ESHARP: Energy-Efficient and Smart Hierarchical Routing Protocol Based on Smart Slumber for Wireless Sensor Networks

Wireless Personal Communications - This paper proposes a new energy management function intended to be integrated in the Hierarchical Smart Routing Protocol (HSRP) mainly proposed for Wireless...     

RaCH: A New Radial Cluster Head Selection Algorithm for Wireless Sensor Networks

Wireless Personal Communications - This paper presents a radial cluster heads selection mechanism for homogenous wireless sensor networks. It aims to ensure a good load balancing and enhance the...     

Hydrogen exchange between the alkyl hydrogens of 1-amino-5, 5-dimethylhexane and sulfuric acid

The hydrogen exchange between 1-amino-5,5-dimethylhexane and sulfuric acid has been studied. In 97.5 wt.% sulfuric acid the exchange of methyl hydrogens with acidic protons can be observed at 175°C. The exchange of only one hydrogen atom takes place in one activation step.

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1--5,5- . 97,5 . %- . , .

     

Chemical Modification of Saccharomycopsis fibuligera R64 α-Amylase to Improve its Stability Against Thermal, Chelator, and Proteolytic Inactivation

α-Amylase catalyzes hydrolysis of starch to oligosaccharides, which are further degraded to simple sugars. The enzyme has been widely used in food and textile industries and recently, in generation of renewable energy. An α-amylase from yeast Saccharomycopsis fibuligera R64 (Sfamy) is active at 50 °C and capable of degrading raw starch, making it attractive for the aforementioned applications. To improve its characteristics as well as to provide information for structural study ab initio, the enzyme was chemically modified by acid anhydrides (nonpolar groups), glyoxylic acid (GA) (polar group), dimethyl adipimidate (DMA) (cross-linking), and polyethylene glycol (PEG) (hydrophilization). Introduction of nonpolar groups increased enzyme stability up to 18 times, while modification by a cross-linking agent resulted in protection of the calcium ion, which is essential for enzyme activity and integrity. The hydrophilization with PEG resulted in protection against tryptic digestion. The chemical modification of Sfamy by various modifiers has thereby resulted in improvement of its characteristics and provided systematic information beneficial for structural study of the enzyme. An in silico structural study of the enzyme improved the interpretation of the results.