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Amar A. Telke,Avinash A. Kadam,Sujit S. Jagtap,Jyoti P. Jadhav,Sanjay P. Govindwar 한국생물공학회 2010 Biotechnology and Bioprocess Engineering Vol.15 No.4
In our study, we produced intracellular blue laccase by growing the filamentous fungus Aspergillus ochraceus NCIM-1146 in potato dextrose broth. The enzyme was then purified 22-fold to a specific activity of 4.81 U/mg using anion-exchange and size exclusion chromatography. The molecular weight of purified laccase was estimated as 68 kDa using sodium dodecyl sulfate polyacrylamide gel electrophoresis. The enzyme showed maximum substrate specificity toward 2,2'-Azinobis, 3-ethylbenzothiazoline-6-sulfonic acid than any other substrate. The optimum pH and temperature for laccase activity were 4.0 and 60ºC, respectively. The purified enzyme was stable up to 50ºC, and high laccase activity was maintained at pH 5.0 ~ 7.0. Laccase activity was strongly inhibited by sodium azide, EDTA, dithiothreitol, and L-cysteine. Purified laccase decolorized various textile dyes within 4 h in the absence of redox mediators. HPLC and FTIR analysis confirmed degradation of methyl orange. The metabolite formed after decolorization of methyl orange was characterized as p-N,N'-dimethylamine phenyldiazine using GCMS.
Organocatalytic Enantioselective Cycloetherifications Using a Cooperative Cation-Binding Catalyst
Jadhav, Amol P.,Oh, Jeong-A,Hwang, In-Soo,Yan, Hailong,Song, Choong Eui American Chemical Society 2018 ORGANIC LETTERS Vol.20 No.17
<P>A highly enantioselective cycloetherification strategy for the straightforward synthesis of enantioenriched tetrahydrofurans, tetrahydropyrans, and oxepanes using Song’s cation-binding oligoEG catalyst and KF as the base is demonstrated. A wide range of <I>ε-</I>, <I>ζ-</I>, and η-hydroxy-α,β-unsaturated ketones were cyclized to the corresponding five-, six-, and seven-membered chiral oxacycles with high enantiopurity. This remarkably successful catalysis can be ascribed to systematic cooperative cation-binding catalysis in a densely confined supramolecular chiral cage generated <I>in situ</I> from the chiral catalyst, substrate, and KF.</P> [FIG OMISSION]</BR>
Kale, Sayali B.,Kalubarme, Ramchandra S.,Mahadadalkar, Manjiri A.,Jadhav, Harsharaj S.,Bhirud, Ashwini P.,Ambekar, Jalinder D.,Park, Chan-Jin,Kale, Bharat B. The Royal Society of Chemistry 2015 Physical Chemistry Chemical Physics Vol.17 No.47
<P>Hierarchical 3D ZnIn2S4/graphene (ZnIn2S4/Gr) nano-heterostructures were successfully synthesized using an in-situ hydrothermal method. The dual functionality of these nano-heterostructures i.e. for solar hydrogen production and lithium ion batteries has been demonstrated for the first time. The ZnIn2S4/Gr nano-heterostructures were optimized by varying the concentrations of graphene for utmost hydrogen production. An inspection of the structure shows the existence of layered hexagonal ZnIn2S4 wrapped in graphene. The reduction of graphene oxide (GO) to graphene was confirmed by Raman and XPS analyses. The morphological analysis demonstrated that ultrathin ZnIn2S4 nanopetals are dispersed on graphene sheets. The optical study reveals the extended absorption edge to the visible region due to the presence of graphene and hence is used as a photocatalyst to transform H2S into eco-friendly hydrogen using solar light. The ZnIn2S4/Gr nano-heterostructure that is comprised of graphene and ZnIn2S4 in a weight ratio of 1 : 99 exhibits enhanced photocatalytically stable hydrogen production i.e. B6365 mmole h(-1) under visible light irradiation using just 0.2 g of nano-heterostructure, which is much higher as compared to bare hierarchical 3D ZnIn2(S4). The heightened photocatalytic activity is attributed to the enhanced charge carrier separation due to graphene which acts as an excellent electron collector and transporter. Furthermore, the usage of nano-heterostructures and pristine ZnIn2S4 as anodes in lithium ion batteries confers the charge capacities of 590 and 320 mA h g(-1) after 220 cycles as compared to their initial reversible capacities of 645 and 523 mA h g(-1), respectively. These nano-heterostructures show high reversible capacity, excellent cycling stability, and high-rate capability indicating their potential as promising anode materials for LIBs. The excellent performance is due to the nanostructuring of ZnIn2S4 and the presence of a graphene layer, which works as a channel for the supply of electrons during the charge-discharge process. More significantly, their dual functionality in energy generation and storage is quite unique and commendable.</P>
