BACKGROUND:Orthodontic treatment to move the mandibular second molar in place of the missing first molar is a good method for preserving natural teeth.However,molars often exhibit mesial tipping when using clear aligners.The impact of attachments and overcorrection on the molar mesialization with clear aligners is unclear.OBJECTIVE:To investigate the effects of attachments and overcorrection on displacement and biomechanics of the mandibular second molar mesialization.METHODS:A finite element model with the left mandibular first molar missing was constructed using a volunteer's cone-beam CT and intraoral scan data.The experiment was divided into four groups based on the position of attachments on the left mandibular second molar:without attachment,buccal attachment,lingual attachment,and buccal-lingual attachment,with overcorrection degrees(0°,1°,2°,3°,and 4°)for each group,totaling 20 models.The calculation and analysis of the displacement trends and stress were performed using Abaqus software.RESULTS AND CONCLUSION:(1)Mesial tipping and intrusion of the molar,distal tipping of the canines and permolars,and linguaing of the incisors occurred during molar mesialization.(2)The displacement of molars increased when attachments were used,with the maximum displacement occurring when buccal-lingual attachments were applied.Molars tended to tip towards the side without attachments when attachments were designed unilaterally.However,the inclination of molars did not decrease when attachments were used.(3)Molars exhibited reduced mesial tipping and intrusion,approaching overall movement,and the stress of periodontal ligament was relieved and more evenly distributed during overcorrection treatment,and this effect became more pronounced with increased degrees of overcorrection.(4)Attachments can enhance the effectiveness of overcorrection,with the best performance observed when buccal-lingual attachments are used.Using attachments and overcorrection together helps control molar mesial tipping and intrusion,but overall molar movement is not achieved.

BACKGROUND:Orthodontic treatment to move the mandibular second molar in place of the missing first molar is a good method for preserving natural teeth.However,molars often exhibit mesial tipping when using clear aligners.The impact of attachments and overcorrection on the molar mesialization with clear aligners is unclear.OBJECTIVE:To investigate the effects of attachments and overcorrection on displacement and biomechanics of the mandibular second molar mesialization.METHODS:A finite element model with the left mandibular first molar missing was constructed using a volunteer's cone-beam CT and intraoral scan data.The experiment was divided into four groups based on the position of attachments on the left mandibular second molar:without attachment,buccal attachment,lingual attachment,and buccal-lingual attachment,with overcorrection degrees(0°,1°,2°,3°,and 4°)for each group,totaling 20 models.The calculation and analysis of the displacement trends and stress were performed using Abaqus software.RESULTS AND CONCLUSION:(1)Mesial tipping and intrusion of the molar,distal tipping of the canines and permolars,and linguaing of the incisors occurred during molar mesialization.(2)The displacement of molars increased when attachments were used,with the maximum displacement occurring when buccal-lingual attachments were applied.Molars tended to tip towards the side without attachments when attachments were designed unilaterally.However,the inclination of molars did not decrease when attachments were used.(3)Molars exhibited reduced mesial tipping and intrusion,approaching overall movement,and the stress of periodontal ligament was relieved and more evenly distributed during overcorrection treatment,and this effect became more pronounced with increased degrees of overcorrection.(4)Attachments can enhance the effectiveness of overcorrection,with the best performance observed when buccal-lingual attachments are used.Using attachments and overcorrection together helps control molar mesial tipping and intrusion,but overall molar movement is not achieved.

