Flex Test Research Articles

Characterization of Sex-Dependent Differences in Brain Microvascular Bioenergetics

Background: Women experience increased incidence of stroke-related deaths and lifetime risk of Alzheimer's disease (AD). Microvascular dysfunction has been implicated in the pathogenesis of ischemic stroke and AD. Our objective is to investigate the sex-dependent differences in bioenergetics of young mouse brain microvessels (BMVs). Methods: BMVs were isolated from young male and female mice (3-4 months), using a combination of gradient centrifugation and filtration (300μm and 40μm filters) methods. Extracellular acidification rate (ECAR) and oxygen consumption rate (OCR) of BMVs were measured utilizing the Agilent Seahorse XFe 24 analyzer. The levels of proteins and mRNAs of mitochondrial respiratory complexes were measured by western blot and RT-PCR, respectively. Citrate synthase (CS) enzyme activity and ATP levels were determined in lysates of BMVs. Results: Real-Time ATP Rate assay demonstrated a decreased total ATP production rate and ATP contribution from both glycolysis and oxidative phosphorylation (OxPhos) in BMVs from females compared to males. Mitochondrial stress test assay revealed significantly lower values of several mitochondrial respiratory parameters, including basal respiration, ATP production, maximal respiration, spare respiratory capacity, and proton leak in BMVs from females compared to males. Glycolytic Rate assay uncovered reduced basal glycolysis, proton efflux rate (PER) originating from basal glycolysis, and the mitoOCR/glycoPER ratio in BMVs from females compared to males. Interestingly, no sex-dependent differences were observed in basal PER and post-2-DG acidification rates in BMVs. Mito Fuel Flex Test assay showed no sex-dependent difference in the utilization of glucose, glutamine, and long-chain fatty acids as fuel substrates in BMVs. ATP measurements confirmed the reduced ATP levels in BMVs from females compared to males. Measurements of CS activity revealed no sex-dependent difference in the BMVs. Lastly, Western blot and RT-PCR experiments indicated no differences in either protein or mRNA levels of various mitochondrial complex protein levels.Conclusions: Female BMVs showed reduced mitochondrial respiratory and glycolytic parameters compared to male BMVs although relative contribution of various substrates for energy production were not different. These sex-dependent differences involving glycolysis and OxPhos make the microvasculature vulnerable to injury in females. Funding sources: NIH grants AG074489 and NS114286 (PVGK and RM). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Abstract 1787: The β3-adrenergic receptor as novel target of metabolic phenotype in Ewing sarcoma

Abstract Purpose of study: Metabolic targeted therapies may represent an innovative strategy in Ewing sarcoma (ES). Introduction: Ewing sarcoma (ES) is highly aggressive round cell mesenchymal neoplasm, most often occurring in children and young adults. Metabolic peculiarities of ES cells are indeed involved in tumor growth, survival and resistance to therapy. We have further investigated apoptotic role of 𝜷;;3-adrenergic receptor (𝜷;;3-AR) SR59230A (SR) antagonist for its ability to reduce cells viability due increased oxidative stress, now we underline the metabolic role of SR. Materials & Methods: The metabolic profile after SR administration in A673 ES cell model was studied using the Seahorse XF Analyzer. Viability was evaluated with MTS. Changes in gene expression was evaluated with RNA sequencing. Western blot analysis and Immunofluorescence was performed for redox signature and metabolic alteration. Ros production and cell death was assessed by flow cytometry. Results: Metabolic analysis reveals glucose and fatty acid dependency in A673 cells using the Fuel Flex Test of Seahorse XFe Analyzer. Quantification of transcript abundance using Salmon in A673 after SR treatment showed decrease in response to reactive oxygen species, increase of Thioredoxin Interacting Protein (TXNIP) inhibits the antioxidative function of thioredoxin, moreover reduced glucose uptake, consequently, decrease NADPH/NADP resulting in the accumulation of ROS coincident with a decrease of GLUT1, SOD2, TrDX an increase of LC3IIA protein expression. SR enhances A673 pyruvate dependency, and decrease glyco and mito ATP production rate, more over observed under glucose deprivation. Furthermore, apoptotic effect was significantly amplified when cells were under nutrient starvation, revealing a 56% apoptotic rate after 24 hours of SR treatment. Conclusion: SR antagonist of 𝜷;;3-AR and combination of SR with BUF could be an innovative therapeutic option to raise awareness ES. Citation Format: Cristina Banella, Francesco Carrozzo, Laura Zocca, Amada Pasha, Gianluca Mattei, Marina Mola, Lara Ballerini, Nicla Lorito, Annalisa Tondo, Claudio Favre, Maura Calvani. The β3-adrenergic receptor as novel target of metabolic phenotype in Ewing sarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1787.

