Publications by authors named "Mishra Shashank"

78 Publications

Single source precursor route to nanometric tin chalcogenides.

Dalton Trans 2021 Nov 30;50(46):17346-17360. Epub 2021 Nov 30.

Université Lyon 1, IRCELYON, CNRS-UMR 5256, 2 Avenue A. Einstein, 69626 Villeurbanne, France.

Low-temperature solution phase synthesis of nanomaterials using designed molecular precursors enjoys tremendous advantages over traditional high-temperature solid-state synthesis. These include atomic-level control over stoichiometry, homogeneous elemental dispersion and uniformly distributed nanoparticles. For exploiting these advantages, however, rationally designed molecular complexes having certain properties are usually required. We report here the synthesis and complete characterization of new molecular precursors containing direct Sn-E bonds (E = S or Se), which undergo facile decomposition under different conditions (solid/solution phase, thermal/microwave heating, single/mixed solvents, varying temperatures, .) to afford phase-pure or mixed-phase tin chalcogenide nanoflakes with defined ratios.
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http://dx.doi.org/10.1039/d1dt02964aDOI Listing
November 2021

Molecular Insights of 1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazole as CRF-1 Receptor Antagonists: Combined QSAR, Glide Docking, Molecular Dynamics, and ADME Studies.

Iran J Pharm Res 2021 ;20(2):22-34

Department of Pharmaceutical Chemistry, Bhupal Nobles' College of Pharmacy, Bhupal Nobles' University, Udaipur-313001, India.

Stress-dependent disorders cause severe harm to human health and trigger the risk of neurodegenerative disorder. Corticotropin-releasing factor-1 receptor was found to be a potent drug target.We evaluate the essential structural residues for pharmacophore identification through 2D and 3D QSAR analysis and identify the binding residues for a possible mechanism of CRF-1 binding with 1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazole derivatives through molecular docking and molecular dynamics simulations. The best 2D QSAR model was obtained through the MLR method with an r value of 0.8039 and a q value of 0.6311. Also,a 3D QSAR model was generated through the KNN MFA method with a q value of 0.6013 and a q_se value of 0.3167. Further, docking analysis revealed that residue Glu196 and Lys334 were involved in hydrogen bonding and Trp9 in Π- Π stacking. Simulation analysis proves that target protein interactions with ligands were stable, and changes were acceptable for small and globular proteins. Compound , a benzimidazole derivative, has an excellent binding affinity towards CRF-1 protein compared to reference molecules; hence, this compound could be a potential drug candidate for stress-dependent disorders. Based on findings, 1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazole derivatives could be a novel class of corticotropin-releasing factor 1 receptor antagonists for stress-related disorders. All benzimidazole derivatives were found to be within the acceptable range of physicochemical properties. Hence, these observations could provide valuable information for the design and development of novel and potent CRF-1 receptor antagonists.
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http://dx.doi.org/10.22037/ijpr.2020.113746.14464DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8457742PMC
January 2021

Vapor Phase Synthesis of SnS Facilitated by Ligand-Driven "Launch Vehicle" Effect in Tin Precursors.

Molecules 2021 Sep 3;26(17). Epub 2021 Sep 3.

Institute of Inorganic Chemistry, University of Cologne, Greinstraße 6, 50939 Cologne, Germany.

Extraordinary low-temperature vapor-phase synthesis of SnS thin films from single molecular precursors is attractive over conventional high-temperature solid-state methods. Molecular-level processing of functional materials is accompanied by several intrinsic advantages such as precise control over stoichiometry, phase selective synthesis, and uniform substrate coverage. We report here on the synthesis of a new heteroleptic molecular precursor containing (i) a thiolate ligand forming a direct Sn-S bond, and (ii) a chelating O^N^N-donor ligand introducing a "launch vehicle"-effect into the synthesized compound, thus remarkably increasing its volatility. The newly synthesized tin compound [Sn(SBu)()] was characterized by single-crystal X-ray diffraction analysis that verified the desired Sn:S ratio in the molecule, which was demonstrated in the direct conversion of the molecular complex into SnS thin films. The multi-nuclei (H, C, F, and Sn) and variable-temperature 1D and 2D NMR studies indicate retention of the overall solid-state structure of in the solution and suggest the presence of a dynamic conformational equilibrium. The fragmentation behavior of was analyzed by mass spectrometry and compared with those of homoleptic tin tertiary butyl thiolates [Sn(SBu)] and [Sn(SBu)]. The precursor was then used to deposit SnS thin films on different substrates (FTO, Mo-coated soda-lime glass) by CVD and film growth rates at different temperatures (300-450 °C) and times (15-60 min), film thickness, crystalline quality, and surface morphology were investigated.
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http://dx.doi.org/10.3390/molecules26175367DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8433875PMC
September 2021

Microbial methylglyoxal metabolism contributes towards growth promotion and stress tolerance in plants.

Environ Microbiol 2021 Aug 25. Epub 2021 Aug 25.

School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.

Plant growth promotion by microbes is a cumulative phenomenon involving multiple traits, many of which are not explored yet. Hence, to unravel microbial mechanisms underlying growth promotion, we have analysed the genomes of two potential growth-promoting microbes, viz., Pseudomonas sp. CK-NBRI-02 (P2) and Bacillus marisflavi CK-NBRI-03 (P3) for the presence of plant-beneficial traits. Besides known traits, we found that microbes differ in their ability to metabolize methylglyoxal (MG), a ubiquitous cytotoxin regarded as general consequence of stress in plants. P2 exhibited greater tolerance to MG and possessed better ability to sustain plant growth under dicarbonyl stress. However, under salinity, only P3 showed a dose-dependent induction in MG detoxification activity in accordance with concomitant increase in MG levels, contributing to enhanced salt tolerance. Furthermore, salt-stressed transcriptomes of both the strains showed differences with respect to MG, ion and osmolyte homeostasis, with P3 being more responsive to stress. Importantly, application of either strain altered MG levels and subsequently MG detoxification machinery in Arabidopsis, probably to strengthen plant defence response and growth. We therefore, suggest a crucial role of microbial MG resistance in plant growth promotion and that it should be considered as a beneficial trait while screening microbes for stress mitigation in plants.
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http://dx.doi.org/10.1111/1462-2920.15743DOI Listing
August 2021

Fallopian tube papilloma: An unusual cause of infertility.

