Establishment of image-guided radiotherapy of orthotopic hepatocellular carcinoma mouse model

Background:Hepatocellular carcinoma(HCC)is the most common type of liver cancer.Recently,developments in radiotherapy technology have led to radiotherapy becoming one of the main therapeutics of HCC.Therefore,a suitable animal model for radiotherapy of the orthotopic HCC mouse model is urgently needed.Methods:In the present study,Hepa1-6 cells were injected into the liver of C57BL/6 mice in situ to mimic the pathological characteristics of the original HCC.Tumor formation was monitored by applying magnetic resonance imaging techniques and verified by H&E histopathological staining,AFP staining,and Ki67 staining.A single dose of 10 Gy X-ray was applied to simulate clinical radiotherapy plans using image-guided radiotherapy(IGRT)equipment.The efficiency of radiotherapy was then assessed by examining tumor size and weight one week after radiation.Cleaved-caspase3 staining and TUNEL were used to assess apoptosis in tumor tissues.Results:Intrahepatic tumor development was detected in the liver according using MRI.A high-density shadow could be seen 10 days after cell injection,which indicated the formation of HCC in vivo.The tumors grew steadily bigger,and underwent precision radiotherapy 20 days after injection.The typical pathological characteristics of HCC,such as large,deeply stained nuclei and irregular cell size,were visible with H&E staining.After radiotherapy,significantly higher expression of the immunohistochemical markers Ki67 and AFP were detected in tumor tissue than in the nearby normal tissue.Compared with the control group,the tumor volume(p=0.05)and weight(p<0.05)of the irradiated group were significantly reduced.In addition,a higher frequency of apoptosis was identified in irradiated HCC tumor tissue using the TUNEL and cleaved-caspase3 staining assay.Conclusions:In a well-established orthotopic HCC model,MRI was utilized to monitor the formation of tumors,and IGRT was used to simulate clinical radiotherapy.The present study could provide a suitable preclinical system for HCC radiotherapyrelated studies.

Nitrogen uptake regime regulated by ice melting during austral summer in the Prydz Bay, Antarctica

Using a combination of stable isotope(15N) and radionuclide(226Ra) analyses, we examine possible controls on the interactions between melting ice and the uptake of nitrogen in the Prydz Bay during the 2006 austral summer.We find that specific rates of uptake for nitrate and ammonium correlate positively to their concentrations, thus suggesting a substrate effect. In the study area, we observe that regions along open, oceanic water have high fratios(nitrate uptake/nitrate+ammonium uptake), while areas near the Amery Ice Shelf have significantly low fratios. Further analysis reveals a negative correlation between the f-ratio and the melt water fraction, thus implying that the melting of ice plays an essential role in regulating pelagic N dynamics in the Southern Ocean(SO). Stratification, produced by melting ice, should profoundly affect the efficiency of the SO’s biological pump and consequently affect the concentration of CO2 in the atmosphere. Results presented in this study add information to an already significant base of understanding of the controls on pelagic C and N dynamics in the SO. This provides unique insights for either interpreting past changes in geologic records or for predicting future climate change trends.

基于ARM嵌入式技术的汽车智能防盗防爆胎报警系统

随着国民经济的增长,汽车的使用也逐渐普及开来,因而产生的汽车被盗事件及车胎爆炸引发的安全事故时有发生。针对这一问题,人们对汽车的安全智能化提出了更高的要求。然而,现在很多汽车防盗装置存在价格高、灵敏度低等缺点。因此,我们提出了一种绿色、环保、经济的基于ARM的汽车智能防盗防爆胎报警系统。本系统以ARM嵌入式技术为核心,采用多种传感器对车身的状况进行检测,通过感测技术将车辆的状态信息实时地传入微处理器中,再由微处理器对这些状态信息进行分析处理,由此实现对汽车的封锁、定位、报警等功能。通过ARM嵌入式技术改良的汽车防盗防爆胎报警系统更加智能安全,更能保障车子及司机行车的安全,无疑具有广泛的应用前景。

Chaperone-and PTM-mediated activation of IRF1 tames radiation-induced cell death and the inflammatory response

