bluuebunny/crossref_metadata_2025_split huggingface dataset:
Syndiospecific living polymerization of 4‐methylstyrene and styrene with (trimethyl)pentamethylcyclopentadienyltitanium/tris(pentafluorophenyl)borane/trioctylaluminum catalytic system
Authors: Kawabe Masanao , Murata Masahide 
Published: August 2002

AbstractThe polymerizations of styrene and 4‐methylstyrene (4MS) with a half‐metallocene type catalytic system composed of (trimethyl)pentamethylcyclopentadienyltitanium (Cp*TiMe3), trioctylaluminum (AlOct3), and tris(pentafluorophenyl)borane [B(C6F5)3] were investigated at −25 °C. The addition of AlOct3as a third component of the catalytic system is effective both to promote the syndiospecific polymerization and to inhibit the nonstereospecific polymerization at the low‐temperature region. The use of AlOct3was also effective to eliminate the chain transfer reaction to alkylaluminum. The number‐average molecular weights (Mn's) of poly(4MS) or polystyrene increased proportionally with increasing monomer conversion. The molecular weight distribution (MWD) of polymer stayed narrow [Mw/Mn= ∼ 1.1 for poly(4MS) andMw/Mn= ∼ 1.5 for polystyrene]. It was thus concluded that the polymerizations of the styrenic monomers with Cp*TiMe3/B(C6F5)3/AlOct3catalytic system proceeded under living fashion at −25 °C. The living random copolymerization behaviors of styrene and 4MS were also confirmed. The13C NMR analysis clarified that each of the homopolymers and random copolymers obtained in this work had highly syndiotactic structure. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3692–3706, 2001
Synthesis and electroluminescent studies of blue‐emitting copolymers containing phenylene vinylene and oxadiazole moieties in the main chain
Authors: Zheng Min , Ding Liming , Elif Gürel E. , Karasz Frank E. 
Published: August 2002

AbstractTwo statistical copolymers III and IV combining features of the two reference polymers I and II were synthesized by a Wittig reaction with the objective of raising the electron‐transport properties and fluorescence quantum yields relative to the alternating block copolymers I and II. The electroluminescent properties of single‐layer LEDs using these copolymers were studied. External quantum efficiencies of 0.035 and 0.11% were obtained from single‐layer devices on the basis of III and IV, respectively, which are higher than those of similar devices using I and II. Two single‐layer LEDs using a blend of I and II (4:1 and 1:1 wt/wt) corresponding to the compositions of copolymers III and IV, respectively, were also fabricated for comparison. Results indicated that the covalent incorporation of oxadiazole is effective in improving the efficiency of LEDs and that the molar content of oxadiazole plays an important role in the performance of the devices. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 235–241, 2002
Polylactones. LVIII. Star‐shaped polylactones with functional end groups via ring‐expansion polymerization with a spiroinitiator
Authors: Kricheldorf Hans R. , Fechner Björn 
Published: August 2002

AbstractTwo more or less ethoxylated pentaerythritols were reacted with dibutyltin dimethoxide and yielded spirocyclic tin alkoxides that were soluble in hot toluene or in chlorobenzene, chloroform, and 1,1,2,2‐tetrachloroethane at room temperature. These solutions were used in situ as initiators for the ring‐expansion polymerization of ϵ‐caprolactone or β‐D,L‐butyrolactone. The spirocyclic polylactones were reacted with various carboxylic acid chlorides and yielded four‐armed stars with the elimination of Bu2SnCl2. By variation of the acid chlorides, star arms with chloroacetate, 4‐bromobenzoate, 4‐nitrobenzoate, cinnamate, stearate, or methacrylate end groups were obtained. With 4‐chlorothiophenyl esters of N‐protected amino acids, N‐protected aminoacyl end groups were introduced. A complete functionalization of all star arms was not achieved in all cases, and structure–property relationships were examined. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1047–1057, 2002
Lessons learned from research on photorefractive polymers and molecular materials
Authors: Yu Luping 
Published: August 2002

