2,911 research outputs found
The First-Bite Syndrome
Patients presenting with esophageal disorders often describe what can be called a first-bite syndrome. The condition can be discerned by its characteristic clinical features. It may be a variant of diffuse esophageal spasm. While in a majority of patients it is a benign functional disturbance, it can be a harbinger of carcinoma. When of functional origin, it is amenable, in most cases, to relatively simple medical management
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Randomized Controlled Trial of an Internet Application to Reduce HIV Transmission Behavior Among HIV Infected Men Who have Sex with Men.
We conducted a prospective, randomized controlled trial of an internet-based safer-sex intervention to reduce HIV transmission risk behaviors. HIV-infected men who have sex with men (n = 179) were randomized to receive a monthly internet survey alone or a monthly survey plus tailored risk reduction messages over 12 months. The primary outcome was the cumulative sexually transmitted infection (STI) incidence over 12 months. Secondary outcomes included self-reported unprotected sex with an at risk partner and disclosure of HIV status to partners. In a modified intent to treat analysis, there was no difference in 12-month STI incidence between the intervention and control arms (30 vs. 25 %, respectively; p = 0.5). Unprotected sex decreased and disclosure increased over time in both study arms. These improvements suggest that addition of the risk-reduction messages provided little benefit beyond the self-monitoring of risky behavior via regular self-report risk behavior assessments (as was done in both study arms)
Parallel Quantum-Point-Contacts as High-Frequency-Mixers
We present the results of high-frequency mixing experiments performed upon
parallel quantum point-contacts defined in the two-dimensional electron gas of
an Al_{x}Ga_{1-x}As/GaAs-heterostructure. The parallel geometry, fabricated
using a novel double-resist technology, enables the point-contact device to be
impedance matched over a wide frequency range and, in addition, increases the
power levels of the mixing signal while simultaneously reducing the parasitic
source-drain capacitance. Here, we consider two parallel quantum point-contact
devices with 155 and 110 point-contacts respectively; both devices operated
successfully at liquid helium and liquid nitrogen temperatures with a minimal
conversion loss of 13 dB.Comment: 4 figures, RevTeX, to be published in the 16 June 1997 issue of
Applied Physic Letter
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