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1.
Hepatology ; 80(1): 152-162, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38446707

RESUMO

BACKGROUND AND AIMS: High levels of serum matrix metalloproteinase-7 (MMP-7) have been linked to biliary atresia (BA), with wide variation in concentration cutoffs. We investigated the accuracy of serum MMP-7 as a diagnostic biomarker in a large North American cohort. APPROACH AND RESULTS: MMP-7 was measured in serum samples of 399 infants with cholestasis in the Prospective Database of Infants with Cholestasis study of the Childhood Liver Disease Research Network, 201 infants with BA and 198 with non-BA cholestasis (age median: 64 and 59 days, p = 0.94). MMP-7 was assayed on antibody-bead fluorescence (single-plex) and time resolved fluorescence energy transfer assays. The discriminative performance of MMP-7 was compared with other clinical markers. On the single-plex assay, MMP-7 generated an AUROC of 0.90 (CI: 0.87-0.94). At cutoff 52.8 ng/mL, it produced sensitivity = 94.03%, specificity = 77.78%, positive predictive value = 64.46%, and negative predictive value = 96.82% for BA. AUROC for gamma-glutamyl transferase = 0.81 (CI: 0.77-0.86), stool color = 0.68 (CI: 0.63-0.73), and pathology = 0.84 (CI: 0.76-0.91). Logistic regression models of MMP-7 with other clinical variables individually or combined showed an increase for MMP-7+gamma-glutamyl transferase AUROC to 0.91 (CI: 0.88-0.95). Serum concentrations produced by time resolved fluorescence energy transfer differed from single-plex, with an optimal cutoff of 18.2 ng/mL. Results were consistent within each assay technology and generated similar AUROCs. CONCLUSIONS: Serum MMP-7 has high discriminative properties to differentiate BA from other forms of neonatal cholestasis. MMP-7 cutoff values vary according to assay technology. Using MMP-7 in the evaluation of infants with cholestasis may simplify diagnostic algorithms and shorten the time to hepatoportoenterostomy.


Assuntos
Atresia Biliar , Biomarcadores , Metaloproteinase 7 da Matriz , Humanos , Metaloproteinase 7 da Matriz/sangue , Atresia Biliar/diagnóstico , Atresia Biliar/sangue , Biomarcadores/sangue , Lactente , Feminino , Masculino , Recém-Nascido , Estudos de Coortes , Colestase/diagnóstico , Colestase/sangue , Estudos Prospectivos
2.
Adv Mater ; 36(7): e2309899, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37884393

RESUMO

Sugars are renewable resources essential to human life, but they are rarely used as raw materials for the industrial production of carbon-based materials, especially for the preparation of carbon fiber-reinforced carbon-matrix (C/C) composites, which are extremely useful for the semiconductor and aerospace sectors. Herein, a method utilizing sugar-derived carbon to replace petrochemicals as dense matrix to preparing C/C composites is reported. The matrix from sugar-derived C/C (S-C/C) composites has a nanocrystalline graphite structure that is highly thermally stable and effectively bonded to the carbon fibers. The mechanical properties of the S-C/C composite are comparable to those prepared from petrochemical sources; significantly, it exhibits a linear ablation rate of 0.03 mm s-1 after 200 s of ablation at 3000 °C in 10 MW m-2 heat flux. This new class of S-C/C is promising for use in a broad range of fields, ranging from semiconductor to aerospace.

