scholarly journals EVIDENCE FOR A BLOOD-THYMUS BARRIER USING ELECTRON-OPAQUE TRACERS

1972 ◽  
Vol 136 (3) ◽  
pp. 466-498 ◽  
Author(s):  
Elio Raviola ◽  
Morris J. Karnovsky
Keyword(s):  
Capillary Endothelium ◽  
Time Intervals ◽  
Adult Mice ◽  
Strategic Location ◽  
Endothelial Junctions ◽  
Long Time ◽  
Intercellular Clefts ◽  
Cortical Capillaries ◽  
Reticular Cells ◽  
Colloidal Lanthanum

In order to verify the existence of a blood-thymus barrier to circulating macromolecules, the permeability of the vessels of the thymus was analyzed in young adult mice using electron opaque tracers of different molecular dimensions (horseradish peroxidase, cytochrome c, catalase, ferritin, colloidal lanthanum). Results show that although blood-borne macromolecules do penetrate the thymus, their parenchyma] distribution is limited to the medulla of the lobe by several factors: (a) the differential permeability of the various segments of the vascular tree; (b) the spatial segregation of these segments within the lobe; (c) the strategic location of parenchymal macrophages along the vessels. The cortex is exclusively supplied by capillaries, which have impermeable endothelial junctions. Although a small amount of tracer is transported by plasmalemmal vesicles through the capillary endothelium, this tracer is promptly sequestrated by macrophages stretched out in a continuous row along the cortical capillaries and it does not reach the intercellular clefts between cortical lymphocytes and reticular cells. The medulla contains all the leaky vessels, namely postcapillary venules and arterioles. Across the walls of the venules, large quantities of all injected tracers escape through the clefts between migrating lymphocytes and endothelial cells; also the arterioles have a small number of endothelial junctions which are permeable to peroxidase, but do not allow passage of tracers of higher molecular weight. The tracers released by the leaky vessels penetrate the intercellular clefts of the medulla, but they never reach the cortical parenchyma, even at long time intervals after the injection. Therefore, a blood-thymus barrier to circulating macromolecules does exist, but is limited to the cortex. Medullary lymphocytes are freely exposed to blood-borne substances.

scholarly journals Optimal Perturbations of an Oceanic Vortex Lens

Fluids ◽  
2018 ◽  
Vol 3 (3) ◽  
pp. 63 ◽  
Author(s):  
Thomas Meunier ◽  
Claire Ménesguen ◽  
Xavier Carton ◽  
Sylvie Le Gentil ◽  
Richard Schopp
Keyword(s):  
Normal Mode ◽  
Growth Rates ◽  
Time Interval ◽  
Time Intervals ◽  
Horizontal Structure ◽  
Azimuthal Wave ◽  
Wave Numbers ◽  
Non Linear ◽  
Long Time ◽  
Short Time

The stability properties of a vortex lens are studied in the quasi geostrophic (QG) framework using the generalized stability theory. Optimal perturbations are obtained using a tangent linear QG model and its adjoint. Their fine-scale spatial structures are studied in details. Growth rates of optimal perturbations are shown to be extremely sensitive to the time interval of optimization: The most unstable perturbations are found for time intervals of about 3 days, while the growth rates continuously decrease towards the most unstable normal mode, which is reached after about 170 days. The horizontal structure of the optimal perturbations consists of an intense counter-shear spiralling. It is also extremely sensitive to time interval: for short time intervals, the optimal perturbations are made of a broad spectrum of high azimuthal wave numbers. As the time interval increases, only low azimuthal wave numbers are found. The vertical structures of optimal perturbations exhibit strong layering associated with high vertical wave numbers whatever the time interval. However, the latter parameter plays an important role in the width of the vertical spectrum of the perturbation: short time interval perturbations have a narrow vertical spectrum while long time interval perturbations show a broad range of vertical scales. Optimal perturbations were set as initial perturbations of the vortex lens in a fully non linear QG model. It appears that for short time intervals, the perturbations decay after an initial transient growth, while for longer time intervals, the optimal perturbation keeps on growing, quickly leading to a non-linear regime or exciting lower azimuthal modes, consistent with normal mode instability. Very long time intervals simply behave like the most unstable normal mode. The possible impact of optimal perturbations on layering is also discussed.

