Polarization Changes Research Articles

MeerKAT observations of pair-plasma induced birefringence in the double pulsar eclipses

ABSTRACT PSR J0737−3039A/B is unique among double neutron star systems. Its near-perfect edge-on orbit causes the fast spinning pulsar A to be eclipsed by the magnetic field of the slow spinning pulsar B. Using high-sensitivity MeerKAT radio observations combined with updated constraints on the system geometry, we studied the impact of these eclipses on the incident polarization properties of pulsar A. Averaging light curves together after correcting for the rotation of pulsar B revealed enormous amounts of circular polarization and rapid changes in the linear polarization position angle, which occur at phases where emission from pulsar A is partially transmitted through the magnetosphere of pulsar B. These behaviours confirm that the eclipse mechanism is the result of synchrotron absorption in a relativistic pair-plasma confined to the closed-field region of pulsar B’s truncated dipolar magnetic field. We demonstrate that changes in circular polarization handedness throughout the eclipses are directly tied to the average line of sight magnetic field direction of pulsar B, from which we unambiguously determine the complete magnetic and viewing geometry of the pulsar.

Explore the expression of mitochondria-related genes to construct prognostic risk model for ovarian cancer and validate it, so as to provide optimized treatment for ovarian cancer.

The use of gene development data from public database has become a new starting point to explore mitochondrial related gene expression and construct a prognostic prediction model of ovarian cancer. Data were obtained from the TCGA and ICGC databases, and the intersection with mitochondrial genes was used to obtain the differentially expressed genes. q-PCR, Cox proportional risk regression, minimal absolute contraction and selection operator regression analysis were performed to construct the prognostic risk model, and ROC curve was used to evaluate the model for centralized verification. The association between risk scores and clinical features, tumor mutation load, immune cell infiltration, macrophage activation analysis, immunotherapy, and chemosensitivity was further evaluated. A prognostic risk score model for ovarian cancer patients was constructed based on 12 differentially expressed genes. The score was highly correlated with ovarian cancer macrophage infiltration and was a good predictor of the response to immunotherapy. M1 and M2 macrophages in the ovarian tissue in the OV group were significantly activated, providing a reference for the study of the polarity change of tumor-related macrophages for the prognosis and treatment of ovarian cancer. In terms of drug sensitivity, the high-risk group was more sensitive to vinblastine, Acetalax, VX-11e, and PD-0325901, while the low-risk group was more sensitive to Sabutoclax, SB-505124, cisplatin, and erlotinib. The prognostic risk model of ovarian cancer associated to mitochondrial genes built on the basis of public database better evaluated the prognosis of ovarian cancer patients and guided individual treatment.

Novel dual-color fluorescence probe for monitoring the fluctuation of lysosomal polarity and viscosity during apoptosis

Apoptosis is pivotal in the pathogenesis of cancer and various other diseases. Real-time monitoring of apoptosis is crucial for assessing cell viability and facilitating drug screening. The process of apoptosis tends to cause changes in cellular microenvironmental factors. The variations of the microenvironment can serve as an indicator of the degree of apoptosis. Thus, the development of a smart and facile probe responding to cellular microenvironmental factors is significant for visualizing the apoptotic process. In this research, we designed a novel dual-color fluorescent probe, Lyso-DCPV, which incorporates N, N-diethyl coumarin as its polarity-responsive module, and the twisting double bond between N, N-diethyl coumarin and N-propyl quinoline as its viscosity-responsive module. The green fluorescence of Lyso-DCPV is sensitive to polarity changes, diminishing as polarity increases. Conversely, the red fluorescence intensifies with escalating viscosity. The probe specifically targets lysosomes, producing green fluorescence in live cells. Due to Lyso-DCPV’s acute sensitivity to changes in polarity and viscosity, it is well-suited to observe variations in the intracellular lysosomal microenvironment during drug-induced apoptosis. We also employed Lyso-DCPV for the dynamic assessment of polarity and viscosity during peroxide-induced apoptosis, enabling the observation of cell viability through variations in the probe’s emission color and intensity. The distinct probe will pave the way for novel strategies in evaluating apoptosis-related drugs. Moreover, Lyso-DCPV stands as an exemplary molecular instrument to elucidate the interplay between polarity and viscosity, facilitating the exploration of the interrelation in the cellular microenvironment during apoptosis.

