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1.
Nat Mater ; 23(9): 1222-1229, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38906993

RESUMEN

Moiré superlattices have emerged as a new platform for studying strongly correlated quantum phenomena, but these systems have been largely limited to van der Waals layer two-dimensional materials. Here we introduce moiré superlattices leveraging ultrathin, ligand-free halide perovskites, facilitated by ionic interactions. Square moiré superlattices with varying periodic lengths are clearly visualized through high-resolution transmission electron microscopy. Twist-angle-dependent transient photoluminescence microscopy and electrical characterizations indicate the emergence of localized bright excitons and trapped charge carriers near a twist angle of ~10°. The localized excitons are accompanied by enhanced exciton emission, attributed to an increased oscillator strength by a theoretically predicted flat band. This research showcases the promise of two-dimensional perovskites as unique room-temperature moiré materials.

2.
J Am Chem Soc ; 146(3): 2187-2195, 2024 Jan 24.
Artículo en Inglés | MEDLINE | ID: mdl-38216555

RESUMEN

In recent years, optical pump-probe microscopy (PPM) has become a vital technique for spatiotemporally imaging electronic excitations and charge-carrier transport in metals and semiconductors. However, existing methods are limited by mechanical delay lines with a probe time window up to several nanoseconds (ns) or monochromatic pump and probe sources with restricted spectral coverage and temporal resolution, hindering their amenability in studying relatively slow processes. To bridge these gaps, we introduce a dual-hyperspectral PPM setup with a time window spanning from nanoseconds to milliseconds and single-nanosecond resolution. Our method features a wide-field probe tunable from 370 to 1000 nm and a pump spanning from 330 nm to 16 µm. We apply this PPM technique to study various two-dimensional metal-halide perovskites (2D-MHPs) as representative semiconductors by imaging their transient responses near the exciton resonances under both above-band gap electronic pump excitation and below-band gap vibrational pump excitation. The resulting spatially and temporally resolved images reveal insights into heat dissipation, film uniformity, distribution of impurity phases, and film-substrate interfaces. In addition, the single-nanosecond temporal resolution enables the imaging of in-plane strain wave propagation in 2D-MHP single crystals. Our method, which offers extensive spectral tunability and significantly improved time resolution, opens new possibilities for the imaging of charge carriers, heat, and transient phase transformation processes, particularly in materials with spatially varying composition, strain, crystalline structure, and interfaces.

3.
J Am Chem Soc ; 146(40): 27861-27870, 2024 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-39327910

RESUMEN

The synthesis of extremely thin 2D halide perovskites and the exploration of their interlayer interactions have garnered significant attention in current research. A recent advancement we have made involves the development of a successful technique for generating ultrathin MAPbI3 nanosheets with controlled thickness and an exposed intrinsic surface. This innovative method relies on utilizing the Ruddlesden-Popper (RP) phase perovskite (BA2MAn-1PbnI3n+1) as a template. However, the precise reaction mechanism remains incompletely understood. In this work, we systematically examined the dynamic evolution of the phase conversion process, with a specific focus on the influence of inorganic slab (composed of [PbI6]4- octahedrons) numbers on regulating the thickness and quality of the resulting MAPbI3 nanosheets. Additionally, the atomic structure is directly visualized using the transmission electron microscopy (TEM) method, confirming its exceptional quality. To illustrate interfacial interactions in ultrathin structures, artificial moiré superlattices are constructed through a physical transfer approach, revealing multiple localized high-symmetry stacks within a distinctive square moiré pattern. These findings establish a novel framework for investigating the physics of interfacial interactions in ionic semiconducting crystals.

