Objective: To establish a method for determining the molecular weight and molecular weight distribution of Poly(Lactide-co-Glycolide Acid) (PLGA) using Size Exclusion Chromatography-Refractive Index-Multiangle Laser Light Scattering (SEC-RI-MALLS) and Size Exclusion Chromatography-Refractive Index (SEC-RID), and to compare the results obtained from these two methods.
Methods: For SEC-RI-MALLS, tetrahydrofuran was used as the mobile phase, Shodex GPC KF-803L was employed as the chromatographic column with a flow rate of 1 mL·min^-1, column temperature at 30 ℃, and an injection volume of 100 μL. For SEC-RID, tetrahydrofuran was also used as the mobile phase, Agilent PLgel 5 μm MIXD-D was used as the chromatographic column with a flow rate of 1 mL·min^-1, column temperature at 30 ℃, differential detector temperature at 35 ℃, and an injection volume of 20 μL. The molecular weight and molecular weight distribution were calculated using Agilent’s GPC software. The newly established methods were validated methodologically, and the molecular weight and molecular weight distribution of 13 batches of samples were determined.
Results: The precision, accuracy, stability, and repeatability tests for SEC-RI-MALLS showed RSD values of 1.35%, 1.58%, 1.53%, and 1.26%, respectively. The SEC-RID method exhibited good linearity (r=0.999 9), with RSD values for precision, accuracy, stability, and repeatability tests (n=6) of 2.05%, 1.62%, 1.30%, and 2.97%, respectively. The results obtained from SEC-RI-MALLS were lower than those from SEC-RID, and the molecular weight distribution coefficient was smaller, but the results from the paired T-test performed with the value measured by SEC-RID method and the value measured by SEC-RI-MALLS method multiplied a conversion coefficient of 1.5 showed no significant difference between the two methods.
Conclusion: Both methods are stable and reliable, and can be used for the determination of PLGA molecular weight and molecular weight distribution based on the specific situations.

Objective: To analyze the change trends in the body shape indicators and proportions of students in Harbin from 2010 to 2024, and to investigate ergonomic compatibility of functional dimensions of school desks and chairs with current student shape indicators, so as to provide a reference for revising furniture standards of desks and chairs. Methods: Between September and November of both 2010 and 2024, a combination of convenience sampling and stratified cluster random sampling was conducted across three districts in Harbin, yielding samples of 6 590 and 6 252 students, respectively. Anthropometric shape indicators cluding height, sitting height, crus length, and thigh length-and their proportional changes were compared over the 15-year period. The 2024 data were compared with current standard functional dimensions of school furniture. The statistical analysis incorporated t-test and Mann-Whitney U- test. Results: From 2010 to 2024, average height increased by 1.8 cm for boys and 1.5 cm for girls; sitting height increased by 1.5 cm for both genders; crus length increased by 0.3 cm for boys and 0.4 cm for girls; and thigh length increased by 0.5 cm for both genders. The ratios of sitting height to height, and sitting height to leg length increased by less than 0.1 . The difference between desk chair height and 1/3 sitting height ranged from 0.4-0.8 cm. Among students matched with size 0 desks and chairs, 22.0% had a desk to chair height difference less than 0, indicating that the desk to chair height difference might be insufficient for taller students. The differences between seat height and fibular height ranged from -1.4 to 1.1 cm; and the differences between seat depth and buttock popliteal length ranged from -9.8 to 3.4 cm. Among obese students, the differences between seat width and 1/2 hip circumference ranged from -20.5 to -8.7 cm, while it ranged from -12.2 to -3.8 cm among non obese students. Conclusion Current furniture standards basically satisfy hygienic requirements; however, in the case of exceptionally tall and obese students, ergonomic accommodations such as adaptive seating allocation or personalized adjustments are recommended to meet hygienic requirements.

