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Biomedical subjects

B Segal

Publications and source records attributed to B Segal.

At least 91 records · Page 5Linked to original sources
PubMedDate not supplied

Confirmatory analyses of reasons for experiencing psychoactive drugs during adolescence.

This study established empirically defined reasons for experiences with psychoactive drugs by adolescents. By means of cross-validating procedures involving a series of principal component analyses of data obtained from three separate sample groups, three common motives or reasons for trying/taking drugs were derived: a tension-reduction, or coping motive; a drug-effect motive; and a peer-related motive. The implications of the findings for further research and for treatment and prevention programs are reviewed.

Adolescent↗
PubMedDate not supplied

ADH and ALDH polymorphisms among Alaska Natives entering treatment for alcoholism.

The alcohol dehydrogenase (ADHs) and aldehyde dehydrogenases (ALDHs) involved in alcohol metabolism are polymorphic. Different alleles encode subunits of the enzymes that are related to differences in alcohol metabolism with different ethnic groups. This study examined the allele frequencies at the ADH1, ADH2, ADH3 and ALDH2 loci in Alaska Natives entering treatment for alcoholism to determine if allele frequencies at these loci differ among five distinct Alaska Native groups: Yupik and Inupiat Eskimos, Athabascan, Tlingit and Aleut. It was found that all persons were homozygous for the ADH1*1, ADH2*1 and ALDH2*1 alleles. Variations, however, were found for the allele distribution of the ADH3 genotype. Comparison with a general population sample found no differences in allele distributions for ADHs and ALDH2*1, but differences were found when comparisons were made with four Asian Groups. The study's findings suggest that the Alaska Natives are not protected from the risk of alcoholism in the same way that Asians who possess the ALDH2*2 genotype are considered to have a negative risk factor. Nor, does there appear to be any generalized differences between Alaska Native alcoholics and members of the general population with respect to the ALDH and ADH polymorphisms studied herein.

Adolescent↗
PubMedDate not supplied

Can minimum separation criteria ensure electromagnetic compatibility in hospitals? An experimental study.

Electromagnetic interference (EMI) from radiofrequency (RF) sources can cause medical device malfunction. It has been proposed that such EMI be minimized by only operating sources of given RF powers when sufficiently separated from medical devices of given immunities. Such minimum separation criteria are estimated assuming free-space propagation, which is only valid in the ideal case. Yet proposed medical device EMC standards will require that minimum-separation criteria be listed in equipment manuals accompanying all new medical devices. It is essential that the practical utility of such minimum-separation criteria be evaluated. Fields due to an 800-MHz-type cellphone were measured in various rooms and corridors within an urban hospital, having both new (gyprock) and old (clay-block) wings. Data obtained from a calibrated antenna attached to a spectrum analyzer were repeatedly measured and averaged. Results were compared to those predicted by free-space propagation. Free-space predictions tended to overestimate measured fields in gyprock rooms and along corridors of both gyprock and clay-block construction. However, the free-space model tended to underestimate field levels predicted in clay-block rooms and in below-ground corridors. Usage of separation criteria to ensure EMC appeared useful in gyprock rooms and hospital corridors, but less so in rooms with clay-block walls or in below-ground sections of the hospital. This suggested that the latter regions should be considered as being special zones where side-by-side operation of RF sources and medical devices would require more conservative management (e.g., restriction or special approval of particular source or medical device).

Electric Conductivity↗