scholarly journals Supramolecular Assembly and Reversible Transition and of Chitosan Fluorescent Micelles by Noncovalent Modulation

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
An Liu ◽  
Hong Song ◽  
Puyou Jia ◽  
Ying Lin ◽  
Qingping Song ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Fluorescence Intensity ◽  
Ph Value ◽  
Low Cost ◽  
Fluorescence Emission ◽  
Temperature Response ◽  
Supramolecular Assembly ◽  
Water Soluble ◽  
Solution Ph ◽  
Reversible Transition

Chitosan-based intelligent artificial systems have been of increasing interest for their biocompatibility, multifunctionality, biological activity, and low cost. Herein, we report the fabrication of supramolecular nanoparticles based on water-soluble chitosan (WCS) and 1,1 ′ ,1 ″ ,1 ″ ′ -(ethene-1,1,2,2-tetrayl)tetrakis(benzene-4,1-diyl) tetrakis(azanediyl)tetraacetic acid (TPE-(N-COOH)4), which is capable of reversible transition between polyion complexes (PICs) and hydrogen bonding complexes (HBCs) with tunable aggregation-induced emission driven by pH value. The PIC micelles could be formed via electrostatic interaction between ammonium cations and carboxylate anions under mild alkaline conditions. The formation of the micelles dramatically blocks the nonradiative pathway and enhances the fluorescence of TPE moieties, and the maximum fluorescence intensity was achieved near the isoelectric point due to the restriction of intramolecular motion. In addition, the fluorescence intensity and size of the PIC micelles exhibited a temperature response in the range from 20 to 80°C. Upon adjusting the solution pH to 2, the PIC micelles were reconstructed into hydrogen-bonding complexes while the hydrogen bonding interaction between the protonated carboxyl groups of TPE-(N-COOH)4 and chitosan. Moreover, the size of the micelles underwent a remarkable decrease, whereas the fluorescence emission was further enhanced by ~6.25-fold. The pH actuated micellar transition from PIC to HBC with tunable fluorescence performance is fully reversible. This study provides novel multifunctional materials that are of great importance for their potential application in the fields of optoelectronic devices and chemical and biomedical sensors.

scholarly journals Adding distiller's grains and molasses on fermentation quality of rice straw silages

2016 ◽  
Vol 46 (12) ◽  
pp. 2235-2240 ◽  
Author(s):  
XianJun Yuan ◽  
ZhiHao Dong ◽  
Seare Tajebe Desta ◽  
AiYou Wen ◽  
Xiaoxuan Zhu ◽  
...  
Keyword(s):  
Rice Straw ◽  
Ph Value ◽  
Low Cost ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Distiller's Grains ◽  
Cost Strategy ◽  
Fermentation Quality ◽  
Low Cost Strategy

ABSTRACT: Ensilage is a simple and low-cost strategy to enable long term preservation and environmentally friendly utilization of agricultural by-products, such as straws and distiller's grains (DG) for ruminants. Effect of mixing different proportions of DG and rice straw (i.e. 0, 10, 20 or 30% of DG) with or without 5% molasses addition on fermentation and chemical variables of silages was evaluated. The study was conducted as a randomized blocks design in a 4 × 2 factorial arrangement, with three replications, using laboratory silos of 1L capacity (n=24). Despite a significant interaction (P<0.01) between DG and molasses addition was observed for most variables, in general the increased addition of DG linearly decreased the pH value, acetic acid (AA), butyric acid (BA) and ammonia N concentration (P<0.01), and increased the lactic acid (LA) concentration (P<0.01). Exception was the propionic acid concentration which linearly decreased without molasses addition and linearly increased with molasses addition at increased proportion of DG (P<0.01). In both silages with or without molasses the addition of DG increased the dry matter, water soluble carbohydrates and crude protein (P<0.01), and decreased the NDF content (P<0.01). Based on the perspective of maximum utilization of rice straw, the mixture of 10% of DG associated to 5% molasses at ensilage process is recommended.

