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Recent studies have revealed critical roles for the local environments surrounding metallocofactors, such as the newly identified CuD site in particulate methane monooxygenases (pMMOs) and the second sphere aromatic residues in lytic polysaccharide monooxygenases (LPMOs), implicated in the protection against oxidative damage. However, these features are subjects of continued debate. Our work utilizes biotin-streptavidin (Sav) technology to develop artificial metalloproteins (ArMs) that mimic the active sites of natural copper metalloenzymes. By engineering ArMs with aromatic residues within their secondary coordination spheres, we systematically investigate the influence of these residues on Cu reactivity and oxidant activation. We demonstrate that the placement and orientation of tyrosine relative to the Cu cofactor critically affect the oxidation outcomes upon exposure to hydrogen peroxide. A key finding is the interplay between the coordination of an active site asparagine and the incorporation of aromatic residues proximal to the artificial Cu cofactor, which are the only variants where oxidation of an engineered residues is observed. These findings underscore the importance of the secondary coordination sphere in modulating Cu center reactivity, suggest a role for amide coordination in C-H bond activation by pMMOs, and potential inactivation pathways in natural copper enzymes like LPMOs.

Manganese hydroxido (Mn-OH) complexes supported by a tripodal N,N,N″-[nitrilotris(ethane-2,1-diyl)]tris(P,P-diphenylphosphinic amido) ([poat]3-) ligand have been synthesized and characterized by spectroscopic techniques including UV-vis and electron paramagnetic resonance (EPR) spectroscopies. X-ray diffraction (XRD) methods were used to confirm the solid-state molecular structures of {Na2[MnIIpoat(OH)]}2 and {Na[MnIIIpoat(OH)]}2 as clusters that are linked by the electrostatic interactions between the sodium counterions and the oxygen atom of the ligated hydroxido unit and the phosphinic (P=O) amide groups of [poat]3-. Both clusters feature two independent monoanionic fragments in which each contains a trigonal bipyramidal Mn center that is comprised of three equatorial deprotonated amide nitrogen atoms, an apical tertiary amine, and an axial hydroxido ligand. XRD analyses of {Na[MnIIIpoat(OH)]}2 also showed an intramolecular hydrogen bonding interaction between the MnIII-OH unit and P=O group of [poat]3-. Crystalline {Na[MnIIIpoat(OH)]}2 remains as clusters with Na+---O interactions in solution and is unreactive toward external substrates. However, conductivity studies indicated that [MnIIIpoat(OH)]- generated in situ is monomeric and reactivity studies found that it is capable of cleaving C-H bonds, illustrating the importance of solution-phase speciation and its direct effect on chemical reactivity. Synopsis: Manganese-hydroxido complexes were synthesized to study the influence of H-bonds in the secondary coordination sphere and their effects on the oxidative cleavage of substrates containing C-H bonds.

Metalloproteins with dinuclear cores are known to bind and activate dioxygen, with a subclass of these proteins having active sites containing FeMn cofactors and activities ranging from long-range proton-coupled electron transfer (PCET) to post-translational peptide modification. While mechanistic studies propose that these metallocofactors access FeIIIMnIV intermediates, there is a dearth of related synthetic analogs. Herein, the first well-characterized synthetic FeIII-(μ-O)-MnIV complex is reported; this complex shows similar spectroscopic features as the catalytically competent FeIIIMnIV intermediate X found in Class Ic ribonucleotide reductase and demonstrates PCET function towards phenolic substrates. This complex is prepared from the oxidation of the isolable FeIII-(μ-O)-MnIII species, whose stepwise assembly is facilitated by a tripodal ligand containing phosphinic amido groups. Structural and spectroscopic studies found proton movement involving the FeIIIMnIII core, whereby the initial bridging hydroxido ligand is converted to an oxido ligand with concomitant protonation of one phosphinic amido group. This series of FeMn complexes allowed us to address factors that may dictate the preference of an active site for a heterobimetallic cofactor over one that is homobimetallic: comparisons of the redox properties of our FeMn complexes with those of the di-Fe analogs suggested that the relative thermodynamic ease of accessing an FeIIIMnIV core can play an important role in determining the metal ion composition when the key catalytic steps do not require an overly potent oxidant. Moreover, these complexes allowed us to demonstrate the effect of the hyperfine interaction from non-Fe nuclei on 57Fe Mössbauer spectra which is relevant to MnFe intermediates in proteins.

