RESUMO
We demonstrate a 1D magneto-optical trap of the polar free radical calcium monohydroxide (CaOH). A quasiclosed cycling transition is established to scatter â¼10^{3} photons per molecule, predominantly limited by interaction time. This enables radiative laser cooling of CaOH while compressing the molecular beam, leading to a significant increase in on axis beam brightness and reduction in temperature from 8.4 to 1.4 mK.
RESUMO
Bioaerosols are known to be an important transmission pathway for SARS-CoV-2. We report a framework for estimating the risk of transmitting SARS-CoV-2 via aerosols in laboratory and office settings, based on an exponential dose-response model and analysis of air flow and purification in typical heating, ventilation, and air conditioning (HVAC) systems. High-circulation HVAC systems with high-efficiency particulate air (HEPA) filtration dramatically reduce exposure to the virus in indoor settings, and surgical masks or N95 respirators further reduce exposure. As an example of our risk assessment model, we consider the precautions needed for a typical experimental physical science group to maintain a low risk of transmission over six months of operation. We recommend that, for environments where fewer than five individuals significantly overlap, work spaces should remain vacant for between one (high-circulation HVAC with HEPA filtration) to six (low-circulation HVAC with no filtration) air exchange times before a new worker enters in order to maintain no more than 1% chance of infection over six months of operation in the workplace. Our model is readily applied to similar settings that are not explicitly given here. We also provide a framework for evaluating infection mitigation through ventilation in multiple occupancy spaces.
Assuntos
Poluição do Ar em Ambientes Fechados/prevenção & controle , Infecções por Coronavirus/transmissão , Laboratórios/normas , Modelos Estatísticos , Pneumonia Viral/transmissão , Ventilação/normas , Local de Trabalho/normas , Ar Condicionado/normas , Betacoronavirus , COVID-19 , Infecções por Coronavirus/epidemiologia , Humanos , Saúde Ocupacional , Pandemias , Pneumonia Viral/epidemiologia , Medição de Risco , SARS-CoV-2RESUMO
The condition known as Takayasu's disease or Takayasu's arteritis is a type of vascular inflammation that affects the large and medium arteries. It can lead to a reduction in blood flow to various parts of the body, and it can cause severe complications. Patients with this disease may not have specific symptoms, which can lead to their diagnosis not being confirmed. Takayasu's disease is believed to be a probable cause of stroke in young patients. Although stroke is a common cause of morbidity, it is usually not an initial presentation in Takayasu's disease. In this study, a young female with left-sided hemiparesis was diagnosed with Takayasu's disease after a clinical and angiographic examination.
RESUMO
Ultracold polyatomic molecules have potentially wide-ranging applications in quantum simulation and computation, particle physics, and quantum chemistry. For atoms and small molecules, direct laser cooling has proven to be a powerful tool for quantum science in the ultracold regime. However, the feasibility of laser-cooling larger, nonlinear polyatomic molecules has remained unknown because of their complex structure. We laser-cooled the symmetric top molecule calcium monomethoxide (CaOCH3), reducing the temperature of ~104 molecules from 22 ± 1 millikelvin to 1.8 ± 0.7 millikelvin in one dimension and state-selectively cooling two nuclear spin isomers. These results demonstrate that the use of proper ro-vibronic transitions enables laser cooling of nonlinear molecules, thereby opening a path to efficient cooling of chiral molecules and, eventually, optical tweezer arrays of complex polyatomic species.