    We report the first study of highly monodisperse and crystalline iron oxide nanocubes with sub-nm controlled size distribution (9.7 +/- 0.5 nm in size) that achieve simultaneous contrast enhancement in both T1- and T2-weighted magnetic resonance imaging (MRI). Here, we confirmed the magnetite structure of iron oxide nanocubes by X-ray diffraction (XRD), selected area electron diffraction (SAED) pattern, optical absorption and Fourier transformed infrared (FT-IR) spectra. These magnetite nanocubes exhibit superparamagnetic and paramagnetic behavior simultaneously by virtue of their finely controlled shape and size. The magnetic measurements reveal that the magnetic moment values are favorably much lower because of the small size and cubic shape of the nanoparticles, which results in an enhanced spin canting effect. As a proof-of-concept demonstration, we showed their potential as dual contrast agents for both T1- and T2-weighted MRI via phantom studies, in vivo imaging and relaxivity measurements. Therefore, these low-magnetization magnetite nanocubes, while being non-toxic and bio-compatible, hold great promise as excellent dual-mode T1 and T2 contrast agents for MRI.We report the first study of highly monodisperse and crystalline iron oxide nanocubes with sub-nm controlled size distribution (9.7 +/- 0.5 nm in size) that achieve simultaneous contrast enhancement in both T1- and T2-weighted magnetic resonance imaging (MRI). Here, we confirmed the magnetite structure of iron oxide nanocubes by X-ray diffraction (XRD), selected area electron diffraction (SAED) pattern, optical absorption and Fourier transformed infrared (FT-IR) spectra. These magnetite nanocubes exhibit superparamagnetic and paramagnetic behavior simultaneously by virtue of their finely controlled shape and size. The magnetic measurements reveal that the magnetic moment values are favorably much lower because of the small size and cubic shape of the nanoparticles, which results in an enhanced spin

  10. Early postnatal myelin content estimate of white matter via T1w/T2w ratio

    NASA Astrophysics Data System (ADS)

    Lee, Kevin; Cherel, Marie; Budin, Francois; Gilmore, John; Zaldarriaga Consing, Kirsten; Rasmussen, Jerod; Wadhwa, Pathik D.; Entringer, Sonja; Glasser, Matthew F.; Van Essen, David C.; Buss, Claudia; Styner, Martin

    2015-03-01

    To develop and evaluate a novel processing framework for the relative quantification of myelin content in cerebral white matter (WM) regions from brain MRI data via a computed ratio of T1 to T2 weighted intensity values. We employed high resolution (1mm3 isotropic) T1 and T2 weighted MRI from 46 (28 male, 18 female) neonate subjects (typically developing controls) scanned on a Siemens Tim Trio 3T at UC Irvine. We developed a novel, yet relatively straightforward image processing framework for WM myelin content estimation based on earlier work by Glasser, et al. We first co-register the structural MRI data to correct for motion. Then, background areas are masked out via a joint T1w and T2 foreground mask computed. Raw T1w/T2w-ratios images are computed next. For purpose of calibration across subjects, we first coarsely segment the fat-rich facial regions via an atlas co-registration. Linear intensity rescaling based on median T1w/T2w-ratio values in those facial regions yields calibrated T1w/T2wratio images. Mean values in lobar regions are evaluated using standard statistical analysis to investigate their interaction with age at scan. Several lobes have strongly positive significant interactions of age at scan with the computed T1w/T2w-ratio. Most regions do not show sex effects. A few regions show no measurable effects of change in myelin content change within the first few weeks of postnatal development, such as cingulate and CC areas, which we attribute to sample size and measurement variability. We developed and evaluated a novel way to estimate white matter myelin content for use in studies of brain white matter development.

  11. Localized double-quantum-filtered 1H NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Thomas, M. A.; Hetherington, H. P.; Meyerhoff, D. J.; Twieg, D. B.

    The image-guided in vivo spectroscopic (ISIS) pulse sequence has been combined with a double-quantum-filter scheme in order to obtain localized and water-suppressed 1H NMR spectra of J-coupled metabolites. The coherence-transfer efficiency associated with the DQ filter for AX and A 3X spin systems is described. Phantom results of carnosine, alanine, and ethanol in aqueous solution are presented. For comparison, the 1H NMR spectrum of alanine in aqueous solution with the binomial (1331, 2662) spin-echo sequence is also shown.

  12. Zn2+-dependent Redox Switch in the Intracellular T1-T1 Interface of a Kv Channel*†

    PubMed Central

    Wang, Guangyu; Strang, Candace; Pfaffinger, Paul J.; Covarrubias, Manuel

    2008-01-01

    The thiol-based redox regulation of proteins plays a central role in cellular signaling. Here, we investigated the redox regulation at the Zn2+ binding site (HX5CX20CC) in the intracellular T1-T1 inter-subunit interface of a Kv4 channel. This site undergoes conformational changes coupled to voltage-dependent gating, which may be sensitive to oxidative stress. The main results show that internally applied nitric oxide (NO) inhibits channel activity profoundly. This inhibition is reversed by reduced glutathione and suppressed by intracellular Zn2+, and at least two Zn2+ site cysteines are required to observe the NO-induced inhibition (Cys-110 from one subunit and Cys-132 from the neighboring subunit). Biochemical evidence suggests strongly that NO induces a disulfide bridge between Cys-110 and Cys-132 in intact cells. Finally, further mutational studies suggest that intra-subunit Zn2+ coordination involving His-104, Cys-131, and Cys-132 protects against the formation of the inhibitory disulfide bond. We propose that the interfacial T1 Zn2+ site of Kv4 channels acts as a Zn2+-dependent redox switch that may regulate the activity of neuronal and cardiac A-type K+ currents under physiological and pathological conditions. PMID:17331952

  13. UV-vis, IR and 1H NMR spectroscopic studies and characterization of ionic-pair crystal violet-oxytetracycline

    NASA Astrophysics Data System (ADS)

    Orellana, Sandra; Soto, César; Toral, M. Inés

    2010-01-01

    The present study shows the formation and characterization of the ionic-pair between the antibiotic oxytetracycline and the dye crystal violet in ammonia solution pH 9.0 ± 0.2 extracted into chloroform. The characterization was demonstrated using UV-vis spectrophotometry, 1H NMR, measurement of relaxation times T1 and IR spectroscopy, using a comparison between the signals of individual pure compounds with the signals with the mixture CV-OTC in different alkaline media. The formation of ionic-pair was also corroborated by new signals and chemical shifts. (2D) NMR spectroscopy experiments show that the interaction is electrostatic.

  14. Applications of 1H-NMR to Biodiesel Research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biodiesel is an alternative diesel fuel derived from vegetable oils, animal fats, or used cooking oils. It is produced by reacting these materials with an alcohol in the presence of a catalyst to give the corresponding mono-alkyl esters. 1H-NMR is a routine analytical method that has been used for...

  15. Carotid dosimetry for T1 glottic cancer radiotherapy

    PubMed Central

    Lim, C C; Whitehurst, P; Thomson, D; Ho, K F; Lowe, M; Sykes, A; Lee, LW; Yap, B; Slevin, N

    2014-01-01

    Objective: Radiotherapy for T1 glottic cancer is commonly delivered using a lateral parallel opposed pair of megavoltage photon fields. There is increasing reported evidence of cerebrovascular events due to radiation-induced carotid stenosis. An alternative field arrangement is to use an anterior oblique technique. This study compares the carotid dosimetry between the two techniques and reviews the evidence for the risk of radiation-induced vascular events. Methods: The radiotherapy plans of 10 patients with T1 glottic cancer treated with an anterior oblique technique were examined for carotid dose. Alternative plans were then created using a parallel opposed pair of fields and the dose to the carotids compared. All patients received 50 Gy in 16 fractions treating once daily, for 5 days in a week. Results: The average of the mean dose to the carotids with the anterior oblique technique was 21 Gy compared with 37 Gy using the lateral parallel opposed pair arrangement (p < 0.0001). Conclusion: An anterior oblique field arrangement for the treatment of T1 glottic cancer results in a significantly lower radiation dose to the carotid arteries, which may be clinically important in terms of reducing the risk of cerebrovascular events in long-term survivors. Advances in knowledge: Although the anterior oblique technique for treating early glottic cancers is well described, and it is predictable that the dose received by the carotid arteries should be lower with this technique, to our knowledge this is the first study to quantify that reduction in dose with a series of patients. PMID:24628251

  16. Efficient dipolar double quantum filtering under magic angle spinning without a 1H decoupling field

    NASA Astrophysics Data System (ADS)

    Courtney, Joseph M.; Rienstra, Chad M.

    2016-08-01

    We present a systematic study of dipolar double quantum (DQ) filtering in 13C-labeled organic solids over a range of magic-angle spinning rates, using the SPC-n recoupling sequence element with a range of n symmetry values from 3 to 11. We find that efficient recoupling can be achieved for values n ⩾ 7, provided that the 13C nutation frequency is on the order of 100 kHz or greater. The decoupling-field dependence was investigated and explicit heteronuclear decoupling interference conditions identified. The major determinant of DQ filtering efficiency is the decoupling interference between 13C and 1H fields. For 13C nutation frequencies greater than 75 kHz, optimal performance is observed without an applied 1H field. At spinning rates exceeding 20 kHz, symmetry conditions as low as n = 3 were found to perform adequately.

  17. Efficient dipolar double quantum filtering under magic angle spinning without a (1)H decoupling field.

    PubMed

    Courtney, Joseph M; Rienstra, Chad M

    2016-08-01

    We present a systematic study of dipolar double quantum (DQ) filtering in (13)C-labeled organic solids over a range of magic-angle spinning rates, using the SPC-n recoupling sequence element with a range of n symmetry values from 3 to 11. We find that efficient recoupling can be achieved for values n⩾7, provided that the (13)C nutation frequency is on the order of 100kHz or greater. The decoupling-field dependence was investigated and explicit heteronuclear decoupling interference conditions identified. The major determinant of DQ filtering efficiency is the decoupling interference between (13)C and (1)H fields. For (13)C nutation frequencies greater than 75kHz, optimal performance is observed without an applied (1)H field. At spinning rates exceeding 20kHz, symmetry conditions as low as n=3 were found to perform adequately. PMID:27314744

  18. The T1-T2 study : evolution of aeorsol properties downwind of Mexico City.

    SciTech Connect

    Doran, J. C.; Barnard, J. C.; Arnold, W. P.; Cary, C.; Coulter, R.; Fast, J. D.; Kassianov, E. I.; Kleinman, L.; Laulainen, N. S.; Martin, T.; Paredes-Miranda, G.; Pekour, M. S.; Shaw, W. J; Smith, D. F.; Springston, S. R.; Yu, X.-Y.; Environmental Science Division; PNNL; Desert Reseach Inst.; Sunset Lab., Inc.; BNL

    2007-01-01

    As part of a major atmospheric chemistry and aerosol field program carried out in March 2006, a study was conducted in the area to the north and northeast of Mexico City to investigate the evolution of aerosols and their associated optical properties in the first few hours after their emission. The focus of the T1-T2 aerosol study was to investigate changes in the specific absorption a{sub ABS} (absorption per unit mass, with unit of m{sup 2} g{sup -1}) of black carbon as it aged and became coated with compounds such as sulfate and organic carbon, evolving from an external to an internal mixture. Such evolution has been reported in previous studies. The T1 site was located just to the north of the Mexico City metropolitan area; the T2 site was situated approximately 35 km farther to the northeast. Nephelometers, particle soot absorption photometers, photoacoustic absorption spectrometers, and organic and elemental carbon analyzers were used to measure the optical properties of the aerosols and the carbon concentrations at each of the sites. Radar wind profilers and radiosonde systems helped to characterize the meteorology and to identify periods when transport from Mexico City over T1 and T2 occurred. Organic and elemental carbon concentrations at T1 showed diurnal cycles reflecting the nocturnal and early morning buildup from nearby sources, while concentrations at T2 appeared to be more affected by transport from Mexico City. Specific absorption during transport periods was lower than during other times, consistent with the likelihood of fresher emissions being found when the winds blew from Mexico City over T1 and T2. The specific absorption at T2 was larger than at T1, which is also consistent with the expectation of more aged particles with encapsulated black carbon being found at the more distant location. In situ measurements of single scattering albedo with an aircraft and a ground station showed general agreement with column-averaged values derived from

  19. The T1-T2 Study: Evolution of Aerosol Properties Downwind of Mexico City

    SciTech Connect

    Doran, J C; Barnard, James C; Arnott, W P; Cary, R; Coulter, Richard L; Fast, Jerome D; Kassianov, Evgueni I; Kleinman, Lawrence I; Laulainen, Nels S; Martin, Tim J; Paredes-Miranda, Guadalupe L; Pekour, Mikhail S; Shaw, William J; Smith, D F; Springston, Stephen R; Yu, Xiao-Ying

    2007-03-23

    As part of a major atmospheric chemistry and aerosol field program carried out in March of 2006, a study was conducted in the area to the north and northeast of Mexico City to investigate the evolution of aerosols and their associated optical properties in the first few hours after their emission. The focus of the T1-T2 aerosol study was to investigate changes in the specific absorption αABS (absorption per unit mass, with unit of m2g-1) of black carbon as it aged and became coated with compounds such as sulfate and organic carbon, evolving from an external to an internal mixture. Such evolution has been reported in previous studies. The T1 site was located just to the north of the Mexico City metropolitan area; the T2 site was situated approximately 35 km farther to the northeast. Nephelometers, particle soot absorption photometers, photoacoustic absorption photometers, and organic and elemental carbon analyzers were used to measure the optical properties of the aerosols and the carbon concentrations at each of the sites. Radar wind profilers and radiosonde systems helped to characterize the meteorology and to identify periods when transport from Mexico City over T1 and T2 occurred. Organic and elemental carbon concentrations at T1 showed diurnal cycles reflecting the nocturnal and early morning buildup from nearby sources, while concentrations at T2 appeared to be more affected by transport from Mexico City. Specific absorption during transport periods was lower than during other times, consistent with the likelihood of fresher emissions being found when the winds blew from Mexico City over T1 and T2. The specific absorption at T2 was larger than at T1, which is also consistent with the expectation of more aged particles with encapsulated black carbon being found at the more distant location. In situ measurements of single scattering albedo with an aircraft and a ground station showed general agreement with column-averaged values derived from rotating shadowband

  20. T-1 Test Program Ver. 6.0.1

    SciTech Connect

    Perlinski, Anthony W.

    2004-05-21

    The software allows for easy setup and testing of a variety of RF Electronic Sensor Platforms (ESPs). The software interprets RF messages from the ESP and displays the information in a graphical user interface. This program is used primarily for testing of the T-1 Electronic Sensor Platform. The software imports Electronic Tag Data files which are created from the Electronic Sensor Platform Programmer (ESPP). The software will automatically add sensors to its database when a RF message s received that the program recognizes. Any data that is generated can be stored to a file for later analysis.

  1. The electronics system of the TOTEM T1 telescope

    NASA Astrophysics Data System (ADS)

    Minutoli, S.; Bozzo, M.; Ferro, F.; Lo Vetere, M.; Robutti, E.

    2013-08-01

    The T1 detector of the TOTEM experiment is devoted to the measurement of the inelastic rate of proton-proton interactions at the LHC. It is made of Cathode Strip Chambers. The complete electronic chains of front-end, readout and trigger are presented here. The electronics system has been developed keeping into account the hostile environment from the point of view of both radiation and magnetic field. Dedicated VLSI circuits have been extensively used in order to optimize space and power consumption.

  2. The TOTEM T1 read out card motherboard

    NASA Astrophysics Data System (ADS)

    Minutoli, S.; Lo Vetere, M.; Robutti, E.

    2010-12-01

    This article describes the Read Out Card (ROC) motherboard, which is the main component of the T1 forward telescope front-end electronic system. The ROC main objectives are to acquire tracking data and trigger information from the detector. It performs data conversion from electrical to optical format and transfers the data streams to the next level of the system and it implements Slow Control modules which are able to receive, decode and distribute the LHC machine low jitter clock and fast command. The ROC also provides a spy mezzanine connection based on programmable FPGA and USB2.0 for laboratory and portable DAQ debugging system.

  3. T-1 Test Program Ver. 6.0.1

    Energy Science and Technology Software Center (ESTSC)

    2004-05-21

    The software allows for easy setup and testing of a variety of RF Electronic Sensor Platforms (ESPs). The software interprets RF messages from the ESP and displays the information in a graphical user interface. This program is used primarily for testing of the T-1 Electronic Sensor Platform. The software imports Electronic Tag Data files which are created from the Electronic Sensor Platform Programmer (ESPP). The software will automatically add sensors to its database when amore » RF message s received that the program recognizes. Any data that is generated can be stored to a file for later analysis.« less

  4. Calibration of myocardial T2 and T1 against iron concentration

    PubMed Central

    2014-01-01

    Background The assessment of myocardial iron using T2* cardiovascular magnetic resonance (CMR) has been validated and calibrated, and is in clinical use. However, there is very limited data assessing the relaxation parameters T1 and T2 for measurement of human myocardial iron. Methods Twelve hearts were examined from transfusion-dependent patients: 11 with end-stage heart failure, either following death (n = 7) or cardiac transplantation (n = 4), and 1 heart from a patient who died from a stroke with no cardiac iron loading. Ex-vivo R1 and R2 measurements (R1 = 1/T1 and R2 = 1/T2) at 1.5 Tesla were compared with myocardial iron concentration measured using inductively coupled plasma atomic emission spectroscopy. Results From a single myocardial slice in formalin which was repeatedly examined, a modest decrease in T2 was observed with time, from mean (±SD) 23.7 ± 0.93 ms at baseline (13 days after death and formalin fixation) to 18.5 ± 1.41 ms at day 566 (p < 0.001). Raw T2 values were therefore adjusted to correct for this fall over time. Myocardial R2 was correlated with iron concentration [Fe] (R2 0.566, p < 0.001), but the correlation was stronger between LnR2 and Ln[Fe] (R2 0.790, p < 0.001). The relation was [Fe] = 5081•(T2)-2.22 between T2 (ms) and myocardial iron (mg/g dry weight). Analysis of T1 proved challenging with a dichotomous distribution of T1, with very short T1 (mean 72.3 ± 25.8 ms) that was independent of iron concentration in all hearts stored in formalin for greater than 12 months. In the remaining hearts stored for <10 weeks prior to scanning, LnR1 and iron concentration were correlated but with marked scatter (R2 0.517, p < 0.001). A linear relationship was present between T1 and T2 in the hearts stored for a short period (R2 0.657, p < 0.001). Conclusion Myocardial T2 correlates well with myocardial iron concentration, which raises the possibility that T2 may provide additive

  5. Geometrically confined ultrasmall gadolinium oxide nanoparticles boost the T(1) contrast ability.

    PubMed

    Ni, Kaiyuan; Zhao, Zhenghuan; Zhang, Zongjun; Zhou, Zijian; Yang, Li; Wang, Lirong; Ai, Hua; Gao, Jinhao

    2016-02-14

    High-performance magnetic resonance imaging (MRI) contrast agents and novel contrast enhancement strategies are urgently needed for sensitive and accurate diagnosis. Here we report a strategy to construct a new T1 contrast agent based on the Solomon-Bloembergen-Morgan (SBM) theory. We loaded the ultrasmall gadolinium oxide nanoparticles into worm-like interior channels of mesoporous silica nanospheres (Gd2O3@MSN nanocomposites). This unique structure endows the nanocomposites with geometrical confinement, high molecular tumbling time, and a large coordinated number of water molecules, which results in a significant enhancement of the T1 contrast with longitudinal proton relaxivity (r1) as high as 45.08 mM(-1) s(-1). Such a high r1 value of Gd2O3@MSN, compared to those of ultrasmall Gd2O3 nanoparticles and gadolinium-based clinical contrast agents, is mainly attributed to the strong geometrical confinement effect. This strategy provides new guidance for developing various high-performance T1 contrast agents for sensitive imaging and disease diagnosis. PMID:26814592

  6. T1 characteristics of interstitial pulmonary fibrosis on 3T MRI—a predictor of early interstitial change?

    PubMed Central

    Tse, Matthew; Kershaw, Lucy; Semple, Scott; Schembri, Nicola; Chin, Calvin; Murchison, John T.; Hirani, Nik; van Beek, Edwin J. R.

    2016-01-01

    Background Computed tomography (CT) is routinely used for diagnosis and characterisation of idiopathic pulmonary fibrosis (IPF). The technique however has limited sensitivity in detection and monitoring of early fibrotic changes. The aim of this study was to evaluate T1 characteristics in the radiologically diseased lung parenchyma in IPF patient compared to apparently normal parenchyma in both interstitial lung disease (ILD) patients and healthy volunteers and to investigate the feasibility of the technique in prediction of early fibrotic lung changes that may not be visible on CT. Methods Ten patients with IPF underwent high resolution computed tomography (HRCT) and magnetic resonance imaging (MRI) on the same day of attendance. 3T MRI was repeated in seven patients with IPF to test the reproducibility of results. The control group included healthy volunteers (n=10). A modified look-locker inversion-recovery (MOLLI) sequence (124×192 acquisition matrix; 8 mm slice) was performed during a 15–20 s breathhold in a single slice. The position of MR slice was pre-selected where there was CT evidence of normal and fibrotic lung. MOLLI imaging was performed prior to the contrast administration, and at 15, 25, 30 and 35 min post Gadolinium. The imaging data were then processed with a curve-fitting technique to estimate T1 values. T1 values of the apparent fibrotic and normal lung in IPF patients and normal lung were compared. Results Fibrotic lung had a higher pre-contrast T1 than either morphologically normal lung in ILD patients or control lung (P=0.02) in healthy volunteers (1309±123, 1069±71, and 1011±172 ms, respectively). Morphologically normal lung T1 and control lung T1 were not significantly different pre-contrast, however, at 10 min after administration of Gadolinium, control lung had a significantly shorter T1 than either fibrotic or morphologically normal lung (494±34, 670±63, and 619±41 ms, respectively; P=0.001). T1 for fibrotic lung continued to

  7. Investigations of the νT=1 exciton condensate

    NASA Astrophysics Data System (ADS)

    Wiersma, R. D.; Lok, J. G. S.; Tiemann, L.; Dietsche, W.; von Klitzing, K.; Schuh, D.; Wegscheider, W.

    2006-12-01

    Recent experiments on quantum Hall bilayers in the vicinity of total filling factor 1 ( νT=1) have revealed many exciting observations characteristic of a superfluidic exciton condensate. We report on our experimental work involving the νT=1 exciton condensate in independently contacted bilayer two-dimensional electron systems. We observe previously reported phenomena as a zero-bias resonant tunneling peak, a quantized Hall drag resistivity, and in counter-flow configuration, the near vanishing of both ρxx and ρxy resistivity components. At balanced electron densities in the layers, we find for both drag and counter-flow current configurations, thermally activated transport with a monotonic increase of the activation energy for d/ℓB<1.65 with activation energies up to 0.4 K. In the imbalanced system the activation energies show a striking asymmetry around the balance point, implying that the gap to charge excitations is considerably different in the separate layers that form the bilayer condensate. This indicates that the measured activation energy is neither the binding energy of the excitons, nor their condensation energy.

  8. Investigations of the νT=1 Exciton Condensate

    NASA Astrophysics Data System (ADS)

    Wiersma, R. D.; Lok, J. G. S.; Tiemann, L.; Dietsche, W.; von Klitzing, K.; Wegscheider, W.; Schuh, D.

    Recent experiments on quantum Hall bilayers in the vicinity of total filling factor 1 (νT=1) have revealed the possibility of a superfluidic exciton condensate. We report on our experimental work involving the νT=1 exciton condensate in independently contacted bilayer two-dimensional electron systems. We reproduce the previously reported zero bias resonant tunneling peak, a quantized Hall drag resistivity, and in counter-flow configuration, the near vanishing of both ρxx and ρxy resistivity components. At balanced electron densities in the layers, we find for both drag and counter-flow current configurations, thermally activated transport with a monotonic increase of the activation energy for d/ℓB < 1.65 with activation energies up to 0.4 K. In the imbalanced system the activation energies show a striking asymmetry around the balance point, implying that the gap to charge excitations is considerably different in the separate layers that form the bilayer condensate. This indicates that the measured activation energy is neither the binding energy of the excitons, nor their condensation energy. We establish a phase diagram of the excitonic condensate showing the enhancement of this state at slight imbalances.

  9. Phosphorescence excitation spectrum of the T1(n,π*)<--S0 transition of 4H-pyran-4-one

    NASA Astrophysics Data System (ADS)

    Hoffelt, Laura M.; Springer, Mitchell G.; Drucker, Stephen

    2008-03-01

    The phosphorescence excitation (PE) spectrum of 4H-pyran-4-one (4PN) vapor at 40-50°C was recorded near 366nm. The most intense vibronic feature in this region of the spectrum is the T1(n,π*)←S0 origin band. The value of ν0 for the 000 transition was determined to be 27291.5cm-1 by comparing the observed spectrum to a simulation in the T1←S0 origin-band region. Attached to the origin band in the PE spectrum are several Δv =0 sequence bands involving low-frequency ring modes. From the positions of these bands, together with the known ground-state combination differences, fundamental frequencies for ν18' (ring bending), ν13' (ring twisting), and ν10' (in-plane ring deformation) in the T1(n,π*) excited state were determined to be 126, 269, and 288cm-1, respectively. These values represent drops of 15%, 32%, and 43%, compared to the respective fundamental frequencies in the S0 state. The changes in these ring frequencies indicate that the effects of T1(n,π*)←S0 excitation extend beyond the nominal carbonyl chromophore and involve the conjugated ring atoms as well. The delocalization may be more extensive for T1(n,π*) than for S1(n,π*) excitation.

  10. Adenosine Stress and Rest T1 Mapping Can Differentiate Between Ischemic, Infarcted, Remote, and Normal Myocardium Without the Need for Gadolinium Contrast Agents

    PubMed Central

    Liu, Alexander; Wijesurendra, Rohan S.; Francis, Jane M.; Robson, Matthew D.; Neubauer, Stefan; Piechnik, Stefan K.; Ferreira, Vanessa M.

    2016-01-01

    Objectives The aim of this study was to evaluate the potential of T1 mapping at rest and during adenosine stress as a novel method for ischemia detection without the use of gadolinium contrast. Background In chronic coronary artery disease (CAD), accurate detection of ischemia is important because targeted revascularization improves clinical outcomes. Myocardial blood volume (MBV) may be a more comprehensive marker of ischemia than myocardial blood flow. T1 mapping using cardiac magnetic resonance (CMR) is highly sensitive to changes in myocardial water content, including MBV. We propose that T1 mapping at rest and during adenosine vasodilatory stress can detect MBV changes in normal and diseased myocardium in CAD. Methods Twenty normal controls (10 at 1.5-T; 10 at 3.0-T) and 10 CAD patients (1.5-T) underwent conventional CMR to assess for left ventricular function (cine), infarction (late gadolinium enhancement [LGE]) and ischemia (myocardial perfusion reserve index [MPRI] on first-pass perfusion imaging during adenosine stress). These were compared to novel pre-contrast stress/rest T1 mapping using the Shortened Modified Look-Locker Inversion recovery technique, which is heart rate independent. T1 values were derived for normal myocardium in controls and for infarcted, ischemic, and remote myocardium in CAD patients. Results Normal myocardium in controls (normal wall motion, MPRI, no LGE) showed normal resting T1 (954 ± 19 ms at 1.5-T; 1,189 ± 34 ms at 3.0-T) and significant positive T1 reactivity during adenosine stress compared to baseline (6.2 ± 0.5% at 1.5-T; 6.3 ± 1.1% at 3.0-T; all p < 0.0001). Infarcted myocardium showed the highest resting T1 of all tissue classes (1,442 ± 84 ms), without significant T1 reactivity (0.2 ± 1.5%). Ischemic myocardium showed elevated resting T1 compared to normal (987 ± 17 ms; p < 0.001) without significant T1 reactivity (0.2 ± 0.8%). Remote myocardium, although having comparable resting T1 to normal (955 ± 17 ms

  11. 4D prediction of protein (1)H chemical shifts.

    PubMed

    Lehtivarjo, Juuso; Hassinen, Tommi; Korhonen, Samuli-Petrus; Peräkylä, Mikael; Laatikainen, Reino

    2009-12-01

    A 4D approach for protein (1)H chemical shift prediction was explored. The 4th dimension is the molecular flexibility, mapped using molecular dynamics simulations. The chemical shifts were predicted with a principal component model based on atom coordinates from a database of 40 protein structures. When compared to the corresponding non-dynamic (3D) model, the 4th dimension improved prediction by 6-7%. The prediction method achieved RMS errors of 0.29 and 0.50 ppm for Halpha and HN shifts, respectively. However, for individual proteins the RMS errors were 0.17-0.34 and 0.34-0.65 ppm for the Halpha and HN shifts, respectively. X-ray structures gave better predictions than the corresponding NMR structures, indicating that chemical shifts contain invaluable information about local structures. The (1)H chemical shift prediction tool 4DSPOT is available from http://www.uku.fi/kemia/4dspot . PMID:19876601

  12. 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. PMID:17387512

  13. Laundering and Deinking Applications of 1H NMR Imaging

    NASA Astrophysics Data System (ADS)

    Tutunjian, P. N.; Borchardt, J. K.; Prieto, N. E.; Raney, K. H.; Ferris, J. A.

    One-dimensional 1H NMR imaging techniques are used to visualize oil removal from fabrics and paper fibers immersed in aqueous solutions of nonionic detergents. The method provides a unique approach to the study of oil-removal kinetics in nonionic detergent systems where traditional optical techniques fail due to solution turbidity. The only requirement of the NMR experiment is the use of deuterated water in order to selectively image the hydrocarbon phase. Preliminary applications to laundering and paper deinking are discussed.

  14. MTR and In-vivo 1H-MRS studies on mouse brain with parkinson's disease

    NASA Astrophysics Data System (ADS)

    Yoon, Moon-Hyun; Kim, Hyeon-Jin; Chung, Jin-Yeung; Doo, Ah-Reum; Park, Hi-Joon; Kim, Seung-Nam; Choe, Bo-Young

    2012-12-01

    The aim of this study was to investigate whether the changes in the magnetization transfer ratio (MTR) histogram are related to specific characteristics of Parkinson's disease (PD) and to investigate whether the MTR histogram parameters are associated with neurochemical dysfunction by performing in vivo proton magnetic resonance spectroscopy (1H-MRS). MTR and in vivo 1H-MRS studies were performed on control mice (n = 10) and 1-methyl-1,2,3,6-tetrahydropyridine intoxicated mice (n = 10). All the MTR and in vivo 1H-MRS experiments were performed on a 9.4 T MRI/MRS system (Bruker Biospin, Germany) using a standard head coil. The protondensity fast spin echo (FSE) images and the T2-weighted spin echo (SE) images were acquired with no gap. Outer volume suppression (OVS), combined with the ultra-short echo-time stimulated echo acquisition mode (STEAM), was used for the localized in-vivo 1H-MRS. The quantitative analysis of metabolites was performed from the 1H spectra obtained in vivo on the striatum (ST) by using jMRUI (Lyon, France). The peak height of the MTR histograms in the PD model group was significantly lower than that in the control group (p < 0.05). The midbrain MTR values for volume were lower in the PD group than the control group(p < 0.05). The complex peak (Glx: glutamine+glutamate+ GABA)/creatine (Cr) ratio of the right ST in the PD group was significantly increased as compared to that of the control group. The present study revealed that the peak height of the MTR histogram was significantly decreased in the ST and substantia nigra, and a significant increase in the Gl x /Cr ratio was found in the ST of the PD group, as compared with that of the control group. These findings could reflect the early phase of neuronal dysfunction of neurotransmitters.

  15. MAIN-BELT COMET P/2012 T1 (PANSTARRS)

    SciTech Connect

    Hsieh, Henry H.; Kaluna, Heather M.; Yang Bin; Haghighipour, Nader; Micheli, Marco; Denneau, Larry; Jedicke, Robert; Kleyna, Jan; Veres, Peter; Wainscoat, Richard J.; Ansdell, Megan; Elliott, Garrett T.; Keane, Jacqueline V.; Meech, Karen J.; Riesen, Timm E.; Sonnett, Sarah; Novakovic, Bojan; Fitzsimmons, Alan; Moskovitz, Nicholas A.; Sheppard, Scott S.; and others

    2013-07-01

    We present initial results from observations and numerical analyses aimed at characterizing the main-belt comet P/2012 T1 (PANSTARRS). Optical monitoring observations were made between 2012 October and 2013 February using the University of Hawaii 2.2 m telescope, the Keck I telescope, the Baade and Clay Magellan telescopes, Faulkes Telescope South, the Perkins Telescope at Lowell Observatory, and the Southern Astrophysical Research Telescope. The object's intrinsic brightness approximately doubles from the time of its discovery in early October until mid-November and then decreases by {approx}60% between late December and early February, similar to photometric behavior exhibited by several other main-belt comets and unlike that exhibited by disrupted asteroid (596) Scheila. We also used Keck to conduct spectroscopic searches for CN emission as well as absorption at 0.7 {mu}m that could indicate the presence of hydrated minerals, finding an upper limit CN production rate of Q{sub CN} < 1.5 Multiplication-Sign 10{sup 23} mol s{sup -1}, from which we infer a water production rate of Q{sub H{sub 2O}}<5 Multiplication-Sign 10{sup 25} mol s{sup -1}, and no evidence of the presence of hydrated minerals. Numerical simulations indicate that P/2012 T1 is largely dynamically stable for >100 Myr and is unlikely to be a recently implanted interloper from the outer solar system, while a search for potential asteroid family associations reveals that it is dynamically linked to the {approx}155 Myr old Lixiaohua asteroid family.

  16. Europium-engineered iron oxide nanocubes with high T1 and T2 contrast abilities for MRI in living subjects

    NASA Astrophysics Data System (ADS)

    Yang, Lijiao; Zhou, Zijian; Liu, Hanyu; Wu, Changqiang; Zhang, Hui; Huang, Guoming; Ai, Hua; Gao, Jinhao

    2015-04-01

    Magnetic resonance imaging (MRI) contrast agents with both positive (T1) and negative (T2) contrast abilities are needed in clinical diagnosis for fault-free accurate detection of lesions. We report a facile synthesis of europium-engineered iron oxide (EuIO) nanocubes as T1 and T2 contrast agents for MRI in living subjects. The Eu(iii) oxide-embedded iron oxide nanoparticles significantly increase the T1 relaxivity with an enhanced positive contrast effect. EuIO nanocubes with 14 nm in diameter showed a high r1 value of 36.8 mM-1 s-1 with respect to total metal ions (Fe + Eu), which is about 3 times higher than that of Fe3O4 nanoparticles with similar size. Moreover, both r1 and r2 values of EuIO nanocubes can be tuned by varying their sizes and Eu doping ratios. After citrate coating, EuIO nanocubes can provide enhanced T1 and T2 contrast effects in small animals, particularly in the cardiac and liver regions. This work may provide an insightful strategy to design MRI contrast agents with both positive and negative contrast abilities for biomedical applications.Magnetic resonance imaging (MRI) contrast agents with both positive (T1) and negative (T2) contrast abilities are needed in clinical diagnosis for fault-free accurate detection of lesions. We report a facile synthesis of europium-engineered iron oxide (EuIO) nanocubes as T1 and T2 contrast agents for MRI in living subjects. The Eu(iii) oxide-embedded iron oxide nanoparticles significantly increase the T1 relaxivity with an enhanced positive contrast effect. EuIO nanocubes with 14 nm in diameter showed a high r1 value of 36.8 mM-1 s-1 with respect to total metal ions (Fe + Eu), which is about 3 times higher than that of Fe3O4 nanoparticles with similar size. Moreover, both r1 and r2 values of EuIO nanocubes can be tuned by varying their sizes and Eu doping ratios. After citrate coating, EuIO nanocubes can provide enhanced T1 and T2 contrast effects in small animals, particularly in the cardiac and liver

  17. Surface-NMR measurements of the longitudinal relaxation time T1 in a homogeneous sand aquifer in Skive, Denmark

    NASA Astrophysics Data System (ADS)

    Walbrecker, Jan O.; Behroozmand, Ahmad A.

    2012-12-01

    Surface nuclear magnetic resonance (surface NMR) is a geophysical technique used in the exploration of shallow aquifers. It is based on measuring the NMR response of water molecules to excitation by electromagnetic pulses. By increasing the moment of applied pulses, successively deeper regions of an aquifer can be probed. The longitudinal relaxation time T1, determined from the NMR experiment, depends on pore size and can be potentially used to estimate hydraulic conductivity. A novel scheme was recently proposed that was shown theoretically to be more reliable for acquiring surface-NMR T1 data than traditional acquisition. In this proof-of-concept study we provide the first empirical evidence for the superiority of the novel scheme. We chose a survey site close to Skive, Denmark, where proximate boreholes indicate a homogeneous sandy aquifer in the top 30 m. The homogeneous composition implies that the distribution of pore sizes does not vary significantly across the formation. Because pore size is reflected by the T1 relaxation time, we therefore assume that the homogeneous aquifer can be characterized by a single T1 independent of the applied pulse moment (i.e., sampled depth region)—this is the benchmark condition we tested with our surface-NMR measurements. We collected surface-NMR T1 data employing the traditional as well as the novel acquisition scheme at various pulse moments. For each pulse moment we infer a T1 relaxation time based on extensively sampled data (14 delay-time data points). The T1 relaxation times obtained using the novel scheme show a constant value of about 820 ms (± 38 ms) for all pulse moments. In contrast, the T1 relaxation times determined using the traditional scheme vary significantly between 530 and 750 ms with pulse moment, which in an inversion would result in a spatial variation of T1 across the aquifer. The results based on the novel scheme are consistent with a homogeneous aquifer, which we expect based on the borehole

  18. Proton-detected 3D 1H/13C/1H correlation experiment for structural analysis in rigid solids under ultrafast-MAS above 60 kHz

    NASA Astrophysics Data System (ADS)

    Zhang, Rongchun; Nishiyama, Yusuke; Ramamoorthy, Ayyalusamy

    2015-10-01

    A proton-detected 3D 1H/13C/1H chemical shift correlation experiment is proposed for the assignment of chemical shift resonances, identification of 13C-1H connectivities, and proximities of 13C-1H and 1H-1H nuclei under ultrafast magic-angle-spinning (ultrafast-MAS) conditions. Ultrafast-MAS is used to suppress all anisotropic interactions including 1H-1H dipolar couplings, while the finite-pulse radio frequency driven dipolar recoupling (fp-RFDR) pulse sequence is used to recouple dipolar couplings among protons and the insensitive nuclei enhanced by polarization transfer technique is used to transfer magnetization between heteronuclear spins. The 3D experiment eliminates signals from non-carbon-bonded protons and non-proton-bonded carbons to enhance spectral resolution. The 2D (F1/F3) 1H/1H and 2D 13C/1H (F2/F3) chemical shift correlation spectra extracted from the 3D spectrum enable the identification of 1H-1H proximity and 13C-1H connectivity. In addition, the 2D (F1/F2) 1H/13C chemical shift correlation spectrum, incorporated with proton magnetization exchange via the fp-RFDR recoupling of 1H-1H dipolar couplings, enables the measurement of proximities between 13C and even the remote non-carbon-bonded protons. The 3D experiment also gives three-spin proximities of 1H-1H-13C chains. Experimental results obtained from powder samples of L-alanine and L-histidine ṡ H2O ṡ HCl demonstrate the efficiency of the 3D experiment.

  19. T1r3 taste receptor involvement in gustatory neural responses to ethanol and oral ethanol preference

    PubMed Central

    Norman, Meghan B.; Lemon, Christian H.

    2010-01-01

    Elevated alcohol consumption is associated with enhanced preference for sweet substances across species and may be mediated by oral alcohol-induced activation of neurobiological substrates for sweet taste. Here, we directly examined the contribution of the T1r3 receptor protein, important for sweet taste detection in mammals, to ethanol intake and preference and the neural processing of ethanol taste by measuring behavioral and central neurophysiological responses to oral alcohol in T1r3 receptor-deficient mice and their C57BL/6J background strain. T1r3 knockout and wild-type mice were tested in behavioral preference assays for long-term voluntary intake of a broad concentration range of ethanol, sucrose, and quinine. For neurophysiological experiments, separate groups of mice of each genotype were anesthetized, and taste responses to ethanol and stimuli of different taste qualities were electrophysiologically recorded from gustatory neurons in the nucleus of the solitary tract. Mice lacking the T1r3 receptor were behaviorally indifferent to alcohol (i.e., ∼50% preference values) at concentrations typically preferred by wild-type mice (5–15%). Central neural taste responses to ethanol in T1r3-deficient mice were significantly lower compared with C57BL/6J controls, a strain for which oral ethanol stimulation produced a concentration-dependent activation of sweet-responsive NTS gustatory neurons. An attenuated difference in ethanol preference between knockouts and controls at concentrations >15% indicated that other sensory and/or postingestive effects of ethanol compete with sweet taste input at high concentrations. As expected, T1r3 knockouts exhibited strongly suppressed behavioral and neural taste responses to sweeteners but did not differ from wild-type mice in responses to prototypic salt, acid, or bitter stimuli. These data implicate the T1r3 receptor in the sensory detection and transduction of ethanol taste. PMID:20145204

  20. Investigation of Proton Dynamics in a (CH3)4 NCdCl3 Single Crystal by using 1H Nuclear Magnetic Resonance Measurements

    NASA Astrophysics Data System (ADS)

    Lee, Moohee; Sim, Jung Seok; Kang, Kihyeok; Hyoun Kim, Ho; Kim, Ae Ran

    2013-03-01

    (CH3)4 NCdCl3(TMCC) is reported to exhibit two first-order structural phase transitions. The crystal has a hexagonal structure in phase I at room temperature and then changes to a monoclinic one in phase II below 118 K. Finally a ferro-elastic monoclinic phase III appears below 104 K. The a- and c-axes of TMMC were found by using X-ray diffraction at room temperature. 1H NMR measurements of spectrum, spin-lattice relaxation time T1 and rotating-frame relaxation time T1ρ were performed at 4.8 T parallel or perpendicular to the c-axis from 300 K down to 65 K. The spectrum shows no significant changes at both transition temperatures. T1 and T1ρ monotonically decrease at low temperature and then show an abrupt decrease around 110 K. As the temperature decreases further, T1 shows a minimum at 100 K and becomes longer whereas T1ρ continuously decreases. From these data, the proton dynamical behavior is analyzed and identified.

  1. Proton-detected 3D 14N/14N/1H isotropic shift correlation experiment mediated through 1H-1H RFDR mixing on a natural abundant sample under ultrafast MAS

    NASA Astrophysics Data System (ADS)

    Pandey, Manoj Kumar; Nishiyama, Yusuke

    2015-09-01

    In this contribution, we have demonstrated a proton detection-based approach on a natural abundant powdered L-Histidine HCl-H2O sample at ultrafast magic angle spinning (MAS) to accomplish 14N/14N correlation from a 3D 14N/14N/1H isotropic shift correlation experiment mediated through 1H finite-pulse radio frequency-driven recoupling (fp-RFDR). Herein the heteronuclear magnetization transfer between 14N and 1H has been achieved by HMQC experiment, whereas 14N/14N correlation is attained through enhanced 1H-1H spin diffusion process due to 1H-1H dipolar recoupling during the RFDR mixing. While the use of ultrafast MAS (90 kHz) provides sensitivity enhancement through increased 1H transverse relaxation time (T2), the use of micro-coil probe which can withstand strong 14N radio frequency (RF) fields further improves the sensitivity per unit sample volume.

  2. Impact of uncertainty in longitudinal T1 measurements on quantification of dynamic contrast-enhanced MRI.

    PubMed

    Aryal, Madhava P; Chenevert, Thomas L; Cao, Yue

    2016-04-01

    The objective of this study was to assess the uncertainty in T1 measurement, by estimating the repeatability coefficient (RC) from two repeated scans, in normal appearing brain tissues employing two different T1 mapping methods. All brain MRI scans were performed on a 3 T MR scanner in 10 patients who had low grade/benign tumors and partial brain radiation therapy (RT) without chemotherapy, at pre-RT, 3 weeks into RT, end RT (6 weeks) and 11, 33, and 85 weeks after RT. T1-weighted images were acquired using (1) a spoiled gradient echo sequence with two flip angles (2FA: 5° and 15°) and (2) a progressive saturation recovery sequence (pSR) with five different TR values (100-2000 ms). Manually drawn volumes of interest (VOIs) included left and right normal putamen and thalamus in gray matter, and frontal and parietal white matter, which were distant from tumors and received a total of accumulated radiation doses less than 5 Gy at 3 weeks. No significant changes or even trends in mean T1 from pre-RT to 3 weeks into RT in these VOIs (p ≥ 0.11, Wilcoxon sign test) allowed us to calculate the repeatability statistics of between-subject means of squares, within-subject means of squares, F-score, and RC. The 2FA method produced RCs in the range of (9.7-11.7)% in gray matter and (12.2-14.5)% in white matter; while the pSR method led to RCs ranging from 10.9 to 17.9% in gray matter and 7.5 to 10.3% in white matter. The overall mean (±SD) RCs produced by the two methods, 12.0 (±1.6)% for 2FA and 12.0 (±3.8)% for pSR, were not significantly different (p = 0.97). A similar repeatability in T1 measurement produced by the time efficient 2FA method compared with the time consuming pSR method demonstrates that the 2FA method is desirable to integrate into dynamic contrast-enhanced MRI for rapid acquisition. PMID:27358934

  3. Exploring the 3-piperidin-4-yl-1H-indole scaffold as a novel antimalarial chemotype.

    PubMed

    Santos, Sofia A; Lukens, Amanda K; Coelho, Lis; Nogueira, Fátima; Wirth, Dyann F; Mazitschek, Ralph; Moreira, Rui; Paulo, Alexandra

    2015-09-18

    A series of 3-piperidin-4-yl-1H-indoles with building block diversity was synthesized based on a hit derived from an HTS whole-cell screen against Plasmodium falciparum. Thirty-eight compounds were obtained following a three-step synthetic approach and evaluated for anti-parasitic activity. The SAR shows that 3-piperidin-4-yl-1H-indole is intolerant to most N-piperidinyl modifications. Nevertheless, we were able to identify a new compound (10d) with lead-like properties (MW = 305; cLogP = 2.42), showing antimalarial activity against drug-resistant and sensitive strains (EC50 values ∼ 3 μM), selectivity for malaria parasite and no cross-resistance with chloroquine, thus representing a potential new chemotype for further optimization towards novel and affordable antimalarial drugs. PMID:26295174

  4. A mathematical force and moment model of a UH-1H helicopter for flight dynamics simulations

    NASA Technical Reports Server (NTRS)

    Talbot, P. D.; Corliss, L. D.

    1977-01-01

    A model of a UH-1H helicopter was developed to support flight simulations and for developmental work on an avionics system known as V/STOLAND system. Equations and numerical values of constants used to represent the helicopter are presented. Responses to stop inputs of the cyclic and collective controls are shown and compared with flight test data for a UH-1H. The model coefficients were adjusted in an attempt to get a consistant match with the flight time histories at hover and 60 knots. Response matching was obtained at 60 knots, but the matching at hover was not as successful. Pilot evaluations of the model, both fixed and moving base, were made.

  5. Controls on compound specific 2H/1H of leaf waxes along a North American monsoonal transect

    NASA Astrophysics Data System (ADS)

    Berke, M. A.; Tipple, B. J.; Hambach, B.; Ehleringer, J. R.

    2013-12-01

    The use of hydrogen isotope ratios of sedimentary n-alkanes from leaf waxes has become an important method for the reconstruction of paleohydrologic conditions. Ideally, the relationship between lipid 2H/1H values and source water is one-to-one. But the extent to which the 2H/1H values are altered between initial source water and lipid 2H/1H values varies by plant type and environment. Additionally, these variables may be confounded by use of varied source waters by plants in the same ecosystem. Here, we use a transect study across the arid southwestern landscape of the United States, which is heavily influenced by the North American Monsoon, to study the variability in 2H/1H values of leaf waxes in co-occurring plants from Tucson, Arizona to Salt Lake City, Utah. Perennials, including rabbit brush (Chrysothamnus nauseosus), sagebrush (Artemisia tridentata), and gambel oak (Quercus gambelii) and an annual plant, sunflower (Helianthus annuus), were chosen for their wide geographic distribution along the entire transect. Our results indicate that n-alkane distribution for each plant was similar and generally showed no relationship to environmental variables (elevation, mean annual precipitation, latitude, and temperature). However, we find evidence of n-alkane 2H/1H value relating to transect latitude, a relationship that is weaker for all samples combined than the strong individual correlation for each plant species. Further, these 2H/1H values suggest that not all plants in the monsoon region utilize monsoon-delivered precipitation. These results imply an adaptation to discontinuous spatial coverage and amount of monsoonal precipitation and suggest care must be taken when assuming consistent source water for different plants, particularly in regions with highly seasonal precipitation delivery.

  6. Hydrogen concentration dependence of 1H Knight shift in NbH x studied by 1H MAS NMR

    NASA Astrophysics Data System (ADS)

    Ueda, Takahiro; Hayashi, Shigenobu; Hayamizu, Kikuko

    1993-08-01

    Hydrogen concentration dependence of the Knight shift of protons in NbH x(0.05≤×≤1.05) has been studied by means of 1H MAS (magic angle sample spinning) NMR. In the mixed-phase samples of the α and β phases (0.05<×≤0.7), it is found that the 1H Knight shift of β-NbH x depends on the phase fraction. The shift variation in the β phase can be correlated with the unit cell volume, being explained by the variation of the density of electronic states at the Fermi level N(0) due to the compression of the crystal lattice. On the other hand, in the single β-phase samples (0.7<×≤1.05), the 1H Knight shift becomes smaller as the hydrogen concentration increases. This variation can be explained by increase in the number of electrons in the unit cell with the hydrogen concentration, resulting in the N(0) increase.

  7. Native T1-mapping detects the location, extent and patterns of acute myocarditis without the need for gadolinium contrast agents

    PubMed Central

    2014-01-01

    addition, T1-mapping offers significant incremental diagnostic value, detecting additional areas of myocardial involvement beyond T2W and LGE imaging and identified extra cases when these conventional methods failed to identify abnormalities. In the future, it may be possible to perform gadolinium-free CMR using cine and T1-mapping for tissue characterization and may be particularly useful for patients in whom gadolinium contrast is contraindicated. PMID:24886708

  8. Thermotropic ionic liquid crystals. II. 1H and 23Na NMR study of the smectic mesophase of molten sodium n-butyrate and sodium isovalerate

    NASA Astrophysics Data System (ADS)

    Bonekamp, J. E.; Eguchi, T.; Plesko, S.; Jonas, J.

    1983-08-01

    The 1H and 23Na NMR studies of smectic ionic mesophases of molten sodium n-butyrate and sodium isovalerate are reported over the temperature range of the stability of the liquid crystalline phases. The 1H spin-lattice relaxation times T1 at ν0=9.2, 24.3, and 60 MHz for the anions of both the systems are interpreted in terms of diffusion intermolecular relaxation mechanism. The predicted anion diffusion coefficients are in agreement with those measured directly by spin-echo technique and indicate that the anion diffuses rapidly. In contrast to the T1 relaxation mechanism the results obtained for the proton relaxation times in the rotating coordinate frame T1ρ indicate that the order-fluctuation relaxation mechanism determines the frequency dispersion of T1ρ. The analysis of the T1ρ data provides an approximate measure of the order parameter S as a function of temperature. Fourier transform spectra of the 23Na transitions show that the electric field gradient (EFG) at the Na+ ion is nonaveraged and of such a strength as to produce a second order quadrupole effect in the spectra of the central transition. From the first-order splitting, the quadrupole coupling constant (QCC) is obtained as a function of temperature. The gradual temperature change of QCC demonstrates that only a single liquid crystalline phase exists over the temperature interval of the stability of the smectic mesophase. Using approximate analysis the correlation time τc for the EFG fluctuation is obtained from the 23Na T1 data for the melts of both sodium n-butyrate and sodium isovalerate.

  9. Flowing Foam: T1 events and solid-liquid transitions.

    NASA Astrophysics Data System (ADS)

    Dennin, Michael

    2005-11-01

    Flowing aqueous foam is found in many applications ranging from oil recovery, to fire fighting, to spreading shaving cream. Aqueous foam consists of gas bubbles with liquid walls. One of the striking features of foam is that despite being composed entirely of fluids, its mechanical properties are either those of a solid (elastic response) or fluid (viscous flow), depending on the nature of the applied stress and strains. We study the transition between these two regimes using a model foam system: bubble rafts. Bubble rafts are a single layer of bubbles floating on the air-water surface. This allows us to track the motion of all the bubbles during flow. In this talk, we will present two main results. First, we will discuss the observation of the coexistence between a solid-like and fluid-like state during flow. Second, we will discuss the role played by nonlinear, topological rearrangements, known as T1 events, in determining the mechanical response of the system.

