bluuebunny/crossref_metadata_2025 huggingface dataset:
Regional variability in Mackenzie Inuit beluga whale use
Authors: Friesen T. Max , Morrison David
Published: August 2002

Inuit of the Mackenzie Delta region, Northwest Territories, relied on a wide range of subsistence resources, however they are best known as the consummate hunters of beluga whales (Delphinapterus leucas). This species represented a focal resource for the two regional groups centred on the East Channel of the Mackenzie River, but was available much less frequently and reliably to adjacent groups, who relied to a greater degree on alternative resources such as caribou, fish, seals, and bowhead whales. In this paper, we compare archaeofaunas from sites located in the “core” beluga whaling zone of the Mackenzie River East Channel with other sites to the east and west for which direct access to beluga whales was either reduced or non‐existent. Bone frequencies are compared both in terms of proportional species representation in site archaeofaunas, and in terms of differential element representation. These comparisons are then interpreted within a framework emphasizing regional economic patterns, as well as local variability in patterns of beluga acquisition, storage, transport, and disposal. Copyright © 2002 John Wiley & Sons, Ltd.
Optimal control of innate immune response
Authors: Stengel Robert F. , Ghigliazza Raffaele , Kulkarni Nilesh , Laplace Olivier
Published: August 2002

Treatment of a pathogenic disease process is interpreted as the optimal control of a dynamic system. Evolution of the disease is characterized by a non‐linear, fourth‐order ordinary differential equation that describes concentrations of pathogens, plasma cells, and antibodies, as well as a numerical indication of patient health. Without control, the dynamic model evidences sub‐clinical or clinical decay, chronic stabilization, or unrestrained lethal growth of the pathogen, depending on the initial conditions for the infection. The dynamic equations are controlled by therapeutic agents that affect the rate of change of system variables. Control histories that minimize a quadratic cost function are generated by numerical optimization over a fixed time interval, given otherwise lethal initial conditions. Tradeoffs between cost function weighting of pathogens, organ health, and use of therapeutics are evaluated. Optimal control solutions that defeat the pathogen and preserve organ health are demonstrated for four different approaches to therapy. It is shown that control theory can point the way toward new protocols for treatment and remediation of human diseases. Copyright © 2002 John Wiley & Sons, Ltd.
Does choice lead to racially distinctive schools? Charter schools and household preferences
Authors: Weiher Gregory R. , Tedin Kent L.
Published: August 2002

A persistent fear regarding school choice is that it will lead to more racially distinctive schools. A
growing number of studies compares choosing households to non‐choosing households, but few have examined
the possibility that choosers sort themselves out based upon school preferences that are correlated with race
and ethnicity. This report addresses this issue by analyzing the responses of 1,006 charter school households in
Texas. It first examines the expressed preferences of choosing households, then compares expressed preferences
with behavior. A comparison of the characteristics of the traditional public schools that choosers leave with
the characteristics of the charter schools they choose indicates that race is a good predictor of the choices
that choosing households make. Whites, African Americans, and Latinos transfer into charter schools where their
groups comprise between 11 and 14 percentage points more of the student body than the traditional public schools
they are leaving. © 2002 by the Association for Public Policy Analysis and Management.
Medication use and risk of falls
Authors: Neutel C. Ineke , Perry Sheril , Maxwell Colleen
Published: August 2002

Purpose

Injuries due to falls are an important public health concern, particularly for the elderly, and effective prevention is an ongoing endeavour. The present study has two related objectives: (1) to describe associations between drug use and falls in an institutionalized population, and (2) to identify a high risk subgroup within the larger population.

Methods

The initial analysis was based on a population of 227 residents who were followed over a 1‐year period. Logistic regression techniques were used to estimate odds ratios (ORs) of the association of falls and drug use. The study of potential ‘high‐risk’ groups employed a case–crossover design to estimate the risk of falling associated with starting a new drug course.

Results

Relatively weak ORs for risk of falling were observed for various drug classes; the highest OR was for benzodiazepines (BZD) at OR=1.8

Statistically significant at p < 0.05.

(unadjusted). Residents taking multiple drugs were at particular risk for falling, e.g. an OR of 6.1 for those using 10+ drugs. The case–crossover analysis indicated that residents starting a new BZD/antipsychotic were at very high risk (OR = 11.4) for experiencing a fall.

Conclusions

Residents who took many different types of medications, as well as residents starting a new BZD/antipsychotics were at greatly increased risk of falling. These are high risk groups where increased monitoring or adjustments to drug regimens could lead to prevention of falls. Copyright © 2002 John Wiley & Sons, Ltd.
AB‐type crosslinked polymer networks from vinyl terminated polyurethane and poly(methyl methacrylate)
Authors: Sriram V , Subramani S , Radhakrishnan Ganga
Published: August 2002

Vinyl terminated polyurethanes (VTPUs) were prepared by endcapping isocyanate terminated prepolymers with vinylbenzyl alcohol (VBA). AB‐type crosslinked polymer (ABCP) networks were generated by crosslinking the telechelic polyurethane with methyl methacrylate (MMA) in the presence of 2,2′‐azobisisobutyronitrile (AIBN) as free radical initiator. The spectral, thermal and mechanical properties of ABCPs were studied using Fourier Transform IR, thermogravimetry, dynamic mechanical analysis and stress‐strain analysis. The FTIR results confirm the formation of VBA, TP and ABCPs. Thermal behaviour of crosslinked polymers showed no significant weight loss up to 300 °C, indicating improved thermal stability. Dynamic mechanical tests revealed confinement of phase separation and good damping behaviour for the crosslinked networks. Stress‐strain analysis showed that tensile strength increases with increasing amounts of methyl methacrylate.

