571 research outputs found
Many Masses on One Stroke: Economic Computation of Quark Propagators
The computational effort in the calculation of Wilson fermion quark
propagators in Lattice Quantum Chromodynamics can be considerably reduced by
exploiting the Wilson fermion matrix structure in inversion algorithms based on
the non-symmetric Lanczos process. We consider two such methods: QMR (quasi
minimal residual) and BCG (biconjugate gradients). Based on the decomposition
of the Wilson mass matrix, using QMR, one can carry
out inversions on a {\em whole} trajectory of masses simultaneously, merely at
the computational expense of a single propagator computation. In other words,
one has to compute the propagator corresponding to the lightest mass only,
while all the heavier masses are given for free, at the price of extra storage.
Moreover, the symmetry can be used to cut
the computational effort in QMR and BCG by a factor of two. We show that both
methods then become---in the critical regime of small quark
masses---competitive to BiCGStab and significantly better than the standard MR
method, with optimal relaxation factor, and CG as applied to the normal
equations.Comment: 17 pages, uuencoded compressed postscrip
Spatial Besov Regularity for Stochastic Partial Differential Equations on Lipschitz Domains
We use the scale of Besov spaces B^\alpha_{\tau,\tau}(O), \alpha>0,
1/\tau=\alpha/d+1/p, p fixed, to study the spatial regularity of the solutions
of linear parabolic stochastic partial differential equations on bounded
Lipschitz domains O\subset R^d. The Besov smoothness determines the order of
convergence that can be achieved by nonlinear approximation schemes. The proofs
are based on a combination of weighted Sobolev estimates and characterizations
of Besov spaces by wavelet expansions.Comment: 32 pages, 3 figure
Peptide-based solutions to reduce undesired cell culture media chemistry – New options for stabilized media formulations
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Design Dimensions for Enterprise-Wide Data Management: A Chief Data Officer’s Journey
To unlock additional business value, most enterprises are intensifying their enterprise-wide data management. In the case of the globally operating bank, we base this article on, a Chief Data Officer (CDO) organization is established for providing data governance and, in a second step, pushing data driven innovation forward. As many employees of the bank were not yet familiar with (or did not acknowledge) the need for enterprise-wide data management, this evolution exhibits characteristics of an organizational learning process. CDOs may want to actively steer this learning process by purposefully designing and adjusting their data management approach over time. Based on the major controversies the CDO has been confronted with, we propose four design dimensions for enterprise-wide data management and discuss the considerations for their configuration: (I) objective, (II) governance, (III) organization of data analytics, and (IV) expertise
Promotion and growth diagrams for fans of Dyck paths and vacillating tableaux
We construct an injection from the set of -fans of Dyck paths (resp.
vacillation tableaux) of length into the set of chord diagrams on
that intertwines promotion and rotation. This is done in two different ways,
namely as fillings of promotion--evacuation diagrams and in terms of Fomin
growth diagrams. Our analysis uses the fact that -fans of Dyck paths and
vacillating tableaux can be viewed as highest weight elements of weight zero in
crystals of type and , respectively, which in turn can be analyzed
using virtual crystals. On the level of Fomin growth diagrams, the
virtualization process corresponds to Krattenthaler's blow up construction. One
of the motivations for finding rotation invariant diagrammatic bases such as
chord diagrams is the cyclic sieving phenomenon. Indeed, we give a cyclic
sieving phenomenon on -fans of Dyck paths and vacillating tableaux using the
promotion action.Comment: 40 pages, 13 figure
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Passive Immunization against Pyroglutamate-3 Amyloid-β Reduces Plaque Burden in Alzheimer-Like Transgenic Mice: A Pilot Study
Background: N-terminally truncated and modified pyroglutamate-3 amyloid-β protein (pE3-Aβ) is present in most, if not all, cerebral plaque and vascular amyloid deposits in human Alzheimer's disease (AD). pE3-Aβ deposition is also found in AD-like transgenic (tg) mouse brain, albeit in lesser quantities than general Aβ. pE3-Aβ resists degradation, is neurotoxic, and may act as a seed for Aβ aggregation. Objective: We sought to determine if pE3-Aβ removal by passive immunization with a highly specific monoclonal antibody (mAb) impacts pathogenesis in a mouse model of Alzheimer's amyloidosis. Methods: APPswe/PS1ΔE9 tg mice were given weekly intraperitoneal injections of a new anti-pE3-Aβ mAb (mAb07/1) or PBS from 5.8 to 13.8 months of age (prevention) or from 23 to 24.7 months of age (therapeutic). Multiple forms of cerebral Aβ were quantified pathologically and biochemically. Gliosis and microhemorrhage were examined. Results: Chronic passive immunization with an anti-pE3-Aβ mAb significantly reduced total plaque deposition and appeared to lower gliosis in the hippocampus and cerebellum in both the prevention and therapeutic studies. Insoluble Aβ levels in hemibrain homogenates were not significantly different between immunized and control mice. Microhemorrhage was not observed with anti-pE3-Aβ immunotherapy. Conclusions: Selective removal of pE3-Aβ lowered general Aβ plaque deposition suggesting a pro-aggregation or seeding role for pE3-Aβ
