High-accuracy Casimir-Polder force calculations using the Discontinuous Galerkin Time-Domain method

We describe a numerical time-domain approach for high-accuracy calculations of Casimir-Polder forces near micro-structured materials. The use of a time-domain formulation enables the investigation of a broad range of materials described by advanced material models, including nonlocal response functions. We validate the method by a number of example calculations for which we thoroughly investigate the convergence properties of the method, and comparing to analytical reference calculations, we find average relative errors as low as a few parts in a million. As an application example, we investigate the anisotropy-induced repulsive behavior of the Casimir-Polder force near a sharp gold wedge described by a hydrodynamic Drude model.Comment: 17 pages, 11 figure

Effect of pulsed delivery and bouillon base on saltiness and bitterness perceptions of salt delivery profiles partially substituted with KCl

Reducing salt levels in processed food is an important target for a growing numbers of food manufacturers. The effects of pulsed delivery (Dynataste) and bouillon base on saltiness and bitterness perception of partially substituted solutions (KCl) were investigated. Pulsed delivery did not enhance salt perception and resulted in greater Overall Bitterness Scores for the same level of substitution with KCl. The presence of the bouillon base masked to a certain extent the loss of saltiness induced by the substitution and resulted in lower Overall Bitterness Scores of the substituted profiles

Engagiert, engagierter... Fernstudent! Die Bedeutung von Ressourcen und Engagement im Fernstudium

Das Fernstudium stellt besondere Anforderungen an die Studierenden. Es fordert eine selbstregulierte Lernstruktur sowie ein Zeitmanagement, die es erlauben, Studium, Familie und Berufstätigkeit miteinander zu vereinen. Zudem sind meist mehrere Jahre zwischen Schule und Studium vergangen. So liegt die Vermutung nahe, dass gerade bei Studierenden an einer Fernuniversität das Engagement (Bakker, Schaufeli, Leiter & Taris, 2008) besonders bedeutsam ist. Für die Betrachtung dieses Sachverhaltes wurde die Utrecht Work Engagement Scale für Studierende (UWES-S) (Schaufeli, Martinez, Pinto, Salanova & Bakker, 2002) herangezogen. Mit deren Übersetzung ins Deutsche wurde das Studienengagement Fernunistudierenden untersucht. Ferner wurde die Grundannahme des Job-Demands-Resources-Modells (JD-R) (Schaufeli & Bakker, 2004; Bakker & Demerouti, 2007), dass Ressourcen einen durch Engagement vermittelten Einfluss auf den Studienerfolg besitzen (Hakanen, Schaufeli & Ahola, 2008), von uns auf den Studienkontext übertragen. Gerade für Fernstudierende interessante und relevante Ressourcen könnten z.B. die wahrgenommene allgemeine und studienkontextbezogene soziale Unterstützung, die Selbstwirksamkeitserwartung und die erlebte Autonomie bei der Einteilung des Studiums sein. In dieser Studie wurden von uns die folgenden Fragestellungen untersucht: Kann die Übersetzung und Anpassung der UWES-S für unseren Kontext als valide bezeichnet werden? Unterscheiden sich Fernstudierende von Studierenden an Präsenzuniversitäten im Engagement (unabhängig vom Alter)? Gibt es zwischen im Fernstudium relevanten Ressourcen und dem Studienerfolg einen Zusammenhang, der durch das Studienengagement vermittelt wird

The spatio-temporal organization of mitochondrial F1FO ATP synthase in cristae depends on its activity mode.

F1FO ATP synthase, also known as complex V, is a key enzyme of mitochondrial energy metabolism that can synthesize and hydrolyze ATP. It is not known whether the ATP synthase and ATPase function are correlated with a different spatio-temporal organisation of the enzyme. In order to analyze this, we tracked and localized single ATP synthase molecules in situ using live cell microscopy. Under normal conditions, complex V was mainly restricted to cristae indicated by orthogonal trajectories along the cristae membranes. In addition confined trajectories that are quasi immobile exist. By inhibiting glycolysis with 2-DG, the activity and mobility of complex V was altered. The distinct cristae-related orthogonal trajectories of complex V were obliterated. Moreover, a mobile subpopulation of complex V was found in the inner boundary membrane. The observed changes in the ratio of dimeric/monomeric complex V, respectively less mobile/more mobile complex V and its activity changes were reversible. In IF1-KO cells, in which ATP hydrolysis is not inhibited by IF1, complex V was more mobile, while inhibition of ATP hydrolysis by BMS-199264 reduced the mobility of complex V. Taken together, these data support the existence of different subpopulations of complex V, ATP synthase and ATP hydrolase, the latter with higher mobility and probably not prevailing at the cristae edges. Obviously, complex V reacts quickly and reversibly to metabolic conditions, not only by functional, but also by spatial and structural reorganization.This work was supported by the DFG (INST 190/167-2). K. Busch is associated with the CiM (Cells in Motion cluster, Munster).S

