Abstract The study examines the development and application of microclimate standards for primary and secondary school classrooms, so as to ensure and promote the healthy growth of primary and secondary school students. The paper systematically reviews relevant domestic and international standards, analyzes the problems and shortcomings arising from their practical application and proposes effective countermeasures, in order to provide robust references aimed at optimizing the classroom environment in primary and secondary schools for student health, as well as offering practical support to advance the construction of a healthy China.

Objective: To understand the microclimate in primary and secondary school classrooms for the study period during the winter heating season, so as to provide a reference for the revision and improvement of relevant health standards. Methods: In December 2024, stratified random sampling was used to select 30 primary and secondary schools and 180 classrooms from the northern regions with centralized heating (Liaoning Province, Tianjin City) and the southern regions without centralized heating (Shanghai City, Anhui Province, and Jiangxi Province). Indoor temperature, relative humidity, wind speed, CO 2 and other indicators were measured on site. Variance analysis, t-test, Mann-Whitney U test and Kruskal-Wallis H test were used to analyze the differences in the microclimate of classrooms among regions and urban and rural differences. Results: The average temperature in the middle of the classrooms tested on site was (16.47±4.72)℃, and the variance analysis showed that the difference between the regions was statistically significant ( F=27.80, P <0.01). Among them, Tianjin had the highest average temperature of (20.43± 2.12 )℃, followed by Liaoning (19.03±2.23)℃, Shanghai (15.33±5.32)℃, Anhui (12.79±1.74)℃, and Jiangxi (11.69± 1.68 )℃. Horizontal temperature difference was 0.90 (0.50, 1.60)℃, the vertical temperature difference was 0.20 (0.10,0.60)℃, the average relative humidity was (44.39±16.16)%, the wind speed was 0.03(0.01,0.11)m/s, and the differences among different provinces and cities were statistically significant ( H/F =40.62, 82.69, 95.06, 55.28, all P <0.01). The average CO 2 volume concentration in urban areas of Tianjin, Liaoning, and Shanghai was 0.21(0.16,0.30)%, and there was no statistically significant difference ( H=4.65, P =0.10). There were grade differences in relative humidity ( F =3.71, 6.21) and CO 2 ( H =14.72, 12.92) in the north and the south (all P <0.05). In addition, the temperature, relative humidity, wind speed and CO 2 in the middle of the classroom were 42.8%, 67.8%, 100.0% and 22.2% respectively. Conclusions The temperature in the middle of the classroom in the non centralized heating area is lower than the standard, the relative humidity of classroom in the centralized heating area is lower than the standard，and the CO 2 in the classroom in winter is lower than the standard. It is recommended to install heating facilities in schools with low temperatures to increase the temperature and increase the frequency of ventilation in classrooms or adopt mechanical ventilation strategies to reduce CO 2 volume concentration.

Objective: To evaluate the classroom environmental management and CO 2 volume concentration in primary and secondary schools from Liaoning, Tianjin, and Shanghai, thereby providing a scientific basis for developing targeted strategies to improve classroom air quality. Methods: From December 16 to 26, 2024, by using stratified random cluster sampling method, the questionnaire survey was conducted in 72 primary and secondary schools (24 each of primary, junior high, and regular high schools) across Liaoning, Tianjin and Shanghai. Information on heating, ventilation and other classroom environmental management was collected. Additionally, 108 classrooms were selected for on site microclimate measurements, including temperature, humidity, wind speed and CO 2 volume concentration. Univariate analysis and multiple linear regression models were employed to explore related factors of classroom CO 2 volume concentration. Results: Among the three provinces/municipalities, 20.8% of schools regularly monitored the microclimate. The overall compliance rate for classroom CO 2 volume concentration was 17.6%. Multiple linear regression analysis showed that CO 2 volume concentration in regular and junior high school classrooms were higher than in primary school classrooms ( β=0.067, 0.046, 95%CI =0.036-0.099, 0.013-0.080); classrooms ventilated regularly in the morning and afternoon had higher CO 2 volume concentration than those ventilated during every break between classes ( β=0.043, 95%CI = 0.007- 0.080); both temperature ( β=0.010, 95%CI =0.004-0.016) and humidity ( β=0.003, 95%CI =0.002-0.004) were positively correlated with CO 2 volume concentration (all P <0.05). Conclusions Excessive CO 2 volume concentration in primary and secondary school classrooms is a prominent issue, and ventilation frequency is a key intervenable factor for controlling CO 2 levels. It is recommended to promote ventilation during every break between classes as a core management measure and to emphasize air quality supervision in regular high school classrooms.

