bluuebunny/crossref_metadata_2025_split huggingface dataset:
Complete semi‐analytical treatment of weakly singular integrals on planar triangles via the direct evaluation method
Authors: Polimeridis Athanasios G. , Mosig Juan R. 
Published: March 2010

AbstractA complete semi‐analytical treatment of the four‐dimensional (4‐D) weakly singular integrals over coincident, edge adjacent and vertex adjacent triangles, arising in the Galerkin discretization of mixed potential integral equation formulations, is presented. The overall analysis is based on the direct evaluation method, utilizing a series of coordinate transformations, together with a re‐ordering of the integrations, in order to reduce the dimensionality of the original 4‐D weakly singular integrals into, respectively, 1‐D, 2‐D and 3‐D numerical integrations of smooth functions. The analytically obtained final formulas can be computed by using typical library routines for Gauss quadrature readily available in the literature. A comparison of the proposed method with singularity subtraction, singularity cancellation and fully numerical methods, often used to tackle the multi‐dimensional singular integrals evaluation problem, is provided through several numerical examples, which clearly highlights the superior accuracy and efficiency of the direct evaluation scheme. Copyright © 2010 John Wiley & Sons, Ltd.
Coupling BEM/TBEM and MFS for the simulation of transient conduction heat transfer
Authors: Tadeu António , Simões Nuno , Simões Inês 
Published: March 2010

AbstractThe coupling between the boundary element method (BEM)/the traction boundary element method (TBEM) and the method of fundamental solutions (MFS) is proposed for the transient analysis of conduction heat transfer in the presence of inclusions, thereby overcoming the limitations posed by each method. The full domain is divided into sub‐domains, which are modeled using the BEM/TBEM and the MFS, and the coupling of the sub‐domains is achieved by imposing the required boundary conditions.The accuracy of the proposed algorithms, using different combinations of BEM/TBEM and MFS formulations, is checked by comparing the resulting solutions against referenced solutions.The applicability of the proposed methodology is shown by simulating the thermal behavior of a solid ring incorporating a crack or a thin inclusion in its wall. The crack is assumed to have null thickness and does not allow diffusion of energy; hence, the heat fluxes are null along its boundary. The thin inclusion is modeled as filled with thermal insulating material. Copyright © 2010 John Wiley & Sons, Ltd.
Inspection model and correlation functions to assist in the correction of qualitative defects of injected parts
Authors: Chaves Miryam L. , Vizán Antonio , Márquez Juan J. , Ríos José 
Published: March 2010

AbstractTo perform quality inspection in the injection process is a complex task due to high number of defects that could occur in an injected part and the high number of process parameters that could produce them. Injection defects, in particular qualitative ones, are not a clear reference to determine correct process parameter value setting to produce good quality parts. Research results show that the occurrence of each injection defect could be caused by specific parameters with values above or below an optimal one. Although this information is a guide for the defect correction, the effective correction of qualitative defects with parameter modifications is very complex. This is due to the problems that arise when transforming a qualitative defect into a quantitative inspection. This article shows an inspection model to assist the qualitative defect intensity classification using defect behavior tendency curves. These curves have been deduced from generic analytical relationships established between injection defects and injection process parameters. Conducted tests allow validating the approach and its initial effectiveness. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Investigation of a strategy for well controlled inducement of microcellular and nanocellular morphologies in polymers
Authors: Janani Hamed , Famili M.H.N. 
Published: March 2010

AbstractThis study is an effort to modify conventional batch processes to be able to produce polymeric foams with high cell density and small cell size, which cannot be reached by conventional batch foaming processes. This has been attained by controlling the foaming temperature and controlled stabilization of the cellular structure. The method was tested for both with and without addition of nanosized particles in polymeric matrix. The desired morphologies were obtained using a novel apparatus with the capability of instantaneous pressure drop and controlling stabilization of the foam structure. The design of the said apparatus was based on the idea that in a foaming process, nucleation is the predominant mechanism that determines the final foam structure. The produced foam products have uniform structures without any unfoamed skin. Results show that the control of the foaming temperature and the cell stabilization are the predominant factors in adjustment of the final foam morphology. A wide range of microcellular structures with cell densities between 107 and 1012 bubbles/cm3 and average cell sizes of 500 nm–20 μm were produced. Foaming of polystyrene‐nano‐silica nano‐composites with the same method showed that nanoparticles act as nucleating agent and increase the cell density in the final foam products compared with that of neat polystyrene. POLYM. ENG. SCI., 50:1558–1570, 2010. © 2010 Society of Plastics Engineers
Preparation and characterization of chitosan/α‐zirconium phosphate nanocomposite films
Authors: Wu Haixia , Liu Changhua , Chen Jianguang , Yang Yajuan , Chen Yun 
Published: March 2010

