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1.
Talanta ; 235: 122818, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517674

RESUMO

As a type of environmental endocrine disrupting chemicals, bisphenols (BPs) have a certain embryonic toxicity and teratogenicity, which can significantly increase the risks of breast cancer, prostate cancer, leukemia and other cancers. In this work, stable multivariate metal-organic frameworks (UiO-66-NH2/TCPPx) were synthesized via in situ one-pot method and used as miniaturized dispersive solid-phase extraction (dµSPE) sorbents for extraction of trace BPs from environmental samples. The phase purity, crystal morphology and physical properties of UiO-66-NH2/TCPPx samples were varied by adjusting the mass ratio of TCPP. The extraction performance of UiO-66-NH2/TCPPx samples were investigated and UiO-66-NH2/TCPP1.0 exhibited the highest adsorption efficiency. Besides, UiO-66-NH2/TCPP1.0 possessed excellent recycling stability for the adsorption and desorption of BPs more than 20 cycles. The experimental parameters including amount of adsorbent, adsorption time, sample solution pH, temperature, desorption time and desorption solvents which affecting the efficiency of dµSPE were studied, respectively. Good linearity (R2 > 0.9992) in range of 0.1-200 ng mL-1 was obtained. The detection limits (S/N = 3) and quantification limits (S/N = 10) were achieved at 0.03-0.08 ng mL-1 and 0.1-0.5 ng mL-1, respectively. The relative standard deviations (RSDs) of intra-day and inter-day ranged from 2.5 to 5.5% and 1.1-6.8%. Enrichment factors were calculated in the range of 303-338. The obtained recoveries of bisphenol F (BPF), bisphenol A (BPA), bisphenol B (BPB) and bisphenol AF (BPAF) were 81.26-91.03% (RSDs = 0.96-6.47%), 82.2-97.27% (RSDs = 0.45-6.15%), 87.56-97.26% (RSDs = 1.1-6.22%) and 82.2-100.8% (RSDs = 0.46-4.07%). The UiO-66-NH2/TCPP1.0 can be employed as potential dµSPE sorbents for the enrichment of trace BPs in the environmental samples.


Assuntos
Estruturas Metalorgânicas , Adsorção , Compostos Benzidrílicos , Humanos , Masculino , Fenóis , Extração em Fase Sólida , Solventes
2.
Chem Commun (Camb) ; 57(70): 8810-8813, 2021 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-34382969

RESUMO

Herein, a new gas-cycle-assisted (GCA) headspace solid-phase microextraction (HS-SPME) device was designed to rapidly extract organic pollutants with high Kow and boiling points, which have difficulty in volatilization from matrix to headspace. Organic pollutants, including three polycyclic aromatic hydrocarbons (PAHs), four polychlorinated biphenyls (PCBs), and five phthalate esters (PAEs), were selected to evaluate the performance of GCA HS-SPME. Compared with conventional HS-SPME, the equilibrium times of GCA HS-SPME for extraction of PAHs, PCBs, and PAEs were greatly shortened from 70-90 to 5-11 min. Moreover, the limits of detection for analysis of PAHs were achieved at pg mL-1 level by GCA HS-SPME coupled with gas chromatography-flame ionization detection.

3.
Educ Technol Res Dev ; : 1-24, 2021 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-34366635

RESUMO

The main purpose of this study was to examine the critical factors influencing university teachers' use of a mobile technology-enhanced teaching (MTT) platform during the new coronavirus (COVID-19) epidemic. An integrated model with multiple factors drawing from the theoretical models and learning theories was proposed in this study to examine university teachers' intentions to use an MTT platform. The multiple factors included the individual factor (e.g., growth mindset, help seeking, and self-efficacy), the social factor (e.g., social norms), and the technological acceptance factor (e.g., perceived usefulness and perceived ease of use). The survey method was used to collect data on university teachers' perceptions of the MTT platform use, and a two-step structural equation modeling approach was used for the data analysis. Based on the path analysis of a total of 214 valid responses, the results identified that growth mindset, help seeking, and self-efficacy from the individual factor, as well as perceived usefulness from the technology acceptance factor were the significant determinants of university teachers' intentions to adopt the MTT. The contributions of this study are twofold. First, the proposed model was derived from multiple literature sources, providing a sound theoretical foundation to understand MTT platform use from an academic angle. Second, university teachers' viewpoints are a unique observation of their actual platform use, providing practical insights into the improvement and maintenance of MTT-related platforms for all educators. The findings are especially valuable during the post-COVID-19 era.

