scholarly journals Effects of synthesis conditions and storage on silver nanospheres chemically reduced by mulberry leaf extracts

2021 ◽  
Vol 19 (3) ◽  
pp. 172-183
Author(s):  
P. Pholnak ◽  
P. Khunsare ◽  
Y. Sirisathitkul ◽  
C. Sirisathitkul
Keyword(s):  
Particle Diameter ◽  
Synthesis Temperature ◽  
Surface Plasmon Resonance Peak ◽  
Leaf Extracts ◽  
Plasmon Resonance Peak ◽  
B Values ◽  
Synthesis Conditions ◽  
Mulberry Leaf ◽  
Hue Angle ◽  
20 Nm

Silver (Ag) nanospheres were chemically reduced from 1 mM silver nitrate (AgNO3) solutions using mulberry (Morus alba Linn.) leaf extracts. The increase of pH in the synthesis from 9 to 13 modified the surface plasmon resonance peak in UV-Vis spectra relating to the particle diameter around 20 nm. Smaller nanoparticles were obtained from the syntheses at pH 7.4-7.7 and their density was slightly increased with the increase in synthesis temperature from 25 °C to 90 °C. The particle size was increased with increasing AgNO3 concentration from 0.1 to 0.5 M but the mixed phases were obtained from the 0.5 M AgNO3 precursor. After storing for 10 months at room temperature, the nanosuspensions remained without Ag sediment but their colors had significantly changed due to particle agglomerations. The colors were characterized by the smartphone colorimetry according to the RGB, CIE space, as well as chroma and hue angle. Based on the chroma and CIE b* values, the effect of synthesis pH in the stored nanosuspensions was comparable to that before the storage. Although the temperature had only moderate effects, nanosuspensions synthesized at 25 °C, 80 °C, and 90 °C were clearly distinguished by the hue and CIE b* values.

scholarly journals Relation between Silver Nanoparticle Formation Rate and Antioxidant Capacity of Aqueous Plant Leaf Extracts

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Azat Akbal ◽  
M. Haluk Turkdemir ◽  
Ahmet Cicek ◽  
Bulent Ulug
Keyword(s):  
Antioxidant Capacity ◽  
Silver Nanoparticle ◽  
Plasmon Resonance ◽  
Average Particle Size ◽  
Average Particle ◽  
Surface Plasmon Resonance Peak ◽  
Leaf Extracts ◽  
Plasmon Resonance Peak ◽  
Plant Leaf ◽  
Nanoparticle Formation

Correlation between the antioxidant capacity and silver nanoparticle formation rates of pomegranate (Punica granatum), quince (Cydonia oblonga), chestnut (Castanea sativa), fig (Ficus carica), walnut (Juglans cinerea), black mulberry (Morus nigra), and white mulberry (Morus alba) leaf extracts is investigated at a fixed illumination. Silver nanoparticles formed in all plant leaf extracts possess round shapes with average particle size of 15 to 25 nm, whereas corresponding surface plasmon resonance peak wavelengths vary between 422 nm and 451 nm. Cupric reducing antioxidant capacity technique is used as a reference method to determine total antioxidant capacity of the plant leaf extracts. Integrated absorbance over the plasmon resonance peaks exhibits better linear relation with antioxidant capacities of various plant leaf extracts compared to peak absorbance values, with correlation coefficient values of 0.9333 and 0.7221, respectively.

