bluuebunny/crossref_metadata_2025_split huggingface dataset:
Performances of larch (larix gmelini) tannin modified urea–formaldehyde (TUF) resin and plywood bonded by TUF resin
Authors: Zhang Jizhi , Kang Haijiao , Gao Qiang , Li Jianzhang , Pizzi Antonio , Delmotte Luc 
Published: June 2014

ABSTRACTTannin from larch (Larix gmelini) bark extracts, as a natural renewable resource, was used to prepare tannin–urea–formaldehyde (TUF) resin. The chemical structures of larch tannin and TUF resin were characterized by matrix‐assisted laser desorption/ionization‐time of flight mass spectrometry and 13C nuclear magnetic resonance. The thermal behaviors of TUF resin were evaluated by differential scanning calorimetry (DSC) and thermomechanical analysis (TMA). The performances of TUF resin were investigated by measuring the bond strength and formaldehyde emission of its bonded plywood. It was clearly shown that larch tannin is mainly composed of prodelphinidin repeating units. Phenolic groups were introduced into TUF resin mainly linked by methylene bond. Larch tannin has an adverse effect on the resin curing. However, it promoted the rigidity and flexibility of the glued system and upgraded the properties of plywood. Therefore, larch tannin could be applied in the modification of urea–formaldehyde resin. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41064.
Effect of solvents on morphology and polymorphism of polyvinylidene fluoride membrane via supercritical CO2 induced phase separation
Authors: Xiang Yanhui , Xue Lixin , Shen Jianhui , Lin Haibo , Liu Fu 
Published: June 2014

ABSTRACTPoly vinylidene fluoride (PVDF) membranes were prepared via supercritical CO2 induced phase separation. The effects of solvent power on PVDF membrane morphology and polymorphism were investigated using N‐N‐dimethylformamide (DMF), triethyl phosphate (TEP), and their mixture respectively. The morphology evolution including cross‐section and surfaces were thoroughly studied by scanning electron microscope (SEM) and atomic force microscopy (AFM). The differences of solubility parameters between the solvent and PVDF affected the phase separation and the resultant morphology. The various crystalline phases of the membranes were mainly investigated by Fourier transform infrared spectroscopy (FTIR) and X‐ray diffractometer (XRD). Solvent with larger dipole moment tended to form polar β phase. Decreasing the difference of solubility parameters favored the formation of α phase. Furthermore, the effects of salt additive on PVDF membrane morphology and crystalline form were studied as well. Results turned out that lithium chloride (LiCl) induced a porous top surface and boosted the formation of β phase. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41065.
Effects of quasi‐3D stacking architecture on interlaminar shear strength and void content of FRP
Authors: Zhang Xiaohui , Duan Yugang , Zhao Xinming , Li Dichen 
Published: June 2014

ABSTRACTTo improve the interlaminar shear strength (ILSS) of composite laminate, three different quasi‐3D stacking architecture (q‐3DSA) laminates were fabricated by using automated fiber placement process and a traditional 2D stacking architecture (2DSA) laminate was fabricated as the control sample. The distribution of voids, the density, and the ILSS of four types of laminates were tested. The results indicated that the void content of the different q‐3DSA laminates was approximately 0.71%–3.07% greater than that of the 2DSA laminate, but the ILSS of q‐3DSA laminates was 5.49%–12.54% better than that of the 2DSA laminate. The microstructure images showed that the cracks spread along the interface between the adjacent layers in the 2DSA laminate, while the cracks cross two or more layers in the q‐3DSA laminates. This behavior indicated that the q‐3DSA improved the ILSS by dispersing the interlaminar load through the bended and interlaced tows in the laminate. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41076.
Synthesis and characterization of crosslinked chitosan immobilized on bentonite and its grafted products with polyaniline
Authors: El‐Dib Fawzia I. , Hussein Mohammed H. M. , Hefni Hassan H. H. , Eshaq Ghada , ElMetwally Ahmed E. 
Published: June 2014

