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As China faces demographic shifts and socioeconomic changes, the burden of Alzheimer's disease (AD) and associated cognitive impairments is increasing dramatically, with significant implications for public health and the economy. This systematic review and meta-analysis aims to provide a comprehensive assessment of the prevalence and incidence of AD across China. Drawing from an extensive search of international and Chinese databases up to August 27, 2023, including PubMed, Embase, and the Cochrane Library, we synthesized data from 105 studies. Our analysis reveals a combined prevalence of AD of 3.48% within a sample of 626,276 elderly individuals and an incidence rate of 7.90 per 1000 person-years. Subgroup and meta-regression analyses highlight age and gender as pivotal factors influencing these epidemiological patterns. Notably, significant heterogeneity exists due to variations in diagnostic criteria and study quality, impacting the comparability of findings. This meta-analysis underscores the need for continued research into demographic and modifiable risk factors influencing AD, while emphasizing standardized reporting practices to address these limitations and improve the understanding of AD's challenge in China.
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Alzheimer Disease , Humans , Alzheimer Disease/epidemiology , China/epidemiology , Prevalence , Incidence , Risk Factors , Female , Male , AgedABSTRACT
BACKGROUND: Previous studies have demonstrated associations between fatty acids and neurological disorders. However, no studies have examined the relationship between serum fatty acid levels and serum neurofilament light chain (NfL), a biomarker of neurological disorders. OBJECTIVES: This study aimed to comprehensively investigate the intricate relationship between 30 serum fatty acids and serum NfL levels in a nationally representative sample of United States adults, using data from the 2013-2014 National Health and Nutrition Examination Survey. METHODS: Using a cross-sectional analysis, multivariable linear regression models were used to explore the associations between 30 serum fatty acids and serum NfL levels. This analysis involved adjustment for potential confounding variables, including age, sex, race, body mass index (BMI), smoking status, hyperlipidemia, and diabetes, to clarify the association between serum fatty acids and serum NfL levels. RESULTS: The analysis revealed that certain fatty acids exhibited distinct associations with serum NfL levels. Notably, docosanoic acid (22:0) and tricosanoic acid (C23:0) were found to be inversely associated with serum NfL levels (ß = -0.280, 95% confidence interval [CI]: -0.525, -0.035; ß = -0.292, 95% CI: -0.511, -0.072). Conversely, palmitoleic acid (16:1n-7) demonstrated a positive association with serum NfL levels (ß = 0.125, 95% CI: 0.027, 0.222). Notably, these associations remained significant even after adjustment for potential confounders. CONCLUSIONS: Individuals with high relative concentrations of certain SFA exhibited decreased serum NfL, whereas those with high relative concentrations of certain monounsaturated fatty acids showed increased serum NfL. These findings contribute to a deeper understanding of the potential impact of serum fatty acids on NfL levels, shedding light on novel avenues for further investigation and potential interventions in the context of neurological health.
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BACKGROUND: The soluble triggering receptor expressed on myeloid cells 2 (sTREM2) in cerebrospinal fluid (CSF) is considered a biomarker of microglia activity. The objective of this study was to investigate the trajectory of CSF sTREM2 levels over time and examine its association with sex. METHODS: A total of 1,017 participants from the Alzheimer's Disease Neuroimaging Initiative Study (ADNI) with at least one CSF sTREM2 record were included. The trajectory of CSF sTREM2 was analyzed using a growth curve model. The association between CSF sTREM2 levels and sex was assessed using linear mixed-effect models. RESULTS: CSF sTREM2 levels were increased with age over time (P < 0.0001). No significant sex difference was observed in sTREM2 levels across the entire sample; however, among the APOE ε4 allele carriers, women exhibited significantly higher sTREM2 levels than men (ß = 0.146, P = 0.002). CONCLUSION: Our findings highlight the association between CSF sTREM2 levels and age-related increments, underscoring the potential influence of aging on sTREM2 dynamics. Furthermore, our observations indicate a noteworthy association between sex and CSF sTREM2 levels, particularly in individuals carrying the APOE ε4 allele.
