bluuebunny/crossref_metadata_2025_split huggingface dataset:
The ontogeny of Holocene and Late Pleistocene human postcranial strength
Authors: Cowgill Libby W. 
Published: June 2009

AbstractWhile a wide variety of studies have focused on population variation in adult cross‐sectional properties, relatively little is known about population variation in postcranial robusticity in immature individuals. Furthermore, the age at which the population differences readily detected in adults manifest during growth is also unknown. This research addresses these gaps in our current understanding through the analysis of immature humeral and femoral long bone strength. Cross‐sectional geometry was used to compare the developmental trajectories of diaphyseal strength in Late Pleistocene Neandertal and modern human subadults to a sample of immature humans from seven geographically diverse Holocene populations. Population differences in size‐standardized cross‐sectional properties appear to be systemic and develop very early in ontogeny in the Holocene sample. In many cases, these differences are present before one year of age. In general, the Late Pleistocene fossil samples fit within the range of recent human variation in long bone strength. Population differences detected here are likely related to a combination of factors including activity patterns, genetic propensities, and nutritional status. These results highlight the complex mosaic of processes that result in adult postcranial robusticity, and suggest that further exploration of the developmental interplay between intrinsic and extrinsic influences on skeletal robusticity will likely enhance our understanding of adult postcranial morphology. Am J Phys Anthropol 2010. © 2009 Wiley‐Liss, Inc.
Cleaner Continuous Photo‐Oxidation Using Singlet Oxygen in Supercritical Carbon Dioxide
Authors: Bourne Richard A. , Han Xue , Poliakoff Martyn , George Michael W. 
Published: June 2009

AbstractHochdruck im Fokus: Ein Milliliter‐Reaktor wurde entwickelt, um überkritisches CO2 für kontinuierliche Photooxidationen nutzen zu können. Der Wechsel von einer traditionellen Batch‐Reaktion im Mikroliterbereich zu einer achtstündigen Reaktion im neuen Reaktor entsprach einer Ansatzvergrößerung um den Faktor 3000 bei der Oxidation von α‐Terpinen (siehe Bild).magnified image
Enantioselective Linchpin Catalysis by SOMO Catalysis: An Approach to the Asymmetric α‐Chlorination of Aldehydes and Terminal Epoxide Formation
Authors: Amatore Muriel , Beeson Teresa D. , Brown Sean P. , MacMillan David W. C. 
Published: June 2009

AbstractDreh‐ und Angelpunkt: Erstmals wurde eine SOMO‐Aktivierung genutzt, um Aldehyde in α‐Stellung zu chlorieren. Diese Umwandlung lässt sich als Teil eines „Linchpin“‐Katalyseprozesses einsetzen, der die enantioselektive Synthese terminaler Epoxide ermöglicht (siehe Schema).magnified image
A Facile Route to Aryl Boronates: Room‐Temperature, Copper‐Catalyzed Borylation of Aryl Halides with Alkoxy Diboron Reagents
Authors: Kleeberg Christian , Dang Li , Lin Zhenyang , Marder Todd B. 
Published: June 2009

AbstractEine einfache und effektive kupferkatalysierte Borylierung von Arylhalogeniden, einschließlich elektronenreicher und sterisch gehinderter Arylbromide, mit Alkoxydiborreagentien gelingt unter milden Bedingungen (siehe Schema). DFT‐Rechnungen legen nahe, dass eine σ‐Bindungsmetathese zwischen einer Kupfer‐Boryl‐Zwischenstufe und dem Arylhalogenid zum Arylboronat führt.magnified image
Self‐Coupling of a 4‐H‐Butatrienylidene Tungsten Complex
Authors: Semenov Sergey N. , Blacque Olivier , Fox Thomas , Venkatesan Koushik , Berke Heinz 
Published: June 2009

