bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photochemical reaction mechanism of cyclobutanone: CASSCF study
Authors: Chen Yishan , Ye Song 
Published: January 2004

AbstractThe photochemical reaction channels of cyclobutanone have been studied at the CASSCF level with a 6‐31G* basis set. Starting from the n‐π* excited‐state (S1) cyclobutanone, the three reactions can take place: decarbonylation (produce CO and cyclopropane or propylene), cycloelimination (produce ketene and ethylene), and ring expansion (produce oxacarbene). Our computation indicates that decarbonylation products CO and triplet trimethylene are formed on the triplet n‐π* excited state (T1) in a stepwise way via a biradical intermediate after intersystem crossing (ISC) to T1 from S1. And, then, the triplet trimethylene undergoes a second ISC to the ground state (S0) to produce the singlet trimethylene from which cyclopropane can be produced rapidly only overcoming a 1 to 2‐kcal/mol barrier while propylene can be formed as a secondary product. The cycloelimination products ketene and ethylene are formed on the S0 in a concerted mechanism after internal conversion (IC) to S0 from S1 via a biradical conical intersection. The reaction channels corresponding to ring expansion on the S0, T1, and S1 states have also been discussed, and the likeliest reaction path is that oxacarbene is formed on the ground state following S1/S0 internal conversion. The surface topology of cyclobutanone on the S1 surface is characterized by a transition state separating the minimum from the S1/S0 conical intersection, which is consistent with the previous computations and can explain the wavelength dependence of the fluorescence emission yield. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Formation of interstellar vinyl alcohol via simple radical processes: Theoretical study
Authors: Basiuk Vladimir A. , Kobayashi Kensei 
Published: January 2004

AbstractDensity functional theory calculations at the B3LYP/6‐31++G(d,p) level of theory were employed to verify whether the formation of vinyl alcohol (VA) in the interstellar medium can be explained by reactions of common and abundant interstellar species such as acetylene, radicals C2, HC C · , · OH, and H · . Several reaction sequences are possible. They include radical combinations, which proceed without activation barriers and are highly exothermic. The reactions of closed‐shell species acetylene and HCC‐OH with hydrogen atoms, as well as H‐transfer and OH‐rotation processes, might require activation energy. Nevertheless, either the corresponding transition states lay below the reactant level or there are alternative routes that involve no transition states at all, such as the reaction sequences C2 → HCC · → HCCH → trans‐syn‐HC( · )CH‐OH → syn‐VA; C2 → HCC · → syn‐≔CCH‐OH → (trans or cis)‐syn‐HC( · )CH‐OH → syn‐VA; and C2 → · CC‐OH → syn‐:CCH‐OH → (trans or cis)‐syn‐HC( · )CH‐OH → syn‐VA. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Semiempirical calculations of binding enthalpy for protein–ligand complexes
Authors: Nikitina E. , Sulimov V. , Zayets V. , Zaitseva N. 
Published: January 2004

AbstractA systematic semiempirical quantum mechanical study of the interactions between proteins and ligands has been performed to determine the ability of this approach for the accurate estimation of the enthalpic contribution to the binding free energy of the protein–ligand systems. This approach has been applied for eight test protein–ligand complexes with experimentally known binding enthalpies. The calculations were performed using the semiempirical PM3 approach incorporated in the MOPAC 97, ZAVA originally elaborated in Algodign, and MOPAC 2002 with MOZYME facility packages. Special attention was paid to take into account structural water molecules, which were located in the protein–ligand binding site. It was shown that the results of binding enthalpy calculations fit experimental data within ∼2 kcal/mol in the presented approach. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
“Plasma Polymers and Related Materials – COST Aktion 527”
Authors: Oehr Christian , Fellenberg Ralf 
Published: February 2004

