66 research outputs found
Signatures of phase transitions in the microwave response of YbRh2Si2
We used a spectroscopic microwave technique utilizing superconducting
stripline resonators at frequencies between 3 GHz and 15 GHz to examine the
charge dynamics of YbRh2Si2 at temperatures and magnetic fields close to the
quantum critical point. The different electronic phases of this heavy-fermion
compound, in particular the antiferromagnetic, Fermi-liquid, and
non-Fermi-liquid regimes, were probed with temperature-dependent microwave
measurements between 40 mK and 600 mK at a set of different magnetic fields up
to 140 mT. Signatures of phase transitions were observed, which give
information about the dynamic response of this peculiar material that exhibits
field-tuned quantum criticality and pronounced deviations from Fermi-liquid
theory.Comment: 5 pages, 3 figure
Open-Cellular Alumina Foams with Hierarchical Strut Porosity by Ice Templating: A Thickening Agent Study
Alumina replica foams were manufactured by the Schwartzwalder sponge replication technique and were provided with an additional strut porosity by a freeze-drying/ice-templating step prior to thermal processing. A variety of thickeners in combination with different alumina solid loads in the dispersion used for polyurethane foam template coating were studied. An additional strut porosity as generated by freeze-drying was found to be in the order of ~20%, and the spacings between the strut pores generated by ice-templating were in the range between 20 µm and 32 µm. In spite of the lamellar strut pore structure and a total porosity exceeding 90%, the compressive strength was found to be up to 1.3 MPa. Combining the replica process with freeze-drying proves to be a suitable method to enhance foams with respect to their surface area accessible for active coatings while preserving the advantageous flow properties of the cellular structure. A two-to-threefold object surface-to-object volume ratio of 55 to 77 mm−1 was achieved for samples with 30 vol% solid load compared to 26 mm−1 for non-freeze-dried samples. The freeze-drying technique allows the control of the proportion and properties of the introduced pores in an uncomplicated and predictable way by adjusting the process parameters. Nevertheless, the present article demonstrates that a suitable thickener in the dispersion used for the Schwartzwalder process is inevitable to obtain ceramic foams with sufficient mechanical strength due to the necessarily increased water content of the ceramic dispersion used for foam manufacturing
Near-real time oculodynamic MRI: a feasibility study for evaluation of diplopia in comparison with clinical testing
Objective: To demonstrate feasibility of near-real-time oculodynamic magnetic resonance imaging (od-MRI) in depicting extraocular muscles and correlate quantitatively the motion degree in comparison with clinical testing in patients with diplopia. Methods: In 30 od-MRIs eye movements were tracked in the horizontal and sagittal plane using a a TrueFISP sequence with high temporal resolution. Three physicians graded the visibility of extraocular muscles by a qualitative scale. In 12 cases, the maximal monocular excursions in the horizontal and vertical direction of both eyes were measured in od-MRIs and a clinical test and correlated by the Pearson test. Results: The medial and lateral rectus muscles were visible in the axial plane in 93% of the cases. The oblique, superior and inferior rectus muscles were overall only in 14% visible. Horizontal (p = 0,015) and vertical (p = 0,029) movements of the right eye and vertical movement of the left eye (p = 0,026) measured by od-MRI correlated positively to the clinical measurements. Conclusions: Od-MRI is a feasible technique. Visualization of the horizontal/vertical rectus muscles is better than for the superior/inferior oblique muscle. Od-MRI correlates well with clinical testing and may reproduce the extent of eye bulb motility and extraocular muscle structural or functional deteriorations. Key Points • Oculodynamic MRI technique helps clinicians to assess eye bulb motility disorders • MRI evaluation of eye movement provides functional information in cases of diplopia • Oculodynamic MRI reproduces excursion of extraocular muscles with good correlation with clinical testing • Dynamic MRI sequence supplements static orbital protocol for evaluation of motility disorder
Association of Klotho protein levels and KL-VS heterozygosity with Alzheimer disease and amyloid and tau burden
Importance Identification of proteins and genetic factors that reduce Alzheimer disease (AD) pathology is of importance when searching for novel AD treatments. Heterozygosity of the KL-VS haplotype has been associated with reduced amyloid and tau burden. Whether this association is mediated by the Klotho protein remains unclear.
Objectives To assess concentrations of Klotho in cerebrospinal fluid (CSF) and plasma among cognitively healthy controls and patients with AD and to correlate these findings with KL-VS heterozygosity status and amyloid and tau burden.
