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Constructing heterostructured electrocatalysts has proven effective in enhancing intrinsic catalytic activity. Herein, under guidance of theoretical calculations, hierarchical porous quasi-hexagonal Co2P nanosheets/Co heterostructures supported on carbon cloth (Co2P/Co/CC) with a high surface area were rationally designed and elaborately constructed through electroless Co plating, electrochemical oxidation, and phosphidation process, which showed significant electrocatalytic performance toward water electrolysis. Specifically, theoretical calculations revealed that the Co2P/Co heterostructure adjusted the electronic structure of Co2P and Co, reducing the energy barrier for target reactions and thereby boosting electrocatalytic activities for the hydrogen evolution reaction (HER). Notably, the typical Co2P/Co/CC catalyst demonstrated impressive HER performance, with low overpotentials of only 52 and 48 mV to achieve a current density of 10 mA/cm2 in 0.5 M H2SO4 and 1.0 M KOH solutions, respectively. The remarkable electrocatalytic performance of the catalyst can be attributed to the improved intrinsic activity resulting from the Co2P/Co heterostructures and the highly exposed active sites provided by the hierarchical porous structures. Furthermore, the Co2P/Co/CC catalyst exhibited excellent oxygen evolution reaction (OER) performance in alkaline electrolyte, requiring a low overpotential of only 306 mV to achieve a current density of 100 mA/cm2. Additionally, a two-electrode electrolyzer assembled with the Co2P/Co/CC electrodes achieved a current density of 10 mA/cm2 at a low cell voltage of 1.54 V and demonstrated excellent long-term stability. This work presents a novel and feasible strategy for constructing hierarchical heterostructured electrocatalysts that enable efficient water electrolysis. By combining rational design and theoretical guidance, our approach offers promising prospects for advancing the field of electrocatalysis and facilitating sustainable energy conversion.
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Rare earth element neodymium (Nd) is widely used in industry and agriculture, which may result in the pollution of aquatic environment. In this study, we exposed zebrafish with 10, 50, and 100 µg/L Nd for four weeks. The results showed that Nd could be accumulated in fish gill and Nd accumulation affected the equilibrium of nutrient elements. Nd decreased the antioxidant enzymes' activity and gene expression level, but enhanced the generation of reactive oxygen species (ROS). Moreover, various concentration of Nd treatments inhibited Nrf2 signaling in gill. To examine the critical role of GSK-3ß/Nrf2 signaling on ROS generation under Nd stress, we further interfered gsk-3ß gene in zebrafish under 100 µg/L Nd exposure. The result showed that gsk-3ß gene interference induced Nrf2 signaling as well as the expression and activity of antioxidant enzymes in fish gill. In all, Nd could be accumulated in fish gill, and the signaling of GSK-3ß/Nrf2 was involved in regulating ROS generation under Nd treatments.
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Contaminantes Químicos del Agua , Pez Cebra , Animales , Antioxidantes/metabolismo , Branquias/metabolismo , Glucógeno Sintasa Quinasa 3 beta/genética , Glucógeno Sintasa Quinasa 3 beta/metabolismo , Neodimio/metabolismo , Neodimio/farmacología , Neodimio/toxicidad , Factor 2 Relacionado con NF-E2/genética , Factor 2 Relacionado con NF-E2/metabolismo , Estrés Oxidativo , Especies Reactivas de Oxígeno/metabolismo , Contaminantes Químicos del Agua/farmacología , Contaminantes Químicos del Agua/toxicidad , Pez Cebra/metabolismoRESUMEN
With the energy crisis and environmental pollution becoming more and more serious, it is urgent to develop renewable and clean energy. Hydrogen production from electrolyzed water is of great significance to solve the energy crisis and environmental problems in the future. Recently, layered double hydroxides (LDHs) materials have been widely studied in the electrocatalysis field, due to their unique layered structure, tunable metal species and highly dispersed active sites. Moreover, the LDHs supporting noble metal catalysts obtained through the topotactic transformation of LDHs precursors significantly reduce the energy barrier of electrolyzing water, showing remarkable catalytic activity, good conductivity and excellent durability. In this review, we give an overview of recent advances on LDHs supporting noble metal catalysts, from a brief introduction, to their preparation and modification methods, to an overview of their application in the electrocatalysis field, as well as the challenges and outlooks in this promising field on the basis of current development.
