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1.
Nature ; 599(7886): 599-604, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34819685

RESUMO

Amorphous materials inherit short- and medium-range order from the corresponding crystal and thus preserve some of its properties while still exhibiting novel properties1,2. Due to its important applications in technology, amorphous carbon with sp2 or mixed sp2-sp3 hybridization has been explored and prepared3,4, but synthesis of bulk amorphous carbon with sp3 concentration close to 100% remains a challenge. Such materials inherit the short-/medium-range order of diamond and should also inherit its superior properties5. Here, we successfully synthesized millimetre-sized samples-with volumes 103-104 times as large as produced in earlier studies-of transparent, nearly pure sp3 amorphous carbon by heating fullerenes at pressures close to the cage collapse boundary. The material synthesized consists of many randomly oriented clusters with diamond-like short-/medium-range order and possesses the highest hardness (101.9 ± 2.3 GPa), elastic modulus (1,182 ± 40 GPa) and thermal conductivity (26.0 ± 1.3 W m-1 K-1) observed in any known amorphous material. It also exhibits optical bandgaps tunable from 1.85 eV to 2.79 eV. These discoveries contribute to our knowledge about advanced amorphous materials and the synthesis of bulk amorphous materials by high-pressure and high-temperature techniques and may enable new applications for amorphous solids.

2.
Am J Hum Genet ; 107(3): 403-417, 2020 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-32755546

RESUMO

Human Phenotype Ontology (HPO)-based analysis has become standard for genomic diagnostics of rare diseases. Current algorithms use a variety of semantic and statistical approaches to prioritize the typically long lists of genes with candidate pathogenic variants. These algorithms do not provide robust estimates of the strength of the predictions beyond the placement in a ranked list, nor do they provide measures of how much any individual phenotypic observation has contributed to the prioritization result. However, given that the overall success rate of genomic diagnostics is only around 25%-50% or less in many cohorts, a good ranking cannot be taken to imply that the gene or disease at rank one is necessarily a good candidate. Here, we present an approach to genomic diagnostics that exploits the likelihood ratio (LR) framework to provide an estimate of (1) the posttest probability of candidate diagnoses, (2) the LR for each observed HPO phenotype, and (3) the predicted pathogenicity of observed genotypes. LIkelihood Ratio Interpretation of Clinical AbnormaLities (LIRICAL) placed the correct diagnosis within the first three ranks in 92.9% of 384 case reports comprising 262 Mendelian diseases, and the correct diagnosis had a mean posttest probability of 67.3%. Simulations show that LIRICAL is robust to many typically encountered forms of genomic and phenomic noise. In summary, LIRICAL provides accurate, clinically interpretable results for phenotype-driven genomic diagnostics.


Assuntos
Biologia Computacional , Bases de Dados Genéticas , Genômica , Doenças Raras/diagnóstico , Algoritmos , Exoma/genética , Humanos , Fenótipo , Doenças Raras/genética , Software
3.
Soft Matter ; 20(1): 255-265, 2023 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-38086671

RESUMO

It is of great research significance to prepare a new shear thickening fluid (STF) with a simple process, remarkable thickening effect and excellent impact resistance from the properties of the particles. Inspired by the shear thickening mechanism, nano-silica particle clusters (SPC) with different morphological structures were prepared by the reaction of amino-modified silica with polyethylene glycol diglycidyl ether (PEGDGE), and the structure models of particle clusters were designed through theoretical analysis. The structure of SPC was affected by the degree of amination modification and the molecular weight of PEGDGE, which was analyzed by DLS and TEM. The shear thickening behavior of the fluid was evaluated by steady-state rheology and dynamic-state rheology analysis. The shear thickening behavior of the fluid composed of SPC also changed greatly with the influence of the degree of amination modification and the molecular weight of PEGDGE. In addition, compared with the STF contained original silica, the STF contained SPC could produce a faster and stronger shear thickening response. Therefore, silica particle clusters are not only a promising candidate for the preparation of high-performance shear thickening fluids, but can also be better applied to industrial and scientific fields such as impact protection and shock absorption.

