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Protein extract of kenaf seed exhibits anticoagulant,antiplatelet and antioxidant activities
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作者 Sujatha M.Hanumegowda Chandramma Srinivasa +6 位作者 Ashwini Shivaiah Manjula M.Venkatappa Ramesha Hanumanthappa Rajesh Rangappa Ramesh K.Laxmaiah Sathisha J.Gonchigar Devaraja Sannaningaiah 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2022年第2期47-58,共12页
Objective:To explore the anticoagulant,antiplatelet and antioxidant activities of protein extract of kenaf seed(PEKS).Methods:Sodium dodecyl sulphate polyacrylamide gel electrophoresis and reverse-phase high-performan... Objective:To explore the anticoagulant,antiplatelet and antioxidant activities of protein extract of kenaf seed(PEKS).Methods:Sodium dodecyl sulphate polyacrylamide gel electrophoresis and reverse-phase high-performance liquid chromatography techniques were employed for protein characterization.Antioxidant activity of PEKS was assessed using 1,1-diphenyl-2-picrylhydrazyl(DPPH)assay.The protective effect of PEKS on sodium nitrite(NaNO2)induced oxidative stress was evaluated using the in vitro red blood cell model,while the effect of PEKS on diclofenacinduced oxidative stress was examined in vivo in rats.Platelet-rich plasma and platelet-poor plasma were used for anticoagulant and antiplatelet activities of PEKS.Results:PEKS revealed similar protein bands on SDS-PAGE under reduced and non-reduced conditions.Several acidic proteins were present in native PAGE.PEKS showed antioxidant properties by scavenging DPPH with an IC50 of 24.58μg.PEKS exhibited a protective effect on NaNO2 induced oxidative stress in red blood cells by restoring the activity of stress markers.In addition,PEKS alleviated diclofenac-induced tissue damage of the liver,kidney,and small intestine.PEKS showed an anticoagulant effect in both in vivo and in vitro experiments by enhancing normal clotting time.PEKS did not affect prothrombin time but increase activated partial thromboplastin time.Furthermore,PEKS inhibited adenosine diphosphate and epinephrine-induced platelet aggregation.Conclusions:PEKS protects tissues from oxidative stress and exhibits antithrombotic activity. 展开更多
关键词 Protein Extract Kenaf seed Oxidative stress ANTIOXIDANT ANTICOAGULANT ANTIPLATELET
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[1-(4-Nitrobenzyl)-2-butyl-4-chloro-1<i>H</i>-imidazol-5-yl]-4, 5-dihydro-1-phenyl-1<i>H</i>-pyrazole: Synthesis, Anti-Inflammatory and Analgesic Activities
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作者 S. Sreenivasa B. J. Shankar 《Open Journal of Medicinal Chemistry》 2013年第2期50-54,共5页
In the present investigation, series of Bis (heterocycle)s bearing pyrazoline in combination of the imidazole derivatives have been synthesized via 1,3-dipolar cycloaddition reactions of N-(nitrobenzyl)-imidazole nitr... In the present investigation, series of Bis (heterocycle)s bearing pyrazoline in combination of the imidazole derivatives have been synthesized via 1,3-dipolar cycloaddition reactions of N-(nitrobenzyl)-imidazole nitrile imines with different dipolarophiles. All the newly synthesized compounds were characterized and screened for analgesic-anti-inflammatory activities and were compared with the standard drugs. The compounds exhibited excellent anti-inflammatory and analgesic activities. Out of the compounds studied 4b, 4d and 4g compounds shown statistically significant activity comparable to the standard drugs Ibuprofen and Aspirin at the same dose. 展开更多
关键词 ANTI-INFLAMMATORY ANALGESIC N-(nitrobenzyl)-imidazole aldehyde CHLORAMINE-T
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Speciation and Geochemical Behaviour of Heavy Metals in Industrial Area Soil of Mysore City, India
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作者 Doddaiah Shivakumar Shivanna Srikantaswamy +1 位作者 Swamy Sreenivasa Budiguppe M. Kiran 《Journal of Environmental Protection》 2012年第10期1384-1392,共9页
