scholarly journals Binding Characteristics and Dissociation Kinetics for Iron(II) Complexes with Seawater Extractable Organic Matter and Humic Substances in a Compost

2012 ◽  
Vol 28 (8) ◽  
pp. 819-821 ◽  
Author(s):  
Hisanori IWAI ◽  
Masami FUKUSHIMA ◽  
Mitsuo YAMAMOTO
Keyword(s):  
Organic Matter ◽  
Humic Substances ◽  
Dissociation Kinetics ◽  
Binding Characteristics ◽  
Extractable Organic Matter

ORGANIC MATTER CHARACTERISTICS OF UNDISTURBED AND CULTIVATED CHERNOZEMIC AND SOLONETZIC A HORIZONS

1979 ◽  
Vol 59 (4) ◽  
pp. 349-356 ◽  
Author(s):  
J. F. DORMAAR
Keyword(s):  
Organic Matter ◽  
Humic Substances ◽  
Chelating Resin ◽  
Anthropogenic Pressures ◽  
Organic C ◽  
Amide Bonds ◽  
Acid Ratio ◽  
Humic Materials ◽  
Fallow System ◽  
Extractable Organic Matter

Under a wheat-fallow system of farming practised on Brown, Dark Brown, and Black Chernozemic soils, on a Black Solodized Solonetz, and on Brown and Black Solods, organic C decreased by as much as 60%; the humic acid/fulvic acid ratio decreased little for the semiarid soils but up to 38% for the Black soils; ethanol/benzene-extractable organic matter increased by as much as 330%; chelating resin-extractable C increased by 27–115%; and total acidity of the extracted humic substances increased up to 36%. The ash contents of the humic substances from the Ah horizons were all less than 12%, whereas those of the Ap horizons varied between 20 and 28%. Apparent differences between the infrared spectra of the resin-extractable humic substances of the Ah and Ap horizons existed particularly near 2920 and 1550 cm−1 suggesting less aliphatic C-H and amide bonds. Anthropogenic pressures have wrought, therefore, distinct measurable qualitative changes, i.e., the general trend with cultivation was towards humic materials with a decreased proportion of side chain components, such as C-H and NH2 groups, but increased carboxyl group content.

ALKALINE CUPRIC OXIDE OXIDATION OF ROOTS AND ALKALINE-EXTRACTABLE ORGANIC MATTER OF CHERNOZEMIC SOILS

1979 ◽  
Vol 59 (1) ◽  
pp. 27-35 ◽  
Author(s):  
J. F. DORMAAR
Keyword(s):  
Organic Matter ◽  
Humic Substances ◽  
Ethyl Ether ◽  
Soluble Fraction ◽  
Cupric Oxide ◽  
Grass Species ◽  
Original Structure ◽  
Chromatographic Peak ◽  
Stipa Comata ◽  
Extractable Organic Matter

Alkaline cupric oxide oxidation was performed on roots of three grass species, on humic substances from three Chernozemic soils, and on three known compounds. The three grass species were Stipa comata Trin. & Rupr., Stipa spartea Trin. var. curtiseta Hitchc, and Festuca scabrella Torr., the three Chernozemic soils were Brown, Dark Brown and Black, and the three known compounds were vanillin, p-hydroxybenzaldehyde, and syringaldehyde. The intent of the study was to obtain a qualitative overview of the set of ethyl ether-soluble products. The gas chromatographic patterns were, therefore, qualitatively assessed and only some of the major peaks were tentatively identified. The ethyl ether-soluble fraction represented only up to 5.7% of the total root C. Most of the compounds identified in the root digests were also present in digests of the alkaline-soluble humic substances. There were quantitative differences for each chromatographic peak among root species, among time of sampling and growth location, and among extraction procedures of humic substances. The oxidation of the three known compounds in turn led to a number of compounds. The CuO-NaOH oxidation may thus cause alterations in similar compounds released from the original structure which will lead to either inflated or deflated yields of compounds that were part of the original structure.

scholarly journals Characterization of Soil Organic Matter Individual Fractions (Fulvic Acids, Humic Acids, and Humins) by Spectroscopic and Electrochemical Techniques in Agricultural Soils

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1067
Author(s):  
Aleksandra Ukalska-Jaruga ◽  
Romualda Bejger ◽  
Guillaume Debaene ◽  
Bożena Smreczak
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Humic Substances ◽  
Humic Acids ◽  
Agricultural Soils ◽  
Fulvic Acids ◽  
Sorption Properties ◽  
Aliphatic Chains

