Synthesis and structure of undoped and indium-doped thermoelectric lead telluride nanoparticles

Undoped and indium (In)-doped lead telluride (PbTe) nanostructures were synthesized via solvothermal/hydrothermal route. The crystalline structure of the as-prepared undoped and In-doped PbTe samples was examined by X-ray diffraction (XRD) which indicated the formation of face-centered single-phase cubic crystal. A first principle calculation on indium doping shows that the indium atoms are more likely to replace lead (Pb) rather than to take the interstitial sites. Laser-induced breakdown spectroscopy (LIBS) analysis confirms that indium is incorporated into the PbTe matrix of the indium-doped PbTe samples. The effects of surfactant and synthesis temperature on the structure and morphology of the undoped PbTe were also investigated; it was found that PbTe nanostructures synthesized with the addition of surfactants exhibited uniform shapes and their size increased with the synthesis temperature.     

Performance Analysis of all Optical 4*2 and 8*3 Encoder Using Two Dimensional Photonic Crystals Waveguides

Silicon - In this paper, Two Dimensional Photonic Crystal (2DPC) based 4*2 and 8*3 encoders are devised using Y shaped waveguides. The proposed encoder operates at 1550 nm. In this...     

Red lesion in fundus image with hexagonal pattern feature and two-level segmentation

Multimedia Tools and Applications - Red lesion identification at its early stage is very essential for the treatment of diabetic retinopathy to prevent loss of vision. This work proposes a red...     

Phototherapeutic keratectomy versus alcohol epitheliectomy with mechanical debridement for superficial variant of granular dystrophy: A paired eye comparison

PurposeTo compare outcome of phototherapeutic keratectomy (PTK) and alcohol epitheliectomy with mechanical debridement for superficial variant of granular dystrophy.MethodCase report. A 7 year old girl with superficial variant of granular dystrophy with an visual acuity of 20/70 both eyes, underwent a simultaneous PTK in right eye (OD) and alcohol epitheliectomy with mechanical debridement in left eye (OS). Post operatively the visual acuity, refraction and corneal clarity were assessed.ResultsOn the first post-operative day uncorrected visual acuity was 20/50 in both eyes. At 2 weeks, vision improved to 20/40 with +2.50 ?2.00 × 180 in OD and +1.50 ?1.50 × 180 in OS. At 2 years, vision and refraction were 20/25 with +2.50 ?2.00 × 180 in OD and 20/25 with +1.25 ?1.50 × 170 OS respectively. There was early recurrence of the granular dystrophy.ConclusionThe visual outcomes of both PTK and alcohol epitheliectomy are similar for superficial variant of granular dystrophy. The hyperopic shift with PTK is a matter of concern. Alcohol epitheliectomy can be used in treatment of superficial corneal dystrophies where PTK is unavailable.     

Dynamics of nanotechnology patenting: An Indian scenario

Nanotechnology reflects the combination/interaction of knowledge which is interdisciplinary in nature. Exclusive monopoly over patents on nano-scale materials, devices and processes is a much sought after concept among technology based industries today. According to many scientists and theorists, this science can lead to solutions of some of the toughest problems faced by mankind and the list of patents on nano-scale materials, tools and processes is expanding at a phenomenal pace. Even India is among the top 20 nations in nanotechnology research as is evident by the number of patents filed each year. Trade regime of the world has brought into focus the ability to generate and secure IPR. The transformation has been rapid and in such a dynamic landscape it is vital to protect the intellectual property. With increasing private sector involvement in nanotechnology R&D, the need for a comprehensive framework for regulating nanotechnology IPRs will be pivotal to the commercial success of the technology. Hence, it becomes increasingly more and more important to learn the various issues in patenting of nanotechnology inventions and address these issues now so as to avoid any problems later. This paper discusses the various methodologies used in the developing countries and what can be done in India to protect the same keeping in mind the interests of various partners in the value chain of nanotech patent from lab to market.     

Cytotoxic and antitumour principles from Ixora coccinea flowers

Susceptibility of four major rat tissues to oxidative damage in terms of lipid peroxidation induced by in vitro by ascorbate-Fe2+ in homogenates and mitochondria has been examined. Lipid peroxidation, as assessed by thiobarbituric acid reactive substances (TBARS) and conjugated dienes was maximum in brain followed by liver, kidney and heart. However, the time course of lipid peroxidation showed different patterns in tissues examined. The higher susceptibilities of brain and liver can be explained by substrate availability and to a lesser extent the level of antioxidants. The differences observed in the tissues studied may reflect their susceptibility to degenerative diseases and xenobiotic toxicity which are considered as a result of oxidative damage to membranes.     

Experimental and Theoretical Investigations on Geocell-Supported Embankments

This paper studies the advantages of geocell reinforcement on the performance of earth embankments constructed over weak foundation soil through laboratory model tests and proposes a simple method for the design of geocell-supported embankments. Model embankments were constructed above a layer of geocells formed using geogrids on top of a soft clay bed prepared in a steel test tank. Uniform surcharge pressure was applied on the crest and pressure-deformation behavior of the embankment and strains in the walls of geocells were monitored continuously until the failure was reached. The influence on the behavior of the embankment of various parameters—like tensile stiffness of geocell material, height and length of geocell layer, pocket-size of the cell, pattern of formation of geocells, and type of fill material inside the cells—was studied. Geocell reinforcement was found to be advantageous in increasing the load-bearing capacity and reducing the deformations of the embankments. The experimental results were validated using a general purpose slope-stability program and a design procedure useful for the preliminary design of geocell-supported embankments is illustrated.     

Versatility of superaustenitic stainless steels in marine applications

Corrosion of construction materials in marine applications is a major problem. The frequent variations in chloride ion concentration and temperature experienced by a system pose a serious threat. This investigation evaluated the performance of superaustenitic stainless steels in marine applications by potentiodynamic anodic polarization studies. The concentrations of metal ions such as iron, chromium, and nickel at different impressed potentials were analyzed by inductively coupled plasma spectrometry, which revealed little tendency for leaching of metal ions.