bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of the length of the substituents on the phase structure and transition behavior of a series of laterally attached side‐chain liquid‐crystalline polynorbornenes
Authors: Kim Gue‐Hyun , Jin Shi , Pugh Coleen , Cheng Stephen Z. D. 
Published: August 2002

AbstractA series of polynorbornenes (PNBEs) with 1,4‐bis[(3′‐fluoro‐4′‐n‐alkoxyphenyl)ethynyl]benzene mesogens (n = 1–12, where n is the number of methylene units in the substituents of the mesogens) laterally attached to polymer backbones through a one‐carbon spacer were previously synthesized by the ring‐opening metathesis polymerization of the corresponding norbornene‐based monomers. Differential scanning calorimetric results showed that the first‐order transition temperatures exhibit an odd–even alternation, especially when PNBEs have lower values of n. PNBE (n = 8), similar to the previously studied PNBEs (n = 9–12), shows a smectic C (SC) phase at room temperature (Kim, Pugh, and Cheng, Macromolecules, 33, 8983, 2000.) According to one‐ and two‐dimensional wide‐angle X‐ray scattering experiments, PNBEs (n = 2–7) exhibit a nematic (N) phase with SC fluctuations, whereas for PNBE (n = 1), only an N phase is observed. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 3029–3037, 2001
Thermoresponsive conductivity of poly(N‐isopropylacrylamide)/potassium chloride gel electrolytes
Authors: Chen Jinhua , Maekawa Yasunari , Yoshida Masaru , Tsubokawa Norio 
Published: August 2002

AbstractA series of thermoresponsive polymer gel electrolytes (PGEs) based on poly(N‐isopropylacrylamide) in aqueous potassium chloride was synthesized by radiation‐induced polymerization and gelation using γ rays from a 60Co source. The electric conductivity and swelling properties of the PGE were determined as a function of temperature. It was found that the electric conductivity of the PGE depended strongly on the swelling ratio; most notably, it changed drastically near the volume phase‐transition temperature of the PGE. The temperature/conductivity profile of the PGE exhibits a maximum peak at a certain temperature that is defined as the maximum conductivity temperature (Tmax). The Tmax of all of the PGEs prepared by low‐dose irradiation agreed with the temperature, near the end of the volume phase transition, where the PGE was completely shrunken. Consequently, the conductivity of gels should provide a good method with which the totally shrunken temperature of the thermoresponsive gels can be monitored with good temperature precision. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 40: 134–141, 2002
Dynamic mechanical analyses of Nafion®/organically modified silicate nanocomposites
Authors: Young S. K. , Mauritz K. A. 
Published: August 2002

AbstractNafion®/organically modified silicate (ORMOSIL) hybrids were generated via polymer in situ sol–gel copolymerizations of tetraethylorthosilicate (TEOS) with difunctional and trifunctional organoalkoxysilane monomers, and the dynamic mechanical relaxations and thermomechanical stability of the resultant composites were investigated. All ORMOSIL fillers restrict main‐chain and side‐chain mobility. The results suggest that sulfonic acid side chains become entrapped in silicate or ORMOSIL structures that evolve during the in situ sol–gel process. Some but not all of the ORMOSIL combinations display trends in the α or β relaxation temperature with respect to the TEOS comonomer ratio. All of the hybrids have greater high‐temperature thermomechanical stability than the unfilled acid form. There are definite composition trends in the vertical displacement of the storage‐modulus–temperature curves. For some of the semiorganic comonomers, there is a monotonic increase in storage modulus with decreasing comonomer content in the high‐temperature regime, which is understood in terms of a progressive immobilization of the long side chains by progressively more rigid ORMOSIL nanostructures. For other semiorganic comonomers, the high‐temperature plateau shifts upward to a maximum and then shifts downward with decreasing comonomer fraction. In addition to the chemical nature of the imparted nanophases, these molecular motions are expected to influence the transport properties of these novel heterogeneous membranes. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1282–1295, 2001
Enthalpy distributions and densities of states in linear polymers
Authors: Poland Douglas 
Published: August 2002

