Hand-Powered Inertial Microfluidic Syringe-Tip Centrifuge

Conventional sample preparation techniques require bulky and expensive instruments and are not compatible with next-generation point-of-care diagnostic testing. Here, we report a manually operated syringe-tip inertial microfluidic centrifuge (named i-centrifuge) for high-flow-rate (up to 16 mL/min) cell concentration and experimentally demonstrate its working mechanism and performance. Low-cost polymer films and double-sided tape were used through a rapid nonclean-room process of laser cutting and lamination bonding to construct the key components of the i-centrifuge, which consists of a syringe-tip flow stabilizer and a four-channel paralleled inertial microfluidic concentrator. The unstable liquid flow generated by the manual syringe was regulated and stabilized with the flow stabilizer to power inertial focusing in a four-channel paralleled concentrator. Finally, we successfully used our i-centrifuge for manually operated cell concentration. This i-centrifuge offers the advantages of low device cost, simple hand-powered operation, high-flow-rate processing, and portable device volume. Therefore, it holds potential as a low-cost, portable sample preparation tool for point-of-care diagnostic testing.

An air-locking port and high-flow nasal cannula in non-intubated uniportal video-assisted thoracic surgery for pneumothorax with pulmonary dysfunction: a case report

Background Non-intubated video-assisted thoracic surgery is a therapeutic option for intractable secondary spontaneous pneumothorax in patients who are poor candidates for surgery with endotracheal intubation under general anesthesia. However, intraoperative respiratory management in this surgery is often challenging because of hypoxia caused by surgical pneumothorax. Case presentation A 75-year-old man with idiopathic pulmonary fibrosis who had been on home oxygen therapy underwent non-intubated uniportal video-assisted thoracic surgery for intractable spontaneous pneumothorax. During the operation, oxygen was administered using a high-flow nasal cannula at a high flow rate. An air-locking port for single-incision surgery was used to minimize the inflow of air into the pleural cavity. The intrapleural air was continuously suctioned through the chest tube. The air-leak point was easily identified and closed using ligation. Oxygenation was satisfactory throughout the operation. Conclusions Non-intubated uniportal video-assisted thoracic surgery for secondary spontaneous pneumothorax with an air-locking port, continuous pleural suction, and high-flow nasal cannula may achieve satisfactory intraoperative oxygenation in patients with respiratory dysfunction. The intrapleural space can be feasible for surgical manipulation without surgical pneumothorax in non-intubated video-assisted thoracic surgery even when supplied with oxygen at a high flow rate using a high-flow nasal cannula.

Pumping Schedule Optimization in Acid Fracturing Treatment by Unified Fracture Design

Acid fracturing simulation is used widely to optimize carbonate reservoirs and improve acid fracturing treatment performance. In this study, a method was used to minimize the risk of the acid fracturing treatment. First, optimal fracture geometry parameters with UFD methods are calculated. After that, design components change as long as fracture geometry parameters reach their optimal values. The results showed a high flow rate needed to achieve optimal fracture geometry parameters with increasing acid volume. Sensitivity analysis was performed on controllable and reservoir parameters. It observed that a high flow rate should be applied for a low fluid viscosity to achieve the optimization goals. Straight acid reaches optimal conditions at a high flow rate and low volume. These conditions for retarded acids appear only at a low flow rate and high volume. The study of the acid concentration for gelled acid showed that as it increased, the flow rate and volume increased. Besides, for low permeability formation, a large fracture half-length and small fracture width are desirable. In this case, a higher flow rate will be required. The sensitivity analysis showed that the optimum flow rate and acid volume increase and decrease for the high Young's modulus. The effect of closure stress was also investigated and observed for a sample with high closure stress, low flow rate, and high acid volume are required.