OBJECTIVE To evaluate the value of matrix-assisted laser desorption ionization time-of-flight-mass spectrometry(MALDI-TOF MS)in direct identification of carbapenem-resistant Escherichia coli and Klebsiella pneumoniae positive for blood culture.METHODS The blood culture bottles that were positive for E.coli or K.pneumoniae were collected from the patients with bloodstream infection who were treated in Zhongshan Hospi-tal,Fudan University from Jul.2021 to Jun.2023.The isolates were collected by using a gel-contact clotting tube,then the tested strains were respectively mixed with 4 μg/ml of imipenem,4 μg/ml of meropenem and 2 μg/ml of ertapenem for coculture and were incubated at 35 ℃ for 4 and 5 hours,finally,the strains were i-dentified by using the mass spectrum.The minimum inhibitory concentrations(MICs)of the three types of drugs were tested by microbroth dilution method and were set as the golden standards for the test.RESULTS Totally 31 strains of E.coli and 28 strains of K.pneumoniae that were positive in blood culture bottles were collected,both of the effective rates of controlled growth of the E.coli strains were 100.00％after the incuba-tion for 4 and 5 hours,and the effective rates of controlled growth of the K.pneumoniae strains were 9 6.43％and 100.00％after the incubation for 4 and hours,respectively.The sensitivity,specificity,positive predictive value and negative predictive value of the K.pneumoniae strains against the three types of drugs were 100.00％after the incubation for 5 hours.The specificity and positive predictive value of the E.coli strains against imipenem,meropenem and ertapenem were 100.00％after the incubation for 5 hours;the sensitivities were 73.58％,78.93％and 78.93％,respectively;the negative predictive values were 70.60％,75.00％and 75.00％,respectively.CONCLUSIONS MALDI-TOF MS is rapid and accurate for direct identification of the carbapenem-resistant E.coli and K.pneumoniae strains positive in blood culture bottles,and the accuracy reaches at 100.00％for the test of drug-resistant K.pneumoniae strains after the incubation for 5 hours.The method may provide evidence for clinical treatment of bloodstream infections induced by carbapenem-resistant Enterobacteriaceae.

Objective To evaluate the impact of setting a 4-day incubation time on the detection performance of bloodstream infection(BSI)pathogens by the BacTALERT VIRTUO blood culture system(VIRTUO).Methods Retrospectively collecting blood culture(BC)results from Zhongshan Hospital,Fudan University,from June 2021 to December 2023,and comparing the time-to-detection for clinically significant microorganisms.Results A total of 87 052 BC bottles were collected,of which 7 167(8.23%)were positive.95%of aerobic and anaerobic bottles were reported positive at 65.67 h and 91.2 h respectively.The average(median)time-to-detection for Staphylococcus aureus(S.aureus)was 21.76(16.08)h,Klebsiella pneumoniae(KP)was 15.32(11.65)h,Escherichia coli(E.coli)was 16.14(10.87)h,and Candida species was 35.2(28.5)h.Only 213 bottles(0.24%)were reported positive after 4 days of incubation;among them,88 bottles(41.31%)cultured Propionibacterium acnes(P.acnse).Medical chart reviews for BC reported positive after 96 h(4 days)showed no clinical significance.Simulated growth experiments were conducted on 11 fastidious bacteria,and the median detection time was only 10.8 h,indicating that an incubation time of 4 days is sufficient for fastidious bacteria.Conclusion A 4-day incubation is adequate for VIRTUO system.Reporting 1 day earlier to the doctors can reduce the positive rate of contaminants and the use of antimicrobial agents.

Objective To evaluate the impact of setting a 4-day incubation time on the detection performance of bloodstream infection(BSI)pathogens by the BacTALERT VIRTUO blood culture system(VIRTUO).Methods Retrospectively collecting blood culture(BC)results from Zhongshan Hospital,Fudan University,from June 2021 to December 2023,and comparing the time-to-detection for clinically significant microorganisms.Results A total of 87 052 BC bottles were collected,of which 7 167(8.23%)were positive.95%of aerobic and anaerobic bottles were reported positive at 65.67 h and 91.2 h respectively.The average(median)time-to-detection for Staphylococcus aureus(S.aureus)was 21.76(16.08)h,Klebsiella pneumoniae(KP)was 15.32(11.65)h,Escherichia coli(E.coli)was 16.14(10.87)h,and Candida species was 35.2(28.5)h.Only 213 bottles(0.24%)were reported positive after 4 days of incubation;among them,88 bottles(41.31%)cultured Propionibacterium acnes(P.acnse).Medical chart reviews for BC reported positive after 96 h(4 days)showed no clinical significance.Simulated growth experiments were conducted on 11 fastidious bacteria,and the median detection time was only 10.8 h,indicating that an incubation time of 4 days is sufficient for fastidious bacteria.Conclusion A 4-day incubation is adequate for VIRTUO system.Reporting 1 day earlier to the doctors can reduce the positive rate of contaminants and the use of antimicrobial agents.

