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1.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 36(4): 297-303, 2020 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-32519666

RESUMO

Objective To investigate the effect of Wenweishu Capsule on the expression of nuclear factor kappa B (NF-κB)-related proteins in chronic gastritis model rats. Methods Wistar rat models of chronic gastritis were constructed by alternant administrations of sodium deoxycholate, ammonia, alcohol solution and the hunger disorder method. The rats were randomly divided into control group, model group, vatacoenayme group, high-, middle- and low-dose Wenweishu Capsule groups. The control group and model group were treated with normal saline (2 mL/d). The other groups were separately treated with 0.3 g/kg vatacoenayme and 0.76, 0.38, 0.19 g/kg Wenweishu Capsule for 4 weeks. Naked eye observation and HE staining were used to evaluate the pathological changes of gastric tissue. ELISA was performed to measure the levels of tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6) in the serum. Immunofluorescence staining was employed to observe the expression of NF-κBp65, inhibitor of NF-κBα (IκBα) in the gastric tissue. Simple Western was utilized to detect the protein levels of NF-κBp65, IκBα and COX2 in the gastric tissue. Results Compared with the control group, the model group was found with thinner gastric mucosa, disappeared or shallower folds, obviously infiltrated mucosa inflammatory cells, disordered glands, and significantly increased levels of serum inflammatory cytokines and NF-κBp65, IκBα and COX2 proteins in the gastric tissue. Compared with the model group, the vatacoenayme group, high- and middle-dose Wenweishu Capsule groups showed the alleviated gastric cavity signs, improved histopathological changes, reduced levels of TNF-α and IL-6 in the serum, and decreased expression of NF-κBp65, IκBα and COX2 proteins in the gastric tissue. Conclusion Wenweishu Capsule can reduce the levels of serum inflammatory factors by inhibiting NF-κB pathway in the gastric tissue, so as to alleviate the injury of gastric mucosa in rats with chronic gastritis.

2.
Adv Mater ; : e2001300, 2020 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-32490580

RESUMO

Topological defects, with an asymmetric local electronic redistribution, are expected to locally tune the intrinsic catalytic activity of carbon materials. However, it is still challenging to deliberately create high-density homogeneous topological defects in carbon networks due to the high formation energy. Toward this end, an efficient NH3 thermal-treatment strategy is presented for thoroughly removing pyrrolic-N and pyridinic-N dopants from N-enriched porous carbon particles, to create high-density topological defects. The resultant topological defects are systematically investigated by near-edge X-ray absorption fine structure measurements and local density of states analysis, and the defect formation mechanism is revealed by reactive molecular dynamics simulations. Notably, the as-prepared porous carbon materials possess an enhanced electrocatalytic CO2 reduction performance, yielding a current density of 2.84 mA cm-2 with Faradaic efficiency of 95.2% for CO generation. Such a result is among the best performances reported for metal-free CO2 reduction electrocatalysts. Density functional theory calculations suggest that the edge pentagonal sites are the dominating active centers with the lowest free energy (ΔG) for CO2 reduction. This work not only presents deep insights for the defect engineering of carbon-based materials but also improves the understanding of electrocatalytic CO2 reduction on carbon defects.

3.
Chemosphere ; 252: 126622, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32443279

RESUMO

This study aims at exploring the mechanism of fast-stimulating bioremediation of macro crude oil using matching Fenton pre-oxidation. The 80-day biodegradation experiment for soil S1 and S2, containing macro crude oil: C19-C29 and C17-C29 respectively, was conducted after Fenton pre-oxidation with three concentrations of H2O2 (225 mM, 450 mM, and 900 mM). Experimental results indicated that the bioremediation efficiency of macro crude oil was up to 57.1% (8853 mg/kg, S1) and 64.4% (11,719 mg/kg, S2) for 80-day fast-stimulating bioremediation using matching Fenton pre-oxidation (450 mM H2O2), which was 1.8-2.6 times that (S1: 22.2-37.1%; S2: 36.1-39.6%) for slow-stimulating bioremediation using un-matching Fenton pre-oxidation. Furthermore, the high-throughput analysis revealed that genera Sedimentibacter, Caenispirillum, and Brevundimonas became the dominant bacteria after matching Fenton pre-oxidation. Meanwhile, the highest logarithmic growth rate of indigenous hydrocarbon degraders (IHD) was obtained (S1: 64% and S2: 60%) for fast-stimulating bioremediation. And the consumption of NH4+-N was up to 90% and 94% in S1 and S2 within 60 days for fast-stimulating bioremediation, approximately 1.4 and 2.2 times that (S1: 65% and 62%; S2: 47% and 41%) for slow-stimulating remediation. The results showed that the macro crude oil became the main carbon source for IHD for the fast-stimulating bioremediation, resulting in the rapid growth of IHD. Thus, this study provides a fast and efficient remediation technology for bioremediation of macro crude oil-contaminated soils.