Subject(s)
Alzheimer Disease , Biomarkers , Membrane Glycoproteins , Neuroimaging , Receptors, Immunologic , Humans , Alzheimer Disease/cerebrospinal fluid , Alzheimer Disease/diagnostic imaging , Female , Male , Membrane Glycoproteins/cerebrospinal fluid , Membrane Glycoproteins/genetics , Receptors, Immunologic/genetics , Aged , Longitudinal Studies , Neuroimaging/methods , Biomarkers/cerebrospinal fluid , Aged, 80 and over , Apolipoprotein E4/genetics , Aging/cerebrospinal fluid , Sex Characteristics , Middle AgedABSTRACT
PURPOSE: The analysis of long-term trends of mortality from epilepsy has not been conducted, which is crucial for estimating the future burden of epilepsy. We therefore aimed to investigate the long-term trends of mortality from epilepsy in the United States from 1979 to 2021. METHODS: The cause-of-death and demographic data were from the National Center for Health Statistics (1979-2021) and population estimates were from the US Census Bureau. We used the joinpoint regression model to analyze secular trends in the mortality of epilepsy spanning from 1979 to 2021. Age-adjusted mortality from epilepsy was assessed based on the year 2000 U.S. population data, stratified by age, sex, and race. RESULTS: The age-adjusted mortality from epilepsy increased from 0.78 per 100,000 population in 1979 to 1.01 per 100,000 population in 2021, with an average annual percent change (AAPC) of 0.58% (95% confidence interval [CI]: 0.45% - 0.72%). The overall age-adjusted mortality of epilepsy had been on the rise between 2011 and 2021. The mortality rate generally increases with age. The mortality of epilepsy was higher in the Afro-American people and men. The mortality of epilepsy in both sexes declined first and then increased, with AAPC 1.02% (95% CI: 0.88%, 1.23%) in women and 0.10% (95% CI: -0.002%, 0.21%) in men. Mortality in all races including White, Afro-American people, and other races individuals fell first and then rose. The AAPC of mortality in White, other races, and Afro-American people were 0.89% (95% CI: 0.79%, 1.02%), -0.87% (95% CI: -1.84%, 0.88%), and -0.31% (95% CI: -0.48%, -0.13%), respectively. CONCLUSION: Although the mortality rate from epilepsy has experienced a period of decline, it is worth noting that the last decade has seen a rapid increase. A comprehensive assessment of long-term trends in mortality from epilepsy holds significance for healthcare prioritization.
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Epilepsy , Humans , Epilepsy/mortality , United States/epidemiology , Male , Female , Middle Aged , Adult , Aged , Young Adult , Adolescent , Child , Aged, 80 and over , Mortality/trends , Child, Preschool , Infant , Age FactorsABSTRACT
BACKGROUND: Previous studies have suggested a connection between impaired olfactory function and an increased risk of rapid eye movement sleep behavior disorder (RBD) in individuals diagnosed with Parkinson's disease (PD). However, there is a gap in knowledge regarding the potential impact of olfactory dysfunction on the long-term patterns of sleep disorders among early PD patients. METHODS: Data from the Parkinson's Progression Markers Initiative program included 589 participants with assessments of sleep disorders using the Epworth Sleepiness Scale (ESS) and RBD Screening Questionnaire (RBDSQ). Olfactory dysfunction at baseline was measured using the University of Pennsylvania Smell Identification Test. Trajectories of sleep disorders over a 5-year follow-up were identified using group-based trajectory modeling, and the relationship between olfactory dysfunction and sleep disorder trajectories was examined through binomial logistic regression. RESULTS: Two distinct trajectories of sleep disorders over the 5-year follow-up period were identified, characterized by maintaining a low or high ESS score and a low or high RBDSQ score. An inversion association was observed between olfactory function measures and trajectories of excessive daytime sleepiness (odds ratio [OR] = 0.97, 95% confidence interval [CI] 0.95, 1.00, p = 0.038), after controlling for potential covariates. Similarly, olfactory function showed a significant association with lower trajectories of probable RBD (OR = 0.96, 95% CI 0.94, 0.98, p = 0.001) among early PD individuals. Consistent findings were replicated across alternative analytical models. CONCLUSIONS: Our findings indicated that olfactory dysfunction was associated with unfavorable long-term trajectories of sleep disorders among early PD.
