Background Polycyclic aromatic hydrocarbons (PAHs) are significant organic components of PM_2.5 and exhibit carcinogenic and mutagenic properties. Long-term exposure to high level of atmospheric particulate matter and particle-bound PAHs may contribute to the burden of environmentally related diseases in China. Objective To characterize PM_2.5 concentrations and PM_2.5-bound PAHs in three districts of Guangzhou from 2016 to 2024, and to assess the incremental lifetime cancer risk (ILCR) associated with inhalation exposure to PAHs among different population groups. Methods PM_2.5 samples were collected monthly from the 10th to the 16th day of each month at rooftop monitoring sites on office buildings in Yuexiu, Conghua, and Panyu districts between 2016 and 2024. PM_2.5 concentrations were measured, and 16 priority PAHs were quantified using high-performance liquid chromatography (HPLC). Seasonal and regional variations in PM_2.5 and PAH concentrations were analyzed using the Kruskal-Wallis test. Potential PAH sources were identified using diagnostic ratio analysis and principal component analysis (PCA). The ILCR model was employed to estimate inhalation-related cancer risks for different population groups. Results From 2016 to 2024, the annual median PM_2.5 concentrations in Guangzhou were 51.0, 46.0, 45.0, 41.5, 31.0, 32.0, 30.0, 26.0, and 37.5 μg·m⁻³, respectively, showing an overall declining trend. PM_2.5 concentrations varied significantly by season, following the order of winter > spring/autumn > summer (H=475.341, P < 0.001). Spatially, PM_2.5 concentrations were highest in Yuexiu, followed by Panyu and Conghua (H=36.226, P < 0.001). The annual median PAH concentrations were 3.95, 4.22, 3.73, 3.13, 2.54, 2.16, 2.78, 2.36, and 1.75 ng·m⁻³, respectively. PAH concentrations showed a similar seasonal pattern (winter > spring/autumn > summer; H=320.392, P < 0.001). However, their spatial distribution differed from that of PM_2.5: Conghua > Panyu > Yuexiu (H=55.938, P < 0.001). Diagnostic ratios and PCA indicated that the major sources of PAHs were traffic-related emissions (gasoline and diesel combustion) and coal combustion, with additional contributions from petroleum volatilization and biomass burning. Benzo[a]pyrene (BaP) toxic equivalent concentrations declined over time and remained below the Chinese standard limit of 1 ng·m⁻³ after 2018. The median inhalation-related ILCRs were 0.094×10⁻⁶ for children, 0.035×10⁻⁶ for adolescents, and 0.293×10⁻⁶ for adults. Conclusion From 2016 to 2024, PM_2.5 and PM_2.5-bound PAH pollution levels in Guangzhou generally declined. Suburban areas had the lowest PM_2.5 concentrations but the highest PAHs concentrations. Both PM_2.5 and PM_2.5-bound PAHs exhibited significant seasonal variations, with the highest levels in winter and the lowest levels in summer. The primary sources of PAHs were vehicular emissions and coal combustion, and PAHs posed no significant carcinogenic risk to the study population.

Objective To quantitatively assess the association of short-term exposure to polycyclic aromatic hydrocarbons (PAHs) in ambient fine particulate matter (PM2.5) with residents mortality. Methods A time-stratified case-crossover study was conducted from 2020 to 2022 among 10606 non-accidental residents by using the Guangzhou Cause of Death Surveillance System in Conghua District, Guangzhou. Exposure levels of PAHs in PM_2.5 and meteorological data during the study period were obtained from the Center for Disease Control and Prevention in Conghua District and the China Meteorological Administration Land Data Assimilation System (CLDAS-V2.0), respectively. Conditional Poisson regression model was used to estimate the exposure-response association between PAHs and the mortality risk. Results Fluoranthene, chrysene, benzo[k]fluoranthene, benzo[a]pyrene, and indeno[1,2,3-cd]pyrene were significantly associated with an increased risk of mortality. For every one interquartile range increase in exposure levels, the non-accidental mortality risks increased by 8.33% (95% CI: 1.80%, 15.27%), 4.67% (95% CI: 1.86%, 7.57%), 6.07% (95% CI: 2.08%, 10.21%), 4.62% (95% CI: 1.85%, 7.47%), and 4.70% (95% CI: 0.53%, 9.03%), respectively. The estimated non accidental deaths attributable to exposure to fluoranthene, chrysene, benzo[k]fluorine, benzo[a]pyrene and indine[1,2,3-cd]pyrene were 5.91%, 6.08%, 6.51%, 6.46%, and 4.21%, respectively. Conclusions Short-term exposure to PAHs in PM_2.5, including fluoranthene, chrysene, benzo[k]fluoranthene, benzo[a]pyrene and indine[1,2,3-cd]pyrene, was significantly associated with an increased risk of mortality among residents.