4.
Biosci Rep ; 40(5)2020 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-32342981

RESUMO

We aim to determine whether nebivolol has a better effect on endothelial dysfunction compared with other ß-blockers or other classes of antihypertensive drugs. Searches of the PubMed, Embase etc. were performed to analyze all the randomized controlled trials using nebivolol to treat essential hypertension. The primary end points included a measurement of peripheral endothelial function by brachial flow mediated vasodilatation (FMD) or forearm blood flow (FBF). A random-effect model was used to perform the meta-analysis when the studies showed significant heterogeneity, otherwise a descriptive analysis was conducted. Ten studies (689 patients) were included in qualitative analysis, four of which were included in quantitative synthesis. Meta-analysis showed that the changed FMD value before and after treatment with nebivolol was not statistically different from those treated with other ß-blockers [mean difference = 1.12, 95% confidence interval (CI): -0.56, 2.81, P=0.19]. Descriptive analysis indicated that nebivolol did not have a better endothelium-protective effect than other classes of antihypertensive drugs including olmesartan and perindopril. Nebivolol is not a unique endothelial function-protective agent distinguished from other ß-blockers or other classes of antihypertensive drugs. Reversal of endothelial dysfunction is a key point in the prevention and therapy of essential hypertension.

5.
Hypertens Res ; 43(6): 511-517, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32042143

RESUMO

MicroRNAs are key molecules involved in the regulation of endothelial function. They are important risk factors and biomarkers for the development of hypertension related to endothelial dysfunction. However, the gene expression patterns associated with hypertension development related to endothelial dysfunction have not been fully elucidated. We conducted a case-control study of 65 patients with essential hypertension (EH) and 61 controls without EH. Plasma levels of miR-122 and its target protein high-affinity cationic amino acid transporter 1 (CAT-1) were measured by qRT-PCR and ELISA, respectively. miR-122 expression in plasma of patients with EH was significantly higher than that of the control group (p = 0.001), while CAT-1 expression in patients with EH was significantly lower than that in the control group (p = 0.018). miR-122 expression in plasma of young patients with EH was significantly higher than that in young people without EH (p = 0.0004), and CAT-1 expression in plasma of young patients with EH was also significantly lower than that of the control group (p = 0.002). CAT-1 expression in the plasma of young participants was significantly higher than that of individuals aged ≥40 years (p = 0.003), whereas miR-122 expression was significantly lower (p = 0.001). We showed that among patients with EH, the high expression of miR-122 contributed to endothelial dysfunction by suppressing the expression of the CAT-1 protein, which led to a decrease in CAT-1 expression in plasma. Therefore, high expression of miR-122 appears to be a risk factor for endothelial dysfunction in EH, especially in younger patients.

6.
Chem Commun (Camb) ; 56(11): 1749-1752, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-31942911

RESUMO

Magnesium doped ultra-fine RuO2 nanoparticles are prepared by a one-step annealing of Ru-exchanged Mg-MOF-74. Mg-RuO2 exhibits excellent oxygen evolution reaction performance with a low overpotential of 228 mV at 10 mA cm-2. The excellent performance is attributed to the altered electronic structure and the optimized surface atomic arrangement.

