Temperature Dependent Current-Voltage and Capacitance-Voltage Characteristics of an Au/n-Type Si Schottky Barrier Diode Modified Using a PEDOT:PSS Interlayer

Khurelbaatar, Z.,Shim, K.-H.,Cho, J.,Hong, H.,Reddy, V.R.,Choi, C.-J. JAPAN INSTITUTE OF METALS 2015 MATERIALS TRANSACTIONS Vol.56 No.1

<P>The temperature dependence of the current-voltage (I-V) and capacitance-voltage (C-V) characteristics of an Au/n-type Si Schottky barrier diode (SBD) with a PEDOT:PSS interlayer was investigated. The SBD parameters, such as Schottky barrier height (Phi(B)), ideality factor (n), saturation current (I-o), doping concentration (N-D), and series resistance (R-s), were obtained as a function of temperature. The Richardson constant (A**) obtained from the In(I-o/T-2) versus 1000/T plot was much less than the theoretical value for n-Si. The mean Schottky barrier height ((Phi) over bar (bo)) and standard deviation (sigma(0)) calculated using the apparent Schottky barrier height (Phi(ap)) versus 1/2kT plot were 1.26 eV and 0.15 eV, respectively. From a fit of the modified Richardson plot of In(I-0/T-2) - (q sigma)(2)/2(kT)(2) versus 1000/T, the A** was extracted as 134 A/cm(2)K(2), which was close to the theoretical value of the n-Si. The interface state densities obtained from the Au/PEDOT:PSS/n-Si SBD decreased with increasing temperature. Furthermore, the conduction mechanism dominating the reverse-bias leakage current in Au/PEDOT:PSS/n-Si SBD was described and discussed.</P>

Molecular insights into the role of genetic determinants of congenital hypothyroidism

Kollati, Yedukondalu,Akella, Radha Rama Devi,Naushad, Shaik Mohammad,Patel, Rajesh K.,Reddy, G. Bhanuprakash,Dirisala, Vijaya R. Korea Genome Organization 2021 Genomics & informatics Vol.19 No.3

In our previous studies, we have demonstrated the association of certain variants of the thyroid-stimulating hormone receptor (TSHR), thyroid peroxidase (TPO), and thyroglobulin (TG) genes with congenital hypothyroidism. Herein, we explored the mechanistic basis for this association using different in silico tools. The mRNA 3'-untranslated region (3'-UTR) plays key roles in gene expression at the post-transcriptional level. In TSHR variants (rs2268477, rs7144481, and rs17630128), the binding affinity of microRNAs (miRs) (hsa-miR-154-5p, hsa-miR-376a-2-5p, hsa-miR-3935, hsa-miR-4280, and hsa-miR-6858-3p) to the 3'-UTR is disrupted, affecting post-transcriptional gene regulation. TPO and TG are the two key proteins necessary for the biosynthesis of thyroid hormones in the presence of iodide and H₂O₂. Reduced stability of these proteins leads to aberrant biosynthesis of thyroid hormones. Compared to the wild-type TPO protein, the p.S398T variant was found to exhibit less stability and significant rearrangements of intra-atomic bonds affecting the stoichiometry and substrate binding (binding energies, ΔG of wild-type vs. mutant: -15 vs. -13.8 kcal/mol; and dissociation constant, K_d of wild-type vs. mutant: 7.2E^-12 vs. 7.0E^-11 M). The missense mutations p.G653D and p.R1999W on the TG protein showed altered ΔG(0.24 kcal/mol and 0.79 kcal/mol, respectively). In conclusion, an in silico analysis of TSHR genetic variants in the 3'-UTR showed that they alter the binding affinities of different miRs. The TPO protein structure and mutant protein complex (p.S398T) are less stable, with potentially deleterious effects. A structural and energy analysis showed that TG mutations (p.G653D and p.R1999W) reduce the stability of the TG protein and affect its structure-functional relationship.

Electrical and mechanical properties of diluted magnetic semiconductor Zn_1-xMn_xS nanocrystalline films

Sreekantha Reddy, D.,Kang, B.,Yu, S.C.,Dwarakanadha Reddy, Y.,Sharma, S.K.,Gunasekhar, K.R.,Rao, K.N.,Sreedhara Reddy, P. Elsevier 2009 Current Applied Physics Vol.9 No.2

Nanostructured Zn<SUB>1-x</SUB>Mn<SUB>x</SUB>S films (0=<x=<0.25) were deposited on glass substrates by simple resistive thermal evaporation technique. All the films were deposited at 300K in a vacuum of 2x10<SUP>-6</SUP>m bar. All the films temperature dependence of resistivity revealed semiconducting behaviour of the samples. Hot probe test revealed that all the samples exhibited n-type conductivity. The nanohardness of the films ranges from 4.7 to 9.9GPa, Young's modulus value ranging 69.7-94.2GPa.

