bluuebunny/crossref_metadata_2025_split huggingface dataset:
A logistic kinetic model for isothermal and nonisothermal cure reactions of thermosetting polymers
Authors: López‐Beceiro Jorge , Fontenot Sean A. , Gracia‐Fernández Carlos , Artiaga Ramón , Chartoff Richard 
Published: March 2014

ABSTRACTA model describing the low‐temperature crystallization kinetics observed for thermoplastic polymers from the melt by differential scanning calorimetry (DSC) was shown to accurately predict the cooling curves as a function of time and temperature. The model was successful for treating data for several cooling rates as well as for isothermal DSC data. In this article, we extended the model to cure reactions of thermosetting polymers. The parameters representing lower and upper exotherm reference temperatures in crystallization events have a different meaning for curing events. Thus, the model was modified to account for this change of context. The new model was tested for exothermic reactions of a Hysol® FP4527 epoxy adhesive system using data from DSC ramp heating experiments at several heating rates and also from isothermal experiments. Good fits were obtained for all the varied experimental conditions. The model made use of three fitting parameters with physical significance: a lower critical temperature (Tc) an activation energy (Eb), and a reaction order (τ + 1). Additionally, to complete the kinetic fitting, the dependence of the time to reach the reaction peak maximum for isothermal cure was considered. That dependence was found to follow a more simple model which is formally equivalent to that observed in isothermal crystallization, and which makes use of two parameters related to the limits of the temperature range in which the polymerization may occur. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40670.
Melamine formaldehyde/polyvinyl alcohol composite fiber: Structure and properties manipulated by hydroxymethylation degree
Authors: Xu Weixing , Dong Shujuan , Yu Cihang , Yan Xiang , Xu Jianjun , Jiang Mengjin 
Published: March 2014

ABSTRACTComposite fibers made of different hydroxymethylation degree (HMD) melamine formaldehyde (MF) resins and polyvinyl alcohol were prepared by wet spinning. The structures of MF resins and composite fibers were studied using Fourier transform infrared spectrometer, optical microscope, scanning electron microscope, differential scanning calorimetry, X‐ray diffraction, and Kjeldahl. The fibers' mechanical properties, fire retardant properties, softening point in hot water, and thermal stability were also tested. Results show that with the increase of HMD, the compatibility between MF and PVA gets better; the breaking strength and thermal stability of the fibers increase, while the nitrogen‐loss rate, the elongation at break, and SP decrease. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40678.
Effect of gas permeation temperature and annealing procedure on the performance of binary and ternary mixed matrix membranes of polyethersulfone, SAPO‐34, and 2‐hydroxy 5‐methyl aniline
Authors: Oral Edibe Eda , Yilmaz Levent , Kalipcilar Halil 
Published: March 2014

AbstractThis study investigated the effect of annealing time and temperature on gas separation performance of mixed matrix membranes (MMMs) prepared from polyethersulfone (PES), SAPO‐34, and 2‐hydroxy 5‐methyl aniline (HMA). A postannealing period at 120°C for a week extensively increased the reproducibility and stability of MMMs, but for pure PES membranes no post‐annealing was necessary for stable and reproducible performance. The effect of operation temperature was also investigated. The permeabilities of H2, CO2, and CH4 increased with increasing permeation temperature from 35°C to 120°C, yet CO2/CH4 and H2/CH4 selectivities decreased. PES/SAPO‐34/HMA ternary and PES/SAPO‐34 binary MMMs exhibited the highest ideal selectivity and permeability values at all temperatures, respectively. For H2/CO2 pair, when temperature increased from 35°C to 120°C, selectivity increased from 3.2 to 4.6 and H2 permeability increased from 8 to 26.5 Barrer for ternary MMM, demonstrating the advantage of using this membrane at high temperatures. The activation energies were in the order of CH4 > H2 > CO2 for all membranes. PES/SAPO‐34/HMA membrane had activation energies higher than that of PES/SAPO‐34 membrane, suggesting that HMA acts as a compatibilizer between the two phases. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40679.
Coordination‐Driven Hierarchical Assembly of Silver Nanoparticles on MoS2 Nanosheets for Improved Lithium Storage
Authors: Pan Long , Liu Yi‐Tao , Xie Xu‐Ming , Zhu Xiao‐Dong 
Published: March 2014

