bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dielectric and conduction properties of pure polyimide films
Authors: Muruganand S , Narayandass Sa K , Mangalaraj D , Vijayan T M 
Published: August 2002

AbstractCapacitors with an Al–polyimide–Al sandwich film structure have been fabricated: the top and the bottom aluminium electrodes were deposited by vacuum evaporation and the polyimide film was deposited by an isothermal immersion method. An X‐ray diffractogram of the film indicates the amorphous nature of the polyimide film. Dielectric and ac conduction properties of polyimide capacitors in the frequency range 10 kHz to 10 MHz at various temperatures (303–423 K) are reported; the dc conduction at different voltages and at various temperatures (303–423 K) is given. The capacitance of the film decreases with increasing frequency but increases with increasing temperature. The ac conduction studies suggest that electron hopping is responsible for conduction while the dc conduction studies reveal that Poole–Frenkel conduction is predominant at high fields. The activation and zero field activation energies are also calculated.© 2001 Society of Chemical Industry
Contemporary practices in school psychology: A national survey of roles and referral problems
Authors: Bramlett Ronald K. , Murphy John J. , Johnson Jenna , Wallingsford Leah , Hall John D. 
Published: August 2002

AbstractEight hundred school psychologists who were members of the National Association of School Psychologists were mailed a survey designed to assess their roles, types of referrals, consultation practices, and crisis team involvement. Three hundred seventy (49%) completed surveys were analyzed. Assessment was the most common role followed distantly by consultation. Academic problems were the most frequent type of referral with reading being the most common concern. Of the behavioral referrals, externalizing problems were more frequent than internalizing concerns. Behavioral consultation was the most common model used but less than half of respondents follow all of the stages. Only forty percent use an evaluative component in consultation. A majority of the informants had some involvement with their schools' crisis team. Implications of these findings for training, professional development, and future roles are discussed. © 2002 Wiley Periodicals, Inc.
Interactional models of learning disabilities: Evidence from students entering foster care
Authors: Evans Larry D. 
Published: August 2002

AbstractChildren are increasingly entering foster care due to primary or secondary neglect in the home environment. They provide a unique opportunity to examine the relationship between learning and extrascholastic environments. Achievement and intelligence scores were obtained for 3483 school‐age children during the first 30 to 60 days of foster care placement. Results showed average to low‐average mean achievement and IQ, with primary academic deficits in basic skill areas. One or more severe (≥1.75 SD) regressed discrepancies was found for 25.4% of children, and 76.6% showed one or more areas of academic underachievement (≤25th percentile). Results are interpreted as supporting interactional models of learning disability etiology that recognize environmental, neurologic, instructional, and behavioral variables. © 2001 John Wiley & Sons, Inc.
Preparation of functionalized montmorillonites and their application in supported zirconocene catalysts for ethylene polymerization
Authors: Liu Chengbin , Tang Tao , Zhao Zhongfu , Huang Baotong 
Published: August 2002

AbstractEthylene polymerization was carried out with zirconocene catalysts supported on montmorillonite (or functionalized montmorillonite). The functionalized montmorillonite was from simple ion exchange of [CH3O2CCH2NH3]+(MeGlyH+) ions with interlamellar cations of layered montmorillonites. The functionalized montmorillonites [high‐purity montmorillonite (MMT)‐MeGlyH+] had larger interlayer spacing (12.69 Å) than montmorillonites without treatment (9.65 Å). The zirconocene catalyst system [Cp2ZrCl2/methylaluminoxane (MAO)/MMT‐MeGlyH+] had much higher Zr loading and higher activities than those of other zirconocene catalyst systems (Cp2ZrCl2/MMT, Cp2ZrCl2/MMT‐MeGlyH+, Cp2ZrCl2/MAO/MMT, [Cp2ZrCl]+[BF4]/MMT, [Cp2ZrCl]+[BF4]−/MMT‐MeGlyH+, [Cp2ZrCl]+[BF4]−/MAO/MMT‐MeGlyH+, and [Cp2ZrCl]+[BF4]−/MAO/MMT). The polyethylenes with good bulk density were obtained from the catalyst systems, particularly (Cp2ZrCl2/MAO/MMT‐MeGlyH+). MeGlyH+and MAO seemed to play important roles for preparation of the supported zirconocenes and polymerization of ethylene. The difference in Zr loading and catalytic activity among the supported zirconocene catalysts is discussed. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1892–1898, 2002
Preparation of oriented β‐form poly(L‐lactic acid) by solid‐state extrusion
Authors: Sawai Daisuke , Takahashi Kazuyo , Imamura Toshiyuki , Nakamura Koh , Kanamoto Tetsuo , Hyon Suong‐Hyu 
Published: August 2002

