bluuebunny/crossref_metadata_2025_split huggingface dataset:
Versatile Donor‐Acceptor Cyclopropenes in Metal Carbene Transformations
Authors: Deng Yongming , Doyle Michael P. 
Published: January 2016

AbstractSelect transition metal compounds catalyze metal vinylcarbene formation from cyclopropenes, and their documented reactions include both intermolecular and intramolecular C−H insertion and cyclopropanation, as well as [3+3]‐cycloaddition. Although known to undergo carbene‐like transformations for decades, the uses of cyclopropenes as reactive alternatives to diazo compounds under mild conditions has been limited. However, recently developed donor‐acceptor cyclopropenes that are conveniently accessed from enoldiazoacetates and enoldiazoacetamides are effective metallo‐vinylcarbene precursors. They provide entry to highly stereoselective metal carbene transformations under reaction conditions that are milder than those required for dinitrogen extrusion from diazo compounds.
Becoming “Eligible to Matter”
Authors: Learned Julie E. 
Published: January 2016

AbstractThe practice of labeling readers persists in schools even though deficit labels can undermine literacy learning. To understand the literacy experiences of struggling readers, the author conducted a yearlong study in which she shadowed ninth graders across content area classes. This article examines times when youths appeared disengaged because they were experiencing high levels of stress due to, for example, homelessness or hunger. How teachers together with youths interpreted stress powerfully contributed to the construction of youths as struggling or capable readers and learners. When teachers saw stress as low motivation or work avoidance, it exacerbated deficit positioning. However, when teachers sought to understand the root causes of stress, teachers and youths jointly addressed obstacles in ways that bolstered youths' well‐being and literacy. Findings have implications for disrupting deficit notions about reading struggle and building positive student–teacher relationships through which students can grow as readers and young people.
T2 mapping at 7T MRI can quantitatively assess intramyocardial hemorrhage in rats with acute reperfused myocardial infarction in vivo
Authors: Chen Wei , Zhang Bing , Xia Rui , Zhang Ruzhi , Xu Ziqian , Chen Yushu , Wang Chunhua , Wang Lei , Zheng Jie , Gao Fabao 
Published: January 2016

PurposeTo investigate T2 mapping at 7T magnetic resonance imaging (MRI) for the detection and quantification of reperfused intramyocardial hemorrhage (IMH) in a rat model.Materials and MethodsMyocardial infarction (MI) was induced in 25 female rats. Rats were scanned at a 7T MRI 48 hours after reperfusion, using T2 mapping and late gadolinium enhancement imaging. Gross sections of the left ventricular myocardium and corresponding hematoxylin and eosin staining were assessed for IMH. T2 mapping images were matched with the gross sections. The IMH volume, expressed as a percentage of the left ventricular myocardial volume, of each heart determined by T2 mapping was compared with that calculated by pathological gross examination.ResultsSix rats died. In all, 97 gross sections of the left ventricular myocardium from the 19 rats were matched with T2 mapping images. IMH occurred pathologically in 68 gross sections, which was detected as hypointense cores by T2 mapping in 63 images (93% sensitivity). Three T2 mapping images with hypointense cores showed no hemorrhage on pathological sections (90% specificity). The positive and negative predictive values of hemorrhage on T2 mapping were 95% and 84%, respectively. In terms of the IMH volume, there was no significant difference between T2 mapping and pathological gross measurements (4.8 ± 2.4% vs. 5.3 ± 3.2%; P = 0.11).ConclusionT2 mapping at 7T MRI can reliably detect and quantify IMH in rats in vivo. This may be useful as a noninvasive quantitative approach to investigating the mechanisms and evolution of MI and reperfusion injury. J. Magn. Reson. Imaging 2016;44:194–203.
Quadriceps function relates to muscle size following ACL reconstruction
Authors: Kuenze Christopher M. , Blemker Silvia S. , Hart Joseph M. 
Published: January 2016

