The role of fulvic acids in phosphorus sorption and release from mineral particles

1996 ◽  
Vol 34 (7-8) ◽  
pp. 259-265 ◽  
Author(s):  
Marija Kastelan-Macan ◽  
Mira Petrovic
Keyword(s):  
Interstitial Water ◽  
Concentration Level ◽  
Fulvic Acids ◽  
Competitive Sorption ◽  
Phosphorus Sorption ◽  
High Concentration ◽  
Mineral Particles ◽  
Phosphate Desorption

The competitive sorption of phosphates and marine fulvic acids on mineral particles (sand, calcite, bentonite and hematite) has been studied under simulated estuarine conditions. Afterwards, the release and desorption of bound phosphates by solutions containing dissolved fulvic acids was determined. It was found out that due to the favorable sorption of fulvic acids onto minerals studied binding of phosphate was significantly decreased. Desorption experiments showed that fulvic acids, present at high concentration level, similar to that in interstitial water of an oxygenated sediment, increase phosphate desorption by 10-20%.

Effect of High Salt Concentration on Ion Clustering and Transport in Polymer Solid Electrolytes: a Molecular Dynamics Study of PEO-LiTFSI

2018 ◽  
Author(s):  
Nicola Molinari ◽  
Jonathan P. Mailoa ◽  
Boris Kozinsky
Keyword(s):  
Polymer Electrolyte ◽  
Salt Concentration ◽  
Rational Design ◽  
Material System ◽  
Ion Dynamics ◽  
High Concentration ◽  
Anion Clusters ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

<div> <div> <div> <p>The model and analysis methods developed in this work are generally applicable to any polymer electrolyte/cation-anion combination, but we focus on the currently most prominent polymer electrolyte material system: poly(ethylene) oxide/Li- bis(trifluoromethane) sulfonamide (PEO + LiTFSI). The obtained results are surprising and challenge the conventional understanding of ionic transport in polymer electrolytes: the investigation of a technologically relevant salt concentration range (1 - 4 M) revealed the central role of the anion in coordinating and hindering Li ion movement. Our results provide insights into correlated ion dynamics, at the same time enabling rational design of better PEO-based electrolytes. In particular, we report the following novel observations. 1. Strong binding of the Li cation with the polymer competes with significant correlation of the cation with the salt anion. 2. The appearance of cation-anion clusters, especially at high concentration. 3. The asymmetry in the composition (and therefore charge) of such clusters; specifically, we find the tendency for clusters to have a higher number of anions than cations.</p> </div> </div> </div>

Effect of High Salt Concentration on Ion Clustering and Transport in Polymer Solid Electrolytes: a Molecular Dynamics Study of PEO-LiTFSI

2018 ◽  
Author(s):  
Nicola Molinari ◽  
Jonathan P. Mailoa ◽  
Boris Kozinsky
Keyword(s):  
Polymer Electrolyte ◽  
Salt Concentration ◽  
Rational Design ◽  
Material System ◽  
Ion Dynamics ◽  
High Concentration ◽  
Anion Clusters ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

<div> <div> <div> <p>The model and analysis methods developed in this work are generally applicable to any polymer electrolyte/cation-anion combination, but we focus on the currently most prominent polymer electrolyte material system: poly(ethylene) oxide/Li- bis(trifluoromethane) sulfonamide (PEO + LiTFSI). The obtained results are surprising and challenge the conventional understanding of ionic transport in polymer electrolytes: the investigation of a technologically relevant salt concentration range (1 - 4 M) revealed the central role of the anion in coordinating and hindering Li ion movement. Our results provide insights into correlated ion dynamics, at the same time enabling rational design of better PEO-based electrolytes. In particular, we report the following novel observations. 1. Strong binding of the Li cation with the polymer competes with significant correlation of the cation with the salt anion. 2. The appearance of cation-anion clusters, especially at high concentration. 3. The asymmetry in the composition (and therefore charge) of such clusters; specifically, we find the tendency for clusters to have a higher number of anions than cations.</p> </div> </div> </div>

scholarly journals Focused ultrasound in neuro-oncology: the role of the Focused Ultrasound Foundation in driving adoption and innovation