Electrical and mechanical properties of diluted magnetic semiconductor Zn1-xMnxS nanocrystalline films

D. Sreekantha Reddy,강병원,유성초,Y. Dwarakanadha Reddy,S.K. Sharma,K.R. Gunasekhar,K.N. Rao,P. Sreedhara Reddy 한국물리학회 2009 Current Applied Physics Vol.9 No.3

Nanostructured Zn1-xMnxS films (0 ≼ x ≼ 0.25) were deposited on glass substrates by simple resistive thermal evaporation technique. All the films were deposited at 300 K in a vacuum of 2 × 10-6 m bar. All the films temperature dependence of resistivity revealed semiconducting behaviour of the samples. Hot probe test revealed that all the samples exhibited n-type conductivity. The nanohardness of the films ranges from 4.7 to 9.9 GPa, Young’s modulus value ranging 69.7–94.2 GPa.

Cloning and Characterization of a Novel Carboxylesterase Gene from Cow Rumen Metagenomic Library

Shah Md. Asraful Islam(아스라풀 이스람),Min Keun Kim(김민근),Renukaradhya K. Math(아라디아),Srinivasa Reddy R.N.(스리니 래디),Eun Jin Kim(김은진),Jungho Kim(김정호),Hoon Kim(김훈),Han Dae Yun(윤한대) 한국생명과학회 2010 생명과학회지 Vol.20 No.9

한우의 반추위에서 게놈 DNA를 분리하여 메타게놈 은행을 구축한 다음 carboxylesterase를 암호화하는 유전자를 클로닝 및 유전자를 선별하였다. 선별된 유전자의 DNA 염기서열 및 아미노산 서열을 분석하고 유전산물의 생화학적인 특성을 조사하였다. est1R 유전자는 2,465 bp로 366개의 아미노산 잔기를 가진 단백질을 암호화하였으며 이 단백질의 이론적인 분자량은 61,166 Da이었다. Est1R단백질은 PNB carboxylesterase (P37967), acetylcholinesterase(1EEAA) 및 chain A (1H23A)와 각각 5.9%, 6.1%, 6.1% 상동성을 가지고 있었다. 이러한 검색 결과 기존의 알려진 lipase 및esterase와의 상동성이 낮은 것으로 보아 새로운 그룹의 효소로 추정된다. Est1R효소의 최적 pH는 7.0 근방이었으며 최적 온도는 40℃ 부근이었다. 한편 10% 유기용매를 함유한 기질의 효소활성측정에서 대조구에 비해 methanol은 95%의 상대적인 활성을 가진 반면에 hexane 용액에서는 그 활성이 반으로 감소하였다. 따라서 유기용매 농도의 작용성에 따라 이 효소의 산업적 이용성도 가능하리라 추정된다. The gene encoding esterase enzyme was cloned from a metagenomic library of cow rumen bacteria. The esterase gene (est1R) was 2,465 bp in length, encoding a protein of 366 amino acid residues, and the molecular weight of the enzyme was 61,166 Da. Est1R of rumen cosmid library shared 5.9% amino acid identity with Est1R (P37967) of PNB carboxylesterase, 6.1% with Est1R (1EEAA) of acetylcholinesterase and 6.1% with Est1R (1H23A) of chain A. BlastP in NCBI database analysis of Est1R revealed that it was not homologous to previous known lipases and esterases. Est1R showed optimum activity at pH 7.0 and 40℃. On the other hand, the enzyme was found to be most active without organic solvent, followed by 95% activity with methanol, and the enzyme activity was highly affected by hexane (lost 51% activity). Therefore, the novel esterase gene est1R is likely obtainable from cow rumen metagenome and may be utilized for industrial purposes.

