bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of light‐cured, dental‐resin‐based biocomposites
Authors: Okulus Zuzanna , Buchwald Tomasz , Voelkel Adam 
Published: August 2015

ABSTRACTThe dependence of the depth of cure (DOC) and degree of conversion (DC) on the depth of experimental and commercial materials were determined according to ISO 4049 procedure and with the use of Raman spectroscopy, respectively. Moreover, an attempt was made to find the correlation between the DOC and DC and the depth of the material. The hypothesis was that curing time recommended by the manufacturers is appropriate for curing both commercial and experimental materials to achieve comparable values of the examined properties. The impact of the filler characteristic was clearly observed. The longer curing time provides a deeper curing (DOC values) and higher reaction rate (DC); however, the dependence between the DC values and DOC values was not visible. Instead, a logarithmic trend in the relation of the DOC and curing time was clearly observed. The results of this study suggest that the experimental materials give some hope for potential clinical applications and should be further investigated. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42812.
Sensitive determination of glucose in Dulbecco's modified Eagle medium by high‐performance liquid chromatography with 1‐phenyl‐3‐methyl‐5‐pyrazolone derivatization: application to gluconeogenesis studies
Authors: Ling Zhaoli , Xu Ping , Zhong Zeyu , Wang Fan , Shu Nan , Zhang Ji , Tang Xiange , Liu Li , Liu Xiaodong 
Published: August 2015

AbstractA new pre‐column derivative high‐performance liquid chromatography (HPLC) method for determination of d‐glucose with 3‐O‐methyl‐d‐glucose (3‐OMG) as the internal standard was developed and validated in order to study the gluconeogenesis in HepG2 cells. Samples were derivatized with 1‐phenyl‐3‐methy‐5‐pyrazolone at 70°C for 50 min. Glucose and 3‐OMG were extracted by liquid–liquid extraction and separated on a YMC‐Triart C18 column, with a gradient mobile phase composed of acetonitrile and 20 mm ammonium acetate solution containing 0.09% tri‐ethylamine at a flow rate of 1.0 mL/min. The eluate were detected using a UV detector at 250 nm. The assay was linear over the range 0.39–25 μm (R2 = 0.9997, n = 5) and the lower limit of quantitation was 0.39 μm (0.070 mg/mL). Intra‐ and inter‐day precision and accuracy were <15% and within ±3%, respectively. After validation, the HPLC method was applied to investigate the gluconeogenesis in Dulbecco's modified Eagle medium (DMEM) cultured HepG2 cells. Glucose concentration was determined to be about 1–2.5 μm in this gluconeogenesis assay. In conclusion, this method has been shown to determine small amounts of glucose in DMEM successfully, with lower limit of quantitation and better sensitivity when compared with common commercial glucose assay kits. Copyright © 2015 John Wiley & Sons, Ltd.
Competitive Exclusion Principle in Ecology and Absolute Asymmetric Synthesis in Chemistry
Authors: Ribó Josep M. , Hochberg David 
Published: August 2015

AbstractThe key concepts underlying the Frank model (1953) for spontaneous asymmetric synthesis in chemistry are traced back to the pioneering works of Volterra (1926) and Lotka (1932) on biological species competition. The Lotka‐Volterra (L‐V) two‐species exclusive competition model reduces to the Frank model for the special case of distinguishable but degenerate species (i.e., the enantiomers). The important ecological principle of competitive exclusion, originally derived from the L‐V two‐competitors model, is a consequence of sufficiently antagonistic interactions between the species competing for limited common resources, or mutual inhibition, as the term is known in the chemical literature on absolute asymmetric synthesis. The L‐V and Frank models are described by the same general differential equations, nevertheless a crucial thermodynamic distinction between these models is necessary to correlate ecological selection and chemical selectivity arising from 1) the absence of reversibility in biological transformations, in marked contrast to chemical reactions, and 2) the constraints in chemical scenarios on the reaction rate constants required to fulfill the principle of micro‐reversibility. Chirality 27:722–727, 2015. © 2015 Wiley Periodicals, Inc.
Metamorphic remodeling of the olfactory organ of the African clawed frog, Xenopus laevis
Authors: Dittrich Katarina , Kuttler Josua , Hassenklöver Thomas , Manzini Ivan 
Published: August 2015

