bluuebunny/crossref_metadata_2025_split huggingface dataset:
Superdrawing of polytetrafluoroethylene virgin powder above the static melting temperature
Authors: Endo Ryokei , Kanamoto Tetsuo 
Published: August 2002

AbstractA new two‐stage draw technique was successfully applied to the superdrawing of polytetrafluoroethylene (PTFE) virgin powder. A film, compression‐molded from powder below the melting temperature (Tm = 335 °C), was initially solid‐state coextruded to an extrusion draw ratio (EDR) of 6–20 at 325 °C, about 10 °C below the Tm. These extrudates from the first‐stage draw were further drawn by a second‐stage pin draw in the temperature (Td) range of 300–370 °C that covers the static Tm. The maximum achievable total draw ratio was ∼60 at a Td = 300 °C and increased rapidly with increasing Td, reaching a maximum of 100–160 at a temperature window between 340 and 360 °C, depending on the initial EDRs. At yet higher Td's, the ductility was lost as a result of melting. The high ductility of the PTFE extrudates at such high temperatures was ascribed to the improvement of interfacial adhesion and bonding between the deformed powder particles upon the first‐stage extrusion combined with the rapid heating of only a portion of the extrudate followed by the elongation at a high rate. The highly drawn fibers were highly crystalline (χc ≤ 87%) and showed high chain orientation (fc ≤ 0.997) and a large crystallite size along the chain axis (D0015 ≤ 160 nm). The molecular draw ratio, estimated from the entropic shrinkage above the Tm, was close to the macroscopic deformation ratio independently of the initial EDRs. These results indicate that the draw was highly efficient in terms of chain extension, orientation, and crystallization. Thus, the maximum tensile modulus and strength achieved in this work were 102 ± 5 and 1.4 ± 0.2 GPa, respectively, at 24 °C. These tensile properties are among the highest ever reported on oriented PTFE. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1995–2004, 2001
Spinodal decomposition in N‐isopropylacrylamide gel
Authors: Hu Zhibing , Wang Changjie , Chen Yuanye , Zhang Xiaomin , Li Yong 
Published: August 2002

AbstractSpinodal decomposition in a chemically crosslinked N‐isopropylacrylamide (NIPA) polymer gel was investigated using turbidity and ultrasonic techniques. The turbidity of the quenched NIPA gel was measured over five orders of magnitude of timescales. With an increase of time, the gel transfers from a transparent and swollen gel to a cloudy and inhomogeneous gel, and eventually to a transparent and collapsed gel. The first transformation is a rapid process that only involves local arrangement of the polymer network and solvent into dilute and dense domains. The second transformation is a very slow process that involves global arrangement of the polymer network and solvent. The characteristic time for disappearance of the turbidity is proportional to the linear size squared at a constant temperature above Tc and increases exponentially as a function of the quenching depth of T − Tc. By probing the movement of domains, a possible time‐dependent gel structure in the spinodal decomposition region is presented. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2168–2174, 2001
Maximizing the grain growth rate during the disorder‐to‐order transition in block copolymer melts
Authors: Kim W. G. , Garetz B. A. , Newstein M. C. , Balsara N. P. 
Published: August 2002

AbstractThe factors controlling grain growth during the disorder‐to‐order transition in a polystyrene‐block‐polyisoprene copolymer melt were studied with time‐resolved depolarized light scattering. The ordered phase consisted of hexagonally packed polyisoprene cylinders, and the order–disorder‐transition temperature of the block copolymer (TODT) was 132 ± 1 °C. Our objective was to identify the temperature at which the grain growth rate was maximized (Tmax) and compare it with theoretical predictions. We conducted seeded grain growth experiments, which comprised two steps. In the first step, which lasted for 43 min, the sample was cooled from the disordered state to 124 °C. This resulted in the formation of a small number of ordered grains or seeds. This was followed by a second step in which the sample was heated to temperatures between 124 and 132 °C and the seeds grew with time. Our objective was to study grain growth at different temperatures starting from the same initial condition. The value of Tmax obtained experimentally was 128 °C. The theoretically predicted value of Tmax, based entirely on the rheological properties of the disordered sample and TODT, was also 128 °C. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2231–2242, 2001
The system of belief inventory (SBI‐15): a validation study in Israel
Authors: Baider Lea , Holland Jimmie C. , Russak Simcha M. , Kaplan De‐Nour Atara 
Published: August 2002

