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We systematically investigated the correlation between morphological and optical properties ofInGaAs self-assembled quantum dots (QDs) grown by solid-source molecular beam epitaxy on GaAs(n 11)B(n = 9, 8, 7, 5, 3, 2) substrates. Remarkably, all InGaAs QDs onGaAs(n 11)B under investigation show optical properties superior to those forones on GaAs(100) as regards the photoluminescence (PL) linewidthand intensity. The morphology for growth of InGaAs QDs on GaAs(n 11)B,where n = 9, 8, 7, 5, is observed to have a rounded shape with a higher degree of lateral ordering thanthat on GaAs(100). The optical property and the lateral ordering are best for QDs grownon a (511)B substrate surface, giving a strong correlation between lateral ordering and PLoptical quality. Our results demonstrate the potential for high quality InGaAs QDs onGaAs(n 11)B for optoelectronic applications. [ABSTRACT FROM AUTHOR]

In 1972 a nonsocomial outbreak of parenterally transmitted hepatitis affected both marrow transplant patients and normal platelet donors in an oncology unit. Because of the characteristics of the clinical illness, the incubation period of 27 days, and the effect of immune serum globulin on the clinical illness, the outbreak was attributed to hepatitis A; there was no serologic evidence of either hepatitis B virus or cytomegalovirus infection. Stored serums from this outbreak were re-examined by more recently developed serologic techniques for evidence of hepatitis A (HA) virus infection. Ten patients and donors had undetectable anti-HA titers before illness and none seroconverted; five persons had pre-existent anti-HA titers and showed no further rise in convalescent serums. The serum of one patient was inevaluable. With the availability of serologic techniques for the diagnosis of both hepatitis A and hepatitis B virus infections, it is clear that most cases of post-transfusion hepatitis are not due to either of these agents, and short-incubation-period hepatitis can not be assumed to be hepatitis A without further investigation. [ABSTRACT FROM AUTHOR]

Background Cervical cancer, although usually preventable by Pap smear screening, remains the leading cause of cancer-related deaths among women in Peru. The percentages and characteristics of women in Peru who have or have not had a Pap smear have not been defined. Methods In an urban community randomized trial of sexually transmitted infection (STI)/HIV prevention in Peru, 6712 randomly selected women between the ages of 18 and 29 from 20 cities were interviewed regarding having had cervical Pap smears. Results Among women sampled, only 30.9% had had a Pap smear. By multivariate analysis, the main predictors of having a Pap smear were having had sex, having had children, completion of secondary education and increasing age. Regional variations were also found: women from the highlands and rainforest were less likely to have had Pap smears than women from the coast. Conclusion A norm of seeking and receiving Pap smears has not been established among sexually active young Peruvian women. To improve Pap smear coverage in Peru, promotion efforts should target underserved women and regions with less coverage. [ABSTRACT FROM AUTHOR]