bluuebunny/crossref_metadata_2025 huggingface dataset:
Curing and properties comparison of an unsaturated polyester resin, varying crosslinking reaction conditions
Authors: Jasso‐Gastinel C. F. , Vivero‐Marin J. M.
Published: November 2004

In this work four different curing modes were used to crosslink a general‐purpose unsaturated polyester resin. Styrene was used as monomer and glass fiber mat as reinforcement. The four curing modes included a traditional convection oven, a long‐wavelength infrared (IR) radiation oven, a medium‐wavelength IR radiation oven, or room temperature for an open‐curing condition without oven heating. Some samples were cured using initiator only, and others were cured combining initiator and promoter. For oven curing, chamber temperature was 85°C. For the samples, final curing conversion (using Fourier transform IR spectroscopy), as well as glass transition temperature (Tg), Young's modulus, impact strength, and Shore D hardness were measured and compared. The medium‐wavelength IR radiation oven as curing condition offered the best option for highest conversion, Tg, and mechanical properties. Polym. Compos. 25:662–666, 2004. © 2004 Society of Plastics Engineers.
People with type 2 diabetes facing the reality of starting insulin therapy: factors involved in psychological insulin resistance
Authors: Bogatean M Pop , Hâncu N
Published: November 2004

Psychological insulin resistance has drawn increasing attention, due to its multiple implications, to the patient's well‐being, and also to the overall costs of diabetes management. Exploratory studies have emphasised, as main psychological barriers, needle phobia, fear of hypoglycaemia or weight gain, or impaired patient–health care team communication. This study addresses psychological insulin resistance from the qualitative point of view. We analysed 18 people with type 2 diabetes, at the moment of initiating insulin therapy. The methodology was a qualitative one, including phenomenological analysis and content analysis of the semi‐structured interviews. The results show that the most salient contributors to psychological insulin resistance are: the mental representations (patients' personal view of reality) of the reasons for the necessity to start insulin therapy (e.g. incorrect medical decision); the perceived consequences of the treatment (e.g. social rejection); and the factors which contributed to the decision to refuse or accept the treatment (e.g. family, other people with diabetes). Other factors which contribute to the decision regarding insulin therapy are the presence of concomitant diseases and the acute discomfort generated either by hyperglycaemia or by the previous medication.

There is an increased need to study this issue in culturally sensitive settings, because of the important role played by the social environment in the adaptation to an intrusive chronic treatment. Copyright © 2004 John Wiley & Sons, Ltd.
Why do people with diabetes contact Diabetes UK for dietary advice?
Authors: Connor H , Bunn E , McGough N
Published: November 2004

A survey of 91 e‐mail enquiries to Diabetes UK showed evidence of a substantial un‐met need for better quality dietary advice, both at the time of diagnosis and during follow up. There was evidence of inadequate and inappropriate advice and of conflicting advice from different health care professionals. Many of those who were newly diagnosed were confused about what they should and should not eat.

Doctors and nurses who give dietary advice need better training in current nutritional principles. People with type 1 diabetes should be seen by a state registered dietitian within two days of diagnosis and those with type 2 diabetes within one month. All patients should be offered an annual dietetic review with a state registered dietitian and there should be provision for those who need more frequent review. Copyright © 2004 John Wiley & Sons, Ltd.
Diabetes and survival after myocardial infarction: is cardiac rehabilitation an effective secondary prevention measure?
Authors: Kirk A , Fisher M , MacIntyre P
Published: November 2004

Cardiovascular disease is the leading cause of death in people with type 2 diabetes. People with diabetes have substantially higher short‐term (30 days) and long‐term (up to 10 years) mortality rates after acute myocardial infarction, than people without diabetes. The reason behind this higher mortality rate is not completely understood. Cardiac rehabilitation post myocardial infarction has been shown to be beneficial in non‐diabetic patients in reducing both morbidity and mortality. Research investigating the effectiveness of cardiac rehabilitation for people with diabetes is much more limited. Copyright © 2004 John Wiley & Sons, Ltd.
Developing laminar morphology in higher‐viscosity‐ratio polyblends by controlling flow fields in a single‐screw extruder
Authors: Huang Han‐Xiong , Huang You‐Fa , Yang Shu‐Lin
Published: November 2004

The morphology of high‐density polyethylene (HDPE)/polyamide‐6 (PA‐6) blends with different melt‐shear‐viscosity ratios (VRs), prepared by combining a single‐screw extruder with a convergent die was studied. Two different screw geometries, metering and mixing screws, and three screw speeds, 20, 40 and 60 rpm, were evaluated to investigate their effects on the morphology of extruded ribbons. Two mixing screws with low and high shear intensity, respectively, were used. Both the geometry and speed of screw were found to have an important role in the morphological changes of the blends. In contrast to previous studies, the results shown in this work reveal that it is possible to develop a laminar structure of PA‐6 in an HDPE matrix with a VR larger than one by controlling the flow fields, through appropriately combining the type and shear intensity of the screw with its speed. A well‐developed laminar PA‐6 phase with an aspect ratio of about 100 was obtained under the optimum combination. Copyright © 2004 Society of Chemical Industry
Effect of coupling agents on rice‐husk‐filled HDPE extruded profiles
Authors: Panthapulakkal S , Sain M , Law S
Published: November 2004

