652 research outputs found
Earthquake Hazard Analysis for Commercial Buildings in Memphis
https://deepblue.lib.umich.edu/bitstream/2027.42/154133/1/39015094008086.pd
Letâs talk about placental sex, baby: Understanding mechanisms that drive female-and male-specific fetal growth and developmental outcomes
It is well understood that sex differences exist between females and males even before they are born. These sex-dependent differences may contribute to altered growth and developmental outcomes for the fetus. Based on our initial observations in the human placenta, we hypothesised that the male prioritises growth pathways in order to maximise growth through to adulthood, thereby ensuring the greatest chance of reproductive success. However, this male-specific âevolutionary advantageâ likely contributes to males being less adaptable to shifts in the in-utero environment, which then places them at a greater risk for intrauterine morbidities or mortality. Comparatively, females are more adaptable to changes in the in-utero environment at the cost of growth, which may reduce their risk of poor perinatal outcomes. The mechanisms that drive these sex-specific adaptations to a change in the in-utero environment remain unclear, but an increasing body of evidence within the field of developmental biology would suggest that alterations to placental function, as well as the feto-placental hormonal milieu, is an important contributing factor. Herein, we have addressed the current knowledge regarding sex-specific intrauterine growth differences and have examined how certain pregnancy complications may alter these female- and male-specific adaptations.Ashley S. Meakin, James S. M. Cuffe, Jack R. T. Darby, Janna L. Morrison and Vicki L. Clifto
Spectroscopic observations of the ÎŽ Scorpii binary during its recent periastron passage
The bright star Ύ Sco has been considered a typical B0-type object for many years. Spectra of the star published prior to 1990 showed no evidence of emission, but only of short-term line profile variations attributed to nonradial pulsations. Speckle interferometric observations show that Ύ Sco is a binary system with a highlyeccentric orbit and a period of ~10.6 years. Weak emission in the Hα line was detected in its spectrum for the rst time during a periastron passage in 1990. Shortly before the next periastron passage in the summer of 2000, the binary entered a strong Hα emission and enhanced mass-loss phase. We monitored the spectroscopic development of the Be outburst from July 2000 through March 2001. In this paper we present results from our spectroscopy, refine elements of the binary orbit, and discuss possible mechanisms for the mass loss.Fabregat Llueca, Juan, [email protected] ;
Blay Serrano, Pedro Jose, [email protected]
Indirect Impact of PD-1/PD-L1 Blockade on a Murine Model of NK Cell Exhaustion
The induction of exhaustion on effector immune cells is an important limiting factor
for cancer immunotherapy efficacy as these cells undergo a hierarchical loss of
proliferation and cytolytic activity due to chronic stimulation. Targeting PD-1 has shown
unprecedented clinical benefits for many cancers, which have been attributed to the
prevention of immune suppression and exhaustion with enhanced anti-tumor responses.
In this study, we sought to evaluate the role of the PD-1/PD-L1 pathway in murine
natural killer (NK) cell activation, function, and exhaustion. In an in vivo IL-2-dependent
exhaustion mouse model, neutralization of the PD-1/PD-L1 pathway improved NK
cell activation after chronic stimulation when compared to control-treated mice. These
cells displayed higher proliferative capabilities and enhanced granzyme B production.
However, the blockade of these molecules during long-term in vitro IL-2 stimulation did
not alter the progression of NK cell exhaustion (NCE), suggesting an indirect involvement
of PD-1/PD-L1 on NCE. Given the expansion of CD8 T cells and regulatory T cells (Tregs)
observed upon acute and chronic stimulation with IL-2, either of these two populations
could influence NK cell homeostasis after PD-L1/PD-1 therapy. Importantly, CD8 T cell
activation and functional phenotype were indeed enhanced by PD-1/PD-L1 therapy,
particularly with anti-PD-1 treatment that resulted in the highest upregulation of CD25
during chronic stimulation and granted an advantage for IL-2 over NK cells. These
results indicate a competition for resources between NK and CD8 T cells that arguably
delays the onset of NCE rather than improving its activation during chronic stimulation.
