bluuebunny/crossref_metadata_2025_split huggingface dataset:
A method for estimating the height of a mesospheric density level using meteor radar
Authors: Younger J. P. , Reid I. M. , Vincent R. A. , Murphy D. J. 
Published: July 2015

AbstractA new technique for determining the height of a constant density surface at altitudes of 78–85 km is presented. The first results are derived from a decade of observations by a meteor radar located at Davis Station in Antarctica and are compared with observations from the Microwave Limb Sounder instrument aboard the Aura satellite. The density of the neutral atmosphere in the mesosphere/lower thermosphere region around 70–110 km is an essential parameter for interpreting airglow‐derived atmospheric temperatures, planning atmospheric entry maneuvers of returning spacecraft, and understanding the response of climate to different stimuli. This region is not well characterized, however, due to inaccessibility combined with a lack of consistent strong atmospheric radar scattering mechanisms. Recent advances in the analysis of detection records from high‐performance meteor radars provide new opportunities to obtain atmospheric density estimates at high time resolutions in the MLT region using the durations and heights of faint radar echoes from meteor trails. Previous studies have indicated that the expected increase in underdense meteor radar echo decay times with decreasing altitude is reversed in the lower part of the meteor ablation region due to the neutralization of meteor plasma. The height at which the gradient of meteor echo decay times reverses is found to occur at a fixed atmospheric density. Thus, the gradient reversal height of meteor radar diffusion coefficient profiles can be used to infer the height of a constant density level, enabling the observation of mesospheric density variations using meteor radar.
In Situ Investigation of the Oxidation of Cobalt‐Base Superalloys in the Environmental Scanning Electron Microscope
Authors: Weiser Martin , Reichmann Angelika , Albu Mihaela , Virtanen Sannakaisa , Poelt Peter 
Published: July 2015

AbstractSince their discovery in 2006, cobalt‐base superalloys have aroused increasing interest as potential materials for various high‐temperature applications. One of the still unsolved problems is their resistance to oxidation. In the present study, the very first stages of the oxidation process of a Co–9Al–9W alloy were investigated. To this aim, the progress of the oxidation process was continuously observed at high magnification in an environmental scanning electron microscope (ESEM). Oxidation starts not necessarily at the grain boundaries, and both the onset temperature and the oxidation rate depend on the crystallographic orientation of the crystallites.
Effects of co‐plasticization of acetyl tributyl citrate and glycerol on the properties of starch/PVA films
Authors: Wang Wentao , Diao Enjie , Zhang Hui , Dai Yangyong , Hou Hanxue , Dong Haizhou 
Published: July 2015

ABSTRACTStarch/polyvinyl alcohol (PVA) nanocomposite films by film blowing process were successfully obtained. Starch (1700 g), PVA (300 g), and organically modified montmorillonite (OMMT, 200 g) were blended and plasticized with acetyl tributyl citrate (ATBC) and glycerol (GLY) at weight ratios of 0/100, 5/95, 10/90, 15/85, 20/80, and 25/75. The structural, morphology, barrier, mechanical, and thermal properties of the films, as well as molecular interactions in the nanocomposites were analyzed. The 3.98 nm d‐spacing was the highest in starch/PVA nanocomposite films plasticized with ATBC/GLY ratio of 10/90. The film with ATBC/GLY (5/95) had the lowest WVP (3.01 × 10−10 g m−1 s−1 Pa−1). The longitudinal tensile strength (TS) of starch/PVA nanocomposite films gradually increased from 4.46 to 6.81 MPa with the increase of ATBC/GLY ratios. The Tg steadily increased from 49.2°C to 55.2°C and the ΔH of the nanocomposite films decreased from 81.77 to 51.43 J/g at the presence of ATBC. The addition of ATBC into GLY plasticized starch/PVA/OMMT system enhanced the intermolecular interaction in the nanocomposites. This study proved that ATBC was an excellent compatibilizer in the preparation of starch/PVA/OMMT nanocomposite films. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42544.
Polysulfone‐based anion exchange polymers for catalyst binders in alkaline electrolyzers
Authors: Schauer Jan , Žitka Jan , Pientka Zbyněk , Křivčík Jan , Hnát Jaromír , Bouzek Karel 
Published: July 2015

