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4-Hydroxy-2’-Nitrodiphenyl Ether Analogues as Novel Tyrosinase Inhibitors
Kiran Sapkota,이은영,Jae-Ho Yang,권영주,최종원,나영화 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.5
Tyrosinase ubiquitously existing from microorganisms to animals and plants is known to be the most critical and rate limiting enzyme during melanin biosynthesis. In order to develop new tyrosinase inhibitor we have synthesized 14diphenyl ether compounds possessing hydroxyl, bromo, and nitro groups in the structure. Among the compounds prepared, 18 and 19 have shown much stronger inhibition of tyrosinase monophenolase function than arbutin used as a positive control. Both compounds 18 and 19 possess para-hydroxyphenyl moiety in their structure, which might reinforce the importance of p-hydroxyphenyl group in the tyrosinase inhibitory process. In the DPPH radical scavenging activity test, none of the compounds even 18 and 19 showed significant antioxidant activity. The results suggest that elaborate adjustment of diphenyl ether analogues with proper substituents have potential to be developed as new skin whitening agents working on the tyrosinase function.
Arc interaction and molten pool behavior in the three wire submerged arc welding process
Kiran, Degala Venkata,Cho, Dae-Won,Song, Woo-Hyun,Na, Suck-Joo Elsevier 2015 INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER - Vol.87 No.-
<P><B>Abstract</B></P> <P>A three-dimensional numerical heat transfer and fluid flow model is developed to understand the temperature distribution and molten pool behavior in a three wire submerged arc welding process. The model solves the equations of the conservation of mass, momentum, and energy along with the volume of fluid method. The volume of fluid method is used to track the shape of the free surface. Further, a physical model is developed to estimate the arc center displacement. For a given welding condition, connecting the leading electrode with direct current electrode positive polarity, the middle and trailing electrodes with trapezoidal alternating current waveform displayed deeper weld pools when compared to the sine waveforms. Within the range of welding conditions considered in the present work, weld width is significantly influenced by the leading arc whereas the penetration by the middle and trailing arcs. The computed weld width and penetration are in fair agreement with the corresponding experimental results.</P>
Biocompatability of carbon nanotubes with stem cells to treat CNS injuries
Kiran Kumar Bokara,Jong Youl Kim,Young Il Lee,Kyungeun Yun,Tom J Webster,Jong Eun Lee 대한해부학회 2013 Anatomy & Cell Biology Vol.46 No.2
Cases reporting traumatic injuries to the brain and spinal cord are extended range of disorders that affect a large percentage of the world's population. But, there are only few effective treatments available for central nervous system (CNS) injuries because the CNS is refractory to axonal regeneration and relatively inaccessible to many pharmacological treatments. The use of stem cell therapy in regenerative medicine has been extensively examined to replace lost cells during CNS injuries. But, given the complexity of CNS injuries oxidative stress, toxic byproducts, which prevails in the microenvironment during the diseased condition, may limit the survival of the transplanted stem cells affecting tissue regeneration and even longevity. Carbon nanotubes (CNT) are a new class of nanomaterials, which have been shown to be promising in different areas of nanomedicine for the prevention, diagnosis and therapy of certain diseases, including CNS diseases. In particular, the use of CNTs as substrates/scaffolds for supporting the stem cell differentiation has been an area of active research. Single-walled and multi-walled CNT's have been increasingly used as scaffolds for neuronal growth and more recently for neural stem cell growth and differentiation. This review summarizes recent research on the application of CNT-based materials to direct the differentiation of progenitor and stem cells toward specific neurons and to enhance axon regeneration and synaptogenesis for the effective treatment of CNS injuries. Nonetheless, accumulating data support the use of CNTs as a biocompatible and permissive substrate/scaffold for neural cells and such application holds great potential in neurological research.
Microwave-Assisted Synthesis of 3-Styrylchromones in Alkaline Ionic Liquid
Kiran F. Shelke,Suryakant B. Sapkal,Nana V. Shitole,Bapurao B. Shingate,Murlidhar S. Shingare 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.12
A simple, highly efficient and environmentally benign method for the synthesis of 3-styrylchromones from 3-formylchromones and 4-nitrophenylacetic acid/4-nitrotolune in the presence of catalytic amount of basic ionic liquid 1-butyl-3-methylimidazolium hydroxide [(bmim)OH] carried out under the influence of microwave irradiation. This method gives remarkable advantages such as, short reaction times, simple work-up procedure and moderate to good yields. The ionic liquid was successfully reused for four cycles without significant loss of activity.