AbstractMelt‐crystallized, low molecular weight poly(L‐lactic acid) (PLLA) consisting of α crystals was uniaxially drawn by solid‐state extrusion at an extrusion temperature (Text) of 130–170 °C. A series of extrusion‐drawn samples were prepared at an optimum Text value of 170 °C, slightly below the melting temperature (Tm) of α crystals (∼180 °C). The drawn products were characterized by deformation flow profiles, differential scanning calorimetry (DSC) melting thermograms, wide‐angle X‐ray scattering (WAXD), and small‐angle X‐ray scattering as a function of the extrusion draw ratio (EDR). The deformation mode in the solid‐state extrusion of semicrystalline PLLA was more variable and complex than that in the extensional deformation expected in tensile drawing, which generally gave a mixture of α and β crystals. The deformation profile was extensional at a low EDR and transformed to a parabolic shear pattern at a higher EDR. At a given EDR, the central portion of an extrudate showed extensional deformation and the shear component became progressively more significant, moving from the center to the surface region. The WAXD intensities of the (0010)α and (003)β reflections on the meridian as well as the DSC melting thermograms showed that the crystal transformation from the initial α form to the oriented β form proceeded rapidly with increasing EDR at an EDR greater than 4. Furthermore, WAXD showed that the crystal transformation proceeded slightly more rapidly at the sheath region than at the core region. This fact, combined with the deformation profiles (shear at the sheath and extensional at the core), indicated that the crystal transformation was promoted by shear deformation under a high pressure rather than by extensional deformation. Thus, a highly oriented rod consisting of only β crystals was obtained by solid‐state extrusion of melt‐crystallized, low molecular weight PLLA slightly below Tm. The structure and properties of the α‐ and β‐form crystals were also studied. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 40: 95–104, 2002
Contact of elastic solids with rough surfaces
Authors: Kim Ho‐Cheol , Russell Thomas P. 
Published: August 2002

AbstractThe effect of surface roughness on the adhesion of elastic solids was examined with artificially roughened surfaces and crosslinked poly(dimethylsiloxane). The amplitudes (σ) and lateral correlation lengths (ξ) of the surface roughness were determined with the height–height correlation function calculated from atomic force microscopy images. The work of adhesion (W) did not change significantly for surfaces where σ ≤ 6 nm. However, with increasing σ and (ξ2/σ)1/3, W increased. Maximal adhesion was found for surfaces that produced the greatest indentation. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1848–1854, 2001
Aging and cold crystallization of melt‐extruded poly(trimethylene terephthalate) films
Authors: Cho Jae Whan , Woo Kyung Sik 
Published: August 2002

AbstractWe analyzed the thermal crystallization, glass‐transition behavior, and mechanical properties of melt‐extruded poly(trimethylene terephthalate) (PTT) films to investigate their physical aging and annealing effects. The physical aging and annealing of PTT films had an influence on the glass‐transition temperature, recrystallization behavior, and mechanical properties. When samples were aged at an ambient temperature, the crystallization temperature decreased largely within 5 h, the heat of crystallization increased, and the breaking stress and breaking elongation increased. The glass‐transition temperature of annealed samples, which was obtained from differential scanning calorimetry and dynamic mechanical measurements, increased with increasing annealing temperature below 80 °C but decreased above that temperature. In addition, the glass‐transition temperature and modulus of annealed samples were largely affected by the annealing time; in particular, they increased sharply within 1 h on annealing at 50 °C. Consequently, the change in the glass‐transition temperature on annealing was ascribed to the fact that the molecular constraint due to recrystallization and the mobility of rigid amorphous PTT chains competed with each other, being dependent on the annealing temperature. The mechanical properties of aged samples were closely related to their cold‐crystallization behavior. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1920–1927, 2001
Dynamic mechanical relaxation behavior of block copolymers at high temperatures
Authors: Mohammady S. Z. , Mansour A. A. , Stoll B. 
Published: August 2002