The key role of structural cells in immune modulation has been revealed with the advent of single-cell multiomics,but the underlying mechanism remains poorly understood.Here,we revealed that the transcriptional activation of interferon regulatory factor 1(IRF1)in response to ionizing radiation,cytotoxic chemicals and SARS-CoV-2 viral infection determines the fate of structural cells and regulates communication between structural and immune cells.Radiation-induced leakage of mtDNA initiates the nuclear translocation of IRF1,enabling it to regulate the transcription of inflammation-and cell death-related genes.Novel posttranslational modification(PTM)sites in the nuclear localization sequence(NLS)of IRF1 were identified.Functional analysis revealed that mutation of the acetylation site and the phosphorylation sites in the NLS blocked the transcriptional activation of IRF1 and reduced cell death in response to ionizing radiation.Mechanistically,reciprocal regulation between the single-stranded DNA sensors SSBP1 and IRF1,which restrains radiation-induced and STING/p300-mediated PTMs of IRF1,was revealed.In addition,genetic deletion or pharmacological inhibition of IRF1 tempered radiation-induced inflammatory cell death,and radiation mitigators also suppressed SARS-CoV-2 NSP-10-mediated activation of IRF1.Thus,we revealed a novel cytoplasm-oriented mechanism of IRF1 activation in structural cells that promotes inflammation and highlighted the potential effectiveness of IRF1 inhibitors against immune disorders.

COX-2 in lung cancer:Mechanisms,development,and targeted therapies

Lung cancer(LC)is the leading cause of cancer-related death worldwide,with non-small cell lung cancer(NSCLC)comprising 85%of all cases.COX-2,an enzyme induced significantly under stress conditions,catalyzes the conversion of free arachidonic acid into prostaglandins.It exhibits high expression in various tumors and is closely linked to LC progression.COX-2 functions as a pivotal driver in cancer pathogenesis by promoting prostaglandin E2 synthesis and facilitating tumor cell occurrence and development.Furthermore,COX-2 holds potential as a predictive marker for early-stage NSCLC,guiding targeted therapy in patients with early COX-2 overexpression.Additionally,combining COX-2 inhibitors with diverse treatment modalities enhances tumor therapeutic efficacy,minimizes adverse effects on healthy tissues,and improves overall patient survival rates posttreatment.In conclusion,combined therapy targeting COX-2 presents a promising novel strategy for NSCLC treatment,offering avenues for improving prognosis and effective tumor treatment.This review provides novel insights and ideas for developing new treatment strategies to improve the prognosis of NSCLC.

Characterization of time-and size-dependent particle emissions and decay from cooking oil fumes in residence:Impacts of various intervention measures

The dynamic characteristics of cooking-related particle size distributions in real-world settings are not fully understood.Through a real-world campaign in a naturally-ventilated apartment in the northwest US,this study investigates the temporal profiles of size-resolved particle number concentrations(PNCs)ranging from 0.3 to 10µm from frying cooking activities.The cooking scenarios included various combinations of window ventilation,venting range hood(VRH)use,and portable air cleaner(PAC)utilization.Following a standardized pan-frying protocol throughout seven scenarios,real-time PNCs of 16-size bins were measured in the kitchen.The PNCs were empirically compared among size bins,periods,and scenarios.The most abundant size ranges of cooking-related particles were 0.3–0.579µm in number(45%–71%of the total)and 2.685–5.182µm in mass(48%–57%of the total).Compared with the scenario without any cooking-fume mitigating measures,keeping the kitchen windows open reduced the mean PNCs during and within 1-h after cooking for PM_(0.3-2.5),PM_(2.5-10),and PM_(0.3-10)by 78%,92%,and 79%,respectively.By contrast,utilizing a VRH during cooking reduced the corresponding levels by 21%,69%,and 25%,respectively.Combined with running the VRH,using a PAC in the kitchen led to additional reductions of 84%,88%,and 84%,respectively.Additionally,the removal efficiencies of the three strategies generally increased with particle sizes.

