bluuebunny/crossref_metadata_2025_split huggingface dataset:
Calculus of Variations
Authors: Roubíček Tomáš 
Published: March 2015

AbstractBasic general concepts and results from modern calculus of variations are presented both on an abstract level, based on nonlinear smooth, convex, or nonsmooth analysis on linear (namely Banach) spaces, and then on a concrete level of multidimensional variational problems on function (namely Sobolev) spaces leading to 2nd‐ or 4th‐order elliptic equations or systems. Beside static problems, also evolution problems are addressed, both for various variational principles and for recursive variational problems occuring after time discretisation. Concrete illustrative examples concern heat‐transfer problems, elasticity both at large and at small strains, micromagnetism, etc.
Cobalt(II)‐Catalyzed Electrophilic Alkynylation of 1,3‐Dicarbonyl Compounds To Form Polysubstituted Furans via π–π Activation
Authors: Roslan Irwan Iskandar , Sun Jiulong , Chuah Gaik‐Khuan , Jaenicke Stephan 
Published: March 2015

AbstractPolysubstituted furans were obtained with excellent yields via the electrophilic alkynylation of 1,3‐dicarbonyl compoundsws with phenyl‐ or ester‐substituted brominated alkynes. The reaction is catalyzed by the inexpensive and readily available catalyst, cobalt(II) chloride, and has a wide substrate scope. The C(sp)C(sp3) coupling occurs under mild conditions with short reaction times and does not require an inert atmosphere or ligands. It is proposed that the reaction proceeds through a chelation complex of cobalt(II) with the deprotonated 1,3‐dicarbonyl compound.magnified image
Gas–Liquid Segmented Flow Microfluidics for Screening Copper/TEMPO‐Catalyzed Aerobic Oxidation of Primary Alcohols
Authors: Vanoye Laurent , Pablos Mertxe , de Bellefon Claude , Favre‐Réguillon Alain 
Published: March 2015

AbstractAerobic oxidation using a combination of copper salts and 2,2,6,6‐tetramethylpiperidine N‐oxyl (TEMPO) represent useful tools for organic synthesis and several closely related catalyst systems have been reported. To gain further insights, these catalytic systems were evaluated in a gas–liquid segmented flow device. The improvement of oxygen mass transfer has a significant influence on the turnover‐limiting step. Hence, an improved catalytic system using copper(II) as copper source was implemented in a microreactor for the safe and efficient oxidation of primary alcohol.magnified image
One‐Step Synthesis of a [20]Silafullerane with an Endohedral Chloride Ion
Authors: Tillmann Jan , Wender Josef Heinrich , Bahr Ute , Bolte Michael , Lerner Hans‐Wolfram , Holthausen Max C. , Wagner Matthias 
Published: March 2015

AbstractSilicon analogues of the most prominent carbon nanostructures, namely, hollow spheroidals such as C60 and the fullerene family, have been unknown to date. Herein we show that discrete Si20 dodecahedra, stabilized by an endohedral guest and valence saturation, are accessible in preparative yields through a chloride‐induced disproportionation reaction of hexachlorodisilane in the presence of tri(n‐butyl)amine. X‐ray crystallography revealed that each silicon dodecahedron contains an endohedral chloride ion that imparts a net negative charge. Eight chloro substituents and twelve trichlorosilyl groups are attached to the surface of each cluster in a strictly regioregular arrangement, a thermodynamically preferred substitution pattern according to quantum‐chemical assessment. Our results demonstrate that the wet‐chemical self‐assembly of a complex, monodisperse Si nanostructure is possible under mild conditions starting from simple Si2 building blocks.
Preparation and properties of functionalized graphene/waterborne polyurethane composites with highly hydrophobic
Authors: Luo Xiaomin , Zhang Peng , Ren Jing , Liu Rui , Feng Jianyan , Ge Binghui 
Published: March 2015