2021 ◽  
Author(s):  
Emily C. Whipple ◽  
Camille A. Favero ◽  
Neal F. Kassell
Keyword(s):  
Drug Delivery ◽  
Brain Tumors ◽  
Focused Ultrasound ◽  
Clinical Evidence ◽  
Neurological Injury ◽  
High Concentration ◽  
Potential Applications ◽  
Tumor Agent

Abstract Introduction Intra-arterial (lA) delivery of therapeutic agents across the blood-brain barrier (BBB) is an evolving strategy which enables the distribution of high concentration therapeutics through a targeted vascular territory, while potentially limiting systemic toxicity. Studies have demonstrated lA methods to be safe and efficacious for a variety of therapeutics. However, further characterization of the clinical efficacy of lA therapy for the treatment of brain tumors and refinement of its potential applications are necessary. Methods We have reviewed the preclinical and clinical evidence supporting superselective intraarterial cerebral infusion (SSJACI) with BBB disruption for the treatment of brain tumors. In addition, we review ongoing clinical trials expanding the applicability and investigating the efficacy of lA therapy for the treatment of brain tumors. Results Trends in recent studies have embraced the use of SSIACI and less neurotoxic chemotherapies. The majority of trials continue to use mannitol as the preferred method of hyperosmolar BBB disruption. Recent preclinical and preliminary human investigations into the lA delivery of Bevacizumab have demonstrated its safety and efficacy as an anti-tumor agent both alone and in combination with chemotherapy. Conclusion lA drug delivery may significantly affect the way treatment are delivered to patients with brain tumors, and in particular GBM. With refinement and standardization of the techniques of lA drug delivery, improved drug selection and formulations, and the development of methods to minimize treatment-related neurological injury, lA therapy may offer significant benefits for the treatment of brain tumors.

scholarly journals I Like the Way You Eat It: Lemur (Indri indri) Gut Mycobiome and Geophagy

2021 ◽  
Author(s):  
Luigimaria Borruso ◽  
Alice Checcucci ◽  
Valeria Torti ◽  
Federico Correa ◽  
Camillo Sandri ◽  
...  
Keyword(s):  
Plant Material ◽  
Soil Characteristics ◽  
Nutrient Supply ◽  
Fungal Species ◽  
High Concentration ◽  
Beneficial Role ◽  
Intimate Connection ◽  
Indri Indri ◽  
Lemur Species

AbstractHere, we investigated the possible linkages among geophagy, soil characteristics, and gut mycobiome of indri (Indri indri), an endangered lemur species able to survive only in wild conditions. The soil eaten by indri resulted in enriched secondary oxide-hydroxides and clays, together with a high concentration of specific essential micronutrients. This could partially explain the role of the soil in detoxification and as a nutrient supply. Besides, we found that soil subject to geophagy and indris’ faeces shared about 8.9% of the fungal OTUs. Also, several genera (e.g. Fusarium, Aspergillus and Penicillium) commonly associated with soil and plant material were found in both geophagic soil and indri samples. On the contrary, some taxa with pathogenic potentials, such as Cryptococcus, were only found in indri samples. Further, many saprotrophs and plant-associated fungal taxa were detected in the indri faeces. These fungal species may be involved in the digestion processes of leaves and could have a beneficial role in their health. In conclusion, we found an intimate connection between gut mycobiome and soil, highlighting, once again, the potential consequent impacts on the wider habitat.

