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Computer simulation models have seldom been applied for estimating the structural and biophysical variables of forest canopy. In this study, an approach for the estimation of leaf area index (LAI) using the information contained in hyperspectral, multi-angle images and the inversion of a computer simulation model are explored. For this purpose, L-systems combined with forest growth model ZELIG were applied to render 3-D forest architectural scenarios. The Radiosity-graphics combined model (RGM) was used to estimate forest LAI from the Compact High-Resolution Imaging Spectrometer/Project for On-Board Autonomy (CHRIS/PROBA) data. LAI inversion was performed using the look-up table (LUT) method. The estimated LAI was evaluated against in situ LAI measurement and compared against the LAI predictions from CHRIS data obtained using the Li-Strahler geometric-optical canopy reflectance model (GOMS). The results indicated that the method used in this study can be efficient strategy to estimate LAI by RGM model inversion. [ABSTRACT FROM AUTHOR]

Objectives: A cross sectional study was performed to find the concentrations of elements contained in the semen of workers exposed to trinitrotoluene (TNT).Subjects and Methods: Semen of exposed workers in two TNT plants located in He-Nan Province in 1992 were examined.Results: The average TNT concentrations in the workplace, except the packing site, were found to have exceeded the maximal allowable concentration (MAC, 1 mg/m3); skin contaminations of male workers exposed to TNT were higher after a shift than in controls, and correlated with the total blood concentrations of TNT, 4-amino-2, 6-dinitrotoluene (4A), and 2-amino-4, 6-dinitrotoluene (2A). Cu, Zn, Na, Mg, and Se concentrations were significantly decreased, but K, Ca, Co, Mn and Li contents were not significantly changed in the semen of workers exposed to TNT. Compared with the control group, the percentage of liquifying time of semen, the sperm malformation incidence, and viability in the men exposed to TNT were all significantly changed.Conclusions: Men exposed to TNT have decreased concentrations of some elements is semen and altered semen physiology. [ABSTRACT FROM AUTHOR]

Objective: To establish a inductively coupled plasma mass spectrometry method for the determination of trace cobalt and tungsten in human urine. Methods: The authors used 1% nitric acid solution as diluent in October-December 2021, the sample dilution factor and internal standard element were optimized by single factor rotation experiment, and the difference between the working curve and the standard curve was compared. Results: The method uses working curve to determine cobalt and tungsten in urine, the linear range of this method was 0.0~10.0 μg/L, the correlation coefficient was 0.999 9, the detection limits respectively were 0.005 μg/L (cobalt) and 0.09 μg/L (tungsten), the recoveries of samples respectively were 87.0%~100.2% (cobalt) and 89.4%~104.8% (tungsten), the relative standard deviations respectively were 0.4%~4.4% (cobalt) and 0.6%~3.8% (tungsten) . Conclusion: A simple and rapid method for determination of cobalt and tungsten in urine has been established. This method has the advantages of simple operation, high sensitivity, low detection limit and good stability. It is suitable for determination of cobalt and tungsten in urine of all kinds of people.

Objective: To select and optimize the conditions of urine cobalt determination by graphite furnace atomic absorption spectroscopy and establish a method for urine cobalt determination. Methods: In April 2020, the matrix modifier and spectrum wavelength were selected by mathematical statistics method, the heating procedure of graphite furnace was optimized, the variance of orthogonal test results was analyzed, and the working curve was quantified by external standard method. Results: The results showed that the diammonium hydrogen phosphate was a matrix modifier with a wavelength of 240.7 nm, and the optimized graphite furnace heating procedure showed a good linear relationship at 5-80 μg/L. The correlation coefficient was 0.9991. The detection limit was 0.9 μg/L, the lowest detection concentration was 1.8 μg/L. The recovery was 94.0%-101.4%, and the precision was 2.6%-5.8%. Conclusion: The orthogonal design method can efficiently and scientifically optimize the optimal combination of the various factor levels of graphite furnace atomic absorption spectrometry. The determination method established based on this has high precision and good accuracy, and can be applied to the determination of cobalt in urine.

Objective: To find the risk assessment model of [di (2-ethylhexyl) phthalate, DEHP] fitting well for producing companies. Methods: The Cluster Sampling method was used in selecting a DEHP producing company in the occupational health and workplace environment monitoring study conducted between July and August in 2017. Data was collected by site evaluating and workplace environment monitoring. According to GBZ/T 298-2017《Technical Guidelines for Occupational Health Risk Assessment of Chemical Hazards in the Workplace》, a qualitative assessment method and a semi-quantitative comprehensive index method were chosen as the models and were compared. Results: The occupational health risk of the two methods rated 4 (high risk) and 2 (negligible risk) . Conclusion: The semi-quantitative comprehensive index method is more comprehensive and accurate when used to assess the occupational health risk caused by DEHP.

Objective: Improvement the method of nitrogen oxide sampling, analysis and detection in workplace air. Methods: Absorption and collection with sodium carbonate-sodium bicarbonate buffer solution, analysised by ion chromatography, anion column AS23, column temperature 30 ℃. Results: The linearity of the nitrite ion in the corresponding mass concentration range 0~90.0 μg/ml was good (Nitrogen dioxide in 0~120.0 mg/m(3)) , correlation coefficient>0.999 5. The detection limit was 0.16 μg/ml, The minimum detection concentration was 0.11 mg/m(3) with the sampling volume 7.5 L. Conclusion: The method has good accuracy, high sensitivity, with directing injection and no pre-treatment, and can popularize in general laboratories, and can satisfy the determination of nitrogen oxides in the air of workplace.