AbstractNano‐fillers play an important role in the final structure and properties of nanocomposites. The objective of the work presented here was to prepare nanocomposite films of chitosan/α‐zirconium phosphate using a casting process, with α‐zirconium phosphate (α‐ZrP) as nano‐filler and chitosan as matrix. The effects of α‐ZrP on the structure and properties of the nanocomposites were investigated. X‐ray diffraction patterns showed that α‐ZrP crystals were intercalated by n‐butylamine. The results from scanning electron microscopy and transmission electron microscopy indicated that α‐ZrP could be uniformly dispersed in the chitosan matrix when α‐ZrP loading in the composites was less than 2 wt%. A strong interaction between α‐ZrP and chitosan formed during the film‐forming process. Tensile testing showed that the tensile strength and elongation at break of nanocomposite films achieved maximum values of 61.6 MPa and 58.1%, respectively, when α‐ZrP loading was 2 wt%. The parameter B calculated from tensile yield stress according to the Pukanszky model was used to estimate the interfacial interaction between the chitosan matrix and α‐ZrP. Films with a loading of 2 wt% α‐ZrP had the highest B value (3.2), indicating the strongest interfacial interaction. The moisture uptake of the nanocomposites was reduced with addition of α‐ZrP. It can be concluded that α‐ZrP as nano‐filler in a chitosan matrix can enhance the mechanical properties of nanocomposites due to the strong interactions between α‐ZrP and chitosan. Copyright © 2010 Society of Chemical Industry
Core–shell particles designed for toughening poly(vinyl chloride)
Authors: Chen Ming , Zhou Chao , Liu Zhenguo , Cao Chunlei , Liu Zhe , Yang Haidong , Zhang Huixuan 
Published: March 2010

AbstractA novel core–shell modifier (MOD) made up of polystyrene and poly(butyl acrylate) (PBA) grafted on a crosslinked styrene‐co‐butadiene core was synthesized by emulsion polymerization. This modifier was used for enhancing effectively the impact ductility of poly(vinyl chloride) (PVC) without losing its transparency. The effects of the MOD on the properties of PVC/MOD blends were explored. It was found that the butyl acrylate (BA) content of the MOD was an important factor affecting the properties of PVC/MOD blends. The Izod impact strength of these blends reached 1200 J m−1 when the MOD contained 40 wt% BA. The dispersion morphology of the MOD in the PVC matrix was investigated using transmission electron microscopy, with a uniform dispersion of the MOD with higher BA content being obtained. The toughening mechanism of PVC/MOD blends was also investigated. The presence of BA in the MOD enhanced the ductility of the PVC blends due to the increased amount of soft phase (PBA). The dispersion morphology indicated that the interfacial interaction between MOD particles and PVC matrix was improved due to the presence of PBA graft chain in the MOD. TEM of impact fracture samples showed that shear yielding of the PVC matrix and debonding of MOD particles were the major toughening mechanisms for the PVC/MOD blends. Copyright © 2010 Society of Chemical Industry
The dependence of morphology of solid polymer electrolyte membranes on transient salt type: effect of cation type
Authors: Esmaeili Majid , Madaeni Sayed S , Barzin Jalal 
Published: March 2010

AbstractThe structures of poly(N‐vinyl pyrrolidone) (PVP) and poly(ether sulfone) composite membranes were investigated with transient salt addition. The effects of type and concentration of AgNO3 and Cu(NO3)2 on membrane morphology were evaluated through attenuated total reflection Fourier transform infrared (ATR‐FTIR) spectroscopy, differential scanning calorimetry (DSC) and atomic force microscopy. Complex formation between carbonyl groups (on PVP chains) and Cu2+ or Ag+ decreases the strength of the carbonyl bond as evidenced through ATR‐FTIR spectroscopy. The results indicate that the copper salts create more powerful interactions than the silver salts in the polymer matrix. DSC experiments reveal that the glass transition temperature of polymeric films containing silver or copper cations is lower than that of the PVP reference film. Comparison of the thermograms of PVP + AgNO3 and PVP + Cu(NO3)2 shows that copper ions disrupt the polymer crystallinity more than silver ions. Therefore, DSC observations confirm the ATR‐FTIR results in the case of the strength of the complexes formed. A morphological analysis of membrane surfaces reveals the existence of electrostatic interactions in the polymeric membrane structure. This is a result of the addition of salt to the casting solution, wrinkling the polymer chains including the surface layer, and accordingly the surface of the facilitated transport membranes is rougher than the initial PVP membrane. Copyright © 2010 Society of Chemical Industry
Comparison of the performance of two affinity depletion spin filters for quantitative proteomics of CSF: Evaluation of sensitivity and reproducibility of CSF analysis using GeLC‐MS/MS and spectral counting
Authors: Fratantoni Silvina A. , Piersma Sander R. , Jimenez Connie R. 
Published: March 2010

