bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bisphosphonate treatment delays stress fracture remodeling in the rat ulna
Authors: Kidd L.J. , Cowling N.R. , Wu A.C.K. , Kelly W.L. , Forwood M.R. 
Published: May 2011

AbstractBecause bisphosphonates (BPs) are potent inhibitors of bone resorption, we hypothesized that they would retard direct remodeling of stress fractures. The aim of this study was to determine the effect of risedronate on direct remodeling and woven bone callus formation following stress fracture formation in the rat ulna. In 135 adult female Wistar rats, cyclic loading of the ulna created stress fractures. Rats were treated daily with oral saline, or risedronate at 0.1 or 1.0 mg/kg. From each bone, histomorphometry was performed on sections stained with toluidine blue at a standard level along the fracture. The high dose of risedronate caused a significant decrease in the percentage of repaired stress fracture and bone resorption along the stress fracture line at 6 and 10 weeks after loading (p < 0.05). At this dose, intracortical resorption was significantly reduced at 10 weeks after loading and intracortical new bone area was significantly reduced at 6 and 10 weeks. Woven bone formation and consolidation phases of stress fracture repair were not affected by low or high doses of risedronate. In conclusion, high dose bisphosphonate treatment impaired healing of a large stress fracture line by reducing the volume of bone resorbed and replaced during remodeling. We also confirmed that periosteal callus formation was not adversely affected by risedronate treatment. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29:1827–1833, 2011
Determination of free cyanide and zinc cyanide complex by capillary electrophoresis
Authors: Langeroudi Elahe Ghasemian , Petre Catalin Florin , Azizi Abdelaaziz , Proulx Eric , Larachi Faïçal 
Published: May 2011

AbstractA capillary electrophoretic (CE) protocol was developed for the separation and quantification of free cyanide and zinc cyanide complex, two key species in gold cyanidation of zinc‐bearing sulfidic ores. Several common carrier electrolytes were implemented in an indirect UV detection method. The effect of electric field strength, injection volume, concentration of electro‐osmotic flow (EOF) modifier and UV‐absorbing agent in background electrolyte (BGE) was examined while peak height, peak area and noise were considered for optimization. The best results were obtained using a BGE that contained 35 mM sodium chromate, 12 mM free cyanide and 0.45 mM hexamethonium bromide at pH 10.5. Free cyanide concentration was compared to that measured with the conventional silver nitrate titration method in solutions containing free cyanides and weak cyano‐complexes. The developed CE protocol proved very robust in capturing the concentration of free cyanides (4% error) unlike the titration method which exhibited substantial sensitivity to the interfering weak cyano‐complexes (38% error).
Analysis of abuse drugs in urine using surfactant‐assisted dispersive liquid–liquid microextraction
Authors: Moradi Morteza , Yamini Yadollah , Baheri Tahmineh 
Published: May 2011

AbstractThe process of surfactant‐assisted dispersive liquid–liquid microextraction (SA‐DLLME) followed by high‐performance liquid chromatography‐UV detection was successfully applied for the extraction and determination of selected cannabinoids (cannabidiol, Δ9‐tetrahydrocannabinol, and cannabinol) in urine samples. The effective parameters on the extraction efficiency were studied and optimized utilizing two different optimization methods: one variable at a time (OVAT) and face center design (FCD). Under the optimum conditions (extraction solvent and its volume, toluene, 85 μL; disperser agent and its concentration, 1.0 mL of ultra‐pure water containing 0.5 mmol/L tetradecyl tremethyl ammonium bromide (TTAB); sample pH, 2.0 and salt concentration, 11% w/v NaCl), the limits of detection of the method were in the range of 0.1–0.5 μg/L and the repeatability and reproducibility of the proposed method, expressed as relative deviation, varied between 4.1 and 8.5% and 6.7 and 11.6%, respectively. Linearity was found to be in the range of 1.0–200 μg/L and under the optimum conditions, the preconcentration factors (PFs) were between 190 and 292. This proposed method was successfully applied in the analysis of three male advocate urine samples and good recoveries were obtained.
Enthalpy–entropy compensation effect on adsorption of light hydrocarbons on monolithic stationary phases
Authors: Korolev Alexander A. , Shiryaeva Valeria E. , Popova Tamara P. , Kurganov Alexander A. 
Published: May 2011