AbstractRendezvous zweier Wolfram‐Fragmente: Ein 4‐H‐Butatrienyliden‐Komplex des Wolframs wurde isoliert und strukturell charakterisiert. Der Komplex geht eine einmalige Selbstkupplung ein, die zu einem Dimer mit kreuzkonjugiertem π‐System sowie elektrochemisch und magnetisch aktiven Metallzentren führt (siehe Bild; P violett, O rot).magnified image
A Facile Template Approach to High‐Nuclearity Silver(I) Alkynyl Clusters
Authors: Bian Shu‐Dan , Wu Hua‐Bin , Wang Quan‐Ming 
Published: June 2009

AbstractErdnussförmig: Eine einfache Synthese großer Silbercluster nutzt Anionen als Template. Die Zahl an Silberatomen im Cluster lässt sich über die Größe des Templats und die Eigenschaften der Alkinylliganden einstellen. Für den größten Cluster mit 35 Silber(I)‐Zentren wurden Chromat‐Ionen als Templat eingesetzt (siehe Bild).magnified image
Hydrogen‐Bonding Catalysts Based on Fluorinated Alcohol Derivatives for Living Polymerization
Authors: Coulembier Olivier , Sanders Daniel P. , Nelson Alshakim , Hollenbeck Andrew N. , Horn Hans W. , Rice Julia E. , Fujiwara Masaki , Dubois Philippe , Hedrick James L. 
Published: June 2009

AbstractRecognize this! A hydrogen‐bonding motif based on hexafluorinated alcohol derivatives (see picture; O red, F yellow) activates electrophilic substrates. The catalytic activity of the hydrogen‐bonded systems was demonstrated for the ring‐opening polymerization of a variety of strained heterocycles. Narrowly dispersed polymers with predictable molecular weights were obtained with end‐group fidelity.magnified image
Probing the Inner Space of Resorcinarene Molecular Capsules with Nitroxide Guests
Authors: Mileo Elisabetta , Yi Song , Bhattacharya Papri , Kaifer Angel E. 
Published: June 2009

AbstractIn quarantine: Nitroxide spin probes are encapsulated by hexameric resorcinarene molecular capsules in dichloromethane solutions (see picture). A substantial reduction in the tumbling rates occurs upon encapsulation of two cationic probes and one neutral probe. As the molecular volume of the probe increases, the tumbling rate of the probe reflects the overall tumbling rate of the entire supramolecular assembly.magnified image
Synthesis and Characterization of a Photoluminescent Nanoparticle Based on Fullerene–Silica Hybridization
Authors: Jeong Jinyoung , Cho Miyoung , Lim Yong Taik , Song Nam Woong , Chung Bong Hyun 
Published: June 2009

AbstractBright lights: Fullerene–silica hybrid nanoparticles have bright photoluminescence, high photostability, and low cytotoxicity, which are assets for bioimaging agents. The origin of the photoluminescence of the nanoparticle is the C–O–Si bond (see picture).magnified image
A Facile Route to Aryl Boronates: Room‐Temperature, Copper‐Catalyzed Borylation of Aryl Halides with Alkoxy Diboron Reagents
Authors: Kleeberg Christian , Dang Li , Lin Zhenyang , Marder Todd B. 
Published: June 2009

AbstractA simple but effective copper‐catalyzed borylation of aryl halides, including electron‐rich and sterically hindered aryl bromides, with alkoxy diboron reagents occurs under mild conditions (see scheme). Preliminary DFT studies of the mechanism suggest that σ‐bond metathesis between a copper–boryl intermediate and the aryl halide generates the aryl boronate product.magnified image
Palladium‐Catalyzed Direct Arylation of Cyclic Enamides with Aryl Silanes by sp2 CH Activation
Authors: Zhou Hai , Xu Yun‐He , Chung Wan‐Jun , Loh Teck‐Peng 
Published: June 2009

AbstractIt does get in! A fluoride‐assisted direct cross‐coupling of cyclic enamides with trialkoxy aryl silanes by a palladium‐catalyzed CH activation leads to a wide range of enamides in yields of up to 95 %.magnified image
Nanofiber organic semiconductors: The effects of nanosize on the electrical charge transport and optical properties of bulk polyanilines
Authors: Yakuphanoglu F. , Mehrotra R. , Gupta A. , Muñoz M. 
Published: June 2009

