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1.
Neurosci Biobehav Rev ; : 105810, 2024 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-39009293

RESUMEN

Sleep disturbances, encompassing altered sleep physiology or disorders like insomnia and sleep apnea, profoundly impact physiological functions and elevate disease risk. Despite extensive research, the underlying mechanisms and sex-specific differences in sleep disorders remain elusive. While polysomnography serves as a cornerstone for human sleep studies, animal models provide invaluable insights into sleep mechanisms. However, the availability of animal models of sleep disorders is limited, with each model often representing a specific sleep issue or mechanism. Therefore, selecting appropriate animal models for sleep research is critical. Given the significant sex differences in sleep patterns and disorders, incorporating both male and female subjects in studies is essential for uncovering sex-specific mechanisms with clinical relevance. This review provides a comprehensive overview of various rodent models of sleep disturbance, including sleep deprivation, sleep fragmentation, and circadian rhythm dysfunction. We evaluate the advantages and disadvantages of each model and discuss sex differences in sleep and sleep disorders, along with potential mechanisms. We aim to advance our understanding of sleep disorders and facilitate sex-specific interventions.

3.
Med Phys ; 2024 Jun 06.
Artículo en Inglés | MEDLINE | ID: mdl-38843522

RESUMEN

BACKGROUND: Cirrhosis patients often exhibit clinical symptoms such as right liver atrophy, portal hypertension, spleen enlargement and increased blood supply, which exhibit considerable variation between the left and right liver sections. These differences are hypothesized to stem from disparities in blood flow within the left and right portal vein (PV) branches. However, rigorous quantitative evidence remains scarce. PURPOSE: We mainly aim at quantitatively revealing the relationship between the blood flow rates of two PV branches and liver volumes, and providing quantitative evidence and theoretical support for the diagnosis and treatment of cirrhosis from the perspective of hemodynamics. METHODS: Five cirrhotic patients and two healthy volunteers from Beijing Friendship Hospital are investigated. Their PV blood flow models are established based on computed tomography (CT) images and finite volume simulations. The volume of the left and right liver lobes are measured in 3-matic. The distributions of blood source in the PV branches are tracked by streamline analysis. The blood flow rates are quantitatively counted by integrating the blood source velocities. Linear analysis is performed to build the relationship between liver volumes and PV blood flow distributions. RESULTS: Streamline analysis reveals significant differences in blood distribution between the left and right PV branches. The majority of blood from the superior mesenteric vein (SMV) flowed into the right portal vein (RPV), while most blood from the splenic vein (SV) entered the left portal vein (LPV). The main PV pressure drop linearly increases with the SV blood velocity for all PV structures of patients and healthy volunteers. The flow rate ratio QRPV/QLPV demonstrates an increase in tandem with the volume ratio VR/VL, exhibiting a linear correlation with the Pearson correlation coefficient being 0.93. CONCLUSION: The differences in the blood distributions are consistent with the clinicians' knowledge and validate our simulations. We demonstrated a linear increase in PV pressure with elevated SV blood velocity. Additionally, the volumes of the left and right hepatic lobes exhibited a positive correlation with blood flow rates in the corresponding PV branches.

4.
Molecules ; 29(12)2024 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-38930930

RESUMEN

Considering that heavy-metal contamination of seawater is getting worse, building a quick, accurate and portable device for detecting trace zinc in seawater in real time would be very beneficial. In this work, a microfluidic system was developed that includes a planar disc electrode, a micro-cavity for detection, an electrochemical workstation, a computer, a container for waste liquid reprocessing, an external pipeline and other components as well as a graphene/cerium oxide/nano-cerium oxide/Nafion composite membrane was used to modify the planar disc electrode (GR/CeO2/Nafion/Au) to investigate the electrochemical behaviour of Zn(II) using cyclic voltammetry, square-wave voltammetry and orthogonal test methods. Under optimal experimental conditions, the peak reaction current of Zn(II) showed a good linear relationship with the concentration of Zn(II) in the range of 1-900 µg/L with a correlation coefficient of 0.998, and the detection limit of the method was 0.87 µg/L. In addition, the microfluidic system had good stability, reproducibility and anti-interference. The system was used for determining zinc ions in real seawater samples, and the results were very similar to those of inductively coupled plasma-emission spectrometry, demonstrating the practicality of the system for the detection of trace zinc.