3.
Small ; 20(23): e2308145, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38150646

RESUMO

Carbon fiber composites have great application prospects as a potential electromagnetic (EM) wave-absorbing material, yet it remains extremely challenging to integrate multiple functions of EM wave absorption, mechanical strength, thermal insulation, and flame retardancy. Herein, a novel carbon fiber reinforced C/SiOC aerogel (CF/CS) composite is successfully prepared by sol-gel impregnation combined with an ambient drying process for the first time. The density of the obtained CF/CS composites can be controlled just by changing sol-gel impregnation cycles (original carbon fiber felt (S0), and samples with one (S1) and two (S2) impregnation cycles are 0.249, 0.324, and 0.402 g cm-3, respectively), allowing for efficient tuning of their properties. Remarkably, S2 displays excellent microwave absorption properties, with an optimal reflection loss of -65.45 dB, which is significantly improved than S0 (-10.90 dB). Simultaneously, compared with S0 (0.75 and 0.30 MPa in the x/y and z directions), the mechanical performance of S2 is dramatically improved with a maximum compressive strength of 10.37 and 4.93 MPa in the x/y and z directions, respectively. Moreover, CF/CS composites show superior thermal insulation capability than S0 and obtain good flame-retardant properties. This work provides valuable guidance and inspiration for the development of multifunctional EM wave absorbers.

4.
J Antimicrob Chemother ; 78(2): 478-487, 2023 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-36545869

RESUMO

BACKGROUND: Piperacillin/tazobactam, a commonly used antibiotic, is associated with acute kidney injury (AKI). The relationship between piperacillin concentrations and AKI remains unknown. OBJECTIVE: Estimate piperacillin exposures in critically ill children and young adults administered piperacillin/tazobactam to identify concentrations and clinical factors associated with piperacillin-associated AKI. PATIENTS AND METHODS: We assessed piperacillin pharmacokinetics in 107 patients admitted to the paediatric ICU who received at least one dose of piperacillin/tazobactam. Piperacillin AUC, highest peak (Cmax) and highest trough (Cmin) in the first 24 hours of therapy were estimated. Piperacillin-associated AKI was defined as Kidney Disease: Improving Global Outcomes (KDIGO) Stage 2/3 AKI present >24 hours after initial piperacillin/tazobactam dose. Likelihood of piperacillin-associated AKI was rated using the Naranjo Adverse Drug Reaction Probability Scale. Multivariable logistic regression was performed to identify patient and clinical predictors of piperacillin-associated AKI. RESULTS: Out of 107 patients, 16 (15%) were rated as possibly or probably having piperacillin-associated AKI. Estimated AUC and highest Cmin in the first 24 hours were higher in patients with piperacillin-associated AKI (2042 versus 1445 mg*h/L, P = 0.03; 50.1 versus 10.7 mg/L, P < 0.001). Logistic regression showed predictors of piperacillin-associated AKI included higher Cmin (OR: 5.4, 95% CI: 1.7-23) and age (OR: 1.13, 95% CI: 1.05-1.25). CONCLUSIONS: We show a relationship between estimated piperacillin AUC and highest Cmin in the first 24 hours of piperacillin/tazobactam therapy and piperacillin-associated AKI, suggesting total piperacillin exposure early in the course is associated with AKI development. These data could serve as the foundation for implementation of model-informed precision dosing to reduce AKI incidence in patients given piperacillin/tazobactam.


Assuntos
Injúria Renal Aguda , Piperacilina , Criança , Adulto Jovem , Humanos , Piperacilina/efeitos adversos , Vancomicina , Estudos Retrospectivos , Quimioterapia Combinada , Antibacterianos/efeitos adversos , Combinação Piperacilina e Tazobactam/efeitos adversos , Tazobactam/efeitos adversos , Injúria Renal Aguda/induzido quimicamente , Ácido Penicilânico/efeitos adversos
5.
Adv Mater ; 34(31): e2200363, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35686916

RESUMO

Obtaining large plastic deformation in polycrystalline van der Waals (vdW) materials is challenging. Achieving such deformation is especially difficult in graphite because it is highly anisotropic. The development of sugar-derived isotropic nanostructured polycrystalline graphite (SINPG) is discussed herein. The structure of this material preserves the high in-plane rigidity and out-of-plane flexibility of graphene layers and enables prominent plasticity by activating the rotation of nanoscale (5-10 nm) grains. Thus, micrometer-sized SINPG samples demonstrate enhanced compressive strengths of up to 3.0 GPa and plastic strains of 30-50%. These findings suggest a new pathway for enabling plastic deformation in otherwise brittle vdW materials. This new class of nanostructured carbon materials is suitable for use in a broad range of fields, from semiconductor to aerospace applications.

