3,926 research outputs found

    A complete MacWilliams theorem for convolutional codes

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    © 2014 IEEE. In this paper, we prove a MacWilliams identity for the weight adjacency matrices based on the constraint codes of a convolutional code (CC) and its dual. Our result improves upon a recent result by Gluesing-Luerssen and Schneider, where the requirement of a minimal encoder is assumed. We can also establish the MacWilliams identity for the input-parity weight adjacency matrices of a systematic CC and its dual. Most importantly, we show that a type of Hamming weight enumeration functions of all codewords of a CC can be derived from the weight adjacency matrix, which thus provides a connection between these two very different notions of weight enumeration functions in the convolutional code literature. Finally, the relations between various enumeration functions of a CC and its dual are summarized in a diagram. This explains why no MacWilliams identity exists for the free-distance enumerators

    Vacuum Stability of the wrong sign (ϕ6)(-\phi^{6}) Scalar Field Theory

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    We apply the effective potential method to study the vacuum stability of the bounded from above (ϕ6)(-\phi^{6}) (unstable) quantum field potential. The stability (E/b=0)\partial E/\partial b=0) and the mass renormalization (2E/b2=M2)\partial^{2} E/\partial b^{2}=M^{2}) conditions force the effective potential of this theory to be bounded from below (stable). Since bounded from below potentials are always associated with localized wave functions, the algorithm we use replaces the boundary condition applied to the wave functions in the complex contour method by two stability conditions on the effective potential obtained. To test the validity of our calculations, we show that our variational predictions can reproduce exactly the results in the literature for the PT\mathcal{PT}-symmetric ϕ4\phi^{4} theory. We then extend the applications of the algorithm to the unstudied stability problem of the bounded from above (ϕ6)(-\phi^{6}) scalar field theory where classical analysis prohibits the existence of a stable spectrum. Concerning this, we calculated the effective potential up to first order in the couplings in dd space-time dimensions. We find that a Hermitian effective theory is instable while a non-Hermitian but PT\mathcal{PT}-symmetric effective theory characterized by a pure imaginary vacuum condensate is stable (bounded from below) which is against the classical predictions of the instability of the theory. We assert that the work presented here represents the first calculations that advocates the stability of the (ϕ6)(-\phi^{6}) scalar potential.Comment: 21pages, 12 figures. In this version, we updated the text and added some figure

    An efficient algorithm for optimizing whole genome alignment with noise

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    Motivation: This paper is concerned with algorithms for aligning two whole genomes so as to identify regions that possibly contain conserved genes. Motivated by existing heuristic-based software tools, we initiate the study of an optimization problem that attempts to uncover conserved genes with a global concern. Another interesting feature in our formulation is the tolerance of noise, which also complicates the optimization problem. A brute-force approach takes time exponential in the noise level. Results: We show how an insight into the optimization structure can lead to a drastic improvement in the time and space requirement [precisely, to O(k2n2) and O(k2n), respectively, where n is the size of the input and k is the noise level]. The reduced space requirement allows us to implement the new algorithm, called MaxMinCluster, on a PC. It is exciting to see that when tested with different real data sets, MaxMinCluster consistently uncovers a high percentage of conserved genes that have been published by GenBank. Its performance is indeed favorably compared to MUMmer (perhaps the most popular software tool for uncovering conserved genes in a whole-genome scale). © Oxford University Press 2004; all rights reserved.published_or_final_versio

    Involvement of Matrix Metalloproteinases on the Inhibition of Cells Invasion and Migration by Emodin in Human Neuroblastoma SH-SY5Y Cells

