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We explore the vapor-liquid phase behavior of binary mixtures of Lennard-Jones-type molecules where one component is supercritical, given the system temperature. We apply the self-consistency approach to the Ornstein–Zernike integral equations to obtain the correlation functions. The consistency checks include not only thermodynamic consistencies (pressure consistency and Gibbs–Duhem consistency), but also pointwise consistencies, such as the zero-separation theorems on the cavity functions. The consistencies are enforced via the bridge functions in the closure which contain adjustable parameters. The full solution requires the values of not only the monomer chemical potentials, but also the dimer chemical potentials present in the zero-separation theorems. These are evaluated by the direct chemical-potential formula [L. L. Lee, J. Chem. Phys. 97, 8606 (1992)] that does not require temperature nor density integration. In order to assess the integral equation accuracy, molecular-dynamics simulations are carried out alongside the states studied. The integral equation results compare well with simulation data. In phase calculations, it is important to have pressure consistency and valid chemical potentials, since the matching of phase boundaries requires the equality of the pressures and chemical potentials of both the liquid and vapor phases. The mixtures studied are methane-type and pentane-type molecules, both characterized by effective Lennard-Jones potentials. Calculations on one isotherm show that the integral equation approach yields valid answers as compared with the experimental data of Sage and Lacey. To study vapor-liquid phase behavior, it is necessary to use consistent theories; any inconsistencies, especially in pressure, will vitiate the phase boundary calculations. [ABSTRACT FROM AUTHOR]

Small interfering RNAs (siRNAs) directed against proinflammatory cytokines have the potential to treat numerous diseases associated with intestinal inflammation; however, the side-effects caused by the systemic depletion of cytokines demands that the delivery of cytokine-targeted siRNAs be localized to diseased intestinal tissues. Although various delivery vehicles have been developed to orally deliver therapeutics to intestinal tissue, none of these strategies has demonstrated the ability to protect siRNA from the harsh environment of the gastrointestinal tract and target its delivery to inflamed intestinal tissue. Here, we present a delivery vehicle for siRNA, termed thioketal nanoparticles (TKNs), that can localize orally delivered siRNA to sites of intestinal inflammation, and thus inhibit gene expression in inflamed intestinal tissue. TKNs are formulated from a polymer, poly-(1,4-phenyleneacetone dimethylene thioketal), that degrades selectively in response to reactive oxygen species (ROS). Therefore, when delivered orally, TKNs release siRNA in response to the abnormally high levels of ROS specific to sites of intestinal inflammation. Using a murine model of ulcerative colitis, we demonstrate that orally administered TKNs loaded with siRNA against the proinflammatory cytokine tumour necrosis factor-alpha (TNF-α) diminish TNF-α messenger RNA levels in the colon and protect mice from ulcerative colitis. [ABSTRACT FROM AUTHOR]

A study of drug use locations in Hartford, CT, is designed to understand the environmental and social conditions within "high risk sites" where drug users inject drugs or smoke crack, in order to develop AIDS prevention models that build upon the physical and social organization of these locations. The study assesses high-risk sites characterized on the basis of type of location or structure, presence and strength of gatekeepers, and presence and strength of HIV prevention opportunities and pressures. A combination of ethnographic, epidemiological, and social network methods are used to document the characteristics, social organization, natural history, and dynamics of these sites, the network relations of site users, and the various opportunities for, or barriers to, on-site social-level HIV prevention intervention. This paper provides an overview of the study and presents preliminary findings, including the degree to which drug injectors and crack smokers use specific types of sites in Hartford. The paper also discusses the ways these findings inform development of on-site, type-specific and peer-led or structural HIV-prevention interventions. [ABSTRACT FROM AUTHOR]