bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development and characterization of organoclay‐filled polyoxymethylene nanocomposites for high performance applications
Authors: Jose Ajith James , Alagar M. 
Published: August 2011

AbstractThe present work focuses on the preparation and characterization of organo‐modified fluorohectorite (OFH) clay filled polyoxymethylene (POM) nanocomposites by melt mixing method. The dispersion of OFH clay in the polymer matrix was confirmed by X‐ray diffraction (XRD), atomic force microscopy (AFM), and transmission electron microscopy (TEM) analysis. The surface properties of the nanocomposites, assessed by contact angle measurements, showed increase in hydrophobicity relative to the neat polymer. From the measured contact angle values, various surface parameters such as total surface free energy, interfacial free energy, work of adhesion, spreading coefficient, and Girifalco‐Good's interaction parameter were calculated. The thermal, mechanical, and dielectric properties of the nanocomposites were found to be improved by the incorporation of OFH clay into the POM matrix. The aging studies of the nanocomposites carried out by immersing the samples in various solvents showed an increase in the retention of mechanical property by the addition of OFH clay into the POM matrix. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Synthesis and characterization of conducting gas barrier polyacrylonitrile/graphite nanocomposites
Authors: Prusty Gyanaranjan , Swain Sarat K 
Published: August 2011

AbstractGraphite platelets were expanded by functionalization with inorganic acids followed by strong thermal treatment. The expanded graphite (EG) was exfoliated on the polyacrylonitrile (PAN) matrix through in situ emulsion sonication technique with different proportions of EG. The Ultraviolet‐visible (UV) spectroscopy revealed the interaction between EG and PAN matrix. In Fourier Transform Infrared spectroscopy (FTIR), the chemical interaction between EG and the cyanide group of PAN was evidenced to the formation of PAN/EG composites. The X‐ray diffraction pattern of raw graphite (RG), expanded graphite (EG), polyacrylonitrile (PAN), and PAN/EG nanocomposites were evidenced the dispersion of EG with the PAN matrix. The morphology of EG, PAN, and PAN/EG composites were studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The tensile strength of PAN/EG nanocomposite was measured and found to be increased with increase in EG concentrations. The conductivity and impedance of composites were measured as function of EG concentration. It was found that, conductivity of composites gradually increased with the increase in EG loading. Oxygen permeability of PAN/EG was reduced substantially with rise of EG proportion. To investigate the flame retardancy behavior of PAN/EG nanocomposites, the limiting oxygen indexes were calculated. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers
Preparation of silk fibroin–poly(ethylene glycol) conjugate films through click chemistry
Authors: Sampaio Sandra , Miranda Teresa M. R. , Santos Jorge G. , Soares Graça M. B. 
Published: August 2011

AbstractAzide silk fibroin (azido SF) and alkyne terminal poly(ethylene glycol) (PEG) 2000 (acetylene‐terminal PEG 2000) were synthesized. Azido SF was reacted with acetylene‐terminal PEG 2000 to produce films via a copper‐mediated 1,3‐cycloaddition (‘click’ chemistry) generating a triazole linkage as the networking forming reaction. Through click chemistry, novel silk‐based films with various weight ratios were prepared and investigated. Fourier transform infrared, X‐ray diffraction and differential scanning calorimetry analyses showed that the ordered association of the PEG molecules is strongly constrained by the presence of the SF molecules and crosslinking and that the presence of acetylene‐terminal PEG 2000 in the films induced crystallization to a β‐sheet of SF chains. Water content and contact angle measurements indicated that the hydrophilicity of the films increased compared with SF. SF–PEG films exhibited smooth and rough structures, depending on degree of crosslinking and on the weight ratio of SF and PEG, as shown by scanning electron microscopy. Copyright © 2011 Society of Chemical Industry
Efficacy of intratracheal instillation of a meropenem/perfluorochemical suspension in acute lung injury
Authors: Jeng Mei‐Jy , Soong Wen‐Jue , Chiou Shr‐Yun , Wu Yu‐Tse , Tsai Tung‐Hu , Lin Chia‐Chun , Yang Chia‐Feng , Tsao Pei‐Chen , Lee Yu‐Sheng 
Published: August 2011