Nanostructured Polymetallic Powders to Create New Functional Materials on its Base

2015 ◽  
Vol 670 ◽  
pp. 49-54 ◽  
Author(s):  
Yuriy A. Zaharov ◽  
Valeriy M. Pugachev ◽  
Kseniya A. Datiy ◽  
Anna N. Popova ◽  
Anastasiya S. Valnyukova ◽  
...  
Keyword(s):  
Particle Size ◽  
Phase Diagrams ◽  
Spatial Organization ◽  
Functional Materials ◽  
Particle Morphology ◽  
Cloud Type ◽  
Synthesis Conditions ◽  
Micron Size ◽  
Common Nature ◽  
20 Nm

In the paper, the particle morphology is considered and the slices of phase diagrams of nanosystems agreeable to the synthesis conditions are constructed according to the data obtained earlier by authors, as well as new results of the study of nanostructured Fe-Co, Fe-Ni, Co-Ni, Fe-Co-Ni, Fe-Pt, Cu-Ni and Ni-Cd powders. It is found that all considered polymetallic systems have common nature of the particle size spatial organization, i.e., 7-20 nm nanocrystals (for different systems) form highly compact aggregates (40-100 nm) which put together into loose porous agglomerates (up to 200-250 nm) and then into unconsolidated micron size formation of cloud type. It is classified uncovered features of nanostructured polymetallic phase diagrams in comparison with phase diagrams of bulk systems. Magnetic properties of nanosystems are studied.

scholarly journals A Comparative Evaluation of Nanohydroxyapatite-Enriched Hydrogen Peroxide Home Bleaching System on Color, Hardness and Microstructure of Dental Enamel

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3072
Author(s):  
Riccardo Monterubbianesi ◽  
Vincenzo Tosco ◽  
Tiziano Bellezze ◽  
Giampaolo Giuliani ◽  
Mutlu Özcan ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Particle Diameter ◽  
Dental Enamel ◽  
Sem Analysis ◽  
Control Group ◽  
Average Particle ◽  
Color Analysis ◽  
Enamel Microstructure ◽  
Prismatic Structure ◽  
20 Nm

This study aimed to evaluate two hydrogen peroxide (HP)-based at-home bleaching systems in order to analyze whether nano-hydroxyapatite (nHA) addition may represent a reliable and safe solution for tooth whitening without altering dental microstructure and hardness. Human third molars (N = 15) were treated with two bleaching agents, one containing 6%HP (6HP) and the other 6% HP nHA-enriched (6HP-nHA) with average particle diameter ranging from 5–20 nm. Their effects on enamel were assessed using a spectrophotometer, Vickers microhardness (VMH) test and Scanning Electron Microscopy (SEM), comparing the treated groups with the non-treated control group (CTR). Color analysis revealed improvement in whiteness in both groups compared to CTR. VMH test results showed no differences among the groups. SEM analysis highlighted no evident changes in the enamel microstructure of tested groups compared to CTR. At high magnification, in 6HP group, a slight increase in irregularities of enamel surface morphology was observed, while 6HP-nHA group displayed removal of the aprismatic layer but preservation of the intact prismatic structure. These results suggest that the 6HP-nHA agent may be recommended to provide reliable whitening treatment, without damaging the enamel micromorphology and hardness.

scholarly journals In vitro and in vivo applications of Euphorbia wallichii shoot extract-mediated gold nanospheres

2021 ◽  
Vol 10 (1) ◽  
pp. 101-111
Author(s):  
Rehman Ullah ◽  
Sumaira Shah ◽  
Zahir Muhammad ◽  
Sajjad Ali Shah ◽  
Shah Faisal ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Muscular Contraction ◽  
Surface Plasmon Resonance Peak ◽  
Plasmon Resonance Peak ◽  
Optical Absorption Peak ◽  
Visible Spectra ◽  
Scattering Spectra ◽  
Dose Dependent

