Objective:To investigate the influential factors of mental health in rural high-school students by structural equation modeling.Methods:447 rural high-school students were tested by Mental Health test,Adolescent Self-rating Life Events Check list,Social Support Scale and Trait Coping Style questionnaire,then theoretical model were established and confirmed for the relationships of life events,social support,coping styles and mental health of rural high-school students.Results:The structural equation modeling fitted the data very well(?2/df=3.56,GFI=0.940,AGFI=0.902,NFI= 0.913,CFI=0.901,RMSEA=0.048),the theoretical model suppose was supported by the use of structural equation modeling.Conclusion:Social supports and coping styles have direct influence on mental health of rural high-school students.Life events have indirect influence on mental health through social supports and coping styles.

Objective To study the localization of specific allergen of Dermatophagoides pteronyssinus. \ Methods\ Through optical microscope,the specific allergens of D.pteronyssinus were observed in paraffin sections using D.pteronyssinus\|specific IgE antibodies from the patient sera. \ Results and Conclusion \ The digestive system was found occupying large parts of body cavity of D.pteronyssinus by HE staining, while the specific allergens of D.pteronyssinus were mostly occurred in the midgut tissue, gut contents, cuticle and reproductive system in the immunostained sections. The results also showed that many parts of D. pteronyssinus were recognized by the specific IgE antibodies obtained from allergic individuals to D.pteronyssinus, which provided a theoretic base for further study of isolation and purification of the specific allergen.

To lay a foundation for the type selection of the ambulance helicopter. The type selection was explored from the aspects of platform selection, rescue environment and service requirements, analyzing the rescue in the helicopter and the tendency of the ambulance helicopter in foreign countries and China. The types of the am-bulance helicopter were determined as the specific and modified ambulances, with the considerations such as operation environment, flight performance, cabin structure, onboard equipment, cabin configuration, fixation device and protection. Specific ambulance helicopter is supposed to be based on small- or mediate-sized platform, while the modi-fied ambulance helicopter is supposed to be based on large or heavy platform.

ObjectiveTo rapidly detect the mutation frequency of DBC2 gene 7776C ＞ T in breast cancer and breast fibroadenoma by applying the mutation-sensitive molecular switch ( comprised of high-fidelity DNA polymerase and phosphorothioate-modified allele-specific primers) and agarose gel electrophoresis.Methods Allelic specific primers targeting mutation type and wild type were designed with the primers'3'terminal phosphorothioate modification.When the primers matched with the tissue DNA,the primers could be extended with highfidelity polymerase; when they mismatched with the tissue DNA,the primers could not be extended.DNA samples from 85 cases of breast cancer and 10 cases of breast fibroadenoma tissues were chosen and analyzed by PCR amplifications mediated by high-fidelity DNA polymerase.Gel imaging system was employed to make analysis of PCT products.ResultsThe mutation-sensitive molecular switch system showed that the mutation rate of 7776C ＞ T was 2.4％ ( 2/85 ) in the 85 cases of breast cancer,and no mutation was found in the 10 cases of breast fibroadenoma.ConclusionsThe mutation-sensitive molecular switch combined with agarose gel electrophoresis can rapidly detect the mutation of breast cancer DBC2 gene 7776C ＞ T.It is applicable in single nucleotide polymorphisms assay and has enormous application value in detecting gene mutation.

Abstract: Objective　To investigate the relationship between the body mass index (BMI) levels and the negative conversion time of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleic acid in adult coronavirus disease 2019 (COVID-19) patients and the asymptomatic persons. Methods　Asymptomatic infected patients and confirmed COVID-19 patients admitted to Chengdu Public Health Clinic Center from February 2021 to November 2021 were dynamically included. The epidemiological and clinical characteristics of the objects were collected, and the SARS-CoV-2 nucleic acid testing of the objects during their hospitalization was continuously monitored, and the negative nucleic acid conversion time was recorded. The t test or Wilcoxon rank sum test, χ2 test or Fisher's exact probability method examine were used to distribute characteristics of each group of variables and the connection between different variables, respectively. Then the variables showed differences in distribution (P<0.05) between different BMI groups were included in the multivariate Cox proportional risk regression model. Results　A total of 253 subjects ranged from 18 to 63 years old, with M(P25, P75) age of 37.0 (30.0, 47.0) years old, were included in this study. The male to female ratio was 4.16 to 1. The BMI was (23.97±3.33) kg/m2. 50.59% (128/253) of the objects were overweight or obese, and 78.13% (100/128) were overweight. The negative time of SARS-CoV-2 nucleic acid conversion of all subjects ranged from 1 to 71 days, with M(P25, P75) of 7.0 (2.0, 18.0) days (P<0.001). The negative time of SARS-CoV-2 nucleic acid conversion of the normal weight or the thin, and the overweight or obese were 5.00 (2.00, 19.00) and 8.00 (2.00, 17.75) days respectively. The results of multivariate Cox's proportional hazards regression model showed that the BMI levels may not be associated with the negative conversion time of SARS-CoV-2 nucleic acid (HR=1.090, 95%CI: 0.843-1.410, P=0.510). Conclusions　Adult asymptomatic persons and confirmed COVID-19 patients are mainly middle-aged and young males, and overweight or obesity is relatively common. Overweight or obesity cannot be considered as an independent factor influencing the negative conversion time of SARS-CoV-2 nucleic acid.

