Biomedical subjects

R Xiong

Publications and source records attributed to R Xiong.

4 recordsLinked to original sources

PubMed1999

A mathematical model for bacterial inactivation.

The first order kinetic model, the Buchanan model and Cerf's model, can model a linear survival curve, a survival curve with a shoulder and a survival curve with a tailing, respectively. However, they are not suitable for fitting a sigmoidal survival curve. The three models were integrated into a new model that was capable of fitting the four most commonly observed survival curves: linear curves, curves with a shoulder, curves with a tailing (biphasic curves) and sigmoidal curves. The new model was compared with the Whiting-Buchanan model using the survival curves of Staphylococcus aureus. The goodness-of-fit of the proposed model is practically as good as that of the Whiting-Buchanan model. Compared with the Whiting-Buchanan model, the proposed model has a more mechanistic background. Since for non-linear survival curves, such as biphasic and sigmoidal curves, the t(m-D) value (the time required for an m-log-cycle reduction of microorganisms under a given condition) cannot be estimated accurately by the existing or traditional method, a new method is also proposed to predict accurately the t(m-D) value for non-linear survival curves.

Food Microbiology↗

PubMed1999

The fate of Salmonella enteritidis PT4 in home-made mayonnaise prepared with citric acid.

The fate of Salmonella enteritidis PT4 in home-made mayonnaise prepared with citric acid solution (citric acid concentration of > or = 4.98% (w/v)) was investigated. It was found that pH of mayonnaise is closely related to the ratio of egg yolk to citric acid, and the inactivation rate of the micro-organisms increases as the ratio decreases and/or incubation temperature increases. To achieve Salm. enteritidis PT4-free home-made mayonnaise prepared with pure lemon juice (citric acid concentration > or = 5% (w/v)), it is recommended that the pH should be 3.30 or below, or, in practice, at least 20 ml pure lemon juice per fresh egg yolk should be used. For the use of 20-35 ml pure lemon juice per egg yolk, the product should be held at 22 degrees C or over for at least 72 h and for the use of over 35 ml pure lemon juice per egg yolk, for at least 48 h before consumption or refrigeration.

Citric Acid↗

PubMed1998

[The food habit and its affecting factors of preschool children in Guangzhou].

A survey of nutritional knowledge-attitude-practice was conducted among 1300 preschool children, their parents, 203 teachers and nurses in Kindergarten in 1997. Results showed that the food habit of preschool children was unsuitable. Most preschool children rejected eating animal liver, peanut product and animal blood, but often ate snacks. From statistic analysis among affecting factors, the mother's and teachers' nutritional knowledge and the food habit of parents had significant effect on food habit of preschool children. The family income did not significantly affect food habit of preschool children. Moreover, there was little nutrition education involved in the preschool children courses in 4 kindergartens. The result suggested that the nutrition education plan should be done.

Adult↗

PubMed1992

Clinical significance of flow cytometric deoxyribonucleic acid measurements of deparaffinized specimens in bladder tumors.

A retrospective study of flow cytometric measurements on paraffin-embedded tumor specimens from 188 patients with bladder tumor was conducted. Results were analyzed in combination with the morphological variation in bladder tumors. It was found that the deoxyribonucleic acid (DNA) ploidy pattern, the degree of infiltration and the multiplicity of bladder tumor were closely related with tumor recurrence, among which the DNA ploidy pattern was most significant. In aneuploid bladder tumors, the recurrence rate and the mean annual recurrence frequency were 76.7% and 1.46, respectively, and in the diploid bladder tumors, they were 18.7% and 0.33, respectively. Aneuploidy was the most indicative parameter of recurrence in bladder tumors. In addition, according to the DNA content and the ploidy level of the aneuploid cell lines, the aneuploid tumors in our group were divided into four types, namely tetraploid tumors, noneuploid tumors with an DNA index (DI) less than or equal to 1.5, hypotetraploid tumors and aneuploid tumors with several cell lines. The results showed that the recurrence rate of tetraploid tumors was relatively lower, and it became higher and higher in the following order: noneuploid tumors with DI less than or equal to 1.5, noneuploid tumors with DI greater than 1.5, and two-aneuploid tumors. This indicates that there are different biological behaviors in tumors with different ploidy patterns. Finally, the correlation between the DNA ploidy pattern and tumor metastases was also discussed.

Carcinoma, Transitional Cell↗