Observed crustal uplift near the Southern Patagonian Icefield constrains improved viscoelastic Earth model

Thirty‒one GPS geodetic measurements of crustal uplift in southernmost South America determined extraordinarily high trend rates (> 35 mm/yr) in the north‒central part of the Southern Patagonian Icefield. These trends have a coherent pattern, motivating a refined viscoelastic glacial isostatic adjustment model to explain the observations. Two end‒member models provide good fits: both require a lithospheric thickness of 36.5 ± 5.3 km. However, one end‒member has a mantle viscosity near η =1.6 ×1018 Pa s and an ice collapse rate from the Little Ice Age (LIA) maximum comparable to a lowest recent estimate of 1995–2012 ice loss at about −11 Gt/yr. In contrast, the other end‒member has much larger viscosity: η = 8.0 ×1018 Pa s, half the post–LIA collapse rate, and a steadily rising loss rate in the twentieth century after AD 1943, reaching −25.9 Gt/yr during 1995–2012.Fil: Lange, H.. Technische Universitaet Dresden; AlemaniaFil: Casassa, G.. Centro de Estudios Cientificos; Chile. Universidad de Magallanes; ChileFil: Ivins, E. R.. Institute of Technology. Jet propulsion Laboratory; Estados UnidosFil: Schroeder, L.. Technische Universitaet Dresden; AlemaniaFil: Fritsche, M.. Technische Universitaet Dresden; AlemaniaFil: Richter, Andreas Jorg. Technische Universitaet Dresden; Alemania. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas. Departamento de Astrometría; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Groh, A.. Technische Universitaet Dresden; AlemaniaFil: Dietrich, R.. Technische Universitaet Dresden; Alemani

Electro/magnetoencephalographic signatures of human brain insulin resistance

Human insulin action influences eating behavior, peripheral metabolism and cognition. Detailed insights into the neuronal processes related to human brain insulin action can be obtained by direct measures of neuronal activity with electroencephalography and magnetoencephalography. Results of recent studies show that spontaneous, task and stimulus related neuronal activity is modulated by insulin and that several factors like increased body weight and body composition can result in brain insulin resistance. Recent technological advances even allow the investigation of human brain functions in utero in relation to the metabolic status of the mother and indicate an effect of the mother’s insulin sensitivity on the brain function of the fetus. In conclusion, studies based on direct neuronal measurements may help to determine the developmental trajectory related to insulin action and resistance

Gene x Gene Interactions Highlight the Role of Incretin Resistance for Insulin Secretion

Introduction: Genetic polymorphisms in TCF7L2 are the strongest common risk variants for type 2 diabetes mellitus (T2D). We and others have shown that genetic variation in TCF7L2 and WFS1 affect incretin-stimulated insulin secretion. A recent genome-wide association study discovered genetic variants associated with incretin levels. We hypothesized that these SNPs (single nucleotide polymorphisms) interact with the well-known TCF7L2 variant rs7903146 on insulin secretion due to their incretin altering effect.Methods: In this retrospective analysis, we used data from the cross-sectional TUEF-cohort (n = 2929) and a hyperglycemic clamp study using additional GLP-1 infusion at the end of the clamp (n = 76). Insulin secretion was measured by evaluating OGTT-derived indexes of insulin secretion and insulin/C-peptide levels during clamp. We genotyped rs7903146 in TCF7L2, rs10010131 in WFS1, and six SNPs associated with GLP-1 and GIP levels.Results: One of the six incretin-associated SNPs, rs17681684 in GLP2R, exhibited significant SNP x SNP interactions with rs7903146 in TCF7L2 on insulin secretion (p = 0.0024) after correction for multiple testing. Three further SNP‘s showed nominally significant interactions (p < 0.05). In the hyperglycemic clamp study, rs7903146 in TCF7L2 also interacted with rs17681684 on AUC C-peptide during the GLP-1 stimulation phase, thereby replicating the above finding.Conclusion: The findings exemplify the role of SNP x SNP interactions in the genetics of type 2 diabetes mellitus and corroborate the existence of clinically relevant differences in incretin sensitivity

Analysis of the Release Characteristics of Cu-Treated Antimicrobial Implant Surfaces Using Atomic Absorption Spectrometry

