Objective To investigate the contamination status of cloth mouse pads in dental clinics,and provide theoretical basis for standardizing environmental surface disinfection and scientific intervention in dental clinics.Methods The contamination status of cloth mouse pads in 5 dental clinics were investigated by adenosine triphos-phate(ATP)fluorescence detection method,visual observation method,and bacterial culture method.Disinfection efficacy of ultraviolet disinfection method and wiping disinfection using two types of disinfectant wipes on cloth mouse pads and photovoltaic glass mouse pads was compared.Intervention measures(using photovoltaic glass mouse pads,regular cleaning and disinfecting)were taken,and contamination status of cloth mouse pads in different departments before and after intervention was compared.Results The baseline investigation found that the conta-mination status of mouse pads varied in different dental clinics.The qualified rate of bacterial culture of mouse pads in department of endodontics was the lowest(20.00％),followed by the department of periodontology(30.00％).There was statistically significant difference in ATP detection values between two types of disinfectant wipes before and after wiping and disinfecting photovoltaic glass mouse pads(both P＜0.001).After using photovoltaic glass mouse pads,the contamination of mouse pads in 5 dental clinics was alleviated,and the qualified rate of ATP detec-tion increased(＞80％),compared with qualified rate of ATP detection before intervention,differences were all sta-tistically significant(all P＜0.001).Conclusion The contamination of the cloth mouse pads in dental clinics is seri-ous,and the conventional cloth mouse pad is difficult to be cleaned and disinfected.It is suggested that medical in-stitutions use the mouse pad which is convenient for cleaning and disinfection,and specify the disinfection method and frequency to control the contamination of the mouse pads.

Objective To investigate the value of MRI of the sternal end of clavicle in bone age assessment in Chinese population,especially its applicability in the determination of criminal responsible age.Methods A total of 431 patients aged from 10.00 to 29.99 years with neck or chest MRI were retrospectively collected.According to the Schmeling grading method,the epiphyseal development of the clavicle MRI was divided into five grades.The consistency of methods was evaluated.The correlation and general descriptive analysis between MRI grades and age was analyzed.The sex difference was analyzed.Curve fitting was used to establish a nonlinear model between age and grades.Results The grades of clavicle MRI showed a significant age-related trend(Figure 2),and the correlation was 0.861(0.887 in males and 0.840 in females).Except for grade 1,there was no significant difference between males and females in other grades.The minimum age of male grade 3 was greater than 14 years old,and the minimum age of female grade 3 was greater than 16 years old.The minimum age in grade 4 and grade 5 was over 18 years old in both sexes.The best curve fitting model was cubic model for both sexes(R2=0.805 for men and 0.722 for women).Conclusion Clavicle MRI can be used for the assessment of bone age in Chinese population.Complete epiphyseal plate closure can be used as a reliable indicator for the determination of age at 18 years old,and it is expected to achieve radiation-free forensic bone age assessment.

Objective To investigate the contamination status of cloth mouse pads in dental clinics,and provide theoretical basis for standardizing environmental surface disinfection and scientific intervention in dental clinics.Methods The contamination status of cloth mouse pads in 5 dental clinics were investigated by adenosine triphos-phate(ATP)fluorescence detection method,visual observation method,and bacterial culture method.Disinfection efficacy of ultraviolet disinfection method and wiping disinfection using two types of disinfectant wipes on cloth mouse pads and photovoltaic glass mouse pads was compared.Intervention measures(using photovoltaic glass mouse pads,regular cleaning and disinfecting)were taken,and contamination status of cloth mouse pads in different departments before and after intervention was compared.Results The baseline investigation found that the conta-mination status of mouse pads varied in different dental clinics.The qualified rate of bacterial culture of mouse pads in department of endodontics was the lowest(20.00％),followed by the department of periodontology(30.00％).There was statistically significant difference in ATP detection values between two types of disinfectant wipes before and after wiping and disinfecting photovoltaic glass mouse pads(both P＜0.001).After using photovoltaic glass mouse pads,the contamination of mouse pads in 5 dental clinics was alleviated,and the qualified rate of ATP detec-tion increased(＞80％),compared with qualified rate of ATP detection before intervention,differences were all sta-tistically significant(all P＜0.001).Conclusion The contamination of the cloth mouse pads in dental clinics is seri-ous,and the conventional cloth mouse pad is difficult to be cleaned and disinfected.It is suggested that medical in-stitutions use the mouse pad which is convenient for cleaning and disinfection,and specify the disinfection method and frequency to control the contamination of the mouse pads.

Objective To investigate the value of MRI of the sternal end of clavicle in bone age assessment in Chinese population,especially its applicability in the determination of criminal responsible age.Methods A total of 431 patients aged from 10.00 to 29.99 years with neck or chest MRI were retrospectively collected.According to the Schmeling grading method,the epiphyseal development of the clavicle MRI was divided into five grades.The consistency of methods was evaluated.The correlation and general descriptive analysis between MRI grades and age was analyzed.The sex difference was analyzed.Curve fitting was used to establish a nonlinear model between age and grades.Results The grades of clavicle MRI showed a significant age-related trend(Figure 2),and the correlation was 0.861(0.887 in males and 0.840 in females).Except for grade 1,there was no significant difference between males and females in other grades.The minimum age of male grade 3 was greater than 14 years old,and the minimum age of female grade 3 was greater than 16 years old.The minimum age in grade 4 and grade 5 was over 18 years old in both sexes.The best curve fitting model was cubic model for both sexes(R2=0.805 for men and 0.722 for women).Conclusion Clavicle MRI can be used for the assessment of bone age in Chinese population.Complete epiphyseal plate closure can be used as a reliable indicator for the determination of age at 18 years old,and it is expected to achieve radiation-free forensic bone age assessment.

