1,933 research outputs found
Platelets and galectins
A major function of platelets is keeping the vascular system intact. Platelet activation at sites of vascular injury leads to the formation of a hemostatic plug. Activation of platelets is therefore crucial for normal hemostasis; however, uncontrolled platelet activation may also lead to the formation of occlusive thrombi that can cause ischemic events. Although they are essential for proper hemostasis, platelet function extends to physiologic processes such as tissue repair, wound remodeling and antimicrobial host defense, or pathologic conditions such as thrombosis, atherosclerosis, chronic inflammatory diseases and cancer. Platelets can be activated by soluble molecules including thrombin, thromboxane A2 (TXA2), adenosine diphosphate (ADP), serotonin or by adhesive extracellular matrix (ECM) proteins such as von Willebrand factor (vWF) and collagen. Here we describe recent advances in the activation of platelets by non-canonical platelet agonists such as galectins. By acting either in soluble or immobilized form, these glycan-binding proteins trigger all platelet activation responses through modulation of discrete signaling pathways. We also offer new hypotheses and some speculations about the role of platelet-galectin interactions not only in hemostasis and thrombosis but also in inflammation and related diseases such as atherosclerosis and cancer.Fil: Schattner, Mirta Ana. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentin
Platelets: New bricks in the building of neutrophil extracellular traps
In addition to being key elements in hemostasis and thrombosis, platelets have an important role in the inflammatory and innate immune response. This activity is associated with their capability to recognize pathogens through the expression of toll-like receptors, the secretion of various cytokines, chemokines, and growth factors stored within their granules, and the expression of cell adhesion molecules that allows interaction with other immune cells, mainly neutrophils and monocytes. As part of the first line of defense, neutrophils control invading pathogens by phagocytosis, the release of antimicrobial proteins during degranulation, or through the formation of web-like structures named neutrophil extracellular traps (NETs). NETs are formed by chromatin, proteases, and antimicrobial proteins, and their main function is to trap and kill bacteria, virus, and fungi, avoiding their dissemination. Besides microorganisms, NET formation is also triggered by proinflammatory molecules and platelets. The uncontrolled formation of NETs might exert tissue damage and has been involved in a pathogenic mechanism of autoimmune and prothrombotic clinical conditions. In this review, we discuss the role of platelets in NET generation highlighting the mediators, stimuli, and molecular mechanisms involved in this phenomenon, both in human and murine models.Fil: Carestia, Agostina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Kaufman, Tomás. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Schattner, Mirta Ana. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentin
Competing Orders in a Nearly Antiferromagnetic Metal
We study the onset of spin-density wave order in itinerant electron systems
via a two-dimensional lattice model amenable to numerically exact,
sign-problem-free determinantal quantum Monte Carlo simulations. The
finite-temperature phase diagram of the model reveals a dome-shaped -wave
superconducting phase near the magnetic quantum phase transition. Above the
critical superconducting temperature, we observe an extended fluctuation
regime, which manifests itself in the opening of a gap in the electronic
density of states and an enhanced diamagnetic response. While charge density
wave fluctuations are moderately enhanced in the proximity of the magnetic
quantum phase transition, they remain short-ranged. The striking similarity of
our results to the phenomenology of many unconventional superconductors points
a way to a microscopic understanding of such strongly coupled systems in a
controlled manner
Superconductivity and non-Fermi liquid behavior near a nematic quantum critical point
Using determinantal quantum Monte Carlo, we compute the properties of a
lattice model with spin itinerant electrons tuned through a quantum
phase transition to an Ising nematic phase. The nematic fluctuations induce
superconductivity with a broad dome in the superconducting enclosing the
nematic quantum critical point. For temperatures above , we see strikingly
non-Fermi liquid behavior, including a "nodal - anti nodal dichotomy"
reminiscent of that seen in several transition metal oxides. In addition, the
critical fluctuations have a strong effect on the low frequency optical
conductivity, resulting in behavior consistent with "bad metal" phenomenology
Game Theory: The Modern-Day Airline Dogfight
This study examines the narrowing differentiation between legacy airlines and low-cost carriers in the United States by exploring the competitive strategies each group borrows from one another. Specifically, this work examines the implementation of a new type of economy fare by Delta Air Lines, called basic economy, and evaluates how the fare has impacted a key metric of airline performance: domestic operating revenues.
In the first part of this thesis, an explanation of the history behind airline marketing efforts as well as what constitutes a low-cost carrier and a legacy carrier is provided. A brief description of game theory is included as well.
In the second part of this thesis, domestic operating revenues were gathered from the Bureau of Transport Statistics for each of the legacy carriers in the United States: Delta Air Lines, United Airlines, and American Airlines. Since only Delta had implemented a basic economy fare at the time of this research, Delta was used as the test variable while American Airlines and United Airlines were used as control variables. A regression was then performed on the data to analyze the significance of the results and account for seasonality.
The data indicated that there was a strong correlation between Delta Air Lines’s growth in revenues and the introduction of its basic economy fare. Delta strongly outperformed its legacy airline competitors in domestic operating revenue growth during this time period. Now, American and United are following Delta’s lead and introducing their own versions of a basic economy class
Early-to-mid Pleistocene Tectonic Transition Across the Eastern Mediterranean Influences the Course of Human History
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