The contribution of osmium tetroxide to the image quality and detectability of elements in cells studies by electron spectroscopic imaging

1990 ◽  
Vol 48 (3) ◽  
pp. 778-779
Author(s):  
Rebecca C. Stearns ◽  
Cindy L. Hastings ◽  
Marshall Katler ◽  
John J. Godleski
Keyword(s):  
Heavy Metals ◽  
Electron Microscope ◽  
Osmium Tetroxide ◽  
Spectroscopic Imaging ◽  
Electron Spectroscopic Imaging ◽  
Soluble Ions ◽  
The Times ◽  
Fe Ions

Osmium tetroxide has been recognized as an excellent fixative which also contributes to the quality of TEM micrographs (1). In the preparation of biological materials for electron spectroscopic imaging (ESI) of 30 run sections with the Zeiss CEM902 electron microscope, OsO4 is usually used in fixation, but poststaining with heavy metals is not needed. However, the extent of the contribution of OsO4, to the images obtained had not been defined clearly, nor was it clear the extent to which the presence of OsO, might obscure detection of elements by ESI or EELS. To establish optimal liquid fixation for the preservation of soluble ions we monitored the loss of Fe ions during preparation. To determine the role of Os4O, in ESI imaging, hamster alveolar macrophages (AMS) were incubated with 0.ImM FeCLo for 15 minutes, then fixed with 2.5% glutaraldehyde in 0.IM K phosphate buffer in 0.01% CaCLo, then grouped into 6 samples varying the times and percentages of OsO, . One sample was not exposed to any OsO4.

The Current Situation in Chemical Stabilization of Biological Materials

1972 ◽  
Vol 30 ◽  
pp. 132-133
Author(s):  
John H. Luft
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Osmium Tetroxide ◽  
Molecular Level ◽  
Cross Linking ◽  
Chemical Stabilization ◽  
Specimen Preparation ◽  
Sufficient Condition ◽  
Radio Telescopes

With information processing devices such as radio telescopes, microscopes or hi-fi systems, the quality of the output often is limited by distortion or noise introduced at the input stage of the device. This analogy can be extended usefully to specimen preparation for the electron microscope; fixation, which initiates the processing sequence, is the single most important step and, unfortunately, is the least well understood. Although there is an abundance of fixation mixtures recommended in the light microscopy literature, osmium tetroxide and glutaraldehyde are favored for electron microscopy. These fixatives react vigorously with proteins at the molecular level. There is clear evidence for the cross-linking of proteins both by osmium tetroxide and glutaraldehyde and cross-linking may be a necessary if not sufficient condition to define fixatives as a class.

Variations in Mineral/heavy metals profiling and preventive role of trichomes in Peach Fruits treated with CaC2

2020 ◽  
Vol 23 ◽  
Author(s):  
Muhammad Irfan ◽  
Safdar Abbas ◽  
Beenish Jehan Azhar ◽  
Shakeel Ahmad ◽  
Hafsa Muhammad ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Nutritional Value ◽  
Fine Powder ◽  
Calcium Carbide ◽  
Control Group ◽  
Tandem Accelerator ◽  
Health Promoting ◽  
Elemental Profiling

Background: Phytonutrients in peach fruits have health promoting antioxidants against various chronic diseases. However, there is no extensive data to show the nutritional values of Local peach cultivars after post-harvest treatments. Objective: Mainly this study was objective to determine the effect of calcium carbide on nutritional value and quality of fruits of Pakistani peach cultivars. Methods: The peach fruits were collected from three different peach orchids of KPK and the fruits were divided into 4 groups while 5th group was collected from local fruit shop. Each experimental group was treated with different concentration of calcium carbide whereas control group was not treated. The peel and pulp samples were oven dried and ground to fine powder separately. The elemental compositions were determined using Particle Induced X-ray emission and Pelletron Tandem Accelerator. Result: Sixteen elements were identified in peach fruits and the elements were Al, P, S, Cl, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, and Se. In peel, concentration of some elements increased or decreased after treatment with CaC2 while in pulp the conc. of nearly all detected elements was increased in treated samples. We found significantly high amount of heavy metals traces including As, Se, Co, Si, and P in peach fruits treated with CaC2. Interestingly, the presence of trichomes in peach skin prevents the transfer of these heavy metals deep into the pulp which was also verified by the elemental profiling of nectarines. Conclusion: Conclusively, the artificial ripening with CaC2 changed the nutritional value of peach fruits that has higher health risks if consume with the peel. According to our best knowledge, this is the first report that highlights the effects of CaC2 which deteriorate the nutritional value of peach fruits in Pakistan.

scholarly journals Role of green spaces for migration and setting of heavy metals (as illustrated by Holosiivskyi National Nature Park, Kyiv)

2021 ◽  
pp. 97-105
Author(s):  
T. S. Tesolkina ◽  
D. V. Lukashov
Keyword(s):  
Heavy Metals ◽  
Forest Litter ◽  
Green Spaces ◽  
Winter Period ◽  
Soil System ◽  
Atmospheric Air ◽  
Leading Role ◽  
Nature Park