AbstractPerfluorochemical (PFC) is theoretically a good vehicle for delivering biological agents to the lungs. This study was designed to investigate the efficacy of intratracheal (IT) instillation of meropenem using PFC liquid as a vehicle in a piglet model of acute lung injury (ALI). Eighteen piglets were injured with lung lavages to induce ALI, and randomly assigned to intravenous (IV) infusion or IT instillation groups, the latter using either PFC or normal saline (NS) as a delivery vehicle for meropenem. Blood samples were obtained at 0, 15, 30, and 60 min, and then hourly for 6 hr. Sera and extracts of lung tissues were assayed for meropenem content using high‐performance liquid chromatography. We found that the IV group had significantly higher serum concentrations of meropenem during the first hour after dosing (P < 0.05). There was no significant difference between IT‐PFC and IT‐NS groups regarding changes in serum meropenem concentrations during the experimental period. Meropenem content in lung tissue was highest in the IT‐PFC group, lower in the IT‐NS group, and undetectable in the IV group (P < 0.05). The IT‐NS group had the highest peak inspiratory pressure (P < 0.05), but there were no significant differences in other cardiopulmonary parameters among the three groups studied. In conclusion, meropenem can be safely administered to injured lungs by IT instillation in a meropenem/PFC suspension. Using PFC liquid as an IT vehicle to carry meropenem provides better pulmonary drug depositions than IV injection or IT instillation with NS in ALI. Pediatr Pulmonol. 2012; 47:189–198. © 2011 Wiley Periodicals, Inc.
The differing effects of agent and founder CEOs on the firm's market expansion
Authors: Souder David , Simsek Zeki , Johnson Scott G. 
Published: August 2011

AbstractThis paper builds and tests the thesis that CEO influence evolves differently for founders and agents. We theorize that at the beginning of their tenures, founder CEOs can pursue market expansion more aggressively than agent CEOs, because they take office with the combination of motivation, power, and requisite knowledge that agent CEOs build over time. Subsequently, however, founder CEOs have less access to the administrative infrastructure necessary to sustain a growing firm, making them less able than agent CEOs to continue market expansion mid‐tenure and more severely constrained by market complexity. A longitudinal study of cable television operators confirms that the firm's market expansion follows an inverted U‐shape for agents and a downward slope for founders, while market complexity reduces market expansion, especially for founders. Copyright © 2011 John Wiley & Sons, Ltd.
Exposure, infection, systemic cytokine levels and antibody responses in young children concurrently exposed to schistosomiasis and malaria
Authors: IMAI NATSUKO , RUJENI NADINE , NAUSCH NORMAN , BOURKE CLAIRE D. , APPLEBY LAURA J. , COWAN GRAEME , GWISAI REGGIS , MIDZI NICHOLAS , CAVANAGH DAVID , MDULUZA TAKAFIRA , TAYLOR DAVID , MUTAPI FRANCISCA 
Published: August 2011

SUMMARYDespite the overlapping distribution ofSchistosoma haematobiumandPlasmodium falciparuminfections, few studies have investigated early immune responses to both parasites in young children resident in areas co-endemic for the parasites. This study measures infection levels of both parasites and relates them to exposure and immune responses in young children. Levels of IgM, IgE, IgG4 directed against schistosome cercariae, egg and adult worm and IgM, IgG directed againstP. falciparumschizonts and the merozoite surface proteins 1 and 2 together with the cytokines IFN-γ, IL-4, IL-5, IL-10 and TNF-αwere measured by ELISA in 95 Zimbabwean children aged 1–5 years. Schistosome infection prevalence was 14·7% and that ofPlasmodiuminfection was 0% in the children. 43. 4% of the children showed immunological evidence of exposure to schistosome parasites and 13% showed immunological evidence of exposure toPlasmodiumparasites. Schistosome–specific responses, indicative of exposure to parasite antigens, were positively associated with cercariae-specific IgE responses, whilePlasmodium-specific responses, indicative of exposure to parasite antigens, were negatively associated with responses associated with protective immunity againstPlasmodium. There was no significant association between schistosome-specific andPlasmodium-specific responses. Systemic cytokine levels rose with age as well as with schistosome infection and exposure. Overall the results show that (1) significantly more children are exposed to schistosome andPlasmodiuminfection than those currently infected and; (2) the development of protective acquired immunity commences in early childhood, although its effects on infection levels and pathology may take many years to become apparent.
Association of MMP-2 and MMP-9 with clinical outcome of neurocysticercosis
Authors: VERMA AVANTIKA , PRASAD KASHI N. , NYATI KISHAN K. , SINGH SATYENDRA K. , SINGH ALOUKICK K. , PALIWAL VIMAL K. , GUPTA RAKESH K. 
Published: August 2011