AbstractZur Stärkung der Zusammenarbeit zwischen Europäischen Forschungseinrichtungen und zur Gestaltung eines Europäischen Forschungsraums gibt es zahlreiche Aktivitäten. Eine davon sind sogenannte COST‐Aktionen. In diesem Beitrag wird die COST‐Aktion 527, die von der EU durchgeführt wird, vorgestellt. Zentrales Thema dieser Aktion ist die Verwendung von Plasmatechniken zur Abscheidung dünner polymerer Schichten auf verschiedenen Materialien.
Kompakte trockenlaufende Vakuumpumpen. Compact Dry Vacuum Pumps
Authors: Dirschel Jürgen , Lachenmann Rudolf 
Published: February 2004

AbstractMembranvakuumpumpen finden immer weitere Verbreitung beispielsweise als Vorpumpen für Weitbereichs‐Turbopumpen, Gasanalysatoren und andere Laboranwendungen. Große Fortschritte bei der Membrantechnologie durch den Einsatz numerisch optimierter Flachmembrane sowie durch elektronisch gesteuerte Antriebssysteme machen Membranvakuumpumpen noch kompakter, leistungsfähiger und zuverlässiger. Wartungsintervalle von über 40.000 Betriebsstunden – ähnlich denen von Turbopumpen – erscheinen bei drehzahlgeregelten Systemen mittlerweile realisierbar.
Adolescents’ outcome expectancies about relational aggression within acquaintanceships, friendships, and dating relationships
Authors: Goldstein Sara E. , Tisak Marie S. 
Published: January 2004

AbstractAdolescents’ (N=292) relational aggression and outcome expectancies for relational aggression in three different relationship contexts (acquaintanceship, friendship, and dating) were assessed. With respect to each type of relationship, adolescents were questioned about the emotional and dyadic consequences of relational aggression, and about whether the victim of relational aggression would retaliate. It was also of interest to assess whether adolescents’ personal involvement in relational aggression was associated with these judgments. The results suggest that adolescents’ involvement in relational aggression and outcome expectancies for relational aggression often varies by gender, age, relationship context, and type of relational aggression. Additionally, in several instances, adolescents’ personal involvement in relational aggression was associated with outcome expectancies for relational aggression. For example, after gender and age had been accounted for, participants’ own relational aggression predicted beliefs about whether the victim of relational aggression would want to continue a friendship and a dating relationship. Implications of the results and future directions for research are discussed.
Periodicity of atmospheric phenomena occurring in the extreme South of Brazil
Authors: Campello Fernando D. , Saraiva Jaci M.B. , Krusche Nisia 
Published: February 2004

AbstractSpectral analysis revealed oscillations associated to atmospheric phenomena in the extreme south of Brazil. Cycles from 36 to 77 days, linked to Madden–Julian Oscillation, from 18 to 28 days, related to the bipolar South Atlantic Convergence Zone‐Subtropics mode and 10‐day oscillations due to the passage of frontal systems were detected. Copyright © 2004 Royal Meteorological Society. Published by Elsevier Ltd. All rights reserved.
Expression of the CD44 variant isoform 5 in the human osteoarthritic knee joint: Correlation with radiological, histomorphological, and biochemical parameters
Authors: Fuchs Susanne , Dankbar Berno , Wildenau Gunnar , Goetz Werner , Lohmann Christoph H. , Tibesku Carsten O. 
Published: January 2004

AbstractPurpose: The purpose of this study was to correlate expression of CD44v5 in osteoarthritic synovium, cartilage, and synovial fluid with radiographical, histomorphological, and biochemical data.Methods: Cartilage and synovia specimens of 27 patients with osteoarthritis were histomorphologically assessed according to Mankin and Pelletier, respectively. Extended weight‐bearing antero‐posterior radiographs were evaluated according to Kellgren and Ahlback. Expression of membrane‐bound CD44v5 was analyzed by immunohistochemistry and levels of soluble CD44v5 were determined by ELISA.Results: Expression of CD44v5 in cartilage and synovia was detected in 67% and 59% of the patients, respectively. Immunohistochemical findings in cartilage correlated significantly with structural cartilage changes (p < 0.001), whereas no correlation was found between expression in synovia and inflammatory synovial changes. Additionally, no relationship was evident between CD44v5 expression and radiographical data, but expression in cartilage and synovium was significantly correlated with each other (p < 0.04). Surprisingly, expression of CD44v5 in both cartilage and synovia was negatively correlated with synovial fluid levels of TNFα (p < 0.03 and p < 0.02, respectively), and no association was evident with levels of IL‐1β.Conclusions: The data demonstrate expression of CD44v5 in osteoarthritic cartilage and synovia, probably independent of joint inflammation. But more importantly, expression of this receptor variant in cartilage seems to be strongly related to the degree of cartilage destruction. © 2003 Published by Elsevier Ltd. on behalf of Orthopaedic Research Society. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
The influence of cyclic compression and distraction on the healing of experimental tibial fractures
Authors: Hente R. , Füchtmeier B. , Schlegel U. , Ernstberger A. , Perren S. M. 
Published: January 2004