  10. Silibinin and Paclitaxel Cotreatment Significantly Suppress the Activity and Lung Metastasis of Triple Negative 4T1 Mammary Tumor Cell in Mice

    PubMed Central

    Ho, Bing-Ying; Lin, Chun-Hung; Apaya, Maria Karmella; Chao, Wen-Wan; Shyur, Lie-Fen

    2012-01-01

    The in vitro and in vivo bioactivities of silibinin (SB), paclitaxel (PTX) and SB and PTX in combination (SB+PTX) against murine metastatic mammary 4T1 cancer cell line were investigated. Isobologram and combination index (CI) analyses showed that SB and PTX can function synergistically in the inhibition of 4T1 cell proliferation with a CI value < 1. Both SB and PTX alone or SB+PTX treatment inhibited 4T1 cell migration and motility possibly through downregulation of the serpin protease nexin-1 (PN-1) and N-cadherin expression, inhibition of matrix metalloprotease (MMP)-9 activity, and upregulation of E-cadherin. Flow cytometry and Western blot analyses demonstrated that both drugs deregulated cell-cycle mediators and induced apoptosis in 4T1 cells. A real-time in vivo bioluminescence imaging system to monitor the breast cancer cell metastasis in syngeneic BALB/c mice was established using a stable 4T1pGL-COX-2/Luc cell clone carrying a COX-2 promoter driven-luciferase reporter gene. In vivo study using the allograft 4T1pGL-COX-2/Luc metastatic mouse model indicated that SB co-treated with PTX can significantly suppress lung metastasis of 4T1 cells likely through inhibiting cell proliferation and angiogenesis. Together, this study demonstrates that SB could act synergistically with PTX in 4T1 cells, providing a therapeutic option for highly metastatic triple negative breast cancer. PMID:24716145

  11. Complexation of oxygen ligands with dimeric rhodium(II) tetrakistrifluoroacetate in chloroform: 1H, 13C NMR and DFT studies

    NASA Astrophysics Data System (ADS)

    Głaszczka, Rafał; Jaźwiński, Jarosław

    2013-03-01

    The complexation of dimeric rhodium(II) tetrakistrifluoroacetylate with 25 ligands containing oxygen atoms: alcohols, ethers, ketones, aldehydes, carboxylic acids and esters in chloroform solution have been investigated by 1H and 13C NMR spectroscopy and Density Functional Theory (DFT) methods. Investigated ligands form 1:1 adducts in our experimental conditions, with stability constants in the order of several hundred mol-1. The exchange of ligands in solution is fast on the NMR spectroscopic timescale. The decrease of longitudinal relaxation times T1 in ligands in the presence of rhodium salt has been tested as the means of determination of the complexation site in ligands. The influence of complexation on chemical shifts in ligands was evaluated by a parameter complexation shift Δδ (Δδ = δadd - δlig). These parameters were positive (>0 ppm) and did not exceed 1 ppm for 1H NMR; and varied from ca. -5 to +15 ppm in the case of 13C NMR. The calculation by DFT methods using the B3LYP functional (structure optimization, electronic energy) and B3PW91 functional (shielding), and combinations of the (6-31G(2d), 6-311G++(2d,p), and LANL2DZ basis sets, followed by scaling procedures reproduced satisfactorily 1H and 13C chemical shifts and, with some limitations, allowed to estimate Δδ parameters.

  12. Dynamics-based selective 2D (1)H/(1)H chemical shift correlation spectroscopy under ultrafast MAS conditions.

    PubMed

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2015-05-28

    Dynamics plays important roles in determining the physical, chemical, and functional properties of a variety of chemical and biological materials. However, a material (such as a polymer) generally has mobile and rigid regions in order to have high strength and toughness at the same time. Therefore, it is difficult to measure the role of mobile phase without being affected by the rigid components. Herein, we propose a highly sensitive solid-state NMR approach that utilizes a dipolar-coupling based filter (composed of 12 equally spaced 90° RF pulses) to selectively measure the correlation of (1)H chemical shifts from the mobile regions of a material. It is interesting to find that the rotor-synchronized dipolar filter strength decreases with increasing inter-pulse delay between the 90° pulses, whereas the dipolar filter strength increases with increasing inter-pulse delay under static conditions. In this study, we also demonstrate the unique advantages of proton-detection under ultrafast magic-angle-spinning conditions to enhance the spectral resolution and sensitivity for studies on small molecules as well as multi-phase polymers. Our results further demonstrate the use of finite-pulse radio-frequency driven recoupling pulse sequence to efficiently recouple weak proton-proton dipolar couplings in the dynamic regions of a molecule and to facilitate the fast acquisition of (1)H/(1)H correlation spectrum compared to the traditional 2D NOESY (Nuclear Overhauser effect spectroscopy) experiment. We believe that the proposed approach is beneficial to study mobile components in multi-phase systems, such as block copolymers, polymer blends, nanocomposites, heterogeneous amyloid mixture of oligomers and fibers, and other materials. PMID:26026440

  13. Simultaneous T1 and T2 Brain Relaxometry in Asymptomatic Volunteers using Magnetic Resonance Fingerprinting

    PubMed Central

    Badve, Chaitra; Yu, Alice; Rogers, Matthew; Ma, Dan; Liu, Yiying; Schluchter, Mark; Sunshine, Jeffrey; Griswold, Mark; Gulani, Vikas

    2016-01-01

    Magnetic resonance fingerprinting (MRF) is a method of image acquisition that produces multiple MR parametric maps from a single scan. Here, we describe the normal range and progression of MRF-derived relaxometry values with age in healthy individuals. 56 normal volunteers (ages 11-71 years, M:F 24:32) were scanned. Regions of interest were drawn on T1 and T2 maps in 38 areas, including lobar and deep white matter, deep gray nuclei, thalami and posterior fossa structures. Relaxometry differences were assessed using a forward stepwise selection of a baseline model including either gender, age, or both, where variables were included if they contributed significantly (p<0.05). Additionally, differences in regional anatomy, including comparisons between hemispheres and between anatomical subcomponents, were assessed by paired t-tests. Using this protocol, MRF-derived T1 and T2 in frontal WM regions were found to increase in with age, while occipital and temporal regions remained relatively stable. Deep gray nuclei, including substantia nigra, were found to have age-related decreases in relaxometry. Gender differences were observed in T1 and T2 of temporal regions, cerebellum and pons. Males were also found to have more rapid age-related changes in frontal and parietal WM. Regional differences were identified between hemispheres, between genu and splenium of corpus callosum, and between posteromedial and anterolateral thalami. In conclusion, MRF quantification can measure relaxometry trends in healthy individuals that are in agreement with current understanding of neuroanatomy and neurobiology, and has the ability to uncover additional patterns that have not yet been explored. PMID:26824078

  14. Retrieving atmospheric temperature parameters from DMSP SSM/T-1 data with a neural network

    NASA Astrophysics Data System (ADS)

    Butler, Charles T.; Meredith, R. v. Z.; Stogryn, A. P.

    1996-03-01

    We show that back propagation neural networks yield excellent results in retrieving air temperature profiles from the 1000- to the 10-mbar pressure level together with tropopause temperature and pressure estimates using operational brightness temperature data from the special sensor microwave imager (SSM/T-1) microwave radiometer. Networks trained and tested with matched SSM/T-1 measurements and conventional soundings collected during a 30-day period in northern hemisphere winter demonstrated rms retrieval errors substantially less than 2K from 500 to 30 mbar, significantly outperforming an operational linear-regression algorithm using the same data. Tropopause temperature and pressure retrievals showed rms errors of 2.15 K and 19.8 mbar. Retrieval accuracy of the system exceeds that of any previously published method using DMSP data and equals or exceeds that of published studies using data from other satellite-borne instruments. Retrieval accuracy under possible failure modes of the SSM/T-1 instrument are also considered, as are ways to recover from single-channel loss. The method retrieves profiles and tropopause parameters with acceptable accuracy either if the brightness-temperature of any one channel is offset 1.5 K or more or if uniform random noise with a peak value in the range (-2, 2) K is added in one channel. The performance is only slightly more impaired if all channels are simultaneously offset up to 1.5 K or if random noise in the range (-1, 1) K is simultaneously added to all channels. Under single-channel loss the retrieval error can be made small at virtually every level by retrieving with a network trained without that channel.

  15. Europium-engineered iron oxide nanocubes with high T1 and T2 contrast abilities for MRI in living subjects.

    PubMed

    Yang, Lijiao; Zhou, Zijian; Liu, Hanyu; Wu, Changqiang; Zhang, Hui; Huang, Guoming; Ai, Hua; Gao, Jinhao

    2015-04-21

    Magnetic resonance imaging (MRI) contrast agents with both positive (T1) and negative (T2) contrast abilities are needed in clinical diagnosis for fault-free accurate detection of lesions. We report a facile synthesis of europium-engineered iron oxide (EuIO) nanocubes as T1 and T2 contrast agents for MRI in living subjects. The Eu(iii) oxide-embedded iron oxide nanoparticles significantly increase the T1 relaxivity with an enhanced positive contrast effect. EuIO nanocubes with 14 nm in diameter showed a high r1 value of 36.8 mM(-1) s(-1) with respect to total metal ions (Fe + Eu), which is about 3 times higher than that of Fe3O4 nanoparticles with similar size. Moreover, both r1 and r2 values of EuIO nanocubes can be tuned by varying their sizes and Eu doping ratios. After citrate coating, EuIO nanocubes can provide enhanced T1 and T2 contrast effects in small animals, particularly in the cardiac and liver regions. This work may provide an insightful strategy to design MRI contrast agents with both positive and negative contrast abilities for biomedical applications. PMID:25806860

  16. The use of IRMS, (1)H NMR and chemical analysis to characterise Italian and imported Tunisian olive oils.

    PubMed

    Camin, Federica; Pavone, Anita; Bontempo, Luana; Wehrens, Ron; Paolini, Mauro; Faberi, Angelo; Marianella, Rosa Maria; Capitani, Donatella; Vista, Silvia; Mannina, Luisa

    2016-04-01

    Isotope Ratio Mass Spectrometry (IRMS), (1)H Nuclear Magnetic Resonance ((1)H NMR), conventional chemical analysis and chemometric elaboration were used to assess quality and to define and confirm the geographical origin of 177 Italian PDO (Protected Denomination of Origin) olive oils and 86 samples imported from Tunisia. Italian olive oils were richer in squalene and unsaturated fatty acids, whereas Tunisian olive oils showed higher δ(18)O, δ(2)H, linoleic acid, saturated fatty acids β-sitosterol, sn-1 and 3 diglyceride values. Furthermore, all the Tunisian samples imported were of poor quality, with a K232 and/or acidity values above the limits established for extra virgin olive oils. By combining isotopic composition with (1)H NMR data using a multivariate statistical approach, a statistical model able to discriminate olive oil from Italy and those imported from Tunisia was obtained, with an optimal differentiation ability arriving at around 98%. PMID:26593470

  17. Comparison of Trifecta and Pentafecta Outcomes between T1a and T1b Renal Masses following Robot-Assisted Partial Nephrectomy (RAPN) with Minimum One Year Follow Up: Can RAPN for T1b Renal Masses Be Feasible?

    PubMed Central

    Kim, Dae Keun; Kim, Lawrence H. C.; Raheem, Ali Abdel; Shin, Tae Young; Alabdulaali, Ibrahim; Yoon, Young Eun; Han, Woong Kyu; Rha, Koon Ho

    2016-01-01

    Purpose/Objectives To investigate the feasibility of RAPN on T1b renal mass by assessment of Trifecta and Pentafecta rate between T1a and T1b renal mass. Materials/Methods We retrospectively reviewed the medical records of 277 cases of RPN performed from 2006 to 2015. Sixty patients with clinically T1b renal masses (> 4cm and ≤ 7 cm) were identified, and from 180 patients with clinically T1a renal mass, 60 patients were matched with T1b renal mass by propensity score. Tumor complexity was investigated according to R.E.N.A.L nephrometry score. “Pentafecta” was defined as achievement of Trifecta (negative surgical margin, no postoperative complications and warm ischemia time of ≤ 25 minutes) with addition of over 90% estimated GFR preservation and no chronic kidney disease stage upgrading at 1 year postoperative period. Propensity score matching was performed by OneToManyMTCH. Logistic regression models were used to identify the variables which predict the Trifecta, and Pentafecta ac. Results Preoperative variables (age, sex, body mass index, ASA score) were similar between T1a and T1b after propensity score matching. The median R.E.N.A.L. nephrometry score was 8 vs 9 for T1a and T1b respectively (p<0.001). The median warm ischemia time was 20.1 min vs 26.2 min (p<0.001). Positive surgical margin rate was 5% vs 6.6% (p = 0.729) and overall complication rate of 13.3%. vs 15% (p = 0.793). The rate of achievement of Trifecta rate were 65.3% vs 43.3% (p = 0.017) and Pentafecta rate were 38.3% vs 26.7% (p = 0.172). For achievement of Pentafecta, R.E.N.A.L nephrometry score (HR 0.80; 95% CI (0.67–0.97); p = 0.031) was significant predictor of achieving Pentafecta. Subanalyis to assess the component of R.E.N.A.L nephrometry score, L component (location relative to the polar lines, HR 0.63; 95% CI (0.38–1.03); P = 0.064) was relatively important component for Pentafecta achievement. Conclusions The rate of Pentafecta after RAPN was comparable between T1a and T1b

  18. Core/shell Fe3O4/Gd2O3 nanocubes as T1-T2 dual modal MRI contrast agents.

    PubMed

    Li, Fenfen; Zhi, Debo; Luo, Yufeng; Zhang, Jiqian; Nan, Xiang; Zhang, Yunjiao; Zhou, Wei; Qiu, Bensheng; Wen, Longping; Liang, Gaolin

    2016-07-01

    T1-T2 dual modal magnetic resonance imaging (MRI) has attracted considerable interest because it offers complementary diagnostic information, leading to more precise diagnosis. To date, a number of nanostructures have been reported as T1-T2 dual modal MR contrast agents (CAs). However, hybrids of nanocubes with both iron and gadolinium (Gd) elements as T1-T2 dual modal CAs have not been reported. Herein, we report the synthesis of novel core/shell Fe3O4/Gd2O3 nanocubes as T1-T2 dual-modal CAs and their application for enhanced T1-T2 MR imaging of rat livers. A relaxivity study at 1.5 T indicated that our Fe3O4/Gd2O3 nanocubes have an r1 value of 45.24 mM(-1) s(-1) and an r2 value of 186.51 mM(-1) s(-1), which were about two folds of those of Gd2O3 nanoparticles and Fe3O4 nanocubes, respectively. In vivo MR imaging of rats showed both T1-positive and T2-negative contrast enhancements in the livers. We envision that our Fe3O4/Gd2O3 nanocubes could be applied as T1-T2 dual modal MR CAs for a wide range of theranostic applications in the near future. PMID:27297334

  19. Sensing of amino acids by the gut-expressed taste receptor T1R1-T1R3 stimulates CCK secretion.

    PubMed

    Daly, Kristian; Al-Rammahi, Miran; Moran, Andrew; Marcello, Marco; Ninomiya, Yuzo; Shirazi-Beechey, Soraya P

    2013-02-01

    CCK is secreted by endocrine cells of the proximal intestine in response to dietary components, including amino acids. CCK plays a variety of roles in digestive processes, including inhibition of food intake, consistent with a role in satiety. In the lingual epithelium, the sensing of a broad spectrum of L-amino acids is accomplished by the heteromeric amino acid (umami) taste receptor (T1R1-T1R3). T1R1 and T1R3 subunits are also expressed in the intestine. A defining characteristic of umami sensing by T1R1-T1R3 is its potentiation by IMP or GMP. Furthermore, T1R1-T1R3 is not activated by Trp. We show here that, in response to L-amino acids (Phe, Leu, Glu, and Trp), but not D-amino acids, STC-1 enteroendocrine cells and mouse proximal small intestinal tissue explants secrete CCK and that IMP enhances Phe-, Leu-, and Glu-induced, but not Trp-induced, CCK secretion. Furthermore, small interfering RNA inhibition of T1R1 expression in STC-1 cells results in significant diminution of Phe-, Leu-, and Glu-stimulated, but not Trp-stimulated, CCK release. In STC-1 cells and mouse intestine, gurmarin inhibits Phe-, Leu-, and Glu-induced, but not Trp-stimulated, CCK secretion. In contrast, the Ca(2+)-sensing receptor antagonist NPS2143 inhibits Phe-stimulated CCK release partially and Trp-induced CCK secretion totally in mouse intestine. However, NPS2143 has no effect on Leu- or Glu-induced CCK secretion. Collectively, our data demonstrate that functional characteristics and cellular location of the gut-expressed T1R1-T1R3 support its role as a luminal sensor for Phe-, Leu-, and Glu-induced CCK secretion. PMID:23203156

  20. Activation of the umami taste receptor (T1R1/T1R3) initiates the peristaltic reflex and pellet propulsion in the distal colon

    PubMed Central

    Kendig, Derek M.; Hurst, Norman R.; Bradley, Zachary L.; Mahavadi, Sunila; Kuemmerle, John F.; Lyall, Vijay; DeSimone, John; Murthy, Karnam S.

    2014-01-01

    Intraluminal nutrients in the gut affect the peristaltic reflex, although the mechanism is not well defined. Recent evidence supports the presence of taste receptors and their signaling components in enteroendocrine cells, although their function is unclear. This study aimed to determine if nutrients modify colonic motility through activation of taste receptors. Colonic sections were immunostained for the umami taste receptor T1R1/T1R3, which mediates the response to umami ligands, such as monosodium glutamate (MSG), in taste cells. Ascending contraction, descending relaxation, and calcitonin gene-related peptide release were measured in three-chamber flat-sheet preparations of rat colon in response to MSG alone or with inosine 5′-monophosphate (IMP). Velocity of artificial fecal pellet propulsion was measured by video recording in guinea pig distal colon. T1R1/T1R3 receptors were present in enteroendocrine cells of colonic sections from human, rat, mouse, and guinea pig. MSG initiated ascending contraction and descending relaxation components of the peristaltic reflex and calcitonin gene-related peptide release in flat-sheet preparations. IMP augmented the MSG-induced effects, suggesting activation of T1R1/T1R3 receptors. In T1R1−/− mice, mucosal stroking, but not MSG, elicited a peristaltic reflex. Intraluminal perfusion of MSG enhanced the velocity of artificial fecal pellet propulsion, which was also augmented by IMP. Propulsion was also increased by l-cysteine, but not l-tryptophan, supporting a role of T1R1/T1R3 receptors. We conclude that T1R1/T1R3 activation by luminal MSG or l-cysteine elicits a peristaltic reflex and CGRP release and increases the velocity of pellet propulsion in distal colon. This mechanism may explain how nutrients regulate colonic propulsion. PMID:25324508

  1. Activation of the umami taste receptor (T1R1/T1R3) initiates the peristaltic reflex and pellet propulsion in the distal colon.

    PubMed

    Kendig, Derek M; Hurst, Norman R; Bradley, Zachary L; Mahavadi, Sunila; Kuemmerle, John F; Lyall, Vijay; DeSimone, John; Murthy, Karnam S; Grider, John R

    2014-12-01

    Intraluminal nutrients in the gut affect the peristaltic reflex, although the mechanism is not well defined. Recent evidence supports the presence of taste receptors and their signaling components in enteroendocrine cells, although their function is unclear. This study aimed to determine if nutrients modify colonic motility through activation of taste receptors. Colonic sections were immunostained for the umami taste receptor T1R1/T1R3, which mediates the response to umami ligands, such as monosodium glutamate (MSG), in taste cells. Ascending contraction, descending relaxation, and calcitonin gene-related peptide release were measured in three-chamber flat-sheet preparations of rat colon in response to MSG alone or with inosine 5'-monophosphate (IMP). Velocity of artificial fecal pellet propulsion was measured by video recording in guinea pig distal colon. T1R1/T1R3 receptors were present in enteroendocrine cells of colonic sections from human, rat, mouse, and guinea pig. MSG initiated ascending contraction and descending relaxation components of the peristaltic reflex and calcitonin gene-related peptide release in flat-sheet preparations. IMP augmented the MSG-induced effects, suggesting activation of T1R1/T1R3 receptors. In T1R1(-/-) mice, mucosal stroking, but not MSG, elicited a peristaltic reflex. Intraluminal perfusion of MSG enhanced the velocity of artificial fecal pellet propulsion, which was also augmented by IMP. Propulsion was also increased by l-cysteine, but not l-tryptophan, supporting a role of T1R1/T1R3 receptors. We conclude that T1R1/T1R3 activation by luminal MSG or l-cysteine elicits a peristaltic reflex and CGRP release and increases the velocity of pellet propulsion in distal colon. This mechanism may explain how nutrients regulate colonic propulsion. PMID:25324508

  2. T1 Relaxation Rate (R1) Indicates Nonlinear Mn Accumulation in Brain Tissue of Welders With Low-Level Exposure.

    PubMed

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

    2015-08-01

    Although the essential element manganese (Mn) is neurotoxic at high doses, the effects of lower exposure are unclear. MRI T1-weighted (TIW) imaging has been used to estimate brain Mn exposure via the pallidal index (PI), defined as the T1W intensity ratio in the globus pallidus (GP) versus frontal white matter (FWM). PI may not, however, be sensitive to Mn in GP because Mn also may accumulate in FWM. This study explored: (1) whether T1 relaxation rate (R1) could quantify brain Mn accumulation more sensitively; and (2) the dose-response relationship between estimated Mn exposure and T1 relaxation rate (R1). Thirty-five active welders and 30 controls were studied. Occupational questionnaires were used to estimate hours welding in the past 90 days (HrsW) and lifetime measures of Mn exposure. T1W imaging and T1-measurement were utilized to generate PI and R1 values in brain regions of interest (ROIs). PI did not show a significant association with any measure of Mn and/or welding-related exposure. Conversely, in several ROIs, R1 showed a nonlinear relationship to HrsW, with R1 signal increasing only after a critical exposure was reached. The GP had the greatest rate of Mn accumulation. Welders with higher exposure showed significantly higher R1 compared either with controls or with welders with lower exposure. Our data are additional evidence that Mn accumulation can be assessed more sensitively by R1 than by PI. Moreover, the nonlinear relationship between welding exposure and Mn brain accumulation should be considered in future studies and policies. PMID:25953701

  3. T1 Relaxation Rate (R1) Indicates Nonlinear Mn Accumulation in Brain Tissue of Welders With Low-Level Exposure

    PubMed Central

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

    2015-01-01

    Although the essential element manganese (Mn) is neurotoxic at high doses, the effects of lower exposure are unclear. MRI T1-weighted (TIW) imaging has been used to estimate brain Mn exposure via the pallidal index (PI), defined as the T1W intensity ratio in the globus pallidus (GP) versus frontal white matter (FWM). PI may not, however, be sensitive to Mn in GP because Mn also may accumulate in FWM. This study explored: (1) whether T1 relaxation rate (R1) could quantify brain Mn accumulation more sensitively; and (2) the dose-response relationship between estimated Mn exposure and T1 relaxation rate (R1). Thirty-five active welders and 30 controls were studied. Occupational questionnaires were used to estimate hours welding in the past 90 days (HrsW) and lifetime measures of Mn exposure. T1W imaging and T1-measurement were utilized to generate PI and R1 values in brain regions of interest (ROIs). PI did not show a significant association with any measure of Mn and/or welding-related exposure. Conversely, in several ROIs, R1 showed a nonlinear relationship to HrsW, with R1 signal increasing only after a critical exposure was reached. The GP had the greatest rate of Mn accumulation. Welders with higher exposure showed significantly higher R1 compared either with controls or with welders with lower exposure. Our data are additional evidence that Mn accumulation can be assessed more sensitively by R1 than by PI. Moreover, the nonlinear relationship between welding exposure and Mn brain accumulation should be considered in future studies and policies. PMID:25953701

  4. Hydrophobization of epoxy nanocomposite surface with 1H,1H,2H,2H-perfluorooctyltrichlorosilane for superhydrophobic properties

    NASA Astrophysics Data System (ADS)

    Psarski, Maciej; Marczak, Jacek; Celichowski, Grzegorz; Sobieraj, Grzegorz B.; Gumowski, Konrad; Zhou, Feng; Liu, Weimin

    2012-10-01

    Nature inspires the design of synthetic materials with superhydrophobic properties, which can be used for applications ranging from self-cleaning surfaces to microfluidic devices. Their water repellent properties are due to hierarchical (micrometer- and nanometre-scale) surface morphological structures, either made of hydrophobic substances or hydrophobized by appropriate surface treatment. In this work, the efficiency of two surface treatment procedures, with a hydrophobic fluoropolymer, synthesized and deposited from 1H,1H,2H,2H-perfluorooctyltrichlorosilane (PFOTS) is investigated. The procedures involved reactions from the gas and liquid phases of the PFOTS/hexane solutions. The hierarchical structure is created in an epoxy nanocomposite surface, by filling the resin with alumina nanoparticles and micron-sized glass beads and subsequent sandblasting with corundum microparticles. The chemical structure of the deposited fluoropolymer was examined using XPS spectroscopy. The topography of the modified surfaces was characterized using scanning electron microscopy (SEM), and atomic force microscopy (AFM). The hydrophobic properties of the modified surfaces were investigated by water contact and sliding angles measurements. The surfaces exhibited water contact angles of above 150° for both modification procedures, however only the gas phase modification provided the non-sticking behaviour of water droplets (sliding angle of 3°). The discrepancy is attributed to extra surface roughness provided by the latter procedure.

  5. Determination of relative orientation between (1)H CSA tensors from a 3D solid-state NMR experiment mediated through (1)H/(1)H RFDR mixing under ultrafast MAS.

    PubMed

    Pandey, Manoj Kumar; Nishiyama, Yusuke

    2015-09-01

    To obtain piercing insights into inter and intramolecular H-bonding, and π-electron interactions measurement of (1)H chemical shift anisotropy (CSA) tensors is gradually becoming an obvious choice. While the magnitude of CSA tensors provides unique information about the local electronic environment surrounding the nucleus, the relative orientation between these tensors can offer further insights into the spatial arrangement of interacting nuclei in their respective three-dimensional (3D) space. In this regard, we present a 3D anisotropic/anisotropic/isotropic proton chemical shift (CSA/CSA/CS) correlation experiment mediated through (1)H/(1)H radio frequency-driven recoupling (RFDR) which enhances spin diffusion through recoupled (1)H-(1)H dipolar couplings under ultrafast magic angle spinning (MAS) frequency (70kHz). Relative orientation between two interacting 1H CSA tensors is obtained by fitting two-interacting (1)H CSA tensors by fitting two-dimensional (2D) (1)H/(1)H CSA/CSA spectral slices through extensive numerical simulations. To recouple (1)H CSAs in the indirect frequency dimensions of a 3D experiment we have employed γ-encoded radio frequency (RF) pulse sequence based on R-symmetry (R188(7)) with a series of phase-alternated 2700(°)-90180(°) composite-180° pulses on citric acid sample. Due to robustness of applied (1)H CSA recoupling sequence towards the presence of RF field inhomogeneity, we have successfully achieved an excellent (1)H/(1)H CSA/CSA cross-correlation efficiency between H-bonded sites of citric acid. PMID:26065628

  6. 1H NMR investigation of self-association of vanillin in aqueous solution

    NASA Astrophysics Data System (ADS)

    Bogdan, Mircea; Floare, Calin G.; Pîrnau, Adrian

    2009-08-01

    A self-association of vanillin have been studied by 1H NMR spectroscopy using the analysis of proton chemical shifts changes in aqueous solution as a function of concentration. The experimental results have been analysed using indefinite non-cooperative and cooperative models of molecular self-association, enabling the determination of equilibrium constants, parameters of cooperativity and the limiting values of vanillin proton chemical shifts in the complex. It was found that the dimer formation creates energetically favourable conditions for subsequent molecular association.

  7. A possible detection of Jupiter's northern auroral S1(1) H2 quadrupole line emission

    NASA Technical Reports Server (NTRS)

    Trafton, L.; Carr, J.; Lester, D.; Harvey, P.

    1988-01-01

    An upper limit is presently determined for the mean intensity of the Jupiter northern Auroral UV/thermal hot spot's S1(1) H2 quadrupole emission, over an 8 sq arcsec illuminated beam; the value obtained is 4.2 X 10 to the -6th W/sq m per sr. It is suggested that the nonradiative deexitation of the H2 molecules via collisions with H may have been underestimated by Kim and Maguire (1986), due to uncertainties concerning auroral H density.

  8. Normal variation of magnetic resonance T1 relaxation times in the human population at 1.5 T using ShMOLLI

    PubMed Central

    2013-01-01

    Background Quantitative T1-mapping is rapidly becoming a clinical tool in cardiovascular magnetic resonance (CMR) to objectively distinguish normal from diseased myocardium. The usefulness of any quantitative technique to identify disease lies in its ability to detect significant differences from an established range of normal values. We aimed to assess the variability of myocardial T1 relaxation times in the normal human population estimated with recently proposed Shortened Modified Look-Locker Inversion recovery (ShMOLLI) T1 mapping technique. Methods A large cohort of healthy volunteers (n = 342, 50% females, age 11–69 years) from 3 clinical centres across two countries underwent CMR at 1.5T. Each examination provided a single average myocardial ShMOLLI T1 estimate using manually drawn myocardial contours on typically 3 short axis slices (average 3.4 ± 1.4), taking care not to include any blood pool in the myocardial contours. We established the normal reference range of myocardial and blood T1 values, and assessed the effect of potential confounding factors, including artefacts, partial volume, repeated measurements, age, gender, body size, hematocrit and heart rate. Results Native myocardial ShMOLLI T1 was 962 ± 25 ms. We identify the partial volume as primary source of potential error in the analysis of respective T1 maps and use 1 pixel erosion to represent “midwall myocardial” T1, resulting in a 0.9% decrease to 953 ± 23 ms. Midwall myocardial ShMOLLI T1 was reproducible with an intra-individual, intra- and inter-scanner variability of ≤2%. The principle biological parameter influencing myocardial ShMOLLI T1 was the female gender, with female T1 longer by 24 ms up to the age of 45 years, after which there was no significant difference from males. After correction for age and gender dependencies, heart rate was the only other physiologic factor with a small effect on myocardial ShMOLLI T1 (6ms/10bpm). Left and right ventricular

  9. One dimensional 1H, 2H and 3H

    NASA Astrophysics Data System (ADS)

    Vidal, A. J.; Astrakharchik, G. E.; Vranješ Markić, L.; Boronat, J.

    2016-05-01

    The ground-state properties of one-dimensional electron-spin-polarized hydrogen 1H, deuterium 2H, and tritium 3H are obtained by means of quantum Monte Carlo methods. The equations of state of the three isotopes are calculated for a wide range of linear densities. The pair correlation function and the static structure factor are obtained and interpreted within the framework of the Luttinger liquid theory. We report the density dependence of the Luttinger parameter and use it to identify different physical regimes: Bogoliubov Bose gas, super-Tonks–Girardeau gas, and quasi-crystal regimes for bosons; repulsive, attractive Fermi gas, and quasi-crystal regimes for fermions. We find that the tritium isotope is the one with the richest behavior. Our results show unambiguously the relevant role of the isotope mass in the properties of this quantum system.

  10. Decoding of exon splicing patterns in the human RUNX1-RUNX1T1 fusion gene.

    PubMed

    Grinev, Vasily V; Migas, Alexandr A; Kirsanava, Aksana D; Mishkova, Olga A; Siomava, Natalia; Ramanouskaya, Tatiana V; Vaitsiankova, Alina V; Ilyushonak, Ilia M; Nazarov, Petr V; Vallar, Laurent; Aleinikova, Olga V

    2015-11-01

    The t(8;21) translocation is the most widespread genetic defect found in human acute myeloid leukemia. This translocation results in the RUNX1-RUNX1T1 fusion gene that produces a wide variety of alternative transcripts and influences the course of the disease. The rules of combinatorics and splicing of exons in the RUNX1-RUNX1T1 transcripts are not known. To address this issue, we developed an exon graph model of the fusion gene organization and evaluated its local exon combinatorics by the exon combinatorial index (ECI). Here we show that the local exon combinatorics of the RUNX1-RUNX1T1 gene follows a power-law behavior and (i) the vast majority of exons has a low ECI, (ii) only a small part is represented by "exons-hubs" of splicing with very high ECI values, and (iii) it is scale-free and very sensitive to targeted skipping of "exons-hubs". Stochasticity of the splicing machinery and preferred usage of exons in alternative splicing can explain such behavior of the system. Stochasticity may explain up to 12% of the ECI variance and results in a number of non-coding and unproductive transcripts that can be considered as a noise. Half-life of these transcripts is increased due to the deregulation of some key genes of the nonsense-mediated decay system in leukemia cells. On the other hand, preferred usage of exons may explain up to 75% of the ECI variability. Our analysis revealed a set of splicing-related cis-regulatory motifs that can explain "attractiveness" of exons in alternative splicing but only when they are considered together. Cis-regulatory motifs are guides for splicing trans-factors and we observed a leukemia-specific profile of expression of the splicing genes in t(8;21)-positive blasts. Altogether, our results show that alternative splicing of the RUNX1-RUNX1T1 transcripts follows strict rules and that the power-law component of the fusion gene organization confers a high flexibility to this process. PMID:26320575

  11. Taste information derived from T1R-expressing taste cells in mice.

    PubMed

    Yoshida, Ryusuke; Ninomiya, Yuzo

    2016-03-01

    The taste system of animals is used to detect valuable nutrients and harmful compounds in foods. In humans and mice, sweet, bitter, salty, sour and umami tastes are considered the five basic taste qualities. Sweet and umami tastes are mediated by G-protein-coupled receptors, belonging to the T1R (taste receptor type 1) family. This family consists of three members (T1R1, T1R2 and T1R3). They function as sweet or umami taste receptors by forming heterodimeric complexes, T1R1+T1R3 (umami) or T1R2+T1R3 (sweet). Receptors for each of the basic tastes are thought to be expressed exclusively in taste bud cells. Sweet (T1R2+T1R3-expressing) taste cells were thought to be segregated from umami (T1R1+T1R3-expressing) taste cells in taste buds. However, recent studies have revealed that a significant portion of taste cells in mice expressed all T1R subunits and responded to both sweet and umami compounds. This suggests that sweet and umami taste cells may not be segregated. Mice are able to discriminate between sweet and umami tastes, and both tastes contribute to behavioural preferences for sweet or umami compounds. There is growing evidence that T1R3 is also involved in behavioural avoidance of calcium tastes in mice, which implies that there may be a further population of T1R-expressing taste cells that mediate aversion to calcium taste. Therefore the simple view of detection and segregation of sweet and umami tastes by T1R-expressing taste cells, in mice, is now open to re-examination. PMID:26912569

  12. Constant time INEPT CT-HSQC (CTi-CT-HSQC) - A new NMR method to measure accurate one-bond J and RDCs with strong 1H-1H couplings in natural abundance

    NASA Astrophysics Data System (ADS)

    Yu, Bingwu; van Ingen, Hugo; Freedberg, Darón I.

    2013-03-01

    Strong 1H-1H coupling can significantly reduce the accuracy of 1JCH measured from frequency differences in coupled HSQC spectra. Although accurate 1JCH values can be extracted from spectral simulation, it would be more convenient if the same accurate 1JCH values can be obtained experimentally. Furthermore, simulations reach their limit for residual dipolar coupling (RDC) measurement, as many significant, but immeasurable RDCs are introduced into the spin system when a molecule is weakly aligned, thus it is impossible to have a model spin system that truly represents the real spin system. Here we report a new J modulated method, constant-time INEPT CT-HSQC (CTi-CT-HSQC), to accurately measure one-bond scalar coupling constant and RDCs without strong coupling interference. In this method, changing the spacing between the two 180° pulses during a constant time INEPT period selectively modulates heteronuclear coupling in quantitative J fashion. Since the INEPT delays for measuring one-bond carbon-proton spectra are short compared to 3JHH, evolution due to (strong) 1H-1H coupling is marginal. The resulting curve shape is practically independent of 1H-1H coupling and only correlated to the heteronuclear coupling evolution. Consequently, an accurate 1JCH can be measured even in the presence of strong coupling. We tested this method on N-acetyl-glucosamine and mannose whose apparent isotropic 1JCH values are significantly affected by strong coupling with other methods. Agreement to within 0.5 Hz or better is found between 1JCH measured by this method and previously published simulation data. We further examined the strong coupling effects on RDC measurements and observed an error up to 100% for one bond RDCs using coupled HSQC in carbohydrates. We demonstrate that RDCs can be obtained with higher accuracy by CTi-CT-HSQC, which compensates the limitation of simulation method.

  13. Physical Properties and Chemical Composition of Aerosols sampled in T1 site during MILAGRO Campaign

    NASA Astrophysics Data System (ADS)

    Castro, T.; Mamani-Paco, R.; Saavedra, M. I.; Garcia, J.; Amador, O.; Carabali, G.; Salcido, A.; Herrera, E.; Baez, A.

    2007-05-01

    Results from pollutant measurements and meteorological variables corresponding to the month of March of 2006 during the MILAGRO campaign at site T1 are presented (Tecamac, State of Mexico). Three 8-stage cascade impactors (MOUDI) were employed to obtain aerosol samples of different sizes. For organic species analysis, samples were collected with a PM2.5 High Volume sampler. Mass and chemical composition (inorganic and organic species) were obtained with the use of analytical techniques. Particle morphology analysis was done with a TEM-EDAX System. Physical properties of aerosols were measured with a PSAP, a nephelometer and a CPC. According with area meteorology, days with Mexico City urban influence on T1 (March 9-12) and without influence (March 14 and 15) were analyzed. The particle average concentration during the whole campaign was 20,000 particles/cm3. For the days with and without urban influence the average concentrations were 17,500 and 8,000 particles/cm3 respectively. From the MOUDI data the highest particle concentration through the campaign was during the morning in the mode d50=0.32 μm. On the other hand, the cumulative highest concentration of all the stages was observed for March 19 followed by March 9. Scattering and absorption coefficients average obtained on T1 were 5.1x10-5 m-1 and 2.54x10-5 m-1 respectively and single scattering albedo was 0.676. These values show T1 as a polluted atmosphere, just as happens with megacities. Morphology of particles captured in a MOUDI impactor was studied. Particles between d50=0.18 μm and d50=1.8 μm sampled in T1 associated with urban influence (March 9) tended to show less irregular shapes through different periods of that day. These findings suggest the presence of large numbers of secondary aerosols and aged agglomerated particles. Particles ranging from d50=0.18 μm to d50=1.8 μm sampled in T1 and associated mainly with surrounding areas influence, e.g. Tizayuca Industrial Park (March 15) showed

  14. Interactions between Equine Cyclin T1, Tat, and TAR Are Disrupted by a Leucine-to-Valine Substitution Found in Human Cyclin T1

    PubMed Central

    Taube, Ran; Fujinaga, Koh; Irwin, Dan; Wimmer, Jörg; Geyer, Matthias; Peterlin, B. Matija

    2000-01-01

    Transcriptional transactivators (Tat) from human immunodeficiency and equine infectious anemia viruses (HIV and EIAV) interact with their transactivation response elements (TAR) to increase the rates of viral transcription. Whereas the human cyclin T1 is required for the binding of Tat to TAR from HIV, it is unknown how Tat from EIAV interacts with its TAR. Furthermore, Tat from EIAV functions in equine and canine cells but not in human cells. In this study, we present sequences of cyclins T1 from horse and dog and demonstrate that their N-terminal 300 residues rescue the transactivation of Tat from EIAV in human cells. Although human and equine cyclins T1 bind to this Tat, only the equine cyclin T1 supports the binding of Tat to TAR from EIAV. Finally, a reciprocal exchange of the valine for the leucine at position 29 in human and equine cyclins T1, respectively, renders the human cyclin T1 active and the equine cyclin T1 inactive for Tat transactivation from EIAV. Thus, the collaboration between a specific cyclin T1 and Tat for their high-affinity interaction with TAR is a common theme of lentiviral transactivation. PMID:10623752

  15. Enhanced sensitivity and resolution in (1)H solid-state NMR spectroscopy of paramagnetic complexes under very fast magic angle spinning.

    PubMed

    Wickramasinghe, Nalinda P; Shaibat, Medhat; Ishii, Yoshitaka

    2005-04-27

    High-resolution NMR spectroscopy for paramagnetic complexes in solids has been rarely performed because of its limited sensitivity and resolution due to large paramagnetic shifts and associated technical difficulties. The present study demonstrates that magic angle spinning (MAS) at speeds exceeding 20 kHz provides unusually high sensitivity and excellent resolution in 1H solid-state NMR (SSNMR) for paramagnetic systems. Spinning-speed dependence of 1H MAS spectra showed that very fast MAS (VFMAS) at 24-28 kHz enhanced sensitivity by a factor of 12-18, compared with the sensitivity of 1H SSNMR spectra under moderate MAS at 10 kHz, for Cu(dl-alanine)2.H2O and Mn(acac)3, for which the spectral ranges due to 1H paramagnetic shifts reach 200 and 1000 ppm, respectively. It was theoretically and experimentally confirmed that the absolute sensitivity of 1H VFMAS for small paramagnetic complexes such as Cu(dl-alanine)2 can be an order of magnitude higher than that of equimolar diamagnetic ligands because of short 1H T1 ( approximately 1 ms) of the paramagnetic systems and improved sensitivity under VFMAS. On the basis of this demonstrated high sensitivity, 1H SSNMR micro analysis of paramagnetic systems in a nanomole scale is proposed. Applications were performed on two polymorphs of Cu(II)(8-quinolinol)2, which is a suppressor of human cancer cells. It was demonstrated that 1H VFMAS SSNMR spectra accumulated for 20 nmol of the polycrystalline samples in 10 min enabled one to distinguish alpha- and beta-forms of Cu(II)(8-quinolinol)2 on the basis of shift positions and line widths. PMID:15839671

  16. Adjuvant chemotherapy of pT1a and pT1b breast carcinoma: results from the NEMESI study

    PubMed Central

    2012-01-01

    Background The prognosis of pT1a-pT1b breast cancer (BC) used to be considered very good, with a 10-y RFS of 90%. However, some retrospective studies reported a 10-y RFS of 81%–86% and suggested benefit from adjuvant systemic therapy. Methods To evaluate the variables that determined the choice of adjuvant chemotherapy and the type of chemotherapy delivered in pT1a-pT1b BC, we analysed the small tumours enrolled in the NEMESI study. Results Out of 1,894 patients with pathological stage I-II BC enrolled in NEMESI, 402 (21.2%) were pT1a-pT1b. Adjuvant chemotherapy was delivered in 127/402 (31.59%). Younger age, grading G3, high proliferative index, ER-negative and HER2-positive status were significantly associated with the decision to administer adjuvant chemotherapy. An anthracycline without taxane regimen was administered in 59.1% of patients, anthracycline with taxane in 24.4%, a CMF-like regimen in 14.2% and taxane in 2.4%. Adjuvant chemotherapy was administered in 88.4% triple-negative and 73.46% HER2-positive pT1a-pT1b BC. Adjuvant trastuzumab was delivered in 30/49 HER2-positive BC (61.2%). Conclusions Adjuvant chemotherapy was delivered in 31.59% T1a-pT1b BC treated at 63 Italian oncological centres from January 2008 to June 2008. The choice to deliver chemotherapy was based on biological prognostic factors. Anthracycline-based chemotherapy was administered in 83.5% patients. PMID:22545982

  17. T1R2 and T1R3 subunits are individually unnecessary for normal affective licking responses to Polycose: implications for saccharide taste receptors in mice.

    PubMed

    Treesukosol, Yada; Blonde, Ginger D; Spector, Alan C

    2009-04-01

    The T1R2 and T1R3 proteins are expressed in taste receptor cells and form a heterodimer binding with compounds described as sweet by humans. We examined whether Polycose taste might be mediated through this heterodimer by testing T1R2 knockout (KO) and T1R3 KO mice and their wild-type (WT) littermate controls in a series of brief-access taste tests (25-min sessions with 5-s trials). Sucrose, Na-saccharin, and Polycose were each tested for three consecutive sessions with order of presentation varied among subgroups in a Latin-Square manner. Both KO groups displayed blunted licking responses and initiated significantly fewer trials of sucrose and Na-saccharin across a range of concentrations. KO mice tested after Polycose exposure demonstrated some degree of concentration-dependent licking of sucrose, likely attributable to learning related to prior postingestive experience. These results are consistent with prior findings in the literature, implicating the T1R2+3 heterodimer as the principal taste receptor for sweet-tasting ligands, and also provide support for the potential of postingestive experience to influence responding in the KO mice. In contrast, T1R2 KO and T1R3 KO mice displayed concentration-dependent licking responses to Polycose that tracked those of their WT controls and in some cases licked midrange concentrations more; the number of Polycose trials initiated overall did not differ between KO and WT mice. Thus, the T1R2 and T1R3 proteins are individually unnecessary for normal concentration-dependent licking of Polycose to be expressed in a brief-access test. Whether at least one of these T1R protein subunits is necessary for normal Polycose responsiveness remains untested. Alternatively, there may be a novel taste receptor(s) that mediates polysaccharide taste. PMID:19158407

  18. Muscle regulatory factors regulate T1R3 taste receptor expression.

    PubMed

    Kokabu, Shoichiro; Lowery, Jonathan W; Toyono, Takashi; Seta, Yuji; Hitomi, Suzuro; Sato, Tsuyoshi; Enoki, Yuichiro; Okubo, Masahiko; Fukushima, Yosuke; Yoda, Tetsuya

    2015-12-25

    T1R3 is a T1R class of G protein-coupled receptors, composing subunit of the umami taste receptor when complexed with T1R1. T1R3 was originally discovered in gustatory tissue but is now known to be expressed in a wide variety of tissues and cell types such the intestine, pancreatic β-cells, skeletal muscle, and heart. In addition to taste recognition, the T1R1/T1R3 complex functions as an amino acid sensor and has been proposed to be a control mechanism for the secretion of hormones, such as cholecystokinin, insulin, and duodenal HCO3(-) and activates the mammalian rapamycin complex 1 (MTORC1) to inhibit autophagy. T1R3 knockout mice have increased rate of autophagy in the heart, skeletal muscle and liver. Thus, T1R3 has multiple physiological functions and is widely expressed in vivo. However, the exact mechanisms regulating T1R3 expression are largely unknown. Here, we used comparative genomics and functional analyses to characterize the genomic region upstream of the annotated transcriptional start of human T1R3. This revealed that the T1R3 promoter in human and mouse resides in an evolutionary conserved region (ECR). We also identified a repressive element located upstream of the human T1R3 promoter that has relatively high degree of conservation with rhesus macaque. Additionally, the muscle regulatory factors MyoD and Myogenin regulate T1R3 expression and T1R3 expression increases with skeletal muscle differentiation of murine myoblast C2C12 cells. Taken together, our study raises the possibility that MyoD and Myogenin might control skeletal muscle metabolism and homeostasis through the regulation of T1R3 promoter activity. PMID:26545778

  19. Synthesis, structure, photoluminescence and antitumour activity of zinc complex based on 2-(2-(1H-benzo-[d]imidazol-2-yl)benzyl)-1H-benzo-[d]imidazole

    NASA Astrophysics Data System (ADS)

    Che, Zhijian; Wang, Shaoxiang; Liu, Shenggui; Li, Guobi; Wu, Qiting; Lin, Chunyu; Kong, Linglang; Wang, Sheng

    2015-01-01

    A new complex [Zn(bbb)Cl2]·DMF, where bbb is 2-(2-(1H-benzo[d]imidazol-2-yl)benzyl)-1H-benzo[d]imidazole, was synthesized and characterized by element analysis, 1H NMR and X-ray single crystal structure analyses. For complex: crystal system, triclinic, space group, P-1, a = 9.4661(13), b = 10.3534(14), c = 13.0025(18) Å, α = 73.477(2), β = 80.743(2), γ = 88.658(2)°, V = 1205.5(3) Å3, Z = 2. In this complex, the Zn2+ distorted tetrahedron geometry is coordinated by two nitrogen atoms from 2-(2-(1H-benzo[d]imidazol-2-yl)benzyl)-1H-benzo[d]imidazole and two Cl-. The complex emits yellow green luminescence with the maximal emission peak at 550 nm in DMF solution. The complex exhibits inhibition on the growth of Eca109 cancer cell with IC50 value of 8.9 ± 1.1 μM, which was lower than that of cisplatin (14.3 ± 1.4 μM). This complex has potential application in treatment of esophageal cancer.

  20. Synthesis, in vitro protoporphyrinogen oxidase inhibition, and herbicidal activity of N-(benzothiazol-5-yl)hexahydro-1H-isoindole-1,3-diones and N-(benzothiazol-5-yl)hexahydro-1H-isoindol-1-ones.

    PubMed

    Wu, Qiong-You; Jiang, Li-Li; Zuo, Yang; Wang, Zhi-Fang; Xi, Zhen; Yang, Guang-Fu

    2014-10-01

    Protoporphyrinogen oxidase (EC 1.3.3.4) is one of the most significant targets for a large family of herbicides. As part of our continuous efforts to search for novel protoporphyrinogen oxidase-inhibiting herbicides, N-(benzothiazol-5-yl)tetrahydroisoindole-1,3-dione was selected as a lead compound for structural optimization, leading to the syntheses of a series of novel N-(benzothiazol-5-yl)hexahydro-1H-isoindole-1,3-diones (1a-o) and N-(benzothiazol-5-yl)hexahydro-1H-isoindol-1-ones (2a-i). These newly prepared compounds were characterized by elemental analyses, (1) H NMR, and ESI-MS, and the structures of 1h and 2h were further confirmed by X-ray diffraction analyses. The bioassays indicated that some compounds displayed comparable or higher protoporphyrinogen oxidase inhibition activities in comparison with the commercial control. Very promising, compound 2a, ethyl 2-((6-fluoro-5-(4,5,6,7-tetrahydro-1-oxo-1H-isoindol-2(3H)-yl)benzo[d]thiazol-2-yl)-sulfanyl)acetate, was recognized as the most potent candidate with K(i) value of 0.0091 μm. Further greenhouse screening results demonstrated that some compounds exhibited good herbicidal activity against Chenopodium album at the dosage of 150 g/ha. PMID:24803371

  1. T1ρ magnetic resonance: basic physics principles and applications in knee and intervertebral disc imaging

    PubMed Central

    Zhang, Qinwei; Li, Xiaojuan; Chen, Weitian; Ahuja, Anil; Yuan, Jing

    2015-01-01

    T1ρ relaxation time provides a new contrast mechanism that differs from T1- and T2-weighted contrast, and is useful to study low-frequency motional processes and chemical exchange in biological tissues. T1ρ imaging can be performed in the forms of T1ρ-weighted image, T1ρ mapping and T1ρ dispersion. T1ρ imaging, particularly at low spin-lock frequency, is sensitive to B0 and B1 inhomogeneity. Various composite spin-lock pulses have been proposed to alleviate the influence of field inhomogeneity so as to reduce the banding-like spin-lock artifacts. T1ρ imaging could be specific absorption rate (SAR) intensive and time consuming. Efforts to address these issues and speed-up data acquisition are being explored to facilitate wider clinical applications. This paper reviews the T1ρ imaging’s basic physic principles, as well as its application for cartilage imaging and intervertebral disc imaging. Compared to more established T2 relaxation time, it has been shown that T1ρ provides more sensitive detection of proteoglycan (PG) loss at early stages of cartilage degeneration. T1ρ has also been shown to provide more sensitive evaluation of annulus fibrosis (AF) degeneration of the discs. PMID:26807369

  2. Ultra-low field T1 vs. T1rho at 3T and 7T: study of rotationally immobilized protein gels and animal brain tissues

    NASA Astrophysics Data System (ADS)

    Dong, Hui; Inglis, Ben; Barr, Ian; Clarke, John

    2015-03-01

    Clinical magnetic resonance imaging (MRI) machines operating in static fields of typically 1.5 T or 3 T can capture information on slow molecular dynamics utilizing the so-called T1rho technique. This technique, in which a radiofrequency (RF) spin-lock field is applied with microtesla amplitude, has been used, for example, to determine the onset time of stroke in studies on rats. The long RF pulse, however, may exceed the specific absorption rate (SAR) limit, putting subjects at risk. Ultra-low-field (ULF) MRI, based on Superconducting Quantum Interference Devices (SQUIDs), directly detects proton signals at a static magnetic field of typically 50-250 μT. Using our ULF MRI system with adjustable static field of typically 55 to 240 μT, we systematically measured the T1 and T2 dispersion profiles of rotationally immobilized protein gels (bovine serum albumin), ex vivo pig brains, and ex vivo rat brains with induced stroke. Comparing the ULF results with T1rho dispersion obtained at 3 T and 7 T, we find that the degree of protein immobilization determines the frequency-dependence of both T1 and T1rho. Furthermore, T1rho and ULF T1 show similar results for stroke, suggesting that ULF MRI may be used to image traumatic brain injury with negligible SAR. This research was supported by the Henry H. Wheeler, Jr. Brain Imaging Center and the Donaldson Trust.

