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To investigate the perforating characteristics of Zr-based bulk metallic glass fragments against thin steel target, ballistic experiments were carried out to measure ballistic the limit velocities of fragments perforating against different thicknesses of targets. The fragments were driven by a 57 mm one-stage light gas gun to impact the thin steel target. The numerical model of Zr-based bulk metallic glass fragments perforating against thin steel target was established using Autodyn2D commercial software, and the perforating process and perforating mechanism were analyzed by numerical simulation. The semi-empirical model to predict the ballistic limit velocity was fitted. An energy model for calculating the residual velocity of a fragment was derived based on the conservation of energy. The theoretical results of the semi-empirical model and the energy model are in good agreement with experiment results and simulation results. And the energy model has good applicability without fitting the parameters for different target thicknesses. [ABSTRACT FROM AUTHOR]

Colorless and transparent polymer films and sheets with good high-temperature resistance and low dielectric constant (low-Dk) and low dissipation factors (low-Df) features are highly desired in advanced optoelectronic integrated circuits (OEIC) fabrications. In the current work, a series of semi-alicyclic polyimide (PI) powders were first prepared by the onestep high-temperature polycondensation of an alicyclic dianhydride, hydrogenated 3,3',4,4'-biphenyl tetracarboxylic dianhydride (HBPDA) and aromatic diamines which were beneficial for endowing the derived PI films with low-Dk features, including 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP) for PI-1, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (BDAF) for PI-2, and 9,9-bis[4-(4-aminophenoxy)phenyl]fluorene (BAOFL) for PI-3. Then, the derived PI powders were fabricated into colorless films and light-colored sheets, respectively. The freestanding flexible and tough PI films showed excellent optical transparency with the ultraviolet (UV) cutoff wavelength (λcut) lower than 300 nm, the optical transmittance higher than 85% at the wavelength of 400 nm, yellow indices (b*) lower than 1.0, and haze values lower than 1.2%. The hot-processed PI sheets also exhibited light colors. The PI films and sheets showed good thermal stability with the glass transition temperatures (Tg) higher than 220 °C. More importantly, the derived semi-alicyclic PI sheets showed Dk and Df values as low as 2.56 and 0.008 at 1 MHz, respectively. [ABSTRACT FROM AUTHOR]

Objective: To quantify cerebral cortical and deep gray matter atrophy in patients with multiple sclerosis (MS) and explore its correlation with impairment in domains of cognitive function. Methods: Twenty patients with MS and 16 healthy controls (HC) matched for age, sex, and education level were included. Using FreeSurfer software, based on 3D-MRI technology, the differences in cortical thickness and deep gray matter volume between the two groups were comparatively analyzed. A neuropsychological scale that included six domains of cognitive function was scored on both study groups to analyze the correlation between cortical thickness and volume of deep gray matter in MS patients with impairment in cognitive function domains. Results: Impairment in domains of cognitive function: cognitive impairment was present in 60% MS patients in this study, mainly manifesting as impairment of verbal memory, verbal fluency, visuospatial memory, and information processing speed function (all P <0.05). Of these, the majority had impaired visuospatial memory function (55.0%), and the least number of patients had impaired information processing speed (15.0%). Changes in cortical thickness: compared with the HC group, the MS group showed that cortical atrophy was mainly concentrated in the frontoparietal region, including significant thinning of cortical thickness in the left inferior parietal gyrus, right superior frontal gyrus, and the right superior parietal gyrus (all P <0.05). Among them, atrophy of the left inferior parietal gyrus was significantly positively correlated with the impairment of verbal memory, verbal fluency, and information processing speed (all P <0.05). There was a significant positive correlation between the right superior frontal gyrus atrophy and verbal memory, verbal fluency, and visuospatial memory impairment (all P <0.05). Changes in deep gray matter volume: compared with the HC group, deep gray matter volume in the MS group decreased significantly in the bilateral thalamus, bilateral putamen, bilateral pallidum (all P <0.01), and right nucleus accumbens ( P <0.05). Among them, left thalamus atrophy was significantly positively correlated with visuospatial memory impairment ( r =0.45, P =0.046), and left putamen atrophy was both significantly positively correlated with visuospatial memory ( r =0.45, P =0.047) and information processing speed impairment ( r =0.50, P =0.026). Conclusions: Early structural brain changes in MS are dominated by gray matter atrophy. Deep gray matter is more prominent than cortical atrophy.

