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1.
J Am Chem Soc ; 146(3): 2167-2173, 2024 Jan 24.
Artículo en Inglés | MEDLINE | ID: mdl-38214166

RESUMEN

Due to the large multi-elemental space desired for property screening and optimization, high-entropy alloys (HEAs) hold greater potential over conventional alloys for a range of applications, such as structural materials, energy conversion, and catalysis. However, the relationship between the HEA composition and its local structural/elemental configuration is not well understood, particularly in noble-metal-based HEA nanomaterials, hindering the design and development of nano-HEAs in energy conversion and catalysis applications. Herein, we determined precise atomic-level structural and elemental arrangements in model HEAs composed of RhPtPdFeCo and RuPtPdFeCo to unveil their local characteristics. Notably, by changing just one constituent element in the HEA (Rh to Ru), we found dramatic changes in the elemental arrangement from complete random mixing to a local single elemental ordering feature. Additionally, we demonstrate that the local ordering in RuPtPdFeCo can be further controlled by varying the Ru concentration, allowing us to toggle between local Ru clustering and distinct heterostructures in multicomponent systems. Overall, our study presents a practical approach for manipulating local atomic structures and elemental arrangements in noble-metal-based HEA systems, which could provide in-depth knowledge to mechanistically understand the functionality of noble-metal-based HEA nanomaterials in practical applications.

2.
J Am Chem Soc ; 146(15): 10908-10916, 2024 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-38579155

RESUMEN

Self-assembly of sophisticated polyhedral cages has drawn much attention because of their elaborate structures and potential applications. Herein, we report the anion-coordination-driven assembly of the first A8L12 (A = anion, L = ligand) octanuclear cubic structures from phosphate anion and p-xylylene-spaced bis-bis(urea) ligands via peripheral templating of countercations (TEA+ or TPA+). By attaching terminal aryl rings (phenyl or naphthyl) to the ligand through a flexible (methylene) linker, these aryls actively participate in the formation of plenty of "aromatic pockets" for guest cation binding. As a result, multiple peripheral guests (up to 22) of suitable size are bound on the faces and vertices of the cube, forming a network of cation-π interactions to stabilize the cube structure. More interestingly, when chiral ligands were used, either diastereomers of mixed Λ- and Δ-configurations (with TEA+ countercation) for the phosphate coordination centers or enantiopure cubes (with TPA+) were formed. Thus, the assembly and chirality of the cube can be modulated by remote terminal groups and peripheral templating tetraalkylammonium cations.

3.
J Am Chem Soc ; 146(2): 1423-1434, 2024 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-38171910

RESUMEN

Cu-based catalysts hold promise for electrifying CO2 to produce methane, an extensively used fuel. However, the activity and selectivity remain insufficient due to the lack of catalyst design principles to steer complex CO2 reduction pathways. Herein, we develop a concept to design carbon-supported Cu catalysts by regulating Cu active sites' atomic-scale structures and engineering the carbon support's mesoscale architecture. This aims to provide a favorable local reaction microenvironment for a selective CO2 reduction pathway to methane. In situ X-ray absorption and Raman spectroscopy analyses reveal the dynamic reconstruction of nitrogen and hydroxyl-immobilized Cu3 (N,OH-Cu3) clusters derived from atomically dispersed Cu-N3 sites under realistic CO2 reduction conditions. The N,OH-Cu3 sites possess moderate *CO adsorption affinity and a low barrier for *CO hydrogenation, enabling intrinsically selective CO2-to-CH4 reduction compared to the C-C coupling with a high energy barrier. Importantly, a block copolymer-derived carbon fiber support with interconnected mesopores is constructed. The unique long-range mesochannels offer an H2O-deficient microenvironment and prolong the transport path for the CO intermediate, which could suppress the hydrogen evolution reaction and favor deep CO2 reduction toward methane formation. Thus, the newly developed catalyst consisting of in situ constructed N,OH-Cu3 active sites embedded into bicontinuous carbon mesochannels achieved an unprecedented Faradaic efficiency of 74.2% for the CO2 reduction to methane at an industry-level current density of 300 mA cm-2. This work explores effective concepts for steering desirable reaction pathways in complex interfacial catalytic systems via modulating active site structures at the atomic level and engineering pore architectures of supports on the mesoscale to create favorable microenvironments.

