bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of Thin, Oriented Zeolite A Membranes on a Macroporous Support
Authors: Kuzniatsova Tatsiana A. , Mottern Matthew L. , Chiu William V. , Kim Yanghee , Dutta Prabir K. , Verweij Henk 
Published: March 2008

AbstractContinuous, thin, oriented zeolite A membranes are produced by a two‐step synthesis on macroporous α‐Al2O3 supports. In the first step, zeolite A nano‐cubes with ∼350‐nm edges are prepared as a native impurity phase in zeolite Y synthesis dispersions, the support surface is pre‐modified with a cationic polymer having a selective affinity for zeolite A. The thus‐treated support is contacted with a colloidally stable dispersion of zeolite A and Y mixture in water, which results in selective, dense‐packed deposition of the zeolite A cubes with one face aligned to the average support surface. In a second step of hydrothermal epitaxial growth, the seed layer grows epitaxially into a continuous, meso‐defect free, ∼1 µm thick zeolite A layer, already after 1 h of treatment. This microstructure of the membrane compares very favorably to what is commonly obtained. The pH value of the zeolite mixture suspension is found to have a major influence on seed layer morphology, and thereby, on the quality and orientation of zeolite A membrane after short synthesis times. The final zeolite A membrane thickness and morphology is controlled by varying secondary growth synthesis time. The approach presented is thought to be of generic use for the preparation of oriented zeolite membranes.
Crystallinity‐Controlled Germanium Nanowire Arrays: Potential Field Emitters
Authors: Li Liang , Fang Xiaosheng , Chew Han Guan , Zheng Fei , Liew Tze Haw , Xu Xijin , Zhang Yunxia , Pan Shusheng , Li Guanghai , Zhang Lide 
Published: March 2008

AbstractWe report a simple method, oblique angle deposition, to directly synthesize aligned Ge nanowire arrays on a Si substrate. This process is accomplished by tilting the Si substrate and adjusting the incident angle of the evaporated Ge vapor flux with respect to the substrate normal to 87°. The resultant crystallinity of the Ge nanostructures can be tuned to either amorphous or poly‐ and single‐crystalline, depending on the substrate temperature and evaporation rate. The effects of thermal treatment on the morphology and structure of the Ge nanowires are discussed in detail. The field‐emission measurements show that increasing the annealing temperatures to about 550 °C results in a gradual increase in the maximum current density and a decrease in the turn‐on voltage, because of the decreased wire density originating from melting of the Ge nanowires. The field‐enhancement factor analysis shows there is an optimum range for Ge wire density and aspect ratio to obtain good emission performance. Ge nanowire arrays might find potential application in the field emitters of the future.
Biologically Inspired Surfaces: Broadening the Scope of Roughness**
Authors: Nosonovsky Michael , Bhushan Bharat 
Published: March 2008

AbstractSuperhydrophobicity can be used for many applications that require non‐adhesive and water‐repellent surfaces. A successful design of superhydrophobic surfaces requires a correct assessment of the surface roughness effect on wetting. Roughness is an important property in surface mechanics, physics, chemistry, and biology, and it is critical for many tribological applications. Roughness can be defined in different ways, and the definition should be adequate to the problem under investigation. Our recent studies of biological and biomimetic superhydrophobic surfaces show that traditional roughness parameters, such as the root‐mean‐square, correlation length, or fractal dimension, are not always appropriate for the analysis of wetting. This is, in particular, due to the hierarchical nature of wetting mechanisms and interfaces. We discuss the effect of roughness on wetting mechanisms and relevant roughness parameters and ways to broaden the concept and scope of surface roughness.
Enantioselective Transfer Hydrogenation of Aliphatic Ketones Catalyzed by Ruthenium Complexes Linked to the Secondary Face of β‐Cyclodextrin
Authors: Schlatter Alain , Woggon Wolf‐D. 
Published: March 2008

AbstractRuthenium‐η‐arene complexes attached to the secondary face of β‐cyclodextrin catalyze the enantioselective reduction (ee up to 98%) of aliphatic and aromatic ketones in aqueous medium in the presence of sodium formate (HCOONa).
Ectocranial suture closure in Pan troglodytes and Gorilla gorilla: Pattern and phylogeny
Authors: Cray James , Meindl Richard S. , Sherwood Chet C. , Lovejoy C. Owen 
Published: March 2008

