bluuebunny/crossref_metadata_2025 huggingface dataset:
Finite element interface models for the delamination analysis of laminated composites: mechanical and computational issues
Authors: Alfano G. , Crisfield M. A.
Published: August 2002

The finite element analysis of delamination in laminated composites is addressed using interface elements and an interface damage law. The principles of linear elastic fracture mechanics are indirectly used by equating, in the case of single‐mode delamination, the area underneath the traction/relative displacement curve to the critical energy release rate of the mode under examination. For mixed‐mode delamination an interaction model is used which can fulfil various fracture criteria proposed in the literature. It is then shown that the model can be recast in the framework of a more general damage mechanics theory. Numerical results are presented for the analyses of a double cantilever beam specimen and for a problem involving multiple delamination for which comparisons are made with experimental results. Issues related with the numerical solution of the non‐linear problem of the delamination are discussed, such as the influence of the interface strength on the convergence properties and the final results, the optimal choice of the iterative matrix in the predictor and the number of integration points in the interface elements. Copyright © 2001 John Wiley & Sons, Ltd.
The Parkinsonian neurotoxin 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine on membrane currents and intrasynaptosomal calcium
Authors: Mohanakumar K P , Ray S Samanta , Büsselberg D
Published: August 2002

Effects of the neurotoxin, 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) and its metabolite, 1‐methyl‐4‐phenyl pyridinium (MPP+) were investigated on neuronal membrane currents and intrasynaptosomal calcium levels employing whole cell patch clamp and FURA‐2AM respectively. Membrane currents elicited by voltage ramps as well as voltage activated potassium‐currents were studied in the cultured rat dorsal root ganglia (DRG) neurons. These neurons contained 0.36 ± 0.04 pmol/mg of dopamine as detected employing HPLC‐electrochemistry. MPTP and MPP+ (1 μM) respectively caused significant increase (25 ± 4%) or inhibition (53 ± 10%) of the total membrane current. Potassium‐currents elicited by voltage jumps from –80 to 0 mV were significantly inhibited (68 ± 8%) by MPP+, but MPTP caused no effect. MPP+‐induced increase in the FURA‐2 fluorescence signal was insensitive to extrasynaptosomal calcium, indicated intrasynaptosomal mobilization by the neurotoxin. These results suggest involvement of ion channels in MPTP neurotoxicity, and imply its role in the etiopathology of Parkinson’s disease.
Life values before versus after a breast cancer diagnosis*
Authors: Lampic Claudia , Thurfjell Erik , Bergh Jonas , Carlsson Marianne , Sjödén Per‐Olow
Published: August 2002

The main aim of this study was to investigate whether women's life values change with a breast cancer diagnosis. In addition, associations between life values and anxiety/depression ratings were investigated. Life value changes were prospectively studied in 517 women recalled for further examination after attending mammographic screening, 38 of whom were diagnosed with primary breast cancer. Life values were assessed by a study‐specific version of a life value questionnaire, including ratings of the perceived attainment and importance of seven life value dimensions. Three months after being recalled, women diagnosed with primary breast cancer reported a reduction of the attainment and the importance of Health. In addition, these women reported changes in the perceived importance of Responsibility and Involvement. High levels of anxiety and depression in particular were associated with large discrepancies between attainment and importance for some life values. This suggests that changes in the perceived importance of some life values may constitute one part of women's psychological adaptation to a breast cancer diagnosis. © 2002 Wiley Periodicals, Inc. Res Nurs Health 25:89–98, 2002
The role of donors: how to combine sector programme support with devolution? A comment from a practitioner to James Wunsch: ‘decentralization, local governance and “recentralization” in Africa’
Authors: Nielsen Henrik A.
Published: August 2002