Endless optical domain polarization demultiplexing in 2000 km simplified coherent transceiver for long-distance transmission

We demonstrate an endless optical domain polarization demultiplexing scheme that was realized in a 96 Gbaud-PS-16QAM coherent transmission system to alleviate the data processing pressure of the DSP in the receiver. It can be effectively employed in the 140 km fiber link (Metro DCI) and extended to the 2000 km optical fiber networks (Long haul DCI or backbone networks transmission). It can track 10 krad/s state of polarization (SOP) changes following Rayleigh distribution which is the general statistical case for real fibers. The proposed method has a noise tolerance equivalent to that induced by a 2000 km transmission, with OSNR as low as 20 dB, with a maximum PMD of 4 ps and a mean DGD of 2.5 ps.

Role of Intermolecular Interactions in Deep Eutectic Solvents for CO2 Capture: Vibrational Spectroscopy and Quantum Chemical Studies.

Recent research and reviews on CO2 capture methods, along with advancements in industry, have highlighted high costs and energy-intensive nature as the primary limitations of conventional direct air capture and storage (DACS) methods. In response to these challenges, deep eutectic solvents (DESs) have emerged as promising absorbents due to their scalability, selectivity, and lower environmental impact compared to other absorbents. However, the molecular origins of their enhanced thermal stability and selectivity for DAC applications have not been explored before. Therefore, the current study focuses on a comprehensive investigation into the molecular interactions within an alkaline DES composed of potassium hydroxide (KOH) and ethylene glycol (EG). Combining Fourier transform infrared (FT-IR) and quantum chemical calculations, the study reports structural changes and intermolecular interactions induced in EG upon addition of KOH and its implications on CO2 capture. Experimental and computational spectroscopic studies confirm the presence of noncovalent interactions (hydrogen bonds) within both EG and the KOH-EG system and point to the aggregation of ions at higher KOH concentrations. Additionally, molecular electrostatic potential (MESP) surface analysis, natural bond orbital (NBO) analysis, quantum theory of atoms-in-molecules (QTAIM) analysis, and reduced density gradient-noncovalent interaction (RDG-NCI) plot analysis elucidate changes in polarizability, charge distribution, hydrogen bond types, noncovalent interactions, and interaction strengths, respectively. Evaluation of explicit and hybrid models assesses their effectiveness in representing intermolecular interactions. This research enhances our understanding of molecular interactions in the KOH-EG system, which are essential for both the absorption and desorption of CO2. The study also aids in predicting and selecting DES components, optimizing their ratios with salts, and fine-tuning the properties of similar solvents and salts for enhanced CO2 capture efficiency.

Experimental demonstration on the proactive detection of fiber tapping in optical chaos communication.

Optical chaos communication has a physical-layer security advantage but defends passively against a malicious attack. Here, we conduct a proof-of-concept experiment of detecting the attack proactively by observing performance degradation in optical chaos communication tapped with fiber bending. Influences of the curvature radius of the bent fiber on a chaos synchronization coefficient and bit error rate are investigated. Results show that the synchronization coefficient decreases from 0.958 to 0.904 and the bit error rate increases from 1.31 × 10-4 to 1.73 × 10-3 under a curvature radius of 10 mm, revealing the attack. Bending fiber to this extent leads to a power loss of 1.81%, which is difficult to detect by the optical time-domain reflectometer but causes significant interference to chaos communication due to the concurrent change in the light polarization, jointly decreasing the effective optical injection strength for yielding chaos synchronization.

