Modeling Experiments Research Articles

SENP2 as a critical regulator in liver ischemia-reperfusion injury.

Liver ischemia-reperfusion injury (LIRI) profoundly affects liver function and survival largely through activation of the innate immune system. In this study we sought to elucidate the underlying mechanisms by which the innate immune system impacts liver function and survival in LIRI. RNA-seq analyses, from existing datasets of liver from mice with LIRI, was performed to identify differentially expressed genes (DEGs) associated with LIRI. Protein-protein interaction analysis revealed clusters involved in signaling pathways with a cluster anchored by Senp2, acting as a central modulator. Macrophages and monocytes were determined to be the source of Senp2 with monocyte-derived macrophages expressing the highest levels of Senp2. Experiments in a mouse model of LIRI further elucidated the expression, function, and mechanism of Senp2. Overexpression of Senp2 suppressed both the polarization of M1 macrophages and the production of inflammatory mediators. Further, Senp2-overexpressing macrophages significantly ameliorated LIRI. Our study suggests that SENP2 plays an important role in regulating LIRI by influencing macrophage polarization through the Dvl2/GSK-3β/β-catenin axis. While further validation is needed, these findings indicate that targeting SENP2-mediated pathways could be a promising approach for mitigating LIRI and enhancing therapeutic strategies.

Binding mechanism of oligopeptides on solid surface: assessing the significance of single-molecule approach.

This paper addresses the complementarity and potential disparities between single-molecule and ensemble-average approaches to probe the binding mechanism of oligopeptides on inorganic solids. Specifically, we explore the peptide/gold interface owing to its significance in various topics and its suitability to perform experiments both in model and real conditions. Experimental results show that the studied peptide adopts a lying configuration upon adsorption on the gold surface and interacts through its peptidic links and deprotonated thiolate extremities, in agreement with theoretical predictions. Single-molecule force spectroscopy (SMFS) measurements revealed the existence of a wide panel of adhesion forces, resulting from the interaction between individual peptide moieties and the abundant surface sites. We therefore propose methodological developments for sorting the events of interest to understand the peptide adsorption mechanism. Thermodynamic and kinetic aspects of the peptide adsorption are probed using both static and dynamic force spectroscopy measurements. Specifically, we show the possibility of providing a reasonable estimate of the peptide free energy of adsorption ΔadsG° by exploring the fluctuations of the adhesion work, based on the Jarzynski equality, and by using a parametric Gamma estimator. The proposed approach offers a relevant method for studying the different factors influencing the peptide adsorption and evaluating their impact on ΔadsG° as an alternative to exploring adhesion forces that may lead to misinterpretations. This is illustrated by the comparison of the adsorption of two peptides with specific amino acids substitution. Our method provides insights into the overall mechanism by which peptides interact with the surface and allows an integration of the single-molecule versus ensemble-average points of view.

Impact of LITAF on Mitophagy and Neuronal Damage in Epilepsy via MCL-1 Ubiquitination.

This study aims to investigate how the E3 ubiquitin ligase LITAF influences mitochondrial autophagy by modulating MCL-1 ubiquitination, and its role in the development of epilepsy. Employing single-cell RNA sequencing (scRNA-seq) to analyze brain tissue from epilepsy patients, along with high-throughput transcriptomics, we identified changes in gene expression. This was complemented by invivo and invitro experiments, including protein-protein interaction (PPI) network analysis, western blotting, and behavioral assessments in mouse models. Neuronal cells in epilepsy patients exhibited significant gene expression alterations, with increased activity in apoptosis-related pathways and decreased activity in neurotransmitter-related pathways. LITAF was identified as a key upregulated factor, inhibiting mitochondrial autophagy by promoting MCL-1 ubiquitination, leading to increased neuronal damage. Knockdown experiments in mouse models further confirmed that LITAF facilitates MCL-1 ubiquitination, aggravating neuronal injury. Our findings demonstrate that LITAF regulates MCL-1 ubiquitination, significantly impacting mitochondrial autophagy and contributing to neuronal damage in epilepsy. Targeting LITAF and its downstream mechanisms may offer a promising therapeutic strategy for managing epilepsy.