AbstractEnthalpy and entropy of adsorption of light hydrocarbons C1–C4 have been measured for three monoliths of different polarity and for five different carrier gases: helium, hydrogen, nitrogen, carbon dioxide and dinitrogen oxide. Using carrier gas helium the highest values of enthalpy and entropy were observed for monolith based on ethylenedimethacrylate and the lowest values were observed for monolith based on silica, while monolith based on divinylbenzene demonstrated intermediate values. Entropy–enthalpy correlations were observed with carrier gas helium for all thee monoliths and possess similar slope indicating similar adsorption mechanism on all monoliths studied. Comparing different carrier gases entropy–enthalpy correlations within a homological series of solutes were observed for light carrier gases (He, H2 and N2) and were not observed for heavy carrier gases (CO2 and N2O). Instead, entropy–enthalpy correlations for heavy carrier gases were observed with pressure as variable and the higher the carrier gas pressure the lower the values of enthalpy and entropy observed. The observed changes in entropy–enthalpy correlations were explained by competitive adsorption of heavy carrier gas on monoliths.
Determination of ammonium in wastewaters by capillary electrophoresis on a column‐coupling chip with conductivity detection
Authors: Luc Milan , Kruk Pavol , Masár Marián 
Published: May 2011

AbstractAnalytical potentialities of a chip‐based CE in determination of ammonium in wastewaters were investigated. CZE with the electric field and/or ITP sample stacking was performed on a column‐coupling (CC) chip with integrated conductivity detectors. Acetate background electrolytes (pH ∼3) including 18‐crown‐6‐ether (18‐crown‐6) and tartaric acid were developed to reach rapid (in 7–8 min) CZE and ITP‐CZE resolutions of ammonium from other cations (sodium, potassium, calcium and magnesium) present in wastewater samples. Under preferred working conditions (suppressed hydrodynamic flow (HDF) and EOF on the column‐coupling chip), both the employed methods did provide very good repeatabilities of the migration (RSD of 0.2–0.8% for the migration time) and quantitative (RSD of 0.3–4.9% for the peak area) parameters in the model and wastewater samples. Using a 900‐nL sample injection volume, LOD for ammonium were obtained at 20 and 40 μg/L concentrations in CZE and ITP‐CZE separations, respectively. Very good agreements of the CZE and ITP‐CZE determinations of ammonium in six untreated wastewater samples (only filtration and dilution) with the results obtained by a reference spectrometric method indicate a very good accuracy of both the CE methods presented.
Phosphorus and Silicon Containing Low‐Melting Organic–Inorganic Glasses Improve Flame Retardancy of Epoxy/Clay Composites
Authors: Yu Dan , Kleemeier Malte , Wu Guang Mei , Schartel Bernhard , Liu Wei Qu , Hartwig Andreas 
Published: May 2011

AbstractNew low‐melting organic–inorganic glassy polymers containing phosphorus and silicon are synthesized by the reaction between phenylphosphonic acid and methyltrichlorosilane or methyltriethoxysilane. They possess both low‐softening points and high onset decomposition temperatures, which are favorable for preparing flame retardant composites. Although the glass by itself is sensitive to water, the composites are not significantly affected in that way. For glass/clay/epoxy composites glass transition temperature (Tg) as well as storage modulus increase with the glass amount. The glasses improve flame retardancy significantly due to flame inhibition and the formation of fire residue working as protection layer during burning. The total heat evolved is reduced by 23–28% for using 5–15 wt.% glass and the maximum HRR even by 58–48%. The latter effect decreases with increasing glass amount due to an adulterate residue deformation. The combination of glass and clay is proposed as a possible route to enhance flame retardancy. magnified image
The β Phase Formation Limit in Two Poly(9,9‐di‐n‐octylfluorene) based Copolymers
Authors: Bright Daniel W. , Moss Kathryn C. , Kamtekar Kiran T. , Bryce Martin R. , Monkman Andrew P. 
Published: May 2011

AbstractRandom copolymers of poly(9,9‐di‐n‐octylfluorene) (PF8) incorporating 0, 8, 12, 15, and 20% dibenzothiophene (DBT), and copolymers with 2, 5, 8, 12, and 15% dibenzothiophene‐S,S‐dioxide (S‐unit) were synthesised. Absorption and emission spectra of thin films indicate that the DBT system shows a linear decrease of toluene vapour induced β phase with increasing DBT content to a 20% cutoff, whilst in the S‐unit copolymers the β phase is present up to 12% co‐monomer content, and at 15% the characteristic absorption peak is absent or masked. These results demonstrate the limits, in thin films, at which the β phase can be formed in widely used PF8 copolymer systems for device applications and clearly show that it is practical to use copolymers having electron or hole transport units in the polyfluorene backbone and still be able to form efficient β phase emission sites. magnified image
Green tea extract ameliorates reperfusion injury to rat livers after warm ischemia in a dose‐dependent manner
Authors: Liang Rui , Nickkholgh Arash , Kern Michael , Schneider Heinz , Benzing Steffen , Zorn Markus , Büchler Markus W. , Schemmer Peter 
Published: May 2011