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Hydrogen-induced disproportionation (HID) during the cycles of absorption and desorption leads to a serious decline in the storage capacity of the ZrCo alloy, which has been recognized as the biggest obstacle to its application. Therefore, the prerequisite of a ZrCo application is to solve its anti-disproportionation problem in the field of rapid hydrogen isotope storage. Beyond surface modification and nanoball milling, this work systematically reviews the method of element substitution, which can obviously improve the anti-disproportionation. From a micro angle, as hydrogen atoms that occupy the 8e site in the ZrCoH3 lattice are instable and are considered to be the driving force of disproportionation, researchers believe that element substitution by changing the occupation of hydrogen atoms at the 8e site can improve the anti-disproportionation of the alloy. At present, Ti/Nb substitutions for the Zr terminal among substitute elements have an excellent anti-disproportionation performance. In this work, up-to-date research studies on anti-disproportionation and its disproportionation mechanism of the ZrCo alloy are introduced by combining experiments and simulations. Moreover, the optimization of the alloy based on the occupation mechanism of 8e sites is expected to improve the anti-disproportionation of the ZrCo alloy.
RESUMEN
Oxygen vacancies or defects play a significant role in improving the intrinsic activities of bimetallic hydroxides towards the oxygen evolution reaction (OER); however, their rational design and preparation remain a great challenge. In this study, oxygen vacancy-rich amorphous porous nickel iron hydroxide nanolayers supported on carbon paper (NiFe(OH)x/CP) are rationally prepared through a facile approach involving the sequential electrochemical deposition of a Prussian blue (PB) nanocrystal layer and Ni(OH)x layer on carbon paper followed by an alkaline etching process, where PB nanocrystals act as an Fe source and template for the formation of an amorphous porous NiFe(OH)x layer. NiFe(OH)x/CP with an ultralow loading of 0.8 mg cm-2 exhibits outstanding OER activities, showing a low overpotential of 303 mV at 100 mA cm-2 and a small Tafel slope of 33.8 mV dec-1 in an alkaline electrolyte, which are superior to the state-of-the-art IrO2 catalysts, and among the best results compared to the reported bimetallic compounds. Moreover, NiFe(OH)x/CP exhibits excellent long-term stability with negligible degradation after water splitting for 50 h. Its superior electrocatalytic OER performance benefits from the massive oxygen vacancies derived from the amorphous and distorted structures, the synergistic effect between Ni and Fe species with an optimized Ni/Fe ratio, and the efficient electron and mass transfer of carbon paper. This work paves a new avenue for the rational design and preparation of amorphous porous structures with abundant oxygen vacancies to improve the intrinsic activities for energy storage and conversion applications.
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Humidity sensors are a common, but important type of sensors in our daily life and industrial processing. Graphene and graphene-based materials have shown great potential for detecting humidity due to their ultrahigh specific surface areas, extremely high electron mobility at room temperature, and low electrical noise due to the quality of its crystal lattice and its very high electrical conductivity. However, there are still no specific reviews on the progresses of graphene-based humidity sensors. This review focuses on the recent advances in graphene-based humidity sensors, starting from an introduction on the preparation and properties of graphene materials and the sensing mechanisms of seven types of commonly studied graphene-based humidity sensors, and mainly summarizes the recent advances in the preparation and performance of humidity sensors based on pristine graphene, graphene oxide, reduced graphene oxide, graphene quantum dots, and a wide variety of graphene based composite materials, including chemical modification, polymer, metal, metal oxide, and other 2D materials. The remaining challenges along with future trends in high-performance graphene-based humidity sensors are also discussed.
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Tetrakis (4-carboxyphenyl) porphyrin (TCPP) and polyelectrolyte poly(N-methyl-2-vinylpyridinium iodide)-b-poly(ethylene oxide) (PMVP41-b-PEO205) can self-aggregate into polyion complex (PIC) micelles in alkaline aqueous solution. UV-vis spectroscopy, fluorescence spectroscopy, transmission electron microscope, and dynamic light scattering were carried out to study PIC micelles. Density functional theory (DFT) calculation method was applied to study the interaction of TCPP and PMVP41-b-PEO205. We found that the H-aggregates and J-dimers of anionic TCPP transformed in PIC micelles. H-aggregates of TCPP formed at the charge ratio of TCPP/PMVP41-b-PEO205 1:2 and J-dimer species at the charge ratio above 1:4, respectively. It is worth noting that the transformation from H-aggregates to J-dimer species of TCPP occurred just by adjusting the ratio of polymer and TCPP rather than by changing other factors such as pH, temperature, and ions.
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Polyion complexes have been known about for decades, with their applications mainly restricted to drug and gene delivery. In this study, we show that by the introduction of fluorescent charged molecules into a polyion complex, it can be used as a specific detection system for surfactants. The fluorescence of 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt (HPTS) is quenched in the ionic complex, while it can be recovered with the addition of the surfactant sodium dodecylbenzenesulfonate (SDBS), due to the stronger interaction between SDBS and the polyelectrolyte. This leads to a drastic color change of the solution, and a recovery of the strong emission of HPTS. Specifically, the fluorescence is linearly proportional to the concentration of SDBS, thus it can be used for the qualitative detection of SDBS. Furthermore, the detection limit for SDBS can be up to the order of 10-10 M. We believe that competitive dissociation of the ionic complex can be used as a general approach for the construction of new functional materials.