© 2001 Society of Chemical Industry
Separation and characterization of poly(styrene‐co‐acrylonitrile)‐graft‐poly(propylene oxide) polymer stabilizer formed in dispersion polymerization of styrene and acrylonitrile in polyether
Authors: Guo Ruiwei , Lu Xiandong , Hua Maosheng , Fang Daobin , Yao Kangde
Published: August 2002

Poly(styrene‐co‐acrylonitrile)‐graft‐poly(propylene oxide) (PSAN‐graft‐PPO), the stabilizer formedin situin the dispersion polymerization of styrene, acrylonitrile and macromonomer PPO maleate in PPO polyol, was separated from ungrafted copolymer PSAN by liquid chromatography. After the determination of the separation conditions by thin‐layer chromatography, the effective separation of the graft polymer from copolymer PSAN was achieved by liquid column chromatography. The graft efficiency and the composition of the graft polymer was determined by UV and1H NMR, and the formation characteristics of the graft polymer are discussed.

© 2001 Society of Chemical Industry
Effect of environmental stress on the mechanical properties of surface treated fly‐ash/polyester particulate composite
Authors: Guhanathan S , Saroja Devi M
Published: August 2002

Fly‐ash (FA) was surface treated with silane coupling agents (CA) vinyltriethoxy silane and aminopropyltrimethoxysilane. Fly‐ash/polyester (FA/GPR) and surface treated fly‐ash/polyester (FA/CA/GPR) particulate composites were made. The composites were exposed to various adverse environmental conditions such as water, boiling water, salt water, acid, alkali, toluene, weather and freezing–thawing cycles for 30 days. The mechanical properties, ie tensile strength, tensile modulus, elongation at break, flexural strength, flexural modulus, compressive strength, impact strength and hardness of FA/GPR and FA/CA/GPR were studied before and after exposure to adverse environmental conditions. The results indicate that the mechanical properties of FA/GPR composites are improved by surface treatment of FA and that their resistance to the various environmental stresses is also enhanced substantially by surface treatment.

© 2002 Society of Chemical Industry
Modeling solar cell degradation in space: A comparison of the NRL displacement damage dose and the JPL equivalent fluence approaches†
Authors: Messenger S. R. , Summers G. P. , Burke E. A. , Walters R. J. , Xapsos M. A.
Published: August 2002

The method for predicting solar cell degradation in space radiation environments developed recently at the US Naval Research Laboratory (NRL) is compared in detail with the earlier method developed at the US Jet Propulsion Laboratory (JPL). Although both methods are similar, the key difference is that in the NRL approach, the energy dependence of the damage coefficients is determined from a calculation of the nonionizing energy loss (NIEL) and requires relatively few experimental measurements, whereas in the JPL method the damage coefficients have to be determined using an extensive set of experimental measurements. The end result of the NRL approach is a determination of a single characteristic degradation curve for a cell technology, which is measured against displacement damage dose rather than fluence. The end‐of‐life (EOL) cell performance for a particular mission can be read from the characteristic curve once the displacement damage dose for the mission has been determined. In the JPL method, the end result is a determination of the equivalent 1 MeV electron fluence, which would cause the same level of degradation as the actual space environment. The two approaches give similar results for GaAs/Ge solar cells, for which a large database exists. Because the NRL method requires far less experimental data than the JPL method, it is more readily applied to emerging cell technologies for which extensive radiation measurements are not available. The NRL approach is being incorporated into a code named SAVANT by researchers at NASA Glenn Research Center. The predictions of SAVANT are shown to agree closely with actual space data for GaAs/Ge and CuInSe2cells flown on the Equator‐S mission. Published in 2001 by John Wiley & Sons, Ltd.
Metamorphic GayIn1−yP/Ga1−xInxAs tandem solar cells for space and for terrestrial concentrator applications at C > 1000 suns
Authors: Dimroth F. , Beckert R. , Meusel M. , Schubert U. , Bett A. W.
Published: August 2002

The use of Ga1−xInxAs instead of GaAs as a bottom solar cell in a GayIn1−yP/Ga1−xInxAs tandem structure increases the flexibility of choosing the optimum bandgap combination of materials for a multijunction solar cell. Higher theoretical efficiencies are calculated and different cell concepts are suggested for space and terrestrial concentrator applications. Various GayIn1−yP/Ga1−xInxAs material combinations have been investigated for the first time and efficiencies up to 24·1% (AM0) and 27·0% (AM1·5 direct) have been reached under one‐sun conditions. An efficiency of 30·0–31·3% was measured for a Ga0·35In0·65P/Ga0·83In0·17As tandem concentrator cell with prismatic cover at 300 suns. The top and bottom cell layers of this structure are grown lattice‐matched to each other, but a large mismatch is introduced at the interface to the GaAs substrate. This cell structure is well suited for the use in next‐generation terrestrial concentrators working at high concentration ratios. For the first time a cell efficiency up to 29–30% has been measured at concentration levels up to 1300 suns. A small prototype concentrator with Fresnel lenses and four tandem solar cells working at C = 120 has been constructed, with an outdoor efficiency of 23%. Copyright © 2001 John Wiley & Sons, Ltd.
Flexible CdTe solar cells on polymer films
Authors: Tiwari A. N. , Romeo A. , Baetzner D. , Zogg H.
Published: August 2002