AbstractPurpose: For biomarker discovery in cerebrospinal fluid (CSF), removal of major serum proteins is advantageous as more CSF proteins including brain‐derived proteins can be identified. Our goal was to create a reproducible discovery workflow with acceptable throughput that can identify 500–1000 CSF proteins in small volumes of CSF.Experimental design: In this study, we compared the performance of two multi‐affinity depletion methods in spin filter format: MARS Human 14 and Seppro‐IgY‐14. To this end, we analyzed depleted and bound CSF fractions isolated from 0.5 mL aliquots of the same CSF sample (n=3 per depletion method) by label‐free GeLC‐MS/MS‐based proteomics and normalized spectral counting.Results: The whole CSF dataset contained 884 proteins identified at high confidence. Depletion spin filter performance was assessed in terms of sensitivity and reproducibility of the CSF analysis. MARS and IgY‐14 spin filters yielded comparable reproducibility of protein identification (71–74%) and quantification (CV 17–18%) but a significant difference in the total number of identified CSF proteins (767 and 703 proteins, respectively).Conclusions and clinical relevance: The MARS filter compared to IgY‐14 filter provides a CSF analysis with enhanced proteome coverage. We anticipate that this enhanced sensitivity will facilitate biomarker discovery in early stages of cancer or neurological disease.
Crystal structures of truncated alphaA and alphaB crystallins reveal structural mechanisms of polydispersity important for eye lens function
Authors: Laganowsky Arthur , Benesch Justin L. P. , Landau Meytal , Ding Linlin , Sawaya Michael R. , Cascio Duilio , Huang Qingling , Robinson Carol V. , Horwitz Joseph , Eisenberg David 
Published: March 2010

AbstractSmall heat shock proteins alphaA and alphaB crystallin form highly polydisperse oligomers that frustrate protein aggregation, crystallization, and amyloid formation. Here, we present the crystal structures of truncated forms of bovine alphaA crystallin (AAC59–163) and human alphaB crystallin (ABC68–162), both containing the C‐terminal extension that functions in chaperone action and oligomeric assembly. In both structures, the C‐terminal extensions swap into neighboring molecules, creating runaway domain swaps. This interface, termed DS, enables crystallin polydispersity because the C‐terminal extension is palindromic and thereby allows the formation of equivalent residue interactions in both directions. That is, we observe that the extension binds in opposite directions at the DS interfaces of AAC59–163 and ABC68–162. A second dimeric interface, termed AP, also enables polydispersity by forming an antiparallel beta sheet with three distinct registration shifts. These two polymorphic interfaces enforce polydispersity of alpha crystallin. This evolved polydispersity suggests molecular mechanisms for chaperone action and for prevention of crystallization, both necessary for transparency of eye lenses.
Functional rules for lac repressor–operator associations and implications for protein–DNA interactions
Authors: Milk Leslie , Daber Robert , Lewis Mitchell 
Published: March 2010

AbstractThe Lac repressor has been used as a tool to understand protein–DNA recognition for many years. Recent experiments have demonstrated the ability of the Lac repressor to control gene expression in various eukaryotic systems, making the quest for an arsenal of protein–DNA binding partners desirable for potential therapeutic applications. Here, we present the results of the most exhaustive screen of Lac repressor‐DNA binding partners to date, resulting in the elucidation of functional rules for Lac–DNA binding. Even within the confines of a single protein–DNA scaffold, modes of binding of different protein–DNA partners are sufficiently diverse so as to prevent elucidation of generalized rules for recognition for a single protein, much less an entire protein family.
Similarities between Argonautes and the alpha‐sarcin‐like ribotoxins: Implications for microRNA action
Authors: Pichinuk Edward , Wreschner Daniel H. 
Published: March 2010

