9 research outputs found

    Importance of Insulin Immunoassays in the Diagnosis of Factitious Hypoglycemia

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    We report two cases emphasizing the importance of insulin assays for evaluation of hypoglycemia in diabetic patients. Case 1 was a 9(6/12)-year-old female patient with type 1 diabetes mellitus and case 2 was a 10(10/12)-year-old male patient with DIDMOAD. Both patients were on a basal-bolus insulin regimen. Both were admitted because of persistent hypoglycemia. Analyses of serum samples obtained at the time of hypoglycemia initially showed low insulin and C-peptide levels. Recurrent episodes of unexplained hypoglycemia necessitated measurement of insulin levels by using different insulin assays, which revealed hyperinsulinemic hypoglycemia with low C-peptide levels, findings which confirmed a diagnosis of factitious hypoglycemia. Surreptitious administration of insulin should not be excluded in diabetic patients with hypoglycemia without taking into account the rate of cross-reactivity of insulin analogues with the insulin assay used

    Antioxidant activity of an anatolian herbal tea—Origanum minutiflorum: isolation and characterization of its secondary metabolites

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    Origanum species are significant aromatic and medicinal plants used in food and pharmaceutical industries. Isolation of bioactive compounds was executed on n-butanol extract to yield the compounds responsible for the activities. Tricosan-1-ol (1), (8E,16E)-tetracosa-8,16-diene-1,24-diol (2), azepan-2-one (3), 3,4-dihydroxybenzoic acid (4), apigenin (5), eriodictyol (6), globoidnan-A (7), luteolin (8), rosmarinic acid (9), apigenin-7-O-glucuronide (10), and vicenin-2 (11) were isolated by chromatographic methods (column chromatography and semi-preparative High Performance Liquid Chromatography (HPLC) and structures were elucidated on the basis of spectroscopic techniques including 1D/2D nuclear magnetic resonance (NMR) and Liquid chromatography/Time-of-flight/Mass spectrometry (LC-TOF/MS). The isolated compounds and extracts were applied for antioxidant assays including 1,1-diphenyl-2-picrylhydrazyl (DPPH•) scavenging, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS•+) scavenging, reducing power, and cuprac techniques. 3,4-Dihydroxy benzoic acid (4), eriodictyol (6), luteolin (8), and rosmarinic acid (9) revealed the considerable antioxidant activities

    Water Impact Resistant and Antireflective Superhydrophobic Surfaces Fabricated by Spray Coating of Nanoparticles: Interface Engineering via End-Grafted Polymers

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    Fully transparent and water impact resistant superhydrophobic coatings are of great importance for a range of applications including photovoltaics, photonics, automotive windshields, and building windows. A widely utilized approach to fabricate such coatings involves solution-based deposition of hydrophobic nanoparticles. A central challenge is that these coatings do not simultaneously offer high levels of water repellency, perfect transparence, and water impact resistance. Here we demonstrate that end-grafted polymers present excellent interfaces for spray-coated hydrophobic nanoparticles and enable fabrication of water impact resistant and antireflective superhydrophobic coatings (SHPARCs). Depending on the backbone chemistry and thickness, end-grafted polymers uniquely interacted with the fluorinated nanoparticles, resulting in nanostructured films that provided reduction of reflective losses and protection from the impact of water droplets. Counterintuitively, substrates modified with end-grafted hydrophilic polymers exhibited high water impact resistance: the sliding angle of SHPARC on 12 nm thick end-grafted poly(ethylene glycol) layer was <2 degrees after exposure to 100000 water droplets. SHPARC increased the transparency of the glass substrate by similar to 5% through omnidirectional antireflectivity. We finally demonstrate application of SHPARC on a large area (156 x 156 mm(2)) silicon solar cell without significant (<0.23%) reduction of the power conversion efficiency, illustrating the promise of the presented approach in fabrication of self-cleaning photovoltaic modules

    Sustainable and Practical Superhydrophobic Surfaces via Mechanochemical Grafting

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    Abstract The broad adoption of superhydrophobic surfaces in practical applications is hindered by limitations of existing methods in terms of excessive usage of solvents, the need for tedious and lengthy chemical processes, insufficient biocompatibility, and the high cost of materials. Herein, a mechanochemical approach for practical and solvent‐free manufacturing of superhydrophobic surfaces is reported. This approach enables solvent‐free and ultra‐rapid preparation of superhydrophobic surfaces in a single‐step without the need for any washing, separation, and drying steps. The hydrolytic rupture of siloxane bonds and generation of free radicals induced by mechanochemical pathways play a key role in covalent grafting of silicone to the surface of nanoparticles that leads to superhydrophobic surfaces with a water contact angle of >165° and a sliding angle of <2°. The direct use of industrially available and non‐functional silicone materials together with demonstrated applicability to inorganic nanoparticles of varied composition greatly contribute to the scalability of the presented approach. The resulting superhydrophobic surfaces are highly biocompatible as demonstrated by fibroblast cells using two different assays. Monolith materials fabricated from silicone‐grafted nanoparticles exhibit bulk and durable superhydrophobicity. The presented approach offers tremendous potential with sustainability, scalability, cost‐effectiveness, simplicity, biocompatibility, and universality

    Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins

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    Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains

    Data Descriptor: A European Multi Lake Survey dataset of environmental variables, phytoplankton pigments and cyanotoxins

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    Under ongoing climate change and increasing anthropogenic activity, which continuously challenge ecosystem resilience, an in-depth understanding of ecological processes is urgently needed. Lakes, as providers of numerous ecosystem services, face multiple stressors that threaten their functioning. Harmful cyanobacterial blooms are a persistent problem resulting from nutrient pollution and climate-change induced stressors, like poor transparency, increased water temperature and enhanced stratification. Consistency in data collection and analysis methods is necessary to achieve fully comparable datasets and for statistical validity, avoiding issues linked to disparate data sources. The European Multi Lake Survey (EMLS) in summer 2015 was an initiative among scientists from 27 countries to collect and analyse lake physical, chemical and biological variables in a fully standardized manner. This database includes in-situ lake variables along with nutrient, pigment and cyanotoxin data of 369 lakes in Europe, which were centrally analysed in dedicated laboratories. Publishing the EMLS methods and dataset might inspire similar initiatives to study across large geographic areas that will contribute to better understanding lake responses in a changing environment

    Poster presentations.

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