76 research outputs found

    X ray Fourier transform holography with beam shaping optical elements

    Get PDF
    Holography is a powerful method for achieving 3D images of objects. Extending this method to short wavelengths potentially offers significantly higher resolution than visible light holography. However, current X ray holography setups employ nanoscale pinholes to form the reference wave. This approach is relatively inefficient and limited to very small sample size. Here, we propose a new setup for X ray holography based on a binary diffractive optical element DOE , which forms at the same time the object illumination and the reference wave. This optic is located separately from the sample plane, which permits investigation of larger sample areas. Using an extended test sample, we demonstrate a resolution of 90 nm half pitch at an undulator beamline at BESSY II. The new holography setup can be directly transferred to free electron laser sources enabling time resolved nanoscale imaging for ultra fast processe

    Combining gemcitabine, oxaliplatin and capecitabine (GEMOXEL) for patients with advanced pancreatic carcinoma (APC): a phase I/II trial

    Get PDF
    Background: Gemcitabine remains the mainstay of palliative treatment of advanced pancreatic carcinoma (APC). Adding capecitabine or a platinum derivative each significantly prolonged survival in recent meta-analyses. The purpose of this study was to determine dose, safety and preliminary efficacy of a first-line regimen combining all three classes of active cytotoxic drugs in APC. Patients and methods: Chemotherapy-naive patients with locally advanced or metastatic, histologically proven adenocarcinoma of the pancreas were treated with a 21-day regimen of gemcitabine [1000 mg/m2 day (d) 1, d8], escalating doses of oxaliplatin (80-130 mg/m2 d1) and capecitabine (650-800 mg/m2 b.i.d. d1-d14). The recommended dose (RD), determined in the phase I part of the study by interpatient dose escalation in cohorts of three to six patients, was further studied in a two-stage phase II part with the primary end point of response rate by RECIST criteria. Results: Forty-five patients were treated with a total of 203 treatment cycles. Thrombocytopenia and diarrhea were the toxic effects limiting the dose to an RD of gemcitabine 1000 mg/m2 d1, d8; oxaliplatin 130 mg/m2 d1 and capecitabine 650 mg/m2 b.i.d. d1-14. Central independent radiological review showed partial remissions in 41% [95% confidence interval (CI) 26% to 56%] of patients and disease stabilization in 37% (95% CI 22% to 52%) of patients. Conclusion: This triple combination is feasible and, by far, met the predefined efficacy criteria warranting further investigation

    Influence of random zone positioning errors on the resolving power of Fresnel zone plates

    No full text
    Fresnel zone plates produced by electron beam lithography and planar etching techniques provide a resolving power of about 10 nm. An alternative zone plate fabrication approach is based on alternately coating a micro wire with two different materials. With this process, very thin zone layers with very high aspect ratios can be deposited. However, depending on the fabrication method, random zone positioning errors may introduce strong aberrations. We simulate the effect of positioning errors using different random fluctuations and study their influence on zone plate resolution. We find that random errors significantly decrease the contrast transfer of X ray microscopes. Additionally, we derive an upper bound for the mean acceptable variance of the deposition rat

    Strategien zur Angstreduktion in der Kleintierpraxis Teil 1 Stressreduzierende Methoden im Umgang mit Hund und Katze

    No full text
    Furcht und Angst sind im Zusammenhang mit dem Tierarztbesuch bei Hunden und Katzen weitverbreitet. Die wichtigsten Massnahmen für einen möglichst angst- und stressfreien Tierarztbesuch für Hunde und Katzen werden im Artikel vorgestellt. Dazu zählen die Anpassung der Infrastruktur an die Bedürfnisse der Tiere (z.B. Sichtbarrieren und erhöhte Ablageplätze für Katzenkörbe im Wartezimmer), der direkte Umgang mit den Tieren (z. B. deeskalierende Körpersprache, minimale Fixierung soweit möglich) und die Berücksichtigung des Einflusses des Tierhalters auf das Wohlbefinden der Tiere. Neben der Minimierung von aversiven Erlebnissen stellt das Schaffen von positiven Verknüpfungen mit der Praxis und dem Tierarztteam einen wichtigen Baustein zur Angstvermeidung und -reduktion bei Tieren dar. Dies kann besonders einfach durch freizügige Verwendung von hochwertigen Futterbelohnungen oder Spielzeug bewerkstelligt werden. Viele dieser Massnahmen können einfach und mit wenig Zeitaufwand umgesetzt werden und so das Wohlbefinden der Patienten und die Zufriedenheit der Kunden verbessern
    corecore