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Background. Liver transplantation remains a priority treatment option for hepatocellular carcinoma in the presence of liver cirrhosis; yet precise outcome prediction post-operation continues to be a complex challenge. Existing prognostic model often overlook patient age and donor type. Enhanced models that incorporate these parameters can improve prediction accuracy and treatment efficacy, which is critically important in the dynamically evolving field of transplantation.Objective. The aim of this study is to develop a prognostic model for liver transplantation outcomes in patients with hepatocellular carcinoma and liver cirrhosis.Material and methods. This retrospective study included 69 patients with hepatocellular carcinoma on the background of liver cirrhosis who underwent liver transplantation between May 2010 and December 2022. Of these, 42 patients (61%) received organs from living donors, and 27 (39%) from deceased donors. The study involved analysis of alpha-fetoprotein levels in blood, as well as assessment of radiological (maximum tumor nodule size, number of nodules) and histological parameters (maximum tumor nodule size, number of nodules, presence of vascular invasion). Cox regression model was used to predict recurrence-free survival, and the results for five-year recurrence-free survival, recipient age, and donor type were reused in the Cox model to predict overall survival.Results. Four models for predicting recurrence-free survival and overall survival based on histological and radiological data were developed, demonstrating high prognostic value with C-indexes on training/test data of 0.76/1; 0.73/1; 0.78/0.8; 0.6/0.8 respectively. All models showed recurrence-free survival prediction accuracy comparable to the Milan criteria. The model outcomes are available as a calculator on the website https://nadit.ru/calculate_HCC.Conclusion. The developed prognostic models are vital tools for personalized outcome prediction after liver transplantation for hepatocellular carcinoma. To enhance the accuracy of these models, further amalgamation and validation of data from various medical centers, as well as open scientific collaboration, are necessary.

Abstract The terrestrial bow shock is the boundary where supersonic solar wind slows down abruptly near the magnetopause. The shock front geometry could be modulated by surface waves to form rippled structures, which impact the acceleration process of the solar wind particles. However, the rippled structures are hard to be identified unambiguously due to the similar signatures in single‐spacecraft observations between rippled shocks and reforming shocks. Here, we utilize the four‐spacecraft observations from the MMS mission to investigate an event of quasi‐perpendicular bow shock crossing. The periodic oscillations of shock normal directions and normal velocities support the scenario of surface wave propagation in the tangential direction. We also reconstruct the shock profile along the normal direction, and its monotonic shape further excludes the occurrence of shock reformation. These ripples are found to modulate the reflected ions and whistler wave packets, which adds to the complexity of the bow shock plasma environments.

Abstract Whistler mode chorus waves are one of the most intense and important electromagnetic emissions in the Earth's radiation belt, where these waves are responsible for electron acceleration to relativistic energies and for energetic electron precipitation into the Earth's atmosphere. This study reports a unique multi‐spacecraft observation event that allowed for the first time to verify theoretical models of chorus wave generation. The growth rates derived from the multi‐spacecraft observations of chorus waves Cluster WBD electric field waveforms collected during the crossing of the equatorial source region were compared to the theoretical linear and nonlinear growth rates calculated using simultaneous PEACE electron measurements. We have revealed that the growth rate estimated from wave measurements is substantially higher than the estimated linear growth rate but is quite close to the estimated nonlinear growth rate. A notable wave amplification is found up to 5 degrees of magnetic latitude and higher.

Magneto-optical gyrotropic Faraday and Kerr effects are studied in the BiY2Fe5O12 films with thicknesses ranging from 16 to 55 nm, in the wavelength range of 295 nm < λ < 830 nm (4.2–1.5 eV), and under magnetic fields of up to 1.2 T. It is shown that films produced by ac magnetron sputtering on the single-crystalline diamagnetic yttrium aluminum garnet substrates Y3Al5O12 (001) exhibit high structural and magneto-optical quality. The Verdet constant for diamagnetic Y3Al5O12 is determined, and the magnitude of the Kerr effect is estimated for the polished substrate. It is shown experimentally that for a substrate with diffusely reflective backside, the Kerr effect is about zero, except in the high-energy region. For all BiY2Fe5O12 films investigated, in the saturating magnetic fields of approximately 0.16–0.2 T, the value of specific Faraday rotation reaches 20 deg/μm (200 000 deg/cm), while the value of the Kerr effect reaches approximately 20 min (5.8 mrad). The critical thickness of the film–substrate interface was estimated, highlighting variations in the Kerr effect spectra associated with a decrease in the Bi content in thin films with the thicknesses of below 27 nm. [ABSTRACT FROM AUTHOR]

