Imperative for long-term management and surveillance in Kawasaki disease

Kawasaki disease(KD)is a significant pediatric vasculitis known for its potential to cause severe coronary artery complications.Despite the effectiveness of initial treatments,such as intravenous immunoglobulin,KD patients can experience long-term cardiovascular issues,as evidenced by a recent case report of an adult who suffered a ST-segment elevation myocardial infarction due to previous KD in the World Journal of Clinical Cases.This editorial emphasizes the critical need for long-term management and regular surveillance to prevent such complications.By drawing on recent research and case studies,we advocate for a structured approach to follow-up care that includes routine cardiac evaluations and preventive measures.

Performance of brain MRI of a two generation father-and-son family with long-term smoking caffeinum natrio benzoicum

Since the 1970s, some people in north, northeast,northwest areas began to smoke caffeinum natrio benzoicum （CNB） and started to abuse CNB. As a common ingredient that can be found in drugs or drinks,many studies on the safety of CNB have been investigated, but no one has shown significant abnormality in the brain of a CNB abuser by using neuroimaging. In our study, three subjects from of a two generation father-and-son family with long-term smoking CNB were enrolled. Combining with the clinical data and taking the cocaine animal trial model and toxicology as the reference, we wanted to observe the performance of brain MRI and MRS of patients with long-term smoking CNB.

Long-term Trends and Predictors of Smoking Behaviors among Men Following First-ever Ischemic Stroke

Continued smoking following stroke is associated with adverse outcomes including increased risk of mortality and secondary stroke. The aim of this study was to examine the long-term trends in smoking behaviors and factors associated with smoking relapse among men who survived their first-ever stroke. Data collection for this longitudinal study was conducted at baseline through face-toface interviews and follow-up was completed every 3 months via telephone, beginning in 2010 and continuing through 2014. Cox proportional hazard regression models were used to identify predictors of smoking relapse behavior. At baseline, 372 male patients were recruited into the study. Totally, 155(41.7%) of these patients stopped smoking for stroke, and 61(39.3%) began smoking again within 57 months after discharge with an increasing trend in the number of cigarettes smoked per day. Exposure to environmental tobacco smoke at places outside of home and work(such as bars, restaurants)(HR, 2.34; 95% CI, 1.04–5.29, P=0.04), not having a spouse(HR, 0.12; 95% CI, 0.04–0.36; P=0.0002) and smoking at least 20 cigarettes per day before stroke(HR, 2.42; 95% CI, 1.14–5.14, P=0.02) were predictors of smoking relapse. It was concluded that environmental tobacco smoke is an important determinant of smoking relapse among men who survive their first stroke. Environmental tobacco smoke should be addressed by smoke-free policies in public places.

Impact of baseline smoking status on long-term prognosis of patients with coronary artery disease underwent percutaneous coronary intervention:a large single-center data

Objective This study analyzed a large single-center sample in China to explain the impact of smoking state at baseline on long-term prognosis of coronary artery disease (CAD) patients who received percutaneous coronary intervention (PCI).

Long-term spatial memory and morphological changes in hippocampus of Wistar rats exposed to smoke from Carica papaya leaves

Objective:To investigate the effects of smoking of dried leaves of Carica papaya(pawpaw)based on ethnopharmacological information which indicated that smoking of papaya leaves could influence motor performance and learning.Methods:Twenty-four rats were used for the study,and were grouped into four groups.Groups 1served as the control(not exposed to papaya leaves smoke),while Groups 2,3 and 4 were exposed to smoke from 6.25 g,12.50 g and 18.75 g of dry pawpaw leaves respectively in a smoking chamber twice daily for 21 d with each exposure lasting for 3 min.Lastly,hippocampus was harvested in each group for histological study.Result:The results showed that there were significant(P<0.05)increases in mean of recall latencies of long-term spatial memory in the animal administered the high dose while the other groups had significantly(P<0.05)lower frequencies.Histological investigation showed signs of mild neural degeneration in high dose group and hypochromic appcarance of the Nissl substance in all treated groups.Conclusions:In conclusion,the findings from this study has demonstrated that smoking of papaya leaves has the ability to maintain an intact long-term spatial memory at all doses but retrieving such memory is faster with the low and medium dosages.

