Considering the variations in imaging sizes of the unmanned aerial vehicles(UAV)at different aerial photography heights,as well as the influence of factors such as light and weather,which can result in missed detectio...Considering the variations in imaging sizes of the unmanned aerial vehicles(UAV)at different aerial photography heights,as well as the influence of factors such as light and weather,which can result in missed detection and false detection of the model,this paper presents a comprehensive detection model based on the improved lightweight You Only Look Once version 8s(YOLOv8s)algorithm used in natural light and infrared scenes(L_YOLO).The algorithm proposes a special feature pyramid network(SFPN)structure and substitutes most of the neck feature extraction module with the Special deformable convolution feature extraction module(SDCN).Moreover,the model undergoes pruning to eliminate redundant channels.Finally,the non-maximum suppression algorithm of intersection-union ratio based on minimum point distance(MPDIOU_NMS)algorithm has been integrated to eliminate redundant detection boxes,and a comprehensive validation has been conducted using the infrared aerial dataset and the Visdrone2019 dataset.The comprehensive experimental results demonstrate that when the number of parameters and floating-point operations is reduced by 30%and 20%,respectively,there is a 1.2%increase in mean average precision at a threshold of 0.5(mAP(0.5))and a 4.8%increase in mAP(0.5:0.95)on the infrared dataset.Finally,the mAP on the Visdrone2019 dataset has experienced an average increase of 12.4%.The accuracy and recall rates have seen respective increases of 9.2%and 3.6%.展开更多
This study aims to realize the sharing of near-infrared analysis models of lignin and holocellulose content in pulp wood on two different batches of spectrometers and proposes a combined algorithm of SPA-DS,MCUVE-DS a...This study aims to realize the sharing of near-infrared analysis models of lignin and holocellulose content in pulp wood on two different batches of spectrometers and proposes a combined algorithm of SPA-DS,MCUVE-DS and SiPLS-DS.The Successive Projection Algorithm(SPA),the Monte-Carlo of Uninformative Variable Elimination(MCUVE)and the Synergy Interval Partial Least Squares(SiPLS)algorithms are respectively used to reduce the adverse effects of redundant information in the transmission process of the full spectrum DS algorithm model.These three algorithms can improve model transfer accuracy and efficiency and reduce the manpower and material consumption required for modeling.These results show that the modeling effects of the characteristic wavelengths screened by the SPA,MCUVE and SiPLS algorithms are all greatly improved compared with the full-spectrum modeling,in which the SPA-PLS result in the best prediction with RPDs above 6.5 for both components.The three wavelength selection methods combined with the DS algorithm are used to transfer the models of the two instruments.Among them,the MCUVE combined with the DS algorithm has the best transfer effect.After the model transfer,the RMSEP of lignin is 0.701,and the RMSEP of holocellulose is 0.839,which was improved significantly than the full-spectrum model transfer of 0.759 and 0.918.展开更多
目的:探讨经脐单孔+1孔腹腔镜(single-incision plus one-port laparoscopic surgery,SILS+1)结直肠癌根治术的安全性及可行性。方法:回顾性分析2017年10月至2019年11月赣南医学院第一附属医院收治的8例进行经脐SILS+1结直肠癌根治术患...目的:探讨经脐单孔+1孔腹腔镜(single-incision plus one-port laparoscopic surgery,SILS+1)结直肠癌根治术的安全性及可行性。方法:回顾性分析2017年10月至2019年11月赣南医学院第一附属医院收治的8例进行经脐SILS+1结直肠癌根治术患者的临床资料。结果:8例结直肠癌患者手术均顺利完成,无中转开腹及增加戳卡孔数量,手术平均时间107(95~124)min,平均出血33(10~80)mL,2例患者出现术后发热,考虑术后吸收热可能,术后第3天自行退热,其余患者术后无明显外科并发症,术后1~3天胃肠道功能恢复,3~5天拔出腹腔引流管,术后住院时间约9.3(7~11)天。术后病理再次证实为结直肠腺癌,淋巴结检出平均数目为13.6(11~16)枚,均无围手术期严重并发症及死亡的发生。术后随访3~24个月,平均10个月,未发现肿瘤局部复发、腹壁戳孔切口种植转移。结论:经脐SILS+1结直肠癌根治术安全可行,创伤小,美容效果令人满意,但远期疗效有待进一步观察。展开更多
