scholarly journals PHYSICAL STUDIES OF PHOSPHOLIPIDS

1966 ◽  
Vol 30 (1) ◽  
pp. 1-11 ◽  
Author(s):  
D. Chapman ◽  
D. J. Fluck
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Transition Temperature ◽  
Light Microscopy ◽  
Osmium Tetroxide ◽  
Negative Staining ◽  
Hydrocarbon Chains ◽  
Myelin Figures

On heating pure, fully saturated 2,3-diacyl-DL-phosphatidyl-ethanolamines and 2,3-diacylphosphatidyl-cholines (lecithins) in water to the transition temperature at which large endothermic heat changes occur, they are observed, by light microscopy, to form myelin figures. This result is discussed in terms of the large difference in the transition temperature for "melting" of the hydrocarbon chains of unsaturated and saturated phospholipids and is illustrated by means of differential thermal analysis (D.T.A.) curves. These structures have been examined by electron microscopy after negative staining and after reaction with osmium tetroxide. Typical phospholipid lamella structures are seen in the phosphatidylcholines after negative staining, and in the phosphatidyl-ethanolamines after both negative staining and osmium fixation. The distances across these lamellae have been measured. Some preliminary investigations of the nature of the osmium tetroxide reaction with the phosphatidyl-ethanolamines have been made.

PENINGKATAN LAJU DISOLUSI ACYCLOVIR DENGAN METODE SISTEM DISPERSI PADAT MENGGUNAKAN POLOXAMER 188

2016 ◽  
Vol 5 (1) ◽  
pp. 6
Author(s):  
Budi Setiawan ◽  
Erizal Zaini ◽  
Salman Umar
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Differential Thermal Analysis ◽  
Fourier Transform Infrared ◽  
X Ray Diffraction ◽  
Poloxamer 188 ◽  
X Ray ◽  
Scanning Electron

Sebuah penelitian tentang sistem dispersi padat dari asiklovir dengan poloxamer 188 telah dilakukan formulasi dengan pencampuran secara fisika dengan rasio 1 : 1, 1 : 3, 1 : 5 dan dispersi padat 1 : 1, 1 : 3, 1 : 5 dan penggilingan 1:1 sebagai pembanding. Dispersi padat dibuat menggunakan metode pencairan (fusi), yang digabung dengan poloxamer 188 pada hotplate kemudian asiklovir dimasukkan ke dalam hasil poloxamer 188 lalu di kocok hingga membentuk masa homogen. Semua formula yang terbentuk termasuk asiklovir poloxamer 188 murni dianalisis karakterisasinya dengan Differential Thermal Analysis (DTA), X-ray Diffraction, Scanning Electron Microscopy (SEM), dan Fourier Transform Infrared (FTIR), kemudian pengambilan dilakukan  (penentuan kadar) mengunakan spektrofotometer UV pada panjang gelombang 257,08 nm dan uji laju disolusi dengan aquadest bebas CO2 menggunakan metode dayung. Hasil pengambilan  (penentuan kadar) menunjukkan bahwa semua formula memenuhi persyaratan farmakope Amerika edisi 30 dan farmakope Indonesia edisi 4 yaitu 95-110%. Sedangkan hasil uji laju disolusi untuk campuran fisik 1: 1, dan dispersi padat 1: 1, dan penggilingan 1: 1 menunjukkan peningkatan yang nyata dibandingkan asiklovir murni. Hal ini juga dapat dilihat dari hasil perhitungan statistik  menggunakan analisis varian satu arah  SPSS 17.

scholarly journals Influence of the Al content on the phase transformations in Cu-Al-Ag alloys

2003 ◽  
Vol 28 (1) ◽  
pp. 33-38 ◽  
Author(s):  
A. T. Adorno ◽  
A. V. Benedetti ◽  
R. A. G. da Silva ◽  
M. Blanco
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Transition Temperature ◽  
Phase Transformations ◽  
Decomposition Reaction ◽  
Phase Decomposition ◽  
Stability Range ◽  
X Ray ◽  
Al Content ◽  
The Stability

