Size Structure Research Articles

Size effect on CFST-column seismic performances at cryogenic temperature via mesoscale simulations

The macro-mechanical performances of CFST column at low temperatures can be significantly affected by three main factors: the change of meso-material properties, the filling and frost heave effects caused by pore ice, and the interaction between each meso-component. Therefore, a three-dimensional thermo-mechanical sequential coupling mesoscopic simulation method was established and verified by existing experimental results with the maximum errors within 10 %. The seismic performances of CFST columns with various cross-section sizes (200–800 mm) at different temperatures (20, −30, −60 and − 90 °C) were simulated and investigated, with focused on the damage mechanism and quantitative analysis of the low-temperature effect on various seismic performance indexes (i.e., hysteretic characteristic, nominal shear strength, ductility, energy dissipation and reparability) as well as the corresponding size effects. The results indicate that the low temperature can increase the nominal strengths (i.e., peak strength, yield strength and ultimate strength), but weaken ductility, energy dissipation capacity and reparability of CFST columns. With the increase of cross-section size, the reparability increases, while other seismic performance indexes decrease, showing the size effect, which tends to be more obvious at low temperatures. The size effect on peak strength at −90 °C is enhanced by 115.5 % than that at 20 °C, while 127.9 % for yield strength and 113.5 % for ultimate strength. Based on research results, a modified size effect formula for calculating shear strengths of CFST columns considering the influence of low temperature and structural size was developed, which can provide references for seismic design of large-sized CFST columns in extreme low temperature environments.

Modeling ground vibration excited by a high-speed train running along a viaduct railway using a new structure-soil interaction method

Ground vibrations generated by high-speed trains running along railways either at grade or on viaduct bridges, are greatly concerned by the railway industry. Considering the train-track-bridge-abutment-pile-soil interactions involved, modeling the problem in an analytical manner is almost impossible, while conventional numerical methods struggle to accurately simulate the dynamic properties of infinitely large soils. Therefore, this study introduces a new substructure methodology for train-track-bridge-abutment-pile-soil interactions that leverages an ingenious combination of the 2.5-dimensional finite element-boundary element method (2.5D FE-BE) for dynamics of infinitely long periodic structures, and a local 3-dimensional finite element model for pile-soil interaction. This innovative method allows for the consideration of detailed pile-soil coupling using a local finite element model, all while retaining the ability to account for the infinite size of the soil structure using the 2.5-dimensional finite element-boundary elements. After a comparison between model prediction and field measurement, the model is employed to explore the environmental vibration characteristics of on-viaduct high-speed railways and analyze the vibration reduction effects of various measures, including rail fasteners, track slab pads, and bridge bearings.

Influence of structure-soil-structure interaction on seismic response and seismic migration performance of building structures

Increasing numbers of complex structure systems with underground structures crossing a cluster of aboveground structures are being constructed in densely populated urban areas. The complex dynamic interaction between the underground structure, aboveground structure, and the surrounding soil, is called structure-soil-structure interaction (SSSI). The SSSI effects bring challenges to the seismic design of such complex structure systems. This study aims to analyze the influence of adjacent aboveground and underground structures on seismic response and seismic migration performance of building structures using dynamic finite element simulations. The direct method is used to establish structures and soil. A comprehensive numerical analysis is first presented to study the impact of adjacent aboveground and underground structures on target building structures by varying the distance, form, and size of adjacent structures, etc. Then, the seismic migration performance of building structures equipped with the tuned mass damper (TMD) is investigated. The numerical results indicate that the presence of adjacent aboveground structures has a limited impact on the seismic response of the target structure. The seismic response of the target structure is significantly affected by the adjacent underground structures. The TMD designed according to the traditional method may be detuned when the SSI effect is significant. The TMD performance is improved by considering the adjacent structures.

Ring/vortex-like extreme wave in the partially nonlocal medium with different diffraction characteristics in both directions under influence of external potential and gain/loss

In this study, we analyze a (3+1)-dimensional partially nonlocal nonlinear Schrödinger (NLS) model, which incorporates various diffraction effects, gain or loss mechanisms, and confinement within linear and parabolic potentials. By reducing this complex model to a (2+1)-dimensional framework, we uncover analytical solutions that exhibit high-dimensional extreme wave structures with Hermite-Gaussian envelopes, illustrating the model's nonautonomous characteristics. Our investigation focuses on ring-like and vortex-like extreme waves, examining how different parameters—such as radius, Hermite parameter, gain, and thickness—affect these wave structures. Specifically, we find that, for fixed thickness, Hermite, and gain parameters, the radius influences the size of the wave structures. Conversely, with a fixed radius, Hermite, and thickness parameters, the gain parameter modifies the wave properties. The introduction of the Hermite parameter p increases the number of concentric layers in the ring-like extreme waves by p+1. Additionally, incorporating gain and loss effects enhances the model's applicability to real-world scenarios.