A small cavity for detecting sound-induced flow.

A study is presented of a method for creating an acoustic flow sensor that is generally compatible with current silicon microfabrication processes. An aim of this effort is to obtain a design consisting of a minimal departure from the existing designs employed in mass-produced silicon microphones. Because the primary component in all of these microphones is the cavity behind the pressure-sensing diaphragm, we begin with a study of the acoustic particle velocity within a cavity in a planar surface. The sound within the cavity is caused by the external plane sound wave traveling parallel to the cavity's open surface. It is shown that with suitable dimensions of the cavity, the acoustic particle velocity simultaneously flows inward at one end and outward at the other end of the single open cavity surface. A simple analytical model is presented to estimate the required length and depth of the cavity such that the acoustic particle velocity into and out of the opening is a reasonable approximation to that of a plane traveling sound wave in the free field. Measurements of the acoustic particle velocity into and out of the cavity are in close agreement with both the simple model and a more detailed finite element model. Agreement between two dissimilar modeling approaches and experiments suggests that the dominant features of the system have been accounted for. By redirecting the acoustic particle velocity into and out of the cavity opening rather than the flow being parallel to the plane surface, this configuration greatly facilitates the design and fabrication of structures intended to sense the acoustic flow.

Seismic Resilience of Geogrid Reinforced Concrete Earth-Retaining Wall of Various Incremental Panels Based on Physical and Numerical Modelling

The dynamic response for different earth-retaining walls having geogrid as a reinforcement, combined with cohesionless granular material for backfill to mitigate earth pressure, has been examined through scale-down shaking table experiments and full-scale 3D FE analysis, utilizing ABAQUS as the finite element software. The scale factor is 1/4th for scaled-down. This study included various physical modelling experiments using different geogrid-reinforced earth retaining (GRER) walls (1m height, 7.5cm, thickness, and length 1m). Additionally, comprehensive 3D finite element analysis were conducted with the configurations measuring (4m, height 0.3m, thickness, and length 4m). This study examines hollow prefabricated concrete panels with shear key (PC-W), stone masonry walls of gravity type (GM-W), and traditional reinforced concrete (RC-W) walls. It also presents comparative investigations, such as lateral horizontal displacement of the wall, lateral pressure to the backfill, backfill soil settlement, and settlement of the wall foundation of various (GRER) walls. The accuracy of the Finite Element simulation framework has also been assessed in the shaking table experiment, as well as the FE analyses. According to the results, a PC-W wall with a shear key is the most effective type because it shows more resistance toward displacement. As per the comparison of the test models, GRER walls’ seismic response was more affected by the earthquake waves from the far field having long-term high acceleration values. In contrast, seismic waves from the close field had a smaller impact on the walls’ seismic response. However, the geogrid could improve the GRER seismic resilience deformation. Geogrid layers may reduce backfill pressures and backfill settlements. The geogrids located in the central portion within the reinforced soil and the geogrid roots connected to the walls were essential to the seismic design of the geogrid-reinforced earth retaining wall. To evaluate the reliability of the findings, the models have a predicted R2 variance below 0.1, indicating a consistent relationship between these two variables.

Outer membrane vesicles from genetically engineered Salmonella enterica serovar Typhimurium presenting Helicobacter pylori antigens UreB and CagA induce protection against Helicobacter pylori infection in mice