7.
Nanoscale ; 12(2): 538-547, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31850430

RESUMO

The development of highly efficient metal or metal compound electrocatalysts under mild conditions has always been a challenging task for N2 reduction. Herein, we show that pristine two-dimensional (2D) MXenes are promising N2 electroreduction catalysts due in part to the availability of multiple active sites per unit area. We systematically explore a series of 3d, 4d and 5d-transition metal M2C (M = Sc, Ti, V, Cr, Mn, Fe, Zr, Nb, Mo, Ta and Hf) MXenes and compute their limiting potentials for the N2 reduction reaction (NRR). We find that 4d4-Mo2C gives rise to the lowest free-energy barrier (ΔG) of 0.46 eV, among the synthesized M2C MXenes as of today. More importantly, we find that two hypothetical MXenes, 3d5-Mn2C and 3d6-Fe2C, possess even lower ΔG of 0.28 and 0.23 eV, respectively, compared to the state-of-the-art 4d4-Mo2C, thereby likely being more efficient NRR catalysts. The N2 capture strength, a key parameter of the potential-limiting step, is found to be closely related to the d-electron arrangement on the occupied and empty spin-split d-orbitals. Hence, the excellent NRR performance of Mn2C and Fe2C can be attributed to the desirable half-filled 3d5 or 3d6 electron arrangements. The adsorption of N2 on Mn2C results in the donation of 1σ electrons to the empty spin-down 3d orbitals of Mn. The donated electrons weaken the N2 adsorption strength and lower the energy barrier of the potential-limiting step of hydrogenation. The insights obtained from this comprehensive study offer guidance to design new and efficient electrocatalysts for N2 fixation.

8.
Huan Jing Ke Xue ; 40(11): 5124-5132, 2019 Nov 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854582

RESUMO

To obtain a mild Fenton pre-oxidation method, which could promote the efficient degradation of total petroleum hydrocarbons (TPH) in subsequent bioremediation, the differences in the characteristics of the hydroxyl radical (·OH), nutrient consumption, activity of indigenous bacteria (CO2), and TPH removal were investigated during subsequent bioremediation after different Fenton pre-oxidation treatments. The results showed that high biodegradation of TPH was observed after mild Fenton pre-oxidation (·OH existence time:73 h; H2O2 concentration:225 mmol·L-1), because of the high activity of residual bacteria. Moreover, the same TPH removal with the addition of bacteria could be achieved without adding bacteria (the TPH removal rate 38%) because the activity of the residual bacteria was strong after mild Fenton pre-oxidation. Under the condition of no additional bacteria source, mild Fenton pre-oxidation TPH removal (approximately 38%) was higher than that after ordinary Fenton pre-oxidation (15.32%-33.15%). Further analysis of the removal efficiency of each chain of hydrocarbons revealed that the mild pre-oxidation group could reduce the inhibition of the chain hydrocarbon components (C17-C21) in the subsequent bioremediation stage. Comparing the activity of the indigenous bacteria in each group, revealed that mild pre-oxidation could appropriately stimulate the growth and increase the activity of indigenous microorganisms, all of which are beneficial to the removal of TPH.


Assuntos
Petróleo , Poluentes do Solo , Biodegradação Ambiental , Hidrocarbonetos , Peróxido de Hidrogênio , Solo , Microbiologia do Solo
9.
iScience ; 23(1): 100756, 2019 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-31887659

RESUMO

Active and highly stable electrocatalysts for oxygen evolution reaction (OER) in acidic media are currently in high demand as a cleaner alternative to the combustion of fossil fuels. Herein, we report a Co-doped nanorod-like RuO2 electrocatalyst with an abundance of oxygen vacancies achieved through the facile, one-step annealing of a Ru-exchanged ZIF-67 derivative. The compound exhibits ultra-high OER performance in acidic media, with a low overpotential of 169 mV at 10 mA cm-2 while maintaining excellent activity, even when exposed to a 50-h galvanostatic stability test at a constant current of 10 mA cm-2. The dramatic enhancement in OER performance is mainly attributed to the abundance of oxygen vacancies and modulated electronic structure of the Co-doped RuO2 that rely on a vacancy-related lattice oxygen oxidation mechanism (LOM) rather than adsorbate evolution reaction mechanism (AEM), as revealed and supported by experimental characterizations as well as density functional theory (DFT) calculations.

