bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and characterization of a novel poly(ester‐urethane) containing short lactate sequences and PEG moieties
Authors: He Xuelei , Xiao Congming , Xu Jing 
Published: September 2012

AbstractA novel poly(ester‐urethane) with tailor‐made structure was prepared by using lactic acid (LA) as starting material through a combination of two facile common reactions. First, a diol was prepared via the esterification between LA and poly(ethylene glycol) (PEG) with low molecular weight. Subsequently, the poly(ester‐urethane) was synthesized through the addition polymerization of the LA‐based diol and toluene 2,4‐diisocyanate with 1,4‐butanediol as chain extender. The structure, morphology, and properties of intermediate and the poly(ester‐urethane) were analyzed with Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, gel permeation chromatography (GPC), X‐ray diffraction, differential scanning calorimetry, polarizing optical microscopy, and thermogravimetric analysis. The results indicated that the intermediate was a diol of conjugating quite short lactate sequences with PEG oligomer, and the structure of the poly(ester‐urethane) was as expected. The thermal transition, thermal decomposition temperature, and crystallinity of the polymer samples depended on the molecular size of PEG. In vitro degradation property of the poly(ester‐urethane) also relied on the molecular weight of PEG. The weight loss percentages varied from 11 to 36% after 12‐days immersing in phosphate‐buffer saline at 37°C. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Single‐step modified QuEChERS for determination of chlorothalonil in shallot (Allium ascalonicum) using GC‐μECD and confirmation via mass spectrometry
Authors: Rahman Md. Musfiqur , Park Jong‐Hyouk , Abd El‐Aty A. M. , Choi Jeong‐Heui , Bae Hey Ree , Yang Angel , Park Ki Hun , Shim Jae‐Han 
Published: September 2012

ABSTRACTA single extraction method was developed for chlorothalonil in shallot using gas chromatography with an electron capture detector (GC‐μECD). Samples were extracted with single‐step modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method using ethyl acetate as an extraction solvent. Significant matrix effects were observed, and the calibration curve was constructed from the matrix. The linearity of the analytical response across the studied range of concentrations (0.01–1.00 mg/L) was excellent, obtaining a correlation coefficient (r2) of 0.996. >0.996. Recovery studies were carried out on spiked shallot blank samples, at two concentration levels (0.4 and 2.0 mg/kg) with three replicates performed at each level. Mean recoveries of 97.2–104.9% with RSDs of 1.3–2.7% were obtained. The method is demonstrated to be suitable for the determination of chlorothalonil in shallot. The dissipation rates of chlorothalonil were described using first‐order kinetics, and its half‐life was 2.8 days. Based on the dissipation pattern of the pesticide residues, the pre‐harvest residue limit (PHRL) was also calculated. Residues were confirmed via mass spectrometry. Copyright © 2012 John Wiley & Sons, Ltd.
Predicting the Enantioselectivity of the Copper‐Catalysed Cyclopropanation of Alkenes by Using Quantitative Quadrant‐Diagram Representations of the Catalysts
Authors: Aguado‐Ullate Sonia , Urbano‐Cuadrado Manuel , Villalba Isabel , Pires Elísabet , García José I. , Bo Carles , Carbó Jorge J. 
Published: September 2012

AbstractWe present a new methodology to predict the enantioselectivity of asymmetric catalysis based on quantitative quadrant‐diagram representations of the catalysts and quantitative structure–selectivity relationship (QSSR) modelling. To account for quadrant occupation, we used two types of molecular steric descriptors: the Taft–Charton steric parameter (ν(Charton)) and the distance‐weighted volume (VW). By assigning the value of the steric descriptors to each of the positions of the quadrant diagram, we generated the independent variables to build the multidimensional QSSR models. The methodology was applied to predict the enantioselectivity in the cyclopropanation of styrene catalysed by copper complexes. The dataset comprised 30 chiral ligands belonging to four different oxazoline‐based ligand families: bis‐ (Box), azabis‐ (AzaBox), quinolinyl‐ (Quinox) and pyridyl‐oxazoline (Pyox). In the first‐order approximation, we generated QSSR models with good predictive ability (r2=0.89 and q2=0.88). The derived stereochemical model indicated that placing very large groups at two diagonal quadrants and leaving free the other two might be enough to obtain an enantioselective catalyst. Fitting the data to a higher‐order polynomial, which included crossterms between the descriptors of the quadrants, resulted in an improvement of the predicting ability of the QSSR model (r2=0.96 and q2=0.93). This suggests that the relationship between the steric hindrance and the enantioselectivity is non‐linear, and that bulky substituents in diagonal quadrants operate synergistically. We believe that the quantitative quadrant‐diagram‐based QSSR modelling is a further conceptual tool that can be used to predict the selectivity of chiral catalysts and other aspects of catalytic performance.
Preparation of Stable Low‐Oxidation‐State Group 14 Element Amidohydrides and Hydride‐Mediated Ring‐Expansion Chemistry of N‐Heterocyclic Carbenes
Authors: Al‐Rafia S. M. Ibrahim , McDonald Robert , Ferguson Michael J. , Rivard Eric 
Published: September 2012

