Raft Structure Research Articles

Mechanical characteristics analysis and control algorithm for floating raft system with mass variation

The ship floating raft system adopts the integrated design of large liquid tanks and rafts, which can optimize the arrangement in the cabin and increase the intermediate mass of the system to achieve efficient vibration isolation of equipment. One of the major challenges is that the change of liquid mass in the tank will cause displacement of the raft, which will change the modal characteristics of the system and affect the stability of the vibration isolation system performance. This paper establishes a mechanical analysis model of a floating raft system under time-varying liquid mass conditions. Taking a ship variable mass floating raft system as the research object, the effect of mass change on the characteristics of raft displacement, isolator load distribution, and modal frequency of the vibration isolation system is analyzed. The analysis shows that when the liquid tank goes from full load to no-load state, its mass change accounts for 40% of the total mass of the raft, which will cause a large displacement of the raft and change the low order modal frequency of the system, bringing the risk of equipment safety and vibration isolation performance degradation. Therefore, an adaptive variable load control method is proposed to realize the raft attitude balance and load equalization optimization under the variable mass condition of the floating raft air spring system. The test results show that the proposed control method can automatically adapt to the large mass gradual change from full load to no load of the liquid tank on the raft, and control the displacement of the raft structure from about 10 mm to 1.5 mm, which effectively ensures the stability of the air spring system performance.

Src family kinases engage differential pathways for encapsulation into extracellular vesicles.

Extracellular vesicles (EVs) are heterogeneous biological nanoparticles secreted by all cell types. Identifying the proteins preferentially encapsulated in secreted EVs will help understand their heterogeneity. Src family kinases including Src and Fyn are a group of tyrosine kinases with fatty acylation modifications and/or multiple lysine residues (contributing charge interaction) at their N-terminus. Here, we demonstrate that Src and Fyn kinases were preferentially encapsulated in EVs and fatty acylation including myristoylation and palmitoylation facilitated their encapsulation. Genetic loss or pharmacological inhibition of myristoylation suppressed Src and/or Fyn kinase levels in EVs. Similarly, loss of palmitoylation reduced Fyn levels in EVs. Additionally, mutation of lysine at sites 5, 7, and 9 of Src kinase also inhibited the encapsulation of myristoylated Src into EVs. Knockdown of TSG101, which is a protein involved in the endosomal sorting complexes required for transport (ESCRT) protein complex mediated EVs biogenesis and led to a reduction of Src levels in EVs. In contrast, filipin III treatment, which disturbed the lipid raft structure, reduced Fyn kinase levels, but not Src kinase levels in EVs. Finally, elevated levels of Src protein were detected in the serum EVs of host mice carrying constitutively active Src-mediated prostate tumors in vivo. Collectively, the data suggest that different EVs biogenesis pathways exist and can regulate the encapsulation of specific proteins into EVs. This study provides an understanding of the EVs heterogeneity created by different EVs biogenesis pathways.

Performance Enhancement by Exploiting Geometrical Nonlinearity of Inerters in a Two-Stage Vibration Isolator

This research proposes a two-stage vibration isolation system (TS-VIS) exploiting geometrical nonlinearity by inerters for performance enhancement. Lateral inerters are added to upper and lower stages creating geometric nonlinearity. The transmissibility and power flow indices are used for the performance evaluation. It is demonstrated that the inerters in both stages of the TS-VIS can enhance substantially the effectiveness of isolation at low frequencies by bending and shifting the resonance peaks in the force and energy transmission curves to the left while reducing the peak heights in these curves. It shows the use of inerters introduces a local minimum in the transmissibility curve which can be exploited for significant reduction in vibration transmission at a desirable frequency. By tailoring the inertance ratios for both stages of the TS-VIS, further improvements on the performance can be achieved by extending the frequency range of effective isolation. This work shows the benefits of using nonlinear inerters in the TS-VIS to obtain superior low-frequency isolation performance, which is potentially applicable in engineering systems such as floating raft structures.