ABSTRACTThe amphibian olfactory system undergoes massive remodeling during metamorphosis. The transition from aquatic olfaction in larvae to semiaquatic or airborne olfaction in adults requires anatomical, cellular, and molecular modifications. These changes are particularly pronounced in Pipidae, whose adults have secondarily adapted to an aquatic life style. In the fully aquatic larvae of Xenopus laevis, the main olfactory epithelium specialized for sensing water‐borne odorous substances lines the principal olfactory cavity (PC), whereas a separate olfactory epithelium lies in the vomeronasal organ (VNO). During metamorphosis, the epithelium of the PC is rearranged into the adult “air nose,” whereas a new olfactory epithelium, the adult “water nose,” forms in the emerging middle cavity (MC). Here we performed a stage‐by‐stage investigation of the anatomical changes of the Xenopus olfactory organ during metamorphosis. We quantified cell death in all olfactory epithelia and found massive cell death in the PC and the VNO, suggesting that the majority of larval sensory neurons is replaced during metamorphosis in both sensory epithelia. The moderate cell death in the MC shows that during the formation of this epithelium some cells are sorted out. Our results show that during MC formation some supporting cells, but not sensory neurons, are relocated from the PC to the MC and that they are eventually eliminated during metamorphosis. Together our findings illustrate the structural and cellular changes of the Xenopus olfactory organ during metamorphosis. J. Comp. Neurol. 524:986–998, 2016. © 2015 Wiley Periodicals, Inc.
Getting Off on the Right Foot: The Many Roles of the Psychosocial Evaluation in the Bariatric Surgery Practice
Authors: Sogg Stephanie , Friedman Kelli E. 
Published: August 2015

AbstractA thorough and specialized pre‐operative psychosocial assessment is an important part of a comprehensive bariatric treatment protocol. Over time, the presurgical psychosocial evaluation has evolved from a cut‐and‐dried process of recommending whether a patient should or should not undergo surgery to a more nuanced and multifaceted process that serves multiple functions. In this article, we review the many ways in which the pre‐operative psychosocial evaluation can enhance patient outcomes and adjustment and even the functioning of the interdisciplinary bariatric surgery team. Copyright © 2015 John Wiley & Sons, Ltd and Eating Disorders Association.
Bolus versus continuous infusion of microbubble contrast agent for liver ultrasound by using an automatic power injector in humans: A pilot study
Authors: Quaia Emilio , Gennari Antonio Giulio , Angileri Roberta , Cova Maria Assunta 
Published: August 2015

ABSTRACTPurposeTo evaluate the feasibility of using continuous infusion, in comparison with bolus injection, of a sulfur hexafluoride–microbubble contrast agent to prolong the duration of hepatic parenchymal enhancement in humans during sonographic examination.MethodsThis pilot study was approved by our institution's ethics committee. Ten patients (5 men and 5 women; mean age ± SD, 65 ± 10 years) each received two injections: a bolus injection (2 ml/s) and then continuous infusion (0.5 ml/min) of the contrast agent by using an automatic injector. Acquired cine clips were transferred to a personal computer, and the video intensity was quantified by dedicated software.ResultsFrom the time of the first microbubble visualization in the scanning plane, maximal enhancement was reached in 6.3 ± 0.94 seconds after bolus injection and in 13.9 ± 1.44 seconds during continuous infusion (p = 0.002, Wilcoxon's test for paired data). Compared with bolus injection, continuous infusion prolonged the duration of contrast enhancement (4.3 minutes ± 42 seconds versus 7.3 minutes ± 40 seconds; p = 0.002), although no statistically significant difference in maximal enhancement was observed (45 ± 18% for bolus injection and 39 ± 6% for continuous infusion; p = 0.62).ConclusionsContinuous infusion of sulfur hexafluoride–filled microbubbles via an automatic power injector prolongs hepatic contrast enhancement without significantly modifying the maximal enhancement over that at baseline. These data, coming from a pilot study, can be used to design a larger study with adequate statistical power. © 2015 Wiley Periodicals, Inc. J Clin Ultrasound 44:136–142, 2016
A simple method for selecting spawning‐ready individuals out from laboratorial cultured amphioxus population
Authors: Li Guang , Wang Jing , Yuan Liang , Wang Hui , Wang Yi‐Quan 
Published: August 2015

