ObjectiveThis study leverages structural data from antigen-antibody complexes of the influenza A virus neuraminidase (NA) protein to investigate the spatial recognition relationship between the antigenic epitopes and antibody paratopes. MethodsStructural data on NA protein antigen-antibody complexes were comprehensively collected from the SAbDab database, and processed to obtain the amino acid sequences and spatial distribution information on antigenic epitopes and corresponding antibody paratopes. Statistical analysis was conducted on the antibody sequences, frequency of use of genes, amino acid preferences, and the lengths of complementarity determining regions (CDR). Epitope hotspots for antibody binding were analyzed, and the spatial structural similarity of antibody paratopes was calculated and subjected to clustering, which allowed for a comprehensively exploration of the spatial recognition relationship between antigenic epitopes and antibodies. The specificity of antibodies targeting different antigenic epitope clusters was further validated through bio-layer interferometry (BLI) experiments. ResultsThe collected data revealed that the antigen-antibody complex structure data of influenza A virus NA protein in SAbDab database were mainly from H3N2, H7N9 and H1N1 subtypes. The hotspot regions of antigen epitopes were primarily located around the catalytic active site. The antibodies used for structural analysis were primarily derived from human and murine sources. Among murine antibodies, the most frequently used V-J gene combination was IGHV1-12*01/IGHJ2*01, while for human antibodies, the most common combination was IGHV1-69*01/IGHJ6*01. There were significant differences in the lengths and usage preferences of heavy chain CDR amino acids between antibodies that bind within the catalytic active site and those that bind to regions outside the catalytic active site. The results revealed that structurally similar antibodies could recognize the same epitopes, indicating a specific spatial recognition between antibody and antigen epitopes. Structural overlap in the binding regions was observed for antibodies with similar paratope structures, and the competitive binding of these antibodies to the epitope was confirmed through BLI experiments. ConclusionThe antigen epitopes of NA protein mainly ditributed around the catalytic active site and its surrounding loops. Spatial complementarity and electrostatic interactions play crucial roles in the recognition and binding of antibodies to antigenic epitopes in the catalytic region. There existed a spatial recognition relationship between antigens and antibodies that was independent of the uniqueness of antibody sequences, which means that antibodies with different sequences could potentially form similar local spatial structures and recognize the same epitopes.

ObjectiveTo investigate the effects of different fermentation methods and times on the fungal flora and chemical composition of Aurantii Fructus， in order to obtain the optimal fermentation conditions and flora structure， and to ensure the stability and controllability of the fermented varieties. MethodsScanning electron microscopy was used to observe and analyze the colony characteristics on the surface of Aurantii Fructus under different fermentation conditions. Internal transcribed spacer 2（ITS2） high-throughput sequencing， combined with fungal community diversity analysis and fungal community structure analysis， were used to obtain the fungal flora microbial categories of Aurantii Fructus under the conditions of traditional pressure-shelf fermentation and non-pressure-shelf natural fermentation for 7， 14， 21 d（numbered Y1-Y3 for the former， and numbered F1-F3 for the latter）， respectively. At the same time， the chemical components in the fermentation process were detected by ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry（UPLC-Q-TOF-MS/MS）， combined with principal component analysis（PCA）， partial least squares-discriminant analysis（PLS-DA） and compound retention time， parent ions， characteristic fragment ions and other information， the differential compounds between the different fermentation samples were screened and identified. ResultsThe analysis of fungal community diversity showed that the dominant flora did not change at different fermentation time points in the traditional pressure-shelf fermentation method， while in the non-pressure-shelf natural fermentation method， there was a significant difference with the fermentation process， and at the genus level， the dominant genus of samples Y1， Y2， Y3 and F2 was Aspergillus， while the dominant genera of samples F1 and F3 were both Rhizopus. This indicated that the microbial growth environment provided by the traditional fermentation method was more stable， and the microbial community structure was more stable， which was more conducive to the stable and controllable fermentation process and fermented products. A total of 155 compounds were identified by compositional analysis， including 70 flavonoids， 38 coumarins， 10 alkaloids， 34 organic acids and 3 other compounds. After fermentation， two new components of ribalinine and pranferin were produced. Different fermentation conditions also brought about differences in chemical composition， multivariate statistical analysis obtained 26 differential compounds under two different fermentation methods， mainly including flavonoids， organic acids and coumarins. Comprehensively， the microbial community structure of samples fermented by the traditional pressure-shelf method of Aurantii Fructus for 14 d was stable， the species richness was high and the overall content of differential compounds was high， which was the optimal processing condition. ConclusionCompared with non-pressure-shelf natural fermentation， the traditional method has obvious advantages in terms of the stability of the microbial community structure and the content of chemical compounds， and the optimal condition is 14 days of fermentation. This study is helpful to promote the quality stability and fermentation bioavailability of fermented products of Aurantii Fructus， as well as to provide an experimental basis for the further improvement of the quality control methods of this variety.

