Scanning Electron Microscopic and Electrophoretic Observations on Barium Sulphate Used to Adsorb Clotting Factors

1975 ◽  
Vol 33 (02) ◽  
pp. 256-270
Author(s):  
R. M Howell ◽  
S. L. M Deacon

SummaryElectron microscopy and particle electrophoresis were found to be complementary techniques with which to complete the physical data from an earlier study on barium sulphates used to adsorb clotting factors from serum. The differences revealed by scanning electron microscopy (S. E. M.) in the physical shape of low and high density grades of barium sulphate particles appear to be of greater significance than charge as expressed by electrophoretic mobility, in determining whether or not precursor or preformed factor Xa is eluted.This conclusion was based on the finding that at pH values close to 7, where the adsorption from serum occurs, all samples with the exception of natural barytes were uncharged. However as the high-density, or soil-grade, was found by S. E. M. to consist of large solid crystals it was suggested that this shape might induce activation of factor X as a result of partial denaturation and consequent unfolding of the adsorbed protein. In contrast, uptake of protein into the centre of the porous aggregates revealed by S. E. M. pictures of low-density or X-ray grade barium sulphate may afford protection against denaturation and exposure of the enzyme site.The porous nature of particles of low-density barium sulphate compared with the solid crystalline forms of other grades accounts not only for its lower bulk density but also for its greater surface/gram ratio which is reflected by an ability to adsorb more protein from serum.Neither technique produced evidence from any of the samples to indicate the presence of stabilising agents sometimes used to coat particles in barium meals.

1976 ◽  
Vol 36 (01) ◽  
pp. 060-070
Author(s):  
S. L. M Deacon ◽  
R. M Howell

SummaryPhysical studies carried out on a range of protein and clotting factor adsorbents revealed marked morphological and charge differences. Their appearance in the scanning electron microscope could be used to classify the insoluble precipitates, calcium phosphate, barium sulphate and citrate, as either amorphorous or crystalline.Surface charge is difficult to define but the present studies on the sparingly-soluble salts, based on calcium and barium, have revealed that they can be subdivided on the basis of the presence or absence of a charge reversal point in the pH-mobility curve. The anion component appeared to determine this characteristic; it was noted that phosphate and citrate ions had a marked effect and gave a biased negative potential at all pH values. We concluded that where a divalent cation is cohabiting with a trivalent anion, the greater potential-determining ability of the latter will dominate the overall charge at the surface of a particle, even below pH7 and the absence of a positive potential gives a monophasic pH-mobility curve.Differences in both the physical appearance and electrophoretic mobility of the adsorbents studied reflect the wide variation in their chemical composition, especially among the various forms of calcium phosphate which, unlike barium sulphate, can include substituted ions such as hydroxyl, in their crystal lattice. The definition of these characteristics allows their behaviour towards clotting factors to be more easily predicted.


Author(s):  
Loren Anderson ◽  
Pat Pizzo ◽  
Glen Haydon

Transmission electron microscopy of replicas has long been used to study the fracture surfaces of components which fail in service. Recently, the scanning electron microscope (SEM) has gained popularity because it allows direct examination of the fracture surface. However, the somewhat lower resolution of the SEM coupled with a restriction on the sample size has served to limit the use of this instrument in investigating in-service failures. It is the intent of this paper to show that scanning electron microscopic examination of conventional negative replicas can be a convenient and reliable technique for determining mode of failure.


Author(s):  
Li Li-Sheng ◽  
L.F. Allard ◽  
W.C. Bigelow

The aromatic polyamides form a class of fibers having mechanical properties which are much better than those of aliphatic polyamides. Currently, the accepted morphology of these fibers as proposed by M.G. Dobb, et al. is a radial arrangement of pleated sheets, with the plane of the pleats parallel to the axis of the fiber. We have recently obtained evidence which supports a different morphology of this type of fiber, using ultramicrotomy and ion-thinning techniques to prepare specimens for transmission and scanning electron microscopy.


Author(s):  
Peter M. Andrews

Although there have been a number of recent scanning electron microscopic reports on the renal glomerulus, the advantages of scanning electron microscopy have not yet been applied to a systematic study of the uriniferous tubules. In the present investigation, scanning electron microscopy was used to study the ultrastructural morphology of the proximal, distal, thin loop, and collecting tubules. Material for observation was taken from rat kidneys which were fixed by vascular perfusion, sectioned by either cutting or fracturing technigues, and critically point dried.The brush border characterising proximal tubules is first detected on the luminal surface of Bowman's capsule adjacent to the urinary pole orifice. In this region one frequently finds irregular microvilli characterized by broad and flattened bases with occasional bulbous structures protruding from their surfaces.


