Studies on the life history and development ofProteocephalus percae(Müller) (Cestoda: Proteocephalidea)

1974 ◽  
Vol 48 (4) ◽  
pp. 269-281 ◽  
Author(s):  
R. Wootten
Keyword(s):  
Egg Production ◽  
Perca Fluviatilis ◽  
Intestinal Wall ◽  
Initial Growth ◽  
Field Observations ◽  
Rate Of Development ◽  
Second Stage ◽  
Mesocyclops Leuckarti ◽  
Different Temperatures ◽  
Two Stages

AbstractThe life-cycle of the cestodeProteocephalus percae(Müller), a parasite of the perchPerca fluviatilisL., involves two hosts and was studied both experimentally and by field observations in Hanningfield Reservoir, Essex. The hexacanth embryo is bilaterally symmetrical, with three pairs of hooks and paired glands. The copepodsCyclops (Eucyclops) agilis, C. (Mesocyclops) leuckarti and C. (Acantftocyclops) viridiswere infected experimentally withP. percaeeggs. The egg hatches in the intestine, the embryo penetrates the intestinal wall by means of its hooks and possibly by secretions from its paired glands, and the larva develops within the haemocoel. Development took 3–4 weeks at 14°C inC. viridis, but the rate of development varied at different temperatures and copepod species differed in their suitability as hosts forP. percaelarvae. The adult cestode showed a yearly cycle of occurrence and maturation in perch. Egg production occurred in the spring, after which adult worms were lost from the fish to be quickly replaced by juvenile worms of the succeeding generation. Increase in length of the adult cestode population occurred in two stages, a period of rapid initial growth commencing immediately after establishment in the perch, and a second stage closely associated with maturation of the worms.

Observations on the free-living stages of strongylid nematodes of the horse

Parasitology ◽  
1972 ◽  
Vol 64 (3) ◽  
pp. 461-477 ◽  
Author(s):  
C. P. Ogbourne
Keyword(s):  
Laboratory Experiments ◽  
Field Observations ◽  
Infective Stage ◽  
Free Living ◽  
Rate Of Development ◽  
Infective Larvae ◽  
Strongylus Vulgaris ◽  
Different Temperatures ◽  
Eggs And Larvae

Observations have been made on the development and survival of the free-living stages in faeces deposited out of doors at different times of year, and on the migration of infective larvae to the surrounding herbage. Laboratory experiments were performed to assist in the interpretation of the field observations. Studies were made on the rate of development to the infective stage in faeces kept at different temperatures. The rates at which eggs and larvae of Strongylus vulgaris, S edentatus, S. equinus and Trichonema nassatum developed on faecal-agar cultures at different temperatures were compared. Studies were also made on the effect of desiccation of faeces on the development and survival of the free-living stages. The results of these observations are discussed in relation to the development of herbage infestations on British pastures.

scholarly journals Studying of capacity of the inflamed intestinal wall to accumulate tienam preparation in experiment

2019 ◽  
Vol 86 (11-12) ◽  
pp. 72-77
Author(s):  
V. V. Nepomniashchyi
Keyword(s):  
Experimental Investigation ◽  
Body Mass ◽  
Intestinal Wall ◽  
Laboratory Animals ◽  
Mechanical Ileus ◽  
Second Stage ◽  
Highly Effective ◽  
Two Stages ◽  
Therapeutic Doses

Objective. Using experimental pattern of mechanical ileus, to study the capacity of nonchanged and inflamed intestine to accumulate a tienam preparation. Materials and methods. The experiment was conducted on 60 laboratory animals in two stages. On the first stage the content of tienam in the blood, parenchymatous organs and in the nonchanged intestinal wall was determined. On the second stage the content of the tienam components was determined in the blood, parenchymatous organs and in the wall of inflamed suprastenotic part of intestine. In both series the preparation was injected intravenously in accordance to scheme, calculated for the animals body mass. The quantity of tienam preparation in the investigated material was determined, using the method of a highly effective liquid chomatography. Results. The experimental investigation conducted have shown, that the tienam preparation components in nonoperated animals are accumulated in therapeutic doses in the blood, liver and kidneys. In the animals, in whom mechanical ileus was simulated, he tienam components were revealed only in parenchymatous organs and in the blood. In the inflamed intestinal wall the tienam components were not revealed even while injection of a dose, prevailing a middle therapeutic one  in 2.5 times. Conclusion. Imipenem and cilastatin, which are included into tienam preparation, while secondary injections in a dose, prevailing a middle therapeutic one  in 2.5 times, were not revealed in the wall of the inflamed intestine in experimental mechanical ileus.

