Sliding mode control of a bioreactor

In this paper, sliding mode control (SMC) of a bioreactor is considered and is compared with PID control. The magnitude of the error in SMC is found to be lower than that in PID control. Moreover, the magnitudes of cells and nutrients were very close to the selected reference values in SMC, whereas they were quite different in PID control. Overall, SMC was more robust against disturbances and had better performance than PID control.     

Force analysis of bearings on a modified mechanism using proposed recurrent hybrid neural networks

Due to different load conditions on four-bar mechanisms, it is necessary to analyze force distribution on the bearing systems of mechanisms. A proposed neural network was developed and designed to analyze force distribution on the bearings of a four bar mechanism. The proposed neural network has three layers: input layer, output layer and hidden layer. The hidden layer consists of a recurrent structure to keep dynamic memory for later use. The mechanism is an extended version of a four-bar mechanism. Two elements, spring and viscous, are employed to overcome big force problem on the bearings of the mechanism. The results of the proposed neural network give superior performance for analyzing the forces on the bearings of the four-bar mechanism undergoing big forces and high repetitive motion tracking. This continuation of simulation analysis of bearings should be a benefit to bearing designers and researchers of such mechanisms.     

Effects of the number of pedicles on perfusion and survival of venous flaps: an experimental study in rabbits

Venous flaps are new tools for reconstructive surgery; however, the survival mechanisms of these flaps are not clearly known. This study compares the effects of the number of pedicles in venous flaps and studies the perfusion of these flaps. In the rabbit ear composite tissue venous flap model without the underlying bed and perivenous areolar tissue, three groups with a different number of pedicles were created. The groups consisted of single-pedicled, two-pedicled, and three-pedicled venous flaps. Radioactive tracer studies with technetium 99m were undertaken to assess inflow and drainage. The venous pressure in each pedicled vein and pressure gradients were also documented between the venous pedicles. All single-pedicled venous flaps became necrotic. The mean viable flap area was 40.5% for the two-pedicled venous flaps, 75.8% for the three-pedicled flaps, and 94.1% for the axial-pattern control flaps. Inflow and drainage of the radioactive substance in the three-pedicled venous flaps were better than the two-pedicled venous flaps, but the axial-pattern control flaps were superior to both. We conclude that although venous flaps are still not as reliable as conventional flaps, increasing the number of pedicles affected flap survival positively, and venous flap perfusion occurred due to pressure gradients between flap pedicles.     

Silica-based monodisperse PdCo nanohybrids as highly efficient and stable nanocatalyst for hydrogen evolution reaction

Addressed herein, a highly active and stable nanohybrid has been synthesized for hydrogen production. The newly prepared nanocatalysts are silica-based palladium-cobalt nanohybrid structures (PdCo@SiO₂ nanohybrid) (3.82 ± 0.37 nm). The prepared nanohybrids were fully identified with the help of different analytical techniques such as UV-Vis (Ultraviolet-Visible spectroscopy), XPS (X-ray photoelectron spectroscopy), TEM (Transmission electron microscopy), XRD (X-ray diffraction) and HR-TEM (High-resolution transmission electron microscopy) analyses. This prepared nanohybrid was quite successful in the production of hydrogen from DMAB in ambient conditions (TOF: 108.27 h^?1). By the way, it was observed that the DMAB was converted entirely to the product at room temperature with the help of PdCo@SiO₂ nanohybrid. Moreover, monodisperse PdCo@SiO₂ nanohybrid has shown outstanding reusability performance even after 4th usage in the same reaction. As a result, it can be said that the prepared nanohybrid is highly efficient, stable and durable nanocatalyst for the dehydrocoupling of dimethylamine-borane.     

Ischemia/reperfusion injury in flow-through venous flaps

This study was designed to test the activity and feasibility of 5'-deoxy-5-fluorouridine (5'-DFUR) and cisplatin combination therapy in the treatment of advanced gastric cancer. Nineteen patients with inoperable and/or metastatic gastric cancer, which was histologically proven, were orally administered 5'-DFUR 1,200 mg/m2 on days 1 to 4 and days 15-18 combined with 70 mg/m2 of cisplatin being repeated every 4 weeks. Five partial responses (PRs) were achieved. Seven patients had stable disease and 6 progressed on therapy. The overall response rate was 27.7% (95% confidence interval: 9.69% to 53.5%). The median survival duration of all 18 patients was 25 weeks (9-64). The majority of patients had WHO grade I/II toxicity, but there was no treatment-related death. These data support that the combinations of oral 5'-DFUR and cisplatin are well tolerable and have a moderate activity with low toxicity in the treatment of advanced gastric cancer.