bluuebunny/crossref_metadata_2025_split huggingface dataset:
High‐frequency precipitation changes in southeastern Africa due to anthropogenic forcing
Authors: Rocha Alfredo , Melo‐Gonçalves Paulo , Marques Carlos , Ferreira Juan , Castanheira José M. 
Published: September 2007

AbstractThis study evaluates differences in the precipitation regime over southeastern Africa simulated by two global climate models under present (1961–1990) and future (2071–2100) conditions as a result of greenhouse gases anthropogenic forcing. In particular, the characteristics of precipitation episodes with duration of some days are compared in both simulations. Precipitation in the models is previously compared to precipitation data obtained from the ERA‐40 reanalyses and the Climate Prediction Centre (CPC), Climate Prediction Merged Analysis of Precipitation (CMAP). A precipitation episode is defined here as a period with a minimum number of consecutive days with daily precipitation above a threshold amount.We consider a great range of episodes according to the preset threshold number of days (1–15 days) and daily precipitation amount (1–15 mm/day). For both climates, the number of episodes, their average duration and intensity are compared. The analysis is performed for both models. The results clearly show a tendency for a decrease in the number of episodes, in most of the region and for most episode categories, due to anthropogenic climate change. The duration of the episodes is reduced in the future climate for weak episode categories. For mild to intense episodes their duration is expected to increase over a small part of the region. The intensity of all episode categories is increased practically over the whole region. The spatial structure of these changes and its distribution according to the episode category are documented in this study. Copyright © 2007 Royal Meteorological Society
Characterization of the Inhibition of Enveloped Virus Infectivity by the Cationic Acrylate Polymer Eudragit E100
Authors: Alasino Roxana V. , Bianco Ismael D. , Vitali María S. , Zarzur Jorge A. , Beltramo Dante M. 
Published: September 2007

AbstractThe antiviral effects of the cationic acrylate polymer E100 on a panel of lipid‐enveloped viruses and the interactions involved are studied. The treatment of several common viruses with E100 induced a dose‐dependent inhibition of the infectivity of viruses below the detection limit of the assays employed. Similarly, the treatment of human sera infected with HIV or HCV reduced virus RNA plasma levels to undetectable values. This implies that Eudragit E100 can interact with enveloped viruses, even in the presence of proteins, through a mechanism that is not reversed by titration of the positively charged groups of the polymer, opening the possibility to remove viral particles with the polymer as it is eliminated.magnified image
Design and Synthesis of Cellulose Derivatives with Antioxidant Activity
Authors: Trombino Sonia , Cassano Roberta , Bloise Ermelinda , Muzzalupo Rita , Leta Sonia , Puoci Francesco , Picci Nevio 
Published: September 2007

AbstractIn this study we report the synthesis and characterisation of cellulose ferulate, lipoate and α‐tocopherulate, and their ability to inhibit lipid peroxidation in rat‐liver microsomal membranes, induced in vitro by two different sources of free radicals: tert‐butyl hydroperoxide and 2,2′‐azobis‐(2‐amidinopropane). We also compared the antioxidant efficiency of the ferulate derivatives obtained through two different synthetic runs, and of a tocopherulate derivative prepared from 6‐carboxycellulose. This study showed that the designed systems, preserving the antioxidant activity of the free substrates, are more effective in protecting from tert‐butyl hydroperoxide than from 2,2′‐azobis‐(2‐amidinopropane). Moreover, the cellulose ferulate with the higher degree of substitution acted as the best antioxidant.magnified image
New Polyester‐Based Terpyridine Macroligands and their Blue Iron(II) Complexes
Authors: Winter Andreas , Schubert Ulrich S. 
Published: September 2007

AbstractA library of hydroxy‐ and amino‐functionalized Kröhnke‐type terpyridines have been used to synthesize new terpyridine end‐functionalized poly(ε‐caprolactone)s and poly(L‐lactide)s, via Sn(II)‐catalyzed ring‐opening polymerization. It has also been possible to prepare a set of metallo‐supramolecular AA homopolymers by complexation with Fe(II) metal ions. All of these complexes have been fully characterized. Stable metallo‐polymers with an intense blue color have been obtained from the quaternized macroligands. This color property might be of great interest for the design of functional supramolecular materials, with respect to color tuning and optical applications.magnified image
RAFT Synthesis and Solution Properties of pH‐Responsive Styrenic‐Based AB Diblock Copolymers of 4‐Vinylbenzyltrimethylphosphonium Chloride with N,N‐Dimethylbenzylvinylamine
Authors: Lowe Andrew B. , Wang Ran , Tiriveedhi Venkataswarup , Butko Peter , McCormick Charles L. 
Published: September 2007

