On the optical properties of the Mn4+ ion in solids Brik, M.G.; Srivastava, A.M.
Journal of luminescence,
January 2013, 2013, 2013-1-00, 20130101, Letnik:
133, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
A review of the optical properties of Mn4+ ions in a number of host lattices is presented. As an example, detailed crystal field calculations of the Mn4+ energy levels in Na2SiF6 and K2SiF6 are ...reported and compared with the literature experimental data. Special attention is paid to the crystal field analysis of the observed features in relation to the structural data and peculiar features of the chemical bonding. A simple criterion is proposed, which can effectively and easily describe ionicity/covalency of the Mn4+-doped crystals. This criterion is based on the position of the sharp spin-forbidden 2Eg→4A2g emission line transition: if it is located above 15500cm−1 (below ∼645nm), the bonding is essentially ionic, while its location below 15500cm−1 (above ∼645nm), is suggestive of covalent bonding.
► Analysis of the spectroscopic data for Mn4+ ions in a number of crystals was performed. ► A criterion to distinguish between the covalent and ionic crystals was proposed. ► Mn4+ ion was shown to be a reliable probe for covalent effects.
Over India, heat waves occur during the summer months of April to June. A gridded daily temperature data set for the period, 1961-2013 has been analyzed to examine the variability and trends in heat ...waves over India. For identifying heat waves, the Excess Heat Factor (EHF) and 90(th) percentile of maximum temperatures were used. Over central and northwestern parts of the country, frequency, total duration and maximum duration of heat waves are increasing. Anomalous persistent high with anti-cyclonic flow, supplemented with clear skies and depleted soil moisture are primarily responsible for the occurrence of heat waves over India. Variability of heat waves over India is influenced by both the tropical Indian Ocean and central Pacific SST anomalies. The warming of the tropical Indian Ocean and more frequent El Nino events in future may further lead to more frequent and longer lasting heat waves over India.
This study presents an approach for security-constrained unit commitment (SCUC) with integration of an energy storage system (ESS) and wind generation. Compressed air energy storage (CAES) is ...considered as an alternative solution to store energy. For economical operation and control purposes, utilities with CAES are interested in the availability and the dispatch of CAES on an hourly basis, given the specific characteristics of CAES. The main contribution of this study is the development of enhanced SCUC formulation and solution techniques with wind power, CAES and multiple constraints including fuel and emission limit. Proposed approach allows simultaneous optimisation of the energy and the ancillary services. Case studies with eight-bus and 118-bus systems are presented to validate the proposed model. This study also contributes by conducting comprehensive studies to analyse the impact of CAES system on locational pricing, economics, peak-load shaving, transmission congestion management, wind curtailment and environmental perspective.
► Kinetics of degradation of HD with calcinations temperature of CuO. ► Effect of calcinations temperature on degradation product of HD. ► Decontamination of HD on CuO nanoparticle via elimination ...and hydrolysis. ► Application of CuO nanoparticle for degradation of HD. ► Decontamination of chemical warfare agents.
Present study investigates the potential of CuO nanoparticles calcined at different temperature for the decontamination of persistent chemical warfare agent sulphur mustard (HD) at room temperature (30
±
2
°C). Nanoparticles were synthesized by precipitation method and characterized by using SEM, EDAX, XRD, and Raman Spectroscopy. Synthesized nanoparticles were tested as destructive adsorbents for the degradation of HD. Reactions were monitored by GC–FID technique and the reaction products characterized by GC–MS. It was observed that the rate of degradation of HD decreases with the increase in calcination temperature and there is a change in the percentage of product of HD degradation. GC–MS data indicated that the elimination product increases with increase in calcination temperature whereas the hydrolysis product decreases.
The treatment of opioid withdrawal is an important area of clinical concern when treating patients with chronic, non-cancer pain, patients with active opioid use disorder, and patients receiving ...medication for opioid use disorder. Current standards of care for medically supervised withdrawal include treatment with μ-opioid receptor agonists, (eg, methadone), partial agonists (eg, buprenorphine), and α2-adrenergic receptor agonists (eg, clonidine and lofexidine). Newer agents likewise exploit these pharmacological mechanisms, including tramadol (μ-opioid receptor agonism) and tizanidine (α2 agonism). Areas for future research include managing withdrawal in the context of stabilising patients with opioid use disorder to extended-release naltrexone, transitioning patients with opioid use disorder from methadone to buprenorphine, and tapering opioids in patients with chronic, non-cancer pain.