Flexible, chemically bonded bismuth/tungsten‐based polyvinyl alcohol‐polyvinyl pyrrolidone composite for gamma and neutron shielding application

AbstractIn this paper, the gamma and neutron shielding behavior of chemically bonded high atomic number (Z), tungsten trioxide‐polyvinyl alcohol‐polyvinylpyrrolidone (PW), and bismuth oxide‐polyvinyl alcohol‐polyvinylpyrrolidone (PB) composites were reported at varying thickness. The PW and PB composites were prepared through the dissolution technique rather than the commonly used dispersion technique. The gamma and neutron attenuation characteristics of the composites were studied using 22Na (0.511 and 1.274 MeV energy) and 252Cf (0–10 MeV energy) sources, respectively. The half value layer of PW and PB composite was found to be 61.22 ± 0.914 mm and 48.29 ± 1.52 mm and the linear attenuation coefficient was found to be 0.115 and 0.144 cm−1 at 0.511 MeV, respectively. Further, the experimental gamma‐ray attenuation results were validated theoretically using Phy‐X software and found to be well in agreement with the experimental data. Both the composites also showed similar neutron shielding behavior when compared to the commercially used high‐density polyethylene (HDPE). The developed composites possess good mechanical properties as they did not show any cracks or wrinkles after undergoing 5400 bending cycles during the flex test, showing their high durability of flexibility. Thus, these composites are found to be suitable for shielding both, the gamma‐rays and neutrons.

Strain-induced damage analysis of hyperelastic material through scanning electron microscopy: A statistical approach using digital image processing

In order to acquire topographic/morphological images with superior resolution and depth of focus than an ordinary optical microscope, scanning electron microscopy (SEM) is used to take photographs of a surface of materials or specimens at a desired point. In the context of polymer and rubber materials science, SEM investigations frequently try to visualize phase morphology, surface and cross-sectional topography, and surface molecular order, and clarify damage mechanisms. In the case of rubber vulcanizates, test specimens are frequently put through a variety of mechanical property assessment procedures, including tensile, flexing, fatigue, abrasion, and tear tests, in order to finalize compounding parameters for required levels of quality. The damaged surface of the test specimens exhibits distinctive topographical characteristics, which are captured as an SEM picture and associated with relevant strength properties. However, the majority of the time, the relationship between strength attributes and the type of surface topography is qualitative. Surface roughness measurement metrics such as root mean square (r.m.s) roughness, average roughness, and peak-to-valley distance are frequently determined for quantitative research using standard software accessible in an SEM. The primary goal of this research is to use a statistical/spectral-based technique for quantitatively measuring surface topography using SEM. The Mullins stress-softening phenomenon of an isotropic, incompressible, hyperelastic rubberlike material is predicted using a phenomenological model. A simple exponential damage function characterizes the model, which represents deformation-induced microstructural degradation of rubberlike material.

Design, manufacturing, and elastic analysis of digital light processing 3D printed fiber reinforced sandwich beams with thermosetting polymer matrix

For the first time, a digital light processing (DLP) three-dimensional (3D) printer is implemented for additive manufacturing of sandwich beams with fiber reinforced facesheets and different core types without using adhesives. After characterizing the formulated thermosetting resin, sandwich beams with honeycomb and square core unit cells were printed in out-of-plane (OP) and in-plane (IP) arrangements, with and without woven glass fiber reinforcement in the facesheets. Meanwhile, using theoretical, micromechanical, and finite element (FE) approaches, the elastic properties and stiffness of sandwich beams were predicted. The stiffness measured from flex tests showed reliable agreement with predictions from analytical and finite element analysis (FEA) for most cases. Additionally, fiber reinforcement significantly increased specific stiffness of these structures, but did not affect the trends for different core geometries. The novel methodology presented here can open new doors for manufacturing advanced structures using DLP 3D printing technology.