Supporting this notion, the depletion of CD8 T cells reversed the benefits of PD-1 therapy
on chronically stimulated NK cells. These data suggest a bystander effect of anti-PD1
on NK cells, resulting from the global competition that exists between NK and CD8 T
cells for IL-2 as a key regulator of these cellsâ activation. Thus, achieving an equilibrium
between these immune cells might be important to accomplish long-term efficacy during
anti-PD-1/IL-2 therapy
Obstructions to the Existence of Sasaki-Einstein Metrics
We describe two simple obstructions to the existence of Ricci-flat Kahler
cone metrics on isolated Gorenstein singularities or, equivalently, to the
existence of Sasaki-Einstein metrics on the links of these singularities. In
particular, this also leads to new obstructions for Kahler-Einstein metrics on
Fano orbifolds. We present several families of hypersurface singularities that
are obstructed, including 3-fold and 4-fold singularities of ADE type that have
been studied previously in the physics literature. We show that the AdS/CFT
dual of one obstruction is that the R-charge of a gauge invariant chiral
primary operator violates the unitarity bound.Comment: 35 pages, 1 figure; references and a footnote adde
Numerical Portrait of a Relativistic Thin Film BCS Superfluid
We present results of numerical simulations of the 2+1d Nambu - Jona-Lasinio
model with a non-zero baryon chemical potential mu including the effects of a
diquark source term. Diquark condensates, susceptibilities and masses are
measured as functions of source strength j. The results suggest that diquark
condensation does not take place in the high density phase mu>mu_c, but rather
that the condensate scales non-analytically with j implying a line of critical
points and long range phase coherence. Analogies are drawn with the low
temperature phase of the 2d XY model. The spectrum of the spin-1/2 sector is
also studied yielding the quasiparticle dispersion relation. There is no
evidence for a non-zero gap; rather the results are characteristic of a normal
Fermi liquid with Fermi velocity less than that of light. We conclude that the
high density phase of the model describes a relativistic gapless thin film BCS
superfluid.Comment: 37 pages, 16 figure
Semaphorin 3F signaling actively retains neutrophils at sites of inflammation
Neutrophilic inflammation is central to disease pathogenesis, for example, in chronic obstructive pulmonary disease, yet the mechanisms that retain neutrophils within tissues remain poorly understood. With emerging evidence that axon guidance factors can regulate myeloid recruitment and that neutrophils can regulate expression of a class 3 semaphorin, SEMA3F, we investigated the role of SEMA3F in inflammatory cell retention within inflamed tissues. We observed that neutrophils upregulate SEMA3F in response to proinflammatory mediators and following neutrophil recruitment to the inflamed lung. In both zebrafish tail injury and murine acute lung injury models of neutrophilic inflammation, overexpression of SEMA3F delayed inflammation resolution with slower neutrophil migratory speeds and retention of neutrophils within the tissues. Conversely, constitutive loss of sema3f accelerated egress of neutrophils from the tail injury site in fish, whereas neutrophil-specific deletion of Sema3f in mice resulted in more rapid neutrophil transit through the airways, and significantly reduced time to resolution of the neutrophilic response. Study of filamentous-actin (F-actin) subsequently showed that SEMA3F-mediated retention is associated with F-actin disassembly. In conclusion, SEMA3F signaling actively regulates neutrophil retention within the injured tissues with consequences for neutrophil clearance and inflammation resolution
Differential cross section and recoil polarization measurements for the gamma p to K+ Lambda reaction using CLAS at Jefferson Lab
We present measurements of the differential cross section and Lambda recoil
polarization for the gamma p to K+ Lambda reaction made using the CLAS detector
at Jefferson Lab. These measurements cover the center-of-mass energy range from
1.62 to 2.84 GeV and a wide range of center-of-mass K+ production angles.
Independent analyses were performed using the K+ p pi- and K+ p (missing pi -)
final-state topologies; results from these analyses were found to exhibit good
agreement. These differential cross section measurements show excellent
agreement with previous CLAS and LEPS results and offer increased precision and
a 300 MeV increase in energy coverage. The recoil polarization data agree well
with previous results and offer a large increase in precision and a 500 MeV
extension in energy range. The increased center-of-mass energy range that these
data represent will allow for independent study of non-resonant K+ Lambda
photoproduction mechanisms at all production angles.Comment: 22 pages, 16 figure
Tensor Correlations Measured in 3He(e,e'pp)n
We have measured the 3He(e,e'pp)n reaction at an incident energy of 4.7 GeV
over a wide kinematic range. We identified spectator correlated pp and pn
nucleon pairs using kinematic cuts and measured their relative and total
momentum distributions. This is the first measurement of the ratio of pp to pn
pairs as a function of pair total momentum, . For pair relative
momenta between 0.3 and 0.5 GeV/c, the ratio is very small at low and
rises to approximately 0.5 at large . This shows the dominance of
tensor over central correlations at this relative momentum.Comment: 4 pages, 4 figures, submitted to PR
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