Integrated optical directional coupler biosensor

We present measurements on biomolecular binding reactions, using a new type of integrated optical biosensor based on a planar directional coupler structure. The device is fabricated by Ag+-Na+ ion-exchange in glass and definition of the sensing region is achieved by use of transparent fluoropolymer isolation layers formed by thermal evaporation. The suitability of the sensor for application to the detection of environmental pollutants is considered

Summary of tank information relating salt well pumping to flammable gas safety issues

The Hanford Site has 149 single-shell tanks (SSTs) containing radioactive wastes that are complex mixes of radioactive and chemical products. Active use of these SSTs was phased out completely by November 1980, and the first step toward final disposal of the waste in the SSTs is interim stabilization, which involves removing essentially all of the drainable liquid from the tank. Stabilization can be achieved administratively, by jet pumping to remove drainable interstitial liquid, or by supernatant pumping. To date, 116 tanks have been declared interim stabilized; 44 SSTs have had drainable liquid removed by salt well jet pumping. Of the 149 SSTs, 19 are on the Flammable Gas Watch List (FGWL) because the waste in these tanks is known or suspected, in all but one case, to generate and retain mixtures of flammable gases, including; hydrogen, nitrous oxide, and ammonia. Salt well pumping to remove the drainable interstitial liquid from these SSTs is expected to cause the release of much of the retained gas, posing a number of safety concerns. The scope of this work is to collect and summarize information, primarily tank data and observations, that relate salt well pumping to flammable gas safety issues. While the waste within FGWL SSTs is suspected offering flammable gases, the effect of salt well pumping on the waste behavior is not well understood. This study is being conducted for the Westinghouse Hanford Company as part of the Flammable Gas Project at the Pacific Northwest National Laboratory (PNNL). Understanding the historical tank behavior during and following salt well pumping will help to resolve the associated safety issues

Controlling interferometric properties of nanoporous anodic aluminium oxide

A study of reflective interference spectroscopy [RIfS] properties of nanoporous anodic aluminium oxide [AAO] with the aim to develop a reliable substrate for label-free optical biosensing is presented. The influence of structural parameters of AAO including pore diameters, inter-pore distance, pore length, and surface modification by deposition of Au, Ag, Cr, Pt, Ni, and TiO2 on the RIfS signal (Fabry-Perot fringe) was explored. AAO with controlled pore dimensions was prepared by electrochemical anodization of aluminium using 0.3 M oxalic acid at different voltages (30 to 70 V) and anodization times (10 to 60 min). Results show the strong influence of pore structures and surface modifications on the interference signal and indicate the importance of optimisation of AAO pore structures for RIfS sensing. The pore length/pore diameter aspect ratio of AAO was identified as a suitable parameter to tune interferometric properties of AAO. Finally, the application of AAO with optimised pore structures for sensing of a surface binding reaction of alkanethiols (mercaptoundecanoic acid) on gold surface is demonstrated

Natural Feature Tracking Augmented Reality for On-Site Assembly Assistance Systems

We introduce a natural feature tracking approach that facilitates the tracking of rigid objects for an on-site assembly assistance system. The tracking system must track multiple circuit boards without added fiducial markers, and they are manipulated by the user. We use a common SIFT feature matching detector enhanced with a probability search. This search estimates how likely a set of query descriptors belongs to a particular object. The method was realized and tested. The results show that the probability search enhanced the identification of different circuit boards

Online-Überwachung eines Fermentationsprozesses mit Reflektometrischer Interferenzspektroskopie

Die prozessnahe online-Überwachung von biotechnologischen Prozessen gewinnt zunehmend an Bedeutung. Dabei werden von der Industrie vermehrt schnelle und genaue Analysenmethoden gefordert, um Kultivierungsbedingungen optimieren und die Fermentationsdauer reduzieren zu können. Bisher werden meist nur allgemeine Paramter wie Druck, Temperatur oder pH-Wert online verfolgt. Eine produktspezifische Analytik erfolgt größtenteils offline. D. h. die Proben werden manuell gezogen und nachfolgend in einem Labor analysiert. Eine solche Prozedur ist fast immer sehr arbeitsaufwändig und teuer. Problematisch kann auch die zeitliche Verzögerung zwischen Fermentationsprozess und Analysenergebnis sein. Insbesondere bei Batch-Fermentationen kann es bei Überproduktion zu Neben- und Abbauprodukten kommen. Wünschenswert ist deshalb eine zeitnahe, möglichst prozessintegrierte Anayltik, um gezielt den Fermentationprozess steuern zu können. In unserer Arbeitsgruppe wurde ein optischer Biosensor entwickelt, der eine produktspezifische, schnelle online-Überwachung eines Fermentationsprozesses erlaubt. Modellhaft wurde dabei die Produktion des Antibiotikums Vancomycin während einer Fermentation verfolgt. Die Wirkungsweise des Vancomycins beruht auf einer spezifischen Bindung an Mukopeptidvorstufen, die auf die Sequenz D-Alanin-D-Alanin enden. Um eine spezifische Detektion von Vancomycin zu erreichen wurden entsprechende Peptide kovalent auf ein Glasssubstrat immobilisiert und die Wechselwirkung zwischen der Oberfläche und Vancomycin mittels Reflektometrischer Interferenzspektroskopie (RIfS) verfolgt

Functional Characterization of Cultured Keratinocytes after Acute Cutaneous Burn Injury

