A systematic investigation of the graphene oxide composite reduced by either p-phenylenediamine oligomers or hydrazine hydrate was performed with field emission scanning electron microscopy,high resolution transmissio...A systematic investigation of the graphene oxide composite reduced by either p-phenylenediamine oligomers or hydrazine hydrate was performed with field emission scanning electron microscopy,high resolution transmission electron microscopy,X-ray diffraction,fourier transform infrared,and X-ray photoelectron spectroscopy analyses.The electrical capacitance of the composite was evaluated by a cyclic voltammetry technique,while the properties of these prototype supercapacitors were measured by a chronopotentiometry technique.It was found that,under the solvothermal condition,the graphene oxide reduced by p-phenylenediamine oligomers was observed to have higher electrical capacitance than that reduced by hydrazine.The improved electrical capacitance can be attributed to that p-phenylenediamine oligomers are the more effective spacers for graphene layers;and they could also provide some pseudo-capacitance to the graphene oxide composite based on their conjugate structure.The results imply that graphene oxide modified by diamine oligomers has a good potential in energy storage devices.展开更多
A 1-D zigzag chain [Sn（edt）2（p-phenylenediamine）], （edt=ethane-l,2-thiolate） was synthesized by self-assembly and determined by X-ray structure analysis. The title compound （C10H16N2S4Sn） crystallizes in monoc...A 1-D zigzag chain [Sn（edt）2（p-phenylenediamine）], （edt=ethane-l,2-thiolate） was synthesized by self-assembly and determined by X-ray structure analysis. The title compound （C10H16N2S4Sn） crystallizes in monoclinic, space group C2/c with a=16.659（2）, b=7.0977（10）, c=12.4421（17） A°,β=96.577（2）°, V= 1461.5（4）A°^3, Z=4, Mr=411.18, Dc=1.869 g/cm^3, F（000）=816,μ=2.300 mm^-1, the final R=0.0332 and wR=0.0837 for 1142 observed reflections （I〉2σ（I））. In the complex, Sn^4＋ ion is six-coordinated with four sulfur atoms of two edt ligands from equatorial positions and two nitrogen atoms of p-phenylenediamine ligands from axial positions. The zigzag chain thus formed is parallel to the a axis.展开更多
The molar reation enthalpy,the Michaelis constant and the observed rate constant of the reaction between the Rhus vernicifera laccase and p-phenylenediamine have been determined at 298. 15 K by LKB-2107 microcalorimet...The molar reation enthalpy,the Michaelis constant and the observed rate constant of the reaction between the Rhus vernicifera laccase and p-phenylenediamine have been determined at 298. 15 K by LKB-2107 microcalorimetry system in 0.1 mol/L phosphate salt buffer (pH7. 4) to be △rHm=-136.36±0. 36kJ/mol, Km= 5. 58×10-3 mol/L and k1 =8. 63×10-3s-1, respectively. The catalyst activity of laccase withp-phenylenediamine as substrate has been determined to be EA=0. 045 IU in the experimental condition.The observed activation energy of non-enzymic step of the reaction, the Gibbs binding energy of the combination process of laccase and substrate have been also calculated. The physical significance of the determined parameters were discussed for different step of the reaction.展开更多
Hairdressers are chronically exposed to several occupational hazards during their work including potentially genotoxic chemicals. Hair dying, hair smoothening and straightening products are hazardous chemicals that af...Hairdressers are chronically exposed to several occupational hazards during their work including potentially genotoxic chemicals. Hair dying, hair smoothening and straightening products are hazardous chemicals that affect human health and are frequently used in beauty salons. So, this study aimed to evaluate the genotoxic risk among the studied hairdressers, to estimate the level of p-phenylenediamine (p-PDA) in urine and to assess the degree of adherence of the studied hair- dressers to occupational safety measures at work. A comparative cross sectional study was carried out on 40 hairdressers working in beauty salons in Zagazig city, Egypt and 40 administrative staff at faculty of medicine as a control group. The results of the study revealed a significant increase in mean concentration of urinary p-PDA as well as significant increase in DNA damage assessed by Comet assay in lymphocytes among studied hairdressers than among their controls. Also, there was a statistically significant decrease in adherence to most of the occupational safety precaution measures that should be followed by the studied hairdressers. The significant risk factors of high Comet total mean score among the studied hairdressers were occupational use of hair straightening ≥8 times/week, use of hair dyes at work ≥15 times/week, length of service ≥13 years, negligence of wearing gloves during work, use of bleaching agents ≥12/week and negligence of hand wash after handling chemicals. So, it was concluded that the hairdressers are occupationally exposed to the risk of genotoxic hazards from chemicals frequently used in their work. The lack of commitment to occupational safety measures at beauty salons like wearing gloves during work and hand washing increases the risk of genotoxicity.展开更多
According to Hygienic Standard for Cosmetics (2007 Edition) and Safety and Technical Standards for Cosmetics (2015 Edition), Oxidative Hair Dyes were supervised and inspected in Yangzhou from 2013 to 2018. P-Phenylene...According to Hygienic Standard for Cosmetics (2007 Edition) and Safety and Technical Standards for Cosmetics (2015 Edition), Oxidative Hair Dyes were supervised and inspected in Yangzhou from 2013 to 2018. P-Phenylenediamine and other 6 kinds of components from 85 batches of samples were determined and analyzed by HPLC. Only one batch of samples had not passed test, o-Phenylenediamine was detected that should be prohibited in hair dyes. The results of supervision and inspection for oxidative hair dyes were good in Yangzhou from 2013 to 2018.展开更多
基金the University Innovation Research and Training Program(C201603050,C201703648,and C201803850)of China University of Mining and Technology,Beijing2018 University Student Entrepreneurship Practice Project。
文摘A systematic investigation of the graphene oxide composite reduced by either p-phenylenediamine oligomers or hydrazine hydrate was performed with field emission scanning electron microscopy,high resolution transmission electron microscopy,X-ray diffraction,fourier transform infrared,and X-ray photoelectron spectroscopy analyses.The electrical capacitance of the composite was evaluated by a cyclic voltammetry technique,while the properties of these prototype supercapacitors were measured by a chronopotentiometry technique.It was found that,under the solvothermal condition,the graphene oxide reduced by p-phenylenediamine oligomers was observed to have higher electrical capacitance than that reduced by hydrazine.The improved electrical capacitance can be attributed to that p-phenylenediamine oligomers are the more effective spacers for graphene layers;and they could also provide some pseudo-capacitance to the graphene oxide composite based on their conjugate structure.The results imply that graphene oxide modified by diamine oligomers has a good potential in energy storage devices.