Lignocellulosic composites are diversifying their applications into various fields as they can meet the requirements of the respective applications by changing the matrix, fiber resource and processing ingredients. In this research work we explored the potential of extruded rice‐husk‐filled high density polyethylene (HDPE) composite profiles for structural applications. The structure and the properties of the interface in fiber‐reinforced composites play a crucial role in determining the performance properties of the composites. An optimum degree of adhesion between the fiber and the matrix is required for efficient stress transfer from the matrix to the fiber. Generally, coupling agents are used to improve the adhesion between lignocellulosic filler and the polymer matrix in structural composite materials. In this study, four different coupling agents based on ethylene‐(acrylic ester)‐(maleic anhydride) terpolymers and ethylene‐(acrylic ester)‐(glycidyl methacrylate) terpolymers were used to enhance the performance properties of the composites. The results indicated that these coupling agents enhanced the tensile and flexural strength of the composites significantly, and the extent of the coupling effect depends on the nature of the interface formed. Incorporation of coupling agents enhanced the resistance to thermal deformation and the water absorption properties of the composite, whereas it reduced the extrusion rate significantly. Among the four coupling agents used, EGMA1—the one with a glycidyl methacrylate functional group and without any methyl acrylate pendant group on the polymer backbone—was found to be the best coupling agent for the rice‐husk‐filled HDPE composites. Copyright © 2004 Society of Chemical Industry
Synthesis and copolymerization reactions of p‐acryloyloxybenzoic acid with organotin monomers
Authors: Azab MM
Published: November 2004

p‐Acryloyloxybenzoic acid (PAB) was prepared by the reaction of p‐hydroxybenzoic acid and acryloyl chloride in the presence of triethylamine. Triphenyltin acrylate (TPTA), triphenyltin methacrylate (TPTMA), p‐acryloyloxytriphenyltin benzoate (TPTB) and triphenyltin itaconate (TPTI) monomers were prepared by the reactions of acrylic, methacrylic, p‐acryloyloxybenzoic and itaconic acids, respectively, with triphenyltin hydroxide in the presence of dicyclohexylcarbodiimide (DCCI) as a dehydrating agent. Binary copolymerizations of PAB with TPTA, TPTMA, TPTB and TPTI were performed in dimethylformamide (DMF) using 1 mol% azobisisobutyronitrile (AIBN) as initiator at 65 °C. The structures of the monomers and copolymers were investigated by IR and 1H NMR spectrometry. The composition of the copolymers was determined by tin analysis. Copolymerization parameters for each system were calculated by both the Fineman–Ross and Kelen–Tüdös methods. The monomer reactivity ratios for the four systems studied, PAB‐TPTA, PAB‐TPTMA, PAB‐TPTB and PAB‐TPTI, were found to be r1 = 0.468, r2 = 2.096; r1 = 0.435, r2 = 2.292; r1 = 0.449, r2 = 2.225 and r1 = 0.416, r2 = 4.526, respectively. The average Q and e values for the prepared organotin monomers were calculated. Copyright © 2004 Society of Chemical Industry
Copolymerization of the pair maleic anhydride–dicyclopentadiene: I. Copolymerization and post‐copolymerization at high conversion
Authors: Rusen Edina , Marculescu Bogdan , Albu Ana‐Maria , Mircea Vuluga Dumitru , Boborodea Adrian , Sorin Vasilescu Dan
Published: November 2004

The present study describes the kinetic investigation of the complex binary copolymerization system maleic anhydride (MA)—dicyclopentadiene (DCPD). All syntheses were carried out in homogeneous solution; high conversions in soluble and linear copolymer are achievable when starting from an equimolecular monomer feed. Excess of DCPD would limit the attainable conversions, while surplus of MA would induce crosslinking of the copolymers. The findings of the thorough kinetic study were sustained by structural assessment from IR and NMR spectra recorded for various copolymers, both soluble and gels. Copyright © 2004 Society of Chemical Industry
Factors affecting the degradation and drug‐release mechanism of poly(lactic acid) and poly[(lactic acid)‐co‐(glycolic acid)]
Authors: Alexis Frank
Published: November 2004

This paper reviews the most important factors affecting the degradation and drug‐release rate of bio‐erodible polymers for better control in biomedical applications. There are several factors that influence the overall rate of degradation, in addition to pH and copolymer composition. In general, polymer degradation is accelerated by greater hydrophilicity in the backbone or end groups, lesser crystallinity, lower average molecular weight, and smaller size of the finished device. At the moment, literature reflects contradictions about the role played by chemically reactive additives, crystallinity and degradation path. Factors affecting degradation and drug‐release rate are discussed in their decreasing order of importance, including intrinsic properties of polymers and processing parameters. Copyright © 2004 Society of Chemical Industry
Risk‐based maintenance (RBM): A new approach for process plant inspection and maintenance
Authors: Khan Faisal I. , Haddara Mahmoud
Published: November 2004

This paper discusses recently proposed methodology for the design of an optimum maintenance management program. The methodology is based on integrating a reliability approach and a risk assessment strategy to obtain an optimum maintenance schedule. The method is called risk‐based maintenance (RBM). First, the likely equipment failure scenarios are formulated. Out of the many likely failure scenarios, the ones that are most credible are subjected to a detailed study. Detailed consequence analysis is done for the selected scenarios. Subsequently, a fault tree analysis is performed to determine the probability of failure. Finally, risk is computed by combining the consequence analysis and the probability analysis results. The calculated risk is compared against known acceptable criteria. The frequency of maintenance tasks is obtained by minimizing the estimated risk. The proposed methodology is used to answer two questions: Which equipment should be included in a scheduled maintenance program? When should the maintenance be scheduled?