SUMMARYMatrix metalloproteinases (MMPs) are the major endopeptidases involved in proteolysis of blood brain barrier (BBB) during central nervous system (CNS) infections. The present study detected serum levels and activities of MMP-2 and MMP-9 in patients with neurocysticercosis (NCC) and their association with symptomatic disease. In total, 68 individuals with NCC (36 symptomatic patients with active seizures and 32 asymptomatic individuals) and 37 healthy controls were enrolled for the study. Serum MMP-2 and MMP-9 levels and their activities were measured by ELISA and gel zymography respectively. Mean serum MMP-2 levels (ng/ml) were higher both in asymptomatic and symptomatic NCC cases compared to healthy controls. However, significantly higher levels of serum MMP-9 (ng/ml) were detected only in symptomatic NCC patients compared to asymptomatic NCC cases and healthy controls. Levels of both MMPs positively correlated with symptomatic NCC. Serum MMP-2 activities were significantly higher in symptomatic and asymptomatic NCC compared to healthy controls whereas serum MMP-9 activity was significantly associated with symptomatic NCC compared to healthy controls and asymptomatic NCC. In conclusion, the elevated level of MMP-9 in serum appears to play an important role in the development of symptoms i.e. active seizures in patients with NCC. However, further studies are needed to elucidate its precise role in disease pathogenesis.
Hierarchical structure and dynamics of an ionic liquid 1-octyl-3-methylimidazolium chloride
Authors: Yamamuro Osamu , Yamada Takeshi , Kofu Maiko , Nakakoshi Masamichi , Nagao Michihiro 
Published: August 2011

We have performed the heat capacity, neutron diffraction, and neutron quasielastic scattering measurements of an ionic liquid 1-octyl-3-methylimidazolium chloride (C8mimCl). The heat capacity data revealed that C8mimCl exhibits a glass transition with a large heat capacity jump at Tg = 214 K, which is lower than Tg of C4mimCl with a shorter alkyl-chain. In the neutron diffraction measurement for a deuterated analogue, d-C8mimCl, the peaks associated with the inter-domain, inter-ionic, and inter-alkyl-chain correlations appeared at (3, 11, and 14) nm−1, respectively. The temperature dependence of these peaks indicates that the packing of the alkyl-chains becomes more compact and the domains become more vivid and larger as decreasing temperature. The quasielastic neutron scattering measurements using neutron spin echo and time-of-flight type instruments demonstrated that C8mimCl has faster relaxations probably owing to the alkyl-group and a slower relaxation owing to the ions. The latter relaxation, which is related to the glass transition, is of non-exponential as in the α relaxation of glass-forming molecular liquids. The relaxation of domains could not be observed in the present experiment but should have relaxation times longer than 100 ns. This is the first report to clarify temperature dependence of the hierarchical structure and relaxations simultaneously for a typical ionic liquid.
Human peripheral blood CD4 T cell-engrafted non-obese diabetic-scid IL2rγnull H2-Ab1 tm1GruTg (human leucocyte antigen D-related 4) mice: a mouse model of human allogeneic graft-versus-host disease
Authors: Covassin L , Laning J , Abdi R , Langevin D L , Phillips N E , Shultz L D , Brehm M A 
Published: August 2011

SummaryGraft-versus-host disease (GVHD) is a life-threatening complication of human allogeneic haematopoietic stem cell transplantation. Non-obese diabetic (NOD)-scid IL2rγnull (NSG) mice injected with human peripheral blood mononuclear cells (PBMC) engraft at high levels and develop a robust xenogeneic (xeno)-GVHD, which reproduces many aspects of the clinical disease. Here we show that enriched and purified human CD4 T cells engraft readily in NSG mice and mediate xeno-GVHD, although with slower kinetics compared to injection of whole PBMC. Moreover, purified human CD4 T cells engraft but do not induce a GVHD in NSG mice that lack murine MHC class II (NSG-H2-Ab1 tm1Gru, NSG-Ab°), demonstrating the importance of murine major histocompatibility complex (MHC) class II in the CD4-mediated xeno-response. Injection of purified human CD4 T cells from a DR4-negative donor into a newly developed NSG mouse strain that expresses human leucocyte antigen D-related 4 (HLA-DR4) but not murine class II (NSG-Ab° DR4) induces an allogeneic GVHD characterized by weight loss, fur loss, infiltration of human cells in skin, lung and liver and a high level of mortality. The ability of human CD4 T cells to mediate an allo-GVHD in NSG-Ab° DR4 mice suggests that this model will be useful to investigate acute allo-GVHD pathogenesis and to evaluate human specific therapies.
Chronic lymphocytic leukaemia cells drive the global CD4+ T cell repertoire towards a regulatory phenotype and leads to the accumulation of CD4+ forkhead box P3+ T cells
Authors: Piper K P , Karanth M , McLarnon A , Kalk E , Khan N , Murray J , Pratt G , Moss P A H 
Published: August 2011