Indian J Pathol Microbiol 2021 Jul-Sep;64(3):608-610

Department of Pathology and Molecular Medicine, Army Hospital (Research and Referral), Delhi Cantt, New Delhi, India.

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http://dx.doi.org/10.4103/IJPM.IJPM_240_20DOI Listing
November 2021

Influence of the choice of precursors on the synthesis of two-dimensional transition metal dichalcogenides.

Dalton Trans 2021 Sep 21;50(36):12365-12385. Epub 2021 Sep 21.

Institute of Inorganic Chemistry, University of Cologne, Greinstraße 6, D-50939 Cologne, Germany.

The interest in transition metal dichalcogenides (TMDCs; ME; M = transition metal; E = chalcogenide, y = valence of the metal) has grown exponentially across various science and engineering disciplines due to their unique structural chemistry manifested in a two-dimensional lattice that results in extraordinary electronic and transport properties desired for applications in sensors, energy storage and optoelectronic devices. Since the properties of TMDCs can be tailored by changing the stacking sequence of 2D monolayers with similar or dis-similar materials, a number of synthetic routes essentially based on the disintegration of bulk (, chemical exfoliation) or the integration of atomic constituents (, vapor phase growth) have been explored. Despite a large body of data available on the chemical synthesis of TMDCs, experimental strategies with high repeatability of control over film thickness, phase and compositional purity remain elusive, which calls for innovative synthetic concepts offering, for instance, self-limited growth in the -direction and homogeneous lateral topography. This review summarizes the recent conceptual advancements in the growth of layered van der Waals TMDCs from both mixtures of metal and chalcogen sources (multi-source precursors; MSPs) and from molecular compounds containing metals and chalcogens in one starting material (single-source precursor; SSPs). The critical evaluation of the strengths, limitations and opportunities of MSP and SSP approaches is provided as a guideline for the fabrication of TMDCs from commercial and customized molecular precursors. For example, alternative synthetic pathways using tailored molecular precursors circumvent the challenges of differential nucleation and crystal growth kinetics that are invariably associated with conventional gas phase chemical vapor transport (CVT) and chemical vapor deposition (CVD) of a mixture of components. The aspects of achieving high compositional purity and alternatives to minimize competing reactions or side products are discussed in the context of efficient chemical synthesis of TMDCs. Moreover, a critical analysis of the potential opportunities and existing bottlenecks in the synthesis of TMDCs and their intrinsic properties is provided.
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http://dx.doi.org/10.1039/d1dt01397aDOI Listing
September 2021

Coinage Metal Complexes with Di-tertiary-butyl Sulfide as Precursors with Ultra-Low Decomposition Temperature.

Chemistry 2021 Jul 24;27(42):10826-10832. Epub 2021 Jun 24.

Université Lyon 1, CNRS, UMR 5256, IRCELYON, Institut de recherches sur la catalyse et l'environnement de Lyon, 2 avenue Albert Einstein, 69626, Villeurbanne, France.

We report here the synthesis of [Cu (TFA) ( Bu S) ] (1), [Ag (TFA) ( Bu S) ] (2) and [AuCl( Bu S)] (3) (TFA=trifluoroacetate), which decompose in solution medium at ultra-low temperature (e. g., in boiling toluene) to afford phase-pure and highly crystalline Cu S , Ag S and metallic Au nanoparticles, respectively. The low decomposition temperature of these precursors is attributed to the facile decomposition mechanism in the di-tertiary-butyl sulfide ligand. These results are a significant step in the direction of establishing a general low-temperature strategy spanning a range of systems including thermodynamically metastable materials and incorporate them in technologies that are sensitive to the harsh conditions.
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http://dx.doi.org/10.1002/chem.202101471DOI Listing
July 2021

Proteomic approach to identify the differentially abundant proteins during flavour development in tuberous roots of Wight & Arn.

3 Biotech 2021 Apr 18;11(4):173. Epub 2021 Mar 18.

Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh India.

2-Hydroxy-4-Methoxy Benzaldehyde (2H4MB) is a structural isomer of vanillin produced in the tuberous roots of . Both vanillin and 2H4MB share the common phenylpropanoid pathway for their synthesis. Unlike vanillin, in which the biosynthetic pathway was well elucidated in , the 2H4MB biosynthetic pathway is not known in any of its plant sources. To find the key enzymes/proteins that promote 2H4MB biosynthesis, a comparative proteomic approach was adapted. In this case, two developmental stages of tuberous roots of were selected, where the flavour content was highly variable. The flavour content in the two stages was estimated using quantitative HPLC. The flavour content in the first and second stages of tuber development was 160 and 510 µgg, respectively. Two-dimensional electrophoresis (2-DE) was performed for these two stages of tubers; this was followed by PDquest analysis. A total of 180 protein spots were differentially abundant of which 57 spots were selected and subjected to MALDI-TOF-TOF analysis. The largest percentage of identified proteins was involved in stress and defence (27.9%), followed by proteins related to bioenergy and metabolism (23.2%), Cellular homeostasis proteins (18.6%), signaling proteins (11.6%), Plant growth and development proteins (9.3%). Holistically, we found the upregulation of methyltransferase, cell division responsive proteins, plant growth and development proteins which directly relate to flavour development and maturation. Similarly, stress-responsive and signaling proteins, vacuole proteins and ATPases were down-regulated with an increase in flavour content. In this study, we could not identify the specific 2H4MB metabolic pathway proteins, however, we could be able to study the changes in physiological and primary metabolic proteins with 2H4MB accumulation.

Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-021-02714-x.
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http://dx.doi.org/10.1007/s13205-021-02714-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7973354PMC
April 2021

Applying Machine Learning Technologies Based on Historical Activity Features for Multi-Resident Activity Recognition.

Sensors (Basel) 2021 Apr 4;21(7). Epub 2021 Apr 4.

Department of Electrical Engineering, National University of Tainan, Tainan 70005, Taiwan.

