Preparation and Characterization of Silver/Hydroxyapatite Nanoparticles

2011 ◽  
Vol 311-313 ◽  
pp. 1746-1750 ◽  
Author(s):  
Chao Guo ◽  
Xin Xin Li ◽  
Yin Sheng Dong
Keyword(s):  
Chemical Reduction ◽  
Diffusion Method ◽  
Face Centered Cubic ◽  
Mass Ratio ◽  
Hydroxyapatite Nanoparticles ◽  
E Coli ◽  
Nucleation Effect ◽  
Significant Difference ◽  
Face Centered

Aggregation problem limits the use of silver nanoparticles (nano-Ag). Liquid chemical reduction method was used to fabricate silver/hydroxyapatite nanoparticles (nano-Ag/HA) by depositing nano-Ag on the surface of hydroxyapatite nanoparticles (nano-HA). The XRD result shows nano-Ag/HA is a hybrid composite of hydroxyapatite and face-centered cubic crystalline silver. The TEM result confirms the size and distribution of nano-Ag are dependent on the mass ratio of deposited nano-Ag and nano-HA, decreasing the mass ratio can obtain nano-Ag with smaller size and less particle aggregation, which can be contributed to the heterogeneous nucleation effect of nano-HA on nano-Ag. Silver/hydroxyapatite/alginate composite dressing was fabricated by spraying nano-Ag/HA onto the surface of the alginate dressing. The test result of disc diffusion method shows the evident antimicrobial activity against Escherichia coli (E. coli) is assigned to nano-Ag/HA, no significant difference can be found between the dressings with 0.01g and 0.02g nano-Ag.

Synthesis and Fabrication of PVA-Ag-Cu and PANI-Ag-Cu Nanocomposite Thin Film Sensor for Detection of E. coli in Water

2014 ◽  
Vol 911 ◽  
pp. 131-135 ◽  
Author(s):  
H. Abdullah ◽  
Noor Azwen Noor Azmy ◽  
Norshafadzila Mohammad Naim ◽  
Aisyah Bolhan ◽  
Aidil Abdul Hamid ◽  
...  
Keyword(s):  
Thin Films ◽  
Chemical Reduction ◽  
Oxidative Polymerization ◽  
Face Centered Cubic ◽  
High Concentration ◽  
Film Sensor ◽  
E Coli ◽  
Host Materials ◽  
Face Centered ◽  
Xrd Patterns

Polymers are excellent host materials for nanoparticles of metals and semiconductors. PVAAgCu nanocomposite was synthesized from chemical reduction, whereas PANIAgCu nanocomposite was synthesized by chemical oxidative polymerization. PVAAgCu and PANIAgCu thin films were deposited on the glass substrate by spin coating technique. The films were characterized by using XRD and AFM. The sensitivity of the samples was analyzed by IV measurement. The peaks in XRD patterns confirm the presence of Ag-Cu nanoparticles in face centered cubic structure. AFM images show the roughness of PVAAgCu and PANIAgCu increased as Ag concentration decreased and Cu concentration increased. I-V measurements indicate that the change in the current of the films increases with the presence of E. coli. The sensitivity on E. coli increases for PVAAgCu and PANIAgCu thin films with high concentration of Cu.

scholarly journals ANALYSIS OF STRUCTURE AND ANTIMICROBIAL ACTIVITY OF CeO2 AND Nd2O3 NANOPARTICLES

2019 ◽  
Vol 4 (3) ◽  
pp. 105-112
Author(s):  
Hanif Yuliani ◽  
Rina Dewi Mayasari ◽  
Eryanti Kalembang ◽  
Yelvia Deni ◽  
Defi Rahma Santi ◽  
...  
Keyword(s):  
Neodymium Oxide ◽  
Precipitation Method ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
E Coli ◽  
Gram Positive Bacteria ◽  
Pathogen Inhibition ◽  
Face Centered

Cerium oxide (CeO2) and Neodymium oxide (Nd2O3) nanoparticles using local content have been synthesized by precipitation method. The CeO2 and Nd2O3 nanoparticles were characterized by X-Ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) to analyze the material phase and structure. The XRD spectrum shows that CeO2 and Nd2O3 nanoparticles have face-centered cubic and hexagonal, and cubic, respectively. The anti-microbial activity of CeO2 and Nd2O3 nanoparticles was analyzed by diffusion method using gram-negative bacteria (E. coli, S. aureus, P. aeruginosa), and gram-positive bacteria (S. entericatyphi, L. monocyogenes), and fungus (C. albicans). The result confirms that CeO2 and Nd2O3 nanoparticles have the capability of microbial pathogen inhibition. The CeO2 nanoparticles have the effective activities of inhibition for the microbial of S. aureus and S. entericatyphi, whereas Nd2O3 nanoparticles can inhibit the microbial of P. aeruginosa, S. entericatyphi, and  L. monocyogenes.

Preparation and Characterization of Silver Powders with Spheric Shape and Different Sizes

2010 ◽  
Vol 152-153 ◽  
pp. 1805-1809
Author(s):  
Ming Li Li ◽  
Kun Ming Qian ◽  
Qiong Yu ◽  
Yu Song Zhou ◽  
Song Ji ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Chemical Reduction ◽  
Silver Ions ◽  
Face Centered Cubic ◽  
Dispersing Agent ◽  
Transmission Electron ◽  
Particle Size Analyzer ◽  
Tap Density ◽  
Face Centered

The preparation and characterization of silver powders with spheric shape and different sizes by chemical reduction of silver ions in the presence of ethanol amine using hydrochinone (C6H6O2) as the reducing agent are described. The size distribution, microstructure, and the phase composition of the obtained Ag Powders were characterized by the Laser Particle Size Analyzer, Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) and the X-ray diffraction (XRD). The Ag powder was in face-centered cubic crystal structure with spheric morphology. The average tap density of silver powders is up to 4.0g/cm3. It was also found that the size of the Ag particles can be adjusted conveniently to a certain degree by varying the silver ions content, the addition amount of dispersing agent, the aging time, the temperature of the reaction, and the concentration ratio of hydrochinone to Ag+.

scholarly journals Characterization of bacteriocin and chitinase producing bacterial isolates with broad-spectrum antimicrobial activities

2021 ◽  
Vol 3 (8) ◽  
Author(s):  
Muhammad Yasir ◽  
Basit Zeshan ◽  
Nur Hardy A. Daud ◽  
Izzah Shahid ◽  
Hafza Khalid
Keyword(s):  
Antimicrobial Activity ◽  
Inhibitory Activity ◽  
Antifungal Drugs ◽  
Proteinase K ◽  
Diffusion Method ◽  
List Type ◽  
Bacterial Isolates ◽  
E Coli ◽  
Inhibitory Potential

