Direct detection of single molecules by optical absorption

The advent of single molecule optics has had a profound impact in fields ranging from biophysics to material science, photophysics, and quantum optics. However, all existing room-temperature single molecule methods have been based on fluorescence detection of highly efficient emitters. Here we demonstrate that standard, modulation-free measurements known from conventional absorption spectrometers can indeed detect single molecules. We report on quantitative measurements of the absorption cross section of single molecules under ambient condition even in their dark state, for example during photoblinking or strong quenching. Our work extends single-molecule microscopy and spectroscopy to a huge class of materials that absorb light but do not fluoresce efficiently.Comment: 15 pages, 4 figure

Organismische Drift von Gammarus fossarum KOCH 1835 (Amphipoda) und Baetidae (Ephemeroptera) in Bachabschnitten unterschiedlicher Prädatorenzusammensetzung

Die vorliegende Studie untersucht die Auswirkungen der Anwesenheit von Feuersalamanderlarven als Top-Prädatoren in fischfreien Bachabschnitten auf den Driftrhythmus von ausgewählten Evertebratentaxa und vergleicht diesen mit Driftrhythmen eines Bachabschnittes mit Bachforellenvorkommen. Dazu wurden in einem Flysch-Wienerwaldbach an drei Probenstellen mit räumlich und zeitlich unterschiedlichen Prädatorenzusammensetzungen die Driftrhythmen von je fünf Tagesgängen über den Zeitraum Frühjahr bis Herbst erfasst. Bei Gammarus fossarum und bei den Baetidae dominieren nächtliche Driftmaxima die erfassten Driftzyklen. Gammarus fossarum zeigt für alle drei möglichen Prädatorenzusammensetzungen (ohne vertebrate Prädatoren, mit Salamanderlarvenvorkommen, mit Fischvorkommen) sehr ähnliche Nachtdrift : Tagdrift-Verhältnisse. Auf dem Niveau der Individuengrößen zeigt sich ein Anstieg im Verhältnis Nachtdrift : Tagdrift von den kleinsten Individuen hin zu den großen Individuen, ein statistisch signifikanter Unterschied zwischen den verschiedenen Prädatorenzusammensetzungen ist allerdings nicht gegeben. Bei Baetidae konnte eine nicht signifikante Verlagerung der Driftaktivität in die Nachtstunden von Stellen ohne vertebrate Prädatoren über Salamanderlarvenvorkommen bis hin zu Fischvorkommen beobachtet werden. Auch auf Niveau der Individuengrößen zeigt sich bei Baetidae ein Anstieg des Nachtdrift : Tagdrift-Verhältnisses mit der Körpergröße, wobei dieser an dem Bachabschnitt mit Fischvorkommen am deutlichsten ausfällt. Der vorliegende Driftrhythmus von Gammarus fossarum kann somit als fixiertes Verhaltensmuster angenommen werden, das unabhängig von der An- bzw. Abwesenheit von vertebraten Prädatoren stattfindet. Ein zu erwartender aperiodischer Driftzyklus der Baetidae in Bachabschnitten ohne vertebrate Prädatoren konnte nicht nachgewiesen werden. Gemeinsam mit der Annahme eines Verbleibens von Salamanderlarven im Bach oder der Annahme des Beibehaltens eines etablierten Driftrhythmus, sowie eines Anstieges des Nachdrift : Tagdrift-Verhältnis von fischfreien Bachabschnitten gegenüber Bachabschnitten mit Salamanderlarvenvorkommen, zeigt sich eine – wenn auch geringe – Auswirkung von Feuersalamanderlarven auf das Driftverhalten der Baetidae.The study investigates the effect of larval firesalamanders as top predators in fishless stream reaches on the drift frequency of selected invertebrate taxa and compares this effect with stream reaches where brown trout is present. Five diurnal drift cycles were collected on three sampling stations with different temporal and spatial predator compositions over a period from spring to autumn in a forest stream of the Wienerwald. The collected drift frequencies of Gammarus fossarum and Baetidae are dominated by nocturnal drift maxima. For all possible predator combinations (without vertebrate predators, with fire salamander occurence, with fish occurence) nightdrift : daydrift ratios were not significant in Gammarus fossarum. In Baetis, however, the nightdrift : daydrift ratio showed an increase from the smallest to the larger nymphs with no significant differences between the different predator compositions. A non-significant shift of drift activity of Baetidae towards nighttime is detected, increasing from stream reaches without vertebrate predators over stream reaches with larval fire salamanders to stream reaches with fish occurence. An increase of nightdrift : daydrift ratios at the level of individual size classes of Baetidae is correlated with an increase in body size, which is most apparent in stream reaches with fish occurence. The observed drift patterns of Gammarus fossarum is thought to be a fixed behavioural pattern that is insensitive to the presence or absence of vertebrate predators. The expected aperiodic drift cycle of Baetidae in stream reaches without predators could not be observed. Overwintering larval fire salamanders in the stream and/or the maintenance of an established drift periodicity as well as the observation of increasing nightdrift : daydrift ratios which increase from stream reaches without vertebrate predators to stream reaches with larval fire salamanders demonstrate a weak impact of larval fire salamanders on the drift behaviour of Baetidae

Percutaneous Cannulation for Extracorporeal Life Support in Severely and Morbidly Obese Patients

