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2.
Prev Med Rep ; 42: 102741, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38721570

RESUMO

Background: The purpose of this study was to examine the relationship between sleep duration and risk of sarcopenia in in general U.S. population. Methods: Utilizing publicly available data from the National Health and Nutrition Examination Survey spanning from 2011 to 2014, we explored the association between sleep duration and prevalence of sarcopenia. To investigate their relationship, we conducted weighted multivariate logistic regression analysis, restricted cubic splines (RCS) curve, and subgroup analysis. Results: The study included 8,200 individuals, among whom 99 (0.9 %) had sarcopenia. The RCS curve revealed a U-shaped association of sarcopenia with sleep duration (P for nonlinearity = 0.020), showing that the risk of sarcopenia decreases with increasing sleep duration, reaching the lowest risk around 6.67 h. After controlling for underlying cofounders, compared to individuals with sleep duration < 5 h, the odds ratios with 95 % confidence intervals of sarcopenia were 0.64 (0.27, 1.49), 0.50 (0.20, 1.26), 0.65 (0.27, 1.60), and 2.31 (0.73, 7.30) for < 5-6, 6.5-7.5, 8-9, and > 9 h group. The U-shaped association between sleep time and prevalence of sarcopenia also was observed in the subjects who aged < 40 or ≥ 40 years, were male or female, with or without hypertension, and diabetes mellitus. Conclusions: In summary, both short and long sleep durations increased prevalence of sarcopenia. Further studies are needed to explore the underlying mechanisms.

3.
Small Methods ; : e2400177, 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38721966

RESUMO

This study addresses a crucial challenge in two-dimensional (2D) material-based electronic devices-inefficient heat dissipation across the van der Waals (vdW) interface connecting the 2D material to its three-dimensional (3D) substrate. The objective is to enhance the interfacial thermal conductance (ITC) of 2D/3D heterostructures without compromising the intrinsic thermal conductivities (κ) of 2D materials. Using 2D-MoS2/3D-GaN as an example, a novel strategy to enhance both the ITC across 2D/3D interface and κ of 2D material is proposed by introducing a controlled concentration (ρ) of vacancy defects to substrate's bottom surface. Molecular dynamics simulations demonstrate a notable 2.1-fold higher ITC of MoS2/GaN at ρ = 4% compared to the no-defective counterpart, along with an impressive 56% enhancement in κ of MoS2 compared to the conventional upper surface modification approaches. Phonon dynamics analysis attributes the ITC enhancement to increased phonon coupling between MoS2 and GaN, resulting from polarization conversion and hybridization of phonons at the defective surface. Spectral energy density analysis affirms that the improved κ of MoS2 directly results from the proposed strategy, effectively reducing phonon scattering at the interface. This work provides an effective approach for enhancing heat transfer in 2D/3D vdW heterostructures, promisingly advancing electronics' heat dissipation.

4.
Sci Rep ; 14(1): 10169, 2024 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-38702375

RESUMO

Bovine viral diarrhea virus (BVDV) is considered to be the most common agent of severe diarrhea in cattle worldwide, causing fever, diarrhea, ulcers, and abortion. Bovine herpesvirus 1 (BoHV-1) is also a major bovine respiratory disease agent that spreads worldwide and causes extensive damage to the livestock industry. Recombinase polymerase amplification (RPA) is a novel nucleic acid amplification method with the advantages of high efficiency, rapidity and sensitivity, which has been widely used in the diagnosis of infectious diseases. A dual RPA assay was developed for the simultaneous detection of BVDV and BoHV-1. The assay was completed at a constant temperature of 37 °C for 30 min. It was highly sensitive and had no cross-reactivity with other common bovine viruses. The detection rate of BVDV RPA in clinical samples (36.67%) was higher than that of PCR (33.33%), the detection rate of BoHV-1 RPA and PCR were equal. Therefore, the established dual RPA assay for BVDV and BoHV-1 could be a potential candidate for use as an immediate diagnostic.