High-Dimensional Bayesian Semiparametric Models for Small Samples: A Principled Approach to the Analysis of Cytokine Expression Data.

In laboratory medicine, due to the lack of sample availability and resources, measurements of many quantities of interest are commonly collected over a few samples, making statistical inference particularly challenging. In this context, several hypotheses can be tested, and studies are not often powered accordingly. We present a semiparametric Bayesian approach to effectively test multiple hypotheses applied to an experiment that aims to identify cytokines involved in Crohn's disease (CD) infection that may be ongoing in multiple tissues. We assume that the positive correlation commonly observed between cytokines is caused by latent groups of effects, which in turn result from a common cause. These clusters are effectively modeled through a Dirichlet Process (DP) that is one of the most popular choices as nonparametric prior in Bayesian statistics and has been proven to be a powerful tool for model-based clustering. We use a spike-slab distribution as the base measure of the DP. The nonparametric part has been included in an additive model whose parametric component is a Bayesian hierarchical model. We include simulations that empirically demonstrate the effectiveness of the proposed testing procedure in settings that mimic our application's sample size and data structure. Our CD data analysis shows strong evidence of a cytokine gradient in the external intestinaltissue.

Metamaterial-based Artificial magnetic conductor for efficient breast cancer diagnosis using a low-cost antenna array.

Breast cancer is the most common malignancy in women globally, stemming from gene mutations that prompt irregular cellular growth and subsequent tumor development. Early-stage detection of cancer cells results in a remarkable 99% survival rate. This research presents a microwave imaging technique for the non-invasive identification of tumors in the initial stages within the women's breast. A low-cost antenna array with an Artificial Magnetic Conductor (AMC) is proposed, featuring a compact structure size of 37.2 37.2 mm . The AMC, a metamaterial, acts as a reflective surface to enhance frequency selectivity, specifically at 8.48 GHz. The maximum gains reached 9.35 dBi in simulated results and 10.51 dBi in measured results. The fabricated antenna validates the simulated findings, and its operational efficiency has undergone experimental validation. Moreover, fidelity factors in face-to-face (FtF) and side-by-side (SbS) scenarios are delineated. The antenna, operating as a transceiver, is applied to a modeled breast phantom across five distinct cases for numerical simulations pertaining to cancer cell detection applications. The outcomes of this research bear considerable implications for advancing early-stage breast cancer detection methodologies.

Miniaturized on-chip optical differentiator based on 2F-structured metasurfaces.

Analog optical computing based on Fourier optics has attracted ever-growing attention, offering unprecedented low power consumption and high parallelism computation at the speed of light. Typically, classical optical 4F systems have been widely employed as one of the most common approaches for analog optical computing. However, most existing schemes replicate the original architecture relying on two Fourier transforms and one spatial-frequency filtering, resulting in bulky size and complex structure. Here, we propose a novel, to the best of our knowledge, on-chip 2F structure that achieves ultra-miniaturized optical analog computing. Taking advantage of the exceptional design flexibility of metasurfaces, we reduce the optical path length through a combination of phase compensation and complex amplitude modulation, thereby significantly simplifying the system structure without sacrificing accuracy compared to the traditional 4F system. As a proof-of-concept demonstration, we design and fabricate an on-chip optical differentiator on a silicon-on-insulator platform, achieving 84.01% and 79.81% differentiation accuracy in simulation and experiment, respectively.

Evaluation of the impact of hollow fiber pore size and membrane material on virus concentration using a handheld hollow fiber method.

Virus concentration using hollow fibers is widely used for vaccine production to maintain viral infectivity with low shear stress and to allow for easier scale-up of production. However, research laboratories often have limited available viral materials at the early stage of vaccine development, making it difficult to find an optimal hollow-fiber. In addition, few research articles have reported on optimizing hollow fiber pore size and membrane structure for virus concentration. In this study, the previously established handheld hollow fiber virus concentration method was modified to reduce the sample volume required and to enable simple and easy hollow fiber screening. The handheld hollow fiber screening method for virus concentration was confirmed to be effective using Zika as a model virus.