AbstractThe electrical transport, optical, and microstructural properties of bulk polyaniline (PANI) and nano‐PANIs were investigated. A field emission scanning electron microscopy (SEM) image of bulk PANI showed macroscopic and aggregated granular particles. A SEM image of the nanostructured PANI showed the formation of one‐dimensional nano/microstructures. The formation of nanofibers was observed from the transmission electron microscopy image. The electrical conductivities of the bulk and nanostructured PANIs increased with increasing temperature, which indicated semiconductor behavior. The electrical conductivities of the bulk and nanostructured PANIs at room temperature were found to be 2.12 × 10−5 and 1.80 × 10−2 S/cm, respectively. The electrical conductivity of the nanostructured PANI was about 850 times higher than that of the bulk PANI. The obtained band gaps of the bulk and nanostructured PANIs were determined from diffuse reflectance measurements and were found to be 3.27 and 2.41 eV, respectively. The refractive index of the PANI samples changed from 1.3 to 1.61. The obtained results indicate that the electrical and optical properties of the PANI were inherently dependent on the nanostructure. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
A simple method for the preparation of stable chitooligomers
Authors: Zeng Lintao , Qin Caiqin , Li Wei , Wang Wei 
Published: June 2009

AbstractThe chitosan was degraded by the cheap, efficient, and commercially available enzymes in hydrochloric acid solution. The effect of molar ratio of added HCl to NH2 of chitosan on the degradation was investigated, and the favorable ratio was between 0.50 and 0.95. The chitooligomer hydrochlorides were directly prepared by this simple method. The chitooligomer hydrochlorides were characterized by thermogravimetric analysis, differential thermal analysis, and Fourier transform infrared. These results show that the obtained chitooligomer hydrochlorides were much more stable than the chitooligomer acetates. This preparation procedure of chitooligomer hydrochlorides was simple and cheap, and helpful for the preservation of chitooligomers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
New generation polymeric nanospheres for catalase immobilization
Authors: Akgöl Sinan , Öztürk Nevra , Denizli Adil 
Published: June 2009

AbstractMonosize poly(2‐hydroxyethyl methacrylate‐co‐N‐methacryloly‐L‐histidinemethylester) [mon‐poly(HEMA‐MAH)] nanospheres were prepared via surfactant‐free emulsion polymerization method. L‐Histidine groups of the mon‐poly(HEMA‐MAH) nanospheres were chelated with Fe3+ ions. Mon‐poly(HEMA‐MAH) nanospheres were characterized by Fourier transform infrared spectroscopy, proton NMR, and scanning electron microscopy. Particle size of the mon‐poly(HEMA‐MAH) nanospheres was measured by Zeta Sizer. Elemental analysis of MAH for nitrogen was estimated as 0.94 mmol/g polymer. The catalase immobilized onto the mon‐poly(HEMA‐MAH)–Fe3+ nanospheres resulted in increasing the enzyme stability with time. Optimum operational temperature for both immobilized preparations was the same, and the temperature profiles of the immobilized preparations were significantly broader. It was observed that enzyme could be repeatedly adsorbed and desorbed on the mon‐poly(HEMA‐MAH)–Fe3+ nanospheres without loss of adsorption capacity or enzymic activity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation of poly(ester imide) ultrafine fibers by gas‐jet/electrospinning
Authors: Wang Bing , Yao Yongyi , Peng Jinrong , Lin Yi , Liu Wenlong , Luo Yang , Xiang Ruili , Li Ruixia , Wu Dacheng 
Published: June 2009

