1.Effect of measurement site on diagnostic performance of CT-derived fractional flow reserve
Yutao ZHOU ; Na ZHAO ; Yunqiang AN ; Lei SONG ; Chaowei MU ; Jingang CUI ; Tao JIANG ; Li XU ; Hongjie HU ; Lin LI ; Dumin LI ; Wenqiang CHEN ; Lijuan FAN ; Feng ZHANG ; Yang GAO ; Bin LYU
Chinese Journal of Radiology 2025;59(6):704-711
Objective:To investigate the effect of CT-derived fractional flow reserve (CT-FFR) measurement sites on the values and the diagnostic performance, and to determine the optimal measurement site for CT-FFR using invasive FFR as the reference standard.Methods:This study was part of the CT-FFR CHINA clinical trial. Patients with suspected coronary artery disease who were scheduled for invasive coronary angiography (ICA) were prospectively recruited from five clinical centers across the country from November 2018 to March 2020. Each enrolled patient underwent coronary CT angiography (CCTA), CT-FFR, ICA, and invasive pressure wire-based FFR assessments sequentially within one week. Four groups of CT-FFR values were obtained on each enrolled target vessels according to different CT-FFR measurement locations: 1, 2, 3 cm distal to the target lesion, and terminal vessel groups. Spearman and Bland-Altman analyses were used to explore the correlation and consistency of CT-FFR values and FFR values at different measurement sites. The measurement deviation of CT-FFR was also compared. Diagnostic accuracy and performance of CT-FFR, including sensitivity, specificity, positive predictive value, negative predictive value, and area under the receiver operating characteristic curve (AUC), in discriminating myocardial ischemia were analyzed across all measurement site groups on a per-vessel level, using FFR as the reference standard.Results:A total of 289 patients with 345 target lesion vessels were included. According to CCTA, there were 51 target vessels (14.8%) with<50% stenosis, 106 vessels (30.7%) with 50%-69% stenosis, and 188 vessels (54.5%) with stenosis≥70%. At per-vessel level, CT-FFR and FFR values at each measurement position group were highly positively correlated: 1 cm distal to target lesion group, r=0.734 ( P<0.001); 2 cm distal to target lesion group, r=0.732 ( P<0.001); 3 cm distal to target lesion group, r=0.737 ( P<0.001); terminal vessel group was 0.719 ( P<0.001). At per-vessel level, CT-FFR and FFR values of all measurement sites were in good agreement (Bland-Altman analysis results): 1 cm distal to target lesion group, 0.014 (95% LoA 0.002-0.026); 2 cm distal to target lesion group, 0.026 (95% LoA 0.015-0.038); 3 cm distal to target lesion group, 0.040 (95% LoA 0.039-0.051); terminal vessel group, 0.075 (95% LoA 0.064-0.087). And at per-vessel level, the accuracy of diagnosing myocardial ischemia with CT-FFR at 1 cm was highest [84.6% (95% CI 80.4%-88.3%)], and the lowest accuracy in the terminal vessel group [67.0% (95% CI 61.7%-72.0%)]. However, there was no significant difference in the diagnostic accuracy of CT-FFR at 1 cm, 2 cm [80.6% (95% CI 76.1%-84.6%)] and 3 cm [77.5% (95% CI 72.6%-81.7%)]. AUC of CT-FFR at 1 cm distal to the lesion were both highest for global level and moderately stenosis (50%-69%) lesions [0.85 (95% CI 0.81-0.89), 0.84 (95% CI 0.77-0.90)]. And the differences were statistically significant among the four measurement location groups (all P<0.05). Conclusions:The deviation of CT-FFR increases with measurement site distance distal to target lesions. One centimeter distal to the target lesion is the optimal measurement site, and the CT-FFR value here shows the highest diagnostic performance for myocardial ischemic lesions, especially for moderate stenosis.
2.Extracellular vesicles: Roles in oocytes and emerging therapeutic opportunities.
