Synthesis of Zinc Oxide Nanoparticles and Their Effect on the Compressive Strength and Setting Time of Self-Compacted Concrete Paste as Cementitious Composites

In the present study, the mechanical properties of self-compacting concrete were investigated after the addition of different amounts of ZnO nanoparticles. The zinc oxide nanoparticles, with an average particle size of about 30 nm, were synthesized and their properties studied with the help of a scanning electron microscope (SEM) and X-ray diffraction. The prepared nanoparticles were partially added to self-compacting concrete at different concentrations (0.05, 0.1, 0.2, 0.5 and 1.0%), and the mechanical (flexural and split tensile) strength of the specimens measured after 7, 14, 21 and 28 days, respectively. The present results have shown that the ZnO nanoparticles were able to improve the flexural strength of self-compacting concrete. The increased ZnO content of more than 0.2% could increase the flexural strength, and the maximum flexural and split tensile strength was observed after the addition of 0.5% nanoparticles. Finally, ZnO nanoparticles could improve the pore structure of the self-compacted concrete and shift the distributed pores to harmless and less-harmful pores, while increasing mechanical strength

Synthesis of ZnO nanoparticles and their antibacterial effects

The zinc oxide nanoparticles with the average particle size of about 30 nm were synthesized by the chemical technique and their properties were studied with the help of scanning electron microscope and X-ray diffraction. The aim of this study was to detect the antibacterial properties of 0.01, 0.5 and 1% nano-ZnO against Escherichia coli. E. coli was cultured in liquid and agar nutrient medium to evaluate the antibacterial effects of 0.01, 0.05 and 1% of ZnO via the optical density (OD) and log CFU/ml measurements. Non-significant effect was seen for 0.01% of ZnO nano-particles, while 0.05 and 1% of nanoparticles showed considerably decreased bacterial number. A 4.385 and 2.04 times decrease in the OD value was found in the presence of 1 and 0.5% nano-ZnO, respectively (P<0.001) as compared to the control. In the second study, 6.3 log CFU/ml of E. coli were present in the cultures treated with 1% nano-ZnO at 4°C in water. Control E. coli cells survived for 12 days, while complete cell death was seen when 1% nano-ZnO was applied for 24 h. In the third study, E. coli was grown in the agar medium with and without nanoparticles and suppressed growth (8.56 times; P<0.001) was seen in the presence of 1% nano-ZnO.Keywords: ZnO-nanoparticle, antibacterial, bactericidal, Escherichia col

An Effector of Hemoglobin Structure: The Guanosine 3\u27, 5\u27-Triphosphate

The effect of guanosine 3\u27, 5\u27-triphosphate (GTP) on the hemoglobin structure was studied by UV-visible, fluorescence and circular dichroism (CD) spectroscopies, and cyclic voltammetry. UV-visible absorption spectra showed an increase in absorbance in the regions of 420 nm and 280 nm. Fluorescence spectra showed that the Trp fluorescence intensity increased upon excitation at 280 nm, when guanosine 3\u27, 5\u27-triphosphate concentration was increased in hemoglobin solution. Along with the increased fluorescence intensity, a slightly shift of λmax was also observed toward the higher wavelengths. CD spectral analysis demonstrated a significant decrease in negative ellipsity in the region of 205–235 nm. After adding guanosine 3\u27, 5\u27-triphosphate to the hemoglobin solution α-helix structure decreases by 20 % while β-sheet conformation increases by 9 %. The effects of GTP on hemoglobin resulted in a 61 mV shift in the cathodic and 40 mV for anodic peak of hemoglobin in the CD. Our data showed the change of secondary and tertiary structure of hemoglobin in the presence of guanosine 3\u27, 5\u27-triphosphate. (doi: 10.5562/cca1955

Direct Electron Transfer of Hemoglobin on Manganese III Oxide-Ag Nanofibers Modified Glassy Carbon Electrode

We investigated the electrochemical behavior of hemoglobin by glassy carbon electrode modified with Mn2O3-Ag nanofibers. The Mn2O3-Ag nanofibers were used as facilitator electron transfer between Hb and glassy-carbon-modified electrode. The Mn2O3-Ag nanofibers are studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The hemoglobin showed a quasireversible electrochemical redox behavior with a formal potential of −49 mV (versus Ag/AgCl) in 0.1 M potassium phosphate buffer solution at pH 7.0. The designed biosensor possesses good stability and reproducibility and achieves 95% of the steady-state current in less than five seconds

Electrochemical Recognition of Metalloproteins by Bromide-modified Silver Electrode - A New Method

A bromide–modified silver electrode is reported, in the present study, to catalyzethe redox reactions of metalloproteins. This study describes that the bromide ions showvery good redox behavior with silver electrode. The cathodic and anodic peak potentialswere related to the concentration of bromide ions involved in making bromide-modifiedsilver electrode. The electrode reaction in the bromine solution was a diffusion-controlledprocess. Positive potential shift of the bromide ions was seen when different proteins wereadded to the solution using a silver electrode. New cathodic and anodic peaks wereobserved at different potential ranges for myoglobin, cytochrome c and catalase. A linearlyincreasing cathodic peak current of bromide ions was seen when the concentration ofsuperoxide dismutase was increased in the test solution. However, no change for albuminwas observed when its concentration was increased in the test solution. Present data provesour methodology as an easy-to-use analysis for comparing the redox potentials of differentmetalloproteins and differentiating the metallo- from non-metalloproteins. In this study, weintroduced an interesting method for bio-electrochemical analyses

Characterization Study forNanocompositions of Methylene Blueand Riboflavin-Nafion on the Electrode Surface: Characterization of nanocompositions on electrode surface

Nafion is a perfluorinated anionic polyelectrolyte. The increasing popularity of nafion for the fabrication of redox polymer modified electrodes in recent years arises from easy fabrication, good electrical conductivity and high partition coefficients of many redox compounds in nafion. To investigate the production of nano-compositions by mixing electron transfer material and nafion polymer for the modification of electrodes, a functional membrane composed of nano-particles of methylene blue, and nafion was constructed. The materials were characterized by the methods of scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet (UV)-visible and FT-IR. The average diameter of new nano-particles was estimated to be about 60 nm. Anovel nafion-riboflavin membrane was also constructed and characterized by the methods of SEM, TEM and UV-visible spectroscopy. The estimated average diameter of new nanoparticles was about 60 nm. Our data has proven that nafion can be very interesting and helpful material in constructing nanoparticles of different electro-active materials and it can immobilize this material with a very good stability

Internet Journal of Food Safety Survey and Comparison of Sporecidal Property of CuO and AgO Nanoparticles upon Spore of Clostridium botulinum type E

Abstract Aims: In this paper examined sporecidal effect of metal oxide nanoparticles of silver and copper against bacteriu

A new strategy in improving therapeutic indexes of medicinal herbs: preparation and characterization of nano-liposomes containing Mentha piperita essential oil

Introduction: Herbal Compound and their essential oils possess high antimicrobial, antioxidant, and anti-tumor properties, but conventional prescribing of them faces serious challenges. Liposomal nano-carrier is one of the common pharmaceutical strategies to overcome these challenges. In this study, slow-released liposomal system containing Mentha piperita’s essential oil was prepared in order to improve its antimicrobial, antioxidant and antitumor properties. Methods: Liposomal vesicles were prepared using phosphatidylcholine (80%) and cholesterol (20%) by thin-film method. Mentha piperita’s essential oil were loaded into the liposomes using inactive loading method. Their physico-chemical features were assayed using Zeta-Sizer, FTIR and SEM, and at the end, the essential oil release amount was calculated at 37° C. Results: Liposomal vesicles containing Mentha piperita’s essential oil showed the size of 247  13.39 nm, 61.38% ± 2.7 essential oil encapsulation efficiency, -34.54  0.74 mV of zeta potential and polydispersity index (PDI) of 0.32  .01. The prepared liposomal system presented essential oil controlled release and FTIR and SEM investigation showed no interaction between nanocarrier and the essential oil and the carriers have spherical structures. Conclusion: In the present study, Mentha piperita’s essential oil encapsulated in liposomal carriers and its physicochemical properties investigated. The results confrimed the slow-releasing ability of system and also showed that the anionic nanosystem increased the essential oil’s stability without any change in its chemical nature. Taken together, liposomal nanocarrier could be a potent and suitable carrier for the essential oil

Comparative Study of Antimicrobial Activities of TiO 2 and CdO Nanoparticles against the Pathogenic Strain of Escherichia coli

ABSTRACT Background: and Objectives: The aim of this study was to detect the antibacterial properties o

Electrochemical Recognition of Metalloproteins by Bromide-modified Silver Electrode- A New Method

Abstract: A bromide–modified silver electrode is reported, in the present study, to catalyze the redox reactions of metalloproteins. This study describes that the bromide ions show very good redox behavior with silver electrode. The cathodic and anodic peak potentials were related to the concentration of bromide ions involved in making bromide-modified silver electrode. The electrode reaction in the bromine solution was a diffusion-controlled process. Positive potential shift of the bromide ions was seen when different proteins were added to the solution using a silver electrode. New cathodic and anodic peaks were observed at different potential ranges for myoglobin, cytochrome c and catalase. A linearly increasing cathodic peak current of bromide ions was seen when the concentration of superoxide dismutase was increased in the test solution. However, no change for albumin was observed when its concentration was increased in the test solution. Present data proves our methodology as an easy-to-use analysis for comparing the redox potentials of different metalloproteins and differentiating the metallo- from non-metalloproteins. In this study, we introduced an interesting method for bio-electrochemical analyses