7,456 research outputs found
The Conserved G-Protein Coupled Receptor FSHR-1 Regulates Protective Host Responses to Infection and Oxidative Stress
The innate immune system’s ability to sense an infection is critical so that it can rapidly respond if pathogenic microorganisms threaten the host, but otherwise maintain a quiescent baseline state to avoid causing damage to the host or to commensal microorganisms. One important mechanism for discriminating between pathogenic and non-pathogenic bacteria is the recognition of cellular damage caused by a pathogen during the course of infection. InCaenorhabditis elegans, the conserved G-protein coupled receptor FSHR-1 is an important constituent of the innate immune response. FSHR-1 activates the expression of antimicrobial infection response genes in infected worms and delays accumulation of the ingested pathogenPseudomonas aeruginosa. FSHR-1 is central not only to the worm’s survival of infection by multiple pathogens, but also to the worm’s survival of xenobiotic cadmium and oxidative stresses. Infected worms produce reactive oxygen species to fight off the pathogens; FSHR-1 is required at the site of infection for the expression of detoxifying genes that protect the host from collateral damage caused by this defense response. Finally, the FSHR-1 pathway is important for the ability of worms to discriminate pathogenic from benign bacteria and subsequently initiate an aversive learning program that promotes selective pathogen avoidance
XMM instrument on-board software maintenance concept
While the pre-launch responsibility for the production, validation and maintenance of instrument on-board software traditionally lies with the experimenter, the post-launch maintenance has been the subject of ad hoc arrangements with the responsibility shared to different extent between the experimenter, ESTEC and ESOC. This paper summarizes the overall design and development of the instruments on-board software for the XMM satellite, and describes the concept adopted for the maintenance of such software post-launch. The paper will also outline the on-board software maintenance and validation facilities and the expected advantages to be gained by the proposed strategy. Conclusions with respect to adequacy of this approach will be presented as well as recommendations for future instrument on-board software developments
Effect of Cover Crops on Nitrogen Uptake, Soil Water Content and Biomass Production in a Short Rotation Poplar Plantation
The agricultural production of biomass for energy-giving uses is attracting increasing interest particularly in relation to the possibility of reducing the use of fossil fuels and thereby limiting the emission of greenhouse gases. However one of the barriers to wider development of biomass energy sources is the lack of information about the environmental impacts on the landscape of increasing production of biomass crops. In the first growth phases as in the subsequent harvesting stages, the risks of erosion can become considerable due to the absence of any sort of protective canopy. In this case resorting to the use of cover crops can represent a useful agronomic measure since it provides and maintains a suitable ground covering, above all in the winter months when leaf fall exposes the soil to rain action.
The aim of the present work was to evaluate some of the agronomic effects of the planting of two different species of cover crops, the legume Trifolium subterraneum L. and the grass Lolium perenne L. in a closely spaced forestry plantation
Charge carrier interaction with a purely electronic collective mode: Plasmarons and the infrared response of elemental bismuth
We present a detailed optical study of single crystal bismuth using infrared
reflectivity and ellipsometry. Colossal changes in the plasmon frequency are
observed as a function of temperature due to charge transfer between hole and
electron Fermi pockets. In the optical conductivity, an anomalous temperature
dependent mid-infrared absorption feature is observed. An extended Drude model
analysis reveals that it can be connected to a sharp upturn in the scattering
rate, the frequency of which exactly tracks the temperature dependent plasmon
frequency. We interpret this absorption and increased scattering as the first
direct optical evidence for a charge carrier interaction with a collective mode
of purely electronic origin; here electron-plasmon scattering. The observation
of a \emph{plasmaron} as such is made possible only by the unique coincidence
of various energy scales and exceptional properties of semi-metal bismuth.Comment: 4 pages, 4 figure
