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Bochum-Hordel, Germany

Riebe O.,HygCen Germany GmbH | Riebe O.,Universitatsstrasse 136 | Beilenhoff U.,DEGEA Deutsche Gesellschaft fur Endoskopie Assistenzpersonal E. V. | Von Rheinbaben F.,HygCen Germany GmbH | And 5 more authors.
Hygiene + Medizin

Background: The difficulty and complexity of reprocessing of flexible endoscopes have been known for more than 20 years and have been already discussed after publication of the HYGEA study in 2002. More than ten years later, we now have re-evaluated this investigation using a comparable methodology. Method: The quality of the reprocessing procedure of colonoscopes, gastroscopes and duodenoscopes was tested under routine conditions in 16 endoscopy hospital facilities as well as in seven practices. In our investigation we included different types of endoscopes from different manufacturers as well as the associated water bottle systems and the air/water and suction valves. In addition, data about the performance of the reprocessing procedure were collected using a questionnaire. Results: Of 30 biopsy channels of the endoscopes tested, eight sampled by taking swabs and seven sampled by investigating the rinse fluid (in total 13 of 30 tested endoscopes) showed bacterial contamination at low levels (< 10 Colony Forming Units (CFU) per endoscope). In addition five of 30 water samples drawn from rinsing water of the optical rinsing systems and six of 30 samples of the rinsing bottles showed weak microbial contaminations (> 1 CFU per ml or per tube). The tube of one optical rinsing system had a bacterial load of 52 CFU per ml. Although unacceptable results were not observed for the endoscopes themselves, the air/water and suction valves were often found to be microbially contaminated. Samples taken from the valves showed contamination in case of 24 air/water valves and 24 suction valves, five of them having mor e than 100 CFU per valve. Conclusion: The results presented here of the endoscope tests (reprocessing with washer-disinfectors (WD) and validated processes) and the flushing bottles of the optics tests show that lessons were learned from the HYGEA study and improvements in everyday endoscopy facilities have been achieved. However, the consistent annual average complaint rates of about 4 % as part of the quality review for colonoscopies conducted by the German Associations of Statutory Health Insurance Physicians BfArMshould prompt further efforts in endoscope reprocessing. Source

Shishkin O.V.,Ukrainian Academy of Sciences | Shishkin O.V.,University of Kharkiv | Zubatyuk R.I.,Ukrainian Academy of Sciences | Maleev A.V.,Vladimir State University | Boese R.,Universitatsstr 136
Structural Chemistry

Crystal structure of benzene-acetylene cocrystal was analysed based on calculated energies of intermolecular interactions between basic molecules located in asymmetric part of unit cell and their neighbours belonging to their first coordination sphere. It is demonstrated that the basic structural motif of the crystal is represented by infinite chains formed by the hydrogen-bonded benzene and acetylene molecules. Energy of interaction of the basic pair of molecules to neighbours within the chain is 2.2 times higher than the energy of interactions with molecules of any neighbouring chain. This ratio almost does not depend on method of calculation of interaction energy. Also, results of calculations were compared with analysis of topology of electron density distribution in crystal. The possibility to find the basic structural motif of the crystal based on properties of intermolecular bond critical points is demonstrated. © Springer Science+Business Media New York 2014. Source

Jennissen H.P.,University of Duisburg - Essen | Luers S.,Universitatsstr 136
Materialwissenschaft und Werkstofftechnik

