Browsing by Author "A.K. Choudhary"

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Effect of dopant (Li+, Mg2+ and Bi3+) on the photoluminescence emission intensity of Eu3+ doped CaAl2O4 phosphor: Application to white LEDs
(Elsevier B.V., 2023) A.K. Choudhary; A. Roy; P.K. Yadav; S.B. Rai
In this work, we have investigated the photoluminescence (PL) emission properties of Eu3+ doped CaAl2O4 in the presence of singly, doubly and triply ionized dopant ions i.e., Li+, Mg2+ and Bi3+ ions. The phosphor samples were synthesized by the high-temperature solid-state reaction process at 1473 K. The crystalline phase, crystallinity and surface morphology of Li+, Mg2+ and Bi3+ ions doped 0.01Eu3+:CaAl2O4 phosphor were examined and confirmed by X-Ray diffraction (XRD) and scanning electron microscope (SEM) measurements. The different vibrational groups and their corresponding vibrational frequencies were measured by Fourier transform infrared (FTIR) technique. The 0.01Eu3+:CaAl2O4 phosphor emits intense red emission at 616 nm on excitations with 393 nm (Eu3+ line) and by the charge transfer band (Eu3+-O2-) at 262 nm. The overall PL emission intensity of 0.01Eu3+:CaAl2O4 phosphor on excitation with 393 nm is found to increase almost 2.8 times in the presence of Li+ than other dopants. The emission intensity are increased in case of Li+ and Mg2+ doping due to crystallinity, charge compensation and the asymmetry created around the Eu3+ ions in the phosphors matrix. However, in case of Bi3+ ion, the emission intensity decreases on 393 nm excitation. In the presence of Bi3+ ion the intense red emission is observed due to energy transfer from Bi3+ (3P1→1S0) to Eu3+ ion on λexc = 294 nm. The lifetime study were carried in each case which are in accordance with the PL emission behaviour of Li+, Mg2+ and Bi3+ ions doped 0.01Eu3+:CaAl2O4 phosphor. The CIE color coordinates, correlated color temperature (CCT) and color purity have been calculated, which shows highly pure red color in the warm light region. The 0.01Eu3+:0.10Li+:CaAl2O4 phosphor may be used in displays devices, photonic devices, solid state lighting as red light emitting source. © 2022 Elsevier B.V.
Enhanced upconversion emission and temperature sensor sensitivity in presence of Bi3+ ions in Er3+/Yb3+ co-doped MgAl2O4 phosphor
(Elsevier Ltd, 2018) A.K. Choudhary; A. Dwivedi; A. Bahadur; T.P. Yadav; S.B. Rai
Mg0(.95-x)ErxYb0.05Al2O4 (x = 0.3, 0.5, 0.7, 1.0, and 1.5 mol%) and Mg(0.943-y)Er.007Yb0.05BiyAl2O4 (y = 2, 5, 7, 10, and 15 mol%) phosphor samples have been synthesized by solid state reaction method. The X-ray diffraction (XRD) measurements confirm the cubic phase formation and shift in peaks position due to Bi3+ ions doping. The surface morphology of the prepared samples has been studied by scanning electron microscopy (SEM) measurement. The FTIR spectra reveal the information about the vibrational bands arising due to different molecules or species/groups. The Mg(0.943-y)Er0.007Yb0.05Al2O4 phosphor sample gives an intense upconversion (UC) green emission peaks centered at ~ 521 and 543 nm due to (4S3/2, 2H11/2)→4I15/2 transitions and the weak red emission at 660 nm due to 4F9/2→4I15/2 transition. The emission intensity of green bands is enhanced by 30 times and the red band by 10 times on addition of Bi3+ in Mg (0.943) Er0.007Yb0.05Al2O4 phosphor. This increase in emission intensity also enhances the fluorescence intensity ratio (FIR) of two thermally coupled levels emitting green radiation (i.e. FIR = I521/I543). The large variations of FIR with temperature clearly suggest that the material can be used as temperature sensor. The temperature sensing sensitivity is found to be quite high in presence of Bi3+ ions. The laser induced optical heating with pump power has also been observed in this material. © 2018 Elsevier Ltd and Techna Group S.r.l.