ABSTRACTAmphioxus is an emerging model organism for evolutionary developmental (Evo‐Dev) studies owing to its key phylogenetic position in chordates. However, the rare supply of living embryonic materials is a major drawback for using amphioxus as a laboratorial model animal. Although the problem has been partially resolved in several recent reports, the spawning of amphioxus still remains unpredictable to some extent. In the present study, we reported an accurate method to distinguish spawning‐ready and non‐spawning‐ready individuals of amphioxus Branchiostoma belcheri. In comparison with non‐spawning‐ready amphioxus, all spawning‐ready individuals display following features several hours before their spawning: 1) for both males and females, the interstices between two adjacent gonads are obvious and relatively wide; and 2) the connections among eggs are loose and the crannies appear in each individual ovary of females. These morphological features were also observed in B. japonicum, indicating their conservation among different lancelet species. Based on this observable criterion, we made predictions on the spawning of about 600 ripe B. belcheri individuals and acquired an accuracy of 86.7% for females and 80.4% for males. In addition, we found that advancing or delaying onset of darkness has no detectable effect on the timing of spawning of B. belcheri. Our study makes amphioxus spawning more amenable for our experiments and will greatly facilitate its utilization as a laboratorial model animal. J. Exp. Zool. (Mol. Dev. Evol.) 324B: 629–635, 2015. © 2015 Wiley Periodicals, Inc.
Individualized evaluation of cholinesterase inhibitors effects in dementia with adaptive cognitive testing
Authors: Wouters Hans , Van Campen Jos P.C.M. , Appels Bregje A. , Beijnen Jos H. , Zwinderman Aeilko H. , Van Gool Willem A. , Schmand Ben 
Published: August 2015

AbstractComputerized Adaptive Testing (CAT) of cognitive function, selects for every individual patient, only items of appropriate difficulty to estimate his or her level of cognitive impairment. Therefore, CAT has the potential to combine brevity with precision. We retrospectively examined the evaluation of treatment effects of cholinesterase inhibitors by CAT using longitudinal data from 643 patients from a Dutch teaching hospital who were diagnosed with Alzheimer disease or Lewy Body disease. The Cambridge Cognitive Examination (CAMCOG) was administered before treatment initiation and after intervals of six months of treatment. A previously validated CAT was simulated using 47 CAMCOG items. Results demonstrated that the CAT required a median number of 17 items (inter‐quartile range 16–20), or a corresponding 64% test reduction, to estimate patients’ global cognitive impairment levels. At the same time, intraclass correlations between global cognitive impairment levels as estimated by CAT or based on all 47 CAMCOG items, ranged from 0.93 at baseline to 0.91–0.94 at follow‐up measurements. Slightly more people had substantial decline on the original CAMCOG (N = 31/285, 11%) than on the CAT (N = 17/285, 6%). We conclude that CAT saves time, does not lose much precision, and therefore deserves a role in the evaluation of treatment effects in dementia. Copyright © 2015 John Wiley & Sons, Ltd.
Prospective acceleration of diffusion tensor imaging with compressed sensing using adaptive dictionaries
Authors: McClymont Darryl , Teh Irvin , Whittington Hannah J. , Grau Vicente , Schneider Jürgen E. 
Published: August 2015