ABSTRACTThe preparation of quaternized bisphenol A polysulfone (PSf) by chloromethylation and quaternization with trimethylamine (TMA), 1,4‐diazabicyclo[2.2.2]octane (DABCO), 1‐methylimidazole (MI), or 1,2‐dimethylimidazole (DMI) is described. While the ion‐exchange capacities (IECs) of MI or DMI quaternized PSf significantly decrease in concentrated KOH solutions at 60°C, the IECs of TMA or DABCO quaternized PSf are not much affected, but the membranes of these polymers become brittle. TMA quaternized PSf (IEC = 1.21 meq/g; IC = 2.45 S/m) and DABCO quaternized PSf (IEC = 1.09 meq/g; IC = 2.49 S/m) were used to bind a NiCo2O4 spinel electrocatalyst on the anode of Ni foam. Both the quaternized PSfs were quite effective in water electrolysis when used as binders, but not more effective than PTFE when rear sides of electrodes were fed with 10 wt % aqueous KOH solution. For long‐term electrolysis, binders based on more stable anion‐conductive polymers should be developed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42581.
Effect of hybrid filler (HNTs‐phthalocyanine) on the thermal properties and flammability of diene rubber
Authors: Rybiński Przemysław , Pająk Agnieszka , Janowska Grażyna , Jóźwiak Małgorzata 
Published: July 2015

ABSTRACTRubber is an essential polymer widely used in the auto‐industry. We report a method for the synthesis of zinc phtalocyanine (ZP), chloroalumino phthalocyanine (CP), and their hybrid fillers obtained by the synthesis of the two phtalocyanines in the presence of halloysite nanotubes (HNTs). The hybrid fillers were characterized by means of microscopic, thermal, and particle size measurement analysis. The effect of these fillers on the properties of diene rubbers were assessed in comparison with a physical mixture of halloysite and ZP or CP pigment. The dispersion degree of hybrid fillers inside an elastomeric matrix (rubber) was assessed with the atomic force microscopy. The influence of the hybrid fillers on the thermal and mechanical properties and flammability of butadiene‐acrylonitrile (NBR) and butadiene‐styrene (SBR) rubbers was assessed by analyzing the measurement results obtained by means of thermogravimetric analysis, differential scanning calorimetry, Zwick Tensile testing, FAA micro‐calorimeter, and oxygen index determination. We found that regardless of the spatial network structure of NBR and SBR rubbers, the incorporation of hybrid fillers into the matrix of the elastomers showed an improvement in their thermal and mechanical properties as well as a significant reduction in flammability. The improvement is attributed to the smaller size and much better dispersion of HZ and HC in relation to the particles of phthalocyanine. The colored composites of NBR rubber, containing hybrid filler (HZ or HC), showed an increase in the heat capacity compared to the uncolored samples, which can increase safety by facilitating the processes of self‐extinguishing. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42593.
Reinforcement in the mechanical properties of shape memory liquid crystalline epoxy composites
Authors: Guo Huilong , Li Yinwen , Zheng Jian , Gan Jianqun , Liang Liyan , Wu Kun , Lu Mangeng 
Published: July 2015

ABSTRACTIn this work, novel thermoresponsive shape memory composites based on glass fiber and nanosilica‐modified liquid crystalline epoxies (LCEs) with lateral substituent were prepared and characterized. According to the comprehensive analysis of polarized optical microscopy, wide‐angle X‐ray diffraction measurements, and tan δ data, the orientation of mesogen units were hindered by the introduction of nanosilica and lateral substituents of liquid crystalline epoxies, so that additional physical cross‐links except for similar chemical cross‐links emerged with the introduction of surface‐treated nanosilica. And the increased cross‐links could enhance the shape memory properties of the composites which could recover to their original state quickly in a time shorter than 30 s with high shape fixing ratios (>96%) and high shape recovery ratios (>98%), which indicated the composites could be applied into self‐deployable structural materials. Moreover, the reinforcement in the dynamic storage moduli, tensile modulus, and the tensile strength and shape memory properties indicated that glass fiber and nanosilica‐modified shape memory liquid crystalline epoxy composites could be high‐performance composites and could be used as new candidates for aerospace smart materials. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42616.
Influence of temperature on the microstructure and mechanical properties of stretched polypropylene
Authors: Li Keran , Xiong Bijin , Cao Ya 
Published: July 2015

ABSTRACTMicrostructure and mechanical properties of isotactic polypropylene (iPP) stretched at different temperatures were studied. Strain‐induced fibrils were observed after stretching. Crystallinity (Xc), crystallite thickness (Lc), long period (Lpf), and diameter (Df) of fibrils were characterized by Differential Scanning Calorimetry and Small angle X‐ray scattering. Lpf of stretched iPP below 60°C was found to be lower than undrawn iPP. Xc, Lc, and Df increased with increasing draw temperature. Tensile test showed that Young's moduli of stretched iPPs were negatively dependent on Xc and Lc. The fraction of taut tie molecules was estimated from the mechanical model. Results showed that more tie molecules were formed in the samples stretched at lower temperatures. Dynamical mechanical analysis showed that glass transition temperature was strongly dependent on the draw temperature. The glass transition peak disappeared in stretched iPPs obtained below 80°C. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42622.
Fabrication of Mesoporous CoS2 Nanotube Arrays as the Counter Electrodes of Dye‐Sensitized Solar Cells
Authors: Tsai Jung‐Che , Hon Min‐Hsiung , Leu Ing‐Chi 
Published: July 2015

AbstractMesoporous cobalt sulfide nanotube arrays on FTO‐coated glass were synthesized by combining three simple technologies: the selective etching of ZnO sacrificial templates, mesoporous Co3O4 formation from cobalt‐chelated chitosan, and ion‐exchange reaction (IER). The mesoporous Co3O4 nanotubes composed of the Co3O4 nanoparticles possess a high surface area and are taken advantage for further removal of templates and IER. The morphologies and crystal structures of the CoS2 nanotube arrays were characterized by SEM, TEM, and XRD analyses. Their electrocatalytic properties were determined by electrochemical analyses including cyclic voltammetry measurements and Tafel polarization. The DSSCs assembled with a CoS2 counter electrode achieved a power conversion efficiency of 6.13 %, which was comparable to that of the DSSC with the Pt counter electrode (6.04 %). This indicates that the mesoporous CoS2 nanotube array can be a low‐cost and efficient alternative for the reduction of electrolytes in DSSCs.
AgBi(WO4)2: A New Modification Material to Bi2WO6 for Enhanced and Stable Visible‐Light Photocatalyic Performance
Authors: Feng Cuiyun , Dong Yuming , Jiang Pingping , Wang Guangli , Zhang Jingjing , Wu Xiuming , Zhang Chi 
Published: July 2015

AbstractIn this work, we report a novel AgBi(WO4)2–Bi2WO6 heterostructure, which was designed and synthesized by using a simple hydrothermal method. Methyl orange was used as a representative dye indicator to evaluate the visible‐light catalytic activity and the catalytic mechanism was investigated. The as‐synthesized AgBi(WO4)2–Bi2WO6 composite displayed a 43 times higher photocatalytic activity than Bi2WO6. Owing to the matched band gap and distinctive heterostructure, AgBi(WO4)2–Bi2WO6 reveals a high visible‐light response and high‐efficiency utilization of both photogenerated electrons and holes. AgBi(WO4)2 reveals a similar energy level to and good lattice match with Bi2WO6, which are favorable qualities for band bending and fluent electron transfer. Furthermore, the photoexcited electrons can produce oxygen to generate .O2− radicals, which is vital for the overall utilization of both holes and electrons. This is the first example of AgBi(WO4)2 being used as photocatalytic material.
Effect of methylene group insertions on the structural rigidity of Aib containing helices
Authors: Duley Anju , Gowda Vasantha , Ganjiwale Anjali , Raghothama Srinivasarao , Ramanathan Gurunath 
Published: July 2015

ABSTRACTNonprotein amino acids are being extensively used in the design of synthetic peptides to create new structure mimics. In this study we report the effect of methylene group insertions in a heptapeptide Boc‐Ala1‐Leu2‐Aib3‐Xxx4‐Ala5‐Leu6‐Aib7‐OMe which nicely folds into a mixed 310‐/α‐helical structure when Xxx= Ala. Analogs of this peptide have been made and studied by replacing central Xxx4 residue with Glycine (α‐residue), β‐Alanine (β‐Αla), γ‐aminobutyric acid (Gaba), and ε‐aminocaproic acid (ε‐Aca). NMR and circular dichroism were used to study the solution structure of these peptides. Crystals of the peptides containing alanine, β‐Αla, and Gaba reveal that increasing the number of central methylene (‐CH2‐) groups introduces local perturbations even as the helical structure is retained. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 104: 720–732, 2015.
Neighbor‐directed histidine N (τ)–alkylation: A route to imidazolium‐containing phosphopeptide macrocycles
Authors: Qian Wen‐Jian , Park Jung‐Eun , Grant Robert , Lai Christopher C. , Kelley James A. , Yaffe Michael B. , Lee Kyung S. , Burke Terrence R. 
Published: July 2015

