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1.
Polymers (Basel) ; 14(10)2022 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-35631917

RESUMO

The influence of textile wastewater (TWW) secondary effluent on ultrafiltration (UF) membrane characteristics was investigated. TWW treated with a membrane bioreactor was subjected to four commercial UF membranes (2, 3, 5, and 10 kDa). Both the pristine membranes and the membranes after TWW secondary effluent treatment were characterized. Surface roughness, microscopic analysis of the membrane surface and cross-section, zeta potential, contact angle, membrane composition, and membrane flux were compared. After treatment of secondary effluent, the zeta potential decreased for 5 and 10 kDa membranes, while the contact angle and surface roughness increased for all investigated membranes. In addition, a fouling layer formed on all membranes, and new interactions with pollutants and membranes were confirmed. Membranes with larger pores (5 and 10 kDa) showed a greater decrease in permeate flux during treatment. Detailed analysis showed variations in membrane characteristics after TWW secondary effluent treatment, indicating the stability of the membranes used.

2.
Appl Spectrosc ; 76(7): 823-830, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35255731

RESUMO

Fourier transform infrared spectroscopy was performed for two structurally similar liquid crystals: 4-octyloxybenzoic acid and 4-decyloxybenzoic acid in 6-15 THz range. Density functional theory modeling at PBE0/def2-TZVPP level was used to assign the vibrational modes to each observed absorption peak. We observed six peaks that are common for both liquid crystals, assigned to the same vibrational modes and appearing at similar energies. Each of the samples also had additional peaks unique to itself. A strong absorption peak appears at about 280 cm-1 for both samples; however, it corresponds to different vibrational modes for the two samples. This work shows that the spectroscopy in this often-neglected frequency range can easily distinguish structurally similar compounds.

3.
Appl Spectrosc ; 76(3): 300-309, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35109695

RESUMO

Terra preta is a fertile anthropogenic soil found in the Amazon basin. One of the most significant differences between the terra preta and surrounding soils is that terra preta is rich in aromatic carbons. Previous infrared investigations of terra preta were reported at energies above 1000 cm-1 where many other forms of carbon also have absorption lines. No measurements have been reported below 800 cm-1, where many absorptions associated with aromatic carbons occur in the absence of aliphatic carbon lines. We employ Fourier transform infrared spectroscopy between 150 cm-1 and 500 cm-1. A comparison was made between the spectra of terra preta, several pure aromatic compounds, organic fertilizers developed to replicate terra preta and several Australian soils, some of which containing char from bushfires. The spectra in the 150-500 cm-1 range were very similar between terra preta and the organic fertilizers, while they were very different for the natural soils. These findings indicate that the content of aromatic carbons in terra preta and organic fertilizers is different than in natural soils containing the bushfire chars, but also soils produced entirely by bacterial and fungal activities. This point to the importance of the preparation conditions of the biochars, which are essential ingredients of terra preta and organic fertilizers used in this study.


Assuntos
Carbono , Solo , Austrália , Solo/química , Espectroscopia de Infravermelho com Transformada de Fourier
4.
Mater Sci Eng C Mater Biol Appl ; 123: 111970, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33812598

RESUMO

Nanoparticles have a great potential to increase the therapeutic efficiency of several cancer therapies. This research examines the potential for silver-doped lanthanum manganite nanoparticles to enhance radiation therapy to target radioresistant brain cancer cells, and their potential in combinational therapy with magnetic hyperthermia. Magnetic and structural characterisation found all dopings of nanoparticles (NPs) to be pure and single phase with an average crystallite size of approximately 15 nm for undoped NPs and 20 nm for silver doped NPs. Additionally, neutron diffraction reveals that La0.9Ag0.1MnO3 (10%-LAGMO) NPs exhibit residual ferromagnetism at 300 K that is not present in lower doped NPs studied in this work, indicating that the Curie temperature may be manipulated according to silver doping. This radiobiological study reveals a completely cancer-cell selective treatment for LaMnO3, La0.975Ag0.025MnO3 and La0.95Ag0.05MnO3 (0, 2.5 and 5%-LAGMO) and also uncovers a potent combination of undoped lanthanum manganite with orthovoltage radiation. Cell viability assays and real time imaging results indicated that a concentration of 50 µg/mL of the aforementioned nanoparticles do not affect the growth of Madin-Darby Canine Kidney (MDCK) non-cancerous cells over time, but stimulate its metabolism for overgrowth, while being highly toxic to 9L gliosarcoma (9LGS). This is not the case for 10%-LAGMO nanoparticles, which were toxic to both non-cancerous and cancer cell lines. The nanoparticles also exhibited a level of toxicity that was regulated by the overproduction of free radicals, such as reactive oxygen species, amplified when silver ions are involved. With the aid of fluorescent imaging, the drastic effects of these reactive oxygen species were visualised, where nucleus cleavage (an apoptotic indicator) was identified as a major consequence. The genotoxic response of this effect for 9LGS and MDCK due to 10%-LAGMO NPs indicates that it is also causing DNA double strand breaks within the cell nucleus. Using 125 kVp orthovoltage radiation, in combination with an appropriate amount of NP-induced cell death, identified undoped lanthanum manganite as the most ideal treatment. Real-time imaging following the combination treatment of undoped lanthanum manganite nanoparticles and radiation, highlighted a hinderance of growth for 9LGS, while MDCK growth was boosted. The clonogenic assay following incubation with undoped lanthanum manganite nanoparticles combined with a relatively low dose of radiation (2 Gy) decreased the surviving fraction to an exceptionally low (0.6 ± 6.7)%. To our knowledge, these results present the first biological in-depth analysis on silver-doped lanthanum manganite as a brain cancer selective chemotherapeutic and radiation dose enhancer and as a result will propel its first in vivo investigation.


