Investigation of the Application of a New Method of Extraction Intensification of Pectin Substances From a Beet Pulp

The aim of research is studying a new method for intensifying extraction of pectin substances during acid extraction of pectin-containing raw materials. The description of the experimental setup and the procedure for processing the results of the investigation of the application of a new method for intensifying the beet pulp extraction are described. The results of experimental studies on the application of a new combined mixing element for intensifying the extraction of pectin-containing raw materials (beet pulp) and its effect on quantitative and qualitative output characteristics are presented. Mathematical models are constructed on the basis of regression equations of the full factorial experiment with the use of a new method of intensifying the extraction process to select input technological parameters for the extraction of pectin substances from pectin-containing raw materials. The rational operating parameters of the process of extraction of pectin substances with the use of a new combinable stirring element are determined. Such working parameters are: the process duration is 1 ... 1.1, the temperature of the working medium is 60 ... 70 ºС, and the hydromodule is 8 ... 10. The research results can be used to study other technological parameters of the extraction process of pectin substances, as well as to develop a technological line for the production of pectin products

Giga-Hertz quantized charge pumping in bottom gate defined InAs nanowire quantum dots

Semiconducting nanowires (NWs) are a versatile, highly tunable material platform at the heart of many new developments in nanoscale and quantum physics. Here, we demonstrate charge pumping, i.e., the controlled transport of individual electrons through an InAs NW quantum dot (QD) device at frequencies up to $1.3\,$GHz. The QD is induced electrostatically in the NW by a series of local bottom gates in a state of the art device geometry. A periodic modulation of a single gate is enough to obtain a dc current proportional to the frequency of the modulation. The dc bias, the modulation amplitude and the gate voltages on the local gates can be used to control the number of charges conveyed per cycle. Charge pumping in InAs NWs is relevant not only in metrology as a current standard, but also opens up the opportunity to investigate a variety of exotic states of matter, e.g. Majorana modes, by single electron spectroscopy and correlation experiments.Comment: 21 page

Assessment of protein-protein interfaces in cryo-EM derived assemblies

Structures of macromolecular assemblies derived from cryo-EM maps often contain errors that become more abundant with decreasing resolution. Despite efforts in the cryo-EM community to develop metrics for map and atomistic model validation, thus far, no specific scoring metrics have been applied systematically to assess the interface between the assembly subunits. Here, we comprehensively assessed protein–protein interfaces in macromolecular assemblies derived by cryo-EM. To this end, we developed Protein Interface-score (PI-score), a density-independent machine learning-based metric, trained using the features of protein–protein interfaces in crystal structures. We evaluated 5873 interfaces in 1053 PDB-deposited cryo-EM models (including SARS-CoV-2 complexes), as well as the models submitted to CASP13 cryo-EM targets and the EM model challenge. We further inspected the interfaces associated with low-scores and found that some of those, especially in intermediate-to-low resolution (worse than 4 Å) structures, were not captured by density-based assessment scores. A combined score incorporating PI-score and fit-to-density score showed discriminatory power, allowing our method to provide a powerful complementary assessment tool for the ever-increasing number of complexes solved by cryo-EM

MODIFICATION OF THE ORGANO-POLYMERIC ANIONITES SURFACE WITH XYLENOL ORANGE BY SORPTION

In this paper, the peculiarities of xylenol orange sorption removal with the help of organopolymeric anion exchangers AB-17-8 and Granion AWA-G1 in the static mode are studied. The state of the matrix and the surface of the organopolymeric anion exchanger granion AWA-G1 was characterized by the IR and Raman spectroscopy. It was established that at pH 5 and 9 the maximum sorption removal (90-95%) of xylenol orange by organopolymeric anion exchanger Granion AWA-G1 lasts for 60 minutes. On the basis of the obtained sorption isotherms and the calculated thermodynamic characteristics, it was concluded that the formation of the adsorption layer occurs spontaneously by a mixed mechanism. The initial process of adsorption layer formation due to chemisorption mechanism. Below, at high concentration of xylenol orange the sorption mechanism changes to the physical nature. It was shown that with changes in temperature and pH, the type of isotherms changes from L3 to H4, which indicates a high affinity of the adsorbate to the adsorbent surface. The obtained sorption isotherms are satisfactorily described by the Langmuir adsorption model. It was shown that the increase in temperature is accompanied by an increase in the amount of sorbed xylenol orange, which is due to the acceleration of the process of reorientation of sorbate molecules to the vertical. In the study of xylenol orange desorption from the Granion AWA-G1 anionite surface, it was found that distilled water and 1M solutions of sulphuric acid slightly desorb xylenol orange (Sdes ≤ 25%), in contrast, the desorption of xylenol orange with 1 M sodium hydroxide solutions reaches Sdes ~ 65%. Thus, the organopolymeric anion exchanger granion AWA-G1 modified with xylenol orange is resistant to water and acid desorption and can subsequently be used as a solid-phase reagent

MODIFICATION OF THE ORGANO-POLYMERIC ANIONITES SURFACE WITH XYLENOL ORANGE BY SORPTION

In this paper, the peculiarities of xylenol orange sorption removal with the help of organopolymeric anion exchangers AB-17-8 and Granion AWA-G1 in the static mode are studied. The state of the matrix and the surface of the organopolymeric anion exchanger granion AWA-G1 was characterized by the IR and Raman spectroscopy. It was established that at pH 5 and 9 the maximum sorption removal (90-95%) of xylenol orange by organopolymeric anion exchanger Granion AWA-G1 lasts for 60 minutes. On the basis of the obtained sorption isotherms and the calculated thermodynamic characteristics, it was concluded that the formation of the adsorption layer occurs spontaneously by a mixed mechanism. The initial process of adsorption layer formation due to chemisorption mechanism. Below, at high concentration of xylenol orange the sorption mechanism changes to the physical nature. It was shown that with changes in temperature and pH, the type of isotherms changes from L3 to H4, which indicates a high affinity of the adsorbate to the adsorbent surface. The obtained sorption isotherms are satisfactorily described by the Langmuir adsorption model. It was shown that the increase in temperature is accompanied by an increase in the amount of sorbed xylenol orange, which is due to the acceleration of the process of reorientation of sorbate molecules to the vertical. In the study of xylenol orange desorption from the Granion AWA-G1 anionite surface, it was found that distilled water and 1M solutions of sulphuric acid slightly desorb xylenol orange (Sdes ≤ 25%), in contrast, the desorption of xylenol orange with 1 M sodium hydroxide solutions reaches Sdes ~ 65%. Thus, the organopolymeric anion exchanger granion AWA-G1 modified with xylenol orange is resistant to water and acid desorption and can subsequently be used as a solid-phase reagent

Tunable kinoform x-ray beam splitter

© 2017 Optical Society of America. We demonstrate an x-ray beam splitter with high performances for multi-kilo-electron-volt photons. The device is based on diffraction on kinoform structures, which overcome the limitations of binary diffraction gratings. This beam splitter achieves a dynamical splitting ratio in the range 0–99.1% by tilting the optics and is tunable, here shown in a photon energy range of 7.2–19 keV. High diffraction efficiency of 62.6%, together with an extinction ratio of 0.6%, is demonstrated at 12.4 keV, with angular separation for the split beam of 0.5 mrad. This device can find applications in beam monitoring at synchrotrons, at x-ray free electron lasers for online diagnostics and beamline multiplexing and, possibly, as key elements for delay lines or ultrashort x-ray pulses manipulation