Smoking Cessation with E-Cigarettes in Smokers with a Documented History of Depression and Recurring Relapses

The association between nicotine dependence and affective disorders, particularly major depressive disorder (MDD), is well known with high prevalence rates being reported for smokers. The reason for this association is not clear, but, it has been argued that smoking may help individuals to cope with stress or medicate depressed mood. Smoking cessation programs are useful in helping smokers to quit, but smoking is a very difficult addiction to break, especially for people suffering from depression, and the need for novel and effective approaches to smoking cessation interventions for this special population is unquestionable. The e-cigarette is a battery-powered electronic nicotine delivery device (ENDD), which may help smokers to remain abstinent during their quit attempt. Here, we report for the first time objective measures of smoking cessation in two heavy smokers, suffering from depression, who experimented the e-cigarette.

Clinical manifestations,diagnosis and long-term prognosis of adult autoimmune enteropathy:Experience from Peking Union Medical College Hospital

BACKGROUND Autoimmune enteropathy(AIE)is a rare disease whose diagnosis and long-term prognosis remain challenging,especially for adult AIE patients.AIM To improve overall understanding of this disease’s diagnosis and prognosis.METHODS We retrospectively analyzed the clinical,endoscopic and histopathological characteristics and prognoses of 16 adult AIE patients in our tertiary medical center between 2011 and 2023,whose diagnosis was based on the 2007 diagnostic criteria.RESULTS Diarrhea in AIE patients was characterized by secretory diarrhea.The common endoscopic manifestations were edema,villous blunting and mucosal hyperemia in the duodenum and ileum.Villous blunting(100%),deep crypt lymphocytic infiltration(67%),apoptotic bodies(50%),and mild intraepithelial lymphocytosis(69%)were observed in the duodenal biopsies.Moreover,there were other remarkable abnormalities,including reduced or absent goblet cells(duodenum 94%,ileum 62%),reduced or absent Paneth cells(duodenum 94%,ileum 69%)and neutrophil infiltration(duodenum 100%,ileum 69%).Our patients also fulfilled the 2018 diagnostic criteria but did not match the 2022 diagnostic criteria due to undetectable anti-enterocyte antibodies.All patients received glucocorticoid therapy as the initial medication,of which 14/16 patients achieved a clinical response in 5(IQR:3-20)days.Immunosuppressants were administered to 9 patients with indications of steroid dependence(6/9),steroid refractory status(2/9),or intensified maintenance medication(1/9).During the median of 20.5 months of followup,2 patients died from multiple organ failure,and 1 was diagnosed with non-Hodgkin’s lymphoma.The cumulative relapse-free survival rates were 62.5%,55.6%and 37.0%at 6 months,12 months and 48 months,respectively.CONCLUSION Certain histopathological findings,including a decrease or disappearance of goblet and Paneth cells in intestinal biopsies,might be potential diagnostic criteria for adult AIE.The long-term prognosis is still unsatisfactory despite corticosteroid and immunosuppressant medications,which highlights the need for early diagnosis and novel medications.

Acute effect of smoking on gallbladder emptying and refilling in chronic smokers and nonsmokers: A sonographic study

AIM: To ultrasonographicaly evaluate the acute effects of smoking on gallbladder contraction and refilling in chronic smokers and nonsmokers.METHODS: Fifteen chronic smokers (21-30 years old) and fifteen nonsmokers (21-35 years old) participated in this study. Chronic smokers were selected among the volunteers who had been smoking for at least 5 years and 10 cigarettes per day (mean 17.5/d). Examinations were performed in two separate days. In the fi rst day, basal gallbladder (GB) volumes of volunteers were measured after 8-h fasting. After the examinations, participants had a meal containing at least 30-40 gram fat. Gallbladder volume was assessed at 5, 15, 30, 60, 120 and 180 min after the meal. In the second day, participants smoked 2 cigarettes after 8-h fasting. Then, they had the same meal, and gallbladder measurements were repeated at the same time points. Same procedures were applied to both groups. RESULTS: The mean starving GB volumes were 23.3 ± 3.3 mL in the fi rst day, 21.9 ± 3.0 mL in the second day in nonsmoker group and 18.3 ± 3.0 mL in the fi rst day, 19.5 ± 2.8 mL in second day in smoker group. There was no significant difference between starving GB volumes. We did not fi nd any signifi cant difference between the GB volumes measured at 5, 15, 30, 60, 120 and 180 min in the fi rst and second days in nonsmoker group. In smokers, post cigarette GB volume was found significantly higher at 5, 15 and 30 min which corresponded to GB contraction phase (P < 0.05). Control GB volume measurements were not signifi cantly different between the two groups. Post-smoking GB volumes were also not signifi cantly different between the two groups.CONCLUSION: Smoking prolongs the maximal GB emptying time both in smokers and in nonsmokers though it is not signifi cant. It delays GB contraction inchronic smokers and causes a signifi cant decrease in GB emptying volume. Smoking causes no signifi cant delay in GB refi lling in both smokers and nonsmokers. These effects of smoking observed in acute phase result in bile stasis in GB. Bile stasis is the underlying cause of most GB disorders in chronic process.

