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1.
Adv Sci (Weinh) ; : e2404094, 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38973354

RESUMO

Nonlinear nanophotonic devices have shown great potential for on-chip information processing, quantum source, 3D microfabrication, greatly promoting the developments of integrated optics, quantum science, nanoscience and technologies, etc. To promote the applications of nonlinear nanodevices, improving the nonlinear efficiency, expanding the spectra region of nonlinear response and reducing device thickness are three key issues. Herein, this study focuses on the nonlinear effect of third-harmonic generation (THG), and present a thin Si meta-sructure to improve the THG efficiency in the ultraviolet (UV) region. The measured THG efficiency is up to 10-5 at an emission wavelength of 309 nm. Also, the THG nanosystem is only 100 nm in thickness, which is two-five times thinner than previous all-dielectric nanosystems applied in THG studies. These findings not only present a powerful thin meta-structure with highly efficient THG emission in UV region, but also provide a constructive avenue for further understanding the light-matter interactions at subwavelength scales, guiding the design and fabricating of advanced photonic devices in future.

2.
Pediatr Pulmonol ; 2024 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-38869182

RESUMO

BACKGROUND: Plastic bronchitis (PB) is a clinical-pathological syndrome characterized by the abnormal accumulation of endogenous substances in the bronchial airways, causing partial or complete obstruction and resulting in impaired lung ventilation. METHODS: In this retrospective analysis, we aim to summarize the clinical manifestations, imaging characteristics, diagnostic methods, and treatment approaches to enhance clinicians' ability to detect children who are infected with human bocavirus 1 (hBoV 1) and develop PB. RESULTS: In the period from January 2021 to January 2024, a total of six hBoV 1 infection children were diagnosed with PB through bronchoscopy. The onset of the condition was mainly concentrated between June and December. The detection methods used included metagenomic next-generation sequencing for pathogen identification (three cases) and respiratory pathogen nucleic acid 13-plex detection (oropharyngeal swab) (three cases), both of which confirmed the presence of hBoV 1. Out of the six children with PB, two were girls and four were boys. Their ages ranged from 10 months to 4 years old. Common symptoms reported by all patients included fever, cough, and wheezing. Chest high-resolution computed tomography scans revealed atelectasis in six cases, in addition to pneumonia. After the removal of the plastic bronchi via bronchoscopy, the airway obstruction symptoms in the children were relieved, and no recurrence was observed during the follow-up period. Pathological findings indicated cellulose exudation and inflammatory cell infiltration, consistent with nonlymphatic PB. CONCLUSION: When children infected with hBoV 1 exhibit persistent or worsening symptoms such as cough, fever, and wheezing despite treatment, clinicians should remain highly vigilant for the potential occurrence of PB. Bronchoscopy plays a crucial role not only in diagnosing the presence of a plastic bronchus but also in effectively treating PB.

3.
Light Sci Appl ; 13(1): 98, 2024 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-38678015

RESUMO

Due to its unbounded and orthogonal modes, the orbital angular momentum (OAM) is regarded as a key optical degree of freedom (DoF) for future information processing with ultra-high capacity and speed. Although the manipulation of OAM based on metasurfaces has brought about great achievements in various fields, such manipulation currently remains at single-DoF level, which means the multiplexed manipulation of OAM with other optical DoFs is still lacking, greatly hampering the application of OAM beams and advancement of metasurfaces. In order to overcome this challenge, we propose the idea of multiplexed coherent pixel (MCP) for metasurfaces. This approach enables the manipulation of arbitrary complex-amplitude under incident lights of both plane and OAM waves, on the basis of which we have realized the multiplexed DoF control of OAM and wavelength. As a result, the MCP method expands the types of incident lights which can be simultaneously responded by metasurfaces, enriches the information processing capability of metasurfaces, and creates applications of information encryption and OAM demultiplexer. Our findings not only provide means for the design of high-security and high-capacity metasurfaces, but also raise the control and application level of OAM, offering great potential for multifunctional nanophotonic devices in the future.

4.
Front Biosci (Landmark Ed) ; 29(1): 37, 2024 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-38287823

RESUMO

Human health is seriously endangered by spontaneous intracerebral hemorrhage (ICH) and aneurysmal subarachnoid hemorrhage (aSAH). Because the majority of ICH and aSAH survivors experience disability, increased risk of stroke recurrence, cognitive decline, and systemic vascular disease, ICH and aSAH assume special importance in neurological disease. Early detection and prediction of neurological function and understanding of etiology and correction are the basis of successful treatment. ICH and aSAH cause complex inflammatory cascades in the brain. In order to establish precise staging and prognosis, as well as provide a basis for treatment selection and monitoring, it is imperative to determine appropriate biological markers according to pathological and physiological mechanisms. In this review, we focus on the research progress of S100B, an endogenous danger signaling molecule, as a potential biomarker for ICH and aSAH, assisting in the development of further basic research and clinical translational studies.