ABSTRACTChitosan immobilized bentonite (CIB) namely chitosan‐coated bentonite (5% chitosan content) was synthesized in 2% acetic acid solution, followed by crosslinking, using epichlorohydrien (ECH). The so‐obtained crosslinked chitosan immobilized on bentonite (CIB‐ECH) and CIB composites were grafted with polyaniline (PANI) through oxidative‐radical copolymerization using ammonium peroxydisulfate in acidic medium to produce PANI‐grafted crosslinked chitosan immobilized on bentonite (PANI‐g‐CIB‐ECH) and PANI‐grafted‐chitosan immobilized on bentonite (PANI‐g‐CIB) composites, respectively. The resultant composites were characterized by using X‐ray diffraction (XRD), thermo gravimetric analysis/differential scanning calorimetry, scanning electron microscopy, Fourier transform infrared (FTIR), and electrical conductivity. XRD and FTIR analyses indicate that chitosan was not intercalated into the silicate layer. Also the electrical conductivity elucidates that the grafted composites fall in the range required for the application as electrostatic dissipation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41078.
Regimes of microstructural evolution as observed from rheology and surface morphology of crosslinked poly(vinyl alcohol) and hyaluronic acid blends during gelation
Authors: Kodavaty Jagadeeshwar , Deshpande Abhijit P 
Published: June 2014

ABSTRACTHyaluronic acid (HA)‐based materials are being investigated because of their role in biological fluids and tissues. Poly(vinyl alcohol) (PVA) when blended with HA at different compositions leads to superior mechanical properties compared to pure HA. The PVAHA blend hydrogels are potential candidates for pharmaceutical, biomedical, and cosmetic applications. It is essential to understand the structure, gelation time, and morphological properties of these hydrogels. In this work, a blend system of PVA crosslinked with glutaraldehyde in the presence of HA is studied. Semidilute solutions of PVA and HA are blended, followed by gelation due to crosslinking. The crosslinked gels as well as the gel cast membranes were examined. The effect of HA on the gelation process is investigated using rheological characterization. It is shown that kinetics of gelation is influenced by HA content, though storage modulus of the gels is influenced marginally. The structural features of PVAHA gels were also probed with scanning electron microscopy and dynamic light scattering. It is argued that there is a complex interplay between intra‐ and intermolecular crosslinking of PVA and PVA–HA interactions during the gel formation. Based on the insights obtained from various probing techniques for PVAHA gels with different HA content, three broad structural features were identified. It is shown that the hydrogel is semi‐interpenetrating network at lower HA content (<10% HA), cocontinuous morphology at moderate HA content and with domains at high HA content (>20% HA). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41081.
pH responsive polymers with amino acids in the side chains and their potential applications
Authors: Roy Saswati Ghosh , De Priyadarsi 
Published: June 2014

ABSTRACTDesign and synthesis of pH responsive polymeric materials has become an important subject in academia as well as in industrial field in recent years due to their applications in diverse field including controlled drug delivery, biomedical applications, membrane science, sensors and actuators, oil recovery, colloid stabilization, etc. Efforts have been made to incorporate stimuli‐responsive biomolecules in synthetic polymers to develop pH responsive “smart” non‐biological hybrid macromolecules with high water solubility, enhanced biocompatibility, bio‐mimetic structure and properties. This review is focused on the recent advances in side‐chain amino acid‐based pH responsive polymers synthesis and potential application aspects of these macromolecular architectures in drug and gene delivery, and other fields. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41084.
Flame retardance and origin of bismaleimide resin composites with green and efficient aluminum phosphates
Authors: You Qiuqin , Yuan Li , Wang Hong , Liang Guozheng , Gu Aijuan 
Published: June 2014

ABSTRACTDeveloping green and high efficiency inorganic flame retardants is the trend of preparing flame retarding polymer composites. Aluminum phosphates (t‐hAP) with uniform, small dimension, and hexagonal structure were facilely synthesized, which have similar size (1–2 μm) but different structures from commercial spherical‐like aluminum phosphate (cAP). The flame retardance of bismaleimide (BD)/t‐hAP and BD/cAP composites were intensively investigated. t‐hAP is proved to have much better flame retarding effect than cAP, but also exhibits advantages over Mg(OH)2 and Al(OH)3. With only 5 wt % addition of t‐hAP into BD resin, the peak and total heat releases as well as total smoke production significantly reduce 42.3, 47.8, and 67.3%, respectively; besides, better data are obtained as the loading of t‐hAP increases to 10 wt %. These attractive data result from three effects induced by t‐hAP. Besides the better protection role of sheet structure, the strong hydrogen bonding between t‐hAP and BD resin endows the composite with good dispersion of t‐hAP and high crosslinking density; moreover, t‐hAP releases H2O and NH3, diluting flammable gases during combustion. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41089.
Effect of lignin removal on mechanical, thermal, and morphological properties of polylactide/starch/rice husk blend used in food packaging
Authors: Mohammadi‐Rovshandeh Jamshid , Pouresmaeel‐Selakjani Peyman , Davachi Seyed Mohammad , Kaffashi Babak , Hassani Atieh , Bahmeyi Alireza 
Published: June 2014

