Präoperative Diagnostik des Pankreaskarzinoms

Das präoperative Staging des Pankreaskarzinoms ist wenig normiert und oft bezüglich der Resektabilität mäßig informativ. Ziel dieser Studie ist, aus der Vielzahl der Stagingmethoden die für die Operationsplanung aussagekräftigsten herauszufinden. Es wurden hierzu 28 Patienten mit Pankreas- und Papillenkarzinom mittels MRT, 55 mittels CT, 45 mittels IDUS und 47 mittels EUS, sowie 18 Patienten mit allen vier Methoden untersucht. Die Ergebnisse der Untersuchungen wurden mit der postoperativen Histologie und dem Operationsbefund nach der TNM-Klassifikation verglichen. Die Accuracy der Beurteilung der Irresektabilität konnte durch die Kombination von CT und IDUS bzw. MRT und IDUS im Vergleich zu den Einzeluntersuchungen deutlich gesteigert werden. Eine Kombination aller Untersuchungsmethoden erbrachte unwesentlich bessere Ergebnisse bei nahezu identischen 95 %-Konfidenzintervallen und erheblichen Mehrkosten und Mehraufwand. Die Kombination einer schnittbildgebenden mit einer invasiven Methode erbringt somit eine Verbesserung der Aussagekraft des präoperativen Stagings und sollte zur Standarddiagnostik werden

Septic Arthritis Caused by Legionella dumoffii in a Patient with Systemic Lupus Erythematosus-Like Disease

We describe a patient with systemic lupus erythematosus (SLE)-like disease on immunosuppressive treatment who developed septic arthritis of the knee involving Legionella dumoffii. Cultures initially remained negative. A broad-range 16S PCR using synovial fluid revealed L. dumoffii rRNA genes, a finding that was subsequently confirmed by positive Legionella culture results

Energy spread of ultracold electron bunches extracted from a laser cooled gas

Ultrashort and ultracold electron bunches created by near-threshold femtosecond photoionization of a laser-cooled gas hold great promise for single-shot ultrafast diffraction experiments. In previous publications the transverse beam quality and the bunch length have been determined. Here the longitudinal energy spread of the generated bunches is measured for the first time, using a specially developed Wien filter. The Wien filter has been calibrated by determining the average deflection of the electron bunch as a function of magnetic field. The measured relative energy spread $\frac{\sigma_{U}}{U} = 0.64 \pm 0.09\%$ agrees well with the theoretical model which states that it is governed by the width of the ionization laser and the acceleration length

Theory and particle tracking simulations of a resonant radiofrequency deflection cavity in TM110_{110} mode for ultrafast electron microscopy

We present a theoretical description of resonant radiofrequency (RF) deflecting cavities in TM$_{110}$ mode as dynamic optical elements for ultrafast electron microscopy. We first derive the optical transfer matrix of an ideal pillbox cavity and use a Courant-Snyder formalism to calculate the 6D phase space propagation of a Gaussian electron distribution through the cavity. We derive closed, analytic expressions for the increase in transverse emittance and energy spread of the electron distribution. We demonstrate that for the special case of a beam focused in the center of the cavity, the low emittance and low energy spread of a high quality beam can be maintained, which allows high-repetition rate, ultrafast electron microscopy with 100 fs temporal resolution combined with the atomic resolution of a high-end TEM. This is confirmed by charged particle tracking simulations using a realistic cavity geometry, including fringe fields at the cavity entrance and exit apertures

Analysis of the impact of climate change on groundwater related hydrological fluxes: a multi-model approach including different downscaling methods

Climate change related modifications in the spatio-temporal distribution of precipitation and evapotranspiration will have an impact on groundwater resources. This study presents a modelling approach exploiting the advantages of integrated hydrological modelling and a broad climate model basis. We applied the integrated MIKE SHE model on a perialpine, small catchment in northern Switzerland near Zurich. To examine the impact of climate change we forced the hydrological model with data from eight GCM-RCM combinations showing systematic biases which are corrected by three different statistical downscaling methods, not only for precipitation but also for the variables that govern potential evapotranspiration. The downscaling methods are evaluated in a split sample test and the sensitivity of the downscaling procedure on the hydrological fluxes is analyzed. The RCMs resulted in very different projections of potential evapotranspiration and, especially, precipitation. All three downscaling methods reduced the differences between the predictions of the RCMs and all corrected predictions showed no future groundwater stress which can be related to an expected increase in precipitation during winter. It turned out that especially the timing of the precipitation and thus recharge is very important for the future development of the groundwater levels. However, the simulation experiments revealed the weaknesses of the downscaling methods which directly influence the predicted hydrological fluxes, and thus also the predicted groundwater levels. The downscaling process is identified as an important source of uncertainty in hydrological impact studies, which has to be accounted for. Therefore it is strongly recommended to test different downscaling methods by using verification data before applying them to climate model data

Numerical simulation of a full scale fire test on a loaded steel framework

A single bay single storey steel portal frame has been tested under fire conditions. It is here simulated using hte non linear computer code CEFICOSS. The elements have composite steel-concrete sections for the thermal analysis, but only the steel part of the sections is load bearing

A 340/380 nm light emitting diode illuminator for Fura-2 AM ratiometric Ca2+ imaging of live cells with better than 5 nM precision

