[ Objective ] The study aimed to discuss the optimal conditions for the treatment of enzymolysis wastewater by centrifugation - coagu- lation - Fenton reagent oxidation - adsorption process. [ Metbod] According to the...[ Objective ] The study aimed to discuss the optimal conditions for the treatment of enzymolysis wastewater by centrifugation - coagu- lation - Fenton reagent oxidation - adsorption process. [ Metbod] According to the water-quality characteristics of wastewater from a heparin so- dium production factory of Jiangsu Province, enzymolysis wastewater was segregated from intestinal lavage wastewater and treated through cen- trifugation- coagulation- Fenton reagent oxidation-adsorption process, and the optimal technical parameters were determined. E Resultl After enzymolysis wastewater was centrifuged at a speed of 4 000 rpm, 0.6 g/L CTS as the coagulant was added to the supematant. Hereafter, pH of the coagulated effluent was adjusted to 3, and then 1.5% （V/V） H2O2 was added to the coagulated effluent; a certain amount of ferrous sul- fate （n H2O2-.n FeSO4 . 7H2O =8：1 ） was added to the mixture; the reaction conducted for 30 min, and then solution pH was adjusted to about 9. Finally, the oxidized effluent flowed through a resin red until the adsorptive capacity reached 240 BV, and COD of the effluent water was lower than 100 mg/L, meeting the Grade-I standard of Comprehensive Discharge Standard of Sewage （GB8978-1996）. [Condusio] The research could provide a new process for the treatment of enzymolysis wastewater.展开更多
[ Objective] The study aimed to discuss the optimal conditions for the treatment of intestinal lavage wastewater by coagulation-ASBR- SBR process. [ Method] According to the water-quality characteristics of wastewater...[ Objective] The study aimed to discuss the optimal conditions for the treatment of intestinal lavage wastewater by coagulation-ASBR- SBR process. [ Method] According to the water-quality characteristics of wastewater from a heparin sodium production factory of Jiangsu Province, intestinal lavage wastewater was segregated from enzymolysis wastewater and treated using coagulation-ASBR-SBR process, and the effects of PFS dosage, HRT of ASBR and SBR reactor on the removal rate of COD and NH4＊ -N were analyzed. [ Result] The best dosage of PFS was 0.15 g/L, and the optimal HRT of ASBR reactor was 36 h, while the best HRT of SBR reactor was 15 h. Under the optimal conditions above, the removal rate of COD and NH,＊ -N reached 99.1% and 97.3% respectively, and the quality of the effluent water could reach the first standard of Comprehensive Discharge Standard of Sewage （GB8978-1996）. [ Conclusion ] The research could provide a new process for the treatment of intestinal lavage westewater.展开更多
2,4-dienoyl-CoA reductase 1 （ DECR1 ） is the key rate-limiting enzyme in the metabolism of polyunsaturated fatty acids. Although this protein has been studied in a variety of mammals, its role in por- cine is yet to...2,4-dienoyl-CoA reductase 1 （ DECR1 ） is the key rate-limiting enzyme in the metabolism of polyunsaturated fatty acids. Although this protein has been studied in a variety of mammals, its role in por- cine is yet to be fully elucidated. However, it is a candidate determinant/indicator of meat quality, growth traits, and carcass quality. Here, we employed RT-PCR and rapid amplification of cDNA ends （RACE） analysis to amplify the full-length cDNA of DECR1 from Mashen pig liver, and cloned it into the expression vector pET-32a＋. After confirmation by sequencing and restriction analysis, the recombinant plasmid was transformed into E. coli BL21 cells. The cDNA of pig DECR1 contained 2,352 nucleotides, including a 987 bp open reading frame flanked by a 53 bp 5＇-untranslated region （UTR） and a 1,312 bp 3＇-UTR. The pig DECR1 coding sequence encoded 328 amino acid residues, which shared 99%, 88%, 87%, 87%, 87%, 87%, and 83% identity with those of Sus scrofa （predicted）, Bos taurus, Homo sapiens, Macaca mulatta, Pan troglodytes, Equus caballus, Canis, and Mus musculus, respectively. SDS-PAGE analysis revealed that the recombinant protein was expressed and that the expression level reached its highest level after 4 h induction. Western blot analysis indicated that the molecular weight of the expressed protein was the same as that predicted, ap- proximately 35 kDa. Collectively these data provide the basis for further studies into the physiological functions and molecular mechanisms of the pig DE- CR1 gene.展开更多
Biological particles in the operating room(OR)air environment can cause surgical site infections(SSIs).Various ventilation systems have been employed in ORs to ensure an ultraclean environment.However,the effect of di...Biological particles in the operating room(OR)air environment can cause surgical site infections(SSIs).Various ventilation systems have been employed in ORs to ensure an ultraclean environment.However,the effect of different ventilation systems on the control of bacteria-carrying particles(BCPs)released from the surgical staff during surgery is unclear.In this study,the performance of four different ventilation systems(vertical laminar airflow ventilation(VLAF),horizontal laminar airflow ventilation(HLAP),differential vertical airflow ventilation(DVAF),and temperature-controlled airflow ventilation(TAF))used in an OR was evaluated and compared based on the spatial BCP concentration.The airflow field in the OR was solved by the Renormalization Group(RNG)k-e turbulence model,and the BCP phase was calculated by Lagrangian particle tracking(LPT)and the discrete random walk(DRW)model.It was found that the TAF system was the most effective ventilation system among the four ventilation systems for ensuring air cleanliness in the operating area.This study also indicated that air cleanliness in the operating area depended not only on the airflow rate of the ventilation system but also on the airflow distribution,which was greatly affected by obstacles such as surgical lamps and surgical staff.展开更多
