Objective:To explore the effects of the immune responses mediated by topological structures of three-dimensional bioprinted scaffolds on hair follicle cycle in mice.Methods:The study was an experimental research. The alginate-gelatin composite hydrogels were printed into scaffolds using a three-dimensional bioprinter and named T45 scaffolds, T60 scaffolds, and T90 scaffolds according to the 3 topological structures of the scaffolds (the rotation angles of the printhead during printing were 45°, 60°, and 90°, respectively), and the morphology of the three scaffolds was observed after cross-linking by naked eyes. Nine 8-week-old female C57BL/6J mice were divided into T45 group, T60 group, and T90 group, according to the random number table, with three mice in each group, and the T45, T60, and T90 scaffolds were subcutaneously implanted on the back of mice, respectively. On post implantation day (PID) 7, the hair growth in the dorsal depilated area of mice was observed, the thickness of the fiber capsule around the scaffolds was observed by hematoxylin-eosin staining, and the expression levels of CD68, bone morphogenetic protein-2 (BMP-2), and tumor necrosis factor (TNF) protein in the tissue surrounding the scaffolds were observed by immunofluorescence staining. The samples of the above experiments were all 3.Results:The topological structures of the three scaffolds were all clear with high fidelity after cross-linking. On PID 7, the hair growth was obvious in the dorsal depilated area of mice in T45 group and T90 group, while hair growth was slow in the scaffold implantation area of mice in T60 group, which was significantly different from that of the unimplanted area. On PID 7, compared with (18±4) μm in T90 group, the thickness of both the fiber capsule around the scaffolds ((39±4) and (55±8) μm) of mice in T45 group and T60 group was significantly increased ( P<0.05); the thickness of the fiber capsule around the scaffolds of mice in T60 group was also significantly increased compared with that in T45 group ( P<0.05). On PID 7, the expression level of CD68 protein in the tissue surrounding the scaffolds of mice in T60 group was significantly higher than the levels in T45 group and T90 group (with both P values <0.05). The expression level of BMP-2 protein in the tissue surrounding the scaffolds of mice in T60 group was significantly higher than the levels in T45 group and T90 group (with both P values <0.05), and the expression level of BMP-2 protein in the tissue surrounding the scaffolds of mice in T45 group was significantly higher than that in T90 group ( P<0.05). The expression level of TNF protein in the tissue surrounding the scaffolds of mice in T60 group was significantly lower than the levels in T45 group and T90 group (with both P values <0.05). Conclusions:Three-dimensional bioprinted scaffolds with different topological structures mediate different degrees of immune responses after being implanted in mice. A moderate immune response promotes hair growth in depilated area of mice, while an excessive immune response results inhibits the hair follicle entering into the anagen phase.

Objective:Based on the specific cleavage and non-specific "trans-cleavage" activities of the clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein(CRISPR/Cas13), we established a visually amplification-free rapid detection technique of 2019-nCoV nucleic acid. This technique is easily processed with a low detection limit and good specificity.Methods:According to the 2019-nCoV gene sequence, specific CRISPR RNAs were screened and designed by bioinformatics analysis, and then synthesized as universal signal-strained RNA transcription targets in vitro to establish and optimize the reaction system. Moreover, the 2019-nCoV pseudoviral nucleic acid was used as a standard substance to evaluate the detection limit. A total of 65 positive samples were collected from various 2019-nCoV variants, while 48 negative samples included other clinically common respiratory pathogens, such as influenza A virus, influenza B virus, human parainfluenza virus, Klebsiella pneumonia, etc. All samples were tested by quantitative PCR (qPCR), digital PCR, and the method established in this study. The sensitivity and specificity of the newly established method were analyzed and evaluated. Results:With the newly established technique, the detection time for 2019-nCoV nucleic acid could be minimized to 6 minutes. In addition, the detection limit was 14 copies/μl when assisted by the displaying instrument, whereas it increased to 28 copies/μl with the naked eye. This technique had a sensitivity and specificity of 98.5% (66/67) and 100% (46/46) respectively, showing no statistically significant difference compared to the gold standard qPCR( P=1). Conclusions:This study has successfully established a CRISPR/Cas13a-based visually rapid detection technique for 2019-nCoV nucleic acid. This technique offers the advantages of a simple process, convenient operation, low environmental operating requirements, a detection limit close to qPCR, and a strong potential for on-site testing applications.

