Cow-to-cow variation in nanocrystal synthesis: learning from technical-grade oleylamine

Many technical-grade reagents, including oleylamine, are broadly used as ligands in nanocrystal synthesis, allowing for cost-effective, and more environmentally friendly, preparation of materials in useful quantities. Impurities can represent 30% or more of these reagent blends, and have frequently emerged as substantial drivers of nanocrystal morphology, assembly, or other physical properties, making it important to understand their composition. Some functional alkyl reagents are derived from natural sources (e.g. often beef tallow, in the case of oleylamine), introducing alkyl chain structures very different than those that might be expected as side products of synthesis from pure feedstocks. Additionally, impurities can exhibit variations based on biological factors (e.g. species, diet, season). In biology, blends of alkyl chains allow for surprisingly sophisticated function of amphiphiles in the cell membrane, pointing to the possibility of similar control in synthetic materials if reagent composition were either better controlled or better understood. Here, we provide brief context on the breadth of roles technical-grade impurities have played in nanocrystal materials, followed by a perspective on oleylamine impurities, their physical properties, and their potential contributions to nanomaterial function.

GRAPEVINE VARIETY AUGUSTA BRED BY ARRIV&W – BRANCH OF FRARC FOR HIGH QUALITY WINE

The paper presents the technological study of red wine variety Augusta bred in Ya.I. Potapenko Institute for Viticulture and Winemaking. The research was carried out in the laboratory of winemaking technology in the conditions of micro-winemaking and semi-reproduction. The mass of one batch of grapes was 50–350 kg. Samples of natural dry, semi-sweet and liqueur wines were pre-pared. The main physical and chemical pa-rameters of wort and wine are determined. All of them corresponded to the Standard indicators. The organoleptic evaluation of wine materials showed that all the samples (dry, semi-sweet and liqueur) were distin-guished by a dark ruby color, had a bright, complex aroma, with tones of berries, and light shades of tea rose, and the high organo-leptic properties of the wines were increased when using bottle holding. According to the results of the research, conclusions were made about the feasibility of using the technical grade Augusta for the preparation of various types of wines (dry, semi-sweet and liqueur).

Evaluation of concurrent exposure of lower concentrations of lead and endosulfan on apoptosis by scatter pattern of flow cytometry

The effect of repeated exposure of lower doses of lead and endosulfan were evaluated on apoptosis in male wistar rats. Rats of group I served as untreated control. Group II received drinking water with lead as lead acetate @100 ppm (Pb100). Group III was given feed containing technical grade endosulfan @ 10 ppm (E10). Group IV was exposed to Pb (100) +E (10). Splenocytes were analysed for estimating apoptotic percentage in rats. The results suggest that apoptotic percentage was not changed in the lower doses of endosulfan and lead when administered alone and also in combination in the present study

The study of primary DNA damage in the bone marrow of mice under the combined action of pesticides

Introduction. The study of the potential negative effects of combinations of several pesticide active ingredients is an important and understudied area of toxicological and hygienic research. The initial phase of the genotoxicant action on the genetic structures in cells is the primary DNA damage, the identification of which makes it possible to assess the early stages of the genotoxic effect of xenobiotics and their mixtures. The DNA comet assay is widely used for these purposes. The aim of the research is to assess the primary DNA damage under the combined action of pesticides. Materials and methods. To assess DNA damage the experiments on CD-1 mice of both sexes were performed using alkaline comet analysis. The concentration of active products reacting with thiobarbituric acid (TBA) in the blood serum of white outbred rats was assessed as a marker of lipid peroxidation. Results. It was found that mixtures of 2,4-D-acid + glyphosate and thiram + carbendazim did not cause the formation of breaks and alkali-labile sites in the DNA of mice bone marrow cells. Exposure to the combination of the technical grade active ingredients captan and fludioxonil induced the breaks and alkali-labile sites in the DNA of animal bone marrow cells. The comparison of the genotoxicity assessment results obtained by the comet assay and results of analysis of the TBA-active product concentrations in the rat blood serum suggests that the observed primary DNA damage upon exposure to the captan and fludioxonil combination can be mediated by the induction of lipid peroxidation and subsequent interaction of the resulting products with nucleic acids. Conclusion. The results indicate that some pesticides in combination can damage hereditary material in mammalian cells. Therefore, in order to ensure the safe use of pesticides for public health it is necessary to take into account the data on the genotoxicity not only of individual pesticide technical grade active ingredients but also their combinations.

