Randomized study on the safety and efficacy of dual-axis rotational versus standard coronary angiography in the Chinese population

Background Dual-axis rotational coronary angiography （DARCA） was developed as an innovative adaptation of rotational angiography （RA）, but it requires a longer coronary injection compared to standard coronary angiography （SA）. As the body of the average Chinese patient is smaller than that of most western patients, with the same contrast injection time, the risk of complications from the contrast agent is increased in this population. The purpose of this study was to assess the clinical safety and efficacy of DARCA in the diagnosis of coronary artery disease （CAD） in the Chinese population by directly comparing it to SA. Methods Two hundred Chinese patients were randomized to either the SA group （n=100） or DARCA group （n=100）. Contrast utilization, radiation exposure and procedure time were recorded for each modalities. Blood pressure （BP）, heart rate （HR） pre and post injection symptoms and any arrhythmias were recorded. Results Compared to the SA group, there was a 42% reduction in contrast utilization, 55% reduction in radiation exposure and a 31% shorter procedure time in the DARCA group. In both groups, there were slight declines in the systolic BP values in the left coronary artery （LCA） post injection （P 〈0.01）. Moreover, post injection HRs for the LCA were also reduced in the DARCA group （P 〈0.01）. But all of these changes were small, transient and without clinical importance. Only one patient （1%） in the DARCA group had an attack of ventricular tachycardia immediately post injection and it resolved by itself during LCA angiography. No arrhythmias occurred in the SA group. Conclusion DARCA is a safe, efficient, and clinically comparable alternative to SA in the diagnosis of coronary artery disease in the Chinese population with less contrast utilized, which is less radiation exposure and a shorter procedure

Environmental simulation platform and its application to geodesic instruments for a performance study

In this study,an environmental simulation platform(ETS-02)was constructed for high-precision geodesic instruments(e.g.,absolute/relative gravimeters and inclinometers),to test the disturbances caused by environmental fl uctuations.The outer layer of the platform was constructed with two sets of rectangular electromagnetic coils,which generated the required magnetic fi eld when current was applied.The inner layer was a closed cabin in which radiators were distributed such that the temperature of the experimental space inside the cabin could be controlled,by energy exchange between the radiators and a thermal controller through the fl owing liquid.A high-precision hexapod was used to simulate the tilt-related eff ect.The platform was capable of adjusting temperatures within a dynamic range of 0℃-70℃ at a resolution of 0.01℃.The noise of the power-spectrum density when the cabin was set to room temperature was measured as 0.03℃/Hz^(1/2) at 1 mHz.The magnetic field simulation had a dynamic range of±300μT and stability of 20 nT.The resolution of the ground-tilt simulation was 1 arc s.The inner space of the platform had a volume of approximately 5 m^(3),which is sufficient for most types of instruments to be tested for a general environmental coupling effect.To illustrate the application of the platform,a dual-axis inclinometer was built and tested carefully with the platform,and the accuracy of the calibration factors was found to be signifi cantly improved.

A dual-axis chewing simulator for in vitro wear test of dental restoration materials

The wear rate of dental restoration materials on fixed, removable, and implant prostheses is important in the maintenance of cuspate form, masticatory efficiency and occlusal stability. Many permanent restoration materials such as composite, amalgam, gold, or porcelain show enough resistance to wear, but the wear rates of newly developed materials are generally unknown. To evaluate the wear rate of these dental materials, in vivo (clinic) and in vitro methods can be used. Since in vivo investigations are expensive, time consuming, and difficult to standardize, various in vitro methods have been developed. The use of a chewing machine is considered the best method, because a variety of wear mechanisms, temperature changes, and chemical effects of food and drink can be simulated simultaneously. This paper describes a dual axis chewing simulator for in vitro wear test of dental restoration materials. It consists of 8 test chambers, two stepper motors and related mechanism, a hot and cool water circle system, and a control unit. In the chambers, samples and antagonists make chewing movements vertically and Albert Ludwigs University, School of dentistry, Freiburg, Germany (Lü XY, Kern M and Strub JR) horizontally driven by the stepper motors so that the gnashing and slippage of two teeth against each other is simulated. A weighted test object is programmed to collide with a sample under precise operator control. The antagonists strike against the samples at various speeds from a slow nudge to snapping. Sample holders are designed for installation of varying samples, from single teeth to complete dentures. Two baths, six valves, and a group of pipes are used for the thermocycling. The machine can simulate various chewing modes in the mouth, including fully programmable thermal water cycling between 5℃ and 60℃ The control unit consists of a computer system with a built in specific program. Important operations such as “Start”, “Zero point”, and “Stop” are carried out by pressing the function keys on the front board of the unit. During the programming process and the simulation, several test modes and relevant test parameters are shown on the monitor. The control unit is connected via a series of interfaces to different controlled parts of the machine, such as the stepper motors and the pumps of cool and warm water.