AbstractWe report a novel strategy for the hierarchical assembly of Ag nanoparticles (NPs) on MoS2 nanosheets through coordination by using a multifunctional organic ligand. The presence of Ag NPs on the surface of MoS2 nanosheets inhibits their agglomeration, thereby providing increased interlayer spacing for easy Li+ ion intercalation. Such a unique hybrid architecture also ensures sufficient percolation pathways on the whole surface of the MoS2 nanosheets. Moreover, the high rigidity and low deformability of the Ag NPs effectively preserve the hybrid architecture during the charge–discharge process, which translates into a high cycle stability. A prominent synergistic effect between MoS2 and Ag is witnessed. When the Ag content is only 5 wt %, the Ag–MoS2 hybrid delivers a reversible capacity as high as 920 mA h g−1 at a current density of 100 mA g−1, making the Ag–MoS2 hybrid an attractive candidate for next‐generation LIBs.
Corncob hydrolysate, an efficient substrate for Monascus pigment production through submerged fermentation
Authors: Zhou Zhongxin , Yin Zheng , Hu Xiaoqing 
Published: March 2014

AbstractMonascus pigment has traditionally been produced by the fermentation of Monascus using rice powder or glucose as a culture substrate. Submerged fermentation can produce stable Monascus pigment yield and control the accumulation of the by‐product, citrinin, which can then be more easily removed. To reduce the cost of Monascus submerged fermentation, the feasibility of corncob hydrolysate as an alternative substrate was investigated. Results showed that, when compared with a conventional glucose medium, the corncob hydrolysate medium produced an equivalent pigment yield without stimulating citrinin accumulation. Furthermore, the corncob hydrolysate medium and cultivation conditions were optimized to enhance pigment production and decrease citrinin synthesis. When Monascus sp. was cultured under dark conditions in the presence of caprylic acid, pigment production was increased to 25.8 ± 0.8 UA500/mL, which was higher than that achieved in a glucose medium (24.0 ± 0.9 UA500/mL), and those obtained in previously reported Monascus submerged fermentations using the same yield unit; on the other hand, citrinin accumulation was decreased to 26.2 ± 1.9 µg/L, which was significantly lower than that generated in the glucose control (44.3 ± 2.2 µg/L) and in those previously reported fermentations. Thus, corncob hydrolysate was proved to be an efficient alternative substrate for Monascus pigment production through submerged fermentation, which showed significant advantages over a conventional glucose substrate.
Hysteretic Spin Crossover above Room Temperature and Magnetic Coupling in Trinuclear Transition‐Metal Complexes with Anionic 1,2,4‐Triazole Ligands
Authors: Gómez Verónica , Benet‐Buchholz Jordi , Martin Eddy , Galán‐Mascarós J. R. 
Published: March 2014

AbstractThe reaction of 4‐(1,2,4‐triazol‐4‐yl)ethanesulfonate (L) with Zn2+, Cu2+, Ni2+, Co2+, and Fe2+ gave a series of analogous neutral trinuclear complexes with the formula [M3(μ‐L)6(H2O)6] (1–5). These compounds were characterized by single‐crystal X‐ray diffraction, thermogravimetry, and elemental analysis. The magnetic properties of compounds 2–5 were studied. Complexes 2–4 show weak antiferromagnetic superexchange, with J values of −0.33 (2), −9.56 (3), and −4.50 cm−1 (4) (exchange Hamiltonian H=−2 J (S1S2+S2S3)). Compound 5 shows two additional crystallographic phases (5 b and 5 c) that can be obtained by dehydration and/or thermal treatment. These three phases exhibit distinct magnetic behavior. The Fe2+ centers in 5 are in high‐spin (HS) configuration at room temperature, with the central one exhibiting a non‐cooperative gradual spin transition below 250 K with T1/2=150 K. In 5 b, the central Fe2+ stays in its low‐spin (LS) state at room temperature, and cooperative spin transition occurs at higher temperatures and with the appearance of memory effect (T1/2↑=357 K and T1/2↓=343 K). In the case of 5 c, all iron centers remain in their HS configuration down to very low temperatures, with weak antiferromagnetic coupling (J=−1.16 cm−1). Compound 5 b exhibits spin transition with memory effect at the highest temperature reported, which matches the remarkable features of coordination polymers.
Cooperative Effect of Two Metals: CoPd(OAc)4‐Catalyzed CH Amination and Aziridination
Authors: Huang Guan‐Hao , Li Jian‐Min , Huang Jing‐Jyun , Lin Jyun‐Dai , Chuang Gary Jing 
Published: March 2014