The objective of this paper was to investigate the molecular characterization of soil organic matter fractions (humic substances (HS): fulvic acids-FAs, humic acids-HAs, and humins-HNs), which are the most reactive soil components. A wide spectrum of spectroscopic (UV–VIS and VIS–nearIR), as well as electrochemical (zeta potential, particle size diameter, and polydispersity index), methods were applied to find the relevant differences in the behavior, formation, composition, and sorption properties of HS fractions derived from various soils. Soil material (n = 30) used for the study were sampled from the surface layer (0–30 cm) of agricultural soils. FAs and HAs were isolated by sequential extraction in alkaline and acidic solutions, according to the International Humic Substances Society method, while HNs was determined in the soil residue (after FAs and HAs extraction) by mineral fraction digestion using a 0.1M HCL/0.3M HF mixture and DMSO. Our study showed that significant differences in the molecular structures of FAs, Has, and HNs occurred. Optical analysis confirmed the lower molecular weight of FAs with high amount of lignin-like compounds and the higher weighted aliphatic–aromatic structure of HAs. The HNs were characterized by a very pronounced and strong condensed structure associated with the highest molecular weight. HAs and HNs molecules exhibited an abundance of acidic, phenolic, and amine functional groups at the aromatic ring and aliphatic chains, while FAs mainly showed the presence of methyl, methylene, ethenyl, and carboxyl reactive groups. HS was characterized by high polydispersity related with their structure. FAs were characterized by ellipsoidal shape as being associated to the long aliphatic chains, while HAs and HNs revealed a smaller particle diameter and a more spherical shape caused by the higher intermolecular forcing between the particles. The observed trends directly indicate that individual HS fractions differ in behavior, formation, composition, and sorption properties, which reflects their binding potential to other molecules depending on soil properties resulting from their type. The determined properties of individual HS fractions are presented as averaged characteristics over the examined soils with different physico-chemical properties.

Chemodiversity of water-extractable organic matter in sediment columns of a polluted urban river in South China

2021 ◽  
Vol 777 ◽  
pp. 146127
Author(s):  
Peng Zhang ◽  
Chun Cao ◽  
Ying-Hui Wang ◽  
Kai Yu ◽  
Chongxuan Liu ◽  
...  
Keyword(s):  
Organic Matter ◽  
South China ◽  
Urban River ◽  
Extractable Organic Matter ◽  
Water Extractable

scholarly journals Qualitative Prediction of Ligand Dissociation Kinetics from Focal Adhesion Kinase Using Steered Molecular Dynamics

Life ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 74
Author(s):  
Justin Spiriti ◽  
Chung F. Wong
Keyword(s):  
Molecular Dynamics ◽  
Drug Discovery ◽  
Focal Adhesion Kinase ◽  
Focal Adhesion ◽  
Early Stage ◽  
Steered Molecular Dynamics ◽  
Drug Binding ◽  
Binding Kinetics ◽  
Dissociation Kinetics ◽  
Binding Characteristics

Most early-stage drug discovery projects focus on equilibrium binding affinity to the target alongside selectivity and other pharmaceutical properties. Since many approved drugs have nonequilibrium binding characteristics, there has been increasing interest in optimizing binding kinetics early in the drug discovery process. As focal adhesion kinase (FAK) is an important drug target, we examine whether steered molecular dynamics (SMD) can be useful for identifying drug candidates with the desired drug-binding kinetics. In simulating the dissociation of 14 ligands from FAK, we find an empirical power–law relationship between the simulated time needed for ligand unbinding and the experimental rate constant for dissociation, with a strong correlation depending on the SMD force used. To improve predictions, we further develop regression models connecting experimental dissociation rate with various structural and energetic quantities derived from the simulations. These models can be used to predict dissociation rates from FAK for related compounds.

scholarly journals Using water hyacinth (Eichhornia crassipes) biomass and humic substances to produce urea-based multi-coated slow release fertilizer

Cellulose ◽  
2021 ◽  
Author(s):  
Iris Amanda A. Silva ◽  
Osmir Fabiano L. de Macedo ◽  
Graziele C. Cunha ◽  
Rhayza Victoria Matos Oliveira ◽  
Luciane P. C. Romão
Keyword(s):  
Organic Matter ◽  
Humic Substances ◽  
Natural Organic Matter ◽  
Nitrogen Fertilization ◽  
Water Hyacinth ◽  
Eichhornia Crassipes ◽  
Slow Release ◽  
Leaching Tests ◽  
Slow Release Fertilizer ◽  
Atmosphere System

AbstractUrea-based multi-coated slow release fertilizer was produced using water hyacinth, humic substances, and chitosan, with water rich in natural organic matter as a solvent. Elemental analysis showed that the nitrogen content of the fertilizer (FERT) was around 20%. Swelling tests demonstrated the effectiveness of the water hyacinth crosslinker, which reduced the water permeability of the material. Leaching tests showed that FERT released a very low concentration of ammonium (0.82 mg L−1), compared to the amount released from urea (43.1 mg L−1). No nitrate leaching was observed for FERT, while urea leached 13.1 mg L−1 of nitrate. In water and soil, FERT showed maximum releases after 30 and 40 days, respectively, while urea reached maxima in just 2 and 5 days, respectively. The results demonstrated the promising ability of FERT to reduce nitrogen losses, as well as to minimize environmental impacts in the soil–plant-atmosphere system and to improve the efficiency of nitrogen fertilization. Graphic abstract

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