scholarly journals Humus substances in the swamp ecosystems of taiga zone of Western Siberia

2021 ◽  
Vol 4 (4) ◽  
Author(s):  
T. T. Efremova ◽  
S. P. Efremov
Keyword(s):  
Humic Acids ◽  
Solid Phase ◽  
Structural Features ◽  
Taiga Zone ◽  
Left Bank ◽  
Wetland Ecosystems ◽  
Oxygenated Compounds ◽  
Humus Substances ◽  
Humus Type ◽  
Organic Carbon Stock

Eutrophic peatlands with a predominantly humate type of humus is dominated according to content of hydrophobic humus substances accumulated in the solid phase of peat. Oligotrophic peatlands with fulvate type of humus are characterized by minimal storages. Mesotrophic peatlands occupy a transitional position, both in terms of storage and in terms of the humus type – humate-fulvate. Hydrophilic components of the water phase are characterized by fulvate humus, regardless of the type of peatland, but differ in the proportion of the contribution of humus substances in the amphiphilic system of swamp ecosystems. It is the highest in the thickness of the oligotrophic peatland almost 31%, slightly lower in the mesotrophic – 25% and much less in the eutrophic – 6%. Structural features of macromolecules of humic acids of swamp waters of various genesis are determined. The humic acids of mesotrophic waters are adjacent to the group of reduced compounds, they are more enriched with aromatic structures and carboxyl groups in relation to oligotrophic waters. The humic acids of oligotrophic waters belong to a group of oxygenated compounds, have low enrichment of nitrogen, contain more methoxyl carbon and carbohydrates (polysaccharides). These structural features are caused by geochemistry of waters feeding the peatlands and specific mechanisms of humic acids synthesis on the swamps of different genesis. The volume of dissolved organic carbon stock from wetland ecosystems through system of taiga rivers of left bank of Middle Ob is 805 kt per year.

Synthesis of four new V1 antagonists of arginine-vasopressin (AVP) containing new thioacids at position 1 and their vasoconstrictor activity towards isolated mesenteric arterial vessels of rats

1991 ◽  
Vol 56 (2) ◽  
pp. 491-498 ◽  
Author(s):  
Bernard Lammek ◽  
Izabela Derdowska ◽  
Tomasz M. Wierzba ◽  
Witold Juzwa
Keyword(s):  
Peptide Synthesis ◽  
Arginine Vasopressin ◽  
Solid Phase ◽  
Structural Features ◽  
Phase Method ◽  
Competitive Antagonist ◽  
Vasoconstrictor Effect ◽  
Solid Phase Method

In an attempt to determine some of the structural features in position 1 that account for V1 antagonism, four new analogues of arginine-vasopressin were synthesized and the effect of the modifications on the vasoconstrictor activity was checked using isolated mesenteric arterial vessels of rats. The protected precursors required for these analogues were synthesized by a solid phase method of peptide synthesis. One of the reported analogues, namely [1-(4-mercapto-4-tetrahydrothiopyraneacetic acid)., 2-O-methyltyrosine, 8-arginine]vasopressin appears to be a potent competitive antagonist of the vasoconstrictor effect by AVP.

scholarly journals Structure-Acid Lability Relationship of N-alkylated α,α-dialkylglycine Obtained via a Ugi Multicomponent Reaction

Molecules ◽  
2021 ◽  
Vol 26 (1) ◽  
pp. 197
Author(s):  
Iván Ramos-Tomillero ◽  
Marisa K. Sánchez ◽  
Hortensia Rodríguez ◽  
Fernando Albericio
Keyword(s):  
Solid Phase Synthesis ◽  
Solid Phase ◽  
Structural Features ◽  
Amide Bond ◽  
Acidic Media ◽  
Phase Synthesis ◽  
Acyl Chains ◽  
Cyclic Compounds ◽  
Relationship Of ◽  
Fine Tune

