CHANGES IN THE VANADIUM MIGRATION FORMS ON GEOCHEMICAL BARRIERS IN THE RIVER-SEA MIXING ZONES

2021 ◽  
Author(s):  
Victoria Khoroshevskaya
Keyword(s):  
Software Package ◽  
Sorption Process ◽  
Biologically Active ◽  
Software Systems ◽  
River Waters ◽  
Geochemical Barriers ◽  
Physicochemical Processes ◽  
Estuarine Zone ◽  
Associative Models

The article is devoted to the study of vanadium, a metal capable of stimulating the growth of phytoplankton in situ and has the greatest biological activity in dissolved form. The pattern of an increase in the concentration of vanadium dissolved forms in the mixing zones during the transition from river waters to seawaters is known. In this article, we examine the behavior, ratio and change in the concentrations of vanadium dissolved and suspended forms during the passage of geochemical barriers. The estuarine zone of the Razdolnaya River–Amur Bay (Sea of Japan) is considered as "river-sea" mixing zone. Modelling of physicochemical processes was carried out using the Selector-S and MINTEQA2/PRODEFA2 software systems. Ion-associative models of sea and river water were built and the modelling of the process of their mixing was carried out using the Selector-S software package. The sorption process was simulated using the MINTEQA2/PRODEFA2 software package. The results of modelling physicochemical processes occurring at geochemical barriers help to understand the reasons for changes in concentrations, both total vanadium and biologically active dissolved vanadium forms, during the passage of geochemical barriers in the "river-sea" mixing zones. The results showed that there is a change in the dissolved forms of vanadium migration, their transformation and an increase in the concentration of dissolved forms of vanadium at the geochemical barrier

A Software Package for Simulating Physicochemical Processes and Properties of Working Fluids

2020 ◽  
Vol 67 (9) ◽  
pp. 591-603
Author(s):  
N. M. Kortsenshteyn ◽  
G. Ya. Gerasimov ◽  
L. V. Petrov ◽  
Yu. B. Shmel’kov
Keyword(s):  
Software Package ◽  
Working Fluids ◽  
Physicochemical Processes

scholarly journals Target screening of plant secondary metabolites in river waters by liquid chromatography coupled to high-resolution mass spectrometry (LC–HRMS)

2020 ◽  
Vol 32 (1) ◽  
Author(s):  
Mulatu Yohannes Nanusha ◽  
Martin Krauss ◽  
Carina D. Schönsee ◽  
Barbara F. Günthardt ◽  
Thomas D. Bucheli ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Surface Waters ◽  
High Resolution Mass Spectrometry ◽  
Water Cycle ◽  
Endocrine Disrupting Chemicals ◽  
Plant Secondary Metabolites ◽  
Biologically Active ◽  
Plant Metabolites ◽  
River Waters ◽  
Target Screening

Abstract Background Substantial efforts have been made to monitor potentially hazardous anthropogenic contaminants in surface waters while for plant secondary metabolites (PSMs) almost no data on occurrence in the water cycle are available. These metabolites enter river waters through various pathways such as leaching, surface run-off and rain sewers or input of litter from vegetation and might add to the biological activity of the chemical mixture. To reduce this data gap, we conducted a LC–HRMS target screening in river waters from two different catchments for 150 plant metabolites which were selected from a larger database considering their expected abundance in the vegetation, their potential mobility, persistence and toxicity in the water cycle and commercial availability of standards. Results The screening revealed the presence of 12 out of 150 possibly toxic PSMs including coumarins (bergapten, scopoletin, fraxidin, esculetin and psoralen), a flavonoid (formononetin) and alkaloids (lycorine and narciclasine). The compounds narciclasine and lycorine were detected at concentrations up to 3 µg/L while esculetin and fraxidin occurred at concentrations above 1 µg/L. Nine compounds occurred at concentrations above 0.1 µg/L, the Threshold for Toxicological Concern (TTC) for non-genotoxic and non-endocrine disrupting chemicals in drinking water. Conclusions Our study provides an overview of potentially biologically active PSMs in surface waters and recommends their consideration in monitoring and risk assessment of water resources. This is currently hampered by a lack of effect data including toxicity to aquatic organisms, endocrine disruption and genotoxicity and demands for involvement of these compounds in biotesting.