Super-Fine Structure in the Critical Flow-Rate of Critical Flow Venturi Nozzles

2002 ◽  
Author(s):  
Masahiro Ishibashi
Keyword(s):  
Fine Structure ◽  
Steady State ◽  
Discharge Coefficient ◽  
Constant Pressure ◽  
Pressure Ratio ◽  
Critical Flow ◽  
Time Intervals ◽  
Critical Flow Rate ◽  
A Value ◽  
Long Time

It is shown that critical flow Venturi nozzles need time intervals, i.e., more than five hours, to achieve steady state conditions. During these intervals, the discharge coefficient varies gradually to reach a value inherent to the pressure ratio applied. When a nozzle is suddenly put in the critical condition, its discharge coefficient is trapped at a certain value then afterwards approaches gradually to the inherent value. Primary calibrations are considered to have measured the trapped discharge coefficient, whereas nozzles in applications, where a constant pressure ratio is applied for a long time, have a discharge coefficient inherent to the pressure ratio; inherent and trapped coefficients can differ by 0.03–0.04%.

Specific inhibition of response to purified protein antigens

1956 ◽  
Vol 146 (922) ◽  
pp. 18-33 ◽  
Keyword(s):  
Antibody Formation ◽  
The Body ◽  
Specific Inhibition ◽  
Protein Antigens ◽  
Bovine Albumin ◽  
Adult Mice ◽  
Immune Paralysis ◽  
Small Doses ◽  
Long Time ◽  
Stimulate Antibody

The injection of large doses of pneumococcus polysaccharides into adult mice fails to stimulate antibody formation and prevents subsequent small doses from stimulating antibody formation. This inhibition—termed immune paralysis (Felton 1949; Felton, Cameron & Prather 1941; Felton, Kauffmann, Prescott & Ottinger 1955) persists for at least 15 to 18 months. It is not possible to produce a similar effect with protein antigens. Dixon & Maurer (1953, I955 a,b ) injected very large quantities of bovine serum albumin into adult rabbits, 18 g/kg rabbit over a period of 6 weeks. Within 6 weeks of these injections four of the five animals produced antibody in response to injections of bovine albumin. It is not surprising that a long time elapsed before antibody could be detected, since during the persistence of antigen in the body, all antibody released would have combined with that vast excess of antigen.

PENERAPAN ESTETIKA VISUAL ARSITEKTUR MODEREN PADA REDESAIN BANGUNAN & FASAD HOTEL KOTA TEPIAN DI SAMARINDA

2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Nur Husniah Thamrin ◽  
Maulana Refindo Dhuhur
Keyword(s):  
Economic Potential ◽  
Architectural Style ◽  
Natural Lighting ◽  
Public Facilities ◽  
East Kalimantan ◽  
Building Facades ◽  
Strategic Location ◽  
Long Time ◽  
To Come ◽  
The City

