bluuebunny/crossref_metadata_2025_split huggingface dataset:
A processing method enabling the use of peak height for accurate and precise proton NMR quantitation
Authors: Hays Patrick A. , Thompson Robert A. 
Published: June 2009

AbstractIn NMR, peak area quantitation is the most common method used because the area under a peak or peak group is proportional to the number of nuclei at those frequencies. Peak height quantitation has not enjoyed as much utility because of poor precision and linearity as a result of inconsistent shapes and peak widths (measured at half height). By using a post‐acquisition processing method employing a Gaussian or line‐broadening (exponential decay) apodization (i.e. weighting function) to normalize the shape and width of the internal standard (ISTD) peak, the heights of an analyte calibration spectrum can be compared to the analyte peaks in a sample spectrum resulting in accurate and precise quantitative results. Peak height results compared favorably with ‘clean’ peak area results for several hundred illicit samples of methamphetamine HCl, cocaine HCl, and heroin HCl, of varying composition and purity. Using peak height and peak area results together can enhance the confidence in the reported purity value; a major advantage in high throughput, automated quantitative analyses. Published in 2009 by John Wiley & Sons, Ltd.
An enhanced constitutive model for crushable granular materials
Authors: Daouadji Ali , Hicher Pierre‐Yves 
Published: June 2009

AbstractStudies in the past have tried to reproduce the mechanical behaviour of granular materials by proposing constitutive relations based on a common assumption that model parameters and parameters describing the properties, including gradation of individual grains are inevitably linked. However successful these models have proved to be, they cannot account for the changes in granular assembly behaviour if the grains start to break during mechanical loading. This paper proposes to analyse the relation between grading change and the mechanical behaviour of granular assembly. A way to model the influence of grain breakage is to use a critical state‐based model. The influence of the amount of grain breakage during loading, depending on the individual grain strength and size distribution, can be introduced into constitutive relations by means of a new parameter that controls the evolution of critical state with changes in grain size distribution. Experimental data from a calcareous sand, a quartz sand, and a rockfill material were compared with numerical results and good‐quality simulations were obtained. The main consequences of grain breakage are increased compressibility and a gradual dilatancy disappearance in the granular material. The critical state concept is also enriched by considering its overall relation to the evolution of the granular material. Copyright © 2009 John Wiley & Sons, Ltd.
On the determination of a set of material constants for a high‐cycle accumulation model for non‐cohesive soils
Authors: Wichtmann T. , Niemunis A. , Triantafyllidis Theodor 
Published: June 2009

AbstractThe paper discusses the determination of a set of constants for the high‐cycle accumulation model (HCA) proposed by the authors. The HCA model predicts permanent strains or excess pore water pressures in non‐cohesive soils due to a cyclic loading with a large number of cycles and with small to intermediate strain amplitudes. The laboratory tests necessary for the determination of the material constants and their analysis are explained in detail in this paper. Copyright © 2009 John Wiley & Sons, Ltd.
Optimizing fishbone aisles for dual‐command operations in a warehouse
Authors: Pohl Letitia M. , Meller Russell D. , Gue Kevin R. 
Published: June 2009

AbstractUnit‐load warehouses store and retrieve unit‐loads, typically pallets. When storage and retrieval operations are not coordinated, travel is from a pickup and deposit (P&D) point to a pallet location and back again. In some facilities, workers interleave storage and retrieval operations to form a dual‐command cycle. Two new aisle designs proposed by Gue and Meller (“Improving the unit‐load warehouse.” In Progress in Material Handling Research: 2006. Material Handling Industry of America, Charlotte, NC, 2006) use diagonal aisles to reduce the travel distance to a single pallet location by approximately 10 and 20[percnt] for the two designs, respectively. We develop analytical expressions for travel between pallet locations for one of these—the fishbone design. We then compare fishbone warehouses that have been optimized for dual‐command to traditional warehouses that have been optimized in the same manner, and show that an optimal fishbone design reduces dual‐command travel by 10–15%. © 2009 Wiley Periodicals, Inc. Naval Research Logistics 54: 389–403, 2009
Unsteady MHD flow due to noncoaxial rotations of micropolar fluid and an accelerated disk with partial slip condition
Authors: Shahzad F. , Hayat T. , Ayub M. , Asghar S. 
Published: June 2009