Background: Extracorporeal life support systems are well-established devices for treating patients with acute cardiopulmonary failure. Severe or morbid obesity may result in complications such as limb ischemia, bleeding, unsuccessful cannulation, or infection at the cannulation sites. This article reports on our experience with cannulation and associated complications in severely and morbidly obese patients. Methods: Between January 2006 and September 2016, 153 severely or morbidly obese patients with a body mass index >35 kg/m(2)were cannulated percutaneously for extracorporeal life support at our center. Among those, 115 patients were treated with venovenous extracorporeal membrane oxygenation (VV ECMO) for acute lung failure and 38 patients with venoarterial extracorporeal membrane oxygenation (VA ECMO) for cardiogenic shock. Complications related to percutaneous access and long-term follow-up were analyzed retrospectively. Primary focus was on the success of cannulation, outcome, thrombosis, bleeding, limb ischemia, and infection at the cannulation site. Normal-weight patients receiving extracorporeal life support served as control. Results: Percutaneous cannulation was successfully performed in all patients. Eighty-five (74%) patients were weaned from VV ECMO and 20 (52%) patients were weaned from VA ECMO. Limb ischemia requiring surgical intervention occurred in 5 (3%) patients, bleeding in 7 (5%) patients, and wound infection in 3 (2%) patients. In all other patients, decannulation was uneventful. These data as well as the long-term survival rates were comparable to those of normal-weight patients (P> .05). Conclusion: Percutaneous vessel cannulation for extracorporeal life support systems is generally feasible. Therefore, percutaneous cannulation may well be performed in severely and morbidly obese patients. Patient outcome rather depends on appropriate support than on anatomy

Studies in Health Technology and Informatics

Background: Standards have become available to share semantically encoded vital parameters from medical devices, as required for example by personal healthcare records. Standardised sharing of biosignal data largely remains open. Objectives: The goal of this work is to explore available biosignal file format and data exchange standards and profiles, and to conceptualise end-To-end solutions. Methods: The authors reviewed and discussed available biosignal file format standards with other members of international standards development organisations (SDOs). Results: A raw concept for standards based acquisition, storage, archiving and sharing of biosignals was developed. The GDF format may serve for storing biosignals. Signals can then be shared using FHIR resources and may be stored on FHIR servers or in DICOM archives, with DICOM waveforms as one possible format. Conclusion: Currently a group of international SDOs (e.g. HL7, IHE, DICOM, IEEE) is engaged in intensive discussions. This discussion extends existing work that already was adopted by large implementer communities. The concept presented here only reports the current status of the discussion in Austria. The discussion will continue internationally, with results to be expected over the coming years

Reliability of different body temperature measurement sites during aortic surgery

Objective: We retrospectively performed a comparative analysis of temperature measurement sites during surgical repair of the thoracic aorta. Methods: Between January 2004 and May 2006, 22 patients (mean age: 63±12 years) underwent operations on the thoracic aorta with arterial cannulation of the aortic arch concavity and selective antegrade cerebral perfusion (ACP) during deep hypothermic circulatory arrest (HCA). Indications for surgical intervention were acute type A dissection in 14 (64%) patients, degenerative aneurysm in 6 (27%), aortic infiltration of thymic carcinoma in 1 (4.5%) and intra-aortic stent refixation in 1 (4.5%). Rectal, tympanic and bladder temperatures were evaluated to identify the best reference to arterial blood temperature during HCA and ACP. Results: There were no operative deaths and the 30-day mortality rate was 13% (three patients). Permanent neurological deficits were not observed and transient changes occurred in two patients (9%). During re-warming, there was strong correlation between tympanic and arterial blood temperatures (r= 0.9541, p<0.001), in contrast to the rectal and bladder temperature (r=0.7654, p= n.s; r=0.7939, p= n.s., respectively). Conclusion: We conclude that tympanic temperature measurements correlate with arterial blood temperature monitoring during aortic surgery with HCA and ACP and, therefore, should replace bladder and rectal measurements

Minimized extracorporeal circulation is improving outcome of coronary artery bypass surgery in the elderly

Advanced age is a known risk factor for morbidity and mortality after coronary artery bypass grafting (CABG). Minimized extracorporeal circulation (MECC) has been shown to reduce the negative effects associated with conventional extracorporeal circulation (CECC). This trial assesses the impact of MECC on the outcome of elderly patients undergoing CABG. Eight hundred and seventy-five patients (mean age 78.35 years) underwent isolated CABG using CECC (n=345) or MECC (n=530). The MECC group had a significantly shorter extracorporeal circulation time (ECCT), cross-clamp time and reperfusion time and lower transfusion needs. Postoperatively, these patients required significantly less inotropic support, fewer blood transfusions, less postoperative hemodialysis and developed less delirium compared to CECC patients. In the MECC group, intensive care unit (ICU) stay was significantly shorter and 30-day mortality was significantly reduced [2.6% versus 7.8%; p<0.001]. In conclusion, MECC improves outcome in elderly patients undergoing CABG surgery

The influence of process parameters on the temperature development in the forming zone

Cold metal forming is a fast and economical way of producing a wide range of precise components. Its profitability mainly depends on part quality, process stability and service intervals of tools. As these factors are all determined by tool wear, detailed process knowledge is indispensable to maximize profitability by minimizing wear. One of the most crucial factors in this context is temperature. During every forming process, a temperature rise occurs between tool and workpiece due to frictional heating and a large part of plastic work dissipating into heat. This temperature affects the whole forming process but especially tool wear. Currently, there is little solid information about temperatures occurring during forming operations. Therefore, the temperature was measured based on varying process parameters in several embossing and blanking examinations. The use of a tool-workpiece-thermocouple enabled accurate and instantaneous measurement during the process. The results presented show the strong influence of process parameters on temperatures in the forming zone