Abstract There is a need for more efficient and eco-friendly approaches to overcome increasing microbial infections. Bacteriocins and chitinases from Bacillus spp. can be powerful alternatives to conventional antibiotics and antifungal drugs, respectively. The purpose of this study was to assess the inhibitory potential of bacteriocins and chitinase enzymes against multiple resistant bacterial and fungal pathogens. Bacterial isolates were selected by growth on minimal salts medium and after that were morphologically and biochemically characterized. The physiochemical characterization of bacteriocins was carried out. The inhibitory potential of bacteriocins towards six pathogenic bacteria was determined by the well diffusion assay while chitinase activity towards three fungal strains was determined by the dual plate culture assay. Two bacterial strains (WW2P1 and WRE4P2), out of nine showed inhibition of K. pneumonia, P. aeruginosa, E. coli and MRSA while WW4P2 was positive against S. typhimurium and E. coli and WRE10P2 against P. aeruginosa, S. pneumoniae. Two bacterial isolates (WW3P1 and WRE10P2) were chosen for further study on the basis of their antifungal activities. Of these, WW3P1 isolate was more effective against A. fumigatus as well as A. niger. The proteinaceous nature of the bacteriocins was confirmed by treatment of the crude extract with proteinase K. It was found that the inhibitory activity of strain WW3P1 against E. coli was highest at 20 °C, and against S. pneumoniae it was at 20 °C and pH 10 after treatment with EDTA. Inhibition by strain the WRE10P2 against P. aeruginosa was highest at 20 °C and pH 14. It was found that EDTA increased the inhibitory activity of strain WW2P1 against P. aeruginosa, K. pneumoniae and E. coli by 2 ± 0.235, 3.5 ± 0.288, 2.5 ± 1.040 times, respectively, of strain WRE4P2 against P. aeruginosa and E. coli by 2.5 ± 0.763, 2.7 ± 0.5 times, respectively, and of strain WRE10P2 against S. pneumoniae by 3 ± 0.6236 times. The isolates have promising inhibitory activity, which should be further analyzed for the commercial production of antimicrobials. Article highlights The current study aimed to isolate the microbiome from wheat plant (Triticum aestivum L.), to screen for bacteriocin production and to assess its antimicrobial activity against human pathogens. Forty-one phenotypically different bacterial colonies were subjected to bacteriocin purification from which 25 colonies showed positive reactions. These 25 bacterial isolates were screened against six different human bacterial pathogens using the well diffusion method to check the antimicrobial activity. Out of nine bacterial isolates, WW3P1 and WRE10P2 were able to degrade the chitin and utilize it as their sole energy source. Strain WRE4P2 exhibited partial inactivation in its activity against MRSA after treatment with proteinase K.

scholarly journals Characterization of cefotaxime resistant Escherichia coli isolated from broiler farms in Ecuador

2018 ◽  
Author(s):  
Christian Vinueza-Burgos ◽  
David Ortega-Paredes ◽  
Cristian Narváez ◽  
Lieven De Zutter ◽  
Jeannete Zurita
Keyword(s):  
Antimicrobial Resistance ◽  
Latin American ◽  
Production Systems ◽  
Diffusion Method ◽  
Poultry Production ◽  
Disk Diffusion Method ◽  
E Coli ◽  
Resistance Patterns ◽  
Latin American Countries

AbstractAntimicrobial resistance (AR) is a worldwide concern. Up to a 160% increase in antibiotic usage in food animals is expected in Latin American countries. The poultry industry is an increasingly important segment of food production and contributor to AR. The objective of this study was to evaluate the prevalence, AR patterns and the characterization of relevant resistance genes in Extended Spectrum β-lactamases (ESBL) and AmpC E. coli from large poultry farms in Ecuador. Sampling was performed from June 2013 to July 2014 in 6 slaughterhouses that slaughter broilers from 115 farms totaling 384 flocks. Each sample of collected caeca was streaked onto TBX agar supplemented with cefotaxime (3 mg/l). In total, 176 isolates were analyzed for antimicrobial resistance patterns by the disk diffusion method and for blaCTX-M, blaTEM, blaCMY, blaSHV, blaKPC, and mcr-1 by PCR and sequencing. ESBL and AmpC E. coli were found in 362 flocks (94.3%) from 112 farms (97.4%). We found that 98.3% of the isolates were multi-resistant to antibiotics. Low resistance was observed for ertapenem and nitrofurantoin. The most prevalent ESBL genes were the blaCTX-M (90.9%) blaCTX-M-65, blaCTX-M-55 and blaCTX-M-3 alleles. Most of the AmpC strains presented the blaCMY-2 gene. Three isolates showed the mcr-1 gene. Poultry production systems represent a hotspot for antimicrobial resistance in Ecuador, possibly mediated by the extensive use of antibiotics. Monitoring this sector in national and regional plans of antimicrobial resistance surveillance should therefore be considered.