AbstractVarious low oxidation state (+2) group 14 element amidohydride adducts, IPr⋅EH(BH3)NHDipp (E=Si or Ge; IPr=[(HCNDipp)2C:], Dipp=2,6‐iPr2C6H3), were synthesized. Thermolysis of the reported adducts was investigated as a potential route to Si‐ and Ge‐based clusters; however, unexpected transmetallation chemistry occurred to yield the carbene–borane adduct, IPr⋅BH2NHDipp. When a solution of IPr⋅BH2NHDipp in toluene was heated to 100 °C, a rare CN bond‐activation/ring‐expansion reaction involving the bound N‐heterocyclic carbene donor (IPr) transpired.
Origin of the SN2 Benzylic Effect: Contributions by π Delocalization and Field/Inductive Effects
Authors: Rawlings Robert E. , McKerlie Adam K. , Bates Daniel J. , Mo Yirong , Karty Joel M. 
Published: September 2012

AbstractHistorically, the SN2 benzylic effect is attributed to a conjugative stabilization between the phenyl ring and the reaction center in the transition state. However, recent papers have cast doubt on this explanation. We have therefore investigated the origin of the SN2 benzylic effect for two different gas‐phase SN2 reactions, F– + C6H5CH2F and Cl– + C6H5CH2Cl, by carrying out two separate computational methodologies on each system – a vinylogue extrapolation (VE) methodology and a block‐localized wavefunction (BLW) methodology. The contributions we examined were (1) delocalization involving the ring's π system, and (2) field/inductive effects of the ring. For the fluoride and chloride reactions, the VE methodology suggests that delocalization contributes to a lowering of the reaction's energy barrier by 3.1 and 1.7 kcal/mol, respectively, and the BLW calculations suggest that delocalization contributes to lowering the barrier by 3.65 and 5.47 kcal/mol, respectively. Both methodologies therefore agree that π delocalization is a significant contributor to the benzylic effect. Furthermore, the VE methodology indicates that field/inductive effects also contribute to lowering the barriers by 2.2 and 3.2 kcal/mol, suggesting that a separate repulsive interaction serves to increase the barrier by 1.5 and 3.3 kcal/mol, respectively.
White matter changes in primary dystonia determined by 2D distribution analysis of diffusion tensor images
Authors: Vo An , Eidelberg David , Uluǧ Aziz M. 
Published: September 2012

AbstractPurpose:To determine brain tissue affected by dystonia by making group comparison of parameter‐based diffusion tensor imaging (DTI) distributions of patients with control subjects. A 2D distribution analysis of mean diffusivity and fractional anisotropy index was used for modeling brain tissues according to the inherent diffusion characteristics.Materials and Methods:Seven affected carriers of the DYT1 dystonia mutation and eight healthy control subjects were imaged for a previous study. We employed a 2D distribution analysis of all the diffusion voxels and a four compartmental brain model for group comparison of the dystonia subjects and controls.Results:Our analysis showed disease involvement in the white matter of the patients. Excellent tissue characterization was achieved automatically using the 2D distribution analysis based on a physical brain model.Conclusion:This 2D analysis implicated white matter in dystonia and could be useful as a screening tool in diseases with unknown pathologies. J. Magn. Reson. Imaging 2013;37:59–66. © 2012 Wiley Periodicals, Inc.
Preparation and properties of biocomposites composed of sorbitol‐based epoxy resin, pyrogallol–vanillin calixarene, and wood flour
Authors: Shimasaki Toshiaki , Yoshihara Satoru , Shibata Mitsuhiro 
Published: September 2012

AbstractThe reaction of pyrogallol (PG) and vanillin (VN), both of which are derived from plant resources, in the presence of p‐toluenesulfonic acid gave PG–VN calixarene (PGVNC) mainly composed of guaiacyl pyrogallol[4]arene. After sorbitol polyglycidyl ether (SPE) was mixed with PGVNC in tetrahydrofuran at an optimized epoxy/hydroxy ratio 1/2.65, the obtained SPE/PGVNC solution was mixed with wood flour (WF), prepolymerized at 150°C, and subsequently compressed at 190°C for 3 h to give SPE–PGVNC/WF biocomposites with WF content 0–20 wt%. The tan δ peak temperature of SPE–PGVNC was 148.1°C, which was much higher than that of the SPE cured with petroleum‐based phenol novolac (SPE–PN) at an optimized epoxy/hydroxy ratio 1/1. Although tan δ peak temperature slightly decreased with increasing WF content, the storage moduli of the SPE–PGVNC/WF biocomposites in the rubbery state at more than 150°C were much higher than those of SPE–PGVNC and SPE–PN. Also, the tensile modulus and strength for SPE–PGVNC/WF increased with increasing WF content. Field emission‐scanning electron microscopy analysis of the biocomposites revealed that WF is tightly incorporated into the crosslinked epoxy resins. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers
Development of novel porous nasal scaffold using injection molding
Authors: Teng Ping‐Tun , Chern Ming‐Jyh , Shen Yung‐Kang , Chiang Yuh‐Chyun 
Published: September 2012

AbstractPorous scaffolds fabricated from biodegradable polymers have been widely used and play a vital role in tissue engineering andin situtissue reconstruction. This study presents a novel fabrication technique involving injection molding and conventional particulate leaching (IM/PL) to obtain the L‐shaped nasal scaffold for rhinoplasty. The results indicate that the porous nasal scaffold made by the IM/PL method shows the acceptable biocompatibility and degradation. The nasal scaffold may degrade well after surgery and the cartilage tissue may grow well in it. This IM/PL technique may replace the traditional artificial silicone filler and reduce the surgery cost. POLYM. ENG. SCI. 2013. © 2012 Society of Plastics Engineers
Analytic formalism for current crowding in light emitting diodes
Authors: Lee Kyu‐Seok 
Published: September 2012

AbstractThis paper presents an analytic approach to simulating current crowding (CC) in light‐emitting diodes with parallel p‐ and n‐contacts. The electrical potential difference across the p–i–n layers is derived from the Laplace equation, whereas the current density through the p–i–n layers is obtained from the current density – voltage relation of a single‐diode model. Since these two properties influence each other, they are calculated iteratively. It is found that CC depends on the applied voltage (or the average current density), the sheet resistances of the p‐ and the n‐contact layers, the width of the active region, and the specific series resistance and ideality factor of the p–i–n layers.
The predictability of precipitation episodes during the West African dry season
Authors: Davis Jenny , Knippertz Peter , Fink Andreas H. 
Published: September 2012

AbstractPrecipitation episodes in tropical West Africa (7–15°N, 10°W–10°E) during the dry season from November to March are rare, but can have significant impacts on human activities reaching from greening of pastures to spoiling harvests and health implications. Previous work has shown a link between these unseasonal rainfalls and extratropical disturbances via a decrease of surface pressure over the Sahara/Sahel and a subsequent inflow of moist air from the Gulf of Guinea. This paper supports the previously stated hypothesis that the extratropical influence leads to a high rainfall predictability through a careful analysis of operational 5 day forecasts from the European Centre for Medium‐Range Weather Forecasts' (ECMWF) ensemble prediction system (EPS), which are evaluated using Global Precipitation Climatology Project (GPCP) and Tropical Rainfall Measuring Mission (TRMM) precipitation estimates for the 11 dry seasons 1998/99‐2008/09. The long‐term regional average of ensemble‐mean precipitation lies between the two observational datasets, with GPCP being considerably wetter. Temporal correlations between the ensemble mean and observations are 0.8. Standard probabilistic evaluation methods such as reliability and relative operating characteristic (ROC) diagrams indicate remarkably good reliability, sharpness and skill across a range of precipitation thresholds. However, a categorical verification focusing on the most extreme ensemble mean values indicates too many false alarms. Despite the considerable observational uncertainty the results show that the ECMWF EPS is capable of predicting winter rainfall events in tropical West Africa with good accuracy, at least on regional spatial and synoptic time‐scales, which should encourage West African weather services to capitalize more on the valuable information provided by ensemble prediction systems during the dry season. Copyright © 2012 Royal Meteorological Society
In situmeasurement using FBGs of process‐induced strains during curing of thick glass/epoxy laminate plate: experimental results and numerical modelling
Authors: Nielsen Michael Wenani , Schmidt Jacob Wittrup , Hattel Jesper Henri , Andersen Tom Løgstrup , Markussen Christen Malte 
Published: September 2012