AbstractThe first Co/Pd‐cocatalyzed intramolecular CH amination and aziridination reactions were developed. Sulfamate esters were converted to oxathiazinanes by using CoPd(OAc)4 as catalyst and PhI(OAc)2 as oxidant. The mutual presence of both Co and Pd is crucial for the catalytic activity. This combination of two metals with simple acetate ligands provides an economical alternative to the Rh‐catalyzed insertion of nitrenoids into CH bonds.
Magnetic Coupling and Optical Properties of the S6‐Dodecakis(trifluoromethyl)fullerene Radical Anions in the Layered Salt (PPN+)[C60(CF3)12.−]
Authors: Konarev Dmitri V. , Romanova Natalia A. , Panin Roman A. , Goryunkov Alexey A. , Troyanov Sergey I. , Lyubovskaya Rimma N. 
Published: March 2014

AbstractPoly(trifluoromethyl)fullerene S6‐C60(CF3)12 was reduced by sodium fluorenone ketyl in the presence of (PPN)Cl (PPN=bis(triphenylphosphine)iminium) to afford the salt (PPN)[C60(CF3)12] (1), which contains C60(CF3)12.− radical anions. In the crystal structure of 1, C60(CF3)12.− layers alternate with the PPN+ cations. There are short F⋅⋅⋅F contacts between C60(CF3)12.− radical anions within the layers but no C⋅⋅⋅C contacts. DFT calculations revealed that the negative charge on C60(CF3)12.− is distributed mainly between sp2 carbon and fluorine atoms, whereas spin density is localized mainly on the fullerene‐cage sp2 carbon atoms. IR and UV/Vis/NIR spectra in the solid state and solution showed characteristic changes relative to those of neutral S6‐C60(CF3)12 due to the formation of radical anions. The solid‐state electronic spectrum of 1 exhibits a single broad band at 738 nm attributed to C60(CF3)12.−. Crystals of 1 show a narrow EPR signal with g=2.0025 (ΔH=0.45 mT) at 300 K. The temperature dependence of the integral intensity follows the Curie–Weiss law with a negative Weiss temperature of −11.8 K (30–300 K) indicating antiferromagnetic interaction of spins. This dependence was approximated by the Heisenberg model for one‐dimensional chains of antiferromagnetically interacting spins with exchange interaction J/kB=−9.1 K. It was assumed that magnetic interaction between the C60(CF3)12.− spins in the layers is mediated by short F⋅⋅⋅F contacts.
Structural Diversity in Multinuclear PdII Assemblies that Show Low‐Humidity Proton Conduction
Authors: Samanta Dipak , Mukherjee Partha Sarathi 
Published: March 2014

AbstractSystematic investigation on synergetic effects of geometry, length, denticity, and asymmetry of donors was performed through the formation of a series of uncommon PdII aggregates by employing the donor in a multicomponent self‐assembly of a cis‐blocked 90° PdII acceptor and a tetratopic donor. Some of these assemblies represent the first examples of these types of structures, and their formation is not anticipated by only taking the geometry of the donor and the acceptor building units into account. Analysis of the crystal packing of the X‐ray structure revealed several H bonds between the counteranions (NO3−) and water molecules (OH⋅⋅⋅ON). Moreover, H‐bonded 3D‐networks of water are present in the molecular pockets, which show water‐adsorption properties with some variation in water affinity. Interestingly, these complexes exhibit proton conductivity (1.87×10−5–6.52×10−4 Scm−1) at 296 K and low relative humidity (ca. 46 %) with activation energies of 0.29–0.46 eV. Moreover, the conductivities further increase with the enhancement of humidity. The ability of these assemblies to exhibit proton‐conducting properties under low‐humidity conditions makes these materials highly appealing as electrolytes in batteries and in fuel‐cell applications.
Freezing Capture of Polymorphic Aggregates of Bolaamphiphilic L‐Valine‐Based Molecular Hydrogelators
Authors: Nebot Vicent J. , Díaz‐Oltra Santiago , Smets Johan , Fernández Prieto Susana , Miravet Juan F. , Escuder Beatriu 
Published: March 2014

AbstractNanostructured xerogels have been prepared by the freeze‐drying of hydrogels and aggregates formed by bolaamphiphilic L‐valine derivatives after aging under different environmental conditions. A wide variety of shapes and sizes has been achieved by a simple methodology. These nanostructures have been studied by SEM and WAXD and a dramatic influence of structural flexibility on the kinetics of aggregation has been observed. Such flexibility and a modulation of the hydrophobic effect have shown a profound influence in the packing of these compounds and revealed a high degree of polymorphism.
Design, Synthesis and Bioevaluation of an EphA2 Receptor‐Based Targeted Delivery System
Authors: Barile Elisa , Wang Si , Das Swadesh K. , Noberini Roberta , Dahl Russell , Stebbins John L. , Pasquale Elena B. , Fisher Paul B. , Pellecchia Maurizio 
Published: March 2014