  3. Obtaining T1-T2 distribution functions from 1-dimensional T1 and T2 measurements: The pseudo 2-D relaxation model

    NASA Astrophysics Data System (ADS)

    Williamson, Nathan H.; Röding, Magnus; Galvosas, Petrik; Miklavcic, Stanley J.; Nydén, Magnus

    2016-08-01

    We present the pseudo 2-D relaxation model (P2DRM), a method to estimate multidimensional probability distributions of material parameters from independent 1-D measurements. We illustrate its use on 1-D T1 and T2 relaxation measurements of saturated rock and evaluate it on both simulated and experimental T1-T2 correlation measurement data sets. Results were in excellent agreement with the actual, known 2-D distribution in the case of the simulated data set. In both the simulated and experimental case, the functional relationships between T1 and T2 were in good agreement with the T1-T2 correlation maps from the 2-D inverse Laplace transform of the full 2-D data sets. When a 1-D CPMG experiment is combined with a rapid T1 measurement, the P2DRM provides a double-shot method for obtaining a T1-T2 relationship, with significantly decreased experimental time in comparison to the full T1-T2 correlation measurement.

  4. Obtaining T1-T2 distribution functions from 1-dimensional T1 and T2 measurements: The pseudo 2-D relaxation model.

    PubMed

    Williamson, Nathan H; Röding, Magnus; Galvosas, Petrik; Miklavcic, Stanley J; Nydén, Magnus

    2016-08-01

    We present the pseudo 2-D relaxation model (P2DRM), a method to estimate multidimensional probability distributions of material parameters from independent 1-D measurements. We illustrate its use on 1-D T1 and T2 relaxation measurements of saturated rock and evaluate it on both simulated and experimental T1-T2 correlation measurement data sets. Results were in excellent agreement with the actual, known 2-D distribution in the case of the simulated data set. In both the simulated and experimental case, the functional relationships between T1 and T2 were in good agreement with the T1-T2 correlation maps from the 2-D inverse Laplace transform of the full 2-D data sets. When a 1-D CPMG experiment is combined with a rapid T1 measurement, the P2DRM provides a double-shot method for obtaining a T1-T2 relationship, with significantly decreased experimental time in comparison to the full T1-T2 correlation measurement. PMID:27344611

  5. Comparison of T1ρ and T2* Relaxation Mapping in Patients with Different Grades of Disc Degeneration at 3T MR

    PubMed Central

    Zhang, Xinjuan; Yang, Li; Gao, Fei; Yuan, Zhenguo; Lin, Xiangtao; Yao, Bin; Chen, Weibo; Chan, Queenie; Wang, Guangbin

    2015-01-01

    Background T1ρ and T2* relaxation times are capable of providing information about early biochemical changes in intervertebral disk degeneration (IVDD). The purpose of this study was to assess and compare T1ρ and T2* mapping in IVDD with reference to Pfirrmann grade. Material/Methods Lumbar sagittal T2-weighted, T1ρ and T2* relaxation MRI were performed at 3.0T in 42 subjects covering discs L1–L2 to L5–S1. All the discs were morphologically assessed according to the Pfirrmann grade. Regions of interest (ROIs) were drawn over the T1ρ and T2*mappings, including nucleus pulposus (NP) and annulus fibrosus (AF). Wilcoxon signed rank test, Kruskal-Wallis test, and Spearman rank correlation were performed. Results The difference in T1ρ and T2* values between NP and AF were highly significant (P<0.001). The trends of decreasing T1ρ and T2* values of both NP and AF with increasing Pfirrmann grades was significant (P<0.01), particularly between Pfirrmann grade II and III (P<0.001), whereas T2* mapping was additionally able to detect changes in the AF between Pfirrmann grade I and II (P<0.05). Pfirrmann grades were inversely significantly correlated with both T1ρ and T2* values in the NP (r=–0.69, P<0.001; r=−0.56, P<0.001) and AF (r=−0.45, P<0.001; r=−0.26, P<0.001). Conclusions The process of IVDD can be detected by T1ρ and T2* mapping, particularly at early stage, and both methodologies displayed roughly comparable performance. PMID:26141783

  6. An optimized and validated (1)H NMR method for the quantification of α-pinene in essentials oils.

    PubMed

    Cerceau, Cristiane I; Barbosa, Luiz C A; Filomeno, Claudinei A; Alvarenga, Elson S; Demuner, Antônio J; Fidencio, Paulo H

    2016-04-01

    The authenticity and composition of commercial essential oils requires strict quality control. Due to the importance of α-pinene containing essential oils, a rapid and efficient method for quantification of this terpene in oils of eucalyptus, pink pepper and turpentine using (1)H NMR was developed and validated. All evaluated parameters (selectivity, linearity, accuracy/precision, repeatability, robustness, stability of analyte and internal standard in solutions) showed satisfactory results. The limit of detection (LOD) and limit of quantification (LOQ) were 0.1 and 2.5mg respectively. These values indicated that α-pinene was detected in 35 mg samples containing at least 0.3% of this compound. In addition, a minimum of 8% of α-pinene in the sample was required for quantification. Furthermore, the standard deviations found in the (1)H NMR methodology were less than 1% and were lower than those obtained by gas chromatographic analysis. Statistical tests have shown that the results obtained by (1)H NMR methodology are similar to those obtained by GC-FID technique using external and internal standardization and normalization within 95% confidence. R&R values lower than 10% have shown that all the methods are appropriate and the (1)H NMR method is suitable for quantification of α-pinene in samples of essential oils since this method possessed the smallest R&R (1.81) value. PMID:26838386

  7. 1H NMR metabolomics study of age profiling in children

    PubMed Central

    Gu, Haiwei; Pan, Zhengzheng; Xi, Bowei; Hainline, Bryan E.; Shanaiah, Narasimhamurthy; Asiago, Vincent; Nagana Gowda, G. A.; Raftery, Daniel

    2014-01-01

    Metabolic profiling of urine provides a fingerprint of personalized endogenous metabolite markers that correlate to a number of factors such as gender, disease, diet, toxicity, medication, and age. It is important to study these factors individually, if possible to unravel their unique contributions. In this study, age-related metabolic changes in children of age 12 years and below were analyzed by 1H NMR spectroscopy of urine. The effect of age on the urinary metabolite profile was observed as a distinct age-dependent clustering even from the unsupervised principal component analysis. Further analysis, using partial least squares with orthogonal signal correction regression with respect to age, resulted in the identification of an age-related metabolic profile. Metabolites that correlated with age included creatinine, creatine, glycine, betaine/TMAO, citrate, succinate, and acetone. Although creatinine increased with age, all the other metabolites decreased. These results may be potentially useful in assessing the biological age (as opposed to chronological) of young humans as well as in providing a deeper understanding of the confounding factors in the application of metabolomics. PMID:19441074

  8. Preliminary 1H NMR study on archaeological waterlogged wood.

    PubMed

    Maccotta, Antonella; Fantazzini, Paola; Garavaglia, Carla; Donato, Ines D; Perzia, Patrizia; Brai, Maria; Morreale, Filippa

    2005-01-01

    Magnetic Resonance Relaxation (MRR) and Magnetic Resonance Imaging (MRI) are powerful tools to obtain detailed information on the pore space structure that one is unlikely to obtain in other ways. These techniques are particularly suitable for Cultural Heritage materials, because they use water 1H nuclei as a probe. Interaction with water is one of the main causes of deterioration of materials. Porous structure in wood, for example, favours the penetration of water, which can carry polluting substances and promote mould growth. A particular case is waterlogged wood from underwater discoveries and moist sites; in fact, these finds are very fragile because of chemical, physical and biological decay from the long contact with the water. When wood artefacts are brought to the surface and directly dried in air, there is the collapse of the cellular structures, and wood loses its original form and dimensions and cannot be used for study and museum exhibits. In this work we have undertaken the study of some wood finds coming from Ercolano's harbour by MRR and MRI under different conditions, and we have obtained a characterization of pore space in wood and images of the spatial distribution of the confined water in the wood. PMID:16485652

  9. 3-hydroxy-2(1H)-pyridinone chelating agents

    DOEpatents

    Raymond, K.N.; Xu, J.

    1997-04-29

    Disclosed is a series of improved metal chelating agents, which are highly effective upon both injection and oral administration; several of the most effective are of low toxicity. These chelating agents incorporate within their structure 1-hydroxy-2-pyridinone (1,2-HOPO) and 3-hydroxy-2-pyridinone (3,2-HOPO) moieties with a substituted carbamoyl group ortho to the hydroxy or oxo groups of the hydroxypyridinone ring. The electron-withdrawing carbamoyl group increases the acidity of the hydroxypyridinones. In the metal complexes of the chelating agents, the amide protons form very strong hydrogen bonds with its adjacent HOPO oxygen donor, making these complexes very stable at physiological conditions. The terminal N-substituents provides a certain degree of lipophilicity to the 3,2-HOPO, increasing oral activity. Also disclosed is a method of making the chelating agents and a method of producing a known compound, 3-hydroxy-1-alkyl-2(1H)pyridinone, used as a precursor to the chelating agent, safely and in large quantities. 2 figs.

  10. 3-hydroxy-2(1H)-pyridinone chelating agents

    DOEpatents

    Raymond, Kenneth N.; Xu, Jide

    1997-01-01

    Disclosed is a series of improved metal chelating agents, which are highly effective upon both injection and oral administration; several of the most effective are of low toxicity. These chelating agents incorporate within their structure 1-hydroxy-2-pyridinone (1,2-HOPO) and 3-hydroxy-2-pyridinone (3,2-HOPO) moieties with a substituted carbamoyl group ortho to the hydroxy or oxo groups of the hydroxypyridinone ring. The electron-withdrawing carbamoyl group increases the acidity of the hydroxypyridinones. In the metal complexes of said chelating agents, the amide protons form very strong hydrogen bonds with its adjacent HOPO oxygen donor, making these complexes very stable at physiological conditions. The terminal N-substituents provides a certain degree of lipophilicity to said 3,2-HOPO, increasing oral activity. Also disclosed is a method of making the chelating agents and a method of producing a known compound, 3-hydroxy-1-alkyl-2(1H)pyridinone, used as a precursor to the chelating agent, safely and in large quantities.

  11. 1H NMR Metabolomics Analysis of Glioblastoma Subtypes

    PubMed Central

    Cuperlovic-Culf, Miroslava; Ferguson, Dean; Culf, Adrian; Morin, Pier; Touaibia, Mohamed

    2012-01-01

    Glioblastoma multiforme (GBM) is the most common form of malignant glioma, characterized by unpredictable clinical behaviors that suggest distinct molecular subtypes. With the tumor metabolic phenotype being one of the hallmarks of cancer, we have set upon to investigate whether GBMs show differences in their metabolic profiles. 1H NMR analysis was performed on metabolite extracts from a selection of nine glioblastoma cell lines. Analysis was performed directly on spectral data and on relative concentrations of metabolites obtained from spectra using a multivariate regression method developed in this work. Both qualitative and quantitative sample clustering have shown that cell lines can be divided into four groups for which the most significantly different metabolites have been determined. Analysis shows that some of the major cancer metabolic markers (such as choline, lactate, and glutamine) have significantly dissimilar concentrations in different GBM groups. The obtained lists of metabolic markers for subgroups were correlated with gene expression data for the same cell lines. Metabolic analysis generally agrees with gene expression measurements, and in several cases, we have shown in detail how the metabolic results can be correlated with the analysis of gene expression. Combined gene expression and metabolomics analysis have shown differential expression of transporters of metabolic markers in these cells as well as some of the major metabolic pathways leading to accumulation of metabolites. Obtained lists of marker metabolites can be leveraged for subtype determination in glioblastomas. PMID:22528487

  12. Fatty acids profile of Sacha Inchi oil and blends by 1H NMR and GC-FID.

    PubMed

    Vicente, Juarez; de Carvalho, Mario Geraldo; Garcia-Rojas, Edwin E

    2015-08-15

    This study aimed at the characterization of blends of Sacha Inchi oil (SIO) with different ratios of SO (soybean oil) and CO (corn oil) by nuclear magnetic resonance ((1)H NMR), compared with the data obtained by gas chromatography with a flame ionization detector (GC-FID). The (1)H NMR and GC-FID data from different ratios of SIO were adjusted by a second order polynomial equation. The two techniques were highly correlated (R(2) values ranged from 0.995 to 0.999), revealing that (1)H NMR is an efficient methodology for the quantification of omega-3 fatty acids in oils rich in omega-6 fatty acids or vice versa such as SO and CO and, on the other hand, can be used to quantify ω-6 in oils rich in ω-3, such as SIO. PMID:25794742

  13. Mild hydration of didecyldimethylammonium chloride modified DNA by 1H-nuclear magnetic resonance and by sorption isotherm

    NASA Astrophysics Data System (ADS)

    Harańczyk, H.; Kobierski, J.; Nizioł, J.; Hebda, E.; Pielichowski, J.; Zalitacz, D.; Marzec, M.; El-Ghayoury, A.

    2013-01-01

    The gaseous phase hydration of deoxyribonucleic acid and didecyldimethylammonium chloride (C19H42ClN) complexes (DNA-DDCA) was observed using hydration kinetics, sorption isotherm, and high power nuclear magnetic resonance. Three bound water fractions were distinguished: (i) a very tightly bound water not removed by incubation over silica gel, (ii) a tightly bound water saturating with the hydration time t1h = (0.59 ± 0.04) h, and a loosely bound water fraction, (iii) with the hydration time t2h = (20.9 ± 1.3) h. Proton free induction decay was decomposed into the signal associated with the solid matrix of DNA-DDCA complex (T2S∗≈ 30 μs) and two liquid signal components coming from tightly bound (T2L1∗≈ 100 μs) and from loosely bound water fraction (T2L2∗≈ 1000 μs).

  14. Fully automatic detection of deep white matter T1 hypointense lesions in multiple sclerosis

    NASA Astrophysics Data System (ADS)

    Spies, Lothar; Tewes, Anja; Suppa, Per; Opfer, Roland; Buchert, Ralph; Winkler, Gerhard; Raji, Alaleh

    2013-12-01

    A novel method is presented for fully automatic detection of candidate white matter (WM) T1 hypointense lesions in three-dimensional high-resolution T1-weighted magnetic resonance (MR) images. By definition, T1 hypointense lesions have similar intensity as gray matter (GM) and thus appear darker than surrounding normal WM in T1-weighted images. The novel method uses a standard classification algorithm to partition T1-weighted images into GM, WM and cerebrospinal fluid (CSF). As a consequence, T1 hypointense lesions are assigned an increased GM probability by the standard classification algorithm. The GM component image of a patient is then tested voxel-by-voxel against GM component images of a normative database of healthy individuals. Clusters (≥0.1 ml) of significantly increased GM density within a predefined mask of deep WM are defined as lesions. The performance of the algorithm was assessed on voxel level by a simulation study. A maximum dice similarity coefficient of 60% was found for a typical T1 lesion pattern with contrasts ranging from WM to cortical GM, indicating substantial agreement between ground truth and automatic detection. Retrospective application to 10 patients with multiple sclerosis demonstrated that 93 out of 96 T1 hypointense lesions were detected. On average 3.6 false positive T1 hypointense lesions per patient were found. The novel method is promising to support the detection of hypointense lesions in T1-weighted images which warrants further evaluation in larger patient samples.

  15. Fully automatic detection of deep white matter T1 hypointense lesions in multiple sclerosis.

    PubMed

    Spies, Lothar; Tewes, Anja; Suppa, Per; Opfer, Roland; Buchert, Ralph; Winkler, Gerhard; Raji, Alaleh

    2013-12-01

    A novel method is presented for fully automatic detection of candidate white matter (WM) T1 hypointense lesions in three-dimensional high-resolution T1-weighted magnetic resonance (MR) images. By definition, T1 hypointense lesions have similar intensity as gray matter (GM) and thus appear darker than surrounding normal WM in T1-weighted images. The novel method uses a standard classification algorithm to partition T1-weighted images into GM, WM and cerebrospinal fluid (CSF). As a consequence, T1 hypointense lesions are assigned an increased GM probability by the standard classification algorithm. The GM component image of a patient is then tested voxel-by-voxel against GM component images of a normative database of healthy individuals. Clusters (≥0.1 ml) of significantly increased GM density within a predefined mask of deep WM are defined as lesions. The performance of the algorithm was assessed on voxel level by a simulation study. A maximum dice similarity coefficient of 60% was found for a typical T1 lesion pattern with contrasts ranging from WM to cortical GM, indicating substantial agreement between ground truth and automatic detection. Retrospective application to 10 patients with multiple sclerosis demonstrated that 93 out of 96 T1 hypointense lesions were detected. On average 3.6 false positive T1 hypointense lesions per patient were found. The novel method is promising to support the detection of hypointense lesions in T1-weighted images which warrants further evaluation in larger patient samples. PMID:24216694

  16. Bolus-tracking MRI with a simultaneous T1- and T2*-measurement.

    PubMed

    Sourbron, S; Heilmann, M; Biffar, A; Walczak, C; Vautier, J; Volk, A; Peller, M

    2009-09-01

    The aim of this study was to propose and evaluate a methodology to analyze simultaneously acquired T2*-weighted dynamic susceptibility contrast (DSC) MRI and T(1)-weighted dynamic contrast enhanced (DCE) MRI data. Two generalized models of T2*-relaxation are proposed to account for tracer leakage, and a two-compartment exchange model is used to separate tracer in intra- and extravascular spaces. The methods are evaluated using data extracted from ROIs in three mice with subcutaneously implanted human colorectal tumors. Comparing plasma flow values obtained from DCE-MRI and DSC-MRI data defines a practical experimental paradigm to measure T2*-relaxivities, and reveals a factor of 15 between values in tissue and blood. Comparing mean transit time values obtained from DCE-MRI and DSC-MRI without leakage correction, indicates a significant reduction of susceptibility weighting in DSC-MRI during tracer leakage. A one-parameter gradient correction model provides a good approximation for this susceptibility loss, but redundancy of the parameter limits the practical potential of this model for DSC-MRI. Susceptibility loss is modeled more accurately with a variable T2*-relaxivity, which allows to extract new parameters that cannot be derived from DSC-MRI or DCE-MRI alone. They reflect the cellular and vessel geometry, and thus may lead to a more complete characterization of tissue structure. PMID:19585599

  17. Quantitative diffusion-weighted magnetic resonance imaging in the assessment of myocardial fibrosis in hypertrophic cardiomyopathy compared with T1 mapping.

    PubMed

    Wu, Lian-Ming; Chen, Bing-Hua; Yao, Qiu-Ying; Ou, Yang-Rongzheng; Wu, Rui; Jiang, Meng; Hu, Jiani; An, Dong-Aolei; Xu, Jian-Rong

    2016-08-01

    To identify myocardial fibrosis in hypertrophic cardiomyopathy (HCM) subjects using quantitative cardiac diffusion-weighted imaging (DWI) and to compare its performance with native T1 mapping and extracellular volume (ECV). Thirty-eight HCM subjects (mean age, 53 ± 9 years) and 14 normal controls (mean age, 51 ± 8 years) underwent cardiac magnetic resonance imaging (CMRI) on a 3.0T magnetic resonance (MR) machine with DWI, T1 mapping and late gadolinium enhancement (LGE) imaging as the reference standard. The mean apparent diffusion coefficient (ADC), native T1 value and ECV were determined for each subject. Overall, the HCM subjects exhibited an increased native T1 value (1241.04 ± 78.50 ms), ECV (0.31 ± 0.03) and ADC (2.36 ± 0.34 s/mm(2)) compared with the normal controls (1114.60 ± 37.99 ms, 0.24 ± 0.04, and 1.62 ± 0.38 s/mm(2), respectively) (p < 0.05). DWI differentiated healthy and fibrotic myocardia with an area under the curve (AUC) of 0.93, while the AUCs of the native T1 values (0.93), (p > 0.05) and ECV (0.94), (p > 0.05) exhibited an equal differentiation ability. Both HCM LGE+ and HCM LGE- subjects had an increased native T1 value, ECV and ADC compared to the normal controls (p < 0.05). HCM LGE+ subjects exhibited an increased ECV (0.31 ± 0.04) and ADC (2.43 ± 0.36 s/mm(2)) compared to HCM LGE- subjects (p < 0.05). HCM LGE+ and HCM LGE- subjects had similar native T1 values (1250 ± 76.36 ms vs. 1213.98 ± 92.30 ms, respectively) (p > 0.05). ADC values were linearly associated with increased ECV (R(2) = 0.36) and native T1 values (R(2) = 0.40) among all subjects. DWI is a feasible alternative to native T1 mapping and ECV for the identification of myocardial fibrosis in patients with HCM. DWI and ECV can quantitatively characterize the extent of fibrosis in HCM LGE+ and HCM LGE- patients. PMID:27198892

  18. Sugar-induced cephalic-phase insulin release is mediated by a T1r2+T1r3-independent taste transduction pathway in mice.

    PubMed

    Glendinning, John I; Stano, Sarah; Holter, Marlena; Azenkot, Tali; Goldman, Olivia; Margolskee, Robert F; Vasselli, Joseph R; Sclafani, Anthony

    2015-09-01

    Sensory stimulation from foods elicits cephalic phase responses, which facilitate digestion and nutrient assimilation. One such response, cephalic-phase insulin release (CPIR), enhances glucose tolerance. Little is known about the chemosensory mechanisms that activate CPIR. We studied the contribution of the sweet taste receptor (T1r2+T1r3) to sugar-induced CPIR in C57BL/6 (B6) and T1r3 knockout (KO) mice. First, we measured insulin release and glucose tolerance following oral (i.e., normal ingestion) or intragastric (IG) administration of 2.8 M glucose. Both groups of mice exhibited a CPIR following oral but not IG administration, and this CPIR improved glucose tolerance. Second, we examined the specificity of CPIR. Both mouse groups exhibited a CPIR following oral administration of 1 M glucose and 1 M sucrose but not 1 M fructose or water alone. Third, we studied behavioral attraction to the same three sugar solutions in short-term acceptability tests. B6 mice licked more avidly for the sugar solutions than for water, whereas T1r3 KO mice licked no more for the sugar solutions than for water. Finally, we examined chorda tympani (CT) nerve responses to each of the sugars. Both mouse groups exhibited CT nerve responses to the sugars, although those of B6 mice were stronger. We propose that mice possess two taste transduction pathways for sugars. One mediates behavioral attraction to sugars and requires an intact T1r2+T1r3. The other mediates CPIR but does not require an intact T1r2+T1r3. If the latter taste transduction pathway exists in humans, it should provide opportunities for the development of new treatments for controlling blood sugar. PMID:26157055

  19. Sugar-induced cephalic-phase insulin release is mediated by a T1r2+T1r3-independent taste transduction pathway in mice

    PubMed Central

    Stano, Sarah; Holter, Marlena; Azenkot, Tali; Goldman, Olivia; Margolskee, Robert F.; Vasselli, Joseph R.; Sclafani, Anthony

    2015-01-01

    Sensory stimulation from foods elicits cephalic phase responses, which facilitate digestion and nutrient assimilation. One such response, cephalic-phase insulin release (CPIR), enhances glucose tolerance. Little is known about the chemosensory mechanisms that activate CPIR. We studied the contribution of the sweet taste receptor (T1r2+T1r3) to sugar-induced CPIR in C57BL/6 (B6) and T1r3 knockout (KO) mice. First, we measured insulin release and glucose tolerance following oral (i.e., normal ingestion) or intragastric (IG) administration of 2.8 M glucose. Both groups of mice exhibited a CPIR following oral but not IG administration, and this CPIR improved glucose tolerance. Second, we examined the specificity of CPIR. Both mouse groups exhibited a CPIR following oral administration of 1 M glucose and 1 M sucrose but not 1 M fructose or water alone. Third, we studied behavioral attraction to the same three sugar solutions in short-term acceptability tests. B6 mice licked more avidly for the sugar solutions than for water, whereas T1r3 KO mice licked no more for the sugar solutions than for water. Finally, we examined chorda tympani (CT) nerve responses to each of the sugars. Both mouse groups exhibited CT nerve responses to the sugars, although those of B6 mice were stronger. We propose that mice possess two taste transduction pathways for sugars. One mediates behavioral attraction to sugars and requires an intact T1r2+T1r3. The other mediates CPIR but does not require an intact T1r2+T1r3. If the latter taste transduction pathway exists in humans, it should provide opportunities for the development of new treatments for controlling blood sugar. PMID:26157055

  20. Characterisation of the 1H and 13C NMR spectra of N-acetylaspartylglutamate and its detection in urine from patients with Canavan disease.

    PubMed

    Krawczyk, Hanna; Gradowska, Wanda

    2003-03-10

    1H and 13C NMR spectra of N-acetylaspartylglutamate (NAAG) have been recorded and interpreted. The values of the 1H chemical shifts and 1H-(1)H coupling constants at different pH were obtained by iterative computer fitting of 1-D 1H NMR spectra. This provided information on the solution conformation of the investigated molecule. Proton-decoupled high resolution 13C NMR spectra of NAAG have been measured in a series of dilute water solution of various acidity. These data have provided a basis for unequivocal determination of the presence of NAAG in the urine sample of a patient suffering from Canavan disease. NMR spectroscopy provides a possibility of detecting NAAG in body fluids. PMID:12615232

  1. 31P MRSI and 1H MRS at 7 T: initial results in human breast cancer.

    PubMed

    Klomp, Dennis W J; van de Bank, Bart L; Raaijmakers, Alexander; Korteweg, Mies A; Possanzini, Cecilia; Boer, Vincent O; van de Berg, Cornelius A T; van de Bosch, Maurice A A J; Luijten, Peter R

    2011-12-01

    This study demonstrates the feasibility of the noninvasive determination of important biomarkers of human (breast) tumor metabolism using high-field (7-T) MRI and MRS. (31) P MRSI at this field strength was used to provide a direct method for the in vivo detection and quantification of endogenous biomarkers. These encompass phospholipid metabolism, phosphate energy metabolism and intracellular pH. A double-tuned, dual-element transceiver was designed with focused radiofrequency fields for unilateral breast imaging and spectroscopy tuned for optimized sensitivity at 7 T. T(1) -weighted three-dimensional MRI and (1) H MRS were applied for the localization and quantification of total choline compounds. (31) P MRSI was obtained within 20 min per subject and mapped in three dimensions over the breast with pixel volumes of 10 mL. The feasibility of monitoring in vivo metabolism was demonstrated in two patients with breast cancer during neoadjuvant chemotherapy, validated by ex vivo high-resolution magic angle spinning NMR and compared with data from an age-matched healthy volunteer. Concentrations of total choline down to 0.4 mM could be detected in the human breast in vivo. Levels of adenosine and other nucleoside triphosphates, inorganic phosphate, phosphocholine, phosphoethanolamine and their glycerol diesters detected in glandular tissue, as well as in tumor, were mapped over the entire breast. Altered levels of these compounds were observed in patients compared with an age-matched healthy volunteer; modulation of these levels occurred in breast tumors during neoadjuvant chemotherapy. To our knowledge, this is the first comprehensive MRI and MRS study in patients with breast cancer, which reveals detailed information on the morphology and phospholipid metabolism from volumes as small as 10 mL. This endogenous metabolic information may provide a new method for the noninvasive assessment of prognostic and predictive biomarkers in breast cancer treatment. PMID

  2. Change of translational-rotational coupling in liquids revealed by field-cycling 1H NMR

    NASA Astrophysics Data System (ADS)

    Meier, R.; Schneider, E.; Rössler, E. A.

    2015-01-01

    Applying the field-cycling nuclear magnetic resonance technique, the frequency dependence of the 1H spin-lattice relaxation rate, R 1 ω = T1 - 1 ω , is measured for propylene glycol (PG) which is increasingly diluted with deuterated chloroform. A frequency range of 10 kHz-20 MHz and a broad temperature interval from 220 to about 100 K are covered. The results are compared to those of experiments, where glycerol and o-terphenyl are diluted with their deuterated counter-part. Reflecting intra- as well as intermolecular relaxation, the dispersion curves R 1 ω , x (x denotes mole fraction PG) allow to extract the rotational time constant τrot(T, x) and the self-diffusion coefficient D(T, x) in a single experiment. The Stokes-Einstein-Debye (SED) relation is tested in terms of the quantity D(T, x) τrot(T, x) which provides a measure of an effective hydrodynamic radius or equivalently of the spectral separation of the translational and the rotational relaxation contribution. In contrast to o-terphenyl, glycerol and PG show a spectral separation much larger than suggested by the SED relation. In the case of PG/chloroform mixtures, not only an acceleration of the PG dynamics is observed with increasing dilution but also the spectral separation of rotational and translational relaxation contributions continuously decreases. Finally, following a behavior similar to that of o-terphenyl already at about x = 0.6; i.e., while D(T, x) τrot(T, x) in the mixture is essentially temperature independent, it strongly increases with x signaling thus a change of translational-rotational coupling. This directly reflects the dissolution of the hydrogen-bond network and thus a change of solution structure.

  3. Assessment of the evaluation of liver T1 mapping imaging applying virtual ECG gating on a modified look-locker inversion recovery (MOLLI) pulse sequence

    NASA Astrophysics Data System (ADS)

    Yu, Seung-Man; Goo, Eun-Hoe; Lee, Suk-Jun; Choe, Bo-Young

    2014-10-01

    A T1 mapping calculation error may occur in a physicochemical environment with large relaxivity. We evaluated through a simulated electrocardiogram (ECG) the administration of a contrast with high relaxivity and its effect on the heart rate by using a modified Look-Locker inversion recovery (MOLLI) pulse sequence. The agarose 2% phantom of high relaxivity environment was developed by diluting gadoxetic acid magnetic resonance imaging (MRI) T1 contrast media. The gold standard T1 determination was based on coronal single section imaging with a 2D inversion-recovery turbo spin echo sequence (2D-IRTSE) in a 3T MR unit. Using the identical 3T MR scanner, we acquired T1 mapping for the MOLLI pulse sequence with various virtual heart rates. T1 mapping data of the two different pulse sequences ( i.e., 2D-IRTSE and MOLLI) were measured to investigate the accuracy and the specificity. An in vivo study was conducted in the same manner as the phantom experiments for liver T1 mapping imaging in three healthy volunteers. The MOLLI pulse sequence showed an error rate of less than 10% at a contrast agent concentration of 0.4 mmol/L, and significant error, compared with the reference value, was observed at 0.6 mmol/L or higher. The percentage error of the T1 value did not correlated with the RR ( i.e., the time between heart beats) change that was observed (P =.270). Based on the in-vivo liver test, T1 mapping imaging of an abdominal organ as the liver can be successfully achieved using the applied virtual ECG gating on the MOLLI sequence.

  4. Taste responses in mice lacking taste receptor subunit T1R1

    PubMed Central

    Kusuhara, Yoko; Yoshida, Ryusuke; Ohkuri, Tadahiro; Yasumatsu, Keiko; Voigt, Anja; Hübner, Sandra; Maeda, Katsumasa; Boehm, Ulrich; Meyerhof, Wolfgang; Ninomiya, Yuzo

    2013-01-01

    The T1R1 receptor subunit acts as an umami taste receptor in combination with its partner, T1R3. In addition, metabotropic glutamate receptors (brain and taste variants of mGluR1 and mGluR4) are thought to function as umami taste receptors. To elucidate the function of T1R1 and the contribution of mGluRs to umami taste detection in vivo, we used newly developed knock-out (T1R1−/−) mice, which lack the entire coding region of the Tas1r1 gene and express mCherry in T1R1-expressing cells. Gustatory nerve recordings demonstrated that T1R1−/− mice exhibited a serious deficit in inosine monophosphate-elicited synergy but substantial residual responses to glutamate alone in both chorda tympani and glossopharyngeal nerves. Interestingly, chorda tympani nerve responses to sweeteners were smaller in T1R1−/− mice. Taste cell recordings demonstrated that many mCherry-expressing taste cells in T1R1+/− mice responded to sweet and umami compounds, whereas those in T1R1−/− mice responded to sweet stimuli. The proportion of sweet-responsive cells was smaller in T1R1−/− than in T1R1+/− mice. Single-cell RT-PCR demonstrated that some single mCherry-expressing cells expressed all three T1R subunits. Chorda tympani and glossopharyngeal nerve responses to glutamate were significantly inhibited by addition of mGluR antagonists in both T1R1−/− and T1R1+/− mice. Conditioned taste aversion tests demonstrated that both T1R1−/− and T1R1+/− mice were equally capable of discriminating glutamate from other basic taste stimuli. Avoidance conditioned to glutamate was significantly reduced by addition of mGluR antagonists. These results suggest that T1R1-expressing cells mainly contribute to umami taste synergism and partly to sweet sensitivity and that mGluRs are involved in the detection of umami compounds. PMID:23339178

  5. Mapping extracellular pH in rat brain gliomas in vivo by 1H magnetic resonance spectroscopic imaging: comparison with maps of metabolites.

    PubMed

    García-Martín, M L; Hérigault, G; Rémy, C; Farion, R; Ballesteros, P; Coles, J A; Cerdán, S; Ziegler, A

    2001-09-01

    The value of extracellular pH (pH(e)) in tumors is an important factor in prognosisand choice of therapy. We demonstrate here that pH(e) can be mappedin vivo in a rat brain glioma by (1)H magnetic resonance spectroscopic imaging (SI) of the pH buffer (+/-)2-imidazole-1-yl-3-ethoxycarbonylpropionic acid (IEPA). (1)H SI also allowed us to map metabolites, and, to better understand the determinants of pH(e), we compared maps of pH(e), metabolites, and the distribution of the contrast agent gadolinium1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraaceticacid (Gd-DOTA). C6 cells injected in caudate nuclei of four Wistar rats gave rise to gliomas of approximately 10 mm in diameter. Three mmols of IEPA were injected in the right jugular vein from t = 0 to t = 60 min. From t = 50 min to t = 90 min, spin-echo (1)H SI was performed with an echo time of 40 ms in a 2.5-mm slice including the glioma (nominal voxel size, 2.2 microl). IEPA resonances were detected only within the glioma and were intense enough for pH(e) to be calculated from the chemical shift of the H2 resonance in almost all voxels of the glioma. (1)H spectroscopic images with an echo time of 136 ms were then acquired to map metabolites: lactate, choline-containing compounds (tCho), phosphocreatine/creatine, and N-acetylaspartate. Finally, T(1)-weighted imaging after injection of a bolus of Gd-DOTA gave a map indicative of extravasation. On average, the gradient of pH(e) (measured where sufficient IEPA was present) from the center to the periphery was not statistically significant. Mean pH(e) was calculated for each of the four gliomas, and the average was 7.084 +/- 0.017 (+/- SE; n = 4 rats), which is acid with respect to pH(e) of normal tissue. After normalization of spectra to their water peak, voxel-by-voxel comparisons of peak areas showed that N-acetylaspartate, a marker of neurons, correlated negatively with IEPA (P < 0.0001) and lactate (P < 0.05), as expected of a glioma surrounded by normal tissue. t

  6. Focal liver lesions hyperintense on T1-weighted magnetic resonance images.

    PubMed

    Furlan, Alessandro; Marin, Daniele; Bae, Kyongtae T; Lagalla, Roberto; Agnello, Francesco; Bazzocchi, Massimo; Brancatelli, Giuseppe

    2009-10-01

    This article reviews focal liver lesions hyperintense on T1-weighted magnetic resonance (MR) images and describes the underlying etiologies associated with their T1 signal intensity. Although focal liver lesions are commonly detected because of their iso- or hypointensity on T1-weighted images, lesions (benign or malignant) may present with T1 hyperintensity when they contain T1 shortening elements--such as fat, hemorrhage, copper, melanin, and highly concentrated proteins. Our discussion includes the description of state-of-the-art T1-weighted MR sequences and the imaging features of lesions on pre- and postcontrast MR images that are characteristic for lesion composition and useful for making accurate diagnosis. PMID:19842568

  7. Molecular structures of 2-arylaminomethyl-1H-benzimidazole: Spectral, electrochemical, DFT and biological studies

    NASA Astrophysics Data System (ADS)

    Abdel Ghani, Nour T.; Mansour, Ahmed M.

    2012-06-01

    In the present work, structural studies on (1H-benzimidazol-2-ylmethyl)-N-(4-chloro-phenyl)-amine (L1) and (1H-benzimidazol-2-ylmethyl)-N-(4-iodo-phenyl)-amine (L2) have been done extensively by a variety of physico-chemical techniques. Optimized geometrical structures, harmonic vibrational frequencies, natural bonding orbital (NBO) analysis, and Frontier molecular orbitals (FMO) were obtained by DFT/B3LYP method. TD-DFT calculations help to assign the electronic transitions. The polarizable continuum model (PCM) fails to describe the experimental chemical shift associated with the NH protons as calculated by applying Gauge-invariant atomic orbital (GIAO) method, but a very good correlation between the theoretical and experimental values was achieved by taking into account the specific solute-solvent interactions. DFT calculations showed a good agreement between the theoretical and observed results. These compounds exhibited a high biological activity through the inhibition of the metabolic growth of the investigated bacteria.

  8. Low Temperature 1H MAS NMR Spectroscopy Studies of Proton Motion in Zeolite

    SciTech Connect

    Huo, H.; Peng, L; Grey, C

    2009-01-01

    Low temperature {sup 1}H MAS NMR spectroscopy is used to study protonic motion in zeolite HZSM-5 in both samples that have been dried using procedures that are standard in the literature and samples that have been more carefully dehydrated. A significant enhancement of proton mobility is seen for the ''standard'' dehydrated HZSM-5 sample in comparison to that seen for the much drier sample. This is ascribed to a vehicle-hopping mechanism involving the residual water that is present in these zeolites. A gradual change of the framework structure is observed on cooling to approximately 213 K, as monitored via the change in {sup 1}H chemical shift values of the Broensted acid resonances and by X-ray diffraction. A more sudden change in structure is seen by differential scanning calorimetry and NMR at approximately 220?230 K, which is associated with changes in both the mobility and the modes of binding of the residual water to the Broensted acid sites and the zeolite framework.

  9. Taste substance binding elicits conformational change of taste receptor T1r heterodimer extracellular domains

    PubMed Central

    Nango, Eriko; Akiyama, Shuji; Maki-Yonekura, Saori; Ashikawa, Yuji; Kusakabe, Yuko; Krayukhina, Elena; Maruno, Takahiro; Uchiyama, Susumu; Nuemket, Nipawan; Yonekura, Koji; Shimizu, Madoka; Atsumi, Nanako; Yasui, Norihisa; Hikima, Takaaki; Yamamoto, Masaki; Kobayashi, Yuji; Yamashita, Atsuko

    2016-01-01

    Sweet and umami tastes are perceived by T1r taste receptors in oral cavity. T1rs are class C G-protein coupled receptors (GPCRs), and the extracellular ligand binding domains (LBDs) of T1r1/T1r3 and T1r2/T1r3 heterodimers are responsible for binding of chemical substances eliciting umami or sweet taste. However, molecular analyses of T1r have been hampered due to the difficulties in recombinant expression and protein purification, and thus little is known about mechanisms for taste perception. Here we show the first molecular view of reception of a taste substance by a taste receptor, where the binding of the taste substance elicits a different conformational state of T1r2/T1r3 LBD heterodimer. Electron microscopy has showed a characteristic dimeric structure. Förster resonance energy transfer and X-ray solution scattering have revealed the transition of the dimerization manner of the ligand binding domains, from a widely spread to compactly organized state upon taste substance binding, which may correspond to distinct receptor functional states. PMID:27160511

  10. Taste substance binding elicits conformational change of taste receptor T1r heterodimer extracellular domains.

    PubMed

    Nango, Eriko; Akiyama, Shuji; Maki-Yonekura, Saori; Ashikawa, Yuji; Kusakabe, Yuko; Krayukhina, Elena; Maruno, Takahiro; Uchiyama, Susumu; Nuemket, Nipawan; Yonekura, Koji; Shimizu, Madoka; Atsumi, Nanako; Yasui, Norihisa; Hikima, Takaaki; Yamamoto, Masaki; Kobayashi, Yuji; Yamashita, Atsuko

    2016-01-01

    Sweet and umami tastes are perceived by T1r taste receptors in oral cavity. T1rs are class C G-protein coupled receptors (GPCRs), and the extracellular ligand binding domains (LBDs) of T1r1/T1r3 and T1r2/T1r3 heterodimers are responsible for binding of chemical substances eliciting umami or sweet taste. However, molecular analyses of T1r have been hampered due to the difficulties in recombinant expression and protein purification, and thus little is known about mechanisms for taste perception. Here we show the first molecular view of reception of a taste substance by a taste receptor, where the binding of the taste substance elicits a different conformational state of T1r2/T1r3 LBD heterodimer. Electron microscopy has showed a characteristic dimeric structure. Förster resonance energy transfer and X-ray solution scattering have revealed the transition of the dimerization manner of the ligand binding domains, from a widely spread to compactly organized state upon taste substance binding, which may correspond to distinct receptor functional states. PMID:27160511

  11. Change in the Proton T1 of Fat and Water in Mixture

    PubMed Central

    Hu, Houchun H.; Nayak, Krishna S.

    2010-01-01

    This work describes observed changes in the proton T1 relaxation time of both water and lipid when they are in relatively homogeneous mixtures. Results obtained from vegetable oil–water emulsions, pork kidney and lard mixtures, and excised samples of white and brown adipose tissues are presented to demonstrate this change in T1 as a function of mixture fat fraction. As an initial proof of concept, a simpler acetone-water experiment was performed to take advantage of complete miscibility between acetone and water and both components’ single chemical shift peaks. Single-voxel MR spectroscopy was used to measure the T1 of predominant methylene spins in fat and the T1 of water spins in each setup. In the vegetable oil–water emulsions, the T1 of fat varied by as much as 3-fold when water was the dominant mixture component. The T1 of pure lard increased by 170 msec (+37%) when it was blended with lean kidney tissue in a 16% fatty mixture. The fat T1 of lipid-rich white adipose tissue was 312 msec. In contrast, the fat T1 of leaner brown adipose tissue (fat fraction 53%) was 460 msec. A change in the water T1 from that of pure water was also observed in the experiments. PMID:19918888

  12. A General Approach to Error Estimation and Optimized Experiment Design, Applied to Multislice Imaging of T1in Human Brain at 4.1 T

    NASA Astrophysics Data System (ADS)

    Mason, Graeme F.; Chu, Wen-Jang; Hetherington, Hoby P.

    1997-05-01

    In this report, a procedure to optimize inversion-recovery times, in order to minimize the uncertainty in the measuredT1from 2-point multislice images of the human brain at 4.1 T, is discussed. The 2-point, 40-slice measurement employed inversion-recovery delays chosen based on the minimization of noise-based uncertainties. For comparison of the measuredT1values and uncertainties, 10-point, 3-slice measurements were also acquired. The measuredT1values using the 2-point method were 814, 1361, and 3386 ms for white matter, gray matter, and cerebral spinal fluid, respectively, in agreement with the respectiveT1values of 817, 1329, and 3320 ms obtained using the 10-point measurement. The 2-point, 40-slice method was used to determine theT1in the cortical gray matter, cerebellar gray matter, caudate nucleus, cerebral peduncle, globus pallidus, colliculus, lenticular nucleus, base of the pons, substantia nigra, thalamus, white matter, corpus callosum, and internal capsule.

  13. 40 CFR 721.10373 - 1H-Imidazole, 1-(1-methylethyl)-.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false 1H-Imidazole, 1-(1-methylethyl)-. 721... Substances § 721.10373 1H-Imidazole, 1-(1-methylethyl)-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as 1H-imidazole, 1-(1-methylethyl)- (PMN...

  14. 40 CFR 721.10373 - 1H-Imidazole, 1-(1-methylethyl)-.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false 1H-Imidazole, 1-(1-methylethyl)-. 721... Substances § 721.10373 1H-Imidazole, 1-(1-methylethyl)-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as 1H-imidazole, 1-(1-methylethyl)- (PMN...

  15. 40 CFR 721.10373 - 1H-Imidazole, 1-(1-methylethyl)-.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false 1H-Imidazole, 1-(1-methylethyl)-. 721... Substances § 721.10373 1H-Imidazole, 1-(1-methylethyl)-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as 1H-imidazole, 1-(1-methylethyl)- (PMN...

  16. 1H and 13C Solid-state NMR of Gossypium barbadense (Pima) Cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The interaction of water with cellulose and its influence on the nuclear spin dynamics in G. barbadense (Pima) cotton were investigated by 1H and 13C solid-state NMR techniques. 1H spin diffusion results from a Goldman-Shen experiment indicate that the water is multilayered. 1H MAS experiments pro...

  17. 1H and 13C Solid-state NMR of G. barbadense (Pima) Cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The interaction of water with cellulose and its influence on the nuclear spin dynamics in G. barbadense (Pima) cotton were investigated with 1H and 13C solid-state NMR techniques. 1H spin diffusion results from a Goldman-Shen experiment indicate that the water is multilayered. 1H MAS experiment...

  18. COPD Patients Have Short Lung Magnetic Resonance T1 Relaxation Time.

    PubMed

    Alamidi, Daniel F; Morgan, Alexandra R; Hubbard Cristinacce, Penny L; Nordenmark, Lars H; Hockings, Paul D; Lagerstrand, Kerstin M; Young, Simon S; Naish, Josephine H; Waterton, John C; Maguire, Niall C; Olsson, Lars E; Parker, Geoffrey J M

    2016-04-01

    Magnetic resonance imaging (MRI) may provide attractive biomarkers for assessment of pulmonary disease in clinical trials as it is free from ionizing radiation, minimally invasive and allows regional information. The aim of this study was to characterize lung MRI T1 relaxation time as a biomarker of chronic obstructive pulmonary disease (COPD); and specifically its relationship to smoking history, computed tomography (CT), and pulmonary function test (PFT) measurements in comparison to healthy age-matched controls. Lung T1 and inter-quartile range (IQR) of T1 maps from 24 COPD subjects and 12 healthy age-matched non-smokers were retrospectively analyzed from an institutional review board approved study. The subjects underwent PFTs and two separate MR imaging sessions at 1.5 tesla to test T1 repeatability. CT scans were performed on the COPD subjects. T1 repeatability (intraclass correlation coefficient) was 0.72 for repeated scans acquired on two visits. The lung T1 was significantly shorter (p < 0.0001) and T1 IQR was significantly larger (p = 0.0002) for the COPD subjects compared to healthy controls. Lung T1 significantly (p = 0.001) correlated with lung density assessed with CT. Strong significant correlations (p < 0.0001) between lung T1 and all PFT measurements were observed. Cigarette exposure did not correlate with lung T1 in COPD subjects. In conclusion, lung MRI T1 mapping shows potential as a repeatable, radiation free, non-invasive imaging technique in the evaluation of COPD. PMID:26488310

  19. The search for negative amplitude components in quasi-continuous distributions of relaxation times: the example of 1H magnetization exchange in articular cartilage and hydrated collagen

    NASA Astrophysics Data System (ADS)

    Fantazzini, Paola; Galassi, Francesca; Bortolotti, Villiam; Brown, Robert J. S.; Vittur, Franco

    2011-06-01

    When inverting nuclear magnetic resonance relaxation data in order to obtain quasi-continuous distributions of relaxation times for fluids in porous media, it is common practice to impose a non-negative (NN) constraint on the distributions. While this approach can be useful in reducing the effects of data distortion and/or preventing wild oscillations in the distributions, it may give misleading results in the presence of real negative amplitude components. Here, some examples of valid negative components for articular cartilage and hydrated collagen are given. Articular cartilage is a connective tissue, consisting mainly of collagen, proteoglycans and water, which can be considered, in many aspects, as a porous medium. Separate T1 relaxation data are obtained for low-mobility ('solid') macromolecular 1H and for higher-mobility ('liquid') 1H by the separation of these components in free induction decays, with α denoting the solid/liquid 1H ratio. When quasi-continuous distributions of relaxation times (T1) of the solid and liquid signal components of cartilage or collagen are computed from experimental relaxation data without imposing the usual NN constraint, valid negative peaks may appear. The features of the distributions, in particular negative peaks, and the fact that peaks at longer times for macromolecular and water protons are at essentially the same T1, are interpreted as the result of a magnetization exchange between these two spin pools. For the only-slightly-hydrated collagen samples, with α>1, the exchange leads to small negative peaks at short T1 times for the macromolecular component. However, for the cartilage, with substantial hydration or for a strongly hydrated collagen sample, both with αLt1, the behavior is reversed, with a negative peak for water at short times. The validity of a negative peak may be accepted (dismissed) by a high (low) cost of NN in error of fit. Computed distributions for simulated data using observed signal

  20. Characterization of Biochemical Cartilage Change After Anterior Cruciate Ligament Injury Using T1ρ Mapping Magnetic Resonance Imaging

    PubMed Central

    Osaki, Kanji; Okazaki, Ken; Takayama, Yukihisa; Matsubara, Hirokazu; Kuwashima, Umito; Murakami, Koji; Doi, Toshio; Matsuo, Yoshio; Honda, Hiroshi; Iwamoto, Yukihide

    2015-01-01

    Background: Patients with anterior cruciate ligament (ACL)–injured knees are at an increased risk of posttraumatic osteoarthritis (OA). OA changes secondary to ACL injuries have many variations, and when and where early cartilage degenerative change begins has not yet been established. Purpose: To characterize the location of cartilage degeneration after ACL injury associated with time since injury using T1rho (T1ρ) mapping. Study Design: Cross-sectional study; Level of evidence, 3. Methods: In this study, 49 knees with ACL injuries and 14 normal knees from uninjured volunteers were imaged with a 3.0-T magnetic resonance scanner. Three regions of interest (ROIs) were defined in the cartilage at the weightbearing area of the femoral condyles (anterior, middle, and posterior zones). Two ROIs were defined in the tibial plateau (anterior and posterior zones). The T1ρ values within the ROIs were measured. Patients were allocated into 3 groups based on time since injury: <12 weeks (group A; 28 patients), 12 weeks to 2 years (group B; 14 patients), and >2 years to 5 years (group C; 7 patients). Results: Mean T1ρ values were significantly greater in the anterior and middle ROIs of the medial femoral condyle in group C compared with those in other groups (P < .05). Patients with medial meniscus injury, for whom the time since injury was ≥12 weeks, exhibited significantly greater T1ρ values in the middle areas of the medial femoral condyle versus normal knees and ACL-injured knees without medial meniscus injury. Conclusion: The risk of cartilage degeneration in the area of the femoral condyle that contacts the tibia during small degrees of flexion increased when the time since injury was longer than 2 years. In addition, medial meniscus injury was associated with cartilage degeneration at the medial femoral condyle in the chronic phase. Clinical Relevance: Cartilage degeneration occurs more than 2 years after ACL injury and increases with medial meniscus injury

  1. Multislice T1 -prepared 2D single-shot EPI: analysis of a clinical T1 mapping method unbiased by B0 or B1 inhomogeneity.

    PubMed

    Lauzon, M Louis; McCreary, Cheryl R; Frayne, Richard

    2016-08-01

    Quantitative MR imaging is as sensitive in detecting lesions as qualitative imaging, but it is potentially more specific in differentiating disease. T1 mapping in particular might help to assess acute ischemic stroke, multiple sclerosis, epilepsy and Alzheimer's disease better. Thus, a rapid and robust clinical technique is vital. In 1990, Ordidge and colleagues developed the multislice T1 -prepared two-dimensional (2D) single-shot echo planar imaging technique. Subsequent studies demonstrated its clinical viability, but none performed an in-depth analysis of the strengths and advantages of this T1 mapping method. Herein, theoretical and experimental evidence shows that the technique accounts for 2D slice profile effects and is unbiased by B0 or B1 inhomogeneity. This is verified explicitly by varying the linear shims, the T1 preparation flip angle and the excitation flip angle. Furthermore, it is shown that the repetition time (and hence scan time) can be reduced without a loss of T1 accuracy. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27331861

  2. Synthesis, spectroscopic characterization, calculational studies and in vitro antitumoral activity of 4-(3-(1H-imidazol-1-yl)propyl)-(thiophen-2-ylmethyl)-1H-1,2,4-triazol-5(4H)-one

    NASA Astrophysics Data System (ADS)

    Süleymanoğlu, Nevin; Ustabaş, Reşat; Alpaslan, Yelda Bingöl; Ünver, Yasemin; Turan, Mustafa; Sancak, Kemal

    2011-03-01

    4-(3-(1H-imidazol-1-yl)propyl)-(thiophen-2-ylmethyl)-1H-1,2,4-triazol-5(4H)-one (IPTT), C 13H 15N 5OS, was synthesized and characterized by 13C NMR, 1H NMR, IR and single-crystal X-ray diffraction. The structure of IPTT is stabilized by three intermolecular hydrogen bonds and by intermolecular C sbnd H⋯ π interaction. The compound IPTT was modelled by using DFT method. Calculations of vibrational frequencies, gauge including atomic orbital (GIAO), 1H and 13C NMR chemical shifts of IPTT in the ground state, total electronic charge density map and frontier molecular orbitals were performed at B3LYP/6-31 G(d) level of theory were carried out by using DFT method with 6-31 G(d) basis set. The structural parameters obtained by geometry optimization, the theoretical vibrational frequencies and chemical shift values are in good agreement with experimental ones. FT-IR, NMR and X-ray analytical results of IPTT show that the compound exists as keto form, that was supported by DFT calculations. In addition, in vitro studies showed hopeful antitumoral activity of the title IPTT compound.