6.
J Neurosci ; 42(14): 2885-2904, 2022 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-35197315

RESUMO

Oxytocin (OXT) neurons in paraventricular nucleus of hypothalamus (PVN) are involved in modulating multiple functions, including social, maternal, feeding, and emotional related behaviors. PVN OXT neurons are canonically classified into magnocellular (Magno) and parvocellular (Parvo) subtypes. However, morpho-electric properties and the diversity of PVN OXT neurons are not well investigated. In this study, we profiled the morpho-electric properties of PVN OXT neurons by combining transgenic mice, electrophysiological recording, morphologic reconstruction, and unsupervised clustering analyses. Total 224 PVN OXT neurons from 23 mice were recorded and used for analyses in this study, and 29 morpho-electric parameters were measured. Magno and Parvo OXT neurons have prominent differences in their morpho-electric features, and PVN OXT neurons in male and female mice share similar neuronal properties. Some morpho-electric features of PVN OXT neurons, especially Magno neurons, exhibit significant diverse changes along the rostral-caudal axis. Furthermore, we find that PVN OXT neurons are classified into at least six subtypes based on their morpho-electric properties via unsupervised clustering. Only one Magno-Parvo mixed subtype in posterior PVN subregion, but not the other five subtypes, showed significant neuronal activity change in different feeding conditions. Our study supports the diversity of PVN OXT neurons and subtle neuron classification will promote excavating the functions of oxytocinergic system.SIGNIFICANCE STATEMENT Oxytocin (OXT) is well known for its function in labor induction, but it also plays multiple roles in social, feeding, and emotional behaviors via modulating different brain regions. Paraventricular nucleus of hypothalamus (PVN) OXT neurons are traditionally classified into magnocellular and parvocellular. However, functional and single-cell transcriptomic studies indicate that OXT neurons should be further classified. Here, we thoroughly investigated the morpho-electric properties and spatial distribution of PVN OXT neurons, and find that OXT neurons have at least six subtypes based on their morpho-electric features. Among these six subtypes, only one magnocellular-parvocellular mixed subtype, which are distributed in the posterior PVN subregion, change their activities with different feeding states. Our study uncovers the diversity of PVN OXT neurons and suggests the necessary of subtle neuronal classification.


Assuntos
Neurônios , Ocitocina , Núcleo Hipotalâmico Paraventricular , Animais , Feminino , Hipotálamo , Masculino , Camundongos , Neurônios/fisiologia , Ocitocina/fisiologia , Núcleo Hipotalâmico Paraventricular/fisiologia , Ratos , Ratos Wistar
7.
J Colloid Interface Sci ; 582(Pt B): 552-560, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32911404

RESUMO

The development of high-performance flexible supercapacitor using biomass wastes as raw materials to overcome the high manufacturing cost has attracted excellent interest. Herein, a hierarchical structure of carbon nanorods supported hydrothermal carbons and carbon fibers (CNR/HTC/CFs) with superior electrochemical performance as well as high strength is successfully designed for the first-time using waste straw as a sustainable and economic carbon resource. The straw pyrolysis gases after purification are introduced to support the formation of high specific surface area CNRs via a simple vapor phase growth process. The CNR/HTC/CFs exhibit high mass specific capacitance of 269.47 F g-1 under the scan rate of 3 mV s-1 in three-electrode system. A high energy density of 15.54 Wh kg-1 with the power density of 0.49 kW kg-1 was obtained in the as-assembled all solid-state supercapacitor device with gel electrolyte, whose value retains as high as 6.99 Wh kg-1 with the power density of 10.01 kW kg-1. The tensile strength of the finally fibers can reach up to 2743 ± 467 MPa, which is sufficient for many practical industrial applications. This work provides a feasible synthetic strategy using sustainable biomass waste as raw materials to prepare high strength and capacitance energy storage devices.