Due to the aging population, home care for the elderly has become very important. Currently, there are many studies focusing on the deployment of various sensors in the house to recognize the home activities of the elderly, especially for the elderly living alone. Through these, we can detect the home situation of the single person and ensure his/her living safety. However, the living environment of the elderly includes, not only the person living alone, but also multiple people living together. By applying the traditional methods for a multi-resident environment, the "individual" activities of each person could not be accurately identified. This resulted in an inability to distinguish which person was involved in what activities, and thus, failed to provide personal care. Therefore, this research tries to investigate how to recognize home activities in multi-resident living environments, in order to accurately distinguish the association between residents and home activities. Specifically, we propose to use the special characteristics of historical activity of residents in a multi-person environment, including activity interaction, activity frequency, activity period length, and residential behaviors, and then apply a suite of machine learning methods to train and test. Five traditional models of supervised learning and two deep learning methods are explored to tackle this problem. Through the experiments with real datasets, the proposed methods were found to achieve higher precision, recall and accuracy with less training time. The best accuracy can reach up to 91% and 95%, by J48DT, and LSTM, respectively, in different living environments.
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http://dx.doi.org/10.3390/s21072520DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8038457PMC
April 2021

Computational property predictions of Ta-Nb-Hf-Zr high-entropy alloys.

Sci Rep 2021 Mar 1;11(1):4815. Epub 2021 Mar 1.

TCS Research, Tata Research Development and Design Center, 54-B Hadapsar Industrial Estate, Hadapsar, Pune, Maharashtra, 411013, India.

Refractory high entropy alloys (R-HEAs) are becoming prominent in recent years because of their properties and uses as high strength and high hardness materials for ambient and high temperature, aerospace and nuclear radiation tolerance applications, orthopedic applications etc. The mechanical properties like yield strength and ductility of TaNbHfZr R-HEA depend on the local nanostructure and chemical ordering, which in term depend on the annealing treatment. In this study we have computationally obtained various properties of the equimolar TaNbHfZr alloy like the role of configurational entropy in the thermodynamic property, rate of evolution of nanostructure morphology in thermally annealed systems, dislocation simulation based quantitative prediction of yield strength, nature of dislocation movement through short range clustering (SRC) and qualitative prediction of ductile to brittle transition behavior. The simulation starts with hybrid Monte Carlo/Molecular Dynamics (MC/MD) based nanostructure evolution of an initial random solid solution alloy structure with BCC lattice structure created with principal axes along [1 1 1], [- 1 1 0] and [- 1 - 1 2] directions suitable for simulation of ½[1 1 1] edge dislocations. Thermodynamic properties are calculated from the change in enthalpy and configurational entropy, which in term is calculated by next-neighbor bond counting statistics. The MC/MD evolved structures mimic the annealing treatment at 1800 °C and the output structures are replicated in periodic directions to make larger 384,000 atom structures used for dislocation simulations. Edge dislocations were utilized to obtain and explain for the critically resolved shear stress (CRSS) for the structures with various degrees of nanostructure evolution by annealing, where extra strengthening was observed because of the formations of SRCs. Lastly the MC/MD evolved structures containing dislocations are subjected to a high shear stress beyond CRSS to investigate the stability of the dislocations and the lattice structures to explain the experimentally observed transition from ductile to brittle behavior for the TaNbHfZr R-HEA.
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http://dx.doi.org/10.1038/s41598-021-84260-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7921137PMC
March 2021

Designed sol-gel precursors for atomically dispersed Nb and Pb within TiO as catalysts for dihydroxyacetone transformation.

Dalton Trans 2021 Feb;50(5):1604-1609

Université Claude Bernard Lyon 1, CNRS, UMR 5256, Institut de Recherches sur la Catalyse et l'Environnement de Lyon (IRCELYON), 2 avenue Albert Einstein, 69626 Villeurbanne, France.

The 'bottom-up' synthesis of homogeneously doped metal oxide nanoparticles (NPs) with precision at the atomic/molecular level offers many advantages. We report here the synthesis, structural characterization and hydrolytic behavior of new N-methyldiethanolamine-modified precursors of Ti(iv), Nb(v) and Pb(ii) and their application as excellent sol-gel precursors for obtaining atomically dispersed Nb and Pb within TiO2 having high surface areas (253-355 m2 g-1) and tunable acidic properties. Preliminary results on the use of these doped TiO2 as water-tolerant catalysts in transforming dihydroxyacetone to lactic acid are presented.
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http://dx.doi.org/10.1039/d0dt03726eDOI Listing
February 2021

Pituicytoma: Case report of a rare suprasellar tumor.

Indian J Pathol Microbiol 2021 Jan-Mar;64(1):145-148

Department of Pathology and Molecular Medicine, Army Hospital Research and Referral, Delhi Cantt, New Delhi, India.

Pituicytoma is a distinct sellar or supracellar tumor which originates from specialized glial cells of neurohypophyses and infundibulum known as pituicytes. Because of its sellar location patients present with headache, visual disturbance, and endocrine abnormalities. Pituicytoma is difficult to diagnose on neuroimaging as radiological features overlap with other more common tumors of this region. Thus, diagnosis is established by histopathology and immunohistochemistry of resected tumor only. Pituicytomas are composed of bipolar spindle cells arranged as fascicles and are immunoreactive for TTF-1, S100p, and vimentin. These tumors are extremely rare and only around 70 published cases are known in literature. We report a case of suprasellar SOL in a 58-year-old male who presented with headache and gradual visual deterioration in both eyes. He was diagnosed as a case of pituicytoma based on light microscopy findings and immunohistochemical expression of TTF-1, vimentin, S100p, and bcl-2.
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http://dx.doi.org/10.4103/IJPM.IJPM_430_20DOI Listing
July 2021

Root system architecture, physiological analysis and dynamic transcriptomics unravel the drought-responsive traits in rice genotypes.

Ecotoxicol Environ Saf 2021 Jan 8;207:111252. Epub 2020 Sep 8.