This study analyzes the growth and reproduction of dust accumulated fungi(DAF)in an air-conditioning system based on field measurement and molecular biology,laboratory experiment and prediction modelling.The field mea...This study analyzes the growth and reproduction of dust accumulated fungi(DAF)in an air-conditioning system based on field measurement and molecular biology,laboratory experiment and prediction modelling.The field measurement was conducted to collect dust in filter screen,surface cooler and air supply duct of two air handling units(AHUs).The results indicate that dust volume and fungal number in two AHUs generally met the hygienic specification of public buildings,but the cleansing did not fulfil requirements.High-throughput sequencing was conducted,revealing that the dominant fungal species were Alternaria_betae-kenyensis,Cladosporium_delicatulum,Aspergillus_sydowii,Verticillium_dahliae.Laboratory experiment was conducted to analyze the impact of several factors(e.g.growth time,temperature,relative humidity,duct material)and their combination on the DAF growth.The results indicate that fungal growth increased with time,peaking at 4 days or 5 days.Higher relative humidity or temperature was conducive to fungal growth.The orthogonal experiment revealed that the condition of“antibacterial composite,22±1℃and 45%-55%RH”had the strongest inhibiting impact on fungal growth.Logistic model,Gompertz model and square-root model were further developed to predict the fungal growth under different conditions.The results show that the Logistic model had high feasibility and accuracy,the Gompertz model was feasible with lower accuracy and the square-root model was feasible with high accuracy.Overall,this study facilitates the understanding of the DAF growth in air-conditioning ducts,which is important for real-time prediction and timely control of the fungal contamination.展开更多
The outbreak of COVID-19 and the spread of infectious pathogens through bioaerosols have once again aroused widespread concern worldwide.Isolation ward is an important place to prevent the spread of infectious bioaero...The outbreak of COVID-19 and the spread of infectious pathogens through bioaerosols have once again aroused widespread concern worldwide.Isolation ward is an important place to prevent the spread of infectious bioaerosols.However,infection of health care workers(HCWs)in the isolation ward often occurs,so it is ur-gent to carry out relevant research to reduce the cross-infection between HCWs and patients.In this paper,the temporal and spatial distribution characteristics of bioaerosols under three mixed ventilation modes in a single ward were studied,namely,upper supply side return air of Case 1 and side supply and side return ventilation are Case 2 and Case 3 respectively.The results show that the removal efficiency of bioaerosol in the ventilation mode of Case 3,in which directional airflow is formed from the air supply inlet to the release source and then to the exhaust outlet,is 46.6%and 67.7%higher than that of Case 1 and Case 2,respectively.In addition,ventilation methods based on mixed theory do not guarantee good air quality in the breathing zone(1.3 m to 1.7 m)of HCWs,which may increase the inhalation risk for HCWs.It is hoped that our results can provide some useful suggestions for optimizing the airflow layout of the isolation ward,reducing the risk of cross-infection,and virus elimination.展开更多
In this paper,the progress and research related to aerosol containment by airflow in containment environments,e.g.,biosafety laboratories,are introduced from a mechanical engineering view.A good airdistribution strate...In this paper,the progress and research related to aerosol containment by airflow in containment environments,e.g.,biosafety laboratories,are introduced from a mechanical engineering view.A good airdistribution strategy in the room,a reasonable and stable pressure gradient in the containment area,and a necessary buffer room comprise the integral parts for regulating the air flow and providing the necessary containment.An optimal air-distribution strategy would reduce the residence time of the bioaerosol in the lab room and lower the exposure risk of the work staff.The pressure difference between adjacent rooms provides sufficient isolation protection when the door is closed.Nevertheless,an unfavorable air exchange would occur when the door is open,owing to door movement,passing people,or a tiny temperature difference.A buffer room is therefore necessary to offset the negative impact and maintain the containment effect.展开更多
