BACKGROUND:Bone tissue loss caused by tumors and trauma can have an adverse effect on postoperative rehabilitation.Therefore,scaffold materials are usually implanted during treatment.However,the existing implant materials are relatively simple and lack antibacterial properties.Early implantation may lead to iatrogenic autoinfection and have an adverse effect on osteogenesis.OBJECTIVE:To construct a KR-12-a5 polypeptide-nanohydroxyapatite-small intestinal submucosa composite scaffold and evaluate its feasibility as a material for promoting bone defect repair.METHODS:The small intestinal submucosa scaffold and the small intestinal submucosa scaffold containing 25,50,and 100 mg/mL nanohydroxyapatite(referred to as nHA-SIS scaffold)were prepared by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride/N-hydroxysuccinimide cross-linking method.The appropriate scaffold was screened for subsequent experiments by mechanical property testing.The antibacterial properties of KR-12-a5 polypeptide solution against Staphylococcus aureus,Streptococcus gordonii,and Fusobacterium nucleatum were detected.The nHA-SIS scaffolds were immersed in 250,500,and 1 000 μg/mL KR-12-a5 peptide solutions for 24 hours,and then freeze-dried to obtain peptide-loaded nanohydroxyapatite-porcine small intestinal submucosa composite scaffolds(denoted as P-nHA-SIS scaffolds).The sustained-release properties of the three groups of scaffolds were characterized.The nHA-SIS scaffolds and the three groups of P-nHA-SIS scaffolds were co-cultured with Staphylococcus aureus,Streptococcus gordonii,and Fusobacterium nucleatum for 24 hours or 48 hours.The scaffolds with strong antibacterial ability were screened by live and dead bacteria staining and scanning electron microscopy for subsequent experiments.The degradation properties and water absorption rates of the uncross-linked small intestinal submucosa scaffolds,cross-linked small intestinal submucosa scaffolds,nHA-SIS scaffolds,and P-nHA-SIS scaffolds were characterized.The extracts of cross-linked small intestinal submucosal scaffolds,nHA-SIS scaffolds,and P-nHA-SIS scaffolds were co-cultured with MC3T3-E1 cells.CCK-8 assay and live-dead cell staining were performed.The effects of the extracts of the three scaffolds on the migration of MC3T3-E1 cells were detected by Transwell chamber assay.RESULTS AND CONCLUSION:(1)The elastic modulus and compressive strength of 25,50,and 100 mg/mL nHA-SIS scaffolds were higher than those of small intestinal submucosal scaffolds(P＜0.05),among which the elastic modulus and compressive strength of 25 mg/mL nHA-SIS scaffolds were the highest,and this group of scaffolds were selected for subsequent experiments to load peptides.(2)KR-12-a5 peptide had strong antibacterial activity against common bacteria in bone defects(Staphylococcus aureus,Streptococcus gordonii,and Fusobacterium nucleatum).The three groups of P-nHA-SIS scaffolds all had sustained release properties.With the increase of peptide mass concentration,the antibacterial property of P-nHA-SIS scaffold was enhanced.Among them,the P-nHA-SIS scaffold loaded with 500 μg/mL peptide had achieved a satisfactory antibacterial effect,and this group of scaffolds would be selected in the future.(3)The degradation rate of the three groups of cross-linked scaffolds was lower than that of the uncross-linked scaffolds,and the water absorption rate was greater than that of the uncross-linked scaffolds.P-nHA-SIS scaffolds could promote the proliferation and migration of MC3T3-E1 cells without affecting the activity of MC3T3-E1 cells.(4)The results show that P-nHA-SIS scaffolds have strong antibacterial properties and the ability to promote the proliferation and migration of MC3T3-E1 cells,and are expected to be used in bone defect repair.

Objective To establish the HPLC fingerprints for the different extracts from Coptidis Rhizoma，and investigate the spectrum-effect relationship between HPLC fingerprints and anti-Staphylococcus aureus activity in vitro to analyze the pharmacodynamic material basis. Methods Nine kinds of Coptidis Rhizoma extracts were prepared, and establish the HPLC fingerprints for them. The antibacterial rate of each extract was determined by the broth microdilution method with Staphylococcus aureus as the test bacteria. The grey relational analysis （GRA） method was used to analyze the correlation between the fingerprint data and the in vitro antibacterial test data. Results The HPLC fingerprints of nine kinds of Coptidis Rhizoma extracts were established, nine common characteristic fingerprint peaks were calibrated, and 5 peaks were identified by the reference substance comparison method. GRA analysis experiments showed that the correlation between nine peaks and antibacterial effect was 0.559 1~0.803 3; and the peak 3, peak 8 （palmatine hydrochloride）, peak 9 （berberine hydrochloride） were positively correlated with the inhibition of Staphylococcus aureus,while the peak 9 （berberine hydrochloride） had the strongest effect, and its correlation degree was 0.803 3. Conclusion The effective substance of antibacterial was preliminarily determined through the study of spectrum-effect relationship for Coptidis Rhizoma extracts,which may be the alkaloids, mostly containing hydrochloride, which provided a reference for further research on the pharmacodynamic material basis of Coptidis Rhizoma.

