scholarly journals X .— The morphology and evolution of the ambulacrum in the echinoidea Holectypoida

1920 ◽  
Vol 209 (360-371) ◽  
pp. 377-480 ◽  
Keyword(s):  
Relative Position ◽  
General Type ◽  
Vascular System ◽  
Early Stage ◽  
Larval Life ◽  
Large Area ◽  
Central Topic ◽  
Original Title ◽  
Vital Functions

During the course of the work upon which the following pages are primarily based, the need for an ever-increasing width of scope has continually arisen. In its original conception the paper was to treat of the structure of the Holectypoida alone. Gradually the inevitable comparisons extended their range, until in its final form the work deals more or less completely with the ambulacral structure of all the orders of the Echinoidea, and includes far more argument of a general type than was first intended. Nevertheless, the original title has been retained. As in a map designed to show the position of a town, a large area of the surrounding district must needs be included, so that the roads which lead to, from, or past the place can be distinguished; thus, too, the relative position of the Holectypoid ambulacrum in the morphogenesis of Echinoid ambulacra can only be appreciated by description of the homologous structures which preceded, succeeded, or diverged from it in the course of evolution. Thus the title, though far from comprehending all the matter subjoined to it, is apt, in that it indicates the central topic towards which all the others converge and contribute. In the study of the Echinoidea, the ambulacra and their associated structures have always been recognised as affording taxonomic evidence of great value. Not only do the "avenues” of pores attract attention, in denuded tests, by their distinctness and diversity, but the extensions of the water-vascular system to which they give passage are concerned with many vital functions. Ambulacral plates are among the first to appear during the metamorphosis of an Echinoid pluteus, and the development of ambulacral projections from the hydrocoel marks an early stage in larval life. An ambulacrum consists of an even number of columns of plates (usually two), each one of which is perforated for the transmission of a “tube-foot.’' There are thus two features, more or less interdependent, that are available for study in fossil forms—the plates and the pores. But it is only within the last five decades that any consistent attempts at an understanding of the plating-structure of the Echinoid corona have been made; and even now systematic writers most frequently limit their descriptions of the ambulacra to the nature of the pores and the distribution of the ornament.

scholarly journals Large-Area Resistive Strain Sensing Sheet for Structural Health Monitoring

Sensors ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 1386 ◽  
Author(s):  
Levent E. Aygun ◽  
Vivek Kumar ◽  
Campbell Weaver ◽  
Matthew Gerber ◽  
Sigurd Wagner ◽  
...  
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Printed Circuit Board ◽  
Early Stage ◽  
Field Tests ◽  
Circuit Board ◽  
Gauge Factor ◽  
Peak Strain ◽  
Large Area ◽  
Structural Health

Damage significantly influences response of a strain sensor only if it occurs in the proximity of the sensor. Thus, two-dimensional (2D) sensing sheets covering large areas offer reliable early-stage damage detection for structural health monitoring (SHM) applications. This paper presents a scalable sensing sheet design consisting of a dense array of thin-film resistive strain sensors. The sensing sheet is fabricated using flexible printed circuit board (Flex-PCB) manufacturing process which enables low-cost and high-volume sensors that can cover large areas. The lab tests on an aluminum beam showed the sheet has a gauge factor of 2.1 and has a low drift of 1.5 μ ϵ / d a y . The field test on a pedestrian bridge showed the sheet is sensitive enough to track strain induced by the bridge’s temperature variations. The strain measured by the sheet had a root-mean-square (RMS) error of 7 μ ϵ r m s compared to a reference strain on the surface, extrapolated from fiber-optic sensors embedded within the bridge structure. The field tests on an existing crack showed that the sensing sheet can track the early-stage damage growth, where it sensed 600 μ ϵ peak strain, whereas the nearby sensors on a damage-free surface did not observe significant strain change.

Stability Test Of 4 Ft2 Triple-Junction a-Si Alloy PV Production Modules

1994 ◽  
Vol 336 ◽  
Author(s):  
X. Deng ◽  
M. Izu ◽  
K. L. Narasimhan ◽  
S. R. Ovshinsky
Keyword(s):  
Triple Junction ◽  
Early Stage ◽  
Large Area ◽  
Roll To Roll ◽  
Manufacturing Line ◽  
Pv Modules ◽  
Stable Module ◽  
Module Efficiency ◽  
Sun Light ◽  
Made In

ABSTRACTWe report results of stability tests of 4 ft2 triple-junction a-Si alloy photovoltaic (PV) Modules. These Modules were produced in ECD's 2 Megawatt (MW) continuous, roll-to-roll PV Manufacturing line during the early stage of optimization. The stable module efficiency after 600 hours of 1 sun light soaking at approximately 50°C under load, is 8%. This is the highest stable efficiency for large area (≥4 ft2) a-Si alloy PV Modules Made in a production line.

