bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of nucleating agents on the morphologies and performances of poly(vinylidene fluoride) microporous membranes via thermally induced phase separation
Authors: Liu Min , Chen Dong‐Gen , Xu Zhen‐Liang , Wei Yong‐Ming , Tong Meng 
Published: July 2012

AbstractThe effects of nucleating agents on the morphology and performance of poly(vinylidene fluoride) (PVDF) microporous membranes via thermally induced phase separation were investigated. The nucleating agents studied were dicyclohexyl benzene amide (TMB‐5), 2,2‐methylene bis(4,6‐tertiary butyl phenol) sodium phosphate (TMP‐1), and 1,3 : 2,4‐di‐p‐methylbenzylidene sorbitol (DM–LO). Light transmittance experiments and differential scanning calorimetry (DSC) were performed to obtain phase diagrams of PVDF/tributyl citrate/di(2‐ethylhexyl) phthalate/nucleating agent doped solutions. The morphology and performance of the prepared PVDF microporous membranes were characterized with scanning electron microscopy and microfiltration experiments. The results show that the thermodynamics of liquid–liquid phase separation were not affected by the addition of the nucleating agents, but solid–liquid phase separation was influenced. The system with 0.3 wt % TMB‐5 had the fastest crystallization rate and a better nucleation ability. The PVDF microporous membranes had a partly closed, lacy bicontinuous structure with TMP‐1 and DM–LO, whereas the membrane with 0.3 wt % TMB‐5 had an interconnected bicontinuous structure. The pore size distribution became narrower with the addition of nucleating agent. With 0.3 wt % TMB‐5, the membrane had the minimum mean pore size (0.095 μm), a porosity of 80.3%, and a pure water flux of 270 L·m−2·h−1; these values were higher than those of the pure PVDF membrane. The performances of the membranes decreased with additions of TMB‐5 of greater than 0.3 wt %. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Solvent‐free cyanoethylation of selected alcohols using amberlyst A‐21 polymer resin
Authors: Trinadh Mummuluri , Rajasekhar Tota , Bhadru Bhukya , Gopinath Jonnalagadda , Santosh Vundadi , Reddy Basireddy V. Subba , Sainath Annadanam V.Sesha 
Published: July 2012

AbstractSolvent‐free cyanoethylation of selected alcohols with acrylonitrile (AN) using a weakly basic polymer resin, Amberlyst A‐21 (AA‐21) was studied at 75°C. The conversion of primary alcohols, 1‐octadecanol, hexane‐1,6‐diol, pentaerythritol, but‐2‐yne‐1,4‐diol, N‐methyldiethanolamine, triethanolamine and diethanolamine is higher than secondary alcohols, isopropanol and glycerol in the presence of polymer resin. Of various alcohols, but‐2‐yne‐1,4‐diol gave the product in high conversion (87%) in cyanoethylation with a polymer resin/AN weight ratio of 0.04. The polymer resin showed recycling ability only in two cycles to produce cyanoethylated product from diethanolamine. In case of 1‐octadecanol, hexane‐1,6‐diol, and N‐methyldiethanolamine with AN under similar conditions, no recycling ability was observed. Thermally treated polymer resin at 75°C afforded the product in lower conversion (55%) whereas the same product was obtained in 69% when fresh polymer resin was used in cyanoethylation of 1‐octadecanol. No catalytic effect was observed for polymer resin treated at 100°C. Fourier transform infrared (FTIR) spectra showed CN stretching at 2248 cm−1 for the polymer resin collected after the reaction which was caused by the AN binding on polymer resin during the reaction. As per thermogravimetric curves, 5% weight loss was observed at 201°C for recovered resin and at 161°C for polymer resin treated at 100°C. Scanning electron microscope images confirmed the AN binding on polymer beads after catalytic activity. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Nonisothermal crystallization behaviors of poly(3‐hexylthiophene)/reduced graphene oxide nanocomposites
Authors: Yang Ziping , Lu Hongbin 
Published: July 2012

