Objective: To investigate the prevalence and associated factors of depressive symptoms among junior and senior high school students in Beijing from 2019 to 2023, in order to provide a scientific basis for interventions targeting high risk groups. Methods: From 2019 to 2023, a stratified cluster random sampling method was used to select 88 927 junior and senior high school students from 16 districts in Beijing. The Center for Epidemiologic Studies Depression Scale(CES-D) was conducted to assess depressive symptoms. The Chi square test was used to compare the detection rates of depressive symptoms among different student groups, and the trend Chi square test was employed for trend analysis of detection rates across the years. Multivariate Logistic regression analysis was applied to examine the association between the detection of depressive symptoms and related factors among junior and senior high school students. Results: From 2019 to 2023, the prevalence rates of depressive symptoms among junior and senior high school students in Beijing were 20.45%, 18.19%, 16.64%, 17.89% and 18.17%, respectively, with an overall downward trend ( χ 2 trend =27.51, P <0.01). Multivariate Logistic regression analysis revealed that after adjusting for gender, monitoring year, educational stage,family structure,boarding status and has taken a medical leave of absence in the past year unhealthy dietary behaviors ( OR=1.80, 95%CI =1.73-1.87), physical inactivity ( OR=1.24, 95%CI =1.19-1.29), try smoking ( OR=1.46, 95%CI =1.35-1.58), try alcohol( OR=1.96, 95%CI =1.88-2.05), Internet addiction ( OR=3.88, 95%CI =3.57-4.22), and adverse ear related behavior ( OR=1.82, 95%CI =1.71-1.93) were all associated with an increased risk of depressive symptoms among junior and senior high school students (all P <0.05). Conclusions The prevalence depression symptoms among middle school students in Beijing showed a fluctuating downward trend from 2019 to 2023. Targeted interventions should be adopted to reduce the occurrence of depression symptoms among junior and senior high school students.

Objective: To understand the trends of classroom lighting and illumination of primary and secondary schools in Beijing from 2016 to 2023, so as to provide a scientific basis for targeted improvement measures. Methods: A sampling survey was conducted on the lighting and illumination indicators of 8 390 classrooms in primary and secondary schools in Beijing from 2016 to 2023. The survey included classroom daylight factor, window to floor area ratio, average illuminance and illuminance uniformity on the desks, average illuminance and illuminance uniformity on blackboards, as well as classroom lighting and blackboard illumination sources. Intergroup comparisons were performed using the Kruskal-Wallis H test and the Chi square test, and Spearman correlation analysis was used to examine the trend of classroom lighting and illumination changes. Results: Except the window to floor area ratio, the measured values and compliance rates of all lighting and illumination indicators showed an overall upward trend from 2016 to 2023 (daylight factor r = 0.27, χ 2 trend =206.80, average illuminance on the desk surface r =0.30, χ 2 trend =87.97, illuminance uniformity on the desk surface r =0.14, χ 2 trend =73.59, average illuminance on the blackboard r =0.33, χ 2 trend =477.43, illuminance uniformity on the blackboard r = 0.09, χ 2 trend =50.76) (all P ＜0.01). The lighting and illumination indicators of classrooms (included classroom daylight factor, average illuminance and illuminance uniformity on the desks, average illuminance and illuminance uniformity on blackboards) in urban schools, primary schools, and secondary schools from 2016 to 2023 showed an upward trend (urban r =0.23-0.40, χ 2 trend =88.66-392.18; primary school r =0.12-0.36, χ 2 trend =39.50-281.44; secondary schools r =0.06-0.31, χ 2 trend =11.79-213.73) (all P ＜ 0.01 ). The illuminance uniformity on the blackboard in suburban schools showed a downward trend ( r = -0.09, χ 2 trend =31.53, both P ＜0.01). The illuminance uniformity on the desk surface in suburban schools showed no significant change ( r =0.03, χ 2 trend =1.23, both P ＞0.05). The other indicators showed an upward trend (daylight factor r =0.28, χ 2 trend =40.69, average illuminance on the desk surface r =0.24, χ 2 trend =16.35, average illuminance on the blackboard r =0.25, χ 2 trend =118.05, all P ＜0.01). The trends of classroom and blackboard illumination sources were that fluorescent lamps decreased year by year and LED lamps increased by year (classroom illumination sources χ 2 trend =1 059.82, blackboard illumination sources χ 2 trend =1 070.25, both P ＜0.01). Conclusions The classroom lighting and illumination in primary and secondary schools in Beijing has shown an overall improving trend from 2016 to 2023. However, problems remain, such as limited improvement of illuminance uniformity indicators, late start and poor effect of reconstruction in suburban schools. Further improvements are still needed.