AbstractInterfragmentary displacement has a main effect on callus formation in fracture healing. To test whether compressive or distractive displacements have a more pronounced effect on new bone formation, a sheep osteotomy model was created whereby the gap tissue was subjected to constant bending displacement. A diaphyseal osteotomy with a gap of 2 mm was created in 18 sheep tibiae and stabilized with a special unilateral actuator‐driven external fixator. Two experimental groups with six sheep each received either 10 or 1000 cycles evenly distributed over 24 h. The third group of six sheep served as a control group without actively induced displacement. The amount and direction of cyclic displacement was kept constant throughout the observation period, resulting in 50% compressive and 50% distractive displacement within the osteotomy gap. At sacrifice, six weeks after surgery, bending stiffness was measured and new bone formation was assessed radiologically and microradiographically. In all cycled groups, the amount of periosteal callus formation was up to 25 times greater on the compression compared to the distraction side (p < 0.001). The application of the higher number of daily cycles resulted in an up to 10‐fold greater amount of periosteal new bone formation on the compression side (p < 0.012), while the difference on the distraction side was not significant. Ten cycles applied a day were sufficient to create an abundant periosteal callus on the compression side. In the 1000 cycle group, bending stiffness revealed slightly lower values but the difference was not significant. Solid periosteal bridging of the gap was observed in two sheep in the control group, whereas bridging in the cycled groups was observed exclusively at the medullary side. In conclusion, cyclic compressive displacements were found to be superior over distractive displacements. A higher number of enforced and maintained compressive displacements enhanced periosteal callus formation but did not allow bony bridging of the gap. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Electoral Justice in Mexico: The Role of the Electoral Tribunal under New Federalism
Authors: BERRUECOS SUSANA 
Published: January 2004

‘Demanding adherence to principles is, either, to accept the federal system with all its advantages and dangers, or to denounce it frankly and proclaim the empire of central government, granting it the power to correct the abuses that local authorities might commit.’Ignacio VallartaThe annulment of the 2000 gubernatorial elections in Tabasco marked a fundamental precedent for electoral justice in Mexico and the role of the Electoral Tribunal of the Federal Judiciary (Tribunal Electoral del Poder Judicial de la Federación – TEPJF) in federal, state and local elections. Successive constitutional reforms that ended with the ‘definitive’ electoral reforms of 1996 have consolidated a regime of electoral dispute adjudication at the federal level, giving political parties the right to appeal state cases before federal authorities. Whereas a clear tendency exists towards greater decentralisation of power under ‘new federalism’, in the electoral field centralism concentrated on the TEPJF and the Supreme Court of Justice has been adopted. However, in the context of political pluralism and a more authentic federalism, the TEPJF's new role has caused conflicting reactions. Some sectors are insisting on the need to limit this institution's powers so that in the future it can only rule over subnational elections based on well-defined criteria that respect specific jurisdictional principles.
Democratisation, War and State-Building: Constructing the Rule of Law in El Salvador
Authors: CALL CHARLES T. 
Published: January 2004

