Electronic structure and magnetic properties of the spin-1/2 Heisenberg system CuSe2O5

A microscopic magnetic model for the spin-1/2 Heisenberg chain compound CuSe2O5 is developed based on the results of a joint experimental and theoretical study. Magnetic susceptibility and specific heat data give evidence for quasi-1D magnetism with leading antiferromagnetic (AFM) couplings and an AFM ordering temperature of 17 K. For microscopic insight, full-potential DFT calculations within the local density approximation (LDA) were performed. Using the resulting band structure, a consistent set of transfer integrals for an effective one-band tight-binding model was obtained. Electronic correlations were treated on a mean-field level starting from LDA (LSDA+U method) and on a model level (Hubbard model). In excellent agreement of experiment and theory, we find that only two couplings in CuSe2O5 are relevant: the nearest-neighbour intra-chain interaction of 165 K and a non-frustrated inter-chain coupling of 20 K. From a comparison with structurally related systems (Sr2Cu(PO4)2, Bi2CuO4), general implications for a magnetic ordering in presence of inter-chain frustration are made.Comment: 20 pages, 8 figures, 3 table

Conductive Atomic Force Microscopy study of local resistive switching by a complex signal in the yttria stabilized zirconia films

This work was supported by RFBR (18-42-520059р_а)

Studying the pharmacokinetics of biotechnological medicinal products on the example of monoclonal antibodies

Therapeutic monoclonal antibodies (mAbs), which are developed to treat many pathologies, including cancer, autoimmune and infectious diseases, are one of the fastest growing classes of medicinal products. Given the large number of mAbs in the pipeline and continued interest from pharmaceutical companies, the mAb market is expected to continue to grow in the coming years. To maximise both the therapeutic benefit and the safety of medicinal products in this class, it is essential that their pharmacological properties be carefully characterised and understood.The aim of the study was to analyse literature data on approaches to studying the pharmacokinetics of mAbs. This review presents data on the main physicochemical and pharmacological properties of mAbs and compares them with small molecules. The article describes the influence of various factors on mAb pharmacokinetics.For example, such factors include the method of administration, hydrophilicity, and charge of the mAb, individual characteristics of the patient (body weight, plasma albumin levels, genetic characteristics, etc.), and concurrent administration of other medicinal products. The authors evaluated the role of intra- and inter-individual variability of pharmacokinetic parameters. The rapid development of this group of medicinal products and the emergence of new promising molecules are indicative of the need to study the pharmacokinetics and pharmacodynamics of mAbs in detail and to maximise both the therapeutic benefit and the safety of the medicinal products in this class

Методика регистрации угловых диаграмм отражения и рассеяния света прецизионных оптических поверхностей

Описано методику реєстрації кутових діаграм відбивання і розсіяння світла і показано, що за індикатрисами розсіяння при оптимальному напрямку спостереження можна оцінити шорсткість оптичних поверхонь за шириною піка, що спостерігається на фоні незмінного п’єдесталу.The technique of registration of angular diagram’s of reflexion and dispersion of light is described and is shown, that on in indicatrix dispersion at an optimum direction of supervision it is possible to estimate a roughness of optical surfaces on width of peak which is observed against an invariable pedestal.Описана методика регистрации угловых диаграмм отражения и рассеяния света и показано, что по индикатрисам рассеяния при оптимальном направлении наблюдения можно оценить шероховатость оптических поверхностей по ширине пика, который наблюдается на фоне неизменного пьедестала

A Hydrophobic Gate in an Ion Channel: The Closed State of the Nicotinic Acetylcholine Receptor

The nicotinic acetylcholine receptor (nAChR) is the prototypic member of the `Cys-loop' superfamily of ligand-gated ion channels which mediate synaptic neurotransmission, and whose other members include receptors for glycine, gamma-aminobutyric acid, and serotonin. Cryo-electron microscopy has yielded a three dimensional structure of the nAChR in its closed state. However, the exact nature and location of the channel gate remains uncertain. Although the transmembrane pore is constricted close to its center, it is not completely occluded. Rather, the pore has a central hydrophobic zone of radius about 3 A. Model calculations suggest that such a constriction may form a hydrophobic gate, preventing movement of ions through a channel. We present a detailed and quantitative simulation study of the hydrophobic gating model of the nicotinic receptor, in order to fully evaluate this hypothesis. We demonstrate that the hydrophobic constriction of the nAChR pore indeed forms a closed gate. Potential of mean force (PMF) calculations reveal that the constriction presents a barrier of height ca. 10 kT to the permeation of sodium ions, placing an upper bound on the closed channel conductance of 0.3 pS. Thus, a 3 A radius hydrophobic pore can form a functional barrier to the permeation of a 1 A radius Na+ ion. Using a united atom force field for the protein instead of an all atom one retains the qualitative features but results in differing conductances, showing that the PMF is sensitive to the detailed molecular interactions.Comment: Accepted by Physical Biology; includes a supplement and a supplementary mpeg movie can be found at http://sbcb.bioch.ox.ac.uk/oliver/download/Movies/watergate.mp

