bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on the shear viscosity behavior of keratin/PEO blends for nanofibre electrospinning
Authors: Varesano Alessio , Aluigi Annalisa , Vineis Claudia , Tonin Claudio 
Published: May 2008

AbstractGraessley's theory has been applied to keratin/PEO concentrated aqueous solutions giving qualitative insight to the rheology of these polymer blends in electrospinning. The shear rate dependent viscosity of different blends was compared with that of pure polymer solutions. The characteristic time τη was calculated by the minimum value of $ \dot \gamma $ at the beginning of the non‐Newtonian viscosity behavior. Flow curves of PEO (at concentration from 1.0 to 7.0 wt %) reduce to a single curve by plotting η/η0 against $ \dot \gamma{\tau_\eta} $. Moreover, PEO solutions exhibit a linear proportionality between zero‐shear viscosity and the characteristic time η0 ∝ τη. Keratin/PEO blend solutions follow the same proportionality at very high and low keratin content, whereas linearity drops when the keratin content range from 50 to 70%. The departure from the theory has been interpreted as a sign of some interaction between the macromolecules of keratin and PEO. It was supposed that keratin displaces solvent molecules and expands the PEO chain coils increasing the relaxation time of the polymer solution. This behavior was correlated with changes in the morphology of the nanofibres produced by electrospinning from these polymer blends. Finally, additive rules to zero‐shear viscosity were applied to keratin and PEO solutions, indicating that the experimental η0 values were higher than the theoretical ones for all the proportions of the blends, especially for high keratin amount. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1193–1201, 2008
Preparation and characterization of vinylidene chloride‐co‐vinyl chloride copolymer/fluorinated synthetic mica nanocomposites I thermal and mechanical properties studies
Authors: Hsieh Tar‐Hwa , Huang Jan‐Kuan , Ho Ko‐Shan , Bi Xiaotao , Ho Tsung‐Han , Yang Shin‐Shiao , Chang Yu‐Chen 
Published: May 2008

AbstractPoly(vinylidene chloride‐co‐vinylchloride)/organically modified fluorinated synthetic mica (MEE) (VDC‐VC/MEE) nanocomposites were prepared by melt blending of VDC‐VC copolymer with MEE, in the presence of dioctyl phthalate (DOP) which acted as a plasticizer and a cointercalating agent. The nanostructure, thermal, and dynamic mechanical properties of the VDC‐VC/MEE nanocomposites were studied by wide angle X‐ray diffractometer (WAXD), scanning electron microscope (SEM), transmission electron microscope (TEM), thermogravimetric analyzer (TGA), and dynamic mechanical analyzer (DMA). It was found that partially intercalated and partially exfoliated structures coexisted in VDC‐VC/MEE nanocomposities. Below 8 wt % MEE content, the intercalation effect of nanocomposites decreased with increasing the MEE content. Under a nitrogen atmosphere, VDC‐VC/MEE nanocomposites exhibited a single step thermal degradation behavior. The nanostructure of VDC‐VC/MEE can effectively prevent volatile gases from being released, and thus enhances its thermal stability. The thermal stability of VDC‐VC/MEE nanocomposites is strongly related to the morphology of nanocomposites and the degraded composites structure. DMA revealed a significant improvement in the storage modulus within the testing temperature range. The increase in storage modulus depends on the MEE content, which is attributed to the dispersed phase morphology. The glass transition temperature of VDC‐VC/MEE nanocomposites is affected by the chain mobility in the nanocomposites rather than the aggregative morphology. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1214–1225, 2008
Morphology and properties of cyanate ester/liquid polyurethane/silica nanocomposites
Authors: Zhang Qi‐Lu , Ma Xiao‐Yan , Liang Guo‐Zheng , Qu Xiao‐Hong , Huang Yun , Wang Shu‐Hui , Kou Kai‐Chang 
Published: May 2008

AbstractThe high‐speed homogeneous shearing method was applied to prepare nanocomposites of cyanate ester (CE) with liquid polyurethane elastomer (PUR) and silica. To investigate the influence of various components on the morphology and properties of the ternary composites, the binary composites of CE/PUR and CE/silica were also involved in this article. The morphology of the cured materials of binary and ternary systems was investigated by transmission electron microscopy (TEM), and the results show that silica nanoparticles were uniformly distributed in the ternary and binary matrix. Phase separation of elastomer in composites was not observed by TEM. FTIR test and dynamic mechanical analysis (DMA) proved that chemical linking was existent between PUR and CE. Scanning electron microscopy examinations and mechanical properties tests were carried out. The results show that ternary composites displayed higher fracture toughness and impact strength compared with most of the binary systems. This suggests that the addition of PUR and nanosilica can synergistically improve the toughness of CE. DMA studies confirmed that the incorporation of silica can increase the storage modulus and Tg for CE and CE/PUR system, since there are a good adhesion and a strong hydrogen bonding between silica and polymers. The thermal property of ternary composites increases with the increase of silica nanoparticle loading. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1243–1251, 2008
Layer‐by‐layer assembly of gelatin
Authors: Lin Yuan , Su Zhaohui 
Published: May 2008