  3. Inhibition of Myeloperoxidase: Evaluation of 2H-Indazoles and 1H-Indazolones

    PubMed Central

    Roth, Aaron; Ott, Sean; Farber, Kelli M.; Palazzo, Teresa A.; Conrad, Wayne E.; Haddadin, Makhluf J.; Tantillo, Dean J.; Cross, Carroll E.; Eiserich, Jason P.; Kurth, Mark J.

    2014-01-01

    Myeloperoxidase (MPO) produces hypohalous acids as a key component of the innate immune response; however, release of these acids extracellularly results in inflammatory cell and tissue damage. The two-step, one-pot Davis-Beirut reaction was used to synthesize a library of 2H-indazoles and 1H-indazolones as putative inhibitors of MPO. A structure-activity relationship study was undertaken wherein compounds were evaluated utilizing taurine-chloramine and MPO-mediated H2O2 consumption assays. Docking studies as well as toxicophore and Lipinski analyses were performed. Fourteen compounds were found to be potent inhibitors with IC50 values <1 μM, suggesting these compounds could be considered as potential modulators of pro-oxidative tissue injury pertubated by the inflammatory MPO:H2O2:HOCl/HOBr system. PMID:25438766

  4. 1H-NMR study of the three low temperature phases of DPPC-water systems.

    PubMed

    Trahms, L; Klabe, W D; Boroske, E

    1983-06-01

    The three phases of dipalmitoylphosphatidylcholine-water dispersions, occurring below the main transition are studied by a moment analysis of 1H-nuclear magnetic resonance (NMR) spectra. The subtransition, recently detected by Chen, S. C., J. M. Sturtevant, and B. J. Gaffney, 1980, Pro. Natl. Acad. Sci. USA, 77:5060-5063, is characterized by a sharp drop in the second moment at 12 degrees C as a result of increasing the temperature. Interesting features of this phase transition are a hysteresis of 11 K and extremely slow kinetics. It is interpreted as the onset of a flip-flop of the hydrocarbon chains about their long axis. At the pretransition, this type of motion is assumed to change into a fast rotation. The proposed models for the three phases are confirmed by computer calculations of theoretical values for the second and fourth moments of the corresponding NMR signals. PMID:6688190

  5. Interaction of Daunomycin with Dipalmitoylphosphatidylcholine Model Membranes. A 1H NMR Study

    NASA Astrophysics Data System (ADS)

    Calzolai, Luigi; Gaggelli, Elena; Maccotta, Antonella; Valensin, Gianni

    1996-09-01

    1H NMR parameters were obtained for daunomycin in water solution in the free state as well as in the presence of dipalmitoylphosphatidylcholine model membranes. Spin-lattice relaxation rates were measured under nonselective, single-selective, and double-selective irradiation modes, and 2D NOESY spectra were obtained at several values of the mixing time. Proton-proton distances were calculated and the motional correlation time was evaluated in both the free and bound states. NMR parameters were used to show that ring A and the glucosamine moiety of daunomycin strongly interact with the external surface of the bilayer, while the rest of the molecule penetrates the membrane without crossing it. The structures of both free and bound daunomycin were obtained and compared by using molecular modeling.

  6. High-precision half-life measurements of the T =1 /2 mirror β decays 17F and 33Cl

    NASA Astrophysics Data System (ADS)

    Grinyer, J.; Grinyer, G. F.; Babo, M.; Bouzomita, H.; Chauveau, P.; Delahaye, P.; Dubois, M.; Frigot, R.; Jardin, P.; Leboucher, C.; Maunoury, L.; Seiffert, C.; Thomas, J. C.; Traykov, E.

    2015-10-01

    Background: Measurements of the f t values for T =1 /2 mirror β+ decays offer a method to test the conserved vector current hypothesis and to determine Vud, the up-down matrix element of the Cabibbo-Kobayashi-Maskawa matrix. In most mirror decays used for these tests, uncertainties in the f t values are dominated by the uncertainties in the half-lives. Purpose: Two precision half-life measurements were performed for the T =1 /2 β+ emitters, 17F and 33Cl, in order to eliminate the half-life as the leading source of uncertainty in their f t values. Method: Half-lives of 17F and 33Cl were determined using β counting of implanted radioactive ion beam samples on a moving tape transport system at the Système de Production d'Ions Radioactifs Accélérés en Ligne low-energy identification station at the Grand Accélérateur National d'Ions Lourds. Results: The 17F half-life result, 64.347 (35) s, precise to ±0.05 % , is a factor of 5 times more precise than the previous world average. The half-life of 33Cl was determined to be 2.5038 (22) s. The current precision of ±0.09 % is nearly 2 times more precise compared to the previous world average. Conclusions: The precision achieved during the present measurements implies that the half-life no longer dominates the uncertainty of the f t values for both T =1 /2 mirror decays 17F and 33Cl.

  7. Thermal degradation in a trimodal PDMS network by 1H Multiple Quantum NMR

    SciTech Connect

    Giuliani, J R; Gjersing, E L; Chinn, S C; Jones, T V; Wilson, T S; Alviso, C T; Herberg, J L; Pearson, M A; Maxwell, R S

    2007-06-06

    Thermal degradation of a filled, crosslinked siloxane material synthesized from PDMS chains of three different average molecular weights and with two different crosslinking species has been studied by {sup 1}H Multiple Quantum (MQ) NMR methods. Multiple domains of polymer chains were detected by MQ NMR exhibiting Residual Dipolar Coupling (<{Omega}{sub d}>) values of 200 Hz and 600 Hz, corresponding to chains with high average molecular weight between crosslinks and chains with low average molecular weight between crosslinks or near the multifunctional crosslinking sites. Characterization of the <{Omega}{sub d}> values and changes in <{Omega}{sub d}> distributions present in the material were studied as a function of time at 250 C and indicates significant time dependent degradation. For the domains with low <{Omega}{sub d}>, a broadening in the distribution was observed with aging time. For the domain with high <{Omega}{sub d}>, increases in both the mean <{Omega}{sub d}> and the width in <{Omega}{sub d}> were observed with increasing aging time. Isothermal Thermal Gravimetric Analysis (TGA) reveals a 3% decrease in weight over 20 hours of aging at 250 C. Degraded samples also were analyzed by traditional solid state {sup 1}H NMR techniques and offgassing products were identified by Solid Phase MicroExtraction followed by Gas Chromatography-Mass Spectrometry (SPME GC-MS). The results, which will be discussed here, suggest that thermal degradation proceeds by complex competition between oxidative chain scissioning and post-curing crosslinking that both contribute to embrittlement.

  8. Core/shell Fe3O4/Gd2O3 nanocubes as T1-T2 dual modal MRI contrast agents

    NASA Astrophysics Data System (ADS)

    Li, Fenfen; Zhi, Debo; Luo, Yufeng; Zhang, Jiqian; Nan, Xiang; Zhang, Yunjiao; Zhou, Wei; Qiu, Bensheng; Wen, Longping; Liang, Gaolin

    2016-06-01

    T1-T2 dual modal magnetic resonance imaging (MRI) has attracted considerable interest because it offers complementary diagnostic information, leading to more precise diagnosis. To date, a number of nanostructures have been reported as T1-T2 dual modal MR contrast agents (CAs). However, hybrids of nanocubes with both iron and gadolinium (Gd) elements as T1-T2 dual modal CAs have not been reported. Herein, we report the synthesis of novel core/shell Fe3O4/Gd2O3 nanocubes as T1-T2 dual-modal CAs and their application for enhanced T1-T2 MR imaging of rat livers. A relaxivity study at 1.5 T indicated that our Fe3O4/Gd2O3 nanocubes have an r1 value of 45.24 mM-1 s-1 and an r2 value of 186.51 mM-1 s-1, which were about two folds of those of Gd2O3 nanoparticles and Fe3O4 nanocubes, respectively. In vivo MR imaging of rats showed both T1-positive and T2-negative contrast enhancements in the livers. We envision that our Fe3O4/Gd2O3 nanocubes could be applied as T1-T2 dual modal MR CAs for a wide range of theranostic applications in the near future.T1-T2 dual modal magnetic resonance imaging (MRI) has attracted considerable interest because it offers complementary diagnostic information, leading to more precise diagnosis. To date, a number of nanostructures have been reported as T1-T2 dual modal MR contrast agents (CAs). However, hybrids of nanocubes with both iron and gadolinium (Gd) elements as T1-T2 dual modal CAs have not been reported. Herein, we report the synthesis of novel core/shell Fe3O4/Gd2O3 nanocubes as T1-T2 dual-modal CAs and their application for enhanced T1-T2 MR imaging of rat livers. A relaxivity study at 1.5 T indicated that our Fe3O4/Gd2O3 nanocubes have an r1 value of 45.24 mM-1 s-1 and an r2 value of 186.51 mM-1 s-1, which were about two folds of those of Gd2O3 nanoparticles and Fe3O4 nanocubes, respectively. In vivo MR imaging of rats showed both T1-positive and T2-negative contrast enhancements in the livers. We envision that our Fe3O4/Gd2O3 nanocubes

  9. Seroreactivity against Specific L5P Antigen from Mycobacterium avium subsp. paratuberculosis in Children at Risk for T1D

    PubMed Central

    Niegowska, Magdalena; Rapini, Novella; Biet, Frank; Piccinini, Simona; Bay, Sylvie; Lidano, Roberta; Manca Bitti, Maria Luisa; Sechi, Leonardo A.

    2016-01-01

    Aims/Hypothesis Although numerous environmental agents have been investigated over the years as possible triggers of type 1 diabetes (T1D), its causes remain unclear. We have already demonstrated an increased prevalence of antibodies against peptides derived from Mycobacterium avuim subsp. paratuberculosis (MAP) homologous to human zinc transporter 8 protein (ZnT8) and proinsulin in Italian subjects at risk for or affected by T1D. In this study, we compared titers of the previously detected antibodies with seroreactivity to MAP lipopentapetide (L5P) that recently emerged as a strong immunogenic component able to specifically distinguish MAP from other mycobacteria. Methods Plasma of 32 children and youth at risk for T1D including follow-up samples and 42 age-matched healthy controls (HC) recruited at the Tor Vergata University Hospital in Rome was analyzed by indirect ELISA for the presence of antibodies against MAP-derived epitopes MAP3865c133–141, MAP3865c125-133, MAP2404c70-85 and MAP1,4αgbp157-173 along with their ZnT8 and proinsulin homologs. The data were analyzed through two-tailed Mann-Whitney U test and relation between variables was determined by principal component analysis. Results Responses to L5P were not detectable in subjects whose initial seroreactivity to MAP peptides and their human homologs was lost in follow-up samples, whereas anti-L5P antibodies appeared constantly in individuals with a stable immunity against MAP antigens. The overall coincidence in positivity to L5P and the four MAP epitopes both in children at risk for T1D and HC exceeded 90%. Conclusions MAP-derived homologs may cross-react with ZnT8 and proinsulin peptides inducing immune responses at a young age in subjects predisposed for T1D. Thus, L5P may have a diagnostic value to immediately indicate the presence of anti-MAP seroreactivity when evaluation of a more complex antibody status is not required. Almost complete coincidence in responses to both types of antigens lends

  10. MRI and (1)H MRS findings of hepatobilary changes and cholangiocarcinoma development in hamsters infected with Opisthorchis viverrini and treated with N-nitrosodimethylamine.

    PubMed

    Hanpanich, Petcharakorn; Pinlaor, Somchai; Charoensuk, Lakhanawan; Yongvanit, Puangrat; Chamgramol, Yaovalux; Pairojkul, Chawalit; Mairiang, Eimorn

    2015-11-01

    3 T MRI and (1)H MRS were useful for quantitative investigation of the serial development of hepatobiliary changes in Opisthorchis viverrini infection in hamsters, and the differential diagnosis of cholangiocacinoma (CCA) development from bile duct changes and normal condition is unclear. In this study, we investigated the serial development of hepatobiliary changes and CCAgenesis in O. viverrini-infected and N-nitrosodimethylamine (NDMA) treated hamsters (ON group) using 3 T MRI and (1)H MRS and the results were compared with those either in the O. viverrini-infected group (OV group) and uninfected normal controls. In the ON group, CCAs were first found at 9 weeks post-infection, with sizes of ~2 mm. The typical MR signal characteristics of CCA were hypo- and occasionally isointensity signal on T1-weighted images, and mild-moderate to hyper-intensity signal on T2-weighted images compared to the liver parenchyma. T2-weighted images with fat suppression revealed dilatation of the intra- and extrahepatic bile ducts, and often defined the anatomical level of biliary obstruction, cystic lesions, liver abscesses, and CCA which was starting seen of these noticeable abnormalities at 5 weeks onwards. The results of fibrosis grading using MR images showed a positive correlation (r=0.90, P<0.038 by Spearman's rank correlation test) with those of the histopathological grading. In addition, 3.0 T (1)H MRS showed elevated choline and decreased lipids levels in the liver tissues of the ON group. In conclusion, MRI and (1)H MRS are useful for the quantitative investigation of the serial development of hepatobilary changes and CCA in hamsters, and are potentially useful as early diagnostic tools for CCA. PMID:26117689

  11. Strain-dependent T1 Relaxation Profiles in Articular Cartilage by MRI at Microscopic Resolutions

    PubMed Central

    Xia, Yang; Wang, Nian; Lee, Jihyun; Badar, Farid

    2011-01-01

    To investigate the dependency of T1 relaxation on mechanical strain in articular cartilage, quantitative MRI T1 imaging experiments were carried out on cartilage before/after the tissue was immersed in gadolinium contrast agent and when the tissue was being compressed (up to ~ 48% strains). The spatial resolution across the cartilage depth was 17.6μm. The T1 profile in native tissue (without the presence of gadolinium ions) was strongly strain-dependent, which is also depth-dependent. At the modest strains (e.g., 14% strain), T1 reduced by up to 68% in the most surface portion of the tissue. Further compression (e.g., 45% strain) reduced T1 mostly in the middle and deep portions of the tissue. For the gadolinium-immersed tissue, both modest and heavy compressions (up to 48% strain) increased T1 slightly but significantly, although the overall shapes of the T1 profiles remained approximately the same regardless of the amount of strains. The complex relationships between the T1 profiles and the mechanical strains were a direct consequence of the depth-dependent proteoglycan concentration in the tissue, which determined the tissue’s mechanical properties. This finding has potential implications in the use of gadolinium contrast agent in clinical MRI of cartilage (the dGEMRIC procedure), when the loading or loading history of patients is considered. PMID:21452280

  12. Quantitative evaluation of the lactate signal loss and its spatial dependence in press localized (1)H NMR spectroscopy.

    PubMed

    Jung, W I; Bunse, M; Lutz, O

    2001-10-01

    Localized (1)H NMR spectroscopy using the 90 degrees -t(1)-180 degrees -t(1)+t(2)-180 degrees -t(2)-Acq. PRESS sequence can lead to a signal loss for the lactate doublet compared with signals from uncoupled nuclei which is dependent on the choice of t(1) and t(2). The most striking signal loss of up to 78% of the total signal occurs with the symmetrical PRESS sequence (t(1)=t(2)) at an echo time of 2/J (approximately 290 ms). Calculations have shown that this signal loss is related to the pulse angle distributions produced by the two refocusing pulses which leads to the creation of single quantum polarization transfer (PT) as well as to not directly observable states (NDOS) of the lactate AX(3) spin system: zero- and multiple-quantum coherences, and longitudinal spin orders. In addition, the chemical shift dependent voxel displacement (VOD) leads to further signal loss. By calculating the density operator for various of the echo times TE=n/J, n=1, 2, 3,..., we calculated quantitatively the contributions of these effects to the signal loss as well as their spatial distribution. A maximum signal loss of 75% can be expected from theory for the symmetrical PRESS sequence and TE=2/J for Hamming filtered sinc pulses, whereby 47% are due to the creation of NDOS and up to 28% arise from PT. Taking also the VOD effect into account (2 mT/m slice selection gradients, 20-mm slices) leads to 54% signal loss from NDOS and up to 24% from PT, leading to a maximum signal loss of 78%. Using RE-BURP pulses with their more rectangular pulse angle distributions reduces the maximum signal loss to 44%. Experiments at 1.5 T using a lactate solution demonstrated a maximum lactate signal loss for sinc pulses of 82% (52% NDOS, 30% PT) at TE=290 ms using the symmetrical PRESS sequence. The great signal loss and its spatial distribution is of importance for investigations using a symmetrical PRESS sequence at TE=2/J. PMID:11567573

  13. Quantitative Evaluation of the Lactate Signal Loss and Its Spatial Dependence in PRESS Localized 1H NMR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Jung, Wulf-Ingo; Bunse, Michael; Lutz, Otto

    2001-10-01

    Localized 1H NMR spectroscopy using the 90°-t1-180°-t1+t2-180°-t2-Acq. PRESS sequence can lead to a signal loss for the lactate doublet compared with signals from uncoupled nuclei which is dependent on the choice of t1 and t2. The most striking signal loss of up to 78% of the total signal occurs with the symmetrical PRESS sequence (t1=t2) at an echo time of 2/J (≃290 ms). Calculations have shown that this signal loss is related to the pulse angle distributions produced by the two refocusing pulses which leads to the creation of single quantum polarization transfer (PT) as well as to not directly observable states (NDOS) of the lactate AX3 spin system: zero- and multiple-quantum coherences, and longitudinal spin orders. In addition, the chemical shift dependent voxel displacement (VOD) leads to further signal loss. By calculating the density operator for various of the echo times TE=n/J, n=1, 2, 3, …, we calculated quantitatively the contributions of these effects to the signal loss as well as their spatial distribution. A maximum signal loss of 75% can be expected from theory for the symmetrical PRESS sequence and TE=2/J for Hamming filtered sinc pulses, whereby 47% are due to the creation of NDOS and up to 28% arise from PT. Taking also the VOD effect into account (2 mT/m slice selection gradients, 20-mm slices) leads to 54% signal loss from NDOS and up to 24% from PT, leading to a maximum signal loss of 78%. Using RE-BURP pulses with their more rectangular pulse angle distributions reduces the maximum signal loss to 44%. Experiments at 1.5 T using a lactate solution demonstrated a maximum lactate signal loss for sinc pulses of 82% (52% NDOS, 30% PT) at TE=290 ms using the symmetrical PRESS sequence. The great signal loss and its spatial distribution is of importance for investigations using a symmetrical PRESS sequence at TE=2/J.

  14. Loss of PiT-1 Results in Abnormal Endocytosis in the Yolk Sac Visceral Endoderm

    PubMed Central

    Wallingford, Mary C.; Giachelli, Cecilia M.

    2014-01-01

    PiT-1 protein is a transmembrane sodium-dependent phosphate (Pi) transporter. PiT-1 knock out (KO) embryos die from largely unknown causes by embryonic day (E) 12.5. We tested the hypothesis that PiT-1 is required for endocytosis in the embryonic yolk sac (YS) visceral endoderm (VE). Here we present data supporting that PiT-1 KO results in a YS remodeling defect and decreased endocytosis in the YS VE. The remodeling defect is not due to an upstream cardiomyocyte requirement for PiT-1, as SM22αCre-specific KO of PiT-1 in the developing heart and the YS mesodermal layer (ME) does not recapitulate the PiT-1 global KO phenotype. Furthermore, we find that high levels of PiT-1 protein localize to the YS VE apical membrane. Together these data support that PiT-1 is likely required in YS VE. During normal development maternal immunoglobulin (IgG) is endocytosed into YS VE and accumulates in the apical side of the VE in a specialized lysosome termed the apical vacuole (AV). We have identified a reduction in PiT-1 KO VE cell height and a striking loss of IgG accumulation in the PiT-1 KO VE. The endocytosis genes Tfeb, Lamtor2 and Snx2 are increased at the RNA level. Lysotracker Red staining reveals a loss of distinct AVs, and yolk sacs incubated ex vivo with phRODO Green Dextran for Endocytosis demonstrate a functional loss of endocytosis. As yolk sac endocytosis is controlled in part by microautophagy, but expression of LC3 had not been examined, we investigated LC3 expression during yolk sac development and found stage-specific LC3 RNA expression that is predominantly from the YS VE layer at E9.5. Normalized LC3-II protein levels are decreased in the PiT-1 KO YS, supporting a requirement for PiT-1 in autophagy in the YS. Therefore, we propose the novel idea that PiT-1 is central to the regulation of endocytosis and autophagy in the YS VE. PMID:25138534

  15. Understanding 2H/1H systematics of leaf wax n-alkanes in coastal plants at Stiffkey saltmarsh, Norfolk, UK

    NASA Astrophysics Data System (ADS)

    Eley, Yvette; Dawson, Lorna; Black, Stuart; Andrews, Julian; Pedentchouk, Nikolai

    2014-03-01

    Interpretation of sedimentary n-alkyl lipid δ2H data is complicated by a limited understanding of factors controlling interspecies variation in biomarker 2H/1H composition. To distinguish between the effects of interrelated environmental, physical and biochemical controls on the hydrogen isotope composition of n-alkyl lipids, we conducted linked δ2H analyses of soil water, xylem water, leaf water and n-alkanes from a range of C3 and C4 plants growing at a UK saltmarsh (i) across multiple sampling sites, (ii) throughout the 2012 growing season, and (iii) at different times of the day. Soil waters varied isotopically by up to 35‰ depending on marsh sub-environment, and exhibited site-specific seasonal shifts in δ2H up to a maximum of 31‰. Maximum interspecies variation in xylem water was 38‰, while leaf waters differed seasonally by a maximum of 29‰. Leaf wax n-alkane 2H/1H, however, consistently varied by over 100‰ throughout the 2012 growing season, resulting in an interspecies range in the ɛwax/leaf water values of -79‰ to -227‰. From the discrepancy in the magnitude of these isotopic differences, we conclude that mechanisms driving variation in the 2H/1H composition of leaf water, including (i) spatial changes in soil water 2H/1H, (ii) temporal changes in soil water 2H/1H, (iii) differences in xylem water 2H/1H, and (iv) differences in leaf water evaporative 2H-enrichment due to varied plant life forms, cannot explain the range of n-alkane δ2H values we observed. Results from this study suggests that accurate reconstructions of palaeoclimate regimes from sedimentary n-alkane δ2H require further research to constrain those biological mechanisms influencing species-specific differences in 2H/1H fractionation during lipid biosynthesis, in particular where plants have developed biochemical adaptations to water-stressed conditions. Understanding how these mechanisms interact with environmental conditions will be crucial to ensure accurate

  16. In vivo relaxation time measurements on a murine tumor model--prolongation of T1 after photodynamic therapy.

    PubMed

    Liu, Y H; Hawk, R M; Ramaprasad, S

    1995-01-01

    RIF tumors implanted on mice feet were investigated for changes in relaxation times (T1 and T2) after photodynamic therapy (PDT). Photodynamic therapy was performed using Photofrin II as the photosensitizer and laser light at 630 nm. A home-built proton solenoid coil in the balanced configuration was used to accommodate the tumors, and the relaxation times were measured before, immediately after, and up to several hours after therapy. Several control experiments were performed untreated tumors, tumors treated with Photofrin II alone, or tumors treated with laser light alone. Significant increases in T1s of water protons were observed after PDT treatment. In all experiments, 31P spectra were recorded before and after the therapy to study the tumor status and to confirm the onset of PDT. These studies show significant prolongation of T1s after the PDT treatment. The spin-spin relaxation measurements, on the other hand, did not show such prolongation in T2 values after PDT treatment. PMID:7739367

  17. Dispersion of T1 and T2 nuclear magnetic resonance relaxation in crude oils.

    PubMed

    Chen, Joseph J; Hürlimann, Martin; Paulsen, Jeffrey; Freed, Denise; Mandal, Soumyajit; Song, Yi-Qiao

    2014-09-15

    Crude oils, which are complex mixtures of hydrocarbons, can be characterized by nuclear magnetic resonance diffusion and relaxation methods to yield physical properties and chemical compositions. In particular, the field dependence, or dispersion, of T1 relaxation can be used to investigate the presence and dynamics of asphaltenes, the large molecules primarily responsible for the high viscosity in heavy crudes. However, the T2 relaxation dispersion of crude oils, which provides additional insight when measured alongside T1, has yet to be investigated systematically. Here we present the field dependence of T1-T2 correlations of several crude oils with disparate densities. While asphaltene and resin-containing crude oils exhibit significant T1 dispersion, minimal T2 dispersion is seen in all oils. This contrasting behavior between T1 and T2 cannot result from random molecular motions, and thus, we attribute our dispersion results to highly correlated molecular dynamics in asphaltene-containing crude oils. PMID:24919743

  18. Cavity Ringdown Absorption Spectrum of the T_1 (n,π^{*}) ← S_0 Transition of 2-CYCLOHEXEN-1-ONE

    NASA Astrophysics Data System (ADS)

    Zabronsky, Katherine L.; McAnally, Michael O.; Stupca, Daniel J.; Pillsbury, Nathan R.; Drucker, Stephen

    2013-06-01

    The cavity ringdown (CRD) absorption spectrum of 2-cyclohexen-1-one (CHO) was recorded over the range 401.5-410.5 nm in a room-temperature gas cell. The very weak band system (ɛ ≤ 0.02 dm^3 mol^{-1} {cm}^{-1}) in this region is due to the T_1(n, π*) ← S_0 electronic transition. The 0^0_0 origin band was assigned to the feature observed at {24,558.6 ± 0.3 {cm}^{-1}}. We have assigned about 25 vibronic transitions in a region extending from {-200 to +350 cm^{-1}} relative to the origin band. From these assignments we determined fundamental frequencies for several vibrational modes in the T_1 excited state. The table below compares their frequencies to corresponding values measured for CHO vapor in the S_0 electronic ground state (via far-IR spectroscopy) and the S_1(n, π*) excited state (via near-UV CRD spectroscopy). Low-frequency fundamentals (cm^{-1}) of CHO vapor Mode Description S_0 S_1(n,π^*) T_1(n,π^*) 39 ring twist 99.2 122.1 99.5 38 bend (inversion of C-5) 247 251.9 253.2 37 C=C twist 304.1 303.3 247.8 36 C=O wag 485 343.9 345.5 For ν_{39} and ν_{37}, the differences between S_1 and T_1 frequencies are noteworthy. These differences suggest that the electron delocalization associated with the π^* ← n chromophore in CHO is substantially different for singlet vs. triplet excitation. T. L. Smithson and H. Wieser, J. Chem. Phys. {73}, 2518 (1980) M. Z. M. Rishard and J. Laane, J. Molec. Struct. {976}, 56 (2010). M. Z. M. Rishard, E. A. Brown, L. K. Ausman, S. Drucker and J. Laane, J. Phys. Chem. A {112}, 38 (2008).

  19. Probing the influential factors of NMR T1-T2 spectra in the characterization of the kerogen by numerical simulation.

    PubMed

    Ge, Xinmin; Fan, Yiren; Chen, Hua; Deng, Shaogui; Cao, Yingchang; Zahid, Muhammad Aleem

    2015-11-01

    The low field nuclear magnetic resonance (NMR) spectroscopy has been widely used to characterize the longitudinal and transversal relaxation (T1-T2) spectrum of unconventional resources such as shale gas and tight oil containing significant proportions of kerogen and bitumen. However, it requires exquisite design of the acquisition model and the inversion algorithm due to the fast relaxation nature of the kerogen and bitumen. A new direct two dimensional (2D) inversion algorithm combined the iterative truncated singular value decomposition (TSVD) and the Akaiake Information Criterion (AIC) is presented to perform the data inversion efficiently. The fluid component decomposition (FCD) is applied to construct the forward T1-T2 model of the kerogen, and numerical simulations are conducted to investigate factors which may influence inversion results including echo spacing, recovery time series, signal to noise ratio (SNR), and the maximal iteration time. Results show that the T2 component is heavily impaired by the echo spacing, whereas the T1 component is influenced by the recovery time series but with limited effects. The inversion precision is greatly affected by the quality of the data. The inversed spectrum deviates from the model seriously when the SNR of the artificial noise is lower than 50, and the T2 component is more sensitive to the noise than the T1 component. What's more, the maximal iteration time can also affect the inversion result, especially when the maximal iteration time is smaller than 500. Proper acquisition and inversion parameters for the characterization of the kerogen are obtained considering the precision and the computational cost. PMID:26397220

  20. Probing the influential factors of NMR T1-T2 spectra in the characterization of the kerogen by numerical simulation

    NASA Astrophysics Data System (ADS)

    Ge, Xinmin; Fan, Yiren; Chen, Hua; Deng, Shaogui; Cao, Yingchang; Zahid, Muhammad Aleem

    2015-11-01

    The low field nuclear magnetic resonance (NMR) spectroscopy has been widely used to characterize the longitudinal and transversal relaxation (T1-T2) spectrum of unconventional resources such as shale gas and tight oil containing significant proportions of kerogen and bitumen. However, it requires exquisite design of the acquisition model and the inversion algorithm due to the fast relaxation nature of the kerogen and bitumen. A new direct two dimensional (2D) inversion algorithm combined the iterative truncated singular value decomposition (TSVD) and the Akaiake Information Criterion (AIC) is presented to perform the data inversion efficiently. The fluid component decomposition (FCD) is applied to construct the forward T1-T2 model of the kerogen, and numerical simulations are conducted to investigate factors which may influence inversion results including echo spacing, recovery time series, signal to noise ratio (SNR), and the maximal iteration time. Results show that the T2 component is heavily impaired by the echo spacing, whereas the T1 component is influenced by the recovery time series but with limited effects. The inversion precision is greatly affected by the quality of the data. The inversed spectrum deviates from the model seriously when the SNR of the artificial noise is lower than 50, and the T2 component is more sensitive to the noise than the T1 component. What's more, the maximal iteration time can also affect the inversion result, especially when the maximal iteration time is smaller than 500. Proper acquisition and inversion parameters for the characterization of the kerogen are obtained considering the precision and the computational cost.

  1. Combined Analysis of Stable Isotope, (1)H NMR, and Fatty Acid To Verify Sesame Oil Authenticity.

    PubMed

    Kim, Jeongeun; Jin, Gyungsu; Lee, Yunhee; Chun, Hyang Sook; Ahn, Sangdoo; Kim, Byung Hee

    2015-10-14

    The aim of this study was to verify the authenticity of sesame oils using combined analysis of stable isotope ratio, (1)H NMR spectroscopy, and fatty acid profiles of the oils. Analytical data were obtained from 35 samples of authentic sesame oils and 29 samples of adulterated sesame oils currently distributed in Korea. The orthogonal projection to latent structure discriminant analysis technique was used to select variables that most effectively verify the sesame oil authenticity. The variables include δ(13)C value, integration values of NMR peaks that signify the CH3 of n-3 fatty acids, CH2 between two C═C, protons from sesamin/sesamolin, and 18:1n-9, 18:3n-3, 18:2t, and 18:3t content values. The authenticity of 65 of 70 blind samples was correctly verified by applying the range of the eight variables found in the authentic sesame oil samples, suggesting that triple analysis is a useful approach to verify sesame oil authenticity. PMID:26395416

  2. Do Cartilage Repair Procedures Prevent Degenerative Meniscus Changes? Longitudinal T1ρ and Morphological Evaluation at 3.0T

    PubMed Central

    Jungmann, Pia M.; Li, Xiaojuan; Nardo, Lorenzo; Subburaj, Karupppasamy; Lin, Wilson; Ma, C. Benjamin; Majumdar, Sharmila; Link, Thomas M.

    2014-01-01

    Background Cartilage repair (CR) procedures are widely accepted for treatment of isolated cartilage defects at the knee joint. However, it is not well known whether these procedures prevent degenerative joint disease. Hypothesis/Purpose CR procedures prevent accelerated qualitative and quantitative progression of meniscus degeneration in individuals with focal cartilage defects. Study Design Cohort Study; Level of evidence 2b Methods A total of 94 subjects were studied. CR procedures were performed on 34 patients (n=16 osteochondral transplantation, n=18 microfracture); 34 controls were matched. An additional 13 patients received CR and anterior cruciate ligament (ACL) reconstruction (CR&ACL) and 13 patients received only ACL reconstruction. 3.0T MRI with T1ρ mapping and sagittal fat-saturated intermediate-weighted fast spin echo (FSE) sequences was performed to analyze menisci quantitatively and qualitatively (Whole-Organ Magnetic Resonance Imaging Score, WORMS). CR and CR&ACL patients were examined 4 months (n=34; n=13), 1 (n=21; n=8) and 2 (n=9; n=5) years post CR. Control subjects were scanned at baseline and after 1 and 2 years, ACL patients after 1 and 2 years. Results At baseline, global meniscus T1ρ values were higher in individuals with CR (14.2±0.6ms; P=0.004) and in individuals with CR&ACL (17.1±0.9ms; P<0.001) when compared to controls (12.8±0.6ms). After two years, there was a statistical difference between T1ρ at the overlying meniscus above cartilage defects (16.4±1.0ms) and T1ρ of the subgroup of control knees without cartilage defects (12.1±0.8ms; P<0.001) and a statistical trend to the CR group (13.3±1.0 ms; P=0.088). At baseline, 35% of subjects with CR showed morphological meniscus tears at the overlying meniscus; 10% of CR subjects showed an increase of WORMS meniscus score within the first year, none progressed in the second year. Control subjects with (without) cartilage defects showed meniscus tears in 30% (5%) at baseline; 38% (19

  3. Origin and Spread of Bos taurus: New Clues from Mitochondrial Genomes Belonging to Haplogroup T1

    PubMed Central

    Bonfiglio, Silvia; Ginja, Catarina; De Gaetano, Anna; Achilli, Alessandro; Olivieri, Anna; Colli, Licia; Tesfaye, Kassahun; Agha, Saif Hassan; Gama, Luis T.; Cattonaro, Federica; Penedo, M. Cecilia T; Ajmone-Marsan, Paolo; Torroni, Antonio; Ferretti, Luca

    2012-01-01

    Background Most genetic studies on modern cattle have established a common origin for all taurine breeds in the Near East, during the Neolithic transition about 10 thousand years (ka) ago. Yet, the possibility of independent and/or secondary domestication events is still debated and is fostered by the finding of rare mitochondrial DNA (mtDNA) haplogroups like P, Q and R. Haplogroup T1, because of its geographic distribution, has been the subject of several investigations pointing to a possible independent domestication event in Africa and suggesting a genetic contribution of African cattle to the formation of Iberian and Creole cattle. Whole mitochondrial genome sequence analysis, with its proven effectiveness in improving the resolution of phylogeographic studies, is the most appropriate tool to investigate the origin and structure of haplogroup T1. Methodology A survey of >2200 bovine mtDNA control regions representing 28 breeds (15 European, 10 African, 3 American) identified 281 subjects belonging to haplogroup T1. Fifty-four were selected for whole mtDNA genome sequencing, and combined with ten T1 complete sequences from previous studies into the most detailed T1 phylogenetic tree available to date. Conclusions Phylogenetic analysis of the 64 T1 mitochondrial complete genomes revealed six distinct sub-haplogroups (T1a–T1f). Our data support the overall scenario of a Near Eastern origin of the T1 sub-haplogroups from as much as eight founding T1 haplotypes. However, the possibility that one sub-haplogroup (T1d) arose in North Africa, in domesticated stocks, shortly after their arrival from the Near East, can not be ruled out. Finally, the previously identified “African-derived American" (AA) haplotype turned out to be a sub-clade of T1c (T1c1a1). This haplotype was found here for the first time in Africa (Egypt), indicating that it probably originated in North Africa, reached the Iberian Peninsula and sailed to America, with the first European settlers

  4. Equilibrium 2H/1H fractionation in organic molecules: III. Cyclic ketones and hydrocarbons

    NASA Astrophysics Data System (ADS)

    Wang, Ying; Sessions, Alex L.; Nielsen, Robert J.; Goddard, William A.

    2013-04-01

    Quantitative interpretation of stable hydrogen isotope ratios (2H/1H) in organic compounds is greatly aided by knowledge of the relevant equilibrium fractionation factors (ɛeq). Previous efforts have combined experimental measurements and hybrid Density Functional Theory (DFT) calculations to accurately predict equilibrium fractionations in linear (acyclic) organic molecules (Wang et al., 2009a,b), but the calibration produced by that study is not applicable to cyclic compounds. Here we report experimental measurements of equilibrium 2H/1H fractionation in six cyclic ketones, and use those data to evaluate DFT calculations of fractionation in diverse monocyclic and polycyclic compounds commonly found in sedimentary organic matter and petroleum. At 25, 50, and 75 °C, the experimentally measured ɛeq values for secondary and tertiary Hα in isotopic equilibrium with water are in the ranges of -130‰ to -150‰ and +10‰ to -40‰ respectively. Measured data are similar to DFT calculations of ɛeq for axial Hα but not equatorial Hα. In tertiary Cα positions with methyl substituents, this can be understood as a result of the methyl group forcing Hα atoms into a dominantly axial position. For secondary Cα positions containing both axial and equatorial Hα atoms, we propose that axial Hα exchanges with water significantly faster than the equatorial Hα does, due to the hyperconjugation-stabilized transition state. Interconversion of axial and equatorial positions via ring flipping is much faster than isotopic exchange at either position, and as a result the steady-state isotopic composition of both H's is strongly weighted toward that of axial Hα. Based on comparison with measured ɛeq values, a total uncertainty of 10-30‰ remains for theoretical ɛeq values. Using DFT, we systematically estimated the ɛeq values for individual H positions in various cyclic structures. By summing over all individual H positions, the molecular equilibrium fractionation was

  5. Numerical simulation of ( T 2, T 1) 2D NMR and fluid responses

    NASA Astrophysics Data System (ADS)

    Tan, Mao-Jin; Zou, You-Long; Zhang, Jin-Yan; Zhao, Xin

    2012-12-01

    One-dimensional nuclear magnetic resonance (1D NMR) logging technology is limited for fluid typing, while two-dimensional nuclear magnetic resonance (2D NMR) logging can provide more parameters including longitudinal relaxation time ( T 1) and transverse relaxation time ( T 2) relative to fluid types in porous media. Based on the 2D NMR relaxation mechanism in a gradient magnetic field, echo train simulation and 2D NMR inversion are discussed in detail. For 2D NMR inversion, a hybrid inversion method is proposed based on the damping least squares method (LSQR) and an improved truncated singular value decomposition (TSVD) algorithm. A series of spin echoes are first simulated with multiple waiting times ( T W s) in a gradient magnetic field for given fluid models and these synthesized echo trains are inverted by the hybrid method. The inversion results are consistent with given models. Moreover, the numerical simulation of various fluid models such as the gas-water, light oil-water, and vicious oil-water models were carried out with different echo spacings ( T E s) and T W s by this hybrid method. Finally, the influences of different signal-to-noise ratios (SNRs) on inversion results in various fluid models are studied. The numerical simulations show that the hybrid method and optimized observation parameters are applicable to fluid typing of gas-water and oil-water models.

  6. Metallothionein 1 h tumour suppressor activity in prostate cancer is mediated by euchromatin methyltransferase 1

    PubMed Central

    Han, Yu-Chen; Zheng, Zhong-Liang; Zuo, Ze-Hua; Yu, Yan P; Chen, Rui; Tseng, George C; Nelson, Joel B; Luo, Jian-Hua

    2014-01-01

    Metallothioneins (MTs) are a group of metal binding proteins thought to play a role in the detoxification of heavy metals. Here we showed by microarray and validation analyses that MT1h, a member of MT, is down-regulated in many human malignancies. Low expression of MT1h was associated with poor clinical outcomes in both prostate and liver cancer. We found that the promoter region of MT1h was hypermethylated in cancer and that demethylation of the MT1h promoter reversed the suppression of MT1h expression. Forced expression of MT1h induced cell growth arrest, suppressed colony formation, retarded migration, and reduced invasion. SCID mice with tumour xenografts with inducible MT1h expression had lower tumour volumes as well as fewer metastases and deaths than uninduced controls. MT1h was found to interact with euchromatin histone methyltransferase 1 (EHMT1) and enhanced its methyltransferase activity on histone 3. Knocking down of EHMT1 or a mutation in MT1h that abrogates its interaction with EHMT1 abrogated MT1h tumour suppressor activity. This demonstrates tumour suppressor activity in a heavy metal binding protein that is dependent on activation of histone methylation. PMID:23355073

  7. Single-shot diffusion trace (1)H NMR spectroscopy.

    PubMed

    de Graaf, R A; Braun, K P; Nicolay, K

    2001-05-01

    Ignoring diffusion anisotropy can severely hamper the quantitative determination of water and metabolite diffusion in complex tissues. The measurement of the trace of the diffusion tensor provides unambiguous and rotationally invariant ADC values, but usually requires three separate experiments. A single-shot technique developed earlier, originally designed for diffusion trace MR imaging (Mori and van Zijl, Magn Reson Med 1995;33:41-52), was improved and adapted for diffusion trace MR spectroscopy. A double spin-echo pulse sequence was incorporated with four pairs of bipolar gradients with specific predetermined relative signs in each of the three orthogonal directions. The combination of gradient directions leads to cancellation of all off-diagonal tensor elements while constructively adding the diagonal elements. Furthermore, the pulse scheme provides complete compensation for cross-terms between static magnetic field gradients and the applied diffusion gradients, while simultaneously avoiding cross-terms with localization gradients. The sequence was tested at 4.7 T in vivo on rat brain for MRI and on rat skeletal muscle and brain for MRS. It is shown that the average ADC as determined from the measurement of the ADCs in the three orthogonal directions is in close agreement with the ADC obtained along the trace of the diffusion tensor in a single acquisition, for both water and metabolite diffusion. The large differences in water and metabolite diffusion coefficients as measured in the individual orthogonal directions illustrate the need for diffusion trace measurements when accurate and rotationally invariant diffusion quantitation is required. The pulse scheme presented here may be applied for such purposes in MRS and MRI studies. PMID:11323799

  8. Dynamic Quantitative T1 Mapping in Orthotopic Brain Tumor Xenografts1

    PubMed Central

    Herrmann, Kelsey; Erokwu, Bernadette O.; Johansen, Mette L.; Basilion, James P.; Gulani, Vikas; Griswold, Mark A.; Flask, Chris A.; Brady-Kalnay, Susann M.

    2016-01-01

    Human brain tumors such as glioblastomas are typically detected using conventional, nonquantitative magnetic resonance imaging (MRI) techniques, such as T2-weighted and contrast enhanced T1-weighted MRI. In this manuscript, we tested whether dynamic quantitative T1 mapping by MRI can localize orthotopic glioma tumors in an objective manner. Quantitative T1 mapping was performed by MRI over multiple time points using the conventional contrast agent Optimark. We compared signal differences to determine the gadolinium concentration in tissues over time. The T1 parametric maps made it easy to identify the regions of contrast enhancement and thus tumor location. Doubling the typical human dose of contrast agent resulted in a clearer demarcation of these tumors. Therefore, T1 mapping of brain tumors is gadolinium dose dependent and improves detection of tumors by MRI. The use of T1 maps provides a quantitative means to evaluate tumor detection by gadolinium-based contrast agents over time. This dynamic quantitative T1 mapping technique will also enable future quantitative evaluation of various targeted MRI contrast agents. PMID:27084431

  9. SirT1 in muscle physiology and disease: lessons from mouse models

    PubMed Central

    Vinciguerra, Manlio; Fulco, Marcella; Ladurner, Andreas; Sartorelli, Vittorio; Rosenthal, Nadia

    2010-01-01

    Sirtuin 1 (SirT1) is the largest of the seven members of the sirtuin family of class III nicotinamide adenine dinucleotide (NAD+)-dependent protein deacetylases, whose activation is beneficial for metabolic, neurodegenerative, inflammatory and neoplastic diseases, and augments life span in model organisms (Finkel et al., 2009; Lavu et al., 2008). In vitro studies show that SirT1 protects genome integrity and is involved in circadian physiological rhythms (Asher et al., 2008; Nakahata et al., 2008; Oberdoerffer et al., 2008). In the last few years, a fundamental role for SirT1 in the metabolism and differentiation of skeletal muscle cells has been uncovered (Fulco et al., 2003), and the use of specific transgenic or knockout SirT1 mouse models implicates it in the protection of heart muscle from oxidative and hypertrophic stresses (Alcendor et al., 2007). In this Perspective, we review the recent exciting findings that have established a key role for the ’longevity’ protein SirT1 in skeletal and heart muscle physiology and disease. Furthermore, given the multiple biological functions of SirT1, we discuss the unique opportunities that SirT1 mouse models can offer to improve our integrated understanding of the metabolism, as well as the regeneration and aging-associated changes in the circadian function, of skeletal and heart muscle. PMID:20354108

  10. Reduced proliferative activity of primary POMGnT1-null myoblasts in vitro.

    PubMed

    Miyagoe-Suzuki, Yuko; Masubuchi, Nami; Miyamoto, Kaori; Wada, Michiko R; Yuasa, Shigeki; Saito, Fumiaki; Matsumura, Kiichiro; Kanesaki, Hironori; Kudo, Akira; Manya, Hiroshi; Endo, Tamao; Takeda, Shin'ichi

    2009-01-01

    Protein O-linked mannose beta1,2-N-acetylglucosaminyltransferase 1 (POMGnT1) is an enzyme that transfers N-acetylglucosamine to O-mannose of glycoproteins. Mutations of the POMGnT1 gene cause muscle-eye-brain (MEB) disease. To obtain a better understanding of the pathogenesis of MEB disease, we mutated the POMGnT1 gene in mice using a targeting technique. The mutant muscle showed aberrant glycosylation of alpha-DG, and alpha-DG from mutant muscle failed to bind laminin in a binding assay. POMGnT1(-/-) muscle showed minimal pathological changes with very low-serum creatine kinase levels, and had normally formed muscle basal lamina, but showed reduced muscle mass, reduced numbers of muscle fibers, and impaired muscle regeneration. Importantly, POMGnT1(-/-) satellite cells proliferated slowly, but efficiently differentiated into multinuclear myotubes in vitro. Transfer of a retrovirus vector-mediated POMGnT1 gene into POMGnT1(-/-) myoblasts completely restored the glycosylation of alpha-DG, but proliferation of the cells was not improved. Our results suggest that proper glycosylation of alpha-DG is important for maintenance of the proliferative activity of satellite cells in vivo. PMID:19114101

  11. Perturbative harmonic modulation of longitudinal electron-spin magnetization for short T1 determination

    NASA Astrophysics Data System (ADS)

    Suzuki, Takayuki

    2015-10-01

    Longitudinally detected T1 measurement scheme (LOD-T1) is studied in detail. In contrast to the original work on LOD-T1, using high power microwave pulses, this work deals with general and practically frequent cases in which perfect inversion of the electron-spin magnetization is not feasible due to the effect of relaxation during microwave pulses. Theoretical studies, numerical simulations, and experiments reveal a pair of separate contributions of the dynamics of the longitudinal magnetization to the LOD signal, namely, the periodic modulation and the relaxation contributions. The latter alone which is of interest can be extracted to give relaxation curves. In addition, it is shown that T1 information can be obtained even when the available microwave power is so low that the electron magnetization can only be perturbatively modulated, at the cost of reduced sensitivity. To overcome this, a modified pulse sequence is proposed. In this new method, the pulse excitations are repeated during half a period of the resonance of the longitudinal detection circuit. The method is called the perturbative harmonic modulation method for longitudinally detected T1 measurement (HM-LOD-T1). HM-LOD-T1 experiments are demonstrated in 2,2-diphenyl-1-picrylhydrazyl (DPPH).

  12. Acute astrocyte activation in brain detected by MRI: new insights into T(1) hypointensity.

    PubMed

    Sibson, Nicola R; Lowe, John P; Blamire, Andrew M; Martin, Matthew J; Obrenovitch, Tiho P; Anthony, Daniel C

    2008-03-01

    Increases in the T(1) of brain tissue, which give rise to dark or hypointense areas on T(1)-weighted images using magnetic resonance imaging (MRI), are common to a number of neuropathologies including multiple sclerosis (MS) and ischaemia. However, the biologic significance of T(1) increases remains unclear. Using a multiparametric MRI approach and well-defined experimental models, we have experimentally induced increases in tissue T(1) to determine the underlying cellular basis of such changes. We have shown that a rapid acute increase in T(1) relaxation in the brain occurs in experimental models of both low-flow ischaemia induced by intrastriatal injection of endothelin-1 (ET-1), and excitotoxicity induced by intrastriatal injection of N-methyl-D-aspartate (NMDA). However, there appears to be no consistent correlation between increases in T(1) relaxation and changes in other MRI parameters (apparent diffusion coefficient, T(2) relaxation, or magnetisation transfer ratio of tissue water). Immunohistochemically, one common morphologic feature shared by the ET-1 and NMDA models is acute astrocyte activation, which was detectable within 2 h of intracerebral ET-1 injection. Pretreatment with an inhibitor of astrocyte activation, arundic acid, significantly reduced the spatial extent of the T(1) signal change induced by intrastriatal ET-1 injection. These findings suggest that an increase in T(1) relaxation may identify the acute development of reactive astrocytes within a central nervous system lesion. Early changes in T(1) may, therefore, provide insight into acute and reversible injury processes in neurologic patients, such as those observed before contrast enhancement in MS. PMID:17851455

  13. Sodium and T1ρ MRI for molecular and diagnostic imaging of articular cartilage†

    PubMed Central

    Borthakur, Arijitt; Mellon, Eric; Niyogi, Sampreet; Witschey, Walter; Kneeland, J. Bruce; Reddy, Ravinder

    2010-01-01

    In this article, both sodium magnetic resonance (MR) and T1ρ relaxation mapping aimed at measuring molecular changes in cartilage for the diagnostic imaging of osteoarthritis are reviewed. First, an introduction to structure of cartilage, its degeneration in osteoarthritis (OA) and an outline of diagnostic imaging methods in quantifying molecular changes and early diagnostic aspects of cartilage degeneration are described. The sodium MRI section begins with a brief overview of the theory of sodium NMR of biological tissues and is followed by a section on multiple quantum filters that can be used to quantify both bi-exponential relaxation and residual quadrupolar interaction. Specifically, (i) the rationale behind the use of sodium MRI in quantifying proteoglycan (PG) changes, (ii) validation studies using biochemical assays, (iii) studies on human OA specimens, (iv) results on animal models and (v) clinical imaging protocols are reviewed. Results demonstrating the feasibility of quantifying PG in OA patients and comparison with that in healthy subjects are also presented. The section concludes with the discussion of advantages and potential issues with sodium MRI and the impact of new technological advancements (e.g. ultra-high field scanners and parallel imaging methods). In the theory section on T1ρ, a brief description of (i) principles of measuring T1ρ relaxation, (ii) pulse sequences for computing T1ρ relaxation maps, (iii) issues regarding radio frequency power deposition, (iv) mechanisms that contribute to T1ρ in biological tissues and (v) effects of exchange and dipolar interaction on T1ρ dispersion are discussed. Correlation of T1ρ relaxation rate with macromolecular content and biomechanical properties in cartilage specimens subjected to trypsin and cytokine-induced glycosaminoglycan depletion and validation against biochemical assay and histopathology are presented. Experimental T1ρ data from osteoarthritic specimens, animal models, healthy human

  14. Essential Parameters for Structural Analysis and Dereplication by 1H NMR Spectroscopy

    PubMed Central

    2015-01-01

    The present study demonstrates the importance of adequate precision when reporting the δ and J parameters of frequency domain 1H NMR (HNMR) data. Using a variety of structural classes (terpenoids, phenolics, alkaloids) from different taxa (plants, cyanobacteria), this study develops rationales that explain the importance of enhanced precision in NMR spectroscopic analysis and rationalizes the need for reporting Δδ and ΔJ values at the 0.1–1 ppb and 10 mHz level, respectively. Spectral simulations paired with iteration are shown to be essential tools for complete spectral interpretation, adequate precision, and unambiguous HNMR-driven dereplication and metabolomic analysis. The broader applicability of the recommendation relates to the physicochemical properties of hydrogen (1H) and its ubiquity in organic molecules, making HNMR spectra an integral component of structure elucidation and verification. Regardless of origin or molecular weight, the HNMR spectrum of a compound can be very complex and encode a wealth of structural information that is often obscured by limited spectral dispersion and the occurrence of higher order effects. This altogether limits spectral interpretation, confines decoding of the underlying spin parameters, and explains the major challenge associated with the translation of HNMR spectra into tabulated information. On the other hand, the reproducibility of the spectral data set of any (new) chemical entity is essential for its structure elucidation and subsequent dereplication. Handling and documenting HNMR data with adequate precision is critical for establishing unequivocal links between chemical structure, analytical data, metabolomes, and biological activity. Using the full potential of HNMR spectra will facilitate the general reproducibility for future studies of bioactive chemicals, especially of compounds obtained from the diversity of terrestrial and marine organisms. PMID:24895010

  15. Equilibrium 2H/ 1H fractionations in organic molecules: I. Experimental calibration of ab initio calculations

    NASA Astrophysics Data System (ADS)

    Wang, Ying; Sessions, Alex L.; Nielsen, Robert J.; Goddard, William A., III

    2009-12-01

    Carbon-bound hydrogen in sedimentary organic matter can undergo exchange over geologic timescales, altering its isotopic composition. Studies investigating the natural abundance distribution of 1H and 2H in such molecules must account for this exchange, which in turn requires quantitative knowledge regarding the endpoint of exchange, i.e., the equilibrium isotopic fractionation factor ( α eq). To date, relevant data have been lacking for molecules larger than methane. Here we describe an experimental method to measure α eq for C-bound H positions adjacent to carbonyl group (H α) in ketones. H at these positions equilibrates on a timescale of days as a result of keto-enol tautomerism, allowing equilibrium 2H/ 1H distributions to be indirectly measured. Molecular vibrations for the same ketone molecules are then computed using Density Functional Theory at the B3LYP/6-311G∗∗ level and used to calculate α eq values for H α. Comparison of experimental and computational results for six different straight and branched ketones yields a temperature-dependent linear calibration curve with slope = 1.081-0.00376 T and intercept = 8.404-0.387 T, where T is temperature in degrees Celsius. Since the dominant systematic error in the calculation (omission of anharmonicity) is of the same size for ketones and C-bound H in most other linear compounds, we propose that this calibration can be applied to analogous calculations for a wide variety of organic molecules with linear carbon skeletons for temperatures below 100 °C. In a companion paper ( Wang et al., 2009) we use this new calibration dataset to calculate the temperature-dependent equilibrium isotopic fractionation factors for a range of linear hydrocarbons, alcohols, ethers, ketones, esters and acids.

  16. Essential parameters for structural analysis and dereplication by (1)H NMR spectroscopy.

    PubMed

    Pauli, Guido F; Chen, Shao-Nong; Lankin, David C; Bisson, Jonathan; Case, Ryan J; Chadwick, Lucas R; Gödecke, Tanja; Inui, Taichi; Krunic, Aleksej; Jaki, Birgit U; McAlpine, James B; Mo, Shunyan; Napolitano, José G; Orjala, Jimmy; Lehtivarjo, Juuso; Korhonen, Samuli-Petrus; Niemitz, Matthias

    2014-06-27

    The present study demonstrates the importance of adequate precision when reporting the δ and J parameters of frequency domain (1)H NMR (HNMR) data. Using a variety of structural classes (terpenoids, phenolics, alkaloids) from different taxa (plants, cyanobacteria), this study develops rationales that explain the importance of enhanced precision in NMR spectroscopic analysis and rationalizes the need for reporting Δδ and ΔJ values at the 0.1-1 ppb and 10 mHz level, respectively. Spectral simulations paired with iteration are shown to be essential tools for complete spectral interpretation, adequate precision, and unambiguous HNMR-driven dereplication and metabolomic analysis. The broader applicability of the recommendation relates to the physicochemical properties of hydrogen ((1)H) and its ubiquity in organic molecules, making HNMR spectra an integral component of structure elucidation and verification. Regardless of origin or molecular weight, the HNMR spectrum of a compound can be very complex and encode a wealth of structural information that is often obscured by limited spectral dispersion and the occurrence of higher order effects. This altogether limits spectral interpretation, confines decoding of the underlying spin parameters, and explains the major challenge associated with the translation of HNMR spectra into tabulated information. On the other hand, the reproducibility of the spectral data set of any (new) chemical entity is essential for its structure elucidation and subsequent dereplication. Handling and documenting HNMR data with adequate precision is critical for establishing unequivocal links between chemical structure, analytical data, metabolomes, and biological activity. Using the full potential of HNMR spectra will facilitate the general reproducibility for future studies of bioactive chemicals, especially of compounds obtained from the diversity of terrestrial and marine organisms. PMID:24895010

  17. Age-Related 1H NMR Characterization of Cerebrospinal Fluid in Newborn and Young Healthy Piglets

    PubMed Central

    Barone, Francesca; Elmi, Alberto; Romagnoli, Noemi; Bacci, Maria Laura

    2016-01-01

    When it comes to neuroscience, pigs represent an important animal model due to their resemblance with humans’ brains for several patterns including anatomy and developmental stages. Cerebrospinal fluid (CSF) is a relatively easy-to-collect specimen that can provide important information about neurological health and function, proving its importance as both a diagnostic and biomedical monitoring tool. Consequently, it would be of high scientific interest and value to obtain more standard physiological information regarding its composition and dynamics for both swine pathology and the refinement of experimental protocols. Recently, proton nuclear magnetic resonance (1H NMR) spectroscopy has been applied in order to analyze the metabolomic profile of this biological fluid, and results showed the technique to be highly reproducible and reliable. The aim of the present study was to investigate in both qualitative and quantitative manner the composition of Cerebrospinal Fluid harvested form healthy newborn (5 days old-P5) and young (30-P30 and 50-P50 days old) piglets using 1H NMR Spectroscopy, and to analyze any possible difference in metabolites concentration between age groups, related to age and Blood-Brain-Barrier maturation. On each of the analyzed samples, 30 molecules could be observed above their limit of quantification, accounting for 95–98% of the total area of the spectra. The concentrations of adenine, tyrosine, leucine, valine, 3-hydroxyvalerate, 3-methyl-2-oxovalerate were found to decrease between P05 and P50, while the concentrations of glutamine, creatinine, methanol, trimethylamine and myo-inositol were found to increase. The P05-P30 comparison was also significant for glutamine, creatinine, adenine, tyrosine, leucine, valine, 3-hydroxyisovalerate, 3-methyl-2-oxovalerate, while for the P30-P50 comparison we found significant differences for glutamine, myo-inositol, leucine and trimethylamine. None of these molecules showed at P30 concentrations

  18. The Peculiar Radio-loud Narrow Line Seyfert 1 Galaxy 1H 0323+342

    NASA Astrophysics Data System (ADS)

    Paliya, Vaidehi S.; Sahayanathan, S.; Parker, M. L.; Fabian, A. C.; Stalin, C. S.; Anjum, Ayesha; Pandey, S. B.

    2014-07-01

    We present a multiwavelength study of the radio-loud narrow-line Seyfert 1 galaxy (NLSy1) 1H 0323+342, detected by the Fermi Gamma-Ray Space Telescope. Multiband light curves show many orphan X-ray and optical flares having no corresponding γ-ray counterparts. Such anomalous variability behavior can be due to different locations of the emission region from the central source. During a large flare, a γ-ray flux doubling timescale as small as ~3 hr is noticed. We built spectral energy distributions (SEDs) during different activity states and modeled them using a one-zone leptonic model. The shape of the optical/UV component of the SEDs is dominated by accretion disk emission in all the activity states. In the X-ray band, significant thermal emission from the hot corona is inferred during quiescent and first flaring states; however, during subsequent flares, the nonthermal jet component dominates. The γ-ray emission in all the states can be well explained by inverse-Compton scattering of accretion disk photons reprocessed by the broad-line region. The source showed violent intra-night optical variability, coinciding with one of the high γ-ray activity states. An analysis of the overall X-ray spectrum fitted with an absorbed power-law plus relativistic reflection component hints at the presence of an Fe Kα line and returns a high black hole spin value of a = 0.96 ± 0.14. We argue that 1H 0323+342 possesses dual characteristics, akin to both flat-spectrum radio quasars (FSRQs) and radio-quiet NLSy1 galaxies, though at a low jet power regime compared to powerful FSRQs.

  19. The peculiar radio-loud narrow line Seyfert 1 galaxy 1H 0323+342

    SciTech Connect

    Paliya, Vaidehi S.; Stalin, C. S.; Sahayanathan, S.; Parker, M. L.; Fabian, A. C.; Anjum, Ayesha; Pandey, S. B.

    2014-07-10

    We present a multiwavelength study of the radio-loud narrow-line Seyfert 1 galaxy (NLSy1) 1H 0323+342, detected by the Fermi Gamma-Ray Space Telescope. Multiband light curves show many orphan X-ray and optical flares having no corresponding γ-ray counterparts. Such anomalous variability behavior can be due to different locations of the emission region from the central source. During a large flare, a γ-ray flux doubling timescale as small as ∼3 hr is noticed. We built spectral energy distributions (SEDs) during different activity states and modeled them using a one-zone leptonic model. The shape of the optical/UV component of the SEDs is dominated by accretion disk emission in all the activity states. In the X-ray band, significant thermal emission from the hot corona is inferred during quiescent and first flaring states; however, during subsequent flares, the nonthermal jet component dominates. The γ-ray emission in all the states can be well explained by inverse-Compton scattering of accretion disk photons reprocessed by the broad-line region. The source showed violent intra-night optical variability, coinciding with one of the high γ-ray activity states. An analysis of the overall X-ray spectrum fitted with an absorbed power-law plus relativistic reflection component hints at the presence of an Fe Kα line and returns a high black hole spin value of a = 0.96 ± 0.14. We argue that 1H 0323+342 possesses dual characteristics, akin to both flat-spectrum radio quasars (FSRQs) and radio-quiet NLSy1 galaxies, though at a low jet power regime compared to powerful FSRQs.

  20. Acute Megakaryoblastic Leukemia with t(1;22) Mimicking Neuroblastoma in an Infant

    PubMed Central

    Gökçe, Müge; Aytaç, Selin; Ünal, Şule; Altan, İlhan; Gümrük, Fatma; Çetin, Mualla

    2015-01-01

    Acute megakaryoblastic leukemia (AMKL) with t(1;22) (p13;q13) is an extremely rare subtype of acute myeloid leukemia that is almost always described in infants. t(1;22) (p13;q13)-positive AMKL with extramedullary infiltration has been previously reported only once in the literature. Herein, we report a 3-month-old infant presenting with a pelvic mass and pancytopenia suggesting neuroblastoma. Bone marrow evaluation revealed t(1;22)-positive AMKL that responded well to a regimen containing high-dose cytarabine. PMID:25805677

  1. Thin film NMR T1 measurement by MRFM using cyclic adiabatic inversion

    NASA Astrophysics Data System (ADS)

    Kwon, Sungmin; Saun, Seung-Bo; Lee, Soonchil; Won, Soonho

    2014-03-01

    We obtained the NMR spectrum and the spin lattice relaxation time (T1) for thin film samples using Magnetic Resonance Force Microscopy (MRFM). The samples were Alq3, which is widely used as an organic light emitting diode (OLED), thin films of 150 nm thick and a bulk crystal. T1 was measured by using the cyclic adiabatic inversion method at a fixed frequency of 297 MHz and at 12 K. To confirm the reliability of our measurement technique we compared the result with that obtained by conventional NMR method. T1 of thin film samples was measured and compared with that of the bulk sample. thin film, MRFM.

  2. T1-201 per rectum: A noninvasive method for evaluating portosystemic shunt

    SciTech Connect

    Verdickt, X.; Reding, P.; Tshiamala, P.; Ham, H.R.

    1984-01-01

    Portosystemic shunt is one of the most important complications of liver cirrhosis. Unfortunately, current methods for detecting and quantifying this shunt are either non-specific or associated with significant morbidity. The aim of this work was to evaluate the clinical value of a new non-traumatic method which consisted of administrating T1-201 per rectum and monitoring the absorbed activity using a camera and a computer system. The method assumes that in the absence of portosystemic shunt, most of the absorbed activity will be fixed in the liver while in the presence of this shunt, some of the activity will be fixed in the myocardium. The ratio of heart to liver activity can therefore be used to evaluate the importance of the portosystemic shunt. 34 subjects have been studied. The ratio of heart to liver activity at the 25th minute after the tracer administration is higher in patients with liver cirrhosis (n=22, m=.9, s.d.=.37) than in patients with steatosis (n=10, m=.28, s.d.=.03). In two healthy subjects investigated the H/L ratio was .27 and .30. The reproducibility of the test was evaluated in 8 subjects and showed a good reproducibility (mean of difference =.03, range=.01 to .07). Patients with esophageal varices had always a high H/L ratio while some patients with liver cirrhosis without esophageal varices had also high H/L ratio, probably due to the presence of intrahepatic shunt. The authors' results showed the value of this new non-traumatic test for detecting and quantifying extra- as well as intrahepatic portosystematic shunt.

  3. Discrimination of Basal Cell Carcinoma from Normal Skin Tissue Using High-Resolution Magic Angle Spinning 1H NMR Spectroscopy

    PubMed Central

    Mun, Je-Ho; Lee, Heonho; Yoon, Dahye; Kim, Byung-Soo; Kim, Moon-Bum; Kim, Shukmann

    2016-01-01

    High-resolution magic angle spinning nuclear magnetic resonance (HR-MAS NMR) spectroscopy is a useful tool for investigating the metabolism of various cancers. Basal cell carcinoma (BCC) is the most common skin cancer. However, to our knowledge, data on metabolic profiling of BCC have not been reported in the literature. The objective of the present study was to investigate the metabolic profiling of cutaneous BCC using HR-MAS 1H NMR spectroscopy. HR-MAS 1H NMR spectroscopy was used to analyze the metabolite profile and metabolite intensity of histopathologically confirmed BCC tissues and normal skin tissue (NST) samples. The metabolic intensity normalized to the total spectral intensities in BCC and NST was compared, and multivariate analysis was performed with orthogonal partial least-squares discriminant analysis (OPLS-DA). P values < 0.05 were considered statistically significant. Univariate analysis revealed 9 metabolites that showed statistically significant difference between BCC and NST. In multivariate analysis, the OPLS-DA models built with the HR-MAS NMR metabolic profiles revealed a clear separation of BCC from NST. The receiver operating characteristic curve generated from the results revealed an excellent discrimination of BCC from NST with an area under the curve (AUC) value of 0.961. The present study demonstrated that the metabolite profile and metabolite intensity differ between BCC and NST, and that HR-MAS 1H NMR spectroscopy can be a valuable tool in the diagnosis of BCC. PMID:26934749

  4. 1H NMR study of proton dynamics in the inorganic solid acid Rb3 H( SO4 )2

    NASA Astrophysics Data System (ADS)

    Suzuki, Koh-Ichi; Hayashi, Shigenobu

    2006-01-01

    Proton dynamics in Rb3H(SO4)2 has been studied by means of H1 NMR. The H1 magic-angle-spinning (MAS) NMR spectra were traced at room temperature (RT) at Larmor frequency of 400.13MHz . H1 static NMR spectra were measured at frequencies of 200.13MHz and 400.13MHz in the ranges of 165-513 and 300-513K , respectively. H1 spin-lattice relaxation times, T1 , were measured at 200.13 and 19.65MHz in the ranges of 260-513 and 260-470K , respectively. The H1 MAS NMR spectrum at 294K has an isotropic chemical shift of 16.3ppm from tetramethylsilane, demonstrating very strong hydrogen bonds. In RT phase, a wobbling motion of the O-H axis in one direction at the fast motional limit takes place above 400K , being supported by the H1 static NMR spectral line shapes and by the H1 T1 values. In the high temperature (HT) phase, the sharp H1 static NMR spectra indicate translational proton diffusion. From the analysis of H1 T1 , protons diffuse with the inverse of the frequency factor (τ0) of 9.5×10-13s and the activation energy (Ea) of 25kJmol-1 . These parameters can well explain the macroscopic electric conductivity in HT phase.

  5. The role of glutathione S-transferase M1 and T1 gene polymorphisms and fruit and vegetable consumption in antioxidant parameters in healthy subjects.

    PubMed

    Yuan, Lin-Hong; Meng, Li-Ping; Ma, Wei-Wei; Li, Sheng; Feng, Jin-Fang; Yu, Huan-Ling; Xiao, Rong

    2012-03-01

    The correlation of glutathione S-transferase (GST) M1/T1 genetic polymorphisms with oxidative stress-related chronic diseases was proved recently. The aim of the present study was to investigate the association of GSTM1/T1 genetic polymorphisms with antioxidant biomarkers and consumption of fruits and vegetables (F&V) in healthy subjects. In this study, for conducting a 3 d dietary survey, 190 healthy adults were recruited. After DNA extraction, a multiple PCR method was used for GSTM1/T1 genotyping. A spectrophotometer method was applied for the determination of plasma total antioxidant capacity (T-AOC), vitamin C level and erythrocyte GST enzyme activity. A general linear model was used to compare the mean values of antioxidant parameters for different GSTM1/T1 genotypes and consumption of F&V. Polymorphisms of GSTM1/T1 had no effects on plasma T-AOC and vitamin C levels. Deletion of the GSTM1 gene decreased the erythrocyte GST activity. There was correlation between plasma T-AOC and consumption of F&V in the GSTM1⁻ or GSTT1⁺ subjects. A similar pattern was evident for erythrocyte GST activity in the GSTM1⁻ subjects. No association was found among consumption of F&V and GSTM1/T1 genotypes and plasma vitamin C level. Different consumption of F&V had no impact on plasma T-AOC and vitamin C levels in the GSTM1⁻/GSTT1⁺ or GSTM1⁻/GSTT1⁻ subjects. The erythrocyte GST activity was more sensitive to consumption of F&V in the individuals with the GSTM1⁻/GSTT1⁺ genotype. Association was found among GSTM1/T1 genotypes, antioxidant parameters and consumption of F&V. Large-scale and multiple ethnic studies are needed to further evaluate the relationship. PMID:21896242

  6. Intrauterine fetal brain NMR spectroscopy: 1H and 31P studies in rats

    SciTech Connect

    Nakada, T.; Kwee, I.L.; Suzuki, N.; Houkin, K. )

    1989-11-01

    Fetal brain metabolism was investigated in utero noninvasively using multinuclear nuclear magnetic resonance spectroscopy in rats at two representative prenatal stages: early (17-18 days) and late (20-21 days) stages. Phosphorus-31 (31P) spectroscopy revealed that phosphocreatine is significantly lower in the early stage and increases to the level of early neonates by the late prenatal stage. Intracellular pH at the early stage was found to be strikingly high (7.52 +/- 0.21) and decreased to a level similar to that of neonates by the late stage (7.29 +/- 0.07). Phosphomonoester levels at both stages were similar to the values reported for early neonates. Water-suppressed proton (1H) spectroscopy demonstrated a distinctive in vivo fetal brain spectral pattern characterized by low levels of N-acetyl aspartate and high levels of taurine. High-resolution proton spectroscopy and homonuclear chemical-shift correlate spectroscopy of brain perchloric acid extracts confirmed these in vivo findings. In vitro 31P spectroscopy of acidified chloroform methanol extracts showed the characteristic membrane phospholipid profiles of fetal brain. The phosphatidylethanolamine (PE)-to-phosphatidylcholine (PC) ratio (PE/PC) did not show significant changes between the two stages at 0.40 +/- 0.11, a value similar to that of early neonates.

  7. /sup 1/H and /sup 13/C spin-lattice relaxation in gaseous benzene

    SciTech Connect

    Folkendt, M.M.; Weiss-Lopez, B.E.; True, N.S.

    1988-08-25

    The nuclear spin-lattice relaxation time, T/sub 1/, measured for benzene protons at densities between 0.81 and 54.4 mol/m/sup 3/ (15 and 980 Torr) at 381 K exhibits a characteristic nonlinear density dependence. Analysis of the density-dependent T/sub 1/ data yields a spin-rotation coupling constant, C/sub eff/, of /vert bar/182.6 (0.4)/vert bar/ Hz and an angular momentum reorientation cross section, sigma, of 131 (1) /Angstrom//sup 2/. The /sup 13/C spin-lattice relaxation time of singly labeled /sup 13/C benzene is a linear function of density over the density range 1.07-75.12 mol/m/sup 3/ (20-1330 Torr). /sup 13/C T/sub 1/ values are shorter than /sup 1/H T/sub 1/ values by a factor of ca. 100 at comparable densities. The nuclear Overhauser enhancement factor, /eta/, is 0.0 /plus minus/ 0.02 at densities between 11 and 85.3 mol/m/sup 3/ (200 and 1500 Torr), demonstrating that dipole-dipole relaxation is relatively inefficient in this region. The spin-rotation coupling constant, C/sub eff/, for /sup 13/C nuclei in benzene is estimated to be /vert bar/1602 (68)/vert bar/ Hz.

  8. Use of Voigt lineshape for quantification of in vivo 1H spectra.

    PubMed

    Marshall, I; Higinbotham, J; Bruce, S; Freise, A

    1997-05-01

    Quantification of NMR visible metabolites by spectral modeling usually assumes a Lorentzian or Gaussian lineshape, despite the fact that experimental lineshapes are neither. To minimize systematic fitting errors, a mixed Lorentzian-Gaussian (Voigt) lineshape model was developed. When tested with synthetic FIDs, the Voigt lineshape model gave more accurate results (maximum error 2%) than either Lorentzian (maximum error 20%) or Gaussian models (maximum error 12%). The three lineshape models gave substantially different peak areas in an in vitro experiment, with the Voigt model having a much lower chi2 (2.1 compared with 5.2 for the Lorentzian model and 6.2 for the Gaussian model). In a group of 10 healthy volunteers, fitting of 1H spectra from cerebral white matter gave significantly different peak areas between the methods. Even when area ratios were taken, the Lorentzian model gave higher values (+5% for NAA/choline and +2% for NAA/creatine) than the Voigt lineshape model, whereas the Gaussian model gave lower values (-2% and -1%, respectively). PMID:9126938

  9. The origin of molecular mobility during biomass pyrolysis as revealed by in situ (1)H NMR spectroscopy.

    PubMed

    Dufour, Anthony; Castro-Diaz, Miguel; Brosse, Nicolas; Bouroukba, Mohamed; Snape, Colin

    2012-07-01

    The thermochemical conversion of lignocellulosic biomass feedstocks offers an important potential route for the production of biofuels and value-added green chemicals. Pyrolysis is the first phenomenon involved in all biomass thermochemical processes and it controls to a major extent the product composition. The composition of pyrolysis products can be affected markedly by the extent of softening that occurs. In spite of extensive work on biomass pyrolysis, the development of fluidity during the pyrolysis of biomass has not been quantified. This paper provides the first experimental investigation of proton mobility during biomass pyrolysis by in situ (1)H NMR spectroscopy. The origin of mobility is discussed for cellulose, lignin and xylan. The effect of minerals on cellulose mobility is also investigated. Interactions between polymers in the native biomass network are revealed by in situ (1)H NMR analysis. PMID:22573541

  10. Energetic derivatives of 5-(5-amino-2H-1,2,3-triazol-4-yl)-1H-tetrazole.

    PubMed

    Izsák, Dániel; Klapötke, Thomas M; Pflüger, Carolin

    2015-10-21

    This study presents the preparation of the novel nitrogen-rich compound 5-(5-amino-2H-1,2,3-triazol-4-yl)-1H-tetrazole (5) from commercially available chemicals in a five step synthesis. The more energetic derivatives with azido (6) and nitro (7) groups, as well as a diazene bridge (8) were also successfully prepared. The energetic compounds were comprehensively characterized by various means, including vibrational (IR, Raman) and multinuclear ((1)H, (13)C, (14)N, (15)N) NMR spectroscopy, mass spectrometry and differential thermal analysis. The sensitivities towards important outer stimuli (impact, friction, electrostatic discharge) were determined according to BAM standards. The enthalpies of formation were calculated on the CBS-4M level of theory, revealing highly endothermic values, and were utilized to calculate the detonation parameters using EPXLO5 (6.02). PMID:26361356

  11. Quantification of white matter and gray matter volumes from T1 parametric images using fuzzy classifiers.

    PubMed

    Herndon, R C; Lancaster, J L; Toga, A W; Fox, P T

    1996-01-01

    White matter (WM) and gray matter (GM) were accurately measured using a technique based on a single standardized fuzzy classifier (FC) for each tissue. Fuzzy classifier development was based on experts' visual assessments of WM and GM boundaries from a set of T1 parametric MR images. The fuzzy classifier method's accuracy was validated and optimized by a set of T1 phantom images that were based on hand-detailed human brain cryosection images. Nine sets of axial T1 images of varying thickness equally distributed throughout the brain were simulated. All T1 data sets were mapped to the standardized FCs and rapidly segmented into WM and GM voxel fraction images. Resulting volumes revealed that, in most cases, the difference between measured and actual volumes was less than 5%. This was consistent throughout most of the brain, and as expected, the accuracy improved to generally less than 2% for the 1-mm simulated brain slices. PMID:8724407

  12. A synergistically enhanced T(1) -T(2) dual-modal contrast agent.

    PubMed

    Zhou, Zijian; Huang, Dengtong; Bao, Jianfeng; Chen, Qiaoli; Liu, Gang; Chen, Zhong; Chen, Xiaoyuan; Gao, Jinhao

    2012-12-01

    Monodisperse Gd(2) O(3) -embedded iron oxide (GdIO) nanoparticles can simultaneously enhance the local magnetic field intensities of each other under an external magnetic field and result in synergistic enhancement of T(1) and T(2) effects. GdIO nanoparticles have the unique property to be both T(1) and T(2) contrast agents and can potentially lead to higher accuracy in cancer diagnosis, particularly liver tumors. PMID:22972529

  13. Errors in quantitative T1rho imaging and the correction methods.

    PubMed

    Chen, Weitian

    2015-08-01

    The spin-lattice relaxation time constant in rotating frame (T1rho) is useful for assessment of the properties of macromolecular environment inside tissue. Quantification of T1rho is found promising in various clinical applications. However, T1rho imaging is prone to image artifacts and quantification errors, which remains one of the greatest challenges to adopt this technique in routine clinical practice. The conventional continuous wave spin-lock is susceptible to B1 radiofrequency (RF) and B0 field inhomogeneity, which appears as banding artifacts in acquired images. A number of methods have been reported to modify T1rho prep RF pulse cluster to mitigate this effect. Adiabatic RF pulse can also be used for spin-lock with insensitivity to both B1 RF and B0 field inhomogeneity. Another source of quantification error in T1rho imaging is signal evolution during imaging data acquisition. Care is needed to affirm such error does not take place when specific pulse sequence is used for imaging data acquisition. Another source of T1rho quantification error is insufficient signal-to-noise ratio (SNR), which is common among various quantitative imaging approaches. Measurement of T1rho within an ROI can mitigate this issue, but at the cost of reduced resolution. Noise-corrected methods are reported to address this issue in pixel-wise quantification. For certain tissue type, T1rho quantification can be confounded by magic angle effect and the presence of multiple tissue components. Review of these confounding factors from inherent tissue properties is not included in this article. PMID:26435922

  14. Complete Genome Sequences of T1-Like Phages JMPW1 and JMPW2

    PubMed Central

    Shen, Mengyu; Zhu, Hongbin; Le, Shuai; Li, Gang; Tan, Yinling; Zhao, Xia; Shen, Wei

    2016-01-01

    We report the complete genome sequences of phages JMPW1 (49,840 bp) and JMPW2 (50,298 bp), two T1-like Escherichia coli phages isolated from contaminated experiment samples. Although the genomes of JMPW1 and JMPW2 share high identity with T1, they show some differences, which are mainly located in several genes with unknown functions and genes encoding tail fiber proteins and endonucleases. PMID:27340070

  15. Native Myocardial T1 as a Biomarker of Cardiac Structure in Non-Ischemic Cardiomyopathy.

    PubMed

    Shah, Ravi V; Kato, Shingo; Roujol, Sebastien; Murthy, Venkatesh; Bellm, Steven; Kashem, Abyaad; Basha, Tamer; Jang, Jihye; Eisman, Aaron S; Manning, Warren J; Nezafat, Reza

    2016-01-15

    Diffuse myocardial fibrosis is involved in the pathology of nonischemic cardiomyopathy (NIC). Recently, the application of native (noncontrast) myocardial T1 measurement has been proposed as a method for characterizing diffuse interstitial fibrosis. To determine the association of native T1 with myocardial structure and function, we prospectively studied 39 patients with NIC (defined as left ventricular ejection fraction (LVEF) ≤ 50% without cardiac magnetic resonance (CMR) evidence of previous infarction) and 27 subjects with normal LVEF without known overt cardiovascular disease. T1, T2, and extracellular volume fraction (ECV) were determined over 16 segments across the base, mid, and apical left ventricular (LV). NIC participants (57 ± 15 years) were predominantly men (74%), with a mean LVEF 34 ± 10%. Subjects with NIC had a greater native T1 (1,131 ± 51 vs 1,069 ± 29 ms; p <0.0001), a greater ECV (0.28 ± 0.04 vs 0.25 ± 0.02, p = 0.002), and a longer myocardial T2 (52 ± 8 vs 47 ± 5 ms; p = 0.02). After multivariate adjustment, a lower global native T1 time in NIC was associated with a greater LVEF (β = -0.59, p = 0.0003), greater right ventricular ejection fraction (β = -0.47, p = 0.006), and smaller left atrial volume index (β = 0.51, p = 0.001). The regional distribution of native myocardial T1 was similar in patients with and without NIC. In NIC, native myocardial T1 is elevated in all myocardial segments, suggesting a global (not regional) abnormality of myocardial tissue composition. In conclusion, native T1 may represent a rapid, noncontrast alternative to ECV for delineating myocardial tissue remodeling in NIC. PMID:26684511

  16. Errors in quantitative T1rho imaging and the correction methods

    PubMed Central

    2015-01-01

    The spin-lattice relaxation time constant in rotating frame (T1rho) is useful for assessment of the properties of macromolecular environment inside tissue. Quantification of T1rho is found promising in various clinical applications. However, T1rho imaging is prone to image artifacts and quantification errors, which remains one of the greatest challenges to adopt this technique in routine clinical practice. The conventional continuous wave spin-lock is susceptible to B1 radiofrequency (RF) and B0 field inhomogeneity, which appears as banding artifacts in acquired images. A number of methods have been reported to modify T1rho prep RF pulse cluster to mitigate this effect. Adiabatic RF pulse can also be used for spin-lock with insensitivity to both B1 RF and B0 field inhomogeneity. Another source of quantification error in T1rho imaging is signal evolution during imaging data acquisition. Care is needed to affirm such error does not take place when specific pulse sequence is used for imaging data acquisition. Another source of T1rho quantification error is insufficient signal-to-noise ratio (SNR), which is common among various quantitative imaging approaches. Measurement of T1rho within an ROI can mitigate this issue, but at the cost of reduced resolution. Noise-corrected methods are reported to address this issue in pixel-wise quantification. For certain tissue type, T1rho quantification can be confounded by magic angle effect and the presence of multiple tissue components. Review of these confounding factors from inherent tissue properties is not included in this article. PMID:26435922

  17. Experimental investigation of T =1 analog states of 26Al and 26Mg

    NASA Astrophysics Data System (ADS)

    Srivastava, Vishal; Bhattacharya, C.; Rana, T. K.; Manna, S.; Kundu, S.; Bhattacharya, S.; Banerjee, K.; Roy, P.; Pandey, R.; Mukherjee, G.; Ghosh, T. K.; Meena, J. K.; Roy, T.; Chaudhuri, A.; Sinha, M.; Saha, A. K.; Asgar, Md. A.; Dey, A.; Roy, Subinit; Shaikh, Md. M.

    2016-04-01

    The even-even nucleus 26Mg has been studied through the reaction 27Al(d ,3He) at 25 MeV beam energy. The spectroscopic factors of the lowest (T =1 ) states of 26Mg have been extracted using the zero-range distorted wave Born approximation. These spectroscopic factors are compared with those of T =1 analog states in 26Al and found to be in good agreement.

  18. Horner's syndrome secondary to intervertebral disc herniation at the level of T1–2

    PubMed Central

    Spacey, Kate; Dannawi, Zaher; Khazim, R; Dannawi, Z

    2014-01-01

    A 54-year-old Caucasian woman presented with a 6 week history of periscapular pain and a T1 radiculopathy associated with Horner's syndrome. MRI of her cervicothoracic spine revealed an intervertebral disc herniation at the level of T1–2. During investigation she experienced some improvement in her symptoms and a conservative approach was pursued. At 6 months her pain and radiculopathy had resolved, and there was mild residual ptosis. PMID:24903729

  19. Using nitroxide spin labels. How to obtain T1e from continuous wave electron paramagnetic resonance spectra at all rotational rates.

    PubMed Central

    Haas, D A; Mailer, C; Robinson, B H

    1993-01-01

    Historically, the continuous wave electron paramagnetic resonance (CW-EPR) progressive saturation method has been used to obtain information on the spin-lattice relaxation time (T1e) and those processes, such as motion and spin exchange, that occur on a competitive timescale. For example, qualitative information on local dynamics and solvent accessibility of proteins and nucleic acids has been obtained by this method. However, making quantitative estimates of T1e from CW-EPR spectra have been frustrated by a lack of understanding of the role of T1e (and T2e) in the slow-motion regime. Theoretical simulation of the CW-EPR lineshapes in the slow-motion region under increasing power levels has been used in this work to test whether the saturation technique can produce quantitative estimates of the spin-lattice relaxation rates. A method is presented by which the correct T1e may be extracted from an analysis of the power-saturation rollover curve, regardless of the amount of inhomogeneous broadening or the rates of molecular reorientation. The range of motional correlation times from 10 to 200 ns should be optimal for extracting quantitative estimates of T1e values in spin-labeled biomolecules. The progressive-saturation rollover curve method should find wide application in those areas of biophysics where information on molecular interactions and solvent exposure as well as molecular reorientation rates are desired. PMID:8386009

  20. New approach for characterization of gelatin biopolymer films using proton behavior determined by low field 1H NMR spectrometry.

    PubMed

    Kim, Young-Teck; Hong, Young-Shick; Kimmel, Robert M; Rho, Jeong-Hae; Lee, Cherl-Ho

    2007-12-26

    The behavior of protons in biopolymer films (BFs) formed with gelatin, water, and glycerol was investigated at various relative humidities (RHs) and concentrations of glycerol using a low field 1H NMR spectrometer. At a RH of approximately 0%, the distributed spin-spin relaxation times (T2) of protons in BFs showed two components: a rapidly relaxing proton with the shortest T2 derived from protons in the rigid backbone of the gelatin polymer such as CH1-, CH2-, and CH3-, and a slowly relaxing component with longer T2 from protons of the functional groups in amino acid residues in gelatin such as -OH, -COOH, and -NH3. These two components are referred to as nonexchangeable (T2N) and exchangeable protons (T2E), respectively, indicating the different mobility of the protons. The T2E increased as RH increased indicating the increase in relative mobility of protons due to the larger free volume in the BF matrix. Above a RH of 33%, the slowest relaxing component was found in all BFs and referred to as hydration-water protons (T2W) with the highest relative mobility of all protons in the films. It suggests that the free volume in BFs can be formed above a RH of 33% in the absence of glycerol. The behaviors of T2N, T2E, and T2W reveal the formation of free volume in the BF matrix associated with the presence of plasticizers (water and glycerol). The T2 behavior in BFs is consistent with the behavior of spin-lattice relaxation (T1). Our result is the first attempt to characterize using low field 1H NMR technology how all protons in a film matrix behave and to develop correlations between proton mobility and free volume in protein-based BFs plasticized with water and glycerol. PMID:18052122

  1. Effects of pulmonary inhalation on hyperpolarized krypton-83 magnetic resonance T1 relaxation

    NASA Astrophysics Data System (ADS)

    Stupic, K. F.; Elkins, N. D.; Pavlovskaya, G. E.; Repine, J. E.; Meersmann, T.

    2011-07-01

    The 83Kr magnetic resonance (MR) relaxation time T1 of krypton gas in contact with model surfaces was previously found to be highly sensitive to surface composition, surface-to-volume ratio, and surface temperature. The work presented here explored aspects of pulmonary 83Kr T1 relaxation measurements in excised lungs from healthy rats using hyperpolarized (hp) 83Kr with approximately 4.4% spin polarization. MR spectroscopy without spatial resolution was applied to the ex vivo lungs that actively inhale hp 83Kr through a custom designed ventilation system. Various inhalation schemes were devised to study the influence of anatomical dead space upon the measured 83Kr T1 relaxation times. The longitudinal 83Kr relaxation times in the distal airways and the respiratory zones were independent of the lung inhalation volume, with T1 = 1.3 s and T1 = 1.0 s, depending only on the applied inhalation scheme. The obtained data were highly reproducible between different specimens. Further, the 83Kr T1 relaxation times in excised lungs were unaffected by the presence of up to 40% oxygen in the hp gas mixture. The results support the possible importance of 83Kr as a biomarker for evaluating lung function.

  2. Effects of Pulmonary Inhalation on Hyperpolarized Krypton-83 Magnetic Resonance T1 Relaxation

    PubMed Central

    Stupic, K.F.; Elkins, N.D.; Pavlovskaya, G.E.; Repine, J.E.; Meersmann, T.

    2011-01-01

    The 83Kr magnetic resonance (MR) relaxation time T1 of krypton gas in contact with model surfaces was previously found to be highly sensitive to surface composition, surface to volume ratio, and surface temperature. The current work explored aspects of pulmonary 83Kr T1 relaxation measurements in excised lungs from healthy rats using hyperpolarized (hp) 83Kr with approximately 4.4 % spin polarization. MR spectroscopy without spatial resolution was applied to the ex vivo lungs that actively inhale hp 83Kr through a custom designed ventilation system. Various inhalation schemes were devised to explore the influence of anatomical dead space upon the measured 83Kr T1 relaxation times. The longitudinal 83Kr relaxation times in the distal airways and the respiratory zones were independent of the lung inhalation volume, with T1 = 1.3 s and T1 = 1.0 s, depending only on the applied inhalation scheme. The obtained data was highly reproducible between different specimens. Further, the 83Kr T1 relaxation times in excised lungs were unaffected by the presence of up to 40% oxygen in the hp gas mixture. The results support the possible importance of 83Kr as a biomarker for evaluating lung function. PMID:21628780

  3. How do we manage high-grade T1 bladder cancer? Conservative or aggressive therapy?

    PubMed Central

    Kim, Seon-Kyu; Kim, Wun-Jae

    2016-01-01

    High-grade T1 bladder cancer has a poor prognosis due to a higher incidence of recurrence and progression than other nonmuscle invasive bladder cancer; thus patients with high-grade T1 have to be carefully monitored and managed. If patients are diagnosed with high-grade T1 at initial transurethral resection (TUR), a second TUR is strongly recommended regardless of whether muscle layer is present in the specimen because of the possibility of understating due to incomplete resection. Since high-grade T1 disease shows diverse clinical courses, individual approaches are recommended for treatment. In cases with low risk of progression, cystectomy could represent overtreatment and deteriorate quality of life irreversibly, while, in those with high risk, bacillus Calmette-Guérin (BCG) therapy may worsen survival by delaying definitive therapy. Therefore, a strategy for predicting prognosis based on the risk of progression is needed for managing high-grade T1 disease. Molecular risk classifiers predicting the risk of progression and response to BCG may help identify the optimal management of high-grade T1 disease for each individual. PMID:27326407

  4. T1rho and T2rho MRI in the evaluation of Parkinson's disease.

    PubMed

    Nestrasil, I; Michaeli, S; Liimatainen, T; Rydeen, C E; Kotz, C M; Nixon, J P; Hanson, T; Tuite, Paul J

    2010-06-01

    Prior work has shown that adiabatic T(1rho) and T(2rho) relaxation time constants may have sensitivity to cellular changes and the presence of iron, respectively, in Parkinson's disease (PD). Further understanding of these magnetic resonance imaging (MRI) methods and how they relate to measures of disease severity and progression in PD is needed. Using T(1rho) and T(2rho) on a 4T MRI scanner, we assessed the substantia nigra (SN) of nine non-demented moderately affected PD and ten gender- and age-matched control participants. When compared to controls, the SN of PD subjects had increased T(1rho) and reduced T(2rho). We also found a significant correlation between asymmetric motor features and asymmetry based on T(1rho). This study provides additional validation of T(1rho) and T(2rho) as a means to separate PD from control subjects, and T(1rho) may be a useful marker of asymmetry in PD. PMID:20058018

  5. T1ρ and T2ρ MRI in the evaluation of Parkinson’s disease

    PubMed Central

    Nestrasil, I.; Michaeli, S.; Liimatainen, T.; Rydeen, C. E.; Kotz, C. M.; Nixon, J. P.; Hanson, T.

    2011-01-01

    Prior work has shown that adiabatic T1ρ and T2ρ relaxation time constants may have sensitivity to cellular changes and the presence of iron, respectively, in Parkinson’s disease (PD). Further understanding of these magnetic resonance imaging (MRI) methods and how they relate to measures of disease severity and progression in PD is needed. Using T1ρand T2ρ on a 4T MRI scanner, we assessed the substantia nigra (SN) of nine non-demented moderately affected PD and ten gender- and age-matched control participants. When compared to controls, the SN of PD subjects had increased T1ρ and reduced T2ρ We also found a significant correlation between asymmetric motor features and asymmetry based on T1ρ. This study provides additional validation of T1ρ and T2ρ as a means to separate PD from control subjects, and T1ρ may be a useful marker of asymmetry in PD. PMID:20058018

  6. Zonal T2* and T1Gd assessment of knee joint cartilage in various histological grades of cartilage degeneration: an observational in vitro study

    PubMed Central

    Bittersohl, Bernd; Hosalkar, Harish S; Miese, Falk R; Schibensky, Jonas; König, Dietmar P; Herten, Monika; Antoch, Gerald; Krauspe, Rüdiger; Zilkens, Christoph

    2015-01-01

    Objectives Accurate assessment of cartilage status is increasingly becoming important to clinicians for offering joint preservation surgeries versus joint replacements. The goal of this study was to evaluate the validity of three-dimensional (3D), gradient-echo (GRE)-based T2* and T1Gd mapping for the assessment of various histological severities of degeneration in knee joint cartilage with potential implications for clinical management. Methods MRI and histological assessment were conducted in 36 ex vivo lateral femoral condyle specimens. The MRI protocol included a 3D GRE multiecho data image combination sequence in order to assess the T2* decay, a 3D double-echo steady-state sequence for assessment of cartilage morphology, and a dual flip angle 3D GRE sequence with volumetric interpolated breathhold examination for the T1Gd assessment. The histological sample analysis was performed according to the Mankin system. The data were then analysed statistically and correlated. Results We observed a significant decrease in the T2* and T1Gd values with increasing grades of cartilage degeneration (p<0.001) and a moderate correlation between T2* (r=0.514)/T1Gd (r=0.556) and the histological grading of cartilage degeneration (p<0.001). In addition, we noted a zonal variation in the T2* and T1Gd values reflecting characteristic zonal differences in the biochemical composition of hyaline cartilage. Conclusions This study outlines the potential of GRE-based T2* and T1Gd mapping to identify various grades of cartilage damage. Early changes in specific zones may assist clinicians in identifying methods of early intervention involving the targeted joint preservation approach versus moving forward with unicompartmental, bicompartmental or tricompartmental joint replacement procedures. Trial registration number DRKS00000729. PMID:25667150

  7. Fast pseudo-CT synthesis from MRI T1-weighted images using a patch-based approach

    NASA Astrophysics Data System (ADS)

    Torrado-Carvajal, A.; Alcain, E.; Montemayor, A. S.; Herraiz, J. L.; Rozenholc, Y.; Hernandez-Tamames, J. A.; Adalsteinsson, E.; Wald, L. L.; Malpica, N.

    2015-12-01

    MRI-based bone segmentation is a challenging task because bone tissue and air both present low signal intensity on MR images, making it difficult to accurately delimit the bone boundaries. However, estimating bone from MRI images may allow decreasing patient ionization by removing the need of patient-specific CT acquisition in several applications. In this work, we propose a fast GPU-based pseudo-CT generation from a patient-specific MRI T1-weighted image using a group-wise patch-based approach and a limited MRI and CT atlas dictionary. For every voxel in the input MR image, we compute the similarity of the patch containing that voxel with the patches of all MR images in the database, which lie in a certain anatomical neighborhood. The pseudo-CT is obtained as a local weighted linear combination of the CT values of the corresponding patches. The algorithm was implemented in a GPU. The use of patch-based techniques allows a fast and accurate estimation of the pseudo-CT from MR T1-weighted images, with a similar accuracy as the patient-specific CT. The experimental normalized cross correlation reaches 0.9324±0.0048 for an atlas with 10 datasets. The high NCC values indicate how our method can accurately approximate the patient-specific CT. The GPU implementation led to a substantial decrease in computational time making the approach suitable for real applications.

  8. 4(1H)-Pyridone and 4(1H)-Quinolone Derivatives as Antimalarials with Erythrocytic, Exoerythrocytic, and Transmission Blocking Activities

    PubMed Central

    Monastyrskyi, Andrii; Kyle, Dennis E.; Manetsch, Roman

    2015-01-01

    Infectious diseases are the second leading cause of deaths in the world with malaria being responsible for approximately the same amount of deaths as cancer in 2012. Despite the success in malaria prevention and control measures decreasing the disease mortality rate by 45% since 2000, the development of single-dose therapeutics with radical cure potential is required to completely eradicate this deadly condition. Targeting multiple stages of the malaria parasite is becoming a primary requirement for new candidates in antimalarial drug discovery and development. Recently, 4(1H)-pyridone, 4(1H)-quinolone, 1,2,3,4-tetrahydroacridone, and phenoxyethoxy-4(1H)-quinolone chemotypes have been shown to be antimalarials with blood stage activity, liver stage activity, and transmission blocking activity. Advancements in structure-activity relationship and structure-property relationship studies, biological evaluation in vitro and in vivo, as well as pharmacokinetics of the 4(1H)-pyridone and 4(1H)-quinolone chemotypes will be discussed. PMID:25116582

  9. Automated structure verification based on a combination of 1D (1)H NMR and 2D (1)H - (13)C HSQC spectra.

    PubMed

    Golotvin, Sergey S; Vodopianov, Eugene; Pol, Rostislav; Lefebvre, Brent A; Williams, Antony J; Rutkowske, Randy D; Spitzer, Timothy D

    2007-10-01

    A method for structure validation based on the simultaneous analysis of a 1D (1)H NMR and 2D (1)H - (13)C single-bond correlation spectrum such as HSQC or HMQC is presented here. When compared with the validation of a structure by a 1D (1)H NMR spectrum alone, the advantage of including a 2D HSQC spectrum in structure validation is that it adds not only the information of (13)C shifts, but also which proton shifts they are directly coupled to, and an indication of which methylene protons are diastereotopic. The lack of corresponding peaks in the 2D spectrum that appear in the 1D (1)H spectrum, also gives a clear picture of which protons are attached to heteroatoms. For all these benefits, combined NMR verification was expected and found by all metrics to be superior to validation by 1D (1)H NMR alone. Using multiple real-life data sets of chemical structures and the corresponding 1D and 2D data, it was possible to unambiguously identify at least 90% of the correct structures. As part of this test, challenging incorrect structures, mostly regioisomers, were also matched with each spectrum set. For these incorrect structures, the false positive rate was observed as low as 6%. PMID:17694570

  10. Preparation, GIAO NMR Calculations and Acidic Properties of Some Novel 4,5-dihydro-1H-1,2,4-triazol-5-one Derivatives with Their Antioxidant Activities

    PubMed Central

    Yüksek, Haydar; Alkan, Muzaffer; Cakmak, Ismail; Ocak, Zafer; Bahçeci, Şule; Calapoğlu, Mustafa; Elmastaş, Mahfuz; Kolomuç, Ali; Aksu, Havva

    2008-01-01

    Six novel 3-alkyl(aryl)-4-(p-nitrobenzoylamino)-4,5-dihydro-1H-1,2,4-triazol-5- ones (2a-f) were synthesized by the reactions of 3-alkyl(aryl)-4-amino-4,5-dihydro-1H- 1,2,4-triazol-5-ones (1a-f) with p-nitrobenzoyl chloride and characterized by elemental analyses and IR, 1H-NMR, 13C-NMR and UV spectral data. The newly synthesized compounds 2 were titrated potentiometrically with tetrabutylammonium hydroxide in four non-aqueous solvents such as acetone, isopropyl alcohol, tert-butyl alcohol and N,N-dimethylformamide, and the half-neutralization potential values and the corresponding pKa values were determined for all cases. Thus, the effects of solvents and molecular structure upon acidity were investigated. In addition, isotropic 1H and 13C nuclear magnetic shielding constants of compounds 2 were obtained by the gauge-including-atomic-orbital (GIAO) method at the B3LYP density functional level. The geometry of each compound has been optimized using the 6-311G basis set. Theoretical values were compared to the experimental data. Furthermore, these new compounds and five recently reported 3-alkyl-4-(2-furoylamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones (3a–c,e,f) were screened for their antioxidant activities. PMID:19325716

  11. Valuing Essays: Essaying Values

    ERIC Educational Resources Information Center

    Badley, Graham

    2010-01-01

    The essay regularly comes under attack. It is criticised for being rigidly linear rather than flexible and reflective. I first challenge this view by examining reasons why the essay should be valued as an important genre. Secondly, I propose that in using the essay form students and academics necessarily exemplify their own critical values. Essays…

  12. Caffeine intake inverts the effect of adenosine on myocardial perfusion during stress as measured by T1 mapping.

    PubMed

    Kuijpers, Dirkjan; Prakken, Niek H; Vliegenthart, Rozemarijn; van Dijkman, Paul R M; van der Harst, Pim; Oudkerk, Matthijs

    2016-10-01

    Caffeine intake before adenosine stress myocardial perfusion imaging may cause false negative findings. We hypothesized that the antagonistic effect of caffeine can be measured by T1 relaxation times in rest and adenosine stress cardiac magnetic resonance imaging (CMR), as T1 mapping techniques are sensitive to changes in myocardial blood volume. We prospectively analyzed 105 consecutive patients with adenosine stress perfusion CMR on a 1.5-T MRI system. Rest and stress T1 mapping was performed using Modified Look-Locker Inversion recovery. T1 reactivity was defined as difference in T1rest and T1stress (∆T1). Fifteen patients drank coffee within 4 h of CMR (<4H caffeine group), and 10 patients had coffee the day before (>8H caffeine group). Comparison was made to patients without self-reported coffee intake: 50 with normal CMR (control group), 18 with myocardial ischemia, and 12 with myocardial infarction. The national review board approved the study; all patients gave written informed consent. The <4H caffeine group showed inverted ∆T1 of -7.8 % (T1rest 975 ± 42 ms, T1stress 898 ± 51 ms, p < 0.0005). The >8H caffeine group showed reduced T1 reactivity (1.8 %; T1rest 979 ms, T1stress 997 ms) compared to the controls (4.3 %; T1rest 977 ± 40 ms, T1stress 1018 ± 40 ms), p < 0.0005. Ischemic and infarcted myocardium showed minimal T1 reactivity (0.2 and 0.3 %, respectively). Caffeine intake inverts the adenosine effect during stress perfusion CMR as measured by T1 mapping. T1 reactivity can assess the adequacy of adenosine-induced stress in perfusion CMR. PMID:27473274

  13. Surgical management of stage T1 renal tumours at Canadian academic centres

    PubMed Central

    Lavallée, Luke T.; Tanguay, Simon; Jewett, Michael A.; Wood, Lori; Kapoor, Anil; Rendon, Ricardo A.; Moore, Ronald B.; Lacombe, Louis; Kawakami, Jun; Pautler, Stephen E.; Drachenberg, Darrel E.; Black, Peter C.; Lattouf, Jean-Baptiste; Morash, Christopher; Cagiannos, Ilias; Liu, Zhihui; Breau, Rodney H.

