55 research outputs found
Synthetic photometry for carbon-rich giants. IV. An extensive grid of dynamic atmosphere and wind models
The evolution and spectral properties of stars on the AGB are significantly
affected by mass loss through dusty stellar winds. Dynamic atmosphere and wind
models are an essential tool for studying these evolved stars, both
individually and as members of stellar populations, to understand their
contribution to the integrated light and chemical evolution of galaxies.
This paper is part of a series testing state-of-the-art atmosphere and wind
models of carbon stars against observations, and making them available for use
in various theoretical and observational studies.
We have computed low-resolution spectra and photometry (in the wavelength
range 0.35-25 mu) for a grid of 540 dynamic models with stellar parameters
typical of solar-metallicity C-rich AGB stars and with a range of pulsation
amplitudes. The models cover the dynamic atmosphere and dusty outflow (if
present), assuming spherical symmetry, and taking opacities of gas-phase
species and dust grains consistently into account. To characterize the
time-dependent dynamic and photometric behaviour of the models in a concise way
we defined a number of classes for models with and without winds.
Comparisons with observed data in general show a quite good agreement for
example regarding mass-loss rates vs. (J-K) colours or K magnitudes vs. (J-K)
colours. Some exceptions from the good overall agreement, however, are found
and attributed to the range of input parameters (e.g. relatively high carbon
excesses) or intrinsic model assumptions (e.g. small particle limit for grain
opacities).
While current results indicate that some changes in model assumptions and
parameter ranges should be made in the future to bring certain synthetic
observables into better agreement with observations, it seems unlikely that
these pending improvements will significantly affect the mass-loss rates of the
models.Comment: 28 pages, 15 figures. Table B.1, an 11-page table, is only available
at CD
Ein Marshallplan mit Afrika: Geeignetes Konzept für eine nachhaltige Entwicklung?
Im Januar 2017 stellte Bundesminister Dr. Gerd Müller die Eckpunkte für den Marshallplan mit Afrika vor. Statt weiter Geld nach dem Gießkannenprinzip zu verteilen, soll zukünftig der Aufbau stabiler Wirtschaftsstrukturen gezielt gefördert und die Eigenverantwortung der Regierungen gestärkt werden. In seinem Beitrag stellt Bundesminister Gerd Müller den Marshallplan mit Afrika vor und unterstreicht, dass »eine Partnerschaft auf Augenhöhe« sowie eine verstärkte Mobilisierung privaten Kapitals und privater Investitionen erforderlich sei. Für Andreas Freytag und Susanne Fricke, Universität Jena, unterscheidet sich der aktuelle Marshallplan »wohltuend von althergebrachten Entwicklungsstrategien«. So betone er u.a. die Bedeutung der Wirtschaft für den Entwicklungsprozess Afrikas und mahne Investitionen, Bildung für die Jugend, die Einbindung in die Wertschöpfungsketten sowie die Schaffung eines Mittelstandes an. Ihm fehle aber eine definierte Schwerpunktsetzung. Franz Josef Radermacher, Universität Ulm und Club of Rome, beschreibt als Zielsetzung des Marshallplans eine »Wohlstandsexplosion in Afrika, insbesondere in Nordafrika«, die mit allen Nachhaltigkeitsanforderungen kompatibel gestaltet werden soll. Nach Meinung von Axel Dreher und Sarah Langlotz, Universität Heidelberg, sieht der Marshallplan mit Afrika eine Konzentration der Hilfe auf wenige reformwillige Länder vor, wodurch ärmere Länder an Unterstützung verlieren. Zudem betone der Plan Bedingungen, die an die deutschen Zahlungen geknüpft werden sollen. Detaillierte Bedingungen, von deren Einhaltung konkrete Hilfszahlungen abhängig gemacht werden, seien aber wenig sinnvoll. Deutschland solle sich stattdessen in Richtung einer bedingungslosen Budgethilfe bewegen. Werner Abelshauser, Universität Bielefeld, sieht den Marshallplan als Modell absolut ungeeignet, um Entwicklungsländer voranzubringen. Denn anders als in den meisten Empfängerländern Westeuropas nach dem Krieg fehle es dort gerade an Potenzial und wirtsch
Mechanism of polarization of Listeria monocytogenes surface protein ActA
The polar distribution of the ActA protein on the surface of the Gram-positive intracellular bacterial pathogen, Listeria monocytogenes, is required for bacterial actin-based motility and successful infection. ActA spans both the bacterial membrane and the peptidoglycan cell wall. We have directly examined the de novo ActA polarization process in vitro by using an ActA–RFP (red fluorescent protein) fusion. After induction of expression, ActA initially appeared at distinct sites along the sides of bacteria and was then redistributed over the entire cylindrical cell body through helical cell wall growth. The accumulation of ActA at the bacterial poles displayed slower kinetics, occurring over several bacterial generations. ActA accumulated more efficiently at younger, less inert poles, and proper polarization required an optimal balance between protein secretion and bacterial growth rates. Within infected host cells, younger generations of L. monocytogenes initiated motility more quickly than older ones, consistent with our in vitro observations of de novo ActA polarization. We propose a model in which the polarization of ActA, and possibly other Gram-positive cell wall-associated proteins, may be a direct consequence of the differential cell wall growth rates along the bacterium and dependent on the relative rates of protein secretion, protein degradation and bacterial growth
