209 research outputs found
In Vitro and In Vivo Evidence that Thrombospondin-1 (TSP-1) Contributes to Stirring- and Shear-Dependent Activation of Platelet-Derived TGF-β1
Thrombospondin 1 (TSP-1), which is contained in platelet α-granules and released with activation, has been shown to activate latent TGF-β1 in vitro, but its in vivo role is unclear as TSP-1-null (Thbs1−/−) mice have a much less severe phenotype than TGF-β1-null (Tgfb1−/−) mice. We recently demonstrated that stirring and/or shear could activate latent TGF-β1 released from platelets and have now studied these methods of TGF-β1 activation in samples from Thbs1−/− mice, which have higher platelet counts and higher levels of total TGF-β1 in their serum than wild type mice. After either two hours of stirring or shear, Thbs1−/− samples demonstrated less TGF-β1 activation (31% and 54% lower levels of active TGF-β1 in serum and platelet releasates, respectively). TGF-β1 activation in Thbs1−/− mice samples was normalized by adding recombinant human TSP-1 (rhTSP-1). Exposure of platelet releasates to shear for one hour led to near depletion of TSP-1, but this could be prevented by preincubating samples with thiol-reactive agents. Moreover, replenishing rhTSP-1 to human platelet releasates after one hour of stirring enhanced TGF-β1 activation. In vivo TGF-β1 activation in carotid artery thrombi was also partially impaired in Thbs1−/− mice. These data indicate that TSP-1 contributes to shear-dependent TGF-β1 activation, thus providing a potential explanation for the inconsistent in vitro data previously reported as well as for the differences in phenotypes of Thbs1−/− and Tgfb1−/− mice
Cathecol and Naphtol groups in Salphen-Type Schiff Bases for the preparation of polynuclear complexes
In this paper, we show a strategy to modify salphen-type Schiff base ligands with naphtol (SYML1) and pyrocathecol (2,3-dihydroxyphenyl) groups (SYML2), or a combination of both (ASYML). Each of these ligands can be used to obtain polynuclear metal complexes following two different strategies. One relies on using metals that are either too large for the N2O2 cavity or not fond of coordination number 4 and the other one relies on forcing the polynuclear species by adding functional groups to the hydroxybenzaldehayde in order to have extra coordination sites in the ligand. We report and characterize the mononuclear complexes SYML1-Cu and SYML1-Ce, along with the dinuclear complex SYML1-Fe and the tetranuclear species SYML2-Mn. The asymmetric ligand ASYML routinely hydrolyzes into the symmetric ligands in the reaction mixtures. SYML1-Fe displays a nearly linear Fe-O-Fe bridge with very strong antiferromagnetic coupling between the Fe(III) ions
The use of social network analysis to describe the effect of immune activation on group dynamics in pigs
The immune system can influence social motivation with potentially dire consequences for group-housed production animals, such as pigs. The aim of this study was to test the effect of a controlled immune activation in group-housed pigs, through an injection with lipopolysaccharide (LPS) and an intervention with ketoprofen on centrality parameters at the individual level. In addition, we wanted to test the effect of time relative to the injection on general network parameters in order to get a better understanding of changes in social network structures at the group level. 52 female pigs (11-12 weeks) were allocated to four treatments, comprising two injections: ketoprofen-LPS (KL), ketoprofen-saline (KS), saline-LPS (SL) and saline-saline (SS). Social behaviour with a focus on damaging behaviour was observed continuously in 10 x 15 min bouts between 0800 am and 1700 pm 1 day before (baseline) and two subsequent days after injection. Activity was scan-sampled every 5 min for 6 h after the last injection in the pen. Saliva samples were taken for cortisol analysis at baseline and at 4, 24, 48, 72 h after the injections. A controlled immune activation affected centrality parameters for ear manipulation networks at the individual level. Lipopolysaccharide-injected pigs had a lower in-degree centrality, thus, received less interactions, 2 days after the challenge. Treatment effects on tail manipulation and fighting networks were not observed at the individual level. For networks of manipulation of other body parts, in-degree centrality was positively correlated with cortisol response at 4 h and lying behaviour in the first 6 h after the challenge in LPS-injected pigs. Thus, the stronger the pigs reacted to the LPS, the more interactions they received in the subsequent days. The time in relation to injection affected general network parameters for ear manipulation and fighting networks at the group level. For ear manipulation networks, in -degree centralisation was higher on the days following injection, thus, certain individuals in the pen received more interactions than the rest of the group compared to baseline. For fighting networks, betweenness decreased on the first day after injection compared to baseline, indicating that network connectivity increased after the challenge. Networks of tail manipulation and manipulation of other body parts did not change on the days after injection at the group level. Social network analysis is a method that can potentially provide important insights into the effects of sickness on social behaviour in group-housed pigs. (c) 2021 The Authors. Published by Elsevier B.V. on behalf of The Animal Consortium. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe
Interfacial intermetallic growth and strength of composite lead-free solder alloy through isothermal aging
The effects of particle reinforcement of Sn-4.0wt.%Ag-0.5wt.%Cu (SAC405) lead-free solder on interfacial intermetallic layer growth and strength of the ensuing joints through short-term isothermal aging (150 degrees C) were studied. Composite solders were prepared by either incorporating 2 wt.% Cu (3 mu m to 20 mu m) or Cu2O (similar to 150 nm) particles into SAC405 paste. Aggressive flux had the effect of reducing the Cu2O nanoparticles into metallic Cu which subsequently reacted with the solder alloy to form the Cu6Sn5 intermetallic. While all solders had similar interfacial intermetallic growth upon reflow, both of the composite solders' growth rates slowed through aging to reach a common growth rate exponent of approximately 0.38, considerably lower than that of the nonreinforced solder (n = 0.58). The nanoscale reinforced solder additionally exhibited the highest tensile strength in both the initial and aged conditions, behavior also attributed to its quick conversion to a stable microstructure
A frozen super-Earth orbiting a star at the bottom of the Main Sequence
We observed the microlensing event MOA-2007-BLG-192 at high angular
resolution in JHKs with the NACO adaptive optics system on the VLT while the
object was still amplified by a factor 1.23 and then at baseline 18 months
later. We analyzed and calibrated the NACO photometry in the standard 2MASS
system in order to accurately constrain the source and the lens star fluxes. We
detect light from the host star of MOA-2007-BLG-192Lb, which significantly
reduces the uncertainties in its char- acteristics as compared to earlier
analyses. We find that MOA-2007-BLG-192L is most likely a very low mass late
type M-dwarf (0.084 [+0.015] [-0.012] M\odot) at a distance of 660 [+100] [-70]
pc orbited by a 3.2 [+5.2] [-1.8] M\oplus super-Earth at 0.66 [+0.51] [-0.22]
AU. We then discuss the properties of this cold planetary system.Comment: published version A&A 540, A78 (2012) A&A, 10 pages, 7 Figure
MOA-2009-BLG-387Lb: A massive planet orbiting an M dwarf
We report the discovery of a planet with a high planet-to-star mass ratio in
the microlensing event MOA-2009-BLG-387, which exhibited pronounced deviations
over a 12-day interval, one of the longest for any planetary event. The host is
an M dwarf, with a mass in the range 0.07 M_sun < M_host < 0.49M_sun at 90%
confidence. The planet-star mass ratio q = 0.0132 +- 0.003 has been measured
extremely well, so at the best-estimated host mass, the planet mass is m_p =
2.6 Jupiter masses for the median host mass, M = 0.19 M_sun. The host mass is
determined from two "higher order" microlensing parameters. One of these, the
angular Einstein radius \theta_E = 0.31 +- 0.03 mas, is very well measured, but
the other (the microlens parallax \pi_E, which is due to the Earth's orbital
motion) is highly degenate with the orbital motion of the planet. We
statistically resolve the degeneracy between Earth and planet orbital effects
by imposing priors from a Galactic model that specifies the positions and
velocities of lenses and sources and a Kepler model of orbits. The 90%
confidence intervals for the distance, semi-major axis, and period of the
planet are 3.5 kpc < D_L < 7.9 kpc, 1.1 AU < a < 2.7AU, and 3.8 yr < P < 7.6
yr, respectively.Comment: 20 pages including 8 figures. A&A 529 102 (2011
Frequency of Solar-Like Systems and of Ice and Gas Giants Beyond the Snow Line from High-Magnification Microlensing Events in 2005-2008
We present the first measurement of planet frequency beyond the "snow line"
for planet/star mass-ratios[-4.5<log q<-2]: d^2 N/dlog q/dlog
s=(0.36+-0.15)/dex^2 at mean mass ratio q=5e-4, and consistent with being flat
in log projected separation, s. Our result is based on a sample of 6 planets
detected from intensive follow-up of high-mag (A>200) microlensing events
during 2005-8. The sample host stars have typical mass M_host 0.5 Msun, and
detection is sensitive to planets over a range of projected separations
(R_E/s_max,R_E*s_max), where R_E 3.5 AU sqrt(M_host/Msun) is the Einstein
radius and s_max (q/5e-5)^{2/3}, corresponding to deprojected separations ~3
times the "snow line". Though frenetic, the observations constitute a
"controlled experiment", which permits measurement of absolute planet
frequency. High-mag events are rare, but the high-mag channel is efficient:
half of high-mag events were successfully monitored and half of these yielded
planet detections. The planet frequency derived from microlensing is a factor 7
larger than from RV studies at factor ~25 smaller separations [2<P<2000 days].
However, this difference is basically consistent with the gradient derived from
RV studies (when extrapolated well beyond the separations from which it is
measured). This suggests a universal separation distribution across 2 dex in
semi-major axis, 2 dex in mass ratio, and 0.3 dex in host mass. Finally, if all
planetary systems were "analogs" of the Solar System, our sample would have
yielded 18.2 planets (11.4 "Jupiters", 6.4 "Saturns", 0.3 "Uranuses", 0.2
"Neptunes") including 6.1 systems with 2 or more planet detections. This
compares to 6 planets including one 2-planet system in the actual sample,
implying a first estimate of 1/6 for the frequency of solar-like systems.Comment: 42 pages, 10 figure
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