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1.
Development ; 151(7)2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38602507

RESUMO

CFAP58 is a testis-enriched gene that plays an important role in the sperm flagellogenesis of humans and mice. However, the effect of CFAP58 on bull semen quality and the underlying molecular mechanisms involved in spermatogenesis remain unknown. Here, we identified two single-nucleotide polymorphisms (rs110610797, A>G and rs133760846, G>T) and one indel (g.-1811_ g.-1810 ins147bp) in the promoter of CFAP58 that were significantly associated with semen quality of bulls, including sperm deformity rate and ejaculate volume. Moreover, by generating gene knockout mice, we found for the first time that the loss of Cfap58 not only causes severe defects in the sperm tail, but also affects the manchette structure, resulting in abnormal sperm head shaping. Cfap58 deficiency causes an increase in spermatozoa apoptosis. Further experiments confirmed that CFAP58 interacts with IFT88 and CCDC42. Moreover, it may be a transported cargo protein that plays a role in stabilizing other cargo proteins, such as CCDC42, in the intra-manchette transport/intra-flagellar transport pathway. Collectively, our findings reveal that CFAP58 is required for spermatogenesis and provide genetic markers for evaluating semen quality in cattle.


Assuntos
Análise do Sêmen , Sêmen , Humanos , Bovinos , Masculino , Animais , Camundongos , Cabeça do Espermatozoide , Espermatozoides , Camundongos Knockout
2.
J Immunol ; 212(4): 677-688, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38117276

RESUMO

During the initiation of the inflammatory response of microglia, the expression of many inflammation- and cell metabolism-related genes alters. However, how the transcription of inflammation- and metabolism-related genes are coordinately regulated during inflammation initiation is poorly understood. In this study, we found that LPS stimulation induced the expression of the chromatin target of PRMT1 (protein arginine methyltransferase 1) (CHTOP) in microglia. Knocking down CHTOP in microglia decreased proinflammatory cytokine expression. In addition, CHTOP knockdown altered cell metabolism, as both the upregulated genes were enriched in cell metabolism-related pathways and the metabolites profile was greatly altered based on untargeted metabolomics analysis. Mechanistically, CHTOP could directly bind the regulatory elements of inflammation and cell metabolism-related genes to regulate their transcription. In addition, knocking down CHTOP increased neuronal viability in vitro and alleviated microglia-mediated neuroinflammation in a systemic LPS treatment mouse model. Collectively, these data revealed CHTOP as a novel regulator to promote microglia-mediated neuroinflammation by coordinately regulating the transcription of inflammation and cell metabolism-related genes.


Assuntos
Microglia , Doenças Neuroinflamatórias , Animais , Camundongos , Expressão Gênica , Inflamação/metabolismo , Lipopolissacarídeos/metabolismo , Microglia/metabolismo
3.
J Biol Chem ; 300(7): 107453, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38852886

RESUMO

Identification of a conserved G-quadruplex in E165R of ASFVAfrican swine fever virus (ASFV) is a double-stranded DNA arbovirus with high transmissibility and mortality rates. It has caused immense economic losses to the global pig industry. Currently, no effective vaccines or medications are to combat ASFV infection. G-quadruplex (G4) structures have attracted increasing interest because of their regulatory role in vital biological processes. In this study, we identified a conserved G-rich sequence within the E165R gene of ASFV. Subsequently, using various methods, we verified that this sequence could fold into a parallel G4. In addition, the G4-stabilizers pyridostatin and 5,10,15,20-tetrakis-(N-methyl-4-pyridyl) porphin (TMPyP4) can bind and stabilize this G4 structure, thereby inhibiting E165R gene expression, and the inhibitory effect is associated with G4 formation. Moreover, the G4 ligand pyridostatin substantially impeded ASFV proliferation in Vero cells by reducing gene copy number and viral protein expression. These compelling findings suggest that G4 structures may represent a promising and novel antiviral target against ASFV.


