Oral Nanoparticulate Atorvastatin Calcium is More Efficient and Safe in Comparison to Lipicure<Superscript>®</Superscript> in Treating Hyperlipidemia

Atorvastatin calcium (AC) is a second-generation 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor approved for clinical use as a lipid lowering agent. AC, the world's best selling drug is associated with poor oral bioavailability and serious adverse effects like rhabdomyolysis on chronic administration. A biodegradable nanoparticulate approach was introduced here with a view to improving the efficacy and safety of AC. Poly lactide-co-glycolic acid (PLGA) nanoparticles containing atorvastatin calcium were prepared using two stabilizers i.e. didodecyl dimethyl ammonium bromide (DMAB) and Vitamin E tocopheryl polyethylene glycol 1000 succinate (Vit E-TPGS) using a co-solvent approach by emulsion-diffusion-evaporation method. AC loaded PLGA nanoparticles prepared using DMAB and Vit E-TPGS were found to be 120.0 +/- 4.2 nm and 140.0 +/- 1.5 nm (z-average) in size respectively. In vitro release studies at pH 7.4 revealed a zero order release profile for nanoparticles. Efficacy and safety parameters of the prepared nanoparticles against marketed formulation were evaluated in high fat diet fed (hyperlipidemic) rats. It was found that atorvastatin calcium nanoparticles were equally effective in comparison to Lipicure, at a 66%-reduced dose in treating the hyperlipidemia characterized by alterations in PTC, LDL-C, VLDL-C, HDL-C, PTG and PGL in the high fat diet fed rats. On the other hand, when evaluated for safety, nanoparticulate formulation showed no/negligible myotoxicity characterized by lower PC, BUN, CK, LDH and AST levels in comparison to the marketed formulation.     

On-line monitoring of tool wear in turning operation in the presence of tool misalignment

A vision system using high-resolution CCD camera and back-light was developed for the on-line measurement of nose wear of cutting tool inserts. Initial study showed that the system is sensitive to several factors in the work environment such as misalignment of cutting tool, presence of micro-dust particles, vibration and intensity variation of ambient light. An algorithm using Wiener filtering, median filtering, morphological operations and thresholding was developed to decrease the system error caused by these factors. A conforming method was used to overcome misalignment of the tool insert during offline and on-line measurement. The algorithm, combined with a subtraction method, was applied to measure the nose wear area of the inserts under different machining conditions.     

Novel high-voltage silicon-on-insulator MOSFETs

Novel lateral RESURF high voltage SOI MOSFETs capable of withstanding up to 400V are presented in this paper. The design optimization, fabrication and experimental results obtained on these devices are also presented. The devices are implementable using a CMOS-SOI compatible process.     

Plasma levels of oestriol-17 beta, oestriol and human placental lactogen during bed rest

Plasma unconjugated oestradiol-17 beta, total oestriol and human placental lactogen levels were measured in twelve healthy volunteers admitted for bed rest in the last trimester of pregnancy. No significant alteration in levels was observed.     

Evidence of irradiation‐induced crosslinking in miscible blends of poly(vinyl chloride)/epoxidized natural rubber in presence of trimethylolpropane triacrylate

Electron‐beam initiated crosslinking of a poly(vinyl chloride)/epoxidized natural rubber blend (PVC/ENR), which contained trimethylolpropane triacrylate (TMPTA), was carried out over a range of irradiation doses (20–200 kGy) and concentrations of TMPTA (1–5 phr). The gelation dose was determined by a method proposed by Charlesby. It was evident from the gelation dose, resilience, hysteresis, glass‐transition temperature (T_g), IR spectroscopy, and scanning electron microscopy studies that the miscible PVC/ENR blend underwent crosslinking by electron‐beam irradiation. The acceleration of crosslinking by the TMPTA was further confirmed in this study. Agreement of the results with a theory relating the T_g with the distance between crosslinks provided further evidence of irradiation‐induced crosslinking. The possible mechanism of crosslinking induced by the irradiation between PVC and ENR is also proposed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1914–1925, 2001     

