bluuebunny/crossref_metadata_2025 huggingface dataset:
Psychometric testing of the NEECHAM confusion scale among patients with hip fracture
Authors: Johansson Inger S. , Hamrin Elisabeth K.F. , Larsson Gerry
Published: August 2002

The main aim of this study was to assess the reliability and validity of a Swedish translation of the NEECHAM Confusion Scale among 73 patients having surgery for hip fractures. Cronbach's alpha before and 7 days after surgery were .73 and .82, respectively. Principal‐component analyses yielded three factors explaining 69% of the variance of the variables preoperatively and 73.6% of the variance 7 days postoperatively. Four months after discharge vital function, factor II in the NEECHAM scale, significantly predicted the total score on the Ferrans and Powers Quality of Life Index. Items reflecting information processing, behavior, and urinary continence, factor I, also predicted functional capacity, using the Standardized Practical Equipment test, a tool measuring instrumental daily activity. The scale seems to be a reliable and valid instrument for evaluating acute confusional state among patients with hip fracture. © 2002 Wiley Periodicals, Inc. Res Nurs Health 25:203–211, 2002
Role integration and perceived health in Asian American women caregivers
Authors: Jones Patricia S. , Jaceldo Karen B. , Lee Jerry R. , Zhang Xinwei E. , Meleis Afaf I.
Published: August 2002

In this study, role involvement, role integration (including role stress and role satisfaction), and perceived health were examined in 50 Asian American women who were caregivers of aging parents in addition to being wives, mothers, and employees. Their mean age was 47.8 years. Twenty‐nine of the participants were Chinese and 21 Filipino, with an average length of caregiving for each group of 11 years. All participants were born outside the United States. Instruments used in the study were translated and back‐translated into Chinese and Tagalog and tested for validity and reliability. The association of role involvement, role integration, role stress, and role satisfaction with perceived physical and psychological health in the combined and separate groups was examined. Role involvement was not associated with health in the combined group of caregivers but was associated with overall health in the sample of Chinese women. Role integration was positively associated with all three perceived health measures in the Filipino group but not in the Chinese group. Role satisfaction was consistently high in both groups. Role satisfaction and psychological well‐being were significantly correlated for the combined group and for the Filipino caregivers. Total role stress was significantly correlated with overall health and current health only in the combined group. Thus, support that helps to decrease role stress and to increase role satisfaction may be more effective than efforts to decrease the extent of role involvement. © 2001 John Wiley & Sons, Inc. Res Nurs Health 24: 133–144, 2001
Relationships among maternal–fetal attachment, prenatal depression, and health practices in pregnancy
Authors: Lindgren Kelly
Published: August 2002

The purpose of this study was to investigate a conceptual model in which depression was proposed to have direct negative effects on positive health practices as well as indirect negative effects through maternal–fetal attachment (MFA). Participants were 252 adult pregnant women, between 20 and 40 weeks postgestation, who were recruited from five prenatal care sites. Data were collected using mailed self‐report instruments measuring MFA, depression, health practices, and demographic and pregnancy information. Hierarchical regression was used to examine direct and indirect effects of depression, person characteristics (maternal age, pregnancy risk status, parity, ethnicity, education, income, marital status), and MFA on health practices. Results of the study supported the conceptual model. Higher education, lower parity, and being partnered predicted more positive health practices (p <05). After controlling for person characteristics, depression was found to be a significant predictor of MFA. Both depression and MFA were significant predictors of positive health practices but in opposite directions. Depression had a negative relationship and MFA a positive relationship with positive health practices. © 2001 John Wiley & Sons, Inc. Res Nurs Health 24: 203–217, 2001
Robust deadbeat pole assignment with gain constraints: an LMI optimization approach
Authors: Tam Hei Ka , Lam James
Published: August 2002

This paper considers a kind of robust pole assignment problem for discrete‐time systems. A recently developed a posteriori measure of closed‐loop eigenvalue sensitivity suitable for MIMO deadbeat regulator design is minimized during the search of the state feedback gain. The problem is cast into an LMI‐based convex optimization task in which constraints on the size of feedback gain can be catered naturally. The proposed pole assignment algorithm can also be used to find the minimum feedback gain with respect to different norms. A numerical example is then employed to illustrate the effectiveness of the method. Copyright © 2000 John Wiley & Sons, Ltd.
Policy transfer and reversal: customary land registration from Africa to Melanesia
Authors: Larmour Peter
Published: August 2002

Ideas and laws about land titling were transferred from East Africa to Melanesia in the 1950s and 1960s. There they provoked a nationalist reaction, and new sources of ideas became influential: from other South Pacific countries in the 1970s, from economic theory in the 1980s, and from the World Bank in the 1990s. Research has cast doubt on the effectiveness of earlier schemes, though little has emerged in Melanesia to take their place. This article analyses the process as one of failed ‘policy transfer’ in which the beneficiaries of the policy may see it quite differently from the government and donors who promote it. Copyright © 2002 John Wiley & Sons, Ltd.
Semilobar holoprosencephaly in a 46,XY female fetus
Authors: Witters Ingrid , Moerman Philippe , Muenke Maximilian , Van Assche Frans‐André , Devriendt Koen , Legius Eric , Van Schoubroeck Dominique , Fryns Jean‐Pierre
Published: August 2002

