203 research outputs found
The Phase Diagram of Scalar Field Theory on the Fuzzy Disc
Using a recently developed bootstrapping method, we compute the phase diagram
of scalar field theory on the fuzzy disc with quartic even potential. We find
three distinct phases with second and third order phase transitions between
them. In particular, we find that the second order phase transition happens
approximately at a fixed ratio of the two coupling constants defining the
potential. We compute this ratio analytically in the limit of large coupling
constants. Our results qualitatively agree with previously obtained numerical
results.Comment: 1+17 pages, v2: typos fixed, published versio
Mixed Matrix Membranes based on PPO and graphene for gas separation
Novel composite Mixed Matrix Membranes (MMM) were fabricated by dispersion of different loadings of graphene nanoparticles (from 0.3 to 15 % weight percentage) in a dense permeable glassy polymer, poly (2,6-dimethyl-1,4-phenylene oxide), PPO, by
solvent casting procedure. The permeability, selectivity and diffusivity of helium, nitrogen and carbon dioxide have been measured at two different temperatures, 35° and 65°C and the effect of graphene loading was studied. (R. Rea et al. 2018)
Permeability and Selectivity of PPO/Graphene Composites as Mixed Matrix Membranes for CO2 Capture and Gas Separation
We fabricated novel composite (mixed matrix) membranes based on a permeable glassy
polymer, Poly(2,6-dimethyl-1,4-phenylene oxide) (PPO), and variable loadings of few-layer graphene,
to test their potential in gas separation and CO2 capture applications. The permeability, selectivity
and diffusivity of different gases as a function of graphene loading, from 0.3 to 15 wt %, was measured
at 35 and 65 \u25e6C. Samples with small loadings of graphene show a higher permeability and
He/CO2 selectivity than pure PPO, due to a favorable effect of the nanofillers on the polymer
morphology. Higher amounts of graphene lower the permeability of the polymer, due to the
prevailing effect of increased tortuosity of the gas molecules in the membrane. Graphene also
allows dramatically reducing the increase of permeability with temperature, acting as a \u201cstabilizer\u201d
for the polymer matrix. Such effect reduces the temperature-induced loss of size-selectivity for He/N2
and CO2/N2, and enhances the temperature-induced increase of selectivity for He/CO2. The study
confirms that, as observed in the case of other graphene-based mixed matrix glassy membranes,
the optimal concentration of graphene in the polymer is below 1 wt %. Below such threshold,
the morphology of the nanoscopic filler added in solution affects positively the glassy chains packing,
enhancing permeability and selectivity, and improving the selectivity of the membrane at increasing
temperatures. These results suggest that small additions of graphene to polymers can enhance their
permselectivity and stabilize their propertie
Renal Tubular Acidosis in Pregnant Critically Ill COVID-19 Patients: A Secondary Analysis of a Prospective Cohort
Background: Renal tubular acidosis (RTA) is an extremely rare cause of metabolic acidosis (10 in 100,000). RTA has been linked neither to pregnancy nor to severe coronavirus disease 2019 (COVID-19). The purpose of this study was to analyze the prevalence and clinical course of normal anion gap metabolic acidosis in critically ill pregnant COVID-19 patients and to compare them to an age-matched nonpregnant female patient cohort. Methods: Secondary analysis was conducted on a prospective observational cohort of critically ill patients suffering from COVID-19 consecutively admitted to a tertiary intensive care unit (ICU) between February 2020 and April 2021. Results: A total of 321 COVID-19 patients required admission to the ICU; 95 (30%) were female, and 18 (19%) were of childbearing age. Seven of eight (88%) pregnant women (all in the last trimester) required advanced respiratory support due to COVID-19. The estimated glomerular filtration rate was 135 (123â158) mL/min/m body surface area, and six pregnant women (86%) were diagnosed with a normal, respiratory compensated, anion gap metabolic acidosis (pH 7.3 (7.18â7.31), HCO3â 14.8 (12.8â18.6) mmol/L, and paCO2 3.4 (3.3â4.5) kPa). Three (43%) acidotic pregnant women fulfilled diagnostic criteria for RTA. All women recovered spontaneously within less 7 days. Conclusions: Metabolic acidosis seems to be very common (85%) in pregnant critically ill COVID-19 patients, and the prevalence of RTA might be higher than normal. It remains to be demonstrated if this observation is an indirect epiphenomenon or due to a direct viral effect on the tubular epithelium
Global invasion history of the emerging plant pathogen Phytophthora multivora
BACKGROUND: global trade in living plants and plant material has significantly increased the geographic distribution of many plant pathogens. As a consequence, several pathogens have been first found and described in their introduced range where they may cause severe damage on naĂŻve host species. Knowing the center of origin and the pathways of spread of a pathogen is of importance for several reasons, including identifying natural enemies and reducing further spread. Several Phytophthora species are well-known invasive pathogens of natural ecosystems, including Phytophthora multivora. Following the description of P. multivora from dying native vegetation in Australia in 2009, the species was subsequently found to be common in South Africa where it does not cause any remarkable disease. There are now reports of P. multivora from many other countries worldwide, but not as a commonly encountered species in natural environments. RESULTS: a global collection of 335 isolates from North America, Europe, Africa, Australia, the Canary Islands, and New Zealand was used to unravel the worldwide invasion history of P. multivora, using 10 microsatellite markers for all isolates and sequence data from five loci from 94 representative isolates. Our population genetic analysis revealed an extremely low heterozygosity, significant