Abstract The current study was designed to investigate the potential of Euphorbia wallichii shoot extract for reducting Au3+ and stabilizing gold nanoparticles. UV-visible spectra of gold nanoparticles showed obvious surface plasmon resonance peak at 548 nm. Microscopy (SEM and TEM) showed spherical dimensions, and the energy dispersive X-ray spectra displayed the strongest optical absorption peak for gold (Au) at 2.1 keV. Dynamic light scattering spectra represent polydispersed mixture with particulate diameter of 2.5–103.2 nm. The IR spectra confirm the potential functional groups of shoot extract responsible for the reduction of Au3+ to gold nanoparticles which exhibit tremendous antibacterial potential of 76.31%, 68.47%, 79.85%, 48.10%, and 65.53% against Escherichia coli, Staphylococcus aureus, Bacillus pumilus, Pseudomonas aeruginosa, and Klebsiella pneumoniae, respectively. Gold nanoparticles showed markedly elevated fungicidal potency compared to the shoot extract alone against the tested fungal strains. IC50 for 2,2-diphenyl-1-picrylhydrazyl scavenging was 31.52, 18.29, and 15.32 µg/mL at 30, 60, and 90 min of reaction time, respectively. Both shoot extract and nanoparticles revealed 71% mortality at 100 µg/mL, with LD90 values of 310.56 µg/mL. Experimental mice acquired dose-dependent analgesia of 54.21%, 82.60%, and 86.53% when treated with gold nanoparticles at 50, 100, and 200 mg/kg bw. Inhibition of gastrointestinal muscular contraction was 21.16%, 30.49%, and 40.19% in mice feed with 50, 100, and 200 mg/kg bw, respectively.

scholarly journals A method for detecting the presence of organic fraction in nucleation mode sized particles

2005 ◽  
Vol 5 (12) ◽  
pp. 3277-3287 ◽  
Author(s):  
P. Vaattovaara ◽  
M. Räsänen ◽  
T. Kühn ◽  
J. Joutsensaari ◽  
A. Laaksonen
Keyword(s):  
Sulfuric Acid ◽  
Field Experiments ◽  
Inorganic Compounds ◽  
Particle Diameter ◽  
Ethanol Vapor ◽  
Organic Fraction ◽  
Saturation Ratio ◽  
Nucleation Mode ◽  
Atmospheric Nucleation ◽  
20 Nm

Abstract. New particle formation and growth has a very important role in many climate processes. However, the overall knowlegde of the chemical composition of atmospheric nucleation mode (particle diameter, d<20 nm) and the lower end of Aitken mode particles (d≤50 nm) is still insufficient. In this work, we have applied the UFO-TDMA (ultrafine organic tandem differential mobility analyzer) method to shed light on the presence of an organic fraction in the nucleation mode size class in different atmospheric environments. The basic principle of the organic fraction detection is based on our laboratory UFO-TDMA measurements with organic and inorganic compounds. Our laboratory measurements indicate that the usefulness of the UFO-TDMA in the field experiments would arise especially from the fact that atmospherically the most relevant inorganic compounds do not grow in subsaturated ethanol vapor, when particle size is 10 nm in diameter and saturation ratio is about 86% or below it. Furthermore, internally mixed particles composed of ammonium bisulfate and sulfuric acid with sulfuric acid mass fraction ≤33% show no growth at 85% saturation ratio. In contrast, 10 nm particles composed of various oxidized organic compounds of atmospheric relevance are able to grow in those conditions. These discoveries indicate that it is possible to detect the presence of organics in atmospheric nucleation mode sized particles using the UFO-TDMA method. In the future, the UFO-TDMA is expected to be an important aid to describe the composition of atmospheric newly-formed particles.

BIOSYNTHESIZED SILVER NANOPARTICLES USING CATHARANTHUS ROSEUS AND THEIR ANTIBACTERIAL EFFICACY IN SYNERGY WITH ANTIBIOTICS; A FUTURE ADVANCEMENT IN NANOMEDICINE

2021 ◽  
pp. 116-124
Author(s):  
MONIKA GUPTA
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Catharanthus Roseus ◽  
Leaf Extract ◽  
Research Work ◽  
Resistant Bacteria ◽  
Surface Plasmon Resonance Peak ◽  
Plasmon Resonance Peak ◽  
X Ray ◽  
Uniform Dispersion

