bluuebunny/crossref_metadata_2025_split huggingface dataset:
Young age a predictor of weak reactivity in a rapid antibody test in infants infected with HIV
Authors: Maree Leana , van Zyl Gert U. , Lotter Shelley L. , de Beer Corena , Esser Monika M. , Preiser Wolfgang 
Published: June 2010

AbstractIn a resource‐constrained African setting, children suspected of being infected with HIV are often screened with rapid antibody tests prior to definitive diagnosis with viral genome detection. It has previously been shown that a rapid antibody assay such as the Capillus™ HIV‐1/HIV‐2 test may have a high false‐negative rate in infants. In this study CD count and percentage, HIV‐1 viral load, antigen‐specific reactivity, and age was explored as predictors of negative or low antibody reactivity by this assay. Young age was found to be the only factor associated significantly with low antibody reactivity. This phenomenon appeared to be specific to HIV since no such age association was found for antibody reactivity to tetanus toxoid. Rapid assays only validated in adults should therefore be used with utmost caution in young infants since this may lead to high rates of false‐negative results. J. Med. Virol. 82:1314–1317, 2010. © 2010 Wiley‐Liss, Inc.
Modelling climate and the nature of climate models: A review
Authors: Shine K. P. , Henderson‐Sellers A. 
Published: June 2010

AbstractA new structural framework for climate models is presented. Four basic model types are discussed: general circulation models, energy balance models, one dimensional radiative convective models and two dimensional zonally averaged dynamical models. The fundamental importance of three primary processes in the climate system‐radiation, dynamics and surface processes‐is underlined and the degree to which each of these mechanisms is incorporated in each model is highlighted.
Dopamine transporter single photon emission computerized tomography in the diagnosis of dementia with Lewy bodies
Authors: Walker Rodney W.H. , Walker Zuzana 
Published: June 2010

AbstractDementia with Lewy bodies (DLB) is part of the spectrum of Lewy body disorders. However, it may be difficult to diagnose patients who have dementia but no Parkinsonism. Visual and semiquantitative assessment of the nigrostriatal dopaminergic nerve terminals in the putamen and caudate nuclei can be obtained with single photon emission computerized tomography (SPECT) using ligands that bind to the dopamine transporter molecule in the membranes of the nigrostriatal nerve terminals. This can be employed as a means of identifying subclinical degeneration of nigrostriatal neurones in patients with suspected DLB, increasing the probability of the diagnosis. In several studies, the sensitivity and specificity of abnormal dopamine transporter scans with regard to diagnosing probable DLB are better than 75 and 90%, respectively. This communication outlines the evidence for this and discusses some of the advantages, potential disadvantages, and areas of uncertainty with regard to the use of dopamine transporter SPECT in DLB diagnosis. © 2009 Movement Disorder Society
Absolute MR thermometry using time‐domain analysis of multi‐gradient‐echo magnitude images
Authors: Sprinkhuizen Sara M. , Bakker Chris J. G. , Bartels Lambertus W. 
Published: June 2010

AbstractMRI allows for absolute temperature measurements in substances containing two spectral resonances of which the frequency difference Δf(T) is related to absolute temperature. This frequency difference can be extracted from spectroscopic data. An image‐based MR technique that allows for the acquisition of spectroscopic data at high temporal and spatial resolution is the multi‐gradient‐echo sequence. In this work, the application of the multi‐gradient‐echo sequence for MR thermometry purposes was further developed. We investigated the possibility of postprocessing the multi‐gradient‐echo data into absolute temperature maps, using time‐domain analysis of the magnitude of the multi‐gradient‐echo signals. In this approach, instead of an indirect computation of Δf(T) from separately found frequencies, Δf(T) is a direct output parameter. In vitro experiments were performed to provide proof of concept for retrieving absolute temperature maps from the time‐domain analysis of multi‐gradient‐echo magnitude images. It is shown that this technique is insensitive to both field drift and local field disturbances. Furthermore, ex vivo bone marrow experiments were performed, using the fat resonance as a reference for absolute temperature mapping. It is shown that the postprocessing based on the magnitude signal in the time domain allows for the determination of Δf(T) in bone marrow. Magn Reson Med 64:239–248, 2010. © 2010 Wiley‐Liss, Inc.
Nanocomposites of a bismaleimide resin with octaphenylsilsesquioxane or nano‐SiO2
Authors: Huang Fuwei , Huang Farong , Zhou Yan , Du Lei 
Published: June 2010

