The ultrafast nonlinear optical response and multi-photon absorption of a new metal complex in the near-infrared spectral range

Kiran, A J,Lee, H W,Sampath Kumar, H C,Rudresha, B J,Bhat, B R,Yeom, D-I,Kim, K,Rotermund, F IOP Publishing 2010 Journal of optics Vol.12 No.3

<P>A new coordination compound, chloro(1,10-phenanthroline-<I>N</I>, <I>N</I><SUP>′</SUP>)(triphenylphosphine)copper(I) dichloromethane, incorporated in poly(methyl methacrylate) exhibits superior nonlinear optical properties in the near-infrared spectral region. Its nonlinear response time and third-order nonlinear optical susceptibility at 800 nm are ≤ 90 fs and 1.8 × 10<SUP> − 10</SUP> esu, respectively. Considerable nonlinear absorption is observed with this sample, near 800 and 1250 nm. The contribution of the excited states to the total nonlinear absorption process is discussed. The results reveal the potential of this newly designed compound for multi-photon absorption-based photonic applications.</P>

Pyknodysostosis: report of a rare case with review of literature

Kiran Kumar Kotagudda Ramaiah,Giju Baby George,Sheeba Padiyath,Rupak Sethuraman,Babu Cherian 대한영상치의학회 2011 Imaging Science in Dentistry Vol.41 No.4

Pyknodysostosis is a rare autosomal recessive disorder characterized by the post natal onset of short limbs, short stature, and generalized hyperostosis along with acro-osteolysis with sclerosis of the terminal phalanges, a feature that is considered essentially pathognomonic. Other features include persistence of fontanelles, delayed closure of sutures, wormian bones, absence of frontal sinuses, and obtuse mandibular gonial angle with relative mandibular prognathism. We report a case of 17-year-old girl who presented with a chief complaint of retention of deciduous teeth. General physical examination demonstrated short stature, frontal and parietal bossing, depressed nasal bridge,beaked nose, hypoplastic midface, wrinkled skin over the finger tips, and nail abnormalities. Radiographs showed multiple impacted permanent and supernumerary teeth, hypoplastic paranasal sinuses with acro-osteolysis of terminal phalanges, and open fontanelles, and sutures along with wormian bones in the lambdoidal region.

Three-dimensional finite element modeling of pulsed AC gas metal arc welding process

Kiran, D. V.,Cheon, J.,Arif, N.,Chung, H.,Na, S. J. Springer Science + Business Media 2016 INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TE Vol.86 No.5

<P>The behavior of the welding arc in the pulsed DC and AC gas metal arc welding processes was studied using real-time recorded current, voltage waveforms, and synchronized high-speed video at different electrode negative (EN) ratios for a constant wire feed rate. The regression equations were developed to predict the arc root dimensions as a function of welding current, voltage, time, and the EN ratio. A methodology was proposed to estimate the available energy rate distribution to the electrode and the base plate during the positive and negative cycles in pulsed AC gas metal arc welding (pulsed AC-GMAW) process. For an approximately equal peak positive current, the increase in the pulse time enhanced the molten electrode droplet diameter, arc plasma distribution, and the arc root dimensions. The fraction of the available arc energy rate supplied to the base plate was higher in positive pulse when compared to the negative pulse. A three-dimensional finite element modeling of pulsed DC-GMAW and pulsed AC-GMAW processes was performed to estimate the weld pool profile and temperature distribution in the weldment. The computed weld width, penetration, and the thermal cycles were in reasonable agreement with the corresponding experimental results. The peak temperature of the region in the weld pool near to the Gaussian distributed heat source experience fluctuations which were in synchronization with the current waveform. Increase in the EN ratio decreased the peak temperature while increased the cooling rate in the weldment. This reduced the bainite phase and enhanced the martensite phase in the weldment.</P>

Effect of accelerators with waste material on the properties of cement paste and mortar

Kiran Devi,Babita Saini,Paratibha Aggarwal 사단법인 한국계산역학회 2018 Computers and Concrete, An International Journal Vol.22 No.2

Accelerators are used to speed up the construction by accelerating the setting time which helps in early removal of formwork thus leading to faster construction rate. Admixtures are used in mortar and concrete during or after mixing to improve certain properties of material which cannot be achieved in conventional cement mortar and concrete. The various industrial by products make nuisance and are hazardous to ecosystem as well. These wastes can be used in the construction industries to reduce the consumption of cement/aggregates, cost; and save the energy and environment by utilising waste and eliminate their disposal problem as well. The effect of calcium nitrate and triethanolamine (TEA) as accelerators and marble powder (MP) as waste material on the various properties of cement paste and mortar has been studied in the present work. The replacement ratio of MP was 0-10% @ 2.5% by weight of cement. The addition of calcium nitrate was 0% and 1%; and variation of addition of TEA was 0-0.1@ 0.025% and 0.1-1.0@ 0.1% by weight of cement. On the basis of setting time, some mix proportions were selected and further investigated. Setting time and soundness of cement paste; compressive strength and microstructure of mortar mix of selected mix proportions were studied experimentally at 3, 7 and 28 days aging. Results showed that use of MP, calcium nitrate, TEA and their combination reduced setting time of cement paste for all the mixes. Addition of calcium nitrate increased the compressive strength at all curing ages while MP and TEA decreased the compressive strength. The mechanism of additives was discussed through scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis of the specimens.

Multiple myeloma presenting with a maxillary lesion as the first sign

Kiran Kumar Kotagudda Ramaiah,Vajendra Joshi,Shilpa Ravishankar Thayi,Pathalapate Sathyanarayana,Prashant Patil,Zaheer Ahmed 대한영상치의학회 2015 Imaging Science in Dentistry Vol.45 No.1

Multiple myeloma is a clonal neoplastic proliferation of terminally differentiated B-lymphocytes involving the skeletal system in a multifocal fashion. Its oral manifestations are less common in the maxilla than in the mandible due to the lower amount of hemopoietic bone marrow in the maxilla. We report the case of a 50-year-old man who presented with a mass in the left maxillary alveolar region with tooth mobility. The mass had become enlarged after the teeth were extracted 15 days previously. Radiographs demonstrated multiple punched-out radiolucent lesions in the skull and pelvic region. Computed tomography images showed a soft tissue density mass in the left maxilla, eroding the floor and walls of the maxillary sinus. Although several analytical techniques were used to characterize the lesion, it was finally confirmed as multiple myeloma through immunohistochemistry.

Variation of embryonic diapause induction in bivoltine silkworm Bombyx mori L (Lepidoptera: Bombycidae) under controlled conditions

( 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.

Designing novel chalcone single crystals with ultrafast nonlinear optical responses and large multi-photon absorption coefficients

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).

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.

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.