bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and NMR assignment of pentacycloundecane precursors of potential pharmaceutical agents
Authors: Onajole Oluseye K. , Makatini Maya M. , Govender Patrick , Govender Thavendran , Maguire Glenn E. M. , Kruger Hendrik G. 
Published: January 2010

AbstractThe synthesis and complete NMR elucidation of eight novel pentacycloundecane (PCU) derivatives are reported. These compounds are precursors in the synthesis of PCU‐based anti‐tuberculosis (TB) agents and potential human immunodeficiency virus (HIV) protease inhibitors. Two‐dimensional (2D) NMR techniques were used to assign the NMR spectra for these compounds. Substitution of the cage molecule at (C‐8/11) further complicates the assignment, since some of the substituted alkyl chain groups overlap with the cage proton signals. The side chain heteroatoms also introduce a rare through‐space deshielding effect to some of the carbon atoms of the cage skeleton. Ring strain in the rigid cage skeleton appears to induce drastic electronic changes in some parts of the cage framework. This observation is more dramatic for the C‐4 methylene group of the cage diols and the cage ethers. Copyright © 2010 John Wiley & Sons, Ltd.
Association offirst‐trimester low PAPP‐A levels with preterm birth
Authors: Goetzinger Katherine R. , Cahill Alison G. , Macones George A. , Odibo Anthony O. 
Published: January 2010

AbstractObjectiveTo determine the association of, and predictive ability of, pregnancy‐associated plasma protein A (PAPP‐A), free β‐human chorionic gonadotrophin (β‐hCG), and nuchal translucency (NT) with preterm birth (PTB).MethodsA 5‐year retrospective cohort study of women who underwent first‐trimester combined screening was performed. Maternal medical, antepartum, and pregnancy outcome data were obtained. PAPP‐A and β‐hCG were converted to multiples of the median (MoM), and primary exposure was defined as ≤10th percentile MoM for PAPP‐A. Secondary exposures were defined as ≥ 90th percentile MoM for β‐hCG and NT values of ≥ 20 and 25 mm. The primary outcome was PTB before 35 weeks and the secondary outcome was PTB before 32 weeks. Univariate, bivariate, multivariate, and receiver–operator analyses were used.ResultsOf the 2231 patients meeting inclusion criteria with complete outcome data available, 222 had a PAPP‐A level ≤10th percentile MoM. Abnormally low PAPP‐A was associated with an increased risk for PTB < 35 weeks [adjusted odds ratio (aOR) 2.0, 1.0–3.8] and < 32 weeks (aOR 2.7, 1.1–6.4), even after adjusting for prior PTB, tobacco exposure, chronic hypertension, and body mass index. PAPP‐A ≤10th percentile was not sufficiently predictive of PTB < 35 weeks (area under curve = 0.63, 95% CI 0.53–0.72). Neither abnormally high β‐hCG nor increased NT was associated with an increased risk for PTB.ConclusionsPAPP‐A ≤10th percentile is associated with an increased risk for PTB, but is not sufficiently predictive to be used clinically. Copyright © 2010 John Wiley & Sons, Ltd.
Safety assessment of recalled Haemophilus influenzae type b (Hib) conjugate vaccines—United States, 2007–2008
Authors: Huang Wan‐Ting , Chang Soju , Miller Elaine R. , Woo Emily Jane , Hoffmaster Alex R. , Gee Jay E. , Clark Thomas A. , Iskander John K. , Ball Robert , Broder Karen R. 
Published: January 2010