4.
Biochem Biophys Res Commun ; 704: 149706, 2024 04 16.
Artículo en Inglés | MEDLINE | ID: mdl-38432144

RESUMEN

Glioma patients often undertake psychiatric disorders such as depression and anxiety. There are several clinical epidemiological studies on glioma-associated depression, but basic research and corresponding animal experiments are still lacking. Here, we observed that glioma-bearing mice exhibited atypical depression-like behaviors in orthotopic glioma mouse models. The concentrations of monoamine neurotransmitters were detected by enzyme-linked immunosorbent assay (ELISA), revealing a decrease in 5-hydroxytryptamine (5-HT) levels in para-glioma tissues. The related gene expression levels also altered, detected by quantitative RT-PCR. Then, we developed a glioma-depression comorbidity mouse model. Through sucrose preference test (SPT), forced swimming test (FST), tail suspension test (TST) and other tests, we found that the occurrence of glioma could lead to changes in depression-like behaviors in a chronic unpredictable mild stress (CUMS) mouse model. The results of RNA sequencing (RNA-seq) indicated that the altered expression of glutamatergic synapse related genes in the paratumor tissues might be one of the main molecular features of the comorbidity model. Our findings suggested that the presence of glioma caused and altered depression-like behaviors, which was potentially related to the 5-HT and glutamatergic synapse pathways.


Asunto(s)
Depresión , Serotonina , Humanos , Ratones , Animales , Depresión/metabolismo , Serotonina/metabolismo , Antidepresivos/farmacología , Conducta Animal , Natación , Estrés Psicológico/metabolismo , Modelos Animales de Enfermedad , Hipocampo/metabolismo
5.
Nat Mater ; 22(1): 100-108, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36266572

RESUMEN

Iridium-based electrocatalysts remain the only practical anode catalysts for proton exchange membrane (PEM) water electrolysis, due to their excellent stability under acidic oxygen evolution reaction (OER), but are greatly limited by their high cost and low reserves. Here, we report a nickel-stabilized, ruthenium dioxide (Ni-RuO2) catalyst, a promising alternative to iridium, with high activity and durability in acidic OER for PEM water electrolysis. While pristine RuO2 showed poor acidic OER stability and degraded within a short period of continuous operation, the incorporation of Ni greatly stabilized the RuO2 lattice and extended its durability by more than one order of magnitude. When applied to the anode of a PEM water electrolyser, our Ni-RuO2 catalyst demonstrated >1,000 h stability under a water-splitting current of 200 mA cm-2, suggesting potential for practical applications. Density functional theory studies, coupled with operando differential electrochemical mass spectroscopy analysis, confirmed the adsorbate-evolving mechanism on Ni-RuO2, as well as the critical role of Ni dopants in stabilization of surface Ru and subsurface oxygen for improved OER durability.

6.
Respir Res ; 25(1): 147, 2024 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-38555425

RESUMEN

Inflammation and immune processes underlie pulmonary hypertension progression. Two main different activated phenotypes of macrophages, classically activated M1 macrophages and alternatively activated M2 macrophages, are both involved in inflammatory processes related to pulmonary hypertension. Recent advances suggest that macrophages coordinate interactions among different proinflammatory and anti-inflammatory mediators, and other cellular components such as smooth muscle cells and fibroblasts. In this review, we summarize the current literature on the role of macrophages in the pathogenesis of pulmonary hypertension, including the origin of pulmonary macrophages and their response to triggers of pulmonary hypertension. We then discuss the interactions among macrophages, cytokines, and vascular adventitial fibroblasts in pulmonary hypertension, as well as the potential therapeutic benefits of macrophages in this disease. Identifying the critical role of macrophages in pulmonary hypertension will contribute to a comprehensive understanding of this pathophysiological abnormality, and may provide new perspectives for pulmonary hypertension management.