Giant magneto-optical Kerr effects governed by the quasi-bound states in the continuum

The magneto-optical Kerr effect (MOKE), as one of the magneto-optical effects, exhibits polarization change upon reflection that can be used to explore the internal information of magnetic materials with broad applications in modern information technology. However, typically, MOKE is quite weak due to the lower magneto-optical interaction. To tremendously enhance the MOKE, quasi-bound states in the continuum in a one-dimensional Ce- doped Y3Fe5O12 (CeYIG) film photonic crystal slabs (PCS) are proposed to improve the magneto-optical interaction in this work. A giant enhancement in the rotation angle and ellipticity of the longitudinal MOKE, which is about 93.4 and 136.8 times stronger than a pure uniform CeYIG, can be realized. Almost circularly polarized reflected beams with different chiralities are obtained with the CeYIG film. By tuning the geometric parameters of the PCS and the applied external magnetic field, dynamic control of polarization states of the reflected beams with different wavelengths can be realized. This magneto-optical metasurface provides a convenient way for the implementation of magneto-optical devices such as information memory devices, sensors, polarizers, and chiral devices.

Toward Strong UV-Vis-NIR Second-Harmonic Generation by Dimensionality Engineering of Zinc Thiocyanates.

The precise modulation of the spatial orientations and connection modes of primitives is vital for certain critically important optical functions for nonlinear optical (NLO) materials (specifically, second-harmonic generation (SHG) and optical bandgap); however, we are yet to achieve a sufficient level of control for the designed construction of efficient broadband NLO materials. Exploiting the changes in microscopic polarization that may result from dimensional increase, we propose herein a zero-dimensional (0D)-to-three-dimensional (3D) dimensionality-increase strategy to realize strong broadband SHG responses for the first time. The novel 3D pseudo diamond-like Zn(SCN)2 has been synthesized by removing SHG-inactive [NH4]+ counter cations and H2O molecules that are located between the adjacent discrete [Zn(SCN)4] building blocks within the 0D (NH4)2Zn(SCN)4·3H2O. The 0D-to-3D dimensionality engineering, proceeding from (NH4)2Zn(SCN)4·3H2O to Zn(SCN)2, results in significantly enhanced SHG responses and efficient broadband activity (8 × KH2PO4 @ 1064 nm, 4.18 eV bandgap for the former c.f. 2 × β-BaB2O4 @ 380 nm, 30 × KH2PO4 @ 1064 nm, 2 × KTiOPO4 @ 2100 nm, 4.78 eV bandgap for the latter) from the UV to the NIR regions (SHG@300-1050 nm). Theoretical calculations and crystal structure analyses reveal that the coordination-bond-connected [Zn(SCN)4] building blocks within the diamond-like structure of Zn(SCN)2 are responsible for its giant broadband SHG responses.

Modification of an AIE Fluorescent Probe for Monitoring the Polarity of Lipid Droplets Based on a Series of Synthesized Aryl Naphthalizes.

Lipid droplets (LDs) are subcellular organelles that are dynamic and play a central role in energy homeostasis and lipid metabolism. They also contribute to the transport and maturation of cellular proteins and are closely associated with several diseases. The important role of the cellular microenvironment in maintaining cellular homeostasis. Changes in cell polarity, particularly in organelles, have been found to be strongly linked to inflammation, Alzheimer's disease, cancer, and other illnesses. It is essential to check the polarity of the LDs. A series of arylated naphthalimide derivatives were synthesized using the Suzuki reaction. Modification of synthesized aryl naphthalimides using oligomeric PEG based on intramolecular charge transfer (ICT) mechanism. A series of fluorescent probes were designed to target LDs and detect their polarity. Nap-TPA-PEG3 probe exhibited high sensitivity to polarity. The addition of oligomeric polyethylene glycol (PEG) to the probe not only significantly improved its solubility in water, but also effectively reduced its cytotoxicity. In addition, the probe exhibited excellent aggregation-induced luminescence (AIE) properties and solvent discolouration effects. Nap-TPA-PEG3 probe exhibited high Pearson correlation coefficient (0.957163) in lipid droplet co-localization in cells. Nap-TPA-PEG3 could be used as an effective hand tool to monitor cell polarity.

