1,164 research outputs found

    A Survey on Image Steganography & its Techniques in Spatial & Frequency Domain

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    Steganography is an intelligent art of communicating in a way which hides the endurance of the communication. The image steganography technique takes the asset of confined power of visual system of human being. The art of hiding information such that it averts ferreting out of hidden messages is getting very popular nowadays, which is referred as Steganography. The word Steganography has been educed from the two Greek words - Steganos, which mean covered or secret and Graphy mean writing or drawing. There have been many techniques for hiding information or messages in images in such a manner that the modifications made to the image are perceptually undetected. This paper proposes the evaluation of a few techniques of the Image Steganography in spatial domain and frequency domain. The Image Steganography techniques in spatial domain that would be discussed are Least-Significant-Bit (LSB), LSB Replacement, LSB Matching, and Bit Plane Complexity Segmentation Steganography and frequency domain techniques to be conferred in this paper are Discrete Wavelet Transform (DWT), Discrete Cosine Transform (DCT), Discrete Fourier Transform (DFT) and Singular Valued Decomposition (SVD). Steganography technique is intended to be compared with the Watermarking Technique. DOI: 10.17762/ijritcc2321-8169.15027

    Performance Evaluation of Image Steganography using Hybrid Technique in Frequency Domain

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    Protection of digital multimedia content has become an increasingly important issue for content owners and service providers. The major methodology for protection of some digital content is- Steganography. Image Steganography is a process where information such as name of the creator, status, recipient, etc. is stored in the form of an image which is embedded into the host image in such a way that it will remain invisible or undetectable to a normal person. Only the intended recipient would be able to detect and remove the secret image. There are three main mutually conflicting properties of information hiding schemes: Imperceptibility, Robustness and Capacity. This paper measures the imperceptibility and robustness of the proposed system in terms of two parameters- PSNR and NC respectively. Now, while transmitting the image having some secret information embedded in the cover image, some attacks may arise on it which would degrade the quality of the secret image while extracting it. The technique is again tested against different attacks with varying attack intensities

    Epigastric port site metastasis in an unknown primary: a rare case report

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    OBJECTIVE: The advent of laparoscopic oncologic surgery has brought with it the peculiar issue of port-site metastasis (PSM). The most common source of primary site for PSM is from gall bladder, ovarian and pancreas in which some laparoscopic procedure has been done. PSM in a case of unknown primary is very rare. CASE REPORT: Herein we present a case of a 71-year-old female who had underwent laparoscopic cholecystectomy for cholelithiasis 2 years ago. There was no evidence of malignancy at that time. The patient presented after 2 years of the surgery with a mass at the epigastric port site region which was confirmed to be metastatic adenocarcinoma after histopathology and immunohistochemistry. The site of primary tumor could not be identified even after thorough investigations. RESULTS: The patient underwent wide local excision of the mass followed by adjuvant radiotherapy and chemotherapy for the same. To our knowledge this is the 3rd case reported in literature in which PSM has been found with primary unknown in post cholecystectomy for chronic cholecystitis. CONCLUSIONS: The treating physician should be aware that there is a possibility of development of PSM after a latency period ranging from a few months to years. The most common method to avoid PSM is to prevent intraoperative spillage

    Effect of vitamin D supplementation on blood pressure:a systematic review and meta-analysis incorporating individual patient data

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    D-PRESSURE Collaboration: et al.[Importance]: Low levels of vitamin D are associated with elevated blood pressure (BP) and future cardiovascular events. Whether vitamin D supplementation reduces BP and which patient characteristics predict a response remain unclear.[Objective]: To systematically review whether supplementation with vitamin D or its analogues reduce BP.[Data Sources]: We searched MEDLINE, CINAHL, EMBASE, Cochrane Central Register of Controlled Trials, and http://www.ClinicalTrials.com augmented by a hand search of references from the included articles and previous reviews. Google was searched for gray literature (ie, material not published in recognized scientific journals). No language restrictions were applied. The search period spanned January 1, 1966, through March 31, 2014.[Study Selection]: We included randomized placebo-controlled clinical trials that used vitamin D supplementation for a minimum of 4 weeks for any indication and reported BP data. Studies were included if they used active or inactive forms of vitamin D or vitamin D analogues. Cointerventions were permitted if identical in all treatment arms.[Data Extraction and Synthesis]: We extracted data on baseline demographics, 25-hydroxyvitamin D levels, systolic and diastolic BP (SBP and DBP), and change in BP from baseline to the final follow-up. Individual patient data on age, sex, medication use, diabetes mellitus, baseline and follow-up BP, and 25-hydroxyvitamin D levels were requested from the authors of the included studies. For trial-level data, between-group differences in BP change were combined in a random-effects model. For individual patient data, between-group differences in BP at the final follow up, adjusted for baseline BP, were calculated before combining in a random-effects model.[Main Outcomes and Measures]: Difference in SBP and DBP measured in an office setting.[Results]: We included 46 trials (4541 participants) in the trial-level meta-analysis. Individual patient data were obtained for 27 trials (3092 participants). At the trial level, no effect of vitamin D supplementation was seen on SBP (effect size, 0.0 [95% CI, −0.8 to 0.8] mm Hg; P = .97; I2 = 21%) or DBP (effect size, −0.1 [95% CI, −0.6 to 0.5] mm Hg; P = .84; I2 = 20%). Similar results were found analyzing individual patient data for SBP (effect size, −0.5 [95% CI, −1.3 to 0.4] mm Hg; P = .27; I2 = 0%) and DBP (effect size, 0.2 [95% CI, −0.3 to 0.7] mm Hg; P = .38; I2 = 0%). Subgroup analysis did not reveal any baseline factor predictive of a better response to therapy.[Conclusions and Relevance]: Vitamin D supplementation is ineffective as an agent for lowering BP and thus should not be used as an antihypertensive agent.Peer reviewe

    Nutritional supplements for people being treated for active tuberculosis

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    CITATION: Grobler, L. et al. 2016. Nutritional supplements for people being treated for active tuberculosis. Cochrane Database of Systematic Reviews, 6:CD006086, doi:10.1002/14651858.CD006086.pub4.The original publication is available at https://www.cochranelibrary.comBackground: Tuberculosis and malnutrition are linked in a complex relationship. Tuberculosis may cause undernutrition through increasedmetabolic demands and decreased intake, and nutritional deficiencies may worsen the disease, or delay recovery by depressing important immune functions. At present, there is no evidence-based nutritional guidance for adults and children being treated for tuberculosis. Objectives: To assess the effects of oral nutritional supplements in people being treated with antituberculous drug therapy for active tuberculosis.https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD006086.pub4/fullPublisher's versio

    Off-grid solar photovoltaic systems for rural electrification and emissions mitigation in India

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    Over one billion people lack access to electricity and many of them in rural areas far from existing infrastructure. Off-grid systems can provide an alternative to extending the grid network and using renewable energy, for example solar photovoltaics (PV) and battery storage, can mitigate greenhouse gas emissions from electricity that would otherwise come from fossil fuel sources. This paper presents a model capable of comparing several mature and emerging PV technologies for rural electrification with diesel generation and grid extension for locations in India in terms of both the levelised cost and lifecycle emissions intensity of electricity. The levelised cost of used electricity, ranging from $0.46–1.20/kWh, and greenhouse gas emissions are highly dependent on the PV technology chosen, with battery storage contributing significantly to both metrics. The conditions under which PV and storage becomes more favourable than grid extension are calculated and hybrid systems of PV, storage and diesel generation are evaluated. Analysis of expected price evolutions suggest that the most cost-effective hybrid systems will be dominated by PV generation around 2018

    Microscope 2.0: An Augmented Reality Microscope with Real-time Artificial Intelligence Integration

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    The brightfield microscope is instrumental in the visual examination of both biological and physical samples at sub-millimeter scales. One key clinical application has been in cancer histopathology, where the microscopic assessment of the tissue samples is used for the diagnosis and staging of cancer and thus guides clinical therapy. However, the interpretation of these samples is inherently subjective, resulting in significant diagnostic variability. Moreover, in many regions of the world, access to pathologists is severely limited due to lack of trained personnel. In this regard, Artificial Intelligence (AI) based tools promise to improve the access and quality of healthcare. However, despite significant advances in AI research, integration of these tools into real-world cancer diagnosis workflows remains challenging because of the costs of image digitization and difficulties in deploying AI solutions. Here we propose a cost-effective solution to the integration of AI: the Augmented Reality Microscope (ARM). The ARM overlays AI-based information onto the current view of the sample through the optical pathway in real-time, enabling seamless integration of AI into the regular microscopy workflow. We demonstrate the utility of ARM in the detection of lymph node metastases in breast cancer and the identification of prostate cancer with a latency that supports real-time workflows. We anticipate that ARM will remove barriers towards the use of AI in microscopic analysis and thus improve the accuracy and efficiency of cancer diagnosis. This approach is applicable to other microscopy tasks and AI algorithms in the life sciences and beyond

    Synthetic retinal analogues modify the spectral and kinetic characteristics of microbial rhodopsin optogenetic tools

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    Optogenetic tools have become indispensable in neuroscience to stimulate or inhibit excitable cells by light. Channelrhodopsin-2 (ChR2) variants have been established by mutating the opsin backbone or by mining related algal genomes. As an alternative strategy, we surveyed synthetic retinal analogues combined with microbial rhodopsins for functional and spectral properties, capitalizing on assays in C. elegans, HEK cells and larval Drosophila. Compared with all-trans retinal (ATR), Dimethylamino-retinal (DMAR) shifts the action spectra maxima of ChR2 variants H134R and H134R/T159C from 480 to 520 nm. Moreover, DMAR decelerates the photocycle of ChR2(H134R) and (H134R/T159C), thereby reducing the light intensity required for persistent channel activation. In hyperpolarizing archaerhodopsin-3 and Mac, naphthyl-retinal and thiophene-retinal support activity alike ATR, yet at altered peak wavelengths. Our experiments enable applications of retinal analogues in colour tuning and altering photocycle characteristics of optogenetic tools, thereby increasing the operational light sensitivity of existing cell lines or transgenic animals

    Synthetic retinal analogues modify the spectral and kinetic characteristics of microbial rhodopsin optogenetic tools

    Get PDF
    Optogenetic tools have become indispensable in neuroscience to stimulate or inhibit excitable cells by light. Channelrhodopsin-2 (ChR2) variants have been established by mutating the opsin backbone or by mining related algal genomes. As an alternative strategy, we surveyed synthetic retinal analogues combined with microbial rhodopsins for functional and spectral properties, capitalizing on assays in C. elegans, HEK cells and larval Drosophila. Compared with all-trans retinal (ATR), Dimethylamino-retinal (DMAR) shifts the action spectra maxima of ChR2 variants H134R and H134R/T159C from 480 to 520 nm. Moreover, DMAR decelerates the photocycle of ChR2(H134R) and (H134R/T159C), thereby reducing the light intensity required for persistent channel activation. In hyperpolarizing archaerhodopsin-3 and Mac, naphthyl-retinal and thiophene-retinal support activity alike ATR, yet at altered peak wavelengths. Our experiments enable applications of retinal analogues in colour tuning and altering photocycle characteristics of optogenetic tools, thereby increasing the operational light sensitivity of existing cell lines or transgenic animals
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