ABSTRACTThe development of the city of Samarinda is increasing and is still sustainable for a long time, especially in terms of suppressing administrative areas. The city of Samarinda as a province of East Kalimantan still has economic potential to continue to grow, this is triggered by increasing population and economic growth in the city of Samarinda. Hotel Kota Tepian have been around for a long time around 1990, Hotel Kota Tepian are included in the class of 2 star hotels that have various facilities such as 25 rooms to stay with various types of superior, premium, and standard. Hotel Kota Tepian also provides facilities for meetings, restaurants and SPA.The advantages of the Hotel Kota Tepian are its strategic location and is located in the middle of the city close to public facilities, offices and shopping centers such as Segiri Market, Mall Plaza Mulia, and Lembuswana while the shortcomings and problems of the Hotel Kota Tepian are designing the City Edge Hotel with emphasis on building facades using a modern architectural style, then designing natural lighting and artificial redesign on the interior of the Hotel Kota Tepian. Therefore, Kota Tepian hotel really needs to be redesigned to restore the image of the hotel in terms of visual aesthetic facade so that it becomes an attraction for visitors to come and feel comfortable while Kota Tepian Hotel.Keywords: Hotel, Kota Tepian, Redesign, Building, Facade. ABSTRAKPerkembangan kota Samarinda semakin meningkat dan masih berkelanjutan dalam waktu yang lama, khususnya dalam hal penekanan wilayah administrasi. Kota Samarinda sebagai provinsi dari Kalimantan Timur masih memiliki potensi ekonomi untuk terus berkembang, hal ini dipicu oleh semakin meningkatnya pertumbuhan penduduk dan ekonomi di kota Samarinda.Hotel Kota Tepian telah berdiri sejak lama sekitar tahun 1990, Hotel Kota Tepian termasuk dalam kelas hotel berbintang 2 yang memiliki berbagai macam fasilitas seperti 25 kamar tempat menginap dengan berbagai tipe yaitu superior, premium, dan standart.Pada Hotel Kota Tepian juga menyediakan fasilitas untuk pertemuan, restorant, dan SPA. Kelebihan dari Hotel Kota Tepian adalah lokasi yang strategis dan terletak di tengah kota dekat dengan falitas umum, perkantoran dan pusat perbelanjaan seperti pasar segiri, mall plaza mulia, dan lembuswana sedangkan kekurangan dan menjadi permasalahan dan penekanan dari Hotel Kota Tepian yaitu meredesain Hotel Kota Tepian dengan penekanan pada fasad bangunan dengan memakai gaya arsitektur modern. Maka dari itu Hotel Kota Tepian sangat perlu untuk di redesain untuk mengembalikan citra hotel dari segi estetika visual fasad sehingga menjadi daya tarik bagi pengunjung untuk datang dan merasa nyaman saat berada di Hotel Kota Tepian.Kata Kunci: Hotel, Kota Tepian, Redesain, Fasad, Bangunan.

Histological and Ultrastructural Study of the «Cortico-medullary Perivenular Lymphoid Sheaths» of the Mouse Thymus

1967 ◽  
Vol 53 (3) ◽  
pp. 245-267 ◽  
Author(s):  
Luigi Mazzarella ◽  
Luciano Fiore-donati
Keyword(s):  
Basement Membrane ◽  
Light And Electron Microscopy ◽  
Blood Stream ◽  
Perivascular Space ◽  
Lymphoid Cells ◽  
Morphological Data ◽  
Mouse Thymus ◽  
Cortical Capillaries ◽  
Vascular Structures ◽  
Reticular Cells

The present study is concerned with morphological investigations on some special vascular structures of the mouse thymus pertinent to the problem of «cellular traffic» in this organ. Thymuses from 20 normal mice of C3Hf/Gs and C57BL strains, ranging in age from 30 to 50 days, were examined by both light and electron microscopy. At the cortico-medullary junction wide post-capillary venules are present, running parallel to the border between cortex and medulla. They receive at right angles narrow capillaries coming especially from the cortex. The wall of these venules is formed of flattened endothelium, its basement membrane and epithelial reticular cells arranged as adventitial cells. The basement membrane of the endothelium is more or less regularly split in two layers (the inner «vascular» layer and the outer «parenchymal» layer) thus delineating a perivascular space containing one or more rows of lymphoid cells. This space, which has on the whole the character of a cylindrical perivascular channel, accompanies the cortico-medullary venules, although not necessarily along their entire course, and it is recognizable even around the cortical capillaries draining into them. The two layers of the basement membrane are lined on the inner side by the laminar cytoplasm of epithelial reticular cells, often interconnected by desmosomes. The ultrastructural characteristics of the perivascular space do not support the hypothesis of its lymphatic nature, as maintained by other authors. Lymphocytes were found in the process of migrating through either the «parenchymal» or «vascular» layer of the basement membrane. Although the direction of migration cannot be determined by static pictures, some morphological data seem to suggest that lymphocytes, at the level of the cortico-medullary venules, move from the thymic parenchyma towards the perivascular space and from there into the circulating blood stream. It is suggested that the perivascular apparatus be termed «cortico-medullary perivenular lymphoid sheath».

