bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis, characterization and conformational transitions in copolymers of 2‐(o‐chlorophenyl)‐4‐methylene‐1,3‐dioxolane with vinyl monomers
Authors: Morariu Simona , Bercea Maria 
Published: June 2004

AbstractCopolymers of 2‐(o‐chlorophenyl)‐4‐methylene‐1,3‐dioxolane with methyl methacrylate and styrene were synthesized in benzene at 85 °C in the presence of 2,2′‐azobisisobutyronitrile as initiator. The structure of the resulting copolymers was investigated and a polymerization mechanism was proposed. The intrinsic viscosity of the copolymers in dilute solutions of carbon tetrachloride was determined as a function of temperature and conformational transitions were investigated. Copyright © 2004 Society of Chemical Industry
Study of crystallization and melting behavior of polypropylene‐block‐polyethylenes copolymers fractionated from polypropylene and polyethylene mixtures
Authors: Xu Jun‐Ting , Ding Ping‐Jing , Fu Zhi‐Sheng , Fan Zhi‐Qiang 
Published: June 2004

AbstractA series of ethylene–propylene block copolymer fractions of differing compositions, while still retaining broad molecular weight distributions, were obtained by fractionation of polypropylene (PP) and polyethylene (PE) copolymers prepared by sequential polymerization of ethylene and propylene. The crystallization and melting behavior of the polypropylene‐block‐polyethylene fractions were studied. It was observed that the major component could suppress crystallization of the minor component, leading to a decrease in crystallinity and melting temperature. Non‐isothermal crystallization showed that crystallization of the ethylene block was less influenced by composition and cooling rate than the propylene block. At fast cooling rates, the ethylene block could crystallize prior to the propylene block. Isothermal crystallization kinetics experiments were also conducted. We found that the block copolymers with minor ethylene components had smaller Avrami exponents (n ≈ 1.0), hence indicating a reduced growth dimension of the PE crystals by the pre‐existing PP crystals. On the other hand, the ethylene block exhibited much larger Avrami exponents in those block copolymers with major ethylene contents. Copyright © 2004 Society of Chemical Industry
A relaxational and conductive study on two poly(ether imide)s
Authors: Sanchis MJ , Díaz–Calleja R , Jaïmes C , Belana J , Cañadas JC , Diego JA , Mudarra M , Sellarès J 
Published: June 2004

AbstractA study of the relaxations and the conductivity of poly(ether imide) (PEI) ULTEM 5000 was carried out. The results were compared with the ones obtained in a previous study of PEI ULTEM 1000. The glass transition temperature was determined by differential scanning calorimetry (DSC). Then, the relaxations of PEI ULTEM 5000 using the thermally stimulated depolarization current technique (TSDC) on conventionally polarized electrets were studied. Owing to the interesting structure indicated by this technique a more detailed analysis of the β relaxation was done using window polarization (WP). It was possible to isolate 7 subrelaxations that we related to their counterparts in PEI ULTEM 1000. WP was also used to compare, one by one, the other relaxations that both materials present. The analysis of the ρ relaxation showed that the space trapping capability is stronger in PEI ULTEM 5000. The role of conductivity was analyzed using open circuit polarized samples and, more quantitatively, using dielectric analysis (DEA) and the dielectric modulus formalism. DEA and dynamic mechanical thermal analysis (DMTA) were also used to obtain information about the polar relaxations, complementary to that obtained by TSDC. Copyright © 2004 Society of Chemical Industry
Synthesis of narrow‐polydispersity degradable dendronized aliphatic polyesters
Authors: Lee Cameron C. , Grayson Scott M. , Fréchet Jean M. J. 
Published: June 2004

AbstractThe divergent dendronization of an ϵ‐caprolactone‐based polymer has been performed to provide access to dendronized polymers with sufficient biocompatibility and degradability for use as drug‐delivery scaffolds. The synthesis was performed through the tin(II) 2‐ethylhexanoate‐catalyzed polymerization of a γ‐functionalized ϵ‐caprolactone monomer, followed by the divergent growth of pendant polyester dendrons at each repeat unit. The resulting dendronized polymers were obtained up to the fourth generation with molecular weights as high as 80,000 Da and with polydispersities between 1.11 and 1.22. The fourth‐generation hydroxyl‐terminated dendronized polymer was degradable under a variety of aqueous conditions. A comparison of the dendronization approach with a procedure involving the ring‐opening polymerization of a second‐generation dendritic macromonomer reveals that the former procedure is best suited for the preparation of this family of dendronized polyesters because it requires shorter reaction times and affords materials with higher degrees of polymerization. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3563–3578, 2004
Heterochain model for simultaneous long‐chain branching and crosslinking. II. Application to free‐radical polymerization
Authors: Tobita Hidetaka 
Published: June 2004

