The size and operating energy of a nonlinear optical device are fundamentally constrained by the weakness of the nonlinear optical response of common materials1. Here, we report that a 50-nm-thick ...optical metasurface made of optical dipole antennas coupled to an epsilon-near-zero material exhibits a broadband (∼400 nm bandwidth) and ultrafast (recovery time less than 1 ps) intensity-dependent refractive index n2 as large as −3.73 ± 0.56 cm2 GW−1. Furthermore, the metasurface exhibits a maximum optically induced refractive index change of ±2.5 over a spectral range of ∼200 nm. The inclusion of low-Q nanoantennas on an epsilon-near-zero thin film not only allows the design of a metasurface with an unprecedentedly large nonlinear optical response, but also offers the flexibility to tailor the sign of the response. Our technique removes a longstanding obstacle in nonlinear optics: the lack of materials with an ultrafast nonlinear contribution to refractive index on the order of unity. It consequently offers the possibility to design low-power nonlinear nano-optical devices with orders-of-magnitude smaller footprints.
COVID-19 is a multi-systemic disease which can target the lungs and the cardiovascular system and can also affect parts of the brain for prolonged periods of time. Even healthy athletes without ...comorbidities can be psychologically affected long-term by COVID-19.
This study aimed to investigate athletes' perceived mental stress and recovery levels in daily life, and their maximal aerobic power, at three different time points, post COVID-19.
In total, 99 athletes (62.6% male), who had been infected by COVID-19, filled out the Recovery Stress Questionnaire for Athletes (REST-Q-Sport) and completed cardiopulmonary exercise testing (endpoint maximal aerobic power output (Pmax)) at the initial screening (t1: 4 months after infection). Follow-up assessments occurred three (t2, n = 37) and seven months after t1 (t3, n = 19).
Subgroup means from the Recovery category were significantly below the reference value of four at all three time points, except "General Recovery" (3.76 (± 0.96), p = 0.275, d = 0.968) at t3."Overtiredness" (2.34 (± 1.27), p = 0.020, r = 0.224) was significantly above the reference value of two at t1, while all other Stress subgroups were not significantly different from the reference value or were significantly below the maximum threshold of two at t1, t2 and t3. Spearman's ρ revealed a negative association between Pmax and the subcategories of stress (ρ = -0.54 to ρ = -0.11, p < 0.050), and positive correlations between Pmax and "Somatic Recovery" (ρ = 0.43, p < 0.001) and "General Recovery" (ρ = 0.23, p = 0.040) at t1. Pmax (t1: 3.83 (± 0.99), t2: 3.78 (± 1.14), β = 0.06, p < 0.003) increased significantly from t1 to t2. In addition, REST-Q-Sport indicated a decrease in "Sleep" (t2 = 2.35 (± 0.62), t3 = 2.28(± 0.61), β = -0.18, p < 0.023) at t3, when compared to t2.
The perceived recovery seems to be negatively affected in post COVID-19 athletes. Physical performance post COVID-19 correlates with both "Emotional and Somatic Stress" and "Somatic and General Recovery", indicating potential mental and physical benefits of exercise. While it is evident that COVID-19, like other viral infections, may have an influence on physical performance, monitoring stress and recovery perceptions of athletes is critical to facilitate their return-to-sports, while minimizing long-term COVID-19 induced negative effects like the athletic objective and subjective perceived recovery and stress levels.
We demonstrate temperature-controlled spectral tunability of a partially-pumped single-wavelength random laser in a solid-state random laser based on DCM ...4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran doped PMMA (polymethyl methacrylate) dye. By carefully shaping the spatial profile of the pump, we first achieve a low-threshold, single-mode random lasing with an excellent side lobe rejection. Notably, we show how temperature-induced changes in the refractive index of the PMMA-DCM layer result in a blue shift of this single lasing mode. We demonstrate spectral tunability over an 8nm-wide bandwidth.
Background
The supply of viable organ donations falls significantly below the demand. Discrepancies concerning the availability of transplants cannot be explained solely by the various consent models ...used in different countries. There is evidence that religious beliefs of patients, potential donors, and healthcare professionals also play an important role in the decision‐making process. However, to date, very little research has been conducted on the consequences of specific religious beliefs on transplantation rates. The aim of this review was to outline the religious views of Christians, Muslims, Jews, Hindus, and Buddhists on organ donation. Additionally, different approaches to address this topic throughout the world are presented and can function as a helpful background for medical professionals.
Methods
The umbrella organizations of the five largest religious movements were asked for written statements concerning the subject of organ transplantation, and a literature review was performed.
Results
All German religious umbrella organizations have a positive view on organ donation, if certain rules are respected. Particularly, deceased donations are supported as a sign of altruism, love, and respect for another human being. Different aspects of the transplant process (e.g., consent, brain death, and respect for the dead body) are particularly stressed in some religions.
Conclusions
In general, the religious groups addressed here are in favor of organ donations. Nevertheless, there are important particularities to be considered. Hopefully, understanding the different religious views on organ donations will help in reducing religious concerns about transplantation and narrowing the gap between the need and the availability of organ donations.