4.
Postgrad Med J ; 100(1186): 603-610, 2024 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-38521977

RESUMEN

OBJECTIVE: To investigate the associations of tea, coffee, and red wine intakes with health risks among individuals with hypertension. METHODS: This prospective cohort study included participants with hypertension from the UK Biobank cohort. Study exposures included self-reported intakes of coffee, tea, and red wine. The primary outcome was all-cause mortality, and the secondary outcomes were cardiovascular mortality and cardiovascular disease. The associations of beverage intake with outcomes were analyzed using Cox regression models. The hazard ratios and 95% confidence intervals were estimated. RESULTS: A total of 187 708 participants with hypertension were included. The median follow-up period was 13.8 years. In individuals with hypertension, drinking one to two cups/day of coffee or three to four cups/day of tea was significantly associated with the lowest risk of all-cause mortality compared with less than one cup/day [hazard ratio for coffee, 0.943 (95% confidence interval, 0.908-0.979); hazard ratio for tea, 0.882 (95% confidence interval, 0.841-0.924)]. Red wine intake was inversely associated with all-cause mortality risk. Dose-response analysis revealed that high coffee intake (approximately greater than or equal to six cups/day) was significantly associated with increased risks of cardiovascular mortality and cardiovascular disease, but high tea and red wine intakes were not. Furthermore, replacing plain water with tea, but not coffee, significantly reduced the risks of all-cause mortality and cardiovascular disease. Replacing other alcoholic beverages with red wine also significantly reduced the risks of all three outcomes. CONCLUSIONS: These findings suggest that tea and red wine, but not coffee, can be part of a healthy diet for the hypertensive population.


Asunto(s)
Enfermedades Cardiovasculares , Café , Hipertensión , , Vino , Humanos , Masculino , Femenino , Persona de Mediana Edad , Estudios Prospectivos , Enfermedades Cardiovasculares/prevención & control , Enfermedades Cardiovasculares/mortalidad , Reino Unido/epidemiología , Anciano , Modelos de Riesgos Proporcionales , Factores de Riesgo , Adulto
5.
J Am Chem Soc ; 145(36): 19885-19893, 2023 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-37651697

RESUMEN

Epitaxial heterostructures of two-dimensional (2D) halide perovskites offer a new platform for studying intriguing structural, optical, and electronic properties. However, difficulties with the stability of Pb- and Sn-based heterostructures have repeatedly slowed the progress. Recently, Pb-free halide double perovskites are gaining a lot of attention due to their superior stability and greater chemical diversity, but they have not been successfully incorporated into epitaxial heterostructures for further investigation. Here, we report epitaxial core-shell heterostructures via growing Pb-free double perovskites (involving combinations of Ag(I)-Bi(III), Ag-Sb, Ag-In, Na-Bi, Na-Sb, and Na-In) around Pb perovskite 2D crystals. Distinct from Pb-Pb and Pb-Sn perovskite heterostructures, growths of the Pb-free shell at 45° on the (100) surface of the lead perovskite core are observed in all Pb-free cases. The in-depth structural analysis carried out with electron diffraction unequivocally demonstrates the growth of the Pb-free shell along the [110] direction of the Pb perovskite, which is likely due to the relatively lower surface energy of the (110) surface. Furthermore, an investigation of anionic interdiffusion across heterostructure interfaces under the influence of heat was carried out. Interestingly, halide anion diffusion in the Pb-free 2D perovskites is found to be significantly suppressed as compared to Pb-based 2D perovskites. The great structural tunability and excellent stability of Pb-free perovskite heterostructures may find uses in electronic and optoelectronic devices in the near future.

6.
Small ; 19(6): e2205540, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36461727

RESUMEN

Solid catalyst is widely recognized as an effective strategy to control the chirality of single-walled carbon nanotubes (SWNTs). However, it is still not compatible with high density in horizontal arrays. "Trojan" catalysts strategy is one of the most effective methods to realize SWNTs with high density and has great potential in chirality control. Here, the co-realization of high density and chirality controlling for SWNTs in a low-temperature growth process is reported based on the developed solid "Trojan" catalyst. High temperature "Trojan" catalyst formation process provides sufficient catalyst number to acquire high density. These liquid "Trojan" catalysts are cooled to solid state by adopting low growth temperature (540 °C), which can be good template to realize the chirality controlling of SWNTs with exposing six-fold symmetry face, (111). Finally, (9, 6) and (13, 1) SWNTs enriched horizontal array with the purity of ≈90% and density of 4 tubes µm-1 is realized. The comparison between the distribution of initial catalysts and the density of as-grown tubes indicates no sacrificing on catalysts number to improve chirality selectivity. This work opens a new avenue on the catalyst's design and chirality controlling in SWNTs growth.