On the Mechanical Energy Involved in the Catastrophic Rupture of Liquid Hydrogen Tanks
Hydrogen can play a central role in the energy transition thanks to its unique properties. However, its low density is one of the main drawbacks. The liquefaction process can drastically increase its density up to virtually 71 kg m-3 at atmospheric pressure and -253°C (NIST, 2019). The safety knowledge gap on physical explosions is still broad in the case of liquid hydrogen (LH2). For instance, it is unclear what are the consequences yields as well as the probabilities of a catastrophic rupture of an LH2 tank. A boiling liquid expanding vapour explosion (BLEVE) might arise after this top event. In this case, the expansion of the compressed gaseous phase is followed by the flashing of a fraction of the liquid. Moreover, combustion may occur for hydrogen since it is highly flammable. This complex phenomenon was not widely explored for LH2 yet. This study focused on the physical explosion by also considering the combustion process. Many integral models were adopted to estimate the mechanical energy developed by the explosion. The tank pressure prior to the rupture was considered below the critical one (1.298 MPa (NIST, 2019)). It was assumed that both liquid and gaseous phases are present inside the tank. The influences of the filling degree of the tank (liquid level) and the temperatures of the liquid and gaseous phases on the explosion energy were analysed. The results were compared with the ones of a previous study where similar models were employed to estimate the mechanical energy of an LH2 tank with different initial conditions (Ustolin et al., 2020a). In particular, the effect of the combustion process on the explosion energy and shock wave overpressure was not accounted for. The aim of this study is to conduct a comparison between different models and assess which are the most and the least conservative. The outcomes of this work provide critical suggestions on the consequence analysis of cryogenic liquefied gas vessels explosions
Primary antiphospholipid syndrome during aromatase inhibitors therapy: A case report and review of the literature
RATIONALE: Aromatase inhibitors (AIs) are a class of drugs widely used in the treatment of estrogen sensitive breast and ovarian cancer which convert testosterone to estradiol and androstenedione to estrogen. The AIs of third generation, including anastrazole, letrozole and exemestane, have actually become the standard of care of estrogen-receptor-positive breast cancer in menopausal women and are recommended as adjuvant treatment after surgery in place of/or following tamoxifen. Their main side-effects include reduction in bone mineral density, occurrence of menopausal manifestations and development of musculoskeletal symptoms which are, usually, transient, but sometimes evolve into a typical form of arthritis, such as rheumatoid arthritis (RA). Recently, a pathogenic linkage with other autoimmunity diseases, such as Sjogren syndrome (SjS), anti-synthetase antibody syndrome (ASAS), systemic sclerosis (SS) and subacute cutaneous lupus erythematosus (SCLE), was also described. PATIENT CONCERNS: Here, we report the first case of a patient with primary antiphospholipid syndrome (APS) developed during treatment with anastrazole. DIAGNOSIS: The patient developed a sudden onset of speech disturbance and disorientation, due to ischemic lesions, after 6 months of AIs therapy and the laboratory examination showed the positivity of anti-Cardiolipin antibodies, anti-\u3b22 Glycoprotein 1 antibodies and Lupus Anticoagulant, so a certain diagnosis of APS was achieved. INTERVENTIONS: The patient was treated with warfarin associated to hydroxychloroquine and monthly cycles of low doses intravenous immunoglobulins. OUTCOMES: A good control of the disease was obtained despite the continuation of anastrazole; the patient's clinical and laboratory situation remained not modified after AIs withdrawal. LESSONS: We discussed the possible role of anastrazole treatment in inducing APS in our patient, reporting the available literature data about the association between AIs treatment and autoimmune diseases. Furthermore, we analyzed the mechanism of action of estrogens in the pathophysiology of autoimmune rheumatic disorder
Magnetic glassy phase in FeSeTe single crystals
The evolution of the magnetic order in FeSeTe crystals as a function of Se
content was investigated by means of ac/dc magnetometry and muon-spin
spectroscopy. Experimental results and self-consistent DFT calculations both
indicate that muons are implanted in vacant iron-excess sites, where they probe
a local field mainly of dipolar origin, resulting from an antiferromagnetic
