bluuebunny/crossref_metadata_2025_split huggingface dataset:
Axial correlation lengths for aromatic copolyesters
Authors: Wu Tzong‐Ming 
Published: August 2002

AbstractX‐ray methods were used to investigate the structure of Vectra® and Xydar® polyesters. Xydar® is based on the aromatic polyester prepared from p‐hydroxybenzoic acid (HBA), terephthalic acid, and biphenol. Vectra® consists of HBA and 2‐hydroxy‐6‐naphthoic acid. X‐ray fiber diagrams of these materials consist of a series of nonperiodic layer lines, which are consistent with a structure consisting of parallel chains of a random comonomer sequence. The meridional peak positions are predicted accurately for fully extended, infinite chains, and the observed and calculated intensities are also in reasonably good agreement. However, there is a less adequate match between the observed and calculated peak profiles, which are predicted to be much sharper than those observed. The latter agreement is improved with a model consisting of finite chain segments with a slightly nonlinear (sinuous) conformation. The best agreement for the observed peak profiles is obtained with an ordered segment length of 90 ± 6 Å and a sinuosity of g = 3.67 ± 0.08% for Vectra® fibers and with an ordered segment length of 104 ± 6 Å and a sinuosity of g = 3.33 ±0.08% for Xydar® fibers. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1839–1847, 2001
Adsorption of a single polymer chain on a surface: A molecular dynamics simulation study
Authors: Michel Andreas , Kreitmeier Stefan 
Published: August 2002

AbstractWe performed simulations of the physical adsorption of a single globular chain on a surface of hemispherical shape by means of molecular dynamics simulations. For the chain, we took advantage of a united atom model. Interactions within the chain were limited to stretching, bending, and torsional as well as nonbonded interactions between the nonadjacent atoms. The interaction between each chain element and the surface formation are reigned by a Lennard–Jones potential. In this article, we focused on differences in the behavior of the adsorbed globule to the free unadsorbed one particularly in two different zones of the immediate vicinity of the surface. There were strong indications for a localized acceleration of the dynamics as compared with the bulk that appears in an increase of trans–gauche switches. For explanation we came up with an adsorption scenario. Special attention was given to the shift of the percentage of trans and gauche conformations within the globule in dependence on the strength of the adsorption potential that might be related to crystallization or glass transition. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2333–2339, 2001
Cationic cure of epoxy resin initiated by methylanilinium salts as a latent thermal initiator
Authors: Park Soo‐Jin , Kim Taek‐Jin , Lee Jae‐Rock 
Published: August 2002

AbstractThe effect of the novel N‐crotyl‐N,N‐dimethyl‐4‐methylanilinium hexafluroantimonate (CMH) initiator on cure kinetics and rheological properties of diglycidylether of bisphenol A (DGEBA) epoxy cationic system was investigated. From DSC measurements of the DGEBA/CMH system, it was found that this system exhibited excellent thermal latent characteristics at a given temperature and revealed complex cure behavior as indicated by multiple exotherms. The conversion and conversion rate of the DGEBA/CMH system increased with increasing the concentration of initiator, attributed to the high activity of CMH. Viscoelastic properties during gel formation of DGEBA initiated by CMH were investigated by rheological techniques under isothermal conditions. The gel time obtained from the modulus crossover point t(G′) = G″ was affected by a high curing temperature and the concentration of CMH, resulting in a high degree of network formation in cationic polymerization. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2397–2406, 2001
Cancer and children: where are we coming from? Where are we going?
Authors: Patenaude Andrea Farkas , Last Bob 
Published: August 2002

AbstractThe past four decades have seen remarkable progress in the treatment of childhood cancer and changes in the social environment in which cancer in the family is experienced. Current research in pediatric psycho‐oncology focuses on psychosocial consequences of the disease and on differentiating which factors predict problematic versus positive outcomes in adjustment of the child and the family. The papers in this Special Issue reflect much of the recent developments in childhood psycho‐oncology as well as the challenges to come. Copyright © 2001 John Wiley & Sons, Ltd.
Diabetes mellitus and cystic fibrosis: Comparison of clinical parameters in patients treated with insulin versus oral glucose‐lowering agents
Authors: Rosenecker Joseph , Eichler Irmgard , Bärmeier Heike , von der Hardt Horst 
Published: August 2002