7.
Nature ; 543(7644): 234-238, 2017 03 09.
Artículo en Inglés | MEDLINE | ID: mdl-28199307

RESUMEN

The semiconductor industry is increasingly of the view that Moore's law-which predicts the biennial doubling of the number of transistors per microprocessor chip-is nearing its end. Consequently, the pursuit of alternative semiconducting materials for nanoelectronic devices, including single-walled carbon nanotubes (SWNTs), continues. Arrays of horizontal nanotubes are particularly appealing for technological applications because they optimize current output. However, the direct growth of horizontal SWNT arrays with controlled chirality, that would enable the arrays to be adapted for a wider range of applications and ensure the uniformity of the fabricated devices, has not yet been achieved. Here we show that horizontal SWNT arrays with predicted chirality can be grown from the surfaces of solid carbide catalysts by controlling the symmetries of the active catalyst surface. We obtained horizontally aligned metallic SWNT arrays with an average density of more than 20 tubes per micrometre in which 90 per cent of the tubes had chiral indices of (12, 6), and semiconducting SWNT arrays with an average density of more than 10 tubes per micrometre in which 80 per cent of the nanotubes had chiral indices of (8, 4). The nanotubes were grown using uniform size Mo2C and WC solid catalysts. Thermodynamically, the SWNT was selectively nucleated by matching its structural symmetry and diameter with those of the catalyst. We grew nanotubes with chiral indices of (2m, m) (where m is a positive integer), the yield of which could be increased by raising the concentration of carbon to maximize the kinetic growth rate in the chemical vapour deposition process. Compared to previously reported methods, such as cloning, seeding and specific-structure-matching growth, our strategy of controlling the thermodynamics and kinetics offers more degrees of freedom, enabling the chirality of as-grown SWNTs in an array to be tuned, and can also be used to predict the growth conditions required to achieve the desired chiralities.

8.
J Ultrasound Med ; 42(4): 797-807, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35730210

RESUMEN

OBJECTIVES: This study aimed to compare the diagnostic accuracy of shear wave elastography (SWE) with that of shear wave dispersion (SWD) in evaluation of hepatic parenchyma in patients with liver tumors before resection. METHODS: A total of 174 patients with liver tumors were prospectively enrolled. SWE and SWD examinations were performed. Fibrosis stage and necroinflammatory activity were determined histopathologically according to the Scheuer standard. We compared the diagnostic accuracy of SWE and SWD. RESULTS: Both SWE and SWD values of the liver were highly correlated with liver fibrosis stage (P < .05, respectively). Both SWE and SWD values of the liver were moderately correlated with necroinflammatory activity (P < .05, respectively). Both SWE and SWD values of the liver were not correlated with steatosis (P > .05, respectively). Both SWE and SWD values were significantly different among the patients with different stages of liver fibrosis (P < .001, respectively). The area under the receiver operating characteristic (ROC) curve of SWE value was 0.982, 0.977, 0.969, and 0.984 for predicting S ≥ 1, S ≥ 2, S ≥ 3, and S = 4, respectively. The optimal cutoff SWE values were 6.9, 7.9, 8.7, and 10.6 kPa for S ≥ 1, S ≥ 2, S ≥ 3, and S = 4, respectively. The area under the ROC curve of SWD value was 0.967, 0.960, 0.925, and 0.954 for predicting S ≥ 1, S ≥ 2, S ≥ 3, and S = 4, respectively. The optimal cutoff SWD values were 11.2, 12.0, 13.2, and 16.0 m/s/kHz for S ≥ 1, S ≥ 2, S ≥ 3, and S = 4, respectively. CONCLUSIONS: SWE and SWD could be noninvasive and accurate for predicting the stage of liver fibrosis in patients with liver tumors before surgery. SWE was more accurate than SWD in predicting severe fibrosis (S ≥ 3) and cirrhosis (S = 4).