Objective: To investigate the iodine nutrition status of children aged 8-10 in Guangming, Longhua and Yantian District of Shenzhen in 2023, and to explore the influencing factors of thyroid volume. To evaluate prevention strategies and to provide a scientific basis for the elimination of iodine deficiency disorders. Methods: Urine and household salt samples were randomly collected from 580 non-boarding students aged 8-10 years foriodine content detection. Thyroid volume was measured using a fully digital ultrasound imaging system, and goiter prevalence was calculated. Results: A total of 580 samples was tested. The median salt iodine concentration was 23.86 mg/kg, with 93.62% qualified iodized salt and 94.48% coverage rate. The median of urinary iodine was 265.00 μg/L, mainly distributed between 200 - < 300 μg/L and ≥300 μg/L. The proportion of children with ap⁃ propriate iodine was 20. 86% , and the proportion of children with insufficient or excessive urinary iodine levels was 10. 86% and 68. 28% of the total surveyed population , respectively. The median thyroid volume was 3. 27 mL , and the goiter rate was 1. 72% . Multiple linear regression analysis showed that age was the risk factor for thyroid volume (8=0 328, P<0.05). while urinary iodine was the protective factor for thyroid volume(B=-4.134x10-4,P<0.05). Conclusion The qualified iodized salt rate, median of urinary iodine,and goiter prevalence of 580 children aged 8 - 10 meet the elimination criteria for iodine deficiency disorders. Age and urinary iodine are closely related to thyroid volume change. The urinary iodine level of children is generally high and requires serious attention.

ObjectiveTo explore the quantity-quality transfer process of medicinal materials， decoction pieces and standard decoction of Haliotidis Concha（Haliotis discus hannai） by analyzing the physical phase and compositional changes， so as to provide references for the effective control of its quality. MethodsA total of 20 batches of Haliotidis Concha（H. discus hannai） from different habitats were collected and prepared into corresponding calcined products and standard decoction， and the content of CaCO₃ of the three samples were determined and the extract yield and transfer rate of CaCO₃ were calculated. The changes in elemental composition and their relative contents were investigated by X-ray fluorescence spectrometry（XRF）， X-ray diffraction（XRD） was used to study the changes in the phase compositions of the three samples and to establish their respective XRD specific chromatogram. Fourier transform infrared spectrometry（FTIR） was used to study the changes in the chemical composition and content changes of the three samples and to establish their respective FTIR specific chromatogram， while combining hierarchical cluster analysis（HCA）， principal component analysis（PCA） and orthogonal partial least squares-discriminant analysis（OPLS-DA） to find the common and differential characteristics， in order to explore the quantity-quality transfer relationship in the preparation process of standard decoction of Haliotidis Concha（H. discus hannai）. ResultsThe CaCO₃ contents of the 20 batches of medicinal materials， decoction pieces and standard decoction of Haliotidis Concha（H. discus hannai） were 93.87%-98.95%， 96.02%-99.97% and 38.29%-51.96%， respectively， and the extract yield of standard decoction was 1.71%-2.37%， and the CaCO₃ transfer rate of decoction pieces-standard decoction was 0.68%-1.27%. XRF results showed that the elemental species and their relative contents contained in Haliotidis Concha and its calcined products had a high degree of similarity， and although there was no obvious difference in the elemental species contained in decoction pieces and standard decoction， the difference in the relative contents was obvious， which was mainly reflected in the decrease of the relative content of element Ca and the increase of the relative content of element Na. XRD results showed that Haliotidis Concha mainly contained CaCO₃ of aragonite and calcite， while calcined Haliotidis Concha only contained CaCO₃ of calcite， and standard decoction mainly contained CaCO₃ of calcite and Na₂CO₃ of natrite. FTIR results showed that there were internal vibrations of O-H， C-H， C=O， HCO₃^- and CO₃^2- groups in Haliotidis Concha， while O-H， HCO₃^- and CO₃^2- groups existed in the calcined products and standard decoction. ConclusionThe changes of Haliotidis Concha and calcined Haliotidis Concha are mainly the increase of CaCO₃ content， the transformation of CaCO₃ aragonite crystal form to calcite crystal form and the absence of organic components after calcination， and the changes of calcined products and standard decoction are mainly the decrease of CaCO₃ content and the increase of Na₂CO₃ relative content. The method established in the study is applicable to the quality control of the shellfish medicines-decoction pieces- standard decoction， which provides a new idea for the study of quality control of dispensing granules of shellfish medicines.