After long neglecting issues of citizen security and justice, democratisation theorists have recently begun to recognise the importance of the rule of law. Yet theorising the construction of state institutions of security and justice has tended to be piecemeal and divorced from broader theoretical debates. Using the case of post-war El Salvador, this article first argues that justice and security are tremendously important for the survivability and everyday relevance of democracy, given that crime is the chief threat to support for democracy.Second, the article explores competing views of institutional reform. It finds support for path-dependent ‘mode-of-transition’ approaches that postulate heightened agency to adopt new rules and reform institutions during uncertain transition periods. However, more sceptical cultural and institutional theorists are right insofar as the formal removal of authoritarian structures and personnel is easier than the informal transformation of state practices and of society's attitudes about state services. The article also finds that security (i.e., military, intelligence and police) reforms operate differently to judicial reforms, which were more difficult and were less tied to the country's peace process. The interaction of these reform processes with a post-war crime wave helps explain why international observers consider El Salvador's reforms a success story, but many Salvadoreans do not.
Gender differences in response to differing antidepressant drug classes: two negative studies
Authors: PARKER G. , PARKER K. , AUSTIN M.-P. , MITCHELL P. , BROTCHIE H. 
Published: January 2004

Background. A recent US study presented data suggesting that depressed women are more likely to respond to selective serotonin reuptake inhibitor (SSRI) than tricyclic (TCA) antidepressant drug therapies. We have undertaken replication studies in two independent databases.Method. We have examined for gender differences in SSRI and TCA antidepressant response in both retrospective and prospective naturalistic uncontrolled studies, and in subsets of melancholic and non-melancholic depressed subjects. As the US study had indicated that women under the age of 40 years were particularly likely to show a differential response to SSRIs, we examined for age, gender and interactional effects. In addition, we examined for differential SSRI and TCA responsiveness in a subset of patients who had received drugs from both classes.Results. We failed to find evidence of women having a preferential response to SSRI medication or, conversely, of men having a superior response to TCA medication. Older age, however, was associated with a superior TCA response and younger age with a superior SSRI response.Conclusion. As few studies have examined for differential gender and age effects in response to narrow action and broad action antidepressant drugs across major depressive subtypes, gender differential effects remain to be established.
Kinematical analysis of emotionally induced facial expressions in patients with obsessive–compulsive disorder
Authors: MERGL R. , VOGEL M. , MAVROGIORGOU P. , GÖBEL C. , ZAUDIG M. , HEGERL U. , JUCKEL G. 
Published: January 2004

Background. Motor function is deficient in many patients with obsessive–compulsive disorder (OCD), especially in the face. To investigate subtle motor dysfunction, kinematical analysis of emotional facial expressions can be used. Our aim was to investigate facial movements in response to humorous film stimuli in OCD patients.Method. Kinematical analysis of facial movements was performed. Ultrasound markers at defined points of the face provided exact measurement of facial movements, while subjects watched a humorous movie (‘Mr Bean’). Thirty-four OCD patients (19 male, 15 female; mean (S.D.) age: 35·8 (11·5) years; mean (S.D.) total Y-BOCS score: 25·5 (5·9)) were studied in unmedicated state and after a 10-week treatment with the SSRI sertraline. Thirty-four healthy controls (19 male, 15 female; mean (S.D.) age: 37·5 (13·1) years) were also investigated.Results. At baseline, OCD patients showed significantly slower velocity at the beginning of laughing than healthy controls and a reduced laughing frequency. There was a significant negative correlation between laughing frequency and severity of OCD symptoms. Ten weeks later a significant increase of laughing frequency and initial velocity during laughing was found.Conclusions. Execution of adequate facial reactions to humour is abnormally slow in OCD patients. Susceptibility of OCD patients with regard to emotional stimuli is less pronounced than in healthy subjects. This phenomenon is closely correlated to OCD symptoms and is state-dependent.
Ghrelin and leptin responses to food ingestion in bulimia nervosa: implications for binge-eating and compensatory behaviours
Authors: MONTELEONE P. , MARTIADIS V. , FABRAZZO M. , SERRITELLA C. , MAJ M. 
Published: January 2004

