bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative studies of rheological properties of polyacrylamide and partially hydrolyzed polyacrylamide solutions
Authors: Lewandowska Katarzyna 
Published: November 2006

AbstractThe present work is concerned with experimental results of rheological characteristics of polyacrylamide (PAM) and of partially hydrolyzed polyacrylamide (HPAM) (degree of hydrolysis up to 80%) in aqueous and aqueous/sodium chloride solutions with changing experimental conditions such as polymer concentration, temperature, solvent quality, and shear rate applied. It has been observed that the all‐aqueous and aqueous/NaCl solution of PAM and of HPAM exhibited the non‐Newtonian behavior with shear‐thinning and shear‐thickening areas. The onset of shear‐thickening at $\dot{\rm \gamma}=\dot{\rm \gamma}_c$ depends mainly on the degree of HPAM hydrolysis, as well as on solution concentration, temperature, solvent quality, and polymer molecular weight. Rheological parameters from power law (Ostwald de Waele model) and activation energy of viscous flow (Ea) are determined and discussed. The changes in apparent shear viscosity during aging of solutions of PAM and HPAM are also described. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2235–2241, 2007
Polymer electrolytes based on poly(ethylene glycol) and cyanoresin
Authors: Oh Kyung Wha , Choi Ji Hyoung , Kim Seong Hun 
Published: November 2006

AbstractPolymer electrolytes based on a mixed polymer matrix consisting of poly(ethylene glycol) (PEG) and cyanoresins with lithium salt and plasticizer were prepared with an in situ blending process to improve both the mechanical properties and the ionic conductivity (σ). The PEG/lithium perchlorate (LiClO4) complexes, including blends of cyanoethyl pullulan (CRS) and cyanoethyl poly(vinyl alcohol) (CRV), exhibited higher σ's than a simple PEG/LiClO4 complex when the blend compositions of CRS/CRV were 5 : 5 or 3 : 7 or than CRV alone. When the CRS/CRV blend was compared with a copolymer of cyanoethyl pullulan and cyanoethyl poly(vinyl alcohol) (CRM) in the same molar ratio, the σ values of the polymer electrolytes containing the CRM copolymer series were slightly higher than those of the CRS/CRV blends containing PEG/LiClO4 complexes. Moreover, the addition of cyanoresin to PEG/LiClO4/(ethylene carbonate–propylene carbonate) polymer electrolytes provided better thermal stability and dynamic mechanical properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2402–2408, 2007
Silver–polyimide nanocomposite membranes: Macromolecular‐matrix‐mediated metallization of an aromatic, fluorinated polyimide yielding highly reflective films at low metal concentrations
Authors: Davis Luke M. , Thompson D. Scott , Dean C. J. , Pevzner M. , Scott J. L. , Broadwater S. T. , Thompson D. W. , Southward R. E. 
Published: November 2006

AbstractHighly reflective, surface‐metalized, flexible polyimide films were prepared by the incorporation of a soluble silver‐ion complex, (hexafluoroacetylacetonato)silver(I) (AgHFA), into dimethylacetamide solutions of poly(amic acid) prepared from 2,2‐bis(3,4‐dicarboxyphenyl)hexafluoropropane dianhydride and 2,2‐bis[4‐(4‐aminophenoxy)phenyl]hexafluoropropane. The thermal curing of solution‐cast silver(I)–poly(amic acid) films to 300°C led to cycloimidization of the amic acid with concomitant silver(I) reduction and the formation of a reflective, air‐side‐silvered surface at very low (2 wt % and 0.3 vol %) silver concentrations. The reflective surface evolved only when the cure temperature reached about 275°C, although X‐ray diffraction showed metallic silver in the hybrid film by 200°C. After a maximum specular reflectivity greater than 80% was achieved for the 2 wt % silver film, the specular reflectivity diminished sharply with further heating at a constant temperature of 300°C. Incorporating the AgHFA complex into the soluble, fully imidized form of poly{(1,3‐dihydro‐1,3‐dioxo‐2H‐isoindole‐2,5‐diyl)[2,2,2‐trifluoro‐1‐(trifluoromethyl)ethylidene](1,3‐dihydro‐1,3‐dioxo‐2H‐isoindole‐5,2‐diyl)‐1,4‐phenyleneoxy‐1,4‐phenylene[2,2,2‐trifluoro‐1‐(trifluoromethyl)ethylidene]‐1,4‐phenyleneoxy‐1,4‐phenylene} gave films that were 25% less reflective than those beginning with poly(amic acid). Though highly reflective, the films were not electrically conductive. The metalized membranes were thermally stable and maintained mechanical properties similar to those of the parent polyimide. Transmission electron microscopy revealed an air‐side, near‐surface layer of silver that was about 40 nm thick; the interior of the film had well‐dispersed metal particles with diameters mostly less than 2 nm. The near‐surface silver layer maintained its integrity because of physical entrapment of the metal nanoparticles beneath a thin layer of polyimide; that is, the practical adhesion of the metal layer was good. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2409–2418, 2007
Isoelectric pH of polyamide–epichlorohydrin modified soy protein improved water resistance and adhesion properties
Authors: Zhong Zhikai , Sun XiuZhi Susan , Wang Donghai 
Published: November 2006