AbstractThis study focused on the validation of measures assessing religiosity by means of three self‐report instruments: the System of Belief Inventory (SBI‐15R), the Religious Orientation Inventory (ROI), and the Index of Core Spiritual Experiences (INSPIRIT). These instruments were developed and validated previously in the United States.The study measured the extent to which the self‐reports maintain their validity when administered in a different country with its own distinct language, culture and religion (e.g. Israel).It was found that all three self‐reports have very good external validity and high convergent reliability, with the SBI demonstrating extremely high internal reliability. Copyright © 2001 John Wiley & Sons, Ltd.
Changes in arterial oxygen tension when weaning neonates from inhaled nitric oxide*†
Authors: Sokol Gregory M. , Fineberg Naomi S. , Wright Linda L. , Ehrenkranz Richard A. 
Published: August 2002

AbstractWe set out to evaluate changes in arterial oxygen tension (PaO2) when weaning neonates from inhaled nitric oxide (INO). We reviewed the records of 505 prospectively collected INO weaning attempts on 84 neonates with hypoxic respiratory failure. PaO2 values before and 30 min after weaning attempts were recorded. Relationships between change in PaO2 and decreases in INO concentrations were investigated using regression analysis and ANOVA.PaO2 decreased (−18.7 ± 1.8 torr; P < 0.001); when weaning INO. A stepwise decline in PaO2 was observed weaning INO from 40 ppm. The greatest decline occurred when INO was discontinued (−42.1 ± 4.1 torr). Forward stepwise multiple regression using variables with significant relationships to the decline in PaO2 identified the specific dose reduction 7(P < 0.001), the prewean PaO2 (P < 0.001), and surfactant therapy (P = 0.018) as the variables best describing the change in PaO2(P = 0.004, r = 0.51).In conclusion, a graded decline in PaO2 occurs when reducing INO. INO should be weaned to less than 1 ppm before discontinuing its use. Prior surfactant treatment appears to enhance the oxygenation reserve when weaning INO. Pediatr Pulmonol. 2001; 32:14–19. © 2001 Wiley‐Liss,Inc.
Effect of clarithromycin on airway obstruction and inflammatory markers in induced sputum in cystic fibrosis: A pilot study*
Authors: Ordoñez Claudia L. , Stulbarg Michael , Grundland H. , Liu Jane T. , Boushey Homer A. 
Published: August 2002

AbstractTo determine whether macrolide antibiotics improve pulmonary function and decrease airway inflammation in cystic fibrosis (CF), we treated 10 patients (females; aged 19–26 years, all colonized with P. aeruginosa, none with atypical Mycobacteria) with 3 weeks of placebo, followed by 6 weeks of clarithromycin (500 mg BID) in a single‐blind prospective study. We also determined the safety of sputum induction and the reproducibility of assessing inflammatory markers in induced sputum. Subjects performed spirometry and underwent sputum induction (12‐min inhalation of 3% saline) at 3‐week intervals.We found that sputum induction was well‐tolerated. We also found that the reproducibility was high for neutrophil (PMN) number (R = 0.87, P = 0.009), interleukin (IL)‐8 (R = 0.73, P < 0.05, free neutrophil elastase (NE) (R = 0.82, P < 0.05), and myeloperoxidase (MPO) levels (R = 0.86, P < 0.05), but was less so for tumor necrosis factor (TNF)‐α (R = −0.15, P = 0.7). We found no significant difference in pulmonary function after 6 weeks of treatment with clarithromycin (FEV1 (% predicted) (mean ± SEM), 2.2 ± 0.9 (60 ± 24%) vs. 2.3 ± 1 (61 ± 29%)), and no significant differences in any of the inflammatory indices measured. The median (and range) values before and after treatment for indices of airway inflammation in the induced sputum samples were: for PMNs, 8 (1–326) and 21 (0.2 –175) × 106 cells/mL sputum; for IL‐8, 156 (24–656) and 202 (16–680) ng/mL; for free NE, 260 (31–1,264) and 237 (49–1,048) μg/mL; for TNF‐α, 20 (7–128) and 35 (17–87) pg/mL; and for MPO, 169 (13–960) and 195 (14–816) μg/mL.We conclude that clarithromycin is not uniformly effective in improving airway obstruction or in decreasing airway inflammation in patients with CF. Pediatr Pulmonol. 2001; 32:29–37. © 2001 Wiley‐Liss, Inc.
Overexpression of the homeobox gene HOXC8 in human prostate cancer correlates with loss of tumor differentiation*
Authors: Waltregny David , Alami Younes , Clausse Nathalie , Leval Jean de , Castronovo Vincent 
Published: August 2002