AbstractThe RAFT synthesis and solution properties of AB block copolymers of 4‐vinylbenzyltrimethylphosphonium chloride (TMP) and N,N‐dimethylbenzylvinylamine (DMBVA) is described. The pH‐dependent self‐assembly properties of the AB diblock copolymers were examined using of 1H NMR, DLS, and fluorescence spectroscopy. The size of the polymeric aggregates depends on the block copolymer composition/molecular mass. The self assembly is completely reversible, as predicted from the tunable hydrophilicity/hydrophobicity of the DMBVA residues. The AB diblock copolymers can be effectively locked in the self‐assembled state using a straightforward core crosslinking reaction between the tertiary amine residues of DMBVA and difunctional 1,4‐bis(bromomethyl)benzene.magnified image
(Photo)crosslinkable Smectic LC Main‐Chain Polymers
Authors: Beyer Patrick , Braun Lydia , Zentel Rudolf 
Published: September 2007

AbstractThis paper presents the synthetic route to SmA LC main‐chain polymers, that can be (photo)crosslinked without solvent in the bulk phase. They are based on soluble polymalonates, in which higher ordered phases can be suppressed by copolymerization with a laterally brominated biphenyl. Two routes were developed to incorporate the crosslinkable groups into the polyester backbone. The first consists in the incorporation of phenols into the polyester. These phenols are not reactive enough to participate in the transesterification reaction used to build up the polymer, but they can be esterified afterwards with acrylates. Thermally or photochemically created radicals then start the crosslinking. The second route is based on the incorporation of benzophenone as side group. It allows a photochemical crosslinking. Crosslinked fibers (monodomains) show the potential of the smectic LC main‐chain elastomers as actuators.magnified image
Robust Organic/Inorganic Hybrid Porous Thin Films via Breath‐Figure Method and Gelation Process
Authors: Zhang Ke , Zhang Liwei , Chen Yongming 
Published: September 2007

AbstractA novel organic/inorganic hybrid honeycomb patterned porous thin film was prepared using the breath‐figure method combined with a sol‐gel process. An in situ formed gelable block copolymer, formed by mixing poly(styrene‐alt‐maleic anhydride)‐block‐polystyrene (P(St‐a‐MAn)‐b‐PS) and 3‐aminopropyltrimethoxysilane (APS), was used as the structure directing agent. The porous film produced was dipped into an acid aqueous solution to induce a sol‐gel process in the wall of film. As a result of gelation, the structure of this film transformed into a crosslinked silica oxide hybridized with PS, and this film resisted those organic solvents which were once good solvents for the copolymer precursor.magnified image
A Hermite reproducing kernel approximation for thin‐plate analysis with sub‐domain stabilized conforming integration
Authors: Wang Dongdong , Chen Jiun‐Shyan 
Published: September 2007

AbstractA Hermite reproducing kernel (RK) approximation and a sub‐domain stabilized conforming integration (SSCI) are proposed for solving thin‐plate problems in which second‐order differentiation is involved in the weak form. Although the standard RK approximation can be constructed with an arbitrary order of continuity, the proposed approximation based on both deflection and rotation variables is shown to be more effective in solving plate problems. By imposing the Kirchhoff mode reproducing conditions on deflectional and rotational degrees of freedom simultaneously, it is demonstrated that the minimum normalized support size (coverage) of kernel functions can be significantly reduced. With this proposed approximation, the Galerkin meshfree framework for thin plates is then formulated and the integration constraint for bending exactness is also derived. Subsequently, an SSCI method is developed to achieve the exact pure bending solution as well as to maintain spatial stability. Numerical examples demonstrate that the proposed formulation offers superior convergence rates, accuracy and efficiency, compared with those based on higher‐order Gauss quadrature rule. Copyright © 2007 John Wiley & Sons, Ltd.
Prenatally diagnosed fetal lung lesions with associated conotruncal heart defects: Is there a genetic association?
Authors: Hüsler Margaret R. , Wilson R. Douglas , Rychik Jack , Bebbington Michael W. , Johnson Mark P. , Mann Stephanie E. , Hedrick Holly L. , Adzick Scott 
Published: September 2007

