bluuebunny/crossref_metadata_2025_split huggingface dataset:
Signals of forest degradation in the demography of common Asian amphibians
Authors: Karraker Nancy E. , Fischer Samantha , Aowphol Anchalee , Sheridan Jennifer , Poo Sinlan 
Published: January 2018

BackgroundLowland areas in tropical East and Southeast Asia have a long history of conversion from forestland to agricultural land, with many remaining forests being chronically degraded by wood cutting, livestock grazing, and burning. Wetland-breeding amphibians that have evolved in lowland forests in the region have adjusted to changes in habitat composition caused by humans’ activities, and populations continue to persist. However, we have little understanding of the impacts of forest disturbance on these species beyond assessments of abundance and distribution, and species considered to be common and widespread have been largely neglected.MethodsWe examined body condition and sex ratios of toads (Duttaphrynus melanostictus), predation risk in treefrogs (2Polypedatesspp.), and growth and survival of leaf litter frogs (2Microhylaspp.) in agricultural land, degraded forest, and intact forest in two study areas, Thailand and Hong Kong.ResultsToad populations exhibited higher body condition and female-biased sex ratios in intact forest. Predation of treefrog embryos by flies was lower in intact and degraded forests than in agricultural land. Embryonic survival and larval growth and survival in leaf litter frogs were lower in intact forests than in agricultural land. Results for each study were similar between study areas.DiscussionFor three of five of these common amphibian species, we documented signals of forest loss and disturbance in their populations. Although these species occur in disturbed habitats, loss of forest cover continues to degrade aspects of their population demography. We urge conservation biologists to consider that populations of species appearing to be common, widespread, and tolerant of human disturbance may be eroding over time.
Change in Dense Shelf Water and Adélie Land Bottom Water Precipitated by Iceberg Calving
Authors: Snow K. , Rintoul S. R. , Sloyan B. M. , Hogg A. McC. 
Published: January 2018

AbstractAntarctic Bottom Water supplies the deep limb of the global overturning circulation and ventilates the abyssal ocean. Antarctic Bottom Water has warmed, freshened, and contracted in recent decades, but the causes remain poorly understood. We use unique multiyear observations from the continental shelf and deep ocean near the Mertz Polynya to examine the sensitivity of this bottom water formation region to changes on the continental shelf, including the calving of a large iceberg. Postcalving, the seasonal cycle of Dense Shelf Water (DSW) density almost halved in amplitude and the volume of DSW available for export reduced. In the deep ocean, the density and volume of Adélie Land Bottom Water decreased sharply after calving, while oxygen concentrations remained high, indicating continued ventilation by DSW. This natural experiment illustrates how local changes in forcing over the Antarctic continental shelf can drive large and rapid changes in the abyssal ocean.
Limited Impact of Subglacial Supercooling Freeze‐on for Greenland Ice Sheet Stratigraphy
Authors: Dow Christine F. , Karlsson Nanna B. , Werder Mauro A. 
Published: January 2018

AbstractLarge units of disrupted radiostratigraphy (UDR) are visible in many radio‐echo sounding data sets from the Greenland Ice Sheet. This study investigates whether supercooling freeze‐on rates at the bed can cause the observed UDR. We use a subglacial hydrology model to calculate both freezing and melting rates at the base of the ice sheet in a distributed sheet and within basal channels. We find that while supercooling freeze‐on is a phenomenon that occurs in many areas of the ice sheet, there is no discernible correlation with the occurrence of UDR. The supercooling freeze‐on rates are so low that it would require tens of thousands of years with minimal downstream ice motion to form the hundreds of meters of disrupted radiostratigraphy. Overall, the melt rates at the base of the ice sheet greatly overwhelm the freeze‐on rates, which has implications for mass balance calculations of Greenland ice.
Cassini CAPS Identification of Pickup Ion Compositions at Rhea
Authors: Desai R. T. , Taylor S. A. , Regoli L. H. , Coates A. J. , Nordheim T. A. , Cordiner M. A. , Teolis B. D. , Thomsen M. F. , Johnson R. E. , Jones G. H. , Cowee M. M. , Waite J. H. 
Published: January 2018

