bluuebunny/crossref_metadata_2025_split huggingface dataset:
Association between thyroid hormones, lipids and oxidative stress biomarkers in overt hypothyroidism
Authors: Santi Adriana , Duarte Marta Maria Medeiros Frescura , Moresco Rafael Noal , Menezes Charlene , Bagatini Margarete Dulce , Schetinger Maria Rosa Chitolina , Loro Vania Lucia 
Published: August 2010

Abstract

Background: The aim of this study was to investigate the effect of hypothyroidism on lipid peroxidation and the antioxidant profile, as well as to evaluate the interaction between thyroid hormones and biomarkers of oxidative stress in patients with overt hypothyroidism. We also evaluated the influence of cholesterol concentrations on biomarkers of oxidative stress in these same patients.

Methods: Total cholesterol (TC), high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides, thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD), catalase (CAT), and vitamin E were measured in 20 subjects with overt hypothyroidism (OH) and 20 controls.

Results: TC, LDL cholesterol, triglycerides, TBARS, SOD, CAT, and vitamin E were significantly higher in the OH group. Significant correlation was observed for TSH and SOD, CAT, vitamin E and TBARS. Correlation was observed for triiodothyronine (T3) and SOD, CAT, vitamin E and TBARS. Significant correlation was also observed for free thyroxine and vitamin E and TBARS. However, correlation between T3 and CAT remained significant after controlling for TC concentrations.

Conclusions: Overt hypothyroidism is associated with an increase in oxidative stress, and hypercholesterolemia has a stronger influence on development of oxidative stress in hypothyroid conditions compared with thyroid hormones.
Clin Chem Lab Med 2010;48:1635–9.
An on-line solid phase extraction procedure for the routine quantification of urinary methylmalonic acid by liquid chromatography-tandem mass spectrometry
Authors: Kirchhoff Fabian , Lorenzl Stephan , Vogeser Michael 
Published: August 2010

Abstract

Background: The goal of this study was to develop and to validate an improved isotope-dilution-liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of methylmalonic acid (MMA) in urine.

Methods: A previously described sample preparation protocol requires two solvent extraction steps, including evaporation. The first extraction is to extract the analyte from the sample, and second occurs following derivatization of the extract. In the method described here, the second evaporation step was substituted by on-line solid phase extraction employing column-switching and a permanent co-polymer based extraction cartridge. A standard validation protocol was applied to investigate the performance of the method.

Results: The method was found to be linear in the clinically relevant range of concentrations (6–100 μmol/L). Total coefficients of variation were below 10% and inaccuracy was <10% for quality control samples at three concentrations.

Conclusions: By omitting one evaporation step, the semi-automated method described in this article enables for more convenient work-flow in the quantification of urinary MMA compared to the previous protocol. This is of relevance for MMA measurement in the routine clinical laboratory setting. Validation demonstrated acceptable analytical performance.
Clin Chem Lab Med 2010;48:1647–50.
Impact of glucuronide interferences on therapeutic drug monitoring of posaconazole by tandem mass spectrometry
Authors: Krüger Ralf , Vogeser Michael , Burghardt Stephan , Vogelsberger Rita , Lackner Karl J. 
Published: August 2010

Abstract

Background: Posaconazole is a novel antifungal drug for oral application intended especially for therapy of invasive mycoses. Due to variable gastrointestinal absorption, adverse side effects, and suspected drug-drug interactions, therapeutic drug monitoring (TDM) of posaconazole is recommended.

Method: A fast ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for quantification of posaconazole with a run-time <3 min was developed and compared to a LC-MS/MS method and HPLC method with fluorescence detection.

Results: During evaluation of UPLC-MS/MS, two earlier eluting peaks were observed in the MRM trace of posaconazole. This was only seen in patient samples, but not in spiked calibrator samples. Comparison with LC-MS/MS disclosed a significant bias with higher concentrations measured by LC-MS/MS, while UPLC-MS/MS showed excellent agreement with the commercially available HPLC method. In the LC-MS/MS procedure, comparably wide and left side shifted peaks were noticed. This could be ascribed to in-source fragmentation of conjugate metabolites during electrospray ionisation. Precursor and product ion scans confirmed the assumption that the additional compounds are posaconazole glucuronides. Reducing the cone voltage led to disappearance of the glucuronide peaks. Slight modification of the LC-MS/MS method enabled separation of the main interference, leading to significantly reduced deviation.