Assuntos
Acidente Vascular Cerebral , Hemorragia Subaracnóidea , Humanos , Hemorragia Cerebral , Fatores de Risco , Biomarcadores , Subunidade beta da Proteína Ligante de Cálcio S100
5.
CNS Neurosci Ther ; 30(4): e14465, 2024 04.
Artigo em Inglês | MEDLINE | ID: mdl-37830163

RESUMO

PURPOSES: To identify potent DNA methylation candidates that could predict response to temozolomide (TMZ) in glioblastomas (GBMs) that do not have glioma-CpGs island methylator phenotype (G-CIMP) but have an unmethylated promoter of O-6-methylguanine-DNA methyltransferase (unMGMT). METHODS: The discovery-validation approach was planned incorporating a series of G-CIMP-/unMGMT GBM cohorts with DNA methylation microarray data and clinical information, to construct multi-CpG prediction models. Different bioinformatic and experimental analyses were performed for biological exploration. RESULTS: By analyzing discovery sets with radiotherapy (RT) plus TMZ versus RT alone, we identified a panel of 64 TMZ efficacy-related CpGs, from which a 10-CpG risk signature was further constructed. Both the 64-CpG panel and the 10-CpG risk signature were validated showing significant correlations with overall survival of G-CIMP-/unMGMT GBMs when treated with RT/TMZ, rather than RT alone. The 10-CpG risk signature was further observed for aiding TMZ choice by distinguishing differential outcomes to RT/TMZ versus RT within each risk subgroup. Functional studies on GPR81, the gene harboring one of the 10 CpGs, indicated its distinct impacts on TMZ resistance in GBM cells, which may be dependent on the status of MGMT expression. CONCLUSIONS: The 64 TMZ efficacy-related CpGs and in particular the 10-CpG risk signature may serve as promising predictive biomarker candidates for guiding optimal usage of TMZ in G-CIMP-/unMGMT GBMs.


Assuntos
Neoplasias Encefálicas , Glioblastoma , Glioma , Humanos , Glioblastoma/tratamento farmacológico , Glioblastoma/genética , Metilação de DNA , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/radioterapia , Temozolomida/farmacologia , Temozolomida/uso terapêutico , Glioma/genética , Metilases de Modificação do DNA/genética , Fenótipo , Antineoplásicos Alquilantes/farmacologia , Antineoplásicos Alquilantes/uso terapêutico , Proteínas Supressoras de Tumor/genética , Enzimas Reparadoras do DNA/genética
6.
Nano Lett ; 23(23): 10991-10997, 2023 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-38018700

RESUMO

Imaging polarimeters find many critical applications in applications ranging from remote sensing to biological detection. Metasurfaces have been proposed as a compact approach for imaging polarimeters, but prior strategies suffer from low imaging resolution. Here, we propose an interleaved metalens configuration for polarization imaging where three-row metasurface units within a group individually interact with three pairs of orthogonal polarization channels. The optical paths between the object and adjacent three-row metasurfaces are nearly equal, allowing the construction of a metalens polarimeter with an unlimited numerical aperture (NA), which is beneficial for high-resolution polarization imaging. The metalens polarimeter fabricated by crystalline silicon nanostructures has a NA of 0.51 at 632.8 nm and achieves an imaging resolution of up to a 1.2-fold wavelength. Polarimetric microscopy experiments demonstrate that metalens polarimeters can realize high-resolution polarization imaging for various microscopic samples. This study offers a promising solution for high-resolution metasurface polarization imaging, with the potential for widespread applications.

