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Cortical hem signaling center: functions, development, and potential implications for evolution and brain disorders

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Neural Regeneration Research 2025年第4期20卷 1079-1080页

作者： victor v.Chizhikov igor Y.Iskusnykh Department of Anatomy and Neurobiology University of Tennessee Health Science CenterMemphisTNUSA

Development of the telencephalon relies upon several signaling centers-localized cellular populations that supply secreted factors to pattern the cortical *** such signaling center is the cortical hem,which arises during embryonic development at the telencephalic dorsal midline,adjacent to the choroid plexus and hippocampal primordium(Figure 1A).While the cortical hem has also been described in reptiles and birds,most of our knowledge about the developmental roles of the cortical hem is derived from the analysis in *** cortical hem produces several types of secreted molecules,including wingless-related integration site(Wnt)and bone morphogenetic(Bmp)*** cortical hem is particularly important for the development of the hippocampus,which is involved in learning and memory,and the neocortex,which is the most complex brain region that mediates multiple types of behavior and higher cognitive functions(Mangale et al.,2008;Dal-valle-Anton and Borrell,2022).

关键词： epithelium Figure center

Crystal structure prediction at finite temperatures

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npj Computational Materials 2023年第1期9卷 306-313页

作者： Ivan A.Kruglov Alexey v.yanilkin Yana Propad Arslan B.Mazitov Pavel Rachitskii Artem R.Oganov Moscow Institute of Physics and Technology 9 Institutsky laneDolgoprudny 141700Russia Dukhov Research Institute of Automatics(vNIIA) Moscow 127055Russia Emerging Technologies Research Center XPANCEODubai Investment Park FirstDubaiUnited Arab Emirates Skolkovo Institute of Science and Technology Skolkovo Innovation Center30-1 Bolshoy blvdMoscow 121205Russia.

Crystal structure prediction is a central problem of crystallography and materials science, which until mid-2000s was consideredintractable. Several methods, based on either energy landscape exploration or, more commonly, global optimization, largely solvedthis problem and enabled fully non-empirical computational materials discovery. A major shortcoming is that, to avoid expensivecalculations of the entropy, crystal structure prediction was done at zero Kelvin, reducing to the search for the global minimum ofthe enthalpy rather than the free energy. As a consequence, high-temperature phases (especially those which are not quenchableto zero temperature) could be missed. Here we develop an accurate and affordable solution, enabling crystal structure prediction atfinite temperatures. Structure relaxation and fully anharmonic free energy calculations are done by molecular dynamics with aforcefield (which can be anything from a parametric forcefield for simpler cases to a trained on-the-fly machine learning interatomicpotential), the errors of which are corrected using thermodynamic perturbation theory to yield accurate results with full ab initioaccuracy. We illustrate this method by applications to metals (probing the P–T phase diagram of Al and Fe), a refractory covalentsolid (WB), an Earth-forming silicate MgSiO_(3) (at pressures and temperatures of the Earth’s lower mantle), and ceramic oxide HfO_(2).

关键词： prediction structure Crystal

Microheterogeneity of the Koupol Deposit Fahlores as a Reflection of Changing of Physicochemical Parameters of the Ore-Forming Solution

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Journal of Earth Science 2013年第2期24卷 179-187页

作者： igor'v Kemkin Raisa A Kemkina Far East Geological Institute Far Eastern Branch of the Russian Academy of Sciences Far East Federal University

New data on a zonal structure of the Koupol deposit fahlores grains are given, and features of their chemism are shown. The fahlores chemical composition within the zones evolves from essentially arsenious （Fe-tennantite and Zn-tennantite）, through mixed fahlores （Zn-tennantitetetrahedrite arsenious and Zn-tennantite-tetrahedrite antimonous）, to essential antimonous （Ag-bearing Zn-tetrahedrite）. varying chemical composition manifested as mineralogical-geochemical zonation of the fahlores grains is caused by changes of physicochemical conditions of the ore forming process during the time.

关键词： fahlore mineralogical-geochemical zonation physicochemical condition Koupol deposit.

