bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient Production of High‐Quality Polystyrene‐Functionalized Graphene via Graphite Exfoliation in Chloroform with a Heterobifunctional Hyperbranched Polyethylene as Stabilizer
Authors: Duan Donghai , Ye Huijian , Luo Zhenggang , Han Bo , Chen Yafei , Cao Xiehong , Liu Wenxian , Zhong Mingqiang , Xu Lixin
Published: March 2019

Efficient production of high‐quality, functionalized graphene is highly desirable for large‐scale applications of graphene. Herein, a route for producing high‐quality, polystyrene (PS)‐functionalized graphene is demonstrated via graphite exfoliation in chloroform with a heterobifunctional hyperbranched polyethylene, HBPE@Py@PS, as stabilizer. The HBPE@Py@PS, possessing a pyrene‐functionalized hyperbranched polyethylene backbone and multiple PS side chains, is synthesized by combining chain walking polymerization and atom transfer radical polymerization techniques. It is confirmed that the HBPE@Py@PS can effectively promote graphite exfoliation in chloroform under sonication to render stable dispersions of high‐quality graphene, with an exfoliation efficiency high as 15% and a monolayer proportion, 61%. Meanwhile, it can irreversibly adsorb on the exfoliated graphene surface based on the π–π stacking interactions, concurrently rendering PS‐functionalized graphene that is fluorescent and highly dispersible in chloroform, with a film conductivity reaching 1100 S m−1. The as‐produced graphene may find its applications as nanofiller for various PS‐based graphene nanocomposites.
Increasing Volumetric CO2 Uptake of Hypercrosslinked Polymers through Composite Formation
Authors: Yang Yang , Pu Wanfen , Xu Xingguang , Wei Bing , Yang Yunxia , Wood Colin D.
Published: March 2019

To overcome the drawbacks of solid microporous materials for CO2 capture, this proof‐of‐concept study demonstrates a low‐cost and rapid method for producing composites consisting of hypercrosslinked polymers (HCP) with a polyethyleneimine (PEI) binder. The resulting materials capture CO2 through physical and chemical absorption simultaneously. Compared with HCP, the composites exhibit higher CO2 uptake, higher volumetric density, and improved tolerance to water which is attributed to the PEI binder.
Effect of a session of intensive exercise with ginseng supplementation on histone H3 protein methylation of skeletal muscle of nonathlete men
Authors: Naghavi moghadam Ali akbar , Shiravand Mostafa , Rezapour Sadegh , Khoshdel Alireza , Bazgir Behzad , Mardani Mahnaz
Published: March 2019

Purpose

The pressure and stress caused by some intense exercises cause changes in histone proteins and gene expression. The aim of this study was to investigate the effect of one session of intensive exercise with supplementation of ginseng, on the methylation of H3K‐36 histone protein in skeletal muscle of young nonathlete men.

Methods

After the approval by the ethics committee, 12 untrained male subjects were randomly assigned to either exercise group (six subjects) or exercise and supplement group. First, from both groups, the muscular sample was taken from the broad‐lateral muscle of the subjects. Immediately after the muscle biopsy, exercise and exercise + supplement groups completed the exercise protocol. During this period, the exercise + supplement group consumed ginseng supplementation and took placebo group. Immediately after exercise, all subjects were retested.

Results

There was no significant increase in histone H3‐k36 protein methylation in the intergroup between exercise + supplementation and exercise. There was a significant difference within the training group but there was no difference in the exercise + supplementation group.

Conclusion

The methylation caused by intense physical pressure, can be reduced by ginseng extract.
Neural Activation During Visual Attention Differs in Individuals with High versus Low Macular Pigment Density
Authors: Oliver William , Renzi‐Hammond Lisa M. , Thorne S. Anna , Clementz Brett , Miller L. Stephen , Hammond Billy R.
Published: March 2019

Scope

The neural efficiency hypothesis for lutein (L) and zeaxanthin (Z) suggests that higher levels of L+Z in the central nervous system (CNS) are predictive of stronger stimulus‐specific brain responses. Past research suggests that supplementing L+Z can improve neural processing speed and cognitive function across multiple domains, which supports this hypothesis. The purpose of this study is to determine the extent to which CNS L+Z levels predict brain responses using an attentionally taxing task.

Methods and results

Macular pigment optical density (MPOD) is measured at baseline in 85 participants ranging in age from 18–92 years. Brain activation is measured using dense array electroencephalography. Stimuli evoking the signal include a grating array of vertical bars, oscillating at four driving frequencies. Significant stimulus‐specific interactions are detected between attend condition, location, and age (p < .002) for unattended image locations, and between age and location (p < .008) for attended locations. Although no differences are found across age by MPOD, this measure is found to be predictive of neural power at parafoveal bar locations (R2 .080).

Conclusion

CNS L+Z status is related to differences in brain activation in conditions designed to stress visual attention. These differences are strongest for older subjects.
DNA Hypomethylation of GR Promoters is Associated with GR Activation and BDNF/AKT/ERK1/2‐Induced Hippocampal Neurogenesis in Mice Derived From Folic‐Acid‐Supplemented Dams
Authors: Yang Yang , Yang Shu , Liu Jie , Feng Yue , Qi Fulei , Zhao Ruqian
Published: March 2019

Scope

Glucocorticoid receptor (GR) mediates the nutritional programing of offspring performance. Maternal folic acid has been shown to regulate hippocampal neurogenesis and affect cognitive function in offspring, yet it remains unclear whether and how GR is involved in such effects.