Objective: This research work develops an approach to synthesize silver nanoparticles (AgNPs) by reduction of leaf extract of Catharanthus roseus plant. This study produces synthesized nanoparticles that have process-controlled attributes which make their antibiotic action highly efficient. These attributes include smaller size, proper morphology, uniform dispersion, metal ion content, and formation of functional groups. By optimizing the reduction process parameters, AgNPs gain the desired properties.  Methods: The biosynthesis of AgNPs process was performed using reaction of 10% (w/v) C. roseus leaf extract with AgNO3. The optimum conditions and concentration used for synthesis of nanoparticles were: 1 mM AgNO3, pH 5, and temperature 80°C with an incubation time of 72 h. All the above parameters were analyzed by ultraviolet-visible spectrophotometer with the surface plasmon resonance peak obtained at 440 nm. Results: Various characterization techniques were performed, namely, scanning electron microscopy, energy-dispersive X-ray, transmission electron microscopy, photoluminescence study, X-ray diffraction spectroscopy, Fourier transform infrared, dynamic light scattering, and atomic force microscopy. The results obtained from characterization confirmed the spherical morphology of the nanoparticles with size between 50 and 87 nm. In the current investigation, the antimicrobial activity of biosynthesized AgNPs was also determined using minimum inhibitory concentration and zone of inhibition methods against six different bacteria at different doses of AgNPs (100, 150, and 200 μg/ml) alone and also in combination with antibiotic-streptomycin. Conclusion: The results revealed that high concentration of AgNPs inhibits the bacterial growth. Furthermore, AgNPs revealed much stronger antibacterial action in synergy with streptomycin against antibiotic-resistant bacteria.

scholarly journals Summertime observations of ultrafine particles and cloud condensation nuclei from the boundary layer to the free troposphere in the Arctic

2016 ◽  
Author(s):  
Julia Burkart ◽  
Megan D. Willis ◽  
Heiko Bozem ◽  
Jennie L. Thomas ◽  
Kathy Law ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Ultrafine Particles ◽  
Cloud Condensation Nuclei ◽  
Particle Diameter ◽  
Open Ocean ◽  
The Arctic ◽  
Condensation Nuclei ◽  
Aerosol Composition ◽  
Low Level ◽  
20 Nm

Abstract. The Arctic is extremely sensitive to climate change. Shrinking sea ice extent increases the area covered by open ocean during Arctic summer, which impacts the surface albedo and aerosol and cloud properties among many things. In this context extensive aerosol measurements (aerosol composition, particle number and size, cloud condensation nuclei, and trace gases) were made during 11 flights of the NETCARE July, 2014 airborne campaign conducted from Resolute Bay, Nunavut (74N, 94W). Flights routinely included vertical profiles from about 60 to 3000 m a.g.l. as well as several low-level horizontal transects over open ocean, fast ice, melt ponds, and polynyas. Here we discuss the vertical distribution of ultrafine particles (UFP, particle diameter, dp: 5–20 nm), size distributions of larger particles (dp: 20 nm to 1 μm), and cloud condensation nuclei (CCN, supersaturation = 0.6 %) in relation to meteorological conditions and underlying surfaces. UFPs were observed predominantly within the boundary layer, where concentrations were often several hundreds to a few thousand particles per cubic centimeter. Occasionally, particle concentrations below 10 cm−3 were found. The highest UFP concentrations were observed above open ocean and at the top of low-level clouds, whereas numbers over ice-covered regions were substantially lower. Overall, UFP formation events were frequent in a clean boundary layer with a low condensation sink. In a few cases this ultrafine mode extended to sizes larger than 40 nm, suggesting that these UFP can grow into a size range where they can impact clouds and therefore climate.

