[Analysis of dust hazard characteristics in 59 ferrous metal foundry enterprises in Ningbo City]

Objective: To analyze the post distribution of dust concentration in ferrous metal foundry enterprises and evaluate the occupational health risks, and provide basis for policies of the formulation of pneumoconiosis prevention and control. Methods: From August to September in 2020, the basic information, dust hazard information and occupational health management information of 59 ferrous metal casting enterprises were investigated, the dust concentration distribution was analyzed, and the risk assessment was carried out by using the quantitative assignment model. The dust concentration is tested by LSD method after logarithmic treatment. The 3 times time weighted average allowable exposure concentration of dust is taken as the peak concentration limit of dust; The time weighted average allowable exposure concentration of dust converted by exposure time is taken as the time weighted average exposure concentration limit of dust, and whether the time weighted average exposure concentration and peak concentration of dust at the same post exceed the limit is taken as the basis for exceeding the limit of dust post concentration to calculate the post exceeding the limit rate. Results: The dust hazards were mainly distributed in the posts of sand treatment, molding, sand falling, sand cleaning and cutting and grinding. Dust exposure time weighted average concentration was 0.44 (0.03, 5.11) mg/m(3), peak exposure concentration was 1.30 (0.18, 10.94) mg/m(3), and the over standard rate of Posts was 38.92% (79/203) . Weighted average exposure concentration of other dust (total dust) in the cutting and grinding post is 1.50 (0.15, 7.40) mg/m(3), peak exposure concentration is 0.90 (0.07, 12.48) mg/m(3), and the post exceedance rate is 4.88% (2/41) . Weighted average exposure concentration of silica dust (exhaling dust) in dust operation posts of investment casting enterprises is 0.43 (0.05, 6.35) mg/m(3), peak exposure concentration is 0.90 (0.12, 8.28) mg/m(3), and the post over standard rate is 35.77% (49/137) ; Weighted average exposure concentration of other dust (total dust) at the cutting and grinding post is 2.00 (11.00, 21.00) mg/m(3), and the post exceedance rate is 2.50% (2/80) . There was no significant difference in the concentration of respirable dust between sand casting and investment casting (P>0.05) . The concentration of respirable dust in sand casting was higher than that in sand treatment, molding and sand cleaning posts (P<0.05) . The concentration of silica dust in investment casting was higher than that in sand treatment and molding posts, and that in sand cleaning posts was higher than that in sand treatment posts (P<0.05) . 98.48% (454/461) of the dust operation posts have an occupational health risk value greater than or equal to 400, and 1.52% (7/461) of the dust operation posts have an occupational health risk value of 200~399. Conclusion: there is a high rate of exceeding the standard in the dust work posts in the ferrous metal foundry enterprises in Ningbo, and the workers have a high occupational health risk of pneumoconiosis or metal and its compound pneumoconiosis. Targeted measures should be taken to reduce the occupational health risk.

[Effect and underling mechanism of 6% hydroxyethyl starch 130/0.4 on serum albumen in trauma orthopedic patients during operation]