We report the prenatal echographic diagnosis of holoprosencephaly (HPE) at 11 weeks' gestation. Fetopathological examination revealed an unusual variant of semilobar HPE with middle interhemispheric fusion associated with sex‐reversal: 46,XY normal male karyotype, normal external and internal female genitalia and streak gonads. Copyright © 2001 John Wiley & Sons, Ltd.
FISH analysis of fetal nucleated red blood cells from CVS washings in cases of aneuploidy
Authors: Heleen Schuring‐Blom G. , Hoovers Jan M. N. , van Lith Jan M. M. , Knegt Alida C. , Leschot Nico J.
Published: August 2002

Objective

In chorionic villus sampling (CVS) the chromosome analysis is inconclusive in 1–2% of the samples. In many cases follow‐up amniocentesis is performed. Fetal nucleated red blood cells (FNRBCs) are present in washings of chorionic villus samples. We wanted to establish whether analysis of these true fetal cells, using fluorescence in situ hybridization (FISH), could support the CVS karyotype.

Methods

We analysed washings of first trimester chorionic villi from non‐mosaic 45,X (n=6) and full trisomy 18 cases (n=7). FNRBCs were identified by immunostaining and FISH was performed with chromosome‐specific probes for X, Y and 18.

Results

In all 13 samples FNRBCs were present (between 4 and 30 cells per sample). Five cases of monosomy X showed one X signal in 89–100% of the nuclei; in the other case 50% of the nuclei displayed one signal. In the trisomy 18 cases three spots were seen in 60–100% of the cells.

Conclusion

The CVS aneuploidy was confirmed in FNRBCs in all samples, so FISH on FNRBCs can be used in cases of non‐mosaic numerical chromosomal abnormalities. This test can confirm a CVS diagnosis of monosomy X or trisomy 18 and thus minimize the risk for false‐positive diagnoses. An additional invasive test may be prevented. Copyright © 2001 John Wiley & Sons, Ltd.
Evaluation of a fetus at risk for dihydropteridine reductase deficiency by direct mutation analysis using denaturing gradient gel electrophoresis
Authors: Serap Kalkanoğlu H. , Romstad Anne , Coşkun Turgay , Güttler Flemming
Published: August 2002

Dihydropteridine reductase (DHPR) is an enzyme involved in the recycling of tetrahydrobiopterin (BH4), which is an obligate co‐factor of the aromatic amino acid hydroxylases. DHPR deficiency is a rare, autosomal recessive disorder caused by mutations in the QDPR gene. DHPR‐deficient patients are diagnosed by a lack of response to a low phenylalanine diet and by severe neurological symptoms. Final diagnosis is made by measurements of neurotransmitters and pterin metabolites in cerebrospinal fluid (CSF) and urine, in addition to DHPR enzyme activity, which can be assessed in whole red blood cells. Treatment of DHPR deficiency can be difficult and the outcome is not always satisfying, even if all treatment strategies are followed. Therefore prenatal diagnosis is of great importance in affected families. Prenatal diagnosis is possible by measuring DHPR activity in different cell types but this is time consuming. More than 25 different mutations have to date been identified in the QDPR gene and direct identification of a mutation in a fetus would be easy and rapid. We have developed a method based on denaturing gradient gel electrophoresis (DGGE) for the analysis of the QDPR gene. The method is useful for rapid and simultaneous scanning of all exons and flanking intronic sequences of the QDPR gene. We describe the first prenatal diagnosis conducted using this method. Copyright © 2001 John Wiley & Sons, Ltd.
The effect of introducing prompted, systematic, protocol‐based diabetic care in a practice: 18 months of improvement
Authors: Kendrick Denise
Published: August 2002

Objective:

to evaluate the impact of prompted, systematic, protocol‐based care for a general practice diabetic population on glycaemic control, control of hyperlipidaemia and hypertension, and to assess the quality of diabetic care provided.

Setting:

one general practice in Nottingham, UK.

Design:

baseline and follow‐up audit and retrospective cohort study.

Subjects:

all diabetic patients registered with the practice between 1 May 1997 and 1 November 1998.

Outcome measures:

glycaemic (fasting plasma glucose and HbA1c), lipid (serum cholesterol and triglyceride concentrations) and blood pressure control; achievement of process measures relating to diabetic care.

Results:

glycaemic control and serum cholesterol levels improved significantly over an 18 month period, but there was no significant improvement in triglyceride levels or in blood pressure control. At follow‐up the glycaemic and blood pressure control was similar to that achieved in the intensive arm of the UKPDS study. At least 87% of patients had all elements of the recommended annual review.

Conclusions:

improvements in glycaemic and lipid control can be achieved within a short time scale in primary care. There are considerable workload implications to achieving such improvement. The sustainability of improvements in control in primary care is not known, and longer term follow‐up is required to establish this. Copyright © 2000 John Wiley & Sons, Ltd.
The evolution of screening
Authors: Gray J. A. Muir
Published: August 2002

Botany is usually considered to be the gentlest of sciences with botanists being regarded as people who study relatively safe specimens, compared with, for example, anthropologists or microbiologists. However, botanists have their moments, particularly when collecting new species. The great botanists of the eighteenth and nineteenth centuries risked their lives in collecting and bringing back species, which we now take for granted, and Robert Brown was one of these adventurers, a young Scot who accompanied Sir Joseph Banks to New Holland.