The generation of the electrical oscillations in a contact of an AFM probe with an individual Au nanoparticle in a SiO2/Si film

Сообщается о наблюдении электрических колебаний в колебательном контуре, включѐнном в цепь контакта АСМ зонда к туннельно-прозрачной (толщиной ~5 нм) плѐнке SiO2/Si с наночастицами (НЧ) u. Эффект связан с резонансным туннелированием через размерно-квантованные состояния в малых (~1 нм) НЧ u.The electrical oscillations in an oscillating loop connected to an AFM probe contact to a tunnel-transparent (~5 nm thick) SiO2/Si film with Au nanoparticles (NPs) have been observed. The effect was attributed to the resonant tunneling via the quantum confined states in small (~1 nm) Au NPs.Работа выполнена при поддержке Минобрнауки РФ (16.7864.2017/БЧ)

Исследование фармакокинетики биотехнологических препаратов на примере моноклональных антител

Therapeutic monoclonal antibodies (mAbs), which are developed to treat many pathologies, including cancer, autoimmune and infectious diseases, are one of the fastest growing classes of medicinal products. Given the large number of mAbs in the pipeline and continued interest from pharmaceutical companies, the mAb market is expected to continue to grow in the coming years. To maximise both the therapeutic benefit and the safety of medicinal products in this class, it is essential that their pharmacological properties be carefully characterised and understood.The aim of the study was to analyse literature data on approaches to studying the pharmacokinetics of mAbs. This review presents data on the main physicochemical and pharmacological properties of mAbs and compares them with small molecules. The article describes the influence of various factors on mAb pharmacokinetics.For example, such factors include the method of administration, hydrophilicity, and charge of the mAb, individual characteristics of the patient (body weight, plasma albumin levels, genetic characteristics, etc.), and concurrent administration of other medicinal products. The authors evaluated the role of intra- and inter-individual variability of pharmacokinetic parameters. The rapid development of this group of medicinal products and the emergence of new promising molecules are indicative of the need to study the pharmacokinetics and pharmacodynamics of mAbs in detail and to maximise both the therapeutic benefit and the safety of the medicinal products in this class.Терапевтические моноклональные антитела (МкАт) являются одним из самых быстроразвивающихся классов лекарственных средств, которые разрабатываются для лечения многих патологий, включая рак, аутоиммунные и инфекционные заболевания. Учитывая большое количество находящихся в настоящее время в разработке МкАт и сохраняющийся интерес со стороны фармацевтических компаний, ожидается, что рынок МкАт будет продолжать расти и в последующие годы. Для максимизации как терапевтической пользы, так и безопасности препаратов этого класса крайне важно, чтобы их фармакологические свойства были тщательно охарактеризованы.Цель работы — анализ литературных данных о подходах в изучении фармакокинетических параметров моноклональных антител.Представлены данные об основных физико-химических и фармакологических свойствах МкАт. Проведен сравнительный анализ характеристик МкАт и низкомолекулярных лекарственных веществ. Показано влияние на фармакокинетические параметры МкАт различных факторов, таких как способ введения, гидрофильность и заряд МкАт, индивидуальные особенности пациентов (масса тела, уровень альбумина в плазме крови, генетические особенности и др.), совместное применение с другими лекарственными средствами. Оценена роль межиндивидуальной и внутрииндивидуальной вариабельности фармакокинетических параметров МкАт. Сделан вывод о том, что в условиях стремительных темпов разработки препаратов данной группы и появления новых перспективных молекул особо важное значение приобретает необходимость подробного изучения и оптимизации фармакокинетических и фармакодинамических свойств для повышения как терапевтической пользы, так и безопасности препаратов класса МкАт