AbstractProtein macromolecules derived from plants have been considered as alternative resources for various applications, including adhesives, films, rubbers, and biocomposites. Plant protein polymers are pH sensitive and need to be modified to meet application performance. This study demonstrated interactions between polyamide–epichlorohydrin (PAE) and soy protein as affected by pH and temperature. PAE and soy protein molecules formed reversible ionic complexes at room temperature at a pH range of 4–9. The complexation interactions acted as physical crosslinking, which stabilized the soy protein structure and increased its denaturation temperature and enthalpy. The viscosity of adhesives derived from the interaction of PAE and soy protein was affected significantly by the complexation formation, denaturation, and pH. The complexation interactions improved the adhesion properties of the PAE/modified soy protein. pH also played an important role in the adhesion performance, which was attributed to the pH dependence of the protein conformation and PAE/soy protein complexation interactions. © 2006 Wiley Periodicals, Inc. J Appl PolymSci 103: 2261–2270, 2007
Environmentally benign precipitation copolymerization of methacrylate ester and styrene to make polymeric microspheres in supercritical carbon dioxide
Authors: Zhang Donghui , Mishima Kenji , Matsuyama Kiyoshi , Zhou Li , Zhang Shubiao 
Published: November 2006

AbstractThe polymeric microspheres were synthesized by the precipitation copolymerization of glycidyl methacrylate (GMA) with methacrylic acid(MAA) or 2‐hydoxyethyl methacrylate (2‐HEMA) containing styrene (ST) in SC‐CO2. Scanning electron microscopy (SEM) showed that the products were spherical microparticles, with the addition of MAA and/or 2‐HEMA as the monomer, with diameter of 0.2–2 μm. The effects of copolymerization pressure, temperature, and ratios of GMA/MAA, ST, and/or GMA/2‐HEMA, on the particle size and morphology were investigated in detail. A new experiment setup is proposed for the large amount of production, based on the rule of lower monomer concentration, more stable system, and better use of the present polymerization apparatus. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2425–2431, 2007
Temporal analysis of a very large topically categorized Web query log
Authors: Beitzel Steven M. , Jensen Eric C. , Chowdhury Abdur , Frieder Ophir , Grossman David 
Published: November 2006

AbstractThe authors review a log of billions of Web queries that constituted the total query traffic for a 6‐month period of a general‐purpose commercial Web search service. Previously, query logs were studied from a single, cumulative view. In contrast, this study builds on the authors' previous work, which showed changes in popularity and uniqueness of topically categorized queries across the hours in a day. To further their analysis, they examine query traffic on a daily, weekly, and monthly basis by matching it against lists of queries that have been topically precategorized by human editors. These lists represent 13% of the query traffic. They show that query traffic from particular topical categories differs both from the query stream as a whole and from other categories. Additionally, they show that certain categories of queries trend differently over varying periods. The authors key contribution is twofold: They outline a method for studying both the static and topical properties of a very large query log over varying periods, and they identify and examine topical trends that may provide valuable insight for improving both retrieval effectiveness and efficiency.
Exploratory synthesis of peptide–α‐thioester segments spanning the polypeptide sequence of the δ‐opioid receptor, a G protein‐coupled receptor
Authors: Johnson Erik C. B. , Kent Stephen B. H. 
Published: November 2006

