Hydrogels are 3D crosslinked polymer matrices having a colossal tendency to imbibe water and exhibit swelling under physiological conditions without deformation in their hydrophilic network. Hydrogels being biodegradable and biocompatible, gained consideration due to some unique characteristics: responsiveness to external stimuli (pH, temperature) and swelling in aqueous solutions. Hydrogels offer a promising option for various pharmaceutical and biomedical applications, including tissue-specific drug delivery at a predetermined, controlled rate. This article presents a brief review of the recent and fundamental advances to design hydrogels, the swelling and deswelling mechanism, various crosslinking methods and their use as an intelligent carrier in the pharmaceutical field. Recent applications of hydrogels are also briefly discussed and exemplified.
Ribonucleic acid (RNA) silencing, RNA interference (RNAi) or post-transcriptional gene silencing takes place in a variety of eukaryotes and it was discovered firstly in the plants. The RNA silencing process is activated by a trigger from dsRNA predecessor. A very important step in the silencing pathways the conversion of dsRNA into small duplexes of RNA of the representative length and arrangement. Then these small dsRNA monitor RNA silencing by different mechanisms. Post transcriptional gene silencing mechanisms were initially identified as an anti-viral process that give protection to the organisms from the viruses or which inhibit the unsystematic incorporation of transposable components. The basic aim of this review article is to study the mechanism of gene silencing by dsRNA and the roles of certain proteins in cellular post transcriptional RNA silencing machinery and finally we also discuss the RNA silencing as an anti-viral defense mechanism in the plants.
One of the basic requirements for every human being is the availability of clean drinking water, but about 1.1 billion people in the world lacked pure drinking water. Thfere several types of water purification processes used worldwide such as filtration, reverse osmosis, ultraviolet radiation, carbon absorption, but distillation and boiling is considered to be the most reliable among these process. In areas where water resources or tap water is not suitable for drinking without boiling or chemical treatment Water purification, such as distillation, plays an important role in providing clean drinking water. Distillation is the common method usually seen in nature in which the water on earth is heated by sun and then converted into a vapor (evaporation) and rises, leaving behind contaminants, to form clouds. The vapor converts back to water after it cools when the temperature in the upper atmosphere drops. Water is essential for life. The origin and continuance of mankind is based on water. Developing countries face a significant problem in the supply of drinking water. With the increasing population and industrial growth and agricultural activities causes depletion of many fresh water resources due to rapid increase in need for energy and to overcome environmental concerns much attention is focused on renewable energy resources. Solar distillation is one of the non-conventional methods to desalinate brackish water or sea water. This work focuses on an experimental investigation by comparing the performance of two solar stills such as rectangular shape and basin shape solar still, with photo catalyst and reflector base solar still. The comparative performance study is analyzed for the same weather conditions with different design parameters and some important conclusions were assigned.
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