4.
Molecules ; 26(13)2021 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-34202856

RESUMO

Banana is a major fruit crop throughout the world with abundant lignocellulose in the pseudostem and rachis residues for biofuel production. In this study, we collected a total of 11 pseudostems and rachis samples that were originally derived from different genetic types and ecological locations of banana crops and then examined largely varied edible carbohydrates (soluble sugars, starch) and lignocellulose compositions. By performing chemical (H2SO4, NaOH) and liquid hot water (LHW) pretreatments, we also found a remarkable variation in biomass enzymatic saccharification and bioethanol production among all banana samples examined. Consequently, this study identified a desirable banana (Refen1, subgroup Pisang Awak) crop containing large amounts of edible carbohydrates and completely digestible lignocellulose, which could be combined to achieve the highest bioethanol yields of 31-38% (% dry matter), compared with previously reported ones in other bioenergy crops. Chemical analysis further indicated that the cellulose CrI and lignin G-monomer should be two major recalcitrant factors affecting biomass enzymatic saccharification in banana pseudostems and rachis. Therefore, this study not only examined rich edible carbohydrates for food in the banana pseudostems but also detected digestible lignocellulose for bioethanol production in rachis tissue, providing a strategy applicable for genetic breeding and biomass processing in banana crops.


Assuntos
Biocombustíveis , Biomassa , Temperatura Alta , Lignina/química , Musa/química , Água , Hidrólise
5.
Carbohydr Polym ; 265: 118070, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-33966834

RESUMO

Potato is a major food crop with enormous biomass straw, but lignocellulose recalcitrance causes a costly bioethanol conversion. Here, we selected the cytochimera (Cyt) potato samples showing significantly-modified lignocellulose and much increased soluble sugars and starch by 2-4 folds in mature straws. Under two pretreatments (8 min liquid hot water; 5% CaO) at minimized conditions, the potato Cyt straw showed complete enzymatic saccharification. Further performing yeast fermentation with all hexoses released from soluble sugars, starch and lignocellulose in the Cyt straw, this study achieved a maximum bioethanol yield of 24 % (% dry matter), being higher than those of other bioenergy crops as previously reported. Hence, this study has proposed a novel mechanism model on the reduction of major lignocellulose recalcitrance and regulation of carbon assimilation to achieve cost-effective bioethanol production under optimal pretreatments. This work also provides a sustainable strategy for utilization of potato straws with minimum waste release.


Assuntos
Biocombustíveis , Etanol/metabolismo , Lignina/química , Solanum tuberosum/química , Amido/química , Biomassa , Celulase/metabolismo , Celulose/química , Produtos Agrícolas/química , Etanol/química , Fermentação , Hidrólise , Lignina/metabolismo , Poliploidia , Saccharomyces cerevisiae/metabolismo , Solanum tuberosum/genética , Amido/metabolismo
7.
Pharmacol Biochem Behav ; 203: 173128, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33515585