Lightweight and flexible CdTe/CdS solar cells on polyimide films have been developed in a ‘superstrate configuration’ where the light is absorbed in CdTe after passing through the polyimide substrate. The average optical transmission of the approximately 10‐μm‐thin spin‐coated polyimide substrate layer is more than ∼75% for wavelengths above 550 nm. RF magnetron sputtering was used to grow transparent conducting ZnO:Al layers on polyimide films. CdTe/CdS layers were grown by evaporation of compounds, and a CdCl2annealing treatment was applied for the recrystallization and junction activation. Solar cells of 8·6% efficiency with Voc = 763 mV, Isc = 20·3 mA/cm2and FF = 55·7% were obtained. Copyright © 2001 John Wiley & Sons, Ltd.
Photovoltaic thin‐film technology based on hydrogenated amorphous silicon
Authors: Lechner P. , Schade H.
Published: August 2002

Solar modules based on amorphous silicon combine a number of properties that lead to a wide range of attractive applications, from watch dials to roof integration and semitransparent insulating glazing. The specificities of manufacturing are described, and it can be shown that they ultimately render competitive manufacturing costs and hence total system costs sufficiently low to offset the drawback of lower efficiencies. Copyright © 2002 John Wiley & Sons, Ltd.
Measuring perceived social support: Development of the child and adolescent social support scale (CASSS)
Authors: Kerres Malecki Christine , Kilpatrick Demary Michelle
Published: August 2002

The measurement of students' social support has become a popular topic in education and psychology, yet measurement tools in this area are limited. In this study, we use a large, representative sample to conduct confirmatory factor, reliability, and correlational analyses of scores on the Child and Adolescent Social Support Scale (CASSS; Malecki, Demaray, Elliott, & Nolten, 1999). These analyses revealed evidence of reliability, a four‐factor structure (Parent, Teacher, Classmate, and Close Friend subscales), and construct validity. The results of this study indicate that the CASSS covaries as predicted with the clinically important constructs of self‐concept, social skills, and behavioral indicators. There is evidence that the CASSS can be used to understand children and adolescents' perceived social support. © 2002 John Wiley & Sons, Inc.
Adolescents' mobility histories and present social adjustment
Authors: Norford Bradley C. , Medway Frederic J.
Published: August 2002

This study compared three groups of high school students: frequent movers (6 to 13 relocations), moderate movers (3 to 5 relocations), and nonmovers on depression, appraised social support, and participation in extracurricular activities. The sample was examined further according to the primary reason for relocation, the timing (before or after the seventh grade), and whether student shyness, socioeconomic status (SES), and family cohesion influenced any potential effects. Despite methodological improvements over past research including the exclusion of students who recently moved or reported other current stressors, few significant effects were obtained. Findings did reveal that students whose families relocated because of divorce and those who experienced early life relocations had lower levels of participation in extracurricular activities. Students reported less negative effects of relocation than did their mothers. Further, mothers' negative attitudes toward relocation were significantly correlated with student depression. It is concluded that there is little current or prior research evidence that high rates of social mobility are associated with long‐term social adjustment problems for adolescents. © 2002 John Wiley & Sons, Inc.
School demographic variables and out‐of‐school suspension rates: A quantitative and qualitative analysis of a large, ethnically diverse school district
Authors: Mendez Linda M. Raffaele , Knoff Howard M. , Ferron John M.
Published: August 2002

This study examined out‐of‐school suspensions (OSS) in a large, ethnically diverse school district using both quantitative and qualitative procedures. Pearson product moment correlations and semi‐partial correlations were used to identify those school‐level variables that showed the strongest relationships to the duplicated OSS rate among elementary schools (n = 97) and secondary schools (n = 45). Additionally, interviews were conducted with administrators and student support personnel from the 24 schools in the district with the highest suspension rates and 24 demographically matched schools with significantly lower suspension rates. The majority of these schools served a high percentage of children from low socioeconomic backgrounds. Although the correlational analyses indicated that student demographic variables (e.g., percentage of White students, percentage of Black students, percentage of students receiving free or reduced price lunch) were strongly related to a school's suspension rate, the school comparisons showed that not all schools serving a high percentage of children placed at risk have high suspension rates. Implications of the findings for school discipline reform are discussed. © 2002 Wiley Periodicals, Inc.
Teacher ratings of behavior among African American and Caucasian children during the first two years of school
Authors: Sbarra David A. , Pianta Robert C.
Published: August 2002