Assuntos
Carbono , Nanotubos , Biomassa , Fibra de Carbono , Capacitância Elétrica
8.
J Colloid Interface Sci ; 582(Pt A): 270-282, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32823128

RESUMO

Excellent electromagnetic wave (EMW) absorbing materials with high-temperature stable and superior mechanical properties are among the most promising candidates for practical application. Here, novel hydrothermal carbon coated three-dimensional (3D) needled carbon fiber reinforced silicon-boron carbonitride (HC-CF/SiBCN) composites with a hierarchical A (CF)/B (HC)/C (SiBCN) structure were constructed and prepared for the first time by combining hydrothermal transformation and precursor infiltration and pyrolysis (PIP) process. The thickness of the HC coating controlled by the glucose concentration played a crucial role in tailoring the EMW capacity of the composite. The incorporation of SiBCN could not only effectively improve the oxidation resistance but also actively enhance the mechanical properties of the HC coated CF structure. Compared to the weak high-temperature oxidation resistance and mechanical properties of pristine 3D needled CF felt, the composites after the introduction of HC and SiBCN were thermostable in air atmosphere beyond 1000 °C to about above 70% weight retention, and the maximum flexural and compression strength of the composites could reach to 23.51 ± 1.37 and 12.22 ± 1.12 MPa, respectively. A substantial enhancement of EMW absorption ability was achieved through incorporation of HC and SiBCN, which could be attributed to the matched characteristic impedance and enhanced loss ability, whose optimization EMW absorption performance was the minimum reflection loss (RLmin) of -52.08 dB and effective absorption bandwidth (EAB) of 7.64 GHz for the composite obtained by two PIP cycles with 24 wt% glucose solution, demonstrating that the HC-CF/SiBCN composites with high-temperature stable, excellent mechanical and superior EMW absorption properties could be considered as a promising candidate for the applications in harsh environments.

9.
Chem Commun (Camb) ; 56(53): 7249-7252, 2020 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-32467954

RESUMO

A thermal-sensitive "jelly" was used to control the diffusion of a diamine monomer for synthesizing polyamide free-standing nanofilms with an adjustable thickness of 5-35 nm. The reduced reaction rate of the interfacial polymerization at the hexane-"jelly" interface made the synthesized nanofilms show high water permeation flux and suitable salt rejection, and they also have highly negative surface charges and fairly smooth surfaces.

10.
Chin J Nat Med ; 18(3): 211-218, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32245591

RESUMO

Cholestasis is caused by the obstacle of bile formation or secretion and can develop into severe liver diseases. We previously reported the ethanol extract of Schisandra sphenanthera (Wuzhi tablet, WZ) can significantly protect against lithocholic acid (LCA)-induced intrahepatic cholestasis in mice, partially due to the activation of PXR pathway and promotion of liver regeneration. However, the effect of WZ on the bile acids profile and gut microbiome in cholestastic mice remain unknown. In this study, the effect of WZ against LCA-induced liver injury was evaluated and its effect on the bile acids metabolome and gut microbiome profiles in cholestastic mice was further investigated. Targeted metabolomics analysis was performed to examine the change of bile acids in the serum, liver, intestine and feces. The change of intestinal flora were detected by the genomics method. Targeted metabolomics analysis revealed that WZ enhanced the excretion of bile acids from serum and liver to intestine and feces. Genomics analysis of gut microbiome showed that WZ can reverse LCA-induced gut microbiome disorder to the normal level. In conclusion, WZ protects against LCA-induced cholestastic liver injury by reversing abnormal bile acids profiles and alteration of gut microbiome.


