Lipase-catalyzed Reactions at Interfaces of Two-phase Systems and Microemulsions

This work describes the influence of two polar lipids, Sn-1/3 and Sn-2 monopalmitin, on the activity of lipase in biphasic systems and in microemulsions. In previous communications, we have shown that Sn-2 monoglycerides can replace Sn-1,3 regiospecific lipases at the oil–water interface, causing a drastically reduced rate of lipolysis. We here demonstrate that even if the lipase is expelled from the interface, it can catalyze esterification of the Sn-2 monoglyceride with fatty acids in both macroscopic oil–water systems and in microemulsions, leading to formation of di- and triglycerides

Computer-Aided Solvent Screening for Biocatalysis

A computer-aidedsolventscreening methodology is described and tested for biocatalytic systems composed of enzyme, essential water and substrates/products dissolved in a solvent medium, without cells. The methodology is computationally simple, using group contribution methods for calculating constrained properties related to chemical reaction equilibrium, substrate and product solubility, water solubility, boiling points, toxicity and others. Two examples are provided, covering the screening of solvents for lipase-catalyzed transesterification of octanol and inulin with vinyl laurate. Esterification of acrylic acid with octanol is also addressed. Solvents are screened and candidates identified, confirming existing experimental results. Although the examples involve lipases, the method is quite general, so there seems to be no preclusion against application to other biocatalyst

Affect of handover on the performance of routing protocols in WiMax

With the increasing demand for mobile broadband service, and the expectations of an enriched end user experience expanding beyond just homes and offices, the best available network technology in the present market is Worldwide Interoperability for Microwave Access (WIMAX). It has a great potential to become commercially successful due to its high throughput, large coverage and low cost. In this study, a simulation of a WIMAX network with mobility is performed. The network scenario for the simulation replicates a practical, real-world network as closely as possible. In this scenario, the behavior of routing protocols under the influence of WIMAX tower handovers is examined. The routing protocols analyzed are Destination Sequenced Distance Vector (DSDV), Ad Hoc On Demand Distance Vector (AODV) and Dynamic MANET On Demand (DYMO). The protocols are compared on the basis of throughput and average end-to-end delay. The effect of parameters such as network load and network size on the performance of the routing protocols is also examined. This study demonstrates that the performance of a routing protocol is clearly dependent on the application for which it is used. Table driven routing protocols such as DSDV perform poorly in networks with mobility. AODV performs well in large networks with low to medium loads, while DYMO performs well in both small networks and large networks with heavy loads