Offshore oil and gas process facilities involve hazardous chemicals (highly flammable and toxic) at extreme conditions of temperature and pressure. Proper maintenance of process equipment is one of the important activities to ensure safe and continuous operation of the facility. RBM methodology has been used to develop a detailed maintenance plan for safe and fault free operation of the facility. © 2004 American Institute of Chemical Engineers Process Saf Prog, 2004
Asymptotic degree distribution in random recursive trees
Authors: Janson Svante
Published: November 2004

The distributions of vertex degrees in random recursive trees and random plane recursive trees are shown to be asymptotically normal. Formulas are given for the asymptotic variances and covariances of the number of vertices with given outdegrees. We also give functional limit theorems for the evolution as vertices are added. The proofs use some old and new results about generalized Pólya urn models. We consider generalized Pólya urns with infinitely many types, but reduce them to the finite type case. © 2004 Wiley Periodicals, Inc. Random Struct. Alg., 2005
Integer and fractional packing of families of graphs
Authors: Yuster Raphael
Published: November 2004

Let F be a family of graphs. For a graph G, the F‐packing number, denoted νF(G), is the maximum number of pairwise edge‐disjoint elements of F in G. A function ψ from the set of elements of F in G to [0, 1] is a fractional F‐packing of G if σe∈H∈F ψ(H) ≤ 1 for each e ∈ E(G). The fractional F‐packing number, denoted νF* (G), is defined to be the maximum value of σ ψ(H) over all fractional F‐packings ψ. Our main result is that νF* (G)−νF(G) = o(|V(G)|2). Furthermore, a set of νF(G)−o(|V(G)|2) edge‐disjoint elements of F in G can be found in randomized polynomial time. For the special case F = {H0} we obtain a simpler proof of a recent difficult result of Haxell and Rödl [Combinatorica 21 (2001), 13–38] that ν* (G) − ν (G) = o(|V(G)|2). Their result can be implemented in deterministic polynomial time. We also prove that the error term o(|V(G)|2) is asymptotically tight. © 2004 Wiley Periodicals, Inc. Random Struct. Alg., 2005
Ethnic and gender differences in drinking, smoking and drug taking among adolescents in England: a self‐report school‐based survey of 15 and 16 year olds
Authors: Rodham Karen , Hawton Keith , Evans Emma , Weatherall Rosamund
Published: November 2004

Concern has been mounting about the increasing numbers of adolescents who (ab)use drugs, alcohol and cigarettes. The aim of this study was to establish the prevalence according to gender and ethnicity of drinking, smoking and drug‐use in a representative sample of 15 and 16 year olds. The sample consisted of 6020 15‐ and 16‐year‐old pupils from 41 schools in England who completed an anonymous self‐report survey.

There were clear gender and ethnic differences in self‐reported substance use. For example, more males than females reported drinking and drug taking. More females reported smoking, but males were more likely to be heavy smokers. Asian, Black and other boys and Black and Asian girls were less likely to report drinking during a typical week compared to White participants. Asian females were less likely to report smoking compared to White females. Cannabis was the most commonly used drug for both genders. Black males were more likely than White males to have used cannabis, opiates and other drugs. However, Asian females were more likely than their White counterparts to have used opiates, but were significantly less likely to have used cannabis. Asian males were more likely than White males to have used ecstasy.

The results confirm gender differences in substance use and demonstrate that there are different patterns of substance use between ethnic groups. These findings have implications for targeting prevention campaigns through the media and educational initiatives.
Median and ulnar nerve conduction in pregnancy
Authors: Eogan M. , O'Brien C. , Carolan D. , Fynes M. , O'Herlihy C.
Published: November 2004

Objective

A prospective, observational study assessed median and ulnar nerve conduction during pregnancy, to identify the optimum test for differentiating physiological effects of pregnancy from pathological carpal tunnel syndrome (CTS).

Methods

Pregnant women (n=18) and age‐ and parity‐matched non‐pregnant controls (n=13) were recruited. Symptomatic and neurophysiological evaluations were performed. Median and ulnar nerve latencies and intrapalmar latency (difference between median and ulnar nerve latencies) were computed.

Results

Median nerve distal latency is more prolonged in pregnant women compared with non‐pregnant controls. Median nerve latency is more prolonged in pregnant women with symptoms of CTS than in asymptomatic women. The difference between median and ulnar nerve conduction (normal <0.2 ms) discriminates well between symptomatic and asymptomatic pregnant women.

Conclusions

Intrapalmar latency is proposed as a useful diagnostic test for classification of carpal tunnel syndrome during pregnancy.
ARE SENIORITY PRIVILEGES UNFAIR?
Authors: GOSSERIES AXEL P.
Published: November 2004

What should maximin egalitarians think about seniority privileges? We contrast a good-specific and an all-things-considered perspective. As to the former, inertia and erasing effects of a seniority-based allocation of benefits from employment are identified, allowing us to spot the categories of workers and job-seekers made involuntarily worse off by such a practice. What matters however is to find out whether abolishing seniority privileges will bring about a society in which the all-things-considered worst off people are better off than in the seniority rule's presence. An assessment of the latter's cost-reduction potential is thus needed, enabling us to bridge a practice taking place within a firm with its impact on who the least well off members of society are likely to be. Three accounts of the profitability of seniority privileges are discussed: the “(firm specific) human capital”, the “deferred compensation” and the “knowledge transfer” ones. The respective relevance of “good-specific” and “all-things-considered” analysis is discussed. It turns out that under certain circumstances, a maximin egalitarian case for seniority privileges could be made.

Senior: Do you know that they are planning layoffs? Of course, it is only fair that they lay-off the newcomers first! After all, I have been loyal to the company for many years.