AbstractWe carried out dynamic mechanical measurements to investigate three different examples of block copolymers: styrene–isoprene diblock copolymers and styrene–butadiene–styrene and styrene–(styrene butadiene)–styrene triblock copolymers. Isochronal and isothermal measurements of the real and imaginary parts of the complex shear modulus were performed over wide ranges of temperature and frequency. The measurements showed the presence of an additional relaxation process appearing at temperatures higher than those of the glass relaxation of the polystyrene phase, which has been misinterpreted by some authors as an order–disorder transition. The frequency dependence revealed that this process was a relaxation process and did not belong to a first‐order transition. Moreover, the influence of crosslinking via dicumylperoxide was measured, and we constructed complete master curves to confirm the presence of two relaxation processes. The high‐temperature relaxation process was strongly suppressed by crosslinking. Therefore, it was possible to detect the glass relaxation process of the polystyrene phase in a precise manner. The results were compared with those of homopolymers. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2198–2206, 2001
Predicting major depression in brain tumor patients
Authors: Wellisch David K. , Kaleita Thomas A. , Freeman Donald , Cloughesy Timothy , Goldman Jeffrey 
Published: August 2002

AbstractVery few studies have been performed utilizing DSM criteria to diagnose major depressive disorder (MDD) in adult brain tumor patients. This study aimed to diagnose MDD in this population using DSM‐IV criteria.Eighty‐nine adult brain tumor patients were examined in an ambulatory neuro‐oncology clinic setting using a structured psychiatric interview which followed current DSM‐IV diagnostic criteria for MDD. This sample was interviewed and evaluated on a one‐time basis. The patients were referred for evaluation on a consecutive basis. Multiple regression was used to model critical independent variables to predict MDD.Twenty‐eight percent of the sample (N=89) were found to have major depressive disorder using DSM‐IV criteria. Key predictors of MDD included frontal region of tumor location (p=0.001), combined sadness and lack of motivation symptoms (p=0.0001), and family psychiatric history (p=0.006). The multiple regression models account for 37% of variance in predicting MDD (R2=0.37).A substantially higher incidence of MDD was found in this sample of adult brain tumor patients compared with other adult, ambulatory cancer patients previously evaluated with DSM criteria. The incidence of MDD was about triple that found in other published studies using DSM criteria. Copyright © 2002 John Wiley & Sons, Ltd.
Five years later: a cross‐sectional comparison of breast cancer survivors with healthy women
Authors: Tomich Patriciav L. , Helgeson Vicki S. 
Published: August 2002

AbstractAlthough a number of studies have focused on initial adjustment to cancer, less is known about long‐term survival issues. The present study compared breast cancer survivors with age‐matched healthy controls (N=328) in terms of more subtle indicators of psychological well‐being as well as their general quality of life 5 yrs post‐diagnosis. Results indicated survivors generally perceive the world as less controllable and more random compared to healthy women. However, survivors perceive the same control over their daily lives as healthy women. Beliefs about personal control are most strongly associated with quality of life in both groups of women. Survivors also indicated that they derived some benefits from their experience with cancer, but these benefits had only a modest impact on quality of life. However, the belief that the experience had lasting harmful effects was associated with poor quality of life for survivors. In both groups, a continued search for meaning in life had a negative impact on quality of life. The strongest and most consistent correlate of quality of life for both survivors and healthy women was having a sense of purpose in life. Copyright © 2002 John Wiley & Sons, Ltd.
Salbutamol dry powder inhaler: Efficacy, tolerability, and acceptability study*
Authors: O'Callaghan Chris , Everard Mark L. , Bush Andrew , Hiller Elizabeth J. , Ross‐Russell Robert , O'Keefe Peter , Weller Peter 
Published: August 2002

