The effect of synthesis conditions and process parameters on aerogel properties

Aerogels are remarkable nanoporous materials with unique properties such as low density, high porosity, high specific surface area, and interconnected pore networks. In addition, their ability to be synthesized from various precursors such as inorganics, organics, or hybrid, and the tunability of their properties make them very attractive for many applications such as adsorption, thermal insulation, catalysts, tissue engineering, and drug delivery. The physical and chemical properties and pore structure of aerogels are crucial in determining their application areas. Moreover, it is possible to tailor the aerogel properties to meet the specific requirements of each application. This review presents a comprehensive review of synthesis conditions and process parameters in tailoring aerogel properties. The effective parameters from the dissolution of the precursor step to the supercritical drying step, including the carbonization process for carbon aerogels, are investigated from the studies reported in the literature.

QUALITY OF GARDEN STRAWBERRY FRUIT GROWN UNDER CONDITIONS OF TECHNOGENIC POLLUTION

The quality of fruit of garden strawberries grown on technogenically contaminated soils has been assessed. The highest level of copper and zinc in the fruit was recorded after broadcasting the recommended quantity of the fertiliser N90P60K30. Introduction of the sorbent ameliorant GREENODIN GRAY reduced the content of copper and zinc in the strawberries by 39 and 59% respectively. Researching the early-ripening strawberry cultivars Olviya and Rozana Kyivska has revealed varietal differences in the fruit’s trace element composition. Thus, it can be considered that selection of the proper cultivar is another effective method of obtaining environmentally safe products. Both strawberry cultivars under study were characterised by intense translocation of Cu and Zn into fruit. However, the Rozana Kyivska fruit contained 3 times more copper than the cultivar Olviya did. The zinc level, too, was higher in the Rozana Kyivska fruit (by 1.5 times). When introducing the recommended quantity of the fertiliser N90P60K30, the following criteria for the potential storability and transportability of the Olviya berries were recorded: resistance to phytopathogens, dense consistency of a berry, and the dry matter content 10.08%. As a result, the Olviya  berries  had the longest shelf life – 7 days, when stored in cooling chambers at 0.5°С and relative air humidity 90%. The sugar-acid index in these samples had the maximum value 6.9%, but the amount of vitamin C was at a minimum. This research has become the basis for practical application of a technology of growing strawberries of the cultivar Olviya. The technology involves broadcasting the fertiliser N90P60K30 together with the sorbent ameliorant GREENODIN GRAY (500 kg/ha) during the primary tillage, and introduction of N45P30K15 with irrigation water. The resulting Olviya berries are resistant to diseases and phytopathogenic damage during storage, have high nutritional value, and are less likely to accumulate ecotoxicants. The yield of berries in the first year of using the plantation was 6,200–6,500kg/ha. The content of nitrates and heavy metals in the berries did not exceed the maximum permissible concentration.

Micellization and Partition Equilibria in Mixed Nonionic/Ionic Micellar Systems: Predictions with Molecular Models

In practical applications, surfactant solutions are mostly used in mixtures of nonionic and ionic surfactants because they have improved characteristics compared to those of single surfactant solutions. By adjusting the composition of the micelles and the pH value, the solubilization of solutes can be enhanced. Nevertheless, the partitioning of solutes between nonionic/ionic mixed micelles and the aqueous phase is studied to a much lesser extent than for single surfactant solutions. Theoretical methods to predict partition equilibria in mixed micelles are of interest for screening studies. For those, the composition of the mixed micelle has to be known. Here we investigate mixtures of TX-114 (Triton X-114), Brij35 (C12E23), SDS (sodium dodecyl sulfate), and CTAB (cetyltrimethylammonium bromide). First, to investigate the surfactant compositions in the micelles, molecular dynamics (MD) self-assembly simulations were applied. Thereafter, the predictive COSMO-RS model, which applies the pseudophase approach, and its extension to anisotropic systems termed COSMOmic were compared for the prediction of partition equilibria in mixed micelles, where various molar ratios of the surfactants were considered. It could be demonstrated that both methods are applicable and lead to reasonable predictions for neutral molecules. However, taking into account the three-dimensional structure of the micelle is beneficial because the calculations with COSMOmic are in better agreement with experimental results. Because the partitioning behavior of ionizable molecules in mixed micelles is of particular interest, the partitioning of ionized isovanillin in mixed Brij35/CTAB micelles at different micelle compositions was calculated with COSMOmic. Using a thermodynamic cycle, the position-dependent pK_a of isovanillin within the micelle is calculated on the basis of COSMOmic free energy profiles. As a result, the protolytic equilibrium of isovanillin within the micelles can be taken into account, which is crucial for the reliable prediction of partition coefficients.

The structure of mental disorders in HIV-infected patients with syphilis

Introduction

There are no data in literature on mental disorders in HIV-infected patients with syphilis.

The objective of the study was to determine the structure of mental disorders in HIV-infected patients with syphilis.

Method

Sixty-five HIV-infected patients with syphilis were examined by a clinical method.

Results

The sample included 45 men (average age 32.09 ± 9.83) and 20 women (average age 31.7 ± 5.97). We divided the sample into three comparison groups (according to the importance of risk factors): women, men who have sex with men (MSM), and men who have sex with women (MSW).

Mental disorders were identified in most patients (83%). Opiate dependence (F11, ICD-10) was established in 55% of women (7.7% for MSW, 0% in MSM; P < 0.001). The dependence on multiple drug use (F19) was revealed with nearly the same frequency in women (25.0%) and in MSW (23.1%); but far less frequently in MSM (3.2%; P = 0.047). The dependence on stimulants (F15) was found in women (5.0%) and MSM (6.3%). The dependence on alcohol (F10) was more common among MSW (61.5%) and women (50.0%) (9.4% in MSM; P < 0.001). 20% of women had Depressive episode (F32). Adjustment disorders (F43) were found much more often in men (43.8% for MSM; 38.5% for MSW; 10% for women; P = 0.035). Personality disorders (F60) were found in all the groups.

Conclusions

We revealed a high incidence of addictions among women and MSW. Affective disorders were represented by depressive episode in women and adjustment disorders in men.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

A novel approach to alginate aerogels: carbon dioxide induced gelation

A novel process, carbon dioxide induced gelation, opens new pathways towards hydrogels and can be coupled with supercritical drying to produce aerogels.