Transfluthrin eave-positioned targeted insecticide (EPTI) reduces human landing rate (HLR) of pyrethroid resistant and susceptible malaria vectors in a semi-field simulated peridomestic space

Background Volatile pyrethroids (VPs) are proven to reduce human–vector contact for mosquito vectors. With increasing resistance to pyrethroids in mosquitoes, the efficacy of VPs, such as transfluthrin, may be compromised. Therefore, experiments were conducted to determine if the efficacy of transfluthrin eave-positioned targeted insecticide (EPTI) depends on the resistance status of malaria vectors. Methods Ribbons treated with 5.25 g transfluthrin or untreated controls were used around the eaves of an experimental hut as EPTI inside a semi-field system. Mosquito strains with different levels of pyrethroid resistance were released simultaneously, recaptured by means of human landing catches (HLCs) and monitored for 24-h mortality. Technical-grade (TG) transfluthrin was used, followed by emulsifiable concentrate (EC) transfluthrin and additional mosquito strains. Generalized linear mixed models with binomial distribution were used to determine the impact of transfluthrin and mosquito strain on mosquito landing rates and 24-h mortality. Results EPTI treated with 5.25 g of either TG or EC transfluthrin significantly reduced HLR of all susceptible and resistant Anopheles mosquitoes (Odds Ratio (OR) ranging from 0.14 (95% Confidence Interval (CI) [0.11–0.17], P < 0.001) to 0.57, (CI [0.42–0.78] P < 0.001). Both TG and EC EPTI had less impact on landing for the resistant Anopheles arabiensis (Mbita strain) compared to the susceptible Anopheles gambiae (Ifakara strain) (OR 1.50 [95% CI 1.18–1.91] P < 0.001) and (OR 1.67 [95% CI 1.29–2.17] P < 0.001), respectively. The EC EPTI also had less impact on the resistant An. arabiensis (Kingani strain) (OR 2.29 [95% CI 1.78–2.94] P < 0.001) compared to the control however the TG EPTI was equally effective against the resistant Kingani strain and susceptible Ifakara strain (OR 1.03 [95% CI 0.82–1.32] P = 0.75). Finally the EC EPTI was equally effective against the susceptible An. gambiae (Kisumu strain) and the resistant An. gambiae (Kisumu-kdr strain) (OR 0.98 [95% CI 0.74–1.30] P = 0.90). Conclusions Transfluthrin-treated EPTI could be useful in areas with pyrethroid-resistant mosquitoes, but it remains unclear whether stronger resistance to pyrethroids will undermine the efficacy of transfluthrin. At this dosage, transfluthrin EPTI cannot be used to kill exposed mosquitoes.

Study of the impurities in technical-grade 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane by gas chromatography-mass spectrometry

Polymerization of 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane is the main method for manufacturing methylphenylsiloxane rubbers, and copolymerization of octamethylcyclotetrasiloxane and 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane is the main method for production of high- and low-molecular weight dimethylmethylphenylsiloxane rubbers. The molecular weight, viscosity, and other properties of the obtained polymers depend on the purity of cyclosiloxanes. The technology of 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane production by thermocatalytic decomposition of methylphenylsiloxanes in the presence of lithium hydroxide or lithium silanolate, followed by vacuum rectification, makes it possible to obtain a product containing 1,3,5,7-tetramethyl-1,3,5,7-tetraphenylcyclotetrasiloxanes, tetraphenyldimethyldisiloxane as impurities and trace amounts of phenyl-containing siloxanes of cyclic and linear structure. The impurities of polycyclic and polyhedral structures have not been previously described. In this study, the method of gas chromatography-mass spectrometry is used to analyze compounds that can be present as impurities in technical-grade 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane. The use of the previously described regularities of the fragmentation of siloxanes of different structures made it possible to identify a number of siloxanes which are absent in the NIST 11 mass spectra library. It is shown that polycyclic and polyhedral compounds containing methylsilsesquioxane units have a short fragmentation path. They are characterized by ionization with the elimination of the methyl group and benzene in case of two phenyl groups in the molecule. The siloxane skeleton of such cations is rather stable, so they more readily lose another methyl group thus transforming into double-charged cations. The impact of electron ionization on the molecules with siloxane units containing different organic substituents at silicon leads to randomization of those substituents and rearrangement of the siloxane skeleton. Analysis of the results revealed that silanes, siloxanes of linear, cyclic, polycyclic and polyhedral structures are present in technical grade 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane.

Assessing Missouri soybean fields for azoxystrobin resistant cercospora sojina

Successful management of Cercospora sojina, the causal agent of frogeye leaf spot, can be achieved through utilizing resistant varieties and fungicide applications. Fungicides in the quinone outside inhibitor (QoI) class are most effective in controlling C. sojina in the field. Unfortunately, azoxystrobin fungicide-resistant isolates of C. sojina have been recovered in many soybean growing areas of the U.S. Fungicide-resistant isolates of C. sojina were first detected in 2011 and 2012 in two counties in southeast Missouri, but no further assessment was conducted. In this study, 121 isolates were collected from 15 surveyed counties between 2019 and 2020 in an effort to understand the geographical distribution of fungicide-resistant C. sojina. Isolates were collected from fields based on the presence of frogeye leaf spot symptoms. Samples were brought to the laboratory and isolates were recovered from individual lesions. A fungicide sensitivity bioassay was conducted to determine which isolates were resistant to the QoI class of fungicides. The fungicide sensitivity bioassay consisted of full-strength PDA amended with technical grade azoxystrobin at five different concentrations and a no fungicide control. Out of 121 isolates, 81 were fungicide-resistant representing 13 of the 15 Missouri counties included in the survey. Notably, the northwest corner of Missouri had the highest concentration of fungicide-resistant isolates, consistent with the recent recovery of fungicide-resistant C. sojina isolates in Iowa and Nebraska. The widespread recovery of fungicide-resistant C. sojina in multiple counties throughout Missouri provides new insight into disease management in the state.