Biomechanical Study of New Biodegradable Esophageal Stent / 中国医疗器械杂志

The radial force of the degradable esophageal stent before and after degradation is one of the important indicators for effective treatment of esophageal stricture. Based on a combination of in vitro experiments and finite element analysis, this paper studies and verifies the biomechanical properties of a new type of degradable esophageal stent under different esophageal stricture conditions. Under radial extrusion conditions, the maximum stress at the port of the stent is 65.25 MPa, and the maximum strain is 1.98%; The peak values of stress and strain under local extrusion and plane extrusion conditions both appear in the extrusion area and the compression expansion area at both ends, which are respectively 48.68 MPa, 46.40 MPa, 0.49%, 1.13%. The maximum radial force of the undegraded stent was 11.22 N, and 97% and 51% of the maximum radial force were maintained after 3 months and 6 months of degradation, respectively. The research results verify the safety and effectiveness of the radial force of the new degradable esophageal stent, and provide a theoretical basis for the clinical treatment of esophageal stricture.

Mechanism of microglia involved in the pathophysiology of brain white matter hyperintensity / 国际脑血管病杂志

As an important imaging marker of cerebral small vessel disease, white matter hyperintensity is closely associated with the clinical manifestations such as cognitive impairment, gait abnormalities, and urinary incontinence. Current studies have shown that the destruction of blood-brain barrier and inflammation response are the important pathophysiological mechanisms of white matter hyperintensity. As the most common immune cell in the inflammatory response of the central nervous system, microglia activation is the key to the occurrence and development of white matter hyperintensity. This article reviews the pathophysiological mechanisms of microglia involved in brain white matter hyperintensity.

Research on Mathematical Distribution of Failure Time and Engineering Evaluation for Medical Electrical Equipment Based on Operation and Maintenance Data / 中国医疗器械杂志

This study mainly discusses the contents, methods and characteristics of the collection of operation and maintenance data, as well as the establishment and evaluation methods of the distribution model of the failure time of medical electrical equipment. The distribution models of failure time at three levels of medical electrical equipment are established by linear regression method and goodness of fit test:The first is the device level MTBF distribution model, the second is the failure rate distribution model of the failure mode of key components, the third is the calculation model of the influence coefficient of influence factor on the failure mode of key components. This study presents a method of establishing MTBF segment model and implements a calculation model of influence coefficient varying with time.

Simulation Study on Radiated Immunity Test of Active Implantable Medical Device / 中国医疗器械杂志

In the electromagnetic compatibility standards of active implantable medical devices such as ISO 14117,radiated immunity test above 450 MHz frequency is recommended to be carried out in the electromagnetic shielding room.However,different test locations and the shape/size of the shielding room may lead to very different electromagnetic field distribution in the radiation exposure area of the sample,thus affecting the consistency of the test.With the model built by COMSOL software,this paper analyzes the impact of different parameters,such as size of the room and position of torso simulator on the distribution of field intensity,and reaches results about the distribution of field intensity on the torso simulator area under tow sizes of shielding rooms and two typical test positions.The results show that the experimental consistency of the electric field intensity on the surface directly below the center of the antenna is not good enough,which may affect the repeatability of the test.

Exploration of Domestic Medical Electrical Equipment Reliability Promotion Method / 中国医疗器械杂志

The reliability of domestic medical equipment is one of the main factors that restrict the competitiveness of domestic medical devices. It is also an important factor that endangers the safety of patients and a blind spot in safety risk management. By analyzing the core elements of reliability and the situation of domestic medical device industry, this paper sorts out and analyzes the problems existing in the reliability of medical device industry, and puts forward the key points and problems to be solved to improve the reliability of domestic medical equipment products.

Research on Field Strength of Radiated Immunity Test for Active Implantable Medical Devices / 中国医疗器械杂志

In order to compare the radiation immunity test level of ISO 14708 series standards and the domestic and international environmental radiation standards and then to ascertain whether the radiated immunity test level has reached the limit of the radiation strength in the relevant radiation environmental standards, this paper calculated the radiation field intensity and power density according to the radiated immunity test of ISO 14708 standards, and compared with the limit of ICNIRP 1998 and GB 8702-2014.

A Torso Simulator Design for Implantable Nerve Stimulator Test / 中国医疗器械杂志

This paper introduces ISO 14708-3:2017, the new edition of the international standard for implantable neurostimulator, and emphasizes the new requirements in the clause of protection from RF electromagnetic interference. To meet this new requirements, this paper presents a design of torso simulator for the testing of implantable neurostimulator. The design includes volume conductor, electrodes and grids, which can simulate the actual operating environment of implantable neurostimulator in RF electromagnetic interference testing. The torso simulator is verified by performance in the last part of the paper.