bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding the relation between structural and mechanical properties of electrospun fiber mesh through uniaxial tensile testing
Authors: Kumar Prasoon , Vasita Rajesh
Published: March 2017

Polymeric electrospun fibers have the potential to be utilized for a variety of applications such as tissue engineering, filtration, and textiles, owing to their high surface area per unit mass. However, these applications have some form of dependency on the mechanical properties of fiber meshes. Therefore, the current study is aimed at understanding the mechanical behavior of electrospun fiber systems at different length scales in order to establish a correlation between their structure and mechanical properties. Micro‐/nano‐fiber meshes of polystyrene were fabricated by the process of electrospinning and were subjected to uniaxial tensile testing. High‐resolution imaging during tensile testing revealed the macroscopic and microscopic structural evolution of these fibers. Further, the dependence of tensile strength, % elongation, and toughness of fiber meshes on the orientation of the fibers were also experimentally observed. The continuum mechanics simulation studies of fiber meshes with different orientations corroborated well with these experimental studies. Comprehensively, these studies demonstrated the changes in mechanical behavior of electrospun fiber meshes owing to the reorientation and alignment of fibers in meshes at microscopic and macroscopic length scale during tensile testing. Such study can be extrapolate for the design and fabrication of load‐bearing tissues scaffolds, and filtration devices. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45012.
Perceived social support in adults with autism spectrum disorder and attention‐deficit/hyperactivity disorder
Authors: Alvarez‐Fernandez Sonia , Brown Hallie R. , Zhao Yihong , Raithel Jessica A. , Bishop Somer L. , Kern Sarah B. , Lord Catherine , Petkova Eva , Di Martino Adriana
Published: March 2017

Perceived social support (PSS) has been related to physical and mental well‐being in typically developing individuals, but systematic characterizations of PSS in autism spectrum disorder (ASD) are limited. We compared self‐report ratings of the multidimensional scale of PSS (MSPSS) among age‐ and IQ‐matched groups of adults (18–58 years) with cognitively high‐functioning ASD (N = 41), or attention‐deficit/hyperactivity disorder (ADHD; N = 69), and neurotypical controls (NC; N = 69). Accompanying group comparisons, we used machine learning random forest (RF) analyses to explore predictors among a range of psychopathological and socio‐emotional variables. Relative to both ADHD and NC, adults with ASD showed lower MSPSS ratings, specifically for the friends subscale (MSPSS‐f). Across ASD and ADHD, interindividual differences in autism severity, affective empathy, symptoms of anxiety related to social interactions, hyperactivity/impulsivity, and somatization best predicted MSPSS‐f. These relationships did not differ between clinical groups. While group comparisons demonstrated greater impairment in individuals with ASD, analyzing individuals' characteristics revealed cross‐diagnoses similarities in regard to their MSPSS‐f relationships. This is consistent with the Research Domain Criteria framework, supporting a trans‐diagnostic approach as on the path toward “precision medicine.” Autism Res 2017, 10: 866–877. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.
Lifelong neurogenesis in the cerebral ganglion of the Chinese mud snail,Cipangopaludina chinensis
Authors: Swart Charles C. , Wattenberger Amelia , Hackett Amy , Isaman Danielle
Published: March 2017

Introduction

A small group of Gastropods possessing giant neurons have long been used to study a wide variety of fundamental neurophysiological phenomena. However, the majority of gastropods do not have large neurons but instead have large numbers of small neurons and remain largely unstudied. We explored neuron size and rate of increase in neuron numbers in the Chinese mud snail,Cipangopaludina chinensis.

Methods

Using histological sections and whole mounts of the cerebral ganglia, we collected cross‐sectional data on neuron number and size across the lifespan of this animal. Neurogenesis was verified using Click‐it EdU staining.

Results

We found that total neuron number in the cerebral ganglia increases throughout the lifespan of this species at a constant rate. New neurons arise primarily near the nerve roots. Females live longer (up to 7 years) than males (up to 5 years) and thus achieve larger numbers of neurons in the cerebral ganglion. Neuron size is consistently small (<10 μm) in the cerebral ganglia at all ages, however, cells in the posterior section of the cerebral ganglia are modestly but significantly larger than cells at the anterior.

Conclusions

These features suggest thatC. chinensisand similar species of Caenogastropoda are good candidates for studying gastropod neurogenesis, senescence, and sex differences in the nervous system.
Porphyrin Donor and Tunable Push–Pull Acceptor Conjugates—Experimental Investigation of Marcus Theory
Authors: Reekie Tristan A. , Sekita Michael , Urner Lorenz M. , Bauroth Stefan , Ruhlmann Laurent , Gisselbrecht Jean‐Paul , Boudon Corinne , Trapp Nils , Clark Timothy , Guldi Dirk M. , Diederich François
Published: March 2017