7.
J Tradit Complement Med ; 13(6): 538-549, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38020547

RESUMO

Background and aim: Xianglian Wan (XLW) as a classic prescription of traditional Chinese medicine protects digestive function; however, few studies have investigated its anti-colorectal cancer effects. This study verified that the effective monomer berberine of XLW plays an antitumo r role by regulating the acetyl-CoA carboxylase (ACC)/fatty acid synthase (FASN) lipid metabolism-related signaling pathway. Experimental procedure: The connection between XLW and FASN was identified through literature mining, bioinformatics and structural biology. In vivo experiments verified the rationality of the antitumor effect of berberine by regulating the ACC/FASN pathway, and in vitro experiments verified the regulatory relationship between berberine and FASN. Results and conclusion: The most frequent Chinese medicine component in XLW was Coptis chinensis. Berberine, the active ingredient of XLW, has a FASN binding site. FASN expression is higher in tumor tissues than in normal tissues. FASN is related to colorectal adenocarcinoma occurrence and patient survival time. Experiments showed that XLW, berberine and orlistat (FASN inhibitor) can cooperate with palmitic acid (PA) to inhibit tumors in mice. Berberine can downregulate FASN and ACC expression in tumor tissues and inhibit the increase in acetyl-CoA, the intermediate product of exogenous PA intake. The mechanism by which berberine inhibits colon cancer cell proliferation by lowering lipids is related to its downregulation of FASN protein expression. The ACC/FASN signaling pathway is a critical pathway through which berberine, the effective monomer of XLW, plays an antitumor role in colon cancer.

8.
Biomed Pharmacother ; 169: 115876, 2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-37976888

RESUMO

Long non-coding RNAs (lncRNAs) are a type of RNAs that are more than 200 nucleotides without protein-coding potential. In recent years, more and more attention has been paid to the role of lncRNAs in cancer pathogenesis. LncRNA KCNQ1 overlapping transcript 1 (KCNQ1OT1) is located on chromosome 11p15.5 with a total length of 91 kb and is highly expressed in various malignancies, which is closely related to tumor growth, lymph node metastasis, survival cycle and recurrence rate. In addition, KCNQ1OT1 is involved in the regulation of PI3K/AKT and Wnt/ß-catenin signaling pathways. In this review, the mechanism and related progress of KCNQ1OT1 in different cancers were reviewed. It was found that KCNQ1OT1 can stabilize mRNA expression through sponging miRNA, which not only induced tumor cell proliferation, migration, invasion, drug resistance, epithelial-mesenchymal transition (EMT) and inhibited cell apoptosis in vitro, but also promoted tumor growth and metastasis in vivo. Therefore, as a new biomarker and therapeutic target, KCNQ1OT1 has broad prospects for the diagnosis and treatment of different cancers.


Assuntos
MicroRNAs , Neoplasias , RNA Longo não Codificante , Humanos , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Neoplasias/genética , Proliferação de Células/genética , Regulação Neoplásica da Expressão Gênica , Linhagem Celular Tumoral
9.
Heliyon ; 9(6): e16937, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37484257

RESUMO

Objectives: This study aimed to determine whether SII on different days of admission is associated with severity and 180-day functional outcomes after basal ganglia ICH. Methods: In this retrospective study, data on baseline CT imaging characteristics, mRS, hematoma volume, and laboratory variables were included. The SII and NLR, LMR, and PLR were calculated from laboratory data collected on admission day, day 1, and days 5-7. Both univariate and multivariable logistic regression analyses were used to assess the association between the SII and the outcome. The receiver operating characteristic (ROC) analysis and area under the curve (AUC) were also used to evaluate the ability of the SII to predict outcomes. Result: A total of 245 patients were enrolled in the study. On different days, the NLR, PLR, and SII were significantly lower in patients with favorable outcomes than in those with poor outcomes, and the volume of hemorrhage was positively correlated with the SII. These parameters were associated with outcomes in the univariate logistic regression. In the adjusted analyses, the SII and PLR were independent predictors of basal ganglia ICH outcomes. ROC analysis revealed that the SII showed a stronger ability to predict the 6-month outcomes of patients after basal ganglia ICH than the PLR on different days (AUC = 0.642, 0.804, 0.827 vs. 0.592, 0.725, 0.757; all P < 0.001). Conclusion: The SII independently and strongly predicts the outcome of basal ganglia ICH. A high SII was associated with poor 6-month outcomes in patients with basal ganglia ICH.