Assuntos
Vírus da Febre Suína Africana , Antivirais , Quadruplex G , Vírus da Febre Suína Africana/genética , Vírus da Febre Suína Africana/metabolismo , Animais , Chlorocebus aethiops , Células Vero , Antivirais/farmacologia , Antivirais/química , Suínos , Febre Suína Africana/virologia , Febre Suína Africana/metabolismo , Porfirinas/química , Porfirinas/farmacologia , Ácidos Picolínicos/química , Ácidos Picolínicos/farmacologia , Ácidos Picolínicos/metabolismo , Replicação Viral/efeitos dos fármacos , Proteínas Virais/genética , Proteínas Virais/metabolismo , Proteínas Virais/química , Aminoquinolinas
4.
Nano Lett ; 2024 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-39096282

RESUMO

Spin-mechanical coupling is vital in diverse fields including spintronics, sensing, and quantum transduction. Two-dimensional (2D) magnetic materials provide a unique platform for investigating spin-mechanical coupling, attributed to their mechanical flexibility and novel spin orderings. However, studying their spin-mechanical coupling presents challenges in probing mechanical deformation and thermodynamic property changes at the nanoscale. Here we use nano-optoelectromechanical interferometry to mechanically detect the phase transition and magnetostriction effect in multilayer CrSBr, an air-stable antiferromagnet with large magnon-exciton coupling. The transitions among antiferromagnetism, spin-canted ferromagnetism, and paramagnetism are visualized. Nontrivial magnetostriction coefficient 2.3 × 10-5 and magnetoelastic coupling strength on the order of 106 J/m3 have been found. Moreover, we demonstrate the substantial tunability of the magnetoelastic constant by nearly 50% via gate-induced strain. Our findings demonstrate the strong spin-mechanical coupling in CrSBr and pave the way for developing sensitive magnetic sensing and efficient quantum transduction at the atomically thin limit.

5.
Horm Metab Res ; 56(7): 504-508, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38772392

RESUMO

The aim of the study was to assess the association between lipoprotein(a) [Lp(a)] concentration and incident type 2 diabetes. A meta-analysis of qualified studies on the relationship of low levels of Lp(a) concentration with incident type 2 diabetes was conducted. PubMed and Cochrane libraries were searched for randomized controlled trials containing data on events. Seven randomized trials with 227178 subjects were included in this analysis. We found an inverse association of the levels of Lp(a) concentration with risk of type 2 diabetes with approximately 37% lower relative risk in the group with the highest concentration compared with group with the lowest concentration. The current available evidence from prospective studies suggests that there is an inverse association between the levels of Lp(a) concentration and risk of type 2 diabetes, with a higher risk of type 2 diabetes at low levels of Lp(a) concentration. Therefore, we believe that the low levels of Lp(a) concentration is an independent predictor of incident type 2 diabetes.


Assuntos
Diabetes Mellitus Tipo 2 , Lipoproteína(a) , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/epidemiologia , Humanos , Lipoproteína(a)/sangue , Incidência , Fatores de Risco , Ensaios Clínicos Controlados Aleatórios como Assunto , Prognóstico
6.
J Org Chem ; 89(10): 7233-7242, 2024 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-38666895

RESUMO

A self-catalyzed, visible-light-induced, directly selective C3-H aroylation of quinoxalin-2(1H)-ones via energy transfer and hydrogen atom transfer (HAT) catalysis has been developed. The method is highly atom-economical, eco-friendly, and easy to handle. Notably, the reaction proceeded efficiently with ambient air as the sole oxidant at room temperature.