Enhanced upconversion emission of Er3+/Yb3+ and Er3+/Yb3+/Zn2+ doped calcium aluminate for use in optical thermometry and laser induced optical heating
(IOP Publishing Ltd, 2018) A.K. Choudhary; S.K. Singh; A. Dwivedi; A. Bahadur; S.B. Rai
There are two key factors to design an efficient green upconversion (UC) emission based optical sensor for temperature. The primary need is to develop a thermally stable and economical material, for a stable sensor, and the second essence is to get an efficient green UC emission, for high sensitivity of the sensor. The proof of this concept is demonstrated on a model system CaAl2O4: Er3+, co-doped with Yb3+ and Zn2+. UC emission of Er3+ion is enhanced, primarily, through co-operative energy transfer from Yb3+to Er3+ ions. Secondly, we prove that, incorporation of Zn2+ ions alters local crystal field environment around Er3+ ions which causes an enhancement in green UC emission. The variation in intensity ratio of 2H11/2 → 4I15/2 (green) and 4S3/2 → 4I15/2 (green) transitions with temperature is studied to report the sensing property. We show that, sensitivity becomes better with an increase in UC efficiency and the best sensitivity is attained for CaAl(0.793)2Er0.007Yb0.05Zn0.15O4 sample, ∼0.0154 K-1 at 308 K. The obtained result is compared with other works and implies its better suitability. Further, the laser induced optical heating is also observed. The laser induced optical heating has been observed experimentally at 400 K above 1 W laser power. This has been further verified by theoretical justification of heating at various pump powers. © 2018 IOP Publishing Ltd.
Enhanced upconversion from Er 3+ /Yb 3+ co-doped alkaline earth aluminates phosphor in presence Zn 2+ : A comparative study
(Elsevier B.V., 2019) A.K. Choudhary; A. Dwivedi; A. Bahadur; S.B. Rai
In the present work, the upconversion emission spectra of Er 3+ /Yb 3+ co-doped CaAl 2 O 4 (CAO), SrAl 2 O 4 (SAO) and BaAl 2 O 4 (BAO) phosphor samples have been studied in absence and presence of Zn 2+ . The samples were synthesized using high temperature solid state reaction technique at 1623 K. The X-ray diffraction (XRD) measurements have been carried out to verify the pure phase formation in all the three cases. Whereas the CAO and SAO samples show the monoclinic phase, the BAO sample shows hexagonal phase. The surface morphology of the three phosphor samples has been studied by scanning electron microscopy (SEM) technique. The Fourier-transform infrared (FTIR) and Raman measurements show the vibrational bands due to different groups present in the samples. The upconversion emission spectra of all the three samples show green and red emissions bands due to Er 3+ ion on excitation with 980 nm laser. However, it is interesting to note that CAO phosphor emits very intense green and weak red emissions, the SAO and BAO phosphors give intense red and weak green emissions. However, the upconversion emission intensity (green as well as red both) in all the three samples is enhanced several times in presence of Zn 2+ ions. The mechanism involved in UC emissions has been explained by partial energy level diagram. © 2019
Optical properties of Er3+, Yb3+ co-doped calcium zirconate phosphor and temperature sensing efficiency: Effect of alkali ions (Li+, Na+ and K+)
(Elsevier Ltd, 2018) A. Maurya; A. Bahadur; A. Dwivedi; A.K. Choudhary; T.P. Yadav; P.K. Vishwakarma; S.B. Rai
The Er3+/Yb3+ co-doped calcium zirconate phosphors have been synthesized through solid state reaction method. The structural characterizations confirm the crystalline nature of the phosphor. The Er3+, Yb3+ co-doped phosphor emits intense green emission centered at 523 and 544 nm due to the 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transitions, respectively and weak red emission at 662 nm due to 4F9/2 → 4I15/2 transition of Er3+ on excitation with 976 nm radiation. The emission intensity of the green band dominates over the red band. When the alkali ions (Li+, Na+, K+) are added in the Er3+/Yb3+ co-doped phosphor, the emission intensities of bands enhance significantly. The fluorescence intensity ratio correspond to 523 and 544 nm peaks at different temperatures have been obtained which confirm the temperature sensing ability of the samples. In presence of alkali ions, the temperature sensor sensitivity increases and is maximum for K+ co-doped phosphor. It is found that the energy gap between 2H11/2 and 4S3/2 levels increases with crystallinity in order of K+>Na+>Li+> without alkali ion. Thus, the Li+, Na+ and K+ incorporated Er3+, Yb3+ co-doped calcium zirconate phosphor may be useful for photonic devices and temperature sensor. © 2018 Elsevier Ltd