Objective: To evaluate the current situation of thermal environment in primary and secondary school classrooms during winter, and to analyze students thermal comfort needs, so as to provide a basis for improving classroom thermal environment. Methods: From December 16 to 26, 2024, a stratified cluster random sampling method was used to select 90 classrooms from 15 primary and secondary schools in centralized/air conditioned heating areas(Liaoning Province, Tianjin City, Shanghai City) and naturally ventilated areas(Anhui Province and Jiangxi Province)for on site environmental measurement. A questionnaire survey was conducted among 743 students. The differences between groups using the χ 2 test were compared. Based on actual measurement data, a predicted mean vote prepared percentage of dissatisfied (PMV-PPD) model for centralized/air conditioned classrooms and an adaptive model for naturally ventilated classrooms were established, and the thermal neutral temperature and comfort interval were calculated. Results: The average outdoor temperature during on site measurement was 4.00(0.20，7.00)℃. In classrooms with centralized or air conditioned heating systems, the measured average temperature was (19.33±2.59)℃, with a thermal comfort range of 20.35-25.35 ℃ and a thermal neutral temperature of 22.85 ℃. And 13.92% of students reported feeling cold, while 80.80% felt comfortable. In classrooms with natural ventilation, the measured average temperature was (12.26±1.83)℃, with a thermal neutral temperature of 19.67 ℃ and a thermal comfort range of 16.17-23.17 ℃. About 48.33% of students reported feeling cold, and 49.81 % felt comfortable.The results of univariate analysis showed that there were statistically significant differences in shoe thickness, temperature sensation, relative humidity sensation and wind speed sensation between centralized/air conditioned heating areas ( χ 2= 7.01 , 31.47, 13.57, 13.80,all P <0.05). There were also statistically significant differences in school stage for primary and secondary school students, body mass index, classroom location for seat, temperature sensation, relative humidity sensation and wind speed sensation between naturally ventilated areas ( χ 2=42.13, 11.13, 11.04, 60.39, 29.27, 38.46,all P <0.05). Conclusions There are differences in thermal environment and students subjective thermal comfort in primary and secondary schools under different ventilation modes in winter. The temperature standards for heated classrooms should be revised, and differentiated environmental regulation strategies should be adopted based on different ventilation methods to improve students health and comfort levels.

Objective To systematically evaluate the radiation impact of radioactive sources used in online elemental analyzers in cement enterprises on the surrounding environment, and to provide a scientific basis for radiation monitoring and safety management at the application sites of this type of radioactive sources. Methods A statistical analysis was conducted on 15 cement enterprises in Guangxi Province using online elemental analyzers with ²⁵²Cf as the radioactive source. On-site investigation of radiation safety management and on-site monitoring of radiation environment were performed, followed by an evaluation based on the collected data. Results Although the gamma radiation ambient dose equivalent rate and neutron ambient dose equivalent rate increased around the sites using online elemental analyzers with ²⁵²Cf as the radioactive source, they all met the requirements of the Radiological Health Protection Requirements for Instruments with Sealed Sources (GBZ 125—2009). Conclusion Under the current usage and management conditions, the application of this type of radioactive sources has controllable radiation impact on the surrounding environment, and will not pose a threat to public health and environmental safety. However, continuous strengthening of radiation safety management measures and regular radiation monitoring work are still needed to ensure the safe use of radioactive sources, further reducing potential radiation risks and providing strong guarantees for the safe application of radioactive sources in online elemental analyzers in cement enterprises.

