bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of the slow crack growth susceptibility coefficient of dental ceramics using different methods
Authors: Gonzaga Carla Castiglia , Cesar Paulo Francisco , Miranda Walter Gomes , Yoshimura Humberto Naoyuki 
Published: June 2011

AbstractThis study compared three methods for the determination of the slow crack growth susceptibility coefficient (n) of two veneering ceramics (VM7 and d.Sign), two glass‐ceramics (Empress and Empress 2) and a glass‐infiltrated alumina composite (In‐Ceram Alumina). Discs (n = 10) were prepared according to manufacturers' recommendations and polished. The constant stress‐rate test was performed at five constant stress rates to calculate nd. For the indentation fracture test to determine nIF, Vickers indentations were performed and the crack lengths were measured under an optical microscope. For the constant stress test (performed only for d.Sign for the determination of ns) four constant stresses were applied and held constant until the specimens' fracture and the time to failure was recorded. All tests were performed in artificial saliva at 37°C. The nd values were 17.2 for Empress 2, followed by d.Sign (20.5), VM7 (26.5), Empress (30.2), and In‐Ceram Alumina (31.1). In‐Ceram Alumina and Empress 2 showed the highest nIF values, 66.0 and 40.2, respectively. The nIF values determined for Empress (25.2), d.Sign (25.6), and VM7 (20.1) were similar. The ns value determined for d.Sign was 31.4. It can be concluded that the n values determined for the dental ceramics evaluated were significantly influenced by the test method used. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Induction plasma sprayed Sr and Mg doped nano hydroxyapatite coatings on Ti for bone implant
Authors: Roy Mangal , Bandyopadhyay Amit , Bose Susmita 
Published: June 2011

AbstractIn this study, we report fabrication of strontium (Sr) and magnesium (Mg) doped hydroxyapatite (HA) coating on commercially pure titanium (Cp‐Ti) substrates using inductively coupled radio frequency (RF) plasma spray. HA powder was doped with 1 wt % Sr (Sr‐HA) and 1 wt % Mg (Mg‐HA), heat treated at 800°C for 6 h and then used for plasma spray coating. X‐ray diffraction (XRD) and Fourier transformed infrared spectroscopic (FTIR) analysis indicated that the coatings were primarily composed of phase pure crystalline HA. When compared to undoped HA coating, physical properties such as microstructure, grain size, and adhesive bond strength of the doped HA coatings did not change significantly. Microstructure of the coatings showed coherency in the structure with an average grain size of 200–280 μm HA particles, where each of the HA grains consisted of 20–30 nm sized particles. An average adhesive bond strength of 17 MPa ensured sufficient mechanical strength of the coatings. A chemistry dependent improvement in bone cell‐coating interaction was noticed for doped coatings although it had minimal effect on physical properties of the coatings. In vitro cell–materials interactions using human fetal osteoblasts (hFOB) showed better cell attachment and proliferation on Sr‐HA coatings compared to HA or Mg‐HA coatings. Presence of Sr in the coating also stimulated hFOB cell differentiation and alkaline phosphatase (ALP) expression. Improvement in bioactivity of Sr doped HA coatings on Ti without compromising its mechanical properties makes it an excellent material of choice for coated implant. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Serum 25-hydroxyvitamin D and clinical fracture risk in a multiethnic cohort of women: The women's health initiative (WHI)
Authors: Cauley Jane A , Danielson Michelle E , Boudreau Robert , Barbour Kamil E , Horwitz Mara J , Bauer Douglas C , Ensrud Kristine E , Manson JoAnn E , Wactawski-Wende Jean , Shikany James M , Jackson Rebecca D 
Published: June 2011