AbstractPurposeOn 13 December 2007, Merck & Co., Inc. voluntarily recalled 1.2 million doses of Haemophilus influenzae type b (Hib) vaccines that had been distributed since April 2007 for concerns regarding potential Bacillus cereus contamination. Enhanced postrecall surveillance was conducted to detect vaccine‐associated B. cereus infections.MethodsWe reviewed reports involving recalled Hib vaccines received by the Vaccine Adverse Event Reporting System (VAERS) during 1 April 2007–29 February 2008. For each reported death, autopsy review sought evidence of B. cereus infections. For each specified outcome, the proportional reporting ratios (PRRs) were calculated to compare the recalled Hib vaccines with the manufacturer's nonrecalled Hib vaccines in the VAERS databases. On 20 December 2007, we used the Epidemic Information Exchange (Epi‐X) to solicit nongastrointestinal vaccine‐associated B. cereus infections, and requested B. cereus isolates for genotyping to compare with the manufacturing facility isolate.ResultsVAERS received 75 reports involving recalled Hib vaccines; none described a confirmed B. cereus infection. Comparative analyses did not reveal disproportionate reporting of specified outcomes for recalled Hib vaccines. The Epi‐X posting triggered one report of vaccine‐associated B. cereus bacteremia from a child who received a nonrecalled Hib vaccine manufactured by Merck; the genotypes of isolates from the patient and the manufacturing facility differed.ConclusionsNo evidence of vaccine‐associated B. cereus infection had been found in recipients of recalled Hib vaccines. Conducting laboratory surveillance through Epi‐X was feasible and may enhance public health response capacities for future vaccine safety emergencies. Published in 2010 by John Wiley & Sons, Ltd.
Open‐circuit voltage increase dynamics in high and low deposition rate polymorphous silicon solar cells
Authors: Johnson E. V. , Dadouche F. , Gueunier‐Farret M. E. , Kleider J. P. , Cabarrocas P. Roca i 
Published: January 2010

AbstractThe dynamics of the open‐circuit voltage (VOC) of polymorphous silicon (pm‐Si:H) solar cells deposited at high and low rates (8 and 1.5 Å/s, HR and LR) and containing lightly or heavily doped p‐layers (LD or HD) are compared through in situ, variable intensity measurements during light‐soaking (LS). The VOC's of the LR cells show an increase with LS, regardless of doping level, whereas the HR cells show decreasing VOC's. This result is in contrast to the changes predicted by the dark diode characteristics, which predict increasing VOC for all the devices. The device measurements are compared to the analogous measurements on co‐deposited coplanar p–i layer stacks to determine whether the VOC dynamics can be linked to changes in the p‐layer doping efficiency during LS. The changes to the macroscopic electrical behaviour of the cell under varying light conditions are modelled using a simple, three parameter function, and are compared to results from a detailed, numerical modelling tool, AFORS‐HET.
Effect of local doping on the electronic properties of epitaxial graphene on SiC
Authors: Červenka Jiří , van der Ruit Kevin , Flipse Kees 
Published: January 2010

AbstractGraphene grown on silicon carbide (SiC) is a promising material for high speed electronic devices. However, for possible future applications it is important to understand the electron properties of this material and how it is affected by the interaction with the SiC interface. Here we report an atomically resolved scanning tunneling microscopy and spectroscopy study of local structural and electronic properties of epitaxial graphene. Sharp localized states from the graphene/SiC(0001) interface have been found to strongly influence the electronic properties of the first graphene layer, causing local doping of graphene layer. The disordered high electron density states have originated from the underlying carbon‐rich interface layer whose structure is discussed.magnified image
Scanning tunneling microscopy images of a first graphene layer on SiC(0001) taken at bias voltage −500 and 500 mV (5 × 5 nm2). Red circles and blue crosses indicate that localized states in the filled and empty electron states belonging to the underlying interface layer are located at different positions.
Electron spin resonance in laser‐crystallized polycrystalline silicon–germanium thin films
Authors: Weizman M. , Scheller L.‐P. , Nickel N. H. , Lips K. , Yan B. 
Published: January 2010

AbstractThe defect properties of laser‐crystallized polycrystalline silicon–germanium (Si–Ge) thin films on glass substrates were investigated with electron spin resonance (ESR) and conductivity measurements. The ESR measurements reveal that laser‐crystallized poly Si1−xGex thin films with 0 < x < 0.84 contain a dangling‐bond concentration of about Ns = 4 × 1018 cm−3, roughly independent of the Ge content in this range. Surprisingly, the ESR signal vanishes completely for the Ge‐rich alloys (x > 0.84) and instead a broad atypical signal appears that we attribute to electric dipole induced spin resonance (EDSR). Samples that showed this behavior exhibited a nearly temperature‐independent electrical conductivity for temperatures between 20 and 100 K. The data are discussed in terms of a model that is based on the formation of a defect band along the grain boundaries in the vicinity of the Fermi level.
Effect of ion energy on structural and electrical properties of intrinsic microcrystalline silicon layer deposited in a matrix distributed electron cyclotron resonance plasma reactor
Authors: Ram Sanjay K. , Kroely Laurent , Bulkin Pavel , Cabarrocas Pere Roca i 
Published: January 2010

