Biomedical subjects

R Salzer

Publications and source records attributed to R Salzer.

6 recordsLinked to original sources

PubMed2001

Temperature dependence of the optical properties of CuMoO4.

CuMoO4 crystals reversibly change their color from green to brown upon heating, accompanied by a loss in transmittance. UV/VIS spectroscopic analysis revealed that these changes are due to particular electronic properties of the crystal instead of its chemical decomposition or structural change. Investigations were carried out in the temperature range 23-400 degrees C. The intensive green color of the crystal at room temperature is caused by a small transmission window between two absorption bands, the band gap of the crystal in the blue and the 3d9-->4p absorption of the Cu2+ ions in the red. With increasing temperature the band gap shifts towards longer wavelengths, and the crystal changes both color and transmittance. Spectroscopic features of the crystal are discussed together with the temperature dependence of its electrical resistance. Resistance measurements were performed simultaneously to the optical measurements.

Journal Article↗

PubMed2001

Internet-assisted exercises in structural analysis.

In this report we describe our experience in the analytical chemistry curriculum of teaching spectrometer principles and preparing spectroscopy laboratory exercises by means of virtual instruments. The benefits of the intensified preparation of laboratory exercises by virtual instruments will be evaluated with respect to the subsequent handling of real instruments. The utilization of in-house electronic media with Internet resources for elucidation and verification of a structural assignment will also be considered.

Journal Article↗

PubMed2000

Rapid access to infrared reference spectra of arbitrary organic compounds: scope and limitations of an approach to the simulation of infrared spectra by neural networks

Substance identification by infrared spectroscopy is performed by comparison of the experimental spectrum with a reference spectrum from a printed compilation or a database. If the analyzed compound can not be found in a database the corresponding reference spectrum has to be simulated. In order to achieve this, several reasonable candidates of structures for the compound at hand have to be conceived and for all these, infrared spectra have to be developed. The simulated spectrum that is most similar to the experimental suggests the correct structure. A rapid spectrum prediction method based on neural networks has been developed that supplies reference spectra for any organic compound. The scope and limitations of this method will be discussed on a test set of 16 compounds representing a broad range of organic chemistry.

Journal Article↗

PubMed1985

Aztreonam in the treatment of serious orthopedic infections.

Aztreozam was evaluated in the treatment of a variety of orthopedic infections. Included were 17 patients with osteomyelitis, three with purulent arthropathy with prostheses, and 16 with superficial infections secondary to trauma or surgical procedure. Pathogens were gram-negative bacilli sensitive to aztreonam. Concomitant antibiotics were administered for gram-positive cocci that were present initially or by superinfection. Infecting organisms included Pseudomonas aeruginosa (minimal inhibitory concentration 4 to 16 micrograms/ml), Serratia marcescens, Enterobacter cloacae, Enterobacter sakazakii, Morganella morganii, Citrobacter freundii, Proteus vulgaris, Proteus rettgeri, Acinetobacter calcoaceticus and others (all with minimal inhibitory concentrations less than 1.0 microgram/ml). Dosage of aztreonam was 2 to 8 g per day administered intravenously or intramuscularly for five to 52 days. Clinical and bacteriologic responses were adequate in all instances. Recurrences were observed in two individuals with osteomyelitis and one with purulent arthropathy. Adverse clinical or laboratory observations were infrequent and inconsequential.

Adult↗

PubMedDate not supplied

Retention behavior of humic substances in reversed phase HPLC.

Recovery as well as appearance and abundance (in percent) of different fractions of humic substances are found to depend on injected sample amounts in reversed phase HPLC. Sample amounts have been varied both by varying sample concentration and sample volume. In case of lowest amounts injected only two fractions were obtained for a commercial humic acid sodium salt, i.e. one for excluded molecules and one for hydrophobic components. The abundance of excluded molecules decreases upon increasing amounts injected. Another three fractions are obtained upon increasing amount injected: a hydrophilic fraction and two hydrophobic ones. This behavior is explained by auxiliary equilibria between excluded components and humic molecules previously adsorbed on the stationary phase.

Journal Article↗

PubMedDate not supplied

Infrared and Raman imaging of biological and biomimetic samples.

Established methods for imaging of biological or biomimetic samples, such as fluorescence and optical microscopy, magnetic resonance imaging (MRI), X-ray tomography or positron emission tomography (PET) are currently complemented by infrared (both near-IR and mid-IR) as well as Raman spectroscopic imaging, whether it be on a microscopic or macroscopic scale. These vibrational spectroscopic techniques provide a wealth of information without a priori knowledge of either the spectral data or the composition of the sample. Infrared radiation does not harm the organism, no electric potential needs to be applied, and the measurements are not influenced by electromagnetic fields. In addition, no extrinsic labeling or staining, which may perturb the system under investigation, has to be added. The immense volume of information contained in spectroscopic images requires multivariate analysis methodologies in order to effectively mine the chemical and spatial information contained within the data as well as to analyze a time-series of images in order to reveal the origin of a chemical or biochemical process. The promise and limitations of this new analytical tool are surveyed in this review.

Animals↗