2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Buzuayehu Abebe ◽  
Enyew Amare Zereffa ◽  
Aschalew Tadesse ◽  
H. C. Ananda Murthy

Abstract Metal oxide nanomaterials are one of the preferences as antibacterial active materials. Due to its distinctive electronic configuration and suitable properties, ZnO is one of the novel antibacterial active materials. Nowadays, researchers are making a serious effort to improve the antibacterial activities of ZnO by forming a composite with the same/different bandgap semiconductor materials and doping of ions. Applying capping agents such as polymers and plant extract that control the morphology and size of the nanomaterials and optimizing different conditions also enhance the antibacterial activity. Forming a nanocomposite and doping reduces the electron/hole recombination, increases the surface area to volume ratio, and also improves the stability towards dissolution and corrosion. The release of antimicrobial ions, electrostatic interaction, reactive oxygen species (ROS) generations are the crucial antibacterial activity mechanism. This review also presents a detailed discussion of the antibacterial activity improvement of ZnO by forming a composite, doping, and optimizing different conditions. The morphological analysis using scanning electron microscopy, field emission-scanning electron microscopy, field-emission transmission electron microscopy, fluorescence microscopy, and confocal microscopy can confirm the antibacterial activity and also supports for developing a satisfactory mechanism. Graphical abstract Graphical abstract showing the metal oxides antibacterial mechanism and the fluorescence and scanning electron microscopic images.


2017 ◽  
Vol 52 (18) ◽  
pp. 2431-2442 ◽  
Author(s):  
Harun Sepet ◽  
Necmettin Tarakcioglu ◽  
RDK Misra

The main purpose of this work is to study how the morphology of nanofillers and dispersion and distribution level of inorganic nanofiller influence the impact behavior and fracture probability of inorganic filler filled industrial high-density polyethylene nanocomposites. For this study, nanoclay and nano-CaCO3 fillers–high-density polyethylene mixings (0, 1, 3, 5 wt.% high-density polyethylene) was prepared by melt-mixing method using a compounder system. The impact behavior was examined by charpy impact test, scanning electron microscopy, and probability theory and statistics. The level of the dispersion was characterized with scanning electron microscopy energy dispersive X-ray spectroscopy analysis. The results showed rather good dispersion of both of inorganic nanofiller, with a mixture of exfoliated and confined morphology. The results indicated that the impact strength of the industrial nanocomposite decreased with the increase of inorganic particulate content. The impact reliability of the industrial nanocomposites depends on the type of nanofillers and their dispersion and distribution in the matrix.


2021 ◽  
Vol 9 (10) ◽  
pp. 1386-1393
Author(s):  
Jayshree Sandesh Thaware ◽  

Pollen is appropriately referred by some as Golden dust extremely valuable on account of their tremendous applications in science, industries and public health. No other plant part even though extremely tiny in size is packed with so much information and power. Similar to other plant parts, pollen characters are so varied that the classification system of plants can be built up entirely on the basis of pollen morphology.Palynology is the distinct branch of biology that deals with the dispersed microscopic tiny living and fossil entities including pollen grains, spores, algal and fungal fragments and others. An important aspect of Palynology is the Pollen morphology. The importance of Palynology in taxonomic and phylogenetic consideration of plants is well known. The changes occurring through hybridization and years of cultivation are reflected in pollen morphology. The scope and interest in the study of pollen morphology have widened with the advent of Scanning Electron Microscopy (SEM) and with regards to unipalynous taxa particularly the understanding of finer morphology is of fundamental importance. SEM gives a correct understanding of exine surface as the electron photographs of the surface replica of the exine provides the exact picture of the ornamentation pattern. The variation in the pollen morphological characters helps in the classification of plant taxa and their assessment of their phylogenetic relationship. In the present investigation, the pollen morphological studies were carried out of some ethnomedicinal plants like Catharanthus roseus, Allamanda cathartica, Datura metel, Brassica juncea, Raphanus sativus and Cleome viscosa pollen grains by Scanning electron microscopy. All that they possess anticancer characteristics in common.


1982 ◽  
Vol 28 (10) ◽  
pp. 1119-1126 ◽  
Author(s):  
M. Bastide ◽  
S. Jouvert ◽  
J.-M. Bastide

The early events in the interaction of two polyene (amphotericin B and nystatin) and five imidazole (clotrimazole, ketoconazole, miconazole, isoconazole, and econazole) antimycotics used at fungicidal concentrations with the surface of Candida albicans were studied by scanning electron microscopic examination of treated intact young yeast cells, treated spheroplasts, and spheroplasts liberated from treated young yeast cells. In all cases, treatment lasted 2 h. The polyenes passed through the yeast cell wall and interacted with the cytoplasmic membrane causing the spheroplasts to lose their characteristic spheric form and to liberate their contents. Clotrimazole caused the formation of numerous circular openings in the cytoplasmic membrane, but only when the agent was used to treat spheroplasts directly. Ketoconazole, miconazole, isoconazole, and econazole interacted with the cell wall causing formation of convolutions and wrinkles. The three imidazole derivatives that are structurally closely related, miconazole, isoconazole, and econazole, inhibited the enzyme-catalyzed release of spheroplasts from young yeast cells.


1980 ◽  
Vol 30 (2) ◽  
pp. 588-600
Author(s):  
S C Holt ◽  
A C Tanner ◽  
S S Socransky

Selected human oral and nonoral strains of the genera Actinobacillus and Haemophilus were examined by transmission and scanning electron microscopy. The strains examined were morphologically identical to recognized Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, and Haemophilus paraphrophilus. By transmission electron microscopy, the cells were typically gram negative in morphology, with several strains possessing some extracellular ruthenium red-staining polymeric material. Numerous vesicular structures, morphologically identical to lipopolysaccharide vesicles, were seen to originate from and be continuous with the surface of the outer membrane. Large numbers of these vesicles were also found in the external environment. Scanning electron microscopic observations revealed that both actinobacilli and haemophili possessed surface projections and an amorphous surface material which connected and covered adjacent cells.


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