Zhongyu ZHAO ; Yinrui SUN ; Renhao GUO ; Junzhi LIANG ; Wanlin DAI ; Yutao JIANG ; Yafan YU ; Yuexin YU ; Lixia HE ; Da LI
Chinese Medical Journal 2025;138(9):1050-1060
The production of high-quality oocytes requires precisely orchestrated intercellular communication. Extracellular vesicles (EVs) are cell-derived nanoparticles that play a vital role in the transfer of bioactive molecules, which has gained much attention in the field of diagnosis and treatment. Over the past ten years, the participation of EVs in the reproductive processes of oocytes has been broadly studied and has shown great potential for elucidating the intricacies of female reproductive health. This review provides an extensive discussion of the influence of EVs on oocytes, emphasizing their involvement in normal physiology and altered cargo under pathological conditions. In addition, the positive impact of therapeutic EVs on oocyte quality and their role in alleviating ovarian pathological conditions are summarized.
Humans
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Extracellular Vesicles/physiology*
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Oocytes/cytology*
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Female
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Animals
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Cell Communication/physiology*
3.Pathogen characteristics and antimicrobial drug selection in periprosthetic joint infection
Weijun WANG ; Gongan JIANG ; Yuhao YANG ; Minghao ZHANG ; Yutao YANG ; Qing JIANG
Chinese Journal of Orthopaedics 2025;45(10):621-629
Objective:Periprosthetic joint infection (PJI) is one of the most severe complications following hip and knee arthroplasty and is a leading cause of revision surgery. Pathogens and their antibiotic susceptibility are key factors in the successful treatment of PJI. This study retrospectively analyzes the pathogen characteristics and antimicrobial susceptibility of PJI patients treated at our center, aiming to establish an empirical antibiotic regimen for PJI in the region, providing a reference for empirical antibiotic therapy in the clinical management of PJI.Methods:This study retrospectively reviewed PJI patients treated at our center from January 2018 to October 2024. In each case, preoperative arthrocentesis fluid, and synovium tissue from at least three sites during surgery were collected for aerobic and anaerobic blood culture. The positive culture rate, distribution of pathogens based on Gram staining, methicillin resistance, mixed infections, and multidrug resistance were analyzed. Effective coverage parameters were constructed based on antimicrobial sensitivity and coverage rates, and appropriate empirical antimicrobial regimens were proposed.Results:A total of 233 PJI patients were included in the analysis. There were 99 males and 134 females with an average age of 67.0±10.1 years (ranging from 32 to 93 years). The study included 130 hip and 103 knee arthroplasty patients. Among the patients, 202 (86.7%) had positive cultures, with a total of 301 pathogen strains isolated: 268 Gram-positive bacteria (89.4%), 25 Gram-negative bacteria (8.3%), and 7 fungal strains (2.3%). The most common Gram-positive bacteria were coagulase-negative staphylococci (196 strains, 65.1%), epidermal staphylococci (77 strains, 25.6%), Staphylococcus aureus (39 strains, 13.0%), and Streptococcus spp. (19 strains, 6.3%). The most common Gram-negative bacteria were Enterobacteriaceae (14 strains, 4.7%). In hip joint infections, the most prevalent pathogens were epidermal Staphylococci (48 strains, 28.1%) and Staphylococcus aureus (27 strains, 15.8%), while in knee joint infections, epidermal Staphylococci (29 strains, 22.3%) were most common. Regarding antibiotic resistance, 48.5% of staphylococcal strains were methicillin-resistant Staphylococcus, and 51.5% were multidrug-resistant strains. Staphylococci were 100% susceptible to vancomycin, teicoplanin, daptomycin, linezolid, and tigecycline, but exhibited high resistance to β-lactams and quinolone antibiotics. Analysis of empirical antibiotic regimens revealed that vancomycin combined with meropenem, linezolid combined with meropenem, vancomycin combined with imipenem, vancomycin combined with piperacillin/tazobactam, and vancomycin combined with ceftriaxone had effective coverage rates of 97.0%, 97.0%, 96.0%, 94.9%, and 90.9%, respectively.Conclusion:The main pathogens in PJI in this region are Gram-positive bacteria, with high rates of methicillin resistance and multidrug resistance. Based on antimicrobial susceptibility data, we recommend vancomycin combined with meropenem as the empirical treatment regimen for culture-negative PJI in this region, with linezolid combined with meropenem as an alternative.