AbstractThe order in which ectocranial sutures undergo fusion displays species‐specific variation among primates. However, the precise relationship between suture closure and phylogenetic affinities is poorly understood. In this study, we used Guttman Scaling to determine if the modal progression of suture closure differs among Homo sapiens, Pan troglodytes, and Gorilla gorilla. Because DNA sequence homologies strongly suggest that P. troglodytes and Homo sapiens share a more recent common ancestor than either does with G. gorilla, we hypothesized that this phylogenetic relationship would be reflected in the suture closure patterns of these three taxa. Results indicated that while all three species do share a similar lateral‐anterior closure pattern, G. gorilla exhibits a unique vault pattern, which, unlike humans and P. troglodytes, follows a strong posterior‐to‐anterior gradient. P. troglodytes is therefore more like Homo sapiens in suture synostosis. Am J Phys Anthropol, 2008. © 2008 Wiley‐Liss, Inc.
Insights from the inside: Histological analysis of abnormal enamel microstructure associated with hypoplastic enamel defects in human teeth
Authors: Witzel C. , Kierdorf U. , Schultz M. , Kierdorf H. 
Published: March 2008

AbstractWe studied the abnormalities in enamel microstructure associated with enamel hypoplasia in human teeth from the early medieval (5th–7th century AD) cemetery of Barbing, Germany, using light and scanning electron microscopy. The main aim of the study was to test the hypothesis that by analyzing the microstructure of fully formed enamel it is possible to reconstruct the reaction pattern of secretory ameloblasts to stress events leading to enamel hypoplasia. From the histological findings, a sequence of increasing impairment of secretory ameloblast function involving three thresholds was deduced. Surpassing of each of these thresholds is assumed to result in characteristic changes in enamel microstructure attributable to specific functional/morphological alterations of secretory ameloblasts. Based on our results we propose a model identifying the principal factors influencing the reaction of secretory ameloblasts to stress. The present study demonstrates that by including microscopic analysis in the study of enamel hypoplasia, it is possible to obtain a more complete picture of the formation of these developmental defects than is possible by inspection of crown surface features alone, and to draw more substantiated conclusions about the possible nature of developmental defects of enamel. Am J Phys Anthropol, 2008. © 2008 Wiley‐Liss, Inc.
The bipedalism of the Dmanisi hominins: Pigeon‐toed early Homo?
Authors: Wallace Ian J. , Demes Brigitte , Jungers William L. , Alvero Martin , Su Anne 
Published: March 2008

AbstractIn the recent description of the hominin postcranial material from Dmanisi, Georgia, Lordkipanidze and colleagues (Lordkipanidze et al. [2007] Nature 449: 305–310) claim that the Dmanisi hominins walked with more medially oriented feet than do modern humans. They draw this functional inference from two postcranial features: a wide talar neck angle and a slight medial torsion of the tibia. However, we believe that the data provided by the authors fail to support their conclusions. Talar neck angle and tibial torsion values from the Dmanisi specimens fall comfortably within the range of modern human variation. We further submit that foot orientation cannot be reliably deduced from the tibia and talus alone. Am J Phys Anthropol, 2008. © 2008 Wiley‐Liss, Inc.
Kombinatorische Übergangsmetallkatalyse: Mischungen einzähniger Liganden zur Kontrolle der Enantio‐, Diastereo‐ und Regioselektivität
Authors: Reetz Manfred T. 
Published: March 2008

AbstractDer vorliegende Aufsatz befasst sich mit einem neuartigen Konzept der kombinatorischen homogenen Übergangsmetallkatalyse, das über die herkömmliche parallelisierte Synthese modularer Liganden hinausgeht. Dieses Konzept beruht auf dem Einsatz von Mischungen einzähniger Liganden La und Lb, die in Gegenwart von Übergangsmetallen (M) neben den beiden Homo‐Kombinationen [MLaLa] und [MLbLb] ebenfalls die Hetero‐Kombination [MLaLb] bilden. Ist die letztgenannte Hetero‐Kombination reaktiver und selektiver als die jeweiligen Homo‐Kombinationen, erhält man ein verbessertes Katalysatorsystem, ohne dass dabei neue Liganden synthetisiert werden müssen. Hierbei ist eine Kontrolle der Enantio‐, Diastereo‐ und Regioselektivität möglich.
Effect of the axial vibration of screw on total shear strain distribution of melt in single‐screw extruders
Authors: Feng Yan‐Hong , Qu Jin‐Ping , He He‐Zhi , Liu Bin , Cao Xian‐Wu , Wen Sheng‐Ping 
Published: March 2008