5.
ACS Omega ; 9(22): 23843-23852, 2024 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-38854572

RESUMEN

The stability of both the structure and activity of MoS2 nanocatalysts is crucial for minimizing the catalyst cost of the slurry-phase (SP) catalytic hydrogenation. MoS2-GP and MoS2-SP catalysts were, respectively, obtained by gas-phase (denoted as GP) and SP aging of fresh MoS2 catalysts. The MoS2-SP catalyst demonstrated a comparable catalytic hydrogenation activity to that of the fresh MoS2 catalyst, which is about 1.7 times of that for the MoS2-GP catalyst. After 12 cycles of the MoS2-SP catalyst, the obtained Cy12 catalyst demonstrates a retention of 92.0% of its initial catalytic activity. The MoS2-SP catalyst exhibits an impressive stability of catalytic hydrogenation. The MoS2-SP catalyst exhibits average stacking layers of 3.3 and an average slab of 5.2 nm and exposes 14.0% of active sites. The MoS2-SP catalyst can serve as a highly active and stable catalyst for catalytic hydrogenation. This finding can offer valuable insights into the stability of the hydrogenation catalyst in SP hydrogenation technology.

6.
Nano Lett ; 24(25): 7593-7600, 2024 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-38869928

RESUMEN

In traditional optical wireless communication (OWC) systems, the simultaneous use of multiple sets of light-emitting diodes (LEDs) and photodetectors (PDs) increases the system complexity and instability. Here we report bifunctional light-emitting photodetectors (LEPDs) fabricated with quasi-2D perovskite (F-PEA)2Cs4Pb5I11Br5 as light-emitting/detecting layers for efficient, miniaturized, and intelligent bidirectional OWC. By simply changing the solvent composition of the precursor solution and using antisolvent engineering, we manipulated the crystal orientation and phase distribution of (F-PEA)2Cs4Pb5I11Br5, realizing high irradiance (4.36 µW cm-2) and a -3 dB refresh rate (0.21 MHz) of electroluminescence in LED mode as well as low noise (below 1 pA Hz-1/2) and high responsivity (0.1 A W-1) in PD mode. The rapid and accurate OWC process was demonstrated through interaction of LEPDs. We also demonstrated the high-fidelity compression and digitization of high-resolution (256 × 256 pixels) color images using the four-step phase shift method to realize intelligent encrypted image OWC.

7.
Int J Biol Macromol ; : 133328, 2024 Jun 29.
Artículo en Inglés | MEDLINE | ID: mdl-38945702

RESUMEN

Alginate (Alg) as co-extruded casing is of interest to the meat industry as replacers for natural sausage casing. However, these studies on the mechanical reinforcement of Alg-based film are still limited in the wet state (e.g. co-extrusion process). In this work, Alg-D with the highest viscosity-average molecular weight (1.12 × 105) was selected from four types of alginates based on the results of the viscosity of Alg solutions and film strength. Next, three celluloses (cellulose nanocrystals (CNC), cellulose nanofibers (CNF) and microfibrillated fiber (MFC)) were added to the Alg-D matrix at different concentrations. SEM showed that the cross section of the Alg-based films became more compact and uniform when the size of celluloses decreased. The tensile test revealed that the strength (TS) of Alg-based films exhibited an initial increase followed by a subsequent drop as the cellulose content rose. The best mechanical strengthening effect was the Alg-CNC film (1.16 MPa), which increased by 93.33 % compared with that of pure Alg. Cooking treatment could further enhance this trend. The opacity increased gradually with the increase of cellulose content, while these films were still transparent enough for food packaging. These findings would have potential applications in food packaging, especially co-extruded sausage casings.