4.Real world clinical data analysis of fuzuloparib for the treatment of ovarian epithelial cancer patients
Danhui WENG ; Jie JIANG ; Yingjie YANG ; Mingqian LU ; Jiaying BAI ; Ming LIU ; Xiaoling LI ; Jun TIAN ; Yutao GUAN ; Quan LI ; Liang CHEN ; Qiubo LYU ; Lixia MA ; Yali WANG ; Huicheng XU ; Hailong GUO ; Li SUN ; Ding MA ; Qinglei GAO
Chinese Journal of Obstetrics and Gynecology 2025;60(8):590-599
Objective:To evaluate the safety and effectiveness of fuzuloparib for the treatment of ovarian epithelial cancer patients in the real world setting.Methods:A retrospective analysis was conducted on the baseline data of 4 620 ovarian cancer patients who had received fuzuloparib monotherapy or combination therapy. Another 224 ovarian cancer patients who were willing to receive fuzuloparib monotherapy or combination therapy were prospectively enrolled, and their baseline characteristics, drug effectiveness, and safety data were analyzed.Results:(1) Among the 4 620 patients in the retrospective cohort, the median age of patients was 60 years; tumor types: 89.8% (4 149/4 620) had ovarian cancer. Among patients with clearly documented information, the vast majority had a histological type of serous carcinoma (82.9%, 3 770/4 546) and International Federation of Gynecology and Obstetrics (FIGO) staging of Ⅲ-Ⅳ (90.9%, 1 537/1 691). (2) Among the 224 patients in the prospective cohort, the median age of patients was 57 years; tumor types: 83.9% (188/224) had ovarian cancer. Among patients with clearly documented records, the predominant pathologic type was serous carcinoma (91.9%, 193/210), and FIGO stage was Ⅲ-Ⅳ in 79.9% (139/174). (3) Among the 224 prospective patients: 84 patients received first-line fluzoparib maintenance therapy, 92 patients received fluzoparib maintenance therapy after platinum-sensitive recurrence, 23 patients received direct fluzoparib treatment after platinum-sensitive recurrence, 19 patients received direct fluzoparib treatment after platinum-resistant recurrence. The median follow-up durations were 8.5, 8.7, 7.9, and 6.7 months, respectively. The median durations of fluzoparib treatment were 6.7, 4.8, 3.1, and 1.9 months, respectively. The median progression-free survival (PFS) times were not reached during follow-up, 12.6 months, not reached during follow-up, and 4.8 months, respectively. The 1-year PFS rates were 84.1%, 55.0%, 69.8%, and 45.5%, respectively. The remaining 6 patients received other fluzoparib regimens. (4) Among the 224 patients in the prospective dataset, 205 had safety data recorded. Of these, 127 patients (62.0%, 127/205) experienced treatment-related adverse events, with common events including anemia (24.4%, 50/205), thrombocytopenia (21.0%, 43/205), and leukopenia (19.5%, 40/205). Among the 205 patients, 43 (21.0%, 43/205) experienced grade 3 or higher treatment-related adverse events, with common events including anemia (8.3%, 17/205) and thrombocytopenia (8.3%, 17/205).Conclusions:The effectiveness of fuzuloparib in clinical application is generally consistent with other drugs in the same class, with good safety. This study provids new clinical evidence for the treatment of ovarian cancer with fuzuloparib.
