bluuebunny/crossref_metadata_2025_split huggingface dataset:
Curing and thermal behavior of diglycidyl ether of bisphenol A in the presence of a mixture of amines
Authors: Khurana Parveen , Narula A. K. , Choudhary Veena 
Published: September 2003

AbstractThe curing behavior of diglycidyl ether of bisphenol A (DGEBA) was investigated by differential scanning calorimetry with mixtures of silicon‐containing amide–amines and diaminodiphenyl sulfone (DDS). Silicon‐containing amide–amines were prepared by the reaction of 2.5 mol of 4,4′‐diaminodiphenyl ether (E), 4,4′‐diaminodiphenyl methane (M), 3,3′‐diaminodiphenyl sulfone (mS), 4,4′‐diaminodiphenyl sulfone (pS), bis(3‐aminophenyl) methyl phosphine oxide (B), or tris(3‐aminophenyl) phosphine oxide (T) with 1 mol of bis(4‐chlorobenzoyl) dimethyl silane. Mixtures of the amide–amines and DDS at ratios of 0:1, 0.25:0.75, 0.5:0.5, 0.75:0.25, and 1:0 were used to investigate the curing behavior of DGEBA. A single exotherm was observed on curing with a mixture of amide–amine and DDS. This clearly shows that the mixture participated in the cocuring reaction. The peak exotherm temperature depended on the structure and the molar ratio of amide–amines. With all of the amide–amines and DDS, a significant decrease in the kick‐off temperature of the curing exotherm was observed on the incorporation of a 0.25 molar fraction of amide–amines. Thus, with the mixture, the curing temperatures were reduced and were lowest for ether‐containing amide‐amines and highest for methylene‐containing amide–amines. The char yield was almost similar in the samples cured with amide–amines (E, pS, or mS) or DDS. The char yield was higher than for either of the constituents when a mixture was used. A synergistic behavior was observed when a mixture of E, M, mS, or pS and DDS was used, whereas mixture of B or T and DDS showed antigonism in the char yield. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1739–1747, 2003
Electropolymerization of pyrrole and characterization of the obtained polymer films
Authors: Sayyah S. M. , Abd El‐Rehim S. S. , El‐Deeb M. M. 
Published: September 2003

AbstractElectrochemical oxidative polymerization of pyrrole on platinum electrode in acid medium was carried out. Different reaction parameters were investigated such as current density, acid concentration, monomer concentration, and temperature with duration of time. The orders of the electropolymerization reaction were found to be 1.3, 1.26, and 1.2 with respect to current density, acid concentration, and monomer concentration, respectively. The apparent activation energy was found to be 38.3 kJ mol−1. The obtained polymer films were characterized by 1H‐NMR, elemental analysis, thermogravimetric analysis, and cyclic voltammetry. The mechanism of the electrochemical polymerization reaction was also discussed. The surface morphology of the obtained polymer film was characterized by X‐ray diffraction and scanning electron microscopy. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1783–1792, 2003
Effect of the synthesis route on the structure and properties of polyurethane/nitrokonjac glucomannan semi‐interpenetrating polymer networks
Authors: Gao Shanjun , Zhang Lina , Huang Qilin 
Published: September 2003

AbstractWith a synthesis route differing from previous methods, novel semi‐interpenetrating polymer networks (semi‐IPNs), coded UNK‐II, were synthesized by the initial mixing of nitrokonjac glucomannan (NKGM) with castor oil in butanone and the subsequent addition of toluene diisocyanate (TDI) to begin the polymerization reaction in the presence of 1,4‐butanediol (BD) as a chain extender at 60°C. The results from dynamic mechanical analysis, differential scanning calorimetry, and ultraviolet spectroscopy indicated that a certain degree of microphase separation occurred between soft and hard segments of polyurethane (PU) in the UNK‐II sheets. The α‐transition temperature, glass‐transition temperature, heating capacity, and tensile strength increased with an increase in the NKGM content, and this suggested an interaction between PU and NKGM in the UNK‐II sheets. In a previous method, semi‐IPN materials (PUNK) were synthesized by the polymerization reaction between castor oil and TDI, and then this PU prepolymer was mixed with NKGM and cured in the presence of BD as a chain extender. The PUNK sheets had relatively good miscibility and mechanical properties. However, for UNK‐II sheets prepared by the method reported in this work, NKGM mainly played a role in reinforcement. When the NKGM content was less than 10%, the UNK‐II sheets exhibited good miscibility, tensile strength (26–28 MPa), and breaking elongation (130–140%), similar to those of PUNK materials. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1948–1954, 2003
Objective assessment of technical skills of surgical trainees in Hong Kong
Authors: Bann S , Kwok K-F , Lo C-Y , Darzi A , Wong J 
Published: September 2003

Abstract

Background
The need for assessment of technical skills is well recognized and objective methods of assessment are currently under investigation in the UK. The applicability of these assessment tools to trainees with a different training background in another country was examined.