New developments of antimicrobial implant surfaces doped with copper (Cu) ions may minimize the risk of implant-associated infections. However, experimental evaluation of the Cu release is influenced by various test parameters. The aim of our study was to evaluate the Cu release characteristics in vitro according to the storage fluid and surface roughness. Plasma immersion ion implantation of Cu (Cu-PIII) and pulsed magnetron sputtering process of a titanium copper film (Ti-Cu) were applied to titanium alloy (Ti6Al4V) samples with different surface finishing of the implant material (polished, hydroxyapatite and corundum blasted). The samples were submersed into either double-distilled water, human serum, or cell culture medium. Subsequently, the Cu concentration in the supernatant was measured using atomic absorption spectrometry. The test fluid as well as the surface roughness can alter the Cu release significantly, whereby the highest Cu release was determined for samples with corundum-blasted surfaces stored in cell medium

Sex-Specific Associations of Testosterone With Metabolic Traits

Background: Testosterone levels are differentially linked with diabetes risk in men and women: lower testosterone levels in men and higher testosterone levels in women are associated with type 2 diabetes, though, the mechanisms are not fully clear. We addressed sex-specific links between testosterone and major pathogenetic mechanisms of diabetes.Methods: We analyzed data of 623 subjects (202 male, 345 female without, and 76 female with oral contraceptive therapy [OCT]) for whom insulin sensitivity and insulin secretion were assessed by oral glucose tolerance test. Body fat percentage was assessed by bioelectrical impedance. Testosterone was measured by enzyme-linked immunoassay; free testosterone and Framingham risk score were calculated.Results: There were significant interactions between testosterone and sex for all tested metabolic traits. Increasing testosterone was associated with less body fat, elevated insulin sensitivity, and reduced glycemia, independent of adiposity in men. In women without OCT, testosterone correlated with more body fat, insulin resistance, and higher glucose concentrations. Testosterone was not associated with insulin secretion in either sex, but with lower Framingham risk score in men and higher Framingham risk score in women.Conclusions: Similar to diabetes risk, insulin resistance has different association directions with testosterone levels in males and females. Insulin resistance could therefore constitute the best biological candidate linking testosterone levels and diabetes prevalence. The question of antiandrogen therapy being able to improve metabolism, glucose tolerance and cardiovascular risk in women was not clarified in our study but should be reviewed with higher numbers in a carefully matched study to reduce the influence of confounding variables

Differential cellular metabolite alterations in HaCaT cells caused by exposure to the aryl hydrocarbon receptor-binding polycyclic aromatic hydrocarbons chrysene, benzo[a]pyrene and dibenzo[a,l]pyrene

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the human environment. Since they are present in crude oilfractions used for the production of rubber and plastics, consumers may come into direct dermal contacts with these compounds (e.g., via tool handles) on a daily basis. Some individual PAHs are identified as genotoxic mutagens thereby prompting particular toxicological and environmental concern. Among this group, benzo[a]pyrene (BAP) constitutes a model carcinogen which is also used as reference compound for risk assessment purposes. It acts as a strong agonist of the aryl hydrocarbon receptor (AHR) and becomes metabolically activated toward mutagenic and carcinogenic intermediates by cytochrome P450-dependent monooxygenases (CYPs). While BAP has been exhaustively characterized with regard to its toxicological properties, there is much less information available for other PAHs. We treated an AHR-proficient immortal human keratinocyte cell line (i.e., HaCaT) with three selected PAHs: BAP, chrysene (CRY) and dibenzo[a,l]pyrene (DALP). Compound-mediated alterations of endogenous metabolites were investigated by an LC–MS/MS-based targeted approach. To examine AHR-dependent changes of the measured metabolites, AHR-deficient HaCaT knockdown cells (AHR-KD) were used for comparison. Our results reveal that 24 metabolites are sufficient to separate the PAH-exposed cells from untreated controls by application of a multivariate model. Alterations in the metabolomics profiles caused by each PAH show influences on the energy and lipid metabolism of the cells indicating reduced tricarboxylic acid (TCA) cycle activity and β-oxidation. Up-regulation of sphingomyelin levels after exposure to BAP and DALP point to pro-apoptotic processes caused by these two potent PAHs. Our results suggest that in vitro metabolomics can serve as tool to develop bioassays for application in hazard assessment. Keywords: Polycyclic aromatic hydrocarbons, Metabolomics, Aryl hydrocarbon receptor, Keratinocyte

