bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rapid and simultaneous measurement of phosphorus metabolite pool size ratio and reaction kinetics of enzymes in vivo
Authors: Kim Sang‐Young , Chen Wei , Ongur Dost , Du Fei 
Published: May 2017

PurposeThe metabolites phosphocreatine (PCr), adenosine triphosphate (ATP), and in‐organic phosphate (Pi) are biochemically coupled. Their pool sizes, assessed by their magnetization ratios, have been extensively studied and reflect bioenergetics status in vivo. However, most such studies have ignored chemical exchange and T1 relaxation effects. In this work, we aimed to extend the
method to simultaneously quantify the reaction rate constants as well as phosphorus metabolite pool size ratios under partially relaxed conditions.Materials and MethodsModified Bloch‐McConnell equations were used to simulate the effects of chemical exchanges on T1 relaxation times and magnetization ratios among PCr, γ‐ATP, and Pi. The
method with iteration approach was used to measure both reaction constants and metabolite pool size ratios. To validate our method, in vivo data from rat brains (N = 8) at 9.4 Tesla were acquired under two conditions, i.e., approximately full relaxation (TR = 9 s) and partial relaxation (TR = 3 s). We compared metabolite pool size ratios and reaction constants before and after correcting the chemical exchange and T1 relaxation effects.ResultsThere were significant errors in underestimation of PCr/γATP by 12 % (P = 0.03) and overestimation of ATP/Pi ratios by 14 % (P = 0.04) when not considering chemical exchange effects. These errors were minimized using our iteration approach, resulting in no significant differences (PCr/γATP, P = 0.47; ATP/Pi, P = 0.81) in metabolite pool size ratios and reaction constants between the two measurements (i.e., short versus long TR conditions).ConclusionOur method can facilitate broad biomedical applications of 31P magnetization saturation transfer spectroscopy, requiring high temporal and/or spatial resolution for assessment of altered bioenergetics.Level of Evidence: 2Technical Efficacy: Stage 1J. Magn. Reson. Imaging 2018;47:210–221.
When should we use contrast material in cardiac MRI?
Authors: Paiman Elisabeth H.M. , Lamb Hildo J. 
Published: May 2017

At present, most of the cardiac magnetic resonance imaging (MRI) examinations rely on contrast‐enhanced protocols, but noncontrast alternatives are emerging. Late gadolinium enhancement (LGE) imaging for the detection of myocardial scar can be considered the main cause for the embedding of cardiac MRI into the clinical routine. The novel noncontrast technique of native T1 mapping shows promise for tissue characterization in ischemic and nonischemic cardiomyopathy and may provide additional information over conventional LGE imaging. Technical issues, including measurements variability, still need to be resolved to facilitate a wide clinical application. Ischemia detection can be performed with contrast‐based stress perfusion and contrast‐free stress wall motion imaging. For coronary magnetic resonance angiography (MRA), protocols with and without contrast material have been developed. Research on coronary atherosclerotic plaque characterization has introduced new applications of contrast material. For MRA of the aorta, which traditionally relied on contrast administration, several noncontrast protocols have become available. This review provides an overview of when to use contrast material in cardiac and cardiac‐related vascular MRI, summarizes the major imaging building blocks, and describes the diagnostic value of the available contrast‐enhanced and noncontrast techniques. Contrast material in cardiac MRI should be used for LGE imaging for tissue characterization in ischemic or nonischemic cardiomyopathy and may be used for stress perfusion imaging for the detection of ischemia. In cardiac‐related vascular MRI, use of contrast material should be avoided, unless high‐quality angiography is required that cannot be obtained with noncontrast protocols.Level of Evidence: 5Technical Efficacy: Stage 3J. Magn. Reson. Imaging 2017;46:1551–1572.
Pancreatic neuroendocrine tumor: Correlations between MRI features, tumor biology, and clinical outcome after surgery
Authors: Canellas Rodrigo , Lo Grace , Bhowmik Sreejita , Ferrone Cristina , Sahani Dushyant 
Published: May 2017

