bluuebunny/crossref_metadata_2025_split huggingface dataset:
The SST‐forced predictability of the sub‐seasonal mode over East Asia with an atmospheric general circulation model
Authors: Kim Ki‐Young , Kitoh Akio , Ha Kyung‐Ja 
Published: January 2008

AbstractThe sea surface temperature (SST)‐forced predictability in precipitation is investigated in terms of the seasonal mean modes (SMMs) for June–July (JJ) and the sub‐seasonal mode (SSM) using the 24‐year six‐member ensembles simulation with an atmospheric general circulation model (AGCM). The SSM was defined as a 20‐day window length by an extended empirical orthogonal function (EOF) over the East Asian monsoon region. For the JJ mean rainfall, the first EOF of the model ensemble is considered to be the forced SST mode, with being an El Niño Southern Oscillation (ENSO) related pattern from the regressed SST field. The first mode of model was well correlated with the second mode of the observation in the spatial and temporal variation.In the potential predictability, the analysis of variance (ANOVA) was used for the mean mode and the SSM. The potential predictability for the SMM is improved over the north of the 30°N. Compared with JJ mean mode, the SSM has more SST‐forced variance and less internal variability. Copyright © 2008 Royal Meteorological Society
Optical THz‐wave generation with periodically‐inverted GaAs
Authors: Vodopyanov K.L. 
Published: January 2008

AbstractWe overview methods of THz‐wave generation using frequency down‐conversion in GaAs with periodically‐inverted crystalline orientation. First, we compare different nonlinear‐optical materials suitable for THz generation, analyze THz generation process in quasi‐phase‐matched crystals and consider theoretical limits of optical‐to‐THz conversion. Then, we review single‐pass optical rectification experiments with femtosecond pump pulses, performed in periodically‐inverted GaAs, where monochromatic THz output tunable in the range 0.9–3 THz was produced. Finally, we describe a novel approach to create a compact highly efficient tunable (0.5–3.5 THz) room temperature monochromatic THz source, based on the concept of intracavity THz generation via resonantly‐enhanced difference frequency mixing. This approach allowed generating of 1 mW of average THz power, potentially scalable to 10–100 mW.
Modelling human hip joint lubrication subject to walking cycle
Authors: Meziane A. , Bou‐Saïd B. , Tichy John 
Published: January 2008

AbstractThis paper deals with the study of a hip joint prosthesis subject to a walking cycle. Human joints are lubricated by synovial fluid (SF). To properly model joint performance, one must take into account the behaviour of this fluid, which is highly viscoelastic as confirmed in early experimental work. The Phan‐Thien and Tanner (PTT) model is one of the most widely used rheological models. It can properly describe the common characteristics of viscoelastic non‐Newtonian fluids. Based on a microstructural description of the fluid, it is possible to establish laws of rheological behaviour to reproduce shock or the sudden inception of shear, taking into account large deformation and viscoelastic effects. Modelling the geometry of the total hip replacement, the PTT model is applied in spherical coordinates to a thin confined fluid film. Using a modified Reynolds equation developed for this specific geometry, we present a numerical simulation of an artificial hip joint subject to a walking cycle. The equilibrium position depends on the load magnitude and also depends strongly on the load direction. The non‐linear response of the SF leads to some unanticipated complexities. In our case, the dominant effect is the squeeze action between the surfaces. The contact behaviour depends not only on the geometry and kinematics but also on the fluid properties. The minimum film thickness remains higher than likely roughness height during these ‘normal’ conditions. When considering the design of hip joint prostheses, attention should be paid to the rheological properties of SF. Copyright © 2008 John Wiley & Sons, Ltd.
Stimulation of sister chromatid exchanges and mutation by aflatoxin B1‐DNA adducts in Saccharomyces cerevisiae requires MEC1 (ATR), RAD53, and DUN1
Authors: Fasullo Michael , Sun Mingzeng , Egner Patricia 
Published: January 2008