7.
Int J Mol Sci ; 25(12)2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38928420

RESUMO

Self-powered wearable pressure sensors based on flexible electronics have emerged as a new trend due to the increasing demand for intelligent and portable devices. Improvements in pressure-sensing performance, including in the output voltage, sensitivity and response time, can greatly expand their related applications; however, this remains challenging. Here, we report on a highly sensitive piezoelectric sensor with novel light-boosting pressure-sensing performance, based on a composite membrane of copper phthalocyanine (CuPC) and graphene oxide (GO) (CuPC@GO). Under light illumination, the CuPC@GO piezoelectric sensor demonstrates a remarkable increase in output voltage (381.17 mV, 50 kPa) and sensitivity (116.80 mV/kPa, <5 kPa), which are approximately twice and three times of that the sensor without light illumination, respectively. Furthermore, light exposure significantly improves the response speed of the sensor with a response time of 38.04 µs and recovery time of 58.48 µs, while maintaining excellent mechanical stability even after 2000 cycles. Density functional theory calculations reveal that increased electron transfer from graphene to CuPC can occur when the CuPC is in the excited state, which indicates that the light illumination promotes the electron excitation of CuPC, and thus brings about the high polarization of the sensor. Importantly, these sensors exhibit universal spatial non-contact adjustability, highlighting their versatility and applicability in various settings.


Assuntos
Grafite , Indóis , Luz , Compostos Organometálicos , Grafite/química , Indóis/química , Compostos Organometálicos/química , Dispositivos Eletrônicos Vestíveis
8.
Int J Mol Sci ; 25(15)2024 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-39125805

RESUMO

A previous study showed that high-glucose (HG) conditions induce mitochondria fragmentation through the calcium-mediated activation of extracellular signal-regulated kinase 1/2 (ERK 1/2) in H9C2 cells. This study tested whether empagliflozin could prevent HG-induced mitochondria fragmentation through this pathway. We found that exposing H9C2 cells to an HG concentration decreased cell viability and increased cell apoptosis and caspase-3. Empagliflozin could reverse the apoptosis effect of HG stimulation on H9C2 cells. In addition, the HG condition caused mitochondria fragmentation, which was reduced by empagliflozin. The expression of mitochondria fission protein was upregulated, and fusion proteins were downregulated under HG stimulation. The expression of fission proteins was decreased under empagliflozin treatment. Increased calcium accumulation was observed under the HG condition, which was decreased by empagliflozin. The increased expression of ERK 1/2 under HG stimulation was also reversed by empagliflozin. Our study shows that empagliflozin could reverse the HG condition, causing a calcium-dependent activation of the ERK 1/2 pathway, which caused mitochondria fragmentation in H9C2 cells.


Assuntos
Apoptose , Compostos Benzidrílicos , Cálcio , Glucose , Glucosídeos , Sistema de Sinalização das MAP Quinases , Mitocôndrias , Apoptose/efeitos dos fármacos , Compostos Benzidrílicos/farmacologia , Glucosídeos/farmacologia , Glucose/metabolismo , Mitocôndrias/metabolismo , Mitocôndrias/efeitos dos fármacos , Cálcio/metabolismo , Animais , Ratos , Linhagem Celular , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Dinâmica Mitocondrial/efeitos dos fármacos , Caspase 3/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Proteína Quinase 1 Ativada por Mitógeno/metabolismo
9.
Chin Med Sci J ; 39(1): 9-18, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38426412