In commenting on ‘Decentralization, Local Governance and ‘Recentralization’ in Africa’ (Wunsch, 2001), this article concurs with the general thesis of Wunsch that the actual implementation as distinct from the rhetoric of decentralization in Africa has featured lingering central retention of power and resources and that genuine local control over important services and investments remains elusive. However, there is evidence that this is not invariably the case and that donors may have decisive roles to play in encouraging local assertiveness in the medium term in providing leverage for change through budget support and technical assistance to civic education, training local councillors, monitoring local government elections and encouraging local government associations to put to the test the national commitment to genuine local governance. These roles include helping to ensure the transparency of central transfers and, as in Uganda and Malawi for example, assisting with the development of intermediary fiscal mechanisms in this regard. Learning from such promising experiences will be vital in nurturing the longer term optimism heralded by Wunsch. Copyright © 2002 John Wiley & Sons, Ltd.
Enhanced rigidity of recycled polypropylene from packaging waste by compounding with talc and high‐ crystallinity polypropylene
Authors: Tall Stefan , Albertsson Ann‐Christine , Karlsson Sigbritt
Published: August 2002

Polypropylene (PP) constituted 30% of the collected material in a Swedish collection system for rigid plastic packaging waste. The PP fraction was however a complex mixture of grades with widely different properties. In order to enhance the rigidity of the recycled PP, modified grades were prepared by compounding with talc and/or a virgin high‐crystallinity PP grade. Adding 20–40% of high‐crystallinity PP enhanced the stiffness and yield strength without impairing the impact resistance. A composite material consisting of 20% of this grade, 20% talc and 60% recycled PP gave mechanical properties similar to those of a commercial talc‐filled PP compound used for demanding engineering applications. The present study demonstrates that recycled PP derived from post‐consumer packaging waste can also be made useful for demanding engineering applications. Copyright © 2001 John Wiley & Sons, Ltd.
Preparation and use of polymer‐supported chiral ruthenium complex catalyst
Authors: Gao Jing‐Xing , Yi Xiao Dong , Tang Chun‐Liang , Xu Pian‐Pian , Wan Hui‐Lin
Published: August 2002

The chiral diiminodiphosphine ligand, [(R,R)‐P2N2],­has been prepared by the condensation of o‐(diphenylphosphino)benzaldehyde and 1,2‐diaminocyclohexane. [(R,R)‐P2N2] was reduced with excess NaBH4 in refluxing ethanol to afford the corresponding diaminodiphosphine ligand [(R,R)‐P2(NH)2]. The interaction of [(R,R)‐P2(NH)2] with trans‐RuCl2(DMSO)4 gave the chiral ruthenium complex [(R,R)‐RuP2(NH)2] in 84% yield. The reaction of [(R,R)‐RuP2(NH)2] with poly‐(acrylic acid) using dicyclohexylcarbodiimine as the coupling agent, gave water soluble poly(acrylic acid salt)‐supported chiral ruthenium complex [PAA‐(R,R)‐RuP2(NH)2]. These chiral ligands and ruthenium complexes have been fully characterized by microanalysis and IR, NMR spectroscopic methods. The polymer‐bound ruthenium complex [PAA‐(R,R)‐RuP2(NH)2] as catalyst was used in asymmetric transfer hydrogenation of acetophenone in 2‐propanol, producing the 1‐phenylethanol in 95% yield and 96% ee. The catalyst was reused twice with some loss of activity and enantioselectivity. Copyright © 2001 John Wiley & Sons, Ltd.
Adverse drug reactions as a cause for admissions to a department of internal medicine
Authors: Mjörndal Tom , Boman Marit Danell , Hägg Staffan , Bäckström Martin , Wiholm Bengt‐Erik , Wahlin Anders , Dahlqvist Rune
Published: August 2002

Purpose

To assess the occurrence and pattern of adverse drug reactions as a cause for acute hospital admission.

Methods

In 681 randomly selected patients, acutely admitted to a clinic of internal medicine at a Swedish university hospital, information was collected from their medical records about current symptoms and use of drugs, previous diseases and the results of medical investigations and tests. In addition, a standardized interview according to a questionnaire was carried out. A group of experts in clinical pharmacology assessed the data obtained from the patients' case records and the results of the interviews, and then, according to WHO criteria, judged the probability that an adverse drug reaction could have caused or contributed to the actual admission to hospital.