CSIR-National Botanical Research Institute, Lucknow, 226001, India. Electronic address:

Drought is the major abiotic factors that limit crop productivity worldwide. To withstand stress conditions, plants alter numerous mechanisms for adaption and tolerance. Therefore, in the present study, 106 rice varieties were screened for drought tolerance phenotype via exposing different concentrations of polyethylene glycol 6000 (PEG) in the hydroponic nutrient medium at the time interval of 1, 3, and 7 days to evaluate the changes in their root system architecture. Further, based on root phenotype obtained after PEG-induced drought, two contrasting varieties drought-tolerant Heena and -sensitive Kiran were selected to study transcriptional and physiological alterations at the same stress durations. Physiological parameters (photosynthesis rate, stomatal conductance, transpiration), and non-enzymatic antioxidants (carotenoids, anthocyanins, total phenol content) production indicated better performance of Heena than Kiran. Comparatively higher accumulation of carotenoid and anthocyanin content and the increased photosynthetic rate was also observed in Heena. Root morphology (length, numbers of root hairs, seminal roots and adventitious roots) and anatomical data (lignin deposition, xylem area) enable tolerant variety Heena to better maintain membrane integrity and relative water content, which also contribute to comparatively higher biomass accumulation in Heena under drought. In transcriptome profiling, significant drought stress-associated differentially expressed genes (DEGs) were identified in both the varieties. A total of 1033 and 936 uniquely upregulated DEGs were found in Heena and Kiran respectively. The significant modulation of DEGs that were mainly associated with phytohormone signaling, stress-responsive genes (LEA, DREB), transcription factors (TFs) (AP2/ERF, MYB, WRKY, bHLH), and genes involved in photosynthesis and antioxidative mechanisms indicate better adaptive nature of Heena in stress tolerance. Additionally, the QTL-mapping analysis showed a very high number of DEGs associated with drought stress at AQHP069 QTL in Heena in comparison to Kiran which further distinguishes the drought-responsive traits at the chromosomal level in both the contrasting varieties. Overall, results support the higher capability of Heena over Kiran variety to induce numerous genes along with the development of better root architecture to endure drought stress.
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http://dx.doi.org/10.1016/j.ecoenv.2020.111252DOI Listing
January 2021

Computational investigation of potential inhibitors of novel coronavirus 2019 through structure-based virtual screening, molecular dynamics and density functional theory studies.

J Biomol Struct Dyn 2021 Aug 15;39(12):4449-4461. Epub 2020 Jul 15.

Department of Pharmaceutical Chemistry, Bhupal Nobles' College of Pharmacy, Bhupal Nobles' University, Udaipur, India.

Despite the intensive research efforts towards antiviral drug against COVID-19, no potential drug or vaccines has not yet discovered. Initially, the binding site of COVID-19 main protease was predicted which located between regions 2 and 3. Structure-based virtual screening was performed through a hierarchal mode of elimination technique after generating a grid box. This led to the identification of five top hit molecules that were selected on the basis of docking score and visualization of non-bonding interactions. The docking results revealed that the hydrogen bonding and hydrophobic interactions are the major contributing factors in the stabilization of complexes. The docking scores were found between -7.524 and -6.711 kcal/mol indicating strong ligand-protein interactions. Amino acid residues Phe140, Leu141, Gly143, Asn142, Thr26, Glu166 and Thr190 (hydrogen bonding interactions) and Phe140, Cys145, Cys44, Met49, Leu167, Pro168, Met165, Val42, Leu27 and Ala191 (hydrophobic interactions) formed the binding pocket of COVID-19 main protease. From identified hits, ZINC13144609 and ZINC01581128 were selected for atomistic MD simulation and density functional theory calculations. MD simulation results confirm that the protein interacting with both hit molecules is stabilized in the chosen POPC lipid bilayer membrane. The presence of lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) in the hydrophobic region of the hit molecules leads to favorable ligand-protein contacts. The calculated pharmacokinetic descriptors were found to be in their acceptable range and therefore confirming their drug-like properties. Hence, the present investigation can serve as the basis for designing and developing COVID-19 inhibitors. Communicated by Ramaswamy H. Sarma.
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http://dx.doi.org/10.1080/07391102.2020.1791957DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7441804PMC
August 2021

Optimum in the thermoelectric efficiency of nanostructured Nb-doped TiO ceramics: from polarons to Nb-Nb dimers.

Phys Chem Chem Phys 2020 Jun;22(23):13008-13016

IRCELYON, Université Lyon1 - CNRS, UMR 5256, 2 Avenue Albert Einstein, 69626 Villeurbanne, France.

Rutile is the most common and stable polymorph form of titanium oxide TiO2 at all temperatures. The doping of rutile TiO2 with a small amount of niobium is reknown for being responsible for a large increase of the electrical conductivity by several orders of magnitude, broadening its technological interest towards new emerging fields such as the thermoelectric conversion of waste heat. The electronic conduction has been found to be of a polaronic nature with strongly localized charges around the Ti3+ centers while, on the other side, the relatively high value of the thermal conductivity implies the existence of lattice heat carriers, i.e. phonons, with large mean free paths which makes the nanostructuration relevant for optimizing the thermoelectric efficiency. Here, the use of a high-pressure and high-temperature sintering technique has allowed to vary the grain size in rutile TiO2 pellets from 300 to 170 nm, leading to a significant reduction of the lattice thermal conductivity. The thermoelectric properties (electrical conductivity, Seebeck coefficient and thermal conductivity) of Nb-doped rutile nanostructured ceramics, namely NbxTi1-xO2 with x varying from 1 to 5%, are reported from room temperature to ∼900 K. With the incorporation of Nb, an optimum in the thermoelectric properties together with an anomaly on the tetragonal lattice constant c are observed for a concentration of ∼2.85%, which might be the fingerprint of the formation of short Nb dimers.
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http://dx.doi.org/10.1039/d0cp00652aDOI Listing
June 2020

Molecular Engineering of Metal Alkoxides for Solution Phase Synthesis of High-Tech Metal Oxide Nanomaterials.

Chemistry 2020 Jul 2;26(42):9292-9303. Epub 2020 Jul 2.

C2P2-UMR 5265, ESCPE-Lyon, BP 2077, Univ Lyon, Université Claude Bernard Lyon 1, 69616, Villeurbanne, France.

The 'bottom-up' synthesis of inorganic nanomaterials with precision at the atomic/molecular level offers many opportunities for the design and improvement of the nanomaterials for various applications. Molecular engineering during soft chemical processing for the synthesis of functional nanomaterials enables the desired chemical and physical properties of the precursors, such as solubility or volatility, clean decomposition, control of stoichiometry for multimetallic species to name a few, and leads to easy control of uniform particle size distribution, stoichiometry…. This Minireview illustrates some important aspects of the molecular engineering in light of some recent developments from the molecular synthesis of nanomaterials involving non-silicon metal alkoxide systems for high-tech applications.
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http://dx.doi.org/10.1002/chem.202000534DOI Listing
July 2020

Molecules versus Nanoparticles: Identifying a Reactive Molecular Intermediate in the Synthesis of Ternary Coinage Metal Chalcogenides.