AbstractThe prevalence of cystic fibrosis‐related diabetes melltitus (CFRD) is increasing as patients with cystic fibrosis (CF) live longer. Because patients with CFRD are insulin‐deficient, the standard medical treatment is exogenous insulin. Sulfonylureas enhance insulin secretion by acting on a specific islet beta cell receptor. No data are available about the outcome of sulfonylurea treatment vs. insulin treatment. In this retrospective study, data from 45 patients with CFRD were analyzed regarding their clinical outcome as it related to the treatment protocol.The duration of DM treatment was 7.6 ± 4.6 years in the insulin‐treated group and 3.5 ± 2.0 years in the sulfonylurea group (n.s.). The age of CFRD diagnosis was significantly earlier in patients treated with insulin (n = 34) than in the patients treated with sulfonylurea (n = 11) (16.4 ± 3.6 vs. 24.2 ± 4.8 years, P < 0.001). No statistical differences were found between the two groups in the time of CF diagnosis, the most recent forced expired volume in 1 sec, forced vital capacity, Shwachman score, hemoglobin A1C levels, or weight for height index at the end of the study.Our data suggest that a subgroup of CFRD patients can be managed for a number of years with sulfonylurea, and that the clinical outcome was not different in this group compared with the insulin‐treated patients. Pediatr Pulmonol. 2001; 32:351–355. © 2001 Wiley‐Liss, Inc.
Inhibitors of apoptosis proteins in prostate cancer cell lines
Authors: McEleny Kevin R. , Watson R. William G. , Coffey Ronan N.T. , O'Neill Amanda J. , Fitzpatrick John M. 
Published: August 2002

AbstractBACKGROUNDThe caspases are the central executioners of apoptosis. The inhibitors of apoptosis proteins (IAPs) are a family of recently described caspase inhibitors. We hypothesised that tumor resistance to apoptosis could be due in part to IAP expression.METHODSThe expression of NAIP, cIAP‐1, cIAP‐2, XIAP, and survivin was investigated in the prostate cancer cell lines LNCaP, PC3, and DU145. RNase protection assays and Western blotting were used to assess RNA and protein expression. Apoptotic susceptibility was determined using etoposide and assessed by propidium iodide (PI) DNA incorporation using flow cytometry.RESULTSDU145 and PC3 cells were more resistant to apoptosis than LNCaP cells. All the IAPs were identified in the cell lines with variation in IAP expression between different cell types. Immunohistochemistry demonstrated cIAP‐1 expression in PC3 cells was nuclear, while the expression of cIAP‐2 and XIAP was perinuclear. Growing LNCaP cells in charcoal‐stripped or androgen‐supplemented medium resulted in no alteration in IAP expression.CONCLUSIONSThis study characterises the expression of IAP in three of the most commonly used prostate cancer cells. IAP may make an important contribution to apoptotic resistance in patients with prostate cancer. Prostate 51: 133–140, 2002. © 2002 Wiley‐Liss, Inc.
Androgen ablation promotes neuroendocrine cell differentiation in dog and human prostate
Authors: Ismail A Hazem R. , Landry France , Aprikian Armen G. , Chevalier Simone 
Published: August 2002

AbstractBACKGROUNDMechanisms triggering prostatic NE differentiation are poorly understood. Since dog and man naturally develop prostatic proliferative diseases with age, our objectives were to confirm the presence of NE cells in the dog prostate and test their hormonal regulation in both species.METHODSSerotonin staining was examined by immunohistochemistry in 37 dog prostates: 17 from intact and 20 from castrated animals. In intact dogs, 9 prostates were normal and 8 hyperplastic. In the castrated group, 6 dogs were left untreated while androgens and estrogens were administered to 7 dogs, each. Human prostates were from 48 prostate cancer patients; half of them were submitted to androgen ablation prior to prostatectomy. The density of serotonin‐positive NE cells was expressed relatively to the number of acini.RESULTSSerotonin‐positive NE cells were morphologically similar in dog and human prostates and identified in all groups, independent of the hormonal status. NE cell densities were within the same range in normal and hyperplastic dog prostates but significantly higher after castration. Androgens and estrogens after castration restored NE cell density to normal values and induced luminal differentiation and basal metaplasia, respectively. In human, the density of serotonin‐positive NE cells was also significantly higher in benign glands after androgen ablation.CONCLUSIONSThe dog is a suitable animal model and mimics the human, since androgen ablation favored prostatic NE differentiation in both species. The down‐regulation elicited by steroids suggests that the process may be reversible and hormonally‐repressed. Prostate 51: 117–125, 2002. © 2002 Wiley‐Liss, Inc.
Progesterone receptor expression in human prostate cancer: Correlation with tumor progression
Authors: Bonkhoff Helmut , Fixemer Thomas , Hunsicker Isabel , Remberger Klaus 
Published: August 2002