Investigation of the Functional Ageing of Conductive Coated Fabrics under Simulated Washing Conditions.

Conductive textiles play an important role in recent electronics development; however, one of the major challenges remains their machine-washing durability. For the investigation of the basic wash ageing mechanisms, we used copper-plated polyamide 66 and cellulose fabrics and developed a wet and dry operable flex tester with online resistance recording. The evaluation was supported by abrasion tests, cyclic elongation tests and tribological investigation of dry and wet textile-textile friction. It was found that the contribution of mechanical and chemical ageing to wash ageing strongly depends on the substrate material. A bad adhesion of copper on polyamide 66 leads to early fatigue while better stability of the copper on cellulose leads to a stronger resistance against ageing. For both substrates, the delamination of the copper layer was the root cause of the fatigue, which is facilitated by the washing solution. Finally, a cumulative fatigue model was developed and the determination of the end of lifetime by the intended use is discussed.

Destructive-Treatment-Free Rapid Polymer-Assisted Metal Deposition for Versatile Electronic Textiles.

Highly conductive, durable, and breathable metal-coated textiles are critical building block materials for future wearable electronics. In order to enhance the metal adhesion on the textile surface, existing solution-based approaches to preparing these materials require time-consuming presynthesis and/or premodification processes, typically in the order of tens of minutes to hours, on textiles prior to metal plating. Herein, we report a UV-induced rapid polymer-assisted metal deposition (r-PAMD) that offers a destructive-treatment-free process to deposit highly conductive metals on a wide variety of textile materials, including cotton, polyester, nylon, Kevlar, glass fiber, and carbon cloth. In comparison to the state of the arts, r-PAMD significantly shortens the modification time to several minutes and is compatible with the roll-to-roll fabrication manner. Moreover, the deposited metals show outstanding adhesion, which withstands rigorous flexing, abrasion, and machine washing tests. We demonstrate that these metal-coated textiles are suitable for applications in two vastly different fields, being wearable and washable sensors, and lithium batteries.

Coal permeability considering mining-induced stresses subjected to fractional derivative

Aiming at characterization of coal permeability under conditions of non-Darcian flow, in the transient pulse test, a new fractional-order decay model is developed to describe the pressure difference decay of coal considering mining-induced stresses. Coal permeability under the condition of mining-induced stress is determined experimentally by the MTS815 Flex Test GT testing machine to validate the fractional-order decay model. The results indicate that the new fractional-order decay model can estimate the permeability of coal considering mining-induced stresses more accurately than the exponential decay model. A conceptual permeability model of coal considering mining-induced stresses is obtained by characterization analysis of coal permeability evolution. Furthermore, the meaning of the fractional order is discussed, showing that it can be used to characterize the influence of mining-induced stresses on the seepage characteristics of coal.

Spontaneous Hybrid Cross‐Linked Network Induced by Multifunctional Copolymer toward Mechanically Resilient Perovskite Solar Cells

AbstractMechanically resilient optoelectronic devices are relevant for a wide range of applications, including portable and wearable devices. Perovskite thin film‐based devices are a suitable choice for designing such resilient systems as it demonstrates high performance while preserving moderate mechanical compliance. Yet its mechanical property can be improved further by integrating the energy dissipation system and self‐healing ability into the thin film. Copolymers containing Lewis‐base functional groups, elastomer chains, and cyclic linkages are synthesized and introduced into the perovskite precursor. The polymers impart multifunctional effect of controlled crystal growth, defect passivation, protection against moisture, mechanical energy dissipation, and self‐recoverability. The polymer‐added perovskite solar cells are shown to provide a power conversion efficiency of 23.25% (a steady‐state efficiency of 22.61%), due to the strong coordinative covalent interaction between the polymer and the perovskite. An operational lifetime of solar cells under harsh conditions is also substantially extended by the polymer incorporation. Furthermore, the interchain hydrogen‐bond strength controlled by the cyclic linkage, and hybrid cross‐linked network formed within the thin film significantly improves the mechanical stability and self‐recoverability of the thin film. As a result, the devices demonstrate robustness under 2000 cyclic flex tests at a bending radius of 1 mm.

