scholarly journals Disappearance of macrophage surface folds after antibody-dependent phagocytosis.

1981 ◽  
Vol 89 (2) ◽  
pp. 223-229 ◽  
Author(s):  
H R Petty ◽  
D G Hafeman ◽  
H M McConnell
Keyword(s):  
Electron Microscopy ◽  
Cell Surface ◽  
Guinea Pig ◽  
Surface Area ◽  
Surface Membrane ◽  
Peritoneal Macrophages ◽  
Injection Technique ◽  
Surface Areas ◽  
Transmission Electron ◽  
Uptake Data

We have employed the method of Burwen and Satir (J. Cell Biol., 1977, 74:690) to measure the disappearance of surface folds from resident guinea pig peritoneal macrophages after antibody-dependent phagocytosis. Unilamellar phospholipid vesicles containing dimyristoylphosphatidylcholine and 1 mol % dinitrophenyl-epsilon-aminocaproyl-phosphatidylethanolamine, a lipid that possesses a hapten headgroup, were prepared by an ether injection technique. These vesicles were taken up by macrophages in a time- and temperature-dependent fashion. Vesicles that contained ferritin trapped in the internal aqueous volume were identified within macrophages by transmission electron microscopy. Scanning electron microscopy has shown that macrophage surface folds decrease dramatically after phagocytosis. The surface fold length (micrometer) per unit smooth sphere surface area (micrometer2) decreases from 1.3 +/- 0.3 micrometer-1 to 0.53 +/- 0.25 micrometer-1 when cells are incubated in the presence of specific anti-DNP antibody and vesicles at 37 degrees C. No significant effect was observed in the presence of antibody only or vesicles only. Our studies shown that phagocytosis is associated with a loss of cell surface folds and a loss of cell surface area, which is consonant with current views of the endocytic process. On the basis of our uptake data, we estimate that approximately 400 micrometer2 of vesicle surface membrane is internalized. The guinea pig macrophage plasma membrane has a total area of approximately 400 micrometer2 in control studies, whereas the cells have roughly 300 micrometer2 after phagocytosis. These estimates of surface areas include membrane ruffles and changes directly related to changes in cell volume. We suggest that during antibody-dependent phagocytosis a membrane reservoir is made available to the cell surface.

Formation and processing of mesoporous barium titanate powders via the micelle template method

2006 ◽  
Vol 21 (4) ◽  
pp. 941-946
Author(s):  
Hong-Wen Wang ◽  
Chien-Hung Kuo ◽  
Tsai-Huei Liao ◽  
Ren-Jay Lin ◽  
Syh-Yuh Cheng
Keyword(s):  
Electron Microscopy ◽  
Barium Titanate ◽  
Surface Area ◽  
Self Assembly ◽  
Structural Characteristics ◽  
Mesoporous Structure ◽  
Surface Areas ◽  
Transmission Electron ◽  
Organic Surfactant ◽  
Titanium Tetra Isopropoxide

Mesoporous barium titanate powders having a 100- to 300-nm size were prepared by hydration and condensation of titanium tetra-isopropoxide and barium precursors in the presence of an organic surfactant, tetradecylamine, which was used as a self-assembly micelle. The processing and sintering of these mesoporous barium titanate powders has been investigated. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were used to identify the structural characteristics and morphologies of the powders. Mesoporous wormhole-like powders with surface areas around 53 ∼ 108 m2/g could be obtained after removing the micelle organics by calcination at 400 °C for 3 h. Powders derived using barium hydroxide were found to form a larger pore size and a higher surface area. The addition of acetic acid was also effective in increasing the surface area. A formation mechanism for the mesoporous structure is depicted. Heat treatment caused the mesoporous spheres to shrink, and 155- ∼ 330-nm grain sizes were readily obtained after pressureless sintering at 900 ∼ 1000 °C for 1 h in air.