Cryptosporidiosis threat under climate change in China:prediction and validation of habitat suitability and outbreak risk for human-derived Cryptosporidium based on ecological niche models

Background Cryptosporidiosis is a zoonotic intestinal infectious disease caused by Cryptosporidium spp.,and its transmission is highly influenced by climate factors.In the present study,the potential spatial distribution of Cryptosporidium in China was predicted based on ecological niche models for cryptosporidiosis epidemic risk warning and prevention and control.Methods The applicability of existing Cryptosporidium presence points in ENM analysis was investigated based on data from monitoring sites in 2011–2019.Cryptosporidium occurrence data for China and neighboring countries were extracted and used to construct the ENMs,namely Maxent,Bioclim,Domain,and Garp.Models were evaluated based on Receiver Operating Characteristic curve,Kappa,and True Skill Statistic coefficients.The best model was constructed using Cryptosporidium data and climate variables during 1986‒2010,and used to analyze the effects of climate factors on Cryptosporidium distribution.The climate variables for the period 2011‒2100 were projected to the simulation results to predict the ecological adaptability and potential distribution of Cryptosporidium in future in China.Results The Maxent model(AUC=0.95,maximum Kappa=0.91,maximum TSS=1.00)fit better than the other three models and was thus considered the best ENM for predicting Cryptosporidium habitat suitability.The major suitable habitats for human-derived Cryptosporidium in China were located in some high-population density areas,especially in the middle and lower reaches of the Yangtze River,the lower reaches of the Yellow River,and the Huai and the Pearl River Basins(cloglog value of habitat suitability>0.9).Under future climate change,non-suitable habitats for Cryptosporidium will shrink,while highly suitable habitats will expand significantly(χ^(2)=76.641,P<0.01;χ^(2)=86.836,P<0.01),and the main changes will likely be concentrated in the northeastern,southwestern,and northwestern regions.Conclusions The Maxent model is applicable in prediction of Cryptosporidium habitat suitability and can achieve excellent simulation results.These results suggest a current high risk of transmission and significant pressure for cryptosporidiosis prevention and control in China.Against a future climate change background,Cryptosporidium may gain more suitable habitats within China.Constructing a national surveillance network could facilitate further elucidation of the epidemiological trends and transmission patterns of cryptosporidiosis,and mitigate the associated epidemic and outbreak risks.

Accelerated oxidation of VOCs via vacuum ultraviolet photolysis coupled with wet scrubbing process

Vacuum ultraviolet(VUV) photolysis is a facile method for volatile organic compounds(VOCs) elimination, but is greatly limited by the relatively low removal efficiency and the possible secondary pollution. To overcome above drawbacks, we developed an efficient method for VOCs elimination via VUV photolysis coupled with wet scrubbing process. In this coupled process, volatile toluene, a representative of VOCs, was oxidized by the gas-phase VUV photolysis, and then scrubbed into water for further oxidation by the liquid-phase VUV photolysis. More than 96% of toluene was efficiently removed by this coupled process, which was 2 times higher than that in the gas-phase VUV photolysis. This improvement was attributed to the synergistic effect between gas-phase and liquid-phase VUV photolysis. O3and HO·are the predomination reactive species for the toluene degradation in this coupled process, and the generation of O3in gas-phase VUV photolysis can efficiently enhance the HO·production in liquid-phase VUV photolysis. The result from in-situ proton transfer reaction ionization with mass analyzer(PTR-MS) further suggested that most intermediates were trapped by the wet scrubbing process and efficiently oxidized by the liquid-phase VUV photolysis, showing a high performance for controlling the secondary pollution. Furthermore, the result of stability test and the reuse of solution demonstrated that this coupled process has a highly stable and sustainable performance for toluene degradation. This study presents an environmentally benign and highly efficient VUV photolysis for gaseous VOCs removal in the wet scrubbing process.

Steady-state model for predicting size-resolved gas-particle partitioning of semi-volatile organic compounds (SVOCs) in indoor environments

Semi-volatile organic compounds(SVOCs)are ubiquitous and important pollutants in indoor environments.The strong partition between gas phase and suspended particles has significant effects on the transport,human exposure via inhalation,and control strategies of indoor SVOCs.Several models have been developed to simulate the gas–particle partitioning of indoor SVOCs,including a steady-state model by expanding the steady-state model suitable for the outdoor environment to indoor environments.However,the effects of two important indoor environment-specific parameters,i.e.,the particle size distribution(PSD)and the air-change rate(ACH),were not considered in the existing steady-state model,leading to the inaccurate predictions among buildings.To solve this problem,this study developed a novel steady-state model to more comprehensively simulate the gas-particle partitioning of indoor SVOCs by incorporating the effects of PSD and ACH.Better agreement between the predictions of the novel model and the results collected via both field tests and laboratory tests(retrieved from two different studies)supported the effectiveness of the improvements in the novel model.Sensitivity analysis further supported the necessity of involving PSD and ACH.Further implications of the novel model were also discussed.This study should be helpful for deepening the understanding and accurate simulation of the gas-particle partitioning,as well as the transport and human exposure via inhalation,of indoor SVOCs.

