Abstract: To investigate the main occupational hazards of sand casting process enterprises, so as to provide insights into occupational disease prevention and control. Methods: In 2021 and 2022, six typical ferrous metal casting enterprises using sand casting technology in Wenling City, Zhejiang Province were selected to investigate the production processes and equipment, the operation of occupational disease prevention facilities and personal protective equipment. Occupational hazards including silica dust, noise, high temperature and ultraviolet radiation were detected and analyzed. Results: Six sand casting enterprises had not effectively set up and use occupational disease prevention equipment, and some employees had not worn personal protective equipment as required. The participation rate of occupational health examination was 100.00%. Among the 54 silica dust sampling points at the sand mixing, molding, sand falling, shot blasting and mud core drilling positions, the overall dust concentration exceeding the standard rate was 100.00%, and the respiratory dust exceeding the standard rate was 44.44%. Among the 55 noise measurement points at the sand mixing, sand falling, shot blasting, mud core drilling, polishing and blowing positions, 51 exceeded the standard, with a rate of 92.73%. Among the 90 sampling points for melting, painting, polishing, blowing and welding positions, the concentrations of welding fumes, manganese and its compounds, ethyl acetate and other cahmical factors did not exceed the standard. Six ultraviolet radiation measurement points in the welding position and six heat stress measurement points in the melting position did not exceed the standard. Conclusion The main occupational hazards of sand casting process enterprises in Wenling City are silica dust and noise, and occupational disease prevention and control should be further strengthened.

Objective To evaluate the effectiveness of a major depression animal model for old man es?tablished with orchidectomized(ORX) and subsequently olfactory bulbectomized(OBX) rat. Methods Healthy Sprague?Dawley male adult rats were randomly assigned to six groups with ten rats in each group:intact,sham?oper?ated,model,vehicle,fluoxetine plus testosterone propionate(Flu+TP) and amitriptyline plus testosterone propionate (Ami+TP) groups. ORX+OBX rat model was established. Therapy of Flu or Ami (10 mg/kg,i.p.) combined with TP(25 mg/kg,s.c.) was administered. Behavioral changes of rats in each group were detected. Results Open field test: The number of rat crossing lattices in model((124.50±14.25)lattices) or vehicle group( 118.70± 10.27) was significantly larger than those of intact(38.20±6.30),sham?operated(33.70±9.58),Flu+TP (34.00± 9.82) and Ami+TP group (35.20±12.54). The rearing number of model or vehicle group was also significantly larger than those of intact,sham?operated,Flu+TP and Ami+TP group.Statistical differences in the above corre?sponding comparisons of open field test existed (P<0.01). Forced swimming test: The immobility time of model ((131.70±32.44)s) or vehicle group ((135.10±34.01)s) was significantly longer than those of intact((66.60± 12.06)s),sham?operated((62.00±13.38)s),Flu+TP((59.60±8.89)s) and Ami+TP group ((64.80±10.78)s). There were statistical differences in the above corresponding comparisons (P<0.01). Morris water maze test: The escape latency of model((62.00±26.05)s) or vehicle group ((60.52±27.00)s) was significantly longer than those of intact((24.19±9.12)s),sham?operated((21.06±8.13)s),Flu+TP((22.88±8.01)s) and Ami+TP group ((27.04±10.11)s);while the time rat swimming in the quadrant originally put a platform of model or vehicle group was significantly shorter than those of intact,sham?operated,Flu+TP and Ami+TP group. There were statisti?cal differences in the above corresponding comparisons of Morris water maze test (P<0. 01, P<0. 05 ) . Conclusion The above data demonstrates that ORX+OBX rat model is both repeatability and reliability,and can be a major depression animal model of old man for future researches.