It was not, however, for his adventurous lifestyle that Brown is remembered but for his startling observation of the movements of pollen grains on a microscope slide. He noted that the pollen grains were in perpetual agitated motion, without purpose or direction but full of energy. This motion, called Brownian motion, arises from the movement of molecules, and Brownian motion is the term that has been applied to much of healthcare, including many screening programmes, which have in the past been marked more by the amount of energy and activity than by a clear sense of direction or positive achievement. Copyright © 2001 John Wiley & Sons, Ltd.
Effect of solvents on radiation‐induced grafting of styrene onto fluorinated polymer films
Authors: Nasef Mohamed Mahmoud
Published: August 2002

The effect of solvents on radiation‐induced grafting of styrene onto commercial fluorinated polymer films such as poly(tetrafluoroethylene) (PTFE), poly(tetrafluoroethylene‐co‐hexafluoropropylene) (FEP) and poly(tetrafluoroethylene‐co‐perfluorovinyl ether) (PFA) was investigated by a simultaneous irradiation technique. Three solvents, ie methanol, benzene and dichloromethane, were used to dilute styrene under various irradiation doses, dose rates and monomer concentrations. The effect of addition of mineral and organic acids on the degree of grafting in the presence of the three solvents was also studied. The degree of grafting was found to be strongly dependent upon the type of solvent and composition of the monomer/solvent mixture. Dilution of styrene with dichloromethane in various grafting conditions was found to enhance dramatically the degree of grafting compared with other solvents, and the maximum degree of grafting was achieved at a monomer/solvent mixture having a composition of 60:40 (v/v). The formation of polystyrene grafts in the three fluorinated films was verified using FTIR spectrometry.

© 2001 Society of Chemical Industry
Damage to rigid‐particle‐filled polymer under cyclic tension
Authors: Bai Shu‐Lin , Liu Zong‐De , Ju Yang
Published: August 2002

The effect of particle volume fraction, strain rate and interfacial bonding strength on the damage to a glass bead‐filled high density polyethylene composite was studied experimentally by means of cyclic tension tests. Although the volume fraction of the glass beads varies from 5% to 25%, the materials studied are always sensitive to the strain rate, reflected by an increase of the modulus with strain rates changing from 10−3 s−1to 10−5 s−1. The damage evolution is a function of the applied far‐field strain, but is also strongly influenced by the particle volume fraction, strain rate and interfacial bonding strength. Strong interfacial adhesion can postpone the initiation of damage and cause a lower level of damage than that occuring with weak adhesion under a given strain. For the studied materials with interfacial debonding taking place, the higher the volume fraction of the glass beads, the greater the number of microcracks formed at the interface. The effect of strain rate on the damage may be related to the effect of loading time, ie low strain rate favours damage development. The residual strain is a function of far‐field strain and also depends on the strain rate and residual deformation of microvoids formed at two poles of the particle.

© 2001 Society of Chemical Industry
Influence of annealing treatment on the electrical conductivity of low density polyethylene
Authors: Boudou L , Guastavino J , Zouzou N , Vega J Martinez
Published: August 2002

The results obtained with films of a low density polyethylene subjected to variations in temperature from ambient to 60 °C and in an applied field from low values of around 1 V µm−1to high values (about 50 V µm−1) are presented. To identify the probable conduction mechanism in such films, a model based on the proposition of Nath and Perlman is investigated which takes into account the effects of space charge and Poole field‐assisted detrapping. We observe a relatively good agreement in measurements of current as a function of voltage and temperature. This allows us to evaluate a parameter related to trap characteristics (density, energy level, trap‐site separation, etc). Complementary measurements by differential scanning calorimetry show that the structure of the films is modified by temperature variations within the range used to study the conduction mechanism. These structural changes are then correlated with the experimental parameter obtained from Nath's model.

© 2001 Society of Chemical Industry
Synthesis, antitumour and DNA replication activities of polymers containing vinyl‐(5‐fluorouracil)‐ethanoate
Authors: Kang Nam‐In , Lee Sun‐Mi , Maeda Mizuo , Ha Chang‐Sik , Cho Won‐Jei
Published: August 2002

A new monomer, vinyl‐(5‐fluorouracil)‐ethanoate (VFUE), was synthesized by reaction of 5‐fluorouracil (5‐FU) and vinyl iodoacetate. The homopolymer of VFUE and its copolymers with acrylic acid (A, A) and maleic anhydride (MAH) were prepared by photopolymerization. The synthesized VFUE and polymers were identified by FTIR, 1H NMR and 13C NMR spectroscopies. The contents of VFUE unit in poly(VFUE‐co‐AA) and poly(VFUE‐co‐MAH) were 21 mol% and 16 mol%, respectively. The number average molecular weights of the polymers determined by gel permeation chromatography were in the range 9600–17900 g mol−1. The in vitro cytotoxicities of the samples against a normal cell line decreased as follows: 5‐FU > VFUE > poly(VFUE) > poly(VFUE‐co‐AA) > poly(VFUE‐co‐MAH). The in vivo antitumour activities of the polymers against Balb/C mice bearing the sarcoma 180 tumour cells were greater than those of 5‐FU at all concentrations. The inhibition of simian virus 40 DNA replication by the samples was much greater than that of the control.