Asunto(s)
Diagnóstico por Imagen de Elasticidad , Neoplasias Hepáticas , Humanos , Diagnóstico por Imagen de Elasticidad/métodos , Hígado/diagnóstico por imagen , Hígado/patología , Cirrosis Hepática/diagnóstico por imagen , Cirrosis Hepática/patología , Neoplasias Hepáticas/diagnóstico por imagen , Neoplasias Hepáticas/cirugía , Neoplasias Hepáticas/patología , Fibrosis
9.
J Dairy Sci ; 106(11): 7382-7395, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37641259

RESUMEN

Cow milk is an important source of food protein for children; however, it could lead to allergy, especially for infants. α-Lactalbumin (α-LA) and ß-lactoglobulin (ß-LG) from whey protein make up a relatively high proportion of milk proteins and have received widespread attention as major allergens in milk. However, few studies have identified the epitopes of both proteins simultaneously. In this study, ImmunoCAP and indirect ELISA were first used for detection of sIgE to screen sera from allergic patients with high binding capacity for α-LA and ß-LG. Subsequently, the mimotopes was biopanned by phage display technology and bioinformatics and 17 mimic peptide sequences were obtained. Aligned with the sequences of α-LA or ß-LG, we identified one linear epitope on α-LA at AA 11-26 and 5 linear epitopes on ß-LG at AA 9-29, AA 45-57, AA 77-80, AA 98-101, and AA 121-135, respectively. Meanwhile, the 8 conformational epitopes and their distributions of α-LA and ß-LG were located using the Pepitope Server. Finally, glutamine and lysine were determined as common AA residues for the conformational epitopes both on α-LA and ß-LG. Moreover, we found the addition of mouse anti-human IgE during the biopanning process did not significantly affect the identification of the epitopes.

10.
COPD ; 20(1): 101-108, 2023 12.
Artículo en Inglés | MEDLINE | ID: mdl-36656660

RESUMEN

Chronic obstructive pulmonary disease (COPD) and asthma are chronic inflammatory diseases of the airways. Galectin-13 has recently been forwarded as a biomarker for airway eosinophilic inflammation in asthma. However, the association between galectin-13 and COPD remains unknown. To examine the changes in galectin-13 expression in acute exacerbations of COPD (AECOPD) and the stable phase of COPD and unveil the association between galectin-13 expression and eosinophilic inflammation in COPD, we measured plasma galectin-13 expression in different phases of COPD patients (n = 60, 44 AECOPD patients, and 16 stable COPD patients) and healthy controls (n = 15). Plasma levels of galectin-13 in 60 COPD patients were further analyzed and compared to systemic inflammation, airway eosinophilic inflammation, and lung function. The plasma galectin-13 level was markedly increased in subjects with AECOPD compared to stable COPD patients and healthy controls. Plasma galectin-13 levels in COPD subjects were positively correlated with serum CRP (rs = 0.46, p = 0.0003), peripheral blood eosinophilia count (rs = 0.57, p<0.0001), and FeNO (rs = 0.46, p = 0.0002). In addition, the level of galectin-13 was negatively correlated with FEV1 (rs = -0.43, p = 0.0001), FEV1 pred (%) (rs = -0.544, p<0.0001), as well as FEV1/FVC (rs = -0.46, p<0.0001). Multiple linear regression analysis suggested that plasma galectin-13 levels were affected by FEV1 pred (%), peripheral blood eosinophilia count, and FeNO. We concluded that galectin-13 levels were increased in COPD patients, and elevated galectin-13 expressions related to airway eosinophilic inflammation. Galectin-13 may facilitate the identification of COPD endotypes and may become a potential therapeutic target.


Asunto(s)
Asma , Eosinofilia , Enfermedad Pulmonar Obstructiva Crónica , Humanos , Asma/complicaciones , Inflamación , Galectinas
11.
Chem Rev ; 120(22): 12592-12684, 2020 Nov 25.
Artículo en Inglés | MEDLINE | ID: mdl-33064453

RESUMEN

Single-walled carbon nanotubes (SWNTs) emerge as a promising material to advance carbon nanoelectronics. However, synthesizing or assembling pure metallic/semiconducting SWNTs required for interconnects/integrated circuits, respectively, by a conventional chemical vapor deposition method or by an assembly technique remains challenging. Recent studies have shown significant scientific breakthroughs in controlled SWNT synthesis/assembly and applications in scaled field effect transistors, which are a critical component in functional nanodevices, thereby rendering the horizontal SWNT array an important candidate for innovating nanotechnology. This review provides a comprehensive analysis of the controlled synthesis, surface assembly, characterization techniques, and potential applications of horizontally aligned SWNT arrays. This review begins with the discussion of synthesis of horizontally aligned SWNTs with regulated direction, density, structure, and theoretical models applied to understand the growth results. Several traditional procedures applied for assembling SWNTs on target surface are also briefly discussed. It then discusses the techniques adopted to characterize SWNTs, ranging from electron/probe microscopy to various optical spectroscopy methods. Prototype applications based on the horizontally aligned SWNTs, such as interconnects, field effect transistors, integrated circuits, and even computers, are subsequently described. Finally, this review concludes with challenges and a brief outlook of the future development in this research field.

