2,200 research outputs found

    Активація м’язів плечового пояса та плеча людини в перебігу двосуглобових рухів руки, що виконуються при дії зовнішніх навантажень протилежних напрямів

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    У дослідах на чотирьох добровольцях досліджувалася координація центральних рухових команд (ЦРК), що керували повільними двосуглобовими рухами руки в горизонтальній площині. Як кореляти інтенсивності таких команд розглядались поточні амплітуди ЕМГ, відведених від шести м’язів плечового пояса і плеча й підданих повному випрямленню та низькочастотній фільтрації. Зокрема, досліджували залежність координації ЦРК від напрямку зовнішньої сили, яка прикладалася до дистальної частини передпліччя. Як виявилося, координація ЦРК істотно залежить від напрямку сили, що згинає ліктьовий суглоб. Згідно з результатами дослідження, ЕМГ певних м’язів у разі виконання двосуглобового руху може бути представлена як лінійна комбінація ЕМГ, зареєстрованих у перебігу послідовних односуглобових рухів в умовах пересування референтної точки кисті в ту ж саму точку операційного простору, що й при двосуглобовому русі. Отримані дані можуть вважатися підтвердженням принципу суперпозиції елементарних ЦРК під час виконання складних рухів кінцівок

    High-level diversity of tailed phages, eukaryote-associated viruses, and virophage-like elements in the metaviromes of Antarctic soils

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    The metaviromes of two distinct Antarctic hyperarid desert soil communities have been characterized. Hypolithic communities, cyanobacterium-dominated assemblages situated on the ventral surfaces of quartz pebbles embedded in the desert pavement, showed higher virus diversity than surface soils, which correlated with previous bacterial community studies. Prokaryotic viruses (i.e., phages) represented the largest viral component (particularly Mycobacterium phages) in both habitats, with an identical hierarchical sequence abundance of families of tailed phages (Siphoviridae>Myoviridae>Podoviridae). No archaeal viruses were found. Unexpectedly, cyanophages were poorly represented in both metaviromes and were phylogenetically distant from currently characterized cyanophages. Putative phage genomes were assembled and showed a high level of unaffiliated genes, mostly from hypolithic viruses. Moreover, unusual gene arrangements in which eukaryotic and prokaryotic virus-derived genes were found within identical genome segments were observed. Phycodnaviridae and Mimiviridae viruses were the second-mostabundant taxa and more numerous within open soil. Novel virophage-like sequences (within the Sputnik clade) were identified. These findings highlight high-level virus diversity and novel species discovery potential within Antarctic hyperarid soils and may serve as a starting point for future studies targeting specific viral groups.IS

    Coupled-resonator optical waveguides: Q-factor and disorder influence

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    Coupled resonator optical waveguides (CROW) can significantly reduce light propagation pulse velocity due to pronounced dispersion properties. A number of interesting applications have been proposed to benefit from such slow-light propagation. Unfortunately, the inevitable presence of disorder, imperfections, and a finite Q value may heavily affect the otherwise attractive properties of CROWs. We show how finite a Q factor limits the maximum attainable group delay time; the group index is limited by Q, but equally important the feasible device length is itself also limited by damping resulting from a finite Q. Adding the additional effects of disorder to this picture, limitations become even more severe due to destructive interference phenomena, eventually in the form of Anderson localization. Simple analytical considerations demonstrate that the maximum attainable delay time in CROWs is limited by the intrinsic photon lifetime of a single resonator.Comment: Accepted for Opt. Quant. Electro

    Identification of Peptide Ligands for Targeting to the Blood-Brain Barrier

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    PurposeTransport of drugs to the brain is limited by the blood-brain barrier. New, specific brain endothelium ligands can facilitate brain-specific delivery of drugs. MethodsWe used phage display in an in situ brain perfusion model to screen for new brain endothelium peptide ligands. ResultsTwo phage clones, displaying 15 amino acid-peptides (GLA and GYR) that were selected for brain binding in the mouse model, showed significant binding to human brain endothelium (hCMEC/D3), compared to a random control phage. This binding was not seen for other human endothelial cells (HUVEC). Binding to hCMEC/D3 cells was dose dependent. When phage GLA and GYR were individually perfused through the murine brain, their ability to bind to the brain was 6-fold (GLA) and 5-fold (GYR) higher than the control phage. When compared to lung perfusion, phage showed an 8.5-fold (GYR) and 48-fold (GLA) preference for brain over lung compared to the control. ConclusionsThese results indicate that two new peptide ligands have been identified that may be used for specific targeting of drugs to the blood-brain barrier

    Dust-enshrouded Asymptotic Giant Branch Stars in the Solar Neighbourhood

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    A study is made of a sample of 58 dust-enshrouded Asymptotic Giant Branch (AGB) stars (including 2 possible post AGB stars), of which 27 are carbon-rich and 31 are oxygen-rich. These objects were originally identified by Jura & Kleinmann as nearby (within about 1 kpc of the sun) AGB stars with high mass-loss rates, greater than 1E-6 solar masses per year. Ground-based near-infrared photometry, data obtained by IRAS and kinematic data from the literature are combined to investigate the properties of these stars. The light amplitude in the near-infrared is found to be correlated with period, and this amplitude decreases with increasing wavelength. Statistical tests show that there is no reason to suspect any difference in the period distributions of the carbon- and oxygen-rich stars for periods less than 1000 days, and no carbon-rich star has a period longer than 1000 days. The colours are consistent with those of cool stars with evolved circumstellar dust-shells. Luminosities and distances are estimated using a period-luminosity relation. Mass-loss rates, estimated from the 60 micron fluxes, show a correlation with pulsation period and is tightly correlated with the K-[12] colour. The kinematics and scale-height of the sample shows that the sources with periods less than 1000 days must have low mass main-sequence progenitors. It is argued that the three oxygen-rich stars with periods over 1000 days probably had intermediate mass main-sequence progenitors with remaining stars having an average progenitor mass of about 1.3 solar masses. The average lifetime of stars in this phase is estimated to be about 4.0E4 years, indicating they will undergo at most one more thermal pulse before leaving the AGB.Comment: 27 pages, 20 figures, accepted for MNRA