Weiterentwicklung des Analyseinstruments Renewbility: Renewbility II - Szenario für einen anspruchsvollen Klimaschutzbeitrag des Verkehrs

Das Projekt Renewbility II hatte zum Ziel den bestehenden Renewbility-Modellverbund weiterzuentwickeln und im Rahmen von Szenariobetrachtungen den möglichen Klimaschutzbeitrag des Verkehrssektors bis zum Jahr 2030 unter Mitwirkung unterschiedlichster gesellschaftlicher Akteure zu quantifizieren. Im Basisszenario werden bestehende Regulierungen im Verkehr berücksichtigt und bestehende Entwicklungen fortgeschrieben. Im Ergebnis können im Basisszenario bei deutlichen Effizienzsteigerungen, dem zunehmenden Einsatz alternativer Kraftstoffe im Verkehr und einer weiter zunehmenden Verkehrsnachfrage die Treibhausgasemissionen bis zum Jahr 2030 um 12 % gegenüber 2005 gesenkt werden. Im Klimaschutzszenario können mit deutlich ambitionierteren Maßnahmen die Treibhausgasemissionen im selben Zeitraum um 37 % reduziert werden bei gleichzeitiger Stärkung der deutschen Wirtschaftskraft und Stabilisierung des Staatshaushaltes. Neben einer weiteren Effizienzsteigerung und dem Einsatz von alternativen Antrieben und Kraftstoffen, trägt insbesondere die Verlagerung, aber auch die Vermeidung von Verkehren zur Emissionsminderung bei

Observed crustal uplift near the Southern Patagonian Icefield constrains improved viscoelastic Earth model

Thirty‒one GPS geodetic measurements of crustal uplift in southernmost South America determined extraordinarily high trend rates (> 35 mm/yr) in the north‒central part of the Southern Patagonian Icefield. These trends have a coherent pattern, motivating a refined viscoelastic glacial isostatic adjustment model to explain the observations. Two end‒member models provide good fits: both require a lithospheric thickness of 36.5 ± 5.3 km. However, one end‒member has a mantle viscosity near η =1.6 ×1018 Pa s and an ice collapse rate from the Little Ice Age (LIA) maximum comparable to a lowest recent estimate of 1995–2012 ice loss at about −11 Gt/yr. In contrast, the other end‒member has much larger viscosity: η = 8.0 ×1018 Pa s, half the post–LIA collapse rate, and a steadily rising loss rate in the twentieth century after AD 1943, reaching −25.9 Gt/yr during 1995–2012.Facultad de Ciencias Astronómicas y Geofísica

Cholesterol Synthesis Is Associated with Hepatic Lipid Content and Dependent on Fructose/Glucose Intake in Healthy Humans

Visceral obesity and fatty liver have been related to high synthesis and low absorption of cholesterol. This study aimed to investigate the associations of cholesterol metabolism with liver and visceral fat content in healthy humans. Another objective was to explore the effects of very-high-fructose and very-high-glucose diets on cholesterol homeostasis. We report on a cohort of 20 people (12 males, 8 females; age 30.5 ± 2.0 years; body mass index 25.9 ± 0.5 kg/m2) who completed a four-week dietary intervention study. Between the baseline and the followup examination the study participants in addition to a balanced weight-maintaining diet received 150 g of either fructose or glucose per day. Visceral and liver fat were measured with magnetic resonance (MR) imaging and 1H-MR spectroscopy, respectively. Cholesterol absorption and synthesis were estimated from the serum noncholesterol sterol concentrations. Performing cross-sectional analyses the lanosterol and desmosterol to cholesterol ratios were positively correlated with visceral and liver fat content (all P < .03). The lathosterol to cholesterol ratio decreased in response to high-fructose diet (P = .006) but not in response to high-glucose diet. To conclude, visceral and liver fat content are associated with cholesterol synthesis in healthy humans. Furthermore, cholesterol synthesis appears to be dependent on fructose/glucose intake