AbstractAn analysis is carried out to study the magnetohydrodynamic (MHD) flow of an incompressible micropolar fluid. The flow is induced by the noncoaxial rotations of constantly accelerated porous disk and a micropolar fluid. The influence of partial slip on the flow has been taken into consideration. Numerical solution of the governing flow problem is given by means of Newto's method. The important finding in this communication is the effects of partial slip on the velocity and microrotation vector. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2010
On comparison of series and numerical solutions for second Painlevé equation
Authors: Ellahi R. , Abbasbandy S. , Hayat T. , Zeeshan A. 
Published: June 2009

AbstractThis attempt presents the series solution of second Painlevé equation by homotopy analysis method (HAM). Comparison of HAM solution is provided with that of the Adomian decomposition method (ADM), homotopy perturbation method (HPM), analytic continuation method, and Legendre Tau method. It is revealed that there is very good agreement between the analytic continuation and HAM solutions when compared with ADM, HPM, and Legendre Tau solutions. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2010
2D internal flux compatibility equation of the flux Green element method for transient nonlinear potential problems
Authors: Taigbenu Akpofure E. 
Published: June 2009

AbstractThis article presents the derivation and implementation of the normal directional flux compatibility equation (relationship) at internal nodes when the Green element formulation that consistently provides accurate estimates of the primary variable, and its normal directional derivative (normal flux) is applied in 2D heterogeneous media to steady and transient potential problems. Such a relationship is required to resolve the closure problem due to having fewer integral equations than the number of unknowns at internal nodes. The derivation of the relationship is based on Stokes' theorem, which transforms the contour integral of the normal directional fluxes into a surface integral that is identically zero. The numerical discretization of the compatibility equation is demonstrated with four numerical examples using the six‐node quadratic triangular and the four and eight‐node rectangular elements. The incorporation of triangular elements into the current formulation demonstrates that the internal compatibility equation can be successfully implemented on irregular grids. The direct calculation of the fluxes significantly enhances the accuracy of the formulation, so that high accuracy, exceeding that of the finite element method, is achieved with very coarse spatial discretization. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2010
Preparation and characterization of a composite PDMS membrane on CA support
Authors: Sadrzadeh Mohtada , Saljoughi Ehsan , Shahidi Kazem , Mohammadi Toraj 
Published: June 2009

AbstractPolydimethylsiloxane (PDMS) is the most commonly used membrane material for the separation of condensable vapors from lighter gases. In this study, a composite PDMS membrane was prepared and its gas permeation properties were investigated at various upstream pressures. A microporous cellulose acetate (CA) support was initially prepared and characterized. Then, PDMS solution, containing crosslinker and catalyst, was cast over the support. Sorption and permeation of C3H8, CO2, CH4, and H2 in the prepared composite membrane were measured. Using sorption and permeation data of gases, diffusion coefficients were calculated based on solution‐diffusion mechanism. Similar to other rubbery membranes, the prepared PDMS membrane advantageously exhibited less resistance to permeation of heavier gases, such as C3H8, compared to the lighter ones, such as CO2, CH4, and H2. This result was attributed to the very high solubility of larger gas molecules in the hydrocarbon‐based PDMS membrane in spite of their lower diffusion coefficients relative to smaller molecules. Increasing feed pressure increased permeability, solubility, and diffusion coefficients of the heavier gases while decreased those of the lighter ones. At constant temperature (25°C), empirical linear relations were proposed for permeability, solubility, and diffusion coefficients as a function of transmembrane pressure. C3H8/gas solubility, diffusivity, and overall selectivities were found to increase with increasing feed pressure. Ideal selectivity values of 9, 30, and 82 for C3H8 over CO2, CH4, and H2, respectively, at an upstream pressure of 8 atm, confirmed the outstanding separation performance of the prepared membrane. Copyright © 2009 John Wiley & Sons, Ltd.
Studies on UV‐stability of poly(MMA‐co‐M12‐co‐BPMA)/TiO2composite particles prepared by ultrasonically initiated emulsion polymerization
Authors: Zou Jiangpeng , Jiang Long , Nguyen Thien Phap , Dan Yi 
Published: June 2009

