711 research outputs found
The interferon-induced exonuclease ISG20 exerts antiviral activity through upregulation of type I interferon response proteins
The host immune responses to infection lead to the production of type I interferon (IFN), and the upregulation of interferon-stimulated genes (ISGs) reduces virus replication and virus dissemination within a host. Ectopic expression of the interferon-induced 20-kDa exonuclease ISG20 suppressed replication of chikungunya virus and Venezuelan equine encephalitis virus, two mosquito-vectored RNA alphaviruses. Since the replication of alphavirus genomes occurs exclusively in the cytoplasm, the mechanism of nucleus-localized ISG20 inhibition of replication is unclear. In this study, we determined that ISG20 acts as a master regulator of over 100 genes, many of which are ISGs. Specifically, ISG20 upregulated IFIT1 genes and inhibited translation of the alphavirus genome. Furthermore, IFIT1-sensitive alphavirus replication was increased in Isg20−/− mice compared to the replication of wild-type viruses but not in cells ectopically expressing ISG20. We propose that ISG20 acts as an indirect regulator of RNA virus replication in the cytoplasm through the upregulation of many other ISGs.Type I interferon (IFN)-stimulated genes (ISGs) have critical roles in inhibiting virus replication and dissemination. Despite advances in understanding the molecular basis of ISG restriction, the antiviral mechanisms of many remain unclear. The 20-kDa ISG ISG20 is a nuclear 3′–5′ exonuclease with preference for single-stranded RNA (ssRNA) and has been implicated in the IFN-mediated restriction of several RNA viruses. Although the exonuclease activity of ISG20 has been shown to degrade viral RNA in vitro, evidence has yet to be presented that virus inhibition in cells requires this activity. Here, we utilized a combination of an inducible, ectopic expression system and newly generated Isg20−/− mice to investigate mechanisms and consequences of ISG20-mediated restriction. Ectopically expressed ISG20 localized primarily to Cajal bodies in the nucleus and restricted replication of chikungunya and Venezuelan equine encephalitis viruses. Although restriction by ISG20 was associated with inhibition of translation of infecting genomic RNA, degradation of viral RNAs was not observed. Instead, translation inhibition of viral RNA was associated with ISG20-induced upregulation of over 100 other genes, many of which encode known antiviral effectors. ISG20 modulated the production of IFIT1, an ISG that suppresses translation of alphavirus RNAs. Consistent with this observation, the pathogenicity of IFIT1-sensitive alphaviruses was increased in Isg20−/− mice compared to that of wild-type viruses but not in cells ectopically expressing ISG20. Our findings establish an indirect role for ISG20 in the early restriction of RNA virus replication by regulating expression of other ISGs that inhibit translation and possibly other activities in the replication cycle
1.6 GHz Low-Power Cross-Correlator System Enabling Geostationary Earth Orbit Aperture Synthesis
We present a 64-channel cross-correlator system for space-borne synthetic aperture imaging. Two different types of ASICs were developed to fit into this system: An 8-channel comparator ASIC implemented in a 130 nm SiGe BiCMOS process technology performs A/D conversion, while a single 64-channel digital cross-correlator ASIC implemented in a 65 nm CMOS process performs the signal processing. The digital ASIC handles 2016 cross-correlations at up to 3.6 GS/s and has a power dissipation of only 0.13 mW/correlation/GHz at a supply voltage of 1 V. The comparator ASIC can handle sample rates of at least 4.5 GS/s with a power dissipation of 47 mW/channel or 1 GS/s with a power dissipation of 17 mW/channel. The assembled system consists of a single board measuring a mere 136 x 136 mm(2) and weighing only 135 g. The assembled system demonstrates crosstalk of 0.04% between neighboring channels and stability of 800 s. We provide ASIC and system-board measurement results that demonstrate that aperture synthesis can be a viable approach for Earth observation from a geostationary Earth orbit
Allometric trajectories of body and head morphology in three sympatric Arctic charr (Salvelinus alpinus (L.)) morphs