Assuntos
Nanopartículas Metálicas , Prata , Animais , Cães , Lantânio/toxicidade , Compostos de Manganês , Nanopartículas Metálicas/toxicidade
5.
Appl Spectrosc ; 69(5): 590-6, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25909770

RESUMO

Terahertz spectroscopy of benzoic acid (BA) and two of its derivatives, 2-hydroxybenzoic acid (2OH-BA) and 3-hydroxybenzoic acid (3OH-BA), has been investigated in the spectral region 200 to 500 cm(-1) (6.06 to 15.15 THz). The spectra show distinct absorption features. There is agreement between some of the absorption lines observed for these compounds, despite a shift in energy, which is attributed to the differences in the molecular structures. Numerical modeling gave corresponding absorption lines, and this helped in the assignment. Temperature dependence studies revealed that most of the absorption lines are composite lines in this frequency region.

6.
Inorg Chem ; 52(6): 2817-22, 2013 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-23461562

RESUMO

Manganese-based layered coordination polymer ([Mn(tfbdc)(4,4'-bpy)(H2O)2], Mn-LCP) with microporous structure was synthesized by reaction of 2,3,5,6-tetrafluoroterephthalatic acid(H2tfbdc) and 4,4'-bipyridine(4,4'-bpy) with manganese(II) acetate tetrahydrate in water solution. Mn-LCP was characterized by elemental analysis, IR spectra, thermogravimetric analysis, X-ray single-crystal structure analysis, and powder X-ray diffraction. Magnetic susceptibility data from 300 to 1.8K show that there is a weak antiferromagnetic exchange between Mn(II) ions in Mn-LCP. As anode material, the Mn-LCP electrode exhibits an irreversible high capacity in the first discharge process and a reversible lithium storage capacity of up to about 390 mA h/g from the fourth cycle. It might provide a new method for finding new electrode materials in lithium-ion batteries.

7.
Chemistry ; 18(2): 488-97, 2012 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-22147554

RESUMO

Polyhedral magnetite nanocrystals with multiple facets were synthesised by a low temperature hydrothermal method. Atomistic simulation and calculations on surface attachment energy successfully predicted the polyhedral structure of magnetite nanocrystals with multiple facets. X-ray diffraction, field emission scanning electron microscopy, and high resolution transmission microscopy confirmed the crystal structure of magnetite, which is consistent with the theoretical modelling. The magnetic property measurements show the superspin glass state of the polyhedral nanocrystals, which could originate from the nanometer size of individual single crystals. When applied as an anode material in lithium ion cells, magnetite nanocrystals demonstrated an outstanding electrochemical performance with a high lithium storage capacity, a satisfactory cyclability, and an excellent high rate capacity.


Assuntos
Óxido Ferroso-Férrico/química , Lítio/química , Imãs/química , Nanopartículas/química , Temperatura Baixa , Fontes de Energia Elétrica , Óxido Ferroso-Férrico/síntese química , Nanopartículas/ultraestrutura , Difração de Raios X
8.
Chemistry ; 16(36): 11020-7, 2010 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-20690118

RESUMO

Highly ordered mesoporous Co(3)O(4) nanostructures were prepared using KIT-6 and SBA-15 silica as hard templates. The structures were confirmed by small angle X-ray diffraction, high resolution transmission electron microscopy, and N(2) adsorption-desorption isotherm analysis. Both KIT-6 cubic and SBA-15 hexagonal mesoporous Co(3)O(4) samples exhibited a low Néel temperature and bulk antiferromagnetic coupling due to geometric confinement of antiferromagnetic order within the nanoparticles. Mesoporous Co(3)O(4) electrode materials have demonstrated the high lithium storage capacity of more than 1200 mAh g(-1) with an excellent cycle life. They also exhibited a high specific capacitance of 370 F g(-1) as electrodes in supercapacitors.

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