An Analysis on Failure Reasons of Quit Smoking among Smokers in Beijing Communities——Based on a Cross-Sectional Study

With the implementation of tobacco control policies and increasing publicity year by year,smokers have acquired more information and knowledge through various channels about the harmful effects of smoking.As a result,more smokers have developed a desire to quit smoking and have begun to try to quit.

The Impact of Electronic Cigarettes (e-Cigs) Smoking Habit on Periodontal Status and Salivary pH among Some Passive e-Cigs Smokers Referred to the College of Dentistry Clinics, King Khalid University

Background: Electronic cigarette (e-cigs) smoking is substitutional to traditional cigarette smoking to reduce the dangerous combustion of products. Moreover, passive smoking is involuntarily tobacco smoking due to the exposure to cigarette or tobacco smoke among non-smokers and due to there being little knowledge about the impact of passive e-cigs smoking on periodontal status and salivary pH. Therefore, the present study aimed to evaluate the effect of e-cigs smoking habit on periodontal tissue and salivary pH among some passive e-cigs smokers referred to the college of dentistry clinics, King Khalid University. Material and Methods: Ninety male participants who were referred to the college of dentistry clinics at King Khalid University were included in the study. Age, gender, e-cigs smoking, and general health were recorded. The participants were divided into three equal groups (n = 30) as follows: Group I (Non-passive e-cigs smokers and non-smokers) as the control group, Group II (e-cigs users), and Group III (Passive e-cigs smokers). Salivary pH, plaque control record (PCR), gingival bleeding index (GBI), clinical attachment loss (CAL), percentage of radiographic bone loss (% RBL), periodontal pocket depth (PPD), more than 5 missing teeth due to periodontal diseases (>5 MTDP), tooth mobility (TM), furcation involvement (FI), Bite collapse (BC), and less than 20 remaining teeth (10 Opposing pairs) (L20RT) as well as HbA1c were recorded. ANOVA test was used to the comparison between Groups I, II, and III in the participants’ ages and periodontitis staging clinical findings. The mean of participants’ age groups, the mean of salivary pH values of study groups, and the periodontitis staging complexity and HbA1c were compared between groups with the ANOVA test, Tukey’s test, and the chi-square test. P-value was recorded, and less than 0.5 was considered a statistically significant difference (p Results: The e-cigs users group revealed higher means of PCR, GBI %RBL values, and the participants percentages of >5 MTDP, TM, FI, L20RT, and diabetes mellitus (DM) among participants compared to the passive e-cigs smokers group and control group except for the participants percentage of BC among the participants, which was higher among the control group participants. The differences were not significant in PCR, GBI, %RBL and DM (p > 0.5) and significant in >5 MTDP, TM, FI, L20RT and smoking (p 7% values compared to the e-cigs users group and control group participants. The differences were not significant in CAL and PPD (p > 0.5) and significant in the participants percentages of salivary pH values (p Conclusion: The e-cigs smoking habit was the cause of an increase in periodontal disease severity among the electronic smokers rather than passive e-cigs smokers, although the salivary pH was higher in the latter.

Development of a new Cox model for predicting long-term survival in hepatitis cirrhosis patients underwent transjugular intrahepatic portosystemic shunts