Host-less lithium metal anode generally suffers from large volume changes and serious dendrite growth during cycling,which poses challenges for its practical application.Interpenetrating phase composites with continuo...Host-less lithium metal anode generally suffers from large volume changes and serious dendrite growth during cycling,which poses challenges for its practical application.Interpenetrating phase composites with continuous architectures offer a solution to enhance mechanical properties of materials.Herein,a robust composite Li anode(LBN)material is fabricated through the metallurgical reaction between Li and hexagonal boron nitride(h-BN)with the formation of interpenetrating LiB/Li_(3)BN_(2)phases.As LiB fibers are anchored by Li_(3)BN_(2)granules,the collapse and slippage of LiB fibers are suppressed whilst the mechanical strength and structural stability of LBN are reinforced.By rolling,ultrathin(15μm),freestanding,and electrochemically stable LBN foil can be obtained.The LBN anode exhibits a high average Coulombic efficiency of 99.69%(1 mA cm^(-2),3 mAh cm^(-2))and a long lifespan of 2500 h(1 mA cm^(-2),1 m Ah cm^(-2)).Notably,the LiCoO_(2)(with double-sided load 40 mg cm^(-2))|LBN pouch cell can operate over450 cycles with a capacity retention of 90.1%.The exceptional cycling stability of LBN can be ascribed to the interpenetrating reinforcement architectures and synergistic electronic/ionic conductivity of the LiB/Li_(3)BN_(2)dual-lithiophilic-phases.This work provides a new methodology for thin Li strip processing and reinforced-architecture design,with implications beyond battery applications.展开更多
Dear Editor,Sorghum(Sorghum bicolor[L.]Moench)(2n=20),a C4 droughttolerant cereal crop,is widely cultivated for food,feed,and biofuel,resulting in varieties with distinct morphological characteristics.The Sanger-seque...Dear Editor,Sorghum(Sorghum bicolor[L.]Moench)(2n=20),a C4 droughttolerant cereal crop,is widely cultivated for food,feed,and biofuel,resulting in varieties with distinct morphological characteristics.The Sanger-sequencing-based sorghum reference genome of the inbred variety BTx623(grain sorghum)was initially released in 2009(base error<1 per 10 kb)(Paterson et al.,2009),and the most widely used version 3 assembly(base error<1 per 100 kb),consisting of 4773 contigs with 2679 unresolved gaps(~28 Mb)in 10 chromosomes,was improved by next-generation sequencing in 2017(McCormick et al.,2018).展开更多
Infectious disease departments in hospitals require pressure gradient to create unidirectional airflow to prevent the spread of contaminants,typically by creating active air infiltration through the difference between...Infectious disease departments in hospitals require pressure gradient to create unidirectional airflow to prevent the spread of contaminants,typically by creating active air infiltration through the difference between supply and exhaust air volumes.The door gap is the channel of air flow between rooms,so its height has an important influence on the pressure difference and infiltration air volume of the room.There is still a lack of research on setting reasonable ventilation strategies according to the different heights of door gaps at different positions in the building.In this study,model of a set of isolation wards was established and analyzed using the multi-zone simulation software CONTAM,and the ventilation strategies with different heights of door gaps were applied to the actual infection diseases department.The results show that in a building with ventilation system divided by functional area,the difference in the height of the door gaps requires different active infiltration air volumes.Pressure fluctuations in the medical and patient corridors are greater than in other rooms.The significance of this study is to understand the active infiltration of air to guide the design and operation of ventilation systems in infectious disease hospitals or building remodeled to isolate close contacts of COVID-19 patients.It is also instructive for the design of pressure gradients in clean workshops,biological laboratories,and other similar buildings.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