AbstractMicrocrystalline silicon films were deposited in a matrix distributed electron cyclotron resonance (MDECR) plasma enhanced chemical vapor deposition (PECVD) system using pure silane, under varying substrate bias conditions. Microstructural characterization of the films shows a lower void fraction and a preponderance of nanograins in films deposited at negative bias, while in positive bias a thin incubation layer is seen with a higher void fraction. Plasma emission studies reveal higher electron temperature and more atomic H at positive bias, which lead to early onset of crystallization. The microstructural properties of the films are correlated with the dark and phototransport properties. Our study demonstrates the importance of substrate bias in controlling the ion energy and properties of films deposited in the MDECR reactor.
The effect of indiscriminate nudging time on large and small scales in regional climate modelling: Application to the Mediterranean basin
Authors: Salameh Tamara , Drobinski Philippe , Dubos Thomas 
Published: January 2010

AbstractA regional climate model (RCM) is driven by the ERA‐40 reanalyses produced by the ECMWF general circulation model (GCM) to simulate the winter 1998 climate over the Mediterranean basin. In this article, we consider the effects on internal variability of temporal nudging. This technique consists of relaxing the RCM's prognostic variables towards the GCM values within a predetermined time‐scale, with the aim of disallowing large and unrealistic departures between driving and driven fields. To interpret the significant effect of time nudging on the regional climate prediction, we develop a ‘toy model’ basically consisting of resolving a linear transport equation with a Newtonian relaxation term. This model predicts the existence of an optimal nudging time which depends on the time‐scale over which numerical errors affect significantly the accuracy of the ‘regional’ solution at the large spatial scales, and the typical time‐scale of the small‐scale phenomena that are not resolved by the GCM. Copyright © 2010 Royal Meteorological Society
Dynamical kernel of the Aladin–NH spectral limited‐area model: Revised formulation and sensitivity experiments
Authors: Bénard P. , Vivoda J. , Mašek J. , Smolíková P. , Yessad K. , Smith Ch. , Brožková R. , Geleyn J.‐F. 
Published: January 2010

AbstractDrawing from the results of theoretical studies about the behaviour of constant‐coefficients semi‐implicit schemes, the dynamical kernel of the Aladin–NH spectral limited‐area numerical weather prediction (NWP) model has been modified in order to allow for a stable and efficient integration of the fully elastic Euler equations. The resulting dynamical kernel offers the possibility to use semi‐Lagrangian transport schemes together with two‐time‐level discretizations at kilometric scales for NWP purposes. The main characteristics of the adiabatic part of the model formulation and the space and time discretization are described in this article. In order to illustrate the dependence of the results on adjustable parameters of the dynamical kernel, some real‐case dynamical‐adaptation forecasts performed with a basic physical parameterization package are presented. The results obtained with this model in real‐case experiments fully confirm the conclusions drawn in previous numerical analysis studies. The good quality of the results is found to be compatible with a routine exploitation in a NWP framework. The Aladin–NH dynamical kernel has been used in the operational NWP ‘AROME’ model since December 2008 at the kilometric scale, with an appropriate physical parameterization package and data assimilation system. Copyright © 2010 Royal Meteorological Society and Crown Copyright.
Natural ventilation effects on temperatures within Stevenson screens
Authors: Harrison R. G. 
Published: January 2010

AbstractThermometer screen properties are poorly characterised at low wind speeds. Temperatures from a large thermometer screen have been compared with those from an automatically shaded open‐air fine‐wire resistance thermometer. For the majority of 5‐minute average measurements obtained between July 2008 and 2009, the screen and fine‐wire temperatures agreed closely, with a median difference <0.05 °C. At low wind speeds however, larger temperature differences occurred. When calm (wind speed at 2 metres, u2, ≤ 0.1 m s−1), the difference between screen and open‐air temperatures varied from −0.25 °C to +0.87 °C. At night with u2 < 0.5 m s−1, this difference was −0.14 °C to 0.39 °C, and, rarely, up to −0.68 °C to 1.38 °C. At the minimum in the daily temperature cycle, the semi‐urban site at Reading had u2 < 1 m s−1 for 52% of the observations 1997–2008, u2 < 0.5 m s−1 for 34% and calm conditions for 20%. Consequently uncertainties in the minimum temperature measurements may arise from poor ventilation, which can propagate through calculations to daily average temperatures. In comparison with the daily minimum temperature, the 0900 UTC synoptic temperature measurement has a much lower abundance (5%) of calm conditions. Copyright © 2010 Royal Meteorological Society
The mixing time of Glauber dynamics for coloring regular trees
Authors: Goldberg Leslie Ann , Jerrum Mark , Karpinski Marek 
Published: January 2010

