The excavation of a medieval ring-ditch enclosure at Hayknowes Farm, Annan, Dumfries and Galloway

2001 ◽  
Vol 23 (2) ◽  
pp. 119-139
Author(s):  
R. A. GREGORY ◽  
D. W. HALL ◽  
D. W. SHIMWELL
Keyword(s):  
Radiocarbon Dating ◽  
Structural Phase ◽  
Morphological Characteristics ◽  
Internal Structures

Excavation at a crop-mark site found close to Annan, Dumfries and Galloway, revealed evidence of a ring-ditch containing a number of intriguing internal structures. Initially this was presumed to be a prehistoric monument, but pottery and radiocarbon dating, unexpectedly, indicated that the main structural phase of the site falls between the 11th-13th centuries AD. This suggests that a degree of caution is required when interpreting crop-mark sites on morphological characteristics alone. Moreover this excavation makes clear that morphological interpretation can have a constraining influence on excavation strategy, so caution is required when designing fieldwork programmes.

Structural-phase and morphological characteristics of silver catalysts on modified ceramic supports for selective oxidation of alcohols

2013 ◽  
Vol 87 (3) ◽  
pp. 376-381 ◽  
Author(s):  
A. S. Blokhina ◽  
I. A. Kurzina ◽  
L. N. Chukhlomina ◽  
O. G. Vitushkina ◽  
A. I. Smirnov ◽  
...  
Keyword(s):  
Selective Oxidation ◽  
Structural Phase ◽  
Morphological Characteristics ◽  
Silver Catalysts ◽  
Oxidation Of Alcohols

Dinosaur and Crocodile Fossils from the Mesozoic of Portugal: Neutron Tomography and Synchrotron-Radiation Based Micro-Computed Tomography

2011 ◽  
Vol 1319 ◽  
Author(s):  
Rui M.S. Martins ◽  
Felix Beckmann ◽  
Rui Castanhinha ◽  
Octávio Mateus ◽  
Philipp Klaus Pranzas
Keyword(s):  
Computed Tomography ◽  
Synchrotron Radiation ◽  
Morphological Characteristics ◽  
Neutron Tomography ◽  
Micro Computed Tomography ◽  
Internal Structures ◽  
Neutron Facility ◽  
Non Destructive ◽  
Non Destructive Techniques ◽  
Paleontological Study

ABSTRACTPortugal is ranked within the 10 countries with the most dinosaur taxa and the Lourinhã Formation is known by the Late Jurassic findings of dinosaurs and other fossils. In many cases, studies of the external morphological characteristics of the fossils are not sufficient to extract all the information for a paleontological study and, thus, observations of internal structures, using non-destructive techniques, are required. The fossils studied in the present work belong to the Museum of Lourinhã. The access to the Geesthacht Neutron Facility in Germany allowed us to characterize a jaw of the dinosaur Baryonyx walkeri specimen and the jaw of a crocodile (possibly a Tomistomidae) by Neutron Tomography. The study allowed us to detect the presence of teeth inside the jaws and it provides valuable information about the development of its dental characteristics. Synchrotron radiation based micro-computed tomography studies on tiny samples have been performed at the beamline HARWI II operated by the Helmholtz-Zentrum Geesthacht at the storage ring DORIS III at the Deutsches Elektronen–Synchrotron DESY in Hamburg, Germany. The first data recorded for eggshells collected in the Lourinhã Formation is shown. It allowed us to visualize the morphology of the pores and their connectivity in the eggshells, providing information that is either exceedingly difficult or impossible to obtain by traditional methods based on section cutting.

scholarly journals Time calibrated morpho-molecular classification of Nassellaria (Radiolaria)

2018 ◽  
Author(s):  
Miguel M. Sandin ◽  
Loic Pillet ◽  
Tristan Biard ◽  
Camille Poirier ◽  
Estelle Bigeard ◽  
...  
Keyword(s):  
Fossil Record ◽  
Phylogenetic Analyses ◽  
Molecular Ecology ◽  
Morphological Characteristics ◽  
Molecular Classification ◽  
Marker Genes ◽  
Microscopy Imaging ◽  
Worldwide Distribution ◽  
Internal Structures