AbstractIn this paper, poly(methyl methacrylate‐co‐sodium sulfopropyl lauryl maleate‐co‐2‐hydroxy‐4‐(3‐methacryloxy‐2‐hydroxylpropoxy) benzophenone)/TiO2 (i.e., poly(MMA‐co‐M12‐co‐BPMA)/TiO2) composite particles were prepared by ultrasonically initiated emulsion polymerization. To study the dispersion and UV‐stability of the composite particles, laser diffraction particle size analyzer (LDPSA), ultraviolet‐visible absorption spectroscopy (UV‐vis), UV‐vis diffuse reflectance spectroscopy (DRS), differential scanning calorimeter (DSC), and the weight loss measurement were used. The results indicate that the dispersion of the poly(MMA‐co‐M12‐co‐BPMA)/TiO2 composite particles prepared by ultrasonically initiated emulsion polymerization is good. And the composite particles can absorb UV light; the ultraviolet absorption strength of poly(MMA‐co‐M12‐co‐BPMA) grafted onto the surface of TiO2 has not changed after UV irradiation while that of PMMA changed significantly. The UV absorption strength, weight loss, and Tg changes are in the order PMMA> poly(MMA‐co‐M12‐co‐BPMA) >PMMA grafted onto TiO2> poly(MMA‐co‐M12‐co‐BPMA) grafted onto TiO2. These results show that the ultrasonically initiated emulsion polymerization will enhance the UV stability of composite particles, and the UV‐stability of PMMA can be enhanced by the introduction of the organic UV‐stabilizer BPMA and the inorganic UV‐stabilizer titanium dioxide into the PMMA chains by covalent bond, and the effect of the BPMA and the TiO2 used together is better than that used, respectively. Copyright © 2009 John Wiley & Sons, Ltd.
pH‐induced on–off switching of polycarbonate track‐etched membranes by plasma‐induced surface grafting
Authors: Li Chunyan , Cao Bing , Wang Wencai , Li Qifang , Zhao Jing , Zhang Liqun 
Published: June 2009

AbstractSurface functionalization of the plasma‐pretreated polycarbonate (PC) track‐etched membranes via plasma‐induced thermally graft copolymerization of acrylic acid (AAc) was carried out. The resulting PC membranes with grafted AAc side chains were characterized by X‐ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric (TG) analysis. The morphology of the PC membranes was studied by scanning electron microscopy (SEM). The results showed that the grafted PAAc polymers were formed uniformly inside the pores throughout the entire membrane thickness. With increase in the pore‐filling ratio, the pore diameters of PAAc‐grafted membranes became smaller. The PC‐g‐PAAc membranes exhibit rapid and reversible response of the flux to the environmental pH as pH is switched between 3 and 9. Between pH 3.5 and 5.5, the membranes demonstrate a pH‐valve function as the carboxyl group changes from neutral to charged with a corresponding variation in chain configuration. Copyright © 2009 John Wiley & Sons, Ltd.
Antioxidant and spectroscopic studies of crosslinked polymers synthesized by grafting polymerization of ferulic acid
Authors: Parisi Ortensia Ilaria , Puoci Francesco , Iemma Francesca , De Luca Giuseppina , Curcio Manuela , Cirillo Giuseppe , Spizzirri Umile Gianfranco , Picci Nevio 
Published: June 2009

AbstractA novel, simple synthetic strategy for the preparation of crosslinked polymers with significant antioxidant properties is proposed. Ferulic acid (FA), a well‐known antioxidant compound, due to its reactivity toward free radical process, was inserted into a polymeric network with methacrylic acid (MAA) and ethylene glycole dimethacrylate acting as comonomer and crosslinker, respectively. All the reactants were simultaneously mixed in the polymerization feed and one‐pot radical reaction was carried out. Irregular microparticles were prepared by bulk polymerization and microspheres by precipitation polymerization. The materials were characterized by nuclear magnetic resonance–magic angle spinning (NMR‐MAS) studies, to verify effective FA insertion into polymeric networks, and by morphological, dimensional analyses, and water absorption measurement to study their superficial and swelling properties, respectively. Antioxidant properties of materials were evaluated by linoleic acid emulsion system–thiocyanate assay, determination of scavenging activity on DPPH radicals, determination of available phenolic groups in polymeric matrices, and determination of total antioxidant capacity. Copyright © 2009 John Wiley & Sons, Ltd.
Comparison of CpG island hypermethylation and repetitive DNA hypomethylation in premalignant stages of gastric cancer, stratified for Helicobacter pylori infection
Authors: Park Seog‐Yun , Yoo Eun J , Cho Nam‐Yun , Kim Nayoung , Kang Gyeong H 
Published: June 2009

