Optical reconstruction of high-speed surface dynamics in an uncontrollable environment

The ability to communicate with our voice can be regarded as the concatenation of the two processes "phonation" and "modulation." These take place in the larynx and palatal and oral region, respectively. During phonation the audible primary voice signal is created by mutual reaction of vocal folds with the exhaled air stream of the lungs. The underlying interactions of masses, fluids and acoustics have yet to be identified and understood. One part of the primary signal's acoustical source are vortex induced vibrations, as e.g., created by the Coand?effect in the air stream. The development of these vorteces is determined by the shape and 3-D movements of the vocal folds in the larynx. Current clinical in vivo research methods for vocal folds do not deliver data of satisfactory quality for fundamental research, e.g., an endoscope is limited to 2-D image information. Based hereupon, a few improved methods have been presented, however delivering only selective 3-D information, either for a single point or a line. This stands in contrast to the 3-D motions of the entire vocal fold surface. More complex imaging methods, such as MRI, do not deliver information in real-time. Thus, it is necessary to develop an easily applicable, more improved examination method, which allows for 3-D data of the vocal folds surfaces to be obtained. We present a method to calibrate a 3-D reconstruction setup including a laser projection system and a high-speed camera. The setup is designed with miniaturization and an in vivo application in mind. The laser projection system generates a divergent grid of 196 laser dots by diffraction gratings. It is calibrated with a planar calibration target through planar homography. In general, the setup allows to reconstruct the topology of a surface at high frame rates (up to 4000 frames per second) and in uncontrollable environments, as e.g., given by the lighting situation (little to no ambient light) and varying texture (e.g., varying grade of reflection) in the human larynx. In particular, this system measures the 3-D vocal fold surface dynamics during phonation. Applied to synthetic data, the calibration is shown to be robust (error approximately 0.5 μm) regarding noise and systematic errors. Experimental data gained with a linear z -stage proved that the system reconstructs the 3-D coordinates of points with an error at approximately 15 μm. The method was applied exemplarily to reconstruct porcine and artificial vocal folds' surfaces during phonation. Local differences such as asymmetry between left and right fold dynamics, as well as global parameters, such as opening and closing speed and maximum displacements, were identified and quantified.     

Catalytically Doped Semiconductors for Chemical Gas Sensing: Aerogel‐Like Aluminum‐Containing Zinc Oxide Materials Prepared in the Gas Phase

Atmospheric contamination with organic compounds is undesired in industry and in society because of odor nuisance or potential toxicity. Resistive gas sensors made of semiconducting metal oxides are effective in the detection of gases even at low concentration. Major drawbacks are low selectivity and missing sensitivity toward a targeted compound. Acetaldehyde is selected due to its high relevance in chemical industry and its toxic character. Considering the similarity between gas‐sensing and heterogeneous catalysis (surface reactions, activity, selectivity), it is tempting to transfer concepts. A question of importance is how doping and the resulting change in electronic properties of a metal‐oxide support with semiconducting properties alters reactivity of the surfaces and the functionality in gas‐sensing and in heterogeneous catalysis. A gas‐phase synthesis method is employed for aerogel‐like zinc oxide materials with a defined content of aluminum (n‐doping), which were then used for the assembly of gas sensors. It is shown that only Al‐doped ZnO represents an effective sensor material that is sensitive down to very low concentrations (<350 ppb). The advance in properties relates to a catalytic effect for the doped semiconductor nanomaterial.     

Full CMOS continuous time filters for GSM applications

This paper describes full cmoscontinuous time filter design techniques which can meet the specifications commonly set for gsmapplications. First several cmosfilter design techniques are overviewed. The ota-ctechnique is discussed to some more detail. To overcome the main drawback of the lower total harmonic distortion in ota-ctechniques very linear operational transconductance amplifiers (ota)are required. Such an ota,together with the applied linearisation techniques is discussed. To fulfil high accuracy in cut- off frequencies of the filter an active tuning system is necessary. A new on- chip tuning system is presented. The paper concludes with a practical design example for the gsmsystem. Therein the different ota-ctechniques discussed are illustrated.     

Hydrogen energy from coupled waste gasification and cement production—a thermochemical concept study

A plant concept for hydrogen production from waste gasification coupled with cement manufacturing is presented. Hot precalcined cement meal, from the operating cement process, is used as heat carrier to provide energy required by the parallel arranged gasifier. The amount of CaO present in the cement meal operates simultaneously as an effective in situ _CO2${\mathrm{CO}}_2$-sorbent. First, a practical case study was devised to be able to perform simulations for estimation of expected hydrogen yield. The influence of different operation parameters of the gasifier and the hydrogen separation unit (steam-to-fuel ratio, pyrolysis temperature, PSA efficiency) was studied based on chemical equilibrium calculations. The simulation results indicate, that the coupling provides advantages for both processes. The production of a hydrogen-rich gas via thermal gasification benefits from the continuously available fresh CaO, which improves fuel conversion reactions and captures _CO2${\mathrm{CO}}_2$ in situ. High-calorific streams from gasification process remaining after hydrogen separation may substitute fossil fuels needed for cement process. For a steam/fuel ratio of 0.3 and a PSA efficiency of 0.7, the calculated hydrogen energy yield is 46% of fuel energy input.     

