769 research outputs found
A systematic review of the neutrophil to lymphocyte and platelet to lymphocyte ratios in patients with lower extremity arterial disease
Summary: Background: Lower extremity arterial disease (LEAD) is caused by atherosclerotic plaque in the arterial supply to the lower limbs. The neutrophil to lymphocyte and platelet to lymphocyte ratios (NLR, PLR) are established markers of systemic inflammation which are related to inferior outcomes in multiple clinical conditions, though remain poorly described in patients with LEAD. Material and methods: This review was carried out in accordance with PRISMA guidelines. The MEDLINE database was interrogated for relevant studies. Primary outcome was the prognostic effect of NLR and PLR on clinical outcomes following treatment, and secondary outcomes were the prognostic effect of NLR and PLR on disease severity and technical success following revascularisation. Results: There were 34 studies included in the final review reporting outcomes on a total of 19870 patients. NLR was investigated in 21 studies, PLR was investigated in two studies, and both NLR & PLR were investigated in 11 studies. Relating to increased levels of systemic inflammation, 20 studies (100%) reported inferior clinical outcomes, 13 (92.9%) studies reported increased disease severity, and seven (87.5%) studies reported inferior technical results from revascularisation. Conclusions: The studies included in this review support the role of elevated NLR and PLR as key components influencing the clinical outcomes, severity, and success of treatment in patients with LEAD. The use of these easily accessible, cost effective and routinely available markers is supported by the present review
Linear Contraction Behavior of Low-Carbon, Low-Alloy Steels During and After Solidification Using Real-Time Measurements
A technique for measuring the linear contraction during and after solidification of low-alloy steel was developed and used for examination of two commercial low-carbon and low-alloy steel grades. The effects of several experimental parameters on the contraction were studied. The solidification contraction behavior was described using the concept of rigidity in a solidifying alloy, evolution of the solid fraction, and the microstructure development during solidification. A correlation between the linear contraction properties in the solidification range and the hot crack susceptibility was proposed and used for the estimation of hot cracking susceptibility for two studied alloys and verified with the real casting practice. The technique allows estimation of the contraction coefficient of commercial steels in a wide range of temperatures and could be helpful for computer simulation and process optimization during continuous casting. © 2013 The Minerals, Metals & Materials Society and ASM International
T-bet controls intestinal mucosa immune responses via repression of type 2 innate lymphoid cell function
Innate lymphoid cells (ILCs) play an important role in regulating immune responses at mucosal surfaces. The transcription factor T-bet is crucial for the function of ILC1s and NCR+ ILC3s and constitutive deletion of T-bet prevents the development of these subsets. Lack of T-bet in the absence of an adaptive immune system causes microbiota-dependent colitis to occur due to aberrant ILC3 responses. Thus, T-bet expression in the innate immune system has been considered to dampen pathogenic immune responses. Here, we show that T-bet plays an unexpected role in negatively regulating innate type 2 responses, in the context of an otherwise intact immune system. Selective loss of T-bet in ILCs leads to the expansion and increased activity of ILC2s, which has a functionally important impact on mucosal immunity, including enhanced protection from Trichinella spiralis infection and inflammatory colitis. Mechanistically, we show that T-bet controls the intestinal ILC pool through regulation of IL-7 receptor signalling. These data demonstrate that T-bet expression in ILCs acts as the key transcriptional checkpoint in regulating pathogenic vs. protective mucosal immune responses, which has significant implications for the understanding of the pathogenesis of inflammatory bowel diseases and intestinal infections
Stochastic Vehicle Routing with Recourse
We study the classic Vehicle Routing Problem in the setting of stochastic
optimization with recourse. StochVRP is a two-stage optimization problem, where
demand is satisfied using two routes: fixed and recourse. The fixed route is
computed using only a demand distribution. Then after observing the demand
instantiations, a recourse route is computed -- but costs here become more
expensive by a factor lambda.
We present an O(log^2 n log(n lambda))-approximation algorithm for this
stochastic routing problem, under arbitrary distributions. The main idea in
this result is relating StochVRP to a special case of submodular orienteering,
called knapsack rank-function orienteering. We also give a better approximation
ratio for knapsack rank-function orienteering than what follows from prior
work. Finally, we provide a Unique Games Conjecture based omega(1) hardness of
approximation for StochVRP, even on star-like metrics on which our algorithm
achieves a logarithmic approximation.Comment: 20 Pages, 1 figure Revision corrects the statement and proof of
Theorem 1.