OBJECTIVE To establish a method for determination cinoxate and other 30 kinds of sunscreen agents in sunscreen cosmetics by HPLC. METHODS Twenty-one fat-soluble sunscreen agents(1#−21#) were ultrasonically extracted by the mixed solution of methanol-tetrahydrofuran(1∶1), 10 kinds of water-soluble sunscreen agents(22#−31#) were ultrasonically extracted by the mixed solution of methanol-tetrahydrofuran-water(2∶3∶5) from the samples. Agilent Zorbax SB C18(4.6 mm× 250 mm, 5 μm) column was used to separate cinoxate and other fat-soluble sunscreen agents(1#−20#), Agilent Zorbax SB C18(2.1 mm× 100 mm, 3.5 μm) column was used to separate polysiloxane-15(21 #) , Waters Symmetry C18(4.6 mm× 250 mm, 5 μm) column was used to separate 10 water-soluble sunscreen agents. Methanol-isopropanol-water, isopropanol-tetrahydrofuran-water, and methanol-acetonitrile-0.02 mol·L−1 ammonium acetate solution(add phosphoric acid to adjust pH to 5.0) were used as mobile phase in gradient elution respectively. The flow rates were 1.2, 0.5, 1.0 mL·min−1. The detection wavelengths were 358nm(7 #, 11 #) , 295 nm(23#−25#, 27#−31#), 311 nm(other components). The injection volumes were 5 µL(polysiloxane-15) and 10 µL(other component), the column temperature was set at 30℃. RESULTS The linear relationships(r>0.9999) of 31 sunscreen agents were good in corresponding concentration range. The limit of detection were in the range of 0.002%−0.02%. The recoveries of two substrates at three different supplemental levels ranged from 92.4% to 110.3%, with the RSDs of 0.02%−4.5%. Forty batches of domestic and imported sunscreen cosmetics were determined by this method, 17 kinds of approved sunscreen agents were detected, of which polysiloxane-15 were detected in 10 batches of samples. By comparing with the current method in Safety and Technical Standards for Cosmetics(2015 edition) , it was found that the extraction efficiency of fat-soluble sunscreen agents was superior to the current method, the stability of drometrizole trisiloxan was improved, cinoxate, polysiloxane-15 and other 7 kinds of sunscreens were added. CONCLUSION This method is accurate, sensitive and reliable, which can be used for the detection and analysis of sunscreen in sunscreen cosmetics.

Based on the analysis of heart rate variability(HRV),a prediction method for paroxysmal atrial fibrillation(PAF)attacks is proposed.A new adaptive filtering technique is used for smoothing and coarse graining of HRV,followed by entropy-based quantification of HRV complexity at multiple adaptive scales.After the features are normalized by Min-Max,feature subsets are selected by sequential forward selection method,and then input to support vector machine to identify HRV types and predict PAF attacks.Through 5-fold cross-validation on a set of 50 HRV sequences each lasting 5 minutes,the optimal prediction results are obtained:98%accuracy,100%sensitivity,96%specificity,demonstrating excellent performance.In addition,the experiment shows significant changes(P<0.05)in the complexity eigenvalues of HRV far away from and close to PAF at different frequency bands,reflecting alterations in nervous system regulation of cardiac rhythm and a decline in the ability to adapt to external environmental changes such as stress regulation.

Presynaptic dopaminergic PET imaging is a useful method for the diagnosis of parkinsonism. Based on the expert consensus on operation and clinical application of dopamine transporter brain PET imaging technology published in 2020, this paper further recommends the relevant elements of result interpretation of presynaptic dopaminergic PET imaging.

Ureteral stents play an important role in the treatment of ureteral strictures. It supports the narrow urethra and ensures the smooth flow of urine, thus alleviating the impact of ureteral stricture on kidney function. Traditional ureteral stents are prone to complications such as stones, bacterial infections, inflammation, and restenosis when indwelling in the body. This paper reviews the performance requirements of ureteral stents, introduces ureteral stents of different structures, functions, materials, and preparation as well as processing techniques, and analyzes the key problems and future research directions of ureteral stents, which provides a reference basis for the research of ideal ureteral stents.

Objective: To investigate parent-child conflict among primary and secondary school students and their parents, and to promote family harmony and mental health of children and adolescents during the COVID-19 pandemic. Methods: An anonymous online survey was completed by 12 711 parents of primary and middle school students during mid-March, 2020. Emotional translation, coping style, parent-child conflict were collected and analyzed by grade. Results: The incidence of parent-child conflict was emotional opposition (62.3%), verbal conflict (52.6%) and physical conflict (20.5%), respectively. About 38.1% of parents and 23.6% of students experienced negative emotions, such as anxiety and anger, and the students used coping styles that were more uniform than those of their parents. About 77.9% of families reported that they experienced different levels of parent-child conflict, which was mainly caused by child learning difficulties(45.6%), daily arrangements(22.1%), and the use of electronic devices(10.2%); compared with the previous year, about 31.4% of families reported an increase in the frequency of parent-child conflicts in the last month. Conclusion Parent-child conflict is highly prevalent in the families of primary and middle school students, and such conflicts were affected by stress-related factors, which included COVID-19. It s necessary to improve the provision of relevant mental health education and psychological assistance.