BACKGROUND Transjugular intrahepatic portosystemic shunt(TIPS)placement is a procedure that can effectively treat complications of portal hypertension,such as variceal bleeding and refractory ascites.However,there have been no specific studies on predicting long-term survival after TIPS placement.AIM To establish a model to predict long-term survival in patients with hepatitis cirrhosis after TIPS.METHODS A retrospective analysis was conducted on a cohort of 224 patients who un-derwent TIPS implantation.Through univariate and multivariate Cox regression analyses,various factors were examined for their ability to predict survival at 6 years after TIPS.Consequently,a composite score was formulated,encompassing the indication,shunt reasonability,portal venous pressure gradient(PPG)after TIPS,percentage decrease in portal venous pressure(PVP),indocyanine green retention rate at 15 min(ICGR15)and total bilirubin(Tbil)level.Furthermore,the performance of the newly developed Cox(NDC)model was evaluated in an in-ternal validation cohort and compared with that of a series of existing models.RESULTS The indication(variceal bleeding or ascites),shunt reasonability(reasonable or unreasonable),ICGR15,post-operative PPG,percentage of PVP decrease and Tbil were found to be independent factors affecting long-term survival after TIPS placement.The NDC model incorporated these parameters and successfully identified patients at high risk,exhibiting a notably elevated mortality rate following the TIPS procedure,as observed in both the training and validation cohorts.Additionally,in terms of predicting the long-term survival rate,the performance of the NDC model was significantly better than that of the other four models[Child-Pugh,model for end-stage liver disease(MELD),MELD-sodium and the Freiburg index of post-TIPS survival].CONCLUSION The NDC model can accurately predict long-term survival after the TIPS procedure in patients with hepatitis cirrhosis,help identify high-risk patients and guide follow-up management after TIPS implantation.

Long-term outcomes after endoscopic removal of malignant colorectal polyps:Results from a 10-year cohort

BACKGROUND Choosing an optimal post-polypectomy management strategy of malignant colorectal polyps is challenging,and evidence regarding a surveillance-only strategy is limited.AIM To evaluate long-term outcomes after endoscopic removal of malignant colorectal polyps.METHODS A single-center retrospective cohort study was conducted to evaluate outcomes after endoscopic removal of malignant colorectal polyps between 2010 and 2020.Residual disease rate and nodal metastases after secondary surgery and local and distant recurrence rate for those with at least 1 year of follow-up were invest-igated.Event rates for categorical variables and means for continuous variables with 95%confidence intervals were calculated,and Fisher’s exact test and Mann-Whitney test were performed.Potential risk factors of adverse outcomes were RESULTS In total,135 lesions(mean size:22.1 mm;location:42%rectal)from 129 patients(mean age:67.7 years;56%male)were enrolled.The proportion of pedunculated and non-pedunculated lesions was similar,with en bloc resection in 82%and 47%of lesions,respectively.Tumor differentiation,distance from resection margins,depth of submucosal invasion,lymphovascular invasion,and budding were reported at 89.6%,45.2%,58.5%,31.9%,and 25.2%,respectively.Residual tumor was found in 10 patients,and nodal metastasis was found in 4 of 41 patients who underwent secondary surgical resection.Univariate analysis identified piecemeal resection as a risk factor for residual malignancy(odds ratio:1.74;P=0.042).At least 1 year of follow-up was available for 117 lesions from 111 patients(mean follow-up period:5.59 years).Overall,54%,30%,30%,11%,and 16%of patients presented at the 1-year,3-year,5-year,7-year,and 9-10-year surveillance examinations.Adverse outcomes occurred in 9.0%(local recurrence and dissemination in 4 patients and 9 patients,respectively),with no difference between patients undergoing secondary surgery and surveillance only.CONCLUSION Reporting of histological features and adherence to surveillance colonoscopy needs improvement.Long-term adverse outcome rates might be higher than previously reported,irrespective of whether secondary surgery was performed.

Does Smoking Weaken the Immune System: A Narrative Review

Smoking has a complex impact on the immune system, affecting both innate and adaptive immunity. It can exacerbate pathogenic immune responses and attenuate defensive immunity, leading to a higher susceptibility to infections and certain diseases. The chemicals in cigarette smoke, such as nicotine and carbon monoxide, can alter immune cell functions and inflammatory responses. Smoking can also have long-term effects on the immune system, with some changes persisting even after quitting [1]. According to a Penn Medicine Physician, the Medical Oncologist Dr. David Porter, “People who are smokers tend to get sicker from infections”, “It may be that smoking impacts the immune system’s ability to respond appropriately”. Thus, such individuals within smoking exposure history might be considered as immunocompromised due to the altered and weakened immune system. Cigarette smoking is a prevalent habit with far-reaching health implications. Among its many adverse effects, smoking significantly alters the immune system’s functionality [1].

Inhibition of the NF-κB Signaling Pathway Improves Cigarette Mainstream Smoke-Induced Lung Injury and Gut Microbiota Disturbance

Currently,cigarette smoke(CS)remains a major contributor to disease morbidity and mortality.CS can be divided into cigarette mainstream smoke(CMS)and side-stream smoke,depending on where it is produced by burning tobacco^([1]).CMS is inhaled by smokers from the filter end during cigarette combustion and is strongly associated with the development of several diseases^([2-4]).