Morphological Characterization of an Eco Friendly Medi Grade Bio-Polymer Composites Using SEM Analysis

ABSTRACT Background: Medical and Dental Implant Biomaterial Research is focused on the cutting-edge interface of polymer composite material. Ongoing research and development in the bio-material field are focused on novel matrix-filler formulations of polymer composite material with improved properties in near future. Aim: This study focuses on the morphologic characterization and structural analysis of three different volume fraction of novel natural filler basalt reinforced with PEEK polymer. Materials and Methodology: The composite samples are prepared with three different volume fraction of basalt fiber in PEEK matrix, such as PBC1 having 90% PEEK and 10% basalt, PBC 2 having 80% PEEK and 20% basalt, and PBC 3 having 70% PEEK and 30% basalt. The basalt fiber influence in the composite was investigated using Scanning Electron Microscope (SEM) and X- Ray Diffraction (XRD) analysis. The crystalline structure and the grain size were examined by X-Ray diffraction method. Result: The SEM images reveal that PBC2 composite exhibits perfect bonding and less voids compared to pure PEEK, PBC1 and PBC3 composites. Conclusion: The study reports that 80% PEEK and 20% basalt fiber composite shows better structure and grain size compared to other samples with different proportions.

Axial mechanical properties of welded orthogonal trapezoidal aluminum honeycomb as filler material for nuclear equipment impact limiter.

Lightweight porous structural materials have excellent energy absorption performance, and their application are gradually appeared. This paper takes the shock-absorbing material of nuclear equipment transportation casks as the starting point, and manufactures an orthogonal trapezoidal aluminum honeycomb by welding (WOTAH). The mechanical properties with different cell thicknesses and cell size ratios under different impact loads are studied through experimental and simulation methods, and the deformation process and energy absorption performance of the materials are obtained. The energy absorption performance of materials under quasi-static loading was investigated using plastic deformation theory and compared with experimental results. Based on the experimental results, the least squares method was used for data fitting to obtain the C-S dynamic constitutive relationship of the material. The equivalent structure was used to replace the honeycomb structure for simulation, and the influence of strain rate effect and structural size on material properties was further studied. Through the above mechanical performance analysis and comparison with wood, it is shown that WOTHA has feasible for the application of nuclear equipment impact limiter.

Abstract 4123926: Suprasomatic Serial Growth of Right Heart Structures in Fetuses with Hypoplastic Left Heart Syndrome Demonstrated by Fetal Echocardiography

Background: In hypoplastic left heart syndrome (HLHS), the single right ventricle (RV) accounts for the entire cardiac stroke volume. This physiology may produce elevated transpulmonary flow velocities and dilation of the right heart structures. Little data exists regarding normal right heart dimensions and transpulmonary velocities in relation to somatic growth in these fetuses. We sought to assess serial changes in the size of right heart structures and pulmonary valve (PV) velocities in fetuses with HLHS and compare findings to fetuses with normal cardiac anatomy. Methods: A retrospective cohort study of fetuses with HLHS or normal cardiac anatomy confirmed by fetal echocardiogram between 1/1/13 – 12/31/22 was performed, excluding multiple gestation pregnancies. Fetal echocardiograms were assessed by an independent reviewer who obtained RV, PV and tricuspid valve annulus dimensions, and PV flow velocities. Nomograms were created for both HLHS and normal cohorts. The association between gestational age and PV velocity, PV annulus, RV diameter and tricuspid valve annulus was assessed and compared between groups using linear mixed models. Results: There were 290 total fetal echocardiograms for 177 patients with HLHS compared against 408 normal fetuses. [MG1] PV velocities were higher for patients with HLHS compared to normal cardiac anatomy throughout gestation (p < 0.001). In addition, the PV velocity increased more rapidly with gestational age for the HLHS (+0.02 m/s/week) group compared to those with normal cardiac anatomy (+0.01 m/s/week) (p=0.019) (Figure 1). Similarly, the RV dimension grew more rapidly with gestational age for those with HLHS (+3.2% cm/week) compared to those with normal cardiac anatomy (+2.5% cm/week) (p<0.001) (Figure 2). Lastly, the tricuspid valve annulus grew more rapidly with gestational age for patients with HLHS (+2.6% cm/week) compared to those with normal cardiac anatomy (+2.3% cm/week) (p=0.010) (Figure 3). While the PV annulus size increased with gestational age, there was not a significant difference in growth between the two groups (p=0.119). Conclusions: In fetuses with HLHS, the PV velocity, RV size and tricuspid valve size increase at a rate greater than normal somatic growth. These nomograms help identify expected RV size, tricuspid valve size and PV velocities for fetuses with HLHS and any who may deviate from the norm.