Recently, the number of severe obesity in China has now ranked first in the world. The amount of metabolic and bariatric surgery in China is increasing year by year, and has made rapid development. As more and more new hospitals, surgical teams, and physicians join the field of metabolic and bariatric surgery, suboptimal operations and managements will inevitably accompany, causing problems and hidden dangers related to bariatric surgery. To a certain extent, this is in line with the law of development, but it does not mean that we can leave it alone and let it develop. In order to ensure the sustainable, healthy and orderly development of metabolic and bariatric surgery in China in the future, the standardized construction and quality improvement have become an urgent task. This paper reviews the current status of standardized construction of metabolic and bariatric surgery at home and abroad, the necessities and paths to quality improvement of standardized construction of metabolic and bariatric surgery in China, in order to put forward some thoughts and arouse extensive discussions for the development of the subject.

Oral microbial community, as an important part of human microbial community, is closely related to oral and general health. Oral microbiological research has become the forefront of international microbiological research. Standardized and unified nomenclature for oral microorganisms in Chinese is of great significance to support the development of oral medicine research. Standardized translation of microbial names is the basis for writing canonical and authoritative professional textbooks and reference books, which helps students to accurately acquire the characteristics and classifications of oral microbes. Unified translation of oral microorganisms is also conducive to academic communication and cooperation, and plays an important role in oral health education and science popularization, which enables oral microbiology knowledge to be accurately disseminated to the public. Therefore, in order to standardize the words in scientific research, funding application, publications, academic exchanges and science popularization within the field of oral medicine, we have fully discussed and revised the Chinese names of oral microorganisms in 2017 edition and ones of newly discovered oral microbes, finally reaching a consensus to form the 2023 edition of Chinese names of oral microorganisms.

Objective: To explore the rate of Helicobacter pylori (Hp) resistance to levofloxacin and clarithromycin and the common mutation patterns of resistance genes in Ningxia, and to assess the concordance between phenotypic resistance and genotypic resistance. Methods: Cross-sectional study. Patients diagnosed with Hp infection in 14 hospitals in Ningxia region from February 2020 to May 2022 were retrospectively selected. Hp strains were isolated from gastric biopsy specimens of Hp-infected patients and subjected to phenotypic drug sensitivity testing and detection of resistance genes to analyze the rate of Hp resistance to levofloxacin and clarithromycin and the common mutation patterns of resistance genes in Ningxia region; and the concordance rate and Kappa concordance test were used to assess the concordance between phenotypic resistance and genotypic resistance. Results: A total of 1 942 Hp strains were isolated and cultured, and among the infections, 1 069 cases (55.0%) were male and 873 cases (45.0%) were female, aged (50.0±12.5) years (15-86 years). The rates of Hp resistance to levofloxacin and clarithromycin in Ningxia were 42.1% (818/1 942) and 40.1% (779/1 942), respectively, and the rate of dual resistance to both was 22.8% (443/1 942). The rate of resistance to levofloxacin and clarithromycin of Hp strains from female patients was higher than in male patients (levofloxacin: 50.4%(440/873) vs 35.4%(378/1 069); clarithromycin: 44.4%(388/873) vs 36.6%(391/1 069), both P <0.001). Among the GyrA gene mutations associated with levofloxacin resistance, the differences in mutation rate of amino acid at positions 87 and 91 were statistically significant in both drug-resistant and sensitive strains(both P <0.001), except for Asn87Thr. Hp strains were statistically significant for levofloxacin (Kappa=0.834, P <0.001) and clarithromycin (Kappa=0.829, P <0.001) had good concordance in resistance at the phenotypic and genotypic levels. Conclusion: The resistance of Hp to levofloxacin and clarithromycin in Ningxia region is severe, and there is good consistency between genotypic and phenotypic resistance.