Methods and results

Adult male mice derived from dams fed basal or folic‐acid‐supplemented diet (5 mg folic acid/kg) throughout gestation and lactation are used in this study. Maternal folic acid significantly enhances offspring learning and memory with less fear‐related behavior. Concurrently, hippocampal neurogenesis is improved with upregulation of brain‐derived neurotrophic factor and its downstream AKT/ERK1/2 signaling pathway. More GR immune‐positive cells are observed in hippocampus of folic acid group, which are in line with higher GR protein and mRNA abundances. Differential expression of GR exon 1 transcript variants is detected, which is inversely associated with modified DNA methylation on their alternate promoters.

Conclusion

The results indicate that maternal folic acid supplementation promotes hippocampal neurogenesis and improves learning and memory behavior in mouse offspring. The mechanisms involve modification of DNA methylation on GR alternate promoters and GR upregulation in the hippocampus, which is associated with activation of BDNF/AKT/ERK1/2 signaling.
A charcot‐marie‐tooth type 1B kindred associated with hemifacial spasm and trigeminal neuralgia
Authors: Caress James B. , Lewis James A. , Pinyan Clark W. , Lawson Victoria H.
Published: March 2019

Introduction: Charcot‐Marie‐Tooth (CMT) phenotypes can be distinguished by electrophysiology and genetic analysis but few can be identified by their clinical characteristics. Distinctive phenotypes are useful in identifying affected individuals and providing additional clues about the mechanism of the neuropathy. Cranial neuropathies are uncommon features of CMT, and few reports of familial hemifacial spasm (HFS) and trigeminal neuralgia (TN) have been published. Methods: Sixty‐three members of a large CMT 1B kindred were assessed for signs of peripheral neuropathy and cranial neuropathies then tested for the G163R mutation in the myelin protein zero (MPZ) gene. Results: Of 27 individuals with the G163R mutation in MPZ, 10 had HFS or TN. Co‐existing HFS and TN were found in 3 of these and 4 had bilateral HFS or TN. Conclusions: This kindred exhibits a distinct CMT phenotype characterized by the development of HFS or TN decades after clinical signs of hereditary neuropathy are manifest. Muscle Nerve, 2019
Removal of Serum Lipids and Lipid‐Derived Metabolites to Investigate Breast Cancer Cell Biology
Authors: Brovkovych Viktor , Aldrich Alyssa , Li Nasi , Atilla‐Gokcumen G. Ekin , Frasor Jonna
Published: March 2019

The use of cultured cells has been instrumental in studying biochemical, molecular, and cellular processes. The composition of serum that cells are maintained in can have a profound impact on important cellular checkpoints. Cell growth and apoptosis are analyzed in an estrogen receptor positive breast cancer cell line in the presence of serum that have been treated to remove steroids or lipids, as well‐described in the literature. It is shown that maintaining cells in the presence of charcoal‐dextran‐treated serum causes reduced growth rate, which can be reversed by the addition of estradiol. Silica‐treated‐serum also slows down cell growth and induces apoptosis. In order to investigate the role of lipids in these phenotypes, the levels of a wide range of lipids in different sera are investigated. It is shown that silica‐treatment significantly depletes phosphatidylcholines and cholesterol. It is also shown that lipogenesis is stimulated when cells are cultured with silica‐treated‐serum and this is reversed by the addition of exogenous lipids, which also restores growth rate and apoptosis. The results show that cultured cells are sensitive to different serum, most likely due to the differences in levels of structural and signaling metabolites present in their growth environment.
Risk Factors for Falls in Adults with Knee Osteoarthritis: A Systematic Review
Authors: Manlapaz Donald G. , Sole Gisela , Jayakaran Prasath , Chapple Cathy M.
Published: March 2019

Objective

To examine the evidence of risk factors for falls in adults with knee osteoarthritis (OA).

Type

Systematic Review.

Methodology

A systematic literature search was performed in 9 electronic databases from inception to July 2016. Two reviewers screened articles using set inclusion and exclusion criteria. Observational study designs that included participants with knee OA and history of falls were considered. Results reported as odds ratios, relative risks, prevalence ratios, or hazard ratios were extracted to identify the potential risk factors for falls. Included articles were assessed for methodological quality and level of evidence.

Synthesis

The electronic data search yielded 4382 studies related to falls and knee OA. A total of 11 studies were included in the review. The risk factors for falls in individuals with knee OA included impaired balance, muscle weakness, presence of comorbidities, and increasing number of symptomatic joints. The presence of knee pain was also identified as a risk factor for falls; however, the strength of evidence was rated as “conflicting” because of the inconsistency of the findings. Limited evidence was found for knee instability, impaired proprioception, and use of walking aids.

Conclusion

This review provides evidence of risk factors for falls in individuals with knee OA. Despite the limited to moderate evidence, identification of these risk factors may be valuable for both clinicians and fall prevention program developers. Further studies are warranted to determine which of these risk factors for falls are modifiable in a knee OA population.

Level of Evidence

I
The Effectiveness of Kinesiotaping, Sham Taping or Exercises Only in Lateral Epicondylitis Treatment: A Randomized Controlled Study
Authors: Giray Esra , Karali‐Bingul Duygu , Akyuz Gulseren
Published: March 2019

Background

Lateral epicondylitis is a common musculoskeletal condition presenting with pain and tenderness over the lateral epicondyle and dorsal forearm, pain and weakness in gripping and limitations in daily activities. It is proposed that kinesiotaping, a new application of adhesive taping, reduces pain and improves muscle function.