Background. Analysis of studies devoted to the activities of technology parks reveals a trend of increasing their importance for the formation of students' general professional competencies in the infrastructure of pedagogical universities. Currently, pedagogical universities have basic conditions that allow creating a quasi-professional environment consistent with the technologically rich environment of a modern school. At the same time, a number of socio-cultural factors predetermine the need to prepare students to solve increasingly complex pedagogical problems in the context of a changing educational environment and expanding interactions. Purpose - development of ways to improve the basic conditions existing in a pedagogical university in order to create a quasi-professional, technologically rich educational environment taking into account modern influences. Materials and methods. The local pedagogical experience of the Herzen State Pedagogical University departments on the use of technopark resources in the professional training of students of different profiles was studied. The study involved 162 students and 22 scientific and pedagogical staff. The following research methods were used: theoretical analysis, analysis of local pedagogical experience, included pedagogical observation, survey. Results. The components of quasi-professional environment are identified and the basic conditions for its creation in a teacher training university by filling the components according to the characteristics of technologically rich educational environment of a modern school are deduced. The problems of organizational, methodical, motivational and semantic character, which hinder the creation of quasi-professional environment in the pedagogical university, are revealed. The solution to change the conditions for the creation of such a method by means of its level structuring; educational procedural tasks with the use of technopark resources; development of attitudes of the general cultural and universal plan, determining the features of interaction between the subjects of the educational process in a quasi-professional environment is proposed. Financing. The research is carried out at the expense of an internal grant from the A. I. Herzen State Pedagogical University (Project No. 31).

The work presents the study results of the stress-strain state of the soil, as a continuous medium filled with abrasive particles under the action of the working bodies of soil tillage and earthmoving machines. One of the main properties of the soil, which determines the specifics of the force interaction of the working surfaces of the working bodies of soil tillage and earthmoving machines with the technological environment, is taken into account, namely the tendency of the contact layer of the treated layer to compaction. The relationship between stress in the soil and the wear of the working bodies of soil tillage and earthmoving machines has been established experimentally. A theoretical analysis is presented for the stress-strain state of the local region of the strengthened surface layer that is used in the working bodies of soil tillage and earthmoving machines, in which the filler, inclusion or strengthening phase is placed. An analysis of the contact characteristics of the stress-strain state and their changes during friction and wear was carried out based on the formulation and solution of the contact interaction problems of abrasive soil particles with the inhomogeneities of the composite coatings components based on ultra-high molecular weight polyethylene with fillers during strengthening of the working bodies of soil tillage and earthmoving machines. Computer modeling was performed to study the nature of stress distribution in the reinforced surface layer of the working bodies of soil tillage and earthmoving machines in the area of the contact zone in stationary and dynamic conditions. The contact problem is formulated, the boundary conditions and the solution in the form of components of the stress field are given. The characteristics of the filler, their content in the composite material and coating are taken into account, the relationship between the stress-strain state and wear is established.

Objective: to evaluate the possible influence of different graft perfusion preparation variations on the incidence of biliary and vascular complications of orthotopic liver transplantation (OLT).Materials and methods. Data on 287 full-size liver transplants from donors with brain death and beating heart were processed. There were 262 and 25 primary and repeat OLTs, respectively. Before completion of portal anastomosis formation and inclusion into systemic blood flow, the graft was perfused with hypo- (group 2) and isotonic (group 4) saline in order to minimize hemodynamic disorders.Results. There was a statistically significant difference between groups 2 and 4 in the development of late (p = 0.04) and cumulative biliary complications (p = 0.01). The presence of these complications and the perfusion type were found to be associated (Fisher’s exact test = 0.02). There were no differences in incidence of thrombosis in the studied groups.Conclusion. The conducted analysis suggests that it is inexpedient to use hypothermic solutions when preparing a liver transplant for perfusion before introducing it into systemic circulation.

Fe K-edge X-ray absorption spectroscopy (XAS) has long been used for the study of high-valent iron intermediates in biological and artificial catalysts. 4p-mixing into the 3d orbitals complicates the pre-edge analysis but when correctly understood via 1s2p resonant inelastic X-ray scattering and Fe L-edge XAS, it enables deeper insight into the geometric structure and correlates with the electronic structure and reactivity. This study shows that in addition to the 4p-mixing into the 3dz2 orbital due to the short iron-oxo bond, the loss of inversion in the equatorial plane leads to 4p mixing into the 3dx2-y2,xy, providing structural insight and allowing the distinction of 6- vs 5-coordinate active sites as shown through application to the Fe(IV)═O intermediate of taurine dioxygenase. Combined with O K-edge XAS, this study gives an unprecedented experimental insight into the electronic structure of Fe(IV)═O active sites and their selectivity for reactivity enabled by the π-pathway involving the 3dxz/yz orbitals. Finally, the large effect of spin polarization is experimentally assigned in the pre-edge (i.e., the α/β splitting) and found to be better modeled by multiplet simulations rather than by commonly used time-dependent density functional theory.