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    [[abstract]]Emodin (1,3,8-trihydroxy-6-methylanthaquinone), an active component present in the root and rhizome of Rheum palmatum L. (Polygonaceae) has anti-bacterial, anti-tumor, diuretic and vasorelaxant effects. However, its mechanism of action on the cell migration and invasion of human neuroblastoma cancer SH-SY5Y cells is not fully understood. In this study, firstly, the effects of emodin on the percentage of viable cells were examined by using MTT assay and it was found that emodin induced dose-and time-dependent inhibition in human neuroblastoma SH-SY5Y cells. Second, the effects of emodin on the migration and invasion of SH-SY5Y cells were examined by using wound assay and matrigel counting and the results showed that emodin suppressed the migration and invasion of SH-SY5Y cells. Third, we examined the effect of emodin on the levels of associated proteins by using Western blotting and the results indicated that emodin inhibited the levels of GRB2, RhoA, HIF-1 alpha, VEGF, FAK, iNOS, COX2, p-p38, p-c-jun, MMP2, MMP9 and MMP7 but promoted the levels of PKC, PI3K, MEKK3 and NF-kappa B p65 that led to the inhibition of migration and invasion of SH-SY5Y cells in vitro

    Gypenosides induced G0/G1 arrest via inhibition of cyclin e and induction of apoptosis via activation of caspases-3 and-9 in human lung cancer A-549 cells

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    [[abstract]]Gynostemma pentaphyllum Makino is known in Asia for its effect on the treatment of hepatitis and cardiovascular diseases. Gypenosides (Gyp) are the major components extracted from Gynostemma pentaphyllum Makino. However, the molecular mechanism underlying the Gyp-induced cell cycle arrest and apoptotic process is unclear. In this study, the chemopreventive role of Gyp in human lung cancer (A549) cells in vitro was evaluated by studying the regulation of the cell cycle and apoptosis. Gyp induced G0/G1 arrest and apoptosis in the human lung cancer A549 cells. Investigation of the cyclin-dependent protein kinase inhibitors by Western blotting showed that p16, p21, p27 and p53 proteins were increased with the increasing time of incubation with. Gyp in the A549 cells. This increase may be the major factor by which Gyp caused G0/G1 arrest in the examined cells. Flow cytometric assay and gel electrophoresis of DNA fragmentation also confirmed that Gyp induced apoptosis in the A549 cells. Our data demonstrated that Gyp-induced apoptotic cell death was accompanied by up-regulation of Bax, caspase-3 and caspase-9, but down-regulation of the Bcl-2 levels. Taken together, Gyp appears to exert its anticancer properties by inducing G0/G1-phase arrest and apoptosis via activation of caspase-3 in human lung A549 cancer cells

    Danthron Induced Apoptosis Through Mitochondria- and Caspase-3-Dependent Pathways in Human Brain Glioblastoma Multiforms GBM 8401 Cells

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    [[abstract]]Danthron (1,8-dihydroxyanthraquinone), is one of component from Rheum palmatum L. (Polygonaceae), has been shown several biological activities but did not show to induce apoptosis in human brain tumor cells. The aim of this study is to investigate the mechanisms by danthron for the induction of apoptotic potential on human brain glioblastoma multiforms GBM 8401 cell line. Danthron showed a marked concentration- and time-dependent inhibition of GBM 8401 cell viability and induced apoptosis in a dose-and time-dependent manner. There was an attenuation of mitochondrial membrane potential (Delta I (m) ) with the alterations of Bcl-2/Bax protein ratio in GBM 8401 cells, indicating the participation of a mitochondria-related mechanism. Pretreatment of a caspase-8 inhibitor (Z-IETD-FMK), caspase-9 inhibitor (Z-LEHD-FMK) and caspase-3 inhibitor (Z-DEVE-FMK) significantly increased the viable of GBM 8401 cells implied that the participations of caspases. Western blotting analysis also showed the activation of initiator caspase-8 and caspase-9, and executor caspase-3 in GBM 8401 cells. Meanwhile, danthron also promoted the generation of reactive oxygen species (ROS) and cytosolic Ca2+ in GBM 8401 cells. Taken together, our data showed that danthron induced apoptosis in GBM 8401 cells through mitochondria-related and caspase-related pathways, and it may be further evaluated as a chemotherapeutic agent for human brain cancer

    Curcumin induces apoptosis through FAS and FADD, in caspase-3-dependent and -independent pathways in the N18 mouse-rat hybrid retina ganglion cells