Recently developed glycosphingolipid probes and their dynamic behavior in cell plasma membranes as revealed by single-molecule imaging.

Glycosphingolipids, including gangliosides, are representative lipid raft markers that perform a variety of physiological roles in cell membranes. However, studies aimed at revealing their dynamic behavior in living cells are rare, mostly due to a lack of suitable fluorescent probes. Recently, the ganglio-series, lacto-series, and globo-series glycosphingolipid probes, which mimic the behavior of the parental molecules in terms of partitioning to the raft fraction, were developed by conjugating hydrophilic dyes to the terminal glycans of glycosphingolipids using state-of-art entirely chemical-based synthetic techniques. High-speed, single-molecule observation of these fluorescent probes revealed that gangliosides were scarcely trapped in small domains (100nm in diameter) for more than 5ms in steady-state cells, suggesting that rafts including gangliosides were always moving and very small. Furthermore, dual-color, single-molecule observations clearly showed that homodimers and clusters of GPI-anchored proteins were stabilized by transiently recruiting sphingolipids, including gangliosides, to form homodimer rafts and the cluster rafts, respectively. In this review, we briefly summarize recent studies, the development of a variety of glycosphingolipid probes as well as the identification of the raft structures including gangliosides in living cells by single-molecule imaging.

Investigation on the stability of raft structure in single crystal superalloy

The thermal stability of CMSX-4 nickel-based single crystal superalloy with the raft structure is investigated by analyzing and comparing the macro-oxidation and in-situ oxidation experiments. After the macroscopic oxidation, it could be found that two kinds of oxidation morphologies appeared on the superalloy surface: region A (dendrite stem) and region B (interdendrite). In regions A, the oxidation layer is relatively thick and composed of two oxide layers with the respective main components NiO and Co2O3. The interdendritic region B clustered Mo, Cr, Ti, Ta, Al and other elements has only one very thin oxide layer, the main components are Al2O3, Cr-O and TiO. The oxide layer is relatively dense and can isolate air and prevent further oxidation of the alloy. The further in-situ oxidation experiments of CMSX-4 superalloy showed that the thickness change is due to the migration of elements during the oxidation process, among which Ni element migrates from γ' phase to γ phase, Ta, Ti, Re, Hf, W, Co and Cr migrate from γ phase to γ' phase and the remaining Mo and Al elements did not show obvious migration characteristics. Due to the migration and oxidation of elements, the γ phase becomes thicker and the γ' phase is relatively thinner, thus the stress concentration easily occurs between the two phases, resulting in small voids aggregation, the cracks initiation and the final failure fracture.

In situ studies on the evolution of damage microstructures in tungsten under heavy ion irradiation and post annealing

The evolution of heavy-ion irradiation induced microstructures, followed by annealing experiments, was analyzed in situ and characterized systematically in tungsten via transmission electron microscopy. The formation and evolution of loop rafts, dislocation decoration, and tangled dislocation networks were analyzed during irradiation. Consisting of 1/2<111> loops, raft structures had a preferred orientation, which was dependent on loop geometry. Decoration of a near-edge line dislocation with loops led the line first to curve and then annihilate. Drastic loss of loops, loop-loop coalescence, glide of jogged line dislocations as well as untangling of dislocation networks were observed during post-annealing. The gliding of glissile loops varied with its size, while the motion of line dislocations depended on their nature. The glide distance for the small loops with a size range from 1 to 3 nm was 6 times larger than the large loops with a size range from 5 to 8 nm. A near-edge dislocation had the largest mobility, a near-screw one had the lowest mobility, and a mixed one had the mobility in between. The direct observation and comprehensive analysis of the complicated interaction among dislocations will offer insights into the bridge between the microstructural evolution and macroscopic response to irradiation damages.