8.
Science ; 384(6696): 670-676, 2024 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-38723074

RESUMEN

Electrochemistry offers a sustainable synthesis route to value-added fine chemicals but is often constrained by competing electron transfer between the electrode and redox-sensitive functionalities distinct from the target site. Here, we describe an ion-shielding heterogeneous photoelectrocatalysis strategy to impose mass-transfer limitations that invert the thermodynamically determined order of electron transfer. This strategy is showcased to enable decarboxylative trifluoromethylation of sensitive (hetero)arenes by using trifluoroacetate, an inexpensive yet relatively inert trifluoromethyl group (CF3) source. An ion-shielding layer, formed by trifluoroacetate anions electrostatically adsorbed on a positive molybdenum-doped tungsten trioxide (WO3) photoanode, prevents undesired electron transfer between substrates and photogenerated holes. The practicality of the developed method was demonstrated with robust photoanode stability (approximately 380 hours), a good substrate scope, and scaling capability to achieve 100-gram synthesis by using photoelectrochemical flow cells.

9.
Eur J Med Chem ; 272: 116463, 2024 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-38704944

RESUMEN

Butyrylcholinesterase (BChE) has attracted wide interest as a promising target in Alzheimer's disease (AD) investigation. BChE is considered to play a compensable role of hydrolyzing acetylcholine (ACh), and its positive correlation with ß-amyloid (Aß) deposition also promotes disease progression. Herein, we uncovered a selective potent BChE inhibitor S21-1011 (eqBChE IC50 = 0.059 ± 0.006 µM, hBChE IC50 = 0.162 ± 0.069 µM), which presented satisfactory druggability and therapeutic efficacy in AD models. In pharmacokinetics (PK) studies, S21-1011 showed excellent blood-brain barrier (BBB) permeability, metabolism stability and high oral-bioavailability. In pharmacodynamic (PD) studies, it protected neural cells from toxicity and inflammation stimulation in vitro. Besides, it also exerted anti-inflammatory effect and alleviated cognitive impairment in mice models induced by lipopolysaccharides (LPS) and Aß. Generally, this compound has been confirmed to function as a neuroprotector and cognition improver in various AD pathology-like models. Therefore, S21-1011, a novel potent BChE inhibitor, could be considered as a potential anti-AD candidate worthy of more profound investigation.


Asunto(s)
Enfermedad de Alzheimer , Butirilcolinesterasa , Inhibidores de la Colinesterasa , Quinolinas , Butirilcolinesterasa/metabolismo , Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/metabolismo , Animales , Inhibidores de la Colinesterasa/farmacología , Inhibidores de la Colinesterasa/química , Inhibidores de la Colinesterasa/síntesis química , Ratones , Humanos , Relación Estructura-Actividad , Quinolinas/química , Quinolinas/farmacología , Quinolinas/síntesis química , Descubrimiento de Drogas , Estructura Molecular , Masculino , Lipopolisacáridos/farmacología , Lipopolisacáridos/antagonistas & inhibidores , Relación Dosis-Respuesta a Droga , Fármacos Neuroprotectores/farmacología , Fármacos Neuroprotectores/química , Fármacos Neuroprotectores/síntesis química , Piperazinas/farmacología , Piperazinas/química , Piperazinas/síntesis química , Péptidos beta-Amiloides/antagonistas & inhibidores , Péptidos beta-Amiloides/metabolismo , Antiinflamatorios/farmacología , Antiinflamatorios/química , Antiinflamatorios/síntesis química , Inflamación/tratamiento farmacológico , Barrera Hematoencefálica/metabolismo , Barrera Hematoencefálica/efectos de los fármacos
10.
Asian J Psychiatr ; 97: 104088, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38810490