AbstractThe hepatocarcinogen aflatoxin B1 (AFB1) is a potent recombinagen but weak mutagen in the yeast Saccharomyces cerevisiae. AFB1 exposure induces DNA damage‐inducible genes, such as RAD51 and those encoding ribonucleotide reductase (RNR), through a MEC1 (ATR homolog)‐dependent pathway. Previous studies have indicated that MEC1 is required for both AFB1‐associated recombination and mutation, and suggested that AFB1‐DNA adducts are common substrates for recombination and mutagenesis. However, little is known about the downstream effectors of MEC1 required for genotoxic events associated with AFB1 exposure. Here we show that AFB1 exposure increases frequencies of RAD51‐dependent unequal sister chromatid exchange (SCE) and activates Rad53 (CHK2). We found that MEC1, RAD53, and DUN1 are required for both AFB1‐associated mutation and SCE. Deletion of SML1, which encodes an inhibitor of RNR, did not suppress the DUN1‐dependent requirement for AFB1‐associated genetic events, indicating that higher dNTP levels could not suppress the dun1 phenotype. We identified AFB1‐DNA adducts and show that approximately the same number of adducts are obtained in both wild type and rad53 mutants. Since DUN1 is not required for UV‐associated mutation and recombination, these studies define a distinct role for DUN1 in AFB1‐associated mutagenesis and recombination. We speculate that AFB1‐associated DNA adducts stall DNA replication, a consequence of which can either be mutation or recombination. © 2008 Wiley‐Liss, Inc.
HSQC pulse sequences for 19F
Authors: Adams Bruce 
Published: January 2008

AbstractHeteronuclear single quantum coherence (HSQC) sequences using adiabatic (or composite) 180° pulses, suitable for applications requiring wide spectral widths in F2, are described. The sequences can be used with or without multiplicity editing. One variant will work even in the presence of homonuclear couplings that are equal to the heteronuclear 1‐bond coupling. Copyright © 2008 John Wiley & Sons, Ltd.
Simulation of Polymerization and Long Chain Branch Formation in a Semi‐Batch Reactor Using Two Single‐Site Catalysts
Authors: Mehdiabadi Saeid , Soares João B. P. , Dekmezian Armenag H. 
Published: January 2008

AbstractWe developed a mathematical model for the solution polymerization of olefins in a semi‐batch reactor with two single‐site catalysts. In the propylene polymerization case, our objective is to study the production of a thermoplastic elastomer using two catalysts, one capable of forming isotactic chains containing terminal vinyl bonds (macromonomers) and the other producing atactic chains while also being able to copolymerize macromonomers to form long chain branches. A similar thermoplastic elastomer can be produced by polymerizing ethylene and α‐olefin comonomers when the α‐olefin reactivity ratios of the two catalysts are significantly different.magnified image
High Solids Content Waterborne Acrylic/Montmorillonite Nanocomposites by Miniemulsion Polymerization
Authors: Diaconu Gabriela , Paulis Maria , Leiza Jose R. 
Published: January 2008

AbstractWaterborne polymer/clay nanocomposites of methyl methacrylate and butyl acrylate have been prepared by miniemulsion polymerization. Two different commercial organically modified clays have been used: Cloisite 15A and Cloisite 30B. Nanocomposites with partially exfoliated structure, observed by wide‐angle X‐ray diffraction (WAXD), small angle X‐ray scattering (SAXS) and transmission electron microscopy (TEM) were obtained by batch miniemulsion polymerization with 2–4 wt.‐% clay and 30% solids content. The mechanical, thermal and permeation properties of the nanocomposites showed a substantial improvement. Furthermore, this approach has allowed the production of stable and coagulum free latex with solids content up to 42 wt.‐% with partially exfoliated structures.magnified image
VASO‐based calculations of CBV change: Accounting for the dynamic CSF volume
Authors: Scouten A. , Constable R.T. 
Published: January 2008

AbstractThe goal of the vascular space occupancy (VASO) imaging technique is to use selective nulling of the blood signal to infer relative changes in cerebral blood volume (CBV). In accordance with recent work, we show that changes in the local CSF fraction (xc) with activation can significantly impact the VASO signal, thereby limiting our ability to infer ΔCBV from ΔVASO alone. Here we calculate CBV change using a VASO‐based method which ACcounts for the Dynamic Cerebrospinal (ACDC) fluid fraction. By combining data from two separate VASO acquisitions that eliminate either the blood signal (VASOb) or the CSF signal (VASOc), a nonlinear least‐squares optimization may then be used to simultaneously solve for the relative changes in CBV and CSF with activation. The method is applied across the whole brain during a breath‐holding task, offering insight into the relationship between changes in CBV and xc associated with global vasodilatation. Calculations of mean changes in CBV in different volumes of interest obtained from the proposed method compare much better with previous (gold‐standard) PET data than traditional VASO methods that do not account for a nonzero Δxc with activation. This confirms the necessity of incorporating the dynamic CSF volume into VASO‐based calculations of ΔCBV. Magn Reson Med 58:308–315, 2008. © 2008 Wiley‐Liss, Inc.
Noninvasive assessment of myocardial viability in a small animal model: Comparison of MRI, SPECT, and PET
Authors: Thomas Daniel , Bal Harshali , Arkles Jeffrey , Horowitz James , Araujo Luis , Acton Paul D. , Ferrari Victor A. 
Published: January 2008