The development of (bio)catalysts capable of selectively activating strong C-H bonds is a continuing challenge in modern chemistry. In both metalloenzymes and synthetic systems capable of activating C-H bonds, transition metal-oxido intermediates serve as the active species for reactivity whose thermodynamic properties influence the bond strengths they are capable of activating. In this Frontier article, we present current ideas of how the basicity of transition metal-oxidos impacts their reactivity with C-H bonds and present new opportunities within this field. We highlight recent insights into the role basicity plays in the activation process and its influence on mechanism, as well as the important role that secondary coordination sphere effects, such as hydrogen bonds, in tuning the basicity of the metal-oxido species is discussed.

XIX век знаменовался значительными изменениями в социально-экономическом и культурном развитии России. Он также характеризовался изменением положения русской женщины, особенно в городах. Это в первую очередь касалось представительниц экономически активных сословий, прежде всего купчих. История женского предпринимательства в столичных городах и ряде центральных губерний империи получила освещение, судьбы женщин-предпринимателей на Урале пока не привлекли внимание историков. Небольшой размер этой социальной группы ограничивает возможности демографического анализа, поэтому данное исследование сфокусировано на информационном потенциале демографических источников для реконструкции жизненных траекторий купеческих вдов – «матриархов», возглавивших семьи и бизнес. Основой источниковой базы работы являются данные ревизий и переписей, в том числе ревизских сказок 1858 г., первичные материалы которых были транскрибированы в электронный ресурс «Население Урала (конец XIX – начало XX в.)». В результате проведенного анализа было установлено, что предписания закона и экономическое благополучие в условиях города создавали почву для изменения демографического поведения: большинство купеческих семей состояли из родителей и детей, и их средний размер не превышал 4,4 чел. Таким образом, нуклеарность была характерна не только для столичного купечества, но и для бизнес-семей в провинциальных городах. Средний возраст вступления в брак для девушек из купеческих семей составлял 20 лет. Мужья были старше своих избранниц в среднем на шесть лет, что увеличивало вероятность раннего вдовства. Из достигших 40 лет каждая четвертая купчиха уже была вдовой, а в возрастной группе 40–49 лет – каждая вторая. Нами были прослежены жизненные траектории тех из них, кто не вышли замуж повторно и возглавили семью и бизнес. Доля купеческих семей Екатеринбурга, возглавлявшихся женщинами в 1858 г., составляла 16 %, и в них проживало 11 % всего купеческого населения города. Некоторые купчихи приобщились к бизнесу, еще будучи замужем, другие за неимением взрослых сыновей взяли на себя ответственность после смерти супругов. Были ситуации, при которых вдовствующие купчихи продолжали возглавлять большие семьи, включавшие и женатых сыновей. Это могло быть связано с финансовыми обстоятельствами, внутрисемейными договоренностями и личностными характеристиками властных матерей. Был также выявлен случай, когда вдовы приняли решение жить вместе и заниматься бизнесом. Результаты исследования показывают многих из представительниц купеческого сословия деятельными, успешными и стремившимися к лидерству.

Non-heme Fe monooxygenases activate C-H bonds using intermediates with high-spin FeIV-oxido centers. To mimic these sites, a new tripodal ligand [pop]3- was prepared that contains three phosphoryl amido groups that are capable of stabilizing metal centers in high oxidation states. The ligand was used to generate [FeIVpop(O)]-, a new FeIV-oxido complex with an S = 2 spin ground state. Spectroscopic measurements, which included low-temperature absorption and electron paramagnetic resonance spectroscopy, supported the assignment of a high-spin FeIV center. The complex showed reactivity with benzyl alcohol as the external substrate but not with related compounds (e.g., ethyl benzene and benzyl methyl ether), suggesting the possibility that hydrogen bonding interaction(s) between the substrate and [FeIVpop(O)]- was necessary for reactivity. These results exemplify the potential role of the secondary coordination sphere in metal-mediated processes.