Objective

To compare efficacy of kinesiotaping, sham taping, or exercises only in the treatment of lateral epicondylitis.

Design

Double‐blind, randomized, controlled trial.

Setting

Tertiary medical center, university hospital.

Participants

Thirty patients with lateral epicondylitis for less than 12 weeks.

Methods or Interventions

Patients were randomized into three groups: kinesiotaping plus exercises (n = 10), sham taping plus exercises (n = 10), and control (exercises only) (n = 10) groups. All recipients were provided a home exercise program including strengthening and stretching exercises. In kinesiotaping and sham taping groups, tapings were performed and changed every 3–4 d for 2 weeks.

Main Outcome Measure(s)

The primary outcome was the patient‐rated tennis elbow evaluation (PRTEE). Pain visual analogue scale (VAS), grip strength, and the disabilities of the arm, shoulder and hand (QuickDASH) scales were secondary outcomes. Evaluations were done at baseline, posttreatment, and at 4 weeks after treatment. The immediate effect was also assessed by VAS and grip strength immediately after real and sham tapings.

Results

PRTEE total scores at posttreatment and at 4 weeks after treatment were statistically significantly lower in kinesiotaping plus exercises group compared to sham taping plus exercises group and exercises only group. The effects of kinesiotaping were larger than sham taping and only exercises at posttreatment (d = −1.21, d = −1.33) and at 4 weeks after treatment (d = −1.39, d = −1.34). Repeated‐measures anova showed a significant interaction between the time and the groups (F 2950 = 4849; P = .006). Significant between‐group differences were found in QuickDASH score and VAS at rest at 4 weeks after treatment, VAS at daily activity at posttreatment and 4 weeks after treatment when kinesiotaping plus exercises and sham taping plus exercises groups and kinesiotaping plus exercises and exercises only groups were compared. Real taping but not sham taping immediately led to an increase in grip strength, decrease in VAS at rest and VAS at daily activity (P = .0017, P = .041, P = .028; respectively).

Conclusions

Kinesiotaping in addition to exercises is more effective than sham taping and exercises only in improving pain in daily activities and arm disability due to lateral epicondylitis.

Level of Evidence

I
Validation of quartz crystal rheometry in the megahertz frequency regime
Authors: Delgado David E. , Sturdy Lauren F. , Burkhart Craig W. , Shull Kenneth R.
Published: March 2019

The utility of the quartz crystal microbalance (QCM) as a high‐frequency rheometer operating at 15 MHz was demonstrated. High‐frequency data obtained from a series of rubbery materials were compared with results obtained from traditional dynamic mechanical analysis (DMA) at much lower frequencies. The high‐frequency data enable meaningful shift factors to be obtained at temperatures much further above glass‐transition temperature (T
g) than would otherwise be possible, giving a more complete picture of the temperature dependence of the viscoelastic properties. The QCM can also be used to quantify mass uptake and changes in viscoelastic properties during sample oxidation. The viscoelastic response spanning the full range of behaviors from the rubber to glassy regimes was found to fit well with a six‐element model consisting of three power‐law springpot elements. One of these elements is particularly sensitive to the behavior in the transition regime where the phase angle is maximized. The value of this quantity is obtained from the maximum phase angle, which can be obtained from a temperature sweep at fixed frequency, proving a means for more detailed frequency‐dependent rheometric information to be obtained from a fixed‐frequency measurement at a range of temperatures. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 1246–1254
A methodology for overall consequence assessment in oil and gas pipeline industry
Authors: Chen Xuefeng , Wu Zongzhi , Chen Wentao , Kang Rongxue , Wang Shu , Sang Haiquan , Miao Yongchun
Published: March 2019

Quantitative risk assessment (QRA) has been widely used in the oil and gas pipeline industry. QRA mainly includes four steps, namely, hazard identification, probability calculation, consequence assessment, and risk quantification. Consequence assessment is an integral part of QRA, which aims to quantify the negative impacts when pipeline failure events take place. However, the current consequence assessment methods mainly pay attention to the determination of the influence area around accidents and to simple assimilations of the losses, ignoring the components of these losses. This leads to the deterioration of the quality of the QRA. In this article, a methodology for overall consequence assessment in the oil and gas pipeline industry is proposed. The methodology mainly involves three stages, namely, identification of the accident scenario, the determination of influence area, and the calculation of possible losses. The most important innovation spot is integrating four aspects of release accident loss into a quantitative model, to calculate a quantitative result of the loss value of a release accident. Therefore, this study can overcome the limitations of current QRA methodologies and improve the quality of QRA for oil and gas pipelines. © 2019 American Institute of Chemical Engineers Process Saf Prog, 38: e12050, 2019
Heterochiral Ala/(αMe)Aze sequential oligopeptides: Synthesis and conformational study
Authors: Drouillat Bruno , Peggion Cristina , Biondi Barbara , Wright Karen , Couty François , Crisma Marco , Formaggio Fernando , Toniolo Claudio
Published: March 2019