Asunto(s)
Hipertensión Pulmonar , Humanos , Hipertensión Pulmonar/etiología , Macrófagos , Macrófagos Alveolares/patología , Inflamación/complicaciones , Citocinas
7.
Am J Nephrol ; : 1-22, 2024 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-39321787

RESUMEN

INTRODUCTION: Mycophenolate mofetil (MMF) is widely used off-label in patients with immunoglobulin A nephropathy (IgAN), although the literature does not consistently agree on its efficacy and safety. METHODS: We systematically searched PubMed, Embase, CENTRAL, CNKI, VIP, Wanfang Data, and SinoMed from their inception to August 2023. We included randomized controlled trials that enrolled patients of IgAN who received MMF treatment and compared effects with placebo or as an add-on therapy to usual care. Literature screening, risk of bias assessment, and data extraction were independently conducted in duplicate. Fixed-effects or random-effects meta-analyses were performed for pooling data where eligible. The primary outcomes were the composite kidney outcomes of major adverse kidney events (MAKDE) defined as doubling of serum creatinine, end-stage renal disease (ESRD), or death from a kidney disease-related or cardiovascular cause. RESULTS: Of 13 studies identified, 918 participants (463 [50.4%] treated with MMF) with IgAN were included in the analysis. MMF treatment in IgAN was associated with decreasing the occurrence of MAKDE (RR, 0.32; 95%CI, 0.13 to 0.77), reducing proteinuria (RR, 1.41; 95%CI, 1.22 to 1.64), and lessening the probability of doubling blood creatinine (RR, 0.32, 95% CI, 0.14 to 0.72). No significant differences were detected in the incidence of ESRD (RR: 0.87, 95% CI: 0.38 to 2.03), or progression of chronic kidney disease (RR, 1.01; 95%CI, 0.22 to 4.57). Patients receiving MMF had a higher risk of infection (RR, 2.20; 95%CI, 1.21 to 4.00). CONCLUSION: MMF administration in IgAN indicates promising in decreasing the occurrence of MAKDE, reducing proteinuria level, and lessening the probability of doubling blood creatinine, but also comes with the risk of infection. These findings tend to be introduced to non-Caucasian population. The long-term favorable effects that MMF improved kidney outcomes still needs need further cross-regional and cross-ethnical verification.

8.
Phys Chem Chem Phys ; 2024 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-39355876

RESUMEN

Liquid metal batteries have received considerable attention owing to their excellent properties. However, an electrolyte with low melting temperature is required to decrease operating temperature for the safety of liquid metal batteries and for saving energy. For revealing the mechanism of low liquefaction temperature, an empirical electron theory of solid molecules was used to study the thermal properties of pure lithium halides and their ternary-phase systems systematically. The theoretical bond lengths, melting points, liquefaction temperatures and mixed energies of pure lithium halides and their ternary phases match the experimental values well. The mechanism of liquefaction temperature for ternary lithium halides depends on their valence electron structures. The liquefaction temperature can be stabilized on a liquidus line or curve through the modulation of the constant number of covalent electrons (nc) and lattice electrons (nl). The liquefaction temperatures on various liquidus lines and curves are positively related to the linear density of valence electron pairs on the strong Li-X bond, bonding factor, and number of valence electrons in the s orbital but are negatively related to the number of valence electrons in the p orbital. With an increase in the linear density of the valence electron pair number and bonding factor, bond strength is enhanced, which increases the resistance of the strong Li-X bond against the break force induced by thermal phonon vibrations, and more thermal phonons with high vibrating energy are required for breaking the strongest Li-X bond at a higher temperature; therefore, the liquefaction temperature increases.

