1,346 research outputs found
Far-Ultraviolet and Far-Infrared Bivariate Luminosity Function of Galaxies: Complex Relation between Stellar and Dust Emission
Far-ultraviolet (FUV) and far-infrared (FIR) luminosity functions (LFs) of
galaxies show a strong evolution from to , but the FIR LF
evolves much stronger than the FUV one. The FUV is dominantly radiated from
newly formed short-lived OB stars, while the FIR is emitted by dust grains
heated by the FUV radiation field. It is known that dust is always associated
with star formation activity. Thus, both FUV and FIR are tightly related to the
star formation in galaxies, but in a very complicated manner. In order to
disentangle the relation between FUV and FIR emissions, we estimate the UV-IR
bivariate LF (BLF) of galaxies with {\sl GALEX} and {\sl AKARI} All-Sky Survey
datasets. Recently we invented a new mathematical method to construct the BLF
with given marginals and prescribed correlation coefficient. This method makes
use of a tool from mathematical statistics, so called "copula". The copula
enables us to construct a bivariate distribution function from given marginal
distributions with prescribed correlation and/or dependence structure. With
this new formulation and FUV and FIR univariate LFs, we analyze various FUV and
FIR data with {\sl GALEX}, {\sl Spitzer}, and {\sl AKARI} to estimate the UV-IR
BLF. The obtained BLFs naturally explain the nonlinear complicated relation
between FUV and FIR emission from star-forming galaxies. Though the faint-end
of the BLF was not well constrained for high- samples, the estimated linear
correlation coefficient was found to be very high, and is remarkably
stable with redshifts (from 0.95 at to 0.85 at ). This implies
the evolution of the UV-IR BLF is mainly due to the different evolution of the
univariate LFs, and may not be controlled by the dependence structure.Comment: 10 pages, 7 figures, Earth, Planets and Space, in pres
Overcharging of a macroion by an oppositely charged polyelectrolyte
The complexation of a polyelectrolyte with an oppositely charged spherical
macroion is studied for both salt free and salty solutions. When a
polyelectrolyte winds around the macroion, its turns repel each other and form
an almost equidistant coil. It is shown that this repulsive correlations of
turns lead to the charge inversion: more polyelectrolyte winds around the
macroion than it is necessary to neutralize it. The charge inversion becomes
stronger with increasing concentration of salt and can exceed 100%. This paper
confirms that correlations are the universal mechanism of charge inversion.Comment: Monte-Carlo simulation details added. Many corrections and references
added. Accepted to Physica
On-site detection of equid alphaherpesvirus 3 in perineal and genital swabs of mares and stallions
Equine coital exanthema (ECE) is an infectious, venereally transmitted muco-cutaneous disease affecting mares and stallions, caused by equid alphaherpesvirus 3 (EHV3). Diagnostic tools for rapid identification of EHV3 are of primary importance to diminish the risk of EHV3 dissemination at the time of breeding. In the last years, it has been shown that the performance of the insulated-isothermal polymerase chain reaction (iiPCR) is comparable to virus isolation, nested PCR and real-time PCR (qPCR) in detecting pathogens of various animal species. Analytical sensitivity and specificity of the iiPCR were compared with a qPCR, using a plasmid containing the target region of the EHV3 glycoprotein G gene and an Argentinian EHV3 isolate (E/9283/07 C3A). In order to evaluate the diagnostic performance of the iiPCR, nucleic acids of 85 perineal and genital swabs (PGS) of mares and stallions were extracted by tacoTM mini and tested by both techniques. EHV3 was detected in 46 and 45 of the 85 PGS by the iiPCR and qPCR, respectively. There was almost perfect agreement between the two diagnostic methods (98.82%; 95% CI: 95.03–100%; κ = 0.98). The iiPCR had a limit of detection of 95.00% at 6 genome equivalents per reaction and a detection endpoint for viral DNA comparable to that of the qPCR, and did not react with six non-targeted equine pathogens. The iiPCR represents a sensitive and specific method for the rapid on-site diagnosis of EHV3 infection. Its routinely implementation in breeding facilities, and artificial insemination and embryo transfer centers, will contribute to prevent the dissemination of this venereal, highly contagious disease in horses.Fil: Vissani, María Aldana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Tordoya, Maria Silvia. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Tsai, Y.-L.. GeneReach; Estados UnidosFil: Lee, P.-Y.A.. GeneReach; Estados UnidosFil: Shen, Y.-H.. GeneReach; Estados UnidosFil: Lee, F.-C.. GeneReach; Estados UnidosFil: Wang, H.-T.T.. GeneReach; Estados UnidosFil: Parreño, Gladys Viviana. Instituto Nacional de Tecnología Agropecuaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Barrandeguy, María Edith. Instituto Nacional de Tecnología Agropecuaria; Argentina. Universidad del Salvador. Escuela de Veterinaria; Argentin
Study on the Activity of PI3K/AKT, Death Receptor and 14-3-3 Mediated Signaling Pathways Regulating Hepatocyte Apoptosis during Rat Liver Regeneration
Studies have shown that apoptosis is closely related to the rat liver regeneration. To understand the mechanism of hepatocyte apoptosis during rat liver regeneration at the gene transcription level, the Rat Genome 230 2.0 Array was used to determine the expression changes of genes. Then the genes associated with cell apoptosis were searched by GO and NCBI databases, and cell apoptosis signaling pathways were searched by the database of QIAGEN and KEGG. Their signaling activities were calculated by spectral function E(t). The mechanism of hepatocyte apoptosis during rat liver regeneration was analyzed by Ingenuity Pathway Analysis 9.0 (IPA). The results showed that among the 27 signaling pathways regulating cell apoptosis, the E(t) values of Apoptosis signaling pathway and 14-3-3 mediated signaling pathway were significantly increased in the progression phase (6-72h after PH) of rat liver regeneration, and the E(t) values of hepatocyte apoptosis mediated by mitochondria rout were also significantly increased. The E(t) values of death receptor signaling pathway and PI3K/AKT branch of 14-3-3 mediated signaling pathway were significantly increased in the progression phase and the terminal phase (72-168h after PH) of rat liver regeneration, and the E(t) values of hepatocyte apoptosis mediated by cytomembrane route and nucleus route were also significantly increased. Conclusion: PI3K/AKT, death receptor and mitochondria branch played a key role in promoting cell apoptosis during rat liver regeneration
Comparative Assessment of the Binding and Neutralisation Activity of Bispecific Antibodies Against SARS-CoV-2 Variants.
Neutralising antibodies against SARS-CoV-2 are a vital component in the fight against COVID-19 pandemic, having the potential of both therapeutic and prophylactic applications. Bispecific antibodies (BsAbs) against SARS-CoV-2 are particularly promising, given their ability to bind simultaneously to two distinct sites of the receptor-binding domain (RBD) of the viral spike protein. Such antibodies are complex molecules associated with multi-faceted mechanisms of action that require appropriate bioassays to ensure product quality and manufacturing consistency.
We developed procedures for biolayer interferometry (BLI) and a cell-based virus neutralisation assay, the focus reduction neutralisation test (FRNT). Using both assays, we tested a panel of five BsAbs against different spike variants (Ancestral, Delta and Omicron) to evaluate the use of these analytical methods in assessing binding and neutralisation activities of anti-SARS-CoV-2 therapeutics.
We found comparable trends between BLI-derived binding affinity and FRNT-based virus neutralisation activity. Antibodies that displayed high binding affinity against a variant were often followed by potent neutralisation at lower concentrations, whereas those with low binding affinity also demonstrated reduced neutralisation activity.
