A quantitative investigation into the effect of fixation, temperature and acid strength upon the Feulgen reaction

In the eukaryotic nucleus, DNA is packaged into nucleosomes, and the nucleosome chain folded into ‘30nm’ chromatin fibers. A number of different model structures, each with a specific location of nucleosomal and linker DNA have been proposed for the arrangment of nucleosomes within the fiber. We are exploring two strategies for testing the models by localizing DNA within chromatin: electron spectroscopic imaging (ESI) of phosphorus atoms, and osmium ammine (OSAM) staining, a method based on the DNA-specific Feulgen reaction.Sperm were obtained from Patiria miniata (starfish), fixed in 2% GA in 150mM NaCl, 15mM HEPES pH 8.0, and embedded In Lowiciyl K11M at -55C. For OSAM staining, sections 100nm to 150nm thick were treated as described, and stereo pairs recorded at 40,000x and 100KV using a Philips CM10 TEM. (The new osmium ammine-B stain is available from Polysciences Inc). Uranyl-lead (U-Pb) staining was as described. ESI was carried out on unstained, very thin (<30 nm) beveled sections at 80KV using a Zeiss EM902. Images were recorded at 20,000x and 30,000x with median energy losses of 110eV, 120eV and 160eV, and a window of 20eV.

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Shamanistic journeying: A quantitative investigation into altered states of consciousness using the Phenomenology of Consciousness Inventory

PsycEXTRA Dataset ◽

10.1037/e719122011-049 ◽

1995 ◽

Author(s):

Peggy Wright

Keyword(s):

Altered States Of Consciousness ◽

Altered States ◽

Quantitative Investigation ◽

States Of Consciousness

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Quantitative investigation on perceived anxiety and pain during the cervical cancer screening path

Minerva Psichiatrica ◽

10.23736/s0391-1772.18.01977-5 ◽

2018 ◽

Vol 59 (4) ◽

Author(s):

Matilde M. Canepa ◽

Alessandra Gobbi ◽

Gabriele Tibaldi ◽

Massimiliano Grassi

Keyword(s):

Cervical Cancer ◽

Cancer Screening ◽

Cervical Cancer Screening ◽

Quantitative Investigation

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Performance of Ag-HZSM-5 Zeolite Catalysts in n-heptane Conversion

Revista de Chimie ◽

10.37358/rc.17.1.5401 ◽

2017 ◽

Vol 68 (1) ◽

pp. 116-120

Author(s):

Iuliean Vasile Asaftei ◽

Neculai Catalin Lungu ◽

Lucian Mihail Birsa ◽

Ioan Gabriel Sandu ◽

Laura Gabriela Sarbu ◽

...

Keyword(s):

Aromatic Hydrocarbons ◽

Metal Content ◽

Pulse Method ◽

Acid Strength ◽

Strength Distribution ◽

Zeolite Catalysts ◽

Benzene Toluene ◽

Acid Strength Distribution ◽

Silver Cations ◽

Heptane Conversion

The conversion of n-heptanes into aromatic hydrocarbons benzene, toluene and xylenes (BTX), by the chromatographic pulse method in the temperature range of 673 - 823K was performed over the HZSM-5 and Ag-HZSM-5 zeolites modified by ion exchange with AgNO3 aqueous solutions. The catalysts, HZSM-5 (SiO2/Al2O3 = 33.9), and Ag-HZSM-5 (Ag1-HZSM-5 wt. % Ag1.02, Ag2-HZSM-5 wt. % Ag 1.62; and Ag3-HZSM-5 wt. % Ag 2.05 having different acid strength distribution exhibit a conversion and a yield of aromatics depending on temperature and metal content. The yield of aromatic hydrocarbons BTX appreciably increased by incorporating silver cations Ag+ into HZSM-5.

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Aromatization of C2-C6 Aliphatic Hydrocarbons on Copper-Containing ZSM-5 Zeolites

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19922553 ◽

1992 ◽

Vol 57 (12) ◽

pp. 2553-2560

Author(s):

Zdravka Popova ◽

Katia Aristirova ◽

Christo Dimitrov

Keyword(s):

Copper Content ◽

Acid Strength ◽

The State ◽

Aliphatic Hydrocarbons ◽

Bronsted Acid ◽

Ion Formation ◽

Brönsted Acid ◽

Wide Range ◽

Carbenium Ion ◽

Acid Centers

The aromatization of a wide range of model aliphatic and cycloaliphatic hydrocarbons (ethene, ethane, propene, n-hexane, 1-hexene, methylcyclopentane, cyclohexane, cyclohexene) on copper-containing NaZSM-5 and HZSM-5 zeolites has been investigated. It was established that the degree of aromatization is related to carbenium ion formation and depends on the acid strength and copper content of zeolite. Experiments with copper-containing samples reduced prior to use indicated the possibility to enhance the selectivity to aromatization. The change of the state of Cu2+ ions during catalytic experiments confirmed the assumption about participation of Cu0 simultaneously with the Bronsted acid centers in the dehydrogenation/hydrogenation steps.

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Preparation of Strong Acid Catalysts by Sulfate Treatment of Calcined Boehmite

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19922241 ◽

1992 ◽

Vol 57 (11) ◽

pp. 2241-2247 ◽

Cited By ~ 2

Author(s):

Tomáš Hochmann ◽

Karel Setínek

Keyword(s):

Catalytic Activity ◽

Surface Area ◽

Aluminum Sulfate ◽

Solid Acid ◽

Strong Acid ◽

Acid Strength ◽

Solid Acid Catalysts ◽

Acid Catalysts ◽

Preparation Methods ◽

Indicator Method

Solid acid catalysts with acid strength of -14.52 < H0 < -8.2 were prepared by sulfate treatment of the samples of boehmite calcined at 105-800 °C. Two preparation methods were used: impregnation of the calcined boehmite with 3.5 M H2SO4 or mixing of the boehmite samples with anhydrous aluminum sulfate, in both cases followed by calcination in nitrogen at 650 °C. The catalysts were characterized by measurements of surface area, adsorption of pyridine and benzene, acid strength measurements by the indicator method and by catalytic activity tests in the isomerization of cyclohexene, p-xylene and n-hexane. Properties of the catalysts prepared by both methods were comparable.

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