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•Nanopore regulation strategy can improve the sodium storage capacity of hard carbon.•The relationship between nanopore and sodium storage capability was investigated.•Micropores ...hardly accommodate Na+ ions and hinder Na+ ion diffusion.•Mesopores facilitate Na+ ion intercalation and shorten the ion diffusion pathway.
Hard carbon is regarded as one of the most promising anode material for sodium-ion batteries in virtue of the low cost and stable framework. However, the correlation between pore structures of hard carbon and sodium-ion storage is still ambiguous. In this work, based on precise control of pore-size distribution, the capacity, ion diffusion, and initial Coulombic efficiency were improved. Meanwhile, the relationship between pore structure and capacity was investigated. Our result indicates that the micropores hinder ion diffusion and hardly ever accommodate Na+ ions, while mesopores facilitate Na+ ion intercalation. Hard carbon with negligible micropores and abundant mesopores delivers a maximum capacity of 283.7 mAh g−1 at 20 mA g−1, which is 83% higher than that of micropore-rich one. Even after 320 cycles at 200 mA g−1, the capacity still remains 189.4 mAh g−1.
Exploring high-activity and earth-abundant electrocatalysts for electrochemical reactions, including the hydrogen evolution reaction (HER), oxygen reduction reaction (ORR) and oxygen evolution ...reaction (OER), etc. are crucial for building future large-scale green energy conversion and storage systems. Recently, some low-cost and resourceful two-dimensional (2D) semiconductor materials such as transition metal dichalcogenides (TMDCs) and layered oxides, have attracted increasing attention in electrocatalysis applications in virtue of their comparable catalytic activity and long-term stability to conventional noble metal-based catalysts (e.g. Pt/C, RuO2, IrO2, etc.). However, the intrinsic activity of some 2D materials still cannot meet the increasing requirement for highly efficient and reliable eletrocatalysts for future energy conversion and storage systems. In this context, designing elctrocatalysts with sufficient amount of active sites accessible for electrolyte, high activity of each active sites, and excellent conductivity is of great significance. To this end, defect engineering is a powerful strategy for tailoring the physical and chemical properties of 2D materials for efficient electrocatalysis. In this article, an overview of recent progress on defect engineering in 2D eletrocatalysts for HER, ORR and OER is presented. The effects of defects on the structure and tuned properties of 2D materials in eletrocatalysts applications are also summarized. Additionally, the challenges and opportunities ahead in this emerging field are also proposed.
This review article summarizes the recent progress on defect engineering of 2D materials for improved electrocatalytic activity towards hydrogen evolution reaction (HER), oxygen reduced reaction (ORR) and oxygen evolution reaction (OER). Display omitted
•2D materials are attractive to serve as noble-metal-free electrocatalysts for HER, ORR and OER.•Defect engineering can enhance catalytic activity of 2D elctrocatalysts.•Recent progress on defect engineering of two-dimensional 2D eletrocatalysts for HER, ORR and OER are summarized.•Challenges and opportunities of defect engineering for electrocatalysts are proposed.
Trans sodium crocetinate (TSC) has been reported to exert a protective effect against cerebral ischemia/reperfusion (I/R) injury. However, whether TSC protects against myocardial ischemia/reperfusion ...(MI/R) injury remains unknown. Herein, we found that TSC treatment reduced myocardial infract size and elevated serum LDH and CK activities of MI/R rats. TSC administration attenuated oxidative stress in MI/R rats and H9C2 cells exposed to oxygen glucose deprivation/reperfusion (OGD/R). TSC administration relieved I/R-induced myocardial apoptosis in vivo and in vitro, as evidenced by reduced number of TUNEL positive cells, accompanying with marked decreases in caspase-3 activity and Bax protein level and an increase in Bcl-2 protein level. TSC treatment markedly increased SIRT3 activity and SIRT3 and SOD2 protein levels, and could also diminished the phosphorylation of FOXO3a protein. Additionally, TSC treatment attenuated the acetylation of FOXO3a and SOD2 protein. But, these effects were obviously blocked by SIRT3 knockdown. Besides, SIRT3 knockdown blocked the cardioprotective effect of TSC on OGD/R-induced oxidative stress, apoptosis and mitochondrial dysfunction in vitro. In summary, TSC alleviates I/R-induced myocardial oxidative stress and apoptosis via the SIRT3/FOXO3a/SOD2 signaling pathway. Our study suggests that TSC may become a novel drug for the treatment of MI/R injury.