AbstractWe report structural, functional, and biochemical similarities between Argonautes, the effector proteins of RNA‐induced silencing complexes (RISCs), and alpha‐sarcin‐like ribotoxins. At the structural level, regions of similarity in the amino acid sequence are located in protein loops both in the ribotoxins and in the Argonautes. In ribotoxins, these protein loops confer specificity for a highly conserved segment of ribosomal RNA, the Sarcin‐Ricin‐Loop (SRL) that undergoes cleavage by the ribotoxin ribonuclease. This leads to suppression of translation. In addition to the structural similarity with ribotoxins, the Argonaute proteins (Ago) show both functional and biochemical parallels. Like the ribotoxins, the Agos exhibit ribonuclease activity and like the ribotoxins, translational suppression mediated by miRISC‐resident Ago is accompanied by intact polysomes. Furthermore, in both translationally suppressed systems, the puromycin reaction, reflecting correct translocation and peptidyl‐transferase activities, is unharmed. These findings support a mechanism for Ago‐miRISCs whereby regulated cleavage of ribosomal RNA leads to translational suppression.
Structural basis for the negative regulation of bacterial stress response by RseB
Authors: Kim Dong Young , Kwon Eunju , Choi JongKeun , Hwang Hye‐Yeon , Kim Kyeong Kyu 
Published: March 2010

AbstractThe σE‐dependent stress response in bacterial cells is initiated by the DegS‐ and RseP‐regulated intramembrane proteolysis of a membrane‐spanning antisigma factor, RseA. RseB binds to RseA and inhibits its sequential cleavage, thereby functioning as a negative modulator of this response. In the crystal structure of the periplasmic domain of RseA bound to RseB, the DegS cleavage site of RseA is unstructured, however, its P1 residue is buried in the hydrophobic pocket of RseB, which suggests that RseB binding blocks the access of DegS to the cleavage site.
Systemic action of novel neonicotinoid insecticide IPP‐10 and its effect on the feeding behaviour of Rhopalosiphum padi on wheat
Authors: Cui Li , Sun Lina , Shao Xusheng , Cao Yazhong , Yang Daibin , Li Zhong , Yuan Huizhu 
Published: March 2010

AbstractBACKGROUND: IPP‐10 is a novel neonicotinoid insecticide recently developed in China and has good activity against sucking insects. Studies were carried out to investigate the activity of IPP‐10 against Rhopalosiphum padi L.RESULTS: The results demonstrated that IPP‐10 had both contact and systemic activity, including acropetal and basipetal translocation in wheat vascular bundles. Starved R. padi were allowed to stay on wheat treated with a sublethal dose of IPP‐10. The results of studying their feeding behaviour from an electrical penetration graph (EPG) revealed a decrease in total time and bout duration of xylem and phloem ingestion, but the total time and bout duration of phloem salivation were significantly prolonged. The frequency (7.03 ± 0.49 Hz) of the xylem ingestion waveform produced by aphids on wheat treated with IPP‐10 was significantly lower than that of blank control aphids (8.20 ± 0.30 Hz). Consequently, aphids born on wheat treated with IPP‐10 were obviously lighter and less fecund than the control aphids.CONCLUSION: These tests indicated that IPP‐10 had both contact and systemic activity, with sublethal effects resulting in reduction in R. padi feeding behaviour, growth rate and fecundity. Copyright © 2010 Society of Chemical Industry
The action of herbicides on fatty acid biosynthesis and elongation in barley and cucumber
Authors: Yang Xueying , Guschina Irina A , Hurst Samantha , Wood Sophie , Langford Mike , Hawkes Tim , Harwood John L 
Published: March 2010

