Search results for "alkaline"

Alkaline hydrolysis/methylation-acetylation: a new technique for ultrastructural DNA cytochemistry.

1991

SUMMARY A new technique for the visualization of DNA-containing structures in electron microscopy is described. Samples of glutaraldehyde-fixed bone marrow from rats were subjected to alkaline hydrolysis to remove RNA and the phosphate of phospho-proteins, followed by a combined blockage of protein carboxyl and amino groups through methylation-acetylation. After uranyl acetate staining of epoxy-embedded ultrathin sections, chromatin from all cell types showed a highly selective and intense electron opacity. Staining methods for DNA were also positive in semithin sections. This simple procedure could be very useful in ultrastructural cytochemistry of DNA and chromatin.

Activation of Human Osteoblasts via Different Bovine Bone Substitute Materials With and Without Injectable Platelet Rich Fibrin in vitro

2021

IntroductionThe aim of the in vitro study was to compare the effect of four bovine bone substitute materials (XBSM) with and without injectable platelet-reach fibrin for viability and metabolic activity of human osteoblasts (HOB) as well as expression of alkaline phosphatase (ALP), bone morphogenetic protein 2 (BMP-2), and osteonectin (OCN).Materials and MethodsCerabone® (CB), Bio-Oss® (BO), Creos Xenogain® (CX) and MinerOss® X (MO) ± i-PRF were incubated with HOB. At day 3, 7, and 10, cell viability and metabolic activity as well as expression of ALP, OCN, and BMP-2, was examined.ResultsFor non-i-PRF groups, the highest values concerning viability were seen for CB at all time points. Pre-t…

Mechanical properties of materials obtained via alkaline activation of illite-based clays of Latvia

2015

Materials has been synthesized in the temperature range from 60-100 °C from two illite based clays of Latvia under activation of KOH and NaOH solutions (4-6 M). Compressive strength and apparent porosity were measured. The effect of concentration of KOH and NaOH solutions on the material mechanical properties was investigated by means of infrared spectroscopy (IR). Compressive strength data of the materials showed that via such activation could obtain building materials with good quality.

Effect of the Alkaline Cations on the Stability of the Model Polynucleotide Poly(dG-dC)·Poly(dG-dC)

2011

When the model polynucleotide poly(dG-dC)∙poly(dG-dC) [polyGC] is titrated with a strong acid (HCl) in unbuffered aqueous solutions containing the chlorides of the alkali metals in the concentration range 0.010 M-0.600 M, two transitions in the absorbance vs. pH plots are evidenced, characterized by the constants pK(a(₁)) and pK(a(₂)). The limiting values at infinite saline concentrations of these two constants, namely pK(∞)(a(₁)) and pK(∞)(a(₂)) obtained making use of the "one site saturation constant" equation or, in turn, of the double logarithmic plot: pK(a) vs. log([salt]⁻¹), exhibit a clear dependence on the nature of the cations. The effects of the different alkali cations on the pK(…

Ni and Ni-Pd nanostructures electrodes for water-alkaline electrolyses

2017

Hydrogen production by water electrolysis (WE) is a very promising technology because it is a pollution free-process specially if renewable energy are employed. Up to day, the cost of hydrogen production by WE is higher than other available technologies, making WE not competitive. Many efforts have been made to improve WE performance, through the use of electrodes made of transition metal alloys (Pt2Mo, TiPt) as a cathode or pyrochlore type oxide (Tl2RuxIr2-xO7) as an anode [1]. In the field of water-alkaline electrolyzer, the development of cheap nanoporous nickel electrodes with high electrocatalytic features is one of the potential approaches to increase the WE performance [2]., A facile…

Evolutionary Design Optimization of an Alkaline Water Electrolysis Cell for Hydrogen Production

2020

Hydrogen is an excellent energy source for long-term storage and free of greenhouse gases. However, its high production cost remains an obstacle to its advancement. The two main parameters contributing to the high cost include the cost of electricity and the cost of initial financial investment. It is possible to reduce the latter by the optimization of system design and operation conditions, allowing the reduction of the cell voltage. Because the CAPEX (initial cost divided by total hydrogen production of the electrolyzer) decreases according to current density but the OPEX (operating cost depending on the cell voltage) increases depending on the current density, there exists an optimal cu…

Die Herstellung einer molekulareinheitlichen Tetramethacrylsäure mittels verschiedener Matrizen. VI. Mitt. Modelle für Matrizenreaktionen

1968

Es wurde aus einer phenolischen Zweikernverbindung eine cyclische Verbindung IV hergestellt, die bei der alkalischen Hydrolyse eine molekulareinheitliche Tetramethacrylsaure (VII) und die phenolische Ausgangsverbindung gab. Die Synthese der gleichen Saure (VII) gelang auch mit strukturell verschiedenen Zweikernverbindungen, wenn nur bei den verwendeten Matrizen der innermolekulare Abstand der beiden phenolischen Hydroxylgruppen fur die Reaktion gunstig war. Alkaline hydrolysis of a cyclic compound (IV) which was prepared out of a dinuclear phenolic compound gave a molecularly homogeneous tetra-methacrylic acid (VII) and the original phenolic compound. The synthesis of the same acid could al…

1984

Alkaline hydrolyses of anionic phenyl esters such as 4-acetoxy-3-nitrobenzoic acid and 4-butyryloxy-3-nitrobenzoic acid were examined in the presence of cationic and polymeric liposomes, liposomes of low molecular weight compounds, and micelles. All the additives accelerate the reaction due to the hydrophobic interaction between substrates and additives and the electrostatic interaction both between substrates and additives and between OH− and additives. In the Arrhenius plots of the reactions catalyzed by the liposomes, discontinuous regions were observed due to the phase transition of liposomes from the gel state to the liquid crystal state. Activation parameters ΔH≠, ΔS≠ and ΔV≠ for thes…

In situ formation of pyronin dyes for fluorescence protease sensing

2017

International audience; We report a reaction-based strategy for the fluorogenic detection of protease activity. Based on the "covalent-assembly" probe design principle recently put forward by the Yang group for detection of Sarin related threats (J. Am. Chem. Soc., 2014, 136, 6594-6597), we have designed two unusual nonfluorescent caged precursors (mixed bis-aryl ethers) which are readily converted into a fluorescent unsymmetrical pyronin dye through a domino cyclisation-aromatisation reaction triggered by penicillin G acylase (PGA) or leucine aminopeptidase (LAP). Fluorescence-based in vitro assays and HPLCfluorescence/- MS analyses support the claimed activation mechanism whose the furthe…

Alkaline titrations of poly(dG-dC).poly(dG-dC): microemulsion versus solution behaviour

2007

PolyGC was titrated with a strong base in the presence of increasing concentrations of NaCl (from 0.00 to 0.60M) either in water solution or with the polynucleotide solubilized in the aqueous core of reverse micelles, i.e., the cationic quaternary water-in-oil microemulsion CTAB/n-hexane/n-pentanol/water. The results for matched samples in the two media were compared. CD and UV spectroscopies and, for the solution experiments, pH measurements were used to follow the course of deprotonation. In both media the primary effect of the addition of base was denaturation of the polynucleotide, reversible by back-titration with a strong acid. In solution, the apparent pK(a) of the transition decreas…