AbstractElectrostatic assembly of one species can be realized using gelatin as a polyampholyte. Under suitable conditions where the electrostatic attraction and repulsion were both significant and in balance, linear growth of multilayers driven by electrostatic interactions was sustained over many successive assembly steps, and the maximum amount of adsorption of each layer was reached when the solution pH was around the isoelectric point. The rearrangement of the adsorbed chains after drying was confirmed by contact angle analysis. In addition with only one species involved, the assembled thin films should be chemically uniform rather than layered. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1252–1257, 2008
Amyotrophic lateral sclerosis: Protein chaperone dysfunction revealed by proteomic studies of animal models
Authors: Jain Mohit Raja , Ge Wei‐wen , Elkabes Stella , Li Hong 
Published: May 2008

AbstractAmyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that affects motor neurons and causes progressive muscle weakness and atrophy. The etiology and pathogenesis of ALS are largely unknown and no effective treatment is presently available. About 10% of patients have the familial or inherited form of the disease (fALS), among which 20% is linked to mutations with Cu2+/Zn2+ superoxide dismutase (mSOD1). Transgenic animals expressing human mSOD1 are excellent models for understanding not only fALS but sporadic ALS as well. Pathological features in both ALS patients and mSOD1 transgenic animals' spinal cords share commonalties including the accumulation of misfolded protein inclusions. Recent proteomic investigations on ALS animal models have discovered alterations in protein expression, protein‐protein interactions and post‐translational modifications. These efforts have revealed aspects of potential pathogenic mechanisms and identified probable therapeutic targets. The present review summarizes the major findings of proteomics studies performed on the mSOD1 mice with particular emphasis on the spinal cord proteome. These results are compared with those reported using cell cultures or specimens obtained from ALS patients. The convergence of pathogenic processes on protein chaperone function, and its relationship to protein degradation, metabolic dysfunction and oxidative signaling events is discussed.
Proteomics‐based investigations of animal models of disease
Authors: Bousette Nicolas , Gramolini Anthony O. , Kislinger Thomas 
Published: May 2008

AbstractCells contain a large yet, constant genome, which contains all the coding information necessary to sustain cellular physiology. However, proteins are the end products of genes, and hence dictate the phenotype of cells and tissues. Therefore, proteomics can provide key information for the elucidation of physiological and pathophysiological mechanisms by identifying the protein profile from cells and tissues. The relatively novel techniques used for the study of proteomics thus have the potential to improve diagnostic, prognostic, as well as therapeutic avenues. In this review, we first discuss the benefits of animal models over the use of human samples for the proteomic analysis of human disease. Next, we aim to demonstrate the potential of proteomics in the elucidation of disease mechanisms that may not be possible by other conventional technologies. Following this, we describe the use of proteomics for the analysis of PTM and protein interactions in animal models and their relevance to the study of human disease. Finally, we discuss the development of clinical biomarkers for the early diagnosis of disease via proteomic analysis of animal models. We also discuss the development of standard proteomes and relate how this data will benefit future proteomic research. A comprehensive review of all animal models used in conjunction with proteomics is beyond the scope of this manuscript. Therefore, we aimed to cover a large breadth of topics, which together, demonstrate the potential of proteomics as a powerful tool in biomedical research.
Study of environmental degradation of silver surface
Authors: Águas H. , Silva R. J. C. , Viegas M. , Pereira L. , Fortunato E. , Martins R. 
Published: May 2008

AbstractTo evaluate the evolution of a dark film formation on silver surface objects, several coupons were catalogued and place inside a museum, located in an urban area. The changes on these samples were measured by spectroscopic ellipsometry, in periods of months. This technique allows the reduction of the coupons exposure time, in several months, due to its high sensitivity to surface modifications, with acceptable results for the evaluation of its degradation. The thicknesses of the degradation layers and the optical properties of silver oxide, chloride and sulphide reference samples were determined using a mixture of Tauc‐Lorentz and Drude models. The composition of the silver corrosion layer was determined by fitting the layer using a Bruggeman Effective Medium Approximation (BEMA) of the three products plus voids. It was found that the thickness of the layer depends in the placement of the coupons, namely, inside or outside displayers. The average film thickness after 6 months was of 180 Å and 280 Å, inside and outside the displayers, respectively. The main compounds found in the layers were the silver chlorides and sulphides, which composition changed with the thickness of the layer, and the exposition time. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A numerical procedure for combined many‐body‐QED calculations
Authors: Lindgren Ingvar , Salomonson Sten , Hedendahl Daniel 
Published: May 2008