We report on a series of electron donor–acceptor conjugates incorporating a ZnII–porphyrin‐based electron donor and a variety of non‐conjugated rigid linkers connecting to push–pull chromophores as electron acceptors. The electron acceptors comprize multicyanobutadienes or extended tetracyanoquinodimethane analogues with first reduction potentials ranging from −1.67 to −0.23 V vs. Fc+/Fc in CH2Cl2, which are accessible through a final‐step cycloaddition–retroelectrocyclization (CA‐RE) reaction. Characterization of the conjugates includes electrochemistry, spectroelectrochemistry, DFT calculations, and photophysical measurements in a range of solvents. The collected data allows for the construction of multiple Marcus curves that consider electron‐acceptor strength, linker length, and solvent, with data points extending well into the inverted region. The enhancement of electron–vibration couplings, resulting from the rigid spacers and, in particular, multicyano‐groups in the conformationally highly fixed push–pull acceptor chromophores affects the charge‐recombination kinetics in the inverted region drastically.
Latent variable based concurrent multi‐trends analysis method for monitoring batch processes with irregular and limited batches
Authors: Li Wenqing , Zhao Chunhui
Published: March 2017

In practice, two problems, limited batches and irregular batch trajectories, may simultaneously exist in batch processes, making process modelling and monitoring a great challenge. However, previous work did not solve the two problems simultaneously. Motivated by such cognition, for those processes with limited modelling batches and irregular batch durations, this work proposes a LV (Latent Variable)‐based concurrent multi‐trends analysis method, which combines the advantages of multi‐set variable correlation analysis and trend analysis. First, cross set correlation analysis is implemented to reduce the variable dimensionality and extract the latent variables. Then, temporal evolution trends of latent variables are described by multiple polynomials, formulating multi‐trends models. For online monitoring, the sequential nature also provides an easy but effective way to check the operation status of a new sample. Additionally, a trends based updating strategy is proposed to accommodate normal batch‐wise variations to develop a more reliable monitoring system. The application to a typical batch process with uneven‐length and limited batches illustrates the online monitoring performance of the proposed method.
Cytologic characteristics of circulating epithelioid cells in pancreatic disease
Authors: Rosenbaum Matthew W. , Cauley Christy E. , Kulemann Birte , Liss Andrew S. , Castillo Carlos Fernandez‐del , Warshaw Andrew L. , Lillemoe Keith D. , Thayer Sarah P. , Pitman Martha B.
Published: March 2017

BACKGROUND

Circulating epithelioid cells (CECs), also known as circulating tumor, circulating cancer, circulating epithelial, or circulating nonhematologic cells, are a prognostic factor in various malignancies that can be isolated via various protocols. In the current study, the authors analyzed the cytomorphologic characteristics of CECs isolated by size in a cohort of patients with benign and malignant pancreatic diseases to determine whether cytomorphological features could predict CEC origin.

METHODS

Blood samples were collected from 9 healthy controls and 171 patients with pancreatic disease who were presenting for surgical evaluation before treatment. Blood was processed with the ScreenCell size‐based filtration device. Evaluable CECs were analyzed in a blinded fashion for cytomorphologic characteristics, including cellularity; nucleoli; nuclear size, irregularity, variability, and hyperchromasia; and nuclear‐to‐cytoplasmic ratio. Statistical differences between variables were analyzed via the Fisher exact test.

RESULTS

No CECs were identified among the 9 normal healthy controls. Of the 115 patients with CECs (positive or suspicious for), 25 had nonmalignant disease and 90 had malignancy. There were no significant differences in any of the cytologic criteria noted between groups divided by benign versus malignant, neoplastic versus nonneoplastic, or pancreatic ductal adenocarcinoma versus neuroendocrine tumor.

CONCLUSIONS

CECs were observed in patients with malignant and nonmalignant pancreatic disease, but not in healthy controls. There were no morphologic differences observed between cells from different pancreatic diseases, suggesting that numerous conditions may be associated with CECs in the circulation and that care must be taken not to overinterpret cells identified by cytomorphology as indicative of circulating tumor cells of pancreatic cancer. Additional studies are required to determine the origin and clinical significance of these cells. Cancer Cytopathol 2017;125:332–340. © 2017 American Cancer Society.
Solving dense symmetric indefinite systems using GPUs
Authors: Baboulin Marc , Dongarra Jack , Rémy Adrien , Tomov Stanimire , Yamazaki Ichitaro
Published: March 2017

This paper studies the performance of different algorithms for solving a dense symmetric indefinite linear system of equations on multicore CPUs with a Graphics Processing Unit (GPU). To ensure the numerical stability of the factorization, pivoting is required. Obtaining high performance of such algorithms on the GPU is difficult because all the existing pivoting strategies lead to frequent synchronizations and irregular data accesses. Until recently, there has not been any implementation of these algorithms on a hybrid CPU/GPU architecture. To improve their performance on the hybrid architecture, we explore different techniques to reduce the expensive data transfer and synchronization between the CPU and GPU, or on the GPU (e.g., factorizing the matrix entirely on the GPU or in a communication‐avoiding fashion). We also study the performance of the solver using iterative refinements along with the factorization without pivoting combined with the preprocessing technique based on random butterfly transformations, or with the mixed‐precision algorithm where the matrix is factorized in single precision. This randomization algorithm only has a probabilistic proof on the numerical stability, and for this paper, we only focused on the mixed‐precision algorithm without pivoting. However, they demonstrate that we can obtain good performance on the GPU by avoiding the pivoting and using the lower precision arithmetics, respectively. As illustrated with the application in acoustics studied in this paper, in many practical cases, the matrices can be factorized without pivoting. Because the componentwise backward error computed in the iterative refinement signals when the algorithm failed to obtain the desired accuracy, the user can use these potentially unstable but efficient algorithms in most of the cases and fall back to a more stable algorithm with pivoting only in the case of the failure. Copyright © 2017 John Wiley & Sons, Ltd.
Incorporating selective victim cache into GPGPU for high‐performance computing
Authors: Wang Jianfei , Fan Fengfeng , Jiang Li , Liang Xiaoyao , Jing Naifeng
Published: March 2017

