bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of wheat straw composite superabsorbent
Authors: Wan Tao , Huang Runqiu , Zhao Qihua , Xiong Lei , Qin Lili , Tan Xuemei , Cai Guojun 
Published: June 2013

ABSTRACTA novel wheat straw composite superabsorbent was prepared by graft polymerization with acrylic acid (AA), acrylamide (AM), and maleic anhydride‐modified wheat straw in aqueous solution, using N,N‐methylene‐bis‐acrylamide (MBA) as a cross‐linker and ammonium persulfate (APS) and sodium bisulfite (SBS) as redox initiators. Factors influencing the degree of carboxylation, such as reaction time, reaction temperature, and the amount of maleic anhydride, were investigated. Morphologies and structure of the wheat straw composite superabsorbent were characterized by fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), and X‐ray diffraction (XRD). Water absorption of wheat straw composite superabsorbent was rapid, requiring 13.1 min to reach 63% of equilibrium absorbency (781 g/g). FTIR spectra indicate that maleic anhydride has been reacted onto the wheat straw backbone and the structure of wheat straw graft copolymer is formed. SEM data show that the fibrous morphology of wheat straw disappears and gel aggregates with many large microporous holes are formed after wheat straw graft modification. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3404–3410, 2013
Biocomposite membranes of sodium alginate and silk fibroin fibers for biomedical applications
Authors: de Moraes Mariana Agostini , Beppu Marisa Masumi 
Published: June 2013

ABSTRACTBiocomposite membranes from biodegradable and biocompatible natural polymers were prepared from sodium alginate solution reinforced with silk fibroin fibers in several fiber content by casting and solvent evaporation. The properties of these biocomposites were investigated by scanning electron microscopy, swelling test, water vapor transmission, mechanical and thermal analyses, and cytotoxicity test. A biocomposite with uniform fiber dispersion and good fiber–matrix interaction was obtained through the incorporation of fibroin fibers in the alginate membrane, even though the fibers were used without any surface treatment to enhance the interfacial adhesion. The incorporation of fibroin fibers improved the tensile strength and also provided a new property to the alginate, that is, the resistance to tear. Moreover, the use of silk fibroin fibers in polymeric composites can result in a material with adequate characteristics for application in the biomaterial field, especially as wound dressings, because of its nontoxic effect to cells, flexibility, and resistance to tear. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3451–3457, 2013
Modeling of the atom transfer radical polymerization for preparing novel fluorosilicone diblock copolymers in a semi‐batch reactor
Authors: Huang Yao , Zhou Yin‐Ning , Zhang Qing , Luo Zheng‐Hong 
Published: June 2013

ABSTRACTTo investigate the process for the preparation of well‐defined poly‐dimethylsiloxane‐b−2,2,3,3,4,4,4‐heptafluorobutylmetharylate block copolymers via a macroinitiator initiated atom transfer radical polymerization (ATRP), a model for the batch and semi‐batch ATRP process was presented based on the method of moments. The ATRP mechanism, the diffusion limitation, and the reactor choice were considered in the model. Besides, the polymer molecular weight, monomer conversion, and polymer polydispersity index as a function of polymerization time were described by this model. The model was validated by comparing simulated results with experimental data and was also used to investigate the effects of diffusion limitation and reactor choice (i.e., batch and semi‐batch reactors). © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3473–3481, 2013
Stereoselective partitioning of organic substrates by thermoresponsive polymers in aqueous phases
Authors: Uemukai Toru , Torisaki Masashi , Hamanaka Takahiro , Ishifune Manabu 
Published: June 2013