5.Pathogen characteristics and antimicrobial drug selection in periprosthetic joint infection
Weijun WANG ; Gongan JIANG ; Yuhao YANG ; Minghao ZHANG ; Yutao YANG ; Qing JIANG
Chinese Journal of Orthopaedics 2025;45(10):621-629
Objective:Periprosthetic joint infection (PJI) is one of the most severe complications following hip and knee arthroplasty and is a leading cause of revision surgery. Pathogens and their antibiotic susceptibility are key factors in the successful treatment of PJI. This study retrospectively analyzes the pathogen characteristics and antimicrobial susceptibility of PJI patients treated at our center, aiming to establish an empirical antibiotic regimen for PJI in the region, providing a reference for empirical antibiotic therapy in the clinical management of PJI.Methods:This study retrospectively reviewed PJI patients treated at our center from January 2018 to October 2024. In each case, preoperative arthrocentesis fluid, and synovium tissue from at least three sites during surgery were collected for aerobic and anaerobic blood culture. The positive culture rate, distribution of pathogens based on Gram staining, methicillin resistance, mixed infections, and multidrug resistance were analyzed. Effective coverage parameters were constructed based on antimicrobial sensitivity and coverage rates, and appropriate empirical antimicrobial regimens were proposed.Results:A total of 233 PJI patients were included in the analysis. There were 99 males and 134 females with an average age of 67.0±10.1 years (ranging from 32 to 93 years). The study included 130 hip and 103 knee arthroplasty patients. Among the patients, 202 (86.7%) had positive cultures, with a total of 301 pathogen strains isolated: 268 Gram-positive bacteria (89.4%), 25 Gram-negative bacteria (8.3%), and 7 fungal strains (2.3%). The most common Gram-positive bacteria were coagulase-negative staphylococci (196 strains, 65.1%), epidermal staphylococci (77 strains, 25.6%), Staphylococcus aureus (39 strains, 13.0%), and Streptococcus spp. (19 strains, 6.3%). The most common Gram-negative bacteria were Enterobacteriaceae (14 strains, 4.7%). In hip joint infections, the most prevalent pathogens were epidermal Staphylococci (48 strains, 28.1%) and Staphylococcus aureus (27 strains, 15.8%), while in knee joint infections, epidermal Staphylococci (29 strains, 22.3%) were most common. Regarding antibiotic resistance, 48.5% of staphylococcal strains were methicillin-resistant Staphylococcus, and 51.5% were multidrug-resistant strains. Staphylococci were 100% susceptible to vancomycin, teicoplanin, daptomycin, linezolid, and tigecycline, but exhibited high resistance to β-lactams and quinolone antibiotics. Analysis of empirical antibiotic regimens revealed that vancomycin combined with meropenem, linezolid combined with meropenem, vancomycin combined with imipenem, vancomycin combined with piperacillin/tazobactam, and vancomycin combined with ceftriaxone had effective coverage rates of 97.0%, 97.0%, 96.0%, 94.9%, and 90.9%, respectively.Conclusion:The main pathogens in PJI in this region are Gram-positive bacteria, with high rates of methicillin resistance and multidrug resistance. Based on antimicrobial susceptibility data, we recommend vancomycin combined with meropenem as the empirical treatment regimen for culture-negative PJI in this region, with linezolid combined with meropenem as an alternative.
