scholarly journals Concentrations of Anthraquinone Glycosides of Rumex crispus during Different Vegetation Stages

1994 ◽  
Vol 49 (7-8) ◽  
pp. 404-406
Author(s):  
L. Ömür Demirezer
Keyword(s):  
Thin Layer ◽  
The Other ◽  
Rumex Crispus ◽  
Anthraquinone Glycosides

The anthraquinone glycoside contents of various parts of Rumex crispus L. (Polygonaceae) in different vegetation stages were investigated by thin layer chromatographic and spectro-photometric methods. The data showed that the percentage of anthraquinone glycoside in all parts of plant increased at each stage. Anthraquinone glycoside content was increased in leaf, stem, fruit and root from 0.05 to 0.40%, from 0.03 to 0.46%, from 0.08 to 0.34%, and from 0.35 to 0.91% respectively. From the roots of R. crispus, emodin-8-glucoside, RGA (isolated in our laboratory, its structure was not elucidated), traceable amount of glucofrangulin B and an unknown glycoside (Rf = 0.28 in ethyl acetate:m ethanol:water/100:20:10) was detected in which the concentration was increased from May to August. The other parts of plant contained only emodin-8-glucoside

Ultrastructural features of the sensori-motor cortex of the primate

1979 ◽  
Vol 285 (1006) ◽  
pp. 123-139 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Motor Cortex ◽  
Thin Layer ◽  
Liquid Helium ◽  
Thermal Insulation ◽  
Solid Surfaces ◽  
The Other ◽  
Experimental Chamber ◽  
Short Discussion ◽  
Inside Wall

cooled to 2°K or lower. Rollin (1936) found that the thermal insulation of vessels containing liquid helium was much worse below than above the A point. He explained his observation by assuming the existence of a thin layer of liquid helium on the inside wall of the connecting tube, and thought it probable that the change in thermal conductivity of this film at the A point gave rise to the anomalous effects observed. As the result of more recent (unpublished) experiments Rollin and Simon* have put forward the other explanation that the film creeps up the tube and evaporates eventually. It is obvious that all these phenomena may have a common explanation and it was the object of the experiments described in this paper and the following paper to investigate the behaviour of He 11 in contact with solid surfaces systematically. The phenomena had to be investigated from various aspects and this made experiments necessary which varied in purpose and character to some extent. For simplicity’s sake we will therefore give, together with the description of each experiment, a short discussion and summarize at the end of the second paper all results in a general discussion on the whole phenomenon. All experiments were carried out in the same cryostat; and for different experiments only the experimental chamber and the experimental arrangement in it were altered.

Analysis of Ochratoxins A and B and Their Esters in Barley, Using Partition and Thin Layer Chromatography. II. Collaborative Study

1973 ◽  
Vol 56 (4) ◽  
pp. 822-826
Author(s):  
Stanley Nesheim
Keyword(s):  
Thin Layer ◽  
Ochratoxin A ◽  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Ethyl Esters ◽  
The Other ◽  
Average Recovery ◽  
Confirmation Test ◽  
Two Samples ◽  
Layer Chromatography

Abstract To test the method of Nesheim et al., 6 samples wert; analyzed in 13 laboratories. The samples encompassed a blank and 5 samples containing one or more ochratoxins in the range 50–200 μg/kg. Two samples were spiked with the 4 ochratoxin standards and 3 were spiked with barley naturally contaminated with ochratoxin A. The confirmation of identity of ochratoxins A and B by preparation of their ethyl ester derivatives was also tested. The average recovery of standard ochratoxin A was 112% at levels of 45 and 90 μg/kg, with a 27.1% coefficient of variation calculated from analysis of variance, one analyst, one replicate. Similar satisfactory results were obtained for the ethyl esters of A and B at a level of 120 μg/kg. The results were unsatisfactory for ochratoxin B and for the esters of A and B at the 60 μg/kg level. The chemical confirmation test was satisfactory for both ochratoxins A and B. The method, including chemical confirmation, has been adopted as official first action as quantitative for ochratoxin A and qualitative for the other toxins.

Chromatographic Detection of Flavor Additives in Vanilla Extract

1964 ◽  
Vol 47 (3) ◽  
pp. 551-555
Author(s):  
S Kahan ◽  
J Fitelson
Keyword(s):  
Thin Layer ◽  
Collaborative Study ◽  
The Other ◽  
Sensitive Test ◽  
Ethyl Vanillin ◽  
Modified Method ◽  
Layer Method ◽  
Layer Technique ◽  
Thin Layer Method ◽  
Chromatographic Detection

Abstract Two chromatographic methods, one a thin-layer technique and the other paper chromatography, were developed for five flavoring additives and submitted to collaborative study. The thinlayer method gave good results and proved to be a rapid and sensitive test. However, some of the features of the method required further study to improve the identification of the separated spots. A better test for coumarin and another solvent giving greater separation between the ethyl vanillin and veratraldehyde spots were developed. The modified method has been recommended for adoption as official, first action. Some analysts attained good results with the paper chromatographic test; others, even experienced analysts, got poor results. Some of the difficulty was traced to variations in composition of reagents, but the method needs further study to standardize conditions. This method was not recommended for adoption. The proposed chromatographic thin-layer method offers a rapid means of detecting ethyl vanillin, veratraldehyde (methyl vanillin), coumarin, piperonal (heliotropin), and vanitrope (propenyl guaethol).