ABSTRACTThe long‐chain functionalized graphene nanoplatelets (FGN) were functionalized by isophorone diisocyanate and then octadecylamine, the graphene functionalized/waterborne polyurethane (WPU) composites were prepared by solution mixture. The results showed that the FGN achieved good dispersion with exfoliated and intercalated nanostructure and strong interfacial adhesion with WPU, which made the nano–composites have a significant enhancement of thermal stability and mechanical properties at low FGN loadings. With 1.5% of FGN added, the tensile strength of the composites reached the maximum of 17 MPa, which improved by 41.6%, the water absorption of the composites is only 6.7%. With the incorporation of 2 wt % FGN, and the static contact angle of the composites reached to about 120°, showing the high hydrophobicity. At the same time, the volume resistivity of the composites was changed from 2.34 × 1012 Ω·cm to 3.77 × 109 Ω·cm. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42005.
Dynamic swelling behavior of interpenetrating polymer networks in response to temperature and pH
Authors: Slaughter Brandon V. , Blanchard Aaron T. , Maass Katie F. , Peppas Nicholas A. 
Published: March 2015

ABSTRACTTemperature responsive hydrogels based on ionic polymers exhibit swelling transitions in aqueous solutions as a function of shifting pH and ionic strength, in addition to temperature. Applying these hydrogels to useful applications, particularly for biomedical purposes such as drug delivery and regenerative medicine, is critically dependent on understanding the hydrogel solution responses as a function of all three parameters together. In this work, interpenetrating polymer network (IPN) hydrogels of polyacrylamide and poly(acrylic acid) were formulated over a broad range of synthesis variables using a fractional factorial design, and were examined for equilibrium temperature responsive swelling in a variety of solution conditions. Due to the acidic nature of these IPN hydrogels, usable upper critical solution temperature (UCST) responses for this system occur in mildly acidic environments. Responses were characterized in terms of maximum equilibrium swelling and temperature‐triggered swelling using turbidity and gravimetric measurements. Additionally, synthesis parameters critical to achieving optimal overall swelling, temperature‐triggered swelling, and sigmoidal temperature transitions for this IPN system were analyzed based on the fractional factorial design used to formulate these hydrogels. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42076.
Releasing property from surface polyion complex gel
Authors: Ajiro Hiroharu , Takemoto Yukie , Takemura Kazuya , Asoh Taka‐aki , Akashi Mitsuru 
Published: March 2015

ABSTRACTSurface polyion complex (sPIC) gels were prepared with a nonionic hydrogel interior core, composed of poly(N‐vinylformamide and poly(N‐vinylacetamide), and a chemically bounded polyion complex layer on the outer surface, composed of poly(vinylamine) and poly(acrylic acid). The gels were investigated as controlled drug release models based on electrostatic interactions depending on pH. Methylene blue and allura red were employed as cationic and anionic drug models, respectively, and resulted in the selective adsorption depending on pH conditions. Monovalent and multivalent anionic drug models, allura red and 1,3,6‐naphthalenetrisulfonate were observed for their releasing behavior from the sPIC gel. The results indicated that the multivalent anionic drug effectively controlled release depending on pH conditions. We further investigated sPIC gels regarding their ability to control the release of ionic molecules as a function of pH‐driven changes in electrostatic interactions. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42081.
Dynamic rheological behavior of reactively compatibilized polypropylene/polyamide 6 blending melts
Authors: Liao Hua‐yong , Zheng Lu‐yao , Hu Yong‐bing , Zha Xian‐jun , Xu Xiang , Wen Yan‐wei , Tao Guo‐liang , Liu Chun‐lin 
Published: March 2015

ABSTRACTThe dynamic rheological behavior is measured by small amplitude oscillatory shear on rotational rheometer for polypropylene/polyamide 6 (PP/PA6) blends compatibilized by a polypropylene grafted maleic anhydride (PP‐g‐MAH). Scanning electron microscope (SEM) results show that the PP/PP‐g‐MAH/PA6 (=100/6/40wt) is sea‐island structure, the PP/PP‐g‐MAH/PA6 (=100/6/60wt) blend is semi‐cocontinuous. Coarse PA6 zones can be observed when the weight ratio is 100/6/80. At low frequency the complex viscosity, dynamic modulus of the PP/PP‐g‐MAH/PA6 (PP/PP‐g‐MAH = 100/6wt) blends first increase then drop with the increase of PA6 weight content in the range of 0–100, the maximum value arrives at the weight content of 60. The Cole–Cole plots as well as the weighted relaxation spectra of the blends have a main arc and a tail when the weight ratio of PP/PP‐g‐MAH/PA6 is in the range of 100/6/20–100/6/60, but have different shapes when the weight ratio increases to 100/6/80 and 100/6/100. The possible reason is the weight ratio of 100/6/80 and 100/6/100 is close to the phase inversion point. In fitting the storage modulus data at low frequency, Palierne's model with two parameters interfacial tension and interfacial shear modulus is better than Bousmina's model. Palierne's model with only one parameter of interfacial tension can not fit the data well. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42091.
Degradation of photovoltaic backsheets: Comparison of the aging induced changes on module and component level
Authors: Knausz Marlene , Oreski Gernot , Eder Gabriele C. , Voronko Yuliya , Duscher Bernadette , Koch Thomas , Pinter Gerald , Berger Karl A. 
Published: March 2015