The results support the utility of BLI and FRNT assays in measuring variant-specific binding and virus neutralisation activity of anti-SARS-CoV-2 antibodies
Modelling metal accumulation using humic acid as a surrogate for plant roots
Metal accumulation in roots was modelled with WHAM VII using humic acid (HA) as a surrogate for root surface. Metal accumulation was simulated as a function of computed metal binding to HA, with a correction term (EHA) to account for the differences in binding site density between HA and root surface. The approach was able to model metal accumulation in roots to within one order of magnitude for 95% of the data points. Total concentrations of Mn in roots of Vigna unguiculata, total concentrations of Ni, Zn, Cu and Cd in roots of Pisum sativum, as well as internalized concentrations of Cd, Ni, Pb and Zn in roots of Lolium perenne, were significantly correlated to the computed metal binding to HA. The method was less successful at modelling metal accumulation at low concentrations and in soil experiments. Measured concentrations of Cu internalized in L. perenne roots were not related to Cu binding to HA modelled and deviated from the predictions by over one order of magnitude. The results indicate that metal uptake by roots may under certain conditions be influenced by conditional physiological processes that cannot simulated by geochemical equilibrium. Processes occurring in chronic exposure of plants grown in soil to metals at low concentrations complicate the relationship between computed metal binding to HA and measured metal accumulation in roots
Multiwavelength Study of M8.9/3B Solar Flare from AR NOAA 10960
We present a multi-wavelength analysis of a long duration white-light solar
flare (M8.9/3B) event that occurred on 4 June 2007 from NOAA AR 10960. The
flare was observed by several spaceborne instruments, namely SOHO/MDI,
Hinode/SOT, TRACE and STEREO/SECCHI. The flare was initiated near a small,
positive-polarity, satellite sunspot at the centre of the AR, surrounded by
opposite-polarity field regions. MDI images of the AR show considerable amount
of changes in a small positive-polarity sunspot of delta configuration during
the flare event. SOT/G-band (4305 A) images of the sunspot also suggest the
rapid evolution of the positive-polarity sunspot with highly twisted penumbral
filaments before the flare event, which were oriented in the counterclockwise
direction. It shows the change in orientation and also remarkable disappearance
of twisted penumbral filaments (~35-40%) and enhancement in umbral area
(~45-50%) during the decay phase of the flare. TRACE and SECCHI observations
reveal the successive activations of two helical twisted structures associated
with this sunspot, and the corresponding brightening in the chromosphere as
observed by the time-sequence images of SOT/Ca II H line (3968 A). The
secondary-helical twisted structure is found to be associated with the M8.9
flare event. The brightening starts 6-7 min prior to the flare maximum with the
appearance of secondary helical-twisted structure. The flare intensity
maximizes as this structure moves away from the AR. This twisted flux-tube
associated with the flare triggering, is found to be failed in eruption. The
location of the flare is found to coincide with the activation site of the
helical twisted structures. We conclude that the activations of successive
helical twists in the magnetic flux tubes/ropes plays a crucial role in the
energy build-up process and triggering of M-class solar flare without a CME.Comment: 22 pages, 12 figures, Accepted for Publication in Solar Physic
Severe disruption and disorganization of dermal collagen fibrils in early striae gravidarum
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142909/1/bjd15895.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142909/2/bjd15895_am.pd
Assessment of the Biocompatibility of the PLLA-PLCL Scaffold Obtained by Electrospinning
AbstractElectrospun membranes of poly (L-Lactide) / poly (L-lactide-co-caprolactone) blend were produced and evaluated by physical and mechanical tests to use as a scaffold for cell growth. The membranes were seeded with endothelial cells (HUVEC) and after culturing time it was visualized by confocal laser scanning microscopy and scanning electron microscopy. The results indicate that the process parameters were capable of producing PLLA-PLCL membranes presenting fibers with diameters in the nanometer range. The scaffolds supported cell attachment and growth, indicating the feasibility of producing scaffolds by electrospinning technique, which could be used in tissue engineering applications
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