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About 40-60% of ovarian cancer (OVCA) cases express ERα, but only a small proportion of patients respond clinically to anti-estrogen treatment with estrogen receptor (ER) antagonist tamoxifen (TAM). The mechanism of TAM resistance in the course of OVCA progression remains unclear. However, IL6 plays a critical role in the development and progression of OVCA. Our recent results indicated that IL6 secreted by OVCA cells may promote the resistance of these cells to TAM via ER isoforms and steroid hormone receptor coactivator-1. Here we demonstrate that both exogenous (a relatively short period of treatment with recombinant IL6) and endogenous IL6 (generated as a result of transfection with a plasmid encoding sense IL6) increases expression of pERα-Ser118 and pERα-Ser167 in non-IL6-expressing A2780 cells, while deleting endogenous IL6 expression in IL6-overexpressing CAOV-3 cells (by transfection with a plasmid encoding antisense IL6) reduces expression of pERα-Ser118 and pERα-Ser167, indicating that IL6-induced TAM resistance may also be associated with increased expression of pERα-Ser118 and pERα-Ser167 in OVCA cells. Results of further investigation indicate that IL6 phosphorylates ERα at Ser118 and Ser167 by triggering activation of MEK/ERK and phosphotidylinositol 3 kinase/Akt signaling, respectively, to activate the ER pathway and thereby induce OVCA cells resistance to TAM. These results indicate that IL6 secreted by OVCA cells may also contribute to the refractoriness of these cells to TAM via the crosstalk between ER and IL6-mediated intracellular signal transduction cascades. Overexpression of IL6 not only plays an important role in OVCA progression but also promotes TAM resistance. Our results indicate that TAM-IL6-targeted adjunctive therapy may lead to a more effective intervention than TAM alone.
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Antineoplásicos Hormonales/farmacología , Receptor alfa de Estrógeno/metabolismo , Interleucina-6/fisiología , Tamoxifeno/farmacología , Línea Celular Tumoral , Resistencia a Antineoplásicos , Activación Enzimática , Femenino , Humanos , Sistema de Señalización de MAP Quinasas , Neoplasias Ováricas , Fosfatidilinositol 3-Quinasas/metabolismo , Fosforilación , Procesamiento Proteico-Postraduccional , Proteínas Proto-Oncogénicas c-akt/metabolismoRESUMEN
We reported two cases of liver metastasis with portal vein tumor thrombus that developed after liver transplantation for hepatocellular carcinoma (HCC). Both the patients were women aged 43 and 55 years, who had liver metastasis and portal vein tumor thrombus formation after liver transplantations for HCC. For the treatment of portal vein tumor thrombus, (125)I seeds were implanted into the hepatic tissue under the guidance of preoperative computed tomography (CT) images with a total radiation dose of 130 Gy. Enhanced spiral CT scan was performed for evaluation of the liver at 12 and 16 wk after treatment. Thereafter, upper abdominal CT examination was performed every 2-3 mo. No severe complications associated with the (125)I seeds were seen in these two patients. The upper abdominal CT images (obtained after 3 and 4 mo of treatment) showed that the thrombosis reactions were complete reaction and restoration of the patency of the partially obstructed portal vein with partial obstruction. In the case with complete obstruction of the portal vein, the thrombosis was resolved completely, but blood flow could not be restored. After this treatment, one of the patients is still alive, while the other died within 6 mo after the treatment due to lung metastasis complicated with lung infection, leading to respiratory failure.
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Braquiterapia/métodos , Carcinoma Hepatocelular , Radioisótopos de Yodo/uso terapéutico , Neoplasias Hepáticas , Vena Porta , Trombosis de la Vena/radioterapia , Adulto , Carcinoma Hepatocelular/diagnóstico por imagen , Carcinoma Hepatocelular/patología , Carcinoma Hepatocelular/secundario , Carcinoma Hepatocelular/terapia , Femenino , Humanos , Neoplasias Hepáticas/diagnóstico por imagen , Neoplasias Hepáticas/patología , Neoplasias Hepáticas/terapia , Trasplante de Hígado/efectos adversos , Persona de Mediana Edad , Tomografía Computarizada por Rayos X/métodosRESUMEN
OBJECTIVE: To determine the contents of NOS and endogenous CO in the penile corpus cavernosum of Wistar rat models of hyperthyroid and hypothyroid, to detect the effects of thyroid hormone and endogenous CO on rat penile erection, and to further investigate the influence of thyroid hormone on human penile erection. METHODS: Fifty 3-month-old male Wistar rats were randomly and equally divided into 5 groups: a hyperthyroid, a hyperthyroid treatment, a hypothyroid, a hypothyroid treatment and a control group. The contents of NOS and CO were detected by ultraviolet spectrophotometry. RESULTS: Compared with the controls, the content of NOS was significantly decreased in both the hyperthyroid and the hypothyroid groups (P < 0.01), even lower in the latter than in the former (P < 0.01), and so was the content of CO (P < 0.01), lower in the former than in the latter (P < 0.01). After treatment, the levels of NOS and CO were both elevated in either the hyperthyroid or the hypothyroid group, with no significant difference from that of the controls (P > 0.05). CONCLUSION: The contents of NOS and CO in the penile corpus cavernosum decrease with the imbalance of thyroid hormones, but return to normal once the imbalance is corrected. Under the same conditions, hypothyroid inflicts more damage on penile erection than hyperthyroid.