This article prospectively examines teacher‐rated behavior problems and competencies during the first 2 years of formal schooling among African American (n = 190) and Caucasian (n = 350) children. A significant main effect for race was found for both behavior problems and competencies in repeated measures analyses conducted across kindergarten and first‐grade teacher ratings. A time × race interaction indicated that teachers rated Caucasian children's competence as stable over time, whereas their African American peers were rated as less competent. According to these data, African American children did not maintain age‐appropriate school‐based competencies in task orientation and frustration tolerance. No interaction effects were found for a gender × time term for either competencies or behavior problems, suggesting that African American boys do not show more disturbed behavior in the early school years. Behavior trajectories are discussed in terms of the need for competence‐enhancing interventions aimed at early school transitions, particularly for African American children. © 2001 John Wiley & Sons, Inc.
Radical polymerization of vinyl thiocyanatoacetate: Participation of group‐transfer mechanism
Authors: Sato Tsuneyuki , Mukuno Hidekazu , Ishida Hirotaka , Seno Makiko , Hirano Tomohiro
Published: August 2002

Vinyl thiocyanatoacetate (VTCA) was synthesized, and its radical polymerization behavior was studied in acetone with dimethyl 2,2′‐azobisisobutyrate (MAIB) as an initiator. The initial polymerization rate (Rp) at 60 °C was expressed by Rp = k[MAIB]0.6±0.1 [VTCA]1.0±0.1 where k is a rate constant. The overall activation energy of the polymerization was 112 kJ/mol. The number‐average molecular weights of the resulting poly (VTCA)s (1.4–1.6 × 104) were almost independent of the concentrations of the initiator and monomer, indicating chain transfer to the monomer. The chain‐transfer constant to the monomer was estimated to be 9.6 × 10−3 at 60 °C. According to the 1H and 13C NMR spectra of poly (VTCA), the radical polymerization of VTCA proceeded through normal vinyl addition and intramolecular transfer of the cyano group. The cyano group transfer became progressively more important with decreasing monomer concentration. © 2002 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 573–582, 2002; DOI 10.1002/pola.10137
Radiation‐grafted ion‐exchange membranes: Influence of the initial matrix on the synthesis and structure
Authors: Walsby Nadia , Sundholm Franciska , Kallio Tanja , Sundholm Göran
Published: August 2002

A series of commercial fluoropolymer films was irradiated with an electron beam, grafted with styrene, and sulfonated. The influence of the initial fluoropolymer on the grafting yields and the properties of the grafted and sulfonated membranes were investigated. The same synthesis procedure can be followed for most fluoropolymers and samples with a similar degree of grafting, and a homogenous polystyrene distribution can be prepared by varying the absorbed dose. The main difference among different fluoropolymer‐based membranes is the water uptake from liquid water that has a roughly linear dependence on the crystallinity of the sample. The more amorphous the initial material, the greater the water uptake. Mechanical properties of the membranes at 50% relative humidity differ less than those of the starting materials and are comparable to those of Nafion® 105. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3008–3017, 2001
Kinetics of thiol–ene and thiol–acrylate photopolymerizations with real‐time fourier transform infrared
Authors: Cramer Neil B. , Bowman Christopher N.
Published: August 2002

We used real‐time Fourier transform infrared to monitor the conversion of both thiol and ene (vinyl) functional groups independently during photoinduced thiol–ene photopolymerizations. From these results, the stoichiometry of various thiol–ene and thiol–acrylate polymerizations was determined. For thiol–ene polymerizations, the conversion of ene functional groups was up to 15% greater than the conversion of thiol functional groups. For stoichiometric thiol–acrylate polymerizations, the conversion of the acrylate functional groups was roughly twice that of the thiol functional groups. With kinetic expressions for thiol–acrylate polymerizations, the acrylate propagation kinetic constant was found to be 1.5 times greater than the rate constant for hydrogen abstraction from the thiol. Conversions of thiol–acrylate systems of various initial stoichiometries were successfully predicted with this ratio of propagation and chain‐transfer kinetic constants. Thiol–acrylate systems with different initial stoichiometries exhibited diverse network properties. Thiol–ene systems were initiated with benzophenone and 2,2‐dimethoxy‐2‐phenylacetophenone as initiators and were also polymerized without a photoinitiator. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3311–3319, 2001
Correlation of the melting behavior and copolymer composition distribution of Ziegler–Natta‐catalyst and single‐site‐catalyst polyethylene copolymers
Authors: Mirabella Francis M.
Published: August 2002

The multimodal differential scanning calorimetry melting endotherms observed for commercial linear low‐density polyethylenes are due to broad and multimodal short‐chain‐branching distributions. Multiple peaks, observed in melting endotherms of isothermally melt‐crystallized and compositionally homogeneous polyethylene copolymers are due to intrachain heterogeneity. This intrachain heterogeneity is quantified by the distribution of ethylene sequence lengths within the chains. These compositionally homogeneous copolymers undergo a primary crystallization, which produces a population of thicker lamellae, creating a network that places severe restrictions on segment transport in subsequent secondary crystallization, which produces a population of thinner crystals. The restrictions on segment transport imposed by the initial network created by the primary crystallization of thicker lamellae severely limits the total crystallinity achieved in the random copolymers studied. The solution crystallization of such copolymers produces a continuous distribution due to more facile segment transport in a dilute solution, in contradistinction to the multimodal distribution produced in the melt crystallization. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2800–2818, 2001
Micellar structure and mechanical properties of block copolymer‐modified epoxies
Authors: Dean J. M. , Lipic P. M. , Grubbs R. B. , Cook R. F. , Bates F. S.
Published: August 2002

