Comparison of the inward leakage rate between N95 filtering facepiece respirators and modified surgical masks during the COVID-19 pandemic

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.

Medición del dolor durante el trabajo de parto: evaluación de la usabilidad de un nuevo dispositivo / Pain measurement during labor: usability evaluation of a new device

Objetivo: Evaluar la usabilidad de un dispositivo para medir el dolor durante el trabajo de parto a través de siete ítems: tamaño, textura, facilidad de uso, peso, resistencia, comodidad y seguridad. Método: Estudio descriptivo. Se solicitó a 60 pacientes usar el sensor manual durante el transcurso de seis contracciones uterinas (aproximadamente 10-20 minutos) y al día siguiente se aplicó una encuesta en la que las pacientes evaluaron la usabilidad del dispositivo en cuanto a textura, peso, resistencia, comodidad, facilidad de uso, tamaño del sensor, seguridad de uso, peso del sensor, resistencia y comodidad, mediante una escala de Likert de 1 a 7. La seguridad fue evaluada con una escala de 1 a 5. Resultados: Se realizaron gráficos de caja. Con respecto a la seguridad, un 86% de las usuarias marcaron 5 puntos en la escala, percibiendo el dispositivo como seguro. Conclusiones: El dispositivo fue percibido como seguro, liviano, fácil de usar y cómodo.

Objective: To evaluate the usability of a device to measure pain during labor through seven items: size, texture, ease of use, weight, resistance, comfort, and safety. Method: Longitudinal observational study. 60 patients were asked to use the manual sensor during the course of six uterine contractions (approximately 10-20 minutes) and the following day a survey was applied where the patients evaluated the usability of the device in terms of texture, weight, resistance, comfort, easiness of use, sensor size, safety of use, sensor weight, resistance and comfort through a Likert scale from 1 to 7. Safety was evaluated with a scale from 1 to 5. Results: They were schematized with a box plot. Regarding safety, 86% of the users scored 5 points on the scale, perceiving the device as safe. Conclusions: It can be seen that the device was perceived as safe, light, easy to use and comfortable.

Research on a portable shielding-free ultra-low field magnetic resonance imaging system / 生物医学工程学杂志

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.

Research and Development Trend of Medical Oxygen Production Equipment / 中国医疗器械杂志

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.

Adaptation and acceptability testing of the Expector® vibration vest in horses / Adaptação e teste de aceitabilidade do colete de vibração Expector® em equinos

The project is based on a test of a thoracic vibration vest prototype, adapted to equines by the Expector® vest's company, on healthy animals. Ten (10) equines were used in the project, male or female, adults, healthy, belonging to FMVZ-USP or private owners. Each animal went through two phases: A and B. Phase A consisted of the placement of the vest without turning on the vibrators, evaluating the animal's acceptability, facility, adaptation to the animal's body, and discomfort due to the vest's use. Phase B included the placement of the vest and turning on the vibrators, evaluating the animal's acceptability, reaction to the vibrators, and, if present, to which velocity/type of vibration, and the presence of adverse effects. Both phases were done three times on separate days. The behavioral parameters: "placement facility" and "adaptation to the animal's body" were observed. In phase B, the response to the vibration was classified from 0 to 5. The answer was evaluated on low and high intensities for the four vibration types. The heart rate (HR) and respiratory rate (RR) were also evaluated at the beginning and end of each repetition. The animals' HR was kept on normal, except for one animal on one day of the test. Concerning the RR, most animals presented moments of tachypnea. On the experiment's first day, 100% of grade Great to "facility of placement" and "adaptation to the animal's body" was obtained, but on days 2 and 3 this value dropped to 90% due to alterations in one animal's responses. Regarding vibration's responses, 77.3% were evaluated as no discomfort (grade 0), 17.1% little discomfort (grade 1), 3.3% medium discomfort (grade 2), 0.4% great discomfort (grade 3), 0.21% extreme discomfort (grade 4), and 1.6% non-acceptance of the vest (grade 5). Some possible changes on the prototype were also verified to be suggested to the manufacturer, such as the change of the buckle and the use of wireless control. Vest use appears promising for equine respiratory physiotherapy, considering the acceptability was good, and its efficiency on the expectoration of diseased animals must be tested.