Green Synthesis of Multifunctional Carbon Nanodots and Their Applications as a Smart Nanothermometer and Cr(VI) Ions Sensor

NANO ◽  
2018 ◽  
Vol 13 (12) ◽  
pp. 1850147 ◽  
Author(s):  
Lu Li ◽  
Congying Shao ◽  
Qian Wu ◽  
Yunjian Wang ◽  
Mingzhu Liu
Keyword(s):  
Fluorescence Intensity ◽  
Low Cost ◽  
Inner Filter Effect ◽  
Water Soluble ◽  
Carbon Nanodots ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
One Step ◽  
Apple Peels

In this work, water-soluble and blue-emitting carbon nanodots (CDs) were synthesized from apple peels for the first time via one-step hydrothermal method. The synthetic route is facile, green, economical and viable. The as-prepared CDs were characterized thoroughly by transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman, Fourier transform infrared (FT-IR), X-ray photoelectron (XPS), fluorescence and UV–Vis absorption spectroscopy in terms of their morphology, surface functional groups and optical properties. The results show that these CDs possessed ultrasmall size, good dispersivity, and high tolerance to pH, ionic strength and continuous UV irradiation. Significantly, the CDs had fast and reversible response towards temperature, and the accurate linear relationship between fluorescence intensity and temperature was used to design a novel nanothermometer in a broad temperature range from 5 to 65[Formula: see text]C facilely. In addition, the fluorescence intensity of CDs was observed to be quenched immediately by Cr(VI) ions based on the inner filter effect. A low-cost Cr(VI) ions sensor was proposed employing CDs as fluorescent probe, and it displayed a wide linear range from 0.5 to 200[Formula: see text][Formula: see text]M with a detection limit of 0.73[Formula: see text][Formula: see text]M. The practicability of the developed Cr(VI) sensor for real water sample assay was also validated with satisfactory recoveries.

Kinetic and Equilibrium of Biosorption of Methylene Blue by Sunflower Straw

2012 ◽  
Vol 610-613 ◽  
pp. 194-197
Author(s):  
Li Ping Chen ◽  
Si Qin Dalai
Keyword(s):  
Methylene Blue ◽  
Ph Value ◽  
Low Cost ◽  
Order Equation ◽  
Solution Ph ◽  
Biosorption Process ◽  
Optimum Ph ◽  
Pseudo Second Order ◽  
Batch Biosorption ◽  
Sunflower Straw

With sunflower straw as low-cost biosorbent, the biosorption of methylene blue (MB) from aqueous solution was studied by batch biosorption technique. The biosorption experiments were carried out under different conditions of solution pH, sunflower straw dose, and temperature. The results showed that biosorption of MB on to sunflower straw affected remarkably by the pH value, and the maximum biosorption amount was achieved at an optimum pH of 12.0; the equilibrium biosorption amount decreased as temperature was increasing, and the biosorption process might be depicted primly by Langmuir function; It was shown that the biosorption of methylene blue could be described by the pseudo-second-order equation.

scholarly journals Sorption of Pb(II) and Cu(II) by low-cost magnetic eggshells-Fe3O4 powder

2012 ◽  
Vol 18 (2) ◽  
pp. 221-231 ◽  
Author(s):  
Jianwei Ren ◽  
Mokgadi Bopape ◽  
Katlego Setshedi ◽  
Jacob Kitinya ◽  
Maurice Onyango
Keyword(s):  
Metal Ions ◽  
Ph Value ◽  
Low Cost ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Solution Ph ◽  
Freundlich Adsorption Isotherm ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Media Interaction

This study explored the feasibility of using magnetic eggshell-Fe3O4 powder as adsorbent for the removal of Pb(II) and Cu(II) ions from aqueous solution. The metal ionsadsorption media interaction was characterized using XRD and FTIR. The effects of contact time, initial concentrations, temperature, solution pH and reusability of the adsorption media were investigated. The metal ions adsorption was fast and the amount of metal ions adsorbed increased with an increase in temperature, suggesting an endothermic adsorption. The kinetic data showed that the adsorption process followed the pseudo-second-order kinetic model. The optimal adsorption pH value was around 5.5 at which condition the equilibrium capacity was 263.2 mg/g for Pb(II) and 250.0 for Cu(II). The adsorption equilibrium data fitted very well to the Langmuir and Freundlich adsorption isotherm models. The thermodynamics of Pb(II) and Cu(II) adsorption onto the magnetic eggshell-Fe3O4 powder indicated that the adsorption was spontaneous. The reusability study has proven that magnetic eggshell-Fe3O4 powder can be employed as a low-cost and easy to separate adsorbent.

Application of CdTe Quantum Dots to Development Fingerprints on Adhesive Surfaces

2011 ◽  
Vol 694 ◽  
pp. 874-880 ◽  
Author(s):  
Rui Qin Yang ◽  
Yong Gang Wang ◽  
Bin Bin Xia ◽  
Yan Ji Wang ◽  
Jian Jun Liu
Keyword(s):  
Quantum Dots ◽  
Fluorescence Spectroscopy ◽  
Fluorescence Intensity ◽  
Development Time ◽  
Ph Value ◽  
Development Rate ◽  
Water Soluble ◽  
Cdte Quantum Dots ◽  
Cdte Qds ◽  
Effective Development

Water-soluble fluorescent CdTe quantum dots were synthesized using TGA (Thiolglycolic acid) as the stabilizer and characterized by fluorescence spectroscopy. This fluorescent material was applied to development fingerprints deposited on the sticky side of adhesives. The development conditions such as development time, temperature and pH value of QDs solution were investigated. The comparison experimental with traditional methods and development rate were also studied. The results show that this material exhibited strong visible fluorescence under excitation at 365 nm. CdTe QDs can detect fingerprints on different adhesive surfaces. In addition, the development rate of fingerprints on the adhesive side of cellulose tape was discussed and the effective development rate for 30-days-aged fingerprints can reach to 72%. Furthermore, the developed fingerprints have higher and stable fluorescence intensity, weaker background interference and better contrast between fingerprints and the substrate. CdTe QDs is a promising reagent for fingerprints development on adhesive surfaces.

Effect of solution pH value changes on fluorescence intensity of magnetic-luminescent Fe3O4@Gd2O3:Eu3+ nanoparticles

2016 ◽  
Vol 34 (1) ◽  
pp. 71-76 ◽  
Author(s):  
Tuo WU ◽  
Huayan PAN ◽  
Rubiao CHEN ◽  
Dong LUO ◽  
Hong ZHANG ◽  
...  
Keyword(s):  
Fluorescence Intensity ◽  
Ph Value ◽  
Solution Ph ◽  
Value Changes

scholarly journals Schiff bases of 1,5-diarylpent-4-ene-1,3-diones and their metal complexes: Synthesis, characterization and fluorescent studies

2020 ◽  
pp. 62-62
Author(s):  
Muhammed Ummathur ◽  
Radhika Pallikkavil ◽  
Krishnannair Krishnankutty
Keyword(s):  
Hydrogen Bonding ◽  
Schiff Base ◽  
Metal Complexes ◽  
Spectral Data ◽  
Schiff Bases ◽  
1H Nmr ◽  
Fluorescence Intensity ◽  
Metal Ion ◽  
Fluorescence Emission ◽  
Fluorescent Studies

Four Schiff bases (H2L1 to H2L4) have been synthesized by the con-densation between o-aminophenol and unsaturated diketones (1,5-diarylpent-4--ene-1,3-diones). Analytical, IR, 1H NMR and mass spectsral data revealed their existence in the imine-enamine form. Dibasic tetradentate coordination of the Schiff bases in their ML complexes [M = Cu(II), Ni(II), Co(II), Zn(II), Cd(II), and Hg(II)] has been established on the basis of physical, analytical and spectral data. The fluorescent studies of H2L4 show that fluorescence emission maxima shift with increase in polarity and hydrogen bonding ability of the solvent. Paramagnetic Cu(II), Ni(II) and Co(II) ions decrease the fluorescence intensity with increase in concentration of the metal ion while diamagnetic Zn(II), Cd(II) and Hg(II) ions have very little influence on the intensity of fluorescence of the Schiff base H2L4.

Molecularly Imprinted Sensor for Ascorbic Acid Based on Gold Nanoparticles and Multiwalled Carbon Nanotubes

2020 ◽  
Vol 16 (7) ◽  
pp. 905-913
Author(s):  
Youyuan Peng ◽  
Qingshan Miao
Keyword(s):  
Carbon Nanotubes ◽  
Gold Nanoparticles ◽  
Ascorbic Acid ◽  
Multiwalled Carbon Nanotubes ◽  
Ph Value ◽  
Biological Fluids ◽  
Water Soluble ◽  
Multiwalled Carbon ◽  
Experimental Conditions ◽  
Molecularly Imprinted

Background: L-Ascorbic acid (AA) is a kind of water soluble vitamin, which is mainly present in fruits, vegetables and biological fluids. As a low cost antioxidant and effective scavenger of free radicals, AA may help to prevent diseases such as cancer and Parkinson’s disease. Owing to its role in the biological metabolism, AA has also been utilized for the therapy of mental illness, common cold and for improving the immunity. Therefore, it is very necessary and urgent to develop a simple, rapid and selective strategy for the detection of AA in various samples. Methods: The molecularly imprinted poly(o-phenylenediamine) (PoPD) film was prepared for the analysis of L-ascorbic acid (AA) on gold nanoparticles (AuNPs) - multiwalled carbon nanotubes (MWCNTs) modified glass carbon electrode (GCE) by electropolymerization of o-phenylenediamine (oPD) and AA. Experimental parameters including pH value of running buffer and scan rates were optimized. Scanning electron microscope (SEM), fourier-transform infrared (FTIR) spectra, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were utilized for the characterization of the imprinted polymer film. Results: Under the selected experimental conditions, the DPV peak currents of AA exhibit two distinct linear responses ranging from 0.01 to 2 μmol L-1 and 2 to 100 μmol L-1 towards the concentrations of AA, and the detection limit was 2 nmol L-1 (S/N=3). Conclusion: The proposed electrochemical sensor possesses excellent selectivity for AA, along with good reproducibility and stability. The results obtained from the analysis of AA in real samples demonstrated the applicability of the proposed sensor to practical analysis.

Nitrogen and Sulfur Co-doped Fluorescent Carbon Dots for the Detection of Morin and Cell Imaging

2018 ◽  
Vol 15 (1) ◽  
pp. 47-55
Author(s):  
Xuebing Li ◽  
Haifen Yang ◽  
Ning Wang ◽  
Tijian Sun ◽  
Wei Bian ◽  
...  
Keyword(s):  
Microwave Heating ◽  
Fluorescent Probe ◽  
Fluorescence Intensity ◽  
Carbon Dots ◽  
Cell Imaging ◽  
Water Soluble ◽  
Heating Process ◽  
X Ray ◽  
Doped Carbon Dots ◽  
Co Doped

Background: Morin has many pharmacological functions including antioxidant, anticancer, anti-inflammatory, and antibacterial effects. It is commonly used in the treatment of antiviral infection, gastropathy, coronary heart disease and hepatitis B in clinic. However, researches have shown that morin is likely to show prooxidative effects on the cells when the amount of treatment is at high dose, leading to the decrease of intracellular ATP levels and the increase of necrosis process. Therefore, it is necessary to determine the concentration of morin in biologic samples. Method: Novel water-soluble and green nitrogen and sulfur co-doped carbon dots (NSCDs) were prepared by a microwave heating process with citric acid and L-cysteine. The fluorescence spectra were collected at an excitation wavelength of 350 nm when solutions of NSCDs were mixed with various concentrations of morin. Results: The as-prepared NSCDs were characterized by transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The fluorescence intensity of NSCDs decreased significantly with the increase of morin concentration. The fluorescence intensity of NSCDs displayed a linear response to morin in the concentration 0.10-30 μM with a low detection limit of 56 nM. The proposed fluorescent probe was applied to analysis of morin in human body fluids with recoveries of 98.0-102%. Conclusion: NSCDs were prepared by a microwave heating process. The present analytical method is sensitive to morin. The quenching process between NSCDs and morin is attributed to the static quenching. In addition, the cellular toxicity on HeLa cells indicated that the as-prepared NSCDs fluorescent probe does not show obvious cytotoxicity in cell imaging. Our proposed method possibly opens up a rapid and nontoxic way for preparing heteroatom doped carbon dots with a broad application prospect.

Non-enzymatic determination of purine nucleotides using a carbon dot modified glassy carbon electrode

2019 ◽  
Vol 11 (30) ◽  
pp. 3866-3873 ◽  
Author(s):  
R. Karthikeyan ◽  
D. James Nelson ◽  
S. Abraham John
Keyword(s):  
Glassy Carbon ◽  
Low Cost ◽  
Phosphate Buffer Solution ◽  
Purine Nucleotides ◽  
Buffer Solution ◽  
Solution Ph ◽  
Carbon Dot ◽  
Enzymatic Determination ◽  
Sensitive Determination

Selective and sensitive determination of one of the purine nucleotides, inosine (INO) using a low cost carbon dot (CD) modified glassy carbon (GC) electrode in 0.2 M phosphate buffer solution (pH 7.2) was demonstrated in this paper.

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