Optical properties of Tm3+/Yb3+ co-doped XAl2O4 (X = Mg, Ca, Sr and Ba) phosphors: Effect of co-doping of alkaline earths on the radiative as well as non-radiative behaviours
(Elsevier Ltd, 2021) A.K. Choudhary; A. Dwivedi; A. Rai; A. Bahadur; S.B. Rai
Tm3+-Yb3+ co-doped alkaline earths aluminate phosphors of the type XAl2O4 (X = Mg, Ca, Sr and Ba) are synthesized using solid state reaction method. The crystal structure and the phase of all these phosphor materials are confirmed by X-ray diffraction (XRD) measurements. The surface morphologies of all the samples are monitored by Scanning Electron Microscope (SEM) technique. The Ultraviolet (UV)-visible-near-IR region (NIR) absorption spectra show sharp f-f electronic transitions of Tm3+ and Yb3+ ions which are more prominent in CaAl2O4:Tm3+,Yb3+ phosphor. The upconversion (UC) emission spectra of the samples have been measured which give intense blue and NIR emissions on excitation with 980 nm radiation. It is observed that CaAl2O4:Tm3+,Yb3+ phosphor gives better UC emission in blue as well as NIR region than the others. We have also monitored the UC emission spectra of CaAl2O4:Tm3+, Yb3+ in the presence of other alkaline earths metals (i.e. Mg2+, Sr2+ and Ba2+ ions) as sensitizer. It is found that Mg2+ ion is a better enhancer for UC emission in CaAl2O4:Tm3+,Yb3+ phosphor (upto ten times) than the others. The spectral and color purity are found to be maximum for CaAl2O4:Tm3+,Yb3+,10Mg2+ phosphor. The laser induced optical heating is observed quantitatively in CaAl2O4:Tm3+,Yb3+,xMg2+ (x = 0, 5, 10 and 15 mol%) phosphors on excitation with 980 nm radiation. Thus, the maximum color and spectral purity for blue region in CaAl2O4:Tm3+,Yb3+,Mg2+ phosphor may be applicable as blue LED as well as the laser induced optical heating can be used for the application in cancer treatment based on opto-thermal therapy and as an optical heater. © 2021 Elsevier B.V.
Petrogenesis of end-Cretaceous/Early Eocene lamprophyres from the Deccan Large Igneous Province: Constraints on plume-lithosphere interaction and the post-Deccan lithosphere-asthenosphere boundary (LAB) beneath NW India
(Elsevier B.V., 2019) Rohit Pandey; Ashutosh Pandey; N.V. Chalapathi Rao; B. Belyatsky; A.K. Choudhary; B. Lehmann; Dinesh Pandit; Prashant Dhote
We present petrology, geochemistry and radiogenic isotope (Sr and Nd) data of thirteen post-Deccan lamprophyre dykes in the Narmada rift zone from the Chhotaudepur alkaline province of the Deccan Large Igneous Province (DLIP). Mineralogically, these dykes show affinity towards alkaline (sannaite and camptonite) as well as ultramafic (damtjernite) varieties of lamprophyres. Their major oxides and certain trace element ratios increase with increasing silica content highlighting the strong influence of fractionation processes. Their Nb/U and Ce/Pb ratios are similar to the mantle array defined by MORBs and OIBs and suggests an uncontaminated nature. Major oxide (K2O, Na2O, SiO2 and TiO2) contents show geochemical similarity towards shoshonitic volcanic series, whereas elevated Zr/Hf and Nb/La coupled with suppressed Rb/Nb and Zr/b display their affinity towards HIMU-type intraplate basalts. Their radiogenic initial 87Sr/86Sr (0.706034–0.710582) and sub-chondritic initial ɛNd (−8.6 to 2.1) are akin to those of the (i) ca. 65 Ma Ambadongar carbonatite, NW India, and (ii) ca. 65 Ma orangeites from Bastar Craton, central India, highlighting an enriched lithospheric mantle source. REE inversion modeling suggests ~3% enrichment of an undepleted mantle followed by small degrees of melting of this enriched mantle source are sufficient- as in the case of ocean island basalts (OIB)- to reproduce their observed REE concentrations. Their TDM Nd model ages (564–961 Ma) are consistent with widespread convergent margin-related magmatism during the amalgamation of the Rodinia supercontinent. We propose that enriched lithospheric mantle developed during the Neoproterozoic was metasomatized by small-volume CO2-rich melts imparting a HIMU-type geochemical character during Late Cretaceous, when the mantle plume (viz., Réunion) responsible for the flood basalt eruption, impinged at the base of the NW Indian lithosphere. From the presence of F-rich apatite and high K/Rb in mica, we infer the (i) presence of F-phlogopite in their source regions, and (ii) that the depth of post-Deccan lithosphere-asthenosphere boundary (LAB) beneath NW India was at least ~100 km at ca. 65 Ma. © 2019 Elsevier B.V.