Objective To provide technical support for the formulation of scientific and reasonable supervision measures for enterprises engaged in the exploitation and utilization of ores with associated radionuclides in Guangxi Province, China. Methods A radionuclide analysis was performed on solid materials generated during production processes such as zirconium-titanium ore dressing and processing in multiple enterprises in Guangxi Province. The radiation levels of effluents was measured. Measurement and analysis were performed on the environmental air radon concentration levels and environmental γ-radiation dose rates at the factory boundaries of these enterprises and the surrounding environmental protection targets. Results The air absorption dose rate of γ radiation, the concentrations of radon and its daughters, and the radiation levels of surface water and aerosols at the factory boundaries and in the surrounding environment were all at normal levels. The specific activities of nuclides ²³⁸U, ²³²Th, and ²²⁶Ra in the raw ore, zirconium products, rutile products, and monazite products within the factory area were relatively high. The γ radiation air absorption dose rates in the corresponding workshops were also relatively high, with the zirconium-rutile workshop being the area with the highest values. Materials such as zirconium products, rutile, and monazite all showed a certain amount of radon exhalation. Conclusion The radiation level of tailings met the criteria of monitoring exemption, and the enterprises did not generate radioactive solid waste. Attention should be paid to the personal dose of the staff in areas with high radiation dose rates.

The investigation of environmental radioactivity level is an important basic work of ecological environment protection. It can provide basic data and scientific basis for the evaluation of radioactive environment quality and the formulation of radiation safety regulations and standards. Based on many years of practical experience of environmental radioactivity level investigation, combined with relevant regulations and standards, this paper summarizes the common investigation methods in the investigation and research of environmental radioactivity level at home and abroad, summarizes a set of environmental radioactivity level investigation scheme with strong applicability, and gives detailed suggestions on the ideas, methods, technical routes and other key points of the investigation scheme. The research results of this paper can provide a reference for the preparation of environmental radioactive level investigation scheme.

Objective The radioactivity level survey was carried out in Weizhou Island area of Beihai, to comprehensively master the radiation environment status in the area, understand the natural radioactivity level and its distribution law, and provide basic data for scientific evaluation of radiation environment quality. Methods According to the relevant standards and technical specifications, the air absorbed dose rate of gamma radiation in Weizhou Island area was monitored from April 2020 to March 2021, the concentrations of radionuclides in water, soil and other environmental samples were sampled and analyzed, and the monitoring results were analyzed and discussed in combination with the regional characteristics. Results The results show that the air absorbed dose rate of gamma radiation in Weizhou Island area ranges from 0.2～122 nGy/h; the activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs in solid samples range 17.0～37.3 Bq/kg, < 0.501～29.5 Bq/kg, < 0.766～54.3 Bq/kg, 18.7～369 Bq/kg and < 0.212～1.48 Bq/kg, respectively, the concentrations of U and Th in well water and reservoir water range 0.065～0.25 μg/L, 0.046～0.079 μg/L, the activities of ²²⁶Ra, ⁴⁰K, total α and total β range 1.42～3.08 mBq/L, 0.069～0.231 Bq/L, 0.025～0.163 Bq/L, 0.082～0.572 Bq/L, respectively, the concentrations of U and Th in seawater samples range 1.81～2.25 μg/L, 0.634～0.648 μg/L, and the activities of ²²⁶Ra, ⁴⁰K, ⁹⁰Sr and ¹³⁷Cs range 9.38～19.7 mBq/L, 11.3～11.8 Bq/L、0.193～0.866 mBq/L、1.13～1.42 mBq/L. Conclusion The environmental ionizing radiation level in Weizhou island of Beihai is in the range of background fluctuation and at a relatively low level, indicating that the radiation environmental quality of Weizhou Island and its surrounding areas is good.