Objective To analyze the economic cost of self-monitoring of gestational diabetes mellitus, and provide a basis for measuring the economic burden of gestational diabetes mellitus, and to provide a reference for the formulation of intervention development and the adjustment of resource allocation. Methods The individual economic cost of self-monitoring for gestational diabetes mellitus was measured based on a decision tree model, and the total economic cost of self-monitoring for gestational diabetes mellitus in Beijing was estimated. The uncertainty of the model parameters was analyzed using one-way sensitivity analysis. Results The average individual economic cost of gestational diabetes self-monitoring was 1184 RMB, and the individual cost incurred by choosing different types of blood glucose meters ranged from 403 to 18 000 RMB. The average individual economic cost of finger-stick blood glucose monitoring was 606 RMB and the average individual economic cost of continuous glucose monitoring was 2 374 RMB. The total economic cost of gestational diabetes self-monitoring in Beijing was 23.818 0 million RMB, and the total economic cost incurred by choosing different types of blood glucose meters ranged from 0.292 5 to 9.027 9 million RMB. The proportion of the finger-stick blood glucose monitoring had the greatest impact on the robustness of the results. Conclusion Finger-stick blood glucose monitoring is still the dominant self-monitoring method and is less costly than continuous glucose monitoring. Self-monitoring of pregnant women with gestational diabetes mellitus incurs certain economic cost and causes an economic burden on society.

Background In the context of the innovation-driven development strategy, occupational groups are facing increasing work pressure, and its impact on sleep quality and mental health deserves attention. Objective To explore potential mediating role of sleep quality between work stress and mental health status among occupational workers, and to provide a scientific basis for improving their mental health status. Methods Cluster sampling was used to select 2000 workers in Urumqi, Xinjiang Uygur Autonomous Region. They were divided into mental and physical worker groups according to their occupational types, and a questionnaire survey was conducted using General Information Survey Forms, Effort Reward Imbalance scale (ERI), Pittsburgh Sleep Quality Index (PSQI), and Symptom Check List-90 (SCL-90). Work stress level, sleep quality, and mental health were assessed and compared between mental and physical workers. Structural equation modelling was used to evaluate the relationship among work stress, sleep quality and mental health of the workers, and to explore the mediating effect of sleep quality. Results A total of 1979 survey questionnaires were collected, with a response rate of 99%, including 1500 (75.8%) mental workers and 479 (24.2%) physical workers. Linear correlations were confirmed between work stress, mental health, and sleep quality. The correlations of work stress with mental health and sleep quality scale scores were positive for both mental and physical workers (r=0.32, 0.31, P<0.01; r=0.25, 0.25, P<0.01), and sleep quality was also positively correlated with mental health (r=0.47, 0.56, P<0.01) . The final modified structural equation model showed that the coefficients of work stress on sleep quality for the mental and physical workers were 0.56 and 0.46 (P<0.001) respectively, and the coefficients of sleep quality on mental health were 0.52 and 0.80 (P<0.001) respectively. Sleep quality mediated the impact of work stress on mental health of the mental and physical workers, with mediating effect values of 0.29 and 0.37 respectively. The adaptability of both structural equation models is less than 3. Conclusion Occupational population's work stress and mental health may be mediated by sleep quality, and measures should be taken to reduce work stress and improve sleep quality and mental health.

ObjectiveTo analyze the epidemiological characteristics of hand, foot, and mouth disease (HFMD) in Zhangjiakou City, Hebei Province from 2013 to 2022, so as to provide a basis for HFMD prevention, control, and evaluation of intervention effectiveness. MethodsHFMD data of Zhangjiakou City from 2013 to 2022 were collected. Descriptive statistics and the Joinpoint regression model were used to analyze the trend of the epidemic. ResultsThe incidence of HFMD in Zhangjiakou was predicted to decrease with APC=-14.86% in 2013‒2022. The top five regions with the highest incidence showed varying trends: Qiaodong District (APC=-26.21%), Qiaoxi District (APC=-18.29%), Xuanhua District (APC=-14.28%), Chicheng District (APC=-18.68%), and Zhuolu County (APC=51.43% in 2013‒2016, APC=-14.27% in 2016‒2022), indicating a downward trend. Three age groups showed an upward trend in incidence: the 0-year-old group (APC=-42.82% in 2013‒2016, APC=16.54% in 2016‒2022), the 7-year-old group (AAPC=9.60%), and the 9-year-old group (AAPC=12.76%). HFMD cases occurred throughout the year, peaking from June to August, with July being the most significant month. The male-to-female ratio was1.40∶1, with no statistical difference (χ²=5.932, P>0.05). A high incidence was in children under 5 years old, with those aged 1‒4 years being the main affected group. In terms of occupation, scattered children (6 245 cases, 57.65%) and preschool children (3 653 cases, 33.72%) were the most affected. A total of 504 laboratory-confirmed cases were reported, with a detection rate of 4.65% (504/10 832). The composition of confirmed cases included CoxA 16 (193 cases, 38.29%), EV71 (75 cases, 14.88%), and other enteroviruses (236 cases, 46.83%). ConclusionFrom 2013 to 2022, HFMD in Zhangjiakou City showed a downward trend with clear seasonal, regional, and occupational distributions. It is suggested that epidemic monitoring should be strengthened, etiological detection should be enhanced, and education efforts in key areas should be improved. High-incidence counties should analyze data and conduct risk assessments effectively.