Surface membrane regeneration in deciliated Tetrahymena

1983 ◽  
Vol 62 (1) ◽  
pp. 407-417
Author(s):  
N.E. Williams
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Membrane Proteins ◽  
Cell Surface ◽  
Surface Membrane ◽  
Membrane System ◽  
Ciliated Protozoa ◽  
Membrane Flow ◽  
Transmission Electron ◽  
Surface Marking

The induced synthesis of identified surface membrane proteins has been demonstrated in deciliated Tetrahymena. Cells in the process of regenerating cilia were also studied using transmission electron microscopy in order to obtain information on the deployment of new membrane at the cell surface. The results obtained suggest a pattern of membrane flow that includes the ‘pellicular alveoli’, a subsurface membrane system characteristically present in ciliated protozoa. The results of 125I surface-marking experiments were consistent with the notion that new membrane is added initially in non-ciliated regions, then subsequently flows laterally to cover regenerating cilia.

The Effect Of Storage On Platelet Morpholog

1981 ◽  
Author(s):  
A Sturk ◽  
L M Burt ◽  
T Hakvoort ◽  
J W ten cate ◽  
N Crawford
Keyword(s):  
Electron Microscopy ◽  
Membrane Structure ◽  
Room Temperature ◽  
Surface Membrane ◽  
Platelet Concentrates ◽  
Room Temperature Storage ◽  
Short Survival ◽  
Transmission Electron ◽  
Temperature Storage ◽  
Morphological Correlation

Platelet concentrates were stored for one, two or three days at 4°C (unagitated) or room temperature (unagitated and linearly agitated). The morphology of platelets in platelet concentrates, directly after twice washing at room temperature and after 60 min incubation of the washed platelets at 37°C was investigated by both scanning and transmission electron microscopy.Platelets in the freshly prepared concentrates are slightly activated, i.e. show some pseudopod formation. At 4°C platelets rapidly loose their discoid shape. After three days their surface membrane shows extensive folding, they are slightly vacuolated and have lost most of their granules. Incubation of these cold-stored platelets at 37°C does not induce reversal to the discoid shape.Room temperature storage results in reversal of the slight initial platelet activation. After three days unagitated platelets are slightly more vacuolated than platelets stored with agitation. Room temperature storage usually results in remarkably well preserved, discoid platelets. Occasionally however, agitated platelet concentrates contain a high proportion of odd shaped cells. As platelets stored at 4°C did not became discoid after incubation at 37°, the altered membrane structure could provide an explanation for their short survival upon transfusion. Our results also provide a morphological correlation with the slightly better recovery and survival of platelets stored agitated vs.- non-agitated platelets at room temperature.

Microstructure of LaB6-base thick film resistors

1992 ◽  
Vol 7 (8) ◽  
pp. 2225-2229 ◽  
Author(s):  
Z.G. Li ◽  
P.F. Carcia ◽  
P.C. Donohue
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Thick Film ◽  
Surface Area ◽  
Ion Milling ◽  
Cross Sectional ◽  
Electrically Conductive ◽  
Transmission Electron ◽  
High Temperature Processing ◽  
Thin Wedge

The microstructure of LaB6-base thick film resistors was investigated by cross-sectional transmission electron microscopy. The specimens were prepared by a technique that polished them to a thin wedge, thus avoiding ion-milling and permitting imaging over a distance of tens of microns. The resistor microstructure contained a finely divided electrically conductive phase of TaB2 and nonconducting crystals of CaTa4O11, formed during high temperature processing of glass and LaB6 ingredients of the thick film ink. Using higher surface area ingredients virtually suppressed the formation of CaTa4O11 crystals, and the microstructure became more uniform. Resistors made with higher surface area intermediates also had better voltage withstanding properties.

scholarly journals Impact of reaction vessel pressure on the synthesis of sliced activated carbon from date palm tree fronds

2015 ◽  
Vol 69 (5) ◽  
pp. 561-565 ◽  
Author(s):  
Muhammad Shoaib ◽  
Hassan Al-Swaidan
Keyword(s):  
Electron Microscopy ◽  
Flow Rate ◽  
Activated Carbons ◽  
Single Step ◽  
Reaction Vessel ◽  
Bet Surface Area ◽  
Palm Tree ◽  
Surface Areas ◽  
Transmission Electron ◽  
Co2 Flow