AbstractIn this study, ultrafine fibers of poly(ester imide) (PEI) were produced by gas‐jet/electrospinning of its solutions in mixtures of phenol and dichloromethane (DCM). The process parameters, including the solution concentration, gas flow rate, applied voltage, tip‐to‐collector distance (TCD), and inner diameter of the metal needle, were investigated by scanning electron microscopy. The results show that the solution concentration, gas flow rate, TCD, and inner diameter of the needle were the most important process parameters influencing the average diameter and morphology of the PEI gas‐jet/electrospun fibers. An increase in the solution concentration resulted in a larger average diameter in the PEI gas‐jet/electrospun fibers. Mixed‐bead fibers were obtained when the concentration of PEI in phenol/DCM was below 20 wt % during gas‐jet/electrospinning. A larger diameter of the capillary and a smaller gas flow rate favored the formation of ultrafine fibers with thicker fibers. Thinner and uniform PEI fibers with an average diameter of 298 nm were formed at a TCD of 25 cm. On the basis of the systematic parameters study, uniform PEI ultrafine fibers with an average diameter of 293 nm were prepared by this gas‐jet/electrospinning with the following optimal process parameters: the concentration of the polymer solution was 20 wt %, the gas flow rate was 10.0 L/min, the applied voltage was 25.0 kV, the TCD was 25 cm, and the inner diameter of the metal needle was 0.24 mm. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
A kinetic analysis on thermal degradation of poly(phenylene sulfide ether)
Authors: Gu Aiqun , Yu Zili , Li Yubao 
Published: June 2009

AbstractThermal degradation of poly(phenylene sulfide ether) (PPSE) was investigated by using thermogravimetry (TG) under air and nitrogen atmosphere. It was found that the existence of oxygen depressed the thermal stability of PPSE and changed the mechanism of thermal degradation. The influences of molecular weight and heating rate on the decomposition of PPSE were also investigated under N2 atmosphere. The results showed that the thermal stability of PPSE was excellent and can be further enhanced by increasing molecular weight. A simple kinetic model concerning two parallel reactions in overall temperature range was proposed to describe the thermal degradation process of PPSE in nitrogen. Kinetic analysis of the dynamic TG curves for PPSE was carried out by using Kissinger, Flynn–Wall–Ozawa, and Coats–Redfern methods. The kinetics of PPSE degradation displayed that the two parallel reactions were in accordance with the first‐order equation. The kinetic model was further validated by comparing the experimental and calculated results. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and characterization of conducting polyaniline prepared by laccase‐catalyzed method in sodium dodecylbenzenesulfonate micellar solutions
Authors: Streltsov Alexander V. , Morozova Olga V. , Arkharova Nataliya A. , Klechkovskaya Vera V. , Staroverova Irina N. , Shumakovich Galina P. , Yaropolov Alexander I. 
Published: June 2009

AbstractEnzymatic polymerization of aniline was performed in micellar solutions of the anionic surfactant sodium dodecylbenzenesulfonate (SDBS). High‐redox–potential oxidase–laccase isolated from the fungi, Trametes hirsuta, was used as a catalyst in oxidative polymerization of aniline, the atmospheric oxygen serving as an oxidizing agent. It is shown that the laccase‐catalyzed reaction of monomer polymerization is kinetically controllable and its mechanism is very distinctly different from that of chemical polymerization. The synthesized PANI/SDBS complexes were characterized using Fourier transform infrared and UV–vis spectroscopy, cyclic voltammetry, termogravimetry, transmission electron microscopy, and electron diffraction. The antistatic properties of the prepared PANI/SDBS composite were also studied. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Improvement of the properties of ground tire rubber (GTR)‐filled nitrile rubber vulcanizates through plasma surface modification of GTR powder
Authors: Zhang Xinxing , Zhu Xiaoqing , Liang Mei , Lu Canhui 
Published: June 2009