O projeto consistiu no teste de um protótipo de colete de vibração torácica, adaptado aos equinos pela empresa do colete Expector®, em animais saudáveis. Foram utilizados 10 equinos, machos ou fêmeas, adultos, saudáveis, pertencentes à FMVZ-USP e a proprietários particulares. Cada animal passou por duas fases: A e B. A Fase A consistiu na colocação do colete sem ligar os vibradores, avaliando-se a aceitabilidade do animal; facilidade; adaptação ao corpo do animal e incômodo do mesmo à sua presença. Já a Fase B contava com a colocação do colete e funcionamento dos vibradores, avaliando-se a aceitabilidade do animal; reação aos vibradores e, se presente, a qual velocidade/tipo de vibração; presença de reações ou efeitos adversos. As duas fases foram realizadas em triplicata em dias separados. Foram observados os parâmetros comportamentais "facilidade de colocação" e "adaptação ao corpo do animal". Na fase B, a resposta à vibração foi classificada de 0 a 5. A resposta foi avaliada nas intensidades baixa e alta para os quatro diferentes tipos de vibração. Foram avaliadas também as frequências cardíaca (FC) e respiratória (FR) no início e final de cada repetição. A FC dos animais se manteve dentro do intervalo de normalidade, com exceção de um animal em um dia de avaliação. Em relação à FR, a maioria apresentou momentos de taquipneia. No primeiro dia de experimento obteve-se 100% de avaliação Ótima para "facilidade de colocação" e "adaptação ao corpo do animal", mas nos dias 2 e 3 esse valor caiu para 90% devido à alteração na resposta de um animal. Em relação à resposta à vibração, 77,3% das respostas foram avaliadas como nenhum incômodo (nota 0), 17,1% pouco incômodo (nota 1), 3,3% médio incômodo (nota 2), 0,4% muito incômodo (nota 3), 0,21% incômodo extremo (nota 4) e 1,6% não aceitação do colete (nota 5). Foram também verificadas algumas possíveis mudanças no protótipo a serem sugeridas ao fabricante, como mudança do tipo de fivela e uso de controle sem fio. A utilização do colete parece ser muito promissora para a fisioterapia respiratória em equinos, visto que a aceitabilidade foi muito boa, devendo-se agora realizar a avaliação de sua eficácia na expectoração de animais enfermos.(AU)

Evolution and development: engine-driven endodontic rotary nickel-titanium instruments / 国际口腔科学杂志·英文版

Various engine-driven NiTi endodontic files have been indispensable and efficient tools in cleaning and shaping of root canals for practitioners. In this review, we introduce the relative terms and conceptions of NiTi file, including crystal phase composition, the design of the cutting part, types of separation. This review also analysis the main improvement and evolution of different generations of engine-driven nickel-titanium instruments in the past 20 years in the geometric design, manufacturing surface treatment such as electropolishing, thermal treatment, metallurgy. And the variety of motion modes of NiTi files to improve resistance to torsional failure were also discussed. Continuous advancements by the designers, provide better balance between shaping efficiency and resistance to of NiTi systems. In clinical practice an appropriate system should be selected based on the anatomy of the root canal, instrument characteristics, and operators' experience.

An Integrated Digital Magnetic Resonance Imaging Spectrometer / 中国医疗器械杂志

An integrated digital magnetic resonance imaging spectrometer was proposed in this study. By using the FPGA chip Artix7 200T, timing control, data processing, digital frequency conversion and phase control were implemented into a single-chip, thus effectively improved timing accuracy and phase accuracy, while avoided the structural design complexity caused by multi-board connection and improved system integration and imaging quality.

Realization and Clinical Study of Robotic Technology in Cardiovascular Interventional Surgery / 中国医疗器械杂志

The high incidence of cardiovascular diseases is a serious threat to human health, and endovascular surgery has become the standard treatment for most interventional cardiovascular diseases. The robotassisted endovascular surgery system further enhances surgeons' ability to perform minimally invasive endovascular procedures in interventional cardiology. This study presents a new robotic technique for coronary intervention from the perspective of clinical application. Aiming at clinical application scenarios, this scheme proposed an intuitive guide wire catheter mechanism design, which accurately and perfectly simulates the doctor's hand movements, realizes the positive and negative direction translation of the guide wire catheter, accurate torque control of the guide wire rotation and locking. The results of animal test showed that the R-OneTM has a high degree of dexterity, accuracy and stability,and meets the clinical needs.