AbstractPoly(3‐hexylthiophene) (P3HT)/reduced graphene oxide (rGO) nanocomposites were prepared through in situ reduction of graphene oxide in the presence of P3HT. The nonisothermal crystallization behaviors of P3HT and P3HT/rGO nanocomposites were investigated by differential scanning calorimetry. The Avrami, Ozawa, and Mo models were used to analyze the nonisothermal kinetics. The addition of rGO remarkably increased the crystallization peak temperature and crystallinity of P3HT, but the crystallization half‐time revealed little variation. The crystallization activation energies were calculated by the Kissinger equation. The results suggested that rGO plays a twofold role in the nonisothermal crystallization of P3HT, that is, rGO promotes the crystallization of P3HT as nucleating agent, and meanwhile, it also restricts the motion of P3HT chains. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Effect of magnetic field on discotic nematic liquid crystalline polymers under simple shear flow
Authors: Fu Shu‐Fang , Jing‐Bai  , Wang Xuan‐Zhang 
Published: July 2012

AbstractThe effect of magnetic field on the discotic nematic liquid crystalline polymers (LCPs) is analyzed with the extended Doi theory, in which the molecular shape parameter (β) is defined at −1.0. The evolution equation for the probability function of the discotic nematic LCP molecules is solved without any closure approximations. The transition among flow‐orientation modes, such as tumbling, wagging, and aligning defined similar to the rodlike LCPs, is strongly affected by the magnetic fields. The new aligning flow‐orientation mode observed for the rodlike LCPs under magnetic fields also can be investigated in the lower shear rate region. On the other hand, the effect of magnetic fields parallel to the x‐ and y‐axis on the time‐averaged first and second normal stress differences (
$\bar N_1^*$,
$\bar N_2^*$) are also studied. It can be seen that the shear rate regions of the sign changes of
$\bar N_1^*$,
$\bar N_2^*$
are completely contrary to those conclusions achieved for the rodlike LCPs. In addition, the absolute values of
$\bar \eta ^*$
increase with the magnetic field strength in the lower shear rate range owing to the new aligning flow‐orientation mode. Finally, the flow‐phase diagram versus β is also discussed. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Thermal response of an electric heating rapid heat cycle molding mold and its effect on surface appearance and tensile strength of the molded part
Authors: Wang Guilong , Zhao Guoqun , Guan Yanjin 
Published: July 2012

AbstractRapid heat cycle molding (RHCM) is a newly developed injection molding technology in recent years. In this article, a new electric heating RHCM mold is developed for rapid heating and cooling of the cavity surface. A data acquisition system is constructed to evaluate thermal response of the cavity surfaces of the electric heating RHCM mold. Thermal cycling experiments are implemented to investigate cavity surface temperature responses with different heating time and cooling time. According to the experimental results, a mathematical model is developed by regression analysis to predict the highest temperature and the lowest temperature of the cavity surface during thermal cycling of the electric heating RHCM mold. The verification experiments show that the proposed model is very effective for accurate control of the cavity surface temperature. For a more comprehensive analysis of the thermal response and temperature distribution of the cavity surfaces, the numerical‐method‐based finite element analysis (FEA) is used to simulate thermal response of the electric heating RHCM mold during thermal cycling process. The simulated cavity surface temperature response shows a good agreement with the experimental results. Based on simulations, the influence of the power density of the cartridge heaters and the temperature of the cooling water on thermal response of the cavity surface is obtained. Finally, the effect of RHCM process on surface appearance and tensile strength of the part is studied. The results show that the high‐cavity surface temperature during filling stage in RHCM can significantly improve the surface appearance by greatly improving the surface gloss and completely eliminating the weld line and jetting mark. RHCM process can also eliminate the exposing fibers on the part surface for the fiber‐reinforced plastics. For the high‐gloss acrylonitrile butadiene styrene/polymethyl methacrylate (ABS/PMMA) alloy, RHCM process reduces the tensile strength of the part either with or without weld mark. For the fiber‐reinforced plastics of polypropylene (PP) + 20% glass fiber, RHCM process reduces the tensile strength of the part without weld mark but slightly increases the tensile strength of the part with weld mark. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Ultrastructural and Morphological Characteristics of Human Anterior Cruciate Ligament and Hamstring Tendons
Authors: Zhu Jingxian , Zhang Xin , Ma Yong , Zhou Chunyan , Ao yingfang 
Published: July 2012