4.
Proc Natl Acad Sci U S A ; 117(13): 7090-7094, 2020 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-32179681

RESUMO

Electronic phase separation in complex oxides is the inhomogeneous spatial distribution of electronic phases, involving length scales much larger than those of structural defects or nonuniform distribution of chemical dopants. While experimental efforts focused on phase separation and established its correlation with nonlinear responses under external stimuli, it remains controversial whether phase separation requires quenched disorder for its realization. Early theory predicted that if perfectly "clean" samples could be grown, both phase separation and nonlinearities would be replaced by a bicritical-like phase diagram. Here, using a layer-by-layer superlattice growth technique we fabricate a fully chemically ordered "tricolor" manganite superlattice, and compare its properties with those of isovalent alloyed manganite films. Remarkably, the fully ordered manganite does not exhibit phase separation, while its presence is pronounced in the alloy. This suggests that chemical-doping-induced disorder is crucial to stabilize the potentially useful nonlinear responses of manganites, as theory predicted.

5.
Plant Physiol ; 187(4): 2530-2543, 2021 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-34890460

RESUMO

Several effectors from phytopathogens usually target various cell organelles to interfere with plant defenses, and they generally contain sequences that direct their translocation into organelles, such as chloroplasts. In this study, we characterized a different mechanism for effectors to attack chloroplasts in wheat (Triticum aestivum). Two effectors from Puccinia striiformis f. sp. tritici (Pst), Pst_4, and Pst_5, inhibit Bax-mediated cell death and plant immune responses, such as callose deposition and reactive oxygen species (ROS) accumulation. Gene silencing of the two effectors induced significant resistance to Pst, demonstrating that both effectors function as virulence factors of Pst. Although these two effectors have low sequence similarities and lack chloroplast transit peptides, they both interact with TaISP (wheat cytochrome b6-f complex iron-sulfur subunit, a chloroplast protein encoded by nuclear gene) in the cytoplasm. Silencing of TaISP impaired wheat resistance to avirulent Pst and resulted in less accumulation of ROS. Heterogeneous expression of TaISP enhanced chloroplast-derived ROS accumulation in Nicotiana benthamiana. Co-localization in N. benthamiana and western blot assay of TaISP content in wheat chloroplasts show that both effectors suppressed TaISP from entering chloroplasts. We conclude that these biotrophic fungal effectors suppress plant defenses by disrupting the sorting of chloroplast protein, thereby limiting host ROS accumulation and promoting fungal pathogenicity.


Assuntos
Basidiomycota/fisiologia , Cloroplastos/metabolismo , Doenças das Plantas/microbiologia , Imunidade Vegetal , Proteínas de Plantas/metabolismo , Triticum/imunologia , Transporte Biológico , Resistência à Doença , Triticum/microbiologia
6.
Environ Sci Technol ; 56(11): 7298-7307, 2022 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-35239329

RESUMO

The UK Biobank (UKBB) is a large population-based cohort that provides a unique opportunity to study the association between environmental exposure and biomarkers and to identify biomarkers as potential instruments for assessing exposure dose, health damage, and disease risks. On 462 063 participants of European ancestry, we characterized the relationship of 38 disease-relevant biomarkers, asthma diagnosis, ambient pollution, traffic factors, and genetic background. The air pollutant exposure on the UKBB cohort was fairly low (e.g., mean PM2.5 concentration at 10.0 µg/m3). Nevertheless, 30 biomarkers were in association with at least one environmental factor; e.g., C-reactive protein levels were positively associated with NO (padj = 2.99 × 10-4), NO2 (padj = 4.15 × 10-4), and PM2.5 (padj = 1.92 × 10-6) even after multiple testing adjustment. Asthma diagnosis was associated with four pollutants (NO, NO2, PM2.5, and PM10). The largest effect size was observed in PM2.5, where a 5 µg/m3 increment of exposure was associated with a 1.52 increase in asthma diagnosis (p = 4.41 × 10-13). Further, environmental exposure and genetic predisposition influenced biomarker levels and asthma diagnosis in an additive model. The exposure-biomarker associations identified in this study could serve as potential indicators for environmental exposure induced health damages. Our results also shed light on possible mechanisms whereby environmental exposure influences disease-causing biomarkers and in turn increases disease risk.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Asma , Poluentes Ambientais , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Asma/epidemiologia , Asma/etiologia , Biomarcadores , Exposição Ambiental/análise , Humanos , Dióxido de Nitrogênio , Material Particulado/análise
7.
Nucleic Acids Res ; 48(D1): D704-D715, 2020 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-31701156