© 2002 Society of Chemical Industry
Part 5. Influence of additives containing heteroatoms on the reactivity of butyl acrylate
Authors: Patacz Colette , Coqueret Xavier
Published: August 2002

The radiation‐induced polymerization of n‐butyl acrylate (nBuA) in the presence of small amounts of organic compounds containing heteroatoms has been investigated to evaluate the tentative explanations proposed to account for the differences in initiation rate observed between tripropyleneglycol diacrylate (TPGDA) and hexanediol diacrylate (HDDA), when subjected to electron‐beam (EB) polymerization. The progress of monomer conversion as a function of increasing dose was monitored by transmission infrared spectroscopy applied to thin films submitted to incremental exposure to EB radiation. Miscible organic additives expected to favour hydrogen abstraction, or free radical generation as a consequence of easy carbon–halogen bond scission, were thus introduced in nBuA at a concentration of 2 wt%. The kinetic changes were examined at low monomer conversion. The presence of di‐n‐butyloxide, diisopropyloxide or diisopropylsulfide was shown not noticeably to affect the conversion–dose dependence for EB‐irradiated nBuA. n‐Butyl chloride or bromide caused a noticeable reduction of nBuA reactivity; this was even greater for the iodide at the same 2 wt% concentration. n‐Butanol (nBuOH) was shown to sensitize nBuA consumption when present at a low concentration (2 wt%), but the enhancement of the polymerization rate was not as high for a larger nBuOH content (10 wt%). These results are discussed in the light of the radical anion mechanism for the radiation‐initiated polymerization of acrylate monomers. The absence of a significant sensitizing effect from additives known to enhance free‐radical formation supports the minor contribution of homolytic bond scission to the initiation mechanism. The observed effects of nBuOH at low concentration, indicate that trace amounts of protonic contaminants can exert a strong influence on the efficiency of initiation by the radical‐anion mechanism.

© 2001 Society of Chemical Industry
Effect of internal donors in propylene polymerization analyzed with the two‐site model
Authors: Shimozawa Kenichi , Saito Masayoshi , Kataoka Takuo , Chûjô Riichirô
Published: August 2002

The effect of internal donors of Ziegler‐Natta catalyst on stereoregularity in propylene polymerization was analyzed with the aid of the two‐site model analysis system. The amount of internal donor and that of external donor were varied. The probability in the selection of d (or l) monad in asymmetric site is contributed by both the amount of internal donor and that of external donor. With respect to the fraction of asymmetric site, the two‐site model enabled us to conceive that the new kinds of active centres are generated in specific cases where external donor is believed to be replacing weaker internal donor during polymerization. The effect of hydrogen concentration during polymerization is also discussed.

© 2002 Society of Chemical Industry.
Plasma surface modification of silica and its effect on properties of styrene–butadiene rubber compound
Authors: Nah Changwoon , Huh Mong‐Young , Rhee John M , Yoon Tae‐Ho
Published: August 2002

The effects of surface modification of silicas by plasma‐polymerization coating, together with modification using a silane coupling agent for a comparison on the dispersion and physical properties of styrene–butadiene rubber (SBR) are reported. The chemical compositions of the plasma‐polymerization coating were characterized using FTIR and Auger spectrometer and it was found that the plasma coating was composed of CC and CH bonds. The surface modification of silica by either plasma polymerization or silane greatly improved the dispersion of silica particles in SBR vulcanizates. The plasma‐polymerization modification of silica improved the tensile modulus of SBR vulcanizates without deterioration of important basic properties such as tensile strength and elongation at break.

© 2002 Society of Chemical Industry
Analysis of Ge junctions for GaInP/GaAs/Ge three‐junction solar cells†
Authors: Friedman D. J. , Olson J. M.
Published: August 2002

We study Ge solar cells with epitaxial GaInP windows for application as the third junction of GaInP/GaAs/Ge three‐junction solar cells. We demonstrate Ge junctions with open‐circuit voltages above 230 mV, fill factors above 65%, and internal quantum efficiencies of ∼90%. By varying separately the base and emitter contributions to the junction dark current, we deduce the factors limiting the performance of this device, and we project the improvement to the device performance that may be obtainable if key limiting factors such as the emitter surface‐recombination velocity can be mitigated. Published in 2001 by John Wiley & Sons, Ltd.
Experience with solar home systems in developing countries: a review
Authors: Nieuwenhout F. D. J. , van Dijk A. , Lasschuit P. E. , van Roekel G. , van Dijk V. A. P. , Hirsch D. , Arriaza H. , Hankins M. , Sharma B. D. , Wade H.
Published: August 2002

Solar energy is widely perceived as a promising technology for electricity generation in remote locations in developing countries. It is estimated that 1.3 million solar home systems had been installed by early 2000. An estimated one‐third of installed systems were backed by foreign donor support in government programmes and two‐thirds supplied by commercial dealers. The estimated growth in the deployment of solar lanterns is less than for SHS. One out of every 100 households that gain access to electricity in developing countries uses solar power. In spite of these successes, doubts have arisen about the effectiveness and suitability of small PV systems for rural development. Many organisational, financial and technical problems appear to present difficulties. A literature survey has been conducted to make an inventory of experience with solar PV applications for households in developing countries. The main finding is that an adequate service infrastructure is required to make projects viable. Household choice in system sizes is often too restricted in donor‐funded projects. Smaller systems sold for cash can be a good alternative to credit systems by offering to increased affordability. Gaps in existing knowledge have been identified, which could be overcome by field monitoring programmes. Copyright © 2001 John Wiley & Sons, Ltd.
Mass production technology for multicrystalline Si solar cells
Authors: Shirasawa Katsuhiko
Published: August 2002