COVID-19 und Lebererkrankungen
Bis zu 53 % der PatientInnen mit Coronavirus Disease 2019 (COVID-19) weisen eine hepatische Beteiligung auf. Durch die Expression der Hauptzielstruktur für „severe acute respiratory syndrome coronavirus type 2“ (SARS-CoV-2), des Angiotensin-converting-Enzym-2(ACE2)-Rezeptors, auch auf Cholangiozyten, sinusoidalen Endothelzellen und Hepatozyten kann es zu einer direkten Schädigung der Leber kommen. Ferner spielt eine indirekte (nicht durch Rezeptoren vermittelte) Schädigung der Leber im Rahmen von COVID-19 durch eine schwere systemische Inflammation mit Zytokinsturm, hepatischen Thrombosen und einer systemischen Hypoxie eine wichtige Rolle. Bei COVID-19 gelten Leberwerte als wichtige Prädiktoren für die Prognose der PatientInnen. Wichtig ist es hierbei Differenzialdiagnosen für die Leberwerterhöhung, wie andere Virusinfektionen, medikamentös-toxisch induzierte Leberschädigung sowie autoimmune, metabolische und andere Lebererkrankungen, abzuklären. Von hoher klinischer Relevanz für die Behandlung kritisch kranker PatientInnen auf der Intensivstation ist das Krankheitsbild der „secondary sclerosing cholangitis in critically ill patients“ (SSC-CIP). Hierfür sind unter anderem hochdosierte Katecholamine, eine Beatmung mit hohem positivem endexspiratorischem Druck (PEEP) und die extrakorporale Membranoxygenierung (ECMO) Risikofaktoren. Eine frühe Diagnose dieser Erkrankung und Behandlung mittels interventioneller endoskopischer retrograder Cholangiographie (ERC) ist hierbei von entscheidender Bedeutung. Auch sollte eine Lebertransplantation evaluiert werden. Bei einer COVID-19-Erkrankung treten Fälle mit SSC, sog. COVID-SSC, auf. Die COVID-SSC und die SSC-CIP sind im klinischen Phänotyp, Risikofaktoren, Prognose und transplantatfreien Überleben vergleichbar. PatientInnen mit vorbestehender Lebererkrankung haben kein erhöhtes Risiko für eine Infektion mit SARS-CoV‑2, erkranken jedoch schwerer an COVID-19 als PatientInnen ohne Lebervorerkrankungen. Bei PatientInnen mit einer vorbestehenden Leberzirrhose kann eine SARS-CoV-2-Infektion ein akut-auf-chronisches Leberversagen (ACLF) induzieren. Hierbei handelt es sich um ein Krankheitsbild mit einer sehr hohen Mortalität, das im Rahmen einer intensivmedizinischen Behandlung therapiert werden muss.
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In patients with coronavirus disease 2019 (COVID-19), hepatic involvement occurs in up to 53% of all cases. Via the primary target for severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), the angiotensin-converting enzyme 2 (ACE2) receptor, expressed on cholangiocytes, sinusoidal endothelial cells, and hepatocytes, direct damage to the liver may occur. Furthermore, indirect (= not receptor-mediated) damage to the liver plays a crucial role in the context of COVID-19 due to severe systemic inflammation with cytokine storm, hepatic thrombosis, and systemic hypoxia. In COVID-19, liver enzymes are considered significant predictors of outcome. Thus, it is essential to rule out other causes of liver enzyme elevation, such as other viral infections, drug-induced liver injury, and metabolic, autoimmune and other liver diseases. Secondary sclerosing cholangitis in critically ill patients (SSC-CIP) is highly relevant in treating critically ill patients in the intensive care unit (ICU). Risk factors for SSC-CIP include high doses of catecholamines, high positive end-expiratory pressure (PEEP), and extracorporeal membrane oxygenation (ECMO) therapy. Early recognition of this disease and treatment by endoscopic retrograde cholangiography (ERC) is crucial. Furthermore, liver transplantation should be evaluated. Some patients with COVID-19 are diagnosed with SSC, which is termed COVID-19-associated SSC. COVID-19-associated SSC and SSC-CIP are comparable with regard to clinical phenotype, risk factors, prognosis, and graft-free survival. Patients with pre-existing liver disease are not at increased risk for infection with SARS-CoV‑2 but show more severe clinical courses of COVID-19 than patients without pre-existing liver disease. Patients with pre-existing liver cirrhosis may develop acute-on-chronic liver failure (ACLF) upon infection with SARS-CoV‑2. ACLF has a high mortality rate, which must be treated in the ICU
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