Fast inactivation of coronavirus in filtering-facepiece respirators in a reflective cylindrical UV-C chamber.

Objective: We report on the development and characterization of a UV-C (λ  =  200 - 280 nm, λpeak = 254 nm) chamber designed for the rapid disinfection of N95 class filtering-facepiece respirators contaminated with SARS-CoV-2 coronaviruses. The device was evaluated against Betacoronavirus strain MHV-3 and its virucidal capacity was evaluated as a function of different applied UV-C doses (UV-C exposure times of 60 s, 120 s, 180 s, and 240 s) using two types of respirators geometry (shell and two-panel shapes, 3M 8801 H and 9920 H, respectively), at eight points of the respirators. Background: Most chemical disinfection methods are not recommended for N95 masks. UV-C light provided by UVGI lamps (254 nm) is an effective physical agent against viruses and bacteria due to direct photochemical harming effect on DNA/RNA, and can provide rapid disinfection for personal protective equipment such as N95/PFF2 masks. Results: The device reached a mean elimination rate of 99.9999% of MHV-3 inoculated into all the assessed different points on the tested PFF2 respirator models in a UV-C cycle of just 60 s. Statistical analysis performed through Person´s chi-square test showed no correlation between the viral infectivity reduction and the viral inoculation point (p = 0.512) and the tested respirator models (p = 0.556). However, a correlation was found between the exposure time and the viral infectivity reduction (p = 0.000*), between UV-C and no UV-C exposure. All the tested UV-C exposure times (60 s, 120 s, 180 s, and 240 s) provided the same reduction in infection rates. Therefore, 60 s was confirmed as the minimum exposure time to achieve a 99.9999% or 6 Log reduction in MHV-3 coronavirus infection rates in the PFF2 samples tested in the device. Conclusions: We conclude that the assessed UV-C chamber for the inactivation of MHV-3 coronavirus in N95/PFF2 standard masks can be a promising tool for effective and rapid disinfection of coronaviruses, including SARS-CoV-2 virus.

Solution for Interference in Hotspot Scenarios Applying Q-Learning on FFR-Based ICIC Techniques.

This work explores interference coordination techniques (inter-cell interference coordination, ICIC) based on fractional frequency reuse (FFR) as a solution for a multi-cellular scenario with user concentration varying over time. Initially, we present the problem of high user concentration along with their consequences. Next, the use of multiple-input multiple-output (MIMO) and small cells are discussed as classic solutions to the problem, leading to the introduction of fractional frequency reuse and existing ICIC techniques that use FFR. An exploratory analysis is presented in order to demonstrate the effectiveness of ICIC techniques in reducing co-channel interference, as well as to compare different techniques. A statistical study was conducted using one of the techniques from the first analysis in order to identify which of its parameters are relevant to the system performance. Additionally, another study is presented to highlight the impact of high user concentration in the proposed scenario. Because of the dynamic aspect of the system, this work proposes a solution based on machine learning. It consists of changing the ICIC parameters automatically to maintain the best possible signal-to-interference-plus-noise ratio (SINR) in a scenario with hotspots appearing over time. All investigations are based on ns-3 simulator prototyping. The results show that the proposed Q-Learning algorithm increases the average SINR from all users and hotspot users when compared with a scenario without Q-Learning. The SINR from hotspot users is increased by 11.2% in the worst case scenario and by 180% in the best case.

Cost utility of fractional flow reserve-guided percutaneous coronary intervention in multivessel coronary artery disease in Brazil.