Jadhav, A.P.,Thi Dinh, T.D.,Khan, S.,Lee, S.Y.,Park, J.K.,Park, S.W.,Oh, J.H.,Moon, B.K.,Jang, K.,Yi, S.S.,Kim, J.H.,Cho, S.H.,Jeong, J.H. Pergamon Press 2016 Materials research bulletin Vol.83 No.-
Precipitation and re-precipitation of metal ions has been carried out from original and supernatant solution producing Bi<SUP>3+</SUP> - Eu<SUP>3+</SUP> doped Y<SUB>2</SUB>O<SUB>3</SUB>:Eu<SUP>3+</SUP> and Eu<SUP>3+</SUP>/Tb<SUP>3+</SUP> doped Y<SUB>2</SUB>O<SUB>3</SUB>, respectively. Shorter reaction time is unable to consume all metal ions present in the solution which can be utilized through re-precipitation process. The doping of Bi<SUP>3+</SUP> - Eu<SUP>3+</SUP> in Y<SUB>2</SUB>O<SUB>3</SUB> helps to absorb maximum UV light. The activation of Y<SUB>2</SUB>O<SUB>3</SUB> matrix by Bi<SUP>3+</SUP> and Eu<SUP>3+</SUP> ions, together and separately, were studied considering the excitation energy transfer to the luminescence centers. The successful replacement of Y<SUP>3+</SUP> by RE<SUP>3+</SUP> ions can help for fine tuning of emission wavelength. Re-precipitation of supernatant solution by adding terbium precursor can successively produce uniform sized Tb<SUP>3+</SUP> doped Y<SUB>2</SUB>O<SUB>3</SUB>:Eu<SUP>3+</SUP>. The re-precipitation of the supernatant solution ensures maximum consumption of metal ions for higher product yield and possible fine tuning of emission wavelengths.
Jadhav, A.P.,Oh, J.H.,Park, S.W.,Choi, H.,Moon, B.K.,Choi, B.C.,Jang, K.,Jeong, J.H.,Yi, S.S.,Kim, J.H. Elsevier 2016 Current Applied Physics Vol.16 No.10
<P>A phosphor with higher emission efficiency in the visible region can be very helpful in various optoelectronics applications such as solar cells. Effective conversion of UV and NIR radiations to more useful visible and red emissions were carried out through Gd2O3:Er3+ nanostructures synthesized by conventional co-precipitation method. The spectroscopic study of Gd2O3: Er3+ samples were carried out as a function of dopant concentration under the excitation wavelengths of 378, 975 and 1540 nm, respectively. The doping of erbium show downconversion emission at 561 and 660 nm under 378 nm excitation while upconversion emission under 975 and 1540 nm excitations shows upconversion of NIR photons to 561 and 660 nm visible emissions. The enhanced red emission (660 nm) at higher erbium concentration was observed due to the dominant cross-relaxation processes. The efficiency of upconversion luminescence is highly dependent on the various relaxation and energy transfer processes involved in different energy levels of erbium. The intensity of downconversion and upconversion emission was enhanced by lithium co-doping in Gd2O3: Er3+ nanostructures. The incorporation of alkali metal ions in Gd2O3: Er3+ shows considerable enhancement in downconversion and upconversion emission intensity making the phosphor more suitable for optoelectronic applications. (C) 2016 Elsevier B.V. All rights reserved.</P>
Red emitting Y2O3:Eu3+ nanophosphors with >80% down conversion efficiency
Jadhav, A. P.,Pawar, A. U.,Pal, U.,Kang, Y. S. Royal Society of Chemistry 2014 Journal of Materials Chemistry C Vol.2 No.3
Obtaining nanophosphors of a controlled size and shape with a high quantum efficiency is the current challenge for display and imaging technologies. Although the surface state induced luminescence quenching in nanophosphors may be compensated to some extent by incorporating activators like rare-earth ions, or by exploiting their quantum size effect, obtaining nanophosphors with quantum efficiencies as high as their bulk counterparts remains elusive. In the present article, we report on the synthesis of uniform Eu-doped Y2O3 nanoparticles, with an average size of 20-53 nm and a down conversion efficiency as high as 85%, using a simple chemical precipitation technique. Along with size control, the effects of Eu3+ content on their emission behaviors have been discussed. We believe the low-cost synthesis process of these nanoparticles will greatly enhance their application potential in optical display and bio-imaging technologies.
