bluuebunny/crossref_metadata_2025_split huggingface dataset:
Poly(lactic acid)/organoclay nanocomposites: Thermal, rheological properties and foam processing
Authors: Di Yingwei , Iannace Salvatore , Maio Ernesto Di , Nicolais Luigi 
Published: February 2005

AbstractIn this study, polymer nanocomposites based on poly(lactic acid) (PLA) and organically modified layered silicates (organoclay) were prepared by melt mixing in an internal mixer. The exfoliation of organoclay could be attributed to the interaction between the organoclay and PLA molecules and shearing force during mixing. The exfoliated organoclay layers acted as nucleating agents at low content and as the organoclay content increased they became physical hindrance to the chain mobility of PLA. The thermal dynamic mechanical moduli of nanocomposites were also improved by the exfoliation of organoclay; however, the improvement was reduced at high organoclay content. The dynamic rheological studies show that the nanocomposites have higher viscosity and more pronounced elastic properties than pure PLA. Both storage and loss moduli increased with silicate loading at all frequencies and showed nonterminal behavior at low frequencies. The nanocomposites and PLA were then foamed by using the mixture of CO2 and N2 as blowing agent in a batch foaming process. Compared with PLA foam, the nanocomposite foams exhibited reduced cell size and increased cell density at very low organoclay content. With the increase of organoclay content, the cell size was decreased and both cell density and foam density were increased. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 689–698, 2005
Phase transitions in segmented polyesterurethane–DMSO–water systems
Authors: Heijkants R. G. J. C. , Van Calck R. V. , De Groot J. H. , Pennings A. J. , Schouten A. J. 
Published: February 2005

AbstractThe phase separation processes occurring in polyurethane/DMSO/water mixtures were studied using DSC and cloud point measurements. It is demonstrated that liquid–liquid demixing occurs in ternary solutions of segmented polyesterurethanes at sufficiently high water concentrations. It is also shown that the hard segment can crystallize from solution when cooled to room temperature; while if the mixture is cooled to sufficiently low temperatures, DMSO partially freezes, which also induces crystallization of the soft segment. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 716–723, 2005
Thermal transitions and structure of epoxy networks based on α, ω‐diamino terminated poly(propylene oxide)‐block‐poly(ethylene oxide)‐block‐poly(propylene oxide) swollen in water
Authors: Krakovský Ivan , Sánchez Manuel Salmerón 
Published: February 2005

AbstractThermal transitions in epoxy networks prepared by reaction of α, ω‐diamino terminated poly(propylene oxide)‐block‐poly(ethylene oxide)‐block‐poly(propylene oxide) and diglycidyl ether of brominated Bisphenol A, swollen in water, were studied by differential scanning calorimetry (DSC) in a broad temperature range (from −100 °C to 20 °C). Networks of two different values of initial molar ratio of amino and epoxy groups were prepared, r (r = 1.00, 2.00), and swollen with different amounts of water up to equilibrium concentration values. The qualitatively different kinds of experimental thermograms have been obtained for two networks and classified according to the amount of water in the sample on the basis of the phase diagram of the system. Also, the concentration dependence of the curves in this diagram (glass transition, melting, and crystallization) as well as the fraction of noncrystallizable water supply some information about the morphology of the system. In this sense, the existence of a microphase separated structure of swollen networks is suggested. The structure consists of hydrophilic and hydrophobic domains and depends on the initial molar ratio of the reactive groups. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 699–708, 2005
MM/PBSA analysis of molecular dynamics simulations of bovine β‐lactoglobulin: Free energy gradients in conformational transitions?
Authors: Fogolari Federico , Moroni Elisabetta , Wojciechowski Marcin , Baginski Maciej , Ragona Laura , Molinari Henriette 
Published: February 2005

AbstractThe pH‐driven opening and closure of β‐lactoglobulin EF loop, acting as a lid and closing the internal cavity of the protein, has been studied by molecular dynamics (MD) simulations and free energy calculations based on molecular mechanics/Poisson–Boltzmann (PB) solvent‐accessible surface area (MM/PBSA) methodology. The forms above and below the transition pH differ presumably only in the protonation state of residue Glu89. MM/PBSA calculations are able to reproduce qualitatively the thermodynamics of the transition. The analysis of MD simulations using a combination of MM/PBSA methodology and the colony energy approach is able to highlight the driving forces implied in the transition. The analysis suggests that global rearrangements take place before the equilibrium local conformation is reached. This conclusion may bear general relevance to conformational transitions in all lipocalins and proteins in general. Proteins 2005. © 2005 Wiley‐Liss, Inc.
Preservation of cold‐stored guavas influenced by package materials
Authors: Jacomino Angelo Pedro , Bron Ilana Urbano , Sarantópoulos Claire Isabel Grígoli de Luca , Sigrist José Maria Monteiro 
Published: February 2005

