bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enantiomeric Enrichments via the Self‐Disproportionation of Enantiomers (SDE) by Achiral, Gravity‐Driven Column Chromatography: a Case Study Using N‐(1‐Phenylethyl)acetamide for Optimizing the Enantiomerically Pure Yield and Magnitude of the SDE
Authors: Wzorek Alicja , Sato Azusa , Drabowicz Józef , Soloshonok Vadim A. , Klika Karel D. 
Published: August 2015

AbstractThis work explores the self‐disproportionation of enantiomers (SDE) via achiral, gravity‐driven column chromatography as typically used in laboratory settings for the purpose of enantiomeric enrichment using N‐(1‐phenylethyl)acetamide (PEA) as a case study. The major finding of this work is the very large magnitude of the SDE for PEA across a variety of conditions and broad range of starting ee values, thereby facilitating a simple, reliable, and predictable means of obtaining enantiomerically pure samples. For example, starting with a sample of PEA of ee as low as 28%, a single column run yielded an enantiomerically pure sample (>99.9% ee) from the first fractions and a significantly enantiomerically depleted sample (<17% ee) from the final fractions. An assessment of SDE via achiral, gravity‐driven column chromatography was also rendered with regard to the differing objectives that workers might target – a large magnitude of the SDE, obtaining an optimum sample of desired ee, or preparative‐scale separation of the excess enantiomer. Overall, it can be considered that the SDE phenomenon via achiral, gravity‐driven column chromatography – readily applicable in the usual laboratory settings – is a simple and convenient method for enantiomeric enrichment with a high degree of proficiency. Advantages of SDE via achiral, gravity‐driven column chromatography over conventional fractional recrystallization for the enantiomeric enrichment of amides/amines, and applicable also to many other classes of compounds as well, are discussed.
Synthesis of Benzobis[1,3]oxathiins
Authors: Mayer Axel , Rumpf Norbert , Hillmann Sabine , Meier Herbert 
Published: August 2015

AbstractTwo different synthetic concepts led to the formation of 17, 19, and 29, the first structural isomeric benzobis[1,3]oxathiins. Hetero‐DielsAlder reactions of diethyl mesoxylate 14 and the open valence isomers of the benzobisthietes 12 and 18 yielded the linear benzobis[1,3]oxathiin 17 and its angular isomer 22, respectively. The isomeric angular system 29 could be obtained by a twofold O,S‐acetalization reaction of the dihydroxydisulfanyl compound 27 and acetone (28).
Flavonoids Isolated from Heat‐Processed Epimedium koreanum and Their Anti‐HIV‐1 Activities
Authors: Li Hong‐Mei , Zhou Cheng , Chen Chin‐Ho , Li Rong‐Tao , Lee Kuo‐Hsiung 
Published: August 2015

AbstractSystematic phytochemical investigation on heat‐processed Epimedium koreanum led to the isolation of 13 flavonoids, including five new prenyl‐flavonol glycosides, koreanosides A–E (1–5, resp.). Their structures were elucidated on the basis of detailed analysis of the 1D‐ and 2D‐NMR spectroscopic data and chemical reactions. Apigenin (11) exhibited moderate anti‐HIV‐1 activity with an EC50 value of 12.8±3.27 μg/ml.
Established methods and new opportunities for pore water stable isotope analysis
Authors: Sprenger Matthias , Herbstritt Barbara , Weiler Markus 
Published: August 2015