scholarly journals Characterization of Cobalt Sulfide Thin Films Synthesized from Acidic Chemical Baths

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Tizazu Abza ◽  
Dereje Gelanu Dadi ◽  
Fekadu Gashaw Hone ◽  
Tesfaye Chebelew Meharu ◽  
Gebremeskel Tekle ◽  
...  
Keyword(s):  
Thin Films ◽  
Crystallite Size ◽  
Deposition Time ◽  
Average Crystallite Size ◽  
Cobalt Sulfide ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
Face Centered

Cobalt sulfide thin films were synthesized from acidic chemical baths by varying the deposition time. The powder X-ray diffraction studies indicated that there are hexagonal CoS, face-centered cubic Co3S4, and cubic Co9S8 phases of cobalt sulfide. The crystallite size of the hexagonal CoS phase decreased from 52.8 nm to 22.5 nm and that of the cubic Co9S8 phase increased from 11 nm to 60 nm as the deposition time increased from 2 hrs to 3.5 hrs. The scanning electron microscopic images revealed crack and pinhole free thin films with uniform and smooth background and few large polygonal grains on the surface. The band gap of the cobalt sulfide thin films decreased from 1.75 eV to 1.3 eV as the deposition time increased from 2 hrs to 3.5 hrs. The photoluminescence (PL) spectra of the films confirmed the emission of ultraviolet, violet, and blue lights. The intense PL emission of violet light at 384 nm had red shifted with increasing deposition time that could be resulted from the increase in the average crystallite size. The FTIR spectra of the films indicated the presence of OH, C-O-H, C-O, double sulfide, and Co-S groups. As the deposition time increased, the electrical resistivity of the cobalt sulfide thin films decreased due to the increase in both the crystallite size and the films’ thickness.

Photocatalytic Analysis and Characterization of Zn2SnO4 Nanoparticles Synthesized via Hydrothermal Method with Na2CO3 Mineralizer

2010 ◽  
Vol 97-101 ◽  
pp. 19-22 ◽  
Author(s):  
Yu Shiang Wu ◽  
Wen Ku Chang ◽  
Min Jou
Keyword(s):  
Photocatalytic Activity ◽  
Hydrothermal Process ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
Transmission Electron ◽  
Excellent Photocatalytic Activity ◽  
Face Centered ◽  
Xrd Patterns

Zinc stannate Zn2SnO4 (ZTO) nanoparticles were synthesized via a hydrothermal process utilizing sodium carbonate (Na2CO3) as a weak basic mineralizer. The samples were hydrothermally treated at 150, 200, and 250oC for 48 h. The X-ray diffraction (XRD) patterns show that the highly-crystalline ZTO nanostructure could be formed in a well-dispersed manner for the 250°C sample at a particle size of less than 50 nm. As determined from transmission electron microscopy (TEM) results, ZTO nanoparticles are face-centered cubic single crystals agglomerated together. The Raman spectra results showed that the ZTO nanocrystals have a spinel structure. Furthermore, photocatalytic activity was tested with methylene blue (MB) by UV irradiation. The ZTO synthesized by the 2 M Na2CO3 mineralizer at 250oC demonstrated excellent photocatalytic activity. The ZTO treated three different ways had three distinct UV-Visible absorption curves, which directly influences their corresponding photocatalytic activity.