基金This research was supported by the State Key Laboratory of Structural Chemistry, the National Natural Science Foundation of China (20273073, 20333070, 90206040) and Natural Science Foundation of Fujian Province (2004J041, 2003J042, 2004HZ01-1)
文摘A 1-D zigzag chain [Sn（edt）2（p-phenylenediamine）], （edt=ethane-l,2-thiolate） was synthesized by self-assembly and determined by X-ray structure analysis. The title compound （C10H16N2S4Sn） crystallizes in monoclinic, space group C2/c with a=16.659（2）, b=7.0977（10）, c=12.4421（17） A°,β=96.577（2）°, V= 1461.5（4）A°^3, Z=4, Mr=411.18, Dc=1.869 g/cm^3, F（000）=816,μ=2.300 mm^-1, the final R=0.0332 and wR=0.0837 for 1142 observed reflections （I〉2σ（I））. In the complex, Sn^4＋ ion is six-coordinated with four sulfur atoms of two edt ligands from equatorial positions and two nitrogen atoms of p-phenylenediamine ligands from axial positions. The zigzag chain thus formed is parallel to the a axis.
文摘The molar reation enthalpy,the Michaelis constant and the observed rate constant of the reaction between the Rhus vernicifera laccase and p-phenylenediamine have been determined at 298. 15 K by LKB-2107 microcalorimetry system in 0.1 mol/L phosphate salt buffer (pH7. 4) to be △rHm=-136.36±0. 36kJ/mol, Km= 5. 58×10-3 mol/L and k1 =8. 63×10-3s-1, respectively. The catalyst activity of laccase withp-phenylenediamine as substrate has been determined to be EA=0. 045 IU in the experimental condition.The observed activation energy of non-enzymic step of the reaction, the Gibbs binding energy of the combination process of laccase and substrate have been also calculated. The physical significance of the determined parameters were discussed for different step of the reaction.
文摘Hairdressers are chronically exposed to several occupational hazards during their work including potentially genotoxic chemicals. Hair dying, hair smoothening and straightening products are hazardous chemicals that affect human health and are frequently used in beauty salons. So, this study aimed to evaluate the genotoxic risk among the studied hairdressers, to estimate the level of p-phenylenediamine (p-PDA) in urine and to assess the degree of adherence of the studied hair- dressers to occupational safety measures at work. A comparative cross sectional study was carried out on 40 hairdressers working in beauty salons in Zagazig city, Egypt and 40 administrative staff at faculty of medicine as a control group. The results of the study revealed a significant increase in mean concentration of urinary p-PDA as well as significant increase in DNA damage assessed by Comet assay in lymphocytes among studied hairdressers than among their controls. Also, there was a statistically significant decrease in adherence to most of the occupational safety precaution measures that should be followed by the studied hairdressers. The significant risk factors of high Comet total mean score among the studied hairdressers were occupational use of hair straightening ≥8 times/week, use of hair dyes at work ≥15 times/week, length of service ≥13 years, negligence of wearing gloves during work, use of bleaching agents ≥12/week and negligence of hand wash after handling chemicals. So, it was concluded that the hairdressers are occupationally exposed to the risk of genotoxic hazards from chemicals frequently used in their work. The lack of commitment to occupational safety measures at beauty salons like wearing gloves during work and hand washing increases the risk of genotoxicity.
文摘According to Hygienic Standard for Cosmetics (2007 Edition) and Safety and Technical Standards for Cosmetics (2015 Edition), Oxidative Hair Dyes were supervised and inspected in Yangzhou from 2013 to 2018. P-Phenylenediamine and other 6 kinds of components from 85 batches of samples were determined and analyzed by HPLC. Only one batch of samples had not passed test, o-Phenylenediamine was detected that should be prohibited in hair dyes. The results of supervision and inspection for oxidative hair dyes were good in Yangzhou from 2013 to 2018.