10.
J Tradit Chin Med ; 43(3): 514-522, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37147753

RESUMO

OBJECTIVE: To evaluate the therapeutic efficacy and the influence on cerebral blood supply of waggle needling Yanglingquan (GB34) on spastic paresis (SP) rats after middle cerebral artery occlusion (MCAO) induced and investigate its mechanism of relieving neurobehavior deficiency. METHODS: SP rat model was produced by permanent MCAO. Rats were divided into five groups: blank control group (Control), sham operation group (Sham), model group (Model), waggle needling group (WN) and perpendicular needling group (PN). SP rats were treated with acupuncture from day 3 after MCAO, once a day for 6 d. The modified neurological severity score (mNSS) and modified Ashworth scale (MAS) were conducted on days 0, 1, 3, 5, 7 and 9. Cerebral blood flow (CBF) in ischemic cortex was measured by laser speckle imaging 5 min pre ischemia, 5 min post ischemia, and after intervention on day 9. All rats were sacrificed at day 9 and the protein and mRNA expressions of γ2 subunit of the γ-aminobutyric acid receptor A (GABAAγ2) and K+-Cl?cotransporter 2 (KCC2) in the ischemic cortex and lumber enlargement was measured by Western blotting and real-time quantitative polymerase chain reaction. RESULTS: Both Control and Sham groups showed no changes in mNSS and MAS scores and in the regional CBF. Compared with Model group, both WN and PN treatments significantly ameliorated neurological deficit ( 0.01), decreased muscle tone ( 0.05), and enhanced CBF ( 0.001) in SP rats; moreover, WN showed superior effects than PN ( 0.001). In line with the improvement in neurobehavior, acupuncture interventions up-regulated the expressions of GABAAγ2 and KCC2 in the ischemic cortex as well as lumber enlargement ( 0.01) in SP rats, and those changes were more obvious in WN ( 0.05). CONCLUSIONS: Acupuncture at Yanglingquan (GB34) enhanced cerebral blood flow and ameliorated SP in permanent MCAO rats, while waggle needling was superior to regular perpendicular needling. Waggle needling Yanglingquan (GB34) would be a potential complementary therapy for SP.


Assuntos
Terapia por Acupuntura , Isquemia Encefálica , Ratos , Animais , Infarto da Artéria Cerebral Média/terapia , Isquemia Encefálica/genética , Isquemia Encefálica/terapia , Ratos Sprague-Dawley , Nylons , Espasticidade Muscular , Circulação Cerebrovascular , Suturas
11.
Opt Express ; 31(6): 9376-9386, 2023 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-37157509

RESUMO

Employing nanostructure to generate large chiroptical response has been cultivated as an emerging field, for its great potentials in integrated optics, biochemistry detections, etc. However, the lack of intuitive approaches for analytically describing the chiroptical nanoparticles has discouraged researchers from effectively designing advanced chiroptical structures. In this work, we take the twisted nanorod dimer system as a basic example to provide an analytical approach from the perspective of mode coupling, including far-field coupling and near-field coupling of nanoparticles. Using this approach, we can calculate the expression of circular dichroism (CD) in the twisted nanorod dimer system, which can establish the analytical relationship between the chiroptical response and the basic parameters of this system. Our results show that the CD response can be engineered by modulating the structure parameters, and a high CD response of ∼ 0.78 under the guidance of this approach has been achieved.

12.
Front Pharmacol ; 14: 1139201, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36937857

RESUMO

In recent years, natural polysaccharides have attracted more and more attention and research because of their value in the medicine, beauty and food fields. Salvia miltiorrhiza is a traditional Chinese herb that has been used for thousands of years and has antidiabetic, antifibrotic, neuroprotective, antioxidation, anti-inflammatory and other effects. It mainly includes rosmarinic acid, tanshinone I, tanshinone IIA, tanshinone IIB, procatechualdehyde, polysaccharide and salvianolic acids. Salvia miltiorrhiza polysaccharide is a polysaccharide extracted and isolated from Salvia miltiorrhiza and has diverse biological functions, including antioxidation, anti-tumor, hepatoprotective, anti-inflammatory, immune regulatory and cardioprotective effect. In this review, the extraction, purification, structural characterization and biological activity of SMPs are summarized and new perspectives for the future work of SMPs were also proposed, we hope our research can provide a reference for further research on SMPs.

