Investigation of the impact of Al mole-fraction on the consequences of RF stress on Al/sub x/Ga/sub 1-x/N/GaN MODFETs

Variations of the low-frequency noise (LFN), power, and dc characteristics of a variety of SiN/sub x/ passivated AlGaN/GaN MODFETs with different values of Al mole-fraction, gate length, and gate drain spacing upon RF stress are investigated. It is experimentally evidenced that the variation of Al mole-fraction (x) of the barrier Al/sub x/Ga/sub 1-x/N layer from 0.2 to 0.4, has no considerable impact on the drain and gate low-frequency noise current characteristics. The most noticeable variation on the device characteristics upon long-term RF stressing has been on the pinch-off voltage. Although no material degradation by increasing the Al mole-fraction has been evidenced through the low-frequency noise data, it is observed that the variation of pinch-off voltage upon RF stressing becomes more important as the Al mole-fraction increases.     

Free vibration and buckling analysis of laminated composite plates using the NURBS-based isogeometric finite element method

An isogeometric finite element method based on non-uniform rational B-splines (NURBS) basis functions is developed for natural frequencies and buckling analysis of thin symmetrically laminated composite plates based upon the classical plate theory (CPT). The approximation of the solution space for the deflection field of the plate and the parameterization of the geometry are performed using NURBS-based approach. The essential boundary conditions are formulated separately from the discrete system equations by the aid of Lagrange multiplier method, while an orthogonal transformation technique is also applied to impose the essential boundary conditions in the discrete eigen-value equation. The accuracy and the efficiency of the proposed method are thus demonstrated through a series of numerical experiments of laminated composite plates with different boundary conditions, fiber orientations, lay-up number, eigen-modes, etc. The obtained numerical results are then compared with either the analytical solutions or other available numerical methods, and excellent agreements are found.     

Fusogenic liposomal formulation of sirolimus: improvement of drug anti-proliferative effect on human T-cells

Context: Fusogenic liposomes are unique delivery vehicles capable of introducing their contents directly and efficiently into the cytoplasm.

Objective: The objective of this study was to evaluate the potential of fusogenic liposomes containing Sirolimus to improve its anti-proliferative effect on T-lymphocyte cells.

Materials and methods: Conventional liposomes containing Sirolimus were prepared from Dipalmitoylphosphatidylcholine (DPPC) and cholesterol using the modified ethanol injection method. To prepare fusogenic liposomes, dioleoylphosphatidylethanolamine (DOPE) was added to the conventional liposome formulation. The liposomes were characterized by their size, zeta potential, encapsulation efficiency percent (EE%) and chemical stability during 6 months. The in vitro release of liposomes, anti-proliferative effect and liposome uptake of both types of liposomes with optimized formulations were studied on human T-lymphocyte cells employing the MTT assay and fluorescein isothiocyanate-loaded liposomes.

Results and discussion: The particle size of the liposomes was evaluated between 138 and 650?nm and mean zeta potential was in the range of ?32.95 to ?45.60?mV. The average EE% of the prepared conventional and fusogenic liposomes were 76.9% and 80.5%, respectively. Liposomal formulations released only 10–20% of encapsulated drug without any burst effect. In vitro immunosuppressive evaluation on T-cells showed that fusogenic liposomes have the best anti-proliferative effects and uptake on T-lymphocyte cell compared to the conventional liposomes.

Conclusion: Our results indicated that fusogenic liposomes can be useful carriers for improving the inhibition of T-cell proliferation.     

Recurrent supra-anastomotic aneurysm following infrarenal aortic repair

A 72-year-old woman presented with a recurrent proximal aortic true aneurysm 7 years after an abdominal aortic aneurysmectomy. It was complicated by a contained rupture into the right psoas. The repair was successfully realized through a thoraco-abdominal approach. A tube graft was interposed between the proximal aorta and the old graft, associated with the reimplantation of the renal arteries. A systemic follow-up of abdominal aortic grafts by reliable diagnostic methods is advocated to provide a timely and appropriate surgical treatment of this major complication.     

Digestion of feed amino acids in the rumen and intestine of steers measured using a mobile nylon bag technique

The disappearance of dry matter (DM), crude protein (CP), and amino acids (AA) in steers after rumen incubation and intestinal passage of alfalfa hay, barley hay, corn silage, barley grain, corn grain, wheat bran, meat meal, fish meal, cottonseed meal, and soybean meal were measured in 3 steers using a mobile nylon bag technique. Ruminal degradation of individual AA differed between feedstuffs. For barley hay and corn silage, the ruminal disappearance of total AA was higher and lower than the other feedstuffs, respectively. The intestinal digestibility of total AA in alfalfa hay was lower than the digestion of CP. The intestinal digestibility of Arg and His was higher than that of total AA in alfalfa hay, meat meal, cottonseed meal, soybean meal, barley hay, and wheat bran. In addition, the intestinal digestibility of Lys was higher than that of total AA in alfalfa hay, meat meal, cottonseed meal, soybean meal, barley hay, corn silage, and wheat bran. The intestinal disappearance of CP in most cases was higher than that of DM. The results indicated that feedstuffs with lower ruminal disappearance of DM, CP, total AA, essential AA, and nonessential AA generally had a higher intestinal disappearance, resulting in a relatively constant total tract disappearance. These results could be used to improve the current system of diet formulation in ruminants.     

Biochemical and rheological characterization of a protease from fruits of Withania coagulans with a milk-clotting activity

A protease from Withania coagulans fruits was evaluated for milk-clotting properties. The optimum temperature and pH for enzyme activity were 70°C and 4, respectively. The protease also exhibited an excellent thermal stability at 60°C for 30 min. Fractional precipitation using ammonium sulfate showed that the 40–50% fraction (F5) possessed the highest milk-clotting activity. The F5 fraction showed a Mw band of 66 kDa by SDS-PAGE. Gel formation was monitored using low amplitude oscillatory rheology at different temperatures. An Arrhenius plot was used to describe the temperature dependence of the gelation rate parameter. Time sweep testing showed that an increase in temperature was accompanied by a decrease in the gelation onset time, a higher gel formation rate, and higher values for final gel strength. W.coagulans fruits have potential for use as a rennet substitute.     

Bortezomib-loaded solid lipid nanoparticles: preparation,characterization, and intestinal permeability investigation

Bortezomib (BTZ), a proteasome inhibitor, is clinically used for the treatment of multiple myeloma and mantle cell lymphoma via intravenous or subcutaneous administration. Since BTZ has limited intestinal permeability, in this study, solid lipid nanoparticles (SLNs) were selected as lipid carrier to improve the intestinal permeability of BTZ. The nanoparticles were prepared by hot oil-in-water emulsification method and characterized for physicochemical properties. Moreover, in situ single-pass intestinal perfusion technique was used for intestinal permeability studies. Mean particle size of the BTZ-loaded solid lipid nanoparticles (BTZ-SLNs) was 94.6?±?0.66?nm with a negative surface charge of –18?±?11?mV. The entrapment efficiency of the BTZ-SLNs was 68.3?±?3.7% with a drug loading value of 0.8?±?0.05%. Cumulative drug release (%) over 48?h, indicated a slow release pattern for nanoparticles. Moreover, the SEM image showed a spherical shape and uniform size distribution for nanoparticles. Also, FTIR analysis indicated that BTZ was successfully loaded in the SLNs. The results of the intestinal perfusion studies revealed an improved effective permeability for BTZ-SLNs with a P_eff value of about threefold higher than plain BTZ solution.