AbstractHamstring tendons are a commonly used substitute for anterior cruciate ligament (ACL) reconstruction. Ligaments and tendons are similar in composition but the ACL is more complex than hamstring tendons in function and gross morphology, which are highly dependent on its structure and ultrastructure. The purpose of this study was to compare the morphology and ultrastructure of normal human ACL and hamstring tendons, including the cell type and arrangement, expression level of proteoglycans, diameter, and density of collagen fibrils. Twenty semitendinosus or gracilis tendons and 20 ACL specimens were harvested from patients with ACL rupture or osteoarthritis undergoing routine total knee arthroplasty. The specimens were examined histologically and the ultrastructure was observed using scanning and transmission electron microscopy. Semitendinosus and gracilis tendons showed a homogeneous arrangement of collagen fibers and cell type. They had lower fibril density and more widely distributed fibril diameters. In the ACL, there was a more complex arrangement of collagen fibers, distribution of proteoglycans and different cell types. Electronic microscopy demonstrated a combination of parallel, helical and nonlinear networks of ACL fibrils, and fibril diameters were smaller and more nonuniform. This study compared the anatomy of normal human ACL and hamstring tendons, which may provide a standard for evaluating hamstring tendons grafts after ACL reconstruction and may facilitate the application of hamstring tendons in clinical applications. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
Cortical Bone Response to the Presence of Load‐Bearing Percutaneous Osseointegrated Prostheses
Authors: Jeyapalina Sujee , Beck James Peter , Bachus Kent N. , Bloebaum Roy D. 
Published: July 2012

AbstractAlthough the current percutaneous osseointegrated (OI) prosthetic attachment systems are novel clinical treatments for patients with limb loss, there have only been limited translational studies undertaken to date. To bridge this knowledge gap, from a larger study group of 86 animals that were implanted with a novel percutaneous OI implant construct, 33 sheep were randomly selected from the 0‐, 3‐, 6‐, 9‐ and 12‐month groups for histomorphometric analyses of periprosthetic cortical bone tissue. At necropsy, implanted and nonimplanted limbs were harvested and processed for the evaluation of cortical bone porosity and mineral apposition rate (MAR). The data showed a maximum increase in bone porosity within the first 3 months following implantation and then a progressive reduction in porosity to the baseline steady‐state (“Time 0”) value by 12 months. The data further verified that the MAR increased during the first 6 months of implantation, reaching a plateau between 6 and 9 months, followed by a progressive decline to the baseline steady state. It was concluded that clinical load bearing and falls precautions, taken during the first 3–6 months following percutaneous OI device implantation surgery, could greatly limit bone fractures during this vulnerable time of increasing cortical bone porosity. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
Morphometry and Patterns of Lamellar Bone in Human Haversian Systems
Authors: Pazzaglia Ugo E. , Congiu Terenzio , Marchese Marcella , Spagnuolo Francesco , Quacci Daniela 
Published: July 2012

AbstractThe lamellar architecture of secondary osteons (Haversian systems) has been studied with scanning electron microscopy (SEM) in transverse sections of human cortical bone. Na3PO4 etching was used to improve the resolution of the interface between neighboring lamellae and the precision of measurements. These technical improvements permitted testing of earlier morphometry assumptions concerning lamellar thickness while revealing the existence of different lamellar patterns. The mean lamellar thickness was 9.0 ± 2.13 μm, thicker and with a wider range of variation with respect to earlier measurements. The number of lamellae showed a direct correlation with the lamellar bone area, and their thickness had a random distribution for osteonal size classes. The circular, concentrical pattern was the more frequently observed, but spiral and crescent‐moon‐shaped lamellae were also documented. Selected osteons were examined by either SEM or SEM combined with polarized light microscopy allowing comparisons of corresponding sectors of the osteon. The bright bands observed with polarized light corresponded to the grooves observed in etched sections by SEM. The dark bands corresponded to the lamellar surface with the cut fibrils oriented approximately longitudinally along the central canal axis. However, lamellae with large and blurred bright bands could be observed, which did not correspond to a groove observed by SEM. These findings are in contrast with the assumption that all the fibril layers within a lamella are oriented along a constant and unchangeable angle. The different lamellar patterns may be explained by the synchronous or staggered recruitment and activation of osteoblasts committed to the osteon's completion. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
Discrepancies between patients and physicians in their perceptions of rheumatoid arthritis disease activity
Authors: Studenic Paul , Radner Helga , Smolen Josef S. , Aletaha Daniel 
Published: July 2012