Electron Spin Polarization in the Triplet State of Methoxy-substituted Phosphorus(V) Tetraphenyl Porphyrins

Photoexcited triplet states of porphyrins are of great relevance in various applications due to their high yield, long lifetime, and strong electron spin polarization. This study delves into properties and spin dynamics of the triplet state of a series of hypervalent phosphorus(V) porphyrins. Transient Electron Paramagnetic Resonance (TrEPR) measurements, supported by quantum chemical calculations as well as by optical absorption/luminescence experiments, reveal that, unlike singlet states, the lowest triplet state does not exhibit charge-transfer (CT) character upon photoexcitation. However, the presence of excited CT singlet states alters the intersystem crossing in phosphorus(V) porphyrins, leading to a sign change in the initial multiplet polarization of the photoexcited triplet state. TrEPR results further demonstrate that significant net polarization develops in the triplet states of the phosphorus(V) porphyrins due to the dynamic Jahn-Teller effect. Yet, this effect remains largely unaffected by differences in their molecular structures.

Dynamic changes in macrophage polarization during the resolution phase of periodontal disease.

Polarization of macrophages (Mφ) is a well-controlled axis with considerable consequences in both the pro-inflammatory and resolution phases of inflammation. We aimed to determine if periodontal therapy may instigate M1 to M2 Mφ polarization favoring resolution of inflammation within periodontal tissues. Gingival biopsies were excised from subjects diagnosed with Stage III, Grade B periodontitis before and 4-6 weeks after nonsurgical periodontal therapy. Total RNA was isolated and pro- and anti-inflammatory markers associated with Mφ polarization assessed by RT-qPCR. Mice were subject to ligature-induced periodontitis and gingival tissues collected after 8 days in-situ or 10 days after ligature removal and M1 and M2 Mφ markers examined by RT-qPCR and flow cytometry. In human samples, improvement in clinical parameters posttherapy correlates with reduced bacterial burden, downregulation in M1 (TNF-α, STAT1, CXCL10, and miR-155), and elevated levels of M2 (STAT6, TGM2, CCL22, and IL-10) Mφ markers. In a murine model of resolution of LIP, we observed reduced levels of M1 Mφ markers cox2, iNOS2, F4/80+CD80+, and F4/80+CD86+ and elevated levels of M2-like Mφ markers tgm2, arg1, F4/80+CD206+ and F4/80+CD163+ corroborated human findings. Resolution of periodontal inflammation is associated with M1 to M2 Mφ polarization after nonsurgical periodontal therapy. Assessment of Mφ markers can provide relevant clinical information on the successful response of periodontal therapy and may be used to target nonresponders.

Large-scale Structure of the Heliospheric Current Sheets within the Heliosheath Inferred from Voyager 2 Observations

In this paper, we conducted an analysis of the heliospheric current sheets (HCSs) in the heliosheath (HS), utilizing observations by Voyager 2 between 2008 and 2018. Employing rigorous criteria, we identified a total of 34 HCSs that indicate significant changes in magnetic polarity. These occurrences were more prevalent during solar maximum periods when the HCS expanded to higher latitudes, coinciding with the spacecraft positioned at an average latitude of −31° from the solar equator. We determined certain features of the large-scale structures of the identified HCSs. Most importantly, employing two distinct methods indicates that the thickness of the HCSs within the HS ranges from ∼0.003 to ∼0.4 au with an average thickness of ∼0.03 to ∼0.1 au, depending on methods of event selection and fitting techniques. This thickness surpasses that known near 1 au or other heliospheric distances. It is also notably thicker than the typical proton inertial length, implying unfavorable conditions for magnetic reconnection. Additionally, our analysis reveals a frequent tilt of HCS planes relative to the solar equatorial plane by a varying angle up to several tens of degrees, likely implying a common occurrence of a warped structure of the HCS within the HS. Longitudinally, the HCS planes closely align with the Parker spiral field direction expected in the HS. Finally, for a large fraction of the identified HCS events, the HCS planes are likely characterized by a rotational discontinuity. These findings are valid within the limits of the 1 hr resolution data used in this study.

Porphyromonas gingivalis Induces Chronic Kidney Disease through Crosstalk between the NF-κB/NLRP3 Pathway and Ferroptosis in GMCs.

