Search results for " microscopy"
showing 10 items of 1617 documents
The nature of radiohaloes in biotite: Experimental studies and modeling
2001
Several micro-techniques (confocal laser-Raman microprobe, optical absorption micro-spectroscopy, high-resolution transmission electron microscopy, electron microprobe analysis) were employed in the detailed characterization of radiohaloes in biotites from two Variscan rocks from Germany. The studied biotites are intermediate members of the phlogopite-annite series with Mg/Fe 2+ ratios in the range 1.6–1.0. Radiohaloes in biotite resulted from the impact of 4 He cores (α-particles) emitted from actinide-bearing inclusions. Monte Carlo simulations yielded α ( 238 U, 235 U, and 232 Th series) penetration ranges in biotite between 12.5 and 37.3 μm, which are in reasonable agreement with the ob…
Long-Range Order Induced by Intrinsic Repulsion on an Insulating Substrate
2015
An ordered arrangement of molecular stripes with equidistant appearance is formed upon the adsorption of 3-hydroxybenzoic acid onto calcite (10.4) held at room temperature. In a detailed analysis of the next-neighbor stripe distances measured in noncontact atomic force microscopy images at various molecular coverages, we compare the observed stripe arrangement with a random arrangement of noninteracting stripes. The experimentally obtained distance distribution deviates substantially from what is expected for a random distribution of noninteracting stripes, providing direct evidence for the existence of a repulsive interaction between the stripes. At low molecular coverage, where the averag…
Accurate and precise lattice parameters by selected-area electron diffraction in the transmission electron microscope
2009
8 páginas, 6 figuras, 7 tablas.
Preferential Type II Muscle Fiber Damage From Plyometric Exercise
2012
Context: Plyometric training has been successfully used in different sporting contexts. Studies that investigated the effect of plyometric training on muscle morphology are limited, and results are controversial with regard to which muscle fiber type is mainly affected. Objective: To analyze the skeletal muscle structural and ultrastructural change induced by an acute bout of plyometric exercise to determine which type of muscle fibers is predominantly damaged. Design: Descriptive laboratory study. Setting: Research laboratory. Patients or Other Participants: Eight healthy, untrained individuals (age = 22 ± 1 years, height = 179.2 ± 6.4 cm, weight = 78.9 ± 5.9 kg). Intervention(s): Partici…
Dentin tubule orientation determines odontoblastic differentiation in vitro: A morphological study.
2019
Odontoblasts are post-mitotic cells responsible for maintenance of the dentin, and are therefore important for dental health. In some cases, irreversible pulpitis leads to necrosis and consequently death of odontoblasts. Regenerative endodontics (RE) uses the concept of tissue engineering to restore the root canals to a healthy state, allowing for continued development of the root and surrounding tissue. Human dental pulp stem cells (hDPSCs) have been successfully used in RE to restore odontoblast function. Surface microgeometry is one of the most important factors involved in the induction of differentiation of hDPSCs into odontoblast-like cells. Although different authors have demonstrate…
Role of nitric oxide synthase isoforms for ophthalmic artery reactivity in mice.
2014
Abstract Nitric oxide synthases (NOS) are involved in regulation of ocular vascular tone and blood flow. While endothelial NOS (eNOS) has recently been shown to mediate endothelium-dependent vasodilation in mouse retinal arterioles, the contribution of individual NOS isoforms to vascular responses is unknown in the retrobulbar vasculature. Moreover, it is unknown whether the lack of a single NOS isoform affects neuron survival in the retina. Thus, the goal of the present study was to examine the hypothesis that the lack of individual nitric oxide synthase (NOS) isoforms affects the reactivity of mouse ophthalmic arteries and neuron density in the retinal ganglion cell (RGC) layer. Mice defi…
PRCD is concentrated at the base of photoreceptor outer segments and is involved in outer segment disc formation.
2019
Abstract Mutations of the PRCD gene are associated with rod-cone degeneration in both dogs and humans. Prcd is expressed in the mouse eye as early as embryonic day 14. In the adult mouse retina PRCD is expressed in the outer segments of both rod and cone photoreceptors. Immunoelectron microscopy revealed that PRCD is located at the outer segment rim, and that it is highly concentrated at the base of the outer segment. Prcd-knockout mice present with progressive retinal degeneration, starting at 20 weeks of age and onwards. This process is reflected by a significant and progressive reduction of both scotopic and photopic electroretinographic responses, and by thinning of the retina, and spec…
Peripherin-2 couples rhodopsin to the CNG channel in outer segments of rod photoreceptors.
2014
Outer segments (OS) of rod photoreceptors are cellular compartments specialized in the conversion of light into electrical signals. This process relies on the light-triggered change in the intracellular levels of cyclic guanosine monophosphate (cGMP), which in turn controls the activity of cyclic nucleotide-gated (CNG) channels in the rod OS plasma membrane. The rod CNG channel is a macromolecular complex that in its core harbors the ion-conducting CNGA1 and CNGB1a subunits. To identify additional proteins of the complex that interact with the CNGB1a core subunit we applied affinity purification of mouse retinal proteins followed by mass spectrometry. In combination with in vitro and in viv…
Evaluation of reverse transcription and polymerase chain reaction (RT/PCR) for the detection of rotaviruses: applications of the assay.
1996
Summary Our aim was to evaluate the reverse transcription and polymerase chain reaction (RT/PCR) technique for the detection of rotavirus shedding by infected children as a routine diagnostic procedure, in comparison to the enzyme-linked immunosorbent assay (ELISA), electron microscopy (EM) and polyacrylamide gel etectrophoresis (PAGE) of rotavirus double stranded RNA. Two-hundred and twenty stool specimens were collected from infants and young children with diarrhoea, and 10–20% faecal suspensions were made. Several methods of rotavirus dsRNA extraction were assayed. Electrophoretic analysis of viral RNA was carried out on 10% polyacrylamide gols followed by silver staining. RT/PCR was per…
Effect of three prophylaxis methods on surface roughness of giomer
2010
Objectives: Plaque and stains are removed by prophylaxis methods from tooth surfaces. Since prophylaxis methods can have a detrimental effect on the surface finish of restorations, the aim of this in vitro study was to investigate the effect of three prophylaxis methods, including pumice with rubber cup, pumice with brush, and air-powder polishing device (APD) on the surface roughness of giomer. Study design: Sixty four cylindrical giomer (Beautifil II, Shofu) samples with a diameter of 6 mm and a height of 2 mm were used. Subsequent to a 3-month period of storage in distilled water at 37ºC, the samples were randomly divided into four groups of 16. In group 1 (control), no prophylaxis proce…