bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fabrication and characterization of sulfonated polybenzimidazole/sulfonated imidized graphene oxide hybrid membranes for high temperature proton exchange membrane fuel cells
Authors: Imran Muhammad Asif , He Gaohong , Wu Xuemei , Yan Xiaoming , Li Tiantian , Khan Abdul‐Sammed 
Published: May 2019

ABSTRACTThe sulfonated polybenzimidazole (sPBI)/sulfonated imidized graphene oxide (SIGO) was evaluated to be a potential candidate for high temperature proton exchange membranes fuel cells (HT‐PEMFCs). Multifunctionalized covalently bonded SIGO is incorporated in sPBI matrix to resolve the drawbacks such as low proton conductivity, poor water uptake, and ion‐exchange capacity (IEC) of sPBI polymer, synthesized by direct polycondensation in phosphoric acid for the application of proton exchange membranes. Strong hydrogen bonding among multifunctional groups established a neighborhood of interconnected hydrophobic graphene sheets and organic polymer chains. It provides hydrophobic–hydrophilic phase separation and facile proton hopping architecture. The optimized sPBI/SIGO (15 wt %) revealed 2.45 meq g−1 IEC; 5.81 mS cm−1 proton conductivity [120 °C and 10% relative humidity (RH)] and 2.45% bound water content. The maximum power density of the sPBI/SIGO‐15 membrane was 0.40 W cm−2 at 160 °C (5% RH) and ambient pressure with stoichiometric feed of H2/air. This recommends that sPBI/SIGO composite membranes are compatible candidate for HT‐PEMFCs. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47892.
High antibacterial performance of electrospinning silk fibroin/gelatin film modified with graphene oxide‐sliver nanoparticles
Authors: Zhang Rui , Han Qiong , Li Yu , Cai Youfeng , Zhu Xuyang , Zhang Tongqing , Liu Yi 
Published: May 2019

ABSTRACTIn this study, graphene oxide‐sliver nanoparticle (GO‐AgNP) composite was synthesized in situ with GO as the raw material. Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy, and scanning electron microscopy were used to characterize the composite, the spherical Ag particles with a diameter of about 36 nm were well deposited on the surface of GO nanosheets without serious agglomeration, and the antibacterial properties of the composites were also tested. Moreover, the silk fibroin (SF)/gelatin (GT) electrospun nanofiber film was prepared by electrospinning, and the structure of the SF nanofiber film was observed using a Fourier transform infrared spectrometer, X‐ray diffractometer, and scanning electron microscope. The TGA curves indicated that the total weight loss rate of SF nanofibers at 400°C was significantly higher than that of SF/GT composite nanofibers (74.72% for pure SF, 62.37% for SF/GT nanocomposites). Finally, the GO‐AgNP composite was combined with electrospinning SF film, which resulted in the decrease in surface roughness from 393.5 ± 123.7 nm to 109.9 ± 24.43 nm and the decrease in contact angle from 82.48° to 54.78°. Besides, the GO‐AgNP composites enhanced the antibacterial performance of SF film greatly, which was conducive to its application in biological tissue engineering. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47904.
Electrically conductive polystyrene nanocomposites incorporated with aspect ratio‐controlled silver nanowires
Authors: Kim Jung Mock , Jang Keon‐Soo , Lee Seong Jae 
Published: May 2019

ABSTRACTPolymer nanocomposites consisting of electrically conductive nanofillers with high aspect ratios are widely utilized for high‐performance applications such as sensors and electronics. Silver nanowires (AgNWs) synthesized through polyol reduction have been reported to show excellent electrical conductivity, hydrophilicity, and high aspect ratios. In this study, the influence of the aspect ratios of the AgNWs on the rheological and electrical properties of the fabricated polystyrene (PS)/AgNW nanocomposites was chiefly investigated. The nanocomposites were made by combining a dispersion of AgNWs with a suspension of PS particles, followed by freeze‐drying the PS/AgNW mixture harnessing the latex technology. Scanning electron microscopy, UV–Vis spectroscopy, and thermogravimetric analysis were performed on the nanocomposites to investigate the morphological, optical, and thermal properties, respectively; in addition, X‐ray photoelectron spectroscopy was performed to examine the hydrophilic polymer poly(vinylpyrrolidone)‐capped AgNW surfaces. The rheological behavior of the nanocomposites changed from liquid‐like to solid‐like after the addition of AgNWs with high aspect ratios. The electrical percolation threshold of the AgNWs in the nanocomposites was determined by the aspect ratio of the nanofiller rather than by its length. Thus, the various properties of the PS/AgNW nanocomposites could be tuned by tailoring the aspect ratios of the AgNWs. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47927.
Toll/IMD signal pathways mediate cellular immune responses via induction of intracellular PLA2 expression
Authors: Sajjadian Seyede Minoo , Vatanparast Mohammad , Kim Yonggyun 
Published: May 2019