Assuntos
Vírus da Diarreia Viral Bovina , Herpesvirus Bovino 1 , Técnicas de Amplificação de Ácido Nucleico , Recombinases , Animais , Bovinos , Herpesvirus Bovino 1/genética , Herpesvirus Bovino 1/isolamento & purificação , Técnicas de Amplificação de Ácido Nucleico/métodos , Recombinases/metabolismo , Vírus da Diarreia Viral Bovina/genética , Vírus da Diarreia Viral Bovina/isolamento & purificação , Sensibilidade e Especificidade , Doença das Mucosas por Vírus da Diarreia Viral Bovina/virologia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/diagnóstico , Infecções por Herpesviridae/veterinária , Infecções por Herpesviridae/virologia , Infecções por Herpesviridae/diagnóstico , DNA Viral/genética
5.
PNAS Nexus ; 3(5): pgae179, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38737767

RESUMO

Despite the success of combination antiretroviral therapy (ART) for individuals living with HIV, mild forms of HIV-associated neurocognitive disorder (HAND) continue to occur. Brain microglia form the principal target for HIV infection in the brain. It remains unknown how infection of these cells leads to neuroinflammation, neuronal dysfunction, and/or death observed in HAND. Utilizing two different inducible pluripotent stem cell-derived brain organoid models (cerebral and choroid plexus [ChP] organoids) containing microglia, we investigated the pathogenic changes associated with HIV infection. Infection of microglia was associated with a sharp increase in CCL2 and CXCL10 chemokine gene expression and the activation of many type I interferon stimulated genes (MX1, ISG15, ISG20, IFI27, IFITM3 and others). Production of the proinflammatory chemokines persisted at low levels after treatment of the cell cultures with ART, consistent with the persistence of mild HAND following clinical introduction of ART. Expression of multiple members of the S100 family of inflammatory genes sharply increased following HIV infection of microglia measured by single-cell RNA-seq. However, S100 gene expression was not limited to microglia but was also detected more broadly in uninfected stromal cells, mature and immature ChP cells, neural progenitor cells and importantly in bystander neurons suggesting propagation of the inflammatory response to bystander cells. Neurotransmitter transporter expression declined in uninfected neurons, accompanied by increased expression of genes promoting cellular senescence and cell death. Together, these studies underscore how an inflammatory response generated in HIV-infected microglia is propagated to multiple uninfected bystander cells ultimately resulting in the dysfunction and death of bystander neurons.

6.
J Psycholinguist Res ; 53(3): 45, 2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38739304

RESUMO

English is widely regarded as a global language, and it has become increasingly important for global communication. As a result, the demand for English language education has been on the rise. In China, a significant number of individuals are engaged in learning the English language. However, many English learners in China encounter challenges when it comes to developing their speaking skills. This study aims to investigate the factors influencing the speaking skills of English learners in China. Employing a mixed-methods approach, data were collected through a questionnaire from 455 college students from three different courses (arts, science & business, and commerce) in China. The study findings identified several factors impacting the speaking skills of English learners in China, including limited opportunities for speaking practice, fear of making mistakes, limited exposure to English-speaking environments, inadequate teacher training, and the influence of the Chinese language on English pronunciation. Additionally, the study highlighted that learners who have greater exposure to English-speaking environments and more opportunities for speaking practice tend to demonstrate better speaking skills. The novelty of this study lies in its valuable insights into the factors influencing the speaking skills of English learners in China. Based on the findings, it is recommended that English teachers receive enhanced training to effectively teach speaking skills, and learners should be provided with increased opportunities for speaking practice, such as participating in group discussions or engaging in speaking activities.


Assuntos
Aprendizagem , Humanos , China , Feminino , Masculino , Aprendizagem/fisiologia , Adulto Jovem , Multilinguismo , Fala , Idioma , Estudantes/psicologia , Adulto , Inquéritos e Questionários , Fonética , População do Leste Asiático
8.
Exp Neurol ; 376: 114774, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38599367

