1Biomaterial inks for extrusion-based 3D bioprinting: Property, classification, modification, and selection.

Three-dimensional (3D) extrusion-based bioprinting is the most widely used bioprinting technology to fabricate bionic tissue or organ constructs by combining biomaterial ink and living cells for tissue engineering and regenerative medicine. One critical issue of this technique is the selection of suitable biomaterial ink to simulate extracellular matrix (ECM) that provides mechanical support for cells and regulates their physiological activities. Previous studies have demonstrated that it is an enormous challenge to form and maintain reproducible 3D constructs and eventually achieve the balance among biocompatibility, mechanical properties, and printability. This review highlights the properties of extrusion-based biomaterial inks and recent developments as well as details various biomaterial inks classified by their function. Key approaches related to their modification methods according to the functional requirements are also discussed, along with the selection strategies by varying extrusion paths and methods in extrusion-based bioprinting. This systematical review will assist researchers in identifying the most suitable extrusion-based biomaterial inks based on their requirements, as well as in elaborating current challenges and prospects of extrudable biomaterial inks in the field of bioprinting of in vitro tissue models.

Investigation of occupational hazard emergencies in power grid enterprises in three regions from 2018 to 2020 / 中国职业医学

Objective: To analyze the occurrence and risk factors of various occupational hazard incidents in China's power grid enterprises. Methods: A total of 4 191 workers from eight power grid enterprises in Jilin Province, Shandong Province, and Chongqing City were selected using a convenience sampling method. Their exposure in workplace and the occurrence of various occupational hazard incidents from 2018 to 2020 were investigated. Results: Among the participants, 71.7% were engaged in outdoor operations. The incidence rates of occupational hazard emergency, ranking from high to low, were electric ophthalmia, acute mountain sickness, heatstroke, electro-flash dermatitis, sunburn, cold injury, solar ophthalmia, and gas poisoning in confined space, with the rate of 42.3%, 42.3%, 38.1%, 24.3%, 17.4%, 16.5%, 10.0%, and 1.3%, respectively (P<0.01). The results of multivariate logistic regression analysis showed that workers in Jilin Province had a higher risk of cold injury compared to those in Shandong Province and Chongqing City (all P<0.01). Workers in Chongqing City had a higher risk of solar ophthalmia than those in Jilin Province (P<0.01). Workers in inspection and maintenance positions had a higher risk of heatstroke and sunburn compared to those in substation positions (all P<0.05). Power grid workers with protective systems in enterprises had a lower risk of sunburn and solar ophthalmia compared to those without protective systems (all P<0.01). The risks of sunburn and solar ophthalmia among power grid workers increased with age and daily outdoor working time (all P<0.05). Taking protective measures was a protective factor against heatstroke and cold injury (all P<0.01). Conclusion: Power grid workers face the risk of various occupational hazard incidents. Relevant organizations should conduct targeted preventive measures based on regional and worker characteristics, and ensure the implementation of protective systems in different work environments.

Advances in research and application of copy number variants in pediatric acute lymphoblastic leukemia：reports from the 57th American Society of Hematology annual meeting / 白血病·淋巴瘤

Recent studies showed that copy number variations in certain genes are closely correlated to progression and prognosis of pediatric acute lymphoblastic leukemia. Relevant reports in the 57th American Society of Hematology(ASH) annual meeting in 2015 will be reviewed together with research progress in recent years.