Why soil aggregates are important in microbial ecology?4 answersSoil aggregates play a crucial role in microbial ecology by providing heterogeneous microhabitats that support diverse microbial communities and their interactions, influencing soil functions. Research indicates that soil aggregates create spatially distinct environments that shape the assembly of microbial communities within them. These aggregates act as protective niches for microbes, affecting nutrient cycling processes such as carbon, nitrogen, and phosphorus cycling. The size of soil aggregates influences the distribution and activity of microbial populations, with different aggregate sizes selecting for specific microbial taxa and functions. Moreover, the formation and stability of soil aggregates are influenced by microbial interactions, highlighting the intricate relationship between soil structure, microbial communities, and ecosystem functions.
What are the factors that affect the formation of aggregates?5 answersThe factors that affect the formation of aggregates include size-dependent diffusivity, rotational effects, settling under gravity, capillary pressure, interparticle attractive forces, charge heterogeneity, particle polarization, arbuscular mycorrhizal fungi (AMF), and pH value. Size-dependent diffusivity and rotational effects can slow down the growth rate of aggregates and decrease their fractal dimension. Capillary pressure can overwhelm repulsive electrostatic forces, leading to the assembly of aggregates that are out of thermal equilibrium. Charge heterogeneity and particle polarization can significantly alter the mechanical equilibrium of aggregates and hold particles together with electrostatic forces. AMF can influence the formation and stability of soil aggregates, with different AMF species having different effects. pH value can affect the morphology, physico-chemical properties, formation kinetics, and stability of amyloid and amyloid-like aggregates.
How are conducting polymers made?5 answersConducting polymers can be made through various preparative methods such as chemical and electrochemical synthesis. These methods involve factors like temperature, pH, concentration of monomers, and oxidants, which can affect the shape and physical-chemical properties of the polymers. Doping is a central process that governs the main properties of conducting polymers, including their conductivity. By doping conjugated polymers, their conductivity can increase significantly. Permanent doping can be achieved through processes like charge injection into the polymer chains accompanied by counterion adjunction for charge compensation. Additionally, conducting polymers can be synthesized by bonding an anionic polymer with terminal catechol and sulfonate moieties, as well as incorporating a cationic polymer like poly(3,4-ethylenedioxythiophene). These methods and strategies for modifying the properties of conducting polymers and their nanocomposites contribute to the progression and potential applications of these materials.
How do fibrillar aggregates form?5 answersFibrillar aggregates form through different mechanisms depending on the context. Lentil proteins (LP) can form fibrillar aggregates at acidic pH, which can stabilize oil-in-water emulsions and prevent coalescence and creaming. Single-stranded 12-mer deoxynucleotide oligomers (dN)12 can accelerate the formation of Cu/Zn superoxide dismutase (SOD1) aggregates under acidic conditions, with G-quadruplexes converting SOD1 into fibrillar aggregates. Random copolymers of amino acids can also form amyloid-like fibrils in aqueous solutions, demonstrating the high tolerance of amyloid aggregates to sequence irregularity. In concentrated solutions of amphiphilic macromolecules, a deterioration in solvent quality leads to the formation of intermolecular fibrillar helix bundles with approximately the same lengths and aggregation numbers. On a gold surface functionalized with an azide-terminated self-assembled monolayer, β-stranded peptides can self-assemble into antiparallel β-sheets to form fibrillar structures.
What are aggregates in OMIECs materials science?5 answersAggregates in OMIECs materials science refer to irregular clusters of many molecules that display modified or new properties compared to their individual molecular components. These aggregates are formed through the process of aggregation-induced emission, which has led to the concept of "aggregate science" to bridge the gap between molecules and aggregates. The study of aggregates has revealed unique structures and phenomena such as polymorphic aggregates, aggregation-induced symmetry breaking, and cluster excitons. Aggregates have been studied in various fields, including the development of artificial cell aggregates using microfluidic devices. Additionally, aggregates have been investigated in the context of asphaltenic aggregates in solution, where small-angle neutron scattering has been used to deduce their sizes and morphologies. Overall, the study of aggregates in OMIECs materials science has the potential to contribute to the development of new materials and technologies.
Are protein aggregates bigger than the proteins they are formed from?5 answersProtein aggregates can vary in size, ranging from nanometer aggregates (<100 nm) to sub-micron aggregates (100 nm - 1 μm) and micron aggregates (1 - 100 μm). The size of protein aggregates can be larger than the individual proteins they are formed from. For example, dimers comprising a large number of antibody molecules can have a diameter of up to 100 μm. Additionally, protein aggregates larger than hundreds of nanometers in diameter are difficult to physically fractionate. Therefore, protein aggregates can be significantly larger than the individual proteins they are formed from.