12 research outputs found

    Repeated Impact-Based Capture of a Spinning Object by a Dual-Arm Space Robot

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    This paper presents detumbling and capture of space debris by a dual-arm space robot for active space debris removal missions. Space debris, such as a malfunctioning satellite or a rocket upper stage, often has uncontrolled tumbling motion. It also has uncertainties in its parameters, such as inertial characteristics or surface frictional roughness. These factors make the debris capture missions difficult to accomplish. To cope with such challenging missions, we propose a detumbling and capture control method for a dual-arm robot based on repeated impact capable of suppressing the debris motion by repeatedly utilizing an effect of a passive damping factor in the contact characteristics. In this paper, as the initial step of a study on the repeated impact-based capture method, we assume that the capture target is a rocket upper stage that can be simply modeled as a cylindrical body and mainly has angular velocity motion in its principle axis of inertia. A motion tracking control law of an end-effector of the robot arm is introduced to maintain the repeated impact. The proposed control method enables the robot to accomplish the detumbling and capture without precise estimation of the inertial characteristics and surface frictional roughness of the debris. The validity of the proposed method is presented by numerical simulations and planar microgravity experiments using an air-floating system. In particular, the experimental evaluation shows the fundamental feasibility of the proposed method, and thus, the result contributes to a practical application

    Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

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    Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

    Identification of Highly Potent Human Immunodeficiency Virus Type-1 Protease Inhibitors against Lopinavir and Darunavir Resistant Viruses from Allophenylnorstatine-Based Peptidomimetics with P2 Tetrahydrofuranylglycine

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    The emergence of drug-resistant HIV from a wide spreading anti-viral chemotherapy targeting the HIV protease in the past decades is unavoidable and provides a challenge to develop alternative inhibitors. We synthesized a series of allophenylnorstatine-based peptidomimetics with various P3, P2 and P2´ moieties. The derivatives with P2 tetrahydrofuranylglycine (Thfg) were found to be potent against wild type HIV-1 protease and the virus, identifying a highly potent compound 21f (KNI-1657) against lopinavir/ritonavir- or darunavir-resistant strains. Co-crystal structures of 21f and the wild-type protease revealed numerous key hydrogen bonding interactions with the Thfg. These results suggest that the strategy to design allophenylnorstatine-based peptidomimetics combined with Thfg residue would be promising for generating candidates to overcome multi-drug resistance

    Identification of Highly Potent Human Immunodeficiency Virus Type‑1 Protease Inhibitors against Lopinavir and Darunavir Resistant Viruses from Allophenylnorstatine-Based Peptidomimetics with P2 Tetrahydrofuranylglycine

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    The emergence of drug-resistant HIV from a widespread antiviral chemotherapy targeting HIV protease in the past decades is unavoidable and provides a challenge to develop alternative inhibitors. We synthesized a series of allophenylnorstatine-based peptidomimetics with various P<sub>3</sub>, P<sub>2</sub>, and P<sub>2</sub>́ moieties. The derivatives with P<sub>2</sub> tetrahydrofuranylglycine (Thfg) were found to be potent against wild type HIV-1 protease and the virus, leading to a highly potent compound <b>21f</b> (KNI-1657) against lopinavir/ritonavir- or darunavir-resistant strains. Co-crystal structures of <b>21f</b> and the wild-type protease revealed numerous key hydrogen bonding interactions with Thfg. These results suggest that the strategy to design allophenylnorstatine-based peptidomimetics combined with Thfg residue would be promising for generating candidates to overcome multidrug resistance

    Identification of Highly Potent Human Immunodeficiency Virus Type‑1 Protease Inhibitors against Lopinavir and Darunavir Resistant Viruses from Allophenylnorstatine-Based Peptidomimetics with P2 Tetrahydrofuranylglycine

    No full text
    The emergence of drug-resistant HIV from a widespread antiviral chemotherapy targeting HIV protease in the past decades is unavoidable and provides a challenge to develop alternative inhibitors. We synthesized a series of allophenylnorstatine-based peptidomimetics with various P<sub>3</sub>, P<sub>2</sub>, and P<sub>2</sub>́ moieties. The derivatives with P<sub>2</sub> tetrahydrofuranylglycine (Thfg) were found to be potent against wild type HIV-1 protease and the virus, leading to a highly potent compound <b>21f</b> (KNI-1657) against lopinavir/ritonavir- or darunavir-resistant strains. Co-crystal structures of <b>21f</b> and the wild-type protease revealed numerous key hydrogen bonding interactions with Thfg. These results suggest that the strategy to design allophenylnorstatine-based peptidomimetics combined with Thfg residue would be promising for generating candidates to overcome multidrug resistance

    Reduction of cardiac imaging tests during the COVID-19 pandemic: The case of Italy. Findings from the IAEA Non-invasive Cardiology Protocol Survey on COVID-19 (INCAPS COVID)

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    Background: In early 2020, COVID-19 massively hit Italy, earlier and harder than any other European country. This caused a series of strict containment measures, aimed at blocking the spread of the pandemic. Healthcare delivery was also affected when resources were diverted towards care of COVID-19 patients, including intensive care wards. Aim of the study: The aim is assessing the impact of COVID-19 on cardiac imaging in Italy, compare to the Rest of Europe (RoE) and the World (RoW). Methods: A global survey was conducted in May–June 2020 worldwide, through a questionnaire distributed online. The survey covered three periods: March and April 2020, and March 2019. Data from 52 Italian centres, a subset of the 909 participating centres from 108 countries, were analyzed. Results: In Italy, volumes decreased by 67% in March 2020, compared to March 2019, as opposed to a significantly lower decrease (p &lt; 0.001) in RoE and RoW (41% and 40%, respectively). A further decrease from March 2020 to April 2020 summed up to 76% for the North, 77% for the Centre and 86% for the South. When compared to the RoE and RoW, this further decrease from March 2020 to April 2020 in Italy was significantly less (p = 0.005), most likely reflecting the earlier effects of the containment measures in Italy, taken earlier than anywhere else in the West. Conclusions: The COVID-19 pandemic massively hit Italy and caused a disruption of healthcare services, including cardiac imaging studies. This raises concern about the medium- and long-term consequences for the high number of patients who were denied timely diagnoses and the subsequent lifesaving therapies and procedures
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