AbstractSingle screw extruders are known as good melt pumps with the high, stable pressure needed for part extrusion. However they have a particular disadvantage in achieving good mixing. In a vibration‐induced polymer extruder (VIPE), a vibration force field (VFF) is introduced into the whole extrusion process by the axial vibration of screw, which affects the mixing process. It is well‐known that the total shear strain (TSS) has been widely used to measure the effect of melt mixing in a laminar system. In this study, an analytic model for pulsating TSS was developed and the TSS distribution of the melt in the screw channel of the melt conveying section in a VIPE was calculated to further understand the time‐dependent dynamic laminar mixing process. A comparison of the TSS distribution of melt in screw channel with and without vibration shows that the TSS of melt increases with the application of vibration and the larger the vibration frequency and amplitude are, the larger the TSS that the melt may experience while melt traveling through the melt conveying section, which is favorable for melt mixing. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Pharmacokinetics of dihydroartemisinin in Artekin tablets for single and repeated dosing in Chinese healthy volunteers
Authors: Hong Xin , Liu Chang‐hui , Huang Xiao‐tao , Huang Tian‐lai , Ye Shao‐mei , Ou Wei‐ping , Wang Ning‐sheng , Mi Sui‐qing 
Published: March 2008

AbstractAim. To study the pharmacokinetics of dihydroartemisinin (DHA) in Artekin (compound dihydroartemisinin) tablets in Chinese healthy volunteers. Methods. Eighteen healthy volunteers (9 males, 9 females) received Artekin tablets for oral administration. The plasma samples of DHA were analysed by liquid–liquid extraction and determined by HPLC/ESI/MS. Results. The plasma DHA concentration–time curves of single dose and repeated doses of DHA were fitted to a two‐compartment open model. The mean pharmacokinetic parameters of DHA in a single dose were: t1/2(β)=1.245 ± 0.495 h, Cmax=243.6 ± 56.15 µg/l, AUC0 → ∞=450 ± 69 h × µg/l, Vd=5.75 ± 2.2 l/kg and Cl=3.245 ± 0.38 l/h/kg, while in repeated doses they were: t1/2(β)=1.085 ± 0.298 h, AUC0 → ∞=444.35 ± 80.43 h × ng/ml, Vd=4.62 ± 1.128 ml/kg, Cl=3.0125 ± 0.875 ml/h/kg, respectively. Conclusion. The study showed that DHA in Artekin was rapidly absorbed, distributed and eliminated in the healthy subjects. The pharmacokinetic properties of DHA in Artekin were not affected by gender in a single dose. While in repeated doses accumulation of DHA did not appear after repeated doses. Copyright © 2008 John Wiley & Sons, Ltd.
Superiority of a new gradient system utilizing a critical threshold for the adsorption capacity of polypeptides to column packing when compared with a standard gradient system for the simultaneous and quantitative analysis of polypeptides
Authors: Goda Ryoya , Masumoto Hiroshi , Okazaki Osamu , Sudo Kenichi 
Published: March 2008

AbstractCompared with a standard gradient system, the new gradient system which we developed has a major advantage because it permits a wide range of acetonitrile content, e.g. more than the critical threshold, in the polypeptide solution and allows the quantitative analysis of the polypeptide with satisfactory analytical precision. Additionally, this new gradient system allows the enhancement of the sensitivity of the polypeptide analysis proportionate to the increased volume of solution loaded with the same levels of precision. In contrast, when using a standard gradient system it is difficult to analyze a polypeptide quantitatively with good precision due to either adsorption to various materials or to irregular change in the ratio between a retained and a passed peak of the polypeptide. Additionally, the appearance of a passed peak results in a loss in the sensitivity of the polypeptide analysis, although no adsorption of a polypeptide to various materials occurs in a solution with acetonitrile content more than the critical threshold. Consequently, the new gradient system is effective for the simultaneous and quantitative analysis of different polypeptides with good precision and without any loss of sensitivity due to either adsorption to various materials or the appearance of a passed peak. Copyright © 2008 John Wiley & Sons, Ltd.
Modeling of the Ultrafiltration of a Dextran T500 Solution in a Tubular Membrane Module
Authors: Chikhi M. , Meniai A.‐H. , Balaska F. , Bencheikh‐Lehocine M. 
Published: March 2008