Respiratory viruses can be attached to human exhaled particles and spread from person to person through respiratory activities.The purpose of this study is to obtain the quantitative description formula of human exhal...Respiratory viruses can be attached to human exhaled particles and spread from person to person through respiratory activities.The purpose of this study is to obtain the quantitative description formula of human exhaled particles in the ventilated room through amount number of numerical simulation calculations and regression statistical analysis of the simulated data.In this study,a combination of numerical simulation and laboratory experiments was used,and the results were tallied preferably.Bacillus subtilis was released as a release source to investigate the migration and distribution of bioaerosol.The results show that under the condition of high air supply velocity,due to the disturbance of human respiration and airflow,the diffusion velocity of exhaled particles was faster and the diffusion range is larger than that of low air supply velocity within the same time frame.No matter where the location of the manikin was in the room,the exhaled particles would spread to the whole room in at least 900 s.The method used in this study could be used to predict the distribution of human exhaled particles concentration in different indoor spaces,such as public transport and hospitals.These findings could provide valuable reference for the location of indoor air purifiers,which plays a guiding role in the construction of a healthy indoor environment.展开更多
In this study,standards of high-biocontainment facilities(including laboratories and large-scale production facilities)formulated by China and other countries were analyzed and compared,and the technical points and re...In this study,standards of high-biocontainment facilities(including laboratories and large-scale production facilities)formulated by China and other countries were analyzed and compared,and the technical points and requirements for Heating,Ventilating,and Air Conditioning(HVAC)systems in different series of standards were discussed.The main focus was on expounding the design and verification of the containment area’s indoor parameters,ventilation system,filter design,integrity test,fan standby,airflow pattern,and system reliability.This study expects suggestions and opinions on the construction and development of biosafety facilities in China and the possible future revision of relevant national standards.展开更多
基金Supported by the Project of Practical Innovation Training Program of Undergraduates in Jiangsu Province in 2012(232)Project of Visiting Engineers of Nanjing College of Chemical Technology in 2012
文摘[ Objective ] The study aimed to discuss the optimal conditions for the treatment of enzymolysis wastewater by centrifugation - coagu- lation - Fenton reagent oxidation - adsorption process. [ Metbod] According to the water-quality characteristics of wastewater from a heparin so- dium production factory of Jiangsu Province, enzymolysis wastewater was segregated from intestinal lavage wastewater and treated through cen- trifugation- coagulation- Fenton reagent oxidation-adsorption process, and the optimal technical parameters were determined. E Resultl After enzymolysis wastewater was centrifuged at a speed of 4 000 rpm, 0.6 g/L CTS as the coagulant was added to the supematant. Hereafter, pH of the coagulated effluent was adjusted to 3, and then 1.5% （V/V） H2O2 was added to the coagulated effluent; a certain amount of ferrous sul- fate （n H2O2-.n FeSO4 . 7H2O =8：1 ） was added to the mixture; the reaction conducted for 30 min, and then solution pH was adjusted to about 9. Finally, the oxidized effluent flowed through a resin red until the adsorptive capacity reached 240 BV, and COD of the effluent water was lower than 100 mg/L, meeting the Grade-I standard of Comprehensive Discharge Standard of Sewage （GB8978-1996）. [Condusio] The research could provide a new process for the treatment of enzymolysis wastewater.
基金Supported by the Project of Practical Innovation Training Program ofUndergraduates in Jiangsu Province in 2012(232)Project of VisitingEngineers of Nanjing College of Chemical Technology in 2012
文摘[ Objective] The study aimed to discuss the optimal conditions for the treatment of intestinal lavage wastewater by coagulation-ASBR- SBR process. [ Method] According to the water-quality characteristics of wastewater from a heparin sodium production factory of Jiangsu Province, intestinal lavage wastewater was segregated from enzymolysis wastewater and treated using coagulation-ASBR-SBR process, and the effects of PFS dosage, HRT of ASBR and SBR reactor on the removal rate of COD and NH4＊ -N were analyzed. [ Result] The best dosage of PFS was 0.15 g/L, and the optimal HRT of ASBR reactor was 36 h, while the best HRT of SBR reactor was 15 h. Under the optimal conditions above, the removal rate of COD and NH,＊ -N reached 99.1% and 97.3% respectively, and the quality of the effluent water could reach the first standard of Comprehensive Discharge Standard of Sewage （GB8978-1996）. [ Conclusion ] The research could provide a new process for the treatment of intestinal lavage westewater.
