Biomedical subjects

M Labardi

Publications and source records attributed to M Labardi.

3 recordsLinked to original sources

PubMed2003

A versatile multipurpose scanning probe microscope.

A combined scanning probe microscope has been developed that allows simultaneous operation as a non-contact/tapping mode atomic force microscope, a scattering near-field optical microscope, and a scanning tunnelling microscope on conductive samples. The instrument is based on a commercial optical microscope. It operates with etched tungsten tips and exploits a tuning fork detection system for tip/sample distance control. The system has been tested on a p-doped silicon substrate with aluminium depositions, being able to discriminate the two materials by the electrical and optical images with a lateral resolution of 130 nm.

Journal Article↗

PubMed2001

Optical near-field harmonic demodulation in apertureless microscopy.

Spatial derivatives of the optical fields scattered by a surface can be investigated by apertureless near-field optical microscopy by modulating sinusoidally the probe to sample distance and detecting the optical signal at the first and higher harmonics. Demodulation up to the fifth harmonic order has been accomplished on a sample of close-packed latex spheres by means of the silicon tip of a scanning interference apertureless microscope. The working principles of such microscope are reviewed. The experimental configuration used comprises a tuning-fork-based tapping-mode atomic force microscope for the distance stabilization, and a double-modulation technique for complete separation of the topography tracking from the optical detection. Simple modelling provides first indications for the interpretation of experimental data. The technique described here provides either artefact-free near-field optical imaging, or detailed information on the structure of the near fields scattered by a surface.

Journal Article↗

PubMed1988

Serum HBV DNA and intrahepatic hepatitis B core antigen (HBcAg) in chronic hepatitis B virus infection: correlation with infectivity and liver histology.

In this study we investigated the HBeAg/anti HBeAg status, the liver histological features, the intrahepatic localization of HBcAg, and the presence of serum HBV DNA in a group of 79 HBsAg-positive patients. We found a close relationship between the presence of HBV DNA and intrahepatic HBcAg in HBeAg-positive patients. Among the 56 anti-HBeAg-positive patients considered, 13 (23.2%) showed the presence of intrahepatic HBcAg and serum HBV DNA. In this group of patients, active viral replication was associated with a chronic inflammatory liver disease and particularly with CAH. Furthermore, a prevalent cytoplasmic localization of HBcAg was found in 66.6% of patients affected by CAH, showing that this peculiar distribution of HBcAg seems to be associated with a poor prognosis.

Adult↗