AbstractUsing polypropylene as an example, we applied a method we have recently developed to calculate the probability distribution of enthalpy from the temperature dependence of the heat capacity. The method involves the use of local temperature expansions of the heat capacity to calculate a set of moments of the enthalpy distribution. Using the maximum‐entropy method, one can then construct the enthalpy distribution for the system. The method is completely model free. The enthalpy distribution so obtained is the analogue of the Maxwell–Boltzmann distribution of kinetic energies for a gas, and like that function, tells one the distribution of enthalpies that an average unit in the polymer chain can have, a quantity that is crucial to understanding the chemical and physical properties of a polymer. Given the enthalpy distribution, one can then calculate the Gibbs free energy and the density of states that correspond to a particular value of enthalpy, thus giving one an expanded thermodynamics of the system in addition to the usual average quantities. We illustrate the fact that the Gibbs free‐energy distribution for this system scales as a simple function of temperature and that the density‐of ‐states function yields a simple empirical partition function for the system giving both the average thermodynamics and the distribution functions. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1513–1518, 2001
Help‐seeking behaviour for cancer symptoms: perceptions of patients and general practitioners
Authors: De Nooijer Jascha , Lechner Lilian , De Vries Hein 
Published: August 2002

AbstractThe aim of this study is to increase our understanding of the relationship between knowledge and interpretation of symptoms, fear and trust on the one hand, and the decision to consult a general practitioner (GP) for cancer symptoms on the other. Qualitative interviews were used to evaluate the various factors. Twenty‐three patients and ten GPs were interviewed. A number of factors were found to play different roles for different patients groups, i.e. patients that consult their doctor prematurely, at the right time, or those that delay. A lot of the findings can be tested using various concepts of socio‐psychological theory. Further research should provide an improved understanding of the way these models can be applied to help‐seeking behaviour. In terms of implications for health education, we conclude that each patient group has different needs and requires different information. Copyright © 2001 John Wiley & Sons, Ltd.
The oriented lakes of Tuktoyaktuk Peninsula, Western Arctic Coast, Canada: a GIS‐based analysis
Authors: Côté M. M. , Burn C. R. 
Published: August 2002

AbstractThe orientation, size and shape of 578 lakes on Tuktoyaktuk Peninsula were obtained from 1 : 250 000 Canadian National Topographic Survey map sheets, using ArcView geographic information system. These lakes are outside the glacial limits in a tundra plain with <15m relief. The lakes range from 20 to 1900 ha, and have mean orientation N07 °E, with standard error 1.6°. The maps show 145 former lake basins, with lakes inset in 130 of these. The mean orientations of the basins and inset lakes are not statistically different from each other or the general population. Several theories have been proposed for the origin of the oriented lakes, and one theory attributes the orientation to cross winds establishing currents that preferentially erode the ends of the lakes. Data from Tuktoyaktuk and Nicholson for 1970–95 indicate a consistent wind regime within the region, with prevailing winds from the east and west. Using data from Nicholson, a geometric model generates resultant lake orientations of N if all winds are considered, and N08 °E if winds above 30km h−1 are used. The coincidence of the modelled orientation and lake statistics supports the efficacy of cross wind‐induced effects in orienting the lakes. The similar orientation of existing lakes and former basins suggests that these processes have been effective for at least several centuries. Copyright © 2002 John Wiley & Sons, Ltd.
Bronchoscopically administered recombinant human DNase for lobar atelectasis in cystic fibrosis*
Authors: Slattery Dubhfeasa M. , Waltz David A. , Denham B. , O'Mahony M. , Greally P. 
Published: August 2002

AbstractLobar atelectasis is a common complication of cystic fibrosis. The majority of cases respond to intravenous antibiotics and chest physiotherapy. In a subgroup of patients, atelectasis is resistant to medical therapy, and its persistence in the pediatric population is associated with a poor prognosis.Bronchoscopic instillation of human recombinant DNase expanded atelectatic lobes in three children resistant to at least 2 weeks of medical therapy. This method of administration of DNase has been successful in resistant cases of lobar atelectasis in patients with chronic obstructive pulmonary disease, quadriplegia, and status asthmaticus. Purulent cystic fibrosis sputum has a very high DNA content, and DNA has been shown to become more pourable in vitro when treated with rhDNase.Bronchoscopic instillation of rhDNase should be considered in cases of persistent lobar atelectasis unresponsive to medical therapy. Pediatr Pulmonol. 2001; 31:383–388. © 2001 Wiley‐Liss, Inc.
Epidemiology of bronchial asthma and chronic rhinitis in schoolchildren of different ethnic origins from two neighboring towns in Israel
Authors: Kivity Shaye , Sade Kobi , Abu‐Arisha Fuad , Lerman Yehuda , Kivity Shmuel 
Published: August 2002