Junior: Did I choose to be a newcomer?
THE ETHICS AND ECONOMICS OF THE MINIMUM WAGE
Authors: WILKINSON T. M.
Published: November 2004

This paper develops a normative evaluation of the minimum wage in the light of recent evidence and theory about its effects. It argues that the minimum wage should be evaluated using a consequentialist criterion that gives priority to the jobs and incomes of the worst off. This criterion would be accepted by many different types of consequentialism, especially given the two major views about what the minimum wage does. One is that the minimum wage harms the jobs and incomes of the worst off and the other is that it does neither much harm nor much good. The paper then argues at length that there are no important considerations besides jobs and incomes relevant to the assessment of the minimum wage. It criticizes exploitation arguments for the minimum wage. It is not clear that the minimum wage would reduce exploitation and the paper doubts that, if it did, it would do so in a morally significant way. The paper then criticizes freedom arguments against the minimum wage by rejecting appeals to self-ownership and freedom of contract and by arguing that no freedom of significance is lost by the minimum wage that is not already taken account of in the main consequentialist criterion. The conclusion is that, at worst, the minimum wage is a mistake and, at best, something to be half-hearted about.
Heterophils isolated from chickens resistant to extra-intestinal Salmonella enteritidis infection express higher levels of pro-inflammatory cytokine mRNA following infection than heterophils from susceptible chickens
Authors: FERRO PAMELA J. , SWAGGERTY CHRISTINA L. , KAISER PETE , PEVZNER IGAL Y. , KOGUT MICHAEL H.
Published: November 2004

Previous studies showed differences in in vitro heterophil function between parental (A>B) broilers and F1 reciprocal crosses (D>C). Our objectives were to (1) determine if in vitro variations translate to differences in resistance to Salmonella enteritidis (SE) and (2) quantitate cytokine mRNA in heterophils from SE-infected chicks. One-day-old chicks were challenged and organs were cultured for SE. Chicks with efficient heterophils (A and D) were less susceptible to SE compared to chicks with inefficient heterophils (B and C). Heterophils were isolated from SE-infected chicks and cytokine mRNA expression was evaluated using quantitative real-time RT–PCR. Pro-inflammatory cytokine mRNA was up-regulated in heterophils from SE-resistant chicks compared to susceptible chicks. This is the first report to quantitate cytokine mRNA in heterophils from SE-infected chicks. These data show a relationship between in vitro heterophil function, increased pro-inflammatory cytokine mRNA expression, and increased resistance to SE in 1-day-old chicks.
Seroprevalence and force of infection of varicella-zoster virus in Luxembourg
Authors: MOSSONG J. , PUTZ L. , SCHNEIDER F.
Published: November 2004

A serological prevalence survey was carried out in Luxembourg during 2000–2001 to determine the antibody status of the Luxembourg population against vaccine-preventable infections including varicella-zoster virus (VZV). ELISA tests performed on 2679 sera indicated that 96 (3·6%) of the study population were seronegative. Age-specific seroprevalence rose rapidly from approximately 70% at age 4 years to 90% at age 6 years to 95% at age 12 years. Significant heterogeneity of seroprevalence was observed between the six different primary schools. For age groups 0–5, 6–11 and 12+ years, we estimated an annual force of infection of 0·361 [95% confidence interval (CI) 0·31–0·415)], 0·204 (95% CI 0·12–0·29) and 0·05 (95% CI 0·024–0·082) respectively. Our results indicate that transmission of VZV is highest in children below the age of 6 years and that much lower levels of VZV transmission occur in secondary schools and throughout adulthood.
Declining hepatitis A seroprevalence: a global review and analysis
Authors: JACOBSEN K. H. , KOOPMAN J. S.
Published: November 2004

Hepatitis A virus (HAV) is spread by faecal–oral contact or ingestion of contaminated food or water. Lifelong immunity is conferred by infection or vaccination, so anti-HAV seroprevalence studies can be used to indicate which populations are susceptible to infection. Seroprevalence rates are highly correlated with socioeconomic status and access to clean water and sanitation. Increasing household income, education, water quality and quantity, sanitation, and hygiene leads to decreases in HAV prevalence. Japan, Australia, New Zealand, Canada, the United States, and most European nations have low anti-HAV rates. Although anti-HAV rates remain high in most Latin American, Asian, and Middle Eastern nations, average seroprevalence rates are declining. Surveys from Africa generally indicate no significant decline in anti-HAV rates. Because the severity of illness increases with age, populations with a high proportion of susceptible adults should consider targeted vaccination programmes.
Leptospirosis among schoolchildren of the Andaman & Nicobar Islands, India: low levels of morbidity and mortality among pre-exposed children during an epidemic
Authors: VIJAYACHARI P. , SUGUNAN A. P. , MURHEKAR M. V. , SHARMA S. , SEHGAL S. C.
Published: November 2004

Leptospirosis is an important public health problem in the Andaman Islands. The disease is being increasingly reported among children and adolescents in recent times. An attempt was made to find out the level of exposure to leptospires, to estimate the incidence of infection and to identity the risk factors for acquiring infection among children. A sample of 1544 schoolchildren was selected. Presence of anti-leptospiral antibodies was tested using the microscopic agglutination test (MAT). Students were interviewed for behavioural factors. In total, 341 (221 seronegative and 120 seropositive) students were followed up clinically and serologically during a subsequent outbreak. An overall seropositivity rate of 23·6% (95% CI 21·54–25·81) was observed. Infection rate was 33·5% among seronegatives whereas re-infection rate was 16·7% among seropositives during the outbreak that occurred 1 month after the first sample collection. Morbidity and mortality were found to be higher among seronegative individuals than serpositives, More than 90% of leptospiral infections were found to be subclinical or unnoticed. The high level of exposure among the children results in high infection rates and because they have less previous exposure than adults, they do not have sufficient protection to resist clinical illness during outbreaks.
Identification of Helicobacter pylori DNA in Iranian patients with gallstones
Authors: FARSHAD SH. , ALBORZI A. , MALEK HOSSEINI S. A. , OBOODI B. , RASOULI M. , JAPONI A. , NASIRI J.
Published: November 2004