ABSTRACTIt remains unclear what role reduced volume and cross‐section area (CSA) of individual quadriceps muscles may play in persistent quadriceps weakness and more global dysfunction following ACL reconstruction (ACLR). The purpose of this investigation was to establish the relationship between cross‐sectional area of the quadriceps muscle group and measures of knee related and quadriceps function following ACLR. Thirty participants with a history of primary, unilateral ACLR experiencing persistent quadriceps activation failure participated in this cohort study. Clinical factors including International Knee Documentation Committee (IKDC) score, normalized knee extension MVIC torque (Nm/kg) and quadriceps central activation ratio (CAR, %) were assessed in addition to CSA. Quadriceps CSA was measured via magnetic resonance imaging (MRI; Siemens Avanto 1.5T). Quadriceps CSA (cm2) and quadriceps volume (cm3) as well as individual muscle estimates were identified within a 10 cm mid‐thigh capture area. Pearson's product‐moment correlation coefficients (r) established relationships between CSA and all other variables. Stepwise linear regression established which CSA factors were able to successfully predict clinical factors. Knee extension MVIC torque was strongly correlated with Vastus Intermedius (VI; r =  0.857, p < 0.001) CSA as well as partial VI (r = 0.849, p < 0.001) and quadriceps (r = 0.830, p < 0.001) volume. Partial VI (r = 0.365, p = 0.047) volume was weakly correlated with IKDC score. Knee extension MVIC torque was strongly predicted using VI CSA alone (R2 = 0.725) or in combination with Vastus Medialis CSA (VM; R2 = 0.756). Statement of Clinical Significance: Atrophy of the VI and VM muscles negatively impacts knee extension strength following ACLR. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1656–1662, 2016.
Proximate and fatty acid composition of zebra (Equus quagga burchellii) muscle and subcutaneous fat
Authors: Hoffman Louwrens C , Geldenhuys Greta , Cawthorn Donna‐Mareè 
Published: January 2016

AbstractBACKGROUNDThe meat from African game species is healthy, naturally produced and increasingly popular with consumers. Among these species, zebra (Equus quagga burchellii) are growing in number in South Africa, with the meat from surplus animals holding potential to contribute to food security and economic stability. Despite being consumed locally and globally, little information exists on the composition of zebra meat. This study aimed to determine the proximate composition of zebra meat as well as the fatty acid composition of the intramuscular (IMF) and subcutaneous (SCF) fat.RESULTSZebra longissimus lumborum muscle was shown to have a high mean protein content (22.29 g per 100 g) and low mean fat content (1.47 g per 100 g). High proportions of polyunsaturated fatty acids (PUFAs) were found in the IMF (41.15%) and SCF (37.71%), mainly comprising α‐linolenic (C18:3n‐3) and linoleic (C18:2n‐6) acids. Furthermore, the IMF and SCF had favourable PUFA/saturated fatty acid ratios (>0.4) and omega‐6/omega‐3 ratios (<4), indicating that both components are healthy lipid food sources.CONCLUSIONThis study has shed new light on the nutritional value of zebra meat, which will not only be important for food product labelling, nutritional education and incorporation into food composition databases, but will also be indispensable for marketing and export purposes. © 2016 Society of Chemical Industry
Unbalanced reduction of nutrient loads has created an offshore gradient from phosphorus to nitrogen limitation in the North Sea
Authors: Burson Amanda , Stomp Maayke , Akil Larissa , Brussaard Corina P. D. , Huisman Jef 
Published: January 2016

AbstractMeasures to reduce eutrophication have often led to a more effective decline of phosphorus (P) than nitrogen (N) concentrations. The resultant changes in riverine nutrient loads can cause an increase in the N : P ratios of coastal waters. During four research cruises along a 450 km transect, we investigated how reductions in nutrient inputs during the past 25 yr have affected nutrient limitation patterns in the North Sea. This revealed a strong offshore gradient of dissolved inorganic N : P ratios in spring, from 375 : 1 nearshore toward 1 : 1 in the central North Sea. This gradient was reflected in high nearshore N : P and C : P ratios of particulate organic matter (mainly phytoplankton), indicative of severe P deficiency of coastal phytoplankton, which may negatively affect higher trophic levels in the food web. Nutrient enrichment bioassays performed on‐board showed P and Si limitation of phytoplankton growth nearshore, co‐limitation of N and P in a transitional region, and N limitation in the outer‐shore waters, confirming the existence of an offshore gradient from P to N limitation. Different species were limited by different nutrients, indicating that further reductions of P loads without concomitant reductions of N loads will suppress colonial Phaeocystis blooms, but will be less effective in diminishing harmful algal blooms by dino‐ and nanoflagellates. Hence, our results provide evidence that de‐eutrophication efforts in northwestern Europe have led to a large imbalance in the N : P stoichiometry of coastal waters of the North Sea, with major consequences for the growth, species composition, and nutritional quality of marine phytoplankton communities.
Phase Transition in Hydrogels of Thermoresponsive Interpenetrating Polymer Networks
Authors: Spěváček Jiří , Hanyková Lenka 
Published: January 2016