AbstractNanocomposites were prepared from the resin of 4,4′‐bismaleimido‐diphenylmethane (BDM) with dipropargyl ethers of hexafluorobisphenol A (DPBPF) and octaphenylsilsesquioxane (OPS) or nano‐SiO2. The nanocomposites were characterized by Fourier transform infrared spectroscopy, scanning electron microscope, dynamic mechanical analysis and thermogravimetric analysis. The results exhibited that OPS or nano‐SiO2 particles could be easily dispersed in the nanocomposites and the glass transition and decomposition temperatures of c‐BDM‐DPBPF‐OPS and c‐BDM‐DPBPF‐SiO2 nanocomposites were higher than those of c‐BDM‐DPBPF resin. The reinforcement of OPS was more effective than that of nano‐SiO2 in the nanocomposites. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers
An efficient strategy based on MAE, HPLC‐DAD‐ESI‐MS/MS and 2D‐prep‐HPLC‐DAD for the rapid extraction, separation, identification and purification of five active coumarin components from radix angelicae dahuricae
Authors: Xie Ying , Zhao Weiquan , Zhou Tingting , Fan Guorong , Wu Yutian 
Published: June 2010

AbstractIntroduction – Further studies of active coumarin components in Radix Angelicae Dahuricae (AE) are absolutely essential to provide data on pharmacology, toxicology and quality for innovative drug candidates. Thus, the preparation of active component standards and the administration of coumarin monomers should be carried out. The isolation of the low‐level active components from complex Traditional Chinese Medicine (TCM) samples necessitates the development of rapid, simple and economical modern extraction, separation, identification and purification methods.Objective – To develop an efficient strategy for the rapid extraction, separation, identification and purification of coumarins from AE.Methodology – First, active coumarins in AE were extracted with microwave‐assisted extraction (MAE) after the extraction conditions were optimised. Second, gradient extraction methods with MAE were used to partially purify AE. Third, a high‐performance liquid chromatography–diode array detection‐electrospray ionisation tandem mass spectrometry (HPLC‐DAD‐ESI‐MS/MS) method was applied for the preliminary on‐line identification and screening of the main coumarins in AE extract. Finally, a two‐dimensional preparative high‐performance liquid chromatography–diode array detection (2D‐prep‐HPLC‐DAD) system was developed for further preparative separation of those target components.Results – Altogether 10 coumarins have been identified and five of them including xanthotoxol, osthenol, oxypeucedanin hydrate, byakangelicin and imperatorin were deemed as target components for the preparative isolation. All of the five isolated coumarins were at high purities of over 99% and the production rate was much higher than the traditional methods.Conclusion – The present paper demonstrates that these consecutive approaches are very useful for to isolate chemical constituents from TCM.
Optimisation of a microwave‐assisted method for extracting withaferin A from Withania somnifera Dunal. using central composite design
Authors: Mirzajani Fateme , Ghassempour Alireza , Jalali‐Heravi Mehdi , Mirjalili Mohammad Hossein 
Published: June 2010