Study on Dislocation Behaviors during PVT Growth of 4H-SiC

2019 ◽  
Vol 963 ◽  
pp. 64-67 ◽  
Author(s):  
Im Gyu Yeo ◽  
Tai Hee Eun ◽  
Jang Yul Kim ◽  
Seung Suk Lee ◽  
Han Seok Seo ◽  
...  
Keyword(s):  
Grown Crystal ◽  
Temperature Gradients ◽  
Initial Growth ◽  
Internal Temperature ◽  
Second Stage ◽  
Initial Stage ◽  
Basal Plane Dislocation ◽  
Two Stages ◽  
Surface Morphologies ◽  
Edge Dislocations

The generation and transformation of dislocations in 4H-SiC crystals grown by PVT were investigated. Experiments were carried out in two stages for more comprehensive observation on dislocation behaviors. For the first stage known as initial growth, we investigated mainly the seed and grown interface. The behavior and transition of the dislocations in grown crystal were observed along the length of the crystal at second stage. The formation of threading edge dislocations (TEDs) strongly depends on the surface morphologies related with internal temperature gradients during crystal growth. The basal plane dislocation (BPDs) and threading screw dislocation (TSDs) cause from the seed crystal and formed at the initial stage of growth were gradually decreased in number along the length of the crystal and under certain conditions such as distorted stresses, dislocations were converted into other types of dislocations.

scholarly journals Investigation of Decarburization Behaviour during the Sintering of Metal Injection Moulded 420 Stainless Steel

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 211
Author(s):  
Jia Lou ◽  
Muyao Liu ◽  
Hao He ◽  
Xinming Wang ◽  
Yimin Li ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Carbon Content ◽  
Content Distribution ◽  
Particle Surface ◽  
Second Stage ◽  
Surface Oxides ◽  
Centre Region ◽  
Different Temperatures ◽  
Powder Particles ◽  
Two Stages

The decarburization behaviour during the sintering of metal-injection-moulded 420 stainless steel was investigated. Particular attention has been paid to the decarburization mechanisms and carbon distribution of parts sintered at different temperatures. The results indicate that the loss of carbon content occurs mainly through the reduction of surface oxides of powder particles or reaction with the atmosphere. Depending on the densification level, the sintering decarburization is separated into two stages. Below 1200 °C, decarburization occurs at the powder particle surface. The surface oxides react with the amorphous carbon or residual organics to pose the metal surface. At this time, the carbon content distribution of the sintered body is similar to that of the as-debound sample. The reduction of surface oxides promotes sintering. At 1200 °C, the densification speed is higher in the centre region of the sample, where the interconnected pores close and the second stage of decarburization takes place. At temperatures above 1200 °C, carbon atoms in the inner layers must migrate to the surface to react with the atmosphere. The decarburization speed is reduced and the carbon content distribution of the as-sintered part is similar to that of the dense decarburized part.

The influence of Trypanites in the diagenesis of Devonian stromatoporoids

1988 ◽  
Vol 62 (01) ◽  
pp. 22-31 ◽  
Author(s):  
S. George Pemberton ◽  
Brian Jones ◽  
Gregory Edgecombe
Keyword(s):  
Complex Interaction ◽  
Growth Stages ◽  
Initial Growth ◽  
Third Generation ◽  
Fort Mcmurray ◽  
Second Stage ◽  
The Third ◽  
Profound Influence ◽  
Two Generations ◽  
Two Stages

Stromatoporoids from the Late Devonian (early Frasnian) Waterways Formation near Fort McMurray, Alberta, contain well preservedTrypanitesMägdefrau. The stromatoporoid heads are formed of an initial growth ofClathrocoilona inconstansStearn that is encased by a second stage growth ofTrupetostroma papulosumStearn. These two stages were separated by a period of no growth and erosion. The first two generations of boring penetrated the skeleton ofC. inconstanswhile the third generation borings penetrated bothC. inconstansandT. papulosum.The borings in the stromatoporoids are filled with light colored micrite, dark colored micrite, skeletal fragments, dolomite, non-ferroan calcite, and ferroan calcite. Analysis of the borings, the growth stages of the stromatoporoids, the boring fill, and the orientation of the geopetal fabrics indicates that the stromatoporoids were subjected to repeated cycles of growth-boring-filling and reorientation. This complex interaction of biologic and physical reworking had a profound influence on the diagenetic transformation of the stromatoporoid heads. This example clearly illustrates the role that biogenic agents can play in the production of diagenetic fabrics of hard carbonate substrates.

