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PubMed1987

The role of group structure in the action of some morpholinium chloride derivatives on model systems.

Effects of morpholinium chlorides, which exhibit fungicidal activity, on model lipid systems is discussed. It was shown by means of DSC and BLM techniques that for different salts possessing alkyl chains of identical length, the interaction with lipids depends strongly on the polar head charge and the structure of the salt. The results obtained and conclusions drawn can be useful in explaining the possible mechanism of the biological effectiveness of the compounds tested; this is suggested by the observation that salts tested showed the same sequence of activity in both biological tests and model experiments.

Antifungal Agents↗
PubMed2004

Adult and group influences on participation in youth empowerment programs.

This study examined adult and group influences on youth participation in youth empowerment (YE) Statewide Youth Movement Against Tobacco Use programs. Adults provide individual guidance to youth groups and through existing tobacco control networks affect the social context in which YE programs are implemented. The authors tested hypotheses about the direct and indirect relationships between adults, groups, and youth collective participation. They used data from adults and youths to develop a measurement model of four higher order factors: adult involvement, group structure, group climate, and collective participation. They tested relationships between these factors in a structural equation model. Results showed that adult involvement did not have a meaningful direct effect on group factors or collective participation. Group factors mediated the relationship between adult involvement and collective participation. Further research is needed on how to measure adult involvement and its relationship to youth participation.

Adolescent↗
PubMed2005

Mixed messengers, unified message: spatial grouping from temporal structure.

In dynamic visual environments, objects can differ from their backgrounds in terms of their associated temporal structure--the time course of changes in some stimulus property defining object and background. In a series of experiments, we investigated whether different "messengers" of temporal structure group into coherent spatial forms. Observers viewed arrays of Gabor patches in which different temporal structures designated figure and ground regions; extracting the figure required grouping across synchronized orientation, spatial frequency, phase, and/or contrast changes. Observers were able to extract spatial form from temporal structure even when information had to be combined across different messengers. Further, mixing messengers of temporal structure proved cost-free: task performance when grouping across messengers approximated performance when all information resided within a single messenger. Thus, the visual system can abstract temporal structure regardless of the messenger of the dynamic event; a coherent spatial structure emerges from this abstracted temporal structure.

Artifacts↗
PubMedDate not supplied

The pregnant adolescent--a group approach.

This paper has described the groups for pregnant teenagers developed in the Rochester Adolescent Maternity Project. One and one-half year's experience with these groups has allowed the authors time to begin their study of groups and to write a descriptive paper of their evolution. The groups' development goes on while the leaders continue their own theoretical study of groups at this writing. Groups for pregnant adolescents have ranged from group therapy sessions to structured groups where only didactic material is presented. The literature is somewhat limited in its discussion of types of groups and especially in describing group process. This paper differs from others in that both group structure and process, based on the group objectives, are discussed. Information on approaches beneficial to the adolescent have been included. The goals of the group are to help the teenagers work through the developmental tasks of adolescence and pregnancy and to prepare them for the labor, delivery, and initial parenthood experience. Group structure is based on the intent to engage teenagers in resolution of these tasks in order to be prepared at a variety of levels, i.e. cognitive, emotional, etc., for labor, delivery, and parenthood. Co-leadership of the groups and an unstructured format facilitate the movement of the group toward accomplishment of its objectives. Group content issues were explored and techniques developed to handle these issues were suggested. Included were the following: 1. Commitment to the group by the members is assisted by the structure set for the group and the leaders' active outreach to members. 2. Descriptions of emotions and thoughts are made in concrete rather than abstract terms because of the developmental status of the teenagers. 3. Expression of personal feelings, often difficult for teenagers, is aided by the use of a projective technique. 4. Transition from leader-oriented to group-directed discussion is made possible by the group leaders gradually changing their leadership from one of direct interaction to one of facilitating discussion. 5. Polarization of the group in a negative or positive direction is prevented through the use of a neutral group member or active intervention by the group leaders taking on a neltral role. 6. Control, an issue of pregnancy and adolescence, is dealt with on interactional, educational, and emotional levels. 7. Termination is determined by the stage of the group "work" and is identified and facilitated by the group leaders. Research questions needed to document the effectiveness of the group approach to the pregnant adolescent were addressed.

Adolescent↗
PubMed2003

Structural modulation of Cu(I) and Cu(II) complexes of sterically hindered tripyridine ligands by the bridgehead alkyl groups.

Structures of Cu(I) and Cu(II) complexes of sterically hindered tripyridine ligands RL = tris(6-methyl-2-pyridyl)methane (HL), 1,1,1-tris(6-methyl-2-pyridyl)ethane (MeL), and 1,1,1-tris(6-methyl-2-pyridyl)propane (EtL), [Cu(RL)(MeCN)]PF(6) (1-3), [Cu(RL)(SO(4))] (4-6), and [Cu(RL)(NO(3))(2)] (7-9), have been explored in the solid state and in solution to gain some insights into modulation of the copper coordination structures by bridgehead alkyl groups (CH, CMe, and CEt). The crystal structures of 1-9 show that RL binds a copper ion in a tridentate facial-capping mode, except for 3, where EtL chelates in a bidentate mode with two pyridyl nitrogen atoms. To avoid the steric repulsion between the bridgehead alkyl group and the 3-H(py) atoms, the pyridine rings in Cu(I) and Cu(II) complexes of MeL and EtL shift toward the Cu side as compared to those in Cu(I) and Cu(II) complexes of HL, leading to the significant differences in the nonbonding interatomic distances, H.H (between the 3-H(py) atoms), N.N (between the N(py) atoms), and C.C (between the 6-Me carbon atoms), the Cu-N(py), Cu-N(MeCN), and Cu-O bond distances, and the tilt of the pyridine rings. The copper coordination geometries in 4-6, where a SO(4) ligand chelates in a bidentate mode, are varied from a square pyramid of 4 to distorted trigonal bipyramids of 5 and 6. Such structural differences are not observed for 7-9, where two NO(3) ligands coordinate in a monodentate mode. The structures of 1-9 in solution are investigated by means of the electronic, (1)H NMR, and ESR spectroscopy. The (1)H NMR spectra show that the structures of 1-3 in the solid state are kept in solution with rapid coordination exchange of the pyridine rings. The electronic and the ESR spectra reveal the structural changes of 5 and 6 in solution. The bridgehead alkyl groups and 6-Me groups in the sterically hindered tripyridine ligand play important roles in modulating the copper coordination structures.

Journal Article↗