AbstractBecause of its overexpression in a range of solid tumors, the EphA2 receptor is a validated target for cancer therapeutics. We recently described a new targeted delivery system based on specific EphA2‐targeting peptides conjugated with the chemotherapeutic agent paclitaxel. Here, we investigate the chemical determinants responsible for the stability and degradation of these agents in plasma. Introducing modifications in both the peptide and the linker between the peptide and paclitaxel resulted in drug conjugates that are both long‐lived in rat plasma and that markedly decrease tumor size in a prostate cancer xenograft model compared with paclitaxel alone treatment. These studies identify critical rate‐limiting degradation sites on the peptide–drug conjugates, enabling the design of agents with increased stability and efficacy. These results provide support for our central hypothesis that peptide–drug conjugates targeting EphA2 represent an innovative and potentially effective strategy to selectively deliver cytotoxic drugs to cancer cells.
Feasibility, efficacy, and adverse effects of outpatient antibacterial prophylaxis in children with acute myeloid leukemia
Authors: Inaba Hiroto , Gaur Aditya H. , Cao Xueyuan , Flynn Patricia M. , Pounds Stanley B. , Avutu Viswatej , Marszal Lindsay N. , Howard Scott C. , Pui Ching‐Hon , Ribeiro Raul C. , Hayden Randall T. , Rubnitz Jeffrey E. 
Published: March 2014

BACKGROUNDIntensive chemotherapy for pediatric acute myeloid leukemia incurs the risk of infectious complications, but the benefits of antibiotic prophylaxis remain unclear.METHODSIn the current study, among 103 children treated on the AML02 protocol between October 2002 and October 2008 at St. Jude Children's Research Hospital, the authors retrospectively assessed the effect of antibiotic prophylaxis on the frequency of febrile neutropenia, clinically or microbiologically confirmed infections (including bacteremia), and antibiotic resistance, as well as on the results of nasal and rectal surveillance cultures. Initially, patients received no prophylaxis or oral cephalosporin (group A). The protocol was then amended to administer intravenous cefepime alone or intravenous vancomycin plus either oral cephalosporin, oral ciprofloxacin, or intravenous cefepime (group B).RESULTSThere were 334 infectious episodes. Patients in group A had a significantly greater frequency of documented infections and bacteremia (both P < .0001) (including gram‐positive and gram‐negative bacteremia; P = .0003 and .001, respectively) compared with patients in group B, especially viridans streptococcal bacteremia (P = .001). The incidence of febrile neutropenia without documented infection was not found to be different between the 2 groups. Five cases of bacteremia with vancomycin‐resistant enterococci (VRE) occurred in group B (vs none in group A), without related mortality. Two of these cases were preceded by positive VRE rectal surveillance cultures.CONCLUSIONSOutpatient intravenous antibiotic prophylaxis is feasible in children with acute myeloid leukemia and reduces the frequency of documented infection but not of febrile neutropenia. Despite the emergence of VRE bacteremia, the benefits favor antibiotic prophylaxis. Creative approaches to shorten the duration of prophylaxis and thereby minimize resistance should be explored. Cancer 2014;120:1985–1992. © 2014 American Cancer Society.
BAMS2 workspace: A comprehensive and versatile neuroinformatic platform for collating and processing neuroanatomical connections
Authors: Bota Mihail , Talpalaru Ştefan , Hintiryan Houri , Dong Hong‐Wei , Swanson Larry W. 
Published: March 2014

ABSTRACTWe describe a novel neuroinformatic platform, the BAMS2 Workspace (http://brancusi1.usc.edu), designed for storing and processing information on gray matter region axonal connections. This de novo constructed module allows registered users to collate their data directly by using a simple and versatile visual interface. It also allows construction and analysis of sets of connections associated with gray matter region nomenclatures from any designated species. The Workspace includes a set of tools allowing the display of data in matrix and networks formats and the uploading of processed information in visual, PDF, CSV, and Excel formats. Finally, the Workspace can be accessed anonymously by third‐party systems to create individualized connectivity networks. All features of the BAMS2 Workspace are described in detail and are demonstrated with connectivity reports collated in BAMS and associated with the rat sensory‐motor cortex, medial frontal cortex, and amygdalar regions. J. Comp. Neurol. 522:3160–3176, 2014. © 2014 Wiley Periodicals, Inc.
ZnGa2O4 Nanorod Arrays Decorated with Ag Nanoparticles as Surface‐Enhanced Raman‐Scattering Substrates for Melamine Detection
Authors: Chen Limiao , Jiang Dan , Liu Xiaohe , Qiu Guanzhou 
Published: March 2014

