scholarly journals LIPOPROTEIN GRANULES IN THE CORTICAL COLLECTING TUBULES OF MOUSE KIDNEY

1961 ◽  
Vol 9 (1) ◽  
pp. 157-170 ◽  
Author(s):  
Fritz Miller
Keyword(s):  
Mouse Kidney ◽  
Physiological Significance ◽  
Square Lattice ◽  
Dark Cells ◽  
Lipoprotein Granules ◽  
Histochemical Tests ◽  
The Mean ◽  
Collecting Tubules ◽  
Center Distance

The light and, to a lesser extent, the dark cells of the cortical collecting tubules in mouse kidney contain a great number of granules which according to histochemical tests are composed of phospholipids and proteins. These granules are bounded by a triple-layered membrane measuring approximately 75 A across, and contain one or several crystals with a hexagonal or square lattice. These crystals are built up of rod-shaped units, which appear dense after osmium fixation, measure about 48 A in diameter, and are separated by a light interspace of similar dimensions. The mean center-to-center distance of the rods is about 96 A. The structure is explained as a lipoprotein crystallized within a membrane-bounded vacuole. No relationship between these granules and mitochondria was found. The physiological significance of the granules remains unknown.

SUPERCONDUCTING CLASSES IN THE EXTENDED HUBBARD MODEL

1996 ◽  
Vol 10 (12) ◽  
pp. 1397-1423 ◽  
Author(s):  
MASA-AKI OZAKI ◽  
EIJI MIYAI ◽  
TOMOAKI KONISHI ◽  
KAORU HANAFUSA
Keyword(s):  
Hubbard Model ◽  
Nearest Neighbor ◽  
Mean Field ◽  
Square Lattice ◽  
Extended Hubbard Model ◽  
S Wave ◽  
Ferromagnetic Order ◽  
Numerical Studies ◽  
The Mean

This paper describes group theoretical classification of superconducting states (SC) in the extended Hubbard model with on-site repulsion (U), nearest neighbor attraction (V) and nearest neighbour exchange interaction (J) on the two-dimensional square lattice using the mean field approach. By decomposing the pairing interaction into irreducible parts; A1g, B1g and Eu of D4h point symmetry, we have derived two singlet SCs (s-wave and d-wave) from A1g and B1g, eight triplet SCs from Eu. The first three types of triplet SC have pairing by electrons with antiparallel spin, the second two types have pairing by electrons with equal spin and the last three types are non-unitary and have pairing by only up-spin electrons. We showed that three non-unitary states have to be accompanied with a ferromagnetic order from the structure of the maximal little groups. We performed numerical studies for these SCs. For parameters and electron density favorable for the ferromagnetic order, a non-unitary SC coexistent with ferromagnetism is most stable.

scholarly journals DYNAMICAL MODEL FOR VIRUS SPREAD

Fractals ◽  
1996 ◽  
Vol 04 (02) ◽  
pp. 113-122 ◽  
Author(s):  
G. CAMELO-NETO ◽  
S. COUTINHO
Keyword(s):  
Steady State ◽  
Mean Field ◽  
Field Approximation ◽  
Square Lattice ◽  
Mean Field Approximation ◽  
Model Parameters ◽  
Viral Spread ◽  
Infected Cells ◽  
The Mean ◽  
Density Population

The steady state properties of the mean density population of infected cells in a viral spread is simulated by a general forest like cellular automaton model with two distinct populations of cells (permissive and resistant ones) and studied in the framework of the mean field approximation. Stochastic dynamical ingredients are introduced into this model to mimic cells regeneration (with probability p) and to consider infection processes by other means than contiguity (with probability f). Simulations are carried out on a L×L square lattice taking into consideration the eighth first neighbors. The mean density population of infected cells (Di) is measured as a function of the regeneration probability p, and analyzed for small values of the ratio f/p and for distinct degrees of cell resistance. The results obtained by a mean field like approach recovers the simulations results. The role of the resistant parameter R (R≥2) on the steady state properties, is investigated and discussed in comparison with the R=1 monocell case which corresponds to the self organized critical forest model. The fractal dimension of the dead cells ulcers contours was also estimated and analyzed as a function of the model parameters.

scholarly journals A Size-Perimeter Discrete Growth Model for Percolation Clusters

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Bendegúz Dezső Bak ◽  
Tamás Kalmár-Nagy
Keyword(s):  
Growth Model ◽  
Branching Process ◽  
Growth Models ◽  
Square Lattice ◽  
Cluster Growth ◽  
Invasion Percolation ◽  
Percolation Clusters ◽  
Proposed Model ◽  
Wide Range ◽  
The Mean