6.Real world clinical data analysis of fuzuloparib for the treatment of ovarian epithelial cancer patients
Danhui WENG ; Jie JIANG ; Yingjie YANG ; Mingqian LU ; Jiaying BAI ; Ming LIU ; Xiaoling LI ; Jun TIAN ; Yutao GUAN ; Quan LI ; Liang CHEN ; Qiubo LYU ; Lixia MA ; Yali WANG ; Huicheng XU ; Hailong GUO ; Li SUN ; Ding MA ; Qinglei GAO
Chinese Journal of Obstetrics and Gynecology 2025;60(8):590-599
Objective:To evaluate the safety and effectiveness of fuzuloparib for the treatment of ovarian epithelial cancer patients in the real world setting.Methods:A retrospective analysis was conducted on the baseline data of 4 620 ovarian cancer patients who had received fuzuloparib monotherapy or combination therapy. Another 224 ovarian cancer patients who were willing to receive fuzuloparib monotherapy or combination therapy were prospectively enrolled, and their baseline characteristics, drug effectiveness, and safety data were analyzed.Results:(1) Among the 4 620 patients in the retrospective cohort, the median age of patients was 60 years; tumor types: 89.8% (4 149/4 620) had ovarian cancer. Among patients with clearly documented information, the vast majority had a histological type of serous carcinoma (82.9%, 3 770/4 546) and International Federation of Gynecology and Obstetrics (FIGO) staging of Ⅲ-Ⅳ (90.9%, 1 537/1 691). (2) Among the 224 patients in the prospective cohort, the median age of patients was 57 years; tumor types: 83.9% (188/224) had ovarian cancer. Among patients with clearly documented records, the predominant pathologic type was serous carcinoma (91.9%, 193/210), and FIGO stage was Ⅲ-Ⅳ in 79.9% (139/174). (3) Among the 224 prospective patients: 84 patients received first-line fluzoparib maintenance therapy, 92 patients received fluzoparib maintenance therapy after platinum-sensitive recurrence, 23 patients received direct fluzoparib treatment after platinum-sensitive recurrence, 19 patients received direct fluzoparib treatment after platinum-resistant recurrence. The median follow-up durations were 8.5, 8.7, 7.9, and 6.7 months, respectively. The median durations of fluzoparib treatment were 6.7, 4.8, 3.1, and 1.9 months, respectively. The median progression-free survival (PFS) times were not reached during follow-up, 12.6 months, not reached during follow-up, and 4.8 months, respectively. The 1-year PFS rates were 84.1%, 55.0%, 69.8%, and 45.5%, respectively. The remaining 6 patients received other fluzoparib regimens. (4) Among the 224 patients in the prospective dataset, 205 had safety data recorded. Of these, 127 patients (62.0%, 127/205) experienced treatment-related adverse events, with common events including anemia (24.4%, 50/205), thrombocytopenia (21.0%, 43/205), and leukopenia (19.5%, 40/205). Among the 205 patients, 43 (21.0%, 43/205) experienced grade 3 or higher treatment-related adverse events, with common events including anemia (8.3%, 17/205) and thrombocytopenia (8.3%, 17/205).Conclusions:The effectiveness of fuzuloparib in clinical application is generally consistent with other drugs in the same class, with good safety. This study provids new clinical evidence for the treatment of ovarian cancer with fuzuloparib.
7.Effect of measurement site on diagnostic performance of CT-derived fractional flow reserve
Yutao ZHOU ; Na ZHAO ; Yunqiang AN ; Lei SONG ; Chaowei MU ; Jingang CUI ; Tao JIANG ; Li XU ; Hongjie HU ; Lin LI ; Dumin LI ; Wenqiang CHEN ; Lijuan FAN ; Feng ZHANG ; Yang GAO ; Bin LYU
Chinese Journal of Radiology 2025;59(6):704-711
Objective:To investigate the effect of CT-derived fractional flow reserve (CT-FFR) measurement sites on the values and the diagnostic performance, and to determine the optimal measurement site for CT-FFR using invasive FFR as the reference standard.Methods:This study was part of the CT-FFR CHINA clinical trial. Patients with suspected coronary artery disease who were scheduled for invasive coronary angiography (ICA) were prospectively recruited from five clinical centers across the country from November 2018 to March 2020. Each enrolled patient underwent coronary CT angiography (CCTA), CT-FFR, ICA, and invasive pressure wire-based FFR assessments sequentially within one week. Four groups of CT-FFR values were obtained on each enrolled target vessels according to different CT-FFR measurement locations: 1, 2, 3 cm distal to the target lesion, and terminal vessel groups. Spearman and Bland-Altman analyses were used to explore the correlation and consistency of CT-FFR values and FFR values at different measurement sites. The measurement deviation of CT-FFR was also compared. Diagnostic