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PubMed2006

Structures of coincidence symmetry groups.

The structure of the coincidence symmetry group of an arbitrary n-dimensional lattice in the n-dimensional Euclidean space is considered by describing a set of generators. Particular attention is given to the coincidence isometry subgroup (the subgroup formed by those coincidence symmetries that are elements of the orthogonal group). Conditions under which the coincidence isometry group can be generated by reflections defined by vectors of the lattice are discussed and an algorithm to decompose an arbitrary element of the coincidence isometry group in terms of reflections defined by vectors of the lattice is given.

Journal Article↗
PubMed2006

Differences in the domain forming properties of N-palmitoylated neutral glycosphingolipids in bilayer membranes.

We have compared the domain forming properties of three neutral acyl chain defined glycosphingolipids differing in their head group structures. The aim of the study was to explore if glycosphingolipids and sterols exist in the same lateral domains in bilayer membranes and how the structure of the head group influences the capacity of the glycosphingolipids to colocalize with cholesterol. The glycosphingolipids used in the study were galactosyl-, glucosyl- and lactosylceramides with a palmitic acid in the N-linked position. Domain formation in mixed bilayer vesicles was examined using fluorescent reporter molecules associating with ordered domains, together with a fluorescence quencher lipid in the disordered membrane phase. Our results show that the glycosphingolipids studied were poor in forming sterol-enriched domains compared to palmitoyl-sphingomyelin as detected by cholestatrienol quenching. However, the tendency to associate with cholesterol was clearly dependent on the carbohydrate structure of the glycosphingolipids, also when two glycosphingolipids with different head groups were mixed in the bilayer. All palmitoylated glycosphingolipids associated with palmitoyl-sphingomyelin/cholesterol domains. Our results show that the head group structures of neutral glycosphingolipids markedly affect their domain forming properties in bilayers both with and without cholesterol. The most striking observation being that large differences in domain forming properties were seen even between glucosylceramide and galactosylceramide, which differ only in the stereochemistry of one hydroxyl group in the carbohydrate head group.

Cell Membrane↗
PubMed2004

Taking charge of epilepsy: the development of a structured psychoeducational group intervention for adolescents with epilepsy and their parents.

Children and adolescents with epilepsy frequently experience poor psychosocial outcomes due to numerous factors such as perceived stigma, behavior problems, academic difficulties, and depression. Health psychology research has documented the effectiveness of psychoeducational interventions aimed at improving psychosocial outcomes for individuals with a variety of health conditions. With increasing numbers of adolescents living with epilepsy, interest in improving the quality of life for this particular population has grown. There remains, however, a paucity of research concerning psychosocial interventions for adolescents with epilepsy. The present study outlines the development and initial implementation of a 6-week structured psychoeducational group intervention for adolescents with epilepsy and their parents. Preintervention, the QOLIE-AD-48, Childhood Depression Inventory, and Revised Children's Manifest Anxiety Scale were administered. Educational topics included medical aspects of epilepsy, healthy lifestyle behaviors, family and peer relationships, understanding self-image and self-esteem, and stress management techniques. Participants were introduced to a variety of cognitive-behavioral strategies, and were encouraged to share their own experiences with epilepsy. Feedback from adolescent and parent participants indicated that the intervention was relevant to their needs, helped them better understand their epilepsy, and allowed an opportunity for positive peer support. Also, postintervention outcome measurement indicated an overall positive trend for quality of life improvement in the adolescents.

Adaptation, Psychological↗
PubMed2005

[Stress analysis of the post and core system under loading].

