Search results for "focal"

Development and viability of biofilms grown on experimental abutments mimicking dental implants: an in vivo model

2019

Background To determine whether an experimental abutment mimicking the macro- and microstructure of a dental implant is a suitable method for recovering biofilm, and to describe the features of biofilms formed around such abutments on healthy implants. Material and Methods Experimental abutments were used in 15 patients without peri-implant diseases. After 14 days’ absence of dental hygiene in this area, the abutments were retrieved and analyzed through confocal laser scanning microscopy and scanning electron microscopy. The biofilm formation on the surface of the first 5 abutments was determined by a fluorescence-staining method using SYTO9 nucleic acid stain. In order to study the biofilm…

Near-field probing of active photonic-crystal structures

2002

We report a study of the optical near field of an active integrated component operating near the 1.55-mum telecommunications wavelength. The device is based on a two-dimensional photonic crystal etched in a suspended InP membrane. Topographic as well as optical information is collected by use of a scanning near-field optical microscope in collection mode, providing information about the local distribution of the losses.

Combination of Confocal Raman Spectroscopy and Electron Microscopy on the Same Individual Bundles of Single-Walled Carbon Nanotubes

2002

We report a method to investigate the same individual single-walled carbon nanotube (SWNT) bundles with both transmission electron microscopy (TEM) and Raman spectroscopy. Free-standing individual bundles are obtained by depositing a solution of suspend SWNTs on a carbon film with a regular pattern of holes, which can be localized by TEM and also by confocal Raman microscopy. While most of the TEM images predict that the bundles consist of tubes with a similar diameter, we will show that occasionally a certain tube diameter can be associated with a particular radial breathing mode frequency of the Raman spectrum. Single-walled carbon nanotubes (SWNTs) are one-dimensional molecular structure…

Interferometric Z-scan method for thermo-optical effect studies

2021

We demonstrated a new approach to measuring third-order nonlinear optical effects using an experimental setup incorporating both Z-scan and Mach-Zehnder interferometer methods. This method could be especially purposive for thermo-optical effect studies as it can simultaneously probe thermal gradient profile as well as absolute temperature changes induced by an optical beam. The experimental setup was tested using chloroform. Experimental measurements were carried out using 1064 nm Nd:YAG laser with 8 ns pulse width and 40 kHz pulse repetition rate. The measured nonlinear refractive index of chloroform was mainly induced by the thermo-optical effect. As thermo-optical response depends on bea…

Imaging of photonic nanopatterns by scanning near-field optical microscopy

2002

We define photonic nanopatterns of a sample as images recorded by scanning near-field optical microscopy with a locally excited electric dipole as a probe. This photonic nanopattern can be calculated by use of the Green’s dyadic technique. Here, we show that scanning near-field optical microscopy images of well-defined gold triangles taken with the tetrahedral tip as a probe show a close similarity to the photonic nanopattern of this nanostructure with an electric dipole at a distance of 15 nm to the sample and tilted 45° with respect to the scanning plane.

Outline and arrangement of enamel rods in human deciduous and permanent enamel. 3D-reconstructions obtained from CLSM and SEM images based on serial …

2001

Human enamel rods were made visible continuously from the dentino-enamel junction (DEJ) up to the enamel surface. From 12 teeth (1st and 2nd dentition) enamel blocks from the cervical third were prepared with perpendicular planes, embedded in resin, and ground down in steps of 15 microm parallel to the enamel surface. Enamel rods were made visible by acid etching (35% H3PO4, 45 s), sputtered and examined in the scanning electron microscope (SEM). Prior to this, the enamel blocks were viewed under the CLSM and optical sections at distances of 2 microm were obtained, starting in the same plane as the grinding surface. The outlines of the rods were digitized and reconstructed three dimensional…

Konfokale Laser Scanning Mikroskopie (CLSM) kortikalen Knochens – Vergleichende Darstellung mit konventioneller Mikroskopie

1997

Functional and Molecular Imaging with Confocal Laser Endomicroscopy

2007

In vivo functional and molecular imaging is an emerging new field in gastroenterology. Ex vivo histopathological examination of tissue specimens offers a snapshot view into the tissue, capturing the moment at which the biopsy has been taken. The specimen is subjected to the fixation and staining process, making it prone to artefact. In vivo imaging with confocal endomicroscopy, however, offers the possibility of dynamic monitoring of the living tissue without the need for fixation. To our current knowledge, staining with intravenous fluorescein sodium or topical acriflavine hydrochloride does not alter tissue properties in a way that could influence biological processes. Therefore, with con…

A New Statistical Reconstruction Method for the Computed Tomography Using an X-Ray Tube with Flying Focal Spot

2021

Abstract This paper presents a new image reconstruction method for spiral cone- beam tomography scanners in which an X-ray tube with a flying focal spot is used. The method is based on principles related to the statistical model-based iterative reconstruction (MBIR) methodology. The proposed approach is a continuous-to-continuous data model approach, and the forward model is formulated as a shift-invariant system. This allows for avoiding a nutating reconstruction-based approach, e.g. the advanced single slice rebinning methodology (ASSR) that is usually applied in computed tomography (CT) scanners with X-ray tubes with a flying focal spot. In turn, the proposed approach allows for signific…

A comparison of three different micro-tomography systems for accurate determination of microvascular parameters

2008

The investigation of micro-vessel dimensions in 3D is currently problematic due to their complex structures and fine scale. Quantification of vascular parameters is important in several fields of biomedicine; including embryogenesis, wound healing, diseases characterized by uncontrolled angiogenesis (e.g. tumor growth and metastasis) and the development of implantable bio-materials where a functional vascular supply is critical to their successful integration into host tissue. However, techniques that can resolve the micron-scaled features of these capillary beds, such as scanning electron and confocal microscopy, do not allow for total image reconstitution in 3 D in thick tissue samples [1…