α‐Amino acid residues with a ϕ,ψ constrained conformation are known to significantly bias the peptide backbone 3D structure. An intriguing member of this class of compounds is (αMe)Aze, characterized by an Nα‐alkylated four‐membered ring and Cα‐methylation. We have already reported that (S)‐(αMe)Aze, when followed by (S)‐Ala in the homochiral dipeptide sequential motif ‐(S)‐(αMe)Aze‐(S)‐Ala‐, tends to generate the unprecedented γ‐bend ribbon conformation, as formation of a regular, fully intramolecularly H‐bonded γ‐helix is precluded, due to the occurrence of a tertiary amide bond every two residues. In this work, we have expanded this study to the preparation and 3D structural analysis of the heterochiral (S)‐Ala/(R)‐(αMe)Aze sequential peptides from dimer to hexamer. Our conformational results show that members of this series may fold in type‐II β‐turns or in γ‐turns depending on the experimental conditions.
Optimization of Electrical Properties of MoS2 Field‐Effect Transistors by Dipole Layer Coulombic Interaction With Trap States
Authors: Chuai Xichen , Yang Guanhua , Wei Wei , Wang Jiawei , Shi Xuewen , Lu Congyan , Zhao Ying , Su Yue , Wu Quantan , Geng Di , Lu Nianduan , Li Ling , Liu Ming
Published: March 2019

The large negative threshold voltage is one of major electrical factors hindering potential applications of MoS2 transistors in low‐power circuit systems. Here, a strategy by forming an electric dipole layer on the surface of MoS2 is presented to optimize the threshold voltage in monolayer polycrystalline MoS2 field‐effect transistors. The electric dipole in an inert non‐conjugated polymer, perfluoropolyether (PFPE), can interact with trapped electrons in the MoS2 active layer and transfer the traps from shallow into deep states, which remarkably improves the threshold voltage. Otherwise, ab initio calculation and molecular dynamics simulation are employed to investigate the transport properties of MoS2 with PFPE. The calculated results imply that localized electrons are dominantly affected by PFPE, while free electrons are irrelevant. This method with dipole layer provides a pathway to implementation of high‐performance MoS2 transistors for future electronic applications.
Memristive Devices and Networks for Brain‐Inspired Computing
Authors: Zhang Teng , Yang Ke , Xu Xiaoyan , Cai Yimao , Yang Yuchao , Huang Ru
Published: March 2019

As the era of big data approaches, conventional digital computers face increasing difficulties in performance and power efficiency due to their von Neumann architecture. As a result, there is recently a tremendous upsurge of investigations on brain‐inspired neuromorphic hardware with high parallelism and improved efficiency. Memristors are considered as promising building blocks for the realization of artificial synapses and neurons and can therefore be utilized to construct hardware neural networks. Here, a review is provided on existing approaches for the implementation of artificial synapses and neurons based on memristive devices; and the respective advantages and disadvantages of these approaches are evaluated. This is followed by a discussion of hardware accelerators and neuromorphic computing systems that exploit the parallel, in‐memory and analog characteristics of memristive crossbar arrays as well as the intrinsic dynamics of memristors. Finally, the outstanding challenges are addressed that have not yet been resolved in the present studies, and future advances are discussed that might be needed for building intelligent and energy efficient neuromorphic systems.
Direct analysis from dried blood spot card surfaces with direct probe mass spectrometry – Evaluation study
Authors: Wójtowicz Anna , Majda Alicja , Zapotoczny Szczepan , Wietecha‐Posłuszny Renata
Published: March 2019

Rationale

The Direct Probe Mass Spectrometry (DIPMS) method allows successful analysis of powders, solid and liquid samples. The potential of direct surface analysis could find further application in the examination of surfaces with good absorption properties such as Dried Blood Spot (DBS) cards that constitute a great alternative to the classical blood collection method directly from veins.

Methods

DIPMS was performed with the ionization carried out under atmospheric pressure in an Atmospheric Pressure Chemical Ionization source. Direct analysis of diazepam solutions in methanol and after their deposition onto a DBS card was conducted. Subsequently, images of the DBS cards with and without blood samples were acquired using Scanning Electron Microscopy (SEM).

Results

Direct quantitative analysis of diazepam liquid samples by DIPMS was successfully performed. Linear correlation between the concentration of diazepam and the peak intensity with a R2 coefficient of 0.937 was obtained. However, the method failed when the analysis was conducted directly from the surface of the DBS cards and no diazepam peak was observed in the mass spectrum. The SEM images confirmed the good absorption properties of DBS cards and the absence of blood components on the surface.

Conclusions

DIPMS is an excellent technique for the rapid, direct analysis of powders, solid and liquid samples; however, the potential of the method is limited when samples are deposited on surfaces with good absorption properties such as DBS cards.
Concise Review: Patency of Small-Diameter Tissue-Engineered Vascular Grafts: A Meta-Analysis of Preclinical Trials
Authors: Skovrind Ida , Harvald Eva Bang , Juul Belling Helene , Jørgensen Christian Damsgaard , Lindholt Jes Sanddal , Andersen Ditte Caroline
Published: March 2019