ABSTRACTIn reliability testing of components for PV modules an always remaining question is about material (in)compatibilities and synergistic effects and thus, how results of singly tested materials correlate with materials aged within PV modules. Testing of single materials would simplify sample preparation, reduce costs and offer more testing options. Therefore the main objective of this study was to compare the aging behavior of single backsheets with that of backsheets incorporated within PV modules. Four different types of backsheets were chosen, all of them comprising of polyethylene terephthalate (PET) core layers, but differing outer protection layers. Test modules using identical components, varying only in the type of backsheet used were produced and damp heat aged (85°C/85% RH ≤2000 h). The results revealed no influence of the PV module lamination on the thermal characteristics of the polymeric backsheets. Even after DH aging, differences between single and module laminated backsheets were negligible. Degradation effects of PET could be detected for all aged sheets by thermal analysis and were confirmed by tensile tests and rheological measurements. Thus, it can be stated that testing of single PET based backsheets under DH aging conditions is a practicable way to investigate the applicability of a new backsheet. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42093.
Leading change: Curriculum reform in graduate education in the biomedical sciences
Authors: Dasgupta Shoumita , Symes Karen , Hyman Linda 
Published: March 2015

AbstractThe Division of Graduate Medical Sciences at the Boston University School of Medicine houses numerous dynamic graduate programs. Doctoral students began their studies with laboratory rotations and classroom training in a variety of fundamental disciplines. Importantly, with 15 unique pathways of admission to these doctoral programs, there were also 15 unique curricula. Departments and programs offered courses independently, and students participated in curricula that were overlapping combinations of these courses. This system created curricula that were not coordinated and that had redundant course content as well as content gaps. A partnership of key stakeholders began a curriculum reform process to completely restructure doctoral education at the Boston University School of Medicine. The key pedagogical goals, objectives, and elements designed into the new curriculum through this reform process created a curriculum designed to foster the interdisciplinary thinking that students are ultimately asked to utilize in their research endeavors. We implemented comprehensive student and peer evaluation of the new Foundations in Biomedical Sciences integrated curriculum to assess the new curriculum. Furthermore, we detail how this process served as a gateway toward creating a more fully integrated graduate experience, under the umbrella of the Program in Biomedical Sciences. © 2015 by The International Union of Biochemistry and Molecular Biology, 43(2):126–132, 2015.
Development and application of an analytical method for curdione quantification in pregnant sprague–dawley rats by LC‐MS/MS
Authors: Meng Xiang , Zhang Ting , Li Ying , Pan Qi , Jiang Juan , Luo Yongwei , Chong Liming , Yang Yang , Xu Sichong , Zhou Li , Sun Zuyue 
Published: March 2015

AbstractThe vaginal administration route suffers from relatively low absorption efficiency, which may hinder the identification of the toxicokinetics of curdione in pregnant women. A sensitive analytical method for determining the plasma concentration of curdione was developed and applied in the determination of curdione in pregnant Sprague–Dawley rats as a simulated model. Glimepiride was used as an internal standard and chromatographic separation was achieved on a Capcell Pak C18 MGIII column. A gradient elution profile with 0.5% formic acid (A)–0.5% formic acid–acetonitrile (B) was selected as mobile phase. The selected reaction monitoring mode was used for quantification based on the target fragment ions m/z 237.2 to m/z 135.1 for curdione and m/z 491.3 to m/z 352.1 for the glimepiride. The standard curve was linear over the range of 0.5–500 ng/mL for curdione in rat plasma and yielded a consistent peak pattern, even at the lower limit of quantitation of 0.5 ng/mL. The retention times of curdione and IS were 6.55 and 6.59 min, respectively. The mean recovery of curdione in rat plasma was 95.5–101.1%. The intra‐day and inter‐day precisions were between 2.35 and 9.08%. This LC‐MS/MS method provides a simple and sensitive means for determining the plasma concentration. Copyright © 2015 John Wiley & Sons, Ltd.
LTA/Poly(1‐trimethylsilyl‐1‐propyne) Mixed‐Matrix Membranes for High‐Temperature CO2/N2 Separation
Authors: Fernández‐Barquín Ana , Casado‐Coterillo Clara , Palomino Miguel , Valencia Susana , Irabien Angel 
Published: March 2015