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OBJECTIVE: To investigate the characteristics of beta parapapillary atrophy (ß-PPA) in patients with primary angle-closure suspect (PACS). METHODS AND ANALYSIS: In total, 215 and 259 eyes with PACS and non-PACS (NPACS), respectively, were enrolled in this observational, cross-sectional study. Stereoscopic fundus and optical coherence tomography images were used to characterise ß-PPA; the former was also used to measure the major ß-PPA parameters. Univariate and multiple logistic regression analyses were used to identify the factors correlated with the presence of ß-PPA and with ß-PPA parameters. RESULTS: The ß-PPA occurrence rates were 48.80% and 44.40% in the PACS and NPACS groups, respectively, with no significant difference between groups. Compared with that in the NPACS group, the ß-PPA area was significantly larger (p=0.005) in the PACS group, but the angular extent and maximum radial length did not differ between groups (p=0.110 and 0.657, respectively) after adjusting for age and axial length. The presence of ß-PPA was associated with older age (OR 1.057, 95% CI 1.028 to 1.088, p<0.001) and larger disc area (OR 1.716, 95% CI 1.170 to 2.517, p=0.006). A larger ß-PPA area was associated with older age (p=0.014), greater vertical cup-to-disc ratio (p=0.028), larger disc area (p<0.001) and PACS diagnosis (p=0.035). CONCLUSION: 48.80% of participants with PACS had ß-PPA, which is slightly larger than NPACS. The area of ß-PPA was larger in PACS, while the angular extent and maximum radial length did not differ between groups.
Subject(s)
Eye Diseases, Hereditary , Glaucoma, Open-Angle , Optic Atrophy , Optic Disk , Humans , Optic Disk/pathology , Glaucoma, Open-Angle/complications , Optic Atrophy/complications , Cross-Sectional Studies , Intraocular Pressure , Visual Fields , Atrophy/complicationsABSTRACT
Electrochemical C-N coupling reaction based on carbon dioxide and nitrate have been emerged as a new "green synthetic strategy" for the synthesis of urea, but the catalytic efficiency is seriously restricted by the inherent scaling relations of adsorption energies of the active sites, the improvement of catalytic activity is frequently accompanied by the decrease in selectivity. Herein, a doping engineering strategy was proposed to break the scaling relationship of intermediate binding and minimize the kinetic barrier of C-N coupling. A thus designed SrCo0.39Ru0.61O3-δ catalyst achieves a urea yield rate of 1522â µg h-1 mgcat. -1 and faradic efficiency of 34.1 % at -0.7â V versus reversible hydrogen electrode. A series of characterizations revealed that Co doping not only induces lattice distortion but also creates rich oxygen vacancies (OV) in the SrRuO3. The oxygen vacancies weaken the adsorption of *CO and *NH2 intermediates on the Co and Ru sites respectively, and the strain effects over the Co-Ru dual sites promoting the occurrence of C-N coupling of the two monomers instead of selective hydrogenating to form by-products. This work presents an insight into molecular coupling reactions towards urea synthesis via the doping engineering on SrRuO3.
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OBJECTIVE: This study aimed to investigate the associations between exposure to blood volatile organic compounds (VOCs) and the level of serum neurofilament light chain (NfL) in adults. METHODS: We analyzed data from the 2013-2014 National Health and Nutrition Examination Survey (NHANES), including 2008 participants aged 20 to 75 years old. Multiple linear regression models were used to examine the associations between 28 VOCs and NfL after adjusting for multiple potential confounders. Restricted cubic spline (RCS) was used to examine the potential non-linear associations. RESULTS: The linear regression models showed that higher levels of 2,5-dimethylfuran (ß = 0.042, 95 % confidence interval [CI]: 0.001, 0.096), ethyl acetate (ß = 0.118, 95 % CI = 0.008, 0.304), and m-/p-xylene (ß = 0.043, 95%CI = 0.012, 0.074) were associated with higher NfL levels. These estimates were largely consistent after adjusting for multiple confounders. CONCLUSION: The findings of our study suggest a potential association between certain volatile organic compounds (2,5-dimethylfuran, ethyl acetate, and m-/p-xylene) and blood NfL levels, implying that they may have a role in revealing neurodegeneration and influencing neurological health.