RESUMEN

INTRODUCTION: Suicide attempts (SA) are a significant contributor to suicide deaths, and non-suicidal self-injury (NSSI) can increase the risk of SA. Many adolescents experience both NSSI and SA, which are affected by various factors. This study aimed to identify the risk factors and essential warning signs of SA, establish a predictive model for SA using multiple dimensions and large samples, and provide a multidimensional perspective for clinical diagnosis and intervention. METHODS: A total of 9140 participants aged 12-18 years participated in an online survey; 6959 participants were included in the statistical analysis. A multilayer perceptron algorithm was used to establish a prediction model for adolescent SA (with or without); adolescents with NSSI behavior were extracted as a subgroup to establish a prediction model. RESULTS: Both the prediction model performance of the SA group and the NSSI-SA subgroup were strong, with high accuracy, and AUC values of 0.93 and 0.88, indicating good discrimination. Decision curve analysis (DCA) demonstrated that the clinical intervention value of the prediction results was high and that the clinical intervention benefits of the NSSI-SA subgroup were greater than those of the SA group. CONCLUSIONS: Our study demonstrated that the predictive model has a high degree of accuracy and discrimination, thereby identifying significant factors associated with adolescent SA. As long as adolescents exhibit NSSI behavior, relative suicide interventions should be implemented to prevent future hazards. This study can provide guidance and more nuanced insights for clinical diagnosis as well as a foundation for clinical treatment.


Asunto(s)
Conducta Autodestructiva , Intento de Suicidio , Humanos , Adolescente , Conducta Autodestructiva/epidemiología , Femenino , Intento de Suicidio/estadística & datos numéricos , Masculino , Niño , China/epidemiología , Redes Neurales de la Computación , Conducta del Adolescente , Factores de Riesgo , Pueblos del Este de Asia
11.
Cell Oncol (Dordr) ; 2024 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-38607517

RESUMEN

PURPOSE: GPX8, which is found in the endoplasmic reticulum lumen, is a member of the Glutathione Peroxidases (GPXs) family. Its role in hepatocellular carcinoma (HCC) is unknown. METHODS: Immunohistochemical staining was used to detect the protein levels of GPX8 in HCC tissue microarrays. A short hairpin RNA lentivirus was used to knock down GPX8, and the main signaling pathways were investigated using transcriptome sequencing and a phosphorylated kinase array. The sphere formation assays, cloning-formation assays and cell migration assays were used to evaluate the stemness and migration ability of HCC cells. Identifying the GPX8-interacting proteins was accomplished through immunoprecipitation and protein mass spectrometry. RESULTS: The GPX8 protein levels were downregulated in HCC patients. Low expression of GPX8 protein was related to early recurrence and poor prognosis in HCC patients. GPX8 knockdown could enhance the stemness and migration ability of HCC cells. Consistently, Based on transcriptome analysis, multiple signaling pathways that include the PI3K-AKT and signaling pathways that regulate the pluripotency of stem cells, were activated after GPX8 knockdown. The downregulation of GPX8 could increase the expression of the tumor stemness markers KLF4, OCT4, and CD133. The in vivo downregulation of GPX8 could also promote the subcutaneous tumor-forming and migration ability of HCC cells. MK-2206, which is a small-molecule inhibitor of AKT, could reverse the tumor-promoting effects both in vivo and in vitro. We discovered that GPX8 and the 71-kDa heat shock cognate protein (Hsc70) have a direct interaction. The phosphorylation of AKT encouraged the translocation of Hsc70 into the nucleus and the expression of the PI3K p110 subunit, thereby increasing the downregulation of GPX8. CONCLUSION: The findings from this study demonstrate the anticancer activity of GPX8 in HCC by inactivating the Hsc70/AKT pathway. The results suggest a possible therapeutic target for HCC.

12.
Appl Neuropsychol Adult ; : 1-10, 2024 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-38648268

RESUMEN

PURPOSE: To evaluate the reliability and validity of a newly developed computerized Automated Battery of Cognitive Tests in healthy individuals without cognitive impairments or psychiatric disorders. METHODS: From April 20 to July 1, 2023, 142 healthy individuals in Beijing and Tangshan, China were assessed using the Automated Battery of Cognitive Tests. After a 3-week interval, 36 participants were randomly selected for retesting. The assessment also included administration of the Repeatable Battery for the Assessment of Neuropsychological Status and the Automated Battery of Cognitive Tests to 59 participants. RESULTS: The Automated Battery of Cognitive Tests consists of 16 subtests. Internal consistency reliability was 0.75. The test-retest reliability for each factor ranged from 0.337 to 0.850 (p < 0.05). The criterion-related validity, as measured by correlation with the total Repeatable Battery for the Assessment of Neuropsychological Status score, was 0.748 (p < 0.001). The cumulative variance contribution rate is 70.109%. The results of the confirmatory factor analysis indicated a good model fit. CONCLUSIONS: The computerized Automated Battery of Cognitive Tests is a cognitive self-assessment tool with good reliability and validity. It can evaluate multiple aspects of cognitive performance in healthy individuals and is suitable for self-administration through remote access via Internet.