AbstractOrganic photorefractive (PR) materials are a new kind of electrooptic substance that emerged 10 years ago. These are very complicated materials that possess both electrooptic effects and photoconductivity. It is challenging to integrate these properties into a single polymer system that will exhibit this PR effect. This article highlights our efforts in the past nine years in synthesizing and characterizing fully functionalized organic PR materials. I emphasize the lessons we have learned from this research, which may be more valuable to those who are interested in this area. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2557–2564, 2001
Deformation of lamellar structures: Simultaneous small‐ and wide‐angle X‐ray scattering studies of polyamide‐6
Authors: Murthy N. S. , Grubb D. T. 
Published: August 2002

AbstractStructural changes during tensile deformation in semicrystalline polymers are studied by the analysis of both small‐ and wide‐angle X‐ray scattering data from polyamide‐6 fibers. The strain in the lamellar spacing is about the same as or higher than the fiber strain, suggesting that fiber elongation occurs by the deformation of the lamellar stack rather than slippage of the fibrils, especially during initial stages of elongation. The modulus of the lamellar structure is approximately 5 GN/m2, and this is close to the fiber modulus, which is only 2–3% of the crystal modulus. Fiber modulus is, therefore, determined by the lamellar structure as much as by the interfibrillar oriented chain segments. The four‐point small‐angle X‐ray scattering pattern in the relaxed fiber transforms reversibly into a two‐point pattern under strain. The structures that correspond to these two patterns, the bistable states of the lamellae, coexist until fiber breakage. The structure that gives rise to the two‐point pattern determines the ultimate strength of the fiber. Despite the small crystalline strain in the fiber direction, it is possible to follow the almost fully reversible changes in the orientation, size, and unit cell of the lamellar crystals. It is proposed that the appearance of the two‐point pattern, the decrease in the lateral crystallite size, and the increase in the stack diameter are due to tilting of the lamellar surface caused by large‐scale reversible strain in the interlamellar amorphous regions. This tilt is accomplished by slippage of the hydrogen‐bonded sheets along the chain axis. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 691–705, 2002
Phase equilibrium and diffusion of solvents in polybutadiene: A capillary‐column inverse gas chromatography study
Authors: Cai W. D. , Ramesh N. , Tihminlioglu F. , Danner R. P. , Duda J. L. , DèHaan A. 
Published: August 2002

AbstractThe capillary‐column inverse gas chromatography method was used to measure the diffusion and partition coefficients of ethylbenzene, styrene, and acrylonitrile in polybutadiene (PBD) at infinite dilution of the solvents. Experiments were performed over a temperature range of 50–125 °C. At temperatures well above the glass‐transition temperature of PBD, the diffusivities were correlated using an Arrhenius expression. The Arrhenius parameters in turn were intercorrelated and shown to be a function of the occupied volume, thus providing a method for predicting the diffusion of other solvents in the same polymer. Further, the activation energy was predicted using the Duda‐Vrentas free‐volume approach. The activation energy thus obtained was compared with the activation energy of the Arrhenius approach. The weight‐fraction activity coefficient data were compared to the predictions of the group contribution, lattice‐fluid equation‐of‐state, and the UNIquac Functional‐group Activity Coefficient (UNIFAC) free‐volume models. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1046–1055, 2002
Influence of deformation on irreversible and reversible crystallization of poly(ethylene‐co‐1‐octene)
Authors: Androsch R. , Wunderlich B. , Lüpke T. , Wutzler A. 
Published: August 2002

AbstractThe effect of uniaxial deformation and subsequent relaxation at ambient temperature on irreversible and reversible crystallization of homogeneous poly(ethylene‐co‐1‐octene) with 38 mol % 1‐octene melt‐crystallized at 10 K min was explored by calorimetry, X‐ray scattering, and Fourier transform infrared spectroscopy. At 298 K, the enthalpy‐based crystallinity of annealed specimens increased irreversibly by stress‐induced crystallization from initially 15% to a maximum of, at least, 19% when a permanent set of more than 200% was attained. The crystallinity increased by formation of crystals of pseudohexagonal structure at the expense of the amorphous polymer, and as a result of destruction of orthorhombic crystals. The stress‐induced increase of crystallinity was accompanied by an increase in the apparent specific heat capacity from 2.44 to about 2.59 J g−1 K−1, which corresponds to an increase of the total reversibility of crystallization from, at least, 0.10 to 0.17% K−1. The specific reversibility calculated for 100% crystallinity increased from 0.67 to 0.89% K−1 and points to a changed local equilibrium at the interface between the crystal and amorphous phases. The deformation resulted in typical changes of the phase structure and crystal morphology that involve orientation and destruction of crystals as well as the formation of fibrils. The effect of the decrease of the entropy of the strained melt on the reversibility of crystallization and melting is discussed. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1223–1235, 2002
Dielectric relaxation analysis of cellulose oligomers and polymers in dependency on their chain length
Authors: Meißner Dana , Einfeldt Lars , Einfeldt Jürgen 
Published: August 2002