Stress-rupture behavior of a Re-containing Ni-base single crystal superalloy at high temperatures

A Re-containing Ni-base single crystal superalloy was used to investigate the elementary processes associated with stress-rupture behavior at different temperatures where the γʹ rafting occurs. At 900 °C, the rupture behavior is mainly determined by the multiplication of dislocations within the widening γ channels, which is closely linked with the propagation of microcracks along the inherent γ/γʹ interfaces. The rapid formation of lamella γ/γʹ raft structure, along with the developed-well interfacial dislocation networks, and its elastic instability are primarily responsible for the rupture behavior at 1100 °C. There is a clear curvature tendency in the Larson-Miller plot of stress-rupture lifetime in relation to stress at high temperatures. It indicates that the influence extent of γʹ rafting on stress-rupture behavior is sensitive to the acting conditions of temperature and stress.

Cardioprotective and anti-inflammatory effects of Caveolin 1 in experimental diabetic cardiomyopathy.

Previous studies of the Caveolin 1 (Cav1) protein and caveolae, which are lipid raft structures found on the plasma membranes of certain cells, are associated with fat metabolism disorders, inflammation, diabetes, and cardiovascular disease. However, there have been no reports linking Cav1 to diabetic cardiomyopathy (DCM). In the present study, we established a relationship between Cav1 and the development of DCM. We found that compared with Cav1+/+ mice, Cav1-/- diabetic mice exhibited more severe cardiac injury, increased activation of NF-κB signaling, and up-regulation of downstream genes, including hypertrophic factors and inflammatory fibrosis factors in heart tissues. Additionally, in vitro results showed that knocking down Cav1 further activated HG-induced NF-κB signaling, increased the expression of downstream target genes, and decreased the expression of inhibitor α of NF-κB (iκBα), all of which have been linked to DCM pathogenesis. In contrast, Cav1 overexpression resulted in the opposite effects. Our study suggests that Cav1 knockdown promotes cardiac injury in DCM by activating the NF-κB signaling pathway, and targeting Cav1 may lead to the development of novel treatments for DCM.

Lipid domain boundary triggers membrane damage and protein folding of human islet amyloid polypeptide in the early pathogenesis of amyloid diseases

The misfolding and self-aggregation of human Islet Amyloid Polypeptide (hIAPP) are linked to the onset of type 2 diabetes (T2D). However, the mechanism of how the disordered hIAPP aggregates trigger membrane damage leading to the loss of Islet cells in T2D is unknown. Using coarse-grained (CG) and all-atom (AA) molecular dynamics simulations, we have investigated the membrane-disruption behaviors of hIAPP oligomers on the phase-separated lipid nanodomains that mimic the highly heterogeneous lipid raft structures of cell membranes. Our results revealed that hIAPP oligomers preferentially bind to the liquid-ordered and liquid-disordered domain boundary around two hydrophobic residues at L16 and I26, and lipid acyl chain order disruption and beta-sheet formation occur upon hIAPP binding to the membrane surface. We propose that the lipid order disruption and surface-induced beta-sheet formation on the lipid domain boundary represent the early molecular events of membrane damage associated with the early pathogenesis of T2D.

The prohibitin complex regulates macrophage fatty acid composition, plasma membrane packing, and lipid raft-mediated inflammatory signaling

