A cryogenic rotation stage with a large clear aperture for the half-wave plates in the Spider instrument

We describe the cryogenic half-wave plate rotation mechanisms built for and used in Spider, a polarization-sensitive balloon-borne telescope array that observed the Cosmic Microwave Background at 95 GHz and 150 GHz during a stratospheric balloon flight from Antarctica in January 2015. The mechanisms operate at liquid helium temperature in flight. A three-point contact design keeps the mechanical bearings relatively small but allows for a large (305 mm) diameter clear aperture. A worm gear driven by a cryogenic stepper motor allows for precise positioning and prevents undesired rotation when the motors are depowered. A custom-built optical encoder system monitors the bearing angle to an absolute accuracy of +/- 0.1 degrees. The system performed well in Spider during its successful 16 day flight.Comment: 11 pages, 7 figures, Published in Review of Scientific Instruments. v2 includes reviewer changes and longer literature revie

Benefit and Risks of Aspirin in Addition to Ticagrelor in Acute Coronary Syndromes:A Post Hoc Analysis of the Randomized GLOBAL LEADERS Trial

Key PointsQuestionWhat are the benefits and risks of continuing aspirin in addition to P2Y12 receptor inhibition with ticagrelor among patients with acute coronary syndrome between 1 month and 12 months after percutaneous coronary intervention? FindingsIn this nonprespecified, post hoc analysis of the GLOBAL LEADERS randomized clinical trial, beyond 1 month after percutaneous coronary intervention in acute coronary syndrome, aspirin was associated with increased bleeding risk and appeared not to add to the benefit of ticagrelor on ischemic events. MeaningThe findings of this hypothesis-generating analysis pave the way for further trials evaluating aspirin-free antiplatelet strategies after percutaneous coronary intervention. ImportanceThe role of aspirin as part of antiplatelet regimens in acute coronary syndromes (ACS) needs to be clarified in the context of newer potent P2Y12 antagonists. ObjectiveTo evaluate the benefit and risks of aspirin in addition to ticagrelor among patients with ACS beyond 1 month after percutaneous coronary intervention (PCI). Design, Setting, and ParticipantsThis is a nonprespecified, post hoc analysis of GLOBAL LEADERS, a randomized, open-label superiority trial comparing 2 antiplatelet treatment strategies after PCI. The trial included 130 secondary/tertiary care hospitals in different countries, with 15991 unselected patients with stable coronary artery disease or ACS undergoing PCI. Patients had outpatient visits at 1, 3, 6, 12, 18, and 24 months after index procedure. InterventionsThe experimental group received aspirin plus ticagrelor for 1 month followed by 23-month ticagrelor monotherapy; the reference group received aspirin plus either clopidogrel (stable coronary artery disease) or ticagrelor (ACS) for 12 months, followed by 12-month aspirin monotherapy. In this analysis, we examined the clinical outcomes occurring between 31 days and 365 days after randomization, specifically in patients with ACS who, within this time frame, were assigned to receive either ticagrelor alone or ticagrelor and aspirin. Main Outcomes and MeasuresThe primary outcome was the composite of all-cause death or new Q-wave myocardial infarction. ResultsOf 15968 participants, there were 7487 patients with ACS enrolled; 3750 patients were assigned to the experimental group and 3737 patients to the reference group. Between 31 and 365 days after randomization, the primary outcome occurred in 55 patients (1.5%) in the experimental group and in 75 patients (2.0%) in the reference group (hazard ratio [HR], 0.73; 95% CI, 0.51-1.03; P=.07); investigator-reported Bleeding Academic Research Consortium-defined bleeding type 3 or 5 occurred in 28 patients (0.8%) in the experimental group and in 54 patients (1.5%) in the reference arm (HR, 0.52; 95% CI, 0.33-0.81; P=.004). Conclusions and RelevanceBetween 1 month and 12 months after PCI in ACS, aspirin was associated with increased bleeding risk and appeared not to add to the benefit of ticagrelor on ischemic events. These findings should be interpreted as exploratory and hypothesis generating; however, they pave the way for further trials evaluating aspirin-free antiplatelet strategies after PCI. Trial RegistrationClinicalTrials.gov identifier: NCT01813435. This secondary analysis of the GLOBAL LEADERS randomized clinical trial evaluates the benefit and risks of aspirin in addition to ticagrelor among patients with acute coronary syndrome beyond 1 month after percutaneous coronary intervention

Increased circulation time of Plasmodium falciparum underlies persistent asymptomatic infection in the dry season

The dry season is a major challenge for Plasmodium falciparum parasites in many malaria endemic regions, where water availability limits mosquito vectors to only part of the year. How P. falciparum bridges two transmission seasons months apart, without being cleared by the human host or compromising host survival, is poorly understood. Here we show that low levels of P. falciparum parasites persist in the blood of asymptomatic Malian individuals during the 5- to 6-month dry season, rarely causing symptoms and minimally affecting the host immune response. Parasites isolated during the dry season are transcriptionally distinct from those of individuals with febrile malaria in the transmission season, coinciding with longer circulation within each replicative cycle of parasitized erythrocytes without adhering to the vascular endothelium. Low parasite levels during the dry season are not due to impaired replication but rather to increased splenic clearance of longer-circulating infected erythrocytes, which likely maintain parasitemias below clinical and immunological radar. We propose that P. falciparum virulence in areas of seasonal malaria transmission is regulated so that the parasite decreases its endothelial binding capacity, allowing increased splenic clearance and enabling several months of subclinical parasite persistence

Evaluation clinique a long terme après angioplastie coronaire chez le sujet âgé de plus de 75 ans (à propos d'une cohorte consécutive de 512 patients)

Objectif : L'allongement de l'espérance de vie et l'amélioration des techniques percutanées de revascularisation myocardique ont considérablement modifié la prise en charge interventionnelle des sujets âgés coronariens. Peu d'études nous renseignent sur l'évolution clinique à long terme après angioplastie coronaire (ATC). Ce travail étudie la mortalité et les évènements cardiaques et cérébro-vasculaires (MACCE) à long terme après ATC chez les sujets âgés. Matériels et méthode : La mortalité et l'évolution clinique à long terme ont été étudiées à partir d'un registre monocentrique de 512 patients consécutifs de plus de 75 ans, traités par ATC entre 2000 et 2001. Après un suivi moyen de plus de 4 ans, la mortalité, les évènements cardiaques et cérébro-vasculaires majeurs, définis par les décès, les infarctus du myocarde, les AVC, les nouvelles revascularisations coronaires, ont été comparés entre le groupe I (315 patients de 75 79 ans) et le groupe II (197 patients de plus de 80 ans). Résultats : La mortalité et les MACCE hospitaliers ne sont pas différents entre les deux groupes. En analyse multivariée, les facteurs prédictifs indépendants de complications hospitalières sont un SCA ST+, une FEVG < 40 %, un antécédent de pontage aorto-coronaire. Après un suivi moyen de 51,3 mois, le groupe des plus 80 ans présente une surmortalité, de cause cardiaque ou non (41,62 % vs 26,03 %, p <0,0001). En analyse multivariée, les facteurs prédictifs indépendants de décès à long terme sont : une FEVG <40 %, la créatininémie, un antécédent de chirurgie carotidienne ou d'AVC/AIT. Les taux de MACCE ne sont statistiquement pas différents entre les deux groupes et les facteurs prédictifs indépendants de MACCE à long terme sont : une FEVG < 40 % et la présence de lésions tritronculaires par rapport aux monotronculaires. Conclusion : Bien que l'âge, en tant que tel, n'apparaisse pas comme facteur indépendant de morbi-mortalité à long terme, l'évolution clinique après angioplastie chez le sujet âgé est grevée par ses co-morbidités qui conditionnent le pronostic.TOULOUSE3-BU Santé-Centrale (315552105) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF