Photoinduced nucleation of water vapor.

Strong photoinduced nucleation of pure water vapor was found to occur in a wavelength range where no ultraviolet absorption of water vapor has been reported. Systematic studies were made of the dependence of the nucleation rate and the delay time for the initiation of nucleation on light intensity. The results obtained were accurately fitted by a phenomenological mechanism whereby the nucleation is initiated by clusters accumulating an appropriate number of photoexcited water molecules.

Nucleation on photoexcited molecules.

On irradiation with light of suitable wavelength and intensity, certain organic compounds, even at very low concentrations, cause very efficient nucleation of supersaturated vapors. A mechanism is suggested to account for this phenomenon. Nuclei containing only a few photoexcited molecules are responsible for the nucleation.

[An preliminary comparative study on physiological activity of Fritillaria pallidiflora Schrek. and F. delavayi Franch].

OBJECTIVE: To compare the physiological activity of Fritillaria pallidiflora alkaloids(FPA) with that of F. delavayi alkaloids(FDA). METHOD: Xylene-induced ear swelling in mice, SO2-induced cough in mice, expectorant experiment on phenolsulfon phthalein excretion and bacteria incubation in vitro, etc. RESULT: The total alkaloids of both FPA and FDA(i.g., 400 mg.kg-1 and 200 mg.kg-1) have anti-inflammatory, antibechic and expectorant effects, but the former is more effective than the latter. Given the same dosage, FPA is still more effective than FDA. FPA can inhibit Hemophilus influenzae, Staphylococcus aureus and Streptococcus pneumoniae, etc, more effectively than FDA. CONCLUSION: In anti-inflammatory, antibechic, expectorant and bacteriostatic effects FPA is superior to FDA.

Analysis of trinucleotide repeats in different SCA loci in spinocerebellar ataxia patients and in normal population of Taiwan.

OBJECTIVE: To identify various subtypes of spinocerebellar ataxias (SCAs) among autosomal dominant cerebellar ataxia (ADCA) patients referred to our research center, SCA1, SCA2, SCA3/MJD (Machado-Joseph disease), SCA6, SCA7, SCA8 and SCA12 loci were assessed for expansion of trinucleotide repeats. PATIENTS AND METHODS: A total of 211 ADCA patients, including 202 patients with dominantly inherited ataxia from 81 Taiwanese families and nine patients with sporadic ataxia, were included in this study and subjected to polymerase chain reaction (PCR) analysis. The amplified products of all loci were analyzed on both 3% agarose gels and 6% denaturing urea-polyacrylamide gels. PCR-based Southern blots were also applied for the detection of SCA7 locus. RESULTS: The SCA1 mutation was detected in six affected individuals from one family (1.2%) with expanded alleles of 50-53 CAG repeats. Fourteen individuals from nine families (11%) had a CAG trinucleotide repeat expansion at the SCA2 locus, while affected SCA2 alleles have 34-49 CAG repeats. The SCA3/MJD CAG trinucleotide repeat expansion in 60 affected individuals from 26 families (32%) was expanded to 71-85 CAG repeats. As for the SCA7 locus, there were two affected individuals from one family (1.2%) possessed 41 and 100 CAG repeats, respectively. However, we did not detect expansion in the SCA6, SCA8 and SCA12 loci in any patient. CONCLUSIONS: The SCA3/MJD CAG expansion was the most frequent mutation among the SCA patients. The relative prevalence of SCA3/MJD in Taiwan was higher than that of SCA2, SCA1 and SCA7.