Results

Out of the 681 cases included, 94 (13.8%) had symptoms and signs that were judged as drug‐related and that had caused or contributed to the admission. Eighty‐two patients (12.0%) had altogether 99 symptoms that were classified as adverse drug reactions. Of these, 91% were type A reactions. The relationship between the medication and the reaction was judged certain in eight, probable in 17, and possible in 74 cases. The most common adverse drug reactions were cardiovascular (36.3%). Twelve patients (1.8%) had symptoms indicating intoxications.

Conclusions

The prevalence of drug‐related problems causing or contributing to admission to a clinic of internal medicine is high and is dominated by type A reactions, i.e. reactions in principle predictable and preventable. This implies a possibility to increase drug safety by preventive measures. Copyright © 2002 John Wiley & Sons, Ltd.
Viscoelastic properties of branched polyacrylate melts
Authors: Ahmad Nasir M , Lovell Peter A , Underwood Sylvia M
Published: August 2002

The viscoelastic properties of poly(n‐butyl acrylate), poly(ethyl acrylate) and poly(methyl acrylate) melts have been studied using samples that varied in both molar mass and the mol% branched repeat units, these properties having been previously determined by gel permeation chromatography and 13C NMR spectroscopy, respectively. Poly(n‐butyl acrylate) was studied most extensively using seven samples; one sample of poly(n‐butyl acrylate), two samples of poly(ethyl acrylate) and one sample of poly(methyl acrylate) were used to study the effect of side‐group size. Storage and loss moduli were measured over a range of frequency (1 × 10−3 to 1 × 102 rad s−1) at temperatures from Tg + 20 °C to Tg + 155 °C and then shifted to form master curves at Tg + 74 °C through use of standard superposition procedures. The plateau regions were not distinct due to the broad molar mass distributions of the polyacrylates. Hence, the upper and lower limits of shear storage modulus from the nominal ‘plateau’ region of the curves for the seven poly(n‐butyl acrylate) samples were used to calculate the chain molar mass between entanglements, Me, which gave the range 13.0 kg mol−1 < Me < 65.0 kg mol−1. The Graessley–Edwards dimensionless interaction density and dimensionless contour length concentration were calculated for poly(n‐butyl acrylate) using the mean value of plateau modulus (1.2 × 105 Pa) and three different methods for estimation of the Kuhn length; the data fitted closely to the Graessley–Edwards universal plot. The Williams–Landel–Ferry C1 and C2 parameters were determined for each of the polyacrylates; the data for the poly(n‐butyl acrylate) samples indicate an overall reduction in C1 and C2 as the degree of branching increases. Although the values of C1 and C2 were different for poly(n‐butyl acrylate), poly(ethyl acrylate) and poly(methyl acrylate), there is no trend for variation with structure. Thus the viscoelastic properties of the polyacrylate melts are similar to those for other polymer melts and, for the samples investigated, the effect of molar mass appears to dominate the effect of branching.

© 2001 Society of Chemical Industry
An investigation of 1H and 13C longitudinal relaxation and relaxation in the rotating frame in solid poly(N‐vinylcarbazole)
Authors: Heatley Frank , Karali Aglaia , Dais Photis
Published: August 2002

1H and 13C longitudinal relaxation times (T1) and relaxation times in the rotating frame (T1ρ) have been measured for poly(N‐vinylcarbazole) in the solid state in air and nitrogen atmospheres in an attempt to elucidate molecular motions. In air, the T1 relaxation of both 1H and 13C was dominated by interaction with absorbed paramagnetic oxygen. In nitrogen, the 13C T1 relaxation times were long (>300 s) and were averaged by 13C–13C spin diffusion. The 13C T1ρ relaxation times showed an exponential dependence on the strength of the rotating 13C magnetic field and were thus controlled by spin–spin processes rather than spin–lattice processes.