Objective: To understand the subjective and objective comfort evaluations of students from different age groups on desks and chairs, so as to provide reference for standardized allocation and use of desks and chairs. Methods: From January to April 2024, a total of 2 446 students were selected from 26 schools in 13 districts (counties/cities) in Shanghai, Tianjin, and Wuxi from Jiangsu Province by using cluster random method, including students in kindergartens, primary schools, junior high schools,senior high schools, colleges and universities. Standardized procedures were used to measure the height and weight of participants, and the matching desks and chairs models were selected according to the height. The subjective comfort of students on matching desks and chairs was investigated, and their objective comfort was evaluated by using a self designed questionnaire. The χ 2 test was used to analyze the differences of subjective perception and objective evaluation in comfort between different types of desks and chairs. Results: About 84.1% of the students subjectively thought that large desks and small chairs were very comfortable or relatively comfortable, followed by large desks and chairs (75.7%), and the proportion of small desks and chairs was the lowest among the three types (46.2%), and the difference was statistically significant ( χ 2=722.46, P <0.01). The reporting rates of primary school, junior high school and senior high school students who subjectively considered large desks and chairs to be very comfortable/relatively comfortable were higher than that of other types of desks and chairs, and the differences were statistically significant ( χ 2=297.49, 252.82, 343.67, P <0.01). However, there was no significant difference in the subjective comfort evaluation of different types of desks and chairs among kindergarten children ( χ 2=3.21, P >0.05), and 66.3% of the students in colleges and universities felt very comfortable/relatively comfortable when they used the matching standard desks and chairs. The objective evaluation results of the comfort for the three types of desks and chairs were consistent with the subjective evaluation, but the proportions of the objective evaluation as very comfortable/relatively comfortable were higher than that of the subjective evaluation ( χ 2=20.76- 813.47, P <0.01). Conclusions Large desks and chairs, as well as large desks with small chairs are perceived comfortable, while small desks and chairs are perceived less comfortable. It is recommended to match the large desks and chairs or large desks and small chairs that are suitable for them according to the "standard", to promote physical and mental health of students.

Objective: To investigate the differences in the comfort of desks and chairs furniture among students with different body types according to the standard, so as to provide a reference for guiding students with overweight and obesity to choose the correct study furniture and revising the standards. Methods: From January to April 2024, 2 443 students from 26 schools in 13 districts (counties/cities) in Shanghai, Tianjin, and Jiangsu Province were selected by the cluster random sampling method to conduct physical examination. The subjective and objective evaluations of the comfort of height matched desks and chairs were investigated. The students were divided into non overweight, overweight, and obesity groups according to relevant criteria, and stratified analysis was performed. The χ 2 test was used to analyze differences in the comfort evaluations of desks and chairs among students with different body types. Results: Among the 2 443 students surveyed, 16.7% and 12.6% were respectively classified as overweight and obese. All students assigned the highest comfort ratings to large desks and small chairs (84.1%), and consistency was observed between students subjective and objective evaluations. The reporting rate of samll desks and chairs of obesity students subjective evaluation was lower (36.8%) than that of overweight and non overweight/obesity students (52.1%, 48.0%) ( χ 2=14.63, P <0.01). The overweight and obese group of primary school students had a worse evaluation of the comfort of large desks and chairs and small desks and chairs than those of the non overweight and obese groups( χ 2=15.78, 7.63, P <0.05). Among high school students, the overweight and obese group had worse evaluation of the comfort of large desks and chairs, as well as large desks and small chairs, than those of the non-overweight and obese groups( χ 2=9.62, 11.77, P <0.05). The objective evaluations revealed low compliance ratings on the posture of the thighs and calves for naturally forming an angle greater than 90° (55.6%), and headroom height under the table (50.3%) with small desks and chairs ( χ 2=94.05, 166.47, P <0.05). Conclusions Compared with non overweight/obese students, students with overweight and obese students report poor comfort evaluations of height matched desks and chairs. Revision of the standard should consider the body types of students, and evaluations of the comfort of desks and chairs furniture by students with overweight and obesity should be improved.