Objective: To investigate the effect of 6% hydroxyethyl starch 130/0.4(HES) on protein in severe trauma orthopedic patients after acute hemodilution. Methods: Fourty-eight severe trauma patients who met the inclusion criteria were selected from June 2018 to December 2018 in Yantaishan Hospital, and were randomly divided into two groups (n=24): group A and group B. Group A was ringer's sodium lactate control group, and group B was HES treatment group. After the tracheal intubation, the patients of group A were infused with 10% blood volume of sodium lactate ringer at 0.5 ml·kg(-1)·min(-1), and the patients in group B were infused with 10% blood volume of HES at 0.5 ml·kg(-1)·min(-1). Total protein (TP), human serum albumin (HSA), numbers of circulating endothelium cells (CEC), C-reactive protein (CRP), and serum levels of tumor necrosis factor-alpha (TNF-α), interleukin (IL)-10 and IL-6 were measured immediately after acute hemodilution (T(0)), 24 hours (T(1)) and 48 hours (T(2)) after acute hemodilution. After infusion into human body, HES bond to HSA, and fluorescence spectroscopy was used to analyze the binding relationship between HES and HSA in order to further study the effects of HES on HSA. Results: The HSA, TP, CEC, TNF-α, IL-6, IL-10, CRP at T(0) of group A were (38±5) g/L, (66±5) g/L, (5.5±0.4)/0.9 μl, (24±5) μg/L, (8.9±0.8) μg/L, (44±6) μg/L, (13.6±1.4) mg/L; While at T(1) were (33±5) g/L, (60±6) g/L, (10.2±0.7)/0.9 μl, (87±9) μg/L, (38.8±2.3) μg/L, (57±7) μg/L, (23.4±2.4) mg/L. The HSA, TP, CEC, TNF-α, IL-6, IL-10, CRP at T(0) of group B were(38±4)g/L, (66±5) g/L, (5.4±0.6)/0.9 μl, (24±6) μg/L, (9.1±0.9) μg/L, (45±6) μg/L, (13.4±1.8) mg/L; While at T(1) were (35±5)g/L, (62±5)g/L, (7.4±0.6)/0.9 μl, (70±8) μg/L, (29.5±3.1) μg/L, (72±6) μg/L, (19.7±2.2) mg/L. HSA and TP decreased at T(1) in group A as compared with T(0) (P<0.05), contrarily CEC increased significantly at T(1), TNF-ɑ, IL-6, IL-10 and CRP augmented at T(1) and T(2) in two groups (P<0.05). In comparison with the patients of group A, CEC decreased significantly at T(1) (P<0.05). TNF-ɑ, IL-6, CRP reduced significantly at T(1) and T(2) (P<0.05), but IL-10 increased at T(1) and T(2) in group B (P<0.05). The secondary structure of HSA changed after HES was added in the HES solution. The fluorescence intensity of HSA decreased with the increase of HES concentration,which suggested that HES induced HSA fluorescence quenching. HES could bind to Trp-214 residue in HSA at a molecular ration of 1∶1. Conclusions: 6% HES reduces the occurrence of low protein level in severe trauma patients after operation. HES could bind to Trp-214 amino acid residue in HSA and form the complex at a molecular ratio of 1∶1. The formation of HES-HSA complex increases the volume of HES, avoids the vascular leakage, protects the vascular endothelial cells, and induces anti-inflammatory immunity in the patients with capillary syndrome.

Allocation of 14C-carbon in two species of larch seedlings infected with ectomycorrhizal fungi

The flow of labeled carbon in ectomycorrhizal and non-ectomycorrhizal seedlings of Japanese larch (Larix kaempferi Sarg.) and its F1 hybrid (Larix gmelinii Rupr. x L. kaempferi) was studied. Larch seedlings were grown in a greenhouse for 110 days with larch forest soil (FM) or Suillus grevillei (SM) inoculum, or in the absence of ectomycorrhizal fungi (NM). Shoots of colonized and NM seedlings were exposed to a pulse of 14CO2 for 1 h under natural light. Seedlings were harvested following 0, 6 and 24 h of exposure to 14CO2. At the final harvest, SM seedlings of Japanese larch and hybrid larch allocated 2.6 and 2.5% more 14C, respectively, to roots than NM seedlings. In contrast, FM seedlings of Japanese larch and hybrid larch allocated 6.5 and 18.0% more 14C, respectively, to the stem than NM seedlings. Of the total 14C detected in needle, stem and root fractions, FM and SM seedlings allocated a greater proportion than NM seedlings, perhaps because FM and SM seedlings had significantly (P < 0.05) higher photosynthetic rates than NM seedlings. As a result, FM and SM seedlings had greater dry masses than NM seedlings. Concentrations of nitrogen and phosphorus in FM and SM seedlings were significantly (P < 0.05) higher than in NM seedlings, as was stomatal conductance.