RESUMO

The molecular and behavioral aspects of α-pyrrolidinopentiophenone (α-PVP) have been characterized; however, how the structural modification of α-PVP affects its abuse potential is still unknown. In this study, we investigated the abuse potential of two pyrrolidinylated second-generation cathinones:4-chloro-α-pyrrolidinopentiophenone (4cl-α-PVP) and 4-chloro-α-pyrrolidinopropiophenone (4cl-α-PPP). Male Sprague-Dawley rats were trained to self-administer methamphetamine (METH, 0.05 mg·kg-1·infusion-1), α-PVP (0.05 mg·kg-1·infusion-1), 4cl-α-PVP (0.05 mg·kg-1·infusion-1), and 4cl-α-PPP (0.5 mg·kg-1·infusion-1) under a fixed ratio (FR) 1 reinforcement schedule for 10 sessions. The discriminative-stimulus effect of METH (0.8 mg/kg) from saline was tested under an FR10 schedule of food delivery. α-PVP, 4cl-α-PVP and 4cl-α-PPP produced reinforcement behaviors and presented an inverted U-shaped dose effect. The reinforcing potency was displayed with a rank order of α-PVP (0.029 mg·kg-1·infusion-1) > METH (0.040 mg·kg-1·infusion-1) > 4cl-α-PVP (0.094 mg·kg-1·infusion-1) > 4cl-α-PPP (0.51 mg·kg-1·infusion-1). All three drugs were fully substituted for the discriminative-stimulus effects of METH in rats. The substitution potency for discriminative-stimulus effects of α-PVP (ED50 = 0.4 mg/kg) was approximately equal to that of METH (ED50 = 0.3 mg/kg), while the discriminative potency of 4cl-α-PVP (ED50 = 1.0 mg/kg) and 4cl-α-PPP (ED50 = 5 mg/kg) was approximately 3 and 16-fold less than that of METH. The rank order of potency was α-PVP ≈ METH >4cl-α-PVP > 4cl-α-PPP. The present data demonstrated that 4cl-α-PVP and 4cl-α-PPP produced reinforcing effects and fully and dose-dependently substituted for the subjective effects of METH, suggesting that both 4cl-α-PVP and 4cl-α-PPP have abuse potential that may be similar to METH.


Assuntos
Alcaloides/administração & dosagem , Estimulantes do Sistema Nervoso Central/administração & dosagem , Drogas Desenhadas/administração & dosagem , Metanfetamina/administração & dosagem , Pentanonas/administração & dosagem , Propiofenonas/administração & dosagem , Pirrolidinas/administração & dosagem , Reforço Psicológico , Alcaloides/efeitos adversos , Animais , Estimulantes do Sistema Nervoso Central/efeitos adversos , Condicionamento Operante/efeitos dos fármacos , Drogas Desenhadas/efeitos adversos , Relação Dose-Resposta a Droga , Drogas Ilícitas , Masculino , Pentanonas/efeitos adversos , Propiofenonas/efeitos adversos , Pirrolidinas/efeitos adversos , Ratos , Ratos Sprague-Dawley , Autoadministração , Transtornos Relacionados ao Uso de Substâncias/etiologia
8.
Sci Total Environ ; 759: 143480, 2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33213920

RESUMO

The consumption or prevalence of acesulfame, caffeine, paracetamol and amantadine was estimated by wastewater-based epidemiology based on a multi-parameter population model in 20 sewage treatment plants (STPs) in Hebei province, China. To minimize the uncertainties contributed by population estimation in WBE, a multi-parameter population model was established based on the population biomarkers equivalent population and flow volume-population with the weight factors calculated by the analytic hierarchy process (AHP). 4-Pyridoxic acid (4-PA), cotinine, trans-3'-hydroxycotinine (trans-3'-OH-Cot) and 1,4-methylimidazole acetic acid (MIAA) were selected as population biomarkers. The estimated model population showed the highest correlations (r2 = 0.97, p < 0.01) and lowest variation (one way-ANOVA, p = 0.82, mean variation: -0.1%) comparing to the census data, suggestion better population estimation. The estimated consumption of acesulfame, caffeine, paracetamol and amantadine was 6.7 ± 2.4 mg/day/inh, 50.5 ± 38.5 mg/day/inh, 61.5 ± 52.7 mg/day/inh and 0.52 ± 0.33 mg/day/inh, respectively. Meanwhile, the prevalence of paracetamol and amantadine was calculated to be 5.3% ± 4.5% and 0.28% ± 0.18%, respectively. The estimated results were consistent with that of previous researches in China and were also in accordance with the consumption calculated by sales data (acesulfame and paracetamol). Moreover, uncertainty study showed decrease in population-associated uncertainties by using a multi-parameter population model. The results demonstrated that the multi-parameter population model constructed in this research is feasible to apply in WBE and might lead to lower uncertainties in population estimation.