AbstractSaturn's largest icy moon, Rhea, hosts a tenuous surface‐sputtered exosphere composed primarily of molecular oxygen and carbon dioxide. In this Letter, we examine Cassini Plasma Spectrometer velocity space distributions near Rhea and confirm that Cassini detected nongyrotropic fluxes of outflowing
during both the R1 and R1.5 encounters. Accounting for this nongyrotropy, we show that these possess comparable along‐track densities of ∼2 × 10−3 cm−3. Negatively charged pickup ions, also detected during R1, are surprisingly shown as consistent with mass 26 ± 3 u which we suggest are carbon‐based compounds, such as CN−,
,
, or HCO−, sputtered from carbonaceous material on the moon's surface. The negative ions are calculated to possess along‐track densities of ∼5 × 10−4 cm−3 and are suggested to derive from exogenic compounds, a finding consistent with the existence of Rhea's dynamic CO2 exosphere and surprisingly low O2 sputtering yields. These pickup ions provide important context for understanding the exospheric and surface ice composition of Rhea and of other icy moons which exhibit similar characteristics.
Bifunctional Heterostructure Assembly of NiFe LDH Nanosheets on NiCoP Nanowires for Highly Efficient and Stable Overall Water Splitting
Authors: Zhang Haojie , Li Xiaopeng , Hähnel Angelika , Naumann Volker , Lin Chao , Azimi Sara , Schweizer Stefan L. , Maijenburg A. Wouter , Wehrspohn Ralf B. 
Published: January 2018

Abstract3D hierarchical heterostructure NiFe LDH@NiCoP/NF electrodes are prepared successfully on nickel foam with special interface engineering and synergistic effects. This research finds that the as‐prepared NiFe LDH@NiCoP/NF electrodes have a more sophisticated inner structure and intensive interface than a simple physical mixture. The NiFe LDH@NiCoP/NF electrodes require an overpotential as low as 120 and 220 mV to deliver 10 mA cm−2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1 m KOH, respectively. Tafel and electrochemical impedance spectroscopy further reveal a favorable kinetic during electrolysis. Specifically, the NiFe LDH@NiCoP/NF electrodes are simultaneously used as cathode and anode for overall water splitting, which requires a cell voltage of 1.57 V at 10 mA cm−2. Furthermore, the synergistic effect of the heterostructure improves the structural stability and promotes the generation of active phases during HER and OER, resulting in excellent stability over 100 h of continuous operation. Moreover, the strategy and interface engineering of the introduced heterostructure can also be used to prepare other bifunctional and cost‐efficient electrocatalysts for various applications.
Bioinspired, Spine‐Like, Flexible, Rechargeable Lithium‐Ion Batteries with High Energy Density
Authors: Qian Guoyu , Zhu Bin , Liao Xiangbiao , Zhai Haowei , Srinivasan Arvind , Fritz Nathan Joseph , Cheng Qian , Ning Mingqiang , Qie Boyu , Li Yi , Yuan Songliu , Zhu Jia , Chen Xi , Yang Yuan 
Published: January 2018

AbstractThe rapid development of flexible and wearable electronics proposes the persistent requirements of high‐performance flexible batteries. Much progress has been achieved recently, but how to obtain remarkable flexibility and high energy density simultaneously remains a great challenge. Here, a facile and scalable approach to fabricate spine‐like flexible lithium‐ion batteries is reported. A thick, rigid segment to store energy through winding the electrodes corresponds to the vertebra of animals, while a thin, unwound, and flexible part acts as marrow to interconnect all vertebra‐like stacks together, providing excellent flexibility for the whole battery. As the volume of the rigid electrode part is significantly larger than the flexible interconnection, the energy density of such a flexible battery can be over 85% of that in conventional packing. A nonoptimized flexible cell with an energy density of 242 Wh L−1 is demonstrated with packaging considered, which is 86.1% of a standard prismatic cell using the same components. The cell also successfully survives a harsh dynamic mechanical load test due to this rational bioinspired design. Mechanical simulation results uncover the underlying mechanism: the maximum strain in the reported design (≈0.08%) is markedly smaller than traditional stacked cells (≈1.1%). This new approach offers great promise for applications in flexible devices.
Copper(II)‐Schiff Base Complex‐Functionalized Polyacrylonitrile Fiber as a Green Efficient Heterogeneous Catalyst for One‐Pot Multicomponent Syntheses of 1,2,3‐Triazoles and Propargylamines
Authors: Li Pengyu , Liu Yuanyuan , Wang Lu , Xiao Jian , Tao Minli 
Published: January 2018

