Search for serendipitous TNO occultation in X-rays

To study the population properties of small, remote objects beyond Neptune's orbit in the outer solar system, of kilometer size or smaller, serendipitous occultation search is so far the only way. For hectometer-sized Trans-Neptunian Objects (TNOs), optical shadows actually disappear because of diffraction. Observations at shorter wave lengths are needed. Here we report the effort of TNO occultation search in X-rays using RXTE/PCA data of Sco X-1 taken from June 2007 to October 2011. No definite TNO occultation events were found in the 334 ks data. We investigate the detection efficiency dependence on the TNO size to better define the sensible size range of our approach and suggest upper limits to the TNO size distribution in the size range from 30 m to 300 m. A list of X-ray sources suitable for future larger facilities to observe is proposed.Comment: Accepted to publish in MNRA

Comparison of Renal Function and Other Health Outcomes in Vegetarians versus Omnivores in Taiwan

Renal disease is one of the top 10 leading causes of death, and the incidence of end-stage renal disease in Taiwan is the highest in the world. Many dietitians consider the diet of plant origin consumed by vegans to be ‘lighter’ and ‘more healthful’ than the diet of both plant and animal origin consumed by omnivores. Dietary protein has significant effects on renal functions. The study explored the effects of both the diets on renal functions. The study subjects included 102 Buddhist nun vegetarians and an equal number of matched control group (omnivores). A cross-sectional study was performed to investigate the effects of the diet of plant origin and the diet of both plant and animal origin on renal functions. There was no difference in the renal functions between the two groups. However, systolic blood pressure, blood urea nitrogen, serum sodium, glucose, cholesterol levels, and urinary specific gravity were lower in the vegetarian group. Although these results were compatible with general concepts regarding diet of plant origin, after adjusting for age, the duration of intake of this diet had no effect on the renal functions. Based on the findings, it is concluded that the renal functions, in terms of the estimated glomerular filtration rate, were not different between the vegetarians and the omnivores

Therapeutic protein expression platform of microbial system

A number of expression systems have been developed for the production of pharmaceutical products. Pichia pastoris and Escherichia coli expression system operate in our lab and express antibody fragment (scFv), cytokine, protein base adjuvant and vaccine and process enzyme. The expression platform are consisted of three part, first is strain generation , the second is fermentation process development in 250 ml fermentor and the last is process scale-up to 5 litter fermentor. Please click Additional Files below to see the full abstract

The microbial antibodies secretion expression platform with scale down fermentors

Therapeutic antibodies have become one of the most effective therapeutics for human diseases such as cancer, inflammation and viral infection. The production of antibody-based drugs using microbial expression systems is more cost effective with ease of gene manipulation compared to mammalian expression systems. In our team, antibody fragments (ex: BsAb, scFv and Fab) were produced from methylotrophic yeast Pichia pastoris secretion expression system with the AOX1 as driven promoter or E. coli secretion expression system. To achieve high production yield for both system, we investigated fermentation parameter such as base medium, induction medium, induction condition, feeding strategy and pH. For the 250 ml fermentor Pichia system, the nitrogen have been add into glycerol fed medium and/or methanol induction medium and also compared base-medium, buffered glycerol-complex medium (BMGY) and basal salt medium (BS). The highest scFv production was yielded from the basal salt medium as base medium, glycerol fed medium plus nitrogen and multiple carbon source methanol induction medium. This process can yielded over 500 mg/L scFv. After scale-up from 250 ml fermentor to 5L fermentor, the methanol fed-back control system also applied on the 5 L fermentor, can achieve 1.7 g/L scFv in 5 days. The E. coli expression process has passed through screening for high production yield clones in 2 ml deep-well then confirmed by using 250 ml flask scale. Feeding medium, DO, pH etc, parameters were investigated by parallel 250 ml-fermenter. The parameters from 250 ml fermentor were validated by using 5 L fermenter. Under this scale-up procedure, the antibody Fab was 100 folds production yield, production deep well stage at 1 mg/L, production from 250 ml fermentor stage is 50-100 mg/L and production 5 L fermentor stage is over 35-90 mg/L. Although different antibodies will result in different production yield, building a reliable platform to predict production yield from antibody cell clones under deep well and shake flask stage serves a good scale-down model for future scale-up prediction

Engineering of Escherichia coli protein expression process development

It almost 30% protein drugs are expression by Escherichia coli, because of rapid growth and high production yield. We have developed E.coli base system for recombinant protein expression, scFv, Fab and vaccine. In this study we introduce example about process development for nutrient components selection. Shaker flasks were used for different nitrogen and carbon components screening by DoE. Seven media formulations for E. coli fermentation were used in this study. By changing nitrogen and carbon source ratio, product titer of target protein could be optimized, at least 1.4 folds increased. The best result from shaker flask was used in 250 mL parallel fermenter and pH, dissolved oxygen, feeding/induction strategy were evaluated. The processes from seed culture to harvest only require 64 hours. The optimized time was reduced to 32 hours. The result showed that both target protein expression and cell density value were comparable, but the total process time was significantly reduced by half Please click Additional Files below to see the full abstract

Application and comparison of scoring indices to predict outcomes in patients with healthcare-associated pneumonia

Introduction: Healthcare-associated pneumonia HCAP is a relatively new category of pneumonia. It refers to infections that occur prior to hospital admission in patients with specific risk factors following contact or exposure to a healthcare environment. There is currently no scoring index to predict the outcomes of HCAP patients. We applied and compared different community acquired pneumonia CAP scoring indices to predict 30-day mortality and 3-day and 14-day intensive care unit ICU admission in patients with HCAP. Methods: We conducted a retrospective cohort study based on an inpatient database from six medical centers, recruiting a total of 444 patients with HCAP between 1 January 2007 and 31 December 2007. Pneumonia severity scoring indices including PSI pneumonia severity index, CURB 65 confusion, urea, respiratory rate, blood pressure , age 65, IDSA/ATS Infectious Diseases Society of America/American Thoracic Society, modified ATS rule, SCAP severe community acquired pneumonia, SMART-COP systolic blood pressure, multilobar involvement, albumin, respiratory rate, tachycardia, confusion, oxygenation, pH, SMRT- CO systolic blood pressure, multilobar involvement, respiratory rate, tachycardia, confusion, oxygenation, and SOAR systolic blood pressure, oxygenation, age, respiratory rate were calculated for each patient. Patient characteristics, co-morbidities, pneumonia pathogen culture results, length of hospital stay LOS, and length of ICU stay were also recorded. Results: PSI > 90 has the highest sensitivity in predicting mortality, followed by CURB-65 >= 2 and SCAP > 9 SCAP score area under the curve AUC: 0.71, PSI AUC: 0.70 and CURB-65 AUC: 0.66. Compared to PSI, modified ATS, IDSA/ATS, SCAP, and SMART-COP were easy to calculate. For predicting ICU admission Day 3 and Day 14, modified ATS AUC: 0.84, 0.82 , SMART-COP AUC: 0.84, 0.82, SCAP AUC: 0.82, 0.80 and IDSA/ ATS AUC: 0.80, 0 .79 performed better statistically significant difference than PSI, CURB- 65, SOAR and SMRT-CO. Conclusions: The utility of the scoring indices for risk assessment in patients with healthcare-associated pneumonia shows that the scoring indices originally designed for CAP can be applied to HCAP