Experimental study on mechanical properties, permeability and energy characteristics of limestone from through-coal seam (TCS) tunnel

This paper focuses on analyzing the mechanical properties, permeability and energy characteristics of limestone from coal measures strata of through-coal seam (TCS) tunnel in the context of the Taoziya tunnel as the engineering background. The improved MTS815 Flex test GT rock mechanics system and acoustic emission (AE) technology were utilized for the triaxial compression with permeability test of limestone from coal measures strata of TCS tunnel. The results indicate that gas pressure and confining pressure significantly affect the mechanical properties and permeability of limestone from coal measures strata of TCS tunnel. The gas pressure promotes the development and propagation of cracks, whereas increasing confining pressure strengthens the resistance of limestone samples to crack propagation. When limestone samples transition from the initial compaction stage to the unstable cracks propagation stage, the possibility of gas leakage during tunneling in the coal measures strata should be recognized, and the stability of surrounding rock should focus on the failure stage. In the process of progressive failure of limestone samples, AE events with larger amplitude are distributed near the main macroscopic fracture zone, and the distribution of AE events closely corresponds to the macroscopic failure mode of limestone samples. Exponential functions can be used to describe the trend of initial permeability ki, peak permeability kp and residual permeability kr decreasing with effective confining pressure σe. The closure and propagation of microcracks are the fundamental reason for the corresponding relationship between the stress variation process, AE characteristics and permeability of limestone samples. Finally, the energy characteristics of limestone under triaxial compression were analyzed based on the stress-strain curves of limestone. This study may give fresh insights and necessary references to ensure the safe construction and development of TCS tunnels.

Análise teórica e experimental de lajes pré-fabricadas compostas por vigotas protendidas

ABSTRACT The composite precast slabs are composite systems, in which they are constituted by concrete joists (reinforced or prestressed), filling components and a solidarization layer in reinforced concrete. It is a construction system widely used in the world, mainly in Ibero-American countries, such as Brazil and Spain, for example. However, there is still a lack of knowledge about the compatibility between the theoretical results and the experimental ones, since they are composite systems, and the variables can be decisive in the theoretical models. Therefore, this study aimed to compare the theoretical and experimental results of precast composite slabs. This study developed an experimental program of flexing tests for a slab with pre-stressed center joist reinforced on each side with half-longitudinal slab components and a 5 cm mesh-reinforced concrete cover. Experimental variables were the diameter of steel reinforcement and filler material (ceramic blocks or Expanded Polystyrene – EPS blocks). This study has 4 steps: materials characterization, mechanical tests of the joist, effect of filler material in the structural behavior and theoretical and experimental system behavior at fissuring and rupturing. Prestressed joists ruptured in compression regions during bending tests regardless of the diameter of steel reinforcement due to concrete low strength. Filler material did not alter the slabs rupturing load, but EPS blocks allowed considerable deflections. Regarding maximum bending moment, the selected theoretical models had an agreement of up to 99% on experimental values for 4 mm diameter steel-reinforced joists. However, for the joints with 5 and 6 mm wires, the analysis did not prove to be so valid, reaching a ratio of approximately 70 and 60%, respectively.

SQLE Mediates Metabolic Reprogramming to Promote LN Metastasis in Castration-Resistant Prostate Cancer.