Subject(s)
Acetates , Volatile Organic Compounds , Xylenes , Adult , Aged , Humans , Middle Aged , Young Adult , Biomarkers , Nutrition Surveys , Volatile Organic Compounds/blood , Volatile Organic Compounds/toxicity , Neurofilament Proteins/bloodABSTRACT
A new strategy that can effectively increase the nitrogen reduction reaction performance of catalysts is proposed and verified by tuning the coordination number of metal atoms. It is found that the intrinsic activity of Mn atoms in the manganese borides (MnBx) increases in tandem with their coordination number with B atoms. Electron-deficient boron atoms are capable of accepting electrons from Mn atoms, which enhances the adsorption of N2 on the Mn catalytic sites (*) and the hydrogenation of N2 to form *NNH intermediates. Furthermore, the increase in coordination number reduces the charge density of Mn atoms at the Fermi level, which facilitates the desorption of ammonia from the catalyst surface. Notably, the MnB4 compound with a Mn coordination number of up to 12 exhibits a high ammonia yield rate (74.9 ± 2.1 µg h-1 mgcat -1) and Faradaic efficiency (38.5 ± 2.7%) at -0.3 V versus reversible hydrogen electrode (RHE) in a 0.1 m Li2SO4 electrolyte, exceeding those reported for other boron-related catalysts.
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OBJECTIVE: To examine the associations of excessive daytime sleepiness (EDS) and probable rapid eye movement sleep behavior disorder (pRBD), respectively, with impulsive-compulsive behaviors (ICBs) over a 5-year follow-up in patients with early Parkinson's disease (PD). METHODS: The Parkinson's Progression Markers Initiative is a multicenter cohort study based on an ongoing and open-ended registry. Longitudinal associations of sleep disorders with ICB over 5-year follow-up visits were estimated using generalized linear mixed-effects models among PD participants. RESULTS: A total of 825 PD participants were enrolled at baseline. The study sample had a median baseline age of 63.1 (interquartile range: 55.6-69.3) years and comprised 496 (61.5%) men. Among them, 201 (24.9%) had ICB at baseline. In the generalized mixed-effects models, EDS (odds ratio [OR] = 1.09, 95% confidence interval [CI] 1.05, 1.12) and RBD (OR = 1.07, 95% CI 1.03, 1.12) were substantially associated with higher odds of developing ICB over time in PD patients, after multivariate adjustment including age, gender, family history, GDS score, STAI-Y score, MDS-UPDRS part III score, LEDD, and disease duration. Consistent results were observed when stratifying by age at baseline, gender, and PD family history. CONCLUSIONS: The study findings suggest a longitudinal association between EDS and pRBD with an increased risk of developing ICB in patients with PD. The findings emphasize the significance of evaluating and addressing sleep disorders in PD patients as a potential approach to managing ICB.
Subject(s)
Parkinson Disease , Humans , Male , Female , Parkinson Disease/epidemiology , Parkinson Disease/complications , Parkinson Disease/psychology , Middle Aged , Aged , Prospective Studies , REM Sleep Behavior Disorder/epidemiology , REM Sleep Behavior Disorder/complications , Sleep Wake Disorders/epidemiology , Compulsive Behavior/epidemiology , Impulsive Behavior , Disorders of Excessive Somnolence/epidemiology , Cohort StudiesABSTRACT
To examine the association between cytomegalovirus (CMV) seropositivity and all-cause mortality in a nationwide cohort of US adults. We obtained data from the National Health and Nutrition Examination Survey III (1988-1994), including 16,547 participants aged 18-90 years old with CMV serology assessments. Mortality status was ascertained until December 2019 using the National Death Index linkage data. The Cox proportional hazard model was applied to estimate the association between CMV seropositivity and mortality. During a median follow-up of 26.3 years, 6,930 deaths were recorded. CMV seropositivity was associated with a higher hazard of all-cause mortality after adjusting for attained age, sex, and ethnicity (HR: 1.22, 95% CI: 1.10, 1.36, p < 0.001). The magnitude of the association attenuated slightly after adjusting further for body mass index, family income, smoking status, diabetes, and self-reported cancer history (HR = 1.11, 95% CI: 1.00, 1.23, p = 0.04). While the association was observed for both men and women, it was only statistically significant among non-Hispanic white people (HR: 1.16, 95% CI: 1.06, 1.26, p = 0.001) but not among other ethnic populations. CMV seropositivity might be an independent risk factor for all-cause mortality among US adults. If the findings are validated in an independent population, further research is needed to unveil the biological mechanisms driving the increased mortality with CMV seropositivity.