(AFM) bicollinear arrangement of iron spins. This long-range AFM phase
disorders progressively with increasing Se content. At the same time all the
tested samples manifest a marked glassy character that vanishes for high Se
contents. The presence of local electronic/compositional inhomogeneities most
likely favours the growth of clusters whose magnetic moment "freezes" at low
temperature. This glassy magnetic phase justifies both the coherent muon
precession seen at short times in the asymmetry data, as well as the glassy
behaviour evidenced by both dc and ac magnetometry.Comment: Approved for publication in J. Phys.: Condens. Matte
In-plane optical spectral weight transfer in optimally doped BiSrCaCuO
We examine the redistribution of the in-plane optical spectral weight in the
normal and superconducting state in tri-layer \bbb (Bi2223) near optimal doping
( = 110 K) on a single crystal via infrared reflectivity and spectroscopic
ellipsometry. We report the temperature dependence of the low-frequency
integrated spectral weight for different values of the cutoff
energy . Two different model-independent analyses consistently show
that for = 1 eV, which is below the charge transfer gap,
increases below , implying the lowering of the kinetic
energy of the holes. This is opposite to the BCS scenario, but it follows the
same trend observed in the bi-layer compound \bb (Bi2212). The size of this
effect is larger in Bi2223 than in Bi2212, approximately scaling with the
critical temperature. In the normal state, the temperature dependence of
is close to up to 300 K
Magnetic hour-glass dispersion and its relation to high-temperature superconductivity in iron-tuned FeTeSe
High-temperature superconductivity remains arguably the largest outstanding
enigma of condensed matter physics. The discovery of iron-based
high-temperature superconductors has renewed the importance of understanding
superconductivity in materials susceptible to magnetic order and fluctuations.
Intriguingly they show magnetic fluctuations reminiscent of the superconducting
(SC) cuprates, including a 'resonance' and an 'hour-glass' shaped dispersion,
which provide an opportunity to new insight to the coupling between spin
fluctuations and superconductivity. Here we report inelastic neutron scattering
data on FeTeSe using excess iron concentration to tune
between a SC () and a non-SC () ground states. We find
incommensurate spectra in both samples but discover that in the one that
becomes SC, a constriction towards a commensurate hourglass shape develop well
above . Conversely a spin-gap and concomitant spectral weight shift happen
below . Our results imply that the hourglass shaped dispersion is most
likely a pre-requisite for superconductivity, whereas the spin-gap and shift of
spectral weight are consequences of superconductivity. We explain this
observation by pointing out that an inwards dispersion towards the commensurate
wave-vector is needed for the opening of a spin gap to lower the magnetic
exchange energy and hence provide the necessary condensation energy for the SC
state to emerge
Recent outburst of the young star V1180 Cas
We report on the ongoing outburst of the young variable V1180 Cas, which is
known to display characteristics in common with EXor eruptive variables. We
present results that support the scenario of an accretion-driven nature of the
brightness variations of the object and provide the first evidence of jet
structures around the source. We monitored the recent flux variations of the
target in the Rc, J, H, and K bands. New optical and near-IR spectra taken
during the current high state of V1180 Cas are presented, in conjunction with
H2 narrow-band imaging of the source. Observed near-IR colour variations are
analogous to those observed in EXors and consistent with excess emission
originating from an accretion event. The spectra show numerous emission lines,
which indicates accretion, ejection of matter, and an active disc. Using
optical and near-IR emission features we derive a mass accretion rate of ~3 E-8
Msun/yr, which is an order of magnitude lower than previous estimates. In
addition, a mass loss rate of ~4 E-9 and ~4 E-10 Msun/yr are estimated from
atomic forbidden lines and H2, respectively. Our H2 imaging reveals two bright
knots of emission around the source and the nearby optically invisible star
V1180 Cas B, clearly indicative of mass-loss phenomena. Higher resolution
observations of the detected jet will help to clarify whether V1180 Cas is the
driving source and to determine the relation between the observed knots.Comment: Accepted as Letter in A&A; 4 pages, 3 figure
- …