Methods
Six bench-top models for basic surgical trainees (BSTs) and eight for higher surgical trainees (HSTs) (five in common) were assessed for construct validity in 70 subjects. Objective assessment methods included motion analysis using the Imperial College Surgical Assessment Device, Objective Structured Assessment of Technical Skills and Minimally Invasive Surgical Trainer in Virtual Reality.

Results
All models shared between BSTs and HSTs exhibited construct validity (range P = 0·050 to P &lt; 0·001). Of the three modules for HSTs alone, only one gave significant results (small bowel anastomosis; P = 0·005). Reasons for this were sought.

Conclusion
The methods of objective technical skills assessment of trainees in the UK are applicable to those in Hong Kong. Their use should be promoted and the tracking of skills development encouraged.
Relationship between gene polymorphisms of mannose‐binding lectin (MBL) and two molecular forms of MBL
Authors: Terai Itaru , Kobayashi Kunihiko , Matsushita Masanao , Miyakawa Hiroshi , Mafune Naoki , Kikuta Hideaki 
Published: September 2003

AbstractMannose‐binding lectin (MBL) activates complement through MBL‐associated serine proteases (MASP). A deficiency in MBL due to mutations at exon 1 of the human MBL gene is reported to cause vulnerability to infection. We examined sera of known MBL genotype by gel filtration and assessed their elution patterns using an ELISA for MBL and identified two MBL forms, a high‐molecular‐mass form and a lower‐molecular‐mass form. By the identification of either or both forms in individual sera, three types of patterns emerged: type 1 consisted of a high‐molecular form; type 2, of a low‐molecular form; and type 3, of both forms. Types 1, 2 and 3 corresponded, respectively, to a wild type (A/A), a homozygous mutation at codon 54 (B/B) and their heterozygote (A/B). One exception was a heterozygous LXPA/LYPB phenotype that exhibited the type‐2 pattern. Binding to mannan and MASP‐1/3 occurred exclusively with the high‐molecular form. An apparent MBL deficiency does not in fact representa deficiency in MBL molecules but rather the presence of circulating oligomeric mutant MBL with impaired function.
Synthesis of Scopin Acetate and 6,7‐Didehydrohyoscyamin. Intramolecular Phenylsulfenylation of a Nonactivated Methylene Group of Ethyl N‐Demethyl‐3‐O‐(phenylthio)tropine‐N‐carboxylate
Authors: Petrović Goran B. , Saičić Radomir N. , Čeković Živorad M. 
Published: September 2003

AbstractThe synthesis of scopin acetate (6b) and 6,7‐didehydrohyoscyamine (17) was achieved by using tropine (5) as the starting compound. Formal (phenylthio)‐radical transfer to the nonactivated 6‐position of ethyl N‐demethyl‐3‐O‐(phenylthio)tropine‐N‐carboxylate (9) by irradiation in the presence of hexabutyldistannane is a key step of this synthetic approach, involving ethyl 6,7‐didehydro‐N‐demethyltropine‐N‐carboxylate (15) as a synthetic intermediate (Schemes 3 and 5). The reaction of 9 with tributylstannane in the presence of ethyl acrylate, as a radicophilic olefin, involves Michael‐type alkylation at C(6) of the tropine skeleton affording ethyl N‐demethyl‐N‐(ethoxycarbonyl)tropine‐6‐propanoate (18) (Scheme 6).
The Counterion Effect on the Assembly of Coordination Networks of Cationic (η3‐Allyl)palladium Complexes Containing 3,5‐Dimethyl‐4‐nitro‐1H‐pyrazole
Authors: Cano Mercedes , Heras José V. , Gallego M. Luz , Perles Josefina , Ruiz‐Valero Caridad , Pinilla Elena , Torres M. Rosario 
Published: September 2003