Inorg Chem 2020 Jun 15;59(11):7727-7738. Epub 2020 May 15.

Institut de Recherches sur la Catalyse et l'Environnement de Lyon (IRCELYON), Université Lyon, Université Claude Bernard Lyon 1, CNRS, UMR 5256, 2 avenue Albert Einstein, 69626 Villeurbanne, France.

The identification of reactive intermediates during molecule-to-nanoparticle (NP) transformation has great significance in comprehending the mechanism of NP formation and, therefore, optimizing the synthetic conditions and properties of the formed products. We report here the room temperature (RT) synthesis of AgCuSe NPs from the reaction of di--butyl selenide with trifluoroacetates (TFA) of silver(I) and copper(II). The isolation and characterization of a molecular species during the course of this reaction, [AgCu(TFA)(BuSe)] (), which shows extraordinary reactivity and interesting thermochromic behavior (blue at 0 °C and green at RT), confirmed that ternary metal selenide NPs are formed via this intermediate species. Similar reactions with related dialkyl chalcogenide RE resulted in the isolation of molecular species of similar composition, [AgCu(TFA)(RE)] [R = Bu, E = S (); R = Me, E = Se (); R = Me, E = S ()], which are stable at RT but can be converted to ternary metal chalcogenides at elevated temperature. Density functional theory calculations confirm the kinetic instability of and throw light on its thermochromic properties.
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http://dx.doi.org/10.1021/acs.inorgchem.0c00758DOI Listing
June 2020

Omics-Based Mechanistic Insight Into the Role of Bioengineered Nanoparticles for Biotic Stress Amelioration by Modulating Plant Metabolic Pathways.

Front Bioeng Biotechnol 2020 17;8:242. Epub 2020 Apr 17.

CSIR-National Botanical Research Institute, Lucknow, India.

Bioengineered silver nanoparticles can emerge as a facile approach to combat plant pathogen, reducing the use of pesticides in an eco-friendly manner. The plants' response during tripartite interaction of plant, pathogen, and nanoparticles remains largely unknown. This study demonstrated the use of bioengineered silver nanoparticles in combating black spot disease caused by necrotrophic fungus in via foliar spray. The particles reduced disease severity by 70-80% at 5 μg/ml without showing phytotoxicity. It elicited plant immunity by a significant reduction in reactive oxygen species (ROS), decreases in stress enzymes by 0.6-19.8-fold, and emergence of autophagy. Comparative plant proteomics revealed 599 proteins expressed during the interaction, where 117 differential proteins were identified. Among different categories, proteins involved in bioenergy and metabolism were most abundant (44%), followed by proteins involved in plant defense (20%). Metabolic profiling by gas chromatography-mass spectroscopy yielded 39 metabolite derivatives in non-polar fraction and 25 in the polar fraction of plant extracts. It was observed that proteins involved in protein biogenesis and early plant defense were overexpressed to produce abundant antimicrobial metabolites and minimize ROS production. Bioengineered silver nanoparticles performed dual functions to combat pathogen attack by killing plant pathogen and eliciting immunity by altering plant defense proteome and metabolome.
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http://dx.doi.org/10.3389/fbioe.2020.00242DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7180193PMC
April 2020

Heteroleptic Tin(IV) Aminoalkoxides and Aminofluoroalkoxides as MOCVD Precursors for Undoped and F-Doped SnO Thin Films.

Inorg Chem 2020 May 27;59(10):7167-7180. Epub 2020 Apr 27.

Université Claude Bernard Lyon 1, C2P2, CPE Lyon - CNRS, UMR 5265, 43 Bvd du 11 Novembre 1918, 69616 Villeurbanne, France.

A series of asymmetric and potentially bidentate amino alcohols and amino fluoro alcohols (ROH) having a different number of methyl/trifluoromethyl substituents at the α-carbon atom, [HOC(R)(R)CHNMe] (R = R = H (dmaeH); R = H, R = CH (dmapH); R = R = CH (dmampH); R = H, R = CF (F-dmapH); R = R = CF (F-dmampH)) have been used to develop new monomeric and heteroleptic tin(IV) amino(fluoro)alkoxides [Sn(OR)(OR)] (R = Et, Pr, Bu). These new complexes, which were thoroughly characterized by spectroscopy (IR and multinuclei NMR (H, C, F, and Sn)) as well as single-crystal X-ray studies on representative samples, were investigated for their thermal behavior to determine their suitability as MOCVD precursors for the deposition of metal oxide thin films. The two most suitable compounds, [Sn(OBu)(dmamp)] and [Sn(OBu)(F-dmamp)], were used in a direct liquid injection chemical vapor deposition (DLI-CVD) process to deposit undoped SnO and F-doped SnO thin films, respectively, on silicon and quartz substrates. Film growth rates at different temperatures (from 400 to 700 °C), film thickness, crystalline quality, and surface morphology were investigated. The films deposited on quartz showed high transparency (above 80%) in the visible region and low carbon contamination on the surface (11-13% from XPS), which could easily be removed completely with 2 min of Ar sputtering.
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http://dx.doi.org/10.1021/acs.inorgchem.0c00617DOI Listing
May 2020

Synthesis of 2-methoxy-3-(thiophen-2-ylmethyl)quinoline containing amino carbinols as antitubercular agents.

Bioorg Chem 2020 06 21;99:103775. Epub 2020 Mar 21.

Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute BS, 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India; Academiy of Scientific and Innovative Research, New Delhi 110001, India. Electronic address:

We have designed and synthesized 2-methoxy-3-(thiophen-2-ylmethyl)quinoline containing amino carbinols as possible anti-tubercular agents to combat the disease. These molecules were synthesized by tethering amino ether linkage with hydroxyl group to diarylquinoline skeleton; hydroxyl and amine chains were engrafted on diaryl ring. They were evaluated against strain (HR) of Mycobacterium tuberculosis and most of compounds showed in vitro antitubercular activity. Two compounds having diaryl quinoline hydroxyl amino ether scaffold and three compounds having diaryl amino alkyl carbinol core showed activities at 6.25 μg/mL. This study explores diaryl carbinol prototype as inhibitor against Mycobacterium tuberculosis.
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http://dx.doi.org/10.1016/j.bioorg.2020.103775DOI Listing
June 2020

Revealing the complexity of protein abundance in chickpea root under drought-stress using a comparative proteomics approach.

