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Designing and synthesis of phosphine derivatives of Ru3(CO)12 – Studies on catalytic isomerization of 1-alkenes
Get PDFIn the present study, we have attempted to identify Sacubitril
derivatives as lead compounds for dormant tuberculosis. A
total of twenty-one compounds belongs to a series of the
Sacubitril derivatives 5(a–u) were synthesized using (2R,4S)-5-
([1,1’-biphenyl]-4-yl)-4-(amino)-2-methylpentanoic acid ethyl ester hydrochloride with different isocyanates and isothiocyanates. All the compounds structures were determined by 1 H & 13CNMR spectroscopy, mass spectrometry, and CHN analysis. Compound, 5r, the structure confirmed by single-crystal X-ray diffraction analysis (SXRD). The newly synthesized compounds were screened for their in vitro antituberculosis activity (antiTB) against dormant Mycobacterium tuberculosis H37Rv (ATCC27294). Among the twenty-one compounds, 5p and 5q were exhibited good potent anti-TB activity compared to the
standard drug Ethambutol. Further, the anti-TB activities of the
compounds (5p and 5q) were evaluated against M. tuberculosis
(Mtb) using the nutrient starvation model (NSM). Moreover,
these two compounds, 5p and 5q have shown significant
inhibition of growth of Mtb as compared to the control. To
determine the toxicity nature, the potent anti-TB active
compounds were evaluated against RAW 264.7 cells. Further,
the anti-TB activities of all these compounds have shown a
good correlation to their in-silico molecular docking analysis by
exhibiting strong interactions with the inhibitor Mur-B
Synthesis, structural and antibacterial activity of pure, Fe doped, and glucose capped ZnO nanoparticles
No full textIn this report, the structure, texture, and antibiotic nature of the synthesized ZnO nanoparticles have been studied using X-ray diffraction (XRD), Transmission electron microscope (TEM), and Fourier transform infrared spectroscopy (FTIR). The single wurtzite hexagonal crystal structure with their particle sizes in the 17–19 nm range was obtained. The particles were almost spherical. The octahedral peak from FTIR has been calculated at around 470–489 cm− 1 while the tetrahedral sites at 616 cm− 1. The defect and antibiotic nature of ZnO is found to be correlated
Vacuum Assisted Low Temperature Growth Of Perovskite Nanocrystals Reaching Near Unity Photoluminescence Quantum Yield
No full textIn this work, luminescent perovskite nanocrystals (PNCs) were grown by the modified hot-injection method under reduced pressure at low temperatures. This modified method utilizing the property of reduction of the boiling point of the solvent under reduced pressure. This proposed method facilitates the growth of high-quality nanocrystals (NCs) without a Schlenk line and inert environment. The synthesis temperature of these PNCs using this method is reduced by 30–40 °C compared to the conventional hot-injection method. Different PNCs starting from nanoplatelets to nanocubes and nanorods were successfully grown using this method. The morphology, structural and luminescence properties of the NCs which are grown by this modified hot-injection method depend on synthesis temperature. The average lifetime of the charge carriers in PNCs is estimated from the time-resolved photoluminescence (TRPL) measurements is of the order of 25–75ns. The nanocubes synthesized at 120 °C reaches nearly 100% photoluminescence quantum yield (PLQY) within the measurement error and also exhibit excellent stability. The aged nanocrystals synthesized at 120 °C retain 83% of their initial PLQY when exposed to an ambient atmosphere for one month. Besides, we have investigated the origin of the instability of these PNCs when exposed to an ambient atmosphere. It is evident from the X-ray diffraction (XRD) measurements the degradation of the PNCs via the formation of the Cs-rich by-product Cs4PbBr6. The main reason for the formation of the Cs-rich by-product is due to the limited solubility of PbBr2 at relatively low temperatures, which results in the vacancy formation of Pb and Br during synthesis. Another reason for the formation of Cs-rich by-product Cs4PbBr6 nanospheres is due to the ligand loss from the surface of the PNC which might cause the Pb and Br defects
NIR Luminescence Features Of Nd 3+ Ion In Lithium Antimonite Glass System
No full textGlasses of the composition 40Li2O‒(60-x)Sb2O3: xNd2O3(x = 0.2, 0.4, 0.6, 0.8 and 1.0 mol%) were synthesized by melt quenching technique. The structural and optical characteristics were investigated as a function of Nd2O3concentration. From the optical absorption spectra J-O intensity parameters (Ωλ, λ = 2,4 and 6) were evaluated; the parameters are found to be in the order: Ω2 > Ω6 > Ω4. The emission spectra recorded at λexc = 808 nm) exhibited three intense bands at 875 nm, 1053 nm and 1328 nm attributed to4F3/2 → 4I9/2,11/2,13/2 transitions, respectively. The intensity of 4F3/2 → 4I11/2 (1.053 μm) emission band is found to be the highest among the three bands. With increasing the concentration of Nd2O3 upto 0.8 mol%, intensity of all emission bands exhibited an increasing trend. Beyond 0.8 mol%, a decrease in the intensity of PL output is observed; this is attributed to concentration quenching losses and increased phonon losses. From emission spectra, various radiative parameters such as transition probability, AR, branching ratio β, and radiative life time, τR, were evaluated for all glass samples. The analysis of the results indicated glasses mixed with 0.8 mol% of Nd3+exhibited the highest efficiency of 1.053 μm emission. The reasons for such high efficiency were further identified using structural analysis of the host glass using IR spectral studies
Comprehensive microbiological studies on screening bacteria for self-healing concrete
No full textThe recent outbreak of coronavirus disease (COVID-19) has challenged the survival of human existence in the last 1 year.
Frontline healthcare professionals were struggling in combating the pandemic situation and were continuously supported with
literature, skill set, research activities, and technologies developed by various scientists/researchers all over the world. To handle the continuously mutating severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) requires amalgamation of conven- tional technology with emerging approaches. Nanotechnology is science, engineering, and technology dealing at the nanoscale level. It has made possible the development of nanomaterials, nano-biosensors, nanodrugs, and vaccines for diagnosis, therapy, and prevention of COVID-19. This review has elaborately highlighted the role of nanotechnology in developing various detection kits such as nanoparticle-assisted diagnostics, antibody assay, lateral flow immunoassay, nanomaterial biosensors, etc., in detection of SARS-CoV-2. Similarly, various advancements supervene through nanoparticle-based therapeutic drugs for inhibiting viral infection by blocking virus attachment/cell entry, multiplication/replication, and direct inactivation of the virus.
Furthermore, information on vaccine development and the role of nanocarriers/nanoparticles were highlighted with a brief
outlining of nanomaterial usage in sterilization and preventive mechanisms engineered to combat COVID-19 pandemic
Recovery of Lead as Lead Sulphide from Anode Slime using Hydrometallurgical Technique
No full textLead is produced from ores, concentrates and secondaries using pyrometallurgical process routes. Different hydrometallurgical techniques are also employed to recover lead as metal or its compound. In the present study, an attempt was made to recover lead from the anode slime (12.75% Pb and 18.50% Cu as major elements) that is obtained during electrorefining of copper. Before lead extraction, decopperization was carried out using very dilute sulphuric acid leaching, where Cu was completely removed. Lead was extracted using brine solution as the leachant. The maximum leaching efficiency of 80.66% was obtained using 35% brine solution under the conditions of 5% pulp density, 90 °C temperature and 1 h duration. Lead was further recovered from the brine leach solution as lead sulphide using sodium sulphide by precipitation technique. It is found that lead sulphide of high purity can be produced from anode slime
Syntheses of N‑Doped Carbon Quantum Dots (NCQDs) fromBioderived Precursors: A Timely Update
No full textAbstract and figures
The emergence of carbon quantum dots (CQDs) opens up new opportunities in different branches of science and technology primarily because of their conducive biocompatibility, tunable bandgaps, and unique optoelectronic properties, namely, photoluminescence (PL) and fluorescence. Although CQDs are given precedence in the literature, the large-scale sustainable synthesis and the purification of CQDs as well as the study of their effects on health and environment remain a challenge. Hence, more sustainable approaches are being developed to make this category of materials widely applicable, specifically in the context of replacing toxic metal-based QDs. Among the reported synthetic protocols employed to prepare CQDs while controlling their properties, the incorporation of various dopants, surface functionalities, and defects into CQDs offers great promises. Amongst the possibilities, nitrogen dopants contribute significantly due to their broader precursor scope, natural abundance in sustainable bioderived resources, and relatively straightforward and inexpensive synthetic protocols, leading to assorted combinations of nitrogen (N)-doped carbon quantum dots (NCQDs). Here, a brief survey is presented on the recent developments of strategies deployed for the preparation of bioderived NCQDs, emphasizing the uniqueness of the synthetic methodology, choice of precursors, and purification strategies. In addition, characterization, properties, and applications of the selected NCQDs are highlighted. The present status and challenges are also discussed along with the future directions
Studies on the impact of soaking time on a cryogenic processed and post tempered WC-Co insert
No full textIn the present work, commercially available tungsten carbide bonded with cobalt (WC-Co) which is used as a cutting tool is cryogenically treated at different holding periods in a deep subzero environment and evaluates the machining performance through dry turning. The results revealed that 24 h deep cryo
soaked WC-Co insert shows improved observation is because of the presence of (N) eta carbide particles and fine distribution of micro grains and it’s confirmed by SEM micrograph. Higher the soaking leads to irregular grain growth and a deficiency in the formation/distribution of eta carbide particles that affect
the hardness of the too
Influence of nitrogen and phosphorus on microalgal growth, biomass, lipid, and fatty acid production: An overview
No full textMicroalgae can be used as a source of alternative food, animal feed, biofuel, fertilizer,cosmetics, nutraceuticals and for pharmaceutical purposes. The extraction of organic constituents
from microalgae cultivated in the different nutrient compositions is influenced by microalgal growth rates, biomass yield and nutritional content in terms of lipid and fatty acid production. In this context, nutrient composition plays an important role in microalgae cultivation, and depletion and excessive sources of this nutrient might affect the quality of biomass. Investigation on the role of nitrogen and phosphorus, which are crucial for the growth of algae, has been addressed. However, there are challenges for enhancing nutrient utilization efficiently for large scale microalgae cultivation. Hence,
this study aims to highlight the level of nitrogen and phosphorus required for microalgae cultivation and focuses on the benefits of nitrogen and phosphorus for increasing biomass productivity of microalgae for improved lipid and fatty acid quantities. Furthermore, the suitable extraction methods that can be used to utilize lipid and fatty acids from microalgae for biofuel have also been reviewed
Nanotechnology: an emerging approach to combat COVID-19
No full textCoronavirus disease 2019 (COVID-19) is caused by a Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2),
which is a positive-strand RNA virus. The SARS-CoV-2 genome and its association to SAR-CoV-1 vary from ca. 66 to 96%
depending on the type of betacoronavirideae family members. With several drugs, viz. chloroquine, hydroxychloroquine,
ivermectin, artemisinin, remdesivir, azithromycin considered for clinical trials, there has been an inherent need to fnd distinctive antiviral mechanisms of these drugs. Curcumin, a natural bioactive molecule has been shown to have therapeu-tic potential for various diseases, and its efect on COVID-19 is also currently being explored. In this study, we show the binding potential of curcumin targeted to a variety of SARS-CoV-2 proteins, viz. spike glycoproteins (PDB ID: 6VYB), nucleocapsid phosphoprotein (PDB ID: 6VYO), spike protein-ACE2 (PDB ID: 6M17) along with nsp10 (PDB ID: 6W4H) and RNA dependent RNA polymerase (PDB ID: 6M71) structures. Furthermore, representative docking complexes were validated using molecular dynamics simulations and mechanistic studies at 100 ns was carried on nucleocapsid and nsp10 proteins with curcumin complexes which resulted in stable and efcient binding energies and correlated with that of docked
binding energies of the complexes. Both the docking and simulation studies indicate that curcumin has the potential as an antiviral against COVID-19