Kinetics and variation of volatile components of Atractylodis Macrocephalae Rhizoma during hot-air drying / 中国中药杂志

The present study explored the kinetics and variation of volatile components of Atractylodis Macrocephalae Rhizoma during the hot-air drying process to obtain the optimal process parameters under multiple goals such as drying efficiency and drying quality. The dry basis moisture content and drying rate curves along with the change of drying time of Atractylodis Macrocephalae Rhizoma were investigated at five levels of drying air temperatures(30, 40, 50, 60, and 70 ℃). The relationship between moisture ratio and time in the drying process of Atractylodis Macrocephalae Rhizoma was fitted and verified by Midilli model, Page model, Overhults model, Modified Page model, Logaritmic model, Two terms Exponential model, and Newton model. Meanwhile, the effective diffusion coefficient of moisture(D_(eff)) and activation energy(E_a) in Atractylodis Macrocephalae Rhizoma were calculated under different drying air temperatures. GC-MS was used to determine the volatile components and content changes of the fresh Atractylodis Macrocephalae Rhizoma and dried products at different temperatures. The dry basis moisture content and drying rate of Atractylodis Macrocephalae Rhizoma were closely related to the temperature of the drying medium, and the moisture of the Atractylodis Macrocephalae Rhizoma decreased with the prolonged drying time. As revealed by the drying rate curve, the drying rate increased with the increase in hot air temperature, and the migration of moisture was accelerated. The comparison of the correlation coefficient(R~2), chi-square(χ~2), and root mean standard error(RMSE) of each model indicated that the parameter average of the Midilli model had the highest degree of fit, with R~2=0.999 2, χ~2=8.78×10~(-5), and RMSE=8.20×10~(-3). Besides, the D_(eff) at 30-70 ℃ was in the range of 1.04×10~(-9)-6.28×10~(-9) m~2·s~(-1), and E_a was 37.47 kJ·mol~(-1). The volatile components of fresh Atractylodis Macrocephalae Rhizoma and dried products at different temperatures were determined by GC-MS, and 18, 18, 18, 17, 17, and 18 compounds were identified respectively, which accounted for more than 84.76% of the volatile components. In conclusion, the hot-air drying of Atractylodis Macrocephalae Rhizoma can be model-fitted and verified and the variation law of the moisture and volatile components of Atractylodis Macrocephalae Rhizoma with temperature is obtained. This study is expected to provide new ideas for exploring the drying characteristics and quality of aromatic Chinese medicine.

Simulation of industrial fermentation: current status and future perspectives / 生物工程学报

Industrial fermentation is the basic operation unit of industrial biotechnology in large-scale production. Mathematical simulation of microbial cells and their reactors will help deepen the understanding of microorganisms and fermentation processes, and will also provide solutions for the construction of new synthetic organisms. In this paper, the characteristics of industrial fermentation system, the development of mathematical simulation, the classification, characteristics and functions of mathematical models are described in depth, and the development trend of whole fermentation system simulation is prospected.

Discussion on evaluation mode of proficiency testing for heavy metal and harmful element detection in medicines / 中国中药杂志

This study aims to explore the evaluation model for the proficiency testing of heavy metal and harmful element residues in pharmaceuticals,and to provide reference for the proficiency testing program and proficiency testing result in the field of residue analysis. The proficiency test result of cadmium determination in honeysuckle as an example. The algorithm A,NIQR,and Horwitz function are used to calculate the assigned value and the standard deviation. Z was obtained at the same time. If | Z | ≤2,the result is satisfactory. If 2< | Z | <3,the result is questionable. If | Z | ≥3,the result is unsatisfactory. In addition,the median value is the assigned value,and deviation(D%) is used. If D% is not more than 16%,the result is satisfactory; if D% is more than 16%,the result is unsatisfactory. After analysis,in the results of questionable or dissatisfied laboratories calculated by algorithm A and NIQR,the deviation error of some data is within the scope of the standard. In the results of the satisfactory laboratory evaluated by the Horwitz function,some data deviation errors far exceed the standard range. The evaluation result of the D% meets the requirements. According to heavy metal and harmful element trace analysis methods,this study is the first to apply D% to the evaluation of the detection ability of heavy metals and harmful elements in pharmaceuticals. This method makes the evaluation result more reasonable,and has important reference significance for the evaluation of other proficiency test results.