AbstractCongenital lung malformation can easily be diagnosed by prenatal ultrasound. Associated extrapulmonary malformations such as heart defects and chromosomal aberrations are rare.ObjectiveThe objective of this study was to describe the natural history, outcome and other associated malformations in fetuses with lung lesions and an associated heart defect.MethodsRetrospective analysis of 4 cases of prenatally diagnosed fetal CCAMs and hybrid lesions with an associated heart defect and review of 8 cases in the literature.ResultsAt a single referral center 1.9% of the fetuses with Congenital cystic adenomatoid malformation (CCAM) were diagnosed with an associated heart defect. Seven of the total 12 cases (58%) reviewed had a conotruncal heart abnormality. Chromosomal abnormalities were found in 5 (42%) of the cases.ConclusionThis retrospective review shows that karyotyping in fetal lung lesions with an associated heart defect or isolated large lung lesions is indicated. It also suggests that there is a subpopulation of fetuses with CCAMs who have conotruncal heart defects. This finding may suggest a common genetic background. Copyright © 2007 John Wiley & Sons, Ltd.
Comparison of potential solar electricity output from fixed‐inclined and two‐axis tracking photovoltaic modules in Europe
Authors: Huld Thomas , Šúri Marcel , Dunlop Ewan D. 
Published: September 2007

AbstractWe present an approach to determine the potential energy gains of flat plate non‐concentrating photovoltaic systems for the case of two‐axis tracking and two inclination angles with fixed orientation (assuming biannual adjustment) compared to the configuration of single fixed optimum angle. The calculation is based on the Photovoltaic Geographic Information System (PVGIS), which integrates modelling tools with the pan‐European solar radiation database. The results indicate that in the case of a PV system with two seasonal inclination angles, the maximum yearly gains, compared to the single fixed optimum angle, do not exceed 60–70 kWh per kWp in the Mediterranean region, while in the Baltic and North Sea regions this configuration gives less than 20 kWh extra. For the case of two‐axis tracking, the relative energy gain compared to single fixed optimum angle is highest in the Northern latitudes but the absolute gain is much higher in the South. Typical yearly gains in Portugal and the Mediterranean region are in the range of 400–600 kWh per kWp. The smallest absolute increase is found in the Northwest and Central Europe including the British Isles, where it is lower than 250 kWh per kWp. For crystalline silicon we also investigate the effects of temperature and shallow‐angle reflectivity on the comparison between fixed and tracking systems. While both effects reduce the overall energy output, the temperature degradation is stronger for tracking systems while the reflectivity reduces output more for fixed systems. The combined effect is almost equal for fixed and two‐axis tracking systems. Copyright © 2007 John Wiley & Sons, Ltd.
Silicon nitride coating and crucible—effects of using upgraded materials in the casting of multicrystalline silicon ingots
Authors: Olsen E. , Øvrelid E. J. 
Published: September 2007

AbstractA method for removal of metallic contaminants from commercial Si3N4‐powders has been developed. The method is based on acid leaching and shows promising results. Analyses show that the content of both intermetallic compunds as Fe, Ti and Al as well as O are significantly reduced. Clean, synthetic fused silica crucibles have been used along with normal sintered ones based on natural quartz. The crucibles were coated with normal, commercial silicon nitride powder and with purified Si3N4in a cleanest possible environment. The crucibles were then used as vessels for directional solidification of multicrystalline silicon in a pilot scale furnace. The average lifetime of minority charge carriers in the cast silicon was determined by quasi steady state photoconductance (QSSPC) from the bottom to the top of the ingots. These varied in a systematic way, so that the materials cast in the pure environment had significantly higher values than the materials cast with conventional coating‐ and crucible materials. The maximum values for the lifetimes in the individual ingots varied from 7 to 135 µs. Copyright © 2007 John Wiley & Sons, Ltd.
Analyses of intricate kinetics of the serum proteome during and after colon surgery by protein expression time series
Authors: Roelofsen Han , Alvarez‐Llamas Gloria , Dijkstra Martijn , Breitling Rainer , Havenga Klaas , Bijzet Johan , Zandbergen Wouter , de Vries Marcel P. , Ploeg Rutger J. , Vonk Roel J. 
Published: September 2007