12.
Postgrad Med J ; 98(1166): 906-913, 2022 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-37063013

RESUMEN

BACKGROUND: Several predictors of COVID-19 severity have been reported. However, chronic airway inflammation characterised by accumulated lymphocytes or eosinophils may affect the pathogenesis of COVID-19. METHODS: In this retrospective cohort study, we reviewed the medical records of all patients with laboratory-confirmed COVID-19 with chronic bronchitis, chronic obstructive pulmonary disease (COPD) and asthma admitted to the Sino-French New City Branch of Tongji Hospital, a large regional hospital in Wuhan, China, from 26 January to 3 April. The Tongji Hospital Ethics Committee approved this study. RESULTS: There were 59 patients with chronic bronchitis, COPD and asthma. When compared with non-severe patients, severe patients were more likely to have decreased lymphocyte counts (0.6×109/L vs 1.1×109/L, p<0.001), eosinopaenia (<0.02×109/L; 73% vs 24%, p<0.001), increased lactate dehydrogenase (LDH) (471.0 U/L vs 230.0 U/L, p<0.001) and elevated interleukin 6 level (47.4 pg/mL vs 5.7 pg/mL, p=0.002) on admission. Eosinopaenia and elevated LDH were significantly associated with disease severity in both univariate and multivariate regression models including the above variables. Moreover, eosinophil count and LDH level tended to return to normal range over time in both groups after treatment and severe patients recovered slower than non-severe patients, especially in eosinophil count. CONCLUSIONS: Eosinopaenia and elevated LDH are potential predictors of disease severity in patients with COVID-19 with underlying chronic airway diseases. In addition, they could indicate disease progression and treatment effectiveness.


Asunto(s)
Asma , Bronquitis Crónica , COVID-19 , Enfermedad Pulmonar Obstructiva Crónica , Humanos , Asma/complicaciones , Bronquitis Crónica/patología , COVID-19/complicaciones , Eosinófilos , Inflamación/patología , Lactato Deshidrogenasas , Estudios Retrospectivos
13.
J Am Soc Nephrol ; 32(10): 2561-2578, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-34479967

RESUMEN

BACKGROUND: IgA nephropathy (IgAN) is the most common primary GN worldwide. Circulating immune complexes form that are prone to deposition in the mesangium, where they trigger glomerular inflammation. A growing body of evidence suggests that dysregulated expression of microRNAs in IgAN may play a significant role in establishing the disease phenotype. METHODS: We generated single miR-23b-3p(miR-23b) knockout mice using CRISPR-Cas9. RESULTS: In humans, miR-23b levels are downregulated in kidney biopsies and sera of patients with IgAN, and serum miR-23b levels are negatively correlated with serum IgA1 levels. We show that miR-23b-/- mice develop an IgAN-like phenotype of mesangial IgA and C3 deposition associated with development of albuminuria, hypertension, an elevated serum creatinine, and dysregulated mucosal IgA synthesis. Dysregulation of IgA production is likely mediated by the loss of miR-23b-mediated suppression of activation-induced cytidine deaminase in mucosal B cells. In addition, we show that loss of miR-23b increases the susceptibility of the kidney to progressive fibrosis through loss of regulation of expression of gremlin 2 and IgA accumulation through downregulation of the transferrin receptor. CONCLUSIONS: Our findings suggest an indispensable role for miR-23b in kidney disease, and in particular, IgAN. miR-23b may in the future offer a novel therapeutic target for the treatment of IgAN.