Plant Physiol Biochem 2020 Jun 6;151:88-102. Epub 2020 Mar 6.

Microbial Technology Division, Council of Scientific and Industrial Research-National Botanical Research Institute (CSIR-NBRI), Rana Pratap Marg, Lucknow, 226001, India. Electronic address:

Global warming has reached an alarming situation, which led to a dangerous climatic condition. The irregular rainfalls and land degradation are the significant consequences of these climatic changes causing a decrease in crop productivity. The effect of drought and its tolerance mechanism, a comparative roots proteomic analysis of chickpea seedlings grown under hydroponic conditions for three weeks, performed at different time points using 2-Dimensional gel electrophoresis (2-DE). After PD-Quest analysis, 110 differentially expressed spots subjected to MALDI-TOF/TOF and 75 spots identified with a significant score. These identified proteins classified into eight categories based on their functional annotation. Proteins involved in carbon and energy metabolism comprised 23% of total identified proteins include mainly glyceraldehyde-3-phosphate dehydrogenase, malate dehydrogenase, transaldolase, and isocitrate dehydrogenase. Proteins related to stress response (heat-shock protein, CS domain protein, and chitinase 2-like) contributed 16% of total protein spots followed by 13% involved in protein metabolism (adenosine kinase 2, and protein disulfide isomerase). ROS metabolism contributed 13% (glutathione S-transferase, ascorbate peroxidase, and thioredoxin), and 9% for signal transduction (actin-101, and 14-3-3-like protein B). Five percent protein identified for secondary metabolism (cinnamoyl-CoA reductase-1 and chalcone-flavononeisomerase 2) and 7% for nitrogen (N) and amino acid metabolism (glutamine synthetase and homocysteine methyltransferase). The abundance of some proteins validated by using Western blotting and Real-Time-PCR. The detailed information for drought-responsive root protein(s) through comparative proteomics analysis can be utilized in the future for genetic improvement programs to develop drought-tolerant chickpea lines.
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http://dx.doi.org/10.1016/j.plaphy.2020.03.005DOI Listing
June 2020

Characterization of plant growth-promoting alkalotolerant Alcaligenes and Bacillus strains for mitigating the alkaline stress in Zea mays.

Antonie Van Leeuwenhoek 2020 Jul 9;113(7):889-905. Epub 2020 Mar 9.

CSIR- National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226 001, India.

Intensification of sodic soil due to increasing pH is an emerging environmental issue. The present study aimed to isolate and characterise alkaline stress-tolerant and plant growth-promoting bacterial strains from moderately alkaline soil (pH 8-9), strongly alkaline soil (pH 9-10), and very strongly alkaline soil (> 10). Total 68 bacteria were isolated, and screened for multiple plant growth promoting (PGP) attributes. Out of total, 42 isolates demonstrating at least three plant growth promoting PGP traits selected for further assays. Then out of 42, 15 bacterial isolates were selected based on enhanced maize plant growth under greenhouse experiment, and 16S rRNA gene sequencing revealed Bacillus spp. as a dominant genus. Furthermore, based on improved seed germination percentage and biomass of maize (Zea mays L.) under alkaline stress conditions Alcaligenes sp. NBRI NB2.5, Bacillus sp. NBRI YE1.3, and Bacillus sp. NBRI YN4.4 bacterial strains were selected, and evaluated for growth-promotion and alkaline stress amelioration under greenhouse condition. Amongst the selected 3 plant growth promoting rhizobacterial (PGPR) strains, Bacillus sp. NBRI YN4.4 significantly improved the photosynthetic pigments and soluble sugar content, and decreased proline level in inoculated maize plants as compared to uninoculated control under stress conditions. Moreover, significantly enhanced soil enzymes such as dehydrogenase, alkaline phosphatase and betaglucosidase due to inoculation of Bacillus sp. NBRI YN4.4 in maize plants grown in alkaline soil attributes to its role in improving the soil health. Therefore, alkaline stress-tolerant PGPR NBRI YN4.4 can be useful for developing strategies for the reclamation of saline/sodic soils and improving the plant growth and soil health in sustainable manner.
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http://dx.doi.org/10.1007/s10482-020-01399-1DOI Listing
July 2020

Room-temperature conversion of CuSe to CuAgSe nanoparticles to enhance the photocatalytic performance of their composites with TiO.

Dalton Trans 2020 Mar;49(11):3580-3591

Université Claude Bernard Lyon 1, CNRS, UMR 5256, Institut de Recherches sur la Catalyse et l'Environnement de Lyon (IRCELYON), 2 Avenue Albert Einstein, 69626 Villeurbanne, France.

Rational design and precise engineering are needed to optimize the structural and chemical parameters of functional materials. In this work, we demonstrate how pre-formed binary metal selenides can be an excellent synthetic choice for the synthesis of ternary coinage metal selenide nanoparticles (NPs) with controlled composition. The mild conditions required to obtain these ternary coinage metal selenide NPs offered an easy synthesis of n% CuAgSe-TiO2 (n = 0.01, 0.1, 0.3 and 1.0 mol%) nanocomposites for photocatalytic applications without compromising the structural and morphological characteristics of TiO2 and without having any organic ligands around the NPs. The use of ternary metal selenide nanocomposites CuAgSe-TiO2 results in a clear improvement in their photocatalytic activity for the photodegradation of formic acid as compared to the well-known benchmark for photocatalysis, TiO2 (P25), and its binary metal selenide nanocomposites Cu2-xSe-TiO2. DFT calculations establish semi-metallic behavior of CuAgSe NPs and show that CuAgSe-TiO2 forms a semimetallic-semiconductor heterojunction allowing a better charge separation to enhance its photocatalytic activity.
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http://dx.doi.org/10.1039/c9dt04726cDOI Listing
March 2020

Drought tolerant Ochrobactrum sp. inoculation performs multiple roles in maintaining the homeostasis in Zea mays L. subjected to deficit water stress.