On general order prime graph of a finite group

R. RAJENDRA,P. S. K. Reddy 장전수학회 2014 Proceedings of the Jangjeon mathematical society Vol.17 No.4

On general order prime graph of a finite group

A 16-mW 78-dB SNDR 10-MHz BW CT <tex> $\Delta \Sigma$</tex> ADC Using Residue-Cancelling VCO-Based Quantizer

Reddy, K.,Rao, S.,Inti, R.,Young, B.,Elshazly, A.,Talegaonkar, M.,Hanumolu, P. K. IEEE 2012 IEEE journal of solid-state circuits Vol.47 No.12

<P>This paper presents a continuous-time (CT) ΔΣ modulator using a VCO-based internal quantizer. It incorporates a nonlinear VCO as the second stage in a two-stage residue canceling quantizer (RCQ) and mitigates the impact of its nonlinearity by spanning only a small region of the VCO's V-to-F nonlinear tuning curve. The order of noise shaping is increased by placing the RCQ in a continuous-time ΔΣ loop. Using only a first order loop filter, the proposed ΔΣ modulator achieves second order noise shaping. Fabricated in a 90-nm CMOS process, the prototype modulator occupies an active area of 0.36 mm<SUP>2</SUP> and consumes 16 mW power. It achieves a peak SNDR of 78.3 dB in 10-MHz bandwidth and an SFDR of better than 85 dB when clocked at 600 MHz. The figure of merit of the modulator is 120 fJ/conv-step.</P>

Determination of the Minority Carrier Diffusion Length of SnS Using Electro-Optical Measurements

K. T. Ramakrishna Reddy,P. A. Nwofe,R. W. Miles 대한금속·재료학회 2013 ELECTRONIC MATERIALS LETTERS Vol.9 No.3

The minority carrier diffusion length of the “absorber layer” in a solar cell is generally accepted to be one of the most important parameters that govern the performance of a solar cell device. In this work, thin films of SnS have been thermally evaporated onto cadmium sulphide/indium tin oxide/glass substrates, to fabricate heterojunction solar cell devices. The minority carrier diffusion length was determined for the first time for SnS layers using spectral response measurements in conjunction with optical absorption coefficient versus wavelength measurements. The minority carrier diffusion length was determined to be in the range 0.18 -0.23 μm for the SnS/CdS devices investigated in this work.

Switching Invariant Neighborhood Signed Graphs

R. Rangarajan,M. S. Subramanya,P. S. K. Reddy 장전수학회 2011 Proceedings of the Jangjeon mathematical society Vol.14 No.2

A signed graph (marked graph) is an ordered pair S = (G, ) (S = (G, μ)),where G = (V,E) is a graph called the underlying graph of S and [수식] is a function. The neighborhood graph of a graph G = (V,E), denoted by N(G),is a graph on the same vertex set V , where two vertices in N(G) are adjacent if, and only if, they have a common neighbor. Analogously, one can define the neighborhood signed graph N(S) of a signed graph [수식] as a signed graph,[수식] where N(G) is the underlying graph of N(S), and for any edge e = uv in N(S),[수식] where for any v 2 V , μ(v) =Y u)μ(v), where for any v 2 V , μ(v) = u2N(v) (uv). In this paper, we characterize signed graphs S for which S N(S), Sc N(S) and N(S) J(S), where J(S) and Sc denotes jump signed graph and complement of signed graph of S respectively.

Enhanced photocatalytic activity of nanostructured titanium dioxide/polyaniline hybrid photocatalysts

Reddy, K.R.,Karthik, K.V.,Prasad, S.B.B.,Soni, S.K.,Jeong, H.M.,Raghu, A.V. Pergamon Press 2016 Polyhedron Vol.120 No.-

<P>An organo-inorganic photocatalytic nanocomposite material based on conjugated polymer, polyaniline (PANI) with titanium dioxide (TiO2) nanoparticles has been developed by performing in situ chemical oxidative polymerization of aniline with ammonium persulfate (APS) oxidant in the presence of hydrothermally synthesized TiO2 nanoparticles. The structural and morphological properties of TiO2/PANI nanocomposites were analyzed by transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR), respectively. The TEM results of the TiO2/PANI nanocomposites showed that TiO2 nanoparticles of 5-10 nm of sizes are dispersed in the PANI matrix. FT-IR spectra show that the TiO2/PANI nanocomposites are almost identical to the structure of PANI alone. The photocatalytic activities of the nanocomposites were evaluated by the photocatalytic degradation of Rhodamine B (RhB), Methylene Blue (MB) and phenol in the presence of UV-light irradiation. The composite catalysts exhibited higher photocatalytic activity for the degradation of organic pollutants than unmodified TiO2 nanoparticles, which is due to sensitizing effect of PANI. (C) 2016 Published by Elsevier Ltd.</P>