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Biomedical subjects

J A Li

Publications and source records attributed to J A Li.

6 recordsLinked to original sources
PubMed2001

Observation of a metastable periodic structure for the (001) surface of KTaO3 after cleaving in situ.

Helium atom diffraction experiments carried out under ultrahigh vacuum conditions on a freshly cleaved (001) surface of KTaO3 reveal metastable features which decay over a period of several hours. The initial He diffraction pattern contains large scattering intensity satellite peaks very close to the specular reflection beam. As time from cleaving elapses, the satellite intensities diminish virtually to zero while the specular intensity increases, and the diffraction pattern evolves into one consistent with the (1x1) bulk termination surface. The data are compared with model calculations for scattering from a series of terraces at two heights with a distribution of terrace lengths [Surf. Sci. 384, 15 (1997)].

Journal Article↗
PubMed1990

Immunofluorescent studies for alpha-actinin in cultured cardiomyopathic hamster heart cells.

Primary cultures of cardiac myocytes from normal and genetically cardiomyopathic (CM) newborn hamsters (strain UM X7.1) were analyzed by indirect immunofluorescent microscopy after 3, 5, 7, and 9 days in culture. The cultures were fixed in cold acetone and immunostained by an indirect method using FITC-labelled anti-alpha-actinin to label the myofibrillar Z bands. Most normal and CM myocytes appeared round in shape after 3 days in culture. Normal cardiac myocytes began to exhibit cytoplasmic projections after 5 days in culture and their myofibrils usually showed parallel arrangements with respect to each other. The cardiac cells from CM hearts showed an obvious myofibril disarray. Moreover, projections formed later than normal. As the size of the cells increased, more and more projections formed in normal hamster myocytes during development. By contrast, most of the cardiomyopathic myocytes showed few projections even as late as 9 days in culture. Hence, the number of projections per cell was much less in cardiomyopathic myocytes than in normal, especially after 7 and 9 days in culture. These results suggest that cardiomyopathic cells have abnormal shapes in culture and, in particular, fail to form projections as in normal cells. Whether this unusual behavior is related to an abnormality of the membranes or cytoskeletal system in cardiomyopathic heart cells or to some other factor requires further study.

Actinin↗
PubMed1990

Single camera photogrammetric technique for restricted 3D motion analysis.

The purpose of this study was to use a single camera to determine the true elbow flexion angle with the arm plane oriented arbitrarily with respect to the camera. A mathematical theory was developed and a mechanical arm model was constructed to validate the theory. A static weightlifting skill was analysed to investigate the viability of the technique on the human subject. The validation of the theory showed the error associated with the elbow flexion angle was reduced from as high as 108 degrees when uncorrected to within 3 degrees when corrected by the technique. The elbow flexion angle of the human arm can be calculated to within 6 degrees of error for static weightlifting skill analysis.

Algorithms↗
PubMed1990

The expression of the Autographa californica nuclear polyhedrosis virus genome in insect cells.

This report presents a synopsis of recently published work in our laboratory on the molecular biology of the insect baculovirus Autographa californica nuclear polyhedrosis virus (AcNPV). The following studies have been summarized. (1) On the mode of transcription of the AcNPV genome in insect cells. (2) Translation of proteins encoded in the 81.2 to 85.0 map unit segment of AcNPV. (3) Inserts of insect cell DNA in the AcNPV genome. (4) Expression of influenza (fowl plague) virus haemagglutinin in Spodoptera frugiperda insect cells, and successful immunization of chickens. (5) Synthesis of the influenza virus haemagglutinin in insect larvae by recombinant AcNPV. This insect virus system will continue to serve as a model for research on the molecular biology of insects. Moreover, the baculovirus system has been recognized as a very efficient and safe eukaryotic expression vector.

Animals↗
PubMed1989

[A study on the promotion of adhesion properties of adhesives to metals treated by positive oxidation].

The adhesion to three alloys: Durabond, GH30 and soft Co-Cr, by PE adhesive was investigated. The surfaces of metals were treated by polishing, sand-blasting, positive-oxidation and complex processing in order to test the tensile bond strengths between metals and PE adhesive; to study the effects of the surface treatment of metals on adhesive properties; and to compare the tensile strength with that from the control experiment with EB composite resin and Panavia-EX resin under the same conditions. The results showed the mean tensile bond strengths between PE adhesive and Durabond, GH30 and soft Co-Cr alloys after the treatment of sandblasting and positive oxidation were 214.65 +/- 51.68 kg/cm2, 372.88 +/- 21.88 kg/cm2 and 349.21 +/- 48.32 kg/cm2 respectively, displaying better adhesive properties and stability of resistance to water.

Adhesives↗