COMPARATIVE PHARMACOGNOSTIC STUDIES OF ROOTS OF ASHWAGANDHA (WILD, NAGORI AND POSHITHA VAR)

Background: Ashwagandha is a very well-known herb in Ayurveda. It is widely used in pharmaceutical, cosmetic, agricultural, food industries, and is a constituent of over 200 Ayurvedic formulations. The annual demand of Ashwagandha is 7000 tons but its actual availability is just 1500 tons, this demand is not met by using the wildly grown Ashwagandha. To meet this demand, it has been brought under cultivation many centuries ago, in India. Numerous cultivated varieties of Ashwagandha are developed for high yield and better quality roots. Amongst them, Nagori Ashwagandha is a popular variety, cultivated for its demand. Poshitha Ashwagandha is a high yielding and improved variety released by CSIR-CIMAPS. The current study aims at comparing the roots of wildly grown Ashwagandha, Nagori Ashwagandha and Poshitha Ashwagandha, pharmacognostically. Methodology: The study deals with macroscopic parameters, microscopic study of transverse sections physicochemical, phytochemical analysis and powder microscopy of roots of the three varieties of Ashwagandha. Results: Significant macroscopic differences were noted between the wild and the two cultivated varieties of Ashwagandha roots, there was no much variation in the physico-chemical and phyto-chemical parameters amongst the three, also there was no much difference found between the two cultivated varieties- morphologically and phyto-chemically

High-Entropy Alloys as Catalysts for the CO2 and CO Reduction Reactions: Experimental Realization

Conversion of carbon dioxide into selective hydrocarbon using a stable catalyst remains a holy grail in the catalysis community. The high overpotential, stability, and selectivity in the use of a single-metal-based catalyst still remain a challenge. In current work, instead of using pure noble metals (Ag, Au, and Pt) as the catalyst, a nanocrystalline high-entropy alloy (HEA: AuAgPtPdCu) has been used for the conversion of CO2 into gaseous hydrocarbons. Utilizing an approach of multimetallic HEA, a faradic efficiency of about 100% toward gaseous products is obtained at a low applied potential (−0.3 V vs reversible hydrogen electrode). The reason behind the catalytic activity and selectivity of the high-entropy alloy (HEA) toward CO2 electroreduction was established through first-principles-based density functional theory (DFT) by comparing it with the pristine Cu(111) surface. This is attributed to the reversal in adsorption trends for two out of the total eight intermediates—*OCH3 and *O on Cu(111) and HEA surfaces

Suppression of σ-phase in nanocrystalline CoCrFeMnNiV high entropy alloy by unsolicited contamination during mechanical alloying and spark plasma sintering

CoCrFeMnNiV high entropy alloy (HEA) exhibits a high content of σ-phase (70 vol%) when produced by casting route. In the present work, a combination of mechanical alloying (MA) and spark plasma sintering (SPS) has been used to synthesize nanocrystalline CoCrFeMnNiV HEA where the formation of σ-phase has been avoided. Electron microscopy and atom probe tomography analysis indicated the formation of FCC structured HEA matrix along with (Cr,V) carbide (15 vol%) precipitation, without the presence of σ-phase in SPS processed alloy. Gibbs energy vs composition (G-x) diagrams of binary subsystems and possible carbides and oxides substantiate the absence of σ-phase during SPS of CoCrFeMnNiV alloy. Thus, the unsolicited contamination during MA-SPS route proves beneficial in suppressing the complex phase formation. © 2020 Elsevier B.V

A Meticulous Review of Clinical Utility of Madhura Rasa as Expounded in Charaka Samhitha

