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Dielectric materials play an important role in devices for energy conversion and storage. Based on first-principles calculations, novel two-dimensional Janus GaOClX (X = F, Br, and I) monolayers with superior energy storage properties are predicted. They are indirect-bandgap semiconductors with bandgaps in the range of 2.18-4.36 eV, and possess anisotropic carrier mobility, strong mechanical flexibility, and excellent out-of-plane piezoelectricity. More importantly, it is found that the GaOCl monolayer and Janus GaOClX monolayers could exhibit an ultrahigh energy storage density (as high as 893.32 J cm-3) comparable to those of electrochemical supercapacitors and batteries, unparalleled by other dielectric materials reported to date. This work opens up a new window in searching for novel dielectric materials, which could be used in dielectric capacitors with superior energy storage density and power density, excellent efficiency and thermal stability.
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InSeBr-Type monolayers, ternary In(Se,S)(Br,Cl) compounds, are typical two-dimensional (2D) Janus materials and can be exfoliated from their bulk crystals. The structural stability, electronic properties, mechanical flexibility, and intrinsic piezoelectricity of these InSeBr-type 2D Janus monolayers are comprehensively investigated by first-principles calculations. Our calculations show that the stable InSeBr-type monolayers exhibit ultrahigh mechanical flexibility with low Young's moduli. Due to the amazing flexibility of the InSeBr monolayer with an ultra-low Young's modulus of 0.81 N m-1, the piezoelectric strain coefficient d11 can reach 103 pm V-1 orders of magnitude (around 2361-3224 pm V-1), which is larger than those of reported 2D materials and even superior to those of conventional perovskite bulk materials. Such a superior piezoelectric response of InSeBr-type monolayers could facilitate their practical applications in sensors and energy harvesters.
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Due to their broken out-of-plane inversion symmetry, Janus two-dimensional (2D) materials exhibit some exceptional and interesting physical properties and have recently attracted increasing attention. Herein, based on first-principles calculations, we propose a series of Janus 2D titanium nitride halide TiNX0.5Y0.5 (X, Y = F, Cl, or Br, and X ≠ Y) monolayers constructed from 2D ternary compounds TiNX (X = F, Cl, or Br), where the halogen atoms X or Y are located on each side of the monolayer, respectively. Our calculations confirm that the Janus monolayers are both dynamically and thermally stable. As compared with those of perfect TiNX monolayers, the band-structure changes of Janus TiNX0.5Y0.5 monolayers are very limited and the corresponding bandgaps only increase by about 0.1-0.2 eV. Meanwhile, the Janus TiNX0.5Y0.5 monolayers show remarkable out-of-plane piezoelectricity by virtue of their broken centrosymmetry. The calculated out-of-plane piezoelectric coefficient d31 is as high as 0.34 pm V-1, which is larger than those of most 2D piezoelectric materials reported previously. In addition, it is found that the formation of Janus structures could effectively improve the carrier mobility. The hole mobilities along the x-direction (y-direction) of Janus TiNF0.5Cl0.5 and TiNF0.5Br0.5 monolayers reach as high as 5402 (5118) and 5538 (4135) cm2 V-1 s-1 at 300 K, respectively, which is almost twice as large as those of perfect TiNX monolayers. The giant out-of-plane piezoelectricity and high carrier mobility of Janus TiNX0.5Y0.5 monolayers suggest that these novel 2D materials could be promising for applications in electronic and piezoelectric devices.
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In this work, amorphous Fe-Co-P films prepared by electrodeposition are found to exhibit dense microstructures with amorphous grains. Through a pulse electrodeposition synthesis route, complex microstructures containing nano-sized grains are obtained in the amorphous alloy films. The nanostructured Fe-Co-P amorphous alloys show superior soft magnetic and magnetocaloric properties as compared with those of other iron-based soft magnetic amorphous alloys reported to date. The coercive field of samples can be as small as 1.6 Oe at room temperature. The magnetocaloric effect (MCE) of the ternary amorphous alloys has been investigated by evaluating the magnetic entropy changes, |ΔSM |, from their temperature-dependent magnetization behaviors. The |ΔSM| values are as high as 1.846 J kg-1 K-1 with an applied magnetic field of 10 kOe. With a temperature span of 90 K, the refrigerant capacity of samples can be as high as 118.64 J kg-1. The nanostructure enabled giant MCE in Fe-Co-P amorphous alloys is discussed.