    2015-01-01

    Introduction: The proportion of patients with stage 1 renal tumours receiving partial nephrectomy is considered a quality of care indicator. The objective of this study was to characterize surgical practice patterns at Canadian academic institutions for the treatment of these tumours. Methods: The Canadian Kidney Cancer Information System (CKCis) is a multicentre collaboration of 13 academic institutions in Canada. All patients with pathologic stage T1 renal tumours in CKCis were identified. Descriptive statistics were performed to characterize practice patterns over time. Associations between patient, tumour, and treatment factors with the use of partial nephrectomy were determined. Results: From 1988 to April 2014, 1453 patients with pathologic stage 1 renal tumours were entered in the CKCis database. Of these, 977 (67%) patients had pT1a tumours; of these, 765 (78%) received partial nephrectomy. Of the total number of patients (1453), 476 (33%) had pT1b tumours; of these, 204 (43%) received partial nephrectomy. The use of partial nephrectomy increased over time from 60% to 90% for pT1a tumours and 20% to 60% for pT1b tumours. Stage pT1b (relative risk [RR] 0.56, 95% confidence interval [CI] 0.50–0.63) and minimally invasive surgical approach (RR 0.78, 95% CI 0.73–0.84 for pT1a and RR 0.23, 95% CI 0.17–0.30 for pT1b) were associated with decreased use of partial nephrectomy. Most patient factors including age, gender, body mass index, hypertension, and renal function were not significantly associated with use of partial nephrectomy (p > 0.05). Conclusion: Almost all pT1a and most pT1b renal tumours managed surgically at academic centres in Canada receive partial nephrectomy. The use of partial versus radical nephrectomy appears to occur independently of patient age and comorbid status, which may indicate that urologists are performing partial nephrectomy whenever technically feasible based on tumour factors. Although the ideal proportion patients receiving

  14. Stereospecificity of (1) H, (13) C and (15) N shielding constants in the isomers of methylglyoxal bisdimethylhydrazone: problem with configurational assignment based on (1) H chemical shifts.

    PubMed

    Afonin, Andrei V; Pavlov, Dmitry V; Ushakov, Igor A; Keiko, Natalia A

    2012-07-01

    In the (13) C NMR spectra of methylglyoxal bisdimethylhydrazone, the (13) C-5 signal is shifted to higher frequencies, while the (13) C-6 signal is shifted to lower frequencies on going from the EE to ZE isomer following the trend found previously. Surprisingly, the (1) H-6 chemical shift and (1) J(C-6,H-6) coupling constant are noticeably larger in the ZE isomer than in the EE isomer, although the configuration around the -CH═N- bond does not change. This paradox can be rationalized by the C-H⋯N intramolecular hydrogen bond in the ZE isomer, which is found from the quantum-chemical calculations including Bader's quantum theory of atoms in molecules analysis. This hydrogen bond results in the increase of δ((1) H-6) and (1) J(C-6,H-6) parameters. The effect of the C-H⋯N hydrogen bond on the (1) H shielding and one-bond (13) C-(1) H coupling complicates the configurational assignment of the considered compound because of these spectral parameters. The (1) H, (13) C and (15) N chemical shifts of the 2- and 8-(CH(3) )(2) N groups attached to the -C(CH(3) )═N- and -CH═N- moieties, respectively, reveal pronounced difference. The ab initio calculations show that the 8-(CH(3) )(2) N group conjugate effectively with the π-framework, and the 2-(CH(3) )(2) N group twisted out from the plane of the backbone and loses conjugation. As a result, the degree of charge transfer from the N-2- and N-8- nitrogen lone pairs to the π-framework varies, which affects the (1) H, (13) C and (15) N shieldings. PMID:22615146

  15. The complete genome sequence of the Arcobacter butzleri cattle isolate 7h1h

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arcobacter butzleri strain 7h1h was isolated in the UK from a clinically healthy dairy cow. The genome of this isolate was sequenced to completion. Here we present the annotation and analysis of the completed 7h1h genome, as well as comparison of this genome to the existing A. butzleri RM4018 and ED...

  16. Comparison of accelerated T1-weighted whole-brain structural-imaging protocols.

    PubMed

    Falkovskiy, Pavel; Brenner, Daniel; Feiweier, Thorsten; Kannengiesser, Stephan; Maréchal, Bénédicte; Kober, Tobias; Roche, Alexis; Thostenson, Kaely; Meuli, Reto; Reyes, Denise; Stoecker, Tony; Bernstein, Matt A; Thiran, Jean-Philippe; Krueger, Gunnar

    2016-01-01

    Imaging in neuroscience, clinical research and pharmaceutical trials often employs the 3D magnetisation-prepared rapid gradient-echo (MPRAGE) sequence to obtain structural T1-weighted images with high spatial resolution of the human brain. Typical research and clinical routine MPRAGE protocols with ~1mm isotropic resolution require data acquisition time in the range of 5-10min and often use only moderate two-fold acceleration factor for parallel imaging. Recent advances in MRI hardware and acquisition methodology promise improved leverage of the MR signal and more benign artefact properties in particular when employing increased acceleration factors in clinical routine and research. In this study, we examined four variants of a four-fold-accelerated MPRAGE protocol (2D-GRAPPA, CAIPIRINHA, CAIPIRINHA elliptical, and segmented MPRAGE) and compared clinical readings, basic image quality metrics (SNR, CNR), and automated brain tissue segmentation for morphological assessments of brain structures. The results were benchmarked against a widely-used two-fold-accelerated 3T ADNI MPRAGE protocol that served as reference in this study. 22 healthy subjects (age=20-44yrs.) were imaged with all MPRAGE variants in a single session. An experienced reader rated all images of clinically useful image quality. CAIPIRINHA MPRAGE scans were perceived on average to be of identical value for reading as the reference ADNI-2 protocol. SNR and CNR measurements exhibited the theoretically expected performance at the four-fold acceleration. The results of this study demonstrate that the four-fold accelerated protocols introduce systematic biases in the segmentation results of some brain structures compared to the reference ADNI-2 protocol. Furthermore, results suggest that the increased noise levels in the accelerated protocols play an important role in introducing these biases, at least under the present study conditions. PMID:26297848

  17. Detection of Lesions Underlying Intractable Epilepsy on T1-Weighted MRI as an Outlier Detection Problem.

    PubMed

    El Azami, Meriem; Hammers, Alexander; Jung, Julien; Costes, Nicolas; Bouet, Romain; Lartizien, Carole

    2016-01-01

    Pattern recognition methods, such as computer aided diagnosis (CAD) systems, can help clinicians in their diagnosis by marking abnormal regions in an image. We propose a machine learning system based on a one-class support vector machine (OC-SVM) classifier for the detection of abnormalities in magnetic resonance images (MRI) applied to patients with intractable epilepsy. The system learns the features associated with healthy control subjects, allowing a voxelwise assessment of the deviation of a test subject pattern from the learned patterns. While any number of various features can be chosen and learned, here we focus on two texture parameters capturing image patterns associated with epileptogenic lesions on T1-weighted brain MRI e.g. heterotopia and blurred junction between the grey and white matter. The CAD output consists of patient specific 3D maps locating clusters of suspicious voxels ranked by size and degree of deviation from control patterns. System performance was evaluated using realistic simulations of challenging detection tasks as well as clinical data of 77 healthy control subjects and of eleven patients (13 lesions). It was compared to that of a mass univariate statistical parametric mapping (SPM) single subject analysis based on the same set of features. For all simulations, OC-SVM yielded significantly higher values of the area under the ROC curve (AUC) and higher sensitivity at low false positive rate. For the clinical data, both OC-SVM and SPM successfully detected 100% of the lesions in the MRI positive cases (3/13). For the MRI negative cases (10/13), OC-SVM detected 7/10 lesions and SPM analysis detected 5/10 lesions. In all experiments, OC-SVM produced fewer false positive detections than SPM. OC-SVM may be a versatile system for unbiased lesion detection. PMID:27603778

  18. A classical approach in simple nuclear fusion reaction {sub 1}H{sup 2}+{sub 1}H{sup 3} using two-dimension granular molecular dynamics model

    SciTech Connect

    Viridi, S.; Kurniadi, R.; Waris, A.; Perkasa, Y. S.

    2012-06-06

    Molecular dynamics in 2-D accompanied by granular model provides an opportunity to investigate binding between nuclei particles and its properties that arises during collision in a fusion reaction. A fully classical approach is used to observe the influence of initial angle of nucleus orientation to the product yielded by the reaction. As an example, a simplest fusion reaction between {sub 1}H{sup 2} and {sub 1}H{sup 3} is observed. Several products of the fusion reaction have been obtained, even the unreported ones, including temporary {sub 2}He{sup 4} nucleus.

  19. 4T1 Murine Mammary Carcinoma Cells Enhance Macrophage-Mediated Innate Inflammatory Responses

    PubMed Central

    Madera, Laurence; Greenshields, Anna; Coombs, Melanie R. Power; Hoskin, David W.

    2015-01-01

    Tumor progression and the immune response are intricately linked. While it is known that cancers alter macrophage inflammatory responses to promote tumor progression, little is known regarding how cancers affect macrophage-dependent innate host defense. In this study, murine bone-marrow-derived macrophages (BMDM) were exposed to murine carcinoma-conditioned media prior to assessment of the macrophage inflammatory response. BMDMs exposed to 4T1 mammary carcinoma-conditioned medium demonstrated enhanced production of pro-inflammatory cytokines tumor necrosis factor α, interleukin-6, and CCL2 in response to lipopolysaccharide (LPS) while production of interleukin-10 remained unchanged. The increased LPS-induced production of pro-inflammatory cytokines was transient and correlated with enhanced cytokine production in response to other Toll-like receptor agonists, including peptidoglycan and flagellin. In addition, 4T1-conditioned BMDMs exhibited strengthened LPS-induced nitric oxide production and enhanced phagocytosis of Escherichia coli. 4T1-mediated augmentation of macrophage responses to LPS was partially dependent on the NFκB pathway, macrophage-colony stimulating factor, and actin polymerization, as well as the presence of 4T1-secreted extracellular vesicles. Furthermore, peritoneal macrophages obtained from 4T1 tumor-bearing mice displayed enhanced pro-inflammatory cytokine production in response to LPS. These results suggest that uptake of 4T1-secreted factors and actin-mediated ingestion of 4T1-secreted exosomes by macrophages cause a transient enhancement of innate inflammatory responses. Mammary carcinoma-mediated regulation of innate immunity may have significant implications for our understanding of host defense and cancer progression. PMID:26177198

  20. 4T1 Murine Mammary Carcinoma Cells Enhance Macrophage-Mediated Innate Inflammatory Responses.

    PubMed

    Madera, Laurence; Greenshields, Anna; Coombs, Melanie R Power; Hoskin, David W

    2015-01-01

    Tumor progression and the immune response are intricately linked. While it is known that cancers alter macrophage inflammatory responses to promote tumor progression, little is known regarding how cancers affect macrophage-dependent innate host defense. In this study, murine bone-marrow-derived macrophages (BMDM) were exposed to murine carcinoma-conditioned media prior to assessment of the macrophage inflammatory response. BMDMs exposed to 4T1 mammary carcinoma-conditioned medium demonstrated enhanced production of pro-inflammatory cytokines tumor necrosis factor α, interleukin-6, and CCL2 in response to lipopolysaccharide (LPS) while production of interleukin-10 remained unchanged. The increased LPS-induced production of pro-inflammatory cytokines was transient and correlated with enhanced cytokine production in response to other Toll-like receptor agonists, including peptidoglycan and flagellin. In addition, 4T1-conditioned BMDMs exhibited strengthened LPS-induced nitric oxide production and enhanced phagocytosis of Escherichia coli. 4T1-mediated augmentation of macrophage responses to LPS was partially dependent on the NFκB pathway, macrophage-colony stimulating factor, and actin polymerization, as well as the presence of 4T1-secreted extracellular vesicles. Furthermore, peritoneal macrophages obtained from 4T1 tumor-bearing mice displayed enhanced pro-inflammatory cytokine production in response to LPS. These results suggest that uptake of 4T1-secreted factors and actin-mediated ingestion of 4T1-secreted exosomes by macrophages cause a transient enhancement of innate inflammatory responses. Mammary carcinoma-mediated regulation of innate immunity may have significant implications for our understanding of host defense and cancer progression. PMID:26177198

  1. VGluT1+ Neuronal Glutamatergic Signaling Regulates Postnatal Developmental Maturation of Cortical Protoplasmic Astroglia

    PubMed Central

    Morel, Lydie; Higashimori, Haruki; Tolman, Michaela

    2014-01-01

    Functional maturation of astroglia is characterized by the development of a unique, ramified morphology and the induction of important functional proteins, such as glutamate transporter GLT1. Although pathways regulating the early fate specification of astroglia have been characterized, mechanisms regulating postnatal maturation of astroglia remain essentially unknown. Here we used a new in vivo approach to illustrate and quantitatively analyze developmental arborization of astroglial processes. Our analysis found a particularly high increase in the number of VGluT1+ neuronal glutamatergic synapses that are ensheathed by processes from individual developing astroglia from postnatal day (P) 14 to P26, when astroglia undergo dramatic postnatal maturation. Subsequent silencing of VGluT1+ synaptic activity in VGluT1 KO mice significantly reduces astroglial domain growth and the induction of GLT1 in the cortex, but has no effect on astroglia in the hypothalamus, where non-VGluT1+ synaptic signaling predominates. In particular, electron microscopy analysis showed that the loss of VGluT1+ synaptic signaling significantly decreases perisynaptic enshealthing of astroglial processes on synapses. To further determine whether synaptically released glutamate mediates VGluT1+ synaptic signaling, we pharmacologically inhibited and genetically ablated metabotropic glutamate receptors (mGluRs, especially mGluR5) in developing cortical astroglia and found that developmental arborization of astroglial processes and expression of functional proteins, such as GLT1, is significantly decreased. In summary, our genetic analysis provides new in vivo evidence that VGluT1+ glutamatergic signaling, mediated by the astroglial mGluR5 receptor, regulates the functional maturation of cortical astroglia during development. These results elucidate a new mechanism for regulating the developmental formation of functional neuron-glia synaptic units. PMID:25122895

  2. Involvement of glucocorticoid in induction of lingual T1R3 in rodents.

    PubMed

    Ogawa, Nobuhumi; Kanki, Keita; Honda, Kotaro; Tomooka, Yasuhiro; Ryoke, Kazuo; Watanabe, Tatsuo

    2015-08-15

    We previously reported that in rats, chronic exposure to stress inhibits the induction of the common receptor (T1R3) for sweet and umami tastes. Here, we investigated whether endogenous glucocorticoids (GCs) might be responsible for this inhibition. In addition, we used mouse taste-bud cells (TB cells) expressing T1R3 to examine the effect of exogenous GC on T1R3 induction. Both adrenal glands were removed from rats [adrenalectomized (ADX) rats] and T1R3 mRNA expression in fungiform papillae was examined by real-time RT-PCR. T1R3 mRNA expression was significantly reduced in the ADX rats (versus sham-ADX rats). The reduced mRNA expression was restored to the level seen in the sham-ADX rats by administration of dexamethasone (DEX) at the smallest dose tested (0.1ng/kg, i.p.). However, with larger doses of DEX (10 and 1000ng/kg, i.p.) there was no such restoration (i.e., the expression level did not differ from that seen in ADX rats). Expression of the mRNA for the GC receptor-α was detected in mouse TB cells by RT-PCR. Significantly reduced T1R3 mRNA expression, as measured by real-time RT-PCR, was observed in TB cells at 24h after application of DEX (0.1, 1.0, or 10μM). These results suggest that in rodents: (a) a low concentration of endogenous GC is necessary and sufficient for induction of T1R3 expression, and that higher concentrations may actually inhibit such induction, and (b) this inhibitory effect may be due, at least in part, to a direct action of GC on taste cells. PMID:26096555

  3. Crystallographic structure of the T=1 particle of brome mosaic virus.

    PubMed

    Larson, Steven B; Lucas, Robert W; McPherson, Alexander

    2005-02-25

    T=1 icosahedral particles of amino terminally truncated brome mosaic virus (BMV) protein were created by treatment of the wild-type T=3 virus with 1M CaCl2 and crystallized from sodium malonate. Diffraction data were collected from frozen crystals to beyond 2.9 A resolution and the structure determined by molecular replacement and phase extension. The particles are composed of pentameric capsomeres from the wild-type virions which have reoriented with respect to the original particle pentameric axes by rotations of 37 degrees , and formed tenuous interactions with one another, principally through conformationally altered C-terminal polypeptides. Otherwise, the pentamers are virtually superimposable upon those of the original T=3 BMV particles. The T=1 particles, in the crystals, are not perfect icosahedra, but deviate slightly from exact symmetry, possibly due to packing interactions. This suggests that the T=1 particles are deformable, which is consistent with the loose arrangement of pentamers and latticework of holes that penetrate the surface. Atomic force microscopy showed that the T=3 to T=1 transition could occur by shedding of hexameric capsomeres and restructuring of remaining pentamers accompanied by direct condensation. Knowledge of the structures of the BMV wild-type and T=1 particles now permit us to propose a tentative model for that process. A comparison of the BMV T=1 particles was made with the reassembled T=1 particles produced from the coat protein of trypsin treated alfalfa mosaic virus (AlMV), another bromovirus. There is little resemblance between the two particles. The BMV particle, with a maximum diameter of 195 A, is made from distinctive pentameric capsomeres with large holes along the 3-fold axis, while the AlMV particle, of approximate maximum diameter 220 A, has subunits closely packed around the 3-fold axis, large holes along the 5-fold axis, and few contacts within pentamers. In both particles crucial linkages are made about

  4. Separation of the longitudinal and transverse cross sections in the {sup 1}H(e,e{prime} K{sup +}){Lambda} and {sup 1}H(e,e{prime} K{sup +}){Sigma}{sup 0} reactions

    SciTech Connect

    R.M. Mohring; David Abbott; Abdellah Ahmidouch; Thomas Amatuni; Pawel Ambrozewicz; Tatiana Angelescu; Christopher Armstrong; John Arrington; Ketevi Assamagan; Steven Avery; Kevin Bailey; Kevin Beard; S Beedoe; Elizabeth Beise; Herbert Breuer; Roger Carlini; Jinseok Cha; C. Chang; Nicholas Chant; Evaristo Cisbani; Glenn Collins; William Cummings; Samuel Danagoulian; Raffaele De Leo; Fraser Duncan; James Dunne; Dipangkar Dutta; T Eden; Rolf Ent; Laurent Eyraud; Lars Ewell; John Finn; H. Terry Fortune; Valera Frolov; Salvatore Frullani; Christophe Furget; Franco Garibaldi; David Gaskell; Donald Geesaman; Paul Gueye; Kenneth Gustafsson; Jens-Ole Hansen; Mark Harvey; Wendy Hinton; Ed Hungerford; Mauro Iodice; Ceasar Jackson; Cynthia Keppel; Wooyoung Kim; Kouichi Kino; Douglas Koltenuk; Serge Kox; Laird Kramer; Antonio Leone; Allison Lung; David Mack; Richard Madey; M Maeda; Stanislaw Majewski; Pete Markowitz; T Mart; C Martoff; David Meekins; A. Mihul; Joseph Mitchell; Hamlet Mkrtchyan; Sekazi Mtingwa; Maria-Ioana Niculescu; R. Perrino; David Potterveld; John Price; Brian Raue; Jean Sebastien Real; Joerg Reinhold; Philip Roos; Teijiro Saito; Geoff Savage; Reyad Sawafta; Ralph Segel; Stepan Stepanyan; Paul Stoler; Vardan Tadevosyan; Liguang Tang; Liliana Teodorescu; Tatsuo Terasawa; Hiroaki Tsubota; Guido Urciuoli; Jochen Volmer; William Vulcan; T. Welch; Robert Williams; Stephen Wood; Chen Yan; Benjamin Zeidman

    2003-05-19

    We report measurements of cross sections for the reaction {sup 1}H(e,e{prime} K{sup +})Y, for both the {Lambda} and {Sigma}{sup 0} hyperon states, at an invariant mass of W = 1.84 GeV and four-momentum transfers 0.5 < Q{sup 2} < 2 (GeV/c){sup 2}. Data were taken for three values of virtual photon polarization {epsilon}, allowing the decomposition of the cross sections into longitudinal and transverse components. The {Lambda} data are a revised analysis of prior work, whereas the {Sigma}{sup 0} results have not been previously reported.

  5. Orally Bioavailable 6-Chloro-7-methoxy-4(1H)-quinolones Efficacious against Multiple Stages of Plasmodium

    PubMed Central

    2015-01-01

    The continued proliferation of malaria throughout temperate and tropical regions of the world has promoted a push for more efficacious treatments to combat the disease. Unfortunately, more recent remedies such as artemisinin combination therapies have been rendered less effective due to developing parasite resistance, and new drugs are required that target the parasite in the liver to support the disease elimination efforts. Research was initiated to revisit antimalarials developed in the 1940s and 1960s that were deemed unsuitable for use as therapeutic agents as a result of poor understanding of both physicochemical properties and parasitology. Structure–activity and structure–property relationship studies were conducted to generate a set of compounds with the general 6-chloro-7-methoxy-2-methyl-4(1H)-quinolone scaffold which were substituted at the 3-position with a variety of phenyl moieties possessing various properties. Extensive physicochemical evaluation of the quinolone series was carried out to downselect the most promising 4(1H)-quinolones, 7, 62, 66, and 67, which possessed low-nanomolar EC50 values against W2 and TM90-C2B as well as improved microsomal stability. Additionally, in vivo Thompson test results using Plasmodium berghei in mice showed that these 4(1H)-quinolones were efficacious for the reduction of parasitemia at >99% after 6 days. PMID:25148516

  6. Transcriptional regulation of α1H T-type calcium channel under hypoxia.

    PubMed

    Sellak, Hassan; Zhou, Chun; Liu, Bainan; Chen, Hairu; Lincoln, Thomas M; Wu, Songwei

    2014-10-01

    The low-voltage-activated T-type Ca(2+) channels play an important role in mediating the cellular responses to altered oxygen tension. Among three T-type channel isoforms, α1G, α1H, and α1I, only α1H was found to be upregulated under hypoxia. However, mechanisms underlying such hypoxia-dependent isoform-specific gene regulation remain incompletely understood. We, therefore, studied the hypoxia-dependent transcriptional regulation of α1G and α1H gene promoters with the aim to identify the functional hypoxia-response elements (HREs). In rat pulmonary artery smooth muscle cells (PASMCs) and pheochromocytoma (PC12) cells after hypoxia (3% O2) exposure, we observed a prominent increase in α1H mRNA at 12 h along with a significant rise in α1H-mediated T-type current at 24 and 48 h. We then cloned two promoter fragments from the 5'-flanking regions of rat α1G and α1H gene, 2,000 and 3,076 bp, respectively, and inserted these fragments into a luciferase reporter vector. Transient transfection of PASMCs and PC12 cells with these recombinant constructs and subsequent luciferase assay revealed a significant increase in luciferase activity from the reporter containing the α1H, but not α1G, promoter fragment under hypoxia. Using serial deletion and point mutation analysis strategies, we identified a functional HRE at site -1,173cacgc-1,169 within the α1H promoter region. Furthermore, an electrophoretic mobility shift assay using this site as a DNA probe demonstrated an increased binding activity to nuclear protein extracts from the cells after hypoxia exposure. Taken together, these findings indicate that hypoxia-induced α1H upregulation involves binding of hypoxia-inducible factor to an HRE within the α1H promoter region. PMID:25099734

  7. Transcriptional regulation of α1H T-type calcium channel under hypoxia

    PubMed Central

    Sellak, Hassan; Zhou, Chun; Liu, Bainan; Chen, Hairu; Lincoln, Thomas M.

    2014-01-01

    The low-voltage-activated T-type Ca2+ channels play an important role in mediating the cellular responses to altered oxygen tension. Among three T-type channel isoforms, α1G, α1H, and α1I, only α1H was found to be upregulated under hypoxia. However, mechanisms underlying such hypoxia-dependent isoform-specific gene regulation remain incompletely understood. We, therefore, studied the hypoxia-dependent transcriptional regulation of α1G and α1H gene promoters with the aim to identify the functional hypoxia-response elements (HREs). In rat pulmonary artery smooth muscle cells (PASMCs) and pheochromocytoma (PC12) cells after hypoxia (3% O2) exposure, we observed a prominent increase in α1H mRNA at 12 h along with a significant rise in α1H-mediated T-type current at 24 and 48 h. We then cloned two promoter fragments from the 5′-flanking regions of rat α1G and α1H gene, 2,000 and 3,076 bp, respectively, and inserted these fragments into a luciferase reporter vector. Transient transfection of PASMCs and PC12 cells with these recombinant constructs and subsequent luciferase assay revealed a significant increase in luciferase activity from the reporter containing the α1H, but not α1G, promoter fragment under hypoxia. Using serial deletion and point mutation analysis strategies, we identified a functional HRE at site −1,173cacgc−1,169 within the α1H promoter region. Furthermore, an electrophoretic mobility shift assay using this site as a DNA probe demonstrated an increased binding activity to nuclear protein extracts from the cells after hypoxia exposure. Taken together, these findings indicate that hypoxia-induced α1H upregulation involves binding of hypoxia-inducible factor to an HRE within the α1H promoter region. PMID:25099734

  8. Rapid assessment of quantitative T1, T2 and T2* in lower extremity muscles in response to maximal treadmill exercise.

    PubMed

    Varghese, Juliet; Scandling, Debbie; Joshi, Rohit; Aneja, Ashish; Craft, Jason; Raman, Subha V; Rajagopalan, Sanjay; Simonetti, Orlando P; Mihai, Georgeta

    2015-08-01

    MRI provides a non-invasive diagnostic platform to quantify the physical and physiological attributes of skeletal muscle at rest and in response to exercise. MR relaxation parameters (T1, T2 and T2*) are characteristic of tissue composition and metabolic properties. With the recent advent of quantitative techniques that allow rapid acquisition of T1, T2 and T2* maps, we posited that an integrated treadmill exercise-quantitative relaxometry paradigm can rapidly characterize exercise-induced changes in skeletal muscle relaxation parameters. Accordingly, we investigated the rest/recovery kinetics of T1, T2 and T2* in response to treadmill exercise in the anterior tibialis, soleus and gastrocnemius muscles of healthy volunteers, and the relationship of these parameters to age and gender. Thirty healthy volunteers (50.3 ± 16.6 years) performed the Bruce treadmill exercise protocol to maximal exhaustion. Relaxometric maps were sequentially acquired at baseline and for approximately 44 minutes post-exercise. Our results show that T1, T2 and T2* are significantly and differentially increased immediately post-exercise among the leg muscle groups, and these values recover to near baseline within 30-44 minutes. Our results demonstrate the potential to characterize the kinetics of relaxation parameters with quantitative mapping and upright exercise, providing normative values and some clarity on the impact of age and gender. PMID:26123219

  9. Quantitative (1)H NMR method for hydrolytic kinetic investigation of salvianolic acid B.

    PubMed

    Pan, Jianyang; Gong, Xingchu; Qu, Haibin

    2013-11-01

    This work presents an exploratory study for monitoring the hydrolytic process of salvianolic acid B (Sal B) in low oxygen condition using a simple quantitative (1)H NMR (Q-NMR) method. The quantity of the compounds was calculated by the relative ratio of the integral values of the target peak for each compound to the known amount of the internal standard trimethylsilyl propionic acid (TSP). Kinetic runs have been carried out on different initial concentrations of Sal B (5.00, 10.0, 20.0mg/mL) and temperatures of 70, 80, 90°C. The effect of these two factors during the transformation process of Sal B was investigated. The hydrolysis followed pseudo-first-order kinetics and the apparent degradation kinetic constant at 80°C decreased when concentration of Sal B increased. Under the given conditions, the rate constant of overall hydrolysis as a function of temperature obeyed the Arrhenius equation. Six degradation products were identified by NMR and mass spectrometric analysis. Four of these degradation products, i.e. danshensu (DSS), protocatechuic aldehyde (PRO), salvianolic acid D (Sal D) and lithospermic acid (LA) were further identified by comparing the retention times with standard compounds. The advantage of this Q-NMR method was that no reference compounds were required for calibration curves, the quantification could be directly realized on hydrolyzed samples. It was proved to be simple, convenient and accurate for hydrolytic kinetic study of Sal B. PMID:23867115

  10. Survey and qualification of internal standards for quantification by 1H NMR spectroscopy.

    PubMed

    Rundlöf, Torgny; Mathiasson, Marie; Bekiroglu, Somer; Hakkarainen, Birgit; Bowden, Tim; Arvidsson, Torbjörn

    2010-09-01

    In quantitative NMR (qNMR) selection of an appropriate internal standard proves to be crucial. In this study, 25 candidate compounds considered to be potent internal standards were investigated with respect to the ability of providing unique signal chemical shifts, purity, solubility, and ease of use. The (1)H chemical shift (delta) values, assignments, multiplicities and number of protons (for each signal), appropriateness (as to be used as internal standards) in four different deuterated solvents (D(2)O, DMSO-d(6), CD(3)OD, CDCl(3)) were studied. Taking into account the properties of these 25 internal standards, the most versatile eight compounds (2,4,6-triiodophenol, 1,3,5-trichloro-2-nitrobenzene, 3,4,5-trichloropyridine, dimethyl terephthalate, 1,4-dinitrobenzene, 2,3,5-triiodobenzoic acid, maleic acid and fumaric acid) were qualified using both differential scanning calorimetry (DSC) and NMR spectroscopy employing highly pure acetanilide as the reference standard. The data from these two methods were compared as well as utilized in the quality assessment of the compounds as internal standards. Finally, the selected internal standards were tested and evaluated in a real case of quantitative NMR analysis of a paracetamol pharmaceutical product. PMID:20207092

  11. Characterization of water-soluble organic matter in urban aerosol by 1H-NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Chalbot, Marie-Cecile G.; Chitranshi, Priyanka; Gamboa da Costa, Gonçalo; Pollock, Erik; Kavouras, Ilias G.

    2016-03-01

    The functional and 13C isotopic compositions of water-soluble organic carbon (WSOC) in atmospheric aerosol were determined by nuclear magnetic resonance (1H-NMR) and isotope ratio mass spectrometry (IRMS) in an urban location in the Southern Mississippi Valley. The origin of WSOC was resolved using the functional distribution of organic hydrogen, δ13C ratio, and positive matrix factorization (PMF). Three factors were retained based on NMR spectral bins loadings. Two factors (factors 1 and 3) demonstrated strong associations with the aliphatic region in the NMR spectra and levoglucosan resonances. Differences between the two factors included the abundance of the aromatic functional group for factor 1, indicating fresh emissions and, for factor 3, the presence of resonances attributed to secondary ammonium nitrate and low δ13C ratio values that are indicative of secondary organic aerosol. Factors 1 and 3 added 0.89 and 1.08 μgC m-3, respectively, with the highest contribution in the summer and fall. Factor 2 retained resonances consistent with saccharides and was attributed to pollen particles. Its contribution to WSOC varied from 0.22 μgC m-3 in winter to 1.04 μgC m-3 in spring.

  12. Experimental and DFT studies on the vibrational spectra of 1H-indene-2-boronic acid

    NASA Astrophysics Data System (ADS)

    Alver, Özgur; Kaya, Mehmet Fatih

    2014-11-01

    Stable conformers and geometrical molecular structures of 1H-indene-2-boronic acid (I-2B(OH)2) were studied experimentally and theoretically using FT-IR and FT-Raman spectroscopic methods. FT-IR and FT-Raman spectra were recorded in the region of 4000-400 cm-1, and 3700-400 cm-1, respectively. The optimized geometric structures were searched by Becke-3-Lee-Yang-Parr (B3LYP) hybrid density functional theory method with 6-31++G(d,p) basis set. Vibrational wavenumbers of I-2B(OH)2 were calculated using B3LYP density functional methods including 6-31++G(d,p) basis set. Experimental and theoretical results show that density functional B3LYP method gives satisfactory results for predicting vibrational wavenumbers except OH stretching modes which is probably due to increasing unharmonicity in the high wave number region and possible intra and inter molecular interaction at OH edges. To support the assigned vibrational wavenumbers, the potential energy distribution (PED) values were also calculated using VEDA 4 (Vibrational Energy Distribution Analysis) program.

  13. Gene therapy for hemophilia B mice with scAAV8-LP1-hFIX.

    PubMed

    Lu, Wei; Zhou, Qingzhang; Yang, Hao; Wang, Hao; Gu, Yexing; Shen, Qi; Xue, Jinglun; Dong, Xiaoyan; Chen, Jinzhong

    2016-06-01

    Hemophilia B is a hemorrhagic disease caused by the deficiency of clotting factor IX (FIX). Gene therapy might be the ultimate strategy for the disease. However, two main problems that should be solved in gene therapy for hemophilia B are immunity and safety. Self-complementary adeno-associated virus serotype 8 (scAAV8), a non-human primate AAV featuring low immunogenicity and high transfection efficiency in liver cells, might be a potential vector for hemophilia B gene therapy. A strong liver-specific promoter-1 (LP1) was inserted and mutant human FIX Arg338Ala was introduced into plasmid scAAV8-LP1 to develop an optimized AAV8 vector that expresses human clotting factor FIX (hFIX). The efficiency of scAAV8-LP1-hFIX administered through normal systemic injection or hydrodynamic injection was compared. A high expression was achieved using hydrodynamic injection, and the peak hFIX expression levels in the 5 × 10(11) and 1 × 10(11) virus genome (vg) cohorts were 31.94% and 25.02% of normal level, respectively, at 60 days post-injection. From the perspective of long-term (200 days) expression, both injection methods presented promising results with the concentration value maintained above 4% of normal plasma. The results were further verified by enzyme-linked immunosorbent assay and activated partial thromboplastin time. Our study provides a potential gene therapy method for hemophilia B. PMID:27052253

  14. Differential osmotic behavior of water components in living skeletal muscle resolved by 1H-NMR.

    PubMed

    Kimura, Masako; Takemori, Shigeru; Yamaguchi, Maki; Umazume, Yoshiki

    2005-08-01

    Using frog sartorius muscle, we observed transverse relaxation processes of (1)H-NMR signals from myowater. The process could be well described by four characteristic exponentials: the extremely slow exponential of relaxation time constant T(2) > 0.4 s, the slow one of T(2) approximately 0.15 s, the intermediate one of 0.03 s < T(2) < 0.06 s, and the rapid one of T(2) < 0.03 s. Addition of isotonic extracellular solution affected only the extremely slow exponential, linearly increasing its amplitude and gradually increasing its T(2) toward that of the bulk solution (1.7 s). Therefore, this exponential should represent extracellular surplus solution independently of the other exponentials. At two thirds to three times the isotonicity, the amplitude of the intermediate exponential showed normal osmotic behavior in parallel with the volume change of the myofilament lattice measured with x-ray diffraction. In the same tonicity range, the amplitude of the rapid exponential showed converse osmotic behavior. Lower tonicities increased the amplitude of only the slow exponential. Studied tonicities did not affect the T(2) values. The distinct osmotic behavior indicated that each characteristic exponential could be viewed as a distinct water group. In addition, the converse osmotic behavior suggested that the rapid exponential would not be a static water layer on the macromolecule surface. PMID:15894647

  15. Incidence and Predictors of Understaging in Patients with Clinical T1 Urothelial Carcinoma Undergoing Radical Cystectomy

    PubMed Central

    Ark, Jacob T.; Keegan, Kirk A.; Barocas, Daniel A.; Morgan, Todd M.; Resnick, Matthew J.; You, Chaochen; Cookson, Michael S.; Penson, David F.; Davis, Rodney; Clark, Peter E.; Smith, Joseph A.; Chang, Sam S.

    2013-01-01

    Summary Objective To evaluate predictors of understaging in patients with presumed non-muscle invasive bladder cancer (NMIBC) identified on transurethral resection of bladder tumor (TURBT) who underwent radical cystectomy (RC) with attention to the role of a restaging TURBT. Materials and Methods We retrospectively evaluated 279 consecutive patients with clinically staged T1 (cT1) disease following TURBT who underwent RC at our institution from April 2000 to July 2011. 60 of these cT1 patients had undergone a restaging TURBT prior to RC. The primary outcome measure was pathological staging of T2 or greater disease at the time of RC. Results 134 (48.0%) patients were understaged. Of the 60 patients who remained cT1 after a restaging TURBT, 28 (46.7%) were understaged. Solitary tumor (OR 0.43, 95% CI 0.25–0.76, p = 0.004) and fewer prior TURBTs (OR 0.84, 95% CI 0.71–1.00, p = 0.05) were independent risk factors for understaging. Conclusions Despite the overall improvement in staging accuracy linked to restaging TURBTs, the risk of clinical understaging remains high in restaged patients found to have persistent T1 urothelial carcinoma who undergo RC. Solitary tumor and fewer prior TURBTs are independent risk factors for being understaged. Incorporating these predictors into preoperative risk stratification may allow for augmented identification of those patients with clinical NMIBC who stand to benefit most from RC. PMID:24053444

  16. A Mathematical Model of T1D Acceleration and Delay by Viral Infection.

    PubMed

    Moore, James R; Adler, Fred

    2016-03-01

    Type 1 diabetes (T1D) is often triggered by a viral infection, but the T1D prevalence is rising among populations that have a lower exposure to viral infection. In an animal model of T1D, the NOD mouse, viral infection at different ages may either accelerate or delay disease depending on the age of infection and the type of virus. Viral infection may affect the progression of T1D via multiple mechanisms: triggering inflammation, bystander activation of self-reactive T-cells, inducing a competitive immune response, or inducing a regulatory immune response. In this paper, we create mathematical models of the interaction of viral infection with T1D progression, incorporating each of these four mechanisms. Our goal is to understand how each viral mechanism interacts with the age of infection. The model predicts that each viral mechanism has a unique pattern of interaction with disease progression. Viral inflammation always accelerates disease, but the effect decreases with age of infection. Bystander activation has little effect at younger ages and actually decreases incidence at later ages while accelerating disease in mice that do get the disease. A competitive immune response to infection can decrease incidence at young ages and increase it at older ages, with the effect decreasing over time. Finally, an induced Treg response decreases incidence at any age of infection, but the effect decreases with age. Some of these patterns resemble those seen experimentally. PMID:27030351

  17. Adsorption of coliphages T1 and T7 to clay minerals.

    PubMed Central

    Schiffenbauer, M; Stotzky, G

    1982-01-01

    Coliphages T1 and T7 of Escherichia coli were absorbed by kaolinite (K) and montmorillonite (M). Maximum adsorption of T7 (96%) to M was greater than that of T1 (84%), but the adsorption of both coliphages to K was the same (99%). Positively charged sites (i.e., anion exchange sites) on the clays appeared to be primarily responsible for the adsorption of T1 to K but only partially responsible for the adsorption of T1 to M; equilibrium adsorption isotherms of T1 to K and M did not show a correlation between adsorption and the cation exchange capacity of the clays, and the reduction in adsorption caused by sodium metaphosphate (a polyanion that interacts with positively charged sites on clay) was more pronounced with K than with M. The equilibrium adsorption isotherms of T7 to K and M suggested a correlation between adsorption and the cation exchange capacity of the clays. However, studies with sodium metaphosphate indicated that T7 also adsorbed to positively charged sites on the clays, especially on K. Adsorption of the coliphages to positively charged sites was greater with K than with M, probably because the ratio of positively charged sites to negatively charged sites was greater on K than on M. PMID:7041821

  18. Synthesis and biological evaluation of 3-(4-fluorophenyl)-1H-pyrazole derivatives as androgen receptor antagonists.

    PubMed

    Guo, Guangzhu; Liu, Jianzhen; Wang, Guanjie; Zhang, Daoguang; Lu, Jinjie; Zhao, Guisen

    2016-04-01

    A novel series of 3-(4-fluorophenyl)-1H-pyrazole derivatives were synthesized and evaluated for their antiproliferative activity against two prostate cancer cell lines (LNCaP and PC-3) and androgen receptor target gene prostate-specific antigen (PSA) inhibitory activity in LNCaP cells. Several compounds showed potent antiproliferative activity against LNCaP cells and showed a promising PSA downregulation rate. Among these, compound 10e selectively inhibited LNCaP cell growth with an IC50 value of 18 μmol/l and showed a PSA downregulation rate of 46%, which was better than the lead compound T3. PMID:26633887

  19. Hydrochemistry and 18O/16O and 2H/1H Ratios of Ugandan Waters

    NASA Astrophysics Data System (ADS)

    Gebremichael, M. G.; Jasechko, S.

    2013-12-01

    Today, 70% of the 35 million people living in Uganda have access to an improved water source, ranking Uganda 148 out of 179 nations reporting in 2010 (Millennium Development Goals Indicators). 80% of Ugandans rely on groundwater as their primary drinking water source, collecting at springs or from shallow wells. Similarly, 80% of Ugandans rely upon agriculture - usually rain fed - as their primary income source. Despite lack of access to protected water sources faced by 10 million Ugandans, and the importance of the blue economy to Uganda's continued development, a country-wide investigation of the chemistry and the stable oxygen and hydrogen isotope compositions of waters has yet to be completed. Here we present 250 analyses of 18O/16O, 2H/1H and dissolved ion concentrations of Ugandan lakes, rivers, groundwaters and springs collected during July, 2013. We use the new data to characterize regional scale groundwater recharge sources, advection pathways and interactions with surface waters. Large lakes - Albert, Edward and Victoria - show increases in 18O/16O and 2H/1H ratios consistent with open water evaporation, and are shown to be distinct from nearby groundwaters, suggesting minimal recharge from large lakes to the subsurface. Salinities of eastern Ugandan groundwaters are elevated relative to samples collected from the central and western regions, suggesting that longer groundwater residence times and enhanced water-rock interactions characterize these waters. Springs from western Uganda show a shift in 18O/16O to higher values as a result of hydrothermal water-rock exchanges. Dissolved ion and noble gas concentrations show potential for use in assessing geothermal energy resources, perhaps aiding the Ugandan Ministry for Energy, Minerals and Development to meet their goal of increasing renewable energy from 4% (current) to 61% of total use by 2017 (Nyakabwa-Atwoki, 2013). Millennium Development Goals Indicators. mdgs.un.org/unsd/mdg/data.aspx Nyakabwa

  20. 1H NMR studies of insulin: histidine residues, metal binding, and dissociation in alkaline solution.

    PubMed

    Ramesh, V; Bradbury, J H

    1987-10-01

    The shifts of the H2 histidine B5 and B10 resonances of 2-Zn insulin hexamer were followed in 2H2O by 1H NMR spectroscopy at 270 MHz from pH 9.85 to 7. The two resonances present at high pH, previously assigned to H2 histidine B5 and B10 residues, moved slightly downfield and split into four resonances at pH 8.95 and also at pH 7. By use of a paramagnetic broadening probe (Mn2+) and the addition of Zn2+ to metal-free insulin, it was deduced that the four resonances arose from histidines B10 and B5 in two different magnetic environments, probably either bound to Zn2+ or not bound to Zn2+. The pK' values of the B5 and B10 histidines were determined in 60% 2H2O-40% dioxan, in which insulin was soluble throughout the pH range, to be 7.1 and 6.8, respectively at 37 degrees C. Studies at higher pH indicated that at a concentration level suitable for 1H NMR (approximately 1 mM) at 37 degrees C in 2H2O the 2-Zn hexamer was largely dissociated to dimer at pH 10.3 and to monomer at pH 10.8. Addition of paramagnetic shift probe Ni2+ to metal-free insulin caused changes to the spectrum similar to those produced on addition of diamagnetic Zn2+. Addition of Co2+ gave a different result, but there was no paramagnetic shift of the H2 histidine B10 resonance, probably because of rapid exchange at the binding site. Addition of Cd2+ and of Cd2+ and Ca2+ produced changes that were similar to each other but were different from those observed on addition of Zn2+, probably due to the binding of Cd2+ and Ca2+ at glutamate B13. PMID:3310894

  1. /sup 1/H NMR studies of insulin: histidine residues, metal binding, and dissociation in alkaline solution

    SciTech Connect

    Ramesh, V.; Bradbury, J.H.

    1987-10-01

    The shifts of the H2 histidine B5 and B10 resonances of 2-Zn insulin hexamer were followed in /sup 2/H/sub 2/O by /sup 1/H NMR spectroscopy at 270 MHz from pH 9.85 to 7. The two resonances present at high pH, previously assigned to H2 histidine B5 and B10 residues, moved slightly downfield and split into four resonances at pH 8.95 and also at pH 7. By use of a paramagnetic broadening probe (Mn/sup 2 +/) and the addition of Zn/sup 2 +/ to metal-free insulin, it was deduced that the four resonances arose from histidines B10 and B5 in two different magnetic environments, probably either bound to Zn/sup 2 +/ or not bound to Zn/sup 2 +/. The pK' values of the B5 and B10 histidines were determined in 60% /sup 2/H/sub 2/O-40% dioxan, in which insulin was soluble throughout the pH range, to be 7.1 and 6.8, respectively at 37 degrees C. Studies at higher pH indicated that at a concentration level suitable for /sup 1/H NMR (approximately 1 mM) at 37 degrees C in /sup 2/H/sub 2/O the 2-Zn hexamer was largely dissociated to dimer at pH 10.3 and to monomer at pH 10.8. Addition of paramagnetic shift probe Ni/sup 2 +/ to metal-free insulin caused changes to the spectrum similar to those produced on addition of diamagnetic Zn/sup 2 +/. Addition of Co/sup 2 +/ gave a different result, but there was no paramagnetic shift of the H2 histidine B10 resonance, probably because of rapid exchange at the binding site. Addition of Cd/sup 2 +/ and of Cd/sup 2 +/ and Ca/sup 2 +/ produced changes that were similar to each other but were different from those observed on addition of Zn/sup 2 +/, probably due to the binding of Cd/sup 2 +/ and Ca/sup 2 +/ at glutamate B13.

  2. Initial evaluation of hepatic T1 relaxation time as an imaging marker of liver disease associated with autosomal recessive polycystic kidney disease (ARPKD).

    PubMed

    Gao, Ying; Erokwu, Bernadette O; DeSantis, David A; Croniger, Colleen M; Schur, Rebecca M; Lu, Lan; Mariappuram, Jose; Dell, Katherine M; Flask, Chris A

    2016-01-01

    Autosomal recessive polycystic kidney disease (ARPKD) is a potentially lethal multi-organ disease affecting both the kidneys and the liver. Unfortunately, there are currently no non-invasive methods to monitor liver disease progression in ARPKD patients, limiting the study of potential therapeutic interventions. Herein, we perform an initial investigation of T1 relaxation time as a potential imaging biomarker to quantitatively assess the two primary pathologic hallmarks of ARPKD liver disease: biliary dilatation and periportal fibrosis in the PCK rat model of ARPKD. T1 relaxation time results were obtained for five PCK rats at 3 months of age using a Look-Locker acquisition on a Bruker BioSpec 7.0 T MRI scanner. Six three-month-old Sprague-Dawley (SD) rats were also scanned as controls. All animals were euthanized after the three-month scans for histological and biochemical assessments of bile duct dilatation and hepatic fibrosis for comparison. PCK rats exhibited significantly increased liver T1 values (mean ± standard deviation = 935 ± 39 ms) compared with age-matched SD control rats (847 ± 26 ms, p = 0.01). One PCK rat exhibited severe cholangitis (mean T1  = 1413 ms), which occurs periodically in ARPKD patients. The observed increase in the in vivo liver T1 relaxation time correlated significantly with three histological and biochemical indicators of biliary dilatation and fibrosis: bile duct area percent (R = 0.85, p = 0.002), periportal fibrosis area percent (R = 0.82, p = 0.004), and hydroxyproline content (R = 0.76, p = 0.01). These results suggest that hepatic T1 relaxation time may provide a sensitive and non-invasive imaging biomarker to monitor ARPKD liver disease. PMID:26608869

  3. The clinical significance of a second transurethral resection for T1 high-grade bladder cancer: Results of a prospective study

    PubMed Central

    Shim, Ji Sung; Choi, Hoon; Noh, Tae Il; Tae, Jong Hyun; Yoon, Sung Goo; Kang, Seok Ho; Bae, Jae Hyun; Park, Hong Seok

    2015-01-01

    Purpose This study was designed to estimate the value of a second transurethral resection of bladder tumor (TURBT) procedure in patients with initially diagnosed T1 high-grade bladder cancer. Materials and Methods Between August 2009 and January 2013, a total of 29 patients with T1 high-grade bladder cancer prospectively underwent a second TURBT procedure. Evaluation included the presence of previously undetected residual tumor, changes to histopathological staging or grading, and tumor location. Recurrence-free and progression-free survival curves were generated to compare the prognosis between the groups with and without residual lesions by use of the Kaplan-Meier method. Results Of 29 patients, 22 patients (75.9%) had residual disease after the second TURBT. Staging was as follows: no tumor, 7 (24.1%); Ta, 5 (17.2%); T1, 6 (20.7%); Tis, 6 (20.7%); Ta+Tis, 1 (3.4%); T1+Tis, 1 (3.4%); and ≥T2, 3 (10.3%). The muscle layer was included in the surgical specimen after the initial TURBT in 24 patients (82.7%). In three patients whose cancer was upstaged to pT2 after the second TURBT, the initial surgical specimen contained the muscle layer. In the group with residual lesions, the 3-year recurrence-free survival and 3-year progression-free survival rates were 50% and 66.9%, respectively, whereas these rates were 68.6% and 68.6%, respectively, in the group without residual lesions. This difference was not statistically significant. Conclusions Initial TURBT does not seem to be enough to control T1 high-grade bladder cancer. Therefore, a routine second TURBT procedure should be recommended in patients with T1 high-grade bladder cancer to accomplish adequate tumor resection and to identify patients who may need to undergo prompt cystectomy. PMID:26078839

  4. Assessment of myocardial changes in athletes with native T1 mapping and cardiac functional evaluation using 3 T MRI.

    PubMed

    Görmeli, Cemile Ayşe; Görmeli, Gökay; Yağmur, Jülide; Özdemir, Zeynep Maraş; Kahraman, Ayşegül Sağır; Çolak, Cemil; Özdemir, Ramazan

    2016-06-01

    Intensive physical exercise leads to increases in left ventricular muscle mass and wall thickness. Cardiac magnetic resonance imaging allows the assessment of functional and morphological changes in an athlete's heart. In addition, a native T1 mapping technique has been suggested as a non-contrast method to detect myocardial fibrosis. The aim of this study was to show the correlation between athletes' cardiac modifications and myocardial fibrosis with a native T1 mapping technique. A total of 41 healthy non-athletic control subjects and 46 athletes underwent CMR imaging. After the functional and morphological assessments, native T1 mapping was performed in all subjects using 3.0 T magnetic resonance imaging. Most of the CMR findings were significantly higher in athletes who had ≥5 years of sports activity when compared with non-athletic controls and athletes who had <5 years of sports activity. Significantly higher results were shown in native T1 values in athletes who had <5 years of sports activity, but there were no significant differences in the left ventricular end-diastolic volume, left ventricular end-diastolic mass, or interventricular septal wall thickness between non-athletic controls and athletes who had <5 years of sports activity. The native T1 mapping technique has the potential to discriminate myocardial fibrotic changes in athletes when compared to a normal myocardium. The T1 mapping method might be a feasible technique to evaluate athletes because it does not involve contrast, is non-invasive and allows for easy evaluation of myocardial remodeling. PMID:26920720

  5. Galápagos hydroclimate of the Common Era from paired microalgal and mangrove biomarker 2H/1H values

    NASA Astrophysics Data System (ADS)

    Nelson, Daniel B.; Sachs, Julian P.

    2016-03-01

    Tropical maritime precipitation affects global atmospheric circulation, influencing storm tracks and the size and location of subtropical deserts. Paleoclimate evidence suggests centuries-long changes in rainfall in the tropical Pacific over the past 2,000 y, but these remain poorly characterized across most of the ocean where long, continuous proxy records capable of resolving decadal-to-centennial climate changes are still virtually nonexistent despite substantial efforts to develop them. Here we apply a new climate proxy based on paired hydrogen isotope ratios from microalgal and mangrove-derived sedimentary lipids in the Galápagos to reconstruct maritime precipitation changes during the Common Era. We show that increased rainfall during the Little Ice Age (LIA) (∼1400-1850 CE) was likely caused by a southward migration of the Intertropical Convergence Zone (ITCZ), and that this shift occurred later than previously recognized, coeval with dynamically linked precipitation changes in South America and the western tropical Pacific. Before the LIA, we show that drier conditions at the onset of the Medieval Warm Period (∼800-1300 CE) and wetter conditions ca. 2 ka were caused by changes in the El Niño/Southern Oscillation (ENSO). Collectively, the large natural variations in tropical rainfall we detect, each linked to a multicentury perturbation of either ENSO-like variability or the ITCZ, imply a high sensitivity of tropical Pacific rainfall to climate forcings.