AbstractAllergic diseases have increased significantly in developed countries for reasons yet to be determined. We studied the epidemiology of bronchial asthma (B.A.) and chronic rhinitis (Ch.R.) among Israeli school children from two neighboring towns, one Jewish (Zichron Yaakov, school population = 585) and the other Arab (Paradis, school population = 658). The children (age range 8–17 years, 567 males, 676 females) shared the same climate and had similar demographic characteristics. They received similar medical care and had the same rates of hospitalization and emergency room visits.The Jewish children had a higher prevalence of B.A. (13.7% vs. 9.4%), Ch.R. (19.7% vs. 9.7%), and stuffy nose (31% vs. 14%) than their Arab counterparts. In addition to ethnicity, parental smoking habits were the major differentiating factor between the two groups: 20% of the mothers and 29% of the fathers from Zichron Yaakov and 2% of the mothers and 60% of the fathers from Paradis were smokers. Smoking fathers increased the rate of B.A. in both towns as well as emergency room visits, but not the rate of Ch.R. or stuffy nose. A familial history of B.A. was the main determinant for having childhood asthma or chronic rhinitis.We conclude that in addition to family history and ethnicity, smoking among mothers was the major contributing factor for the higher prevalence of atopic diseases among Jewish schoolchildren compared to their Arab counterparts. Pediatr Pulmonol. 2001; 32:217–221. © 2001 Wiley‐Liss, Inc.
Vitamin D receptor gene polymorphism and prostate cancer risk
Authors: Gsur Andrea , Madersbacher Stephan , Haidinger Gerald , Schatzl Georg , Marberger Michael , Vutuc Christian , Micksche Michael 
Published: August 2002

AbstractBACKGROUND1,25‐dihydroxyvitamin D, the active form of vitamin D, exerts antiproliferative effect on prostatic cells, mediated through the vitamin D receptor. In a case‐control study, we examined whether the vitamin D receptor (VDR) gene polymorphism in exon 9 could affect prostate cancer susceptibility.METHODSOne hundred ninety newly diagnosed prostate cancer patients and 190 age‐matched men with benign prostatic hyperplasia (BPH), in whom the presence of prostate cancer was excluded clinically or histologically, were recruited for this study. The VDR TaqI polymorphism was investigated by polymerase chain reaction (PCR) following restriction fragment length polymorphism using DNA from lymphocytes. Depending on the presence or absence of the TaqI restriction site at the third position of codon 352, patients were classified as TT, Tt, or tt.RESULTSThe frequency of the tt genotype was not significantly different between prostate cancer patients (18%) and controls (12%; P = 0.07). The odds ratio (OR), calculated relative to individuals with the TT genotype was 1.76 (95% confidence limit (CL) = 0.90–3.45). After stratification for Gleason score and prostate specific antigen levels in a case–case comparison (n = 190), no significant associations with the VDR genotypes were detectable either.CONCLUSIONSIn this case‐control study of Austrian Caucasians, no statistically significant association of the VDR TaqI polymorphism and prostate cancer risk was found. Prostate 51:30–34, 2002. © 2002 Wiley‐Liss, Inc.
Molecular staging of surgical margins after radical prostatectomy by detection of telomerase activity
Authors: Straub Bernd , Müller Markus , Krause Hans , Goessl Carsten , Schrader Mark , Heicappell Rüdiger , Miller Kurt 
Published: August 2002

AbstractBackgroundThe further course of prostate cancer (PC) after radical prostatectomy (RPX) is decisively influenced by the local tumor stage. Although it is thus far possible to assess the risk of local recurrence from the pathohistology, precise predictions cannot be made. A more precise evaluation would be desirable, mainly for early planning of adjuvant therapy. Other authors have shown that telomerase activity may be a marker for malignant potential. We assessed the detection of telomerase activity using the telomeric repeat amplification protocol (TRAP) in surgical margins compared to conventional histopathological examination.MethodsNinety‐two patients with local PC who underwent RPX were examined. After RPX biopsies were obtained from four defined areas of the prostatic fossa and processed by TRAP assay for telomerase activity using a standard protocol.ResultsIn 5 of 48 patients (10.4%) with organ‐confined prostate carcinoma (pT2) telomerase activity could be detected. Seven of 47 patients (14.9%) with locally advanced PC (> pT2) had at least one positive specimen.ConclusionsThe results obtained in our study indicate that detection of telomerase activity by TRAP assay may be a suitable parameter for molecular staging of surgical margins, because of the high tumor‐specificity. Further follow‐up must clarify whether patients with positive molecular detection have an increased risk of local recurrence. Prostate 49:140–144, 2001. © 2001 Wiley‐Liss, Inc.
In silico two‐hybrid system for the selection of physically interacting protein pairs
Authors: Pazos Florencio , Valencia Alfonso 
Published: August 2002