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    [[abstract]]Curcumin, a naturally occurring yellow pigment isolated from turmeric, is a well known antioxidant with broad spectrum of anti-tumor activities against many human cancer cells. In this study, curcumin-induced cytotoxic effect of mouse-rat hybrid retina ganglion cells (N18) were investigated. For determining cell viability, the trypan blue exclusion and flow cytometric analysis were used. The curcumin-caused cell cycle arrest in N18 cells was examined by flow cytometry. Curcumin affect on the production of reactive oxygen species and Ca2+ and on the decrease of the level of mitochondria membrane potential (Delta Psi(m)) were also examined by flow cytometry. Curcumin-induced apoptosis was determined by DAPI staining and Western blotting was used for examining the apoptotic signaling proteins. Cell cycle analysis showed that G2/M phase arrest and sub-G1 occurs in N18 cells following 48 h exposure to curcumin. Curcumin also caused a marked increase in apoptosis, as characterized by DNA fragmentation (sub-G1 phase formation) and DAPI staining, and dysfunction of mitochondria, which was associated with the activation of caspase-8, -9 and -3. Curcumin also promoted the levels of Fas and FADD, Bax, cytochrome c release, but decreased the levels of Bcl-2 causing changes of Delta Psi(m). Curcumin also induced endoplasmic reticulum stress in N18 cells which was based on the changes of GADD153 and GRP78 and caused Ca2+ release. Curcumin induced apoptosis through the intrinsic pathway and caspase-3-dependent and -independent pathways in N18 cells

    Curcumin-Induced DNA Damage and Inhibited DNA Repair Genes Expressions in Mouse-Rat Hybrid Retina Ganglion Cells (N18)

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    [[abstract]]Curcumin is reported to be a potent inhibitor of the initiation and promotion of many cancer cells. We investigated to examine whether or not curcumin induce DNA damage in mouse-rat hybrid retina ganglion cell line N18 cells. The Comet assay showed that incubation of N18 cells with 10, 25 and 30 mu M of curcumin led to a longer DNA migration smear (Comet tail). The DNA gel electrophoresis showed that 20 mu M of curcumin for 24 and 48 h treatment induced DNA damage and fragments in N18 cells. The real time PCR analysis showed that 20 mu M of curcumin for 48 h treatment decreased ATM, ATR, BRCA1, 14-3-3 sigma, DNA-PK and MGMT mRNA, and ATM and MGMT mRNA expression were inhibited in a time-dependent manner. Our results indicate that curcumin caused DNA damage and inhibited DNA repair genes which may be the factors for curcumin-inhibited cell growth

    The antidiabetic effects of a dry powder of dietary vegetable and fruit mixtures in diabetic db/db mice

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    We evaluated the antidiabetic effects of a mixed vegetable powder-formula I (MVP-FI), which is a dry powder mixture of over 65 kinds of vegetables and fruits, using the db/db type 2 diabetes mouse model. The db/db mice at 8-10 weeks of age were randomly divided into three groups: vehicle treatment, 1.575 g/kg MVP-FI treatment, and 3.15 g/kg MVP-FI treatment. During 12 days of treatment, we measured food intake and body weight changes, fasting blood glucose levels, and plasma lipid levels. Our results showed that the food intake and the body weight of MVP-FI-treated group were decreased gradually. Moreover, the fasting blood glucose level of the treated group was significantly dropped to a normal level comparable to that of the lean mice. Furthermore, we also found that the plasma triglyceride level in the treated group was dropped, whereas the high-density lipoprotein (HDL) level was increased and total cholesterol/HDL-cholesterol ratio was decreased. Taken together, these results suggest that the diabetic conditions of the db/db mice have been improved after 12 days treatment with MVP-FI. The antihyperglycemic and antiobese activities of the MVP-FI, as demonstrated in the present study, may have important clinical implications for improving the management of type 2 diabetic patients. © 2008 Yeung et al, publisher and licensee Dove Medical Press Ltd.published_or_final_versio

    The effect of ex-vivo rotenone intoxication on dopamine re-uptake of LRRK2-R1441G mutant mouse

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