ABSTRACTPartitioning of organic substrates by thermoresponsive polymer having N‐acryloylaminoalcohol moieties in aqueous phase has been studied. Thermoresponsive polymers, such as poly(N‐isopropylacrylamide) (PNIPAAm) and poly(NIPAAm‐co‐N‐acryloyl‐(±)‐alaninol) (poly(NIPAAm‐co‐HIPAAm)), were found to concentrate several organic substrates into the hydrophobic field generated during their phase transition. The amount of the substrates recoverd from the polymer phase mainly depended on the hydrophobicity of the substrates. Aqueous solutions of PNIPAAm (lower critical solution temperature, LCST = 33°C) and poly(NIPAAm‐co‐HIPAAm) (LSCT = 41°C) containing 1‐phenylethanol showed LCSTs at 22°C and 33°C, respectively. The changes of LCSTs indicate that specific interactions such as hydrogen bonding between the side chain functionalities of the polymers and the substrates influence the phase transition behavior. Moreover, new optically active polymers having chiral aminoalcohol moieties have been synthesized by copolymerizations of NIPAAm with N‐acryloylaminoalcohols such as N‐acryloyl‐(S)‐alaninol and N‐acryloyl‐(S)‐prolinol. The (R)/(S) ratio of 1‐phenylethanol recovered from poly(NIPAAm‐co‐N‐acryloyl‐(S)‐alaninol) and poly(NIPAAm‐co‐N‐acryloyl‐(S)‐prolinol) were determined to be 75/25 and 68/32, respectively. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3458–3464, 2013
Effect of aromatic additives with various alkyl groups on orientation birefringence of cellulose acetate propionate
Authors: Nobukawa Shogo , Aoki Yoshihiko , Yoshimura Hiroshi , Tachikawa Yutaka , Yamaguchi Masayuki 
Published: June 2013

ABSTRACTOrientation birefringence and its wavelength dispersion in blends of cellulose acetate propionate (CAP) and aromatic additive molecules having various alkyl chains were investigated, in order to evaluate the effect of the chemical structure on the optical properties. We found that the additive improved the orientation birefringence of CAP, meaning that the additive orientation is parallel to CAP chains via the “nematic interaction (NI)” reflecting the intermolecular orientation correlation. The NI strength was evaluated by using a theory concerning the molecular orientation. The result demonstrates that the alkyl chain length in the additive molecule strongly affects the orientation correlation. Although the intrinsic birefringence monotonically decreases with the alkyl chain length, the NI strength shows the highest value between the additive with propionyl group and CAP. From the result, the contribution of birefringence from the aromatic molecule, which is determined by the intrinsic birefringence and orientation function, needs to be considered to design the optical films with high performances. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3465–3472, 2013
Structure, properties, and mechanism of reactive compatibilization of epoxy to polyphenylene sulfide/polyamide elastomer
Authors: Gui Hao , Zhou Tao , Li Lin , Zhou Ting , Liu Feiwei , Zhan Yanhui , Zhang Aimin 
Published: June 2013

ABSTRACTIn this article, the structure, properties, and mechanism of reactive compatibilization of epoxy (EP) to polyphenylene sulfide (PPS)/polyamide elastomer (PAe) were investigated in detail. A PPS/PAe/EP ternary system was successfully prepared via reactive extrusion. Its mechanical and rheological properties were greatly improved compared with those of conventional PPS/PAe binary system. The addition of EP to PPS/PAe blend induced a series of chemical reactions. The chain‐extended reaction of PPS was verified by high pressure capillary rheometer. The grafting reaction of PPS with PAe was testified by FTIR. The curing reaction of EP was proposed to explain the decreasing of the mechanical properties in PPS/PAe/EP ternary blend when it contained a high content of EP. Additionally, a toughened model was also proposed in PPS/PAe/EP ternary system. The improvement of toughness was attributed to the activation of matrix molecules in the shear band region. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3411–3420, 2013
The Dynamics of Lysozyme from Bacteriophage Lambda in Solution Probed by NMR and MD Simulations
Authors: Smith Lorna J. , Bowen Alice M. , Di Paolo Alexandre , Matagne André , Redfield Christina 
Published: June 2013

Abstract15N NMR relaxation studies, analyses of NMR data to include chemical shifts, residual dipolar couplings (RDC), NOEs and HN–Hα coupling constants, and molecular dynamics (MD) simulations have been used to characterise the behaviour of lysozyme from bacteriophage lambda (λ lysozyme) in solution. The lower and upper lip regions in λ lysozyme (residues 51–60 and 128–141, respectively) show reduced 1H–15N order parameters indicating mobility on a picosecond timescale. In addition, residues in the lower and upper lips also show exchange contributions to T2 indicative of slower timescale motions. The chemical shift, RDC, coupling constant and NOE data for λ lysozyme indicate that two fluctuating β‐strands (β3 and β4) are populated in the lower lip region while the N terminus of helix α6 (residues 136–139) forms dynamic helical turns in the upper lip region. This behaviour is confirmed by MD simulations that show hydrogen bonds, indicative of the β‐sheet and helical secondary structure in the lip regions, with populations of 40–60 %. Thus in solution λ lysozyme adopts a conformational ensemble that will contain both the open and closed forms observed in the crystal structures of the protein.
Quellungsexperimente mit Superabsorber‐Polymeren
Authors: Granz Jessica , Maulbetsch Christoph 
Published: June 2013

