•The Co-Ta3N5 catalysts were successfully prepared by in situ confined growth of active catalytic species within porous nanofilm using Ta3N5 as templates.•The Co-Ta3N5 nanohybrid is a cheap and ...earth-abundant bifunctional electrocatalyst for OER and HER.•The Co-Ta3N5 can exhibit outstanding catalytic HER in a wide range of pH media.•The Co-Ta3N5 catalyst exhibited outstanding electrochemical stability.•The outstanding HER and OER catalytic performance of Co-Ta3N5-800 has surpassed that of most current cobalt-containing catalysts.
The abundant water resources from the earth are natural feedstocks for the electrolysis of water to produce hydrogen, and there is an urgent need for an efficient and stable catalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Exploration of noble-metal-free, highly-efficient and durable bifunctional catalysts for HER and OER remains a challenge. In this work, Co-Ta3N5 catalysts were successfully prepared by in situ confined growth of active catalytic species within porous nanofilm using three-dimensional (3D) tantalum nitride (Ta3N5) porous nanofilm as templates. After electrochemical testing, we found that Co-Ta3N5 nanohybrid exhibits excellent OER and HER performance. Benefiting from the 3D composite nanostructures, the catalysts have excellent electron conduction rates and sufficient active sites, the Co-Ta3N5 nanocomposites nitrided at 800 °C exhibits relatively good catalytic activity for HER in acidic (low overpotential of 59.1 mV at 10 mA cm−2, small Tafel slope of 58 mV dec−1) and alkaline (low overpotential of 93 mV at 10 mA cm−2, Tafel slope of 97 mV dec−1) media, respectively. Co-Ta3N5-800 also exhibits relatively good catalytic activity for OER with low overpotentials 358 mV at 10 mA cm−1 in 1M KOH and the Tafel slope of 58.5 mV dec−1. Additionally, Co-Ta3N5-800 possesses excellent catalytic performance, and its catalytic performance with almost no degradation in catalytic performance after severe electrochemical tests, which ascribe to the structure of cobalt nanoparticles that confined-growth in Ta3N5 nanotubes. This discovery may pave a new avenue toward the development of robust inexpensive electrocatalysts for OER and HER.
The COVID-19 pandemic has negatively impacted mental health throughout our society. Despite this, studies report that vaping among teens and young adults has decreased during the pandemic. This paper ...aims to analyze why COVID-19 impacted vaping in such a way and if that change will remain consistent as we head toward the end of the pandemic. Additionally, using PubMed and Google Scholar, we examined the different mental and physical effects of vaping and what that means for the future. Studies from the early stages of the pandemic show vaping rates among teens and young adults to be decreasing due to health concerns. However, as people become less concerned about COVID-19, vaping rates have begun to increase. The potential future health effects are unknown and need to be evaluated further.
Adolescents face pressure from their school studies and college admissions, which results in them constantly experiencing symptoms of stress, anxiety, and depression. These symptoms cause sleep ...quality and concentration to rapidly corrode, which affects their overall mental health. These symptoms have increased in severity as the COVID-19 pandemic progressed, and if left unattended, they will last for a long period, even during post-covid. For the purpose of finding a practical way to combat these effects caused in general, the impacts of practicing Tai Chi on adolescents' general and mental health, as well as the potential underlying mechanisms involved were systematically reviewed through the last 20 years of research. This review provides information on the efficacy of overall health, feasibility, and fundamental knowledge of the practice of Tai Chi. This information could be considered by schools when planning their curriculum and mental health management to support adolescents during and after the pandemic.
Fe:Ti:Al2O3 single crystals were successfully grown by the floating zone (FZ) method in different atmospheres. The grown crystals, typically about 7–8mm in diameter and 50–70mm in length, have been ...obtained from the materials of Al2O3 doped with FeTiO3 and Fe2O3. The effect of the atmosphere on the growth was studied, and the obtained single crystals presented the best crystal quality when grown in argon. The optimum growth parameters by the FZ method for this single crystal were also studied in order to grow the highest quality single crystal. The crystal has been characterized by means of X-ray diffraction (XRD) and X-ray single crystal diffraction. Meanwhile, the Raman spectroscopy indicates that the single crystal grown in argon is similar to the natural blue sapphire. The transmittance was also measured by ultraviolet and visible spectrophotometry. Coloration mechanism in the single crystals of Fe:Ti:Al2O3 was analyzed by an electron probe X-ray microanalyser (EPMA). It is proved that iron is the main coloring element.
