Abstract:In this work, the effect of sodium citrate mixed with tobacco, in the presence and absence of SBA-15 material, was studied by thermogravimetric analysis coupled to Fourier-transform infrared spectrometry under N and air atmospheres. Depending on the atmosphere used, the decomposition of sodium citrate changes considerably at high temperatures, mainly due to the oxidation of the residue. The analysis of the experimental and calculated derivative thermogravimetric data of the sodium citrate/SBA-15 mixtures allow… Show more
“…The FTIR signals of CO 2 were observed at 2360 cm −1 and the peaks in ranges of 4000-3500 cm −1 and 1800-1300 cm −1 were from H 2 O. 22 Figure 4C shows the absorption intensities of FTIR peaks at 2360 cm −1 and 1698 cm −1 , which represented the contents of CO 2 and H 2 O, varied with temperature measured by TG-FTIR. The contents of both CO 2 and H 2 O increased with temperature at first and reached a maximum at about 680℃.…”
Section: Resultsmentioning
confidence: 98%
“…The crystallite size was calculated by Scherrer formula: where D is the average crystallite size, K is the Scherrer constant and its value is 0.89, γ is the X-ray wavelength, B is the full width at half maxima (FWHM) after removing the equipment broadening, and θ is the Bragg diffraction angle. 22 Figure 4C shows the absorption intensities of FTIR peaks at 2360 cm −1 and 1698 cm −1 , which represented the contents of CO 2 and H 2 O, varied with temperature measured by TG-FTIR. 20 TG-DSC combined with FTIR measurements of the amorphous products was used to investigate the formation mechanism of the hollow structure.…”
Hollow‐structured Al2O3 nanospheres were prepared by chemical vapor deposition (CVD) and further heat‐treatment process. For the CVD process, a unique cooling gas loop was designed in the precursor delivery system and amorphous Al2O3 nanospheres with incomplete pyrolysis intermediated products were obtained in a vertical fluidized bed at 500℃. The microstructure of the nanospheres tended to hollow after subsequent heat treatment at 1300℃ in air. It was found that the obtained Al2O3 hollow nanospheres showed a size of 100‐450 nm in diameter and 20‐80 nm in shell thickness. Transmission electron microscopy (TEM) and X‐ray diffraction (XRD) analysis confirmed that the Al2O3 hollow nanospheres were α‐Al2O3. The possible formation mechanism was proposed based on the results of the thermal gravimetric (TG) measurement connected with a Fourier transform infrared spectrometry (FTIR). The novel method to prepare Al2O3 hollow nanospheres can inspire ideas for the design and synthesis of other hollow‐structured nanospheres.
“…The FTIR signals of CO 2 were observed at 2360 cm −1 and the peaks in ranges of 4000-3500 cm −1 and 1800-1300 cm −1 were from H 2 O. 22 Figure 4C shows the absorption intensities of FTIR peaks at 2360 cm −1 and 1698 cm −1 , which represented the contents of CO 2 and H 2 O, varied with temperature measured by TG-FTIR. The contents of both CO 2 and H 2 O increased with temperature at first and reached a maximum at about 680℃.…”
Section: Resultsmentioning
confidence: 98%
“…The crystallite size was calculated by Scherrer formula: where D is the average crystallite size, K is the Scherrer constant and its value is 0.89, γ is the X-ray wavelength, B is the full width at half maxima (FWHM) after removing the equipment broadening, and θ is the Bragg diffraction angle. 22 Figure 4C shows the absorption intensities of FTIR peaks at 2360 cm −1 and 1698 cm −1 , which represented the contents of CO 2 and H 2 O, varied with temperature measured by TG-FTIR. 20 TG-DSC combined with FTIR measurements of the amorphous products was used to investigate the formation mechanism of the hollow structure.…”
Hollow‐structured Al2O3 nanospheres were prepared by chemical vapor deposition (CVD) and further heat‐treatment process. For the CVD process, a unique cooling gas loop was designed in the precursor delivery system and amorphous Al2O3 nanospheres with incomplete pyrolysis intermediated products were obtained in a vertical fluidized bed at 500℃. The microstructure of the nanospheres tended to hollow after subsequent heat treatment at 1300℃ in air. It was found that the obtained Al2O3 hollow nanospheres showed a size of 100‐450 nm in diameter and 20‐80 nm in shell thickness. Transmission electron microscopy (TEM) and X‐ray diffraction (XRD) analysis confirmed that the Al2O3 hollow nanospheres were α‐Al2O3. The possible formation mechanism was proposed based on the results of the thermal gravimetric (TG) measurement connected with a Fourier transform infrared spectrometry (FTIR). The novel method to prepare Al2O3 hollow nanospheres can inspire ideas for the design and synthesis of other hollow‐structured nanospheres.
“…46 The peak at 1610 cm −1 was attributed to (C=O) of the AgNPs-CIT ( Figure 3 ). 47 Figure 3 FT-IR spectra of silver nitrate (AgNO 3 ), AgNPs-CIT, and TSC. The black arrows represent the citrate area in TSC and AgNPs-CIT.…”
Section: Resultsmentioning
confidence: 99%
“…46 The peak at 1610 cm −1 was attributed to (C=O) of the AgNPs-CIT (Figure 3). 47 The Radical Scavenging Activity…”
Background
The nuclear factor kappa-B (NF-κB) is a major transcription factor responsible for the production of numerous inflammatory mediators, including the tumor necrosis factor (TNFα), which has a lethal association with cancer’s onset. The silver nanoparticles (AgNPs) are widely used in cancer treatment and several other biomedical applications.
Objective
The study aimed to determine the effects of silver citrate nanoparticles (AgNPs-CIT) on NF-κB activation together with TNFα mRNA/protein expressions in the phorbol myristate acetate (PMA)-stimulated MCF-7 human breast cancer cell-lines.
Methods
The AgNPs-CIT were synthesized by the reduction method, and the prepared AgNPs-CIT were characterized for their shape, absorption in UV-VIS electromagnetic radiations, size distribution, ζ-potential, and antioxidant activity. The MCF-7 cell-lines were pretreated with AgNPs-CIT and stimulated with PMA. The TNFα mRNA expressions were determined by real-time PCR, whereas the protein production was determined by the ELISA. The NF-κB activity was distinctly observed by highly-specific DNA-based ELISA, and by NF-κB-specific inhibitor, Bay 11–7082.
Results
The prepared AgNPs-CIT were spherical and have an absorption wavelength range of 381–452 nm wherein the particles size ranged between 19.2±0.1 to 220.77±0.12 nm with the charge range −9.99±0.8 to −34.63±0.1 mV. The prepared AgNPs-CIT showed comparative antioxidant activity at >40% inhibitions level of the DPPH radicals. The AgNPs-CIT were found to be non-toxic to MCF-7 cell-lines and inhibited PMA-induced activation of the NF-κBp65, and also the mRNA/protein expression of TNFα.
Conclusion
This is the first report that showed AgNPs-CIT inhibited TNFα expression via deactivation of the NF-κB signaling event in stimulated breast cancer cells. The results have important implications for the development of novel therapeutic strategies for the prevention/treatment of cancers and/or inflammatory disorders.
“…The TGA thermogram shows three different decomposition steps, until at about 660 °C. The first step until 180 °C can be attributed to water desorption, with a 2% weight loss; the second and third step (180-660 °C) is attributed to the partial decomposition of citrate in two steps, with CO 2 evolution (Marcilla et al 2018). The citrate coating of SPIONs constituted 7% of the total mass.…”
Surface derivatized magnetic nanoparticles have been commonly used for magnetic separation. Facile mechanisms are needed to be developed for the design of bio-functionalized magnetic hybrid materials, where the surfaces can be regenerated for the re-use of the developed platforms. Superparamagnetic iron oxide nanoparticles with a diameter below 10 nm were synthesized via a novel microwave-assisted hydrothermal method in the presence of citrate ions, which allowed to obtain uniform and negatively charged nanoparticles. These were then coupled with Poly-l-lysine (PLL), forming micrometersized self-assembled spherical entities. Cross-linking the PLL within these microspheres with glutaraldehyde stabilized them chemically and mechanically. The active bio-functionality was introduced by a protein grafting methodology, using m-maleimidobenzoyl-N-hydroxysulfosuccinimide ester (SMBS). The Moringa oleifera Coagulant Protein (MOCP) from a seed extract was employed for its characteristic coagulation activity. The performance of the MOCP functionalized microspheres was evaluated as a function of turbidity removal of problematic colloidal clay from water via magnetic separation, resulting in over 80% of activity within 15 min. Surface of these hybrid materials can be regenerated by treatment with alcohol, allowing their easy magnetic separation and re-use. The rapid and strong response with tunable magnetic property makes these hybrid microspheres a powerful tool for many potential applications, due to the general applicability of the developed methodology.
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