Objective To explore the clinical factors influencing complete response in patients with locally advanced rectal cancer (LARC) after neoadjuvant chemoradiotherapy (nCRT). Methods Clinical data of LARC patients treated in the Department of Radiation Oncology at Beijing Shijitan Hospital between January 2013 and December 2024 were retrospectively collected. All patients received nCRT, after which surgery or a watch-and-wait approach was adopted based on treatment response. Univariable and multivariable logistic regression analyses were performed to identify prognostic factors influencing complete response. A clinical prediction model was constructed based on the multivariable analysis results, and its predictive performance was evaluated using the receiver operating characteristic curve. Results A total of 113 eligible patients were included. After nCRT, 19 patients (16.8%) achieved complete response, including 3 with clinical complete response and 16 with pathological complete response. Univariable analysis indicated that pretreatment clinical N stage, extramural venous invasion, carcinoembryonic antigen level, and neoadjuvant treatment regimen were associated with complete response after nCRT (P<0.05). Multivariable logistic regression analysis identified pretreatment extramural venous invasion, carcinoembryonic antigen level, and neoadjuvant treatment regimen as independent influencing factors for complete response (P<0.05). A prediction model incorporating these independent factors yielded an area under the receiver operating characteristic curve of 0.813 (95% confidence interval: 0.713-0.913), with a sensitivity of 89.5% and a specificity of 60.6%, demonstrating good predictive performance. Conclusion Pretreatment extramural venous invasion, carcinoembryonic antigen level, and neoadjuvant treatment regimen are independent factors influencing complete response after nCRT in LARC patients. The prediction model combining these factors may assist in evaluating treatment efficacy following nCRT in LARC patients.

Objective To explore the relationship between circadian rhythm genes and the occurrence, development, prognosis, and tumor microenvironment (TME) of lung adenocarcinoma (LUAD). Methods The Cancer Genome Atlas data were used to evaluate the expression, copy number variation, and somatic mutation frequency of circadian gene sets in LUAD. Gene ontology, Kyoto encyclopedia of genes and genomes, and gene set enrichment analysis were used to explore the potential mechanisms by which circadian rhythm genes affected LUAD progression. Cox regression, least absolute shrinkage and selection operator regression, support vector machine recursive feature elimination, and random forest screened circadian genes and established prognostic models, and on this basis constructed nomogram to predict patients’ 1-, 3-, and 5-year survival rates. Kaplan-Meier survival curves, receiver operating characteristic (ROC) curves, and time-dependent ROC curves were drawn to evaluate the predictive ability of the model, and the external dataset of GEO further verified the prognostic value of the prediction model. In addition, we evaluated the association of the prognostic model with immune cells and immune checkpoint genes. Single cell RNA sequencing (scRNA-seq) analysis was used to explore the molecular characteristics between prognostically relevant circadian genes and different immune cell populations in TME. Results Differentially expressed circadian rhythm genes were mainly enriched in biological processes related to cGMP-PKG signaling pathway, lipid and atherosclerosis, and JAK-STAT signaling pathway. Seven circadian rhythm genes: LGR4, CDK1, KLF10, ARNTL2, RORA, NPAS2, PTGDS were screened out, and a RiskScore model was established. According to the median RiskScore, samples were divided into a high-risk group and a low-risk group. Compared with patients in the low-risk group, patients in the high-risk group showed a poorer prognosis (P<0.001). Immunological characterization analysis showed that there were differences in the infiltration of multiple immune cells between the low-risk group and high-risk group. Most immune checkpoint genes had higher expression levels in the high-risk group than those in the low-risk group, and RiskScore was positively correlated with the expression of CD276, TNFSF4, PDCD1LG2, CD274, and TNFRSF9, and negatively correlated with the expression of CD40LG and TNFSF15. The scRNA-seq analysis showed that RORA and KLF10 were mainly expressed in natural killer cells. Conclusion The prognostic model based on seven feature circadian rhythm genes has certain predictive value for predicting survival of LUAD patients. Dysregulated expression of circadian genes may regulate the occurrence, progression as well as prognosis of LUAD through affecting TME, which provides a possible direction for finding potential strategies for treating LUAD from the perspective of mechanism by which circadian disorder affects immune cells.