Assuntos
Ácidos e Sais Biliares/metabolismo , Colestase/tratamento farmacológico , Medicamentos de Ervas Chinesas/farmacologia , Microbioma Gastrointestinal , Extratos Vegetais/farmacologia , Animais , Doença Hepática Induzida por Substâncias e Drogas/tratamento farmacológico , Colestase/induzido quimicamente , Ácido Litocólico , Masculino , Metaboloma , Camundongos , Camundongos Endogâmicos C57BL , Schisandra/química , Comprimidos
11.
J Colloid Interface Sci ; 568: 106-116, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32088441

RESUMO

High-performance microwave absorption materials combined with good oxidation resistance and mechanical properties are highly desirable in some extreme situations. Herein, three-dimensional (3D) needled carbon fiber felts reinforced silicon oxycarbide (SiOC/CFs) composites with excellent electromagnetic (EM) wave absorption, good oxidation resistance and mechanical properties were successfully prepared through a simple precursor infiltration and pyrolysis (PIP) process. Notably, the EM wave absorption, oxidation resistance and mechanical performances strongly depend on the PIP cycles through adjusting the content of SiOC to control the porosity and density of the composites. A substantial enhancement of EM wave absorption performance of composites is achieved via incorporation of SiOC with different PIP cycles, resulting from the matched characteristic impedance and enhanced loss ability. The minimum reflection loss (RLmin) of pure carbon fiber felts is -8.4 dB, whose value is decreased to -62.9 dB for the composites with 1 PIP cycle, and to -49.9 dB for the composites with 2 PIP cycles, respectively. The results indicate that the as-prepared SiOC/CFs composites with superior EM wave absorption, great oxidation resistance and mechanical properties could be considered as a great potential for the applications in harsh environments.

12.
J Colloid Interface Sci ; 559: 186-196, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31627142

RESUMO

MnO nanoparticles (MnONP) decorated SiC whiskers (SiCw) with superior electromagnetic (EM) wave absorption performances were successfully synthesized by combining a hydrothermal and thermal annealing process. The microstructural feature and the content of MnONP of these MnONP/SiCw composites could be effectively controlled by the hydrothermal temperature, resulting in the adjustable EM wave absorption capacity. Compared with the poor EM wave absorption property of pristine SiCw (-10.48 dB), the MnONP/SiCw heterostructures achieve substantially enhanced microwave absorption performances, attributing to the suitable impedance matching and improved loss ability arose from the synergetic effect between MnO and SiC, whose minimum reflection loss (RLmin) is improved to -15.84 dB for MnONP/SiCw obtained at 80 °C (S-80), to -15.17 dB for MnONP/SiCw obtained at 100 °C (S-100), and to -55.10 dB for MnONP/SiCw obtained at 120 °C (S-120), respectively. The MnONP/SiCw composite not only exhibits enhanced microwave absorption property, but also presents wider effective absorption bandwidth (EAB), reaching up to 5.4 GHz for S-80, 3.6 GHz for S-100 and 5.2 GHz for S-120 in comparison with pristine SiC (1.5 GHz). This work is expected to provide an effective approach to enhance EM wave absorption property of dielectric materials by incorporation of MnO and the MnONP/SiCw composites could be as a promising candidate for EM wave absorption applications.

13.
J Colloid Interface Sci ; 559: 263-272, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31634670

RESUMO

Tremendous efforts have been dedicated to developing sorbents for water remediation due to their high efficiency and non-secondary pollution. However, the majority of sorbents still face the challenges of complex processing, low mechanical strength and volume absorption. Hence, the functional hydrothermal carbonization coatings (HTCCs) were prepared on carbon fibers in carbon fiber braid via a facile hydrothermal carbonization process of widely sourced carbohydrate to obtain a robust sorbent, which possessed the controllable microstructure and composition for various requirements of water remediation. The gradient surface structure of carbon fiber braid with interior smooth coatings carbon fibers and exterior rough surface could be fabricated at pH value of 1. The HTCCs-carbon fiber braid had superior yield strength and compressive strength. By regulating the reaction process, the yield strength could range from 0.044 MPa to 0.235 MPa and the max compressive strength change from 0.198 MPa to 1.113 MPa. The HTCCs-carbon fiber braid showed excellent adsorption for Rhodamine B with a high removal degree of 98.5%, which kept more than 90% even after 10 squeezing adsorption cycles. The HTCCs-carbon fiber braid could be adjusted to effectively absorb oil pollutants from water by a facile heat treatment. After heat treatment, the HTCCs-carbon fiber braid exhibited excellent volume absorption capacity for contaminants, which could change from 83.9% to 88.5%. Thus, the HTCCs-carbon fiber braid prepared by a green, high-efficiency and low-cost process has great potential for sorption multiple contaminations in water by virtue of the combination of controllable carbonaceous coatings and robust carbon fiber braid.