Design, Setting, and Participants This case-control study combined 2 independent case-control AD cohorts consisting of 243 referred patients with AD and volunteer controls recruited from January 1, 2009, to December 31, 2018. Klotho levels were measured in CSF and plasma and correlated with KL-VS heterozygosity status and levels of CSF amyloid-β 42 (Aβ42), total tau, and phosphorylated tau. Statistical analysis was performed from January 1, 2021, to March 1, 2022.
Main Outcomes and Measures Associations of Klotho levels in CSF and plasma with levels of CSF biomarkers were analyzed using linear regression. Association analyses were stratified separately by clinical groups, APOE4 status, and KL-VS heterozygosity. Pearson correlation was used to assess the correlation between CSF and plasma Klotho levels.
Results A total of 243 participants were included: 117 controls (45 men [38.5%]; median age, 65 years [range, 41-84 years]), 102 patients with mild cognitive impairment due to AD (AD-MCI; 59 men [57.8%]; median age, 66 years [range, 46-80 years]), and 24 patients with dementia due to AD (AD-dementia; 12 men [50.0%]; median age, 64.5 years [range, 54-75 years]). Median CSF Klotho levels were higher in controls (1236.4 pg/mL [range, 20.4-1726.3 pg/mL]; β = 0.103; 95% CI, 0.023-0.183; P = .01) and patients with AD-MCI (1188.1 pg/mL [range, 756.3-1810.3 pg/mL]; β = 0.095; 95% CI, 0.018-0.172; P = .02) compared with patients with AD-dementia (1073.3 pg/mL [range, 698.2-1661.4 pg/mL]). Higher levels of CSF Klotho were associated with lower CSF Aβ42 burden (β = 0.519; 95% CI, 0.201-0.836; P < .001) and tau burden (CSF total tau levels: β = −0.884; 95% CI, 0.223 to −0.395; P < .001; CSF phosphorylated tau levels: β = −0.672; 95% CI, −1.022 to −0.321; P < .001) independent of clinical, KL-VS heterozygosity, or APOE4 status. There was a weak correlation between Klotho CSF and plasma levels among the entire cohort (Pearson correlation r = 0.377; P < .001).
Conclusions and Relevance The findings of this case-control study suggest that Klotho protein levels were associated with clinical stages of AD, cognitive decline, and amyloid and tau burden and that these outcomes were more clearly mediated by the protein directly rather than the KL-VS heterozygosity variant. When selecting individuals at risk for clinical trials, the Klotho protein level and not only the genetic profile should be considered
Helden in der Schule. Akten der Tagung Kloster Banz 2014
Ausgehend von der Feststellung, dass die Integration mittelalterlicher Texte im Deutschunterricht in der Schulpraxis weitgehend ein Desiderat darstellt, präsentierten Beitragende aus Schule und Wissenschaft bei der Tagung „Helden in der Schule“ im Oktober 2014 ihre Projekte und Ideen zu und Erfahrungen mit der Implementation germanistisch-mediävistischer Inhalte im Deutschunterricht. Dabei reichen die Beiträge von allgemeinen Überlegungen zum Nutzen mittelalterlicher Literatur in der Schule über konkrete Unterrichtsentwürfe bis hin zur Umsetzung in der Waldorfschule und der Integration schulbezogener Lehrveranstaltungen in der Universität. Bei aller Verschiedenheit in den Herangehensweisen wird in allen Beiträgen eindrucksvoll deutlich gemacht, dass mittelalterliche Literatur auch im 21. Jahrhundert überaus lohnend in die Unterrichtspraxis einbezogen werden kann.Since medieval texts are not treated enough in school, lecturers working in school and university presented their projects, ideas and experiences concerning the implementation of German-mediavistic contents in German school lessons during the conference “Heroes in School” in October 2014. The topics concern general reflection about the profitability of medieval literature in school, concrete lesson plans, the implementation in Rudolf Steiner schools, the integration of seminars in university that deal with the work in school etc. All articles demonstrate that the integration of medieval literature in school worth the effort – also in the 21st century
Neil3-dependent base excision repair regulates lipid metabolism and prevents atherosclerosis in Apoe-deficient mice
Increasing evidence suggests that oxidative DNA damage accumulates in atherosclerosis. Recently, we showed that a genetic variant in the human DNA repair enzyme NEIL3 was associated with increased risk of myocardial infarction. Here, we explored the role of Neil3/NEIL3 in atherogenesis by both clinical and experimental approaches. Human carotid plaques revealed increased NEIL3 mRNA expression which significantly correlated with mRNA levels of the macrophage marker CD68. Apoe−/−Neil3−/− mice on high-fat diet showed accelerated plaque formation as compared to Apoe−/− mice, reflecting an atherogenic lipid profile, increased hepatic triglyceride levels and attenuated macrophage cholesterol efflux capacity. Apoe−/−Neil3−/− mice showed marked alterations in several pathways affecting hepatic lipid metabolism, but no genotypic alterations in genome integrity or genome-wide accumulation of oxidative DNA damage. These results suggest a novel role for the DNA glycosylase Neil3 in atherogenesis in balancing lipid metabolism and macrophage function, potentially independently of genome-wide canonical base excision repair of oxidative DNA damage
DNA glycosylase Neil3 regulates vascular smooth muscle cell biology during atherosclerosis development.
