Search results for "SUBSTANCES"
showing 10 items of 1122 documents
Gelation of semiflexible polyelectrolytes by multivalent counterions
2012
Filamentous polyelectrolytes in aqueous solution aggregate into bundles by interactions with multivalent counterions. These effects are well documented by experiment and theory. Theories also predict a gel phase in isotropic rodlike polyelectrolyte solutions caused by multivalent counterion concentrations much lower than those required for filament bundling. We report here the gelation of Pf1 virus, a model semiflexible polyelectrolyte, by the counterions Mg(2+), Mn(2+) and spermine(4+). Gelation can occur at 0.04% Pf1 volume fraction, which is far below the isotropic-nematic transition of 0.7% for Pf1 in monovalent salt. Unlike strongly crosslinked gels of semiflexible polymers, which stif…
CO2 Fixation by Copper(II) Complexes of a Terpyridinophane Aza Receptor
2004
CO2 is fixed by a Cu2+ complex of a macrocyclic terpyridinophane ligand forming a carbamate group. Several features of the structure mimic the enzyme rubisco.
Stereoselective glycosylation of Alcohols and Silyl Ethers Using Glycosyl Fluorides and Boron Trifluoride Etherate
1985
The stereoselective glycosylation of alcohols and their silyl ethers has been achieved using O-alkyl-, O-acyl-, and acetal-protected glycosyl fluorides of the pyranose and furanose series and boron trifluoride etherate in CH2Cl2.
Studying the phosphoryl transfer mechanism of the
2019
Phosphofructokinases catalyze the ATP-dependent phosphorylation of fructose-6-phosphate and they are highly regulated.
Study of the role of sulfur functionalities in humic acids for uranium(VI) complexation
2009
Humic substances influence the speciation and migration behavior of toxic and radiotoxic metal ions, such as actinides, in the environment. Depending on their origin, humic substances contain different amounts of sulfur ranging from 0.1 to 3.6% and 0.5 to 1.43% in soil and aquatic humic substances, respectively [1]. Reduced, intermediately oxidized and highly oxidized sulfur functionalities occur in humic substances [1]. Although sulfur functionalities occur in small concentrations, they can play an important role in the complexation of selected metal ions. Knowledge about the impact of sulfur functionalities on the metal ion complexation by humic substances and their significance compared …
Formulation of Different Chitosan Hydrogels for Cartilage Tissue Repair
2014
Different formulations of Chitosan/sulphate and Chitosan/PEGDE were produced by physical and chemical reticulation to obtain hydrogels with better physiochemical properties. The hydrogels were analyzed – in terms of their non-toxicity, proliferative, differentiative, inflammatory and immunology responses. Commercial grade Chitosan (Sigma) was solubilized and purified by progressive filtrations. Then, the polymer was freeze-dried in a water soluble cationic form. A physical hydrogel was prepared by mixing a 3 % w/w water solution of the a.m. polymer with different stoichiometric ratios of (SO4=) 1/0.5;1/0.75;1/1 respectively. The hydrogels were cross-linked in multiwells. The chemical hydrog…
QUALITY OF GROUNDWATER AND AQUATIC HUMIC SUBSTANCES FROM MAIN RESERVOIRE OF GROUND WATER No. 333
2015
The conducted research included the estimation of the quality of groundwater from the Main Reservoir of Ground Water No. 333 area in Opole District, Poland. The groundwater in the analyzed region shows high diversity in quality. The main threat for the quality of water in this region is the human household activity. The main pollutants of groundwater are: dissolved phosphorus, nitrate and ammonium. The quality and quantity of dissolved humic substances in groundwater were also investigated. The results showed that the contents of water-extractable organic carbon varied. Presently, the analyzed groundwater is characterized by large differences in dissolved forms of organic carbon. During mig…
Microhydrological Niches in Soils: How Mucilage and EPS Alter the Biophysical Properties of the Rhizosphere and Other Biological Hotspots
2019
Plant roots and bacteria are capable of buffering erratic fluctuations of water content in their local soil environment by releasing a diverse, highly polymeric blend of substances (e.g. extracellular polymeric substances [EPS] and mucilage). Although this concept is well accepted, the physical mechanisms by which EPS and mucilage interact with the soil matrix and determine the soil water dynamics remain unclear. High-resolution X-ray computed tomography revealed that upon drying in porous media, mucilage (from maize [Zea mays L.] roots) and EPS (from intact biocrusts) form filaments and two-dimensional interconnected structures spanning across multiple pores. Unlike water, these mucilage a…
Blueprint for a minimal photoautotrophic cell: conserved and variable genes in Synechococcus elongatus PCC 7942.
2011
This is an Open Access article distributed under the terms of the Creative Commons Attribution License.-- et al.
The Leber congenital amaurosis protein AIPL1 and EB proteins co-localize at the photoreceptor cilium.
2015
The aim of this study was to investigate the interaction and co-localization of novel interacting proteins with the Leber congenital amaurosis (LCA) associated protein aryl hydrocarbon receptor interacting protein-like 1 (AIPL1).The CytoTrapXR yeast two-hybrid system was used to screen a bovine retinal cDNA library. A novel interaction between AIPL1 and members of the family of EB proteins was confirmed by directed yeast two-hybrid analysis and co-immunoprecipitation assays. The localization of AIPL1 and the EB proteins in cultured cells and in retinal cryosections was examined by immunofluorescence microscopy and cryo-immunogold electron microscopy.Yeast two-hybrid (Y2H) analysis identifie…