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

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 Cu2_2MnM (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 Cu$_2$MnM (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