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Low-dimensional materials have aroused widespread interest for their novel and fascinating properties. Based on first-principles calculations, we predict the one-dimensional (1D) InSeI nanochains with van der Waals (vdW) interchain interactions, which could be exfoliated mechanically and kept at steady states at room temperature. Compared with bulk InSeI, the single nanochain InSeI has a larger direct bandgap of 3.15 eV. Its calculated carrier mobility is as high as 54.17 and 27.49 cm2 V-1 s-1 for holes and electrons, respectively, comparable with those of other 1D materials. In addition, a direct-to-indirect bandgap transition is implemented under a small applied strain (â¼6%). More importantly, the nanochains are found to be promising candidates for optoelectronic devices since they possess a high absorption coefficient of â¼105 cm-1 in the ultraviolet region. The results thus pave a novel avenue for the applications of InSeI nanochains with excellent thermal stability in nanoelectronic and optoelectronic devices.
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Rational structure design of microwave absorption material is extremely significant from the perspectives of enhancing the electromagnetic microwave absorption (EMA) performance and adapting to cost-effective and sustainable industrial applications. Here, reduced graphene oxides (rGOs) with curl structures derived from corn stover are applied for the absorption of electromagnetic waves. The results suggest that biomass-rGO show the maximum reflection loss of -51.7 dB and an effective absorption bandwidth 13.5 GHz (4.5-18 GHz) at a thickness of 3.25 mm, implying the unique critical role of the microstructure in adjusting the EMA performance. Moreover, the successful conversion of waste biomass into widely used electromagnetic wave absorbing materials could solve the problems of environmental pollution caused by straw burning.
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Looking for the high-performance alternatives to conventional lead-containing piezoelectric materials such as lead zirconate titanate (PZT) is absolutely vital for the development of low-dimensional innovative piezoelectric devices. Herein, we present our first-principles calculations on several new monolayers consisting of ternary In-containing sesquichalcogenides, which exhibit high stability and extraordinary piezoelectric properties. Our calculations predict that the in-plane (d11) and out-of-plane (d31) piezoelectric coefficients of BiInSe3, SbInSe3, BiInTe3, and SbInTe3 monolayers are much larger than those of most previously reported two-dimensional (2D) materials and widely studied wurtzite-type bulk piezoelectrics. Very strikingly, BiInTe3 monolayer possesses a d11 as high as 362 pm V-1 due to its mechanical flexibility, which is the highest among those reported in 2D materials and for the first time reaches those (â¼360 pm V-1) in bulk lead-containing piezoelectric materials such as PZT. The theoretical predictions of the giant piezoelectricity in these 2D materials suggest that they have great potentials for the applications in atomically thin lead-free piezoelectric devices such as sensors and energy harvesters.
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Multiferroics have broad application prospects in various fields such as multi-layer ceramic capacitors and multifunctional devices owing to their high dielectric constants and coupled magnetic and ferroelectric properties at room temperature. In this study, cobalt ferrite (CFO)/barium calcium titanate (BCT) composite fibers are prepared from BCT and CFO sols by an electrospinning method, and are then oriented by magnetic fields and sintered at high temperatures. The effects of magnetic fields and CFO contents on the nanostructures and magnetoelectric properties of the composites are investigated. Strong coupling between magnetic and ferroelectric properties occurs in CFO/BCT composites with magnetic orientation. More interestingly, the dielectric constants of CFO/BCT composites with magnetic orientation are found to be enhanced (by â¼1.5-3.5 times) as compared with those of BCT and CFO/BCT without magnetic orientation. The boost of dielectric constants of magnetic-field orientated CFO/BCT is attributed to the magneto-electrical coupling between CFO and BCT, where the polar domains of BCT are pinned by the orientated CFO. Therefore, this work not only provides a novel and effective approach in enhancing the dielectric constants of ceramic ferroelectrics, which is of tremendous value for industrial applications, but also elucidates the interaction mechanisms between ferromagnetic phase and ferroelectric phase in multiferroic compounds.