Abstract Night‐side chorus waves are often observed during plasma sheet injections, typically confined around the equator and thus potentially responsible for precipitation of ≲100 keV electrons. However, recent low‐altitude observations have revealed the critical role of chorus waves in scattering relativistic electrons on the night‐side. This study presents a night‐side relativistic electron precipitation event induced by chorus waves at the strong diffusion regime, as observed by the ELFIN CubeSats. Through event‐based modeling of wave propagation under ducted or unducted regimes, we show that a density duct is essential for guiding chorus waves to high latitudes with minimal damping, thus enabling the strong night‐side relativistic electron precipitation. These findings underline both the existence and the important role of density ducts in facilitating night‐side relativistic electron precipitation.

Abstract Energetic electron precipitation (EEP) during substorms significantly affects ionospheric chemistry and lower‐ionosphere (

Abstract Electromagnetic ion cyclotron (EMIC) waves are a key plasma mode affecting radiation belt dynamics. These waves are important for relativistic electron losses through scattering and precipitation into Earth's ionosphere. Although theoretical models of such resonant scattering predict a low‐energy cut‐off of ∼1 MeV for precipitating electrons, observations from low‐altitude spacecraft often show simultaneous relativistic and sub‐relativistic electron precipitation associated with EMIC waves. Recently, nonresonant electron scattering by EMIC waves has been proposed as a possible solution to the above discrepancy. We employ this model and a large database of EMIC waves to develop a universal treatment of electron interactions with EMIC waves, including nonresonant effects. We use the Green's function approach to generalize EMIC diffusion rates foregoing the need to modify existing codes or recompute empirical wave databases. Comparison with observations from the electron losses and fields investigation mission demonstrates the efficacy of the proposed method for explaining sub‐relativistic electron losses by EMIC waves.

The current regulation provides for the possibility of creating special (free) zones and equivalent territories (hereinafter — SEZ) in the Arctic (territories of advanced development and the Arctic zone of the Russian Federation). Within the framework of SEZs, the customs procedure of a free customs zone (hereinafter — FCZ) can be applied, which provides opportunities to conduct economic activities with foreign goods without paying customs duties. The purpose of the study is to investigate the peculiarities of applying the customs procedure of a free customs zone in the Arctic. The following research methods were used in the preparation of the article: economic, analytical methods, method of comparison and generalization. This simplification can be demanded by Russian organizations — residents (participants) of the territories of advanced development and the Arctic zone of the Russian Federation. The proposed article is devoted to the consideration of the mechanisms of the above-mentioned simplifications provided for the residents of the “Arctic” SEZ. At the same time, the application of the customs procedure of FCZ in the SEZ territories is an important tool of the state economic policy, designed to ensure the creation of comfortable conditions for taxation of foreign goods. Issues related to the status of goods manufactured in SEZs using foreign goods that are placed under the FCZ customs procedure are largely related to Russia’s international obligations underlying the current regulation. In practice, the set of legally established simplifications analyzed in the article creates conditions for more effective activity of SEZ residents.

The chemical composition of 29 copper and bronze artifacts from the sites of the Petrovka and Alakul Cultures located between the Tobol and Ishim Rivers (the burial grounds of Bekteniz and Dzhangildy 5, and the sites of Novonikolskoye 1 and Semiozernoye 2; Northern Kazakhstan) were analysed using mass spectrometry with inductively coupled plasma and laser ablation. The sites are 14C dated to the interval between the 19th–17th centuries BC. In the examined sample, the leading metallurgical group with a slight prevalence in both Petrovka and Alakul metals was “pure” copper; the second part of the metal was represented by tin bronzes — low-alloyed (up to 8 wt.% Sn) in the Petrovka, and high-alloyed (Sn up to 21 wt.%) in the Alakul Culture. The statistical analysis of the main components of trace elements in the metal demonstrated a division into six main geochemical groups. Among these, tin bronzes with an uninterpretable copper component (10 specimens), “pure” copper of Ural origin with Fe-Co-Ni-As-Zn correlations (9 specimens), and “pure” copper with polymetallic Sn-Pb-As-Ag-Se specialization (10 copies), corresponding to the ores of copper deposits of the Kokshetau anticlinorium, can be identified. An overview of the tectonic structures of Northern Kazakhstan shows the nearby presence of several porphyry copper and skarn deposits with ancient mines (Imantau, Baksinskoye, Akkan-Burlukskoye, etc.), which likely served as sources of copper ore. Closely associated with these are Greisen and quartz-veingreisen tin deposits, but there is no reliable information about their use in ancient times. According to the composition of tin alloys in the analysed metal, two main types can be distinguished: tin (without correlation with other impurity elements) when using pure cassiterite, and tin-lead (with increased concentrations and correlation of As, Au, Bi, etc.) when using cassiterite-sulfide ores. The data show the association of the Bronze Age sites of Northern Kazakhstan with the ore and raw materials base in this region, and the intensity of trade exchange of metallurgical products between the Ural and Kazakhstan centers of metal production.

