bluuebunny/crossref_metadata_2025_split huggingface dataset:
Properties of polyetherimide/graphite composites prepared using ultrasonic twin‐screw extrusion
Authors: Zhong Jing , Isayev Avraam I. 
Published: September 2014

ABSTRACTThe dispersion of various graphites in polymers is a challenging problem limiting their potential use. To solve this problem, an ultrasound assisted twin‐screw extruder was developed and utilized to compound polyetherimide (PEI) with untreated nature graphite (UG), modified graphite (MG) and expanded graphite (EG) at concentrations up to 10 wt %. The effect of ultrasonic amplitude on rheological, mechanical and electrical properties of the PEI composites was investigated. Ultrasonic treatment of PEI/UG composites showed little effect on these properties. In contrast, ultrasonic treatment of PEI/MG and PEI/EG composites led to an increase of the storage (G′), loss (G″) moduli and complex viscosity and to a decrease of the damping characteristics. In particular, the PEI/5 wt %EG composite ultrasonically treated at an amplitude of 10 μm showed a 45% higher complex viscosity than the untreated composite at a frequency of 0.5 rad/s. Also, the PEI/5 wt % EG composite treated at an amplitude of 10 μm showed a reduction in the electrical volume resistivity by almost three orders of magnitude leading to a lower percolation threshold. The untreated and treated PEI/UG and PEI/MG composites did not show any percolation within all graphite concentrations studied, due to large size of particles of UG and MG and their strong agglomeration. The ultrasonic treatment showed slight effect on mechanical properties of all these composites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41397.
Differences in risk factors for second and third degree hypospadias in the national birth defects prevention study
Authors: Woud Sander Groen in 't , van Rooij Iris A.L.M. , van Gelder Marleen M.H.J. , Olney Richard S. , Carmichael Suzan L. , Roeleveld Nel , Reefhuis Jennita ,   the National Birth Defects Prevention Study
Published: September 2014

BackgroundHypospadias is a frequent birth defect with three phenotypic subtypes. With data from the National Birth Defects Prevention Study, a large, multi‐state, population‐based, case–control study, we compared risk factors for second and third degree hypospadias.MethodsA wide variety of data on maternal and pregnancy‐related risk factors for isolated second and third degree hypospadias was collected by means of computer‐assisted telephone interviews to identify potential etiological differences between the two phenotypes. Logistic regression was used to calculate odds ratios including a random effect by study center.ResultsIn total, 1547 second degree cases, 389 third degree cases, and 5183 male controls were included in our study. Third degree cases were more likely to have a non‐Hispanic black or Asian/Pacific Islander mother, be delivered preterm, have a low birth weight, be small for gestational age, and be conceived with fertility treatments than second degree cases and controls. Associations with both second and third degree hypospadias were observed for maternal age, family history, parity, plurality, and hypertension during pregnancy. Risk estimates were generally higher for third degree hypospadias except for family history.ConclusionMost risk factors were associated with both or neither phenotype. Therefore, it is likely that the underlying mechanism is at least partly similar for both phenotypes. However, some associations were different between second and third degree hypospadias, and went in opposite directions for second and third degree hypospadias for Asian/Pacific Islander mothers. Effect estimates for subtypes of hypospadias may be over‐ or underestimated in studies without stratification by phenotype. Birth Defects Research (Part A) 100:703–711, 2014. © 2014 Wiley Periodicals, Inc.
Structural, Functional, and Spectroscopic Characterization of the Substrate Scope of the Novel Nitrating Cytochrome P450 TxtE
Authors: Dodani Sheel C. , Cahn Jackson K. B. , Heinisch Tillmann , Brinkmann‐Chen Sabine , McIntosh John A. , Arnold Frances H. 
Published: September 2014

AbstractA novel cytochrome P450 enzyme, TxtE, was recently shown to catalyze the direct aromatic nitration of L‐tryptophan. This unique chemistry inspired us to ask whether TxtE could serve as a platform for engineering new nitration biocatalysts to replace current harsh synthetic methods. As a first step toward this goal, and to better understand the wild‐type enzyme, we obtained high‐resolution structures of TxtE in its substrate‐free and substrate‐bound forms. We also screened a library of substrate analogues for spectroscopic indicators of binding and for production of nitrated products. From these results, we found that the wild‐type enzyme accepts moderate decoration of the indole ring, but the amino acid moiety is crucial for binding and correct positioning of the substrate and therefore less amenable to modification. A nitrogen atom is essential for catalysis, and a carbonyl must be present to recruit the αB′1 helix of the protein to seal the binding pocket.
Ruthenium‐Catalyzed Alkoxycarbonylation of Alkenes with Paraformaldehyde as a Carbon Monoxide Substitute
Authors: Liu Qiang , Wu Lipeng , Jackstell Ralf , Beller Matthias 
Published: September 2014