Abstract
Low 25-hydroxyvitamin D [25(OH)D] levels have been linked to hip fracture in white women. To study the association of 25(OH)D with risk of fracture in multiethnic women, we performed a nested case-control study within the prospective Women's Health Initiative (WHI) Observational Study. Incident fractures were identified in 381 black, 192 Hispanic, 113 Asian, and 46 Native American women over an average of 8.6 years. A random sample of 400 white women who fractured was chosen. One control individual was selected per case and matched on age, race/ethnicity, and blood draw date. 25(OH)D, parathyroid hormone, and vitamin D–binding protein (DBP) were measured in fasting baseline serum. Conditional logistic regression models were used to calculate the odds ratio (OR) and 95% CI. In multivariable models, higher 25(OH)D levels compared with levels less than 20 ng/mL were associated with a lower risk of fracture in white women (20 to &lt;30 ng/mL: OR = 0.82, 95% CI 0.58–1.16; ≤30.0 ng/mL: OR = 0.56, 95% CI 0.35–0.90; p trend = 0.02). In contrast, higher 25(OH)D (≥20 ng/mL) compared with levels less than 20 ng/mL were associated with a higher risk of fracture in black women (OR = 1.45, 95% CI 1.06–1.98; p trend = 0.043). Higher 25(OH)D (≥30.0 ng/mL) was associated with higher fracture risk in Asian women after adjusting for DBP (OR = 2.78, 95% CI 0.99–7.80; p trend = 0.04). There was no association between 25(OH)D and fracture in Hispanic or Native American women. Our results suggest divergent associations between 25(OH)D and fracture by race/ethnicity. The optimal level of 25(OH)D for skeletal health may differ in white and black women. © 2011 American Society for Bone and Mineral Research
Intermittent PTH(1–84) is osteoanabolic but not osteoangiogenic and relocates bone marrow blood vessels closer to bone-forming sites
Authors: Prisby Rhonda , Guignandon Alain , Vanden-Bossche Arnaud , Mac-Way Fabrice , Linossier Marie-Thérèse , Thomas Mireille , Laroche Norbert , Malaval Luc , Langer Max , Peter Zoltz-Andrei , Peyrin Françoise , Vico Laurence , Lafage-Proust Marie-Hélène 
Published: June 2011

Abstract
Intermittent parathyroid hormone (PTH) is anabolic for bone. Our aims were to determine (1) whether PTH stimulates bone angiogenesis and (2) whether vascular endothelial growth factor (VEGF A) mediates PTH-induced bone accrual. Male Wistar rats were given PTH(1–84) daily, and trabecular bone mass increased 150% and 92% after 30 and 15 days, respectively. The vascular system was contrasted to image and quantify bone vessels with synchrotron radiation microtomography and histology. Surprisingly, bone vessel number was reduced by approximately 25% and approximately 40% on days 30 and 15, respectively. PTH redistributed the smaller vessels closer to bone-formation sites. VEGF A mRNA expression in bone was increased 2 and 6 hours after a single dose of PTH and returned to baseline by 24 hours. Moreover, anti-VEGF antibody administration (1) blunted the PTH-induced increase in bone mass and remodeling parameters, (2) prevented the relocation of bone vessels closer to bone-forming sites, and (3) inhibited the PTH-induced increase in mRNA of neuropilin 1 and 2, two VEGF coreceptors associated with vascular development and function. In conclusion, PTH(1–84) is osteoanabolic through VEGF-related mechanism(s). Further, PTH spatially relocates blood vessels closer to sites of new bone formation, which may provide a microenvironment favorable for growth. © 2011 American Society for Bone and Mineral Research
Molecular modeling study of checkpoint kinase 1 inhibitors by multiple docking strategies and prime/MM–GBSA calculation
Authors: Du Juan , Sun Huijun , Xi Lili , Li Jiazhong , Yang Ying , Liu Huanxiang , Yao Xiaojun 
Published: June 2011

AbstractDeveloping chemicals that inhibit checkpoint kinase 1 (Chk1) is a promising adjuvant therapeutic to improve the efficacy and selectivity of DNA‐targeting agents. Reliable prediction of binding‐free energy and binding affinity of Chk1 inhibitors can provide a guide for rational drug design. In this study, multiple docking strategies and Prime/Molecular Mechanics Generalized Born Surface Area (Prime/MM‐GBSA) calculation were applied to predict the binding mode and free energy for a series of benzoisoquinolinones as Chk1 inhibitors. Reliable docking results were obtained using induced‐fit docking and quantum mechanics/molecular mechanics (QM/MM) docking, which showed superior performance on both ligand binding pose and docking score accuracy to the rigid‐receptor docking. Then, the Prime/MM–GBSA method based on the docking complex was used to predict the binding‐free energy. The combined use of QM/MM docking and Prime/MM–GBSA method could give a high correlation between the predicted binding‐free energy and experimentally determined pIC50. The molecular docking combined with Prime/MM–GBSA simulation can not only be used to rapidly and accurately predict the binding‐free energy of novel Chk1 inhibitors but also provide a novel strategy for lead discovery and optimization targeting Chk1. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
The effect of polarization on multiple hydrogen‐bond formation in models of self‐assembling materials
Authors: Chen Yung‐Fou , Dannenberg J. J. 
Published: June 2011