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
A few-mode fiber (FMF) is designed to support three spatial modes (LP01, LP 11a, and LP 11 b) and fabricated through plasma chemical vapor deposition (PCVD)and rod-in-tube (RIT) method. Using PDM-DFTS-OFDM- 32...A few-mode fiber (FMF) is designed to support three spatial modes (LP01, LP 11a, and LP 11 b) and fabricated through plasma chemical vapor deposition (PCVD)and rod-in-tube (RIT) method. Using PDM-DFTS-OFDM- 32QAM modulation, wavelength division multiplexing, mode multiplexing, and coherent detection, we successfully demonstrated 200Tb/s (375× 3 × 178.125Gb/s) signal over 1 km FMF using C and L bands with 25 GHz channel spacing. After 1 km FMF transmission, all the tested bit error rates (BERs) are below 20% forward error correction (FEC) threshold (2.0 × 10-2). Within each sub-channel, we achieved a spectral efficiency of 21.375 bits/Hz in the C and L bands.展开更多
Snail, a family of zinc finger transcription factors, plays an important role in morphogenesis and embryogenesis. Snail zinc finger family 2 (SNAI2 or Slug) has been demonstrated to regulate carcinogenesis of severa...Snail, a family of zinc finger transcription factors, plays an important role in morphogenesis and embryogenesis. Snail zinc finger family 2 (SNAI2 or Slug) has been demonstrated to regulate carcinogenesis of several human cancers including breast, prostate, head, neck,展开更多
To assess associations between home indoor air environments and asthma,allergies and pneumonia,children aged 1–8 years were surveyed from 12 kindergartens in the city of Xi’an.2,020 questionnaires were responded wit...To assess associations between home indoor air environments and asthma,allergies and pneumonia,children aged 1–8 years were surveyed from 12 kindergartens in the city of Xi’an.2,020 questionnaires were responded with a response rate of 83.5%.The prevalences of doctor diagnosed asthma,hay fever,and pneumonia were 2.9%,3.6%,and 28.3%,respectively.Living close to a highway was a risk factor for current rhinitis(AOR 1.5,95%CI 1.2–1.8),eczema(AOR 1.7,95%CI 1.2–2.5),and diagnosed pneumonia(AOR 1.3,95%CI 1.0–1.6).Dampness problems in the home were associated with 50%–130%increases in the prevalences of asthma and allergy.Airing bed linen under sun-shine was protective,especially against rhinitis.Pet avoidance was consistently and significantly associated with asthma and allergy(AOR 1.3–2.4).Decoration of the home during children’s early life is a risk factor for current rhinitis(AOR 1.9,95%CI 1.3–2.9)and eczema(AOR 1.9,95%CI1.1–3.6).Risk factors for pneumonia were living in an apartment(AOR 1.4,95%CI 1.1–1.8),latex wall paint(AOR 1.3,95%CI 1.0–1.7),dampness(AOR 1.4–1.5),breast feeding\3 months(AOR 1.3,95%CI 1.0–1.7),never airing bed linen in sunshine(AOR 1.3,95%CI1.3–1.6),and cleaning children’s room less frequently than once per day(AOR 1.4,95%CI 1.1–1.7).This study demonstrates that home indoor environmental and life style factors may influence the health of children in Xi’an.展开更多