AbstractObjectivePatients and physicians often differ in their perceptions of rheumatoid arthritis (RA) disease activity, as quantified by the patient's global assessment (PGA) and by the evaluator's global assessment (EGA). The purpose of this study was to explore the extent and reasons for this discordance.MethodsWe identified variance components for the PGA and EGA in RA patients who were starting therapy with methotrexate in an academic outpatient setting. We analyzed predictors of the observed discrepancy in these measures (calculated as the PGA minus the EGA) and in their changes (calculated as the PGAchange minus the EGAchange).ResultsWe identified 646 RA patients, and among them, 77.4% of the variability in the PGA and 66.7% of the variability in the EGA were explainable. The main determinants for the PGA were pain (75.6%), function (1.3%, by Health Assessment Questionnaire), and number of swollen joints (0.5%); those for the EGA were the number of swollen joints (60.9%), pain (4.5%), function (0.6%), C‐reactive protein (0.4%), and the number of tender joints (0.3%). Increased pain led to a discrepancy toward worse patient perception, while increased numbers of swollen joints led to a discrepancy toward worse evaluator perception, both explaining 65% of the discordance between the PGA and the EGA. Likewise, changes in pain scores and numbers of swollen joints proved to be the main determinants for discrepant perceptions of changes in RA disease activity, explaining 34.6% and 12.5% of the discordance, respectively.ConclusionThe most significant determinants for the cross‐sectional and longitudinal discrepancy between the PGA and the EGA are pain and joint swelling, respectively. Understanding the reasons for a discordant view of disease activity will help to facilitate the sharing of decision‐making in the management of RA.
CO2‐Activation for γ‐Butyrolactones and Its Application in the Total Synthesis of (±)‐Heteroplexisolide E
Authors: Li Suhua , Ma Shengming 
Published: July 2012

AbstractAn efficient nickel(0)‐catalyzed highly regio‐ and stereoselective hydrocarboxylation of homopropargylic alcohols with ZnEt2 in the presence of CO2 (1 atm, balloon) to synthesize α‐alkylidene‐γ‐butyrolactones is described. The catalyst is highly active and can be applied for the synthesis of (optically active) mono‐ or bicyclic α‐alkylidene‐γ‐butyrolactones with excellent regio‐ and stereoselectivity and good functional group tolerance. The potential of the reaction has been demonstrated in the first synthesis of (±)‐heteroplexisolide E.
Ultrafast relaxation dynamics of solvated electrons in water
Authors: Hertwig A. , Hippler H. , Unterreiner A.N. , Vöhringer P. 
Published: July 2012

AbstractThe relaxation dynamics of excess electrons in a water jet between 5 and 70°C have been investigated on an ultrashort timescale. We have probed the transient absorption of the system immediately after UV multiphoton‐ionization with a 266 nm ultrashort laser pulse and a time resolution of about 50 fs. Probe wavelengths ranging from 450 to 1000 nm have been provided by a generated white‐light continuum. The data suggest a superposition of geminate recombination of the solvated electrons with their original counter‐ions and of relaxation into thermal equilibrium. Relaxation into thermal equilibrium is the much faster process and is completed after about 6 ps while the geminate recombination is much slower, temperature independent, and prevails for at least 100 ps. The here postulated interpretation of the data clearly shows that no other transient states than “hot solvated electrons” are required for an understanding of the observed ultrafast dynamics within our time resolution.
Bromide adsorption on silver in alkaline solution: A surface analytical study
Authors: Lützenkirchen‐Hecht D. , Strehblow H.‐H. 
Published: July 2012