Olonets grasslands (61.041111° N, 32.931389° E) are the most extensive agrolandscapes in the Republic of Karelia (Northwest Russia), one of the largest spring stopovers of migrating birds in Northern Europe and a breeding area of farmland-associated birds. This territory is essential for the life of many bird species and is listed among international-level Important Bird and Biodiversity Areas of Russia. However, the preservation level of Olonets grasslands is rather low, since only spring hunting has been prohibited in a part of the Olonets grasslands (49 km2) since 1993. Thus, the conservation status of this area and the bird protection measures have to be upgraded and a system should be set up for monitoring the abundance of Red Data Book and other threatened species, which use this territory in certain stages of their life cycle. One of such species is Numenius arquata (hereinafter – curlew), many populations of which have both declining abundance and shrinking distribution. This species uses the Olonets grasslands both as a spring migration stopover and as a breeding area. We analysed the curlew registrations obtained in the Olonets grasslands in April and May 1997–2023 during the transect censuses (both transect walks and surveys using a car). We compared these records with both local weather data and grassland use intensity. We also analysed the time dependence of curlew spring abundance on date and year of observations. The research hypothesis was that curlew's abundance decreased in cold spring seasons, in seasons with intensive grassland use, as well as over time. The latter supposition is based on the observations of a curlew population decline in the past decades in various parts of the species' range. The monitoring showed that this species is consistently present in the Olonets grasslands in April – May. Curlews, stopping over on migration, used the grasslands quite evenly, with no clear preference for any specific areas. In the case of breeding, however, they tended to choose the sites most inconvenient for agricultural treatments. The even distribution of curlews over the grasslands was probably due mostly to the individuals foraging in stopovers. In the surveyed part of the Olonets grasslands (49 km2), the size of the local population breeding varied from 30 to 150 pairs in 1999–2023. In 2019–2023, it was 30–90 pairs. In the entire Olonets grasslands (180 km2), the breeding curlew population varied from 100 to 1200 pairs at various years in 1999–2023, but it did not exceed 100–300 pairs in 2019–2023. During the stopping over on migration, the annual number of curlew individuals passing through the surveyed part of the Olonets grasslands was 90–750, while it was 150–2500 birds in the entire Olonets grasslands. So far, we have found no correlation between the total abundance of curlews in the study area and the intensity of grassland use, apparently because stopover and breeding sites are still available. On the other hand, the curlew abundance was lower in warmer spring seasons. Apparently, some curlews fly farther north in such seasons, whereas in colder seasons more birds settle on Olonets grasslands or linger on them on their migration route. Over 25-year retrospective, the total curlew abundance registered in the Olonets grasslands has decreased by 34.4%. In the study area, the negative trend in the species abundance was likely due not only to local but also to global processes, which have caused a decline in some other European populations as well. These birds probably face with certain problems on flyways or in wintering grounds, but more data are needed to verify this conjecture. The local-scope factors that may potentially affect curlew abundance include burning of last year's grass cover, farming intensification, predation, and human disturbance. By assessing possible future changes in the curlew abundance in the Olonets grasslands, we predict that in the coming 30–40 years this species is highly likely to become «endangered» in the study area. To prevent this from happening, it is necessary to conserve the sites where curlews can nest, strengthen the protection regime in the Olonets grasslands (preferably through designation of a high-status Protected Area), and raise public awareness of the need to conserve the species and reduce human disturbance.