Lima1 mediates the pluripotency control of membrane dynamics and cellular metabolism.

Lima1 is an extensively studied prognostic marker of malignancy and is also considered to be a tumour suppressor, but its role in a developmental context of non-transformed cells is poorly understood. Here, we characterise the expression pattern and examined the function of Lima1 in mouse embryos and pluripotent stem cell lines. We identify that Lima1 expression is controlled by the naïve pluripotency circuit and is required for the suppression of membrane blebbing, as well as for proper mitochondrial energetics in embryonic stem cells. Moreover, forcing Lima1 expression enables primed mouse and human pluripotent stem cells to be incorporated into murine pre-implantation embryos. Thus, Lima1 is a key effector molecule that mediates the pluripotency control of membrane dynamics and cellular metabolism

LUBAC assembles a ubiquitin signaling platform at mitochondria for signal amplification and transport of NF-κB to the nucleus

Mitochondria are increasingly recognized as cellular hubs to orchestrate signaling pathways that regulate metabolism, redox homeostasis, and cell fate decisions. Recent research revealed a role of mitochondria also in innate immune signaling; however, the mechanisms of how mitochondria affect signal transduction are poorly understood. Here, we show that the NF-κB pathway activated by TNF employs mitochondria as a platform for signal amplification and shuttling of activated NF-κB to the nucleus. TNF treatment induces the recruitment of HOIP, the catalytic component of the linear ubiquitin chain assembly complex (LUBAC), and its substrate NEMO to the outer mitochondrial membrane, where M1- and K63-linked ubiquitin chains are generated. NF-κB is locally activated and transported to the nucleus by mitochondria, leading to an increase in mitochondria-nucleus contact sites in a HOIP-dependent manner. Notably, TNF-induced stabilization of the mitochondrial kinase PINK1 furthermore contributes to signal amplification by antagonizing the M1-ubiquitin-specific deubiquitinase OTULIN. Overall, our study reveals a role for mitochondria in amplifying TNF-mediated NF-κB activation, both serving as a signaling platform, as well as a transport mode for activated NF-κB to the nuclear

Obesity and the Risk of Cryptogenic Ischemic Stroke in Young Adults

Objectives: We examined the association between obesity and early-onset cryptogenic ischemic stroke (CIS) and whether fat distribution or sex altered this association. Materials and Methods: This prospective, multi-center, case-control study included 345 patients, aged 18-49 years, with first-ever, acute CIS. The control group included 345 age-and sex-matched stroke-free individuals. We measured height, weight, waist circumference, and hip circumference. Obesity metrics analyzed included body mass index (BMI), waist-to-hip ratio (WHR), waist-to-stature ratio (WSR), and a body shape index (ABSI). Models were adjusted for age, level of education, vascular risk factors, and migraine with aura. Results: After adjusting for demographics, vascular risk factors, and migraine with aura, the highest tertile of WHR was associated with CIS (OR for highest versus lowest WHR tertile 2.81, 95%CI 1.43-5.51; P=0.003). In sex-specific analyses, WHR tertiles were not associated with CIS. However, using WHO WHR cutoff values (>0.85 for women, >0.90 for men), abdominally obese women were at increased risk of CIS (OR 2.09, 95%CI 1.02-4.27; P=0.045). After adjusting for confounders, WC, BMI, WSR, or ABSI were not associated with CIS. Conclusions: Abdominal obesity measured with WHR was an independent risk factor for CIS in young adults after rigorous adjustment for concomitant risk factors.Peer reviewe