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1.
JCI Insight ; 2024 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-39365735

RESUMO

Graves' disease (GD) is an autoimmune condition that can progress to Graves' Ophthalmopathy (GO), leading to irreversible damage to orbital tissues and potential blindness. The pathogenic mechanism is not fully understood. In this study, we conducted single-cell multi-omics analyses on healthy individuals, GD patients without GO, newly diagnosed GO patients, and treated GO patients. Our findings revealed gradual systemic inflammation during GO progression, marked by overactivation of cytotoxic effector T cell subsets, and expansion of specific T cell receptor clones. Importantly, we observed a decline in the immunosuppressive function of activated regulatory T cells (aTreg) accompanied by a cytotoxic phenotypic transition. In vitro experiments revealed that dysfunction and transition of GO-autoreactive Treg were regulated by the yinyang1 (YY1) upon secondary stimulation of thyroid stimulating hormone receptor (TSHR) under inflammatory conditions. Furthermore, adoptive transfer experiments of GO mouse model confirmed infiltration of these cytotoxic Treg into the orbital lesion tissues. Notably, these cells were found to upregulate inflammation and promote pathogenic fibrosis of orbital fibroblasts (OFs). Our results revealed the dynamic changes in immune landscape during GO progression and provided novel insights into the instability and phenotypic transition of Treg, offering potential targets for therapeutic intervention and prevention of autoimmune diseases.

2.
J Am Chem Soc ; 2024 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-39388610

RESUMO

Herein, we report a regiodivergent 1,n-dicarbofunctionalization of unactivated olefins enabled by a Ni-catalyzed radical relay that forges both C(sp3)-C(sp3) and C(sp2)-C(sp3) linkages, even at long-range. Initial studies support an intertwined scenario resulting from the merger of an atom-transfer radical addition (ATRA) and a chain-walking event, with site-selectivity being dictated by a judicious choice of the ligand backbone.

3.
Sci Rep ; 14(1): 23153, 2024 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-39367161

RESUMO

Melatonin supplementation during in vitro maturation (IVM) improves porcine oocyte maturation and embryonic development by exerting antioxidative effects. Nevertheless, the mechanism by which melatonin prevents polyspermy after in vitro fertilization (IVF) remains unclear. Here, we examined the effects of melatonin on cytoplasmic maturation and the incidence of polyspermic penetration in porcine oocytes. No statistically significant difference was observed in the rate of first polar body formation between the groups (Control, Melatonin, Melatonin + Luzindole, and Melatonin + 4-P-PDOT). Interestingly, melatonin supplementation significantly improved the cytoplasmic maturation of porcine oocytes by enhancing the normal distribution of organelles (Golgi apparatus, endoplasmic reticulum and mitochondria) and upregulating organelle-related gene expressions (P < 0.05). However, these promotional effects were counteracted by melatonin antagonists, suggesting that melatonin enhances cytoplasmic maturation through its receptors in porcine oocytes. Melatonin supplementation also significantly improved the rate of diploid and blastocyst formation after IVF by promoting the normal distribution of cortical granules (P < 0.05). In conclusion, melatonin supplementation during in vitro maturation of porcine oocyte improves fertilization efficiency and embryonic developmental competence by enhancing cytoplasmic maturation.


Assuntos
Fertilização in vitro , Melatonina , Oócitos , Receptor MT2 de Melatonina , Animais , Melatonina/farmacologia , Oócitos/efeitos dos fármacos , Oócitos/metabolismo , Suínos , Fertilização in vitro/métodos , Feminino , Receptor MT2 de Melatonina/metabolismo , Receptor MT2 de Melatonina/genética , Técnicas de Maturação in Vitro de Oócitos/métodos , Desenvolvimento Embrionário/efeitos dos fármacos , Fertilização/efeitos dos fármacos , Blastocisto/efeitos dos fármacos , Blastocisto/metabolismo , Triptaminas/farmacologia
4.
Front Microbiol ; 15: 1451582, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39355430