Background. In the complex treatment of premature infants, nutrition plays an important role, the adequacy of which largely determines their growth and development.Objective. Assessment of anthropometric parameters and body composition of children with very low and extremely low body weight at birth and at 38-40 weeks of postconceptional age.Materials and methods. We conducted a cohort ambispective randomized study. It included 70 premature babies (28 girls and 42 boys), born with a body weight of less than 1000 g (group 1, n = 40) and from 1000 to 1500 g (group 2, n = 30). Anthropometric data at birth and at the time of the study were assessed using international growth standards INTERGROWTH–21st. The amount and ratio of fat and lean body mass were determined using air plethysmography.Results. When assessing the nutritional status of premature infants of both groups at term (38-40 weeks of postconceptual age), a significant decrease in standardized z-scores was found – weight, body length and head circumference for age in group 1, as well as weight and head circumference by age in the 2nd group, more pronounced in the 1st group. Malnutrition (z-score of body weight for age less than 1 SD) was detected in 77.5% of children in group 1 and 23.3% in group 2. Analysis of body composition indicators did not reveal significant differences in the percentage of fat and lean body mass in children of groups 1 and 2, but lean body mass was 440 g less in children with extremely low birth weight. In group 1, statistically significant direct correlations were established between the z-score of body weight and lean body mass, expressed both as a percentage and in kg, as well as a significant inverse correlation with body fat mass as a percentage.Conclusion. The formation of postnatal growth retardation in a significant proportion of children born weighing less than 1500 g dictates the need for careful dynamic monitoring of their nutritional status for timely correction.

Artificial metalloproteins (ArMs) have recently gained significant interest due to their potential to address issues in a broad scope of applications, including biocatalysis, biotechnology, protein assembly, and model chemistry. ArMs are assembled by the incorporation of a non-native metallocofactor into a protein scaffold. This can be achieved by a number of methods that apply tools of chemical biology, computational de novo design, and synthetic chemistry. In this Perspective, we highlight select systems in the hope of demonstrating the breadth of ArM design strategies and applications and emphasize how these systems address problems that are otherwise difficult to do so with strictly biochemical or synthetic approaches.

We have examined the dynamics of the longitudinal magnetic field of active region NOAA 12673, using data from the Solar Dynamics Observatory (SDO). During the passage of the active region (AR) across the solar disk, its spots and background fields showed complex motion trajectories, and numerous small-scale short-lived local polarity inversion lines (LPILs) were formed when new magnetic fluxes appeared in the AR and came closer to fields of opposite polarity. The length of LPILs was less than 15.000 km (~20 arcsec); their lifetime was several hours. Study of the flare activity of NOAA 12673 has shown that low-power flares (optical class S, area ˂2 sq. degrees) generally occur near LPILs. Before small flares and the September 06, 2017 large flare (optical importance 3B, X-ray class X9.3), in limited sites of local and main polarity inversion lines there were shear stresses and an increase in the magnetic field gradient: in the region of low-power flares, to 1.3–1.5 G/km; in the region of the large flare, 3–3.5 G/km. The results obtained suggest that the longitudinal magnetic field behaves similarly before both small and large flares.

Metalloproteins with active sites containing di-Fe cores exhibit diverse chemical reactivity that is linked to the precise transfer of protons and electrons which directly involve the di-Fe units. The redox conversions are commonly corroborated by spectroscopic methods, but the associated structural changes are often difficult to assess, particularly those related to proton movements. This report describes the development of di-Fe complexes in which the movements of protons and electrons are pinpointed during the stepwise oxidation of a di-FeII species to one with an FeIIIFeIV core. Complex formation was promoted using the phosphinic amido tripodal ligand [poat]3- (N,N',N″-[nitrilotris(ethane-2,1-diyl)]tris(P,P-diphenylphosphinic amido)) that provided dynamic coordination spheres that assisted in regulating both electron and proton transfer processes. Oxidation of an [FeII-(μ-OH)-FeIII] complex led to the corresponding di-FeIII species containing a hydroxido bridge that was not stable at room temperature and converted to a species containing an oxido bridging ligand and protonation of one phosphinic amido group to form [Hpoat]2-. Deprotonation led to a new species with an [FeIII-(μ-O)-FeIII] core that could be further oxidized to its FeIIIFeIV analogue. Reactions with phenols suggest homolytic cleavage of the O-H bond to give products that are consistent with the initial formation of a phenoxyl radical─spectroscopic studies indicated that the electron is transferred to the FeIV center, and the proton is initially transferred to the more sterically hindered oxido ligand but then relocates to [poat]3-. These findings offer new mechanistic insights related to the stability of and the reactions performed by di-Fe enzymes.