Profiling Microglia From Alzheimer's Disease Donors and Non-demented Elderly in Acute Human Postmortem Cortical Tissue
Microglia are the tissue-resident macrophages of the central nervous system (CNS). Recent studies based on bulk and single-cell RNA sequencing in mice indicate high relevance of microglia with respect to risk genes and neuro-inflammation in Alzheimer's disease (AD). Here, we investigated microglia transcriptomes at bulk and single-cell levels in non-demented elderly and AD donors using acute human postmortem cortical brain samples. We identified seven human microglial subpopulations with heterogeneity in gene expression. Notably, gene expression profiles and subcluster composition of microglia did not differ between AD donors and non-demented elderly in bulk RNA sequencing nor in single-cell sequencing
Perampanel as precision therapy in rare genetic epilepsies
OBJECTIVE: Perampanel, an antiseizure drug with α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor antagonist properties, may have a targeted effect in genetic epilepsies with overwhelming glutamate receptor activation. Epilepsies with loss of γ-aminobutyric acid inhibition (e.g., SCN1A), overactive excitatory neurons (e.g., SCN2A, SCN8A), and variants in glutamate receptors (e.g., GRIN2A) hold special interest. We aimed to collect data from a large rare genetic epilepsy cohort treated with perampanel, to detect possible subgroups with high efficacy.
METHODS: This multicenter project was based on the framework of NETRE (Network for Therapy in Rare Epilepsies), a web of pediatric neurologists treating rare epilepsies. Retrospective data from patients with genetic epilepsies treated with perampanel were collected. Outcome measures were responder rate (50% seizure reduction), and percentage of seizure reduction after 3 months of treatment. Subgroups of etiologies with high efficacy were identified.
RESULTS: A total of 137 patients with 79 different etiologies, aged 2 months to 61 years (mean = 15.48 ± 9.9 years), were enrolled. The mean dosage was 6.45 ± 2.47 mg, and treatment period was 2.0 ± 1.78 years (1.5 months-8 years). Sixty-two patients (44.9%) were treated for >2 years. Ninety-eight patients (71%) were responders, and 93 (67.4%) chose to continue therapy. The mean reduction in seizure frequency was 56.61% ± 34.36%. Sixty patients (43.5%) sustained >75% reduction in seizure frequency, including 38 (27.5%) with >90% reduction in seizure frequency. The following genes showed high treatment efficacy: SCN1A, GNAO1, PIGA, PCDH19, SYNGAP1, POLG1, POLG2, and NEU1. Eleven of 17 (64.7%) patients with Dravet syndrome due to an SCN1A pathogenic variant were responders to perampanel treatment; 35.3% of them had >90% seizure reduction. Other etiologies remarkable for >90% reduction in seizures were GNAO1 and PIGA. Fourteen patients had a continuous spike and wave during sleep electroencephalographic pattern, and in six subjects perampanel reduced epileptiform activity.
SIGNIFICANCE: Perampanel demonstrated high safety and efficacy in patients with rare genetic epilepsies, especially in SCN1A, GNAO1, PIGA, PCDH19, SYNGAP1, CDKL5, NEU1, and POLG, suggesting a targeted effect related to glutamate transmission
Perampanel as Precision Therapy in Rare Genetic Epilepsies
Objective: Perampanel, an antiseizure drug with AMPA-receptor antagonist properties, may have a targeted effect in genetic epilepsies with overwhelming glutamate receptor activation. Special interest holds epilepsies with loss of GABA inhibition (e.g. SCN1A), overactive excitatory neurons (e.g. SCN2A, SCN8A ), and variants in glutamate receptors (e.g. GRIN2A). We aimed to collect data from a large rare genetic epilepsy cohort treated with perampanel, to detect possible subgroups with high efficacy. Methods: A multicenter project based on the framework of NETRE (Network for Therapy in Rare Epilepsies), a web of pediatric neurologists treating rare epilepsies. Retrospective data from patients with genetic epilepsies treated with perampanel was collected. Outcome measures were responder rate (50% seizure reduction), and percentage of seizure reduction after 3 months of treatment. Subgroups of etiologies with high efficacy were identified. Results: 137 patients, with 79 different etiologies, aged 2 months-61 years (mean 15.48±9.9) were enrolled. The mean dosage was 6.45±2.47 mg, and treatment period was 2.0±1.78 years (1.5 months-8 years). 62 patients (44.9%) were treated for >2 years. 98 patients (71%) were responders, and 93 (67.4%) chose to continue therapy. The mean reduction in seizure frequency was 56.61±34.36%. 60 patients (43.5%) sustained over 75% reduction in seizure frequency, including 38 (27.5%) with > 90% reduction in seizure frequency. The following genes showed high treatment efficacy: SCN1A, GNAO1, PIGA, PCDH19, SYNGAP1, POLG1, POLG2, NEU1. 11/17 (64.7%) of patients with SCN1A, 35.3% of which had over 90% seizure reduction. Other etiologies remarkable for over 90% reduction in seizures were GNAO1 and PIGA. 14 patients had a CSWS EEG pattern and in 6 subjects perampanel reduced epileptiform activity. Significance: Perampanel demonstrated high safety and efficacy in patients with rare genetic epilepsies, especially in SCN1A, GNAO1, PIGA, PCDH19, SYNGAP1, CDKL5, NEU1 and POLG, suggesting a targeted effect related to glutamate transmission
Integrated care for older multimorbid heart failure patients:protocol for the ESCAPE randomized trial and cohort study
ESCAPE
Evaluation of a patient-centred biopsychosocial blended collaborative care pathway for the treatment of multimorbid elderly patients.