AbstractThe objective of this study was to evaluate the influence of package materials on the preservation of cold‐stored ‘Kumagai’ guavas. The treatments were: PO2, co‐extruded polyolephinic film with gas injection (5% O2/5% CO2/N2); PO3, co‐extruded polyolephinic film with gas injection (5% O2/5% CO2/N2); LDPE, linear low density polyethylene film; LDPE‐gas, linear low density polyethylene film with gas injection (3% O2/8% CO2/N2); PVC, polyvinylchloride stretch film; PO1, co‐extruded polyolephinic film and control: non‐packaged guavas. Guavas were stored at 10 ± 1°C/80–90% RH for 21 days, and then transferred to room temperature. Gas composition within the package headspace was analysed during storage and the physical and chemical characteristics of the guavas were evaluated daily during ripening. The modified atmosphere provided by PO1 film was insufficient to promote the benefit of senescence control. Although PVC provided an atmosphere close to that recommended, it did not preserve the colour and pulp firmness. PO2, PO3, LDPE and LDPE‐gas retarded the senescence process of the guavas during 21 days at 10°C plus 2 days at room temperature, but harmed the normal ripening of guavas in some aspects. This can be explained by reduced O2 and elevated CO2 levels within these four packages. None of the packages influenced the titratable acidity and the soluble solids, but they did harm ascorbic acid synthesis. Copyright © 2005 John Wiley &amp; Sons, Ltd.
Investigation of copper patinas using ion beam analysis and scanning electron microscopy
Authors: Noli F. , Misaelides P. , Pavlidou E. , Kokkoris M. 
Published: January 2005

AbstractIon beam analysis (IBA) techniques were applied successfully to the investigation of non‐corroded and artificially corroded patina layers grown on copper substrates in order to explore their potential use in the study of degradation phenomena of copper and copper alloys subjected to chemical treatment and exposed to selected environmental conditions. Rutherford backscattering spectroscopy (RBS) with deuterons as projectiles and the nuclear reactions 16O(d,p)17O and 32S(p,p′γ)32S were applied to the investigation of the depth distribution of oxygen and sulphur in near‐surface layers of synthetic patina consisting of mineral phases corresponding to chalcanthite as well as to cuprite + chalcanthite and antlerite + brochantite + chalcanthite. Electrochemical techniques (potentiodynamic polarization and cyclic voltammetry in 0.5 M Na2SO4) were used for artificial acceleration and study of the corrosion processes, and scanning electron microscopy (SEM/EDS) was used for examination of the surface morphology of the samples. A patinated roof sample from the Vienna Hofburg also was investigated using the same techniques. The measurement showed that IBA can provide valuable information for the study of patina near‐surface layers of thickness up to a few micrometres and indicated that cuprite was the mineral phase primarily formed on the copper substrates and the main component of the interface between the patina layer and the metallic substrate. The investigated copper patinas looked rather heterogeneous and were characterized by high porosity. Mixed patinas exhibited considerable stability to further corrosive attack. Copyright © 2005 John Wiley & Sons, Ltd.
Illustration of the interface between N2/CO2 plasmas and polystyrene surface
Authors: Wang Meng‐Jiy , Chang You‐Im , Poncin‐Epaillard F. 
Published: January 2005

AbstractPlasma treatment results in the surface modification of materials and its effects generally can be examined by surface analytical methods such as contact angle measurement, XPS, atomic force microscopy, etc. In situ studies such as mass spectrometry and optical emission spectroscopy usually have been employed to analyse the reactive species in the plasma phase and provide information related to the mechanism of plasma treatment processes. This work shows that in situ studies not only verify the results of plasma treatment but also can provide a more effective method to analyse the mechanism of the plasma/surface interaction process, such as identification of the reactive species leading to functionalization of the surface and the species resulting from surface degradation. These real‐time diagnostic methods confirm the suitable treatment conditions for both N2 and CO2 plasmas for an applied power range of 20–40 W and a flow rate of 5–10 sccm, as shown previously with ex situ surface analyses. Copyright © 2005 John Wiley & Sons, Ltd.
Study of SHIP‐binding cell surface proteins suggests c‐kit as a SHIP‐interacting receptor in mast cells
Authors: Ott Vanessa L. , Moffitt Lisa A. , Cambier John C. 
Published: January 2005