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Two-dimensional (2D) piezoelectric materials have potential applications in miniaturized sensors and energy conversion devices. In this work, using first-principles simulations at different scales, we systematically study the electronic structures and piezoelectricity of a series of 2D monolayer phosphorene oxides (POs). Our calculations show that the monolayer POs have tunable band gaps along with remarkable piezoelectric properties. The calculated piezoelectric coefficient d11 of 54 pm V-1 in POs is much larger than those of 2D transition metal dichalcogenide monolayers and the widely used bulk α-quartz and AlN, and almost reaches the level of the piezoelectric effect in recently discovered 2D GeS. Furthermore, two other considerable piezoelectric coefficients, i.e., d31 and d26 with values of -10 pm V-1 and 21 pm V-1, respectively, are predicted in some monolayer POs. We also examine the correlation between the piezoelectric coefficients and energy stability. The enhancement of piezoelectricity for monolayer phosphorene by oxidation will broaden the applications of phosphorene and phosphorene derivatives in nano-sized electronic and piezotronic devices.
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A series of composites consisting of anatase TiO2 nanocrystals and three-dimensional (3D) graphene aerogel (TiO2-GA) were self-assembled directly from tetrabutyl titanate and graphene oxides via a one-pot hydrothermal process. TiO2 was found to uniformly distribute inside the 3D network of GA in the resulting composites with large surface areas (SBET > 125 m(2) g(-1)) and high pore volumes (Vp > 0.22 cm(3) g(-1)). In comparison with GA and TiO2, the composites possessed much higher adsorption capacities and visible light photocatalytic activity in the degradation of rhodamine B (RhB). With an initial concentration of 20.0 mg L(-1) of RhB, the adsorptive decolourization of RhB was as high as 95.1% and the total decolourization value reached up to 98.7% under visible light irradiation over 5.0 mg of the resulting composites. It was elucidated that the physical and chemical properties of the TiO2-GA composites could be ascribed to their unique 3D nanoporous structure with high surface areas and the synergetic activities of graphene nanosheets and TiO2 nanoparticles.
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INTRODUCTION: CO2 pneumoperitoneum has been used to establish an operation space in laparoscopic surgery. It may have some bad consequences, such as respiratory and circulatory system changes, hypotension and hypoxia in infants and the release of free tumor cells into the abdominal cavity. Gasless laparoscopic technique can avoid these adverse effects. But present gasless laparoscopic techniques have their own disadvantages. The main shortcoming of gasless laparoscopic techniques is inadequate operative space. MATERIAL AND METHODS: We herein describe a new technique. We used a self-designed spindle-like abdominal wall-lifting device to perform gasless laparoscopic cholecystectomy in seven pigs, recording the operation time, bleeding volume and unexpected occurrences during the operation. RESULTS: Seven pigs underwent laparoscopic cholecystectomy using this technique with no conversion to open operation. The operation time was between 21 minutes and 65 minutes, with a mean operative time of 42.5 minutes. The range of bleeding volumes was 2 ml to 8 ml, with a mean operative bleeding volume of 4.3 ml. There were no massive hemorrhages, internal organ injuries or other complications during the operation. CONCLUSIONS: These preliminary outcomes indicate that the spindle-like abdominal wall-lifting device is feasible and safe in gasless laparoscopic cholecystectomy, which can provide sufficient exposure of the operative filed.
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Parede Abdominal , Colecistectomia Laparoscópica/instrumentação , Colecistectomia Laparoscópica/métodos , Animais , Desenho de Equipamento , Hemorragia , Duração da Cirurgia , Pneumoperitônio Artificial , SuínosRESUMO
Shear banding is much dependent on the glass-glass interfaces (GGIs) in metallic nanoglasses (NGs). Nevertheless, the current understanding of the glass phase of GGIs is not well established for controlling the shear banding in NGs. In this study, Co-P NGs are investigated by molecular dynamics simulations to reveal the phenomenon of elemental segregation in the GGI regions where the content of Co is dominant. Specifically, Co segregation results in the formation of GGIs, whose atomic structures are comparatively less dense than those present in the interiors of glassy grains. It is suggested that the Co segregation significantly reduces the shear resistance of GGIs. Thus, such compositional heterogeneity influences the mechanical properties of Co-P NGs. Particularly, shear banding is much altered through enhancing the Co segregation in the GGI regions, which leads to improvements in the ductility of Co-P NGs. This study advances knowledge of the formation of the GGI phase in NGs, which could enable GGI engineering in enhancing the mechanical properties of NGs.