ObjectiveTo explore the quantity-quality transfer process of medicinal materials， decoction pieces and standard decoction of Haliotidis Concha（Haliotis discus hannai） by analyzing the physical phase and compositional changes， so as to provide references for the effective control of its quality. MethodsA total of 20 batches of Haliotidis Concha（H. discus hannai） from different habitats were collected and prepared into corresponding calcined products and standard decoction， and the content of CaCO₃ of the three samples were determined and the extract yield and transfer rate of CaCO₃ were calculated. The changes in elemental composition and their relative contents were investigated by X-ray fluorescence spectrometry（XRF）， X-ray diffraction（XRD） was used to study the changes in the phase compositions of the three samples and to establish their respective XRD specific chromatogram. Fourier transform infrared spectrometry（FTIR） was used to study the changes in the chemical composition and content changes of the three samples and to establish their respective FTIR specific chromatogram， while combining hierarchical cluster analysis（HCA）， principal component analysis（PCA） and orthogonal partial least squares-discriminant analysis（OPLS-DA） to find the common and differential characteristics， in order to explore the quantity-quality transfer relationship in the preparation process of standard decoction of Haliotidis Concha（H. discus hannai）. ResultsThe CaCO₃ contents of the 20 batches of medicinal materials， decoction pieces and standard decoction of Haliotidis Concha（H. discus hannai） were 93.87%-98.95%， 96.02%-99.97% and 38.29%-51.96%， respectively， and the extract yield of standard decoction was 1.71%-2.37%， and the CaCO₃ transfer rate of decoction pieces-standard decoction was 0.68%-1.27%. XRF results showed that the elemental species and their relative contents contained in Haliotidis Concha and its calcined products had a high degree of similarity， and although there was no obvious difference in the elemental species contained in decoction pieces and standard decoction， the difference in the relative contents was obvious， which was mainly reflected in the decrease of the relative content of element Ca and the increase of the relative content of element Na. XRD results showed that Haliotidis Concha mainly contained CaCO₃ of aragonite and calcite， while calcined Haliotidis Concha only contained CaCO₃ of calcite， and standard decoction mainly contained CaCO₃ of calcite and Na₂CO₃ of natrite. FTIR results showed that there were internal vibrations of O-H， C-H， C=O， HCO₃^- and CO₃^2- groups in Haliotidis Concha， while O-H， HCO₃^- and CO₃^2- groups existed in the calcined products and standard decoction. ConclusionThe changes of Haliotidis Concha and calcined Haliotidis Concha are mainly the increase of CaCO₃ content， the transformation of CaCO₃ aragonite crystal form to calcite crystal form and the absence of organic components after calcination， and the changes of calcined products and standard decoction are mainly the decrease of CaCO₃ content and the increase of Na₂CO₃ relative content. The method established in the study is applicable to the quality control of the shellfish medicines-decoction pieces- standard decoction， which provides a new idea for the study of quality control of dispensing granules of shellfish medicines.