ObjectiveTo investigate the epidemiological characteristics and influencing factors of depressive symptoms among middle school (junior, senior, and vocational high school) students in Yunnan Province, China, and to inform evidence-based intervention strategies for adolescent mental health. MethodsA cross-sectional survey was conducted between October and November 2023 using stratified random cluster sampling. Students from eight counties (districts) across four prefectures (cities) in Yunnan Province were included. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale (CES-D). Multivariate logistic regression analysis was performed to examine factors associated with depressive symptoms, with stratified analyses conducted by gender, educational stage, and ethnicity. ResultsA total of 4 672 questionnaires were distributed, with 4 670 valid questionnaires retrieved, yielding a valid response rate of 99.96%. The surveyed participants were predominantly female students (50.81%), junior high school students (49.13%), ethnic minorities (52.78%), and urban residents (79.29%). The mean CES-D score for middle school students in Yunnan Province was (15.31±10.83). Female students had a significantly higher mean score (16.63±11.41) than male students (13.95±10.02) (P<0.001). Senior high school students had a significantly higher mean score (16.61±10.61) compared to both junior high school students (14.74±11.45) and vocational high school students (13.10±7.71) (all pairwise comparisons P<0.001). The prevalence of depressive symptoms among middle school students in Yunnan Province was 28.18%. The prevalence was significantly higher in females (34.09%) than in males (22.07%). By school type, the detection rate was highest among senior high school students (33.39%), followed by junior high school students (26.29%) and vocational high school students (17.27%) (P<0.05). Multivariate logistic regression analysis showed that female gender (OR=2.16, 95%CI: 1.86‒2.50), being in junior high school (OR=2.43, 95%CI: 1.84‒3.20) or senior high school (OR=2.27, 95%CI: 1.73‒2.98), not living with parents (OR=1.24, 95%CI: 1.07‒1.44), irregular breakfast consumption (OR=1.52, 95%CI: 1.33‒1.75), lack of moderate-to-vigorous physical activity (MVPA) (OR=1.69, 95%CI: 1.37‒2.09), sleep duration ≤5 h per night (OR=2.52, 95%CI: 2.02‒3.14) or 6‒7 h per night (OR=1.47, 95%CI: 1.25‒1.73), smoking (OR=1.86, 95%CI: 1.56‒2.23), and alcohol consumption (OR=1.81, 95%CI: 1.54‒2.13) were positively associated with depressive symptoms. In contrast, screen time ≤1 h (OR=0.71, 95%CI: 0.59‒0.86) was negatively associated with depressive symptoms. Stratified analyses showed that female students not living with parents (OR=1.29, 95%CI: 1.06‒1.58), senior high school students (OR=1.51, 95%CI: 1.21‒1.88), and Han Chinese students (OR=1.37, 95%CI: 1.11‒1.69) were more likely to experience depressive symptoms. Han Chinese students who smoked were also more likely to have depressive symptoms (OR=1.72, 95%CI: 1.34‒2.21). In contrast, male students with screen time ≤1 h (OR=0.71, 95%CI: 0.53‒0.95) and ethnic minority students (OR=0.74, 95%CI: 0.58‒0.95) were less likely to experience depressive symptoms. Regardless of gender, irregular breakfast consumption, lack of MVPA, sleep duration less than 8 h per night, smoking, and alcohol consumption were all positively associated with depressive symptoms (P<0.05). Among both junior and senior high school students, irregular breakfast consumption, lack of MVPA, smoking, and alcohol consumption were positively associated with depressive symptoms (all P<0.05), while screen time ≤1 h was negatively associated with depressive symptoms (all P<0.05). For junior high school students, engaging in 1‒2 days of MVPA per week, screen time more than 2 h per day, and sleep duration 6‒7 h per night were all positively associated with depressive symptoms (all P<0.05). Among junior high, senior high, and vocational high school students, sleep duration ≤5 h per night was positively associated with depressive symptoms (P<0.05). For both Han Chinese and ethnic minority students, irregular breakfast consumption, lack of MVPA, sleep duration less than 8 h per night, and alcohol consumption were all positively associated with depressive symptoms (all P<0.05). ConclusionThe prevalence of depressive symptoms among middle school students in Yunnan Province is comparable to that in central China and higher than that in northern regions. Prevention and control efforts should prioritize female students and those in junior and senior high school stages. Universal improvements in lifestyle behaviors among middle school students, such as regular breakfast consumption, MVPA, sufficient sleep (≥8 h), and abstinence from smoking and alcohol. Particular attention should be given to limiting excessive screen time among junior high school students and addressing the mental health needs of females not living with their parents, senior high school students, and Han Chinese students.

