Volume 16, Issue 1, 2016 January-March

Volume 16, No 1 Pages:
2016 January-March Articles: 7

Petrography and heavy minerals as tools for reconstruction of provenance and depositional environment of Bhuban sandstones in Aizawl, Mizoram

Mizoram is entirely covered by sedimentary successions of variable sand-silt-shale ratio. The predominating bed comprises of Surma Group of rocks, and Bhuban Formation being the dominating strata. The present study area of eastern anticlinal limbs of the Aizawl city are made up of thick succession of Bhuban Formation of Surma Group dipping towards east with strike of approximately N-S direction. The present research aims to find out the nature of provenance and the environment of deposition of the sediments on the bases of petrography of the sandstones and heavy minerals present. The petrography indicate presence of quartz, lithic fragments, feldspar, micas, opaque minerals bind together by siliceous, ferruginous and carbonate cements. The heavy minerals comprises of garnet, augite, zircon, rutile, staurolite, sillimanite, kyanite, hypersthene, hornblende, chlorite, tourmaline and apatite. It is found that the sediments of sandstones are derived most probably from the Himalayan Orogenic fold belt and the Indo-Burmese Collision Zones, and the sediments bein

Thermochemical studies of thorium(IV) and zirconium(IV) tetrabenzoates

Thermochemical studies of metal compounds of ‘s’ and ‘f’ block elements and those of organometallic compounds are of immense importance because not only they furnish invaluable information regarding analysis and characterization of the compound thermodynamically but also give vital information regarding ‘specific enthalpy’ and ‘enthalpy density’. Thus viability and analysis of input and output of energy is of prime concern before any process or reaction or for that matter if any engine or industry is being set up because after all it is the process or reaction which takes place inside the engine. As the globe is gradually but certainly moving away from fossil fuel or carbon-based energy production as it immensely pollutes the environment due to evolution of greenhouse gases into the environment and contribute towards global warming, it is but necessary to evaluate the impact assessment of the pollutants on the environment before any engine or industry is being developed or installed. It is in this perspective that the thermochemical studies of metal compounds of ‘s’ ‘p’ ‘d’ and ‘f’ block elements and those of organometallic compounds become extremely important as it clearly identifies and defines the products as well as absorption and evolution of energy involved therein.

Annual inhalation dose of indoor radon in dwellings in Aizawl City, Mizoram, India

Radon gas is found in the environment, indoor and outdoor and its parent element being traced back to U238. Study of indoor radon inhalation dose have been carried out in Aizawl City, Mizoram, India in 24 dwellings, which were specifically selected according to the site location of the dwellings. Solid-state nuclear track detectors (SSNTD) have been used to obtain the time integrated concentration levels of indoor radon. DRPS (direct radon progeny sensor), which selectively register the tracks due to alpha emissions from 214Po from the deposited atoms of 222Rn progeny species is used for estimating the equilibrium equivalent radon concentration (EERC). The equilibrium factor (F-factor) for radon is then calculated using the measured EERC and concentrations of radon. The equilibrium factor may be defined as ratio of the amount of progeny nucleus to that of a parent nucleus. Inhalation dose has been obtained from the measured F-factor and concentrations of indoor radon. The data obtained in the present work has been analyzed to obtain the significant inhalation dose of indoor radon. From these observations it has been found that the annual inhalation dose of indoor radon in the study area is 624.89 mSv/y, which is low in comparison to the global average.

Effect of temperature on the infectivity of entomopathogenic nematodes (Steinernematidae and Heterorhaditidae) isolated from Mizoram, northeastern India

The study investigates the effect of temperature on the infectivity of two entomopathogenic nematodes, viz. Steinernema sp. and Heterorhabditis indica, locally isolated from Mizoram, northeastern India, using last instar larvae of greater wax moth, Galleria mellonella, as an insect host. Two hundred infective juveniles/larva of wax moth were exposed to different temperatures, viz. 10, 15, 20, 25, 30 and 35°C. It is observed that temperature play a significant role in infectivity of the two nematodes. No establishment of IJs were observed at 10°C, in addition 15°C in H. indica, and 35°C. Steinernema sp. appeared to be best adapted to temperatures between 15 and 30°C with an optimum temperature range of 25-30°C, whereas H. indica appeared to be adapted to temperatures between 20 and 30°C with an optimum temperature of 30°C.

