133 research outputs found

    Characterization of Solar Radiation-Induced Degradation Products of the Plant Sunscreen Sinapoyl Malate

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    Agricultural activities at lower temperatures lead to lower yields due to reduced plant growth. Applying photomolecular heater agrochemicals could boost yields under these conditions, but UV-induced degradation of these compounds needs to be assessed. In this study, we employ liquid chromatography-mass spectrometry (LC-MS) coupled with infrared ion spectroscopy (IRIS) to detect and identify the degradation products generated upon simulated solar irradiation of sinapoyl malate, a proposed photomolecular heater/UV filter compound. All major irradiation-induced degradation products are identified in terms of their full molecular structure by comparing the IRIS spectra obtained after LC fractionation and mass isolation with reference IR spectra obtained from quantum-chemical calculations. In cases where physical standards are available, a direct experimental-to-experimental comparison is possible for definitive structure identification. We find that the major degradation products originate from trans-to-cis isomerization, ester cleavage, and esterification reactions of sinapoyl malate. Preliminary in silico toxicity investigations using the VEGAHUB platform suggest no significant concerns for these degradation products’ human and environmental safety. The identification workflow presented here can analogously be applied to break down products from other agrochemical compounds. As the method records IR spectra with the sensitivity of LC-MS, application to agricultural samples, e.g., from field trials, is foreseen.</p

    Cerebral small vessel disease in elderly patients with vestibular neuritis

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    Background: Acute audiovestibular loss is a neurotologic emergency of which the etiology is frequently unknown. In vestibular neuritis a viral genesis is expected, although there is insufficient evidence to support viruses as the only possible etiological factor. In sudden deafness, a vascular etiology has been proposed in elderly patients, since cardiovascular risk factors are more frequently present and a higher risk of developing a stroke was seen compared to the general population. So far, very little research has been carried out on vascular involvement in elderly patients with vestibular neuritis. Cardiovascular risk factors have a positive correlation with cerebral small vessel disease, visible as white matter hyperintensities, brain infarctions, microbleeds and lacunes on MRI. The presence of these characteristics indicate a higher risk of developing a stroke. Aim: We investigated whether elderly patients with vestibular neuritis have a higher prevalence of vascular lesions on MRI compared to a control cohort. Materials and Methods: Patients of 50-years and older, diagnosed with vestibular neuritis in a multidisciplinary tertiary referral hospital, were retrospectively reviewed and compared to a control cohort. The primary outcome was the difference in cerebral small vessel disease on MRI imaging, which was assessed by the number of white matter hyperintensities using the ordinal Fazekas scale. Secondary outcomes were the presence of brain infarctions on MRI and the difference in cardiovascular risk factors. Results: Patients with vestibular neuritis (N = 101) had a 1.60 higher odds of receiving a higher Fazekas score than the control cohort (N = 203) (p = 0.048), there was no difference in presence of brain infarctions (p = 1.0). Hyperlipidemia and atrial fibrillation were more common in patients experiencing vestibular neuritis. Conclusion: We found a positive correlation of white matter hyperintensities and VN which supports the hypothesis of vascular involvement in the pathophysiology of vestibular neuritis in elderly patients. Further prospective research is necessary to confirm this correlation.Disorders of the head and nec

    Rolled-Up Nanotech: Illumination-Controlled Hydrofluoric Acid Etching of AlAs Sacrificial Layers

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    <p>Abstract</p> <p>The effect of illumination on the hydrofluoric acid etching of AlAs sacrificial layers with systematically varied thicknesses in order to release and roll up InGaAs/GaAs bilayers was studied. For thicknesses of AlAs below 10 nm, there were two etching regimes for the area under illumination: one at low illumination intensities, in which the etching and releasing proceeds as expected and one at higher intensities in which the etching and any releasing are completely suppressed. The &#8220;etch suppression&#8221; area is well defined by the illumination spot, a feature that can be used to create heterogeneously etched regions with a high degree of control, shown here on patterned samples. Together with the studied self-limitation effect, the technique offers a way to determine the position of rolled-up micro- and nanotubes independently from the predefined lithographic pattern.</p

    FLAME DEPOSITION AND CHARACTERIZATION OF LARGE TYPE-IIA DIAMOND SINGLE-CRYSTALS

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    Contains fulltext : 112639.pdf (publisher's version ) (Open Access

    The influence of differences in gas phase between turbulent and laminar acetylene-oxygen combustion flames on diamond growth

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    Contains fulltext : 28126.pdf (publisher's version ) (Open Access

    Single crystal diamond deposition by laminar and turbulent acetylene-oxygen flames

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    Contains fulltext : 28128___.PDF (publisher's version ) (Open Access

    Orientation dependent surface stabilization on flame deposited diamond single crystals

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    Contains fulltext : 28129.pdf (publisher's version ) (Open Access

    Relation between gas phase CN radical distributions, nitrogen incorporation, and growth rate in flame deposition of diamond

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    Contains fulltext : 112624.pdf (publisher's version ) (Open Access
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