Plant Physiol Biochem 2020 May 19;150:1-14. Epub 2020 Feb 19.

Microbial Technologies Division, Council of Scientific and Industrial Research-National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India. Electronic address:

Plant growth-promoting rhizobacteria (PGPR) improve plant health under various biotic and abiotic stresses. However, the underlying mechanisms of the protective effects of PGPR in deficit water stress (WS) remain less explored. This study aimed to characterize the role of Ochrobactrum sp. NBRISH6 inoculation on maize (Zea mays "Maharaja") under WS conditions using multiple approaches such as physiological, anatomical, metabolic, and molecular. The effect of NBRISH6 inoculation using maize as a host plant was characterized under greenhouse conditions in deficit water stress. Results from this study demonstrated that NBRISH6 significantly lowered the expression of genes involved in the abscisic acid cycle, deficit water stress-response, osmotic stress, and antioxidant enzyme activity (superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase, and polyphenol oxidase). Phytohormones, i.e. indole acetic acid (IAA) and salicylic acid (SA) levels, intercellular CO concentration, metabolites such as simple sugars, amino acids, aliphatic hydrocarbons, and the number of shrunken pith cells modulated in maize roots inoculated with NBRISH6. The NBRISH6 inoculation also improved the plant vegetative properties (root length, 33.80%; shoot length, 20.68%; root dry weight, 39.21%; shoot dry weight, 61.95%), shoot nutrients, xylem cells, root hairs, vapor pressure deficit (75%), intrinsic water-use efficiency (41.67%), photosynthesis rate (83.33%), and total chlorophyll (16.15%) as compared to the respective stress controls. This study provides valuable insights into mechanistic functions of PGPR in WS amelioration and promoting plant physiological response.
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http://dx.doi.org/10.1016/j.plaphy.2020.02.025DOI Listing
May 2020

Transcriptome and proteome analyses reveal selenium mediated amelioration of arsenic toxicity in rice (Oryza sativa L.).

J Hazard Mater 2020 05 16;390:122122. Epub 2020 Jan 16.

CSIR - National Botanical Research Institute, Council of Scientific and Industrial Research, Rana Pratap Marg, Lucknow, 226 001, India; Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi, 110 001, India. Electronic address:

Arsenic (As), a chronic poison and non-threshold carcinogen, is a food chain contaminant in rice, posing yield losses as well as serious health risks. Selenium (Se), a trace element, is a known antagonist of As toxicity. In present study, RNA seq. and proteome profiling, along with morphological analyses were performed to explore molecular cross-talk involved in Se mediated As stress amelioration. The repair of As induced structural deformities involving disintegration of cell wall and membranes were observed upon Se supplementation. The expression of As transporter genes viz., NIP1;1, NIP2;1, ABCG5, NRAMP1, NRAMP5, TIP2;2 as well as sulfate transporters, SULTR3;1 and SULTR3;6, were higher in As + Se compared to As alone exposure, which resulted in reduced As accumulation and toxicity. The higher expression of regulatory elements like AUX/IAA, WRKY and MYB TFs during As + Se exposure was also observed. The up-regulation of GST, PRX and GRX during As + Se exposure confirmed the amelioration of As induced oxidative stress. The abundance of proteins involved in photosynthesis, energy metabolism, transport, signaling and ROS homeostasis were found higher in As + Se than in As alone exposure. Overall, present study identified Se responsive pathways, genes and proteins involved to cope-up with As toxicity in rice.
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http://dx.doi.org/10.1016/j.jhazmat.2020.122122DOI Listing
May 2020

Appraisal of diversity and functional attributes of thermotolerant wheat associated bacteria from the peninsular zone of India.

Saudi J Biol Sci 2019 Nov 4;26(7):1882-1895. Epub 2016 Feb 4.

Division of Microbiology, Indian Agricultural Research Institute, New Delhi 110012, India.

The biodiversity of wheat associated bacteria was deciphered from the peninsular zone of India. A total of 264 isolated bacteria were analyzed through amplified ribosomal DNA restriction analysis (ARDRA, using three restriction enzymes I, I and III, which led to the clustering of these isolates into 12-16 groups for the different sites at >75% similarity index, adding up to 70 groups). 16S rRNA gene based phylogenetic analysis, revealed that all the bacteria belonged to three phyla Proteobacteria, Firmicutes, and Actinobacteria of 32 distinct species of 15 genera namely: , , , , , , , , , , , , , and Representative strains from each cluster were screened for plant growth promoting traits. Among plant growth promoting activities, siderophore producers were highest (15%), when compared to indole acetic acid producers (13%), Zn-solubilizers (11%), P-solubilizers (11%), ammonia (10%), hydrogen cyanide producers (9%), biocontrol (8%), N-fixers (7%), 1-aminocyclopropane-1-carboxylate deaminase (6%), GA producers (6%) and K-solubilizers (5%). Among 32 representative strains, , sp., , , , , sp., , , and exhibited more than six different plant growth promoting activities at high temperature. Thermotolerant bacterial isolates may have application as inoculants for plant growth promotion and biocontrol agents for crops growing at high temperature conditions.
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http://dx.doi.org/10.1016/j.sjbs.2016.01.042DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6864300PMC
November 2019

Bacillus amyloliquefaciens inoculation alters physiology of rice (Oryza sativa L. var. IR-36) through modulating carbohydrate metabolism to mitigate stress induced by nutrient starvation.

Int J Biol Macromol 2020 Jan 15;143:937-951. Epub 2019 Nov 15.