AbstractThe matrix formula developed in the context of hetrochain theory, M̄w = M̄wp + WF(I − M)−1S, was applied to describe the molecular weight development during free‐radical homopolymerization. All of the required probabilistic parameters are expressed in terms of the kinetic‐rate constants and various concentrations. In free‐radical polymerization, the primary chains are formed consecutively, and the number of heterochain types, N, is extrapolated to infinity. Practically, such extrapolation can be conducted on the basis of the calculated values for only three different N values with sufficient accuracy. This matrix formula is valid regardless of the chemical and reactor systems used, as long as the primary chain‐connection statistics is considered Markovian. The gel point can be determined simply by solving an equation det(I − M) = 0. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2791–2800, 2004
Heterochain model for simultaneous long‐chain branching and crosslinking. III. Multicomponent polymerization
Authors: Tobita Hidetaka 
Published: June 2004

AbstractThe matrix formula developed in the context of heterochain theory, M̄w = M̄wp + WF(I − M)−1S, was applied to describe the molecular weight development during free‐radical multicomponent polymerization. All of the required probabilistic parameters are expressed in terms of the kinetic‐rate constants and the various concentrations associated with them. In free‐radical polymerization, the number of heterochain types, N, needs to be extrapolated to infinity, and such extrapolation is conducted with only three different N values. This matrix formula can be used as a benchmark test if other approximate approaches can give reasonable estimates of the weight‐average molecular weights. The moment equations with the average pseudo‐kinetic‐rate constants for branching and crosslinking reactions may provide poor estimates when the copolymer composition drift during polymerization is very significant. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2801–2812, 2004
Toxicity of the entomopathogenic fungus, Metarhizium anisopliae (Deuteromycotina: Hyphomycetes) to adult females of the blowfly Lucilia sericata (Diptera: Calliphoridae)
Authors: Wright C , Brooks A , Wall R 
Published: June 2004

AbstractThe fungus Metarhizium anisopliae (Metchnikoff) (Deuteromycotina: Hyphomycetes) is a natural component of soil flora world‐wide and is a causal agent of the green muscardine diseases of insects. The use of this pathogen as a potential biocontrol agent against adult females of the blowfly, Lucilia sericata (Meigen) (Diptera: Calliphoridae) was considered. The blowfly L sericata is an economically important agent of cutaneous myiasis of sheep, particularly in northern Europe. Exposure of flies to suspensions of fungal spores by immersion, topical application or tarsal contact with treated surfaces all resulted in high levels of fatal infection. Spores suspended in silicone oil resulted in higher levels of infection (50–70%) than those formulated in a 0.3 g litre−1 solution of the detergent Tween 80 (10–20%). Spore concentration had a significant effect on levels of infection of flies, with the highest levels of mortality (64%) resulting from a suspension of 1 × 107 conidia ml−1. The duration of tarsal contact had a significant effect on levels of infection. Mean infection levels of 30% were observed following exposure of free‐flying adults to a single spore‐treated, 5 × 15 cm2 cloth surface suspended from the roof of a cage (30 cm cube). The implications of the results for the potential use of M anisopliae in the biocontrol of blowflies are discussed. Copyright © 2004 Society of Chemical Industry
Determination of aldicarb, carbofuran and some of their main metabolites in groundwater by application of micellar electrokinetic capillary chromatography with diode‐array detection and solid‐phase extraction
Authors: Arráez‐Román David , Segura‐Carretero Antonio , Cruces‐Blanco Carmen , Fernández‐Gutiérrez Alberto 
Published: June 2004