Abstract The use of various blood flow control methods in neurovascular interventions is crucial for reducing postoperative complications. Neurosurgeons worldwide use different methods, such as contact Dopplerography, intraoperative indocyanine videoangiography (ICG) video angiography, fluorescein angiography, flowmetry, intraoperative angiography, and direct angiography. However, there is no noninvasive method that can assess the presence of blood flow in the vessels of the brain without the introduction of fluorescent substances throughout the intervention. The real-time laser-speckle contrast imaging (LSCI) method was studied for its effectiveness in controlling blood flow in standard cerebrovascular surgery cases in rat common carotid arteries, such as proximal occlusion, trapping, reperfusion, anastomosis, and intraoperative vessel thrombosis. The real-time LSCI method is a promising method for use in neurosurgical practice. This approach allows timely diagnosis of intraoperative disturbance of blood flow in vessels in cases of clip occlusion or thrombosis. Additionally, LSCI allows us to reliably confirm the functioning of the anastomosis and reperfusion after removal of the clips and thrombolysis in real time. An unresolved limitation of the method is noise from movements, but this does not reduce the value of the method. Additional research is required to improve the quality of the data obtained.

Abstract Magnetotail earthward‐propagating fast plasma flows provide important pathways for magnetosphere‐ionosphere coupling. This study reexamines a flow‐related red‐line diffuse‐like aurora event previously reported by Liang et al. (2011, https://doi.org/10.1029/2010ja015867), utilizing THEMIS and ground‐based auroral observations from Poker Flat. We find that time domain structures (TDSs) within the flow bursts efficiently drive electron precipitation below a few keV, aligning with predominantly red‐line auroral intensifications in this non‐substorm event. The diffuse‐like auroras sometimes coexisted with or potentially evolved from discrete forms. We forward model red‐line diffuse auroras due to TDS‐driven precipitation, employing the time‐dependent TREx‐ATM auroral transport code. The good correlation (∼0.77) between our modeled and observed red line emissions underscores that TDSs are a primary driver of the red‐line diffuse‐like auroras, though whistler‐mode wave contributions are needed to fully explain the most intense red‐line emissions.

Abstract We statistically evaluate the global distribution and energy spectrum of electron precipitation at low‐Earth‐orbit, using unprecedented pitch‐angle and energy resolved data from the Electron Losses and Fields INvestigation CubeSats. Our statistical results indicate that during active conditions, the ∼63 keV electron precipitation ratio peaks at L > 6 at midnight, whereas the spatial distribution of precipitating energy flux peaks between the dawn and noon sectors. ∼1 MeV electron precipitation ratio peaks near midnight at L > ∼6 but is enhanced near dusk during active times. The energy spectrum of the precipitation ratio shows reversal points indicating energy dispersion as a function of L shell in both the slot region and at L > ∼6, consistent with hiss‐driven precipitation and current sheet scattering, respectively. Our findings provide accurate quantification of electron precipitation at various energies in a broad region of the Earth's magnetosphere, which is critical for magnetosphere‐ionosphere coupling.

Abstract Electromagnetic ion cyclotron (EMIC) waves can very rapidly and effectively scatter relativistic electrons into the atmosphere. EMIC‐driven precipitation bursts can be detected by low‐altitude spacecraft, and analysis of the fine structure of such bursts may reveal unique information about the near‐equatorial EMIC source region. In this study, we report, for the first time, observations of EMIC‐driven electron precipitation exhibiting energy, E, dispersion as a function of latitude (and hence L‐shell): two predominant categories exhibit dE/dL > 0 and dE/dL 0 is interpreted as due to an outward radial gradient of the equatorial magnetic field, likely produced by energetic ions freshly injected into the ring current (∼35% of the statistics). The observed energy dispersion of EMIC‐driven electron precipitation was reproduced in simulations.