PurposeDiffusion MRI requires acquisition of multiple diffusion‐weighted images, resulting in long scan times. Here, we investigate combining compressed sensing and a fast imaging sequence to dramatically reduce acquisition times in cardiac diffusion MRI.MethodsFully sampled and prospectively undersampled diffusion tensor imaging data were acquired in five rat hearts at acceleration factors of between two and six using a fast spin echo (FSE) sequence. Images were reconstructed using a compressed sensing framework, enforcing sparsity by means of decomposition by adaptive dictionaries. A tensor was fit to the reconstructed images and fiber tractography was performed.ResultsAcceleration factors of up to six were achieved, with a modest increase in root mean square error of mean apparent diffusion coefficient (ADC), fractional anisotropy (FA), and helix angle. At an acceleration factor of six, mean values of ADC and FA were within 2.5% and 5% of the ground truth, respectively. Marginal differences were observed in the fiber tracts.ConclusionWe developed a new k‐space sampling strategy for acquiring prospectively undersampled diffusion‐weighted data, and validated a novel compressed sensing reconstruction algorithm based on adaptive dictionaries. The k‐space undersampling and FSE acquisition each reduced acquisition times by up to 6× and 8×, respectively, as compared to fully sampled spin echo imaging. Magn Reson Med 76:248–258, 2016. © 2015 Wiley Periodicals, Inc.
Free energy landscape of a minimalist salt bridge model
Authors: Li Xubin , Lv Chao , Corbett Karen M. , Zheng Lianqing , Wu Dongsheng , Yang Wei 
Published: August 2015

AbstractSalt bridges are essential to protein stability and dynamics. Despite the importance, there has been scarce of detailed discussion on how salt bridge partners interact with each other in distinct solvent exposed environments. In this study, employing a recent generalized orthogonal space tempering (gOST) method, we enabled efficient molecular dynamics simulation of repetitive breaking and reforming of salt bridge structures within a minimalist salt‐bridge model, the Asp‐Arg dipeptide and thereby were able to map its detailed free energy landscape in aqueous solution. Free energy surface analysis shows that although individually‐solvated states are more favorable, salt‐bridge states still occupy a noticeable portion of the overall population. Notably, the competing forces, e.g. intercharge attractions that drive the formation of salt bridges and solvation forces that pull the charged groups away from each other, are energetically comparable. As the result, the salt bridge stability is highly tunable by local environments; for instance when local water molecules are perturbed to interact more strongly with each other, the population of the salt‐bridge states is likely to increase. Our results reveal the critical role of local solvent structures in modulating salt‐bridge partner interactions and imply the importance of water fluctuations on conformational dynamics that involves solvent accessible salt bridge formations.
Filtration system performance cleaning exhaust air of pneumatic maize seed drills
Authors: Manzone Marco , Tamagnone Mario 
Published: August 2015

AbstractBACKGROUNDIn the agricultural sector, toxic substances can be released into the atmosphere. In recent years, Europe has encountered a significant environmental issue related to the dispersion of pesticides during maize seeding, especially when performed with pneumatic seed drills. This phenomenon can be very dangerous for insects, as the dispersed dust contains pesticides (insecticides, fungicides, etc.) used to dress maize seeds. On the basis of these considerations, experimental tests have been carried out using a filtration system to clean the airflow that exits from the fan of pneumatic maize seed drills.RESULTSThe tested filtration system does not interfere with the seeding quality because the vacuum level observed within the filtration system assembled on the seeder (5.7 kPa) is 27% higher than the correct vacuum level to guarantee good seeding quality (4.2 kPa). In addition, it enables a reduction in the risk of environmental contamination, as no dust deposits were found at different distances from the machine.CONCLUSIONThe use of a filtration system shows advantages in terms of environmental and operator safety because dangerous materials are contained in the filter case, thus avoiding contamination of neighbouring areas and the machinery used (tractor and seed drill). © 2015 Society of Chemical Industry
Protein Kinase-A Inhibition Is Sufficient to Support Human Neural Stem Cells Self-Renewal
Authors: Georges Pauline , Boissart Claire , Poulet Aurélie , Peschanski Marc , Benchoua Alexandra 
Published: August 2015

