1.Geometric Modeling of Prosthetic Socket
Xuejun CAO ; Xiansheng NI ; Wenyong LIU ; Junchen WANG ; Feng LI ; Tonglei LI
Chinese Journal of Rehabilitation Theory and Practice 2009;15(3):283-285
Objective To investigate the geometric modeling method for trans-femoral prosthetic socket. Methods The socket reference shapes (i.e. shape templates) were constructed based on the statistic analysis and integrated into the CASD program. The initial socket shape was obtained by transformation from the corresponding reference shape based on the data from the patient's stump and the final socket shape was determined by a kind of three-dimensional interaction method under the OpenGL environment. The fabrication experiment is conducted on the specialized numerical control machine. Results The interactive modification method was easy to use. The machined socket mold is consistent with the designed model in the shape and the precision. Conclusion This method can meet the clinical requirements in the main, but need to optimize the surface shaping characters and rules during the interactive modification stage.
2.Intracellular uptake of nanocrystals: Probing with aggregation-induced emission of fluorescence and kinetic modeling.
Jifen ZHANG ; Clairissa D CORPSTEIN ; Tonglei LI
Acta Pharmaceutica Sinica B 2021;11(4):1021-1029
Nanocrystal formulations have been explored to deliver poorly water-soluble drug molecules. Despite various studies of nanocrystal formulation and delivery, much more understanding needs to be gained into absorption mechanisms and kinetics of drug nanocrystals at various levels, ranging from cells to tissues and to the whole body. In this study, nanocrystals of tetrakis (4-hydroxyphenyl) ethylene (THPE) with an aggregation-induced emission (AIE) property was used as a model to explore intracellular absorption mechanism and dissolution kinetics of nanocrystals. Cellular uptake studies were conducted with KB cells and characterized by confocal microscopy, flow cytometry, and quantitative analyses. The results suggested that THPE nanocrystals could be taken up by KB cells directly, as well as in the form of dissolved molecules. The cellular uptake was found to be concentration- and time-dependent. In addition, the intracellular THPE also could be exocytosed from cells in forms of dissolved molecules and nanocrystals. Kinetic modeling was conducted to further understand the cellular mechanism of THPE nanocrystals based on first-order ordinary differential equations (ODEs). By fitting the kinetic model against experimental measurements, it was found that the initial nanocrystal concentration had a great influence on the dynamic process of dissolution, cellular uptake, and exocytosis of THPE nanocrystals. As the nanocrystal concentration increased in the culture media, dissolution of endocytosed nanocrystals became enhanced, subsequently driving the efflux of THPE molecules from cells.
3.Analysis of monitoring results of coal-burning-borne endemic fluorosis in Ankang City of Shaanxi Province from 2019 to 2023
Ying DENG ; Tonglei ZHANG ; Lei LIANG ; Feng SU ; Xiaoqian LI ; Zhongxue FAN ; Rong ZHOU
Chinese Journal of Endemiology 2024;43(10):813-817
Objective:To evaluate the prevention and control effect of coal-burning-borne endemic fluorosis in Ankang City of Shaanxi Province, so as to provide a scientific basis for formulating precise prevention and control strategies in the future.Methods:From 2019 to 2023, according to the requirements of the "Monitoring Program of Shaanxi Province for Coal-burning-borne Endemic Fluorosis (2019 Edition)", full coverage monitoring was carried out in all affected villages in seven affected counties under the jurisdiction of Ankang City. Using the simple random sampling method, 30 households in each affected village were selected to investigate the use of improved stoves and the formation of health-related behaviors. All children aged from 8 to 12 in the village were examined for the prevalence of dental fluorosis. At the same time, 6 monitoring villages were selected in 2019, and 8 monitoring villages were selected in 2023 to collect real-time urine samples from children aged 8 - 12 for determination of urinary fluoride level. The evaluation for control and elimination of disease areas was carried out in accordance with the "Evaluation Approach for Control and Elimination of Priority Endemic Diseases (2019 Edition)".Results:From 2019 to 2023, a total of 203 880 households were monitored, the rate of qualified