238 research outputs found
Climate resilience for health care and communities: Strategies and case studies
This report provides a strategic framework for building truly climate-resilient health systems and communities, and explores how health care institutions can leverage investments to support equitable decarbonization and build community resilience, health, and wealth. Through case studies, this paper outlines actions health systems can take to improve their ability to adapt and recover from climate-driven service impacts, strengthen long-term sustainability, and support health and equity in the communities they serve
Direct electrical modulation of surface response in a single plasmonic nanoresonator
Classical electrodynamics describes the optical response of macroscopic
systems, where the boundaries between materials is treated as infinitesimally
thin. However, due to the quantum nature of electrons, interfaces acquires a
finite thickness. To include non-classical surface effects in the framework of
Maxwell's equations, surface-response functions can be introduced, also known
as Feibelman -parameters. Surface response impacts systems with strong field
localization at interfaces, which is encountered in noble metal nanoparticles
supporting surface plasmon polaritons. However, studying surface response is
challenging as it necessitates sub-nanometer control of geometric features,
e.g. the gap size in a dimer antenna, while minimizing uncertainties in
morphology. In contrast, electrical gating is convenient since the static
screening charges are confined exclusively to the surface, which alleviates the
need for precise control over the morphology. Here, we study the perturbation
of Feibelman -parameters by direct electric charging of a single plasmonic
nanoresonator and investigate the resulting changes of the resonance in
experiment and theory. The measured change of the resonance frequency matches
the theory by assuming a perturbation of the tangential surface current.
However, we also observe an unforeseen narrowing in the resonance width when
adding electrons to the surface of a plasmonic nanoresonator. These reduced
losses cannot be explained by electron spill-out within the local-response
approximation (LRA). Such an effect is likely caused by nonlocality and the
anisotropy of the perturbed local permittivity. Our findings open up
possibilities to reduce losses in plasmonic resonators and to develop ultrafast
and extremely small electrically driven plasmonic modulators and metasurfaces
by leveraging electrical control over non-classical surface effects.Comment: 10 pages, 3 figures, 15 pages Supplementar
Evaluation of total body weight and body mass index cut-offs for increased cefazolin dose for surgical prophylaxis
AbstractFrench and American guidelines recommend increased dosage regimens of cefazolin (CFZ) for surgical prophylaxis in patients with a body mass index (BMI) ≥ 35 kg/m2 or with a total body weight (TBW) ≥ 120 kg. The objective of this study was to evaluate the accuracy of these cut-offs in identifying patients who require CFZ dose adjustment. A pharmacokinetic study was conducted in patients of varying TBW and BMI who received 2 g of CFZ intravenously for prophylaxis prior to digestive surgery. Adequacy of therapy, defined as a serum concentration of unbound CFZ (fCFZ) ≥ 4 mg/L, was evaluated 180 min (T180) and 240 min (T240) after the start of CFZ infusion. Possible factors associated with insufficient fCFZ levels were also assessed. A P-value of <0.05 was considered statistically significant. A total of 63 patients were included in the study, categorised according to BMI (<35 kg/m2, 20 patients; and ≥35 kg/m2, 43 patients) and TBW (<120 kg, 41 patients; and ≥120 kg, 22 patients). All patients had adequate drug levels at T180 but only 40/63 patients (63%) had adequate levels at T240. At T240, therapy was adequate in 15/20 patients (75%) and 25/43 patients (58%) with BMI <35 kg/m2 and ≥35 kg/m2, respectively (P = 0.20), and in 28/41 patients (68%) and 12/22 patients (55%) with TBW <120 kg and ≥120 kg, respectively (P = 0.28). No factor associated with insufficient fCFZ was identified. In conclusion, current BMI and TBW cut-offs are poor indicators of which patients could benefit from increased CFZ dosage regimens
Appetite and gut hormone responses to moderate-intensity continuous exercise versus high-intensity interval exercise, in normoxic and hypoxic conditions.
This study investigated the effects of continuous moderate-intensity exercise (MIE) and high-intensity interval exercise (HIIE) in combination with short exposure to hypoxia on appetite and plasma concentrations of acylated ghrelin, peptide YY (PYY), and glucagon-like peptide-1 (GLP-1). Twelve healthy males completed four, 2.6 h trials in a random order: 1) MIE-normoxia, 2) MIE-hypoxia, 3) HIIE-normoxia, and 4) HIIE-hypoxia. Exercise took place in an environmental chamber. During MIE, participants ran for 50 min at 70% of altitude-specific maximal oxygen uptake ( 2max) and during HIIE performed 6 x 3 min running at 90% 2max interspersed with 6 x 3 min active recovery at 50% 2max with a 7 min warm-up and cool-down at 70% 2max (50 min total). In hypoxic trials, exercise was performed at a simulated altitude of 2,980 m (14.5% O2). Exercise was completed after a standardised breakfast. A second meal standardised to 30% of participants’ daily energy requirements was provided 45 min after exercise. Appetite was suppressed more in hypoxia than normoxia during exercise, post-exercise, and for the full 2.6 h trial period (linear mixed modelling, p 0.05). These findings demonstrate that short exposure to hypoxia causes suppressions in appetite and plasma acylated ghrelin concentrations. Furthermore, appetite responses to exercise do not appear to be influenced by exercise modality
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