AbstractAcute myocardial infarction (AMI) research relies increasingly on small animal models and noninvasive imaging methods such as MRI, single‐photon emission computed tomography (SPECT), and positron emission tomography (PET). However, a direct comparison among these techniques for characterization of perfusion, viability, and infarct size is lacking. Rats were studied within 18–24 hr post AMI by MRI (4.7 T) and subsequently (40–48 hr post AMI) by SPECT (99Tc‐MIBI) and micro‐PET (18FDG). A necrosis‐specific MRI contrast agent was used to detect AMI, and a fast low angle shot (FLASH) sequence was used to acquire late enhancement and functional images contemporaneously. Infarcted regions showed late enhancement, whereas corresponding radionuclide images had reduced tracer uptake. MRI most accurately depicted AMI, showing the closest correlation and agreement with triphenyl tetrazolium chloride (TTC), followed by SPECT and PET. In some animals a mismatch of reduced uptake in normal myocardium and relatively increased 18FDG uptake in the infarct border zone precluded conventional quantitative analysis. We performed the first quantitative comparison of MRI, PET, and SPECT for reperfused AMI imaging in a small animal model. MRI was superior to the other modalities, due to its greater spatial resolution and ability to detect necrotic myocardium directly. The observed 18FDG mismatch likely represents variable metabolic conditions between stunned myocardium in the infarct border zone and normal myocardium and supports the use of a standardized glucose load or glucose clamp technique for PET imaging of reperfused AMI in small animals. Magn Reson Med 59:252–259, 2008. © 2008 Wiley‐Liss, Inc.
Incorporating the effects of transcytolemmal water exchange in a reference region model for DCE‐MRI analysis: Theory, simulations, and experimental results
Authors: Yankeelov Thomas E. , Luci Jeffrey J. , DeBusk Laura M. , Lin P. Charles , Gore John C. 
Published: January 2008

AbstractModels have been developed for the analysis of dynamic contrast‐enhanced MRI (DCE‐MRI) data that do not require direct measurements of the arterial input function; such methods are referred to as reference region models. These models typically return estimates of the volume transfer constant (Ktrans) and the extravascular extracellular volume fraction (ve). To date such models have assumed a linear relationship between the measured R1 (≡1/T1) and the concentration of contrast agent, a transformation referred to as the fast exchange limit, but this assumption is not valid for all concentrations of an agent. A theory for DCE‐MRI reference region models which accounts for water exchange is presented, evaluated in simulations, and applied in tumor‐bearing mice. Using reasonable parameter values, simulations show that the assumption of fast exchange can underestimate Ktrans and ve by up to 82% and 46%, respectively. By analyzing a large region of interest and a single voxel the new model can return parameters within approximately ±10% and ±25%, respectively, of their true values. Analysis of experimental data shows that the new approach returns Ktrans and ve values that are up to 90% and 73%, respectively, greater than conventional fast exchange analyses. Magn Reson Med 59:326–335, 2008. © 2008 Wiley‐Liss, Inc.
Sensitivity to change of the Rheumatoid Arthritis Self‐Efficacy scale (RASE) and predictors of change in self‐efficacy
Authors: Hewlett Sarah , Cockshott Zoë , Almeida Celia , Richards Pam , Lowe Rob , Greenwood Rosemary , Kirwan John 
Published: January 2008