  6. Galápagos hydroclimate of the Common Era from paired microalgal and mangrove biomarker 2H/1H values.

    PubMed

    Nelson, Daniel B; Sachs, Julian P

    2016-03-29

    Tropical maritime precipitation affects global atmospheric circulation, influencing storm tracks and the size and location of subtropical deserts. Paleoclimate evidence suggests centuries-long changes in rainfall in the tropical Pacific over the past 2,000 y, but these remain poorly characterized across most of the ocean where long, continuous proxy records capable of resolving decadal-to-centennial climate changes are still virtually nonexistent despite substantial efforts to develop them. Here we apply a new climate proxy based on paired hydrogen isotope ratios from microalgal and mangrove-derived sedimentary lipids in the Galápagos to reconstruct maritime precipitation changes during the Common Era. We show that increased rainfall during the Little Ice Age (LIA) (∼1400-1850 CE) was likely caused by a southward migration of the Intertropical Convergence Zone (ITCZ), and that this shift occurred later than previously recognized, coeval with dynamically linked precipitation changes in South America and the western tropical Pacific. Before the LIA, we show that drier conditions at the onset of the Medieval Warm Period (∼800-1300 CE) and wetter conditions ca. 2 ka were caused by changes in the El Niño/Southern Oscillation (ENSO). Collectively, the large natural variations in tropical rainfall we detect, each linked to a multicentury perturbation of either ENSO-like variability or the ITCZ, imply a high sensitivity of tropical Pacific rainfall to climate forcings. PMID:26976574

  7. 2D 1H and 3D 1H-15N NMR of zinc-rubredoxins: contributions of the beta-sheet to thermostability.

    PubMed Central

    Richie, K. A.; Teng, Q.; Elkin, C. J.; Kurtz, D. M.

    1996-01-01

    Based on 2D 1H-1H and 2D and 3D 1H-15N NMR spectroscopies, complete 1H NMR assignments are reported for zinc-containing Clostridium pasteurianum rubredoxin (Cp ZnRd). Complete 1H NMR assignments are also reported for a mutated Cp ZnRd, in which residues near the N-terminus, namely, Met 1, Lys 2, and Pro 15, have been changed to their counterparts, (-), Ala and Glu, respectively, in rubredoxin from the hyperthermophilic archaeon, Pyrococcus furiosus (Pf Rd). The secondary structure of both wild-type and mutated Cp ZnRds, as determined by NMR methods, is essentially the same. However, the NMR data indicate an extension of the three-stranded beta-sheet in the mutated Cp ZnRd to include the N-terminal Ala residue and Glu 15, as occurs in Pf Rd. The mutated Cp Rd also shows more intense NOE cross peaks, indicating stronger interactions between the strands of the beta-sheet and, in fact, throughout the mutated Rd. However, these stronger interactions do not lead to any significant increase in thermostability, and both the mutated and wild-type Cp Rds are much less thermostable than Pf Rd. These correlations strongly suggest that, contrary to a previous proposal [Blake PR et al., 1992, Protein Sci 1:1508-1521], the thermostabilization mechanism of Pf Rd is not dominated by a unique set of hydrogen bonds or electrostatic interactions involving the N-terminal strand of the beta-sheet. The NMR results also suggest that an overall tighter protein structure does not necessarily lead to increased thermostability. PMID:8732760

  8. T1-weighted MRI as a substitute to CT for refocusing planning in MR-guided focused ultrasound

    NASA Astrophysics Data System (ADS)

    Wintermark, Max; Tustison, Nicholas J.; Elias, William J.; Patrie, James T.; Xin, Wenjun; Demartini, Nicholas; Eames, Matt; Sumer, Suna; Lau, Benison; Cupino, Alan; Snell, John; Hananel, Arik; Kassell, Neal; Aubry, Jean-Francois

    2014-07-01

    Precise focusing is essential for transcranial MRI-guided focused ultrasound (TcMRgFUS) to minimize collateral damage to non-diseased tissues and to achieve temperatures capable of inducing coagulative necrosis at acceptable power deposition levels. CT is usually used for this refocusing but requires a separate study (CT) ahead of the TcMRgFUS procedure. The goal of this study was to determine whether MRI using an appropriate sequence would be a viable alternative to CT for planning ultrasound refocusing in TcMRgFUS. We tested three MRI pulse sequences (3D T1 weighted 3D volume interpolated breath hold examination (VIBE), proton density weighted 3D sampling perfection with applications optimized contrasts using different flip angle evolution and 3D true fast imaging with steady state precision T2-weighted imaging) on patients who have already had a CT scan performed. We made detailed measurements of the calvarial structure based on the MRI data and compared those so-called ‘virtual CT’ to detailed measurements of the calvarial structure based on the CT data, used as a reference standard. We then loaded both standard and virtual CT in a TcMRgFUS device and compared the calculated phase correction values, as well as the temperature elevation in a phantom. A series of Bland-Altman measurement agreement analyses showed T1 3D VIBE as the optimal MRI sequence, with respect to minimizing the measurement discrepancy between the MRI derived total skull thickness measurement and the CT derived total skull thickness measurement (mean measurement discrepancy: 0.025; 95% CL (-0.22-0.27) p = 0.825). The T1-weighted sequence was also optimal in estimating skull CT density and skull layer thickness. The mean difference between the phase shifts calculated with the standard CT and the virtual CT reconstructed from the T1 dataset was 0.08 ± 1.2 rad on patients and 0.1 ± 0.9 rad on phantom. Compared to the real CT, the MR-based correction showed a 1 °C drop on the maximum

  9. Improved model of the Earth's gravitational field: GEM-T1

    SciTech Connect

    Marsh, J.G.; Lerch, F.J.; Christodoulidis, D.C.; Putney, B.H.; Felsentreger, T.L.; Sanchez, B.V.; Smith, D.E.; Klosko, S.M.; Martin, T.V.; Pavlis, E.C.

    1987-07-01

    Goddard Earth Model T1 (GEM-T1), which was developed from an analysis of direct satellite tracking observations, is the first in a new series of such models. GEM-T1 is complete to degree and order 36. It was developed using consistent reference parameters and extensive earth and ocean tidal models. It was simultaneously solved for gravitational and tidal terms, earth orientation parameters, and the orbital parameters of 580 individual satellite arcs. The solution used only satellite tracking data acquired on 17 different satellites and is predominantly based upon the precise laser data taken by third generation systems. In all, 800,000 observations were used. A major improvement in field accuracy was obtained. For marine geodetic applications, long wavelength geoidal modeling is twice as good as in earlier satellite-only GEM models. Orbit determination accuracy has also been substantially advanced over a wide range of satellites that have been tested.

  10. Some Psychological Aspects of T1DM in Children and Adolescents.

    PubMed

    Pop-Jordanova, Nada; Gucev, Zoran

    2015-01-01

    Diabetes mellitus type 1 (T1DM) is a chronic disease with long term consequences dictating daily struggle to maintain a good metabolic control. Children and adolescents with T1DM seem to have inferior psychological adjustment to their normal counterparts, which might be associated with glycemic control and disease duration. The aim of this study is to evaluate the psychological characteristics of children and adolescents with T1DM treated last year in the University Children Hospital in Skopje, Macedonia and to propose some response measures. For psychological evaluation we used CBCL (Child Behavior Check List), GAS (General Anxiety Scale), EPQ (Eysenck Personality Questionnaire) and MMPI-201 (Minnesota Multiphasic Personality Inventory). The results confirmed the following psychological characteristics: mild depression and anxiety, emotional instability, need for social acceptance, as well as the possible psychopathic traits. Suffering for a complex metabolic and chronic illness, these patients need psychological evaluation and intervention in the management. PMID:27442404

  11. Bacteriophage CP-T1 of Vibrio cholerae. Identification of the cell surface receptor.

    PubMed

    Guidolin, A; Manning, P A

    1985-11-15

    The attachment site on the cell surface of Vibrio cholerae for the bacteriophage CP-T1 has been determined. Purified lipopolysaccharide from the Inaba and Ogawa serotypes, and of both the Classical and El Tor biotype of strains of V. cholerae show equal phage-inactivating capacities. Lipopolysaccharide extracted from a CP-T1-resistant mutant has no phage-inactivating capacity. Such mutants lack O-antigen as demonstrated by bactericidal assays utilizing a monoclonal antibody directed against O-antigen side chain of V. cholerae lipopolysaccharide. Radiolabelling of lipopolysaccharide with 33P and analysis by sodium dodecyl sulfate/polyacrylamide gel electrophoresis also revealed the absence of O-antigen in phage-resistant strains. A number of V. cholerae typing phage show cross-resistance with phage CP-T1. PMID:4065151

  12. An improved model of the Earth's gravitational field: GEM-T1

    NASA Technical Reports Server (NTRS)

    Marsh, J. G.; Lerch, F. J.; Christodoulidis, D. C.; Putney, B. H.; Felsentreger, T. L.; Sanchez, B. V.; Smith, D. E.; Klosko, S. M.; Martin, T. V.; Pavlis, E. C.

    1987-01-01

    Goddard Earth Model T1 (GEM-T1), which was developed from an analysis of direct satellite tracking observations, is the first in a new series of such models. GEM-T1 is complete to degree and order 36. It was developed using consistent reference parameters and extensive earth and ocean tidal models. It was simultaneously solved for gravitational and tidal terms, earth orientation parameters, and the orbital parameters of 580 individual satellite arcs. The solution used only satellite tracking data acquired on 17 different satellites and is predominantly based upon the precise laser data taken by third generation systems. In all, 800,000 observations were used. A major improvement in field accuracy was obtained. For marine geodetic applications, long wavelength geoidal modeling is twice as good as in earlier satellite-only GEM models. Orbit determination accuracy has also been substantially advanced over a wide range of satellites that have been tested.

  13. Hybrid Nanotrimers for Dual T1 and T2-Weighted Magnetic Resonance Imaging

    PubMed Central

    2015-01-01

    Development of multifunctional nanoparticle-based probes for dual T1- and T2-weighted magnetic resonance imaging (MRI) could allow us to image and diagnose the tumors or other abnormalities in an exceptionally accurate and reliable manner. In this study, by fusing distinct nanocrystals via solid-state interfaces, we built hybrid heteronanostructures to combine both T1 and T2- weighted contrast agents together for MRI with high accuracy and reliability. The resultant hybrid heterotrimers showed high stability in physiological conditions and could induce both simultaneous positive and negative contrast enhancements in MR images. Small animal positron emission tomography imaging study revealed that the hybrid heterostructures displayed favorable biodistribution and were suitable for in vivo imaging. Their potential as dual contrast agents for T1 and T2-weighted MRI was further demonstrated by in vitro and in vivo imaging and relaxivity measurements. PMID:25283972

  14. A novel method for isolation and concentration of ribonuclease T1 from Taka-Diastase.

    PubMed

    Zhang, Q J; Liu, Z Y

    1990-01-01

    A novel method for isolation and concentration of RNase T1 from Taka-Diastase is developed. It is a combination method of bentonite adsorption with dialysis desorption. In the present method, RNase T1 can be concentrated about ten-fold, the recovery of total activity was greater than 95%, and specific activity was raised 8-10 folds. Further purification with ammonium sulfate precipitation and chromatography on DEAE-cellulose and DEAE-Sephadex yields a RNase T1 which contains no pMase. pDase nor RNase T2 activities and a 750 fold increase in specific activity. Our method is more simple, rapid, and efficient than previous methods. PMID:2126867

  15. Lumazine Synthase Protein Nanoparticle-Gd(III)-DOTA Conjugate as a T1 contrast agent for high-field MRI

    PubMed Central

    Song, YoungKyu; Kang, Young Ji; Jung, Hoesu; Kim, Hansol; Kang, Sebyung; Cho, HyungJoon

    2015-01-01

    With the applications of magnetic resonance imaging (MRI) at higher magnetic fields increasing, there is demand for MRI contrast agents with improved relaxivity at higher magnetic fields. Macromolecule-based contrast agents, such as protein-based ones, are known to yield significantly higher r1 relaxivity at low fields, but tend to lose this merit when used as T1 contrast agents (r1/r2 = 0.5 ~ 1), with their r1 decreasing and r2 increasing as magnetic field strength increases. Here, we developed and characterized an in vivo applicable magnetic resonance (MR) positive contrast agent by conjugating Gd(III)-chelating agent complexes to lumazine synthase isolated from Aquifex aeolicus (AaLS). The r1 relaxivity of Gd(III)-DOTA-AaLS-R108C was 16.49 mM−1s−1 and its r1/r2 ratio was 0.52 at the magnetic field strength of 7 T. The results of 3D MR angiography demonstrated the feasibility of vasculature imaging within 2 h of intravenous injection of the agent and a significant reduction in T1 values were observed in the tumor region 7 h post-injection in the SCC-7 flank tumor model. Our findings suggest that Gd(III)-DOTA-AaLS-R108C could serve as a potential theranostic nanoplatform at high magnetic field strength. PMID:26493381

  16. Lumazine Synthase Protein Nanoparticle-Gd(III)-DOTA Conjugate as a T1 contrast agent for high-field MRI.

    PubMed

    Song, YoungKyu; Kang, Young Ji; Jung, Hoesu; Kim, Hansol; Kang, Sebyung; Cho, HyungJoon

    2015-01-01

    With the applications of magnetic resonance imaging (MRI) at higher magnetic fields increasing, there is demand for MRI contrast agents with improved relaxivity at higher magnetic fields. Macromolecule-based contrast agents, such as protein-based ones, are known to yield significantly higher r1 relaxivity at low fields, but tend to lose this merit when used as T1 contrast agents (r1/r2 = 0.5 ~ 1), with their r1 decreasing and r2 increasing as magnetic field strength increases. Here, we developed and characterized an in vivo applicable magnetic resonance (MR) positive contrast agent by conjugating Gd(III)-chelating agent complexes to lumazine synthase isolated from Aquifex aeolicus (AaLS). The r1 relaxivity of Gd(III)-DOTA-AaLS-R108C was 16.49 mM(-1)s(-1) and its r1/r2 ratio was 0.52 at the magnetic field strength of 7 T. The results of 3D MR angiography demonstrated the feasibility of vasculature imaging within 2 h of intravenous injection of the agent and a significant reduction in T1 values were observed in the tumor region 7 h post-injection in the SCC-7 flank tumor model. Our findings suggest that Gd(III)-DOTA-AaLS-R108C could serve as a potential theranostic nanoplatform at high magnetic field strength. PMID:26493381

  17. Glasses of the As/sub 2/S/sub 3/-T1/sub 2/S system

    SciTech Connect

    Gutenev, M.S.

    1986-08-01

    A dielcometric study of (AsS /SUB 1.5/ ) /SUB 1-x/ (TiS /SUB 0.5/ ) /SUB x/ (0 is less than or equal to x is less than or equal to 0.61) glasses was carried out. Glassforming alloys were prepared in thin-walled quartz ampules by rapid cooling from 700 C in air. The methods of determination of permittivity, refractive index, and density, the values of which are shown here, have been previously discussed. The molar infrared polarizability is calculated from the experimental data previously gathered, and the concentration dependence is shown. In this paper, the presence of chemical atomic order in T1AsS/sub 2/ glass described by TISAsS /SUB 2/2/ structural units was experimentally proved. An assumption was made of strong mutual influence of T1AsS/sub 2/ and AsS /SUB 1.5/ complexes caused by coordination of thallium with bridging sulfur atoms.

  18. Radical cystectomy for the treatment of T1 bladder cancer: the Canadian Bladder Cancer Network experience

    PubMed Central

    Chalasani, Venu; Kassouf, Wassim; Chin, Joseph L.; Fradet, Yves; Aprikian, Armen G.; Fairey, Adrian S.; Estey, Eric; Lacombe, Louis; Rendon, Ricardo; Bell, David; Cagiannos, Ilias; Drachenberg, Darrell; Lattouf, Jean-Baptiste; Izawa, Jonathan I.

    2011-01-01

    Background: Radical cystectomy may provide optimal survival outcomes in the management of clinical T1 bladder cancer. We present our data from a large, multi-institutional, contemporary Canadian series of patients who underwent radical cystectomy for clinical T1 bladder cancer in a single-payer health care system. Methods: We collected a pooled database of 2287 patients who underwent radical cystectomy between 1993 and 2008 in 8 different centres across Canada; 306 of these patients had clinical T1 bladder cancer. Survival data were analyzed using Kaplan-Meier method and Cox regression analysis. Results: The median age of patients was 67 years with a mean follow-up time of 35 months. The 5-year overall, disease-specific and disease-free survival was 71%, 77% and 59%, respectively. The 10-year overall and disease-specific survival were 60% and 67%, respectively. Pathologic stage distribution was p0: 32 (11%), pT1: 78 (26%), pT2: 55 (19%), pT3: 60 (20%), pT4: 27 (9%), pTa: 16 (5%), pTis: 28 (10%), pN0: 215 (74%) and pN1-3: 78 (26%). Only 12% of patients were given adjuvant chemotherapy. On multivariate analysis, only margin status and pN stage were independently associated with overall, disease-specific and disease-free survival. Interpretation: These results indicate that clinical T1 bladder cancer may be significantly understaged. Identifying factors associated with understaged and/or disease destined to progress (despite any prior intravesical or repeat transurethral therapies prior to radical cystectomy) will be critical to improve survival outcomes without over-treating clinical T1 disease that can be successfully managed with bladder preservation strategies. PMID:21470529

  19. Modeling T1 and T2 relaxation in bovine white matter

    NASA Astrophysics Data System (ADS)

    Barta, R.; Kalantari, S.; Laule, C.; Vavasour, I. M.; MacKay, A. L.; Michal, C. A.

    2015-10-01

    The fundamental basis of T1 and T2 contrast in brain MRI is not well understood; recent literature contains conflicting views on the nature of relaxation in white matter (WM). We investigated the effects of inversion pulse bandwidth on measurements of T1 and T2 in WM. Hybrid inversion-recovery/Carr-Purcell-Meiboom-Gill experiments with broad or narrow bandwidth inversion pulses were applied to bovine WM in vitro. Data were analysed with the commonly used 1D-non-negative least squares (NNLS) algorithm, a 2D-NNLS algorithm, and a four-pool model which was based upon microscopically distinguishable WM compartments (myelin non-aqueous protons, myelin water, non-myelin non-aqueous protons and intra/extracellular water) and incorporated magnetization exchange between adjacent compartments. 1D-NNLS showed that different T2 components had different T1 behaviours and yielded dissimilar results for the two inversion conditions. 2D-NNLS revealed significantly more complicated T1/T2 distributions for narrow bandwidth than for broad bandwidth inversion pulses. The four-pool model fits allow physical interpretation of the parameters, fit better than the NNLS techniques, and fits results from both inversion conditions using the same parameters. The results demonstrate that exchange cannot be neglected when analysing experimental inversion recovery data from WM, in part because it can introduce exponential components having negative amplitude coefficients that cannot be correctly modeled with nonnegative fitting techniques. While assignment of an individual T1 to one particular pool is not possible, the results suggest that under carefully controlled experimental conditions the amplitude of an apparent short T1 component might be used to quantify myelin water.

  20. Phase Diagram of Bilayer 2D Electron Systems at νT = 1

    NASA Astrophysics Data System (ADS)

    Champagne, Alexandre

    2009-03-01

    Bilayer 2D electron systems at total filling fraction νT = 1 and small interlayer spacing can support a strongly correlated phase which exhibits spontaneous interlayer phase coherence and may be described as an excitonic Bose condensate. We use electron interlayer tunnelling and transport to explore the phase diagram of bilayer 2D electron systems at νT = 1, and find that phase transitions between the excitonic νT = 1 phase and bilayer states which lack significant interlayer correlations can be induced in three different ways: by increasing the effective interlayer spacing, d/l, the temperature, T, or the charge imbalance, δν=ν1-ν2. First, for the balanced (δν = 0) system we find that the amplitude of the resonant tunneling in the coherent νT = 1 phase obeys an empirical power law scaling versus d/l at various T, and the layer separation where the tunneling disappears scales linearly with T. Our results [1] offer strong evidence that a finite temperature phase transition separates the balanced interlayer coherent phase from incoherent phases which lack strong interlayer correlations. Secondly, we observe [2] that close to the phase boundary the coherent νT = 1 phase can be absent at δν = 0, present at intermediate δν, and absent again at large δν, thus indicating an intricate phase competition between it and incoherent quasi-independent layer states. Lastly, at δν = 1/3 we report [2] the observation of a direct phase transition between the coherent νT = 1 bilayer integer quantum Hall phase and the pair of single layer fractional quantized Hall states at ν1 = 2/3 and ν2 = 1/3.[4pt] [1] A.R. Champagne, et al., Phys. Rev. Lett. 100, 096801 (2008).[0pt] [2] A.R. Champagne, et al, Phys. Rev. B 78, 205310 (2008)

  1. Intermolecular Interactions between Eosin Y and Caffeine Using (1)H-NMR Spectroscopy.

    PubMed

    Okuom, Macduff O; Wilson, Mark V; Jackson, Abby; Holmes, Andrea E

    2013-12-31

    DETECHIP has been used in testing analytes including caffeine, cocaine, and tetrahydrocannabinol (THC) from marijuana, as well as date rape and club drugs such as flunitrazepam, gamma-hydroxybutyric acid (GHB), and methamphetamine. This study investigates the intermolecular interaction between DETECHIP sensor eosin Y (DC1) and the analyte (caffeine) that is responsible for the fluorescence and color changes observed in the actual array. Using (1)H-NMR, (1)H-COSY, and (1)H-DOSY NMR methods, a proton exchange from C-8 of caffeine to eosin Y is proposed. PMID:25018772

  2. Intermolecular Interactions between Eosin Y and Caffeine Using 1H-NMR Spectroscopy

    PubMed Central

    Okuom, Macduff O.; Wilson, Mark V.; Jackson, Abby; Holmes, Andrea E.

    2014-01-01

    DETECHIP has been used in testing analytes including caffeine, cocaine, and tetrahydrocannabinol (THC) from marijuana, as well as date rape and club drugs such as flunitrazepam, gamma-hydroxybutyric acid (GHB), and methamphetamine. This study investigates the intermolecular interaction between DETECHIP sensor eosin Y (DC1) and the analyte (caffeine) that is responsible for the fluorescence and color changes observed in the actual array. Using 1H-NMR, 1H-COSY, and 1H-DOSY NMR methods, a proton exchange from C-8 of caffeine to eosin Y is proposed. PMID:25018772

  3. 1H to 13C Energy Transfer in Solid State NMR Spectroscopy of Natural Organic Systems

    NASA Astrophysics Data System (ADS)

    Berns, Anne E.; Conte, Pellegrino

    2010-05-01

    Cross polarization (CP) magic angle spinning (MAS) 13C-NMR spectroscopy is a solid state NMR technique widely used to study chemical composition of organic materials with low or no solubility in the common deuterated solvents used to run liquid state NMR experiments. Based on the magnetization transfer from abundant nuclei (with spin of 1 -2) having a high gyromagnetic ratio (γ), such as protons, to the less abundant 13C nuclei with low γ values, 13C-CPMAS NMR spectroscopy is often applied in environmental chemistry to obtain quantitative information on the chemical composition of natural organic matter (NOM) (Conte et al., 2004), although its quantitative assessment is still matter of heavy debates. Many authors (Baldock et al., 1997; Conte et al., 1997, 2002; Dria et al., 2002; Kiem et al., 2000; Kögel-Knabner, 2000; Preston, 2001), reported that the application of appropriate instrument setup as well as the use of special pulse sequences and correct spectra elaboration may provide signal intensities that are directly proportional to the amount of nuclei creating a NMR signal. However, many other papers dealt with the quantitative unsuitability of 13C-CPMAS NMR spectroscopy. Among those, Mao et al. (2000), Smernik and Oades (2000 a,b), and Preston (2001) reported that cross-polarized NMR techniques may fail in a complete excitation of the 13C nuclei. In fact, the amount of observable carbons via 13C-CPMAS NMR spectroscopy appeared, in many cases, lower than that measured by a direct observation of the 13C nuclei. As a consequence, cross-polarized NMR techniques may provide spectra where signal distribution may not be representative of the quantitative distribution of the different natural organic matter components. Cross-polarization is obtained after application of an initial 90° x pulse on protons and a further spin lock pulse (along the y axis) having a fixed length (contact time) for both nuclei (1H and 13C) once the Hartmann-Hahn condition is matched

  4. An improved error assessment for the GEM-T1 gravitational model

    NASA Technical Reports Server (NTRS)

    Lerch, F. J.; Marsh, J. G.; Klosko, S. M.; Pavlis, E. C.; Patel, G. B.; Chinn, D. S.; Wagner, C. A.

    1989-01-01

    Several tests were designed to determine the correct error variances for the GEM-T1 gravitational solution which was derived exclusively from satellite tracking data. The basic method employs both wholly independent and dependent subset data solutions and produces a full field coefficient by coefficient estimate of the model uncertainties. The GEM-T1 errors were further analyzed using a method based upon eigenvalue-eigenvector analysis which calibrates the entire covariance matrix. Dependent satellite and independent altimetric and surface gravity data sets, as well as independent satellite deep resonance information, confirm essentially the same error assessment.

  5. Measurement of edge plasma parameters in IR-T1 Tokamak by double Langmuir probe

    SciTech Connect

    Ghoranneviss, M.; Khademian, A.; Masnavi, M.; Khorshid, P.; Salami, M.R.

    1996-12-31

    IR-T1 Tokamak is an air-core transformer type Tokamak. The vacuum chamber was made of 4 mm thick stainless steel with minor and major radii of 12.5 cm and 45 cm as respectively. Measurements of T{sub e} have been observed in IR-T1 with fabricated circuits of double pore design. This pore can be movable in the horizontal direction, therefore one can measure temperature along 1 cm distance. This note presents a theoretical and experimental explanation of double probe techniques. Details will be discussed in the full paper.

  6. Ploidy status and the response of T1 glottic carcinoma to radiotherapy.

    PubMed

    Westerbeek, H A; Mooi, W J; Hilgers, F J; Baris, G; Begg, A C; Balm, A J

    1993-04-01

    Flow cytometric DNA ploidy measurements were performed on formalin fixed paraffin embedded tumour specimens from patients with a T1 glottic laryngeal carcinoma in order to evaluate the role of DNA content in relation to local control. From 1980 to 1987, a consecutive series of 90 patients with a T1 glottic laryngeal carcinoma were treated by radiotherapy with curative intent. Biopsies from 44 of these patients were readily available for DNA flow cytometry. In this group aneuploidy was associated with a significantly higher risk (P = 0.018) of local recurrence within 2 years after completion of radiotherapy (38% vs. 9% in the diploid group). PMID:8508549

  7. What Value "Value Added"?

    ERIC Educational Resources Information Center

    Richards, Andrew

    2015-01-01

    Two quantitative measures of school performance are currently used, the average points score (APS) at Key Stage 2 and value-added (VA), which measures the rate of academic improvement between Key Stage 1 and 2. These figures are used by parents and the Office for Standards in Education to make judgements and comparisons. However, simple…

  8. High-resolution magic angle spinning and 1H magnetic resonance spectroscopy reveal significantly altered neuronal metabolite profiles in CLN1 but not in CLN3.

    PubMed

    Sitter, Beathe; Autti, Taina; Tyynelä, Jaana; Sonnewald, Ursula; Bathen, Tone F; Puranen, Johanna; Santavuori, Pirkko; Haltia, Matti J; Paetau, Anders; Polvikoski, Tuomo; Gribbestad, Ingrid S; Häkkinen, Anna-Maija

    2004-09-01

    The neuronal ceroid lipofuscinoses (NCLs) are among the most severe inherited progressive neurodegenerative disorders of children. The purpose of this study was to compare the in vivo 1.5-T 1H magnetic resonance (MR) and ex vivo 14.3-T high-resolution (HR) magic angle spinning (MAS) 1H MR brain spectra of patients with infantile (CLN1) and juvenile (CLN3) types of NCL, to obtain detailed information about the alterations in the neuronal metabolite profiles in these diseases and to test the suitability of the ex vivo HR MAS (1)H MRS technique in analysis of autopsy brain tissue. Ex vivo spectra from CLN1 autopsy brain tissue (n = 9) significantly differed from those of the control (n = 9) and CLN3 (n = 5) groups, although no differences were found between the CLN3 and the control groups. Principal component analysis of ex vivo data showed that decreased levels of N-acetylaspartate (NAA), gamma-aminobutyric acid (GABA), glutamine, and glutamate as well as increased levels of inositols characterized the CLN1 spectra. Also, the intensity ratio of lipid methylene/methyl protons was decreased in spectra of CLN1 brain tissue compared with CLN3 and control brain tissue. In concordance with the ex vivo data, the in vivo spectra of late-stage patients with CLN1 (n = 3) revealed a dramatic decrease of NAA and a proportional increase of myo-inositol and lipids compared with control subjects. Again, the spectra of patients with CLN3 (n = 13) did not differ from those of controls (n = 15). In conclusion, the ex vivo and in vivo spectroscopic findings were in good agreement within all analyzed groups and revealed significant alterations in metabolite profiles in CLN1 brain tissue but not in CLN3 compared with controls. Furthermore, HR MAS 1H MR spectra facilitated refined detection of neuronal metabolites, including GABA, and composition of lipids in the autopsy brain tissue of NCL patients. PMID:15352223

  9. Responsive Copolymer Brushes of Poly[(2-(Methacryloyloxy)Ethyl) Trimethylammonium Chloride] (PMETAC) and Poly((1) H,(1) H,(2) H,(2) H-Perfluorodecyl acrylate) (PPFDA) to Modulate Surface Wetting Properties.

    PubMed

    Politakos, Nikolaos; Azinas, Stavros; Moya, Sergio Enrique

    2016-04-01

    Polymer brushes have a large potential for controlling properties such as surface lubrication or wetting through facile functionalization. Polymer chemistry, chain density, and length impact on the wetting properties of brushes. This study explores the use of diblock copolymer brushes with different block length and spatial arrangement of the blocks to tune surface wettability. Block copolymer brushes of the polyelectrolyte [2-(methacryloyloxy)ethyl] trimethylammonium chloride (PMETAC) with a contact angle of 17° and a hydrophobic block of (1) H, (1) H, (2) H, (2) H-perfluorodecyl Acrylate (PPFDA) with a contact angle of 130° are synthesized by RAFT polymerization. By changing the sequence of polymerization either block is synthesized as top or bottom block. By varying the concentration of initiator the length of the blocks is varied. Contact angle values with intermediate values between 17° and 130° are measured. In addition, by changing solvent pH and in presence of a different salt the contact angle of the copolymer brushes can be fine tuned. Brushes are characterized by atomic force microscopy, Raman confocal microscopy, and X-ray photoelectron spectroscopy. PMID:26872001

  10. Protection against T1DM-Induced Bone Loss by Zinc Supplementation: Biomechanical, Histomorphometric, and Molecular Analyses in STZ-Induced Diabetic Rats

    PubMed Central

    Bortolin, Raul Hernandes; da Graça Azevedo Abreu, Bento João; Abbott Galvão Ururahy, Marcela; Costa de Souza, Karla Simone; Bezerra, João Felipe; Bezerra Loureiro, Melina; da Silva, Flávio Santos; Marques, Dáfiny Emanuele da Silva; Batista, Angélica Amanda de Sousa; Oliveira, Gisele; Luchessi, André Ducati; Lima, Valéria Morgiana Gualberto Duarte Moreira; Miranda, Carlos Eduardo Saraiva; Lia Fook, Marcus Vinicius; Almeida, Maria das Graças; de Rezende, Luciana Augusto; de Rezende, Adriana Augusto

    2015-01-01

    Several studies have established an association between diabetes and alterations in bone metabolism; however, the underlying mechanism is not well established. Although zinc is recognized as a potential preventive agent against diabetes-induced bone loss, there is no evidence demonstrating its effect in chronic diabetic conditions. This study evaluated the effects of zinc supplementation in a chronic (90 days) type 1 diabetes-induced bone-loss model. Male Wistar rats were distributed in three groups: control, type 1 diabetes mellitus (T1DM), and T1DM plus zinc supplementation (T1DMS). Serum biochemical analysis; tibia histomorphometric, biomechanical, and collagen-content analyses; and femur mRNA expression were evaluated. Relative to T1DM, the zinc-supplemented group showed increased histomorphometric parameters such as TbWi and BAr and decreased TbSp, increased biomechanical parameters (maximum load, stiffness, ultimate strain, and Young’s modulus), and increased type I collagen content. Interestingly, similar values for these parameters were observed between the T1DMS and control groups. These results demonstrate the protective effect of zinc on the maintenance of bone strength and flexibility. In addition, downregulation of OPG, COL1A, and MMP-9 genes was observed in T1DMS, and the anabolic effects of zinc were evidenced by increased OC expression and serum ALP activity, both related to osteoblastogenesis, demonstrating a positive effect on bone formation. In contrast, T1DM showed excessive bone loss, observed through reduced histomorphometric and biomechanical parameters, characterizing diabetes-associated bone loss. The bone loss was also observed through upregulation of OPG, COL1A, and MMP-9 genes. In conclusion, zinc showed a positive effect on the maintenance of bone architecture and biomechanical parameters. Indeed, OC upregulation and control of expression of OPG, COL1A, and MMP-9 mRNAs, even in chronic hyperglycemia, support an anabolic and protective

  11. Solution structure of Ln(III) complexes with macrocyclic ligands through theoretical evaluation of 1H NMR contact shifts.

    PubMed

    Rodríguez-Rodríguez, Aurora; Esteban-Gómez, David; de Blas, Andrés; Rodríguez-Blas, Teresa; Botta, Mauro; Tripier, Raphaël; Platas-Iglesias, Carlos

    2012-12-17

    Herein, we present a new approach that combines DFT calculations and the analysis of Tb(III)-induced (1)H NMR shifts to quantitatively and accurately account for the contact contribution to the paramagnetic shift in Ln(III) complexes. Geometry optimizations of different Gd(III) complexes with macrocyclic ligands were carried out using the hybrid meta-GGA TPSSh functional and a 46 + 4f(7) effective core potential (ECP) for Gd. The complexes investigated include [Ln(Me-DODPA)](+) (H(2)Me-DODPA = 6,6'-((4,10-dimethyl-1,4,7,10-tetraazacyclododecane-1,7-diyl)bis(methylene))dipicolinic acid, [Ln(DOTA)(H(2)O)](-) (H(4)DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate), [Ln(DOTAM)(H(2)O)](3+) (DOTAM = 1,4,7,10- tetrakis[(carbamoyl)methyl]-1,4,7,10-tetraazacyclododecane), and related systems containing pyridyl units (Ln = Gd, Tb). Subsequent all-electron relativistic calculations based on the DKH2 approximation, or small-core ECP calculations, were used to compute the (1)H hyperfine coupling constants (HFCCs) at the ligand nuclei (A(iso) values). The calculated A(iso) values provided direct access to contact contributions to the (1)H NMR shifts of the corresponding Tb(III) complexes under the assumption that Gd and Tb complexes with a given ligand present similar HFCCs. These contact shifts were used to obtain the pseudocontact shifts, which encode structural information as they depend on the position of the nucleus with respect to the lanthanide ion. An excellent agreement was observed between the experimental and calculated pseudocontact shifts using the DFT-optimized geometries as structural models of the complexes in solution, which demonstrates that the computational approach used provides (i) good structural models for the complexes, (ii) accurate HFCCs at the ligand nuclei. The methodology presented in this work can be classified in the context of model-dependent methods, as it relies on the use of a specific molecular structure obtained from DFT

  12. Regioselectively Controlled Synthesis of N-Substituted (Trifluoromethyl)pyrimidin-2(1H)-ones.

    PubMed

    da Silva, Andreia M P W; da Silva, Fabio M; Bonacorso, Helio G; Frizzo, Clarissa P; Martins, Marcos A P; Zanatta, Nilo

    2016-05-01

    A simple and regioselectively controlled method for the preparation of both 1,4- and 1,6-regioisomers of 1-substituted 4(6)-trifluoromethyl-pyrimidin-2(1H)-ones is described. Both regioisomers were synthesized from the cyclocondensation reaction of 4-substituted 1,1,1-trifluoro-4-methoxybut-3-en-2-ones: with nonsymmetric ureas for the 1-substituted 4-(trifluoromethyl)pyrimidin-2(1H)-ones (1,4-isomer) and with nonsymmetric 1-substituted 2-methylisothiourea sulfates for the synthesis of 1-substituted 6-(trifluoromethyl)pyrimidin-2(1H)-ones (1,6-isomer). Each method furnished only the respective isomer in very good yields. The structure of the products was assigned based on the (1)H and (13)C NMR as well as 2D HMBC spectral analysis. PMID:27070191

  13. Lemna minor L. as a model organism for ecotoxicological studies performing 1H NMR fingerprinting.

    PubMed

    Aliferis, Konstantinos A; Materzok, Sylwia; Paziotou, Georgia N; Chrysayi-Tokousbalides, Maria

    2009-08-01

    A validated method applying (1)H NMR fingerprinting for the study of metabolic changes caused in Lemna minor L. by various phytotoxic substances is presented. (1)H NMR spectra of crude extracts from untreated and treated colonies with the herbicides glyphosate, mesotrione, norflurazon, paraquat and the phytotoxin pyrenophorol were subjected to multivariate analyses for detecting differences between groups of treatments. Partial least squares-discriminant analysis (PLS-DA) and hierarchical cluster analysis (HCA) were carried out in order to discriminate and classify treatments according to the observed changes in the metabolome of the plant. Although the compounds at the concentrations used did not cause macroscopically observable symptoms of phytotoxicity, characteristic metabolic changes were detectable by analyzing (1)H NMR spectra. Analyses results revealed that metabonomics applying (1)H NMR fingerprinting is a potential method for the investigation of toxicological effects of xenobiotics on L. minor, and possibly on other duckweed species, helping in the understanding of such interactions. PMID:19443011

  14. Proton-detected 3D {sup 1}H/{sup 13}C/{sup 1}H correlation experiment for structural analysis in rigid solids under ultrafast-MAS above 60 kHz

    SciTech Connect

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy; Nishiyama, Yusuke

    2015-10-28

    A proton-detected 3D {sup 1}H/{sup 13}C/{sup 1}H chemical shift correlation experiment is proposed for the assignment of chemical shift resonances, identification of {sup 13}C-{sup 1}H connectivities, and proximities of {sup 13}C-{sup 1}H and {sup 1}H-{sup 1}H nuclei under ultrafast magic-angle-spinning (ultrafast-MAS) conditions. Ultrafast-MAS is used to suppress all anisotropic interactions including {sup 1}H-{sup 1}H dipolar couplings, while the finite-pulse radio frequency driven dipolar recoupling (fp-RFDR) pulse sequence is used to recouple dipolar couplings among protons and the insensitive nuclei enhanced by polarization transfer technique is used to transfer magnetization between heteronuclear spins. The 3D experiment eliminates signals from non-carbon-bonded protons and non-proton-bonded carbons to enhance spectral resolution. The 2D (F1/F3) {sup 1}H/{sup 1}H and 2D {sup 13}C/{sup 1}H (F2/F3) chemical shift correlation spectra extracted from the 3D spectrum enable the identification of {sup 1}H-{sup 1}H proximity and {sup 13}C-{sup 1}H connectivity. In addition, the 2D (F1/F2) {sup 1}H/{sup 13}C chemical shift correlation spectrum, incorporated with proton magnetization exchange via the fp-RFDR recoupling of {sup 1}H-{sup 1}H dipolar couplings, enables the measurement of proximities between {sup 13}C and even the remote non-carbon-bonded protons. The 3D experiment also gives three-spin proximities of {sup 1}H-{sup 1}H-{sup 13}C chains. Experimental results obtained from powder samples of L-alanine and L-histidine ⋅ H{sub 2}O ⋅ HCl demonstrate the efficiency of the 3D experiment.

  15. One-Pot Synthesis of Substituted Trifluoromethylated 2,3-Dihydro-1H-imidazoles.

    PubMed

    Deutsch, Amrei; Jessen, Christoph; Deutsch, Carl; Karaghiosoff, Konstantin; Hoffmann-Röder, Anja

    2016-07-15

    An operationally simple one-pot reaction for the preparation of a novel class of racemic trifluoromethylated 2,3-dihydro-1H-imidazoles derived from electron-poor N,O-acetals and aryl Grignard reagents is described. In addition, access to highly functionalized 2-trifluoromethyl-2,3-dihydro-1H-imidazoles was accomplished by reaction of N-aryl hemiaminal ethers and N-aryl trifluoroethylamines in the presence of an excess of n-butyllithium. PMID:27359260

  16. MRI T1ρ and T2 mapping for the assessment of articular cartilage changes in patients with medial knee osteoarthritis after hemicallotasis osteotomy

    PubMed Central

    Nakamura, E.; Hirose, J.; Okamoto, N.; Yamabe, S.; Mizuta, H.

    2016-01-01

    Objectives The purpose of this study was to clarify the appearance of the reparative tissue on the articular surface and to analyse the properties of the reparative tissue after hemicallotasis osteotomy (HCO) using MRI T1ρ and T2 mapping. Methods Coronal T1ρ and T2 mapping and three-dimensional gradient-echo images were obtained from 20 subjects with medial knee osteoarthritis. We set the regions of interest (ROIs) on the full-thickness cartilage of the medial femoral condyle (MFC) and medial tibial plateau (MTP) of the knee and measured the cartilage thickness (mm) and T1ρ and T2 relaxation times (ms). Statistical analysis of time-dependent changes in the cartilage thickness and the T1ρ and T2 relaxation times was performed using one-way analysis of variance, and Scheffe’s test was employed for post hoc multiple comparison. Results The cartilage-like repair tissue appeared on the cartilage surface of the medial compartment post-operatively, and the cartilage thickness showed a significant increase between the pre-operative and one-year post-operative time points (MFC; p = 0.003, MTP; p < 0.001). The T1ρ values of the cartilage-like repair tissue showed no difference over time, however, the T2 values showed a significant decrease between the pre-operative and one-year post-operative time points (MFC; p = 0.004, MTP; p = 0.040). Conclusion This study clarified that the fibrocartilage-like repair tissue appeared on the articular surface of the medial compartment after HCO as evidenced by MRI T1ρ and T2 mapping. Cite this article: H. Nishioka, E. Nakamura, J. Hirose, N. Okamoto, S. Yamabe, H. Mizuta. MRI T1ρ and T2 mapping for the assessment of articular cartilage changes in patients with medial knee osteoarthritis after hemicallotasis osteotomy. Bone Joint Res 2016;5:294–300. DOI: 10.1302/2046-3758.57.BJR-2016-0057.R1. PMID:27421285

  17. Determination of glucan phosphorylation using heteronuclear 1H, 13C double and 1H, 13C, 31P triple-resonance NMR spectra.

    PubMed

    Schmieder, Peter; Nitschke, Felix; Steup, Martin; Mallow, Keven; Specker, Edgar

    2013-10-01

    Phosphorylation and dephosphorylation of starch and glycogen are important for their physicochemical properties and also their physiological functions. It is therefore desirable to reliably determine the phosphorylation sites. Heteronuclear multidimensional NMR-spectroscopy is in principle a straightforward analytical approach even for complex carbohydrate molecules. With heterogeneous samples from natural sources, however, the task becomes more difficult because a full assignment of the resonances of the carbohydrates is impossible to obtain. Here, we show that the combination of heteronuclear (1) H,(13) C and (1) H,(13) C,(31) P techniques and information derived from spectra of a set of reference compounds can lead to an unambiguous determination of the phosphorylation sites even in heterogeneous samples. PMID:23913630

  18. Complete 1H, 15N and 13C assignment of trappin-2 and 1H assignment of its two domains, elafin and cementoin.

    PubMed

    Loth, Karine; Alami, Soha Abou Ibrahim; Habès, Chahrazed; Garrido, Solène; Aucagne, Vincent; Delmas, Agnès F; Moreau, Thierry; Zani, Marie-Louise; Landon, Céline

    2016-04-01

    Trappin-2 is a serine protease inhibitor with a very narrow inhibitory spectrum and has significant anti-microbial activities. It is a 10 kDa cationic protein composed of two distinct domains. The N-terminal domain (38 residues) named cementoin is known to be intrinsically disordered when it is not linked to the elafin. The C-terminal domain (57 residues), corresponding to elafin, is a cysteine-rich domain stabilized by four disulfide bridges and is characterized by a flat core and a flexible N-terminal part. To our knowledge, there is no structural data available on trappin-2. We report here the complete (1)H, (15)N and (13)C resonance assignment of the recombinant trappin-2 and the (1)H assignments of cementoin and elafin, under the same experimental conditions. This is the first step towards the 3D structure determination of the trappin-2. PMID:26878852

  19. T1 signal hyperintensity in the sellar region: spectrum of findings.

    PubMed

    Bonneville, Fabrice; Cattin, Françoise; Marsot-Dupuch, Kathlyn; Dormont, Didier; Bonneville, Jean-François; Chiras, Jacques

    2006-01-01

    T1 signal hyperintensity is a common finding at magnetic resonance imaging of the sellar region. However, this signal intensity pattern has different sources, and its significance depends on the clinical context. Normal variations in sellar T1 signal hyperintensity are related to vasopressin storage in the neurohypophysis, the presence of bone marrow in normal and variant anatomic structures, hyperactive hormone secretion in the anterior pituitary lobe (eg, in newborns and pregnant or lactating women), and flow artifacts and magnetic susceptibility effects. Pathologic variations in T1 signal hyperintensity may be related to clotting of blood (in hemorrhagic pituitary adenoma, pituitary apoplexy, Sheehan syndrome, or thrombosed aneurysm) or the presence of a high concentration of protein (Rathke cleft cyst, craniopharyngioma, or mucocele), fat (lipoma, dermoid cyst, lipomatous meningioma), calcification (craniopharyngioma, chondroma, chordoma), or a paramagnetic substance (manganese, melanin). After treatment, T1 signal hyperintensity may result from the presence of materials used for surgical packing (gelatin sponge, fat); from compression of the cavernous sinus and reduction of the venous flow, caused by overpacking of the operative bed; or from hormone hypersecretion by a remnant of normal tissue in the anterior lobe of the pituitary gland. PMID:16418246

  20. An improved error assessment for the GEM-T1 gravitational model

    NASA Technical Reports Server (NTRS)

    Lerch, F. J.; Marsh, J. G.; Klosko, S. M.; Patel, G. B.; Chinn, D. S.; Pavlis, E. C.; Wagner, C. A.

    1991-01-01

    Several tests have been designed to estimate the correct error variances for the GEM-T1 gravitational solution that was derived exclusively from satellite tracking data. The basic method uses both independent and dependent subset data solutions and produces a coefficient-by-coefficient estimate of the model uncertainties. The GEM-T1 errors have been further analyzed using a method based on eigenvalue-eigenvector analysis, which calibrates the entire covariance matrix. Dependent satellite data sets and independent altimetric, resonant satellite, and surface gravity data sets all confirm essentially the same error assessment. The calibration test results yield very stable calibration factors, which vary only by approximately 10 percent over the range of tests performed. Based on these calibrated error estimates, GEM-T1 is a significantly improved solution, which to degree and order 8 is twice as accurate as earlier satellite derived models like GEM-L2. Also, by being complete to degree and order 36, GEM-T1 is more complete and has significantly reduced aliasing effects that were present in previous models.

  1. A new gravitational model for the earth from satellite tracking data - GEM-T1

    NASA Technical Reports Server (NTRS)

    Marsh, J. G.; Lerch, F. J.; Putney, B. H.; Christodoulidis, D. C.; Smith, D. E.

    1988-01-01

    A computation of a terrestrial gravitational field model called the Goddard Earth Model GEM-T1 is discussed and compared to previous models, including the GEM-L2. The software tools were redesigned for the model, allowing for the optimization of the technique of relative data weighting and model estimation used in GEM solutions. The GEM-T1 model provides a simultaneous solution for a gravity model in spherical harmonics complete to degree and order 36, a subset of 66 ocean tidal coefficients for the long-wavelength components of 12 major tides, and 5-day averaged earth rotation and polar motion parameters for the 1980 period on. GEM-T1 was derived from satellite tracking data acquired on 17 different satellites whose inclinations ranged from 15 degrees to polar. A simulation of the TOPEX/POSEIDON orbit using the covariances of the GEM-T1 model was made. Estimated radial error for the simulation was reduced to less than 30 cm rms.

  2. An improved error assessment for the GEM-T1 gravitational model

    NASA Technical Reports Server (NTRS)

    Lerch, F. J.; Marsh, J. G.; Klosko, S. M.; Pavlis, E. C.; Patel, G. B.; Chinn, D. S.; Wagner, C. A.

    1988-01-01

    Several tests were designed to determine the correct error variances for the Goddard Earth Model (GEM)-T1 gravitational solution which was derived exclusively from satellite tracking data. The basic method employs both wholly independent and dependent subset data solutions and produces a full field coefficient estimate of the model uncertainties. The GEM-T1 errors were further analyzed using a method based upon eigenvalue-eigenvector analysis which calibrates the entire covariance matrix. Dependent satellite and independent altimetric and surface gravity data sets, as well as independent satellite deep resonance information, confirm essentially the same error assessment. These calibrations (utilizing each of the major data subsets within the solution) yield very stable calibration factors which vary by approximately 10 percent over the range of tests employed. Measurements of gravity anomalies obtained from altimetry were also used directly as observations to show that GEM-T1 is calibrated. The mathematical representation of the covariance error in the presence of unmodeled systematic error effects in the data is analyzed and an optimum weighting technique is developed for these conditions. This technique yields an internal self-calibration of the error model, a process which GEM-T1 is shown to approximate.

  3. IMPROVED SCORING OF CHEMICAL TRANSFORMATION OF C3H/10T1/2 CELLS

    EPA Science Inventory

    This research program was undertaken to improve the scoring of the transformation by chemical carcinogens of C3H/10T1/2 mouse embryo fibroblasts. (1) A probabilistic view of transformed focus formation in these cells induced by methylcholanthrene (MCA) treatment has been formulat...

  4. Hungarian case with Costello syndrome and translocation t(1,22)

    SciTech Connect

    1995-07-03

    The purpose of this short case report is to document the presence of the Costello syndrome in a Hungarian girl. Clinical manifestations include characteristic facial changes, skeletal involvements, mild mental retardation. Chromosome analysis showed a balanced translocation: 46,XX,t(1,22)(q25,q11). 7 refs., 1 fig.

  5. The cysteine-rich region of T1R3 determines responses to intensely sweet proteins.

    PubMed

    Jiang, Peihua; Ji, Qingzhou; Liu, Zhan; Snyder, Lenore A; Benard, Lumie M J; Margolskee, Robert F; Max, Marianna

    2004-10-22

    A wide variety of chemically diverse compounds taste sweet, including natural sugars such as glucose, fructose, sucrose, and sugar alcohols, small molecule artificial sweeteners such as saccharin and acesulfame K, and proteins such as monellin and thaumatin. Brazzein, like monellin and thaumatin, is a naturally occurring plant protein that humans, apes, and Old World monkeys perceive as tasting sweet but that is not perceived as sweet by other species including New World monkeys, mouse, and rat. It has been shown that heterologous expression of T1R2 plus T1R3 together yields a receptor responsive to many of the above-mentioned sweet tasting ligands. We have determined that the molecular basis for species-specific sensitivity to brazzein sweetness depends on a site within the cysteine-rich region of human T1R3. Other mutations in this region of T1R3 affected receptor activity toward monellin, and in some cases, overall efficacy to multiple sweet compounds, implicating this region as a previously unrecognized important determinant of sweet receptor function. PMID:15299024

  6. Water-mediated recognition of t1-adenosine anchors Argonaute2 to microRNA targets

    PubMed Central

    Schirle, Nicole T; Sheu-Gruttadauria, Jessica; Chandradoss, Stanley D; Joo, Chirlmin; MacRae, Ian J

    2015-01-01

    MicroRNAs (miRNAs) direct post-transcriptional regulation of human genes by guiding Argonaute proteins to complementary sites in messenger RNAs (mRNAs) targeted for repression. An enigmatic feature of many conserved mammalian miRNA target sites is that an adenosine (A) nucleotide opposite miRNA nucleotide-1 confers enhanced target repression independently of base pairing potential to the miRNA. In this study, we show that human Argonaute2 (Ago2) possesses a solvated surface pocket that specifically binds adenine nucleobases in the 1 position (t1) of target RNAs. t1A nucleotides are recognized indirectly through a hydrogen-bonding network of water molecules that preferentially interacts with the N6 amine on adenine. t1A nucleotides are not utilized during the initial binding of Ago2 to its target, but instead function by increasing the dwell time on target RNA. We also show that N6 adenosine methylation blocks t1A recognition, revealing a possible mechanism for modulation of miRNA target site potency. DOI: http://dx.doi.org/10.7554/eLife.07646.001 PMID:26359634

  7. Modified nucleotides in T1 RNase oligonucleotides of 18S ribosomal RNA of the Novikoff hepatoma.

    PubMed

    Choi, Y C; Busch, H

    1978-06-27

    The primary structure of 18S rRNA of the Novikoff hepatoma cells was investigated. Regardless of whether the primary sequence of 18S rRNA is finally determined by RNA sequencing methods or DNA sequencing methods, it is important to identify numbers and types of the modified nucleotides and accordingly the present study was designed to localize the modified regions in T1 RNase derived oligonucleotide. Modified nucleotides found in 66 different oligonucleotide sequences included 2 m62A, 1 m6A, 1 m7G, 1m1cap3psi, 7 Cm, 13 Am, 9 Gm, 11 Um, and 38 psi residues. A number of these modified nucleotides are now placed in defined sequences of T1 RNase oligonucleotides which are now being searched for in larger fragments derived from partial T1 RNase digests of 18S rRNA. Improved homochromatography fingerprinting (Choi et al. (1976) Cancer Res. 36, 4301) of T1 RNase derived oligonucleotides provided a distinctive pattern for 18S rRNA of Novikoff hepatoma ascites cells. The 116 spots obtained by homochromatography contain 176 oligonucleotide sequences. PMID:209819

  8. Pollution reduction technology program for small jet aircraft engines: Class T1

    NASA Technical Reports Server (NTRS)

    Bruce, T. W.; Davis, F. G.; Mongia, H. C.