accuracy and performance of CT-FFR, including sensitivity, specificity, positive predictive value, negative predictive value, and area under the receiver operating characteristic curve (AUC), in discriminating myocardial ischemia were analyzed across all measurement site groups on a per-vessel level, using FFR as the reference standard.Results:A total of 289 patients with 345 target lesion vessels were included. According to CCTA, there were 51 target vessels (14.8%) with<50% stenosis, 106 vessels (30.7%) with 50%-69% stenosis, and 188 vessels (54.5%) with stenosis≥70%. At per-vessel level, CT-FFR and FFR values at each measurement position group were highly positively correlated: 1 cm distal to target lesion group, r=0.734 ( P<0.001); 2 cm distal to target lesion group, r=0.732 ( P<0.001); 3 cm distal to target lesion group, r=0.737 ( P<0.001); terminal vessel group was 0.719 ( P<0.001). At per-vessel level, CT-FFR and FFR values of all measurement sites were in good agreement (Bland-Altman analysis results): 1 cm distal to target lesion group, 0.014 (95% LoA 0.002-0.026); 2 cm distal to target lesion group, 0.026 (95% LoA 0.015-0.038); 3 cm distal to target lesion group, 0.040 (95% LoA 0.039-0.051); terminal vessel group, 0.075 (95% LoA 0.064-0.087). And at per-vessel level, the accuracy of diagnosing myocardial ischemia with CT-FFR at 1 cm was highest [84.6% (95% CI 80.4%-88.3%)], and the lowest accuracy in the terminal vessel group [67.0% (95% CI 61.7%-72.0%)]. However, there was no significant difference in the diagnostic accuracy of CT-FFR at 1 cm, 2 cm [80.6% (95% CI 76.1%-84.6%)] and 3 cm [77.5% (95% CI 72.6%-81.7%)]. AUC of CT-FFR at 1 cm distal to the lesion were both highest for global level and moderately stenosis (50%-69%) lesions [0.85 (95% CI 0.81-0.89), 0.84 (95% CI 0.77-0.90)]. And the differences were statistically significant among the four measurement location groups (all P<0.05). Conclusions:The deviation of CT-FFR increases with measurement site distance distal to target lesions. One centimeter distal to the target lesion is the optimal measurement site, and the CT-FFR value here shows the highest diagnostic performance for myocardial ischemic lesions, especially for moderate stenosis.
8.Epidemiological characteristics and toxicant type of acute poisoning cases in China, 2016-2022
Yutao ZHANG ; Shaofeng JIANG ; Nan LANG ; Jing ZHOU ; Hongshun ZHANG
Chinese Journal of Epidemiology 2024;45(10):1376-1382
Objective:To analyze the acute poison epidemic and provide evidence for developing prevention and control strategies for acute poisoning.Methods:A retrospective analysis was conducted on acute poisoning cases collected from 2016 to 2022 in a health emergency information platform for acute poisoning accidents. The cases were grouped according to the distribution of poisoning occurrence time, geographic distribution, demographic distribution, types of toxicants, poisoning causes, and outcomes. Data were organized and analyzed using Excel 2016 and R 4.2.3.Results:A total of 95 754 acute poisoning cases were included in this study. The primary toxicants were pesticides, drugs, and industrial/household chemicals, accounting for 30.4%, 22.4%, and 20.4% of the total cases, respectively. Acute poisoning occurred throughout the year, with the highest frequency from June to August, accounting for 31.9%. The seasonal distribution varied among different types of toxicants. Except for plant poisoning, which showed a bimodal distribution, the other poisonings showed an unimodal distribution. There was a strong seasonality in fungal poisoning, which peaked in July. There was an obvious seasonality in animal poisoning, with a peak in August. The proportion of biological poisonings in the southwest region was higher than in other regions, including plants, animals, and fungi. There were more females than males, and their education level was mainly junior high school and below (35.2%). The main occupation was farmers (34.2%), and the main causes of poisoning were accidents and suicides. The case fatality rate of all poisoning cases was 1.24%. Pesticide poisoning was the most common type, and chlorfenapyr (11.68%), Diquat (7.23%), and paraquat (7.05%) ranked as the top three toxicants.Conclusions:The occurrence of acute poisoning has an obvious seasonal trend, and the toxicant spectrum of different regions and populations is different. A comprehensive poisoning surveillance system can provide a better understanding of the occurrence of poisonings, and facilitate the formulation of more scientifically precise poisoning prevention and control strategies.