SummaryWe compared behavior of hydrogels of two types of thermoresponsive interpenetrating polymer networks (IPN), PNIPMAm/PNIPAm and PVCL/PNIPAm, during their phase transition. One or two transitions, depending on the ratio of both IPN components, were found by NMR and DSC. SANS results showed that compact multi‐chain globules with gyration radius ∼20 nm are formed in collapsed IPN hydrogels. A certain portion of spatially restricted bound water (HDO) was established for all studied IPNs in the phase transition region and at temperatures above the phase transition by NMR methods. Fraction of bound water slowly decreases with time. The separate signal of bound water in NMR spectra appears already in pretransition region at temperatures when polymer segments just begin to form collapsed structures. Higher content of bound water as found for collapsed PVCL/PNIPAm hydrogels in comparison with PNIPMAm/PNIPAm hydrogels is in accord with swelling experiments and lower values of the shear mechanical modulus, and shows the decisive role of bound water in this respect.
Targeting MIF in Cancer: Therapeutic Strategies, Current Developments, and Future Opportunities
Authors: O'Reilly Ciaran , Doroudian Mohammad , Mawhinney Leona , Donnelly Seamas C. 
Published: January 2016

AbstractStrong evidence has been presented linking chronic inflammation to the onset and pathogenesis of cancer. The multifunctional pro‐inflammatory protein macrophage migration inhibitory factor (MIF) occupies a central role in the inflammatory pathway and has been implicated in the tumorigenesis, angiogenesis, and metastasis of many cancer phenotypes. This review highlights the current state of the art, which presents MIF, and the second member of the MIF structural superfamily, d‐DT (MIF2), as significant mediators in the inflammatory–cancer axis. Although the mechanism by which MIF asserts its biological activity has yet to be fully understood, it has become clear in recent years that for certain phenotypes of cancer, MIF represents a valid therapeutic target. Current research efforts have focused on small molecule approaches that target MIF's unique tautomerase active site and neutralization of MIF with anti‐MIF antibodies. These approaches have yielded promising results in a number of preclinical murine cancer models and have helped to increase our understanding of MIF biological activity. More recently, MIF's involvement in a number of key protein–protein interactions, such as with CD74 and HSP90, has been highlighted and provides a novel platform for the development of anti‐MIF chemotherapeutic strategies in the future.
Role of vitamin D in adipose tissue in obese rats programmed by early weaning and post diet calcium
Authors: Nobre Jessica Lopes , Lisboa Patricia C. , Peixoto‐Silva Nayara , Quitete Fernanda Torres , Carvalho Janaine C. , de Moura Egberto Gaspar , de Oliveira Elaine 
Published: January 2016

ScopeEarly weaning (EW) is associated with an impairment of offspring development and leads to overweight and higher 25‐hydroxyvitamin D (25(OH)D) levels in adulthood, which can be corrected by calcium supplementation, potentially via vitamin D regulation of adipogenesis.Methods and ResultsWe examined vitamin D status in adipose tissue in EW obese rats, treated with calcium. Dams were separated into: EW‐ dams were wrapped with a bandage to interrupt lactation (last 3 days), and C‐ pups with free access to milk. At PN120, EW pups were divided in: EW‐ standard diet, and EWCa‐ calcium supplementation (10 g of calcium carbonate/kg of chow). On PN21, EW group has hypocalcemia. On PN180, EW group showed lower intestinal calbidin, higher adiposity, and 25(OH)D. In adipose tissue, Cyp27b1/1alpha‐Hydroxylase, C/EBPB, PPAR‐γ, IL6, TNF‐A, and MCP1 were increased, while VDR and IL10 were decreased. Calcium increased calbidin, VDR and prevented adipose tissue dysfunction. EW group has a long‐term effect of vitamin D on adipocyte, contributing to pro‐inflammatory status and obesity.ConclusionWe propose that in obese rat adipocytes, 1,25(OH)2D down‐regulates VDR, resulting in vitamin D resistance, characterized by higher Cyp27b1/1α‐Hydroxylase and adipogenesis. Calcium therapy appears to be an outstanding strategy for weight loss and improving endocrine metabolic disorders that are obesity associated.
Accelerated exponential parameterization of T2 relaxation with model‐driven low rank and sparsity priors (MORASA)
Authors: Peng Xi , Ying Leslie , Liu Yuanyuan , Yuan Jing , Liu Xin , Liang Dong 
Published: January 2016

