Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Proc Natl Acad Sci U S A ; 120(45): e2308035120, 2023 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-37883417

RESUMO

Metallic nickel (Ni) is a promising candidate to substitute Pt-based catalysts for hydrogen oxidation reaction (HOR), but huge challenges still exist in precise modulation of the electronic structure to boost the electrocatalytic performances. Herein, we present the use of single-layer Ti3C2Tx MXene to deliberately tailor the electronic structure of Ni nanoparticles via interfacial oxygen bridges, which affords Ni/Ti3C2Tx electrocatalyst with exceptional performances for HOR in an alkaline medium. Remarkably, it shows a high kinetic current of 16.39 mA cmdisk-2 at the overpotential of 50 mV for HOR [78 and 2.7 times higher than that of metallic Ni and Pt/C (20%), respectively], also with good durability and CO antipoisoning ability (1,000 ppm) that are not available for conventional Pt/C (20%) catalyst. The ultrahigh conductivity of single-layer Ti3C2Tx provides fast transmission of electrons for Ni nanoparticles, of which the uniform and small sizes endow them with high-density active sites. Further, the terminated -O/-OH functional groups on Ti3C2Tx directionally capture electrons from Ni nanoparticles via interfacial Ni-O bridges, leading to obvious electronic polarization. This could enhance the Nids-O2p interaction and weaken Nids-H1s interaction of Ni sites in Ni/Ti3C2Txenabling a suitable H-/OH-binding energy and thus enhancing the HOR activity.

2.
Angew Chem Int Ed Engl ; : e202418017, 2024 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-39444057

RESUMO

Precise adjusting the band gaps in metal-organic frameworks (MOFs) is crucial for improving their visible-light absorption capacity during photocatalysis, presenting both a formidable challenge and a charming opportunity. This present study employed a symmetry-reduction strategy to pre-design six novel 4-connected ligands with systematic substituents (-NO2, -H, -tBu, -OCH3, -OH and -NH2) and synthesized the corresponding pillared-layer Zr-MOFs (NKM-668) retaining the hexaphenylbenzene fragment. Subsequently, the NKM-668 MOFs were transformed into large-π-conjugated hexabenzocoronene-based MOFs (pNKM-668) via the Scholl reaction. These twelve MOFs exhibited broad and tunable band gaps over 1.41 eV (ranging from 3.25 eV to 1.84 eV), and the photocatalytic CO2 conversion rate raised by 33.2-fold. This study not only enriches the type of hexaphenylbenzene-based MOFs, but also paves the way for nanographene-containing MOFs in the further application of photocatalysis.

3.
J Psycholinguist Res ; 52(5): 1371-1395, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37022626

RESUMO

This longitudinal study made the first attempt to employ Latent Growth Curve Modeling to analyze the development of L2 speaking accuracy and fluency through online scaffolding as well as the dynamic relationship between L2 speaking performance and self-efficacy. From the perspective of Complex Dynamic Systems Theory, it tracked the development of 45 Chinese undergraduates' English-speaking accuracy, fluency, self-efficacy for accuracy (SEA) and self-efficacy for fluency (SEF) over one semester of online teaching (six observations). Results show that speaking accuracy, SEA and SEF all improved significantly, but speaking fluency did not; these four variables all developed in non-linear trajectories, and the greatest growth of accuracy, SEA and SEF all took place at Time 2; there existed significant individual differences in the initial levels of fluency, SEA and SEF, and in the change rates of SEA; a higher initial level of accuracy was related to a greater increase in SEA and a greater decrease in growth rates with time. These findings provide evidence for non-linearity, variability and inter-individual differences in the development of L2 speaking and self-efficacy through online scaffolding, and partly confirm the dynamic relations between self-efficacy and L2 performance. Pedagogical implications for online scaffolding are also discussed.


Assuntos
Idioma , Autoeficácia , Humanos , Estudos Longitudinais
4.
World J Clin Cases ; 12(17): 3027-3034, 2024 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-38898832