AbstractMonitoring changes in serum protein expression in response to acute events such as trauma, infection or drug intervention may reveal key proteins of great value in predicting recovery or treatment response. Concerted actions of many proteins are expected. Proteins sharing similar expression changes may function in the same physiological process. As a model we analyzed expression changes in serum of colon cancer patients, before, during, and after laparoscopic colon resection. Eight samples were taken from each of four patients before, during, and up to 5 days after surgery. Total serum and a low molecular weight fraction were analyzed by SELDI‐TOF‐MS. In total 146 masses were detected. A principal components analysis (PCA) illustrates the temporal variation in the postsurgery proteome. Time series for each mass could be clustered into four distinct groups based on similarity in expression pattern. Two masses of 11.4 and 11.6 kDa, part of a slow response cluster, were identified as forms of the acute phase protein serum amyloid A (SAA). Fourteen more proteins belong to this cluster and may also function in acute phase response. We present an approach to analyze temporal variation in the proteome. This approach may be useful to evaluate surgical, nutritional, and pharmacological interventions.
Global proteomic profiling of native outer membrane vesicles derived from Escherichia coli
Authors: Lee Eun‐Young , Bang Joo Young , Park Gun Wook , Choi Dong‐Sic , Kang Ji Seoun , Kim Hyun‐Jung , Park Kyong‐Su , Lee Jeong‐Ok , Kim Yoon‐Keun , Kwon Kyung‐Hoon , Kim Kwang‐Pyo , Gho Yong Song 
Published: September 2007

AbstractGram‐negative bacteria constitutively secrete native outer membrane vesicles (OMVs) into the extracellular milieu. Although recent progress in this area has revealed that OMVs are essential for bacterial survival and pathogenesis, the mechanism of vesicle formation and the biological roles of OMVs have not been clearly defined. Using a proteomics approach, we identified 141 protein components of Escherichia coli‐derived native OMVs with high confidence; two separate analyses yielded identifications of 104 and 117 proteins, respectively, with 80 proteins overlapping between the two trials. In the group of identified proteins, the outer membrane proteins were highly enriched, whereas inner membrane proteins were lacking, suggesting that a specific sorting mechanism for vesicular proteins exists. We also identified proteins involved in vesicle formation, the removal of toxic compounds and attacking phage, and the elimination of competing organisms, as well as those involved in facilitating the transfer of genetic material and protein to other bacteria, targeting host cells, and modulating host immune responses. This study provides a global view of native bacterial OMVs. This information will help us not only to elucidate the biogenesis and functions of OMV from nonpathogenic and pathogenic bacteria but also to develop vaccines and antibiotics effective against pathogenic strains.
Effect of pendent oxyethylene moieties on the properties of aromatic polyisophthalamides
Authors: Ferreiro Juan J. , de la Campa José G. , Lozano Angel E. , de Abajo Javier , Preston Jack 
Published: September 2007

AbstractTwelve novel polyisophthalamides containing short sequences of oxyethylene as pendent substituents were synthesized by the reaction of three aromatic diamine monomers and four novel diacid monomers containing pendent oxyethylene units. Two of the diacid monomers were derived from 5‐hydroxyisophthalic acid and the other two diacid monomers were derived from 5‐aminoisophthalic acid. The polymers were prepared in high yield and high molecular weight by the phosphorylation method of polycondensation. All of the polymers were soluble in organic aprotic solvents at room temperature and gave creasable films by casting from solution. The mechanical properties of the films were reasonably good, with tensile strengths in the range of 70–100 MPa and moduli around 2.5 GPa. However, the presence of the oxyethylene side sequences greatly diminished the thermal resistance and the glass transition temperatures of the present polymers compared with wholly aromatic polyisophthalamides. A study was also made on the effect of the chemical composition on water uptake. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45:4671–4683, 2007
Lattice simulations of cotranslational folding of single domain proteins
Authors: Wang Peiyu , Klimov Dmitri K. 
Published: September 2007

