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Biomedical subjects

P Y Su

Publications and source records attributed to P Y Su.

6 recordsLinked to original sources
PubMed2002

Structural evolution in amorphous silicon and germanium thin films.

The structural evolution in amorphous silicon and germanium thin films has been investigated by high-resolution transmission electron microscopy (HRTEM) in conjunction with autocorrelation function (ACF) analysis. The results established that the structure of as-deposited semiconductor films is of a high density of nanocrystallites embedded in the amorphous matrix. In addition, from ACF analysis, the structure of a-Ge is more ordered than that of a-Si. The density of embedded nanocrystallites in amorphous films was found to diminish with annealing temperature first, then to increase. The conclusions also corroborate well with the results of diminished medium-range order in annealed amorphous films determined previously by a variable coherence microscopy method.

Alloys↗
PubMed1997

Ty3/gypsy-like retrotransposon sequences in tomato.

Polymerase chain reactions (PCRs) were carried out with DNAs of eight tomato species using primers directed at the reverse transcriptase domain of Ty3/gypsy-like LTR retrotransposons. All DNAs gave PCR products of the expected size which, after cloning and sequencing, were confirmed as representing Ty3/gypsy-like elements. The sequences were heterogeneous, only 3 of the 16 being identical and the most diverse showing 124/426 pairwise nucleotide differences. Multiple alignment and construction of neighbor joining trees divided the sequences into six groups, three comprising five, three, and five sequences respectively, and the other three containing a single sequence each.

Amino Acid Sequence↗
PubMed1996

Hepatitis delta antigens enhance the ribozyme activities of hepatitis delta virus RNA in vivo.

The mechanism of regulation for the ribozyme activity of hepatitis delta virus (HDV) RNA in infected cells is unknown. Previously, we developed a direct assay capable of detecting the ribozyme activity of HDV dimer or trimer RNAs in vivo (K.-S. Jeng, A. Daniel, and M. M. C. Lai, J. Virol, 70:2403-2410, 1996). In this study, we used this method to examine the effects of hepatitis delta antigen (HDAg) on the ribozyme activities of HDV RNA in vivo. The HDV multimer cDNAs were cotransfected with plasmids encoding either HDV small delta antigen (SHDAg) or large delta antigen (LHDAg), and the self-cleavage of the primary transcripts from the HDV cDNA was analyzed at day 2 postransfection. The results were as follows. (i) Both HDAgs, particularly LHDAg, enhanced the self-cleavage activity of HDV RNA; however, HDAgs are not required for HDV RNA cleavage. (ii) HDAg could not restore the ribozyme activity of mutant HDV RNAs which have lost the ribozyme function. (iii) The enhancement of ribozyme activity by HDAg does not require HDV RNA replication. (iv) RNA-binding activity of HDAg is required for the enhancement of RNA cleavage. (v) The self-ligation activities of HDV ribozyme also were enhanced by HDAg. These results suggest that HDAg can regulate the cleavage and ligation of HDV RNA during the HDV life cycle.

Cell Line↗
PubMed1989

Surgical treatment of bleeding and perforated peptic ulcer diseases.

From 1977 to 1988, 556 patients underwent emergency surgery for complicated peptic ulcers. Among them, 409 patients were for treated perforations and 147 for hemorrhages. In the perforated ulcer category, the morbidity rate was 12.5% and mortality rate 6.8%. For bleeding ulcers, the morbidity rate was 27.2% and mortality rate 14.9%. Several risk factors, such as age, interval of time between perforation and surgery, blood loss, associated disease, and shock were found to have created a higher operative risk. A definitive surgery including vagotomy and drainage, vagotomy and antrectomy, partial gastrectomy and highly selective vagotomy could be safely performed with an acceptable mortality for properly selected cases. Follow-up results also indicated better scores in this group of patients. We concluded that a definitive ulcer operation is safe, acceptable and curative for low risk patients with perforated or bleeding ulcers.

Adult↗
PubMed1985

Replantation of the testis by microsurgical technique.

Microsurgical replantation of amputated testes were performed in two patients. Both were caused by trauma to the genitoperineal regions. These reconstructed testes are viable and not atrophic grossly. The patients are satisfied with these operations.

Adult↗