Solvent-assisted osmium staining of butyl acrylate and ethylene-propylene-diene in a styrene acrylonitrile matrix

In order to optimize the toughening effect of elastomers in engineering polymers, it is necessary to characterize the size, morphology and dispersion of the specific elastomer within the polymer matrix. For unsaturated elastomers such as butadiene or isoprene, staining with osmium tetroxide is a well established procedure. The residual carbon-carbon double bond in these materials is the reactive site and forms a 1,2-dilato complex with the OsO4. Incorporation of osmium tetroxide into the elastomer not only produces sufficient contrast for TEM, but also crosslinks the elastomer sufficiently so that ultramicrotomy can be accomplished at room temperature with minimal distortion.Blends containing saturated elastomers such as butyl acrylate (BA) and ethylene propylene diene monomer (EPDM) cannot be stained directly with OsO4 because effective reaction sites such as C=C or -NH2 are not available in sufficient number. If additional reaction sites can be introduced selectively into the elastomer by a chemical reaction or the absorption of a solvent, a modified, two-step osmium staining procedure is possible.

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Immunogold localization of HMB-45 antigen in pulmonary lymphangiomyomatosis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100141366 ◽

1995 ◽

Vol 53 ◽

pp. 998-999

Author(s):

J.M. Minda ◽

E. Dessy ◽

G. G. Pietra

Keyword(s):

Smooth Muscle ◽

Smooth Muscle Cells ◽

Room Temperature ◽

Osmium Tetroxide ◽

Muscle Cells ◽

Ultrastructural Localization ◽

Reproductive Age ◽

Thin Sections ◽

Smooth Muscle Proliferation ◽

Hmb 45

Pulmonary lymphangiomyomatosis (PLAM) is a rare disease occurring exclusively in women of reproductive age. It involves the lungs, lymph nodes and lymphatic ducts. In the lungs, it is characterized by the proliferation of smooth muscle cells around lymphatics in the bronchovascular bundles, lobular septa and pleura The nature of smooth muscle proliferation in PLAM is still unclear. Recently, reactivity of the smooth muscle cells for HMB-45, a melanoma-related antigen has been reported by immunohistochemistry. The purpose of this study was the ultrastructural localization of HMB-45 immunoreactivity in these cells using gold-labeled antibodies.Lung tissue from three cases of PLAM, referred to our Institution for lung transplantation, was embedded in either Poly/Bed 812 post-fixed in 1% osmium tetroxide, or in LR White, without osmication. For the immunogold technique, thin sections were placed on Nickel grids and incubated with affinity purified, monoclonal anti-melanoma antibody HMB-45 (1:1) (Enzo Diag. Co) overnight at 4°C. After extensive washing with PBS, grids were treated with Goat-anti-mouse-IgG-Gold (5nm) (1:10) (Amersham Life Sci) for 1 hour, at room temperature.

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Opening images of synaptic vesicles and calcium localization by means of microwave fixation method

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100134508 ◽

1990 ◽

Vol 48 (2) ◽

pp. 182-183

Author(s):

Vinci Mizuhira ◽

Hiroshi Hasegawa

Keyword(s):

Synaptic Vesicles ◽

Room Temperature ◽

Osmium Tetroxide ◽

Sampling Procedure ◽

Fixation Method ◽

Potassium Oxalate ◽

X Ray ◽

Cacodylate Buffer ◽

Ultrathin Sections ◽

Microwave Fixation

Microwave irradiation (MWI) was applied to 0.3 to 1 cm3 blocks of rat central nervous system at 2.45 GHz/500W for about 20 sec in a fixative, at room temperature. Fixative composed of 2% paraformaldehyde, 0.5% glutaraldehyde in 0.1 M cacodylate buffer at pH 7.4, also contained 2 mM of CaCl2 , 1 mM of MgCl2, and 0.1% of tannic acid for conventional observation; and fuether 30-90 mM of potassium oxalate containing fixative was applied for the detection of calcium ion localization in cells. Tissue blocks were left in the same fixative for 30 to 180 min after MWI at room temperature, then proceeded to the sampling procedure, after postfixed with osmium tetroxide, embedded in Epon. Ultrathin sections were double stained with an useal manner. Oxalate treated sections were devided in two, stained and unstained one. The later oxalate treated unstained sections were analyzed with electron probe X-ray microanalyzer, the EDAX-PU-9800, at 40 KV accelerating voltage for 100 to 200 sec with point or selected area analyzing methods.