Ayurveda, the science of life, is one of the oldest medical sciences in the world. One among the Great Trio of Ayurveda is Charaka Samhitha by Agnivesha. It is constituted of 120 chapters spread across 8 Sthaanas (sections). The review of references of Madhura across Charaka Samhitha was started by thorough screening using E–Samhitha where Madhura or its synonyms were searched for. The references obtained were tabulated with brief context, application and usage. The literature search of Charaka Samhitha proffered 104 references pertaining to clinical utility of Madhura Rasa were Madhura /its synonyms were directly mentioned. From the 104 references of Madhura Rasa, 14 contexts pointed it out as Nidana – causative factor, 31 contexts as Lakshana – Signs/symptoms/properties and 59 contexts highlighted it as a Chikitsa – treatment/essential regimen. Of these 104 references, 93 were for internal usage and 11 for external utility. Further work towards use of appropriate drugs from Madhura Skandha is essential for beneficial and effective use of Madhura Rasa in clinical practice

Formic acid and methanol electro-oxidation and counter hydrogen production using nano high entropy catalyst

Renewable harvesting of clean energy using the benefits of multi-metallic catalytic materials of high entropy alloy (HEA, equimolar CueAgeAuePtePd) from formic acid with minimum energy input has been achieved in the present investigation. The synergistic effect of pristine elements in the multimetallic HEA drives the electro-oxidation reaction towards non-carbonaceous pathway. The atomistic based simulations based on DFT rationalize the distinct lowering of the d-band center for the individual atoms in the HEA as compared to the pristine counterparts. Further this catalytic activity of the HEA has also been extended to methanol electro-oxidation to show the unique capability of the novel catalyst. The nanostructured HEA, prepared using a combination of casting and cryomilling techniques can further be utilized as the fuel cell anode in the direct formic acid/methanol fuel cells (DFFE)

Atomic scale compositional characterization of a nanocrystalline AlCrCuFeNiZn high entropy alloy using atom probe tomography

We have studied a nanocrystalline AlCrCuFeNiZn high entropy alloy synthesized by ball milling followed by hot compaction at 600 C for 15 min at 650 MPa. X ray diffraction reveals that the mechanically alloyed powder consists of a solid solution body centered cubic bcc matrix containing 12 vol. face centered cubic fcc phase. After hot compaction, it consists of 60 vol. bcc and 40 vol. fcc. Composition analysis by atom probe tomography shows that the material is not a homogeneous fcc bcc solid solution but instead a composite of bcc structured Ni Al , Cr Fe and Fe Cr based regions and of fcc Cu Zn based regions. The Cu Zn rich phase has 30 at. Zn a brass composition. It segregates predominantly along grain boundaries thereby stabilizing the nanocrystalline microstructure and preventing grain growth. The Cr and Fe rich bcc regions were presumably formed by spinodal decomposition of a Cr Fe phase that was inherited from the hot compacted state. The Ni Al phase remains stable even after hot compaction and forms the dominant bcc matrix phase. The crystallite sizes are in the range of 20 30 nm as determined by transmission electron microscopy. The hot compacted alloy exhibited very high hardness of 870 10 HV. The results reveal that phase decomposition rather than homogeneous mixing is prevalent in this alloy. Hence, our current observations fail to justify the present high entropy alloy design concept. Therefore, a strategy guided more by structure and thermodynamics for designing high entropy alloys is encouraged as a pathway towards exploiting the solid solution and stability idea inherent in this concept

A combined electron microscopy, atom probe tomography and small angle X-ray scattering study of oxide dispersion strengthened 18Cr ferritic steel

Dispersion of nano Y2O3 (0.35 wt.%) in 18Cr ferritic steel (Fe–18Cr–2.33W–0.34Ti) was achieved by high energy ball milling of pre–alloyed powders after 6 h. The severe deformation induced nano-structuring during ball milling led to metastable solid solution formation, which gets stabilized during consolidation by upset forging and hot extrusion. Transmission electron microscopy, atom probe tomography and small angle X–ray scattering were combined to comprehensively characterize the crystal structure, morphology and the chemical composition of the dispersoids. Accordingly, the dispersoids of the type Y2Ti2O7 with cuboidal shape and Fd3¯m diamond cubic crystal structure having a lattice parameter of 1.01 nm were observed. The plastic deformation behavior of ODS steels at different operating temperatures was studied using the tensile test and the results were correlated with the size and morphology of the dispersoids. © 2020 Elsevier Inc