Adaptive Tuning of Feedback Gain in Time-Delayed Feedback Control

We demonstrate that time-delayed feedback control can be improved by adaptively tuning the feedback gain. This adaptive controller is applied to the stabilization of an unstable fixed point and an unstable periodic orbit embedded in a chaotic attractor. The adaptation algorithm is constructed using the speed-gradient method of control theory. Our computer simulations show that the adaptation algorithm can find an appropriate value of the feedback gain for single and multiple delays. Furthermore, we show that our method is robust to noise and different initial conditions.Comment: 7 pages, 6 figure

Shot noise of large charge quanta in superconductor/semiconductor/superconductor junctions

We have found experimentally that the noise of ballistic electron transport in a superconductor/semiconductor/superconductor junction is enhanced relative to the value given by the general relation, S_V=2eIR^2coth(eV/2kT), for two voltage regions in which this expression reduces to its thermal and shot noise limits. The noise enhancement is explained by the presence of large charge quanta, with effective charge q*=(1+2Delta/eV)e, that generate a noise spectrum S_V=2q*IR^2, as predicted in Phys. Rev. Lett. 76, 3814 (1996). These charge quanta result from multiple Andreev reflections at each junction interface, which are also responsible for the subharmonic gap structure observed in the voltage dependence of the junction's conductance.Comment: 5 pages, 5 figures, submitted to Physical Review B as a Rapid Communication. v2 author name in reference corrected. v3 added references. v4 clarifications in the text and reference added thanks to C. Urbin

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

Medicaments administration into the subtenon eye space in treatment of anterior ischemic neuropathy.

In spite of treatment provided inanterior ischemic neuropathy, a prognosis for visual functions is poor and depends on severity of affection ofvascular system of the body. We have studied the exposure to cortexin and diprospan in subtenon administration on the eye hemodynamics in 18 patients experiencing anterior ischemic neuropathy(18 eyes) who have been treated operatively (administration of cortexin and diprospan into the subtenon space of the affected eye) against the background of complex conservative prevention. The control group was constituted of 16 patients (16 eyes) who have not been treated operatively. As a result of provided treatment the patients of the basic group showed increase of vision acuity, field of view limits and eye ground state.

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