Assuntos
Cafeína , Águas Residuárias , Biomarcadores , China , Águas Residuárias/análise
9.
J Hazard Mater ; 406: 124727, 2021 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-33310336

RESUMO

Improving biomass enzymatic saccharification is effective for crop straw utilization, whereas phytoremediation is efficient for trace metal elimination from polluted agricultural soil. Here, we found that the green proteins extracted from Amaranthus leaf tissue could act as active biosurfactant to remarkably enhance lignocellulose enzymatic saccharification for high bioethanol production examined in eight grassy and woody plants after mild chemical and green-like pretreatments were performed. Notably, this study estimated that total green proteins supply collected from one-hectare-land Amaranth plants could even lead to additional 6400-12,400 tons of bioethanol, being over 10-fold bioethanol yield higher than those of soybean seed proteins and chemical surfactant. Meanwhile, the Amaranth green proteins were characterized as a dominated biosorbent for multiple trace metals (Cd, Pb, As) adsorption, being 2.9-6 folds higher than those of its lignocellulose. The Amaranth plants were also assessed to accumulate much more trace metals than all other plants as previously examined from large-scale contaminated soils. Furthermore, the Amaranth green proteins not only effectively block lignin to release active cellulases for the mostly enhanced biomass hydrolyzes, but also efficiently involve in multiple chemical bindings with Cd, which should thus address critical issues of high-costly biomass waste utilization and low-efficient trace metal remediation.


Assuntos
Amaranthus , Metais Pesados , Poluentes do Solo , Agricultura , Biodegradação Ambiental , Lignina , Metais Pesados/análise , Solo , Poluentes do Solo/análise
10.
Sci Total Environ ; 740: 139696, 2020 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-32927529

RESUMO

China has the world's largest burden of Hepatitis B virus (HBV) infection, with 86 million HBV carriers, including 32 million chronic Hepatitis B patients. To monitor the HBV prevalence in near real-time, a wastewater-based epidemiology (WBE) method by using lamivudine as a biomarker was conducted in 19 cities in the Southern part of China. LC-MS/MS was utilized to quantify lamivudine in sewage, and satisfactory method validation results were achieved. The average concentration of lamivudine in sewage was 156.4 ±â€¯107.1 ng/L, and the daily consumption was 30.1 ±â€¯19.8 mg/day/1000inh in average ranging from 0.4 to 105.5 mg/day/1000inh. The prevalence of chronic Hepatitis B was estimated to be 2.5% ±â€¯1.7% based on the prevalence of lamivudine usage, which was 0.035% ±â€¯0.023%. Besides, the estimated HBV prevalence in population aged over 15 years in 19 cities was 6.8% ±â€¯4.5% and was consistent with the previous statistical data of 7% in 2018. This research demonstrated that the estimation of HBV prevalence by WBE with lamivudine as a biomarker is feasible in big cities in Southern China.


Assuntos
Antivirais , Vírus da Hepatite B , Adolescente , China , Cromatografia Líquida , Cidades , Hepatite B , Vírus da Hepatite B/isolamento & purificação , Humanos , Prevalência , Espectrometria de Massas em Tandem , Vigilância Epidemiológica Baseada em Águas Residuárias
11.
Oncol Lett ; 19(2): 1235-1240, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32002027