New drug discovery is under growing pressure to satisfy the demand from a wide range of domains, especially from the pharmaceutical industry and healthcare services. Assessment of drug efficacy and safety prior to human clinical trials is a crucial part of drug development, which deserves greater emphasis to reduce the cost and time in drug discovery. Recent advances in microfabrication and tissue engineering have given rise to organ-on-a-chip, an in vitro model capable of recapitulating human organ functions in vivo and providing insight into disease pathophysiology, which offers a potential alternative to animal models for more efficient pre-clinical screening of drug candidates. In this review, we first give a snapshot of general considerations for organ-on-a-chip device design. Then, we comprehensively review the recent advances in organ-on-a-chip for drug screening. Finally, we summarize some key challenges of the progress in this field and discuss future prospects of organ-on-a-chip development. Overall, this review highlights the new avenue that organ-on-a-chip opens for drug development, therapeutic innovation, and precision medicine.

Objective:To compare the efficacy of standardized incision and conventional incision for reduction and internal fixation of multiple rib fracture.Methods:A retrospective cohort study was conducted to analyze the clinical data of 192 patients with multiple rib fracture treated in 909th Hospital of Joint Logistics Support Force (Affiliated Dongnan Hospital of Xianmen University Medical College) from January 2020 to January 2022. There were 101 males and 91 females; aged 32-94 years [(51.5±16.6)years]. The patients underwent open reduction and internal fixation with nickel-titanium shape memory alloy embracer via standard incision such as anterior axillary longitudinal incision (standard incision group, n=96) or conventional incision such as posterolateral incision (conventional incision group, n=96). The incision length, operation time, intraoperative blood loss, number of fixed fractures, indwelling time of closed thoracic drainage tube, postoperative thoracic drainage volume, postoperative spontaneous ambulation time and length of hospital stay were compared in the two groups. The visual analogue scale (VAS) was used to evaluate pain at 1 month after operation. Postoperative complications were recorded. Results:All patients were followed up for 1-16 months [4.0(3.0, 10.5)months]. The operation time, intraoperative blood loss, indwelling time of closed thoracic drainage tube, postoperative thoracic drainage volume, postoperative spontaneous ambulation time, length of hospital stay and VAS at postoperative 1 month in standard incision group [(12.1±1.6)cm, (51.4±13.0)minutes, (191.5±16.8)ml, (2.8±0.6)days, (568.9±109.0)ml, (4.1±0.7)days, (11.4±1.7)days, (2.5±0.7)points] were better than those in conventional incision group [(13.7±1.9)cm, (62.0±8.8)minutes, (248.9±65.4)ml, (4.8±1.1)days, (655.9±121.9)ml, (5.2±0.9)days, (15.3± 1.7)days, (3.5±0.7)points] ( P<0.05 or 0.01). There was no statistical difference in the number of fixed fractures between standard incision group and conventional incision group (5.1±0.8 vs. 5.4±0.9) ( P>0.05). In standard incision group, there were 3 patients with poor wound healing, 5 with pulmonary infection, 3 with atelectasis and 3 with small pleural effusion. In conventional incision group, there were 11 patients with poor wound healing, 9 with pulmonary infection, 7 with atelectasis and 7 with small pleural effusion. The incidence of postoperative complications was 14.6% (14/96) in standard incision group and 35.4% (34/96) in conventional incision group ( P<0.01). Conclusion:For multiple rib fracture, standard incision is superior to conventional incision reduction in shortening the incision length, operation time, indwelling time of drainage tube, postoperative spontaneous ambulation time and length of hospital stay, reducing the intraoperative blood loss and postoperative thoracic drainage volume, alleviating the pain and reducing the postoperative complications.