Conclusions: These results highlight the necessity to reliably eliminate interference from labile drug metabolites for correct TDM results, either by sufficient separation or selective MS conditions. The presented UPLC-MS/MS method provides a reliable and fast assay for TDM of posaconazole.
Clin Chem Lab Med 2010;48:1723–31.
Proatrial natriuretic peptide is a better predictor of 28-day mortality in septic shock patients than proendothelin-1
Authors: Guignant Caroline , Venet Fabienne , Voirin Nicolas , Poitevin Françoise , Malcus Christophe , Bohé Julien , Lepape Alain , Monneret Guillaume 
Published: August 2010

Abstract

Background: Septic shock is a major health care problem that affects a heterogeneous population of patients. To improve sepsis management, a key point is to decrease this heterogeneity by stratifying patients according to specific criteria, such as appropriate biomarkers. As the early phase of septic shock is characterized by cardiovascular dysfunction, precursors of vasoactive hormones represent interesting candidates. The objective of the present study was to concomitantly assess the predictive value of C-terminal proendothelin-1 and midregional proatrial natriuretic peptide (CT-proET-1 and MR-proANP, respectively vasoconstrictor and vasodilator) on 28-day mortality following septic shock.

Methods: In this observational study which included 99 patients, concentrations of MR-proANP and CT-proET-1 were measured using an immunoluminometric assay three times within the first week after the onset of septic shock.

Results: While MR-proANP concentrations were significantly increased in non-survivors in comparison with survivors, no differences were noted for CT-proET-1. Increased MR-proANP concentrations were significantly associated with mortality after both univariate and multivariate analyses, adjusted for usual clinical confounders [SAPS II (simplified acute physiology score II), SOFA (sepsis-related organ failure assessment) scores and number of co-morbidities].

Conclusions: In septic shock patients, MR-proANP appears to be a good predictor of 28-day mortality, whereas CT-proET-1 does not present any predictive value during monitoring.
Clin Chem Lab Med 2010;48:1813–20.
Adrenocortical carcinoma and pregnancy: clinical and biological features and prognosis
Authors: Abiven-Lepage Gwenaëlle , Coste Joël , Tissier Frédérique , Groussin Lionel , Billaud Line , Dousset Bertrand , Goffinet François , Bertagna Xavier , Bertherat Jérôme , Raffin-Sanson Marie-Laure 
Published: August 2010

ObjectiveAdrenocortical carcinoma (ACC) is a rare, severe disease. Pregnancy-associated ACC has rarely been reported. We wished to evaluate the characteristics and prognosis of ACC diagnosed in patients during pregnancy or in thepostpartumperiod, comparing them with those for ACC diagnosed in nonpregnant women.DesignClinical presentation, hormonal secretion, staging, survival, and obstetric data are reported. Patients were included between 1963 and 2007. Mean follow-up was 48 months.Patients and methodsThis is a retrospective cohort study carried out at a referral center. All female patients aged 16–49 years diagnosed with ACC during the observation period were included (n=110). Twelve of these women were pregnant or in the first 6 months after delivery. Hormonal secretion, staging, obstetric data, and survival were analyzed. For the survival analysis, pregnant patients were compared with a subgroup of nonpregnant women matched for age, stage, and year of diagnosis (1 pregnant patient/2 controls).ResultsAdrenocortical tumors diagnosed during pregnancy or in thepostpartumperiod tend to be more often cortisol-secreting tumors (P=0.06) and to be discovered at a more advanced stage than those in nonpregnant women, although the differences were not significant. Fetal outcome was poor. Overall survival of the mother was worse than that of matched controls (hazard ratio of death: 3.98, confidence interval=1.34–11.85,P=0.013).ConclusionACC diagnosed during pregnancy or in thepostpartumperiod is associated with a poor fetal outcome and a poorer prognosis than ACC diagnosed in nonpregnant women.
Microstructural, Electrical-, Magneto-Transport Properties of Grain Size Modulated Nanocrystalline Nd0.67Sr0.33MnO3 CMR Manganites
Authors: Paul S. , Nath T. K. 
Published: August 2010

