bluuebunny/crossref_metadata_2025_split huggingface dataset:
The sizes of molecules—revisited
Authors: Marcus Yizhak 
Published: June 2003

AbstractThe size of molecules, be it their volume, surface area or linear extent, is an important quantity in many fields of chemistry. Molecules are often tacitly or explicitly treated as if they were spheres, so that a diameter can be assigned to them. However, the molecules of many kinds of substances are rather cylindrical, being rod‐ or disk‐shaped, so that two linear dimensions are needed for their description. The collision diameters obtainable from experimental data on gases and vapors or diameters obtained from the molar volume or the application of an expression for the interaction potential in liquids, e.g. the Lennard–Jones potential, are explored as ways to yield information on molecular sizes. The ratio of the van der Waals volume and surface area is related to a simple expression derived solely from the composition of the molecules for various types of molecular shapes. These approaches were applied to a database of 350 mainly liquid (but also some gaseous and solid) organic (and a few inorganic) substances. Copyright © 2003 John Wiley & Sons, Ltd.
Transport properties of organic vapors in nanocomposites of isotactic polypropylene
Authors: Gorrasi Giuliana , Tammaro Loredana , Tortora Mariarosaria , Vittoria Vittoria , Kaempfer Dirk , Reichert Peter , Mülhaupt Rolf 
Published: June 2003

AbstractIsotactic polypropylene nanocomposites were obtained by the melt blending of polypropylene‐graft‐maleic anhydride and organophilic layered silicate (OLS) consisting of synthetic fluorohectorite modified by cation exchange with protonated octadecylamine. The composition of the inorganic clay was varied between 2.5 and 10 wt %, and films of the composites were obtained via hot‐press molding. X‐ray analysis showed that nanocomposites in which silicate layers were either delaminated or ordered as in an intercalated structure were obtained. The elastic modulus of the samples was higher than that of the pure polymer over a wide temperature range and increased with increasing inorganic content. The transport properties, sorption and diffusion, were measured for two organic vapors, dichloromethane and n‐pentane. For both vapors, the sorption was not very different from that of the pure polymer, whereas the zero‐concentration diffusion parameter strongly decreased with increasing OLS content. Therefore, the permeability, that is, the product of sorption and diffusion, decreased for both vapors as a result of the decreased value of the diffusion parameter. The decrease was higher for the less interacting n‐pentane. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1798–1805, 2003
The association between social support, intrusive thoughts, avoidance, and adjustment following an experimental cancer treatment
Authors: Devine Danielle , Parker Patricia A. , Fouladi Rachel T. , Cohen Lorenzo 
Published: June 2003

AbstractA social‐cognitive processing model was used to examine the association of social support with intrusive thoughts and avoidance in predicting adjustment in 53 patients receiving an experimental vaccine for the treatment of either metastatic melanoma (n=24) or metastatic renal cell cancer (n=29). Social support, intrusive thoughts/avoidance, psychological distress and quality of life were assessed on the day of the first treatment, on the day of the final treatment, and 1 month after the end of treatment during a routine follow‐up visit. Social support at the beginning of treatment was negatively associated with psychological distress and positively associated with mental health quality of life (QOL) 1 month after treatment, and these associations were mediated by intrusive thoughts/avoidance at the end of treatment. There was also an interaction between social support and intrusive thoughts/avoidance at the beginning of treatment in predicting both psychological distress and mental health QOL 1 month after treatment. Specifically, for patients with lower levels of support, greater intrusive thoughts/avoidance was associated with greater psychological distress and poorer mental health QOL 1 month after treatment. However, there was no association between intrusive thoughts/avoidance and adjustment in patients with high levels of social support. These results suggest that social support buffers the negative association between intrusive thoughts/avoidance and psychological adjustment. Overall, the results are consistent with a social‐cognitive processing model of post‐trauma reactions among cancer patients. Our results highlight the need to assess patients' perceived support and to further develop and assess the benefits of interventions to increase patients' supportive networks and to facilitate cognitive processing of the cancer experience. Copyright © 2003 John Wiley & Sons, Ltd.
The fertility‐ and menopause‐related information needs of younger women with a diagnosis of breast cancer: A qualitative study
Authors: Thewes Belinda , Meiser Bettina , Rickard Judy , Friedlander Michael 
Published: June 2003