Porphyromonas gingivalis (P.gingivalis) is a gram-negative bacterium found in the human oral cavity and is a recognized pathogenic bacterium associated with chronic periodontitis and systemic diseases, including chronic kidney disease (CKD), but the roles and molecular mechanism of P.gingivalis in CKD pathogenesis are unclear. In this study, an animal model of oral P.gingivalis administration and glomerular mesangial cells (GMCs) cocultured with M1-polarized macrophages and P.gingivalis supernatant were constructed. After seven weeks of P.gingivalis gavaged, peripheral blood was collected to detect the changes in renal function. By collecting the teeth and kidneys of mice, H&E staining and IHC were used to analyze the expression of periodontal inflammatory factors in mice, PAS staining was used to analyze glomerular lesions. The supernatant of macrophages was treated with 5% P.gingivalis supernatant. H&E staining, IHC, Western blot and RT-PCR were applied to analyze renal inflammatory factors, macrophage M1 polarization, NF-κB, NLRP3 and ferroptosis changes in vitro. We found that oral P.gingivalis administration induced CKD in mice. P.gingivalis supernatant induced macrophage polarization and inflammatory factor upregulation, which triggered the activation of the NF-κB/NLRP3 pathway and ferroptosis in GMCs. By inhibiting the NF-κB/NLRP3 pathway and ferroptosis in GMCs, cell viability and the inflammatory response were partially alleviated in vitro. We demonstrated that P.gingivalis induced CKD in mice by triggering crosstalk between the NF κB/NLRP3 pathway and ferroptosis in GMCs. Overall, our study suggested that periodontitis can promote the pathogenesis of CKD in mice, which provides evidence of the importance of periodontitis therapy in the prevention and treatment of CKD. P.gingivalis promotes ferroptosis in kidneys and accelerates the progression of CKD through NF-κB/NLRP3 signaling pathway.

Fluorescence lifetime imaging: A novel approach to simultaneous visualizing lipid droplets and endoplasmic reticulum polarity in live cells and fatty liver

Cellular polarity plays an indispensable role in both physiological functions and the progression of diseases, with organelles demonstrating specific polarities that are integral to their roles. The advent of a single fluorescent probe capable of concurrently and selectively visualizing two distinct organelles through distinct fluorescence emission spectra has emerged as a powerful approach for investigating their interactions within cellular mechanisms. However, the use of changes in dual fluorescence lifetimes to monitor polarity changes in two organelles has rarely been employed, despite its potential benefits for more accurate detection of subtle changes in organelle polarity. Herein, two polarity-sensitive probes (ER-LDs-1 and ER-LDs-2) were developed. ER-LDs-2 exhibited high sensitivity to polarity alterations in both lipid droplets (LDs) and endoplasmic reticulum (ER) under various physiological and pathological conditions, including ferroptosis and endoplasmic reticulum stress, as demonstrated by distinct changes in fluorescence lifetime. ER-LDs-2 enables the monitoring of polarity changes in mouse and human normal and fatty liver tissues by fluorescence lifetime imaging. Collectively, this study presents innovative tools that hold great potential for advancing our understanding of cellular organelle polarity dynamics and the progression of associated diseases.

Membrane-Targeting Amphiphilic Honokiol Derivatives Containing an Oxazole Moiety as Potential Antibacterials against Methicillin-Resistant Staphylococcus aureus.

Infections with methicillin-resistant Staphylococcus aureus (MRSA) are becoming increasingly serious, making the development of novel antimicrobials urgent. Here, we synthesized some amphiphilic honokiol derivatives bearing an oxazole moiety and investigated their antibacterial and hemolytic activities. Bioactivity evaluation showed that E17 possessed significant in vitro antibacterial activity against S. aureus and MRSA, along with low hemolytic activity. Moreover, E17 exhibited rapid bactericidal properties and was not susceptible to resistance. Mechanistic studies indicated that E17 interacts with phosphatidylglycerol and cardiolipin of bacterial cell membranes, leading to changes in cell membrane permeability and polarization, increased intracellular ROS, and leakage of DNA and proteins, thus accelerating bacterial death. Transcriptome analysis further demonstrated that E17 has membrane-targeting effects, affecting the expression of genes related to cell membranes and ABC transporter proteins. Notably, in vivo activity showed that E17 has prominent anti-MRSA efficacy, comparable to vancomycin, and is expected to be a new anti-MRSA drug candidate.