Objective:To explore the action mechanism of suppressing expression of mitogen- activated protein kinase 14（MAPK14）to alleviate glutamate excitatory toxicity and its neuronal protection effect.Methods:Lentivirus-mediated MAPK14 interference vector was synthetized by Shanghai Jikai Gene Chemical Technology Co.，Ltd. Astrocytes were obtained from SD rats 48 hours after birth，which were cultured in vitro and transfected by lentivirus-mediated transfection. According to the random number table，the cells were divided into three groups：（1）un-transfected group（normal group）with normal astrocytes and the cells were cultured in regular medium composed of Dulbecco's?modified Eagle's?medium（DMEM）；（2）negative control group with astrocytes transfected by MAPK14 no-loaded interference vector；（3）lentivirus transfected group with astrocytes transfected by MAPK14 interference vector. Seventy-two hours after transfection，astrocytes were co-cultured with neurons for 48 hours，and then they were cultured in a medium containing glutamate for 2 hours. The detection indexes included the optimal multiplicity of infection（MOI）value for astrocytes transfected by lentivirus vector，mRNA levels of MAPK14 and glial glutamate transporter 1（GLT-1）detected by rPCR 72 hours after transfection，protein levels of MAPK14 and GLT-1 detected by Western blot 72 hours after transfection，level of lactate dehydrogenase（LDH）and mortality of neurons measured by spectrophotometry and flow cytometry 2 hours after culturing in the medium with glutamate. Results:（1）The optimal MOI value for lentivirus transfecting astrocytes was 30，and astrocytes grew well after transfection.（2）Seventy-two after transfection，the mRNA level of MAPK14 in lentivirus transfected group（0.005 7±0.000 6）was significantly decreased as compared with un-transfected group（0.013 1±0.001 1）and negative control group（0.013 9±0.001 0）（ P<0.01），the mRNA level of GLT-1 in lentivirus transfected group（0.009 1±0.001 2）was not significantly changed as compared with un-transfected group（0.008 7±0.000 3）and negative control group（0.008 9±0.001 1）（ P>0.05）.（3）Seventy-two hours after transfection，the protein level of MAPK14 in lentivirus transfected group（0.29±0.04）was significantly decreased as compared with non-transfected group（0.61±0.05）and negative control group（0.63±0.01）（ P<0.01），the protein level of GLT-1 in lentivirus transfected group（0.73±0.06）was significantly increased as compared with un-transfected group（0.20±0.03）and negative control group（0.23±0.09）（ P<0.01）.（4）After astrocytes were co-cultured with neurons and subsequently cultured in the medium containing glutamate for 2 hours，the level of LDH in lentivirus transfected group［（109.67±2.40）U/L］was significantly lower than that in un-transfected group［（141.52±3.88）U/L］and negative control group［（141.29±3.61）U/L］（ P<0.01）. The mortality of neurons in lentivirus transfected group［（38.72±0.26）%］was significantly lower than that in un-transfected group［（52.94±1.36）%］and negative control group［（54.30±1.23）%］（ P<0.01）. Conclusions:The transfection with lentivirus-mediated MAPK14 interference vector can increase expression of GLT-1 in astrocytes to increase glutamate re-uptake and relieve the glutamate excitatory toxicity in neurons，which may provide a new experimental basis for future use of astrocyte gene regulation to alleviate neuronal injury caused by glutamate excitatory toxicity after traumatic brain injury.

By increasing the release of Ca2+ from sarcoplasmic reticulum in cardiomyocytes,salidroside elevates myocardial contraction,and by up-regulation of sarcoplasmic reticulum Ca2+-ATPase expression,and down-regulation ofcalcineurin expression to promote Ca2+ return to sarcoplasmic reticulum,salidroside obstructs Ca2+ overload-induced myocardial injury,and improves heart function.Salidroside inhibits lipid peroxidation,and increases activities of enzymatic antioxidants in heart tissue,and inhibits expression of inflammatory cytokines,and mitochondrial permeability transition pore opening,thus blocks myocardial apoptosis,by anti-oxidation and anti-inflammation;salidroside improves myocardial ischemia by up-regulation of hypoxia-inducible factor and vascular endothelial growth factor expression to promote angiogenesis in ischemic myocardium;salidroside improves respiratory function of mitochondria in myocardium by stimulating PGC-1 αt-NRF-1/NRF-2 signaling pathway to produce finally cardioprotective effect.These effects of salidroside are thought that are major mechanism of antagonizing cardiac injury induced by hypoxia,ischemia,ischemic-reperfusion,exhaustive exercise,chemicals,and biologic toxin.