AbstractWe consider Metropolis Glauber dynamics for sampling proper q‐colorings of the n‐vertex complete b‐ary tree when 3 ≤ q ≤ b/(2lnb). We give both upper and lower bounds on the mixing time. Our upper bound is nO(b/ log b) and our lower bound is nΩ(b/(q log b)), where the constants implicit in the O() and Ω() notation do not depend upon n, q or b. © 2010 Wiley Periodicals, Inc. Random Struct. Alg., 2010
Microelectrochemical investigation on aluminium–steel friction welds
Authors: Schneider M. , Langklotz U. , Michaelis A. , Arnold B. 
Published: January 2010

AbstractAluminium–steel friction welds (AlMgSi0.5/C35 and AlMgSi0.5/X5CrNi18‐10) were electrochemically investigated in a NaAc/HAc buffer (pH 5.9) and 0.1 mol/l NaCl using the microcapillary technique. This technique allows a lateral resolution of electrochemical measurements. However, microscopic investigations and scanning electron microscopy/energy dispersive X‐ray SEM/EDX measurements show that the reaction zone (RZ) and the heat affected zone (HAZ) of the welds are smaller than the microcapillary diameter. This paper discusses the advantages and limitations of the microcapillary technique in view of friction welds. Nevertheless, the electrochemical experiments allow a clear detection of the changing active surface area and the correlation to the microstructure (intermetallics). The application of microcapillary measurements on samples which were exposed in marine climate for 2 years shows a good correlation between the local potential measurements and the local corrosion phenomena. Copyright © 2010 John Wiley & Sons, Ltd.
Structural transformation of silane‐based zirconium‐modified sol–gel coatings
Authors: Collazo A. , Covelo A. , Pérez C. 
Published: January 2010

AbstractThis work is focused on a detailed analysis of silane‐based zirconium‐modified sol–gel coatings and the correlation between thermal treatment and structural transformation. To analyse the influence of the type of silane used, different sols were prepared with 3‐glycidoxypropyltrimethoxysilane (GPTMS), tetraethylortosilicate (TEOS) and tetra‐n‐propoxyzirconium (TPOZ) as precursors. The films were deposited by a dip‐coating procedure on AA2024‐T3 alloy and then submitted to several thermal treatments. Techniques, such as X‐ray photoelectron spectroscopy (XPS), Fourier‐transformed infrared spectroscopy (FTIR) and X‐ray diffraction (XRD), have been used to analyse the structural transformations. The results show that crystallisation of zirconia can be modified by the addition of silanes as co‐precursors, which induces stabilisation of the amorphous state of zirconia and an increase in the critical size for the polymorphic transformation. The type of silane used does not affect the structural transformation of ZrO2. An explanation for the stabilisation of zirconium oxide is proposed. Copyright © 2010 John Wiley & Sons, Ltd.
Estimation of age‐specific incidence rates from cross‐sectional survey data
Authors: Roy Jason , Stewart Walter F. 
Published: January 2010

AbstractAge‐specific disease incidence rates are typically estimated from longitudinal data, where disease‐free subjects are followed over time and incident cases are observed. However, longitudinal studies have substantial cost and time requirements, not to mention other challenges such as loss to follow up. Alternatively, cross‐sectional data can be used to estimate age‐specific incidence rates in a more timely and cost‐effective manner. Such studies rely on self‐report of onset age. Self‐reported onset age is subject to measurement error and bias. In this paper, we use a Bayesian bivariate smoothing approach to estimate age‐specific incidence rates from cross‐sectional survey data. Rates are modeled as a smooth function of age and lag (difference between age and onset age), with larger values of lag effectively down weighted, as they are assumed to be less reliable. We conduct an extensive simulation study to investigate the extent to which measurement error and bias in the reported onset age affects inference using the proposed methods. We use data from a national headache survey to estimate age‐ and gender‐specific migraine incidence rates. Copyright © 2010 John Wiley & Sons, Ltd.
Meta‐regression with partial information on summary trial or patient characteristics
Authors: Hemming K. , Hutton J. L. , Maguire M. G. , Marson A. G. 
Published: January 2010