AbstractDie Quellungskinetik von Superabsorbern‐Polymeren (SAP) kann auf verschiedene Weise gemessen werden. Wir haben drei in der Literatur beschriebene Methoden auf ihre Verwendbarkeit im Chemieunterricht getestet. Die verschiedenen Methoden ergeben alle vergleichbare Sättigungsfunktionen für die Quellung und können zur Charakterisierung von SAP oder als einfache Beispiele in der Kinetik eingesetzt werden.Swelling kinetics of superabsorbent polymers (SAP) can be measured by different experimental techniques. Three of these methods (filter, tea bag weight method and VIS spectrometry) were checked for their usefulness as experiments in chemistry classes. All experiments reproducibly yielded a saturation function for the swelling kinetics and can either be used to characterize SAP or to demonstrate simple kinetics.
Higher homocysteine and lower betaine increase the risk of microangiopathy in patients with diabetes mellitus carrying the GG genotype of PEMT G774C
Authors: Chen Li , Chen Yan‐ming , Wang Li‐jun , Wei Jun , Tan Yao‐zong , Zhou Jing‐ya , Yang Yang , Chen Yu‐ming , Ling Wen‐hua , Zhu Hui‐lian 
Published: June 2013

AbstractBackgroundDiabetes represents one of the greatest medical and socioeconomic threats worldwide. The pathogenesis involved is complicated. The effect of methyl donors and genetic polymorphisms in metabolic enzymes on the risk of microangiopathy in patients with diabetes is not well understood. This study investigates the association of homocysteine, choline and betaine levels and phosphatidylethanolamine N‐methyltransferase (PEMT) G774C (rs12325817) genotypes with the risk of diabetes and its related microangiopathic complications.MethodsBetween January 2009 and June 2010, 184 diabetic patients and 188 non‐diabetic control subjects were enrolled in the hospital‐based case‐control study. Serum concentrations of betaine and choline were determined by high‐performance liquid chromatography (HPLC)–mass spectrometry. Serum concentrations of homocysteine were assayed using HPLC. PEMT gene mutations were detected by polymerase chain reaction and restriction fragment length polymorphism.ResultsAfter adjustment for potential confounders, serum total homocysteine had a significant dose‐dependent positive association, and serum choline had an inverse association with the risks of diabetes and its microangiopathic complications (both p < 0.001). Although serum betaine was not associated with the risk of diabetes, it had a significant inverse association with diabetic microangiopathy. Compared with GG genotype, the CC genotype of PEMT G774C was associated with a decreased risk of diabetes (OR 0.559, 95% CI 0.338, 0.926) and its microangiopathy (OR 0.452, 95% CI 0.218, 0.937).ConclusionThe GG genotype of the PEMT G774C polymorphism, higher levels of serum homocysteine and lower levels of serum betaine are associated with an increased risk of microangiopathy in patients with diabetes. Copyright © 2013 John Wiley & Sons, Ltd.
The First Combined Experimental and Theoretical Evaluation of Tetravalent Cation Conduction in a Solid
Authors: Nunotani Naoyoshi , Tamura Shinji , Imanaka Nobuhito 
Published: June 2013

AbstractTetravalent tellurium ion conduction in solids has been demonstrated in α‐Te2MoO7 by both experimental and theoretical means for the first time. Although it has been commonly considered that the Te4+ ion will not conduct appreciably in solids due to its high valency, such conduction can be successfully achieved in solid α‐Te2MoO7, which has a 2D layered structure conducive to ion migration. The measured Te4+ ion conductivity in solid α‐Te2MoO7 (1.0 × 10–2 S cm–1 at 530 °C) reaches the threshold required for practical applications. Evidence for Te4+ ion conduction in α‐Te2MoO7 is provided both directly by DC electrolysis results and theoretically by MEM analysis.
A Family of Homologous Heterospin Complexes Based on Lanthanides and Biradical Ligands
Authors: Tian Li , Sun Ya‐Qiu , Na Bo , Cheng Peng 
Published: June 2013