PurposeTo assess which magnetic resonance imaging (MRI) features are associated with pNETs (pancreatic neuroendocrine tumors) grade based on the WHO classification, as well as identify MRI features related to disease progression after surgery.Materials and MethodsIn this Institutional Review Board (IRB)‐approved study, 1.5T and 3.0T MRI scans of 80 patients with surgically verified pNETs were assessed. The images were evaluated for tumor location; size; pattern; predominant signal intensity on precontrast T1‐ and T2‐weighted images, as well as on postcontrast arterial and portal venous phase T1‐weighted sequences; presence of pancreatic duct dilatation; pancreatic atrophy; restricted diffusion; vascular involvement by the tumor; extrapancreatic tumor spread; and synchronous liver metastases. Tumors were graded based on the WHO classification and patients were followed‐up with computed tomography (CT) or MRI after surgical resection. Data were analyzed with Student's t and chi‐square tests, logistic regression, and Kaplan–Meier curves.ResultsThe MRI features that were associated with aggressive tumors were: size >2.0 cm (odds ratio [OR] = 4.8, P = 0.002), “T2 nonbright lesions” on T2‐weighted images (OR = 4.6, P = 0.008), presence of pancreatic ductal dilatation (OR = 4.9, P = 0.024), and restricted diffusion within the lesion (OR = 4.9, P = 0.013). Differences in progression‐free survival distribution were found for patients whose pNETs were associated with the following MRI features: size >2.0 cm (χ2 (1) = 6.0, P = 0.014), “nonbright lesions” on T2‐weighted images (χ2 (1) = 6.8, P = 0.009), and presence of pancreatic duct dilatation (χ2 (1) = 10.9, P = 0.001).ConclusionMRI features can be used to assess pNETs aggressiveness and identify patients at risk for early disease progression after surgical resection.Level of Evidence: 3Technical Efficacy: Stage 3J. Magn. Reson. Imaging 2018;47:425–432.
Fragmentation characteristics of hydroxycinnamic acids in ESI‐MSn by density functional theory
Authors: Yin Zhi‐Hui , Sun Chang‐Hai , Fang Hong‐Zhuang 
Published: May 2017

This work aims to analyze the electrospray ionization multistage mass spectrometry (ESI‐MSn) fragmentation characteristics of hydroxycinnamic acids (HCAs) in negative ion mode. The geometric parameters, energies, natural bond orbitals and frontier orbitals of fragments were calculated by density functional theory (DFT) to investigate mass spectral fragmentation mechanisms. The results showed that proton transfer always occurred during fragmentation of HCAs; their quasi‐molecular ions ([M − H]−) existed in more than one form and were mainly with the lowest energy. The fragmentation characteristics included the followings: (1) according to the different substitution position of phenolic hydroxyl group, the ring contraction reaction by CO elimination from benzene was in an increasingly difficult order: m‐phenolic hydroxyl > p‐phenolic hydroxyl > o‐phenolic hydroxyl; and (2) ortho effect always occurred in o‐dihydroxycinnamic acids (o‐diHCAs), i.e. one phenolic hydroxyl group offered H+, which combined with the other one to lose H2O. In addition, there was a nucleophilic reaction during ring contraction in diHCAs that oxygen atom attacked the carbon atom binding with the other phenolic hydroxyl to lose CO2. The fragmentation characteristics and mechanism of HCAs could be used for analysis and identification of such compounds quickly and effectively, and as reference for structural analogues by ESI‐MS. Copyright © 2017 John Wiley & Sons, Ltd.
Seasonal nitrogen uptake and regeneration in the western coastal Arctic
Authors: Baer Steven E. , Sipler Rachel E. , Roberts Quinn N. , Yager Patricia L. , Frischer Marc E. , Bronk Deborah A. 
Published: May 2017

AbstractHere, we present the first study to investigate the seasonal importance of amino acid‐nitrogen (N) to Arctic near shore microbial communities. We measured primary productivity and the uptake of ammonium, nitrate, urea, and amino acids in two size fractions (> 3 μm and approximately 0.7–3 μm), as well as ammonium regeneration and nitrification using 15N and 13C tracer approaches in the near‐shore waters of the Chukchi Sea, during January, April, and August for two consecutive years. At discrete depths, nitrate comprised 46–78% of the total dissolved N pool during January and April but only 2–6% during August. Dissolved organic N (DON) concentrations increased between January and August though the carbon (C) : N (mol : mol) of the DON pool declined. Of the substrates tested, amino acids supported the bulk of both N and C nutrition in both size fractions during January and April (ice‐covered). Urea generally had the lowest uptake rate under ice‐covered conditions; uptake of urea‐C was only detectable in August. Though previous Arctic studies focused largely on nitrate, we found nitrate uptake was generally lower than other substrates tested. The sharp decline in nitrate concentration between April and August, however, indicates a drawdown of nitrate during that period. Rates of ammonium uptake were highest in August, when it was the dominant N substrate used. During all sample periods, rates of ammonium regeneration were sufficient to supply ammonium demand. Rates of nitrification varied between sample periods, however, with much higher rates seen in January and April.
A synoptic survey of microbial respiration, organic matter decomposition, and carbon efflux in U.S. streams and rivers
Authors: Hill Brian H. , Elonen Colleen M. , Herlihy Alan T. , Jicha Terri M. , Mitchell Richard M. 
Published: May 2017

