A high-gain Quantum free-electron laser: emergence & exponential gain

We derive an effective Dicke model in momentum space to describe collective effects in the quantum regime of a free-electron laser (FEL). The resulting exponential gain from a single passage of electrons allows the operation of a Quantum FEL in the high-gain mode and avoids the experimental challenges of an X-ray FEL oscillator. Moreover, we study the intensity fluctuations of the emitted radiation which turn out to be super-Poissonian

The Beam Conditions Monitor of the LHCb Experiment

The LHCb experiment at the European Organization for Nuclear Research (CERN) is dedicated to precision measurements of CP violation and rare decays of B hadrons. Its most sensitive components are protected by means of a Beam Conditions Monitor (BCM), based on polycrystalline CVD diamond sensors. Its configuration, operation and decision logics to issue or remove the beam permit signal for the Large Hadron Collider (LHC) are described in this paper.Comment: Index Terms: Accelerator measurement systems, CVD, Diamond, Radiation detector

Remote Assessment of Cultural Heritage Environments with Wireless Sensor Array Networks

The logistics and cost of environmental monitoring can represent challenges for heritage managers, partly because of the sheer number of environmental parameters to consider. There is a need for a system, capable of monitoring the holistic impact of the environment on cultural materials while remaining relatively easy to use and providing remote access. This paper describes a dosimetric system based on piezoelectric quartz crystal technology. The prototype sensing module consists of an array of piezoelectric quartz crystals (PQC) coated with different metals (Fe, Cu, Ni and Sn) and includes a temperature and relative humidity sensor. The communication module involves an 802.15.4 low-power radio and a GPRS gateway which allows real time visualisation of the measurements online. An energy management protocol ensures that the system consumes very low power between measurements. The paper also describes the results and experiences from two heritage field deployments, at Apsley House in London, UK, and at the Royal Palaces of Abomey in Benin. Evaluation of PQC measurements, temperature, relative humidity and the rate of successful transmission over the communication systems are also reported

Illness behaviour and influencing aspects of general practitioners in Germany and their use of the health care system: a qualitative study

Objectives The aim of this study was to explore aspects that play a role when general practitioners (GPs) become ill and thus gain a more comprehensive understanding of the overall illness behaviour of GPs and their use of the healthcare system. Setting Primary care practices in Thuringia, Germany. Participants Convenience sample of 16 GPs. Design Qualitative study design with semistructured interviews and content analysis. Results Using our approach of having participants report their own episodes of illness, we found that self-treatment was practised and accepted by all 16 participants. The widespread use of naturopathy and complementary methods seems to be a special feature of German GPs. Formal use of the healthcare system mainly took place through direct consultation with specialists. Our study revealed various aspects influencing the illness behaviour of the GPs and their use of the healthcare system. Some aspects also apply to lay patients, but it became clear how strongly illness behaviour is influenced by participants’ activities as physicians. Noteworthy and less described aspects are especially the influence of patients and practice staff, the influence of biographical and professional imprint and the attitudes and values of the physicians. Complex inter-relationships were found between illness behaviour and influencing aspects; these are subjected to a dynamic and recursive process. Conclusions The illness behaviour of German GPs seems to be comprehensively influenced by their activities as responsible healthcare providers. The ability to perceive and reflect in this regards should already be actively promoted in studies and further education. Further research is needed for a better understanding of the inter-relationships

A quartz crystal biosensor for measurement in liquids

The detection of anti-human immunodeficiency virus (HIV) antibodies by means of synthetic HIV peptide immobilized on a piezoelectric quartz sensor is demonstrated. The measurement set-up consists of an oscillator circuit, a suitably modified AT-cut thickness-shear-mode quartz crystal with gold electrodes, which is housed in a special reaction vessel, and a computer-controlled frequency counter for the registration of the measured frequency values. The quartz crystal is adapted for a steady operation in liquids at a frequency of 20 MHz. In phosphate-buffered saline solution the oscillator reaches a stability of about 0.5 Hz within a few seconds, of about 2 Hz within 10 min and about 30 Hz within 1 h. The frequency shift due to the adsorption of various proteins to the uncoated sensor surface has been investigated. It can be shown that a stable adsorptive binding of proteins to an oscillating gold surface is feasible and can be used for the immobilization of a receptor layer (e.g. HIV peptide). Specific binding of the anti-HIV monoclonal antibody to the HIV peptide immobilized on the quartz sensor is demonstrated. Control experiments show, however, additional unspecific binding. According to the experiments, the Sauerbrey formula gives a sufficiently accurate value for the decrease of the resonant frequency due to adsorption or binding of macromolecular proteins on the quartz crystal surface