ABSTRACT Helicobacter pylori causes globally prevalent infections that are highly related to chronic gastritis and even development of gastric carcinomas. With the increase of antibiotic resistance, scientists have begun to search for better vaccine design strategies to eradicate H. pylori colonization. However, while current strategies prefer to formulate vaccines with a single H. pylori antigen, their potential has not yet been fully realized. Outer membrane vesicles (OMVs) are a potential platform since they could deliver multiple antigens. In this study, we engineered three crucial H. pylori antigen proteins (UreB, CagA, and VacA) onto the surface of OMVs derived from Salmonella enterica serovar Typhimurium (S. Typhimurium) mutant strains using the hemoglobin protease (Hbp) autotransporter system. In various knockout strategies, we found that OMVs isolated from the ΔrfbP ΔfliC ΔfljB ΔompA mutants could cause distinct increases in immunoglobulin G (IgG) and A (IgA) levels and effectively trigger T helper 1- and 17-biased cellular immune responses, which perform a vital role in protecting against H. pylori. Next, OMVs derived from ΔrfbP ΔfliC ΔfljB ΔompA mutants were used as a vector to deliver different combinations of H. pylori antigens. The antibody and cytokine levels and challenge experiments in mice model indicated that co-delivering UreB and CagA could protect against H. pylori and antigen-specific T cell responses. In summary, OMVs derived from the S. Typhimurium ΔrfbP ΔfliC ΔfljB ΔompA mutant strain as the vector while importing H. pylori UreB and CagA as antigenic proteins using the Hbp autotransporter system would greatly benefit controlling H. pylori infection.

Effects of Polyvinyl Alcohol – Hydroxyapatite Composite Ceramic on Calvarial Defects with Critical Size in Rat Models

Introduction: Biodegradable composite biomaterials are essential in healthcare, effectively tackling numerous complex challenges. Bone reconstruction is a surgical procedure aimed at remedying segmental bone loss, which is notably complicated and often fails to heal properly. A novel bone graft substitute incorporating polyvinyl alcohol (PVA) and synthetic hydroxyapatite (HA) has been developed and is tested in vivo in calvarial defect models of rat. The present study aimed to evaluate the bone regeneration potential of PVA – HA composite bone graft. Materials and methods: A total of 24 adult male Wistar rats aged 12-15 weeks with an average weight of 150 grams were used in the current study. A 4 mm full-thickness critical-size defect was created on the parietal bone and filled with the pre-sized graft material. Radiography, micro-computed tomography, scanning electron microscopy, histology, and serum biochemical parameters, including alkaline phosphatase and acid phosphatase activity, were utilized to evaluate the healing potential of the graft material. The animals were observed for twelve weeks. An immediate postoperative dorsoventral view of the skull was exposed at day zero and subsequent radiographs were taken periodically at weeks 2, 4, 8, and 12 in a group including 24 animals. Results: Immediate post-operative radiographs revealed the radiolucent nature of the graft material. Throughout the healing process, it was observed that the graft remained in position and was intact. The values of serum biochemical parameters alkaline phosphatase and acid phosphatase activity) were haphazard throughout the observation period. In the 8th week, signs of progressive degradation of the graft material and bone regeneration could be seen, particularly on radiography, micro-CT scanning electron microscopy, and histologic examination. Conclusion: It is concluded that the test graft material successfully accelerated bone regeneration and completely integrated with the host bone at week 12 of the experiment in the rat model.

Targeting Enterobacter cloacae attenuates osteolysis by reducing ammonium in multiple myeloma.

Multiple myeloma (MM)-induced bone disease affects not only patients' quality of life but also their overall survival. Our previous work demonstrated that the gut microbiome plays a crucial role in MM progression and drug resistance. However, the role of altered gut microbiota in MM bone disease remains unclear. In this study, we show that intestinal E. cloacae is significantly enriched in MM patients with osteolysis. Through fecal microbial transplantation and single bacterial colonization experiments in a 5TGM1 MM mouse model, we found that intestinal colonization of E. cloacae promotes osteolysis by increasing circulating ammonium levels. Elevated ammonium promotes osteoclastogenesis by increasing Trap protein levels in osteoclast precursors and by acetylating and stabilizing CCL3 protein in MM cells. Inhibition of ammonium synthesis, using E. cloacae with a deleted dcd gene, along with probiotic supplementation, alleviated osteolysis in MM. Overall, our work suggests that E. cloacae promotes osteolysis in MM by synthesizing ammonium. This establishes a novel mechanism and potential intervention strategy for managing MM with osteolysis.