Exploring the Impact of Alcohol Consumption and Smoking on Primary Open Angle Glaucoma: A Mendelian Randomization Study

Objective: Utilizing Mendelian Randomization, this study employs Single Nucleotide Polymorphisms (SNPs) as instrumental variables to explore the causal relationships between bibulosity, smoking, and Primary Open Angle Glaucoma (POAG). Methods: GWAS data for bibulosity, smoking, and POAG were obtained from the Social Science Genetic Association Consortium website and the IEU OpenGWAS Project website, respectively. Using a P-value threshold of −8, a linkage disequilibrium coefficient (r2) of 0.001, and a linkage disequilibrium region width of 10,000 kb, the data were aggregated, resulting in 6 SNPs for bibulosity and 253 SNPs for smoking. Three regression models, MR-Egger, Weighted Median Estimator (WME), and Random-Effects Inverse-Variance Weighted (IVW) were applied to analyze the causal impact of bibulosity and smoking on POAG. Results: The GWAS data for alcohol consumption and smoking were derived from European populations, while the GWAS data for Primary Open-Angle Glaucoma (POAG) were sourced from East Asian populations, with no gender restrictions. Analysis using three different regression models revealed that neither excessive alcohol consumption nor smoking significantly increased the risk of developing POAG. Specifically, the odds ratios with 95% confidence intervals for the alcohol consumption group were 0.854 (0.597 - 1.221) in MR-Egger regression, 0.922 (0.691 - 1.231) in WME regression, and 0.944 (0.711 - 1.252) in IVW regression. For the smoking group, the odds ratios were 1.146 (0.546 - 2.406) in MR-Egger regression, 0.850 (0.653 - 1.111) in WME regression, and 0.939 (0.780 - 1.131) in IVW regression. Given the significant heterogeneity in the SNPs associated with smoking, the focus was primarily on the results from the IVW regression model. Conclusion: Alcohol consumption and smoking are not significant risk factors for the development of POAG.

Physical, Mental and Social Wellbeing and Quality of Life among Current Smokers

Cigarette smoking has known negative effects on physical and mental health. Over 16 million Americans suffer from smoking-related illnesses, and one-third of individuals with mental health issues are also cigarette smokers. Both physical and mental health are associated with measures of overall quality of life, a critical outcome that can influence treatment, intervention, and prevention decision-making. However, the direct relation between smoking and quality of life is not clear and requires further investigation. The present study utilized data from 34,309 adults who participated in Wave 5 of the Population Assessment of Tobacco and Health (PATH) to examine the relation between smoking and quality of life while considering the mediating effects of physical and mental health, and the moderating effect of social satisfaction. Using Conditional Process Analyses to integrate mediation and moderation approaches, the present study found that smoking had indirect associations with quality of life mediated through both physical and mental health and that social satisfaction moderated these relationships. Additionally, smoking had an independent direct effect on quality of life that was not moderated by social satisfaction. Results suggest the negative impacts associated with smoking reach beyond its effect on physical, social and mental well-being.

Determinants of intentions to quit smoking among adult smokers in Bangladesh:findings from the International Tobacco Control(ITC)Bangladesh wave 2 survey

Background:With about 22 million adult smokers,Bangladesh needs strong measures that would promote smoking cessation.Using data from Wave 2 of the International Tobacco Control(ITC)Survey,this study examined the factors associated with intention to quit smoking among Bangladeshi smokers.Methods:Data from Wave 2 of the International Tobacco Control(ITC)Survey in Bangladesh,a face to face survey of adult smokers,were analysed.In the ITC survey,households were sampled using a stratified multistage design and interviewed using a structured questionnaire.Results:Of the respondents(N=2982),most were male(96%),married(80%),and Muslim(83%);33%were illiterate and 54%were aged below 40.Almost two-thirds were from areas outside Dhaka,78%smoked cigarettes exclusively;and 36%had an intention to quit smoking in the future.This study identified several predictors,comparable to other international studies,of intention to quit smoking:area of residence,number of cigarettes smoked daily,previous quit attempt,visiting a doctor in the past,having child aged 5 or below at home,perceived benefit from quitting,being worried about own health,knowledge of SHS,not enjoying smoking and workplace smoking policy.Conclusions:These findings suggest that the prevalence of intention to quit smoking is lower among Bangladeshi smokers than those among smokers in developed countries.However,the factors relating to quit intentions among Bangladeshi smokers are comparable to those found in Western countries.Population based tobacco control programs and policies should consider these predictors in the design of interventions to increase quitting among smokers in Bangladesh.

