ABSTRACT
Transition-metal-catalyzed alkene hydrosilylation is one of the most important homogeneous catalytic reactions, and the development of methods that use base metals, especially iron, as catalysts for this transformation is a growing area of research. However, the limited number of ligand scaffolds applicable for base-metal-catalyzed alkene hydrosilylation has seriously hindered advances in this area. Herein, we report the use of 1,10-phenanthroline ligands in base-metal catalysts for alkene hydrosilylation. In particular, iron catalysts with 2,9-diaryl-1,10-phenanthroline ligands exhibit unexpected reactivity and selectivity for hydrosilylation of alkenes, including unique benzylic selectivity with internal alkenes, Markovnikov selectivity with terminal styrenes and 1,3-dienes, and excellent activity toward aliphatic terminal alkenes. According to the mechanistic studies, the unusual benzylic selectivity of this hydrosilylation initiates from π-π interaction between the phenyl of the alkene and the phenanthroline of the ligand. This ligand scaffold and its unique catalytic model will open possibilities for base-metal-catalyzed hydrosilylation reactions.
ABSTRACT
OBJECTIVE: To investigate the acceptability and influential factors of Voluntary HIV Counseling and Testing (VCT) among the Chinese and Ethiopian peacekeepers in Liberia so as to conduct more effective health education of AIDS and enhance the acceptance of VCT. METHODS: An anonymous questionnaire was used to investigate the attitudes to VCT among 518 Chinese (aged 23-51) and 648 Ethiopian (aged 25-49) peacekeepers in Liberia. RESULTS: The rates of those who claimed to have never heard of HIV/AIDS were 8.1% and 7.9% in the Chinese and Ethiopian subjects respectively, with no significant differences (P > 0.05) in between. Among those who had heard of HIV/ AIDS, 407 (85.5%) Chinese and 449 (75.2%) Ethiopians expressed their willingness to accept VCT, with a significant difference (P < 0.05) between the two groups. Statistic analysis indicated that the acceptance of VCT was as- sodiated with schooling and knowledge on HIV/AIDS in both groups as well as with the susceptibility to HIV among the Ethiopian subjects. CONCLUSION: The acceptability of VCT is obviously lower among those with less schooling and less knowledge of HIV/AIDS. It is important to carry out information-oriented education to increase VCT acceptability among the peacekeepers in the area with a high incidence of AIDS.
Subject(s)
Health Knowledge, Attitudes, Practice , Military Personnel/psychology , Surveys and Questionnaires , Acquired Immunodeficiency Syndrome/prevention & control , China , Counseling/methods , Counseling/statistics & numerical data , Ethiopia , Humans , Liberia , Male , Mass Screening/methods , Mass Screening/psychology , Mass Screening/statistics & numerical dataABSTRACT
OBJECTIVE: To investigate and analyze AIDS knowledge of the Chinese peacekeepers in Liberia and to evaluate the effects of AIDS education in order to conduct more effective health education of AIDS and increase AIDS knowledge among the Chinese peacekeepers in the areas with a high incidence of AIDS. METHODS: A questionnaire was designed on the basis of that recommended by WHO to investigate the knowledge of AIDS among the 528 Chinese peacekeepers in Liberia respectively before and after relevant health education, and the results were compared. RESULTS: There was an obvious deficiency in AIDS knowledge among the subjects before the education and an evident increase after it, and the difference was significant (P <0.01). CONCLUSION: The Chinese peacekeepers are deficient in AIDS knowledge, and the deficiency can be effectively improved by relevant health education, which is essential for the health of the Chinese peacekeepers in the areas with a high incidence of AIDS.