HIGH-FREQUENCY METHODS FOR CALCULATING SCATTERING CHARACTERISTICS OF GROUND-BASED RADAR OBJECTS OF COMPLEX SHAPE

One of the ways to obtain information on the scattering characteristics of ground-based weapons and military equipment in the radar range is mathematical modeling. Mathematical modeling, unlike full-scale and physical experiments, requires significantly less material, organizational and time costs. Radar detection of ground objects is an important component of modern intelligence, surveillance and security systems. They are used to monitor military facilities, vehicles, equipment and personnel on the ground. The main types of radar detection equipment for ground objects are: ground-based radar stations (hereinafter referred to as radars), mobile and portable radars, as well as radar systems installed on board manned or unmanned aircraft.One of the main directions of development of modern offensive weapons and military equipment is the creation of samples of ground (armored) military equipment possessing small values of effective scattering surface. Reduction of radar conspicuity of ground-based military equipment samples is achieved by applying special smoothing forms and covering local areas of the strongest secondary radiation associated with geometro-optical reflection and with scattering on surface fractures with radio-absorbing materials. These measures not only noticeably reduce the energy level of the reflected signal, but also lead to significant changes in other, in particular, polarization characteristics of the target and thus complicate the effective solution of not only detection but also recognition tasks.The article evaluates modern high-frequency methods for calculating the secondary radiation characteristics of complex ground-based radar objects of complex shape by mathematical modeling. The calculation of the scattering characteristics of objects with surface breaks is carried out by preliminary dividing the surface into a smooth part and edge areas of the surface. The considered methods make it possible to evaluate the characteristics of secondary radiation of both a perfectly conductive object located near the boundary of a homogeneous half-space and a ground-based radar object with an imperfectly reflective surface.The application of the presented calculation methods can contribute to obtaining a priori information about the scattering characteristics of ground-based radar objects of complex shape, taking into account such complicating factors as the intra-system interaction “ground object - ground surface”, the presence of radio-absorbing coatings and their complex effect.

Earthquake Nucleation and Slip Behavior Altered by Stochastic Normal Stress Heterogeneity

AbstractIn recent laboratory experiments, varying nucleation locations of accelerating slip with changing nucleation lengths were observed. Spatial variations in effective normal stress, due to the controlling influence on fault strength and fracture energy, play an important role. We quantitatively explain how spatially heterogeneous effective normal stresses affect earthquake nucleation and slip behavior. We simulate a meter‐scale laboratory experiment in a numerical earthquake sequence model with stochastically variable normal stresses. We identify five regimes of earthquake nucleation and slip behaviors, controlled by the ratio of the heterogeneity wavelength to the nucleation length . When , full ruptures are observed. Slip rates and recurrence intervals are similar to those on homogeneous faults with comparable averaged normal stress. When , slow slip events and partial ruptures occur frequently and the nucleation length of each earthquake depends on the local stress level. We find locations of nucleation and arrest in both low and high normal stress regions (LSR and HSR, respectively) when and are of the same magnitude. When , earthquakes nucleate in LSRs, and arrest in HSRs. However, HSRs and LSRs switch these roles when . Interestingly, we observe that nucleation migrates from an LSR to its neighboring HSR in one earthquake, when is between the minimum and maximum local nucleation lengths. We observe a large amount of aseismic slip and associated stress drop in the initial LSR, which might be linked to the migration of foreshocks as documented in natural and laboratory observations. This improved understanding of earthquake nucleation is important in estimating the seismic potential of different fault patches for natural and induced seismicity.

Evaluating the impact of modeling choices on the performance of integrated genetic and clinical models.

The value of genetic information for improving the performance of clinical risk prediction models has yielded variable conclusions. Many methodological decisions have the potential to contribute to differential results. We performed multiple modeling experiments integrating clinical and demographic data from electronic health records (EHR) with genetic data to understand which decisions may affect performance. Clinical data in the form of structured diagnostic codes, medications, procedural codes, and demographics were extracted from two large independent health systems and polygenic risk scores (PRS) were generated across all patients of European ancestry with genetic data in the corresponding biobanks. Crohn's disease was studied based on its substantial genetic component, established EHR-based definition, and sufficient prevalence for training and testing. We investigated the impact of choices regarding PRS integration method, training sample, model complexity, and performance metrics. Overall, our results show that including PRS resulted in higher performance but this gain was only robust in situations with limited clinical information. We find consistent performance increases from more compute-intensive models such as random forest, but the impact of other decisions vary by site. This work highlights the importance of considering methodological decision points in interpreting the impact of PRS on prediction performance in clinical models.

