Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 10 de 10
Filtrar
Más filtros










Intervalo de año de publicación
1.
Nanotechnology ; 35(26)2024 Apr 09.
Artículo en Inglés | MEDLINE | ID: mdl-38527359

RESUMEN

A novel, rapid, and facile method for one-step sonoelectrochemical synthesis of zinc oxide nanoparticles (UEZ) was introduced in this study. The optimum operating parameters have been selected at a voltage of 7.5 V, KCl concentration of 0.5 M, and the reaction time of 60 min. The as-prepared UEZ were characterized by XRD, SEM, and HRTEM. It was found that the UEZ has a hexagonal wurtzite structure with high crystalline quality, good purity, a size range of 30-100 nm, and good photocatalytic degradation of methylene blue. This work provides a facile route for large-scale synthesizing ZnO nanoparticles via anodization.

2.
RSC Adv ; 13(16): 11171-11181, 2023 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-37056971

RESUMEN

In this work, a new facile one-spot method has been designed to fabricate a magnetic recyclable Fe3O4/rice husk biochar photocatalyst (FBP) for the removal of Ciprofloxacin (CIP) in aqueous solution. This method combines ultrasonic-assisted impregnation and precipitation, which can overcome the difficulties of long-time reactions, complex procedures, and extreme condition requirements. The successful fabrication of the Fe3O4/biochar material has been proven by a series of material characterization techniques, including X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Raman, Fourier Transform Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS), and vibrating sample magnetometer (VSM). Moreover, the as-product FBP exhibited the excellent ability of photodegrading CIP and the possibility of magnetic recovery from the aqueous solution, suggesting a potential solution for removing antibiotic pollutants in environmental remediation.

3.
RSC Adv ; 13(11): 7372-7379, 2023 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-36895775

RESUMEN

A novel facile combination of precipitation and plasma discharge reaction is successfully employed for one-step synthesis of an α-Fe2O3-Fe3O4 graphene nanocomposite (GFs). The co-existence and anchoring of hematite (α-Fe2O3) and magnetite (Fe3O4) nanoparticles onto a graphene sheet in the as synthesized GFs were verified by results of XRD, Raman, SEM, TEM, and XPS. HRTEM characterization was used for confirming the bonding between α-Fe2O3/Fe3O4 nanoparticles and the graphene sheet. Consequently, GFs shows superior photodegrading performance towards methylene blue (MB), compared to individual α-Fe2O3/Fe3O4 nanoparticles, as a result of band gap narrowing and the electron-hole pair recombination rate reducing. Moreover, GFs allows a good possibility of separating and recycling under an external-magnetic field, suggesting potential in visible-light-promoted photocatalytic applications.

4.
R Soc Open Sci ; 10(2): 220819, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36778963

RESUMEN

A green synthetic approach to synthesize silver nanoparticles (AgNPs) using the stem extract of Piper chaudocanum for highly sensitive colorimetric detection of Hg2+ with a low limit of detection of 23 nM and easy colorimetric read-out has been reported. In addition, the biosynthesized AgNPs demonstrated efficient antibacterial activity against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. The morphology and structure of the as-synthesized AgNPs were examined using SEM, TEM, EDX, XRD and FT-IR analyses. The XRD and TEM results confirm the formation of AgNPs with an average particle size of 8-12 nm. The TLC, CC and HPLC revealed that four main compounds, pentacosanoic acid (1), piperine (2), ß-sitosterol (3), and campesterol glucoside (4), isolated from P. chaudocanum extract act as reducing and stabilizing agents for AgNP formation, and piperine plays a vital role in green synthesis. The chemical structures of these compounds were determined by ESI MS, FTIR, and one- and two-dimensional NMR spectroscopic data analysis. This approach is an efficient, green, cost-effective, eco-friendly and promising technique for synthesizing AgNPs with applications in the colorimetric detection of Hg2+ and antibacterial activity.

5.
RSC Adv ; 12(17): 10608-10618, 2022 Mar 31.
Artículo en Inglés | MEDLINE | ID: mdl-35425023

RESUMEN

In this study, we provide a simple and green approach to recycle waste zinc carbon batteries for making carbon dots and porous carbon material. The carbon dots are easily synthesized by one green step, the hydrothermal treatment of a carbon rod in a mixture of DI water and pure ethanol to obtain a blue fluorescence under UV light, which can be used directly as a fluorescence ink. The as-prepared carbon dot process give typical dots with a uniform diameter from 3 to 8 nm with a strong slight blue fluorescent. The porous carbon material is also recycled from carbon powder in a waste battery via one green step annealing process without any chemical activation and with a hierarchically porous structure. This porous carbon material is demonstrated as an electrode for symmetrical solid state supercapacitors (SSCs) in a sandwich structure: porous carbon/PVA-KOH/porous carbon. The SSCs using recycled porous carbon electrodes exhibit a good energy density of 4.58 W h kg-1 at a power density of 375 W kg-1 and 97.6% retention after 2000 cycles. The facile one green step of hydrothermal and also that of calcination provide a promising strategy to recycle waste zinc carbon batteries, which transfers the excellent applications.