BACKGROUND AND AIMS: Atherogenesis involves a complex interaction between immune cells and lipids, processes greatly influenced by the vascular smooth muscle cell (VSMC) phenotype. The DNA glycosylase NEIL3 has previously been shown to have a role in atherogenesis, though whether this is due to its ability to repair DNA damage or to other non-canonical functions is not yet clear. Hereby, we investigate the role of NEIL3 in atherogenesis, specifically in VSMC phenotypic modulation, which is critical in plaque formation and stability. METHODS: Chow diet-fed atherosclerosis-prone Apoe-/- mice deficient in Neil3, and NEIL3-abrogated human primary aortic VSMCs were characterized by qPCR, and immunohistochemical and enzymatic-based assays; moreover, single-cell RNA sequencing, mRNA sequencing, and proteomics were used to map the molecular effects of Neil3/NEIL3 deficiency in the aortic VSMC phenotype. Furthermore, BrdU-based proliferation assays and Western blot were performed to elucidate the involvement of the Akt signaling pathway in the transdifferentiation of aortic VSMCs lacking Neil3/NEIL3. RESULTS: We show that Neil3 deficiency increases atherosclerotic plaque development without affecting systemic lipids. This observation was associated with a shift in VSMC phenotype towards a proliferating, lipid-accumulating and secretory macrophage-like cell phenotype, without changes in DNA damage. VSMC transdifferentiation in Neil3-deficient mice encompassed increased activity of the Akt signaling pathway, supported by cell experiments showing Akt-dependent proliferation in NEIL3-abrogated human primary aortic VSMCs. CONCLUSIONS: Our findings show that Neil3 deficiency promotes atherosclerosis development through non-canonical mechanisms affecting VSMC phenotype involving activation of the Akt signaling pathway
The EnMAP spaceborne imaging spectroscopy mission: Initial scientific results two years after launch
Transcriptional Response of Zebrafish Embryos Exposed to Neurotoxic Compounds Reveals a Muscle Activity Dependent hspb11 Expression
Acetylcholinesterase (AChE) inhibitors are widely used as pesticides and drugs. Their primary effect is the overstimulation of cholinergic receptors which results in an improper muscular function. During vertebrate embryonic development nerve activity and intracellular downstream events are critical for the regulation of muscle fiber formation. Whether AChE inhibitors and related neurotoxic compounds also provoke specific changes in gene transcription patterns during vertebrate development that allow them to establish a mechanistic link useful for identification of developmental toxicity pathways has, however, yet not been investigated. Therefore we examined the transcriptomic response of a known AChE inhibitor, the organophosphate azinphos-methyl (APM), in zebrafish embryos and compared the response with two non-AChE inhibiting unspecific control compounds, 1,4-dimethoxybenzene (DMB) and 2,4-dinitrophenol (DNP). A highly specific cluster of APM induced gene transcripts was identified and a subset of strongly regulated genes was analyzed in more detail. The small heat shock protein hspb11 was found to be the most sensitive induced gene in response to AChE inhibitors. Comparison of expression in wildtype, ache and sopfixe mutant embryos revealed that hspb11 expression was dependent on the nicotinic acetylcholine receptor (nAChR) activity. Furthermore, modulators of intracellular calcium levels within the whole embryo led to a transcriptional up-regulation of hspb11 which suggests that elevated intracellular calcium levels may regulate the expression of this gene. During early zebrafish development, hspb11 was specifically expressed in muscle pioneer cells and Hspb11 morpholino-knockdown resulted in effects on slow muscle myosin organization. Our findings imply that a comparative toxicogenomic approach and functional analysis can lead to the identification of molecular mechanisms and specific marker genes for potential neurotoxic compounds
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