SummaryAdvanced chronic lymphocytic leukaemia (CLL) is associated with profound immunodeficiency, including changes in T regulatory cells (Tregs). We determined the pattern of expression of forkhead box P3 (FoxP3), CD25, CD27 and CD127 and showed that the frequency of CD4+FoxP3+ T cells was increased in CLL patients (12% versus 8% in controls). This increase was seen only in advanced disease, with selective expansion of FoxP3-expressing cells in the CD4+CD25low population, whereas the number of CD4+CD25highFoxP3+ cells was unchanged. CD4+CD25low cells showed reduced expression of CD127 and increased CD27, and this regulatory phenotype was also seen on all CD4 T cells subsets in CLL patients, irrespective of CD25 or FoxP3 expression. Incubation of CD4+ T cells with primary CLL tumours led to a sixfold increase in the expression of FoxP3 in CD4+CD25- T cells. Patients undergoing treatment with fludarabine demonstrated a transient increase in the percentage of CD4+FoxP3+ T cells, but this reduced to normal levels post-treatment. This work demonstrates that patients with CLL exhibit a systemic T cell dysregulation leading to the accumulation of CD4+FoxP3+ T cells. This appears to be driven by interaction with malignant cells, and increased understanding of the mechanisms that are involved could provide novel avenues for treatment.
The rate of permafrost carbon release under aerobic and anaerobic conditions and its potential effects on climate
Authors: Lee Hanna , Schuur Edward A. G. , Inglett Kanika S. , Lavoie Martin , Chanton Jeffrey P. 
Published: August 2011

AbstractRecent observations suggest that permafrost thaw may create two completely different soil environments: aerobic in relatively well‐drained uplands and anaerobic in poorly drained wetlands. The soil oxygen availability will dictate the rate of permafrost carbon release as carbon dioxide (CO2) and as methane (CH4), and the overall effects of these emitted greenhouse gases on climate. The objective of this study was to quantify CO2 and CH4 release over a 500‐day period from permafrost soil under aerobic and anaerobic conditions in the laboratory and to compare the potential effects of these emissions on future climate by estimating their relative climate forcing. We used permafrost soils collected from Alaska and Siberia with varying organic matter characteristics and simultaneously incubated them under aerobic and anaerobic conditions to determine rates of CO2 and CH4 production. Over 500 days of soil incubation at 15 °C, we observed that carbon released under aerobic conditions was 3.9–10.0 times greater than anaerobic conditions. When scaled by greenhouse warming potential to account for differences between CO2 and CH4, relative climate forcing ranged between 1.5 and 7.1. Carbon release in organic soils was nearly 20 times greater than mineral soils on a per gram soil basis, but when compared on a per gram carbon basis, deep permafrost mineral soils showed carbon release rates similar to organic soils for some soil types. This suggests that permafrost carbon may be very labile, but that there are significant differences across soil types depending on the processes that controlled initial permafrost carbon accumulation within a particular landscape. Overall, our study showed that, independent of soil type, permafrost carbon in a relatively aerobic upland ecosystems may have a greater effect on climate when compared with a similar amount of permafrost carbon thawing in an anaerobic environment, despite the release of CH4 that occurs in anaerobic conditions.
The role of cyanobacteria in Southern California salt marsh food webs
Authors: Currin Carolyn A. , Levin Lisa A. , Talley Theresa S. , Michener Robert , Talley Drew 
Published: August 2011

