scholarly journals Synthesis, Characterization and Antibacterial Activity of Ag/PVA Nanocomposite

2012 ◽  
Vol 5 (1) ◽  
pp. 151-160 ◽  
Author(s):  
H. H. Saleh ◽  
D. E. El-hadedy ◽  
G. A. Meligi ◽  
T. A. Afify
Keyword(s):  
Antibacterial Activity ◽  
Ag Nanoparticles ◽  
Pathogenic Bacteria ◽  
Pharmaceutical Products ◽  
Poly Vinyl Alcohol ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
Transmission Electron ◽  
Infection Treatment

Synthesis and characterization of Ag/PVA nanocomposite and comparison of its anti-bacterial activity with bacteriocin (nisin) for some pathogenic bacteria was carried out. Applications of the bacteriocin include dental care products, pharmaceutical products such as stomach ulcers, colon infection treatment and potential birth control. Ag/PVA nanocomposite was prepared by in situ reduction method, in which silver nitrate, gamma irradiation and poly(vinyl alcohol) (PVA) act as precursor, reductant and stabilizer, respectively. The synthesized Ag nanoparticles (Ag-Nps) have potential antibacterial activity toward both Gram-positive and Gram-negative bacteria. Further studies by X-ray diffraction (XRD) and transmission electron microscopy (TEM) have demonstrated the structure and the distribution of Ag nanoparticles caped within PVA polymer chain.© 2013 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v5i1.11828        J. Sci. Res. 5 (1), 151-160 (2013)

Antimicrobial Activity of O-Carboxymethyl Chitosan Nanofibers Containing Silver Nanoparticles Synthesized by Green Method

2016 ◽  
Vol 40 ◽  
pp. 136-145 ◽  
Author(s):  
Metwally Ezzat ◽  
Mohammed Ghanim ◽  
Hassan Nageh ◽  
Ahmed H. Hassanin ◽  
Ahmed Abdel-Moneim
Keyword(s):  
Antibacterial Activity ◽  
Wound Dressing ◽  
Pathogenic Bacteria ◽  
Reaction Times ◽  
Carboxymethyl Chitosan ◽  
Diffusion Method ◽  
Ag Nps ◽  
High Antibacterial Activity ◽  
Transmission Electron ◽  
Bacteria And Fungi

New green synthesis of Ag-nanoparticles (Ag-NPs) using O-Carboxymethyl Chitosan (O-CMCs) as stabilizing agent and ascorbic acid as reducing agent was achieved. The reaction was carried out in an autoclave at a pressure of 0.12 MPa and a temperature of 120°C at varying concentrations of solution precursors and different reaction times. The size, shape and structure of Ag-NPs were measured using transmission electron microscope (TEM), X-Ray Diffraction (XRD), FT-IR and UV spectrophotometers. The Ag-NPs stabilized in O-CMCs were blended with polyvinyl alcohol (PVA) polymer solution and then electrospun to produce wound dressing nanofibers with high antibacterial activity. The morphological study of O-CMCs/ PVA/Ag-NPs nanofiber membranes was characterized using SEM. Finally, the release behavior of Ag-NPs from these nanofibers was examined and the antibacterial activity was measured against some skin pathogenic bacteria and fungi using the agar diffusion method. The newly developed membranes show a unique antibacterial activity against the tested strains and were presented as promising active wound dressing materials in medical applications.

scholarly journals Liver Tissue Regeneration using Nano Silver impregnated Sodium Alginate/PVA Composite Nanofibres

2020 ◽  
Vol 2 (1) ◽  
pp. 16-21 ◽  
Author(s):  
Manikandan G ◽  
Yuvashree M ◽  
Sangeetha A ◽  
Bhuvana K P ◽  
Sanjay K Nayak
Keyword(s):  
Antibacterial Activity ◽  
Sodium Alginate ◽  
Ag Nanoparticles ◽  
Liver Tissue ◽  
Average Particle Size ◽  
Antibacterial Properties ◽  
Poly Vinyl Alcohol ◽  
Average Particle ◽  
Ag Nps

Liver regeneration is a highly organized tissue regrowth process and is the most important reaction of the injured liver. The present study endeavors towards the preparation and characterization of nanoporous Sodium Alginate (SA)/ Poly Vinyl Alcohol (PVA) composite, nanofibrous scaffolds coated with silver (Ag) nanoparticles for hepatocellular regeneration.  Chitosan based Silver nanoparticles possess high antibacterial activity has been preferred in the scaffold preparation to improve the antibacterial properties. The structural characterization of Ag Nanoparticles revealed the amorphous nature with an average particle size of 300 nm. Nanofibres (Scaffolds) were prepared by electrospinning SA/PVA solution at a voltage of 18-25 kV and Ag NPs were coated on it for antibacterial activity. Invitro studies denoted the growth of nitro compounds, amides and collagen which are the major constituents of liver tissue.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Epitaxy and texture analysis of Bi-Sr-Ca-Cu-O thin films on (100) MgO using Transmission Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 68-69
Author(s):  
J. T. Sizemore ◽  
D. G. Schlom ◽  
Z. J. Chen ◽  
J. N. Eckstein ◽  
I. Bozovic ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Critical Currents ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Cell Axis ◽  
Transmission Electron ◽  
Synthesis Procedure