Background Meteorological factors are among the key extrinsic triggers for the onset and exacerbation of cardiovascular and cerebrovascular diseases (CVD). Against the backdrop of sustained global warming, elucidating the impact of ambient temperature and atmospheric pressure on CVD, especially on pre-hospital CVD emergent events, has become imperative for evidence-based prevention and emergency preparedness. Objective To quantify the temporal trends of daily mean temperature and atmospheric pressure and their associations with pre-hospital CVD emergent events in Yantai, and to explore effect modification by demographic subgroups and geographic areas, thereby providing an empirical basis for the rational allocation of emergency medical resources. Methods Pre-hospital CVD emergency data from January 1, 2016 to December 31, 2022 were selected from the Yantai 120 Emergency Medical Command System. Synchronous meteorological factors and environmental pollutant data were obtained from the websites of the National Oceanic and Atmospheric Administration and the National Centers for Environmental Information of the United States. Time-series analysis combined with distributed lag non-linear model was used to analyze the association between daily temperature, atmospheric pressure, and pre-hospital CVD emergencies. Average annual percentage changes (AAPC) were calculated using Joinpoint (version 5.2.0.0) to reflect temporal trends. Spearman correlation analysis was employed to screen variables with low collinearity for inclusion in the multi-pollutant adjusted models. Results From 2016 to 2022, a total of 268275 pre-hospital CVD emergency cases were recorded in Yantai City, showing an increasing annual trend (AAPC=7.16%, P=0.002). Emergency volume, daily temperature, atmospheric pressure, and PM₁₀ displayed marked seasonal patterns, with summer bottoms and winter peaks for emergencies, daily temperature higher in summer and lower in winter, and the inverse for atmospheric pressure. Correlation analysis showed that both daily temperature and atmospheric pressure were positively correlated with O₃, with correlation coefficients of 0.745 and 0.723, respectively; negatively correlated with PM_2.5, with correlation coefficients of −0.246 and −0.235, respectively; and negatively correlated with PM₁₀, with correlation coefficients of −0.241 and −0.229, respectively (P < 0.05). A U-shaped correlation was revealed between daily temperature and pre-hospital CVD emergency risk. Using 24 °C as the reference, risk was elevated at both low and high daily temperatures, with the strongest cold effect at –11 ℃ (RR=1.53, 95%CI: 1.35, 1.73) and strongest heat effect at 30 ℃ (RR=1.06, 95%CI: 1.01, 1.11); cold effects were prolonged (lag0–14d) compared to heat effects. Atmospheric pressure exhibited a positive association with emergencies; using a median of 1012.2 hPa as the reference, the maximum risk occurred at 1037 hPa (RR=1.25, 95%CI: 1.03, 1.52), with a 0–5 d lag. In the subgroup analysis, the impact of low temperature was more pronounced among females (RR_{−9 ℃}=1.66), people over 60 years (RR_{−9 ℃}=1.91), and rural residents (RR_{−9 ℃}=1.76). High atmospheric pressure significantly increased the risk of pre-hospital CVD emergency among females (RR_{1035 hPa}=1.54), people under 18 years (RR_{1035 hPa}=3.62), and rural residents (RR_{1035 hPa}=1.46). The sensitivity analysis results indicated that, after excluding the impact of pandemic and the degrees of freedom for time variations, the effects of daily average temperature and atmospheric pressure on pre-hospital CVD emergency volume were consistent with the primary analysis findings. Conclusion Both non-optimal temperature and atmospheric pressure significantly increase the pre-hospital CVD emergency volume; therefore, emergency medical services should develop targeted response protocols, optimize resource allocation, and intensify public health education to mitigate the pre-hospital burden attributable to temperature and pressure fluctuations.