13.
Environ Pollut ; 323: 121295, 2023 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-36822311

RESUMO

Tropical forests, where the soils are nitrogen (N) rich but phosphorus (P) poor, have a disproportionate influence on global carbon (C) and N cycling. While N deposition substantially alters soil C and N retention in tropical forests, whether P input can alleviate these N-induced effects by regulating soil microbial functions remains unclear. We investigated soil microbial taxonomy and functional traits in response to 10-year independent and interactive effects of N and P additions in a primary and a secondary tropical forest in Hainan Island. In the primary forest, N addition boosted oligotrophic bacteria and phosphatase and enriched genes responsible for C-, P-mineralization, nitrification and denitrification, suggesting aggravated P limitation while N excess. This might stimulate P excavation via organic matter mineralization, and enhance N losses, thereby increasing soil CO2 and N2O emissions by 86% and 110%, respectively. Phosphorus and NP additions elevated C-mining enzymes activity mainly due to intensified C limitation, causing 82% increase in CO2 emission. In secondary forest, P and NP additions reduced phosphatase activity, enriched fungal copiotrophs and increased microbial biomass, suggesting removal of nutrient deficiencies and stimulation of fungal growth. Meanwhile, soil CO2 emission decreased by 25% and N2O emission declined by 52-82% due to alleviated P acquisition from organic matter decomposition and increased microbial C and N immobilization. Overall, N addition accelerates most microbial processes for C and N release in tropical forests. Long-term P addition increases C and N retention via reducing soil CO2 and N2O emissions in the secondary but not primary forest because of strong C limitation to microbial N immobilization. Further, the seasonal and annual variations in CO2 and N2O emissions should be considered in future studies to test the generalization of these findings and predict and model dynamics in greenhouse gas emissions and C and N cycling.


Assuntos
Dióxido de Carbono , Solo , Dióxido de Carbono/farmacologia , Dióxido de Carbono/análise , Microbiologia do Solo , Fósforo , Florestas , Nitrogênio/farmacologia , Óxido Nitroso/análise
14.
Appl Opt ; 62(4): 1096-1102, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36821169

RESUMO

Herein, a low-frequency broadband multilayer metamaterial absorber (MMA) based on resistive frequency selective surfaces (RFSSs) is proposed, which consists of a three-layer RFSS, three-layer polymethacrylimide (PMI) foam substrates, and a copper film. The proposed absorber has the advantages of ultra-broadband absorption with absorptivity more than 90% ranging from 1.91 to 20.78 GHz, which covers the entire S, C, X, and Ku bands with the thickness of 0.102λ L (where λ L corresponds to the wavelength of the lowest operating frequency). The absorption performance can keep good stability in a wide angular range for both TE and TM modes. Moreover, a prototype of the proposed MMA is fabricated and experimentally measured to demonstrate its excellent performance. The experimental results show excellent consistency with numerical simulations.

15.
Sci Total Environ ; 854: 158709, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36126705

RESUMO

Microorganisms govern soil nutrient cycling. It is therefore critical to understand their responses to human-induced increases in N and P inputs. We investigated microbial community composition, biomass, functional gene abundance, and enzyme activities in response to 10-year N and P addition in a primary tropical montane forest, and we explored the drivers behind these effects. Fungi were more sensitive to nutrient addition than bacteria, and the fungal community shift was mainly driven by P availability. N addition aggravated P limitation, to which microbes responded by increasing the abundance of P cycling functional genes and phosphatase activity. In contrast, P addition alleviated P deficiency, and thus P cycling functional gene abundance and phosphatase activity decreased. The shift of microbial community composition, changes in functional genes involved in P cycling, and phosphatase activity were mainly driven by P addition, which also induced the alteration of soil stoichiometry (C/P and N/P). Eliminating P deficiency through fertilization accelerated C cycling by increasing the activity of C degradation enzymes. The abundances of C and P functional genes were positively correlated, indicating the intensive coupling of C and P cycling in P-limited forest soil. In summary, a long-term fertilization experiment demonstrated that soil microorganisms could adapt to induced environmental changes in soil nutrient stoichiometry, not only through shifts of microbial community composition and functional gene abundances, but also through the regulation of enzyme production. The response of the microbial community to N and P imbalance and effects of the microbial community on soil nutrient cycling should be incorporated into the ecosystem biogeochemical model.


Assuntos
Microbiota , Nitrogênio , Humanos , Nitrogênio/análise , Solo/química , Fósforo/metabolismo , Microbiologia do Solo , Florestas , Fertilização , Monoéster Fosfórico Hidrolases , Carbono/metabolismo
16.
Med Biol Eng Comput ; 61(1): 109-127, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36327009

RESUMO

This paper proposes a novel color medical image encryption method based on mean shift algorithm and fractional-order hyperchaotic system. Firstly, color medical images were divided into lesion area, detection area, and edge area by using mean shift clustering. Low-value pixels and zero-value pixels in the edge region are abandoned to improve the encryption efficiency. Secondly, the doctor-patient information is embedded into the pixel matrix of the lesion region by using discrete wavelet transform and singular value decomposition. Thirdly, the pixels of the lesion region and the detection region are processed by using fractional-order hyperchaotic system. Finally, the color medical image embedded with doctor-patient information can be quickly encrypted. Security analysis shows that the encryption method has not only strong robustness and security, but also good performance against various attacks. SPNA and CA results: (a) s1-DE-SPNA, (b) s2-DE-SPNA, (c) s3-DE-SPNA, (d) s4-DE-SPNA; (e) s1-DE-CA, (f) s2-DE-CA, (g) s3-DE-CA, (h) s4-DE-CA.