AbstractThe first efficient use of paraformaldehyde in the alkoxycarbonylation of alkenes is reported. Using a combination of readily available [Ru3(CO)12] and PCy3 (Cy=cyclohexyl) as catalyst, industrially important esters are produced in good to high yield (up to 90 %) at relatively low temperature. This new method is applicable to a series of alkenes and alcohols. Moreover, the use of formaldehyde as the carbonyl source provides the potential to avoid both reliance on CO in carbonylation reactions, and the requirement for special high‐pressure reactors.
Fabrication of Palladium Membranes Supported on a Silicalite‐1 Zeolite‐Modified Alumina Tube for Hydrogen Separation
Authors: Guo Yu , Wu Hongmei , Zhou Lidai , Zhang Zhenbin , Liu Haiou , Zhang Xiongfu 
Published: September 2014

AbstractThin palladium membranes were fabricated on macroporous α‐Al2O3 tubes by electroless plating. The silicalite‐1 (Sil‐1) zeolite serving as intermediate and diffusion barrier layer was introduced to modify the surface roughness and pore size of the porous substrate and prevent the atomic interdiffusions of the metal elements between Pd layer and the support. The Pd composite membranes were studied by scanning electron microscopy (SEM), X‐ray diffraction (XRD), and electron probe microanalysis (EPMA), revealing that morphology and structure of the Sil‐1 layer significantly influence the Pd membrane preparation. Single‐gas permeation tests were carried out with gas H2 and N2 to determine the permeation performance of the membranes. The resulting membrane exhibited long‐term stability under hydrogen permeation.
Microwave Setup Design for Continuous Fine‐Chemicals Synthesis
Authors: Patil Narendra G. , Benaskar Faysal , Rebrov Evgeny V. , Meuldijk Jan , Hulshof† Lumbertus A. , Hessel Volker , Schouten Jaap C. 
Published: September 2014

AbstractA feasibility study in state‐of‐the‐art multi‐ and monomode microwave cavities was conducted to outline important functionalities necessary in a microwave setup for continuous fine‐chemicals synthesis. For multimode operation, the heating efficiency depends on the position as well as on the volume distribution of the load. For monomode operation, the heating efficiency does not depend on the axial position and has a maximum with respect to the load diameter. Based on this study, a microwave setup consisting of four cavities was designed and constructed. The setup provided a defined microwave field pattern and allowed focusing of the microwave power. A near‐uniform distribution of microwave energy in all four cavities of the setup was achieved at reduced grid to applicator losses.
Comparative Study on Thermodynamic Analysis of CO2 Utilization Reactions
Authors: Swapnesh Anang , Srivastava Vimal C. , Mall Indra D. 
Published: September 2014

AbstractThermodynamic analysis of dimethyl ether (DME) and methane synthesis from CO2 hydrogenation, and dry reforming of methane was performed using Gibbs free energy minimization. The effects of temperature, pressure, and feed composition on conversion, selectivity, and yield were investigated for each process. High pressure, high H2/CO2 ratio, and low temperature favored DME production. The yield of methane during CO2 methanation increased at lower temperature, higher pressure, and H2/CO2 ratio. The yield of synthesis gas improved at higher temperature. Comparison of the three processes demonstrated that the CO2 conversion was highest during CO2 methanation reaction if the fraction of CO2 mol in the feed was less than 0.3. Above this value in the feed, dry reforming allowed the highest CO2 conversion.
Sperm mixing in the polyandrous leaf‐cutting ant Acromyrmex echinatior
Authors: Stürup Marlene , Nash David R. , Hughes William O. H. , Boomsma Jacobus J. 
Published: September 2014

AbstractThe insemination of queens by sperm from multiple males (polyandry) has evolved in a number of eusocial insect lineages despite the likely costs of the behavior. The selective advantages in terms of colony fitness must therefore also be significant and there is now good evidence that polyandry increases genetic variation among workers, thereby improving the efficiency of division of labor, resistance against disease, and diluting the impact of genetically incompatible matings. However, these advantages will only be maximized if the sperm of initially discrete ejaculates are mixed when stored in queen spermathecae and used for egg fertilization in a “fair raffle.” Remarkably, however, very few studies have addressed the level of sperm mixing in social insects. Here we analyzed sperm use over time in the highly polyandrous leaf‐cutting ant Acromyrmex echinatior. We genotyped cohorts of workers produced either 2 months apart or up to over a year apart, and batches of eggs laid up to over 2 years apart, and tested whether fluctuations in patriline distributions deviated from random. We show that the representation of father males in both egg and worker cohorts does not change over time, consistent with obligatorily polyandrous queens maximizing their fitness when workers are as genetically diverse as possible.
Life history variation in Barents Sea fish: implications for sensitivity to fishing in a changing environment
Authors: Wiedmann Magnus A. , Primicerio Raul , Dolgov Andrey , Ottesen Camilla A. M. , Aschan Michaela 
Published: September 2014