ObjectiveTo investigate the effects of different fermentation methods and times on the fungal flora and chemical composition of Aurantii Fructus， in order to obtain the optimal fermentation conditions and flora structure， and to ensure the stability and controllability of the fermented varieties. MethodsScanning electron microscopy was used to observe and analyze the colony characteristics on the surface of Aurantii Fructus under different fermentation conditions. Internal transcribed spacer 2（ITS2） high-throughput sequencing， combined with fungal community diversity analysis and fungal community structure analysis， were used to obtain the fungal flora microbial categories of Aurantii Fructus under the conditions of traditional pressure-shelf fermentation and non-pressure-shelf natural fermentation for 7， 14， 21 d（numbered Y1-Y3 for the former， and numbered F1-F3 for the latter）， respectively. At the same time， the chemical components in the fermentation process were detected by ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry（UPLC-Q-TOF-MS/MS）， combined with principal component analysis（PCA）， partial least squares-discriminant analysis（PLS-DA） and compound retention time， parent ions， characteristic fragment ions and other information， the differential compounds between the different fermentation samples were screened and identified. ResultsThe analysis of fungal community diversity showed that the dominant flora did not change at different fermentation time points in the traditional pressure-shelf fermentation method， while in the non-pressure-shelf natural fermentation method， there was a significant difference with the fermentation process， and at the genus level， the dominant genus of samples Y1， Y2， Y3 and F2 was Aspergillus， while the dominant genera of samples F1 and F3 were both Rhizopus. This indicated that the microbial growth environment provided by the traditional fermentation method was more stable， and the microbial community structure was more stable， which was more conducive to the stable and controllable fermentation process and fermented products. A total of 155 compounds were identified by compositional analysis， including 70 flavonoids， 38 coumarins， 10 alkaloids， 34 organic acids and 3 other compounds. After fermentation， two new components of ribalinine and pranferin were produced. Different fermentation conditions also brought about differences in chemical composition， multivariate statistical analysis obtained 26 differential compounds under two different fermentation methods， mainly including flavonoids， organic acids and coumarins. Comprehensively， the microbial community structure of samples fermented by the traditional pressure-shelf method of Aurantii Fructus for 14 d was stable， the species richness was high and the overall content of differential compounds was high， which was the optimal processing condition. ConclusionCompared with non-pressure-shelf natural fermentation， the traditional method has obvious advantages in terms of the stability of the microbial community structure and the content of chemical compounds， and the optimal condition is 14 days of fermentation. This study is helpful to promote the quality stability and fermentation bioavailability of fermented products of Aurantii Fructus， as well as to provide an experimental basis for the further improvement of the quality control methods of this variety.