AbstractBACKGROUNDHomeobox (HOX)‐containing proteins have been identified as regulators controlling the coordinated expression of genes involved in development and differentiation. Recent data also suggest a possible involvement of HOX genes in malignant transformation and/or progression. We have previously shown that HOXC8 expression was selectively turned on in human cervix cancer cells compared with normal keratinocytes, suggesting that HOXC8 may be involved in the process leading to the transformation of cervix keratinocytes [Alami et al.: Biochem Biophys Res Commun 257:738–745, 1999].METHODSRT‐PCR and in situ hybridization experiments were performed to investigate the expression and cell type localization of HOXC8 transcripts in human prostate cancer cell lines and tissues. In situ hybridization was performed with the use of an HOXC8 anti‐sense digoxigenin‐labeled probe to investigate HOXC8 mRNA expression in 27 prostate cancer tissue specimens.RESULTSOut of the three human prostate cancer cell lines tested, DU‐145 and PC3 but not LNCaP cells expressed detectable amount of HOXC8 transcripts. Results from in situ hybridization experiments demonstrated that HOXC8 gene was expressed mainly in malignant epithelial cells. Furthermore, the staining intensity in epithelial cells was significantly increased in high Gleason score carcinomas (scores 7–9, n = 12; labeling intensity 2 + to 3 +) compared with the one observed in low and intermediate Gleason score tumors (scores 3–6, n = 15; labeling intensity 0 and 1 +) (ANOVA test, P < 0.0001).CONCLUSIONSOur data showing that HOXC8 overexpression is associated with the loss of tumor differentiation in human prostate cancer suggests that HOXC8 may play a role in the acquisition of the invasive and metastatic phenotype of this malignancy. Prostate 50: 162–169, 2002. © 2002 Wiley‐Liss, Inc.
Down‐regulation of prostasin serine protease: A potential invasion suppressor in prostate cancer
Authors: Chen Li‐Mei , Hodge G. Byron , Guarda Luis A. , Welch James L. , Greenberg Norman M. , Chai Karl X. 
Published: August 2002

AbstractBACKGROUNDProstasin is a serine protease predominantly expressed in normal prostate epithelial cells. The biological function of prostasin has not been determined.METHODSWestern blot and RT‐PCR analyses were used to examine the expression of prostasin in prostate cancer cell lines. Immunohistochemistry was used to evaluate prostasin protein expression in human prostate cancer. An in vitro Matrigel invasion assay was used to test the invasiveness of prostate cancer cell lines forced to express recombinant prostasin.RESULTSBoth prostasin protein and mRNA were found to be expressed in normal human prostate epithelial cells and a non‐invasive human prostate cancer cell line, the LNCaP, but neither was found in invasive human prostate cancer cell lines DU‐145 and PC‐3. Prostasin mRNA expression was absent in invasive prostate cancer cell lines of a transgenic mouse model. Immunohistochemistry analysis showed that prostasin protein expression is down‐regulated in high‐grade prostate cancer. Transfection of DU‐145 and PC‐3 cells with a full‐length human prostasin cDNA restored prostasin expression and reduced the in vitro invasiveness by 68 and 42%, respectively.CONCLUSIONSOur data indicate that prostasin may be implicated in normal prostate biology and is able to suppress prostate cancer invasion in vitro. Prostate 48:93–103, 2001. © 2001 Wiley‐Liss, Inc.
How accurately does prostate biopsy Gleason score predict pathologic findings and disease free survival?
Authors: Narain Vivek , Bianco Fernando J. , Grignon David J. , Sakr Wael A. , Pontes J. Edson , Wood David P. 
Published: August 2002