We employ the SWOT (strengths, weaknesses, opportunities, and threats) method to conduct a comprehensive analysis on general dentist training in stomatological colleges. General dentistry possesses internal strengths including a good education environment, a well-established discipline system, and less competitive employment, but also faces internal weaknesses such as a lack of awareness of development and inadequate capacities of teaching staff and teaching bases. We delve into its external opportunities such as a great demand for general dental practitioners at primary institutions and national support policies, and discuss various challenges such as the low recognition and trust of general dentists at the grass-roots level and the weak attractiveness of such jobs. Based on these conclusions, we suggest strengthening discipline construction, improving teaching staff capacity building, perfecting textbooks and practice bases, and closely linking general dental education with the development of local health care, in order to provide a basis for advancing general dental medicine.

We employ the SWOT (strengths, weaknesses, opportunities, and threats) method to conduct a comprehensive analysis on general dentist training in stomatological colleges. General dentistry possesses internal strengths including a good education environment, a well-established discipline system, and less competitive employment, but also faces internal weaknesses such as a lack of awareness of development and inadequate capacities of teaching staff and teaching bases. We delve into its external opportunities such as a great demand for general dental practitioners at primary institutions and national support policies, and discuss various challenges such as the low recognition and trust of general dentists at the grass-roots level and the weak attractiveness of such jobs. Based on these conclusions, we suggest strengthening discipline construction, improving teaching staff capacity building, perfecting textbooks and practice bases, and closely linking general dental education with the development of local health care, in order to provide a basis for advancing general dental medicine.

We analysed the similarities between theory of The Inner Canon of Yellow Emperor （《黄帝内经》） and modern sleep medicine on sleep and wakefulness， and initially constructed the "eye-brain" sleep regulation system. The similarities between the sleep theories in The Inner Canon of Yellow Emperor and modern sleep medicine research are described from three perspectives： the anatomical basis of sleep physiology， the pathogenesis of sleep disorder pathology， and the mechanism of sleep disorder treatment. It is found that the regulation of sleep and wakefulness in both medicine theories is based on the "eye" and "brain" as the main control centres， and there exists a "eye-brain" pathway to regulate sleep and wakefulness in the human body. Based on this， the "eye-brain" sleep regulation theory is constructed， in order to find an effective way to solve the pathogenesis and treatment strategy of sleep disorders.

Objective:To investigate the application effect of case-based learning (CBL) based on the clinical case library of stomatology in standardized residency training for comprehensive stomatology.Methods:A total of 52 residents in Department of Stomatology, Chongqing Medical University, were given CBL teaching based on the clinical case library of comprehensive stomatology, and a questionnaire survey was performed to evaluate the teaching effect. Theoretical and skill assessments were performed before and after CBL teaching, and a comparative analysis was performed. SPSS 19.0 software was used for the t-test. Results:The questionnaire survey showed that CBL teaching based on the clinical case library of stomatology effectively improved the ability of independent learning [92.31% (48/52)], the interest in learning [88.46% (46/52)], and the ability for case diagnosis and the accuracy of investigation and judgment [94.23% (49/52)]. This method helped with the mastery and understanding of the theoretical knowledge in stomatology [96.15% (50/52)] and improved the abilities for expression and communication [84.62% (44/52)] and the ability to find and solve problems [94.23% (49/52)]. It also helped to stimulate the interest in scientific research and teaching [82.69% (43/52)] and create an active classroom atmosphere [82.69% (43/52)]. Among these residents, 94.23% (49/52) liked CBL teaching, and 88.64% (46/52) thought the setting of the case library was reasonable. After the application of CBL teaching, there were significant increases in theoretical score [from (66.74±4.25) points to (81.44±7.16) points] and skill examination score [from (64.00±3.14) points to (81.96±7.50) points].Conclusions:CBL teaching based on the case library of stomatology has a good teaching effect in the standardized residency training for comprehensive stomatology and can not only improve the theoretical and skill assessments of residents, but also improve their learning interest and clinical thinking ability.

Objective:Cardiac arrest (CA) represents a significant public health challenge, posing a substantial threat to individual health and survival. To enhance the survival rates of patients experiencing out-of-hospital cardiac arrest (OHCA), Baoan District in Shenzhen City has undertaken exploratory initiatives and practical interventions, yielding promising preliminary outcomes.Methods:1.Innovate emergency medical services by developing a "four-circle integration" system that connects to the hospital. This system encompasses the social emergency medical system, the out-of-hospital emergency medical system, the in-hospital emergency medical service system, and the intensive care treatment system. 2.Develop a comprehensive model for the construction of a social emergency medical training system, characterized by party leadership, government oversight, departmental coordination, professional guidance, technological support, and community involvement, termed the "Baonan Model." Additionally, establish evaluation criteria to assess the effectiveness of the social emergency medical training system in Baonan District; 3. Develop a cardiac arrest registration system and a social emergency medical training management system for Baonan District; 4. Enhance the proficiency in treatment techniques and the quality of cardiopulmonary resuscitation among emergency medical professionals; 5. Strengthen and advance the development of a "five-minute social rescue network" to address the critical "emergency window period." .Result:In Baonan District, 9.18% of the public is trained in emergency medical skills. The bystander CPR rate for OHCA is 26.11%, AED use is at 4.78%, the 30-day survival rate is 6.31%, and the discharge survival rate is 4.44%.Conclusion:The implementation of the aforementioned measures can substantially enhance the survival rate of patients experiencing OHCA at the time of discharge.

Objective:To explore the application effect of task-driven teaching method combined with Sandwich teaching method in the standardized residency training of oral general practitioners.Methods:A total of 40 trainees of the standardized residency training of the Teaching and Research Section of Oral General Practice in Chongqing Medical University were randomly divided into experimental group and control group. The experimental group ( n=20) adopted task-driven teaching method combined Sandwich teaching method, and the control group ( n=20) adopted the traditional teaching method. The theory assessment, skills assessment and the teaching satisfaction questionnaire survey were conducted to evaluate the teaching effects. SPSS 19.0 software was used for t-test. Results:The theoretical test scores of the experimental group were significantly higher than those of the control group [(85.85±25.61) points vs. (74.35±10.53) points], and the difference between the two groups was statistically significant ( t=8.56, P < 0.001). The skill test scores of the experimental group were significantly higher than those of the control group [(86.50±18.20) points vs. (73.40±16.57) points], and the difference was statistically significant ( t=9.94, P<0.001). The results of the teaching satisfaction questionnaire showed that the experimental group had significantly higher scores than control group in such seven aspects as improving students autonomous learning ability and interest in learning, teamwork and interpersonal relationships, diagnostic ability of cases and the accuracy, doctor-patient expression and communication ability, ability to find and solve problems, stimulating interest in scientific research and teaching, mastering and understanding the oral theoretical knowledge and so on ( t=10.40, 10.40, 9.95, 5.43, 7.66, 8.08, 9.60, respectively, all P<0.001). Task-driven teaching combined with Sandwich teaching method stimulated the learning interest of trainees and improved their comprehensive ability. Conclusion:Task-driven teaching combined with Sandwich teaching method has greatly improved the teaching effect of standardized residency training of oral general practitioners.

