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Background/Objectives: Numerical simulation plays an important role in pharmaceutical preparation recently. Mechanistic models, as a type of numerical model, are widely used in the study of pharmaceutical preparations. Mechanistic models are based on a priori knowledge, i.e., laws of physics, chemistry, and biology. However, due to interdisciplinary reasons, pharmacy researchers have greater difficulties in using computer models. Methods: In this paper, we highlight the application scenarios and examples of mechanistic modelling in pharmacy research and provide a reference for drug researchers to get started. Results: By establishing a suitable model and inputting preparation parameters, researchers can analyze the drug preparation process. Therefore, mechanistic models are effective tools to optimize the preparation parameters and predict potential quality problems of the product. With product quality parameters as the ultimate goal, the experiment design is optimized by mechanistic models. This process emphasizes the concept of quality by design. Conclusions: The use of numerical simulation saves experimental cost and time, and speeds up the experimental process. In pharmacy experiments, part of the physical information and the change processes are difficult to obtain, such as the mechanical phenomena during tablet compression and the airflow details in the nasal cavity. Therefore, it is necessary to predict the information and guide the formulation with the help of mechanistic models. [ABSTRACT FROM AUTHOR]

Based on dividing institutional difference into formal institutional difference and informal institutional difference, this study explores the impact of institutional difference on scientific collaboration of six provinces in central China and analyses the moderating effect of provincial innovation environment and provincial research and development capacity using panel data from 2010 to 2019. The study finds that both formal institutional difference and informal institutional difference negatively affect scientific collaboration of six provinces in central China. Moreover, provincial innovation environment and provincial research and development capacity moderate the relationship between institutional difference and scientific collaboration of six provinces in central China. That is, in the context of good provincial innovation environment or high research and development capacity, the negative impact of institutional difference on scientific collaboration of six provinces in central China is stronger. [ABSTRACT FROM AUTHOR]

By using the involute gears instead of the cycloid pin gears in the RV reducer,a 2K- V involute planetary gear reducer is redesigned,and a three dimensional model of the reducer is established. The static contact simulation of the internal meshing which is a key part of the reducer is proceeded by the finite element analysis software ABAQUS. Then,the meshing tooth pairs and the load distribution are obtained and compared with the results of theoretical calculation. A further comparing of contact load and the elastic meshing effect coefficient under different torque is conducted. Finally,considering the influence of gear frictional heat,a steady- state coupled contact simulation under rated torque is carried out,the temperature field distribution and the thermal stress distribution of the tooth are obtained,the reliability of the gear contact characteristic is proved.

Maytansine (DM1) is a potent anticancer drug and limited in clinical application due to its poor water solubility and toxic side effects. Zein is widely used in nano drug delivery systems due to its good biocompatibility. In this study, we prepared DM1-loaded zein nanoparticles (ZNPs) to achieve tumor targeting and reduce toxic side effects of DM1. Methods: ZNPs were prepared by phase separation and Box-Behnken design was used to optimize the formulation. Then, confocal fluorescence microscope and flow cytometry were used to determine cellular uptake of ZNPs. A549 cells were cultured in vitro to study cytotoxicity and used to establish tumor xenografts in nude mice. Biodistribution and antitumor activity of ZNPs were performed in vivo experiments. In addition, we also performed histological and immunohistochemical examinations on tumors and viscera. Results: The optimal prescription was obtained by using 120 μL zein added to 2 mL water under stirring in 300 rpm. The encapsulation efficiency and drug loading were 82.97 ± 0.80% and 3.32 ± 0.03%, respectively. We found that DM1-loaded ZNPs have a strong inhibitory effect on A549 cells, which stemmed from the ability of ZNPs to enhance cellular uptake. Furthermore, we demonstrated that DM1-loaded ZNPs exhibits a better antitumor efficacy than DM1, which tumor inhibition rate were 97.3% and 92.7%, respectively. The biodistribution revealed that ZNPs could targeted to tumor. Finally, we confirmed by histological that DM1-loaded ZNPs are nontoxic. Conclusion: DM1-loaded ZNPs have considerable antitumor activity. Thus, DM1-loaded ZNPs are a promising treatment of non-small cell lung cancer. [ABSTRACT FROM AUTHOR]

High magnitude impact loads caused by polygonal wear of the wheels have been associated with in-service failures of structural components of high-speed railways, although the mechanisms leading to wheels' polygonalisation is not yet fully understood. In this study, a long-term field test programme is undertaken and the data are analysed to gain better understanding of the growth in polygonal wear, and its characteristics and correlation with the axle box acceleration. The field measurements on a high-speed railway involved monitoring of wheels profiles between successive re-profiling of the wheels so as to identify the rate of growth of wear in addition to the axle box acceleration. The data suggested rapid growth in wheel wear, which could be characterised by polygonal wear of nearly 18th and 19th harmonic order. It is further shown that the magnitude of axle box acceleration increased considerably with increasing wear magnitude of the wheel. [ABSTRACT FROM AUTHOR]

Objective: We investigated syphilis prevalence among men who have sex with men (MSM) in China, as well as potential risk factors. Our principal hypothesis was that syphilis would be associated with the use of recreational drugs such as methamphetamines.Methods: From April to October 2013, we used several methods to recruit MSM in Qingdao, collecting demographic/behavioural information via self-administrated questionnaires. Trained health workers collected blood for the Treponema pallidum particle assay (TPPA) with positives confirmed by a toluidine red unheated serum test. We used an unmatched case-control study to identify factors that might predict syphilis infection using multivariable logistic regression.Results: We recruited 447 MSM who agreed to participate and who completed syphilis testing. Of 71 (15.9%) syphilis-positive MSM, 44 (62.0%) used drugs. Of 376 (84.1%) syphilis-negative MSM, 186 (49.5%) used drugs. We found a positive association with syphilis for any recreational drug use (crude OR (cOR) 1.7, 95 % CI 1.0 to 2.8), frequent methamphetamine use (cOR 2.4, 95% CI 1.1 to 5.3) and multiple drug use (adjusted OR (aOR) 3.4, 95% CI 1.3 to 9.2). Syphilis-positive men were more likely to have a higher physical depression score (aOR 5.2, 95% CI 1.1 to 24.4), be > 30 years old (aOR 2.7, 95% CI 1.5 to 4.8), report a prior STI (aOR 4.1, 95% CI 2.3 to 7.3) and report a sex party experience (aOR 2.2, 95% CI 1.1 to 4.4).Conclusions: Recreational drug use, depression and high-risk sexual behaviours were associated with syphilis infection among MSM in China. Only a multifaceted approach is likely be effective in control of both syphilis and HIV . [ABSTRACT FROM AUTHOR]