RESUMO

Introduction: Carotenoids are important precursors of various aroma components in tobacco and play an important role in the sensory quality of tobacco. Phaffia rhodozyma is a species of Xanthophyllomyces capable of synthesizing a highly valuable carotenoid-astaxanthin, but has not yet been used in improving tobacco quality. Methods: The dynamic changes of microbial community and metabolites during tobacco fermentation were analyzed in combination with microbiome and metabolome, and the quality of tobacco after fermentation was evaluated by sensory scores. Results: P. rhodozyma could grow and produce carotenoids in tobacco extract, with a maximum biomass of 6.50 g/L and a maximum carotenoid production of 36.13 mg/L at 100 g/L tobacco extract. Meanwhile, the correlation analysis combined with microbiome and metabolomics showed that P. rhodozyma was significantly positively correlated with 11 metabolites such as 6-hydroxyluteolin and quercetin. Furthermore, the contents of alcohols, ketones and esters, which were important aromatic components in fermented tobacco, reached 77.57 µg/g, 58.28 µg/g and 73.51 µg/g, increasing 37.39%, 265.39% and 266.27% compared to the control group, respectively. Therefore, the aroma and flavor, and taste scores of fermented tobacco increased by 0.5 and 1.0 points respectively. Discussion: This study confirmed that P. rhodozyma fermentation could effectively improve the sensory evaluation of tobacco, and provided a novel microbial fermentation method to improve tobacco quality.

5.
Artigo em Inglês | MEDLINE | ID: mdl-39261123

RESUMO

Streptococcus oralis, belonging to the viridans group streptococci (VGS), has been considered a component of the normal flora predominantly inhabiting the oral cavity. In recent years, a growing body of literature has revealed that dental procedures or daily tooth brushing activities can cause the spread of S. oralis from the oral cavity into various body sites leading to life-threatening opportunistic infections such as infective endocarditis (IE) and meningitis. However, very little is currently known about the pathogenicity of S. oralis. Thus, the aim of this review is to update the current understanding of the pathogenic potential of S. oralis to pave the way for the prevention and treatment of S. oralis opportunistic infections.

6.
Gene ; 933: 148919, 2024 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-39236971

RESUMO

Asarum sieboldii Miq. is an important medicinal plant valued for its diverse health benefits in the pharmaceutical industry. In the present study, we isolated and characterized isoeugenol synthase from A. sieboldii (AsIGS), an essential enzyme involved in the biosynthesis of volatile phenylpropenes. We hoped to elucidate the secondary metabolic network of eugenol in A. sieboldii plants, which constructed the prerequisite for quality improvement of the well-known TCM Asari Radix et Rhizoma. Bioinformatics analysis revealed high similarity between the DNA sequences of AsIGS and isoeugenol synthase genes from other plants, and that the association of the candidate protein AsIGS with the PIP reductase family. Moreover, the AsIGS protein displayed a molecular weight of about 34.96 kDa, with a theoretical isoelectric point of 6.01 and an average hydrophobicity of -0.092, indicating the protein's partial acidity, stability, and hydrophilic nature. Phylogenetic analysis showed that AsIGS had a close relationship with isoeugenol synthases and fewer eugenol synthases found in other species. Alphafold2 predicted the structure of the AsIGS protein, and CB-Dock2 predicted the binding sites of the ASIGS-NADPH-coniferyl acetate ternary complex. In vitro enzymatic assay results demonstrated that the optimal temperature of the AsIGS-involved catalysis for coniferyl acetate was 30 °C, and several kinetics parameters were Km (12.21 mM), Vmax (27.9 U/mg), kcat (76.26 s-1), and kcat/Km (6.49 s-1·mM-1). Furthermore, it was also determined that the AsIGS protein had varying performance at different pH levels. While the candidate protein converted coniferyl acetate into both isoeugenol and eugenol at pH 5.5, it just catalyzed the production of isoeugenol at pH 6.5. However, isoeugenol has never been detected in A. sieboldii. Altering AsIGS expression in transgenic plants impacted only eugenol contents. Compared with wild type, overexpression of AsIGS increased eugenol content by 23.3 %, while RNAi-induced down-regulation of AsIGS decreased it by 25.3 %. Taken together, these results confirmed that the AsIGS gene was involved in the biosynthesis of eugenol in A. sieboldii with a dual catalytic potential.

8.
J Biol Chem ; : 107788, 2024 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-39303914

RESUMO

The incidence of germinal center B-cell-like type diffuse large B-cell lymphoma (GCB DLBCL) is steadily increasing, with a known hereditary component. Although some molecular mechanisms in GCB DLBCL have been elucidated, understanding remains incomplete, limiting the effectiveness of targeted therapies. In GCB DLBCL patients, abnormally high expression of zeste homologs 2 (EZH2) is noted, and the compensatory effect of EZH1 following EZH2 inhibition contributes to poor prognosis. This highlights the potential of dual targeting of EZH1/2 as a promising strategy. In this study, we developed a novel inhibitor, EZH-1-P2, targeting EZH1/2, and evaluated its anti-tumor effects on DLBCL cells. Mechanistically, inhibition of EZH1/2 affects the epigenetic regulation of gene expression related to p53, impacting cell cycle progression and GCB DLBCL cell growth. Additionally, while EZH1/2 inhibition impacts NOTCH signaling, the precise mechanism by which it affects M2-type tumor-associated macrophage (M2-TAM) polarization and germinal center expansion requires further investigation. Our research introduces EZH-1-P2 as a novel inhibitor with potential as a candidate for GCB DLBCL therapy, although further studies are needed to fully elucidate its mechanisms.