Objective: To investigate the rate of periprosthetic joint infection (PJI) revision surgeries and clinical information of hip-/knee- PJI cases nationwide from 2015 to 2017 in China. Methods: An epidemiological investigation. A self-designed questionnaire and convenience sampling were used to survey 41 regional joint replacement centers nationwide from November 2018 to December 2019 in China. The PJI was diagnosed according to the Musculoskeletal Infection Association criteria. Data of PJI patients were obtained by searching the inpatient database of each hospital. Questionnaire entries were extracted from the clinical records by specialist. Then the differences in rate of PJI revision surgery between hip- and knee- PJI revision cases were calculated and compared. Results: Total of 36 hospitals (87.8%) nationwide reported data on 99 791 hip and knee arthroplasties performed from 2015 to 2017, with 946 revisions due to PJI (0.96%). The overall hip-PJI revision rate was 0.99% (481/48 574), and it was 0.97% (135/13 963), 0.97% (153/15 730) and 1.07% (193/17 881) in of 2015, 2016, 2017, respectively. The overall knee-PJI revision rate was 0.91% (465/51 271), and it was 0.90% (131/14 650), 0.88% (155/17 693) and 0.94% (179/18 982) in 2015, 2016, 2017, respectively. Heilongjiang (2.2%, 40/1 805), Fujian (2.2%, 45/2 017), Jiangsu (2.1%, 85/3 899), Gansu (2.1%, 29/1 377), Chongqing (1.8%, 64/3 523) reported relatively high revision rates. Conclusions: The overall PJI revision rate in 34 hospitals nationwide from 2015 to 2017 is 0.96%. The hip-PJI revision rate is slightly higher than that in the knee-PJI. There are differences in revision rates among hospitals in different regions.

Objective: A permanent stoma can seriously affect patients' quality of life. Clinicians need to consider the risk of a permanent stoma when making clinical decisions. This study analyzed preoperative predictors of a permanent stoma after laparoscopic intersphincteric resection for low rectal cancer (LISR), and a prediction model was constructed validated. Methods: This was a retrospective study that analyzed clinical data of 331 ultralow rectal cancer patients who were diagnosed with primary rectal adenocarcinoma by endoscopy and pathology, including 218 males and 113 female, (58.8±11.2) years and (23.7±3.1) kg/m 2 . The patients underwent LISR with a preventive stoma from January 2012 to December 2020. Patients with multiple primary colorectal cancers, who underwent emergency surgery for intestinal obstruction or bleeding or perforation, and did not complete 18 months follow up were exclucled. R software was used to randomly select 234 patients as the modeling group with a ratio of approximately 7:3, and the remaining 97 patients comprised the validation group. The stoma site was determined by the surgeon before the operation, and the ileum 30 cm from the ileocecal valve was selected. The rates of a permanent stoma for the entire group and the preoperative clinical factors that may affect the permanency of a stoma in the modeling group were determined. A permanent stoma was defined as failure to close the stoma at 18 months after surgery. Multivariate logistic regression analysis was used to analyze the preoperative independent risk factors for a permanent stoma after LISR. R software was used to create the nomogram model, and the predictive ability of the nomogram model was evaluated by receiver operating characteristic (ROC) curve analysis. Results: Among the 331 patients who underwent LISR, 37 (26 cases in the modeling group and 11 cases in the validation group, 11.2%) developed a permanent stoma for the following reasons: anastomotic stenosis due to leakage (16 cases, 43.2%), distant metastasis (16 cases, 43.2%), intolerant to stoma closure surgery (3 cases, 8.1%), stenosis due to postoperative radiation (1 case, 2.7%), and poor recovery of anorectal function (1 case, 2.7%). Univariate analysis showed that preoperative neoadjuvant chemoradiotherapy, poorly differentiated tumor, cT3 stage, and distant metastasis were associated with a permanent stoma. Multivariate logistic regression analysis showed that neoadjuvant chemoradiotherapy [OR=3.078, 95% confidence interval (CI): 1.326-7.147; P =0.009], cT3 stage (OR=2.257, 95%CI: 1.001-5.091; P =0.049), and stage IV cancer (OR=16.180, 95%CI: 2.753-95.102; P =0.002) were independent risk factors for permanent stoma after LISR. Based on the selected risk factors, a nomogram model for predicting permanent stoma was constructed. The area under the ROC curve of the modeling group was 0.793, the optimal cut-off value was 0.890, the sensitivity was 0.577, and the specificity was 0.885. The area under the ROC curve of the validation group was 0.953. The corrected curves of the modeling group and the validation group showed a good degree of fit. Conclusion: Neoadjuvant chemoradiotherapy, cT3 stage, and distant metastasis are independent predictors of a permanent stoma after LISR, and the nomogram model is helpful to predict the probability of a permanent stoma. Patients with high-risk factors should be adequately informed of the risk of a permanent stoma before colorectal surgery.