Chemistry of oxylipin pathways in marine diatoms

2007 ◽  
Vol 79 (4) ◽  
pp. 481-490 ◽  
Author(s):  
Angelo Fontana ◽  
Giuliana d'Ippolito ◽  
Adele Cutignano ◽  
Antonio Miralto ◽  
Adrianna Ianora ◽  
...  
Keyword(s):  
Higher Plants ◽  
Larval Growth ◽  
Marine Macroalgae ◽  
High Concentration ◽  
Marine Diatoms ◽  
Fatty Acid Derivatives ◽  
The Family ◽  
Hydrolysis Of ◽  
Catalyzed Oxidation

Oxylipins are important signal transduction molecules widely distributed in animals and plants where they regulate a variety of events associated with physiological and pathological processes. The family embraces several different metabolites that share a common origin from the oxygenase-catalyzed oxidation of polyunsaturated fatty acids. The biological role of these compounds has been especially studied in mammalians and higher plants, although a varied and very high concentration of these products has also been reported from marine macroalgae. This article gives a summary of our results concerning the oxylipin chemistry of marine diatoms, a major class of planktonic microalgae that discourage predation from their natural grazers, zooplanktonic copepods, using chemical warfare. These apparently harmless microscopic cells produce a plethora of oxylipins, including short-chain unsaturated aldehydes, hydroxyl-, keto-, and epoxyhydroxy fatty acid derivatives, that induce reproductive failure in copepods through abortions, congenital malformations, and reduced larval growth. The biochemical process involved in the production of these compounds shows a simple regulation based on decompartmentation and mixing of preexisting enzymes and requires hydrolysis of chloroplast-derived glycolipids to feed the downstream activities of C16 and C20 lipoxygenases.

CONCENTRATION AND REGIONALIZATION OF AGRICULTURE IN THE WORLD

2021 ◽  
Vol XIII (1) ◽  
pp. 36-47
Author(s):  
Magdalena Golonko ◽  
Marcin Wysokiński ◽  
Arkadiusz Gromada
Keyword(s):  
South America ◽  
Agricultural Production ◽  
Concentration Level ◽  
Relative Increase ◽  
Animal Production ◽  
Agricultural Products ◽  
Plant Production ◽  
High Concentration ◽  
The World ◽  
Research Period

The main purpose of the article was to assess the regionalization of agricultural production in the world and the changes occurring in this aspect. The article presents the concentration level of agricultural production in the world by continent. The source of materials was data from FAOSTAT. The research period covered the years 2004 - 2016. In the analyzed period, the value of gross agricultural production doubled. Various trends were observed within the period studied. In the years 2004-2010, in all regions of the world, there was an increase in gross production of agriculture, while in the period 2010-2016 only in two – North America and Asia. It was noted that there was a high concentration of agricultural production, mainly concentrated in Asia and Europe. In the analyzed period, there was a relative increase in the share of agricultural production in Asia and South America as compared to other regions. Individual groups of agricultural products, such as cereals and animal production, were also analyzed. In both cases, concentration was different. The pace of concentration in animal production was higher than in plant production.

scholarly journals Evidence for biological shaping of hair ice

2015 ◽  
Vol 12 (14) ◽  
pp. 4261-4273 ◽  
Author(s):  
D. Hofmann ◽  
G. Preuss ◽  
C. Mätzler
Keyword(s):  
Organic Matter ◽  
Dead Wood ◽  
Complex Mixture ◽  
Fulvic Acids ◽  
Common Mechanism ◽  
Ice Growth ◽  
Physical Chemical ◽  
Broad Leaf ◽  
The Common

Abstract. An unusual ice type, called hair ice, grows on the surface of dead wood of broad-leaf trees at temperatures slightly below 0 °C. We describe this phenomenon and present physical, chemical, and biological investigations to gain insight in the properties and processes related to hair ice. Tests revealed that the biological activity of a winter-active fungus is required in the wood for enabling the growth of hair ice. We confirmed the fungus hypothesis originally suggested by Wegener (1918) by reproducing hair ice on wood samples. Treatment by heat and fungicide suppresses the formation of hair ice. Fruiting bodies of Asco- and Basidiomycota are identified on hair-ice-carrying wood. One species, Exidiopsis effusa (Ee), was present on all investigated samples. Both hair-ice-producing wood samples and those with killed fungus show essentially the same temperature variation, indicating that the heat produced by fungal metabolism is very small, that the freezing rate is not influenced by the fungus activity, and that ice segregation is the common mechanism of ice growth on the wood surface. The fungus plays the role of shaping the ice hairs and preventing them from recrystallisation. Melted hair ice indicates the presence of organic matter. Chemical analyses show a complex mixture of several thousand CHO(N,S) compounds similar to fulvic acids in dissolved organic matter (DOM). The evaluation reveals decomposed lignin as being the main constituent. Further work is needed to clarify its role in hair-ice growth and to identify the recrystallisation inhibitor.