PurposeThis work is to develop a novel image reconstruction method from highly undersampled multichannel acquisition to reduce the scan time of exponential parameterization of T2 relaxation.Theory and MethodsOn top of the low‐rank and joint‐sparsity constraints, we propose to exploit the linear predictability of the T2 exponential decay to further improve the reconstruction of the T2‐weighted images from undersampled acquisitions. Specifically, the exact rank prior (i.e., number of non‐zero singular values) is adopted to enforce the spatiotemporal low rankness, while the mixed L2–L1 norm of the wavelet coefficients is used to promote joint sparsity, and the Hankel low‐rank approximation is used to impose linear predictability, which integrates the exponential behavior of the temporal signal into the reconstruction process. An efficient algorithm is adopted to solve the reconstruction problem, where corresponding nonlinear filtering operations are performed to enforce corresponding priors in an iterative manner.ResultsBoth simulated and in vivo datasets with multichannel acquisition were used to demonstrate the feasibility of the proposed method. Experimental results have shown that the newly introduced linear predictability prior improves the reconstruction quality of the T2‐weighted images and benefits the subsequent T2 mapping by achieving high‐speed, high‐quality T2 mapping compared with the existing fast T2 mapping methods.ConclusionThis work proposes a novel fast T2 mapping method integrating the linear predictable property of the exponential decay into the reconstruction process. The proposed technique can effectively improve the reconstruction quality of the state‐of‐the‐art fast imaging method exploiting image sparsity and spatiotemporal low rankness. Magn Reson Med 76:1865–1878, 2016. © 2016 International Society for Magnetic Resonance in Medicine
Second‐order motion compensated PRESS for cardiac spectroscopy
Authors: Fuetterer Maximilian , Stoeck Christian T. , Kozerke Sebastian 
Published: January 2016

PurposeSecond‐order motion compensation for point‐resolved spectroscopy (PRESS) is proposed to allow for robust single‐voxel cardiac spectroscopy throughout the entire cardiac cycle and at various heart rates.MethodsBipolar FID spoiling gradient pairs compensating for first and second‐order motion were designed and implemented into a cardiac‐triggered PRESS sequence on a clinical MR system. A numerical three‐dimensional model of cardiac motion was used to optimize and validate the gradient waveforms. In vivo measurements in healthy volunteers were obtained to assess the signal‐to‐noise ratio (SNR) and triglyceride‐to‐water ratio (TG/W). SNR gains and variability of TG/W of the proposed approach were evaluated against a conventional PRESS sequence with optimized gradients.ResultsThe proposed sequence increases the mean SNR by 32% (W) and 23% (TG) on average with significantly lower variability for different trigger delays. The variability of TG/W quantification over the cardiac cycle is significantly decreased with second‐order motion compensated PRESS when compared with conventional PRESS with reduced‐spoiler gradients (coefficient of variation: 0.1 ± 0.02 versus 0.37 ± 0.26).ConclusionSecond‐order motion compensated PRESS effectively reduces cardiac motion–induced signal degradation during FID spoiling, providing higher SNR and less variability for TG/W quantification. The sequence is considered promising to assess the TG/W modulation during various interventions including pharmacologically induced stress. Magn Reson Med 77:57–64, 2017. © 2016 Wiley Periodicals, Inc.
Direct comparison of 129Xe diffusion measurements with quantitative histology in human lungs
Authors: Thomen Robert P. , Quirk James D. , Roach David , Egan‐Rojas Tiffany , Ruppert Kai , Yusen Roger D. , Altes Talissa A. , Yablonskiy Dmitriy A. , Woods Jason C. 
Published: January 2016