AbstractFor all cellulose‐like oligo‐ and polyglucans, beginning with the dimer cellobiose, a broad relaxation process at low temperatures is observed using the dielectric relaxation spectroscopy method. This relaxation has its molecular origin in orientational motions of the sugar rings via the glucosidic linkages. We investigated the dynamics of this main chain motion for β(1‐4) oligoglucans with 2, 3, 4, or 5 anhydroglucose units (AGUs), as well as for β(1‐4) polyglucans having a degree of polymerization molecular weight averages (DPw) of 23, 37, 50, and 140 up to 3000. As a result we found that the activation energy (Ea) of the segmental chain motion has the lowest value (32 ± 1 kJ/mol) for cellobiose, followed by passing through a maximum for a DP between 7 and 15 with Ea = 51 ± 1 kJ/mol. Subsequently, the activation energy is decreased at a value around 44.8 ± 1.2 kJ/mol for chains containing more than 100 AGUs. Obviously, from a distinctly molecular dimension (DPw ∼ 100) the mean number of AGUs that take part in the local chain motions and cross‐correlation between the motions of neighboring AGUs are nearly the same and the chain length has no influence on the segmental motion. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2491–2500, 2001
Assessment of depression among cancer patients: the role of pain, cancer type and treatment
Authors: Ciaramella Antonella , Poli Paolo 
Published: August 2002

AbstractOne hundred consecutive cancer patients were assessed using two structured methods for assessing major depressive disorder—Structured Clinical Interview for DSM III‐R (SCID) and Endicott criteria—and using a depression rating scale—Hamilton Depression Rating Scale (HAMD).Forty‐nine percent of patients were depressed using SCID (DSM III‐R criteria), whereas 29% of patients were depressed using Endicott criteria. Twenty‐eight percent of patients were depressed using both criteria. Age and sex did not have any influence on the assessment of major depression. Both the structured interview and the rating scale were able to identify suicide ideation. Depressed patients were not shown to have more lifetime depression than non‐depressed patients using both structured methods. Patients who were depressed using both assessments of depression had more metastasis and pain than non‐depressed patients. Copyright © 2001 John Wiley & Sons, Ltd.
Employment patterns of long‐term cancer survivors
Authors: Bradley Cathy J. , Bednarek Heather L. 
Published: August 2002

AbstractAs more people are diagnosed at earlier stages and surviving cancer, they are increasingly likely to be at working ages, where issues regarding productivity and employment continuation must be addressed by patients and employers alike. To this end, we studied the employment patterns of 253 long‐term cancer survivors in the Detroit Metropolitan Area. Of those working at the time of their initial diagnosis, 67% were employed 5–7 years later. Patients who stopped working did so because they retired (54%), were in poor health/disabled (24%), quit (4%), cited other reasons (9%), or their business closed (9%). Many employed patients worked in excess of 40 h per week although some reported various degrees of disability that interfered with job performance. Overall, the ability of cancer patients to continue employment appears optimistic. Copyright © 2002 John Wiley & Sons, Ltd.
Lung development: Number of terminal bronchiolar duct endings and gas exchange surface area in victims of sudden infant death syndrome
Authors: Beech D.J. , Sibbons P.D. , Howard C.V. , van Velzen D. 
Published: August 2002