Soil is a major reservoir for contaminants as it possesses an ability to bind various chemicals. These chemicals can exist in various forms in soil and different forces keep them bound to soil particles. It is essenti... Soil is a major reservoir for contaminants as it possesses an ability to bind various chemicals. These chemicals can exist in various forms in soil and different forces keep them bound to soil particles. It is essential to study these interactions because the toxicity of chemicals may strongly depend on the form in which they exist in the environment. Another thing is that soil variability and some environmental properties may change in soil and cause leaching of trace toxic elements like heavy metals tightly bound to soil particles. Metals associated with urban soil are of environmental concern because of their direct and indirect effects on human health. The main purposes of this study undertaken in the Mysore city industrial zone were to identify heavy metals with dangerous environmental load and to find out of their environmental impact (Fe, Cr, Cu, Zn, and Ni). The purpose of this work was to provide information on heavy metals concentration in industrial zone soil of Mysore city, India. Soil samples were analyzed for pH, organic matter, and electrical conductivity. Total and available heavy metal concentrations were determined by AAS. In the present study, heavy metal speciation in soil sample carried out were shows that all metals were mainly associated with the oxidizable and residual fraction, which allows us to predict their mobility in the soil sample. 展开更多
关键词 SOIL SPECIATION of HEAVY Metals SEQUENTIAL Extraction
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Crystal and Molecular Structure Analysis in Knoevenagel Condensation Product of Substituted Napthofuran-2-Carbaldehydes
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作者 Avantika Hasija V. Prakash +3 位作者 M. Shet Prakash Vasu G. Krishnasamy Deepak Chopra 《Crystal Structure Theory and Applications》 2020年第3期49-62,共14页
In the current study, two novel Knoevenagel condensation products of substituted napthofuran-2-carbaldehydes were designed, synthesized and characterized. In order to study the intermolecular interactions of titl... In the current study, two novel Knoevenagel condensation products of substituted napthofuran-2-carbaldehydes were designed, synthesized and characterized. In order to study the intermolecular interactions of title compounds, single crystals were grown by slow evaporation solution growth technique at </span><span style="font-family:Verdana;">r</span><span style="font-family:Verdana;">oom temperature and crystal structure has been determined by single crystal X-ray diffraction technique. Both the molecule</span><span style="font-family:Verdana;">s</span><span style="font-family:""><span style="font-family:Verdana;"> crystallize in the monoclinic centrosymmetric space group </span><i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;">2</span><sub><span style="font-size:12px;font-family:Verdana;">1</span></sub><span style="font-family:Verdana;">/</span><i><span style="font-family:Verdana;">c</span></i><span style="font-family:Verdana;"> with one molecule in the asymmetric unit. In compound </span><b><span style="font-family:Verdana;">[4] </span></b><span style="font-family:Verdana;">the molecules are connected via bifurcated C-H···O=C and C-H···N=C</span></span><span style="font-family:Verdana;"> </span><span style="font-family:""><span style="font-family:Verdana;">H-bonds and van der Waals interactions forming a layered structure, whereas in compound </span><b><span style="font-family:Verdana;">[5a</span></b></span><span style="font-family:Verdana;"><b>]</b></span><span style="font-family:""><span style="font-family:Verdana;"> the molecular conformation is stabilized via intramolecular C-H···O H-bond and molecule interacts with other molecule generated via 2</span><sub><span style="font-size:12px;font-family:Verdana;">1</span></sub><span style="font-family:Verdana;">-screw </span><i><span style="font-family:Verdana;">via</span></i><span style="font-family:Verdana;"> bifurcated C-H···O=</span></span><span style="font-family:Verdana;">C along with C-H···N=C H-bonds, which are interacting with nitro- of ot</span><span style="font-family:Verdana;">her molecule generated via same symmetry operation, forming bifurcated C-H···O-N </span><span style="font-family:Verdana;">H-bonds, which helps in formation of molecular sheet-like structure.