AbstractMathematical modeling of an ultrafiltration membrane separation process, based mainly on the transmembrane pressure (TMP), is undertaken in the present work. The main objective is the prediction of the permeate flux of a solution containing Dextran T500 through a cylindrical module. The proposed model incorporates the resistance‐in‐series model coupled with the equation describing the solute (Dextran T500) transport, as well as the continuity and Navier‐Stokes equations for solution flow modeling. The model equations are solved using finite‐volume numerical methods, with appropriate initial and boundary conditions. The effects of the TMP and the length of the membrane on the mean permeate flux were also investigated. The influence of the membrane dimensions (aspect ratio) on the relative dimensionless mean permeate flux, at different inlet TMPs and different solution concentrations, respectively, have also been considered. The variations of the TMP with the membrane length as well as the influence of the Peclet number on the solute surface concentration were also examined. The numerical results obtained are compared with experimental values reported in the literature, and in general, the agreement is satisfactory enough to encourage further refinement of the model.
Estimating the Bubble Point Pressure and Formation Volume Factor of Oil Using Artificial Neural Networks
Authors: Rasouli H. , Rashidi F. , Ebrahimian A. 
Published: March 2008

AbstractThe phase performance of hydrocarbons is a very complicated behavior that hydrocarbons show at the time of phase change or when they remain in a particular phase. Process design is almost impossible without a good understanding of this behavior. Artificial Neural Networks have been widely utilized for engineering applications during the last two decades. Two models are presented for the prediction of the bubble point pressure and the oil formation volume factor for hydrocarbon mixtures using the Artificial Neural Networks (ANNs) approach. For this purpose, five‐layer neural networks were designed and trained using 106 experimental data points. After the training step, 9 experimental data points were also used for the model evaluation step and as a reliability check. The output of the models for both the training and predicted data are compared with the empirical equations of Standing, Glaso and Marhoun. It is concluded that the ANNs approach has an excellent capability for these purposes compared to the conventional methods.
Comparative Study of Flow Structure in Circulating Fluidized Bed Risers with FCC and Sand Particles
Authors: Qi X.‐B. , Huang W.‐X. , Zhu J. 
Published: March 2008

AbstractThe combined influences of particle properties and nozzle gas distributor design on the axial and radial flow structure in two 100 mm i.d., 15.1 m and 10.5 m long risers with FCC and sand particles were investigated by measuring the axial pressure gradient profiles, and the axial and radial profiles of solids concentration. The results show that the nozzle gas distributor design has significant effects on the axial and radial flow structure for the FCC and sand particles. At lower superficial gas velocity of less than 8.0 m/s, the upward gas‐solid flow of the sand particles decelerates in various degrees with the disappearing of the nozzle gas distributor effect. The upward gas‐solid flow of the FCC particles, however, occurs without noticeable deceleration within the range of this study. In the acceleration section, the radial distributions of the local solids concentration of the FCC particles are more uniform than those of sand particles under the same operating conditions; while in the fully developed zone, the sand particles have a more uniform radial distribution than the FCC particles. The gas‐solid flow is first developed in the center region, and then extends towards the wall. The overall flow development in the riser mainly depends on the local gas‐solid flow in the wall region.
Homoleptic Copper(I) Arylthiolates as a New Class of p‐Type Charge Carriers: Structures and Charge Mobility Studies
Authors: Che Chi‐Ming , Li Cheng‐Hui , Chui Stephen Sin‐Yin , Roy V. A. L. , Low Kam‐Hung 
Published: March 2008