Recent studies have declared that members of the ss DNA virus family Microviridae play an important role in multiple environments, as they have been found taking a dominant position in the human gut. The aim of this s...Recent studies have declared that members of the ss DNA virus family Microviridae play an important role in multiple environments, as they have been found taking a dominant position in the human gut. The aim of this study was to analyze the overall composition of the gut virome in coronary heart disease(CHD) patients, and try to discover the potential link between the human gut virome and CHD. Viral metagenomics methods were performed to detect the viral sequences in fecal samples collected from CHD inpatients and healthy persons as controls. We present the analysis of the virome composition in these CHD patients and controls. Our data shows that the virome composition may be linked to daily living habits and the medical therapy of CHD.Virgaviridae and Microviridae were the two dominant types of viruses found in the enteric virome of CHD patients. Fourteen divergent viruses belonging to the family Microviridae were found, twelve of which were grouped into the subfamily Gokushovirinae, while the remaining two strains might represent two new subfamilies within Microviridae, according to the phylogenetic analysis. In addition, the genomic organization of these viruses has been characterized.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
文摘Considering the variations in imaging sizes of the unmanned aerial vehicles(UAV)at different aerial photography heights,as well as the influence of factors such as light and weather,which can result in missed detection and false detection of the model,this paper presents a comprehensive detection model based on the improved lightweight You Only Look Once version 8s(YOLOv8s)algorithm used in natural light and infrared scenes(L_YOLO).The algorithm proposes a special feature pyramid network(SFPN)structure and substitutes most of the neck feature extraction module with the Special deformable convolution feature extraction module(SDCN).Moreover,the model undergoes pruning to eliminate redundant channels.Finally,the non-maximum suppression algorithm of intersection-union ratio based on minimum point distance(MPDIOU_NMS)algorithm has been integrated to eliminate redundant detection boxes,and a comprehensive validation has been conducted using the infrared aerial dataset and the Visdrone2019 dataset.The comprehensive experimental results demonstrate that when the number of parameters and floating-point operations is reduced by 30%and 20%,respectively,there is a 1.2%increase in mean average precision at a threshold of 0.5(mAP(0.5))and a 4.8%increase in mAP(0.5:0.95)on the infrared dataset.Finally,the mAP on the Visdrone2019 dataset has experienced an average increase of 12.4%.The accuracy and recall rates have seen respective increases of 9.2%and 3.6%.
基金The authors are grateful for the support of the Fundamental Research Funds of Research Institute of Forest New Technology,CAF(CAFYBB2019SY039).
文摘This study aims to realize the sharing of near-infrared analysis models of lignin and holocellulose content in pulp wood on two different batches of spectrometers and proposes a combined algorithm of SPA-DS,MCUVE-DS and SiPLS-DS.The Successive Projection Algorithm(SPA),the Monte-Carlo of Uninformative Variable Elimination(MCUVE)and the Synergy Interval Partial Least Squares(SiPLS)algorithms are respectively used to reduce the adverse effects of redundant information in the transmission process of the full spectrum DS algorithm model.These three algorithms can improve model transfer accuracy and efficiency and reduce the manpower and material consumption required for modeling.These results show that the modeling effects of the characteristic wavelengths screened by the SPA,MCUVE and SiPLS algorithms are all greatly improved compared with the full-spectrum modeling,in which the SPA-PLS result in the best prediction with RPDs above 6.5 for both components.The three wavelength selection methods combined with the DS algorithm are used to transfer the models of the two instruments.Among them,the MCUVE combined with the DS algorithm has the best transfer effect.After the model transfer,the RMSEP of lignin is 0.701,and the RMSEP of holocellulose is 0.839,which was improved significantly than the full-spectrum model transfer of 0.759 and 0.918.