RESUMO

BACKGROUND: Current treatments for chronic heart failure (CHF) are therapeutically ineffective. The optimization of treatments for this disease needs to be explored and analyzed. AIM: To analyze the effect of using Luhong Formula in the cardiac rehabilitation of patients with CHF and its influence on cardiopulmonary function (CPF) and prognosis. METHODS: In total, 160 patients with CHF admitted between June 2022 and June 2023 were selected, including 75 receiving perindopril (control group) and 85 receiving Luhong Formula (research group). We conducted comparative analyses on the curative effects of traditional Chinese medicine (TCM) syndromes and cardiac function, CPF [oxygen consumption at the anaerobic threshold (VO2 AT) and at peak exercise (peak VO2)], echocardiographic indexes [left atrial volume index (LAVI), left ventricular muscle mass index (LVMI), left ventricular ejection fraction (LVEF)], and prognosis [major adverse cardiovascular events (MACEs) at 6 months follow-up]. RESULTS: The research group showed markedly higher curative effects of TCM syndromes and cardiac function than the control group. In addition, post-treatment VO2 AT, peak VO2, LVMI and LVEF in the research group were significantly higher, whereas LAVI was significantly lower, than those of the control group. Furthermore, fewer patients in the research group developed MACEs at the 6-month follow-up. CONCLUSION: Luhong Formula is more therapeutically effective than perindopril for the cardiac rehabilitation of patients with CHF, specifically in enhancing CPF and prognosis.

5.
Chempluschem ; 89(9): e202400158, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38733075

RESUMO

Photocatalytic technology can efficiently convert solar energy to chemical energy and this process is considered as one of the green and sustainable technology for practical implementation. In recent years, metal-organic frameworks (MOFs) have attracted widespread attention due to their unique advantages and have been widely applied in the field of photocatalysis. Among them, noble metals have contributed significant advances to the field as effective catalysts in photocatalytic reactions. Importantly, noble metals can also form a synergistic catalytic effect with MOFs to further improve the efficiency of photocatalytic reactions. However, how to precisely control the synergistic effect between MOFs and noble metals to improve the photocatalytic performance of materials still needs to be further studied. In this review, the synergistic effects of MOFs and noble metal catalysts in photocatalytic reactions are firstly summarized in terms of noble metal nanoparticles, noble metal monoatoms, noble metal compounds, and noble metal complexes, and focus on the mechanisms and advantages of these synergistic effects, so as to provide useful guidance for the further research and application of MOFs and contribute to the development of the field of photocatalysis.

6.
Brain Behav ; 13(8): e3131, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37337730

RESUMO

BACKGROUND: Williams syndrome is an autosomal dominant multisystem disorder caused by a 1.5-1.8 Mb deletion on chromosome 7q11.23. It is characterized by facial deformations, cardiovascular abnormalities, developmental delays, gastrointestinal manifestations, and endocrine disorders. CASE DESCRIPTION: A 1-year-old child presenting with developmental delays, special facial features, gastrointestinal bleeding, renal calcium deposition, and hypotonia was admitted to the hospital for "hypercalcemia and gastrointestinal bleeding." Genetic testing showed a deletion mutation in the 7q11.23 region. Currently, the child receiving treatment to promote calcium excretion and rehabilitation training, but hypercalcemia has recurred. CONCLUSION: The clinical phenotype of Williams syndrome is complex, and different severities, characterized by developmental delays, facial deformities, cardiovascular abnormalities, gastrointestinal symptoms and endocrine disorders, should be considered in children. The syndrome may require thorough genetic testing for diagnosis and early intervention treatment to improve patient quality of life.


Assuntos
Hipercalcemia , Síndrome de Williams , Humanos , Síndrome de Williams/complicações , Síndrome de Williams/diagnóstico , Síndrome de Williams/genética , Hipercalcemia/complicações , Hipercalcemia/diagnóstico , Cálcio , Qualidade de Vida , Hemorragia Gastrointestinal/etiologia
7.
Nat Commun ; 13(1): 3857, 2022 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-35790749

RESUMO

The active-site density, intrinsic activity, and durability of Ni-based catalysts are critical to their application in industrial alkaline water electrolysis. This work develops a kind of promoters, the bixbyite-type lanthanide metal sesquioxides (Ln2O3), which can be implanted into metallic Ni by selective high-temperature reduction to achieve highly efficient Ni/Ln2O3 hybrid electrocatalysts toward hydrogen evolution reaction. The screened Ni/Yb2O3 catalyst shows the low overpotential (20.0 mV at 10 mA cm-2), low Tafel slope (44.6 mV dec-1), and excellent long-term durability (360 h at 500 mA cm-2), significantly outperforming the metallic Ni and benchmark Pt/C catalysts. The remarkable hydrogen evolution activity and stability of Ni/Yb2O3 are attributed to that the Yb2O3 promoter with high oxophilicity and thermodynamic stability can greatly enlarge the active-site density, reduce the energy barrier of water dissociation, optimize the free energy of hydrogen adsorption, and avoid the oxidation corrosion of Ni.