Synthesis of a new quaternary ammonium salt for efficient inhibition of mild steel corrosion in 15 % HCl: Experimental and theoretical studies

The corrosion phenomenon and its economic impacts can hardly be ignored in any application. This study synthesized a quaternary ammonium salt (3) containing hydrophobic dodecyl and electron-rich diallylbenzyl amine moieties to be used in 15 % HCl as a corrosion inhibitor of mild steel. Several techniques, such as 1H and 13C NMR, IR, TGA, and elemental analysis, have been used to characterize inhibitor 3. Popular corrosion measurement techniques, namely weight loss, potentiodynamic polarization techniques, and electrochemical impedance spectroscopy, have been used to determine the efficiency of inhibitor 3. At 303 K and a moderately low concentration of 50 ppm, the quaternary ammonium salt-based inhibitor demonstrated a maximum efficiency of ≈95.0 %. At elevated temperatures of 313, 323, and 333 K, the inhibition efficacy values were recorded as 91.3, 82.8, and 75.0 %, respectively. Adsorption isotherm study revealed that the adsorption of inhibitor 3 followed Langmuir adsorption isotherm. The value of ΔGads° was found to be – 40.19 kJ mol−1, indicating that inhibitor 3 became adsorbed via a mixed physi-chemisorption mechanism. A very high adsorption constant (Kads) of 1.53 × 105 L mol−1 suggested strong adsorption of inhibitor 3. The difference in activation energy (Ea) value of 42.4 kJ mol−1 between the control and the inhibited solution indicated an efficient adsorption of inhibitor 3. The ability of inhibitor 3 to retard both anodic and cathodic half-cell reactions was proved via open circuit potential and Tafel curves studies. Detailed discussions on the change in corrosion current densities (icorr), polarization (Rp) and charge transfer (Rct) resistances have been offered to discuss the inhibition efficiency. Water contact angle measurement showed a drastic increase in mild steel surface hydrophobicity following inhibitor 3 adsorption. SEM-EDX and XPS studies confirmed the definitive presence of inhibitor 3 on the mild steel surface. Density functional theory (DFT) studies revealed the frontier molecular orbitals with which the metal surface interacts. A detailed corrosion inhibition mechanism has been offered in the context of adsorption isotherm and DFT studies.

Optimal Blind Focusing on Perturbation‐Inducing Targets in Sub‐Unitary Complex Media

AbstractThe scattering of waves in a complex medium is perturbed by polarizability changes or displacements of embedded targets. These perturbations can serve as perfectly non‐invasive guidestars for focusing on the targets. Here, a fundamental but to‐date overlooked difference between these two perturbation types is theoretically derived: the change of the scattering matrix is of rank one [two] for a polarizability change [displacement] of a point‐like target; optimal strategies to perfectly focus on the target in both cases are identified accordingly. In particular, in the latter case, optimal focusing requires at least two target displacements. Furthermore, for the case of dynamic complex media additionally featuring parasitic perturbers, a non‐invasive scheme to achieve optimal time‐averaged power delivery to a perturbation‐inducing target is established. In all cases, no assumptions about the unitarity of the system's scattering matrix or the perturbation strength are necessary. All results are experimentally demonstrated in the microwave regime using a strongly sub‐unitary lossy chaotic cavity as a complex medium. The experiments highlight that the target's “structural scattering” is irrelevant [must be negligible] in the case of target polarizability changes [displacements]. The presented results are expected to find applications in communications, cybersecurity, wireless bioelectronics, flow‐cytometry, and self‐propelled nano‐swimmers.