AbstractMast cells play a central role in a wide range of immunological and pathological processes, but are most noted for their role in IgE‐dependent allergic responses. Aggregation of the high‐affinity receptor for IgE, FcηRI, stimulates mast cell degranulation, production of lipid mediators, and the synthesis and secretion of cytokines and chemokines. FcηRI‐induced mast cell activation is subject to regulation by inhibitory receptors that transduce intracellular signals via associating phosphatases. The inositol 5‐phosphatase SHIP has been implicated in FcγIIB‐mediated inhibition of FcηRI‐induced mast cell activation. However, SHIP also negatively regulates FcηRI signaling independent of FcγRIIB, suggesting the existence of additional receptors that mediate SHIP recruitment into sites where it mediates its inhibitory function. Here we show that SHIP associates with numerous phosphoproteins from pervanadate‐stimulated mast cells. Based on their sensitivity to PNGase F treatment and cell surface biotinylation, some of these molecules may represent cell surface receptors. A prominent 120−130 kDa SHIP‐binding phosphoprotein was identified in untreated RBL‐2H3 cells and BMMC stimulated with stem cell factor. Based on its molecular weight, sensitivity to PNGase F, and reactivity with an anti‐c‐kit antibody, we conclude that this phosphoprotein is c‐kit. Furthermore, tyrosine phosphorylation of SHIP is enhanced following SCF stimulation. Taken together, these data suggest that SHIP may function as a negative regulator of SCF signaling via direct association with phosphorylated c‐kit.
Effects of thematic‐based, hands‐on science teaching versus a textbook approach for students with disabilities
Authors: McCarthy Cheryl B. 
Published: January 2005

AbstractInstitutions of higher education, states, and local K–12 districts have been challenged to improve math and science education for our nation's students. In the past few years, there has been renewed interest in inquiry‐based, activity‐oriented instruction in science for students with disabilities. Yet, there still exists the need for further empirical evidence to support instructional improvements for students with more involved emotional and behavioral disabilities. This study describes a program in which 18 middle school students with serious emotional disturbances were instructed, over the course of 8 weeks, on “Matter” by two different instructional approaches. Students in one classroom received a traditional textbook approach to science content, whereas students in another classroom received science instruction by a hands‐on, thematic approach. Over the course of instruction, data were collected regarding students' behavior and achievement. Results indicate that, overall, students in the hands‐on instructional program performed significantly better than the students in the textbook program on two of three measures of science achievement, a hands‐on assessment and a short‐answer test. The students did not differ on a multiple‐choice format test. With regard to behavior, there were no significant differences in behavioral problems found between the two groups of students over the course of the study. Findings are discussed in relation to instructional implications for students with disabilities in the science classroom. © 2005 Wiley Periodicals, Inc. J Res Sci Teach 42: 245–263, 2005
Transcriptional regulation of the uptake [NiFe]hydrogenase genes in Rhodobacter capsulatus
Authors: Vignais P.M. , Elsen S. , Colbeau A. 
Published: February 2005