AbstractIntroduction – Recently, there have been growing attention on the modification and optimisation of new extraction and quantification methods, caused by the lack of environmentally friendly methodologies for the extraction of phytochemicals from complex matrices. In the case of pharmaceutical compounds, not only the extraction procedure but also the analysis method should be efficient, precise, fast and easy.Objectives – The essential pharmaceutical characteristics and trace concentration of withanolides led us to modify and optimise the previously reported extraction and quantification procedure for withaferin A (WA) as a candidate for withanolides.Matrial and methods – The WA from the air‐dried aerial part of Withania somnifera Dunal. was extracted using a microwave‐assisted extraction (MAE) technique. Four variables affecting the extraction procedure were optimised using the central composite design approach. The method of high‐performance thin‐layer chromatography assay was validated and applied for the quantification of each experiment.Results – The optimum values of factors were: extraction time (150 s), extraction temperature (68°C) and 17 mL of methanol : water in the ratio 25 : 75 as extracting solvent. The solvent system consisted of ethyl acetate : toluene : formic acid : 2‐propanol (7.0 : 2.0 : 0.5 : 0.5, v/v/v/v), and densitometric scanning at 220 nm was applied for the analysis. The dynamic linear range, LOD, LOQ and recovery with the inter‐day, and intra‐day RSDs of the developed method indicated the validity of the method.Conclusion – A pressurised MAE method for extracting WA from the plant's aerial part was optimised using factorial‐based design. The net effect of time, temperature, solvent volume and its ratio suggests that the yield of WA increases until each factor reaches its optimum value, and decreases with further increase in temperature or solvent ratio. Copyright © 2010 John Wiley & Sons, Ltd.
Characterisation of two South American food and medicinal plants by chemometric methods based on their multielemental composition
Authors: Cantarelli Miguel A. , Pellerano Roberto G. , Del Vitto Luis A. , Marchevsky Eduardo J. , Camiña José M. 
Published: June 2010

AbstractIntroduction – The chemometric characterisation of two plants frequently used as food and medicinal species, Achyrocline satureioides and Achyrocline venosa (Asteraceae: Gnaphalieae), was carried out based on their mineral composition. Both species, known by the common name of ‘marcelas’, are very similar in their morphological features but they have different medicinal and food properties.Objective – To develop multivariate models for the classification of A. satureiodes and A. venosa based on their mineral content.Methodology – The analytic determinations were made by means of inductively coupled plasma optical emission spectrometry from aerial parts of the plants. An internal standard was used to evaluate the accuracy in the sample treatment and the recovery of toxic elements was studied. The multivariate methods used include principal components analysis, cluster analysis and linear discriminant analysis.Results – Classification for both A. satureioides and A. venosa was successful in all cases using only four variables: aluminium, iron, magnesium and sulphur content. The concentrations of the following elements were determined: Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, La, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sr, Ti, V, Y and Zn.Conclusions – This method is useful to identify both species in raw material in order to detect eventual errors of selection. Copyright © 2010 John Wiley & Sons, Ltd.
Rapid validated HPTLC method for estimation of betulinic acid in Nelumbo nucifera (Nymphaeaceae) rhizome extract
Authors: Mukherjee Debajyoti , Kumar N. Satheesh , Khatua Taraknath , Mukherjee Pulok K. 
Published: June 2010

AbstractIntroduction – Betulinic acid (pentacyclic triterpenoid) is an important marker component present in Nelumbo nucifera Gaertn. rhizome. N. nucifera rhizome has several medicinal uses including hypoglycaemic, antidiarrhoeal, antimicrobial, diuretic, antipyretic, psychopharmacological activities.Objective – To establish a simple, sensitive, reliable, rapid and validated high‐performance thin‐layer chromatography method for estimation of betulinic acid in hydro‐alcoholic extract of N. nucifera Gaertn. rhizome.Materials and methods – The separation was carried out on a thin‐layer chromatography aluminium plate pre‐coated with silica gel 60F254, eluted with chloroform, methanol and formic acid (49 : 1 : 1 v/v). Post chromatographic derivatisation was done with anisaldehyde–sulphuric acid reagent and densitometric scanning was performed using a Camag TLC scanner III, at 420 nm.Results – The system was found to produce a compact spot for betulinic acid (Rf = 0.30). A good linear precision relationship between the concentrations (2–10 µg) and peak areas were obtained with the correlation coefficient (r) of 0.99698. The limit of detection and limit of quantification of betulinic acid were detected to be 0.4 and 2.30 µg per spot. The percentage of recovery was found to be 98.36%. The percentage relative standard deviations of intra‐day and inter‐day precisions were 0.82–0.394 and 0.85–0.341, respectively.Conclusion – This validated HPTLC method provides a new and powerful approach to estimate betulinic acid as phytomarker in the extract. Copyright © 2010 John Wiley & Sons, Ltd.
Ultrasound screening for fetal aneuploidy using soft markers in the overweight and obese gravida
Authors: Tsai Lily J. , Ho Monique , Pressman Eva K. , Thornburg Loralei L. 
Published: June 2010

