Moscow State Pedagogical University

Karkaraly National Park’s pine forests are a important study area for the soil biota within Central Kazakhstan’s dry steppes. Soil zoological research on macrofauna reveals these extrazonal pine forests as refugia for pan-European and Western Palearctic fauna. Microarthropods, however, remain largely unexplored. A recent study of small soil arthropods, particularly springtails, uncovered a new species of the genus Folsomides and the rare Aggressopygus sibiricus, highlighting the faunistic distinctiveness of this area. Six springtail species were recorded for Kazakhstan for the first time, including Asian, Palearctic, and cosmopolitan species. Predominantly eurybiont and forest-dwelling species were found, though many forest-specific genera remain undiscovered. The presence of numerous steppe species like Anurophorus stepposus suggests an ecotone nature of the springtail communities. Surveys across different positions within two forest catenas revealed variations in community composition. Generalized linear mixed models showed a significant relationship between the total number and diversity of springtail species and their position within the catena. The low abundance and species diversity of springtails are likely due to the region’s arid climate and the insular nature of the forests. This supports the island biogeography model, which predicts migration, colonization, and extinction dynamics.

High-frequency terahertz (THz) detectors are vital for next-generation high-speed wireless communication systems. Graphene, with its high carrier mobility, broadband absorption, and weak electron-phonon coupling, offers great promise for ultra-fast THz photothermoelectric devices. Although graphene-based detectors in the infrared range have shown bandwidths above 500 GHz, extending their operation to the THz range is difficult because long-wavelength radiation does not efficiently couple to the small graphene area. To overcome this issue, THz antennas are often employed; however, their use typically limits system performance to only a few gigahertz due to parasitic effects. In this work, we present an antenna-coupled sub-THz graphene detector with a bandwidth exceeding 43 GHz. We optimized the detector design to minimize losses, match the antenna impedance to the 1 kOhm graphene channel, and maintain zero-bias operation. Importantly, we introduce a compact, turnkey packaged solution. Our results provide a practical route toward high-speed and low-power graphene THz detectors suitable for real-world communication and imaging applications.

ABSTRACT Thermoelectric materials, long explored for energy harvesting and thermal sensing, convert heat directly into electrical signals. Extending their application to the terahertz (THz) frequency range opens opportunities for low‐noise, bias‐free THz detection, yet conventional thermoelectrics lack the sensitivity required for practical devices. Thermoelectric coefficients can be strongly enhanced near van Hove singularities (VHS), though these are usually difficult to access in conventional materials. Here it is shown that moiré band engineering unlocks these singularities for THz optoelectronics. Using graphene and bilayer graphene/hexagonal boron nitride (hBN) moiré heterostructures as a model system, a pronounced enhancement of the THz photothermoelectric response is observed when the Fermi level is tuned to band‐structure singularities. Applying a relatively small magnetic field further boosts the response through the THz‐driven Nernst effect, a transverse thermoelectric current driven by the THz‐induced temperature gradient. These results establish moiré superlattices as a versatile platform for THz thermoelectricity and highlight engineered band structures as a route to high‐performance THz optoelectronic devices.

Reconfigurable photonics have rapidly become an invaluable tool for information processing. Lightbased computing accelerators are promising for boosting neural-network learning and inference [X. Xiao Nat. Commun. 15, 6189 (2024)] and optical interconnects are foreseen as a solution to the information transfer bottleneck in high-performance computing [Y. Li et al., in 2021 58th ACM/IEEE Design Automa29, 1 (2022); A. Netherton et al., Photonics Res. 12, A69 (2024)]. In this study, we demonstrate the successful programming of a transformation implemented using a reconfigurable photonic circuit with a nonconventional architecture. The core of most photonic processors is an MZI-based architecture [M. Reck analytical connection between controllable parameters and circuit transformation. However, several archi124, 010501 (2020)] that are substantially more difficult to program have improved robustness to fabrication defects. We use two algorithms that rely on different initial datasets to reconstruct the circuit model of a complex interferometer, and then program the required unitary transformation. The first method is based on the global fitting of the experimental calibration data, while the second method is an ML-based approach introduced in Kuzmin et al. [Opt. Express 29, 38429 (2021)]. Both methods performed accurate circuit programming with an average fidelity greater than 99% and 97%, respectively. Our results provide a strong foundation for the introduction of nonconventional interferometric architectures for photonic information processing.

To introduce noninvasive optical diagnostic methods based on detection of tissue autofluorescence signals into medical practice, it is necessary to correlate the optical response with the functional state of a particular chromophore. Diagnostics of the state of lipofuscin granule chromophores is an important task to assess pathologic changes in the visual system in various diseases, primarily age-related macular degeneration. A key feature of lipofuscin granules (LGs) is the diversity of the chromophores and their susceptibility to oxidation. Here, we used time-resolved emission spectroscopy, confocal fluorescence lifetime imaging microscopy, and high-performance liquid chromatography (HPLC) to follow changes of LG chromophore composition upon photooxidation. In both isolated LGs and LG-loaded retinal pigment epithelium cells (ARPE-19), the distributions of the short lifetime component and its amplitude of LG fluorescence shifted, and the mean lifetime increased upon photooxidation, indicating depletion of population of rapidly relaxing bisretinoids, including A2E, and accumulation of their oxidized species, as confirmed by HPLC data. We applied differential evolution algorithms to decompose LG autofluorescence parameters and identified distinct photooxidation patterns in the presence and absence of antioxidant protection. Delivery of zeaxanthin by water-soluble carotenoprotein ΔNC-AstaP attenuated photooxidation-induced changes in the decay kinetics of both isolated and intracellular LGs, suppressed the accumulation of oxidized bisretinoids, and prevented complete photooxidation. Taken together, our results establish that time-resolved lipofuscin autofluorescence provides a quantitative, label-free readout of chromophore composition and oxidative status that is compatible with functional imaging. We propose that such lifetime-based measurements can be employed for early assessment of retinal pathology and for monitoring antioxidant interventions targeting lipofuscin-induced oxidative stress in emerging clinical techniques such as fluorescence lifetime imaging ophthalmoscopy.