ABSTRACTThe aim of this work was to investigate the possibility of using cost‐effective natural filler in a biodegradable polymer and find new set of materials for green biocomposites to be used in food packaging. In this regard, rice husk (RH) and bleached rice husk (BRH) have been used in the form of powder and the effect of lignin removal on mechanical and thermal properties of prepared composites with poly(l‐lactide) and starch were studied. Using FTIR technique, the lignin removal from RH has been approved. The tensile, charpy impact, and hardness tests were implemented to investigate the mechanical properties. It was concluded that filler caused increase both in the toughness and the Young modulus of samples. It was also found that the lack of lignin in BRH samples improves the mechanical properties. It was clearly observed that the BRH samples show larger modulus, charpy impact strength, and hardness compared to those filled with RH. Despite larger values for the elongations at break of RH samples, the mechanical properties showed a significant improvement (between 25 and 50% improvements) on lignin removal. The differential scanning calorimetry thermograms revealed an improvement in crystallization behavior and reduction of Tg from 47 to 31°C in the case of BRH‐filled samples. Finally, due to the removal of toxic lignin in the samples and modification of mechanical properties by this method, the BRH could have the ability of wide use in the bioplastics and food packaging industries. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41095.
Selective Tumor Necrosis Factor Receptor I Blockade Is Antiinflammatory and Reveals Immunoregulatory Role of Tumor Necrosis Factor Receptor II in Collagen‐Induced Arthritis
Authors: McCann Fiona E. , Perocheau Dany P. , Ruspi Gerhard , Blazek Katrina , Davies Marie L. , Feldmann Marc , Dean Jonathan L. E. , Stoop A. Allart , Williams Richard O. 
Published: June 2014

ObjectiveTumor necrosis factor (TNF) signals via 2 receptors, TNFR type I (TNFRI) and TNFRII, with distinct cellular distribution and signaling functions. In rheumatoid arthritis (RA), the net effect of TNFR signaling favors inflammatory responses while inhibiting the activity of regulatory T cells. TNFRII signaling has been shown to promote Treg cell function. To assess the relative contributions of TNFRI and TNFRII signaling to inflammatory and regulatory responses in vivo, we compared the effect of TNF blockade, hence TNFRI/II, versus TNFRI alone in collagen‐induced arthritis (CIA) as a model of RA.MethodsMice with established arthritis were treated for 10 days with anti‐mouse TNFRI domain antibody (dAb; DMS5540), an isotype control dAb (DMS5538), or murine TNFRII genetically fused with mouse IgG1 Fc domain (mTNFRII‐Fc) beginning on the day of arthritis onset, and disease progression was monitored. Systemic cytokine concentrations and numbers of T cell subsets in lymph nodes and spleens were measured, and intrinsic Treg cell function was determined by ex vivo suppression assays.ResultsProgression of CIA was suppressed similarly by TNFRI (DMS5540) and TNFRI/II (mTNFRII‐Fc) blockade. However, blockade of TNFRI/II led to increased effector T cell activity, which was not observed after selective TNFRI blockade, suggesting an immunoregulatory role of TNFRII. In support of this, TNFRI blockade, but not TNFRI/II blockade, expanded and activated Treg cells. Furthermore, a dramatic increase in expression of the Treg cell signature genes FoxP3 and TNFRII was observed in joints undergoing remission, which supports the notion that these molecules have a physiologic role in the resolution of inflammation.ConclusionWe propose that a therapeutic strategy that targets TNFRI while sparing TNFRII has the potential to both inhibit inflammation and promote Treg cell activity, which might be superior to TNF blockade.
Magnetic Coupling Constants of Self‐Assembled CuII [3×3] Grids: Alternative Spin Model from Theoretical Calculations
Authors: Calzado Carmen J. , Ben Amor Nadia , Maynau Daniel 
Published: June 2014