RESUMO

Peripheral nerve injury (PNI) resulting from trauma or neuropathies can cause significant disability, and its prognosis deteriorates with age. Emerging evidence suggests that gut dysbiosis and reduced fecal short-chain fatty acids (SCFAs) contribute to an age-related systemic hyperinflammation (inflammaging), which hinders nerve recovery after injury. This study thus aimed to evaluate the pro-regenerative effects of a rejuvenating fecal microbiota transplant (FMT) in a preclinical PNI model using aged mice. Aged C57BL/6 mice underwent bilateral crush injuries to their sciatic nerves. Subsequently, they either received FMT from young donors at three and four days after the injury or retained their aged gut microbiota. We analyzed gut microbiome composition and SCFA concentrations in fecal samples. The integrity of the ileac mucosal barrier was assessed by immunofluorescence staining of Claudin-1. Flow cytometry was utilized to examine immune cells and cytokine production in the ileum, spleen, and sciatic nerve. Various assessments, including behavioural tests, electrophysiological studies, and morphometrical analyses, were conducted to evaluate peripheral nerve function and repair following injury. Rejuvenating FMT reversed age-related gut dysbiosis by increasing Actinobacteria, especially Bifidobacteriales genera. This intervention also led to an elevation of gut SCFA levels and mitigated age-related ileac mucosal leakiness in aged recipients. Additionally, it augmented the number of T-helper 2 (Th2) and regulatory T (Treg) cells in the ileum and spleen, with the majority being positive for anti-inflammatory interleukin-10 (IL-10). In sciatic nerves, rejuvenating FMT resulted in increased M2 macrophage counts and a higher IL-10 production by IL-10+TNF-α- M2 macrophage subsets. Ultimately, restoring a youthful gut microbiome in aged mice led to improved nerve repair and enhanced functional recovery after PNI. Considering that FMT is already a clinically available technique, exploring novel translational strategies targeting the gut microbiome to enhance nerve repair in the elderly seems promising and warrants further evaluation.


Assuntos
Envelhecimento , Transplante de Microbiota Fecal , Microbioma Gastrointestinal , Camundongos Endogâmicos C57BL , Regeneração Nervosa , Animais , Camundongos , Transplante de Microbiota Fecal/métodos , Microbioma Gastrointestinal/fisiologia , Regeneração Nervosa/fisiologia , Masculino , Traumatismos dos Nervos Periféricos/terapia , Inflamação/metabolismo , Inflamação/terapia , Disbiose/terapia , Nervo Isquiático/lesões
9.
Opt Lett ; 49(8): 1888-1891, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38621031

RESUMO

A phase generated carrier (PGC) demodulation scheme is always accompanied by nonlinear errors. We propose a fusion of PGC differential and cross multiplying (PGC-DCM), geometric fitting, and arctangent (Atan) algorithms for fiber optic interferometric sensors to eliminate nonlinear errors. The output amplitude of the PGC-DCM algorithm is used to judge whether the Lissajous figure of quadrature signals is larger than 1/2 ellipse arc. When the Lissajous figure exceeds 1/2 ellipse arc, the contaminated quadrature signals are corrected by the ellipse correction parameters calculated from the geometric fitting; otherwise, the previous fitting parameters are employed for correction. Geometric fitting is realized by minimizing the Sampson error, and its failure problem under small signals is solved by using the temporary stability of fitting results. Finally, desired signals are extracted from the corrected quadrature signals by the Atan algorithm. Experimental results show that the fusion combines the merits of the three algorithms and expands the application of the geometric fitting in PGC demodulation schemes.

10.
Cell Mol Biol Lett ; 29(1): 48, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38589794

RESUMO

Clustered regularly interspaced short palindromic repeats and associated Cas protein (CRISPR-Cas), a powerful genome editing tool, has revolutionized gene function investigation and exhibits huge potential for clinical applications. CRISPR-Cas-mediated gene knockout has already become a routine method in research laboratories. However, in the last few years, accumulating evidences have demonstrated that genes knocked out by CRISPR-Cas may not be truly silenced. Functional residual proteins could be generated in such knockout organisms to compensate the putative loss of function, termed herein knockout escaping. In line with this, several CRISPR-Cas-mediated knockout screenings have discovered much less abnormal phenotypes than expected. How does knockout escaping happen and how often does it happen have not been systematically reviewed yet. Without knowing this, knockout results could easily be misinterpreted. In this review, we summarize these evidences and propose two main mechanisms allowing knockout escaping. To avoid the confusion caused by knockout escaping, several strategies are discussed as well as their advantages and disadvantages. On the other hand, knockout escaping also provides convenient tools for studying essential genes and treating monogenic disorders such as Duchenne muscular dystrophy, which are discussed in the end.


