Search results for " microscopy"

Structure determination and homogeneous optical properties of CdS/HgS quantum dots

1997

The structural and optical properties of heterogeneous semiconductor nanoparticles consisting of CdS and HgS are investigated by High Resolution Electron Microscopy (HRTEM) and selective spectroscopy like Hole Burning (HB) and Fluorescence Line Narrowing (FLN). The HRTEM study shows that epitaxy is possible in nanocrystals, provided the crystallites have well defined faceted shapes to begin with. From the HB- and FLN experiments homogeneous absorption and fluorescence spectra are calculated. It could be shown that the absorption is coupled to HgS-like phonons (250 cm -1 ) whereas the emission frequency is closer to the LO phonon frequency of CdS.

Minireview: Nicotinic Acetylcholine Receptors on Hippocampal Neurons: Distribution on the Neuronal Surface and Modulation of Receptor Activity

1997

The recent development of a technique that uses infrared microscopy for the visualization of well-defined areas on the surface of neurons, and a computerized system of micromanipulators led to the discovery that functional nicotinic acetylcholine receptors (nAChRs) are expressed at higher density on the dendrites than on the soma of rat hippocampal neurons. The finding that the expression of alpha-bungarotoxin-sensitive, alpha 7-bearing, nAChRs and dihydro-beta-erythroidine-sensitive, alpha 4 beta 2 nAChRs tends to increase along the dendritic length suggests that these receptors may be highly involved in the integration of synaptic functions in hippocampal neurons. The present report also …

Leaf epicuticular waxes effects egg parasitoid’s response to host adult footprint contact kairomone

2009

Chemical footprints left behind by true bugs are perceived as a contact kairomones by scelionid egg parasitoids. In the system Nezara viridula and its egg parasitoid Trissolcus basalis, previous studies have shown that the kairomone mediating such behavior is part of N. viridula’s cuticular hydrocarbons. In this study, the effect of epicuticular waxes of leaves of broad bean, Vicia faba, on wasp response to footprints of N. viridula females are investigated. Plants with intact waxes layer were used (1) without host chemical contamination, or (2) contaminated by host female footprints. Mechanically de-waxed plants were tested (3) without host chemical contamination, or (4) de-waxed a few min…

Microscopy and Molecular biology techniques for the study biocenosis diversity in semi-confined environments

2010

This study is part of a wider conservation project of artistic and anthropological finds located in the Grotto of the Saints (Licodia Eubea, Alia, Sicily), and represents an opportunity for investigating the micro-and macro biological systems colonizing this particular environment. It is well-known that the bio-receptivity of surfaces is strongly related to its constituent materials and environmental parameters, whose effects promote the establishment of specific biotic communities. This is particularly true for caves, hypogea and semi-confined environments and, in particular for the Grotto of the Saints, where besides the presence of different nutrient sources, there are also high humidity…

FRESHWATER CYANOBACTERIA, IDENTIFIED BY MICROSCOPIC AND MOLECULAR INVESTIGATIONS ON A COLONIZED FOUNTAIN SURFACE: A CASE STUDY IN PALERMO (SICILY, IT…

2021

Cyanobacteria or blue algae are ubiquitously present in both fresh and brackish water environments. They also grow in conditions of high humidity, colonizing stones or monuments and fountain surfaces, and creating thick biofilms able to induce biodeterioration in the constituent materials of artefacts. As well as several photoautotrophic organisms, cyanobacteria belong to the microorganisms identified as primary colonizers, playing an important role in stone artwork deterioration. In this study, an analysis was made of the biofilm collected from the stone fountain of the Two Dragons in Palermo (Italy), revealing the presence of cyanobacterial colonies by optical microscopy, due to their pec…

Natural autofluorescence in archeological bone

2017

The human bone present a natural autofluorescence which is tipically induced by natural antibiotiscs absorbed by collagen and in part is due to phenomena not weel know and referred to an enigmatic endogenous fluophore. Is iintristing for us to see the autofluorescence in the various age of the observed samples.

Biocompatibility and staining properties of CdSe\CdS\SiO2 nanoparticles for in-vitro biomaterials characterization

2015

Semiconductor nanocrystals, known as quantum dots (QDs) display well-tuned emission spectra from ultraviolet to the infrared region. Their photostability is greatly enhanced compared to fluorophores making them suitable for optical bio-imaging. In this work we have studied the cytocompatibility of CdSe\CdS\SiO2 QDs towards bovine articular chondrocytes in order to establish if these nanoparticles could be used as staining system forcells in tissue engineering purposes. Studies of QDs uptake and cell viability were conducted through morphology evaluation and MTS test. The adhesion behavior of chondrocytes deposited onto scaffolds of a derivative of hyaluronic acid functionalized with octadec…

Marble and stone revetment and pavements: Context and provenance

2022

Earlier excavations and survey at Vagnari furnished hardly any evidence for the use of marble at the site, and so the vicus was considered to be a low status settlement, with only a few rooms having been elegant enough to decorate them with marble floors or revetment. The fragments recovered were not analysed scientifically to determine the location of the quarries from which the marbles came. Of particular interest, however, were two small fragments of inscriptions on white marble retrieved from the rubble fill dumped in the 4th century AD in the reservoir. These originally may have been attached, when intact, to votive or funerary monuments, suggesting that the occasional commemorative mo…

Degradation od Mater-Bi/wood flour biocomposites in active sewage sludge

2009

Mortars and Plasters under the Mosaics and the Wall Paintings of the Roman Villa at Piazza Armerina, Sicily

2010

The Roman Villa at Piazza Armerina in Sicily, built in many successive steps over the 2nd and 3rd centuries A.D., is renowned all over the world for both the wealth and the refinement of its mosaic floors. In February 2007 the Regional Government of Sicily started a restoration project of the whole archaeological site. The systematic survey and study of all decorative elements highlighted the value of wall paintings, which until then were almost unknown except for casual approaches to specific problems of conservation, carried on without any relation to the far and away famous mosaics. This paper shows the results of a physical chemical investigation of the mortars used for both floors and …