AbstractTwo new (η3‐allyl)palladium complexes containing the ligand 3,5‐dimethyl‐4‐nitro‐1H‐pyrazole (Hdmnpz) were synthesized and characterized as [Pd(η3‐C3H5)(Hdmnpz)2]BF4 (1) and [Pd(η3‐C3H5)(Hdmnpz)2]NO3 (2). The structures of these compounds were determined by single‐crystal X‐ray diffraction to evaluate the intermolecular assembly. Each complex exhibits similar coordination behavior consistent with cationic entities comprised of two pyrazole ligands coordinated with the [Pd(η3‐C3H5)]+ fragment in an almost square‐planar coordination geometry. In 1, the cationic entities are propagated through strong intermolecular H‐bonds formed between the pyrazole NH groups and BF$\rm{_{4}^{-}}$ ions in one‐dimensional polymer chains along the a axis. These chains are extended into two‐dimensional sheet networks via bifurcated H‐bonds. New intermolecular interactions established between NO2 and Me substituents at the pyrazole ligand of neighboring sheets give rise to a three‐dimensional network. By contrast, compound 2 presents molecular cyclic dimers formed through NH⋅⋅⋅O H‐bonds between two NO$\rm{_{3}^{-}}$ counterions and the pyrazole NH groups of two cationic entities. The dimers are also connected to each other through CH⋅⋅⋅O H‐bonds between the remaining O‐atom of each NO$\rm{_{3}^{-}}$ ion and the allyl CH2 H‐atom. Those interactions expand in a layer which lies parallel to the face (101).
An Unexpected Formation of a 14‐Membered Cyclodepsipeptide
Authors: Iliev Boyan , Linden Anthony , Heimgartner Heinz 
Published: September 2003

AbstractThe treatment of diluted solutions of the hydroxy diamides 6a and 6b in toluene with HCl gas at 100° gave the dimeric, 14‐membered cyclodepsipeptide 10 in up to 72% yield (Scheme 3). The same product was formed from the linear dimer of 6b, the depsipeptide 11, under the same conditions (cf. Scheme 4). All attempts to prepare the cyclic seven‐membered monomer 9, starting with different precursors and using different lactonization methods failed, and 10 was the only product which was isolated (cf. Scheme 6). For example, the reaction of the ester 20 with NaH in toluene at 80° led exclusively to the cyclodimer 10. On the other hand, the base‐catalyzed cyclization of the hydroxy diester 22, which is the ‘O‐analogue' of 20, yielded neither the seven‐membered dilactone, nor the 14‐membered tetralactone, but only the known trimer 23 and tetramer 24 of 2,2‐dimethylpropano‐3‐lactone (cf. Scheme 7).
Synthesis and Reactivity of Photochromic 2H‐Chromenes Based on 3‐Carboxylated Coumarins
Authors: Cerqueira Nuno M. F. S. A. , Rodrigues Lígia M. , Oliveira‐Campos Ana M. F. , Melo de Carvalho Luís H. , Coelho Paulo J. , Dubest Roger , Aubard Jean , Samat André , Guglielmetti Robert 
Published: September 2003

AbstractNew photochromic 2H‐chromenes (=2H‐1‐benzopyrans) including a 3‐carboxylated coumarin nucleus were synthesized from hydroxycoumarins, and, in one case, the corresponding trimethoxysilylcarboxamide was prepared. The photochromic behavior was studied under flash‐photolysis conditions. The introduction of electron‐withdrawing substituents in this position of the coumarin nucleus led to a global and significant bathochromic shift in the spectra of the open forms and to an interesting intensification in the colorability.
Gene expression profiling following chronic NMDA receptor blockade‐induced learning deficits in rats
Authors: O'Donnell James , Stemmelin Jeanne , Nitta Atsumi , Brouillette Jonathan , Quirion Rémi 
Published: September 2003