In order to identify Helicobacter in gallstones of Iranian patients with biliary disease, gallstone and bile samples from 33 patients were subjected to rapid urease test, culture and Multiplex PCR using primers based on 16s rRNA and isocitrate dehydrogenase genes for the identification of Helicobacter genus and H. pylori respectively. This PCR was also done on bile samples from 40 autopsied gallbladders with normal pathology (control group). In 18·1% of stone and 12·1% of bile samples, H. pylori DNA was detected using PCR. Rapid urease and culture tests were negative for all samples. The PCR was negative in the control group. In conclusion, H. pylori DNA was detected in stone samples of Iranian patients with gallstones but we are not sure of their viability. To clarify the clinical role of Helicobacter in gallbladder diseases, studies using accurate tests on larger patient and control groups are needed to ascertain whether this microorganism is an innocent bystander or active participant in gallstone formation.
Seroprevalence of antibody to varicella zoster virus in England and Wales in children and young adults
Authors: VYSE A. J. , GAY N. J. , HESKETH L. M. , MORGAN-CAPNER P. , MILLER E.
Published: November 2004

This is the first large-scale study to investigate the seroprevalence of varicella zoster (VZV) in the general population of England and Wales. The study focused on those aged 1–20 years, that age group in whom most infections occur. Prevalence rose rapidly with age, with 53% of children showing evidence of prior infection by the age of 5 years and most young adults having experienced infection. In addition to using a fixed cut-off recommended by the manufacturer, a mixture modelling technique was also used to define the proportion of the population seropositive in each age group. This was shown to be a more accurate approach to categorizing data from an epidemiological perspective.
Salutogenese im Alter
Authors: Wiesmann Ulrich , Wendlandt Stefanie , Hannich Hans-Joachim
Published: November 2004

Zusammenfassung: Das Kohärenzgefühl (sense of coherence, SOC) ist ein zentrales Konzept in Antonovskys Salutogenese-Modell. Diese globale Orientierung bestimmt darüber, wie effektiv eine ältere Person in der Lage ist, geeignete generalisierte Widerstandsquellen (GRRs) für die Erhaltung ihrer Gesundheit zu aktivieren. 170 aktive ältere Menschen (37 Männer) im mittleren Alter von 67 Jahren (Min-Max: 59-89) nahmen freiwillig an einer interdisziplinären Studie über gesundheitsbezogene Lebensqualität und körperliche Aktivität im Alter teil. SOC, GRRs und subjektive Gesundheitsmaße (SF-36 Summenscores und Beschwerden-Liste) wurden per Fragebogen erhoben. Das SOC kovariierte signifikant mit 11 von 13 der erhobenen GRRs; Selbstwirksamkeit, Selbstwertgefühl, Bildung und fatalistische Externalität waren signifikante Prädiktoren. Nach statistischer Kontrolle der GRRs klärte das SOC jeweils signifikant zusätzliche Varianz im psychischen Gesundheitsniveau und im Beschwerdenstatus auf; dagegen erklärten SOC und GRRs das körperliche Gesundheitsniveau nicht. Schließlich erwies sich das SOC als ein Mediator der Beziehung zwischen GRRs und dem psychischen Summenscore bzw. Beschwerdenstatus.
Top-Down Processing and Visual Reorientation Illusions in a Virtual Reality Environment
Authors: Mast Fred W. , Oman Charles M.
Published: November 2004

The role of top-down processing on the horizontal-vertical line length illusion was examined by means of an ambiguous room with dual visual verticals. In one of the test conditions, the subjects were cued to one of the two verticals and were instructed to cognitively reassign the apparent vertical to the cued orientation. When they have mentally adjusted their perception, two lines in a plus sign configuration appeared and the subjects had to evaluate which line was longer. The results showed that the line length appeared longer when it was aligned with the direction of the vertical currently perceived by the subject. This study provides a demonstration that top-down processing influences lower level visual processing mechanisms. In another test condition, the subjects had all perceptual cues available and the influence was even stronger.
Psychopharmakotherapie mit Clomipramin und Paroxetin bei jugendlichen Patientinnen mit «Anorexia nervosa» und «Depressiver Episode» - eine Pilotstudie zu Verträglichkeit, Absetzquote und therapeutischen Verlaufskriterien
Authors: Strobel Markus , Warnke Andreas , Roth Michael , Schulze Ulrike
Published: November 2004