Several patient groups undergoing small-diameter (<6 mm) vessel bypass surgery have limited autologous vessels for use as grafts. Tissue-engineered vascular grafts (TEVG) have been suggested as an alternative, but the ideal TEVG remains to be generated, and a systematic overview and meta-analysis of clinically relevant studies is lacking. We systematically searched PubMed and Embase databases for (pre)clinical trials and identified three clinical and 68 preclinical trials ([>rabbit]; 873 TEVGs) meeting the inclusion criteria. Preclinical trials represented low to medium risk of bias, and binary logistic regression revealed that patency was significantly affected by recellularization, TEVG length, TEVG diameter, surface modification, and preconditioning. In contrast, scaffold types were less important. The patency was 63.5%, 89%, and 100% for TEVGs with a median diameter of 3 mm, 4 mm, and 5 mm, respectively. In the group of recellularized TEVGs, patency was not improved by using smooth muscle cells in addition to endothelial cells nor affected by the endothelial origin, but seems to benefit from a long-term (46–240 hours) recellularization time. Finally, data showed that median TEVG length (5 cm) and median follow-up (56 days) used in preclinical settings are relatively inadequate for direct clinical translation. In conclusion, our data imply that future studies should consider a TEVG design that at least includes endothelial recellularization and bioreactor preconditioning, and we suggest that more standard guidelines for testing and reporting TEVGs in large animals should be considered to enable interstudy comparisons and favor a robust and reproducible outcome as well as clinical translation.
Identification of Promising Biofilm Inhibitory and Cytotoxic Quinazolin‐4‐one Derivatives: Synthesis, Evaluation, Molecular Docking and ADMET Studies
Authors: Ansari Siddique A. , Deshmukh Satish U. , Patil Rajesh B. , Damale Manoj G. , Patil Rajendra H. , Alkahtani Hamad M. , Almehizia Abdulrahman A. , Al‐Tuwajiri Hanaa M. , Aleanizy Fadilah S. , Alqahtani Fulwah Y. , Pathan Shahebaaz K. , Sangshetti Jaiprakash N.
Published: March 2019

A library of 2,3‐dihydroquinazolin‐4(1H)‐one derivatives (5 a‐k) were synthesized in good yield by using 1‐Ethyl‐3‐Methylimidazolium hydrogen sulphate (10 mol %) as a catalyst and were evaluated for their anti‐biofilm, antimicrobial and cytotoxicity potential. Among the synthesized compounds, 2‐(4‐(1H‐1,2,4‐triazol‐1‐yl)phenyl)‐2,3‐dihydroquinazolin‐4(1H)‐one (5d) and 2,3‐dihydro‐2‐(2,4,6‐trimethoxyphenyl) quinazolin‐4(1H)‐one (5j) displayed better anti‐biofilm activity than fluconazole (IC50 = 40 μM) with IC50 values less than 30 μM. Compound 5d also appeared to be fungicidal against C. Albicans having MIC=33.5 μg/ml comparable with standard fluconazole (50 μg/ml). All the synthesized compounds were also evaluated for cytotoxic activity by using MTT assay against HeLa, A‐549 and MDA‐MB‐231 cell lines. The compound 5d was found to be more potent against MDA‐MB‐231 and A549 cell lines (IC50 = 11 ± 2 μM and 34±8 μM respectively) than 5‐fluorouracil (IC50 = 19 ± 3 μM and 51 ± 5 μM respectively). The compounds substituted with 6‐methyl‐4‐oxo‐4H‐chromen‐3‐yl (5a), biphenyl (5c) and 2‐hydroxy‐5‐bromophenyl (5e) were also found to be more potent against MDA‐MB‐231 cell lines (IC50 = 13 ± 3 – 14 ± 4 μM) than 5‐fluorouracil. Molecular docking simulations were also carried out using secreted aspartyl protease (SAP5), pepA enzyme of C. albicans for biofilm inhibition and EGFR tyrosine kinase for cyto‐toxicity studies. The study reveals that the compounds 5d and 5e can serve as an important lead moiety for biofilm inhibition and cyto‐toxicity against MDA‐MB‐231 and A549 cancer cell‐lines indicating their potential in the treatment of tougher fungal infections and breast and lung cancer.
Rationally Designed Functional Ni2P Nanoparticles as Co–Catalyst Modified CdS@g‐C3N4 Heterojunction for Efficient Photocatalytic Hydrogen Evolution
Authors: Wang Guorong , Jin Zhiliang
Published: March 2019

Ni2P nanoparticle contained no precious metal as co‐catalyst to touch up CdS nanorods coupling with graphitic C3N4 for H2 evolution was synthesized successfully by in‐situ fabrication approach. The preparative Ni2P‐CdS/g‐C3N4 composite catalyst exerts remarkable hydrogen production activity and exhibit good photostability in 20 hour cycles. The hydrogen evolution rate is 9.9 times as high as that of pure CdS. Morphological characterization, optical results and electrochemical test proved that special CdS/g‐C3N4 enhanced the transfer of electrons on CdS and g‐C3N4, loading Ni2P co‐catalyst further increased the synergistic effect in photocatalytic properties. Several characterization results such as transmission electron microscopy (TEM), X‐ray diffraction (XRD), The Ultraviolet–visible spectroscopy diffuse reflectance spectroscopy (UV‐vis DRS), Photoluminescence (PL) and nitrogen adsorption‐desorption isotherms (BET) etc. indicate that the Ni2P nanoparticles loaded on the CdS/g‐C3N4 exposed more active sites and facilitated the efficiency of photogenic electron‐hole pairs separation. Optimistically, these results were good consistent with each other. This considerable performance probablely attribute to the special conduction band (CB) and valence band (VB) of CdS and g‐C3N4 which form a heterojuction and the introduction of Ni2P as cocatalyst further extract photogenerated electrons that lower the over potential of H+ redution.
Study the Mechanism of Enhanced Li Storage Capacity through Decreasing Internal Resistance by High Electronical Conductivity via Sol‐gel Electrospinning of Co3O4 Carbon Nanofibers
Authors: Liu Jifei , Fu Bi , Dai Jianfeng , Zhu Xiaojun , Wang Qing
Published: March 2019