RESUMO

In biology and biomedicine, relating phenotypic outcomes with genetic variation and environmental factors remains a challenge: patient phenotypes may not match known diseases, candidate variants may be in genes that haven't been characterized, research organisms may not recapitulate human or veterinary diseases, environmental factors affecting disease outcomes are unknown or undocumented, and many resources must be queried to find potentially significant phenotypic associations. The Monarch Initiative (https://monarchinitiative.org) integrates information on genes, variants, genotypes, phenotypes and diseases in a variety of species, and allows powerful ontology-based search. We develop many widely adopted ontologies that together enable sophisticated computational analysis, mechanistic discovery and diagnostics of Mendelian diseases. Our algorithms and tools are widely used to identify animal models of human disease through phenotypic similarity, for differential diagnostics and to facilitate translational research. Launched in 2015, Monarch has grown with regards to data (new organisms, more sources, better modeling); new API and standards; ontologies (new Mondo unified disease ontology, improvements to ontologies such as HPO and uPheno); user interface (a redesigned website); and community development. Monarch data, algorithms and tools are being used and extended by resources such as GA4GH and NCATS Translator, among others, to aid mechanistic discovery and diagnostics.


Assuntos
Biologia Computacional/métodos , Genótipo , Fenótipo , Algoritmos , Animais , Ontologias Biológicas , Bases de Dados Genéticas , Exoma , Estudos de Associação Genética , Variação Genética , Genômica , Humanos , Internet , Software , Pesquisa Translacional Biomédica , Interface Usuário-Computador
8.
Inorg Chem ; 59(10): 7181-7187, 2020 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-32352295

RESUMO

Lanthanide (such as Tb and Eu) metal-organic frameworks (MOFs) have been widely used in fluorescent probes because of their multiple coordination modes and brilliant fluorescence characteristic. Many lanthanide MOFs were applied in detecting metal ions, inorganic anions, and small molecules. However, it's rarely reported that Ln-MOF was devoted to detecting malachite green (MG) and uric acid (UA). We prepared a europium-based metal-organic framework (Eu-TDA) (TDA = 2,5-thiophenedicarboxylic acid group). Luminescence studies demonstrated that Eu-TDA can rapidly detect MG and UA with excellent selectivity and sensitivity, where individual quenching efficiency Ksv (MG: 5.8 × 105 M-1; UA: 4.15 × 104 M-1) and detection limit (MG: 0.0221 µM; UA: 0.689 µM) were regarded as the excellent MOF sensors for detecting MG and UA. The quenching of Eu-TDA's fluorescence emission by MG and UA was likely due to the spectral overlap, energy transfer, and competition. Among 11 metal cations and 14 anions, Eu-TDA can quickly and effectively recognize MG and UA with highly selective and sensitive properties. Our method possesses potential application in detecting UA in human blood and MG in the fishpond.

9.
Appl Opt ; 59(5): A48-A53, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-32225352

RESUMO

A nitridated Ru/B4C multilayer with period of 3.0 nm and 80 bilayers were fabricated to study thermal and temporal stability. The multilayer was annealed from room temperature to 490°C, and the in situ X-ray measurements showed that the reflectivity remains mostly unchanged up to 300°C. An essential drop of the reflectivity occurred at 490°C with significantly increased interface roughness. A new layered structure with larger thickness than the original multilayer started to appear at 400°C. The nitridated Ru/B4C multilayer remains intact after two years of storage in air, which demonstrated a very good temporal stability.