Objective To investigate the current situation and health effects of indoor microbial pollution in Xi'an, to analyze the purification effect of air purifiers on indoor microbial pollution, and to provide reference for improving the indoor environment. Methods Through stratified random sampling, 20 families from rural areas and 20 families from upwind and downwind urban areas respectively were selected from Xi'an. Data was collected by questionnaire surveys and on-site environmental sampling. Non-parametric analysis and correlation analysis were used for statistical analysis. Results Overall, the standard-exceeding rate of total count of bacteria was 5.00%. The medians of the total count of bacteria and fungi were 312.50 cfu/m3 and 260.00 cfu/m³, respectively. In terms of health effects, the correlation between rhinitis and cold with total bacterial count was statistically significant (P<0.05), with the correlation coefficients of 0.182 and 0.223, respectively. Purification effect of air purifiers on microbial pollution was statistically significant (P<0.05). After opening for 2 hours, the total numbers of bacteria and fungi decreased significantly. Conclusion The occurrence risk of colds and rhinitis is increased by indoor microbial pollution. Air purifiers have a certain effect on decreasing the total number of bacteria and fungi. It is recommended to use air purifiers with high CADR of particulate matter, double-layer filter and sterilization and dehumidification function, and replace the filters regularly to reduce indoor microbiological contamination.

OBJECTIVE To evaluate the pharmacodynamics of Wujiashen Gejiejing on rats with deficiency of lung qi. METHODS The rat model of deficiency of lung qi was established by sawdust fumigation. By comparing the general activity state, blood acid-alkali indexes, biochemical indexes related to chronic bronchitis and airway histological characteristics of rats in each group, the pharmacodynamics of Wujiashen Gejiejing on rats with deficiency of lung qi was evaluated. RESULTS Compared with model group, after the Wujiashen Gejiejing intervention, the body weight of the rats significantly increased; the levels of p(O2) and SaO2 in blood were significantly increased(P<0.001), p(CO2) was significantly decreased(P<0.05), and pH had a tendency to increase; the levels of endothelin(ET) and IL-1β in serum were significantly decreased(P<0.01 or P<0.05), and the levels of TNF-α in serum had a decreasing trend. The damaged lung structures were significantly improved. CONCLUSION Wujiashen Gejiejing can significantly improve the activity state and improve hypoxemia and hypercapnia of lung qi deficiency syndrome, improve the damaged lung structure and the function of lung ventilation, and has obvious anti-inflammatory effect. Its mechanism may be related to regulating the expression of inflammatory cytokines IL-1β, TNF-α and ET.