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The glass-glass interfaces (GGIs) are in a unique glass phase, while current knowledge on the interfacial phase has not completely established to explain the unprecedented improvements in the ductility of metallic nanoglasses (NGs). In this work, Co-P NGs prepared through the pulse electrodeposition are investigated, whose GGI regions clearly show elemental segregation with chemical composition dominated by element Co. Such compositional heterogeneity is further verified by molecular dynamics (MD) simulation on the formation of GGIs in Co-P NGs and atomic structures of GGIs with Co segregation are found to be less dense than those of glassy grains. More importantly, Co segregation at GGIs is closely related to the improved ductility observed in Co-P NGs, as demonstrated by nanoindentation measurements and MD simulations. This work facilitates the understanding on the relations between compositional heterogeneity and improved ductility as observed in Co-P NGs, and thus opens a new window for controlling the mechanical properties of NGs through GGI engineering.
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Ni-Mn-Sn-based ferromagnetic shape memory alloys (FSMAs) are multifunctional materials that are promising for solid-state refrigeration applications based on the magnetocaloric effect (MCE) and elastocaloric effect (eCE). However, a combination of excellent multi-caloric properties, suitable operating temperatures, and mechanical properties cannot be well achieved in these materials, posing a challenge for their practical application. In this work, we systematically study the phase transformations and magnetic properties of Ni50-xMn38Sn12Cux (x = 0, 2, 3, 4, 5, and 6) and Ni50-yMn38Sn12Fey (y = 0, 1, 2, 3, 4, and 5) alloys, and the magnetic-structural phase diagrams of these alloy systems are reported. The influences of the fourth-element doping on the phase transitions and magnetic properties of the alloys are elucidated by first-principles calculations. This work demonstrates that the fourth-element doping of Ni-Mn-Sn-based FSMA is effective in developing multicaloric refrigerants for practical solid-state refrigeration.
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Background: Previous studies have confirmed that malignant transformation of dysplastic nodule (DN) into hepatocellular carcinoma (HCC) is accompanied by reduction of iron content in nodules. This pathological abnormality can serve as the basis for magnetic resonance imaging (MRI). This study was designed to identify the feasibility of iterative decomposition of water and fat with echo asymmetry and least squares estimation-iron quantitative (IDEAL-IQ) measurement to distinguish early hepatocellular carcinoma (eHCC) from DN. Methods: We reviewed MRI studies of 35 eHCC and 23 DN lesions (46 participants with 58 lesions total, 37 males, 9 females, 31-80 years old). The exams include IDEAL-IQ sequence and 3.0T MR conventional scan [including T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and Gadopentic acid (Gd-GDPA)-enhanced]. Then, 3 readers independently diagnosed eHCC, DN, or were unable to distinguish eHCC from DN using conventional MRI (CMRI), and then assessed R2* value of nodules [R2* value represents the nodule iron content (NIC)] and R2* value of liver background [R2* value represents the liver background iron content (LBIC)] with IDEAL-IQ. Statistical analysis was conducted using the t-test for comparison of means, the Mann-Whitney test for comparison of medians, the chi-square test for comparison of frequencies, and diagnostic efficacy was evaluated by using receiver operating characteristic (ROC) curve. Results: This study evaluated 35 eHCC participants (17 males, 6 females, 34-81 years old, nodule size: 10.5-27.6 mm, median 18.0 mm) and 23 DN participants (20 males, 3 females, 31-76 years old, nodule size: 16.30±4.095 mm). The NIC and ratio of NIC to LIBC (NIC/LBIC) of the eHCC group (35.926±12.806 sec-1, 0.327±0.107) was lower than that of the DN group (176.635±87.686 sec-1, 1.799±0.629) (P<0.001). Using NIC and NIC/LBIC to distinguish eHCC from DN, the true positive/false positive rates were 91.3%/94.3% and 87.0%/97.1%, respectively. The rates of CMRI, NIC and NIC/LBIC in diagnosis of eHCC were 77.1%, and 94.3%, 97.1%, respectively, and those of DN were 65.2%, 91.3%, and 87.0%, respectively. The diagnosis rate of eHCC and DN by CMRI was lower than that of NIC and NIC/LBIC (eHCC: P=0.03, 0.04, DN: P=0.02, 0.04). Conclusions: Using IDEAL-IQ measurement can distinguish DN from eHCC.