Petrology, 40Ar/39Ar age, Sr-Nd isotope systematics, and geodynamic significance of an ultrapotassic (lamproitic) dyke with affinities to kamafugite from the easternmost margin of the Bastar Craton, India
(Springer-Verlag Wien, 2016) N. V. Chalapathi Rao; Atiullah; R. Burgess; Purnendu Nanda; A.K. Choudhary; Samarendra Sahoo; B. Lehmann; Ngazipmi Chahong
We report the mineralogy, bulk-rock geochemistry, 40Ar/39Ar (whole-rock) age and radiogenic (Sr and Nd) isotope composition of an ultrapotassic dyke from Sakri (Nuapada lamproite field) located at the tectonic contact between the easternmost margin of the Bastar craton and Eastern Ghats Mobile Belt, India. The Sakri dyke has a mineralogy which strongly resembles a lamproite sensu stricto (viz.,Ti-rich phlogopite, Na-poor diopside, Fe-rich sanidine, ulvospinel trend and Sr-rich apatite). However, its bulk-rock major element geochemical characteristics (viz., extreme silica-undersaturated nature) resemble sensu lato kamafugite from Toro Ankole, Uganda, East African Rift, and Alto Paranaiba Province, Brazil. The Sakri dyke also displays certain compositional peculiarities (viz., high degree of evolution of mica composition from phlogopite to biotite, elevated titanium and aluminum in clinopyroxene and significantly lower bulk Mg#) when compared to the ultrapotassic rocks from various Indian cratons. 40Ar/39Ar dating gave a plateau age of 1045 ± 9 Ma which is broadly similar to that of other Mesoproterozoic (i) lamproites from the Bastar and Bundelkhand cratons, and (ii) kimberlites from the Eastern Dharwar craton. Initial bulk-rock Sr (0.705865–0.709024) and Nd (0.511063–0.511154) isotopic ratios reveal involvement of an ‘enriched’ source region with long-term incompatible element enrichment and a depleted mantle (TDM) Nd model age of 2.56 Ga straddling the Archaean-Proterozoic chronostratigraphic boundary. The bulk-rock incompatible trace element ratios (Ta/Yb, Th/Yb, Rb/Ba and Ce/Y) of the Sakri ultrapotassic dyke negate any significant influence of crustal contamination. Small-degree melting (1 to 1.5 %) of a mixed garnet-facies and spinel-facies phlogopite lherzolite can account for its observed REE concentrations. Whereas the emplacement of the Sakri ultrapotassic dyke is related to the amalgamation of the supercontinent of Rodinia, its overlapping geochemical characteristics of lamproite and kamafugite (also displayed by two other lamproites of the Nuapada field at Amlidadar and Parkom) are linked to the emplacement in a unique geological setting at the craton-mobile belt contact and hence of geodynamic significance. © 2015, Springer-Verlag Wien.
Photoluminescence behavior of Eu3+?doped XAl2O4 (X?=?Mg, Ca, Sr and Ba) phosphors: a comparative study
(Institute of Physics, 2022) A.K. Choudhary; A. Dwivedi; S.B. Rai
In this work, the Eu3+ doped stuffed tridymite type structure of alkaline earths aluminate i.e. XAl2O4 (X?=?Mg, Ca, Sr and Ba) phosphor materials have been synthesized by conventional high temperature solid state reaction method at 1623 K. The Samples were structurally and morphologically characterized by x-ray diffraction (XRD) and Scanning electron microscope (SEM) measurements. The vibrational behavior of the phosphor samples were investigated by Fourier transform infrared (FTIR) measurements. The phosphor samples emit intense red emission in 610-615nmrange due to 5D0-7F2 transition of Eu3+ ion on excitation with charge transfer band (CTB) wavelength arising due to Eu3+-O2- and also by the discrete bands of Eu3+ ions .The decay time of 5D0 level of Eu3+ ion were recorded on excitation with 393nmand by the CTB wavelength for all the four samples. The optimized 1 mol% Eu3+ doped CaAl2O4 phosphor exhibits optimum emission intensity and color purity under the excitation with 393nmthan others. The decay time is also found to be larger in the case of Eu3+ doped CaAl2O4 phosphor sample. Therefore, Eu3+ doped CaAl2O4 phosphor may be promising material for red color light emitting applications and white light generation. 2022 IOP Publishing Ltd. © 2022 IOP Publishing Ltd. All rights reserved.
