Effect of zinc oxide incorporation of poly (aniline)-titanium dioxide ternary nanocrystalline photo-anode for dye-sensitized solar cell applications

Velu Kuppu Sakthi,Kamaraj Eswaran,Sadagopan Jayakumar,Sonaimuthu Mohandoss,Ahmad Naushad,Alagarasan Jagadeesh Kumar,Ravisankar Parkavi,Lee Yong Rok 한국물리학회 2024 Current Applied Physics Vol.58 No.-

In this work, we have developed optically transparent zinc oxide nanoparticles doped with highly efficient of poly (aniline)-titanium dioxide (PANI/TiO2/ZnO) ternary composites were prepared by simple chemical oxidative polymerization method and its used as photo-anode for dye-sensitized solar cell (DSSC) applications. The as prepared PANI/TiO2/ZnO characterized by the various techniques such as FT-IR, XRD, HR-TEM, SAED, FE-SEM, AFM, and UV–Visible analysis. Morphological analysis was observed in the surface morphology of ZnO doped PANI/TiO2 in crystalline nature. The topographical AFM images were also observed in crystalline nature. Tauc plot analysis were examined the optical band-gap energy (2.95 eV) of PANI/TiO2/ZnO. The DSSCs assembled and as prepared PANI/TiO2, PANI/ZnO, TiO2/ZnO, PANI/TiO2/ZnO were used as photo-anode, 1- hexyl-3-methylimidazolium iodide containing the iodide/triiodide redox mediator used as the electrolyte, platinum paste used as a counter electrode. Among the devices, PANI/TiO2/ZnO photo-anode gives 8.31% efficiency.

Biofabrication of carbon quantum dots and their food packaging applications: a review

Velu Manikandan,민세철 한국식품과학회 2023 Food Science and Biotechnology Vol.32 No.9

Carbon quantum dots (CQDs) are an emerging class of novel carbon nanomaterials (< 10 nm). These zero-dimensional CQDs have recently invoked significant interest due to their high fluorescence ability, strong electronic conductivity, biocompatibility, excellent chemical stability, non-toxicity, and environmental safety. Bio-fabrication of CQDs from organic resources remains attractive owing to their excellent functional properties. An emerging class of CQDs is fabricated by various conventional methods. However, these methods need many chemical agents and instrument facilities. Bio-fabrication of CQDs has a lot of benefits because of its simple fabrication and eco-friendly. Therefore, the green synthesized CQDs are considered optimistic candidates for developing novel functional materials for food packaging applications. Thus, it is important to investigate the latest update on green-based CQDs for food packaging applications. This current review paper discusses the physicochemical properties of CQDs, the bio-fabrication of CQDs, and the fluorescent properties of CQDs along with their food packaging applications.

Fabrication, optimization, and characterization of noble silver nanoparticles from sugarcane leaf ( <i>Saccharum officinarum</i> ) extract for antifungal application

Velu, Manikandan,Lee, Jeong-Ho,Chang, Woo-Suk,Lovanh, Nanh,Park, Yool-Jin,Jayanthi, Palaniyappan,Palanivel, Velmurugan,Oh, Byung-Taek Springer Berlin Heidelberg 2017 3 Biotech Vol.7 No.2

<P>Metal nanoparticles obtained from green route are gaining significant prominence as a result of their potential applications in nanomedicine and material engineering. Overall metal nanoparticles studied, silver nanoparticles (AgNPs) clutch prominent place in nanoparticles research field. Herein, we have reported the green synthesis of <I>Saccharum officinarum</I> leaf biomass extract-mediated synthesis of AgNPs. Initial nanoparticle production was confirmed by visual observation as color change from light yellow to bright brown color with yellow shade and spectrophotometrically at 450 nm and the various reaction conditions were optimized. The FTIR spectra of the biomass extract and synthesized AgNPs authorized the presence of phyto constituents as capping agent. The High Resolution-Transmission Electron Microscopy (HR-TEM) analyses confirm the morphology and the average particle size of AgNPs as ~28.2 nm. The crystalline nature oxide state and mean particle diameter of AgNPs were confirmed by X-ray diffraction (XRD) analysis, Selected Area Electron Diffraction (SAED) pattern and face-centered cubic (FCC). The obtained AgNPs show moderate to good antifungal activity against <I>Phytophthora capsici</I>, <I>Colletotrichum acutatum</I> and <I>Cladosporium fulvum</I> as 10, 12 and 14 mm zones of inhibition against synthesized AgNPs at 250 μg/well, respectively.</P>

Genomic Organization of Heat Shock Protein Genes of Silkworm Bombyx mori

Velu, Dhanikachalam,Ponnuvel, Kangayam M.,Qadri, Sayed M. Hussaini Korean Society of Sericultural Science 2007 International Journal of Industrial Entomology Vol.15 No.2