AbstractThe use of chemotherapy and endocrine therapies in the treatment of pre‐menopausal women carries with it reproductive and gynaecological implications which younger women may find both unpleasant and discordant with plans for childbearing. This study aims to investigate the fertility‐ and menopause‐related information needs of younger women with a diagnosis of early breast cancer. A retrospective qualitative methodology was chosen. Twenty‐four women aged between 26 and 45 years at diagnosis participated in focus group interviews and telephone interviews. Many women thought that the information they had received in the past about fertility and menopausal symptoms was either insufficient or unavailable. Some women felt that, while information on fertility and menopause issues had not been paramount at the time of diagnosis, it became increasingly important after diagnosis. Participants spoke about the need to revisit or review fertility‐ and menopause‐related information with their doctors during the course of treatment. Many women believed that information about fertility should be given prior to or during treatment decision‐making, and that information related to the management of menopausal symptoms should be delivered during or after treatment when menopausal symptoms begin. Consultation with a fertility and/or menopause specialist‐rated as the most preferred mode of receiving fertility‐ and menopause‐related information. Clinical implications are drawn from the results of this study to assist clinicians and researchers to improve their communication with younger patients about the fertility‐ and menopause‐related side effects of breast cancer treatment. Copyright © 2003 John Wiley & Sons, Ltd.
Measuring self‐care independence in children with cystic fibrosis: The self‐care independence scale (SCIS)
Authors: Patton Susana R. , Graham Julie L. , Varlotta Laurie , Holsclaw Douglas 
Published: June 2003

AbstractWe describe the development and psychometric properties of a survey tool designed to evaluate children's level of independence in their cystic fibrosis (CF) treatment. Children's self‐care autonomy is important to measure and may have a direct effect on children's active involvement in their treatment and their adherence. Existing instruments that evaluate children's independence in their CF treatment fail to yield practical information that can help research and patient management. The Self‐Care Independence Scale (SCIS) is a 44‐item questionnaire that is completed by parents. The SCIS was completed by the parents of 76 patients with CF (ages 4–17 years). Youths completed two structured interviews, which screened patients for average or higher cognitive functioning (an inclusion criterion) and measured their CF treatment knowledge. Parents completed two other self‐report questionnaires. Results indicated that the SCIS has acceptable internal consistency and good test‐retest reliability. The construct validity of the SCIS was supported by positive correlations between patient age, number of years since diagnosis, and SCIS total scores. The concurrent validity of the SCIS was supported by correlations between a measure of nonillness‐specific dependence and a measure of patient self‐care knowledge. Children's SCIS total scores per age group are presented. This study supports the SCIS as a psychometrically sound measure of self‐care independence in CF. This measure has several uses. For example, the SCIS may be a screening tool for adolescents who are preparing to transition to adult CF centers and who will need to assume more independence in their self‐care. The SCIS may also be used to evaluate educational programs that promote self‐care knowledge and skill in children with CF. Pediatr Pulmonol. 2003; 36:123–130. © 2003 Wiley‐Liss, Inc.
Characterization of successful and failed autoresuscitation in human infants, including those dying of SIDS
Authors: Sridhar Raghunathan , Thach Bradley T. , Kelly Dorothy H. , Henslee Judith A. 
Published: June 2003