AbstractThe vadose zone plays a crucial role in the water cycle for storing water, providing water to vegetation and transporting solutes or degrading contaminants. Earth scientists have long acknowledged the importance of the vadose zone, and numerous methods have been developed to better understand and predict hydrological processes within this ‘critical zone’. For several decades, stable isotopes (18O and 2H) of pore water have been used as environmental tracers to gain insights into vadose zone water movement and other processes. To determine the pore water stable isotopic composition, various sampling procedures have been developed. We present the procedure and the accompanied advantages and drawbacks of each method. We further discuss possible opportunities and limitations regarding the scale of interest and the pore space that is sampled. The methodological review reveals that the choice of sampling method is crucial for the interpretation of pore water stable isotopes in the vadose zone, but a thorough comparison between the different methods is yet missing. Spiking experiments, where water of known isotopic composition is added to oven‐dried soil, have been shown to be questionable, as the extracted water is usually depleted compared with the standard water. A comparative study analysing soil samples with the recently developed direct water vapour equilibration method and the widely used cryogenic extraction shows deviations, which can only be partly explained, but discloses the need for a more thorough experimental comparative study. Especially promising are developments of continuous isotope measurements based on laser‐based spectrometry that will open up new opportunities for analysing pore water isotopes with higher temporal and spatial resolutions, revealing new insights into hydrological processes across various temporal and spatial scales. Copyright © 2015 John Wiley & Sons, Ltd.
Trends in mean and extreme precipitation in the Mount Kenya region from observations and reanalyses
Authors: Schmocker J. , Liniger H. P. , Ngeru J. N. , Brugnara Y. , Auchmann R. , Brönnimann S. 
Published: August 2015

ABSTRACTLand and water management in semi‐arid regions requires detailed information on precipitation distribution, including extremes, and changes therein. Such information is often lacking. This paper describes statistics of mean and extreme precipitation in a unique data set from the Mount Kenya region, encompassing around 50 stations with at least 30 years of data. We describe the data set, including quality control procedures and statistical break detection. Trends in mean precipitation and extreme indices calculated from these data for individual rainy seasons are compared with corresponding trends in reanalysis products. From 1979 to 2011, mean precipitation decreased at 75% of the stations during the ‘long rains’ (March to May) and increased at 70% of the stations during the ‘short rains’ (October to December). Corresponding trends are found in the number of heavy precipitation days, and maximum of consecutive 5‐day precipitation. Conversely, an increase in consecutive dry days within both main rainy seasons is found. However, trends are only statistically significant in very few cases. Reanalysis data sets agree with observations with respect to interannual variability, while correlations are considerably lower for monthly deviations (ratios) from the mean annual cycle. While some products well reproduce the rainfall climatology and some the spatial trend pattern, no product reproduces both.
Optical spectroscopic determination of human meniscus composition
Authors: Ala‐Myllymäki Juho , Honkanen Juuso T.J. , Töyräs Juha , Afara Isaac O. 
Published: August 2015

ABSTRACTThis study investigates the correlation between the composition of human meniscus and its absorption spectrum in the visible (VIS) and near infrared (NIR) spectral range. Meniscus samples (n = 24) were obtained from nonarthritic knees of human cadavers with no history of joint diseases. Specimens (n = 72) were obtained from three distinct sections of the meniscus, namely; anterior, center, posterior. Absorption spectra were acquired from each specimen in the VIS and NIR spectral range (400–1,100 nm). Following spectroscopic probing, the specimens were subjected to biochemical analyses to determine the matrix composition, that is water, hydroxyproline, and uronic acid contents. Multivariate analytical techniques, including principal component analysis (PCA) and partial least squares (PLS) regression, were then used to investigate the correlation between the matrix composition and it spectral response. Our results indicate that the optical absorption of meniscus matrix is related to its composition, and this relationship is optimal in the NIR spectral range (750–1,100 nm). High correlations (R2uronic = 86.9%, R2water = 83.8%, R2hydroxyproline = 81.7%, p < 0.0001) were obtained between the spectral predicted and measured meniscus composition, thus suggesting that spectral data in the NIR range can be utilized for estimating the matrix composition of human meniscus. In conclusion, optical spectroscopy, particularly in the NIR spectral range, is a potential method for evaluating the composition of human meniscus. This presents a promising technique for rapid and nondestructive evaluation of meniscus integrity in real‐time during arthroscopic surgery. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:270–278, 2016.
Sustained release of bioactive protein from a lyophilized tissue‐engineered construct promotes the osteogenic potential of mesenchymal stem cells
Authors: Deng Moyuan , Chang Zhengqi , Hou Tianyong , Dong Shiwu , Pang Hao , Li Zhiqiang , Luo Fei , Xing Junchao , Yu Bo , Yi Shaoxuan , Xu Jianzhong 
Published: August 2015