Objective:To compare the long-term efficacy of two-level cervical artificial disc replacement (CADR) and anterior cervical decompression and fusion (ACDF) in the treatment of cervical degenerative diseases.Methods:A retrospective analysis was performed on patients who had received two-level anterior cervical surgery for cervical degenerative diseases for more than 15 years from December 2003 to December 2007. The patients were divided into two groups: CADR and ACDF according to surgical methods. There were 15 patients in the CADR group, including 7 males and 8 females, with an average age of 49.73±10.26 (range, 32-70) years. Three cases of mixed cervical spondylosis, 5 cases of cervical spondylotic radiculopathy, 7 cases of cervical spondylotic myelopathy, including C 3, 4 and C 4, 5 level 1 case, C 3, 4 and C 5, 6 level 2 cases, C 4, 5 and C 5, 6 level 7 cases, C 5, 6 and C 6, 7 level 5 cases, operative segment range of motion (ROM) was 9.10°±4.00°. The follow-up time in the CADR group was 189.07±13.51 (range, 162-210) months. There were 20 patients in the ACDF group, including 12 males and 8 females, with an average age of 52.60±8.83 (range, 32-68) years. Two cases of mixed cervical spondylosis, 3 cases of cervical spondylotic radiculopathy, 15 cases of cervical spondylotic myelopathy, including C 3, 4 and C 4, 5 level 1 case, C 4, 5 and C 5, 6 level 15 cases, C 5, 6 and C 6, 7 level 4 cases, the ROM of the surgical segment was 8.31±5.23°. The mean follow-up time of ACDF group was 184.20±21.39 (range, 156-222) months. The Japanese Orthopaedic Association (JOA) score and neck disability index (NDI) were evaluated preoperatively and at the last follow-up. The overall ROM of the cervical spine, ROM of the surgical segment, and Miyazaki grading of the adjacent intervertebral disc, Odom score and complications of the two groups were evaluated at the last follow-up. Results:In the CADR group, the JOA score improved from 13.20±2.64 preoperatively to 15.93±1.22 at last follow-up, and NDI improved from 27.60%±6.44% preoperatively to 15.07%±9.71% at last follow-up, JOA improvement rate was 59.44%±60.86%, and NDI decreased by 12.53%±9.64%. In the ACDF group, JOA score improved from 12.93±2.46 preoperatively to 15.65±1.25 at last follow-up, NDI improved from 30.80%±8.11% preoperatively to 12.80%±6.31% at last follow-up, JOA improvement rate was 60.51%±43.17%, NDI decreased by 18.00%±8.34%. There was no significant difference in JOA and NDI between the two groups before surgery and at the last follow-up. At the last follow-up, the overall ROM of the cervical spine in the CADR group was 38.33°±12.31°, the ROM of the surgical segment was 6.51°±4.61°, and the overall ROM of the cervical spine in the ACDF group was 31.11°±8.65°, the ROM of the surgical segment was 0°. There was a significant difference in the overall ROM of the cervical spine between the two groups at the last follow-up ( t=7.22, P=0.049). The incidence of increased Miyazaki grading of the upper and lower adjacent segment of the cervical intervertebral disc in the CADR group were 40% and 47%, and the rate of new intervertebral disc herniation were 20% and 13%. The incidence of increased Miyazaki grading of the upper and lower adjacent segment of the cervical intervertebral disc in the ACDF group were 45% and 50%, and the incidence of new herniated disc were 25% and 40%, there is a significant difference in the degeneration rate of the lower adjacent segments between the two groups (χ 2=4.38, P=0.036). At the last follow-up, the excellent and good rate of Odom in the CADR group was 80%, and 1 case was revised; the excellent and good rate of Odom in the ACDF group was 85%, and 1 case was revised. There was no significant difference in the overall efficacy between the two groups. Conclusion:The long-term clinical efficacy of two-level CADR is comparable to that of traditional ACDF, and it preserved the ROM of the surgical segment, and is superior to ACDF in terms of the overall cervical spine ROM, and the incidence of adjacent segment degeneration.

Objective: To investigate the status and trend of low vision of junior and senior high school students in Beijing from 2009 to 2018, and to provide evidence for myopia prevention. Methods: Data came from the results of physical examination of eyesight in 2009-2018 in Beijing, which were cdlected among juncor and senior high school students in March every year. Detection rate of low vision of students and the difference across different districts and counties were analyzed. Results: From 2009 to 2018, the rate of low vision of high school and college entrance examination students in Beijing was on the rise, with the average rate of low vision of 86.07% and 76.36% respectively. Similar trend was found in the rate of high myopia(16.39% and 18.64%,respectively), while that of light and medium myopia tends to be stable. The highest rate of low vision among junior middle school students was in Xicheng (84.75%) District and Chaoyang District (84.03%), and for high middle school students,the highest rate of myopia was found in Fengtai District (91.17%) and Dongcheng District (89.92%). Conclusion In Beijing, the detection rate of low vision of middle school and college entrance examination students increased steadily, especially the high myopia. The health education of eyesight protection is of great significance to students. It is necessary to strengthen the extensive intervention of eyesight protection in middle and college entrance examination students.