Amphiphilic block copolymers provide a unique means for toughening epoxy resins because they can self‐assemble into different inclusion shapes before epoxy curing. The two examples reported here are spherical micelles and vesicles, which form in blends containing epoxy and symmetric or asymmetric poly(ethylene oxide)–poly(ethylene‐alt‐propylene) (PEO–PEP) block copolymer with PEO volume fractions of 0.5 and 0.26, respectively. The vesicles and spherical micelles were characterized by transmission electron microscopy and small‐angle X‐ray scattering (SAXS), respectively. SAXS data from the spherical micelles were fit to the Percus–Yevick model for a liquid‐like packing of spheres with hard‐core interactions. Mechanical properties of spherical‐micelle‐modified and vesicle‐modified epoxies in the dilute limit are compared. The glass‐transition temperature and Young's (storage) modulus were tested with dynamic mechanical spectroscopy, and compact‐tension experiments were performed to determine the critical plane‐strain energy release rate for fracture. Vesicles were most effective in improving the epoxy fracture resistance. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2996–3010, 2001
Degradation of a poly(ester urethane) elastomer. II. Kinetic modeling of the hydrolysis of a poly(butylene adipate)
Authors: Salazar Michael R. , Pack Russell T
Published: August 2002

In preparation for studying the kinetics of the hydrolysis of Estane® 5703, published hydrolysis data for a similar poly(butylene adipate) (herein called 63 PBA) have been modeled. Poly(ester urethanes) are known to degrade by acid‐catalyzed hydrolysis of the ester links, and the data on 63 PBA show that this degradation is reversible at low relative humidities (RHs). Previous work with these data was unable to fit them with concentration‐independent rate coefficients. It is shown herein that, with the water‐concentration model of the preceding article and the AAC2 mechanism of reversible hydrolysis/esterification, the experimental kinetic data that vary across temperature, RH, and starting molecular weight can be fit with a single set of concentration‐independent rate coefficients. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 40: 192–200, 2002
Preparation and characterization of a nanoscale poly(vinyl alcohol) fiber aggregate produced by an electrospinning method
Authors: Ding Bin , Kim Hak‐Yong , Lee Se‐Chul , Shao Chang‐Lu , Lee Douk‐Rae , Park Soo‐Jin , Kwag Gyu‐Beom , Choi Kyung‐Ju
Published: August 2002

Nanoscale poly(vinyl alcohol) (PVA) fiber (100–500 nm) aggregates were prepared with an electrospinning technique. Additionally, a chemical crosslinking method was used to crosslink the nanoscale PVA fiber aggregates. Differential scanning calorimetry, wide‐angle X‐ray diffraction, and scanning electron microscopy techniques were employed to characterize the PVA fiber aggregates. The different crosslinking densities of the PVA fiber aggregates were obtained through the control of the weight percentage of glyoxal to PVA. The crosslinking densities due to heat treatment and chemical crosslinking were studied. The influence of heat treatment could be neglected in contrast to chemical crosslinking when the curing temperature was 120 °C. The primary factor that affected the crosslinking density was the volume of the chemical crosslinking agent. The results showed that the properly crosslinked PVA fiber aggregates had better antiwater solubility and mechanical properties than the noncrosslinked PVA fiber aggregates. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1261–1268, 2002
Compressed‐gas‐induced crystallization in tert‐butyl poly(ether ether ketone)
Authors: Handa Y. Paul , Zhang Zhiyi , Roovers Jacques
Published: August 2002

tert‐Butyl‐substituted poly(ether ether ketone) (tBuPEEK), which does not undergo crystallization with thermal annealing, crystallizes readily when treated with compressed CO2. The dissolved CO2 causes a reduction in the glass‐transition temperature of the polymer–gas system and enhances the chain mobility of the macromolecules, thereby bringing about crystallization. In the presence of CO2, crystallization is increasingly favored with increasing CO2 pressure and treatment temperature. The melting point of tBuPEEK crystals increases linearly with the CO2 pressure applied in the treatment, indicating an increase in the order and/or size of the crystals. The extent of crystallinity increases when small amounts of methanol or dichloromethane are used as a cosolute with CO2. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1505–1512, 2001
Near‐surface structure formation in chemically imidized polyimide films
Authors: Dabral Mahendra , Xia Xinyun , Gerberich W. W. , Francis L. F. , Scriven L. E.
Published: August 2002

Free‐standing polyimide films are manufactured by the chemical imidization of linear, soluble polymeric precursors. The reactive solution is coated onto a heated substrate, peeled off after partial imidization, and then dried and cured as a free‐standing film. Adhesive bonds to the cast side of the final film more strongly than to the air side. Near‐surface elastic moduli of film samples were measured with a nanoindentation setup. Samples were annealed at different final temperatures. The air side of the samples annealed at 400 °C had a higher modulus of 1.4 GPa than the 0.8 GPa of the casting side. This difference diminished as the annealing temperature was raised to 460 °C. Polyamic acid and polyimide exhibit phase transitions from disordered, isotropic solutions to ordered, liquid‐crystalline states. A theoretical model of drying and curing demonstrates formation of a gradient in conversion and ordering: the air side vitrifies at a lower solvent content, lower conversion, and higher ordering; the casting side, at a greater solvent content, higher conversion, and less ordering. Subsequent high‐temperature drying and curing of the free‐standing films removes solvent, completes reaction, and nematically orders both sides. However, longer times and higher temperature annealing are needed to bring the two sides to their common equilibrium state of nematic order. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1824–1838, 2001
Measuring religious faith in cancer patients: reliability and construct validity of the Santa Clara strength of religious faith questionnaire
Authors: Sherman Allen C. , Simonton Stephanie , Adams Dawn C. , Latif Umaira , Plante Thomas G. , Burns S. Kaay , Poling Tom
Published: August 2002