Using the classical Ugi four-component reaction to fuse an amine, ketone, carboxylic acid, and isocyanide, here we prepared a short library of N-alkylated α,α-dialkylglycine derivatives. Due to the polyfunctionality of the dipeptidic scaffold, this highly steric hindered system shows an interesting acidolytic cleavage of the C-terminal amide. In this regard, we studied the structure-acid lability relationship of the C-terminal amide bond (cyclohexylamide) of N-alkylated α,α-dialkylglycine amides 1a–n in acidic media and, afterward, it was established that the most important structural features related to its cleavage. Then, it was demonstrated that electron-donating effects in the aromatic amines, flexible acyl chains (Gly) at the N-terminal and the introduction of cyclic compounds into dipeptide scaffolds, increased the rate of acidolysis. All these effects are related to the ease with which the oxazolonium ion intermediate forms and they promote the proximity of the central carbonyl group to the C-terminal amide, resulting in C-terminal amide cleavage. Consequently, these findings could be applied for the design of new protecting groups, handles for solid-phase synthesis, and linkers for conjugation, due to its easily modulable and the fact that it allows to fine tune its acid-lability.

scholarly journals Organic matter of soils and technogenic surface formations of residential areas of the city of Perm

2021 ◽  
Vol 5 (47) ◽  
pp. 27-27
Author(s):  
Natalia Moskvina ◽  
Igor Shestakov ◽  
Natalia Mitrakova
Keyword(s):  
Organic Matter ◽  
Urban Soils ◽  
Left Bank ◽  
Residential Areas ◽  
Humus Formation ◽  
Functional Zone ◽  
Humus Type ◽  
Reclaimed Soils ◽  
The City ◽  
Technogenic Surface Formations

On the territory of the left-bank part of Perm, the urban pedocomplexes (UPC) were distinguished as a combination of soil and technogenic surface formations on the same soil-forming rocks within a certain functional zone. Within the UPC, formed on eluvial-deluvial loams and clays in the zone of multi-storey buildings, the surface horizons of soils and TSF (technogenic surface formations) were studied. A change in the zonal trend of humus formation in reclaimed soils was observed as an increase in the content of organic matter, as well as in a change in the type of humus to the humate side. The conservation of zonal features of humus formation in non-purposefully recultivated urban soils and TSF was noted. It manifests in a low or medium content of organic carbon, the formation of a humate-fulvate type of humus. Keywords: URBAN ECOLOGY, URBAN SOILS, URBAN PEDOCOMPLEX, HUMUS, HUMUS TYPE, SOIL PROPERTIES

scholarly journals Engineering Geological and Geotechnical Approaches for the Construction of Powerhouse Cavern of Tehri Pumped Storage Plant (1000 MW) - A Case Study

2019 ◽  
Vol 24 ◽  
pp. 35-44
Author(s):  
Rajeev Prasad ◽  
Nishith Sharma
Keyword(s):  
Underground Structure ◽  
Shear Zones ◽  
Structural Features ◽  
Geological Mapping ◽  
Left Bank ◽  
Rock Composition ◽  
Northern India ◽  
Set Up ◽  
Pumped Storage

Construction of underground Cavern in the Himalayan region is full of challenges and uncertainties. Experience has shown that construction in Himalayan regions requires good understanding of geology, adequate site investigations, proper design and selection of suitable construction methodology and technology. The most commonly encountered geological problems during excavation of underground structure in Hydroelectric Projects are, Fault/Thrust/Shear Zones squeezing and swelling, wedge block failure etc. Tehri Pumped Storage Plant (PSP) is located at the left bank of river Bhagirathi in the state of Uttarakhand in Northern India. This case study indicates about the geological challenges faced and their remedial measures during the construction of Tehri PSP Powerhouse Cavern having dimension of 203m x 24m x 58m.3D-geological mapping with 1:100 scales was carried out in excavated central drift of powerhouse to evaluate the rock composition, behavior of rock mass, structural features and further investigation to finalize the layout and orientation. During the investigation Sheared Phyllite with bands of thinly Phyllite Quartzite rock were encountered in the end portion of central drift of powerhouse which had posed a mammoth challenge in designing the powerhouse cavern. Keeping in view the recommendations of geotechnical experts and the design consultants, decision were made to shift the cavern further by 50 m to avoid Sheared Phyllite bands. The shifting of cavern led to the reorientation of structures like control room, service bay and location of units etc. This paper briefly describes the Engineering Geological and Geotechnical set up of powerhouse with proper investigation approaches and excavation sequences highlighting the importance of orientation and Sheared Phyllite Zone.