ABSTRACTFor large composite structures, such as wind turbine blades, thick laminates are required to withstand large in‐service loads. During the manufacture of thick laminates, one of the challenges met is avoiding process‐induced shape distortions and residual stresses. In this paper, embedded fibre Bragg grating sensors are used to monitor process‐induced strains during vacuum infusion of a thick glass/epoxy laminate. The measured strains are compared with predictions from a cure hardening instantaneous linear elastic (CHILE) thermomechanical numerical model where different mechanical boundary conditions are employed. The accuracy of the CHILE model in predicting process‐induced internal strains, in what is essentially a viscoelastic boundary value problem, is investigated. A parametric study is furthermore performed to reveal the effect of increasing the laminate thickness. The numerical model predicts the experimental transverse strains well when a tied boundary condition at the tool/part interface is used and the tool thermal expansion is taken into account. However, the CHILE approach is shown to overestimate residual strains after demoulding because of the shortcomings of the model in considering viscoelastic effects. The process‐induced strain magnitude furthermore increases when the laminate thickness was increased, owing mainly to a decrease in through‐thickness internal transverse stresses. Copyright © 2012 John Wiley & Sons, Ltd.
Modeling, simulation and control of a wind turbine with a hydraulic transmission system
Authors: Skaare Bjørn , Hörnsten Bo , Nielsen Finn Gunnar 
Published: September 2012

ABSTRACTA complete mathematical model of a hydraulic transmission concept for use in wind turbines is presented. The hydraulic system transfers the power from the nacelle to ground level. The main focus has been to develop a model that takes into account the most important dynamics affecting the wind turbine and the hydraulic transmission system involved, such that the model can be used to analyze the dynamic feasibility of a hydraulic transmission concept. Further, dynamic analysis of a hydraulic transmission system for wind turbines is investigated. The nonlinear dynamic model is developed in MATLAB Simulink. Analytical calculation of natural periods of a linearized model corresponds well with simulations of the overall system.A valve control system is proposed to reduce pressure and power fluctuations at operation both below and above the rated wind speed for the wind turbine. Further, a blade pitch control system based on an aerodynamic power estimator is proposed for operation above the rated wind speed.System simulations for one case below and one case above the rated wind speed show that the dynamic response of the overall system is stable and that the wind turbine variables are within typical ranges for conventional variable speed wind turbines with mechanical transmission. Copyright © 2012 John Wiley & Sons, Ltd.
Ignoring ecological demands masks the real effect of urbanization: a case study of ground‐dwelling spiders along a rural–urban gradient in a lowland forest in Hungary
Authors: Horváth Roland , Magura Tibor , Tóthmérész Béla 
Published: September 2012

AbstractWe studied ground‐dwelling spiders along a rural–suburban–urban forest gradient representing increasing human disturbance using pitfall traps. We tested four known and two novel hypotheses: (1) increasing disturbance hypothesis (species richness is decreasing by disturbance); (2) matrix species hypothesis (the richness of open‐habitat species is increasing by disturbance); (3) opportunistic species hypothesis (the richness of generalist species is increasing by disturbance); and (4) habitat specialist hypothesis (the number of the forest specialist species is decreasing by disturbance). As a consequence of urbanization, urban forests become drier and more open; thus, according to the new hypotheses, the number of (5) xerophilous species and (6) light‐preferring species are increasing in the urban area. Our result did not support the increasing disturbance hypothesis, as the overall species richness increased from the rural sites to the urban ones. As predicted, the number of both the open‐habitat and the generalist species increased towards the urban sites. The number of forest specialist species was higher in the suburban area than in the rural and urban area. Both xerophilous and light‐preferring species were the most numerous in the urban area, supporting the xerophilous species and the light‐preferring species hypotheses. Canonical correspondence analysis showed that the forest specialist species associated with the rural sites with higher amounts of decaying woods and more herbs or with the suburban sites with higher cover of leaf litter and higher relative humidity. Two generalist species and one open‐habitat species were characteristic of urban sites with higher ground surface and air temperature.
ON THE EXISTENCE OF NONINNER AUTOMORPHISMS OF ORDER TWO IN FINITE 2-GROUPS
Authors: JAMALI A. R. , VISEH M. 
Published: September 2012

