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Effects of eccentricity and horizontal electric field (EH) on the binary‐collision outcomes of water drops are examined using numerically calculated collision characteristics from previous studies and results of simulation experiment conducted by the authors. For a fixed collision kinetic energy (CKE), filament breakups can occur at all values of eccentricity but events of coalescence decrease, and that of sheet breakup increase with increasing eccentricity in absence of EH. However, as EHincreases to ∼300 kVm−1it opposes the variability of the coalescence and sheet breakup events with eccentricity. When EHexceeds ∼300 kVm−1the collision outcomes might be determined only by the CKE and EH. The calculated value of coalescence efficiency and total number of fragments after a binary collision decreases with an increase in EH. It is argued that an electric field can significantly modify drop size distribution in thunderclouds and needs to be considered for development of precipitation. Growth of water drops in clouds is mostly governed by the drop size distribution in them. When two drops collide with each other, they can either coalesce to form a single larger drop, or disintegrate into many smaller drops, or bounce back. These different outcomes after their collisions are mostly determined by whether the collisions are centric where the eccentricity of the collision is zero or grazing where the eccentricity is one or somewhere in between the two extremes. The present study shows that if the collisions occur in presence of a horizontal electric field, it opposes the effect of eccentricity on the outcomes of the collisions. In this study, simultaneous effects of eccentricity and horizontal electric field are examined from numerically calculated collision characteristics from previous studies and utilizing the results of a simulation experiment recently conducted by the authors. Simultaneous effects of eccentricity and electric field on coalescence efficiency and total and spectral size distribution of fragments generated after the collision have also been evaluated. The results suggest that the electric field can significantly modify drop size distribution in thunderclouds and need to be considered for the development of precipitation. Horizontal electric field opposes the variability of coalescence/sheet breakup of water drops with eccentricity in binary collisionsNumber of fragments close to small (large) parent drop size decreases (increases) after collisions in the higher horizontal electric fieldBinary collisions in horizontal electric fields can substantially modify drop size distribution in thunderclouds Horizontal electric field opposes the variability of coalescence/sheet breakup of water drops with eccentricity in binary collisions Number of fragments close to small (large) parent drop size decreases (increases) after collisions in the higher horizontal electric field Binary collisions in horizontal electric fields can substantially modify drop size distribution in thunderclouds

ABSTRACTThe seasonal and inter annual variability of Tropospheric Nitrogen dioxide (NO2), Ozone (O3) and lightning activity over Maharashtra and adjoining part of states (15.5°N-22.5°N, 72.5°E-81.5°E) of India, is analyzed to study the role of lightning activity in the seasonal variation of NO2and O3. Satellite observations of Tropospheric NO2and O3from Aura- Ozone Monitoring Instrument (OMI)/Microwave Limb Sounder (MLS) for the period 2005–2016 and lightning data of 2014–2016 from lightning detection network over Maharashtra are used for analysis. Analyses show that the seasonal variations of all the three quantities are closely related to each other. The scatter plot between monthly NO2concentration verses monthly lightning activity for years 2014–2016 also show good correlation between these two parameters (r = 0.71, significant at 99.9%). Our analysis demonstrates that the seasonal and inter-annual variations in NO2and O3are affecting by lightning activity over study region. However, biomass burning during April-May and increased air pollution during winter months (November-January) also play important role in the intra seasonal variations of NO2and O3over this region.

Coalescence/breakup characteristics of binary collisions of small water drops (dS= 0.4–1.8 mm diameter) with large drops (dL= 3–3.5 mm diameter) occurring in the absence/presence of horizontal electric field (EH) = 0, 100, and 300 kVm−1have been investigated in a small vertical wind tunnel using a high‐speed digital camera. The coalescence efficiency (EC) of 0.299 observed for average diameters (dL= 3.2 mm, dS= 1.2 mm) in EH= 0 decreased to 0.244/0.211 when EHis increased to 100/300 kVm−1. The increase in the electric field reduces the probability of coalescence when Weber number (We) < 1. However, when We ≥ 1, an increase in We restricts the probability of coalescence. Our data, when plotted in the regime diagram in the We*‐pplane, delineates the collision outcomes in all‐electric field values but does show the overlapping of some data points in the adjacent categories. After a binary collision, the relaxation time for coalescence is higher than that for the breakup. Further, the relaxation time increases from the filament to sheet to disk mode of breakup in all‐electric field values. Fragment size distributions after the filament and sheet types of breakups differ and are differently affected by the applied electric field. Higher collision kinetic energy has a tendency to increase the number of fragments of the sizes between dLand dS. It is concluded therefore that, the effect of the electric field needs to be included in the estimation of drop growth and precipitation in clouds. Effect of horizontal electric field (EH) = 0, 100, and 300 kVm−1on the characteristics of binary collisions of small water drops (dS= 0.4–1.8 mm diameter) with large drops (dL= 3–3.5 mm diameter) has been investigated in a small vertical wind tunnel using a high‐speed digital camera. The coalescence efficiency (EC) of 0.299 observed for average diameters (dL= 3.2 mm, dS= 1.2 mm) in EH= 0 decreased to 0.244/0.211 when EHis increased to 100/300 kVm−1. The increase in the electric field reduces the probability of coalescence when a non‐dimensional parameter, Weber number (We) < 1. However, an increase in We restricts the probability of coalescence when We ≥ 1. After a binary collision, the relaxation time for coalescence is higher than that for the breakup and increases from the filament to sheet to disk mode of breakup in all‐electric field values. Fragment size distributions after the filament and sheet types of breakups differ. More violent collisions have a tendency to increase the number of fragments of the sizes between dLand dS. It is concluded therefore that, the effect of the electric field needs to be included in the estimation of drop growth and precipitation in clouds. Horizontal electric field decreases (increases) coalescence (breakup) efficiency of colliding water dropsThe drop growth occurs mainly through the smaller size drops having small collision kinetic energyRelaxation time is higher for the coalescence than for the breakup and it increases from the filament to sheet to disk in electric field Horizontal electric field decreases (increases) coalescence (breakup) efficiency of colliding water drops The drop growth occurs mainly through the smaller size drops having small collision kinetic energy Relaxation time is higher for the coalescence than for the breakup and it increases from the filament to sheet to disk in electric field

The ribosome-inhibiting toxin ricin binds exposed β1→4 linked galactosyls on multiple glycolipids and glycoproteins on the cell surface of most eukaryotic cells. After endocytosis, internal cell trafficking is promiscuous, with only a small proportion of ricin proceeding down a productive (cytotoxic) trafficking route to the endoplasmic reticulum (ER). Here, the catalytic ricin A chain traverses the membrane to inactivate the cytosolic ribosomes, which can be monitored by measuring reduction in protein biosynthetic capacity or cell viability. Although some markers have been discovered for the productive pathway, many molecular details are lacking. To identify a more comprehensive set of requirements for ricin intoxication, the authors have developed an RNAi screen in DrosophilaS2 cells, screening in parallel the effects of individual RNAi treatments alone and when combined with a ricin challenge. Initial screening of 806 gene knockdowns has revealed a number of candidates for both productive and nonproductive ricin trafficking, including proteins required for transport to the Golgi, plus potential toxin interactors within the ER and cytosol.