Background. Ghrelin and leptin are endogenous peripheral proteins involved in the regulation of eating behaviour. In particular, ghrelin stimulates hunger and promotes food ingestion, whereas leptin increases satiety and reduces food consumption. Therefore, alterations in the physiology of these peptides may play a role in the pathogenesis of eating disorders such as bulimia nervosa. In the present study, we investigated ghrelin and leptin responses to food ingestion in patients with bulimia nervosa.Method. Nine symptomatic drug-free bulimic women and 12 age-matched healthy women ingested a meal of 1207 kcal (60% carbohydrates, 23% fat and 17% proteins) at 12.00 a.m. and underwent blood sample collection before and 45, 60, 90, 120 and 180 min after the meal. Plasma levels of ghrelin, leptin, insulin and glucose were measured.Results. In healthy women, circulating ghrelin exhibited a drastic decrease after the food intake whereas, in bulimic patients, this response was significantly blunted. No difference between the two subjects groups was observed in post-prandial profiles of plasma leptin, insulin and glucose.Conclusions. The lack of a leptin response to food ingestion, in both bulimic and healthy women, is compatible with the role of this peptide as long-term rather than short-term modulator of eating behaviour. The blunted ghrelin response to food ingestion may support the occurrence in bulimic subjects of an impaired suppression of the drive to eat following a meal. This may have implications for binge-eating.
Socio-economic status, family disruption and residential stability in childhood: relation to onset, recurrence and remission of major depression
Authors: GILMAN S. E. , KAWACHI I. , FITZMAURICE G. M. , BUKA S. L. 
Published: January 2004

Background. Childhood adversity significantly increases the risk of depression, but it is unclear whether this risk is most pronounced for depression occurring early in life. In the present study, we examine whether three aspects of childhood adversity – low socio-economic status (SES), family disruption, and residential instability – are related to increased risk of depression during specific stages of the life course. We also examine whether these aspects of childhood adversity are related to the severity of depression.Method. A sample of 1089 of the 4140 births enrolled in the Providence, Rhode Island cohort of the National Collaborative Perinatal Project was interviewed between the ages of 18 and 39. Measures of parental SES, childhood family disruption and residential instability were obtained upon mother's enrolment and at age 7. Age at onset of major depressive episode, lifetime number of depressive episodes, and age at last episode were ascertained via structured diagnostic interviews. Survival analysis was used to identify risk factors for depression onset and remission and Poisson regression was used to model the recurrence rate of depressive episodes.Results. Low parental SES, family disruption and a high level of residential instability, defined as three or more family moves, were related to elevated lifetime risks of depression; the effects of family disruption and residential instability were most pronounced on depression onset by age 14. Childhood adversity was also related to increased risk of recurrence and reduced likelihood of remission.Conclusions. Childhood social disadvantage significantly influences risk of depression onset both in childhood and in adulthood. Early childhood adversity is also related to poor prognosis.
Risk and Resiliency Factors Influencing Suicidality Among Urban African American and Latino Youth
Authors: O'Donnell Lydia , O'Donnell Carl , Wardlaw Dana Meritt , Stueve Ann 
Published: February 2004

AbstractFor decades, suicide rates among minority African American and Latino young people have been stable and, when compared with Whites, relatively low. This is no longer the case, underscoring the need for documenting and understanding the problem of suicidality in this population. We report on the prevalence and predictors of suicidality among 879 urban adolescents in the Reach for Health study. All youth resided in economically disadvantaged neighborhoods; 69% were African American, 16% Latino, and 15% reported mixed or other ethnicity. In the past year, 15% had seriously considered suicide; 13% had made a suicide plan, 11% had attempted suicide at least once, and 4% reported multiple attempts. Risk factors significantly related to suicidal ideation are being female, having basic needs unmet, engaging in same‐gender sex, and depression. Resiliency factors include family closeness and, marginally, religiosity. Risk factors related to reports of suicide attempts are being female, being Hispanic, and depression; family closeness is strong resiliency factor. Family composition, ethnic identity, coping style, peer support, and school attachment are not significant correlates of suicidal ideation or attempts.