AbstractWe present a model for meta‐regression in the presence of missing information on some of the study level covariates, obtaining inferences using Bayesian methods. In practice, when confronted with missing covariate data in a meta‐regression, it is common to carry out a complete case or available case analysis. We propose to use the full observed data, modelling the joint density as a factorization of a meta‐regression model and a conditional factorization of the density for the covariates. With the inclusion of several covariates, inter‐relations between these covariates are modelled. Under this joint likelihood‐based approach, it is shown that the lesser assumption of the covariates being Missing At Random is imposed, instead of the more usual Missing Completely At Random (MCAR) assumption. The model is easily programmable in WinBUGS, and we examine, through the analysis of two real data sets, sensitivity and robustness of results to the MCAR assumption. Copyright © 2010 John Wiley & Sons, Ltd.
A simple iterative carrier frequency synchronization technique for OFDMA uplink transmissions
Authors: Sun Pengfei , Zhang Li 
Published: January 2010

AbstractThis paper examines the carrier frequency offset (CFO) estimation problem in the tile‐based orthogonal frequency division multiple access (OFDMA) uplink systems, which is very challenging due to the presence of multiple CFOs. The existing solutions to this problem are either too complex to implement or not flexible in subcarrier allocation. To solve these problems, this paper proposes a tile‐structure based iterative multi‐CFO estimation technique. The proposed method is developed based on a special training sequence with repetitive structure. The inherent multi‐user interference (MUI) compression provided by the tile structure allows us to utilize the repetitive property of the training sequence to jointly estimate the CFOs in the frequency domain with low complexity. Combining the CFO estimation with an interference cancellation scheme and performing iteratively, the algorithm achieves high estimation accuracy and fast convergence. The proposed algorithm is suitable for any subcarrier assignment schemes. In addition, as compared with other existing time domain based algorithms, which achieve the Cramer Rao Bound (CRB) at the price of unaffordable complexity, it closely approaches their performance with over 70% computational saving, which is significantly important for practical implementation. Copyright © 2010 John Wiley & Sons, Ltd.
Distributed spectrum assignment for cognitive networks with heterogeneous spectrum opportunities
Authors: Plummer Anthony , Biswas Subir 
Published: January 2010

AbstractThis paper presents a distributed and localized interference‐aware channel assignment framework for multi‐radio wireless mesh networks in a cognitive network environment. The availability of multiple interfaces and channels in wireless devices is expected to enhance network throughput in wireless mesh networks. A notable design issue in such networks is how to dynamically assign available channels to multiple radio interfaces for maximizing effective network throughput by minimizing interference. The proposed framework uses a novel interference estimation method by utilizing distributed conflict graphs on a per‐interface basis. Presented results obtained via simulation studies in 802.11 based multi‐radio mesh networks indicate that for both homogeneous and heterogeneous primary networks, the proposed protocol can facilitate a large increase in network throughput in comparison with a Common Channel Assignment mechanism that is used as a benchmark in the literature. Copyright © 2010 John Wiley & Sons, Ltd.
Storage correction in cells of patients suffering from mucopolysaccharidoses types IIIA and VII after treatment with genistein and other isoflavones
Authors: Arfi Audrey , Richard Magali , Gandolphe Christelle , Scherman Daniel 
Published: January 2010

AbstractMucopolysaccharidoses are autosomal and recessive lysosomal storage disorders caused by the deficiency of a lysosomal enzyme involved in glycosaminoglycan catabolism. The Sanfilippo type A disease (MPS III A) results from sulfamidase deficiency, which leads to accumulation of heparan sulfate, whereas Sly disease (MPS VII) results from beta‐glucuronidase deficiency, leading to accumulation of heparan, dermatan, and chondroitin sulfates. These syndromes are characterized by severe central nervous system degeneration, resulting in progressive mental retardation, and fatality occurs in severely affected children. To date, no effective treatment is available except for bone marrow transplantation in specific cases. Recently, the use of genistein, an isoflavone that inhibits glycosaminoglycans synthesis, has been tested as substrate reduction therapy for neuronopathic forms of these diseases. We tested five natural analogs to genistein in human fibroblasts from both Sanfilippo A and Sly patients. Four molecules were as efficient as genistein in decreasing glycosaminoglycan accumulation. Moreover, a combination of several isoflavones was more efficient than one single isoflavone, suggesting a synergistic effect. These preliminary data may offer new perspectives for treating Sly and Sanfilippo A diseases and could be relevant to other neurological forms of mucopolysaccharidoses.