AbstractCpG island hypermethylation and genomic DNA hypomethylation are found not only in gastric cancers but also in associated premalignant lesions. Helicobacter pylori infection induces aberrant CpG island hypermethylation in gastric mucosae. However, little is known about the relationship between H. pylori infection and aberrant methylation in premalignant lesions. The present study characterized methylation changes in a subset of genes and repetitive DNA elements (ALU, LINE‐1, SAT2) and examined their relationship with H. pylori infection in premalignant lesions of gastric cancers. We performed MethyLight analysis of 25 genes and SAT2 and COBRA analysis of ALU and LINE‐1 in 212 gastric tissue samples. H. pylori infection was closely associated with enhanced hypermethylation of CpG island loci in chronic gastritis samples, but this association was not found among intestinal metaplasias, gastric adenomas and gastric cancers. The number of methylated genes was greater in intestinal metaplasia and gastric adenoma samples than in chronic gastritis samples, regardless of H. pylori infection. Methylation of repetitive DNA elements in gastric lesions generally decreased with progression of the gastric lesion along the multistep carcinogenesis. No difference was noted in the number of methylated genes in chronic gastritis or intestinal metaplasia between gastric cancer patients and non‐cancer subjects. In conclusion, we found that there was no enhanced CpG island hypermethylation in gastric cancer and premalignant lesions in association with H. pylori infection and our findings suggest that CpG island hypermethylation and repetitive DNA hypomethylation are enhanced with progression of the gastric lesion through the multistep carcinogenesis, regardless of the status of H. pylori infection. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Commentary: The federal ‘Prenatally and Postnatally Diagnosed Conditions Awareness Act’
Authors: Reilly Philip R. 
Published: June 2009

AbstractThe recently enacted federal law, the ‘Prenatally and Postnatally Diagnosed Conditions Awareness Act’ (United States Public Law 110–374) seeks to improve opportunities for parents and pregnant women to anticipate and understand the likely life course of children born with Down syndrome and other (unspecified) conditions. The law is in part a response to the continued growth of prenatal screening and testing. For example, the American College of Obstetricians and Gynecologists' Practice Bulletin 77 recommends that ‘Screening and invasive diagnostic testing for aneuploidies be available to all women who present for prenatal care before 20 weeks of gestation regardless of maternal age.’ Emerging technologies anticipate an era in which the scope of prenatal screening and testing will be much larger than it is today. Inevitably, more women will find themselves facing the hard question of whether to continue or end a pregnancy in which a fetus has been found to have a significant abnormality. While the new federal law is not likely to have a major impact on obstetric practice, it may be a harbinger of renewed wide‐scale public debate concerning the ethics of prenatal screening. Copyright © 2009 John Wiley & Sons, Ltd.
A designed chimeric cyanovirin‐N homolog lectin: Structure and molecular basis of sucrose binding
Authors: Koharudin Leonardus M. I. , Furey William , Gronenborn Angela M. 
Published: June 2009

AbstractThe NMR and X‐ray structures of a designed chimeric cyanovirin‐N homolog (CVNH) protein were determined. The individual halves of the structure are similar to their counterparts in the parent proteins, with domains A and B resembling the structures of TbCVNH and NcCVNH, respectively. No significant differences between the solution and crystal conformations were observed, although details in loop conformations and distinct crystal packing‐induced features are present. Carbohydrate binding studies by NMR revealed affinity and specificity for Glcα(1‐2)Frc and Manα(1‐2)Man, and the parental half that is devoid of any sucrose affinity in NcCVNH was transformed into a genuine sucrose binding site in the context of the chimera. The atomic details of sugar recognition are seen in the crystal structure of the protein with two bound Glcα(1‐2)Frc molecules. Both sugars exhibit different conformations around the glycosidic bond and engage in unique hydrogen bonding networks in the two sites. Although the protein is able to bind two Manα(1‐2)Man molecules, a property associated with HIV‐inactivation, no anti‐HIV activity was observed for the hybrid protein. These results provide the structural basis for sugar recognition in the CVNH family and aid in deciphering the relationship between sugar binding and anti‐HIV activity. Proteins 2009. © 2009 Wiley‐Liss, Inc.
Fundamental absorption edge and near‐absorption edge properties of PLZT thin films
Authors: Khodorov A. , Gomes M. J. M. 
Published: June 2009