Abstract
Light beams with a helical phase-front possess orbital angular momentum along their direction of propagation in addition to the spin angular momentum that describes their polarisation. Until ...recently, it was thought that these two ‘rotational’ motions of light were largely independent and could not be coupled during light–matter interactions. However, it is now known that interactions with carefully designed complex media can result in spin-to-orbit coupling, where a change of the spin angular momentum will modify the orbital angular momentum and
vice versa
. In this work, we propose and demonstrate that the birefringence of plasmonic nanostructures can be wielded to transform circularly polarised light into light carrying orbital angular momentum. A device operating at visible wavelengths is designed from a space-variant array of subwavelength plasmonic nano-antennas. Experiment confirms that circularly polarised light transmitted through the device is imbued with orbital angular momentum of ±2
ħ
(with conversion efficiency of at least 1%). This technology paves the way towards ultrathin orbital angular momentum generators that could be integrated into applications for spectroscopy, nanoscale sensing and classical or quantum communications using integrated photonic devices.
Vaccination represents the key strategy to control the COVID-19 pandemic through induction of neutralising antibody responses and T cell-associated immunity that substantially decrease the risk of ...developing severe disease.1,2 However, individuals who are immunocompromised (eg, because of comorbidities, high age, or immunosuppressive treatment) might not mount a full adaptive immune response and thus remain susceptible. For individuals at high risk, individual monoclonal antibodies (mAbs) or cocktails of mAbs are administered as prophylaxis or therapy.3,4 All mAbs currently approved by the US Food and Drug Administration (FDA) or European Medicines Agency (EMA) target the spike (S) protein (appendix pp 1–2).5 During the course of the COVID-19 pandemic, several SARS-CoV-2 lineages evolved mutations that confer partial or full resistance against some mAbs.6–9 Consequently, only few mAbs remain suitable for treatment of individuals at high risk, and only bebtelovimab shows high efficacy against multiple omicron sublineages.8 However, novel omicron sublineages have been detected, harbouring additional S protein mutations within the epitopes of bebtelovimab and other mAbs (figure A; appendix p 11). ...none of the tested mAbs or mAb cocktails caused appreciable neutralisation of BQ.1.1pp (figure B–C; appendix p 12).
The rapid spread of the SARS-CoV-2 Omicron variant suggests that the virus might become globally dominant. Further, the high number of mutations in the viral spike protein raised concerns that the ...virus might evade antibodies induced by infection or vaccination. Here, we report that the Omicron spike was resistant against most therapeutic antibodies but remained susceptible to inhibition by sotrovimab. Similarly, the Omicron spike evaded neutralization by antibodies from convalescent patients or individuals vaccinated with the BioNTech-Pfizer vaccine (BNT162b2) with 12- to 44-fold higher efficiency than the spike of the Delta variant. Neutralization of the Omicron spike by antibodies induced upon heterologous ChAdOx1 (Astra Zeneca-Oxford)/BNT162b2 vaccination or vaccination with three doses of BNT162b2 was more efficient, but the Omicron spike still evaded neutralization more efficiently than the Delta spike. These findings indicate that most therapeutic antibodies will be ineffective against the Omicron variant and that double immunization with BNT162b2 might not adequately protect against severe disease induced by this variant.
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•Omicron uses human and animal ACE2 for host cell entry•Omicron is resistant against neutralization by several therapeutic antibodies•Omicron efficiently evades antibodies from infected or 2 × BNT-vaccinated patients•Omicron moderately evades antibodies induced by 3 × BNT or heterologous vaccination
The SARS-CoV-2 Omicron variant is rapidly spreading worldwide and a public health concern. Experiments show that this variant is resistant against several therapeutic antibodies for COVID-19 and efficiently evades antibodies induced upon infection or double BNT162b2 vaccination, but not triple BNT162b2 or ChAdOx1/BNT162b2 vaccination.
The global spread of SARS-CoV-2/COVID-19 is devastating health systems and economies worldwide. Recombinant or vaccine-induced neutralizing antibodies are used to combat the COVID-19 pandemic. ...However, the recently emerged SARS-CoV-2 variants B.1.1.7 (UK), B.1.351 (South Africa), and P.1 (Brazil) harbor mutations in the viral spike (S) protein that may alter virus-host cell interactions and confer resistance to inhibitors and antibodies. Here, using pseudoparticles, we show that entry of all variants into human cells is susceptible to blockade by the entry inhibitors soluble ACE2, Camostat, EK-1, and EK-1-C4. In contrast, entry of the B.1.351 and P.1 variant was partially (Casirivimab) or fully (Bamlanivimab) resistant to antibodies used for COVID-19 treatment. Moreover, entry of these variants was less efficiently inhibited by plasma from convalescent COVID-19 patients and sera from BNT162b2-vaccinated individuals. These results suggest that SARS-CoV-2 may escape neutralizing antibody responses, which has important implications for efforts to contain the pandemic.
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•B.1.1.7, B.1.351, and P.1 do not show augmented host cell entry•Entry inhibitors under clinical evaluation block all variants•B.1.351 and P.1 can escape from therapeutic antibodies•B.1.351 and P.1 evade antibodies induced by infection and vaccination
Comparison of the SARS-CoV-2 variants B.1.1.7, B.1.351, and P.1 shows that inhibitors under clinical evaluation are still effective in blocking entry, though the B.1.351 and P.1 variants evade antibody responses induced upon infection as well as vaccination and evade certain therapeutic antibodies.
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