RESUMO

Prognostic value of peritumoral fibrosis (PF) in pancreatic head cancer after resection was evaluated. A total of 143 pancreatic cancer patients who underwent tumor resection were enrolled. All patients underwent routine preoperative examination, including contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI). Patients receiving preoperative chemoradiation were excluded because it affects the proportion of fibrosis and cancer cells. Histopathological confirmation and classification of pancreatic head cancer (PHC) was made according to the standards of World Health Organization and the American Joint Committee on Cancer (AJCC). The presence of fibrosis was assessed histologically, and correlated with the clinicopathological characteristics and overall survival using univariate Kaplan-Meier analysis and a stepwise multivariable Cox regression model. Vein resection, resection margin, grading, nodal status, preoperative CA19-9 levels and PF were significantly associated with overall survival. Multivariate analysis showed that all the aforementioned were independent predictive factors of survival. In addition, the survival of patients with PF was significantly worse compared to those without (HR 1.392; P=0.027). Tumor necrosis is a valuable prognostic tool that can be included in the routine post-resection histopathological evaluation of pancreatic head cancer patients.

12.
J Exp Bot ; 71(10): 2956-2969, 2020 05 30.
Artigo em Inglês | MEDLINE | ID: mdl-32064495

RESUMO

UDP-glucose epimerases (UGEs) are essential enzymes for catalysing the conversion of UDP-glucose (UDP-Glc) into UDP-galactose (UDP-Gal). Although UDP-Gal has been well studied as the substrate for the biosynthesis of carbohydrates, glycolipids, and glycoproteins, much remains unknown about the biological function of UGEs in plants. In this study, we selected a novel rice fragile culm 24 (Osfc24) mutant and identified it as a nonsense mutation of the FC24/OsUGE2 gene. The Osfc24 mutant shows a brittleness phenotype with significantly altered cell wall composition and disrupted orientation of the cellulose microfibrils. We found significantly reduced accumulation of arabinogalactan proteins in the cell walls of the mutant, which may consequently affect plant growth and cell wall deposition, and be responsible for the altered cellulose microfibril orientation. The mutant exhibits dwarfism and paler leaves with significantly decreased contents of galactolipids and chlorophyll, resulting in defects in plant photosynthesis. Based on our results, we propose a model for how OsUGE2 participates in two distinct metabolic pathways to co-modulate cellulose biosynthesis and cell wall assembly by dynamically providing UDP-Gal and UDP-Glc substrates.


Assuntos
Oryza , UDPglucose 4-Epimerase , Parede Celular/metabolismo , Glucose/metabolismo , Oryza/genética , Oryza/metabolismo , Fotossíntese , UDPglucose 4-Epimerase/genética , UDPglucose 4-Epimerase/metabolismo , Difosfato de Uridina/metabolismo
13.
Talanta ; 208: 120452, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31816737

RESUMO

Plant cell walls represent enormous biomass resources for biofuels, and it thus becomes important to establish a sensitive and wide-applicable approach to visualize wall polymer distribution and destruction during plant growth and biomass process. Despite quantum dots (QDs) have been applied to label biological specimens, little is reported about its application in plant cell walls. Here, semiconductor QDs (CdSe/ZnS) were employed to label the secondary antibody directed to the epitopes of pectin or xylan, and sorted out the optimal conditions for visualizing two polysaccharides distribution in cell walls of rice stem. Meanwhile, the established QDs approach could simultaneously highlight wall polysaccharides and lignin co-localization in different cell types. Notably, this work demonstrated that the QDs labeling was sensitive to profile distinctive wall polymer destruction between alkali and acid pretreatments with stem tissues of rice. Hence, this study has provided a powerful tool to characterize wall polymer functions in plant growth and development in vivo, as well as their distinct roles during biomass process in vitro.