AbstractA series of copper(II)‐Schiff bases‐functionalized polyacrylonitrile fiber catalysts were successfully prepared using copper acetate as copper source and characterized by elemental analysis, fourier‐transfer infrared spectroscopy, ultraviolet‐visible spectroscopy, X‐ray photoelectron spectroscopy and inductively coupled plasma analysis. Excellent physical strength and thermal stability of the fiber catalysts were demonstrated by scanning electron microscopy, X‐ray diffraction, thermogravimetric/differential scanning calorimetry analysis and mechanical strength measurements. Furthermore, these catalysts were successfully applied to one‐pot multicomponent copper‐catalyzed azide‐alkyne cycloaddition (CuAAC) reaction and aldehyde, alkyne, amine (A3) coupling reaction in which the influences of different substituent groups on the catalytic activities of fiber catalysts were investigated in detail. Among them, the bis[N‐ethyl‐3,5‐di‐tert‐butyl‐salicylideneiminato]copper(II)‐functionalized polyacrylonitrile fiber (PANS2F−Cu) as a green, efficient catalyst exhibited the best catalytic activity for its high hydrophobic micro‐environment can aggregate the reactants to the catalytic sites and accelerate the reaction. In addition, the PANS2F−Cu has performed well in scaled‐up experiment and shown excellent recyclability (at least ten times), and these enable it to have great potential for further applications.magnified image
Barrier Reduction of Lithium Ion Tunneling through Graphene with Hybrid Defects: First‐Principles Calculations
Authors: Xin Yanbo , Huang Anping , Hu Qi , Shi Hongliang , Wang Mei , Xiao Zhisong , Zheng Xiaohu , Di Zengfeng , Chu Paul K. 
Published: January 2018

AbstractAtomically thin 2D materials such as graphene and hexagonal boron nitride are increasingly explored as a possible platform for atomic diffusion barriers and novel separation technologies. However, a perfectly dense networked lattice structure is impermeable to nearly all ions thereby limiting their application as atomically thin barriers. In this work, climbing image nudged elastic band simulation is applied to identify meaningful strategies to reduce the energy barrier height of Li ions tunneling through monolayer (ML) graphene sheets. Our results reveal that defects such as pore defects, ripples, and some atomic substitutions can effectively reduce the Li ion tunneling barrier and the defects can alter the Li ion adsorption energy to influence the deintercalation process. Furthermore, hybrid defects can balance the energy barrier and potential well to increase the permeability of Li ions through graphene sheets.
Interdependence of Resistance and Optical Transmission in Conductive Nanowire Networks
Authors: Ainsworth Catherine A. , Derby Brian , Sampson William W. 
Published: January 2018

AbstractMetallic nanowire networks show great potential for use in transparent conductive displays. The coupled relationship between the principal materials properties of interest for such applications, optical transmittance and sheet resistance, is known to be affected by both nanowire dimensions and area coverage. Existing theory to describe the observed interdependence requires consideration of both bulk and surface phases. Here, an analysis of structural variables in these materials is presented confirming that bulk considerations do not typically apply. Accordingly, a model using statistical theory for random line networks is developed that requires consideration of a surface phase only. The resultant simple expression relates sheet resistance and optical transmission of heterogeneous nanowire assemblies in terms of nanowire dimensions. Comparison of our model with experimental and simulation data from the literature shows excellent agreement. In closing, theoretical insights into the observed influence on sheet resistance of polydisperse nanowire lengths and structural variability are provided.
3D Flexible Carbon Felt Host for Highly Stable Sodium Metal Anodes
Authors: Chi Shang‐Sen , Qi Xing‐Guo , Hu Yong‐Sheng , Fan Li‐Zhen 
Published: January 2018

AbstractSodium (Na) metal, which possesses a high theoretical capacity and the lowest electrochemical potential, is regarded as a promising anode material for Na–metal batteries. However, both Na dendrite growth and large volume change in cycling have severely impeded its practical applications. This study demonstrates that a 3D flexible carbon (C) felt which is already commercialized in large‐scale can be employed as a host for prestoring Na via a melt infusion strategy, through which a Na/C composite anode is obtained. The resulting anode exhibits a stable voltage profile and a small hysteresis over 120 cycles in carbonate‐based electrolytes in symmetrical cells owing to the fact that the metallic Na is confined in a conductive carbon felt host, which increases the Na+ deposition sites to lower the effective current density and render a uniform Na nucleation, restricting the dimension change in electrochemical cycling. More importantly, effective inhibition of Na dendrite growth and large volume change is achieved. When coupled with a Na0.67Ni0.33Mn0.67O2 cathode, the Na/C composite demonstrates a good suitability in full cells. This work provides an alternative option for the fabrication of stable Na metal anodes, which is of great significance for the practical applications of Na metal anodes in high‐energy‐density batteries.
Flexible and Salt Resistant Janus Absorbers by Electrospinning for Stable and Efficient Solar Desalination
Authors: Xu Weichao , Hu Xiaozhen , Zhuang Shendong , Wang Yuxi , Li Xiuqiang , Zhou Lin , Zhu Shining , Zhu Jia 
Published: January 2018