10.
Medicine (Baltimore) ; 98(47): e17901, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31764787

RESUMO

BACKGROUND: Salpingectomy is routinely performed in ectopic pregnancy (EP). However, the effect of the surgery on the ovarian reserve and ovarian response in EP patients is still uncertain and has not been systematically evaluated. Therefore, we conducted this meta-analysis to provide a comparison of the ovarian reserve and ovarian response between the pre-salpingectomy and post-salpingectomy in EP patients. METHODS: Pubmed, Embase, and Cochrane Library were searched for all relevant articles published up to December 2018. We retrieved the basic information and data of the included studies. The data was analyzed by Review Manager 5.3 software (Cochrane Collaboration, Oxford, UK). RESULTS: A total of 243 articles were extracted from the databases, and 7 studies were included in the meta-analysis. The ovarian reserve including anti-Mullerian hormone (inverse variance [IV] -0.7 [95% confidence interval [CI] -0.63, 0.49]), antral follicle count (IV 1.7 [95% CI -2.02, 5.42]) and basal follicle stimulating hormone (IV 0.02 [95% CI -0.63, 0.68]) was comparable between the pre-salpingectomy group and the post-salpingectomy group. The amount of gonadotropin was significantly higher in the post-salpingectomy group when compared with that in the pre-salpingectomy group (IV -212.65 [95% CI -383.59, -41.71]). There was no significant difference in the left parameters of the ovarian response including the duration of gonadotropin stimulation (IV -0.32 [95% CI -0.76, 0.12]), the estrogen level on the human chorionic gonadotropin triggering day (IV -4.12 [95% CI -236.27, -228.04]) and the number of retrieved oocytes (IV 0.35 [95% CI -0.76, 1.46]) between 2 groups. CONCLUSIONS: The current results suggest that salpingectomy has no negative effect on the ovarian reserve and ovarian response.


Assuntos
Reserva Ovariana , Ovário/fisiopatologia , Gravidez Ectópica/fisiopatologia , Gravidez Ectópica/cirurgia , Salpingectomia , Feminino , Humanos , Gravidez
11.
IEEE Int Conf Rehabil Robot ; 2019: 709-714, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31374714

RESUMO

In order to provide an effective system for rehabilitation of walking, a new rotational orthosis for walking with arm swing, called ROWAS II, was developed. This study focused on development and implementation of admittance control of the ankle mechanism in the ROWAS II system for promoting active training. Firstly, the mechanical structure of the ankle mechanism is briefly introduced. Then the algorithms of the closed-loop position control and the admittance control for the ankle mechanism are described in detail. Four able-bodied participants were recruited to use the ankle mechanism running in passive and active modes. The experimental results showed that the ankle mechanism well tracked the target trajectory in passive mode. In active mode, the participants interacted with the ankle mechanism, and adjusted their ankle movement based on their active force. The ankle mechanism has the technical potential to meet the requirements of passive and active training in the ankle movement for patients in different post-stroke stages.


Assuntos
Tornozelo/fisiologia , Marcha/fisiologia , Aparelhos Ortopédicos , Rotação , Caminhada/fisiologia , Adulto , Algoritmos , Fenômenos Biomecânicos , Feminino , Humanos , Masculino , Adulto Jovem
12.
Waste Manag ; 85: 361-373, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30803591

RESUMO

The objective of this study is to explore how to stimulate soil indigenous bacteria for the degradation of long-chain crude oil by adding fermented food waste supernatant (FS). Four concentrations of FS (0 mL, 0.1 mL, 1 mL, and 3 mL) were added to two oil-contaminated soils S1 and S2 for 30 days of bioremediation experiments. The results showed that the biodegradation of long-chain alkanes (C29 - C24) could reach up to 1756 mg/kg (49.3%, S1) and 3937 mg/kg (43.9%, S2), which were 3.1 and 3.2 times that of the non-nutrient system. In addition, the logarithmic growth rate of the indigenous hydrocarbon degraders (IHD) reached 41.5%. The long-chain crude oil can be rapidly degraded by indigenous bacteria with FS added in a short time. The glucose and acetic acid accelerated the consumption of ammonia nitrogen (NH4+-N) in the prophase of bioremediation and the molar ratio of consumed carbon (contained in glucose and acetic acid) to consumed NH4+-N (C/N) was high by adding FS. Thus, the IHD can multiply rapidly. The analysis of microbial diversity revealed that the IHD (genera Acinetobacter and Aquabacterium) became the dominant bacteria. Long-chain alkanes became the main carbon sources for IHD after 14 days in soil S1 and 16 days in soil S2. Thus, the rapid biodegradation of long-chain crude oil was achieved. The genus Aquabacterium which was uncultivable on crude oil medium became the dominant bacteria. This study provides an environment-friendly and sustainable remediation technology for bioremediation of oil-contaminated soils.