AbstractWe report density functional theory calculations at the B3LYP/D95(d,p) level on several different cyclic H‐bonding dimers, where the monomers of each are connected by a pair of NH···OC H‐bonding interactions, and the H‐bonding donors and acceptors on each monomer are separated by polarizable spacers. Depending on the structures, the individual H‐bonds vary in strength (enthalpy) by over a factor of four, from 2.41 to 10.99 kcal/mol. We attribute most of the variation in interaction energies to differences in the extent of polarization due to each of the H‐bonds, which can either combine constructively or destructively. The dipole–dipole interactions between the pair of H‐bonds also contribute somewhat to the relative stabilities. The relevance of these results to the design of self‐assembling materials is discussed. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Catalytic degradation of oxygenates in Fischer–Tropsch aqueous phase effluents to fuel gas via hydrodeoxygenation over Ru/AC catalyst
Authors: Chen Lungang , Zhu Yulei , Zheng Hongyan , Zhang Chenghua , Zhang Bin , Li Yongwang 
Published: June 2011

AbstractBACKGROUND: Aqueous phase Fischer–Tropsch (FT) effluents co‐produced with hydrocarbons in the FT process contain various water‐soluble oxygenates, e.g. carboxylic acids, alcohols. Purification of the FT aqueous phase is important from the viewpoint of effective resource utilization and environmental stewardship. In this work, an aqueous‐phase hydrodeoxygenation process was investigated for the degradation of FT aqueous phases.RESULTS: The Ru/AC catalyst was determined to be the most active catalyst. The key parameters, i.e. temperature, pressure, weight hourly space velocity and Ru loading, were comprehensively optimized. Under optimal conditions, ca 98% of the oxygenates were converted to C1∼C6 alkanes. The degraded water had no odour, a neutral pH, and as low as 1000 mg L−1 chemical oxygen demand. The Ru/AC catalyst exhibited long‐term stability (1300 h) and no ruthenium leaching. A reaction pathway is proposed for this process in which the carboxylic acids are hydrogenated to alcohols via the formation of aldehydes. Alcohols and aldehydes are then converted to methane and alkanes of one carbon atom less than the substrate through CC bond cleavage.CONCLUSIONS: This process is effective for treating FT aqueous phase effluent, and holds great promise for industrial applications due to its high efficiency, simplicity and stability. Copyright © 2011 Society of Chemical Industry
Therapeutic ultrasound promotes plasmid DNA uptake by clathrin‐mediated endocytosis
Authors: de Paula Daisy Maria Bentes , Valero‐Lapchik Valderez Bastos , Paredes‐Gamero Edgar Julian , Han Sang Won 
Published: June 2011

AbstractBackgroundUltrasound (US) has been widely used to improve the efficiency of nonviral vector transfection. The mechanism of plasmid uptake is usually attributed to sonoporation, although there is not clear evidence for this attribution. Based on our previous results, we hypothesized that other mechanisms, such as endocytosis, could be involved in this process.MethodsNIH3T3 cells were transfected with plasmid vector pEGFP‐N3 (4.7 kb) using a therapeutic US without microbubbles. Bioeffects such as calcium influx, reactive oxygen species (ROS) generation and membrane potential alterations were accessed with fluorescent dyes in real‐time by confocal microscopy after US insonation. Localization of labeled plasmid DNA in cells was also monitored with endocytosis markers using an immunofluorescence assay.ResultsUS at 2 W/cm2 with a duty‐cycle of 20% for 30 s resulted in approximately 40% transfection efficiency but, at 1 W/cm2, resulted in a very low level of transfection. Both the production of ROS and calcium influx were augmented during the insonation, although they were stopped soon after turning off US, with the exception of calcium influx with 1 W/cm2. US also changed the cell membrane potential to the hyperpolarization state, which returned to the normal state soon after insonation. Labeled plasmids DNA could be co‐localized with clathrin‐mediated endocytosis marker but not with caveolin‐1.ConclusionsThe present data indicate that plasmid DNA uptake promoted by US should occur via clathrin‐mediated endocytosis. Copyright © 2011 John Wiley & Sons, Ltd.
Synthesis and structure of substituted 5‐phenoxy‐1,2,4‐dithiazole‐3‐ones
Authors: Ponomarov Oleksandr , Padělková Zdeňka , Hanusek Jiří 
Published: June 2011

AbstractSeven new substituted 5‐phenoxy‐1,2,4‐dithiazole‐3‐ones were prepared in modest yield (53–76%) from corresponding O‐phenyl thiocarbamates and chlorocarbonylsulfenyl chloride in dry ether at −10 °C. All of the compounds were characterized by NMR and elemental analysis and some of them by X‐ray diffraction. Preliminary kinetic measurements showed that the parent 5‐phenoxy‐1,2,4‐dithiazole‐3‐one is a very efficient sulfurizing agent toward triphenyl phosphite. J. Heterocyclic Chem., (2011)
Trajectory compensation in an autoresonant trap mass spectrometer
Authors: Ermakov A. V. , Hinch B. J. 
Published: July 2011