AbstractAcute treatments with MK‐801, a noncompetitive antagonist of the NMDA glutamate receptor, induce spatial memory deficits in rodents. In the present study, we developed a low‐dose chronic MK‐801 treatment regimen that induced persistent learning deficits (determined by the Morris water maze task) after administration of the drug (0.2 mg/kg) every 12 h for 14 days. To determine the impact of such a treatment, changes in mRNA expression were investigated in the hippocampi and striata of treated animals using a cDNA membrane array followed by Western blots. Genes whose expression levels were found to be most altered included preprolactin (downregulated) and mitogen‐activated protein kinase (MAP kinase 1; upregulated) in the hippocampus, and acyl‐CoA synthetase (downregulated) and apolipoprotein D (upregulated) in the striatum. Furthermore, MAP kinase 1 and proteosome subunit β precursor was found to meet selection criteria for upregulation in both the hippocampus and striatum. Among other genes found to be most changed in the hippocampus were protein kinase C β I and II, protein tyrosine phosphatase 1β, neuropilin I and II, adenosine receptor A1, and metabotropic glutamate receptor 2/3. The impact of some gene expression alterations on their corresponding protein levels was studied next. In the hippocampus, protein kinase C β I and II, protein tyrosine phosphatase, neuropilin I and II, adenosine receptor A, metabotropic glutamate receptor 2/3, and in the striatum phosphatidyl inositol 4 kinase, mitogen‐activated protein kinase 1, adenylyl cyclase II, dopamine receptors 1A and 2, and cytochrome C oxidase subunit Va gene and protein expression levels were found to be highly correlated. These results suggest the potential involvement of several genes and proteins in the neuropharmacological effects of MK‐801 and possibly the persisting cognitive deficits induced by this repeated drug treatment. Synapse 50:171–180, 2003. © 2003 Wiley‐Liss, Inc.
The Familial Cancer Program of the Vermont Cancer Center: Development of a Cancer Genetics Program in a Rural Area
Authors: McKinnon Wendy C. , Guttmacher Alan E. , Greenblatt Marc S. , Compas Bruce E. , May Sandy , Cutler Roy E. , Yandell David W. 
Published: September 2003

AbstractIn response to many scientific discoveries linking cancer in certain families to inherited factors, the Vermont Cancer Center established the Familial Cancer Program (FCP) in December 1993. This multifaceted program combines the expertise of clinicians and researchers in many disciplines, including genetics, oncology, psychology, and molecular biology. The program's goals are identification of families in its region with excess cancer, provision of clinical services to such families, and use of research protocols when available and appropriate. This article describes the experience of setting up a familial cancer program in a rural area and discusses both successes and challenges in such an endeavor.
Toward a Model Informed Consent Process for BRCA1 Testing: A Qualitative Assessment of Women's Attitudes
Authors: Bernhardt Barbara A. , Geller Gail , Strauss Misha , Helzlsouer Kathy J. , Stefanek Michael , Wilcox Patti M. , Holtzman Neil A. 
Published: September 2003

AbstractAs an initial part of a project to develop a model informed consent process for BRCA1 testing, we conducted a series of focus groups. At the groups, women initially expressed great interest in testing, but their interest diminished after learning more. If offered testing, women would most want to learn about test accuracy, practical details of testing, and management options if the result was positive. Perceived benefits of testing included gaining information leading to risk reduction, relief of uncertainty, more responsible parenting, and assisting in research. Perceived risks included the discomfort and cost of the testing process itself, and anxiety after a positive result. The risk of possible insurance discrimination was rarely mentioned spontaneously. Many women would want their providers to make recommendations, rather than be nondirective about testing. We observed that women vary greatly in their informational and counseling needs, and suggest that the informed consent process should be individualized, taking into account a woman's perception and her preferences for how testing decisions should be made.
Toward a Critical Community Psychological Perspective on Unemployment and Mental Health Research
Authors: Fryer David , Fagan Rose 
Published: September 2003

AbstractPsychological research has established that unemployment causes widespread psychological distress and ill health in communities but, arguably, little of this research is truly community psychological. In this paper we sketch out a critical community psychological perspective and use it to contribute to understanding of the role of psychosocial aspects of income in the experience and mental health of employed and unemployed members of low‐income families in a severely deprived community context; to the development of innovative participatory methodology, and to promote the interests of impoverished unemployed people through the research process as well as through the research outcome.
Predictors of Mortality in 2,249 Nonagenarians—The Danish 1905‐Cohort Survey
Authors: Nybo Hanne , Petersen Hans Chr. , Gaist David , Jeune Bernard , Andersen Kjeld , McGue Matt , Vaupel James W. , Christensen Kaare 
Published: September 2003

Objectives: To elucidate whether well‐known predictions of mortality are reduced or even reversed, or whether mortality is a stochastic process in the oldest old.Design: A multidimensional survey of the Danish 1905 cohort conducted in 1998 with follow‐up of vital status after 15 months.Setting: Denmark.Participants: All Danes born in 1905, irrespective of physical and mental status were approached. Two thousand two hundred sixty‐two persons of 3,600 participated in this survey.Measurements: Professional interviewers collected data concerning sociodemographic factors, smoking, alcohol consumption, body mass index, physical and cognitive performance, and health during a visit at the participant's residency. Cox regression models were used to evaluate predictors of mortality.Results: Five hundred seventy‐nine (25.7%) of the 2,249 participants eligible for the analysis died during the 15 months follow‐up. Multivariate analyses showed that marital status, education, smoking, obesity, consumption of alcohol, and number of self‐reported diseases were not associated with mortality. Disability and cognitive impairment were significant risk factors in men and women. In addition poor self‐rated health was associated with an increase in mortality in women.Conclusion: In the oldest old, several known predictors of mortality, such as sociodemographic factors, smoking, and obesity, have lost their importance, but a high disability level, poor physical and cognitive performance, and self‐rated health (women only), predict mortality, which shows that mortality in the oldest old is not a stochastic process.
Vision and Driving Self‐Restriction in Older Adults
Authors: West Catherine G. , Gildengorin Ginny , Haegerstrom‐Portnoy Gunilla , Lott Lori A. , Schneck Marilyn E. , Brabyn John A. 
Published: September 2003

Objectives: To assess driving self‐restriction (vision related and nonvision related) in relation to vision test performance of older adults.Design: Cross‐sectional study.Setting: Population‐based cohort of community‐dwelling older adults.Participants: Six hundred twenty‐nine current drivers aged 55 and older had driving behavior, health, and physical function assessed and vision function tested in 1993–95.Measurements: Self‐report of driving restriction as vision or non‐vision related and performance on a comprehensive battery of vision tests (visual acuity; contrast sensitivity; effects of illumination level, contrast, and glare on acuity; visual fields with and without attentional load; color vision; temporal sensitivity; and the effect of dim light on walking ability).Results: Demographic, health, and functional characteristics differed significantly between restrictors and nonrestrictors but not between vision‐ and nonvision‐related restrictors. Controlling for potential confounding, only vision‐related driving self‐restriction was significantly associated with reduced performance on nonstandard measures of acuity. Poor depth perception was significantly associated with restriction for both vision‐ and nonvision‐related reasons. Poor performance on attentional visual field tests, analyzed individually and in combination with standard field tests, was not associated with driving self‐restriction.Conclusion: Older adults with early changes in spatial vision function and depth perception appear to recognize their limitations and restrict their driving even if they do not acknowledge the visual impairment as the cause for restriction. Poor visual attention, a risk factor for crashes, may not be recognized. Additional studies of driving self‐restriction in relation to risk factors for crashes in older adults may help refine this strategy of reducing driving‐related injury and death.
Linezolid Compared with Eperezolid, Vancomycin, and Gentamicin in an In Vitro Model of Antimicrobial Lock Therapy for
Staphylococcus epidermidis
Central Venous Catheter-Related Biofilm Infections
Authors: Curtin John , Cormican Martin , Fleming Gerard , Keelehan John , Colleran Emer 
Published: September 2003

ABSTRACT

Central venous catheter (CVC)-related infection (CVC-RI) is a common complication of CVC use. The most common etiological agents of CVC-RI are gram-positive organisms, in particular, staphylococci. An in vitro model for the formation of biofilms by
Staphylococcus epidermidis
ATCC 35984 on polyurethane coupons in a modified Robbins device was established. Biofilm formation was confirmed by electron microscopy and was quantified by determination of viable counts. Mueller-Hinton broth was replaced with sterile physiological saline (control) or a solution of vancomycin (10 mg/ml), gentamicin (10 mg/ml), linezolid (2 mg/ml), or eperezolid (4 mg/ml). Viable counts were performed with the coupons after exposure to antimicrobials for periods of 24, 72, 168, and 240 h. The mean viable count per coupon following establishment of the biofilm was 4.6 × 10
8
CFU/coupon, and that after 14 days of exposure to physiological saline was 2.5 × 10
7
CFU/coupon. On exposure to vancomycin (10 mg/ml), the mean counts were 2.5 × 10
7
CFU/coupon at 24 h, 4.3 × 10
6
CFU/coupon at 72 h, 1.4 × 10
5
CFU/coupon at 168 h, and undetectable at 240 h. With gentamicin (10 mg/ml) the mean counts were 2.7 × 10
7
CFU/coupon at 24 h, 3.7 × 10
6
CFU/coupon at 72 h, 8.4 × 10
6
CFU/coupon at 168 h, and 6.5 × 10
6
CFU/coupon at 240 h. With linezolid at 2 mg/ml the mean counts were 7.1 × 10
5
CFU/coupon at 24 h and not detectable at 72, 168, and 240 h. With eperezolid (4 mg/ml) no viable cells were recovered after 168 h. These data suggest that linezolid (2 mg/ml) and eperezolid (4 mg/ml) achieve eradication of
S. epidermidis
biofilms more rapidly than vancomycin (10 mg/ml) and gentamicin (10 mg/ml).