BACKGROUND:Bone tissue loss caused by tumors and trauma can have an adverse effect on postoperative rehabilitation.Therefore,scaffold materials are usually implanted during treatment.However,the existing implant materials are relatively simple and lack antibacterial properties.Early implantation may lead to iatrogenic autoinfection and have an adverse effect on osteogenesis.OBJECTIVE:To construct a KR-12-a5 polypeptide-nanohydroxyapatite-small intestinal submucosa composite scaffold and evaluate its feasibility as a material for promoting bone defect repair.METHODS:The small intestinal submucosa scaffold and the small intestinal submucosa scaffold containing 25,50,and 100 mg/mL nanohydroxyapatite(referred to as nHA-SIS scaffold)were prepared by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride/N-hydroxysuccinimide cross-linking method.The appropriate scaffold was screened for subsequent experiments by mechanical property testing.The antibacterial properties of KR-12-a5 polypeptide solution against Staphylococcus aureus,Streptococcus gordonii,and Fusobacterium nucleatum were detected.The nHA-SIS scaffolds were immersed in 250,500,and 1 000 μg/mL KR-12-a5 peptide solutions for 24 hours,and then freeze-dried to obtain peptide-loaded nanohydroxyapatite-porcine small intestinal submucosa composite scaffolds(denoted as P-nHA-SIS scaffolds).The sustained-release properties of the three groups of scaffolds were characterized.The nHA-SIS scaffolds and the three groups of P-nHA-SIS scaffolds were co-cultured with Staphylococcus aureus,Streptococcus gordonii,and Fusobacterium nucleatum for 24 hours or 48 hours.The scaffolds with strong antibacterial ability were screened by live and dead bacteria staining and scanning electron microscopy for subsequent experiments.The degradation properties and water absorption rates of the uncross-linked small intestinal submucosa scaffolds,cross-linked small intestinal submucosa scaffolds,nHA-SIS scaffolds,and P-nHA-SIS scaffolds were characterized.The extracts of cross-linked small intestinal submucosal scaffolds,nHA-SIS scaffolds,and P-nHA-SIS scaffolds were co-cultured with MC3T3-E1 cells.CCK-8 assay and live-dead cell staining were performed.The effects of the extracts of the three scaffolds on the migration of MC3T3-E1 cells were detected by Transwell chamber assay.RESULTS AND CONCLUSION:(1)The elastic modulus and compressive strength of 25,50,and 100 mg/mL nHA-SIS scaffolds were higher than those of small intestinal submucosal scaffolds(P＜0.05),among which the elastic modulus and compressive strength of 25 mg/mL nHA-SIS scaffolds were the highest,and this group of scaffolds were selected for subsequent experiments to load peptides.(2)KR-12-a5 peptide had strong antibacterial activity against common bacteria in bone defects(Staphylococcus aureus,Streptococcus gordonii,and Fusobacterium nucleatum).The three groups of P-nHA-SIS scaffolds all had sustained release properties.With the increase of peptide mass concentration,the antibacterial property of P-nHA-SIS scaffold was enhanced.Among them,the P-nHA-SIS scaffold loaded with 500 μg/mL peptide had achieved a satisfactory antibacterial effect,and this group of scaffolds would be selected in the future.(3)The degradation rate of the three groups of cross-linked scaffolds was lower than that of the uncross-linked scaffolds,and the water absorption rate was greater than that of the uncross-linked scaffolds.P-nHA-SIS scaffolds could promote the proliferation and migration of MC3T3-E1 cells without affecting the activity of MC3T3-E1 cells.(4)The results show that P-nHA-SIS scaffolds have strong antibacterial properties and the ability to promote the proliferation and migration of MC3T3-E1 cells,and are expected to be used in bone defect repair.

Objective To explore the incidence rate and independent risk factors of synchronous multiple early gastric cancer (SMEGC) in patients with early gastric cancer, and to provide evidence for early screening and intervention of high-risk population. Methods A retrospective analysis was performed on 308 patients with early gastric cancer who received treatment in the hospital from March 2019 to March 2024. The incidence rate of SMEGC was counted, and the risk factors were analyzed by univariate and multivariate Logistic regression analyses. Results Among the 308 patients with early gastric cancer in this study, 23 cases were SMEGC and 285 were single early gastric cancer, which were included in the SMEGC group and the single group respectively. The incidence rate of SMEGC was 7.47% (23/308). Compared with the single group, the proportions of male, smoking history, tumor diameter≤2 mm, chronic atrophic gastritis and intestinal metaplasia degree were higher in the SMEGC group (2=4.331、8.608、4.618、6.490、4.897，P=0.037、0.003、0.032、0.001、0.027). Logistic regression analysis suggested that chronic atrophic gastritis (OR=3.133, 95%CI: 1.240-7.918) and moderate-to-severe intestinal metaplasia (OR=3.171, 95%CI: 1.252-8.029) were independent risk factors for SMEGC (P<0.05). Conclusion Some patients with early gastric cancer are SMEGC. Chronic atrophic gastritis and moderate-to-severe intestinal metaplasia are independent risk factors affecting the occurrence of SMEGC. It is recommended to regularly screen high-risk patients and optimize management strategies to reduce the risk of SMEGC.