AbstractThe auto‐resonant trap mass spectrometer, ART‐MS, utilizes electrostatic ion trapping within an anharmonic potential well. Ions are detected after mass selective trap ejection with auto‐resonant driving employing only low‐power rf electronics. We identify the major limiting factor in the mass resolution of these instruments. Whilst keeping in the spirit of maintaining a rapid scan rate, low cost, lightweight instrument, with minimal required machining tolerances, we introduce a method for much improving the mass resolutions of an ART‐MS. The addition of two electrodes has enabled an improvement in the mass resolution by a factor of ∼4. The scheme significantly reduces the effects of a finite sized trap and compensates for the influence of radial variation in natural oscillating frequencies within the trap. Compensation can be implemented with a wide range of designs and is not limited by the size of the trap. Copyright © 2011 John Wiley & Sons, Ltd.
Lithium protects against oxidative stress‐mediated cell death in α‐synuclein‐overexpressing in vitro and in vivo models of Parkinson's disease
Authors: Kim Yong‐Hwan , Rane Anand , Lussier Stephanie , Andersen Julie K. 
Published: June 2011

AbstractLithium has recently been suggested to have neuroprotective properties in relation to several neurodegenerative diseases. In this study, we examined the potential cytoprotective effect of lithium in preventing oxidative stress‐induced protein accumulation and neuronal cell death in the presence of increased α‐synuclein levels in vitro and in vivo. Specifically, lithium administration was found to protect against cell death in a hydrogen peroxide‐treated, stable α‐synuclein‐enhanced green fluorescent protein (EGFP)‐overexpressing dopaminergic N27 cell line. Lithium feeding (0.255% lithium chloride) of 9‐month‐old pan‐neuronal α‐synuclein transgenic mice over a 3‐month period was also sufficient to prevent accumulation of oxidized/nitrated α‐synuclein as a consequence of chronic paraquat/maneb administration in multiple brain regions, including the glomerular layer, mitral cells, and the granule cell layer of the olfactory bulb (OB), striatum, substantia nigra pars compacta (SNpc) and Purkinje cells of the cerebellum. Lithium not only prevented α‐synuclein‐mediated protein accumulation/aggregation in these brain regions but also protected neuronal cells including mitral cells and dopaminergic SNpc neurons against oxidative stress‐induced neurodegeneration. These results suggest that lithium can prevent both α‐synuclein accumulation and neurodegeneration in an animal model of PD, suggesting that this drug, already FDA‐approved for use in bipolar disorder, may constitute a novel therapy for another human disease. © 2011 Wiley‐Liss, Inc.
Conformational, vibrational, and structural studies of 2,2,3,3,3‐pentafluoropropylamine from Raman and infrared spectra of gas, liquid, xenon solutions, and solid supported by ab initio calculations
Authors: Guirgis, Gamil A. , Darkhalil, Ikhlas D. , Klaassen, Joshua J. , Ganguly, Arindam , Wyatt, Justin K. , Durig James R. 
Published: June 2011

AbstractThe Raman and infrared spectra (3500–50 cm−1) of the gas, liquid or solution, and solid were recorded of 2,2,3,3,3‐pentafluoropropylamine (CF3CF2CH2NH2) and the ND2 isotopomer. Variable temperature (−55 to − 100 °C) studies of the infrared spectra (3600–400 cm−1) of samples dissolved in liquid xenon have been carried out. From these data, two of the five possible conformers have been identified and their relative stabilities obtained. The enthalpy difference was determined between the more stable Tt conformer and the less stable Tg form to be 280 ± 14 cm−1 (3.35 ± 0.17 kJ/mol). The first indicator is the NCCC dihedral angle (G = gauche or T = trans), and the second one (g = gauche or t = trans) is the relative position of the lone pair of electrons on nitrogen with respect to the β‐carbon. The percentage of the Tg conformer at ambient temperature is estimated to be 34 ± 2%. The conformational stabilities have been predicted from ab initio calculations utilizing several different basis sets up to aug‐cc‐pVTZ for both MP2(full) and density functional theory calculations by the B3LYP method. Vibrational assignments have been provided for most of the observed bands for both isotopomers, supported by MP2(full)/6‐31G(d) ab initio calculations to predict the harmonic force fields, wavenumbers, infrared intensities, Raman activities, and depolarization ratios for both conformers. Estimated r0 structural parameters were obtained from adjusted MP2(full)/6‐311 + G(d,p) calculations. The results are discussed and compared with the corresponding properties of some related molecules. Copyright © 2011 John Wiley & Sons, Ltd.
Hydrogen‐bonding interactions in fully deuterated α‐glycine at high pressures
Authors: Sharma Bharat Bhooshan , Murli Chitra , Chitra R. , Sharma Surinder M. 
Published: June 2011