AbstractDeciphering the interaction links between proteins has become one of the main tasks of experimental and bioinformatic methodologies. Reconstruction of complex networks of interactions in simple cellular systems by integrating predicted interaction networks with available experimental data is becoming one of the most demanding needs in the postgenomic era. On the basis of the study of correlated mutations in multiple sequence alignments, we propose a new method (in silico two‐hybrid, i2h) that directly addresses the detection of physically interacting protein pairs and identifies the most likely sequence regions involved in the interactions. We have applied the system to several test sets, showing that it can discriminate between true and false interactions in a significant number of cases. We have also analyzed a large collection of E. coli protein pairs as a first step toward the virtual reconstruction of its complete interaction network. Proteins 2002;47:219–227. © 2002 Wiley‐Liss, Inc.
QSAR: Hydropathic analysis of inhibitors of the p53–mdm2 interaction
Authors: Galatin Peter S. , Abraham Donald J. 
Published: August 2002

AbstractTo date, a number of p53‐derived peptides have been evaluated in vitro for their ability to inhibit the carcinogenic p53–mdm2 interaction. Design of second‐generation nonpeptidic compounds requires the reduction of large peptide structures down to small molecules maintaining the proper spatial arrangement of key functional groups. Molecular modeling software exists that can predict and rank intermolecular interactions from the p53–mdm2 complex crystal structure. Such analyses can yield a pharmacophore model suitable as a search query for a 3D chemical database to generate new lead compounds. As preliminary validation of this methodology, the Hydropathic INTeractions (HINT) program has been used to generate noncovalent interaction measurements between reported peptide inhibitors and mdm2. Quantitative structure–activity relationships were developed expressing peptide activity as a linear combination of hydropathic descriptors. In general, HINT measurements accurately modeled the effects of even single‐atom alterations of the p53–peptide structure on activity, accounting for 70–90% of variation in experimental inhibition constants. These results surpassed those of a recently described molecular dynamics‐based approach and required significantly less computation time. In conclusion, the HINT program can be integrated into the drug design cycle for next‐generation p53–mdm2 complex inhibitors with confidence in its ability to simulate this noteworthy protein–protein interaction. Proteins 2001;45:169–175. © 2001 Wiley‐Liss, Inc.
Theoretical study of the conformation of the lipoamide arm in a mutant H protein
Authors: Roche Olivier , Field Martin J. 
Published: August 2002

AbstractThe lipoamide arm of the H protein plays a pivotal role in the catalytic cycle of the glycine decarboxylase complex (GDC) by being successively methylamine loaded (Hmet), reduced (Hred), and oxidized (Hox). In a previous study, we calculated free‐energy surfaces as a function of the lipoamide arm position of the three forms of the wild‐type protein and found close agreement with the available experimental data. Our simulations, together with crystallographic and NMR data, showed that the methylamine‐loaded arm is locked in a cavity by interaction with Ser12, Glu14, and Asp67. In this work, we investigate the behavior of the methylamine‐loaded form of a mutant H protein (HEA) where Glu14 has been replaced by Ala. We find that the arm can still be held in the cavity but that the energy barrier to release of the arm is halved from ∼40 kcal mol−1 for Hmet to ∼12 kcal mol−1 for HEA. To compensate for the loss of Glu14, the methylamine group shifts toward Ser66 in the mutant form. These results provide a structural basis for the equilibrium between the loaded and the unloaded forms of the arm observed by Gueguen et al. (Gueguen et al., J Biol Chem 1999;274:26344–26352) in HEA. Proteins 2001;45:237–240. © 2001 Wiley‐Liss, Inc.
Thermal decomposition and isomerization of cis‐permethrin and β‐cypermethrin in the solid phase
Authors: González Audino Paola , Licastro Susana A , Zerba Eduardo 
Published: August 2002