We report the first demonstration of a fast wavelength-switchable 340/380 nm light emitting diode (LED) illuminator for Fura-2 ratiometric Ca2+ imaging of live cells. The LEDs closely match the excitation peaks of bound and free Fura-2 and enables the precise detection of cytosolic Ca2+ concentrations, which is only limited by the Ca2+ response of Fura-2. Using this illuminator, we have shown that Fura-2 acetoxymethyl ester (AM) concentrations as low as 250 nM can be used to detect induced Ca2+ events in tsA-201 cells and while utilizing the 150 µs switching speeds available, it was possible to image spontaneous Ca2+ transients in hippocampal neurons at a rate of 24.39 Hz that were blunted or absent at typical 0.5 Hz acquisition rates. Overall, the sensitivity and acquisition speeds available using this LED illuminator significantly improves the temporal resolution that can be obtained in comparison to current systems and supports optical imaging of fast Ca2+ events using Fura-2

Comparative study of analytical formulae for the fire resistance of steel beam-columns

peer reviewedThis paper investigates the difference between the buckling formulae published in the Eurocode 3 part 1.2 and the recommendations made in the final report of the Buckling Curves in Case of Fire (BCCF) research project. This study compares the critical temperatures obtained with both formulations to assess the impact on the fire endurance of steel columns subjected to axial compression and bending. An extensive comparison of the ultimate temperatures obtained with both formulations has been performed (382 profiles, buckling about the strong and weak axis, 12 column lengths, 6 M/N ratios and uniform and triangular bending moment distributions). Failure temperatures between 400°C and 860°C have been considered. The formulations are also compared with Finite Elements (F.E.) calculations performed for a S235 HEA 200 at 600ºC. This analysis shows that for buckling about the strong axis the BCCF method is better than the EC3 but for buckling about the weak axis the EC3 predicts failure temperatures closer to the F.E. model than the BCCF formulation. Finally, the ultimate temperatures predicted by the two formulations have also been compared with experimental results from the database SCOFIDAT. This comparison shows that there is no major difference between the two formulations for small and large bending moments. This study concludes that the EC3 and BCCF formulations are generally equivalent and that either formulation can be used

Fatigue in people with Parkinson's Disease: the effects of exercise

This thesis comprises a systematic review and an intervention study. The systematic review included a meta-analysis and investigated treatment methods for fatigue. Fourteen studies (n=1890) were included in the systematic review and results from the meta-analyses (mean difference -0.25; CI -0.67:0.16; z-score 1.20 and mean difference -0.36; CI -0.78:0.06; z-score 1.67) concluded that currently there are no effective methods for the treatment of fatigue in people with Parkinson’s disease. The intervention study (n=105; intervention group: n=54; control group: n=51) comprised three parts. In the first part different measures of fatigue were explored in relation to activity levels and exercise tolerance. The second part investigated the adherence to the community based six-month exercise programme. The final part of the main study explored the effects of the exercise programme in a single blinded randomised controlled trial. In the first part of the main study significant negative correlations were found between self-reported fatigue and respiratory exchange rate (r=-0.309; p=0.002); Rate of Perceived Exertion breath (r=-0.282; p=0.024); Rate of Perceived Exertion of the legs (r=-0.261; p=0.033) and GENEActiv light activity (r=-0.209; p=0.049). The correlation between self-reported fatigue and the respiratory exchange rate implies that self-reported fatigue may decrease if exercise tolerance is improved by for example an exercise programme. The second part of the main study demonstrated an adherence of 24 out of 54 in participants that were randomly assigned to the exercise programme, with no intervention-related adverse events, showing that the proposed programme was feasible for people with Parkinson’s disease. The final part of the study, exploring the effects of the exercise programme in all patients, showed a small reduction in disease severity (Unified Parkinson’s disease Rating Scale part III, Cohen’s d: 0.25; 95% confidence interval: 0.02-0.49) in the treatment group compared to the control group. Scores on the self-reported fatigue decreased slightly in both groups subsequent to the exercise programme, but did not reach significance. This is the first study to explore the effects of a combined (aerobic and anaerobic) exercise community based longer term (six months) exercise programme on fatigue in people with Parkinson’s disease. Results show that both arms of the interventions were adhered to reasonably well and small effects were found showing exercise improved disease severity in people with Parkinson’s disease; no effects were found in relation to fatigue

Investigation into cardiac sympathetic innervation during the commencement of haemodialysis in patients with chronic kidney disease

Background: Patients with chronic kidney disease (CKD) who undergo chronic haemodialysis (HD) show altered sympathetic tone, which is related to a higher cardiovascular mortality. The purpose of this study was to investigate the effect of transition from pre-HD to HD on cardiac sympathetic innervation. Methods: Eighteen patients aged 58 ± 18 years (mean ± standard deviation [SD]), 13 males and five females, with stage 5 CKD and nine healthy control subjects aged 52 ± 17 (mean ± SD), three males and six females, were included in this prospective study between May 2010 and December 2013. All patients underwent 123I-labelled meta-iodobenzylguanidine (123I-MIBG) scintigraphy for cardiac sympathetic innervation and electrocardiographically gated adenosine stress and rest 99mTc-labelled tetrofosmin single-photon emission computed tomography for myocardial perfusion imaging prior to (pre-HD) and 6 months after the start of HD. Results of 123I-MIBG scans in patients were compared to controls. Impaired cardiac sympathetic innervation was defined as late heart-to-mediastinum ratio (HMR) < 2.0. Results: Mean late HMR was lower in patients during HD (2.3) than in controls (2.9) (p = 0.035); however, in patients it did not differ between pre-HD and after the start of HD. During HD, two patients showed new sympathetic innervation abnormalities, and in three patients innervation abnormalities seemed to coincide with myocardial perfusion abnormalities. Conclusions: CKD patients show cardiac sympathetic innervation abnormalities, which do not seem to progress during the maintenance HD. The relationship between sympathetic innervation abnormalities and myocardial perfusion abnormalities in HD patients needs further exploration