BackgroundAlmost all metastatic hormone-sensitive prostate cancers (mHSPC) will develop into metastatic castration-resistant prostate cancer (mCRPC) after androgen deprivation therapy (ADT). The expression level of squalene monooxygenase (SQLE) is increased in CRPC cells and regulates cholesterol metabolism. This study verified the biological function and mechanisms of SQLE in CRPC.MethodsThe expression of SQLE in human prostate cancer cells was overexpressed or silenced and its efficacy on cell survival was determined by the MTS test. Energy metabolism phenotype test was evaluated by XF real-time ATP rate assay, XF cell mitochondrial stress test, XF glycolysis stress test and XF mito fuel flex test. Cell migration and invasion were evaluated by colony formation assays and transwell assays; the expression of mRNA and protein was assessed by RT-qPCR and Western blot, respectively. Moreover, BALB/c nude mice model was performed to evaluate the lymph node metastasis.ResultsIn our study, we found that the expression level of SQLE was significantly increased in bicalutamide-resistant-C4-2B cells compared to LNCaP cells. SQLE knockdown partly restored the sensitivity of drug-resistant cells to bicalutamide and reduced lymph node metastasis by inhibiting fatty acid oxidation in mitochondria. We also found that terbinafine, the specific inhibitor of SQLE, can enhance the sensitivity of prostate cancer cells to bicalutamide.ConclusionOur study revealed that SQLE is involved in the progression of castration resistance in CRPC through mediating metabolic reprogramming, presenting SQLE as a new target for the treatment of mCRPC.

Use of polymer concrete for large-scale 3D printing

Purpose This paper aims to focus on the evaluation of a polymer concrete as a three-dimensional (3D) printing material. An associated company has developed plastic concrete made from reused unrecyclable plastic waste. Its intended use is as a construction material. Design/methodology/approach The concrete mix, called PolyBet, composed of polypropylene and glass sand, is printed by the fused deposition modelling process. The process of material and parameter selection is described. The mechanical properties of the filled material were compared to its cast state. Samples were made from castings and two different orientations of 3D-printed parts. Three-point flex tests were carried out, and the area of the break was examined. Computed tomography of the samples was carried out. Findings The influence of the 3D printing process on the material was evaluated. The mechanical performance of the longitudinal samples was close to the cast state. There was a difference in the failure mode between the states, with cast parts exhibiting a tougher behaviour, with fractures propagating in a stair-like manner. The 3D-printed samples exhibited high degrees of porosity. Originality/value The results suggest that the novel material is a good fit for 3D printing, with little to no degradation caused by the process. Layer adhesion was shown to be excellent, with negligible effect on the finished part for the longitudinal orientation. That means, if large-scale testing of buildability is successful, the material is a good fit for additive manufacturing of building components and other large-scale structures.

Flexing behaviour of high strength coated fabrics

Flexing characteristics of three varieties of thermoplastic polyurethane (TPU) coated high strength fabrics (nylon 6,6, polyester and kevlar) have been evaluated by subjecting them to 5000 cycles in a De-Mattia flex tester. The flexing damage is assessed in terms of % loss of strength by evaluating the residual tensile strength of flexed fabrics. Statistical analysis has been carried out at 95% significance level for assessing the influence of flexing cycles and variation in thermoplastic polyurethane concentration on the residual strength of coated kevlar fabrics. Accordingly, the specific trend exhibited is established. The study shows that the coated kevlar fabric has suffered with maximum strength loss, while nylon and polyester show excellent flex damage resistance with negligible strength loss. Further, the sensitivity to damage of kevlar fabric has been studied by varying the number of flex cycles from 1000 to 5000 and the extent of damage that happened within the structure is thoroughly analyzed using field emission scanning electron microscope. Finally, the possible mean of improving strength retention (22%) of coated kevlar fabric subjected to repeated flexing by the application of a proprietary high viscosity polymer coating has been proposed.

Strong dark current suppression in flexible organic photodetectors by carbon nanotube transparent electrodes

• Carbon nanotube (CNT) transparent electrode enable high-performance flexible photodetectors. • The CNT-based photodetectors revealed high detectivity owing to high effective electron injection barriers. • Photoelectron yield spectroscopy was used for the analysis of injection model. • The devices demonstrate stable operation after 500 cyclic flex test, attributed to the mechanical stability of CNT. Carbon nanotubes possess outstanding mechanical, optical, and electronic properties and have been proposed as a replacement for indium–tin oxide in curved and flexible organic photodetectors to realize nearly 100% omnidirectional sensing. Because organic photodetectors require dense nanotube arrays to form suitable top layers, it is important to counterbalance their transmittance and packing density to achieve high performance. Carbon nanotubes are introduced as an electrode on a flexible substrate in this study. The carbon nanotube electrode, with an average visible transmittance of 90%, suppresses dark current considerably below the picoampere level, leads to a high detectivity of 2.07 × 10 14 Jones, which is 100 times larger than that of the indium–tin oxide-based devices. The deep work function of the carbon nanotube electrode induced a high electron injection barrier, which was investigated by photoelectron yield spectroscopy, considering the energy level bending caused by the electrode–semiconductor contact. The flexible organic photodetectors fabricated with the carbon nanotube electrode operated stably after a cyclic flex test of 500 bendings. This paper demonstrated the effective implementation of curved and flexible image sensors by developing an excellent flexible photodetector.