AbstractWe use lattice protein models and Monte Carlo simulations to study cotranslational folding of small single domain proteins. We show that the assembly of native structure begins during late extrusion stages, but final formation of native state occurs during de novo folding, when all residues are extruded. There are three main results in our study. First, for the sequences displaying two‐state refolding mechanism de novo cotranslational folding pathway differs from that sampled in in vitro refolding. The change in folding pathways is due to partial assembly of native interactions during extrusion that results in different starting conditions for in vitro refolding and for de novo cotranslational folding. For small single domain proteins cotranslational folding is slower than in vitro refolding, but is generally fast enough to be completed before the release from a ribosome. Second, we found that until final stages of biosynthesis cotranslational folding is essentially equilibrium. This observation is explained by low stability of structured states for partially extruded chains. Finally, our data suggest that the proteins, which refold in vitro slowly via intermediates, complete their de novo folding after the release from a ribosome. Comparison of our lattice cotranslational simulations with recent experimental and computational studies is discussed. Proteins 2008. © 2007 Wiley‐Liss, Inc.
New insight into long‐range nonadditivity within protein double‐mutant cycles
Authors: Istomin Andrei Y. , Gromiha M. Michael , Vorov Oleg K. , Jacobs Donald J. , Livesay Dennis R. 
Published: September 2007

AbstractAdditivity principles in chemistry, biochemistry, and biophysics have been used extensively for decades. Nevertheless, it is well known that additivity frequently breaks down in complex biomacromolecules. Nonadditivity within protein double mutant free energy cycles of spatially close residue pairs is a generally well‐understood phenomenon, whereas a robust description of nonadditivity extending over large distances remains to be developed. Here, we test the hypothesis that the mutational effects tend to be nonadditive if two structurally well‐separated mutated residues belong to the same rigid cluster within the wild type protein, and additive if they are located within different clusters. We find the hypothesis to be statistically significant with P‐values that range from 10−5 to 10−6. To the best of our knowledge, this result represents the first demonstration of a statistically significant preponderance for nonadditivity over long distances. These findings provide new insight into the origins of long‐range nonadditivity in double mutant cycles, which complements the conventional wisdom that nonadditivity arises in double mutations involving contacting residues. Consequently, these results should have far‐reaching implications for a proper understanding of protein stability, structure/function analyses, and protein design. Proteins 2008. © 2007 Wiley‐Liss, Inc.
Docking of protein molecular surfaces with evolutionary trace analysis
Authors: Kanamori Eiji , Murakami Yoichi , Tsuchiya Yuko , Standley Daron M. , Nakamura Haruki , Kinoshita Kengo 
Published: September 2007

AbstractWe have developed a new method to predict protein– protein complexes based on the shape complementarity of the molecular surfaces, along with sequence conservation obtained by evolutionary trace (ET) analysis. The docking is achieved by optimization of an object function that evaluates the degree of shape complementarity weighted by the conservation of the interacting residues. The optimization is carried out using a genetic algorithm in combination with Monte Carlo sampling. We applied this method to CAPRI targets and evaluated the performance systematically. Consequently, our method could achieve native‐like predictions in several cases. In addition, we have analyzed the feasibility of the ET method for docking simulations, and found that the conservation information was useful only in a limited category of proteins (signal related proteins and enzymes). Proteins 2007. © 2007 Wiley‐Liss, Inc.
Docking without docking: ISEARCH—prediction of interactions using known interfaces
Authors: Günther Stefan , May Patrick , Hoppe Andreas , Frömmel Cornelius , Preissner Robert 
Published: September 2007

AbstractThe increasing number of solved protein structures provides a solid number of interfaces, if protein–protein interactions, domain–domain contacts, and contacts between biological units are taken into account. An interface library gives us the opportunity to identify surface regions on a target molecule that are similar by local structure and residue composition. If both unbound components of a possible protein complex exhibit structural similarities to a known interface, the unbound structures can be superposed onto the known interfaces. The approach is accompanied by two mathematical problems. Protein surfaces have to be quickly screened by thousands of patches, and similarity has to be evaluated by a suitable scoring scheme. The used algorithm (NeedleHaystack) identifies similar patches within minutes. Structurally related sites are recognized even if only parts of the template patches are structurally related to the interface region. A successful prediction of the protein complex depends on a suitable template of the library. However, the performed tests indicate that interaction sites are identified even if the similarity is very low. The approach complements existing ab initio methods and provides valuable results on standard benchmark sets. Proteins 2007. © 2007 Wiley‐Liss, Inc.