Objective To prepare two types of biodegradable modified materials (chitosan and collagen)and evaluate whether the new materials are suitable for tissue engineering cartilage.Methods Collagen and chitosan were both modified by poly-γ-benzyl-L-glutamate-co-glutamine acid (PBLG-co-PGA) with different proportions.The contact angle,degradation rate,tensile strength,cell attachment and cytocompatibility were tested and compared.Results As the PBLG-co-PGA content varied,the degradation rates of PBLG-co-PGA composites became adjustable,the hydrophilicity of PBLG-co-PGA/chitosan was improved,and the tensile strength increased in PBLG-co-PGA/collagen composite.The composites with 30％ PBLG-co-PGA were chosen for cytocompatibility and cell attachment experiments.The rabbit condrocytes grew significantly better on PBLG-co-PGA/chitosan than on other three materials(P＜0.05).Conclusion PBLG can improve the hydrophilicity,tensile strength and regulate the degradation rate of composite materials,and the cytocompatibility of the composites with 30％ of PBLG is good,among which PBLG-co-PGA/chitosan can even promote cell proliferation.It could be a new choice of scaffold for tissue engineering cartilage.

Objective: To study the current situation and distribution characteristics of pesticide poisoning in Ji'nan area, and to provide the basis for formulating the policy of scientific prevention and control of pesticide poisoning. Methods: The cases of pesticide poisoning from 2012 to 2016 were collected from medical institutions in Ji'nan, and the data was subjected to statistical analysis. Results: From 2012 to 2016 in Ji'nan reported a total of 2 237 cases of pesticide poisoning, non productive pesticide poisoning cases (72.78%, 2 149/2 237) and mortality (17.73%, 381/2 149) was significantly higher than that of productive pesticide poisoning. The average age is 46.78±18.57. The highest mortality rate of pesticide poisoning is more than 70 age group of the non productive pesticide poisoning. Organophosphorus pesticides (67.68%, 1 514/2 237) are the main pesticides causing poisoning, followed by herbicide (23.74%, 531/2 237). The highest mortality rate of pesticide was Paraquat (36.45%, 160/439), the second is the dichlorvos (19.19%, 170/886). Conclusion Pesticide poisoning is a public health problem and social problem which is harmful to the health of the residents in Ji'nan. It is necessary to strengthen the control and management of high toxic pesticides. Pay attention to the psychological intervention of elderly people to reduce the incidence of pesticide poisoning.