Biological and economic evaluation of AMISTAR Gold fungicide against sunflower rust in the Lower Volga region

Rust is one of the most economically important foliar diseases of sunflower. The problem of sunflower disease control was considered. The article presents the results of a two-year experiment studying the efficiency of AMISTAR Gold fungicide, concentrated suspension (active ingredient: Azoxystrobin 125 g/L, Difenoconazole 125 g/L) in sunflower hybrids in the Lower Volga region. Flowerbud development stage was the best application timing for increasing productivity. Therefore, sunflower yield averaged 34 c/ha. The biological efficiency of the fungicide ranged from 85 to 90 %. The calculation of economic efficiency showed 145255 % profitability depending on the year.

Allelopathic and Herbicidal Effects of Crude Extract from Chromolaena odorata (L.) R.M.King and H.Rob. on Echinochloa crus-galli and Amaranthus viridis

The present study was aimed at investigating the allelopathic effects of a crude extract from Chromolaena odorata (L.) R.M.King and H.Rob. (Siam weed). The effects of 70% crude ethanol extract from the whole plant, leaf, stem, and root on the germination and growth of Echinochloa crus-galli and Amaranthus viridis seedlings were evaluated using Petri-dish tests under laboratory conditions. Crude extracts from the leaf showed the highest inhibitory activity. The leaf extract (OR) was further separated by sequential solvent extraction to provide hexane (HX), ethyl acetate (ET), and butanol (BU) fractions, which were also evaluated using Petri-dish tests. The hexane fraction was significantly the most active; therefore, it was selected for formulation in a concentrated suspension and tested for its herbicidal characteristics. The formulation showed greater early post-emergence than post- and pre-emergence activities, respectively. The physiological mechanism of the formulation was tested against E. crus-galli and showed that chlorophyll a and b and the carotenoid contents of the leaf dramatically decreased when the concentration was increased, suggesting its ability to disrupt the process of photosynthesis. As thiobarbituric acid reactive substances also occurred in the leaf of E. crus-galli, this suggests lipid peroxidation and cell disruption. These results represent the possibility that C. odorata extract contains inhibitory compounds with herbicidal activity and could be used as an early post-emergence herbicide for weed control.

Shielding surfaces from viruses and bacteria with a multifunctional coating

The spread of viral and bacterial pathogens mediated by contact with surfaces is a leading cause of infection worldwide. COVID-19 as well as the continuous rise of deaths associated with antibiotic-resistant bacteria highlights the need to impede surface-mediated transmission. We report a sprayable coating with an intrinsic ability to resist the uptake of bacteria and viruses from surfaces and droplets, such as those generated by sneezing or coughing. Our coating also provides an effective microbicidal functionality against bacteria, providing a dual barrier against pathogen uptake and transmission. This antimicrobial functionality is fully preserved following scratching and other induced damage to its surface or 9 days of submersion in a highly concentrated suspension of bacteria.

Characterization of particles and their relation with residual aluminum in water treated with pulsating floc blanket clarifiers and conventional clariflocculators using PACl

A pulsating floc blanket clarifier (PFBC) employing cyclic contractions and rarefactions to a bed of densely concentrated suspension of flocculated particles in fluidized state, was compared with conventional clariflocculator (CC) at pilot scale (8,000 L/day) in continuous mode of operation. For influent turbidity varied from 2 to 20 NTU, coagulation-flocculation behavior exhibited under the two fundamentally different treatment processes with PACl influenced inter-related performance parameters. The residual turbidity was found lower by 74%, flocs and fine colloids in suspension larger by 73 and 75% respectively, and the total and dissolved residual aluminum lower by 50 and 49% respectively on average for PFBC compared to CC. Particulate form comprised major fraction (≈72%) of total residual aluminum for both. PFBC abetted formation of a more consolidated floc structure which rendered the shape, size and morphology such that the settling velocity was 50% to 410% higher than that of the CC flocs. Reaction-limited aggregation (RLA) process and inter-particle bridging were dominant and the resulting floc structure and its formation mechanism have been presented.

Interphase interactions of hydrophobic powders based on methilsilica in the water environment

Using modern physicochemical research methods and quantum chemical modeling, the surface structure, morphological and adsorption characteristics, phase transitions in heterogeneous systems based on methylsilica and its mixtures with hydrophilic silica were studied. It is established that at certain concentrations of interfacial water, hydrophobic silica or their composites with hydrophilic silica form thermodynamically unstable systems in which energy dissipation can be carried out under the influence of external factors: increasing water concentration, mechanical loads and adsorption of air by hydrophobic component. When comparing the binding energies of water in wet powders of wettind-drying samples A-300 and AM-1, which had close values of bulk density (1 g/cm3) and humidity (1 g/g), close to 8 J/g. However, the hydration process of hydrophobic silica is accompanied by a decrease in entropy and the transition of the adsorbent-water system to a thermodynamically nonequilibrium state, which is easily fixed on the dependences of interfacial energy (S) on the amount of water in the system (h). It turned out that for pure AM-1 the interfacial energy of water increases in proportion to its amount in the interparticle gaps only in the case when h < 1 g/g. With more water, the binding energy decreases abruptly, indicating the transition of the system to a more stable state, which is characterized by the consolidation of clusters of adsorbed water and even the formation of a bulk phase of water. Probably there is a partial "collapse" of the interparticle gaps of hydrophobic particles AM-1 and the release of thermodynamically excess water. For mixtures of hydrophobic and hydrophilic silica, the maximum binding of water is shifted towards greater hydration. At AM1/A-300 = 1/1 the maximum is observed at h = 3g/g, and in the case of AM1/A-300 = 1/2 it is not reached even at h = 4 g/g. The study of the rheological properties of composite systems has shown that under the action of mechanical loads, the viscosity of systems decreases by almost an order of magnitude. However, after withstanding the load and then reducing the load to zero, the viscosity of the system increases again and becomes significantly higher than at the beginning of the study. That is, the obtained materials have high thixotropic properties. Thus, a wet powder that has all the characteristics of a solid after a slight mechanical impact is easily converted into a concentrated suspension with obvious signs of liquid.