Worldwide shipments of PV modules in the last 10 years show an increase of about 20% per year; shipments were 277 MW in 2000. About 80% of modules are made from crystalline silicon. Shipments of multicrystalline silicon (mc‐Si) modules have shown substantial increase. The PV market may be expected to increase by the development of low‐cost, and high‐technology multicrystalline silicon solar cells. This paper reviews recent progress in mass production technologies of mc‐Si solar cells. Copyright © 2002 John Wiley & Sons, Ltd.
Construct validity of the learning behavior scale with an independent sample of students
Authors: Worrell Frank C. , Vandiver Beverly J. , Watkins Marley W.
Published: August 2002

In this study, the factor structure of the Learning Behavior Scale (LBS; McDermott, Green, Francis, & Stott, 1999) was examined in an independent sample of 257 elementary school students. The LBS is a 29‐item, four‐factor scale on which teachers rate students' positive and negative learning behaviors. The results indicated that the internal consistency of the total LBS scores and the scores on two subscales (Competence Motivation and Attitude Toward Learning) were high enough for individual decision making, whereas the reliability estimates of scores on the Attention/Persistence and Strategy/Flexibility subscales were appropriate only for research or screening purposes. Factor analyses extracted factors similar to three of the factors on the LBS (Competence Motivation, Attitude Toward Learning, and Strategy/Flexibility), and suggested that the fourth factor (Attention/Persistence) may benefit from additional study. In general, the results indicate that the LBS may be a useful tool for examining students' learning behaviors. © 2001 John Wiley & Sons, Inc.
Sexual interest in children, child sexual abuse, and psychological sequelae for children
Authors: Bromberg Daniel S. , Johnson Blair T.
Published: August 2002

This article reviews the literature on sexual victimization of minors and the role of school psychologists in assessing and intervening with sexually abused minors. Although estimates of child sexual abuse prevalence differ widely owing to disclosure biases and the definitions that researchers have used in studying it, it is clear that child sexual abuse is a serious public problem. Also troubling is the extent to which “normal” adults, especially males, exhibit sexual interest in children, suggesting that a substantial number may be at risk for victimizing minors; fortunately, a variety of inhibitory mechanisms prevent most adults from committing this crime. Although victims typically suffer from sexual abuse, surprisingly, some evidence suggests that victims of sexual abuse can exhibit neutral or even positive outcomes, a controversial finding that has numerous possible explanations. Tragically, childhood sexual abuse may lead the victim to become an abuser later in life, sometimes while still a minor. We suggest directions for future research. © 2001 John Wiley & Sons, Inc.
Do dendritic amphiphiles self‐assemble in water? A Fourier transform pulse‐gradient spin‐echo NMR study
Authors: Menger Fredric M. , Peresypkin Andrey V. , Wu Shaoxiong
Published: August 2002

Amphiphilic poly(amidoamine) (PAMAM) dendrimers were synthesized having an average of 7–46 hydrophobic chains of varying lengths (C10–C14) attached to the periphery of 64 amine groups. The synthesis was performed in three steps: (1) protection of a desired number of amines with BOC groups; (2) reaction of the remaining amine groups with long‐chain acid chlorides; and (3) deprotection from the BOC groups to produce the amphiphilic dendrimers as HCl salts. The behavior of the dendrimers in aqueous media was examined by pulse‐gradient spin‐echo (FT‐PGSE) NMR and dynamic light scattering. Self‐diffusion data on dendrimers with 22 or fewer chains, along with dynamic light scattering on concentrations of ≤16 wt%, gave no indication of dendrimer–dendrimer self‐assembly via hydrocarbon chains exposed on the dendrimer surface. It is concluded that dendrimers with 7–22 chains, each having 10–14 carbons, behave as unimolecular entities with chains coiled largely within the dendrimer periphery. Only when the number of chains becomes very large (ca ≥34) are chains forced externally where they can promote hydrophobically induced self‐assembly. Monomeric dendrimers possessing the full range of functional polarity have great potential in enzyme modeling. Copyright © 2001 John Wiley & Sons, Ltd.
Sequence dependence of oxidation of some repeating pentapeptide sequences of elastin with electrolytically generated Mn(III): synthesis, kinetics and mechanistic study
Authors: Gowda D. Channe , Gowda B. K. Kempe , Rangappa K. S.
Published: August 2002

The repeating sequence of elastin, valylprolylglycylvalylglycine (VPGVG), its permutation pentamer glycylvalylglycylvalylproline (GVGVP), and its more hydrophobic pentamer glycylphenylalanylglycylvalylproline (GFGVP) were synthesized by classical solution‐phase methods and characterized. The kinetics of the oxidation of these pentapeptides (PP) by Mn(III) was studied in the presence of sulphate ions in acidic medium at 25 °C. The reaction was followed spectrophotometrically at λmax = 500 nm. A first‐order dependence of rate on both [Mn(III)] and [PP] was observed. The rate is independent of concentration of the reduction product, Mn(II) and hydrogen ions. Effects of varying dielectric constant of the medium and addition of anions such as sulphate, chloride and perchlorate were studied. Activation parameters were evaluated using Arrhenius and Eyring plots. The oxidation products were isolated and characterized. A mechanism involving the reaction of PP with Mn(III) in the rate‐limiting step is suggested. An apparent correlation was noted between the rate of oxidation and the hydrophobicity of these sequences where increased hydrophobicity results in an increased rate of oxidation. Further, it was observed that the pentamers with Pro as C‐terminus are more susceptible to oxidation than the pentamer with Gly as C‐terminus. Copyright © 2001 John Wiley & Sons, Ltd.
Formation and polymorphic phase transitions of crystalline inclusion compounds between 2,2′‐bis(9‐hydroxy‐9‐fluorenyl)biphenyl host and acetone guest
Authors: Ibragimov Bakhtiyar T. , Beketov Kayrat M. , Weber Edwin , Seidel Jürgen , Sumarna Omay , Makhkamov Kabul K. , Köhnke Kurt
Published: August 2002