9.
Environ Res ; 263(Pt 1): 120050, 2024 Sep 23.
Artículo en Inglés | MEDLINE | ID: mdl-39322057

RESUMEN

The Yangtze Finless Porpoise (YFP) is one of the 13 global flagship species identified by the World Wildlife Fund and is classified as "Critically Endangered." It is also the only extant aquatic mammal in the Yangtze River. In this study, 44 sampling points were deployed across the middle and lower reaches of the Yangtze River, with vertical sampling sections established in four key areas. Using environmental DNA (eDNA) and species distribution model(SDM), we explored the spatiotemporal distribution of YFPs and predicted their potential suitable habitats. The results indicate that the YFP has a relatively wide distribution during the flood season but exhibits clustering behavior during the dry season, showing a patchy distribution and a migratory trend from the midstream to downstream of the main channel. Predictions using the MAXENT model reveal varying trends in suitable habitat under different scenarios. Overall, YFP's potential habitat is expected to expand by 2050, but due to rising temperatures, it will contract by 2070. Elevation (dem, 65.4%), human footprint index (hfp, 8.8%), and isothermality (bio3, 8%) are key factors influencing habitat suitability. These findings demonstrate that eDNA is an effective tool for monitoring large aquatic organisms and provide scientific evidence for the conservation of the YFP.

10.
Ecotoxicol Environ Saf ; 270: 115903, 2024 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-38176184

RESUMEN

Chlordane, a previously extensively utilized insecticidal pesticide, has since been prohibited, however, owing to its limited degradability, it continues to persist significantly in soil and water reservoirs, subsequently accumulating within plant and animal organisms, representing a substantial threat to human health. Despite extensive research conducted over the past few decades to investigate the toxic effects of chlordane, there remains a notable dearth of studies focusing on its impact on sleep activity. Therefore, in this study, the effects of short-term and long-term exposure to chlordane on the activity and sleep of Drosophila were investigated. When exposed to chlordane at a concentration of 1 µM, Drosophila lost body weight, decreased body size and resulted in lipid metabolism disorders. In addition, chlordane exposure altered the arousal and sleep behaviors of Drosophila. Short-term exposure to chlordane resulted in an increase in night-time sleep duration, while long-term exposure to chlordane resulted in an increase in activity and a decrease in sleep, as evidenced by a decrease in the duration of each sleep session and the appearance of sleep fragmentation. Under conditions of long-term chlordane exposure, reactive oxygen species levels were significantly up-regulated in Drosophila. Our results suggest that long-term chlordane exposure triggers oxidative stress damage in Drosophila, leading to sleep disruption. This study offers novel insights into the harmful impacts of environmental pollutants on human sleep patterns and proposes that mitigating the presence of chlordane in the environment could potentially contribute to the reduction of global sleep disorder prevalence.


Asunto(s)
Insecticidas , Plaguicidas , Contaminantes del Suelo , Animales , Humanos , Clordano/análisis , Drosophila/metabolismo , Contaminantes del Suelo/análisis , Insecticidas/análisis , Plaguicidas/análisis
11.
Plant Dis ; 2024 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-38916906