Transcription of the hupSL genes, which encode the uptake [NiFe]hydrogenase of Rhodobacter capsulatus, is specifically activated by H2. Three proteins are involved, namely the H2-sensor HupUV, the histidine kinase HupT and the transcriptional activator HupR. hupT and hupUV mutants have the same phenotype, i.e. an increased level of hupSL expression (assayed by phupS::lacZ fusion) in the absence of H2; they negatively control hupSL gene expression. HupT can autophosphorylate its conserved His217, and in vitro phosphotransfer to Asp54 of its cognate response regulator, HupR, was demonstrated. The non-phosphorylated form of HupR binds to an enhancer site (5′-TTG-N5-CAA) of phupS localized at −162/−152 nt and requires integration host factor to activate fully hupSL transcription. HupUV is an O2-insensitive [NiFe]hydrogenase, which interacts with HupT to regulate the phosphorylation state of HupT in response to H2 availability. The N-terminal domain of HupT, encompassing the PAS domain, is required for interaction with HupUV. This interaction with HupT, leading to the formation of a (HupT)2–(HupUV)2 complex, is weakened in the presence of H2, but incubation of HupUV with H2 has no effect on the stability of the heterodimer/tetramer, HupUV–(HupUV)2, equilibrium. HupSL biosynthesis is also under the control of the global two-component regulatory system RegB/RegA, which controls gene expression in response to redox. RegA binds to a site close to the −35 promoter recognition site and to a site overlapping the integration host factor DNA-binding site (5′-TCACACACCATTG, centred at −87 nt) and acts as a repressor.
Molecular characterization of uptake hydrogenase in Frankia
Authors: Leul M. , Mattsson U. , Sellstedt A. 
Published: February 2005

A molecular characterization of uptake hydrogenase in Frankia was performed by using two-dimensional gel electrophoresis, matrix-assisted laser-desorption ionization–time-of-flight mass spectrometry, PCR amplification and Southern blotting. A polypeptide of approx. 60 kDa was recognized in Frankia UGL011102, AVCI1 and KB5 on the two-dimensional gel by blotting with Ralstonia eutropha (Hox G) antibody. Further analysis by MS resulted in a peptide ‘fingerprint’, which was similar to the membrane-bound hydrogenase 2 large subunit (HYD2) in Escherichia coli. In addition, a 127 bp PCR fragment could also be amplified from Frankia AVCI1, which gave a 76% similarity with the large subunit of hydrogenase in, e.g., Azotobacter chrococcum, Bradyrhizobium japonicum and Rhizobium leguminosarum. Although immunological similarity between the small subunit of Frankia hydrogenase and that of other organisms has not yet been found, a PCR product of 500 bp could be amplified from the local source of Frankia, the analysis of which gave 69 and 67% identity with the small subunit of hydrogenases in B. japonicum and R. leguminosarum respectively. A Southern-blot analysis further indicated evidence for the presence of the small hydrogenase subunit in other Frankia strains, i.e. KB5, AvcI1 and CcI3.
Use of molecular hydrogen as an energy substrate by human pathogenic bacteria
Authors: Maier R.J. 
Published: February 2005

Molecular hydrogen is produced as a fermentation by-product in the large intestine of animals and its production can be correlated with the digestibility of the carbohydrates consumed. Pathogenic Helicobacter species (Helicobacter pylori and H. hepaticus) have the ability to use H2 through a respiratory hydrogenase, and it was demonstrated that the gas is present in the tissues colonized by these pathogens (the stomach and the liver respectively of live animals). Mutant strains of H. pylori unable to use H2 are deficient in colonizing mice compared with the parent strain. On the basis of available annotated gene sequence information, the enteric pathogen Salmonella, like other enteric bacteria, contains three putative membrane-associated H2-using hydrogenase enzymes. From the analysis of gene-targeted mutants it is concluded that each of the three membrane-bound hydrogenases of Salmonella enterica serovar Typhimurium are coupled with an H2-oxidizing respiratory pathway. From microelectrode probe measurements on live mice, H2 could be detected at approx. 50 μM levels within the tissues (liver and spleen), which are colonized by Salmonella. The half-saturation affinity of whole cells of these pathogens for H2 is much less than this, so it is expected that the (H2-utilizing) hydrogenase enzymes be saturated with the reducing substrate in vivo. All three enteric NiFe hydrogenase enzymes contribute to virulence of the bacterium in a typhoid fever-mouse model, and the combined removal of all three hydrogenases resulted in a strain that is avirulent and (in contrast with the parent strain) one that is not able to pass the intestinal tract to invade liver or spleen tissue. It is proposed that H2 utilization and specifically its oxidation, coupled with a respiratory pathway, is required for energy production to permit growth and maintain efficient virulence of a number of pathogenic bacteria during infection of animals. These would be expected to include the Campylobacter jejuni, a bacterium closely related to Helicobacter, as well as many enteric bacteria (Escherichia coli, Shigella and Yersinia species).
Amyloplasts and Vacuolar Membrane Dynamics in the Living Graviperceptive Cell of the Arabidopsis Inflorescence Stem
Authors: Saito Chieko , Morita Miyo T. , Kato Takehide , Tasaka Masao 
Published: February 2005