10.
Inorg Chem ; 57(22): 14396-14400, 2018 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-30378431

RESUMO

TiF3 exhibits a rhombohedral to ReO3-type cubic phase transformation at ∼340 K. Here we report that, by introducing ZrF4 into TiF3, the cubic phase is stabilized at least down to 123 K in the Ti1- xZr xF3+ x compounds. All compounds exhibit low thermal expansion (LTE) between 123 and 623 K, and a nearly zero thermal expansion (ZTE) was obtained in Ti0.7Zr0.3F3.3 (αL = 0.91 ppm/K). The analysis of pair distribution function reveals that the cation-centered octahedra are partially changed to pentagonal bipyramids in Ti1- xZr xF3+ x due to the excess fluorines relative to the case of TiF3. Therefore, the cooperative rotation of the polyhedra tends to be restricted, and the cubic phase is thus stabilized. The restrained polyhedral rotations compete against the lattice softening caused by the introduction of Zr4+, giving rise to the LTE. Our present strategy is applicable to other rhombohedral metal trifluorides for the design of new isotropic ZTE materials.

11.
Front Pharmacol ; 15: 1396641, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38725660

RESUMO

Type 2 diabetes mellitus is regarded as a chronic metabolic disease characterized by hyperglycemia. Long-term hyperglycemia may result in oxidative stress, damage pancreatic ß-cell function and induce insulin resistance. Herein we explored the anti-hypoglycemic effects and mechanisms of action of N-p-coumaroyloctopamine (N-p-CO) in vitro and in vivo. N-p-CO exhibited high antioxidant activity, as indicated by the increased activity of SOD, GSH and GSH-Px in HL-7702 cells induced by both high glucose (HG) and palmitic acid (PA). N-p-CO treatment significantly augmented glucose uptake and glycogen synthesis in HG/PA-treated HL-7702 cells. Moreover, administration of N-p-CO in diabetic mice induced by both high-fat diet (HFD) and streptozotocin (STZ) not only significantly increased the antioxidant levels of GSH-PX, SOD and GSH, but also dramatically alleviated hyperglycemia and hepatic glucose metabolism in a dose-dependent manner. More importantly, N-p-CO upregulated the expressions of PI3K, AKT and GSK3ß proteins in both HG/PA-induced HL-7702 cells and HFD/STZ-induced mice. These findings clearly suggest that N-p-CO exerts anti-hypoglycemic and anti-oxidant effects, most probably via the regulation of a PI3K/AKT/GSK3ß signaling pathway. Thus, N-p-CO may have high potentials as a new candidate for the prevention and treatment of diabetes.

12.
Front Pharmacol ; 15: 1392338, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38966547

RESUMO

Introduction: Alcohol consumption alters the diversity and metabolic activities of gut microbiota, leading to intestinal barrier dysfunction and contributing to the development of alcoholic liver disease (ALD), which is the most prevalent cause of advanced liver diseases. In this study, we investigated the protective effects and action mechanism of an aqueous extraction of Pericarpium citri reticulatae and Amomi fructus (PFE) on alcoholic liver injury. Methods: C57BL/6 mice were used to establish the mouse model of alcoholic liver injury and orally administered 500 and 1,000 mg/kg/d of PFE for 2 weeks. Histopathology, immunohistochemistry, immunofluorescence, Western blotting, qRT-PCR, and 16S rDNA amplicon sequencing were used to analyze the mechanism of action of PFE in the treatment of alcohol-induced liver injury. Results: Treatment with PFE significantly improved alcohol-induced liver injury, as illustrated by the normalization of serum alanine aminotransferase, aspartate aminotransferase, total triglyceride, and cholesterol levels in ALD mice in a dose-dependent manner. Administration of PFE not only maintained the intestinal barrier integrity prominently by upregulating mucous production and tight junction protein expressions but also sensibly reversed the dysregulation of intestinal microecology in alcohol-treated mice. Furthermore, PFE treatment significantly reduced hepatic lipopolysaccharide (LPS) and attenuated oxidative stress as well as inflammation related to the TLR4/NF-κB signaling pathway. The PFE supplementation also significantly promoted the production of short-chain fatty acids (SCFAs) in the ALD mice. Conclusion: Administration of PFE effectively prevents alcohol-induced liver injury and may also regulate the LPS-involved gut-liver axis; this could provide valuable insights for the development of drugs to prevent and treat ALD.

