4,719 research outputs found

    Secure and Robust Image Watermarking Scheme Using Homomorphic Transform, SVD and Arnold Transform in RDWT Domain

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    The main objective for a watermarking technique is to attain imperceptibility, robustness and security against various malicious attacks applied by illicit users. To fulfil these basic requirements for a scheme is a big issue of concern. So, in this paper, a new image watermarking method is proposed which utilizes properties of homomorphic transform, Redundant Discrete Wavelet Transform (RDWT), Arnold Transform (AT) along with Singular Value Decomposition (SVD) to attain these required properties. RDWT is performed on host image to achieve LL subband. This LL subband image is further decomposed into illumination and reflectance components by homomorphic transform. In order to strengthen security of proposed scheme, AT is used to scramble watermark. This scrambled watermark is embedded with Singular Values (SVs) of reflectance component which are obtained by applying SVD to it. Since reflectance component contains important features of image, therefore, embedding of watermark in this part provides excellent imperceptibility. Proposed scheme is comprehensively examined against different attacks like scaling, shearing etc. for its robustness. Comparative study with other prevailing algorithms clearly reveals superiority of proposed scheme in terms of robustness and imperceptibility

    In-vitro Study of Cartilage Differentiation for Enthesis Tissue Engineering

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    Ligaments are a dense connective tissue responsible for joint movements and stability. Anterior Cruciate Ligament (ACL) is one of the four major ligaments of the knee. Being subjected to high physiological loads, ACL is commonly injured,Surgical management with ligament grafts is often required, but these treatments are associated with complications of reduced strength, joint stiffness, repair-rupture. Interface Tissue engineering (ITE) may effectively address these complications where an artificial ligament incorporating the interfacial fibrocartilage can be engineered to provide similar mechanical and functional characteristics as the native tissue. Therefore a multi-compartmental scaffold that can induce the growth and differentiation of fibrocartilage at the interface of engineered bone and ligament tissues would mimic the native structure of bone-ligament –bone block with deposition of appropriate extracellular matrix (ECM) in respective compartments and possession of adequate mechanical properties to support the healing tissue. The current project has focused on the fabrication of a silk-based knitted scaffold which comprises of three compartments, one each for the bone, ligament and enthesis tissues. an array of methods were adopted for surface modification of the compartmentalized knitted silk scaffold by using bio-polymers such as silk solution, chitosan, gelatin and hydroxyapatite on the appropriate compartments. The ligament and bone compartments were reserved for mature cell line culture like MG63 and Saos-2. The various methods used for coatings of polymers over the knitted-silk were alternate soaking, plain coating and freeze-drying. The knitted scaffold was characterized for its water absorption biodegradability,tensile strength, and bio compatibility. Such a complex graft with incorporation of enthesis in laboratory can provide natural insertional strength at the interface and can change the current scenario of replacing injured ligaments

    Preparation of Activated Charcoal and Chromium Removal Using Adsorption

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    High amount of heavy metal ions like chromium (Cr) in the environment has been harmful for animal and human health. If we talk about tannery industries it is quite easily contain chromium in the waste water. So removal of chromium (Cr) from tannery wastes is important need of an hour. Here we used adsorption method for removal and activated charcoal as an adsorbent. The concentration of Cr was determined by atomic absorption spectroscopy (AAS) through absorbance of the solution or sample. Removal of Cr was found to be dependent on pH and maximum adsorption was observed at pH 2.0. Hence, in this study the efficiency of activated charcoal powder to removal Cr from chromium solution is investigated. The results of this study proved that activated charcoal powder can be used to remove chromium (Cr) from tannery effluent

    Evaluation of Controlled Hypotensive Anesthesia in spine surgeries by Comparative Administration of Dexmedetomidine and Nitroglycerine

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    Controlled hypotension or induced hypotension is a technique to reduce the blood loss and the necessity of blood transfusion during surgery by improving the visibility of the surgical site and decreasing the arterial blood pressure until hypotension is reached. Hence based on above findings the present study was planned for Evaluation of Controlled Hypotensive Anesthesia in spine surgeries by Comparative Administration of Dexmedetomidine and Nitroglycerine.The present study was planned in Department of Anaesthesia, Vardhman Institute of Medical Science Pawapuri. Nalanda, Bihar. The study was conducted from November 2015 to December 2016. In the present study total 40 patients were selected undergoing the spine surgeries were evaluated. The cases were divided in two study groups as Group D and Group N. The study drug dexmeditomidine was given to group D in the dose of 1 micro gram/kg body weight in a 600 seconds infusion before induction diluted to 10 ml with normal saline followed by maintenance dose at infusion rate of 0.2 - 0.7 microgm/kg. The group N received 10 ml plain normal saline over 600 seconds before induction The data generated from the present study concludes that Controlled hypotension using dexmeditomidine as bolus dose 1 microgram per kg intravenous over 10 minutes prior to induction followed by continuous intravenous infusion at 0.2 - 0.7 microgram per kg per hour, provided more stable hemodynamics and better surgical field quality compared to nitroglycerine intraoperative infusion at 0.5 to 10 microgram/kg/min

    Solvent Extraction/ion Exchange for Metal Separation and Recovery

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    In the hydrometallurgical processing of complex ores/ concentrates/ secondaries/ wastes, the solutions containing different non-ferrous metals are obtained during leaching the materials in acidic, ammoniacal or alkaline lixiviants. The spent solutions & effluents are also generated in different process industries and contain metallic values. Their discharge in the sewage or river is major concern for environment. In order to meet the strict environmental regulation and conserve the natural resources, metallic values are to be reco-vered. The leach solutions, spent solution and effluents are usually processed to recover metallic values following precipitation, solvent extraction, ion exchange, electrolysis, evaporation, crystallization, electrodialysis etc. Solvent extraction (SX) is one such proven technique in the hydrometallurgical processing for selective extrac-tion and separation of metals due to the ease of applica-bility, versatility and ability to produce high value products. It is used on commercial scale for the recovery of different metals from different solutions viz. copper, nickel, cobalt, zinc, tungsten molybdenum, uranium, rare earths etc. The effluents from waste streams are also processed to recover metals using organic extractants. With the development of improved design of SX equipment and material of construction and newer organic extract-ants, it is possible to recover metals as value added products even from the complex solutions containing various ionic species. The process has been used first time in USA for nuclear application for extraction of uranium from nitrate solution using ether. Subsequently, developments were made for efficient extraction of uranium from other complex solutions
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