The 2,2′‐bis(9‐hydroxy‐9‐fluorenyl)biphenyl host compound (1) was found to form various crystalline inclusion compounds with acetone depending on the crystallization conditions or on the method of preparation (inclusion of acetone vapour, co‐crystallization from solution). In order to understand and control the formation of these pseudopolymorphic phases regarding potential uses, single crystals of the existing phases (two 1:2 and one 1:1 compound) were prepared, their structures were solved by single‐crystal x‐ray diffraction (XRD) analysis and the desolvation and phase transformations were studied using simultaneous thermogravimetry–differential scanning calorimetry (TG–DSC) and variable‐temperature powder XRD. The results explain the inclusion and desolvation behaviour and also clarify the observed, apparently accidental formation of a 1:1 or 1:2 inclusion compound at ambient temperature. Copyright © 2001 John Wiley & Sons, Ltd.
Study of the decarboxylation mechanism of fluorobenzoic acids by strong N‐bases
Authors: Gierczyk Błażej , Wojciechowski Grzegorz , Brzezinski Bogumił , Grech Eugeniusz , Schroeder Grzegorz
Published: August 2002

The kinetics of the decarboxylation reactions of pentafluorobenzoic and tetrafluorobenzoic acids by various N‐bases were studied using 19F NMR spectroscopy. The rate constants of these reactions are dependent on the structure of the fluorinated acid and the pKa values of the N‐bases. Pentafluorobenzoic acid is decarboxylated about two orders of magnitude faster than tetrafluorobenzoic acid. With increasing pKa values of the protonated N‐bases these reactions became much slower. These results suggested that the rate‐determining step of the studied reactions is the attack of the conjugated acid (protonated N‐base) on carboxylate anion. Copyright © 2001 John Wiley & Sons, Ltd.
New silanization coating for DNA fragment analysis by capillary electrophoresis
Authors: Jung Ho Jin , Bae Young Chan
Published: August 2002

We propose a new coating technique for fused silica capillaries using silanization with trimethylchlorosilane and diethylamine as a mediating agent in DNA separation using capillary electrophoresis. The proposed coating technique is simple and stable at a high pH. Capillaries coated by the new preparation method give excellent reproducibility for DNA fragment analysis with a good relative standard deviation of less than 0.7% for 150 runs and good stability at pH 8.2. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1405–1420, 2002
Effect of the tail‐group length and degree of polymerization on the order parameter of side‐chain liquid‐crystalline polymethacrylates containing phenylbenzoate mesogenic groups
Authors: Barmatov E. B.
Published: August 2002

The orientation of the side‐chain liquid‐crystalline polymers (LCP) containing phenylbenzoate mesogenic groups in the magnetic field was examined with 2H NMR spectroscopy. The influence of the degree of polymerization as well as the length of the methylene tail group (n = 1–4) have been established. The decrease of the order parameter S of the LCPs with an increased length of the tail group was found. The order parameter S of LCPs does not depend on the degree of polymerization. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2044–2048, 2002
Synthesis of multicyclic and grafted polystyrenes
Authors: Lepoittevin Bénédicte , Hemery Patrick
Published: August 2002

Well‐defined multicyclic polystyrenes are prepared in two steps. The first step is the preparation of a cyclic difunctional polystyrene by the reaction of α,ω‐dilithiopolystyrene chains with 1,3‐bis(phenylethenyl)benzene. Then, this product is covalently grafted to poly(chloromethylstyrene) chains leading to the formation of a high molar mass product containing linear and cyclic parts. As a model reaction and to optimize the previous reaction, a study of coupling of the linear difunctional model polystyrene with poly(chloromethylstyrene) is performed leading to grafted polystyrene. The grafted products are analyzed by size‐exclusion chromatography, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry, and liquid chromatography at the exclusion‐adsorption transition point. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2723–2730, 2001
Incorporation of a photochromic hinge in a rodlike polypeptide and its influence on dielectric and optical properties
Authors: Williams Alveda J. , Gupta Vinay K.
Published: August 2002