13.
Nanomicro Lett ; 16(1): 79, 2024 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-38189993

RESUMO

Black phosphorus with a superior theoretical capacity (2596 mAh g-1) and high conductivity is regarded as one of the powerful candidates for lithium-ion battery (LIB) anode materials, whereas the severe volume expansion and sluggish kinetics still impede its applications in LIBs. By contrast, the exfoliated two-dimensional phosphorene owns negligible volume variation, and its intrinsic piezoelectricity is considered to be beneficial to the Li-ion transfer kinetics, while its positive influence has not been discussed yet. Herein, a phosphorene/MXene heterostructure-textured nanopiezocomposite is proposed with even phosphorene distribution and enhanced piezo-electrochemical coupling as an applicable free-standing asymmetric membrane electrode beyond the skin effect for enhanced Li-ion storage. The experimental and simulation analysis reveals that the embedded phosphorene nanosheets not only provide abundant active sites for Li-ions, but also endow the nanocomposite with favorable piezoelectricity, thus promoting the Li-ion transfer kinetics by generating the piezoelectric field serving as an extra accelerator. By waltzing with the MXene framework, the optimized electrode exhibits enhanced kinetics and stability, achieving stable cycling performances for 1,000 cycles at 2 A g-1, and delivering a high reversible capacity of 524 mAh g-1 at - 20 â„ƒ, indicating the positive influence of the structural merits of self-assembled nanopiezocomposites on promoting stability and kinetics.

14.
Nat Commun ; 15(1): 8029, 2024 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-39271666

RESUMO

The genetic factors of stroke in South Asians are largely unexplored. Exome-wide sequencing and association analysis (ExWAS) in 75 K Pakistanis identified NM_000435.3(NOTCH3):c.3691 C > T, encoding the missense amino acid substitution p.Arg1231Cys, enriched in South Asians (alternate allele frequency = 0.58% compared to 0.019% in Western Europeans), and associated with subcortical hemorrhagic stroke [odds ratio (OR) = 3.39, 95% confidence interval (CI) = [2.26, 5.10], p = 3.87 × 10-9), and all strokes (OR [CI] = 2.30 [1.77, 3.01], p = 7.79 × 10-10). NOTCH3 p.Arg231Cys was strongly associated with white matter hyperintensity on MRI in United Kingdom Biobank (UKB) participants (effect [95% CI] in SD units = 1.1 [0.61, 1.5], p = 3.0 × 10-6). The variant is attributable for approximately 2.0% of hemorrhagic strokes and 1.1% of all strokes in South Asians. These findings highlight the value of diversity in genetic studies and have major implications for genomic medicine and therapeutic development in South Asian populations.


Assuntos
Predisposição Genética para Doença , Receptor Notch3 , Acidente Vascular Cerebral , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Sequenciamento do Exoma , Frequência do Gene , Imageamento por Ressonância Magnética , Mutação de Sentido Incorreto , Paquistão/etnologia , Polimorfismo de Nucleotídeo Único , Receptor Notch3/genética , População do Sul da Ásia/genética , Acidente Vascular Cerebral/genética , Reino Unido/epidemiologia , Biobanco do Reino Unido
15.
Bioorg Med Chem Lett ; 23(10): 2863-7, 2013 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-23587425
16.
Environ Sci Pollut Res Int ; 30(19): 54694-54722, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36879091