AbstractObjectiveTo determine the completion rate of ultrasound surveys for aneuploidy markers by maternal body mass index (BMI).MethodsA retrospective review of ultrasounds on midtrimester singleton pregnancies was performed. Subjects were grouped as normal, overweight (BMI 25–29.9 kg/m2), and obese: class I (30–34.9 kg/m2), class II (35–39.9 kg/m2), and class III (≥ 40 kg/m2). Examinations with visualization of at least seven of eight markers were considered complete.ResultsOf 14 353 ultrasounds reviewed, 5690 patients were eligible: 43% normal, 29% overweight, 27% obese. Completion rates differed significantly between groups (64% normal, 64% overweight, 61% class I, 55% class II, 47% class III, p < 0.001). The screen positive rates (≥1 marker) differed significantly overall (16% normal, 13% overweight, 15% class I, 12% class II, 10% class III, p < 0.02), but not for complete examinations (p = 0.42).ConclusionsSince completion rates for ultrasound aneuploidy screening are inversely related to maternal obesity, obese women are underscreened. Copyright © 2010 John Wiley & Sons, Ltd.
Determination of the complex linear electro‐optic coefficient of GaAs and InP
Authors: Pristovsek Markus 
Published: June 2010

AbstractThe complex linear electro‐optic coefficient d41 was determined for the first time above the fundamental band gap of GaAs and InP by measuring the doping induced band bending of several oxidized samples in reflectance anisotropy spectroscopy. From the real and imaginary part of the change of the spectra for different carrier concentrations the spectral change of d41 was calculated. This is the first determination of the imaginary part ${\rm Im}\,(d_{41} )$.
Chemical nature of N‐ions incorporated into epitaxial ZnO films
Authors: Hoffmann Patrick , Pettenkofer Christian 
Published: June 2010

AbstractEfficient p‐type doping of zinc oxide (ZnO) is hindered on the one hand by the strong native n‐type doping of the ZnO, on the other hand, compensation effects (defect generation due to p‐doping) tend to preserve the n‐type doping. Incorporation of nitrogen is proposed as a promising method to achieve p‐type ZnO, because the ionic radii of nitrogen and oxygen are comparable. Therefore, nitrogen atoms can replace oxygen. Nevertheless, a reliable and stable p‐doping is still an unmatched challenge. This work will focus on the chemical nature of nitrogen implanted by ion irradiation into metal‐organic MBE grown ZnO layers on sapphire substrate. The incorporated nitrogen was investigated by photoelectron spectroscopy using synchrotron radiation (PES) and monochromatised Al Kα (mXPS), and near edge X‐ray absorption spectroscopy (NEXAFS). The preparation conditions were varied for preferential incorporation of the different nitrogen species. The three main N1s‐PES components were assigned to different nitrogen compounds (molecular N2, NO bonds and NZn bonds) with the help of NEXAFS data. In addition, the thermal stability of the nitrogen compounds were investigated. These results may lead to an optimisation of the nitrogen implantation process for a better doping efficiency.
Modelling precipitation in frontal rainbands
Authors: Cox G. P. 
Published: June 2010

AbstractThe main aim of this study is to establish the ability of a simple parametrization to represent adequately the microphysical processes acting in frontal rainbands. In order to do this we compare it with a more detailed parametrization in conditions typical of warm frontal and narrow cold frontal rainbands. Simulations using a 2‐dimensional diagnostic model indicate that a mixed phase parametrization is required in dynamical models of high resolution.
The adjustment of numerical weather prediction models to local perturbations
Authors: Barwell B. R. , Bromley R. A. 
Published: June 2010