AbstractPolymeric homoleptic copper(I) arylthiolates [Cu(p‐SC6H4‐X)]∞ (X=CH3 (1), H (2), CH3O (3), tBu (4), CF3 (5), NO2 (6), and COOH (7)) have been prepared as insoluble crystalline solids in good yields (75–95 %). Structure determinations by powder X‐ray diffraction analysis have revealed that 1–3 and 6 form polymers of infinite chain length, with the copper atoms bridged by arylthiolate ligands. Weak intra‐chain π⋅⋅⋅π stacking interactions are present in 1–3, as evidenced by the distances (3.210 Å in 1, 3.016 Å in 2, 3.401 Å in 3) between the mean planes of neighboring phenyl rings. In the structure of 6, the intra‐chain π⋅⋅⋅π interactions (d=3.711 Å) are insignificant and the chain polymers are associated through weak, non‐covalent CH⋅⋅⋅O hydrogen‐bonding interactions (d=2.586 Å). Samples of 1–7 in their polycrystalline forms proved to be thermally stable at 200–300 °C; their respective decomposition temperatures are around 100 °C higher than that of the aliphatic analogue [Cu(SCH3)]∞. Data from in situ variable‐temperature X‐ray diffractometry measurements indicated that the structures of both 1 and 7 are thermally more robust than that of [Cu(SCH3)]∞. TEM analysis revealed that the solid samples of 1–5 and [Cu(SCH3)]∞ contained homogeneously dispersed crystalline nanorods with widths of 20–250 nm, whereas smaller plate‐like nanocrystals were found for 6 and 7. SAED data showed that the chain polymers of 1–3 and [Cu(SCH3)]∞ similarly extend along the long axes of their nanorods. The nanorods of 1–5 and [Cu(SCH3)]∞ have been found to exhibit p‐type field‐effect transistor behavior, with charge mobility (μ) values of 10−2–10−5 cm2 V−1 s−1. Polycrystalline solid samples of 6 and 7 each showed a low charge mobility (<10−6 cm2 V−1 s−1). The charge mobility values of field‐effect transistors made from crystalline nanorods of 1–3 and [Cu(SCH3)]∞ could be correlated with their unique chain‐like copper–sulfur networks, with the para‐substituent of the arylthiolate ligand influencing the charge‐transport properties.
ChemInform Abstract: Doping the Golden Cage Au16‐ with Si, Ge, and Sn.
Authors: Wang Lei‐Ming , Bulusu Satya , Huang Wei , Pal Rhitankar , Wang Lai‐Sheng , Zeng Xiao Cheng 
Published: March 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Enhanced Thermoelectric Performance of Rough Silicon Nanowires.
Authors: Hochbaum Allon I. , Chen Renkun , Delgado Raul Diaz , Liang Wenjie , Garnett Erik C. , Najarian Mark , Majumdar Arun , Yang Peidong 
Published: March 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Silicon Nanowires as Efficient Thermoelectric Materials.
Authors: Boukai Akram I. , Bunimovich Yuri , Tahir‐Kheli Jamil , Yu Jen‐Kan , Goddard William A. III , Heath James R. 
Published: March 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Phase Transitions in Cd3P2 at High Pressures and High Temperatures.
Authors: Yel'kin F. S. , Sidorov V. A. , Waskowska A. , Gerward L. , Olsen J. Staun , Vaitheeswaran G. , Kanchana V. 
Published: March 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Crystal Structures of the Ln5CoSb2 Ternary Phases (Ln: Gd, Tb, Dy, Ho, Er).
Authors: Verbovytsky Yu. , Latka K. 
Published: March 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Cationic P(OPh)3‐ or PPh3‐Rhodium(I) Complex‐Catalyzed Isomerizations of 5‐Alkynals to δ‐Alkynyl Ketones, Cyclopent‐1‐enyl Ketones, and Cyclohexenones.
Authors: Tanaka Ken , Sasaki Kaori , Takeishi Kenzo , Hirano Masao 
Published: March 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Highly Selective anti‐Markovnikov Addition of Thiols to Vinyl Ethers under Solvent‐ and Catalyst‐Free Conditions.
Authors: Lou Feng‐Wen , Xu Jian‐Ming , Liu Bo‐Kai , Wu Qi , Pan Qian , Lin Xian‐Fu 
Published: March 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.