AbstractWe analyzed ecoenzyme activities related to organic matter processing in 1879 streams and rivers across the continental U.S. as part of the USEPA's National Rivers and Streams Assessment. Ecoenzymatic stoichiometry was used to construct models for carbon use efficiency (CUE) and decomposition (−k). Microbial respiration (Rm) was estimated from sediment organic carbon stocks, CUE, and −k. The streams and rivers were classified by size (headwaters: 1st‐order; streams: 2nd–3rd order; small rivers: 4th–5th order; big rivers 6th–7th order; and great rivers ≥ 8th order) and condition class (least, intermediate, and most disturbed), and grouped into nine ecoregions. There were ecoregion, stream size, and condition class effects for CUE, −k, and Rm, with Rm increasing from eastern ecoregions through the plains to the western ecoregions. CUE, −k, and Rm decreased with increasing streams size and increased with increasing disturbance. Rm, CUE, and −k were correlated with water and sediment chemistry; CUE and −k were also correlated with stream bed fine sediments; and CUE was further correlated with catchment land cover. Rm was extrapolated to ecoregional and national scales, and the results suggest that microbial assemblages account for 12% of the total CO2 outgassing, and nearly 50% of the aquatic metabolism C losses, from U.S. streams and rivers. Cumulative respiratory C losses increased from headwaters to small streams, then decreased with increasing stream size. This U‐shaped respiration curve was not evident when streams were viewed by disturbance classes, suggesting that anthropogenic disturbances mask the expected organic matter processing signature of the river continuum.
Flexible Diazide Based Sulfonated Polytriazoles and Their Proton Exchange Membrane Properties
Authors: Saha Sayantani , Banerjee Susanta , Komber Hartmut , Voit Brigitte 
Published: May 2017

The preparation, characterization, and property evaluation of a series of new semifluorinated polytriazoles (PTEHSH‐XX) with various degrees of sulfonation is described. The polymers are synthesized by the click polymerization reaction of a mixture of a new diazide monomer, 1,4‐bis‐[{2′‐trifluromethyl 4′‐(4″‐azidophenyl)phenoxy}]phenyl, and a sulfonated monomer, 4,4′‐diazido‐2,2′‐stilbenedisulfonic acid disodium salt, with an equimolar amount of a dialkyne monomer, 1,3‐diethynylbenzene. The polytriazoles are characterized by Fourier transform infrared spectroscopy (FTIR) and NMR spectroscopic techniques. The polytriazoles show good solubility in selective organic solvents and film forming ability. The films prepared from these polymers show high thermal and chemical stability, low water uptake, high dimensional stability, and excellent mechanical properties. The transmission electron microscopy images of these polymers exhibit a uniformly phase separated morphology. The polymers show very high proton conductivity and the values are within the range of 27–118 mS cm−1 at 30 °C, 53–225 mS cm−1 at 80 °C, and 58–235 mS cm−1 at 90 °C in hydrated condition.
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Different renal phenotypes in related adult males with Fabry disease with the same classic genotype
Authors: Mignani Renzo , Moschella Mariarita , Cenacchi Giovanna , Donati Ilaria , Flachi Marta , Grimaldi Daniela , Cerretani Davide , Giovanni Paola De , Montevecchi Marcello , Rigotti Angelo , Ravasio Alessandro 
Published: May 2017