RESUMO

In 2011, aiming to achieve sustainable development in the transportation sector, the Chinese government started a pilot policy of low-carbon transportation system (LCTS). Based on the panel data for 280 prefecture-level cities in China from 2006 to 2017, we first measure carbon efficiency by using the SBM-DEA model, and identify the direct and spatial spillover effects of LCTS on carbon efficiency and carbon intensity by adopting a spatial difference-in-differences approach (SDID). The results indicate that LCTS construction not only enhances local carbon performance but also has a significant spatial spillover effect in neighboring cities. The results are still valid after a series of robustness tests. The mechanism analysis reveals that LCTS can elevate carbon performance by improving energy efficiency, green innovation, and developing public transit. The direct and indirect effects of LCTS on carbon performance show more pronounced effects in megalopolis and eastern region. This paper provides reliable empirical evidence for the effect of LCTS on carbon performance, which is conducive to deepening the understanding of carbon emissions and has a high reference value for the rational formulation of carbon reduction policies.


Assuntos
Pegada de Carbono , Carbono , Cidades , Política Pública , Desenvolvimento Sustentável , Meios de Transporte , Dióxido de Carbono , China , Desenvolvimento Econômico , Monitoramento Ambiental , Projetos Piloto , Políticas
17.
Ann Oper Res ; : 1-29, 2023 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-37361057

RESUMO

Accurate carbon price forecasting can better allocate carbon emissions and thus ensure a balance between economic development and potential climate impacts. In this paper, we propose a new two-stage framework based on processes of decomposition and re-estimation to forecast prices across international carbon markets. We focus on the Emissions Trading System (ETS) in the EU, as well as the five main pilot schemes in China, spanning the period from May 2014 to January 2022. In this way, the raw carbon prices are first separated into multiple sub-factors and then reconstructed into factors of 'trend' and 'period' with the use of Singular Spectrum Analysis (SSA). Once the subsequences have been thus decomposed, we further apply six machine learning and deep learning methods, allowing the data to be assembled and thus facilitating the prediction of the final carbon price values. We find that from amongst these machine learning models, the Support vector regression (SSA-SVR) and Least squares support vector regression (SSA-LSSVR) stand out in terms of performance for the prediction of carbon prices in both the European ETS and equivalent models in China. Another interesting finding to come out of our experiments is that the sophisticated algorithms are far from being the best performing models in the prediction of carbon prices. Even after accounting for the impacts of the COVID-19 pandemic and other macro-economic variables, as well as the prices of other energy sources, our framework still works effectively.

18.
Front Psychol ; 14: 1048146, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36818068

RESUMO

Introduction: Since the outbreak of the novel coronavirus pneumonia (COVID-19), China has entered normalization phase of its epidemic prevention and control measures that emphasizes 'precise prevention and control,' 'dynamic zeroing', and 'universal vaccination'. However, medical staff continue to face physical and mental stress. The present study aimed to investigate the job satisfaction of medical staff in China, as well as any associated factors. Methods: 2,258 medical staff completed a questionnaire specially designed for this study. Independent samples t-tests, one-way analysis of variance, and binary logistic regression were used to analyze associated factors. Results: Overall, 48.4% of the participants expressed satisfaction with their job; the highest-scoring dimension was interpersonal relationships (3.83 ± 0.73), while the lowest scoring dimension was salary and benefits (3.13 ± 0.94). The logistic regression model indicated that job satisfaction among medical staff is associated with being aged 40-49 years [odds ratio (OR) = 2.416] or > 50 years (OR = 2.440), having an above-undergraduate education level (OR = 1.857), holding a position other than doctor [i.e., nurse (OR = 3.696) or 'other' (OR = 2.423)], having a higher income (OR = 1.369), and having fewer monthly overtime shifts (OR = 0.735-0.543). Less than half of the medical staff expressed satisfaction with their job, indicating that the overall level is not high. Discussion: This research enriches the study of medical workers' job satisfaction during periods when epidemic prevention and control has become familiar and routine. To improve medical workers' job satisfaction, administrators should seek to enhance medical staff's remuneration, reduce their work pressure, and meet their needs (where reasonable).

