In-situ growth monitoring with scanning force microscopy during pulsed laser deposition

Imaging and mapping “new” land, species, organisms and processes created\ud possibilities to manipulate and control them. Microscopes enabled imaging objects\ud and processes that go beyond the human senses as vision, sense and hearing. This\ud information is required to understand physical and chemical processes such as\ud deposition and growth. Currently, there is also a clear need to monitor the\ud surface morphology during deposition. To image and map (non)conducting\ud surfaces with atomic resolution, Scanning Force Microscopy (SFM) can be used.\ud With physical vapor deposition techniques such as Pulsed Laser Deposition\ud (PLD) thin films of almost any material such as metal oxides can be deposited.\ud Finding the optimum deposition parameters, for material systems, is traditionally\ud done by trial and error. This can be a tedious and time-consuming process\ud especially when information on composition and morphology is lacking during\ud growth.\ud Diagnostic information during deposition of materials such as metal oxides is\ud up to now mostly derived from diffraction methods such as Reflection High\ud Energy Electron Diffraction (RHEED), Surface X-Ray Diffraction (SXRD) and\ud Low Energy Electron Diffraction (LEED).\ud These instruments are based on diffraction and measure the periodic\ud arrangement of the surface atoms. However, the local surface morphology such as\ud the island density, the island size distribution and island shapes can not be\ud directly measured on a microscopic scale as opposed to imaging techniques such\ud as Scanning Probe Microscopy (SPM). This instrument has a high spatial\ud resolution, but is usually not combined with deposition techniques and merely\ud used ex-situ*. This hampers quantitative studies to describe the nucleation and\ud growth because it is difficult to measure the evolution of the same microscopic\ud surface location and the surface morphology evolution could be influenced† by the\ud cooling procedure to room temperature, ambient exposure and ex-situ sample\ud preparation. This thesis describes a setup for in-situ growth monitoring with SFM\ud during Pulsed Laser Deposition (PLD)

Microsieves for the detection of circulating tumor cells in leukapheresis product in non-small cell lung cancer patients

Background: Circulating tumor cells (CTC) in non-small cell lung cancer (NSCLC) patients are a prognostic and possible therapeutic marker, but have a low frequency of appearance. Diagnostic leukapheresis (DLA) concentrates CTC and mononuclear cells from the blood. We evaluated a protocol using two VyCAP microsieves to filter DLA product of NSCLC patients and enumerate CTC, compared with CellSearch as a gold standard. Methods: DLA was performed in NSCLC patients before starting treatment. DLA product equaling 2×108 leukocytes was diluted to 9 mL with CellSearch dilution buffer in a Transfix CTC tube. Within 72 hours the sample was filtered with a 7 μm pore microsieve and subsequently over a 5μm pore microsieve. CTC were defined as nucleated cells which stained for cytokeratin, but lacked CD45 and CD16. CellSearch detected CTC in the same volume of DLA. Results: Of 29 patients a median of 1.4 mL DLA product (range, 0.5-4.1) was filtered (2% of total product) successfully in 93% and 45% of patients using 7 and 5 μm pores, respectively. Two DLA products were unevaluable for CTC detection. Clogging of the 5 μm but not 7 μm microsieves was positively correlated with fixation time (ρ=0.51, P<0.01). VyCAP detected CTC in 44% (12/27) of DLA products. Median CTC count per mL DLA was 0 [interquartile range (IQR): 0-1]. CellSearch detected CTC in 63% of DLA products (median =0.9 CTC per mL DLA, IQR: 0-2.1). CTC counts detected by CellSearch were significantly higher compared with VyCAP (P=0.05). Conclusions: VyCAP microsieves can identify CTC in DLA product, but workflows need to be optimized

High temperature surface imaging using atomic force microscopy

Atomic force microscopy (AFM) is one of the most important tools in nanotechnology and surface science. Because of recent developments, nowadays, it is also used to study dynamic processes, such as thin film growth and surface reaction mechanisms. These processes often take place at high temperature and there is a clear need to extend the current operating temperature range of AFM. This letter describes a heating stage and a modified AFM that extends the maximum operating temperature to 750°C. Atomic step resolution is obtained up to 500°C in ambient and even up to 750°C in vacuum