A hinged, photoresponsive polypeptide (PAzP) was prepared and the effect of the photochromic hinge on the dielectric and photoisomerization behavior of the polymer in solution was probed. Polymerization of N‐carboxyanhydride of γ‐benzyl‐L‐glutamate was carried out with two different bifunctional photochromic amine initiators: di[(mercaptoethylamine)‐methylpropanamide]azobenzene (DMMPAB) and diaminoazobenzene (DAAB). Careful structural comparison of the polymers revealed that the basicity of the initiator plays a key role in determining the shape and structure of the polymer. Specifically, the use of a novel initiator DMMPAB prepared by the addition of flexible aliphatic amine substituents onto DAAB resulted in a hinged polymer (PAzP1), in which a single photochromic hinge was located within the polymer chain (Mw ∼ 36 kDa). In contrast, direct initiation with DAAB resulted in a polymer (PAzP2) in which the photochromic moiety was preferentially near the terminus of the polymer chain (Mw ∼ 21 kDa) and the polymer possessed a significant degree of asymmetry. Dielectric spectroscopy revealed that, in spite of a higher molecular weight, PAzP1 had a lower rotational relaxation time (2.72 μs) in solution than that of PAzP2 (4.41 μs). The residual dipole moment for the hinged PAzP1 was also smaller than that observed for PAzP2. The hinged polypeptide PAzP1 prepared from DMMPAB showed uniform photoisomerization between cis and trans states. However, the presence of flexible aliphatic amine substituents on DMMPAB caused the rate of isomerization of PAzP1 to be similar to the initiator DMMPAB. Optical characterization revealed that heterogeneity in the structure of PAzP2 was manifested as nonuniform rates of photoisomerization and thermal relaxation. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2759–2773, 2001
High‐pressure rheology and viscoelastic scaling predictions of polymer melts containing liquid and supercritical carbon dioxide
Authors: Royer Joseph R. , DeSimone Joseph M. , Khan Saad A.
Published: August 2002

High‐pressure rheological behavior of polymer melts containing dissolved carbon dioxide (CO2) at concentrations up to 6 wt % were investigated using a high‐pressure extrusion slit die rheometer. In particular, the steady shear viscosity of poly(methyl methacrylate), polypropylene, low‐density polyethylene, and poly(vinylidene fluoride) with dissolved CO2were measured for shear rates ranging from 1 to 500 s−1and under pressure conditions up to 30 MPa. The viscosity of all samples revealed a reduction in the presence of CO2with its extent dependent on CO2concentration, pressure, and the polymer used. Two types of viscoelastic scaling models were developed to predict the effects of both CO2concentration and pressure on the viscosity of the polymer melts. The first approach utilized a set of equations analogous to the Williams–Landel–Ferry equation for melts between the glass‐transition temperature (Tg) andTg+ 100 °C, whereas the second approach used equations of the Arrhenius form for melts more than 100 °C aboveTg. The combination of these traditional viscoelastic scaling models with predictions forTgdepression by a diluent (Chow model) were used to estimate the observed effects of dissolved CO2on polymer melt rheology. In this approach, the only parameters involved are physical properties of the pure polymer melt that are either available in the existing literature or can be measured under atmospheric conditions in the absence of CO2. The ability of the proposed scaling models to accurately predict the viscosity of polymer melts with dissolved high‐pressure CO2were examined for each of the polymer systems. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 3055–3066, 2001
Methanol vapor‐induced morphology and current–voltage characteristic changes in a cast‐coated nafion film/interdigitated microarray electrode
Authors: Umeda Minoru , Ojima Hiroyuki , Mohamedi Mohamed , Uchida Isamu
Published: August 2002

Methanol vapor‐induced membranous changes in a cast‐coated Nafion thin film were studied through current–voltage (I–V) characteristics with an interdigitated microarray (IDA) electrode and atomic force microscopy (AFM). The obtained I–V curves showed that the as‐prepared Nafion film was stable under humidified nitrogen gas; however, the I–V profile dramatically changed with exposure to methanol vapor. Next, the morphology of the film was compared before and after methanol exposure with AFM images. On the basis of our observations, we found that the as‐prepared film had an irregularly complicated microstructure, whereas the structure became homogeneous in appearance after 30 min of exposure to methanol gas. The alternating‐current conductivity data, showing almost the same magnitude before and after exposure, strongly suggested that the I–V profile shift was based on a change in an electrode reaction mechanism induced by a change in the junction at the Nafion/IDA electrode interface. Furthermore, the methanol vapor‐pre‐exposed Nafion was stable for further exposure to methanol vapor, water vapor, or both. With the stabilized film used in combination with the IDA electrode, a reversible change in the magnitude of the current was observed when the methanol/water vapor ratio was varied. This indicated that the electrode reaction had good reproducibility after the treatment. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1103–1109, 2002
Clay‐reinforced polyamide: Preferential orientation of the montmorillonite sheets and the polyamide crystalline lamellae
Authors: Varlot K. , Reynaud E. , Kloppfer M. H. , Vigier G. , Varlet J.
Published: August 2002

Intercalated and exfoliated nanocomposites were prepared by the extrusion and injection of polyamide‐6 and highly swollen or slightly swollen montmorillonite, respectively. The microstructure of pure compounds was characterized. The basal spacing was more homogeneous in swollen montmorillonite than in nontreated montmorillonite. This was attributed to the presence of a surfactant. Surfactant crystallites were observed in swollen montmorillonite and in the nanocomposites. Their distribution is discussed. The nanocomposites exhibited anisotropic properties attributed to the orientation of the montmorillonite sheets. The preferential orientation of the montmorillonite sheets was studied in detail by small‐angle X‐ray scattering (SAXS). It was found to be related to the injection direction. An average distance between two sheets was also measured from the SAXS spectra. The crystallographic state of the polyamide matrix was then analyzed. The orientation of the polymer lamellae relative to the montmorillonite sheets is discussed. The orientation of the montmorillonite sheets and the polyamide lamellae is expected to play a major role in the mechanical properties of nanocomposites. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1360–1370, 2001
Morphology and electrical breakdown properties of LDPE‐polypropylene copolymer blends
Authors: Zhang Chao , Mori Tatsuo , Mizutani Teruyoshi , Ishioka Mitsugu , Cheng Yonghong
Published: August 2002