AbstractRecent spectroscopic investigations of various amino acids report intriguing high‐pressure and low‐temperature behavior of NH3+ groups and their influence on various hydrogen bonds in the system. In particular, the variation of the intensity of NH3+ torsional mode at different temperatures and pressures has received much attention. We report here the first in situ Raman investigations of fully deuterated α‐glycine up to ∼20 GPa. The discontinuous changes in COO− and ND3+ modes across ∼3 GPa indicate subtle structural rearrangements in fully deuterated α‐glycine. The decrease in the intensity of ND3+ torsional mode is found to be similar to that of undeuterated α‐glycine. The pressure‐induced stiffening of ND and CD2 stretching modes are discussed in the context of changes in the hydrogen‐bonding interactions. Copyright © 2011 John Wiley & Sons, Ltd.
Two‐dimensional standoff Raman measurements of distant samples
Authors: Porter John N. , Helsley Charles E. , Sharma Shiv K. , Misra Anupam K. , Bates David E. , Lienert Barry R. 
Published: June 2011

AbstractA scanning standoff Raman spectroscopy system has been developed to measure the molecular species of distant samples in two dimensions. Computer software is used to control the scanner pan and tilt angles, and Raman measurements are collected of the distant sample area in an x–y grid pattern. The Raman spectra at each grid point are measured and processed to obtain an image of the distant surface composition. The ability to provide interpolated images of distant molecular species is illustrated. Copyright © 2011 John Wiley & Sons, Ltd.
Triple‐resonant two‐phonon Raman scattering in graphene
Authors: Kupčić I. 
Published: June 2011

AbstractThe triple‐resonant (TR) second‐order Raman scattering mechanism in graphene is re‐examined. It is shown that the magnitude of the TR contribution to the photon‐G′ mode coupling function in graphene is one order of magnitude larger than the widely accepted two‐resonant coupling. Enhancement of the order of 100 in the Raman intensity, with respect to the usual double‐resonant model, is found for the G′ band in graphene, and is expected in the related sp2‐based carbon materials, as well. Copyright © 2011 John Wiley & Sons, Ltd.
Testing of Raman spectroscopy as a non‐invasive tool for the investigation of glass‐protected miniature portraits
Authors: Mancini Diana , Tournié Aurélie , Caggiani Maria‐Cristina , Colomban Philippe 
Published: July 2011

AbstractSix French miniature portraits on ivory and paper dating back to the 18th to 19th centuries have been studied by Raman spectroscopy. The miniatures have been investigated through their protective glass cover using different operating conditions: various laser wavelengths (1064, 785 and 532 nm), spectrometers (fixed and mobile) and objectives (10× to 200×). The results obtained for black (carbon), grey (carbon + chalk), red (lead oxide, vermillion), blue (Prussian or phthalocyanine blue), green (emerald or Paris green) and white (lead white) pigments are presented. The consistency of the period of use of the pigments with the proposed dating for each artwork is evaluated. Attention is paid to the analysis of the ivory substrates (assigned to Asian elephant ivory) and to the protective glass. Copyright © 2011 John Wiley & Sons, Ltd.
Zincon as resonance Raman probe for quantitative evaluation of proteins
Authors: Chen Lei , Park Yeonju , Seo Hyeongkuyn , Hong Wonjin , Jung Young Mee , Zhao Bing 
Published: June 2011

AbstractThis paper demonstrates the potential of using a resonance Raman (RR) based method for the quantitative evaluation of protein concentrations. This method was applied to determine the concentration of bovine serum albumin (BSA) protein using zincon. In the protein–zincon liquid mixture, the number of unbound zincon molecules decreased markedly as the protein concentration increased because of the high affinity of zincon for proteins. We successfully detected very low concentrations of BSA (∼1 ng/ml) using this method, which demonstrates its great potential for the detection of proteins over a much wider range of concentrations in proteomic studies. This new RR‐based method allows the detection of proteins in lower concentration than with the UV–vis‐based and other protein assays commonly used in biochemical laboratories. Copyright © 2011 John Wiley & Sons, Ltd.