AbstractPrevious research has demonstrated impaired renal development, particularly with respect to glomerular number, in victims of sudden infant death syndrome (SIDS). The present study used stereological principles to estimate the volume of the upper lobe of the right lung, total number of terminal bronchiolar duct endings (TBDE), and gas exchange surface area of this lobe within a group of human infants. The infants were classified according to cause of death (SIDS or non‐SIDS), and further subdivided according to birth‐weight: normal birth‐weight (NBW) or low birth‐weight (LBW).The results demonstrated that TBDE density was significantly reduced in SIDS compared to non‐SIDS (P = 0.014), but only reduced from non‐SIDS NBW values in the SIDS NBW group (P  = 0.044). Total TBDE number was significantly reduced in SIDS from non‐SIDS (P = 0.001), and was significantly reduced from non‐SIDS NBW values in SIDS NBW (P  = 0.023). Mean gas exchange surface area per TBDE was significantly increased in SIDS compared to non‐SIDS cases (P = 0.049).The results of the present study indicate developmental delay of the lung in SIDS NBW infants who had previously not been considered growth retarded based on their normal body parameters. Pediatr Pulmonol. 2001; 31:339–343. © 2001 Wiley‐Liss, Inc.
Therapeutic equivalence of three metered‐dose inhalers containing salbutamol (Albuterol) in protecting against methacholine‐induced bronchoconstriction in children with asthma
Authors: Mallol Javier , Aguirre Viviana , Rhem Rodney , Rodriguez Jorge , Dolovich Myrna 
Published: August 2002

AbstractMany pharmaceutical companies sell salbutamol in metered‐dose inhalers (MDI) for the treatment of asthma. However, the therapeutic equivalence of the more recently released generic products has not been compared with the original patented product in children. Twenty children with mild to moderate asthma, presently asymptomatic and with normal lung function, were randomly allocated to receive 200 μg of inhaled salbutamol (Albuterol) from three MDIs prepared by different manufacturers: the original Glaxo product and two generic products. The three drug formulations and placebo were given 10 min before a methacholine challenge test to determine the degree of protection provided against methacholine‐induced bronchoconstriction (MIB) by each salbutamol aerosol. Tests were performed on 4 consecutive days. Doubling concentrations of methacholine were inhaled until the forced expired volume in 1 sec (FEV1) decreased by 20% from its baseline value.Compared to placebo, all patients increased significantly the provocation concentration that decreased FEV1 by 20% (PC20) by more than one doubling concentration after inhaling each of the three salbutamol aerosols. The effectiveness was not significantly different between medications (P = 0.8). There was a small but significant difference among MDIs in aerosol particle size and total and fine‐particle dose released per actuation. However, no relation was found between aerosol particle size or released dose and the protective effect.This study shows that the three tested brands of salbutamol MDI protected asthmatic children equally from MIB. When prescribing these salbutamol MDIs to prevent symptoms triggered by nonspecific stimuli in asthmatic children, the selection may be based on cost‐benefit criteria. Pediatr Pulmonol. 2001; 32:447–452. © 2001 Wiley‐Liss, Inc.
Prostate‐specific antigen and other prostate‐derived proteases cleave IGFBP‐3, but prostate cancer is not associated with proteolytically cleaved circulating IGFBP‐3
Authors: Koistinen Hannu , Paju Annukka , Koistinen Riitta , Finne Patrik , Lövgren Janita , Wu Ping , Seppälä Markku , Stenman Ulf‐Håkan 
Published: August 2002

AbstractBACKGROUNDProteolysis of insulin‐like growth factor‐binding proteins (IGFBPs) may increase IGF‐mediated growth stimulation and development of cancer in the organs producing large amounts of proteases, such as the prostate.METHODSWe studied proteolysis of IGFBP‐3 by three prostate‐derived proteases, namely prostate specific antigen (PSA), human kallikrein 2 (hK2), and trypsin, and also by native seminal plasma. Cleavage of 125I‐IGFBP‐3 was studied by SDS–PAGE and autoradiography. We also used two different sandwich‐type IGFBP‐3 immunoassays, called “intact” and “total” IGFBP‐3 assays. These assays differ in their capacity to recognize proteolytically degraded IGFBP‐3.RESULTSHK2, PSA, and trypsin all cleaved IGFBP‐3 at the concentrations normally present in seminal plasma. The IGFBP‐3 cleavage by seminal plasma was inhibited by ZnCl2, which strongly inhibits hK2 and PSA, but not by a specific trypsin inhibitor. The IGFBP‐3 fragments resulting from proteolytic cleavage by PSA, hK2, or trypsin were undetectable in the “intact IGFBP‐3 assay,” whereas the “total IGFBP‐3 assay” also detected the proteolytic fragments. No increased fragmentation of IGFBP‐3 was found in serum of 659 men with elevated PSA concentrations, of whom 178 had a proven prostate cancer. Furthermore, the IGFBP‐3 levels were not associated with the PSA concentrations.CONCLUSIONSThese results show that, while seminal plasma and prostate‐derived proteases can cleave IGFBP‐3, in patients with prostate cancer the circulating IGFBP‐3 is not significantly proteolyzed by either PSA, hK2, or trypsin. Prostate 50: 112–118, 2002. © 2002 Wiley‐Liss, Inc.
Endoglin (CD105) is expressed on immature blood vessels and is a marker for survival in prostate cancer
Authors: Wikström Pernilla , Lissbrant Ingela Franck , Stattin Pär , Egevad Lars , Bergh Anders 
Published: August 2002