</span><span style="font-family:Verdana;">Further, in order to understand the various type</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> and nature of intermolecular interactions</span><span style="font-family:Verdana;"> in the supramolecular structure Hirshfeld</span><span style="font-family:Verdana;"> surface analysis</span><span style="font-family:Verdana;"> and fingerprint plot analysis was carried out. 展开更多
关键词 Napthofuran-2-Carbaldehyde 8-Nitro Napthafura-2-Carbaldehyde Knoevenagel Condensation Single Crystal and Hirshfeld Surface Analysis
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Exploring one material for dual applications:A red-emitting Mg_(2)GeO_(4):Eu^(3+)nanophosphor for future generation energy efficient WLEDs and dosimetric applications
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作者 Akshay Arjun G.P.Darshan +3 位作者 S.C.Sharma H.Nagabhushana D.V.Sunitha H.B.Premkumar 《Journal of Rare Earths》 SCIE EI CAS CSCD 2024年第10期1835-1845,共11页
The envisaged design and developme nt of individual mate rials to excavate a broader spectrum of desired properties and offer multiple applications are highly necessitating.Keeping this in mind,a series of forsterite-... The envisaged design and developme nt of individual mate rials to excavate a broader spectrum of desired properties and offer multiple applications are highly necessitating.Keeping this in mind,a series of forsterite-structured Mg_(2)GeO_(4):Eu^(3+)(1 mol%-9 mol%)nanophosphors was synthesized via a solution combustion method using oxalyl dihydrazide as a fuel.The X-ray diffraction patterns confirm the orthorhombic crystal system with a Puma space group.Morphological results clearly show irregularly shaped cluster-like structures with aggregation of the particles.Employing diffuse reflectance spectra,the optical energy band gap of the Mg_(2)GeO_(4):Eu^(3+)(1 mol%-9 mol%)nanophosphors was estimated and obtained to be~4.12-4.32 eV.The photoluminescence emission spectra exhibit intense peaks at^(5)79,589,610,661,and 707 nm,which are due to characteristic^(5)D_(0)→^(7)F_(0),^(5)D_(0)→^(7)F_(1),^(5)Do→^(7)F_(2),^(5)D_(0)→^(7)F_(3)and^(5)D_(0)→^(7)F_(4)transitions of Eu^(3+)ions,respectively.The Commission International de L'Eclairage color coordinates are gradually tuned from pale red(0.5980,0.4012)to a pure red(0.6385,0.3611)region.Thermoluminescence glow peaks showcase excellent super-linear response at low doses ofγ-irradiations,indicating that the prepared phosphor can be used in thermoluminescent personal dosimetry which is a biological tissue equivalent.The aforementioned results demonstrate that the prepared Mg_(2)GeO_(4):Eu^(3+)(1 mol%-9 mol%)nanophosphors are considered an excellent candidate for dual applications,i.e.,red component in future generation white-light-emitting diodes(WLEDs)and personal dosimetric applications. 展开更多
关键词 NANOPHOSPHORS Photoluminescence THERMOLUMINESCENCE DOSIMETRY Photometric properties Rare earths
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Comparative study of Eu^(3+)-activated LnOCl(Ln=La and Gd) phosphors and their Judd-Ofelt analysis 被引量:4
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作者 N.Dhananjaya C.Shivakumara +2 位作者 Rohit Saraf Sukanti Behera H.Nagabhushana 《Journal of Rare Earths》 SCIE EI CAS CSCD 2015年第9期946-953,共8页