AbstractThis paper reports a theoretical analysis of the electronic structure and magnetic properties of a ferromagnetic CuII [3×3] grid. A two‐step strategy, combining calculations on the whole grid and on binuclear fragments, has been employed to evaluate all the magnetic interactions in the grid. The calculations confirm an S=7/2 ground state, which is in accordance with the magnetisation versus field curve and the thermal dependence of the magnetic moment data. Only the first‐neighbour coupling terms present non‐negligible amplitudes, all of them in agreement with the structure and arrangement of the Cu 3d magnetic orbitals. The results indicate that the dominant interaction in the system is the antiferromagnetic coupling between the ring and the central Cu sites (J3=J4≈−31 cm−1). In the ring two different interactions can be distinguished, J1=4.6 cm−1 and J2=−0.1 cm−1, in contrast to the single J model employed in the magnetic data fit. The calculated J values have been used to determine the energy level distribution of the Heisenberg magnetic states. The effective magnetic moment versus temperature plot resulting from this ab initio energy profile is in good agreement with the experimental curve and the fitting obtained with the simplified spin model, despite the differences between these two spin models. This study underlines the role that the theoretical evaluations of the coupling constants can play on the rationalisation of the magnetic properties of these complex polynuclear systems.
Antiaromaticity to Aromaticity: From Boroles to 1,2‐Azaborinines by Ring Expansion with Azides
Authors: Braunschweig Holger , Hörl Christian , Mailänder Lisa , Radacki Krzysztof , Wahler Johannes 
Published: June 2014

AbstractWe have exploited the reactivity of antiaromatic boroles, gaining access to aryl‐substituted monocyclic 1,2‐azaborinines. The observed ring‐expansion reaction of inherently electron‐deficient boroles with organometallic and organic azides is demonstrated for representative examples. This substance class is expected to provide a new avenue into 1,2‐azaborinine chemistry, especially in the area of functional organoboron materials. Our results are based on NMR and UV/Vis spectroscopy as well as single‐crystal X‐ray crystallography and provide a virtually quantitative approach that also offers numerous points of variation.
Nickel‐Catalyzed Site‐Selective Amidation of Unactivated C(sp3)H Bonds
Authors: Wu Xuesong , Zhao Yan , Ge Haibo 
Published: June 2014

AbstractIntramolecular dehydrogenative cyclization of aliphatic amides was achieved on unactivated sp3 carbon atoms by a nickel‐catalyzed CH bond functionalization process with the assistance of a bidentate directing group. The reaction favors the CH bonds of β‐methyl groups over the γ‐methyl or β‐methylene groups. Additionally, a predominant preference for the β‐methyl CH bonds over the aromatic sp2 CH bonds was observed. Moreover, this process also allows for the effective functionalization of benzylic secondary sp3 CH bonds.
Review of Mixed‐Integer Nonlinear and Generalized Disjunctive Programming Methods
Authors: Trespalacios Francisco , Grossmann Ignacio E. 
Published: June 2014

AbstractThis work presents a review of the main deterministic mixed‐integer nonlinear programming (MINLP) solution methods for problems with convex and nonconvex functions. An overview for deriving MINLP formulations through generalized disjunctive programming (GDP), which is an alternative higher‐level representation of MINLP problems, is also presented. A review of solution methods for GDP problems is provided. Some relevant applications of MINLP and GDP in process systems engineering are described in this work.
Study on the Spatial Variation of the Geoelectric Field Signals Recorded at the Stations in the Eastern Huabei Area in China When a Heavy Current is Injected
Authors: Qin‐Zhong MA , Wi LI , Ji‐Hong ZHANG , Yu‐Gui GUO , Guo‐Qing FANG 
Published: June 2014