RESUMO

Objective Aberrant expression of ATP binding cassette subfamily B member 1 (ABCB1) plays a key role in several cancers. However, influence of G protein coupled receptor family C group 5 type A (GPRC5A)-regulated ABCB1 expression on lung adenocarcinoma proliferation remains unclear. Therefore, this study investigated the effect of GPRC5A regulated ABCB1 expression on the proliferation of lung adenocarcinoma. Methods ABCB1 expressions in lung adenocarcinoma cell lines, human lung adenocarcinoma tissues, and tracheal epithelial cells and lung tissues of GPRC5A knockout mice and wild-type mice were analyzed with RT-PCR, Western blot, or immunohistochemical analysis. Cell counting kit-8 assay was performed to analyze the sensitivity of tracheal epithelial cells from GPRC5A knockout mice to chemotherapeutic agents. Subcutaneous tumor formation assay was performed to confirm whether down-regulation of ABCB1 could inhibit the proliferation of lung adenocarcinoma in vivo. To verify the potential regulatory relationship between GPRC5A and ABCB1, immunofluorescence and immunoprecipitation assays were performed. Results ABCB1 expression was up-regulated in lung adenocarcinoma cell lines and human lung adenocarcinoma tissues. ABCB1 expression in the tracheal epithelial cells and lung tissues of GPRC5Adeficient mice was higher than that in the wild type mice. Tracheal epithelial cells of GPRC5A knockout mice were much more sensitive to tariquidar and doxorubicin than those of GPRC5A wild type mice. Accordingly, 28 days after injection of the transplanted cells, the volume and weight of lung tumor in ABCB1knockout cell-transplanted GPRC5A-/-C57BL/6 mice were significantly smaller than those in wild type cell-transplanted mice (P= 0.0043, P= 0.0060). Furthermore, immunofluorescence and immunoprecipitation assays showed that GPRC5A regulated ABCB1 expression by direct binding.Conclusion GPRC5A reduces lung adenocarcinoma proliferation via inhibiting ABCB1 expression. The pathway by which GPRC5A regulates ABCB1 expression needs to be investigated.


Assuntos
Adenocarcinoma de Pulmão , Neoplasias Pulmonares , Animais , Humanos , Camundongos , Adenocarcinoma de Pulmão/genética , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Linhagem Celular Tumoral , Proliferação de Células , Neoplasias Pulmonares/patologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo
10.
Water Sci Technol ; 89(11): 3104-3121, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38877633

RESUMO

Coastal wetlands are the main distribution of blue carbon in coastal zones and well known for their high carbon sequestration capacity. Investigating the variation of carbon budget is crucial for understanding the functionality of coastal wetlands and effectively addressing climate change. In this study, a bibliometric analysis of 4,509 articles was conducted to reveal research progress, hot issues, and emerging trends in the coastal wetland carbon budget field. The number of publications and citations in this field increased exponentially from 1991 to 2022. The leading subject category was Environmental Sciences with 1,844 articles (40.9%). At present, studies have been focused on blue carbon, the effects of climate change and man-made disturbances on carbon cycle, and the restoration of coastal wetlands. Based on the hotspots and trends in this field, the future researches should include (1) exploring the functional mechanisms of various factors affecting carbon cycle and establishing a methodological system for the estimation of blue carbon in coastal wetlands; (2) researching restoration techniques of coastal wetland and constructing wetland restoration evaluation index system; and (3) formulating enforceable carbon trading policy and strengthening international cooperation.


Assuntos
Bibliometria , Carbono , Áreas Alagadas , Carbono/metabolismo , Mudança Climática
11.
BMC Psychol ; 12(1): 176, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38539260

RESUMO

The study aims to investigate the precise processes by which the advancement of physical education and technological progress leads to ecological conservation efforts within China's distinctive socio-cultural and economic framework. Acknowledging the pivotal role that economic advancement plays in a nation's environmental sustainability, this research utilizes cross-sectional quantitative data gathered using a five-point Likert scale survey. The sample size included 503 undergraduate students from Zhengzhou, China, and structural equation modeling was utilized to analyze the data. The study investigates how technology progress influences the relationship between compatibility, environmental sustainability, and the relative benefits of physical education. It fills the gap in the literature by illuminating how technical innovation and advanced physical education development contribute to China's pursuit of a sustainable environment. The findings emphasize the critical significance of higher physical education in fostering environmental sustainability. Furthermore, the research indicates that students participating in more rigorous physical education programs tend to possess a more well-rounded and mature mindset. This mindset is essential for healthy and long-lasting mental development, motivating individuals to critically consider environmental sustainability. The study provides valuable theoretical and practical insights that can be applied to enhance environmental sustainability in the country.