AbstractThe electrochemical double layer on Ag in alkaline NaBr solutions was investigated ex situ with x‐ray photo‐electron spectroscopy (XPS). The specimen were removed from the electrolyte with hydrophobic surfaces and under potential control. Potential dependent surface concentrations of the adsorbed anions, cations and the surface excess charge, as well as the amount of adsorbed water were determined. The results obtained for the double layer on Ag in 1 M NaOH+0.1 M NaBr and 1 M NaOH+10−3 M NaBr were compared with alkaline chloride solutions and pure 1 M NaOH. We found evidence for a specific adsorption of hydroxide ions in the basic electrolyte; i.e. the OH−‐surface concentration has to be considered for a proper determination of the cat‐ionic excess charge and the potential of zero charge. Compared to the alkaline chloride solution and pure NaOH, however, an underpotential Ag‐oxide formation below the Nernst‐potential of oxide formation was not observed for the alkaline NaBr solutions, i.e. adsorbed Br− ions inhibit the electrochemical Ag(I) oxide formation.
Swelling properties of colloidal poly(N‐Isopropylacrylamide) microgels in solution
Authors: Kratz Karl , Eimer Wolfgang 
Published: July 2012

AbstractThe volume phase transition of colloidal poly(N‐isopropylacrylamide) microgels with different cross‐linker density has been investigated by dynamic light scattering and scanning electron microscopy. The surfactant‐free emulsion polymerization provides spherical microgel particles with a very narrow size distribution. The amount of cross‐linker has no significant influence on the final hydrodynamic radius in the swollen state at low temperature, but the uniform shape of the dried particles declines for cross‐linker density below 1%. The volume change increases with decreasing connectivity of the gel which is due to topological constraints of the polymer network. While the critical temperature does not vary significantly, a change in the nature of the transition process from a continuous to a more discontinuous volume change was observed.
Orientational dynamics of hydrogen‐bonded liquids – A comparative study of dielectric and nuclear magnetic relaxation in n‐butanol‐tetrachloromethane mixtures
Authors: Nadolny Holger , Volmari Andreas , Weingärtner Hermann 
Published: July 2012

AbstractComplex dielectric spectra up to 20 GHz are measured at 25°C for n‐butanol tetrachloromethane mixtures. Within this frequency range the spectra can be described by two Debye‐processes. Their relaxation times τ(1)1 and τ(2)1 are compared with the hypothetical single‐particle relaxation time of the dipoles τs1 estimated from deuteron magnetic relaxation rates in these mixtures. The results indicate a collective nature of the primary relaxation time τ(1)1 due to cooperative motion of several molecules. Although not accurate in detail, some theoretical models can reproduce major features of the concentration dependence of τ(1)1. In these models, τ(1)1 is coupled to τs1 via the Kirkwood correlation factor g1 which can be determined independently from the static permittivity. There is no obvious interrelation between τs1 and the secondary relaxation time τ(2)1 the nature of which remains puzzling.
Synthesis and luminescent properties of novel BaGd2O4:Eu3+ scintillating phosphor
Authors: Sun Xin‐Yuan , Wang Wen‐Feng , Sun Shou‐Qiang , Lin Liang‐Wu , Li De‐Yi , Zhou Ling‐Ping 
Published: July 2012

ABSTRACTBaGd2‐xO4:xEu3+ and Ba1‐yGd1.79‐2yEu0.21Na3yO4 phosphors were synthesized at 1300°C in air by conventional solid‐state reaction method. Phosphors were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence excitation (PLE) spectra, photoluminescence (PL) spectra and thermoluminescence (TL) spectra. Optimal PL intensity for BaGd2‐xO4:xEu3+ and Ba1‐yGd1.79‐2yEu0.21Na3yO4 phosphors at 276 nm excitation were found to be x = 0.24 and y = 0.125, respectively. The PL intensity of Eu3+ emission could only be enhanced by 1.3 times with incorporation of Na+ into the BaGd2O4 host. Enhanced luminescence was attributed to the flux effect of Na+ ions. However, when BaGd2O4:Eu3+ phosphors were codoped with Na+ ions, the induced defects confirmed by TL spectra impaired the emission intensity of Eu3+ ions. Copyright © 2012 John Wiley & Sons, Ltd.