AbstractIn this paper we prove that every nonabelian finite 2-group with a cyclic commutator subgroup has a noninner automorphism of order two fixing either Φ(G) or Z(G) elementwise. This, together with a result of Peter Schmid on regular p-groups, extends our result to the class of nonabelian finite p-groups with a cyclic commutator subgroup.
Musculoskeletal Injuries Among Victims of the Battagram, Pakistan Earthquake in October 2005
Authors: Kaim Khani Ghulam Mustafa , Baig Akhtar , Humail Mujahid , Memon Manzoor , Quarashi M.A. 
Published: September 2012

AbstractObjectiveThis study was conducted to assess the type, pattern, and severity of musculoskeletal injuries, as well as the type of simple orthopedic surgical procedures, that can be performed at the site of a disaster.MethodsThis was a cross-sectional study conducted in Battagram, located in the North West Frontier Province of Pakistan after the October 2005 earthquake. Researchers arrived in the affected area during the second week after the earthquake, and remained there for one week. During this period, patients were received from distant areas of the district. These patients were admitted to a tent hospital because the district headquarters hospital was completely damaged. Those requiring orthopedic surgical intervention or closed manipulation and plaster of paris casts were included in the study.ResultsOf 110 patients, 61 were female and 49 were male, and 140 bones were involved. In this series, 92 fractures were closed, while 48 were open. A total of 67.3% of the patients were <40 years of age. The tibia was involved in 32.1% of cases and the femur 16.4%. No cases of compartment syndrome were found. Wound debridement was performed in 35 cases. An external fixator was applied to 10 cases of open tibia fractures. Four humerus fractures and a fracture to the radius and ulna were fixed with the Rashnail method. One open femur fracture was repaired with external fixation. Pre- and post-operative antibiotics were administered in all cases. Thirty patients sustained injuries in addition to orthopedic trauma: 13 vertebral injuries, eight head injuries, six fractured ribs, three blunt injuries to the abdomen, and 10 significant soft tissues injuries without bony involvement.ConclusionsAfter the earthquake in Battagram, young persons, especially females, were prone to orthopedic injuries, mainly involving the extremities. A comprehensive disaster plan would have helped to manage these emergencies, and further experience is needed for on-site surgical interventions.Kaim KhaniGM, BaigA, HumailM, MemonM, QuarashiMA. Musculoskeletal injuries among victims of the Battagram, Pakistan earthquake in October 2005. Prehosp Disaster Med.2012;27(5):1-3.
Haline hurricane wake in the Amazon/Orinoco plume: AQUARIUS/SACD and SMOS observations
Authors: Grodsky Semyon A. , Reul Nicolas , Lagerloef Gary , Reverdin Gilles , Carton James A. , Chapron Bertrand , Quilfen Yves , Kudryavtsev Vladimir N. , Kao Hsun‐Ying 
Published: September 2012

At its seasonal peak the Amazon/Orinoco plume covers a region of 106 km2in the western tropical Atlantic with more than 1 m of extra freshwater, creating a near‐surface barrier layer (BL) that inhibits mixing and warms the sea surface temperature (SST) to >29°C. Here new sea surface salinity (SSS) observations from the Aquarius/SACD and SMOS satellites help elucidate the ocean response to hurricane Katia, which crossed the plume in early fall, 2011. Its passage left a 1.5 psu high haline wake covering >105 km2 (in its impact on density, the equivalent of a 3.5°C cooling) due to mixing of the shallow BL. Destruction of this BL apparently decreased SST cooling in the plume, and thus preserved higher SST and evaporation than outside. Combined with SST, the new satellite SSS data provide a new and better tool to monitor the plume extent and quantify tropical cyclone upper ocean responses with important implications for forecasting.