AbstractBACKGROUNDThe recent discovery of the classical estrogen receptor alpha (ERα) in metastatic and recurrent prostatic adenocarcinoma suggests that estrogens are implicated in prostate cancer progression.METHODSTo get more insight into estrogen signaling in prostate cancer tissue, the current study has examined the immunoprofile of the estrogen‐inducible progesterone receptor (PR), and evaluated its relation to ERα gene expression.RESULTSIn primary tumors, the PR was detectable in 36% of primary Gleason grade 3 (5 of 14 cases), 33% of primary Gleason grade 4 (5 of 15 cases), and in 58% of primary Gleason grade 5 tumors (7 of 12 cases). None of the 41 primary tumors investigated revealed significant PR expression in more than 50% of tumor cells. Conversely, moderate to strong receptor expression was observed in 60% of metastatic lesions (9 of 15 cases), and in 54% of androgen‐insensitive tumors (38 of 71 cases). Irrespective of grades and stages, the presence of the PR was invariably associated with high steady state levels of ERα mRNA, whereas the ERα protein was undetectable by immunohistochemistry (IHC) in a significant number of cases (58 of 97 cases).CONCLUSIONSThe progressive emergence of the PR during tumor progression obviously reflects the ability of metastatic and androgen‐insensitive tumors to use estrogens through a ERα‐mediated pathway. The present data provide a theoretical background for studying the efficiency of antiestrogens and antigestagens in the medical treatment of advanced prostate cancer. Prostate 48:285–291, 2001. © 2001 Wiley‐Liss, Inc.
Threading structural model of the manganese‐stabilizing protein PsbO reveals presence of two possible β‐sandwich domains
Authors: Pazos Florencio , Heredia Pedro , Valencia Alfonso , de las Rivas Javier 
Published: August 2002

AbstractThe manganese‐stabilizing protein (PsbO) is an essential component of photosystem II (PSII) and is present in all oxyphotosynthetic organisms. PsbO allows correct water splitting and oxygen evolution by stabilizing the reactions driven by the manganese cluster. Despite its important role, its structure and detailed functional mechanism are still unknown. In this article we propose a structural model based on fold recognition and molecular modeling. This model has additional support from a study of the distribution of characteristics of the PsbO sequence family, such as the distribution of conserved, apolar, tree‐determinants, and correlated positions. Our threading results consistently showed PsbO as an all‐beta (β) protein, with two homologous β domains of approximately 120 amino acids linked by a flexible Proline‐Glycine‐Glycine (PGG) motif. These features are compatible with a general elongated and flexible architecture, in which the two domains form a sandwich‐type structure with Greek key topology. The first domain is predicted to include 8 to 9 β‐strands, the second domain 6 to 7 β‐strands. An Ig‐like β‐sandwich structure was selected as a template to build the 3‐D model. The second domain has, between the strands, long‐loops rich in Pro and Gly that are difficult to model. One of these long loops includes a highly conserved region (between P148 and P174) and a short α‐helix (between E181 and N188)). These regions are characteristic parts of PsbO and show that the second domain is not so similar to the template. Overall, the model was able to account for much of the experimental data reported by several authors, and it would allow the detection of key residues and regions that are proposed in this article as essential for the structure and function of PsbO. Proteins 2001;45:372–381. © 2001 Wiley‐Liss, Inc.
Crystallographic dissection of the thermal motion of protein‐sugar complex
Authors: Harata Kazuaki , Kanai Ryuta 
Published: August 2002