9.Molecular biological characteristics of the 2019 novel Coronavirus in Shijiazhuang
Huixia GAO ; Lin YANG ; Yun GUO ; Yicong WANG ; Yuzhen LIU ; Yue TANG ; Zhang HE ; Xinming LIANG ; Shunkai HUANG ; Peng GAO ; Ying HUANG ; Muwei DAI ; Zhi ZHANG ; Qian HU ; Yuling WANG ; Fang CHEN ; Erhei DAI ; Ping JIANG ; Yutao DU
Chinese Journal of Laboratory Medicine 2022;45(6):637-641
Objective:To analyze the molecular epidemiological characteristics of the Corona virus disease 2019 (COVID-19) cases in Shijiazhuang, which can reveal the origin of the outbreak and provide a scientific basis for COVID-19 prevention and control.Methods:From January 2 to January 8, 2021, a total of 404 samples from 170 COVID-19 cases were collected from the Shijiazhuang Fifth Hospital. The consensus sequence of 2019 novel Coronavirus(2019-nCoV) was obtained through multiplex polymerase chain reaction-based sequencing. The sequences of 170 COVID-19 cases were analyzed by the PANGOLIN, and the data were statistically analyzed by T-test.Results:Among the 404 COVID-19 samples, a total of 356 samples obtained high quality genome sequences (>95%,100×sequencing depth). The whole genome sequences of 170 COVID-19 cases were obtained by eliminating repeated samples. All 170 sequences were recognized as lineage B1.1 using PANGOLIN. The number of single nucleotide polymorphism arrange from 18-22 and most of the single nucleotide polymorphism were synonymous variants. All of 170 genomes could be classified into 48 sub-groups and most of the genomes were classified into 2 sub-groups (66 and 31, respectively).Conclusions:All cases in this study are likely originated from one imported case. The viruses have spread in the community for a long time and have mutated during the community transmission.
10.Comprehensive measurement and quantification of bio-mechanical properties of the temporomandibular joint disc
Nan JIANG ; Yutao YANG ; Ruiye BI ; Pinyin CAO ; Yi HOU ; Songsong ZHU
Chinese Journal of Stomatology 2021;56(8):764-768
Objective:To comprehensively investigate the biomechanical properties of the temporomandibular joint (TMJ) disc and to perfect the mechanical testing system of the TMJ disc by conducting tests of compression, tension, cyclic compression, cyclic tension, creep and friction.Methods:Fifteen fresh goat heads (weighing 2.5-3.0 kg) were purchased from the market. They were all ordinary goats (9-12 months old, body weighing 18-21 kg) regardless of gender. Bilateral articular discs (a total of 30) were dissected within 30 minutes after execution. According to the national standard for mechanical testing of viscoelastic materials, fresh TMJ disc specimens of goat were prepared and tests were carried out in physiological conditions. The universal mechanical testing machine was utilized to test biomechanical properties of TMJ discs.Results:The compressive modulus of TMJ discs was (8.41±2.12) MPa and the tensile modulus was (9.54± 3.26) MPa. The mechanical characteristics would be irreversibly altered once the load exceeded the physiological range. In addition, it underwent apparent creep relaxation under continuous strain (0.5 MPa or 3.0 MPa) and the surface friction coefficient of the TMJ discs (0.015+0.011) was much lower than that of general viscoelastic materials.Conclusions:The TMJ disc was a bio-viscoelastic structure with excellent tensile and compressive properties and its surface was extremely smooth in wet conditions.

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