The oral administration of bioactive macromolecular drugs such as proteins, peptides and nucleic acids represents unprecedented challenges from the drug delivery point of view. One key consideration is how to overcome the gastrointestinal tract absorption barrier. Recent studies suggest that microfold cell (M cell), a kind of specialized antigen-sampling epithelial cell which is characterized by a high endocytic rate and low degradation ability, may play an important role in macromolecule oral absorption. The development of an in vitro M cell coculture system and its modified models greatly advanced the study of M cells and the development of oral delivery system for macromolecular drugs. The special structure, function and formation characteristics, and biomarkers of M cell are summarized in this review. The applications of in vitro M cell models in developing oral delivery system ofbioactive macromolecular drugs are discussed.

Objective To study the effects of serum on anticancer activity of DHA and its antitumor mechanism. Method The growth inhibition of DHA on lung cancer A549 cells,and the effect of DHA on serum-induced protein kinase B(Akt)activation were assessed by MTT and Western blot respectively. Results DHA markedly induced growth inhibition of A549 cells in low concentration of serum,but promoted growth of A549 cells in high concentration of serum. DHA significantly blocked serum-induced activation of Akt in serum-free medium. Conclusion Serum is obviously against DHA-mediated growth inhibition of A549 cells,and DHA inhibits activation of Akt by lipid peroxidation and blocks growth of A549 cells.

Objective The purpose of this study is to determine whether the quantitative parameters of salivary gland scintigraphy are useful in the diagnosis of Sjgren's syndrome(SS).Method Forty patients with SS and 29 control subjects underwent salivary gland scintigraphy.Two indices,uptake ratio and maximum se- cretion were mearsured.The optimal cut-points of both indices were derived from receiver operative character- istic curve(ROC).The diagnostic value of the indices was assessed by the area under ROC curve(AUC~(ROC)). Results The optimal cut-point of uptake ratio was 5.5～5.7.The optimal cut-point of maximum secretion was 0.20.The sensitivities of both indices were 86.2%～89.7%.The specificity of uptake ratio was 63.4%～65.9%. The specificity of maximum secretion was 82.9%～85.4%.The AUC\+\{RoC\} of uptake ratio was 0.780/0,776.The AUC\+\{ROC\} of maximum secretion was 0.905/0,899.Conclusion The quantitative parameters of salivary gland scintigraphy may be useful in the diagnosis of Sj(?)gren syndrome.

Adult ; Biopsy, Needle ; Diagnosis, Differential ; Humans ; Kidney ; pathology ; Kidney Diseases ; pathology ; therapy ; Male ; Nephritis, Interstitial ; pathology ; Renal Dialysis ; Sarcoidosis ; pathology ; therapy ; Tuberculosis, Renal ; pathology

OBJECTIVETo investigate the bond strengths of customized titanium bracket manufactured by selective laser melting.

METHODSEighty human premolars which had been extracted for orthodontic purpose were collected and divided randomly (by random table) into two groups (customized bracket group and 3M bracket group, 40 molars in each group). The 35% phosphoric acid was used for etching and the brackets were bonded with 3M Unitek bonding adhesive. All bonded specimens were placed in saline for 24 hours at room temperature and were tested on DWD3050 electronic testing machine to determine the shear bond strength and tensile bond strength. After debonding, the adhesive remnant indexes (ARI) were recorded.

RESULTSThe shear bond strengths of customized brackets was 6.80 (6.20, 8.32) MPa, which was significantly lower than that of the 3M brackets [10.46 (9.72, 11.48) MPa] (Z = -3.463, P < 0.05). And the tensile bond strengths of customized brackets was (6.93 ± 1.21) MPa, which was significantly higher than that of the 3M brackets [(5.88 ± 1.23) MPa] (t = 2.81, P < 0.05). No significant difference was found in the ARI between two different kinds of the brackets.

CONCLUSIONSThe shear bond strength and tensile bond strength of both kinds of brackets were enough for clinic application.

Acid Etching, Dental ; Adolescent ; Bicuspid ; Child ; Composite Resins ; chemistry ; Dental Bonding ; methods ; Dental Debonding ; Dentin-Bonding Agents ; chemistry ; Humans ; Lasers ; Orthodontic Brackets ; Phosphoric Acids ; chemistry ; Random Allocation ; Shear Strength ; Tensile Strength ; Titanium