文摘2,4-dienoyl-CoA reductase 1 （ DECR1 ） is the key rate-limiting enzyme in the metabolism of polyunsaturated fatty acids. Although this protein has been studied in a variety of mammals, its role in por- cine is yet to be fully elucidated. However, it is a candidate determinant/indicator of meat quality, growth traits, and carcass quality. Here, we employed RT-PCR and rapid amplification of cDNA ends （RACE） analysis to amplify the full-length cDNA of DECR1 from Mashen pig liver, and cloned it into the expression vector pET-32a＋. After confirmation by sequencing and restriction analysis, the recombinant plasmid was transformed into E. coli BL21 cells. The cDNA of pig DECR1 contained 2,352 nucleotides, including a 987 bp open reading frame flanked by a 53 bp 5＇-untranslated region （UTR） and a 1,312 bp 3＇-UTR. The pig DECR1 coding sequence encoded 328 amino acid residues, which shared 99%, 88%, 87%, 87%, 87%, 87%, and 83% identity with those of Sus scrofa （predicted）, Bos taurus, Homo sapiens, Macaca mulatta, Pan troglodytes, Equus caballus, Canis, and Mus musculus, respectively. SDS-PAGE analysis revealed that the recombinant protein was expressed and that the expression level reached its highest level after 4 h induction. Western blot analysis indicated that the molecular weight of the expressed protein was the same as that predicted, ap- proximately 35 kDa. Collectively these data provide the basis for further studies into the physiological functions and molecular mechanisms of the pig DE- CR1 gene.
基金by the National Natural Science Foundation of China(Nos.41977368 and 51708211)the National Science and Technology Ministry of China(No.2017YFC0702800)+2 种基金the Opening Funds of State Key Laboratory of Building Safety and Built Environment National Engineering Research Center of Building Technology(No.BSBE2017-08)Natural Science Foundation of Hebei Province(No.E2017502051)the Fundamental Research Funds for the Central Universities(Nos.2018MS103 and 2020YJ007).
文摘Biological particles in the operating room(OR)air environment can cause surgical site infections(SSIs).Various ventilation systems have been employed in ORs to ensure an ultraclean environment.However,the effect of different ventilation systems on the control of bacteria-carrying particles(BCPs)released from the surgical staff during surgery is unclear.In this study,the performance of four different ventilation systems(vertical laminar airflow ventilation(VLAF),horizontal laminar airflow ventilation(HLAP),differential vertical airflow ventilation(DVAF),and temperature-controlled airflow ventilation(TAF))used in an OR was evaluated and compared based on the spatial BCP concentration.The airflow field in the OR was solved by the Renormalization Group(RNG)k-e turbulence model,and the BCP phase was calculated by Lagrangian particle tracking(LPT)and the discrete random walk(DRW)model.It was found that the TAF system was the most effective ventilation system among the four ventilation systems for ensuring air cleanliness in the operating area.This study also indicated that air cleanliness in the operating area depended not only on the airflow rate of the ventilation system but also on the airflow distribution,which was greatly affected by obstacles such as surgical lamps and surgical staff.
基金supported by the National Natural Science Foundation of China(No.51708211,No.41977368).
文摘This study analyzes the growth and reproduction of dust accumulated fungi(DAF)in an air-conditioning system based on field measurement and molecular biology,laboratory experiment and prediction modelling.The field measurement was conducted to collect dust in filter screen,surface cooler and air supply duct of two air handling units(AHUs).The results indicate that dust volume and fungal number in two AHUs generally met the hygienic specification of public buildings,but the cleansing did not fulfil requirements.High-throughput sequencing was conducted,revealing that the dominant fungal species were Alternaria_betae-kenyensis,Cladosporium_delicatulum,Aspergillus_sydowii,Verticillium_dahliae.Laboratory experiment was conducted to analyze the impact of several factors(e.g.growth time,temperature,relative humidity,duct material)and their combination on the DAF growth.The results indicate that fungal growth increased with time,peaking at 4 days or 5 days.Higher relative humidity or temperature was conducive to fungal growth.The orthogonal experiment revealed that the condition of“antibacterial composite,22±1℃and 45%-55%RH”had the strongest inhibiting impact on fungal growth.Logistic model,Gompertz model and square-root model were further developed to predict the fungal growth under different conditions.The results show that the Logistic model had high feasibility and accuracy,the Gompertz model was feasible with lower accuracy and the square-root model was feasible with high accuracy.Overall,this study facilitates the understanding of the DAF growth in air-conditioning ducts,which is important for real-time prediction and timely control of the fungal contamination.