AbstractWe have decided to use the δ‐opioid receptor (372 residues) as a model system to develop methods for the total chemical synthesis of G protein‐coupled receptors. The most important feature of this receptor from a chemical synthesis perspective is the wealth of cysteines spread throughout its sequence, which are required for native chemical ligation. A total of 13 cysteines are located in the the δ‐opioid receptor polypetide chain in both loop and putative transmembrane (TM) regions. We envisioned a synthesis of the polypeptide that would make use of peptide–α‐thioesters ranging from 37 to 63 residues in length. Here, we report data from an exploratory synthesis of such a set of peptide–α‐thioesters. For all seven peptides, the crude material ∼ 30 residues into the synthesis was sufficiently homogeneous to make isolation and purification straightforward. Extension of the peptides to between 40 and 50 residues in length generally produced a significant decrease in the quality of the crude products, although in most cases, we judged that high purity peptides could probably be isolated. By 60 residues, however, the crude peptide product mixtures are probably too heterogeneous to purify to homogeneity by reversed‐phase HPLC. In general, δ‐opioid receptor peptides with a single predicted TM domain were sufficiently soluble to handle postcleavage and to analyze by reversed‐phase HPLC, whereas 1.5 TM domains rendered the peptides too hydrophobic to handle or analyze by standard protocols. Given the challenges of chain assembly, handling, and purification of these peptides, a synthetic strategy that uses ∼ 12 or 13 shorter peptide segments of 20–40 residues each is probably a more feasible approach. © 2006 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 88: 340–349, 2007.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Kappa opioid receptors in the rostral ventromedial medulla of male and female rats
Authors: Drake Carrie T. , De Oliveira Andrew X. , Harris Jonathan A. , Connor Denise M. , Winkler Clayton W. , Aicher Sue A. 
Published: November 2006

AbstractKappa opioid receptor (KOR) ligands alter nociceptive responses when applied to the rostral ventromedial medulla (RVM). However, the effects of kappa opioid receptor ligands are distinct in males and females. The present study examined the distribution of kappa opioid receptor immunoreactivity in the RVM of male and female rats. KOR immunoreactivity was found at pre‐ and postsynaptic sites within the RVM of both sexes. The most common KOR‐immunoreactive (KOR‐ir) neuronal structures were unmyelinated axons, followed by axon terminals, dendrites, and somata. Different proportions of KOR‐ir axon terminals and dendrites were found in females at different estrous stages. Specifically, dendrites containing KOR immunoreactivity were less abundant in proestrus females compared with estrus females and showed a trend toward being less abundant in males, suggesting that KOR ligands applied to the RVM may be less potent in proestrus females. These findings suggest that the distribution of KORs in the RVM may be influenced by reproductive hormone levels. We also found KOR immunoreactivity in many spinally projecting neurons within the RVM of female rats. These findings are consistent with the hypothesis that KOR ligands influence nociceptive behaviors by altering the activity of specific populations of neurons within the RVM. The abundance of KOR in axons and axon terminals in RVM indicates a substantial role for presynaptic effects of KOR ligands through pathways that have not been clearly delineated. Altering the balance between pre‐ and postsynaptic receptive sites may underlie differences in the effects of KOR agonists on nociceptive responses in males and females. J. Comp. Neurol. 500:465–476, 2007. © 2006 Wiley‐Liss, Inc.
Selective enrichment of DJ‐1 protein in primate striatal neuronal processes: Implications for Parkinson's disease
Authors: Olzmann James A. , Bordelon Jill R. , Muly E. Chris , Rees Howard D. , Levey Allan I. , Li Lian , Chin Lih‐Shen 
Published: November 2006

AbstractMutations in DJ‐1 cause autosomal recessive, early‐onset Parkinson's disease (PD). The precise function and distribution of DJ‐1 in the central nervous system remain unclear. In this study, we performed a comprehensive analysis of DJ‐1 expression in human, monkey, and rat brains with antibodies that recognize distinct, evolutionarily conserved epitopes of DJ‐1. We found that DJ‐1 displays region‐specific neuronal and glial labeling in human and nonhuman primate brain, sharply contrasting with the primarily neuronal expression pattern observed throughout rat brain. Further immunohistochemical analysis of DJ‐1 expression in human and nonhuman primate brains showed that DJ‐1 protein is expressed in neurons within the substantia nigra pars compacta and striatum, two regions critically involved in PD pathogenesis. Moreover, immunoelectron microscopic analysis revealed a selective enrichment of DJ‐1 within primate striatal axons, presynaptic terminals, and dendritic spines with respect to the DJ‐1 expression in prefrontal cortex. Together, these findings indicate neuronal and synaptic expression of DJ‐1 in primate subcortical brain regions and suggest a physiological role for DJ‐1 in the survival and/or function of nigral‐striatal neurons. J. Comp. Neurol. 500:585–599, 2007. © 2006 Wiley‐Liss, Inc.
When controversial leaders with charisma are effective: the influence of terror on the need for vision and impact of mixed attitudinal messages
Authors: Gordijn Ernestine H. , Stapel Diederik A. 
Published: November 2006