AbstractDry powder inhaler (DPI) devices are frequently used in children over 5 years of age in order to avoid coordination difficulties often seen with the use of pressurized metered dose inhalers (pMDI). This study assessed the efficacy, tolerability, and acceptability of salbutamol delivered via two delivery systems, in a population of pediatric patients. The primary aim of the study was to investigate the bronchodilator efficacy of a single dose (100 μg) of salbutamol administered via a dry powder inhaler (Clickhaler®) compared to a similar dose administered by a pressurized metered dose inhaler via a large‐valved holding chamber (VHC) to children with asthma. The study comprised two phases: the first comparator phase, followed by an open 4‐week treatment period.Sixty‐one children with a mean (SD) age of 11.3 years (2.9) (range, 6–17) and mild or moderate asthma completed the study. The primary efficacy endpoint, forced expiratory volume in 1 sec (FEV1), indicated that there was no clinically or statistically significant difference between the bronchodilator effects of salbutamol delivered via either device, with a maximum posttreatment percentage change in FEV1 (SD) of 12.4% (10.0) and 14.15 (9.3) for Clickhaler® and pMDI plus VHC, respectively. Most patients rated the Clickhaler as easy to use (97%) and liked the device (84%). Both treatments were well‐tolerated.These results support the suitability of salbutamol Clickhaler® as an acceptable, well‐tolerated, and effective alternative to a pMDI plus VHC in mild to moderate asthmatic children over age 6 years. Pediatr Pulmonol. 2002; 33:189–193. © 2002 Wiley‐Liss, Inc.
Intermediate cells in normal and malignant prostate epithelium express c‐MET: Implications for prostate cancer invasion
Authors: van Leenders Geert , van Balken Bianca , Aalders Tilly , Hulsbergen‐van de Kaa Christina , Ruiter Dirk , Schalken Jack 
Published: August 2002

AbstractBACKGROUNDAnalysis of keratin (K) expression discriminates luminal (K18) and intermediate (K5/18) cells in prostate carcinoma, while basal (K5/14) cells are absent. Intermediate cells have been proposed as targets of malignant transformation in prostate cancer and precursors of androgen‐independent tumor progression. We demonstrate localization of hepatocyte growth factor (HGF) receptor c‐MET in intermediate cells in both normal and malignant prostate epithelium.METHODSReceptor localization was analyzed using triple staining for c‐MET, K5, K14, and K18. The percentage of strongly c‐MET positive cells was determined in 15 prostate cancer patients undergoing androgen‐deprivation and 14 patients without neo‐adjuvant treatment. Effects of HGF were investigated on prostate cancer cell line DU145.RESULTSc‐MET expression in non‐malignant epithelium was strong in intermediate cells absent in differentiated cells, and heterogeneous in basal cells. In prostate cancer, intermediate cells displayed high c‐MET levels coupled with mild expression in differentiated cells. During androgen‐deprivation, 7.6% of tumor cells revealed high c‐MET expression compared to 1.7% without treatment (P = 0.02). Matrigel penetration of DU145 was 8.2 ± 1.7 mm2 after HGF stimulation compared to 3.6 ± 2.4 mm2 in controls (P < 0.02).CONCLUSIONSIntermediate cells in normal and malignant prostate epithelium express high c‐MET levels, indicating that they are prone to stromal invasion in prostate carcinoma. Prostate 51: 98–107, 2002. © 2002 Wiley‐Liss, Inc.
PEAZ‐1: A new human prostate neoplastic epithelial cell line
Authors: Schmelz Monika , Cress Anne E. , Barrera Jean , McDaniel Kathy M. , Davis Tracy L. , Fuchs Laura , Dalkin Bruce L. , Nagle Raymond B. 
Published: August 2002

AbstractBACKGROUNDThe generation of prostatic cell lines provides in vitro models for experimental studies of the pathogenesis of prostate carcinoma. Therefore, we established and characterized a new human prostate epithelial cell line, PEAZ‐1 (prostate epithelial Arizona‐1).METHODSThe PEAZ‐1 cells were grown from a primary human prostate carcinoma specimen obtained from radical prostatectomy. The isolated cells were characterized by immunobiochemistry, immunohistochemistry, and tumorigenicity studies.RESULTSPEAZ‐1 cells are near diploid, tumorigenic, and androgen independent for cell growth. PEAZ‐1 cells express N‐cadherin, α‐ and β‐catenins, and p120 at cell–cell contacts, cytoplasmic laminin 5, vinculin, paxillin, and phosphotyrosine at focal adhesions, vimentin, and cytokeratins 8 and 18. They do not express plakoglobin, E‐cadherin, and PSA, and do not form desmosomes and hemidesomomes. PEAZ‐1 respond to ocadaic acid, a pro‐apoptotic agent, by expression of p53.CONCLUSIONSPEAZ‐1 cells is a human prostate cancer cell line that has a number of mesenchymal characteristics. Prostate 48:79–92, 2001. © 2001 Wiley‐Liss, Inc.
Classification of proteins based on the properties of the ligand‐binding site: The case of adenine‐binding proteins
Authors: Cappello Valentina , Tramontano Anna , Koch Uwe 
Published: August 2002