Assuntos
Alimentos e Bebidas Fermentados , Petróleo , Poluentes do Solo , Bactérias , Biodegradação Ambiental , Hidrocarbonetos , Solo , Microbiologia do Solo
13.
Sci Total Environ ; 651(Pt 2): 2546-2557, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30340190

RESUMO

The concept of Ecosystem Service (ES) has provided an underpinning framework for ecological restoration research and applications. Ecological restoration is a corrective intervention that aims to reverse land degradation and to contribute to the 2030 Global Sustainable Development goal of Land Degradation Neutrality. It is critical to investigate the long-term effects of ecological restoration and land use change on ESs and ES interactions (synergies or trade-offs) to better understand the mechanisms supporting this goal. This paper describes an analysis of land use and ESs using historical data for a typical watershed in Chinese Loess Plateau, which has experienced series of restoration activities since the 1950s. Six important ESs (food provisioning, soil retention, hydrological regulation, carbon sequestration, water purification and habitat provisioning for biodiversity) were quantified at eight intervals between 1958 and 2015. The interactions between ESs were evaluated by correlation analysis. The results show that soil retention, carbon sequestration, water purification and habitat provisioning for biodiversity increased significantly across the different land use types over several decades but not hydrological regulation. The relationship between ESs was found to be variable over different time periods and a transition point between 1990 and 1995 was identified. Grassland was found to maintain greater water yield than woodland with high values of other ESs. The results suggest that trade-offs between ESs can be mitigated by adjusting the proportion of some important land use types (such as woodland and grassland).

14.
Microcirculation ; 26(1): e12515, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30431204

RESUMO

OBJECTIVE: To investigate the effects of TNF-α-induced exosomes release on the biological behavior, metabolism, and bioenergetics of HUVECs. METHODS: Exosomes were isolated from conditioned media of HUVECs by ultracentrifugation after treatment with or without TNF-α. HUVECs were treated with or without TNF-α, or different concentrations of exosomes isolated from conditioned media with or without TNF-α induction (TExo and CExo , respectively). RESULTS: The results showed that TNF-α significantly inhibited migration, tube formation, and increased apoptosis rate of HUVECs compared with controls. Furthermore, TNF-α-induced exosomes (TExo ) rather than CExo , indicated similar effects to inhibit migration, tube formation and promote endothelial apoptosis. Although TNF-α treatment did not show a statistical difference, TExo significantly inhibited extracellular OCR compared with controls. TExo could significantly inhibited intracellular OCR in a hypoxia condition. TNF-α significantly increased L-ECA compared with control cells, and TExo showed similar stimulative effect on L-ECA. CONCLUSIONS: TNF-α-induced exosomes could significantly (a) change migration, tube formation, and apoptosis; (b) inhibit endothelial extracellular OCR and intracellular OCR (hypoxia); (c) increase glycolysis rate of the endothelial cells. These data provide new evidence for exploring endothelial behavior regulation using exosomes and their effects on endothelial metabolism and bioenergetics.


Assuntos
Exossomos/fisiologia , Células Endoteliais da Veia Umbilical Humana/metabolismo , Fator de Necrose Tumoral alfa/farmacologia , Apoptose , Movimento Celular , Células Cultivadas , Metabolismo Energético , Exossomos/efeitos dos fármacos , Glicólise , Células Endoteliais da Veia Umbilical Humana/citologia , Células Endoteliais da Veia Umbilical Humana/fisiologia , Células Endoteliais da Veia Umbilical Humana/ultraestrutura , Humanos , Hipóxia , Ácido Láctico/metabolismo , Consumo de Oxigênio
15.
Med Biol Eng Comput ; 57(4): 877-886, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30465322