Assuntos
Sistemas CRISPR-Cas , Edição de Genes , Sistemas CRISPR-Cas/genética , Edição de Genes/métodos
11.
Org Lett ; 26(18): 3901-3905, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38666661

RESUMO

Two nitrogen-doped positively curved aromatic molecules bearing doubly fused pentagonal rings were synthesized and characterized. Crystallographic analysis confirms the formation of a bowl-shaped structure, which is induced by the fusion of adjacent pentagons to the rigid aromatic planes. Both compounds demonstrate good photoluminescence. These electron-rich bowl-shaped molecules can associate with C60 to form complexes in 2:1 ratio in toluene with different association constants depending on the molecular dimension of the hosts.

12.
Int Immunopharmacol ; 133: 112005, 2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38626543

RESUMO

BACKGROUND: Because the pathophysiology of osteoarthritis (OA) has not been fully elucidated, targeted treatments are lacking. In this study, we assessed the role and underlying mechanism apolipoprotein D (APOD) on the development of OA. METHODS: To establish an in vitro OA model, we extracted primary chondrocytes from the cartilage of C57BL/6 mice and stimulated the chondrocytes with IL-1ß. After APOD intervention or incubation with an overexpressing plasmid, we detected inflammatory-related markers using RT-qPCR, Western blotting, and ELISA. To detect apoptosis and autophagy-related markers, we used flow cytometry, immunofluorescence, and transmission electron microscopy (TEM). Finally, we measured the level of oxidative stress. We also used RNA-seq to identify the APOD-regulated downstream signaling pathways. We used an in vivo mice OA model of the anterior cruciate ligament transection (ACLT) and administered intra-articular adenovirus overexpressing APOD. To examine cartilage damage severity, we used immunohistochemical analysis (IHC), micro-CT, scanning electron microscopy (SEM), and Safranin O-fast green staining. RESULTS: Our results showed that APOD inhibited chondrocyte inflammation, degeneration, and apoptosis induced by IL-1ß. Additionally, APOD reversed autophagy inhibition and oxidative stress and also blocked activation of the PI3K/AKT/mTOR signaling pathway induced by IL-1ß. Finally, overexpression of the APOD gene through adenovirus was sufficient to mitigate OA progression. CONCLUSIONS: Our findings revealed that APOD had a chondroprotective role in OA progression by the PI3K/AKT/mTOR signaling pathway.


Assuntos
Apolipoproteínas D , Condrócitos , Camundongos Endogâmicos C57BL , Osteoartrite do Joelho , Fosfatidilinositol 3-Quinases , Proteínas Proto-Oncogênicas c-akt , Transdução de Sinais , Serina-Treonina Quinases TOR , Animais , Serina-Treonina Quinases TOR/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Condrócitos/metabolismo , Osteoartrite do Joelho/patologia , Osteoartrite do Joelho/metabolismo , Camundongos , Fosfatidilinositol 3-Quinases/metabolismo , Apolipoproteínas D/genética , Apolipoproteínas D/metabolismo , Masculino , Células Cultivadas , Apoptose , Autofagia , Modelos Animais de Doenças , Interleucina-1beta/metabolismo , Cartilagem Articular/patologia , Cartilagem Articular/metabolismo , Estresse Oxidativo
13.
Heliyon ; 10(6): e27622, 2024 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-38515733

RESUMO

Polygalae radix (PR) is a famous herbal medicine obtained by drying the root of Polygala tenuifolia Willd., one of the traditional Chinese medicines (TCM) that can be used for healthy food. There are three main processed methods of PR, including removing the xylem of roots (Polygalae Cortex, PC), frying PC with licorice (LP), and frying PC with honey (HP). While processing is believed to enhance efficacy and reduce toxicity, it is crucial to understand the differences in chemical composition and biological activities between crude and processed PR. This study used ultra-performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS/MS) combined with multivariate statistical analysis to analyze the chemical profiles and differences between the crude and processed products. Total polyphenol contents (TPC), total flavonoid contents (TFC), total saponin contents (TSC) and antioxidant activity of the processed and crude PR were also investigated. A total of 131 chemical compounds, including 42 saponins, 44 oligosaccharide esters, 25 xanthones, 2 organic acids, 3 Carbohydrates, and 15 components detected in auxiliary materials, were detected in all samples. Notably, PC exhibited significant changes among the three processed products, with the content of 62 compounds being higher. Processing of licorice (LP) and honey (HP) decreased the content of several compounds due to temperature and moisture influences. Comprehensive comparison of the antioxidant capacity of crude and processed PR showed that the antioxidant capacity of PC was higher than that of PR, HP, and LP. Our results can provide a scientific basis for further developing and applying P. tenuifolia resources.