scholarly journals Seasonal variation of mono- and sesquiterpene emission rates of Scots pine

2006 ◽  
Vol 3 (1) ◽  
pp. 93-101 ◽  
Author(s):  
H. Hakola ◽  
V. Tarvainen ◽  
J. Bäck ◽  
H. Ranta ◽  
B. Bonn ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Scots Pine ◽  
Early Summer ◽  
Emission Rates ◽  
High Concentration ◽  
Temperature Dependent ◽  
Emission Pattern ◽  
Defensive Role ◽  
Monoterpene Emission

Abstract. The seasonal variation of mono-and sesquiterpene emission rates of Scots pine was measured from April to October in 2004. The emission rates were measured daily in the afternoons with the exception of weekends. Emissions were measured from two branches; one of them was debudded in May (branch A), while the other was allowed to grow new needles (branch B). The monoterpene emission pattern remained almost constant throughout the measurement period, Δ3-carene being the dominant monoterpene (50-70% of the VOC emission). The standard monoterpene emission potential (30°C) was highest during early summer in June (the average of the two branches 1.35 µg g-1h-1) and lowest during early autumn in September (the average of the two branches 0.20 µg g-1h-1. The monoterpene emission potential of branch A remained low also during October, whereas the emission potential of branch B was very high in October. The sesquiterpenes were mainly emitted during mid summer, the dominant sesquiterpene being β-caryophyllene. Branch A had a higher sesquiterpene emission potential than branch B and the emission maximum occurred concomitant with the high concentration of airborne pathogen spores suggesting a potential defensive role of the sesquiterpene emissions. The sesquiterpene emissions were well correlated with linalool and 1,8-cineol emissions, but not with monoterpenes. Sesquiterpene and 1,8-cineol emissions were equally well described by the temperature dependent and the temperature and light dependent algorithms. This is due to the saturation of the light algorithm as the measurements were always conducted during high light conditions.

scholarly journals The role of a mid-air collision in drifting snow

2018 ◽  
Author(s):  
Shuming Jia ◽  
Zhengshi Wang ◽  
Shumin Li
Keyword(s):  
Friction Velocity ◽  
Global Climate ◽  
Three Dimensional ◽  
Particle Collision ◽  
High Concentration ◽  
Three Dimensional Model ◽  
Two Phase ◽  
Drifting Snow ◽  
Collision Mechanism

Abstract. Drifting snow, a common two-phase flow movement in high and cold areas, contributes greatly to the mass and energy balance of glacier and ice sheets and further affects the global climate system. Mid-air collisions occur frequently in high-concentration snow flows; however, this mechanism is rarely considered in current models of drifting snow. In this work, a three-dimensional model of drifting snow with consideration of inter-particle collisions is established; this model enables the investigation of the role of a mid-air collision mechanism in openly drifting snow. It is found that the particle collision frequency increases with the particle concentration and friction velocity, and the blown snow with a mid-air collision effect produces more realistic transport fluxes since inter-particle collision can enhance the particle activity under the same condition. However, the snow saltation mass flux basically shows a cubic dependency with friction velocity, which distinguishes it from the quadratic dependence of blown sand movement. Moreover, the snow saltation flux is found to be largely sensitive to the particle size distribution since the suspension snow may restrain the saltation movement. This research could improve our understanding of the role of the mid-air collision mechanism in natural drifting snow.

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