Prohibitins (PHB1 and PHB2) are ubiquitously expressed proteins which play critical roles in multiple biological processes, and together form the ring-like PHB complex found in phospholipid-rich cellular compartments including lipid rafts. Recent studies have implicated PHB1 as a mediator of fatty acid transport as well as a membrane scaffold mediating B lymphocyte and mast cell signal transduction. However, the specific role of PHBs in the macrophage have not been characterized, including their role in fatty acid uptake and lipid raft-mediated inflammatory signaling. We hypothesized that the PHB complex regulates macrophage inflammatory signaling through the formation of lipid rafts. To evaluate our hypothesis, RAW 264.7 macrophages were transduced with shRNA against PHB1, PHB2, or scrambled control (Scr), and then stimulated with lipopolysaccharide (LPS) or tumor necrosis factor-alpha (TNF-α), which activate lipid raft-dependent receptor signaling (CD14/TLR4 and TNFR1, respectively). PHB1 knockdown was lethal, whereas PHB2 knockdown (PHB2kd), which also resulted in decreased PHB1 expression, led to attenuated nuclear factor-kappa-B (NF-κB) activation and subsequent cytokine and chemokine production. PHB2kd macrophages also had decreased cell surface TNFR1, CD14, TLR4, and lipid raft marker ganglioside GM1 at baseline and post-stimuli. Post-LPS, PHB2kd macrophages did not increase the concentration of cellular saturated, monounsaturated, and polyunsaturated fatty acids. This was accompanied by decreased lipid raft formation and modified plasma membrane molecular packing, further supporting the PHB complex's importance in lipid raft formation. Taken together, these data suggest a critical role for PHBs in regulating macrophage inflammatory signaling via maintenance of fatty acid composition and lipid raft structure. SummaryProhibitins are proteins found in phospholipid-rich cellular compartments, including lipid rafts, that play important roles in signaling, transcription, and multiple other cell functions. Macrophages are key cells in the innate immune response and the presence of membrane lipid rafts is integral to signal transduction, but the role of prohibitins in macrophage lipid rafts and associated signaling is unknown. To address this question, prohibitin knockdown macrophages were generated and responses to lipopolysaccharide and tumor necrosis factor-alpha, which act through lipid raft-dependent receptors, were analyzed. Prohibitin knockdown macrophages had significantly decreased cytokine and chemokine production, transcription factor activation, receptor expression, lipid raft assembly and membrane packing, and altered fatty acid remodeling. These data indicate a novel role for prohibitins in macrophage inflammatory signaling through regulation of fatty acid composition and lipid raft formation.

Vibration analysis of functionally graded material (FGM) double layered floating raft structure by the spectro-geometric method

This paper aims to analyze the vibration characteristics of functionally graded material (FGM) double layered floating raft structures under various boundary conditions. The artificial virtual spring technique is introduced to simulate the boundary conditions and coupling effect between the FGM plates by adjusting the spring stiffness. The spectro-geometric method is used to describe the displacement admissible function, which overcomes the discontinuity or jump phenomenon at the boundary for the conventional Fourier series. Based on the unified Rayleigh-Ritz energy framework, the dynamic equations of the FGM double layered floating raft structure are derived, and the corresponding vibration characteristics are obtained. The correctness of the presented method is verified by some numerical examples of comparisons with the calculation results obtained from the finite element method. After that, parametric analysis is carried out to investigate the effects of material parameters, geometric parameters, coupling spring stiffness, and coupling damping on the steady-state response of the FGM double layered floating raft with various boundary conditions.

Application research of acoustic black hole in floating raft vibration isolation system

AbstractAcoustic black holes have good application prospects in the field of vibration and noise reduction. Based on engineering practice, this study proposes a systematic process method for the application of acoustic black hole structure in raft structure, which provides new ideas and references for improving the vibration isolation performance of floating raft system and reducing the level of ship vibration and noise. The influence law of each parameter on structural vibration and the recommended value range of each parameter are given, which provides support for the systematic method and process of the application of acoustic black holes in the raft structure. Then, the acoustic black hole process is applied to a floating raft system. According to the characteristics of the raft structure, an application scheme of the acoustic black hole in the raft structure is formed, and the vibration level drop of the floating raft vibration isolation system before and after the acoustic black hole is embedded, calculated, and analyzed. The changes further improve the vibration reduction and isolation performance of the raft system and effectively reduced the mechanical noise level of the ship’s cabin.