© 2001 Society of Chemical Industry
Photo‐oxidative degradation in polyisoprene: surface characterization and analysis by atomic force microscopy
Authors: Blach Jolanta A , Watson Gregory S , Busfield W Ken , Myhra Sverre
Published: August 2002

Surface adhesion and surface mechanical properties of natural rubber cast films have been investigated by atomic force microscopy (AFM) before and after UV irradiation. Analysis in the force versus distance (F–d) mode probed changes in tip‐to‐surface adhesion. Adhesion was observed to increase as a result of exposure, in accord with the prediction that generation of polar groups in the surface should promote a hydrophilic transition. The hydrophilicity also gives rise to a stronger adhesive contribution from a meniscus force, as demonstrated by comparison of results obtained in air for irradiated and as‐received samples. Calculated values of work of adhesion, based on the Johnson–Kendall–Roberts model, reflected the changes in surface chemistry and the effects of the fluid environment. The outcomes of F–d analyses revealed both tip indentation and polymer extension; the former was fitted to expressions derived from the Snedden formalism, followed by calculation of an effective Young's modulus. Good agreement was obtained for as‐received surfaces with bulk measurements. The photochemistry predicts chain scission events which are likely to account for the observed softening of the polymer.

© 2001 Society of Chemical Industry
Preparation and properties of EPDM/organomontmorillonite hybrid nanocomposites
Authors: Chang Young‐Wook , Yang Yungchul , Ryu Seunghoon , Nah Changwoon
Published: August 2002

Hybrid nanocomposites based on organophillic montmorillonite (MMT) and ethylene–propylene–diene rubber (EPDM) have been prepared by a melt compounding process. From analysis by X‐ray diffraction and transmission electron microscopy, the rubber molecules were found to be intercalated into the galleries of organoMMT and the silicate layers of organoMMT are uniformly dispersed as platelets of 50–80 nm thickness in the EPDM matrix. Dynamic mechanical studies reveal a strong rubber–filler interaction in the hybrid nanocomposite which is manifested in the lowering of tan δ at the glass transition temperature. The hybrid nanocomposites exhibit great improvement in tensile and tear strength, and modulus, as well as elongation‐at‐break. Moreover, the permeability of oxygen for the hybrid nanocomposite was reduced remarkably.

© 2002 Society of Chemical Industry
Lambertian light trapping in textured solar cells and light‐emitting diodes: analytical solutions
Authors: Green Martin A.
Published: August 2002

Light trapping by texturing solar cell surfaces has produced significant gains in solar cell performance over recent decades, particularly for cells based on the relatively weakly absorbing semiconductors, such as crystalline silicon and amorphous silicon–hydrogen alloys. Previous solutions for the properties of the resulting textured optical sheets have been based on approximations valid in the weak absorption limit or have been obtained numerically. Analytical solutions are described for ideal Lambertian light trapping and these results used to deduce simple solutions that apply in other than the weak absorption limit. Copyright © 2002 John Wiley & Sons, Ltd.
Cross‐survey analysis of school violence and disorder
Authors: Coggeshall Mark B. , Kingery Paul M.
Published: August 2002

School psychologists and administrators are often asked to respond to student violence and disorder based on incomplete or inaccurate information about the nature and scope of these problems in their schools. Records of disciplinary actions and incidents may reflect only the tip of the proverbial iceberg. In national surveys, school administrators report rates of violence and disorder that are only a small fraction of the rates reported by students in national self‐report surveys. Student self‐report surveys on school violence and disorder may offer school officials a means of more accurately appraising the prevention needs of their students. This article compares the methods and findings of three national surveys of students in an effort to understand what methodological characteristics have the most salient impact on their findings. The article examines measures of school‐related weapon carrying and fear from all three national surveys contrasting their modes of administration and question phrasing. Estimates from even the most expertly designed and administered survey will include some error. However, the stability and comparability of the national surveys across time and across surveys suggest that student self‐report surveys are valuable tools for school‐level needs assessment. © 2001 John Wiley & Sons, Inc.
Legal implications of profiling students for violence
Authors: Bailey Kirk A.
Published: August 2002