AbstractNassellaria are marine radiolarian protists belonging to the Rhizaria lineage. Their skeleton, made of opaline silica, exhibit an excellent fossil record, extremely valuable in micro-paleontological studies for paleo-environmental reconstruction. Yet, to date very little is known about the extant diversity and ecology of Nassellaria in contemporary oceans, and most of it is inferred from their fossil record. Here we present an integrative classification of Nassellaria based on taxonomical marker genes (18S and 28S ribosomal DNA) and morphological characteristics obtained by optical and scanning electron microscopy imaging. Our phylogenetic analyses distinguished 11 main morpho-molecular clades relying essentially on the overall morphology of the skeleton and not on internal structures as previously considered. Using fossil calibrated molecular clock we estimated the origin of Nassellaria among radiolarians primitive forms in the Devonian (ca. 420 Ma), that gave rise to living nassellarian groups in the Triassic (ca. 250 Ma), during the biggest diversification event over their evolutionary history. This morpho-molecular framework provides both a new morphological classification easier to identify under light microscopy and the basis for future molecular ecology surveys. Altogether, it brings a new standpoint to improve our scarce understanding of the ecology and worldwide distribution of extant nassellarians.

Excavations on the Lower Terrace, Site C, Tintagel Island 1990–94

1997 ◽  
Vol 77 ◽  
pp. 1-143 ◽  
Author(s):  
C.D. Morris ◽  
Rachel Harry
Keyword(s):  
Mathematical Modelling ◽  
Radiocarbon Dating ◽  
Clay Soil ◽  
Structural Phase ◽  
Environmental Sampling ◽  
Lower Terrace ◽  
Wide Range ◽  
Modelling Techniques ◽  
Terrace Site ◽  
Trees And Shrubs

This article reports excavations undertaken between 1990 and 1994 on a small cliff terrace, at Tintagel Island in Cornwall. This terrace (the Lower Terrace) lies below Site C (the Middle Terrace), where a building was excavated by Dr C.A.R. Radford in the 1930s. The remains uncovered on the Lower Terrace comprise several phases of ephemeral stone and turf structures with associated hearths, floor deposits and stakeholes. These are separated by periods of shillet (tiny flakes of slate in sandy clay soil) levelling. With the collapse of the last structure the terrace was buried by layers of scree and slate slip from the slope above. Artefact groups of fire-lighting stones, whetstones and worked flint and quartz were recovered predominantly from earlier phases, together with Romano-British Native pottery. Later phases mainly comprised sherds of Imported Mediterranean pottery (84 per cent of all finds) and slate disc pot lids. The results of an extensive programme of environmental sampling clarified that a wide range of probably locally growing trees and shrubs were exploited for fuel, as well as for wattles and larger posts and beams. Tiny burnt fragments of animal and some human bone were found scattered through a handful of deposits, but the material is probably residual. A programme of radiocarbon dating was possible with the availability of charcoal material from hearths and stakeholes. This programme, using innovative mathematical modelling techniques, produced three distinct date ranges of structural activity on the Lower Terrace: 395–460 cal AD for one of the earliest phases of hearths, floors and stakeholes pre-dating the occurrence of Imported pottery; 415–535 cal AD for a later structural phase with hearths and first occurrences of Imported and Native pottery together; and 560–670 cal AD for the latest and best surviving structure, with hearths, stakeholes and a large assemblage of Imported pottery.

scholarly journals Recent Advances in Nucleic Acid Modulation for Functional Nanozyme

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 638
Author(s):  
Xin Wang ◽  
Yuancong Xu ◽  
Nan Cheng ◽  
Xinxian Wang ◽  
Kunlun Huang ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Nucleic Acids ◽  
Energy Conversion ◽  
Self Assembly ◽  
Morphological Characteristics ◽  
Reversible Binding ◽  
Internal Structures ◽  
Functional Modulation ◽  
Conversion Technologies ◽  
Development Prospects

Nanozymes have the potential to replace natural enzymes, so they are widely used in energy conversion technologies such as biosensors and signal transduction (converting biological signals of a target into optical, electrical, or metabolic signals). The participation of nucleic acids leads nanozymes to produce richer interface effects and gives energy conversion events more attractive characteristics, creating what are called “functional nanozymes”. Since different nanozymes have different internal structures and external morphological characteristics, functional modulation needs to be compatible with these properties, and attention needs to be paid to the influence of nucleic acids on nanozyme activity. In this review, “functional nanozymes” are divided into three categories, (nanozyme precursor ion)/ (nucleic acid) self-assembly, nanozyme-nucleic acid irreversible binding, and nanozyme-nucleic acid reversible binding, and the effects of nucleic acids on modulation principles are summarized. Then, the latest developments of nucleic acid-modulated nanozymes are reviewed in terms of their use in energy conversion technology, and their conversion mechanisms are critically discussed. Finally, we outline the advantages and limitations of “functional nanozymes” and discuss the future development prospects and challenges in this field.

scholarly journals Mechanical and Microscopic Characteristics of Polyurethane-Based Pervious Pavement Composites

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4365
Author(s):  
Hongdong Cho ◽  
Hongsu Bae ◽  
Chanho Park ◽  
Hyeong Min Park ◽  
Seo-Eun Oh ◽  
...  
Keyword(s):  
Morphological Characteristics ◽  
Element Model ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
X Ray ◽  
Pavement Materials ◽  
Pervious Pavement ◽  
Brittle Behavior ◽  
Internal Structures ◽  
Ct Analysis

Conventional pervious pavement materials (PPM) that consist of cement and aggregate materials are known for poor durability due to their brittle behavior. Thus, to enhance the durability, we fabricated polymeric PPMs from durable and abundant polyurethane (PU) and undertook mechanical and microscopic characterizations. PU-based PPM samples with varying aggregate sizes were produced and examined to test their compressive strength and water permeability. Furthermore, X-ray micro-computed tomography (micro-CT) was implemented to analyze the samples’ pore and tortuosity characteristics. Through the micro-CT analysis, the morphological characteristics of PPM’s internal structures were identified and quantitively analyzed the correlations between the pore size distribution, connectivity, and tortuosity within the samples. Finally, the microstructures derived from micro-CT were generated as a finite element model and also numerically determined the stress distribution generated inside.

scholarly journals Mechanical and Microscopic Characteristics of Polyurethane-Based Pervious Pavement Composites

2021 ◽  
Author(s):  
Hongdong Cho ◽  
Hongsu Bae ◽  
Changho Park ◽  
Hyeong Min Park ◽  
Seo-Eun Oh ◽  
...  
Keyword(s):  
Morphological Characteristics ◽  
Element Model ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
X Ray ◽  
Pavement Materials ◽  
Pervious Pavement ◽  
Brittle Behavior ◽  
Internal Structures ◽  
Ct Analysis

Conventional pervious pavement materials (PPM) consist of cement and aggregate materials and are known for poor durability due to their brittle behavior. Herein, we fabricated polymeric PPMs from durable and abundant polyurethane (PU) to enhance the durability of the material and undertook mechanical and microscopic characterizations. PU-based PPM samples with varying aggregate sizes were produced and the compressive strength and water permeability of each were examined. The pore and tortuosity characteristics of the specimens were analyzed using X-ray micro-computed tomography (micro-CT). Through the micro-CT analysis, the morphological characteristics of the internal structures of PPM were identified and the correlations between the pore size distribution, connectivity, and tortuosity within the specimen were quantitatively analyzed. The microstructures derived from micro-CT were generated as a finite element model and the stress distribution generated inside was numerically determined.

