Biomedical subjects

K C Tran

Publications and source records attributed to K C Tran.

5 recordsLinked to original sources

PubMed1996

Atomic spectroscopy with surface wave plasmas.

The use of microwave induced plasmas, particularly of surface wave plasmas, as detectors in atomic emission spectrometry for elemental analysis is reviewed. Surface wave plasmas have been produced at low HF power and used as gas chromatographic detectors. The analytical performances for the detection of non-metals with a Fourier transform spectrometer and a two-channel filter unit are reported. The excitation behavior of non-metals in helium-based mixed gas-plasmas has also be studied. In particular, the effect of power and of nitrogen concentration on the bromine emission has been systematically investigated. A nine-fold improvement of the detection limits for bromine can be obtained in a high power (900 W) helium-nitrogen (0.1-0.2%) plasma.

Journal Article↗

PubMed1996

Rules and regulations of the Government of Vietnam on collection and exportation of biological materials.

Situated in Southeast Asia, with a tropical monsoon climate, Vietnam is covered by tropical rain forests over one-quarter of its surface. Forests have been extremely important in the country's economy and they will be essential in its future development. Forests contribute directly to the economy through the provision of building materials and energy and indirectly through foreign exchange earnings, which amount to about US$200 million annually. Forests play a key role in the conservation of biodiversity. They protect watersheds and thus contribute to flood control and water management in the highly productive delta regions. In order for the forests to contribute to the national economy, strong forest management institutions and proper policies are necessary. Forest land use and exploitation should be strictly controlled, and effective programs must be developed. The potential of the forests can only be realized on a sustainable basis through significant changes in current practices.

Commerce↗

PubMed1991

Organ-specific crystalline structures of ferritin cores in beta-thalassemia/hemoglobin E.

The cores of ferritins isolated from different organs of human subjects with beta-thalassemia/hemoglobin E (beta-thal/HbE) disease have different size distributions and crystallinities depending on the source organ. These patients have not been treated by hypertransfusion regimen or iron chelation therapy. beta-Thal/HbE spleens and livers yield ferritin cores which are less crystalline than those isolated from normal spleens and livers, reflecting the more rapid deposition of iron in the diseased state. Ferritins isolated from the hearts and pancreases of beta-thal/HbE subjects were found to have larger, more crystalline cores than those from the beta-thal/HbE livers and spleens, possibly as a consequence of the role of the heart and pancreas as long-term iron deposition sites in this iron overload pathology.

Ferritins↗

PubMed1990

Beta-thalassaemia/haemoglobin E tissue ferritins. I: Purification and partial characterization of liver and spleen ferritins.

Ferritins from liver and spleen of both beta-thalassaemia/haemoglobin E (HbE) and non-thalassaemic patients were purified by heating a methanol-treated homogenate, followed by molecular exclusion chromatography. The concentrations of ferritins in the beta-thalassaemia/HbE liver and spleen were calculated as 3.8 and 2.0 mg/g wet tissue. The beta-thalassaemia/HbE ferritin iron/protein ratios were higher than those of normal ferritins. On PAGE, all ferritins gave a single major monomeric band with only very small differences in their mobility. Ferritins from thalassaemic patients also possessed bands corresponding to oligomers. On SDS/PAGE, all ferritins were resolved into two major subunits: H and L with L subunit predominating. While the isoferritin profiles of ferritins from beta-thalassaemia/HbE liver and spleen were similar to each other and to those of normal liver and spleen, some extra bands were present in the acidic region. The microstructure of these pathological ferritins appears to result, to a large degree, from the particular nature and amount of iron loading present.

Electrophoresis, Polyacrylamide Gel↗

PubMed1990

Beta-thalassaemia/haemoglobin E tissue ferritins. II: A comparison of heart and pancreas ferritins with those of liver and spleen.

Tissue ferritins from beta-thalassaemia/haemoglobin E heart and pancreas were characterized by native PAGE, SDS/PAGE and isoelectric focussing, and compared with those isolated from corresponding liver and spleen tissue. On PAGE, all ferritins consisted of a single band assigned to the protein monomer. Small differences in electrophoretic mobility were found between the bands. The ferritins were resolved by SDS/PAGE into two major subunits, H and L, corresponding to molecular masses of 22.5 kDa and 19 kDa, respectively. The L subunit was predominant in all cases. The isoferritin profiles of all tissue ferritins were remarkably similar, consisting of a complex pattern of bands which were appreciably more basic than those obtained for horse spleen ferritin. The subunit composition and isoferritin profiles of the four tissue ferritins almost certainly reflect the defense mechanism of the body in synthesizing in all four tissue types a more stable long-term iron-storage isoferritin in order to detoxify and store the excess iron present due to the pathological condition of beta-thalassaemia/HbE.

Electrophoresis, Polyacrylamide Gel↗