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Coinfection with human immunodeficiency virus (HIV) and viral hepatitis is associated with high morbidity and mortality in the absence of clinical management, making identification of these cases crucial. We examined characteristics of HIV and viral hepatitis coinfections by using surveillance data from 15 US states and two cities. Each jurisdiction used an automated deterministic matching method to link surveillance data for persons with reported acute and chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infections, to persons reported with HIV infection. Of the 504 398 persons living with diagnosed HIV infection at the end of 2014, 2.0% were coinfected with HBV and 6.7% were coinfected with HCV. Of the 269 884 persons ever reported with HBV, 5.2% were reported with HIV. Of the 1 093 050 persons ever reported with HCV, 4.3% were reported with HIV. A greater proportion of persons coinfected with HIV and HBV were males and blacks/African Americans, compared with those with HIV monoinfection. Persons who inject drugs represented a greater proportion of those coinfected with HIV and HCV, compared with those with HIV monoinfection. Matching HIV and viral hepatitis surveillance data highlights epidemiological characteristics of persons coinfected and can be used to routinely monitor health status and guide state and national public health interventions.
We consider energy transfer between non-equal nanoparticles mediated by a quantum system. The nanoparticles are considered as thermal reservoirs described as ensembles of finite numbers of harmonic oscillators within the Drude-Ullersma model having mode spacings Δ1 and Δ2. Our approach is based on the generalized quantum Langevin equation. The quasi-static energy transport between the thermal reservoirs is investigated. As is shown, the double degeneracy of the mode frequencies, which occurred in the previously considered case when Δ1 = Δ2, is removed in the present case of non-equal mode spacings. Equations describing long-time (t ∼1/Δ1,2) relaxation for the mode temperatures (or the ensemble averaged mode energies) are solved and the resulting expression for the total energy current between the nanoparticles is derived and explored.
We consider finite size effects on energy transfer between nanoparticles mediated by quantum systems. The nanoparticles are considered as heat reservoirs with a finite number of modes. An expression for the quasi-static energy transport between the heat reservoirs having a finite mode frequency spacing Δ is derived. The resulting equations describing long-term (t ≥1/Δ) relaxation for the mode temperatures and the average temperatures of the nanoparticles are solved. The solutions depend on small number of measurable parameters and show unusual peculiarities in their temporal variations. As is shown, Fourier’s law in a chain of identical subsystems (nanoparticles) can be validated only on a short time scale. For a larger times, when t ∼ 1/Δ, the temperatures of different modes deviate from each other, thus preventing thermal equilibrium in each subsystem, and the validity of Fourier’s law cannot be established.
We explore a model of heat transport between two heat reservoirs mediated by a quantum particle. The reservoirs are modeled as ensembles of harmonic modes linearly coupled to the mediator. The steady state heat current, as well as the thermal conductance are obtained for arbitrary coupling strength and will be analyzed for the cases of weak and strong coupling regimes. It is shown that the violation of the virial theorem – the imbalance between the average potential and kinetic energy of the mediator – can be considered as a measure of the coupling strength that takes into account all the relevant factors. The dependence of the thermal conductance on the coupling strength is non-monotonic and displays a maximum. Temperature dependence of the heat conductance may reach a plateau at intermediate temperatures, similar to the classical plateau at high temperatures. We will discuss the origin of Fourier’s law in a chain of macroscopically large, but finite subsystems coupled by the quantum mediators. We will also address the origin of the anomalously large heat current between the scanning tunneling microscope tip and the substrate in deep vacuum which was found in recent experiments.
Experimental analysis and simulation of the formation and electrical characterization of TiSi2/+/p-Si shallow junctions are presented here. The formation of shallow n+-p junction, by ion implantation of As through Ti films evaporated on p-Si substrates followed by Rapid Thermal Annealing (RTA) and conventional furnace annealing has been performed in these experiments. Structural techniques such as Secondary Ion Mass Spec-troscopy (SIMS) and Rutherford Backscattering (RBS) experiments have been employed to characterize these devices. RUMP simulations were used to analyze and interpret the RBS data. Current-voltage characteristics have been simulated using PISCES simulator.
Using a magnetic field to confine the plasma closer to the cathode has been shown to be advantageous in dry etching technology since this yields a high degree of ionization at low pressures. We report here the results of a study of magnetron reactive ion etching of GaAs using a freon discharge. Various characterization techniques have been employed to understand the etching process and identify the extent of surface damage. The results show that magnetron etching is capable of yielding high etch rates with low damage.
The formation of low temperature Au-Ge contacts to n-GaAs is a two-step process. In the first step, the metals segregate into Au and Ge rich regions and the intermixing of the Au and Ge with the Ga and As causes a reduction in the barrier height. The second step occurs after extended annealing, during which time Au and Ge continue to diffuse into the substrate. An orthorhombic Au-Ga phase is formed and it is likely that other Au-Ga or Ge-As phases are formed. The length of the extended anneal is dependent upon the atomic percent of Ge in the film, with the 10 at. % Ge taking 6 hr., the 27 at. % Ge taking 3 hr. and the 50 at. % Ge taking 9 hr. to become ohmic. The 75 at. % Ge sample doesn’t show ohmic behavior even after 33 hr. of annealing. The metal-semiconductor interface configuration appears abrupt, showing no protrusions into the GaAs substrate.
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