BACKGROUND: Owing to shortage of surgical and N95 filtering facepiece respirators (FFRs) during the COVID-2019 pandemic, various masks were developed to prevent infection. This study aimed to examine the inward leakage rate (ILR) of sealed face masks and modified surgical masks using a quantitative fit test and compared it with the ILR of unmodified N95 FFRs. METHODS: We conducted paired comparisons of ILRs of bent nose-fit wire masks, double masks, and N95 FFRs from October to December 2021. To measure the protective effectiveness of masks, participants wore masks, and the number of particles outside and inside the mask were measured. The ILR was based on the percentage of particles entering the mask using a fit tester. RESULTS: We enrolled 54 participants (20 men and 34 women) in this study. The median ILR for surgical masks without and with a W-shaped bend in the nose-fit wire were 96.44% and 50.82%, respectively. The nose-fit wire adjustment reduced the ILR of surgical masks by a mean of 28.57%, which was significantly lower than the ILR without adjustment (P < 0.001). For double masks, with surgical or polyurethane masks on top of the W-shaped mask, the ILR did not differ significantly from that of N95. Although the filtration performance of double surgical masks matched that of N95 masks, their ILR was notably higher, indicating that double masks do not provide equivalent protection. CONCLUSIONS Wearing N95 masks alone is effective in many cases. However, surgical mask modifications do not guarantee consistent effectiveness. Properly selected, sealed masks with a good fit overcome leakage, emphasizing their crucial role. Without evidence, mask-wearing may lead to unexpected infections. Education based on quantitative data is crucial for preventing adverse outcomes.
Male ; Humans ; Female ; N95 Respirators ; COVID-19/epidemiology* ; Masks ; Pandemics/prevention & control* ; Respiratory Protective Devices ; Materials Testing ; Equipment Design ; Occupational Exposure/prevention & control*

The portable light-weight magnetic resonance imaging system can be deployed in special occasions such as Intensive Care Unit (ICU) and ambulances, making it possible to implement bedside monitoring imaging systems, mobile stroke units and magnetic resonance platforms in remote areas. Compared with medium and high field imaging systems, ultra-low-field magnetic resonance imaging equipment utilizes light-weight permanent magnets, which are compact and easy to move. However, the image quality is highly susceptible to external electromagnetic interference without a shielded room and there are still many key technical problems in hardware design to be solved. In this paper, the system hardware design and environmental electromagnetic interference elimination algorithm were studied. Consequently, some research results were obtained and a prototype of portable shielding-free 50 mT magnetic resonance imaging system was built. The light-weight magnet and its uniformity, coil system and noise elimination algorithm and human brain imaging were verified. Finally, high-quality images of the healthy human brain were obtained. The results of this study would provide reference for the development and application of ultra-low-field magnetic resonance imaging technology.
Humans ; Magnetic Resonance Imaging/methods* ; Magnetic Resonance Spectroscopy/methods* ; Head ; Equipment Design ; Magnets

The ossicular replacement prosthesis should have good biocompatibility, stability, easy to install, and excellent sound transmission capacity. In this study, the characteristics of ideal materials for the ossicular replacement prosthesis were analyzed by searching the types of materials used in clinical practice and comparing the advantages and disadvantages of various materials and structures. At the same time, in combination with the current evaluation requirements and evaluation experience, the focus of the performance research project of ossicular replacement prosthesis in the process of registration is discussed to clarify the performance evaluation requirements of these products, so as to provide reference for the future work of manufacturers and regulators. The performance evaluation of ossicular replacement prosthesis focuses on its mechanical properties, fixation stability, sound transmission characteristics, biological characteristics, and magnetic resonance compatibility.
Ossicular Prosthesis ; Ossicular Replacement ; Sound ; Prosthesis Design ; Treatment Outcome