AbstractOur purpose was to identify and further characterize physiologic mechanisms relevant to autoresuscitation from hypoxic apnea in infants dying suddenly and unexpectedly. We studied cardiorespiratory recordings of 24 infants (age range, 0.8–21 months) who died suddenly while being monitored at home. These recordings were analyzed for features indicated by studies in animal models to be characteristic of hypoxic gasping, and of recovery from bradycardia and apnea associated with gasping (e.g., autoresuscitation). Findings in 5 infants diagnosed as having sudden infant death syndrome were compared with 6 non‐SIDS infants whose deaths resulted from other conditions. Additionally, we studied 15 healthy infants during sleep, using home monitor and other respiratory recording techniques, in order to obtain comparison data. We found in recordings from 23 of 24 subjects that hypoxic gasps with characteristic features occurred immediately preceding death. A unique pattern of complex, closely spaced gasps (“double” or “triple” gasps) was present in many subjects. Evidence of partially successful autoresuscitation closely following one or more gasps occurred in 11 subjects, while another 4 had evidence of complete autoresuscitation with return of normal heart rate and resolution of apnea on one or more occasions. Significant differences between SIDS infants and those dying from other causes included increased occurrence of complex gasps and decreased occurrence of partial or complete autoresuscitation in the SIDS infants. The non‐SIDS cases were different from the SIDS cases in that only one had “double” gasps (n = 7), while none had “triple” gasps, as compared with 4 out of 5 SIDS cases with these patterns (P < 0.05, chi‐square). Also, in contrast with the SIDS cases, more of the cases with specific postmortem diagnoses had evidence of partial (5 out of 6 cases) or complete (1 out of 6 cases) autoresuscitation (P < 0.05, chi‐square). We conclude that partial or complete autoresuscitation by gasping is not uncommon in moribund infants during the first year of life. Failure of autoresuscitation mechanisms other than failure to initiate gasping may be characteristic of infants dying of SIDS. Some SIDS infants appear to be different from infants dying with other diagnoses with respect to efficacy and characteristics of hypoxic gasping. Pediatr Pulmonol. 2003; 36:113–122. © 2003 Wiley‐Liss, Inc.
Mirth‐triggered asthma: Is laughter really the best medicine?
Authors: Liangas Georgios , Morton John R. , Henry Richard L. 
Published: June 2003

AbstractMirthful emotions such as laughter and excitement are unrecognized but perhaps important triggers of asthma. Our study aimed to explore the prevalence, mechanisms, and associations of mirth‐triggered asthma (MTA) in children. Our MTA prevalence questionnaire was given to 285 children who presented to the Emergency Department of Sydney Children's Hospital (SCH) with an acute episode of asthma. Our MTA profile questionnaire study was a cross‐sectional study of 541 children with asthma. The parents completed a questionnaire regarding their child's asthma. In our laughter diary study, diary cards were given to the parents of 21 children with asthma. The diary required details regarding the mirthful stimulus, symptoms of asthma, and recording of peak expiratory flow (PEF) measurements. Of the selected cohort, 31.9% had mirth‐triggered asthma. In the cross‐sectional study, mirth‐triggered asthma was more common: with increasing age (P = 0.02); in those who in the last 3 months had taken more doses of salbutamol (P = 0.005), and who had more wheeze, nocturnal symptoms, and early morning symptoms (P < 0.0005); and in those who reported exercise‐induced asthma (P < 0.0005). Laughter was more commonly reported as a trigger than excitement; cough was the most prominent symptom; and symptoms mostly occurred within 2 min of the mirthful stimulus. In the laughter diary study, 59 of 130 recorded events described symptoms of asthma. Mirth while watching a film led to PEF of 73% of baseline, compared with 81% for mirth with exertional play, and 95% for mirth with nonexertional play (P = 0.01). Mirth‐triggered asthma is common, and is an indicator of suboptimal asthma control. Pediatr Pulmonol. 2003; 36:107–112. © 2003 Wiley‐Liss, Inc.
Rotating D‐branes and O‐planes
Authors: Angelantonj C. 
Published: June 2003

AbstractWe review orientifold constructions in the presence of magnetic backgrounds both in the open and closed sectors. Generically, the resulting orientifold models have a nice geometric description in terms of rotated D‐branes and/or O‐planes. In the case of multiple magnetic backgrounds, some amount of supersymmetry is recovered if the magnetic fields are suitably chosen and part of the original D‐branes and/or O‐planes are transmuted into new ones.
Unitary quantum field theory on the noncommutative Minkowski space
Authors: Bahns D. 
Published: June 2003