AbstractPhospholipase A2 (PLA2) hydrolyzes fatty acids from phospholipids at the sn‐2 position. Two intracellular PLA2s, iPLA2A and iPLA2B, have been found in Spodoptera exigua. Both are calcium‐independent cellular PLA2. Their orthologs have been found in other insects. These two iPLA2s are different in ankyrin motif of N terminal region. The objective of this study was to determine whether Toll/immune deficiency (IMD) signal pathways could mediate cellular immune responses via induction of iPLA2 expression. Both iPLA
2s were expressed in all developmental stages of S. exigua, showing the highest expression in the adult stage. During larval stage, hemocyte is the main tissue showing expression of these iPLA2s. Both iPLA2s exhibited similar expression patterns after immune challenge with different microbial pathogens such as virus, bacteria, and fungi. Promoter component analysis of orthologs encoded in S. frugiperda indicated nuclear factor‐κB‐ and Relish‐responsible elements on their promoters, suggesting their expression in S. exigua under Toll/IMD immune signaling pathways. RNA interference (RNAi) of MyD88 or Pelle under Toll pathway suppressed inducible expression levels of both iPLA2s in response to Gram‐positive bacteria containing Lys‐type peptidoglycan or fungal infection. In contrast, RNAi against Relish under IMD pathway suppressed both iPLA2s in response to infection with Gram‐negative bacteria. Under RNAi conditions, hemocytes significantly lost cellular immune response measured by nodule formation. However, addition of arachidonic acid (a catalytic product of PLA2) rescued such immunosuppression. These results suggest that Toll/IMD signal pathways can mediate cellular immune responses via eicosanoid signaling by inducing iPLA2 expression.
Product solubility control in cellooligosaccharide production by coupled cellobiose and cellodextrin phosphorylase
Authors: Zhong Chao , Luley‐Goedl Christiane , Nidetzky Bernd 
Published: May 2019

AbstractSoluble cellodextrins (linear β‐1,4‐d‐gluco‐oligosaccharides) have interesting applications as ingredients for human and animal nutrition. Their bottom‐up synthesis from glucose is promising for bulk production, but to ensure a completely water‐soluble product via degree of polymerization (DP) control (DP ≤ 6) is challenging. Here, we show biocatalytic production of cellodextrins with DP centered at 3 to 6 (~96 wt.% of total product) using coupled cellobiose and cellodextrin phosphorylase. The cascade reaction, wherein glucose was elongated sequentially from α‐d‐glucose 1‐phosphate (αGlc1‐P), required optimization and control at two main points. First, kinetic and thermodynamic restrictions upon αGlc1‐P utilization (200 mM; 45°C, pH 7.0) were effectively overcome (53% → ≥90% conversion after 10 hrs of reaction) by in situ removal of the phosphate released via precipitation with Mg2+. Second, the product DP was controlled by the molar ratio of glucose/αGlc1‐P (∼0.25; 50 mM glucose) used in the reaction. In optimized conversion, soluble cellodextrins in a total product concentration of 36 g/L were obtained through efficient utilization of the substrates used (glucose: 98%; αGlc1‐P: ∼80%) after 1 hr of reaction. We also showed that, by keeping the glucose concentration low (i.e., 1–10 mM; 200 mM αGlc1‐P), the reaction was shifted completely towards insoluble product formation (DP ∼9–10). In summary, this study provides the basis for an efficient and product DP‐controlled biocatalytic synthesis of cellodextrins from expedient substrates.
Forecasting and control of lactate bifurcation in Chinese hamster ovary cell culture processes
Authors: Schmitt John , Downey Brandon , Beller Justin , Russell Brian , Quach Anthony , Lyon David , Curran Meredith , Mulukutla Bhanu Chandra , Chu Chia 
Published: May 2019

