100 years after the infamous “Spanish flu” pandemic, the 2017–2018 flu season has been severe, with numerous infections worldwide. In between, there have been continuous, relentless attacks from ...(re-)emerging viruses. To fully understand viral pathogenesis and develop effective medical countermeasures, we must strengthen current surveillance and basic research efforts.
100 years after the infamous “Spanish flu” pandemic, the 2017–2018 flu season has been severe, with numerous infections worldwide. In between, there have been continuous, relentless attacks from (re-)emerging viruses. To fully understand viral pathogenesis and develop effective medical countermeasures, we must strengthen current surveillance and basic research efforts.
A modified distinct element Voronoi method, which we refer to as “Trigon” logic, is proposed for use in both two and three-dimensional modelling. A rock material is represented by an assembly of ...triangular (in 2D) or tetrahedral (in 3D) blocks bonded through their contacts. To evaluate the ability of the proposed Trigon logic in simulating brittle fracture, a series of unconfined and confined compression and Brazilian tests is performed illustrating the sample failure mechanisms under two and three dimensional conditions. Typical failure fracture patterns (damage) experienced by brittle rock are explicitly simulated including axial tensile failure under unconfined compression, shear failure under confined compression, and tensile crack extension during indirect tension (Brazilian) testing. A ‘damage parameter’ D and a ‘damage intensity’ D21 measure are proposed to allow the evaluation of the simulated rock damage in a more quantitative manner. At the mine opening scale, the process of roof shear failure is successfully captured using the Trigon logic. In comparison with the conventional Voronoi model, the proposed Trigon model is less mesh-sensitive and predicts both a more realistic friction angle and failure pattern under varied loading conditions.
•Develop a novel UDEC ‘Trigon’ logic to explicitly simulate brittle fracture in both 2 and 3 dimensions.•Proposed a ‘damage parameter’ to quantitatively evaluate simulated rock damage.•The ‘Trigon’ logic can capture various fracture patterns under different loading conditions.
Super-spreading occurs when a single patient infects a disproportionate number of contacts. The 2015 MERS-CoV, 2003 SARS-CoV, and to a lesser extent 2014–15 Ebola virus outbreaks were driven by ...super-spreaders. We summarize documented super-spreading in these outbreaks, explore contributing factors, and suggest studies to better understand super-spreading.
Super-spreading occurs when a single patient infects a disproportionate number of contacts. The 2015 MERS-CoV, 2003 SARS-CoV, and to a lesser extent 2014–15 Ebola virus outbreaks were driven by super-spreaders. We summarize documented super-spreading in these outbreaks, explore contributing factors, and suggest studies to better understand super-spreading.
The coronavirus disease 2019 (COVID-19) pandemic continues worldwide with many variants arising, some of which are variants of concern (VOCs). A recent VOC, omicron (B.1.1.529), which obtains a large ...number of mutations in the receptor-binding domain (RBD) of the spike protein, has risen to intense scientific and public attention. Here, we studied the binding properties between the human receptor ACE2 (hACE2) and the VOC RBDs and resolved the crystal and cryoelectron microscopy structures of the omicron RBD-hACE2 complex as well as the crystal structure of the delta RBD-hACE2 complex. We found that, unlike alpha, beta, and gamma, omicron RBD binds to hACE2 at a similar affinity to that of the prototype RBD, which might be due to compensation of multiple mutations for both immune escape and transmissibility. The complex structures of omicron RBD-hACE2 and delta RBD-hACE2 reveal the structural basis of how RBD-specific mutations bind to hACE2.
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•Omicron, delta, and prototype SARS-CoV-2 RBDs show similar binding strength to hACE2•The complexes of SARS-CoV-2-RBD with hACE2 for omicron and delta variants were resolved•The roles of key residues in the omicron RBD for receptor recognition were identified
Structural analysis of the complexes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RBD with the human ACE2 receptor for omicron and delta reveals variant-specific binding features.
Family involvement in management (FIM) attracts much scholarly attention in the field of family business but reveals conflicting performance implications. With the contradictions in mind, this paper ...raises and answers two research questions. First, how does FIM affect firm performance? Second, is the relationship between FIM and firm performance contingent on a firm's goals? To address these research questions, the study uses 158 family firms in China as a context in which to examine the role of family in business performance given the country's strong familial culture. Results show that while FIM has no direct effect on performance, a firm's family-longevity goals positively moderate the relationship between FIM and performance. Specifically, the relationship between FIM and performance is more positive when a firm's support for family-longevity goals is higher versus lower. The paper concludes with the implications of the results and the suggestions for future research.
Many breakthroughs in the laboratories often do not bridge the gap between research and commercialization. However, silicon photonics bucked the trend, with industry observers estimating the ...commercial market to close in on a billion dollars in 2020 <xref ref-type="bibr" rid="ref45">45 . Silicon photonics leverages the billions of dollars and decades of research poured into silicon semiconductor device processing to enable high yield, robust processing, and most of all, low cost. Silicon is also a good optical material, with transparency in the commercially important infrared wavelength bands, and is a suitable platform for large-scale photonic integrated circuits. Silicon photonics is therefore slated to address the world's ever-increasing needs for bandwidth. It is part of an emerging ecosystem which includes designers, foundries, and integrators. In this paper, we review most of the foundries that presently enable silicon photonics integrated circuits fabrication. Some of these are pilot lines of major research institutes, and others are fully commercial pure-play foundries. Since silicon photonics has been commercially active for some years, foundries have released process design kits (PDK) that contain a standard device library. These libraries represent optimized and well-tested photonic elements, whose performance reflects the stability and maturity of the integration platforms. We will document the early works in silicon photonics, as well as its commercial status. We will provide a comprehensive review of the development of silicon photonics and the foundry services which enable the productization, including various efforts to develop and release PDK devices. In this context, we will report the long-standing efforts and contributions that previously IME/A * STAR and now AMF has dedicated to accelerating this journey.
Influenza and the live poultry trade Gao, George F
Science (American Association for the Advancement of Science),
04/2014, Volume:
344, Issue:
6181
Journal Article
Peer reviewed
Live poultry trade at local markets has long been a part of China's national identity. From small villages to big cities, the gathering and selling of different birds in this vibrant atmosphere is at ...the heart of the country's cuisine culture. Unfortunately, the backdrop to this tradition has changed. Last year, the H7N9 virus, a new strain of influenza A, jumped from birds to humans, causing 144 cases of human infection and 47 deaths in China. Now a second wave of this flu is coursing through the country, with 258 confirmed cases and 99 deaths as of 8 April 2014. Scientific evidence points to a connection between the conditions at these live markets and the spread of flu, suggesting that until other means are found to prevent the transmission of or effectively treat the illness, China must shut down live poultry markets to prevent further spread of the virus and a possible global pandemic.
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