AbstractThe crystal structure of turkey egg lysozyme (TEL) complexed with di‐N‐acetylchitobiose (NAG2) was refined at 1.19 Å resolution by the full‐matrix least‐squares method with anisotropic temperature factors, and its thermal motion was evaluated by the TLS method. The average ESDs of atomic parameters of nonhydrogen atoms were 0.030 Å for coordinates and 0.025 Å2 for anisotropic temperature factors. The active site cleft of TEL binds the α‐anomer of NAG2 in a nonproductive binding mode with its pyranose rings parallel to a β‐sheet. The TEL structure was compared with the re‐refined 1.12 Å structure of native TEL. The RMS difference for equivalent Cα atoms was 0.103 Å and a relatively large difference was observed in the region of residues 104–125 rather than in the β‐sheet region where NAG2 was bound. In contrast, the temperature factor of the β‐sheet region was significantly decreased by the NAG2 binding. The TLS model that describes the rigid body motion in translation, libration, and screw motion was adopted for the evaluation of the molecular motion of TEL and NAG2, and the TLS parameters were determined by the least‐squares fit to Uij. The contribution of the external motion of TEL was estimated to be 55.8% of the observed temperature factor for the native structure and 45.9% for the NAG2 complex. The internal motion of TEL represented with atomic thermal ellipsoids was very similar between the native and complex structures except the NAG2 binding region. In the structure of NAG2, the rigid body motion dominates the thermal motion. The center of rotation of NAG2, 4.45Å far from the center of gravity, is on the nitrogen atom of the acetylamino group that is hydrogen bonded to the main‐chain peptide groups of Asn49 and Ala107. The rigid body motion of NAG2 indicates that the acetylamino group is most strongly bound to the active site, and the recognition of this group is a crucial step of the substrate binding. Proteins 2002;48:53–62. © 2002 Wiley‐Liss, Inc.
Structure of the adenovirus E4 Orf6 protein predicted by fold recognition and comparative protein modeling
Authors: Brown Lawrence M. , Gonzalez Ramon A. , Novotny Jiri , Flint S.J. 
Published: August 2002

AbstractTo facilitate investigation of the molecular and biochemical functions of the adenovirus E4 Orf6 protein, we sought to derive three‐dimensional structural information using computational methods, particularly threading and comparative protein modeling. The amino acid sequence of the protein was used for secondary structure and hidden Markov model (HMM) analyses, and for fold recognition by the ProCeryon program. Six alternative models were generated from the top‐scoring folds identified by threading. These models were examined by 3D–1D analysis and evaluated in the light of available experimental evidence. The final model of the E4 protein derived from these and additional threading calculations was a chimera, with the tertiary structure of its C‐terminal 226 residues derived from a TIM barrel template and a mainly α‐nonbundle topology for its poorly conserved N‐terminal 68 residues. To assess the accuracy of this model, additional threading calculations were performed with E4 Orf6 sequences altered as in previous experimental studies. The proposed structural model is consistent with the reported secondary structure of a functionally important C‐terminal sequence and can account for the properties of proteins carrying alterations in functionally important sequences or of those that disrupt an unusual zinc‐coordination motif. Proteins 2001;44:97–109. © 2001 Wiley‐Liss, Inc.
Dynamics and mechanism of ultraviolet photolysis of atrazine on soil surface
Authors: Gong Ajun , Ye Changming , Wang Xingjun , Lei Zhifang , Liu Jianmiao 
Published: August 2002

AbstractThe photolysis of atrazine in the soil surface under UV light and the factors affecting this has been studied. A rate constant of 0.09–0.17 min−1, photolytic depth of 0.1–0.3 mm and half‐life of 4–8 min were determined. The results show that soil granularity, pH, humidity, organic content, humic acid and surface‐active agents could affect the photolysis of atrazine in soil. GC–MS showed three photolytic products: 1‐sec‐butyl‐4,4‐diethyl‐1‐tetrazene, N 2, N 4‐diethyl‐6‐methyl‐1,3,5‐triazine‐2,4‐diamine and 6‐chloro‐N 2‐propyl‐1,3,5‐triazine‐2,4‐diamine. The mechanism of the photolytic process is discussed.© 2001 Society of Chemical Industry
The aquatic fate of triclopyr in whole‐pond treatments
Authors: Petty David G , Skogerboe John G , Getsinger Kurt D , Foster Dale R , Houtman Bruce A , Fairchild James F , Anderson Lars W 
Published: August 2002