RESUMO

Accurate models that describe temporal-spatial parameters are desirable in gait estimation and rehabilitation. This study aimed to explore simple but relatively accurate models to describe stride length (SL), speed (SP) and walk ratio (WR) at various cadences. Twenty-four able-bodied participants (16 in a test group and 8 in a validation group) walked at seven cadence ratios (CRs). The individual and group mean SL, SP and WR were studied. Suitable temporal-spatial model structures were proposed and used to approximate the individual SL, SP and WR at various CRs. After the temporal-spatial model structures were found to be feasible, the general temporal-spatial models were analysed using the test group mean SL, SP and WR. Accuracy was assessed using the validation group mean values. Individual approximation accuracies showed that the proposed model structure deduced from the linear SL model was suitable for WR approximation. The linear, deduced quadratic and power functions approximated the individual SL, SP and WR, respectively, with high accuracy. Based on the test group mean SL, SP and WR, the general temporal-spatial models were obtained and produced comparable approximation accuracies in the validation group. The general temporal-spatial models predicted well the individual gait parameters with similar individual errors for both groups. These temporal-spatial models clearly describe SL, SP and especially WR at various cadences. They provide accurate reference data for gait estimation and have potential to guide speed modulation in robot-assisted gait rehabilitation. Graphical abstract Twenty-four able-bodied participants (16 in test group and 8 in validation group) walked at seven cadence ratios (CRs), with the individual and group mean stride length (SL), speed (SP) and walk ratio (WR) studied. This work selected the cadence ratio as the independent variable and yielded general temporal-spatial models based on the test group data, which were a linear model for SL, a quadratic function for SP and a power function for WR. The general temporal-spatial model produced comparable approximation accuracies in the validation group. Clearly describing SL, SP and especially WR at various cadences, these temporal-spatial models provide accurate references for gait estimation and have the potential to guide speed modulation in robot-assisted gait rehabilitation. Approximation of the group mean temporal-spatial parameters at seven cadences. Solid lines in parts (a, b): the general linear SL model. Solid lines in (c, d): the general quadratic SP model. Solid lines in (e, f): the general WR model. Dots and stars in (a, c, e): the individual and group mean values for the test group. Dots and stars in (b, d, f): the individual and group mean values for the validation group.


Assuntos
Modelos Biológicos , Velocidade de Caminhada/fisiologia , Caminhada/fisiologia , Adolescente , Adulto , Feminino , Marcha , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Adulto Jovem
16.
ACS Appl Mater Interfaces ; 10(50): 43595-43602, 2018 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-30465429

RESUMO

A recent experiment [ Jin , E. ; Science 2017 , 357 , 673 - 676 ] shows that the conductivity of a two-dimensional (2D) sp2-carbon-hybridized π-conjugated covalent organic framework (sp2-c-COF) can be enhanced by as much as 12 orders of magnitude after iodine oxidation processing. To understand the physical mechanism underlying such a huge increase in the conductivity, we perform multiscale computations and find that the high conductivity of the iodine-oxidized 2D COF can be attributed to both hole transfer and ion transfer within the 2D COF. The computed dominant charge distribution corresponding to the valence band maximum (VBM) suggests that the delocalized π electrons occur mostly at the active reaction sites. The computed low ionization energy at the active reaction sites further supports that the 2D COF tends to lose electrons during iodine oxidation and to yield cationic COF and anionic triiodide I3-. Complementary classical molecular dynamics simulation shows a relatively high anion conductivity of 13.63 × 10-2 S m-1, consistent with the high conductivity measured from the experiment (7.1 × 10-2 S m-1). Meanwhile, we find that the cations in 2D COF can also induce a shift of the Fermi level to cross the valence band, thereby enhancing the hole mobility to 86.75 cm2 V-1 s-1. For proposing a potential application of the highly conductive iodine-oxidized 2D sp2-c-COF, we design a prototypical model of the 2D spirally wound lithium-ion battery and find that it exhibits enhanced stability than a typical electrolyte material.

17.
Chemphyschem ; 19(24): 3380-3387, 2018 12 19.
Artigo em Inglês | MEDLINE | ID: mdl-30335229

RESUMO

The identification of hydrogen evolution reaction (HER) catalysts with high conductivity and high activity is the top priority in the development of renewable energy. Oxygen-terminated Ti2 C (Ti2 CO2 ), as one of the typical MXenes, shows good HER Gibbs free energy (ΔGH ) at low hydrogen coverage, whereas the large band gap of approximately 1.0 eV limits its conductivity capability. By doping phosphor (P) or sulfur (S) to partially substitute the surficial O, the average free energy (ΔGH a ) at various hydrogen coverages has been draggd to approach zero, and the conductivity is also significantly improved by narrowing the band gap to lower than 0.3 eV. Partial charge analysis indicates that doping P or S on the surface induces the diffusion of electrons on oxygen from O 2px to O 2pz , resulting in O 2pz reaction with H 1s. The facial overlapping of H 1s with O 2pz will strengthen the binding strength, hence lowering ΔGH . The energy shift toward Fermi level of Ti 3d after P or S doping contributes to the reduced band gap and high conductivity. Surficial O or P vacancies are created to evaluate the vacancy effect on HER performance, which not only improves ΔGH a and conductivity but also leads to a low reaction barrier of H2 O splitting (<0.2 eV). The armchair nanoribbon (ANR) displays improved HER activity by P-doping at 50% ratio. Our research shows that modification of end-group in MXenes can effectively improve HER catalytic activity and conductivity, which is expected to promote their potential applications in electrocatalysis and energy conversion.