•Floating zone growth of Fe:Ti:Al2O3 single crystals in different atmospheres.•The crystal growth procedure and the best growth conditions are well characterized.•The 646cm−1 Raman peak is the evidence similar to the natural blue sapphire.•The EPMA proves that iron is the main coloring element.•The transmittance analysis exhibits high transmission (higher than 60% in argon).
PE is a multifactorial gestational complication affecting 4.6% of pregnancies worldwide.1 It is the top cause of prenatal morbidity/mortality and is associated with a high incidence of maternal and ...perinatal complications, causing a heavy burden to the healthcare system.1 The aetiology of PE is associated with defective trophoblast differentiation and functions causing abnormal placental development, insufficient placental perfusion, and maternal–foetal exchange defects.1,2 Our limited knowledge of the pathogenesis of the disease has hindered the development of a reliable approach for the prediction and treatment of PE. ...renal damage including glomerular capillary endotheliosis and glomerular erythropenia (Figure 1I) and deterioration of development in terms of placental diameter and thickness, biparietal diameter, crown-rump length and foetal heart rate (Figure 1J) were observed in the knockdown mice. Suppression of CD147 functions by functional blocking antibody8 (Table S1) and siRNA (Figure S5) or stimulation of CD147 by ligation antibody9 (Table S1) showed that trophoblastic CD147 regulated characteristic features of the vascular remodelling process in early human pregnancy, including EVCT invasiveness and MMP2 expression/activity (Figure 3A,B), integration of EVCT into the endothelial network (Figure 3C), and endothelial cell angiogenesis (Figure 3D) and permeability (Figure 3E).
Placental choriocarcinoma, a reproductive system carcinoma in women, has about 0.81% occurrence frequency in China, which leads to over 90% lethality due to indistinct pathogenesis and the absence of ...efficient therapeutic treatment. In the present study, using immunostaining and reverse transcription PCR, we reported that Dickkopf-1 (Dkk-1) is prominently expressed in human cytotrophoblast (CTB) cell, but absent in the human placental choriocarcinoma cell line JAR and JEG3, implicating an unknown correlation between Dkk-1 and carcinogenesis of placental choriocarcinoma. Further, through exogenous introduction of Dkk-1, we found repressed proliferation in JAR and JEG3, induced apoptosis in JAR, and discovered significant tumor suppression effects of Dkk-1 in placental choriocarcinoma. Moreover we found that this function of Dkk-1 is achieved through c-Jun N-terminal kinase (JNK), whereas the canonical Wnt pathway may not have a great role. This discovery is not symphonic to previous functional understanding of Dkk-1, a canonical Wnt signaling antagonist. Together, our data indicate the possible correlation between Dkk-1 and human placental choriocarcinoma and suggest potential applications of Dkk-1 in treatment of human placental choriocarcinomas.
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•Effective S-scheme Ce@BiVO4 nanocomposite photocatalyst.•Efficient conversion of CO2 into significant yields of hydrocarbon fuels.•Sufficient basic sites at CeO2 surface making ...CeBV-20 nanocomposite effective for CO2 adsorption.•High separation of charge carriers identified by PL analysis in the final nanocomposite.•Highly stable and reused up to five consecutive recycling runs.
The production of hydrocarbon fuels is essential for the energy market to develop a green and sustainable environment. However, new pathways are being developed to accelerate energy production to fulfill energy demands. Here, we have developed an efficient 0D/2D CeO2/BiVO4 S-scheme heterojunction for producing methanol from CO2 in visible illuminance. The developed heterojunction photocatalyst demonstrated the excellent yield of methanol and the production of CO and CH4 in small amounts. The high yield of methanol refers to the effective charge separation and good basic sites at the heterojunction photocatalyst due to the CeO2 content, which facilitates the accommodation of CO2 molecules more efficiently at the CeO2 surface and provides a higher yield of methanol than CeO2 and BiVO4 alone. In addition, the effective charge separation between CeO2 and BiVO4 provided excellent yields of C1 solar fuels. The characteristic properties of the synthesized photocatalysts were examined using various spectroscopic and microscopic techniques. Also, the recovered photocatalyst exhibited relatively similar activity without leaching the metal content after five consecutive runs under identical experimental conditions.
