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Search Results: 1 - 10 of 4826 matches for " Marcus Baumann "
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Advanced glycation endproducts in sepsis and mechanical ventilation: extra or leading man?
Marcus Baumann
Critical Care , 2009, DOI: 10.1186/cc7939
Abstract: The advanced glycation endproduct (AGE) Nε-carboxy-methyllysine (CML), as recently investigated by Kneyber and colleagues [1], can be formed either from glucose via ketoamine or glyoxal or from lipids by oxidation via glyoxal. This may explain why the pathophysiological role of AGEs is not restricted to diabetes, in which condition they have been primarily studied [2].The enhanced formation of AGEs results in enhanced urinary excretion. In this context, renal-insufficient patients have been associated with CML values several times higher than in healthy controls. Accumulating AGEs can be observed histologically as endothelial depositions in atherosclerotic plaques and tubular cells [3-5]. Their deposition initiates increased NADPH oxidase and nuclear factor κB activity as well as a reduction in endothelial nitric oxide synthase activity [6]. These major effects cause inflammatory changes, extracellular matrix accumulation and endothelial dysfunction. Therefore, AGE accumulation is a potential target for treating inflammatory diseases.The new and interesting idea of Kneyber and colleagues was to investigate the association of CML with myocardial inflammation during sepsis and the clinically relevant state of mechanical ventilation, which by itself is known to induce AGE accumulation in the lungs. This is of relevance as sepsis-induced cardiac dysfunction is a frequent complication associated with increased mortality. Therefore, they focused on a situation where AGE accumulation is increased by systemic inflammation and exacerbated by mechanical ventilation. The association of CML with myocardial inflammation in sepsis and mechanical ventilation is intriguing. Indeed, sepsis enhances CML deposition, which is further aggravated by mechanical ventilation. Thus, the myocardial deposition of AGEs is associated with the disease and the therapeutic approach of mechanical ventilation perpetuates AGE formation.These results raise the question, however, whether the association
A laboratory incubator equipped with facilities to automatically simulate natural irradiance
Aletsee, Ludwig;Baumann, Marcus E. M.;
Boletim do Instituto Oceanográfico , 1991, DOI: 10.1590/S0373-55241991000200006
Abstract: an incubator is described which automatically simulates fluctuations of natural irradiance by coupling a photocell to a lightbank in the ship's laboratory. design details are given.
A laboratory incubator equipped with facilities to automatically simulate natural irradiance
Aletsee, Ludwig;Baumann, Marcus E. M;
Brazilian Journal of Oceanography , 1991, DOI: 10.1590/S1679-87591991000200006
Abstract: an incubator is described which automatically simulates fluctuations of natural irradiance by coupling a photocell to a lightbank in the ship's laboratory. design details are given.
Open Photoacoustic Cell for Blood Sugar Measurement: Numerical Calculation of Frequency Response
Bernd Baumann,Marcus Wolff,Mark Teschner
Physics , 2015,
Abstract: A new approach for continuous and non-invasive monitoring of the glucose concentration in human epidermis has been suggested recently. This method is based on photoacoustic (PA) analysis of human interstitial fluid. The measurement can be performed in vitro and in vivo and, therefore, may form the basis for a non-invasive monitoring of the blood sugar level for diabetes patients. It requires a windowless PA cell with an additional opening that is pressed onto the human skin. Since signals are weak, advantage is taken of acoustic resonances of the cell. Recently, a numerical approach based on the Finite Element (FE) Method has been successfully used for the calculation of the frequency response function of closed PA cells. This method has now been adapted to obtain the frequency response of the open cell. Despite the fact that loss due to sound radiation at the opening is not included, fairly good accordance with measurement is achieved.
Organic residues in lake and drinking water from the lagoa de Juturnaíba (regi?o dos lagos - RJ, Brazil)
Stumpf, Marcus;Haberer, Klaus;Rodrigues, Silvana V.;Baumann, Wolfram;
Journal of the Brazilian Chemical Society , 1997, DOI: 10.1590/S0103-50531997000500012
Abstract: various analytical methods for the determination of organic residues in water were applied to samples from the lagoa de juturnaíba in the regi?o dos lagos, east of rio de janeiro. the concentrations of more than 60 pesticides and of different aminopolycarboxylic acids were determined using gc/ms detection, and a gc/ms screening procedure was applied to detect additional compounds. none of the investigated pesticide residues could be detected in the lake water at detection limits of less than 100 ng/l. edta was detected at a concentration level of 2 mg/l in the lake and in drinking water prepared from this lake. traces of biphenyl were identified by gc/ms in the lake water, the source of which may be its use in impregnating citrus fruit packaging. the drinking water produced from the lake by two different water treatment plants was investigated with respect to disinfection by-products (dbps), such as chlorinated organic acids. the concentration of the investigated dbps was as high as 180 mg/l in one sample. the aox of this sample was 428 g/l.