Assuntos
Compostos de Cádmio , Parede Celular/química , Oryza , Pectinas/análise , Pontos Quânticos , Compostos de Selênio , Sulfetos , Xilanos/análise , Compostos de Zinco , Epitopos/análise , Células Vegetais/química , Caules de Planta/química
14.
Neurosci Biobehav Rev ; 110: 150-173, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31101438

RESUMO

The synthetic cathinones are derived from the naturally occurring drug cathinone found in the khat plant (Catha edulis) and have chemical structures and neurochemical consequences similar to other psychostimulants. This class of new psychoactive substances (NPS) also has potential for use and abuse coupled with a range of possible adverse effects including neurotoxicity and lethality. This review provides a general background of the synthetic cathinones in terms of the motivation for and patterns and demographics of their use as well as the behavioral and physiological effects that led to their spread as abused substances and consequent regulatory control. This background is followed by a review focusing on their rewarding and aversive effects as assessed in various pre-clinical animal models and the contribution of these effects to their self-administration (implicating their use and abuse potential). The review closes with an overview of the consequences of synthetic cathinone use and abuse in terms of their potential to produce neurotoxicity and lethality. These characterizations are discussed in the context of other classical psychostimulants.


Assuntos
Alcaloides , Estimulantes do Sistema Nervoso Central , Psicotrópicos/farmacologia , Transtornos Relacionados ao Uso de Substâncias/tratamento farmacológico , Alcaloides/efeitos adversos , Alcaloides/farmacologia , Animais , Estimulantes do Sistema Nervoso Central/efeitos adversos , Estimulantes do Sistema Nervoso Central/farmacologia , Humanos , Metanfetamina/efeitos adversos , Metanfetamina/farmacologia , Psicotrópicos/efeitos adversos , Autoadministração
15.
Int J Mol Sci ; 20(20)2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31600873

RESUMO

Grain size and weight are two important determinants of grain yield in rice. Although overexpression of sucrose synthase (SUS) genes has led to several improvements on cellulose and starch-based traits in transgenic crops, little is reported about SUS enhancement of hull size and grain weight in rice. In this study, we selected transgenic rice plants that overexpressed OsSUS1-6 genes driven with the maize Ubi promoter. Compared to the controls (wild type and empty vector line), all independent OsSUS homozygous transgenic lines exhibited considerably increased grain yield and grain weights. Using the representative OsSUS3 overexpressed transgenic plants, four independent homozygous lines showed much raised cell numbers for larger hull sizes, consistent with their enhanced primary cell wall cellulose biosynthesis and postponed secondary wall synthesis. Accordingly, the OsSUS3 transgenic lines contained much larger endosperm volume and higher starch levels than those of the controls in the mature grains, leading to increased brown grain weights by 15-19%. Hence, the results have demonstrated that OsSUS overexpression could significantly improve hull size and grain weight by dynamically regulating cell division and starch accumulation in the transgenic rice.


Assuntos
Divisão Celular/genética , Grão Comestível , Glucosiltransferases/metabolismo , Oryza/genética , Oryza/metabolismo , Amido/metabolismo , Celulose/biossíntese , Endosperma/genética , Endosperma/metabolismo , Regulação da Expressão Gênica de Plantas , Família Multigênica , Oryza/classificação , Fenótipo , Filogenia , Plantas Geneticamente Modificadas
16.
J Vis Exp ; (144)2019 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-30829319

RESUMO

Miniaturized spacecraft and satellites require smart, highly efficient and durable low-thrust thrusters, capable of extended, reliable operation without attendance and adjustment. Thermochemical thrusters which utilize thermodynamic properties of gases as a means of acceleration have physical limitations on their exhaust gas velocity, resulting in low efficiency. Moreover, these engines demonstrate extremely low efficiency at small thrusts and may be unsuitable for continuously operating systems which provide real-time adaptive control of the spacecraft orientation, velocity and position. In contrast, electric propulsion systems which use electromagnetic fields to accelerate ionized gases (i.e., plasmas) do not have any physical limitation in terms of exhaust velocity, allowing virtually any mass efficiency and specific impulse. Low-thrust Hall thrusters have a lifetime of several thousand hours. Their discharge voltage ranges between 100 and 300 V, operating at a nominal power of <1 kW. They vary from 20 to 100 mm in size. Large Hall thrusters can provide fractions of millinewton of thrust. Over the past few decades, there has been an increasing interest in small mass, low power, and high efficiency propulsion systems to drive satellites of 50-200 kg. In this work, we will demonstrate how to build, test, and optimize a small (30 mm) Hall thruster capable of propelling a small satellite weighing about 50 kg. We will show the thruster operating in a large space environment simulator, and describe how thrust is measured and electric parameters, including plasma characteristics, are collected and processed to assess key thruster parameters. We will also demonstrate how the thruster is optimized to make it one of the most efficient small thrusters ever built. We will also address challenges and opportunities presented by new thruster materials.