non-random association of loci and substantial genotypic diversity suggesting the spread of P. multivora readily by both asexual and sexual propagules. The P. multivora populations in South Africa, Australia, and New Zealand show the most complex genetic structure, are well established and evolutionary older than those in Europe, North America and the Canary Islands. CONCLUSION: according to the conducted analyses, the world invasion of P. multivora most likely commenced from South Africa, which can be considered the center of origin of the species. The pathogen was then introduced to Australia, which acted as bridgehead population for Europe and North America. Our study highlights a complex global invasion pattern of P. multivora, including both direct introductions from the native population and secondary spread/introductions from bridgehead populations.http://www.biomedcentral.com/bmcgenomicsForestry and Agricultural Biotechnology Institute (FABI
X-ray and radio bursts from the magnetar 1E 1547.0-5408
We report on simultaneous radio and X-ray observations of the radio-emitting magnetar 1E 1547.0-5408 on 2009 January 25 and February 3, with the 64 m Parkes radio telescope and the Chandra and XMM-Newton X-ray observatories. The magnetar was observed in a period of intense X-ray bursting activity and enhanced X-ray emission. We report here on the detection of two radio bursts from 1E 1547.0-5408 reminiscent of fast radio bursts (FRBs). One of the radio bursts was anticipated by âŒ1 s (about half a rotation period of the pulsar) by a bright SGR-like X-ray burst, resulting in a F/F ⌠10. Radio pulsations were not detected during the observation showing the FRB-like radio bursts, while they were detected in the previous radio observation. We also found that the two radio bursts are neither aligned with the latter radio pulsations nor with the peak of the X-ray pulse profile (phase shift of âŒ0.2). Comparing the luminosity of these FRB-like bursts and those reported from SGR 1935 +2154, we find that the wide range in radio efficiency and/or luminosity of magnetar bursts in the Galaxy may bridge the gap between âordinaryâ pulsar radio bursts and the extragalactic FRB phenomenon.G.L.I. and L.S. acknowledge funding from ASI-INAF agreements I/037/12/0 and 2017-14-H.O. G.L.I. and A.T. acknowledge financial support from the Italian MIUR PRIN
grant 2017LJ39LM. M.B., A.P., and L.S. acknowledge funding from the grant âiPeskaâ (INAF PRIN-SKA/CTA; PI Possenti). N.R. is supported by the ERC Consolidator Grant âMAGNESIAâ (nr.817661), and by grants SGR2017-1383 and PGC2018-095512-BI00. We acknowledge the support of the PHAROS COST Action (CA16214)
Leaf Area Estimation Model for Small Fruits from Linear Measurements
Accurate and nondestructive methods to determine individual leaf areas of plants are a useful tool in physiological and agronomic research. Determining the individual leaf area (LA) of small fruit like raspberry (Rubus idaeus L.), redcurrant (Ribes rubrum L.), blackberry (Rubus fruticosus L.), gooseberry (Ribes grossularia L.), and highbush blueberry (Vaccinium corymbosum L.) involves measurements of leaf parameters such as length (L) and width (W) or some combinations of these parameters. A 2-year investigation was carried out during 2006 (on seven raspberry, seven redcurrant, six blackberry, five gooseberry, and two highbush blueberry cultivars) and 2007 (on one cultivar per species) under open field conditions to test whether a model could be developed to estimate LA of small fruits across cultivars. Regression analysis of LA versus L and W revealed several models that could be used for estimating the area of individual small fruit leaves. A linear model having LW as the independent variable provided the most accurate estimate (highest R
2, smallest mean square error, and the smallest predicted residual error sum of squares) of LA in all small fruit berries. Validation of the model having LW of leaves measured in the 2007 experiment coming from other cultivars of small fruit berries showed that the correlation between calculated and measured small fruit berries LAs was very high. Therefore, these models can estimate accurately and in large quantities the LA of small fruit plants in many experimental comparisons without the use of any expensive instruments
Structural basis for chain release from the enacyloxin polyketide synthase
Modular polyketide synthases and nonribosomal peptide synthetases are molecular assembly lines consisting of several multienzyme subunits that undergo dynamic self-assembly to form a functional mega-complex. N- and C-terminal docking domains are usually responsible for mediating interactions between subunits. Here we show that communication between two nonribosomal peptide synthetase subunits responsible for chain release from the enacyloxin polyketide synthase, which assembles an antibiotic with promising activity against Acinetobacter baumannii, is mediated by an intrinsically disordered short linear motif and a Ă-hairpin docking domain. The structures, interactions and dynamics of these subunits are characterised using several complementary biophysical techniques, providing extensive insights into binding and catalysis. Bioinformatics analyses reveal that short linear motif/Ă-hairpin docking domain pairs mediate subunit interactions in numerous nonribosomal peptide and hybrid polyketide-nonribosomal peptide synthetases, including those responsible for assembling several important drugs. Short linear motifs and Ă-hairpin docking domains from heterologous systems are shown to interact productively, highlighting the potential of such interfaces as tools for biosynthetic engineering
High-dose recombinant interleukin-2/verapamil combination in advanced cancer.
No abstract availabl
p38-Îłâdependent gene silencing restricts entry into the myogenic differentiation program
The regenerative capacity of muscle is regulated by p38-Îł, which phosphorylates MyoD and leads to formation of a complex that represses myogenin transcription
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