AbstractBACKGROUNDEndoglin, a receptor for some of the members of the transforming growth factor‐β (TGF‐β) family, is expressed on proliferating endothelial cells and has been suggested as a marker of ongoing angiogenesis. In this study, endoglin was evaluated as a prognostic factor for prostate cancer progression.METHODSImmunohistochemical staining of endoglin was examined in 72 cases of prostate cancer and compared with immunohistochemical staining of the pan‐endothelial marker von Willebrand factor (vWf), clinicopathological factors, and cancer‐specific survival. Micro‐vessels were measured in the most vascularized fields. Double staining with antibodies against smooth muscle actin and endoglin or vWf, respectively, was performed in order to evaluate vessel maturation.RESULTSEndoglin‐stained tumor vessels were generally small and only 19% also stained with actin. Endoglin was a better prognostic marker than vWf. The median survival times were shorter for patients with tumor vascular count (vc) above median than for patients with vc below median (4 vs. 12 years, P = 0.0007, and 5 vs. 10 years, P = 0.018, for endoglin and vWf, respectively). Endoglin vc was associated with Gleason score (P = 0.001), local tumor stage (P = 0.0006), metastasis (P = 0.01), tumor cell immunoreactivity for TGF‐β1 (P = 0.0003), and tumor cell proliferation index (rs = 0.319, P = 0.02). Endoglin, in contrast to vWf, vc was prognostic for survival in the subgroup of patients with Gleason score 5, 6, and 7 tumors.CONCLUSIONSEndoglin marks principally small, probably newly formed tumor vessels in zthe prostate, and is a promising prognostic marker for prostate cancer patients. Prostate 51: 268–275, 2002. © 2002 Wiley‐Liss, Inc.
Identification of a plasma membrane Ca2+‐ATPase in epithelial cells and aposomes of the rat coagulating gland
Authors: Post Heidi , Wiche Regina , Sen Parimal C. , Hoffbauer Gudrun , Albrecht Martin , Seitz Jürgen , Aumüller Gerhard , Wilhelm Beate 
Published: August 2002

AbstractBACKGROUNDEpithelial cells of the rat coagulating gland secrete a minor fraction of proteins by means of an alternative export mode named apocrine secretion. Thereby, proteins are released by means of membrane bounded blebs or “aposomes” arising from the apical plasma membrane. Little is known about the composition of the aposomal membrane and whether or not proteins located in the apical plasma membrane are integrated into the aposomes.METHODSTo show expression and localization of Ca2+‐ATPase in rat coagulating gland, reverse transcriptase‐polymerase chain reaction, Western blotting experiments, and Ca2+‐ATPase activity assays, as well as immunofluorescence studies were performed.RESULTSCa2+‐ATPase is located in the apical plasma membrane of the epithelial cells of the rat coagulating gland and is also included in the aposomes. Mg2+‐dependent and Mg2+‐independent Ca2+‐ATPase activity was observed in coagulating gland primary epithelial cells and tissue. Gene expression of plasma membrane Ca2+‐ATPase isoforms 1 and 4 was detected in cultured primary epithelial cells of the rat coagulating gland and coagulating gland tissue.CONCLUSIONSWe show for the first time that Ca2+‐ATPase as an important, functionally active membrane protein of the apical plasma membrane is incorporated into the aposomal membranes and is released from the cells during apocrine secretion process. Prostate 52:159–166, 2002. © 2002 Wiley‐Liss, Inc.