AbstractThis is an exposition of joint work with S. Doplicher, K. Fredenhagen, and Gh. Piacitelli [1]. The violation of unitarity found in quantum field theory on noncommutative spacetimes in the context of the so‐called modified Feynman rules is linked to the notion of time ordering implicitly used in the assumption that perturbation theory may be done solely in terms of Feynman propagators. Two alternative approaches which do not entail a violation of unitarity are sketched. An outlook upon our more recent work is given.
Strings on plane waves: an introduction
Authors: Berenstein D. 
Published: June 2003

AbstractThis article is a brief introduction to different aspects of string theory on maximally supersymmetric plane waves in ten dimensions. The article touches on the following aspects: quantization of free strings on the plane wave background, the plane wave as a Penrose limit and it's relation to AdS / CFT; and finally the causal structure of the plane wave and holography.
On a gauge invariant description of soliton dynamics
Authors: de Wit B. , Käppeli J. 
Published: June 2003

AbstractWe present important elements of a gauge and diffeomorphism invariant formulation of the moduli space approximation to soliton dynamics. We argue that explicit velocity‐dependent modifications are determined entirely from gauge and diffeomorphism invariance. We illustrate the formalism for the case of a Yang‐Mills theory on a curved spacetime background.
Non‐commutative field theories beyond perturbation theory
Authors: Bietenholz W. , Hofheinz F. , Nishimura J. 
Published: June 2003

AbstractWe investigate two models in non‐commutative (NC) field theory by means of Monte Carlo simulations. Even if we start from the Euclidean lattice formulation, such simulations are only feasible after mapping the systems onto dimensionally reduced matrix models. Using this technique, we measure Wilson loops in 2d NC gauge theory of rank 1. It turns out that they are non‐perturbatively renormalizable, and the phase follows an Aharonov‐Bohm effect if we identify θ = 1/B. Next we study the 3d λ ϕ4 model with two NC coordinates, where we present new results for the correlators and the dispersion relation. We further reveal the explicit phase diagram. The ordered regime splits into a uniform and a striped phase, as it was qualitatively conjectured before. We also confirm the recent observation by Ambjø rn and Catterall that such stripes occur even in d = 2, although they imply the spontaneous breaking of translation symmetry. However, in d = 3 and d = 2 we observe only patterns of two stripes to be stable in the range of parameters investigated.
Strings in singular time‐dependent backgrounds
Authors: Giveon A. , Rabinovici E. , Sever A. 
Published: June 2003

AbstractWe review the construction of time‐dependent backgrounds with space‐like singularities. We mainly consider exact CFT backgrounds. The algebraic and geometric aspects of these backgrounds are discussed. Physical issues, results and difficulties associated with such systems are reviewed. Finally, we present some new results: a two dimensional cosmology in the presence of an Abelian gauge field described within a family of ${{SL(2)\times U(1)} \over {U(1)\times Z}}$ quotient CFTs.
Production of black holes in TeV‐scale gravity
Authors: Ringwald A. 
Published: June 2003

AbstractCopious production of microscopic black holes is one of the least model‐dependent predictions of TeV‐scale gravity scenarios. We review the arguments behind this assertion and discuss opportunities to track the striking associated signatures in the near future. These include searches at neutrino telescopes, such as AMANDA and RICE, at cosmic ray air shower facilities, such as the Pierre Auger Observatory, and at colliders, such as the Large Hadron Collider.
Form‐field gauge symmetry in M‐theory
Authors: Kalkkinen J. , Stelle K.S. 
Published: June 2003

AbstractWe show how to cast an interacting system of M‐branes into manifestly gauge‐invariant form using an arrangement of higher‐dimensional Dirac surfaces. Classical M‐theory has a cohomologically nontrivial and noncommutative set of gauge symmetries when written using a “doubled” formalism containing 3‐form and 6‐form gauge fields. We show how the arrangement of Dirac surfaces allows an integral subgroup of these symmetries to be preserved at the quantum level. The proper context for discussing these large gauge transformations is relative cohomology, in which the 3‐form transformation parameters become exact when restricted to the five‐brane worldvolume. This structure yields the correct lattice of M‐theory brane charges.
Quantum Liouville theory versus quantized Teichmüller spaces
Authors: Teschner J. 
Published: June 2003