Eu3+-activated layered LnOCI (Ln=La and Gd) phosphors were synthesized by the conventional solid-state method at relatively low temperature (700 ℃) and shorter duration of 2 h. The structural parameters were ref... Eu3+-activated layered LnOCI (Ln=La and Gd) phosphors were synthesized by the conventional solid-state method at relatively low temperature (700 ℃) and shorter duration of 2 h. The structural parameters were refined by the Rietveld refinement analysis and confirmed by the high resolution transmission electron microscopy (HRTEM). Both the compounds were crystallized in the tetragonal structure with space group P4/nmm (No. 129). The homogeneity of the elements were ana- lyzed by TEM mapping and found to be uniformly distributed. The photoluminescence spectra revealed that the intensity of 5D0--7F2 transition (619 nm) was more intense in Eu3+-activated GdOC1 compared to LaOC1. This was due to the property of Gd3+ ions to act as an intermediate sublattice to facilitate the energy transfer to Eu3+ ions. Intensity parameters and radiative properties such as transition probabilities, radiative lifetime and branching ratio were calculated using the Judd-Ofelt theory. The CIE color coordinates result revealed that the Eu3+-activated GdOC1 (0.641, 0.354) phosphor was close to the commercial red phosphors like, Y203:Eu3+ (0.645, 0.347), Y202S:Eu3+ (0.647, 0.343) and National Television System Committee (NTSC) (0.67, 0.33). The results suggest that the present GdOCI:Eu3+ compound acts as a potential candidate for red phosphor materials. 展开更多
关键词 LaOC1 GdOC1 PHOSPHORS Judd-Ofelt CIE rare earths
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Rapid visualization of latent fingerprints using novel CaSiO_3:Sm^(3+) nanophosphors fabricated via ultrasound route 被引量:4
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作者 R.B.Basavaraj G.P.Darshan +2 位作者 B.Daruka Prasad S.C.Sharma H.Nagabhushana 《Journal of Rare Earths》 SCIE EI CAS CSCD 2019年第1期32-44,M0003,共14页
Latent fingerprints (LFPs) were the most significant identification method for individualization. Most commonly available fingerprints (FPs) in crime spot investigation were latent and patent types. Generally,LFPs wer... Latent fingerprints (LFPs) were the most significant identification method for individualization. Most commonly available fingerprints (FPs) in crime spot investigation were latent and patent types. Generally,LFPs were invisible and thus the effective visualization technique necessitates for the analysis of such FPs. In the past years, many traditional visualization techniques have been employed, but suffered with low resolution, sensitivity, contrast and high background noise. To overcome such limitations, we synthesized Sm^(3+) doped CaSiO_3 nanophosphors (NPs) via an ultrasound irradiation route using mimosa pudica (m. p.)leaves extract as a bio-surfactant. The morphological behavior of the prepared samples was extensively studied by varying the concentration of the m. p. extract, ultrasound irradiation duration, pH level of the precursor solution and sonication power. The photoluminescence (PL) emission spectra exhibit characteristic peaks at~561,601 and 647 nm, which were attributed to^5G_(5/2)→~6H_J(J=5/2,7/2 and 9/2) transitions of Sm^(3+) ions.The Judd-Ofelt(J-O) intensity parameters and other radiative properties were estimated using PL data. The Commission International de I'Eclairage (CIE) color coordinates were positioned in orange-red region shows average correlated color temperature (CCT) value of~3576 K. The optimized samples can be used as a labeling agent for the visualization of LFPs on various porous and non-porous surfaces under normal light irradiation. The visualized FPs reveals well defined ridge characteristics, namely whorl, loop,arch, bifurcation, eye, island, bridge, sweat pores, etc, with high sensitivity, selectivity, low contrast and background hindrance. Aforementioned results evidence that the prepared CaSiO_3:Sm^(3+) NPs were promising luminescent materials for solid state lighting and forensic applications. 展开更多
关键词 Ultrasonication synthesis Photoluminescence FINGERPRINT PHOTOMETRIC properties Judd-Ofelt analysis RARE earths
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Rational design of monovalent ions (Li,Na,K) co-doped ZnAl2O4:Eu3+ nanocrystals enabling versatile robust latent fingerprint visualization 被引量:3
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作者 F.Femila Komahal H.Nagabhushana +4 位作者 R.B.Basavaraj G.P.Darshan Hajeebaba K.Inamdar S.C.Sharma B.Daruka Prasad 《Journal of Rare Earths》 SCIE EI CAS CSCD 2019年第7期699-705,共7页
