Hybrid Sol-Gel Matrices Doped with Colorimetric/Fluorimetric Imidazole Derivatives

Organic-inorganic hybrids (OIH) are materials that can be easily synthesized by the sol-gel method and combine the advantages of organic and inorganic moieties within a single polymeric matrix. Imidazole derivatives are versatile organic compounds that can change their optical properties with the variation of pH due to the protonation or deprotonation of the nitrogen atoms. This work reports the preparation of different OIHs doped with different contents of two imidazole compounds (3a,b). The obtained materials were characterized structurally by FTIR, and the dielectric properties were studied by electrochemical impedance spectroscopy. The optical properties were studied by UV-Vis absorption and fluorescence spectroscopies. The FTIR analysis showed that the presence of the imidazole does not change the structural properties of the matrices. The normalized resistance values obtained for the doped matrices ranged between 8.57 and 9.32 Ω cm2, all being higher than the undoped matrix. The σ ranged between 9.49 and 10.28 S cm−1, being all higher than the pure OIH samples. Compound 3a showed a maximum absorption peak at 390 nm, which is present in the OIH spectra, proving the presence of the compound. In the case of compound 3b, a maximum absorption wavelength at 412 nm was found, and the compound peak was not clear, which may indicate that an interaction between the compound and the matrix occurred. A synergetic effect between the intrinsic emission of the matrix and the fluorescence of 3a is found on the OIH-doped matrices.

Maximum Absorption of the Global 21 cm Spectrum in the Standard Cosmological Model

The absorption feature in the global spectrum is likely the first 21 cm observable from the cosmic dawn, which provides valuable insights into the earliest history of structure formation. We run a set of high-resolution hydrodynamic simulations of early structure formation to assess the effect of nonlinear structure formation on the maximum absorption level (i.e., assuming the spin temperature coupling is saturated) of the global 21 cm spectrum in the standard cosmological framework. We ignore the star formation and feedbacks, which also tend to reduce the absorption signal, but take into account the inevitable nonlinear density fluctuations in the intergalactic medium (IGM), shock-heating, and Compton-heating, which can reduce the absorption level. We found that the combination of these reduced the maximum absorption signal by ∼15% at redshift 17, as compared with the homogeneous or linearly-fluctuating IGM. These effects have to be carefully accounted for when interpreting the observational results, especially when considering the necessity of introducing new physics.

Development of methods of identification and quantitative determination of active substances in semi-solid dosage forms with sapropel extracts

For use in veterinary medicine for the treatment of the wound process and the prevention of mastitis, the composition and technology of an emulsion-based cream, conventionally called “Saprocream”, has been developed. Clinical trial of the drug “Saprocream” proved its effectiveness and safety for use in the healing of microtraumas, erosions and cracks (wounds) of the udders of cows. The aim of the research were was the standardization of the cream under the conventional name “Saprocream” for use in veterinary medicine as a wound healing agent, the development of methods of identification and quantification and their validation. Materials and methods. Test samples of emulsion cream type o / v, containing 15 % aqueous extract of sapropel (VES), 10 % oil extract of sapropel (OES), 6 % emulsifier No. 1, 1 % cetylstearyl alcohol, preservatives – 0.01 % nisin, 0.1 % euxil K 100 and purified water up to 100 g were made by phase inversion. The methods of pharmacopoeial articles of the European Pharmacopoeia of the 10th edition, SPhU 1.0, as well as industry standards were used to develop methods for identification and quantification of active pharmaceutical ingredients (API) in the developed cream and its standardization. Results. The chromatographic profile of the acetone extract from the cream coincides with the chromatographic profile of the reference solution ((PRS) β-carotene), which indicates the presence of substances of carotenoid structure. The absorption spectrum of hexane extraction from the cream in the range from 500 nm to 750 nm has a maximum absorption at a wavelength of 670±2 nm, which coincides with the maximum absorption of hexane solution OES, indicating the presence of chlorophyll. A method for quantifying the total mass fraction of humic acids (HA) has been developed and it has been established that the total mass fraction of HA in cream samples with sapropel extracts is 0.828 %. The results of the validation of the method show that there is a linear relationship between the concentration of the total mass fraction of HA and the mass of the AES sample with a correlation coefficient of 0.9981 (³ 0.9981). The developed technique is precise, because the value of the relative confidence interval is less than the critical value for the convergence of the results: D %=1.34≤1.60 and the criterion of insignificance of systematic error d=0.51 is fulfilled. Conclusions. An emulsion-based cream under the conventional name “Saprocream” has been standardized, methods for identification and quantification of active substances have been developed and validation of the developed methods for use in veterinary medicine as a wound-healing and anti-inflammatory agent has been carried out.