Growing attention has focused on associations between religious involvement and health outcomes for cancer patients. Unfortunately, research has been hampered by lack of measures suitable for use in oncology settings. This study examined the performance of one recently developed measure, the Santa Clara Strength of Religious Faith Questionnaire (SCSORF). Initial investigations with cancer patients in a bone marrow transplant program and with non‐oncology patients yielded promising results. This study provided additional information about temporal stability and convergent validity.

The measure was evaluated in two well‐defined samples: (1) 95 breast cancer patients, and (2) 53 healthy young adults. Most of the cancer patients had recent diagnoses and localized or regional disease. In each sample, the instrument demonstrated high test–retest reliability (r's=0.82–0.93) and internal consistency (r's=0.95–0.97). It displayed strong correlations with measures of intrinsic religiosity (r's=0.67–0.82, p<0.0001), and moderate correlations with organizational religiosity (r's=0.61–069, p<0.0001), non‐organizational religiosity (r's=0.52–0.55, p<0.0001), comfort from religion (r=0.58, p<0.0001), and ratings of self as religious (r=0.58, p<0.0001). Among cancer patients, scores were significantly associated with optimism (r=0.30, p<0.01), but not with openness of family communication about cancer or perceived social support. These data build on previous findings with cancer patients, and suggest that the SCSORF may be a useful measure of religious faith in oncology settings. Copyright © 2001 John Wiley & Sons, Ltd.
Congenital lung disease: A plea for clear thinking and clear nomenclature
Authors: Bush Andrew
Published: August 2002

Antenatal ultrasound has allowed the discovery of abnormalities which in the past often escaped detection. It may be unclear what advice to offer. Many large lung malformations seen at the routine 20‐weeks gestation scan have largely disappeared at term. There is now even more confusion in terms of how these malformations should be described. The nomenclature of congenital lung disease was never very clear, with terms such as sequestrated segment, cystic adenomatoid malformation, hypoplastic lung, and malinosculation being used to describe often overlapping abnormalities. However, today these terms are used inconsistently in the ante‐ and postnatal periods. For example, congenital cystic adenomatoid malformation (CCAM) is used prenatally to describe a lesion which may well disappear before birth,1 but is used postnatally to describe an abnormality which may require lobectomy. CCAM may have a pulmonary arterial supply, or be supplied like a sequestration from the aorta, and histological features of both lesions may coexist.2 Thus, a complete reappraisal of the nomenclature of congenital lung disease is timely; this review does not discuss treatment options. Pediatr Pulmonol. 2001; 32:328–337. © 2001 Wiley‐Liss, Inc.
Presence of cystic fibrosis‐related diabetes mellitus is tightly linked to poor lung function in patients with cystic fibrosis: Data from the European Epidemiologic Registry of Cystic Fibrosis
Authors: Koch C. , Rainisio M. , Madessani U. , Harms H.K. , Hodson M.E. , Mastella G. , McKenzie S.G. , Navarro J. , Strandvik B.
Published: August 2002

Data derived from a cross‐sectional analysis of 7,566 patients stratified into six age groups were used to compare lung function, body mass index (BMI), and weight for age in patients with and without cystic fibrosis‐related diabetes mellitus (CFDM).

The presence of CFDM was tightly linked to poor lung function, regardless of age. The mean value of FEV1 % predicted in the age groups < 10, 10–< 15, 15–< 20, 20–< 25, 25–< 30, and 30 years or older were 87%, 77%, 69%, 58%, 55%, and 53% in the nondiabetic cystic fibrosis (CF) patients as compared to 79%, 66%, 55%, 49%, 46%, and 44% in the diabetic CF patients. BMI and weight for age were also lower in diabetic than nondiabetic CF patients in all age groups, except for BMI in the youngest patients. The difference in lung function and in nutritional parameters between diabetic and nondiabetic CF patients was not linked to presence or absence of any specific pathogen in the lower respiratory tract.

These results confirm and extend those of earlier studies in smaller numbers of patients, and they clearly identify CFDM as a powerful determinant of severe lung disease and reduced survival in patients with CF and diabetis mellitus. Pediatr Pulmonol. 2001; 32:343–350. © 2001 Wiley‐Liss, Inc.
Establishment and characterization of osseous prostate cancer models: Intra‐tibial injection of human prostate cancer cells
Authors: Corey Eva , Quinn Janna E. , Bladou Franck , Brown Lisha G. , Roudier Martine P. , Brown Julie M. , Buhler Kent R. , Vessella Robert L.
Published: August 2002

BACKGROUND

To improve the therapy of advanced prostate cancer (CaP), it is critical to develop animal models that mimic CaP bone metastases. Unlike the human disease, CaP xenograft models rarely metastasize spontaneously to bone from the orthotopic site of primary tumor growth.