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Observations of thick and thin sections in a field-emission SEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100172826 ◽

1994 ◽

Vol 52 ◽

pp. 1018-1019

Author(s):

W. P. Wergin ◽

S. Roy ◽

E. F. Erbe ◽

C. A. Murphy ◽

C. D. Pooley

Keyword(s):

Electron Microscope ◽

Field Emission ◽

Room Temperature ◽

Osmium Tetroxide ◽

Uranyl Acetate ◽

Chemical Fixation ◽

Thin Sections ◽

Transmission Electron ◽

Conventional Transmission Electron Microscope ◽

Scanning Electron

Larvae of the nematode, Steinernema carpocapsae Weiser strain All, were cryofixed and freezesubstituted for 3 days in acetone containing 2% osmium tetroxide according to established procedures. Following chemical fixation, the nematodes were brought to room temperature, embedded in Spurr's medium and sectioned for observation with a Hitachi S-4100 field emission scanning electron microscope that was equipped with an Oxford CT 1500 Cryotrans System. Thin sections, about 80 nm thick, similar to those generally used in conventional transmission electron microscope (TEM) studies were mounted on copper grids and stained with uranyl acetate for 30 min and lead citrate for 5 min. Sections about 2 μm thick were also mounted and stained in a similar fashion. The grids were mounted on an Oxford grid holder, inserted into the microscope and onto a cryostage that was operated at ambient temperature. Thick and thin sections of the larvae were evaluated and photographed in the SEM at different accelerating voltages. Figs. 4 and 5 have undergone contrast conversion so that the images would resemble transmitted electron micrographs obtained with a TEM.

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Effects of Mg2+ on Chromatic Structure in Isolated Chicken Liver Nuclei

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100158194 ◽

1990 ◽

Vol 48 (3) ◽

pp. 130-131

Author(s):

Soichiro Arai ◽

Yuh H. Nakanishi

Keyword(s):

Chromatin Structure ◽

Room Temperature ◽

Osmium Tetroxide ◽

Divalent Cations ◽

Chromatin Condensation ◽

Chicken Liver ◽

Electron Microscopic ◽

Razor Blade ◽

Microscopic Studies ◽

Liver Nuclei

Although many electron microscopic studies on extracted chromatin have provided considerable information on chromatin condensation induced by divalent cations, there is only a little literature available on the effects of divalent cations on chromatin structure in intact nuclei. In the present study, the effects of Mg2+ on chromatin structure in isolated chicken liver nuclei were examined over a wide concentration range of Mg2+ by scanning electron microscopy.Nuclei were prepared from chicken liver by the method of Chauveau et al. with some modifications. The nuclei were suspended in 25 mM triethanolamine chloride buffer (pH7.4) with 1 mM EDTA or in the buffer with concentrations of MgCl2 varying from 1 to 50 mM. After incubation for 1 min at 0°C, glutaraldehyde was added to 1.8% and the nuclei were fixed for 1 h at 4°C. The fixed nuclei were mixed with 15% gelatin solution warmed at about 40°C, and kept at room temperature until the mixture set. The gelatin containing the nuclei was fixed with 2% glutaraldehyde for 2-4 h, and cut into small blocks. The gelatin blocks were conductive-stained with 2% tannic acid and 2% osmium tetroxide, dehydrated in a graded series of ethanol, and freeze-cracked with a razor blade in liquid nitrogen.