Predicting violent activity with a youth violence profile in schools raises a host of legal concerns focusing on the validity and use of profiles as social science evidence: the impact of potential discrimination, search and seizure, and the implications for privacy. Schools differ from airports or other settings where profiles are used. Profiles are useful if they properly establish reasonable suspicion to stop an individual. They raise more problematic constitutional issues when they support referring a student to alternative educational services. Where a profile identifies students based on race, gender, or proxies for these characteristics, it is invalid. It can also be invalid if it is not a reasonable method of achieving the government's interest in safe schools. In addition, profiles present significant problems for confidentiality. These issues rest on fundamental concerns about the general validity of profiles as scientific tools: their objectivity, accuracy, sensitivity, overinclusiveness, and general scientific acceptance. Consequently, the use of profiles in a school setting is highly problematic and controversial. © 2001 John Wiley & Sons, Inc.
Neighboring group participation in the gas phase. The homogeneous elimination kinetics of 5‐(N‐phenylamino)‐1‐pentyl acetate and 5‐(N‐methyl‐N‐phenylamino)‐1‐pentyl acetate
Authors: Chuchani Gabriel , Al‐Awadi Nouria , Domínguez Rosa M. , Kaul Kamini
Published: August 2002

The elimination kinetics of the title compounds were determined over the temperature range 370–420 °C and pressure range of 36–91 Torr (1 Torr = 133.3 Pa). The reactions carried out in seasoned vessels with the free radical suppressor toluene always present are homogeneous, unimolecular and obey a first‐order rate law. The overall rate coefficient is expressed by the following Arrhenius equations: for 5‐(N‐phenylamino)‐1‐pentyl acetate, log k1 (s−1) = (13.56 ± 0.19) − (211.8 ± 2.2) kJ mol−1 (2.303RT)−1 and for 5‐(N‐methyl‐N‐phenylamino)‐1‐pentyl acetate, log k1 (s−1) = (12.29 ± 0.41) − (182.9 ± 5.2) kJ mol−1 (2.303RT)−1. The formation of N‐phenylpiperidine in both reactions suggests the anchimeric assistance of the PhNH and Ph(CH3)N groups for a backside displacement. An intimate ion‐pair type of mechanism is assumed in the pyrolytic elimination of these phenylaminoalkyl acetates. Copyright © 2001 John Wiley & Sons, Ltd.
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

The 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

Two 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

Two 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

Organic 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

Structural 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

The 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

The 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

For 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

One 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

As 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

Previous 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

Many 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

BACKGROUND

Proteolysis 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.

METHODS

We 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.

RESULTS

HK2, 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.

CONCLUSIONS

These 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

BACKGROUND

Endoglin, 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.

METHODS

Immunohistochemical 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.

RESULTS

Endoglin‐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.

CONCLUSIONS

Endoglin 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

BACKGROUND

Epithelial 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.

METHODS

To 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.

RESULTS

Ca2+‐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.

CONCLUSIONS

We 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.
A multicenter clinical trial on the use of alpha1‐antichymotrypsin‐prostate‐specific antigen in prostate cancer diagnosis
Authors: Lein Michael , Jung Klaus , Hammerer Peter , Graefen Markus , Semjonow Axel , Stieber Petra , Ossendorf Manfred , Luboldt Hans‐Joachim , Brux Brigitte , Stephan Carsten , Schnorr Dietmar , Loening Stefan A.
Published: August 2002

BACKGROUND

The aim was to evaluate the clinical performance of alpha1‐antichymotrypsin prostate‐specific antigen (PSA‐ACT) for early diagnosis of prostate cancer (PCa) in a multicenter trial.

METHODS

Three hundred sixty‐seven white men with PCa and 290 with benign prostatic hyperplasia (BPH) with tPSA concentrations between 2 and 20 μg/L were analyzed. The Elecsys system 2010 (Roche Diagnostics, Germany) was used for determination of total PSA (tPSA) and free PSA (fPSA). The PSA‐ACT test was a prototype assay used on the ES system (Roche Diagnostics).

RESULTS

The median concentrations of tPSA (PCa: 8.43 μg/L vs. BPH: 6.60 μg/L) and PSA‐ACT (8.30 μg/L vs. 6.46 μg/L) were significantly different, respectively. The median ratios of fPSA/tPSA (PCa: 12% vs. BPH: 16%) and PSA‐ACT/tPSA (98% vs. 95%) were significantly different. Receiver operating characteristics (ROC) analysis for discrimination between PCa and BPH (tPSA between 2 and 20 μg/L) was performed with 252 matched pairs and showed that the area under the curve (AUC) of the ratio fPSA/tPSA (0.66) was significantly different from tPSA (0.50) and PSA‐ACT (0.52). PSA‐ACT alone or the ratio PSA‐ACT/tPSA (0.56) were not significantly different from tPSA. For tPSA between 4 and 10 μg/L (n = 145 pairs), the AUC of the ratio fPSA/tPSA (0.65) was significantly higher than tPSA (0.50) and PSA‐ACT (0.54). Significant differences between tPSA and PSA‐ACT or PSA‐ACT/tPSA (0.56) were not found.