METHODS

Single‐cell suspensions of LNCaP, PC‐3, LuCaP 35, and LuCaP 23.1 CaP cells were injected directly into tibia of SCID mice. Immunohistochemistry and bone histomorphometrical analyses were performed to characterize these osseous‐CaP models.

RESULTS

LuCaP 23.1 yields an osteoblastic response, LNCaP yields mixed lesions, and LuCaP 35 and PC‐3 result in osteolytic responses. We have detected osteoprotegerin, RANK ligand, parathyroid hormone‐related protein, and endothelin‐1, proteins associated with bone growth and remodeling, in the CaP cells grown in the bone.

CONCLUSIONS

These animal models can be used to study biological interactions, pathways, and potential therapeutic targets, and also to evaluate new agents for treatment and prevention of CaP bone metastasis. Prostate 52: 20–33, 2002. © 2002 Wiley‐Liss, Inc.
Melatonin elicits nuclear exclusion of the human androgen receptor and attenuates its activity
Authors: Rimler Avi , Culig Zoran , Levy‐Rimler Galit , Lupowitz Zippora , Klocker Helmut , Matzkin Haim , Bartsch Georg , Zisapel Nava
Published: August 2002

Background

The androgen receptor (AR) promotes growth and functionality of androgen sensitive benign and cancer tissues. The pineal hormone melatonin is an androgen protagonist in vivo and in vitro. The interference of melatonin in the AR cascade was explored.

Methods

The effects of melatonin on AR expression, level, agonist and androgen‐response element (ARE) binding, reporter gene activity and intracellular localization were explored in prostate cancer LNCaP cell line.

Results

Melatonin increased immunoreactive AR cells in the absence and presence of dihydrotestosterone. Despite this increase and maintenance of AR agonist binding capacity, the androgen‐induced reporter gene activity and suppression of AR‐mRNA were attenuated. Immunocytochemical analysis and subcellular fractionation studies revealed nuclear exclusion of AR by melatonin.

Conclusions

The melatonin‐mediated nuclear exclusion of the AR may explain the attenuation of AR activity in the prostate cancer cells. This is the first demonstration of a hormone‐induced mislocalization of the AR in prostate epithelial cells and may represent a novel route for regulating AR activity. Prostate 49:145–154, 2001. © 2001 Wiley‐Liss, Inc.
Prediction of protein cellular attributes using pseudo‐amino acid composition
Authors: Chou Kuo‐Chen
Published: August 2002

The cellular attributes of a protein, such as which compartment of a cell it belongs to and how it is associated with the lipid bilayer of an organelle, are closely correlated with its biological functions. The success of human genome project and the rapid increase in the number of protein sequences entering into data bank have stimulated a challenging frontier: How to develop a fast and accurate method to predict the cellular attributes of a protein based on its amino acid sequence? The existing algorithms for predicting these attributes were all based on the amino acid composition in which no sequence order effect was taken into account. To improve the prediction quality, it is necessary to incorporate such an effect. However, the number of possible patterns for protein sequences is extremely large, which has posed a formidable difficulty for realizing this goal. To deal with such a difficulty, the pseudo‐amino acid composition is introduced. It is a combination of a set of discrete sequence correlation factors and the 20 components of the conventional amino acid composition. A remarkable improvement in prediction quality has been observed by using the pseudo‐amino acid composition. The success rates of prediction thus obtained are so far the highest for the same classification schemes and same data sets. It has not escaped from our notice that the concept of pseudo‐amino acid composition as well as its mathematical framework and biochemical implication may also have a notable impact on improving the prediction quality of other protein features. Proteins 2001;43:246–255. © 2001 Wiley‐Liss, Inc.
Protein molecular dynamics with the generalized born/ACE solvent model
Authors: Calimet Nicolas , Schaefer Michael , Simonson Thomas
Published: August 2002

Implicit solvent models are increasingly important for the study of proteins in aqueous solution. Here, the generalized Born (GB) solvent polarization model as implemented in the analytical ACE potential [Schaefer and Karplus (1996) J Phys Chem 100:1578] is used to perform molecular dynamics simulations of two small, homologous proteins: the immunoglobulin‐binding domain of streptococcal protein G and the Ras binding domain of Raf. Several model parameterizations are compared through more than 60 ns of simulation. Results are compared with two simpler solvent models—an accessible surface area model and a distant‐dependent dielectric model, with finite‐difference Poisson calculations, with existing explicit solvent simulations, and with experimental data. The simpler models yield stable but distorted structures. The best GB/ACE implementation uses a set of atomic Voronoi volumes reported recently, obtained by averaging over a large database of crystallographic protein structures. A 20% reduction is applied to the volumes, compensating in an average sense for an excessive de‐screening of individual charges inherent in the ACE self‐energy and for an undersolvation of dipolar groups inherent in the GB screening function. This GB/ACE parameterization yields stable trajectories on the 0.5–1‐ns time scale that deviate moderately (∼1.5–2.5 Å) from the X‐ray structure, reproduce approximately the surface distribution of charged, polar, and hydrophobic groups, and reproduce accurately backbone flexibility as measured by amide NMR‐order parameters. Over longer time scales (1.5–3 ns), some of the protein G runs escape from the native energy basin and deviate strongly (3 Å) from the native structure. The conformations sampled during the transition out of the native energy basin are overstabilized by the GB/ACE solvation model, as compared with a numerical treatment of the full dielectric continuum model. Proteins 2001;45:144–158. © 2001 Wiley‐Liss, Inc.
Structure and diversity of insect nicotinic acetylcholine receptors
Authors: Tomizawa Motohiro , Casida John E
Published: August 2002