Cyclospora cayetanensis infections among diarrheal outpatients in Shanghai： a retrospective case study

Cyclospora cayetanensis is a foodborne and waterborne pathogen that causes endemic and epidemic human diarrhea worldwide. A few epidemiological studies regarding C. cayetanensis infections in China have been conducted. During 2013, a total of 291 stool specimens were collected from patients with diarrhea at a hospital in urban Shanghai. C. cayetanensis was not detected in any of the stool specimens by traditional microscopy, whereas five stool specimens （1.72%, 5/291） were positive by PCR. These positive cases confirmed by molecular technology were all in the adult group （mean age 27.8 years; 2.94%, 5/170） with watery diarrhea. Marked infection occurred in the rainy season of May and July. Sequence and phylogenetic analyses of the partial 18S rRNA genes of C. cayetanensis isolated showed intra-species diversity of this parasite. This study showed, for the first time, that C. cayetanensis is a pathogen in outpatients with diarrhea in Shanghai, albeit at a low level. However, the transmission dynamics of this parasite in these patients remain uncertain.

The Chinese ‘‘HumanFlesh’’ Web:the first decade and beyond

Human flesh search(HFS), a Web-enabled crowdsourcing phenomenon, originated in China a decade ago. In this article, we present the first comprehensive empirical analysis of HFS, focusing on the scope of HFS activities, the patterns of HFS crowd collaboration process, and the characteristics of HFS participant networks. A survey of HFS participants was conducted to provide an in-depth understanding of the HFS community and various factors that motivate these participants to contribute. This article also advocates a new stream of Web science and social computing research that will be important in predicting the future growth and use of the World Wide Web.

Wildlife-borne microorganisms and strategies to prevent and control emerging infectious diseases

China is one of the countries with the richest wildlife population.The large variety of widely distributed species act as natural or susceptible hosts for numerous infectious diseases.It is estimated that there are more than 1.2 million unknown virus species in China,and there might be 10,000–30,000 unknown bacteria in wild mammals on the Qinghai-Tibet Plateau alone.There are no less than 600,000 species of animal-borne parasites and approximately 2 million species of fungi worldwide.With rapid economic growth and globalization,humans and wildlife interact more frequently,which enhances the probability of wildlife-borne pathogens infecting humans.The occurrence of animal-borne infectious diseases will become the“new normal”we have to face in the future.Therefore,research should be carried out on wildlife-borne microorganisms and the prevention and control of emerging infectious diseases to establish an analytical framework and an evaluation technology system for risk assessment and early warning of potential animal-borne emerging infectious diseases.This will not only improve our understanding of wildlife-borne microbial communities but also enable in-depth analysis,discovery,early warning,and even prediction of major animal-borne emerging infectious diseases that might occur in the future.Furthermore,this research will reduce response times,minimize the social and economic impact and losses,enable interventions related to the emergence or spread of the disease as early as possible,and comprehensively improve our management of infectious disease outbreaks.

Intestinal Protozoan Infections in Patients with Diarrhea—Shanghai Municipality,Zhenjiang City,and Danyang City,China,2011–2015 and 2019–2021

Summary What is already known about this topic?Intestinal protozoa are common pathogens of diarrhea globally.However,the etiology of diarrhea due to intestinal protozoan infections in China is not known.What is added by this report?Based on active syndromic surveillance in Shanghai,Zhenjiang,and Danyang during 2011–2015 and 2019–2021,89(1.67%)patients were infected with intestinal protozoa(Cryptosporidium spp.,Giardia duodenalis,Enterocytozoon bieneusi,and Cyclospora cayetanensis),and positivity rates statistically differed by region and age.What are the implications for public health practice?This was the most comprehensive data collection in investigating parasitic diarrheal diseases in humans.Identification of these protozoa in diarrhea will provide new perspectives for detecting hidden etiological agents of diarrhea as early as possible.