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Background: Pulmonary nodular consolidation (PN) and pulmonary cavity (PC) may represent the two most promising imaging signs in differentiating multidrug-resistant (MDR)-pulmonary tuberculosis (PTB) from drug-sensitive (DS)-PTB. However, there have been concerns that literature described radiological feature differences between DS-PTB and MDR-PTB were confounded by that MDR-PTB cases tend to have a longer history. This study seeks to further clarify this point. Methods: All cases were from the Guangzhou Chest Hospital, Guangzhou, China. We retrieved data of consecutive new MDR cases [n=46, inclusive of rifampicin-resistant (RR) cases] treated during the period of July 2020 and December 2021, and according to the electronic case archiving system records, the main PTB-related symptoms/signs history was ≤3 months till the first computed tomography (CT) scan in Guangzhou Chest Hospital was taken. To pair the MDR-PTB cases with assumed equal disease history length, we additionally retrieved data of 46 cases of DS-PTB patients. Twenty-two of the DS patients and 30 of the MDR patients were from rural communities. The first CT in Guangzhou Chest Hospital was analysed in this study. When the CT was taken, most cases had anti-TB drug treatment for less than 2 weeks, and none had been treated for more than 3 weeks. Results: Apparent CT signs associated with chronicity were noted in 10 cases in the DS group (10/46) and 9 cases in the MDR group (10/46). Thus, the overall disease history would have been longer than the assumed <3 months. Still, the history length difference between DS patients and MDR patients in the current study might not be substantial. The lung volume involvement was 11.3%±8.3% for DS cases and 8.4%±6.6% for MDR cases (P=0.022). There was no statistical difference between DS cases and MDR cases both in PN prevalence and in PC prevalence. For positive cases, MDR cases had more PN number (mean of positive cases: 2.63 vs. 2.28, P=0.38) and PC number (mean of positive cases: 2.14 vs. 1.38, P=0.001) than DS cases. Receiver operating characteristic curve analysis shows, PN ≥4 and PC ≥3 had a specificity of 86% (sensitivity 25%) and 93% (sensitivity 36%), respectively, in suggesting the patient being a MDR cases. Conclusions: A combination of PN and PC features allows statistical separation of DS and MDR cases.
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Tuberculosis (TB) remains one of the major infectious diseases in the world with a high incidence rate. Drug-resistant tuberculosis (DR-TB) is a key and difficult challenge in the prevention and treatment of TB. Early, rapid, and accurate diagnosis of DR-TB is essential for selecting appropriate and personalized treatment and is an important means of reducing disease transmission and mortality. In recent years, imaging diagnosis of DR-TB has developed rapidly, but there is a lack of consistent understanding. To this end, the Infectious Disease Imaging Group, Infectious Disease Branch, Chinese Research Hospital Association; Infectious Diseases Group of Chinese Medical Association of Radiology; Digital Health Committee of China Association for the Promotion of Science and Technology Industrialization, and other organizations, formed a group of TB experts across China. The conglomerate then considered the Chinese and international diagnosis and treatment status of DR-TB, China's clinical practice, and evidence-based medicine on the methodological requirements of guidelines and standards. After repeated discussion, the expert consensus of imaging diagnosis of DR-PB was proposed. This consensus includes clinical diagnosis and classification of DR-TB, selection of etiology and imaging examination [mainly X-ray and computed tomography (CT)], imaging manifestations, diagnosis, and differential diagnosis. This expert consensus is expected to improve the understanding of the imaging changes of DR-TB, as a starting point for timely detection of suspected DR-TB patients, and can effectively improve the efficiency of clinical diagnosis and achieve the purpose of early diagnosis and treatment of DR-TB.