OBJECTIVE: The fractional flow reserve (FFR) versus angiography for multivessel evaluation (FAME) study has demonstrated that FFR substantially reduces major adverse cardiac events and resource utilization in coronary artery disease (CAD) patients. We aimed to assess the cost utility of FFR in percutaneous coronary interventions (PCI) from the perspective of the Brazilian Public Health System (SUS). DESIGN: Patient-level cost-utility analysis along the FAME study. PARTICIPANTS: Multivessel coronary artery disease patients. INTERVENTION: PCI, either guided by FFR or by angiography alone. SETTING: The procedure costs were based on the mean amount of unitary resource utilization multiplied by the costs from SUS reimbursement list. The utilities were derived using Brazilian weights for time trade-off European Quality of Life-5 Dimensions. The World Health Organization recommendation based on gross domestic product per capita (international dollars [I$] 35 876/quality-adjusted life year [QALY]) was used as willingness-to-pay threshold. MAIN OUTCOME MEASURE: We determined the incremental cost-utility ratio (ICUR) in I$ per QALY gained during the 1-year time horizon. RESULTS: One-year costs were I$ 8931 for the angiography-guided PCI and I$ 8968 for the FFR-guided PCI, resulting in an incremental cost of I$ 37. Effectiveness during 1 year was 0.798 QALYs for angiography-guided PCI and 0.811 for FFR-guided PCI, resulting in an incremental effectiveness of 0.013 QALYs. The base-case ICUR of FFR versus angiography-guided PCI was 2780 I$/QALY. Cost-saving results are achieved with a FFR price reduction of at least 2.2%. CONCLUSIONS: Developing countries should give attention to strategies proven to be cost-effective in other health systems. In our analysis, FFR-guided PCI is very cost-effective in the Brazilian SUS and with a minimal price reduction of the device, FFR could be cost saving.

Aplicación intracoronaria de levosimendán en la prueba de fracción de flujo de reserva coronaria (Simdax) / Intracoronary administration of levosimendan in the coronary fractional flow reserve test

Introducción: El estudio hemodinámico de una estenosis coronaria de severidad intermedia mediante la prueba de fracción de flujo de reserva (FFR) coronaria es fundamental en términos de eventos cardiovasculares principales a corto y largo plazo. Actualmente, no se ha publicado en este contexto la aplicación intracoronaria de levosimendán. Objetivos: Determinar los efectos hemodinámicos de la administración intracoronaria de levosimendán como vasodilatador en la prueba FFR, comparado contra adenosina intracoronaria. Material y métodos: Se estudiaron mediante FFR 48 lesiones intermedias en las coronarias epicárdicas principales. Resultados: De las 48 lesiones valoradas con FFR en relación con la aplicación de adenosina versus levosimendán intracoronarios, el porcentaje de estenosis coronaria fue del 55.83 (± 11.64), FFR adenosina intracoronaria 0.8633 (± 0.1130) y FFR levosimendán intracoronario 0.8652 (± 0.1090); coeficiente de correlación 0.9859 y correlación cuadrática 0.9720. Demostrando que la inducción de vasodilatación es semejante, incluyendo casos positivos para revascularización con relación FFR < 0.80. Conclusiones: El levosimendán intracoronario en la prueba FFR presentó semejanza en la valoración de las estenosis coronarias intermedias, comparado con adenosina intracoronaria. El levosimendán representa una alternativa favorable en la inducción de hiperemia coronaria, para normar decisiones de revascularización mediante asistencia fisiológica.

Aims: The hemodynamic study of a coronary stenosis of intermediate severity, by testing fraction flow reserve (FFR) is essential in terms of major cardiovascular events in the short and long term. Currently not published in this context the intracoronary application of levosimendan. Objectives: To determine the hemodynamic effects of intracoronary administration of levosimendan, a vasodilator in the FFR test, compared with intracoronary adenosine. Material and methods: Were evaluated by FFR, 48 intermediate lesions in major epicardial coronary arteries. Results: Of the 48 lesions with FFR assessed, the application of adenosine versus intracoronary levosimendan, the percentage of coronary stenosis was 55.83 (± 11.64), intracoronary adenosine FFR 0.8633 (± 0.1130) and 0.8652 FFR intracoronary levosimendan (± 0.1090) correlation coefficient of 0.9859 and 0.9720 quadratic correlation. Demonstrating that induction of vasodilatation is similar, including revascularization positive cases compared FFR < 0.80. Conclusions: Intracoronary levosimendan in the FFR test showed similarity in the assessment of intermediate coronary stenosis compared with intracoronary adenosine. Levosimendan is an excellent alternative in the induction of coronary hyperemia decisions to regulate physiological revascularization with assistance.