Experimental Study on Vibration Velocity of Piled Raft Supported Embankment and Foundation for Ballastless High Speed Railway

In recent years, the high development of high-speed railway lines cross through areas with poor geological conditions, such as soft soil, offshore and low-lying marsh areas, resulting geotechnical problems, such as large settlements and reduction of bearing capacity. As a new soil reinforcement method in high speed railway lines, the piled raft structure has been used to improve soil conditions and control excess settlement. In order to study the dynamic behavior of piled raft supported ballastless track system in soft soil, an experimental study on vibration velocities of piled raft supported embankment and foundations is presented in soft soil with different underground water levels. Vibration velocities at specified positions of the piled raft supported embankment and foundations are obtained and discussed. The vibration velocity curves on various testing locations of piled raft foundations are clearly visible and have sharp impulse and relaxation pattern, corresponding to loading from train wheels, bogies, and passages. Vibration velocity distribution in the horizontal direction at three train speeds clearly follows an exponential curves. Most of the power spectrums of vibration velocity at various locations are mainly concentrated at harmonic frequencies. The change in water level has slight impaction on the peak spectrum of vibration velocity at harmonic frequencies. The vibration power induced by train loads are transmitted, absorbed, and weakened to a certain extent through embankment and piled raft structure. The dynamic response character of embankments are affected by their self-vibration characteristics and the dynamic bearing capacity of the piled raft structure.

The Roles of CD44 Membrane Ruffling and Signaling in Leukocyte Transmigration across Cryptococcus Neoformans-Coinfected Blood-Brain Barrier with HIV-1 gp41 in Vitro

Cryptococcus neoformans (Cn) is a critical human pathogen, mainly causes Cryptococcal meningitis with severe symptoms and high mortality. As an environmental yeast, Cn initiates infection after inhalation and spreads hematogenously to almost all organs. To cause Cryptococcal meningitis, Cn must invade the blood-brain barrier (BBB) that consists of brain microvascular endothelial cells (BMEC) and adhere to the host cell to resist the blood-flow. Previous studies have demonstrated that CD44, a cell adhesion molecule that mediates cell-cell and cell-matrix interactions, is involved in the invasion of Cn into human non-small cell lung cancer cells, providing a fundamental insight into the mechanism of Cn penetrating the blood-air barrier. Moreover, the binding between Cn and BMEC is enhanced by HIV-1 gp41 ectodomain (gp41-I90), which is related to its enhanced role in Cn-induced cytoskeletal changes. Both gp41-I90 and Cn are able to promote the CD44-mediated monocyte transmigration separately, and co-exposure to both would further accelerate the transmigration. The Cn CPS1 gene encodes a hyaluronic acid synthase, a product of which hyaluronic acid is the main receptor for CD44 in vivo. In addition, CD44 functions as the primary receptor during Cn infection. Although the mechanism how Cn crosses the BBB and causes CNS infection keeps mysterious, we suggest that CD44 plays a vital role in the interaction among Cn, leukocyte and BMEC. To investigate the effect of CD44 in Cn infection into BMEC, we explored several cellular and molecular events during Cn invasion. Results showed that CD44 molecules from lipid rafts can interact with hyaluronic acid. The adherence and invasion of Cn were abrogated while CD44 was perturbed by Bikunin, a protein which can disturb the oligomerization of CD44 on membrane lipid rafts. The lipid raft marker, ganglioside GM1, co-localizes with CD44 on the plasma membrane, allowing Cn cells to adhere to host cells in GM1-enriched sites, illustrating that CD44 anchors on the lipid rafts and serves as the host receptor for Cn. Upon Cn engagement, GM1 internalized through vesicular structures to the nuclear membrane. This endocytic redistribution process is abolished by cytochalasin D, nocodazole, or anti-DYRK3 siRNA. The knockdown of DYRK3 significantly reduces Cn invasion across the BMEC. Cav1, a characteristic protein of caveolae/lipid rafts, colocalized with CD44 in certain regions on the plasma membrane (10~15%). The knockdown of Cav1 significantly reduced Cn invasion and the crossing of the BMEC. Upon Cn engagement, Cav1 was phosphorylated in a CD44-dependent manner, which was diminished by filipin, a disrupter of lipid raft structure. These findings imply that CD44 anchors on lipid rafts and plays a vital role in Cn infection and the perturbation of CD44, Cav-1 or DYRK3 would block Cn adherence and invasion to BMEC. Furthermore, CD44 has an effect on leukocyte migration mediated by Cn. Cn infection into BMEC significantly enhanced the adhesion and migration of THP-1 cell (human leukemic monocytes) across the monolayers (P < 0.01), depending on the concentration and exposure time of Cn (P < 0.05). The addition of anti-CD44 and Bikunin to BMEC after Cn infection showed both adhesion and migration of THP-1 were significantly decreased (P < 0.01) in a dose dependent manner of the antibody (within 0-1 μg) and inhibitor (within 0-20 nmol/L). Both THP-1 adhesion and migration decreased in the BBB model infected with CPS1 gene-knockout Cn strain (P < 0.01, P < 0.05), but increased in complemented strain and wild-type strain. What's more, we also elaborated that gp41-I90 has an effect of enhancement in monocyte transmigration across Cn-infected BMEC, which may be induced by CD44. In conclusion, both CD44 and gp41-I90 play a vital role in THP-1 adhering to Cn-stimulated BMEC and migrating across BBB. In summary, we indicate the CD44 molecule plays a crucial role in leukocyte transmigration. CD44 functions in conjunction with DYRK3, Cav1 and gp41-I90 on lipid rafts. Anti-CD44 and Bikunin, especially the latter, can significantly reduce leukocytes migration, and have certain application prospects in reducing inflammatory responses. The specific mechanism, however, is beneath the surface and studies is urgently appreciated. (Acknowledgements: Corresponding author: Hong Cao, gzhcao@smu.edu.cn; Grant from School of Public Health of Southern Medical University, China, No. GW202222 to H.C.)