The Hsp 20.8 and Hsp 90 cDNA sequence retrieved from NCBI database and consists of 764 bp and 2582 bp lengths respectively. The corresponding cDNA homologus sequences were BLAST searched in Bombyx mori genomic DNA database and two genomic contigs viz., BAAB01120347 and AADK01011786 showed maximum homology. In B. mori Hsp 20.8 and Hsp 90 is encoded by single gene without intron. Specific primers were used to amplify the Hsp 20.8 gene and Hsp 90 variable region from genomic DNA by using the PCR. Obtained products were 216 bp in Hsp 20.8 and 437 bp in Hsp 90. There was no variation found in the six silkworm races PCR products size of contrasting response to thermal tolerance. The comparison of the sequenced nucleotide variations through multiple sequence alignment analysis of Hsp 90 variable region products of three races not showed any differences respect to their thermotolerance and formed the clusters among the voltinism. The comparison of aminoacid sequences of B. mori Hsps with dipteran and other insect taxa revealed high percentage of identity growing with phylogenetic relatedness of species. The conserved domains of B. mori Hsps predicted, in which the Hsp 20.8 possesses ${\alpha}-crystallin$ domain and Hsp 90 holds HATPase and Hsp 90 domains.

Metal ion-induced dual fluorescent change for aza-crown ether acridinedione-functionalized gold nanorods and quantum dots

Velu, Ranganathan,Won, Nayoun,Kwag, Jungheon,Jung, Sungwook,Hur, Jaehyun,Kim, Sungjee,Park, Nokyoung The Royal Society of Chemistry 2012 New journal of chemistry Vol.36 No.9

<P>Aza-crown ether acridinedione-functionalized quantum dots (ACEADD-QDs) and aza-crown ether acridinedione-functionalized gold nanorods (ACEADD-GNRs) have been developed as a pair for a fluorescent chemosensor detecting metal ions. The ACEADD-QDs have dual emissions at a visible wavelength of ∼430 nm from the acridinedione dye moiety and at a near-infrared (NIR) wavelength of ∼775 nm from the CdTeSe QDs. In the presence of Ca<SUP>2+</SUP> or Mg<SUP>2+</SUP> ions, the ACEADD-QD and ACEADD-GNR pair can form a sandwich complex mediated by the metal ion. The ACEADD-QD and ACEADD-GNR complex pair shows visible fluorescence enhancement from the acridinedione dye and concurrent fluorescence quenching from the NIR QD. The aza-crown ether complex results in the suppression of photoinduced electron transfer from the aza-crown ether to the acridinedione dye moiety. At the same time, the QD fluorescence can be effectively quenched by the nanometal surface energy transfer from the QD to the GNR. This ACEADD-QD and ACEADD-GNR pair can effectively transduce the selective binding event of crown ethers with metal ions into the simultaneous modulation of the enhancement in dye fluorescence and the quenching of QD emission, which can open a new strategy for ratiometric sensors that are selective and robust against the environment conditions.</P> <P>Graphic Abstract</P><P>A pair of aza-crown ether acridinedione-functionalized quantum dots and gold nanorods has been developed for a selective metal ion sensor <I>via</I> ratiometric fluorescence modulations. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2nj40444c'> </P>

Expression of the Heat Shock Protein Genes in Response to Thermal Stress in the Silkworm Bombyx mori

Velu, Dhanikachalam,Ponnuvel, Kangayam. M.,Qadri, Syed. M. Hussaini Korean Society of Sericultural Science 2008 International Journal of Industrial Entomology Vol.16 No.1

The expression of heat shock protein genes (Hsp 70, Hsp 40, Hsp 20.8 and Hsp 20.4) against thermal stress in silkworm Bombyx mori was performed through semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Upon exposure of silkworm to two temperature regimes ($38^{\circ}C$ and $42^{\circ}C$), significant change in the expression of Hsp gene was observed as compared to the control. Hsp 70 and Hsp 40 showed increased expression than the small heat shock protein genes Hsp 20.8 and Hsp 20.4. The Hsp 70 showed increased expression during the recovery period as compared to 1 hr thermal treatments ($38^{\circ}C$/1 hr and $42^{\circ}C$/1 hr). Whereas, Hsp 40, Hsp 20.8 and Hsp 20.4 genes showed higher expression level at initial stages that later gradually decrease during recovery period. Tissue specific expression of Hsp 70 showed variation in the level of expression amongst the tissues. The mid gut and fat body tissues showed higher expression than the cuticle and silk gland tissue. The Hsp 70, Hsp 40 gene expression was analyzed in thermotolerant (Nistari) and thermo susceptible silk worm strain (NB4D2) and results showed significant variation in their expression level. The Nistari showed higher expression of Hsp 70 and Hsp 40 genes than the NB4D2. These findings provide a better understanding of cellular protection mechanisms against environmental stress such as heat shock, as these Hsps are involved in an organism thermotolerance.