Multifunctional Electromagnetic Responsive Porous Materials Synthesized by Freeze Casting: Principles, Progress, and Prospects

AbstractFreeze casting is a solidification technique utilized in the fabrication of porous materials. However, the freeze casting process is quite complex, and significant challenges remain in precisely controlling the pore size and shape of porous structures. This study aims to investigate the customization of multifunctional electromagnetic wave (EMW) absorbers with 3D porous structures via freeze casting. This review initially presents the fundamental principles underlying the freeze casting technique and examines the correlation between internal and external factors during the preparation process and porosity. The emerging trends in constructing novel and intricate macroscopic structures through freeze casting are subsequently outlined. Furthermore, this review focuses on the fabrication of composites with various porous microstructures through freeze casting of low‐dimensional building blocks, and their EMW response and multifunctional properties. By regulating the internal and external influencing mechanisms of freeze casting, porous EMW absorption materials exhibit outstanding advantages such as electromagnetic property manipulation, controllable structure, high porosity, high specific surface area, lightweight, and flexibility. These features broaden their applications in electromagnetic shielding, mechanical property, radar stealth, thermal insulation and fire prevention, flexible sensors, antifreeze ability, etc. In addition, we discuss the challenges and prospects of high‐performance EMW absorbers using freeze casting techniques.

Distinct types of VHHs in Alpaca

IntroductionVHHs (VH of heavy-chain-only antibodies) represent a unique alternative to Q7 conventional antibodies because of their smaller size, comparable binding affinity and biophysical properties. MethodIn this study, we systematically analyzed VHH NGS sequences from 22 Alpacas and structure data from public database. ResultsVHHs in Alpaca can be grouped into five main types with multiple distinct sequence and structure features. Based on the existence of hallmark residues in FR2 region, VHHs can be classified into two groups: nonclassical VHHs (without hallmark residues) and classical VHHs (with hallmark residues). Based on VHH hallmark residues at 42 position (IMGT numbering, FR2 region) and number of cysteines, we found that Alpaca classical VHHs can be further separated into three main types: F_C2 VHHs with F (phenylalanine) at position 42 and having 2 cysteines within sequences, Y_C2 VHHs with Y (tyrosine) at position 42 and having 2 cysteines, and F_C4 with F at position 42 and having 4 cysteines. Non-classical VHHs can be further separated into 2 types based on germlines mapped: N_V3 for VHHs mapped to V3 germlines and N_V4 for V4 germlines. Based on whether FR2 residues are involved in binding, two kinds of paratopes can be identified. Different types of VHHs showed distinct associations with these two paratopes and displayed significant differences in paratope size, residue usage and other structure features. DiscussionSuch results will have significant implications in VHH discovery, engine e ring, and design for innovative therapeutics.

Abstract 4138380: Cardiac protection of hiPSC-CMs loaded chitosan cardiac patch in myocardial infarcted swine

Background: The low grafting rate of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) following direct injection into the myocardium limits the efficacy of cardiac repair after myocardial infarction (MI). Chitosan-based scaffolds have emerged as functional biomaterials for designing delivery systems in cardiac therapies. This study aimed to enhance the potency of cardiac repair using a hiPSC-CMs loaded chitosan cardiac muscle patch (hCCMP). Methods: The patches were fabricated using chitosan. Characterization of the chitosan patches involved assessing their swelling rate and porosity. The biocompatibility of the hCCMP was analyzed through scanning electron microscopy (SEM) and the CCK8 assay. 16 Yorkshire swine (15-20 kg, 45-50 days of age) were randomly divided into 4 groups (n=4 per group): Sham, MI without further intervention, MI with an empty patch (without hiPSC-CMs), and MI with hCCMP implantation. One and four weeks post-MI, heart function, Infarction size, myocardial perfusion and metabolism were evaluated via cardiac PET-MRI. Engraftment was assessed through human cardiac troponin T staining. Histological analysis including left ventricular anterior wall thickness, cardiac remodeling, angiogenesis, arterialization, and apoptosis in the infarct border area were analyzed using immunofluorescence. Results: SEM showed that the chitosan patch had regular pore size and good 3D structure; porosity was about (96.7±0.37)%. On day3, the patch swelling rate was about (715±64.55)%. SEM, CCK8 assay showed a normal cells growth in the chitosan patch. The hiPSC-CMs grafted well with chitosan patch delivery systems and was associated with significantly improvement in LV function, infarction size, angiogenesis and cardiomyocyte apoptosis in pigs 4 weeks after MI. Conclusions: The 3D chitosan cardiac patch with hiPSC-CMs loaded can enhance the potency of cardiac repair in pigs after MI and present a novel and promising therapic strategy.