Objective: To assess psychological acceptance and occupational stress of medical staff, analyze the relationship among personality, psychological acceptance and occupational stress and discuss the direct or indirect effects of personality to occupational stress. Methods: The gaseous four kinds of carboxylic acids in the workplace air were simultaneously collected by silica gel tube, and then desorbed by deionized water and eluted by ion chromatograph. The the content was detected by conductivity detector. Results: The linear relationship was good in the concentration range of about 0~140 mg/L. The correlation coefficient r>0.999, and the maximum detection limit was 4.5 μg/mL. The sampling efficiency of the four carboxylic acids ranges from 96.10%~100.27%. Through the sample added recovery experiments, the low and high content of the silicone tube samples were detected; and the range of desorption efficiency was 82.18%~100.12%; the range of precision was 0.70%~3.71%. Conclusion: This method adopts deionized water to desorb samples, and the application of ion chromatography detection have reached the requirements of《Guidelines for the establishment of occupational health standards, Part 4: Determination of chemical substances in workplace air》, which can be used in four kinds of workplace air detection of carboxylic acid compounds.

Objective: To establish an HPLC method for determining p-Anisidine in workplace air. Methods: An C(18) capillary column was used with the detection wavelength of 240 nm, the methanol solution (v/v=62:38) as mobile phase, the flow rate was 0.9 ml/min, and the injection volume was 20 μl. Results: The linear range (μg/ml) for p-Anisidine was 0~100; correlation coefficient was 0.999 7; the detection limit was 0.15 μg/ml; the average precision of RSD was 4.4%. The sampling efficiency was more than 95% using silicone tube as sampling filter. Sample can be stored at room temperature for more than 7 d. Conclusion: the method appered to be accurate, simple, sensitive and reliable, also have a high sampling efficiency, and can be usd to determine p-anisidine in workplace air simultaneously.

Objective: To observe the effect of low dose naloxone combinewith ropivacaine for supraclavicular brachial plexus block. Methods: Seventy patients undergoing elective upper limb surgery were randomly divided into two groups, ropivacaine group (Group R, n =35) and naloxone group (Group N, n =35). An ultrasound guided technique was used in both two groups.The onset and duration time of sensory and motor blockade, visual analog score(VAS)of 3, 6, 12, 18, 24 h postoperatively, time of first request fordezocine, total amount of dezocine needed, incidence of nausea and vomiting postoperatively(PONV) and patients' satisfaction score for analgesia in 24 h after surgery were measured.At the same time, blood samples were taken before anesthesia, 6 h, 24 h after operation for inspecting the concentration of β-endorphin(β-EP)in plasma. Results: The duration of sensory and motor blockade, time of first request for dezocine in Group N were 736.0(713.5, 836.5), 514.5(491.3, 572.8), 708.5(683.2, 877.0)min, which were all prolonged compared to Group R(522.0(469.5, 606.5), 401.0(370.0, 458.5), 570.0(435.0, 618.5)min)( Z =-6.844, -6.758, -6.700, all P <0.01). The 6, 12, 18 h postoperatively VAS of Group N were 0, 5.0(3.0, 5.8), 5.0(5.0, 6.0)point. Among which the 6, 12 h postoperatively VAS of Group N were lower than that of Group R(1.0(1.0, 3.5), 6.0(6.0, 7.0)point)( Z =-6.596, -4.864, all P <0.01), while the 18 h postoperatively VAS was higher than that of Group R (5.0(4.0, 5.0)point)( Z =-2.603, P <0.01). Total amount of dezocine needed in Group N in 24 h after surgery was 7.5(5.0, 10.0)mg, which was lower than that of Group R(10.0(10.0, 15.0)mg)( Z =-3.449, P <0.01). The incidence of PONV after surgery in Group N was 21.9%, which was lower than that of Group R(45.5%)(χ(2)=4.034, P <0.05). Ptients' satisfaction score for analgesia in 24 h after surgery in Group N was 8.0(7.0, 8.0)point, which was higher than that of Group R(7.0(6.0, 7.0)point)( Z =-3.509, P <0.01). At 6 h postoperatively , the concentration of plasma β-EP in Group N was(113.34±12.36)μg/L, lower than that of Group R((147.14±11.65)μg/L)( t =-7.694, P <0.01). Conclusion: Low dose naloxone combine with ropivacaine for supraclavicular brachial plexus block, prolong the duration of sensory and motor blockade without affecting the onset time.

Objective: To establish a method for the determination of 1-hydroxy-2-butanone in urine by gas chromatography. Methods: Urine samples were acidified with hydrochloric acid, and then stored in the refrigerator . After thawing under natural conditions, urine volume of 2.0 ml was extracted by C 18 solid phase, using methanol volume of 2.0 ml elution, detected by gas chromatography with FID detector and quantified by external standard method. Results: The measurement range of method is 0.986 ~32.88 μg/ml, correlation coefficient ( r ) =0.999 7, detection limit is 0.13 μg/ml; The recovery is 88.1% ~92.2% ; The precision is 1.4% ~3.2%. Conclusion: This method has a high sensitivity and simple processing. All technical indicators can meet the requirements of the determination method.