ABSTRACTTissue‐engineered constructs (TECs) seeded with mesenchymal stem cells (MSCs) represent a therapy for large bone defects. However, massive cell death in TECs in the early postimplantation period prompted us to investigate the osteoinductive mechanism of TECs. Previous studies demonstrated that stem cell extracts retained equivalent levels of bioactive proteins and exhibited an osteoinductive nature similar to that of intact cells. These data led us to hypothesize that despite the massive cell death in TECs, devitalized MSC‐derived proteins remain on the scaffolds and are released to improve cell function. Here, TECs were prepared using demineralized bone matrix seeded with human umbilical cord Wharton's jelly‐derived MSCs (hWJMSCs), and the cells seeded in TECs were devitalized by lyophilizing the TECs. Scanning electron microscopy, BCA protein assays, quantitative cytokine array analysis and immunofluorescent staining indicated that approximately 3 mg/cm3 of total protein and 49 types of cytokines derived from hWJMSCs were preserved in the lyophilized TECs (LTECs). The sustainable release of total protein and cytokines from LTECs lasted for more than 2 weeks. The released protein improved the osteogenic behavior of and gene expression in MSCs. Furthermore, the lyophilized hWJMSC‐derived proteins had immunoregulatory properties similar to those of live MSCs in mixed lymphocyte reactions. Collectively, we present a novel perspective on the osteoinductive mechanism of TECs and introduce LTECs as new systems for delivering multiple cytokines to enhance MSC behavior. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:386–394, 2016.
Improving access and timeliness of care for veterans with head and neck squamous cell carcinoma: A multidisciplinary team's approach
Authors: Patil Reena Dhanda , Meinzen‐Derr Jareen K. , Hendricks Brian L. , Patil Yash J. 
Published: August 2015

Objectives/HypothesisWith the prevalence of head and neck squamous cell carcinoma (HNSCC) nearly twice as high in veterans (6%) than general populations (3%), the noted problems of long waits and access to care in United States Veterans Affairs (VA) hospitals across the country are pressing. We examined primary outcome measures of timeliness and access to care for our patients with HNSCC assessing a multidisciplinary team approach at our VA hospital.Study DesignRetrospective chart review.MethodsOur patients newly diagnosed with HNSCC were identified from two 24‐month periods: diagnosis before (group 1, 2005–2006) and after (group 2, 2008–2009) implementing our multidisciplinary team in 2007. No significant differences in age (P = .13) or disease stage (P = .18) occurred between groups. Primary and secondary outcomes (i.e., treatment modality, imaging, completion of treatment, survival) were compared.ResultsTimeliness to care improved for all measures. Improvement was significant for times from consult placed to seen in clinic (27.5–16.5 days; P < 0.0001) and from positive biopsy reported to date of initiating definitive treatment (35–27 days; P = 0.04). Pretreatment consults to various services represented by the multidisciplinary team increased from one to four (P < 0.0001). Two‐year mortality was approximately the same between group 1 (33%) and group 2 (36%) (P = 0.035). Five‐year mortality was slightly better in group 2 (50%) versus group 1 (61%), although not statistically significant.ConclusionOur veteran population with HNSCC had improved timeliness and access to care with our multidisciplinary approach.Level of Evidence4. Laryngoscope, 126:627–631, 2016
High‐frequency sensorineural hearing loss in children
Authors: Johnson Kaalan , Tabangin Meredith , Meinzen‐Derr Jareen , Cohen Aliza P. , Greinwald John H. 
Published: August 2015