Objective To investigate the predictive value of lactate/albumin ratio(LAR),interleukin-6(IL-6)and CD4+T lymphocyte count in 28-day mortality in patients with severe pneumonia and sepsis.Methods A total of 73 patients with severe pneumonia and sepsis admitted to the Respiratory Intensive Care Unit(RICU)of Zhengzhou Central Hospital Affiliated to Zhengzhou University from January 2022 to June 2023 were enrolled and divided into the survival group(n=43)and the death group(n=30)according to their 28-day outcomes.The clinical data of the patients were collected from their electronic medical records,including age,gender,comorbidities with hypertension,diabetes,and coronary artery heart disease(CHD),as well as sequential organ failure assessment(SOFA)score,acute physiology and chronic health evaluation Ⅱ(APACHE Ⅱ)score,mean arterial pressure(MAP),confusion,uremia,respiratory rate,blood pressure,age ≥65 years(CURB-65)score,total bilirubin(Tbil),serum creatinine(Scr),platelet count(PLT),white blood cell(WBC)count,procalcitonin(PCT),and C-reactive protein(CRP)at admission to RICU.On the 1st,3rd,and 7th day after admission to RICU,the patients'arterial blood was drawn,and the lactate level was detected by a fully automated blood gas analyzer.The peripheral venous blood was drawn,and the serum albumin and IL-6 levels were detected by enzyme-linked immunosorbent assay,and the CD4+T lymphocyte subset count was measured by flow cytometry.The LAR of patients on the 1st,3rd and 7th day was calculated.The clinical data of the patients and the LAR,IL-6 level and CD4+T lymphocyte count on the 1st,3rd,and 7th day were compared between the two groups.The influencing factors of 28-day mortality in patients with severe pneumonia and sepsis were analyzed by logistic regression,and the predictive value of each influencing factor on the 28-day mortality in patients with severe pneumonia and sepsis was evaluated by the receiver operating characteristic(ROC)curve.Results There was no significant difference in gender,age,proportions of comorbidities with hypertension,diabetes and CHD,length of stay in RICU,and Tbil,MAP,PLT,Scr,WBC,PCT and CRP at admission to RICU(P＞0.05).The APACHE Ⅱ and CURB-65 scores of the patients in the death group were significantly higher than those in the survival group(P＜0.05).On the 1st,3rd and 7th day,the CD4+T lymphocyte count in the death group was significantly lower than that in the survival group,while the SOFA score was significantly higher than that in the survival group(P＜0.05).On the first day,there was no significant difference in the LAR and IL-6 level be-tween the death group and the survival group(P＞0.05).However,on the 3rd and 7th day,the LAR and IL-6 level in the death group were significantly higher than those in the survival group(P＜0.05).The LAR,IL-6 level and SOFA score on the 3rd and 7th day in the survival group were significantly lower than those on the 1st day,and these indicators on the 7th day were sig-nificantly lower than those on the 3rd day(P＜0.05);the CD4+T lymphocyte count on the 3rd and 7th day was significantly higher than that on the 1st day(P＜0.05),while it showed no significant difference on the 7th and 3r day(P＞0.05).The IL-6 level on the 7th day in the death group was significantly lower than that on the 1st and 3rd day(P＜0.05),while there was no significant difference in IL-6 level on the 1st day compared with the 3r day(P＞0.05);moreover,there was no significant difference in LAR,CD4+T lymphocyte count and SOFA score between each time point(P＞0.05).Pearson correlation analy-sis showed that on the 3rd day,the LAR and IL-6 level were significantly positively correlated with the SOFA score in patients with severe pneumonia and sepsis(r=0.385,0.394;P＜0.05).On the 7th day,the LAR and IL-6 level were also significantly positively correlated with the SOFA score(r=0.418,0.402;P＜0.05).On the 3 rd and 7 th day,CD4+T lymphocyte count was significantly negatively correlated with the SOFA score(r=-0.451,-0.454;P＜0.05).Logistic regression analysis showed that the APACHE Ⅱ score,LAR,IL-6 level and CD4+T lymphocyte count on the 3rd day,and the IL-6 level and CD4+T lym-phocyte count on the 7th day were the influencing factors for 28-day mortality in patients with severe pneumonia and sepsis(P＜0.05).The ROC curve showed that the APACHE Ⅱ score,LAR,IL-6 level and CD4+T lymphocyte count on the 3rd day and the combination of the three,IL-6 level and CD4+T lymphocyte count on the 7th day and the combination of the two had certain predictive value for the 28-day mortality in patients with severe pneumonia and sepsis(P＜0.05).The area under the ROC curve(AUC)of LAR,IL-6 level and CD4+T lymphocyte count on the 3rd day combined to predict 28-day mortality in patients with severe pneumonia and sepsis was 0.891,and the AUC of APACHE Ⅱ score for predicting 28-day mortality in pa-tients with severe pneumonia and sepsis was 0.769.The AUC values of LAR,IL-6 level and CD4+T lymphocyte count on the 3rd day for predicting 28-day mortality in patients with severe pneumonia and sepsis were 0.795,0.757 and 0.770,respective-ly,and the AUC values of IL-6 level and CD4+T lymphocyte count on the 7th day and their combination for predicting 28-day mortality in patients with severe pneumonia and sepsis were 0.743,0.802 and 0.888,respectively.Conclusion The 3-day LAR,IL-6 level and CD4+T lymphocyte count,and the 7-day IL-6 level and CD4+T lymphocyte count after admission are re-lated to the 28-day mortality in patients with severe pneumonia and sepsis.The combined LAR,IL-6 level and CD4+T lympho-cyte count on the 3rd day can better assess the severity and prognosis of patients.