•Trans sodium crocetinate (TSC) treatment alleviated MI/R injury.•TSC administration attenuated cell injury in vivo and in vitro.•SIRT3 knockdown blocked the cardioprotective effects of TSC.•TSC alleviates I/R-induced cell injury via the SIRT3/FOXO3a/SOD2 signaling.
The rechargeable Zn–air batteries as an environmentally friendly sustainable energy technology have been extensively studied. However, it is still a challenge to develop non-noble metal bifunctional ...catalysts with high oxygen reduction as well as oxygen evolution reaction (ORR and OER) activity and superior durability, which limit the large-scale application of rechargeable Zn–air batteries. Herein, we synthesized an ultrastable FeCo bifunctional oxygen electrocatalyst on Se-doped CNTs (FeCo/Se-CNT) via a gravity guided chemical vapor deposition (CVD) strategy. The catalyst exhibits excellent ORR (E 1/2 = 0.9 V) and OER (overpotential at 10 mA cm–2 = 340 mV) properties simultaneously, surpassing commercial Pt/C and RuO2/C catalysts. More importantly, the catalyst shows an unordinary stability, that is, is no obvious decrease after 30K cycles accelerated durability test for ORR and OER processes. The small potential gap (0.75 V) represents superior bifunctional ORR and OER activities of the FeCo/Se-CNT catalyst. The FeCo/Se-CNT catalyst possesses outstanding electrochemical performance for the rechargeable liquid and flexible all-solid-state Zn–air batteries, for example, a high open circuit voltage (OCV) and peak power density of 1.543 and 1.405 V and 173.4 and 37.5 mW cm–2, respectively.
This paper investigates connectedness in option implied moments, such as volatility, skewness, and kurtosis across precious metals (gold, silver) and energy (crude oil and natural gas) markets in ...both time and frequency domains. Using daily option data from January 4, 2010, to December 31, 2020, we first construct implied moments and then examine their static and dynamic connectedness via time-frequency spillover methods and network analysis. The results show that system-wide connectedness weakens as the moment order becomes higher, and the level of spillovers in all implied moments is much higher at a lower frequency. The spillovers show substantial time variation and pronounced intensity during turbulent periods. Gold is the net transmitter in precious metals and energy markets. However, if excluding the crisis period in 2020, crude oil and gold play dominant roles. Further analysis shows the main drivers of the spillover indices for the higher-order moments. Our findings have important implications for commodity traders and investors, risk managers, and policymakers.
•Construct implied higher-order moments for gold, silver, oil, and natural gas.•Study dynamic spillovers via time-frequency methods and network analysis.•Spillovers are higher at lower frequency and weaken as the moment order increases.•Gold is the net transmitter in all three estimators in this system.•Crude oil shifts from net transmitter to net recipient during crisis period.
Highway platooning of vehicles has been identified as a promising framework in developing intelligent transportation systems. By autonomous or semi-autonomous vehicle control and intervehicle ...coordination, an appropriately managed platoon can potentially offer enhanced safety, improved highway utility, increased fuel economy, and reduced emissions. This paper is focused on quantitative characterization of the impact of communication information structures and contents on platoon safety. By comparing different information structures that combine front sensors, rear sensors, and wireless communication channels, as well as different information contents such as distances, speeds, and drivers' actions, we reveal a number of intrinsic relationships between vehicle coordination and communications in platoons. Typical communication standards and related communication latency are used as benchmark cases in this paper. The findings of this paper provide useful guidelines in sensor selections, communication resource allocations, and vehicle coordination.
The coordinated configuration of atomic platinum (Pt) has always been identified as an active site with high intrinsic activity for hydrogen evolution reaction (HER). Herein, we purposely synthesize ...single vacancies in a carbon matrix (defective graphene) that can trap atomic Pt to form the Pt–C3 configuration, which gives exceptionally high reactivity for HER in both acidic and alkaline solutions. The intrinsic activity of Pt–C3 site is valued with a turnover frequency (TOF) of 26.41 s–1 and mass activity of 26.05 A g–1 at 100 mV, respectively, which are both nearly 18 times higher than those of commercial 20 wt % Pt/C. It is revealed that the optimal coordination Pt–C3 has a stronger electron-capture ability and lower Gibbs free energy difference (ΔG), resulting in promoting the reduction of adsorbed H+ and the acceleration of H2 desorption, thus exhibiting the extraordinary HER activity. This work provides a new insight on the unique coordinated configuration of dispersive atomic Pt in defective C matrix for superior HER performance.