AbstractThis paper describes a UV detection method for the pesticides aldicarb and carbofuran, and some of their main metabolites, aldicarb‐sulfoxide, aldicarb‐sulfone and 3‐hydroxy‐carbofuran, in ground waters. Micellar electrokinetic chromatography (MEKC) with diode‐array detection was developed for their determination at 210 nm. The experimental study was performed using sodium dodecyl sulfate (SDS) at a concentration level of 140 mM, and a buffer of borax/HCl 20 mM at pH 8 which gives the best resolution with an analysis time of less than 20 min. Different instrumental parameters such as voltage (23 kV), injection time (12 s) and temperature (25 °C) were optimized. The detection limits were in the range 2–7.4 µg litre−1 by solid‐phase extraction (SPE) with a subsequent evaporation step. Groundwater spiked samples were pre‐concentrated off‐line with graphite carbon and subsequently analyzed by MEKC with diode‐array detection yielding average recoveries between 77 and 97% (n = 4) with RSD between 2–7%. Copyright © 2004 Society of Chemical Industry
Novel features of amphiphilic peptide Mas7 in signalling via heterotrimeric G‐proteins
Authors: Bavec Aljoša 
Published: June 2004

AbstractAmphiphilic peptide Mas7, a structural analogue of mastoparan is a known activator of heterotrimeric Gi‐proteins and its downstream effectors. This study investigated the functional interaction of Mas7 with a plasma membrane protein from CHO cells, the endogenous mono‐ADP‐ribosyltransferase. The substrate of endogenous mono‐ADP‐ribosyltransferase was the ADP‐ribosylated protein with a molecular mass of 36 kDa, which corresponded to the β subunit of heterotrimeric G‐proteins. The effect of Mas7 on endogenous mono‐ADP‐ribosyltransferase activity was in the micromolar range with a maximal activation of 205% over the basal. In pertussis treated plasma membranes, it was found that the effect of Mas7 on endogenous mono‐ADP‐ribosyltransferase was partially blocked, which suggests the involvement of G‐proteins, such as Gi or G0. In addition, an immunoassay was developed for the visualization of interaction between the α subunit and the βγ dimer of G‐protein on a Ni‐NTA support. The physical interaction was tested of Mas7 with the heterotrimeric G‐protein αi2 subunit, which was overexpressed together with β1γ2–His6 subunits in sf9 cells. An interaction between Gi2 heterotrimer and Mas7 was not observed, which was not in accordance with previously reported results of mastoparan obtained for Gi‐proteins from bovine brain. In conclusion, the signal is mediated from Mas7 to endogenous mono‐ADP‐ribosyltransferase via pertussis sensitive G‐proteins. Furthermore, it is hypothesized that Gi2 G‐proteins are not involved in the process. Copyright © 2004 European Peptide Society and John Wiley & Sons, Ltd.
A Note on Weighted Least‐squares Estimation of the Shape Parameter of the Weibull Distribution
Authors: Lu Hai‐Lin , Chen Chong‐Hong , Wu Jong‐Wuu 
Published: June 2004

AbstractThis study proposes an alternative to the weighted least‐squares (WLS) procedure for estimating the shape parameter of the Weibull distribution. Bergman (Journal of Materials Science Letters 1986; 5:611–614), Faucher and Tyson (F&T) (Journal of Materials Science Letters 1988; 7:1199–1203) suggested using different WLS approaches for Weibull parameters. However, the simulation results show that the novel approach is better than that of Bergman, and is not significantly different from that of F&T. Furthermore, the novel approach is also simpler and easier to comprehend. Copyright © 2004 John Wiley & Sons, Ltd.
Refined Rank Regression Method with Censors
Authors: Wang Wendai 
Published: June 2004

AbstractReliability engineers often face failure data with suspensions. The rank regression method with an approach introduced by Johnson has been commonly used to handle data with suspensions in engineering practice and commercial software. However, the Johnson method makes partial use of suspension information only—the positions of suspensions, not the exact times to suspensions. A new approach for rank regression with censored data is proposed in this paper, which makes full use of suspension information. Taking advantage of the parametric approach, the refined rank regression obtains the ‘exact’ mean order number for each failure point in the sample. With the ‘exact’ mean order number, the proposed method gives the ‘best’ fit to sample data for an assumed times‐to‐failure distribution. This refined rank regression is simple to implement and appears to have good statistical and convergence properties. An example is provided to illustrate the proposed method. Copyright © 2004 John Wiley & Sons, Ltd.
Derivation of a general formula for the Shibuya–Wulfman matrix
Authors: Red Eddie , Weatherford Charles A. 
Published: June 2004