Sugar-meal sources used by female black flies (Diptera: Simuliidae): a four-habitat study

1997 ◽  
Vol 75 (7) ◽  
pp. 1066-1072 ◽  
Author(s):  
Steven G. Burgin ◽  
Fiona F. Hunter
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
The Other ◽  
Black Flies ◽  
Layer Chromatography ◽  
Provincial Park

Adult black flies were sampled by sweep-netting vegetation in four habitats within Algonquin Provincial Park, Ontario: Davies Bog, the airfield, deciduous habitat, and coniferous habitat. Sugars in the crops and midguts of female flies (n = 773) were tested by thin-layer chromatography to determine whether the flies had fed on nectar or homopteran honeydew. Melezitose and stachyose were used as honeydew-indicator sugars. For Simulium venustum, it was found that significantly fewer black flies (19%) from the airfield contained honeydew sugars than black flies from the other three sites (34% from Davies Bog; 36% from deciduous habitat; 25% from coniferous habitat). We argue that black flies will feed on nectar or honeydew according to availability.

scholarly journals 5α-Androstane-3α,17β-Diol Is Formed in Tammar Wallaby Pouch Young Testes by a Pathway Involving 5α-Pregnane-3α,17α-Diol-20-One as a Key Intermediate

Endocrinology ◽  
2003 ◽  
Vol 144 (2) ◽  
pp. 575-580 ◽  
Author(s):  
Jean D. Wilson ◽  
Richard J. Auchus ◽  
Michael W. Leihy ◽  
Oleg L. Guryev ◽  
Ronald W. Estabrook ◽  
...  
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Reductase Inhibitor ◽  
Tammar Wallaby ◽  
The Other ◽  
Synthetic Pathway ◽  
D 20 ◽  
17 Hydroxyprogesterone ◽  
Layer Chromatography

The synthetic pathway by which 5α-androstane-3α,17β-diol (5α-adiol) is formed in the testes of tammar wallaby pouch young was investigated by incubating testes from d 20–40 males with various radioactive precursors and analyzing the metabolites by thin-layer chromatography and HPLC. [3H]Progesterone was converted to 17-hydroxyprogesterone, which was converted to 5α-adiol by two pathways: One involves the formation of testosterone and dihydrotestosterone as intermediates, and the other involves formation of 5α-pregnane-3α,17α-diol-20-one (5α-pdiol) and androsterone as intermediates. Formation of 5α-adiol from both [3H]testosterone and [3H]progesterone was blocked by the 5α-reductase inhibitor 4MA. The addition of nonradioactive 5α-pdiol blocked the conversion of [3H]progesterone to 5α-adiol, and [3H]5α-pdiol was efficiently converted to androsterone and 5α-adiol. We conclude that expression of steroid 5α-reductase in the developing wallaby testes allows formation of 5α-reduced androgens by a pathway that does not involve testosterone as an intermediate.

The effect of intracellular geometry on auxin transport. I. Centrifugation experiments

1981 ◽  
Vol 214 (1194) ◽  
pp. 53-67 ◽  
Keyword(s):  
Thin Layer ◽  
High Velocity ◽  
Plant Hormone ◽  
Auxin Transport ◽  
The Other ◽  
Permeability Barrier ◽  
Cell Geometry ◽  
Internal Cell ◽  
A Cell ◽  
High Concentrations

When coleoptiles are centrifuged, the velocity of transport of the plant hormone auxin is dramatically altered. I show here that this may be due to changes in internal cell geometry. The tonoplast, the membrane surrounding the vacuole, may present a substantial permeability barrier for the diffusion of auxin. After centrifugation, the cytoplasm sediments to one end of the cell, displacing the vacuole to the other. If auxin, on entering the cell, must first accumulate in a mass of cytoplasm before crossing the tonoplast, the velocity will be lowered. If, on the other hand, there is only a thin layer of cytoplasm where auxin enters, high concentrations will quickly build up and enable auxin to cross the tonoplast, giving a high velocity. This would explain why centrifugation in a basal direction increases velocity, while apical centrifugation de­creases it. If this explanation is correct, and if the tonoplast constitutes an appreciable permeability barrier, then the position of the vacuole may strongly influence the flux of auxin inside a cell. I show in the adjoining paper that this can explain the changed transport pattern seen during the geotropic response.

scholarly journals Determination of conversion rate values to characterise the ethanol production of the Kluyveromyces marxianus CBS712 fungus branch

