Articles

In this review the importance of chirality in nature is highlighted considering the synthesis of enantiomerically pure compounds in the form of entioenriched amines which have immense pharmaceutical importance, Different strategies are considered here such as enantioselective reduction of imines, chiral pool approach, imine and enamide synthesis, stereoselective conversion of prochiral substrates to enantiopure compounds, enantioselective reduction of enamides, enantioselective imine reduction using organocatalyts and chiral auxiliary approach. Reductive amination is found to be an important strategy to synthesize chiral primary amines. The pros and cons of each strategies are discussed in this review in details. This will be helpful to researchers working in this field to design and plan their future activities which will benefit the society as a whole.

With improvement of civilization, vehicles have become a part and parcel of everyday life.Geographical locations, unavailability of commodities and essential services, requirement of time management in fast paced urban life has proved the necessity of using fossil fuel driven vehicles. Oneof the adverse effects of using vehicle in a non-scientific and uncontrolled way is air pollution.Uncontrolled utilization of fossil fuel is caused due to incomplete combustion of fuel. Although qualityof fuel and engines is upgrading day by day, but negligence of proper maintenance of vehicles by owners is also increasing. This paper aims at creating a small low cost prototype that not only alarm the user about the over pollution level but also compels to take necessary action before using the vehicle.

Mutual coupling arises in an antenna array because of 1. Signal leakage via conducting currents on the metallic background or surface wave along substrates 2. Leakage received from space between antenna elements. The first one can be suppressed by changing the distribution of surface currents. But in the 2nd case the radiation-leakage caused coupling can be minimized by conventional approaches using circuit manipulation. In this research work, we propose and design a decoupling module, which is planer frequency-selective surface structure. FSS structure has the ability to suppress the surface wave propagation by providing an extra coupling path which will oppose the signal goes directly from element to element. In this design it has been observed that after implementing FSS structure between antenna elements, it causes significant suppression of mutual coupling with a reduction of more than 50dB at the designed frequency of 3.7GHz.