14.
ACS Appl Mater Interfaces ; 16(12): 14954-14964, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38497105

RESUMO

Al-Li alloys are feasible and promising additives in advanced energy and propellant systems due to the significantly enhanced heat release and increased specific impulse. The thermal properties of Al-Li alloys directly determine the manufacturing, storage safety, and ignition delay of propellants. In this study, a neural network potential (NNP) is developed to investigate the thermal behaviors of Al-Li alloys from an atomistic perspective. The novel NNP demonstrates an excellent predictive ability for energy, atomic force, mechanical behaviors, phonon vibrations, and dynamic evolutions. A series of NNP-based molecular dynamics simulations are performed to investigate the effect of Li doping on the thermal properties of Al-Li alloys. All calculated results for Al-Li alloys are consistent with experimental values for Al, ensuring their validity in predicting Al-Li interactions. The simulation results suggest that a minor increment in the Li content results in a slight change in the melting point, thermal expansion, and radical distribution functions. These three properties are associated with the lattice characteristics; nonetheless, it causes a substantial reduction in thermal conductivity, which is related to the physical properties of the elements. The lower thermal conductivity allows heat accumulation on the particle surface, thereby speeding up the surface premelt and ignition. This provides an alternative atomic explanation for the improved combustion performance of Al-Li alloys. These findings integrate insights from the field of alloy material science into crucial combustion applications, serving as an atomistic guide for developing manufacturing techniques.

15.
EMBO Mol Med ; 16(4): 854-869, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38467839

RESUMO

Lung adenocarcinoma (LUAD) continues to pose a significant mortality risk with a lack of dependable biomarkers for early noninvasive cancer detection. Here, we find that aberrant lipid metabolism is significantly enriched in lung cancer cells. Further, we identified four signature lipids highly associated with LUAD and developed a lipid signature-based scoring model (LSRscore). Evaluation of LSRscore in a discovery cohort reveals a robust predictive capability for LUAD (AUC: 0.972), a result further validated in an independent cohort (AUC: 0.92). We highlight one lipid signature biomarker, PE(18:0/18:1), consistently exhibiting altered levels both in cancer tissue and in plasma of LUAD patients, demonstrating significant predictive power for early-stage LUAD. Transcriptome analysis reveals an association between increased PE(18:0/18:1) levels and dysregulated glycerophospholipid metabolism, which consistently displays strong prognostic value across two LUAD cohorts. The combined utility of LSRscore and PE(18:0/18:1) holds promise for early-stage diagnosis and prognosis of LUAD.


Assuntos
Adenocarcinoma de Pulmão , Neoplasias Pulmonares , Humanos , Lipidômica , Detecção Precoce de Câncer , Adenocarcinoma de Pulmão/diagnóstico , Neoplasias Pulmonares/diagnóstico , Lipídeos
16.
Plants (Basel) ; 13(4)2024 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-38498526

RESUMO

Prefoldins (PFDs) are ubiquitous co-chaperone proteins that originated in archaea during evolution and are present in all eukaryotes, including yeast, mammals, and plants. Typically, prefoldin subunits form hexameric PFD complex (PFDc) that, together with class II chaperonins, mediate the folding of nascent proteins, such as actin and tubulin. In addition to functioning as a co-chaperone in cytoplasm, prefoldin subunits are also localized in the nucleus, which is essential for transcription and post-transcription regulation. However, the specific and critical roles of prefoldins in plants have not been well summarized. In this review, we present an overview of plant prefoldin and its related proteins, summarize the structure of prefoldin/prefoldin-like complex (PFD/PFDLc), and analyze the versatile landscape by prefoldin subunits, from cytoplasm to nucleus regulation. We also focus the specific role of prefoldin-mediated phytohormone response and global plant development. Finally, we overview the emerging prefoldin-like (PFDL) subunits in plants and the novel roles in related processes, and discuss the next direction in further studies.