Background The decline of physical activity in the elderly due to aging may increase the risk of sarcopenia. Currently, there is a lack of evidence from large natural populations on the relationship between PA and sarcopenia. Objective To explore the relationship between PA and sarcopenia in the elderly aged 60 years and above in 10 provinces (autonomous regions) of China. Methods Data were retrieved from the 2022—2023 round of the China Development and Nutrition Health Impact Cohort. Personal basic information and PA data were collected by questionnaire survey. Skeletal muscle mass was measured by bio-electrical impedance analysis, muscle strength was measured using a grip dynamometer, and physical performance was reflected by 6-meter walk speed. The Asian Working Group for Sarcopenia (AWGS) 2019 criteria were used to diagnose sarcopenia. Light physical activity (LPA) duration, moderate-to-vigorous physical activity (MVPA) duration, and total physical activity volume were calculated. A total of 3326 residents aged ≥60 years with complete data were selected as the survey participants. Multiple logistic regression models and restricted cubic splines (RCS) were used to assess the association between PA duration/volume and sarcopenia. Results In 10 provinces (autonomous regions) of China, the prevalence of sarcopenia in the elderly aged 60 years and above was 5.5% (95%CI: 4.7%, 6.2%). The logistic regression analysis showed that compared with the elderly reporting 0-7.0 h·week⁻¹ in LPA duration, the risk of sarcopenia in the elderly with LPA duration of >14.0-21.0 h·week⁻¹ was reduced by 51% (OR=0.49, 95%CI: 0.26, 0.96). Compared with the elderly with total physical activity ≥15.0 metabolic equivalent of task (MET)-h·week⁻¹, those with <7.5 MET-h·week⁻¹ had a 2.24-fold increased risk of sarcopenia (OR=2.24, 95%CI: 1.17, 4.29). The RCS results found that LPA duration and total physical activity volume each showed a nonlinear dose-response relationship with the risk of sarcopenia (P_overall<0.05, P_non-linear<0.05). Compared with the elderly with an LPA duration of 0 h· week⁻¹, the risk of sarcopenia in the elderly with an LPA duration of 12.6 h· week⁻¹ was the lowest (OR=0.42, 95%CI: 0.21, 0.83). Compared with the elderly with a total physical activity volume of 15.0 MET-h· week⁻¹, the elderly with a total physical activity volume of 46.0 MET-h· week⁻¹ had the lowest risk of sarcopenia (OR=0.57, 95%CI: 0.38, 0.84). There was no statistically significant association between weekly MVPA duration and the risk of sarcopenia (P>0.05). Conclusion Increasing weekly LPA duration and total physical activity volume would help to reduce the risk of sarcopenia.

Objective To explore the mediating role of activities of daily living (ADL) in pain and depressive symptoms in the elderly in China. Methods Utilizing the data from 2020 China Health and Retirement Longitudinal Study, 4403 Chinese elderly individuals aged ≥ 60 years old were selected as the research subjects. Depression Scale (CES-D 10) of the Center for Epidemiological Survey and ADL scale were used in the study. The PROCESS4.1 macro was used to test the mediating effect of daily living activities between pain and depressive symptoms, and the Bootstrap method was applied for verification of the mediating variables. Results A total of 2368 cases of depressive symptoms were detected in the elderly in China, with a detection rate of 53.78%. Pain was positively correlated with depressive symptoms (r=0.27, P<0.01), and activities of daily living were negatively correlated with pain and depressive symptoms (r=-0.27, -0.337, P<0.01). The results showed that the total effect value of pain on depressive symptoms was 0.33, the direct effect value was 0.24, and the mediating effect value of daily living activities was 0.09, accounting for 27.27%. Conclusion Pain and activities of daily living are important factors influencing depressive symptoms in the elderly, and activities of daily living play a partial mediating role in the relationship between pain and depressive symptoms in the elderly.