AbstractA procedure for relativistically covariant many‐body perturbation theory (MBPT) has been developed, and some numerical implementation has been started. The procedure is based upon the previously introduced covariant evolution operator, which is a field‐theoretical concept, closely related to MBPT. The procedure leads to all kinds of relativistic and quantum‐electrodynamical effects, and can be shown for two‐particle systems to lead to the Bethe‐Salpeter equation. In the implementation an extension to the photonic Fock space is made, where the number of photons no longer is constant. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
How to diagnose hantavirus infections and detect them in rodents and insectivores
Authors: Vaheri Antti , Vapalahti Olli , Plyusnin Alexander 
Published: May 2008

AbstractHantaviruses are carried by rodents and insectivores in which they cause persistent and generally asymptomatic infections. Several hantaviruses can infect humans and many of them cause either haemorrhagic fever with renal syndrome (HFRS) in Eurasia or hantavirus cardiopulmonary syndrome (HCPS) in the Americas. In humans hantavirus infections are diagnosed using IgM‐capture tests but also by RT‐PCR detection of viral RNA. For detection of hantavirus infections in rodents and insectivores, serology followed by immunoblotting of, for example, lung tissue, and RT‐PCR detection of viral RNA may be used, and if of interest followed by sequencing and virus isolation. For sero/genotyping of hantavirus infections in humans and carrier animals neutralisation tests/RNA sequencing are required. Hantaviruses are prime examples of emerging and re‐emerging infections and it seems likely that many new hantaviruses will be detected in the near future. Copyright © 2008 John Wiley & Sons, Ltd.
Characterizing the capacity gain of stream control scheduling in MIMO wireless mesh networks
Authors: Wang Yue , Chiu Dah‐Ming , Lui John C. S. 
Published: May 2008

AbstractStream control (SC) has recently attracted attentions in the research of multiple input multiple output (MIMO) wireless networks as a potential way to improve network capacity. However, inappropriate use of SC may significantly degrade network capacity as well. In this paper, we provide the first formal study on SC scheduling in MIMO wireless mesh networks (WMNs). We derive the theoretical upper bound on network capacity gain of SC scheduling. We also provide an efficient scheduling algorithm and show that its achieved network capacity gain is close to its theoretical upper bound. Moreover, we point out the poor performance of a previous SC scheduling algorithm SCMA under the general settings of WMNs. This formal characterization provides a deeper understanding of steam control scheduling in MIMO WMNs. Copyright © 2008 John Wiley & Sons, Ltd.
Cell Culture Automation and Quality Engineering: A Necessary Partnership to Develop Optimized Manufacturing Processes for Cell-Based Therapies
Authors: Thomas R.J. , Chandra A. , Hourd P.C. , Williams D.J. 
Published: May 2008

The translation of experimental cell-based therapies to volume produced commercially successful clinical products that satisfy the regulator requires the development of automated manufacturing processes to achieve capable and scaleable processes that are both economic and able to meet the unpredictable demands of the market place. The Healthcare Engineering group at Loughborough has conducted novel demonstrators of the transfer of manual human cell culture processes to the CompacT SelecT (The Automation Partnership) automated cell culture platform, including an osteoblast cell line, embryonic carcinoma cell line, primary bone marrow-derived mesenchymal stem cells, primary umbilical cord-derived progenitor cells, and human embryonic stem cells. The work aims to develop and optimize automated cell culture processes for manufacturing cell-based therapies in a quality system and current good manufacturing practice (cGMP) compliant manner and is underpinned by the application of a six-sigma inspired quality engineering approach. In this technical brief, we outline the need for automated cell culture systems and automated process engineering for the manufacture of cell populations for therapeutic applications. We review the transfer of a manual cell culture process to an automated process and the subsequent methodology for process improvement using examples from our laboratory of the application of these principles to an important regenerative medicine cell type, the human mesenchymal stem cell. We believe that systematic process improvement methodologies combined with the process stability provided by automation are essential to engineer optimized cGMP compliant manufacturing processes that will be required to realize the promise of cell-based therapies.
Automated Application of a Novel High Yield, High Performance Tissue Culture Flask
Authors: Szymanski Stacey L. , Huff Kevin W. , Patel Amita D. , Murray Justin R. , Feasby James , Sharma Bethel V. , Young Denise K. , Strulovici Berta , Peltier Richard R. , Johnson Eric N. , Rush Alison 
Published: May 2008