The nicotinic acetylcholine receptor (nAChR) is an agonist‐regulated ion‐channel complex responsible for rapid neurotransmission. The vertebrate nAChR, assembled from five homologous subunits, penetrates the synaptic membrane. Different subunit combinations lead to receptor subtypes with distinctive pharmacological profiles. In comparison with mammalian nAChRs, the insect receptor is poorly understood relative to functional architecture and diversity. Several genes for Drosophila, Locusta and Myzus encoding insect nAChR subunits have been identified, although the functional assembly and presence of different subtypes of these receptors are not defined. The insect nAChR is the primary target site for the neonicotinoid insecticides, thereby providing an incentive to explore its functional architecture with neonicotinoid radioligands, photoaffinity probes and affinity chromatography matrices. This review considers the current understanding of the structure and diversity of insect nAChRs based mainly on recent studies in molecular biology and protein biochemistry.

© 2001 Society of Chemical Industry
The role of tryptophan in the antibacterial activity of a 15‐residue bovine lactoferricin peptide
Authors: Haug Bengt Erik , Svendsen John S
Published: August 2002

Bovine lactoferricin is a 25‐residue antibacterial peptide isolated after gastric cleavage of the iron transporting protein lactoferrin. A 15‐residue fragment, FKCRRWQWRMKKLGA of this peptide sustains most of the antibacterial activity. In this truncated sequence, the two Trp residues are found to be essential for antibacterial activity. The anchoring properties of Trp, as have been observed in membrane proteins, are believed to be important for the interaction of Trp containing antibacterial peptides with bacterial cell membranes. We have investigated the molecular properties which make Trp important for the antibacterial activity of the 15‐residue peptide by replacing Trp with natural and unnatural aromatic amino acids. This series of peptides was tested for antibacterial activity against Echerichia coli and Staphylococcus aureus. We found that neither the hydrogen bonding ability nor the amphipathicity of the indole system are essential properties for the effect of Trp on the antibacterial activity of the peptides. Replacement of Trp with residues containing aromatic hydrocarbon side chains gave the most active peptides. We propose that aromatic hydrocarbon residues are able to position themselves deeper into the bacterial cell membrane, making the peptide more efficient in disrupting the bacterial cell membrane. From our results the size, shape and aromatic character of Trp seem to be the most important features for the activity of this class of Trp containing antibacterial peptides. Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd.
Effect of fire on concrete and concrete structures
Authors: Khoury Gabriel Alexander
Published: August 2002

The behaviour of concrete in fire depends on its mix proportions and constituents and is determined by complex physicochemical transformations during heating. Normal‐strength concretes and high‐performance concretes microstructurally follow similar trends when heated, but ultra‐high‐performance concrete behaves differently. A key property unique to concrete amongst structural materials is transient creep. Any structural analysis of heated concrete that ignores transient creep will yield erroneous results, particularly for columns exposed to fire. Failure of structural concrete in fire varies according to the nature of the fire; the loading system and the type of structure. Failure could occur from loss of bending or tensile strength; loss of bond strength; loss of shear or torsional strength; loss of compressive strength; and spalling of the concrete. The structural element should, therefore, be designed to fulfil its separating and/or load‐bearing function without failure for the required period of time in a given fire scenario. Design for fire resistance aims to ensure overall dimensions of the section of an element sufficient to keep the heat transfer through this element within acceptable limits, and an average concrete cover to the reinforcement sufficient to keep the temperature of the reinforcement below critical values long enough for the required fire resistance period to be attained. The prediction of spalling – hitherto an imprecise empirical exercise – is now becoming possible with the development of thermohydromechanical nonlinear finite element models capable of predicting pore pressures. The risk of explosive spalling in fire increases with decrease in concrete permeability and could be eliminated by the appropriate inclusion of polypropylene fibres in the mix and/or by protecting the exposed concrete surface with a thermal barrier. There are three methods of assessment of fire resistance: (a) fire testing; (b) prescriptive methods, which are rigid; and (c) performance‐based methods, which are flexible. Performance‐based methods can be classified into three categories of increasing sophistication and complexity: (a) simplified calculations based on limit state analysis; (b) thermomechanical finite element analysis; and (c) comprehensive thermohydromechanical finite element analysis. It is only now that performance‐based methods are being accepted in an increasing number of countries.
Prestressed fibre‐reinforced polymer laminates for strengthening structures
Authors: El‐Hacha R , Wight RG , Green MF
Published: August 2002

Bonding fibre‐reinforced polymer (FRP) laminates to the surface of a structural component is an effective technique for strengthening structures. The laminates may be used even more efficiently by prestressing the fibre, and this technique has been the focus of recent innovative work. This review focuses on the characteristics of prestressed FRP laminates, the techniques that have been developed, and field applications. Recent strengthening work with non‐prestressed laminates is also summarized.