On Using Gssm in Power Systems Dynamics' Simulation

A broad spectrum of aspects related to the feasibility, principles, and implementation of the generalized state-space model (GSSM) as a mathematical modeling technique for energy systems simulation has been considered. This paper reviews the use of GSSM to address the challenges of adequate modeling of dynamics of modern power systems’ dynamics, which are characterized by their hybrid nature, complex switching modes, and nonlinear interactions. The versatility of GSSM is analyzed in comparison to traditional approaches, particularly its capability to integrate continuous and discrete system dynamics into a unified advanced framework. Additionally, the model's ability to capture both linear and nonlinear regimes, its compatibility with contemporary computational tools, and its application across various power systems are discussed in detail. The fundamentals, analytical and numerical considerations of differential-algebraic equations (DAEs) are also examined. The effectiveness of GSSM is demonstrated through a case study involving simulation of a power supply control device dynamics. Computer modeling experiments highlight the advantages of GSSM over traditional methods in terms of accuracy, computational efficiency, and scalability. At the same time, they identify areas where further advancements and improvements are necessary.

MULTILEVEL INVERTER TO GENERATE VOLTAGE WITH COMPLEX HARMONIC COMPOSITION

The paper deals with the problem of forming the desired and controllable harmonic composition of the output curve of a multilevel voltage inverter. The problem is relevant when creating installations for multi-frequency induction heating and metal melting. The purpose of the study is to develop an effective method to form the output voltage of power sources for multi-frequency induction heating installations, the curve of which has a given harmonic spectrum. Materials and methods. The theoretical part of the work was carried out on the basis of the circuit base of multi-level voltage inverters and switching DC converters using numerical analytical methods of studying nonlinear electrical circuits, methods of solving nonlinear differential equations and approximate harmonic analysis, as well as simulation modeling methods using the MATLAB/Simulink mathematical package. Experimental verification of the theoretical results was carried out in laboratory conditions on the example of a multi-level inverter generating a voltage curve with three operating harmonics. ACS758 series sensors and a four-channel RIGOL DS1104Z digital oscilloscope were used to record the results. Research results. Achieving of the purpose is based on the use of a universal multilevel voltage inverter, the circuit scheme of which does not depend on the levels number of the generated curve, which ensures a minimum number of power elements for any complexity of the curve spectrum. The method of forming of the output curve of this inverter consists in alternately connecting of the output capacitors of two direct voltage impulse converters to the input of a single-phase bridge voltage inverter using a transistor switch. In this case, voltages of different parity levels are formed by capacitors in the order of their succession, as a result of which a constant-sign multilevel voltage is formed on the input of the bridge inverter, corresponding to the required alternating-sign multilevel voltage. The law of the transistor switching of the bridge inverter ensures the conversion of its input voltage into a load voltage with a given harmonic composition. The peculiarity of the developed converter control method is that the transistor switching of the bridge inverter is carried out in accordance with the change in the sign of the generated curve. The method contains an algorithm to determine levels values formed by capacitors of impulse converters that realizes the required spectrum of the inverter output curve. The efficiency of the proposed method is illustrated by computer modeling of the converter when voltage with four working harmonics of the spectrum (i.e. the required spectrum harmonics) is generated. The quality indicators of the realized spectrum of the voltage curve are proposed and the analysis results of the influence of the levels number on values of these indicators are presented. The efficiency of the proposed methods is demonstrated experimentally with a laboratory model of the converter. Conclusions. The paper proposes a method to form the output voltage of a power source, the curve of which has a given harmonic, the efficiency of which is confirmed by the results of computer modeling and laboratory experiments. The proposed technical solutions made it possible to generate an output voltage, the spectrum of the curve of which contains four or more harmonics with specified amplitudes with a minimum number of power elements of the circuit. The paper also proposes models of quality indicators of the realized spectrum of the voltage curve and presents the results of the analysis of the influence of the number of levels on the values of these indicators. The developed methodology allows the development in the direction of controlling the spectrum of the generated voltage in real time, as well as non-periodic alternating voltage that changes according to a given program in accordance with the requirements of the technological process.

