Unbiased estimation of particle number and sizes using the new stereological tools: the disector, the fractionator, the selector, and the nucleator — or just point-sampled intercepts

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100104200 ◽

1988 ◽

Vol 46 ◽

pp. 428-429

Author(s):

H.J.G. Gundersen

Keyword(s):

Particle Number ◽

Small Distance ◽

Parallel Plane ◽

Unbiased Estimation ◽

Severe Problem ◽

New Era ◽

Size And Shape ◽

Distinct Property ◽

Sectioned Tissue

Previously, all stereological estimation of particle number and sizes were based on models and notoriously gave biased results, were very inefficient to use and difficult to justify. For all references to old methods and a direct comparison with unbiased methods see recent reviews.The publication in 1984 of the DISECTOR, the first unbiased stereological probe for sampling and counting 3—D objects irrespective of their size and shape, signalled the new era in stereology — and give rise to a number of remarkably simple and efficient techniques based on its distinct property: It is the only known way to obtain an unbiased sample of 3-D objects (cells, organelles, etc). The principle is simple: within a 2-D unbiased frame count or sample only cells which are not hit by a parallel plane at a known, small distance h.The area of the frame and h must be known, which might sometimes in itself be a problem, albeit usually a small one. A more severe problem may arise because these constants are known at the scale of the fixed, embedded and sectioned tissue which is often shrunken considerably.

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Unbiased estimation of particle number using sections-an historical perspective with special reference to the stereology of glomeruli

Journal of Microscopy ◽

10.1111/j.1365-2818.1989.tb01470.x ◽

1989 ◽

Vol 153 (1) ◽

pp. 93-102 ◽

Cited By ~ 25

Author(s):

T. F. Bendtsen ◽

J. R. Nyengaard

Keyword(s):

Special Reference ◽

Historical Perspective ◽

Particle Number ◽

Unbiased Estimation

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Characteristics of Fake News and Misinformation in Greece: The Rise of New Crowdsourcing-Based Journalistic Fact-Checking Models

Journalism and Media ◽

10.3390/journalmedia2030025 ◽

2021 ◽

Vol 2 (3) ◽

pp. 417-439

Author(s):

Evangelos Lamprou ◽

Nikos Antonopoulos ◽

Iouliani Anomeritou ◽

Chrysoula Apostolou

Keyword(s):

Fake News ◽

Traditional Role ◽

Severe Problem ◽

New Era ◽

The Public ◽

The World ◽

Fact Checking ◽

Negative Impacts ◽

The Public Sphere

Fake news and misinformation are a menace to the public sphere, democracy, and society with sometimes irreversible consequences. Journalists in the new era seem not to be able or willing to play their traditional role of gatekeeper and social media have made the problem even more intense. The need for truth is unnegotiable in modern democracies. Nevertheless, non-true stories and misinformation dominate media outlets with severe consequences and negative impacts on societies all over the world. Fact-checking platforms based on crowdsourcing strategies or automated digital websites might be the answer to a problem that is escalating. Initially, in order to tackle such a severe problem, researchers and experts have to monitor its characteristics. Very few research attempts have been conducted in Greece on fake news, its characteristics, origin, and impact. This dissertation scopes to map the characteristics of fake news and misinformation in an EU country such as Greece, based on the findings of “Ellinika Hoaxes” a fact-checking platform that uses in combination professional fact-checkers and crowdsourcing strategies in collaboration with Facebook. The findings shape new perspectives on the nature of misinformation and fake news in Greece and focus on new communication and fact-checking models.

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Particle number-based trophic transfer of gold nanomaterials in an aquatic food chain

Nature Communications ◽

10.1038/s41467-021-21164-w ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Fazel Abdolahpur Monikh ◽

Latifeh Chupani ◽

Daniel Arenas-Lago ◽

Zhiling Guo ◽

Peng Zhang ◽

...

Keyword(s):

Physicochemical Properties ◽

Food Chain ◽

Particle Number ◽

Analytical Techniques ◽

Size And Shape ◽

Biological Fate ◽

Aquatic Food Chain ◽

Fit For Purpose ◽

Aquatic Food ◽

Gold Nanomaterials

AbstractAnalytical limitations considerably hinder our understanding of the impacts of the physicochemical properties of nanomaterials (NMs) on their biological fate in organisms. Here, using a fit-for-purpose analytical workflow, including dosing and emerging analytical techniques, NMs present in organisms are characterized and quantified across an aquatic food chain. The size and shape of gold (Au)-NMs are shown to control the number of Au-NMs attached to algae that were exposed to an equal initial concentration of 2.9 × 1011 particles mL−1. The Au-NMs undergo size/shape-dependent dissolution and agglomeration in the gut of the daphnids, which determines the size distribution of the NMs accumulated in fish. The biodistribution of NMs in fish tissues (intestine, liver, gills, and brain) also depends on NM size and shape, although the highest particle numbers per unit of mass are almost always present in the fish brain. The findings emphasize the importance of physicochemical properties of metallic NMs in their biotransformations and tropic transfers.

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A New Defect in Polyethylene Single Crystals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100070795 ◽

1973 ◽

Vol 31 ◽

pp. 70-71

Author(s):

E. L. Thomas ◽

S. L. Sass

Keyword(s):

Single Crystals ◽

Screw Dislocation ◽

Small Distance ◽

Dipole Model ◽

Dislocation Dipole ◽

Chain Folding ◽

Black And White ◽

Polymer Crystal ◽

Different Types

In polyethylene single crystals pairs of black and white lines spaced 700-3,000Å apart, parallel to the [100] and [010] directions, have been identified as microsector boundaries. A microsector is formed when the plane of chain folding changes over a small distance within a polymer crystal. In order for the different types of folds to accommodate at the boundary between the 2 fold domains, a staggering along the chain direction and a rotation of the chains in the plane of the boundary occurs. The black-white contrast from a microsector boundary can be explained in terms of these chain rotations. We demonstrate that microsectors can terminate within the crystal and interpret the observed terminal strain contrast in terms of a screw dislocation dipole model.