BACKGROUND: There are few data comparing clinical outcomes of complex percutaneous coronary intervention (CPCI) when using biodegradable polymer drug-eluting stents (BP-DES) or second-generation durable polymer drug-eluting stents (DP-DES). The purpose of this study was to investigate the safety and efficacy of BP-DES and compare that with DP-DES in patients with and without CPCI during a 5-year follow-up. METHODS: Patients who exclusively underwent BP-DES or DP-DES implantation in 2013 at Fuwai Hospital were consecutively enrolled and stratified into two categories based on CPCI presence or absence. CPCI included at least one of the following features: unprotected left main lesion, ≥2 lesions treated, ≥2 stents implanted, total stent length >40 mm, moderate-to-severe calcified lesion, chronic total occlusion, or bifurcated target lesion. The primary endpoint was major adverse cardiac events (MACE) including all-cause death, recurrent myocardial infarction, and total coronary revascularization (target lesion revascularization, target vessel revascularization [TVR], and non-TVR) during the 5-year follow-up. The secondary endpoint was total coronary revascularization. RESULTS: Among the 7712 patients included, 4882 (63.3%) underwent CPCI. Compared with non-CPCI patients, CPCI patients had higher 2- and 5-year incidences of MACE and total coronary revascularization. Following multivariable adjustment including stent type, CPCI was an independent predictor of MACE (adjusted hazard ratio [aHR]: 1.151; 95% confidence interval [CI]: 1.017-1.303, P  = 0.026) and total coronary revascularization (aHR: 1.199; 95% CI: 1.037-1.388, P  = 0.014) at 5 years. The results were consistent at the 2-year endpoints. In patients with CPCI, BP-DES use was associated with significantly higher MACE rates at 5 years (aHR: 1.256; 95% CI: 1.078-1.462, P  = 0.003) and total coronary revascularization (aHR: 1.257; 95% CI: 1.052-1.502, P  = 0.012) compared with that of DP-DES, but there was a similar risk at 2 years. However, BP-DES had comparable safety and efficacy profiles including MACE and total coronary revascularization compared with DP-DES in patients with non-CPCI at 2 and 5 years. CONCLUSIONS Patients underwent CPCI remained at a higher risk of mid- to long-term adverse events regardless of the stent type. The effect of BP-DES compared with DP-DES on outcomes was similar in CPCI and non-CPCI patients at 2 years but had inconsistent effects at the 5-year clinical endpoints.
Humans ; Drug-Eluting Stents/adverse effects* ; Myocardial Infarction/complications* ; Polymers/therapeutic use* ; Treatment Outcome ; Coronary Artery Disease/complications* ; Percutaneous Coronary Intervention/adverse effects* ; Absorbable Implants ; Prosthesis Design

OBJECTIVE: To compare the long-term follow-up effect and complications of ceramic on ceramic (CoC) interface and ceramic on polyethyleneon ceramic (CoP) interface in primary total hip arthroplasty, and provide clinical evidence. METHODS: Search PubMed, EMBase, the CoChrane Library databases, Web of science, Wanfang database, and CNKI from January 2000 to September 2021, screening and inclusion of randomized controlled trials (RCTs) comparing the long-term efficacy and complications of CoC interface and CoP interface in total hip arthroplasty. Literature screening, quality evaluation and data extraction were carried out according to the inclusion and exclusion criteria, using Review Manager 5.3 statistical software. The software was used to perform statistical analysis on joint function, revision, prosthesis fracture, abnormal joint noise, and prosthesis wear rate after CoC or CoP. RESULTS: Seven RCTs studies were included, including 390 cases of hips with CoC artificial joints and 384 cases of hips with CoP artificial joints. The long-term joint function improvement of CoC and CoP artificial joints was similar and there was no significant differences, with an average difference was MD=0.63, 95%CI=(-1.81, 3.07), P=0.61. About the postoperative complications, CoC artificial joints have higher incidence rate of abnormal joint noise, with odds ratio (OR)=11.05, 95%CI=(2.04, 59.84), P=0.005. CoP artificial joints wear faster, with an average MD=-87.11, 95%CI=(-114.40, -59.82), P<0.000 1. There was no significant difference between the two groups in the replacement-related complications such as joint dislocation, prosthesis loosening, osteolysis, and the rate of prosthesis revision caused by various reasons. CONCLUSION The clinical function results and complications of CoC artificial joints are comparable to those of CoP artificial joints. Although CoP artificial joint prosthesis has a faster wear rate, it does not affect joint function and increase complications, and there is no abnormal joint noise. CoC is expensive and the long-term efficacy is equivalent to CoP. Clinicians should consider cost performance when choosing CoC.
Humans ; Arthroplasty, Replacement, Hip/methods* ; Hip Prosthesis ; Follow-Up Studies ; Prosthesis Design ; Polyethylene ; Prosthesis Failure ; Reoperation ; Ceramics ; Treatment Outcome