The effect of biological studies of polyester composites filled carbon black and activated carbon from bamboo (Gigantochloa scortechinii)

The development of composites using various filler material increased significantly nowadays. Composite materials need to implement the biological and mechanicals impact in their life cycle. The carbon black (CB) and activated carbon (AC) from bamboo (Gigantochloa scortechinii) were used as filler in polyester composites. CB and AC were pyrolized to 700°C and activated with ZnCl₂. The composites were prepared with 40% filler loading. The degradation of the composites CB and AC (mechanical properties) to the soil burial test was determined. Tensile, flexural, impact and mass changes of the buried samples were investigated. The deterioration of the samples affected by the biological attack was confirmed by SEM studies. The assessment was done after 0, 3, 6, and 12 months of the biological exposure and the results were compared with the composites filled CaCO₃ (commercial filler) and cast polyester resin (as control). POLYM. COMPOS. 28:6–14, 2007. © 2007 Society of Plastics Engineers     

A transgressive brown rice mediates favourable glycaemic and insulin responses

BACKGROUND: We evaluated glycaemic response of a brown rice variant (BR) developed by cross‐breeding. Subjects (n = 9) consumed 50 g carbohydrate equivalents of BR, white rice (WR) and the polished brown rice (PR) in comparison to 50 g glucose reference (GLU) in a cross‐over design. Plasma glucose and insulin at 0, 15, 45, 60, 90, 120 and 180 min were measured and incremental area under the curve (IAUC) and indices for glucose (GI) and insulin (II) calculated. RESULTS: BR compared to PR or WR produced the lowest postprandial glycaemia (GI: 51 vs 79 vs 86) and insulinaemia (II: 39 vs 63 vs 68) irrespective of amylose content (19 vs 23 vs 26.5%). Only BR was significantly different from GLU for both plasma glucose (P = 0.012) and insulin (P = 0.013) as well as IAUC_glu (P = 0.045) and IAUC_ins (P = 0.031). Glycaemic and insulinaemic responses correlated positively (r = 0.550, P < 0.001). Linear trends for IAUC_glu and IAUC_ins indicated a greater secretion of insulin tied in with a greater glycaemic response for WR (r² = 0.848), moderate for PR (r² = 0.302) and weakest for BR (r² = 0.122). CONCLUSION: The brown rice variant had the lowest GI and II values but these advantages were lost with polishing. Copyright © 2011 Society of Chemical Industry     

Bandwidth Partitioning and SINR Threshold Analysis of Fractional Frequency Reuse in OFDMA Cellular Networks for Real Time and Best Effort Traffic

To achieve high capacity in cellular networks, frequency reuse factor of unity is used. However, it suffers from heavy co-channel interference at cell edge regions. This leads to poor Signal to Interference plus Noise Ratio (SINR) and hence poor performance. fractional frequency reuse (FFR) is one of the methods being considered to improve cell edge performance. In this work we present the impact of SINR threshold and bandwidth partitioning on the successful deployment of FFR scheme. We have considered both real time (RT) and best effort (BE) traffic. In FFR, the total frequency resource is divided logically into cell center and cell edge user bands. However, while frequency resource is partitioned into two segments, the amount of bandwidth required by cell center and cell edge users is quite different and influences the system performance. We developed the semi analytical approach to evaluate the average bandwidth required by cell center and edge band users. From the analysis and simulation results it is seen that while grade of service (GoS) fair based method of choosing bandwidth partitioning ratio is best for RT traffic, while the only feasible method for BE traffic is dividing the bandwidth based on probability of a user to be in a given band which we termed as ‘Probability’ method.     

Bubble-induced circulation and associated boundary heat transfer

The mechanism of heat transfer from a bubbling liquid pool to an inclined side wall is considered. The process is relevant to the question of Mark-I liner melt-through due to contact with a high-temperature melt of reactor core materials, the bubbling being due to the decomposition of the concrete floor. We demonstrate experimentally that the recirculation caused by the two-phase lift creates a single-phase (liquid) boundary-layer flow along the inclined boundary which is responsible for heat transfer. An initial attempt to analytically quantify this process is also presented.