improved stoves and the correct use rate of qualified improved stoves were more than 95.00%. The utilization rate of improved stoves decreased from 16.34% (6 584/40 290) in 2019 to 8.89% (3 706/41 700) in 2023, showing a decreasing trend year by year (χ 2trend = 3 400.37, P < 0.001). The utilization rate of clean energy increased from 82.52% (33 247/40 290) in 2019 to 94.36% (39 350/41 700) in 2023, showing an upward trend year by year (χ 2trend = 7 506.09, P < 0.001). The correct drying rate of corn and pepper for human consumption were 100.00%. A total of 455 327 children aged 8 - 12 were examined, and 2 301 cases of dental fluorosis were diagnosed, with a detection rate of 0.51%. Children with dental fluorosis were mainly extremely mild and mild, accounting for 94.87% (2 183/2 301). The dental fluorosis index was 0.012, indicating no trend of fluorosis prevalence. The detection rate of dental fluorosis in children decreased from 0.81% (765/94 537) in 2019 to 0.24% (204/86 066) in 2023, showing a declining trend year by year (χ 2trend = 375.45, P < 0.001). The geometric mean urinary fluoride levels of children aged 8 to 12 in 2019 and 2023 were 0.48 and 0.42 mg/L, respectively, with statistically significant differences between groups ( Z = - 3.05, P = 0.002). As of 2023, 1 390 affected villages had met the elimination criteria. Conclusions:The prevention and control of coal-burning-borne endemic fluorosis in Ankang City has achieved remarkable results, with all seven affected counties reaching the elimination standard. In the future, we should strengthen the management of high fluoride coal mines, continue to promote the use of clean energy, strengthen health promotion and disease monitoring, and continuously consolidate and improve the results of prevention and control.
4.Preparation and characterization of multimodal hybrid organic and inorganic nanocrystals of camptothecin and gold.
Christin P HOLLIS ; Alan K DOZIER ; Barbara L KNUTSON ; Tonglei LI
Acta Pharmaceutica Sinica B 2019;9(1):128-134
We demonstrate a novel inorganic-organic crystalline nanoconstruct, where gold atoms were imbedded in the crystal lattices as defects of camptothecin nanocrystals, suggesting its potential use as simultaneous agents for cancer therapy and bioimaging. The incorporation of gold, a potential computed tomography (CT) contrast agent, in the nanocrystals of camptothecin was detected by transmission electron microscope (TEM) and further quantified by energy dispersive X-ray spectrometry (EDS) and inductively coupled plasma-optical emission spectrometers (ICP-OES). Due to gold's high attenuation coefficient, only a relatively small amount needs to be present in order to create a good noise-to-contrast ratio in CT imaging. The imbedded gold atoms and clusters are expected to share the same biological fate as the camptothecin nanocrystals, reaching and accumulating in tumor site due to the enhanced permeation and retention (EPR) effect.
6.Development of carrier-free nanocrystals of poorly water-soluble drugs by exploring metastable zone of nucleation.
Xiaoting REN ; Jianping QI ; Wei WU ; Zongning YIN ; Tonglei LI ; Yi LU
Acta Pharmaceutica Sinica B 2019;9(1):118-127
There has been increasing interest in research and development of nanocrystals for the delivery of poorly water-soluble drugs that can be directly produced from solution. Compared with traditional carrier-based or encapsulation designs, drug nanocrystals circumvent possible side-effects due to carrier polymers and poor stability issues associated with encapsulation. The production of carrier-free nanocrystals requires careful control of nucleation and thus a thorough understanding of the relevant solution's metastable zone. A solution may stay supersaturated without forming any nuclei and become metastable. The maximal degree of supersaturation is known as the metastable zone width. When nucleation is triggered directly from the metastable zone, it helps to produce homogeneous nuclei leading to uniform nanocrystals. Herein, we report a study in which the solubility and metastable limit of paclitaxel (PTX) in ethanol aqueous solution were measured at 40 °C. A wide range of metastable compositions were studied to prepare carrier-free PTX nanocrystals with particle size smaller than 250 nm and PDI less than 0.25. Compared with the raw material, dissolution rate of PTX nanocrystals was significantly increased. The study enables production of high-quality drug nanocrystals for treating patients.