Contemporary general‐purpose graphic processing units (GPGPUs) successfully parallelize an application into thousands of concurrent threads with remarkably improved performance. Such massive threads will compete for the small‐sized first‐level data (L1D) cache, leading to an exaggerated cache‐thrashing problem, which may degrade the overall performance significantly. In this paper, we propose a selective victim cache design to enable better data locality and higher performance. Instead of a small fully associative structure, we first redesign the victim cache as a set associative structure that is equivalent to the original L1D cache to suit the GPGPU applications with massive concurrent threads. To keep the mostly used data in L1D for better operand service, we apply a simple prediction scheme to avoid costly block interchanges and evictions. To further save the area for data storage, we propose to leverage the unallocated registers and shared memory entries to hold the victim cache data. The experiments demonstrate that our proposed approach can increase the on‐chip data cache hit rate considerably and deliver a better performance with negligible changes to the baseline GPGPU architecture. For example, our selective victim cache design can improve the performance by 41.3% on average, achieving 54.7% increase in data cache hit rate and 21.8% reduction in block interchanges and evictions.
Experimental Polymer Mechanochemistry and its Interpretational Frameworks
Authors: Akbulatov Sergey , Boulatov Roman
Published: March 2017

Polymer mechanochemistry is an emerging field at the interface of chemistry, materials science, physics and engineering. It aims at understanding and exploiting unique reactivities of polymer chains confined to highly non‐equilibrium stretched geometries by interactions with their surroundings. Macromolecular chains or their segments become stretched in bulk polymers under mechanical loads or when polymer solutions are sonicated or flow rapidly through abrupt contractions. An increasing amount of empirical data suggests that mechanochemical phenomena are widespread wherever polymers are used. In the past decade, empirical mechanochemistry has progressed enormously, from studying fragmentations of commodity polymers by simple backbone homolysis to demonstrations of self‐strengthening and stress‐reporting materials and mechanochemical cascades using purposefully designed monomers. This progress has not yet been matched by the development of conceptual frameworks within which to rationalize, systematize and generalize empirical mechanochemical observations. As a result, mechanistic and/or quantitative understanding of mechanochemical phenomena remains, with few exceptions, tentative. In this review we aim at systematizing reported macroscopic manifestations of polymer mechanochemistry, and critically assessing the interpretational framework that underlies their molecular rationalizations from a physical chemist's perspective. We propose a hierarchy of mechanochemical phenomena which may guide the development of multiscale models of mechanochemical reactivity to match the breadth and utility of the Eyring equation of chemical kinetics. We discuss the limitations of the approaches to quantifying and validating mechanochemical reactivity, with particular focus on sonicated polymer solutions, in order to identify outstanding questions that need to be solved for polymer mechanochemistry to become a rigorous, quantitative field. We conclude by proposing 7 problems whose solution may have a disproportionate impact on the development of polymer mechanochemistry.
A Guide to Genome‐Wide Association Mapping in Plants
Authors: Burghardt Liana T. , Young Nevin D. , Tiffin Peter
Published: March 2017

Genome‐wide association studies (GWAS) have developed into a valuable approach for identifying the genetic basis of phenotypic variation. In this article, we provide an overview of the design, analysis, and interpretation of GWAS. First, we present results from simulations that explore key elements of experimental design as well as considerations for collecting the relevant genomic and phenotypic data. Next, we outline current statistical methods and tools used for GWA analyses and discuss the inclusion of covariates to account for population structure and the interpretation of results. Given that many false positive associations will occur in any GWA analysis, we highlight strategies for prioritizing GWA candidates for further statistical and empirical validation. While focused on plants, the material we cover is also applicable to other systems. © 2017 by John Wiley & Sons, Inc.
A Complementary Aggregation Induced Emission Pair for Generating White Light and Four‐Colour (RGB and Near‐IR) Cell Imaging
Authors: Sarkar Samir Kumar , Mukherjee Sanjoy , Garai Aditya , Thilagar Pakkirisamy
Published: March 2017

The front cover artwork is provided by the Thilagar group at the Indian Institute of Science in Bangalore. The image shows the principle of forming water‐dispersible nanoparticles by doping a BODIPY‐based red‐light‐emissive AIE‐active dye inside nanoaggregates of a naphthalimide‐based AIE‐active blue‐emissive dye (AIE=aggregation‐induced emission). This white‐light‐emissive nanomaterial was used in the four‐colour visualisation of living cells (from the visible to the near‐IR spectral regions). Read the full text of the article at 10.1002/cptc.201600032.
Poor transferability of a distribution model for a widespread coastal marsh bird in the southeastern United States
Authors: Roach Nicolette S. , Hunter Elizabeth A. , Nibbelink Nathan P. , Barrett Kyle
Published: March 2017