ABSTRACTWe have investigated the effect of nanometric grain sizes on Microstructural, electrical-, magneto-transport and magnetic behaviors in nanocrystalline Nd0.67Sr0.33MnO3 CMR manganites. Three nanocrystalline powders of Nd0.67Sr0.33MnO3 were synthesized through chemical route “Pyrophoric Reaction Process” and calcined for 5 hrs at calcinations temperature (TCal = 650°C, 750°C, and 850°C). XRD patterns indicate that all the synthesized powders have pseudo-cubic perovskite structure without any secondary impurity phase. Using Debye Scherrer formula we calculated the crystallites size for three nanocrystalline Nd0.67Sr0.33MnO3 powders (∼ 30, 40, and 54 nm for TCal = 650°C, 750°C, and 850°C respectively). TEM micrographs show that the average particle sizes are in nanometric regime (ψ ∼ 30–50 nm). In AC susceptibility and resistivity measurement we observed that there is an almost constant Curie temperature (TC) has value around 240 K and gradual decrease of metal-insulator transition temperature (TP) (from 200-129 K) with decrease of TCal. The magneto resistance of ultra fine nanoparticles increases with grain sizes. Highest magnetoresistance observed ∼ 24 for Nd0.67Sr0.33MnO3 with TCal = 850°C. Experimental results revels, the effect of nanometric grain sizes has an important impact in magnetic properties and magneto-transport behaviors.
Delta-phase manganese gallium on gallium nitride: a magnetically tunable spintronic system
Authors: Wang Kangkang , Chinchore Abhijit , Lin Wenzhi , Smith Arthur , Sun Kai 
Published: August 2010

ABSTRACTFerromagnetic delta-phase manganese gallium with Mn:Ga ratio between 1:1 to 1.5:1 is grown on wurtzite gallium nitride and scandium nitride substrates, using molecular beam epitaxy. The dependencies of growth properties, e.g. interface formation, surface reconstruction and crystalline quality, on substrate crystallographic structure and polarity are investigated. Results suggest that for growth on wurtzite GaN, Ga-polar surface promotes quicker interface formation, and also results in better crystalline quality of the MnGa film, as compared to N-polar. The crystal orientation and magnetic anisotropy are found to be different than those grown on cubic scandium nitride substrates.
Synthesis and Magnetic Properties of Nanocomposite Magnets Self-Organized from FeB-Nd-Nb Metallic Glasses
Authors: Tamura R , Kobayashi S , Fukuzaki T , Kamiko M 
Published: August 2010

ABSTRCTChange of the magnetic property of Fe-B-Nd-Nb alloys was investigated with replacing Nb by a glass forming element Zr under constant quenching rate as well as heat treatment conditions. As a result, the coercivity significantly increases up to 1207 kA/m when the half of Nd is replaced by Zr, which is presumably due to grain refinement of the Nd2Fe14B phase. The self-organized nanograin magnets are attractive for future applications since their coercivity can be further improved by reducing the grain size via optimizing the Zr concentration, the quenching rate and the subsequent heat treatment condition.
Optical Properties and Thermal Effects in CaSZ and YSZ Single Crystal by Raman Scattering, Photoluminescence and Absorption Spectroscopy
Authors: Torres Dorcas I. , Llopis José 
Published: August 2010

AbstractTemperature dependent Photoluminescence (PL) and Raman spectra have been used to study the defect structure of untreated and thermochemically reduced calcia stabilized zirconia (CaSZ) and yttria stabilized zirconia (YSZ) single crystals. Over the whole temperature range studied the emission (EM) spectrum of the untreated crystals can be decompose into three broad bands, indicating the presence of several radiative electron transitions which can be associated with anion vacancies centers. Results points out to intrinsic F type centers and extrinsic F type centers (FA, FAA) as the main defect generated in the stabilization process. Effect of thermal reduction on the Raman activity caused a decreased in the acoustic mode region and a shift in the maximum of the excitation (EX) spectra. These variations can be related to a broad absorption band centered at ∼365 nm. This is consistent with a nonrandom arrangement of vacancies, which produces the superposition of periodic sequences of vacancies within domains. Concentration of the color centers was determined by optical absorption in the UV-VIS region. PL temperature dependence study in colored samples suggest that no significant new defect was generated in the reduction process, but a recombination of the charges states of the initial intrinsic and extrinsic F centers.
An Assessment of Layer Development at the Fuel/Cladding Interface During Irradiation of Metallic SFR Fuel Elements
Authors: Keiser Dennis D. , Cole James I. 
Published: August 2010