9.
Heliyon ; 10(16): e35832, 2024 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-39224367

RESUMO

Background: Lung cancer is a highly prevalent malignancy with significant morbidity and mortality rates. MiR-489-3p, a microRNA, has been identified as a regulator of tumor cell proliferation and invasion. Its expression is downregulated in non-small cell lung cancer (NSCLC). Elucidating the molecular mechanisms underlying miR-489-3p's role in NSCLC pathogenesis is crucial for identifying potential diagnostic and therapeutic targets. Methods: To investigate the molecular mechanism of miR-489-3p in NSCLC, this study utilized A549, a commonly used NSCLC cell line. MiR-489-3p mimics and inhibitors were transfected into A549 cells. Additionally, co-transfection experiments using wortmannin, an inhibitor of the PI3K/AKT pathway, were performed. Expression of miR-489-3p and related proteins was analyzed by Western blotting and quantitative real-time PCR (qRT-PCR). Cell migration and proliferation were assessed by wound healing and colony formation assays, respectively. Results: Overexpression of miR-489-3p significantly inhibited the proliferation and migration of A549 cells. This inhibitory effect was further enhanced upon co-transfected with wortmannin. Analysis of human lung specimens showed increased expression of HER2, PI3K, and AKT in lung adenocarcinoma tissues compared to adjacent non-cancerous tissues. Conclusions: These findings suggest that miR-489-3p overexpression may inhibit NSCLC cell proliferation and migration by suppressing the HER2/PI3K/AKT/Snail signaling pathway. This study elucidates miR-489-3p's molecular mechanisms in NSCLC and provides experimental basis for identifying early diagnostic markers and novel therapeutic targets.

10.
Front Public Health ; 12: 1400236, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39319295

RESUMO

Background: Our study was designed to determine the incidence and risk factors of severe acute high-altitude illness (AHAI) in healthy adults first entering the northern Tibetan Plateau of over 5,000 m. Methods: In our prospective observational study, we enrolled 500 people who were scheduled for fast ascension to the northern Tibetan Plateau. The primary outcome variable was severe AHAI, defined as the presence of serious symptoms that could not be ameliorated by general treatment and required evacuation to lower altitudes. According to the inclusion and exclusion criteria, a cohort of 383 healthy people was included in the statistical analysis. We calculated the incidence of severe AHAI, identified the risk factors, and the differences in the most severe symptoms experienced. Results: Sixty-eight people were diagnosed with severe AHAI, and the incidence was 17.8%. Compared to individuals without severe AHAI, those with severe AHAI were more likely to be over the age of 40 years, of Han Chinese nationality, and living at an altitude of <1,500 m. They were less likely to belong to the Yi nationality, had a lower altitude of permanent residence, and exhibited decreased levels of lymphocyte count and hemoglobin concentration. Multivariable logistic regression showed that the mean altitude of permanent residence [per kilometer, adjusted odds ratio (AOR) = 0.464; 95% confidence interval (CI), 0.304-0.708; p < 0.001] and lymphocyte count (AOR = 0.606; 95% CI, 0.378-0.970; p = 0.037) were the independent risk factors. Headache and dyspnea ranked in the top two of the most severe symptoms for people with severe AHAI. Conclusion: Living at lower altitudes and having a decreased lymphocyte level were the risk factors of severe AHAI in healthy adults first entering the plateau of over 5,000 m.


