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1.
J Nanosci Nanotechnol ; 20(2): 789-801, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31383074

RESUMO

Magnetic Ni0.5Cu0.5Fe2O4/SiO2 nanocomposites were prepared via a solution combustion process, and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), Energy dispersive X-ray Spectroscopy (EDX) and vibrating sample magnetometer (VSM). The magnetic Ni0.5Cu0.5Fe2O4/SiO2 nanocomposites were employed to remove Congo red (CR) from aqueous solution, and the adsorption process was optimized by response surface methodology (RSM). The optimum conditions were the silica content of 12.6 wt%, the calcination temperature of 501 °C and the pH value of 7.13. The adsorption kinetics and the adsorption isotherm of CR onto magnetic Ni0.5Cu0.5Fe2O4/SiO2 nanocomposites at room temperature were investigated, and the intraparticle diffusion kinetics model and Redlich-Peterson isotherm model fitted well the respective process.

2.
Environ Int ; 130: 104922, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31226557

RESUMO

Diesel emissions from freight transportation activities are a key threat to public health. This study examined the air quality and public health impacts of projected freight-related emissions in 2050 over the continental United States. Three emission scenarios were considered: (1) a projected business-as-usual socioeconomic growth with freight fleet turnover and stringent emission control (CTR); (2) the application of a carbon pricing climate policy (PO); and (3) further technology improvements to eliminate high-emitting conditions in the truck fleet (NS). The PO and NS cases are superimposed on the CTR case. Using a WRF-SMOKE-CMAQ-BenMAP modeling framework, we quantified the impacts of diesel fine particulate matter (PM2.5) emissions change on air quality, health, and economic benefits. In the CTR case, we simulate a widespread reduction of PM2.5 concentrations, between 0.5 and 1.5 µg m-3, comparing to a base year of 2011. This translates into health benefits of 3600 (95% CI: 2400-4800) prevented premature deaths, corresponding to $38 (95% CI: $3.5-$100) billion. Compared to CTR case, the PO case can obtain ~9% more health benefits nationally, however, climate policy also affects the health outcomes regionally due to transition of demand from truck to rail; regions with fewer trucks could gain in health benefits, while regions with added rail freight may potentially experience a loss in health benefits due to air quality degradation. The NS case provides substantial additional benefits (~20%). These results support that a combination of continuous adoption of stringent emission standards and strong improvements in vehicle technology are necessary, as well as rewarding, to meet the sustainable freight and community health goals. States and metropolitan areas with high population density and usually high freight demand and emissions can take more immediate actions, such as accelerating vehicle technology improvements and removing high-emitting trucks, to improve air quality and health benefits.

3.
Appl Opt ; 58(9): 2183-2189, 2019 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-31044916

RESUMO

Traditional microscopes do not meet a wide field of view and high resolution at the same time. We propose a method for image restoration and color fusion of digital microscopes. It combines a single high-resolution gray scale hologram with a low-resolution color image to obtain a high-resolution color image. Specifically, the high-resolution gray scale image is obtained by reconstructing three different height holograms using a wavelet-based method, and the color information is obtained using a portable cell phone microscope. The subsequent calibration and blending of colors ultimately results in a high-resolution, wide-field color map that can be of great help in the study of pathology or biomedicine. This method breaks the rule that the large field of view and high resolution of a traditional microscope cannot be simultaneously satisfied, which can realize a more comprehensive observation of the shape and details of the slice.

4.
J Nanosci Nanotechnol ; 19(9): 5790-5795, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-30961740

RESUMO

A facile solution combustion and gel calcination process for the preparation of magnetic MnFe²O4 nanoparticles was introduced. The experimental results showed that the volume of absolute alcohol and the calcination temperature were two key factors to grain size, crystallinity and magnetic properties of MnFe²O4 nanoparticles. With the volume of absolute alcohol increasing from 15 to 100 mL, the average grain size of MnFe²O4 nanoparticles calcined at 400 °C for 2 h increased from 13.4 nm to 36.0 nm, and the saturation magnetization (Ms) value of MnFe²O4 nanoparticles increased from 1.2 emu/g to 105.5 emu/g; while, with the calcination temperature increasing from 400 °C to 800 °C, the average grain size increased from 13.4 nm to 32.9 nm, and the saturation magnetization value increased from 1.2 emu/g to 15.3 emu/g. The specific surface area of MnFe²O4 nanoparticles calcined at 400 °C for 2 h with absolute alcohol of 30 mL was measured, which was large of 49.6 m²/g.