OBJECTIVE To evaluate the value of matrix-assisted laser desorption ionization time-of-flight-mass spectrometry(MALDI-TOF MS)in direct identification of carbapenem-resistant Escherichia coli and Klebsiella pneumoniae positive for blood culture.METHODS The blood culture bottles that were positive for E.coli or K.pneumoniae were collected from the patients with bloodstream infection who were treated in Zhongshan Hospi-tal,Fudan University from Jul.2021 to Jun.2023.The isolates were collected by using a gel-contact clotting tube,then the tested strains were respectively mixed with 4 μg/ml of imipenem,4 μg/ml of meropenem and 2 μg/ml of ertapenem for coculture and were incubated at 35 ℃ for 4 and 5 hours,finally,the strains were i-dentified by using the mass spectrum.The minimum inhibitory concentrations(MICs)of the three types of drugs were tested by microbroth dilution method and were set as the golden standards for the test.RESULTS Totally 31 strains of E.coli and 28 strains of K.pneumoniae that were positive in blood culture bottles were collected,both of the effective rates of controlled growth of the E.coli strains were 100.00％after the incuba-tion for 4 and 5 hours,and the effective rates of controlled growth of the K.pneumoniae strains were 9 6.43％and 100.00％after the incubation for 4 and hours,respectively.The sensitivity,specificity,positive predictive value and negative predictive value of the K.pneumoniae strains against the three types of drugs were 100.00％after the incubation for 5 hours.The specificity and positive predictive value of the E.coli strains against imipenem,meropenem and ertapenem were 100.00％after the incubation for 5 hours;the sensitivities were 73.58％,78.93％and 78.93％,respectively;the negative predictive values were 70.60％,75.00％and 75.00％,respectively.CONCLUSIONS MALDI-TOF MS is rapid and accurate for direct identification of the carbapenem-resistant E.coli and K.pneumoniae strains positive in blood culture bottles,and the accuracy reaches at 100.00％for the test of drug-resistant K.pneumoniae strains after the incubation for 5 hours.The method may provide evidence for clinical treatment of bloodstream infections induced by carbapenem-resistant Enterobacteriaceae.

Objective:To investigate the clinical and pathological characteristics of primary thoracic synovial sarcoma (PTSS).Methods:Forty-two PTSS cases diagnosed at the Department of Pathology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China from October 2011 to April 2024 were analyzed. All cases were retrospectively studied using hematoxylin-eosin staining and immunohistochemistry. Their clinicopathological features were also reviewed. SS18 rearrangement was assessed in 28 cases using fluorescence in situ hybridization (FISH). Next generation sequencing (NGS) was performed on 8 cases.Results:Among the 42 cases, there were 23 biopsies and 19 surgically-removed specimens. One case was a specimen resected after neoadjuvant chemotherapy. There were 22 males and 20 females, with an age ranging from 6 to 68 years. Twenty-nine cases occured in the lung, 6 in mediastinum, 4 in pericardium, 1 in visceral pleura, and 1 in right atrium. One case did not show any unequivocal primary site. Computed tomography showed the tumors were manifested as a cystic mass, a solid mass, or thickening of the pleura and pericardium. Thirty-two cases had respiratory symptoms, while 19 had pleural effusion. One case had a history of radiotherapy for papillary thyroid carcinoma. Nineteen patients were treated with surgery, while 19 were treated with chemotherapy without surgery. Four patients were diagnosed and discharged, without specific treatment on the record. Morphologically, 1 case was biphasic type, 39 cases were monophasic type, and 2 cases were poorly differentiated type. In addition to the typical morphology of synovial sarcoma, tumors also showed pulmonary bullous changes, stromal collagen hyalinization, hemangiopericytoma-like vasculature, stromal edematous myxoid changes, and microcystic structure. Immunohistochemically, all cases were diffusely positive for TRPS1 (22/22), TLE1 (21/22), CD99 (26/26), SS18-SSX (25/25) and INI1 (12/12), including 3 cases with decreased expression of INI1. Twenty-one cases were focally positive for EMA (21/30), 4 cases for SMA (4/23), 2 cases for S-100 (2/28), and 2 cases (2/35) for CKpan. Twenty-eight cases (28/28) had SS18 rearrangement displaying a split signal on FISH analysis. Eight cases were found to have mutations in SMC1A, NOTCH2, CDK12, SPRY4, BRCA1, STK11, NF2, and PDGFRα genes using NGS. Eighteen of the 29 patients survived and 16 showed disease progression.Conclusions:PTSS is more commonly found in the lungs than other sites and has non-classical morphological features of various types, which need to be differentiated from other tumors. TRPS1 is highly expressed in PTSS and has certain diagnostic values. The diagnosis of PTSS also requires combination of patient′s medical history with thorough imaging studies.