Alkali metal ions(M+ = Na+,Li+,K+) co-doped ZnAl2O4:Eu3+(5 mol%)(ZAE) nanopowders(NPs) were prepared via solution combustion route using Mimosa pudica(MP) leaves extract as a fuel. PXRD results of co-doped samples enh... Alkali metal ions(M+ = Na+,Li+,K+) co-doped ZnAl2O4:Eu3+(5 mol%)(ZAE) nanopowders(NPs) were prepared via solution combustion route using Mimosa pudica(MP) leaves extract as a fuel. PXRD results of co-doped samples enhance the crystallinity and grain growth. Photoluminescence(PL) of the prepared ZAE and ZAE:M+(M+ = Na+, Li+, K+) NPs shows intense emission peaks in the range of 550-750 nm and ascribed to 5D0→7FJ(J=0-4) transitions of Eu3+ ions, respectively. A 2-fold enhancement in PL intensity was observed in Li+ co-doped samples. The optimized ZnAl2O4:Eu3+(5 mol%), Li+(1 wt%)(ZAEL)NPs were used to visualize LFPs on various porous, semi-porous and non-porous surfaces through robust powder dusting technique. The visualized latent fingerprints(LFPs) reveal well defined level 1-3 ridge characteristics under several tests such as fingerprint aging and fresh water treatment for various time durations. The obtained results clearly evidence that the prepared NPs are quite useful for multifunctional applications such as advanced forensic and solid state lightning. 展开更多
关键词 Photoluminescence LATENT FINGERPRINTS Solid state lightning Alkali metal IONS Rare earths
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Enhancement of luminescence intensity and spectroscopic analysis of Eu^(3+) activated and Li^+ charge-compensated Bi_2O_3 nanophosphors for solid-state lighting 被引量:1
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作者 S.Ashwini S.C.Prashantha +1 位作者 RamachANDra Naik H.Nagabhushana 《Journal of Rare Earths》 SCIE EI CAS CSCD 2019年第4期356-364,共9页
The present work reports the synthesis, characterization, photoluminescence and photocatalytic activity of Eu^(3+)(1 mol%-11 mol%) doped and Li^+(0.5 mol%-5 mol%) co-doped Bi_2 O_3 nanophosphors(NPs) by sonochemical m... The present work reports the synthesis, characterization, photoluminescence and photocatalytic activity of Eu^(3+)(1 mol%-11 mol%) doped and Li^+(0.5 mol%-5 mol%) co-doped Bi_2 O_3 nanophosphors(NPs) by sonochemical method. The average particle size was estimated using powder X-ray diffraction(PXRD)and transmission electron microscopy(TEM) and is found to be in the range of 30-35 nm. The scanning electron microscopy(SEM) images were highly dependent on sonication time and concentration of epigallocatechin gallate(EGCG) bio-surfactant. The energy gap of doped and co-doped Bi_2 O_3 nanophosphors was estimated using Kubelka-Munk(K-M) function and is found to be in the range of2.9-3.08 eV. The effect of Li+ co-doping on luminescence of optimized Bi_2 O_3:Eu^(3+) was studied and is found about more than 3 fold enhancement of emission intensity. Judd-Ofelt parameters(Ω_2, Ω_4 and Ω_6).transition probabilities(A_T), quantum efficiency(η), luminescence lifetime(τ_(rad)), color chromaticity coordinates(CIE) and correlated color temperature(CCT) values were estimated from the emission spectra and are discussed in detail. The estimated CIE chromaticity co-ordinates are very close to the NTSC(National Television Standard Committee) standard value of red emission. The synthesized NPs show excellent photocatalytic activity of acid red-88 under UV-light irradiation, which can degrade 98.1% in60 min. The decreasing electron-hole pair recombination rate with quick electron transfer ability is predominantly ascribed to the balance between crystallite size, morphology, band gap, defects, surface area, etc. These results show a light for the use of sonochemical route of Bi_2 O_3:Eu^(3+):Li^+ in solid state display and photocatalytic applications. 展开更多
关键词 Bi2O3:Eu3+:Li+ SONOCHEMICAL Photoluminescence CIE n CCT Photocatalysis Rare earths
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Effect of laminate thickness on moisture diffusion of polymer matrix composites in artificial seawater ageing 被引量:2
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作者 Ratna PAL H.N.NARASIMHA MURTHY +2 位作者 M.SREEJlTHz,K.R.VISHNU MAHESH M.KRISHNA IS.C.SHARMA 《Frontiers of Materials Science》 SCIE CSCD 2012年第3期225-235,共11页
The influence of laminate thickness of polymer matrix composites on moisture diffusion in seawater immersion, as well as the resulting mechanical property degradation for composites of glass/isopolyester (G/IPE), ca... The influence of laminate thickness of polymer matrix composites on moisture diffusion in seawater immersion, as well as the resulting mechanical property degradation for composites of glass/isopolyester (G/IPE), carbon/isopolyester (C/IPE), glass/vinylester (G/VE) and carbon/vinylester (CNE), was investigated in this paper. Laminates 3 and 10 mm in thickness, fabricated using the wet hand lay-up technique, were characterized for moisture absorption in artificial seawater medium, and their flexural strength and interlaminar shear strength (ILSS) degradations were studied. Moisture diffusion was observed to be anamolous to the Fick's law for both 3 and 10 mm thick samples in the later stage of diffusion. Moisture permeability of 10 mm thick samples was two to three order greater than that of 3 mm thick ones, while the time to moisture saturation remained unchanged. With the increase of laminate thickness, moisture saturation increased by 1.4% for CNE and 7% for GriPE. The residual flexural strength and ILSS were greater in case of 10 mm thick specimens after 200 days of exposure. SEM examination of the fractured specimens showed greater levels of fibre/matrix debonding in 10 mm thick specimens. 展开更多
关键词 polymer matrix composite diffusion coefficient Fick's law DEGRADATION
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Multifunctional Dy(Ⅲ)doped di-calcium silicate array for boosting display and forensic applications 被引量:4
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作者 M.Venkataravanappa R.B.Basavaraj +5 位作者 G.P.Darshan B.Daruka Prasad S.C.Sharma P.Hema Prabha S.Ramani H.Nagabhushana 《Journal of Rare Earths》 SCIE EI CAS CSCD 2018年第7期690-702,共13页
Latent fingerprints(LFPs) are the major physical evidences for the identification of individuals during crime spot investigation. Till date, numerous methods were followed to visualize LFPs. However, simple,accurate... Latent fingerprints(LFPs) are the major physical evidences for the identification of individuals during crime spot investigation. Till date, numerous methods were followed to visualize LFPs. However, simple,accurate, and cost-effective method has wide scope in advanced forensic field. In our work, Ca2 SiO4:Dy^(3+)nanopowders(NPs) were fabricated via solution combustion route. The optimized sample was employed for the visualization of overlapped LFPs by the cost effective powder dusting method. The obtained results reveals the complete three levels of ridge characteristics with high sensitivity, reproducibility,selectivity, and reliability on various complex surfaces. The photoluminescence(PL) spectra consist of intense peaks at ~ 480 and 574 nm owing to ~4 F(9/2) →~6 H(15/2) and ~4 F(9/2)→~6 H(13/2) 4 f transitions of Dy3+ ions,respectively. The photometric properties confirm that the samples exhibit intense white emission with high color purity. Therefore, the prepared NPs could be a definitive choice as an advanced luminescent NPs for forensic, solid state lighting and portable FED devices. 展开更多
关键词 Solution combustion PHOTOLUMINESCENCE Solid state lighting Fingerprint patterns Sweat pores Rare earths
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Mechanical behavior of organo-modified Indian bentonite nanoclay fiber-reinforced plastic nanocomposites 被引量:1
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作者 N. RAGHAVENDRA H. N. NARASIMHA MURTHY +5 位作者 M. KRISHNA K. R. VISHNU MAHESH R. SRIDHAR S. FIRDOSH G. ANGADI S. C. SHARMA 《Frontiers of Materials Science》 SCIE CSCD 2013年第4期396-404,共9页