Hydrostatic Retesting of Existing Pipelines

1984 ◽  
Vol 106 (3) ◽  
pp. 362-368
Author(s):  
J. F. Kiefner ◽  
T. P. Forte
Keyword(s):  
Growth Rate ◽  
Time To Failure ◽  
Operating Pressure ◽  
Pipe Material ◽  
Rate Data ◽  
Time Intervals ◽  
Large Pressure ◽  
Pressure Cycle ◽  
Long Time ◽  
Test Pressure

An analytical model is presented for predicting hydrostatic retest intervals in liquid pipelines which are subjected to frequent large pressure cycles. The model utilizes pressure cycle history, hydrostatic test history, and fatigue crack growth rate data for the pipe material to calculate time to failure for the largest possible defect which could have survived a previous hydrostatic test. An example problem is described which shows the value of maximizing the margin between test pressure and operating pressure in order to achieve long time intervals between tests.

Review Lecture - Long time-scale fluctuations in the evolution of the Earth

1981 ◽  
Vol 375 (1760) ◽  
pp. 1-41 ◽  
Keyword(s):  
Current Knowledge ◽  
Interstellar Matter ◽  
The Sun ◽  
Time Intervals ◽  
Interstellar Clouds ◽  
The Earth ◽  
The Galaxy ◽  
Long Time ◽  
Extended Review ◽  
Review Current

This lecture is an attempt to review current knowledge about certain terrestrial phenomena with the twofold purpose: ( a ) to discover the extent to which the behaviour of the Earth may be influenced by fluctuations in its astronomical environment, ( b ) to see if new knowledge of that environment may be gained from its influence on the Earth. Fluctuations in geomagnetism, climate, glaciation, biological extinctions, etc., are surveyed with special regard to datings and characteristic time-intervals; correlations between such fluctuations are discussed. Astronomical phenomena, within the Solar System and elsewhere in the Galaxy, that might cause terrestrial effects are reviewed. As regards astronomical effects on Earth: (i) There is a good case - not yet overwhelming - for the currently widely accepted view that fluctuations of glaciation within an ice-epoch result from changes of insolation accompanying fluctuations of the Earth’s motion relative to the Sun. Some evidence suggests that an ice-epoch may be triggered by variations of the astronomical environment encountered in the Sun’s motion relative to the Galaxy; but tectonic changes on Earth may be the main trigger. (ii) Impacts of planetesimals may be more important than hitherto recognized. Among astronomical results regarding the Sun, while the intensity of solar ‘activity’ is variable, terrestrial effects provide no confirmation that the Sun is a ‘variable star’. Regarding the Galaxy, impacting planetesimals may originate in interstellar clouds, and so provide on Earth samples of interstellar matter. Some unsolved problems emphasized by the review are listed; certain concepts that would call for consideration in any extended review are mentioned.

scholarly journals Design and interpretation of cell trajectory assays

2013 ◽  
Vol 10 (88) ◽  
pp. 20130630 ◽  
Author(s):  
Lucie G. Bowden ◽  
Matthew J. Simpson ◽  
Ruth E. Baker
Keyword(s):  
Cell Biology ◽  
Time Interval ◽  
Short Time Interval ◽  
Trajectory Data ◽  
Time Intervals ◽  
Different Types ◽  
Long Time ◽  
A Cell ◽  
Cell Trajectory ◽  
Short Time

Cell trajectory data are often reported in the experimental cell biology literature to distinguish between different types of cell migration. Unfortunately, there is no accepted protocol for designing or interpreting such experiments and this makes it difficult to quantitatively compare different published datasets and to understand how changes in experimental design influence our ability to interpret different experiments. Here, we use an individual-based mathematical model to simulate the key features of a cell trajectory experiment. This shows that our ability to correctly interpret trajectory data is extremely sensitive to the geometry and timing of the experiment, the degree of motility bias and the number of experimental replicates. We show that cell trajectory experiments produce data that are most reliable when the experiment is performed in a quasi-one-dimensional geometry with a large number of identically prepared experiments conducted over a relatively short time-interval rather than a few trajectories recorded over particularly long time-intervals.

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