Discussion on Testing and Standard of Blood Pressure Sensor at the Tip of Catheter / 中国医疗器械杂志

With the implementation of the new policy for coronary stent centralized volume purchasing in China, the blood pressure sensor at the tip of the catheter, as one of the essential medical instruments for the diagnosis and treatment of coronary artery disease, will meet the new development opportunity of the industry, a number of medical device companies will actively participate in the development and registration of the catheter tip blood pressure sensor. As an invasive blood pressure sensor, the catheter tip blood pressure sensor should meet the current effective industry standard YY 0781-2010, however, there are many problems when using YY 0781-2010 as a blood pressure sensor because of the difference of product structure and working mode. In this paper, the problems about "Operation Manual", "electrical performance" and "safety requirement" in the course of carrying out YY 0781- 2010 with the blood pressure sensor on the tip of catheter are discussed and analyzed in detail, hope to provide some inspiration for more research and development enterprises of blood pressure sensors on the tip of catheters and inspectors of medical device testing institutions, also hope to be able to contribute to the high-quality development of blood pressure sensor industry at the tip of the Catheter.

Design and Experimental Research of Portable Extracorporeal Circulation Pipeline Performance Testing System / 中国医疗器械杂志

Aiming at the current situation of performance testing of hemodialysis extracorporeal circulation tubing, which has slow efficiency, inaccurate measurement, and inconvenient testing, a portable detection system for testing the performance of hemodialysis extracorporeal circulation tubing is designed. The system mainly includes a hardware system and a software system. The hardware system uses STM32F407 single-chip microcomputer as the core to design the driving control of the roller pump; the software system uses the C++ real-time operating system, and the flow detection data is transmitted to the upper computer through RS485 communication and displayed. Experimental showed that the system detects the accuracy and the stability of the flow rate. It has the characteristics of stability and high precision. The relative error of the experimental measurement is within the range of ±10%. The weight of the whole machine is 2 kg, which improves the efficiency by 50% compared with the traditional detection method.

Portable Monitoring Device for Motor Rehabilitation Equipment with Rotor Shaft / 中国医疗器械杂志

A novel and portable device is proposed to monitor motor rehabilitation equipment, which can be mounted on most equipment with rotor shaft. The software of the device, whose main functions include equipment configuration, monitoring and statistical computation, is developed based on available sensor. The data collected by the device serve both department managers to learn the efficiency of the equipment, and physicians and therapists to understand the physical conditions of the patients who perform training exercises with the monitored rehabilitation equipment. About 2000 hours' monitoring has been carried out, and the experimental result indicates that the monitoring device is applicable to many types of motor rehabilitation equipment and achieves good monitoring accuracy. The data aggregated by the device can be used to evaluate the motor functions of the patients and make rehabilitation training plan. Besides, it is agreed by physicians and therapists that the device is easy-to-use, robust and has good real-time performance. The monitoring device thus holds the promise of boosting the development of digitalized rehabilitation medicine.

Evaluation on Surgical Robotic Pose Repeatability Based on Laser Tracking Measurement / 中国医疗器械杂志

To provide accurate information for registration and safety evaluation of surgical robot, the pose repeatability measurement method was proposed. According to the terminal instrument of the master-slave surgical robot (such as high-frequency electric knife, ultrasonic knife), a suitable target ball fixture was designed. The node data at 10%, 50% and 100% rated speed were measured respectively. Through data analysis, the pose repeatability property of the tested samples at different speeds was obtained. It has high applicability and repeatability, and can meet the requirements of data traceability and registration testing.

Research and Implementation of 433 MHz-based Wireless Implantable Pacing System / 中国医疗器械杂志

In order to solve the problem of communication interference and communication distance caused by the rapid pacing system when establishing the rapid atrial fibrillation model, a low-power implantable pacing system based on 433 MHz communication frequency to form a star network is designed. The system includes an implantable pacemaker, a programmer head, and programmer software. The pacemaker is composed of a wireless communication module, a pacing module, an ECG monitoring module, and a power management module. The programmer head acts as an intermediate node in the star network and is controlled by PC programmer software to program each pacemaker. This article introduces the hardware design and software flow of each part of the system, and describes the results of in vivo simulation and in vivo animal models of the system. The results show that the designed system and application method are effective and feasible for the rapid atrial pacing atrial fibrillation model. 433 MHz wireless communication, implantable, pacemaker system, low-power, ECG monitoring.