AbstractFour complexes based on rare earth biradicals [Ln(hfac)3(NITPhmbis)2]2 {Ln = La (1), Nd (2), Gd (3), Tb (4); hfac = hexafluoroacetylacetone; NITPhmbis = [1,3‐bis(1′‐oxyl‐3′‐oxido‐4′,4′,5′,5′‐tetramethyl‐4,5‐hydro‐1H‐imidazol‐2‐yl)benzene]} were successfully synthesized under appropriate conditions. Single‐crystal structures show that 1 is a mononuclear two spin complex and 2–4 are mononuclear three spin complexes, in which a NITPhmbis molecule acts as a bidentate ligand with one coordinated lanthanide ion. The four complexes are isomorphous, the coordination number around the lanthanide ion is eight, and the polyhedron is a 4,4‐bicappped trigonal prism. For lanthanum(III) complex 1, the temperature dependence of the magnetic susceptibility indicates that weakly antiferromagnetically coupled radicals exist (Jrad–rad = –1.2 cm–1). In the case of neodymium(III) complex 2, its magnetic behavior gives antiferromagnetic NdIII–radical interactions, whereas for complexes 3 and 4, static magnetic properties show that the GdIII and TbIII ions interact ferromagnetically with the radical. The dynamic magnetic properties of 4 were also measured, and 4 was found to exhibit slow relaxation of the magnetization at low temperature.
Forecasting Call Centre Arrivals
Authors: Millán‒Ruiz David , Hidalgo J. Ignacio 
Published: June 2013

ABSTRACTThis article presents a novel neural network‒based approach to the intra‒day forecasting of call arrivals in call centres. We apply the method to individual time series of arrivals for different customer call groups. To train the model, we use historical call data from three months and, for each day, we aggregate the call volume in 288 intervals of 5 minutes. With these data, our method can be used for predicting the call volume in the next 5‒minute interval using either previous real data or previous predictions to iteratively produce multi‒step‒ahead forecasts. We compare our approach with other conventional forecasting techniques. Experimental results provide factual evidence in favour of our approach. Copyright © 2013 John Wiley & Sons, Ltd.
Exploring hydroclimatic change disparity via the Budyko framework
Authors: van der Velde Ype , Vercauteren Nikki , Jaramillo Fernando , Dekker Stefan C. , Destouni Georgia , Lyon Steve W. 
Published: June 2013

AbstractThe Budyko framework characterizes landscape water cycles as a function of climate. We used this framework to identify regions with contrasting hydroclimatic change during the past 50 years in Sweden. This analysis revealed three distinct regions: the mountains, the forests, and the areas with agriculture. Each region responded markedly different to recent climate and anthropogenic changes, and within each region, we identified the most sensitive subregions. These results highlight the need for regional differentiation in climate change adaptation strategies to protect vulnerable ecosystems and freshwater resources. Further, the Budyko curve moved systematically towards its water and energy limits, indicating augmentation of the water cycle driven by changing vegetation, climate and human interactions. This finding challenges the steady state assumption of the Budyko curve and therefore its ability to predict future water cycles. Copyright © 2013 John Wiley & Sons, Ltd.
Influence of pig manure biochar mineral content on Cr(III) sorption capacity
Authors: Wnetrzak Renata , Leahy J.J. , Chojnacka Katarzyna W. , Saeid Agnieszka , Novotny Etelvino , Jensen Lars Stoumann , Kwapinski Witold 
Published: June 2013

AbstractBACKGROUNDThe adsorption of Cr(III) ions on various pig manure biochar (BC) samples was investigated to determine the effect of operating conditions (initial pH, sorbate and sorbent concentrations) on sorptive capacity. The BC samples with higher sorption capacity showed high surface area and were rich in alkaline metals whose concentration was measured by ICP‐OES.RESULTSFor BCs from anaerobically and chemically pretreated feedstock greater ΔpH changes and higher maximum capacity were noted during Cr(III) adsorption than for BC from mechanically pretreated samples, due to a higher ion exchange capacity. The maximum Cr(III) uptake of 102 mg g‐1 for the BC sample was achieved at c0 = 300 mg dm‐3 and pH = 5. It was also observed that the high ash content effectively lowered the surface area of BCs; however all BCs investigated contained a low level of toxic metals.CONCLUSIONSThe data indicate that both the technology used for separation of the manure and pyrolysis temperature had a significant influence on the physical and chemical properties of the BC and affected its sorption capacity. In addition, compared with other sorbents pig manure BC has one of the best Cr(III) sorption capacities. © 2013 Society of Chemical Industry
Multidimensional GC using planar microfluidic devices for the characterization of phenolic antioxidants in fuels
Authors: Luong Jim , Gras Ronda , Cortes Hernan J. , Shellie Robert A. 
Published: June 2013