scholarly journals Vascular Involvement in Rheumatoid Arthritis

2020 ◽  
Author(s):  
Alexandru Caraba ◽  
Stela Iurciuc ◽  
Mircea Iurciuc
Keyword(s):  
Rheumatoid Arthritis ◽  
Vascular System ◽  
Carotid Artery Disease ◽  
Early Stage ◽  
Macrovascular Disease ◽  
Vascular Involvement ◽  
Inflammatory Rheumatic Diseases ◽  
Artery Disease ◽  
The One ◽  
Peripheral Arterial

Rheumatoid arthritis (RA) represents the one of the most common inflammatory rheumatic diseases, which generates disability and significantly reduces the quality of life. RA can affect the vascular system, in addition to joint involvement. Vascular involvement increases the morbidity and mortality among these patients. Macrovascular disease, related to accelerated atherosclerosis, has a high prevalence among RA patients, in the form of carotid artery disease, ischemic heart disease, and peripheral arterial obstructive disease. Microvascular disease, studied in recent years by means of nailfold capillaroscopy, is present even in the early stage of RA evolution. Rheumatoid vasculitis can occur in severe forms of RA.

Host-pathogen relationship in tobacco plants with stems infected by Peronospora tabacina Adam

1960 ◽  
Vol 11 (1) ◽  
pp. 16 ◽  
Author(s):  
M Mandryk
Keyword(s):  
Secondary Xylem ◽  
Vascular System ◽  
Early Stage ◽  
Infected Leaf ◽  
Flowering Stage ◽  
Peronospora Tabacina ◽  
Axillary Shoots ◽  
Daily Temperature Range ◽  
Stem Infection ◽  
Nicotiana Tabacum L

Stem infection of tobacco (Nicotiana tabacum L. cv. Virginia Gold) with Peronospora tabacina Adam was established and its development studied. Mycelium of the pathogen spread from parenchyma tissue of the infected leaf blade into the vascular system of midrib and petiole and thence into the stem. In small seedlings mycelium was usually associated with all tissues and often killed the plant. In plants at the flowering stage necrosis was chiefly confined to the periphery of secondary xylem, the cambium, and the inner part of the external phloem region. As xylem aged it acted as a barrier to the spread of mycelium from external to internal phloem and to the pith. Cortex was not penetrated readily by the pathogen. When the pathogen became established in the cambium region of the stem at an early stage of plant growth, development of xylem was often inhibited. Such plants, when full grown, were brittle at the base and snapped off readily. Development of the pathogen in the stem was favoured by high humidity but was arrested by exposing the plants to benzol vapour, or to a daily temperature range of 75-105°F when humidity was not higher than 70 per cent. High temperature during the day followed by low temperature at night did not prevent spread of the pathogen from the leaves into the stem. Mycelium sometimes spread from infected stems into new axillary shoots with subsequent sporulation on leaves.

Entrainment Defects

2019 ◽  
Author(s):  
J. Campbell
Keyword(s):  
Liquid Metals ◽  
Early Stage ◽  
Surface Film ◽  
New Technology ◽  
Superplastic Forming ◽  
Hot Tearing ◽  
Surface Films ◽  
Large Area ◽  
Large Populations ◽  
Metallurgical Defect

Most metals start their lives in the liquid state, and are subjected to various transfers involving pouring or other types of surface turbulence. These actions entrain (fold in) the surface film to create entrainment defects. These are principally (a) bubbles that in turn create bubble trails; (b) bifilms; doubled over surface films, that act as cracklike defects; and (c) sundry entrained debris, collectively known as exogenous inclusions. The bifilm is the subject of this perspective. It appears to be a common, but serious and almost overlooked metallurgical defect. Analysis of bifilms provides a simple, powerful and elegant concept based on an enduring legacy from turbulence during the pouring of liquid metals. Usually large populations of bifilms are introduced into metals at an early stage of their production. In general their presence has been unsuspected because although they can have large area, they can often be only nanometres thick and not easily detected by conventional non-destructive techniques. The populations of cracks in suspension in liquid metal explains many otherwise inexplicable features of cast products such as porosity, hot tearing, the morphologies of second phases, and impaired reliability of mechanical properties. The fundamental difference between such entrained defects (associated with a macroscopic unbonded interface) and defects and inclusions grown in the melt is seen to be of central significance for the failures of metals by mechanical or corrosion type mechanisms. For wrought products the continued presence of bifilms, now usually extended and elongated and mainly occupying grain boundaries, appears to offer explanations for many metallurgical phenomena. Bifilms are likely to influence the development of texture, and are the most likely source for many types of failure in the solid state. Thus the limitations to superplastic forming, cavitation in tertiary creep, pitting corrosion of various types and stress corrosion cracking are likely to be profoundly affected by bifilms. Although the effects of bifilms can be reduced by expensive post-casting operations such as hipping or working, the major future potential lies in techniques for their avoidance. Some casting operations are already taking some first steps in new technology for their avoidance, and benefiting technically and commercially.

II. On the aquiferous and oviductal systems in the lamelli-branchiate mollusks

1859 ◽  
Vol 9 ◽  
pp. 633-634
Keyword(s):  
Relative Position ◽  
Vascular System ◽  
Great Distance ◽  
The Body ◽  
Lower Segment ◽  
Visceral Mass ◽  
Intestinal Tube ◽  
The Way

In this paper the authors bring forward two views as to the anatomy of the Lamellibranchiata. 1. The first part of the communication is devoted to an examination of the commonly-received opinion as to the outlet of the ovarian system, and arguments are brought forward to show that the orifices usually supposed to discharge this office are in reality the exhalant orifices of a water-vascular system. The positive arguments drawn from the way in which fine injections thrown in by these orifices distribute themselves throughout the visceral mass, and from the relative position of orifices acknowledged to belong to a water-vascular system in other mollusks, are confirmed by a consideration of the improbability attaching to the old view, which regarded as oviducts in mollusca two canals, which lying one on either side of the body, yet communicate freely with each other at no great distance from their termination, and which lie far away from the lower segment of the intestinal tube. The inhalant aquiferous orifices are considered to be indicated by a belt of parasitic animals impacted in the foot tissue, as represented in one of the figures.

scholarly journals The bronchial vascular system in the dog

1931 ◽  
Vol 109 (762) ◽  
pp. 214-228 ◽  
Keyword(s):  
Vascular System ◽  
Early Stage ◽  
Preliminary Investigation ◽  
Systemic Circulation ◽  
Bronchial Tree ◽  
Bronchial Arteries ◽  
Arterial Blood ◽  
Two Systems ◽  
Chief Interest ◽  
The Moment

The distribution of the bronchial arteries (the vasa nutritia of Reisseissen) within the lung has been investigated by many anatomists but, beyond our knowledge that they are nutritional vessels to the bronchial tree (Reisseissen and Sömmering, 1808; Reisseissen, 1808, 1822 ; Luschka, 1863; Königstein, 1903), little is known of their significance for the maintenance of the normal functions of the lungs. At the moment their chief interest lies in the number of reports describing the changes in the bronchial blood vessels resulting from interference with the pulmonary vascular system and from lesions in the lungs. Two years ago Professor E. B. Verney and one of us (I. de B. D.) were conducting experiments in this laboratory which involved the separation of the pulmonary from the systemic circulation in the dog, the two systems being perfused by separate pumps. In one experiment it appeared that blood was being transferred from the aorta to the left auricle through the bronchial vascular system. It became desirable, therefore, to inquire into the conditions which govern the bronchial blood supply. At an early stage in this inquiry it was evident that, owing to the variations in the origin of the bronchial arteries, a study of the gross and minute anatomy of the bronchial vascular system in each perfusion experiment would be necessary if anything approaching a correct interpretation of our results was to be expected. As a preliminary investigation to our perfusion experiments, we have examined the bronchial vascular system in a number of animals and the results form the subject of this paper. In it are also incorporated the anatomical findings on the perfused lungs used for physiological investigations. We have concentrated our efforts on two main issues: the first, the arrangement of the bronchial arteries and veins with a view to setting up apparatus for perfusion of the bronchial arteries and the collection of the blood from the bronchial veins ; the second, an enquiry into possible arterial and venous communications between the bronchial and pulmonary vascular systems. It is clear that if arterial anastomotic channels exist between the two systems it will not be possible to separate completely the arterial blood of each.

scholarly journals Ethanol combined with coil embolisation for the treatment of arteriovenous malformations in a patient with Parkes Weber syndrome

2020 ◽  
Vol 102 (3) ◽  
pp. e54-e56
Author(s):  
Q Zhao ◽  
Lian Liu ◽  
Z Liao ◽  
Y Pan ◽  
Jingyan Liu ◽  
...  
Keyword(s):  
Arteriovenous Malformations ◽  
Vascular System ◽  
Early Stage ◽  
Therapeutic Option ◽  
Coil Embolisation ◽  
Weber Syndrome ◽  
Congenital Condition ◽  
Initial Procedure ◽  
Life Threatening