RESUMEN

Tobacco (Nicotiana tabacum L.) is one of the most widely cultivated industrial crops worldwide. From April to July 2023, about 40% of tobacco seedlings in the greenhouse exhibited irregular taupe lesions in Zhengzhou, Henan Province, China. At an early stage of the lesion development, light grey spots with the diameter of 1-2 mm were observed, these spots gradually expanded and connected into large irregular lesions causing leaf wrinkling or withered. A total of 12 infected leaf tissues were sterilized with 75% ethanol for 45 s, rinsed three times in sterilized water and then plated on potato dextrose agar (PDA) medium for 10 days at 28°C in darkness. Seven fungal colonies that show the similar appearance were isolated and three of them (MB-1, MB-2 and MB-3) were used for subsequent identification. Colonies of these strains on PDA with loose mycelium and orange-red pigment on the underside, white aerial in the center and light yellow hyphae near the periphery, formed in the shape of a concentric ring pattern. Ascomata appeared from the 14th day, were black, spherical or ellipsoid with walls of textura angularis, and size was 53.8-101.1 µm × 50.3-104.3 µm (n=30). Terminal hairs were brown and straight, gradually tapering toward the tips. Asci clavate or fusiform, spore bearing part 16.2-29.2 × 7.3-11.4 µm (n=21), with 8 irregularly arranged ascospores, evanescent. Ascospores are brown at maturity, biapiculate, navicular or fusiform shapes with size of 8.7-12.8 µm × 4.8-6.9 µm (n=100), and more or less inaequilateral. Single spore strains derived from these strains exhibited the morphological features consistent with the original strains. The morphological characteristics of the fungus were consistent with the description of Arcopilus aureus (Chivers) X.W. Wang & Samson (= Chaetomium aureum Chivers) (Lee et al. 2019). Furthermore, the sequences of RPB2 region were amplified from these strains and the result sequences (GenBank accession no. OR513105-OR513108) all showed a 100.00% identity with A. aureus strain CBS 538.73 (GenBank accession no. KX976807.1). It was reported that the RPB2 gene was efficient in discriminating Arcopilus species (Tavares et al. 2022), thus a maximum likelihood (ML) phylogenetic tree based on the RPB2 gene sequences were constructed using MEGA 7.0 with 1000 replications of bootstrapping (Kumar et al. 2016), which revealed that these strains formed a well-supported clade with A. aureus strains of (CBS 153.52 and CBS538.73) (Wang et al. 2022). Pathogenicity analysis were performed on healthy flue-cured tobacco seedlings leaves (cv Y85) by using mycelial agar plugs (5 mm in diameter) and spore suspension (1×106 spores/mL), and the PDA plugs and sterile water were used for control group, respectively. Tobacco seedlings were incubated in a 25°C and 70% RH growth chamber. After seven days, the leaves showed obvious symptoms, with taupe lesions and yellow halos on the periphery, whereas no symptoms were found on the control leaves. The A. aureu was then reisolated from inoculated diseased leaves. Previously, A. aureus has been only reported to cause leaf black disease on Pseudostellaria heterophylla in China (Yuan et al. 2021). To our knowledge, this is the first reported of A. aureus causing tobacco leaf grey spot worldwide. Arcopilus aureus has been reported as a plant biocontrol fungus (Wang et al. 2013). However, due to the potential serious damage in tobacco seedlings caused by this fungus, the use of A. aureus as a plant biocontrol agent needs to be given more attention, and disease control measures of this pathogen should be developed.

12.
Sensors (Basel) ; 24(18)2024 Sep 19.
Artículo en Inglés | MEDLINE | ID: mdl-39338803

RESUMEN

In dietary assessment using a single-view food image, an object of known size, such as a checkerboard, is often placed manually in the camera's view as a scale reference to estimate food volume. This traditional scale reference is inconvenient to use because of the manual placement requirement. Consequently, utensils, such as plates and bowls, have been suggested as alternative references. Although these references do not need a manual placement procedure, there is a unique challenge when a dining bowl is used as a reference. Unlike a dining plate, whose shallow shape does not usually block the view of the food, a dining bowl does obscure the food view, and its shape may not be fully observable from the single-view food image. As a result, significant errors may occur in food volume estimation due to the unknown shape of the bowl. To address this challenge, we present a novel method to premeasure both the size and shape of the empty bowl before it is used in a dietary assessment study. In our method, an image is taken with a labeled paper ruler adhered to the interior surface of the bowl, a mathematical model is developed to describe its shape and size, and then an optimization method is used to determine the bowl parameters based on the locations of observed ruler makers from the bowl image. Experimental studies were performed using both simulated and actual bowls to assess the reliability and accuracy of our bowl measurement method.