Synthesis and Characterization of Cobalt-Nickel Nanowires Formed under External Magnetic Field

2015 ◽  
Vol 799-800 ◽  
pp. 120-124 ◽  
Author(s):  
Mary Donnabelle L. Balela ◽  
Lalaine M. Dulin ◽  
Erica A. Garcia ◽  
M. Janelle H. Tica
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hexagonal Close Packed ◽  
Cobalt Nickel ◽  
Nickel Nanowires ◽  
Face Centered

Cobalt-nickel (Co-Ni) nanowires were formed by electroless deposition in ethylene glycol under external magnetic field. The effects of initial Co (II) and Ni (II) concentration on the surface and morphology of the synthesized nanowires were investigated by x-ray diffraction (XRD) and scanning electron microscope (SEM) respectively. An increase in the Co (II) concentration resulted in increase in diameter of the nanowires. However, the length of nanowires was observed to decrease. Higher Co (II) concentration resulted in a mixture of hexagonal close-packed and face-centered cubic Co-Ni nanowires. X-ray diffraction revealed that crystal growth occurred when the nanowires are annealed at 653 K for 10h.

scholarly journals Frequency of Detection ofEscherichia coli,Salmonellaspp., andCampylobacterspp. in the Faeces of Wild Rats (Rattusspp.) in Trinidad and Tobago

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Comfort Nkogwe ◽  
Juliah Raletobana ◽  
Alva Stewart-Johnson ◽  
Sharianne Suepaul ◽  
Abiodun Adesiyun
Keyword(s):  
Antimicrobial Agents ◽  
Diffusion Method ◽  
Disc Diffusion ◽  
Macconkey Agar ◽  
Disc Diffusion Method ◽  
O157 Strain ◽  
E Coli ◽  
Faecal Samples ◽  
Wild Rats

The study was conducted to determine the frequency of isolation ofSalmonella,CampylobacterandE. coliO157 in the faecal samples of rats trapped across the regional corporations in Trinidad and to assess their resistance to antimicrobial agents. A total of 204 rats were trapped for the detection of selected bacteria. Standard methods were used to isolateSalmonella,CampylobacterandE. coliO157. Characterization ofE. coliwas done on sorbitol MacConkey agar to determine non-sorbitol fermentation, blood agar to determine haemolytic and mucoid colonies and by usingE. coliO157 antiserum to determine O157 strain. The disc diffusion method was used to determine resistance to nine antimicrobial agents. Of the 204 rats, 4 (2.0%), 7 (3.4%) and 171 (83.8%) were positive forSalmonellaspp.,Campylobacterspp. andE. coli, respectively. Of the 171 isolates ofE. colitested 0 (0.0%), 25 (14.6%) and 19 (11.1%) were haemolytic, mucoid and non-sorbitol fermenters, respectively. All isolates were negative for the O157 strain. The frequency of resistance to the 9 antimicrobial agents tested was 75% (3 of 4) forSalmonella, 85.7% (6 of 7) ofCampylobacterspp. and 36.3% (62 of 171) forE. coli(;χ2).

Buerger precession camera and overall characterization of thin films and flat-plate crystals

1987 ◽  
Vol 20 (3) ◽  
pp. 210-221 ◽  
Author(s):  
J.-L. Staudenmann ◽  
R. D. Horning ◽  
R. D. Knox
Keyword(s):  
Flat Plate ◽  
Structural Information ◽  
Face Centered Cubic ◽  
Si Substrates ◽  
Bulk Growth ◽  
Face Centered ◽  
Non Destructive ◽  
Growth Methods ◽  
Stacking Disorder

A fast simple and non-destructive method is described to provide qualitative structural information for flat-plate crystals and epitaxically grown films. The technique, based upon the Buerger precession camera, produces an easy-to-interpret photograph of the reciprocal space of all the components at once: substrate, film or buffer layer, and/or superlattice. A wide variety of technologically important examples are used to illustrate the technique: a mixture of CdTe phases on (001) Si, an aluminium layer on a (001) Si substrate, (001) Ge epitaxic layers on (001) Si substrates, three combinations of possible orientations of CdTe epitaxic layers on various substrate types, CdTe/ZnTe and other II–VI superlattices on GaAs substrates. In addition, the precession pictures readily reveal the common [111] face-centered cubic twin fault, or stacking disorder, seen in bulk growth methods. This finding may have severe consequences for the electronic mobility and the feasibility of devices fabricated from these composite systems.

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