Addition of two full-thickness simple interrupted sutures to standard incisional gastropexy increases gastropexy biomechanical strength.

OBJECTIVE: To compare the acute strength (failure load and work to failure) of standard incisional gastropexy (SIG) and modified incisional gastropexy (MIG). ANIMALS: 37 pig cadavers. PROCEDURES: Stomachs and right abdominal walls were harvested from pigs euthanized for reasons unrelated to this study. The tissues were stored in lactated Ringer's solution overnight in a 5 °C cooler. Matching body wall and stomach tissue pairs were randomized and divided into 2 groups, on which either SIG or MIG was performed the following day. The MIG technique was identical to SIG except 2 additional simple interrupted sutures, 1 cranial and 1 caudal to the continuous suture line, were placed full thickness into the stomach to ensure engagement of the submucosa. After gastropexy, the samples underwent biomechanical testing. Information regarding change in position and load was generated by the MTESTQuattro software. Mode of failure was examined after the procedure was complete. RESULTS: The MIG had higher failure load and work to failure compared to SIG. All failures were caused by gastric tissue tearing. CLINICAL RELEVANCE: The MIG is biomechanically superior to SIG and may provide more security than SIG during healing. However, clinical study is needed to ascertain if there is a difference in gastropexy failure and complications between these 2 techniques.

Thermal and Visual Observation of Water and Acetone Oscillating Heat Pipes.

A visual and thermal experimental investigation of four oscillating heat pipes (OHPs) was conducted to observe fluid flow of liquid plugs and vapor bubbles in the OHP and its effect on the temperature distribution and heat transfer performance in an OHP. These four OHPs consist of an open loop water OHP, an open loop acetone OHP, a closed loop water OHP, and a closed loop acetone OHP. These copper OHPs were constructed identically with all six turns in the same plane. They were constructed out of 1.65 mm inner diameter copper tubing and copper heat spreading plates in the evaporator and condenser regions. The heat pipes were charged at a filling ratio of about 50%. The results show that the acetone OHP at low power performs better than the water OHP, while at high power the water OHP exceeds the acetone OHP. The experimental results show that both the acetone and water closed loop OHPs had reduced movement in the connecting turn between the two sides. However, in the water closed loop OHP, this prevented circulation altogether. Comparing the water closed loop OHP to the water open loop OHP, their flow patterns were similar. Therefore, improving the flow in this turn should increase the closed loop OHP's performance.

Heat Transport Capability and Fluid Flow Neutron Radiography of Three-Dimensional Oscillating Heat Pipes.

An experimental investigation into the parameters affecting heat transport in two three-dimensional oscillating heat pipes (OHPs) was implemented. A three-dimensional OHP is one in which the center axis of the circular channels containing the internal working fluid do not lie in the same plane. This novel design allows for more turns in a more compact size. The OHPs in the current investigation is made of copper tubings (3.175 mm outside diameter, 1.65 mm inside diameter) wrapped in a three-dimensional fashion around two copper spreaders that act as the evaporator and condenser. The two OHPs have 10 and 20 turns in both the evaporator and condenser. The 20-turn OHP was filled to 50% of the total volume with a high performance liquid chromatography grade water. Transient and steady state temperature data were recorded at different locations for various parameters. Parameters such as heat input, operating temperature, and filling ratio were varied to determine its effect on the overall heat transport. Neutron radiography was simultaneously implemented to create images of the internal working fluid flow at a rate of 30 frames per second. Results show the average temperature drop from the evaporator to condenser decreases at higher heat inputs due to an increase in temperature throughout the condenser region due to greater oscillations. These large oscillations were visually observed using neutron radiography. As the operating temperature is increased, the thermal resistance is reduced. A decrease in filling ratio tends to create more steady fluid motion; however, the heat transfer performance is reduced.