Humus Substances and Soil Structure

2012 ◽  
Vol 63 (3) ◽  
pp. 31-36
Author(s):  
Erika Tobiašová ◽  
Juraj Miškolczi
Keyword(s):  
Humic Acids ◽  
Soil Structure ◽  
Size Fraction ◽  
Fulvic Acids ◽  
Optical Parameters ◽  
Humus Substances ◽  
Haplic Chernozems ◽  
Positive Correlations ◽  
The Stability

Abstract In this study, the soil structure of two soil types (Haplic Chernozems and Eutric Fluvisols) in four ecosystems (forest, meadow, urban and agro-ecosystem) with dependence on humus substances were compared. The stability of dry-sieved and waterresistant macro-aggregates and micro-aggregates with a dependence on the proportion of humus substance fractions was determined. Quantity of humus substances influenced mainly water-resistant aggregates. A positive correlation was recorded between size fraction of 2.3 mm and contents of humus substances (P < 0.01; r = +0.710) and fulvic acids (P < 0.05; r = +0.634), and negative correlation between size fraction of 0.5.1 mm and contents of humus substances (P < 0.05; r = -0.613) and fulvic acids (P < 0.01; r = -0.711). Humic acids influenced mainly the formation of dry-sieved aggregates and fulvic acids played an important role in micro-aggregate formation. The quality of humus substances influenced more intensively the formation of dry-sieved aggregates. There were positive correlations between optical parameters of humus substances and humic acids and larger dry-sieved aggregates (3.7 mm) and negative correlations with smaller (0.5.3 mm). The highest proportions of larger size of water-resistant aggregates (1. 20 mm) were in forest ecosystem, but smaller (0.25.1 mm) agreggates were dominated in agro-ecosystem.

Elemental composition and structural peculiarities of humic acids in bog waters of taiga zone

2014 ◽  
Vol 84 (13) ◽  
pp. 2562-2571 ◽  
Author(s):  
T. T. Efremova ◽  
S. P. Efremov ◽  
N. I. Pavlenko ◽  
N. G. Maksimov
Keyword(s):  
Elemental Composition ◽  
Humic Acids ◽  
Taiga Zone ◽  
Structural Peculiarities ◽  
Bog Waters

scholarly journals On-line solid phase microextraction derivatization for the sensitive determination of multi-oxygenated volatile compounds in air

2021 ◽  
Vol 14 (7) ◽  
pp. 4989-4999
Author(s):  
Esther Borrás ◽  
Luis A. Tortajada-Genaro ◽  
Milagro Ródenas ◽  
Teresa Vera ◽  
Thomas Speak ◽  
...  
Keyword(s):  
Solid Phase ◽  
Accurate Determination ◽  
High Volume ◽  
Automated System ◽  
Gas Chromatography Mass Spectrometry ◽  
Oxygenated Compounds ◽  
On Line ◽  
Secondary Aerosols ◽  
Hydroxy Aldehydes