Resilience of Phytoplankton and Microzooplankton Communities under Ocean Alkalinity Enhancement in the Oligotrophic Ocean.

Ocean alkalinity enhancement (OAE) is currently discussed as a potential negative emission technology to sequester atmospheric carbon dioxide in seawater. Yet, its potential risks or cobenefits for marine ecosystems are still mostly unknown, thus hampering its evaluation for large-scale application. Here, we assessed the impacts OAE may have on plankton communities, focusing on phytoplankton and microzooplankton. In a mesocosm study in the oligotrophic subtropical North Atlantic, we investigated the response of a natural plankton community to CO2-equilibrated OAE across a gradient from ambient alkalinity (2400 μmol kg-1) to double (4800 μmol kg-1). Abundance and biomass of phytoplankton and microzooplankton were insensitive to OAE across all size classes (pico, nano and micro), nutritional modes (autotrophic, mixotrophic and heterotrophic) and taxonomic groups (cyanobacteria, diatoms, haptophytes, dinoflagellates, and ciliates). Consequently, plankton communities under OAE maintained their natural chlorophyll a levels, size structure, taxonomic composition and biodiversity. These findings suggest a high tolerance of phytoplankton and microzooplankton to CO2-equilibrated OAE in the oligotrophic ocean. However, alternative application schemes involving more drastic perturbations in water chemistry and nutrient-rich ecosystems require further investigation. Nevertheless, our study on idealized OAE will help develop an environmentally safe operating space for this climate change mitigation solution.

SURG-56. TRANSCRIPTION FACTOR CELL LINEAGE DETERMINES AGGRESSIVE BEHAVIOR AMONG NONFUNCTIONAL PITUITARY ADENOMAS

Abstract INTRODUCTION Pituitary neuroendocrine tumors (PitNETs) are the second most common intracranial neoplasm. Silent or non-functional PitNETs represent a common neuro-oncological challenge due to their size and unpredictable invasion of parasellar structures. This makes their complete surgical resection difficult and puts patients at higher risk for recurrence. OBJECTIVE To characterize differences in tumor volume, cavernous sinus invasion, and recurrence in nonfunctional PitNETs. METHODS Out of 615 transsphenoidal surgeries from 2012 to 2024, there were 309 overall PitNETs and 181 nonfunctional PitNETs. Based on new WHO criteria for transcription factor profiling (PIT-1, TPIT, and SF-1), there were 98 silent gonadotroph adenomas (SGA), 31 silent corticotroph adenomas (SCA), 10 silent pleurihormonal tumors (PHT), and 2 null cell adenomas. Tumor volume was calculated using (AxBxC/2). Knosp grade was calculated. Cavernous sinus invasion was defined as Knosp ≥ 3. Residual disease at 3 months postoperative was recorded and surgical intervention for growing residual disease was captured. RESULTS Average tumor volume of PHT (18.08 cm3) was significantly higher than SGA (8.44 cm3, p=0.007) and similar to SCA (10.33 cm3, p=0.11). Percentage of cavernous sinus invasion was significantly different between SCA (31.82%) and SGA (10.20%, p=0.003), but not PHT (33.33%; p>0.05). There was a significantly higher residual rate in SCA compared to SGA (31.71% vs. 11.22%, p=0.006). There were significantly more reoperations in the SCA group compared to SGA and PHT. CONCLUSIONS Despite similar tumor volume between SCA and SGA, there was a significantly higher rate of cavernous sinus invasion and residual disease among SCA. This has important neuro-oncological implications regarding surgical technique, postoperative surveillance, and need for adjuvant therapy to mitigate aggressive recurrent disease.