Abstract
Human pluripotent stem cell-derived neural stem cells offer unprecedented opportunities for producing specific types of neurons for several biomedical applications. However, to achieve it, protocols of production and amplification of human neural stem cells need to be standardized, cost effective, and safe. This means that small molecules should progressively replace the use of media containing cocktails of protein-based growth factors. Here we have conducted a phenotypical screening to identify pathways involved in the regulation of hNSC self-renewal. We analyzed 80 small molecules acting as kinase inhibitors and identified compounds of the 5-isoquinolinesulfonamide family, described as protein kinase A (PKA) and protein kinase G inhibitors, as candidates to support hNSC self-renewal. Investigating the mode of action of these compounds, we found that modulation of PKA activity was central in controlling the choice between self-renewal or terminal neuronal differentiation of hNSC. We finally demonstrated that the pharmacological inhibition of PKA using the small molecule HA1004 was sufficient to support the full derivation, propagation, and long-term maintenance of stable hNSC in absence of any other extrinsic signals. Our results indicated that tuning of PKA activity is a core mechanism regulating hNSC self-renewal and differentiation and delineate the minimal culture media requirement to maintain undifferentiated hNSC in vitro. Stem Cells 2015;33:3666–3672
Potassium and Mixed Lithium/Potassium Complexes of Deprotonated 1,2‐Bis(neopentylamino)benzene
Authors: Ziemann Steffen , Krieck Sven , Görls Helmar , Westerhausen Matthias 
Published: August 2015

AbstractDeprotonation of 1,2‐bis(neopentylamino)benzene (1) with an excess of KH in tetrahydrofuran (thf) yields the singly metalated derivative [(thf)K{C6H4‐1‐(NH‐CH2tBu)‐2‐(N‐CH2tBu)}] (2a). Performance of the metalation reaction in tetrahydropyran (thp) leads to formation of [(thp)2K{C6H4‐1‐(NH‐CH2tBu)‐2‐(N‐CH2tBu)}] (2b). The second amino group of 2a can be lithiated by butyllithium yielding heterobimetallic [(thf)2LiK{C6H4‐1,2‐(N‐CH2tBu)2}] (3). The structures demonstrate that ethers as well as aromatic π systems represent suitable bases for the rather soft potassium ions. Intermolecular potassium π interactions lead to the formation of strands in the crystalline state. For complex 2a, a dynamic exchange process of the N‐bound hydrogen atom with an energy barrier of 45.6 kJ·mol–1 is observed in [D8]THF solution. Heterobimetallic 3 also shows a temperature‐dependent dynamic behavior that gives rise to splitting of the methylene and aromatic resonances suggesting overlying metal exchange and aggregation equilibria.
Are Medical Students Who Want to Become Surgeons Different? An International Cross‐Sectional Study
Authors: Baschera Dominik , O’Donnell Taylor Erin , Masilonyane‐Jones Taolo , Isenegger Patrick , Zellweger René 
Published: August 2015

AbstractIntroductionSurgery is one of the most demanding and competitive medical specialities. This study aims to identify the characteristics that medical students who aspire to surgical specialisation possess.Materials and methodsIn February 2010, an online survey comprised 36 questions was produced with the aid of the open source survey tool Limesurvey (Version 1.85 RC3). Deans’ offices and student organisations in eight countries were contacted via e‐mail with a link to the online survey for them to disseminate amongst the student population. Respondents were grouped into “Surgically inclined” and “non‐surgically inclined”. To compare the characteristics of these two groups, the Fisher Exact test was used for categorical data and non‐parametric tests were used for continuous data.ResultsBetween February and June 2010, we received 2907 responses; the majority from Australia, Austria, Germany, Switzerland and the UK. Of these, 2351 indicated what discipline they would like to pursue after graduation, with 383 (16.3 %) favouring surgery. The percentages of students interested in Surgery were similar across all participating countries. Those favouring Surgery were 1.5 times more likely to be male (*p = 0.01); however, Austria and Germany had significantly higher rates of female students interested in Surgery than all other countries surveyed. Students favouring Surgery were 20 % more likely to be single. Students favouring surgery were more likely to nominate “social prestige” and “remuneration” as their key motivation to become a doctor and were also prepared to work longer hours than respondents that were not surgically inclined.ConclusionIn this study, Medical students who aspire toward surgical careers were more likely to be male, less lifestyle orientated, and seeking social prestige and financial remuneration compared to other medical students.