AbstractBiomanufacturing exhibits inherent variability that can lead to variation in performance attributes and batch failure. To help ensure process consistency and product quality the development of predictive models and integrated control strategies is a promising approach. In this study, a feedback controller was developed to limit excessive lactate production, a widespread metabolic phenomenon that is negatively associated with culture performance and product quality. The controller was developed by applying machine learning strategies to historical process development data, resulting in a forecast model that could identify whether a run would result in lactate consumption or accumulation. In addition, this exercise identified a correlation between increased amino acid consumption and low observed lactate production leading to the mechanistic hypothesis that there is a deficiency in the link between glycolysis and the tricarboxylic acid cycle. Using the correlative process parameters to build mechanistic insight and applying this to predictive models of lactate concentration, a dynamic model predictive controller (MPC) for lactate was designed. This MPC was implemented experimentally on a process known to exhibit high lactate accumulation and successfully drove the cell cultures towards a lactate consuming state. In addition, an increase in specific titer productivity was observed when compared with non‐MPC controlled reactors.
The nature and extent of corporate social responsibility disclosure in Tanzania
Authors: Kikwiye Ibrahim Ramadhani 
Published: May 2019

AbstractThe study determined the nature and extent of corporate social responsibility (CSR) disclosures in the annual reports in Tanzania. The documentary analysis of the annual reports of 15 listed companies on the Dar Es Salam stock exchange market was undertaken from 2000 to 2014. The data were analysed using content analysis to determine the patterns and contents of information disclosed. The findings indicate that disclosure of CSR activities in the narrative section of the annual report is pleasing. Good reports disclosed social and environmental protection, education, health, and water supply to the stakeholders accompanied with monetary values. Other disclosures included contributions in sports and culture, empowerment of women and youth, community, employees, and human rights. However, some companies had unsystematic reporting and less monetary values to support their recipients. The study recommends the stock exchange and the accounting body to provide disclosure guidelines to improve the form and contents of reporting. Future research can be directed to other disclosure means such as websites, stand‐alone reports, and press releases of both listed and unlisted companies.
Does gender diversity matter for green innovation?
Authors: He Xiaoping , Jiang Shuo 
Published: May 2019

AbstractThis study empirically investigated the relationship between board gender diversity and firm's green innovation, using panel data of public companies of China's manufacturing. Green product innovation was assessed by “green” patents and green process innovation assessed by environmental management certification. The endogeneity problem that resulted from self‐selection of gender diversity was addressed by means of extended probit regressions with an instrumental variable, and the instrumental variable was elaborately constructed based on changes in directorships. The findings show that occurrence of green innovation at the firm‐level is systematically related to female board representation. Specifically, women can exert a sizable and positive effect on green innovation, once they enjoy at least two seats on the boards; a further increase in representation of women on the boards can increase the likelihood of green product innovation rather than the likelihood of green process innovation. These results were robust to various regression specifications and alternative samples. The study provides empirical evidence that women at the top management can play a positive role in developing firm's active environmental strategies, and the conclusions are of practical implications for improving corporate governance along the environmental dimension.
Exosomal cyclophilin A as a novel noninvasive biomarker for Epstein‐Barr virus associated nasopharyngeal carcinoma
Authors: Liu Lingzhi , Zuo Lielian , Yang Jing , Xin Shuyu , Zhang Jing , Zhou Jianhua , Li Guiyuan , Tang Jinyong , Lu Jianhong 
Published: May 2019

AbstractExosomes have emerged as novel vehicles for proteins and other contents in cancer progression. Cyclophilin A (CYPA) is a pivotal member of immunophilin family. Whether CYPA can be detected in sera of nasopharyngeal carcinoma (NPC) patients remains to be explored. Epstein‐Barr virus (EBV) is the first identified human tumor virus and is a causative agent of NPC. The antibody of EBV capsid antigen immunoglobulin A (EBV‐VCA‐IgA) is a known biomarker of NPC, with a proportion of no more than 70% being detected positively. Hence, novel biomarkers need to be discovered for early diagnosis, prognosis, and monitoring of EBV‐associated NPC. A total of 110 NPC and 36 normal control serum samples were collected. Exosomes from these samples were extracted. The mRNA and protein expression levels of the above samples were validated by reverse transcription –quantitative polymerase chain reaction, Western blotting, or enzyme‐linked immunosorbent assay (ELISA). Finally, the results demonstrated that both the serum and exosomal CYPA levels of NPC patients were significantly higher than that of normal cases. In addition, exosomal CYPA had a much higher level than that in the whole sera. The positive rate of EBV‐VCA‐IgA antibody was 68.2% in NPC sera, and noticeably, among the cases with EBV‐VCA‐IgA negative, 80% of them presented high levels of CYPA above the standard (cutoff value). In particular, CYPA in exosomes was uniformly with higher significance than that in whole sera. Combined analysis of CYPA protein and EBV‐VCA‐IgA antibody showed a greatly higher discriminatory ability in diagnosis of NPC. Moreover, exosomal CYPA level had a positive correlation with that of the EBV‐encoded latent membrane protein 1 (LMP1) in exosomes. EBV‐positive cancer cells secreted significantly higher levels of exosomal CYPA. This study established the utility of circulating exosomal CYPA as a potential noninvasive diagnostic biomarker for EBV‐associated NPC.
Effects of RhoC downregulation on the angiogenesis characteristics of myeloma vascular endothelial cells
Authors: Zhao Zhihua , Liu Kai , Tian Xiangyu , Sun Miaomiao , Wei Na , Zhu Xiaoyan , Yang Hongmei , Wang Tong , Jiang Guozhong , Chen Kuisheng 
Published: May 2019