13.
Proc Natl Acad Sci U S A ; 121(16): e2319119121, 2024 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-38588435

RESUMEN

The advancement of atomically precise dinuclear heterogeneous catalysts holds great potential in achieving efficient catalytic ozonation performance and contributes to the understanding of synergy mechanisms during reaction conditions. Herein, we demonstrate a "ship-in-a-bottle and pyrolysis" strategy that utilizes Fe2(CO)9 dinuclear-cluster to precisely construct Fe2 site, consisting of two Fe1-N3 units connected by Fe-Fe bonds and firmly bonded to N-doped carbon. Systematic characterizations and theoretical modeling reveal that the Fe-Fe coordination motif markedly reduced the devotion of the antibonding state in the Fe-O bond because of the strong orbital coupling interaction of dual Fe d-d orbitals. This facilitates O-O covalent bond cleavage of O3 and enhances binding strength with reaction intermediates (atomic oxygen species; *O and *OO), thus boosting catalytic ozonation performance. As a result, Fe dinuclear site catalyst exhibits 100% ozonation efficiency for CH3SH elimination, outperforming commercial MnO2 catalysts by 1,200-fold. This research provides insights into the atomic-level structure-activity relationship of ozonation catalysts and extends the use of dinuclear catalysts in catalytic ozonation and beyond.

14.
Am J Transplant ; 2024 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-38642712

RESUMEN

Immune checkpoint inhibitors (ICIs) as a downstaging or bridging therapy for liver transplantation (LT) in hepatocellular carcinoma patients are rapidly increasing. However, the evidence about the feasibility and safety of pre-LT ICI therapy is limited and controversial. To this end, a multicenter, retrospective cohort study was conducted in 11 Chinese centers. The results showed that 83 recipients received pre-LT ICI therapy during the study period. The median post-LT follow-up was 8.1 (interquartile range 3.3-14.6) months. During the short follow-up, 23 (27.7%) recipients developed allograft rejection, and 7 of them (30.4%) were diagnosed by liver biopsy. Multivariate logistics regression analysis showed that the time interval between the last administration of ICI therapy and LT (TLAT) ≥ 30 days was an independent protective factor for allograft rejection (odds ratio = 0.096, 95% confidence interval 0.026-0.357; P < .001). Multivariate Cox analysis showed that allograft rejection was an independent risk factor for overall survival (hazard ratio = 9.960, 95% confidence interval 1.006-98.610; P = .043). We conclude that patients who receive a pre-LT ICI therapy with a TLAT shorter than 30 days have a much higher risk of allograft rejection than those with a TLAT longer than 30 days. The presence of rejection episodes might be associated with higher post-LT mortality.

15.
Cardiovasc Pathol ; 71: 107648, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38649123

RESUMEN

This case report presents a 20-year-old male patient initially diagnosed with infective endocarditis, later correctly identified as Behçet's syndrome. The patient's complex clinical presentation, including chest pain, aortic dilation, severe aortic regurgitation, and aortic root abscess, posed significant diagnostic and therapeutic challenges. Despite initial misdiagnosis and treatment difficulties, the patient's condition significantly improved with appropriate immunosuppressive therapy, underscoring the potential for successful management of this complex condition. This case serves as a valuable reminder of the diagnostic challenges posed by Behçet's syndrome and the importance of considering this condition in patients presenting with symptoms suggestive of infective endocarditis.


