By the techniques of far-infrared optically detected cyclotron resonance and magnetophotoconductivity, we have performed cyclotron-resonance measurements on relaxed In Ga& As epitaxial layers with a wide range of composition. The measured electron effective mass as a function of indium composition has been analyzed with the five-band k p calculation. It is found that the effect of disorder-induced conductionvalence-band mixing must be included in order to resolve the discrepancy between the results of the k p theory and experiments. The linewidths of cyclotron resonance and photoluminescence as a function of alloy composition have also been studied. Comparing with the measurement of doublecrystal x-ray diffraction, we point out that the cyclotron-resonance and photoluminescence signals in In"oa& As alloys are dominated by the dislocation scattering. In addition, we show that the quality of a ternary epilayer is not only influenced by the lattice mismatch; the surface migration lengths of the cation atoms in the initial growth stage also play a very important role.

ABSTRACT. Like other developing countries, China was reported to have a relatively high seroprevalence of anti-hepatitis A antibodies (anti-HAV). However, no studies have evaluated the prevalence of anti-HAV and HAV RNA among voluntary blood donors with or without elevated serum alanine transaminase (ALT) levels. Anti-HAV antibodies were detected using an enzyme-linked immunosorbent assay, and reverse transcription quantitative polymerase chain reaction was carried out for detection of HAV RNA. In the current study, we analyzed a total of 450 serum samples with elevated ALT levels (≥40 U/L) and 278 serum samples with non-elevated ALT levels. Seroprevalence rates of anti-HAV were 51.6% in donors with elevated ALT and 41.4% in donors with non-elevated ALT; however, none of the samples was positive for HAV RNA. The results of our study showed lower seroprevalence rates of anti-HAV in blood donors (irrespective of ALT levels) than those in published data on Chinese populations. Although donors with elevated ALT had statistically higher prevalence rates of anti-HAV than did those with non-elevated ALT, none of the serum samples had detectable levels of the active virus. In conclusion, our results demonstrate that the transmission of hepatitis A by blood transfusion will occur rarely.

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