Elucidating the Response of Crop Plants towards Individual,Combined and Sequentially Occurring Abiotic Stresses

In nature, plants are exposed to an ever-changing environment with increasing frequencies of multiple abiotic stresses. These abiotic stresses act either in combination or sequentially, thereby driving vegetation dynamics and limiting plant growth and productivity worldwide. Plants’ responses against these combined and sequential stresses clearly differ from that triggered by an individual stress. Until now, experimental studies were mainly focused on plant responses to individual stress, but have overlooked the complex stress response generated in plants against combined or sequential abiotic stresses, as well as their interaction with each other. However, recent studies have demonstrated that the combined and sequential abiotic stresses overlap with respect to the central nodes of their interacting signaling pathways, and their impact cannot be modelled by swimming in an individual extreme event. Taken together, deciphering the regulatory networks operative between various abiotic stresses in agronomically important crops will contribute towards designing strategies for the development of plants with tolerance to multiple stress combinations. This review provides a brief overview of the recent developments in the interactive effects of combined and sequentially occurring stresses on crop plants. We believe that this study may improve our understanding of the molecular and physiological mechanisms in untangling the combined stress tolerance in plants, and may also provide a promising venue for agronomists, physiologists, as well as molecular biologists.     

CRISPR/Cas-Mediated Resistance against Viruses in Plants

CRISPR/Cas9 provides a robust and widely adaptable system with enormous potential for genome editing directed towards generating useful products. It has been used extensively to generate resistance against viruses infecting plants with more effective and prolonged efficiency as compared with previous antiviral approaches, thus holding promise to alleviate crop losses. In this review, we have discussed the reports of CRISPR/Cas-based virus resistance strategies against plant viruses. These strategies include approaches targeting single or multiple genes (or non-coding region) in the viral genome and targeting host factors essential for virus propagation. In addition, the utilization of base editing has been discussed to generate transgene-free plants resistant to viruses. This review also compares the efficiencies of these approaches. Finally, we discuss combinatorial approaches, including multiplexing, to increase editing efficiency and bypass the generation of escape mutants.     

New Antimicrobial Hexapeptides: Synthesis,Antimicrobial Activities,Cytotoxicity, and Mechanistic Studies

Synthetic antimicrobial peptides have recently emerged as promising candidates against drug‐resistant pathogens. We identified a novel hexapeptide, Orn‐D ‐Trp‐D ‐Phe‐Ile‐D ‐Phe‐His(1‐Bzl)‐NH₂, which exhibits broad‐spectrum antifungal and antibacterial activity. A lead optimization was undertaken by conducting a full amino acid scan with various proteinogenic and non‐proteinogenic amino acids depending on the hydrophobic or positive‐charge character of residues at various positions along the sequence. The hexapeptide was also cyclized to study the correlation between the linear and cyclic structures and their respective antimicrobial activities. The synthesized peptides were found to be active against the fungus Candida albicans and Gram‐positive bacteria such as methicillin‐resistant Staphylococcus aureus and methicillin‐resistant Staphylococcus epidermidis, as well as the Gram‐negative bacterium Escherichia coli; MIC values for the most potent structures were in the range of 1–5 μg mL^?1 (IC₅₀ values in the range of 0.02–2 μg mL^?1). Most of the synthesized peptides showed no cytotoxic effects in an MTT assay up to the highest test concentration of 200 μg mL^?1. A tryptophan fluorescence quenching study was performed in the presence of negatively charged and zwitterionic model membranes, mimicking bacterial and mammalian membranes, respectively. The results of the fluorescence study demonstrate that the tested peptides are selective toward bacterial over mammalian cells; this is associated with a preferential interaction between the peptides and the negatively charged phospholipids of bacterial cells.     

Plastic deformation-induced improved mechanical and thermal properties in hot-forged SiC-TiC composite

A novel SiC-20 vol% TiC composite prepared via a two-step sintering technique using 6.5 vol% Y₂O₃-Sc₂O₃-MgO exhibited high deformation (60 %) on hot forging attributed to the high-temperature plasticity of TiC (ductile to brittle transition temperature ～800 °C) and fine-grained microstructure (～276 nm). The newly developed SiC-TiC composite exhibited a ～2-fold increase in nominal strain as compared to that of monolithic SiC. The plastic deformation caused by grain-boundary sliding in monolithic SiC was supplemented by the plastic deformation of TiC in the SiC-TiC composite. The hot-forged composite exhibited anisotropy in its microstructure and mechanical and thermal properties due to the preferred alignment of α-SiC platelets formed in situ. The relative density, flexural strength, fracture toughness, and thermal conductivity of the composite increased from 98.4 %, 608 MPa, 5.1 MPa?m^1/2, and 34.6 Wm^?1 K^?1 in the as-sintered specimen to 99.9 %, 718–777 MPa, 6.9–7.8 MPa?m^1/2, and 54.8–74.7 Wm^?1 K^?1, respectively, on hot forging.     

Bonsai: diverse and shallow trees for extreme multi-label classification

Machine Learning - Extreme multi-label classification (XMC) refers to supervised multi-label learning involving hundreds of thousands or even millions of labels. In this paper, we develop a suite...     

An extended cell-average technique for a multi-dimensional population balance of granulation describing aggregation and breakage

This paper focuses on obtaining the numerical solution to a three-dimensional population balance model (PBM) of granulation using the cell-average technique first proposed by [22]. Conventionally, linear grids are used for the solution of PBMs, but the ability to incorporate non-linear grids would be more advantageous given that a larger size range can be covered using fewer number of grids, thus reducing computational overhead. Furthermore, the use of linear representation of grids in PBMs to represent industrial granulation processes that span a wide granule size range is computationally prohibitive and results show that a non-linear grid representation is computationally more efficient with comparable accuracy. Parallelization of the PBM via a multi-core strategy has also been incorporated in order to reduce the simulation time of the model. Incorporating the cell average technique along with parallelization of the overall model lends credence to the overall use of the model for effective granulation process design and analysis.     

Influence of CuO nanoparticles in enhancing the thermal conductivity of water and monoethylene glycol based nanofluids

In this paper the effect of CuO nanoparticles on the thermal conductivity of base fluids like mono ethylene glycol and water was studied. Both the base fluids showed enhancement in effective thermal conductivity. This enhancement was investigated with regard to various factors; concentration of nanoparticles, types of base fluids, sonication time and settlement time. For both the base fluids, an improvement in thermal conductivity was found as concentration of nanoparticles increased due to interaction between particles. It was also found that as the sonication time was increased, there was furthermore an improvement in the thermal conductivity of the base fluids. Effect of base fluids is the complex idea to understand. Lower base fluid's viscosities are supposed to contribute grater enchantment, but another factor of fluid nanoparticles surface interaction also more important. The experimentally measured thermal conductivities of base fluid's nanoparticles suspension were compared to a variety of models (Maxwell, Hamilton–Crosser and Bruggeman Model). It is observed that none of the mentioned models were found to predict accurately the thermal conductivities of nanofluids.     

Synthesis and characterization of nanocrystalline Zn1−xMxO (M = Ni, Cr) thin films for efficient photoelectrochemical splitting of water under UV irradiation

Nanocrystalline thin films of Zn_1−xM_xO (M = Ni, Cr) were deposited on glass substrate by sol-gel method. To a solution of zinc acetate 2-hydrate in dimethyl formamide, calculated quantities of nickel nitrate or chromium acetate were added. The clear solution, obtained after 2 h of continuous stirring, was coated on conducting glass (ITO plates). After preannealing at 250 °C to remove organic impurities, films were sintered at 400, 500 and 600 °C. XRD analysis reveals dominant evolution of hexagonal ZnO with a possible simultaneous growth of meta-stable cubic ZnO. AFM analysis indicated preferential growth of nanocrystallites along c-axis, while SEM analysis confirmed films having uniform morphology. Optical characterization led to two band gap values; one matching with the band gap of bulk ZnO and the second slightly higher, which suggest quantum confinement effect in nanocrystallites. Ni and Cr incorporation influenced the two band gap energies differently. Photoelectrochemical (PEC) splitting of water was attempted, using prepared thin films as working electrode, in conjunction with Pt counter electrode and saturated calomel reference electrode along with 150 W Xenon Arc light source and aqueous solution of NaOH (0.01 M). Results indicate Ni:ZnO films yielding improved photoresponse compared to Cr:ZnO films. Ni:ZnO (5 % at.) films sintered at 600 °C resulted in significantly enhanced photocurrent due to improved optical absorption and decrease in resistivity.