Institute For Chemie Und Bioanalytik
Institute For Chemie Und Bioanalytik
Rossetti F.F.,University of Zürich |
Siegmann K.,University of Zürich |
Koser J.,Institute For Chemie Und Bioanalytik |
Wegner I.,Institute For Chemie Und Bioanalytik |
And 3 more authors.
International Journal of Polymer Science | Year: 2017
Selected mono- A nd bicationic quats were compounded with polyethylene. The physicochemical surface properties, leaching behavior, and antibacterial activity of such modified samples were investigated. Contact angle measurements and fluorescein binding assays showed the presence of quaternary ammonium groups at the surface. After storing the samples in 50°C warm water for 30 days, several were still antimicrobially active. No correlation between the number of exposed N+ head groups after leaching and the antibacterial activity was observed. There is however a qualitative correlation of the antibacterial activity with the contact angles and surface concentrations of N+ before leaching/storing in warm water. © 2017 Fernanda F. Rossetti et al.
Steinbauer V.,University of Bern |
Kaufmann J.,Empa - Swiss Federal Laboratories for Materials Science and Technology |
Zurbriggen R.,Akzo Nobel |
Buhler T.,Institute For Chemie Und Bioanalytik |
Herwegh M.,University of Bern
International Journal of Impact Engineering | Year: 2017
Hail impact damage on External Thermal Insulation Systems (ETICS) is increasingly recognized by insurance companies owing to increased storm occurrence frequency and storm intensity. To develop hail resistant ETICS for houses and better understand existing admission tests, high-speed-camera recordings of ice ball impacts at an angle of 45° and steel ball impacts at angles of 90° and 45° were used to characterize the impact process and to derivate the damaging mechanisms of impacts on facades. Recorded surface deformation is characterized by high indentation depth of the impactor and high flexural bending causing high surface parallel strain. Analyses of the impact process allowed the identification of the mechanisms and timing of fracture formation in different regions. Additionally, differences in the impact process of the European steel ball impact test (90°, ETAG 004) and the Swiss ice ball impact test (45°, VKF P. No 8) are discussed in detail. Caused by the difference in impact angle, the 45° ice ball impacts lead to lower indentation depth and consequently to lower tensile strain and damage. However, surface parallel movement of the impactor caused the formation of an elongated damage pattern in the 45° impacts. To avoid the observed brittle failure behavior, the development of flexible materials with the ability to elastically accommodate impact strains is favorable to reduce hail stone impact damage. © 2017
Allemann C.,University of Applied Sciences and Arts Western Switzerland |
Marti R.,University of Applied Sciences and Arts Western Switzerland |
Vorlet O.,University of Applied Sciences and Arts Western Switzerland |
Martin O.,ZHAW Zurich University of Applied Sciences |
And 7 more authors.
Chimia | Year: 2017
This article provides an overview of activities in the fields of continuous processes, flow chemistry and microreactors at the Universities of Applied Sciences in Switzerland. © Swiss Chemical Society
Doessegger L.,Hoffmann-La Roche |
Schmitt G.,Hoffmann-La Roche |
Lenz B.,Hoffmann-La Roche |
Fischer H.,Hoffmann-La Roche |
And 7 more authors.
Therapeutic Advances in Drug Safety | Year: 2013
Background: Phospholipidosis (PLD) is a lysosomal storage disorder induced by a class of cationic amphiphilic drugs. However, drug-induced PLD is reversible. Evidence of PLD from animal studies with some compounds has led to discontinuation of development. Regulatory authorities are likely to request additional studies when PLD is linked to toxicity. Objective: We conducted a trial to investigate urinary phenylacetylglycine (uPAG) as a biomarker for PLD. Materials and methods: Five groups of 12 male Wistar rats were dosed once with vehicle, 300 mg/kg or 1500 mg/kg of compound A (known to induce PLD), or 300 mg/kg or 1000 mg/ kg of compound B (similar structure, but does not induce PLD) to achieve similar plasma exposures. Following dosing, urine and blood samples underwent nuclear magnetic resonance (NMR), proteomic, and biochemical analyses. Necropsies were performed at 48 and 168 h, organ histopathology evaluated, and gene expression in liver analyzed by microarray. Electron microscopic examination of peripheral lymphocytes was performed. Results: For compound A, uPAG increased with dose, correlating with lamellar inclusion bodies formation in peripheral lymphocytes. NMR analysis showed decreased tricarboxylic acid cycle intermediates, inferring mitochondrial toxicity. Mitochondrial dysfunction was suggested by uPAG increase, resulting from a switch to anaerobic metabolism or disruption of the urea cycle. Discussion and conclusion: uPAG shows utility as a noninvasive biomarker for mitochondrial toxicity associated with drug-induced PLD, providing a mechanistic hypothesis for toxicity associated with PLD likely resulting from combined direct and indirect mitochondrial toxicity via impairment of the proton motor force and alteration of fatty acid catabolism. © The Author(s), 2013.