Interactive Effects of Anthropogenic Stressors on the Temporal Changes in the Size Spectrum of Lake Fish Communities

ABSTRACTThe size spectrum represents a powerful approach for quantifying the effects of environmental changes from individuals to communities in aquatic ecosystems. However, our understanding of its temporal stability in freshwater ecosystems is still limited. In the present study, we used a size spectrum approach to investigate the responses of 126 lake fish communities to changes in the intensity of three common anthropogenic stressors (i.e., global warming, nutrient loading and biological invasions) in French natural lakes and reservoirs over an average 5‐year time period. Using a backward selection on a full model including all possible effects of stressors on the size spectrum slope, we demonstrated that (i) increasing summer temperature shifted fish abundance towards the largest size classes, resulting in a flatter size spectrum slope and (ii) nutrient loading and biological invasions were associated with a shift towards smaller size classes in natural lakes, while the opposite effect was observed in reservoirs. In addition, these two stressors interacted in determining changes in the size structure of fish communities, complicating what the size spectrum can reveal about changes in stressor intensity during monitoring programs. All predictors accounted for a limited part of the observed changes in size spectra, and further investigations are needed to fully apprehend the interplay between natural and human‐induced drivers of the temporal changes in size spectra in contrasting environmental conditions.

Length‐Based Assessment of Hovsgol Grayling (Thymallus nigrescens), Lenok (Brachymystax lenok), and Burbot (Lota lota) Population Status in Lake Hovsgol, Mongolia

ABSTRACTDespite the global importance of inland fisheries, data available for stock assessment is often limited. Data‐limited methods that use length composition data offer a potential approach to assessing more inland fisheries. We assessed the population status of three fish species in Lake Hovsgol, Mongolia through length‐based spawning potential ratio (LBSPR) analysis and evaluation of trends in eight length‐based indicators of population status, catch‐per‐unit‐effort (CPUE), and body size. Hovsgol grayling (Thymallus nigrescens) were not yet overfished, but CPUE and body size declined due to targeting of large, mature fish. Lenok (Brachymystax lenok) were experiencing overfishing, especially of small, immature fish, which contributed to size–structure truncation. The burbot (Lota lota) population was healthy according to most indicators, but the lack of local life history information exacerbated already large uncertainties. Continued monitoring and improved coordination among fishers, managers, and scientists will be critical to enhancing the sustainability of these fisheries.

Balanced Rh+‐Rh0 Sites over Rh Clusters Enhance Heterogeneous Hydroformylation of Aldehyde

AbstractControlling the metal geometric and electronic structure is of significance in developing efficient catalysts for heterogeneous hydroformylation. This study examines the structural sizes of Rh and Rh+‐Rh0 distribution to construct a highly active catalyst for formaldehyde hydroformylation. The active sites for hydroformylation require several Rhn atoms, while single‐atom Rh can solely catalyze hydrogenation. The highest activity was achieved on Rh nanoclusters (0.95 nm), giving a TOF of 191 h−1 and selectivity of 82% for glycolaldehyde formation. The tunability of the electronic properties of Rh nanoclusters and the synergistic interaction between Rh+ and Rh0 are essential for enhanced activity. Pseudo‐in situ FT‐IR analysis elucidated that formaldehyde adsorbed on Rh nanocluster prefers to produce glycolaldehyde via hydroformylation, while formaldehyde adsorbed on isolated Rhδ+ sites tends to form methanol via hydrogenation. This study provides a new insight into the design of heterogeneous catalysts and guidance for understanding the reaction mechanism for aldehydes/olefins hydroformylation.

Spongillidae (Porifera, Spongillidae) in the Subarctic of Western Siberia

When studying the zooperiphyton of reservoirs and watercourses in the Subarctic of Western Siberia, freshwater sponges were identified. The research was carried out in areas of the southern tundra and forested tundra belts, which in turn were conditionally divided into three zones: western, central and eastern. In total, the research covered 40 reservoirs and watercourses. Three species of sponges have been found: Spongilla lacustris, Ephydatia muelleri and Ephydatia fluviatilis. The most common species is S. lacustris, E. muelleri being less common, vs E. fluviatilis which occurs only occasionally. The maximum numbers of species and their occurrence were noted in forested tundra water bodies. Linear measurements and a dimensional analysis both of gemmules and elements of the skeleton of the sponges were carried out. A tendency was revealed to a decrease in size of the skeletal structures of the studied biological material in comparison with literature data.