Parkes Weber syndrome is a rare congenital condition of the vascular system with severe symptoms and life-threatening complications. The challenge is to manage the arteriovenous malformations, and there is no consensus on optimal treatment. We report the case of an 18-year-old woman with Parkes Weber syndrome who was treated with ethanol combined with coil embolisation at an early stage. After two sessions of embolisation, a significant devascularisation was achieved. No sign of recurrence was observed two years after the initial procedure. The patient’s symptoms and signs were greatly relieved during the follow-up period. This case raises awareness of Parkes Weber syndrome and highlights the importance of timely intervention, as well as offering a promising therapeutic option for this condition.

scholarly journals A CDC42 Homologue in Claviceps purpurea Is Involved in Vegetative Differentiation and Is Essential for Pathogenicity

2005 ◽  
Vol 4 (7) ◽  
pp. 1228-1238 ◽  
Author(s):  
Jan Scheffer ◽  
Changbin Chen ◽  
Patrick Heidrich ◽  
Martin B. Dickman ◽  
Paul Tudzynski
Keyword(s):  
Vascular System ◽  
Early Stage ◽  
Ovarian Tissue ◽  
Wild Strain ◽  
Extended Period ◽  
Small Gtpase ◽  
Dominant Negative ◽  
Claviceps Purpurea ◽  
Cytoskeleton Organization ◽  
Colletotrichum Trifolii

ABSTRACT Claviceps purpurea, a biotrophic pathogen of cereals, has developed a unique pathogenic strategy including an extended period of unbranched directed growth in the host's style and ovarian tissue to tap the vascular system. Since the small GTPase Cdc42 has been shown to be involved in cytoskeleton organization and polarity in other fungi, we investigated the role of Cdc42 in the development and pathogenicity of C. purpurea. Expression of heterologous dominant-active (DA) and dominant-negative (DN) alleles of Colletotrichum trifolii in a wild strain of C. purpurea had significant impact on vegetative differentiation: whereas DA Ctcdc42 resulted in loss of conidiation and in aberrant cell shape, expression of DN Ctcdc42 stimulated branching and conidiation. Deletion of the endogenous Cpcdc42 gene was not lethal but led to a phenotype comparable to that of DN Ctcdc42 transformants. ΔCpcdc42 mutants were nonpathogenic; i.e., they induced no disease symptoms. Cytological analysis (light microscopy and electron microscopy) revealed that the mutants can penetrate and invade the stylar tissue. However, invasive growth was arrested in an early stage, presumably induced by plant defense reactions (necrosis or increased production of reactive oxygen species), which were never observed in wild-type infection. The data show a significant impact of Cpcdc42 on vegetative differentiation and pathogenicity in C. purpurea.

scholarly journals Computed Tomography Angiography Evaluation of Peripheral Arterial Disease and Correlation with Colour Doppler

2020 ◽  
Vol 8 (2) ◽  
pp. 73-79
Author(s):  
M. Balaji Vara Prasad ◽  
Srinadh Boppana ◽  
Mounika Reddy ◽  
Nainika Juvvadi ◽  
Rajeshwari ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Peripheral Arterial Disease ◽  
Computed Tomography Angiography ◽  
Vascular System ◽  
Early Stage ◽  
Signs And Symptoms ◽  
Arterial Disease ◽  
Colour Doppler ◽  
Peripheral Arterial ◽  
Sensitivity Specificity

Background: Peripheral Arterial Disease Is a Major Problem Among the Population of Those 55 Years and Older. MDCT is a Non-Invasive Method of Visualization of Vascular System. It Affords More Widespread Vascular Screening, Allowing Diagnosis to be Made at an Early Stage. The objective is to Assess the Role of Multidetector Computed Tomography Angiography in Peripheral Arterial Disease of Lower Extremities. Subjects & Methods: A Prospective Study of 35 Patients with Signs and Symptoms of PVD, Were Subjected to Colour Doppler Ultrasonography and MDCT Examination Between a Period of 1st August 2018 to 31st May 2019. Results: Our Study Shows a Very Good Sensitivity, Specificity, PPV, NPV and Accuracy of Doppler in Assessing the Soft Plaque (82%, 100%, 100%, 97%, 97% Respectively) & in Evaluation of Stenosis Like <50% Stenosis (100%, 99%, 85%, 100% & 99% Respectively), 50-99% Stenosis (100%, 99%, 96%. 100% & 99.8% Respectively), & Occlusion (84%, 100%. 100%, 98% & 98% Respectively). The Only Parameter Which Showed Poor Result Was in Evaluation of Calcified Plaque. Conclusion: Our Study Shows that Both Colour Doppler & MDCT Can Be Complimentary in Lower Limb Arterial Disease Evaluation.

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