5.
Sci Total Environ ; 613-614: 820-828, 2018 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-28942315

RESUMO

This study investigates a significant biomass burning (BB) event occurred in Colorado of the United States in 2012 using the Community Multi-scale Air Quality (CMAQ) model. The simulation reasonably reproduced the significantly high upper tropospheric O3 concentrations (up to 145ppb) caused by BB emissions. We find the BB-induced O3 was primarily affected by chemical reactions and dispersion during its transport. In the early period of transport, high NOx and VOCs emissions caused O3 production due to reactions with the peroxide and hydroxyl radicals, HO2 and OH. Here, NOx played a key role in O3 formation in the BB plume. The results indicated that HO2 in the BB plume primarily came from formaldehyde (HCHO+hv=2HO2+CO), a secondary alkoxy radical (ROR=HO2). CO played an important role in the production of recycled HO2 (OH+CO=HO2) because of its abundance in the BB plume. The chemically produced HO2 was largely converted to OH by the reactions with NO (HO2+NO=OH+NO2) from BB emissions. This is in contrast to the surface, where HO2 and OH are strongly affected by VOC and HONO, respectively. In the late stages of transport, the O3 concentration was primarily controlled by dispersion. It stayed longer in the upper troposphere compared to the surface due to sustained depletion of NOx. Sensitivity analysis results support that O3 in the BB plume is significantly more sensitive to NOx than VOCs.

6.
Nat Prod Res ; 31(21): 2537-2543, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28503945

RESUMO

One new ribonucleotide, 5'-(3''-deoxy-ß-D-ribofuranosyl)-3'-deoxyadenosine (1), and 14 known compounds (2-15) were isolated from an ethanol extract of Cordyceps militaris. The chemical structures of these compounds were determined from 1D and 2D NMR (1H-1H COSY, HMBC, HMQC and NOESY) and HR-ESI-MS spectra, and results were compared with data from the literature. The effects of all isolated compounds were measured on NF-κB activation, with compound 2 exhibiting significant inhibitory activity against TNF-α-induced NF-κB reporter gene expression in HeLa cells from 3 to 100 µM.


Assuntos
Cordyceps/química , NF-kappa B/genética , Ribonucleotídeos/química , Ribonucleotídeos/farmacologia , Avaliação Pré-Clínica de Medicamentos/métodos , Etanol/química , Células HeLa , Humanos , Espectroscopia de Ressonância Magnética , Estrutura Molecular , NF-kappa B/metabolismo , Ribonucleotídeos/isolamento & purificação , Espectrometria de Massas por Ionização por Electrospray , Fator de Necrose Tumoral alfa/farmacologia
7.
Org Lett ; 14(24): 6254-7, 2012 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-23215443

RESUMO

Inherently chiral tetraoxacalix[2]arene[2]pyridines containing C(2) symmetry were synthesized efficiently from a macrocyclic condensation reaction of resorcinol derivatives with 2,6-dichloro-3-nitropyridine in a one-pot reaction manner, while tetraoxacalix[2]arene[2]pyridine with an ABCD-substitution pattern was prepared in a good yield by means of a stepwise fragment coupling approach. Postmacrocyclization chemical manipulations led to functionalized tetraoxacalix[2]arene[2]pyridines. A racemic sample was resolved into enantiopure (+)- and (-)-inherently chiral compounds.


Assuntos
Calixarenos/síntese química , Piridinas/síntese química , Resorcinóis/química , Calixarenos/química , Cristalografia por Raios X , Estrutura Molecular , Piridinas/química , Estereoisomerismo
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