Assuntos
Miniaturização/instrumentação , Astronave/instrumentação , Aceleração , Desenho de Equipamento , Gases/química , Temperatura , Emissões de Veículos
17.
J Nanosci Nanotechnol ; 19(6): 3519-3527, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-30744780

RESUMO

Molybdenum disulfide (MoS2), as a typical layered transition metal sulfide, has been widely used in photocatalysis. Here, we report layered MoS2 nanosheet-coated TiO2 heterostructures that were prepared using a simple photo-assisted deposition method. The as-prepared samples were investigated in detail by using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. Results demonstrated that the MoS2 nanosheets uniformly covered the outer surface of TiO2. The visible light-sensitive photocatalytic activity was evaluated by the removal of methylene blue (MB) and 2-chlorophenol (2-CP) in aqueous solution. Thus, the MoS2/TiO2 heterostructures exhibited improved photocatalytic degradation activity under visible light compared with the pure TiO2. Under visible light irradiation for 90 min, the degradation efficiencies of MB and 2-CP over the MoS2/TiO2 sample (sunlight irradiation time: 30 min) are as high as 93.6% and 70.6%, respectively. Furthermore, the corresponding mechanism of enhanced photocatalytic activity is proposed on the basis of the comprehensively investigated results from the radical trapping experiments, photoluminescence spectroscopy, and electron spin resonance analysis. The hole oxidation, hydroxyl radicals, and superoxide anion radicals act as the active species simultaneously in the photodegradation of the dye molecules. However, of these species, hole oxidation played the most important roles in the photocatalytic reaction.

18.
Neurotox Res ; 35(4): 993-998, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30806983

RESUMO

25C-NBOMe is a designer substituted phenethylamine and a high-potency psychedelic that acts on the 5-HT2A receptor. Although 25C-NBOMe overdoses have been related to several deaths in the USA and Europe, very limited data exists on the in vitro neurotoxicity of 25C-NBOMe. In this study, we found that 25C-NBOMe potently reduced cell viability of SH-SY5Y, PC12, and SN4741 cells, with IC50 values of 89, 78, and 62 µM, respectively. Methamphetamine decreased the cell viability of these cells with IC50 values at millimolar range in the same tests, indicating that 25C-NBOMe is > 50 times more potent than methamphetamine in its ability to reduce viability of SH-SY5Y cells. The neurotoxicity of 25C-NBOMe on SH-SY5Y cells was further confirmed by using fluorescein diacetate/propidium iodide double staining. 25C-NBOMe elevated the expression of phosphorylated extracellular signal-regulated kinase (pERK), but decreased the expression of phosphorylated Akt and phosphorylated Ser9- glycogen synthase kinase 3ß (GSK3ß) in time- and concentration-dependent manners. Interestingly, either specific GSK3ß inhibitors or specific mitogen-activated protein kinase kinase (MEK) inhibitors significantly prevented 25C-NBOMe-induced neurotoxicity in SH-SY5Y cells. These results suggest that 25C-NBOMe unexpectedly produced more potent neurotoxicity than methamphetamine and that the inhibition of the Akt pathway and activation of the ERK cascade might be involved in 25C-NBOMe-induced neurotoxicity. Most importantly, these findings further inform the toxicity of 25C-NBOMe abuse to the central nervous system for public health.