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Pene/metabolismo , Hormonas Tiroideas/farmacología , Animales , Monóxido de Carbono/metabolismo , Modelos Animales de Enfermedad , Hipertiroidismo/tratamiento farmacológico , Hipotiroidismo/tratamiento farmacológico , Masculino , Óxido Nítrico Sintasa/metabolismo , Pene/efectos de los fármacos , Ratas , Ratas Wistar , Hormonas Tiroideas/uso terapéuticoRESUMEN
OBJECTIVE: To detect the levels of nitric oxide synthetase (NOS) and carbon monoxide (CO) in the penile corpus cavernous of adult male Wistar rats with high homocysteine (Hhcy) and to explore the relationship of NOS and CO levels with erectile dysfunction. METHODS: Twenty Wistar rats were equally and randomly divided into a control and an Hhcy group and fed on normal diet and normal diet with 3.0% methionine respectively. Four weeks later, the levels of NOS and CO in the penile corpus cavernous were detected by ultraviolet spectrophotometry and that of serum homocysteine by the cycle enzyme method. RESULTS: Compared with the control group, the levels of NOS and CO in the penile corpus cavernous were significantly lower in the Hhcy group, (6.45 +/- 1.12) nmol/(g x min) vs (10.77 +/- 0.60) nmol/(g x min) and (10.60 +/- 0.92) micromol/L vs (13.36 +/- 0.44) micromol/L, while that of homocysteine was significantly higher, (22.32 +/- 1.65) micromol/L) vs (4.90 +/- 1.73) micromol/L. CONCLUSION: Four-week diet with methionine can cause Hhcy and significantly decreased levels of NOS and CO in the penile corpus cavernous in Wistar rats. Hhcy is an independent risk factor of erectile dysfunction.
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Monóxido de Carbono/metabolismo , Hiperhomocisteinemia/fisiopatología , Óxido Nítrico Sintasa/metabolismo , Pene/metabolismo , Animales , Homocisteína/sangre , Hiperhomocisteinemia/sangre , Masculino , Ratas , Ratas Wistar , Espectrofotometría UltravioletaRESUMEN
By the method of individual culture and with 3.0 x 10(6) cells ml(-1) of Scenedesmus obliquus as the food, a comparative study was made on the characteristics in life history of Brachionus forcatus and B. caudatus at 18 degrees C, 23 degrees C, 28 degrees C and 33 degrees C. The results showed that at 18 degrees C and 23 degrees C, both the reproductive stage and the mean lifespan of B. caudatus were longer than those of B. forcatus, and the number of eggs produced by B. caudatus in its whole life was larger than that by B. forcatus. At 28 degrees C , there were no significant differences between B. forcatus and B. caudatus in the durations of their main development stages, mean lifespan, and the number of eggs produced. At 33 degrees C, the reproductive and post-reproductive stages and the mean lifespan of B. forcatus were longer than those of B. caudatus, and the number of eggs produced by B. forcatus in its whole life was larger than that by B. caudatus. At 18 degrees C, the life expectancy at hatching, net reproductive rate, and intrinsic rate of population increase were all larger for B. caudatus than for B. forcatus; but at 23 degrees C and 28 degrees C, only the life expectancy at hatching was larger for B. caudatus than for B. forcatus. When the temperature reached 33 degrees C, the generation time, life expectancy at hatching, net reproductive rate, and intrinsic rate of population increase were all larger for B. forcatus than for B. caudatus. There also existed differences between B. forcatus and B. caudatus in the responses of the durations of their main development stages, mean lifespan, number of eggs produced in whole life, generation time, life expectancy at hatching, net reproductive rate, and intrinsic rate of population increase to increasing temperature. B. caudatus was more adaptable to lower temperature, while B. forcatus was in adverse.