Objective　To explore the mediating role of cognitive function in the association between literacy level and depressive symptoms in middle-aged and elderly people in China. Methods　 Using the fourth national follow-up data of the China Health and Elderly Care Tracking Survey 2018, 8 124 middle-aged and elderly people aged 45 years and above were included as the study subjects. The PROCESS 4.0 program was used to test the mediating effect of cognitive function between literacy level and depressive symptoms, and the Bootstrap method was used for the mediator variable validation. Results The detection rate of depressive symptoms among middle-aged and elderly people in China was 38.10%. After controlling for gender, place of residence, marital status, smoking, alcohol consumption, and exercise, literacy level was a negative predictor of depressive symptoms in middle-aged and elderly people (β =－0.480, t =－11.248, P<0.001). Cognitive function accounted for 58.75% of the amount of mediating effect between literacy level and depressive symptoms. Conclusion 　Literacy level and cognitive function are associated with depressive symptoms in middle-aged and elderly people. Literacy level can influence depressive symptoms directly or indirectly through the mediation of cognitive dysfunction.

Objective To explore the different latent class and characteristics of the cognitive ability level of undergraduate nursing students in hospice care based on the individual-centered perspective,and analyze its influencing factors to provide the reference for the formulation of targeted nursing education.Methods Nursing students in a medical university in Yunnan Province were selected from March 2023 to June 2023.The general data questionnaire and hospice care knowledge questionnaire were used to conduct a cross-sectional survey.SPSS and Mplus were used for the data analysis.Results Three latent class of hospice care cognitive ability were identified,which were named as hospice care high cognitive ability group,general cognitive ability group,and low cognitive ability group,accounting for 28.74%,57.29%,and 13.97%,respectively;Nursing students'gender,nationality,place of residence,earning and practice experience of hospice care(whether they had the contact with end-stage cancer patients,whether they had received the hospice care related training),and whether they were willing to engage in the hospice care related work were the influencing factors of different potential categories of cognitive ability of hospice care among nursing students(P<0.05).Conclusion There are three latent class of hospice care cognitive ability of nursing students.Male minority nursing students who have not been exposed to end-stage cancer patients and have not received the hospice care-related training,are unwilling to engage in the hospice care-related work.Male ethnic minority nursing students residing in rural areas have the weaker cognitive levels of hospice care.Scholars in the future can formulate targeted training strategies according to different latent class of hospice care cognitive ability to improve nursing students'hospice care cognitive ability and reserve talents for hospice care teams.

Objective To investigate the role of HK2 and VDAC1 in diacetylmorphine-induced cardiomyocyte apoptosis.Methods A dose-escalation method was used to establish a rat model of diacetylmorphine addiction.Forty SD rats were randomly divided into three groups,the normal group(n=10)was injected with an equal amount of saline subcutaneously,the model group(n=15)was injected with 5 mg/kg of diacetylmorphine for the first time,and then the dose was increased by 2.5 mg/(kg·d)day by day for 20 days,and the group of model +10 D(n=15)continued to increase the dose based on the model group up to the 10th day.Lactate dehydrogenase(LDH)and glutamic oxaloacetic transaminase(GOT)were detected by ELISA;HE staining was used to observe the pathological changes of myocardial tissues in each group;TUNEL staining was used to detect apoptosis in myocardial tissues in each group;and immunohistochemistry,RT-q-analysis,and immunochemistry were used to detect apoptosis in myocardial tissues in each group.Immunohistochemistry,RT-qPCR and Western bl-ot were used to detect the mRNA and protein expression of HK2,VDAC1 and apoptosis-related factors.Results HE staining revealed that myocardial tissues exhibited different degrees of damage with the prolongation of diacetylmorphine intervention.Compared with the normal group,serum LDH,GOT content and myocardial apoptosis rate increased in the model group,mRNA and protein levels of HK2 and anti-apoptotic factor Bcl-2 decreased,mRNA and protein levels of VDAC1 and pro-apoptotic factors Bax and Caspase-3 increased,and the protein level of Clevead Caspase-3 increased;in the model +10 D group the above indexes,there was a statistically significant difference(P<0.05).Conclusion Diacetylmorphine can cause cardiomyocyte apoptosis,and VDAC1 may be involved in the process of cardiomyocyte apoptosis caused by diacetylmorphine.