The aim of the research was to examine the influence of organo-modified Indian bentonite (IB) nanoclay dispersed in vinyisster on the mechanical properties of nanoclaylvinylesterlglass nanocomposRes. Nanoclay was or... The aim of the research was to examine the influence of organo-modified Indian bentonite (IB) nanoclay dispersed in vinyisster on the mechanical properties of nanoclaylvinylesterlglass nanocomposRes. Nanoclay was organically modified using cationic surfactant hexadecyltrimethylammonium bromide (HDTMA-Br) by cation exchange method and dispersed in vinylester using ultrasonication and twin screw extrusion. XRD of nanoclaylvinylester revealed exfoliaUon at 4 wt.% nanoclay indicating uniform dispersion in the polymer. DSC results showed improvement in glass transition temperature by 22.3% in 4 wt.% nanoclaylvinylester/glass when compared with that of vinylester/glass. Nanoclay/vinylester/glass with 4 wt,% nanoclay showed 29.23%, 23.84% and 60.87% improvement in ultimate tensile strength (UTS), fiexural strength (FS) and interlaminar shear strength (ILSS) respectively when compared with those of vinylester! glass. The mode of tensile failure examined by SEM showed no agglomeration of nanoclay in 4 wt.% nanoclayNinylester/glass specimens. 展开更多
关键词 Indian bentonite (IB) ultrasonication twin-screw extrusion mechanical property
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α-Fe_2O_3 nanoparticles:An efficient,inexpensive catalyst for the one-pot preparation of 3,4-dihydropyrano[c]chromenes 被引量:2
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作者 H.Nagabhushana S.Sandeep Saundalkar +5 位作者 L.Muralidhar B.M.Nagabhushana C.R.Girija D.Nagaraja M.A.Pasha V.P.Jayashankara 《Chinese Chemical Letters》 SCIE CAS CSCD 2011年第2期143-146,共4页
This paper describes the combustion synthesis ofα-Fe2O3 nanopowder at much lower temperature and its catalytic activity for the one-pot preparation of 3,4-dihydropyrano[c]chromenes.The combustion derivedα-Fe_2O_3 na... This paper describes the combustion synthesis ofα-Fe2O3 nanopowder at much lower temperature and its catalytic activity for the one-pot preparation of 3,4-dihydropyrano[c]chromenes.The combustion derivedα-Fe_2O_3 nanopowder was characterized by powder X-ray diffraction(PXRD),Braunauer,Emmett and Teller(BET) surface area,scanning electron microscopy(SEM) and Fourier transform infrared spectroscopy(FTIR).Highly efficient,three-component condensation of aromatic aldehyde,malanonitrile and 4- hydroxycoumarin catalyzed byα-Fe2O3 nanoparticles at room temperature is described.The method offers an excellent alternative to the synthesis of 3,4-dihydropyrano[c]chromenes.The reactions are rapid,clean,and the products with good yield and high purity. 展开更多
关键词 α-Fe2O3 nanopowder One pot three-component condensation Aromatic aldehyde Malanonitrile 4-Hydroxycoumarin
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Polytypic transformations of aluminum hydroxide: A mechanistic investigation 被引量:1
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作者 Thimmasandra Narayan Ramesh 《Particuology》 SCIE EI CAS CSCD 2012年第3期359-364,共6页
The diffusion of ammonia vapors into a solution of aluminum nitrate or ferric nitrate results in the precipitation of their respective hydroxides and oxyhydroxides. Polymorphic phase formation of aluminum hydroxide is... The diffusion of ammonia vapors into a solution of aluminum nitrate or ferric nitrate results in the precipitation of their respective hydroxides and oxyhydroxides. Polymorphic phase formation of aluminum hydroxide is controlled by the rate of crystallization. The PXRD patterns of products obtained via vapor phase diffusion revealed that poorly ordered aluminum hydroxide is formed during the initial stages of crystallization. After 8 days, the formation of the bayerite phase of aluminum hydroxide was observed. Upon prolonged exposure to ammonia vapors, bayerite was transformed into gibbsite. The infrared spectrum of the product confirmed the presence of different polytypic phases of aluminum hydroxide. The results demonstrated that the crystal structure of metal hydroxides is controlled by the rate of crystallization, nature of the metal ion, site selectivity and specificity and preparative conditions. 展开更多