Braun A.,Empa - Swiss Federal Laboratories for Materials Science and Technology |
Chen Q.,Empa - Swiss Federal Laboratories for Materials Science and Technology |
Chen Q.,ETH Zurich |
Flak D.,Empa - Swiss Federal Laboratories for Materials Science and Technology |
And 19 more authors.
ChemPhysChem | Year: 2012
Anodization of α-Fe 2O 3 (hematite) electrodes in alkaline electrolyte under constant potential conditions the electrode surface in a way that an additional current wave occurs in the cyclic voltammogram. The energy position of this current wave is closely below the potential of the anodization treatment. Continued cycling or exchanging of the electrolyte causes depletion of this new feature. The O 1s and Fe 2p core-level X-ray photoelectron spectra (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectra of such conditioned hematite exhibit a chemical shift towards higher binding energies, in line with the general perception that anodization generates oxide species with dielectric properties. The valence band XPS and particularly the iron resonant valence band photoemission spectra, however, are shifted towards the opposite direction, that is, towards the Fermi energy, suggesting that hole doping on hematite has taken place during anodization. Quantitative analysis of the Fe 2p resonant valence band photoemission spectra shows that the spectra obtained at the Fe 2p absorption threshold are shifted by virtually the same energy as the anodization potential towards the Fermi energy. The tentative interpretation of this observation is that anodization forms a surface film on the hematite that is specific to the anodization potential. © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Noser J.,Kantonales Laboratorium Basel Landschaft |
Schneider P.,Kantonales Laboratorium Basel Landschaft |
Rother M.,Institute For Chemie Und Bioanalytik |
Schmutz H.,Institute For Chemie Und Bioanalytik
Mycotoxin Research | Year: 2011
An ultra performance liquid chromatography (UPLC)-tandem mass spectrometry (MS/MS) method was developed for the determination of the Alternaria toxins tenuazonic acid, alternariol, alternariol monomethyl ether, altenuene, altertoxin I and tentoxin. Owing to its instability, altenusin could not be determined. The sample preparation includes an acidic acetonitrile/water/ methanol extraction, followed by SPE clean-up step, before injection into the UPLC-MS/MS system. The separation was made on an Acquity UPLC column using a water/acetonitrile gradient with ammonium hydrogen carbonate as a modifier. Matrix compounds of real samples led to enhancement as well as suppression of the target compounds, depending on analyte and matrix. The recoveries were between 58 and 109% at a level of 10 μg/kg. Eighty-five tomato products, consisting of peeled and minced tomatoes, soup and sauces, tomato purées and concentrates, ketchup as well as dried and fresh tomatoes, were taken from the Swiss market in 2010. Tenuazonic acid was found most frequently (81 out of 85 samples) and in the highest levels of up to 790 μg/kg. Alternariol and alternariol monomethyl ether were found in lower concentrations, ranging from <1 to 33 μg/kg for alternariol and <5 to 9 μg/kg for alternariol monomethyl ether. Only a few samples were positive for altenuene and tentoxin. Altertoxin I was never detected. © 2011 Society for Mycotoxin Research and Springer.
Glaied O.,Institute For Chemie Und Bioanalytik |
Delaite C.,Upper Alsace University |
Bistac S.,Upper Alsace University
Polymer International | Year: 2014
The degree of crystallinity of poly(ε-caprolactone)-block-poly(vinyl acetate) (PCL-b-PVAc) block copolymers is determined as a function of PCL molecular weight for PCL-alkyne homopolymers and PCL-b-PVAc copolymers obtained via a click reaction. Poly(ε-caprolactone)-block-poly(vinyl acetate) (PCL-b-PVAc) block copolymers were synthesized using two approaches: a 'coupling' approach using click chemistry reaction and a 'macroinitiator' route. Different copolymers, varying by their block lengths, were prepared with both methods. PCL is a semi-crystalline polymer, and consequently PCL blocks of PCL-b-PVAc are able to crystallize. The purpose of this work was to analyse the influence of the method of copolymer synthesis on the crystallinity of the PCL blocks. The results indicate a significant decrease of the crystallinity of the PCL blocks in copolymers obtained using the coupling method, compared to PCL homopolymers, in contrast to copolymers obtained through the macroinitiator approach for which the crystallinity of PCL is much less affected. This influence of the synthesis method is explained by the presence, in the copolymers obtained using the click reaction, of a rigid triazol cycle binding the two blocks, limiting their mobility and decreasing the tendency of PCL to crystallize. © 2013 Society of Chemical Industry.
