OBJECTIVETo evaluate the shaping ability of two nickel-titanium rotary systems (ProTaper and Hero642) in simulated S-shaped canals.

METHODSThirty simulated S-shaped canals were randomly divided into three groups and prepared by ProTaper, Hero642, ProTaper combined with Hero642 respectively. All the canals were scanned before and after instrumentation, and the amount of material removed in the inner and outer wall and the canal width after instrumentation were measured with a computer image analysis program.

RESULTSThere was significant difference in the amount of material removed at the inner side of apical curvature and outer side of apex between ProTaper combined with Hero642 and ProTaper files (P < 0.05) at the same tip size. The inner and outer wall of the canals were evenly prepared by ProTaper combined with Hero642, and the taper of canals were better than those prepared by Hero642.

CONCLUSIONSProTaper combined with Hero 642 had better shaping ability to maintain the original shape and could create good taper canals in the simulated S-shaped canal model.

Dental Alloys ; Dental Instruments ; Dental Models ; Dental Pulp Cavity ; Equipment Failure ; Nickel ; Orthodontic Appliance Design ; Root Canal Preparation ; instrumentation ; methods ; Titanium

Digital potentiometers have been used in medical instruments. This paper describes the structure and principle of a digital potentiometer, especially its interfacing with a single chip processor and its programming.
Computers ; Equipment Design ; Equipment and Supplies

The traditional medical instrumentation is now not suited for the transformation of the present healthcare model. It's an attempt to make a breakthrough on traditions to develop wearable sensors/systems. Five articles about wearable technology are selected by this special topic. And our aim is to inspire the designers of medical devices to grasp the chance and to take a vigorous action on innovatory developments, so as to satisfy the huge requirements of the healthcare market, and to open a new era of the medical device industry.
Clothing ; Equipment Design ; Equipment and Supplies

The flushing pump which is applied to clean operative wound has no temperature controlling function up to now, and doctors have to prepare the flushing fluid that has previously been warmed. The flushing pump system with medical constant temperature designed in our laboratory can absorb flushing fluid at the room temperature, and then eject flushing fluid with the temperature in accordance with the requirements of operations at a controlled constant flow rate. The system combines flow rate control with temperature control functions. The flushing pump system includes flushing part, temperature controlling part, key inputting part, liquid crystal displaying part and exceptional situation monitoring part. The present paper introduces the design method and principle of each part of the system at first, and then gives the debug method of all the system parameters. Finally the paper discusses the performance of the system according to the result of the experiment.
Equipment Design ; Equipment and Supplies ; Temperature

Since 1995, four different types of artificial heart pumps and artificial valvo-pumps have been developed in Jiangsu University of China. Three types of heart pumps and valvo-pumps have been applied in animal experiments in University Texas, Medical Branch, USA and in Zhenjiang No.1 People's Hospital of China. The recently-developed UJS-IV pump is a totally implantable trans-ventricular and cross-valvular pump for emergercy treatments.
Equipment Design ; Heart Valve Prosthesis ; Heart, Artificial ; Heart-Assist Devices

This article reviews the recent progress of the finite element analysis (FEA) researches focusing on various expansion types, fatigue durability and the flexibility of the stents.
Equipment Failure Analysis ; Finite Element Analysis ; Prosthesis Design ; Stents

An auto-retractable self-disable safety syringe is introduced. The product mainly consists of barrel, plunger hander, needle holder, spring and needle cap. After injection, the clasp on top of plunger hander will be jammed with the outshoot of needle holder, meanwhile, the plunger hander tip expands the stop structure and consequently the compression spring pulls the needle and needle holder back into plunger hander. The technical parameters of present syringe such as break force, needle holder push out force and plunger hander lock force are very stable while working. With simple structure, reasonable design, easy manufacture and assemble, this product can been widely used in relevant area.
Disposable Equipment ; Equipment Design ; Equipment Safety ; Syringes

The effects of operational variables and reactor configurations (e.g. diameter of draft tube and the number of static mixers) on energy loss in modified airlift bioreactor were investigated at the first time. The results showed that improving the structure of draft tube could reduce energy loss in the bioreactor. When the diameter of draft tube and the number of static mixers were 4.0cm and 39, respectively, the total energy loss in the modified bioreactor was the least among all the configurations and 23.6% less than that of the conventional counterpart at the same air flowrate. The energy consumption for aeration was the smallest (43.9% less than that of the conventional counterpart) when the diameter of draft tube and the number of static mixers were 5.5cm and 13, respectively. The highest energy dissipation (70% - 80%) occurred in the riser, the bottom zone (about 20%) took the second place and the separator (less than 10%) took the third place. The energy dissipation in the downcomer was neglectable under the conditions in the research. When the energy loss per unit volume was considered, bottom zone stood the first place. It was implied that the riser was the most important zone to cut down the energy loss of the bioreactor and some attention should also be paid to the bottom zone.
Bioreactors ; Equipment Design

The paper designed the portable free hemoglobin detector using spectrophotometry, which determines the concentration of free hemoglobin. The device has features of portability, compact and precise. It can evaluate the quality of blood products instantly and effectively.
Equipment Design ; Hemoglobinometry ; instrumentation

This article describes the design and development of an ultrasonic power meter which is consist of an electronic balance, a practice target, an acoustic enclosures and a blocking. The electronic balance mounted on the blocking is linked with the practice target by connecting rod. By adjusting the blocking makes the practice target suspended above ultrasound probe, and then the ultrasonic power can be measured. After initial tests, the ultrasonic power meter performanced with good stability and high precision.
Equipment Design ; Ultrasonics