The modern Arctic is characterized by a decreased ice cover and significant interannual variability. However, the reaction of the High Arctic ecosystem to such changes is still being determined. This study tested the hypothesis that the key drivers of changes in phytoplankton are the position and intensity of Atlantic water (AW) flow. The research was conducted in August 2017 in the northern part of the Barents Sea and in August 2020 in the Nansen Basin. In 2017, the Nansen Basin was ice covered; in 2020, the Nansen Basin had open water up to 83° N. A comparative analysis of phytoplankton composition, dominant species, abundance, and biomass at the boundary of the ice and open water in the marginal ice zone (MIZ) as well as in the open water was carried out. The total biomass of the phytoplankton in the photic layer of MIZ is one and a half orders of magnitude greater than in open water. In 2017, the maximum abundance and biomass of phytoplankton in the MIZ were formed by cold-water diatoms Thalassiosira spp. (T. gravida, T. rotula, T. hyalina, T. nordenskioeldii), associated with first-year ice. They were confined to the northern shelf of the Barents Sea. The large diatom Porosira glacialis grew intensively in the MIZ of the Nansen Basin under the influence of Atlantic waters. A seasonal thermocline, above which the concentrations of silicon and nitrogen were close to zero, and deep maxima of phytoplankton abundance and biomass were recorded in the open water. Atlantic species—haptophyte Phaeocystis pouchettii and large diatom Eucampia groenlandica—formed these maxima. P. pouchettii were observed in the Nansen Basin in the Atlantic water (AW) flow (2020); E. groenlandica demonstrated a high biomass (4848 mg m−3, 179.5 mg C m−3) in the Franz Victoria trench (2017). Such high biomass of this species in the northern Barents Sea shelf has not been observed before. The variability of the phytoplankton composition and biomass in the Franz Victoria trench and in the Nansen Basin is related to the intensity of the AW, which comes from the Frame Strait as the Atlantic Water Boundary Current.

We optimize the internuclear geometry and electronic structure of a model chiral system to achieve a maximal photoelectron circular dichroism (PECD) in its one-photon ionization by circularly polarized light. The electronic structure calculations are performed by the single center method, while the optimization is done using quantum alchemy employing a Taylor series expansion. Thereby, the effect of bond lengths and uncompensated charge distributions on the chiral response of the model is investigated theoretically in some detail. It is demonstrated that manipulating a chiral asymmetry of the ionic potential may enhance the dichroic parameter (i.e., the PECD) of the randomly oriented model system well beyond β1 = 25%. Furthermore, we demonstrate that quantum alchemy is applicable to PECD despite the unusually strong coupling of spatial and electronic degrees of freedom and discuss the relative impact of the individual degrees of freedom in this model system. We define the necessary conditions for the computational design of PECD for real (non-model) chiral molecules using our approach. [ABSTRACT FROM AUTHOR]

Abstract Sub‐auroral polarization streams (SAPS) are one of the most intense manifestations of magnetosphere‐ionosphere coupling. Magnetospheric energy transport to the ionosphere within SAPS is associated with Poynting flux and the precipitation of thermal energy (0.03–30 keV) plasma sheet particles. However, much less is known about the precipitation of high‐energy (≥50 keV) ions and electrons and their contribution to the low‐altitude SAPS physics. This study examines precipitation within one SAPS event using a combination of equatorial THEMIS and low‐altitude DMSP and ELFIN observations, which, jointly, cover from a few eV up to a few MeV energy range. Observed SAPS are embedding the ion isotropy boundary, which includes strong 300–1,000 keV ion precipitation. SAPS are associated with intense precipitation of relativistic electrons (≤3 MeV), well equatorward of the electron isotropy boundary. Such relativistic electron precipitation is likely due to electron scattering by electromagnetic ion cyclotron waves at the equator.

Parker Solar Probe measurements have recently shown that coherent fast magnetosonic and Alfvén ion-cyclotron waves are abundant in the solar wind and can be accompanied by higher-frequency electrostatic fluctuations. In this Letter we reveal the nonlinear process capable of channelling the energy of low-frequency electromagnetic to higher-frequency electrostatic fluctuations observed on board Parker Solar Probe. We present Hall-MHD simulations demonstrating that low-frequency electromagnetic fluctuations can resonate with the ion-sound mode, which results in steepening of plasma density fluctuations, electrostatic spikes, and harmonics in the electric field spectrum. The resonance can occur around the wavenumber determined by the ratio between local sound and Alfvén speeds, but only in the case of oblique propagation to the background magnetic field. The resonance wavenumber, its width, and steepening timescale are estimated, and all indicate that the revealed two-wave resonance can frequently occur in the solar wind. This process can be a potential channel of energy transfer from cyclotron resonant ions producing the electromagnetic fluctuations to Landau resonant ions and electrons absorbing the energy of the higher-frequency electrostatic fluctuations.