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Solid-state refrigeration technology is expected to replace conventional gas compression refrigeration technology because it is environmentally friendly and highly efficient. Among various solid-state magnetocaloric materials, Ni-Mn-based ferromagnetic shape memory alloys (SMAs) have attracted widespread attention due to their multifunctional properties, such as their magnetocaloric effect, elastocaloric effect, barocaloric effect, magnetoresistance, magnetic field-induced strain, etc. Recently, a series of in-depth studies on the thermal effects of Ni-Mn-based magnetic SMAs have been carried out, and numerous research results have been obtained. It has been found that poor toughness and cyclic stability greatly limit the practical application of magnetic SMAs in solid-state refrigeration. In this review, the influences of element doping, microstructure design, and the size effect on the strength and toughness of Ni-Mn-based ferromagnetic SMAs and their underlying mechanisms are systematically summarized. The pros and cons of different methods in enhancing the toughness of Ni-Mn-based SMAs are compared, and the unresolved issues are analyzed. The main research directions of Ni-Mn-based ferromagnetic SMAs are proposed and discussed, which are of scientific and technological significance and could promote the application of Ni-Mn-based ferromagnetic SMAs in various fields.
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The pathophysiology of osteoarthritis (OA) is closely linked to autophagy abnormalities in articular chondrocytes, the sole mature cell type in healthy cartilage. Nevertheless, the precise molecular mechanism remains uncertain. Previous research has demonstrated that leptin activates mTORC1 , thereby inhibiting chondrocyte autophagy during the progression of OA. In this study, it is demonstrated that the presence of leptin induces a substantial increase in the expression of STAT3, leading to a notable decrease in REDD1 expression and subsequent phosphorylation of p70S6K, a recognized downstream effector of mTORC1. Conversely, inhibition of leptin yields contrasting effects. Additionally, the potential advantages of utilizing a sustained intra-articular release of a leptin inhibitor (LI) via an injectable, thermosensitive poly(D,L-lactide)-poly(ethylene glycol)-poly(D,L-lactide) (PDLLA-PEG-PDLLA: PLEL) hydrogel delivery system for the purpose of investigating its impact on cartilage repair are explored. The study conducted on LI-loaded PLEL (PLEL@LI) demonstrates remarkable efficacy in inhibiting OA and displays encouraging therapeutic advantages in the restoration of subchondral bone and cartilage. These findings establish a solid foundation for the advancement of a pioneering treatment approach utilizing PLEL@LI for OA.
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Cartilagem Articular , Osteoartrite , Humanos , Autofagia , Cartilagem Articular/metabolismo , Condrócitos/metabolismo , Preparações de Ação Retardada/farmacologia , Hidrogéis/farmacologia , Leptina/antagonistas & inibidores , Leptina/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Osteoartrite/tratamento farmacológico , Fator de Transcrição STAT3/metabolismo , RegeneraçãoRESUMO
OBJECTIVE: This study aimed to investigate the potential mechanisms by which lysyl oxidase like 3 (LOXL3) affects the autophagy in chondrocytes in osteoarthritis (OA), specifically through the activation of mammalian target of rapamycin complex 1 (mTORC1). METHODS: To establish an OA model, rats underwent anterior cruciate ligament transection (ACLT). Chondrocytes were isolated from cartilage tissues and cultured. Western blotting was performed to assess the expression of LOXL3, Rheb, phosphorylation of p70S6K (p-p70S6K, a downstream marker of mTORC1), and autophagy markers. The autophagy of chondrocytes was observed using an immunofluorescence assay. RESULTS: The expression levels of both LOXL3 and Rheb proteins were upregulated in chondrocytes isolated from the OA model cartilage, in comparison to those from the normal cartilage. The silencing of LOXL3 resulted in a decrease in the protein levels of Rheb and p-p70S6K, as well as an increase in the expression of autophagy-related proteins. Additionally, the effect of LOXL3 could be reversed through the silencing of Rheb. The results of the immunofluorescence assay confirmed the impact of LOXL3 and Rheb on chondrocyte autophagy. CONCLUSION: LOXL3 inhibits chondrocyte autophagy by activating the Rheb and mTORC1 signaling pathways.