PRECIPITATION OF La (III), Sm (III) AND Tb (III) IONS BY ANIONOGENIC SURFACTANT ALKYBENZENESULFONIC ACID

The process of precipitation of La3+, Sm3+ and Tb3+ ions by anionic surfactant alkylbenzenesulfonic acid at various concentrations and ratios of components has been studied. The influence of the medium acidity and mixing time on the precipitation is considered. The resulting precipitates of rare earth elements ions with alkylbenzenesulfonic acid were studied by thermogravimetric, elemental and chemical analysis, and their composition was established. The conditional solubility products of the formed precipitates have been calculated. The optimal conditions for the precipitation of lanthanum (III), samarium (III) and terbium (III) ions with alkylbenzenesulfonic acid from aqueous solutions have been established.

The influence of cultivation conditions of promising Bacillus subtilis strains on their ability to produce antifungal metabolites

Antifungal compounds, including surfactin and iturin A, are accumulated by B. subtilis BZR336g strain at the cultivation temperature of 20.0-25.0 °C and the nutrient medium acidity pH8.0, for B. subtilis BZR517 strain these parameters are 30.0-35.0 °C and pH8.0-10.0, respectively.

Alpha-B-Crystallin Effect on Mature Amyloid Fibrils: Different Degradation Mechanisms and Changes in Cytotoxicity

Given the ability of molecular chaperones and chaperone-like proteins to inhibit the formation of pathological amyloid fibrils, the chaperone-based therapy of amyloidosis has recently been proposed. However, since these diseases are often diagnosed at the stages when a large amount of amyloids is already accumulated in the patient’s body, in this work we pay attention to the undeservedly poorly studied problem of chaperone and chaperone-like proteins’ effect on mature amyloid fibrils. We showed that a heat shock protein alpha-B-crystallin, which is capable of inhibiting fibrillogenesis and is found in large quantities as a part of amyloid plaques, can induce degradation of mature amyloids by two different mechanisms. Under physiological conditions, alpha-B-crystallin induces fluffing and unweaving of amyloid fibrils, which leads to a partial decrease in their structural ordering without lowering their stability and can increase their cytotoxicity. We found a higher correlation between the rate and effectiveness of amyloids degradation with the size of fibrils clusters rather than with amino acid sequence of amyloidogenic protein. Some external effects (such as an increase in medium acidity) can lead to a change in the mechanism of fibrils degradation induced by alpha-B-crystallin: amyloid fibers are fragmented without changing their secondary structure and properties. According to recent data, fibrils cutting can lead to the generation of seeds for new bona fide amyloid fibrils and accelerate the accumulation of amyloids, as well as enhance the ability of fibrils to disrupt membranes and to reduce cell viability. Our results emphasize the need to test the chaperone effect not only on fibrillogenesis, but also on the mature amyloid fibrils, including stress conditions, in order to avoid undesirable disease progression during chaperone-based therapy.

Catalytic Conversion of Cellulose to 5-hydroxymethylfurfural (5-HMF) Over Nano SO42--ZrO2 /MCM-41 Catalysts

A zirconium catalyst system supported on MCM-41 (S-Z) with various weight components (4-20 wt.%) Was synthesized by the sol-gel method. Structure and Morphology Catalysts were characterized by X-RD, TEM, BET, FT-IR and TPD-NH3 methods. In this catalyst, ZrO2 is highly dispersed on the surface of MCM-41 capillaries. Catalytic activity and selectivity were evaluated by the effectiveness of mild hydrothermal decomposition of cellulose to 5-hydroxymethyl furfural (5-HMF). The results show that a catalyst with medium acidity exhibits a high selectivity of 5-HMF. Keywords: S-Zr/MCM-41 materials, sol-gel methods, cellulose, 5-HMF.

The Relationship Between Acidity and Short-Term Student Performance on Exams

All students have to take exams at some point in their schooling careers and often in overwhelming amounts. With tests carrying great importance, students try to optimize their performance on these tests in a variety of ways. A widely-practiced strategy is eating peppermint or candy during the test in hopes of boosting brain performance. Peppermint has been known to stimulate olfactory receptors in humans. Similarly, acidity is an alternative powerful taste stimulant. Although acidity stimulates taste receptors and not olfactory receptors, taste and smell are very closely related which makes peppermint and acidity have similar overall effects. Since peppermint has shown improved memory and cognition in students, this study will now examine how acidity effects brain performance. This inquiry was investigated by giving 84 local high school students beverages of ranging acidity levels and soon after having them complete a timed, four-function math exam to test their brain performance. With average test scores of 38.62, 36.05, and 40.02 for the highest acidity, medium acidity, and lowest acidity beverage respectively with a control (no drink) average of 39.33, acidity does not appear to have an effect on student brain stimulation (p=.53). In conclusion, there was no statistically significant correlation between acidity and student brain function, but this was only a preliminary study and similar concepts should be further explored in the future.

Porphyrazines with annulated diazepine rings. 5. Near-IR-absorbing tetrakis(6,7-dihydro-1H-1,4-diazepino)porphyrazines and effects of acid solvation on their spectral properties

Novel porphyrazines bearing fused 6,7-dihydro-1H-1,4-diazepine rings were synthesized and their spectral response on the change of medium acidity was demonstrated.