AbstractBackgroundTumor angiogenesis plays an important role in disease progression, and RhoC has been previously found to be expressed in vascular endothelial cells (VECs); however, its role in tumor angiogenesis requires clarification. This study aimed to explore the effects of RhoC downregulation on the cytoskeleton, pseudopod formation, migration ability, and canalization capacity of myeloma vascular endothelial cells (MVECs) in vitro.Materials and methodsThe expression of RhoC in MVECs and human umbilical vein endothelial cells (HUVECs) was knocked down by shRNA, and the expression levels of RhoC mRNA were detected by quantitative reverse transcription polymerase chain reaction (qRT‐PCR). The cytoskeletal changes and pseudopods were observed by laser scanning confocal and scanning electron microscopy; VECs were incubated in two‐dimensional Matrigel and three‐dimensional microcarriers to observe tube‐like structures and budding status, respectively. The protein expression of RhoC, phosphorylation of mitogen‐activated protein kinase (p‐MAPK), and Rho‐associated coiled‐coil kinase (ROCK) was determined by Western blotting. The expression of RhoC in VECs was downregulated by RhoC shRNA, thereby decreasing the number of pseudopods, two‐dimensional tube‐like structures, and buds.ResultsWhen RhoC was downregulated, the expression levels of ROCK and phosphorylation of MAPK were both decreased (P < 0.05). Moreover, the expression levels of RhoC and phosphorylation of MAPK and three‐dimensional budding numbers were higher in MVECs than in HUVECs (P < 0.05). The downregulation of RhoC expression in MVECs and HUVECs inhibited pseudopod formation, migration, canalization ability, and angiogenesis (P < 0.05).ConclusionOur data indicated that MVECs and HUVECs were well suited for angiogenesis research, but the former cell type was shown to be more advantageous in terms of budding numbers. RhoC plays a pivotal role in MVECs angiogenesis, and the downregulation of RhoC expression could inhibit angiogenesis via the RhoC/MAPK and RhoC/ROCK signaling pathways.
Metal‐Free and Heterogeneous Photocatalytic Reduction of 4‐Nitroaniline by a Poly(Ethylene Glycol)‐Supported Eosin Dye under Visible‐Light Exposure
Authors: Chibac Andreea L. , Melinte Violeta , Brezová Vlasta , Renard Estelle , Brosseau Arnaud , Langlois Valerie , Versace Davy‐Louis 
Published: May 2019

AbstractA new feasible approach for the photoreduction of a chemical pollutant, 4‐nitroaniline, to p‐phenylenediamine was developed. We highlighted the crucial roles of a polymer backbone and the atmosphere for the efficient heterogeneous reduction of 4‐nitroaniline. The novel synthesized poly(ethylene glycol)‐derived film containing immobilized eosin dye revealed a high photoreduction rate of 4‐nitroaniline. According to laser flash photolysis results the first step of this photoinduced process represents a single electron transfer from eosin radical anion to the 4‐nitroaniline to form a nitroaniline radical anion. The in‐situ electron paramagnetic resonance spin‐trapping experiments evidenced the generation of superoxide radical anion serving as catalyst in the p‐phenylenediamine production according to a photoreduction process. The main roles play by poly(ethylene glycol) matrix as efficient reducing agent and hydrogen‐donor molecule was also pointed out. A mechanism was proposed to explain the heterogeneous photoreduction of 4‐nitroaniline to p‐phenylenediamine in the presence of eosin dye‐based poly(ethylene glycol) system under air.
Proper Orthogonal Decomposition and Statistical Analysis of 2D Confined Impinging Jets Chaotic Flow
Authors: Torres Pedro , Goncalves Nelson D. , Fonte Claudio P. , Dias Madalena M. , Lopes José Carlos B. , Liné Alain , Santos Ricardo J. 
Published: May 2019