Summary

Under exploitation and environmental change, it is essential to assess the sensitivity and vulnerability of marine ecosystems to such stress. A species' response to stress depends on its life history. Sensitivity to harvesting is related to the life history “fast–slow” continuum, where “slow” species (i.e., large, long lived, and late maturing) are expected to be more sensitive to fishing than “fast” ones. We analyze life history traits variation for all common fish species in the Barents Sea and rank fishes along fast–slow gradients obtained by ordination analyses. In addition, we integrate species' fast–slow ranks with ecosystem survey data for the period 2004–2009, to assess life history variation at the community level in space and time. Arctic fishes were smaller, had shorter life spans, earlier maturation, larger offspring, and lower fecundity than boreal ones. Arctic fishes could thus be considered faster than the boreal species, even when body size was corrected for. Phylogenetically related species possessed similar life histories. Early in the study period, we found a strong spatial gradient, where members of fish assemblages in the southwestern Barents Sea displayed slower life histories than in the northeast. However, in later, warmer years, the gradient weakened caused by a northward movement of boreal species. As a consequence, the northeast experienced increasing proportions of slower fish species. This study is a step toward integrating life history traits in ecosystem‐based areal management. On the basis of life history traits, we assess the fish sensitivity to fishing, at the species and community level. We show that climate warming promotes a borealization of fish assemblages in the northeast, associated with slower life histories in that area. The biology of Arctic species is still poorly known, and boreal species that now establish in the Arctic are fishery sensitive, which calls for cautious ecosystem management of these areas.
Electrochemical Characterization of Chemically Synthesized Polythiophene Thin Films: Performance of Asymmetric Supercapacitor Device
Authors: Patil B. H. , Patil S. J. , Lokhande C. D. 
Published: September 2014

AbstractPolythiophene (PT) thin films have been prepared by chemical bath deposition (CBD) method at room temperature (300 K) via oxidative polymerization of thiophene using ammonium peroxodisulfate (APS) as an oxidizing agent. Globular particulates of PT are deposited on the stainless steel and glass substrates. The morphology and chain structure of PT are studied using scanning electron microscopy (SEM) and Raman spectroscopy techniques, respectively. The electrochemical behavior of PT electrode is studied using cyclic voltammetry and galvanostatic chargedischarge studies. PT thin film shows maximum specific capacitance of 300 F g−1 at 5 mV s−1 in 0.1 M LiClO4/PC electrolyte. The asymmetric device formed with PT and graphite shows supercapacitive properties useful in the power applications.
A Highly Sensitive and Selective Enzymatic Biosensor Based on Direct Electrochemistry of Hemoglobin at Zinc Oxide Nanoparticles Modified Activated Screen Printed Carbon Electrode
Authors: Palanisamy Selvakumar , Karuppiah Chelladurai , Chen Shen‐Ming , Periakaruppan Prakash 
Published: September 2014

AbstractA sensitive enzymatic biosensor has been developed for the detection of hydrogen peroxide (H2O2), nitrite (${{\rm NO}{{- \hfill \atop 2\hfill}}}$) and trichloroacetic acid (TCA) by using hemoglobin (Hb) immobilized on activated screen printed carbon electrode (ASPCE) and zinc oxide (ZnO) composite. A pair of well defined redox peaks is observed with a heterogeneous electron transfer rate constant (Ks) of 5.27 s−1 for Hb at ASPCE/ZnO. The biosensor exhibits the detection of H2O2, TCA and ${{\rm NO}{{- \hfill \atop 2\hfill}}}$ in the concentration range of 0.5–129.5 µmol L−1, 2.5–72.5 mmol L−1 and 0.2–674 µmol L−1 with the detection limit of 0.083 µmol L−1, 0.12 mmol L−1 and 0.069 µmol L−1, respectively.
Spray‐Coated Polymer Solar Cells based on Low‐Band‐Gap Donors Processed with ortho‐Xylene
Authors: La Notte Luca , Polino Giuseppina , Ciceroni Claudio , Brunetti Francesca , Brown Thomas M. , Di Carlo Aldo , Reale Andrea 
Published: September 2014

