Dynamics of telomere in ageing

Telomere are composed of G rich nucleotide (TTAGGG)n typically 20 kb in length, are the regions of repetitive DNA at the end of the chromosomes. As the eukaryotic cells divide, the protective ends of the linear chromosomes, the telomeres, gradually shorten with each cell division. When a critical telomere length is reached, the cells are signaled into senescence, an irreversible state of quiescence. Thus, telomere length has emerged as replicative clock within each population of cells. Since telomere are also non coding sequence of DNA, as that of introns, there might be specific sites as of 5’ splice site and 3’splice site, which might be the conserved regions in telomere and can possibility generate a signal for apoptosis after a certain time of cell division. Since Telomere Length (TL) in the somatic cells determines the number of cell divisions, TL has been proposed as a marker for biological ageing and cancer. Under conditions of chronic oxidative stress, the rate of telomere shortening is increased. Since telomeres consist of the repetitive sequence TTAGGG, and have a high GC content, they are very vulnerable to base oxidation. Additionally, DNA strand breaks are less efficiently repaired at the telomeres when compared to the rest of our genome. This means that reactive oxygen species cause more damage to the telomeres and this damage is less well repaired. Genetics play an important role in determining TL, but environmental and lifestyle factors such as smoking, alcohol consumption, physical activity, body composition and coffee and tea consumption can affect oxidative stress levels, which may contribute significantly to accelerated telomere shortening. Since, buccal cells are under direct contact with smoke and various toxic chemical substances in people who are acutely habituated with taking tobacco and cigarettes. So in our work we have found the conserved region of the telomere and showed the prolonged effect of tobacco and cigarettes on these conserved regions of the telomere

The Role of Charge Materials in Alternative Routes to Steel

New steelmaking technologies being developed presently are likely to have a significant impact on the future competitive structure of the steel industry. These technologies would not only lower costs but could greatly reduce the size requirement for efficient operations as well as eliminate several processing steps. Such technological developments always influence the structure of any industry. Development of oxygen steelmaking for example, offered lower scrap consumption compared to open hearth steelmaking, and this helped electric furnace steelmaking to grow by releasing scrap.Meanwhile, the developments of continuous billet casting allowed small steel electric furnace based plants to produce long products economically. The new technologies being developed today have the potential of causing even greater structural changes. Technologies such as smelting reduction, direct reduction, direct steelmaking from iron ore and near net shape casting are so revolutionary that they may change the complete rules of the game for steelmaking

Modelling of Rotary Kiln based Direct Reduction

Direct Reduction (DR) is the process by which iron ore, as oxide , is reduced by a reductant , viz., coal or natural gas to the product called sponge iron or Direct Reduced Iron( DRI). Coal based DR is carried out in a rotary kiln reactor where iron ore is reduced usually by noncoking coal . The kiln temperature is maintained at around 1000°C towards the discharge end, the rotati- onal speed is usually kept in the range of 0.4 to 0.7 r.p.m. While the inclination of the kiln is fixed in the range of 1.5° to 2.5°. The kiln rotational speed, coup- led with the inclination, imparts a forward motion to the charge bed of the kiln, thus aiding it to travel towards the discharge end. The charge consisting of iron ore and coal, while traversing the kiln length at high temperature, undergoes two simultaneous reactions, viz., gasification of the coal and reduction of the oxide ore. The oxide ore thus gradually gets converted to the lower oxides and finally, to the metallised poduct, DRI (90 - 95% metallised). However, the hot product from the kiln also contains coal char and ash and these being non-magnetic , are separated from the product DRI (magnetic) by magnetic separation . Before magnetic separation, the hot kiln-discharge product is cooled to about 100°C, usually in a rotary cooler , indirectly cooled by water

On Some Aspects of Basic Oxygen Steel Making with Prereduced Pellets

Under normal circumstances, a BOF can consume upto 30% of scrap in the charge which otherwise consists of molten pig iron. In steel plants where the basic oxygen process has been adopted, this requirement of scrap is generally met by scrap generated within the plant and by that bought from external sources. The composition of scrap, espec-ially that purchased from dealers, is notorious for its variation from wagon to wagon, batch to batch and even from season to season. This is particularly true of the sulphur content of the scrap which is a factor of funda-mental importance in BOF steelmaking, This inconsistency in scrap composition tends to give rise to undesirable variations both in the final bath composition and in the general bath behaviour during blowing. To keep these fluctuations under control, BOF operators have to constantly monitor the blow and adopt corrective measures when necessary. A stricter control over the materials charged into the BOF would therefore appear to be nece-ssary before automation is possible and the process is rendered less subject to variations. To this end, the substitution of scrap by prereduced pellets could prove worthwhile

Hawking radiation from dynamical horizons

In completely local settings, we establish that a dynamically evolving black hole horizon can be assigned a Hawking temperature. Moreover, we calculate the Hawking flux and show that the radius of the horizon shrinks.Comment: 5 Page