Assuntos
Segurança Computacional , Processamento de Imagem Assistida por Computador , Humanos , Processamento de Imagem Assistida por Computador/métodos , Algoritmos , Análise de Ondaletas
17.
Light Sci Appl ; 11(1): 302, 2022 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-36253356

RESUMO

Polarization as an important degree of freedom for light plays a key role in optics. Structured beams with controlled polarization profiles have diverse applications, such as information encoding, display, medical and biological imaging, and manipulation of microparticles. However, conventional polarization optics can only realize two-dimensional polarization structures in a transverse plane. The emergent ultrathin optical devices consisting of planar nanostructures, so-called metasurfaces, have shown much promise for polarization manipulation. Here we propose and experimentally demonstrate color-selective three-dimensional (3D) polarization structures with a single metasurface. The geometric metasurfaces are designed based on color and phase multiplexing and polarization rotation, creating various 3D polarization knots. Remarkably, different 3D polarization knots in the same observation region can be achieved by controlling the incident wavelengths, providing unprecedented polarization control with color information in 3D space. Our research findings may be of interest to many practical applications such as vector beam generation, virtual reality, volumetric displays, security, and anti-counterfeiting.

18.
ACS Appl Mater Interfaces ; 14(42): 47542-47548, 2022 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-36228176

RESUMO

Precise adjustment of the metal site structure in single-atom catalysts (SACs) plays a key role in addressing the oxygen evolution reaction (OER). Herein, we report the synthesis of O-doped Ni SACs anchored on porous graphene-like carbon (Ni-O-G) using molten salts (ZnCl2 and NaCl) as templates, in which the unique Ni-O4 structure serves as the active sites. Ni-O-G, with an overpotential of only 238 mV (@ 10 mA cm-2), is one of the more advanced catalysts. An array of characterizations and density functional theory calculations show that the Ni-O4 coordination enables Ni to be closer to the Fermi level compared to traditional Ni-N4, enhancing the electronic metal-support interaction to facilitate OER kinetics. Thus, this work offers an alternative strategy for the structural modulation of Ni SACs and the effect of different coordination elements with the same atomic coordination structure on the intrinsic OER activity.

19.
Artigo em Inglês | MEDLINE | ID: mdl-36034948

RESUMO

Rhizoma Atractylodes macrocephala polysaccharide (RAMP), the main bioactive compound extracted from Rhizoma Atractylodes macrocephala (RAM), exhibits various biological activities in in vivo and in vitro methods, such as anti-inflammatory, antioxidant, antitumor, immunomodulatory, hepatoprotective effects, and other functions. This review systematically summarizes the recent research progress on the extraction, purification, structural characteristics, and biological activities of RAMP. We hope to provide a theoretical basis for further research on the application of RAMP in the fields of biomedicine and food.

20.
Front Plant Sci ; 13: 942851, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35991414

RESUMO

Elucidating the effects of atmospheric nitrogen (N) deposition on the photosynthetic capacity of plants is critical to understand forest growth and conservation under global change. However, studies on this topic generally consider only understory N addition, which ignores the effect of canopy interception. In this study, we conducted a field experiment in a subtropical forest to compare the effects of canopy vs. understory N addition on the photosynthetic rate of canopy and understory species. We found that canopy N addition enhanced the photosynthetic rate of canopy species by increasing leaf hydraulic conductivity and shortening the distance of CO2 transportation. In contrast, understory N addition had non-significant effects on the photosynthetic rate of canopy species. Moreover, the photosynthetic rate of understory species was not affected by canopy or understory N addition. Interestingly, changes in hydraulic conductivity contributed more to accelerating the photosynthetic rate than changes in CO2 transport distance. Our results provide important insights into the dissimilar effects of canopy and understory N addition on the photosynthetic rates of species in subtropical forests. Based on our findings, we highlighted the urgent need to consider canopy processes in future studies on N deposition.

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