8.
Nat Commun ; 11(1): 4211, 2020 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-32839440

RESUMO

Surface plasmons (SPs) of metals enable the tight focusing and strong absorption of light to realize an efficient utilization of photons at nanoscale. In particular, the SP-generated hot carriers have emerged as a promising way to efficiently drive photochemical and photoelectric processes under moderate conditions. In situ measuring of the transport process and spatial distribution of hot carriers in real space is crucial to efficiently capture the hot carriers. Here, we use electrochemical tip-enhanced Raman spectroscopy (EC-TERS) to in situ monitor an SP-driven decarboxylation and resolve the spatial distribution of hot carriers with a nanometer spatial resolution. The transport distance of about 20 nm for the reactive hot carriers is obtained from the TERS imaging result. The hot carriers with a higher energy have a shorter transport distance. These conclusions can be guides for the design and arrangement of reactants and devices to efficiently make use of plasmonic hot carriers.

9.
Front Pharmacol ; 10: 1095, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31616303

RESUMO

Shengmai injection (SMI), a traditional Chinese herbal medicine extracted from Panax ginseng C.A. Mey., Ophiopogon japonicus (Thunb.) Ker Gawl., and Schisandra chinensis (Turcz.) Baill., has been used to treat acute and chronic heart failure. This study aimed to further clarify the effects of SMI on energy metabolism. SMI could improve cell-survival rate and also reduce myocardial cell hypertrophy and apoptosis. Mitochondria are important sites of cellular energy metabolism, and SMI protects mitochondrial function which was evaluated by mitochondrial ultrastructure, mitochondrial respiratory control ratio (RCR), and mitochondrial membrane potential (ΔΨm) in this study. The expression levels of adenosine triphosphate (ATP), adenosine diphosphate (ADP), and phosphocreatine (PCr) increased. The expression levels of free fatty acid oxidation [carnitine palmitoyltransferase-1 (CPT-1)], glucose oxidation [glucose transporter-4 (GLUT-4)], and mitochondrial biogenesis-related genes (peroxisome proliferator-activated receptor-γ coactivator-1α [PGC-1α]) were upregulated after SMI treatment. AMP-activated protein kinase (AMPK) is an important signaling pathway regulating energy metabolism and also can regulate the above-mentioned indicators. In the present study, SMI was found to promote phosphorylation of AMPK. However, the effects of SMI on fatty acid, glucose oxidation, mitochondrial biogenesis, as well as inhibiting apoptosis of hypertrophic cardiomyocytes were partly blocked by AMPK inhibitor-compound C. Moreover, decreased myocardial hypertrophy and apoptosis treated by SMI were inhibited by AMPK knockdown with shAMPK to a certain degree and AMPK knockdown almost abolished the SMI-induced increase in the expression of GLUT-4, CPT-1, and PGC-1α. These data suggest that SMI suppressed Ang II-induced cardiomyocyte hypertrophy and apoptosis via activation of the AMPK signaling pathway through energy-dependent mechanisms.

10.
Nanoscale ; 10(9): 4398-4405, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29451566

RESUMO

Tip-enhanced Raman spectroscopy (TERS), known as nanospectroscopy, has received increasing interest as it can provide nanometer spatial resolution and chemical fingerprint information of samples simultaneously. Since Ag tips are well accepted to show a higher TERS enhancement than that of gold tips, there is an urgent quest for Ag TERS tips with a high enhancement, long lifetime, and high reproducibility, especially for atomic force microscopy (AFM)-based TERS. Herein, we developed an electrodeposition method to fabricate Ag-coated AFM TERS tips in a highly controllable and reproducible way. We investigated the influence of the electrodeposition potential and time on the morphology and radius of the tip. The radii of Ag-coated AFM tips can be rationally controlled at a few to hundreds nanometers, which allows us to systematically study the dependence of the TERS enhancement on the tip radius. The Ag-coated AFM tips show the highest TERS enhancement under 632.8 nm laser excitation and a broad localized surface plasmon resonance (LSPR) response when coupled to a Au substrate. The tips exhibit a lifetime of 13 days, which is particularly important for applications that need a long measuring time.