关键词 Vapor phase diffusionAluminum hydroxideGibbsiteBayeritePolytypism
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Rauvolfia serpentina-Mediated Green Synthesis of CuO Nanoparticles and Its Multidisciplinary Studies
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作者 K.Lingaraju H.Raja Naika +3 位作者 K.Manjunath G.Nagaraju D.Suresh H.Nagabhushana 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2015年第9期1134-1140,共7页
Copper oxide nanoparticles (CuO Nps) were successfully synthesized by solution combustion method using aqueous leaf extract of Rauvolfia serpentina as a fuel. The structure and morphology of the CuO nanoparticles (... Copper oxide nanoparticles (CuO Nps) were successfully synthesized by solution combustion method using aqueous leaf extract of Rauvolfia serpentina as a fuel. The structure and morphology of the CuO nanoparticles (Nps) were characterized by powder X-ray diffraction (PXRD), UV-visible spectroscopy (UV-visible), scanning electron microscopy (SEM), transmission electron microscopy (TEM), etc. The PXRD patterns reveal the formation of monoclinic phase with crystallite structure. SEM images indicate that the particles have sponge-like structure being highly porous and agglom- erated with large surface area. The average crystallite sizes were found to be in the range of 10-20 nm by Scherrer's method. The CuO Nps size was further confirmed by TEM. Further, CuO Nps exhibit good photocatalytic activity for the photodegradation of trypan blue dye, indicating that it acts as a promising semiconducting material. The antibacterial properties of CuO nanoparticles were investigated against pathogenic bacterial strains, namely Gram -ve Escherichia coli (NCIM-5051) and Pseudomonas desmolyticum (NCIM-2028) and Gram +ve bacteria Staphylococcus aureus (NCIM- 5022) using the agar well diffusion method. 展开更多
关键词 CUO NANOPARTICLES Rauvolfia serpentina Photocatalytic activity Antibacterial activity
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Mechanical, thermal and fire nanoclay/vinylester retardation behaviours of nanocomposites
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作者 K. R. VISHNU MAHESH H. N. NARASIMHA MURTHY +5 位作者 B. E. KUMARA SWAMY S. C. SHARMA R. SRIDHAR Niranjan PATTAR M. KRISHNA B. S. SHERIGARA 《Frontiers of Materials Science》 SCIE CSCD 2011年第4期401-411,共11页
The dispersion of montmorillonite (MMT) in vinylester for preparing nanoclay/vinylester gel coat was reported. Two sets of MMT/vinylester specimens, namely Type I and Type 2, were prepared for comparative studies. T... The dispersion of montmorillonite (MMT) in vinylester for preparing nanoclay/vinylester gel coat was reported. Two sets of MMT/vinylester specimens, namely Type I and Type 2, were prepared for comparative studies. Type I specimens were prepared using ultrasonication only, and Type 2 specimens were prepared using both ultrasonication and twin-screw extrusion. According to XRD and TEM results, Type 2 specimens showed lower levels of nanoclay agglomeration and higher levels o! exfoliation. DSC results showed that the glass transition temperatures of Type 2 specimens are higher than those of Type 1 specimens. TGA results showed that the residual weight of 4 wt.% MMT/vinylester of Type 1 was 7.38%, while the corresponding value of Type 2 was 13,5%, indicating lower thermal degradation in the latter. MMTt vinylester/glass and MMT/vinylester/carbon specimens were fabricated and tested for mechanical and fire retardation behaviours. Type 2 based nanocomposite laminates showed greater values of ultimate tensile strength, flexural strength, interlaminar shear strength, impact strength, horizontal burning rate, and vertical burning rate than Type 1 based laminates. SEM images of tensile fractured surfaces revealed that Type 2 based laminates have no or less agglomeration of nanoclay than Type 1 based laminates. 展开更多
关键词 twin-screw extrusion MONTMORILLONITE NANOCLAY NANOCOMPOSITE vinylester
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