AbstractBackgroundFabry disease related patients with classical mutation usually exhibit similar severe phenotype especially concerning renal manifestation.MethodsA dry blood spot screening (DBS) and the DNA analysis has been performed in a 48‐year‐old man (Patient 1) because of paresthesia.ResultsThe DBS revealed absent leukocyte α‐Gal A enzyme activity while DNA analysis identified the I354K mutation. Serum creatinine and e‐GFR were in normal range and also albuminuria and proteinuria were absent. The brain MRI showed ischemic lesions and a diffuse focus of gliosis in the white matter, while the echocardiogram showed a left ventricular hypertrophy. The renal biopsy performed in the case index showed a massive deposition of zebra bodies. By a familiar investigation, it was recognized that his brother (Patient 2) died 2 years before from sudden death syndrome at the age of 49. He had suffered sporadic and undiagnosed pain at the extremities, a prior cataract, bilateral neurosensorial hearing loss and left ventricular hypertrophy on Echocardiogram. His previous laboratory examinations revealed a normal serum creatinine and the absence of proteinuria. Pedigree analysis of the brothers revealed a high disease burden among family members, with an affected cousin (Patient 3) who progressed early to end‐stage renal disease (ESRD) that required renal transplantation.ConclusionsHere we describe the clinical history of three adult male members of the same family with the same genotype who manifested different presentation and progression of the disease, particularly concerning the renal involvement.
Mathematical Modeling of Nylon 6/6,6 Copolymerization: Beneficial Influence of Comonomers on Degree of Polymerization in Batch Reactor
Authors: Liu Fei F. , Hurley James M. , Khare Neeraj P. , McAuley Kim B. 
Published: May 2017

AbstractA model is developed for hydrolytic copolymerization of caprolactam with hexamethylene diamine (HMD) and adipic acid (ADA) in a batch reactor to produce nylon 6/6,6 copolymer. The reaction mechanism includes hydrolysis of caprolactam and cyclic dimer, polycondensation, polyaddition, transamidation, and ring formation via end biting and back biting. The catalyzing effect of carboxyl groups is accounted for using kinetic parameters from the literature. Model predictions are compared with low‐temperature literature data before simulating reactor conditions of industrial interest. The model predicts a higher degree of polymerization (DP) for nylon 6/6,6 copolymer compared to nylon 6 and 6,6 homopolymers produced using the same reactor conditions. Dynamic changes in concentrations of water, caprolactam, HMD, ADA, and end groups are tracked and used to explain the positive influence of comonomers on reaction rates and DP. Insights gained from this model will form a useful basis to build future models of continuous industrial reactors.
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Human Neural Stem Cell Biodistribution and Predicted Tumor Coverage by a Diffusible Therapeutic in a Mouse Glioma Model
Authors: Barish Michael E. , Herrmann Kelsey , Tang Yang , Argalian Herculian Siranush , Metz Marianne , Aramburo Soraya , Tirughana Revathiswari , Gutova Margarita , Annala Alexander , Moats Rex A. , Goldstein Leanne , Rockne Russell C. , Gutierrez Jennifer , Brown Christine E. , Ghoda Lucy , Aboody Karen S. 
Published: May 2017

Abstract
Engineered neural stem cells (NSCs) intrinsically migrating to brain tumors offer a promising mechanism for local therapeutic delivery. However, difficulties in quantitative assessments of NSC migration and in estimates of tumor coverage by diffusible therapeutics have impeded development and refinement of NSC-based therapies. To address this need, we developed techniques by which conventional serial-sectioned formalin-fixed paraffin-embedded (FFPE) brains can be analyzed in their entirety across multiple test animals. We considered a conventional human glioblastoma model: U251 glioma cells orthotopically engrafted in immunodeficient mice receiving intracerebral (i.c.) or intravenous (i.v.) administrations of NSCs expressing a diffusible enzyme to locally catalyze chemotherapeutic formation. NSC migration to tumor sites was dose-dependent, reaching 50%–60% of total administered NSCs for the i.c route and 1.5% for the i.v. route. Curiously, the most efficient NSC homing was seen with smaller NSC doses, implying existence of rate-limiting process active during administration and/or migration. Predicted tumor exposure to a diffusing therapeutic (assuming a 50 µm radius of action) could reach greater than 50% of the entire tumor volume for i.c. and 25% for i.v. administration. Within individual sections, coverage of tumor area could be as high as 100% for i.c. and 70% for i.v. routes. Greater estimated therapeutic coverage was observed for larger tumors and for larger tumor regions in individual sections. Overall, we have demonstrated a framework within which investigators may rationally evaluate NSC migration to, and integration into, brain tumors, and therefore enhance understanding of mechanisms that both promote and limit this therapeutic modality.
Decolonization in a Digital Age: Cryptocurrencies and Indigenous Self-Determination in Canada
Authors: Alcantara Christopher , Dick Caroline 
Published: May 2017