11.
Exp Ther Med ; 5(5): 1363-1366, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23737880

RESUMO

The aim of this study was to explore the chronergy of intravenous recombinant streptokinase (r-SK) in patients with acute myocardial infarction (AMI). A total of 114 patients were divided into two groups according to the time of AMI onset: the morning onset (6:01-12:00, n=53) and non-morning onset (12:01-06:00, n=61) groups. The recanalization rate was recorded, as well as anticoagulant and fibrinolytic indices. Statistical analysis was performed to evaluate the recanalization rate following thrombolysis, as well as the anticoagulant and fibrinolytic activities. The recanalization rates following thrombolysis in the morning onset and non-morning onset groups were 60.4 and 82.0%, respectively (P<0.05). The level of plasminogen activator inhibitor-1 (PAI-1) antigen was significantly higher in the morning onset group compared with that in the non-morning onset group (P<0.05). This indicated a resistance to r-SK thrombolysis in the morning at the early stage of AMI, which possibly correlates with increased PAI-1 antigen levels and activity.

12.
Inorg Chem ; 44(2): 382-92, 2005 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-15651885

RESUMO

For this study, the N'-monoamide derivatives of TTDA (3,6,10-tri(carboxymethyl)-3,6,10-triazadodecanedioic acid), N'-methylamide (TTDA-MA), N'-benzylamide (TTDA-BA), and N'-2-methoxybenzylamide (TTDA-MOBA), were synthesized. Their protonation constants and stability constants (log K(ML)'s) formed with Ca(2+), Zn(2+), Cu(2+), and Gd(3+) were determined by potentiometric titration in 0.10 M Me(4)NCl at 25.0 +/- 0.1 degrees C. The relaxivity values of [Gd(TTDA-MA)](-), [Gd(TTDA-BA)](-), and [Gd(TTDA-MOBA)](-) remained constant with respect to pH changes over the range 4.5-12.0. The (17)O NMR chemical shift of H(2)O induced by [Dy(TTDA-MA)(H(2)O)](-) at pH 6.80 showed 0.9 inner-sphere water molecules. Water proton relaxivity values for [Gd(TTDA-MA)(H(2)O)](-), [Gd(TTDA-BA)(H(2)O)](-), and [Gd(TTDA-MOBA)(H(2)O)](-) at 37.0 +/- 0.1 degrees C and 20 MHz are 3.89, 4.21, and 4.25, respectively. The water-exchange lifetime (tau(M)) and rotational correlation time (tau(R)) of [Gd(TTDA-MA)(H(2)O)](-), [Gd(TTDA-BA)(H(2)O)](-), and [Gd(TTDA-MOBA)(H(2)O)](-) are obtained from reduced the (17)O relaxation rate and chemical shifts of H(2)(17)O. The (2)H NMR longitudinal relaxation rates of the deuterated diamagnetic lanthanum complexes for the rotational correlation time were also thoroughly investigated. The water-exchange rates (K(298)(ex) for [Gd(TTDA-MA)(H(2)O)](-), [Gd(TTDA-BA)(H(2)O)](-), and [Gd(TTDA-MOBA)(H(2)O)](-) are lower than that of [Gd(TTDA)(H(2)O)](2)(-) but significantly higher than those of [Gd(DTPA)(H(2)O)](2)(-) and [Gd(DTPA-BMA)(H(2)O)]. The rotational correlation times for [Gd(TTDA-BA)(H(2)O)](-) and [Gd(TTDA-MOBA)(H(2)O)](-) are significantly longer than those of [Gd(TTDA)(H(2)O)](2)(-) and [Gd(DTPA)(H(2)O)](2)(-) complexes. The marked increase of the relaxivity of [Gd(TTDA-BA)(H(2)O)](-) and [Gd(TTDA-MOBA)(H(2)O)](-) results mainly from their longer rotational correlation time. The noncovalent interaction between human serum albumin (HSA) and [Gd(TTDA-BA)(H(2)O)](-) and [Gd(TTDA-MOBA)(H(2)O)](-) complexes containing a hydrophobic substituent was investigated by measuring the water proton relaxation rate of the aqueous solutions. The binding association constant (K(A)) values are 1.0 +/- 0.2 x 10(3) and 1.3 +/- 0.2 x 10(3) M(-1) for [Gd(TTDA-BA)(H(2)O)](-) and [Gd(TTDA-MOBA)(H(2)O)](-), which indicates a stronger interaction of [Gd(TTDA-BA)(H(2)O)](-) and [Gd(TTDA-MOBA)(H(2)O)](-) with HSA.


Assuntos
Amidinas/química , Amidinas/síntese química , Gadolínio/química , Compostos Organometálicos/química , Compostos Organometálicos/síntese química , Catálise , Indicadores e Reagentes , Ligantes , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Termodinâmica
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA