47 research outputs found

    The (k,β„“)(k,\ell)-rainbow index of random graphs

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    A tree in an edge colored graph is said to be a rainbow tree if no two edges on the tree share the same color. Given two positive integers kk, β„“\ell with kβ‰₯3k\geq 3, the \emph{(k,β„“)(k,\ell)-rainbow index} rxk,β„“(G)rx_{k,\ell}(G) of GG is the minimum number of colors needed in an edge-coloring of GG such that for any set SS of kk vertices of GG, there exist β„“\ell internally disjoint rainbow trees connecting SS. This concept was introduced by Chartrand et. al., and there have been very few related results about it. In this paper, We establish a sharp threshold function for rxk,β„“(Gn,p)≀krx_{k,\ell}(G_{n,p})\leq k and rxk,β„“(Gn,M)≀k,rx_{k,\ell}(G_{n,M})\leq k, respectively, where Gn,pG_{n,p} and Gn,MG_{n,M} are the usually defined random graphs.Comment: 7 pages. arXiv admin note: substantial text overlap with arXiv:1212.6845, arXiv:1310.278

    Design and synthesis of non-peptidic thiosemicarbazone derivatives as inhibitors of cathepsins L and K.

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    Cathepsin L, a member of the lysosome cysteine proteases, is ubiquitously expressed in tissue and is responsible for protein turnover. An overexpression of cathepsin L by certain tumor types is associated with enhanced tumor expansion through degradation of the extracellular matrix and the invasion and migration of cancer cells. Therefore, the inhibition of cathepsin L has emerged as a therapeutic strategy against metastatic cancer. Cathepsin K is involved in osteoclastic bone resorption because it is selectively expressed in osteoclasts and is capable of degrading bone matrix. In this project, a small library of thiosemicarbazone derivatives containing thiochromanone, 2,3-dihydroquinoline-4-one, and dibenzoylbenzene scaffolds has been successfully designed and synthesized as potential inhibitors of cathepsin L and other homologous cathepsins (B and K). Through a collaborative study, ten compounds from this library were found to be potent inhibitors (IC50 < 300 nM) of cathepsin L, and nine compounds were potent inhibitors of cathepsin K. None of these inhibitors showed activity against cathepsin B. For example, 6,7-difluorothiochromanone thiosemicarbazone 4 (IC50 = 46 nM) was the most potent inhibitor against cathepsin L from this group, while the 6-trifluoromethyl derivative 28 (IC50 = 21 nM) was the most potent inhibitor against cathepsin K. Structure activity relationship (SAR) studies centered on the thiochromanone thiosemicarbazone scaffold demonstrated that electron-withdrawing functionalities, incorporated primarily at the 6-position of the thiochromanone scaffold, showed good inhibition against cathepsin L in comparison to related analogues bearing electron-donating groups. Collectively, these results expand the known SAR regarding molecular structures and their inhibitory activity against cathepsins L and K.Ph.D

    New skew Laplacian energy of simple digraphs

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    For a simple digraph GG of order nn with vertex setv1,v2,ldots,vn{v_1,v_2,ldots, v_n}, let di+d_i^+ and diβˆ’d_i^- denote theout-degree and in-degree of a vertex viv_i in GG, respectively. LetD+(G)=diag(d1+,d2+,ldots,dn+)D^+(G)=diag(d_1^+,d_2^+,ldots,d_n^+) andDβˆ’(G)=diag(d1βˆ’,d2βˆ’,ldots,dnβˆ’)D^-(G)=diag(d_1^-,d_2^-,ldots,d_n^-). In this paper we introducewidetildeSL(G)=widetildeD(G)βˆ’S(G)widetilde{SL}(G)=widetilde{D}(G)-S(G) to be a new kind of skewLaplacian matrix of GG, where widetildeD(G)=D+(G)βˆ’Dβˆ’(G)widetilde{D}(G)=D^+(G)-D^-(G) andS(G)S(G) is the skew-adjacency matrix of GG, and from which we definethe skew Laplacian energy SLE(G)SLE(G) of GG as the sum of the norms ofall the eigenvalues of widetildeSL(G)widetilde{SL}(G). Some lower and upperbounds of the new skew Laplacian energy are derived and the digraphsattaining these bounds are also determined

    Preparation of the Carbonized Zif&minus;8@PAN Nanofiber Membrane for Cadmium Ion Adsorption

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    The zeolitic imidazolate framework (ZIF&minus;8)@polyacrylonitrile (PAN) nanofiber membrane was prepared and carbonized for heavy metal cadmium ion (Cd2+) adsorption in aqueous medium. Zinc oxide (ZnO) was first sputtered onto the surface of the PAN electrospun nanofiber membrane to provide a metal ion source. Then, the ZIF&minus;8@PAN nanofiber membrane was prepared via in situ solvothermal reaction and carbonized in a tube furnace at 900 &deg;C under a N2 atmosphere to enhance adsorption performance. The synthesized ZIF&minus;8 particles with polyhedral structure were uniformly immobilized on the surface of the PAN electrospun nanofiber membrane. After being heated at 900 &deg;C, the polygonal ZIF&minus;8 shrank, and the carbonized ZIF&minus;8@PAN nanofiber membrane was obtained. Compared with the nanofiber membrane without being carbonized, the adsorption capacity of the carbonized ZIF&minus;8@PAN nanofiber membrane reached 102 mg L&minus;1, and its Cd2+ adsorption efficiency could be more than 90% under the adsorption temperature of 35 &deg;C and solution of pH = 7.5 conditions. According to the adsorption thermodynamics analysis, the Cd2+ adsorption process of the carbonized ZIF&minus;8@PAN nanofiber membrane was spontaneous. The whole Cd2+ adsorption process was more suitably described by the pseudo second-order adsorption kinetics model, indicating that there exists a chemical adsorption mechanism besides physical adsorption

    Oral Administration of a Seed-based Bivalent Rotavirus Vaccine Containing VP6 and NSP4 Induces Specific Immune Responses in Mice

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    Rotavirus is the leading cause of severe diarrheal disease among newborns. Plant-based rotavirus vaccines have been developed in recent years and have been proven to be effective in animal models. In the present study, we report a bivalent vaccine candidate expressing rotavirus subunits VP6 and NSP4 fused with the adjuvant subunit B of E. coli heat-labile enterotoxin (LTB) in maize seeds. The RT-PCR and Western blot results showed that VP6 and LTB-NSP4 antigens were expressed and accumulated in maize seeds. The expression levels were as high as 0.35 and 0.20% of the total soluble protein for VP6 and LTB-NSP4, respectively. Oral administration of transgenic maize seeds successfully stimulated systemic and mucosal responses, with high titers of serum IgG and mucosal IgA antibodies, even after long-term storage. This study is the first to use maize seeds as efficient generators for the development of a bivalent vaccine against rotavirus
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