Redox imbalance disrupts spikelet fertility in rice: A study under stage-specific and multi-stage drought in eastern Indo-Gangetic plain
(Elsevier B.V., 2023) Santosh Kumar; Sahana Basu; A.K. Choudhary; J.S. Mishra; Surajit Mondal; Shashi Shekhar; S.K. Dwivedi; Rakesh Kumar; Surbhi Kumari; Narayan Bhakta; Sanjeev Kumar; Ujjwal Kumar; Arvind Kumar; Gautam Kumar
To support the increasing food demand of the drought-prone eastern Indo-Gangetic plain (EIGP), we assessed the effects of natural drought stress on the individual (seedling stage drought; SSD, vegetative stage drought; VSD, reproductive stage drought; RSD) as well as the multiple growth stages (multi-stage drought; MSD) of twenty-four rice genotypes (n = 24) under field conditions for two consecutive rice growing seasons (2019–2020). High temperature and low rainfall during both the trial years exerted moderate to severe drought stress to the rice genotypes leading to average grain yield reduction of 43.5%, 28.9%, 59.3%, and 69.9% under SSD, VSD, RSD, and MSD conditions, respectively. The present study also revealed that drought stress caused enhanced accumulation of reactive oxygen species (ROS) in the spikelets of rice genotypes thereby, impeding the spikelet fertility. The promising rice genotypes showed an average decrease of 3.18%, 4.83%, 13.9%, and 13.06% in spikelet fertility under SSD, VSD, RSD, and MSD conditions, respectively. Identified promising rice genotypes, IR83929-B-B-291–2–1–1–2, IR93827–29–1–1–2 and IR84899-B-183–20–1–1–1 showed extreme drought tolerance and better maintained photosynthetic rate, stomatal conductance, relative water content, membrane stability index, and total chlorophyll content under drought conditions irrespective of growth stages. Following the study, drought tolerance in the tolerant rice genotypes was associated with increased antioxidant enzyme mediated efficacious ROS detoxification, which contributed in maintaining pollen viability and spikelet fertility. Overall, the study identified drought tolerant rice genotypes for EIGP and established a comprehensive understanding of the complexity and plasticity of the rice genotypes under stage-specific and cumulative drought stress. © 2022 Elsevier B.V.
Rift-associated ultramafic lamprophyre (damtjernite) from the middle part of the Lower Cretaceous (125 Ma) succession of Kutch, northwestern India: Tectonomagmatic implications
(Elsevier B.V., 2018) Rohit Pandey; N.V. Chalapathi Rao; Prashant Dhote; Dinesh Pandit; A.K. Choudhary; Samarendra Sahoo; B. Lehmann
Mineralogical, geochemical and isotopic (Sr and Nd) studies on the recently reported ca. 124 Ma ‘anorogenic lamproite’ dyke from the Palanpur area, Kutch seismogenic rift zone, northwestern India, are presented. We propose a new classification for the dyke as a damtjernite (ultramafic lamprophyre; UML) based on its porphyritic-panidiomorphic texture, abundance of phlogopite, presence of nepheline in the groundmass, and the composition of liquidus phases such as olivine, phlogopite, magnetite, and clinopyroxene (diopside). The Palanpur UML is primitive (Mg# = 74–77), silica-undersaturated (SiO2 <40 wt.%), potassic to slightly sodic in nature, and is strikingly similar to the ∼69 Ma UML dykes and sills of the Tethyan Indus suture zone, which are considered as the earliest yet known manifestations of the Deccan Large Igneous Province (LIP). Bulk-rock (87Sr/86Sr)i (0.70460–0.70461) and ɛNd(t) (+2.56 to −0.69) of the Palanpur UML signify derivation from a slightly depleted mantle source similar to that of asthenospheric magmas such as OIB. This is further attested to by the high incompatible trace element ratios (viz., La/Ba, Nb/U, Nb/La and Ta/Yb) that are typical of plume-type magmas. However, the Neoproterozoic TDM depleted mantle Nd model ages (∼655–919 Ma) also necessitate some involvement of a lithospheric mantle component in its genesis. High bulk-rock Fe2O3 t and TiO2 contents require the involvement of a fertile peridotitic mantle source, whereas high La/Yb (60–80) implies a control by residual garnet. Higher Rb/Sr and lower Ba/Rb suggest phlogopite as a residual phase and high Nb and lower La/Sm favour