AbstractProper orthogonal decomposition (POD) is shown to be a statistical operation that identifies the main characteristics of chaotic flows and separates them into a few modes. The dynamic chaotic flow is obtained from two‐dimensional (2D) computational fluid dynamics simulations, for different Reynolds numbers, of a confined impinging jets mixer. POD enables reconstruction of the dynamic flow from a few modes that are related to coherent flow structures. The POD flow reconstruction enables a large compression of the flow data set. The decomposition of the flow field into orthogonal modes related to coherent structures provides direct insight into the mixing dynamics and scales which are not accessible from flow dynamics statistic quantities, which were introduced in the context of turbulence and are here applied to chaotic flow.
Anomeric 5‐Aza‐7‐deaza‐2′‐deoxyguanosines in Silver‐Ion‐Mediated Homo and Hybrid Base Pairs: Impact of Mismatch Structure, Helical Environment, and Nucleobase Substituents on DNA Stability
Authors: Zhou Xinglong , Kondhare Dasharath , Leonard Peter , Seela Frank 
Published: May 2019

AbstractNucleoside configuration (α‐d vs. β‐d), nucleobase substituents, and the helical DNA environment of silver‐mediated 5‐aza‐7‐deazaguanine‐cytosine base pairs have a strong impact on DNA stability. This has been demonstrated by investigations on oligonucleotide duplexes with silver‐mediated base pairs of α‐d and β‐d anomeric 5‐aza‐7‐deaza‐2′‐deoxyguanosines and anomeric 2′‐deoxycytidines incorporated in 12‐mer duplexes. To this end, a new synthetic protocol has been developed to access the pure anomers of 5‐aza‐7‐deaza‐2′‐deoxyguanosine by glycosylation of either the protected nucleobase or its salt followed by separation of the glycosylation products by crystallization and chromatography. Thermal stability measurements were performed on duplexes with α‐d/α‐d and β‐d/β‐d homo base pairs or α‐d/β‐d and β‐d/α‐d hybrid pairs within two sequence environments, positions 6 or 7, of oligonucleotide duplexes. The respective Tm stability increases observed after silver ion addition differ significantly. Homo base pairs with β‐d/β‐d or α‐d/α‐d nucleoside combinations are more stable than α‐d/β‐d hybrid base pairs. The positional switch of silver‐ion‐mediated base pairs has a significant impact on stability. Nucleobase substituents introduced at the 5‐position of the dC site of silver‐mediated base pairs affect base pair stability to a minor extent. Our investigation might lead to applications in the construction of bioinspired nanodevices, in DNA diagnostics, or metal‐DNA hybrid materials.
Enantioseparation of flurbiprofen enantiomers using chiral ionic liquids by liquid‐liquid extraction
Authors: Cui Xing , Ding Qi , Shan Ruo‐Ni , He Chao‐Hong , Wu Ke‐Jun 
Published: May 2019

AbstractFlurbiprofen is a kind of nonsteroidal anti‐inflammatory drug, which has been widely used in clinic for treatment of rheumatoid arthritis and osteoarthritis. It has been reported that S‐flurbiprofen shows good performance on clinic anti‐inflammatory treatment, while R‐enantiomer almost has no pharmacological activities. It has important practical values to obtain optically pure S‐flurbiprofen. In this work, chiral ionic liquids, which have good structural designability and chiral recognize ability, were selected as the extraction selector by the assistance of quantum chemistry calculations. The distribution behaviors of flurbiprofen enantiomers were investigated in the extraction system, which was composed of organic solvent and aqueous phase containing chiral ionic liquid. The results show that maximum enantioselectivity up to 1.20 was attained at pH 2.0, 25°C using 1,2‐dichloroethane as organic solvent, 1‐butyl‐3‐methylimidazole L‐tryptophan ([Bmim][L‐trp]) as chiral selector. The racemic flurbiprofen initial concentration was 0.2 mmol L−1, and [Bmim][L‐trp] concentration was 0.02 mol L−1. Furthermore, the recycle of chiral ionic liquids has been achieved by reverse extraction process of the aqueous phase with chiral selector, which is significant for industrial application of chiral ionic liquids and scale‐up of the extraction process.