CONCLUSIONS

The determination of PSA‐ACT as well as the PSA‐ACT/tPSA ratio did not improve the diagnostic impact in patients undergoing evaluation for PCa compared to fPSA/tPSA ratio. Prostate 47:77–84, 2001. © 2001 Wiley‐Liss, Inc.
Assembly of a tetrameric α‐helical bundle: Computer simulations on an intermediate‐resolution protein model
Authors: Smith Anne Voegler , Hall Carol K.
Published: August 2002

Discontinuous molecular dynamics (DMD) simulation on an intermediate‐resolution protein model is used to study the folding of an isolated, small model peptide to an amphipathic α‐helix and the assembly of four of these model peptides into a four‐helix bundle. A total of 129 simulations were performed on the isolated peptide, and 50 simulations were performed on the four‐peptide system. Simulations efficiently sample conformational space allowing complete folding trajectories from random initial configurations to be observed within 15 min for the one‐peptide system and within 15 h for the four‐peptide system on a 500‐MHz workstation. The native structures of both the α‐helix and the four‐helix bundle are consistent with experimental characterization studies and with results from previous simulations on these model peptides. In both the one‐ and four‐peptide systems, the native state is achieved during simulations within an optimal temperature range, a phenomenon also observed experimentally. The ease with which our simulations yield reasonable estimates of folded structures demonstrates the power of the intermediate‐resolution model developed for this work and the DMD algorithm and suggests that simulations of very long times and of multiprotein systems may be possible with this model. Proteins 2001;44:376–391. © 2001 Wiley‐Liss, Inc.
Risk posed to honeybees (Apis mellifera L, Hymenoptera) by an imidacloprid seed dressing of sunflowers
Authors: Schmuck Richard , Schöning Ralf , Stork Andreas , Schramel Oliver
Published: August 2002

In a greenhouse metabolism study, sunflowers were seed‐treated with radiolabelled imidacloprid in a 700 g kg−1 WS formulation (Gaucho® WS 70) at 0.7 mg AI per seed, and the nature of the resulting residues in nectar and pollen was determined. Only the parent compound and no metabolites were detected in nectar and pollen of these seed‐treated sunflower plants (limit of detection <0.001 mg kg−1). In standard LD50 laboratory tests, imidacloprid showed high oral toxicity to honeybees (Apis mellifera), with LD50 values between 3.7 and 40.9 ng per bee, corresponding to a lethal food concentration between 0.14 and 1.57 mg kg−1. The residue level of imidacloprid in nectar and pollen of seed‐treated sunflower plants in the field was negligible. Under field‐growing conditions no residues were detected (limit of detection: 0.0015 mg kg−1) in either nectar or pollen. There were also no detectable residues in nectar and pollen of sunflowers planted as a succeeding crop in soils which previously had been cropped with imidacloprid seed‐treated plants.

Chronic feeding experiments with sunflower honey fortified with 0.002, 0.005, 0.010 and 0.020 mg kg−1 imidacloprid were conducted to assess potential long‐term adverse effects on honeybee colonies. Testing end‐points in this 39‐day feeding study were mortality, feeding activity, wax/comb production, breeding performance and colony vitality. Even at the highest test concentration, imidacloprid showed no adverse effects on the development of the exposed bee colonies. This no‐adverse‐effect concentration of 0.020 mg kg−1 compares with a field residue level of less than 0.0015 mg kg−1 ( =  limit of detection in the field residue studies) which clearly shows that a sunflower seed dressing with imidacloprid poses no risk to honeybees. This conclusion is confirmed by observations made in more than 10 field studies and several tunnel tests.

© 2001 Society of Chemical Industry