Subject(s)
Cytomegalovirus Infections , Cytomegalovirus , Adult , Male , Humans , Female , Adolescent , Young Adult , Middle Aged , Aged , Aged, 80 and over , Cohort Studies , Cytomegalovirus Infections/complications , Cytomegalovirus Infections/epidemiology , Nutrition Surveys , Prospective StudiesABSTRACT
The aim of this study was to evaluate the associations between psychological resilience and epigenetic clocks assessed by DNA methylation age predictions. We used data from 4018 participants in the Health and Retirement Study. Multivariable linear regression models were used to estimate the association between psychological resilience and epigenetic clocks adjusted for age, sex, race, body mass index, smoking status, and years of education. Thirteen epigenetic clocks were used in our analysis and were highly correlated with one another. A higher psychological resilience score was associated with slower DNA methylation age acceleration for the majority of epigenetic clocks after multivariable adjustment. These findings imply that people with a higher level of psychological resilience may experience slower DNA methylation age acceleration and biological aging.
Subject(s)
Epigenesis, Genetic , Resilience, Psychological , Humans , Retirement , DNA Methylation , Aging/geneticsABSTRACT
Non-noble metal oxides have emerged as potential candidate electrocatalysts for acidic oxygen evolution reactions (OERs) due to their earth abundance; however, improving their catalytic activity and stability simultaneously in strong acidic electrolytes is still a major challenge. In this work, we report Co3O4@carbon core-shell nanoparticles on 2D graphite sheets (Co3O4@C-GS) as mixed-dimensional hybrid electrocatalysts for acidic OER. The obtained Co3O4@C-GS catalyst exhibits a low overpotential of 350 mV and maintains stability for 20 h at a current density of 10 mA cm-2 in H2SO4 (pH = 1) electrolyte. X-ray photoelectron and X-ray absorption spectroscopies illustrate that the higher content of Co3+ sites boosts acidic OER. Operando Raman spectroscopy reveals that the catalytic stability of Co3O4@C nanoparticles during the acidic OER is enhanced by the introduction of graphite sheets. This interface engineering of non-noble metal sites with high valence states provides an efficient approach to boost the catalytic activity and enhance the stability of noble-metal-free electrocatalysts for acidic OER.
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PURPOSE: In a nationwide cohort of US adults, an exploration of the association between cytomegalovirus (CMV) infection and cancerrelated mortality was conducted. MATERIALS AND METHODS: We acquired data from the National Health and Nutrition Examination Survey III (1988-1994), including 11,138 individuals who were aged 18-90 years at enrollment and underwent CMV serology assessments. CMV infection was determined by CMV antibody testing. Cancerrelated mortality status was ascertained until December 2019 utilizing the National Death Index linkage data and determined by neoplasms. The Cox proportional hazard model was applied to estimate the potential association between CMV infection and the risk of cancer-related mortality. RESULTS: During a median follow-up of 26.1 years, 1514 cancerrelated deaths were identified in the study cohort. After adjusting for age, sex, and ethnicity, CMV infection was associated with a higher hazard of cancerrelated mortality (hazard ratio [HR]: 1.39, 95 % CI: 1.13, 1.70). Further adjustments for body mass index, family income, and smoking status slightly attenuated the magnitude of the association (HR: 1.24, 95 % CI: 1.00, 1.53). However, no significant interaction was observed among gender by subgroup analysis. CONCLUSIONS: CMV infection might be an independent risk factor for cancerrelated mortality among US adults. Future studies could focus on the mechanisms through which CMV infection influences mortality induced by neoplasms and develop targeted interventions to reduce the risk.