In this study, the specimens of low‐density polyethylene (LDPE) and blend polymers of LDPE and a random copolymer of ethylene and propylene were prepared by the blowing process and T‐die method. The differences in electrical breakdown properties and morphology between the specimens made by the two different methods were studied. It was found that the specimen made by the T‐die method had a higher electrical breakdown strength than the specimen made by the blowing process, except for the DC breakdown strength in some cases at 30 °C. The morphology of the specimens was investigated by means of the measurements of thermal shrinkage, infrared dichroism, and X‐ray diffraction. The specimen made by the T‐die method has a stronger orientation in both the crystalline and amorphous phases than the specimen made by the blowing process. The difference in morphology is supposed to be correlated with the difference in electrical breakdown properties between the specimens made by the two different methods. It was concluded that the electrical breakdown properties are strongly affected by the orientation of chains in the specimen. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1741–1748, 2001
Prediction of polyimide materials with high glass‐transition temperatures
Authors: Liang Taining , Yang Xiaozhen , Zhang Xiangyu
Published: August 2002

The prediction of chemical structures that possess higher glass‐transition temperatures (Tg's) is crucial for designing polyimides. Because of a lack of suitable parameters, several estimation methods cannot be used for this purpose. In this study, therefore, we used molecular dynamic simulation with the DREIDING II force field to predict Tg's for polyimides. Simulated results indicated a good agreement with experimental observations. A barrier analysis of the bridging bonds between moieties along the main‐chain backbone showed a correlation between Tg and the barrier height. This proved to be helpful in a preliminary selection before the molecular dynamic simulation for accelerating the process of research and development on new polyimides. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2243–2251, 2001
Considerations of psychosocial illness phase in cancer survival
Authors: Clipp Elizabeth C. , Hollis Donna R. , Cohen Harvey J.
Published: August 2002

Rarely are biomedical, clinical and psychosocial data considered simultaneously as influences on cancer patient outcomes. This study utilized medical record and interview data from 152 adult cancer patients with various tumor types in a model of survival estimation. Predictors included disease stage of the neoplasm (TNM stage), clinical functioning of the patient (Karnofsky performance status), and psychosocial demands of the disease course (psychosocial illness phase). Psychosocial illness phase captures developmental time phases of illness (i.e. ‘crisis’, ‘early chronic’, ‘late chronic’ and ‘terminal’), essentially locating patients along the disease course relative to treatment and treatment response. The analysis utilized the Kaplan–Meier (product‐limit) method to estimate stratum specific survival functions. Model comparisons employed the differences in the likelihood ratio chi‐squares between nested models, and Cox proportional hazard models assisted in explaining the effects of the predictors on survival times. Results indicate that psychosocial illness phase makes an independent contribution to survival time estimation (p<0.05) when all three dimensions are considered simultaneously. Copyright © 2001 John Wiley & Sons, Ltd.
Improvements of lung function in cystic fibrosis
Authors: Tauber Erich , Eichler Irmgard , Gartner Christian , Halmerbauer Gerhard , Götz Manfred , Rath Regina , Wojnarowski Claudia , Frischer Thomas
Published: August 2002

Improved care for patients with cystic fibrosis (CF) has led to their improved survival. We analyzed retrospectively whether improvements in lung function (LF) could be detected in our CF patients over the decade 1980–1990. In 72 patients, 153 LF measurements were performed in their first year of life (1980–1991), and then 189 LF measurements were performed again in 60 of those patients during their sixth year of life (1987–1997). Regression analysis was performed on LF parameters at age 6 years.

When adjusting for weight, height, gender, and LF in the first year of life, the date of subsequent measurement was positively associated with FEV1 (P < 0.01) and MEF50% (P < 0.05) and negatively with FRCpleth (P < 0.05).

The proposed model predicts a child's FEV1 at age 6 to be 75% of predicted if born in 1980, but 108% of predicted when born in 1990. Improved CF care is the most likely explanation for this observation. Pediatr Pulmonol. 2002; 33:263–268. © 2002 Wiley‐Liss, Inc.
Irreversible airway obstruction in childhood asthma? A clinician's viewpoint
Authors: König Peter
Published: August 2002

Even though childhood asthma is assumed to comprise reversible airway obstruction, some children develop irreversible airway obstruction (not reversed by a bronchodilator or corticosteroids); this may be due to inflammation that has caused remodeling. Lately, it has been claimed that in the absence of treatment with inhaled corticosteroids, most patients will develop progressive irreversible obstruction. Several studies culminating with the Childhood Asthma Management Program (CAMP) study, which was the first randomized placebo‐controlled prospective long‐term study designed to test for irreversible obstruction, did not show the development of such progressive irreversible obstruction. Nevertheless, deterioration in pulmonary function does occur in some patients, probably due to inadequate anti‐inflammatory treatment, and possibly also due to maintenance adrenergic treatment. Most previous studies concentrated on forced expiratory volume in 1 sec (FEV1), a test assessing mostly large airway obstruction. More studies are needed to investigate the presence of small airway obstruction. Pediatr Pulmonol. 2002; 33:307‐310. © 2002 Wiley‐Liss, Inc.