AbstractAn explicit and general formula for the Shibuya–Wulfman matrix, which may easily be programmed, is derived. The derivation closely follows the Fourier transform methods of Weniger. A graph of a number of typical matrix elements is given to show the dependence of the Shibuya–Wulfman matrix on the translation distance multiplied by the screening parameter. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
On the computation of (2‐2) three‐center Slater‐type orbital integrals of 1/r12 using Fourier‐transform‐based analytical formulas
Authors: Antolovic Danko , Silverstone Harris J. 
Published: June 2004

AbstractWe describe a computational scheme devised for using Fourier‐transform‐based analytic formulas for three‐center integrals of r, wherein each electron is described by a two‐center product of Slater‐type orbitals. The asymptotic behavior of the auxiliary functions, which are related to modified spherical Bessel functions and to exponential integrals, is investigated, and recursive computational schemes are derived that are shown to be numerically stable for high summation indices and large internuclear distances. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Fast and stable algorithm for analytical evaluation of two‐center overlap integrals over Slater‐type orbitals with integer and noninteger principal quantum numbers
Authors: Özdoğan Telhat 
Published: June 2004

AbstractA unified algorithm is presented for analytical evaluation of two‐center overlap integrals over Slater‐type orbitals with integer and noninteger principal quantum numbers. Two‐center overlap integrals are expressed as finite sum of Gaunt coefficients and auxiliary functions S(p, t). Special attention is paid to the efficient calculation of this auxiliary function by introducing analytic and recurrence relations. In order to test the accuracy of the formula for two‐center overlap integrals, we performed an extensive study in which quantum numbers, orbital exponents, and internuclear distances were varied over wide ranges. We found that the method presented here for two‐center overlap integrals is fully reliable for very high quantum numbers and the computation times are very low. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Children and work‐related stress among physicians
Authors: Töyry Saara , Kalimo Raija , Äärimaa Markku , Juntunen Juhani , Seuri Markku , Räsänen Kimmo 
Published: June 2004

AbstractThe aim of this study was to analyse the influence of gender and children on physicians' stress and burnout and to obtain information on the compromises physicians make between family and work. The study was based on a nationwide survey of 3313 Finnish physicians. The results showed that work was the commonest reason for stress for both male and female physicians. If physicians had children, combining work and family was the commonest reason for stress among the women, but work still remained the commonest reason for stress among the men. The female physicians had made compromises between family and work more often than the male physicians (limited the number of children, delayed having children, given up postgraduate or continuing medical education, worked part‐time because of family, and given up a job because of a spouse's need to move). The female physicians—with or without children—were more likely than the male physicians to experience severe or moderate exhaustion and less likely than the male physicians to experience cynicism as components of burnout. Among both genders of physicians, having children was associated with less cynicism and reduced personal accomplishment, but the children did not affect exhaustion. In conclusion, having children is associated with a lower level of some burnout symptoms. Additional studies are needed to explain the health effects of work–family balance for physicians. Copyright © 2004 John Wiley & Sons, Ltd.
The effects of a mindfulness‐based stress reduction program on stress, mindfulness self‐efficacy, and positive states of mind
Authors: Chang Vickie Y. , Palesh Oxana , Caldwell Rebecca , Glasgow Nathan , Abramson Mark , Luskin Frederic , Gill Michelle , Burke Adam , Koopman Cheryl 
Published: June 2004

AbstractMindfulness‐based stress reduction (MBSR) has grown in popularity over the last two decades, showing efficacy for a variety of health issues. In the current study, we examined the effects of an MBSR intervention on pain, positive states of mind, stress, and mindfulness self‐efficacy. These measures were collected before and following an 8‐week intervention. Post‐intervention levels of stress were significantly lower than pre‐intervention levels, while mindfulness self‐efficacy and positive states of mind were at significantly higher levels. The findings underscore the potential for stress management, awareness and attention training, and positive states of mind using MBSR. Copyright © 2004 John Wiley & Sons, Ltd.
The significance of urethral hyperechogenicity in female lower urinary tract symptoms
Authors: Yang J.‐M. , Huang W.‐C. 
Published: June 2004