Species distribution models have been applied across a wide range of spatial scales to generate information for conservation planning. Understanding how well models transfer through space and time is important to promote effective species–habitat conservation. Here, we assess model transferability in coastal tidal marshes of the southeastern United States using count data of a widespread marsh bird: the Clapper Rail (Rallus crepitans). We developed species–habitat models at a state level in both South Carolina and Georgia, and then assessed how well top models from each state predicted abundance in the other state. Internally (locally) validated models performed well with reasonable fit (SC: R2 = 0.35, GA: R2 = 0.14), and high significance (P = 0.0005); however, both models performed poorly when predicting abundance from the other state (R2 = 0.03 and 0.003). To assess the consequences of this lack of transferability, we applied the South Carolina‐ and Georgia‐derived parameter estimates to habitat features in South Carolina and identified the top 25% of tidal marsh habitat that each model predicted within the state. There was minimal overlap between model habitat quality predictions (<5%). Our results address the predictive power and uncertainties that arise from using habitat associations and climate models to predict species distributions or abundance in locations without training data. We discuss potential reasons model transferability was not successful and address the need for better regional datasets and the importance of intraspecific variability in response to environmental gradients.
Flexible Ligand‐Based Lanthanide Three‐Dimensional Metal–Organic Frameworks with Tunable Solid‐State Photoluminescence and OH‐Solvent‐Sensing Properties
Authors: Gomez Germán E. , Brusau Elena V. , Kaczmarek Anna M. , Mellot‐Draznieks Caroline , Sacanell Joaquín , Rousse Gwenaelle , Van Deun Rik , Sanchez Clément , Narda Griselda E. , Soler Illia Galo J. A. A.
Published: March 2017

Luminescent 3D metal–organic frameworks (MOFs) constructed from trivalent lanthanides Nd3+, Sm3+, Eu3+, Gd3+, Tb3+ and a flexible ligand, 2‐methylsuccinate, (Ln‐msucc) have been hydrothermally obtained as polycrystalline solids. They were fully characterized by X‐ray powder diffraction, thermal analysis, vibrational spectroscopy, and scanning electron microscopy. The crystalline structure and topological features were elucidated and compared with those of related Ln‐MOFs. The magnetic studies reveal that Nd‐msucc and Gd‐msucc present antiferromagnetic and ferromagnetic behavior, respectively. Moreover, the solid‐state photoluminescence properties of all the compounds were fully explored. Depending on the lanthanide content, these materials exhibited luminescence in the near‐infrared and visible regions. In particular, the photophysical behavior of the Eu phase was exhaustively examined and the radiative and nonradiative constants and intrinsic quantum yields were calculated. The hypersensitive nature of the Eu3+ 5D0→7F2 transition allowed an in‐depth study of the optical response in the presence of various protic and aprotic solvents. As far as we know, the chemical‐sensing studies employing Eu‐msucc constitute the first case reported for a lanthanide succinate‐derived framework. The obtained results are promising for the elaboration of specific chemical sensors based on this material.
Growth medium and electrolyte—How to combine the different requirements on the reaction solution in bioelectrochemical systems using Cupriavidus necator
Authors: Sydow Anne , Krieg Thomas , Ulber Roland , Holtmann Dirk
Published: March 2017

Microbial electrosynthesis is a relatively new research field where microbial carbon dioxide fixation based on the energy supplied by a cathode is investigated. Reaction media used in such bioelectrochemical systems have to fulfill requirements of classical biotechnology as well as electrochemistry. The design and characterization of a medium that enables fast electroautotrophic growth of Cupriavidus necator in microbial electrosynthesis was investigated in detail. The identified chloride‐free medium mainly consists of low buffer concentration and is supplied with trace elements. Biotechnologically relevant parameters, such as high‐specific growth rates and short lag phases, were determined for growth characterization. Fast growth under all conditions tested, i.e. heterotrophic, autotrophic and electroautotrophic was achieved. The lag phase was shortened by increasing the FeSO₄ concentration. Additionally, electrochemical robustness of the reaction media was proven. Under reductive conditions, no deposits on electrodes or precipitations in the media were observed and no detectable hydrogen peroxide evolved. In the bioelectrochemical system, no lag phase occurred and specific growth rate of C. necator was 0.09 h⁻¹. Using this medium shortens seed train drastically and enables fast electrobiotechnological production processes based on C. necator.
Treatment of patients waitlisted for liver transplant with all‐oral direct‐acting antivirals is a cost‐effective treatment strategy in the United States
Authors: Ahmed Aijaz , Gonzalez Stevan A. , Cholankeril George , Perumpail Ryan B. , McGinnis Justin , Saab Sammy , Beckerman Rachel , Younossi Zobair M.
Published: March 2017

All‐oral direct acting antivirals (DAAs) have been shown to have high safety and efficacy in treating patients with hepatitis C virus (HCV) awaiting liver transplant (LT). However, there is limited empirical evidence comparing the health and economic outcomes associated with treating patients pre‐LT versus post‐LT. The objective of this study was to analyze the cost‐effectiveness of pre‐LT versus post‐LT treatment with an all‐oral DAA regimen among HCV patients with hepatocellular carcinoma (HCC) or decompensated cirrhosis (DCC). We constructed decision‐analytic Markov models of the natural disease progression of HCV in HCC patients and DCC patients waitlisted for LT. The model followed hypothetical cohorts of 1,000 patients with a mean age of 50 over a 30‐year time horizon from a third‐party US payer perspective and estimated their health and cost outcomes based on pre‐LT versus post‐LT treatment with an all‐oral DAA regimen. Transition probabilities and utilities were based on the literature and hepatologist consensus. Sustained virological response rates were sourced from ASTRAL‐4, SOLAR‐1, and SOLAR‐2. Costs were sourced from RedBook, Medicare fee schedules, and published literature. In the HCC analysis, the pre‐LT treatment strategy resulted in 11.48 per‐patient quality‐adjusted life years and $365,948 per patient lifetime costs versus 10.39 and $283,696, respectively, in the post‐LT arm. In the DCC analysis, the pre‐LT treatment strategy resulted in 9.27 per‐patient quality‐adjusted life years and $304,800 per patient lifetime costs versus 8.7 and $283,789, respectively, in the post‐LT arm. As such, the pre‐LT treatment strategy was found to be the most cost‐effective in both populations with an incremental cost‐effectiveness ratio of $74,255 (HCC) and $36,583 (DCC). Sensitivity and scenario analyses showed that results were most sensitive to the utility of patients post‐LT, treatment sustained virological response rates, LT costs, and baseline Model for End‐Stage Liver Disease score (DCC analysis only). Conclusion: The timing of initiation of antiviral treatment for HCV patients with HCC or DCC relative to LT is an important area of clinical and policy research; our results indicate that pre‐LT treatment with a highly effective, all‐oral DAA regimen provides the best health outcomes and is the most cost‐effective strategy for the treatment of HCV patients with HCC or DCC waitlisted for LT. (Hepatology 2017;66:46–56).
Substance P increases liver fibrosis by differential changes in senescence of cholangiocytes and hepatic stellate cells
Authors: Wan Ying , Meng Fanyin , Wu Nan , Zhou Tianhao , Venter Julie , Francis Heather , Kennedy Lindsey , Glaser Trenton , Bernuzzi Francesca , Invernizzi Pietro , Glaser Shannon , Huang Qiaobing , Alpini Gianfranco
Published: March 2017

Substance P (SP) is involved in the proliferation of cholangiocytes in bile duct–ligated (BDL) mice and human cholangiocarcinoma growth by interacting with the neurokinin‐1 receptor (NK‐1R). To identify whether SP regulates liver fibrosis during cholestasis, wild‐type or NK‐1R knockout (NK‐1R–/–) mice that received BDL or sham surgery and multidrug resistance protein 2 knockout (Mdr2
–/–) mice treated with either an NK‐1R antagonist (L‐733,060) or saline were used. Additionally, wild‐type mice were treated with SP or saline intraperitoneally. In vivo, there was increased expression of tachykinin precursor 1 (coding SP) and NK‐1R in both BDL and Mdr2
–/– mice compared to wild‐type mice. Expression of tachykinin precursor 1 and NK‐1R was significantly higher in liver samples from primary sclerosing cholangitis patients compared to healthy controls. Knockout of NK‐1R decreased BDL‐induced liver fibrosis, and treatment with L‐733,060 resulted in decreased liver fibrosis in Mdr2
–/– mice, which was shown by decreased sirius red staining, fibrosis gene and protein expression, and reduced transforming growth factor‐β1 levels in serum and cholangiocyte supernatants. Furthermore, we observed that reduced liver fibrosis in NK‐1R–/– mice with BDL surgery or Mdr2
–/– mice treated with L‐733,060 was associated with enhanced cellular senescence of hepatic stellate cells and decreased senescence of cholangiocytes. In vitro, L‐733,060 inhibited SP‐induced expression of fibrotic genes in hepatic stellate cells and cholangiocytes; treatment with L‐733,060 partially reversed the SP‐induced decrease of senescence gene expression in cultured hepatic stellate cells and the SP‐induced increase of senescence‐related gene expression in cultured cholangiocytes. Conclusion: Collectively, our results demonstrate the regulatory effects of the SP/NK‐1R axis on liver fibrosis through changes in cellular senescence during cholestatic liver injury. (Hepatology 2017;66:528–541).
The effect of increasing the pore size of nanofibrous scaffolds on the osteogenic cell culture using a combination of sacrificial agent electrospinning and ultrasonication
Authors: Aghajanpoor Mahdiyeh , Hashemi‐Najafabadi Sameereh , Baghaban‐ Eslaminejad Mohamadreza , Bagheri Fatemeh , Mohammad Mousavi Seyyed , Azam Sayyahpour Foruogh
Published: March 2017

One of the major problems associated with the electrospun scaffolds is their small pore size, which limits the cellular infiltration for bone tissue engineering. In this study, the effect of increasing the pore size on cellular infiltration was studied in poly/nanohydroxyapatite electrospun scaffolds, which were modified using ultrasonication, co‐electrospinning with poly (ethylene oxide), and a combination of both. Ultrasonic process was optimized by central composite design. The ultrasonic output power and time of the process were considered as the effective parameters. The pore size of the scaffolds was evaluated by scanning electron microscope. The optimum conditions, according to the pore area and mechanical properties of the scaffolds were selected, and finally the groups that had the highest pore size and mechanical strength were selected for the combined method. Increasing the pore size enhanced the cellular proliferation, extension and infiltration, as well as the osteodifferentiation of stem cells. At the optimum condition, the average cellular infiltration was 36.51 µm compared to the control group with no cellular infiltration. In addition, alkaline phosphatase activity and the expression of osteocalcin and collagen I (COL I) were, respectively, 1.86, 2.54, and 2.16 fold compared to the control group on day 14. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1887–1899, 2017.
Chitosan‐agarose scaffolds supports chondrogenesis of Human Wharton's Jelly mesenchymal stem cells
Authors: Merlin Rajesh Lal L. P. , Suraishkumar G. K. , Nair Prabha D.
Published: March 2017

Tissue engineering strategies for cartilage aim to restore the complex biomechanical and biochemical properties of the native cartilage. To mimic the in vivo microenvironment, we developed a novel scaffold based on chitosan‐agarose (CHAG scaffold) resembling the properties of native cartilage extracellular matrix (ECM) that aids in vitro cartilage formation. The CHAG scaffolds had pore size ranging from 75 to 300 µm and the degradation of 18% over 6 months in PBS. L929 cells and Human Wharton's Jelly‐Mesenchymal Stem Cells (HWJ‐MSCs) attached well and grew in the CHAG scaffolds. HWJ‐MSCs seeded on CHAG scaffolds and cultured in chondrogenic medium were able to differentiate into chondrogenic lineage. Simultaneous supplementation of growth factors (BMP‐2, TGF‐β3) significantly enhanced chondrogenesis and neo ECM synthesis. CHAG scaffolds seeded with HWJ‐MSCs cultured in chondrogenic media supplemented with both BMP‐2 and TGF‐β3 produced 12.71 ± 1.0 µg GAG/µg DNA compared to the one which received no or either of the growth factors. Our findings suggest that CHAG scaffolds could be used as a biomaterial scaffold for cell mediated repair approaches based on HWJ‐MSCs for articular cartilage. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1845–1855, 2017.
Solvent‐free method for the determination of lignin‐derived phenols in sediments
Authors: Pinto Mayara , Frena Morgana , dos Santos Madureira Luiz Augusto
Published: March 2017

A solvent‐free method that uses headspace solid‐phase microextraction and gas chromatography with flame ionization detection is proposed for the determination of lignin‐derived phenols in sediments. The extraction and derivatization conditions for the simultaneous analysis of acetosyringone, acetovanillone, syringaldehyde, vanillin, ferulic acid, syringic acid, vanillic acid, p‐hydroxybenzoic acid, and p‐coumaric acid were optimized using a central composite design. After optimization, the best results were obtained with the following conditions: exposure of the polyacrylate fiber to the headspace with 60 μL of N,O‐bis(trimethylsilyl)trifluoroacetamide as a derivatizing agent for 15 min and then extraction in the headspace of 100 mg of sediment (previously spiked with lignin‐derived phenols) for 35 min. The accuracy of the method was estimated based on recovery tests at two concentration levels and by comparison with a high‐performance liquid chromatography method reported in the literature. Based on the t‐test with a confidence level of 95%, no statistical differences were observed. The detection and quantification limits for the target compounds varied according to their characteristics: values at the microgram per gram level for nonacid compounds and milligram per gram level for phenolic acids, due to the lower volatility of the derivatives.
Surface‐imprinted microspheres prepared by a template‐oriented method for the chiral separation of amlodipine
Authors: Lai Shenzhi , Ouyang Xiaoli , Cai Changqun , Xu Wensheng , Chen Chunyan , Chen Xiaoming
Published: March 2017

The surface imprinting technique has been developed to overcome the mass‐transfer difficulty, but the utilization ratio of template molecules in the imprinting procedure still remains a challengeable task to be improved. In this work, specifically designed surface‐imprinted microspheres were prepared by a template‐oriented method for enantioseparation of amlodipine besylate. Submicron mesoporous silica microspheres were surface‐modified with double bonds, followed by polymerizing methacrylic acid to generate carboxyl modified mesoporous silica microspheres (PMAA@SiO2). Afterwards, PMAA@SiO2 was densely adsorbed with (S)‐amlodipine molecules to immobilize template molecules through multiple hydrogen bonding interactions. Then surface molecular imprinting was carried out by cross‐linking the carboxyl group of PMAA@SiO2 with ethylene glycol diglycidyl ether. The surface‐imprinted microspheres showed fast binding kinetics of only 20 min for equilibrium adsorption, and the saturation adsorption capacity reached 137 mg/g. The imprinted materials displayed appreciable chiral separation ability when used as column chromatography for enantioseparation of amlodipine from amlodipine besylate, and the enantiomeric excess of (S)‐amlodipine reached 13.8% with only 2.3 cm column length by no extra chiral additives. Besides, the imprinted materials exhibited excellent reusability, and this allows the potential application for amplification production of amlodipine enantiomer.
Increasing the Impact of Wikis on Project Performance: Fine‐tuning Functional Quality and Knowledge Sharing
Authors: Nabelsi Véronique , Gagnon Stéphane , Brochot Damien
Published: March 2017

Project managers have been among the first to adopt wikis in the workplace. Their impact on project performance in general has been documented, but we believe that there is still much room for improvement. We addressed this issue by performing an in‐depth empirical study of wiki use in IT projects within a large public sector organization. We found that performance is significantly impacted by the quality of a wiki, but also tested other factors that may help fine‐tune a wiki's capabilities: the knowledge sharing context and the distinctive use of wikis to manage project documentations, while fully exploiting its functionality. Copyright © 2017 John Wiley & Sons, Ltd.
Striatal activation by optogenetics induces dyskinesias in the 6‐hydroxydopamine rat model of Parkinson disease
Authors: F. Hernández Ledia , Castela Ivan , Ruiz‐DeDiego Irene , Obeso Jose A. , Moratalla Rosario
Published: March 2017

Background: Long‐term levodopa (l‐dopa) treatment is associated with the development of l‐dopa–induced dyskinesias in the majority of patients with Parkinson disease (PD). The etiopathogonesis and mechanisms underlying l‐dopa–induced dyskinesias are not well understood.