Comparative geochemical study of the cherty rocks of the Taukha terrane(Sikhote-Alin)and its paleogeodynamic significance

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Acta Geochimica 2020年第4期39卷 539-560页

作者： igor v.Kemkin Raisa A.Kemkina Far East Geological Institute Far Eastern Branch of Russian Academy of SciencesProspect 100-Letiya Vladivostoka159VladivostokRussia 690022 Far Eastern Federal University Soukhanova Street8VladivostokRussia 690950

The article presents the results of a comparative geochemical study of cherts and siliceous-clayey rocks composing the tectono-sedimentary complexes of various structural levels of the Taukha terrain of the Sikhote-Alin Late Jurassic-Early Cretaceous accretionary *** data obtained show that the same-aged parts of the crosssections of the cherty-terrigenous sequences of the terrane lower and middle structural levels are characterized by significantly different contents and distribution patterns of major petrogenic oxides,trace,and rare-earth elements due to their accumulation in various facies of oceanic *** set of geochemical data indicates that the formation of both tectono-sedimentary complexes was carried out differently,gradually replacing each others’facies oceanic zones,and started in the near-spreading ridge area,then in the pelagial,and completed in the continental-margin deposition *** on the time interval of the facies conditions changing for each complex(i.e.,time of transition from one facies zone to another),the speeds of a paleo-oceanic plate motion(and,correspondingly,the speeds of spreading)for individual intervals of the Jurassic were *** in the spreading speeds at various sites of a paleorift zone caused the turning of a paleocontinent margin contour and spreading ridge axis at the perpendicular position,which in turn caused change of the geodynamic mode on the eastern margin of the PaleoAsian continent at the Jurassic-Cretaceous transition.

关键词： Geochemistry Radiolarian cherts Deposition environment Paleo-Pacific plate Sikhote-Alin

Influence of Pt/Pd state on ceria-based support in CO oxidation

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Journal of Rare Earths 2023年第12期41卷 1963-1968,I0005页

作者： igor v.Zagaynov Elena Yu.Liberman Alexander v.Naumkin A.A.Baikov Institute of Metallurgy and Materials Science MoscowRussia D.I.Mendeleev University of Chemical Technology of Russia MoscowRussia A.N.Nesmeyanov Institute of Organoelement Compounds MoscowRussia

Noble metal(M:Pt,Pd,PtPd) supported on ceria system catalysts were *** oxidized and reduced forms of the active component were examined in CO *** catalysts become more active after a reduction pretreatment,which shifts the temperature of CO *** of the data obtained from characterization techniques indicates that the strong interaction of metal ions with the support prevent the reduction of the initial MO_(x)to metallic *** formation of M-ceria interfaces efficiently boosts the oxygen activation during CO oxidation,leading to the formation of chemisorbed O on M and the regeneration of the ceria lattice oxygen,thus greatly improving the catalytic performance.

关键词： Ceria Platinum Palladium CO oxidation Rare earths

Heat Transfer and Fluid Flow over a Single Disk in a Fluid Rotating as a Rigid Body

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Journal of Thermal Science 2004年第3期13卷 279-282页

作者： igor v. SHEvCHUK Matthias H. BUSCHMANN Institute of Engineering Thermophysics Ukrainian National Academy of Sciences 2a Zhelyabov St. Kiev 03057 UkraineInstitute of Fluid Mechanics Dresden University of Technology 01062 Dresden Germany

Laminar heat transfer problem is analyzed for a disk rotating with the angular speed ωin a co-rotating fluid (with the angular speed Ω). The fluid is swirled in accordance with a forced-vortex law, it rotates as a solid body at β= Ω/ω= const. Radial variation of the disk’s surface temperature follows a power law. An exact numerical solution of the problem is obtained basing on the self-similar profiles of the local temperature of fluid, its static pressure and velocity components. Numerical computations were done at the Prandtl numbers Pr = 1(?)0.71. It is shown that with increasing βboth radial and tangential components of shear stresses decrease, and to zero value at β= 1. Nusselt number is practically constant at β= 0(?) 0.3 (and even has a point of a maximum in this region); Nu decrease noticeably for larger βvalues.

关键词： rotating disk heat transfer fluid flow Nusselt number swirl.