AbstractObjectiveTo explore the significance of hyperechogenic spots in the urethra on ultrasound cystourethrography.MethodsOne hundred and five women with lower urinary tract symptoms who had undergone urodynamic study and ultrasound cystourethrography were included. Ultrasound cystourethrography was used to evaluate the morphology of the lower urinary tract, including the bladder neck position, bladder wall thickness at the trigone and dome, and presence or absence of hyperechogenic spots (urethral hyperechogenicity) in the urethra and their location and number.ResultsOf the 105 women, 30 (29%) had hyperechogenic spots in the urethra, including 26 (87%) with only one spot; 17 (53%) of the echogenic spots were located in the proximal urethra, including four cases with multiple echogenic spots. No significant differences were found in the demographics, urinary symptoms, ultrasonographic, urodynamic and urethrocystoscopic findings between those women with and without urethral hyperechogenicity, except for parity (P = 0.030). There was no association between urethral hyperechogenicity and urinary symptoms. A weak but negative correlation between the number of echogenic spots in the urethra and maximum urethral pressure was found in the subgroup with urethral hyperechogenicity (r = −0.421; P = 0.023).ConclusionOn ultrasound cystourethrography, a single echogenic spot in the urethra is not associated with specific urinary symptoms and does not affect urethral function. Copyright © 2004 ISUOG. Published by John Wiley & Sons, Ltd.
Multicenter randomized trial of a comprehensive hospital discharge and outpatient heart failure management program
Authors: Atienza Felipe , Anguita Manuel , Martinez‐Alzamora Nieves , Osca Joaquín , Ojeda Soledad , Almenar Luis , Ridocci Francisco , Vallés Federico , de Velasco José A. 
Published: June 2004

AbstractAims:Disease management programs can reduce hospitalizations in high‐risk heart failure (HF) patients, but generalizability to the population hospitalized for HF remains to be proven. We aimed to assess the effectiveness of a discharge and outpatient management program in a non‐selected cohort of patients hospitalized for HF.Methods and results:Patients admitted with decompensated HF were randomized to receive usual care (n=174) or an intervention (n=164) consisting of a comprehensive hospital discharge planning and close follow‐up at a HF clinic. After a median of 509 days, there were fewer events (readmission or death) in the intervention as compared with the control group (156 vs. 250), which represents 47% (95%CI: 29–65; P<0.001) event reduction per observation year. At 1‐year, time to first event, time to first all‐cause and HF readmission, and time to death were increased in the intervention group (P<0.001). All‐cause and HF readmission rates per observation year were significantly lower, quality of life improved and overall cost of care was reduced in the intervention group.Conclusions:This comprehensive hospital discharge and outpatient management program prolonged time to first event, reduced hospital readmissions, improved survival and quality of life of patients hospitalized for HF, while reducing cost of management.
Regulation of caspase 3 and Fas in pressure overload‐induced left ventricular dysfunction
Authors: Philipp Sebastian , Pagel Ines , Höhnel Klaus , Lutz Jens , Buttgereit Jens , Langenickel Thomas , Hamet Pavel , Dietz Rainer , Willenbrock Roland 
Published: June 2004

AbstractBackground:The presence of apoptotic cell death in cardiac myocytes is now well established and the contribution of apoptosis for the development of heart failure has been suggested. However, the mechanism responsible for the induction of apoptosis remains unclear. The present study was designed to investigate the involvement of Fas and caspase 3 in the transition from pressure overload‐induced left ventricular hypertrophy (LVH) to left ventricular dysfunction (LVD).Methods:Pressure overload induced LVH (10 days) and LVD (30 days) were induced by thoracic aortic banding. Changes in apoptosis‐related genes were studied in rats with thoracic aortic banding. After 10 and 30 days, cardiac Fas mRNA expression was measured by RT‐PCR. The mRNA expression of caspase 3 was detected by RNase protection assay. The activity of caspase 3 was measured by fluorometric assay. Protein levels of caspase 3 were measured by Western blot.Results:Rats with aortic banding had increased heart/body weight ratios after 10 and 30 days, compared to controls. Central venous pressure and lung weights were increased, left ventricular contractility was significantly impaired only in rats after 30 days of aortic banding, indicating LVD. Caspase 3 mRNA expression (7.1±0.1 vs. 2.8±0.4, P<0.05), caspase 3 activity (1418±181 vs. 849±154 AU, P<0.05) as well as caspase 3 protein levels were increased in rats with LVD but not with LVH. Similarly, Fas mRNA was increased in rats with LVD.Conclusions:The activation of Fas and caspase 3 only after 30 days of aortic banding suggests that induction of these pathways may be involved in pressure overload‐induced LVD.