90 research outputs found

    Glycan based detection and drug susceptibility of influenza virus

    Get PDF
    ABSTRACT: We have developed a panel of synthetic glycans as receptor mimics for the specific capture of influenza viruses. The glycans were printed onto commercial glass slides using a free amine at the end of a spacer to generate a small focused microarray. The microarray was evaluated for its ability to capture three different strains of influenza A virus, two H1N1, A/Brisbane/59/2007 and A/Solomon Islands/3/2006 and one H3N2, A/Aichi/2/1968. We observed an excellent detection ability with some compounds exhibiting clinically relevant (101 plaque forming units) limit of detection. We also tested the drug susceptibility of current antivirals, Zanamivir and Ostelamivir using this microarray and could determine antiviral resistance for these strains

    Genome amplification and gene expression in the ciliate macronucleus

    Full text link
    The focus of this review is on the micronucleus and macronucleus in the ciliated protozoa and the organization and function of the DNA molecules within them. We present (1) some of the structural and functional differences which are known, (2) the genetic evidence for macronuclear units, (3) two hypotheses for the organization of the DNA molecules in the macronucleus to explain these units, and (4) experiments designed to discriminate between these hypotheses. We conclude that the size of the genome is not reduced in the macronucleus and that there are 45 copies of the haploid genome present in the macronucleus of normal strains of Tetrahymena pyriformis and 800 copies in the macronucleus of Paramecium aurelia . The ciliate genome is relatively simple in terms of repeated sequences. However, not all copies of the genes present in the macronucleus may be identical since fractions of differing thermal stability appear after renaturation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44178/1/10528_2004_Article_BF00486122.pd

    DEFECTS IN IONIC SOLIDS WITH CsCl STRUCTURE

    No full text
    Le calcul des énergies de formation de lacunes isolées dans une famille de cristaux de type CsCl (halogénures de césium, thallium et ammonium) est réexaminé par une approche de minimisation de l'énergie. Un accroissement de la relaxation et une diminution du moment électrique des ions plus proches voisins ont conduit à des valeurs de l'énergie de formation de défaut de Schottky supérieures aux résultats antérieurs (1). La comparaison aux études de conductivité et de diffusion suggère que les propriétés de transport dans les halogénures de césium et de thallium sont dues à un mécanisme lacunaire. Nous avons effectué des mesures de la conductivité électrique et des pertes diélectriques dans des cristaux de NH4Cl dopé par Co++. Les pics de perte diélectrique peuvent être attribués à la réorientation des dipôles impureté interstitielle-lacune. Pour une impureté associée, les fréquences du pic de perte sont déterminées par les sauts de la lacune en premier voisin.The energetics of formation of isolated vacancies in a family of CsCl type crystals (the halides of caesium, thallium and ammonium) are reexamined by using an energy minimisation approach. An increased relaxation and decreased electronic moment of the nearest neighbour ions resulted in overall energy terms leading to values of Schottky defect formation energies which are consistently larger relative to the previous results (1). Comparison with ionic conductivity and diffusion studies suggests that the transport properties in caesium and thallous halides may be understood in terms of Schottky defect mechanisms. We have made measurements on the electrical conductivity and dielectric loss of Co++ doped NH4Cl crystals. The observed dielectric loss peaks can be attributed to the reorientation of interstitial impurity-vacancy type dipoles. For a single bound vacancy the loss peak frequencies are determined by the first neighbour vacancy jumps. These results suggest that a vacancy charge transport mechanism cannot be ruled out in the ammonium halides

    Finite size calculations for point defects

    No full text
    341-344<span style="font-size:14.0pt;line-height: 115%;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" color:black;mso-ansi-language:en-in;mso-fareast-language:en-in;mso-bidi-language:="" hi"="" lang="EN-IN">A method for calculating the defect parameters for point defects in ionic crystals is presented. Defect energies are calculated for finite size crystals and finite size scaling is used to obtain infinite size defect parameters. The method has been demonstrated by using sodium chloride as an example.</span

    Proton exchange mechanism of synthesizing CdS quantum dots in nafion

    No full text
    239-241Nanocrystals of CdS are synthesized in the proton exchange membrane nation in different sizes in the range 1.6 to 6 nm. To understand the process leading to the formation of these quantum dots, we have probed the proton exchange by ac conductance measurements in the frequency range 100 Hz to 13 MHz. Nafion shows good electrical conductivity due to proton transport probably via the Grothus mechanism. Incorporation of cadmium ions by replacement of the hydrogen ions in the sulphonic acid group resulted in a large decrease in conductance indicating the reduction of the mobile carrier density. The conductivity plots all show strong frequency dependence with higher conductance towards the higher frequencies where a near-flat frequency response is seen. After the formation of CdS clusters, there is a partial recovery of conductance corresponding to the reinstatement of the protonic carriers on the side groups. The conductivity of the nation films embedded with the semiconductor quantum dots exhibits a size-dependence with the highest conductivity obtained for the largest clusters. These findings lend clear experimental evidence for the model of synthesis of quantum dots in nafion by the exchange mechanism.</span

    Degenerate four-wave mixing in the carbon cluster C<SUB>60</SUB>

    No full text
    The 60-atom carbon molecule C60 is investigated for its nonlinear optical characteristics by the technique of degenerate four-wave mixing at 532 nm. Very high phase conjugate reflectivities corresponding to a large third order susceptibility &#967;(3)&#8776;10-18 m2V-2 and cubic hyperpolarizability &#947;&#8776;10-41m5V-2 are obtained for C60 solutions in toluene

    Schottky defect enthalpies of alkaline earth oxides

    No full text
    306-312<span style="font-size:14.0pt;line-height: 115%;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" color:black;mso-ansi-language:en-in;mso-fareast-language:en-in;mso-bidi-language:="" hi"="" lang="EN-IN">The Schottky defect formation process in MgO, CaO, SrO, and BaO is investigated using our recently introduced EPPI model3. We find that inclusion of quadrupolar interactions makes a substantial contribution to the formation energy by values ranging from 1.2 eV to 2.9 eV. The EPPI values of the enthalpies (hfs) are 5.9, 5.8, 4.7 and 1.4 eV respectively for MgO, CaO, SrO, and BaO. The results of cation self diffusion experiments in MgO are reanalyzed to include the effects of impurity-vacancy association reaction. The analysis suggests the previous interpretation of the experimental data to be an oversimplification. Since the binding energy of an impurity - defect complex in MgO could be quite large, the effects of the association reaction on the defect densities are appreciable. On the basis of near complete association of the dominant tetravalent cation impurity, hfs in MgO is found to be 5.8 eV which is in good agreement with the theoretical value of the present work.</span
    corecore