The effects of the reaction vessel pressure on the BET surface area, pore volume and pore size of the synthesis of sliced activated carbons (SAC) at 850?C starting from 0.10 to 0.40 bars were investigated. Other synthetic variables like dwell time, CO2 flow rate and heating ramp rate were kept constant during the whole study. Methodology involves a single step procedure using the mixture of gases (N2 and CO2). During activation flow rate of both gases are kept at 150 and 50ml/min respectively. The BET surface areas of the SAC prepared at 0.10, 0.15, 0.20, 0.25, 0.30, 0.35 and 0.40 bar after 30 minutes activation time are 666, 745, 895, 1094, 835, 658 and 625 m2/g, respectively. Scanning electron microscopy (SEM) for surface morphology, Energy dispersive spectroscopy (EDS), Transmission electron microscopy (TEM) for nano particle size were also carried out that also confirms the same trend.

Dipetalonema viteae: ultrastructural study on the in vitro interaction between rat macrophages and microfilariae in the presence of IgE antibody

Parasitology ◽  
1981 ◽  
Vol 82 (1) ◽  
pp. 55-62 ◽  
Author(s):  
M. A. Ouaissi ◽  
A. Haque ◽  
A. Capron
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ultrastructural Study ◽  
Peritoneal Macrophages ◽  
Immune Serum ◽  
Sequence Of Events ◽  
Transmission Electron ◽  
Dipetalonema Viteae ◽  
In Vitro Interaction

SUMMARYThe in vitro interaction between rat peritoneal macrophages and Dipetalonema viteae microfilariae in the presence of amicrofilaraemic rat immune serum was studied by transmission electron microscopy. The probable sequence of events leading to the killing of D. viteae microfilaria by macrophages is as follows. (a) Rat peritoneal macrophages in the presence of amicrofilaraemic rat immune serum adhere to the parasite surface, (b) the macrophages extend their pseudopodia around the parasite, (c) the ‘lysosome-like’ granules discharge their contents on to the parasite surface, (d) the lytic activity of these products begins at the parasite surface and (e) subsequent breaking of the microfilarial cuticle occurs, exposing the parasite intracellular material.

scholarly journals Catalytic Dehydrogenation of Methylcyclohexane by Pt Nanoparticles Supported on Nitrogen doped Carbon

2020 ◽  
Vol 194 ◽  
pp. 01030
Author(s):  
Jian Wang ◽  
Shiguang Fan ◽  
Xuan Xu ◽  
Huiru Yun ◽  
He Liu ◽  
...  
Keyword(s):  
Surface Area ◽  
Pt Nanoparticles ◽  
Catalytic Performance ◽  
Support Surface ◽  
Catalytic Dehydrogenation ◽  
Nitrogen Doped ◽  
Surface Areas ◽  
Transmission Electron ◽  
Methylcyclohexane Dehydrogenation ◽  
Nitrogen Doped Carbon

Pt nanoparticles supported on nitrogen doped carbon (Pt/CN) catalysts with different surface areas were obtained and characterized by transmission electron microscope （TEM） and brunner-emmet-teller （BET）. The characterized results showed that Pt nanoparticles dispersed uniformly on the support surface, and the surface area of the Pt/CN catalyst increased with the increase of annealing temperature. Subsequently, the catalytic performance of Pt/CN catalysts for methylcyclohexane dehydrogenation was studied. The activity of Pt/CN catalysts in methylcyclohexane dehydrogenation increased with the increase of the surface area, Pt/CN-1000 catalyst has the largest surface area and the highest catalytic activity, with the methylcyclohexane conversion of 99% and the TOF value of 424.78 h-1 at 180 ℃ for 150 minutes.

Nanostructured oxides for energy storage applications in batteries and supercapacitors

2009 ◽  
Vol 81 (8) ◽  
pp. 1489-1498 ◽  
Author(s):  
Amreesh Chandra ◽  
Alexander J. Roberts ◽  
Eric Lam How Yee ◽  
Robert C. T. Slade
Keyword(s):  
Electron Microscopy ◽  
Energy Storage ◽  
Specific Capacitance ◽  
Electrode Materials ◽  
Particle Morphology ◽  
Hydrothermal Route ◽  
Conductivity Enhancement ◽  
Surface Areas ◽  
Transmission Electron