Objective To observe the effects of Gegen Qinlian Decoction on pancreatic endoplasmic reticulum stress in mice with type 2 diabetes mellitus(T2DM);To explore its mechanism of action in the treatment of T2DM.Methods Totally 75 SPF male db/db mice were randomly divided into model group,metformin group,and Gegen Qinlian Decoction high-,medium-,low-dosage groups,with 15 mice in each group.15 db/m mice were set as the blank group.The administration groups received corresponding medicine for gavage for 12 weeks.Body mass,fasting blood glucose(FBG)and glycated hemoglobin(HbA1c)in mice were detected,HE staining was used to observe the pathological changes of pancreatic tissue,the apoptosis of islet cells was determined by TUNEL staining,Western blot was used to detect pancreatic tissue glucose regulatory protein 78(GRP78),protein kinase R-like endoplasmic reticulum kinase(PERK),p-PERK,activated transcription factor 4(ATF4)and C/EBP homologous protein(CHOP)protein expression,RT-PCR was used to detect pancreatic tissue PERK,ATF4,CHOP mRNA expressions.Results Compared with the blank group,the body mass,FBG and HbA1c contents in the model group significantly increased(P<0.01);the pancreatic tissue structure was incomplete,with blurry boundaries and vacuoles inside,leading to a significant increase in pancreatic islet cells apoptosis(P<0.01);the expressions of GRP78,p-PERK,ATF4,and CHOP proteins in pancreatic tissue significantly increased(P<0.01),and the mRNA expressions of PERK,ATF4 and CHOP significantly increased(P<0.01).Compared with the model group,the body mass,FBG and HbA1c contents of mice in each administration group significantly decreased(P<0.05,P<0.01);pathological changes in pancreatic tissue was reduced,and islet cells apoptosis decreased to varying degrees(P<0.05,P<0.01);the expressions of GRP78,p-PERK,ATF4 and CHOP proteins in pancreatic tissue significantly decreased(P<0.01)in Gegen Qinlian Decoction high-and medium-dosage groups and the metformin group,and the expressions of PERK,ATF4 and CHOP mRNA significantly decreased(P<0.05,P<0.01).Conclusion Gegen Qinlian Decoction may decreased pancreatic islet cells apoptosis,protect pancreatic cell function,and delay the progression of T2DM by inhibiting the endoplasmic reticulum stress PERK/ATF4/CHOP signaling pathway,and down-regulating the expressions of related genes and proteins.

Objective To investigate the changing trend and epidemiological characteristics of the incidence and mortality of chronic kidney disease (CKD) with age, period and birth cohort in Chinese population. Methods Based on the data of incidence and mortality of CKD in Chinese population aged 20-80 years from 1990 to 2019 in GHDx database, joinpoint regression model was used to analyze the incidence and mortality trend of CKD. An age-period-cohort model was constructed to analyze the effects of age, period, and birth cohort on the trend of CKD incidence and mortality. Results Joinpoint regression analysis showed that the standardized incidence rate of chronic kidney disease in Chinese population increased from 146.37/100 000 in 1990 to 161.52/100 000 in 2019, while the standardized mortality rate decreased from 12.98/100 000 in 1990 to 11.23/100 000 in 2019. The APC model analysis showed that the risk of CKD incidence and death in the Chinese population increased with age, while the risk of CKD incidence increased with the increase of period. The risk of death did not change significantly with the increase of period. The cohort born later had a lower risk of CKD incidence and death compared to the cohort born earlier. Conclusion At present, the age effect and period effect of the incidence and death risk of chronic kidney disease in China are dominant. It is important to take effective measures and intervene in a timely manner, especially to strengthen the protection of older high-risk groups born earlier.