Dhawal P. Tamboli,Amar A. Telke,Vishal V. Dawkar,Shekhar B. Jadhav,Sanjay P. Govindwar 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.4
Aryl alcohol oxidase (AAO) produced by dye decolorizing bacteria Sphingobacterium sp. ATM, was purified 22.63 fold to a specific activity of 21.75 μmol/min/mg protein using anion exchange and size exclusion chromatography. The molecular weight of the purified AAO was found to be 71 kDa using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE),and confirmed by zymography of AAO using L-dopa. The enzyme showed substrate specificity towards veratryl alcohol, followed by n-propanol. The optimum pH and temperature of purified AAO were found to be 3.0 and 40°C, respectively. The K_m and V_(max) of AAO was 1.1615mM and 3.13 mM/min when veratryl alcohol was used as substrate. Sodium azide showed maximum inhibition while ethylenediamine tetra acetic acid (EDTA), L-cysteine and dithiothreitol showed slight inhibition. Metal ions also showed slight inhibition. HPLC analysis confirmed the degradation of Direct Red 5B. The metabolite obtained after decolorization of Direct Red 5B was characterized as 3 diazenyl 7 [-(phenyl carbonyl) amino] naphthalene-2-sulfonic acid using GC-MS analysis.
C.E. Patil,N.L. Tarwal,P.R. Jadhav,P.S. Shinde,H.P. Deshmukh,J.D. Song,A.V. Moholkar,M.G. Gang,김진혁,P.S. Patil 한국물리학회 2014 Current Applied Physics Vol.14 No.3
Vanadium pentoxide (V2O5) mixed tungsten trioxide (WO3) thin films have been synthesized by a novel pulsed spray pyrolysis technique (PSPT) on glass and fluorine doped tin oxide (FTO) coated glass substrates at 400 C. Aqueous solutions of equimolar vanadium chloride and ammonium tungstate were mixed in volume proportions (5%, 10% and 15%) for the deposition of V2O5eWO3 thin films. The structural, morphological, optical and electrochemical properties of V2O5eWO3 thin films were investigated by FT-IR, XRD, SEM, cyclic voltammetry, chronoamperometry and chronocoulometry techniques. The results showed that the electrochemical properties of V2O5 were altered by mixing WO3. All the films exhibited cathodic electrochromism in lithium containing electrolyte (0.5 M LiClO4 þ propylene carbonate (PC)). Maximum coloration efficiency (CE) of about 49 cm2 C1 was observed for the V2O5 film mixed with 15% WO3. The electrochemical stability of the sample was examined and it was found to be stable up to 1000 cycles.
Patil, C.E.,Tarwal, N.L.,Jadhav, P.R.,Shinde, P.S.,Deshmukh, H.P.,Karanjkar, M.M.,Moholkar, A.V.,Gang, M.G.,Kim, J.H.,Patil, P.S. Elsevier 2014 Current Applied Physics Vol.14 No.3
Vanadium pentoxide (V<SUB>2</SUB>O<SUB>5</SUB>) mixed tungsten trioxide (WO<SUB>3</SUB>) thin films have been synthesized by a novel pulsed spray pyrolysis technique (PSPT) on glass and fluorine doped tin oxide (FTO) coated glass substrates at 400 <SUP>o</SUP>C. Aqueous solutions of equimolar vanadium chloride and ammonium tungstate were mixed in volume proportions (5%, 10% and 15%) for the deposition of V<SUB>2</SUB>O<SUB>5</SUB>-WO<SUB>3</SUB> thin films. The structural, morphological, optical and electrochemical properties of V<SUB>2</SUB>O<SUB>5</SUB>-WO<SUB>3</SUB> thin films were investigated by FT-IR, XRD, SEM, cyclic voltammetry, chronoamperometry and chronocoulometry techniques. The results showed that the electrochemical properties of V<SUB>2</SUB>O<SUB>5</SUB> were altered by mixing WO<SUB>3</SUB>. All the films exhibited cathodic electrochromism in lithium containing electrolyte (0.5 M LiClO<SUB>4</SUB> + propylene carbonate (PC)). Maximum coloration efficiency (CE) of about 49 cm<SUP>2</SUP> C<SUP>-1</SUP> was observed for the V<SUB>2</SUB>O<SUB>5</SUB> film mixed with 15% WO<SUB>3</SUB>. The electrochemical stability of the sample was examined and it was found to be stable up to 1000 cycles.