scholarly journals In vitro tests of dense hydroxyapatite materials

2009 ◽  
Vol 11 (1) ◽  
pp. 44-49 ◽  
Author(s):  
Agnieszka Sobczak ◽  
Anna Kida ◽  
Zygmunt Kowalski ◽  
Zbigniew Wzorek
Keyword(s):  
Ph Value ◽  
Calcium Content ◽  
In Vitro Tests ◽  
Distilled Water ◽  
Second Stage ◽  
Air Atmosphere ◽  
Different Temperatures ◽  
Main Component ◽  
Two Stages

In vitro tests of dense hydroxyapatite materials The paper presents the results of the calcining process of deproteinised and defatted bone pulp called bone sludge. The calcining process was performed in two stages. The first step of the calcining process was realized at the temperature of 600°C in a rotary kiln. In the second stage the obtained bone ashes were calcined at five different temperatures from 650°C to 950°C for 2 hours in a chamber kiln and in air atmosphere. The products of the calcining process were characterized by the XRD method. Calcium content was determined by titration whereas the contents of total phosphorus and acid-soluble phosphorus - by the spectrophotometric method. The X-ray analysis confirmed that hydroxyapatite is the main component of the calcining products. Calcium and phosphorus contents were kept at the level of 40% and 17.5%, respectively, which corresponded to the Ca/P ratio of not stechiometric hydroxyapatite. In vitro studies, in the simulated body fluid, Ringer liquid and distilled water were realised. The measurements of pH value of SBF and Ringer fluid were realized. Additionally electrical conductivity as well as pH for distilled water where conducted. The goal of these tests was to evaluate chemical durability of dense hydroxyapatite materials.

Получение наночастиц гидроксиапатита из естественных зубов

2021 ◽  
pp. 51-60
Author(s):  
Фатемех Мирджалили ◽  
Алиреза Навбазам ◽  
Нина Саманизаде
Keyword(s):  
Nano Particle ◽  
Hydroxyapatite Nanoparticles ◽  
Human Teeth ◽  
Second Stage ◽  
Phosphate Bonding ◽  
Stirring Time ◽  
Different Temperatures ◽  
Natural Teeth ◽  
Two Stages ◽  
Hydroxyapatite Phase

Hydroxyapatite is the most important bio ceramic, due to its structure and chemical composition which is similar to bone and teeth. In this study, hydroxyapatite nanoparticles were prepared from natural teeth in two stages. Initially, the nano HA particles was performed by whole tooth and in the second stage, the tooth was divided into dentine and root and HA nanoparticles were prepared from both portions of teeth. At first, freshly extracted human teeth both (whole tooth and dentine and root) were calcined at 850 °C and then, the effects of stirring time, surfactant and different temperatures were investigated. The XRD results confirmed that, the existence of hydroxyapatite phase in all samples. The phosphate bonding groups of PO43- at 1470 cm-1 and 669 cm-1 was confirmed by FTIR results. The FESEM results showed that, hydroxyapatite nano particle with the range of 29–46 nm at stirring time of 36 h with the addition of CTAB as a surfactant at 850 °C was obtained without agglomeration and good dispersion.

scholarly journals ATMOSPHERE OF SPACE IN STUDIO AIR PUTIH @BATUBATA, TANGERANG

2020 ◽  
Vol 4 (03) ◽  
pp. 288-305
Author(s):  
Rionaldi Rionaldi ; Yenny Gunawan
Keyword(s):  
Design Theory ◽  
Peripheral Vision ◽  
Field Observations ◽  
Architectural Space ◽  
Second Stage ◽  
Spatial Design ◽  
The Difference ◽  
Physical Elements ◽  
Two Stages ◽  
Stage Analysis