17.
Comput Methods Programs Biomed ; 248: 108119, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38520785

RESUMO

BACKGROUND AND OBJECTIVE: Image segmentation of histopathology of colorectal cancer is a core task of computer aided medical image diagnosis system. Existing convolutional neural networks generally extract multi-scale information in linear flow structures by inserting multi-branch modules, which is difficult to extract heterogeneous semantic information under multi-level and different receptive field and tough to establish context dependency among different receptive field features. METHODS: To address these issues, we propose a symmetric spiral progressive feature fusion encoder-decoder network called the Symmetric Conical Network (SC-Net). First, we design a Multi-scale Feature Extraction Block (MFEB) matching with the Symmetric Conical Network to obtain multi-branch heterogeneous semantic information under different receptive fields, so as to enrich the diversity of extracted feature information. The encoder is composed of MFEB through spiral and multi-branch arrangement to enhance context dependence between different information flow. Secondly, the information loss of contour, color and others in high-level semantic information through causally stacking MFEB, the Feature Mapping Layer (FML) is designed to map low-level features to high-level semantic features along the down-sampling branch and solve the problem of insufficient global feature extraction in deep levels. RESULTS: The SC-Net was evaluated on our self-constructed colorectal cancer dataset, a publicly available breast cancer dataset and a polyp dataset. The results revealed that the mDice of segmentation reached 0.8611, 0.7259 and 0.7144. We compare our model with the state-of-art semantic segmentation UNet++, PSPNet, Attention U-Net, R2U-Net and other advanced segmentation networks. The experimental results demonstrate that we achieve the most advanced performance. CONCLUSIONS: The results indicate that the proposed SC-Net excels in segmenting H&E stained pathology images, effectively preserving morphological features and spatial information even in scenarios with weak texture, poor contrast, and variations in appearance.


Assuntos
Neoplasias Colorretais , Pólipos , Humanos , Diagnóstico por Computador , Redes Neurais de Computação , Semântica , Neoplasias Colorretais/diagnóstico por imagem , Processamento de Imagem Assistida por Computador
18.
Mater Horiz ; 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38545861

RESUMO

The growing need for high-power and compact-size microelectronic integrated circuits (ICs) in modern microelectronic industries and 5G communication systems demands low dielectric constant (κ) polymer dielectrics with excellent temperature capability, mechanical property and processability. However, conventional molecular design strategies often face difficulties of a trade-off between optimizing the dielectric performance of polymers and maintaining the aforementioned properties. Herein, we present an innovative and facile strategy that utilizes the space charge distribution characteristics of the target co-monomer to solve this trade-off. Based on this design strategy, a novel polyaryl ether ketone (PAEK) with two different charge distribution units (BAF and SBI) was designed and synthesized. Both the experimental results and computational simulations confirm that these two components serve to weaken the polarization of molecular chains in the electric field, induce higher molecular chain packing density and fewer weaknesses, and synchronously regulate the κ, dielectric loss (tan δ), thermal and mechanical properties and processability by generating a strong inter-chain electrostatic interaction. The resultant copolymer, PAEK-4F6S, exhibits exceptional low κ and tan δ values of 1.98 and 0.0024 at 1 MHz, respectively, and these values remain stable over a broad frequency (1-106 Hz, 8.2-12.4 GHz) and temperature range (30-150 °C). Furthermore, the resultant copolymer demonstrates excellent thermal stability and mechanical properties, with a glass transition temperature (Tg) of 195 °C, 5 wt% decomposition temperature (Td5%) of 498 °C under N2, tensile strength of 63.5 MPa and tensile modulus of 1011.2 MPa, respectively. The synthesis procedure of these resultant copolymers is facile, and they are found to have favorable solution and melt processing properties, making them suitable for processing and scalable production. More importantly, this design strategy is beneficial for lowering the κ and tan δ values, and simultaneously enhancing the comprehensive performances of the objective polymers, which provides a completely novel and facile approach for the design and fabrication of high performance low-κ polymers suitable for the needs of microelectronics and communication fields.