carbonatite, rather than silicate melt as metasomatising agent. Low degrees of partial melting of a primitive garnet lherzolite mantle can account for the observed REE patterns in the Palanpur UML. The Palanpur UML shares a temporal similarity to the Kerguelen plume-derived Rajmahal basalts and associated alkaline rocks from the eastern India. The tectonomagmatic significance of its emplacement during the mid-Cretaceous vis-à-vis various models involving the timing of eruption of the Deccan and the Rahmahal Traps and the rifting in the Kutch basin induced by far-field plate reorganization is evaluated. © 2018 China University of Geosciences (Beijing) and Peking University
Sequential submergence and drought induce yield loss in rice by affecting redox homeostasis and source-to-sink sugar transport
(Elsevier B.V., 2024) Santosh Kumar; Sahana Basu; A.K. Choudhary; Shashi Shekhar; J.S. Mishra; Sanjeev Kumar; Kumari Shubha; Rachana Dubey; Surajit Mondal; S.K. Dwivedi; N. Bhakta; Rakesh Kumar; Sujoy Sarkar; Srustidhar Dhamudia; Sunny Kumari; Anup Das; Arvind Kumar; Gautam Kumar
Rice cultivation in the rainfed ecosystems of the eastern Indo-Gangetic plain (EIGP) frequently comes across abrupt alternation of submergence and drought during the vegetative and reproductive stages, respectively, within one growing season, and this may be exaggerated with climate change. Therefore, development of combined submergence and drought tolerant rice genotypes might be a timely effort to meet the growing food demand. However, till date no study has been executed on the combination of submergence and drought stress in the field conditions of the EIGP. The present study elucidated the performance of near isogenic lines (NILs) of rice developed for the EIGP through marker assisted pyramiding of quantitative trait loci (QTL) associated with submergence (Sub1) and drought (qDTY1.1 + qDTY2.1 + qDTY3.1) in the background of the popular, high yielding Indo-Gangetic rice variety Swarna. This study included the screening of sixteen rice NILs along with the check varieties Swarna and Swarna Sub1 under cumulative submergence and drought for four consecutive rice growing years (2019–2022). Individual submergence or drought or cumulative stress caused 76, 47, and 85% respective loss in average productivity compared to that of the control conditions. However, rice NILs IR96321–558–563-B-2–1–1, IR96321–315–323-B-3–1–3, IR96321–315–294-B-1–1–1–1, and IR96321–558–209-B-6–1–1 showed outstanding cumulative stress tolerance with sustainable photosynthetic performance and membrane stability. Furthermore, these rice NILs exhibited effective reactive oxygen species scavenging mediated by enhanced antioxidant enzyme activities in source (flag-leaf) and sink (anther) tissues that contributed to conserving the source-to-sink mobilization, leading to improved pollen viability and spikelet fertility under sequential stress conditions. The study identified combined submergence-drought tolerant rice NILs along with an optimum yield level to support global food security and also represented a model crop system to establish mechanisms of multi-stress tolerance in plants. © 2024 Elsevier B.V.
Toxicity and recovery studies of two ayurvedic preparations of iron
(2009) P.K. Sarkar; P.K. Prajapati; V.J. Shukla; B. Ravishankar; A.K. Choudhary
Lauha Bhasma and Mandura Bhasma in 55 mg/kg dose (5 times the therapeutic effective dose) for 60 days exhibited no serious toxic effects in Charles Foster albino rats. Both the drugs showed significant recovery from chronic toxic effect after 45 days of recovery period.
Toxicity studies of bhasmas of makshika and makshika satva
(Indian Drug Manufacturers' Association, 1997) A.K. Choudhary; S.K. Dixit; M. Kumar
In Ayurveda, Bhasmas of Makshika and Makshika Satva finds a very wide application with combination of some other metallic and vegetable products. The present study includes the experiments on mice and rats to explore the possible untoward effect (toxicity) of Bhasmas of Makshika and Makshika Satva at the level of acute, sub-acute and Chronic stages. No, untoward or damaging effects on vital organs of test animals have been found.