Assuntos
Benzilaminas/toxicidade , Drogas Desenhadas/toxicidade , Alucinógenos/toxicidade , Metanfetamina/toxicidade , Neurônios/efeitos dos fármacos , Fenetilaminas/toxicidade , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Humanos , Concentração Inibidora 50 , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Camundongos , Neurônios/metabolismo , Células PC12 , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos
19.
Biotechnol Biofuels ; 12: 11, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30636971

RESUMO

Background: Genetic modification of plant cell walls has been implemented to reduce lignocellulosic recalcitrance for biofuel production. Plant glycoside hydrolase family 9 (GH9) comprises endo-ß-1,4-glucanase in plants. Few studies have examined the roles of GH9 in cell wall modification. In this study, we independently overexpressed two genes from GH9B subclasses (OsGH9B1 and OsGH9B3) and examined cell wall features and biomass saccharification in transgenic rice plants. Results: Compared with the wild type (WT, Nipponbare), the OsGH9B1 and OsGH9B3 transgenic rice plants, respectively, contained much higher OsGH9B1 and OsGH9B3 protein levels and both proteins were observed in situ with nonspecific distribution in the plant cells. The transgenic lines exhibited significantly increased cellulase activity in vitro than the WT. The OsGH9B1 and OsGH9B3 transgenic plants showed a slight alteration in three wall polymer compositions (cellulose, hemicelluloses, and lignin), in their stem mechanical strength and biomass yield, but were significantly decreased in the cellulose degree of polymerization (DP) and lignocellulose crystalline index (CrI) by 21-22%. Notably, the crude cellulose substrates of the transgenic lines were more efficiently digested by cellobiohydrolase (CBHI) than those of the WT, indicating the significantly increased amounts of reducing ends of ß-1,4-glucans in cellulose microfibrils. Finally, the engineered lines generated high sugar yields after mild alkali pretreatments and subsequent enzymatic hydrolysis, resulting in the high bioethanol yields obtained at 22.5% of dry matter. Conclusions: Overproduction of OsGH9B1/B3 enzymes should have specific activity in the postmodification of cellulose microfibrils. The increased reducing ends of ß-1,4-glucan chains for reduced cellulose DP and CrI positively affected biomass enzymatic saccharification. Our results demonstrate a potential strategy for genetic modification of cellulose microfibrils in bioenergy crops.

20.
Carbohydr Polym ; 192: 273-281, 2018 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-29691021

RESUMO

Miscanthus is a leading bioenergy crop and rice provides enormous biomass for biofuels. Using Calcofluor White staining, this work in situ observed an initial lignocellulose hydrolysis in two distinct Miscanthus accessions, rice cultivar (NPB), and Osfc16 mutant after mild chemical pretreatments. In comparison, the M. sin and Osfc16 respectively exhibited weak Calcofluor fluorescence compared to the M. sac and NPB during enzymatic hydrolysis, consistent with the high biomass saccharification detected in vitro. Using xyloglucan-directed monoclonal antibodies (mAbs), xyloglucan deconstruction was observed from initial cellulose hydrolysis, whereas the M. sin and Osfc16 exhibited relatively strong immunolabeling using xylan-directed mAb, confirming previous findings of xylan positive impacts on biomass saccharification. Furthermore, the M. sin showed quick disappearance of RG-I immunolabeling with varied HG labelings between acid and alkali pretreatments. Hence, this study demonstrated a quick approach to explore wall polymer distinct deconstruction for enhanced biomass saccharification under chemical pretreatment in bioenergy crops.


Assuntos
Biomassa , Biopolímeros/metabolismo , Parede Celular/metabolismo , Oryza/citologia , Oryza/efeitos dos fármacos , Poaceae/citologia , Poaceae/efeitos dos fármacos , Metabolismo dos Carboidratos/efeitos dos fármacos , Parede Celular/efeitos dos fármacos , Celulose/metabolismo , Concentração de Íons de Hidrogênio , Hidrólise/efeitos dos fármacos , Hidróxidos/farmacologia , Oryza/metabolismo , Poaceae/metabolismo , Compostos de Potássio/farmacologia
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