68 research outputs found

    Direct observation of large temperature fluctuations during DNA thermal denaturation

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    In this paper we report direct measurement of large low frequency temperature fluctuations in double stranded (ds) DNA when it undergoes thermal denaturation transition. The fluctuation, which occurs only in the temperature range where the denaturation occurs, is several orders more than the expected equilibrium fluctuation. It is absent in single stranded (ss) DNA of the same sequence. The fluctuation at a given temperature also depends on the wait time and vanishes in a scale of few hours. It is suggested that the large fluctuation occurs due to coexisting denaturated and closed base pairs that are in dynamic equilibrium due to transition through a potential barrier in the scale of 25-30k_{B}T_{0}(T_{0}=300K).Comment: 4 pages, 5 figures, Replaced with revised versio

    In Silico Analysis To Explore Novel Inhibitors For Human Proto-oncogene Tyrosine Protein Kinase Src

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    The first oncogene and the first non receptor tyrosine kinase, Src, plays a key role in cell morphology, motility, proliferation and survival. Over expression of Src kinase activity disrupts the RAS pathway in signaling pathway, where it loses its ability to hydrolyse GTP and thus, leads to cancer. A wide range of evidences indicated that Src-signaling was important in the oncogenesis of prostate cancer and other tumours. Src-signaling is involved in androgen-induced proliferation of prostate cancer in cancer tissue of patients having castration-refractory prostate cancer. Once prostate cancer becomes castration-resistant, bone metastases become significant problem for which treatment options are limited. As Src is involved in multiple signaling pathways, central to prostate cancer development, progression, and metastasis, in addition to normal and pathologic osteoclast activities, Src inhibition becomes a valid therapeutic strategy for investigation. Existing Src kinase inhibitors are less efficient towards prostate cancer and bone metastasis. Hence an in silico work was carried out to identify novel potent inhibitors. Three published inhibitors of human Src kinase those are currently under clinical trial such as AZDO530, bosutinib and dasatinib were subjected to high-throughput screening from more than million entries of Ligand.Info Meta-Database, based on the assumption that small molecules with similar structure have similar pharmacological properties. The ligand dataset of 1152 generated through this approach were prepared using LigPrep to generate possible conformations of each ligand molecule, and at the same time duplicate conformers, conformations with reactive functional group and ADME violaters were rejected. The human Src kinase co-crystal structure with AZDO530 was analyzed to find the inhibitor binding site. The crystal structure was optimized and energy was minimized applying OPLS force field in Maestro v9.0. Glide 5.5 docking was performed to predict the binding orientation of prepared ligand molecule into a grid of 20 x 20 x 20 Å created around the centroid of optimized human Src kinase. Ten lead molecules with good binding affinity with human Src were identified. In silico pharmacokinetics study for these ten lead molecules had shown no ADME violation. Analysis of Lead ‘1’ - human Src docking complex had revealed a XP Gscore of -11.56 kcal/mol with highly stabilized hydrogen bond network with Ala390, Asn391, Lys295, W543 and W640 and good Van der Waals interactions. The docking complex coincides well with the native co-crystallized human Sac and inhibitor AZDO530 complex. Thus, Fisetin, identified as Lead ‘1’ in the present study would be highly useful for developing potential drug molecules for treatment of advanced prostate cancer

    A NOVEL FACE DETECTION AND TRACKING ALGORITHM IN REAL- TIME VIDEO SEQUENCES

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    Face detection is a image processing technology that determines the location and size of human faces in digital images or video. This module precedes face recognition systems that plays an important role in applications such as video surveillance, human computer interaction and so on. This proposed work focuses mainly on multiple face detection technique, taking into account the variations in digital images or video such as face pose, appearances and illumination. The work is based on skin color model in YCbCr and HSV color space. First stage of this proposed method is to develop a skin color model and then applying the skin color segmentation in order to specify all skin regions in an image. Secondly, a template matching is done to assure that the segmented image does not contain any non-facial part. This algorithm works to be robust and efficient

    Interlayer Registry Determines the Sliding Potential of Layered Metal Dichalcogenides: The case of 2H-MoS2

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    We provide a simple and intuitive explanation for the interlayer sliding energy landscape of metal dichalcogenides. Based on the recently introduced registry index (RI) concept, we define a purely geometrical parameter which quantifies the degree of interlayer commensurability in the layered phase of molybdenum disulphide (2HMoS2). A direct relation between the sliding energy landscape and the corresponding interlayer registry surface of 2H-MoS2 is discovered thus marking the registry index as a computationally efficient means for studying the tribology of complex nanoscale material interfaces in the wearless friction regime.Comment: 13 pages, 7 figure

    Quantifying the Stacking Registry Matching in Layered Materials

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    A detailed account of a recently developed method [Marom et al., Phys. Rev. Lett. 105, 046801 (2010)] to quantify the registry mismatch in layered materials is presented. The registry index, which was originally defined for planar hexagonal boron-nitride, is extended to treat graphitic systems and generalized to describe multi-layered nanotubes. It is shown that using simple geometric considerations it is possible to capture the complex physical features of interlayer sliding in layered materials. The intuitive nature of the presented model and the efficiency of the related computations suggest that the method can be used as a powerful characterization tool for interlayer interactions in complex layered systems.Comment: 8 pages, 8 figures. To be published in a special issue of the Israel Journal of Chemistry regarding "Inorganic Nanotubes and Nanostructures

    Taking reincarnation seriously: Critical discussion of some central ideas from John Hick

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    Reincarnation has not been entirely neglected in the philosophy of religion but it has not always been taken seriously or carefully discussed in relation to its role in believers’ lives. John Hick is exceptional insofar as he gave sustained attention to the belief, at least as it features in the philosophies of Vedānta and Buddhism. While acknowledging the value of Hick’s recognition of the variety of reincarnation beliefs, this article critically engages with certain aspects of his approach. It argues that Hick’s search for a ‘criterion’ of reincarnation is misguided, and that his distinction between ‘factual’ and ‘mythic’ forms of the doctrine is over-simplifying

    Karma, morality, and evil

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    The doctrine of karma has been praised as a rational and morally edifying explanatory response to the existence of evil and apparent injustice in the world. Critics have attacked it as a morally misguided dogma that distorts one's vision of reality. This essay, after outlining the traditional doctrine, examines three criticisms that have been central to recent debates: firstly, that the doctrine offers no practical guidance; second, that it faces a dilemma between free will and fatalism; and third, that it involves a morally repugnant form of blaming victims for their own misfortunes. Possible responses are considered, the depth of the disagreement is highlighted, and a morally significant difference between alternative ways of articulating the belief in karma is analyzed

    Electromechanical properties of suspended Graphene Nanoribbons

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    Graphene nanoribbons present diverse electronic properties ranging from semiconducting to half-metallic, depending on their geometry, dimensions and chemical composition. Here we present a route to control these properties via externally applied mechanical deformations. Using state-of-the-art density functional theory calculations combined with classical elasticity theory considerations, we find a remarkable Young's modulus value of ~7 TPa for ultra-narrow graphene strips and a pronounced electromechanical response towards bending and torsional deformations. Given the current advances in the synthesis of nanoscale graphene derivatives, our predictions can be experimentally verified opening the way to the design and fabrication of miniature electromechanical sensors and devices based on ultra-narrow graphene nanoribbons.Comment: 12 pages, 6 figure
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