AbstractThe aquatic fate of the triethylamine salt formulation of triclopyr (3,5,6‐trichloro‐2‐pyridinyloxyacetic acid) was determined in whole‐pond applications in closed (no water exchange) systems in California, Missouri and Texas in two studies conducted in 1995 and 1996. These studies determined dissipation rates of triclopyr and its principal metabolites, 3,5,6‐trichloropyridinol (TCP) and 3,5,6‐trichloro‐2‐methoxypyridine (TMP) in water, sediment and finfish. Ponds at each site containing a healthy biological community were treated at 2.5 mg AE litre−1 triclopyr. Water and sediment samples were collected through 12 weeks post‐treatment, and non‐target animals were collected through 4 weeks post‐treatment. Dissipation rates for triclopyr, TCP and TMP were similar at each of the study sites, despite differences in weather, water quality, biotic community, light transmission and geographic location. Half‐lives of triclopyr in water ranged from 5.9 to 7.5 days, while those of TCP and TMP ranged from 4 to 8.8 and 4 to 10 days, respectively. Levels of triclopyr and TCP declined in sediments at half‐lives ranging from 2.8 to 4.6 days and 3.8 to 13.3 days, respectively. No TMP was detected in sediment. Triclopyr and TCP cleared from fish in relation to concentrations found in the water column. TMP levels in fish were generally an order of magnitude higher than levels of triclopyr and TCP, particularly in the visceral portion of the animals. No adverse effects on water quality or on the non‐target biotic community were found following triclopyr applications. Results of these studies were comparable to those of triclopyr dissipation studies conducted in reservoirs, lakes and riverine systems in Georgia, Florida, Minnesota and Washington, indicating that the degradation and dissipation of triclopyr and its metabolites are similar in representative systems throughout the USA.© 2001 Society of Chemical Industry
Synthesis and fungicidal activity of a series of novel aryloxylepidines
Authors: Kirby Neil V , Daeuble John F , Davis L Navelle , Hannum Anna C , Hellwig Karin , Lawler Lori K , Parker Marshall H , Pieczko Mary E 
Published: August 2002

AbstractA series of novel (hetero)aryloxylepidine derivatives was devised as hybrid structures of the phenoxyquinoline and phenethoxyquin(az)oline fungicides. Synthesis of these targets required the development of several new routes to derivatised 4‐hydroxymethylquinolines, and subsequent coupling with phenols or haloarenes. The aryloxylepidines generally showed moderate broad‐spectrum fungicidal activity across several diseases of cereals. Substitution of the quinoline ring with chlorine at the 7‐ and/or 5‐positions gave molecules with high levels of protectant activity against Erysiphe graminis f sp tritici (powdery mildew of wheat), but this did not improve the level of fungicidal activity against other diseases. In vitro activity against mitochondrial electron transport complex I (MET) derived from Ustilago maydis showed that 8‐fluorolepidine analogues were moderately active at this target site, while the more fungicidally active 7‐ and 5,7‐substituted compounds were inactive. This indicates that MET is not the primary target of these highly active powdery mildewicides.© 2001 Society of Chemical Industry
Photolysis of fluchloralin in aqueous methanol
Authors: Saha Tapas , Bhattacharyya Anjan 
Published: August 2002

AbstractThe photodegradation of fluchloralin by UV irradiation or sunlight in aqueous methanolic solution has been examined. In the presence of titanium dioxide five photoproducts were obtained, but only four in its absence. One photoproduct, 2, 2′‐azoxy‐bis(α,α,α‐trifluoro‐6‐nitro‐p‐toluidine) is reported for the first time as a metabolite of fluchloralin. In natural sunlight the rate of degradation was higher than in UV light and titanium dioxide had almost no effect on the rate of degradation.© 2001 Society of Chemical Industry
Cu(OBt)2 and Cu(OAt)2, copper(II)‐based racemization suppressors ready for use in fully automated solid‐phase peptide synthesis
Authors: Van Den Nest Wim , Yuval Shov , Albericio Fernando 
Published: August 2002

AbstractThe complexes Cu(OBt)2 and Cu(OAt)2, which are derived from copper(II) and HOBt and HOAt, respectively, are shown to be more effective in suppressing racemization during solid‐phase peptide synthesis (SPPS) than are those compounds currently being used for this purpose. These compounds can readily be used in conjunction with the commonly applied coupling reagents in fully automated systems for solid‐phase peptide chemistry. Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd.