scholarly journals Synthesis and Characterization of Some Graphene Oxide Powders Used as Additives in Hydraulic Mortars

2021 ◽  
Vol 11 (23) ◽  
pp. 11330
Author(s):  
Doina Prodan ◽  
Marioara Moldovan ◽  
Gabriel Furtos ◽  
Codruța Saroși ◽  
Miuța Filip ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Antibacterial Effect ◽  
Inhibition Zone ◽  
Infrared Spectrometry ◽  
Bacterial Strains ◽  
Sem Images ◽  
Hydraulic Lime ◽  
Oxide Powders ◽  
Before And After

Various powders of graphene oxide (GO), GO with silver (GO-Ag) and zinc oxide (GO-ZnO) were obtained. The powders were silanized with (3-aminopropyl) triethoxysilane (APTES) aiming to be used, in a future stage, as additives in the hydraulic lime mortars composition. The powders were characterized by Fourier Transform Infrared Spectrometry (FTIR) and Scanning Electron Microscopy (SEM) before and after the silanization process. GO, GO-Ag, GO-Ag-APTES, GO-ZnO and GO-ZnO-APTES powders were also investigated by Thermogravimetric Analysis (TG/DTA) and Ultraviolet–Visible Spectroscopy (UV-Vis). Likewise, the antibacterial effect of powders against five bacterial strains was evaluated. The peaks associated to the functional groups from GO, GO-APTES, GO-Ag, GO-Ag-APTES, GO-ZnO and GO-ZnO-APTES powders were identified by FTIR analysis. The mass losses of powders, analyzed by TG/DTA were lower than those recorded for GO. By UV-VIS analysis, maxima corresponding to the electronic π-π * and n-π * transitions were recorded. SEM images highlighted the lamellar and layered structure of GO, but also the presence of Ag and Zn nanoparticles on the surface of graphene sheets. All these results confirm the presence of Ag/ZnO/APTES on the GO. The antibacterial effect evaluated by recording the diameter of the inhibition zone ranged between 12–22 mm.

scholarly journals A rapidly-dissolving silica-silver bioactive glass for cariostatic applications

2021 ◽  
Author(s):  
Saad Arshad
Keyword(s):  
Oral Cavity ◽  
Antibacterial Effect ◽  
Surface Hardness ◽  
Tris Buffer ◽  
Bacterial Strains ◽  
Buffer Solution ◽  
Solution Ph ◽  
Before And After ◽  
Knoop Microhardness ◽  
Tris Buffer Solution

In this study, bioactive glasses were designed for the purposes of reducing the incidence of dental caries and lesion formation by supplying the teeth with therapeutic ions which may support remineralization and provide an antibacterial effect against oral cavity bacteria. Three glasses were synthesised through the melt quench method: Si-Control (SiO2-CaO-P2O5-Na2O), Si-02 and Si-05, where 0.2% and 0.5% Ag2O were substituted, respectively, for SiO2 in the control glass. The glasses were then ground, characterized and dissolved in tris buffer solution (pH=7.30) for 6, 12 and 24 hours, with the pH rise of the solution being recorded (7.48 for Si-Control, and 7.66 for both Si-02 and Si-05 after 24 hours) and the ions that were released into the tris buffer solution quantified. Samples of each glass were subsequently embedded into non-fluoridated toothpaste and samples of the paste were used to brush resin-mounted lamb molars after a 1.0M HCl overnight demineralization challenge. Knoop microhardness measurements were recorded before and after brushing to determine the presence of remineralization on the surface of the teeth (Percent Surface Hardness Loss of 37%, 35% and 34% for Si-Control, Si-02 and Si-05 respectively after 24 hours). Four oral cavity bacterial strains were isolated through swabs of the inner cheek, gums and teeth surfaces of three volunteers, and placed on agar discs. 0.5g of each glass were placed onto the discs and the resultant inhibition zones were measured after 6, 12 and 24 hours. Si-05 consistently performed better than Si-02 on all strains and timeframes, while Si-Control exhibited no antibacterial effect at any time point.

scholarly journals A rapidly-dissolving silica-silver bioactive glass for cariostatic applications

2021 ◽  
Author(s):  
Saad Arshad
Keyword(s):  
Oral Cavity ◽  
Antibacterial Effect ◽  
Surface Hardness ◽  
Tris Buffer ◽  
Bacterial Strains ◽  
Buffer Solution ◽  
Solution Ph ◽  
Before And After ◽  
Knoop Microhardness ◽  
Tris Buffer Solution

In this study, bioactive glasses were designed for the purposes of reducing the incidence of dental caries and lesion formation by supplying the teeth with therapeutic ions which may support remineralization and provide an antibacterial effect against oral cavity bacteria. Three glasses were synthesised through the melt quench method: Si-Control (SiO2-CaO-P2O5-Na2O), Si-02 and Si-05, where 0.2% and 0.5% Ag2O were substituted, respectively, for SiO2 in the control glass. The glasses were then ground, characterized and dissolved in tris buffer solution (pH=7.30) for 6, 12 and 24 hours, with the pH rise of the solution being recorded (7.48 for Si-Control, and 7.66 for both Si-02 and Si-05 after 24 hours) and the ions that were released into the tris buffer solution quantified. Samples of each glass were subsequently embedded into non-fluoridated toothpaste and samples of the paste were used to brush resin-mounted lamb molars after a 1.0M HCl overnight demineralization challenge. Knoop microhardness measurements were recorded before and after brushing to determine the presence of remineralization on the surface of the teeth (Percent Surface Hardness Loss of 37%, 35% and 34% for Si-Control, Si-02 and Si-05 respectively after 24 hours). Four oral cavity bacterial strains were isolated through swabs of the inner cheek, gums and teeth surfaces of three volunteers, and placed on agar discs. 0.5g of each glass were placed onto the discs and the resultant inhibition zones were measured after 6, 12 and 24 hours. Si-05 consistently performed better than Si-02 on all strains and timeframes, while Si-Control exhibited no antibacterial effect at any time point.

The Synthesis and Characterization of the Graphene Oxide Covalent Modified Phenolic Resin Nanocomposites

2011 ◽  
Vol 327 ◽  
pp. 115-119 ◽  
Author(s):  
Duo Wang ◽  
Jie Gao ◽  
Wei Fang Xu ◽  
Feng Bao ◽  
Rui Ma ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Phenolic Resin ◽  
Synthesis And Characterization ◽  
Infrared Spectrometry ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Hummers Method ◽  
Modified Hummers Method ◽  
Thermal Stability Of

Graphene oxide (GO) was made by a modified Hummers method. Graphene oxide modified phenolic resin nanocomposites (GO/PF) were prepared by Steglich esterification, catalyzed by dicyclohexyl carbodiimide and 4-dimethylaminopyridine. The composites were characterized by Fourier transform infrared spectrometry, differential scanning calorimetry, X-ray powder diffraction, and scanning electron microscopy. The result revealed that the graphene oxide was absolutely exfoliated and covalent linked GO/PF composite was obtained. The thermal stability of PF is remarkably improved by modification with GO.

scholarly journals Rapidly-Dissolving silver-containing bioactive glasses for cariostatic applications

2021 ◽  
Author(s):  
Omar Rodríguez ◽  
Adel M.F. Alhalawani ◽  
Saad Arshad ◽  
Mark R. Towler
Keyword(s):  
Silver Oxide ◽  
Surface Hardness ◽  
Inhibition Zone ◽  
Bacterial Strains ◽  
Buffer Solution ◽  
Solution Ph ◽  
Before And After ◽  
Resultant Solution ◽  
Knoop Microhardness

A novel bioactive glass series containing incremental amounts of silver oxide was synthesized, ground down, and subsequently incorporated into a dentifrice for the purpose of reducing the incidence of dental caries and lesion formation. Three glasses were synthesized using the melt quench route: Si-Control (70SiO2–12CaO–3P2O5–15Na2O, mol %), Si-02 and Si-05, where 0.2 and 0.5 mol % Ag2O were substituted, respectively, for SiO2 in Si-Control. The glasses were then ground, sieved, characterized, and dissolved in Tris buffer solution (pH = 7.30) for 6, 12, and 24 h, with the pH of the resultant solution being recorded and the ions that were released into solution quantified. Samples of each glass were subsequently embedded into a non-fluoridated, commercially available toothpaste which was then used to brush resin-mounted lamb molars which, up to the point of testing, had been stored in a 1.0 M HCl solution. Knoop microhardness measurements of the molars were recorded before and after brushing to determine the presence of remineralization on the surface of the teeth (surface hardness loss of 37%, 35%, and 34% for Si-Control, Si-02 and Si-05, respectively, after 24 h). Four oral cavity bacterial strains were isolated through swabs of the inner cheek, gums, and teeth surfaces of three volunteers, and placed on agar discs. Of each glass, 0.5 g was placed onto the discs, and the resultant inhibition zones were measured after 6, 12, and 24 h. Si-05 performed better than Si-02 on two strains after 24 h, while exhibiting similar behavior for the remaining two strains after 24 h; the largest inhibition zone measured was 2.8 mm, for Si-05 after 12 h. Si-Control exhibited no antibacterial effect at any time point, providing evidence for the role of silver oxide as the antibacterial component of these glasses.

The Surface Chemistry Characterization of Pyrite, Sphalerite and Molybdenite after Bioleaching

2017 ◽  
Vol 262 ◽  
pp. 487-491 ◽  
Author(s):  
Sina Ghassa ◽  
Hadi Abdollahi ◽  
Mahdi Gharabaghi ◽  
Saeed Chehreh Chelgani ◽  
Mohammad Jafari
Keyword(s):  
Surface Chemistry ◽  
Dissolution Kinetics ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Chemical Leaching ◽  
Characterization Methods ◽  
X Ray ◽  
Ash Layer ◽  
Before And After

The mineral surface chemistry characterization is essential to describe the dissolution kinetics in leaching and bioleaching. Five different methods, including X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopy, have been applied to study the surface chemistry changes during pyrite, sphalerite and molybdenite bioleaching. The surface characterizations have been done for samples before and after biological and chemical leaching. The SEM images illustrated that the minerals surfaces were smooth before processing, while they covered with an ash layer after biological treatment. Although EDS analysis and Raman spectrum demonstrated the potassium jarosite formation on the pyrite surface during bioleaching, the formation of jarosite layer did not occur on the sphalerite surfaces during bioleaching. On the other hand, a sulfur layer formation on the sphalerite surface was confirmed by mentioned characterization methods. Finally, according to the XRD and EDS spectrum the molybdenite surface had been covered both with sulfur and jarosite.

Wafer Bumping and Characterizations of Fine-Pitch Lead-Free Solder Microbumps on 12” (300mm) wafer for 3D IC Integration

2011 ◽  
Vol 2011 (1) ◽  
pp. 000650-000656
Author(s):  
J. H. Lau ◽  
P-J Tzeng ◽  
C-K Lee ◽  
C-J Zhan ◽  
M-J Dai ◽  
...  
Keyword(s):  
Cross Sections ◽  
Lead Free ◽  
Lead Free Solder ◽  
Sem Images ◽  
3D Ic ◽  
Fine Pitch ◽  
Solder Bumps ◽  
Before And After ◽  
Free Solder

In this study, the wafer bumping and characterization of fine-pitch lead-free solder microbumps on 300mm wafer for 3D IC integration are investigated. Emphasis is placed on the Cu-plating solutions (conformal and bottom-up). Also, the amount of Cu and solder (Sn) volumes is examined. Furthermore, characterizations such as shearing test and aging of the microbumps are provided and cross sections/SEM images of the microbumps before and after test are discussed. Finally, the process windows of applying the conventional electroplating wafer bumping method of the ordinary solder bumps to the microbumps are also presented.

scholarly journals Rapidly-Dissolving silver-containing bioactive glasses for cariostatic applications

2021 ◽  
Author(s):  
Omar Rodríguez ◽  
Adel M.F. Alhalawani ◽  
Saad Arshad ◽  
Mark R. Towler
Keyword(s):  
Silver Oxide ◽  
Surface Hardness ◽  
Inhibition Zone ◽  
Bacterial Strains ◽  
Buffer Solution ◽  
Solution Ph ◽  
Before And After ◽  
Resultant Solution ◽  
Knoop Microhardness

A novel bioactive glass series containing incremental amounts of silver oxide was synthesized, ground down, and subsequently incorporated into a dentifrice for the purpose of reducing the incidence of dental caries and lesion formation. Three glasses were synthesized using the melt quench route: Si-Control (70SiO2–12CaO–3P2O5–15Na2O, mol %), Si-02 and Si-05, where 0.2 and 0.5 mol % Ag2O were substituted, respectively, for SiO2 in Si-Control. The glasses were then ground, sieved, characterized, and dissolved in Tris buffer solution (pH = 7.30) for 6, 12, and 24 h, with the pH of the resultant solution being recorded and the ions that were released into solution quantified. Samples of each glass were subsequently embedded into a non-fluoridated, commercially available toothpaste which was then used to brush resin-mounted lamb molars which, up to the point of testing, had been stored in a 1.0 M HCl solution. Knoop microhardness measurements of the molars were recorded before and after brushing to determine the presence of remineralization on the surface of the teeth (surface hardness loss of 37%, 35%, and 34% for Si-Control, Si-02 and Si-05, respectively, after 24 h). Four oral cavity bacterial strains were isolated through swabs of the inner cheek, gums, and teeth surfaces of three volunteers, and placed on agar discs. Of each glass, 0.5 g was placed onto the discs, and the resultant inhibition zones were measured after 6, 12, and 24 h. Si-05 performed better than Si-02 on two strains after 24 h, while exhibiting similar behavior for the remaining two strains after 24 h; the largest inhibition zone measured was 2.8 mm, for Si-05 after 12 h. Si-Control exhibited no antibacterial effect at any time point, providing evidence for the role of silver oxide as the antibacterial component of these glasses.

scholarly journals Antibacterial Effect of Hydroalcoholic Extract ofPunica granatumLinn. Petal on Common Oral Microorganisms

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Farnaz Hajifattahi ◽  
Elham Moravej-Salehi ◽  
Maryam Taheri ◽  
Arash Mahboubi ◽  
Mohammad Kamalinejad
Keyword(s):  
Growth Inhibition ◽  
Antibacterial Effect ◽  
Brain Heart Infusion ◽  
Inhibition Zone ◽  
Maximum Effect ◽  
Streptococcus Sobrinus ◽  
Bacterial Strains ◽  
Hydroalcoholic Extract ◽  
Growth Inhibition Zone

Objectives. This study aimed to assess the effect of hydroalcoholic extract ofPunica granatumLinn. (P. granatum) petal onStreptococcus sanguinis,Streptococcus mutans,Streptococcus salivarius,Streptococcus sobrinus,andEnterococcus faecalis.Materials and Methods. In this in vitro study,P. granatumextract was prepared using powdered petals and water-ethanol solvent. Antibacterial effect of the extract, chlorhexidine (CHX), and ampicillin was evaluated on brain heart infusion agar (BHIA) using the cup-plate method. By assessing the diameter of the growth inhibition zone, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the extract were determined for the above-mentioned bacteria.Results. Hydroalcoholic extract ofP. granatumpetal had inhibitory effects on the proliferation of all five bacterial strains with maximum effect onS. mutanswith MIC and MBC of 3.9 mg/mL. The largest growth inhibition zone diameter belonged toS. sanguinisand the smallest toE. faecalis. Ampicillin and CHX had the greatest inhibitory effect onS. sanguinis.Conclusions. Hydroalcoholic extract ofP. granatumhad a significant antibacterial effect on common oral bacterial pathogens with maximum effect onS. mutans, which is the main microorganism responsible for dental plaque and caries.

scholarly journals Chemical composition and antibacterial effect of Smyrnium olusatrum L. Fruit Essential Oil

2020 ◽  
Vol 10 (6) ◽  
pp. 577
Author(s):  
Saida Cherif Hamida ◽  
Imane Zalegh ◽  
Fairouz Saidi ◽  
Nabahat Benmanssour ◽  
M. Carmen González-Mas ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Essential Oil ◽  
Inhibitory Concentration ◽  
Antibacterial Effect ◽  
Biological Activities ◽  
Inhibition Zone ◽  
Bacterial Strains ◽  
Gram Positive Bacteria ◽  
Therapeutic Properties

The plants of the <em>Apiaceae</em> family are mainly used for food purposes and their multiple therapeutic properties and biological activities. This study aims to determine the chemical composition of Essential Oil (EO) of the fruits of <em>Smyrnium olusatrum</em> L. obtained by hydrodistillation in Clevenger-type apparatus. GC/MS analyzed the EO and the antibacterial activity was evaluated against clinical bacterial strains by two complementary methods (Disc diffusion and micro-atmosphere) and determination of Minimal Inhibitory Concentration (MIC). The results of chemical composition show that the EO is dominated by hydrocarbon monoterpenes (55,95%). The antibacterial effect shows that Gram-positive bacteria are the most sensitive to the inhibitory action of EO with inhibition zone diameters (DZI) ranging from 18 to 20 mm for <em>Staphylococcus aureus</em> and <em>Streptococcus faecium</em> strains. The same results were reported with the micro-atmosphere

scholarly journals Analysis Gunshot Residue (GSR) – Reconstruction of Crime Scenes

2017 ◽  
Vol 2 (1) ◽  
Keyword(s):  
Particle Distribution ◽  
Secondary Ion Mass Spectrometry ◽  
Sem Images ◽  
Tof Sims ◽  
Before And After ◽  
Respective Surface ◽  
Secondary Ion ◽  
Molecular Nature ◽  
Bullet Hole

GSR particles from the surroundings of bullet hole have been characterized as a function of primer type and particle distribution. SEM images were used to verify size and shape of the GSR particles and EDS to verify the elemental composition in a single particle. The same specimens are further subjected toTime of Flight Secondary Ion Mass Spectrometry (ToF SIMS) with a view to identify the respective surface chemistry, molecular nature and molecular mass of the GSR particles. Both inorganic and organic components of GSR in the elemental and combined form can be identified using SIMS.Secondary ion mass spectrum and the image analysis are carried out for selected particles. The mass peaks of oxides of lead, barium and antimony apart from the elemental masses are found. The combination of Pb/Ba/Sb and their oxides in a particular particle specifically establish the characteristics of a typical GSR particle. Molecular imaging and the distribution of the components in the GSR particle before and after sputtering are studied. Lead and its oxide are more concentrated in the surface of the particle compared to Ba and Sb. It is evident that SIMS can detect whether the components are either in the elemental or a compound form or a combination of both. The results of ToF SIMS clearly establish the feasibility of utilizing ToF SIMS as a tool for direct characterization of GSR from environmental polluted particles of the same nature for forensic applications.

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