14.
Polymers (Basel) ; 11(3)2019 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-30960518

RESUMO

Responsive polymer-based sensors have attracted considerable attention due to their ability to detect the presence of analytes and convert the detected signal into a physical and/or chemical change. High responsiveness, fast response speed, good linearity, strong stability, and small hysteresis are ideal, but to gain these properties at the same time remains challenging. This paper presents a facile and efficient method to improve the photonic sensing properties of polymeric gels by using non-close-packed monolayer colloidal crystals (ncp MCCs) as the template. Poly-(2-vinyl pyridine) (P2VP), a weak electrolyte, was selected to form the pH-responsive gel material, which was deposited onto ncp MCCs obtained by controlled O2 plasma etching of close-packed (cp) MCCs. The resultant ultrathin photonic polymer gel film (UPPGF) exhibited significant improvement in responsiveness and linearity towards pH sensing compared to those prepared using cp MCCs template, achieving fast visualized monitoring of pH changes with excellent cyclic stability and small hysteresis loop. The responsiveness and linearity were found to depend on the volume and filling fraction of the polymer gel. Based on a simple geometric model, we established that the volume increased first and then decreased with the decrease of template size, but the filling fraction increased all the time, which was verified by microscopy observations. Therefore, the responsiveness and linearity of UPPGF to pH can be improved by simply adjusting the etching time of oxygen plasma. The well-designed UPPGF is reliable for visualized monitoring of analytes and their concentrations, and can easily be combined in sensor arrays for more accurate detection.

15.
Biomed Pharmacother ; 114: 108851, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30965234

RESUMO

Pulmonary fibrosis is the final outcome of a variety of diffuse pulmonary interstitial diseases, and it has an unclear pathogenesis. There is no effective drug treatment, so the clinical prognosis is poor. As an effective component of ginseng, total ginsenoside (TG) inhibits acute lung injury. This study determined whether TG has protective effects on pulmonary fibrosis and investigated its protective mechanisms. A pulmonary fibrosis model in BALB/c mice was established by injecting the bleomycin chemotherapeutic agent into the trachea. TG (40, 80, and 160 mg/kg/d) was given continuously for 28 days from the second day after development of the model. Pulmonary fibrosis was determined by measuring the lung coefficient, haematoxylin and eosin, and Masson's trichrome staining of lung samples, and detection of alpha smooth muscle actin expression in lung tissues. To investigate the mechanisms of anti-pulmonary fibrosis by TG, we detected the genes and proteins of the transforming growth factor-ß1 (TGF-ß1)/Smad signalling pathway and matrix metalloproteinase (MMP) system. Treatment with TG (40, 80, and 160 mg/kg/d) ameliorated pulmonary fibrosis induced by bleomycin in mice, downregulated the expression of TGF-ß1, Smad2, Smad3, MMP-2, MMP-9, and tissue inhibitor of metalloproteinase-1, and upregulated the protein expression of Smad7. These results suggest that the protective effects of TG on pulmonary fibrosis induced by bleomycin are related to regulation of the TGF-ß1/Smad signalling pathway and MMP system.