scholarly journals Effect of Ammonium Nitrate on Nanoparticle Size Reduction

2008 ◽  
Vol 2008 ◽  
pp. 1-4 ◽  
Author(s):  
Kalyana C. Pingali ◽  
Shuguang Deng ◽  
David A. Rockstraw
Keyword(s):  
Ammonium Nitrate ◽  
Metallic Nanoparticles ◽  
Particle Diameter ◽  
Feed Solution ◽  
Pyrolysis Process ◽  
Foaming Agent ◽  
Aerosol Droplet ◽  
Order Of Magnitude ◽  
Spray Pyrolysis Process ◽  
20 Nm

Ammonium nitrate was added to the spraying solution as a foaming agent to reduce the particle size of nanoparticles synthesized in the spray-pyrolysis process. Ammonium nitrate was effective in breaking the aerosol droplet size and generating nanoparticles that were of approximately one order-of-magnitude (from 200 to 20 nm) smaller diameter than those created in the absence of ammonium nitrate in the feed solution. This technique makes it possible to control the particle diameter of metallic nanoparticles below 20 nm.

scholarly journals Effect of Different Antimicrobial Applications on Color Stability of Ground Pork

2019 ◽  
Vol 3 (2) ◽  
Author(s):  
H. D. Garnica ◽  
M. F. Miller ◽  
D. A. Vargas ◽  
A. R. English ◽  
K. E. Hanlon ◽  
...  
Keyword(s):  
Peracetic Acid ◽  
Storage Period ◽  
Color Stability ◽  
The Other ◽  
Color Analysis ◽  
B Values ◽  
Positive Effects ◽  
Ph Values ◽  
Ground Pork ◽  
Hue Angle

ObjectivesThe purpose of the study was to evaluate color changes during dark storage of ground pork following application with one of three different antimicrobial interventions to pork trim.Materials and MethodsTreatments included a control (no antimicrobial), lactic acid (LA; 3%), PAA+Titon [sulfuric acid and sodium sulfate (pH 1.3) combined with peracetic acid (350 ppm)], PAA+Acetic [peracetic acid (400 ppm) with 2% acetic acid]. Four 22.7-kg batches of pork trim were treated with one intervention, ground [coarse (3/16’’) followed by a fine (1/8”) grind] and packaged in 454-g rollstock vacuum packaging (n = 40/treatment). After random assignment to an aging time (0, 7, 14, 21, or 28 d), product was held under dark storage at 2–4°C. On each storage day, samples (n = 8/treatment) were opened and L*, a*, and b* values were taken using a HunterLab Miniscan XE spectrophotometer at 0 min, 10 min, and 20 min for bloom color analysis, with hue angle [arctangent (b*/a*)] and chroma [ (a* + b*)1/2 ] calculated from a* and b* values. For pH, 5 g of sample and 90 mL of distillated water were homogenized and analyzed with a bench top pH probe. Finally, fat, moisture, and protein percentage were determined using a FOSS FoodScan. Statistical analysis was conducted using the GLM procedure of SAS with a means separation using the Tukey adjustment and significance set at P < 0.05.ResultsProximate analysis of the ground pork in this study showed 20.04 ± 1.13% for fat, 61.15 ± 1.11% for moisture, and 16.83 ± 0.39% for protein content. For initial pork color, at 0 min, LA had greater L* values compared to PAA+Titon at 0d, 7d and 14d (P < 0.05), but no treatment differences were detected in L* values at 21d and 28d (P > 0.05). After 10 min of bloom time, PAA+Titon maintained the highest chroma value throughout all aging days (P < 0.05) demonstrating the most color intensity. At 21d PAA+Titon increased blooming properties through 20min (P < 0.05), based on a*, while control samples had no bloom development (P > 0.05). At 21d and 28d aging LA hue angle was highest (P < 0.05) indicating more potential metmyoglobin discoloration. PAA+Titon presented the highest pH values compared to all the other treatments for each day during the storage period except for Day 14, while LA presented lower values compared to all the other treatments for each day (P < 0.05).ConclusionAs an organic acid application on pork trim prior to grinding, PAA+Titon demonstrates positive effects on color of ground pork based on color and pH values, after post-grinding storage.

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