文摘目的:探讨经脐单孔+1孔腹腔镜(single-incision plus one-port laparoscopic surgery,SILS+1)结直肠癌根治术的安全性及可行性。方法:回顾性分析2017年10月至2019年11月赣南医学院第一附属医院收治的8例进行经脐SILS+1结直肠癌根治术患者的临床资料。结果:8例结直肠癌患者手术均顺利完成,无中转开腹及增加戳卡孔数量,手术平均时间107(95~124)min,平均出血33(10~80)mL,2例患者出现术后发热,考虑术后吸收热可能,术后第3天自行退热,其余患者术后无明显外科并发症,术后1~3天胃肠道功能恢复,3~5天拔出腹腔引流管,术后住院时间约9.3(7~11)天。术后病理再次证实为结直肠腺癌,淋巴结检出平均数目为13.6(11~16)枚,均无围手术期严重并发症及死亡的发生。术后随访3~24个月,平均10个月,未发现肿瘤局部复发、腹壁戳孔切口种植转移。结论:经脐SILS+1结直肠癌根治术安全可行,创伤小,美容效果令人满意,但远期疗效有待进一步观察。
基金supported by the National Natural Science Foundation of China(92372117 and U22A20141)the National Key Research and Development Program of China(2023YFC3905904)+2 种基金Natural Science Foundation of Hunan Province(2022JJ20068)Natural Science Foundation of Changsha City(kq2208258)Innovation-Driven Project of Central South University(2023CXQD024)。
文摘Host-less lithium metal anode generally suffers from large volume changes and serious dendrite growth during cycling,which poses challenges for its practical application.Interpenetrating phase composites with continuous architectures offer a solution to enhance mechanical properties of materials.Herein,a robust composite Li anode(LBN)material is fabricated through the metallurgical reaction between Li and hexagonal boron nitride(h-BN)with the formation of interpenetrating LiB/Li_(3)BN_(2)phases.As LiB fibers are anchored by Li_(3)BN_(2)granules,the collapse and slippage of LiB fibers are suppressed whilst the mechanical strength and structural stability of LBN are reinforced.By rolling,ultrathin(15μm),freestanding,and electrochemically stable LBN foil can be obtained.The LBN anode exhibits a high average Coulombic efficiency of 99.69%(1 mA cm^(-2),3 mAh cm^(-2))and a long lifespan of 2500 h(1 mA cm^(-2),1 m Ah cm^(-2)).Notably,the LiCoO_(2)(with double-sided load 40 mg cm^(-2))|LBN pouch cell can operate over450 cycles with a capacity retention of 90.1%.The exceptional cycling stability of LBN can be ascribed to the interpenetrating reinforcement architectures and synergistic electronic/ionic conductivity of the LiB/Li_(3)BN_(2)dual-lithiophilic-phases.This work provides a new methodology for thin Li strip processing and reinforced-architecture design,with implications beyond battery applications.
基金supported by the Zhejiang Science and Technology Major Program on Agricultural New Variety Breeding(2021C02064-6)。
文摘Dear Editor,Sorghum(Sorghum bicolor[L.]Moench)(2n=20),a C4 droughttolerant cereal crop,is widely cultivated for food,feed,and biofuel,resulting in varieties with distinct morphological characteristics.The Sanger-sequencing-based sorghum reference genome of the inbred variety BTx623(grain sorghum)was initially released in 2009(base error<1 per 10 kb)(Paterson et al.,2009),and the most widely used version 3 assembly(base error<1 per 100 kb),consisting of 4773 contigs with 2679 unresolved gaps(~28 Mb)in 10 chromosomes,was improved by next-generation sequencing in 2017(McCormick et al.,2018).
文摘Infectious disease departments in hospitals require pressure gradient to create unidirectional airflow to prevent the spread of contaminants,typically by creating active air infiltration through the difference between supply and exhaust air volumes.The door gap is the channel of air flow between rooms,so its height has an important influence on the pressure difference and infiltration air volume of the room.There is still a lack of research on setting reasonable ventilation strategies according to the different heights of door gaps at different positions in the building.In this study,model of a set of isolation wards was established and analyzed using the multi-zone simulation software CONTAM,and the ventilation strategies with different heights of door gaps were applied to the actual infection diseases department.The results show that in a building with ventilation system divided by functional area,the difference in the height of the door gaps requires different active infiltration air volumes.Pressure fluctuations in the medical and patient corridors are greater than in other rooms.The significance of this study is to understand the active infiltration of air to guide the design and operation of ventilation systems in infectious disease hospitals or building remodeled to isolate close contacts of COVID-19 patients.It is also instructive for the design of pressure gradients in clean workshops,biological laboratories,and other similar buildings.
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Aeknowledgements This work was supported by the Major Scientific and Technological hmovation Projects of Hubci Province (No. 2014AAA001), the National Basic Research Program of China (Nos. 2014CB340100, 2014CB340101, and 2014CB340105). and the Natural Science Foundation of Hubei Prov incc (No. 2015CFA056).