Investigators observe large critical currents for superconducting thin films deposited epitaxially on single crystal substrates. The orientation of these films is often characterized by specifying the unit cell axis that is perpendicular to the substrate. This omits specifying the orientation of the other unit cell axes and grain boundary angles between grains of the thin film. Misorientation between grains of YBa2Cu3O7−δ decreases the critical current, even in those films that are c axis oriented. We presume that these results are similar for bismuth based superconductors and report the epitaxial orientations and textures observed in such films.Thin films of nominally Bi2Sr2CaCu2Ox were deposited on MgO using molecular beam epitaxy (MBE). These films were in situ grown (during growth oxygen was incorporated and the films were not oxygen post-annealed) and shuttering was used to encourage c axis growth. Other papers report the details of the synthesis procedure. The films were characterized using x-ray diffraction (XRD) and transmission electron microscopy (TEM).

Devitrification products of rapidly solidified Ni-Nb amorphous alloys.

1990 ◽  
Vol 48 (4) ◽  
pp. 950-951
Author(s):  
G. A. Bertero ◽  
W.H. Hofmeister ◽  
N.D. Evans ◽  
J.E. Wittig ◽  
R.J. Bayuzick
Keyword(s):  
Electron Microscopy ◽  
Amorphous Structure ◽  
Sulphuric Acid Solution ◽  
X Ray Diffraction ◽  
High Fracture ◽  
Transmission Electron ◽  
Xrd Techniques ◽  
Rapidly Solidified ◽  
Electromagnetically Levitated

Rapid solidification of Ni-Nb alloys promotes the formation of amorphous structure. Preliminary results indicate promising elastic properties and high fracture strength for the metallic glass. Knowledge of the thermal stability of the amorphus alloy and the changes in properties with temperature is therefore of prime importance. In this work rapidly solidified Ni-Nb alloys were analyzed with transmission electron microscopy (TEM) during in-situ heating experiments and after isothermal annealing of bulk samples. Differential thermal analysis (DTA), scanning electron microscopy (SEM) and x-ray diffraction (XRD) techniques were also used to characterize both the solidification and devitrification sequences.Samples of Ni-44 at.% Nb were electromagnetically levitated, melted, and rapidly solidified by splatquenching between two copper chill plates. The resulting samples were 100 to 200 μm thick discs of 2 to 3 cm diameter. TEM specimens were either ion-milled or alternatively electropolished in a methanol-10% sulphuric acid solution at 20 V and −40°C.

scholarly journals Microstructure and properties of nano-laminated Y3Si2C2 ceramics fabricated via in situ reaction by spark plasma sintering

2021 ◽  
Vol 10 (3) ◽  
pp. 578-586
Author(s):  
Lin-Kun Shi ◽  
Xiaobing Zhou ◽  
Jian-Qing Dai ◽  
Ke Chen ◽  
Zhengren Huang ◽  
...  
Keyword(s):  
Spark Plasma Sintering ◽  
Atomic Scale ◽  
Max Phase ◽  
X Ray Diffraction ◽  
Selected Area Electron Diffraction ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Spark Plasma ◽  
Diffraction Patterns

AbstractA nano-laminated Y3Si2C2 ceramic material was successfully synthesized via an in situ reaction between YH2 and SiC using spark plasma sintering technology. A MAX phase-like ternary layered structure of Y3Si2C2 was observed at the atomic-scale by high resolution transmission electron microscopy. The lattice parameters calculated from both X-ray diffraction and selected area electron diffraction patterns are in good agreement with the reported theoretical results. The nano-laminated fracture of kink boundaries, delamination, and slipping were observed at the tip of the Vickers indents. The elastic modulus and Vickers hardness of Y3Si2C2 ceramics (with 5.5 wt% Y2O3) sintered at 1500 °C were 156 and 6.4 GPa, respectively. The corresponding values of thermal and electrical conductivity were 13.7 W·m-1·K-1 and 6.3×105 S·m-1, respectively.