In addition to forming the epithelial barrier against the outside environment keratinocytes are immunologically active cells. In the treatment of severely burned skin, cryoconserved keratinocyte allografts gain in importance. It has been proposed that these allografts accelerate wound healing also due to the expression of a favourable--keratinocyte-derived--cytokine and growth factor milieu. In this study the morphology and cytokine expression profile of keratinocytes from skin after acute burn injury was compared to non-burned skin. Skin samples were obtained from patients after severe burn injury and healthy controls. Cells were cultured and secretion of selected inflammatory mediators was quantified using Bioplex Immunoassays. Immunohistochemistry was performed to analyse further functional and morphologic parameters. Histology revealed increased terminal differentiation of keratinocytes (CK10, CK11) in allografts from non-burned skin compared to a higher portion of proliferative cells (CK5, vimentin) in acute burn injury. Increased levels of IL-1α, IL-2, IL-4, IL-10, IFN-γ and TNFα could be detected in culture media of burn injury skin cultures. Both culture groups contained large amounts of IL-1RA. IL-6 and GM-CSF were increased during the first 15 days of culture of burned skin compared to control skin. Levels of VEGF, FGF-basic, TGF-ß und G-CSF were high in both but not significantly different. Cryoconservation led to a diminished mediator synthesis except for higher levels of intracellular IL-1α and IL-1ß. Skin allografts from non-burned skin show a different secretion pattern of keratinocyte-derived cytokines and inflammatory mediators compared to keratinocytes after burn injury. As these secreted molecules exert auto- and paracrine effects and subsequently contribute to healing and barrier restoration after acute burn injury therapies affecting this specific cytokine/growth factor micromilieu could be beneficial in burned patients

The Conformational Equilibrium of the Neuropeptide Y2 Receptor in Bilayer Membranes

Dynamic structural transitions within the seven-transmembrane bundle represent the mechanism by which G-protein-coupled receptors convert an extracellular chemical signal into an intracellular biological function. Here, the conformational dynamics of the neuropeptide Y receptor type 2 (Y2R) during activation was investigated. The apo, full agonist-, and arrestin-bound states of Y2R were prepared by cell-free expression, functional refolding, and reconstitution into lipid membranes. To study conformational transitions between these states, all six tryptophans of Y2R were(13)C-labeled. NMR-signal assignment was achieved by dynamic-nuclear-polarization enhancement and the individual functional states of the receptor were characterized by monitoring(13)C NMR chemical shifts. Activation of Y2R is mediated by molecular switches involving the toggle switch residue Trp281(6.48)of the highly conserved SWLP motif and Trp327(7.55)adjacent to the NPxxY motif. Furthermore, a conformationally preserved "cysteine lock"-Trp116(23.50)was identified

Personal preference, experience, intuition and school of surgery dominate the use of wound drainage in dermatosurgery

Hintergrund Die Verwendung von Drainagesystemen in der Dermatochirurgie erfolgt bislang ohne evidenzbasierte Daten. Indikationen, Komplikationen und Kontraindikationen werden traditionell von Operateur zu Operateur weitergegeben, sind jedoch bisher nicht definiert. Methodik Es wurde eine internetbasierte Umfrage erstellt und unter den Mitgliedern der DGDC e. V. (Deutsche Gesellschaft für Dermatochirurgie e. V.) ausgesandt. Abgefragt wurden das allgemeine Behandlungsverhalten im deutschsprachigen Raum in Bezug auf die Anwendung der Wunddrainage nach dermatologischen Operationen sowie die Nutzungsgewohnheiten und Erfahrungen der Kollegen mit Drainage-assoziierten Komplikationen. Ergebnisse Es haben 12,73 % der angeschriebenen DGDC-Mitglieder den Fragebogen beantwortet. Drainagen werden überwiegend im klinischen Umfeld eingesetzt, es werden alle abgefragten Drainagesysteme verwendet. Ausmaß und Komplexität des Eingriffs sind die wesentlichen Kriterien bei der Indikationsstellung. Der Einsatz von Drainagen ist abhängig vom Alter des Teilnehmers und erfolgt mehrheitlich bei Patienten, bei denen Komplikationen im postoperativen Verlauf erwartet werden (Adipositas, Nikotinabusus, Diabetiker). Diskussion Zusammenfassend verwendet die Mehrzahl der Teilnehmer Wunddrainagen und dies mehrheitlich intuitiv. Einheitliche fixe evidenzbasierte Parameter rund um die Verwendung von Wunddrainagen fehlen. Bei der Beurteilung der Notwendigkeit einer Wunddrainage scheint ein individuell unterschiedlich ausgeprägtes Sicherheitsbedürfnis bei den einen und „eminenzbasiertes“ Handeln bei den anderen Dermatochirurgen eine große Rolle zu spielen.Background The use of drainage systems in dermatosurgery has so far been carried out without evidence-based data. The indications, complications and contraindications are traditionally passed on from surgeon to surgeon but have so far not been defined. Method An Internet-based survey was created and sent out to members of the German Society for Dermatosurgery (DGDC). The questions were on the general treatment approach in German language countries with reference to the use of wound drainage following dermatological operations as well as the utilization habits and experiences with drainage-associated complications. Results Of the DGDC members contacted 12.73% completed the questionnaire. Drainages were predominantly used in the clinical environment and all drainage systems in question were used. The extent and complexity of the intervention were essential criteria when evaluating the indications. The use of drainages was dependent on the age of the participant and mostly carried out in patients where complications in the postoperative course were to be expected (e.g. obesity, nicotine use, diabetes). Conclusion In summary, the majority of the participants used wound drainages and mostly intuitively. Uniform and fixed evidence-based parameters for the use of wound drainages are lacking. In the assessment of the necessity for a wound drainage, an individually expressed need of safety seems to play a large role for some dermatosurgeons and an eminence-based action for others