Biomedical subjects

Christoph Dietrich

Publications and source records attributed to Christoph Dietrich.

3 recordsLinked to original sources

PubMed2003

Computer-generated stratified diffractive optical elements.

We present what is to our knowledge a new type of diffractive optical element (DOE), the computer-generated stratified diffractive optical element (SDOE), a hybridization of thin computer-generated DOEs and volume holograms. A model and several algorithms for calculating computer-generated SDOEs are given. Simulations and experimental results are presented that exhibit the properties of computer-generated SDOEs: the strong angular and wavelength selectivity of SDOEs makes it possible to store multiple pages in a computer-generated SDOE, which can be read out separately (multiplexing). The reconstruction of an optimized SDOE has a higher quality than the reconstruction of optimized one-layer DOEs. SDOEs can be calculated to have only one diffraction order.

Journal Article↗

PubMed2002

Electrochemical metallization of self-assembled porphyrin monolayers.

Multifunctional sensor systems are becoming increasingly important in electroanalytical chemistry. Together with ongoing miniaturization there is a need for micro- and nanopatterning tools for thin electroactive layers (e.g. self-assembling monolayers). This paper documents a method for production of a micro-array of different metal-porphyrin monolayers with different sensor properties. A new method has been developed for the selective and local metallization of bare porphyrin monolayers by cathodic pulsing and sweeping. The metal-porphyrin monolayers obtained were characterized by cyclic voltammetry. It was shown that porphyrin monolayers can be metallized with manganese, iron, cobalt, and nickel by use of the new method. It is expected that all types of metal-porphyrin monolayers can be produced in the same manner.

Journal Article↗

PubMedDate not supplied

Long-term follow-up of patients with microscopic endonasal dacryocystorhinostomy.

BACKGROUND: Stenosis of the nasolacrimal drainage system is a relatively frequent complication of acute or chronic inflammation, trauma, tumor, or congenital malformation. Symptoms include epiphora, intermittent purulent secretion, and swelling of the nasolacrimal sac. The principle of dacryocystorhinostomy (DCR) is to create an artificial opening of the lacrimal sac into the nasal cavity. This can be done via an external as well as an endonasal route. METHODS: In this retrospective study, we examined 74 microscopic endonasal DCRs. which were performed on 70 patients between 1990 and 2000. All of the 74 DCR operations had no major complications intraoperatively. RESULTS: Sixty DCR procedures (81.1%) were successful after a mean follow-up time of 3.18 years. This success rate is lower than those rates reported in the literature for the external approach, which range between 85 and 99%, although follow-up times were shorter in most of these studies. CONCLUSIONS: Advantages of the endonasal approach such as saving the medial palpebral ligament, the lacrimal pump mechanism, and the horizontal apparatus are obvious. If necessary, additional management of sinus, septal, and conchal disease can be performed simultaneously. Our results reveal that the microscopic endonasal approach is a safe and reliable procedure in the management of postsaccular or saccular nasolacrimal duct obstruction and is an alternative to the traditional external route.

Adolescent↗