Browsing by Subject "Adsorption"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Open Access
    Broadly neutralizing antibody responses in a large longitudinal sub-Saharan HIV primary infection cohort
    (Public Library of Science, 2016) Landais, Elise; Huang, Xiayu; Havenar-Daughton, Colin; Murrell, Ben; Price, Matt A; Wickramasinghe, Lalinda; Ramos, Alejandra; Bian, Charoan B; Simek, Melissa; Allen, Susan; Karita, Etienne; Kilembe, William; Lakhi, Shabir; Inambao, Mubiana; Kamali, Anatoli; Sanders, Eduard J; Anzala, Omu; Edward, Vinodh; Bekker, Linda-Gail; Tang, Jianming; Gilmour, Jill; Kosakovsky-Pond, Sergei L; Phung, Pham; Wrin, Terri; Crotty, Shane; Godzik, Adam; Poignard, Pascal
    Author Summary Understanding how HIV-1-broadly neutralizing antibodies (bnAbs) develop during natural infection is essential to the design of an efficient HIV vaccine. We studied kinetics and correlates of neutralization breadth in a large sub-Saharan African longitudinal cohort of 439 participants with primary HIV-1 infection. Broadly nAb responses developed in 15% of individuals, on average three years after infection. Broad neutralization was associated with high viral load, low CD4+ T cell counts, virus subtype C infection and HLA*A3(-) genotype. A correlation with high overall plasma IgG levels and anti-Env binding titers was also found. Specificity mapping of the bnAb responses showed that glycan-dependent epitopes, in particular the N332 region, were most commonly targeted, in contrast to other bnAb epitopes, suggesting that the HIV Env N332-glycan epitope region may be a favorable target for vaccine design.
  • Thumbnail Image
    Item
    Restricted
    The chemical vapour and liquid deposition of tetraethoxysilane on the external surface of ZSM-5
    (Elsevier, 1998) Weber, R W; Möller, K P; Unger, M; O'Connor, C
    The external acidity of ZSM-5 was modified by chemical vapour deposition (CVD) and chemical liquid deposition (CLD) of tetraethoxysilane [Si(OC2 H5 ) 4 ] using a static vacuum system, a vapour phase flow system and liquid phase deposition. Temperature programmed desorption (TPD) techniques were used to characterise the acidity changes arising from these modifications. Pyridine was used as a probe for the total acidity and 4-methyl quinoline (MQ) was used to probe the external acidity. The adsorption capacities of the samples were measured using n-hexane, p-xylene, o-xylene and 1,2,4-trimethyl benzene. The extent of Si(OC2 H5 ) 4 deposition was strongly dependent on temperature in both vapour phase flow and static vacuum systems. Continuous Si(OC2 H5 ) 4 deposition was observed in the presence of H2 O at relatively high temperatures when decomposition products were removed from the sample. It is proposed that physisorbed species need to be removed by evacuation or calcination to re-expose active sites, thereby enabling complete inertisation of the external surface acidity to occur, and that a more uniform covering can be obtained when a gradual deposition process is used. Such a process may be achieved by the use of diluents or by preventing overexposure of Si(OC2 H5 ) 4 to the sample under conditions where continuous deposition may occur. It was shown that it is possible to reduce the relative external surface acidity by 97% without significant changes in acidity as measured by Py-TPD or adsorption capacity.