The influence of the Al content on the phase transformations in Cu-Al-Ag alloys was studied by classical differential thermal analysis (DTA), optical microscopy (OM) and X-ray diffractometry (XRD). The results indicated that the increase in the Al content and the presence of Ag decrease the rate of the <FONT FACE=Symbol>b</font>1 phase decomposition reaction and contribute for the raise of this transition temperature, thus decreasing the stability range of the perlitic phase resulted from the b1 decomposition reaction.

scholarly journals Ultrastructure of the Developing Aleurone Cells of Wheat Grain

1963 ◽  
Vol 16 (4) ◽  
pp. 768 ◽  
Author(s):  
MS Buttrose
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Cell Walls ◽  
Osmium Tetroxide ◽  
Aleurone Layer ◽  
Wheat Grain ◽  
Aleurone Cells ◽  
Wheat Kernel ◽  
Large Numbers ◽  
Inner Surface

The developing aleurone layer cells of the wheat kernel have been investigated by electron microscopy and the results compared with those of light microscopy. Two weeks after flowering vacuoles appear in the cells and deposits accumulate in these until maturity when the cells are filled 'with the resulting "vacuolar units" 2-3p. in diameter, corresponding to the aleurone grains of light microscopy. The wheat aleurone grain consists of a bounding membrane (of vacuole origin) enclosing a matrix in which are embedded spherical deposits. Some of these deposits are translucent and others opaque to electrons after potassium permanganate and osmium tetroxide fixation. At all stages examined the cytoplasm of aleurone cells contained large numbers of small unidentified bodies with irregular outline and dense contents. At first they are dispersed, but towards maturity are organized as a monolayer over the surface of each aleurone grain and the inner surface of the cell walls. The apparent specificity of these structures to aleurone cells is discussed in relation to future chemical and physiological studies of the tissue.

Transmission Electron Microscopy of Lipid Vesicles for Drug Delivery: Comparison between Positive and Negative Staining

2010 ◽  
Vol 16 (4) ◽  
pp. 456-461 ◽  
Author(s):  
Valentina Bello ◽  
Giovanni Mattei ◽  
Paolo Mazzoldi ◽  
Nicoletta Vivenza ◽  
Paolo Gasco ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Drug Delivery ◽  
Transmission Electron Microscopy ◽  
Iron Oxide ◽  
Osmium Tetroxide ◽  
Lipid Vesicles ◽  
Negative Staining ◽  
Transmission Electron ◽  
Compositional Characterization

AbstractLipid-containing nanostructures, in the form of solid lipid nanoparticles or iron oxide nanoparticles (NPs) coated with a lipid shell, were used as case studies for assessing and optimizing staining for transmission electron microscopy structural and compositional characterization. These systems are of paramount importance as drug delivery systems or as bio-compatible contrast agents. In particular, we have treated the systems with a negative (phospshotungstic acid) or with a positive (osmium tetroxide) staining agent. For iron-oxide NPs coated with the lipid shell, negative staining was more efficient with respect to the positive one. Nevertheless, in particular cases the combination of the two staining procedures provided more complete morphological and compositional characterization of the particles.

Sepiolite at a locality in the Keuper Marl of the Midlands

1956 ◽  
Vol 31 (235) ◽  
pp. 328-332 ◽  
Author(s):  
P. S. Keeling
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Chemical Analysis ◽  
Diffraction Data ◽  
Ferric Oxide ◽  
X Ray Diffraction ◽  
X Ray

SummarySepiolite has been identified in the Keuper Marl at a Midlands locality by X-ray diffraction data, electron microscopy, differential thermal analysis, and chemical analysis. It has been calculated that a sample representing 30 ft. thickness of clay may contain as much as 39 % sepiolite. Apart from sepiolite, the Keuper Marl in the area examined consists mainly of mica, quartz, calcite, and ferric oxide.

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