On the possible orbital motion of Sgr A* in the smooth potential of the Milky Way

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Research in Astronomy and Astrophysics 2020年第12期20卷 383-390页

作者： igor’I.Nikiforov Angelina v.veselova St.Petersburg State University Universitetskij Prospekt 28Staryj PeterhofSt.Petersburg 198504Russia

The modern accuracy of measurements allows the residual/peculiar(Galactocentric) velocity of the supermassive black hole(SMBH) in our Galaxy, Sgr A*, on the order of several kilometers per *** integrate possible orbits of the SMBH along with the surrounding nuclear stellar cluster(NSC) for a barred model of the Galaxy using modern constraints on the components of the SMBH Galactocentric velocity. Is is shown that the range of oscillations of the SMBH + NSC in a regular Galactic field in the plane of the Galaxy allowed by these constraints strongly depends on the set of central components of the Galactic potential. If the central components are represented only by a bulge/bar, for a point estimate of the SMBH Galactocentric velocity, the oscillation amplitude does not exceed 7 pc in the case that a classical bulge is present and reaches 25 pc if there is no bulge;with SMBH velocity components within the 2σ significance level, the amplitude can reach 15 and 50 pc, respectively. However, when taking into account the nuclear stellar disk(NSD), even in the absence of a bulge, the oscillation amplitude is only 5 pc for the point estimate of the SMBH velocity, and 10 pc for the 2σ significance level. Thus, the possible oscillations of the SMBH + NSC complex from the confirmed components of the Galaxy’s potential are mostly limited by the NSD, and even taking into account the uncertainty of the mass of the latter, the oscillation amplitude can hardly exceed 13 pc = 6′.

关键词： Galaxy:center Galaxy:fundamental parameters Galaxy:kinematics and dynamics

Segments of spiral arms of the Galaxy traced by classical Cepheids:effects of age heterogeneity

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Research in Astronomy and Astrophysics 2020年第12期20卷 357-366页

作者： Angelina v.veselova igor’I.Nikiforov Department of Celestial Mechanics Saint Petersburg State UniversityUniversitetskij Prospekt 28Staryj PeterhofSaint Petersburg198504 Russia

We investigated the dependence of the parameters of the segments of spiral arms of the Galaxy on the age of classical *** catalog of Cepheids(Mel’nik et al.)was divided into two samples—relatively young(P>9d)and relatively old(Pvalue of R0=8.08^+0.2/-10.20|stat.^+0.38/-0.36|*** is shown that the displacement between the segments is not reduced to the effect of differential rotation *** interpret this displacement for objects of Perseus and Sagittarius-2 segments,we carried out a dynamic modeling of the change in the position of the segment points when moving in the smooth gravitational field of the *** the angular velocity of rotation of the spiral pattern Ωp=25.2±0.5 km s 1 kpc 1(Dambis et al.)the observed displacement between segments on young and old objects can be explained by the amplitude of spiral perturbations of the radial velocity of u=10±1.5 km s *** the constructed double system of spiral segments,it is demonstrated that the assumption of constancy of the pitch angles within each segment and the assumption that the pole of the spiral pattern is in the direction of the nominal center of the Galaxy do not contradict the data within the range of uncertainty.

关键词： Galaxy:fundamental parameters Galaxy:structure

Thermal radiation and natural convection in a large-scale enclosure heated from below:Building application

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Building Simulation 2021年第3期14卷 681-691页

作者： Stepan A.Mikhailenko igor v.Miroshnichenko Mikhail A.Sheremet Laboratory on Convective Heat and Mass Transfer Tomsk State University634050 TomskRussia Regional Scientific and Educational Mathematical Centre Tomsk State University634050 TomskRussia

A computational research of radiative-convective energy transport in large-scale enclosure with a heat-generating heater under normal room conditions has been *** heater(underfloor heating system)is located at the bottom of the *** the Boussinesq assumption,the control equations have been solved contemporaneously to receive both the velocity fields and temperature *** generate the systems of linear equations using vorticity and stream function,the finite difference technique has been *** developed convective-radiative model has been validated through a comparison with several *** influence of heater size and location,internal surfaces emissivity from 0 to 1,Ostrogradsky number for a wide range from 0 to 5 on Nusselt numbers and both stream function and temperature distributions has been *** results demonstrate that the influence of the thermal radiation on total heat transfer increases with surface emissivity of walls and heater surfaces.

关键词： indoor environment natural convection thermal radiation large-scale cabinet local heater finite difference method