Small-scale fire tests in the underwater tunnel section model with new sidewall smoke extraction

The Shenzhen–Zhongshan Bridge is a 24‐km‐long bridge and tunnel system,including a 6.8-km-long super cross section subsea tunnel.To solve the smoke exhaust problem of a super large cross-section subsea tunnel,the tunnel has a new smoke exhaust system that combines a horizontal smoke exhaust cross section at the top and sidewall smoke exhaust holes.In order to evaluate the potential fire hazards of this type of tunnel,a 1:30 tunnel model was established and 140 smallscale experiments on underwater tunnel fires were conducted.By changing the fire power,fire location,and fan operation mode,different scenarios of submarine immersed tunnel fire were simulated and the related key parameters such as fire smoke diffusion behavior and smoke temperature distribution were studied.On this basis,the optimal smoke control strategy was proposed for different fire scenarios.The research results indicate that the new smoke exhaust system can fully utilize the smoke flow characteristics,significantly improve smoke exhaust efficiency,and increase available evacuation time,thus further enhancing the fire safety of super large cross-section subsea tunnels.

Tailoring Iron-Ion Release of Cellulose-Based Aerogel-Coated Iron Foam for Long-Term High-Power Microbial Fuel Cells

The presence of iron(Fe) has been found to favor power generation in microbial fuel cells(MFCs). To achieve long-term power production in MFCs, it is crucial to effectively tailor the release of Fe ions over extended operating periods. In this study, we developed a composite anode(A/IF) by coating iron foam with cellulose-based aerogel. The concentration of Fe ions in the anode solution of A/IF anode reaches 0.280 μg/mL(Fe^(2+) vs. Fe^(3+) = 61%:39%) after 720 h of aseptic primary cell operation. This value was significantly higher than that(0.198 μg/mL, Fe^(2+) vs. Fe^(3+) = 92%:8%) on uncoated iron foam(IF), indicating a continuous release of Fe ions over long-term operation. Notably, the resulting MFCs hybrid cell exhibited a 23% reduction in Fe ion concentration(compared to a 47% reduction for the IF anode) during the sixth testing cycle(600-720 h). It achieved a high-power density of 301 ± 55 mW/m^(2) at 720 h, which was 2.62 times higher than that of the IF anode during the same period. Furthermore, a sedimentary microbial fuel cell(SMFCs) was constructed in a marine environment, and the A/IF anode demonstrated a power density of 103 ± 3 mW/m^(2) at 3240 h, representing a 75% improvement over the IF anode. These findings elucidate the significant enhancement in long-term power production performance of MFCs achieved through effective tailoring of Fe ions release during operation.

Study on the Influence of Setting Parameters of Tunnel Centralized Smoke Extraction System on Fire Smoke Flow and Temperature Decay

The centralized smoke exhaust system of shield tunnel is an important determinant for tunnel fire safety,and the use of different design parameters of the tunnel smoke exhaust system will affect the smoke exhaust effect in the tunnel,and the influence of different design parameters on the smoke exhaust effect and temperature attenuation of the tunnel can help engineers in designing a more effective centralized smoke exhaust system for the tunnel.In this paper,the Fire Dynamic Simulator(FDS)is utilized to examine smoke exhaust vent settings for a centralized exhaust system in shield tunnel with both flat and sloped conditions,including slopes of+4.5%and−4.5%,under a 30MWfire power with a 150m^(3)/s smoke exhaust rate.The results suggest that maintaining a vent spacing of 60m and a vent size of 4.0 m×1.5 m is a reasonable configuration for centralized smoke exhaust systems in both flat and slope shield tunnels.This choice helpsminimize construction costs and prevent excessive smoke accumulation.It also promotes favorable conditions for maintaining temperature distribution at 2-m height,visibility,smoke spread distance,and temperature below the ceiling,all below the threshold values,while ensuring high smoke extraction efficiency.However,in the slope section,the chimney effect can disrupt exhaust efficiency,visibility,ceiling temperature,and temperature distribution at a height of 2 m.Employing different opening methods,such as having 2 vents up and 4 vents down in a+4.5%slope and 4 vents up and 2 vents down in a−4.5%slope,can help mitigate these effects.Furthermore,the temperature decay formula for shield tunnels follows a bi-exponential decay pattern,and different design parameters of centralized smoke exhaust systems have minimal effects on temperature decay in shield tunnels.