AbstractThe availability of sensitive, reproducible, and stable substrates is critically important for surface‐enhanced Raman spectroscopy (SERS)‐based applications, but it presently remains a challenge. In this work, well‐aligned zinc gallate (ZnGa2O4) nanorod arrays grown on a Si substrate by chemical vapor deposition were used as templates to fabricate SERS substrates by deposition of Ag nanoparticles onto the ZnGa2O4 nanorod surfaces. The coverage of the Ag nanoparticles on the ZnGa2O4 nanorod surfaces was easily controlled by varying the amount of AgNO3. SERS measurements showed that the number density of Ag nanoparticles on the ZnGa2O4 nanorod surfaces had a great effect on SERS activity. The SERS signals collected by point‐to‐point and SERS mapping images showed that as‐prepared SERS substrates exhibited good spatial uniformity and reproducibility. Detection of melamine molecules at low concentrations (1.0×10−7 M) was used as an example to show the possible application of such a substrate. In addition, the effect of benzoic acid on the detection of melamine was also investigated. It was found that the SERS signal intensity of melamine decreased greatly as the concentration of benzoic acid was increased.
Effect of Aluminum Doping on the Growth and Optical and Electrical Properties of ZnO Nanorods
Authors: Chen Ruiqiang , Zhu Pengli , Deng Libo , Zhao Tao , Sun Rong , Wong Chingping 
Published: March 2014

AbstractAluminum‐doped zinc oxide (AZO) nanorods were successfully prepared by a convenient solvothermal route. The crystal structure and morphology of AZO were characterized by XRD, SEM, and high‐resolution TEM. The length and diameter of AZO nanorods decreased with increasing Al content. The optical and electrical properties of AZO were studied by UV/Vis spectroscopy and a four‐point probe. The optical band gap of AZO increased initially because of the Burstein–Moss effect and then decreased as the Al content increased owing to the defects of AZO. The electrical resistivity of AZO nanorods varied conversely because of the change of electron and defect concentration (native and impurity defects). The native defect types, which were singly charged zinc and oxygen vacancies, were confirmed by photoluminescence spectroscopy. Moreover, not only the properties but also the growth mechanisms of AZO nanorods were affected by the defect concentrations of singly charged zinc vacancies and substituted Al, which were caused by increasing Al content. Finally, the AZO exhibited the smallest electrical resistivity with 1.5 at. % Al doping content, which was four orders of magnitude smaller than that of ZnO.
Functional traits composition predict macrophytes community productivity along a water depth gradient in a freshwater lake
Authors: Fu Hui , Zhong Jiayou , Yuan Guixiang , Ni Leyi , Xie Ping , Cao Te 
Published: March 2014

AbstractFunctional trait composition of plant communities has been proposed as a helpful key for understanding the mechanisms of biodiversity effects on ecosystem functioning. In this study, we applied a step‐wise modeling procedure to test the relative effects of taxonomic diversity, functional identity, and functional diversity on macrophytes community productivity along water depth gradient. We sampled 42 plots and 1513 individual plants and measured 16 functional traits and abundance of 17 macrophyte species. Results showed that there was a significant decrease in taxonomic diversity, functional identity (i.e., stem dry mass content, leaf [C] and leaf [N]), and functional diversity (i.e., floating leaf, mean Julian flowering date and rooting depth) with increasing water depth. For the multiple‐trait functional diversity (FD) indices, functional richness decreased, while functional divergence increased with water depth gradient. Macrophyte community productivity was strongly determined by functional trait composition within community, but not significantly affected by taxonomic diversity. Community‐weighted means (CWM) showed a two times higher explanatory power relative to FD indices in determining variations in community productivity. For nine of sixteen traits, CWM and FD showed significant correlations with community productivity, although the strength and direction of those relations depended on selected trait. Furthermore, functional composition in a community affected productivity through either additive or opposite effects of CWM and FD, depending on the particular traits being considered. Our results suggested both mechanisms of mass ratio and niche complementarity can operate simultaneously on variations in community productivity, and considering both CWM and FD would lead to a more profound understanding of traits–productivity relationships.