Objective To study the correlation between the abnormal perfusion area detected by resting+regadenoson stress D-SPECT and the severity of coronary arterial lesions.Methods One hundred patients needing coronary angiography and PCI admitted in the cardiology department of First Hospital of He-bei Medical University from April 1,2022 to April 1,2023 were selected as the study subjects.The resting+regadenoson loading examination was performed by using the special cardiac machine D-SPECT.The patients were divided into the mild ischemia group(range＜10％),moderate ischemia group(range 10％-20％)and severe ischemia group(range＞20％)according to the proportion of sparse or defect appearance in myocardi-al segmental radionuclide distribution during regadenoson stress D-SPECT in comparison with resting exami-nation.The coronary arterial angiography was performed.The Gensini score was calculated.Results The Gensini score in the severe ischemia group was(55.70±20.60)points,which was higher than(41.88±28.07)points in the moderate ischemia group and(39.71±21.40)points in the mild ischemia group,and the differences were statistically significant(P＜0.05).There was no statistically significant difference in the Gensini score between the mild ischemia group and moderate ischemia group(P＞0.05).The mean stent length in the severe ischemia group was(30.50±7.47)mm,which was significantly higher than(20.90±4.72)mm in the mild ischemia group and(23.50±3.87)mm in the moderate ischemia group,and the differ-ences were statistically significant(P＜0.05).There was no statistically significant difference in the mean stent length between the mild ischemia group and moderate ischemia group(P＞0.05).Conclusion The abnormal perfusion area detected by resting+regadenoson stress D-SPECT is conducive to evaluate the severity of coro-nary arterial lesions and the length of needing implantation stent.

Objective To evaluate the role of quantitative flow ratio(QFR)in percutaneous coronary intervention(PCI)by using regadenoson stress dynamic single-photon emission computed tomography(D-SPECT).Methods We selected 200 patients with unstable angina admitted to Department of Cardiology,Hebei Medical University First Hospital,from June 31,2021 to June 31,2023 for elective PCI.The patients were aged 57.56±8.23 years and were randomly divided into a conventional group(n=100)and a QFR group(n=100)according to a random number table.The trial was conducted using a double-blind method.The conventional group received PCI treatment based on the experience of the physician,while the QFR group received PCI treatment based on the QFR measurement results.All enrolled patients underwent pre-operative and 7-day post-operative D-SPECT stress imaging using regadenoson stress D-SPECT,and their images were acquired from short axis,vertical long axis,and horizontal long axis to calculate the total myocardial perfusion score and the total myocardial ischemia segment number under the distribution of 17 myocardial segments.Results There was no significant difference in the number of myocardial ischemia segments(7.59±3.14 vs.7.48±3.36,P=0.811)or the total myocardial perfusion score(15.87±7.61 vs.15.63±5.97,P=0.860)between the two groups before PCI.The number of myocardial ischemia segments(5.58±3.36 vs.6.51±2.14,P=0.020)and the total myocardial perfusion score(10.55±4.41 vs.12.96±6.50,P=0.002)in the QFR group were significantly better than those in the conventional group 7 days after PCI(P＜0.05).Conclusion Applying QFR guidance for PCI can better improve the degree of myocardial ischemia in patients.