A study of body and head development in three sympatric reproductively isolated Arctic charr (Salvelinus alpinus (L.)) morphs from a subarctic lake (Skogsfjordvatn, northern Norway) revealed allometric trajectories that resulted in morphological differences. The three morphs were ecologically assigned to a littoral omnivore, a profundal benthivore and a profundal piscivore, and this was confirmed by genetic analyses (microsatellites). Principal component analysis was used to identify the variables responsible for most of the morphological variation of the body and head shape. The littoral omnivore and the profundal piscivore morph had convergent allometric trajectories for the most important head shape variables, developing bigger mouths and relatively smaller eyes with increasing head size. The two profundal morphs shared common trajectories for the variables explaining most of the body and head shape variation, namely head size relative to body size, placement of the dorsal and pelvic fins, eye size and mouth size. In contrast, the littoral omnivore and the profundal benthivore morphs were not on common allometric trajectories for any of the examined variables. The findings suggest that different selective pressures could have been working on traits related to their trophic niche such as habitat and diet utilization of the three morphs, with the two profundal morphs experiencing almost identical environmental conditions
Navigating a Pandemic: A Qualitative Study of Knowledge, Sources of Information, and COVID-19-Related Precautions Taken by HBCU Students
The coronavirus (COVID-19) has spread quickly across the nation with a disproportionate impact on Black Americans. Many college-aged students receive their COVID-19-related information through social media and television even though research suggests that social media sources are more likely to be incorrect. Some students report trusting these sources over government sources such as the CDC and WHO. The purpose of this study was to understand Historically Black College and University (HBCU) students’ COVID-19 knowledge, sources of information, and planned precautions. There were 21 in-depth interviews conducted with students attending a large southern HBCU during Spring 2020. Themes regarding knowledge included the following: it is a flu-like condition, it has international roots, there is inaccurate and changing information, and it is a pandemic. Themes regarding sources included: the news, US government and related officials, social media, interactions with family, and other social interactions. Themes regarding severity included the following: statistics, a distrust for hospital reporting, a belief that COVID-19 deaths were conflated with baseline health, peer influence, and familial influence. Themes regarding precautions included the following: proper mask use, hand washing/ sanitizing, avoiding large crowds/small crowds only, physical distancing, COVID-19 testing/symptom monitoring, and COVID-19 vaccination
Wandering behaviour prevents inter and intra oceanic speciation in a coastal pelagic fish
Small pelagic fishes have the ability to disperse over long distances and may present complex evolutionary histories. Here, Old World Anchovies (OWA) were used as a model system to understand genetic patterns and connectivity of fish between the Atlantic and Pacific basins. We surveyed 16 locations worldwide using mtDNA and 8 microsatellite loci for genetic parameters, and mtDNA (cyt b; 16S) and nuclear (RAG1; RAG2) regions for dating major lineage-splitting events within Engraulidae family. The OWA genetic divergences (0-0.4%) are compatible with intra-specific divergence, showing evidence of both ancient and contemporary admixture between the Pacific and Atlantic populations, enhanced by high asymmetrical migration from the Pacific to the Atlantic. The estimated divergence between Atlantic and Pacific anchovies (0.67 [0.53-0.80] Ma) matches a severe drop of sea temperature during the Gunz glacial stage of the Pleistocene. Our results support an alternative evolutionary scenario for the OWA, suggesting a coastal migration along south Asia, Middle East and eastern Africa continental platforms, followed by the colonization of the Atlantic via the Cape of the Good Hope.Portuguese Foundation for Science & Technology (FCT) [SFRH/BD/36600/2007]; FCT [UID/MAR/04292/2013, SFRH/BPD/65830/2009]; FCT strategic plan [UID/Multi/04326/2013]info:eu-repo/semantics/publishedVersio
A mixed methods approach to evaluating community drug distributor performance in the control of neglected tropical diseases
BACKGROUND: Trusted literate, or semi-literate, community drug distributors (CDDs) are the primary implementers in integrated preventive chemotherapy (IPC) programmes for Neglected Tropical Disease (NTD) control. The CDDs are responsible for safely distributing drugs and for galvanising communities to repeatedly, often over many years, receive annual treatment, create and update treatment registers, monitor for side-effects and compile treatment coverage reports. These individuals are 'volunteers' for the programmes and do not receive remuneration for their annual work commitment. METHODS: A mixed methods approach, which included pictorial diaries to prospectively record CDD use of time, structured interviews and focus group discussions, was used to triangulate data on how 58 CDDs allocated their time towards their routine family activities and to NTD Programme activities in Uganda. The opportunity