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Antifungal Activity of Some Essential Oils against Four Fungi
Yun, Kyeong-Won,N.K. Dubey,Han, Dong-Min,Kil, Bong-Seop 원광대학교기초자연과학연구소 1992 基礎科學硏究誌 Vol.11 No.3
5種 管束植物 즉, Citrus medica, Trachyspermum ammi, Nepeta hindostana, Amomum subulatum과 Hyptis suaveolens로부터 抽出한 정유(精油)를 처리하여 4종 곰팡이에 대한 抗菌力 실험을 실시하였다. 그 결과 C. medica, N. hindostana and T. ammi의 精油가 곰팡이의 생장을 크게 抑制했으며 A. subulatum과 H. suaveolens의 정유는 억제력이 적었다. 植物體로부터 추출한 精油와 合成抗菌劑, 즉 Dithane M-45, Ceresan, Captan과 비교하여 본 결과 본 실험에 사용한 天然化學物質이 더 효과적으로 곰팡이 생장을 抑制했다. Essential oils isolated from five angiospermic plants viz. Citrus medica, Trachyspermum ammi, Nepeta hindostana, Amomum subulatum, and Hyptis suaveolens have been tested against four fungi viz. Aspergillus awamori, Alternaria matini, Aspergillus nidulans and Penicillium sp. at 100ppm, 500ppm, and 1,000ppm. The oils of C. medica, N. hindostana and T. ammi were found to be effective in checking growth of fungi, while the Hyptis and Amomum oils were observed to be the worst effective. The antifungal potency of some of the oils has been compared with synthetic fungicides viz. Dithane M-45, Ceresan and Captan.
Singh, Vijay,Shinde, K.N.,Pathak, M.S.,Singh, N.,Dubey, Vikas,Singh, Pramod K.,Jirimali, H.D. Elsevier 2018 OPTIK -STUTTGART- Vol.164 No.-
<P><B>Abstract</B></P> <P>A series of Tb<SUP>3+</SUP>-doped CaLaAl<SUB>3</SUB>O<SUB>7</SUB> phosphors were successfully synthesized via a sol-gel method. The formation of the synthesized phosphors was confirmed using X-ray powder diffraction (XRPD) studies. A scanning electron microscope (SEM) was used to characterize the surface morphology and to investigate the photoluminescence behaviors in detail. Under the excitation of 235 nm, the emission spectrum consists of the characteristic Tb<SUP>3+</SUP> transitions that mainly peak at 543 nm and correspond to the <SUP>5</SUP>D<SUB>4</SUB> → <SUP>7</SUP>F<SUB>5</SUB> transition. The intensity was greatly improved due to the Tb<SUP>3+</SUP> concentration in the present phosphors. The optimum Tb<SUP>3+</SUP>-doping concentration was determined to be 0.05 mol. The chromaticity coordinates of the CaLaAl<SUB>3</SUB>O<SUB>7</SUB>:Tb<SUP>3+</SUP> were fixed to make it tunable for the blue-to-green region. The typical photographs of the CaLaAl<SUB>3</SUB>O<SUB>7</SUB>:Tb<SUP>3+</SUP> under a 254-nm UV light revealed an intense-green powder. The results showed that this kind of phosphor is potentially applicable in terms of UV-excited white LEDs.</P>
Singh, Vijay,Singh, N.,Dubey, Vikas,Singh, Pramod K.,Shinde, K.N.,Ravi Kanth Kumar, V.V. Elsevier 2018 OPTIK -STUTTGART- Vol.158 No.-
<P><B>Abstract</B></P> <P>Ce<SUP>3+</SUP>-doped CaAl<SUB>12</SUB>O<SUB>19</SUB> phosphors with different Ce<SUP>3+</SUP> contents, as well as those with Mg<SUP>2+</SUP> codoped powders, were successfully synthesized using a rapid combustion method (<5 min) for this paper. The powders were well characterized by the X-ray diffraction (XRD) and photoluminescence (PL) techniques. The emission measurements upon a UV-light excitation (262 nm) showed the emission characteristics of the Ce<SUP>3+</SUP> ion that are due to the 5d–4 f transitions. The emission and excitation spectra were recorded as the Ce<SUP>3+</SUP> concentration was kept constant and the Mg<SUP>2+</SUP> concentration was varied. It became evident that the addition of the Mg<SUP>2+</SUP> along with the Ce<SUP>3+</SUP> resulted in increases of the PL intensity, and the reasons for this behavior are discussed.</P>