    Niche-dependent genetic diversity in Antarctic metaviromes

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    The metaviromes from 2 different Antarctic terrestrial soil niches have been analyzed. Both hypoliths (microbial assemblages beneath transluscent rocks) and surrounding open soils showed a high level diversity of tailed phages, viruses of algae and amoeba, and virophage sequences. Comparisons of other global metaviromes with the Antarctic libraries showed a niche-dependent clustering pattern, unrelated to the geographical origin of a given metavirome. Within the Antarctic open soil metavirome, a putative circularly permuted, »42kb dsDNA virus genome was annotated, showing features of a temperate phage possessing a variety of conserved protein domains with no significant taxonomic affiliations in current databases.National Research Foundation (South Africa) and the Genomics Research Institute of the University of Pretoria (South Africa).http://www.tandfonline.com/loi/kbac202015-12-31hb201

    Simulations of idealised 3D atmospheric flows on terrestrial planets using LFRic-Atmosphere

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    We demonstrate that LFRic-Atmosphere, a model built using the Met Office's GungHo dynamical core, is able to reproduce idealised large-scale atmospheric circulation patterns specified by several widely-used benchmark recipes. This is motivated by the rapid rate of exoplanet discovery and the ever-growing need for numerical modelling and characterisation of their atmospheres. Here we present LFRic-Atmosphere's results for the idealised tests imitating circulation regimes commonly used in the exoplanet modelling community. The benchmarks include three analytic forcing cases: the standard Held-Suarez test, the Menou-Rauscher Earth-like test, and the Merlis-Schneider Tidally Locked Earth test. Qualitatively, LFRic-Atmosphere agrees well with other numerical models and shows excellent conservation properties in terms of total mass, angular momentum and kinetic energy. We then use LFRic-Atmosphere with a more realistic representation of physical processes (radiation, subgrid-scale mixing, convection, clouds) by configuring it for the four TRAPPIST-1 Habitable Atmosphere Intercomparison (THAI) scenarios. This is the first application of LFRic-Atmosphere to a possible climate of a confirmed terrestrial exoplanet. LFRic-Atmosphere reproduces the THAI scenarios within the spread of the existing models across a range of key climatic variables. Our work shows that LFRic-Atmosphere performs well in the seven benchmark tests for terrestrial atmospheres, justifying its use in future exoplanet climate studies.Comment: 34 pages, 9(12) figures; Submitted to Geoscientific Model Development; Comments are welcome (see Discussion tab on the journal's website: https://egusphere.copernicus.org/preprints/2023/egusphere-2023-647

    Treatment outcome definitions in nontuberculous mycobacterial pulmonary disease: an NTM-NET consensus statement

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    Nontuberculous mycobacterial pulmonary diseases (NTM-PD) are increasingly recognised as opportunistic infections of humans. These chronic pulmonary infections have two main presentations. The first is a fibro-cavitary disease, that occurs in patients with pre-existing pulmonary diseases, such as chronic obstructive pulmonary disease, bronchiectasis, previous tuberculosis or other structural lung disease. The second presentation is a nodular- bronchiectatic disease of primarily the lingula and middle lobe that tends to affect a middle- aged and elderly female population [1]. Treatment of NTM-PD requires long-term administration of complex multidrug therapies that are species-specific. Currently recommended regimens are supported by a very limited evidence base [2, 3]. The increasing incidence of NTM-PD has sparked increased interest in performing prospective randomised clinical trials [4]. One of the drawbacks of the existing case series and clinical trials is that they have applied different outcome measures [5]. This hampers meta-analyses, which are important in these still understudied infectious diseases. To enhance the quality and interpretability of the results of future trials and retrospective cohort studies, we aimed to formulate clear and broadly acceptable outcome definitions for NTM-PD treatment

    The metamorphosis of SN1998bw

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    We present and discuss the photometric and spectroscopic evolution of the peculiar SN1998bw, associated with GRB980425, through an analysis of optical and near IR data collected at ESO-La Silla. The spectroscopic data, spanning the period from day -9 to day +376 (relative to B maximum), have shown that this SN was unprecedented, although somewhat similar to SN1997ef. Maximum expansion velocities as high as 3x10^4 km/s to some extent mask its resemblance to other Type Ic SNe. At intermediate phases, between photospheric and fully nebular, the expansion velocities (~10^4 km/s) remained exceptionally high compared to those of other recorded core-collapse SNe at a similar phase. The mild linear polarization detected at early epochs suggests the presence of asymmetry in the emitting material. The degree of asymmetry, however, cannot be decoded from these measurements alone. The HeI 1.083 mu and 2.058 mu lines are identified and He is suggested to lie in an outer region of the envelope. The temporal behavior of the fluxes and profiles of emission lines of MgI]4571A, [OI]6300,6364A and a feature ascribed to Fe are traced to stimulate future modeling work.Comment: 32 pages, 19 figures; ps file including figures at http://www.eso.org/~fpatat/sn98b
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