Researches Regarding the Improvment of Different Dental Contemporary Composite Materials Structure

2018 ◽  
Vol 69 (7) ◽  
pp. 1774-1778
Author(s):  
Irina Gradinaru ◽  
Leonard Ignat ◽  
Florica Doroftei ◽  
Maurusa Elena Ignat ◽  
Magda Ecaterina Antohe
Keyword(s):  
Silver Nanoparticles ◽  
Organic Matter ◽  
Composite Materials ◽  
Medical Practice ◽  
Structural Changes ◽  
Dental Practice ◽  
Sem Images ◽  
Phase Mixing ◽  
Posterior Area ◽  
Residual Organic Matter

The purpose of this study was to test the structural improving that may be acquired by adding hydroxyapatite microparticles bearing or not silver nanoparticles to three different commercial products commonly used in dental practice. The practical part of this study consisted in the preparation of a common protocol of nine samples resulting from the creation of cavities and their filling similarly to the solving of different clinical situations of carious processes, extracted teeth belonging to both the anterior and the posterior area, with different architectures of the loss of dental substance. Before use, both HA and HA/AgNP have been subjected to calcination in an oven at 6000C for three hours in order to eliminate the residual organic matter. The structural changes have been studied on three types of composites known in the medical practice under the tradenames of Ceram X Duo, Swiss Tec and Herculite XRV Ultra. The structural changes materialized at the level of dentinal component are clearly visible in the SEM images recorded for each starting commercial material. Thus, the addition of HA with high polydispersity (within the range of tens of nanometers and several microns) was effective on lowering the surface rugosity and apparent macro-porosity, while enhancing the phase mixing and component cohesion, but only in the case of Ceram X Duo and Swiss Tec materials. For Herculite XRV Ultra these effects seems to be limited or even reversed, phenomenon that could be explained by the fact that this material already contains nano-fillers, and their concentration tends to saturation.

CHANGES OF MICROPARTICLES AND BACTERIA IN GAPPEI-SYORI JOHKASOU AND RESIDUAL ORGANIC MATTER IN WATER OF THE TREATED WATER TANK

2018 ◽  
Vol 74 (7) ◽  
pp. III_415-III_422
Author(s):  
Yasushi ISHIGURO ◽  
Guangyu CUI ◽  
Tomonari FUJISAWA ◽  
Katsuhito YASUFUKU ◽  
Shinya OKUMURA ◽  
...  
Keyword(s):  
Organic Matter ◽  
Water Tank ◽  
Treated Water ◽  
Residual Organic Matter

Immunization efficacy of ozone-exposed cercariae against subsequent Schistosoma mansoni challenge infection

2011 ◽  
Vol 61 (3) ◽  
pp. 289-301
Author(s):  
Azza H. Mohamed
Keyword(s):  
Schistosoma Mansoni ◽  
Worm Burden ◽  
Structural Changes ◽  
Relative Weight ◽  
Challenge Infection ◽  
Total Leukocyte Count ◽  
Post Challenge ◽  
Igg Antibody ◽  
Sem Images ◽  
Infected Control

AbstractCD1 mice were immunized subcutaneously with 20 ozone-exposed (70μg/ml, 1 minute exposure) Schistosoma mansoni cercariae weekly/three weeks. The efficacy of immunization was assessed 10 weeks post challenge infection by the determination of the worm burden, ova count, oogram, granuloma diameter, IgG reactions against soluble egg antigen (SEA) and tegument structural changes of recovered worms that are immunized. A reduced worm length and a reduction in worm burden were observed in the immunized group as compared to the infected not immunized group. Moreover, no ova were found in liver and intestine from the immunized mice as compared with infected control mice. Also, immunization with ozonated cercariae showed a decrement in the mean relative weight of liver and spleen. Total leukocyte count was increased in the immunized animal as compared to the infected control. The level of total IgG antibody against SEA decreased in immunized mice as compared with the infected control mice. Scanning electron microscope (SEM) images of worms recovered 10 weeks post challenge from the immunized group revealed extensive tegumental destruction. This study underlines the significant role of ozone attenuated cercariae vaccine against S. mansoni infection, which generated specific immunity with a significant level of protection.

In situ and facile synthesis of silver nanoparticles on baby wipes and their applications in catalysis and SERS

RSC Advances ◽  
2016 ◽  
Vol 6 (6) ◽  
pp. 5016-5023 ◽  
Author(s):  
Bharat Baruah
Keyword(s):  
Silver Nanoparticles ◽  
Composite Materials ◽  
Heterogeneous Catalyst ◽  
Facile Synthesis ◽  
Sers Substrates ◽  
Efficient Heterogeneous Catalyst

Silver nanoparticles were immobilized on fibers to create composite materials. The composites are shown to be efficient heterogeneous catalyst with very good recyclability. These composite materials are also proven to be good SERS substrates.