AbstractScope: Polyphenolic constituents of green tea (Camellia sinensis) have been shown to be potent scavengers of reactive oxygen species (ROS). Thus, this study was designed to assess its effects after liver ischemia–reperfusion.Methods and results: Fasted Sprague–Dawley rats were gavaged with different concentrations of green tea extract (GTE) 2 h before 90 min of warm ischemia of the left lateral liver lobe (30% of liver). Controls were given the same volume of Ringer's solution. A preparation of pentobarbital sodium (intraperitoneal) and ketamine (intramuscular) was used for anesthesia. After reperfusion, transaminases, liver histology, hepatic microcirculation, and both phagocytosis of latex bead particles as well as the expression of tumor necrosis alpha (TNF‐α) to index cellular activation were investigated. Furthermore, the expression of superoxide dismutase (Mn‐SOD) was assessed. After 90 min of warm ischemia aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) increased dramatically to 1946±272/3244±757 U/L, 1680±134/2080±379 U/L, and 7857±1851/2036±1193 U/L at 2/6 h, respectively. GTE (200 mg/kgbody weight) significantly prevented this increase in a dose‐dependent manner by 21–51% at 2 h and 29–34% at 6 h, respectively. Histology confirmed the protective effects while both TNF‐α expression and phagocytosis of latex beads by Kupffer cells (KCs) were significantly reduced. GTE intake significantly increased the expression of manganese superoxide dismutase. In vivo microscopy revealed improved acinar and sinusoidal perfusion after GTE.Conclusion: Preconditioning with a single oral dose of GTE ameliorates ischemia–reperfusion injury in liver. Decreased cellular activation and improved microcirculation are the proposed mechanisms.
Green and black tea in relation to gynecologic cancers
Authors: Butler Lesley M. , Wu Anna H. 
Published: May 2011

AbstractScope: Observational studies have evaluated the relationship between green tea intake and cancers of the ovary and endometrium, but we are not aware of the published studies on green tea intake and risk of human papillomavirus (HPV)‐related cancers of the cervix, vagina, or vulva.Methods and results: A critical review of the published literature on tea intake and risk of ovarian and endometrial cancers was conducted. In meta‐analyses, we report inverse associations for green tea intake and risk of ovarian cancer (odds ratio [OR]=0.66; 95% confidence interval [CI]: 0.54, 0.80), and for green tea and risk of endometrial cancer (OR=0.78, 95% CI: 0.62, 0.98). There was no association for black tea and ovarian cancer risk (OR=0.94, 95% CI: 0.87, 1.02) and a positive association with endometrial cancer risk (OR=1.20, 95% CI: 1.05, 1.38). We summarized the experimental evidence supporting the antiviral and immunomodulatory activities of green tea catechins, and results from randomized clinical trials that demonstrated green tea catechin efficacy on treatment of cervical lesions and external genital warts.Conclusion: Observational data support a protective role of green tea on risk of ovarian and endometrial cancers. Observational data are needed to evaluate whether green tea reduces risk of human papillomavirus‐related cancers.
Mechanisms of proton spin dephasing in a system of magnetic particles
Authors: de Haan Hendrick W. 
Published: May 2011

AbstractFor protons diffusing among a system of magnetic particles, the process by which initial phase coherence is lost depends substantially on particle size. In this article, evidence for three dephasing mechanisms is presented: an incremental process at small particle sizes (motional averaging regime), a discrete process at intermediate particle sizes (visit limited regime), and a continuous process at large particle sizes (static dephasing regime). While motional averaging regime and static dephasing regime are well known, the distinct dynamics in visit limited regime are often overlooked. Revisiting earlier analytic treatments for the dynamics in this regime, Monte Carlo simulations are performed to extract the details of dephasing and to test the concept of an inner zone of rapid dephasing herein named the full dephasing zone. It is shown that the emergence of a full dephasing zone marks the transition from motional averaging regime to visit limited regime since protons can be fully dephased in a single encounter. Moving from the visit limited regime to the static dephasing regime, a crossover between a purely discrete process and a purely continuous process occurs. Developing a simple model of the dephasing process, the average dephasing time is demonstrated to be relatively constant thus giving insight into the long lasting plateau in the relaxation rate. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Functional characterization of EMSY gene amplification in human cancers
Authors: Wilkerson Paul M , Dedes Konstantin J , Wetterskog Daniel , Mackay Alan , Lambros Maryou B , Mansour Marthe , Frankum Jessica , Lord Christopher J , Natrajan Rachael , Ashworth Alan , Reis‐Filho Jorge S 
Published: May 2011