Surfactant Regulated Chemical Modification of Rice Straw Powder for Biomass Composite Polyurethane Synthetic Leather

AbstractFor agricultural countries in Aisa, rice straw is a waste product, but also a valuable bioresource, with its recycling methods often drawing widespread attention. In this study, a novel multicomponent extraction method was proposed to perform comprehensive extraction of holocellulose and lignin from rice straw powder (RSP), resulting in modified rice straw powder (MRSP) with different micro‐morphologyies. The results indicate that the cosolvent tetraethylammonium chloride (TEAC) is more effective for extracting holocellulose and lignin compared to others, and different surfactants have decisive impacts on the extraction of holocellulose and lignin from RSP. Among them, anionic surfactants aid in the extraction of holocellulose, with sodium allylate sulfonate (SAS) being superior due to its greater changes in allyl polarity. Conversely, cationic surfactants facilitate the extraction of lignin, with octadearyl trimethyl ammonium chloride (OTAC) being superior due to the length of its alkyl‐carbon chain. And the quantized contribution of hydrophilic and hydrophobic groups of surfactants to the extraction of holocellulose and lignin, as well as, the different micromorphology of MRSP is obtained. Additionally, compared to the traditional PU (polyurethane) modified by eucalyptus wood powder (EWP/PU), the MRSP was used to prepare a series of biomass composite polyurethane synthetic leather (MRSP/PU), its tensile strength and peel strength of MRSP/PU coatings are greatly enhanced at the feedstock of 18 %.

Claudin is a promising biomarker of intestinal wall permeability

To date, sufficient information is available on changes in the levels of tight contact proteins (TCPs) in various diseases. Of greatest interest is the study of claudin due to numerous studies confirming the important role of this protein in the development of pathologies. Deafness, behavioural changes, and nerve conduction disorders occur due to insufficient claudin production. Claudin is involved in the maintenance of cell polarity due to its apical location in the cell. When pathological processes occur, claudin may undergo phosphorylation, leading to changes in cell polarity and impaired regulation of APC levels. Irritable bowel syndrome is one of the possible causes of impaired regulation of claudin levels. In this pathology there is adecrease in claudin-1 expression. In addition, claudins play different roles in different tumour tissues, and the same protein may be differentially expressed in different forms of cancer. Claudin-4 expression is upregulated as disease progresses in colorectal cancer (CRC), oesophageal squamous cell carcinoma, and its upregulation is associated with decreased invasiveness and metastatic potential, which is positively correlated with improved prognosis. In contrast, overexpression of CLDN 4 in breast cancer (BC) and pancreatic cancer (PC) is positively correlated with invasion, metastasis, angiogenesis and poor prognosis. Aim: systematisation of available data on the biological role and clinical significance of claudin. Materials: review of Russian and foreign literature from 2013-2023.

Neutrophil extracellular traps promote M1 macrophage polarization in gouty inflammation via targeting hexokinase-2

Peptidylarginine deiminase 4 (PAD4)-dependent neutrophil extracellular trap (NET) formation is a new neutrophil death mechanism. Increased NET formation has been demonstrated to be associated with gouty inflammation. Macrophages release proinflammatory mediators and chemokines in acute gouty inflammation and subsequently lead to inflammatory cascades. However, whether NETs regulate macrophage function and polarization and further contribute to gout development remains unclear. Herein, we investigated the relationship between monosodium urate (MSU) crystal-induced NETs and macrophages and the associated mechanisms in gouty inflammation. Elevated NET formation and CD86+ macrophage infiltration were observed in human gouty arthritis (GA). In vitro, MSU crystal-induced NETs or NET-associated histone H3 treatments modulated nod-like receptor protein 3 (NLRP3) inflammasome activation, M1 polarization, and metabolic changes in macrophages. These effects were eliminated by hexokinase-2 (HK-2) silencing. Moreover, NET formation and inflammation were significantly reduced in PAD4−/− GA mice. Pharmacological inhibition of NET formation with Cl-Amidine or NET degradation with DNase Ⅰ significantly reduced M1 polarization of macrophages and ameliorated inflammation in GA mice. In sum, MSU crystal-induced NETs promote M1 polarization and NLRP3 activation in macrophages via targeting HK-2. Cell-free DNA and histone H3 may be the driving elements behind the NET-induced M1 macrophage polarization, NLRP3 activation, and metabolic changes. Targeting NETs could be a potential therapeutic strategy for gout flare.