AbstractObjectives: Patient education in rheumatoid arthritis (RA) aims to improve health outcomes by prompting people to adopt self‐management behaviours. One precursor for initiating behaviour change is self‐efficacy (SE), a belief that you can do a task. This study tested the sensitivity to change of a new scale to measure SE for self‐management in people with RA, the Rheumatoid Arthritis Self‐Efficacy scale (RASE). Exploratory analysis examined potential predictors of change in SE.Methods: People with RA at 11 rheumatology centres, who had accepted an education programme as part of clinical care, completed questionnaires at baseline, and two and eight weeks after their programme end. Programmes were not standardized, as this was a pragmatic study in clinical practice.Results: A total of 128 patients participated. After controlling for baseline scores, the RASE showed small but significant improvements in SE from baseline (RASE 107.57, CI 105.42‐109.72) to two weeks after programme end (RASE 110.80, CI 108.60‐112.99), and eight weeks (RASE 110.62, CI 108.40‐112.85, p < 0.001). Standardized response means, calculated both by absolute and percentage change, were 0.339 and 0.371 at two weeks after programme end, and 0.321 and 0.352 at eight weeks. Changes in the RASE were associated with behaviour initiation at two and eight weeks (r = 0.419, r = 0.342, p < 0.001). No substantial predictors of change in SE could be identified.Conclusions: The RASE is sensitive to change in a cohort of people with RA in the UK receiving education programmes as routine clinical care. Exploratory analysis did not identify clinical or psychological factors that predict change in SE, suggesting that programmes should not be restricted to particular patients. Copyright © 2008 John Wiley & Sons, Ltd.
Thermally stable and organosoluble binaphthylene‐based poly(urea‐ether‐imide)s: one‐pot preparation and characterization
Authors: Behniafar Hossein , Haghighat Sara 
Published: January 2008

AbstractA new family of wholly aromatic poly(urea‐ether‐imide)s (4a–4f) possessing binaphthylene‐twisted rings was prepared by diphenyl azidophosphate (DPAP)‐activated one‐pot polyaddition reaction of a preformed imide heterocyclic ring‐containing dicarboxylic acid, 2,2′‐bis(4‐trimellitimidophenoxy)‐ 1,1′‐binaphthyl (1) with various kinds of aromatic diamines (3a–3f). At first, with due attention to structural similarity and to compare the characterization data, a model compound 2 was synthesized by the reaction of diimide‐dicarboxylic acid 1 with two mole equivalents of aniline. In this direct method, the polymers were prepared by polyaddition reactions of the in situ‐formed diisocyanate with the aromatic diamines. Molecular weights of the poly(urea‐ether‐imide)s obtained were evaluated viscometrically, and the inherent viscosities (ηinh) measured were in the range 0.10– 0.25 dl/g. All of the polymers were characterized by FT‐IR spectroscopic method and elemental analysis. All of the resulting polymers exhibited an excellent solubility in common polar solvents such as N‐methyl‐2‐pyrrolidone (NMP), dimethyl sulfoxide (DMSO), N,N‐dimethylformamide (DMF), and N,N‐dimethylacetamide (DMAc). Crystallinity of the resulted polymers was evaluated by wide‐angle X‐ray diffraction (WXRD) method, and they exhibited nearly a non‐crystalline nature as evidenced by their diffractograms. The glass transition temperatures (Tg) of the polymers determined by differential scanning calorimetry (DSC) thermograms were in the range of 274–302°C. The temperatures at 10% weight loss (Td10%) from their thermogravimetric analysis (TGA/DTG) curves were found to be in the range of 389–414°C in nitrogen atmosphere. Copyright © 2008 John Wiley & Sons, Ltd.
Gadodiamide contrast agent ‘activates’ fibroblasts: a possible cause of nephrogenic systemic fibrosis
Authors: Edward M , Quinn JA , Mukherjee S , Jensen M‐BV , Jardine AG , Mark PB , Burden AD 
Published: January 2008

AbstractNephrogenic systemic fibrosis (NSF) is a fibrotic disease generating intense interest due to its recent discovery, and unknown cause. It appears confined to patients with renal disease and presents as grossly thickened, indurated, tight skin that is woody to palpation. Histologically, the dermis contains thickened collagen bundles, numerous plump fibroblast‐like cells, and elevated hyaluronan expression. Recent data suggest a link between the use of gadolinium chelate as an MRI contrast agent and the onset of the disease. Fibroblasts from the lesions of six NSF patients, all of whom were exposed to gadodiamide, were compared with control fibroblasts for hyaluronan and collagen synthesis. Serum from NSF patients was assessed for fibroblast hyaluronan‐stimulating activity, collagen synthesis, and gadodiamide for its effect on fibroblast proliferation and matrix synthesis. NSF fibroblasts synthesized excess levels of hyaluronan and collagen compared with control fibroblasts, with up to 2.8‐fold and 3.3‐fold increases, respectively. NSF patient serum stimulated control fibroblast hyaluronan synthesis by up to 7‐fold, and collagen synthesis by up to 2.4‐fold. 1 mM gadodiamide added to culture medium stimulated fibroblast growth in a dose‐dependent manner, decreasing their doubling time from 28 h to 22 h, and increasing the maximum cell density. Even a short exposure to gadodiamide stimulated cell growth, suggesting that the cells were activated by the gadodiamide. The growth of fibroblasts within contracted collagen lattices was also significantly stimulated by gadodiamide, while fibroblasts exposed to gadodiamide synthesized increased levels of hyaluronan. Control fibroblasts exposed to gadodiamide, and NSF fibroblasts exhibited an extensive pericellular coat of hyaluronan, and expressed α‐smooth muscle actin. Gadolinium chloride did not affect fibroblast growth. This report demonstrates that NSF fibroblasts synthesize excess levels of hyaluronan and collagen, and that gadodiamide stimulates control fibroblast growth, matrix synthesis, and differentiation into myofibroblasts, suggesting a possible role for gadodiamide in the pathophysiology of NSF. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Expression of pentraxin 3 (PTX3) in human atherosclerotic lesions
Authors: Savchenko AS , Imamura M , Ohashi R , Jiang S , Kawasaki T , Hasegawa G , Emura I , Iwanari H , Sagara M , Tanaka T , Hamakubo T , Kodama T , Naito M 
Published: January 2008