AbstractThis note announces the proof of a conjecture of H. Verlinde, according to which the spaces of Liouville conformal blocks and the Hilbert spaces from the quantization of the Teichmüller spaces of Riemann surfaces carry equivalent representations of the mapping class group. This provides a basis for the geometrical interpretation of quantum Liouville theory in its relation to quantized spaces of Riemann surfaces.
pp‐wave string models with interacting light‐cone actions
Authors: Tseytlin A.A. 
Published: June 2003

AbstractWe consider pp‐wave backgrounds for which superstring action written in light‐cone gauge have the form of an interacting 2‐d theory. All pp‐wave solutions supported by non‐constant H3 or Fp fields are exact type II superstring solutions to all orders in α′. The corresponding light‐cone gauge Green‐Schwarz actions are non‐linear in bosons but always quadratic in fermions, and describe UV finite (but, in general, non‐supersymmetric) 2‐d theories. We consider a specific example where the pp‐wave F3 background is parametrized by an arbitrary holomorphic function of one complex bosonic coordinate.
Criminal outcomes and costs of treatment services for injecting and non-injecting heroin users: evidence from a national prospective cohort survey
Authors: Healey Andrew , Knapp Martin , Marsden John , Gossop Michael , Stewart Duncan 
Published: June 2003

Objectives: To assess the incremental cost-effectiveness of drug addiction treatment programmes provided in the UK by the National Health Service and not-for-profit agencies in terms of crime-related outcomes. All costs and crime-related outcomes were implicitly evaluated relative to a 'no treatment' alternative. Methods: Longitudinal observational data on a national sample of heroin addicts referred to addiction treatment services throughout England were re-analysed. Predictions from a Poisson random-effects model were used to estimate the incremental effectiveness and cost-effectiveness of treatment programmes. Interaction variables were used to assess whether the injecting of heroin on entry to treatment had an impact on cost-effectiveness. Results: The findings rejected the null hypothesis that increasing time in treatment (and therefore treatment cost) has no mean crime prevention effect on clients referred for community-based methadone treatment, treatment delivered within specialist drug dependency units and residential rehabilitation programmes ( P < 0.05). However, the size of the cost per unit of effect based on model predictions was sensitive to the exclusion of a small group of outlying observations. The interaction between client injecting status and time in treatment was found to be statistically significant ( P < 0.05), with an estimated reduction in treatment cost-effectiveness across all treatment programmes for clients who reported injecting drugs at treatment intake. Conclusions: Whilst the analyses did not include an evaluation of the effect of treatment programmes on client health and quality of life and stopped short of providing a social weighting for the predicted reduction in crimes, they do offer a useful starting point for establishing the cost-effectiveness of treating heroin addiction. The onus is on public decision-makers to decide whether the predicted reductions in crime are worth the opportunity costs of investing extra resources in a major expansion of treatment services.
General practitioners' uptake of clinical practice guidelines: a qualitative study
Authors: Harrison Stephen , Dowswell George , Wright John , Russell Ian 
Published: June 2003

Objective: To explain recent rapid audited change in the uptake of locally implemented, evidence-based clinical guidelines for asthma and angina in primary care. Methods: A case study of primary care in two matched, adjacent districts in Northern England, focusing on a stratified random sample of 49 general practitioners (GPs) from eight primary care groups. Data were collected from three cycles of mainly qualitative interviews carried out at six-monthly intervals, before and after the dissemination of local guidelines and after audit data were gathered. Interviews examined attitudes, awareness and impact of locally disseminated asthma and angina guidelines and the subsequent audit. Audit data on guideline uptake were also available from a parallel study. Results: The rapid increase in guideline uptake observed in both intervention and control groups was not explained by individual practitioners or practice factors. The findings are attributed to GPs' awareness of policies for evidence-based medicine, of new health service institutions and of the clinical governance activities of primary care groups. Behaviour change reflects GPs' decisions about what to record in case notes as well as their clinical decisions, so that findings may reflect changing perceptions about accountability rather than about preferred treatment regimes. Conclusions: Guideline production and dissemination is best seen in the broader context of policy change. Studies of guideline implementation should report before and after data and incorporate significant qualitative components in order to identify important contextual factors.