AbstractWe developed an adequate method for the in vivo analysis of organelle dynamics in the gravity-perceptive cell (endodermis) of the Arabidopsis thaliana inflorescence stem, revealing behavior of amyloplasts and vacuolar membranes in those cells. Amyloplasts in the endodermis showed saltatory movements even before gravistimulation by reorientation, and these movements were confirmed as microfilament dependent. From our quantitative analysis in the wild type, the gravity-oriented movement of amyloplasts mainly occurred during 0 to 3 min after gravistimulation by reorientation, supporting findings from our previous physiological study. Even after microfilament disruption, the gravity-oriented movement of amyloplasts remained. By contrast, in zig/sgr4 mutants, where a SNARE molecule functioning in vacuole biogenesis has been disrupted, the movement of amyloplasts in the endodermis is severely restricted both before and after gravistimulation by reorientation. Here, we describe vacuolar membrane behavior in these cells in the wild-type, actin filament–disrupted, and zig/sgr4 mutants and discuss its putatively important features for the perception of gravity. We also discuss the data on the two kinds of movements of amyloplasts that may play an important role in gravitropism: (1) the leading edge amyloplasts and (2) the en mass movement of amyloplasts.
Do Americans Trust Other Nations? A Panel Study*
Authors: Brewer Paul R. , Aday Sean , Gross Kimberly 
Published: February 2005

Objectives. This study examines Americans' generalized beliefs about how much the United States can trust other nations, as well as changes over time in such beliefs.Methods. We analyze original panel survey data collected in 2001 and 2002.Results. Although only a minority of panel respondents expressed generalized trust in other nations immediately after the terrorist attacks of September 11, 2001, even fewer expressed such trust when reinterviewed almost a year later. Social trust, political trust, and party loyalties predicted individual‐level change in this form of trust from 2001 to 2002.Conclusions. Declining trust in other nations may have important implications for public opinion and, ultimately, public policy regarding world affairs.
O Other, Where Art Thou? Support for Multiparty Politics in the United States*
Authors: Donovan Todd , Parry Janine A. , Bowler Shaun 
Published: February 2005

Objective.We test hypotheses about support for multiparty politics in the United States. We expect that individual‐level attitudes and state‐level partisan context determine who supports having more parties.Methods.Survey data are used to model attitudes about having additional parties to challenge Democrats and Republicans.Results.Self‐identified partisans are opposed to additional parties, but independents who “lean” toward a major party are most supportive. Independents who say they are closer to Democrats, as well as independents who say they are closer to Republicans, tend to support having new parties. The latter effect is contingent on a state's partisan context. Independents closer to Republicans are most receptive to additional parties in states where fewer conservative representatives are elected.Conclusions.Support for multiparty‐ism among “leaning” independents challenges our understanding of how they may be similar to partisan identifiers, and illustrates that a base for new parties may exist in the “mainstream” public if electoral rules were changed.
Religion and Abortion Attitudes Among U.S. Hispanics: Findings from the 1990 Latino National Political Survey*
Authors: Ellison Christopher G. , Echevarría Samuel , Smith Brad 
Published: February 2005

Objective. The goal of this article is to examine the relationship between religious involvement, gauged mainly in terms of affiliation and frequency of attendance at services, and abortion attitudes among three major Hispanic subgroups: Mexican Americans, Puerto Ricans, and Cuban Americans.Method. The study analyzes data from the Latino National Political Survey, a sample of over 2,700 U.S. Hispanics completed in 1990.Results. Committed (i.e., regularly attending) Hispanic Protestants, most of whom belong to conservative groups, are more strongly pro‐life than any other segment of the Latino population, and are much more likely than others to support a total abortion ban. Committed Catholics also tend to hold pro‐life views, but they are relatively more likely to endorse an abortion ban that includes exceptions for rape, incest, and threats to the mother's life. Less devoted Catholics and Protestants generally do not differ from religiously unaffiliated Hispanics in their abortion views. There are also modest variations in the links between religious involvement and abortion attitudes across the three Latino subgroups.Conclusion. Religious factors are highly important predictors of Hispanics' preferences regarding abortion policies. Contrary to some previous discussions, it is committed Protestants, more so than Catholics, who are the staunchest opponents of abortion in the Latino population.