16,986 research outputs found
Polarization-controlled single photons
Vacuum-stimulated Raman transitions are driven between two magnetic substates
of a rubidium-87 atom strongly coupled to an optical cavity. A magnetic field
lifts the degeneracy of these states, and the atom is alternately exposed to
laser pulses of two different frequencies. This produces a stream of single
photons with alternating circular polarization in a predetermined
spatio-temporal mode. MHz repetition rates are possible as no recycling of the
atom between photon generations is required. Photon indistinguishability is
tested by time-resolved two-photon interference.Comment: 4 pages, 3 figure
Pharmacological activation of endogenous protective pathways against oxidative stress under conditions of sepsis
Funding The study was funded entirely by institutional funds.Peer reviewedPostprin
The Minimum Clinically Important Difference on the Sleep Disorders Inventory for People with Dementia
Objectives:
Sleep disturbances in dementia causes distress to people with dementia and their family carers and are associated with care home admission. The Sleep Disorders Inventory (SDI) is a validated questionnaire of sleep disturbances in dementia often used to measure treatment effectiveness, but the minimum clinically important difference (MCID) is unknown.
Methods:
We triangulated three investigative methods to determine the MCID of the SDI. Using data on SDI from a randomised controlled trial (RCT) with 62 participants in an intervention for sleep disorders in dementia, we (1) calculated distribution‐based values where MCID = 0.33 of a SD (SD) (2) an anchor based approach using quality of life (measured using DEMQOL‐Proxy) as an anchor. We also employed a Delphi consensus process asking 12 clinicians, sleep researchers and family carers to rate which changes on vignettes were equivalent to a MCID.
Results:
We found that 0.33 SD in the SDI = 4.86. Reduction in SDI total score was not significantly correlated with improvement in DEMQOL‐Proxy (Pearson's correlation = −0.01; P = 0.96) score. The Delphi consensus required two rounds to reach a consensus and concluded that changes equivalent to three points on the SDI equated to the MCID.
Conclusions:
Taking into account both the distribution‐based values and the Delphi process we used a whole number at the midpoint and judged the minimum clinically important difference MCID to be equal to four points. We note the clinicians and carers opinions from the Delphi process determined the MCID to be lower at three points
Finite element analysis of notched bar skeletal point stresses and dimension changes due to creep
Role of the exchange and correlation potential into calculating the x-ray absorption spectra of half-metallic alloys: the case of Mn and Cu K-edge XANES in CuMnM (M = Al, Sn, In) Heusler alloys
This work reports a theoretical study of the x-ray absorption near-edge
structure spectra at both the Cu and the Mn K-edge in several CuMnM (M= Al,
Sn and In) Heusler alloys. Our results show that {\it ab-initio} single-channel
multiple-scattering calculations are able of reproducing the experimental
spectra. Moreover, an extensive discussion is presented concerning the role of
the final state potential needed to reproduce the experimental data of these
half-metallic alloys. In particular, the effects of the cluster-size and of the
exchange and correlation potential needed in reproducing all the experimental
XANES features are discussed.Comment: 15 pages, 5 figure
Effect of HIV infection and antiretroviral therapy on hepatitis B virus (HBV)-specific T cell responses in patients who have resolved HBV infection
Coinfection with hepatitis B virus (HBV) is a common occurrence in human immunodeficiency virus (HIV)–positive patients and an increasing cause of morbidity and mortality. The CD8+ T cell response is critical for long-term control of HBV in patients resolving acute infection. Here, we examine the effect of HIV on HBV-specific CD8+ T cell responses in patients who have resolved HBV infection. A cross-sectional study showed a reduction in HBV-specific CD8+ T cell responses in HIV-positive, HBV-immune patients, compared with those in HIV-negative, HBV-immune patients. A longitudinal study of a subgroup of patients examined whether this attrition could be reversed by effective antiretroviral therapy. The introduction of highly active antiretroviral therapy (HAART) resulted in reconstitution of some HBV-specific CD4+ and CD8+ T cell responses, in association with restoration of CD4+ T cell counts. These data provide a mechanism to account for the observed impairment of control of HBV infection in the setting of HIV infection and support the ability of HAART to reconstitute functionally active T cell responses
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