Research on real-time detection system of catheter delivering force in vascular interventional robots / 生物医学工程学杂志

In existing vascular interventional surgical robots, it is difficult to accurately detect the delivery force of the catheter/guidewire at the slave side. Aiming to solve this problem, a real-time force detection system was designed for vascular interventional surgical (VIS) robots based on catheter push force. Firstly, the transfer process of catheter operating forces in the slave end of the interventional robot was analyzed and modeled, and the design principle of the catheter operating force detection system was obtained. Secondly, based on the principle of stress and strain, a torque sensor was designed and integrated into the internal transmission shaft of the slave end of the interventional robot, and a data acquisition and processing system was established. Thirdly, an ATI high-precision torque sensor was used to build the experimental platform, and the designed sensor was tested and calibrated. Finally, sensor test experiments under ideal static/dynamic conditions and simulated catheter delivery tests based on actual human computed tomography (CT) data and vascular model were carried out. The results showed that the average relative detection error of the designed sensor system was 1.26% under ideal static conditions and 1.38% under ideal dynamic stability conditions. The system can detect on-line catheter operation force at high precision, which is of great significance towards improving patient safety in interventional robotic surgery.

Structural design and performance analysis of an auxiliary dining robot / 生物医学工程学杂志

An auxiliary dining robot is designed in this paper, which implements the humanoid feeding function with theory of inventive problem solving (TRIZ) theory and aims at the demand of special auxiliary nursing equipment. Firstly, this robot simulated the motion function of human arm by using the tandem joints of the manipulator. The end-effector used a motor-driven spoon to simulate the feeding actions of human hand. Meanwhile, the eye in hand installation style was adopted to instead the human vision to realize its automatic feeding action. Moreover, the feeding and drinking actions of the dining robot were considered comprehensively with the flexibility of spatial movement under the lowest degree of freedom (DOF) configuration. The structure of the dining robot was confirmed by analyzing its stresses and discussing the specific application scenarios under this condition. Finally, the simulation results demonstrate high-flexibility of the dining robot in the workspace with lowest DOF configuration.

Design, simulation and application of multichannel microfluidic chip for cell migration / 生物医学工程学杂志

Cell migration is defined as the directional movement of cells toward a specific chemical concentration gradient, which plays a crucial role in embryo development, wound healing and tumor metastasis. However, current research methods showed low flux and are only suitable for single-factor assessment, and it was difficult to comprehensively consider the effects of other parameters such as different concentration gradients on cell migration behavior. In this paper, a four-channel microfluidic chip was designed. Its characteristics were as follows: it relied on laminar flow and diffusion mechanisms to establish and maintain a concentration gradient; it was suitable for observation of cell migration in different concentration gradient environment under a single microscope field; four cell isolation zones (20 μm width) were integrated into the microfluidic device to calibrate the initial cell position, which ensured the accuracy of the experimental results. In particular, we used COMSOL Multiphysics software to simulate the structure of the chip, which demonstrated the necessity of designing S-shaped microchannel and horizontal pressure balance channel to maintain concentration gradient. Finally, neutrophils were incubated with advanced glycation end products (AGEs, 0, 0.2, 0.5, 1.0 μmol·L -1), which were closely related to diabetes mellitus and its complications. The migration behavior of incubated neutrophils was studied in the 100 nmol·L -1 of chemokine (N-formylmethionyl-leucyl-phenyl-alanine) concentration gradient. The results prove the reliability and practicability of the microfluidic chip.

Development of Nasal Continuum Minimally Invasive Surgical Robot System / 中国医疗器械杂志

In order to improve the operation difficulties in the narrow space of the nasal maxillary sinus, the nasal continuum minimally invasive surgical robot system is designed. The ball-and-socket joints and NiTiNol tubes are used as the main body of the continuum structure to improve the degree of freedom. The hardware systems and software systems are designed. The security control policies are planned. Finally, the robot confirmed prototype experiments are conducted and the feasibility of continuum robot confirmed through master-slave control experiment and animal experiment.