文摘A few-mode fiber (FMF) is designed to support three spatial modes (LP01, LP 11a, and LP 11 b) and fabricated through plasma chemical vapor deposition (PCVD)and rod-in-tube (RIT) method. Using PDM-DFTS-OFDM- 32QAM modulation, wavelength division multiplexing, mode multiplexing, and coherent detection, we successfully demonstrated 200Tb/s (375× 3 × 178.125Gb/s) signal over 1 km FMF using C and L bands with 25 GHz channel spacing. After 1 km FMF transmission, all the tested bit error rates (BERs) are below 20% forward error correction (FEC) threshold (2.0 × 10-2). Within each sub-channel, we achieved a spectral efficiency of 21.375 bits/Hz in the C and L bands.
文摘Snail, a family of zinc finger transcription factors, plays an important role in morphogenesis and embryogenesis. Snail zinc finger family 2 (SNAI2 or Slug) has been demonstrated to regulate carcinogenesis of several human cancers including breast, prostate, head, neck,
基金supported by the National Natural Science Foundation of China (51178374)the Specialized Research Fund for the Doctoral Program of Higher Education (20106120110008)Xi’an Urban and Rural Construction Committee of Science and Technology Project (2011023)
文摘To assess associations between home indoor air environments and asthma,allergies and pneumonia,children aged 1–8 years were surveyed from 12 kindergartens in the city of Xi’an.2,020 questionnaires were responded with a response rate of 83.5%.The prevalences of doctor diagnosed asthma,hay fever,and pneumonia were 2.9%,3.6%,and 28.3%,respectively.Living close to a highway was a risk factor for current rhinitis(AOR 1.5,95%CI 1.2–1.8),eczema(AOR 1.7,95%CI 1.2–2.5),and diagnosed pneumonia(AOR 1.3,95%CI 1.0–1.6).Dampness problems in the home were associated with 50%–130%increases in the prevalences of asthma and allergy.Airing bed linen under sun-shine was protective,especially against rhinitis.Pet avoidance was consistently and significantly associated with asthma and allergy(AOR 1.3–2.4).Decoration of the home during children’s early life is a risk factor for current rhinitis(AOR 1.9,95%CI 1.3–2.9)and eczema(AOR 1.9,95%CI1.1–3.6).Risk factors for pneumonia were living in an apartment(AOR 1.4,95%CI 1.1–1.8),latex wall paint(AOR 1.3,95%CI 1.0–1.7),dampness(AOR 1.4–1.5),breast feeding\3 months(AOR 1.3,95%CI 1.0–1.7),never airing bed linen in sunshine(AOR 1.3,95%CI1.3–1.6),and cleaning children’s room less frequently than once per day(AOR 1.4,95%CI 1.1–1.7).This study demonstrates that home indoor environmental and life style factors may influence the health of children in Xi’an.
基金financially supported by the "2014 AgriX" Project Found of Shanghai Jiao Tong University(No. AF1500028/001)
文摘Recent studies have declared that members of the ss DNA virus family Microviridae play an important role in multiple environments, as they have been found taking a dominant position in the human gut. The aim of this study was to analyze the overall composition of the gut virome in coronary heart disease(CHD) patients, and try to discover the potential link between the human gut virome and CHD. Viral metagenomics methods were performed to detect the viral sequences in fecal samples collected from CHD inpatients and healthy persons as controls. We present the analysis of the virome composition in these CHD patients and controls. Our data shows that the virome composition may be linked to daily living habits and the medical therapy of CHD.Virgaviridae and Microviridae were the two dominant types of viruses found in the enteric virome of CHD patients. Fourteen divergent viruses belonging to the family Microviridae were found, twelve of which were grouped into the subfamily Gokushovirinae, while the remaining two strains might represent two new subfamilies within Microviridae, according to the phylogenetic analysis. In addition, the genomic organization of these viruses has been characterized.
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.