AbstractLanthanum‐doped lead zirconate titanate (PLZT) thin films were fabricated by sol–gel, as well as, pulsed‐laser deposition methods on sapphire (0001) and MgO (100) substrates, respectively. The cell parameters of the films were calculated with the help of a whole‐pattern fitting procedure. The study of their optical properties revealed the fractal behavior of the absorption coefficient near the absorption edge (Eg). For laser‐ablated and sol–gel‐derived films, Eg was estimated to be 3.61 and 3.65 eV, respectively. This shift of Eg was suggested to relate to a difference in strain values and the volume‐deformation potential was estimated to be −2.4 eV. The strong shift of Eg in the thin films in comparison to bulk PLZT was also observed. This shift could not only be attributed to the presence of strain, but could also be due to increased disorder and polarization fluctuations.
In situ analysis of optoelectronic properties of dislocations in ZnO in TEM observations
Authors: Ohno Yutaka , Taishi Toshinori , Yonenaga Ichiro 
Published: June 2009

AbstractExtended defects acting as non‐radiative recombination center or those acting as radiative one were, respectively, studied by transmission electron microscopy under the illumination of a monochromatic light or cathodoluminescence spectroscopy combined with light illumination. By means of this method, defect levels associated with dislocations in ZnO, which were introduced at elevated temperatures above 923 K, were determined. It was proposed that (i) a screw dislocation, presumably acting as non‐radiative recombination center, glides under the illumination of a light with photon energy above 2.48–2.61 eV, due to an electron–hole recombination at a defect level of 2.48–2.61 eV depth, and (ii) a mixed dislocation acts as radiative recombination center with a defect level of 3.1 eV depth.
Helium implantation into 4H‐SiC
Authors: Barbot Jean François , Leclerc Stéphanie , David Marie‐Laure , Oliviero Erwan , Montsouka Romaric , Pailloux Frederic , Eyidi Dominique , Denanot Marie‐Françoise , Beaufort Marie‐France , Declémy Alain , Audurier Valérie , Tromas Christophe 
Published: June 2009

AbstractThe paper provides the properties of single crystalline 4H‐SiC under helium implantation at temperatures of implantation up to 750 °C and fluences in the range 5 × 1015–1 × 1017 cm−2. The microstructure evolution was studied by transmission electron microscopy cross‐section and X‐ray diffraction experiments. The mechanical property changes were investigated by using nanoindentation tests followed by atomic force microscopy observations and by using tribological tests. At elevated temperature of implantation and/or in the low fluence regime at room temperature where only the strained state of SiC is obtained, SiC becomes more resistant to crack formation but no significant change in mechanical properties is seen. At room temperature with increasing fluence the damage accumulation leads to the amorphous state for which a strong degradation of the mechanical properties is observed. At elevated temperature of implantation, amorphization is avoided and a thermally activated saturation of the strain is observed in the near surface region whereas defect accumulation occurs near the maximum of damage. Upon annealing subsequent to room temperature implantation, the near surface strain progressively relaxes while the helium ions agglomerate into platelets around the maximum of strain. These platelets evolve into bubble clusters at temperatures where the vacancies become mobile. Under particular conditions of implantation (high fluence and elevated temperature) the swelling of the surface increases during annealing due to the growth of bubbles and the formation of stacking faults resulting from the migration of interstitials towards the maximum of damage.
Bragg–(Bragg)m–Laue diffraction and its interference fringe
Authors: Hirano Kenji , Fukamachi Tomoe , Yoshizawa Masami , Negishi Riichirou , Hirano Keiichi , Kawamura Takaaki 
Published: June 2009

AbstractX‐Ray rocking curves from side surface of a thin plane‐parallel Ge crystal are measured under the condition where the dispersion of the refracted angle is quite large. In the diffracted beams from side surface are observed, which are analysed by using Wagner's approach for Bragg–(Bragg)m–Laue case. The origin of the fringes is explained by the interference between diffraction beams in Bragg–Laue case and that in Bragg–Bragg–Laue case.