Cyberbullying and its effect on health risk behaviors among secondary vocational school students / 中国学校卫生

Objective@#To investigate the current situation of cyberbullying and health risk behaviors among secondary vocational school students, to explore the effects of cyberbullying on health risk behaviors, so as to provide a reference for formulating intervention strategies to promote adolescent health related behaviors.@*Methods@#From March to April 2023, a field survey was conducted on 1 184 students from one secondary vocational school each in Jilin City and Yanji City by random cluster sampling method. The data was analyzed using Chi square tests and generalized linear models.@*Results@#Among secondary vocational school students, 839 individuals (70.9%) experienced the cyberbullying, and 1 036 individuals (87.5%) had one and more health risk behavior group. There was a positive correlation between cyberbullying and health risk behaviors ( r=0.60, P <0.01). The generalized linear model analysis showed that female and no Internet addiction were negatively correlated with the health risk behaviors of secondary vocational students ( β =-2.75, -8.90), and the single parent families and peer pressure was positively correlated with the health behaviors of secondary vocational students ( β =2.56, 4.82)( P ＜0.05). Secondary vocational students experienced cyberbullying who from single parent families, peer pressure and social oriented internet usage were more likely to engage in health risk behaviors ( β= 3.41, 4.88, 2.20, P <0.05).@*Conclusions@#The incidence of cyberbullying and health risk behaviors among secondary vocational school students is relatively high, and cyberbullying can influence the occurrence of health risk behaviors. It is important to focus on and implement guidance for internet use and health behavior education for secondary vocational students from multiple perspectives, including the family, school, and society. Corresponding intervention strategies should be taken to promote the healthy development of adolescents.

Patrinia scabiosaefolia Inhibits Growth of 5-FU-Resistant Colorectal Carcinoma Cells via Induction of Apoptosis and Suppression of AKT Pathway / 中国结合医学杂志

OBJECTIVE@#To investigate the effects of ethanol extract of Patrinia scabiosaefolia (EEPS) on chemo-resistance of colorectal cancer cells (CRC) and explore the possible molecular mechanisms.@*METHODS@#5-fluorouracil (5-FU)-resistant human colorectal carcinoma cell line (HCT-8/5-FU) and its parental cells HCT-8 were treated with EEPS (0, 0.25, 0.50, 1 or 2 mg/mL), or 5-FU (0, 100, 200, 400, 800 or 1600 μmol/L). The 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay was performed to evaluate the cell viability. Cell density was observed by phase-contrast microscope, cell counting and colony formation assay were used to determine the cell proliferation of HCT-8/5-FU cells treated with 0, 0.5, 1 or 2 mg/mL EEPS. Cell apoptosis was determined by Hoechst staining. Western-blot was performed to detect the phosphorylation of AKT as well as the protein expression level of B-cell CLL/lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax).@*RESULTS@#Compared with HCT-8 cells, MTT assay results indicated that HCT-8/5-FU cells were resistant to 5-FU treatment (P0.05). Moreover, compared with untreated HCT-8/5-FU cells, 1 and 2 mg/mL of EEPS treatment significantly reduced cell density, cell number, inhibited cell survival (P<0.05), and induced apoptosis in HCT-8/5-FU cells. Furthermore, 1 and 2 mg/mL of EEPS significantly decreased the phosphorylation level of p-AKT and Bcl-2 protein expression, and increased the expression of Bax protein (P<0.05).@*CONCLUSION@#EEPS is a promising therapeutic agent that may overcome chemo-resistance in cancer cells, likely through suppression of the AKT pathway and promotion of cancer cell apoptosis.

Biomechanical analysis on periodontal ligament in dynamic jaw / 医用生物力学

Objective To investigate the influences of loading time and loading angle on the stress, displacement of human periodontal ligament in dynamic jaw. Methods The three-dimensional assembly model of the mandible front teeth, periodontal ligament and alveolar bone was reconstructed by using the reverse engineering technology. The thickness of periodontal membranes was 0.2 mm. The stress, displacement at different positions of the periodontal ligaments during different jaw cycles were analyzed under dynamic load in the direction from bucca to tongue side with 0°, 15°, 30°, 45°, 60°, 75°, 90° angle to the long axis of the tooth. Results During one jaw cycle, the ratio of the maximum to minimum value of the maximum residual stress due to different loading angles was 5.5, and the ratio of the maximum to minimum value of the maximum displacement was 8.1. The ratio of the maximum to minimum value of the maximum displacement which was caused by five jaw cycles was increased in the range from 1.02 to 1.35 with the increase of loading angles. The ratio of the maximum to minimum value of the maximum residual stress which was caused by different loading angles was increased in the range from 1.86 to 3.00 with the increase of jaw cycles. The location of the maximum stress was at the tongue side of the cervical margin at different loading angles, and the location of the maximum residual stress was distributed at different positions of the cervical margin. Most stress was accumulated at the root of the periodontal ligament under the 0° dynamic load. Conclusions The situation of the accumulated residual stresses and the uncertainties in the distribution of the maximum residual stresses should be observed in the clinical choice of mandible incisors fixed by bridge abutments; large angle force applied to the tooth was harmful to the periodontal ligament and rapid succession of chewing hard food should be avoided as much as possible during the clinical treatment.

Effects of periodontal ligament thickness on mesial movement of mandibular first molar in lingual orthodontics / 医用生物力学

Objective To study the effects of the various thickness of periodontal ligament on stress and displacement of mandibular first molar and periodontal tissues during mesial movement of tooth in lingual orthodontics. Methods Based on the reverse engineering technology, the three-dimensional assembly models of the teeth, periodontal ligament and alveolar bone with the same height of alveolar bone were constructed, and thicknesses of the periodontal ligament was 0.15, 0.2, 0.25, 0.3 and 0.35 mm, respectively. The stress and displacement of periodontal ligament, root and surface of alveolar bone were analyzed under the condition of lingual tipping, rotation and translation movements. Results For the maximum stress of periodontal ligament, root and surface of alveolar bone due to different periodontal ligament thickness, the ratio of the maximum value to the minimum value was 1.46, 2.06 and 6.72, respectively. For the maximum displacement of root and the surface of alveolar bone, the ratio of the maximum value to the minimum value was 1.65 and 1.50, respectively. Corresponding with different thickness of periodontal ligament, the location of the maximum stress of root and periodontal tissues would change at root, periodontal furcation and tooth neck. Conclusions In clinical practice, changes of tooth neck, periodontal furcation and root should be observed carefully, and the translation movement is more conducive to the health of teeth and periodontal tissues for patients with thin thickness of periodontic ligament.