19.
Sci Total Environ ; 924: 171649, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38485018

RESUMO

Unstoppable global warming and increased frequency of extreme heat leads to human and animals easier to suffer from heat stress (HS), with gastrointestinal abnormalities as one of the initial clinical symptoms. HS induces intestinal mucosal damage owing to intestinal hypoxia and hyperthermia. Hypoxia-inducible factor 1α (HIF-1α) activates numerous genes to mediate cell hypoxic responses; however, its role in HS-treated intestinal mucosa is unknown. This work aimed to explore HIF-1α function and regulatory mechanisms in HS-treated pig intestines. We assigned 10 pigs to control and moderate HS groups. Physical signs, stress, and antioxidant levels were detected, and the intestines were harvested after 72 h of HS treatment to study histological changes and HIF-1α, heat shock protein 90 (HSP90), and prolyl-4-hydroxylase 2 (PHD-2) expression. In addition, porcine intestinal columnar epithelial cells (IPEC-J2) underwent HS treatment (42 °C, 5 % O2) to further explore the functions and regulatory mechanism of HIF-1α. The results of histological examination revealed HS caused intestinal villi damage and increased apoptotic epithelial cell; the expression of HIF-1α and HSP90 increased while PHD-2 showed and opposite trend. Transcriptome sequencing analysis revealed that HS activated HIF-1 signaling. To further explore the role of HIF-1α on HS induced IPEC-J2 apoptosis, the HIF-1α was interfered and overexpression respectively, and the result confirmed that HIF-1α could inhibited cell apoptosis under HS. Furthermore, HS-induced apoptosis depends on eukaryotic initiation factor 2 alpha (eif2α)/activating transcription factor 4 (ATF4)/CCAAT-enhancer-binding protein homologous protein (CHOP) pathway, and HIF-1α can inhibit this pathway to alleviate IPEC-J2 cell apoptosis. In conclusion, this study suggests that HS can promote intestinal epithelial cell apoptosis and cause pig intestinal mucosal barrier damage; the HIF-1α can alleviate cell apoptosis by inhibiting eif2α/ATF4/CHOP signaling. These results indicate that HIF-1α plays a protective role in HS, and offers a potential target for HS prevention and mitigation.


Assuntos
Apoptose , Resposta ao Choque Térmico , Subunidade alfa do Fator 1 Induzível por Hipóxia , Animais , Fator 4 Ativador da Transcrição/metabolismo , Apoptose/genética , Apoptose/fisiologia , Células Epiteliais/metabolismo , Fator de Iniciação 2 em Eucariotos/metabolismo , Resposta ao Choque Térmico/genética , Intestinos/metabolismo , Suínos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Fator de Transcrição CHOP/metabolismo , Transdução de Sinais
20.
Exp Cell Res ; 437(1): 113990, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38462207

RESUMO

This study aims to explore the role of methyltransferase-like 3 (METTL3) modulation of ferroptosis in the pathogenesis of trophoblast-mediated preeclampsia. The expression of METTL3 and acyl-CoA synthetase long chain family member 4 (ACSL4) was measured in clinical placental tissues and trophoblasts using qPCR and Western blot techniques. The effects of METTL3 on the symptoms of preeclampsia were also validated in rat models. METTL3 and ACSL4 were upregulated in placental tissues from patients with preeclampsia and in hypoxia-induced trophoblasts. METTL3 silencing increased the migration and invasion of trophoblasts cultured under hypoxic conditions. Knockdown of METTL3 increased cell viability and suppressed ferroptosis in hypoxia-stimulated trophoblasts. Hypoxia increased the level of m6A in cells, whereas silencing METTL3 partially reversed this change. Silencing METTL3 resulted in a decrease in m6A modification of ACSL4 mRNA, which led to a reduction in ACSL4 mRNA stability. ACSL4 upregulation partially reversed the effects of METTL3 silencing on cell viability, migration, invasion, and ferroptosis in hypoxia-stimulated trophoblasts. Inhibition of METTL3 in preeclampsia rats decreased blood pressure, urine protein levels, fetal survival rate, and ACSL4-mediated ferroptosis. METTL3 elevates ferroptosis to inhibit the migration and invasion of trophoblasts and in vivo preeclampsia symptoms by catalyzing the m6A modification of ACSL4 mRNA.


Assuntos
Ferroptose , Pré-Eclâmpsia , Animais , Feminino , Humanos , Gravidez , Ratos , Ferroptose/genética , Hipóxia , Metiltransferases/genética , Placenta , Pré-Eclâmpsia/genética , RNA Mensageiro , Trofoblastos
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