Methods: We used striatal optogenetic stimulation to induce dyskinesias in a hemiparkinsonian model of PD in rats. Striatal dopamine depletion was induced unilaterally by 6‐hydroxydopamine injection into the medial forebrain bundle. For the optogenetic manipulation, we injected adeno‐associated virus particles expressing channelrhodopsin to stimulate striatal medium spiny neurons with a laser source.

Results: Simultaneous optical activation of medium spiny neurons of the direct and indirect striatal pathways in the 6‐hydroxydopamine lesion but l‐dopa naïve rats induced involuntary movements similar to l‐dopa–induced dyskinesias, labeled here as optodyskinesias. Noticeably, optodyskinesias were facilitated by l‐dopa in animals that did not respond initially to the laser stimulation. In general, optodyskinesias lasted while the laser stimulus was applied, but in some instances remained ongoing for a few seconds after the laser was off. Postmortem tissue analysis revealed increased FosB expression, a molecular marker of l‐dopa–induced dyskinesias, primarily in medium spiny neurons of the direct pathway in the dopamine‐depleted hemisphere.

Conclusion: Selective optogenetic activation of the dorsolateral striatum elicits dyskinesias in the 6‐hydroxydopamine rat model of PD. This effect was associated with a preferential activation of the direct striato‐nigral pathway. These results potentially open new avenues in the understanding of mechanisms involved in l‐dopa–induced dyskinesias. © 2017 International Parkinson and Movement Disorder Society
Assessment of the modulation effect of rainfall on solar radiation availability at the Earth's surface
Authors: Díaz‐Torres J. J. , Hernández‐Mena L. , Murillo‐Tovar M. A. , León‐Becerril E. , López‐López A. , Suárez‐Plascencia C. , Aviña‐Rodriguez E. , Barradas‐Gimate A. , Ojeda‐Castillo V.
Published: March 2017

ABSTRACT

A significant proportion of the solar irradiance that reaches the Earth's surface is normally attenuated by atmospheric properties and overcast conditions related to the rainy season. The Solar Analyst (SA) model, irradiance and long term precipitation data were used to assess this relationship in Guadalajara, Mexico. A spatial analysis based on morphological and statistical criteria increased the model's certainty. The SA model explains 95.4% of the irradiation variability observed on the ground, with average uncertainties of 3.7% during clear sky conditions in the dry season and 4.4% on sunny days in the wet season. The meteorological data analysis shows that total precipitation in 2014 had an atypical temporal distribution and was slightly lower (12.6%) than the average from 1991 to 2012. A deficit of 39% in precipitation compared to the long term average was found in the first half of the season, which was later partially compensated. This deficit was interpreted as a temporary delay in high values of precipitation. Based on the potential average irradiation from the SA model and field observations, it can be concluded that overcast conditions related to rainfall through 2014 attenuated approximately 28.5% of the incoming solar energy. Taking the global energy balance into account, this fraction was higher in comparison to the energy proportion reflected by the cloud's albedo (ca 23%). These results suggest that both the high proportion of energy attenuated and atypical weather conditions may be local effects of large‐scale phenomena such as the El Niño‐Southern Oscillation.
Evaluating the performance of two global ensemble forecasting systems in predicting rainfall over India during the southwest monsoons
Authors: Dube Anumeha , Ashrit Raghavendra , Singh Harvir , Arora Kopal , Iyengar Gopal , Rajagopal E. N.
Published: March 2017

Ensemble prediction systems help in quantifying the inherent uncertainties in numerical weather prediction models. Verification of forecasts is essential, in order to monitor and improve forecast quality. Also, verification can be used to compare the capabilities of different numerical weather prediction models in predicting the weather. This study deals with a comparison of probabilistic rainfall forecasts obtained from the National Centre for Medium Range Weather Forecasting (NCMRWF) Global Ensemble Forecast System (NGEFS) and the UK Met Office Global and Regional Ensemble Prediction System (MOGREPS) for four monsoon seasons, June–September 2012–2015. Verification is done based on the Brier score, the Brier skill score, the reliability diagram, the relative operating characteristic (ROC) curve and the area under the ROC curve (AROC). The NMSG (India Meteorological Department NCMRWF merged satellite and gauge) observation dataset is used for verification.

The Brier score values for verification of the MOGREPS are lower by approximately 6–14% across all rainfall thresholds and lead times, indicating that these forecasts match better with observations than the NGEFS. This is further reiterated by Brier skill score values of MOGREPS forecasts which are approximately 13–47% higher than the NGEFS. Furthermore, the reliability diagram shows that forecast probabilities are closer to observed frequencies for the MOGREPS than the NGEFS. The AROC for the MOGREPS is also higher than for the NGEFS, hence indicating a better skill of the MOGREPS. From this study, it can be concluded that the MOGREPS showed a better capability in predicting rainfall during the southwest monsoons of 2012–2015 over the Indian region compared to the NGEFS.
Identification of transcription factors potentially involved in human adipogenesis in vitro
Authors: Ambele Melvin Anyasi , Pepper Michael Sean
Published: March 2017

Background

Increased adiposity in humans leads to obesity, which is a major risk factor for cardiovascular disease, type 2 diabetes, and cancer. We previously conducted an extensive unbiased in vitro transcriptomic analysis of adipogenesis, using human adipose‐derived stromal cells (ASCs). Here, we have applied computational methods to these data to identify transcription factors (TFs) that constitute the upstream gene regulatory networks potentially, driving adipocyte formation in human ASCs.