As the drug discovery process evolves and demands more challenging and relevant assays, we have experienced a recent and significant escalation in the number of cell-based high-throughput assays for both small molecule and target identification screens. This has resulted in an increased need for the reproducible production of high quality cells in large quantities. Historically, manual cell culture was the only option available for providing cells in sufficient numbers for small molecule ultra-high-throughput screens (uHTSs), representing a technology gap in our automated cell culture process. Recently, we have applied an automated solution in the form of a novel 10-layer tissue culture flask, the HYPERFlask (Corning, Lowell, MA). This technology, when introduced as an upgrade to the SelecT (an automated cell culture system manufactured by The Automation Partnership, Ltd., Royston, England), provides a new approach to automating production of the high number of cells required for uHTS and consequently a highly desirable alternative to manual cell culture. The HYPERFlask has a surface area of 1720 cm2 and can yield up to 3 × 108 cells after 3 days in culture. This can be compared to a typical yield of 2 × 107 cells from a T175 flask (with a surface area of 175 cm2), the current standard flask type for automated cell culture on the SelecT. Cells grown in both flask types are of comparable quality, as demonstrated by equivalent cell viability, yield per cm2, functional response, and pharmacology.
Living with Irresolute Cell Lines in an Automated World
Authors: Hogan Christopher , Simons Sarah , Zhang Haiyan , Burdick Debra 
Published: May 2008

An automated cell-culture platform becomes the nucleus of an organization performing cell-based research. However, every cell-based project placed on the system brings unique challenges. With each cell line comes millions of years of evolutionary encumbrance and a genetic inclination driving unique phenotypic peculiarities. In vivo, diverse eukaryotic cells rely on their “mammalian host” for survival. An automated system must perform in vitro, the myriad actions needed to sustain multiple cell lines as well, hence becoming an “automated host.” Cells invariably, will endeavor to do as they please. Molding these cells into the operational bounds of a man-made system requires insight into the relationship between cell and machine. Citing our own experiences, we will describe herein the use of the SelecT automated cell-culture platform (The Automation Partnership, Hertfordshire, England) in our discovery and preclinical profiling programs at Novartis. Achieving the balance between cells and the automated environment, and accommodating variable cell dynamics are discussed.
A Bayesian method for jointly estimating allele age and selection intensity
Authors: SLATKIN MONTGOMERY 
Published: May 2008

SummaryThe problem of jointly estimating the intensity of past selection affecting an allele and the allele's age is formulated in a Bayesian framework. The prior distribution of allele age given its frequency is obtained from existing population genetics theory. The prior distribution of selection intensity is assumed to reflect the fact that positive selection on a new mutant is more likely to be weak than strong. The general approach is illustrated by the development of an importance sampling method applicable to low-frequency alleles. This method can be used either when the haplotypes of closely linked marker loci are known or when the lengths of linked ancestral chromosomal segments can be inferred. The method is illustrated with an application to the A− allele of G6PD in Africa. Because changes in allele frequency and recombination are both intrinsically stochastic, there are limits to the accuracy achievable with any method.
Asymmetrical mating patterns and the evolution of biased style-morph ratios in a tristylous daffodil
Authors: HODGINS KATHRYN A. , BARRETT SPENCER C. H. 
Published: May 2008

SummaryNon-random mating in plant populations can be influenced by numerous reproductive and demographic factors, including floral morphology and inter-plant distance. Here, we investigate patterns of outcrossed mating through male function inNarcissus triandrus, a tristylous, bee-pollinated wild daffodil from the Iberian Peninsula, to test pollen transfer models which predict that floral morphology promotes asymmetrical mating and biased morph ratios. Unlike other tristylous species,N. triandrushas an incompatibility system that permits intra-morph mating and long-level rather than mid-level stamens in the L-morph. Incomplete sex-organ reciprocity should result in significant intra-morph mating in the L-morph. We measured mating patterns in two L-biased populations – dimorphic (two style morphs) and trimorphic (three style morphs) – using multilocus genotyping and maximum-likelihood-based paternity analysis. We also examined the spatial distribution of style morphs and neutral markers to investigate the potential consequence of spatially restricted mating on morph ratios. As predicted, we detected significant amounts of intra-morph mating in the L-morph in both populations. Pollen transfer coefficients generally supported predictions based on the Darwinian hypothesis that anthers and stigmas of equivalent level promote pollinator-mediated cross-pollination in heterostylous populations. There was evidence of significant spatial aggregation of both style morphs and neutral markers in populations ofN. triandrus, probably as a result of restricted pollen and seed dispersal. Our results provide empirical support for theoretical models of pollen transfer, which indicate that the commonly observed L-biased morph ratios inNarcissusspecies result from significant intra-morph mating in the L-morph because of its atypical floral morphology.