ST Quartz Acoustic Wave Sensors with Sectional Guiding Layers

We report the effect of removing a section of guiding layer from the propagation paths of ST-quartz Love wave sensors; this offers the ease of fabrication of a polymer guiding layer whilst retaining the native surface of the quartz which may then be used for the attachment of a sensitizing layer. Data is presented for rigid and viscous loading, which indicates a small reduction in mass sensitivity compared to a Love wave device. Biosensing capabilities of these discontinuous ‘sectional’ guiding layer devices are demonstrated using protein adsorption from solution

Design and evaluation of a 3D printed multi vessel model for particle embolization training

Einleitung: Die Ausbildung von Assistenzärzten in der interventionellen Radiologie erfolgt aktuell hauptsächlich mit dem „master-apprentice system“. Dabei werden erste praktische Erfahrungen meist direkt am Patienten erworben. Gerade bei komplexen Prozeduren, wie z.B. der Embolisation mit Partikeln, kann dies unter Umständen mit einem erhöhten Risiko für den Patienten einhergehen. Im Rahmen dieser Arbeit wurde daher ein Trainingsmodell entwickelt, mit dem Partikelembolisationen simuliert und trainiert werden können. Methodik: In Experteninterviews mit erfahrenen interventionellen Radiologen zu den möglichen Anforderungen an ein Trainingsmodell wurden Modellanforderungen und Lernziele festgelegt. In einem zweiten Schritt wurde ein physisches Modell mit Hilfe von CAD Software entwickelt, entworfen und mittels 3D-Drucker gedruckt. In Rücksprache mit erfahrenen Interventionalisten wurde über mehrere Iterationen hinweg ein funktionsfähiges Modell entworfen, mit dem Partikelembolisationen zuverlässig trainiert werden können. Dieses Modell wurde durch eine Gruppe von Experten (n = 6) getestet und anhand eines Fragebogens evaluiert. Zusätzlich fand eine Bewertung durch Studierende (n = 10) ohne Erfahrung mit Partikelembolisationen im Rahmen eines Trainings statt. Ergebnisse: Das finale Modell erfüllt alle im Expertengespräch definierten Modellanforderungen. Die Evaluation durch die Expertengruppe deutet darauf hin, dass alle definierten Lernziele durch ein Training mit dem erstellten Modell erreicht werden können. Der Einschätzung der Experten zufolge ist das Modell gut geeignet, um wichtige Teilschritte, sowie Komplikationen einer Partikelembolisation zu vermitteln. Das Modell kann aus Expertensicht daher sehr gut in der Ausbildung eingesetzt werden. Dies konnte im Training mit den Studierenden erfolgreich bestätigt werden, da diese sich nach bereits einem Training mit dem Modell in fünf Punkten signifikant verbessert haben. Diskussion: Das Trainingsmodell ist laut Expertenevaluation und bestätigendem Training mit Studierenden dazu in der Lage, die Grundlagen der Partikelembolisation erfolgreich zu vermitteln. Ein Training mit dem Modell ist kostengünstig und zeiteffizient, da es unabhängig von Patientenverfügbarkeit jederzeit ausgeführt werden kann. Ein breiter Einsatz in der Ausbildung von Assistenzärzten der interventionellen Radiologie könnte den Ausbildungsstandard erhöhen, die Ausbildung homogener gestalten und letztlich auch die Patientensicherheit erhöhen.Background: The training of residents in the field of interventional radiology mainly relies on the „master-apprentice system“. The first practical operations of residents are mostly carried out on patients themselves. Complex tasks especially, like particle embolization procedures, bear a risk for the patient’s safety. For this study, a physical training model was developed which is capable of simulating particle embolization and meant for training of particle embolization procedures. Methods: Model requirements as well as learning objectives for an efficient training were identified in an interview with interventional radiology experts. A first model was then designed and developed using CAD software and finally printed using a 3D-printer. With the feedback of the experts, the model was refined over several iterations until a fully functional model, capable of simulating particle embolization, could be printed. This final model was evaluated by a group of experts (n = 6) by training and through a questionnaire. Additionally, a group of medical students (n = 10) without any experience in the field of particle embolization evaluated the model in a training program. Results: The final model fulfils all defined model requirements. The evaluation through the expert group indicates that all learning objectives can be reached by training with the model. Subjectively, the experts think the model is well suited to be used in the residency program of interventional radiologists, teaching important steps of particle embolization as well as complications. These observations were proven by the training program with the medical students as they significantly increased their subjective score. Conclusion: According to the experts of interventional radiology, the model is capable to teach the basics of catheter handling as well as particle embolization. Training with the model is time and cost efficient, as it does not depend on patient availability or consent. It can be performed independently at any time. A broad availability of the model in interventional radiology residency programs could possibly increase the standards of the program, homogenise the training and ultimately increase patient safety. These possible advantages of the use of our model should be subject of further studies