Food security will be increasingly challenged by climate change, natural resource degradation, and population growth. Wheat yields, in particular, have already stagnated in many regions and will be ...further affected by warming temperatures. Despite these challenges, wheat yields can be increased by improving management practices in regions with existing yield gaps. To identify the magnitude and causes of current yield gaps in India, one of the largest wheat producers globally, we produced 30 meter resolution yield maps from 2001 to 2015 across the Indo-Gangetic Plains (IGP), the nation's main wheat belt. Yield maps were derived using a new method that translates satellite vegetation indices to yield estimates using crop model simulations, bypassing the need for ground calibration data. This is one of the first attempts to apply this method to a smallholder agriculture system, where ground calibration data are rarely available. We find that yields can be increased by 11% on average and up to 32% in the eastern IGP by improving management to current best practices within a given district. Additionally, if current best practices from the highest-yielding state of Punjab are implemented in the eastern IGP, yields could increase by almost 110%. Considering the factors that most influence yields, later sow dates and warmer temperatures are most associated with low yields across the IGP. This suggests that strategies to reduce the negative effects of heat stress, like earlier sowing and planting heat-tolerant wheat varieties, are critical to increasing wheat yields in this globally-important agricultural region.
Non-enzymatic glycation is the addition of free carbonyl group of reducing sugar to the free amino groups of proteins, resulting in the formation of a Schiff base and an Amadori product. ...Dihydroxyacetone (DHA) is one of the carbonyl species which reacts rapidly with the free amino groups of proteins to form advanced glycation end products (AGEs). The highly reactive dihydroxyacetone phosphate is a derivative of dihydroxyacetone (DHA), and a product of glycolysis, having potential glycating effects to form AGEs. The formation of AGEs results in the generation of free radicals which play an important role in the pathophysiology of aging and diabetic complications. While the formation of DHA-AGEs has been demonstrated previously, no extensive studies have been performed to assess the inhibition of AGE inhibitors at all the three stages of glycation (early, intermediate and late) using metformin (MF) and pyridoxamine (PM) as a novel inhibitor.
In this study we report glycation of human serum albumin (HSA) & its characterization by various spectroscopic techniques. Furthermore, inhibition of glycation products at all the stages of glycation was also studied. Spectroscopic analysis suggests structural perturbations in the HSA as a result of modification which might be due to generation of free radicals and formation of AGEs.
The inhibition in the formation of glycation reaction reveals that Pyridoxamine is a better antiglycating agent than Metformin at all stages of the glycation (early, intermediate and late stages).
► “State of the art” in the biological production of 1,3-PD, its separation & key strategic bottlenecks for research has been summarized. ► Bioprocess engineering aspects for 1,3-PD production have ...been highlighted. ► Key role of modelling & its use for 1,3-PD process optimization has been proposed.
1,3-propanediol (1,3-PD) is a chemical compound with myriad applications particularly as a monomer for the production of polyesters, polyethers and polyurethanes. It is a raw material for the production of biodegradable plastics, films, solvents, adhesives, detergents, cosmetics and medicines. Various strategies have been employed for the microbial production of 1,3-PD which include several bioprocess cultivation techniques facilitated by natural and/or genetically engineered microbes. Though 1,3-PD is produced in nature by the bioconversion of glycerol its production directly from sugars like glucose has been also made possible by the development of recombinant strains. This review presents the “state of the art” in the biotechnological production technologies of 1,3-PD particularly with respect to bioprocess engineering methods. It also highlights the significance of mathematical model-based approach for designing various bioreactor operating strategies to facilitate the improvement in 1,3-PD production. Attempt has also been made to focus on the protocols used for downstream processing of 1,3-PD and the associated problems. Finally concluding remarks on the future outlook on biobased 1,3-PD to reduce the dependence on disappearing fossil fuels are presented.
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