AbstractComparative analysis of protein binding sites for similar ligands yields information about conserved interactions, relevant for ligand affinity, and variable interactions, which are important for specificity. The pattern of variability can indicate new targets for a pharmacologically validated class of compounds binding to a similar site. A particularly vast group of therapeutically interesting proteins using the same or similar substrates are those that bind adenine‐containing ligands. Drug development is focusing on compounds occupying the adenine‐binding site and their specificity is an issue of paramount importance. We use a simple scheme to characterize and classify the adenine‐binding sites in terms of their intermolecular interactions, and show that this classification does not necessarily correspond to protein classifications based on either sequence or structural similarity. We find that only a limited number of the different hydrogen bond patterns possible for adenine‐binding is used, which can be utilized as an effective classification scheme. Closely related protein families usually share similar hydrogen patterns, whereas non‐polar interactions are less well conserved. Our classification scheme can be used to select groups of proteins with a similar ligand‐binding site, thus facilitating the definition of the properties that can be exploited to design specific inhibitors. Proteins 2002;47:106–115. © 2002 Wiley‐Liss, Inc.
Population analyses of kinetic partitioning in protein folding
Authors: Nakamura Hironori K. , Sasai Masaki 
Published: August 2002

AbstractA simple lattice model of protein folding is studied in order to analyze the kinetic partitioning phenomena in the energy landscape perspective. By restricting the area of conformational space, it becomes possible to follow many Monte Carlo trajectories until they reach equilibrium. Alteration of population of trajectories is monitored and the relations between the energy landscape and kinetics are examined. Kinetic partitioning phenomena are categorized into different types in terms of characteristic time constants and partitioning ratio. In a specific partitioning process, refolding proceeds along the parallel pathways; the time constants have a temperature dependence similar to that observed in hen lysozyme. High‐energy conformations are classified into groups according to the probability that the trajectories starting from those conformations will reach each energy valley. The partitioning ratio is determined by the way in which the conformational space is organized into these groups. Proteins 2001;43:280–291. © 2001 Wiley‐Liss, Inc.
Structural implications of drug‐resistant mutants of HIV‐1 protease: High‐resolution crystal structures of the mutant protease/substrate analogue complexes
Authors: Mahalingam Bhuvaneshwari , Louis John M. , Hung Jason , Harrison Robert W. , Weber Irene T. 
Published: August 2002

AbstractEmergence of drug‐resistant mutants of HIV‐1 protease is an ongoing problem in the fight against AIDS. The mechanisms governing resistance are both complex and varied. We have determined crystal structures of HIV‐1 protease mutants, D30N, K45I, N88D, and L90M complexed with peptide inhibitor analogues of CA–p2 and p2–NC cleavage sites in the Gag–pol precursor in order to study the structural mechanisms underlying resistance. The structures were determined at 1.55–1.9‐Å resolution and compared with the wild‐type structure. The conformational disorder seen for most of the hydrophobic side‐chains around the inhibitor binding site indicates flexibility of binding. Eight water molecules are conserved in all 9 structures; their location suggests that they are important for catalysis as well as structural stability. Structural differences among the mutants were analyzed in relation to the observed changes in protease activity and stability. Mutant L90M shows steric contacts with the catalytic Asp25 that could destabilize the catalytic loop at the dimer interface, leading to its observed decreased dimer stability and activity. Mutant K45I reduces the mobility of the flap and the inhibitor and contributes to an enhancement in structural stability and activity. The side‐chain variations at residue 30 relative to wild‐type are the largest in D30N and the changes are consistent with the altered activity observed with peptide substrates. Polar interactions in D30N are maintained, in agreement with the observed urea sensitivity. The side‐chains of D30N and N88D are linked through a water molecule suggesting correlated changes at the two sites, as seen with clinical inhibitors. Structural changes seen in N88D are small; however, water molecules that mediate interactions between Asn88 and Thr74/Thr31/Asp30 in other complexes are missing in N88D. Proteins 2001;43:455–464. © 2001 Wiley‐Liss, Inc.