Ultrastructure of Giant Mitochondria and Their Inclusions in Schwann Cells of Bovine Splenic Nerve

1974 ◽  
Vol 32 ◽  
pp. 194-195
Author(s):  
Å. Thureson-Klein
Keyword(s):  
Schwann Cells ◽  
Cell Organelles ◽  
Giant Mitochondria ◽  
Matrix Density ◽  
Physiological Conditions ◽  
Unmyelinated Axons ◽  
Internal Structures ◽  
Structural Abnormalities ◽  
Cytotoxic Compounds ◽  
Cell Components

Giant mitochondria of various shapes and with different internal structures and matrix density have been observed in a great number of tissues including nerves. In most instances, the presence of giant mitochondria has been associated with a known disease or with abnormal physiological conditions such as anoxia or exposure to cytotoxic compounds. In these cases degenerative changes occurred in other cell organelles and, therefore the giant mitochondria also were believed to be induced structural abnormalities.Schwann cells ensheating unmyelinated axons of bovine splenic nerve regularly contain giant mitochondria in addition to the conventional smaller type (Fig. 1). These nerves come from healthy inspected animals presumed not to have been exposed to noxious agents. As there are no drastic changes in the small mitochondria and because other cell components also appear reasonably well preserved, it is believed that the giant mitochondria are normally present jin vivo and have not formed as a post-mortem artifact.

Cell Wall Ultrastructure in Three Strains of a Cariogenic Streptococcus

1971 ◽  
Vol 29 ◽  
pp. 338-339
Author(s):  
M. J. Kramer ◽  
Alan L. Coykendall
Keyword(s):  
Cell Wall ◽  
Dental Caries ◽  
Streptococcus Mutans ◽  
Microscopic Study ◽  
Electron Microscopic Study ◽  
Genetic Heterogeneity ◽  
Morphological Characteristics ◽  
Electron Microscopic ◽  
Dna Reassociation ◽  
Wall Ultrastructure

During the almost 50 years since Streptococcus mutans was first suggested as a factor in the etiology of dental caries, a multitude of studies have confirmed the cariogenic potential of this organism. Streptococci have been isolated from human and animal caries on numerous occasions and, with few exceptions, they are not typable by the Lancefield technique but are relatively homogeneous in their biochemical reactions. An analysis of the guanine-cytosine (G-C) composition of the DNA from strains K-1-R, NCTC 10449, and FA-1 by one of us (ALC) revealed significant differences and DNA-DNA reassociation experiments indicated that genetic heterogeneity existed among the three strains. The present electron microscopic study had as its objective the elucidation of any distinguishing morphological characteristics which might further characterize the respective strains.

Mitochondria in Cardiomyopathy: Alterations in Size, Number and Internal Structures

1968 ◽  
Vol 26 ◽  
pp. 126-127
Author(s):  
George Hug ◽  
William K. Schubert
Keyword(s):  
Heart Failure ◽  
Biochemical Analysis ◽  
Left Ventricular ◽  
Size Number ◽  
Internal Structures ◽  
Left Ventricular Outflow ◽  
Chest X Ray ◽  
Myocardial Fibers ◽  
Muscle Biopsies ◽  
Needle Liver Biopsy

A white boy six months of age was hospitalized with respiratory distress and congestive heart failure. Control of the heart failure was achieved but marked cardiomegaly, moderate hepatomegaly, and minimal muscular weakness persisted.At birth a chest x-ray had been taken because of rapid breathing and jaundice and showed the heart to be of normal size. Clinical studies included: EKG which showed biventricular hypertrophy, needle liver biopsy which showed toxic hepatitis, and cardiac catheterization which showed no obstruction to left ventricular outflow. Liver and muscle biopsies revealed no biochemical or histological evidence of type II glycogexiosis (Pompe's disease). At thoracotomy, 14 milligrams of left ventricular muscle were removed. Total phosphorylase activity in the biopsy specimen was normal by biochemical analysis as was the degree of phosphorylase activation. By light microscopy, vacuoles and fine granules were seen in practically all myocardial fibers. The fibers were not hypertrophic. The endocardium was not thickened excluding endocardial fibroelastosis. Based on these findings, the diagnosis of idiopathic non-obstructive cardiomyopathy was made.

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