Objective: To understand the awareness of sexual knowledge among primary and secondary school students, as well as their attitudes towards school sex education and to provide a reference for school-based sex education. Methods: A total of 5 531 primary and secondary school students were selected from Beijing, Chongqing, Heilongjiang (Harbin and Jiamusi) and Hubei (Wuhan and Xiaogan) by stratified cluster sampling and were investigated with self-reported questionnaire. Results: Sex-related knowledge scored 62.33±19.35, with a pass rate of 61.9%, and the excellent rate 17.5%. Sexual knowledge of junior high school students scored 64.30±19.07, with the pass rate of 64.7%, and the excellent rate 22.0%. A large proportion of primary students reported unaware of pubertal growth and HIV/AIDS-related knowledge, and a large proportion of junior high students unaware of reproductive physiology. Multivariate Logistic regression analysis showed region, grade, gender, and suburban areas were related to the level of sexual knowledge(P<0.05). More than 76.0% primary students and 85.9% middle school students agreed on the importance of school sexuality education. 59.7% of primary school students and 73.3% of junior high school students hoped to include school sexuality education in compulsory education courses; 59.8% of primary school students and 68.3% of junior high school students felt that school sexuality education should be equipped with specialized teachers. Conclusion Chinese primary and secondary school students are lack of sexual knowledge. As students have strong wills to get more information on sexual knowledge, schools should provide them with more comprehensive and effective sex education through appropriate courses and activities.

Objective: The purpose of this study was to describe the status quo and related factors on low vision (LV) among students of Beijing. Methods: All the students in Beijing were included as the subjects of interest, based on the reference of the Chinese National Survey on Students’ Constitution and Health. Results: The overall rate of LV among students in Beijing was 58.6% in 2017, with 61.6% in females, higher than 55.9% in males. LV also appeared higher in urban than in rural areas. The rates of LV appeared as 46.8%, 78.0%, 89.0%, 71.0%, in students from primary, middle, high or vocational high schools, respectively. Rates on light, moderate or severe LV were 8.4%, 17.8% and 32.5%, respectively. Conclusions The overall rate of LV among students in Beijing was considered high. Students in preschool, in 4-6 grades and the 2^nd grade of middle schools, were at the key stages of developing vision-related problems. Factors as heavy load on homework, lack of outdoor activities and 'limit of vision space’ as well as incorrect reading behavior during puberty, need to be of concern.

Objective: To understand the needs of primary and secondary school students, parents and teachers for comprehensive sexuality education content, and to explore the applicability of comprehensive sexuality education content in China. Methods: By using the method of stratified cluster sampling, 5 571 primary and middle school students and 4 835 parents from Beijing, Chongqing, Heilongjiang (Harbin and Jiamusi) and Hubei (Wuhan and Xiaogan) were selected for questionnaire survey. Depending on the physical health monitoring points of various provinces and cities, 176 sexuality education related teachers in nine regions were surveyed. The development of the questionnaire was based on the content framework of comprehensive sexuality education proposed in the International Technical Guidelines for Sexuality Education. Results: Students had a higher demand for knowledge on the concepts of "relationship" (53.4% for primary school students, 57.6% for junior high school students) and "health and well-being skills" (71.1% for primary school students, 55.9% for junior high school students). Parents had higher demand for most comprehensive sexuality education content with the exception of lower need for "sex and sexual behavior (74.7% of primary school parents, 80.8% of junior high school parents)" and "sexual and reproductive health (primary parents 74.3%, junior high school parents 75.8%)". Teachers had a high demand for most comprehensive sexuality education content, but primary school teachers had a lower need for "values, rights, culture and sex(65.9%)", "sex and sexuality(60.1%)" and "sexual and reproductive health(66.8%)". The results of correspondence analysis showed that junior middle school teachers had the highest demand for comprehensive education content, followed by primary school parents, junior middle school parents, primary school teachers, junior middle school students and primary school students. Conclusion Teachers and parents have a higher demand for most comprehensive sexuality education content, while lower demand for some relatively sensitive content. Students have a relatively low demand for comprehensive sexuality education content. It is recommended to further improve the content of school sexuality education based on the actual needs of China.

Objective To evaluate the feasibility and efficacy of twin grasper combined with endoloops on closing acute stomach perforation.Methods Two experimental porcines of stomach perforation underwent endoscopic closure by twin grasper combined with endoloops.Survival conditions and closure of perforating were observed.Results Mild infection and abdominal adhesions were observed in one week after operation.The nylon rope fell off and an ulcer-like lesion was presented in the closed position.The methylene blue leak test was negative.Histologic examination revealed chronic inflammatory cells infiltration,granulation,fibroplasias,and regenerative mucous membrane crawling toward the center of perforation.Conclusion The technique of twin grasper combined with nylon ropes in closing the acute stomach perforation is feasible and effective.