Time Variations in the Scale of Grand Unification
We study the consequences of time variations in the scale of grand
unification, , when the Planck scale and the value of the unified coupling
at the Planck scale are held fixed. We show that the relation between the
variations of the low energy gauge couplings is highly model dependent. It is
even possible, in principle, that the electromagnetic coupling varies,
but the strong coupling does not (to leading approximation). We
investigate whether the interpretation of recent observations of quasar
absorption lines in terms of time variation in can be accounted for by
time variation in . Our formalism can be applied to any scenario where a
time variation in an intermediate scale induces, through threshold corrections,
time variations in the effective low scale couplings.Comment: 14 pages, revtex4; Updated observational results and improved
statistical analysis (section IV); added reference
Primordial nucleosynthesis with a varying fine structure constant: An improved estimate
We compute primordial light-element abundances for cases with fine structure
constant alpha different from the present value, including many sources of
alpha dependence neglected in previous calculations. Specifically, we consider
contributions arising from Coulomb barrier penetration, photon coupling to
nuclear currents, and the electromagnetic components of nuclear masses. We find
the primordial abundances to depend more weakly on alpha than previously
estimated, by up to a factor of 2 in the case of ^7Li. We discuss the
constraints on variations in alpha from the individual abundance measurements
and the uncertainties affecting these constraints. While the present best
measurements of primordial D/H, ^4He/H, and ^7Li/H may be reconciled pairwise
by adjusting alpha and the universal baryon density, no value of alpha allows
all three to be accommodated simultaneously without consideration of systematic
error. The combination of measured abundances with observations of acoustic
peaks in the cosmic microwave background favors no change in alpha within the
uncertainties.Comment: Phys. Rev. D accepted version; minor changes in response to refere
Constraints on the Variation of the Fine Structure Constant from Big Bang Nucleosynthesis
We put bounds on the variation of the value of the fine structure constant
, at the time of Big Bang nucleosynthesis. We study carefully all light
elements up to Li. We correct a previous upper limit on estimated from He primordial abundance and we find interesting new
potential limits (depending on the value of the baryon-to-photon ratio) from
Li, whose production is governed to a large extent by Coulomb barriers. The
presently unclear observational situation concerning the primordial abundances
preclude a better limit than |\Delta \alpha/\alpha| \lsim 2\cdot 10^{-2}, two
orders of magnitude less restrictive than previous bounds. In fact, each of the
(mutually exclusive) scenarios of standard Big Bang nucleosynthesis proposed,
one based on a high value of the measured deuterium primordial abundance and
one based on a low value, may describe some aspects of data better if a change
in of this magnitude is assumed.Comment: 21 pages, eps figures embedded using epsfig macr
The relationship between Clinical Frailty Score, CT-derived body composition, systemic inflammation, and survival in patients with chronic limb-threatening ischemia
Background:
Frailty is a chronic condition with complex etiology and impaired functional performance that has been associated with altered body composition and chronic inflammation. Chronic limb-threatening ischemia (CLTI) carries significant morbidity and mortality and is associated with poor quality of life. The present study aims to examine these relationships and their prognostic value in patients with CLTI.
Methods:
Consecutive patients presenting as unscheduled admissions to a single tertiary center with CLTI were included over a 12-month period. Frailty was diagnosed using the Clinical Frailty Scale (CFS). Body composition was assessed using computerised tomography (CT) at the L3 vertebral level (CT-BC) to generate visceral and subcutaneous fat indices, skeletal muscle index, and skeletal muscle density. Skeletal muscle index and skeletal muscle density were combined to form the CT-sarcopenia score (CT-SS). Systemic inflammation was assessed by the modified Glasgow prognostic score (mGPS). The primary outcome was overall mortality.
Results:
There were 190 patients included with a median (interquartile range) follow-up of 22 (6) months (range 15â32 months) and 79 deaths during the follow-up period. One hundred patients (53%) had a CFS >4. CFS >4 (hazard ratio [HR] 2.14, 95% confidence interval [CI] 1.25â3.66, P < 0.01), CT-SS (HR 1.47, 95% CI 1.03â2.09, P < 0.05), and mGPS (HR 1.54, 95% CI 1.11â2.13, P < 0.01) were independently associated with increased mortality. CT-SS (odds ratio 1.88, 95% CI 1.09â3.24, P < 0.01) was independently associated with CFS >4. Patients with CT-SS 0 and CFS â€4 had 90% (standard error [SE] 5%) 1-year survival, compared with 35% (SE 9%) in patients with CT-SS 2 and CFS >4 (P < 0.001). Patients with mGPS 0 and CFS â€4 had 94% (SE 4%) 1-year survival compared with 44% (SE 6%) in the mGPS 2 and CFS >4 subgroup (P < 0.001).
Conclusions:
Frailty assessed by CFS was associated with CT-BC. CFS, CT-SS, and mGPS were associated with poorer survival in patients presenting as unscheduled admissions with CLTI. CT-SS and mGPS may contribute to part of frailty and prognostic assessment in this patient cohort
Dynamics of Simple Balancing Models with State Dependent Switching Control
Time-delayed control in a balancing problem may be a nonsmooth function for a
variety of reasons. In this paper we study a simple model of the control of an
inverted pendulum by either a connected movable cart or an applied torque for
which the control is turned off when the pendulum is located within certain
regions of phase space. Without applying a small angle approximation for
deviations about the vertical position, we see structurally stable periodic
orbits which may be attracting or repelling. Due to the nonsmooth nature of the
control, these periodic orbits are born in various discontinuity-induced
bifurcations. Also we show that a coincidence of switching events can produce
complicated periodic and aperiodic solutions.Comment: 36 pages, 12 figure
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