Asunto(s)
Procesamiento de Imagen Asistido por Computador , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Algoritmos , Modelos Teóricos , Dieta , Alimentos
13.
Nano Lett ; 23(16): 7733-7742, 2023 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-37379097

RESUMEN

Electrochemical reduction of nitrate to ammonia (NH3) converts an environmental pollutant to a critical nutrient. However, current electrochemical nitrate reduction operations based on monometallic and bimetallic catalysts are limited in NH3 selectivity and catalyst stability, especially in acidic environments. Meanwhile, catalysts with dispersed active sites generally exhibit a higher atomic utilization and distinct activity. Herein, we report a multielement alloy nanoparticle catalyst with dispersed Ru (Ru-MEA) with other synergistic components (Cu, Pd, Pt). Density functional theory elucidated the synergy effect of Ru-MEA than Ru, where a better reactivity (NH3 partial current density of -50.8 mA cm-2) and high NH3 faradaic efficiency (93.5%) is achieved in industrially relevant acidic wastewater. In addition, the Ru-MEA catalyst showed good stability (e.g., 19.0% decay in FENH3 in three hours). This work provides a potential systematic and efficient catalyst discovery process that integrates a data-guided catalyst design and novel catalyst synthesis for a range of applications.

14.
Angew Chem Int Ed Engl ; 63(33): e202406946, 2024 Aug 12.
Artículo en Inglés | MEDLINE | ID: mdl-38802316

RESUMEN

Control of phosphate capture and release is vital in environmental, biological, and pharmaceutical contexts. However, the binding of trivalent phosphate (PO4 3-) in water is exceptionally difficult due to its high hydration energy. Based on the anion coordination chemistry of phosphate, in this study, four charge-neutral tripodal hexaurea receptors (L1-L4), which were equipped with morpholine and polyethylene glycol terminal groups to enhance their solubility in water, were synthesized to enable the pH-triggered phosphate binding and release in aqueous solutions. Encouragingly, the receptors were found to bind PO4 3- anion in a 1 : 1 ratio via hydrogen bonds in 100 % water solutions, with L1 exhibiting the highest binding constant (1.2×103 M-1). These represent the first neutral anion ligands to bind phosphate in 100 % water and demonstrate the potential for phosphate capture and release in water through pH-triggered mechanisms, mimicking native phosphate binding proteins. Furthermore, L1 can also bind multiple bioavailable phosphate species, which may serve as model systems for probing and modulating phosphate homeostasis in biological and biomedical researches.


Asunto(s)
Aniones , Fosfatos , Agua , Fosfatos/química , Agua/química , Aniones/química , Concentración de Iones de Hidrógeno , Materiales Biomiméticos/química , Materiales Biomiméticos/metabolismo , Enlace de Hidrógeno , Estructura Molecular , Sitios de Unión
15.
BMC Genomics ; 24(1): 556, 2023 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-37730558

RESUMEN

BACKGROUND: Cocaine use (CU) is associated with psychiatric and medical diseases. Little is known about the mechanisms of CU-related comorbidities. Findings from preclinical and clinical studies have suggested that CU is associated with aberrant DNA methylation (DNAm) that may be influenced by genetic variants [i.e., methylation quantitative trait loci (meQTLs)]. In this study, we mapped cis-meQTLs for CU-associated DNAm sites (CpGs) in an HIV-positive cohort (Ntotal = 811) and extended the meQTLs to multiple traits. RESULTS: We conducted cis-meQTL analysis for 224 candidate CpGs selected for their association with CU in blood. We identified 7,101 significant meQTLs [false discovery rate (FDR) < 0.05], which mostly mapped to genes involved in immunological functions and were enriched in immune pathways. We followed up the meQTLs using phenome-wide association study and trait enrichment analyses, which revealed 9 significant traits. We tested for causal effects of CU on these 9 traits using Mendelian Randomization and found evidence that CU plays a causal role in increasing hypertension (p-value = 2.35E-08) and decreasing heel bone mineral density (p-value = 1.92E-19). CONCLUSIONS: These findings suggest that genetic variants for CU-associated DNAm have pleiotropic effects on other relevant traits and provide new insights into the causal relationships between cocaine use and these complex traits.