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Pinocytotic-Like Forms of Mitochondria From Rat Anterior Pituitary

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100100470 ◽

1968 ◽

Vol 26 ◽

pp. 146-147

Author(s):

Burton B. Silver

Keyword(s):

Electron Micrographs ◽

Conformational Changes ◽

Anterior Pituitary ◽

Dynamic State ◽

Surrounding Cell ◽

The Matrix ◽

The Moment ◽

Cell Medium ◽

Sectioned Tissue ◽

State Of Activity

Sectioned tissue rarely indicates evidence of what is probably a highly dynamic state of activity in mitochondria which have been reported to undergo a variety of movements such as streaming, divisions and coalescence. Recently, mitochondria from the rat anterior pituitary have been fixed in a variety of configurations which suggest that conformational changes were occurring at the moment of fixation. Pinocytotic-like vacuoles which may be taking in or expelling materials from the surrounding cell medium, appear to be forming in some of the mitochondria. In some cases, pores extend into the matrix of the mitochondria. In other forms, the remains of what seems to be pinched off vacuoles are evident in the mitochondrial interior. Dense materials, resembling secretory droplets, appear at the junction of the pores and the cytoplasm. The droplets are similar to the secretory materials commonly identified in electron micrographs of the anterior pituitary.

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Drug Induced Changes in Cell Organelles

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100100299 ◽

1968 ◽

Vol 26 ◽

pp. 110-111

Author(s):

Sarah A. Luse

Keyword(s):

Clinical Medicine ◽

Cell Organelles ◽

Riboflavin Deficiency ◽

Drug Induced ◽

New Era ◽

Health And Disease ◽

In The Beginning ◽

Cellular Pathology ◽

Induced Changes ◽

The Impact

In the mid-nineteenth century Virchow revolutionized pathology by introduction of the concept of “cellular pathology”. Today, a century later, this term has increasing significance in health and disease. We now are in the beginning of a new era in pathology, one which might well be termed “organelle pathology” or “subcellular pathology”. The impact of lysosomal diseases on clinical medicine exemplifies this role of pathology of organelles in elucidation of disease today.Another aspect of cell organelles of prime importance is their pathologic alteration by drugs, toxins, hormones and malnutrition. The sensitivity of cell organelles to minute alterations in their environment offers an accurate evaluation of the site of action of drugs in the study of both function and toxicity. Examples of mitochondrial lesions include the effect of DDD on the adrenal cortex, riboflavin deficiency on liver cells, elevated blood ammonia on the neuron and some 8-aminoquinolines on myocardium.

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Applications of Scanning Microscopy in Biomedical Research

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101517 ◽

1968 ◽

Vol 26 ◽

pp. 354-355

Author(s):

T. L. Hayes

Keyword(s):

Information Content ◽

Biomedical Research ◽

Biomedical Applications ◽

Three Dimensional ◽

Dental Enamel ◽

Resolving Power ◽

Whole Mount ◽

Two Parameters ◽

Content Information ◽

Sectioned Tissue

Biomedical applications of the scanning electron microscope (SEM) have increased in number quite rapidly over the last several years. Studies have been made of cells, whole mount tissue, sectioned tissue, particles, human chromosomes, microorganisms, dental enamel and skeletal material. Many of the advantages of using this instrument for such investigations come from its ability to produce images that are high in information content. Information about the chemical make-up of the specimen, its electrical properties and its three dimensional architecture all may be represented in such images. Since the biological system is distinctive in its chemistry and often spatially scaled to the resolving power of the SEM, these images are particularly useful in biomedical research.In any form of microscopy there are two parameters that together determine the usefulness of the image. One parameter is the size of the volume being studied or resolving power of the instrument and the other is the amount of information about this volume that is displayed in the image. Both parameters are important in describing the performance of a microscope. The light microscope image, for example, is rich in information content (chemical, spatial, living specimen, etc.) but is very limited in resolving power.

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The influence of confocal microscope design on imaging performance

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100146564 ◽

1993 ◽

Vol 51 ◽

pp. 144-145

Author(s):

C J R Sheppard

Keyword(s):

Image Quality ◽

Fluorescence Imaging ◽

Confocal Microscope ◽

Industrial Applications ◽

Three Dimensions ◽

Design Parameters ◽

Weak Signals ◽

Size And Shape ◽

Imaging Performance ◽

Fundamental Limitation

The confocal microscope is now widely used in both biomedical and industrial applications for imaging, in three dimensions, objects with appreciable depth. There are now a range of different microscopes on the market, which have adopted a variety of different designs. The aim of this paper is to explore the effects on imaging performance of design parameters including the method of scanning, the type of detector, and the size and shape of the confocal aperture.It is becoming apparent that there is no such thing as an ideal confocal microscope: all systems have limitations and the best compromise depends on what the microscope is used for and how it is used. The most important compromise at present is between image quality and speed of scanning, which is particularly apparent when imaging with very weak signals. If great speed is not of importance, then the fundamental limitation for fluorescence imaging is the detection of sufficient numbers of photons before the fluorochrome bleaches.

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