CSIR-National Botanical Research Institute (CSIR-NBRI), Rana Pratap Marg, Lucknow, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India. Electronic address:

To avoid disproportionate usage of chemicals in agriculture, an alternative eco-friendly strategy is required to improve soil fertility, and enhance crop productivity. Therefore, the present study demonstrates the role of plant beneficial rhizobacteria viz., Paenibacillus lentimorbus B-30488 (B-30488), Bacillus amyloliquefaciens SN13 (SN13), and their consortium in rice (Oryza sativa L. var. IR-36) facing nutrient deprivation. Parameters such as proline, total soluble sugar, relative water content, electrolytic leakage and malondialdehyde content were modulated in control rice seedlings as compared to treated under nutrient starved conditions. Bacterial inoculation not only significantly improved the agronomic parameters but also concentrations, uptake and partitioning of macro-micro nutrients. To disclose PGPR induced mechanisms to low nutrient stress tolerance, GC-MS analysis was performed. Overall 43 differential metabolites were characterized. Proline, glutamine, linolenic acid, malic acid, ribitol, propanoic acid and serine were accumulated in seedlings exposed to nutrient starvation. In PGPR inoculated rice glucose, fructose, mannose, glucitol, oleic acid, gulonic acid, raffinose, inositol were accumulated that induce metabolic and physiological parameters to reduce the impact of stress. Based on results SN13 was selected for gene expression analysis of metabolism-related genes that further affirmed the ability of PGPR to modulate carbohydrate metabolism in rice seedlings under suboptimum nutrient level.
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http://dx.doi.org/10.1016/j.ijbiomac.2019.09.154DOI Listing
January 2020

Realistic microstructure evolution of complex Ta-Nb-Hf-Zr high-entropy alloys by simulation techniques.

Sci Rep 2019 Nov 8;9(1):16337. Epub 2019 Nov 8.

TCS Research, Tata Research Development and Design Center, 54-B Hadapsar Industrial Estate, Hadapsar, Pune, 411013, Maharashtra, India.

Over last 15 years high-entropy alloys (HEAs) and complex concentrated alloys (CCAs) have gained much appreciation for their numerous superior properties. In this paper we have shown a novel simulation methodology to realistically predict the nanometer level local structural features of complex TaNbHfZr HEA. This involves prediction of the morphology of the short-range clustering (SRCs), their quantitative atomic composition at the nano level and the thermodynamic aspects. An alloy structure model containing 11664 atoms was created and this was subjected to structure evolution at 1800 °C. The structure evolution technique is based on a combined hybrid Monte Carlo and molecular dynamics (MC/MD) approach. The simulated results from this work are further validated against experiments and material characterizations reported in literature and done by high-resolution transmission electron micrograph (HRTEM) for the nano-level microstructure, atom probe tomography (APT) for the local chemical compositions and X-ray diffraction at synchrotron sources for the local lattice relaxation effects. This work qualitatively and quantitatively reproduces the materials characterization results reasonably well from the developed simulation methodologies. The structure evolution methods as described in this work are based on independent computer simulations and does not involve any manual intervention for input based on experiments on evolving SRCs. This work shows the potential of utilizing MC/MD based computational methods to reduce the number of costly experimental characterizations and accelerate the pace for materials development.
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http://dx.doi.org/10.1038/s41598-019-52170-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6841691PMC
November 2019

Betula utilis extract prolongs life expectancy, protects against amyloid-β toxicity and reduces Alpha Synuclien in Caenorhabditis elegans via DAF-16 and SKN-1.

Comp Biochem Physiol C Toxicol Pharmacol 2020 Feb 25;228:108647. Epub 2019 Oct 25.

Microbial Technology Division, CSIR-National Botanical Research Institute, Lucknow 226001, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India. Electronic address:

Betula utilis (BU), an important medicinal plant that grows in high altitudes of the Himalayan region, has been utilized traditionally due to it's antibacterial, hepatoprotective, and anti-tumor properties. Here, we demonstrated the longevity and amyloid-β toxicity attenuating activity of B. utilis ethanolic extract (BUE) in Caenorhabditis elegans. Lifespan of the worms was observed under both the standard laboratory and stress (oxidative and thermal) conditions. Effect of BUE was also observed on the attenuation of age-dependent physiological parameters. Further, gene-specific mutants and green fluorescent protein (GFP)-tagged strains were used to investigate the molecular mechanism underlying the beneficial effects mediated by BUE supplementation. Our results showed that BUE (50 μg/ml) extended the mean lifespan of C. elegans by 35.99% and increased its survival under stress conditions. The BUE also reduced the levels of intracellular reactive oxygen species (ROS) by 22.47%. A delayed amyloid-β induced paralyses was observed in CL4176 transgenic worms. Interestingly, the BUE supplementation was also able to reduce the α-synuclein aggregation in NL5901 transgenic strain. Gene-specific mutant studies suggested that the BUE-mediated lifespan extension was dependent on daf-16, hsf-1, and skn-1 but not on sir-2.1 gene. Furthermore, transgenic reporter gene expression assay showed that BUE treatment enhanced the expression of stress-protective genes such as sod-3 and gst-4. Present findings suggested that ROS scavenging activity, together with multiple longevity mechanisms, were involved in BUE-mediated lifespan extension. Thus, BUE might have potential to increase the lifespan and to attenuate neuro-related disease progression.
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http://dx.doi.org/10.1016/j.cbpc.2019.108647DOI Listing
February 2020

Nanometric NaYF as an Unconventional Support for Gold Catalysts for Oxidation Reactions.

ACS Omega 2019 Mar 26;4(3):5852-5861. Epub 2019 Mar 26.

Univ Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON-UMR 5256, 2 Avenue Albert Einstein, 69626 Villeurbanne, France.

The metal-support interaction plays an important role in gold catalysis. We employ here crystalline cubic (α-) and hexagonal (β-) phases of heterometallic fluoride NaYF nanoparticles (NPs), obtained by the decomposition of a single source precursor [NaY(TFA)(diglyme)] (TFA = trifluoroacetate), as nonoxide supports for gold catalysts. Using an isostructural gadolinium analogue, we also obtained doped α-NaYF:Gd and β-NaYF:Gd NPs. A successful deposition of ∼1% by weight gold NPs of average size 5-6.5 nm on these doped and undoped metal fluorides using HAuCl·3HO afforded Au/NaYF catalysts which were thoroughly characterized by using several physicochemical techniques such as X-ray diffraction, Brunauer-Emmett-Teller analysis, high-resolution transmission electron microscopy, energy-dispersive X-ray spectrometry, and X-ray photoelectron spectroscopy. A comparative study of the above catalysts for different oxidation reactions show that while for the aerobic oxidation of -stilbene in solution phase, they are either better (in terms of stilbene conversion) or at par (in terms of -stilbene oxide yield) in comparison to the reference catalyst Au/TiO of the World Gold Council, their activity toward CO oxidation reactions in gas phase remains much less than that of gold catalysts supported on metal oxides.
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http://dx.doi.org/10.1021/acsomega.9b00173DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6648813PMC
March 2019
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