Effects of Oleic Acid and Phospholipids on the Formation of Lecithin Organogel and Microemulsion

The formation of organogels and microemulsions of lecithin in the presence of a biocompatible cosurfactant, oleic acid, was studied. Low content of oleic acid ([oleic acid]/[lecithin] < 0.1) in the lecithin–oleic acid–dodecane–water system leads to an expansion of the region of existence and to a decrease in the viscosity of lecithin organogels. At high contents of oleic acid ([oleic acid]/[lecithin] > 0.6), low‐viscosity microemulsion exists in the system. Phosphatidylethanolamine, lysophosphatidylcholine, and other phospholipids that are present as impurities in the commercial samples of soybean lecithin can act as cosurfactants. For the first time, the formation of lecithin organogels in the systems containing commercial samples of soybean lecithin with phosphatidylcholine concentrations of 69.3 wt% (Lipoid S75) and 52.9 wt% (Lipoid S45) and saturated aliphatic hydrocarbons is demonstrated. The gelation is observed at T =25 °C in octane, decane, dodecane, and hexadecane for Lipoid S75 and in dodecane and hexadecane for Lipoid S45. A decrease in the degree of purification of lecithin leads to an expansion of the regions of existence of the organogels and to a reduction of their viscosity.     

A Time‐Symmetric Self‐Normalization Approach for Inference of Time Series

Self‐normalization has been celebrated as an alternative approach for inference of time series because of its ability to avoid direct estimation of the nuisance asymptotic variance. However, when being applied to quantities other than the mean, the conventional self‐normalizer typically exhibits certain degrees of asymmetry, an undesirable feature especially for time‐reversible processes. This paper considers a new self‐normalizer for time series, which (i) provides a time‐symmetric generalization to the conventional self‐normalizer, (ii) is able to automatically reduce to the conventional self‐normalizer in the mean case where the latter is already time‐symmetric to yield a unified inference procedure, and (iii) possibly leads to narrower confidence intervals when compared with the conventional self‐normalizer. For the proposed time‐symmetric self‐normalizer, we establish the asymptotic theory for its induced inference procedure and examine its finite sample performance through numerical experiments.     

Immunohistochemical analysis of S6K1 and S6K2 expression in human breast tumors

AIM: To express recombinant S6K2 in baculovirus expression system; to purify large quantities of recombinant S6K2 for biochemical studies; to generate and characterise specific MABs against recombinant S6K2; to study the patterns S6K1 and S6K2 expression and subcellular localization in normal, benign and malignant breast tissues. METHODS: Recombinant baculovirus, expressing wild type S6K2 was generated using Bac-to-Bac system (Invitrogen); recombinant S6K was purified from infected Sf9 cells using affinity purification approach; monoclonal antibodies against recombinant S6K2 were generated; the specificity of generated MABs towards recombinant and endogenous S6K2 were examined by ELISA, Western blotting, immunoprecipitation and immuhohistochemical staining; immunohistochemical detection of S6K1 and S6K2 in human breast tissues was performed using specific monoclonal antibodies towards S6K1 and S6K2. RESULTS: Large amounts of enzymatically active S6K2 were purified using baculovirus expression system; highly purified preparations of S6K2 were used to generate and characterize anti-S6K2 MABs; elevated levels of S6K1 and S6K2 were found in breast tumors when compared to normal breast tissues; S6K2 is frequently localized in the nuclei of adenocarcinoma tissues, but rarely in fibroadenoma or "normal" breast tissues. CONCLUSION: Production of recombinant S6K2 in large amount and generation of specific monoclonal antibodies towards S6K2 has provided us with excellent tools to study the function and regulation of this important signalling molecule in normal and cancer cells. Immunnohistochemical analysis of S6K1 and S6K2 expression in normal and malignant breast clearly indicates that both kinases are overexpressed in breast tumors, when compared to "normal" tissues. The retention of S6K2 in the nuclei of malignant cells may be caused by disregulation of nucleocytoplasmic shuttling and could subsequently affect cell growth and proliferation.     

Do challenge, task experience or computer familiarity influence the learning of historical chronology from virtual environments in 8-9 year old children?