Objective:To explore the correlation between SAM domain and HD domain-containing protein 1 (SAMHD1) and programmed death-ligand 1 (PD-L1) expression in lung adenocarcinoma.Methods:The expression of SAMHD1 in lung adenocarcinoma and its effect on prognosis were analyzed by online database GEPIA and Kaplan-Meier Plotter. The expression of SAMHD1 in lung adenocarcinoma cell lines was detected by quantitative real-time PCR (qPCR) and Western blotting. SAMHD1 gene was silenced in H1975, H1299 and LLC cells by small interfering RNA transfection and lentivirus infection, respectively. The mRNA and protein expression levels of PD-L1 in lung adenocarcinoma cells of control group, siSAMHD1-1 group and siSAMHD1-2 group were detected by qPCR and Western blotting. The membrane PD-L1 level was detected by flow cytometry. A mouse lung adenocarcinoma xenograft model was constructed. The PD-L1 levels in the tumor tissues of control group and shSAMHD1 group were detected by immunohistochemistry. Cell proliferation activities of the control, siSAMHD1-1 and siSAMHD1-2 groups were detected by CCK-8 assays.Results:The GEPIA database results showed that the mRNA expression of SAMHD1 in lung adenocarcinoma was lower than that in normal lung tissue (4.81±0.90 vs. 5.99±0.76, t=20.67, P<0.001) . The median overall survival time of patients with high SAMHD1 expression was significantly longer than that of patients with low SAMHD1 expression (109.0 months vs. 87.7 months, χ2=26.83, P=0.002) . The relative mRNA expression levels of SAMHD1 in A549, PC9, H1299 and H1975 cells were 1.00±0.02, 0.75±0.05, 3.49±0.19 and 7.25±0.38 ( F=589.00, P<0.001) , and the relative protein expression levels were 1.00±0.06, 0.34±0.07, 1.67±0.22 and 2.11±0.63 ( F=15.79, P=0.001) . In H1975 cells, the relative mRNA levels of PD-L1 in the control, siSAMHD1-1 and siSAMHD1-2 groups were 1.00±0.00, 1.54±0.26 and 2.89±0.13 ( F=102.30, P<0.001) , and the relative protein expression levels were 1.00±0.01, 1.50±0.10 and 1.52±0.33 ( F=6.65, P=0.030) . In H1299 cells, the relative mRNA levels of PD-L1 in the three groups were 1.00±0.08, 1.63±0.03 and 2.14±0.03 ( F=368.80, P<0.001) , and the relative protein levels of PD-L1 were 1.00±0.07, 1.88±0.35 and 2.05±0.38 ( F=10.66, P=0.011) . The expression level of PD-L1 in the siSAMHD1-1 and siSAMHD1-2 groups was higher than that in the control group (all P<0.05) . Flow cytometry results showed that in H1975 cells, the fluorescence intensity of membrane PD-L1 in the control, siSAMHD1-1 and siSAMHD1-2 groups were 246.83±27.59, 325.60±8.00 and 308.93±7.60 ( F=17.56, P=0.003) , and in H1299 cells, the fluorescence intensity of membrane PD-L1 in the three groups were 959.00±6.25, 1 084.33±7.64 and 1 085.33±21.22 ( F=86.74, P<0.001) . The fluorescence intensity of PD-L1 in the siSAMHD1-1 group and siSAMHD1-2 group was higher than that in the control group (all P<0.05) . In xenograft mouse model, the H-SCORE of PD-L1 in the shSAMHD1 group was higher than that in the control group (7.99±1.10 vs. 4.49±0.43, t=5.13, P=0.007) . The proliferative activities of H1975 cells in the control group, siSAMHD1-1 group and siSAMHD1-2 group at 72 h were 0.50±0.02, 0.75±0.05 and 0.73±0.06 ( F=25.01, P=0.001) . The proliferative activities of H1299 cells in the three groups at 72 h were 0.80±0.01, 1.00±0.04 and 0.93±0.07 ( F=13.90, P=0.006) . The cell proliferation activity in the siSAMHD1-1 group and siSAMHD1-2 group was higher than that in the control group (all P<0.05) . Conclusion:SAMHD1 silencing induces PD-L1 expression in lung adenocarcinoma.

Objective: To explore the effect of RW splints on the position and occlusal relationship of classⅡ malocclusion patients with temporomandibular disorder (TMD) to provide a basis for the diagnosis and design of this kind of patient. Methods : Fifteen patients with class Ⅱ malocclusions with TMD were enrolled in this study. After 8 months of RW-splint treatment, the changes in jaw position (∠ANB, SN-MP, ∠S-G0/N-Me) and occlusal relationship (molar, cuspid teeth displacement and anterior overbite/overjet value) were recorded by a condylar displacement measuring instrument at the CR position and CO position. Results: After RW-splint treatment, the mean values of ∠ANB (t=4.971, P=0.001) and ∠SN-MP (t=9.895, P ＜ 0.01) were increased in all 15 patients, and the mean value of S-G0/N-Me (t=5.342, P=0.005) was decreased. The mean values of the distal movement of the first molars on the left and right sides of the mandible were (1.57 ± 0.79) mm and (1.69 ± 1.29) mm, respectively; the mean values of the distal movement of the canines on the left and right sides of the mandible were (1.54 ± 0.50) mm and (1.51 ± 1.08) mm, respectively; and the mean values of the overbite were (1.16 ± 0.60) mm and (1.99 ± 0.85) mm, respectively. Conclusion After RW-splint treatment, the jaw rotates clockwise, and the relationship between the molars and canines changes obviously in class Ⅱ patients with TMD, which provides a reference for the diagnosis and treatment plan of this kind of patient.