Abstract. Multi-oxygenated volatile organic compounds are important markers of air pollution and precursors of ozone and secondary aerosols in both polluted and remote environments. Herein, their accurate determination was enhanced. The approach was based on an automated system for active sampling and on-fibre derivatization coupled with the gas chromatography–mass spectrometry (GC–MS) technique. The method capability was determined for different compound families, such as aldehydes, ketones, α-dicarbonyls, hydroxy-aldehydes, hydroxy-ketones, and carboxylic acids. A good accuracy (<7 %) was demonstrated from the results compared to Fourier-transform infrared spectroscopy (FTIR). Limits of detection (LODs) of 6–100 pptV were achieved with a time resolution lower than 20 min. The developed method was successfully applied to the determination of multi-oxygenated compounds in air samples collected during an intercomparison campaign (EUROCHAMP-2020 project). Also, its capability and accuracy for atmospheric monitoring was demonstrated in an isoprene ozonolysis experiment. Both were carried out in the high-volume outdoor atmospheric simulation chambers (EUPHORE, 200 m3). In summary, our developed technique offers near-real-time monitoring with direct sampling, which is an advantage in terms of handling and labour time for a proper quantification of trace levels of atmospheric multi-oxygenated compounds.

scholarly journals Structural features of non-cellular tissues of the human body during ochronosis

2020 ◽  
Vol 27 (4) ◽  
pp. 46-52
Author(s):  
Svetlana N. Shatokhina ◽  
Vadim V. Zar ◽  
Mikhail V. Zar ◽  
Vladimir N. Shabalin
Keyword(s):  
Synovial Fluid ◽  
Human Body ◽  
Genetic Disease ◽  
Structural Organization ◽  
Solid Phase ◽  
Biological Fluids ◽  
Clinical Signs ◽  
Polarized Light ◽  
Structural Features ◽  
Dark Field

With the help of special methods of dehydration, the features of the structural organization of the solid phase of biological fluids of a patient with a rare genetic disease ochronosis were revealed. Three biological fluids were taken as material for the study: urine, blood serum, and synovial fluid. For the transfer of biological fluids into a solid phase, the methods of cuneiform and marginal dehydration (technology Litos-System) were used. The structure of the solid phase of biological fluids was studied using stereomicroscopy in white and polarized light, as well as in a dark field. It was found that the structures of the solid phase of biological fluids reflect the main clinical signs of ochronosis, and also contains information about concomitant pathological processes. Specific structures of the solid phase of patients with ochronosis can be used as diagnostic markers of this disease.

scholarly journals Removal of Pyridine, Quinoline, and Aniline from Oil by Extraction with Aqueous Solution of (Hydroxy)quinolinium and Benzothiazolium Ionic Liquids in Various Ways

Separations ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 216
Author(s):  
Zhaojin Zhang ◽  
Yinan Li ◽  
Jing Gao ◽  
Alula Yohannes ◽  
Hang Song ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Ionic Liquids ◽  
Water Mass ◽  
Solid Phase ◽  
Kinetic Equations ◽  
Extraction Process ◽  
Structural Features ◽  
Back Extraction ◽  
Mass Ratio ◽  
N Removal

Based on above background, quinolinium, 8-hydroxy-quinolinium, and benzothiazolium ionic liquids, containing the acidic anions of methanesulfonate ([CH3SO3]−), phosphate ([H2PO4]−), p-toluenesulfonate ([p-TSA]−), and bisulfate ([HSO4]−) were synthesized. After comparison, the aqueous solution of benzothiazole bisulfate [HBth][HSO4] was selected as the most ideal extractant for removing pyridine and aniline. Meanwhile, benzothiazole bisulfate [HBth][HSO4] solution was found as the best one for removing quinoline from simulated oil. Then, the single stage extraction and two-step extraction were used in the extraction for the simulated oil containing pyridine, quinoline or aniline, and their mixture, respectively. Their denitrogenation performance on their N-removal effect was compared on the basis of structural features, and main extraction conditions were further investigated, including mass ratio of IL to water, mass ratio of IL to oil, and temperature. Furthermore, the extraction process was described by two kinetic equations. Recovery and reuse of IL were realized by back-extraction and liquid-liquid separation, and a related mechanism was speculated, according to all the experimental results. Finally, based on the developed method for preparing complex adsorbent tablets, corresponding immobilized IL was used to remove target objects, by solid phase extraction, in order to extend separation ways, which was more easily recovered after extraction.

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