Photoluminescence Enhancement of CdS Nanocrystals Fabricated on Dithiocarbamate Functionalized PET Substrates

2012 ◽  
Vol 512-515 ◽  
pp. 1511-1515
Author(s):  
Chun Lin Zhao ◽  
Li Xing ◽  
Xiao Hong Liang ◽  
Jun Hui Xiang ◽  
Fu Shi Zhang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Hexagonal Structure ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Cds Nanocrystals ◽  
Morphological Studies ◽  
Transmission Electron

Cadmium sulfide (CdS) nanocrystals (NCs) were self-assembled and in-situ immobilized on the dithiocarbamate (DTCs)-functionalized polyethylene glycol terephthalate (PET) substrates between the organic (carbon disulfide diffused in n-hexane) –aqueous (ethylenediamine and Cd2+ dissolved in water) interface at room temperature. Powder X-ray diffraction measurement revealed the hexagonal structure of CdS nanocrystals. Morphological studies performed by scanning electron microscopy (SEM) and high-resolution transmission electron microscope (HRTEM) showed the island-like structure of CdS nanocrystals on PET substrates, as well as energy-dispersive X-ray spectroscopy (EDS) confirmed the stoichiometries of CdS nanocrystals. The optical properties of DTCs modified CdS nanocrystals were thoroughly investigated by ultraviolet-visible absorption spectroscopy (UV-vis) and fluorescence spectroscopy. The as-prepared DTCs present intrinsic hydrophobicity and strong affinity for CdS nanocrystals.

scholarly journals Size Control of Synthesized Silver Nanoparticles by Simultaneous Chemical Reduction and Laser Fragmentation in Origanum majorana Extract: Antibacterial Application

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2326
Author(s):  
Entesar Ali Ganash ◽  
Reem Mohammad Altuwirqi
Keyword(s):  
Silver Nanoparticles ◽  
Irradiation Time ◽  
Chemical Reduction ◽  
Size Control ◽  
Reduction Process ◽  
Laser Wavelength ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
Transmission Electron ◽  
Origanum Majorana

In this work, silver nanoparticles (Ag NPs) were synthesized using a chemical reduction approach and a pulsed laser fragmentation in liquid (PLFL) technique, simultaneously. A laser wavelength of 532 nm was focused on the as produced Ag NPs, suspended in an Origanum majorana extract solution, with the aim of controlling their size. The effect of liquid medium concentration and irradiation time on the properties of the fabricated NPs was studied. While the X-ray diffraction (XRD) pattern confirmed the existence of Ag NPs, the UV–Vis spectrophotometry showed a significant absorption peak at about 420 nm, which is attributed to the characteristic surface plasmon resonance (SPR) peak of the obtained Ag NPs. By increasing the irradiation time and the Origanum majora extract concentration, the SPR peak shifted toward a shorter wavelength. This shift indicates a reduction in the NPs’ size. The effect of PLFL on size reduction was clearly revealed from the transmission electron microscopy images. The PLFL technique, depending on experimental parameters, reduced the size of the obtained Ag NPs to less than 10 nm. The mean zeta potential of the fabricated Ag NPs was found to be greater than −30 mV, signifying their stability. The Ag NPs were also found to effectively inhibit bacterial activity. The PLFL technique has proved to be a powerful method for controlling the size of NPs when it is simultaneously associated with a chemical reduction process.

scholarly journals Fracture in Bulk Amorphous Alloys

1998 ◽  
Vol 554 ◽  
Author(s):  
J. A. Horton ◽  
J. L. Wright ◽  
J. H. Schneibel
Keyword(s):  
Crack Propagation ◽  
Crack Growth ◽  
Shear Bands ◽  
Bulk Amorphous Alloy ◽  
In Situ Tem ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Crack Tips ◽  
Temperature Fracture

AbstractThe fracture behavior of a Zr-based bulk amorphous alloy, Zr-10 Al-5 Ti-17.9 Cu-14.6Ni (at.%), was examined by transmission electron microscopy (TEM) and x-ray diffraction forany evidence of crystallization preceding crack propagation. No evidence for crystallizationwas found in shear bands in compression specimens or at the fracture surface in tensile specimens.In- situ TEM deformation experiments were performed to more closely examine actualcrack tip regions. During the in-situ deformation experiment, controlled crack growth occurredto the point where the specimen was approximately 20 μm thick at which point uncontrolledcrack growth occurred. No evidence of any crystallization was found at the crack tips or thecrack flanks. Subsequent scanning microscope examination showed that the uncontrolledcrack growth region exhibited ridges and veins that appeared to have resulted from melting. Performing the deformations, both bulk and in-situ TEM, at liquid nitrogen temperatures (LN2) resulted in an increase in the amount of controlled crack growth. The surface roughness of the bulk regions fractured at LN2 temperatures corresponded with the roughness of the crack propagation observed during the in-situ TEM experiment, suggesting that the smooth-appearing room temperature fracture surfaces may also be a result of localized melting.

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