Tarasov A.,University of Basel |
Wipf M.,University of Basel |
Bedner K.,Paul Scherrer Institute |
Kurz J.,Institute For Chemie Und Bioanalytik |
And 7 more authors.
Langmuir | Year: 2012
Conventional gate oxide layers (e.g., SiO 2, Al 2O 3, or HfO 2) in silicon field-effect transistors (FETs) provide highly active surfaces, which can be exploited for electronic pH sensing. Recently, great progress has been achieved in pH sensing using compact integrateable nanowire FETs. However, it has turned out to be much harder to realize a true reference electrode, which - while sensing the electrostatic potential - does not respond to the proton concentration. In this work, we demonstrate a highly effective reference sensor, a so-called reference FET, whose proton sensitivity is suppressed by as much as 2 orders of magnitude. To do so, the Al 2O 3 surface of a nanowire FET was passivated with a self-assembled monolayer of silanes with a long alkyl chain. We have found that a full passivation can be achieved only after an extended period of self-assembling lasting several days at 80 °C. We use this slow process to measure the number of active proton binding sites as a function of time by a quantitative comparison of the measured nonlinear pH-sensitivities to a theoretical model (site-binding model). Furthermore, we have found that a partially passivated surface can sense small changes in the number of active binding sites reaching a detection limit of δN s ≈ 170 μm -2Hz -1/2 at 10 Hz and pH 3. © 2012 American Chemical Society.
Spies P.,Institute For Chemie Und Bioanalytik |
Mueller R.,Institute For Chemie Und Bioanalytik |
Chen G.J.,NCL New Concept Laboratory |
Gygax D.,Institute For Chemie Und Bioanalytik
Analytical Biochemistry | Year: 2010
In this article, we describe a new enzyme-linked immunosorbent assay (ELISA) setup to improve the sensitivity of commercial or homemade ELISAs. In the new ELISA setup, an IMAPlate 5RC96, a disposable multi-utility lab device developed by NCL New Concept Lab is used as a self-uptaking microcuvette array to read out the result of the ELISA that is performed in the normal 96-well plate with reduced substrate solution and stop solution. A commercial interleukin-6 (IL-6) ELISA reagent kit was used for the evaluation. Compared with the conventional ELISA setup, the new ELISA setup could easily increase the absorbance values by up to more than 10-fold. Therefore, the sensitivity (change in absorbance/change in concentration [ΔAbs/ΔConc]) is increased accordingly. In addition, methods to extend the upper detection limit of plate readers for the IMAPlate 5RC96 are described. This new ELISA setup may be more notable for the approach employed than for the specific analyte. It should generally be applicable to any conventional ELISA and should serve as an example of a simple solution that increases the detection sensitivity and/or detection range of other assays as well. We expect the approach to have a substantial practical impact on analytical methods and to accelerate discovery, research, and application of analytes at low concentration in life sciences and diagnostics. © 2009 Elsevier Inc. All rights reserved.
PubMed | Institute For Chemie Und Bioanalytik
Type: Comparative Study | Journal: Analytical biochemistry | Year: 2010
In this article, we describe a new enzyme-linked immunosorbent assay (ELISA) setup to improve the sensitivity of commercial or homemade ELISAs. In the new ELISA setup, an IMAPlate 5RC96, a disposable multi-utility lab device developed by NCL New Concept Lab is used as a self-uptaking microcuvette array to read out the result of the ELISA that is performed in the normal 96-well plate with reduced substrate solution and stop solution. A commercial interleukin-6 (IL-6) ELISA reagent kit was used for the evaluation. Compared with the conventional ELISA setup, the new ELISA setup could easily increase the absorbance values by up to more than 10-fold. Therefore, the sensitivity (change in absorbance/change in concentration [DeltaAbs/DeltaConc]) is increased accordingly. In addition, methods to extend the upper detection limit of plate readers for the IMAPlate 5RC96 are described. This new ELISA setup may be more notable for the approach employed than for the specific analyte. It should generally be applicable to any conventional ELISA and should serve as an example of a simple solution that increases the detection sensitivity and/or detection range of other assays as well. We expect the approach to have a substantial practical impact on analytical methods and to accelerate discovery, research, and application of analytes at low concentration in life sciences and diagnostics.