Objective To investigate the impact of intergenerational caregiving on the brain structure and function of grandparents,and to analyze its correlation with caregiving factors.Methods Healthy adults(66 with grandchildren,24 without grandchildren)were recruited as study subjects,and clinical and MRI data were collected.Resting-state brain functional degree centrality(DC)and surface-based morphometry(SBM)methods were used to compare the differences in brain structure and function between the groups with and without grandchildren.The correlation between the differences in brain regions and △ values with grandchild's age,number,and time spent in childcare were assessed,respectively.Results Compared to the group without grandchildren,the group with grandchildren showed reduced surface area and cortical volume in the left middle temporal gyrus,as well as decreased DC values in the left medial superior frontal gyrus,bilateral orbital superior frontal gyrus,and left anterior cingulate and paracingulate gyrus(P＜0.05),respectively.In the grandchildren group,DC values and △ values in the left orbital superior frontal gyrus,left anterior cingulate and paracingulate gyrus were significantly positively correlated with time spent in childcare.Conclusion The brain structures and functions of grandparents related to empathy and motivation are changed in intergenerational caregiving,which may reveal the neuroplasticity after caring for their grandchildren.

Objective To investigate the impact of intergenerational caregiving on the brain structure and function of grandparents,and to analyze its correlation with caregiving factors.Methods Healthy adults(66 with grandchildren,24 without grandchildren)were recruited as study subjects,and clinical and MRI data were collected.Resting-state brain functional degree centrality(DC)and surface-based morphometry(SBM)methods were used to compare the differences in brain structure and function between the groups with and without grandchildren.The correlation between the differences in brain regions and △ values with grandchild's age,number,and time spent in childcare were assessed,respectively.Results Compared to the group without grandchildren,the group with grandchildren showed reduced surface area and cortical volume in the left middle temporal gyrus,as well as decreased DC values in the left medial superior frontal gyrus,bilateral orbital superior frontal gyrus,and left anterior cingulate and paracingulate gyrus(P＜0.05),respectively.In the grandchildren group,DC values and △ values in the left orbital superior frontal gyrus,left anterior cingulate and paracingulate gyrus were significantly positively correlated with time spent in childcare.Conclusion The brain structures and functions of grandparents related to empathy and motivation are changed in intergenerational caregiving,which may reveal the neuroplasticity after caring for their grandchildren.

In recent years, the incidence of cancer in China has been increasing steadily. Advancing primary prevention measures for cancers could be an effective strategy to curb this trend. Diet has been considered a modifiable and shared risk factor for various cancers. Studying dietary patterns, with consideration of the interactions between foods and nutrients, has a practical implication for cancer prevention. This study provided an overview of dietary pattern extraction methods, summarized the research findings on the association between dietary patterns and cancers in the digestive system, respiratory system, and genitourinary system, and elucidated the potential mechanisms underlying these associations, in order to provide scientific references for future research in this field.

In recent years, the incidence of cancer in China has been increasing steadily. Advancing primary prevention measures for cancers could be an effective strategy to curb this trend. Diet has been considered a modifiable and shared risk factor for various cancers. Studying dietary patterns, with consideration of the interactions between foods and nutrients, has a practical implication for cancer prevention. This study provided an overview of dietary pattern extraction methods, summarized the research findings on the association between dietary patterns and cancers in the digestive system, respiratory system, and genitourinary system, and elucidated the potential mechanisms underlying these associations, in order to provide scientific references for future research in this field.

Cancer is one of the leading causes of morbidity and mortality worldwide. Due to population aging, lifestyle variation and other factors, the morbidity and mortality of cancer continue to rise in China, resulting in a serious public health problem threating people's health. In response to this increasingly serious problem, tremendous efforts have been made in China, including the development of a series of policies and measures for specific needs of cancer prevention and treatment. Currently, China's strategy to reduce the disease burden of cancer mainly focuses on primary and secondary prevention. This paper summarizes the current status of disease burden of cancer and the performance of three-grade cancer prevention in China.