With the improvement of the national economy and living standards, the prevalence of obesity and related metabolic diseases is increasing yearly. The treatment effect of traditional diet control, physical exercise, and drug therapy are not ideal. Metabolic and bariatric surgery is not only aimed at weight loss, but also improves or resolves a variety of metabolic comorbidities, such as type 2 diabetes, hypertension, sleep apnea syndrome, and hyperlipidemia, enhancing the quality of life of patients. Surgical methods are also updated and iterated with the continuous development of metabolic surgery for weight loss. At present, more than 50% of the mainstream procedures are laparoscopic sleeve gastrectomy (LSG). The application of LSG should focus on precise surgical operations and indications to avoid or reduce adverse reactions and complications, so as to maximize the effect of bariatric surgery. At the same time, standardized postoperative management, multidisciplinary team (MDT) and in-hospital database construction, dietary nutrition and exercise guidance after discharge, and regular follow-up review are still important guarantees for the weight loss effect.

Objective: To evaluate the safety and efficacy of distal rectal transection by using transanterior obturator nerve gateway (TANG) in laparoscopic radical resection for lower rectal cancers. Methods: A descriptive case series study was performed. Inclusion criteria: (1) patients with primary rectal adenocarcinoma, with the distance of 3-5 cm from tumor to anal verge, with normal anal function before surgery and a desire to preserve anus; (2) laparoscopic radical resection of rectal cancer was performed and the distal rectum was transected using TANG approach. Exclusion criteria: (1) patients with distant metastasis or receiving palliative surgery; (2) the distal rectum was transected using non-TANG approach; (3) patients receiving combined multiple organs resection; (4) patients complicated with other tumors requiring additional treatment during the study. Clinicopathological data of 50 patients with low rectal cancer undergoing laparoscopic resection using TANG approach between January 2019 and December 2020 in Peking University First Hospital were retrospectively collected. Perioperative conditions, length of specific pelvic lines, additional angle and postoperative short-term outcomes were observed and described. Additional angle was defined as the angle between the simulated stapling line with the traditional approach and the real stapling line with the TANG approach. Data following normal distribution were presented as Mean±SD, or M [quartile range ( Q (R))] otherwise. Results: All the patients successfully completed laparoscopic surgery without transferring to open or transanal surgery. The median operative time was 193 (80) min and blood loss was 50 (58) ml. All tumors received R0 resection with the distance from the tumor to distal resection margin of 1.7 (0.4) cm and the anastomotic height of 2.0 (0.1) cm. Rectal transection was completed by one cartridge in 52.0% of the cases (26/50) and two cartridges in 48.0% (24/50). Length of the stapling line was 6.6 (1.5) cm. The time to construct the gateway was 8.0 (6.0) min. The vessel damage occurred in 4.0% of the cases (2/50) and none of the cases encountered obturator nerve damage. Inlets of the pelvis in TANG and traditional approach were (9.9±1.3) cm vs. (7.2±1.1) cm ( t =24.781, P <0.001). Additional angle of TANG was (15±2) °. The transecting positions on the midline and right edge of the rectum specimen by TANG were 0.6 (0.2) cm and 1.0 (0.2) cm lower than those by the traditional approach. One case (2.0%) died of pulmonary infection on the 17th day after surgery, 2 cases (4.0%) received re-operation and 14 cases (28.0%) had postoperative complications, including anastomotic leakage (7/50, 14.0%), urinary retention (6/50, 12.0%), pelvic infection (2/50, 4.0%) and ileus (2/50, 4.0%). The median postoperative hospital stay was 12 (6) days. Conclusions: Laparoscopic distal rectal transection by using TANG approach is safe and effective in the treatment of low rectal cancer. As an alternative rectal transecting method, TANG has advantages especially for the obese and those with a contracted pelvis and ultralow rectal cancers.