Drying kinetics and mathematical modeling of Erzhi Pills during hot-air drying process / 中草药

Objective: To study the change rule of water content in the drying process of hot air drying of thin layer drying characteristic and model research, and to provide reference for improving the quality of Erzhi Pills (EP). Methods: The moisture ratio, drying rate of dry basis, and drying rate curves along with the change of drying time and relationship between dry basis moisture content and drying rate of EP were studied using a hot air dryer at five levels of drying air temperature in the range of 50-90 ℃. The model was fitted and verified by the empirical model Henderson & Pabis model, Newton model, Page model, Logarithmic model, two term exponential model, Wang & Singh model, Midilli et al. model, etc. Meanwhile, based on Fick's diffusion law, the effective diffusion coefficients of water (Deff) and activation energy value in EP were calculated. Results: The drying curves of EP show that the moisture ratio and drying rate of EP were closely related to the temperature of drying medium, and the moisture of the material decreases with the prolonged drying time. It could be seen from the drying rate curve that the drying rate increased with the increase of hot air temperature, and the migration of moisture was accelerated. By comparing the correlation coefficient (R2), chi-square (χ2) and standard error (RMSE), we could see that the mean value of R2 of model number 7 was the maximum, the χ2 and RMSE mean were the smallest (0.996 86, 2.43 × 10−4, and 1.93 × 10−4), respectively. The results showed that the model number 7 could describe and predict the drying process of the pills. The experimental data had the effective diffusion coefficient (Deff) value of 8.6 × 10−11—3.13 × 10−10 m2/s, and the activation energy (Ea) was 30.97 kJ/mol. Conclusion: The hot air drying process of EP can be modeled and verified. The research provides a new way to explore the drying characteristics and quality of pills.

Empirical model for estimating dengue incidence using temperature, rainfall, and relative humidity: a 19-year retrospective analysis in East Delhi / 한국역학회지

OBJECTIVES: Aedes mosquitoes are responsible for transmitting the dengue virus. The mosquito lifecycle is known to be influenced by temperature, rainfall, and relative humidity. This retrospective study was planned to investigate whether climatic factors could be used to predict the occurrence of dengue in East Delhi. METHODS: The number of monthly dengue cases reported over 19 years was obtained from the laboratory records of our institution. Monthly data of rainfall, temperature, and humidity collected from a local weather station were correlated with the number of monthly reported dengue cases. One-way analysis of variance was used to analyse whether the climatic parameters differed significantly among seasons. Four models were developed using negative binomial generalized linear model analysis. Monthly rainfall, temperature, humidity, were used as independent variables, and the number of dengue cases reported monthly was used as the dependent variable. The first model considered data from the same month, while the other three models involved incorporating data with a lag phase of 1, 2, and 3 months, respectively. RESULTS: The greatest number of cases was reported during the post-monsoon period each year. Temperature, rainfall, and humidity varied significantly across the pre-monsoon, monsoon, and post-monsoon periods. The best correlation between these three climatic factors and dengue occurrence was at a time lag of 2 months. CONCLUSIONS: This study found that temperature, rainfall, and relative humidity significantly affected dengue occurrence in East Delhi. This weather-based dengue empirical model can forecast potential outbreaks 2-month in advance, providing an early warning system for intensifying dengue control measures.

Comparing and Modifying Eight Empirical Models of Snowmelt Using Data from Harp Experimental Station in Central Ontario.

Aims: To modify two empirical models of snowpack and snowmelt, and compare eight such models. Study Design: Test and modify the models by using five years of snow measurements from Harp Lake. Place and Duration of Study: Dorset Environmental Science Centre, Ontario Ministry of Environment, and Department of Geography, Nipissing University, between January 2009 and August 2012. Methodology: The old daily-run WINTER model was the first model. It was modified to create a second model. The enhanced-temperature-index (ETI) model was slightly modified to be the third model. Modified WINTER and ETI were combined into the fourth model. Hydrology model BROOK90 and SWAT were used as the fifth and sixth model, also daily-run. Operating the WINTER and ETI in hourly steps created the seventh and eighth model. The calculated snow water equivalent (SWE) by each model was evaluated against the observed data to give a coefficient of efficiency (CE). Accuracy and performance of the models were compared based on CE values. Results: Modified WINTER model improved original WINTER by 20.7% (CE increased 20.7%). The performance of ETI model was 27.6% higher than the original WINTER. The new combination model produced additional improvement by 40.7 % over the original WINTER, or by 16.5% over the modified WINTER or 10.3% over the ETI. Running the model with hourly time steps rather than daily steps increased model’s accuracy: hourly WINTER raised CE by 15.4% and hourly ETI raised CE by 7.9%. Two watershed hydrology models BROOK90 and SWAT performed even better than the above six simpler snow models. Conclusion: It is suggested that the daily combination model be considered if only daily data is available, or hourly WINTER and ETI models be used if hourly runs are desired while new calibration are required when applying them to any new locations. If data requirements by BROOK90 or SWAT are met, these hydrology models would be tried.