PurposeChronic obstructive pulmonary disease (COPD) is an irreversible lung disease characterized by small‐airway obstruction and alveolar‐airspace destruction. Hyperpolarized 129Xe diffusion MRI of lung is a promising biomarker for assessing airspace enlargement, but has yet to be validated by direct comparison to lung histology. Here we have compared diffusion measurements of hyperpolarized (HP) 129Xe in explanted lungs to regionally matched morphological measures of airspace size.MethodsExplanted lungs from five COPD patients and two idiopathic pulmonary fibrosis (IPF) patients were imaged using MRI with hyperpolarized 129Xe using a two‐b‐value gradient‐echo diffusion sequence, and 34 histological samples were taken from these lungs for quantitative histology. Mean‐linear‐intercept (Lm) was compared with spatially matched measures of apparent diffusion coefficient (ADC) from 129Xe MRI.ResultsThe mean ADC from COPD lung samples was 0.071 ± 0.011 cm2/s, and for IPF lungs was 0.033 ± 0.001 cm2/s (P < 10−15 between groups). The mean Lm in COPD samples was 0.076 ± 0.027 cm and 0.041 ± 0.004 cm in IPF (P = 2.7 × 10−7 between groups). The Pearson‐correlation between ADC and Lm measurements was r = 0.59.ConclusionsDiffusion MRI of HP 129Xe quantifies regional airspace enlargement in COPD. 129Xe ADC showed much less overlap between groups than quantitative histology, consistent with our past experience with 3He diffusion MRI in COPD. Magn Reson Med 77:265–272, 2017. © 2016 Wiley Periodicals, Inc.
Effect of interpolation on noise propagation from images to DIC displacement maps
Authors: Blaysat B. , Grédiac M. , Sur F. 
Published: January 2016

SummaryThis paper introduces and validates a new prediction of sensor noise propagation from images of randomly marked surfaces to displacement maps obtained by digital image correlation (DIC). Images are indeed often affected by sensor noise, which propagates to DIC output. We consider here the 2D global DIC, for which this output is the in‐plane displacement calculated at a set of nodes. Predictive formula for the resolution of the displacement at these nodes is already available in the literature. The contribution of the present paper is to revisit this formula to take into account the interpolation required by sub‐pixel displacement. A generalization is also proposed to predict the displacement resolution throughout the field of view. It is then extended to several kinds of DIC. The correlation procedure is thoroughly described in order to emphasize the role of the interpolation. A numerical assessment on synthetic data validates the new prediction and shows the improvement brought about by the proposed formula. Copyright © 2016 John Wiley & Sons, Ltd.
Novel Natural Oximes and Oxime Esters with a Vibralactone Backbone from the Basidiomycete Boreostereum vibrans
Authors: Chen He‐Ping , Zhao Zhen‐Zhu , Li Zheng‐Hui , Dong Ze‐Jun , Wei Kun , Bai Xue , Zhang Ling , Wen Chun‐Nan , Feng Tao , Liu Ji‐Kai 
Published: January 2016

AbstractA variety of novel natural products with significant bioactivities are produced by the basidiomycete Boreostereum vibrans. In the present study, we describe 16 novel natural oximes and oxime esters with a vibralactone backbone, vibralactoximes, which were isolated from the scale‐up fermentation broth of B. vibrans. Their structures were determined through extensive spectroscopic analyses. These compounds represent the first oxime esters from nature. The hypothetical biosynthetic pathway of these compounds was also proposed. Seven compounds exhibited significant pancreatic lipase inhibitory activity, while ten compounds exhibited cytotoxicities against five human cancer cell lines (HL‐60, SMMC‐7721, A‐549, MCF‐7, and SW480), with IC50 values comparable with those of cisplatin.
Comparison of Reductive Ligation‐Based Detection Strategies for Nitroxyl (HNO) and S‐Nitrosothiols
Authors: Miao Zhengrui , King S. Bruce 
Published: January 2016

AbstractPhosphine‐based detection strategies for both nitroxyl (HNO) and S‐nitrosothiols (RSNO) were investigated and compared. Phosphorus NMR studies show that azaylides derived from HNO or organic RSNO efficiently participate in subsequent reductive ligation required for fluorescence generation in properly substituted substrates. S‐Azaylides derived from biological RSNO containing free amine and carboxylic acid groups primarily yield phosphine oxides suggesting these groups facilitate nonligation pathways such as hydrolysis. The fluorescence response of a phosphine‐based fluorophore toward the same RSNO confirms these differences and indicates that these probes selectively react with HNO. Flow cytometry experiments in HeLa cells reinforce the reactivity difference and offer a potential fast screening approach for endogenous HNO sources.