148 research outputs found
Thermal evolution of Uranus and Neptune I: adiabatic models
The brightness of Neptune is often found to be in accordance with an
adiabatic interior, while the low luminosity of Uranus challenges this
assumption. Here we apply revised equation of state data of hydrogen, helium,
and water and compute the thermal evolution of Uranus and Neptune assuming an
adiabatic interior. For this purpose, we have developed a new planetary model
and evolution code. We investigate the influence of albedo, solar energy
influx, and equations of state of H and He, and water on the cooling time. Our
cooling times of about for Uranus
and for Neptune bracket the known
age of the planets of implying that neither
planet's present-day luminosity can be explained by adiabatic cooling. We also
find that uncertainties on input parameters such as the level of irradiation
matter generally more for Uranus than for Neptune. Our results suggest that in
contrast to common assumptions, neither planet is fully adiabatic in the deeper
interior.Comment: Accepted for publication in A&A. Reproduced with permission from
Astronomy & Astrophysics, \copyright ES
Networked experiments and scientific resource sharing in cooperative knowledge spaces
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugĂ€nglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Cooperative knowledge spaces create new potentials for the experimental fields in natural sciences and engineering because they enhance the accessibility of experimental setups through virtual laboratories and remote technology, opening them for collaborative and distributed usage. A concept for extending existing virtual knowledge spaces for the means of the technological disciplines (âViCToRâSpacesâ â Virtual Cooperation in Teaching and Research for Mathematics, Natural Sciences and Engineering) is presented. The integration of networked virtual laboratories and remote experiments (âNanoLab Approachâ), as well as an approach to communityâdriven content sharing and content development within virtual knowledge spaces (NanoWiki) are described
Dénutrition chez les personnes ùgées vivant à domicile:: dans les soins à domicile, quels sont les outils de dépistage pertinents et probants de la dénutrition chez les personnes ùgées ? : travail de Bachelor
Dans le contexte de l'allongement de l'espĂ©rance de vie, les soins Ă domicile sont de plus en plus sollicitĂ©s pour la prise en soins des personnes ĂągĂ©es. Actuellement Ă GenĂšve, la dĂ©nutrition chez les personnes ĂągĂ©es est devenue un problĂšme socio-sanitaire. La population ĂągĂ©e de 65 ans et plus est Ă risque de dĂ©nutrition. Ces consĂ©quences peuvent aggraver l'Ă©tat de fragilitĂ© existant et ainsi compromettre le souhait de la personne Ă poursuivre sa vie Ă son domicile. Pour ces raisons, les infirmiĂšres de soins Ă domicile doivent ĂȘtre outillĂ©es pour dĂ©pister prĂ©cocement cette dĂ©nutrition. Ce travail a pour objectif de dĂ©terminer les outils probants pour dĂ©pister le risque de dĂ©nutrition chez les personnes ĂągĂ©es de 65 ans et plus vivant Ă domicile Ă GenĂšve
Bioactive Nanogels Mimicking the Antithrombogenic Nitric Oxide-Release Function of the Endothelium
Nitric oxide (NO) plays a significant role in controlling the physiology and pathophysiology of the body, including the endothelial antiplatelet function and therefore, antithrombogenic property of the blood vessels. This property of NO can be exploited to prevent thrombus formation on artificial surfaces like extracorporeal membrane oxygenators, which when come into contact with blood lead to protein adsorption and thereby platelet activation causing thrombus formation. However, NO is extremely reactive and has a very short biological half-life in blood, so only endogenous generation of NO from the blood contacting material can result into a stable and kinetically controllable local delivery of NO. In this regards, highly hydrophilic bioactive nanogels are presented which can endogenously generate NO in blood plasma from endogenous NO-donors thereby maintaining a physiological NO flux. It is shown that NO releasing nanogels could initiate cGMP-dependent protein kinase signaling followed by phosphorylation of vasodilator-stimulated phosphoprotein in platelets. This prevents platelet activation and aggregation even in presence of highly potent platelet activators like thrombin, adenosine 5âČ-diphosphate, and U46619 (thromboxane A2 mimetic)
Rebuilding the hematopoietic stem cell niche: Recent developments and future prospects
Hematopoietic stem cells (HSCs) have proven their clinical relevance in stem cell transplantation to cure patients with hematological disorders. Key to their regenerative potential is their natural microenvironment â their niche â in the bone marrow (BM). Developments in the field of biomaterials enable the recreation of such environments with increasing preciseness in the laboratory. Such artificial niches help to gain a fundamental understanding of the biophysical and biochemical processes underlying the interaction of HSCs with the materials in their environment and the disturbance of this interplay during diseases affecting the BM. Artificial niches also have the potential to multiply HSCs in vitro, to enable the targeted differentiation of HSCs into mature blood cells or to serve as drug-testing platforms. In this review, we will introduce the importance of artificial niches followed by the biology and biophysics of the natural archetype. We will outline how 2D biomaterials can be used to dissect the complexity of the natural niche into individual parameters for fundamental research and how 3D systems evolved from them. We will present commonly used biomaterials for HSC research and their applications. Finally, we will highlight two areas in the field of HSC research, which just started to unlock the possibilities provided by novel biomaterials, in vitro blood production and studying the pathophysiology of the niche in vitro. With these contents, the review aims to give a broad overview of the different biomaterials applied for HSC research and to discuss their potentials, challenges and future directions in the field.