Subject(s)
Cytomegalovirus Infections , Neoplasms , Adult , Humans , Cytomegalovirus , Nutrition Surveys , Cytomegalovirus Infections/complications , Cytomegalovirus Infections/epidemiology , Risk FactorsABSTRACT
Background: Microcystin-leucine-arginine (MC-LR) is the most abundant and most toxic variant of microcystin isomers. Various experiments have clearly shown that MC-LR has hepatotoxicity and carcinogenicity, but there are relatively few studies on its immune damage effect. In addition, numerous studies have shown that microRNAs (miRNAs) are involved in a wide range of biological processes. Do miRNAs also play a role in inflammatory response caused by microcystin exposure? This is the question to be answered in this study. Moreover, this study can also provides experimental evidence for the significance of miRNA applications. Objective: To investigate the effect of MC-LR on the expressions of miR-146a and pro/anti-inflammatory cytokines in human peripheral blood mononuclear cells (PBMCs) and to further explore the role of miR-146a in the inflammatory responses caused by MC-LR. Methods: Serum samples from 1789 medical examiners were collected and detect the concentrations of MCs, and 30 serum samples with concentrations of MCs around P25, P50, and p75 were randomly selected for the detection of inflammatory factors. PBMCs from fresh peripheral blood extracted from these 90 medical examiners were subsequently tested for relative miR-146a expression. In vitro, the MC-LR were exposed to the PBMCs to detect the levels of inflammatory factors as well as the relative expression of miR-146a-5p. Then, a miRNA transfection assay was performed to verify the regulation of inflammatory factors by miR-146a-5p. Results: In population samples, the expression of inflammatory factors and miR-146a-5p increased with increasing MCs concentration. In vitro experiments showed that the expression of inflammatory factors and miR-146a-5p in PBMCs increased with MC-LR exposure time or exposure dose too. In addition, inhibiting the expression of miR-146a-5p in PBMCs reduced inflammatory factor levels. Conclusion: miR-146a-5p exerts a promoting effect on the MC-LR-induced inflammatory response by positively regulating inflammatory factor levels.
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Purpose: To investigate whether the retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) change with optic nerve head (ONH) size in healthy eyes. Methods: This cross-sectional observational study recruited participants aged ≥50 years. Participants underwent optical coherence tomography-assisted measurements of the peripapillary RNFL and macular GCC and were divided into small, medium, and large ONH groups according to optic disc area (≤1.9 mm2, >1.9 mm2 and ≤2.4 mm2, and >2.4 mm2, respectively). The groups were compared for RNFL and GCC. Linear regression models were used to evaluate the correlation of RNFL and GCC with ocular and systemic factors. Results: There were 366 participants. The whole, temporal, and superior RNFLs were significantly different among the groups (P = 0.035, 0.034, and 0.013, respectively) with no significant difference in the nasal and inferior RNFL (P = 0.214, 0.267, respectively). The average, superior, and inferior GCCs were not significantly different among the groups (P = 0.583, 0.467, and 0.820, respectively). Thinner RNFL was independently associated with older age (P = 0.003), male sex (P = 0.018), smaller disc area (P < 0.001), higher vertical cup disc ratio (VCDR) (P < 0.001), and larger maximum cup depth (P = 0.007); thinner GCC was independently associated with older age (P = 0.018), larger best-corrected visual acuity (P = 0.023), and higher VCDR (P = 0.002). Conclusions: RNFL but not GCC significantly increased with ONH size in healthy eyes. GCC may be more suitable than RNFL for evaluating early glaucoma in patients with large or small ONH. Translational Relevance: GCC may be a better index than RNFL for early glaucoma evaluation in patients with large or small ONH.