6.
Nanotechnology ; 32(46)2021 Aug 25.
Artículo en Inglés | MEDLINE | ID: mdl-34359057

RESUMEN

In this study, we report a facile and effective approach for large-scale production of nitrogen-doped TiO2nanocrystals (UNTs) by a combination of ultrasonic irradiation and electrochemistry at room temperature using NH4NO3electrolyte as the nitrogen source. The as-prepared UNTs were then characterized by x-ray diffraction, Raman spectroscopy, x-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and UV-visible diffuse reflectance spectroscopy. The results indicated that the nitrogen content of UNTs reached 9.3% and bandgap energy of 2.62 eV, thus gave the high photocatalytic degradation of methylene blue under visible light irradiation. The mechanism for the formation of UNTs by ultrasonic-assisted electrochemical approach was also proposed.

7.
FEMS Microbiol Lett ; 368(16)2021 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-34415008

RESUMEN

Chitinases are enzymes that catalyze the degradation of chitin, a major component of the cell walls of pathogenic fungi and cuticles of insects, gaining increasing attention for the control of fungal pathogens and insect pests. Production of recombinant chitinase in a suitable host can result in a more pure product with less processing time and a significantly larger yield than that produced by native microorganisms. The present study aimed to express the synthetic chi42 gene (syncodChi42), which was optimized from the chi42 gene of Trichoderma asperellum SH16, in Escherichia coli to produce 42 kDa chitinase (Ta-CHI42); then determined the activity of this enzyme, characterizations and in vitro antifungal activity as well as its immunogenicity in mice. The results showed that Ta-CHI42 was overexpressed in E. coli. Analysis of the colloidal chitin hydrolytic activity of purified Ta-CHI42 on an agar plate revealed that this enzyme was in a highly active form. This is a neutral chitinase with pH stability in a range of 6-8 and has an optimum temperature of 45°C with thermal stability in a range of 25-35°C. The chitinolytic activity of Ta-CHI42 was almost completely abolished by 5 mM Zn2+ or 1% SDS, whereas it remained about haft under the effect of 1 M urea, 1% Triton X-100 or 5 mM Cu2+. Except for ions such as Mn2+ and Ca2+ at 5 mM that have enhanced chitinolytic activity; 5 mM of Na+, Fe2+ or Mg2+ ions or 1 mM EDTA negatively impacted the enzyme. Ta-CHI42 at 60 U/mL concentration strongly inhibited the growth of the pathogenic fungus Aspergillus niger. Analysis of western blot indicated that the polyclonal antibody against Ta-CHI42 was greatly produced in mice. It can be used to analyze the expression of the syncodChi42 gene in transgenic plants, through immunoblotting assays, for resistance to pathogenic fungi.


Asunto(s)
Quitinasas , Expresión Génica , Hypocreales , Animales , Quitina/metabolismo , Quitinasas/genética , Quitinasas/metabolismo , Escherichia coli/genética , Genes Sintéticos/genética , Hypocreales/enzimología , Hypocreales/genética , Ratones
8.
Nanotechnology ; 32(16): 16LT01, 2021 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-33455951

RESUMEN

In this study, oxygenated graphene nanosheets (OGNs) were successfully synthesized using a simple electrochemical exfoliation approach and applied to remove methylene blue (MB) in an aqueous solution. The surface morphology and structure of the OGNs were characterized by scanning electron microscopy, transmission electron microscopy, Raman, and x-ray photoelectron spectroscopy. The adsorption performance of OGNs towards aqueous MB was tested by batch experiments. Results showed that a large number of functional groups in OGNs enhanced the removal of MB from the aqueous solution due to the electrostatic interactions between the electrochemically oxygenated groups (e.g. C-OH, C-O, and C=O) and dye molecules. Using Langmuir adsorption isotherm, the maximum MB adsorption capacity (q max) was determined as high as 476.19 mg g-1. These results suggested that the as-prepared OGNs is an effective and promising adsorbent for removing MB, which could be studied extensively for color removal in wastewater treatment.

9.
Ultrason Sonochem ; 34: 978-983, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-27773329

RESUMEN

We present a novel and highly efficient method for exfoliating of graphite to produce graphene via the synergistic effects of in-situ plasma induced electrochemical exfoliation with ultrasonic energy, called ultrasonic-assisted cathodic electrochemical discharge. This method can work at moderate temperatures without the need of acidic media or expensive ionic electrolyte. The produced graphene exhibited a large lateral dimension of approximately 6µm and a thickness of 2.5nm, corresponding to approximately seven layers of graphene. An exfoliating mechanism of graphite to produce graphene sheets is also proposed in this study.

10.
Artículo en Vietnamita | WPRIM (Pacífico Occidental) | ID: wpr-2944

RESUMEN

Infant with high risk of Clifford syndrome was predicted by mean of amniotic fluid index (AFI) measurement before labor. There is reliability by underwent ultrasound evaluation for AFI measurement with modified four quadrant techniques before labor. 287 pregnant women were involved in this study. Authors found that: A high negative linear regression correlation between AFI and gestational age 38 to 42 weeks. After 38 weeks the AFI appeared to decline gradually the mean AFI was 144+/-40 in 38 weeks and 88+/-35 in 42 weeks of gestational age. There is a high relationship between Clifford syndrome and AFI. The cut-off point AFI <=40 as a predictor for predicting the fetal outcome related Clifford syndrome with the positive predictive value = 90. The negative predictive value: 98.2%. The specificity predictive value 99% and the positive predictive value: 64%.


Asunto(s)
Líquido Amniótico , Pronóstico , Síndrome
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...