AbstractThe stability to heat of cis‐permethrin and β‐cypermethrin in the solid phase was studied and the decomposition products identified. Samples heated at 210 °C in an oven in the dark showed that, in the absence of potassium chlorate (the salt present in smoke‐generating formulations of these pyrethroids), cis‐permethrin was not isomerized, although in the presence of that salt, decomposition was greater and thermal isomerization occured. Other salts of the type KXO3 or NaXO3, with X being halogen or nitrogen, also led to a considerable thermal isomerization. Heating the insecticides in solution in the presence of potassium chlorate did not produce isomerization in any of the solvents assayed. Salt‐catalysed thermal cis–trans isomerization was also found for other pyrethroids derived from permethrinic or deltamethrinic acid but not for those derived from chrysanthemic acid. The main thermal degradation processes of cis‐permethrin and β‐cypermethrin decomposition when potassium chlorate was present were cyclopropane isomerization, ester cleavage and subsequent oxidation of the resulting products. Permethrinic acid, 3‐phenoxybenzyl chloride, alcohol, aldehyde and acid were identified in both cases, as well as 3‐phenoxybenzyl cyanide from β‐cypermethrin. A similar decomposition pattern occurred after combustion of pyrethroid fumigant formulations.© 2001 Society of Chemical Industry
Linkage of genes for sodium channel and cytochrome P450 (CYP6B10) in Heliothis virescens
Authors: Park Sujin , Brown Thomas M 
Published: August 2002

AbstractGenetic linkage of hscp (heliothis sodium channel protein) and CYP6B10 was discovered in Heliothis virescens. The hscp gene encodes the sodium channel target of pyrethroid insecticides and cytochrome P450 genes encode important enzymes involved in detoxication of various pesticides. Previously, two mechanisms, nerve insensitivity due to sodium channel and synergism by propynyl aryl ethers, were observed in pyrethroid‐resistant H virescens and were not separated by repeated back‐crossing. We hypothesized genetic linkage of target site insensitivity and monooxygenase‐mediated detoxication. Single nucleotide polymorphisms were discovered in IIS6 of hscp; Hpy of hscp and CYP6B10. Segregation of these and other markers was tested in backcrosses. We observed co‐segregation of hscp to CYP6B10, but both genes assorted independently of y, ye and sex. Genes y and ye assorted independently of each other. This was the first observation of linkage between genes controlling detoxication and sodium ion channel insensitivity in a species known to express high levels of pyrethroid resistance. Linkage was not likely because this species has 31 chromosomes; therefore, we will investigate the possibility of a resistance cassette. We expect similar linkage in other noctuid pests.© 2001 Society of Chemical Industry
Semiochemical strategies for sea louse control: host location cues
Authors: Ingvarsdóttir Anna , Birkett Michael A , Duce Ian , Genna Richard L , Mordue William , Pickett John A , Wadhams Lester J , Mordue (Luntz) A Jennifer 
Published: August 2002

AbstractThe development of behavioural bioassays and electrophysiological recording techniques has enabled the role of semiochemicals to be investigated for the first time in Lepeophtheirus salmonis (Krøyer). Adult male sea lice L salmonis were activated by, and attracted to, salmon‐conditioned water (SCW) and SCW extract. Non‐host fish odours, turbot‐conditioned water (TCW) and turbot‐conditioned water extract (TCW extract), elicited activation but no attraction in the lice. Solid‐phase extraction techniques were developed to extract low molecular weight components of fish odours, and biological activity was shown to be confined to these. Electrophysiological activity from aesthetascs in the first antennae was found and neural responses to odours were recorded from the antennal nerves. Preliminary experiments on individual chemicals (isophorone, 1‐octen‐3‐ol) linked to salmon revealed behavioural activation and electrophysiological responses in adult male L salmonis. Isophorone was shown to be significantly attractive to sea lice when placed in a slow‐release system in a perfused tank of seawater in a choice situation. Proof of concept has been established for successfully extracting odour cues from seawater, analysing their biological activity and applying these to slow‐release technologies for field trapping of lice. Future work involving linked GC–MS techniques using behaviour, electrophysiological responses, and organolepsis will establish further host location cues specific to Atlantic salmon.© 2002 Society of Chemical Industry