Organic matter induced mobilization of polymer-coated silver nanoparticles from water-saturated sand

2015 ◽  
Vol 529 ◽  
pp. 182-190 ◽  
Author(s):  
Xinyao Yang ◽  
Ziyi Yin ◽  
Fangmin Chen ◽  
Jingjing Hu ◽  
Yuesuo Yang
Keyword(s):  
Silver Nanoparticles ◽  
Organic Matter ◽  
Saturated Sand ◽  
Water Saturated

scholarly journals Improvement of mechanical, thermal and morphostructural properties of SBS thermoplastic elastomer using kaolin and dolomite microparticles with modified surface

2020 ◽  
Author(s):  
Maria Sonmez ◽  
Mircea Juganaru ◽  
Anton Ficai ◽  
Ovidiu Oprea ◽  
Roxana Trusca ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Thermoplastic Elastomer ◽  
Elemental Distribution ◽  
Sem Images ◽  
Strong Stabilization ◽  
Modified Surface ◽  
Styrene Butadiene ◽  
Dsc Curves ◽  
Thermoplastic Rubber

The aim of this paper was to assess the influence of the modification of the surface of dolomite and kaolin with SiO2 and TiO2 precursors, on the block copolymer styrene-butadiene-styrene (SBS) type thermoplastic rubber properties. These composite materials were obtained by compounding SBS with various ratio of powders. Based on the SEM images it can conclude that the powders were homogenously dispersed in to the SBS matrix. The dolomite particles can be clearly identified in the SEM images as particles of 10 micrometers. The samples obtained with modified dolomite have similar morphology. The EDS elemental distribution confirming a good corroboration between the elements of the dolomite, kaolin and titanium or silicon elements. Based on the thermal analysis according to the residual mass, the presence of 20% mineral phase can be confirmed. According to the DSC curves a strong stabilization of the composite appears, because of the presence of the mineral component. According to the physical-mechanical data all the composite materials exhibit improved mechanical properties. Additionally, the modification of the kaolin and/or dolomite bring important improvements in mechanical properties. The samples 13 and 14 exhibit high tensile and tear strength. These composites can be used for various applications, such as, for instance, soles for firefighters' footwear.

scholarly journals Temperature-Driven Hydrocarbon Generation-Expulsion and Structural Transformation of Organic-Rich Shale Assessed by in situ Heating SEM

2021 ◽  
Vol 9 ◽  
Author(s):  
Yuan Yuan ◽  
Jijin Yang
Keyword(s):  
Structural Changes ◽  
Fracture Network ◽  
Reservoir Rock ◽  
Continuous Heating ◽  
Hydrocarbon Generation ◽  
Sem Images ◽  
Cap Rock ◽  
Hydrocarbon Expulsion ◽  
The Relationship

Mud shale can serve as source or cap rock but also as a reservoir rock, and so the development of pores or cracks in shale has become of great interest in recent years. However, prior work using non-identical samples, varying fields of view and non-continuous heating processes has produced varying data. The unique hydrocarbon generation and expulsion characteristics of shale as a source rock and the relationship with the evolution of pores or cracks in the reservoir are thus not well understood. The present work attempted to monitor detailed structural changes during the continuous heating of shale and to establish possible relationships with hydrocarbon generation and expulsion by heating immature shale samples while performing in situ scanning electron microscopy (SEM) imaging and monitoring the chamber vacuum. Samples were heated at 20°C/min from ambient to 700°C with 30 min holds at 100°C intervals during which SEM images were acquired. The SEM chamber vacuum was found to change during sample heating as a consequence of hydrocarbon generation and expulsion. Two episodic hydrocarbon expulsion stages were observed, at 300 and 500°C. As the temperature was increased from ambient to 700°C, samples exhibited consecutive shrinkage, expansion and shrinkage, and the amount of structural change in the vertical bedding direction was greater than that in the bedding direction. At the same time, the opening, closing and subsequent reopening of microcracks was observed. Hydrocarbon generation and expulsion led to the expansion of existing fractures and the opening of new cracks to produce an effective fracture network allowing fluid migration. The combination of high-resolution SEM and a high-temperature heating stage allowed correlation between the evolution of pores or cracks and hydrocarbon generation and expulsion to be examined.