Methods

We used Affymetrix Transcription Analysis Console™ v3.0 for calculating differentially expressed genes. MATCH™ and F‐MATCH™ algorithms for TF identification. STRING v10 to predict protein–protein interactions between TFs.

Results

A number of TFs that were reported to have a significant role in adipogenesis, as well as novel TFs that have not previously been described in this context, were identified. Thus, 32 upstream TFs were identified, with most belonging to the C2H2‐type zinc finger and HOX families, which are potentially involved in regulating most of the differentially expressed genes observed during adipocyte differentiation. Furthermore, 17 important upstream TFs were found to have increased regulatory effects on their downstream target genes and were consistently up‐regulated during the differentiation process. A strong hypothetical functional interaction was observed among these TFs, which supports their common role in the downstream regulation of gene expression during adipogenesis.

Conclusion

Our results support several previous findings on TFs involved in adipogenesis and thereby validate the comprehensive and systematic in silico approach described in this study. In silico analysis also allowed for the identification of novel regulators of adipocyte differentiation.
Highly refractive polyimides containing pyridine and sulfur units: synthesis and thermal, mechanical, solubility and optical properties
Authors: Guan Yue , Dong Weibing , Wang Che , Shang Dejing
Published: March 2017

Two series of isomers containing pyridine and sulfur unit aromatic diamine monomers, 4,4′‐bis(5‐amino‐2‐pyridinylsulfanyl)diphenyl sulfide (2a), 4,4′‐bis(6‐amino‐3‐pyridinylsulfanyl)diphenyl sulfide (2b) and 4,4′‐bis(5‐amino‐6‐methyl‐2‐pyridinylsulfanyl)diphenyl sulfide (2c), 4,4′‐bis(5‐amino‐4‐methyl‐2‐pyridinylsulfanyl)diphenyl sulfide (2d), were designed and synthesized. Aimed at clarifying the structure–property relationships of pyridine‐ and sulfur‐containing high refractive polymers, 2a was polymerized with various dianhydrides to prepare polyimides PI‐1−PI‐7 and 2b, 2c, 2d were reacted with 4,4′‐[p‐thiobis(phenylenesulfanyl)]diphthalic anhydride to prepare polyimides PI‐8−PI‐10. The polyimides showed excellent optical properties with average refractive indices ranging from 1.7006 to 1.7620 and birefringence as low as 0.0056. Meanwhile, comparative studies on their properties including solubility, thermal and mechanical, and optical transparency properties were performed. Some property differences of the isomers caused by the sequence changes were found. © 2017 Society of Chemical Industry
Targeted label‐free quantification of interleukin‐8 in PMA‐activated U937 cell secretome by nanoLC‐ESI‐MS/MS‐sSRM
Authors: Emirbayer Pelin Esma , Gerer Kerstin F. , Hoyer Stefanie , Pischetsrieder Monika
Published: March 2017

Monocytes are a part of the innate immune system. Their differentiation into macrophages changes their cellular proteome and secretome. Particularly secretome components such as cytokines are crucial for immune response and inflammation in many diseases. Differentiation of human lymphoma cell line U937 can be triggered by phorbol 12‐myristate 13‐acetate (PMA). Screening of the cytokine release in U937 upon PMA stimulation by cytometric bead array almost exclusively showed interleukin‐8 (IL‐8). Next, a label‐free nanoLC‐ESI‐MS/MS‐sSRM method for quantification of IL‐8 in the cell secretome was established and applied to monitor the time kinetics of PMA treatment in different concentrations. Targeted secretome analysis was achieved by scheduled SRM‐MS using one proteotypic peptide as precursor ion and four mass transitions. Label‐free quantification was performed by external calibration using IL‐8 standard. Validation results indicated that the method was suited for the quantification of IL‐8 in the secretome. The maximal IL‐8 release of 62.4 ng/mL was observed after incubating cells treated by 50 ng/mL PMA for 48 h. The method can now be used for quantification of IL‐8 release from different cells under various conditions. Furthermore, it can be easily expanded to other secreted proteins detected by untargeted screening methods.
A quantum chemical study on the OH radical quenching by natural antioxidant fisetin
Authors: Bayat Ahmad , Fattahi Alireza
Published: March 2017

In this work, the antioxidant ability of fisetin was explored toward hydroxyl (•OH) radical in aqueous and lipid solution using density functional level of theory. Different reaction mechanisms have been studied: hydrogen atom transfer, single electron transfer followed by proton transfer, and radical adduct formation, and sequential proton loss electron transfer. Rate constants for all possible reaction sites have been calculated using conventional transition state theory in conjunction with the Collins‐Kimball theory. Branching ratios for the different channels of reaction are reported for the first time. Results show that the reactivity of fisetin toward hydroxyl (•OH) radical takes place almost exclusively by radical adduct formation regardless of the polarity of the environment. Also, the single‐electron transfer process seems to be thermodynamically unfavorable in both media.