AbstractBACKGROUND: Herbicides that affect lipid metabolism have been used commercially for many years. Here, napropamide, diphenamid, dimethachlor and cafenstrole are compared; these have all been classified by the Herbicide Resistance Action Committee (HRAC) as K3 herbicides and inhibitors of cell division and/or synthesis of very‐long‐chain fatty acids (VLCFAs). In addition, spiro‐decanedione A and pinoxaden dione are compared as inhibitors of lipid synthesis through inhibition of acetyl‐CoA carboxylase (ACCase).RESULTS: Whereas the chloracetamide dimethachlor and the carboxyamide cafenstrole potently inhibited VLCFA synthesis in both barley and cucumber, the acetamides napropamide and diphenamid which are also classified as K3 herbicides and likewise the unclassified herbicide cinmethylin did not. The graminicide pinoxaden dione inhibited de novo fatty acid synthesis in barley, but not in cucumber, and correspondingly inhibited the plastid form of maize ACCase much more than the cytosolic form (IC50 values of 0.1 and 17 µM). By contrast, spiro‐decanedione A exhibited herbicidal effects not only on grasses but also on broad leaves, strongly inhibited maize cytosolic ACCase and inhibited synthesis of VLCFAs in cucumber.CONCLUSIONS: The acetamides napropamide and diphenamid, which do not inhibit VLCFA synthesis, should be classified separately from K3 herbicides that do. Pinoxaden dione and spiro‐decanedione A represent new classes of chemicals acting on plant lipid synthesis. Copyright © 2010 Society of Chemical Industry
First report of cyromazine resistance in a population of UK house fly (Musca domestica) associated with intensive livestock production
Authors: Bell Howard A , Robinson Katherine A , Weaver Robert J 
Published: March 2010

AbstractBACKGROUND: House fly control in livestock‐rearing facilities is heavily reliant on the use of the larvicide cyromazine. While extensive use of this compound has led to the development of resistance in several countries, no elevated tolerance has so far been reported from the United Kingdom.RESULTS: Tolerance to cyromazine in larvae derived from a field strain collected at an intensive pig unit was significantly elevated over that of insects taken from a susceptible laboratory strain. Resistance factors (RFs) of 2.9 and 2.4 were returned for assays initiated with eggs and neonate larvae respectively. The RF for field strain larvae exposed from neonate increased significantly to 3.9 and 5.6 following rounds of selection at 1.0 and then 1.5 mg kg−1 cyromazine.CONCLUSION: Low‐level resistance to cyromazine in UK house flies is reported here for the first time. The geographic extent of this resistance is unknown but, if widespread, may lead to control failures in the future, and indicates that careful stewardship of this compound in the United Kingdom is now required. © Crown copyright 2010. Reproduced with permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.
Structure–biological activity relationships in triterpenic saponins: the relative activity of protobassic acid and its derivatives against plant pathogenic fungi
Authors: Saha Supradip , Walia Suresh , Kumar Jitendra , Parmar Balraj S 
Published: March 2010

AbstractBACKGROUND: Triterpenic saponins from Sapindus mukorossi Gaertn. and Diploknema butyracea JF Gmelin were evaluated for in vitro antifungal activity against four phytopathogenic fungi. The study of the structure–antifungal activity relationships of protobassic acid saponins was widened by including semi‐synthetic derivatives.RESULTS: Diploknema butyracea saponins exhibited significant antifungal activity against three fungi (ED50 230–455 µg mL−1), whereas S. mukorossi saponin was effective against two fungi (ED50 181–407 µg mL−1). The n‐butanol extract after preparative HPLC separation provided two saponins from D. butyracea saponin mixture: 3‐O‐[β‐D‐glucopyarnosyl‐β‐D‐glucopyranosyl]‐16‐α‐hydroxyprotobassic acid‐28‐O‐[arabinopyranosyl‐glucopyranosyl‐xylopyranosyl]‐arabinopyranoside (MI‐I), and 3‐O‐β‐D‐glucopyranosyl‐glucopyranosyl‐glucopyranosyl‐16‐α‐hydroxyprotobassic acid‐28‐O‐[arabinopyranosyl‐xylopyranosyl‐arabinopyranosyl]‐apiofuranoside (MI‐III). The single saponin extracted from S. mukorossi saponin mixture was identified as 3‐O‐[O‐acetyl‐β‐D‐xylopyranosyl‐β‐D‐arabinopyranosyl‐β‐D‐rhamnopyranosyl] hederagenin‐28‐O[β‐D‐glucopyranosyl‐β‐D‐glucopyranosyl‐β‐D‐rhamnopyranosyl] ester (SM‐I). Monodesmosides resulting from the partial degradation of hederagenin and hydroxyprotobassic acid bisdesmosides exhibited significant reduction in antifungal effect. Further removal of sugar moiety yielded complete loss in activity. The antifungal activity of the triterpenic saponins was associated with their aglycone moieties, and esterification of the hydroxyl group led to change in antifungal activity.CONCLUSION: Sapindus mukorossi saponin, which is effective against Rhizoctonia bataticola (Taub.) Briton Jones and Sclerotium rolfsii Sacc., can be exploited for the development of a natural fungicide. A sugar moiety is a prerequisite for the antifungal activity of triterpenic saponin. Copyright © 2010 Society of Chemical Industry