Assuntos
Invenções , Educação Física e Treinamento , Humanos , Estudos Transversais , China
12.
Comput Biol Med ; 174: 108379, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38631115

RESUMO

OBJECTIVE: Blurry medical images affect the accuracy and efficiency of multimodal image registration, whose existing methods require further improvement. METHODS: We propose an edge-based similarity registration method optimised for multimodal medical images, especially bone images, by a balance optimiser. First, we use a GPU (graphics processing unit) rendering simulation to convert computed tomography data into digitally reconstructed radiographs. Second, we introduce the improved cascaded edge network (ICENet), a convolutional neural network that extracts edge information of blurry medical images. Then, the bilateral Gaussian-weighted similarity of pairs of X-ray images and digitally reconstructed radiographs is measured. The a balanced optimiser is iteratively applied to finally estimate the best pose to perform image registration. RESULTS: Experimental results show that, on average, the proposed method with ICENet outperforms other edge detection networks by 20%, 12%, 18.83%, and 11.93% in the overall Dice similarity, overall intersection over union, peak signal-to-noise ratio, and structural similarity index, respectively, with a registration success rate up to 90% and average reduction of 220% in registration time. CONCLUSION: The proposed method with ICENet can achieve a high registration success rate even for blurry medical images, and its efficiency and robustness are higher than those of existing methods. SIGNIFICANCE: Our proposal may be suitable for supporting medical diagnosis, radiation therapy, image-guided surgery, and other clinical applications.


Assuntos
Osso e Ossos , Redes Neurais de Computação , Tomografia Computadorizada por Raios X , Humanos , Osso e Ossos/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Algoritmos , Imagem Multimodal/métodos , Processamento de Imagem Assistida por Computador/métodos
13.
Aging (Albany NY) ; 16(4): 3200-3230, 2024 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-38349858

RESUMO

BACKGROUND: Interstitial lung disease (ILD) encompasses a diverse group of disorders characterized by chronic inflammation and fibrosis of the pulmonary interstitium. Three ILDs, namely idiopathic pulmonary fibrosis (IPF), fibrotic hypersensitivity pneumonitis (fHP), and connective tissue disease-associated ILD (CTD-ILD), exhibit similar progressive fibrosis phenotypes, yet possess distinct etiologies, encouraging us to explore their different underlying mechanisms. METHODS: Transcriptome data of fibrotic lung tissues from patients with IPF, fHP, and CTD-ILD were subjected to functional annotation, network, and pathway analyses. Additionally, we employed the xCell deconvolution algorithm to predict immune cell infiltration in patients with fibrotic ILDs and healthy controls. RESULTS: We identified a shared progressive fibrosis-related module in these diseases which was related to extracellular matrix (ECM) degradation and production and potentially regulated by the p53 family transcription factors. In IPF, neuron-related processes emerged as a critical specific mechanism in functional enrichment. In fHP, we observed that B cell signaling and immunoglobulin A (IgA) production may act as predominant processes, which was further verified by B cell infiltration and the central role of CD19 gene. In CTD-ILD, active chemokine processes were enriched, and active dendritic cells (aDCs) were predicted to infiltrate the lung tissues. CONCLUSIONS: This study revealed shared and specific molecular and cellular pathways among IPF, fHP, and CTD-ILD, providing a basis for understanding their pathogenesis and identifying potential therapeutic targets.


Assuntos
Fibrose Pulmonar Idiopática , Doenças Pulmonares Intersticiais , Humanos , Transcriptoma , Doenças Pulmonares Intersticiais/genética , Fibrose Pulmonar Idiopática/genética , Fibrose , Perfilação da Expressão Gênica
14.
ACS Appl Mater Interfaces ; 16(13): 16309-16316, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38507679

RESUMO

Constructing highly active and noble metal-free electrocatalysts is significant for the anodic oxygen evolution reaction (OER). Herein, uniform carbon-coated CoP nanospheres (CoP/C) are developed by a direct impregnation coupling phosphorization approach. Importantly, CoP/C only takes a small overpotential of 230 mV at the current density of 10 mA cm-2 and displays a Tafel slope of 56.87 mV dec-1. Furthermore, the intrinsic activity of CoP/C is 21.44 times better than that of commercial RuO2 under an overpotential of 260 mV. In situ Raman spectroscopy studies revealed that a large number of generated Co-O and Co-OH species could facilitate the *OH adsorption, effectively accelerating the reaction kinetics. Meanwhile, the carbon shell with a large number of mesoporous pores acts as the chainmail of CoP, which could improve the active surface area of the catalyst and prevent the Co sites from oxidative dissolution. This work provides a facile and effective reference for the development of highly active and stable OER catalysts.

15.
iScience ; 27(5): 109793, 2024 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-38736547

RESUMO

Vesicular fusion plays a pivotal role in cellular processes, involving stages like vesicle trafficking, fusion pore formation, content release, and membrane integration or separation. This dynamic process is regulated by a complex interplay of protein assemblies, osmotic forces, and membrane tension, which together maintain a mechanical equilibrium within the cell. Changes in cellular mechanics or external pressures prompt adjustments in this equilibrium, highlighting the system's adaptability. This review delves into the synergy between intracellular proteins, structural components, and external forces in facilitating vesicular fusion and release. It also explores how cells respond to mechanical stress, maintaining equilibrium and offering insights into vesicle fusion mechanisms and the development of neurological disorders.

16.
Viruses ; 16(2)2024 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-38399960

RESUMO

Over the last three years, the pandemic of COVID-19 has had a significant impact on people's lives and the global economy. The incessant emergence of variant strains has compounded the challenges associated with the management of COVID-19. As the predominant variant from late 2021 to the present, Omicron and its sublineages, through continuous evolution, have demonstrated iterative viral fitness. The comprehensive elucidation of the biological implications that catalyzed this evolution remains incomplete. In accordance with extant research evidence, we provide a comprehensive review of subvariants of Omicron, delineating alterations in immune evasion, cellular infectivity, and the cross-species transmission potential. This review seeks to clarify the underpinnings of biology within the evolution of SARS-CoV-2, thereby providing a foundation for strategic considerations in the post-pandemic era of COVID-19.


Assuntos
COVID-19 , Humanos , SARS-CoV-2/genética , Exercício Físico , Evasão da Resposta Imune , Glicoproteína da Espícula de Coronavírus
17.
Biomed Opt Express ; 15(6): 3574-3585, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38867780

RESUMO

Super-resolution microscopy has emerged as an indispensable methodology for probing the intricacies of cellular biology. Structured illumination microscopy (SIM), in particular, offers an advantageous balance of spatial and temporal resolution, allowing for visualizing cellular processes with minimal disruption to biological specimens. However, the broader adoption of SIM remains hampered by the complexity of instrumentation and alignment. Here, we introduce speckle-illumination super-resolution microscopy using hydrogel diffusers (hydroSIM). The study utilizes the high scattering and optical transmissive properties of hydrogel materials and realizes a remarkably simplified approach to plug-in super-resolution imaging via a common epi-fluorescence platform. We demonstrate the hydroSIM system using various phantom and biological samples, and the results exhibited effective 3D resolution doubling, optical sectioning, and high contrast. We foresee hydroSIM, a cost-effective, biocompatible, and user-accessible super-resolution methodology, to significantly advance a wide range of biomedical imaging and applications.