The unprecedented outbreak and continuous spread of the COVID-19 virus starting in December 2019 resulted in a strict lockdown and nationwide long-term home isolation, which has possibly led to ...increased levels of family violence in China. This commentary aims to explore two issues related to the impacts of the COVID-19 pandemic on family violence in China, with intimate partner violence as its most common form. These two issues are whether the COVID-19 pandemic has indeed had a negative impact on family violence and, if so, what its specific influences upon family violence in China have been. This commentary is largely descriptive and based upon previously published literature and public statistical reports from newspaper, government, and criminal justice sources on family violence during the COVID-19 pandemic in China. Despite the lack of relevant and accurate nationwide statistics on family violence in China, multiple reports seem to suggest that family violence has surged during the COVID-19 pandemic. This increase in family violence may be primarily due to the large-scale lockdown that aggravates family conflicts, economic distress and tension caused by the pandemic among family members, and inadequate support for victims of family violence during the pandemic. Family violence has become an important social issue that needs to be dealt properly and swiftly during the ongoing COVID-19 pandemic. Both governmental and non-governmental organizations (NGOs), as well as agencies and service sectors, need to be aware of the needs of family violence victims and provide appropriate and immediate assistance to the victims during the pandemic. A detailed discussion of the policy implications and suggestions for future research are provided at the end of this commentary.
The diagnostic and prognostic significance of carcinoembryonic antigen (CEA), carbohydrate associated antigen 19-9 (CA19-9), alpha-fetoprotein (AFP) and cancer antigen 125 (CA125) in early gastric ...cancer have not been investigated yet. Thus, the present study aimed to explore the diagnostic and prognostic significance of the four tumor markers for early gastric cancer.
From September 2008 to March 2015, 587 early gastric cancer patients were given radical gastrectomy in our center. The clinicopathological characteristics were recorded. The association between levels of CEA and CA19-9 and clinicopathological characteristics and prognosis of patients were analyzed.
There were 444 men (75.6%) and 143 women (24.4%). The median age was 57 years (ranged 21-85). The 1-, 3- and 5-year overall survival rate was 99.1%, 96.8% and 93.1%, respectively. The positive rate of CEA, CA19-9, AFP and CA125 was 4.3%, 4.8%, 1.5% and 1.9%, respectively. The positive rate of all markers combined was 10.4%. The associations between the clinicopathological features and levels of CEA and CA19-9 were analyzed. No significant association was found between CEA level and clinicopathological features. However, elevated CA19-9 level was correlated with female gender and presence of lymph node metastasis. Age > 60 years old, presence of lymph node metastasis and elevation of CEA level were independent risk factors for poor prognosis of early gastric cancer.
The positive rates of CEA, CA19-9, APF and CA125 were relatively low for early gastric cancer. Elevation of CA19-9 level was associated with female gender and presence of lymph node metastasis. Elevation of CEA level was an independent risk factor for the poor prognosis of early gastric cancer.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Chordoma, as a rare, low-grade malignant tumor that tends to occur in the midline of the body, grows slowly but often severely invades surrounding tissues and bones. Due to the severe invasion and ...damage to the surrounding tissues, chordoma is difficult to be gross totally resected in surgery, and the progression of the residual tumor is often unavoidable. Besides, the tumor is insensitive to conventional radiotherapy and chemotherapy, thus finding effective treatment methods for chordoma is urgent. Nowadays, immunotherapy has made a series of breakthroughs and shown good therapeutic effects in kinds of tumors, which brings new insights into tumors without effective treatment strategies. With the deepening of research on immunotherapy, some studies focused on the immune microenvironment of chordoma have been published, most of them concentrated on the infiltration of immune cells, the expression of tumor-specific antigen or the immune checkpoint expression. On this basis, a series of immunotherapy studies of chordoma are under way, some of which have shown encouraging results. In this review, we reviewed the research about immune microenvironment and immunotherapy for chordoma, combined with the existing clinical trials data, hoping to clarify the frontiers and limitations of chordoma immune research, and provide reference for follow-up immunotherapy research on chordoma.
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