| || Amifostine : An effective prophylactic agent against sulphur mustard toxicity
Author : Pathak, Uma ;Raza, S. K.;Vijayraghavan, R. ;Jaiswal, D. K. ;Kumar, P.
Source : Defence Science Journal ; Vol:52(4) ; 2002 ; pp 439-444
Subject : 57.089 Biomedical Sciences ;57 Biological Sciences
Keywords : Amifostine ;Sulphur mustard ;Prophylactic agent ;Radioprotector ;Toxicity ;Alkylating agent
Abstract : Amifostine, S-2-(aminopropylamino) ethylphosphorothioate and two of its analogues have been evaluated as prophylactic agent against SM toxicity. The compounds were administered intraperitoncally (i.p.) at 0.2 LD/sub59 dose in mice 30 min prior to dermal application of SM. The protective efficacy was determined by observing the mortality for 14 days. The protection offered by amifostine was better than its analogues. Subsequent study on time-dependent protection, carried out with amifostine (0.2 LD/sub50, i.p.) provided significant protection when the drug was administered as 30 min pre-treatment and simultaneous treatment against SM at 155 mg.kg/-1 dose (equal to 19-fold LD/sub50). Furthermore, oral administration of amifostine (30 min pre-treatment) showed similar results. These findings suggest that amifostine is a promising prophylactic agent against SM toxicity.
| || Carbon Nanotube-based Cold Cathode for High Power Microwave Vacuum Electronic Devices: A Potential Field Emitter
Author : Verma, P.;Gautam, S.;Pal, S.;Kumar, P.;Chaturvedi, P.;Rawat, J.S.B.S.;Chaudhary, P.K.;Harsh;Basu, P.K.;Bhatanagar, P.K.
Source : Defence Science Journal ; Vol:58(5) ; 2008 ; pp 650-654
Keywords : Carbon nanotubes;Microwwave vacuum electronic devices;Cold cathode;Field emission
Abstract : Carbon nanotubes (CNTs) can be grown in the form of small, sharp spikes capable of carrying very high current densities which suggest great potential application of CNTs as cold cathode in high power microwave vacuum device applications. These cold cathode vacuum microwave devices are expected to be ideally suited for air-borne and space applications. This paper reports the initial efforts made in the development of cold cathode using PECVD grown vertically-aligned matrix of CNTs with uniform height and optimum tip density on silicon substrate. The high aspect ratio (of the order of 10,000) and novel electrical, mechanical, and thermal properties of the CNT are found to be very attractive characteristics for emission of large and stable current densities at reasonably low field. The field emission current voltage characteristics of a typical cathode gave emission current density in excess of 35 mA/cm2 at reasonably low field. The emission current in most of the samples is found to be stable over long period of time but is greatly effected by the vacuum condition during measurement. The initial measured data suggests great promise for achieving high current densities at practical electric fields.