Air pollution by heavy metals in the urbanized surroundings presents a serious threat to human health and the environment. Road dust is distinguished as a high-level pollutant and characterized by a significant content of heavy metals. Green spaces play a leading role when it comes to improving the quality of atmospheric air in megalopolises. They trap pollutants. Most of them settle on the surfaces of plant leaves, but some can be also absorbed through the stomata. As a result of these processes, pollutants, along with fallen leaves, can later migrate to other components of the ecosystem. An important component of this system is forest litter that plays a kind of trigger role by regulating the directions of substance flows in the “leaves-litter-soil” system, keeping chemical elements from leaching out and evenly distributing their inflows. Thus, forest litter functions as a sort of biogeochemical barrier and plays a leading role in the ability of ecosystems to self-regulate. Thus, the purpose of this work was to assess the role of green spaces in improving the quality of atmospheric air in the urban surroundings and to conduct a preliminary assessment of the features of the processes of heavy metals transformation within the forest litter. The model site of research is located within the territory of Holosiivskyi forest, a part of the Holosiivskyi National Nature Park (Kyiv). The content of heavy metals in the forest litter was determined using the methods of atomic absorption spectrophotometry. The results of the study of Cu, Ni, Pb, Cd, Cr and Zn content annual dynamics within the forest litter of the hornbeam forest of the Holosiivskyi National Nature Park show that the maximum concentrations are typical for the summer period, when the litter reserves sharply decrease, and the minimum ones – for the autumn-winter period during their accumulation. Comparison of the distribution of heavy metals content within the leaf and fermented layers showed that, under the conditions of the model area, Zn, Cu, and Ni are predominantly accumulated right in the leaf layer of the forest litter. Moreover, it was revealed that the processes of leaf litter mineralization lead to migration of Cu, Ni, Pb, Cd and Cr, and setting of Zn.

Resolution and contrast enhancement on biological specimens by means of electron spectroscopic imaging (ESI)

1986 ◽  
Vol 44 ◽  
pp. 68-69
Author(s):  
U. B. Hezel ◽  
R. Bauer ◽  
E. Zellmann ◽  
W. I. Miller
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Electron Beam ◽  
Contrast Enhancement ◽  
Electron Scattering ◽  
Biological Material ◽  
Spectroscopic Imaging ◽  
Chromatic Aberration ◽  
Electron Spectroscopic Imaging ◽  
Chromatic Aberrations

The main elemental constituents of biological material - C,H,N,O - are the same elements found in typical embedding materials. Because of this the contrast of unstained biological material is very poor. Additionally, electron scattering by low Z atoms is mainly inelastic resulting in unsharp images from the concomitant chromatic aberration.These effects have been delt with by employing stains of such heavy metals as Os, U, or Pb. These stains are for the most part located at the biological structures themselves and primarily scatter the electron beam elastically. Thus with ultra-thin (<80nm) heavy metal stained sections of biological material the contrast in the CTEM is very good and chromatic aberrations are negligable.

scholarly journals Peran Teknologi Pendidikan dalam Meningkatkan Kualitas Pendidikan di Era Disrupsi

2021 ◽  
Vol 3 (01) ◽  
pp. 104-112
Author(s):  
Unik Hanifah Salsabila ◽  
Munaya Ulil Ilmi ◽  
Siti Aisyah ◽  
Nurfadila Nurfadila ◽  
Rio Saputra
Keyword(s):  
Educational Technology ◽  
Progressive Era ◽  
Media Coverage ◽  
Learning Problems ◽  
Educational Goals ◽  
Library Research ◽  
The World ◽  
The Times

Along with the times, technology in its development certainly brings changes to life, especially in the world of education which will also continue to experience development. This article aims to determine the role of educational technology in improving the quality of education in this progressive era. So it is hoped that educational technologists will no longer feel doubtful and interested in adapting and being able to take advantage of technology with all its benefits in educational life. In writing this article we use a literature review method (library research), where researchers collect materials related to research from books, journals, scientific articles, literature and mass media coverage by describing and describing the data. Based on the discussion, it can be concluded that educational technology was created to solve learning problems by facilitating and providing alternatives and new innovations in the world of education. That way educational technology can make it easier to achieve educational goals.

scholarly journals Simulation centre as a strategic instrument of medical education quality improvement

2019 ◽  
Vol 2019 (2 (127)) ◽  
pp. 76-79
Author(s):  
Khachatryan Robert ◽  
Ashot Avagimyan
Keyword(s):  
Medical Education ◽  
New Technologies ◽  
Educational Institution ◽  
The Times ◽  
The One ◽  
Simulation Centre ◽  
Medical University

In the 21st century, medicine alongside with medical education, is a dynamically developing industry, and is experiencing a real renaissance of its development. New technologies are gradually replacing the old methods, which undoubtedly increases the quality of provided services, reducing the probability of medical errors, and favourably affects the mortality rate (for example, echocardiography, both transthoracic and intra-oesophageal, has replaced percussion and heart palpation). However, relatively old methods, for example, such as auscultation of the heart, still do not lose their significance or effectiveness, in particular, it is worth noting the high information content of this instrumental examination when dealing with valvular pathologies of the heart (for example, critical aortic stenosis). It is known that any educational institution, in particular, a medical one, must keep abreast of the times and correspond to modern needs. The management of medical universities, making long-term strategies for their development, in order to increase competitiveness, both their own and the one of their students, should maximally provide their clinics with the latest equipment, which will undoubtedly allow preserving its niche, perhaps at the regional or world level. For example, the Yerevan State Medical University named after Mkhitar Heratsi is of inter-regional importance, being the leading medical educational institution among the countries of the Caucasus and the Anterior Asia. In the process of introducing new technologies among students of medical universities, a competence-based approach is the opening of highly equipped imulation centres, where the future doctor and/or a certain doctor will be given a unique in the medical world chance, a chance for error, since it is well-known that a doctor’s mistake can cost life of the whole people. This article is devoted to the pivotal role of the simulation centre within the modern educational system of medical universities as well as the strategy for its construction. Keywords: medical education, doctor, simulation centre.

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