Statement of significance
Hematopoietic stem cells (HSCs) are multipotent cells responsible for maintaining the turnover of all blood cells. They are routinely applied to treat patients with hematological diseases. This high clinical relevance explains the necessity of multiplication or differentiation of HSCs in the laboratory, which is hampered by the missing natural microenvironment â the so called niche. Biomaterials offer the possibility to mimic the niche and thus overcome this hurdle. The review introduces the HSC niche in the bone marrow and discusses the utility of biomaterials in creating artificial niches. It outlines how 2D systems evolved into sophisticated 3D platforms, which opened the gateway to applications such as, expansion of clinically relevant HSCs, in vitro blood production, studying niche pathologies and drug testing
Platelet Serotonin Aggravates Myocardial Ischemia/Reperfusion Injury via Neutrophil Degranulation
Background: Platelets store large amounts of serotonin that they release during thrombus formation or acute inflammation. This facilitates hemostasis and modulates the inflammatory response. Methods: Infarct size, heart function, and inflammatory cell composition were analyzed in mouse models of myocardial reperfusion injury with genetic and pharmacological depletion of platelet serotonin. These studies were complemented by in vitro serotonin stimulation assays of platelets and leukocytes in mice and men, and by measuring plasma serotonin levels and leukocyte activation in patients with acute coronary syndrome. Results: Platelet-derived serotonin induced neutrophil degranulation with release of myeloperoxidase and hydrogen peroxide (H2O2) and increased expression of membrane-bound leukocyte adhesion molecule CD11b, leading to enhanced inflammation in the infarct area and reduced myocardial salvage. In patients hospitalized with acute coronary syndrome, plasmatic serotonin levels correlated with CD11b expression on neutrophils and myeloperoxidase plasma levels. Long-term serotonin reuptake inhibition - reported to protect patients with depression from cardiovascular events - resulted in the depletion of platelet serotonin stores in mice. These mice displayed a reduction in neutrophil degranulation and preserved cardiac function. In line, patients with depression using serotonin reuptake inhibition, presented with suppressed levels of CD11b surface expression on neutrophils and lower myeloperoxidase levels in blood. Conclusions: Taken together, we identify serotonin as a potent therapeutic target in neutrophil-dependent thromboinflammation during myocardial reperfusion injury.Fil: Mauler, Maximilian. No especifĂca;Fil: Herr, Nadine. No especifĂca;Fil: Schoenichen, Claudia. No especifĂca;Fil: Witsch, Thilo. No especifĂca;Fil: Marchini, Timoteo Oscar. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de BioquĂmica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de BioquĂmica y Medicina Molecular; ArgentinaFil: HĂ€rdtner, Carmen. No especifĂca;Fil: Koentges, Christoph. No especifĂca;Fil: Kienle, Korbinian. Max Planck Institute Of Immunobiology And Epigenetics; AlemaniaFil: Ollivier, VĂ©ronique. Inserm; FranciaFil: Schell, Maximilian. No especifĂca;Fil: Dorner, Ludwig. No especifĂca;Fil: Wippel, Christopher. No especifĂca;Fil: Stallmann, Daniela. No especifĂca;Fil: Normann, Claus. No especifĂca;Fil: Bugger, Heiko. No especifĂca;Fil: Walther, Paul. Universitat Ulm; AlemaniaFil: Wolf, Dennis. La Jolla Institute for Allergy and Immunology; Estados UnidosFil: Ahrens, Ingo. No especifĂca;Fil: LĂ€mmermann, Tim. Max Planck Institute Of Immunobiology And Epigenetics; AlemaniaFil: Ho-Tin-NoĂ©, BenoĂźt. Inserm; FranciaFil: Ley, Klaus. La Jolla Institute for Allergy and Immunology; Estados UnidosFil: Bode, Christoph. No especifĂca;Fil: Hilgendorf, Ingo. No especifĂca;Fil: Duerschmied, Daniel. No especifĂca
DigitUS 1. Klausurtag | DigitUS Begleitmaterial. Handreichung fĂŒr LehrkrĂ€fte
Diese Handreichung fĂŒr LehrkrĂ€fte enthĂ€lt Information zur Organisation der Lerngemeinschaften und zum Projekt DigitUS. DarĂŒber hinaus werden die Struktur und die Inhalte des ersten Klausurtages aufgefĂŒhrt
Temporary antimetabolite treatment hold boosts SARS-CoV-2 vaccinationâspecific humoral and cellular immunity in kidney transplant recipients
Transplant recipients exhibit an impaired protective immunity after SARS-CoV-2 vaccination, potentially caused by mycophenolate (MPA) immunosuppression. Recent data from patients with autoimmune disorders suggest that temporary MPA hold might greatly improve booster vaccination outcomes. We applied a fourth dose of SARS-CoV-2 vaccine to 29 kidney transplant recipients during a temporary (5 weeks) MPA/azathioprine hold, who had not mounted a humoral immune response to previous vaccinations. Seroconversion until day 32 after vaccination was observed in 76% of patients, associated with acquisition of virus-neutralizing capacity. Interestingly, 21/25 (84%) calcineurin inhibitor-treated patients responded, but only 1/4 belatacept-treated patients responded. In line with humoral responses. counts and relative frequencies of spike receptor binding domain-specific (RBD-specific) B cells were markedly increased on day 7 after vaccination, with an increase in RBD-specific CD27(++)CD38(+) plasmablasts. Whereas overall proportions of spike-reactive CD4(+) T cells remained unaltered after the fourth dose, frequencies were positively correlated with specific IgG levels. Importantly, antigen-specific proliferating Ki67(+) and in vivo-activated programmed cell death 1-positive T cells significantly increased after revaccination during MPA hold, whereas cytokine production and memory differentiation remained unaffected. In summary, antimetabolite hold augmented all arms of immunity during booster vaccination. These data suggest further studies of antimetabolite hold in kidney transplant recipients
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