AbstractWe investigated the idea that a charismatic leader with a controversial message is most likely to persuade people in times of terror, because in those times people have a high need for vision, and vision is what a charismatic leader provides. In addition, we argued that the leader's message should contain a pro‐attitudinal position as well, as this makes the counter‐attitudinal message more palatable. In line with our hypotheses, we found in Experiment 1 that thinking about terrorism increases people's need for vision. Experiment 2 revealed that only when people have a high need for vision they will be influenced by a controversial charismatic leader. Experiment 3 showed that existential threats also directly increase the influence of a controversial charismatic leader. Further, this was especially so when the charismatic leader was both attractive and communicated his message in a charismatic way. Finally, Experiment 4 revealed that after thinking about their own death or about terrorist attacks, people were most likely to be persuaded by a controversial charismatic leader whose counter‐attitudinal message also contained pro‐attitudinal statements. Together, this research suggests that in times of terror people's need for vision increases, which opens them up to a counter‐attitudinal message of a charismatic leader as long as this message also includes some pro‐attitudinal statements. Copyright © 2006 John Wiley & Sons, Ltd.
Usefulness of microchip electrophoresis for the analysis of mitochondrial DNA in forensic and ancient DNA studies
Authors: Alonso Antonio , Albarran Cristina , Martín Pablo , García Pilar , Capilla Javier , García Oscar , de la Rua Concepción , Izaguirre Neskuts , Pereira Filipe , Pereira Luisa , Amorim António , Sancho Manuel 
Published: November 2006

AbstractWe evaluate the usefulness of a commercially available microchip CE (MCE) device in different genetic identification studies performed with mitochondrial DNA (mtDNA) targets, including the haplotype analysis of HVR1 and HVR2 and the study of interspecies diversity of cytochrome b (Cyt b) and 16S ribosomal RNA (16S rRNA) mitochondrial genes in forensic and ancient DNA samples. The MCE commercial system tested in this study proved to be a fast and sensitive detection method of length heteroplasmy in cytosine stretches produced by 16 189T>C transitions in HVR1 and by 309.1 and 309.2 C‐insertions in HVR2. Moreover, the quantitative analysis of PCR amplicons performed by LIF allowed normalizing the amplicon input in the sequencing reactions, improving the overall quality of sequence data. These quantitative data in combination with the quantification of genomic mtDNA by real‐time PCR has been successfully used to evaluate the PCR efficiency and detection limit of full sequencing methods of different mtDNA targets. The quantification of amplicons also provided a method for the rapid evaluation of PCR efficiency of multiplex‐PCR versus singleplex‐PCR to amplify short HV1 amplicons (around 100 bp) from severely degraded ancient DNA samples. The combination of human‐specific (Cyt b) and universal (16S rRNA) mtDNA primer sets in a single PCR reaction followed by MCE detection offers a very rapid and simple screening test to differentiate between human and nonhuman hair forensic samples. This method was also very efficient with degraded DNA templates from forensic hair and bone samples, because of its applicability to detect small amplicon sizes. Future possibilities of MCE in forensic DNA typing, including nuclear STRs and SNP profiling are suggested.
Informative‐Transmission Disequilibrium Test (i‐TDT): combined linkage and association mapping that includes unaffected offspring as well as affected offspring
Authors: Guo Chao‐Yu , Lunetta Kathryn L. , DeStefano Anita L. , Ordovas Jose M. , Adrienne Cupples L. 
Published: November 2006