Objectives/HypothesisDetermine the prevalence of high‐frequency sensorineural hearing loss (HFSNHL) in our hearing loss population and a diagnostic algorithm for these patients.Study DesignRetrospective case series.MethodsWe identified patients diagnosed with sensorineural hearing loss (SNHL) at our pediatric tertiary care institution from 1981 to 2010. Based on audiometric profiles, these patients were subdivided into those with a flat SNHL configuration and those with HFSNHL. Imaging and genetic testing data and data regarding age at diagnosis, laterality, and risk factors were obtained for both groups. Comparisons were then made between the two groups.ResultsOf 2,867 patients included in the study, 7.6% had HFSNHL. Age at diagnosis was significantly higher in HFSNHL patients (8.3 years vs. 6.1 years; P < .0001). These patients also had a significantly higher proportion of unilateral versus bilateral loss (49.1% vs. 26.1%; P < .0001); unilateral losses were also less severe. Genetic testing showed no significant difference between groups in the proportion of patients tested or in those who tested positive. Similarly, imaging data revealed no difference in the proportion of patients tested in the two groups; however, overall diagnostic yield was significantly higher in flat SNHL patients (29.5% vs.17.3; P = .02).ConclusionsThe positive predictive value of simple genetic testing is similar to that of imaging studies. However, given cost differences between genetic testing and imaging, it is prudent to perform genetic testing as the initial diagnostic test. Determination of whether high‐throughput, multigene diagnostic platforms offer an added benefit in the evaluation of children requires further study.Level of Evidence4. Laryngoscope, 126:1236–1240, 2016
A low‐cost transcervical laryngeal injection trainer
Authors: Cabrera‐Muffly Cristina , Clary Matthew S. , Abaza Mona 
Published: August 2015

Objectives/HypothesisTo develop a low‐cost, easy‐to‐construct model for education in transcervical laryngeal injection techniques. To validate the simulator among both fellowship‐trained laryngologists and otolaryngology resident learners.Study DesignSurvey.MethodsA transcervical laryngeal injection model was constructed. Fourteen otolaryngology residents used the model to practice vocal fold injection techniques. Survey feedback was obtained from all residents.ResultsMost learners agreed or strongly agreed that the simulator was easy to use (93%), was a good method to learn transcervical laryngeal injection technique (79%), improved their confidence with the procedure (78%), and could be applied to patients (72%). One hundred percent of the learners agreed or strongly agreed that they would recommend the simulator to other learners.ConclusionResidents can be taught transcervical laryngeal injection techniques with a low‐cost, easily constructed simulator prior to treating patients. This allows for a low‐stress environment in which the learner can practice injection techniques. Resident feedback about the transcervical laryngeal injection simulator was very positive, including unanimous recommendation for use in other learners.Level of EvidenceN/A. Laryngoscope, 126:901–905, 2016
Convergence of Random to Power‐Law Networks Using a Multi‐objective Non‐linear Programming Model
Authors: Petridis Nikolaos E. 
Published: August 2015

AbstractNetworks are a powerful and useful tool for analysing complex systems. Three main types of networks have been proposed in the relative literature in order to interpret adequately evolving or stationary phenomena. In this research, two network structures are analysed; the first type is the random network, which was initially introduced by Erdos and Rényi. Random networks properties remain the same over time, and they do not exhibit high degree of clustering, whereas the second structure studied, the power‐law network that have been examined by Albert and Barabási, can incorporate attributes that are observed in natural networks (i.e. the World Wide Web and the authors' collaboration). In this study, an attempt is made to investigate the conditions under which random network and power law (or scale free) converge into one at a given time point. Three main metrics are used in order to examine the proximity between the studied structures: (i) clustering coefficient, (ii) average path length and (iii) degree distribution. Considering the difference of the corresponding metrics of each network type as an objective function, a multi‐objective discontinuous non‐linear programming model is employed using the weighted sum model as a solution approach. A statistical meta‐analysis is performed using a multivariate logit model in order to assess the effect of each network's specific variables on the objective function. Copyright © 2015 John Wiley & Sons, Ltd.
Assessment of the utility of contact‐based restraints in accelerating the prediction of protein structure using molecular dynamics simulations
Authors: Raval Alpan , Piana Stefano , Eastwood Michael P. , Shaw David E. 
Published: August 2015

