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Objective: To study the long-term morphological stability of three-dimensional (3D) printed photosensitive resin dental models under natural light and dark conditions. Methods: Eighty sets of resin dental models were made by the desktop 3D printer from one digital standard model set, and randomly divided into two groups, namely natural light group (40 sets) and dark group (40 sets). All resin models were stored in sealed bags, with 4 model sets from each group randomly collected after 1, 3, 5, 7, 14, 21, 28, 40, 60, or 90 days of storage and 3D scanned using an optical model scanner. The root-mean-square error (RMSE) was calculated to represent the mean deviation of the difference between the digital standard model and the scanned resin model. Meanwhile, three linear indexes (the width between the canines, the width between the first molars, and the arch length) of the resin dental model were measured and compared with the corresponding values of the standard model. RMSE and the linear measurements between the digital standard model and the scanned resin models were compared between the natural light group and the dark group and among models from different time points. Results: Compared with the digital standard model, the RMSE values of 96.9% (155/160) resin dental models were less than 0.1 mm within 90-day storage. Also, at the same time point, there was no significant difference in the RMSE between the natural light group and the dark group (P>0.05). 75.0% (360/480) of the absolute values of the linear differences (differences in inter-canine width, intra-molar width, and arch length between the digital standard model and the scanned resin model) were within 0.2 mm, and about 0.1% (3/480) of the linear differences were greater than 0.5 mm, and all of the linear differences were within 0.6 mm. Conclusions: 3D-printed resin dental models can be stored stably under natural light and dark conditions for a long time.
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ObjectiveTo investigate the effect of tumor-stroma crosstalk on amino acid metabolism in hepatic stellate cells (HSCs). MethodsHuman hepatoma cell lines HepG2, Hep3B, and Huh7 and the HSC LX-2 were cultured separately. HSCs were cultured in HSC LX-2 conditioned medium (LX2-CM) and HepG2/Hep3B/Huh7 mixed conditioned medium (Hep-CM), respectively. The supernatants were collected and an amino acid analyzer was used to measure the change in aminogram. The t-test was used for comparison of continuous data between groups. ResultsThere was a significant change in amino acid metabolism in HSCs. Compared with the LX2-CM control group, the Hep-CM experimental group had significant reductions in the levels of citrulline (t=3.426, P=0.027), valine (t=2.892, P=0.045), isoleucine (t=4.224, P=0.013), leucine (t=4.150, P=0.014), tyrosine (t=3556, P=0.024), phenylalanine (t=4.023, P=0.016), and lysine (t=3.369, P=0.028) in cell supernatant. ConclusionTumor-stroma crosstalk can influence amino acid metabolism in HSCs in tumor microenvironment, and such change in turn makes hepatoma cells better adapted to hypoxic microenvironment.
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Objective Under the guidance of graduate education evaluation theory,to establish the comprehensive quality evaluation standard of medical graduate students and apply it in the research of the scholarship evaluation.Methods Byusing literature study,brainstorming,expert advice and other research methods,we established comprehensive quality assessment scale.In the work of graduate scholarship,the scale was used to carry out the evaluation work,and the application of the scale,the use value and the effect of moral evaluation were studied.Results A comprehensive quality assessment scale for medical graduate students,which included 4 dimensions of moral education,training process,scientific research and social activities was established so that the students' daily performance was quantified and evaluated,which,to a certain extent,eliminated the influence of the subjective judgment to the evaluation work,and had good guidance and practicality.Conclusion Establishing comprehensive quality quantitative evaluation mechanism of the graduate students and conducting the dynamic evaluation to graduates' moral education,their academic and social activities are conducive to stimulating the development of postgraduates' comprehensive quality and improving the quality of training.
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Objective To establish a TLC identification method for Erhuang Capsule and to provide basis for the establishment of its quality standard.Methods TLC method was adopted.Results Nine kinds of medicinal materials such as Radix Rehmanniae,Radix Polygoni Multiflori,Rhizoma Gastrodiae had discriminating characteristics and distinctive spots.Conclusion TLC is a simple,reliable and specific method with good reproducibility,and can be used for the quality control of Erhuang Capsule.