Single-cell RNA sequencing reveals the cell landscape of a radiation-induced liver injury mouse model

The mechanisms of radiation-induced liver injury(RILI)has not been fully elucidated so far.In the present study,a RILI mouse model was constructed by exposing the liver to a single dose of 30 Gy X-rays.Liver injuries consisting of liver function damage and histopathological variations were confirmed after 2 weeks.And then the cellular atlas of RILI liver was generated by profiling 9,641 cells isolated from X-ray irradiated mice livers and control ones from RILI mice model using single-cellRNAsequencing(scRNA-seq).Seven cell types were identified,including B cells,natural killer cells,T cells,macrophages/Küpffer cells/Dendritic cells(DC),neutrophils,endothelial cells,and hepatocyte.Although there was no significant difference of overall cell typing was observed between the Control and RILI groups,hepatocytes and macro/Küpffer/DC cell types were chosen for further functional exploration.Gene expression profiles and bioinformatics analysis of hepatocytes revealed that multiple metabolic related pathways were enriched in livers exposed to IR.These scRNA-seq data were confirmed in RILI liver samples via adipose staining.Besides,obviously varied M1-/M2-macrophages polarization was observed in RILI liver,which was in accordance with the enzyme linked immunosorbent assay(ELISA)results of IR-induced M2 to pro-inflammatory M1 macrophages transformation in mouse macrophage cell line Raw264.7.In addition,we predicted that several genes were found to differentially expressed during the process of macrophage polarization from M2 to M1 subtype.Overall,our study provides a cellular landscape of RILI at single-cell resolution that indicates the characteristics of hepatocytes and macrophages,which will contribute to investigate the novel therapeutic or preventive management for RILI.

Study of the decorporation efficacy and toxicity of tetradentate 3-hydroxy- 2-pyridinone ligands at the cellular level

Objective:A series of experiments were carried out to study the comparative decorporation efficacy and toxicity of three tetradentate hydroxypyridinone ligands(3LI-1-Cm-3,2-HOPO,5LIO-1-Cm-3,2-HOPO,and 7LIO-1-Cm-3,2-HOPO)with the variation of the linker length and the substituents.Methods:Three ligands were obtained from a 4-step synthesis via the amidation of HOPO unit and different backbones.Potentiometric titrations were carried out to evaluate the formation constants of their corresponding uranyl complexes.CCK-8 and colony formation assays were used to compare the cytotoxicity of the three ligands and uranyl using renal proximal tubular epithelial(NRK-52E)cells.In vitro uranium removal assays were performed to assess decorporation efficiencies of those ligands by co-incubating uranium and chelators with NRK-52E cells for 48 h.Results:Among the three ligands,5LIO-1-Cm-3,2-HOPO exhibits the highest uranyl affinity(logβ110?18.6(7))in comparison to the other two ligands(logβ110?14.9(2)for 3LI-1-Cm-3,2-HOPO and logβ110?16.7(1)for 7LIO-1-Cm-3,2-HOPO).The results of CCK-8 tests and colony formation assays further elucidate that 5LIO-1-Cm-3,2-HOPO and 7LIO-1-Cm-3,2-HOPO both show a similar level of cytotoxicity compared with ZnNa3-DTPA at relatively low ligand concentrations.In contrast,in the 3LI-1-Cm-3,2-HOPO treated group,the cell viability decreased markedly with the increase of the ligand concentrations,and the colony formation capability of NRK-52E cells was inhibited.Furthermore,the comparative decorporation efficacy of the three ligands was obtained from in vitro uranium removal assays,suggesting that these ligands could significantly inhibit the cellular uptake and prompt the cellular release of uranium from NRK-52E cells by the level of 81.9%,91.8%,and 87.1%,respectively.Conclusion:Our current results demonstrate that the linker/backbone species would significantly affect the decorporation efficacy and toxicity of the tetradentate 3-hydroxy-2-pyridinone ligands,which is informative for the future design and modification of novel decorporation ligands.