costs of CDD time were valued, performance assessed by determining the relationship between time and programme coverage, and CDD motivation for participating in the programme was explored. RESULTS: Key findings showed approximately 2.5 working weeks (range 0.6-11.4 working weeks) were spent on NTD Programme activities per year. The amount of time on NTD control activities significantly increased between the one and three deliveries that were required within an IPC campaign. CDD time spent on NTD Programme activities significantly reduced time available for subsistence and income generating engagements. As CDDs took more time to complete NTD Programme activities, their treatment performance, in terms of validated coverage, significantly decreased. Motivation for the programme was reported as low and CDDs felt undervalued. CONCLUSIONS: CDDs contribute a considerable amount of opportunity cost to the overall economic cost of the NTD Programme in Uganda due to the commitment of their time. Nevertheless, programme coverage of at least 75Â %, as required by the World Health Organisation, is not being achieved and vulnerable individuals may not have access to treatment as a consequence of sub-optimal performance by the CDDs due to workload and programmatic factors
Geoantineutrino Spectrum, 3He/4He-ratio Distribution in the Earth's Interior and Slow Nuclear Burning on the Boundary of the Liquid and Solid Phases of the Earth's Core
The description problem of geoantineutrino spectrum and reactor antineutrino
experimental spectrum in KamLAND, which takes place for antineutrino energy
\~2.8 MeV, and also the experimental results of the interaction of uranium
dioxide and carbide with iron-nickel and silicaalumina melts at high pressure
(5-10 GP?) and temperature (1600-2200C) have motivated us to consider the
possible consequences of the assumption made by V.Anisichkin and coauthors that
there is an actinid shell on boundary of liquid and solid phases of the Earth's
core. We have shown that the activation of a natural nuclear reactor operating
as the solitary waves of nuclear burning in 238U- and/or 232Th-medium (in
particular, the neutron- fission progressive wave of Feoktistov and/or
Teller-Ishikawa-Wood) can be such a physical consequence. The simplified model
of the kinetics of accumulation and burnup in U-Pu fuel cycle of Feoktistov is
developed. The results of the numerical simulation of neutron-fission wave in
two-phase UO2/Fe medium on a surface of the Earth's solid core are presented.
The georeactor model of 3He origin and the 3He/4He-ratio distribution in the
Earth's interior is offered. It is shown that the 3He/4He ratio distribution
can be the natural quantitative criterion of georeactor thermal power. On the
basis of O'Nions-Evensen-Hamilton geochemical model of mantle differentiation
and the crust growth supplied by actinid shell on the boundary of liquid and
solid phases of the Earth's core as a nuclear energy source (georeactor with
power of 30 TW), the tentative estimation of geoantineutrino intensity and
geoantineutrino spectrum on the Earth surface are given.Comment: 28 pages, 12 figures. Added text, formulas, figures and references.
Corrected equations. Changed content of some section
Energy absorption buildup factors of human organs and tissues at energies and penetration depths relevant for radiotherapy and diagnostics
Immunization programs to support primary health care and achieve universal health coverage
Gains in immunization coverage and delivery of primary health care service have stagnated in recent years. Remaining gaps in service coverage reflect multiple underlying reasons that may be amenable to improved health system design. Immunization systems and other primary health care services can be mutually supportive, for improved service delivery and for strengthening of Universal Health Coverage. Improvements require that dynamic and multi-faceted barriers and risks be addressed. These include workforce availability, quality data systems and use, leadership and management that is innovative, flexible, data driven and responsive to local needs. Concurrently, improvements in procurement, supply chain, logistics and delivery systems, and integrated monitoring of vaccine coverage and epidemiological disease surveillance with laboratory systems, and vaccine safety will be needed to support community engagement and drive prioritized actions and communication. Finally, political will and sustained resource commitment with transparent accountability mechanisms are required. The experience of the impact of COVID-19 pandemic on essential PHC services and the challenges of vaccine roll-out affords an opportunity to apply lessons learned in order to enhance vaccine services integrated with strong primary health care services and universal health coverage across the life course
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