Nanostructured materials are extensively investigated for application in energy storage and power generation devices. This paper deals with the synthesis and characterization of nanomaterials based on oxides of vanadium and with their application as electrode materials for energy storage systems viz. supercapacitors. These nano-oxides have been synthesized using a hydrothermal route in the presence of templates: 1-hexadecylamine, Tweens and Brij types. Using templates during synthesis enables tailoring of the particle morphology and physical characteristics of synthesized powders. Broad X-ray diffraction peaks show the formation of nanoparticles, confirmed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) investigations. SEM studies show that a large range of nanostructures such as needles, fibers, particles, etc. can be synthesized. These particles have varying surface areas and electrical conductivity. Enhancement of surface area as much as seven times relative to surface areas of starting parent materials has been observed. These properties make such materials ideal candidates for application as electrode materials in supercapacitors. Assembly and characterization of supercapacitors based on electrodes containing these active nano-oxides are discussed. Specific capacitance of >100 F g–1 has been observed. The specific capacitance decreases with cycling: causes of this phenomenon are presented.

scholarly journals The Transport System of Nacre Components through the Surface Membrane of Gastropods

2016 ◽  
Vol 672 ◽  
pp. 103-112 ◽  
Author(s):  
Elena Macías-Sánchez ◽  
Antonio G. Checa ◽  
Marc G. Willinger
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Calcium Carbonate ◽  
Lamellar Structure ◽  
Surface Membrane ◽  
Organic Matrix ◽  
X Ray ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Electron Energy Loss

The surface membrane is a lamellar structure exclusive of gastropods that is formed during the shell secretion. It protects the surface of the growing nacre and it is located between the mantle epithelium and the mineralization compartment. At the mantle side of the surface membrane numerous vesicles provide material, and at the nacre side, the interlamellar membranes detach from the whole structure. Components of nacre (glycoproteins, polysaccharides and calcium carbonate) cross the structure to reach the mineralization compartment, but the mechanism by which this occurs is still unknown. In this paper we have investigated the ultrastructure of the surface membrane and the associated vesicle layer by means of Transmission Electron Microscopy. Electron Energy Loss Spectroscopy and Energy-dispersive X-ray Spectroscopy were used for elemental analysis. The analyses revealed the concentration of calcium in the studied structures: vesicles, surface membrane, and interlamellar membranes. We discuss the possible linkage of calcium to the organic matrix.

Transmission electron microscopy (TEM) of equine conceptuses at 14 and 16 days of gestation

2010 ◽  
Vol 22 (2) ◽  
pp. 405 ◽  
Author(s):  
Ingrid Walter ◽  
Waltraud Tschulenk ◽  
Sven Budik ◽  
Christine Aurich
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Surface ◽  
Specific Cell ◽  
Fluid Uptake ◽  
Embryonic Disc ◽  
Transmission Electron ◽  
Cellular Junctions ◽  
Endodermal Cells ◽  
Specific Cell Surface

The present study gives a detailed ultrastructural description of equine conceptuses at Day 14 (n = 2) and Day 16 (n = 3) after ovulation. Whereas on Day 14 only primitive structures were seen, on Day 16 neurulation and formation of mesodermal somites had taken place. The ectoderm of the embryo itself and the surrounding trophoblast ectodermal cells were characterised by specific cell surface differentiations. At the embryonic ectodermal cell surface (14 and 16 days) remarkable protruded and fused cytoplasmic projections were seen, typically associated with macropinocytotic events involved in macromolecule and fluid uptake. This finding adds an important point to the expansion mode of the hypotone equine conceptus, which is characterised by ‘uphill’ fluid uptake. Numerous microvilli and coated endocytotic pits at the apical trophoblast membrane emphasised its absorptive character. Endodermal cells were arranged loosely with only apically located cellular junctions leaving large intercellular compartments. At the border of the embryonic disc apoptotic cells were regularly observed indicating high remodelling activities in this area. Conspicuous blister-like structures between ectoderm and mesoderm were seen in the trilaminar part of Day-14 and -16 conceptuses. These were strictly circumscribed despite not being sealed by cellular junctions between germinal layers. It is possible that these blisters are involved in embryo positioning; however, further studies are needed to verify this.

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