18.
Nanoscale ; 10(29): 13930-13935, 2018 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-30019735

RESUMO

Large-scale hydrogen production through alkaline water electrolysis requires highly active and less expensive materials to replace platinum as a catalyst for the hydrogen evolution reaction (HER). Ruthenium, as the cheapest platinum-group element, has recently been demonstrated to exhibit excellent activity toward the HER. However, achieving better HER activity of ruthenium-based materials by selecting a more active phase is still unexplored. Herein, we report the fabrication of self-supported RuP and RuP2 catalyst films on carbon cloth (RuP/CC and RuP2/CC) via a facile, potentially scalable, and phase-controllable synthetic method. RuP/CC displays superior catalytic activity with a low overpotential of 13 mV at 10 mA cm-1, outperforming RuP2/CC (33 mV at 10 mA cm-1) and most non-Pt HER catalysts. Moreover, good electrochemical stability and faradaic efficiency of nearly 100% are also demonstrated for RuP/CC. Density functional theory calculations reveal that RuP with a higher charge density at the Ru site is more favorable for the chemisorption of hydrogen, thereby exhibiting better HER activity than RuP2.

19.
Zhongguo Ying Yong Sheng Li Xue Za Zhi ; 34(2): 154-158, 2018 Feb 08.
Artigo em Chinês | MEDLINE | ID: mdl-29926681

RESUMO

OBJECTIVES: Investigate the influence of benazepril and amlodipine on the expression of secretin (PZ) and somatostatin (SS) in spontaneously hypertensive rats (SHR). METHODS: Forty-five SHRs (14 weeks old, male) were randomly assigned into 3 groups (n=15):SHR group, Benazepril group (which was given benazepril 0.90 mg·kg-1·d-1) and Amlodipine group (SHRs were given amlodipine 0.45 mg· kg-1·d-1), taking WistarKyoto(WKY) as normal control (n=15), meanwhile, rats in SHR group and WKY group were given the same volume of distilled water. After 8 weeks of intervention, the expression of protein and mRNA of PZ in duodenum and SS in sinuses ventriculi was detected by enzyme-linked immunoassay and RT-PCR. RESULTS: After 8 weeks of intervention, compared with the WKY group, the expression of protein and mRNA of PZ in duodenum and SS in sinuses ventriculi was increased significantly in SHR group (P<0. 05). Compared with SHR group, the expression of PZ in duodenum and SS in sinuses ventriculi was decreased significantly in Benazepril group and Amlodipine group (P<0.05). Compared with Benazepril group, in Amlodipine group the expression of PZ mRNA in duodenum and SS mRNA in sinuses ventriculi was decreased more significantly (P<0.05). CONCLUSIONS: The regulation disorder of PZ in duodenum and SS in sinuses ventriculi exists in SHR. The antihypertensive effect of benazepril and amlodipine may be realized by regulating the expression of PZ and SS, while the regulation of amlodipine is more obvious than benazepril.


Assuntos
Anlodipino/farmacologia , Anti-Hipertensivos/farmacologia , Benzazepinas/farmacologia , Hipertensão/tratamento farmacológico , Secretina/metabolismo , Somatostatina/metabolismo , Animais , Pressão Sanguínea , Masculino , Distribuição Aleatória , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY
20.
Chem Commun (Camb) ; 54(27): 3343-3346, 2018 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-29546907

RESUMO

Ultrasmall ruthenium phosphide nanoparticles grown on reduced graphene oxide nanosheets (Ru2P/RGO-20) are reported as a highly efficient hydrogen evolution reaction (HER) catalyst. It achieves a current density of -10 mA cm-2 at extremely low overpotentials of -22 and -13 mV under acidic and alkaline conditions, respectively, superior to those of commercial Pt/C.

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