Asunto(s)
Glomerulonefritis por IGA/genética , Inmunoglobulina A/biosíntesis , Mucosa Intestinal/metabolismo , MicroARNs/genética , Animales , Linfocitos B/enzimología , Proteínas Morfogenéticas Óseas/metabolismo , Células Cultivadas , Complemento C3/metabolismo , Citidina Desaminasa/metabolismo , Citocinas/genética , Regulación hacia Abajo , Activación Enzimática , Femenino , Fibrosis , Mesangio Glomerular/patología , Glomerulonefritis por IGA/patología , Humanos , Hipertensión/genética , Inmunoglobulina A/sangre , Mucosa Intestinal/patología , Masculino , Ratones , Ratones Noqueados , MicroARNs/metabolismo , Fenotipo , Receptores de Transferrina/genética , Transducción de Señal/genética
14.
Diabetologia ; 64(3): 681-692, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33398455

RESUMEN

AIMS/HYPOTHESIS: In a mouse model of diabetic cardiomyopathy (DCM) the expression of the circular RNA circHIPK3 was found to be significantly increased. This study aimed to discover the molecular mechanisms linking circHIPK3 to the pathogenesis of DCM. METHODS: The diabetic mouse model was established by i.p. injection of streptozotocin, which led to the development of DCM. Echocardiographic measurements were used to evaluate cardiac structure and function, and histological staining was applied to detect myocardial fibrosis in mice. 5-Ethynyl-2'-deoxyuridine incorporation was performed to determine cell proliferation and RNA fluorescent in situ hybridisation was employed to examine circHIPK3 expression in cardiac fibroblasts. RNA immunoprecipitation and luciferase reporter assay were conducted to explore the pathological mechanism of circHIPK3 in myocardial fibrosis. RESULTS: Knockdown of circHIPK3 was found to attenuate myocardial fibrosis and enhance cardiac function in DCM mice. In addition, silencing of circHIPK3 could suppress proliferation of cardiac fibroblasts treated with angiotensin II. Furthermore, RNA immunoprecipitation and luciferase reporter assay revealed a circHIPK3-miR-29b-3p-Col1a1-Col3a1 regulatory network in the pathogenesis of myocardial fibrosis. CONCLUSIONS/INTERPRETATION: circHIPK3 contributes to increased myocardial fibrosis during DCM by functioning as a competing endogenous RNA that upregulates Col1a1 and Col3a1 expression through suppressing miR-29b-3p.


Asunto(s)
Proliferación Celular , Cardiomiopatías Diabéticas/metabolismo , Fibroblastos/metabolismo , Miocardio/metabolismo , ARN Circular/metabolismo , Angiotensina II/farmacología , Animales , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Cadena alfa 1 del Colágeno Tipo I/genética , Cadena alfa 1 del Colágeno Tipo I/metabolismo , Colágeno Tipo III/genética , Colágeno Tipo III/metabolismo , Cardiomiopatías Diabéticas/genética , Cardiomiopatías Diabéticas/patología , Modelos Animales de Enfermedad , Fibroblastos/efectos de los fármacos , Fibroblastos/patología , Fibrosis , Regulación de la Expresión Génica , Masculino , Ratones Endogámicos C57BL , MicroARNs/genética , MicroARNs/metabolismo , Miocardio/patología , ARN Circular/genética , Transducción de Señal
15.
J Am Chem Soc ; 143(1): 60-64, 2021 01 13.
Artículo en Inglés | MEDLINE | ID: mdl-33356211

RESUMEN

Single-site catalysts have drawn broad attention in catalysis because of their maximum atomic utilization and unique catalytic performance. Early work in our group has shown a 40-fold higher activity of methanol decomposition over single-site Pt1/CeO2 catalyst than CeO2 supported 2.5 nm Pt nanoparticles, while a molecular-level understanding of such enhancement is lacking. Herein, the reaction mechanism of methanol decomposition over Pt1/CeO2 was carefully investigated using in situ DRIFTS, and a reaction pathway was proposed. Methanol molecules were dissociatively adsorbed on nanoceria support first, followed by the diffusion of as-formed methoxy species onto Pt single sites where the dehydrogenation occurs and results in the weakly bonded CO. The ease of methanol dissociative adsorption on nanoceria support and the tailored electronic property of Pt1 via the metal-support interaction are believed to be strongly correlated with the high activity of Pt1/CeO2.