High-Temperature Creep Behavior of a Nickel-Based Single-Crystal Superalloy with Small-Angle Deviation from [111] Orientation

By means of tensile creep tests and microstructure analysis, the creep behavior and deformation mechanism of a nickel-based single-crystal alloy with small-angle deviations from the [111] orientation at 1040°C/137 MPa were investigated. The results suggested that in the early stage of creep, proliferating dislocations generated by different slip systems get accumulated in the γ phase. Dislocations mainly slipped in the γ phase and climbed over the γ′ phase, and they began to form a dislocation network at the interface. γ′ phases were connected to each other, and the coherence relationship was destroyed. In the steady-state stage of creep, the solid interfacial dislocation network was formed, and the γ′ phase transformed into a lamellar raft structure, which hinders the slip and climb of dislocations in the matrix channel. In the accelerated creep stage, the dislocation network was destroyed, and dislocations sheared into the γ′ phase in the way of dislocation pairs, which could react to form a superdislocation node and decompose to form APBs on the &lt;111&gt; plane or cross slip from the &lt;111&gt; plane to the &lt;100&gt; plane to form K-W locks.

The Formation and Disintegration of Rafts from Different Aluminas and Fines

Raft formation is a frequently encountered problem during alumina feeding in the Hall-Héroult-process and will delay alumina from being dissolved into the melt. The mechanisms for the formation and disintegration of rafts are however not thoroughly understood yet. The current study investigates the dissolution behavior and raft structure from three different types of secondary alumina in a lab cell, with a particular attention to effect of fines, and involves both sampling of rafts and video recordings of the feeding. The mass loss rate was calculated to vary between −1.57 and −0.42 g min−1 for regular bulk alumina, and −1.15 and −0.06 g min−1 for fines. Rafts created from bulk alumina were flat with a distinct bulge or crater placed in the center of it, while rafts created from fines had a pellet-shaped structure and traces of undissolved alumina in the middle. The observed structure is due to the initial spreading of powder, confirmed by video recordings.