Antimicrobial Activities of Coriander Seed Essential Oil and Silver Nanoparticles

2021 ◽  
Author(s):  
Kadriye Ozlem saygi ◽  
Birgul Kacmaz ◽  
Serdar Gul
Keyword(s):  
Silver Nanoparticles ◽  
Essential Oil ◽  
Bacterial Infections ◽  
Materials Science ◽  
Antimicrobial Properties ◽  
Antimicrobial Activities ◽  
Elemental Distribution ◽  
Sem Images ◽  
X Ray ◽  
Coriander Seed

Abstract Bacterial infections are one of the most serious health problems all over the world, which cause need for the discovery of new drug. Since antibiotic resistance is a major threat to both humans and the environment, there is a need for studies on the antimicrobial properties of different forms of traditionally used plants. Herein, the seeds of coriander were used to isolate essential oil (EO) and to synthesise silver nanoparticles (C-AgNPs). The major oil constituents were characterized by GC-MS as Linalool (79.12%), Camphor (6.16%), γ-Terpinene (2.82%) and α-Pinene (2.67%). The synthesized AgNPs were characterized by UV-Visible spectrophotometry, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), X-ray difraction (XRD) and Fourier Tranmission Infrared (FTIR). The surface plasmon resonance (SPR) of C-AgNPs at 437 nm was recorded on the UV-Vis spectrometer. The spherical and homogenous of AgNPs was presented in SEM images. EDX showed elemental distribution and confirmed AgNPs. A characteristic intense peak was at 3.0 keV. The antibacterial activities of the essential oil and AgNPs form of coriander seed against Staphylococcus aureus ATCC 29213 and Escherichia coli ATCC 25922 bacteria were investigated by broth microdilution test. AgNPs and essential oil of coriander can be expected to provide future opportunities in nanomedicine and materials science. AgNPs can be displayed synergistic antimicrobial effect when used in combination with essential oil.

Evaluating the interaction of biofilms, organic matter and soil structures at the pore scale

2021 ◽  
Author(s):  
Alexander Prechtel ◽  
Simon Zech ◽  
Alice Lieu ◽  
Raphael Schulz ◽  
Nadja Ray
Keyword(s):  
Organic Matter ◽  
Structural Changes ◽  
Effective Diffusivity ◽  
Computational Domain ◽  
Pore Scale ◽  
Gas Phases ◽  
Soil Structures ◽  
Ldg Method ◽  
Conventional Models ◽  
Diffusive Processes

<div class="description js-mathjax"> <p>Key functions of soils, such as permeability or habitat for microorganisms, are determined by structures at the microaggregate scale. The evolution of elemental distributions and dynamic processes can often not be assessed experimentally. So mechanistic models operating at the pore scale are needed.<br />We consider the complex coupling of biological, chemical, and physical processes in a hybrid discrete-continuum modeling approach. It integrates dynamic wetting (liquid) and non-wetting (gas) phases including biofilms, diffusive processes for solutes, mobile bacteria transforming into immobile biomass, and ions which are prescribed by means of partial differential equations. Furthermore the growth of biofilms as, e.g., mucilage exuded by roots, or the distribution of particulate organic matter in the system, is incorporated in a cellular automaton framework (CAM) presented in [1, 2]. It also allows for structural changes of the porous medium itself (see, e.g. [3]). As the evolving computational domain leads to discrete discontinuities, we apply the local discontinuous Galerkin (LDG) method for the transport part. Mathematical upscaling techniques incorporate the information from the pore to the macroscale [1,4].<br />The model is applied for two research questions: We model the incorporation and turnover of particulate OM influencing soil aggregation, including ‘gluing’ hotspots, and show scenarios varying of OM input, turnover, or particle size distribution. <br />Second, we quantify the effective diffusivity on 3D geometries from CT scans of a loamy and a sandy soil. Conventional models cannot account for natural pore geometries and varying phase properties. Upscaling allows also to quantify how root exudates (mucilage) can significantly alter the macroscopic soil hydraulic properties.</p> </div> <div id="field-23"> <p>[1]  Ray, Rupp, Prechtel (2017). AWR (107), 393-404.<br />[2] Rupp, Totsche, Prechtel, Ray (2018). Front. Env. Sci. (6) 96.<br />[3] Zech, Dultz, Guggenberger, Prechtel, Ray (2020). Appl. Clay Sci. 198, 105845.<br />[4] Ray, Rupp, Schulz, Knabner (2018). TPM 124(3), 803-824.</p> </div>

scholarly journals Aging reduces the toxicity of pristine but not sulphidised silver nanoparticles to soil bacteria

2018 ◽  
Vol 5 (11) ◽  
pp. 2618-2630 ◽  
Author(s):  
Carolin L. Schultz ◽  
Joanna Gray ◽  
Rudo A. Verweij ◽  
Martí Busquets-Fité ◽  
Victor Puntes ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Soil Bacteria

Aging of silver nanoparticles shows soluble silver driving toxicity in ISO medium, but not in media containing natural organic matter.

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