Asunto(s)
Cocaína , Infecciones por VIH , Humanos , Metilación de ADN , Fenotipo , Fenómica , Infecciones por VIH/genética
16.
J Am Chem Soc ; 145(33): 18221-18226, 2023 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-37552546

RESUMEN

Homochiral metal-organic macrocyclic complexes are of great significance owing to their chirality and well-defined internal cavities that potentially have the ability to mimic complicated biological processes. Here we report a novel metal/anion-coordination co-driven strategy for the formation of nanoscale supramolecular metallocycles with unique topology, large size, and desired chirality. The enantiomeric Janus-type metallocyclic strips are assembled based on the synergistic coordination of sulfate anions and CoII ions to a bifunctional achiral ligand combining the o-phenylene-(bis)urea anion-chelating and 8-hydroxyquinoline metal-coordinating sites. The inherent chirality arises from two types of helical chiralities (triply twisted Möbius ring and circular helicate), which is observed for the first time for metal-organic complex systems. Notably, spontaneous chiral resolution by conglomerate crystallization into a pair of enantiomers (P- or M-Co9) is realized, which is attributed to the multiple weak intermolecular interactions facilitating the hierarchically helical superstructure.

17.
J Am Chem Soc ; 145(32): 17643-17655, 2023 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-37540107

RESUMEN

Developing low platinum-group-metal (PGM) catalysts for the oxygen reduction reaction (ORR) in proton-exchange membrane fuel cells (PEMFCs) for heavy-duty vehicles (HDVs) remains a great challenge due to the highly demanded power density and long-term durability. This work explores the possible synergistic effect between single Mn site-rich carbon (MnSA-NC) and Pt nanoparticles, aiming to improve intrinsic activity and stability of PGM catalysts. Density functional theory (DFT) calculations predicted a strong coupling effect between Pt and MnN4 sites in the carbon support, strengthening their interactions to immobilize Pt nanoparticles during the ORR. The adjacent MnN4 sites weaken oxygen adsorption at Pt to enhance intrinsic activity. Well-dispersed Pt (2.1 nm) and ordered L12-Pt3Co nanoparticles (3.3 nm) were retained on the MnSA-NC support after indispensable high-temperature annealing up to 800 °C, suggesting enhanced thermal stability. Both PGM catalysts were thoroughly studied in membrane electrode assemblies (MEAs), showing compelling performance and durability. The Pt@MnSA-NC catalyst achieved a mass activity (MA) of 0.63 A mgPt-1 at 0.9 ViR-free and maintained 78% of its initial performance after a 30,000-cycle accelerated stress test (AST). The L12-Pt3Co@MnSA-NC catalyst accomplished a much higher MA of 0.91 A mgPt-1 and a current density of 1.63 A cm-2 at 0.7 V under traditional light-duty vehicle (LDV) H2-air conditions (150 kPaabs and 0.10 mgPt cm-2). Furthermore, the same catalyst in an HDV MEA (250 kPaabs and 0.20 mgPt cm-2) delivered 1.75 A cm-2 at 0.7 V, only losing 18% performance after 90,000 cycles of the AST, demonstrating great potential to meet the DOE targets.