To minimize radiation therapy toxicity to the skin

As the largest organ,the skin functions as an effective physical and immunological barrier against external stimulation.However,skin is a constantly renewed tissue that contains basal keratinocytes,hair follicle stem cells,and melanocytes,which are highly susceptible to ionizing radiation.1 To date,radiotherapy is one of the leading treatment modalities for various cancers.Radiation-induced skin injury(RSI)occurs in about 95%of cancer patients who receive radiotherapy.2 And the pathological feature varies from erythema to epilation,ulceration,and gangrene.2 The wide-spread application of ionizing radiation in industry,medicine,science,the military and nuclear facilities has significantly increased the potential of RSI,which may be different from these who receive radiotherapy.3 RSI seriously affect the patients’quality of life。

Respiratory flora:The potential biomarker of radiation-induced pulmonary injury

Radiation-induced pulmonary injury is a major dose-limiting toxicity that occurs due to thoracic radiotherapy.And the most widely used high-throughput technology,16S ribosomal RNA sequencing,is adopted for bacterial classification and identification of airway microbiome analysis.In this study,we provide novel insights into the composition pattern and predicted function of the lung microbiome in RIPI rats.Certain genus and species change in a dose-dependent manner,which might be capable of serving as novel bacterial biomarkers,as well as the potential targets for the future diagnosis or treatment of RIPI.In summary,our findings provide a vital reference for RIPI study,and will contribute to investigate the novel therapeutic or preventive management for RIPI.

Combining radiation with immune checkpoint inhibitors therapy for HCC: From the alteration of the immune microenvironment by radiotherapy

Hepatocellular carcinoma(HCC),one of the deadliest cancers all over the world,had a limited prognosis in the past.Recently,the remarkable efficacy of immune checkpoint inhibitors(ICIs)therapy has been shown in various solid tumors.What's more,the occurrence of HCC is associated with immune escape and therefore various ICIs have been applied to clinical trials for HCC.However,the special immune environment of the liver creates the complex tumor microenvironment(TME)of HCC,which impairs the overall survival(OS)and overall response rate(OCR)of ICIs as a monotherapy.Lately,various therapies have been used in combination with ICIs therapy to improve its clinical efficacy.Among which,radiotherapy is widely concerned because of its unique immunoreaction.A large number of basic and clinical studies have demonstrated that the combined radiotherapy and ICIs therapy has advantages in improving the OCR and efficacy,as compared with ICIs therapy alone.Herein,this article reviews the studies on the advantages and possible mechanisms of the combination of radiotherapy and ICIs therapy for HCC.

From the Editors-in-Chief

Radiation Medicine and Protection is an international journal covering multidisciplinary fields.Since Roentgen discovered X-rays in 1895,ionizing radiation has widespread application in medicine,including diagnostic radiology,radiotherapy,nuclear medicine and interventional procedures.However,radiation is a double-edged sword.Radiationinduced injury has been a matter of concern of the public,patients and medical staff.How to balance the benefit and the cost factors of radiation requires thorough exploration by professionals in the areas of radiation biology,radiology,radiation therapy,health physics/dosimetry and radiation epidemiology.

Ambient formaldehyde concentrations in summer in 30 Chinese cities and impacts on air cleaning of built environment

Formaldehyde is an important carcinogen commonly found indoors.Its indoor sources have been intensively in-vestigated.But study on outdoor formaldehyde concentration,which is potentially an important source to indoors,remains scarce.This study attempts to characterize temporal and spatial distribution of the atmospheric formalde-hyde concentration in Chinese cities.Diurnal variation of ambient formaldehyde was examined in 6 cities and peak hours were identified between 12:00 pm and 3:00 pm.Consequently,outdoor formaldehyde concentrations were measured in the peak hours in 30 cities during the summer months of Jul.-Aug.,2022.The formaldehyde concentrations in the peak hours fell into a range of 0.005-0.087 mg/m^(3)(median value is 0.027 mg/m^(3)),87.7%of which have exceeded the chronic reference exposure criteria of 0.009 mg/m^(3) set by Office of Environmental Health Hazard Assessment.Health risk analysis suggests that exposure to ambient formaldehyde could cause a median carcinogenic risk of 1.9×10^(−5)(3.17×10^(−6)-6.13×10^(−5)),higher than threshold limit of 10−6.Pearson correlation analysis of the 30 cities shows that ambient summertime atmospheric formaldehyde concentrations of the city are positively correlated with its Gross Domestic Product(r=0.48).We also found that the outdoor formaldehyde concentrations in urban areas(median:0.017 mg/m^(3))is slightly higher than those in suburban areas(median:0.013 mg/m^(3)).Results here prove that outdoor formaldehyde is ubiquitous in Chinese cities and reduces effectiveness of ventilation in dilution indoor concentrations.Neglecting it would underestimate air cleaner capacity needed by a factor of about two.It should be accounted for in health analysis and air quality engineering control design of built environment in the future.