UV emission from Gd<sup>3+</sup> ions in LaAl<sub>11</sub>O<sub>18</sub> phosphors
Singh, Vijay,Singh, N.,Pathak, M.S.,Watanabe, S.,Gundu Rao, T.K.,Singh, Pramod K.,Dubey, Vikas Elsevier 2018 Optik Vol.157 No.-
<P><B>Abstract</B></P> <P>Phosphors with the composition La<SUB>1-x</SUB>Gd<SUB>x</SUB>Al<SUB>11</SUB>O<SUB>18</SUB> (x = 0.01–0.10) were synthesized by combustion at a furnace temperature of 500 °C. The formation of the as-prepared combustion products was confirmed by X-ray diffraction analysis. On excitation with 273 nm, an emission band for the Gd<SUP>3+</SUP> ion was observed at 314 nm. This band progressively enhanced with increasing Gd<SUP>3+</SUP> concentration. The phosphor with low concentrations of Gd<SUP>3+</SUP> ions exhibits prominent ESR lines with <I>g</I> <SUB>eff</SUB> ∼ 1.9, 2.0, 4.7, and 5.9. With high dopant concentrations, the spectrum shows features similar to those of a U-spectrum with dominant lines with <I>g</I> <SUB>eff</SUB> ∼ 2.0, 2.9, 4.6, and 6.1. Low field lines arise from distortions in the immediate environment of the Gd<SUP>3+</SUP> ion.</P>
Green emitting Tb doped LiBaB<sub>9</sub>O<sub>15</sub> phosphors
Singh, Vijay,Shinde, K.N.,Singh, N.,Pathak, M.S.,Singh, Pramod K.,Dubey, Vikas Elsevier 2018 OPTIK -STUTTGART- Vol.156 No.-
<P><B>Abstract</B></P> <P>A successful preparation of a Tb<SUP>3+</SUP>-doped LiBaB<SUB>9</SUB>O<SUB>15</SUB> phosphors was achieved through the use of a solution-combustion method. The preparation of the powders of the Tb<SUP>3+</SUP>-doped LiBaB<SUB>9</SUB>O<SUB>15</SUB> phosphor was confirmed by X-ray diffraction (XRD) results; furthermore, the size and morphology of these powders were further examined using a scanning electron microscope (SEM). A study of the luminescent proprieties under a UV excitation showed a dominant and strong green luminescent peak at 542nm that is due to the d–f transition. When monitored at 542nm, the excitation spectrum exhibited a broad band centered at 230nm and several weak peaks in the wavelength range of 300–400nm that are attributed to the f-d transitions and the intra-4f-4f transitions of the Tb<SUP>3+</SUP> ions, respectively. The addition of the Tb<SUP>3+</SUP> concentration greatly improved the photoluminescent properties of the present phosphors, and the Commission International de I’Eclairage (CIE) chromaticity coordinates are located in the green region. The present study suggests that the potential applications of the Tb<SUP>3+</SUP>-doped LiBaB<SUB>9</SUB>O<SUB>15</SUB> phosphors might be in the lighting and display fields.</P>
Jeong, Hakyung,Singh, N.,Pathak, M.S.,Watanabe, S.,Gundu Rao, T.K.,Dubey, Vikas,Singh, Vijay Elsevier 2018 Optik Vol.157 No.-
<P><B>Abstract</B></P> <P>ZnMgAl<SUB>10</SUB>O<SUB>17</SUB> doped with varying concentrations of gadolinium phosphors were prepared by a solution combustion method. XRD, SEM, FTIR, photoluminescence and ESR techniques were used to characterize the as-prepared and annealed phosphors. A dominant line in the region g∼2.0 was observed along with another main line around 2.2 in the ESR spectrum of the as-prepared phosphor. Relatively weak lines were seen at about g∼2.7, 4.2 and 5.8, respectively. Distortions in the environment of Gd<SUP>3+</SUP> ion resulted in lines in the low-field region. Upon ultraviolet light excitation at 273nm, the sample exhibited a band at around 314nm which was assigned to <SUP>6</SUP>P<SUB>7/2</SUB> → <SUP>8</SUP>S<SUB>7/2</SUB> transition of Gd<SUP>3+</SUP>. ESR and optical analysis of the sample confirmed the presence of Gd<SUP>3+</SUP> in the ZnMgAl<SUB>10</SUB>O<SUB>17</SUB> matrix.</P>