Asunto(s)
Síndrome de Behçet , Errores Diagnósticos , Inmunosupresores , Humanos , Síndrome de Behçet/diagnóstico , Síndrome de Behçet/tratamiento farmacológico , Masculino , Adulto Joven , Inmunosupresores/uso terapéutico , Endocarditis/diagnóstico , Endocarditis/terapia , Endocarditis/tratamiento farmacológico , Resultado del Tratamiento , Diagnóstico Diferencial , Insuficiencia de la Válvula Aórtica/cirugía , Insuficiencia de la Válvula Aórtica/diagnóstico , Insuficiencia de la Válvula Aórtica/etiología , Valor Predictivo de las Pruebas
16.
Cardiovasc Pathol ; 71: 107651, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38679299

RESUMEN

BACKGROUND: This study aimed to explore the clinical and pathological features of aortitis in China, which is a rare disease that is often overlooked preoperatively. METHODS: We reviewed the records of 2950 patients who underwent aortic surgery at Wuhan Asia General Hospital from 2016 to 2023. Clinical and pathological data were collected and compared across different groups. RESULTS: Out of 2950 patients, 15 had healed aortitis, 2 were healed Takayasu aortitis (TAK), and 13 were not further classified. Forty-two had active aortitis, including clinically isolated aortitis ([CIA], 42.9%), infectious aortitis ([IA], 26.2%), TAK (16.7%), and Behçet's syndrome ([BS], 14.3%), half of these cases were not recognized preoperatively. All patients who developed perivalvular leakage during follow-up had concurrent non-infectious valvulitis with mixed inflammatory pattern at the time of initial surgery. Seventeen out of 18 patients with CIA survived without complications, as did 8 out of 11 patients with IA, 6 out of 7 patients with TAK, and 2 out of 6 patients with BS. CONCLUSIONS: Half of the aortitis cases were initially diagnosed by pathologists. Noninfectious valvulitis with mixed inflammatory pattern is a risk factor for perivalvular leakage. BS is associated with a higher rate of complications. Patients with CIA have a good prognosis in China, which is different from the West.


Asunto(s)
Aortitis , Arteritis de Takayasu , Humanos , Masculino , Femenino , China/epidemiología , Persona de Mediana Edad , Adulto , Aortitis/patología , Aortitis/epidemiología , Aortitis/cirugía , Arteritis de Takayasu/epidemiología , Arteritis de Takayasu/patología , Arteritis de Takayasu/complicaciones , Estudios Retrospectivos , Anciano , Adulto Joven , Síndrome de Behçet/complicaciones , Síndrome de Behçet/patología , Síndrome de Behçet/epidemiología , Síndrome de Behçet/diagnóstico , Factores de Riesgo , Valor Predictivo de las Pruebas , Resultado del Tratamiento , Aorta/patología , Aorta/cirugía , Adolescente , Pronóstico , Pueblos del Este de Asia
17.
Acta Pharmacol Sin ; 2024 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-38671193

RESUMEN

Despite the widespread prevalence and important medical impact of insomnia, effective agents with few side effects are lacking in clinics. This is most likely due to relatively poor understanding of the etiology and pathophysiology of insomnia, and the lack of appropriate animal models for screening new compounds. As the main homeostatic, circadian, and neurochemical modulations of sleep remain essentially similar between humans and rodents, rodent models are often used to elucidate the mechanisms of insomnia and to develop novel therapeutic targets. In this article, we focus on several rodent models of insomnia induced by stress, diseases, drugs, disruption of the circadian clock, and other means such as genetic manipulation of specific neuronal activity, respectively, which could be used to screen for novel hypnotics. Moreover, important advantages and constraints of some animal models are discussed. Finally, this review highlights that the rodent models of insomnia may play a crucial role in novel drug development to optimize the management of insomnia.