Assuntos
Doença da Altitude , Altitude , Humanos , Masculino , Fatores de Risco , Feminino , Adulto , Incidência , Estudos Prospectivos , Doença da Altitude/epidemiologia , Tibet/epidemiologia , Pessoa de Meia-Idade
11.
Medicine (Baltimore) ; 103(22): e38212, 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-39259130

RESUMO

BACKGROUND: We investigated the current state of frailty in elderly patients with tuberculosis and analyzed the factors that influence it. METHODS: Using a convenience sampling method, 120 elderly patients with tuberculosis were selected from the Department of Infectious Diseases at Lishui Hospital of Traditional Chinese Medicine in Zhejiang Province. A cross-sectional survey was conducted using general demographic questionnaires, the FRAIL (fatigue, resistance, aerobic capacity, illnesses, and loss of weight) screening scale, the self-rating depression scale (SDS), and a questionnaire on respiratory function exercise adherence. The influencing factors for depression were analyzed using logistic regression. RESULTS: The average depression score of the 120 elderly patients with frailty and tuberculosis was 54.88 ± 5.61, indicating a mild level of depression. The correlation between this score and respiratory function exercise adherence was negative. According to a logistic regression analysis, marital status and payment methods were influencing factors for depression in these elderly patients with frailty and tuberculosis. CONCLUSION: There is a need to increase respiratory function exercise adherence among elderly patients with frailty and tuberculosis who have a high incidence of depression. Medical staff should assess adverse emotions in patients and their adherence to respiratory function exercises on a periodic basis.


Assuntos
Depressão , Idoso Fragilizado , Humanos , Estudos Transversais , Masculino , Idoso , Feminino , Depressão/epidemiologia , Depressão/psicologia , Idoso Fragilizado/psicologia , Idoso Fragilizado/estatística & dados numéricos , Cooperação do Paciente/estatística & dados numéricos , Cooperação do Paciente/psicologia , Idoso de 80 Anos ou mais , Tuberculose/psicologia , Pessoa de Meia-Idade , Fragilidade/psicologia , China/epidemiologia , Inquéritos e Questionários
12.
Invest Ophthalmol Vis Sci ; 65(11): 43, 2024 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-39330987

RESUMO

Purpose: Corneal wounding healing is critical for maintaining clear vision, however, a complete understanding of its dynamic regulatory mechanisms remains elusive. Here, we used single-cell RNA sequencing (scRNA-seq) to analyze the cellular activities and transcriptional changes of corneal limbal epithelial cells at different stages after wound healing in cynomolgus monkeys, which exhibit a closer transcriptomic similarity to humans. Methods: Corneal limbal tissues were collected during uninjured, 1-day and 3-day healing stages, dissociated into single cells, and subjected to scRNA-seq using the 10× Genomics platform. Cell types were clustered by graph-based visualization methods and unbiased computational analysis. Additionally, cell migration assays and immunofluorescent staining were performed on cultured human corneal epithelial cells. Results: We characterized nine cell clusters by scRNA-seq analysis of the cynomolgus monkey corneal epithelium. By comparing heterogeneous transcriptional changes in major cell types during corneal healing, we highlighted the importance of limbal epithelial cells (LEPCs) and basal epithelial cells (BEPCs) in extracellular matrix (ECM) formation and wound healing, as well as suprabasal epithelial cells (SEPCs) in epithelial differentiation during the healing processes. We further identified five different sub-clusters in LEPC, including the transit amplifying cell (TAC) sub-cluster that promotes early healing through the activation of thrombospondin-1 (THBS1) expression. Conclusions: Our study represents the first comprehensive exploration of the detailed transcriptome profile of individual corneal cells during the wound healing process in nonhuman primates. We demonstrate the intricate mechanisms involved in corneal healing and provide a promising avenue for potential therapies in corneal wound healing.


Assuntos
Epitélio Corneano , Macaca fascicularis , Análise de Célula Única , Transcriptoma , Cicatrização , Animais , Cicatrização/fisiologia , Cicatrização/genética , Epitélio Corneano/metabolismo , Lesões da Córnea/metabolismo , Lesões da Córnea/genética , Movimento Celular/fisiologia , Perfilação da Expressão Gênica , Células Cultivadas , Modelos Animais de Doenças , Humanos , Limbo da Córnea/citologia , Limbo da Córnea/metabolismo , Masculino
13.
Genes (Basel) ; 15(9)2024 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-39336816

RESUMO

Background: RT-qPCR is a powerful strategy for recognizing the most appropriate reference genes, which can successfully minimize experimental mistakes through accurate normalization. Ludisia discolor, recognized for its ornamental value, features little, distinctive blossoms with twisted lips and gynostemium showing chiral asymmetry, together with striking blood-red fallen leaves periodically marked with golden blood vessels. Methods and Results: To ensure the accuracy of qRT-PCR, selecting appropriate reference genes for quantifying target gene expression levels is essential. This study aims to identify stable reference genes during the development of L. discolor. In this study, the entire floral buds, including the lips and gynostemium from different development stages, were taken as materials. Based upon the transcriptome information of L. discolor, nine housekeeping genes, ACT, HIS, EF1-α1, EF1-α2, PP2A, UBQ1, UBQ2, UBQ3, and TUB, were selected in this research study as prospect interior referral genes. The expression of these nine genes were found by RT-qPCR and afterwards comprehensively examined by four software options: geNorm, NormFinder, BestKeeper, and ΔCt. The outcomes of the analysis showed that ACT was the most steady gene, which could be the most effective inner referral gene for the expression evaluation of flower advancement in L. discolor. Conclusions: The results of this study will contribute to the molecular biology research of flower development in L. discolor and closely related species.


Assuntos
Flores , Regulação da Expressão Gênica de Plantas , Flores/genética , Flores/crescimento & desenvolvimento , Genes de Plantas , Perfilação da Expressão Gênica/métodos , Genes Essenciais/genética , Padrões de Referência , Reação em Cadeia da Polimerase em Tempo Real/normas , Reação em Cadeia da Polimerase em Tempo Real/métodos , Transcriptoma/genética , Proteínas de Plantas/genética
14.
Front Pharmacol ; 15: 1451452, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39323629

RESUMO

Tyrosinase is a key enzyme in melanin synthesis, and its natural inhibitors are receiving increasing attention. Rosa × damascena Herrm. essential oil (RDEO), as important functional metabolites, was widely known due to its biological activities. But its tyrosinase inhibitory activity has not been detailed investigated. Therefore, in this paper, RDEO was comprehensively investigated the tyrosinase inhibitory, followed by the phytochemical composition analysis. Activity screening results showed that RDEO exhibited effective anti-tyrosinase activity and was a reversible and mixed-type inhibitor. CD assay results revealed that RDEO could affect the conformation of tyrosinase to reduce the activity. In B16F10 cells, RDEO (25-100 µg/mL) could inhibit intracellular tyrosinase activity and decrease melanin content. Finally, GC-MS analysis of RDEO found that citronellol (21.22%), geraniol (14.1%), eicosane (11.03%), heneicosane (6.65%) and 1-nonadecene (5.16%) were its main phytochemical compositions. This study provided data support for Rosa × damascena Herrm. essential oil as one potential natural tyrosinase inhibitor and its applications in cosmetics and medicine.

15.
J Org Chem ; 89(17): 12619-12627, 2024 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-39150317

RESUMO

An electrochemical synthesis of vinyl, alkyl, and allyl sulfones using sodium sulfinates and olefins was reported. This method uses direct current to pass through an undivided cell equipped with graphite carbon electrodes, and a series of diverse sulfone compounds can be synthesized at room temperature in high yields.

16.
Water Res ; 265: 122320, 2024 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-39197392

RESUMO

The efficient capture of uranium from wastewater is crucial for environmental remediation and the sustainable development of nuclear energy, yet it poses considerable challenges. In this study, amphiphilic ionic covalent organic framework intercalated into graphene oxide (GO) nanosheets functionalized with polyethyleneimine (PEI) were used to construct hybrid membranes with ultrafast uranium adsorption. These hybrid membranes achieved equilibrium in just 10 min and the adsorption capacity was as high as 358.8 mg g-1 at pH = 6. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) analyses revealed that the strong interaction between sulfonic acid groups and uranyl ions was the primary reason for the high adsorption capacity and selectivity. The extended transition state and natural orbitals for chemical valence (ETS-NOCV) analysis revealed that the interaction between the 7 s and 5f orbitals of uranyl and the 2p orbitals of S and O in the sulfonate was the primary reason for the strong interaction between the sulfonate and the uranyl ion. This research presents an effective method for the rapid extraction of uranium from wastewater.


Assuntos
Grafite , Urânio , Águas Residuárias , Urânio/química , Grafite/química , Águas Residuárias/química , Adsorção , Espectroscopia Fotoeletrônica , Membranas Artificiais , Estruturas Metalorgânicas/química , Poluentes Radioativos da Água/química
17.
J Environ Manage ; 368: 122137, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39153319

