Cellulose‐Based Ionogels for Paper Electronics

A new class of biofriendly ionogels produced by gelation of microcellulose thin films with tailored 1‐ethyl‐3‐methylimidazolium methylphosphonate ionic liquids are demonstrated. The cellulose ionogels show promising properties for application in flexible electronics, such as transparency, flexibility, transferability, and high specific capacitances of 5 to 15 μF cm^?2. They can be laminated onto any substrate such as multilayer‐coated paper and act as high capacitance dielectrics for inorganic (spray‐coated ZnO and colloidal ZnO nanorods) and organic (poly[3‐hexylthiophene], P3HT) electrolyte‐gated field‐effect transistors (FETs), that operate at very low voltages (<2 V). Field‐effect mobilities in ionogel‐gated spray‐coated ZnO FETs reach 75 cm² V^?1 s^?1 and a typical increase of mobility with decreasing specific capacitance of the ionogel is observed. Solution‐processed, colloidal ZnO nanorods and laminated cellulose ionogels enable the fabrication of the first electrolyte‐gated, flexible circuits on paper, which operate at bending radii down to 1.1 mm.     

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.     

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.     

Moderne Massenspektrometer in Vakuum‐Applikationen

Modern mass spectrometers in vacuum applications The article describes the functionality of quadrupole mass spectrometers and their usage in different applications. Several examples illustrate the importance of careful interpretation of the respective spectra. Some applications allow the direct installation into a vacuum chamber while other applications require an external pump system which is only weakly connected to the vacuum chamber.     

Relations between in-treatment and follow-up abstinence among cocaine-dependent homeless persons in three clinical trials.

Clinical trials with cocaine-dependent outpatients have found a strong relation between in-treatment and follow-up abstinence, and the strength of this relation is constant across treatment conditions with variable efficacy in generating abstinence. The authors conducted secondary analyses of data from 3 clinical trials to determine whether this relation generalizes to cocaine-dependent homeless persons. The 3 trials (total N = 543) were conducted in a community health care facility for homeless people. The 7 treatment arms across the 3 trials were combinations of day treatment, abstinence-contingent housing, and vocational training. Drug use was measured with urine toxicology testing. Consecutive weeks of abstinence during treatment were strongly related to abstinence at the 12-month follow-up, whether or not missing 12-month data were included in the analysis. The treatment arms differed in their efficacy in generating abstinence, but the relation between in-treatment and follow-up abstinence did not differ across treatment arms. These results replicate earlier reports of these relations and extend them to a population of homeless people. The lack of differences between treatment arms in the in-treatment–follow-up abstinence relation implies that that relation is independent of the treatment-specific intervention components that generate group differences in abstinence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Functionalized galactoglucomannan‐based hydrogels for the removal of metal cations from aqueous solutions

New types of hydrogels derived from O‐acetyl galactoglucomannan (AcGGM) hemicellulose have been synthesized and characterized. The objective of this work was to analyze the sorption capacity (S) of three types of hydrogels containing AcGGM derivatives incorporated into the carboxylic groups of the polymer chain in the AA hydrogel, sulfonic groups in the APA hydrogel, and amide groups in the acrylamide (Aam) hydrogel. These hydrogels are capable of interacting and removing ions such as cadmium [Cd(II)], copper [Cu(II)], lead [Pb(II)], nickel [Ni(II)], and zinc [Zn(II)]. The results show that AA and Aam hydrogels had a lower sorption capacity of ions compared to the APA hydrogel, which had a high sorption capacity. The maximal sorption capacity was determined by the successive enrichment method, obtaining Pb(II) amount of 48.3 mg/g of AA hydrogel, 65.8 mg/g of APA hydrogel, and 40.8 mg/g of Aam hydrogel. Hence, Pb(II) ions are greatly retained by the three hydrogels. These results are promising for the development of new materials with potential applications in metal ion removal. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44093.     

An Efficient New Pyrimidine Synthesis – a pathway to octupoles

The condensation of N,N,N′-tris(trimethylsilyl)-amidines ( 6 , 11 , 22 ) with vinamidinium salts ( 1 , 7 ) in the presence of potassium fluoride is the method of choice for the synthesis of pyrimidines ( 8 , 12 , 20 , 23 ). Octupoles comprising 1,3,5-benzene ( 8 ) and triphenylamine ( 12 , 20 ) derivatives can be prepared in high yields.