Numerical simulations of different sectoral contributions to post monsoon pollution over Delhi.

The National Capital Region (NCR) of India, Delhi, has experienced high post-monsoon pollution along with several peak pollution episodes in recent years. Diwali, the festival of lights, which is among the biggest festivals of India celebrated during the post-monsoon season, is also considered a pollution event associated as it is with the lighting of a large number of firecrackers. 2016 Diwali pollution episode continued for a week creating severe discomfort to residents of Delhi, prompting the judiciary to ban the sale and use of firecrackers in Delhi from 2017 onwards. The current study analyzes different sectoral and temporal emissions contribution to the 2016 post monsoonal pollution episode over Delhi using a fully coupled chemical transport model. The findings of the study indicate that aerosols produced from crop residue open burning at the northwestern states contributed more than 60% of the total simulated surface concentration during the period under study. Model experimental simulations show that despite emissions from within the city, what explains the severity of pollution over Delhi during the period under consideration is an additional pollution load emanating from these intense crop open burning sessions from nearby areas. Further, model simulations show that while Diwali emissions can elevate the pollution load over Delhi, the effects do not last beyond 48 h. It is found that the stagnation of the pollutants several days beyond the 2016 Diwali day was due to favorable meteorological conditions like low surface temperature, lower boundary layer height, and weak northwesterly winds. The study shows that in order to improve air quality in Delhi during the post-monsoon period, mitigation efforts should target the adjacent rural areas, especially when there is massive burning of crop residue in those areas.

Melanin, a promising radioprotector: mechanisms of actions in a mice model.

The radioprotective effect of extracellular melanin, a naturally occurring pigment, isolated from the fungus Gliocephalotrichum simplex was examined in BALB/C mice, and the probable mechanism of action was established. At an effective dose of 50mg/kg body weight, melanin exhibited both prophylactic and mitigative activities, increasing the 30-day survival of mice by 100% and 60%, respectively, after exposure to radiation (7Gy, whole body irradiation (WBI)). The protective activity of melanin was primarily due to inhibition of radiation-induced hematopoietic damages as evidenced by improvement in spleen parameters such as index, total cellularity, endogenous colony forming units, and maintenance of circulatory white blood cells and platelet counts. Melanin also reversed the radiation-induced decrease in ERK phosphorylation in splenic tissue, which may be the key feature in its radioprotective action. Additionally, our results indicated that the sustained activation of AKT, JNK and P38 proteins in splenic tissue of melanin pre-treated group may also play a secondary role. This was also supported by the fact that melanin could prevent apoptosis in splenic tissue by decreasing BAX/Bcl-XL ratio, and increasing the expressions of the proliferation markers (PCNA and Cyclin D1), compared to the radiation control group. Melanin also reduced the oxidative stress in hepatic tissue and abrogated immune imbalance by reducing the production of pro-inflammatory cytokines (IL6 and TNFα). In conclusion, our results confirmed that fungal melanin is a very effective radioprotector against WBI and the probable mechanisms of radioprotection are due to modulation in pro-survival (ERK) signaling, prevention of oxidative stress and immunomodulation.

Note: compact helical pulse forming line for the generation of longer duration rectangular pulse.

The helical pulsed forming line (PFL) can generate longer duration rectangular pulse in a smaller length. A compact PFL using helical water line is designed and experimentally investigated. The impedance of the helical PFL is 22 [ohm sign]. The compactness is achieved in terms of reduction in length of the PFL by a factor of 5.5 using helical water PFL as compared to coaxial water PFL of same length. The helical PFL was pulsed charged to 200 kV using a high voltage pulse transformer in 4.5 µs and discharged into the matched 22 Ω resistive load through a self-breakdown pressurized spark gap switch. The rectangular voltage pulse of 100 kV, 260 ns (FWHM) is measured across the load. The effect of reduction in water temperature on the pulse width is also studied experimentally. The increase in pulse width up to 7% more is observed by reducing the temperature of the deionized water to 5 °C. It will further reduce the length of the PFL and make the system small for compact pulsed power drivers.

Low voltage operation of plasma focus.

Plasma foci of compact sizes and operating with low energies (from tens of joules to few hundred joules) have found application in recent years and have attracted plasma-physics scientists and engineers for research in this direction. We are presenting a low energy and miniature plasma focus which operates from a capacitor bank of 8.4 muF capacity, charged at 4.2-4.3 kV and delivering approximately 52 kA peak current at approximately 60 nH calculated circuit inductance. The total circuit inductance includes the plasma focus inductance. The reported plasma focus operates at the lowest voltage among all reported plasma foci so far. Moreover the cost of capacitor bank used for plasma focus is nearly 20 U.S. dollars making it very cheap. At low voltage operation of plasma focus, the initial breakdown mechanism becomes important for operation of plasma focus. The quartz glass tube is used as insulator and breakdown initiation is done on its surface. The total energy of the plasma focus is approximately 75 J. The plasma focus system is made compact and the switching of capacitor bank energy is done by manual operating switch. The focus is operated with hydrogen and deuterium filled at 1-2 mbar.

Foreign body in ENT--general practitioner's duty.

Foreign body in ENT region is an age-old problem. Introduction of foreign body in ear, nose and throat is specially seen in children. There are many types of foreign body seen in the ear, nose and throat. They can aspirate into larynx, trachea and bronchus. How to manage the removal of foreign body in ear, nose and throat had been discussed in a nutshell. General practitioners should be skilled enough to remove foreign body with their limited resources and they should know when to send the cases to an ENT specialist or to a hospital.

Effect of Phyllanthus niruri Linn. treatment on liver, kidney and testes in CCl4 induced hepatotoxic rats.

Phyllanthus niruri extract is extensively used in treating liver ailments. Effects of aqueous extract of P. niruri on liver, kidney and testes of CCl4 induced hepatotoxic rats were studied. High levels of malondialdehyde (MDA) were observed in the CCl4 test group with significant reduction of MDA levels in all groups on P. niruri extract administration. Highest levels of glutathione (GSH) were found in P. niruri group. Activities of alanine transaminase, aspartate transaminase and alkaline phosphatase enzymes were significantly reduced in the curative group (P. niruri treatment after CCl4 injection). Histopathology of liver showed lesser degree of inflammation in all P. niruri treated groups while the renal and seminiferous tubules showed eosinophilic protein casts with signs of tubular damage and degeneration. Testes also showed decreased amount of mature spermatozoa. The results suggest that P. niruri has anti-oxidant and hepato-protective activity with associated deleterious effects on kidney and testes.