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S Patanè

Publications and source records attributed to S Patanè.

At least 19 recordsLinked to original sources
PubMed2003

Near-field Raman imaging of morphological and chemical defects in organic crystals with subdiffraction resolution.

In this study we report on the application of an aperture near-field optical microscope for Raman imaging of organic materials. Spectral analysis and detailed Raman imaging are performed with integration times of 100 ms per point, without the aid of field enhancement effects. The studied samples consist of two high Raman-efficiency molecular samples: a 7,7',8,8'-tetracyanoquinodimethane crystal showing surface defects and a 7,7',8,8'-tetracyanoquinodimethane thin film characterized by the presence of submicrometre-sized organometallic copper-salt complexes. In the first case, the effect of the surface deformation was studied, whereas in the second sample we were able to chemically image the formation of salt complexes. Subdiffraction resolution was achieved in both studies.

Crystallization↗
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↗
PubMed1989

Effects of calcitonin on morphine tolerance and withdrawal syndrome in morphine physically dependent rats.

We investigated the effect of acute or chronic peripheral administration of [Asu1.7]eel-calcitonin on the development of tolerance to the analgesic effect of morphine and on the naloxone-precipitated withdrawal syndrome in morphine-dependent rats. Neither the analgesic effect of acute morphine nor the development of tolerance to the antinociceptive effect of this drug was modified by calcitonin. However, the chronic but not the acute administration of calcitonin attenuated some signs and symptoms of morphine withdrawal.

Animals↗
PubMedDate not supplied

Morphologic variations in bacteria under stress conditions: near-field optical studies.

The morphologic and structural variations suffered by cells of a population of Pseudomonas aeruginosa ATCC 27853 under stress conditions were investigated by using scanning near-field optical microscopy. The analysis of the images, supported by microbiological data, showed that the bacteria evolved from the initial distribution of rod-shaped cells of standard size to a population with structural and morphologic modifications. The detection of variations in the optical reflectivity over a subwavelength scale (< or = 100 nm), combined with the concurrently acquired topographical signal, allowed the visualisation of rod-shaped bacteria going towards a lytic process and entire "U"-shaped cells. In the latter cells, which derived from a morphology refolding of rod bacteria, cellular matter seemed to rearrange itself to attain a coccoid stress resistant form, responsible for the residual viability of the population.

Biomass↗