Particle composition and morphology over urban environment (New Delhi): Plausible effects on wheat leaves

Particulate matter (PM) deposition on leaves adversely affects physical, chemical and biological nature of agricultural crops resulting in their loss of productivity and yield. Wheat being a staple food in major parts of Northern India and around the World, has been selected for research purpose by designing a study to explore the probable effects of PM deposition on wheat leaves and wheat crops to ensure the food security. PM₅ (Particulate matter with aerodynamic diameter <5 μm) and Dry Deposited Particulate Matter (DDPM) on wheat leaves (Leaf_DDPM) were collected from the wheat crop field in Indian Agriculture Research Institute (IARI), New Delhi for growing and harvesting season of wheat crops (i.e. December 2014 to April 2015). The EDS (Energy Dispersive Spectroscopy) analysis was used for this study and the individual particle analysis revealed the presence of both acidic and alkaline components like C, Al, Si, Fe, Ca, K, S and Mg. The offline characterization tool i.e. SEM (Scanning Electron Microscope) was utilized for obtaining the micrographs which clearly showed the presence of some angular, sharp-edged and spherical particles consisting of both smooth and rough texture. Apart from that, prevalence of slightly non-spherical particles with aspect ratio of range (>1.20-1.40) and CIR (>0.70-0.80) for both PM₅ and leaf_DDPM were observed. The size distribution of individual particles for both PM₅(#194 particles) and Leaf_DDPM(#657 particles) revealed that Surface Equivalent Radius (SER) and Volume Equivalent Radius (VER) of particles observed to be 0.40-0.80 μm while surface area to be 0-1 μm². These particles may easily block stomatal openings (with typical diameter range: 42-51 μm) of wheat leaves and damage internal leaf tissues while particle VER determines the interaction of incoming solar radiation with leaf surfaces. Average PM₅ concentrations ± Standard deviations (μg/m³) were reported to be 231.05 ± 113.03. The XRF (X-Ray Fluorescence) spectrometer analysis of bulk PM₅ revealed the concentrations of non-carbonaceous elements (μg/m³) as N (67.34 ± 16.09), Si (27.44 ± 11.01), Al (7.79 ± 3.37), S (3.88 ± 2.24), Na (2.29 ± 0.94), Mg (1.65 ± 0.62), K (0.51 ± 0.26), Ca (0.60 ± 0.26), Fe (0.54 ± 0.26), Cr (1.10 ± 0.70), Zn (0.05 ± 0.03), P (0.10 ± 0.03), Cu (0.07 ± 0.06). The dominant elemental oxides were calculated as SiO₂, Al₂O₃, SO₄^2-, Na₂O, MgO, K₂O, CaO, Fe₂O₃, Cr₂O₃, ZnO, P₂O₅, Cu₂O with variable concentrations. In high humid conditions, with relative humidity (~85%) during the vegetative and flowering growth stages of wheat crops, presence of C and S rich acidic and hygroscopic particles may cause the corrosion of wheat leaves that ultimately affect the wheat crops.

Performance evaluation of light weight gas sensor system suitable for airborne applications against co-location gas analysers over Delhi

In the present work, we discuss the light-weight gas sensor system (LWGSS) [350 g, 7″ ∗ 3″] originally developed at CSIR-National Physical Laboratory. This instrument is equipped with low-cost electrolytic gas sensors for quantifying major gaseous pollutants present in the atmosphere. Alphasense electrochemical gas sensors were used to measure gas pollutant species such as CO, SO₂, NO₂, O₃ and H₂S. In our experiment, we focus on the observation of CO, SO₂, NO₂, O₃ using this system. LWGSS has been designed for vertical observations using balloons or unmanned aerial vehicles (UAVs) to study the gaseous concentration in the atmospheric boundary layer (ABL). But, before using such instruments in field campaigns, there is a strong need for the inter-comparison of these instruments with that of the collocated high-end gas analysers. Thus, the inter-comparisons were performed between LWGSS and other high-end analysers during 6-7, March 2017 and 26-27, April 2017. The LWGSS system comprising all the sensors was compared against high-end analyser present at CSIR-NPL for ozone and other gas analysers present at IMD, New Delhi. The ozone sensor deployed in LWGSS showed good correlation (i.e. R² = 0.83, slope = 0.93) against the high-end ozone gas analyser, which was calibrated with primary ozone facility (SRP43) available at CSIR-NPL. Inter-comparisons performed for NO₂, SO₂ and CO showed different results. While the NO₂ gas sensor showed medium correlation (R² = 0.75; slope = 0.49), the SO₂ and CO gas sensor showed a poor correlation (and R² = 0.44; slope = 0.98; R² = 0.28, slope = 0.79) respectively, when compared with co-location gas analysers present at IMD, New Delhi. Comparisons were performed for LWGSS data during 1-28 February 2018 with data collected at CPCB station (Shadipur, Delhi) and IMD station (Pusa, Delhi). The comparison results showed variations in LWGSS CO and SO₂ data whereas LWGSS O₃ and NO₂ results were in accordance with data collected at aforementioned monitoring stations.

Mechanisms involved in attenuated cardio-protective role of ischemic preconditioning in metabolic disorders

Myocardial infarction is a pathological state which occurs due to severe abrogation of the blood supply (ischemia) to a part of heart, which can cause myocardial damage. The short intermittent cycles of sub-lethal ischemia and reperfusion has shown to improve the tolerance of the myocardium against subsequent prolonged ischemia/reperfusion (I/R)-induced injury, which is known as ischemic preconditioning (IPC). Although, IPC-induced cardioprotection is well demonstrated in various species, including human beings, accumulated evidence clearly suggests critical abrogation of the beneficial effects of IPC in diabetes mellitus, hyperlipidemia and hyperhomocysteinemia. Various factors are involved in the attenuation of the cardioprotective effect of preconditioning, such as the reduced release of calcitonin gene-related peptide (CGRP), the over-expression of glycogen synthase kinase-3β (GSK-3β) and phosphatase and tensin homolog (PTEN), impairment of mito-KATP channels, the consequent opening of mitochondrial permeability transition pore (MPTP), etc. In this review, we have critically discussed the various signaling pathways involved in abrogated preconditioning in chronic diabetes mellitus, hyperlipidemia and hyperhomocysteinemia. We have also focused on the involvement of PTEN in abrogated preconditioning and the significance of PTEN inhibitors.

HIV-1 genome-encoded hiv1-mir-H1 impairs cellular responses to infection

The recent discovery of HIV-1 genome-encoded novel microRNA (miRNA; designated as hiv1-mir-H1) having ability to target selectively and specifically human cellular AATF gene, prompted us to explore the role of this miRNA in the regulation of genes involved in cellular apoptosis, proliferation and nucleic acid-based immune mechanism governed by miRNAs. Such a study revealed that this miRNA-induced knockdown of AATF gene, within normal human blood mononuclear cells, was responsible for the suppression of genes coding for Bcl-2, c-myc, Par-4 and Dicer. Further, hiv1-mir-H1 had the capacity to downregulate expression of cellular miR149 gene recognized to target Vpr gene encoded by HIV-1. Based upon these findings, we propose an "Epigenomic Pathway" through which hiv1-mir-H1 induced AATF gene knockdown within human mononuclear cells initiates their apoptosis.