AbstractMixed‐matrix membranes (MMM) consisting of poly(1‐trimethylsilyl‐1‐propyne) (PTMSP) as continuous matrix and small‐pore LTA‐framework zeolites with Si/Al ratios from 1 (commercial zeolite A) to ∞ (ITQ‐29) as dispersed phase were prepared by solution casting. The thermal stability of the MMM is as high as that of glassy PTMSP polymer, whose high permeability is maintained even at increasing temperature. The effect of the Si/Al ratio in the zeolite fillers on the membrane performance is observed by the increasing CO2/N2 permselectivity of low‐Si/Al ratio zeolite A‐based membranes, in comparison with pure silica ITQ‐29. The performance of the LTA‐type zeolite‐PTMSP MMM was adjusted to the modified Maxwell model by estimating the chain immobilization factor and the interphase thickness as a function of temperature, Si/Al ratio, and zeolite loading.
High‐Performance Electrocatalysts for Oxygen Reduction Based on Nitrogen‐Doped Porous Carbon from Hydrothermal Treatment of Glucose and Dicyandiamide
Authors: Liu Xiaojun , Li Ligui , Zhou Weijia , Zhou Yucheng , Niu Wenhan , Chen Shaowei 
Published: March 2015

AbstractA synthetic method was developed for the preparation of N‐doped porous carbon through hydrothermal treatment at controlled temperatures by using glucose and dicyandiamide as precursors and ZnCl2 as an activation reagent. Nitrogen doping was quantitatively determined by using XPS measurements and identified in the forms of pyridinic, pyrrolic, graphitic, and pyridinic N+O−nitrogen atoms. Further structural analysis by using SEM, TEM, XRD, Raman, FTIR, and BET measurements showed that the N‐doped porous carbons exhibited a microcrystalline graphite structure and a high specific surface area up to 1000 m2 g−1. Electrochemical studies showed that the samples all exhibited a remarkable ORR catalytic activity in alkaline media, which was comparable to that of state‐of‐the‐art Pt/C catalysts, and the one prepared at 800 °C was found to be the best among the series with an onset potential of +0.96 V, almost complete reduction of oxygen to OH−, and superior methanol tolerance and cycling stability.
Highly Graphitic Clew‐Like Nanocarbons for Supercapacitors
Authors: Liu Tiantian , Liu Enhui , Ding Rui , Luo Zhenyu , Hu Tiantian , Li Zengpeng 
Published: March 2015

AbstractHighly graphitic clew‐like nanocarbons (HGCNs) are synthesized through a simple hydrothermal method followed by impregnation and catalytic graphitization at 900 °C, in which sucrose and nickel acetate are employed as the carbon source and nickel catalyst precursor, respectively. Transmission electron microscopy images clearly demonstrate that HGCN is composed of interconnected and curled carbon nanowires with sizes ranging from 10 to 25 nm, and these nanowires twist around each other to form clew‐like nanostructures. HGCNs combine the features of high specific surface area (≈691 m2 g−1), hierarchical micro‐/mesoporous architecture and a highly graphitic structure. The electrochemical measurements show that HGCNs present a low equivalent series resistance (ESR) of 0.53 Ω and a specific capacitance of 248 F g−1 at 0.5 A g−1 with 85 % retention even at a high current density of 5 A g−1, demonstrating that HGCNs provide favorable prospects in electrode materials for supercapacitors.
Tandem Gold/Silver‐Catalyzed Cycloaddition/Hydroarylation of 7‐Aryl‐1,6‐enynes to Form 6,6‐Diarylbicyclo[3.2.0]heptanes
Authors: Robertson Bradley D. , Brooner Rachel E. M. , Widenhoefer Ross A. 
Published: March 2015