AbstractObjectiveDue to the significant impact on prognosis by subgrouping of prostatectomy Gleason scores < 7, 7, and > 7, we undertook this study to answer whether the biopsy Gleason score was as predictive of disease free survival and assess the correlation with the prostatectomy Gleason score in a modern prostatectomy series.MethodsAn analysis of 1,031 patients who underwent radical prostatectomy for clinically localized prostate cancer was performed. All data was prospectively collected. The Gleason score was categorized into 3 different groups (< 7, 7, and > 7) for biopsy and prostatectomy specimens. Disease free survival was then analyzed for each group. Discrepancies between scores and outcomes were evaluated.ResultsAccurate correlation was noted in 54.8, 66.8, and 47.4% of Gleason scores < 7, 7, and > 7, respectively. Overall accuracy was 58.3%. Both, biopsy and prostatectomy Gleason score correlated significantly with disease free survival (P = 0.001), furthermore the classification (Gleason scores < 7, 7 and > 7) was highly significant (P = 0.001). Patients with prostatectomy Gleason < 7 tumors had significant survival advantage over those with biopsy Gleason < 7, (P = 0.001). However, disease free survival was superior for patients with biopsy Gleason > 7 than those with prostatectomy Gleason > 7, (P = 0.02). The overall disease free survival was similar among the patients with Gleason score of 7 (P = 0.12).ConclusionsIt appears that biopsy Gleason score, although oftentimes not correlating strongly with the prostatectomy Gleason score, is an important prognostic factor in prostate cancer. There are significant differences in disease free survival between biopsy and prostatectomy Gleason score categories. Prostate 49:185–190, 2001. © 2001 Wiley‐Liss, Inc.
Positioning of anchor groups in protein loop prediction: The importance of solvent accessibility and secondary structure elements
Authors: Wohlfahrt Gerd , Hangoc Vu , Schomburg Dietmar 
Published: August 2002

AbstractThe prediction of loop regions in the process of protein structure prediction by homology is still an unsolved problem. In an earlier publication, we could show that the correct placement of the amino acids serving as an anchor group to be connected by a loop fragment with a predicted geometry is a highly important step and an essential requirement within the process (Lessel and Schomburg, Proteins 1999;37:56–64). In this article, we present an analysis of the quality of possible loop predictions with respect to gap length, fragment length, amino acid type, secondary structure, and solvent accessibility. For 550 insertions and 544 deletions, we test all possible positions for anchor groups with an inserted loop of a length between 3 and 12 amino acids. We could show that approximately 80% of the indel regions could be predicted within 1.5 Å RMSD from a knowledge‐based loop data base if criteria for the correct localization of anchor groups could be found and the loops can be sorted correctly. From our analysis, several conclusions regarding the optimal placement of anchor groups become obvious: (1) The correct placement of anchor groups is even more important for longer gap lengths, (2) medium length fragments (length 5–8) perform better than short or long ones, (3) the placement of anchor groups at hydrophobic amino acids gives a higher chance to include the best possible loop, (4) anchor groups within secondary structure elements, in particular β‐sheets are suitable, (5) amino acids with lower solvent accessibility are better anchor group. A preliminary test using a combination of the anchor group positioning criteria deduced from our analysis shows very promising results. Proteins 2002;47:370–378. © 2002 Wiley‐Liss, Inc.
Structural basis of oncogenic activation caused by point mutations in the kinase domain of the MET proto‐oncogene: Modeling studies
Authors: Miller Maria , Ginalski Krzysztof , Lesyng Bogdan , Nakaigawa Noboru , Schmidt Laura , Zbar Berton 
Published: August 2002

AbstractMissense mutations in the tyrosine kinase domain of the MET proto‐oncogene occur in selected cases of papillary renal carcinoma. In biochemical and biological assays, these mutations produced constitutive activation of the MET kinase and led to tumor formation in nude mice. Some mutations caused transformation of NIH 3T3 cells. To elucidate the mechanism of ligand‐independent MET kinase activation by point mutations, we constructed several 3D models of the wild‐type and mutated MET catalytic core domains. Analysis of these structures showed that some mutations (e.g., V1110I, Y1248H/D/C, M1268T) directly alter contacts between residues from the activation loop in its inhibitory conformation and those from the main body of the catalytic domain; others (e.g., M1149T, L1213V) increase flexibility at the critical points of the tertiary structure and facilitate subdomain movements. Mutation D1246N plays a role in stabilizing the active form of the enzyme. Mutation M1268T affects the S+1 and S+3 substrate‐binding pockets. Models implicate that although these changes do not compromise the affinity toward the C‐terminal autophosphorylation site of the MET protein, they allow for binding of the substrate for the c‐Abl tyrosine kinase. We provide biochemical data supporting this observation. Mutation L1213V affects the conformation of Tyr1212 in the active form of MET. Several somatic mutations are clustered at the surface of the catalytic domain in close vicinity of the probable location of the MET C‐terminal docking site for cytoplasmic effectors. Proteins 2001;44:32–43. © 2001 Wiley‐Liss, Inc.
Protein flexibility predictions using graph theory
Authors: Jacobs Donald J. , Rader A.J. , Kuhn Leslie A. , Thorpe M.F. 
Published: August 2002

AbstractTechniques from graph theory are applied to analyze the bond networks in proteins and identify the flexible and rigid regions. The bond network consists of distance constraints defined by the covalent and hydrogen bonds and salt bridges in the protein, identified by geometric and energetic criteria. We use an algorithm that counts the degrees of freedom within this constraint network and that identifies all the rigid and flexible substructures in the protein, including overconstrained regions (with more crosslinking bonds than are needed to rigidify the region) and underconstrained or flexible regions, in which dihedral bond rotations can occur. The number of extra constraints or remaining degrees of bond‐rotational freedom within a substructure quantifies its relative rigidity/flexibility and provides a flexibility index for each bond in the structure. This novel computational procedure, first used in the analysis of glassy materials, is approximately a million times faster than molecular dynamics simulations and captures the essential conformational flexibility of the protein main and side‐chains from analysis of a single, static three‐dimensional structure. This approach is demonstrated by comparison with experimental measures of flexibility for three proteins in which hinge and loop motion are essential for biological function: HIV protease, adenylate kinase, and dihydrofolate reductase. Proteins 2001;44:150–165. © 2001 Wiley‐Liss, Inc.
Role of the carboxy‐termini of tubulin on its chaperone‐like activity
Authors: Sarkar Taradas , Manna Tapas , Bhattacharyya Shankar , Mahapatra Pradip , Poddar Asim , Roy Siddhartha , Pena Jose , Solana Rafael , Tarazona Raquel , Bhattacharyya Bhabatarak 
Published: August 2002

AbstractMutational analysis and the enzymatic digestion of many chaperones indicate the importance of both hydrophobic and hydrophilic residues for their unique property. Thus, the chaperone activity of α‐crystallin is lost due to the substitution of hydrophobic residues or upon enzymatic digestion of the negatively charged residues. Tubulin, an eukaryotic cytoskeletal protein, exhibits chaperone‐like activity as demonstrated by prevention of DTT‐induced aggregation of insulin, thermal aggregation of alcohol dehydrogenase, βγ‐crystallin, and other proteins. We have shown that the tubulin lost its chaperone‐like activity upon digestion of its negatively charged C‐termini. In this article, the role of the C‐terminus of individual subunits has been investigated. We observe that the digestion of C‐terminus of β‐subunit with subtilisin causes loss of chaperone‐like activity of tubulin. The contribution of C‐terminus of α‐subunit is difficult to establish directly as subtilisin cleaves C‐terminus of β‐subunit first. This has been ascertained indirectly using a 14‐residue peptide P2 having the sequence corresponding to a conserved region of MHC class I molecules and that binds tightly to the C‐terminus of α‐subunit. We have shown that the binding of P2 peptide to αβ‐tubulin causes complete loss of its chaperone‐like activity. NMR and gel‐electrophoresis studies indicate that the P2 peptide has a significant higher binding affinity for the C‐terminus of α‐subunit compared to that of β‐subunit. Thus, we conclude that both the C‐termini are necessary for the chaperone‐like activity of tubulin. Implications for the chaperone functions in vivo have been discussed. Proteins 2001;44:262–269. © 2001 Wiley‐Liss, Inc.
Bias‐free separation of internal and overall motion of biomolecules
Authors: Schieborr Ulrich , Rüterjans Heinz 
Published: August 2002

AbstractCollective internal motions are known to be important for the function of biological macromolecules. It has been discussed in the past whether the application of superimposing algorithms to remove the overall motion from a structural ensemble introduces artificial correlations between distant atoms. Here we present a new method to eliminate residual rotation and translation from cartesian modes derived from a normal mode analysis or from a principal component analysis. Bias‐free separation is based on the idea that the addition of modes of pure rotation/translation can compensate the residual overall motion. Removal of overall motion must reduce the “total amount of motion” (TAM) in the mode. Our algorithm allows to back‐calculate revised covariance matrices. The approach was applied to two model systems that show residual overall motion, when analyzed using all atoms as reference for the superimposing algorithm. In both cases, our algorithm was capable of eliminating residual covariances caused by the overall motion, while retaining internal covariances even for very distant atoms. A structural ensemble obtained for a 13‐ns molecular dynamics simulation of the protein Ribonuclease T1 showed a covariance matrix of the corrected modes with significantly sharper contours after applying the bias‐free separation. Proteins 2001;45:207–218. © 2001 Wiley‐Liss, Inc.