18.
PeerJ ; 12: e17663, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39035157

RESUMO

Background: The species composition of and changes in grassland communities are important indices for inferring the number, quality and community succession of grasslands, and accurate monitoring is the foundation for evaluating, protecting, and utilizing grassland resources. Remote sensing technology provides a reliable and powerful approach for measuring regional terrain information, and the identification of grassland species by remote sensing will improve the quality and effectiveness of grassland monitoring. Methods: Ground hyperspectral images of a sericite-Artemisia desert grassland in different seasons were obtained with a Soc710 VP imaging spectrometer. First-order differential processing was used to calculate the characteristic parameters. Analysis of variance was used to extract the main species, namely, Seriphidium transiliense (Poljak), Ceratocarpus arenarius L., Petrosimonia sibirica (Pall), bare land and the spectral characteristic parameters and vegetation indices in different seasons. On this basis, Fisher discriminant analysis was used to divide the samples into a training set and a test set at a ratio of 7:3. The spectral characteristic parameters and vegetation indices were used to identify the three main plants and bare land. Results: The selection of parameters with significant differences (P < 0.05) between the recognition objects effectively distinguished different land features, and the identification parameters also differed due to differences in growth period and species. The overall accuracy of the recognition model established by the vegetation index decreased in the following order: June (98.87%) > September (91.53%) > April (90.37%). The overall accuracy of the recognition model established by the feature parameters decreased in the following order: September (89.77%) > June (88.48%) > April (85.98%). Conclusions: The recognition models based on vegetation indices in different months are superior to those based on feature parameters, with overall accuracies ranging from 1.76% to 9.40% higher. Based on hyperspectral image data, the use of vegetation indices as identification parameters can enable the identification of the main plants in sericite-Artemisia desert grassland, providing a basis for further quantitative classification of the species in community images.


Assuntos
Clima Desértico , Pradaria , Tecnologia de Sensoriamento Remoto/métodos , Imageamento Hiperespectral/métodos , Artemisia/classificação , China , Estações do Ano , Análise Discriminante
19.
RSC Adv ; 14(3): 1909-1923, 2024 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-38192322

RESUMO

Based on the influence of a filamentous laser Gaussian heat source and its movement speed on Polymeric Methyl Methacrylate materials (PMMA sheets), the physical model of heat transfer of PMMA materials by CO2 continuous laser ablation was established. Numerical simulation research on heat transfer in CO2 continuous laser processing of PMMA sheets was carried out by applying the heat transfer model, and experiments on continuous laser processing of PMMA sheets were conducted on the basis of the numerical simulation results. Theoretical and experimental research indicated that under relevant conditions, when the laser power was 20 W, the maximum surface temperature of PMMA sheet was approximately 520 K, which was higher than the melting temperature of the PMMA material, achieving the transformation of the PMMA material from solid to liquid phase in the laser ablation area. When the laser power was 40 W, the CO2 continuous laser could vaporize the PMMA material, cracking the polymer structure of polymethyl methacrylate. When the laser power was 80 W, the maximum surface temperature of the PMMA sheet was approximately 1300 K, and the processing efficiency of CO2 continuous laser ablation of the PMMA material was the highest. The above research provided theoretical guidance and process optimization for the research of CO2 continuous laser ablation of PMMA sheets. The consistency between the experimental results and the numerical simulation results demonstrated the correctness and feasibility of the theoretical model, which has certain universality and reference value for the optimization research of laser processing non-metallic materials and polymer materials.

20.
Sci Rep ; 14(1): 8619, 2024 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-38616200

RESUMO

The joints are existing throughout the underground rock mass. It is of great significance to investigate the shear performance of the rock mass to maintain the stability of the underground structure. In this study, we conducted orthogonal tests to determine the proportion of rock-like materials, and used JRC curves to make specimen molds and then prepare the specimens. We conducted straight shear tests and uniaxial compression tests to determine the various mechanical parameters of the rock-like materials. Next, we carried out the compression and shear tests to investigate the shear characteristics of the specimens, and study the damage pattern and shear strength of the jointed rock mass under different confining pressures and roughness levels. The mesoscopic displacements in the shear process of joints were analyzed by using ABAQUS. The test results show that the effect of the confining pressure on the shear strength of the joint plane is relatively obvious, and a larger confining pressure indicates a larger shear strength. The effects of different joint plane roughness and shear rated on the shear characteristics of the joint plane are also significant. The mesoscopic displacement difference inside the joint plane with higher roughness is relatively large, and the stress concentration phenomenon is obvious and lasts longer, which leads to the faster destruction of the specimen with higher roughness and the higher destruction degree. Therefore, we suggest that the priority should be given to the reinforcement of jointed rock mass with high roughness during the construction to prevent sudden destabilization and failure.

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