The making of modern biotechnology: how ethidium bromide made fame

Ethidium bromide is a household name in biology, and is arguably the most popular stain in molecular research. It was discovered as a consequence of the growth spurt in chemical synthesis towards the very end of 19th century and in the first half of the 20th century. The precursor compound phenanthridine aroused its potential as a drug, basically because of its quinoline ring, which is interestingly the basis of the medicinal properties of important drugs, such as quinine, known at the time. A medical breakthrough was made in 1938 when some derivatives of phenanthridine were experimented to effectively kill Trypanosoma congolense and T. vivax, the protozoan parasites causing trypanosomiasis (sleeping sickness) in cattle. In 1946, the most effective compound was identified, and with slight chemical modification, it was mass produced as a trypanocidal drug, dimidium bromide, or trypadine. It was the principal veterinary drug in Africa until another chemical modification in 1952 yielded a more potent and less toxic compound, the now-famed ethidium bromide. Manufactured by Boots Pure Drug Co., Ltd. as homidium (Ethidium®), it served as the drug of choice in cattle trypanosomiasis for three decades. Its pharmacological property lies on its ability to intercalate between base pairs in the nucleic acids. It was a serendipitous moment when Piet Borst and Cees Aaij, dismayed at their broken ultracentrifuge, began to use the compound for staining DNA in gel electrophoresis. And the rest, as they say, is history.

Ethidium brouhaha: exorcising the EtBr demon from wimpy researchers

Ethidium bromide is a celebrity stain, and a very tainted one, in molecular biology. Its stigmatisation as a toxic, carcinogenic and mutagenic chemical has stirred an uncalled-for but what seems like a calculated hysteria among researchers. This has merely actuated what can be described as a necessary advertising war. The so-called safer alternatives are not overwhelmingly superior or entirely safe. For example, SYBR Green is, by evidence, more mutagenic. They may be regarded as optional, but at a higher financial cost. If anyone feels safer with extravagance, then the optional stains are an obvious choice. EtBr had been the principal drug for the mass treatment of cattle trypanosomiasis since the early 1950s, and no cancer has been reported among cattle. There are researchers who has handled the chemical throughout their career for decades, and none had made any complaint whatsoever. There is no medical record of molecular biologists taking cancer therapy because of EtBr. Milk producers are using it in large quantities. To the further extreme, people have actually drunk it without any apparent adverse effect. This is a lesson to learn that this is a case of bad meme and people have put an undue stain to this useful stain.

Factors affecting habitat selection by Mrs Hume’s Pheasant Syrmaticus humiae (Hume, 1881) in Mizoram, northeast India

Mrs Hume’s Pheasant Syrmaticus humiae (Hume, 1881) is a globally near-threatened pheasant species. It is sparsely distributed in eastern part of Mizoram, northeast India. The factors that influenced the habitat selection of S. humiae in the tropical montane forest are studied during January 2013 to March 2015. Based on preliminary survey a possible site of occurrence of the species was identified in the community reserved forest (CRF) adjacent to Lengteng Wildlife Sanctuary (LWS), near Myanmar border. Line transects were laid on two separate sites to determine the habitat use by the species. Physical variables were recorded on each transect sampling site. Only eight sightings are recorded at the Pine dominated area having good ground cover of tall grasses. The data analysis by principal component analysis (PCA) and stepwise logistic regressions analysis showed that litter cover and temperature plays a significant role (p<0.05) in the habitat selection by S. humiae. The possible reasons for this relationship are discussed and compared with other records.