OBJECTIVE To provide a reference for optimizing and promoting the quality standards of Shechuan naolitong granules. METHODS Fifteen batches of Shechuan naolitong granules were used as samples to establish HPLC fingerprints using the Similarity Evaluation System for Chromatographic Fingerprint of Traditional Chinese Medicine （2012 edition）. Similarity evaluation and common peak identification were performed， and orthogonal partial least squares discriminant analysis （OPLS-DA） was used to assess quality differences among different batches and to screen quality differential components. Using salvianolic acid B（SAB） as the internal reference， quantitative analysis of multi-components by single-marker （QAMS） was developed to simultaneously determine geniposidic acid （GA）， chlorogenic acid （CA）， vaccarin （VA）， ferulic acid （FA） and senkyunolide I （SI）. The results were compared with those obtained by the external standard method. RESULTS A total of 13 common peaks were identified in the HPLC fingerprints of 15 batches of samples， and the similarities of the spectra were all above 0.96. Seven chromatographic peaks were identified as GA （peak 3）， CA （peak 6）， VA （peak 8）， FA （peak 9）， SI （peak 11）， SAB（peak 12） and TA（peak 13）. OPLS-DA indicated that the differential quality markers among 15 batches were peaks 5， 11 （SI）， and 12 （SAB）.Using SAB as the internal reference， the relative correction factors for GA， CA， VA， FA and SI were calculated as 1.058 4， 0.594 3， 0.643 3， 0.342 7 and 0.262 8， respectively. The mean content of GA， CA， VA， FA， SI and SAB across the 15 batches of samples were 0.155 0， 0.085 4， 0.140 3， 0.071 8， 0.072 7， 1.276 3 mg/g， respectively， showing no significant difference compared with the ESM （P＞0.05）. CONCLUSIONS The established HPLC fingerprint and QAMS are simple， efficient and economical， providing a reference for the quality control and further development of Shechuan naolitong granules.

Objective To compare the impact of NaClO and EDTA pretreatment on the enamel surfaces pore exposure rate,resin in-filtration effectiveness and shear bond strength between the enamel white spot lesions(WSLs)and resin composite.Methods A total of 104 sound premolars were selected for the study.4 mm×4 mm×2 mm enamel blocks from 64 sound premolars were cut in the center of the buccal surfaces of the teeth.All blocks were randomly divided into five groups:group SE(sound enamels as negative control);group DE(enamel blocks demineralised as positive control);group RI(resin infiltration);group N/RI(5.25％NaClO pretreatment and resin infiltration)and group E/RI(17％EDTA pretreatment and resin infiltration).The pore exposure rate of enamel surfaces and resin penetration depths were observed by scanning electron microscopy(SEM)and confocallaser scanning microscopy(CLSM)in each group.The remaining 40 premolars were cut from the cervical roots and the residual crowns were embedded in self-condensing resin ma-terial(buccal surfaces of the enamel exposed only).According to the grouping information,the samples were given the corresponding pretreatments and resin infiltration respectively and were bonded with a cylindrical resin cylinder on the buccal enamel surface for shear bond test.The shear bond strength and fracture modes were recorded and analyzed in each group.Results Compared to group RI,the pore exposure rate of the enamel surface,resin penetration depths,and percentage of resin penetration area in the N/RI and E/RI groups were significantly increased(P＜0.05).The shear bond strength of the samples in group SE was the highest,and the lowest in group DE.Compared to group DE,the shear bond strength in groups RI,N/RI,and E/RI was significantly increased(P＜0.05).Con-clusion Enamel surface pretreatment with 5.25％NaClO or 17％EDTA has been demonstrated to effectively enhance the enamel pore exposure rate,resin penetration depth and the shear bond strength between WSLs and resin composite.