2010 ◽  
pp. 23-27
Author(s):  
Éva Erdei ◽  
István Pócsi ◽  
Mónika Molnár ◽  
Gyöngyi Gyémánt ◽  
János Nagy
Keyword(s):  
Thin Layer ◽  
Ethanol Production ◽  
Kluyveromyces Marxianus ◽  
Conversion Rate ◽  
The Other ◽  
Conversion Rates ◽  
Residual Glucose ◽  
Oxidase Enzyme ◽  
Layer Chromatography

The ethanol production of the Kluyveromyces marxianus CBS712 strain was investigated among different kind of condition. We defined the conversion rate in order to know the efficiency of the ethanol production. To determine this value, it is crucial to characterize the residual glucose concentracio. We chose two method to determine the amount of residual glucose. The first method is the thin layer chromatography (TLC) and the second method is the method of the glucose-oxidase enzyme. We found that the TLC method is reliable than the other method. The conversion rates were determined from these values and the ethanol values. The maximal ethanol production of the characterized Kluyveromyces marxianus CBS712 strain (5.6% (v/v) ethanol at 45 °C, 55.3% conversion rate) is comparable to those strains which are applied in industrial ethanol production nowadays.

Platelet Factor 3 Activity in Washed Platelets

1973 ◽  
Vol 30 (03) ◽  
pp. 557-566 ◽  
Author(s):  
S Renaud ◽  
P Gautheron ◽  
H Rosenstein
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Platelet Rich Plasma ◽  
The Other ◽  
Slow Speed ◽  
Platelet Factor ◽  
Platelet Poor Plasma ◽  
Platelet Counts ◽  
Edta Solution ◽  
Layer Chromatography

SummaryPlatelets collected with an EDTA solution and simply washed in an incomplete Tyrode’s presented clotting times in the recalcification (man and rat) and the Stypven (rat) tests that were practically identical to those of the PRP when slow speed centrifugation was used (800 G in man, 1000 G in rat). This was demonstrated, in 6 pools of 5 rats each and in 6 men, by comparing the clotting activity of the citrated platelet-rich plasma to that of the platelets washed and resuspended in the citrated platelet-poor plasma, for platelet counts ranging from 1 × 105 to 10 × 105/mm3. In contrast, centrifugation of platelets at 3000 G markedly affected these clotting activities, as was shown in an additional study comprising 6 pools of 3 rats.Finally, the clotting activity of platelets totally disrupted by sonication appears to be identical quantitatively in both man and rats to that of the total phospholipids extracted from these platelets and separated from the other lipids by thin-layer chromatography and resuspended in plasma by sonication.

Proposed Standard Methods for Ink Identification

1975 ◽  
Vol 58 (1) ◽  
pp. 122-125 ◽  
Author(s):  
Jerry D Kelly ◽  
Antonio A Cantu
Keyword(s):  
Thin Layer ◽  
The Other ◽  
Chemical Methods ◽  
Standard Methods ◽  
Ink Analysis ◽  
Spot Tests ◽  
Physical And Chemical

Abstract Two methods are presented for the identification of ink, both of which are currently being used by laboratories involved in ink analysis. Both methods incorporate physical and chemical procedures. The differences are primarily in chemical methods involving spot tests and thin layer chromatographic (TLC) techniques. Furthermore, one method utilizes spectrophotometric scanning of the TLC plate whereas the other method utilizes solution spectrophotometry. It is recommended that both methods be evaluated by several laboratories.

The reaction sequence and microstructure evolution of an MgB2 layer during ex situ annealing of amorphous boron film

2004 ◽  
Vol 19 (2) ◽  
pp. 409-412 ◽  
Author(s):  
Hyun-Mi Kim ◽  
Sung-Soo Yim ◽  
Ki-Bum Kim ◽  
Dae-Hwan Kang ◽  
Seung-Hyun Moon ◽  
...  
Keyword(s):  
Thin Layer ◽  
Microstructure Evolution ◽  
Growth Process ◽  
Nucleation And Growth ◽  
The Other ◽  
Ex Situ ◽  
Amorphous Boron ◽  
Reaction Sequence ◽  
Initial Stage ◽  
Polycrystalline Form

The reaction sequence and microstructure evolution of a crystalline MgB2 layer were examined during ex situ annealing of evaporated amorphous boron (a-B) with Mg vapor. Mg was found to migrate rapidly into the a-B layer in the initial stage of reaction with a uniform concentration of about 12 at.%. A thin layer of crystalline MgO was observed at the interface between a-B and the Al2O3 substrate. It was identified that an MgB2 layer started to form at the surface by the nucleation and growth process in polycrystalline form. It appears that there exists two distinct growth fronts in the MgB2 layer: one lying at the surface and the other lying at the interface between the MgB2 layer and the a-B. The microstructural evolution of this layer showed significant differences depending on the location of these two growth fronts.

Sign in / Sign up

Export Citation Format

Share Document