We show that the number of non-trivial rational points of height at most B, which lie on the cubic surface x1x2x3 = x4(x1 + x2 + x3) , has order of magnitude B(log B). This agrees with Manin’s conjecture.

It is shown that any triangular derivation on k[X1, X2, X3, X4] sending Xi to a monomial has kernel generated by at most four elements, hence is finitely generated. An explicit formula for the generators is given.

We coinfected rhesus macaques with CXC chemokine receptor 4- and CC chemokine receptor 5-specific simian/human immunodeficiency viruses (SHIVs) to elucidate the basis for the early dominance of R5-tropic strains seen in HIV-infected humans. We found no intrinsic barrier to the transmission and dissemination of high-dose X4-SHIV in the dually infected macaques. In animals that maintained a viral...

Dendritic cells (DCs) are essential antigen-presenting cells for the induction of T cell immunity against HIV. On the other hand, due to the susceptibility of DCs to HIV infection, virus replication is strongly enhanced in DC-T cell interaction via an immunological synapse formed during the antigen presentation process. When HIV-1 is isolated from individuals newly infected with the mixture of ...

In the present study we demonstrate that both X4- and R5-tropic HIV-1 strains are able to infect the human epithelial cell line HT-29. Infection was enhanced 2-fold when HIV was added to semen before contact with the cell cultures. The enhancing effect of semen was complement dependent, as evidenced by blockage of generation of C3a/C3a(desArg) in semen by heat or EDTA treatment of semen and sup...

BACKGROUND The prevalence and correlates of CXCR4-use in recently diagnosed patients and the impact of X4/DM transmission remain largely unknown. METHOD Genotypic coreceptor use determination on the baseline sample of 539 recently diagnosed individuals. Correlation of coreceptor use with clinical, viral and epidemiological data and with information on transmission events as obtained through p...

Vpr is an HIV-1 accessory protein that plays numerous roles during viral replication, and some of which are cell type dependent. To test the hypothesis that HIV-1 tropism extends beyond the envelope into the vpr gene, studies were performed to identify the associations between coreceptor usage and Vpr variation in HIV-1-infected patients. Colinear HIV-1 Env-V3 and Vpr amino acid sequences were ...

BACKGROUND Understanding co-receptor tropism of HIV-1 strains circulating in India will provide key analytical leverage for assessing the potential usefulness of newer antiretroviral drugs such as chemokine co-receptor antagonists among Indian HIV-infected populations. The objective of this study was to determine using in silico methods, HIV-1 tropism among a large number of Indian isolates bot...

An octagon quadrangle is the graph consisting of an 8-cycle (x1, ..., x8) with two additional chords: the edges {x1, x4} and {x5, x8}. An octagon quadrangle system of order v and index λ [OQS] is a pair (X,B), where X is a finite set of v vertices and B is a collection of edge disjoint octagon quadrangles (called blocks) which partition the edge set of λKv defined on X. A 4-kite is the graph ha...

Tujuan penelitian ini adalah untuk mengetahui dan menganalisis kualitas pelayanan dari dimensi yaitu tangibles (bukti langsung), reliability (keandalan), responsiveness (daya tanggap), assurance (jaminan) secara parsial atau simultan yang paling dominan. Sampel digunakan dalam berjumlah 98 responden. Metode pengambilan sampel dengan menggunakan accidental sampling. Pengumpulan data kuesioner. a...