AbstractThe use of low‐band‐gap polymer donors in the field of polymer solar cells (PSCs) allows to reduce the gap with other consolidated photovoltaic technologies because high conversion efficiencies can be achieved. Unfortunately, optimal performance is strongly correlated to the use of chlorinated solvents, known to be harmful in working conditions due to their toxicity towards environment and human health. For this reason, high‐performing PSCs have been deposited via small‐area techniques. We report on the use of a PBDTTT‐C‐T:PC70BM blend dissolved in the non‐chlorinated solvent ortho‐xylene for the deposition of spin‐coated and spray‐coated active layers in direct PSCs. An impressive conversion efficiency of 8 % is obtained for the spin‐coated blend, whereas the significant value of 4.4 % is achieved by using the spray‐coated blend. The work opens the way to the use of low‐band‐gap materials in spray coating, a non‐wasteful technique compatible with coating large areas.
Nutritional composition of “gari” analog produced from cassava (Manihot esculenta) and cocoyam (Colocasia esculenta) tuber
Authors: Bamidele Oluwaseun P. , Ogundele Femi G. , Ojubanire Basirat A. , Fasogbon Mofoluwaso B. , Bello Olayide W. 
Published: September 2014

AbstractPhysicochemical properties of gari analog produced from coprocessing of Cassava (Manihot esculenta Crantz) and Cocoyam (Colocasia esculenta) were investigated. Cassava tuber and cocoyam were coprocessed at different percentages before frying separately. Proximate composition, mineral content, antinutritional factors, and sensory evaluation of various samples were determined. The results showed that the moisture content of all the samples was in the same range (7.28 ± 0.30 to 7.78 ± 0.14%). The protein content (1.57 ± 0.14 to 4.43 ± 0.16), ash (1.89 ± 0.10 to 2.15 ± 0.30), and crude fiber (1.53 ± 0.50 to 2.19 ± 0.10%) showed a significant increase with increase in the level of cocoyam substitution. The fat and carbohydrate content decreased with an increase in cocoyam level. The mineral contents of the samples increased with an increase in cocoyam content with sample F having the highest value of potassium, followed by samples E and D (68 mg/100 g, 35 mg/100 g, and 24 mg/100 g). The antinutritional factors of all the samples were at very low concentration while samples B, C, and D competed favorably with sample A (control) in sensory evaluation. In conclusion, coprocessing of cassava and cocoyam improved the nutritional quality of the gari produced with high level of acceptance from the taste panelist.
Spline Regression in the Presence of Categorical Predictors
Authors: Ma Shujie , Racine Jeffrey S. , Yang Lijian 
Published: September 2014

SummaryWe consider the problem of estimating a relationship nonparametrically using regression splines when there exist both continuous and categorical predictors. We combine the global properties of regression splines with the local properties of categorical kernel functions to handle the presence of categorical predictors rather than resorting to sample splitting as is typically done to accommodate their presence. The resulting estimator possesses substantially better finite‐sample performance than either its frequency‐based peer or cross‐validated local linear kernel regression or even additive regression splines (when additivity does not hold). Theoretical underpinnings are provided and Monte Carlo simulations are undertaken to assess finite‐sample behavior; and two illustrative applications are provided. An implementation in R is available; see the R package ‘crs’ for details. Copyright © 2014 John Wiley & Sons, Ltd.
A Review: Natural Fiber Composites Selection in View of Mechanical, Light Weight, and Economic Properties
Authors: Ahmad Furqan , Choi Heung Soap , Park Myung Kyun 
Published: September 2014

AbstractIn this study, the properties and application of natural fiber composites in automobile industries are discussed. Natural fibers are replacing the synthetic fibers in the various parts of automobiles due to their lightweight, low‐cost, and environmental aspects. For centuries, natural fibers have been used for making baskets, clothing, and ropes. Now the trend is changing and natural fibers such as: jute, hemp, flax, and sisal fibers are making their ways especially into the components of automobiles. Comparisons of material indices for beam and panel structures were made to investigate the possibility of using natural fiber composites instead of conventional and non‐conventional materials.
Development of Proteinaceous Plywood Adhesive and Optimization of Its Lap Shear Strength
Authors: Mekonnen Tizazu H. , Mussone Paolo G. , Choi Phillip , Bressler David C. 
Published: September 2014