AbstractWith recent progress in interfacial solar steam generation, direct solar desalination is considered a promising technology for providing a clean water solution through a cost effective and environmental‐friendly pathway. As a high and stable water production rate is the key to enable widespread applications, salt deposition becomes a critical issue that needs to be addressed. Herein, the authors demonstrate that a flexible Janus absorber fabricated by sequential electrospinning can enable stable and efficient solar desalination. Taking advantage of the unique structure of Janus, two functions of steam generation, solar absorption and water pumping, are decoupled into different layers, with an upper hydrophobic carbon black nanoparticles (CB) coating polymethylmethacrylate (PMMA) layer for light absorption, and a lower hydrophilic polyacrylonitrile (PAN) layer for pumping water. Therefore, salt can only be deposited in the hydrophilic PAN layer and quickly be dissolved because of continuous water pumping. Janus absorber demonstrates high efficiency (72%) and stable water output (1.3 kg m–2 h–1, over 16 days) under 1‐sun, not achieved in most previous absorbers. With a unique structure design achieved by scalable process, this flexible Janus absorber provides an efficient, stable and portable solar steam generator for direct solar desalination.
Changes of liver metabolites following hepatectomy with ischemia reperfusion towards liver regeneration
Authors: Saito Yu , Morine Yuji , Iwahashi Shuichi , Ikemoto Tetsuya , Imura Satoru , Yamanaka‐Okumura Hisami , Hirayama Akiyoshi , Soga Tomoyoshi , Tomita Masaru , Shimada Mitsuo 
Published: January 2018

AbstractBackgroundMetabolome analysis is one of the omics which investigates the final product of a central dogma. Changes of liver metabolites during liver regeneration following hepatectomy (Hx) continue to remain unclear. The aim of the present study was to investigate the changes of liver metabolites following Hx with ischemia reperfusion (I/R) towards liver regeneration.MethodsTwenty‐three patients who underwent Hx were enrolled in this study. Non‐tumor tissues were sampled immediately before and after Hx and a comparison was made between the liver samples taken before and after Hx using capillary electrophoresis (CE)—time‐of‐flight mass spectrometry (TOFMS) as metabolome analysis.ResultsThe metabolic pathway showed that there was a significant increase in “lactate” following Hx. There was a significant decrease in metabolites only in the first half of the tricarboxylic acid cycle (TCA) cycle, and adenosine triphosphate (ATP) by anaerobiotic glycolysis did not occur in time for energy consumption of the Hx. Principal component analysis revealed remarkably different component profiles between the samples taken before and after Hx. One hundred and three metabolites were selected as critical metabolites for separating components. Valine and tryptophan increased significantly after Hx and they were regulated by resected liver volume, ischemic time and liver function.ConclusionThe liver metabolites changed remarkably between before and after Hx. Especially, liver valine and tryptophan were increased.
Kinetic Resolution ofsec‐Thiols by Enantioselective Oxidation with Rationally Engineered 5‐(Hydroxymethyl)furfural Oxidase
Authors: Pickl Mathias , Swoboda Alexander , Romero Elvira , Winkler Christoph K. , Binda Claudia , Mattevi Andrea , Faber Kurt , Fraaije Marco W. 
Published: January 2018

AbstractVarious flavoprotein oxidases were recently shown to oxidize primary thiols. Herein, this reactivity is extended tosec‐thiols by using structure‐guided engineering of 5‐(hydroxymethyl)furfural oxidase (HMFO). The variants obtained were employed for the oxidative kinetic resolution of racemicsec‐thiols, thus yielding the corresponding thioketones and nonreactedR‐configured thiols with excellent enantioselectivities (E≥200). The engineering strategy applied went beyond the classic approach of replacing bulky amino acid residues with smaller ones, as the active site was additionally enlarged by a newly introduced Thr residue. This residue established a hydrogen‐bonding interaction with the substrates, as verified in the crystal structure of the variant. These strategies unlocked HMFO variants for the enantioselective oxidation of a range ofsec‐thiols.
Preparation of a branched amine and physical and thermal studies of epoxy compositions including the amine compound
Authors: Kim Taehee , Kim Sungyeon , Lee Dong‐gu , Lim Choong‐Sun , Seo Bongkuk 
Published: January 2018

