IR@CGCRI - Central Glass and Ceramic Research Institute (CSIR)
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COM Stone Dusting and Soft Tissue Ablation With Q-Switched Thulium Fiber Laser
No full textThe influence of the parameters of Q-switched thulium fiber laser at 1.94 mu m on human calcium oxalate monohydrate (COM) urinary stone and soft tissues has been investigated to determine its efficiency on stone fragmentation and tissue ablation along with surrounding thermal injury. The designed Q-switched thulium fiber laser can be operated with peak powers varying from 93 to 493 W, pulse duration from 350 to 750 ns, and repetition rates from 55 to 135 kHz at 9.5 W average power. Comparative effects on COM stone fragmentation rate and soft tissue ablation by using Q-switched and continuous wave (CW) thulium fiber laser have been studied. The stable pulse from the Q-switched thulium fiber laser at high repetition rate is effective for COM stone fragmentation with very fine particle size, average in the range of 47.85 mu m, called dusting, at the fragmentation rate of 12.75 mg/min. Soft tissue ablation employing the Q-switched thulium fiber laser is reasonably clean, leaving minimum residual carbonization of 170 mu m and heat-affected zone of 0.76 mm. The Q-switched thulium fiber laser produces two times narrower adjacent tissue damage zone along with four times lower charring region compared to the equivalent CW thulium fiber laser exposure in soft tissue
shRNA intercalation in CaAl-LDH nanoparticle synthesized at two different pH conditions and its comparative evaluation
No full textIn continuation with our previous report w.r.t the synthesis of phase pure and mixed phase calcium aluminum layered double hydroxide (CaAl-LDH) and its subsequent evaluation with regard to anticancer property, the present communication demonstrates the intercalation of plasmid encoded short hairpin RNA (shRNA) into the interlayer space of CaAl-LDH nanoparticle (precipitated both at pHs 8.5 and 12.5, designated as sample A and B respectively) by a simple technique to obtain the requisite loading, followed by evaluation of the cellular uptake and localization. The presence of interlayer carbonate anion (CO32-) as an impurity, were quantified both in the samples A and B, using ion chromatography, of which, the later exhibited a higher value (6.10 ppm) which in turn had hindered the intercalation of the shRNA, largely. Further, the cellular uptake using colon cancer cell line (HCT 116) could be correlated, based on the above data, as, for sample A, a threefold higher value (9.34%) was found in a period of 72 h, compared to sample B (3.54%), without using any transfection reagent. This observation was corroborated using confocal imaging to understand the internalization at the cellular level
Influence of spin-state transition on structural and other physical properties in Ba0.5Sr0.5Co0.8Fe0.2O3-delta ceramic
No full textWe explore, in detail, the remarkable influence of spin-state transition - low (S = 1/2) to high spin (S = 5/2) - on crystallographic, thermal, electrical, and mechanical properties in Ba0.5Sr0.5Co0.8Fe0.2O3-delta ceramic. The low to high spin transition takes place at T* similar to 600 K with a rather broad transition zone of nearly 200 K. We find that the electrical resistivity, mechanical stiffness and toughness, thermal expansion coefficient, and the crystallographic structure exhibit clear anomalous features around T*. The transition, however, appears to be isostructural Pm (3) over barm -> Pm (3) over barm (cubic -> cubic). Significant influence of spin-state transition on a variety of properties could have serious implications for several applications ranging from magnetic sensors to electrocatalysts to ion separation membranes
Polybenzimidazole-Clay Nanocomposite Membrane for PEM fuel cell: Effect of organomodifier structure
No full textIn this work, montmorillonite clay was organically modified using two surfactants which are largely different in their chemical structure - one is dimethyldihydrogenated ammonium chloride tallow (DDACT), that contains two long alkyl chains and the other is tributyl phosphonium molecule (TPB), a molecule containing short alkyl chains. The objective of the work is to study the effect of these surfactants' structure on the properties of OPBI for proton exchange membrane (PEM) fuel cell applications. The morphology study of the membranes using PXRD and TEM revealed intercalated nanostructures using both the clays. The increment in thermal stability and T-g was found to be higher in the case of TPB modified clay membranes than the tallow amine modified clay membranes. Acid doping and swelling studies were performed and the values again reflected the nature of the surfactant used with phosphonium cation containing membranes showing higher PA doping levels. Specific swelling volume of the membranes portrayed the controlled swelling behaviour of all the nanocomposite membranes. Proton conductivity of the membranes were found to be lower than the pristine OPBI owing to the tortuous conduction pathway created by the clay sheets
Impact Of Morphology On The Electrical And Photocatalytic Property Of Cds Nanostructures
No full textTuning the morphological features of nanoparticles has a great impact on the electrical, optical as well as photocatalytic property. In this study, we have synthesized cadmium sulphide (CdS) nanoflakes and CdS nanospheres via a simple chemical route. The average particle size of CdS nanosphere and CdS nanoflakes calculated from small-angle X-ray scattering studies are 22 nm and (diameter similar to 5 nm and length similar to 70 nm) respectively. Due to modulation in the shape there is a effective change in the electrical properties of CdS nanoflakes. Finally the photocatalytic performance of CdS nanoflakes towards rhodamine b shows greater efficiency than CdS nanoparticles due to high surface area. (C) 2019 Elsevier Ltd. All rights reserved
Interaction of nanoscale damages with static and dynamic contact induced damages in alumina: A novel approach using nanoindentation
No full textThe present work makes novel usage of the well-known nanoindenation (NI) technique to study how the nanohardness (H) and Young's modulus (E) are affected due to variations in the loading rates ranging from 1 to 1000 mN s(-1) for a pressureless sintered alumina of intermediate e.g., 8 mu m grain size and 91% relative density. The same NI technique is also utilized to understand how the presence of microindentation induced radial cracks affect H and E when the nanoindents are at different angular orientations of 0 degrees, 30 degrees, 45 degrees and 90 degrees with respect to the aforesaid radial cracks. Finally, the study is also extended towards using the NI technique to understand how H and E of the same alumina are influenced by the presence of the dynamic contact induced scratch grooves created at normal loads in the range of 2-15 N. Based on the experimentally measured data, extensive usage of Field Emission Scanning Electron Microscopy (FESEM) and stress magnitude estimations; the nature of the deformation and mode of damage interaction evolution are found to be linked to the nanoscale plasticity events related to localized shear stress developed underneath the nanoindenter, the angular orientations of the nanoindents with respect to the direction of propagation of the radial cracks due to statistically induced contact damage, the magnitude and location of residual tensile stresses developed during scratching as well as the spatial density of micro-cracks underneath the scratch grooves. Finally, the implications of the present results in futuristic development of impact damage resistant alumina ceramic are also discussed
Optical Fiber Materials: feature introduction
No full textAn introduction is provided to the feature issue of Optical Materials Express on Optical Fiber Materials. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen