154 research outputs found

    Implementation of cryptographic algorithms and protocols

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    The purpose of the project is to provide a practical survey of both the principles and practice of cryptography. Cryptography has become an essential tool in transmission of information. Cryptography is the central part of several fields: information security and related issues, particularly, authentication, and access control. Cryptography encompasses a large number of algorithms which are used in building secure applications

    A Prospective Randomized Controlled study comparing Anaesthetic Efficacy of Intrathecal Isobaric 0.5% Levobupivacaine with Intrathecal Isobaric 0.75% Ropivacaine for Lower Abdominal and Lower Limb Orthopaedic Surgeries.

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    INTRODUCTION: Ropivacaine and levobupivacaine are the recent local anesthetic drugs that have significantly lower cardiotoxicity compared to bupivacaine. We aimed to compare the anaesthetic efficacy of these drugs via intrathecal route. METHODS: 60 patients planned for lower abdominal and lower limb orthopaedic surgeries were included in this randomized controlled study. They were divided into two groups to receive either 22.5mg of 0.75%ropivacaine or 15mg of 0.5%levobupivacaine intrathecally. Time of onset of sensory and motor block as well as of maximum sensory and motor blocks, duration of the blocks, hemodynamic parameters and adverse effects were assessed. Results were analysed statistically. RESULTS: The sensory block at level of T10 occurred earlier with levobupivacaine compared to ropivacaine.(p=0.009). Also, the maximum sensory block was attained much faster in levobupivacaine group compared to ropivacaine group.(p=0.036).The mean time of onset of sensory block at T10 and maximal sensory block were 6.8±4.715 and 10.43±4.854 minutes in ropivacaine group and 4.1±2.636 and 7.9±4.245 minutes in levobupivacaine group respectively. Hemodynamic parameters, adverse effects, duration of sensory and motor blocks and onset of motor block were comparable in the two groups. CONCLUSION: The present study concludes that both intrathecal isobaric 0.75% ropivacaine and 0.5% levobupivacaine possess similar block characteristics except difference in their onset time for sensory block which was significantly shorter with levobupivacaine compared to ropivacaine. Further, both the drugs produce similar hemodynamic effects with very less adverse effects

    Parameterized Complexity of Biclique Contraction and Balanced Biclique Contraction

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    In this work, we initiate the complexity study of Biclique Contraction and Balanced Biclique Contraction. In these problems, given as input a graph G and an integer k, the objective is to determine whether one can contract at most k edges in G to obtain a biclique and a balanced biclique, respectively. We first prove that these problems are NP-complete even when the input graph is bipartite. Next, we study the parameterized complexity of these problems and show that they admit single exponential-time FPT algorithms when parameterized by the number k of edge contractions. Then, we show that Balanced Biclique Contraction admits a quadratic vertex kernel while Biclique Contraction does not admit any polynomial compression (or kernel) under standard complexity-theoretic assumptions

    Vitamin D Status of Older Adults of Diverse Ancestry Living in the Greater Toronto Area

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    Background: Physiological and lifestyle factors put older adults at an increased risk of vitamin D insufficiency and resulting negative health outcomes. Here we explore the vitamin D status in a sample of community dwelling older adults of diverse ancestry living in the Greater Toronto area (GTA). Methods: Two hundred and twenty-four (224) adults over 60 years of age were recruited from the Square One Older Adult Centre, in Mississauga, Ontario. Circulating 25-hydroxyvitamin D (25(OH)D) concentrations were measured from dried blood spot cards. Dietary and supplemental intakes of vitamin D were assessed via questionnaires. Skin pigmentation was assessed quantitatively by measuring melanin levels using a reflectometer. Results: The mean 25(OH)D concentration in the total sample was 82.4 nmol/L. There were no statistically significant differences in serum 25(OH)D concentrations, supplemental or dietary vitamin D intakes between the three major ancestral groups (East Asians, Europeans and South Asians). Females had significantly higher 25(OH)D concentrations than males (84.5 nmol/L vs. 72.2 nmol/L, p = 0.012). The proportion of participants with 25(OH)D concentrations below 50 nmol/L and 75 nmol/L were 12.1%, and 38.8%, respectively. The mean daily supplemental intake of vitamin D was 917 IU/day. Vitamin D intake from supplements was the major factor determining 25(OH)D concentrations (p \u3c 0.001). Conclusions: Mean concentration of 25(OH)D in a sample of older adults of diverse ancestry living in the GTA exceeded 80 nmol/L, and there were no significant differences in 25(OH)D levels between ancestral groups. These results sharply contrast with our recent study focused on young adults of diverse ancestry living in the same geographic area, in which we found substantially lower 25(OH)D concentrations (mean 39.5 nmol/L), low supplemental vitamin D intake (114 IU/day), and significant differences in 25(OH)D levels between ancestral groups. High daily intake of supplemental vitamin D in this sample of older adults likely accounts for such disparate findings with respect to the young adult sample

    A Microsatellite Guided Insight into the Genetic Status of Adi, an Isolated Hunting-Gathering Tribe of Northeast India

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    Tibeto-Burman populations of India provide an insight into the peopling of India and aid in understanding their genetic relationship with populations of East, South and Southeast Asia. The study investigates the genetic status of one such Tibeto-Burman group, Adi of Arunachal Pradesh based on 15 autosomal microsatellite markers. Further the study examines, based on 9 common microsatellite loci, the genetic relationship of Adi with 16 other Tibeto-Burman speakers of India and 28 neighboring populations of East and Southeast Asia. Overall, the results support the recent formation of the Adi sub-tribes from a putative ancestral group and reveal that geographic contiguity is a major influencing factor of the genetic affinity among the Tibeto-Burman populations of India

    Inhibition of COX-2 in Colon Cancer Modulates Tumor Growth and MDR-1 Expression to Enhance Tumor Regression in Therapy-Refractory Cancers In Vivo

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    AbstractHigher cyclooxygenase 2 (COX-2) expression is often observed in aggressive colorectal cancers (CRCs). Here, we attempt to examine the association between COX-2 expression in therapy-refractory CRC, how it affects chemosensitivity, and whether, in primary tumors, it is predictive of clinical outcomes. Our results revealed higher COX-2 expression in chemoresistant CRC cells and tumor xenografts. In vitro, the combination of either aspirin or celecoxib with 5-fluorouracil (5-FU) was capable of improving chemosensitivity in chemorefractory CRC cells, but a synergistic effect with 5-FU could only be demonstrated with celecoxib. To examine the potential clinical significance of these observations, in vivo studies were undertaken, which also showed that the greatest tumor regression was achieved in chemoresistant xenografts after chemotherapy in combination with celecoxib, but not aspirin. We also noted that these chemoresistant tumors with higher COX-2 expression had a more aggressive growth rate. Given the dramatic response to a combination of celecoxib + 5-FU, the possibility that celecoxib may modulate chemosensitivity as a result of its ability to inhibit MDR-1 was examined. In addition, assessment of a tissue microarray consisting of 130 cases of CRCs revealed that, in humans, higher COX-2 expression was associated with poorer survival with a 68% increased risk of mortality, indicating that COX-2 expression is a marker of poor clinical outcome. The findings of this study point to a potential benefit of combining COX-2 inhibitors with current regimens to achieve better response in the treatment of therapy-refractory CRC and in using COX-2 expression as a prognostic marker to help identify individuals who would benefit the greatest from closer follow-up and more aggressive therapy
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