AbstractUnderstanding wetland food webs is critical for effective habitat management, restoration and conservation. Microalgae are recognized as key food sources for marsh invertebrates but the importance of different groups under various conditions is rarely examined. We tested the hypothesis that faunal utilization of microalgae, and cyanobacteria in particular, is significant in Southern California created and natural salt marshes but varies with habitat type (creek bank versus marsh interior) and season (spring versus autumn). We used stable isotope analysis and mixing models (IsoSource) to compare food webs in adjacent young (created) and mature (natural) salt marshes. Isotopic values of some primary producers, macrofauna, epifauna, and fish demonstrated significant differences between the adjacent salt marshes. δ13C and δ34S values of the benthic microalgal community varied with taxonomic composition (diatoms versus cyanobacteria) and to a lesser extent with season. Depleted δ15N values of benthic diatoms and macroalgae indicated that N2 fixed within algal mats was recycled within the benthic algal community. Marsh fauna, including most major macrofauna taxal, Cerithidea, and Fundulus, also exhibited seasonal differences in isotopic composition, and Cerithidea and selected macrofauna (oligochaetes, polychaetes) from the marsh interior were more enriched in 13C and depleted in 15N than those from the creek bank. In the young marsh, the cyanobacteria contributed a minimum of 17–100% of the primary production in food webs supporting macrofauna, and cyanobacteria contributed at least 40% of the primary production included in Cerithidea and Fundulus food webs. A wider range of primary producers contributed to food webs in the mature marsh. Cyanobacteria were a greater source of trophic support for macrofauna from the marsh interior than the creek bank, whereas Spartina was a more important food source for creek bank macrofauna in both marshes. Insect larvae largely consumed cyanobacteria, whereas polychaetes exhibited greater utilization of Spartina. Phytoplankton was the primary food resource for mussels in both marshes. Although the spatial and temporal complexity of food webs has traditionally been collapsed into the study of relatively simplified food webs, isotope signatures reveal fine‐scale patterns in food web structure that may be used to make more accurate assessments of ecosystem state. Accurate interpretation of marsh trophic structure using natural abundance stable isotopes requires fine‐scale resolution in space and time, a large number of samples, and a high level of taxonomic resolution.
Functional webs for freeform architecture
Authors: Deng B. , Pottmann H. , Wallner J. 
Published: August 2011

AbstractRationalization and construction‐aware design dominate the issue of realizability of freeform architecture. The former means the decomposition of an intended shape into parts which are sufficiently simple and efficient to manufacture; the latter refers to a design procedure which already incorporates rationalization. Recent contributions to this topic have been concerned mostly with small‐scale parts, for instance with planar faces of meshes. The present paper deals with another important aspect, namely long‐range parts and supporting structures. It turns out that from the pure geometry viewpoint this means studying families of curves which cover surfaces in certain well‐defined ways. Depending on the application one has in mind, different combinatorial arrangements of curves are required. We here restrict ourselves to so‐called hexagonal webs which correspond to a triangular or tri‐hex decomposition of a surface. The individual curve may have certain special properties, like being planar, being a geodesic, or being part of a circle. Each of these properties is motivated by manufacturability considerations and imposes constraints on the shape of the surface. We investigate the available degrees of freedom, show numerical methods of optimization, and demonstrate the effectivity of our approach and the variability of construction solutions derived from webs by means of actual architectural designs.?
Surface Patches from Unorganized Space Curves
Authors: Abbasinejad Fatemeh , Joshi Pushkar , Amenta Nina 
Published: August 2011

AbstractRecent 3D sketch tools produce networks of three‐space curves that suggest the contours of shapes. The shapes may be non‐manifold, closed three‐dimensional, open two‐dimensional, or mixed. We describe a system that automatically generates intuitively appealing piecewise‐smooth surfaces from such a curve network, and an intelligent user interface for modifying the automatically chosen surface patches. Both the automatic and the semi‐automatic parts of the system use a linear algebra representation of the set of surface patches to track the topology. On complicated inputs from ILoveSketch [BBS08], our system allows the user to build the desired surface with just a few mouse‐clicks.
An Optimal Transport Approach to Robust Reconstruction and Simplification of 2D Shapes
Authors: de Goes Fernando , Cohen‐Steiner David , Alliez Pierre , Desbrun Mathieu 
Published: August 2011

AbstractWe propose a robust 2D shape reconstruction and simplification algorithm which takes as input a defect‐laden point set with noise and outliers. We introduce an optimal‐transport driven approach where the input point set, considered as a sum of Dirac measures, is approximated by a simplicial complex considered as a sum of uniform measures on 0‐ and 1‐simplices. A fine‐to‐coarse scheme is devised to construct the resulting simplicial complex through greedy decimation of a Delaunay triangulation of the input point set. Our method performs well on a variety of examples ranging from line drawings to grayscale images, with or without noise, features, and boundaries.