18.
J Adolesc ; 95(5): 1033-1044, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-37025017

RESUMEN

INTRODUCTION: Although a few research have tried to explore the relationship between problematic smartphone use (PSU) and school engagement, most of them are limited to relatively simple correlation, and the mechanism needs to be further explored. This research focused on the relationship between PSU and school engagement/disengagement, and intended to verify two mediation paths. METHODS: We conducted two studies in 2019 at a middle school in China. 289 students (44.6% girls), aged 11-18 (Mage = 13.25, standard deviation [SD] = 1.73), participated in Study 1, a longitudinal cross-lag analysis intend to verify the relationship between PSU and school engagement/disengagement. Using a separate sample, Study 2 explored the mediating roles of academic procrastination and sleep quality. Four hundred thirty-two students aged 11-19 (42.1% girls, Mage = 16.11, SD = 1.56) participated in this cross-sectional study. In both studies, all participants completed self-report measures in classrooms during regular school hours. RESULTS: In Study 1, the results showed that PSU (T1) could significantly predict school engagement/disengagement (T2), but school engagement/disengagement (T1) could not predict PSU (T2). In Study 2, we found that academic procrastination could mediate the effect of PSU on school engagement, and sleep quality could mediate the effect of PSU on both school engagement and disengagement. CONCLUSIONS: Results highlighted that the school engagement/disengagement of adolescents can be influenced by PSU through several different ways, through which we can protect adolescents from the negative effects of PSU.


Asunto(s)
Procrastinación , Calidad del Sueño , Adolescente , Femenino , Humanos , Masculino , Estudios Transversales , Teléfono Inteligente , Estudiantes , Niño
19.
Nano Lett ; 22(1): 255-262, 2022 01 12.
Artículo en Inglés | MEDLINE | ID: mdl-34932367

RESUMEN

Chemically ordered intermetallic nanoparticles are promising candidates for energy-related applications such as electrocatalysis. However, the synthesis of intermetallics generally requires long annealing (several hours) to achieve the ordered structure, which causes nanoparticles agglomeration and diminished performance, particularly for catalysis. Herein, we demonstrate a new rapid Joule heating approach that can synthesize highly ordered and well-dispersed intermetallic nanoparticles. As a proof-of-concept, we synthesized fully ordered Pd3Pb intermetallic nanoparticles that feature small size distribution (∼6 nm). Computational analysis of the L12 Pd3Pb material suggests that this rapid atomic ordering transformation can be attributed to a vacancy-mediated diffusion mechanism. Moreover, the nanoparticles demonstrate excellent electrocatalytic activity and exceptional stability for the oxygen reduction reaction (ORR), retaining >95% of the current density over 10 h of chronoamperometry test with negligible structural and compositional changes. This study demonstrates a new strategy of providing a new direction for intermetallic synthesis and catalyst discovery.


Asunto(s)
Nanopartículas , Catálisis
20.
Int J Mol Sci ; 24(9)2023 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-37175583

RESUMEN

Acute lung injury (ALI), caused by intrapulmonary or extrapulmonary factors such as pneumonia, shock, and sepsis, eventually disrupts the alveolar-capillary barrier, resulting in diffuse pulmonary oedema and microatasis, manifested by refractory hypoxemia, and respiratory distress. Not only is ALI highly lethal, but even if a patient survives, there are also multiple sequelae. Currently, there is no better treatment than supportive care, and we urgently need to find new targets to improve ALI. Histone deacetylases (HDACs) are epigenetically important enzymes that, together with histone acetylases (HATs), regulate the acetylation levels of histones and non-histones. While HDAC inhibitors (HDACis) play a therapeutic role in cancer, inflammatory, and neurodegenerative diseases, there is also a large body of evidence suggesting the potential of HDACs as therapeutic targets in ALI. This review explores the unique mechanisms of HDACs in different cell types of ALI, including macrophages, pulmonary vascular endothelial cells (VECs), alveolar epithelial cells (AECs), and neutrophils.


Asunto(s)
Lesión Pulmonar Aguda , Células Endoteliales , Humanos , Células Endoteliales/metabolismo , Histona Desacetilasas/metabolismo , Pulmón/metabolismo , Lesión Pulmonar Aguda/tratamiento farmacológico , Lesión Pulmonar Aguda/metabolismo , Células Epiteliales Alveolares/metabolismo , Inhibidores de Histona Desacetilasas/farmacología , Inhibidores de Histona Desacetilasas/uso terapéutico , Inhibidores de Histona Desacetilasas/metabolismo
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