Exosomes derived from hypoxic mesenchymal stem cells restore ovarian function by enhancing angiogenesis

BackgroundhucMSC-exosomes can be engineered to strengthen their therapeutic potential, and the present study aimed to explore whether hypoxic preconditioning can enhance the angiogenic potential of hucMSC-exosomes in an experimental model of POF.MethodsPrimary hucMSCs and ROMECs were isolated from fresh tissue samples and assessed through a series of experiments. Exosomes were isolated from hucMSCs under normoxic or hypoxic conditions (norm-Exos and hypo-Exos, respectively) and then characterized using classic experimental methods. Based on a series of angiogenesis-related assays, we found that hypo-Exos significantly promoted ROMEC proliferation, migration, and tube formation and increased angiogenesis-promoting molecules in vitro. Histology, immunohistochemistry, and immunofluorescence experiments in a rat model of POF demonstrated that hypoxia pretreatment strengthens the therapeutic angiogenic effect of hucMSC-exosomes in vivo. Subsequently, high-throughput miRNA sequencing, qRT‑PCR analysis, and western blotting were employed to identify the potential molecular mechanism.ResultsWe found that hypo-Exos enhance endothelial function and angiogenesis via the transfer of miR-205-5p in vitro and in vivo. Finally, based on the results of bioinformatics analysis, dual luciferase reporter assays, and gain- and loss-of-function studies, we found evidence indicating that exosomal miR-205-5p enhances angiogenesis by targeting the PTEN/PI3K/AKT/mTOR signalling pathway. These results indicated for the first time that exosomes derived from hypoxia-conditioned hucMSCs strongly enhance angiogenesis via the transfer of miR-205-5p by targeting the PTEN/PI3K/AKT/mTOR signalling pathway.ConclusionsOur findings provide a theoretical basis and demonstrate the potential application of a novel cell-free approach with stem cell-derived products in the treatment of POF.

Модель для контроля качества магнитопроводов линейных электродвигателей на стадии изготовления

The article presents the results of implementing an integrated approach to quality control of linear electric motor inductors at the production stage. The approach is based on the use of mathematical modeling methods and computational experiment. To assess the quality of inductors, it is proposed to use two types of indicators: differential and integral. Differential indicators are determined by conducting a series of experiments with each tooth division of the inductor. Integral indicators allow us to assess the quality of the inductor magnetic circuit as a whole, for which criterion relationships are used. To test the effectiveness of the proposed approach and the reliability of the obtained indicators, a simulation mathematical model of an electric motor inductor with detailing down to one tooth division was developed. Based on this model, an algorithm and a computer program were created that implement the proposed method of quality control during technical testing. The program is written in the Maple software product’s own interpreted programming language and requires the user to enter the parameters of the inductor and power source. As a result of the program, the user receives a conclusion on the quality of the inductor magnetic circuit, as well as numerical values of the differential and integral quality indicators. The materials of the prototype inductor with a high-quality and low-quality magnetic core were used to test the quality criteria using mathematical modeling and computational experiment methods. The results of the experiment confirmed the feasibility of implementing the proposed approach and showed that it adequately reflects the technical quality of inductor magnetic cores. The software product created as a result of the study is intended for technical control of inductor magnetic cores during their production and information support for measures to improve their quality.

Fundamental principles of the effect of habitat fragmentation on species with different movement rates.

Habitat loss and fragmentation have independent impacts on biodiversity; thus, field studies are needed to distinguish their impacts. Moreover, species with different locomotion rates respond differently to fragmentation, complicating direct comparisons of the effects of habitat loss and fragmentation across differing taxa and landscapes. To overcome these challenges, we combined mechanistic mathematical modeling and laboratory experiments to compare how species with different locomotion rates were affected by low (∼80% intact) and high (∼30% intact) levels of habitat loss. In our laboratory experiment, we used Caenorhabditis elegans strains with different locomotion rates and subjected them to the different levels of habitat loss and fragmentation by placing Escherichia coli (C.elegans food) over different proportions of the Petri dish. We developed a partial differential equation model that incorporated spatial and biological phenomena to predict the impacts of habitat arrangement on populations. Only species with low rates of locomotion declined significantly in abundance as fragmentation increased in areas with low (p=0.0270) and high (p=0.0243) levels of habitat loss. Despite that species with high locomotion rates changed little in abundance regardless of the spatial arrangement of resources, they had the lowest abundance and growth rates in all environments because the negative effect of fragmentation created a mismatch between the population distribution and the resource distribution. Our findings shed new light on incorporating the role of locomotion in determining the effects of habitat fragmentation.

Identification of the angles of attack of a hydrodynamic anchor in comparison of numerical and physical experiments

The article is devoted to the urgent task of increasing the effectiveness of rescue operations for the protection of human life at sea by maximizing the drift of rescue vehicles using a hydrodynamic anchor. The paper defines the hydrodynamic characteristics of a hydrodynamic anchor by two different methods: numerical hydrodynamic modeling and physical experiment in a direct experimental pool by pulling a full-scale hydrodynamic anchor with fixed speeds. The identification of the angles of attack of the hydrodynamic armature was carried out in comparison of numerical and physical experiments and the results of calculations of the angles of the working stroke were shown. The angles of installation of the hydrodynamic armature for the angles of attack of the wing, as well as the angles of attack for idling were determined.

Large-scale production of Mansonella perstans infective larvae from engorged Culicoides milnei.

Mansonella perstans is transmitted by Culicoides species and affects hundred millions of inhabitants in about 33 countries in sub-Saharan Africa. It is known that Mansonellosis due to Mansonella perstans do not result in a clear clinical picture, but down-regulates the immunity of patients predisposing them to other diseases like tuberculosis, HIV and malaria or damping vaccine efficacy. However, research about novel drugs against this filarial nematode is missing because of the lack of parasite material. Previous studies have developed in vitro culture systems using infective stage 3 larvae (L3), but these life stages are difficult to obtain and thus the performance of in vitro cultures is restricted and does not allow large-scale testing of drugs or even infection experiments in animal models. Therefore, we aim to establish a platform for the large-scale production of M. perstans infective larvae from engorged Culicoides milnei. Culicoides species were caught in Yangom (Yabassi Health District) in the Littoral Region of Cameroon following a blood meal on six microfilariae-positive donors with different microfilaraemic loads over one year. Engorged midges were reared in the insectarium for up to 14 days and L3 were isolated from the different body parts. In summary, 13,658 engorged Culicoides were collected and reared in the laboratory. We observed an overall predicted survival of 78.5%. Out of the 8,123 survived midges, 7,086 midges belong to C. milnei, from which 2,335 were infected leading to a recovery of 6,310 L3. Moreover, we found the highest survival rates of midges during the early dry season in December with moderate temperatures (23-25°C) and low (2-4mm) or no rainfall. In addition, we observed that midges that fed on donors with high microfilarial loads showed increased mortality. We revealed suitable conditions for the collection and maintenance of engorged Culicoides midges allowing the large-scale production of M. perstans L3. This procedure will provide a platform to produce sufficient parasite material that will facilitate in vitro cultures and the establishment of a murine model of M. perstans, which is important for in-depth investigation of the filarial biology and screening of novel drugs that are effective against this ivermectin-resistant nematode.

Abstract A009: Genetic disruption of CAPNS1 impedes triple-negative breast cancer metastasis: A case for selective calpain-1/2 inhibitors