16.
Small ; 17(47): e2103433, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34558176

RESUMEN

Great efforts have been devoted to searching for efficient catalytic systems to produce ultra-high density single-walled carbon nanotube (SWNT) arrays, which lay the foundation for future electronic devices. However, one major obstacle for realizing high-density surface-aligned SWNT arrays is the poor stability of metal nanoparticles in chemical vapor deposition catalytic processes. Recently, Trojan catalyst has been reported to yield unprecedented high-density SWNT arrays with 130 SWNTs per µm on the a-plane (11-20) of the sapphire substrate. Herein, a concept of catalyst confinement effect is put forward to revealing the secret of remarkable growth efficiency of SWNT arrays by Trojan catalyst. Combined experimental and theoretical studies indicate that confinement of catalyst nanoparticles on discrete a-plane strips plays a key role in stabilizing the small nanoparticles. The highly dispersive and active states of catalysts are maintained, which promote the growth of super-dense SWNT arrays. By rationally designing the substrate reconstruction process, large areas of dense SWNT arrays (130 SWNTs per µm) covering the entire substrate are obtained. This approach may provide novel ideas for the synthesis of various high-density 1D nanomaterials.


Asunto(s)
Nanopartículas , Nanotubos de Carbono , Catálisis
17.
Clin Exp Allergy ; 51(12): 1566-1576, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34075657

RESUMEN

BACKGROUND: Airway eosinophilic inflammation is a central feature in asthma which is mainly driven by type 2 response. The expression of galectin-13 was up-regulated in a parasitic infection model which is also characterized by type 2 immune response. We hypothesized that galectin-13 may be involved in airway eosinophilic inflammation in asthma. OBJECTIVE: To unveil the role of galectin-13 in asthma airway inflammation. METHODS: We measured galectin-13 expressions in bronchial brushings, sputum, and plasma of asthma patients (n = 54) and healthy controls (n = 15), and analysed the correlations between galectin-13 expression and airway eosinophilia. We used human bronchial epithelial cell line 16HBE to investigate the possible mechanism by which galectin-13 participates in eosinophilic inflammation. RESULTS: The expression of galectin-13 was markedly increased in subjects with asthma compared to controls. Epithelial galectin-13 mRNA levels in asthmatic subjects were strongly correlated with eosinophilic airway inflammation (the percentage of sputum eosinophils, the number of eosinophils in bronchial submucosa and FeNO) and the expression of Th2 signature genes (CLCA1, POSTN and SERPINB2). Inhaled corticosteroid (ICS) treatment reduced plasma galectin-13 levels, and baseline plasma galectin-13 levels reflect the response to ICS treatment. In cultured 16HBE cells, knockdown of galectin-13 suppressed IL-13-stimulated MCP-1 and eotaxin-1 expression by inhibiting the activation of EGFR and ERK. CONCLUSIONS & CLINICAL RELEVANCE: Galectin-13 is a novel marker for airway eosinophilia in asthma, and may contribute to allergic airway eosinophilic inflammation by up-regulating the expression of MCP-1 and eotaxin-1. Plasma galectin-13 levels may be useful for predicting responses to ICS treatment.


Asunto(s)
Asma , Eosinofilia , Galectinas/metabolismo , Proteínas Gestacionales/metabolismo , Asma/tratamiento farmacológico , Eosinofilia/genética , Eosinófilos/metabolismo , Humanos , Inflamación/metabolismo , Esputo/metabolismo
18.
Int Arch Allergy Immunol ; 182(12): 1200-1211, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34320489