Zusammenfassung: Fragestellung: Die Frage der Indikation und Wirkung antidepressiver Medikation bei Anorexia nervosa mit Beginn im Kindes- und Jugendalter im Verlauf stationärer Behandlung wurde bislang nur wenig untersucht. Auch mangelt es an vergleichenden Studien zu Verträglichkeit und Wirkung unterschiedlicher Thymoleptika an anorektischen Patienten dieses Altersspektrums. Gegenstand der vorliegenden Studie war ein Vergleich der Behandlungsverläufe unter Paroxetin, einem SSRI, und Clomipramin, einem trizyklischen Antidepressivum mit serotonerger Wirkkomponente. Neben Qualität und Auftretenshäufigkeit unerwünschter Wirkungen sowie Häufigkeit und Ursachen des Absetzens der Medikation galt das Interesse verschiedenen therapeutischen Verlaufskriterien. Methodik: In die retrospektive Untersuchung wurden 83 Patientinnen einbezogen, die im Zeitraum von 1988 bis 1998 erstmalig stationär in der Klinik und Poliklinik für Kinder- und Jugendpsychiatrie und Psychotherapie der Universität Würzburg behandelt wurden. Alle Patientinnen erfüllten die Kriterien einer «Anorexia nervosa» sowie «Depressiven Episode» nach ICD-10 und erhielten eine antidepressive Medikation mit Paroxetin- oder Clomipramin. Grundlage der Datenerhebung waren Basisdokumentation, multiaxiale Klassifikation sowie Verlaufs- und Abschlussberichte. Als Kriterien des Therapieerfolgs wurden die Behandlungsdauer (Tage) und der Gewichtszuwachs (kg/m2) bestimmt. Ergebnisse: Clomipramin wurde im Behandlungsverlauf signifikant häufiger als Paroxetin aufgrund unerwünschter Wirkungen sowie einer unzureichenden Beeinflussung der depressiven Zielsymptomatik abgesetzt (33,3 vs. 15,4%). Unter Paroxetin wurde ein vergleichbarer Gewichtszuwachs (2,8 vs. 2,6 kg/m2) in signifikant kürzerer Behandlungsdauer (71,9 vs. 96,5 Tage) erreicht. Schlussfolgerung: Kürzere Behandlungsdauer, raschere Gewichtszunahme, geringere Absetzquote und nicht zuletzt wirtschaftliche Überlegungen sprechen für eine im Vergleich zu Clomipramin positive Indikation von Paroxetin bei jugendlichen Patientinnen mit «Anorexia nervosa» und «Depressiver Episode». Eine prospektive Wirksamkeitsstudie ist zu fordern, um die dargelegten Ergebnisse zu prüfen.
Norbornane: An investigation into its valence electronic structure using electron momentum spectroscopy, and density functional and Green’s function theories
Authors: Knippenberg S. , Nixon K. L. , Brunger M. J. , Maddern T. , Campbell L. , Trout N. , Wang F. , Newell W. R. , Deleuze M. S. , Francois J.-P. , Winkler D. A.
Published: November 2004

We report on the results of an exhaustive study of the valence electronic structure of norbornane (C7H12), up to binding energies of 29 eV. Experimental electron momentum spectroscopy and theoretical Green’s function and density functional theory approaches were all utilized in this investigation. A stringent comparison between the electron momentum spectroscopy and theoretical orbital momentum distributions found that, among all the tested models, the combination of the Becke-Perdew functional and a polarized valence basis set of triple-ζ quality provides the best representation of the electron momentum distributions for all of the 20 valence orbitals of norbornane. This experimentally validated quantum chemistry model was then used to extract some chemically important properties of norbornane. When these calculated properties are compared to corresponding results from other independent measurements, generally good agreement is found. Green’s function calculations with the aid of the third-order algebraic diagrammatic construction scheme indicate that the orbital picture of ionization breaks down at binding energies larger than 22.5 eV. Despite this complication, they enable insights within 0.2 eV accuracy into the available ultraviolet photoemission and newly presented (e,2e) ionization spectra, except for the band associated with the 1a2−1 one-hole state, which is probably subject to rather significant vibronic coupling effects, and a band at ∼25 eV characterized by a momentum distribution of “s-type” symmetry, which Green’s function calculations fail to reproduce. We note the vicinity of the vertical double ionization threshold at ∼26 eV.
Stochastic Liouville equation simulation of multidimensional vibrational line shapes of trialanine
Authors: Jansen Thomas la Cour , Zhuang Wei , Mukamel Shaul
Published: November 2004

The line shapes detected in coherent femtosecond vibrational spectroscopies contain direct signatures of peptide conformational fluctuations through their effect on vibrational frequencies and intermode couplings. These effects are simulated in trialanine using a Green’s function solution of a stochastic Liouville equation constructed for four collective bath coordinates (two Ramachandran angles affecting the mode couplings and two diagonal energies). We find that fluctuations of the Ramachandran angles which hardly affect the linear absorption can be effectively probed by two-dimensional spectra. The signal generated at k1+k2−k3 is particularly sensitive to such fluctuations.
Optical spectra and localization of excitons in inhomogeneous helical cylindrical aggregates
Authors: Didraga Cătălin , Knoester Jasper
Published: November 2004

We study the linear optical properties of helical cylindrical molecular aggregates accounting for the effects of static diagonal disorder. Absorption, linear dichroism, and circular dichroism spectra are presented, calculated using brute force numerical simulations and a modified version of the coherent potential approximation that accounts for finite size effects by using the appropriate open boundary conditions. Excellent agreement between both approaches is found. It is also shown that the inclusion of disorder results in a better agreement between calculated and measured spectra for the chlorosomes of green bacteria as compared to our previous report, where we restricted ourselves to homogeneous cylinders [Didraga, Klugkist, and Knoester, J. Phys. Chem. B 106, 11474 (2002)]. For the excitons that govern the optical response, we also investigate the disorder-induced localization properties. By analyzing an autocorrelation function of the exciton wave function, we find a strongly anisotropic localization behavior, closely following the properties of chiral wave functions which previously have been found for homogenoeus helical cylinders [Didraga and Knoester, J. Chem. Phys. 121, 946 (2004)]. It is shown that the circular dichroism spectrum may still show a strong dependence on the cylinder length, even when the exciton wave function is localized in a region small compared to the cylinder’s size.
Doubly excited 2 1Δg state of Na2
Authors: Whang Thou-Jen , Wu Hui-Wen , Chang Ray-Yuan , Tsai Chin-Chun
Published: November 2004