An overview of the key routes to the best selling 5-membered ring heterocyclic pharmaceuticals
Marcus Baumann,Ian R. Baxendale,Steven V. Ley,Nikzad Nikbin
Beilstein Journal of Organic Chemistry , 2011, DOI: 10.3762/bjoc.7.57
Abstract: This review presents a comprehensive overview on selected synthetic routes towards commercial drug compounds as published in both journal and patent literature. Owing to the vast number of potential structures, we have concentrated only on those drugs containing five-membered heterocycles and focused principally on the assembly of the heterocyclic core. In order to target the most representative chemical entities the examples discussed have been selected from the top 200 best selling drugs of recent years.
Numerical Investigation of Symmetry Breaking and Critical Behavior of the Acoustic Streaming Field in High-Intensity Discharge Lamps
Bernd Baumann,Joerg Schwieger,Marcus Wolff,Freddy Manders,Jos Suijker
Physics , 2014,
Abstract: For energy efficiency and material cost reduction it is preferred to drive high-intensity discharge lamps at frequencies of approximately 300 kHz. However, operating lamps at these high frequencies bears the risk of stimulating acoustic resonances inside the arc tube, which can result in low frequency light flicker and even lamp destruction. The acoustic streaming effect has been identified as the link between high frequency resonances and low frequency flicker. A highly coupled 3D multiphysics model has been set up to calculate the acoustic streaming velocity field inside the arc tube of high-intensity discharge lamps. It has been found that the velocity field suffers a phase transition to an asymmetrical state at a critical acoustic streaming force. The system behaves similar to a ferromagnet near the Curie point. Furthermore, it is discussed how the model allows to investigate the light flicker phenomenon. Concerning computer resources the procedure is considerably less demanding than a direct approach with a transient model.
Backcoupling of acoustic streaming on the temperature field inside high-intensity discharge lamps
Joerg Schwieger,Bernd Baumann,Marcus Wolff,Freddy Manders,Jos Suijker
Physics , 2015, DOI: 10.1088/1742-6596/655/1/012045
Abstract: Operating high-intensity discharge lamps in the high frequency range (20-300 kHz) provides energy-saving and cost reduction potentials. However, commercially available lamp drivers do not make use of this operating strategy because light intensity fluctuations and even lamp destruction are possible. The reason for the fluctuating discharge arc are acoustic resonances in this frequency range that are excited in the arc tube. The acoustic resonances in turn generate a fluid flow that is caused by the acoustic streaming effect. Here, we present a 3D multiphysics model to determine the influence of acoustic streaming on the temperature field in the vicinity of an acoustic eigenfrequency. In that case a transition from stable to instable behavior occurs. The model is able to predict when light flicker can be expected. The results are in very good accordance with accompanying experiments.
Validation of a Questionnaire to Diagnose the Baumann Skin Type in All Ethnicities and in Various Geographic Locations  [PDF]
Leslie Baumann
Journal of Cosmetics, Dermatological Sciences and Applications (JCDSA) , 2016, DOI: 10.4236/jcdsa.2016.61005
Abstract: The Baumann Skin Typing System diagnoses patients as having one of 16 skin types based on their answers to a validated questionnaire [i] known as the Baumann Skin Type Indicator [ii]. The BSTI questionnaire has been tested over the last decade on over 200,000 people of various ages and ethnicities in different geographic locations around the world. In this study, data were collected from 52,862 patients to compare skin type prevalence between those who presented to doctor’s offices and those who took the quiz without supervision online. The most common skin types varied only slightly between patients that took the quiz online and those that completed the questionnaire in their doctor’s office. This indicates that the prevalence of skin types seen in the doctor’s office is similar to that in the general population and that supervision is not necessary to get an accurate result on the BSTI. [iii] In addition, comparison of data gathered in China, Korea, and the US did not show a significant difference in skin type prevalence between Asian and Caucasian skin types. [iv] This study demonstrates that the English version of the BSTI is valid for English speaking patients online, and in doctors’ offices in the US, China and Korea.
Nonlinear Behavior in High-Intensity Discharge Lamps
Bernd Baumann,J?rg Schwieger,Marcus Wolff,Freddy Manders,Jos Suijker
Physics , 2015,
Abstract: The light flicker problem of high intensity discharge lamps is studied numerically and experimentally. It is shown that in some respects the systems behaves very similar to the forced Duffing oscillator with a softening spring. In particular, the jump phenomenon and hysteresis are observed in the simulations and in the experiments.
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