ABSTRACTOur recently discovered, selective, on‐resin route to N(τ)‐alkylated imidazolium‐containing histidine residues affords new strategies for peptide mimetic design. In this, we demonstrate the use of this chemistry to prepare a series of macrocyclic phosphopeptides, in which imidazolium groups serve as ring‐forming junctions. Interestingly, these cationic moieties subsequently serve to charge‐mask the phosphoamino acid group that directed their formation. Neighbor‐directed histidine N(τ)‐alkylation opens the door to new families of phosphopeptidomimetics for use in a range of chemical biology contexts. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 104: 663–673, 2015.
Application of gas diffusion electrodes in bioelectrochemical syntheses and energy conversion
Authors: Horst Angelika E.W. , Mangold Klaus‐Michael , Holtmann Dirk 
Published: July 2015

ABSTRACTCombining the advantages of biological components (e.g., reaction specificity, self‐replication) and electrochemical techniques in bioelectrochemical systems offers the opportunity to develop novel efficient and sustainable processes for the production of a number of valuable products. The choice of electrode material has a great impact on the performance of bioelectrochemical systems. In addition to the redox process at the electrodes, interactions of biocatalysts with electrodes (e.g., enzyme denaturation or biofouling) need to be considered. In recent years, gas diffusion electrodes (GDEs) have proved to be very attractive electrodes for bioelectrochemical purposes. GDEs are porous electrodes, that posses a large three‐phase boundary surface. At this interface, a solid catalyst supports the electrochemical reaction between gaseous and liquid phase. This mini‐review discusses the application of GDEs in microbial and enzymatic fuel cells, for microbial electrolysis, in biosensors and for electroenzymatic synthesis reactions. Biotechnol. Bioeng. 2016;113: 260–267. © 2015 Wiley Periodicals, Inc.
Long‐term maintenance of a microfluidic 3D human liver sinusoid
Authors: Prodanov Ljupcho , Jindal Rohit , Bale Shyam Sundhar , Hegde Manjunath , McCarty William J. , Golberg Inna , Bhushan Abhinav , Yarmush Martin L. , Usta Osman Berk 
Published: July 2015

ABSTRACTThe development of long‐term human organotypic liver‐on‐a‐chip models for successful prediction of toxic response is one of the most important and urgent goals of the NIH/DARPA's initiative to replicate and replace chronic and acute drug testing in animals. For this purpose, we developed a microfluidic chip that consists of two microfluidic chambers separated by a porous membrane. The aim of this communication is to demonstrate the recapitulation of a liver sinusoid‐on‐a‐chip, using human cells only for a period of 28 days. Using a step‐by‐step method for building a 3D microtissue on‐a‐chip, we demonstrate that an organotypic in vitro model that reassembles the liver sinusoid microarchitecture can be maintained successfully for a period of 28 days. In addition, higher albumin synthesis (synthetic) and urea excretion (detoxification) were observed under flow compared to static cultures. This human liver‐on‐a‐chip should be further evaluated in drug‐related studies. Biotechnol. Bioeng. 2016;113: 241–246. © 2015 Wiley Periodicals, Inc.
Real‐time imaging of anti‐biofilm effects using CP‐OCT
Authors: Rasmussen Karin , Reilly Cavan , Li Yuping , Jones Robert S. 
Published: July 2015

ABSTRACTThe objective of this study was to develop a method to reliably and reproducibly assess the physical properties of in vitro multi‐species plaque derived biofilms. A custom flow cell (FC) was designed to model oral cavity shear stresses on biofilms grown on hydroxyapatite (HA) discs. A finite‐element program (ANSYS 13) modeled flow velocities and wall shear stresses on the interior 3D dimensions. For the experiment, 1% chlorhexidine (CHX), 5 M urea, and a 1× phosphate‐buffered saline (PBS) were flown through the FC simulating oral rinsing. Near infrared cross‐polarization optical coherence tomography (CP‐OCT) non‐destructively imaged the fluid immersed biofilms in real time (20 frames/s). During low flow, the swell of the biofilm caused from 5 M urea was quite pronounced increase in vertical dimension. Biofilms exposed to 1% CHX showed a slight collapse in the vertical dimension of the biofilm during low flow. During high flow/high sheer stress, the 5 M urea solution effectively removed the biofilm, while both 1% CHX and 1× PBS did not remove biofilms even under high velocity/shear stress conditions. Biotechnol. Bioeng. 2016;113: 198–205. © 2015 Wiley Periodicals, Inc.
Association between volume of severely injured patients and mortality in German trauma hospitals
Authors:   TraumaRegister DGU®, Zacher M T , Kanz K-G , Hanschen M , Häberle S , van Griensven M , Lefering R , Bühren V , Biberthaler P , Huber-Wagner S 
Published: July 2015

Abstract

Background
The issue of patient volume related to trauma outcomes is still under debate. This study aimed to investigate the relationship between number of severely injured patients treated and mortality in German trauma hospitals.