ABSTRACTA branched amine, abbreviated as EATP, was synthesized by reacting ethylene diamine with methyl acrylate, followed by reaction with xylylene diamine via a two‐step process. The prepared EATP (in the range of 5–30 parts per resin) was added to epoxy compositions with bisphenol A epoxy resin and a curing agent, xylylene diamine. The epoxy compositions were cured at high temperatures and processed for flexural strength testing and dynamic mechanical analysis. The results showed that the flexural strength was improved by 13% when 10% EATP was present in the epoxy matrix, but there was a decrease in tan δ and storage modulus values. Moreover, the degree of fire hazard of the epoxy compositions and EATP was studied by measuring the heat release rate (HRR). The reduction in the HRR with higher amounts of EATP in the epoxy indicated that the xylylene groups of EATP enhance the thermal stability of the resin. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46233.
Synergistic effect of graphene oxide‐silver nanofillers on engineering performances of polyelectrolyte complex nanofiber membranes
Authors: Cai Ning , Zeng Huan , Fu Jing , Chan Vincent , Chen Mei , Li Hui , Yu Faquan 
Published: January 2018

ABSTRACTThe poor mechanical and antibacterial performance has become a big hurdle for extending the application of polyelectrolyte complex (PEC) nanofibers in various fields. In this study, chitosan/gelatin (CG) composite nanofiber system was used for portraying the synergistic enhancement of mechanical and antibacterial properties of PEC nanofiber membranes by inclusion of graphene oxide‐silver (GO‐Ag) nanofillers. In particular, the introduction of 1.5 wt % GO‐Ag has raised the elastic modulus and tensile strength of CG nanofiber membrane by 105% and 488%, respectively, which are partially attributed to the alleviated restacking of graphene sheets by the anchored AgNPs. Meanwhile, the diameters of inhibition zone againstEscherichia coliandStaphylococcus aureuson LB‐agar plates induced by GO‐Ag/CG nanofiber membranes are increased by 80.5% and 50.1%, respectively, compared to that by CG membrane. The synergistic improvement of antimicrobial performance of GO‐Ag/CG may be related to the accumulation of microorganisms induced by GO. In summary, the incorporation of GO‐Ag composite nanofillers has emerged as an effective strategy for engineering PEC nanofiber membranes for potential applications in nanomedicine and tissue engineering. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2018,135, 46238.
Improving the recombinant human erythropoietin glycosylation using microsome supplementation in CHO cell‐free system
Authors: Gurramkonda Chandrasekhar , Rao Aniruddha , Borhani Shayan , Pilli Manohar , Deldari Sevda , Ge Xudong , Pezeshk Niloufar , Han Tzu‐Chiang , Tolosa Michael , Kostov Yordan , Tolosa Leah , Wood David W. , Vattem Krishna , Frey Douglas D. , Rao Govind 
Published: January 2018

AbstractCell‐Free Protein Synthesis (CFPS) offers many advantages for the production of recombinant therapeutic proteins using the CHO cell‐free system. However, many complex proteins are still difficult to express using this method. To investigate the current bottlenecks in cell‐free glycoprotein production, we chose erythropoietin (40% glycosylated), an essential endogenous hormone which stimulates the development of red blood cells. Here, we report the production of recombinant erythropoietin (EPO) using CHO cell‐free system. Using this method, EPO was expressed and purified with a twofold increase in yield when the cell‐free reaction was supplemented with CHO microsomes. The protein was purified to near homogeneity using an ion‐metal affinity column. We were able to analyze the expressed and purified products (glycosylated cell‐free EPO runs at 25–28 kDa, and unglycosylated protein runs at 20 kDa on an SDS–PAGE), identifying the presence of glycan moieties by PNGase shift assay. The purified protein was predicted to have ∼2,300 IU in vitro activity. Additionally, we tested the presence and absence of sugars on the cell‐free EPO using a lectin‐based assay system. The results obtained in this study indicate that microsomes augmented in vitro production of the glycoprotein is useful for the rapid production of single doses of a therapeutic glycoprotein drug and to rapidly screen glycoprotein constructs in the development of these types of drugs. CFPS is useful for implementing a lectin‐based method for rapid screening and detection of glycan moieties, which is a critical quality attribute in the industrial production of therapeutic glycoproteins.