The doubly excited valence (3p+3p) 2 1Δg state of Na2 is experimentally observed by using optical-optical double resonance spectroscopy. A single line Ar+ laser (a total of nine lines) was used to pump the sodium dimers from thermally populated ground state X 1Σg+ to the intermediate B 1Πu state. Then, a single mode Ti:sapphire laser was used to probe the doubly excited 2 1Δg state. Violet fluorescence emitted from the highly excited states (mainly 2 3Πg or 3 3Πg states which are transferred from 2 1Δg state via collision) to the a 3Σu+ state was monitored by a filtered photomultiplier tube (PMT). A total of 582 rovibrational levels of 2 1Δg state were observed, identified, and assigned to the vibrational and rotational quantum numbers in the range of 0⩽v⩽28 and 11⩽J⩽99, respectively. The absolute vibrational quantum number assignment was verified by comparing the totally resolved fluorescence with the calculated Franck-Condon factors between 2 1Δg state and B 1Πu state. Dunham coefficients and Rydberg-Klein-Rees potential curve were derived from these observed quantum levels. The primary molecular constants of Na2 2 1Δg state are Te=32 416.759(15) cm−1, ωe=124.8484(36) cm−1, Be=0.119 158(3) cm−1, and Re=3.508 20(5) Å.
Variational principles for stationary one- and two-fluid equilibria of axisymmetric laboratory and astrophysical plasmas
Authors: Goedbloed J. P.
Published: November 2004

It is shown that the core equations of both the magnetohydrodynamics and the two-fluid description of stationary axisymmetric equilibrium flows may be derived from variational principles in terms of the core variables of the respective descriptions. The latter replace the primitive variables because of the stream function constraints associated with axisymmetry. This yields a concise representation of stationary flows in tokamaks, accretion disks, and jets, and permits accurate numerical implementation. Since hyperbolic flows occur in both descriptions, the limitation of the variational principles to elliptic flow regimes presents an intricate problem.
The double photoionization of HCl: An ion–electron coincidence study
Authors: Alagia M. , Biondini F. , Brunetti B. G. , Candori P. , Falcinelli S. , Moix Teixidor M. , Pirani F. , Richter R. , Stranges S. , Vecchiocattivi F.
Published: November 2004

The double photoionization of HCl molecules by synchrotron radiation has been studied in the energy range between 30 and 50 eV. The HCl2+ and Cl2+ product ions have been detected by a photoelectron–photoion-coincidence technique, while the H++Cl+ formation, which follows the double ionization of HCl, has been studied by photoelectron–photoion–photoion coincidence. The photon energy threshold for the production of HCl2+ ions has been found to be 35.4±0.6 eV, while for the dissociative channel leading to H++Cl+, it has been measured a threshold at 36.4±0.6 eV and a change in the slope of the cross-section energy dependence at 38.7±0.7 eV. The production of H+Cl2+ occurs with a threshold photon energy of 42.8±1.1 eV. These results appear to be in a good agreement with previous data by different experimental techniques and recent theoretical calculations performed by our laboratory.
Product spin–orbit state resolved dynamics of the H+H2O and H+D2O abstraction reactions
Authors: Brouard M. , Burak I. , Marinakis S. , Rubio Lago L. , Tampkins P. , Vallance C.
Published: November 2004

The product state-resolved dynamics of the reactions H+H2O/D2O→OH/OD(2ΠΩ;v′,N′,f )+H2/HD have been explored at center-of-mass collision energies around 1.2, 1.4, and 2.5 eV. The experiments employ pulsed laser photolysis coupled with polarized Doppler-resolved laser induced fluorescence detection of the OH/OD radical products. The populations in the OH spin–orbit states at a collision energy of 1.2 eV have been determined for the H+H2O reaction, and for low rotational levels they are shown to deviate from the statistical limit. For the H+D2O reaction at the highest collision energy studied the OD(2Π3/2,v′=0,N′=1,A′) angular distributions show scattering over a wide range of angles with a preference towards the forward direction. The kinetic energy release distributions obtained at 2.5 eV also indicate that the HD coproducts are born with significantly more internal excitation than at 1.4 eV. The OD(2Π3/2,v′=0,N′=1,A′) angular and kinetic energy release distributions are almost identical to those of their spin–orbit excited OD(2Π1/2,v′=0,N′=1,A′) counterpart. The data are compared with previous experimental measurements at similar collision energies, and with the results of previously published quasiclassical trajectory and quantum mechanical calculations employing the most recently developed potential energy surface. Product OH/OD spin–orbit effects in the reaction are discussed with reference to simple models.
Accurate intermolecular ground state potential of the Ar-N2 van der Waals complex
Authors: Munteanu Cristian R. , Cacheiro Javier López , Fernández Berta
Published: November 2004