Co3O4@nanofibers (NFs) and Co3O4@carbon NFs (CNFs) were synthesized by sol‐gel electrospinning followed by annealing in air and Ar atmosphere, respectively. Co3O4@NFs and Co3O4@CNFs deliver stable cyclic performance with Li storage capacity of 330 and 400mAh/g after 170 and 200 cycles, respectively. Co3O4@CNFs deliver higher Li storage capacity more than Co3O4@NFs at each current densities in rate performance. More importantly, Co3O4@CNFs demonstrated relatively smaller internal resistance result from the comparison of electrochemical independence spectrum. Further morphology observation of the cycled electrodes indicates that the one‐dimensioncal nanostrucutre of the Co3O4@CNFs is still maintaned after reacting with Li+, which is singnicicant to the electrochemical cyclic performance. This study indicates the internal resistance can be decreased by increasing electronical conductivity through electrospinning carbon coating layer, resulting in an enhanced energy storage performance.
Graphene‐Coated Spandex Sensors Embedded into Silicone Sheath for Composites Health Monitoring and Wearable Applications
Authors: Montazerian Hossein , Rashidi Armin , Dalili Arash , Najjaran Homayoun , Milani Abbas S. , Hoorfar Mina
Published: March 2019

This study presents a low‐cost, tunable, and stretchable sensor fabricated based on spandex (SpX) yarns coated with graphene nanoplatelets (GnP) through a dip‐coating process. The SpX/GnP is wrapped into a stretchable silicone rubber (SR) sheath to protect the conductive layer against harsh conditions, which allows for fabricating washable wearable sensors. Dip‐coating parameters are optimized to obtain the maximum GnP coating rate. The covering sheath is tailored to achieve high stretchability beyond the sensing limit of 104% for SpX/GnP/SR sensors. Adjustable sensitivity is attained by manipulating SpX immersion times broadening its application for a wide range of strains: Gauge factors as high as two orders of magnitude are achieved at tensile strains greater than ≈40%. The fabricated sensors are tested for two applications: First, the SpX/GnP sensors are integrated into composite fabrics (with no negative impact on the structural integrity of the part) for screening the yarn displacements, resin flow, solidification during the hot press forming process, and structural health monitoring under mechanical loads with minimal cross‐sensitivity to temperature/humidity. Second, the capability of SpX/GnP/SP sensors in detection of a wide range of bodily motions (from the joint motion to arterial blood pressure) is demonstrated.
Enhanced Enzyme Activity through Scaffolding on Customizable Self‐Assembling Protein Filaments
Authors: Lim Samuel , Jung Gi Ahn , Glover Dominic J. , Clark Douglas S.
Published: March 2019

Precisely organized enzyme complexes are often found in nature to support complex metabolic reactions in a highly efficient and specific manner. Scaffolding enzymes on artificial materials has thus gained attention as a promising biomimetic strategy to design biocatalytic systems with enhanced productivity. Herein, a versatile scaffolding platform that can immobilize enzymes on customizable nanofibers is reported. An ultrastable self‐assembling filamentous protein, the gamma‐prefoldin (γ‐PFD), is genetically engineered to display an array of peptide tags, which can specifically and stably bind enzymes containing the counterpart domain through simple in vitro mixing. Successful immobilization of proteins along the filamentous template in tunable density is first verified using fluorescent proteins. Then, two different model enzymes, glucose oxidase and horseradish peroxidase, are used to demonstrate that scaffold attachment could enhance the intrinsic catalytic activity of the immobilized enzymes. Considering the previously reported ability of γ‐PFD to bind and stabilize a broad range of proteins, the filament's interaction with the bound enzymes may have created a favorable microenvironment for catalysis. It is envisioned that the strategy described here may provide a generally applicable methodology for the scaffolded assembly of multienzymatic complexes for use in biocatalysis.
High‐Indexed PtNi Alloy Skin Spiraled on Pd Nanowires for Highly Efficient Oxygen Reduction Reaction Catalysis
Authors: Zhao Yueping , Tao Lu , Dang Wei , Wang Linlin , Xia Meirong , Wang Bo , Liu Minmin , Gao Faming , Zhang Jiujun , Zhao Yufeng
Published: March 2019

The catalytic performance of Pt‐based catalysts for oxygen reduction reactions (ORR) can generally be enhanced by constructing high‐index exposed facets (HIFs). However, the synthesis of Pt alloyed high‐index skins on 1D non‐Pt surfaces to further improve Pt utilization and stability remains a fundamental challenge for practical nanocrystals. In this work, Pd nanowires (NWs) are selected as a rational medium to facilitate the epitaxial growth of Pt and Ni. Based on the different nucleation and growth habits of Pt and Ni, a continuous PtNi alloy skin bounded with HIFs spiraled on a Pd core can be obtained. Here, the as‐prepared helical Pd@PtNi NWs possess high HIF densities, low Pt contents, and optimized oxygen adsorption energies, demonstrating an enhanced ORR mass activity of 1.75 A mgPt−1 and a specific activity of 3.18 mA cm−2, which are 10 times and 12 times higher than commercial Pt/C catalysts, respectively. In addition, the 1D nanostructure enables the catalyst to be highly stable after 30 000 potential sweeping cycles. This work successfully extends bulky high‐indexed Pt alloys to core–shell nanostructures with the design of a new, highly efficient and stable Pt‐based catalyst for fuel cells.
On the Correlation between Suitable Material Parameters for the Prediction of Local Formability of Advanced High Strength Steels
Authors: Denks Ingwer A. , Schneider Matthias , Westhäuser Sebastian , Lesch Christian
Published: March 2019

