33 research outputs found
Mutual Unbiasedness in Coarse-grained Continuous Variables
The notion of mutual unbiasedness for coarse-grained measurements of quantum
continuous variable systems is considered. It is shown that while the procedure
of "standard" coarse graining breaks the mutual unbiasedness between conjugate
variables, this desired feature can be theoretically established and
experimentally observed in periodic coarse graining. We illustrate our results
in an optics experiment implementing Fraunhofer diffraction through a periodic
diffraction grating, finding excellent agreement with the derived theory. Our
results are an important step in developing a formal connection between
discrete and continuous variable quantum mechanics.Comment: 5 pages, 3 figures + Supplemental Material (1 page) v2: Introduction
expanded, minor typos correcte
Feasibility of simultaneous PET/MR imaging in the head and upper neck area
Objective: The aim of this pilot study was to test and demonstrate the feasibility of simultaneous positron emission tomography (PET) and magnetic resonance imaging (MRI) of the head and upper neck area using a new hybrid PET/MRI system. Methods: Eight patients with malignant head and neck tumours were included in the pilot study. Directly after routine PET/CT imaging with a whole-body system using the glucose derivative 2-[18F]fluoro-2deoxy-D-glucose (FDG) as a radiotracer additional measurements were performed with a prototype PET/MRI system for simultaneous PET and MR imaging. Physiological radiotracer uptake within regular anatomical structures as well as tumour uptake were evaluated visually and semiquantitatively (metabolic ratios) in relation to cerebellar uptake on the PET/MRI and PET/CT systems. Results: The MR datasets showed excellent image quality without any recognisable artefacts caused by the inserted PET system. PET images obtained with the PET/MRI system exhibited better detailed resolution and greater image contrast in comparison to those from the PET/CT system. An excellent agreement between metabolic ratios obtained with both PET systems was found: R = 0.99 for structures with physiological tracer uptake, R = 0.96 for tumours. Conclusion: Simultaneous PET/MRI of the head and upper neck area is feasible with the new hybrid PET/MRI prototyp
Functionalized carbon nanotubes as transporters for antisense oligodeoxynucleotides
The use of DNA-based therapeutics requires efficient delivery systems to transport the DNA to their place of action within the cell. To accomplish this, we investigated multiwalled carbon nanotubes (pristine MWCNT, p-MWCNT) functionalized with hydroxyl groups via 1,3-dipolar cycloaddition. In this way, we have obtained MWCNT-f-OH with improved stability in aqueous dispersions which is an advantageous property for their use in cellular environments. Afterwards, a carrier strand oligodeoxynucleotide (CS-ODN) was adsorbed to MWCNT-f-OH followed by hybridization with a therapeutic antisense oligodeoxynucleotide (AS-ODN). The amount of adsorbed CS-ODN, as well as the complementary AS-ODN and a non-complementary oligodeoxynucleotide (NS-ODN) as reference, was directly measured by radionuclide labeling of ODNs. We show that subsequent release of AS-ODNs and NS-ODNs was possible for MWCNT-f-OH above the melting temperature of AS-ODNs at 80 °C and under physiological conditions at different pH values at 37 °C. We also show a very low influence of p-MWCNT and MWCNT-f-OH on the cell viability of the bladder carcinoma (BCa) cell line EJ28 and that both MWCNT types were internalized by EJ28. Therefore, MWCNT-f-OH represents a promising carrier able to transport and release AS-ODNs inside cells
Investigation of the Peptide Adsorption on ZrO<sub>2</sub>, TiZr, and TiO<sub>2</sub> Surfaces as a Method for Surface Modification
Specific surface binding peptides
offer a versatile and interesting possibility for the development
of biocompatible implant materials. Therefore, eight peptide sequences
were examined in regard to their adsorption on zirconium oxide (ZrO<sub>2</sub>), titanium zircon (TiZr), and titanium (c.p. Ti). Surface
plasmon resonance (SPR) measurements were performed on Ti coated sensor
chips to determine the kinetics of the interactions and kinetic rate
constants (<i>k</i><sub>on</sub>, <i>k</i><sub>off</sub>, <i>K</i><sub>D</sub>, and <i>R</i><sub>max</sub>). We also investigated the interactions which are
present in our system. Electrostatic and coordinative interactions
were found to play a major role in the adsorption process. Four of
the eight examined peptide sequences showed a significant adsorption
on all investigated materials. Moreover, the two peptides with the
highest adsorption could be quantified (up to 370 pmol/cm<sup>2</sup>). For potential biomaterials applications, we proved the stability
of the adsorption of selected peptides in cell culture media, under
competition with proteins and at body temperature (37 °C), and
their biocompatibility via their effects on the adhesion and proliferation
of human mesenchymal stem cells (hMSCs). The results qualify the peptides
as anchor peptides for the biofunctionalization of implants