AbstractThe surface modification of ground tire rubber (GTR) powder to enhance its adhesion to nitrile rubber (NBR) vulcanizates was investigated. The hydrophobic surface of GTR powder has been transformed to a hydrophilic one through atmospheric pressure dielectric barrier discharge (DBD). The water contact angle dropped markedly from 116 to 0° after being treated for more than 10 s. Attenuated total reflectance Fourier transform infrared spectral (ATR‐FTIR) studies revealed the increase in peak intensity at 3298 and 1640 cm−1 that correspond to OH and CC, respectively, on the surface of the GTR powder. The X‐ray photoelectron spectroscopic (XPS) analysis further confirmed the presence of oxygen containing polar functional groups on the surface of the GTR powder after atmospheric plasma treatment. The improvement in tensile strength and tear strength was observed for the modified GTR‐filled NBR vulcanizates, which is attributed to the enhanced interfacial interaction between modified GTR and NBR matrix. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Removal of basic dyes from aqueous solutions by crosslinked‐acrylic acid/acrylamidopropane sulfonic acid hydrogels
Authors: Akkaya M. Çağil , Emik Serkan , Güçlü Gamze , İyim Tülin Banu , Özgümüş Saadet 
Published: June 2009

AbstractIn this study, Acrylic acid (AA)/2‐acrylamido‐2‐methlypropane sulfonic acid (AMPS) hydrogels were prepared by free radical polymerization in aqueous solutions of AA, AMPS, and N,N‐methylenebisacrylamide (NMBA) as crosslinker. Potassium persulfate (PPS)/potassium bisulfide (PBS) were used as initiator and accelerator pair. The water absorption capacities and dye adsorption properties of the hydrogels were investigated. Adsorption properties of the hydrogels were evaluated by depending on different adsorption conditions such as different initial dye concentration and contact time. The concentrations of the dyes were determined using UV/Vis Spectrophotometer at wavelength 530 nm for safranine T (ST) and 622 nm for brilliant cresyl blue (BCB). Adsorption kinetic studies showed that pseudo‐first order kinetic model is suitable to explain the adsorption kinetic data of the hydrogels. Langmuir and Freundlich isotherm models were used to describe adsorption data. The result revealed that the adsorption of basic dyes onto hydrogels fit very well both Langmuir and Freundlich isotherms. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Nonisothermal crystallization and melting behavior of poly(ε‐caprolactone)‐b‐poly(ethylene glycol)‐b‐poly(ε‐caprolactone) by DSC analysis
Authors: Wei Zhiyong , Yu Fengyun , Chen Guangyi , Qu Chao , Wang Pei , Zhang Wanxi , Liang Jicai , Qi Min , Liu Lian 
Published: June 2009

AbstractNonisothermal crystallization kinetics and melting behavior of poly(ε‐caprolactone)‐b‐poly(ethylene glycol)‐b‐poly(ε‐caprolactone) triblock copolymer (PCL‐PEG‐PCL), in which the weight fraction of the PCL block is 0.87, has been studied by differential scanning calorimetry (DSC). The nonisothermal crystallization data at various cooling rates are analyzed with the Ozawa, modified Avrami, and Mo models. The modified Avrami and Mo models were found to describe the nonisothermal crystallization processes fairly well. The values of the Avrami exponent n were near three, suggesting the crystallization process with a three‐dimensional crystallite growth by heterogeneous nucleation mechanism. The crystallization activation energy estimated from the cooling scans using Kissinger's method was 168.9 KJ/mol. The phenomenon of the double melting behavior was observed for the PCL block during melting process after nonisothermal crystallization, being the reflection of a complicated crystallization process and the existence of the amorphous middle PEG block. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Hydrolytic stability of cured urea‐formaldehyde resins modified by additives
Authors: Abdullah Zaimatul Aqmar , Park Byung‐Dae 
Published: June 2009