基金This work was supported by the National Natural Science Foundation of China(Nos.42122058 and 41977368)the National Key R&D Program of China(2021YFF0604000)Natural Science Foundation of Hebei Province(No.E2021502046,and Fundamental Research Funds for the Central Universities(Nos.2021MS075 and 2020YJ007).
文摘The outbreak of COVID-19 and the spread of infectious pathogens through bioaerosols have once again aroused widespread concern worldwide.Isolation ward is an important place to prevent the spread of infectious bioaerosols.However,infection of health care workers(HCWs)in the isolation ward often occurs,so it is ur-gent to carry out relevant research to reduce the cross-infection between HCWs and patients.In this paper,the temporal and spatial distribution characteristics of bioaerosols under three mixed ventilation modes in a single ward were studied,namely,upper supply side return air of Case 1 and side supply and side return ventilation are Case 2 and Case 3 respectively.The results show that the removal efficiency of bioaerosol in the ventilation mode of Case 3,in which directional airflow is formed from the air supply inlet to the release source and then to the exhaust outlet,is 46.6%and 67.7%higher than that of Case 1 and Case 2,respectively.In addition,ventilation methods based on mixed theory do not guarantee good air quality in the breathing zone(1.3 m to 1.7 m)of HCWs,which may increase the inhalation risk for HCWs.It is hoped that our results can provide some useful suggestions for optimizing the airflow layout of the isolation ward,reducing the risk of cross-infection,and virus elimination.
基金This research is supported and financially funded by the National Key Research and Development Program of China(2016YFC1202201).
文摘In this paper,the progress and research related to aerosol containment by airflow in containment environments,e.g.,biosafety laboratories,are introduced from a mechanical engineering view.A good airdistribution strategy in the room,a reasonable and stable pressure gradient in the containment area,and a necessary buffer room comprise the integral parts for regulating the air flow and providing the necessary containment.An optimal air-distribution strategy would reduce the residence time of the bioaerosol in the lab room and lower the exposure risk of the work staff.The pressure difference between adjacent rooms provides sufficient isolation protection when the door is closed.Nevertheless,an unfavorable air exchange would occur when the door is open,owing to door movement,passing people,or a tiny temperature difference.A buffer room is therefore necessary to offset the negative impact and maintain the containment effect.
基金supported by the National Key R&D Program of China(No.2019YFC1520700)the National Natural Science Foundation of China(No.41977368)+1 种基金the National Science and Technology Ministry of China(No.2017YFC0702800)Opening Funds of State Key Laboratory of Building Safety and Built Environment National Engineering Research Center of Building Technology(No.BSBE2017-08).
文摘Respiratory viruses can be attached to human exhaled particles and spread from person to person through respiratory activities.The purpose of this study is to obtain the quantitative description formula of human exhaled particles in the ventilated room through amount number of numerical simulation calculations and regression statistical analysis of the simulated data.In this study,a combination of numerical simulation and laboratory experiments was used,and the results were tallied preferably.Bacillus subtilis was released as a release source to investigate the migration and distribution of bioaerosol.The results show that under the condition of high air supply velocity,due to the disturbance of human respiration and airflow,the diffusion velocity of exhaled particles was faster and the diffusion range is larger than that of low air supply velocity within the same time frame.No matter where the location of the manikin was in the room,the exhaled particles would spread to the whole room in at least 900 s.The method used in this study could be used to predict the distribution of human exhaled particles concentration in different indoor spaces,such as public transport and hospitals.These findings could provide valuable reference for the location of indoor air purifiers,which plays a guiding role in the construction of a healthy indoor environment.
文摘In this study,standards of high-biocontainment facilities(including laboratories and large-scale production facilities)formulated by China and other countries were analyzed and compared,and the technical points and requirements for Heating,Ventilating,and Air Conditioning(HVAC)systems in different series of standards were discussed.The main focus was on expounding the design and verification of the containment area’s indoor parameters,ventilation system,filter design,integrity test,fan standby,airflow pattern,and system reliability.This study expects suggestions and opinions on the construction and development of biosafety facilities in China and the possible future revision of relevant national standards.