Development of Absorbent Using Amylose-Graphite Composite Electrode for Removal of Heavy Metals

Amylose of Phragmites Australis captures heavy metals in a box consisting of sugar chains. However, its absorption rate is low in the period of the month scale. Therefore, the electrochemical driving force was used to promote the absorption rate in this research. Amylose was doped with TiO2 porous graphite electrode. The composted absorbent was characterized using XRD(X-ray diffraction), SEM (Scanning Electrode Microscopy), Raman spectroscopy, and electrochemical methods. The affinity and maximum absorption amount were calculated using the isotherm method. In this study, Pb2+, Cu2+, Cd2+, and Cr6+ were chosen to demonstrate because these heavy metals are significant pollutants in Japan’s surface water. It was found that the maximum absorption was Cu2+ (56.82-mg/L) > Pb2+ (55.89-mg/L) > Cr6+ (53.97-mg/L) > Cd2+ (52.83.68-mg/L) at −0.5 V vs. Ag/AgCl. This is approximately the same order as the hydration radius of heavy metals. In other words, the absorption amounts were determined by the size of heavy metal ions. Subsequently, the mixed heavy metal standard solution was tested; the maximum absorption amount was 21.46 ± 10.03 mg/L. It was inferred that the electrochemical driving force could be shown as the ion size effect in the mixed solution. Despite there being no support for this hypothesis at this time, this study succeeded in showing that the electrochemical driving force can improve the ability of the absorbent.

Influence of ultrasound on the synthesis of silver nanoparticles by galvanic replacement in sodium polyacrylate solutions

Sonogalvanic replacement and galvanic replacement synthesis of silver nanoparticles (AgNPs) by magnesium scrap in sodium polyacrylate solutions were studied. It was found that during these processes in NaPA solutions silver is practically not deposited on the magnesium surface. Sodium polyacrylate provides stabilization of AgNPs with the formation of yellow solutions with maximum absorption of ~415 nm. It is shown that sonogalvanic replacement synthesis of AgNPs occurs due to the simultaneous course of galvanic replacement by magnesium and sonoreduction of Ag (I) by radicals and reducing agents. The rate of sonogalvanic replacement synthesis of AgNPs is 20-30% higher compared to galvanic substitution by mechanical stirring.

THE DEVELOPMENT OF METHODS FOR DETERMINATION THE TOTAL OF ANTHRACENE DERIVATIVES IN RAW MATERIALS AND PREPARATIONS OF ALOE ARBORESCENS MILL.

Aloe arborescens Mill., family Asphodelaceae, is a pharmacopoeial plant, the raw material of which is used for the production of medicinal products for various therapeutic uses. The standardization of Aloe species in accordance with the requirements of the British, Japanese, European Pharmacopoeias and the United States Pharmacopoeia is carried out according to the barbaloin content by the spectrophotometric method. The methods are multistage, provide for preliminary acid hydrolysis in combination with the oxidation, liquid-liquid extraction of the formed aglycones and subsequent complexation with magnesium acetate. A mixture of isomers of aloin A and aloin B (barbaloin) and aloenin were isolated by chromatographic methods. It was determined that in all electronic spectra of the extracts and preparations from the leaves of Aloe arborescens Mill., a bathochromic shift of the long-wavelength band in the alkaline-ammonia solution is observed, which confirms the presence of anthracene derivatives. Under conditions of differential absorption, a maximum absorption is observed in the range of 412–416 nm, which indicates the advisability of using barbaloin in the analysis method, which has a maximum absorption at a wavelength of 412 nm. As a result of the study, there were developed methods for the quantitative determination of the total of anthracene derivatives in leaves and preparations of Aloe arborescens Mill. by using of the differential spectrophotometry calculated on barbaloin at an analytical wavelength of 412 nm. The content of total anthracene derivatives calculated on barbaloin was 0.60±0.03% in Aloe arborescens fresh leaves, 0.5±0.02% in freshly prepared juice, 0.135±0.006% in "Aloe juice" and 0.020±0.001% in "Aloe liquid extract", solution for subcutaneous administration, produced by ZAO "Vifitech" and OAO "Dalkhimpharm".

Simple two spectrophotometric methods for estimation of Cephalexin in pure and pharmaceutical dosage form

This study describes two extraction-free and direct spectrophotometric methods for the determination of Cephalexin in a pure and pharmaceutical dosage form. In this study, a zero-order method has exhibited maximum absorption max at 263 nm, while area under curve method has calculated in the range 260-266nm. The Linearity of both methods in the range (10- 60 nm), the limit of detection (LOD) is 0.808 for Zero-order method and 0.781 for the area under curve method. These methods are successfully applied to determination of Cephalexin in a pharmaceutical dosage form.