Spatio-temporal variations of PM2.5 and Respiratory Deposition Dose (RDD) before and during different COVID-19 lockdown phases at Delhi, India

<p>Present study explores pre-lockdown (1<sup>st</sup> January-24<sup>th</sup> March, 2020) and during lockdown (25<sup>th</sup> March-20<sup>th</sup> June, 2020) air quality changes in PM<sub>2.5 </sub>along with meteorological effects at megacity- Delhi (28.7041°N, 77.1025°E). Alipur (Rural), Okhla (Industrial) and Pusa Road (Traffic dominant area) experienced mean concentrations (S.D.) of PM<sub>2.5 </sub>as 87.56(±54.06), 124.45(±73.49) and 62.14(±58.64) µg/m<sup>3 </sup>before lockdown(BL; 1<sup>st</sup> January-24<sup>th</sup> March, 2020), while for Lockdown1(L1; 25<sup>th</sup> March-14<sup>th</sup> April, 2020), PM<sub>2.5</sub> decreased drastically as 39.26(±16.31), 38.01(±15.16) and 31.03(±12.79) µg/m<sup>3</sup> and gradually increased during Lockdown2(L2; 15<sup>th</sup> April-3<sup>rd</sup> May, 2020), Lockdown3(L3; : 4<sup>th</sup> May-17<sup>th</sup> May, 2020), Lockdown4(L4; 18<sup>th</sup> May-31<sup>st</sup> May, 2020), respectively. Percentage decrease in PM<sub>2.5 </sub>(-69.46%) correlated with outdoor activities of percentage decrease (-70 to -80%) in L1, from BL phase. Exposure assessment study showed, mean Respiratory Deposition Dose-RDD (S.D.) (µg/hr) for fine particles [Particle diameter (Dp) =0.5 µm] for walk and sit mode during BL, as 27.22(±13.53) and 9.90(±4.91) for Alipur, 30.55(±18.04) and 11.11(±6.56) for Okhla, and 28.67(±14.39) and 10.43(±5.23) for Pusa road, and decreased during L1 as 9.64(±4.00) and 3.50(±1.46) for Alipur, 9.33(±3.72) and 3.39(±1.35) for Okhla, and 7.62(±3.14) and 2.77(±1.14) for Pusa road, respectively. Delhiites were exposed to more fine RDD(walk/sit) before lockdown than during lockdown phases. People in sit mode found less exposed to fine RDD, in comparison to walk condition. The people living indoors were affected by outdoor RDD exposure with windows open condition, while exposed to different indoor pollution sources with windows closed condition during lockdown. Authors suggest avoid use of closed conditioned indoors and ACs; frequent opening of windows to lower the RDD and to minimize the COVID-19 virus transmission via particulates.</p><p>Keywords: PM<sub>2.5</sub>, RDD, COVID-19.</p>

Possible medium and long range effects of depleted U-238 used in ammunition

In recent years a new type of ammunition has been included in the modern arsenals of Western countries. Depleted Uranium is used in the AlO's 30-mm gun and in a large variety of other projectiles used by Army, the Marines and Aviation. Due to the radioactive nature of this type of ammunition, it is important to know the distance of dispersion of the material produced. On account of its probable usage some hundred of km north from Greece we are interested in the evaluation of its impact on Greece. We assumed an amount of DU, equal to that daily released during the Gulf War, as being released in South Yugoslavia (Pristina). We examined the possibility of its transport to Greece at a distance more than 150 km far from the release point. For concentration, deposition, dose estimations and health effects evaluation COSYMA code is used. We assumed constant north winds of 5 m/s of speed, no rain, a mixing height equal to about 1000 m and D atmospheric stability conditions. Moreover taking account of the real wind situation during March and April 1999, we calculated the probable impact of daily releases, on selected days, to regions of Greece affected by air masses movement. The results indicate that in spite of the big amount considered as released in a single site, in no cases there has been found any appreciable radiological health effect.

Micro-patterning of Indium thin film for generation of micron and submicron particles using femtosecond laser-induced forward transfer

This paper reports on micro-pattering of Indium thin film (donor substrate) using a higher deposition dose than previously reported. The threshold deposition dose required for micro-patterning was measured. Ejected material from the micro-patterned thin film was deposited onto an accepter substrate kept in close proximity; it clearly shows deposition of micron and submicron particles of Indium. Moreover, a clean line like structure was deposited onto the accepter substrate when the accepter substrate was moved with the same velocity as that of the donor substrate.

Evaluation: Specific Energy Deposition from 252Cf-Sol-Gel Glass in Brain Interstitial Implants

Neutron brachytherapy show better results than conventional photon therapy for radioresistant tumors with hypoxic regions. Herein a comparative radiodosimetric analysis is presented considering 125I photon emitter seeds, often applied to brachytherapy, and a proposed Sol-Gel glass, synthesized with incorporated 252Cf neutron emitter, on a brain tumor implant. The proposition is to verify the viability of applying this bioceramic material. The methodology is based on the investigation of the specific energy deposition (dose) from 252Cf-Glass in deep brain interstitial implants through a stochastic computer code (MCNP5) and comparison with 125I seed’s energy deposition. 252Cf-Glass show dose per transition values higher than 125I seed’s set. RBE-isodose curves show a faster decrease of dose with the source distance increasing which can improve healthy tissue sparing.