RESUMEN

INTRODUCTION: Asymptomatic sensitization is defined as the presence of positive skin prick test (SPT) and/or positive serum allergen-specific IgE in the absence of clinical allergic symptoms. Currently, there is no convincing explanation why some people with positive allergen tests do not show symptoms. We aimed to investigate the house dust mite (HDM)-specific IgE and IgG4 repertoire in asymptomatic HDM-sensitized subjects and HDM-induced allergic rhinitis (AR) patients. METHODS: A total of 48 subjects sensitized to HDM were included in this study: 27 had AR with/without asthma (symptomatic group), and 21 had no allergic symptoms (asymptomatic group). Six healthy individuals served as control group. Peripheral blood samples were collected for serum IgE and IgG4 assay and basophil activation tests (BATs). IgE and IgG4 assay included antibodies to Dermatophagoides (Der) p1, 2, 7, 10, 21, 23, and Der f1, 2. RESULTS: AR patients had a larger wheal diameter of SPT (7.0 vs. 3.0 mm, p < 0.0001) and a higher specific IgE to Der p (15.50 vs. 0.70 KU/L, p < 0.0001) than asymptomatic subjects. They also showed more frequent sensitization to Der p1 and Der p2 (both p < 0.05). However, the total IgE and specific IgG4 did not differ significantly between the 2 groups. The basophil activation response after being stimulated with HDM was observed to be higher in AR patients (all p < 0.05). CONCLUSIONS: There are differences in SPT, serum-specific IgE to Der p, component allergen Der p1 and Der p2 level and BAT between AR patients and asymptomatic subjects sensitized to HDM. IgG4 alone cannot differentiate asymptomatic individuals from AR patients.


Asunto(s)
Alérgenos/inmunología , Antígenos Dermatofagoides/inmunología , Enfermedades Asintomáticas , Inmunoglobulina E/sangre , Inmunoglobulina G/sangre , Rinitis Alérgica Perenne/inmunología , Adulto , Biomarcadores/sangre , Estudios de Casos y Controles , Femenino , Humanos , Masculino , Persona de Mediana Edad , Curva ROC , Rinitis Alérgica Perenne/sangre , Rinitis Alérgica Perenne/diagnóstico , Pruebas Cutáneas , Adulto Joven
19.
Mol Ther ; 28(10): 2111-2119, 2020 10 07.
Artículo en Inglés | MEDLINE | ID: mdl-32910911

RESUMEN

Cardiovascular diseases (CVDs) remain the leading cause of death and disability worldwide, despite marked improvements in prevention, diagnosis, and early intervention. There is an urgent need to discover more effective therapeutic strategies, which would be facilitated by a more in-depth understanding of CVDs and their underlying molecular mechanisms. Recent advances in knowledge about epigenetic mechanisms, especially RNA methylation, have revealed a close relationship between epigenetic modifications and CVDs and have brought to potential novel targets for diagnosis and treatment. Here, we provide a review of recent studies exploring RNA N6-methyladenosine (m6A) modification, with particular emphasis on its role in CVDs, such as coronary heart disease, hypertension, cardiac hypertrophy, and heart failure. We also introduce the "life cycle" of m6A and its dominant function in several biological processes. Finally, we highlight the prospects of treatment based on interfering with m6A, which could have a transformative effect on clinical medicine.


Asunto(s)
Adenosina/análogos & derivados , Enfermedades Cardiovasculares/etiología , ARN/metabolismo , Adenosina/metabolismo , Enfermedades Cardiovasculares/diagnóstico , Enfermedades Cardiovasculares/tratamiento farmacológico , Enfermedades Cardiovasculares/metabolismo , Susceptibilidad a Enfermedades , Epigénesis Genética , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Metilación , Terapia Molecular Dirigida , ARN/genética
20.
J Am Chem Soc ; 142(39): 16533-16537, 2020 09 30.
Artículo en Inglés | MEDLINE | ID: mdl-32926771

RESUMEN

We demonstrate that the single-site catalyst Pt1/CeO2 greatly enhances the selectivity of cyclization and aromatization in the n-hexane reforming reaction. Specifically, the selectivity of single-site Pt1/CeO2 toward both cyclization and aromatization is above 86% at 350 °C. The turnover frequency of Pt1/CeO2 is 58.8 h-1 at 400 °C, which is close to that of Pt cluster/CeO2 (61.4 h-1) and much higher than that of Pt nanoparticle/CeO2 with Pt sizes of 2.5 and 7 nm. On the basis of the catalytic results for methylcyclopentane reforming, the dehydrocyclization and further aromatization of n-hexane are attributed to the prominent adsorption of ring intermediate products on the single-site Pt1/CeO2 catalysts. On the other side, with the multiple Pt adjacent active sites, the cluster and nanoparticle Pt/CeO2 samples favor the C-C bond cracking reaction. Ultimately, this in-depth study unravels the principles of hydrocarbon activation with different Pt sizes and represents a key step toward the rational design of new heterogeneous catalysts.

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