ABSTRACT
@#Objective To analyze the physical agent detection ability of occupational health technical service institutions in Methods Guangdong Province. A total of 92 institutions in Guangdong Province that participated in the inter laboratory comparison of physical agents organized in 2020 were taken as the research subjects using purposive sampling method. The ， Results certified physical factor items number of measuring instruments and measurement standards were investigated. The ， ， certification and accreditation project on physical agents in 92 institutions with certification and accreditation rate >80.0% ， ， ， - were noise high temperature ultraviolet radiation hand transmitted vibration and illumination. The certification approval rates ， ， ， ， of power frequency magnetic field 1 Hz to 100 kHz electric field 1 Hz to 100 kHz magnetic field laser radiation physical ， - < （ ） labor intensity and whole body vibration were 60.0%. The certification and accreditation rate of noise 98.9% was the ， （ ） （P< ） ， highest and that of the physical labor intensity 3.3% was the lowest 0.01 . As for the number of measuring instruments （ ） the number of noise measuring instruments accounted for the highest proportion 52.6% in 92 institutions. The number of ， （P< ） measuring instruments from the most to the least was grade A grade B and unqualified institutions 0.01 . The number of - （P< ） measuring instruments in private institutions was greater than that in non private institutions 0.01 . In the measurement ， ， standards some institutions that have certified power frequency electric field power frequency magnetic field and microclimate ， - projects still used the abandoned standard. Some institutions that have certified microclimate illuminance and whole body Conclusion ， vibration used the wrong measurement standards. Among the physical agents the certification and accreditation ， rate of noise is the highest and the number of noise related measuring instruments is the largest. The qualified institutions and private institutions have greater number of certification and accreditation projects on physical agents and measuring instruments.
ABSTRACT
@#Objective To assess the occupational health risk of noise in a plastic products enterprise and determine the key risk Methods - points. The workplace of a plastic products enterprise and its 388 noise exposed workers were selected as the ， research subjects using a convenient sampling method. The noise intensity in the workplace of the enterprise was measured and - GBZ/T 229.4-2012 the individual noise exposure level and pure tone hearing test were carried out in the noise exposed workers. Classification of Occupational Hazards at Workplaces--Part 4： Occupational Exposure to Noise（ GBZ/T hereinafter referred to as 229.4-2012） - was used to evaluate the hazardous degree of noise in different posts. The risk of high frequency hearing loss （ ） - （ ） - ， ， HFHL and occupational noise induced deafness ONID in noise exposed workers in different posts at 45.0 50.0 55.0 and WS/T 754-2016 Guideline for Risk Management of Occupational Noise Hazard（ 60.0 years of age were predicted using hereinafter WS/T 754-2016）Results referred to as . The noise in the workplace of this plastic product enterprise was found to exceed the - occupational exposure limits with the rate of 46.6%. The maximum level of normalization of equivalent continuous A weighted - （ ） sound pressure level to a nominal 40 h working week of exposure to noise in workers of six posts was 84.0 93.0 dB A . - ， ， ， According to GBZ/T 229.4 2012 the noise hazards of the posts including extrusion premixing unloading and utility - ， maintenance were mild or moderate except for the film and packaging posts. According to WS/T 754 2016 the risks of HFHL in ， ， the film and packaging operators at age ≥50.0 years old were at acceptable risk and the risks of HFHL in operators of extrusion ， ， premixing unloading and utility maintenance at age ≥45.0 years old were at moderate risk or high risk. The risks of ONID for ， the film packaging and utility maintenance operators at age ≥55.0 years old were at acceptable risk or moderate risk. The risksof ONID for extrusion premixing and unloading operators at age ≥50.0 years old were at high risk. Extrusion operators with （ ） exposure to toluene below the occupational exposure limit had a higher risk of HFHL high risk than unloading operators （ ） Conclusion moderate risk at age 45.0 years with the same noise intensity. The noise exposure intensity is high in the ， workplace of the plastic product enterprise. The workers in posts of extrusion premixing and unloading are at high risk levels of HFHL and ONID.
ABSTRACT
A green and sustainable nitrone formation reaction via visible-light-promoted reaction of aryl diazoacetates with nitrosoarenes is described. This protocol exhibits good functional group tolerance and broad substrate scope for both aryl diazoacetates with nitrosoarenes. Comparing the reported methods for the synthesis of nitrones from nitrosoarenes, the reaction described herein occurs under sole visible-light irradiation without the need of any catalysts and additives.
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The cortex root of Paeonia ostii, is used as a traditional Chinese medicine for treating female diseases. Phytochemical investigation of the water-soluble fraction of the plant led to the isolation of two new acetoisovanillone glycosides: acetoisovanillone-3-O-ß-D-glucopyranoside (1) and 2-hydroxy-acetoisovanillone-3-O-ß-D-glucopyranoside (2). Their structures were elucidated by extensive spectroscopic methods.
Subject(s)
Glycosides/chemistry , Paeonia , Female , Glycosides/isolation & purification , Humans , Medicine, Chinese Traditional , WaterABSTRACT
Developing high-performance electrocatalysts for urea oxidation reaction (UOR) can not only solve the problem of environmental pollution, but also solve the problem of the energy crisis by producing hydrogen for electrodes. The preparation of porous three-dimensional nanostructures as efficient electrocatalysts has become important work. Here, we developed a novel three-dimensional (3D) nanostructure of NiFe(OH) X nanoparticles/nickel foam with a high active area by a simple electroplating method and a subsequent treatment with ferric ion solution. This structure shows much greater UOR activity than the control sample (Ni/Ni foam) with the potential of 1.395 V (vs. RHE) (with an overpotential of 1.025 V) for driving the current density of 100 mA cm-2 in 1.0 M KOH electrolyte with 0.33 M urea. This work not only provides rapid and large-scale preparation of a three-dimensional nanostructure, but also gives a new way to design and obtain high-performance electrocatalysts.
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A solid amino-supported palladium catalyst is used in an oxidative domino reaction for the diastereoselective construction of alkyne-substituted cyclopentenol compounds. This heterogeneous catalyst exhibits high efficiency and excellent chemoselectivity, as well as good recyclability. The chemoselectivity of the domino reactions was readily controlled by switching the solvent and catalyst. Asymmetric syntheses and an oxidative carbocyclization-borylation reaction have also been developed based on the heterogeneous palladium catalyst.
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An efficient, photoredox-catalyst-free radical alkylation of quinoxalin-2(1H)-ones has been described. This reaction utilizes 4-alkyl-1,4-dihydropyridines (R-DHPs) as alkyl radical precursors and acetoxybenziodoxole (BI-OAc) as an electron acceptor to undergo single-electron transfer with photoexcited R-DHPs. The benign conditions allow for good compatibility in the scope of both quinoxalin-2(1H)-ones and R-DHPs. The synthetic value of the protocol was also demonstrated by the successful functionalization of natural products and drug-based complex molecules.
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A formal [3 + 2]-cycloaddition reaction of 2 H-azirines with nitrosoarenes has been achieved under irradiation by visible light with the assistance of organic dye photoredox catalyst. This method utilizes nitrosoarenes as efficient radical acceptors and provides a green and powerful method for a series of biologically important 1,2,4-oxadiazole derivatives in moderate to good yields.
ABSTRACT
A cascade radical addition/cyclization reaction of 2-vinylanilines with alkynes for the synthesis of biologically important naphthalene derivatives is reported. In this transformation, the in-situ-formed diazonium salts from 2-vinylanilines served as efficient aryl radical precursors and the reaction was run under metal-free conditions.