Studies examined the potential use of VEs in teaching historical chronology to 127 children of primary school age (8-9 years). The use of passive fly-through VEs had been found, in an earlier study, to be disadvantageous with this age group when tested for their subsequent ability to place displayed sequential events in correct chronological order. All VEs in the present studies included active challenge, previously shown to enhance learning in older participants. Primary school children in the UK (all frequent computer users) were tested using UK historical materials, but no significant effect was found between three conditions (Paper, PowerPoint and VE) with minimal pre-training. However, excellent (error free) learning occurred when children were allowed greater exploration prior to training in the VE. In Ukraine, with children having much less computer familiarity, training in a VE (depicting Ukrainian history) produced better learning compared to PowerPoint, but no better than in a Paper condition. The results confirmed the benefit of using challenge in a VE with primary age children, but only with adequate prior familiarisation with the medium. Familiarity may reduce working memory load and increase children’s spatial memory capacity for acquiring sequential temporal-spatial information from virtual displays.     

Investigation of the Electronic Structure of Y2Cu2O5–xSx(x — 0.0, 0.25, 0.75) by X-ray Emission Spectroscopy and Xα Scattered Wave Calculation Methods

The investigation of the electronic properties of various copper oxides, containing structural fragments with specific Cu-O polyhedra, has been carried out. The electronic structure of Y₂Cu₂O_5–xS_x compounds (x = 0.0, 0.25, 0.75) has been studied by X-ray emission spectroscopy and the X_α scattered wave (SW) method of calculation. It is shown that substituting apical oxygen by sulfur in the squarepyramid fragments in high-temperature superconductors will result in a decrease of the density of hole carriers in "superconducting" grids of CuO₂ and in the suppression of superconductivity .     

A comparison of adsorption characteristics of various activated carbons

The physico-chemical characteristics of activated carbons obtained from different agricultural by-products by pyrolysis in a stream of water vapor have been investigated. It was established that under the same conditions of treatment the physico-chemical and adsorption characteristics of activated carbons depend on the composition of the initial raw materials. Activated carbon obtained from apricot stones has the best properties. It is characterized by a large specific surface area and micropores volume and high iodine and methylene blue adsorption activity. The activated carbons produced from cherry stones and grape seeds are characterized by predominating meso- and macropores structure. It can be supposed this is related to the larger content of lignin in those materials.     

Computational Design of Radical Recognition Assay with the Possible Application of Cyclopropyl Vinyl Sulfides as Tunable Sensors

The processes involving the capture of free radicals were explored by performing DFT molecular dynamics simulations and modeling of reaction energy profiles. We describe the idea of a radical recognition assay, where not only the presence of a radical but also the nature/reactivity of a radical may be assessed. The idea is to utilize a set of radical-sensitive molecules as tunable sensors, followed by insight into the studied radical species based on the observed reactivity/selectivity. We utilize this approach for selective recognition of common radicals—alkyl, phenyl, and iodine. By matching quantum chemical calculations with experimental data, we show that components of a system react differently with the studied radicals. Possible radical generation processes were studied involving model reactions under UV light and metal-catalyzed conditions.     

The application of the thermal stimulation in heavy oil recovery

The authors describe the technology of thermal stimulation of oil using standalone wind power plants. The thermal stimulation of the wellbore is the most effective method of reducing oil viscosity. The high viscosity of the reservoir oil leads to a significant reduction of water-free operation of the deposits, sweep efficiency reduction, and, as a consequence, results in uneven displacement front and advance to the local formation of dead zones.     

Microscopic studies of the influence of technological conditions on technical parameters of photopolymer flexographic plates

The quality of printing plates is one of the important factors influencing the accuracy of flexographic printed copies. The essential technological parameters determining the quality of flexographic plates comprise the dot gain, resolution, and profile of the printing elements. In this work, these parameters were studied using stereoscopic microscopy. These studies enabled us to determine the effect of technological parameters of photochemical preparation of flexographic plates on their resolution, tone transfer characteristics, and the profile of printing elements. It has been found that the quality of flexographic plates depends on the time of the preliminary and the main exposure of the photopolymer plates, the time of solvent washout, and the washout brushes height.     

The incorporation of challenge enhances the learning of chronology from a virtual display

In earlier studies investigating the learning of historical chronology, virtual fly-throughs were used in which successive historical events were represented by images on virtual screens, placed in temporal-spatial sequence. Undergraduate students benefited more than school-age children from virtual 3D (compared to 2D) training, perhaps because they took on the task as a challenge. In this study a modification of the earlier paradigm was used, in a game-like format, in which successive screens (paintings, representing epochs of art history) had to be memorised and anticipated during training, the participant’s score accumulating on the screen. Compared with PowerPoint and verbal-semantic training conditions, VE training resulted in more rapid learning, better recall of associated semantic information and error-free recall of the picture sequence. Possible applications of this paradigm for teaching were discussed.