Kiran F. Shelke,Suryakant B. Sapkal,Swapnil S. Sonar,Balaji R. Madje,Bapurao B. Shingate,Murlidhar S. Shingare 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.5
Boric acid (BO3H3) is an inexpensive, efficient and mild catalyst for the synthesis of 2,4,5-triaryl-1H-imidazoles in excellent yields from the one-pot three-component condensation of benzil/benzoin, an aldehydes and ammonium acetate in aqueous media under ultrasound at room temperature. The remarkable advantages offered by this method are green catalyst, mild reaction conditions, simple procedures, much faster reactions and excellent yield of products.
Kiran, A.J.,Lee, H.W.,Ravindra, H.J.,Dharmaprakash, S.M.,Kim, K.,Lim, H.,Rotermund, F. Elsevier 2010 Current Applied Physics Vol.10 No.5
A chalcone single crystal, 1-(4-chlorophenyl)-3-(4-methoxyphenyl)prop-2-en-1-one that is transparent over the visible to infrared region is introduced as a new potential material to third-order nonlinear optical applications. The crystal exhibits ultrafast optical response (@?90 fs) and large optical nonlinearity in the wavelength range 800-1200 nm. A very large effective two-photon absorption coefficient β<SUB>eff</SUB>exceeding 120 cm/GW can be obtained with this chalcone crystal, at a low intensity threshold of 41 MW/cm<SUP>2</SUP> The mechanism of nonlinear absorption at different levels of intensity has been discussed. The crystal shows no damage against the laser pulse intensity as high as 8 GW/cm<SUP>2</SUP> We discuss the molecular and crystal designing of chalcones with large and ultrafast optical nonlinearity combined with low optical cut-off (<450 nm).
Free vibration and static analysis of functionally graded skew magneto-electro-elastic plate
Kiran, M.C.,Kattimani, S.C. Techno-Press 2018 Smart Structures and Systems, An International Jou Vol.21 No.4
This article presents a finite element (FE) model to assess the free vibration and static response of a functionally graded skew magneto-electro-elastic (FGSMEE) plate. Through the thickness material grading of FGSMEE plate is achieved using power law distribution. The coupled constitutive equations along with the total potential energy approach are used to develop the FE model of FGSMEE plate. The transformation matrix is utilized in bringing out the element matrix corresponding to the global axis to a local axis along the skew edges to specify proper boundary conditions. The effect of skew angle on the natural frequency of an FGSMEE plate is analysed. Further, the study includes the evaluation of the static behavior of FGSMEE plate for various skew angles. The influence of skew angle on the primary quantities such as displacements, electric potential, and magnetic potential, and secondary quantities such as stresses, electric displacement and magnetic induction is studied in detail. In addition, the effect of power-law gradient, thickness ratio, boundary conditions and aspect ratio on the free vibration and static response characteristics of FGSMEE plate has been investigated.
( Kiran Rudramuni ),( Bharath Kumar Neelaboina ),( Shivkumar ),( Mir Nisar Ahmad ),( Sukhen Roy Chowdhury ) 한국잠사학회 2021 International Journal of Industrial Entomology Vol.43 No.2
Mulberry silkworm is classified into uni, bi and multivoltine based on the frequency of diapause incidence. The variation in the incidence of diapause in bivoltine silkworm provides a unique opportunity to study the process of evolution of adaptive plasticity towards seasonal variations. The diapause expression in bivoltine silkworm is highly variable and is determined by environmental factors experienced by the maternal generation. Diapause in natural populations is functionally associated with the overwintering mechanism that facilitates survival in harsh winter conditions. In contrast, under standard commercial rearing conditions, the domesticated bivoltine silkworm is known to enter diapause in every generation. This paper presents a short review of the literature dealing with the role of temperature, photoperiod, diapause hormone and its receptor in diapause induction. Also, we briefly review the incidence of non-diapause eggs in bivoltine silkworm under controlled conditions.