Objective:To explore the clinicopathological and molecular genetic characteristics of anaplastic lymphoma kinase (ALK)-rearranged renal cell carcinoma (RCC), including a rare case with the TPM1-ALK gene subtype.Methods:Three cases of ALK-rearranged RCC diagnosed in the Department of Pathology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China from January 2020 to December 2024 were collected. Their clinical pathological and next-generation sequencing (NGS) data were analyzed. Relevant literature was also reviewed, and follow-ups were carried out.Results:Among the three patients, there were 1 female (case 1) and 2 males (cases 2 and 3), with the ages of 29,41 and 44 years, respectively. All of them were presented with space-occupying renal lesions. Case 1 (KIAA1217-ALK RCC) showed mixed cystic and solid components under the microscope, with tubular, papillary, and cribriform arrangements. The tumor cells had clear boundaries, and were cubic or low columnar, arranged in a single layer, pseudostratified or in sheets. The cytoplasm was abundant and eosinophilic, and part of the cytoplasm was vacuolated, as if there was accumulation of mucoid substances. The tumor cell nuclei were oval with prominent nucleoli. A large amount of mucus and inflammatory cell infiltration were noted in the stroma. Case 2 (TPM1-ALK RCC) showed a papillary growth pattern, with small, slender papillae accompanied by branches. The cells were arranged in a single layer, and the cytoplasm was either eosinophilic or clear. Foamy cells were aggregated in the stroma, accompanied by psammoma body-like calcifications. Case 3 (EML4-ALK RCC) was characterized by papillary and tubulocystic structures. The cytoplasm was abundant and eosinophilic. The tumor cell nuclei were large, with prominent nucleoli. There was conspicuous infiltration of lymphocytes and neutrophils in the fibromuscular stroma. The tumor cells all expressed epithelial markers, PAX8, GATA3, P504s and FH. ALK (5A4) staining showed diffuse strong expression in the cytoplasm, while TFE-3 was positive (nuclear stain) only in case 1 and case 3. The fluorescence in situ hybridization showed that ALK gene rearrangement was present in all three cases, while TFE-3 gene rearrangement/mutation was not detectable in case 1 and case 3. NGS showed the KIAA1217::ALK fusion (the fusion site in the exon 11 of KIAA1217 and exon 18 of ALK) in case 1, the TPM1::ALK fusion (the exon 8 of TPM1 and exon 20 of ALK) in case 2, and the EML4::ALK fusion (the exon 2 region of EML4 and the exon 20 region of ALK) in case 3.Conclusions:ALK-rearranged RCC has unique molecular characteristics. Its histological morphology is easily confused with that of papillary RCC and TFE3-rearranged RCC. Both immunohistochemistry and gene rearrangement tests should be used to confirm the diagnosis.