scholarly journals Imaging Sterols and Oxysterols in Mouse Brain Reveals Distinct Spatial Cholesterol Metabolism

2018 ◽  
Author(s):  
Eylan Yutuc ◽  
Roberto Angelini ◽  
Mark Baumert ◽  
Natalia Mast ◽  
Irina Pikuleva ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Mouse Brain ◽  
Brain Function ◽  
Mass Spectrometry Imaging ◽  
Cholesterol Metabolism ◽  
Biologically Active ◽  
Wild Type ◽  
Tissue Slices ◽  
The Brain

AbstractDysregulated cholesterol metabolism is implicated in a number of neurological disorders. Many sterols, including cholesterol and its precursors and metabolites, are biologically active and important for proper brain function. However, spatial cholesterol metabolism in brain and the resulting sterol distributions are poorly defined. To better understand cholesterol metabolism in situ across the complex functional regions of brain, we have developed on-tissue enzyme-assisted derivatisation in combination with micro-liquid-extraction for surface analysis and liquid chromatography - mass spectrometry to image sterols in tissue slices (10 µm) of mouse brain. The method provides sterolomic analysis at 400 µm spot diameter with a limit of quantification of 0.01 ng/mm2. It overcomes the limitations of previous mass spectrometry imaging techniques in analysis of low abundance and difficult to ionise sterol molecules, allowing isomer differentiation and structure identification. Here we demonstrate the spatial distribution and quantification of multiple sterols involved in cholesterol metabolic pathways in wild type and cholesterol 24S-hydroxylase knock-out mouse brain. The technology described provides a powerful tool for future studies of spatial cholesterol metabolism in healthy and diseased tissues.SignificanceThe brain is a remarkably complex organ and cholesterol homeostasis underpins brain function. It is known that cholesterol is not evenly distributed across different brain regions, however, the precise map of cholesterol metabolism in the brain remains unclear. If cholesterol metabolism is to be correlated with brain function it is essential to generate such a map. Here we describe an advanced mass spectrometry imaging platform to reveal spatial cholesterol metabolism in situ at 400 µm resolution on 10 µm tissue slices from mouse brain. We mapped, not only cholesterol, but also other biologically active sterols arising from cholesterol turnover in both wild type and mice lacking cholesterol 24-hydroxylase (Cyp46a1), the major cholesterol metabolising enzyme.

Development of Computer Vision Technique for in Situ Soil Characterization

1996 ◽  
Vol 1526 (1) ◽  
pp. 86-97 ◽  
Author(s):  
Roman D. Hryciw ◽  
Scott A. Raschke
Keyword(s):  
Computer Vision ◽  
Vision System ◽  
Cohesionless Soil ◽  
Software Systems ◽  
Small Scale ◽  
Second Phase ◽  
Video Images ◽  
Subsurface Soil ◽  
Different Levels

Construction and rehabilitation of highways, tunnels, and bridges require detailed information about subsurface stratigraphy. This study presents development of a new method for characterizing subsurface soil in situ using computer vision. Hardware and software systems are integrated to obtain the grain-size distribution (GSD) of subsurface soils continuously with depth and to identify small-scale subsurface anomalies. Research is being conducted in three phases. The first phase consists of measuring the GSD of detached cohesionless soil specimens in the laboratory from digital images obtained with a computer vision system (CVS). The second phase uses the CVS to develop image processing and analysis techniques to classify soil assemblies in the laboratory and identify subsurface anomalies by simulating the manner in which images will be acquired in situ. A texture analysis approach has been developed that can detect changes in stratigraphy. The technique has been successful in identifying different types of dry, uniformly graded soils. Finally, a subsurface vision probe is being designed and constructed that will capture video images at three different levels of magnification continuously with depth.

Highly Selective One-Pot Synthesis of Polysubstituted Isoflavanes using Styryl Ethers and Electron-Withdrawing ortho-Quinone Methides Generated In Situ

Synlett ◽  
2018 ◽  
Vol 30 (02) ◽  
pp. 189-192 ◽  
Author(s):  
Yujiro Hoshino ◽  
Kiyoshi Honda ◽  
Kenta Tanaka ◽  
Mami Kishimoto ◽  
Naoya Ohtsuka ◽  
...  
Keyword(s):  
Biologically Active ◽  
Quinone Methides ◽  
One Pot ◽  
One Pot Synthesis ◽  
Reaction Proceeds ◽  
Acidic Conditions ◽  
High Yields

A highly selective one-pot synthesis of polysubstituted isoflavanes has been developed. The reaction proceeds through the cycloaddition of methyl styryl ethers, derived from phenylacetaldehyde dimethyl acetals under acidic conditions, with electron-withdrawing ortho-quinone methides generated in situ. When phenylacetaldehyde dimethyl acetals were reacted with salicylaldehydes, the reaction proceeded smoothly to afford the corresponding isoflavanes stereoselectively in high yields and with excellent regioselectivities. The present reaction provides versatile access to functionalized isoflavanes, and constitutes a useful tool for the synthesis of biologically active molecules.

Minor enantiomer recycling – a strategy to improve enantioselectivity

2016 ◽  
Vol 88 (4) ◽  
pp. 309-316 ◽  
Author(s):  
Christina Moberg
Keyword(s):  
Catalytic Reaction ◽  
Enantiomeric Purity ◽  
Biologically Active Compounds ◽  
Starting Material ◽  
Biologically Active ◽  
Active Compounds ◽  
Enantioselective Reactions

AbstractIn enantioselective reactions, the major, desired enantiomer is commonly obtained along with the minor, undesired enantiomer. By continuous recycling of this undesired enantiomer back to starting material, products with improved enantiomeric purity can be obtained. Such in situ minor enantiomer recycling can be accomplished by coupling the catalytic reaction to an exergonic transformation of a sacrificial reagent. The method has been applied to the synthesis of O-acylated cyanohydrins, which serve as starting materials for a variety of biologically active compounds.

scholarly journals Simulating In-Situ Leaching Process Using Comsol Multiphysics

2014 ◽  
Vol 60 (3) ◽  
pp. 213-217 ◽  
Author(s):  
Bakhyt K. Mukhanov ◽  
Zhanar Zh. Omirbekova ◽  
Azamat K. Usenov ◽  
Waldemar Wójcik
Keyword(s):  
Numerical Simulation ◽  
Process Control ◽  
Technological Process ◽  
Software Package ◽  
Comsol Multiphysics ◽  
Hydrodynamic Characteristics ◽  
Process Variables ◽  
Leaching Process ◽  
Uranium In Situ Leaching

Abstract The paper deals with simulation of in-situ uranium leaching technological process, collecting data for forecasting and leaching process control. It provides numerical simulation of uranium in-situ leaching (ISL) using Comsol Multiphysics software package application. Previous studies evaluated main hydrodynamic characteristics of wells and reservoirs, such as the coefficient of resistance and the saturation recovery; while this paper is concerned with determining the changes in process variables in the wells during operation.

scholarly journals Rapid In Situ Enumeration of Physiologically Active Bacteria in River Waters using Fluorescent Probes.

1997 ◽  
Vol 12 (1) ◽  
pp. 1-8 ◽  
Author(s):  
NOBUYASU YAMAGUCHI ◽  
TAKEHIKO KENZAKA ◽  
MASAO NASU
Keyword(s):  
Fluorescent Probes ◽  
River Waters ◽  
Active Bacteria
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