AbstractUrea‐formaldehyde (UF) resins are prone to hydrolysis that results in low‐moisture resistance and subsequent formaldehyde emission from UF resin‐bonded wood panels. This study was conducted to investigate hydrolytic stability of modified UF resins as a way of lowering the formaldehyde emission of cured UF resin. Neat UF resins with three different formaldehyde/urea (F/U) mole ratios (1.4, 1.2, and 1.0) were modified, after resin synthesis, by adding four additives such as sodium hydrosulfite, sodium bisulfite, acrylamide, and polymeric 4,4′‐diphenylmethane diisocyanate (pMDI). All additives were added to UF resins with three different F/U mole ratios before curing the resin. The hydrolytic stability of UF resins was determined by measuring the mass loss and liberated formaldehyde concentration of cured and modified UF resins after acid hydrolysis. Modified UF resins of lower F/U mole ratios of 1.0 and 1.2 showed better hydrolytic stability than the one of higher F/U mole ratio of 1.4, except the modified UF resins with pMDI. The hydrolytic stability of modified UF resins by sulfur compounds (sodium bisulfate and sodium hydrosulfite) decreased with an increase in their level. However, both acrylamide and pMDI were much more effective than two sulfur compounds in terms of hydrolytic stability of modified UF resins. These results indicated that modified UF resin of the F/U mole ratio of 1.2 by adding acrylamide was the most effective in improving the hydrolytic stability of UF resin. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
The properties of reactive hot melt polyurethane adhesives modified with novel thermoplastic polyurethanes
Authors: Kim Tae K. , Kim Byung K. , Kim Yong S. , Cho Yang L. , Lee Sang Y. , Cho Youn B. , Kim Joe H. , Jeong Han M. 
Published: June 2009

AbstractA reactive hot melt adhesive (RHMA) consisting of thermoplastic polyurethane (TPU) was modified with sodium montmorillonite (Na‐MMT) intercalated with poly(ethylene glycol) (PEG), and their effects on the adhesion, rheological, and mechanical properties of the RHMA were examined. The Na‐MMT intercalated with PEG (Na‐MMT/PEG) effectively enhanced the initial bond strength development of the RHMA, although the amounts of Na‐MMT/PEG in the RHMA were less than 0.2%. The increase of the complex viscosity and pseudo‐solid like behavior observed at low shear rate indicates that there are intimate interactions between the RHMA molecules and Na‐MMT/PEG. The improved modulus and tensile strength of the cured RHMA film in the presence of Na‐MMT/PEG demonstrates that Na‐MMT/PEG effectively reinforced the RHMA. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
GDNF Expression in Terminal Schwann Cells Associated With the Periodontal Ruffini Endings of the Rat Incisors During Nerve Regeneration
Authors: Ohishi Megumi , Harada Fumiko , Rahman Farhana , Saito Isao , Kawano Yoshiro , Nozawa‐Inoue Kayoko , Maeda Takeyasu 
Published: June 2009

AbstractThe terminal Schwann cells (TSCs) which play crucial roles in regeneration of the periodontal Ruffini endings (RE) exhibit immunoreaction for glial cell line‐derived neurotrophic factor (GDNF). However, no information is available regarding the role of GDNF in the periodontal RE during nerve regeneration. This study was undertaken to examine the changes in GDNF expression in the rat periodontal RE following transection of the inferior alveolar nerve (IAN) using immunohistochemistry for GDNF and S‐100 protein, a marker for the TSCs. We additionally investigated the changes in expression of GDNF in the trigeminal ganglion (TG) at protein and mRNA levels. A transection to IAN induced a disappearance of the TSCs from the alveolus‐related part (ARP), followed by a migration of spindle‐shaped cells with S‐100 but without GDNF immunoreactions into the tooth‐related part (TRP) by postoperative (PO) week 2. At PO week 2, GDNF immunoreacted cellular elements increased in number in the ARP although the spindle‐shaped cells without GDNF reaction remained in the TRP. After PO week 4, many GDNF‐positive TSCs appeared in the ARP though the spindle‐shaped cells vanished from the TRP. A real time RT‐PCR analysis demonstrated the highest elevation of GDNF mRNA in the TG at PO week 2. These findings suggested the involvement of this molecule in the maturation and maintenance of the periodontal RE during regeneration. Taken together with our previous and current studies, it appears that the regeneration of the periodontal RE is controlled by multiple neurotrophins in a stage‐specific manner. Anat Rec, 2009. © 2009 Wiley‐Liss, Inc.