OBJECTIVE: To predict the learning curve of tooth preparation for all ceramic crowns of maxillary central incisors on phantom head simulators for graduate students participating in standardized dental resident training based on the modified Wright learning curve model, then to analyze and applicate the learning curve. METHODS: Twelve graduate students participating in standardized dental resident training were selected to prepare the resin maxillary central incisors on phantom head simulators for all ceramic crowns 4 times. The results of preparation were evaluated by 3 prosthetic experts with at least 10 years' experience focusing on the reduction, contour, taper, shoulder, finish line, margin placement, adjacent tooth injury, and preparation time for tooth preparation. The learning rate of tooth preparation was calculated by scores of tooth preparation of 4 times. The learning curve of tooth preparation was predicted based on the modified Wright learning curve model. According to the criteria of standardized training skill examinations for dental residents in Beijing, 80 was taken as the qualified standard score. The minimum training times for tooth preparation to satisfy the qualified standard score (80) was calculated, to analyze the characteristics of learning curve and evaluate the effectiveness of tooth preparation. RESULTS: The scores of 4 tooth preparation were 64.03±7.80, 71.40±6.13, 74.33±5.96, and 75.98±4.52, respectively. The learning rate was (106±4)%, which showed the learning curve an upward trend. There were no significant differences between the qualified standard score and the predicted scores of tooth preparation from the 5^th preparation to the 13^th preparation (P > 0.05). The predicted score of the 14^th preparation was higher than the qualified standard score (P < 0.05). CONCLUSION The trend of the learning curve of tooth preparation for all ceramic crowns of maxillary central incisors on phantom head simulators for graduate students participating in standardized dental resident training is upward, which predicts the minimum training times higher than the qualified standard score is 14 times.
Humans ; Tooth Preparation, Prosthodontic/methods* ; Incisor ; Learning Curve ; Crowns ; Tooth Preparation ; Ceramics ; Dental Porcelain ; Dental Prosthesis Design

Three different preclinical evaluation methods of MTF through-frequency response, MTF through-focus-response and expected visual acuity were used to compare and analyze the imaging differences of IOLs with four different optical designs. The research work could be used in the simultaneous vision IOLs in the optical design stage and verify the optical quality of the IOLs, the results can predict the visual representation of the patients better. The evaluation results can provide reference for IOL manufacturers and users in product design, development, validation and application selection.
Humans ; Prosthesis Design ; Lenses, Intraocular ; Vision, Ocular ; Visual Acuity

Objective: To explore the indications and management of common postoperative complications of phase II tracheoesophageal puncture (TEP) for Provox Vega voice prosthesis after total laryngectomy. Methods: The clinical data of 20 patients undergoing phase II TEP for Provox Vega voice prosthesis in our hospital between May 2021 and January 2022 were analyzed. Among them, there were 19 males and 1 female, aged from 37 to 76 years, with an average age of (60.0±8.4)years. The surgical indications and the prevention and treatment of common postoperative complications were summarized. Descriptive analysis was used in this research. Results: The basic surgical indications were as following: after total laryngectomy, there was no stenosis of the stoma and esophagus entrance, no scar constitution, no mouth opening restriction, no stiffness and backward restraint of the neck after radiotherapy, and more than half a year apart surgery or radiotherapy. Among the 20 patients, 18 underwent implantation successfuly, 1 failed in the operation, and for 1 patient, the prosthesis was removed due to bleeding 1 week after implantation. The common postoperative complications included TEP fistula infection (2 cases), the TEP fistula bleeding(1 case), deep neck (prevertebral) abscess (1 case), granulation at the inner side of the TEP fistula (1 case), invagination of the prosthesis (2 cases) and leakage around the prosthesis (2 cases). All patients were cured with different interventions. Conclusions: The Provox Vega voice prosthesis is generally safe for phase Ⅱ implantatione, but implantation indications need to be established. Common postoperative complications can be solved through preventive and remedial interventions.
Male ; Humans ; Female ; Larynx, Artificial/adverse effects* ; Laryngectomy/adverse effects* ; Prosthesis Implantation/adverse effects* ; Esophagus/surgery* ; Postoperative Complications/etiology* ; Prosthesis Design