Lebensmittelkontaminationen im Emissionsbereich Chemischer Reinigungen

Zusammenfassung Lebensmittel, die im Emissionsbereich Chemischer Reinigungen gelagert bzw. verkauft werden, können erheblich mit Tetrachlorethen belastet sein. Hohe Tetrachlorethengehalte wurden sowohl in Lebensmittelproben aus über Chemischen Reinigungen gelegenen Wohnungen als auch in Proben aus dem Lebensmitteleinzelhandel festgestellt. Lebensmittel mit hohem Fettgehalt wiesen stets die höchsten Kontaminationen auf.

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Contamination of foodstuffs by emissions from dry cleaning units

Summary Tetrachloroethene (perchloroethylene) from dry-cleaning units may contaminate adjacent flats in the same building. Increased concentrations of tetrachloroethene have been found in foodstuffs in homes situated above dry cleaning units and in foodstuffs from groceries located neat drycleaning units. The concentrations were extremely high in foods rich in fat.

     

Living cationic polymerization of isobutyl vinyl ether, 2

Summary Living cationic polymerization of isobutul vinyl ether (IBVE), initiated by1-iodo-1-(2-methyl propyloxy)-ethane (1) and tetraalkylammonium perchlorate yields polymers of well defined molar masses and end groups. The controlled introduction of end groups was confirmed by a model reaction and was then applied to introduce and azo initiator function. The resulting polymeric initiator was used for the synthesis of a blockcopolymer.     

Male pheromone of swift moth,Hepialus hecta L. (Lepidoptera: Hepialidae)

(R)-6-Ethyl-2-methyl-2,3-dihydro-4H-pyran-4-one, (1R,3S,5R)-3-ethyl-1,8-dimethyl-2,9-dioxabicyclo[3.3. 1]non-7-ene, and (1R,3S,5R)-3-ethyl-1,8-dimethyl-2,9-dioxabicyclo[3.3.1]non-7-en-6-one represent the main components in the male pheromone of the swift moth,Hepialus hecta. The amounts of the three components were 40, 5, and 5 g per male, respectively. Structure elucidation of the compounds was based on spectroscopic data as compared to synthetic reference samples. The absolute configurations were determined by gas chromatography on chiral stationary phases; optically active samples served as reference compounds. Electrophysiological and behavioral experiments with natural material and synthetic samples clearly showed the three heterocyclic compounds to act as pheromones. (E, E)--Farnesene represents the main component of the scent secretion of maleHepialus humuli.     

Relation between the structure of matrices and their mechanical relaxation mechanisms during the glass transition of biomaterials: A review

It has been demonstrated that industrial polysaccharides (agarose, deacylated gellan and κ-carrageenan) form networks of reduced enthalpic content in the presence of high levels of non-crystallizing co-solute (e.g., glucose syrup) that exhibit time-temperature dependent behaviour of a typical rubberlike polymer. In contrast, amylose holds its structural characteristics unaltered and does not reach a state of molecular mixing with glucose syrup, with morphological features being those of a micro phase-separated mixture. Variation in phase morphology and density of intermolecular associations leads to entropic or enthalpic viscoelasticity in systems, and it was utilised to define distinct classes of food related biomaterials exhibiting an extensive glass transition region or absence of vitrification phenomena. The approach was extended to encompass the experimental parameters of a porous matrix and the application of hydrostatic pressure. In the former, work discusses discrepancies in the T_g - porosity relationship attributable to the different extent to which the two techniques of calorimetry and mechanical spectroscopy respond to degrees of molecular mobility. In the latter, it was shown that the time-temperature-pressure equivalence of synthetic amorphous polymers is not operational in the glass-like behaviour of high sugar systems in the presence of gelatin or gelling polysaccharides. The existing body of evidence allowed quantitative treatment of results based on the asymmetric distribution theory of molecular relaxation time that identifies the chemical fingerprint of the local motions operating at the vicinity of T_g. Furthermore, the diffusional mobility of a bioactive compound within a glassy matrix could be followed in relation to temperature induced changes in free volume using the time-temperature superposition principle.     

Bioavailability of nutraceuticals: Role of the food matrix,processing conditions,the gastrointestinal tract,and nanodelivery systems

Nowadays, many consumers prefer foods with a high content of nutraceuticals that contribute to the prevention or healing of chronic diseases. Therefore, in recent years, more and more researchers have studied the bioefficiency, safety, and toxicity of nutraceutical‐enriched foods. The key stage of nutraceutical bioefficiency is oral bioavailability, which involves the following processes: the release of nutraceuticals from food matrices or nanocarriers in gastrointestinal fluids, the solubilization of nutraceuticals and their interaction with other components of gastrointestinal fluids, the absorption of nutraceuticals by the epithelial layer, and the chemical and biochemical transformations into epithelial cells. These processes are endogenous factors that greatly influence the bioavailability of nutraceuticals. In addition to endogenous factors, the bioavailability of nutraceuticals is also affected by exogenous factors, such as: physicochemical properties of nutraceuticals, food matrix, food processing and storage, and so forth. Both the endogenous and exogenous factors are comprehensively analyzed in this review. Thus, the physicochemical and enzymatic processes involved in food digestion are described, highlighting the role of each stage of gastrointestinal tract (mouth, stomach, and intestine) in nutraceuticals bioaccessibility. The structure and functions of the mucus and epithelial layers, the mechanisms involved in the active and passive transport of nutraceuticals through the cell membrane, and phase I and phase II metabolism reactions are also discussed. Finally, this review focuses on several types of bioactive‐loaded nanocarriers such as lipid‐based, surfactant‐based, and biopolymeric nanocarriers that improve the bioavailability of nutraceuticals.