Titanium alloys are frequently surface-modified by plasma vapor deposition of cp titanium (titanium plasma spraying, TPS; Ti-PVD surface) for clinical use. Such surfaces are extremely rough with Ra values of 30 Îm. Unmodified surfaces of Ti-PVD display apparent static contact angles of Î SâHâ2O Ë 145° which are in the ultra-/super-hydrophobic range and in agreement with contact angles of plant leaves displaying the Lotus-Effect. On the same surfaces a static contact angle of Î S Oil Ë 0° is found for mineral oil, characterizing the surface as ultra-/superlipophilic in agreement with ultrahydrophobicity (Î SâHâ2O/Î S Oil = 145°/0°). At an inclination angle of 45° droplets of water roll off the Ti-PVD surface with a running rate of Ë20 mm/s. For a classical Lotus-Effect however a roll-off angle of <10° is required. Wilhelmy plate measurements reveal an apparent dynamic advancing contact angle of Î Aâ = 98.8°, which is 46° lower than the static angle. The large contact angle hysteresis of ÎÎ â Ë 62° (Î Aâ/ Î Râ = 98.8°/36.7°) explains the high roll-off angle on Ti-PVD surfaces. The surfaces also display a type of so-called "responsive switching" between the ultrahydrophobic and ultrahydrophilic states. When they are chemically treated with chromosulfuric acid the surface becomes ultrahydrophilic (Î Aâ/ Î Râ = 0°/0°) in agreement with the inverse Lotus-Effect. Mineral oil (Î S Oil Ë 0°) and n-hexane spread completely on the ultrahydrophilic surface indicating superamphiphilicity (Î SâHâ2O/Î S Oil = 0°/0°). A switching back from the ultrahydrophilic state to the hydrophobic state occurs spontaneously if the surface is not conserved e. g. by an exsiccation layer of salt. The phenomena Lotus-Effect and inverse Lotus effect are theoretically considered. Titanlegierungen werden häufig für den Einsatz im klinischen Bereich über ein physikalisches Gasphasenabscheidungsverfahren (PVD; Titanplasmabeschichtung, TPS; Ti-PVD Oberfläche) mit cp Titan beschichtet. Solche Oberflächen sind extrem rau mit Ra-Werten von 30 Îm. Unmodifizierte Oberflächen von Ti-PVD weisen einen apparenten statischen Kontaktwinkel von Î SâHâ2O Ë 145° auf, der dem ultrahydrophoben Bereich zuzuordnen ist und im Bereich der Kontaktwinkel liegt, die Pflanzenblätter mit Lotus-Effekt kennzeichnen. Auf den gleichen Oberflächen findet man bei Messungen mit Mineralöl statische Kontaktwinkel von Î S Oil Ë 0°, die charakteristisch sind für ultra-/superlipophile Oberflächen und mit der Ultrahydrophobie übereinstimmen (Î SâHâ2O/ Î S Oil = 145°/0°). Bei einem Neigungswinkel von 45° rollen die Wassertröpfchen von der Ti-PVD Oberfläche herunter mit einer Laufgeschwindigkeit von Ë20 mm/s. Für den klassischen Lotus-Effekt sind jedoch Abrollwinkel von <10° erforderlich. Wilhelmy Plate Messungen ergeben einen apparenten dynamischen Vorrückwinkel von Î Aâ = 98.8°, der um 46° niedriger ist als der statische Winkel. Die ausgeprägte Kontaktwinkelhysterese von ÎÎ â Ë 62° (Î Aâ/ Î Râ = 98.8°/36.7°) erklärt den hohen Abrollwinkel auf Ti-PVD Oberflächen. Darüber hinaus zeigen die Ti-PVD Oberflächen eine Art von "Responsive Switching" zwischen dem ultrahydrophoben und dem ultrahydrophilen Zustand. Wenn die Oberflächen chemisch mit Chromschwefelsäure behandelt werden, wird die Oberfläche ultrahydrophil (Î Aâ/Î Râ = 0°/0°) in Übereinstimmung mit dem inversen Lotus-Effekt. Mineralöl (Î S Oil Ë 0°) und n-hexan spreiten vollständig auf der ultrahydrophilen Oberfläche, was auf Superamphiphilizität hinweist (Î SâHâ2O/ Î S Oil = 0°/0°). Ein "switching back" vom ultrahydrophilen Zustand in den hydrophoben Zustand erfolgt spontan, wenn die Oberfläche nicht z. B. durch eine Exsikkationsschicht geschützt wird. Die Phänomene Lotus-Effekt und inverser Lotus-Effekt werden theoretisch dargelegt. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Gromilov S.A.,RAS Nikolaev Institute of Inorganic Chemistry | Dyachkova T.V.,RAS Institute of Solid State Chemistry | Bykova E.A.,RAS Nikolaev Institute of Inorganic Chemistry | Tarakina N.V.,University of Wurzburg | And 2 more authors.
International Journal of Materials Research

Ir1-xRex (0.15 ≤ x ≤ 0.40) phases prepared under high-pressure, high-temperature conditions from nanopowders of iridium and rhenium were characterized using powder X-ray diffraction and scanning electron microscopy. Structural characteristics of the phases obtained were identical with the corresponding parameters for the solid solutions prepared by means of melting and thermal decomposition of the precursors. The data obtained make it possible to improve solid-state solubility limits in the binary Ir-Re phase diagram. As revealed, the maximum solid solubility of Ir in Re is 68 at.%, and that of Re in Ir is 20 at.%. © 2013 Carl Hanser Verlag GmbH &Co. KG. Source

Kupka A.,Ruhr University Bochum | Vasylyeva V.,Ruhr University Bochum | Hofmann D.W.M.,CRS4 | Yusenko K.V.,Universitatsstr 136 | Merz K.,Ruhr University Bochum
Crystal Growth and Design

The influence of pure solvents (p.a.) and impure solvents (techn. quality) on the crystallization of polymorphic forms of non-, partial-, and per-deuterated acridine from solution was investigated. Remarkably different crystallization behavior of acridine and deuterated acridine related to the used solvents was observed, especially shown in the case of acetone. © 2012 American Chemical Society. Source

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