PURPOSE: To analyze the stress of the post and core system by using finite element analysis and study the influence of the "crown materials" on the analytic results. METHODS: Three groups of 3D finite element models of maxillary incisors were established according to the fabricating standard of the post and core system by using I-DEAS finite element analysis software. Group A was consisted of the cast metal post and core, the tooth structure after preparation and the periodontal structure. Group B was composed of the PFM, the cast metal post and core, the tooth structure after preparation and the periodontal structure. Group C was composed of the resin crown, the cast metal post and core, the tooth structure after preparation and the periodontal structure. The three groups were loaded and analyzed under the same loading according to the mean value of the bite force of incisors. RESULTS: (1)The maximum stress of dentin in group A was twice higher than that in group B. The maximum primary stress, minimum primary stress and maximum shear stress of group A were respectively 236.35, 228.83 and 218.05 percent of those in group B. The difference of maximum stress values of group B and group C was neglectable. (2) The maximum stress distribution of dentin in group A and group B was quite different (the stress was concentrated in labial and lingual side of the cervical dentin in group A, otherwise in group B it was concentrated in the area around the alveolar and the labial and lingual side of the dentin which was opposite to the tip of the cast metal post and core). The maximum stress distribution of dentin in group A and group B was almost the same. CONCLUSIONS: Different materials of the crown did not influence the result of 3D finite element stress analysis of the post and core system.

Bite Force↗
PubMed2002

Collective memory and spatial sorting in animal groups.

We present a self-organizing model of group formation in three-dimensional space, and use it to investigate the spatial dynamics of animal groups such as fish schools and bird flocks. We reveal the existence of major group-level behavioural transitions related to minor changes in individual-level interactions. Further, we present the first evidence for collective memory in such animal groups (where the previous history of group structure influences the collective behaviour exhibited as individual interactions change) during the transition of a group from one type of collective behaviour to another. The model is then used to show how differences among individuals influence group structure, and how individuals employing simple, local rules of thumb, can accurately change their spatial position within a group (e.g. to move to the centre, the front, or the periphery) in the absence of information on their current position within the group as a whole. These results are considered in the context of the evolution and ecological importance of animal groups.

Animals↗
PubMed1997

Girls, pecking order and smoking.

Against a background of growing concern about the failure to reduce cigarette smoking amongst young people, particularly girls, this paper attempts to unravel the complex interrelationships between smoking, peer group structure and gender. We were particularly intrigued to explore a recent hypothesis in the literature that suggests that girls who smoke, far from lacking self-esteem, are more self-confident and socially skilled than their non-smoking peers. Sociometric and qualitative analyses revealed that smoking behaviour was indeed shaped by gender, and that the psychosocial processes involved in smoking uptake may be different for boys and than for girls. Peer group structure, consistently described by young people as hierarchical, was closely related to smoking behaviour. Girls at the top of the social pecking order who projected an image of high self-esteem were identified as most likely to smoke, while only a small minority of girls fitted the stereotype of the young female smoker who has poor social skills and low self-esteem. Boys of high social status were less vulnerable, since sport and a desire to be fit to some extent protected them. Our findings raise fundamental questions about the meaning of self-esteem in relation to smoking uptake, arguing instead for an exploration of the term "self-worth". They suggest the need for health education programmes which are sensitive both to gender and to peer group structures.

Adolescent↗
PubMed1979

Psychosomatic illness as a result of a deficit in ego-structure under consideration of the genetic. Dynamic, structural, and group dynamic point of view.

Psychosomatic illness is an illness of ego-structure as a result of a narcissistic deficit reassembling the phenomenology of anaclitic depression in regard to the mother and the primary group. Psychosomatic illness has to be understood on a scale of ego-illnesses related to identity defects. The psychosomatic symptom restitutes the integration of the personality and constitutes the identity of a psychosomatic patient. The role of group dynamics is particularly stressed in relation to psychogenetics, psychodynamics, and the change of symptoms.

Aggression↗
PubMed2001

Solid-state structures of group 1 and group 2 metal 1,5-naphthalenedisulfonates: systematic investigation of lamellar three-dimensional networks constructed by metal arenedisulfonate.

Seven Group 1 and Group 2 1,5-naphthalenedisulfonates (1,5-nds) have been synthesized and structurally characterized by single-crystal X-ray diffraction, IR spectroscopy and thermal gravimetric analysis. For Group 1 metal complexes, with M = Li(+) (1), Na(+) (2) and K(+) (3), all crystallize in the same space group (P2(1)/c) with the same composition, [M(2)(1,5-nds)(H(2)O)(2)]. They adopt similar three-dimensional packing arrangements with the metal-sulfonate inorganic layers pillared by naphthalene rings. However, the coordination behavior of three metal cations toward the SO(3)(-) group and water molecule are different, resulting in different architectures for the inorganic portion. For Group 2 complexes with M = Mg(2+) (4), Ca(2+) (5), Sr(2+) (6) and Ba(2+) (7), Mg(2+) shows no direct coordination by the SO(3)(-) group while Ca(2+) is coordinated by four SO(3)(-) groups and a two-dimensional network is formed. Complexes (6) and (7) are isostructural, adopting the same three-dimensional, inorganic-organic pillared framework as seen for (1)-(3). The coordination behavior of the metal cations in these structures neatly illustrates the increase in coordination strength with decreasing charge/radius ratio for Group 1 and Group 2 metal cations with large organic anions.