    1977-01-01

    Small jet aircraft engines (EPA class T1, turbojet and turbofan engines of less than 35.6 kN thrust) were evaluated with the objective of attaining emissions reduction consistent with performance constraints. Configurations employing the technological advances were screened and developed through full scale rig testing. The most promising approaches in full-scale engine testing were evaluated.

  9. Metabolic T1 dynamics and longitudinal relaxation enhancement in vivo at ultrahigh magnetic fields on ischemia.

    PubMed

    Shemesh, Noam; Rosenberg, Jens T; Dumez, Jean-Nicolas; Grant, Samuel C; Frydman, Lucio

    2014-11-01

    Interruptions in cerebral blood flow may lead to devastating neural outcomes. Magnetic resonance has a central role in diagnosing and monitoring these insufficiencies, as well as in understanding their underlying metabolic consequences. Magnetic resonance spectroscopy (MRS) in particular can probe ischemia via the signatures of endogenous metabolites including lactic acid (Lac), N-acetylaspartate, creatine (Cre), and cholines. Typically, MRS reports on these metabolites' concentrations. This study focuses on establishing the potential occurrence of in vivo longitudinal relaxation enhancement (LRE) effects-a phenomenon involving a reduction of the apparent T1 with selective bandwidth excitations- in a rat stroke model at 21.1 T. Statistically significant reductions in Cre's apparent T1s were observed at all the examined post-ischemia time points for both ipsi- and contralateral hemispheres, thereby establishing the existence of LREs for this metabolite in vivo. Ischemia-dependent LRE trends were also noted for Lac in the ipsilateral hemisphere only 24 hours after ischemia. Metabolic T1s were also found to vary significantly as a function of post-stroke recovery time, with the most remarkable and rapid changes observed for Lac T1s. The potential of such measurements to understand stroke at a molecular level and assist in its diagnosis, is discussed. PMID:25204392

  10. Metabolic T1 dynamics and longitudinal relaxation enhancement in vivo at ultrahigh magnetic fields on ischemia

    PubMed Central

    Shemesh, Noam; Rosenberg, Jens T; Dumez, Jean-Nicolas; Grant, Samuel C; Frydman, Lucio

    2014-01-01

    Interruptions in cerebral blood flow may lead to devastating neural outcomes. Magnetic resonance has a central role in diagnosing and monitoring these insufficiencies, as well as in understanding their underlying metabolic consequences. Magnetic resonance spectroscopy (MRS) in particular can probe ischemia via the signatures of endogenous metabolites including lactic acid (Lac), N-acetylaspartate, creatine (Cre), and cholines. Typically, MRS reports on these metabolites' concentrations. This study focuses on establishing the potential occurrence of in vivo longitudinal relaxation enhancement (LRE) effects—a phenomenon involving a reduction of the apparent T1 with selective bandwidth excitations— in a rat stroke model at 21.1 T. Statistically significant reductions in Cre's apparent T1s were observed at all the examined post-ischemia time points for both ipsi- and contralateral hemispheres, thereby establishing the existence of LREs for this metabolite in vivo. Ischemia-dependent LRE trends were also noted for Lac in the ipsilateral hemisphere only 24 hours after ischemia. Metabolic T1s were also found to vary significantly as a function of post-stroke recovery time, with the most remarkable and rapid changes observed for Lac T1s. The potential of such measurements to understand stroke at a molecular level and assist in its diagnosis, is discussed. PMID:25204392

  11. Genetic deletion of trkB.T1 increases neuromuscular function

    PubMed Central

    Dorsey, Susan G.; Lovering, Richard M.; Renn, Cynthia L.; Leitch, Carmen C.; Liu, Xinyue; Tallon, Luke J.; Sadzewicz, Lisa DeShong; Pratap, Abhishek; Ott, Sandra; Sengamalay, Naomi; Jones, Kristie M.; Barrick, Colleen; Fulgenzi, Gianluca; Becker, Jodi; Voelker, Kevin; Talmadge, Robert; Harvey, Brandon K.; Wyatt, Ryan M.; Vernon-Pitts, Elizabeth; Zhang, Chao; Shokat, Kevan; Fraser-Liggett, Claire; Balice-Gordon, Rita J.; Tessarollo, Lino

    2012-01-01

    Neurotrophin-dependent activation of the tyrosine kinase receptor trkB.FL modulates neuromuscular synapse maintenance and function; however, it is unclear what role the alternative splice variant, truncated trkB (trkB.T1), may have in the peripheral neuromuscular axis. We examined this question in trkB.T1 null mice and demonstrate that in vivo neuromuscular performance and nerve-evoked muscle tension are significantly increased. In vitro assays indicated that the gain-in-function in trkB.T1−/− animals resulted specifically from an increased muscle contractility, and increased electrically evoked calcium release. In the trkB.T1 null muscle, we identified an increase in Akt activation in resting muscle as well as a significant increase in trkB.FL and Akt activation in response to contractile activity. On the basis of these findings, we conclude that the trkB signaling pathway might represent a novel target for intervention across diseases characterized by deficits in neuromuscular function. PMID:21865582

  12. Deformations of T 1 ,1 as Yang-Baxter sigma models

    NASA Astrophysics Data System (ADS)

    Crichigno, P. Marcos; Matsumoto, Takuya; Yoshida, Kentaroh

    2014-12-01

    We consider a family of deformations of T 1,1 in the Yang-Baxter sigma model approach. We first discuss a supercoset description of T 1,1, which makes manifest the full symmetry of the space and leads to the standard Sasaki-Einstein metric. Next, we consider three-parameter deformations of T 1,1 by using classical r-matrices satisfying the classical Yang-Baxter equation (CYBE). The resulting metric and NS-NS two-form agree exactly with the ones obtained via TsT transformations, and contain the Lunin-Maldacena background as a special case. It is worth noting that for AdS5 × T 1,1 , classical integrability for the full sector has been argued to be lost. Hence our result indicates that the Yang-Baxter sigma model approach is applicable even for non-integrable cosets. This observation suggests that the gravity/CYBE correspondence can be extended beyond integrable cases.

  13. A comparative analysis of microgravity and earth grown thermostable T1 lipase crystals using HDPCG apparatus.

    PubMed

    Abd Rahman, Raja N Z R; Ali, Mohd S Mohamad; Sugiyama, Shigeru; Leow, Adam T C; Inoue, Tsuyoshi; Basri, Mahiran; Salleh, Abu B; Matsumura, Hiroyoshi

    2015-01-01

    Geobacillus zalihae sp. nov., which produces a putative thermostable lipase, represents a novel species, with type strain T1. The characterisation of this intrinsically thermostable T1 lipase either physicochemically or structurally is an important task. The crystallisation of T1lipase in space was carried out using a High-Density Protein Crystal Growth (HDPCG) apparatus with the vapour diffusion method, and X-ray diffraction data were collected. The microgravity environment has improved the size and quality of the crystals as compared to earth grown crystal. The effect of microgravity on the crystallisation of T1 lipase was clearly evidenced by the finer atomic details at 1.35 A resolution. Better electron densities were observed overall compared with the Earth-grown crystals, and comparison shows the subtle but distinct conformations around Na(+) ion binding site stabilized via cation-π interactions. This approach could be useful for solving structure and function of lipases towards exploiting its potentials to various industrial applications. PMID:25329331

  14. Dissection of the structural and functional role of a conserved hydration site in RNase T1.

    PubMed Central

    Langhorst, U.; Loris, R.; Denisov, V. P.; Doumen, J.; Roose, P.; Maes, D.; Halle, B.; Steyaert, J.

    1999-01-01

    The reoccurrence of water molecules in crystal structures of RNase T1 was investigated. Five waters were found to be invariant in RNase T1 as well as in six other related fungal RNases. The structural, dynamical, and functional characteristics of one of these conserved hydration sites (WAT1) were analyzed by protein engineering, X-ray crystallography, and (17)O and 2H nuclear magnetic relaxation dispersion (NMRD). The position of WAT1 and its surrounding hydrogen bond network are unaffected by deletions of two neighboring side chains. In the mutant Thr93Gln, the Gln93N epsilon2 nitrogen replaces WAT1 and participates in a similar hydrogen bond network involving Cys6, Asn9, Asp76, and Thr91. The ability of WAT1 to form four hydrogen bonds may explain why evolution has preserved a water molecule, rather than a side-chain atom, at the center of this intricate hydrogen bond network. Comparison of the (17)O NMRD profiles from wild-type and Thr93Gln RNase T1 yield a mean residence time of 7 ns at 27 degrees C and an orientational order parameter of 0.45. The effects of mutations around WAT1 on the kinetic parameters of RNase T1 are small but significant and probably relate to the dynamics of the active site. PMID:10211818

  15. [(1)H] magnetic resonance spectroscopy of urine: diagnosis of a guanidinoacetate methyl transferase deficiency case.

    PubMed

    Tassini, Maria; Zannolli, Raffaella; Buoni, Sabrina; Engelke, Udo; Vivi, Antonio; Valensin, Gianni; Salomons, Gajja S; De Nicola, Anna; Strambi, Mirella; Monti, Lucia; Morava, Eva; Wevers, Ron A; Hayek, Joseph

    2010-01-01

    For the first time, the use of urine [(1)H] magnetic resonance spectroscopy has allowed the detection of 1 case of guanidinoacetate methyl transferase in a database sample of 1500 pediatric patients with a diagnosis of central nervous system impairment of unknown origin. The urine [(1)H] magnetic resonance spectroscopy of a 9-year-old child, having severe epilepsy and nonprogressive mental and motor retardation with no apparent cause, revealed a possible guanidinoacetic acid increase. The definitive assignment of guanidinoacetic acid was checked by addition of pure substance to the urine sample and by measuring [(1)H]-[(1)H] correlation spectroscopy. Diagnosis of guanidinoacetate methyl transferase deficiency was further confirmed by liquid chromatography-mass spectrometry, brain [(1)H] magnetic resonance spectroscopy, and mutational analysis of the guanidinoacetate methyl transferase gene. The replacement therapy was promptly started and, after 1 year, the child was seizure free. We conclude that for this case, urine [(1)H] magnetic resonance spectroscopy screening was able to diagnose guanidinoacetate methyl transferase deficiency. PMID:19461121

  16. New Magnetic Resonance Imaging Index for Renal Fibrosis Assessment: A Comparison between Diffusion-Weighted Imaging and T1 Mapping with Histological Validation

    PubMed Central

    Friedli, I.; Crowe, L. A.; Berchtold, L.; Moll, S.; Hadaya, K.; de Perrot, T.; Vesin, C.; Martin, P.-Y.; de Seigneux, S.; Vallée, J.-P.

    2016-01-01

    A need exists to noninvasively assess renal interstitial fibrosis, a common process to all kidney diseases and predictive of renal prognosis. In this translational study, Magnetic Resonance Imaging (MRI) T1 mapping and a new segmented Diffusion-Weighted Imaging (DWI) technique, for Apparent Diffusion Coefficient (ADC), were first compared to renal fibrosis in two well-controlled animal models to assess detection limits. Validation against biopsy was then performed in 33 kidney allograft recipients (KARs). Predictive MRI indices, ΔT1 and ΔADC (defined as the cortico-medullary differences), were compared to histology. In rats, both T1 and ADC correlated well with fibrosis and inflammation showing a difference between normal and diseased kidneys. In KARs, MRI indices were not sensitive to interstitial inflammation. By contrast, ΔADC outperformed ΔT1 with a stronger negative correlation to fibrosis (R2 = 0.64 against R2 = 0.29 p < 0.001). ΔADC tends to negative values in KARs harboring cortical fibrosis of more than 40%. Using a discriminant analysis method, the ΔADC, as a marker to detect such level of fibrosis or higher, led to a specificity and sensitivity of 100% and 71%, respectively. This new index has potential for noninvasive assessment of fibrosis in the clinical setting. PMID:27439482

  17. Dual-mode T1 and T2 magnetic resonance imaging contrast agent based on ultrasmall mixed gadolinium-dysprosium oxide nanoparticles: synthesis, characterization, and in vivo application.

    PubMed

    Tegafaw, Tirusew; Xu, Wenlong; Ahmad, Md Wasi; Baeck, Jong Su; Chang, Yongmin; Bae, Ji Eun; Chae, Kwon Seok; Kim, Tae Jeong; Lee, Gang Ho

    2015-09-11

    A new type of dual-mode T1 and T2 magnetic resonance imaging (MRI) contrast agent based on mixed lanthanide oxide nanoparticles was synthesized. Gd(3+) ((8)S7/2) plays an important role in T1 MRI contrast agents because of its large electron spin magnetic moment resulting from its seven unpaired 4f-electrons, and Dy(3+) ((6)H15/2) has the potential to be used in T2 MRI contrast agents because of its very large total electron magnetic moment: among lanthanide oxide nanoparticles, Dy2O3 nanoparticles have the largest magnetic moments at room temperature. Using these properties of Gd(3+) and Dy(3+) and their oxide nanoparticles, ultrasmall mixed gadolinium-dysprosium oxide (GDO) nanoparticles were synthesized and their potential to act as a dual-mode T1 and T2 MRI contrast agent was investigated in vitro and in vivo. The D-glucuronic acid coated GDO nanoparticles (davg = 1.0 nm) showed large r1 and r2 values (r2/r1 ≈ 6.6) and as a result clear dose-dependent contrast enhancements in R1 and R2 map images. Finally, the dual-mode imaging capability of the nanoparticles was confirmed by obtaining in vivo T1 and T2 MR images. PMID:26291827

  18. New Magnetic Resonance Imaging Index for Renal Fibrosis Assessment: A Comparison between Diffusion-Weighted Imaging and T1 Mapping with Histological Validation.

    PubMed

    Friedli, I; Crowe, L A; Berchtold, L; Moll, S; Hadaya, K; de Perrot, T; Vesin, C; Martin, P-Y; de Seigneux, S; Vallée, J-P

    2016-01-01

    A need exists to noninvasively assess renal interstitial fibrosis, a common process to all kidney diseases and predictive of renal prognosis. In this translational study, Magnetic Resonance Imaging (MRI) T1 mapping and a new segmented Diffusion-Weighted Imaging (DWI) technique, for Apparent Diffusion Coefficient (ADC), were first compared to renal fibrosis in two well-controlled animal models to assess detection limits. Validation against biopsy was then performed in 33 kidney allograft recipients (KARs). Predictive MRI indices, ΔT1 and ΔADC (defined as the cortico-medullary differences), were compared to histology. In rats, both T1 and ADC correlated well with fibrosis and inflammation showing a difference between normal and diseased kidneys. In KARs, MRI indices were not sensitive to interstitial inflammation. By contrast, ΔADC outperformed ΔT1 with a stronger negative correlation to fibrosis (R(2) = 0.64 against R(2) = 0.29 p < 0.001). ΔADC tends to negative values in KARs harboring cortical fibrosis of more than 40%. Using a discriminant analysis method, the ΔADC, as a marker to detect such level of fibrosis or higher, led to a specificity and sensitivity of 100% and 71%, respectively. This new index has potential for noninvasive assessment of fibrosis in the clinical setting. PMID:27439482

  19. Quantitation of normal metabolite concentrations in six brain regions by in-vivo 1H-MR spectroscopy

    PubMed Central

    Minati, Ludovico; Aquino, Domenico; Bruzzone, Maria Grazia; Erbetta, Alessandra

    2010-01-01

    This study examined the concentrations of brain metabolites visible to in-vivo 1H-Magnetic Resonance Spectroscopy (1H-MRS) at 1.5 T in a sample of 28 normal subjects. Quantitation was attempted for inositol compounds, choline units, total creatine and N-acetyl moieties, using open-source software. Six brain regions were considered: frontal and parietal white matter, medial temporal lobe, thalamus, pons and cerebellum. Absolute concentrations were derived using tissue water as an internal reference and using an external reference; metabolite signal intensity ratios with respect to creatine were also calculated. The inter-individual variability was smaller for absolute concentrations (internal reference) as compared to that for signal intensity ratios. Significant regional variability in concentration was found for all metabolites, indicating that separate normative values are needed for different brain regions. The values obtained in this study can be used as reference in future studies, provided the same methodology is followed; it is confirmed that despite unsuccessful attempts in the past, smaller coefficients of variation can indeed be obtained through absolute quantification. PMID:20927223

  20. Higher energy electronic transitions of HC(2n+1)H+ (n=2-7) and HC(2n+1)H (n=4-7) in neon matrices.

    PubMed

    Fulara, Jan; Nagy, Adam; Garkusha, Iryna; Maier, John P

    2010-07-14

    Electronic absorption spectra of linear HC(2n+1)H(+) (n=2-7) were recorded in 6 K neon matrices following their mass-selective deposition. Four new electronic band systems are identified; the strongest E (2)Pi(g/u)<--X (2)Pi(u/g) lies in the UV and the second most intense C (2)Pi(g/u)<--X (2)Pi(u/g) is located in the visible range. The known A (2)Pi(g/u)<--X (2)Pi(u/g) absorption is an order of magnitude weaker than C (2)Pi(g/u)<--X (2)Pi(u/g). Transitions to the B and D states are also discussed. The wavelengths of the HC(2n+1)H(+) (n=2-7) electronic systems obey a linear relation as a function of the size of the cations, similar to other carbon chains. The B (3)Sigma(u)(-)<--X (3)Sigma(g)(-) transition in the UV of neutral HC(2n+1)H (n=4-7) has also been identified upon photobleaching of the cations trapped in the matrices. PMID:20632752

  1. Bisphosphonate-anchored PEGylation and radiolabeling of superparamagnetic iron oxide: long-circulating nanoparticles for in vivo multimodal (T1 MRI-SPECT) imaging.

    PubMed

    Sandiford, Lydia; Phinikaridou, Alkystis; Protti, Andrea; Meszaros, Levente K; Cui, Xianjin; Yan, Yong; Frodsham, George; Williamson, Peter A; Gaddum, Nicholas; Botnar, René M; Blower, Philip J; Green, Mark A; de Rosales, Rafael T M

    2013-01-22

    The efficient delivery of nanomaterials to specific targets for in vivo biomedical imaging is hindered by rapid sequestration by the reticuloendothelial system (RES) and consequent short circulation times. To overcome these two problems, we have prepared a new stealth PEG polymer conjugate containing a terminal 1,1-bisphosphonate (BP) group for strong and stable binding to the surface of ultrasmall-superparamagnetic oxide nanomaterials (USPIOs). This polymer, PEG(5)-BP, can be used to exchange the hydrophobic surfactants commonly used in the synthesis of USPIOs very efficiently and at room temperature using a simple method in 1 h. The resulting nanoparticles, PEG(5)-BP-USPIOs are stable in water or saline for at least 7 months and display a near-zero ζ-potential at neutral pH. The longitudinal (r(1)) and transverse (r(2)) relaxivities were measured at a clinically relevant magnetic field (3 T), revealing a high r(1) of 9.5 mM(-1) s(-1) and low r(2)/r(1) ratio of 2.97, making these USPIOs attractive as T1-weighted MRI contrast agents at high magnetic fields. The strong T1-effect was demonstrated in vivo, revealing that PEG(5)-BP-USPIOs remain in the bloodstream and enhance its signal 6-fold, allowing the visualization of blood vessels and vascular organs with high spatial definition. Furthermore, the optimal relaxivity properties allow us to inject a dose 4 times lower than with other USPIOs. PEG(5)-BP-USPIOs can also be labeled using a radiolabeled-BP for visualization with single photon emission computed tomography (SPECT), and thus affording dual-modality contrast. The SPECT studies confirmed low RES uptake and long blood circulation times (t(1/2) = 2.97 h). These results demonstrate the potential of PEG(5)-BP-USPIOs for the development of targeted multimodal imaging agents for molecular imaging. PMID:23194247

  2. Bisphosphonate-Anchored PEGylation and Radiolabeling of Superparamagnetic Iron Oxide: Long-Circulating Nanoparticles for in Vivo Multimodal (T1 MRI-SPECT) Imaging

    PubMed Central

    2012-01-01

    The efficient delivery of nanomaterials to specific targets for in vivo biomedical imaging is hindered by rapid sequestration by the reticuloendothelial system (RES) and consequent short circulation times. To overcome these two problems, we have prepared a new stealth PEG polymer conjugate containing a terminal 1,1-bisphosphonate (BP) group for strong and stable binding to the surface of ultrasmall-superparamagnetic oxide nanomaterials (USPIOs). This polymer, PEG(5)-BP, can be used to exchange the hydrophobic surfactants commonly used in the synthesis of USPIOs very efficiently and at room temperature using a simple method in 1 h. The resulting nanoparticles, PEG(5)-BP-USPIOs are stable in water or saline for at least 7 months and display a near-zero ζ-potential at neutral pH. The longitudinal (r1) and transverse (r2) relaxivities were measured at a clinically relevant magnetic field (3 T), revealing a high r1 of 9.5 mM–1 s–1 and low r2/r1 ratio of 2.97, making these USPIOs attractive as T1-weighted MRI contrast agents at high magnetic fields. The strong T1-effect was demonstrated in vivo, revealing that PEG(5)-BP-USPIOs remain in the bloodstream and enhance its signal 6-fold, allowing the visualization of blood vessels and vascular organs with high spatial definition. Furthermore, the optimal relaxivity properties allow us to inject a dose 4 times lower than with other USPIOs. PEG(5)-BP-USPIOs can also be labeled using a radiolabeled-BP for visualization with single photon emission computed tomography (SPECT), and thus affording dual-modality contrast. The SPECT studies confirmed low RES uptake and long blood circulation times (t1/2 = 2.97 h). These results demonstrate the potential of PEG(5)-BP-USPIOs for the development of targeted multimodal imaging agents for molecular imaging. PMID:23194247

  3. Posttherapeutic change in portal-systemic circulation investigated by T1-201 per-rectal administration

    SciTech Connect

    Tonami, N.; Nakajima, K.; Watanabe, N.; Yokoyama, K.; Seto, M.; Seki, H.; Koizumi, K.; Hisada, K.; Kanai, M.; Hinoue, Y.

    1984-01-01

    A noninvasive method of T1-201 per-rectal administration was performed in patients with esophageal varices to investigate the changes of portal-systemic circulation after treatment. One mCi of T1-201 chloride was given rectally and scintigram and heart/liver uptake ratio at 60 min. after administration (H/L) were investigated before and after sclerosing therapy of esophageal varices by direct injection of ethanolamine oleate under endoscopic guidance (9 patients, 13 cases) and splenic artery emobilization therapy with gelatin sponge block (6 patients). The mean value of H/L was decreased from 1.22 +- 0.21 to 0.96 +- 0.34 in 9 cases who underwent successful varices sclerosing therapy (p<0.05) and marked decrease of H/L and scintigraphic change were observed in 2 cases, but there were 7 cases showing no or a little change, while in 4 cases of unsuccessful sclerosing therapy, H/L was not significantly changed. The mean value of H/L was decreased from 1.15 +- 0.26 to 0.84 +- 0.27 in 6 patients who underwent splenic artery embolization therapy (p<0.005) but there was no significant correlation between H/L change rate and embolization volume of spleen. From these results, the authors understand that portal-systematic shunting greatly depends on esophageal varices in cases showing highly decreased H/L after sclerosing therapy and does not much depend on esophageal varices in cases showing no or a little change in H/L. This method seems to be useful in evaluating pathophysiological changes in portal-systemic shunting by treatments of portal circulation.

  4. Water 1H relaxation dispersion analysis on a nitroxide radical provides information on the maximal signal enhancement in Overhauser dynamic nuclear polarization experiments.

    PubMed

    Bennati, Marina; Luchinat, Claudio; Parigi, Giacomo; Türke, Maria-Teresa

    2010-06-14

    Water (1)H relaxation rate measurements of (15)N-(2)H-TEMPONE solutions at temperatures ranging from 298 to 328 K have been performed as a function of magnetic field from 0.00023 to 9.4 T, corresponding to (1)H Larmor frequencies of 0.01 to 400 MHz. The relaxation profiles were analyzed according to the full theory for dipolar and contact relaxation, and used to estimate the coupling factor responsible for observed solution DNP effects. The experimental DNP enhancement at (1)H Larmor frequency of 15 MHz obtained by saturating one of the lines of the (15)N doublet is only ca. 20% lower than the limiting value predicted from the relaxation data, indicating that the experimental DNP setup is nearly optimal, the residual discrepancy arising from incomplete saturation of the other line. PMID:20458388

  5. Charge imbalance and bilayer two-dimensional electron systems at νT=1

    NASA Astrophysics Data System (ADS)

    Champagne, A. R.; Finck, A. D. K.; Eisenstein, J. P.; Pfeiffer, L. N.; West, K. W.

    2008-11-01

    We use interlayer tunneling to study bilayer two-dimensional electron systems at νT=1 over a wide range of charge-density imbalance Δν=ν1-ν2 between the two layers. We find that the strongly enhanced tunneling associated with the coherent excitonic νT=1 phase at small layer separation can survive at least up to an imbalance of Δν=0.5 , i.e., (ν1,ν2)=(3/4,1/4) . Phase transitions between the excitonic νT=1 state and bilayer states which lack significant interlayer correlations can be induced in three different ways: by increasing the effective interlayer spacing d/ℓ , the temperature T , or the charge imbalance Δν . We observe that close to the phase boundary the coherent νT=1 phase can be absent at Δν=0 , present at intermediate Δν , and then absent again at large Δν , thus indicating an intricate phase competition between it and incoherent quasi-independent layer states. At zero imbalance, the critical d/ℓ shifts linearly with temperature, while at Δν=1/3 the critical d/ℓ is only weakly dependent on T . At Δν=1/3 we report on an observation of a direct phase transition between the coherent excitonic νT=1 bilayer integer quantum Hall phase and the pair of single-layer fractional quantized Hall states at ν1=2/3 and ν2=1/3 .

  6. Fast and robust 3D T1 mapping using spiral encoding and steady RF excitation at 7 T: application to cardiac manganese enhanced MRI (MEMRI) in mice.

    PubMed

    Castets, Charles R; Ribot, Emeline J; Lefrançois, William; Trotier, Aurélien J; Thiaudière, Eric; Franconi, Jean-Michel; Miraux, Sylvain

    2015-07-01

    Mapping longitudinal relaxation times in 3D is a promising quantitative and non-invasive imaging tool to assess cardiac remodeling. Few methods are proposed in the literature allowing us to perform 3D T1 mapping. These methods often require long scan times and use a low number of 3D images to calculate T1 . In this project, a fast 3D T1 mapping method using a stack-of-spirals sampling scheme and regular RF pulse excitation at 7 T is presented. This sequence, combined with a newly developed fitting procedure, allowed us to quantify T1 of the whole mouse heart with a high spatial resolution of 208 × 208 × 315 µm(3) in 10-12 min acquisition time. The sensitivity of this method for measuring T1 variations was demonstrated on mouse hearts after several injections of manganese chloride (doses from 25 to 150 µmol kg(-1) ). T1 values were measured in vivo in both pre- and post-contrast experiments. This protocol was also validated on ischemic mice to demonstrate its efficiency to visualize tissue damage induced by a myocardial infarction. This study showed that combining spiral gradient shape and steady RF excitation enabled fast and robust 3D T1 mapping of the entire heart with a high spatial resolution. PMID:25989986

  7. 1H NMR- based metabolomics approaches as non- invasive tools for diagnosis of endometriosis

    PubMed Central

    Ghazi, Negar; Arjmand, Mohammad; Akbari, Ziba; Mellati, Ali Owsat; Saheb-Kashaf, Hamid; Zamani, Zahra

    2016-01-01

    Background: So far, non-invasive diagnostic approaches such as ultrasound, magnetic resonance imaging, or blood tests do not have sufficient diagnostic power for endometriosis disease. Lack of a non-invasive diagnostic test contributes to the long delay between onset of symptoms and diagnosis of endometriosis. Objective: The present study focuses on the identification of predictive biomarkers in serum by pattern recognition techniques and uses partial least square discriminant analysis, multi-layer feed forward artificial neural networks (ANNs) and quadratic discriminant analysis (QDA) modeling tools for the early diagnosis of endometriosis in a minimally invasive manner by 1H- NMR based metabolomics. Materials and Methods: This prospective cohort study was done in Pasteur Institute, Iran in June 2013. Serum samples of 31 infertile women with endometriosis (stage II and III) who confirmed by diagnostic laparoscopy and 15 normal women were collected and analyzed by nuclear magnetic resonance spectroscopy. The model was built by using partial least square discriminant analysis, QDA, and ANNs to determine classifier metabolites for early prediction risk of disease. Results: The levels of 2- methoxyestron, 2-methoxy estradiol, dehydroepiandrostion androstendione, aldosterone, and deoxy corticosterone were enhanced significantly in infertile group. While cholesterol and primary bile acids levels were decreased. QDA model showed significant difference between two study groups. Positive and negative predict value levels obtained about 71% and 78%, respectively. ANNs provided also criteria for detection of endometriosis. Conclusion: The QDA and ANNs modeling can be used as computational tools in noninvasive diagnose of endometriosis. However, the model designed by QDA methods is more efficient compared to ANNs in diagnosis of endometriosis patients. PMID:27141542

  8. Classification of iron-sulfur cores in ferredoxins by 1H nuclear magnetic resonance spectroscopy.

    PubMed

    Nagayama, K; Ozaki, Y; Kyogoku, Y; Hase, T; Matsubara, H

    1983-09-01

    A 1H nuclear magnetic resonance (NMR) study was carried out on various ferredoxins which possess one of three types of iron-sulfur clusters, (2Fe-2S), (3Fe-3S), or (4Fe-4S). In the isolated form, (2Fe-2S) ferredoxins from spinach (Spinacea oleracia), pokeweed (Phytolacca americana), a blue-green alga (Spirulina platensis), and a halobacterium (Halobacterium halobium) exhibited two broad resonances common in chemical shift at the region downfield of 10 ppm. In their reduced forms, seven contact-shifted resonances appeared spread over 30 ppm. Although the positions of the contact-shifted resonances in the reduced state differed among the four, a common trend in the temperature dependence of their resonance positions was recognized. Two (4Fe-4S) ferredoxins from Bacillus stearothermophilus and Bacillus thermoproteolyticus exhibited almost indistinguishable spectral patterns in both the oxidized and reduced forms. The ferricyanide-treated ferredoxins of B. stearothermophilus and B. thermoproteolyticus showed characteristic contact-shifted resonances distinct from the spectra of the original (4Fe-4S) ferredoxins. This corresponds to the recent finding of the interconversion of (4Fe-4S) and (3Fe-3S) clusters with ferricyanide in the ferredoxin. Based on our data together with reported NMR data on other ferredoxins, contact-shift resonances of three types of clusters were tabulated. The reliability of NMR classification increases when we compare the NMR spectra of a ferredoxin with the classification standards at the two redox states. Moreover, not only the absolute values of the chemical shifts of contact-shifted resonances but also their temperature dependence give distinctive information applicable to iron core identification. PMID:6417123

  9. Evaluation of 1H NMR metabolic profiling using biofluid mixture design.

    PubMed

    Athersuch, Toby J; Malik, Shahid; Weljie, Aalim; Newton, Jack; Keun, Hector C

    2013-07-16

    A strategy for evaluating the performance of quantitative spectral analysis tools in conditions that better approximate background variation in a metabonomics experiment is presented. Three different urine samples were mixed in known proportions according to a {3, 3} simplex lattice experimental design and analyzed in triplicate by 1D (1)H NMR spectroscopy. Fifty-four urinary metabolites were subsequently quantified from the sample spectra using two methods common in metabolic profiling studies: (1) targeted spectral fitting and (2) targeted spectral integration. Multivariate analysis using partial least-squares (PLS) regression showed the latent structure of the spectral set recapitulated the experimental mixture design. The goodness-of-prediction statistic (Q(2)) of each metabolite variable in a PLS model was calculated as a metric for the reliability of measurement, across the sample compositional space. Several metabolites were observed to have low Q(2) values, largely as a consequence of their spectral resonances having low s/n or strong overlap with other sample components. This strategy has the potential to allow evaluation of spectral features obtained from metabolic profiling platforms in the context of the compositional background found in real biological sample sets, which may be subject to considerable variation. We suggest that it be incorporated into metabolic profiling studies to improve the estimation of matrix effects that confound accurate metabolite measurement. This novel method provides a rational basis for exploiting information from several samples in an efficient manner and avoids the use of multiple spike-in authentic standards, which may be difficult to obtain. PMID:23730812

  10. Antiplasmodial Drugs in the Gas Phase: A CID and DFT Study of Quinolon-4( 1H)-Imine Derivatives

    NASA Astrophysics Data System (ADS)

    Amorim Madeira, Paulo J.; Sitoe, Ana Raquel Fernandes; Gonçalves, Daniel; Rodrigues, Tiago; Guedes, Rita C.; Lopes, Francisca; Moreira, Rui; Bronze, M. Rosário

    2014-09-01

    The gas-phase behavior of 12 quinolon-4( 1H)-imine derivatives with antiplasmodial activity was investigated using electrospray ionization tandem mass spectrometry together with collision induced dissociation and density functional theory (DFT) calculations. The most probable protonation site was predicted by calculating the proton affinity (PA) values for each possible protonation site and it was found to be the imine nitrogen for all compounds under study. Fragmentation pathways of the protonated molecules were proposed and the assignment of product ion structures was performed taking into account theoretical calculations. The nature of the quinoline substituent was found to influence the gas-phase behavior of the compounds under study. The data acquired allowed to bracket the proton affinity of the quinolin-4-imine scaffold, which can be a useful starting point to choose appropriate references for determining PA values of this scaffold.

  11. Determination of nuclear distances and chemical-shift anisotropy from 1H MAS NMR sideband patterns of surface OH groups

    NASA Astrophysics Data System (ADS)

    Fenzke, Dieter; Hunger, Michael; Pfeifer, Harry

    A procedure is described which allows a separate determination of the proton-aluminum distance and of the chemical-shift anisotropy for the bridging OH groups of crystalline molecular sieves from their 'H MAS NMR sideband patterns. For the bridging OH groups which point into the 6-rings of the framework (line "c"), the 1H- 27Al distance could be determined to be 0.237 ± 0.004 and 0.234 ± 0.004 nm for molecular sieves of type H-Y and SAPO-5, respectively. In contrast, for the bridging OH groups of the 12-rings (line "b"), the corresponding distances are equal and distinctly larger, 0.248 ± 0.004 nm. Within the limits of error, the values of the chemical-shift anisotropy are equal (about 19 ± 2 ppm) except for line b of SAPO-5, which exhibits a much smaller value of 14.5 ± 2 ppm.

  12. Proton 1H- and Phosphorus 31P-MR spectroscopy (MRS) in asymptomatic HIV-positive patients

    PubMed Central

    Schuettfort, Gundolf; Hattingen, Elke; Pilatus, Ulrich; Stephan, Christoph; Wolf, Timo; Goepel, Siri; Haberl, Annette; Blasel, Stella; Zanella, Freidhelm; Brodt, Hans-Reinhard; Bickel, Markus

    2014-01-01

    Introduction HIV infection is accompanied by a variety of neurological disorders. Depression of cell-mediated immunity is followed by the development of central nervous system opportunistic infections/tumours, and frequently by the occurrence of the AIDS dementia complex (ADC). However, the pathophysiology of the emergence of neuro-AIDS is still unknown. Despite the development of cognitive impairments, the early diagnosis, objectification and quantification of the existence and extent of this impairment during infection are difficult to recognize in each individual case. To support the early diagnosis of ADC, there is a need for additional, non-invasive diagnostic methods. In this study, it is of interest to answer the clinically relevant question of whether magnetic resonance spectroscopy can detect changes in the cerebral metabolism of asymptomatic HIV-positive patients and is possibly suitable for the early diagnosis and prevention of HIV encephalopathy. Methods A group of 13 asymptomatic, HIV-positive patients with combined antiretroviral therapy (cART) and 13 healthy controls were examined with 2D 1H-MRS and 3D 31P-MRS at 3T. The patients were treated with cART for at least 12 months. Changes in the absolute concentrations of phosphorylated metabolites (ATP), N-acetyl-aspartate, creatine, myo-Isonitol, glutamate/glutamine and choline-containing compounds were compared with that of control subjects. Results Asymptomatic HIV-positive patients had significantly lower N-acetyl-aspartate in the white matter in a frontal and parietal target region. The other evaluated metabolites in the 1H MRS showed no significant difference between the HIV-positive patients and healthy controls. The 31P-MRS detected significant elevated values regarding the choline-containing compounds PEth, GPE and PCho. Conclusions This spectroscopic study revealed a significantly lower N-acetyl-aspartate in the white matter in a frontal and parietal cerebral target region in asymptomatic, HIV

  13. Differential Regulation of ERK1/2 and mTORC1 Through T1R1/T1R3 in MIN6 Cells

    PubMed Central

    Wauson, Eric M.; Guerra, Marcy L.; Dyachok, Julia; McGlynn, Kathleen; Giles, Jennifer; Ross, Elliott M.

    2015-01-01

    The MAPKs ERK1/2 respond to nutrients and other insulin secretagogues in pancreatic β-cells and mediate nutrient-dependent insulin gene transcription. Nutrients also stimulate the mechanistic target of rapamycin complex 1 (mTORC1) to regulate protein synthesis. We showed previously that activation of both ERK1/2 and mTORC1 in the MIN6 pancreatic β-cell-derived line by extracellular amino acids (AAs) is at least in part mediated by the heterodimeric T1R1/T1R3, a G protein-coupled receptor. We show here that AAs differentially activate these two signaling pathways in MIN6 cells. Pretreatment with pertussis toxin did not prevent the activation of either ERK1/2 or mTORC1 by AAs, indicating that Gi is not central to either pathway. Although glucagon-like peptide 1, an agonist for a Gs-coupled receptor, activated ERK1/2 well and mTORC1 to a small extent, AAs had no effect on cytosolic cAMP accumulation. Ca2+ entry is required for ERK1/2 activation by AAs but is dispensable for AA activation of mTORC1. Pretreatment with UBO-QIC, a selective Gq inhibitor, reduced the activation of ERK1/2 but had little effect on the activation of mTORC1 by AAs, suggesting a differential requirement for Gq. Inhibition of G12/13 by the overexpression of the regulator of G protein signaling domain of p115 ρ-guanine nucleotide exchange factor had no effect on mTORC1 activation by AAs, suggesting that these G proteins are also not involved. We conclude that AAs regulate ERK1/2 and mTORC1 through distinct signaling pathways. PMID:26168033

  14. MR imaging and spectroscopy of the basal ganglia in chronic liver disease: correlation of T1-weighted contrast measurements with abnormalities in proton and phosphorus-31 MR spectra.

    PubMed

    Taylor-Robinson, S D; Sargentoni, J; Oatridge, A; Bryant, D J; Hajnal, J V; Marcus, C D; Seery, J P; Hodgson, H J; deSouza, N M

    1996-09-01

    The purpose of this study was to correlate the hyperintensity in the globus pallidus seen on T1-weighted magnetic resonance imaging (MRI) of the brain in chronic liver disease with changes in metabolite ratios measured from both proton and phosphorus-31 magnetic resonance spectroscopy (MRS) localised to the basal ganglia. T1-weighted spin echo (T1WSE) images were obtained in 21 patients with biopsy-proven cirrhosis (nine Child's grade A, eight Child's grade B and four Child's grade C). Four subjects showed no evidence of neuropsychiatric impairment on clinical, psychometric and electrophysiological testing, four showed evidence of subclinical hepatic encephalopathy and 13 had overt hepatic encephalopathy. Signal intensities of the globus pallidus and adjacent brain parenchyma were measured and contrast calculated, which correlated with the severity of the underlying liver disease, when graded according to the Pugh's score (p < 0.05). Proton MRS of the basal ganglia was performed in 12 patients and 14 healthy volunteers. Peak area ratios of choline (Cho), glutamine and glutamate (Glx) and N-acetylaspartate relative to creatine (Cr) were measured. Significant reductions in mean Cho/Cr and elevations in mean Glx/Cr ratios were observed in the patient population. Phosphorus-31 MRS of the basal ganglia was performed in the remaining nine patients and in 15 healthy volunteers. Peak area ratios of phosphomonoesters (PME), inorganic phosphate, phosphodiesters (PDE) and phosphocreatine relative to beta ATP (ATP) were then measured. Mean values of PME/ATP and PDE/ATP were significantly lower in the patient population. No correlation was found between the T1WSE MRI contrast measurements of the globus pallidus and the abnormalities in the metabolite ratios measured from either proton or phosphorus-31 MR spectra. Our results suggest that pallidal hyperintensity seen on T1WSE MR imaging of patients with chronic liver disease is not related to the functional abnormalities of the

  15. Tissue damage within normal appearing white matter in early multiple sclerosis: assessment by the ratio of T1- and T2-weighted MR image intensity.

    PubMed

    Beer, A; Biberacher, V; Schmidt, P; Righart, R; Buck, D; Berthele, A; Kirschke, J; Zimmer, C; Hemmer, B; Mühlau, M

    2016-08-01

    Histopathological and magnetic resonance imaging (MRI) studies have shown white matter (WM) damage in early stages of multiple sclerosis (MS) beyond the apparent T2-hyperintense lesions. These changes in normal appearing WM (NAWM) are important with regard to the clinical picture and prognosis. However, the detection of changes within NAWM has so far required special imaging techniques commonly not available in clinical routine and, hence, at large scale. The purpose of this study was to detect MS-related damage of NAWM by conventional MRI. As, within NAWM, the myelin content mainly drives the T1-weighted (T1w) signal, we scaled it by the T2w signal. We tested the hypothesis that the mean T1w/T2w ratio of NAWM is decreased in MS compared to healthy controls (HC) and that it correlates with clinical measures. We developed a pipeline to determine the individual mean values of this ratio within NAWM. We studied 244 patients in early disease stages of MS (mean age 37 ± 10 years, mean disease duration 3.1 ± 2.3, Expanded Disability Status Scale 1.3 ± 1), and 78 HC (mean age 31 ± 8 years). Compared to HC, the mean T1w/T2w ratio was lowered in the patient group (P < 0.001). The difference remained significant after restricting the analysis to patients with a disease duration of 5 years or less and without disease modifying drugs. Our measures also correlated with clinical scores. We believe that the mean T1w/T2w ratio is a promising candidate to assess MS-related tissue damage within NAWM at large scale. PMID:27178000

  16. Glucose-Sensing Receptor T1R3: A New Signaling Receptor Activated by Glucose in Pancreatic β-Cells.

    PubMed

    Kojima, Itaru; Nakagawa, Yuko; Hamano, Kunihisa; Medina, Johan; Li, Longfei; Nagasawa, Masahiro

    2015-01-01

    Subunits of the sweet taste receptors T1R2 and T1R3 are expressed in pancreatic β-cells. Compared with T1R3, mRNA expression of T1R2 is considerably lower. At the protein level, expression of T1R2 is undetectable in β-cells. Accordingly, a major component of the sweet taste-sensing receptor in β-cells may be a homodimer of T1R3 rather than a heterodimer of T1R2/T1R3. Inhibition of this receptor by gurmarin or deletion of the T1R3 gene attenuates glucose-induced insulin secretion from β-cells. Hence the T1R3 homodimer functions as a glucose-sensing receptor (GSR) in pancreatic β-cells. When GSR is activated by the T1R3 agonist sucralose, elevation of intracellular ATP concentration ([ATP]i) is observed. Sucralose increases [ATP]i even in the absence of ambient glucose, indicating that sucralose increases [ATP]i not simply by activating glucokinase, a rate-limiting enzyme in the glycolytic pathway. In addition, sucralose augments elevation of [ATP]i induced by methylsuccinate, suggesting that sucralose activates mitochondrial metabolism. Nonmetabolizable 3-O-methylglucose also increases [ATP]i and knockdown of T1R3 attenuates elevation of [ATP]i induced by high concentration of glucose. Collectively, these results indicate that the T1R3 homodimer functions as a GSR; this receptor is involved in glucose-induced insulin secretion by activating glucose metabolism probably in mitochondria. PMID:25947913

  17. TrkB.T1 Contributes to Neuropathic Pain after Spinal Cord Injury through Regulation of Cell Cycle Pathways

    PubMed Central

    Wu, Junfang; Renn, Cynthia L.

    2013-01-01

    Spinal cord injury (SCI) frequently causes severe, persistent central neuropathic pain that responds poorly to conventional pain treatments. Brain-derived neurotrophic factor (BDNF) signaling appears to contribute to central sensitization and nocifensive behaviors in certain animal models of chronic pain through effects mediated in part by the alternatively spliced truncated isoform of the BDNF receptor tropomyosin-related kinase B.T1 (trkB.T1). Mechanisms linking trkB.T1 to SCI-induced chronic central pain are unknown. Here, we examined the role of trkB.T1 in central neuropathic pain after spinal cord contusion. Genetic deletion of trkB.T1 in mice significantly reduced post-SCI mechanical hyperesthesia, locomotor dysfunction, lesion volumes, and white matter loss. Whole genome analysis, confirmed at the protein level, revealed that cell cycle genes were upregulated in trkB.T1+/+ but not trkB.T1−/− spinal cord after SCI. TGFβ-induced reactive astrocytes from WT mice showed increased cell cycle protein expression that was significantly reduced in astrocytes from trkB.T1−/− mice that express neither full-length trkB nor trkB.T1. Administration of CR8, which selectively inhibits cyclin-dependent kinases, reduced hyperesthesia, locomotor deficits, and dorsal horn (SDH) glial changes after SCI, similar to trkB.T1 deletion, without altering trkB.T1 protein expression. In trkB.T1−/− mice, CR8 had no effect. These data indicate that trkB.T1 contributes to the pathobiology of SCI and SCI pain through modulation of cell cycle pathways and suggest new therapeutic targets. PMID:23884949

  18. ESR lineshape and 1H spin-lattice relaxation dispersion in propylene glycol solutions of nitroxide radicals - Joint analysis

    NASA Astrophysics Data System (ADS)

    Kruk, D.; Hoffmann, S. K.; Goslar, J.; Lijewski, S.; Kubica-Misztal, A.; Korpała, A.; Oglodek, I.; Kowalewski, J.; Rössler, E. A.; Moscicki, J.

    2013-12-01

    Electron Spin Resonance (ESR) spectroscopy and Nuclear Magnetic Relaxation Dispersion (NMRD) experiments are reported for propylene glycol solutions of the nitroxide radical: 4-oxo-TEMPO-d16 containing 15N and 14N isotopes. The NMRD experiments refer to 1H spin-lattice relaxation measurements in a broad frequency range (10 kHz-20 MHz). A joint analysis of the ESR and NMRD data is performed. The ESR lineshapes give access to the nitrogen hyperfine tensor components and the rotational correlation time of the paramagnetic molecule. The NMRD data are interpreted in terms of the theory of paramagnetic relaxation enhancement in solutions of nitroxide radicals, recently presented by Kruk et al. [J. Chem. Phys. 138, 124506 (2013)]. The theory includes the effect of the electron spin relaxation on the 1H relaxation of the solvent. The 1H relaxation is caused by dipole-dipole interactions between the electron spin of the radical and the proton spins of the solvent molecules. These interactions are modulated by three dynamic processes: relative translational dynamics of the involved molecules, molecular rotation, and electron spin relaxation. The sensitivity to rotation originates from the non-central positions of the interacting spin in the molecules. The electronic relaxation is assumed to stem from the electron spin-nitrogen spin hyperfine coupling, modulated by rotation of the radical molecule. For the interpretation of the NMRD data, we use the nitrogen hyperfine coupling tensor obtained from ESR and fit the other relevant parameters. The consistency of the unified analysis of ESR and NMRD, evaluated by the agreement between the rotational correlation times obtained from ESR and NMRD, respectively, and the agreement of the translation diffusion coefficients with literature values obtained for pure propylene glycol, is demonstrated to be satisfactory.

  19. Spectroscopic (FT-IR, FT-Raman, UV, 1H and 13C NMR) profiling and theoretical calculations of (2E)-2-[3-(1H-imidazol-1-yl)-1-phenylpropylidene]hydrazinecarboxamide: An anticonvulsant agent

    NASA Astrophysics Data System (ADS)

    Haress, Nadia G.; Govindarajan, Munusamy; AL-Wabli, Reem I.; Almutairi, Maha S.; Al-Alshaikh, Monirah A.; Al-Saadi, Abdulaziz A.; Attia, Mohamed I.

    2016-08-01

    Vibrational characteristics of the anticonvulsant agent, (2E)-2-[3-(1H-imidazol-1-yl)-1-phenylpropylidene]hydrazinecarboxamide ((2E)-IPHC) have been investigated. The computational data are obtained by adopting ab initio Hartree-Fock (HF) and DFT/B3LYP/6-31 + G(d,p) methods. The most stable conformer is identified by a potential energy scan. The optimized geometrical parameters indicated that the overall symmetry of the most stable conformer is CS. Atoms in molecules (AIM) analysis is contained out and the chemical bondings between the atoms are as characterized. Mulliken atomic charges and simulated thermo-molecular (heat capacity and enthalpy) characteristics of the (2E)-IPHC molecule also have been analyzed. The magnitude of the molecular electrostatic potential (MEP) of oxygen, hydrogen, and nitrogen atoms as well as phenyl and imidazole rings in the title molecule were investigated along with their contribution to the biological activity. The energy gap between HOMO and LUMO orbitals has been found to be 5.1334 eV in the gaseous phase. Excitation energies, oscillator strength and wavelengths were computed by the time-dependent density function theory (TD-DFT) approach. Predicted wavenumbers have been assigned and they are consistent with the experimental values. The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of the (2E)-IPHC molecule were computed by the gauge independent atomic orbital (GIAO) method and were compared with the experimental results.

  20. Design, synthesis and biological evaluation of N-((1-benzyl-1H-1,2,3-triazol-4-yl)methyl)-1,3-diphenyl-1H-pyrazole-4-carboxamides as CDK1/Cdc2 inhibitors.

    PubMed

    Ganga Reddy, V; Srinivasa Reddy, T; Lakshma Nayak, V; Prasad, Budaganaboyina; Reddy, Adiyala Praveen; Ravikumar, A; Taj, Shaik; Kamal, Ahmed

    2016-10-21

    A series of new (N-((1-benzyl-1H-1,2,3-triazol-4-yl)methyl)-1,3-diphenyl-1H-pyrazole-4-carboxamide derivatives (8-35) were designed, synthesized and evaluated as CDK1/Cdc2 inhibitors. Biological evaluation assays indicated that compounds 16 and 27 showed the most potent growth inhibitory activity against human cancer cell lines (MIAPaCa-2, MCF-7 and HeLa) with GI50 values ranging from 0.13 to 0.7 μM, compared with the positive control nocodazole (0.81-0.95 μM). Flow cytometric analysis revealed that these compounds induce cell cycle arrest in the G2/M phase and Western blot analysis suggested that compound treatment resulted in reduction of CDK1 expression levels in MCF-7 cell line. Moreover, the apoptosis inducing effect of the compounds was studied using Hoechst staining, Rhodamine 123 staining (MMP), carboxy-DCFDA staining (ROS), Annexin V-FITC assay. Based on these studies, two compounds 16 and 27 have been identified as promising new molecules that have the potential to be developed as leads. PMID:27344493

  1. The structure and properties of 5,6-dinitro-1H-benzotriazole

    NASA Astrophysics Data System (ADS)

    Santa María, Dolores; Claramunt, Rosa M.; Torralba, M. Carmen; Torres, M. Rosario; Alkorta, Ibon; Elguero, José

    2016-06-01

    5,6-Dinitro-1H-benzotri