Therapeutic Area
Healthcare interventions for the management of older patients with multiple morbidities.
Aims
Multi-morbidity treatment is an increasing challenge for healthcare systems in ageing societies. This comprehensive cohort study with embedded randomized controlled trial tests an integrated biopsychosocial care model for multimorbid elderly patients.
Hypothesis
A holistic, patient-centred pro-active 9-month intervention based on the blended collaborative care (BCC) approach and enhanced by information and communication technologies can improve health-related quality of life (HRQoL) and disease outcomes as compared with usual care at 9 months.
Methods
Across six European countries, ESCAPE is recruiting patients with heart failure, mental distress/disorder plus ≥2 medical co-morbidities into an observational cohort study. Within the cohort study, 300 patients will be included in a randomized controlled assessor-blinded two-arm parallel group interventional clinical trial (RCT). In the intervention, trained care managers (CMs) regularly support patients and informal carers in managing their multiple health problems. Supervised by a clinical specialist team, CMs remotely support patients in implementing the treatment plan—customized to the patients' individual needs and preferences—into their daily lives and liaise with patients' healthcare providers. An eHealth platform with an integrated patient registry guides the intervention and helps to empower patients and informal carers.
HRQoL measured with the EQ-5D-5L as primary endpoint, and secondary outcomes, that is, medical and patient-reported outcomes, healthcare costs, cost-effectiveness, and informal carer burden, will be assessed at 9 and ≥18 months.
Conclusions
If proven effective, the ESCAPE BCC intervention can be implemented in routine care for older patients with multiple morbidities across the participating countries and beyond
Photosynthesis:ancient, essential, complex, diverse … and in need of improvement in a changing world
Alternatives to vitamin B 1 uptake revealed with discovery of riboswitches in multiple marine eukaryotic lineages
Vitamin B 1 (thiamine pyrophosphate, TPP) is essential to all life but scarce in ocean surface waters. In many bacteria and a few eukaryotic groups thiamine biosynthesis genes are controlled by metabolite-sensing mRNA-based gene regulators known as riboswitches. Using available genome sequences and transcriptomes generated from ecologically important marine phytoplankton, we identified 31 new eukaryotic riboswitches. These were found in alveolate, cryptophyte, haptophyte and rhizarian phytoplankton as well as taxa from two lineages previously known to have riboswitches (green algae and stramenopiles). The predicted secondary structures bear hallmarks of TPP-sensing riboswitches. Surprisingly, most of the identified riboswitches are affiliated with genes of unknown function, rather than characterized thiamine biosynthesis genes. Using qPCR and growth experiments involving two prasinophyte algae, we show that expression of these genes increases significantly under vitamin B 1 -deplete conditions relative to controls. Pathway analyses show that several algae harboring the uncharacterized genes lack one or more enzymes in the known TPP biosynthesis pathway. We demonstrate that one such alga, the major primary producer Emiliania huxleyi, grows on 4-amino-5-hydroxymethyl-2-methylpyrimidine (a thiamine precursor moiety) alone, although long thought dependent on exogenous sources of thiamine. Thus, overall, we have identified riboswitches in major eukaryotic lineages not known to undergo this form of gene regulation. In these phytoplankton groups, riboswitches are often affiliated with widespread thiamine-responsive genes with as yet uncertain roles in TPP pathways. Further, taxa with 'incomplete' TPP biosynthesis pathways do not necessarily require exogenous vitamin B 1, making vitamin control of phytoplankton blooms more complex than the current paradigm suggests. © 2014 International Society for Microbial Ecology. All rights reserved
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