Inhibitory and Injury-Protection Effects of O-Glycan on Gastric Epithelial Cells Infected with Helicobacter pylori.

ABSTRACTHelicobacter pylori (H. pylori) is an important pathogen that can cause gastric cancer. Multiple adhesion molecules mediated H. pylori adherence to cells is the initial step in the infection of host cells. H. pylori cholesterol-α-glucosyltransferase (CGT) recognizes and extracts cholesterol from cell membranes to destroy lipid raft structure, further promotes H. pylori adhesion to gastric epithelial cells. O-Glycan, a substance secreted by the deep gastric mucosa, can competitively inhibit CGT activity and may serve as an important factor to prevent H. pylori colonization in the deep gastric mucosa. However, the inhibitory and injury-protection effects of O-Glycan against H. pylori infection has not been well investigated. In this study, we found that O-Glycan significantly inhibited the relative urease content in the coinfection system. In the presence of O-glycan, the injury of GES-1 cells in H. pylori persistent infection model was attenuated and the cell viability was increased. We use fluorescein isothiocyanate-conjugated cholera toxin subunit B (FITC-CTX-B) to detect lipid rafts on gastric epithelial cells and observed that O-glycan can protect H. pylori from damaging lipid raft structures on cell membranes. In addition, transcriptome data showed that O-glycan treatment significantly reduced the activation of inflammatory cancer transformation pathway caused by H. pylori infection. Our results suggest that O-Glycan is able to inhibit H. pylori persistent infection of gastric epithelial cells, reduce the damage caused by H. pylori, and could serve as a potential medicine to treat patients infected with H. pylori.

Ni基単結晶超合金のラフト組織

Ni基単結晶超合金のラフト組織

Dynamic characteristic analysis of acoustic black hole in typical raft structure

Abstract As a hot content of research in recent years, acoustic black holes have bright application prospects in the field of vibration and noise reduction. In this article, based on the acoustic black hole theory, we carry out a study on the dynamic characteristics of a typical raft structure. The manuscript gives the simplified method of the acoustic black hole model, verifies the validity of the method by the structure natural frequency and vibration response, and discusses the influence of the main parameters such as acoustic black hole tip cutoff ratio and damping thickness ratio on the vibration characteristics of the raft frame structure. The better values of the parameters were applied to the raft structure on this basis, and the results showed that the peak value of some frequency points decreased by about 10 dB after the acoustic black hole was laid in the raft structure, which improved the vibration isolation performance of the raft.

Arachidonic acid, a clinically adverse mediator in the ovarian cancer microenvironment, impairs JAK‐STAT signaling in macrophages by perturbing lipid raft structures

Survival of ovarian carcinoma is associated with the abundance of immunosuppressed CD163highCD206high tumor‐associated macrophages (TAMs) and high levels of arachidonic acid (AA) in the tumor microenvironment. Here, we show that both associations are functionally linked. Transcriptional profiling revealed that high CD163 and CD206/MRC1 expression in TAMs is strongly associated with an inhibition of cytokine‐triggered signaling, mirrored by an impaired transcriptional response to interferons and IL‐6 in monocyte‐derived macrophages by AA. This inhibition of pro‐inflammatory signaling is caused by dysfunctions of the cognate receptors, indicated by the inhibition of JAK1, JAK2, STAT1, and STAT3 phosphorylation, and by the displacement of the interferon receptor IFNAR1, STAT1 and other immune‐regulatory proteins from lipid rafts. AA exposure led to a dramatic accumulation of free AA in lipid rafts, which appears to be mechanistically crucial, as the inhibition of its incorporation into phospholipids did not affect the AA‐mediated interference with STAT1 phosphorylation. Inhibition of interferon‐triggered STAT1 phosphorylation by AA was reversed by water‐soluble cholesterol, known to prevent the perturbation of lipid raft structure by AA. These findings suggest that the pharmacologic restoration of lipid raft functions in TAMs may contribute to the development new therapeutic approaches.