AbstractIn the study of seismo‐electromagnetics, the relation between the flowing characteristics of electric current and the geological structure is a very important problem. The distribution of many geoelectric field stations and heavy current inflow into the underground offer us a golden opportunity to study the scientific problem. In this paper, by studying the signals originated from grounding electrode 2100∼3004 A current of Qingdao converter station and recorded at twenty one geoelectric field stations in the east Huabei area in China, we could have a better understanding of the variation of the geoelectric field. The study shows that (1) the telluric current signals present extremely big variation along the directions of the Tan‐Lu fault and the southwest beyond the fault zone as well as the northwest of it, where current signal could be recorded, and there are obvious directionality feature and the phenomenon of sensitive site; (2) the larger the current intensity of the source is, the higher the signal strength recorded at observatory stations is. When the current intensity of the source changed from 2100 A to 3004 A the increase rate of the signals recorded on the long electrode is different from that on short electrode at many stations; (3) the uniformity degree of the geoelectric field in the area does not follow the regular patterns of homogeneous medium, which illustrates that the characteristics of inhomogeneous medium and anisotropy are obvious at many stations in the area; (4) there are few stations that could be used to determine the direction of the source, but the azimuth obtained at Anqiu, Dashan and Xinyi stations could be used to locate the source site when a large current was injected. Considering the influence of the three factors, i.e., the device system consisting of a point source and the electrode distribution of a station, the heterogeneity of medium in a large area, as well as the fine structure of the medium underground at a station, this paper has made a deep analysis and explanation of the characteristics mentioned above by numerical simulation.
Distribution and innervation of putative arterial chemoreceptors in the bullfrog (Rana catesbeiana)
Authors: Reyes Catalina , Fong Angelina Y. , Brink Dee L. , Milsom William K. 
Published: June 2014

ABSTRACTPeripheral arterial chemoreceptors have been located previously in the carotid labyrinth, the aortic arch, and the pulmocutaneous artery of frogs. In the present study we used cholera toxin B neuronal tract tracing and immunohistochemical markers for cholinergic cells (vesicular acetylcholine transporter [VAChT]), tyrosine hydroxylase (TH), and serotonin (5HT) to identify putative O2‐sensing cells in Rana catesbeiana. We found potential O2‐sensing cells in all three vascular areas innervated by branches of the vagus nerve, whereas only cells in the carotid labyrinth were innervated by the glossopharyngeal nerve. Cells containing either 5HT or TH were found in all three sites, whereas cells containing both neurotransmitters were found only in the carotid labyrinth. Cell bodies containing VAChT were not found at any site. The morphology and innervation of putative O2‐sensing cells were similar to those of glomus cells found in other vertebrates. The presence of 5HT‐ and TH‐immunoreactive cells in the aorta, pulmocutaneous artery, and carotid labyrinth appears to reflect a phylogenetic transition between the major neurotransmitter seen in the putative O2‐sensing cells of fish (5HT) and those found in the glomus cells of mammals (acetylcholine, adenosine, and catecholamines). J. Comp. Neurol. 522:3754–3774, 2014. © 2014 Wiley Periodicals, Inc.
Long‐term decrease in satellite vegetation indices in response to environmental variables in an iconic desert riparian ecosystem: the Upper San Pedro, Arizona, United States
Authors: Nguyen Uyen , Glenn Edward P. , Nagler Pamela L. , Scott Russell L. 
Published: June 2014

AbstractThe Upper San Pedro River is one of the few remaining undammed rivers that maintain a vibrant riparian ecosystem in the southwest United States. However, its riparian forest is threatened by diminishing groundwater and surface water inputs, due to either changes in watershed characteristics such as changes in riparian and upland vegetation, or human activities such as regional groundwater pumping. We used satellite vegetation indices to quantify the green leaf density of the groundwater‐dependent riparian forest from 1984 to 2012. The river was divided into a southern, upstream (mainly perennial flow) reach and a northern, downstream (mainly intermittent and ephemeral flow) reach. Pre‐monsoon (June) Landsat normalized difference vegetation index (NDVI) values showed a 20% drop for the northern reach (P < 0·001) and no net change for the southern reach (P > 0·05). NDVI and enhanced vegetation index values were positively correlated (P < 0·05) with river flows, which decreased over the study period in the northern reach, and negatively correlated (P < 0·05) with air temperatures in both reaches, which have increased by 1·4 °C from 1932 to 2012. NDVI in the uplands around the river did not increase from 1984 to 2012, suggesting that increased evapotranspiration in the uplands was not a factor in reducing river flows. Climate change, regional groundwater pumping, changes in the intensity of monsoon rain events and lack of overbank flooding are feasible explanations for deterioration of the riparian forest in the northern reach. Copyright © 2014 John Wiley & Sons, Ltd.