AbstractThe linearized two‐dimensional equations of motion of an f plane are solved for a localized perturbation using local polar coordinates, and a general solution involving Bessel functions is found which can be fitted to any initial conditions. Three types of perturbation are used as examples; they show the formation of an external gravity wave which propagates outward leaving a geostrophically balanced residual flow as t→x. The divergent component of the initial wind field has no effect on this residual flow. Experiments in which the same perturbations were applied to all levels of a numerical model showed good agreement with the analytical solutions.Using an isentropic temperature profile as an example, the theory is extended to three‐dimensional perturbations. As well as the gravity waves and geostrophic residual flow found in two dimensions, a third component of the solution is found, namely, an inertial oscillation originating in the deviation of the wind perturbation from its vertical mean. This oscillation continues indefinitely with the Coriolis frequency. Numerical model experiments show good agreement with the solutions in the early stages of adjustment though the inertial oscillation slowly decays through internal gravity wave generation.Finally, the analytical solutions are discussed in the light of the results of research on the design and performance of analysis schemes.
Medium and extended range predictability and stability of the Pacific/North American mode
Authors: Palmer T. N. 
Published: June 2010

AbstractIt is shown from an assessment of a small set of extended range forecasts from two centres, and from a much larger set of medium range forecasts from one centre, that variability in predictive skill is strongly related to fluctuations in the Pacific/North American (PNA) mode of low frequency variability. A hypothesis is put forward that this is associated with the dependence of large‐scale instability of the forecast flow on the amplitude of the PNA mode. The hypothesis is tested in a barotropic model using as basic states, composite skilful and unskilful cases from the set of medium range forecasts and individual monthly mean fields. Results from the barotropic stability analysis suggests possible reasons for the asymmetric nature of the response of general circulation models to sea surface temperature anomalies of opposite sign, relevant to forecasting on monthly to seasonal timescales. Observational evidence for the stability hypothesis is also discussed.
Air parcel thermodynamic properties and aerosol particle concentrations in the maritime atmospheric boundary layer
Authors: Smith M. H. 
Published: June 2010

AbstractIn some circumstances, the distribution of particles in the maritime atmosphere may be simply related to the atmospheric profile. For data obtained in the Outer Hebrides in 1982 by the Meteorological Office Research Flight aircraft, a strong correlation is found between particle concentrations over the radius range from 0.25 to 4m̈m and the thermodynamic properties of air parcels at various levels within the marine atmospheric boundary layer. This approach offers a potential tool toward better understanding of particle distribution and provides a means for estimating particle concentrations at various levels on the basis of a standard meteorological sounding.
Digital imaging for scanning electron microscopy
Authors: Postek Michael T. , Vladár András E. 
Published: June 2010

AbstractThe development and application of digital imaging technology has been one of the major advancements in scanning electron microscopy (SEM) during the past several years. This digital revolution has been brought about by significant progress in semiconductor technology, notably the availability of less expensive, high‐density memory chips and the development of inexpensive, high‐speed, analog‐to‐digital and digital‐to‐analog converters, mass storage, and high‐performance central processing units. This paper reviews a number of the advantages presented by digital imaging as applied to the SEM and describes a system developed at the National Institute of Standards and Technology for this purpose.
A fast‐scanning optical microscope for imaging magnetic domain structures
Authors: Ping G. L. , See C. W. , Somekh M. G. , Suddendorf M. B. , Vincent J. H. , Footner P. K. 
Published: June 2010

AbstractThis paper describes a fast‐scanning Kerr microscope which produces quantitative and repeatable images with a scan rate of one frame/s. The rapid scan facility results in a practical system for routine examination of magnetic samples, whereas presently available scanning and full‐field systems are relatively slow.
Design and characterisation of a single‐reflection, solid‐state detector with high discrimination against backscattered electrons for cathodoluminescence microscopy
Authors: Pey K. L. , Phang J. C. H. , Chan D. S. H. , Leong Y. K. 
Published: June 2010

AbstractAportable solid‐state detector (SSD) for cathodoluminescence (CL) has been constructed and tested. The detector geometry utilises a parabolic reflector to direct light towards the solid‐state detection element. The photo‐sensitive area of the solid‐state photodiodes is situated at a level in line with or sightly below the top surface of the specimen to minimise the collection of backscattered electrons (BSEs) coming directly from the beam impact point. The components have been integrated into a single unit to enhance portability. In comparison with a commercial CL detection system, the new geometry shows excellent efficiency in rejecting BSE contribution during CL operation. A light collection solid angle close to 1.97π steradian is realised in this geometry, higher than other SSD‐CL systems. A method for characterising CL detection system performance has been developed.