Subject(s)
Glaucoma , Optic Disk , Humans , Male , Optic Disk/diagnostic imaging , Cross-Sectional Studies , Retinal Ganglion Cells , Nerve Fibers , Tomography, Optical CoherenceABSTRACT
The Martian atmospheric waves perturbation Datasets (MAWPD) version 2.0 is the first observation-based climatology dataset of Martian atmospheric waves. It contains climatology-gridded temperature, gravity waves, and tides spanning the whole Martian year. MAWPD uses the Data INterpolating Empirical Orthogonal Functions method (DINEOF) reconstruction method for data assimilation with the observational data from the Mars Global Surveyor (MGS), Mars Reconnaissance Orbiter (MRO), Mars Atmosphere and Volatile EvolutioN (MAVEN), Mars Pathfinder (MP), Mars Phoenix Lander (MPL), Mars Exploration Rover (MER) and Mars Express (MEX) temperature retrievals. The dataset includes gridded fields of temperature (Level 1 data) as well as the physical quantities of GWs (Level 2 data, amplitude, and potential energies), SPWs and tides (Level 2 data, amplitude, and phase). The MAWPD, based entirely on multiple reliable observations, provides climatological background atmospheric information of temperature and wave disturbances on Mars. The dataset is not only useful for observation-based scientific studies concerning Martian atmospheric waves, e.g., circulation, dust storms, and wave excitation mechanism, but also for cross-validating with model-based datasets or model results.
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We report Ca2-xIrO4 nanocrystals exhibit record stability of 300 h continuous operation and high iridium mass activity (248 A gIr-1 at 1.5 VRHE) that is about 62 times that of benchmark IrO2. Lattice-resolution images and surface-sensitive spectroscopies demonstrate the Ir-rich surface layer (evolved from one-dimensional connected edge-sharing [IrO6] octahedrons) with high relative content of Ir5+ sites, which is responsible for the high activity and long-term stability. Combining operando infrared spectroscopy with X-ray absorption spectroscopy, we report the first direct observation of key intermediates absorbing at 946 cm-1 (Ir6+âO site) and absorbing at 870 cm-1 (Ir6+OO- site) on iridium-based oxides electrocatalysts, and further discover the Ir6+âO and Ir6+OO- intermediates are stable even just from 1.3 VRHE. Density functional theory calculations indicate the catalytic activity of Ca2IrO4 is enhanced remarkably after surface Ca leaching, and suggest IrOO- and IrâO intermediates can be stabilized on positive charged active sites of Ir-rich surface layer.
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Tuning the local reaction environment is an important and challenging issue for determining electrochemical performances. Herein, we propose a strategy of intentionally engineering the local reaction environment to yield highly active catalysts. Taking Ptδ- nanoparticles supported on oxygen vacancy enriched MgO nanosheets as a prototypical example, we have successfully created a local acid-like environment in the alkaline medium and achieve excellent hydrogen evolution reaction performances. The local acid-like environment is evidenced by operando Raman, synchrotron radiation infrared and X-ray absorption spectroscopy that observes a key H3O+ intermediate emergence on the surface of MgO and accumulation around Ptδ- sites during electrocatalysis. Further analysis confirms that the critical factors of the forming the local acid-like environment include: the oxygen vacancy enriched MgO facilitates H2O dissociation to generate H3O+ species; the F centers of MgO transfers its unpaired electrons to Pt, leading to the formation of electron-enriched Ptδ- species; positively charged H3O+ migrates to negatively charged Ptδ- and accumulates around Ptδ- nanoparticles due to the electrostatic attraction, thus creating a local acidic environment in the alkaline medium.
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Ru-incorporated Co3O4 nanoparticles have been synthesized from self-sacrificial ZIF-67 template and utilized as efficient electrocatalysts towards oxygen reduction and evolution reactions (ORR and OER). Amongst, Ru@Co3O4-1.0 exhibited the optimum electrocatalytic behavior with an ultra-low potential gap (0.84 V) between the OER potential (1.61 V at 10 mA cm-2) and ORR half-wave potential (0.77 V). The zinc-air battery using Ru@Co3O4-1.0 as a cathode presented high specific capacity (788.1 mAh g-1) and power density (101.2 mW cm-2). Meanwhile, this battery possessed relatively lower voltage gap and higher cycling stability compared with the commercial Pt/C-based one. Ruthenium incorporation induced remarkable lattice expansion of Co3O4 and engineered more oxygen vacancies, promoting the lattice oxygen mobility from the subsurface/bulk phase onto surface. All these properties were recognized to be the crucial parameters for electrocatalytic activity improvement. This work provided a facile approach to design highly active metal oxide with broad potentiality for rechargeable metal-air batteries.