The reliable prediction of local formability, for example, the performance in hole expansion test (HET), requires suitable material parameters. One proposed parameter for AHSS is true fracture strain (TFS), that is, “local ductility”. In this study TFS is measured by tensile tests and by hole expanding tests with Nakajima setup. The main outcome is that a general correlation of local ductility and hole expansion ratio from HET, as claimed for cold rolled steel grades in recent publications, cannot be confirmed, particularly when considering hot rolled steel grades. Thus, an additional parameter is introduced named “crack resistivity” which is defined as the maximum local true fracture strain at the edges of samples pierced by shear cutting and tested in the Nakajima setup. It is shown that crack resistivity correlates with the hole expansion ratio whereas a correlation with local ductility does not exist. Hence, when regarding steels of different process routes (i.e., hot and cold rolled steels grades), the prediction of local formability (in a general sense) requires measures of local ductility and crack resistivity. Consequently, for any general classification scheme, local ductility and crack resistivity must be considered besides global ductility (i.e., uniform elongation).
Response Surface Optimization of Reduced Fat o/w Emulsions Formulated with Cornstarch Nanocrystal as a Novel Fat Replacer
Authors: Javidi Fatemeh , Razavi Seyed M. A. , Mohammad Amini Asad
Published: March 2019

In this study, a face central composite design (FCCD) is applied to optimize the formulation of reduced fat o/w emulsions containing cornstarch nanocrystal (CSNC) as a novel fat replacer. Data analysis shows that independent variables including fat replacement levels (25, 50, and 75%) and CSNC concentration (10, 12, and 14%) significantly (p < 0.05) affect all responses. In this regard, increases in the levels of both fat replacement and CSNC decrease the droplet size and increase the values of yield stress, elastic modulus at 1 Hz, slope of tan delta at non‐linear viscoelastic region and degree of thixotropy, indicating a stronger gel network formed. Numerical optimization is used to determine the optimum formulation of the reduced‐fat emulsion based on properties of a full‐fat emulsion. This optimum point is estimated to be 47.80% of fat replacement and 11.99% of CSNC concentration. Closeness between the experimental and predicted values of the studied characteristics demonstrates the suitability of the corresponding models. Furthermore, the storage of full‐fat and optimum reduced‐fat emulsions at 4 °C for one month leads to an increase in droplet size from 144 to 496 nm and from 149 to 234 nm, respectively. However, no creaming is observed for each sample throughout the storage time.
An agentive focus may limit learning about complex causality and systems dynamics: A study of seventh graders' explanations of ecosystems
Authors: Cuzzolino Megan Powell , Grotzer Tina A. , Tutwiler M. Shane , Torres Eric W.
Published: March 2019

Agent‐oriented pedagogies have been used in teaching concepts related to complex systems dynamics. However, little research has systematically explored the role of a strong agency‐oriented focus on understanding of complex, dynamic ecological systems. This study analyzed seventh graders' (n = 216) explanations of a complex ecological scenario. The findings show that students were more likely to generate agentive than nonagentive explanations and students who adopted an agentive framing were least likely to understand the complex causal dynamics of two environmental scenarios, eutrophication in a pond and acid rain in a forest. Furthermore, students' initial inclination toward agency‐oriented explanation on the assessment was predictive of their performance on a postassessment following an instructional opportunity to learn about ecosystems dynamics; a strong agency orientation corresponded to less complex interpretations of the dynamics of the ecosystems. The results suggest that a strongly agentive perspective may limit students' ability to learn complex systems dynamics and that the pedagogical advantages of agent‐based approaches may not be without limitations.
Epimagnolin A inhibits IL‐6 production by inhibiting p38/NF‐κB and AP‐1 signaling pathways in PMA‐stimulated THP‐1 cells
Authors: Chun Hyun‐Woo , Kim Soo‐Jin , Pham Thu‐Huyen , Bak Yesol , Oh Jaewook , Ryu Hyung‐Won , Oh Sei‐Ryang , Hong Jin‐Tae , Yoon Do‐Young
Published: March 2019

Epimagnolin A is a lignan obtained from the flower buds of Magnolia fargesii, which is traditionally used in Asian medicine for treating headache and nasal congestion. A herbal compound fargesin obtained from M. fargesii, has exerted anti‐inflammatory effects in human monocytic THP‐1 cells in the previous study. The anti‐inflammatory effects of epimagnolin A, however, have been not elucidated yet. In this study, it was demonstrated that epimagnolin A reduced phorbol‐12‐myristate‐13‐acetate (PMA)‐induced IL‐6 promoter activity and IL‐6 production in human monocytic THP‐1 cells. Furthermore, it was investigated the modulating effects of epimagnolin A on mitogen‐activated protein kinase, nuclear factor‐kappa B (NF‐κB), and activator protein 1 (AP‐1) activities. Phosphorylation of p38 and nuclear translocation of p50 and c‐Jun were down‐regulated by epimagnolin A in the PMA‐stimulated THP‐1 cell. The results revealed that epimagnolin A attenuated the binding affinity of NF‐κB and AP‐1 transcription factors to IL‐6 promoter and IL‐6 production through p38/NF‐kB and AP‐1 signaling pathways in the PMA‐stimulated THP‐1 cells. These results suggest that epimagnolin A can be a useful drug for the treatment of inflammatory diseases.
Development of the hematopoietic system: Role of inflammatory factors
Authors: Hayashi Yoshikazu , Sezaki Maiko , Takizawa Hitoshi
Published: March 2019

Hematopoietic stem cells (HSCs) have two defining features, multipotency and self‐renewal, both of which are tightly controlled by cell autonomous programs and environmental factors throughout the lifetime of an organism. During development, HSCs are born in the aorta‐gonad‐mesonephros region, and migrate to distinct hematopoietic organs such as the placenta, fetal liver and spleen, continuously self‐renewing and expanding to reach a homeostatic number. HSCs ultimately seed the bone marrow around the time of birth and become dormant to sustain lifelong hematopoiesis. In this review, we will summarize the recent findings on the role of inflammatory factors regulating HSC development, that is, emergence, trafficking and differentiation. An understanding of HSC kinetics during developmental processes will provide useful knowledge on HSC behavior under physiological and pathophysiological conditions.

This article is categorized under:

Adult Stem Cells, Tissue Renewal, and Regeneration > Regeneration

Adult Stem Cells, Tissue Renewal, and Regeneration > Tissue Stem Cells and Niches

Adult Stem Cells, Tissue Renewal, and Regeneration > Environmental Control of Stem Cells
Variations on S-fold CFTs
Authors: Garozzo Ivan , Monaco Gabriele Lo , Mekareeya Noppadol
Published: March 2019

Abstract

A local SL(2, ℤ) transformation on the Type IIB brane configuration gives rise to an interesting class of superconformal field theories, known as the S-fold CFTs. Previously it has been proposed that the corresponding quiver theory has a link involving the T(U(N)) theory. In this paper, we generalise the preceding result by studying quivers that contain a T(G) link, where G is self-dual under S-duality. In particular, the cases of G = SO(2N), USp′(2N) and G
2 are examined in detail. We propose the theories that arise from an appropriate insertion of an S-fold into a brane system, in the presence of an orientifold threeplane or an orientifold fiveplane. By analysing the moduli spaces, we test such a proposal against its S-dual configuration using mirror symmetry. The case of G
2 corresponds to a novel class of quivers, whose brane construction is not available. We present several mirror pairs, containing G
2 gauge groups, that have not been discussed before in the literature.
Gauged fermionic matrix quantum mechanics
Authors: Berenstein David , de Mello Koch Robert
Published: March 2019

Abstract

We consider the gauged free fermionic matrix model, for a single fermionic matrix. In the large N limit this system describes a c = 1/2 chiral fermion in 1 + 1 dimensions. The Gauss’ law constraint implies that to obtain a physical state, indices of the fermionic matrices must be fully contracted, to form a singlet. There are two ways in which this can be achieved: one can consider a trace basis formed from products of traces of fermionic matrices or one can consider a Schur function basis, labeled by Young diagrams. The Schur polynomials for the fermions involve a twisted character, as a consequence of Fermi statistics. The main result of this paper is a proof that the trace and Schur bases coincide up to a simple normalization coefficient that we have computed.
Generalized hot attractors
Authors: Goldstein Kevin , Jejjala Vishnu , Mashiyane James Junior , Nampuri Suresh
Published: March 2019

Abstract

Non-extremal black holes are endowed with geometric invariants related to their horizon areas. We extend earlier work on hot attractor black holes to higher dimensions and add a scalar potential. In addition to the event and Cauchy horizons, when we complexify the radial coordinate, non-extremal black holes will generically have other horizons as well. We prove that the product of all of the horizon areas is independent of variations of the asymptotic moduli further generalizing the attractor mechanism for extremal black holes. In the presence of a scalar potential, as typically appears in gauged supergravity, we find that the product of horizon areas is not necessarily the geometric mean of the extremal area, however. We outline the derivation of horizon invariants for stationary backgrounds.
Downstream consequences of pubertal timing for young women's body beliefs
Authors: Grower Petal , Ward L. Monique , Beltz Adriene M.
Published: March 2019

Introduction

Puberty is a critical biopsychosocial event that has long‐term consequences for adolescents' behavior and well‐being. Research has shown that developing earlier than one's peers may worsen adolescent girls' body image, in part due to weight redistribution and increases in adiposity resulting from pubertal development. However, research has yet to examine if pubertal timing is associated with girls' body beliefs related to self‐objectification, self‐sexualization, and positive body image beyond the adolescent years. We address that issue here.

Methods

Participants were 287 undergraduate White women (Mage = 18.62, SDage = 0.93) from the United States who completed surveys containing a retrospective report of pubertal timing and several scales assessing their current body beliefs.

Results

Regression analyses demonstrated that earlier pubertal timing was linked to greater body surveillance, greater sex appeal self‐worth, and less body appreciation, but not to body shame or enjoyment of sexualization, which were negatively related to age.

Conclusions

This study provides preliminary evidence that pubertal timing has downstream consequences for a variety of women's body beliefs. However, older women reported less body shame and less enjoyment of sexualization than younger women, suggesting possible age (and not puberty‐) related developmental trends in these two body beliefs. These findings highlight a need for future work with larger, more diverse samples and longitudinal data.