AbstractTo date, there is no test valid for the composite null hypothesis of no linkage or no association that utilizes transmission information from heterozygous parents to their unaffected offspring as well as the affected offspring from ascertained nuclear families. Since the unaffected siblings also provide information about linkage and association, we introduce a new strategy called the informative‐transmission disequilibrium test (i‐TDT), which uses transmission information from heterozygous parents to all of the affected and unaffected offspring in ascertained nuclear families and provides a valid chi‐square test for both linkage and association. The i‐TDT can be used in various study designs and can accommodate all types of independent nuclear families with at least one affected offspring. We show that the transmission/disequilibrium test (TDT) (Spielman et al. [1993] Am. J. Hum. Genet. 52:506–516) is a special case of the i‐TDT, if the study sample contains only case‐parent trios. If the sample contains only affected and unaffected offspring without parental genotypes, the i‐TDT is equivalent to the sibship disequilibrium test (SDT) (Horvath and Laird [1998] Am. J. Hum. Genet. 63:1886–1897. In addition, the test statistic of i‐TDT is simple, explicit and can be implemented easily without intensive computing. Through computer simulations, we demonstrate that power of the i‐TDT can be higher in many circumstances compared to a method that uses affected offspring only. Applying the i‐TDT to the Framingham Heart Study data, we found that the apolipoprotein E (APOE) gene is significantly linked and associated with cross‐sectional measures and longitudinal changes in total cholesterol. Genet. Epidemiol. © 2006 Wiley‐Liss, Inc.
Interpretation of simultaneous linkage and family‐based association tests in genome screens
Authors: Chung Ren‐Hua , Hauser Elizabeth R. , Martin Eden R. 
Published: November 2006

AbstractLinkage and association analyses have played important roles in identifying susceptibility genes for complex diseases. Linkage tests and family‐based tests of association are often applied in the same data to help fine‐map disease loci or validate results. This paradigm increases efficiency by making maximal use of family data sets. However, it is not intuitively clear under what conditions association and linkage tests performed in the same data set may be correlated. Understanding this relationship is important for interpreting the combined results of both tests. We used computer simulations and theoretical statements to estimate the correlation between linkage statistics (affected sib pair maximum LOD scores) and family‐based association statistics (pedigree disequilibrium test (PDT) and association in the pressure of linkage (APL)) under various hypotheses. Different types of pedigrees were studied: nuclear families with affected sib pairs, extended pedigrees and incomplete pedigrees. Both simulation and theoretical results showed that when there is no linkage or no association, the linkage and association tests are not correlated. When there is linkage and association in the data, the two tests have a positive correlation. We concluded that when linkage and association tests are applied in the same data, the type I error rate of neither test will be affected and that power can be increased by applying tests conditionally. Genet. Epidemiol. © 2006 Wiley‐Liss, Inc.
Down‐regulation of S100A2 in lymph node metastases of head and neck cancer
Authors: Zhang Xin , Hunt Jennifer L. , Shin Dong M. , Chen Zhuo (Georgia) 
Published: November 2006

AbstractBackground.Our cDNA microarray analysis of squamous cell carcinoma of the head and neck (SCCHN) previously identified that S100A2 was down‐regulated in highly metastatic 686LN‐M3s cell lines established through in vivo selection using a metastatic xenograft mouse model. S100A2, a putative tumor suppressor, has been found to be down‐regulated in several types of primary tumor as compared with the normal tissue. Only a few reports have explored its expression status and function in metastasis.Methods.To further confirm down‐regulation of S100A2 in human metastasis, we examined S100A2 expression using immunohistochemical analysis of paraffin‐embedded SCCHN tissues. The samples included primary SCCHN tumors (Tu‐1) and involved lymph nodes (Met‐1) from the same patients, and primary tumors in node‐negative patients (Tu‐2).Results.Most of these tumors expressed S100A2 but lymph node metastases showed a pattern of reduced staining for S100A2 compared with primary tumors. A similar expression pattern of S100A2 was also observed in several SCCHN cell lines by reverse transcription‐polymerase chain reaction (RT‐PCR) and immunoblotting. Particularly, S100A2 expression was lower in 686LN than Tu686 and hardly detectable in the metastatic derivatives 686LN‐M3s. Further study of S100A2 promoter showed higher methylation intensity in these metastatic derivatives than in Tu686 and 686LN.Conclusions.S100A2 was down‐regulated in lymph node metastasis of SCCHN, suggesting that instead of being a putative tumor suppressor, S100A2 may play a role in the metastasis of SCCHN. © 2006 Wiley Periodicals, Inc. Head Neck, 2007