Methods
This was a retrospective analysis of the TraumaRegister DGU® (2009–2013). The inclusion criteria were patients in Germany with a severe trauma injury (defined as Injury Severity Score (ISS) of at least 16), and with data available for calculation of Revised Injury Severity Classification (RISC) II score. Patients transferred early were excluded. Outcome analysis (observed versus expected mortality obtained by RISC-II score) was performed by logistic regression.

Results
A total of 39 289 patients were included. Mean(s.d.) age was 49·9(21·8) years, 27 824 (71·3 per cent) were male, mean(s.d.) ISS was 27·2(11·6) and 10 826 (29·2 per cent) had a Glasgow Coma Scale score below 8. Of 587 hospitals, 98 were level I, 235 level II and 254 level III trauma centres. There was no significant difference between observed and expected mortality in volume subgroups with 40–59, 60–79 or 80–99 patients treated per year. In the subgroups with 1–19 and 20–39 patients per year, the observed mortality was significantly greater than the predicted mortality (P &lt; 0·050). High-volume hospitals had an absolute difference between observed and predicted mortality, suggesting a survival benefit of about 1 per cent compared with low-volume hospitals. Adjusted logistic regression analysis (including hospital level) identified patient volume as an independent positive predictor of survival (odds ratio 1·001 per patient per year; P = 0·038).

Conclusion
The hospital volume of severely injured patients was identified as an independent predictor of survival. A clear cut-off value for volume could not be established, but at least 40 patients per year per hospital appeared beneficial for survival.
Engaging novice researchers in the process and culture of science using a “Pass‐the‐Problem” case strategy
Authors: White Harold B. , Usher David C. 
Published: July 2015

AbstractUndergraduates having their first research experience frequently have little idea of what to expect. Institutions offering summer research experiences attempt to address this issue through programs that introduce students to the process and culture of science. However, didactic approaches frequently bore students who prefer more interactive sessions. We describe a “Pass‐the‐Problem” case study approach that engages groups of students in useful discussions about the research environment they are entering. The cases presented here include keeping a thorough laboratory notebook, balancing laboratory and personal time demands, anxiety about formal presentations, unexpected federal regulatory inspection, working in a lab with limited funds, being used as a technician rather than a researcher, frustration with failed experiments, effects of promotion and tenure on laboratory atmosphere, the importance of reading the research literature, and questioning a career in science. These cases alert students to different situations they might encounter and stimulate discussion about how to deal with them. © 2015 by The International Union of Biochemistry and Molecular Biology, 43(5):341–344, 2015.
Continuous Synthesis and Thermal Elimination of Sulfinyl‐Route Poly(p‐Phenylene Vinylene) in Consecutive Flow Reactions
Authors: Zaquen Neomy , Baeten Evelien , Vandenbergh Joke , Lutsen Laurence , Vanderzande Dirk , Junkers Tanja 
Published: July 2015

AbstractContinuous synthesis of multistep polymerizations at microscale is made available by coupling two microstructured chip reactors in a single reactor setup. Conjugated [2‐methoxy‐5‐(3′,7′‐dimethyloctyloxy)]‐1,4‐phenylenevinylene (MDMO‐PPV) is synthesized via the radical sulfinyl precursor route. Reactions are carried out in separate reactors and optimization of the elimination of polymer can be effectively performed in a defined temperature range, allowing for full polymer conversion within minutes and formation of conjugated materials. The combination of both processes in a single coupled reactor setup permits total monomer‐to‐conjugated‐MDMO‐PPV conversions while retaining its pristine optical properties. Polymer characteristics are comparatively good and the reduction in yield due to the lower initial monomer concentrations is compensated by the much shorter reaction times required in the flow process.
Controlled Construction of Hierarchical Nanocomposites Consisting of MnO2 and PEDOT for High‐Performance Supercapacitor Applications
Authors: Tang Pengyi , Han Lijuan , Zhang Lin , Wang Shijie , Feng Wei , Xu Guoqing , Zhang Li 
Published: July 2015

AbstractThe front cover artwork is provided by the group of Professor Li Zhang from The Chinese University of Hong Kong and his collaborators from the Shenzhen Institutes of Advanced Technology, Chinese Academy of Science. The image shows the fabrication of core–shell–branch hierarchical MnO2@PEDOT@MnO2 nanocomposites, using simple electrochemical deposition for supercapacitor applications. Read the full text of the Article at 10.1002/celc.201500025.