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The effect of polyhedral oligomeric silsesquioxanes (POSSs) incorporation in ethylene-propylene-diene-terpolymer (EPDM): a thermal study

Journal of Thermal Analysis and Calorimetry ◽

10.1007/s10973-021-10994-x ◽

2021 ◽

Author(s):

Ignazio Blanco ◽

Traian Zaharescu

Keyword(s):

Room Temperature ◽

Thermal Characterization ◽

Polyhedral Oligomeric Silsesquioxanes ◽

Dsc Analysis ◽

Γ Irradiation ◽

Scanning Calorimetry ◽

Ethylene Propylene ◽

Oligomeric Silsesquioxane ◽

Ethylene Propylene Diene Terpolymer ◽

Dynamic Heating

AbstractA series of ethylene-propylene-diene-terpolymer (EPDM)/polyhedral oligomeric silsesquioxane (POSS) composites at different percentage of POSS were prepared and subjected to γ-irradiation. Both irradiated and non-irradiated EPDM and composites were investigated by the means of thermal analysis to verify if the presence of POSS molecules is able to reduce the oxidation level of free radicals generated during the degradation and to evaluate the effects of the irradiation. EPDM composites at 1, 3 and 5 mass% of POSS were thus degraded in a thermogravimetric (TG) balance in dynamic heating conditions (25–700 °C), in both inert and oxidative atmosphere by flowing nitrogen and air respectively. Thermal characterization was then completed by carrying out Differential Scanning Calorimetry (DSC) analysis from sub-ambient to better highlight the melting of the polymer and polymer composites occurring just above the room temperature. FTIR spectroscopy was also performed for the prepared samples to check the presence of the molecular filler in the composites and for the TG’s residue at 700 °C, in order to evaluate its nature. DSC and TGA parameters were detected and discussed to have information about the effect of the degradation’s environment, the effect of irradiation on polymer stabilization and the effect of POSS content in the polymer matrix.

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Dynamic Testing of Automotive Rubber Parts by the Resonant Beam Tester. Effect of Polymer, Deflection, Age, and Temperature on Dynamic Rate

Rubber Chemistry and Technology ◽

10.5254/1.3540384 ◽

1964 ◽

Vol 37 (4) ◽

pp. 866-877 ◽

Cited By ~ 2

Author(s):

M. Lowman ◽

H. E. Keller

Keyword(s):

Natural Rubber ◽

Room Temperature ◽

Dynamic Testing ◽

Effect Of Temperature ◽

Ethylene Propylene ◽

Rate Decrease ◽

Resonant Beam

Abstract When the recipe is basically the same, different polymers differ in dynamic rate and damping. Ethylene—propylene terpolymer, SBR, neoprene, and butyl gave higher dynamic rate and higher damping than natural rubber, polyisoprene, and the blend of polyisoprene and cis 1,4-polybutadiene. The lowest dynamic rate and lowest damping is obtained with polyisoprene. At room temperature, polymers having the highest damping also have the largest ratio of dynamic to static rate. One cannot predict the effect of temperature on dynamic rate by measuring static rate at these temperatures. Increase in temperature lowers dynamic rate, decrease in temperature increases it. This effect was least with a blend of polyisoprene and cis 1,4-polybutadiene, closely followed by polyisoprene, and natural rubber. The largest change was with butyl. Dynamic rate increases with time after cure. After 26 hr, dynamic rate is a function of the logarithm of time. This effect is least with polyisoprene. Natural rubber, SBR, EPT, neoprene and a blend of polyisoprene with cis 1,4-polybutadiene all follow Equation (1). Butyl has, by far, the greatest change in dynamic rate with time. Reducing the deflection from 0.012 in. to 0.004 in. linearly increased the dynamic rate. Times of vibration between 2 minutes and 60 minutes at room temperature had no effect on dynamic rate.

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Hydroformylation of unsaturated esters and 2,3-dihydrofuran under solventless conditions at room temperature catalysed by rhodium N-pyrrolyl phosphine catalysts

New Journal of Chemistry ◽

10.1039/c9nj04438h ◽

2019 ◽

Vol 43 (43) ◽

pp. 16990-16999 ◽

Cited By ~ 3

Author(s):

W. Alsalahi ◽

A. M. Trzeciak

Keyword(s):

Vinyl Acetate ◽

Methyl Acrylate ◽

Butyl Acrylate ◽

Room Temperature ◽

Allyl Acetate ◽

Unsaturated Esters

Complexes of the type HRh(CO)L3 (where L is an N-pyrrolyl phosphine, e.g. P(NC4H4)3, Ph(NC4H4)2, or PPh2(NC4H4)) were applied in the hydroformylation of less reactive unsaturated substrates (allyl acetate, butyl acrylate, methyl acrylate, 2,3-dihydrofuran, vinyl acetate).

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