AbstractThe 11q13‐q14 locus is frequently amplified in human cancers, with a complex structure harbouring multiple potential oncogenic drivers. The EMSY gene has been proposed as a driver of the third core of the 11q13‐q14 amplicon. This gene encodes a protein reported to be a BRCA2‐binding partner, which when over‐expressed would lead to impairment of BRCA2 functions and could constitute a mechanism for BRCA2 inactivation in non‐hereditary breast and ovarian cancers. We hypothesized that if EMSY amplification abrogates BRCA2 functions, cells harbouring this aberration would be unable to elicit competent homologous recombination DNA repair and, therefore, may have increased sensitivity to genotoxic therapies and potent PARP inhibitors. Microarray‐based comparative genomic hybridization of cell lines from distinct tumour sites, including breast, ovary, pancreas, oesophagus, lung and the oral cavity, led to the identification of 10 cell lines with EMSY amplification and 18 without. EMSY amplification was shown to correlate with EMSY mRNA levels, although not all cell lines harbouring EMSY amplification displayed EMSY mRNA or protein over‐expression. RNA interference‐mediated silencing of EMSY did not lead to a reduction in cell viability in tumour models harbouring EMSY amplification. Cell lines with and without EMSY amplification displayed a similar ability to elicit RAD51 foci in response to DNA damaging agents, and similar sensitivity to cisplatin and olaparib. Taken together, this suggests that EMSY is unlikely to be a driver of the 11q13‐q14 amplicon and does not have a dominant role in modulating the response to agents targeting cells with defective homologous recombination. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Vertical junction Si cells for concentrating photovoltaics
Authors: Pozner Roni , Segev Gideon , Sarfaty Rona , Kribus Abraham , Rosenwaks Yossi 
Published: May 2011

ABSTRACTVertical junction Si cell has shown a potential to operate at high concentrations, mainly the result of reduced series resistance losses due to its low‐current/high‐voltage design, but tests and analyses have so far only shown a modest efficiency of about 20%. We perform a comprehensive optimization study and show that the conversion efficiency of vertical multi‐junction (VMJ) cells can be significantly higher, close to 30% at concentrations of 1000 and higher. Reaching this efficiency requires junction dimensions that are significantly smaller than previous VMJ cells. This may require a different approach in the fabrication process, possibly by using a monolithic method rather than the wafer stacking approach. We also show that increased photoconductivity, which is usually negligible in conventional cells, produces a significant reduction in series resistance at high concentrations making it a significant contributor to the outstanding performance of the VMJ cell at high concentration. Copyright © 2011 John Wiley & Sons, Ltd.
Fabrication of dye sensitized solar cell using Cr doped CuZnSe type chalcopyrite thin film
Authors: Joseph D. Paul , Ganesan S. , Kovendhan M. , Suthanthiraraj S. Austin , Maruthamuthu P. , Venkateswaran C. 
Published: May 2011

AbstractChalcopyrites are a versatile class of semiconductors known for their potential in photovoltaic applications. Considering the well established CuInSe2 as a prototype system, a new compound of the chalcopyrite type, Cu1–xZn1–ySe2–δ, by replacing In with Zn, has been prepared (both undoped and 2% Cr doped) by the metallurgical method. Thin films have been deposited by the thermal evaporation technique using the stabilized polycrystalline compounds as charge. Structural, compositional, morphological, and optical properties of the films are analyzed and reported. Use of these films as electrodes in dye sensitized solar cell (DSSC) is demonstrated.
InGaN/GaN short‐period superlattices: synthesis, properties, applications
Authors: Tsatsulnikov A. F. , Lundin W. V. , Sakharov A. V. , Zavarin E. E. , Usov S. O. , Nikolaev A. E. , Kryzhanovskaya N. V. , Sizov V. S. , Synitsin M. A. , Yakovlev E. V. , Chernyakov A. E. , Zakgeim A. L. , Cherkashin N. A. , Hytch M. 
Published: May 2011