Abstract
Indigenous scholars and leaders have long been interested in reducing the role of the Canadian state in their political, economic, and social lives. This paper explores the extent to which digital currencies, such as Bitcoin or MazaCoin, might be used to facilitate Indigenous self-determination, political autonomy, and economic prosperity. Based on our review of the literature, we argue that cryptocurrencies demonstrate some potential for advancing these goals but that there are a number of potential roadblocks as well. Future research should investigate how Indigenous communities might use digital currencies and other related technologies to further their political, economic, and social goals.
Automating long-term glacier dynamics monitoring using single-station seismological observations and fuzzy logic classification: a case study from Spitsbergen
Authors: GAJEK W. , TROJANOWSKI J. , MALINOWSKI M. 
Published: May 2017

ABSTRACTRetreating glaciers are a consequence of a warming climate. Thus, numerous monitoring campaigns are being carried out to increase understanding of this on-going process. One phenomenon related to dynamic glacial changes is glacier-induced seismicity; however, weak seismic events are difficult to record due to the sparse seismological network in arctic areas. We have developed an automatic procedure capable of detecting glacier-induced seismic events using records from a single permanent seismological station. To distinguish between glacial and non-glacial signals, we developed a fuzzy logic algorithm based on the signal frequency and energy flow analysis. We studied the long-term changes in glacier-induced seismicity in Hornsund (southern Spitsbergen) and in Kongsfjorden (western Spitsbergen). We found that the number of detected glacial-origin events in the Hornsund dataset over the years 2013-14 has doubled. In the Kongsfjorden dataset, we observed a steady increase in the number of glacier-induced events with each year. We also observed that the seasonal event distribution correlates best with 1 month lagged temperatures, and that extreme rain events can intensify seismic emissions. Our study demonstrates the possibility of using long-term seismological observations from a single permanent station to automatically monitor the dynamic activity of nearby glaciers and retrieve its characteristic features.
Alcohol consumption pattern and risk of Barrett’s oesophagus and erosive oesophagitis: an Italian case–control study
Authors: Filiberti Rosa A. , Fontana Vincenzo , De Ceglie Antonella , Blanchi Sabrina , Grossi Enzo , Della Casa Domenico , Lacchin Teresa , De Matthaeis Marina , Ignomirelli Orazio , Cappiello Roberta , Rosa Alessandra , Foti Monica , Laterza Francesco , D’Onofrio Vittorio , Iaquinto Gaetano , Conio Massimo 
Published: May 2017

AbstractKnowledge about the association between alcohol and Barrett’s oesophagus and reflux oesophagitis is conflicting. In this case–control study we evaluated the role of specific alcoholic beverages (red and white wine, beer and liquors) in 339 Barrett’s oesophagus and 462 oesophagitis patients compared with 619 endoscopic controls with other disorders, recruited in twelve Italian endoscopic units. Data on alcohol and other individual characteristics were obtained from structured questionnaires. No clear, monotonic significant dose–response relationship was pointed out for red wine. However, a generalised U-shaped trend of Barrett’s oesophagus/oesophagitis risk due to red wine consumption particularly among current drinkers was found. Similar results were also found for white wine. Liquor/spirit consumption seemed to bring about a 1·14–2·30 risk excess, although statistically non-significant, for current Barrett’s oesophagus/oesophagitis drinkers. Statistically significant decreasing dose–response relationships were found in Barrett’s oesophagus for frequency and duration of beer consumption. Similar, but less clear downward tendencies were also found for oesophagitis patients. In conclusion, although often not statistically significant, our data suggested a reduced risk of Barrett’s oesophagus and oesophagitis with a low/moderate intake of wine and beer consumption. A non-significant increased risk of Barrett’s oesophagus/oesophagitis was observed with a higher intake of any type of heavy alcohol consumption, but no conclusion can be drawn owing to the high number of non-spirit drinkers and to the small number of drinkers at higher alcohol intake levels.
Implications of Genetically Modified Crops and Intellectual Property Rights on Agriculture in Developing Countries
Authors: Olusegun Olaitan Oluwaseyi , Olubiyi Ifeoluwa Ayokunle 
Published: May 2017

AbstractFood is essential for human survival. When the right quantity and quality is taken, it ensures growth and an adequate supply of nutrition to the body, which results in basic effectiveness in all spheres of life. Genetically modified crops have the potential to alleviate hunger and provide more food, especially in developing countries that have high levels of hunger, malnutrition and poverty. Although the debates on genetically modified crops generally focus on intellectual property, other issues include health and environmental concerns. This article examines these issues with the aim of providing holistic knowledge of the subject matter, which is important for stakeholders, particularly in developing countries, in deciding to protect plant variety rights. The article concludes that it is essential for developing countries to consider food security issues in fulfilling their obligations under the TRIPS Agreement.