Assuntos
Bleomicina/farmacologia , Ginsenosídeos/farmacologia , Fibrose Pulmonar/tratamento farmacológico , Transdução de Sinais/efeitos dos fármacos , Animais , Regulação para Baixo/efeitos dos fármacos , Feminino , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Fibrose Pulmonar/metabolismo , Fator de Crescimento Transformador beta1/metabolismo , Regulação para Cima/efeitos dos fármacos
16.
ACS Appl Mater Interfaces ; 11(8): 7936-7945, 2019 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-30722660

RESUMO

Rational design and preparation of electrocatalyst with optimal component and interfaces, which can work well for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline media, are of great importance in practical water splitting. Herein, a multiscale structure surface engineering approach to construct Co(OH)2/Ag/FeP hybrid as efficient electrocatalysis for water splitting in alkaline media is reported. By optimizing the component ratio and engineering interfacial structure, the Co(OH)2/Ag/FeP hybrid eletrocatalyst exhibits promoted HER and OER activity as well as stability in alkaline media, achieving an overpotential of 118 and 236 mV at a current density of 10 mA cm-2, respectively. Further experimental characterizations demonstrate the electron structure changes in Co(OH)2/Ag/FeP hybrid after constructing the interfaces, which is beneficial to generate low-charge state Fe2+ and high-oxidized Co3+/4+. The first-principle calculations reveal that the dissociation of H2O at the interface region is energetically favorable, which is responsible for the enhanced HER and OER activity. Furthermore, two-electrode alkaline water electrolyzer constructed by Co(OH)2/Ag/FeP hybrid electrocatalysts only requires a voltage of 1.56 V to afford a current density of 10 mA cm-2, which is superior to the commercial Pt/C-IrO2 catalytic couple and makes it a promising material to be employed as effective bifunctional catalysts for overall water splitting.

17.
ChemSusChem ; 11(23): 4150-4155, 2018 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-30303629

RESUMO

Co9 S8 crystals can catalyze the growth of thin-walled graphite microtubes (GMTs) through a catalytic chemical vapor deposition (CCVD) process using thiourea as the precursor. The growth of GMTs follows a tip-growth mechanism with tube diameters up to a few micrometer. The hollow interiors of the GMTs are filled with carbon nanotubes and wrinkled graphene layers, which form a unique nanotube/graphene-in-microtube structure. As-formed GMTs are N,S-codoped with lots of Co9 S8 nanoparticles encapsulated in their inner walls. These GMTs are room-temperature ferromagnets and can be loaded on Ni foams to work as binder-free electrocatalysts with low overpotential (310 mV at 50 mA cm-2 for the oxygen evolution reaction (OER) and 284 mV at 50 mA cm-2 for the hydrogen evolution reaction (HER)) and long-term durability (continuous work for 120 h without loss in performance). Our research proves that metal sulfides can catalyze the growth of graphite microtubes and as-formed GMTs may potentially be used as functional building blocks to construct new kinds of electrochemical devices for various energy-related applications.

18.
Ying Yong Sheng Tai Xue Bao ; 29(6): 1943-1850, 2018 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-29974705

RESUMO

To investigate the effects of drought stress on the growth of sweet potato, photosynthesis, yield, and water consumption characteristics were investigated in field-grown sweet potato plants (Jishu 21, a drought-tolerant cultivar) at different growth stages in 2014-2015. There were five drought treatments, including the whole growth period (DS), the early stage of growth (rooting and branching period, DS1), the middle stage of growth (storage root initiation period, DS2), and the late stage of growth (storage root bulking period, DS3), and a normal irrigation treatment (WW) as control. The results showed that sweet potato plants in DS significantly decreased in dry mass, biomass, and harvest index during two years. The biomass of sweet potato under DS, DS1, DS2 and DS3 was decreased by 31.3%, 21.2%, 19.6% and 7.7%; the harvest index was decreased by 19.9%, 14.5%, 14.1% and 6.5%, and the dry mass was decreased by 45.3%, 33.1%, 31.3% and 14.2%, respectively. The leaf area index in DS, DS1, DS2 and DS3 was decreased by 77.1%, 60.1%, 39.2% and 17.1% at 100 days after transplanting (DAT), and the net photosynthesis was decreased by 56.7%, 26.6%, 18.7% and 9.5% at 90 DAT, respectively. Plants under drought stress reduced diurnal evaporation, transpiration rate, water consumption, daily water consumption, and soil water use efficiency, but increased irrigation water use efficiency. Drought stress decreased leaf area index, Pn, biomass and the allocation of biomass to storage root, resulting in a significant reduction of yield. The early drought and the long stress duration had significant impacts on leaf area index, Pn, biomass and harvest index, leading to a greater reduction in yield and water use efficiency. Therefore, drought stress at the early growth stages of sweet potato should be avoided during cultivation.