AbstractInGaN/GaN short‐period superlattices were fabricated using method based on cycle conversion of surface InGaN layer to GaN by applying of growth interruptions in hydrogen atmosphere. SPSLs having total thickness from 12 nm to 120 nm were grown and investigated by combination of optical methods, XRD and high resolution transmission electron microscopy (HRTEM) with geometric phase analysis. Blue, deep green (540‐560 nm) and monolithic white LEDs (containing in active region green and blue InGaN QWs separated by the SPSL or GaN barrier) were grown and investigated. Deep green LEDs have maximal external quantum efficiency of 8‐16% in the range of 560‐540 nm correspondingly. Monolithic white LED structures with CCT in the range of 5000‐6000 K have maximal external quantum efficiency of more than 6%. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Origin of the “green gap”: Increasing nonradiative recombination in indium‐rich GaInN/GaN quantum well structures
Authors: Langer Torsten , Kruse Andreas , Ketzer Fedor Alexej , Schwiegel Alexander , Hoffmann Lars , Jönen Holger , Bremers Heiko , Rossow Uwe , Hangleiter Andreas 
Published: May 2011

AbstractUsing time‐resolved photoluminescence spectroscopy on GaInN/GaN multiple quantum well structures, we analyze the radiative and nonradiative processes contributing to the “green gap” in GaN‐based light emitting devices. We observe that it is only partly caused by a reduced oscillator strength due to the Quantum Confined Stark Effect (QCSE) which becomes stronger with increasing indium concentration and well width.As the dominant effect we observe a reduction of nonradiative lifetimes when the indium concentration is increased. For higher indium concentrations, we find an additional nonradiative recombination path that might be attributed to an increased generation of defects like misfit dislocations, nitrogen vacancies and/or indium clusters within the optically active region. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Improved quantum efficiency of 350 nm LEDs grown on low dislocation density AlGaN buffer layers
Authors: Kunzer Michael , Gutt Richard , Kirste Lutz , Passow Thorsten , Forghani Kamran , Scholz Ferdinand , Köhler Klaus , Wagner Joachim 
Published: May 2011

AbstractThe effect of buffer layers with reduced defect density on the efficiency of AlGaN based UV LED structures has been investigated. We report on two approaches of defect reduction: Firstly, AlGaN was grown on thin GaN nucleation islands which exhibit a three‐dimensional facetted structure (3D nucleation). Secondly, AlGaN buffer layers with in‐situ SiNx nano‐masking interlayers inserted were employed. Both approaches result in reduced widths of asymmetric high‐resolution X‐ray diffraction ω‐scan peaks. Full LED structures were grown on these buffer layers and are compared to structures grown on a purely 2D grown low Al‐content AlGaN nucleation layer. The influence of the different buffer layer technologies, and hence defect density, on the quantum efficiency has been investigated by excitation‐density and temperature dependent photoluminescence. The data indicate an increase in the PL efficiency from below 5% for 2D nucleation to 15% for 3D nucleation and up to 50% for structures grown on SiNx interlayer buffers. These results are in line with electroluminescence measurements taken on‐wafer. The output power at 40 mA emitted through the substrate for the 3D nucleated LED structure is 0.3 mW which corresponds to an increase by a factor of 9 compared to similar LED structures grown in 2D mode. The same LED structure grown on an AlGaN buffer containing SiNx interlayers showed a 30× enhancement in efficiency with an output power of 0.51 mW at 20 mA, rising linearly to 1.05 mW for a current of 40 mA (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical behavior of GaN‐HEMT after fluoride plasma treatment
Authors: Dagher Gulnar , Nguyen Thi Dak Ha , Péré‐Laperne Nicolas , Mimila‐Arroyo Jaime , Lijadi Melania , Jomard François , Dupuis Christophe , Bardou Nathalie , Pelouard Jean‐Luc 
Published: May 2011

AbstractEffects of fluorine‐based plasma treatment on the GaN‐based HEMTs electrical properties have been investigated. Two structures have been studied and compared, one with AlGaN alloy barrier and another one with AlN/GaN super‐lattice (SL) barrier. Firstly a large positive threshold voltage (Vth) shift in the structure with AlGaN alloy barrier is observed. Vth shift is due to the incorporation of fluorine into the barrier. As a consequence the 2D‐electron gas density is lower and Vth enlarges. Secondly a small negative Vth shift is obtained in the structure with an AlN/GaN SL barrier. It has been attributed to fluorine n‐type doping in the SL barrier (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)