18.
Materials (Basel) ; 17(3)2024 Jan 24.
Artículo en Inglés | MEDLINE | ID: mdl-38591377

RESUMEN

The determination of the electrochemically active surface area (ECSA) of a catalyst layer (CL) of a non-precious metal catalyst is of fundamental importance in optimizing the design of a durable CL for anion exchange membrane (AEM) water electrolysis, but has yet to be developed. Traditional double layer capacitance (Cdl), measured by cyclic voltammetry (CV), is not suitable for the estimation of the ECSA due to the nonconductive nature of Ni-based oxides and hydroxides in the non-Faradaic region. This paper analyses the applicability of electrochemical impedance spectroscopy (EIS) compared to CV in determining capacitances for the estimation of the ECSA of AEM-based CLs in an aqueous KOH electrolyte solution. A porous electrode transmission line (TML) model was employed to obtain the capacitance-voltage dependence from 1.0 V to 1.5 V at 20 mV intervals, covering both non-Faradic and Faradic regions. This allows for the identification of the contribution of a NiFe-layered double hydroxide (LDH) catalyst and supports in a CL, to capacitances in both non-Faradic and Faradic regions. A nearly constant double layer capacitance (Qdl) observed in the non-Faradic region represents the interfaces between catalyst supports and electrolytes. The capacitance determined in the Faradic region by EIS experiences a peak capacitance (QF), which represents the maximum achievable ECSA in an AEMCL during reactions. The EIS method was additionally validated in durability testing. An approximate 30% loss of QF was noted while Qdl remained unchanged following an eight-week test at 1 A/cm2 constant current density, implying that QF, determined by EIS, is sensitive to and therefore suitable for assessing the loss of ECSA. This universal method can provide a reasonable estimate of catalyst utilization and enable the monitoring of catalyst degradation in CLs, in particular in liquid alkaline electrolyte water electrolysis systems.

19.
Angew Chem Int Ed Engl ; 63(27): e202403463, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38661020

RESUMEN

Metal sulfide (MS) is regarded as a promising candidate of the anode materials for sodium-ion battery (SIB) with ideal capacity and low cost, yet still suffers from the inferior cycling stability and voltage degradation. Herein, the coordination relationship between the discharge product Na2S with the Na+ (NaPF6) in the electrolyte, is revealed as the root cause for the cycling failure of MS. Na+-coordination effect assistants the dissolution of Na2S, further delocalizing Na2S from the reaction interface under the function of electric field, which leads to the solo oxidation of the discharge product element metal without the participation of Na2S. Besides, the higher highest occupied molecular orbital of Na2S suggest the facilitated Na2S solo oxidation to produce sodium polysulfides (NaPSs). Based on these, lowering the Na+ concentration of the electrolyte is proposed as a potential improvement strategy to change the coordination environment of Na2S, suppressing the side reactions of the solo-oxidation of element metal and Na2S. Consequently, the enhanced conversion reaction reversibility and prolonged cycle life are achieved. This work renders in-depth perception of failure mechanism and inspiration for realizing advanced conversion-type anode.

20.
Small ; : e2311879, 2024 Mar 10.
Artículo en Inglés | MEDLINE | ID: mdl-38461527

RESUMEN

Carbon-defect engineering in single-atom metal-nitrogen-carbon (M─N─C) catalysts by straightforward and robust strategy, enhancing their catalytic activity for volatile organic compounds, and uncovering the carbon vacancy-catalytic activity relationship are meaningful but challenging. In this study, an iron-nitrogen-carbon (Fe─N─C) catalyst is intentionally designed through a carbon-thermal-diffusion strategy, exposing extensively the carbon-defective Fe─N4 sites within a micro-mesoporous carbon matrix. The optimization of Fe─N4 sites results in exceptional catalytic ozonation efficiency, surpassing that of intact Fe─N4 sites and commercial MnO2 by 10 and 312 times, respectively. Theoretical calculations and experimental data demonstrated that carbon-defect engineering induces selective cleavage of C─N bond neighboring the Fe─N4 motif. This induces an increase in non-uniform charges and Fermi density, leading to elevated energy levels at the center of Fe d-band. Compared to the intact atomic configuration, carbon-defective Fe─N4 site is more activated to strengthen the interaction with O3 and weaken the O─O bond, thereby reducing the barriers for highly active surface atomic oxygen (*O/*OO), ultimately achieving efficient oxidation of CH3 SH and its intermediates. This research not only offers a viable approach to enhance the catalytic ozonation activity of M─N─C but also advances the fundamental comprehension of how periphery carbon environment influences the characteristics and efficacy of M─N4 sites.

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