ABSTRACTTo investigate fuel cladding chemical interaction in irradiated metallic nuclear fuels, diffusion couple experiments have been performed using prototypic metallic fuel alloys with additions of noble metal and lanthanide fission product components mated against stainless steel claddings. The developed interdiffusion zones have been characterized using SEM/EDS/WDS to determine the development of phases and the interdiffusion behavior of specific fuel, cladding, and fission product components. The formed diffusion structures have been compared to actual interaction zones that form in irradiated metallic SFR fuels. This paper discusses how the structures compare between the diffusion couple-generated interdiffusion zones and those that develop in irradiated metallic nuclear fuels. It was found that similarities exist between the phase development and interdiffusion behavior in the annealed diffusion couples and the irradiated fuels. Nd, Mo, and Ru, which were added to a fuel alloy to represent fission products that are present in irradiated metallic nuclear fuels, were found to exhibit interdiffusion behavior in annealed diffusion couples that was similar to what has been observed in actual irradiated metallic fuels. This was also true for the original fuel components U, Pu, and Zr, along with the cladding constituent Fe, Ni, and Cr.
Thermodynamic Properties of Actinide Oxide Solid Solutions
Authors: Shuller Lindsay C. , Pavenayotin Niravun , Ewing Rodney C. , Becker Udo 
Published: August 2010

ABSTRACTDensity functional theory and Monte(Carlo methods were used to investigate the solid( solution behavior of actinide dioxides (AcO2). The end(members of interest include: ZrO2, ThO2, UO2, NpO2, and PuO2; all have the isometric fluorite structure. Ab initio and subsequent Monte( Carlo simulations are used to calculate the excess enthalpy of mixing (ΔHexcess), excess Gibbs free energy of mixing (ΔGexcess), and excess configurational entropy (ΔSexcess) for the above solid(solution series. From ΔGexcess, phase diagrams are derived and miscibility gaps identified. All of the binaries of the aforementioned end(members were studied; however, this paper focuses on the U1(xZrxO2and Np1(xUxO2binaries. About 25 at.% Zr can be in solid solution with the UO2matrix above 1500 K, while Np is completely miscible in the UO2matrix. Partial cation ordering was observed at all temperatures for the U1(xZrxO2binary. The Np1(xUxO2binary approaches perfect cation disorder at high temperatures (2000 K). The cation ordering scheme is not identified in this study because the number of cation(cation interaction parameters was limited by the single unit cell from the ab initio calculations.
Site Occupation and Defect Structure of Fe2Nb Laves Phase in Fe-Nb-M Ternary Systems at Elevated Temperatures
Authors: Ishikawa Shigehiro , Matsuo Takashi , Takata Naoki , Takeyama Masao 
Published: August 2010

AbstractFor the Fe2Nb Laves phase with C14 structure in the Fe-Nb-M (M : Cr, Mn, Co, Ni) systems, the site occupation of M in Fe2Nb has been examined in terms of XRD Rietveld analysis, particularly paying attention to the two Fe sublattice sites of Fe1 (36-net in the triple layer : t) and Fe2 (kagome-net of the single layer : s) with the fraction of 0.25 and 0.75, respectively. In any these four ternary systems, the Fe2Nb Laves phase region largely extends along the equi-Nb concentration direction; for Mn complete solid solubility exists, and the solubility of Cr and Co in Fe2Nb is more than 50 at.% and that of Ni is 44 at.%. Thus, at least two thirds of all Fe sublattices in Fe2Nb are occupied by M in all cases. Rietveld analysis revealed that Cr and Mn with which have a larger atomic size than Fe prefer to occupy the Fe1 sublattice site when the amount in solution is less than 0.25 fraction of Fe in Fe2Nb and the preferred occupation site changes to the Fe2 sublattice site when the amount in solution increases beyond 0.25. In contrast, Co and Ni whose atomic size is smaller than Fe preferentially occupy the Fe2 sublattice site, regardless of the amount. The c/a ratio of stoichiometoric Fe2Nb increases and becomes closer to the ideal value (1.633) of the cubic C15 structure when the Fe1 sublattice site is occupied by Cr and Mn. However, the degree of symmetries of both tetrahedron and kagome-net formed by Fe atoms become better when Fe2 sublattice site is occupied by a certain amount of Ni.
Harmonic Analysis of AlN Piezoelectric Mesa Structures
Authors: Mazumdar Madhulika , Kabulski A. , Farrell R. , Kuchibhatla Sridhar , Pagán V. R. , Korakakis D 
Published: August 2010

AbstractIn this work we report the displacement response of piezoelectric Aluminum Nitride (AlN) thin film MESA in an electrical circuit consisting of a circular MESA in series with a resistance subjected to time varying electrical loads. ANSYS was utilized for the simulation of 3D piezoelectric structures; using coupled field analysis to understand the electro-mechanical behavior of AlN thin film mesas. ANSYS applies finite element analysis (FEM) method to simulate the transient piezoelectric trends. Ringing and overshoot effects were observed in the thin simulation results on applying pulse voltages of varying frequencies to the circuit. The fast rise time of the voltage pulse could be exciting these effects. The effect of fast rising pulse voltages on the RC time constant of the circuit is still unclear at this point and needs to be further investigated.
Integrative Chemistry Toward Designing Polyvinyl Alcohol/Poly-aniline/Vanadium Oxide Nanocomposite-based Macroscopic Fibers: 1D-Highly Sensitive Alcohol Sensors Bearing Enhanced Toughness
Authors: Brun Nicolas , Dexmer Julien , Leroy Céline M. , Sérier Hélène , Steunou Nathalie , Achard Marie-France , Backov Rénal 
Published: August 2010

ABSTRACTPolyvinyl alcohol/Poly-aniline/Vanadium Oxide nanocomposite-based macroscopic fibers have been generated by using a redox reaction addressed while performing an extrusion shaping process. The resulting composites have been thoroughly characterized via a large set of techniques such as SEM, SAXS, XRD and FTIR, in order to determine aniline effects over final materials' structures and properties. Thus, the perturbation of the preferential orientation of the V2O5 nano-ribbons toward the fiber main axis, induced by aniline Red-ox intercalation, has been observed. Also, the partial reduction of V5+ species to V4+ ones, due to the strongly oxidizing character of the first ones toward aniline, has been revealed by Electron Spin Resonance (ESR). Moreover, these fibers are able to detect 5 ppm of ethanol within 3-5 seconds at 42 °C, and possess a toughness of 12 J.g-1.
Photoluminescence Characterization of Hydrogenated Nanocrystalline/Amorphous Silicon
Authors: Fields Jeremy D , Taylor Craig , Radziszewski Juliuz George , Baker David , Yue Guozhen , Yan Baojie 
Published: August 2010

AbstractThe photoluminescence in a nc-Si/a-Si:H mixture has been investigated at varying excitation intensities, and temperatures We have also observed changes in the luminescence spectra, which are induced by sequential annealing at temperatures below the a-Si:H crystallization temperature (˜ 600°C). Two predominant luminescence peaks are observed at ˜ 0.95 eV and ˜ 1.30 eV, which are attributed to band tail-to-band tail transitions near the nc-Si grain boundaries and in the a-Si:H bulk, respectively. The 0.95 eV band saturates approaching 500 mW/cm2 excitation intensity. Annealing the nc-Si/a-Si:H mixture brings out a new low energy peak, centered at ˜ 0.70 eV, and which we believe to be due to oxygen defects.
Improvement of Quantum Efficiency of Amorphous Silicon Thin Film Solar Cells
Authors: Fang Liang , Im Jong-San , Park Sang-Il , Lim Koseng Su 
Published: August 2010

AbstractThe enhancement of optical transmittance at the air/glass interface of amorphous silicon thin film solar cells was shown by application of a nanoporous polymethyl methacrylate (PMMA) antireflection (AR) coating. The PMMA coating was prepared by spin coating of PMMA solution in chloroform in the presence of a small amount of nonane. Because of the difference of the vapor pressure of chloroform and nonane, phase separated structure formed after complete evaporation of both of them during spin coating process. The Corning 1737 glass with the AR coating has high transmittance near 95% from 450-1100nm wavelengths. The amorphous silicon solar cells with the nanoporous PMMA AR coating realize an improvement in quantum efficiency (QE) up to 4% in 450-650nm spectral regions.
Effects of Thinned Multi-Stacked Wafer Thickness on Stress Distribution in the Wafer-on-a-Wafer (WOW) Structure
Authors: Kitada Hideki , Maeda Nobuyuki , Fujimoto Koji , Suzuki Kousuke , Nakamura Tomoji , Ohba Takayuki 
Published: August 2010

AbstractIn the trough silicon via (TSV) structure for 3-dimensional integration (3DI), large thermal-mechanical stress acts in the TSV caused by the mismatch in thermal expansion coefficient (CTE) of the TSV materials. In this study, the stress of multi-stacked thin silicon wafers composed of copper TSV and copper/low-k BEOL structure was analyzed by the finite element method (FEM), aiming to reduce the stress of TSV of 3D-IC. The results of sensitivity analysis using design of experiment (DOE) indicated that the thickness of the silicon and adhesive layer are the key factors for the structural integration of TSV design.