Mitochondria as a Platform for Dictating the Cell Fate of Cultured Human Corneal Endothelial Cells.

PurposeAiming to clarify the role of mitochondria in cell fate decision of cultured human corneal endothelial cell (cHCEC) subpopulations.MethodsThe mitochondrial respiratory ability were examined with Mito stress and Mito fuel flex test assays using an extracellular flux analyzer (XFe24; Agilent Technologies; Santa Clara, CA) for human corneal endothelium tissues, mature cHCECs and a variety of cell state transitioned cHCECs. Tricarboxylic acid cycle and acetyl-coenzyme A–related enzymes was analyzed by proteomics for cell lysates using liquid chromatography–tandem mass spectrometry for cHCEC subpopulations.ResultsThe maximum oxygen consumption rate was found to become stable depending on the maturation of cHCECs. In the Mito stress tests, culture supplements, epidermal growth factor, SB203580, and SB431543 significantly repressed oxygen consumption rate, whereas a Rho-associated protein kinase inhibitor Y-27632 increased. Tricarboxylic acid cycle and mitochondria acetyl-coenzyme A–related enzymes were selectively upregulated in mature cHCECs, but not in cell state transitioned cHCECs. The maximum oxygen consumption rate was found to be higher in healthy human corneal endothelium tissues than those with deeply reduced cell density. An upregulated tricarboxylic acid cycle was linked with metabolic rewiring converting cHCECs to acquire the mitochondria-dependent oxidative phenotype.ConclusionsMitochondrial metabolic intermediates and energy metabolism are tightly linked to the endothelial cell fate and function. These findings will help us to standardize a protocol for endothelial cell injection.

Assessment of steel wire’s fatigue life using finite elements modelling and experimental testing

Various applications consist of wire rope as one of their most important construction parts. Wire ropes formed of three parts as basis; wires, strands and core. to get a deep understanding of wire ropes and their mechanical properties, it is essential to study their main part; the wire. For this reason, steel wire has been studied in this work to get its fatigue life as the number of cycles to failure using finite element modeling. FEM results have been verified using experiments; Flex tester machine and fatigue apparatus which is created and structured for this study. Outcomes have proved that using of bigger bending diameters resulted in increasing the fatigue life of the steel wire and vice versa. It is noticed that the FEM results have small and reasonable value of deviation comparing to the experimental results. Other mechanical properties of the steel wire have been obtained from FEM such as; equivalent Von-Mises stress, equivalent elastic strain, equivalent plastic strain and equivalent total strain.

Role of glutamine metabolism in CD8+PD-1+TIM-3+ T cells in ICI resistant melanoma.