OBJECTIVE: Using the mono-energy reconstruction images and X-ray films to investigate whether the ABG Ⅱ short-stem could improve the filling ratio, stability, and alignment in the Dorr type C femur, compared with the Corail long-stem. METHODS: Among patients who were with Dorr type C femurs and treated with total hip arthroplasty between January 2006 and March 2012, 20 patients with a Corail long-stem (Corail group) and 20 patients with an ABG Ⅱ short-stem (ABG Ⅱ group) were randomly selected. The differences in gender, age, body mass index, and preoperative diagnoses between the two groups were not significant ( P>0.05). The ABG Ⅱ group was with a mean follow-up of 142 months (range, 102-156 months), and the Corail group was with a mean follow-up of 107 months (range, 91-127 months). There was no significant difference in the Harris score and subjective satisfaction score between the two groups at last follow-up ( P>0.05). At last follow-up, dual-energy CT scans with mono-energy image reconstruction were used to calculate the prosthetic filling ratio and to measure the alignment of the prosthesis in the coronal and sagittal positions. Stability assessment was performed based on X-ray films, and the subsidence distance was measured using EBRA-FCA software. RESULTS: X-ray film observation showed that the prostheses in the two groups were stable and no signs of loosening was found. The incidence of pedestal sign was significantly lower in the ABGⅡ group than in the Corail group ( P<0.05), and the incidence of heterotopic ossification was significantly higher in the ABGⅡ group than in the Corail group ( P<0.05). The subsidence distance of femoral stem in ABG Ⅱ group was significantly greater than that in Corail group ( P<0.05), and the subsidence speed of femoral stem in ABG Ⅱ group was also greater than that in Corail group, but the difference was not significant ( P>0.05). The overall prosthesis filling ratio was significantly higher in the ABG Ⅱ group than in the Corail group ( P<0.05), while the coronal filling ratio at the lesser trochanter, 2 cm below the lesser trochanter, and 7 cm below the lesser trochanter were not significant ( P>0.05). The results of prosthesis alignment showed that there was no significant difference in the sagittal alignment error value and the incidence of coronal and sagittal alignment error >3° between the two groups ( P>0.05), while the coronal alignment error value in the ABG Ⅱ group was significantly greater than that in the Corail group ( P<0.05). CONCLUSION Although the ABG Ⅱ short-stem avoids the distal-proximal mismatch of the Corail long-stem in the Dorr type C femur and thus achieves a higher filling ratio, it does not appear to achieve better alignment or stability.
Humans ; Arthroplasty, Replacement, Hip/methods* ; Femur/surgery* ; Hip Prosthesis ; Lower Extremity/surgery* ; Prosthesis Design ; Retrospective Studies

Oxygen therapy is an effective clinical method for the treatment of respiratory disorders, oxygen concentrator as a necessary medical auxiliary equipment in hospitals, its research and development has been a hot spot. The study reviewed the development history of the ventilator, introduced the two preparation technique of the oxygen generator pressure swing absorption (PSA) and vacuum pressure swing adsorption (VPSA), and analyzed the core technology development of the oxygen generator. In addition, the study compared some major brands of oxygen concentrators on the market and prospected the development trend of oxygen concentrators.
Oxygen ; Oxygen Inhalation Therapy ; Hospitals ; Ventilators, Mechanical ; Equipment Design