AbstractMixtures of [{PCy2(o‐biphenyl)}AuCl] and AgSbF6 catalyze the tandem cycloaddition/hydroarylation of 7‐aryl‐1,6‐enynes with electron‐rich arenes to form 6,6‐diarylbicyclo[3.2.0]heptanes in good yield under mild conditions. Experimental observations point to a mechanism involving gold‐catalyzed cycloaddition followed by silver‐catalyzed hydroarylation of a bicyclo[3.2.0]hept‐1(7)‐ene intermediate.
Genetic variants in noncoding PIWI‐interacting RNA and colorectal cancer risk
Authors: Chu Haiyan , Xia Liping , Qiu Xiaonan , Gu Dongying , Zhu Linjun , Jin Jing , Hui Gaoyun , Hua Qiuhan , Du Mulong , Tong Na , Chen Jinfei , Zhang Zhengdong , Wang Meilin 
Published: March 2015

BACKGROUNDPIWI‐interacting RNAs (piRNAs), which are a novel type of identified small noncoding RNA (ncRNA), play a crucial role in germline development and carcinogenesis.METHODSBy systematically screening all known piRNAs, the authors identified 7 common single nucleotide polymorphisms (SNPs) in 9 piRNAs. Associations between these selected SNPs and the risk of colorectal cancer (CRC) were detected in a case‐control study. A quantitative real‐time polymerase chain reaction assay was used to evaluate messenger RNA (mRNA) expression levels of piR‐015551 and of the long ncRNA (lncRNA) LNC00964‐3 in 88 pairs of tissue samples.RESULTSThe assay revealed that reference SNP rs11776042 in piR‐015551 was significantly associated with a decreased risk of CRC in an additive model (P = .020). However, this protective effect was not significant after correction for multiple comparisons (test for the false discovery rate; P = .140). Furthermore, the authors observed that mRNA expression levels of LNC00964‐3 (an lncRNA that included the piR‐015551 sequence but not piR‐015551) were significantly lower in CRC tissues than in corresponding normal tissues (P = 1.5 × 10−5 for LNC00964‐3; P = .899 for piR‐015551). Correlation analysis revealed that piR‐015551 expression was positively correlated with expression levels of LNC00964‐3 (CRC tissues: r = 0.574, P = 5.13 × 10−9; normal tissues: r = 0.601, P = 5.76 × 10−10). Moreover, rs11776042 was not significantly correlated with mRNA expression levels of piR‐015551 or LNC00964‐3 (all P > .05).CONCLUSIONSThe current findings reveal the possibility that piR‐015551 may be generated from LNC00964‐3, which may be involved in the development of CRC. Cancer 2015;121:2044–2052. © 2015 American Cancer Society.
Improvements in the early death rate among 9380 patients with acute myeloid leukemia after initial therapy: A SEER database analysis
Authors: Percival Mary‐Elizabeth M. , Tao Li , Medeiros Bruno C. , Clarke Christina A. 
Published: March 2015

BACKGROUNDAcute myeloid leukemia (AML) is treated with conventional induction chemotherapy shortly after diagnosis for the majority of patients aged ≤65 years. A recent report suggested a substantial decline in the early, or 1‐month, mortality rate in patients treated on clinical trials over the past 2 decades. It is unknown whether a similar improvement has been observed in the general population.METHODSThe authors examined the 1‐month mortality rate in a large population‐based series of 9380 patients with AML who were aged ≤65 years and were diagnosed and treated with chemotherapy between 1973 and 2010.RESULTSA significant decline was observed in the 1‐month mortality rate from 18.7% among patients diagnosed from 1973 through 1977 (95% confidence interval [95% CI], 16.4%‐21.2%) to 5.8% for those diagnosed between 2008 and 2010 (95% CI, 4.5%‐7.6%) (P <.001). The median overall survival improved significantly from 6 months (95% CI, 5 months‐7 months) in 1973 to 1977 to 23 months (95% CI, 16 months‐20 months) in 2008 to 2010 (P <.001). Although age and geographic variation were found to significantly influence the 1‐month mortality for the period between 1973 and 1977, these differences in 1‐month mortality were no longer significant among patients with AML who were treated more recently (2008‐2010).CONCLUSIONSOver the past 4 decades, early mortality has become uncommon in younger patients (aged ≤65 years) with newly diagnosed AML undergoing induction chemotherapy. It is encouraging that the improvements noted in 1‐month mortality rate among a selective cohort of patients in clinical trials have also been observed in a population‐based analysis. Cancer 2015;121:2004–2012. © 2015 American Cancer Society.