e22055 Background: Immune checkpoint inhibitors (ICI) targeting checkpoints has achieved cures in half of stage IV melanoma patients yet there remains a critical need to identify why other half remain either ICI resistant or relapse. Recent studies show that multiple subpopulations of tumor-infiltrating CD8+PD-1+ T cells, previously known to be exhausted, are in fact metabolically active. We have identified a sub population of CD8+PD-1+ T cells resistant melanoma that are metabolically active, highly proliferative; and has high glutamine metabolic pathway. Rapidly proliferating cells utilize the glucose-lactic acid pathway for faster energy production and can metabolize glutamine for energy. A recent study showed that glutamine metabolism blockade improves immunotherapy response by enhancing cytotoxic T cell function. However, the role of glutamine in dysfunctional CD8+T cells has not be studied. Methods: Using patient-derived ICI resistant tumors (n = 8), tumor infiltrating lymphocytes (TILs) were isolated and sorted for total CD8+ T cells for single cell RNA sequencing, and then into CD8+PD-1+TIM-3+ T cells for bulk RNA analysis. FACS analysis was performed to assess the protein expression of SLC1A5 (a major glutamine transporter) and ki67. Seahorse Fuel Flex Test was employed to examine oxidative phosphorylation and mass spectrometry analysis was performed on sorted CD8+PD-1+TIM-3 TILs to assess the glutamine and lactic acid content. Results: A volcanic plot from bulk RNAseq data demonstrated an increase in glutamine pathway activity as well as the expression of SLC1A5 in CD8+PD-1+TIM3+ T cells compared to the peripheral CD8+ T cells. Similarly, scRNAseq analysis showed an increased expression of ki67 and SLC1A5 in MAD CD8+ T cells compared to the effector and naïve CD8+ T cells. FACS analysis of TILs gated for CD3+CD8+,showed an increased protein expression of SLC1A5 and ki67 in the PD-1+TIM-3+ population. A seahorse assay using sorted CD8+PD-1+ TIM3+ TILs from human samples confirmed an increased oxidative consumption rate (OCR) and increased dependency of glutamine metabolism in MAD CD8+ T cells compared to healthy CD8+ T cells. Importantly, mass spectrometry of CD8+PD-1+ TIM3+ T cells showed a significant increase in glutamine and lactate supporting our hypothesis that MAD CD8+ T cells have increased glutamine metabolism due to anaerobic glycolysis. Conclusions: Glutamine is a major metabolic source for rapidly proliferating CD8+PD-1+TIM-3+ dysfunctional T cells and inhibition of glutamine metabolism can be leveraged as immunotherapy in ICI resistant melanoma.

Study on unloading energy characteristics of limestone in different crossing sections

In order to study the energy characteristics of limestone under different initial confining pressures and different unloading rates, based on MTS815 flex test GT rock mechanics test system and acoustic emission (AE) 3D positioning real-time monitoring system, the unloading test and acoustic emission synchronous monitoring of limestone are carried out. The results show that: (1) the pre peak energy process is dominated by energy accumulation, but mainly occurs in the loading stage. The proportion of energy in the unloading stage is basically unchanged, and the proportion of elastic energy is more than 0.9, which fluctuates only before the failure. During the failure, the proportion of energy in the stress drop changes dramatically, and the proportion of elastic energy decreases rapidly to 0. (2) In the coal measure strata, the energy dissipation is the main factor, the dissipation energy and its proportion increase rapidly, while in the front of coal measure strata, the energy release is the main factor, the elastic energy decreases rapidly and the dissipation energy does not increase. (3) The proportion of coal bearing strata in front of coal bearing strata is 0.68 and 0.57 respectively. Unloading elastic energy ratios before coal-bearing strata and coal-bearing strata are 0.824 and 0.876, respectively.

Study on Brazilian Splitting Mechanics and Acoustic Emission Characteristics of Impure Salt Rocks

In order to study the mechanical and acoustic emission characteristics of salt rock under indirect tension, we conducted indirect tension cyclic loading and unloading tests and acoustic emission monitoring on pure salt rock and impure salt rock respectively by using MTS815 Flex Test GT rock mechanics test system and PCI-II acoustic emission (AE) three-dimensional positioning system. The results show that: (1) Both salt rocks show strong plastic deformation characteristics, but the plastic deformation ability of salt rocks is weakened by impurities, which is 79% of the average deformation ability of pure salt rocks. (2) The peak load and tensile strength of impure salt rock are higher than those of pure salt rock. The average peak value is 11.18KN and the average tensile strength is 1.81MPa, which are 1.55 times and 1.60 times of pure salt rock respectively. (3) The indirect tensile deformation characteristics of salt rock can be divided into three stages: damage stage at contact site, tensile deformation stage and post-peak deformation stage. (4) The acoustic emission signal is the most intense near the peak value, but the maximum ring counting rate and energy rate of impure salt rock are higher than those of pure salt rock. (5) When salt rock is destroyed, the whole crack surface is destroyed by tension, but the crack area of pure salt rock is much larger than that of impure salt rock.