Placental dysfunction underlies numerous complications of pregnancy. A major obstacle to understanding the roles of potential mediators of placental pathology has been the absence of suitable methods ...for tissue-specific gene manipulation and sensitive assays for studying gene functions in the placentas of intact animals. We describe a sensitive and noninvasive method of repetitively tracking placenta-specific gene expression throughout pregnancy using lentivirus-mediated transduction of optical reporter genes in mouse blastocysts.
Zona-free blastocysts were incubated with lentivirus expressing firefly luciferase (Fluc) and Tomato fluorescent fusion protein for trophectoderm-specific infection and transplanted into day 3 pseudopregnant recipients (GD3). Animals were examined for Fluc expression by live bioluminescence imaging (BLI) at different points during pregnancy, and the placentas were examined for tomato expression in different cell types on GD18. In another set of experiments, blastocysts with maximum photon fluxes in the range of 2.0E+4 to 6.0E+4 p/s/cm(2)/sr were transferred. Fluc expression was detectable in all surrogate dams by day 5 of pregnancy by live imaging, and the signal increased dramatically thereafter each day until GD12, reaching a peak at GD16 and maintaining that level through GD18. All of the placentas, but none of the fetuses, analyzed on GD18 by BLI showed different degrees of Fluc expression. However, only placentas of dams transferred with selected blastocysts showed uniform photon distribution with no significant variability of photon intensity among placentas of the same litter. Tomato expression in the placentas was limited to only trophoblast cell lineages.
These results, for the first time, demonstrate the feasibility of selecting lentivirally-transduced blastocysts for uniform gene expression in all placentas of the same litter and early detection and quantitative analysis of gene expression throughout pregnancy by live BLI. This method may be useful for a wide range of applications involving trophoblast-specific gene manipulations in utero.
Abstract Developing efficient and robust hydrogen evolution reaction (HER) catalysts for scalable and sustainable hydrogen production through electrochemical water splitting is strategic and ...challenging. Herein, heterogeneous Mo 8 O 26 ‐NbN x O y supported on N‐doped graphene (defined as Mo 8 O 26 ‐NbN x O y /NG) is synthesized by controllable hydrothermal reaction and nitridation process. The O‐exposed Mo 8 O 26 clusters covalently confined on NbN x O y nanodomains provide a distinctive interface configuration and appropriate electronic structure, where fully exposed multiple active sites give excellent HER performance beyond commercial Pt/C catalyst in pH‐universal electrolytes. Theoretical studies reveal that the Mo 8 O 26 ‐NbN x O y interface with electronic reconstruction affords near‐optimal hydrogen adsorption energy and enhanced initial H 2 O adsorption. Furthermore, the terminal O atoms in Mo 8 O 26 clusters cooperate with Nb atoms to promote the initial H 2 O adsorption, and subsequently reduce the H 2 O dissociation energy, accelerating the entire HER kinetics.
Three-dimensional self-organized nanoporous thin films integrated into a heterogeneous Fe2O3/Fe3C-graphene structure were fabricated using chemical vapor deposition. Few-layer graphene coated on the ...nanoporous thin film was used as a conductive passivation layer, and Fe3C was introduced to improve capacity retention and stability of the nanoporous layer. A possible interfacial lithium storage effect was anticipated to provide additional charge storage in the electrode. These nanoporous layers, when used as an anode in lithium-ion batteries, deliver greatly enhanced cyclability and rate capacity compared with pristine Fe2O3: a specific capacity of 356 μAh cm–2 μm–1 (3560 mAh cm–3 or ∼1118 mAh g–1) obtained at a discharge current density of 50 μA cm–2 (∼0.17 C) with 88% retention after 100 cycles and 165 μAh cm–2 μm–1 (1650 mAh cm–3 or ∼518 mAh g–1) obtained at a discharge current density of 1000 μA cm–2 (∼6.6 C) for 1000 cycles were achieved. Meanwhile an energy density of 294 μWh cm–2 μm–1 (2.94 Wh cm–3 or ∼924 Wh kg–1) and power density of 584 μW cm–2 μm–1 (5.84 W cm–3 or ∼1834 W kg–1) were also obtained, which may make these thin film anodes promising as a power supply for micro- or even nanosized portable electronic devices.
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