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At least 343 records · Page 19Linked to original sources
PubMed1975

Evaluation of silicon and germanium retention in rat tissues and diatoms during cell and organelle preparation for electron probe microanalysis.

Chemical, radiochemical and x-ray microanalysis assays were used to define parameters of silicon (Si) retention during preparation og biologic samples (rat liver, spleen, kidney, lung, diatoms and cell organelles) for x-ray microanalysis, Due to its longer half-life 68-Fe was used in some cases to trace SI. Leaching of Si from cells and organelles by the aqueous preparation media was overcome by use of the freeze-substitution process. Cells were treated with 30% glycerol hypertonic sucrose medium to reduce ice damage. Embedment in Spurr's low viscosity epoxy resin medium caused no apparent Si loss. A semiquantitative evaluation showed 0.5 x 10-8 to 0.3 x 10-17 g detectable Si in isolated rat liver mitochondria in thin sections, which is within the instrument's range of detection. This study indicateds that the presence of Si in the mitochondria is not the rsult of contamination.

Animals↗
PubMed1976

A comparison of clinical results in brain scanning using germanium semiconductor detectors and sodium iodide detectors.

A comparison is presented of the image quality obtained with a 70 mm Ge(Li) detector scanner and with routine techniques based on NaI (Tl) detectors. One hundred and sixty-five pairs of brain scans have been examined for which the patients have been scanned with both Ge(Li) and NaI (Tl) detectors. It is concluded that no major difficulties exist in introducing Ge(Li) scanners and that while a comparison of scans from different instruments is difficult there is evidence that improved diagnostic information may be obtained from scanners with Ge(Li) detectors.

Brain Diseases↗
PubMed2004

Characterization of supported cylinder-planar germanium waveguide sensors with synchrotron infrared radiation.

Cylinder-planar Ge waveguides are being developed as evanescent-wave sensors for chemical microanalysis. The only non-planar surface is a cylinder section having a 300-mm radius of curvature. This confers a symmetric taper, allowing for direct coupling into and out of the waveguide's 1-mm(2) end faces while obtaining multiple reflections at the central <30-microm-thick sensing region. Ray-optic calculations indicate that the propagation angle at the central minimum has a strong nonlinear dependence on both angle and vertical position of the input ray. This results in rather inefficient coupling of input light into the off-axis modes that are most useful for evanescent-wave absorption spectroscopy. Mode-specific performance of the cylinder-planar waveguides has also been investigated experimentally. As compared to a blackbody source, the much greater brightness of synchrotron-generated infrared (IR) radiation allows a similar total energy throughput, but restricted to a smaller fraction of the allowed waveguide modes. However, such angle-selective excitation results in a strong oscillatory interference pattern in the transmission spectra. These spectral oscillations are the principal technical limitation on using synchrotron radiation to measure evanescent-wave absorption spectra with the thin waveguides.

Biosensing Techniques↗
PubMed2006

Attenuated total internal reflection infrared microspectroscopic imaging using a large-radius germanium internal reflection element and a linear array detector.

The number of techniques and instruments available for Fourier transform infrared (FT-IR) microspectroscopic imaging has grown significantly over the past few years. Attenuated total internal reflectance (ATR) FT-IR microspectroscopy reduces sample preparation time and has simplified the analysis of many difficult samples. FT-IR imaging has become a powerful analytical tool using either a focal plane array or a linear array detector, especially when coupled with a chemometric analysis package. The field of view of the ATR-IR microspectroscopic imaging area can be greatly increased from 300 x 300 microm to 2500 x 2500 microm using a larger internal reflection element of 12.5 mm radius instead of the typical 1.5 mm radius. This gives an area increase of 70x before aberrant effects become too great. Parameters evaluated include the change in penetration depth as a function of beam displacement, measurements of the active area, magnification factor, and change in spatial resolution over the imaging area. Drawbacks such as large file size will also be discussed. This technique has been successfully applied to the FT-IR imaging of polydimethylsiloxane foam cross-sections, latent human fingerprints, and a model inorganic mixture, which demonstrates the usefulness of the method for pharmaceuticals.

Dermatoglyphics↗
PubMedDate not supplied

Determination of germanium in some plants and animals.

The Ge contents of plants and animals were investigated by a wet ashing procedure by hydride generation and inductively coupled plasma atomic emission spectrometry with flow injection. The analytical results obtained indicated that Ge contents widely vary in plant and animal kingdoms in the range of 8-302 ppb.

Animals↗
PubMed2003

Germanium oxide enhances the radiosensitivity of cells.

We investigated here the combined effect of GeO(2) and radiation on cell viability. Cells were treated with 0 to 22 mM GeO(2) for 12 h followed by 1 Gy X irradiation. A synergistic cytotoxic effect was observed for the combined treatment with a dose-dependent reduction of cell viability. Complete survival curves showed a 2.3- and 2.75-fold increase in radiosensitivity for 50% cell death in the presence of 5 and 15 mM GeO(2), respectively. The increased radiosensitivity also occurred when GeO(2) was given either 4 h prior to irradiation or immediately after radiation exposure. GeO(2) did not affect the total soluble thiol content or the activities of catalase and glutathione S-transferase. Analysis of the production of reactive oxygen species (ROS) revealed that the combined treatment dramatically increased the synthesis of ROS. Addition of N-acetyl cysteine (NAC, 20 mM) decreased the production of ROS in cells. NAC, however, increased cell viability only slightly after treatment with GeO(2) and radiation. Thus increased production of ROS makes little or no contribution to the observed death. The combination of GeO(2) and X radiation, however, significantly increased the frequency of DNA double-strand breaks (DSBs). Notably, the presence of GeO(2) also reduced the efficiency of DNA repair. We conclude that treatment with GeO(2) followed by X irradiation increases DNA DSBs and cell death.

Acetylcysteine↗
PubMed1984

Transport of calcium, germanium and rubidium ions in rice seedlings in deuterium oxide.

Deuterium oxide affected all types of transport processes of ions in rice seedlings. The processes of the active transport of Rb+, the passive diffusion of Ca2+, and the preferential and specific absorption of Ge by the seedlings in D2O solutions, were suppressively distorted by D2O. The suppressive effect on the translocation of all ions studied and the absorption of Rb+, was greater with higher concentrations of D2O. However, clear-cut relations of the effect of increasing D2O concentrations on the ion transport were not obtained. The extent of the replacement of H2O by D2O in the plant appeared to affect the movement of ions in the plant.

Biological Transport↗
PubMed1998

[Study on certified reference material of germanium in Ganoderma lucidum].

Analytical reference material of Ge in Ganoderma lucidum is designed and prepared for accurete analysis, monitoration and evaluation in trades of farming, forestry, medicine and food hygiene for Ge. It is used in technical training, technical assessing, monitoring, data arbitrating and analytic method verifing for professional supervisors. This reference material has been certified by graphitic oven atomic absorption spectrometry, hydride spectrophotometry, polarography, chemical separation spectrophotometry, atomic fluorescence method and x-ray fluorescence method. According to Grubb's law to judge the data of each group, it is confirmed that all of seven groups certified crude data are normal distribution by checking normality D. The arithmatic mean value of all data is 0.38 microgram/g. Standard deviation is 0.08 microgram/g.

Drugs, Chinese Herbal↗