Rice Husk Ash와 실리카퓸을 혼입한 초기재령 콘크리트의 내구성능 평가

Velu Saraswathy,권성준(Seung-Jun Kwon) 한국콘크리트학회 2015 콘크리트학회논문집 Vol.27 No.4

Induction of Th1-Biased T Follicular Helper (Tfh) Cells in Lymphoid Tissues during Chronic Simian Immunodeficiency Virus Infection Defines Functionally Distinct Germinal Center Tfh Cells

Velu, Vijayakumar,Mylvaganam, Geetha Hanna,Gangadhara, Sailaja,Hong, Jung Joo,Iyer, Smita S.,Gumber, Sanjeev,Ibegbu, Chris C.,Villinger, Francois,Amara, Rama Rao The American Association of Immunologists, Inc. 2016 JOURNAL OF IMMUNOLOGY Vol.197 No.5

<P>Chronic HIV infection is associated with accumulation of germinal center (GC) T follicular helper (Tfh) cells in the lymphoid tissue. The GC Tfh cells can be heterogeneous based on the expression of chemokine receptors associated with T helper lineages, such as CXCR3 (Th1), CCR4 (Th2), and CCR6 (Th17). However, the heterogeneous nature of GC Tfh cells in the lymphoid tissue and its association with viral persistence and Ab production during chronic SIV/HIV infection are not known. To address this, we characterized the expression of CXCR3, CCR4, and CCR6 on GC Tfh cells in lymph nodes following SIVmac251 infection in rhesus macaques. In SIV-naive rhesus macaques, only a small fraction of GC Tfh cells expressed CXCR3, CCR4, and CCR6. However, during chronic SIV infection, the majority of GC Tfh cells expressed CXCR3, whereas the proportion of CCR4(+) cells did not change, and CCR6(+) cells decreased. CXCR3(+), but not CXCR3(-), GC Tfh cells produced IFN-gamma (Th1 cytokine) and IL-21 (Tfh cytokine), whereas both subsets expressed CD40L following stimulation. Immunohistochemistry analysis demonstrated an accumulation of CD4(+) IFN-gamma(+) T cells within the hyperplastic follicles during chronic SIV infection. CXCR3(+) GC Tfh cells also expressed higher levels of ICOS, CCR5, and alpha 4 beta 7 and contained more copies of SIV DNA compared with CXCR3(-) GC Tfh cells. However, CXCR3(+) and CXCR3(-) GC Tfh cells delivered help to B cells in vitro for production of IgG. These data demonstrate that chronic SIV infection promotes expansion of Th1-biased GC Tfh cells, which are phenotypically and functionally distinct from conventional GC Tfh cells and contribute to hypergammaglobulinemia and viral reservoirs.</P>

Studies on the Performance of Self Healing of Plastic Cracks Using Natural Fibers in Concrete

Saraswathy, Velu,Kwon, Seung-Jun,Karthick, Subbiah Korean Recycled Construction Resources Institute 2014 한국건설순환자원학회 논문집 Vol.2 No.2

Addition of fibers in cement or cement concrete may be of current interest, but this is not a new idea or concept. Fibers of any material and shape play an important role in improving the strength and deformation characteristics of the cement matrix in which they are incorporated. The new concept and technology reveal that the engineering advantages of adding fibers in concrete may improve the fracture toughness, fatigue resistance, impact resistance, flexural strength, compressive strength, thermal crack resistance, rebound loss, and so on. The magnitude of the improvement depends upon both the amount and the type of fibers used. In this paper, locally available waste fibers such as coir fibers, sisal fibers and polypropylene fibers have incorporated in concrete with varying percentages and l/d ratio and their effect on compressive, split, flexural, bond and impact resistance have been reported.

Stress Corrosion Behavior of Ungrouted Pretensioned Concrete Beams

Saraswathy, Velu,Lee, Han-Seung,Karthick, Subbiah,Kwon, Seung-Jun Hindawi Limited 2018 Advances In Materials Science And Engineering Vol.2018 No.1

<P>Prestressed concrete beams of size 150 × 150 × 1000 mm were designed, and two bonded cold-drawn 7 mm steel wires were stressed at 70% UTS under service conditions before concreting. The beams were cast with M40 grade concrete mix with various percentages of chlorides ranging from 0, 1, 2, and 3% by weight of cement and cured for 28 days. After 28 days, the stretching forces were released, the prestressing steel wire was allowed to regain its original length, the tensile stresses were transformed into a compressive stress in the concrete, and the stress corrosion behavior was assessed. Stress corrosion cracking (SCC) is due to the simultaneous action of stress, corrosive media, and material properties. The stress corrosion behavior of ungrouted pretensioned steel was assessed by using various electrochemical techniques such as electrochemical noise, open-circuit potential measurement, AC impedance, and potentiodynamic polarization measurements. The same experiments were conducted for rebars embedded in the concrete beam with various percentages of chlorides ranging from 0, 1, 2, and 3% by weight of chloride. After 30 days of exposure, the beams were tested for their flexural strength measurements to find out the load-bearing capacity.</P>