AbstractMolecular dynamics (MD) simulation is a well‐established tool for the computational study of protein structure and dynamics, but its application to the important problem of protein structure prediction remains challenging, in part because extremely long timescales can be required to reach the native structure. Here, we examine the extent to which the use of low‐resolution information in the form of residue–residue contacts, which can often be inferred from bioinformatics or experimental studies, can accelerate the determination of protein structure in simulation. We incorporated sets of 62, 31, or 15 contact‐based restraints in MD simulations of ubiquitin, a benchmark system known to fold to the native state on the millisecond timescale in unrestrained simulations. One‐third of the restrained simulations folded to the native state within a few tens of microseconds—a speedup of over an order of magnitude compared with unrestrained simulations and a demonstration of the potential for limited amounts of structural information to accelerate structure determination. Almost all of the remaining ubiquitin simulations reached near‐native conformations within a few tens of microseconds, but remained trapped there, apparently due to the restraints. We discuss potential methodological improvements that would facilitate escape from these near‐native traps and allow more simulations to quickly reach the native state. Finally, using a target from the Critical Assessment of protein Structure Prediction (CASP) experiment, we show that distance restraints can improve simulation accuracy: In our simulations, restraints stabilized the native state of the protein, enabling a reasonable structural model to be inferred.
Observed surface lysine acetylation of human carbonic anhydrase II expressed in Escherichia coli
Authors: Mahon Brian P. , Lomelino Carrie L. , Salguero Antonieta L. , Driscoll Jenna M. , Pinard Melissa A. , McKenna Robert 
Published: August 2015

AbstractAcetylation of surface lysine residues of proteins has been observed in Escherichia coli (E. coli), an organism that has been extensively utilized for recombinant protein expression. This post‐translational modification is shown to be important in various processes such as metabolism, stress‐response, transcription, and translation. As such, utilization of E. coli expression systems for protein production may yield non‐native acetylation events of surface lysine residues. Here we present the crystal structures of wild‐type and a variant of human carbonic anhydrase II (hCA II) that have been expressed in E. coli and exhibit surface lysine acetylation and we speculate on the effect this has on the conformational stability of each enzyme. Both structures were determined to 1.6 Å resolution and show clear electron density for lysine acetylation. The lysine acetylation does not distort the structure and the surface lysine acetylation events most likely do not interfere with the biological interpretation. However, there is a reduction in conformational stability in the hCA II variant compared to wild type (∼4°C decrease). This may be due to other lysine acetylation events that have occurred but are not visible in the crystal structure due to intrinsic disorder. Therefore, surface lysine acetylation events may affect overall protein stability and crystallization, and should be considered when using E. coli expression systems.
Security analysis of a homomorphic signature scheme for network coding
Authors: Cheng Chi , Jiang Tao , Liu Yining , Zhang Mingwu 
Published: August 2015

AbstractRecently, Liu and Wang proposed a homomorphic signature scheme for network coding, which was claimed to resist against pollution attacks. However, we show that in Liu and Wang's scheme, after several generations, the adversary is able to launch a successful forgery attack with a high probability. Therefore, Liu and Wang's scheme is not secure. After analyzing the cause of the attack, an improved scheme is given, which can combat against the proposed attack in an efficient way. Copyright © 2015 John Wiley & Sons, Ltd.
Child Illustrators
Authors: Villarreal Alicia , Minton Sylvia , Martinez Miriam 
Published: August 2015

AbstractIn picture books, illustrations often play a critical role in helping authors tell stories. Instruction in the elements of composition including visual, textual, and peritextual features enhances meaning for children when they are given the opportunity to become authors of their own picturebooks. This study was conducted in a fourth grade classroom and discusses the need for teachers to increase children's understanding of the nature of picture books to build visual literacy and simultaneously support children's development as authors. The authors discuss visual features and design elements found within these books. They also present theory and practical implications for the instruction of pictorial devices when children create their own stories through the form of picturebooks. Knowledge of these various devices can promote critical thinking in young writers.