AbstractPentraxin 3 (PTX3) and C‐reactive protein (CRP) are members of the pentraxin superfamily. PTX3 expression is induced in response to inflammatory signals, and is produced at sites of inflammation by several types of cell, primarily monocytes/macrophages, dendritic cells (DCs), endothelial cells, smooth muscle cells (SMCs), and fibroblasts, but is not produced by hepatocytes, which are a major source of CRP. The aim of our study was to investigate the expression pattern of PTX3 in human atherosclerotic lesions using a novel monoclonal antibody against PTX3. We examined coronary arterial thrombi containing an atherosclerotic plaque component removed from patients with acute myocardial infarction and human aortic tissues with various degrees of atherosclerosis sampled from autopsy cases. Immunohistochemical study of paraffin and frozen sections indicated that macrophages, mainly foam cells, expressed PTX3 in advanced atherosclerotic lesions. Interestingly, we also clearly observed PTX3‐positive neutrophils infiltrating into atherosclerotic plaques, suggesting that PTX3 derived from neutrophils as well as macrophages plays an important role in atherogenesis. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Solar power generation using high altitude platforms feasibility and viability
Authors: Aglietti G. S. , Markvart T. , Tatnall A. R. , Walker S. J. 
Published: January 2008

AbstractThis paper investigates the feasibility and economical advantages that could be offered by a new facility for the production of solar energy. The basic concept is to exploit a high altitude aerostatic platform to support Photovoltaic (PV) modules to substantially increase their output by virtue of the significantly enhanced solar radiation at the operating altitude of the aerostat. The electric energy is then transmitted to the ground using the aerostat mooring cable. The technical feasibility of the concept is demonstrated by using standard equations and realistic values for the relevant engineering parameters that describe the technical properties of the materials and subsystems. There are, nevertheless, issues to be addressed to improve the performance; however, none of these issues is deemed to negate the technical feasibility of this concept. A preliminary cost model is illustrated and using unit cost data for the various materials and subsystems it is shown that it is possible to identify a specific size that minimizes the cost of energy produced. This cost could be considerably lower than what can be achieved by solar panels based on the ground in the UK. Copyright © 2008 John Wiley & Sons, Ltd.
Recent excursions to the borderlands between the realms of concerted and stepwise: carbocation cascades in natural products biosynthesis
Authors: Tantillo Dean J. 
Published: January 2008

AbstractRecent theoretical studies on concerted carbocation rearrangements that involve multiple asynchronous chemical events are described. The relevance of such rearrangements to natural products biosynthesis is highlighted. Copyright © 2008 John Wiley & Sons, Ltd.
Short‐circuit current improvement of CuGaSe2 solar cells with a ZnS/(Zn,Mg)O buffer combination
Authors: Witte Wolfram , Hariskos Dimitrios , Kniese Robert , Powalla Michael 
Published: January 2008

AbstractCuGaSe2 (CGS) thin‐film solar cells were prepared with an in‐line co‐evaporation process and the established buffer combination CdS/i‐ZnO was replaced by ZnS/(Zn,Mg)O. We obtained functional CGS solar cells with a strong gain in the short‐circuit current density as compared to the CdS/i‐ZnO buffer reference cells. The enhanced current density is a result of improved transmission in the wavelength region between 330 nm and 550 nm of the ZnS/(Zn,Mg)O buffer combination as compared to CdS/i‐ZnO. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)