Singh, Vijay,Singh, N.,Pathak, M.S.,Dubey, Vikas,Singh, Pramod K. Elsevier 2018 Optik Vol.155 No.-
<P><B>Abstract</B></P> <P>ZnAl<SUB>2</SUB>O<SUB>4</SUB> doped with varying concentrations of cerium phosphors were synthesized by combustion synthesis route. Two types of powder samples were examined: as-prepared and annealed at 800°C in air atmosphere. We investigated the structural, morphological and photoluminescence properties of cerium doped ZnAl<SUB>2</SUB>O<SUB>4</SUB> phosphors. Results of scanning electron microscopy, X-ray diffraction, photoluminescence investigations were presented.</P>
Synthesis, Characterization and Bioevaluation of New Tetrahydroquinazolines
Murthy, Y.L.N.,Acharyulu, P.V.N.,Dubey, P.K.,Sundari, T. Tirunala Korean Chemical Society 2008 대한화학회지 Vol.52 No.3
새로운 다섯개의 tetrahydroquinazolines 의 합성과 구조 결정 및 생물학적 평가는 보고 되었다. 최초에 준비된 cyclohexanones는 목표분자를 얻기 위한 synthon으로 사용되어졌다. 이들은 치환된 벤즈알데히드와 결합되어졌고, 얻어진 chalcone은 구아니딘 염산염으로 처리했다. 모든 분자들은 인간세포에 무독하며 상당한 항균성을 보여줬다. The synthesis, characterization and bioevaluation of five new tetrahydroquinazolines was reported. Initially cyclohexanones were prepared and they were used as synthons to get the target molecules. These were condensed with substituted benzaldehydes and the resulting chalcones were treated with guanidine hydrochloride . All the molecules were non-toxic to human cells and showed significant antibacterial activity.
Singh, Vijay,Pathak, M.S.,Singh, N.,Dubey, Vikas,Singh, Pramod K. Elsevier 2018 Optik Vol.152 No.-
<P><B>Abstract</B></P> <P>LiAl<SUB>5</SUB>O<SUB>8</SUB> doped with varying concentrations of Ce<SUP>3+</SUP> were synthesized by a combustion route. Powder X-ray diffraction and scanning electron microscopy techniques were used to characterize the as-prepared and annealed phosphors. The luminescence intensity decreased after annealing the samples at 800°C for 2h in air. These results indicate the possibility of fabrication of high quality Ce<SUP>3+</SUP> doped LiAl<SUB>5</SUB>O<SUB>8</SUB> phosphor even at furnace temperature 500°C via a simple process.</P>
Singh, Vijay,Sivaramaiah, G.,Singh, N.,Rao, J. L.,Dubey, Vikas,Singh, Pramod K. Springer-Verlag 2018 Journal of materials science. Materials in electro Vol.29 No.8
<P>Fe-doped CaAl12O19 was prepared via a simple combustion route. The formation of the as-prepared and post-heated combustion products was confirmed using an XRD analysis. The EPR spectrum of this sample exhibited a number of resonance signals. The paramagnetic centers have been quantified at different g factors in the range of 19.3-1.14. These resonance signals are attributed to pairs of Fe3+ ions. The resonance signal at a g value of similar to 4.2 is attributed to the axial-symmetry tetrahedral site. The resonance signal at a g value of similar to 2.0 is attributed to the presence of Fe3+ ions in an axial-symmetry octahedral site. The EPR parameters of the post-heated CaAl12O19:Fe3+ sample at room temperature and 110 K were calculated and compared.</P>