19.
Int J Biol Macromol ; 253(Pt 3): 126797, 2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-37703963

RESUMO

The creation of functional components with precise chemistries on carbohydrate polymers is of great significance for future wearable biomedicine and health management. Among various carbohydrate polymers, marine polysaccharide featured with antimicrobial, biodegradable and biocompatible properties is an ideal platform while the water-swelling nature makes it difficult to form stable interface. Here, well-dispersed silver nanoparticles have been in-situ assembled on hydrated alginate fabric (AF), involving chemical absorption of Ag ions and in-situ reduction of conductive Ag layer. Owing to the stable complex formed between Ag ions and carboxyl groups, the Ag-grafted AF exhibits superior Joule heating capability, including low operating voltage (1-3 V), high saturation temperature (63 °C), rapid response time (25 s) and outstanding durability against harsh conditions. Furthermore, the Ag-grafted AF demonstrates noticeable inhibition against E. coli and S. aureus as compared with the pristine AF. This work provides a rational strategy for the functionalization of hydrated polysaccharide and enables wearable thermotherapy devices for human health management.


Assuntos
Nanopartículas Metálicas , Dispositivos Eletrônicos Vestíveis , Humanos , Nanopartículas Metálicas/química , Escherichia coli , Alginatos , Staphylococcus aureus , Prata/química , Polímeros , Íons
20.
Acta Biomater ; 158: 475-492, 2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-36640954

RESUMO

Intervertebral disc degeneration (IVDD) is a degenerative disease characterized by lower-back pain, causing disability globally. Antioxidant therapy is currently considered one of the most promising strategies for IVDD treatment, given the crucial role of reactive oxygen species (ROS) in IVDD pathogenesis. Herein, a ROS-responsive magnesium-containing microsphere (Mg@PLPE MS) was constructed for the antioxidative treatment of IVDD. The Mg@PLPE MS has a core-shell structure comprising poly(lactic-co-glycolic acid) (PLGA) and ROS-responsive polymer poly(PBT-co-EGDM) as the shell and a magnesium microparticle as the core. The poly(PBT-co-EGDM) can be destroyed by H2O2 through the H2O2-triggered hydrophobic-to-hydrophilic transition, subsequently promoting an Mg-water reaction to produce H2. Thus, Mg@PLPE MS provides a valuable platform for H2O2 elimination and controlled H2 release. The generated H2 scavenge for ROS by reacting with noxious •OH. Notably, the Mg@PLPE MS exerted significant antioxidative and anti-inflammatory effects in a disc degeneration rat model and alleviated extracellular matrix degradation and disc cells apoptosis, thereby underlining its efficacy in IVDD treatment. The Mg@PLPE MS also exhibited robust biocompatibility and negligible toxicity, presenting the promise for the antioxidative treatment of IVDD in vivo. STATEMENT OF SIGNIFICANCE: Antioxidant therapy is currently considered one of the most promising strategies for intervertebral disc degeneration (IVDD) treatment, given the crucial role of reactive oxygen species (ROS) in IVDD pathogenesis. Here, ROS-responsive magnesium-containing microspheres (Mg@PLPE MSs) were constructed to alleviate IVDD through controlled release of hydrogen gas. The Mg@PLPE MSs can effectively scavenge overproduced ROS by simultaneously reacting with H2O2 and •OH, thus creating a suitable microenvironment for inhibition of ECM degradation. As a result, Mg@PLPE MSs treated IVDD rats exhibit minimal nucleus pulposus decrease, less extracellular matrix degradation, minimal radial fissure of fibrous rings, and higher disc height index. Therefore, the as-prepared Mg@PLPE MSs may shed a new light on clinical treatment of IVDD.


Assuntos
Degeneração do Disco Intervertebral , Disco Intervertebral , Núcleo Pulposo , Ratos , Animais , Degeneração do Disco Intervertebral/patologia , Antioxidantes/farmacologia , Antioxidantes/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Ratos Sprague-Dawley , Microesferas , Magnésio/metabolismo , Peróxido de Hidrogênio/farmacologia , Núcleo Pulposo/patologia , Disco Intervertebral/metabolismo
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