Abstract - The difference atmosphere between the dynamic and diverse on outer spaces, gradually becomes singular and static, is expected to be found in @Batubata. This is different from common architectural space which is only understood as hegemony of occulocentrism, that only focuses on visual studies. The study was conducted to scrutiny the formation of the atmosphere of space, by understanding the physical-spatial-material elements and unconscious peripheral sensations that experienced by the user subject. The atmosphere of space is abstract and intangible whose atmosphere can be felt through the medium of space in the built environment that is slow and encourages solitude. The study is done through two stages. The first stage is to describe the physical-spatial-material elements through elaboration of layering and transparency, dimensions and proportions, density and emptiness, and material based on Bert Bielefelt's spatial design theory. The second stage is to expose the peripheral vision felt by observers when experiencing spaces in @Batubata. Peripheral vision is felt simultaneously arising the emotions and imagination of its users. The elaboration was based on the theory presented by Juhanni Pallasmaa. The formation of atmosphere of the space is understood by the conclusions at these two stages. This is a study of the phenomenon that happens in architectural space. The method used is descriptivequalitative, data obtained from literature studies, field observations, interviews with architect planners and open questionnaires to the user subject. The study was conducted by reviewing the physical elements of spatial and material through initial observation, which was enriched by interviews and open questionnaires to space users. From the results of first phase analysis, it was concluded that the characters of the spaces were secluded, static and dense. In second stage analysis, the result was silent and calm space experience. From these two stages, it can be understood that @Batubata was able to provide an opportunity for visitors to feel solitude and slowness to experience the atmosphere through their peripheral vision. The subjects’ feelings and mood are always influenced the abstract formation of atmosphere of space. Key Words: @Batubata, physic-spatial-material, peripheral vision, atmosphere

The influence of Trypanites in the diagenesis of Devonian stromatoporoids

1988 ◽  
Vol 62 (1) ◽  
pp. 22-31 ◽  
Author(s):  
S. George Pemberton ◽  
Brian Jones ◽  
Gregory Edgecombe
Keyword(s):  
Complex Interaction ◽  
Growth Stages ◽  
Initial Growth ◽  
Third Generation ◽  
Fort Mcmurray ◽  
Second Stage ◽  
The Third ◽  
Profound Influence ◽  
Two Generations ◽  
Two Stages

Stromatoporoids from the Late Devonian (early Frasnian) Waterways Formation near Fort McMurray, Alberta, contain well preserved Trypanites Mägdefrau. The stromatoporoid heads are formed of an initial growth of Clathrocoilona inconstans Stearn that is encased by a second stage growth of Trupetostroma papulosum Stearn. These two stages were separated by a period of no growth and erosion. The first two generations of boring penetrated the skeleton of C. inconstans while the third generation borings penetrated both C. inconstans and T. papulosum. The borings in the stromatoporoids are filled with light colored micrite, dark colored micrite, skeletal fragments, dolomite, non-ferroan calcite, and ferroan calcite. Analysis of the borings, the growth stages of the stromatoporoids, the boring fill, and the orientation of the geopetal fabrics indicates that the stromatoporoids were subjected to repeated cycles of growth-boring-filling and reorientation. This complex interaction of biologic and physical reworking had a profound influence on the diagenetic transformation of the stromatoporoid heads. This example clearly illustrates the role that biogenic agents can play in the production of diagenetic fabrics of hard carbonate substrates.

Altered Fine Structure of B Lymphocytes Correlated with Defective Terminal Differentiation

1973 ◽  
Vol 31 ◽  
pp. 386-387
Author(s):  
Dale E. Bockman ◽  
L. Y. Frank Wu ◽  
Alexander R. Lawton ◽  
Max D. Cooper
Keyword(s):  
Immune Deficiency ◽  
B Lymphocytes ◽  
Plasma Cells ◽  
Present Report ◽  
Specific Antigen ◽  
Terminal Differentiation ◽  
Second Stage ◽  
Two Stages ◽  
Deficiency Diseases ◽  
Cell Line Generation

B-lymphocytes normally synthesize small amounts of immunoglobulin, some of which is incorporated into the cell membrane where it serves as receptor of antigen. These cells, on contact with specific antigen, proliferate and differentiate to plasma cells which synthesize and secrete large quantities of immunoglobulin. The two stages of differentiation of this cell line (generation of B-lymphocytes and antigen-driven maturation to plasma cells) are clearly separable during ontogeny and in some immune deficiency diseases. The present report describes morphologic aberrations of B-lymphocytes in two diseases in which second stage differentiation is defective.

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