HIV-1 subtype variability and transmitted drug resistance in a culturally diverse population in Western Sydney, New South Wales, Australia.

Background Transmitted human immunodeficiency virus type 1 (HIV-1) drug resistance (TDR) is an important contributor to antiretroviral treatment failure, and is associated with HIV-1 transmission among men who have sex with men (MSM), non-MSM clusters and individuals diagnosed with concurrent sexually transmissible infections (STI). Western Sydney has a culturally diverse population, with a high proportion of non-Australian-born individuals. This study describes the prevalence of TDR and non-B HIV-1 subtypes in a clinic-based population. METHODS: A clinic database was examined for all newly diagnosed treatment-naïve HIV-1 patients and information on their HIV-1 resistance and subtype, demographics including country of birth and diagnosis of a bacterial sexually transmissible infection was collected. RESULTS: Data were available from 74/79 individuals (62 cis-male, 16 cis-female and 1 transgender woman). Of the 74 genotypes, the prevalence of non-B subtypes and TDR was 43/74 (58%; 95%CI = 46.9-69.3) and 14/74 (19%; 95%CI = 10.0 to 27.8). It was also found that 30/79 (38%) had a concurrent bacterial STI. TDR was associated with subtype B infection (OR 3.53; 95%CI = 1.41-8.82; P = 0.007) and being born in Australia (OR 12.0; 95%CI = 2.45-58.86; P = 0.002). CONCLUSION: The relative prevalence of non-B HIV-1 subtypes and TDR is higher in Western Sydney than in the rest of Australia. TDR is associated with subtype B HIV-1 and being Australian born, suggesting ongoing local transmission. This highlights the diversity of the HIV epidemic locally and the need for interventions to prevent ongoing HIV transmission.

Characteristics of pickering emulsion gels formed by droplet bridging.

We experimentally characterize the microstructure and rheology of a carefully designed mixture of immiscible fluids and near-neutral-wetting colloidal particles. Particle bridging across two fluid interfaces provides a route to highly stable gel-like emulsions at volume fractions of the dispersed phase well below the random close-packing limit for spheres. We investigate the microstructural origins of this behavior by confocal microscopy and reveal a percolating network of colloidal particles that serves as a cohesive scaffold, bridging together droplets of the dispersed phase. Remarkably, the mixture's salient rheological characteristics are governed predominantly by the solids loading and can be tailored irrespective of the droplet volume fraction. The identification of this rheological hallmark could provide a means toward the improved design of modern products that utilize solid-stabilized interfaces.

Two-step yielding and directional strain-induced strengthening in dilute colloidal gels.

We investigate the nonlinear rheology of dilute, depletion-induced colloidal gels and report that these systems yield via a two-step process. We propose the two yield points to be associated with interparticle bond rotation and bond breakage, respectively. These distinct yielding mechanisms lead to remarkable creep profiles at intermediate values of the applied stress, highlighted by an anisotropic shear-induced strengthening and flow arrest at very large accumulated strains (γ∼ 80). The possible microstructural origins of this behavior are discussed.

Real-time synthesis of sparsely interconnected neural associative memories.

The problem of implementing associative memories using sparsely interconnected generalized Brain-State-in-a-Box (gBSB) network is addressed in this paper. In particular, a "designer" neural network that synthesizes the associative memories is proposed. An upper bound on the time required for the designer network to reach a solution is determined. A neighborhood criterion with toroidal geometry for the cellular gBSB network is analyzed, in which the number of adjacent cells is independent of the generic cell location. A design method of neural associative memories with prespecified interconnecting weights is presented. The effectiveness of the proposed synthesis method is demonstrated with numerical examples.