Journal Article↗
PubMed1999

Treatment effects with an adolescent abuse survivor's group.

OBJECTIVE: The goal of the study was to demonstrate the efficacy of a structured group therapy intervention in reducing the negative emotional and behavioral sequelae of adolescent girls' who are survivors of sexual abuse. It was hypothesized teens would show an increase in adaptive behaviors and knowledge of positive coping strategies. METHOD: A 7-session structured group treatment protocol based on Solution Focused and Ericksonian interventions was used. Forty-one teens between the ages of 13 and 18 years old participated in the groups. Each group session included a didactic presentation. an art activity and development of a positive associational cue. Pre- and post-test assessment was done using the Solution Focused Recovery Scale, a measure of adaptive functioning; and the Skill Mastery Test, designed to evaluate teens knowledge of the concepts and strategies taught throughout the group. RESULTS: Overall, there was a significant change in pre- to post- measurements of adaptive functioning as assessed by the Recovery Scale. At this time, no statistically significant pre- to post- changes were evident for scores on the Skill Mastery Test. However, there was a trend toward improvement on visual inspection of the Skill Mastery scores. CONCLUSIONS: This study demonstrates emphasizing competence and skill development in the treatment of adolescent abuse survivors can aid teens in improving their daily functioning and positive recovery behaviors. In addition, early findings regarding the efficacy of this intervention suggest theory driven research methodology can be applied in a clinical setting with standardized treatment protocols.

Adolescent↗
PubMed1992

Personality traits of a group of young adults from different family structures.

The impact of parental divorce and remarriage and young adults' gender on second-order personality traits, such as extraversion, anxiety, tough poise and independence, was examined. The responses of 227 young adults on the Sixteen Personality Factor Questionnaire (16PF; Cattell, Eber, & Tatsuoka, 1970) were subjected to a parametric multivariate analysis of variance. Results revealed significant differences between the anxiety scores of the young men and women as well as between those of the three different family-structure groups, but divorce and remarriage was not associated with either positive or negative personality development in this sample.

Adolescent↗
PubMed1976

The Post-Mastectomy Rehabilitation Group program. Structure, procedure, and population demography.

Memorial Hospital, New York City, clinical section of the Memorial Sloan-Kettering Cancer Center, has developed a Post-Mastectomy Rehabilitation Group (PMRG) which provides a comprehensive structure program to enable the mastectomy patient to regain functional use of her arm and shoulder on the affected side, and to adapt functionally, psychologically, and emotionally to the loss of her breast and the diagnosis of cancer in the shortest time possible. This first segment of an evaluation of the program outlines the PMRG structure and operating procedures and presents basic demographic data (age, type of mastectomy, preoperative activity status) for 863 of the 1,400 mastectomy patients who attended the program since inception in 1970. Additional reports will focus on the physical and psychologic aspects of recovery and readjustment.

Adult↗
PubMed2005

Novel chain structures in group VI elements.

Recent developments in high-pressure methods and advances in X-ray crystallography have led to a new level of understanding of phase diagrams and structures of materials under pressure. Recently discovered phenomena such as complex phases of alkali metals, incommensurate host-guest structures, and incommensurately modulated structures have rendered obsolete our conventional wisdom about the range of structures possible in the elements. Using new in situ diffraction techniques, we have resolved the long-standing problem of the phase-transition sequence of sulphur in its non-metallic state. We demonstrate that it is very different from that previously proposed, with only two phases stable between 1.5 GPa and 83 GPa (the pressure of metallization), and temperatures from 300 K to 1,100 K. The phases have a triangular chain and a squared chain structure. The same squared chain structure is found in the heavier group VI element selenium.

Journal Article↗