Cluster growth models are utilized for a wide range of scientific and engineering applications, including modeling epidemics and the dynamics of liquid propagation in porous media. Invasion percolation is a stochastic branching process in which a network of sites is getting occupied that leads to the formation of clusters (group of interconnected, occupied sites). The occupation of sites is governed by their resistance distribution; the invasion annexes the sites with the least resistance. An iterative cluster growth model is considered for computing the expected size and perimeter of the growing cluster. A necessary ingredient of the model is the description of the mean perimeter as the function of the cluster size. We propose such a relationship for the site square lattice. The proposed model exhibits (by design) the expected phase transition of percolation models, i.e., it diverges at the percolation threshold p c . We describe an application for the porosimetry percolation model. The calculations of the cluster growth model compare well with simulation results.

scholarly journals Crystal fields induced compensation temperatures in a decorated square lattice

2021 ◽  
Author(s):  
HADEY MOHAMAD
Keyword(s):  
Mean Field Theory ◽  
Mean Field ◽  
Square Lattice ◽  
Present System ◽  
Long Range Order ◽  
Two Dimensional ◽  
Crystal Fields ◽  
Crystalline Anisotropy ◽  
The Mean ◽  
Magnetization Behavior

A two-sublattice decorated Blume-Capel ferrimagnet has been investigated using the mean field theory. Interesting behaviors of long-range order are obtained depending on particular magnitudes of magnetocrystalline anisotropies for both sublattices sites. Distinguishable features have been discovered in two-dimensional decorated lattice consisting of spin-5/2 and decorating spin-7/2 ions on the bonds. It is found the present system shows two ferrimagnetic compensation temperatures. However, one compensation temperature for different or fixed values of decorated magnetic anisotropies with the values of J1=-0.5 , J2=-1.0 , or with J1=-1.0 , J2=-0.5, has been induced, respectively. The magnetization behavior in the (M,DB/IJ2I) space has not already been considered showing the crystalline anisotropy dependence of total magnetization remanences. Besides, the variations of net magnetizations versus the decorated crystal fields, i.e., in the(M,DA/IJ2I) space, have been done, with J1=-0.5, J2=-1.0 , for various values of T=2.0, 2.5,3.0 , respectively.

scholarly journals Foliar Micromorphology and Histochemical Localization of Specific Metabolites in the Leaves of Celosia argentea L.

2019 ◽  
Vol 47 (4) ◽  
pp. 1128-1135
Author(s):  
Oluwafunmilayo Dorcas ADEGBAJU ◽  
Gloria Aderonke OTUNOLA ◽  
Anthony Jide AFOLAYAN
Keyword(s):  
Glandular Trichomes ◽  
Major Elements ◽  
Digital Object Identifier ◽  
Abaxial Surface ◽  
X Ray ◽  
Sodium Calcium ◽  
Celosia Argentea ◽  
Histochemical Tests ◽  
The Mean ◽  
Information Database

Celosia argentea is an essential vegetable that is cultivated in the western part of Africa. This species has a growing reputation for its role in alleviating nutritional challenges and has found great application as herb of therapeutic importance in many regions of the world. This study investigated the foliar micromorphology and the histochemistry of Celosia argentea. Scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectrometry and staining agents were used to evaluate the micromorphology of the plant. The result revealed sunken amphistomatic stomata distribution on both surfaces of the leaf. Anomocytic and anisocytic stomata complexes were also observed on both epidermal surfaces. A definitive protuberance was observed on the polar end of the adaxial stomata. Stomata apparatus was ellipsoidal with a mean length of 19.60 ± 0.56 µm, while the mean stomata densities on the adaxial and abaxial surfaces were 83.5 ± 2.12 mm‑2 and 194.18 ± 3.70 mm‑2 respectively. Trichomes (with a length of 100.94 ± 9.44 µm) were sparsely distributed on both surfaces; glandular trichomes were observed only on the abaxial surface. The EDX spectrometry revealed the presence of iron, oxygen, sodium, calcium, potassium and sulphur as the major elements on the leaf, while histochemical tests revealed the presence of polyphenols, starch and lipids. Our results could be used to support and validate the information database on the anatomy of Celosia argentea.   ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 4, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********

V2-like vasopressin receptor mobilizes intracellular Ca2+ in rat medullary collecting tubules

1993 ◽  
Vol 265 (1) ◽  
pp. F35-F45 ◽  
Author(s):  
A. Champigneulle ◽  
E. Siga ◽  
G. Vassent ◽  
M. Imbert-Teboul
Keyword(s):  
Intracellular Calcium ◽  
Calcium Concentration ◽  
Free Calcium ◽  
Cytosolic Free Calcium ◽  
Free Calcium Concentration ◽  
Cytosolic Free Calcium Concentration ◽  
The Mean ◽  
V2 Antagonist ◽  
Collecting Tubules ◽  
Calcium Pool