A multidimensional gas chromatographic approach using planar microfluidic devices for Deans switching has been developed and implemented for the characterization of sterically hindered phenolic compounds used as antioxidants in fuels. Detection and quantitation was conducted with MS in selected ion monitoring mode. A complete analysis is conducted in less than 15 min with precision greater than 5.5% at 1 and 25 ppm w/w (ppmw). LODs of 50 ppb w/w (ppbw) or better in selected ion monitoring mode and a linear range of 100 ppbw to 100 ppmw with a correlation coefficient greater than 0.998 were attained for all analytes. Unique to this analytical configuration is the use of a mass spectrometer capable of monitoring the column effluent from either dimension by incorporating a high‐temperature rotary valve and a three‐port planar microfluidic device. High‐molecular‐weight (C25–C40) fuel contaminants eluting from the first column can be selectively sent to the mass spectrometer for profile characterization in scan mode. These compounds would otherwise be retained substantially by the low‐phase‐ratio analytical column employed in the second dimension.
Inequality‐based reliability estimates for complex systems
Authors: Hill Stacy D. , Spall James C. , Maranzano Coire J. 
Published: June 2013

AbstractFull‐system testing for large‐scale systems is often infeasible or very costly. Thus, when estimating system reliability, it is desirable to use a method that uses subsystem tests, which are often less expensive and more feasible. This article presents a method for bounding full‐system reliabilities based on subsystem tests and, if available, full‐system tests. The method does not require that subsystems be independent. It accounts for dependencies through the use of certain probability inequalities. The inequalities provide the basis for valid reliability calculations while not requiring independent subsystems or full‐system tests. The inequalities allow for test information on pairwise subsystem failure modes to be incorporated, thereby improving the bound on system reliability. We illustrate some of the properties of the estimates via an example application. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013
Rural Rickets: Vitamin D Deficiency in a Post‐Medieval Farming Community from the Netherlands
Authors: Veselka Barbara , Hoogland Menno L.P. , Waters‐Rist Andrea L. 
Published: June 2013

AbstractRickets is caused by vitamin D deficiency as a result of limited exposure to sunlight and inadequate diet. In the 19thcentury, rickets was endemic in most northern European cities. In post‐Medieval Netherlands, rickets is documented in low frequencies in a few urban samples, but has not been studied in contemporaneous rural populations. Beemster is a rural farming community in the Netherlands that was established in the 17thcentury upon drained land, with the Middenbeemster cemetery in use until 1866 AD. Ninety‐five individuals from the ages of 32 weeksin uteroto 15 years were examined for rickets in order to understand factors that can cause vitamin D deficiency in rural, non‐industrialized populations. To identify rickets in the Beemster sample, ten features were scored, with bending deformities of the lower limb and one other feature, or at least three non‐bending features, having to be present in order for diagnosis. Nine individuals (9.5%) had evidence of rickets—a high prevalence, especially for a rural community where ample sunlight was available. The two and three year old Beemster infants were most heavily affected with an age‐specific prevalence of 30.4%. Two three‐month‐old infants also had rickets. Some of the affected may have developed rickets secondarily, as a result of a different illness, but cultural practices including prolonged swaddling, occlusive clothing, and keeping the young indoors, are suggested to have contributed to this high rickets prevalence. Dietary variables including poor weaning foods and common episodes of malnutrition may have also contributed to vitamin D deficiency. This study demonstrates the value of careful analysis of pathological conditions in subadults and highlights that rickets was not only a disease of cities, but affected populations that would appear to have been at low risk, because of maladaptive cultural practices. Copyright © 2013 John Wiley & Sons, Ltd.
Optimal control of perpetual CPDO: minimal cash‐out probability and maximal conditional return
Authors: Yang Xiaoli , Liang Jin , Wu Yuan 
Published: June 2013

SUMMARYIn this paper, the optimal leverage function for a perpetual Constant Proportion Debt Obligation (CPDOs) is derived by solving a highly nonlinear Hamilton–Jacobi–Bellman equation with initial conditions. The model to minimize the default probability was built, then the optimal payoff under the condition of minimal default probability is also worked out. The stochastic optimal control theory is utilized to determine the optimal leverage function for the minimization of default probability. Then, the optimal upper bound of the leverage is chosen to obtain a perfect return of the investor. All the equations derived from the above problems have explicit solutions. Based on the solutions, numerical examples are provided, and the relationships between the optimal leverage, as well as the optimal upper bound, and the parameters in the problem, are shown in the figures. Copyright © 2013 John Wiley & Sons, Ltd.