Assuntos
Secas , Ipomoea batatas/fisiologia , Fotossíntese , Biomassa , Folhas de Planta , Água
19.
J Pharm Pharmacol ; 70(8): 1048-1058, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29770446

RESUMO

OBJECTIVES: To investigate the antitumour property of tetrandrine by inducing autophagy and apoptosis in human gastric cancer cells, and to explore the potential molecular mechanisms. METHODS: The antitumour activity of tetrandrine was assessed through MTT assay. Apoptosis was measured by flow cytometry and microscopic examination of cellular morphology. The mitochondrial membrane potential was detected by staining with Rh-123. Induction of autophagy was monitored by transmission electron microscopy observation, using GFP-LC3 transfection. KEY FINDINGS: The results revealed that tetrandrine exhibits significant antitumour activity against gastric human cancer cell and the antigastric tumour activity was depended on inducing autophagy and apoptosis through upregulating the apoptosis-related protein (cleaved PARP, cleaved caspase-3 and cleaved caspase-9) and autophagy-related protein (Beclin-1, LC3-II and p62), and decreasing the phosphorylation of AKT/mTOR, PS6K and P-4EBP1. Adding the inhibitor of autophagy, 3-MA or Baf-A1, increased the viability of tetrandrine-exposed gastric cancer cells, which confirmed the role of autophagy played in the gastric cancer cell death induced by tetrandrine. CONCLUSIONS: These results demonstrated that the antitumour effects of tetrandrine by inducing autophagy and apoptosis involving Akt/mTOR pathway. Thus, tetrandrine may be a promising lead compound to be further developed in future for cancer therapy.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Benzilisoquinolinas/farmacologia , Proliferação de Células/efeitos dos fármacos , Neoplasias Gástricas/patologia , Antineoplásicos Fitogênicos/isolamento & purificação , Benzilisoquinolinas/isolamento & purificação , Técnicas de Cultura de Células , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Estrutura Molecular , Proteínas Proto-Oncogênicas c-akt/metabolismo , Stephania tetrandra/química , Serina-Treonina Quinases TOR/metabolismo
20.
ACS Appl Mater Interfaces ; 10(2): 1701-1706, 2018 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-29271199

RESUMO

Owing to its benefits to reducing paper production and consumption, ink-free rewritable paper has attracted great attention and it is desirable to develop rewritable paper based on its low-cost, robust, and environmentally benign color switching systems. Herein, we report the fabrication of a rewritable paper based on novel poly(vinylpyrrolidone)/hexatungstic acid (HTA) hybrids with fast dual-mode color switching. As-prepared rewritable paper shows fast and reversible colorless-blue or blue-colorless color switching upon photo- or hydroprinting, owing to the fast redox transformations of the unique HTA clusters. More interestingly, the rewritable paper can be used as a template for noble-metal reduction and the noble metal can be deposited on the reduced area of the paper to form well-ordered patterns in high resolution. This rewritable paper can be produced in large scale, and the composition can be facilely tuned with various polyoxometalates or polymers. It may not only be an attractive alternative to current paper prints but also be potentially used for noble-metal reduction to prepare photolithographic circuits and optoelectronic devices.

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