Cytosolic free calcium concentration ([Ca2+]i) was measured in single microdissected rat medullary collecting tubules [outer (OMCD) and inner (IMCD)] to identify receptors involved in vasopressin (AVP)-induced [Ca2+]i increases. In both segments, [Phe2,Orn8]vasotocin ([Phe2,Orn8]VT), a specific V1 agonist, as well as the V2 agonist 1-desamino-8-D-AVP (dDAVP) triggered [Ca2+]i variations. In OMCD, the mean response to 10 nM AVP roughly corresponded to the sum of V1 and V2 agonists effects. In IMCD, dDAVP (10 nM) alone reproduced the calcium response to AVP (delta[Ca2+]i = 243 +/- 34 nM, n = 6, and 248 +/- 27 nM, n = 8, with dDAVP and AVP, respectively). Furthermore, in the same experiments V1 and V2 maximal effects were not additive ([Phe2,Orn8]VT = 154 +/- 21 nM, n = 6; dDAVP + [Phe2,Orn8]VT = 233 +/- 23 nM, n = 9). As AVP, dDAVP released intracellular calcium (delta[Ca2+]i in calcium-free medium = 182 +/- 24 nM, n = 8, vs. 182 +/- 14 nM, n = 6 with 10 nM dDAVP and AVP, respectively). Neither 8-(4-chlorophenyl-thio)-adenosine 3',5'-cyclic monophosphate nor forskolin modified [Ca2+]i. A cross-reaction of dDAVP with an oxytocin (OT) receptor can be excluded since 1) the specific OT agonist [Thr4,Gly7]OT (10 nM) increased only slightly [Ca2+]i (delta-[Ca2+]i = 20 +/- 5 nM, n = 11); 2) the dDAVP response was not altered by the specific OT antagonist [1-(beta-mercapto-beta,beta-cyclopentamethylene propionic acid),2-(O-methyl)tyrosine,4-threonine, 8-ornithine,9-tyrosylamide]vasotocin [d(CH2)5(1),O-Me-Tyr2,Thr4,Tyr-NH2(9)]OVT; 3) it was insensitive to V1 antagonists but was totally blocked by the V1/V2 antagonist [d(CH2)5(1),O-Et-Tyr2,Val4]AVP ([delta[Ca2+]i = 18 +/- 4 nM, n = 6). These results indicate that in IMCD AVP increases [Ca2+]i via both V1 and V2 receptors. [Ca2+]i variations due to V2 receptors involve a mechanism independent of adenylate cyclase and coupled to the same intracellular calcium pool as V1 and V2 receptors.

High Ca2+ inhibits AVP-dependent cAMP production in thick ascending limbs of Henle

1986 ◽  
Vol 250 (5) ◽  
pp. F770-F776 ◽  
Author(s):  
K. Takaichi ◽  
S. Uchida ◽  
K. Kurokawa
Keyword(s):  
Incubation Medium ◽  
Urine Concentration ◽  
Mouse Kidney ◽  
Ionophore A23187 ◽  
Channel Blockers ◽  
Camp Production ◽  
Outer Medulla ◽  
Catalytic Unit ◽  
Per Se ◽  
Collecting Tubules

To further gain insights into the mechanisms underlying impaired urine concentration in hypercalcemia, effects of increasing Ca2+ concentrations in the incubation medium on cAMP production in response to 10(-8) M arginine vasopression (AVP) were examined in thick ascending limbs of Henle (MTAL) and collecting tubules (MCT) dissected from outer medulla of mouse kidney. Increasing Ca2+ in the incubation medium from 1.0 mM to either 2.0 mM or 5.0 mM inhibited AVP-dependent cAMP production in MTAL but not in MCT. This inhibition of AVP-dependent cAMP production by 2.0 mM Ca2+ in MTAL was not reversed by verapamil or diltiazem. Also, Ca2+ ionophore A23187 did not inhibit AVP-dependent cAMP production in MTAL in the presence of 1.0 mM Ca2+. Increasing medium Ca2+ from 1.0 to 5.0 mM inhibited cAMP production in MTAL in response to both glucagon and forskolin by the magnitude comparable to that seen in response to AVP. These results show that high Ca2+ inhibits AVP-dependent cAMP production only in MTAL and not in MCT. In addition, the lack of effects of Ca2+ channel blockers and Ca2+ ionophore suggests that high ambient Ca2+ per se may inhibit AVP-dependent cAMP production in MTAL. The fact that high Ca2+ also suppressed cAMP production in response to glucagon or forskolin suggests that Ca2+ may inhibit AVP-dependent adenylate cyclase at postreceptor site(s), one of which is the catalytic unit of the enzyme.(ABSTRACT TRUNCATED AT 250 WORDS)

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