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Objective@#To explore the association between circadian rhythm with depressive and anxiety symptoms of college students in Jinzhou City, to provide a theoretical basis for targeted depression and anxiety prevention among college students.@*Methods@#A total of 1 938 college students were selected by convenient sampling method from November to December 2020 for questionnaire survey. The relationship between circadian rhythm and depression and anxiety symptoms was analyzed by using questionnaire,survey including Self Rating Depression Scale (SDS), Self Rating Anxiety Scale (SAS) and Munich Chronotype Questionnaire (MCTQ).@*Results@#There were significant differences in the distribution of depressive symptoms in different majors, smoking, drinking and physical exercise ( χ 2=46.80, 5.88, 5.76, 12.23, P <0.05). There were significant differences in the distribution of anxiety symptoms in different majors, smoking and drinking ( χ 2=9.41, 5.80, 5.56, P <0.05). Stratified analysis showed that the depressive symptoms of different chronotype were statistically varied by age, gender, professional, grade, registered residence, body mass index, smoking, drinking, and sports( χ 2=8.16, 14.42, 12.25, 6.19, 10.99, 15.29, 17.41, 15.63, 7.47, 9.59, 10.51 , P <0.05). The anxiety symptoms of different chronotype were statistically different in age (21 years) and smoking (no), ( χ 2= 8.34 , 7.16, P <0.05). Spearman rank correlation showed that the corrected Mid sleep on Free Days Corrected for Sleep Debt on Work Days (MSFsc) was positively correlated with the standard scores of depression and anxiety ( r s=0.10, 0.09), and social jet lag was positively correlated with the standard scores of depression and anxiety ( r s=0.09, 0.05)( P <0.05). After controlling for age, major, smoking and drinking, binary Logistic regression showed that mean sleep length was inversely correlated with depressive symptoms ( OR =0.82), and weekly insomnia frequency was positively correlated with depressive symptoms ( OR=1.14 ).Early type and intermediate type of chronotypes were negatively correlated with depression ( OR =0.66,0.57). Intermediate type of chronotype was negatively correlated with anxiety symptoms ( OR =0.65).@*Conclusion@#Circadian rhythm is related to depressive and anxiety symptoms,among which the average sleep length, early rise and intermediate sleep patterns are negatively related to depression symptoms, and intermediate sleep patterns and anxiety symptoms, suggesting that circadian rhythm disorder may affect depression and anxiety symptoms.
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Objective@#To study the computational fluid dynamics (CFD) characteristics of ultrasonic root canal irrigation when the file was placed at a certain depth in the root canal, to provide a reference for clinical application.@*Methods @#First, scanning laser vibrometry (SLV) was utilized to analyze the characteristics of vibrational ultrasonic files under specific power. Then ICEM CFD 18.0 software was used to establish the root canal ultrasonic irrigation model. The insertion position of the ultrasonic working tip was set 1 mm away from the physiological apical foramen, and cloud images of the results were obtained by FLUENT 18.0 software. Volume fraction, flow velocity and pressure in the root canal were evaluated after setting the computing conditions.@*Results@#The vibration of the ultrasonic working tip was mainly transverse vibration with slight longitudinal vibration. The amplitude of transverse vibration of each part of the working tip was different. Maximum values were observed at the apical end area of the file, and the closer to the base of the file, the smaller the amplitude. The area where the cavitation volume fraction of the rinsing fluid was greater than 0 was concentrated around the working point. The flow rate of the irrigating fluid was up to 2 m/s, within the area 0.2 mm in front of the working tip, the velocity of the irrigating fluid was greater than 0.1 m/s, while within the area 0.8 mm from the root tip, the velocity of the irrigating fluid was small or even zero. The apical pressure value was non-positive when the tip of the file was 1 mm away from the apical foramen in this model.@*Conclusion@# Based on the experimental results, it appears that when the ultrasonic working tip was placed 1 mm short of the working length, the ultrasonic irrigating flow did not overflow the root apical foramen and the irrigation process was relatively safe; the irrigation fluid had a strong irrigation effect within approximately 0.2 mm in front of the working tip.
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Objective@# To investigate the effects of graphene on the proliferation, migration and cell morphology of dental pulp stem cells (DPSCs).@*Methods@#Graphene powder was prepared by the oxidation-reduction method, and a 0.5 mg/mL graphene dispersion was prepared. Raman spectroscopy and atomic force microscopy were used to characterize the structure and surface morphology of graphene. DPSCs were isolated and cultured in vitro. MTT assay was used to detect the effects of different concentrations of graphene dispersions (0, 1, 5, 10, 20, 50, 100 μg/mL) on the proliferation and wound healing assay was used to detected the migration abilities of DPSCs. The effects of graphene on the morphology of DPSCs were observed by immunofluorescence staining. @*Results @# In the present study, compared with the control group (0 μg/mL), the proliferation of DPSCs in the 100 μg/mL group was inhibited at 72 h (P < 0.05), and the proliferation of DPSCs in the other groups was not significantly affected (P > 0.05). Graphene dispersions at 10 and 20 μg/mL promoted the migration of DPSCs (P < 0.05). After being cultured in 20 μg/mL graphene dispersions for 3 days, the DPSCs showed a large and orderly cytoskeletal structure, and the spread area of cells was not significantly different from that of the control group (0 μg/mL) (P > 0.05), while some cells had the morphological characteristics of nerve cells.@* Conclusion @# Graphene has good biocompatibility and is expected to be a suitable material for tissue engineering within fitting concentration.