RESUMO

Global warming is altering the frequency of extreme rainfall events and introducing uncertainties for non-point source pollution (NPSP). This research centers on orchard-influenced planting areas (OIPA) in the Wulong River Watershed of Shandong Province, China, which are known for their heightened nitrogen (N) and phosphorus (P) pollution. Leveraging meteorological data from both historical (1989-2018) and projected future periods (2041-2100), this research identified five extreme rainfall indices (ERI): R10 (moderate rain), R20 (heavy rain), R50 (rainstorm), R95p (Daily rainfall between the 95th and 99th percentile of the rainfall), and R99p (>99th percentile). Utilizing an advanced watershed hydrological model, SWAT-CO2, this study carried out a comparison between ERI and average conditions and evaluated the effects of ERI on the hydrology and nutrient losses in this coastal watershed. The findings revealed that the growth multiples of precipitation in the OIPA for five ERI varied between 16 and 59 times for the historical period and 14 to 65 times for future climate scenarios compared to the average conditions. The most pronounced increases in surface runoff and total phosphorus (TP) loss were observed with R50, R95p, and R99p, showing growth multiples as high as 352 and 330 times, and total nitrogen (TN) growth multiples varied between 4.6 and 30.3 times. The contribution rates of R50 and R99p for surface runoff and TP loss in the OIPA during all periods exceeded 55%, however, TN exhibited the opposite trend, primarily due to the dominated NO3-N leaching in the sandy soil. This research revealed how the OIPA reacts to different ERI and pinpointed essential elements influencing water and nutrient losses.


Assuntos
Hidrologia , Nitrogênio , Fósforo , Chuva , Fósforo/análise , Nitrogênio/análise , Nutrientes/análise , China , Rios/química , Monitoramento Ambiental
19.
Sci Total Environ ; 950: 175260, 2024 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-39127219

RESUMO

Soil moisture plays an important role in the water and heat exchanges between the land surface and atmosphere, and it has great importance for agricultural production, ecological planning, and water resources management. Although microwave remote sensing has been widely used in large-scale soil moisture monitoring, the accuracy of the downscaled retrieval results cannot be guaranteed for regions with high vegetation coverage and high soil heterogeneity. To address these challenges, this study built soil moisture indice set based on MODIS and elevation data by calculating the Pearson correlation coefficient (R) and Maximum Information Coefficient (MIC), then constructed decision tree models (Gradient Boosting Decision Tree and Random Forest) about the indice set and low-resolution Soil Moisture Active Passive (SMAP) by using two ensemble learning methods (Bagging and Boosting). The models were applied to the high-resolution soil moisture indices in Jilin Province for the years 2017 to 2020 to generate 1 km-resolution products. In the validation process, Triple Collocation Analysis (TCA), comparison of soil moisture maps with coarse and fine resolution, and in-situ measurements in Lishu County, Tongyu County, and Jilin City were used to evaluate the differences between downscaling soil moisture results and ground observations at network, seasonal and point scales. The results were as follows: (1) The correlation coefficient (R2) calculated by the TCA method was 0.733 (GBDT_36km) > 0.649 (RF_36km), and the error variance was 0.0004 (GBDT_36km) < 0.00058 (RF_36km). (2) R at network scale was 0.798 (GBDT_SM) > 0.662 (RF_SM), RMSE was 0.040 (GBDT_SM) < 0.044 (RF_SM), the point scale R was 0.864 (GBDT_SM) > 0.833 (RF_SM), RMSE was 0.029 (GBDT_SM) < 0.039 (RF_SM). The R in four stages of the growth period was GBDT_SM > RF_SM, RMSE was GBDT_SM < RF_SM. In conclusion, the GBDT and RF models can reliably downscale soil moisture in Jilin Province, and the Boosting ensemble learning method represented by GBDT had a better estimation performance.

20.
Math Biosci Eng ; 21(6): 6289-6335, 2024 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-39176427

RESUMO

Hyperparameter optimization (HPO) has been well-developed and evolved into a well-established research topic over the decades. With the success and wide application of deep learning, HPO has garnered increased attention, particularly within the realm of machine learning model training and inference. The primary objective is to mitigate the challenges associated with manual hyperparameter tuning, which can be ad-hoc, reliant on human expertise, and consequently hinders reproducibility while inflating deployment costs. Recognizing the growing significance of HPO, this paper surveyed classical HPO methods, approaches for accelerating the optimization process, HPO in an online setting (dynamic algorithm configuration, DAC), and when there is more than one objective to optimize (multi-objective HPO). Acceleration strategies were categorized into multi-fidelity, bandit-based, and early stopping; DAC algorithms encompassed gradient-based, population-based, and reinforcement learning-based methods; multi-objective HPO can be approached via scalarization, metaheuristics, and model-based algorithms tailored for multi-objective situation. A tabulated overview of popular frameworks and tools for HPO was provided, catering to the interests of practitioners.

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