Objective: To describe and analyze the clinical manifestations of patients with orofacial pain of temporomandibular disorders (TMD). Methods: A retrospective study on orofacial pain was conducted for 3 425 patients diagnosed as TMD based on clinical symptoms and signs in the Department of Temporomandibular Disorders and Orofacial Pain, School of Stomatology, The Fourth Military Medical University. The patients included 1 158 males and 2 267 females with a median age of 32 years. The gender, age, course of disorders, pattern and site of pain, CT imaging diagnosis of temporomandibular joint (TMJ) were analyzed. The distribution of gender, age and disorder course interval were described. The differences in frequency of the pattern and site of pain, imaging diagnosis in different gender, age and disease course interval were compared. Chi-square test and non-parametric rank sum test were performed using software SPSS 23.0. Results: Of the 3 425 patients, 29.1% (997/3 245) had signs of joint popping, and 40.1% (1 373/3 425) had restricted opening. The pain frequency was higher in males who had disorder course less than 1 month ( P <0.01) and also in males who had open-and-close and/or lateral excursion and/or protrusion pain without tenderness or other pain without tenderness ( P <0.05). However, the pain frequency was higher in females who had tenderness ( P <0.01). The pain frequencies in those over 56 years old with tenderness combined with open-and-close and/or lateral excursion and/or protrusion pain were higher than in patients of other ages ( P <0.01). In patients with unilateral TMJ pain, the frequency in males was higher than females( P <0.01), while the frequency in females was higher in patients with unilateral TMJ pain combined with unilateral or bilateral myalgia and the frequency was higher in patients under 15 years old having bilateral TMJ pain and/or unilateral or bilateral myalgia ( P <0.05). In patients with unilateral TMJ pain, the frequency in those with disorder course≤1 month was higher than in those with other disease duration intervals ( P <0.01), while in patients with bilateral myalgia or TMJ pain plus unilateral or bilateral myalgia, the frequency in those with disorder course>3 years was higher than in those with other disease duration intervals( P <0.01). In patients with unilateral TMJ pain, the frequency was higher in those having open-and-close and/or lateral excursion and/or protrusion pain ( P <0.01). In patients with unilateral myalgia and bilateral myalgia, the frequency was higher in those having tenderness ( P <0.01). The frequency of TMJ space changes in male patients was higher than females and the frequency of hyperosteogeny and resorption in females were higher than males ( P <0.05). The frequency of TMJ space changes and developmental problems were higher in patients aged 16 to 35 years, while the frequencies of hyperosteogeny, bone resorption and cystis in those over 56 years were higher than other ages ( P <0.01). The frequency of TMJ space changes in patients with disorder course≤1 month was higher than in those with other disease duration intervals ( P <0.01), while the frequency of hyperosteogeny was higher in patients with disorder course>3 years ( P <0.01). Conclusions: The male to female ratio in the present patients with orofacial pain of TMD was about 1 to 2. Most of the patients visited hospital within half a year after the disorders occurred. The pattern and site of the orofacial pain, signs on TMJ CT images showed some distribution regularities in views of gender, age and disorder course.

The organoid is a kind of distinctive micro-organ formed by stem cells with the ability of self-renewal, which can be cultured in three-dimensional scaffold in vitro . With the development of cell culture system, organoids have been gradually applied in researches such as in vitro organ model establishment, drug testing and even the repairing or replacing damage organs. It shows significantly promising prospects. This review article aims to summarize the latest research progress and provide the theoretical foundation and prospects for the development of organoids in stomatology.