After carrying out a systematic basis set convergence study, we evaluate several ground state potential energy surfaces of the Ar-N2 van der Waals complex at the coupled cluster singles and doubles model including connected triples corrections. We use the aug-cc-pVXZ (X=5,Q,D) and the daug-cc-pVQZ basis sets augmented with a set of 3s3p2d1f1g (denoted 33211) and 3s3p2d2f1g (denoted 33221) midbond functions, respectively. aug-cc-pVTZ-33211 results were available in the literature. The aug-cc-pV5Z-33211 (daug-cc-pVQZ-33221) surface is characterized by a T-shaped minimum at Re=3.709 (3.701) Å and of 99.01 (102.50) cm−1, and a linear saddle point at 4.260 (4.257) Å and De=75.28 (79.73) cm−1. These results are compared with the values provided by the semiempirical potentials available, and those of previous theoretical studies. The basis set convergence of the intermolecular potentials is also analyzed. From the potentials the rovibronic spectroscopic properties are determined. We study the basis set convergence of the rotational frequencies. The binding parameters that characterized the aug-cc-pVTZ-33211 surface are reasonable, but the surface is not good enough to evaluate the microwave spectra. The aug-cc-pVQZ-33211 basis set results considerably improve the triple ζ and are close to the aug-cc-pV5Z-33211. Considering the small differences between the quadruple and the quintuple ζ surfaces, the latter results can be expected to be close to convergence. At this level the differences with respect to the accurate experimental frequencies are in the order of 0.7%. In the case of the daug-cc-pVXZ-33211,33221 (X=5,Q,T,D) series, the convergence of the interaction energies with respect to basis set improvement is not so smooth. The errors in the frequencies obtained with the daug-cc-pVQZ-33221 basis set with respect to experiment are in the order of 0.4%.
Regularization of the collision in the electromagnetic two-body problem
Authors: Hollander Efrain Buksman , De Luca Jayme
Published: November 2004

We derive a differential equation that is regular at the collision of two equal-mass bodies with attractive interaction in the relativistic action-at-a-distance electrodynamics. We use the energy constant related to the Poincaré invariance of the theory to define finite variables with finite derivatives at the collision. The collision orbits are calculated numerically using the regular equation adapted in a self-consistent minimization method (a stable numerical method that chooses only nonrunaway solutions). This dynamical system appeared 100 years ago as an example of covariant time-symmetric two-body dynamics and acquired the status of electrodynamics in the 1940s by the works of Dirac, Wheeler, and Feynman. We outline the method with an emphasis on the physics of this complex conservative dynamical system.
Reactions of silicon atoms and small clusters with CO: Experimental and theoretical characterization of SinCO (n=1–5), Si2(CO)2, c-Si2(μ-O)(μ-CSi), and c-Si2(μ-O)(μ-CCO) in solid argon
Authors: Zhou Mingfei , Jiang Ling , Xu Qiang
Published: November 2004

Reactions of silicon atoms and small clusters with carbon monoxide molecules in solid argon have been studied using matrix isolation infrared absorption spectroscopy. In addition to the previously reported SiCO monocarbonyl, Si2(CO)2 and SinCO (n=2–5) carbonyl molecules were formed spontaneously on annealing and were characterized on the basis of isotopic substitution and theoretical calculations. It was found that Si2CO, Si3CO, and Si5CO are bridge-bonded carbonyl compounds, whereas Si4CO is a terminal-bonded carbonyl molecule. The Si2(CO)2 and Si3CO molecules photochemically rearranged to the more stable c-Si2(μ-O)(μ-CCO) and c-Si2(μ-O) (μ-CSi) isomers where Si2 is inserted into the CO triple bond.
Self-diffusion in solutions of a 20 base pair oligonucleotide: Effects of concentration and ionic strength
Authors: Wilk A. , Gapinski J. , Patkowski A. , Pecora R.
Published: November 2004

The long-time self-diffusion coefficients of a 20 base pair duplex oligonucleotide are measured as functions of 20-mer and added NaCl salt concentrations. The self-diffusion coefficients decrease monotonically with increasing 20-mer concentrations for the high-added salt sample and display non-monotonically decreasing 20-mer concentration dependences at lower added salt concentrations. The non-monotonic behavior is attributed to the opposing effects of the tendency to increase the interactions between 20-mers as the concentration is increased and to a decrease in the extent of the Coulomb forces as counterions from the 20-mer increasingly screen them. Attempts to account for the effect of the Coulomb forces on the self-diffusion coefficients by using effective dimensions in the hard rod theory give good agreement with experiment at the highest salt concentration studied. For the lower salt concentrations there appear to be two scaling regimes-one at low polyion concentration in which the high salt scaling of the rod dimensions by adding the Debye screening to the length and diameter of the rod is appropriate and one at high polyion concentrations where the scaling of the dimensions is the addition of 1/2 the Debye screening length. Estimates of the “overlap” concentration C*=1/Leff indicate that the non-monotonic decrease occurs at concentrations lower than C*. Finally, the fluorescence correlation spectroscopy self-diffusion coefficients measured here are compared with the mutual diffusion coefficients measured by dynamic light scattering.
Triplet build in and decay of isolated polyspirobifluorene chains in dilute solution
Authors: King Simon , Rothe Carsten , Monkman Andy
Published: November 2004

The triplet kinetics of a conjugated polymer, polyspirobifluorene, have been studied using time resolved photoinduced absorption spectroscopy and gated emission delayed fluorescence. Working on isolated polymer chains in dilute solution, we pay particular attention to the buildup and decay of the triplet states following intersystem crossing from the excited singlet state. Confirmation of intersystem crossing as a monomolecular cold process has been made. At high excitation powers an initial fast decay of the triplet has been observed; this is attributed to intrachain triplet-triplet annihilation. From this observation we estimate the lower bound of the intersystem crossing yield as 1.2%. We also calculate the intrachain annihilation constant to be (2.9±0.1)×108 cm3 s−1.