Abstract Calpains are a family of 15 calcium-activated cysteine proteases that have emerged as potential therapeutic targets in triple negative breast cancer (TNBC). They regulate the function of their substrates via limited proteolytic processing and are involved in both pro- and anti-apoptotic signaling pathways, as well as membrane-cytoskeletal remodeling events associated with cell migration and invasion. The most well-understood members of the calpain family are the classical calpain-1 and calpain-2 isoforms, which are ubiquitously expressed heterodimers each consisting of a large catalytic subunit, encoded by the capn1 and capn2 genes, respectively, and a common small regulatory subunit encoded by capns1. Overexpression of calpain-1 and calpain-2 has been associated with shorter survival in HER2+ breast cancer and TNBC, respectively. We hypothesize that inhibition of calpain-1 and calpain-2 may be exploited to improve tumor response to cytotoxic chemotherapy and suppress metastasis. CRISPR-Cas9 mediated knockout of capns1 in AC2M2 mouse mammary carcinoma cells, which results in a loss of both calpain-1 and calpain-2 activity, disrupts migration and invasion in vitro and impedes lung metastasis in tail vein and orthotopic engraftment mouse models. Calpain knockout also sensitizes AC2M2 cells to the microtubule stabilizing drug paclitaxel, and preliminary results suggest that cancer cell intrinsic calpain depletion may prevent neoadjuvant chemotherapy-induced metastasis. To explore potential off-target effects associated with systemic calpain inhibition, we have established a novel transgenic mouse with conditional deletion of capns1 in its hematopoietic stem cell lineage. By comparing the immune profiles of wild-type and capns1 knockout mice, we aim to better understand how calpain inhibitors will affect various immune cell populations and their respective functions. We plan to extend this understanding to anticancer immunity by conducting tumor immunophenotyping experiments in syngeneic orthotopic engraftment models using wild-type and capns1 knockout mice. At present, no clinically relevant calpain inhibitors are available. However, using genetic approaches, we have validated calpain-1 and calpain-2 as relevant therapeutic targets in TNBC, providing rationale for the development of selective calpain inhibitors. Citation Format: Danielle Harper, Ivan Shapovalov, Samantha Cockburn, Jenny Min, Yan Gao, Peter A. Greer. Genetic disruption of CAPNS1 impedes triple-negative breast cancer metastasis: A case for selective calpain-1/2 inhibitors [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Optimizing Therapeutic Efficacy and Tolerability through Cancer Chemistry; 2024 Dec 9-11; Toronto, Ontario, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(12_Suppl):Abstract nr A009.

Toward human uterus tissue engineering: Uterine decellularization in a non-human primate species.

Uterus bioengineering offers a potential treatment option for women with uterine factor infertility and for mitigating the risk of uterine rupture associated with women with defective uterine tissue. Decellularized uterine tissue scaffolds proved promising in further invivo experiments in rodent and domestic species animal models. Variations in the extracellular matrix composition among different species and adaptations of the decellularization protocols make it difficult to compare the results between studies. Therefore, we assessed if our earlier developed sodium deoxycholate-based decellularization protocol for the sheep and the cow uterus could become a standardized cross-species protocol by assessing it on the non-human primate (baboon) uterus. The baboon uterus was decellularized using sodium deoxycholate, and the remaining acellular scaffold was quantitatively assessed for DNA, protein, and specific extracellular matrix components. Furthermore, electron microscopy deepened morphology examination, while the chorioallantoic membrane assay examined the scaffolds' cytotoxicity, bioactivity, and angiogenic properties. The invitro recellularization efficiency of the scaffolds using xenogeneic (rat) bone marrow-derived mesenchymal stem cells was also assessed. Finally, the immune potential of the scaffolds was evaluated by invitro exposure to human peripheral blood mononuclear cells. We obtained a decellularized baboon uterus with preserved extracellular matrix components by adding an 8-h sodium deoxycholate perfusion to our previously developed protocol for the sheep and cow models. This minor modification resulted in scaffolds with less than 1% of immunogenic host DNA content while preserving important uterine-specific collagen, elastin, and glycosaminoglycan structures. The chorioallantoic membrane assay and invitro recellularization experiments confirmed that the scaffolds were bioactive and non-cytotoxic. As we have observed in other animal models, the enzymatic scaffold preconditioning with matrix metalloproteinases improved the recellularization efficiency further. Additionally, the preconditioning generated more immune-privileged scaffolds, as shown in a novel invitro co-culture assay with human peripheral blood mononuclear cells. For the first time, our data demonstrate the efficiency of our protocol for non-human primate uteri and its translational potential. This standardized protocol will facilitate cross-study comparisons and expedite clinical translation.