AbstractThe primary goal of this research was to develop a waste protein based adhesive, and to optimize its lap shear strength under dry and wet conditions using Taguchi method. The feedstock for this work was specified risk material (SRM) that is considered the tissue potentially at risk of containing misfolded prions. SRM was hydrolyzed in accordance with government approved techniques and modified with a resin system to develop a renewable adhesive platform. Eight of the nine formulated adhesives met the minimum dry shear strength requirement of urea formaldehyde type adhesive, and three of the formulations also met the soak shear strength requirement. This work demonstrates a general valorization platform for the utilization of animal waste protein as a renewable adhesive feedstock.
One‐Step In Situ Biosynthesis of Graphene Oxide–Bacterial Cellulose Nanocomposite Hydrogels
Authors: Si Hongjuan , Luo Honglin , Xiong Guangyao , Yang Zhiwei , Raman Sudha R. , Guo Ruisong , Wan Yizao 
Published: September 2014

Graphene oxide–bacterial cellulose (GO/BC) nanocomposite hydrogels with well‐dispersed GO in the network of BC are successfully developed using a facile one‐step in situ biosynthesis by adding GO suspension into the culture medium of BC. During the biosynthesis process, the crystallinity index of BC decreases and GO is partially reduced. The experimental results indicate that GO nanosheets are uniformly dispersed and well‐bound to the BC matrix and that the 3D porous structure of BC is sustained. This is responsible for efficient load transfer between the GO reinforcement and BC matrix. Compared with the pure BC, the tensile strength and Young's modulus of the GO/BC nanocomposite hydrogel containing 0.48 wt% GO are significantly improved by about 38 and 120%, respectively. The GO/BC nanocomposite hydrogels are promising as a new material for tissue engineering scaffolds.
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Die rätselhafte Kettenfontäne
Authors: Schlichting Hans Joachim , Ucke Christian 
Published: September 2014

AbstractEine aus einem erhöht stehenden Becher herausgleitende Kugelkette steigt wie eine Fontäne steil nach oben auf, bevor sie zu Boden fällt. Ursache ist die Tatsache, dass die Kette nicht beliebig stark gebogen werden kann. Dazu sind die Verbindungsstücke zwischen den einzelnen Kugeln zu kurz. Diese unscheinbare Eigenschaft hat zur Folge, dass die Kettenglieder beim senkrechten Hochheben, mit dem anderen Ende auf die Unterlage drücken und ihrerseits einen Impuls von der Unterlage erfahren. Sie stoßen sich gewissermaßen selbst ab, steigen nach oben auf, bevor sie einen Bogen formen und zum Boden fallen.
Einsteins Äquivalenzprinzip im quantenmechanischen Test
Authors: Schlippert Dennis , Rasel Ernst M. 
Published: September 2014

AbstractTrotz größter Bemühungen ist es bis heute nicht gelungen, Quantenmechanik und Allgemeine Relativitätstheorie zu einer geschlossenen Theorie der Quantengravitation zu vereinigen. Moderne Ansätze schließen eine Verletzung des Äquivalenzprinzips nicht mehr aus. Eines der bekanntesten Postulate dieses Prinzips ist die Universalität des freien Falls, wonach alle Körper unabhängig von ihrer Zusammensetzung in einem Gravitationsfeld gleich schnell fallen. Kürzlich ist es unserer Gruppe gelungen, dieses Prinzip mit einem Materiewellen‐Interferometer bis auf weniger als 6·10–7 zu bestätigen.
Wie sich aus Musik Energie gewinnen lässt
Authors: Knappmann Stephan 
Published: September 2014

AbstractDer Begriff Energy Harvesting beschreibt Module, die Energie aus der Umwelt “ernten” können. Seit Kurzem gibt es ein handliches Gerät, das die Energiegewinnung aus Schwingungen vermittelt. Dieses Energy Harvesting Kit vermittelt Kenntnisse in den Bereichen resonante Schwingungen und Elektromagnetismus und ermöglicht, den Unterricht im Bereich Naturwissenschaft und Technik durch aktuelle Themen aufzulockern und gleichzeitig vom Lehrplan vorgesehene Themen abzuarbeiten.
Weichmacher Wasser
Authors: Vilgis Thomas 
Published: September 2014

Abstract“Lätschige” Kartoffelchips sind kein Vergnügen. Sie krachen nicht mehr, ihre Textur ist weich und unappetitlich. Ursache ist der Wassergehalt der Chips, präziser die Wasseraktivität. Sie ist eine texturbestimmende Größe. Polare Wassermoleküle wirken dabei als “Weichmacher” in partiell getrockneten Lebensmitteln.