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360 KiB

Open AccessArticle

Calcium Phosphate Bone Cements Including Sugar Surfactants: Part One—Porosity, Setting Times and Compressive Strength

by Ariane Bercier, Stéphane Gonçalves, Olivier Lignon and Juliette Fitremann

Materials 2010, 3(10), 4695-4709; https://doi.org/10.3390/ma3104695 - 30 Sep 2010

Cited by 14 | Viewed by 10363

Addition of sugar surfactants, sucrose fatty acid esters and alkylpolyglucosides, to calcium phosphate cement designed for bone reconstruction is described. Thanks to their surface activity and through their adsorption at the surface of the calcium phosphate particles, they both induced a strong increase [...] Read more.

Addition of sugar surfactants, sucrose fatty acid esters and alkylpolyglucosides, to calcium phosphate cement designed for bone reconstruction is described. Thanks to their surface activity and through their adsorption at the surface of the calcium phosphate particles, they both induced a strong increase in the porosity (quantified by Image Analysis) and brought a very good workability. Other properties typically studied for these cements are reported, including setting times, compressive strength, cohesion in water, and effect of sterilization on these properties. The whole study brought good insight in the interest of adding these mild surfactants to improve several properties of the calcium phosphate cement, without impairing their function. Full article

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346 KiB

Open AccessArticle

Effect of Temperature on Isolation and Characterization of Hydroxyapatite from Tuna (Thunnus obesus) Bone

by Jayachandran Venkatesan and Se Kwon Kim

Materials 2010, 3(10), 4761-4772; https://doi.org/10.3390/ma3104761 - 15 Oct 2010

Cited by 114 | Viewed by 10997

Abstract

The effect of temperature on isolation and characterization of hydroxyapatite (HAp) from tuna bone was evaluated at different temperatures ranging from 200 °C to 1200 °C. The calcined bones were characterized by thermo gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction [...] Read more.

The effect of temperature on isolation and characterization of hydroxyapatite (HAp) from tuna bone was evaluated at different temperatures ranging from 200 °C to 1200 °C. The calcined bones were characterized by thermo gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX) and cytotoxicity assay. The FTIR and TGA results revealed the presence of inorganic and organic matrices in raw bone and a preserved carbonated group in the derived HAp. The XRD results of the derived HAp were coherent with the Joint Committee on Powder Diffraction Standards (JCPDS-09-0432/1996) data. In addition, FE-SEM results revealed the formation of nanostructured HAp (80–300 nm) at 600 °C and crystal agglomeration was observed with an increase in temperature. The calcium to phosphorous weight ratio was determined by EDX results of treated bones. Derived HAp with various crystal sizes had no cytotoxicity on the MG 63 cell line. Based on the analysis, we conclude that varying the isolation temperature between 600–900 °C has tremendous impact on the production of HAp from Thunnus obesus with required properties. Full article

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439 KiB

Open AccessArticle

Postfunctionalization of Alkyne-Linked Conjugated Carbazole Polymer by Thermal Addition Reaction of Tetracyanoethylene

by Tsuyoshi Michinobu and Hiroyuki Fujita

Materials 2010, 3(10), 4773-4783; https://doi.org/10.3390/ma3104773 - 15 Oct 2010

Cited by 21 | Viewed by 10897

Abstract

The postfunctionalization of the main chain alkyne moieties of carbazole containing poly(arylenebutadiynylene)s was attempted by using a high yielding addition reaction between electron rich alkynes and a strong acceptor molecule, tetracyanoethylene (TCNE). After successful postfunctionalization, the polymer band gap decreased due to the [...] Read more.

The postfunctionalization of the main chain alkyne moieties of carbazole containing poly(arylenebutadiynylene)s was attempted by using a high yielding addition reaction between electron rich alkynes and a strong acceptor molecule, tetracyanoethylene (TCNE). After successful postfunctionalization, the polymer band gap decreased due to the intramolecular donor-acceptor interactions. The resulting donor-acceptor alternating polymer showed a very broad charge-transfer band in the visible region as well as redox activities in both anodic and cathodic directions. The optical band gap showed good agreement with the electrochemical band gap. Furthermore, the thermal stability was enhanced after postfunctionalization. These features of the donor-acceptor alternating polymer are expected to be useful for high performance activities in organic solar cell applications. Full article

(This article belongs to the Special Issue Solar Energy Materials)

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460 KiB

Open AccessReview

Phosphorus-based Flame Retardancy Mechanisms—Old Hat or a Starting Point for Future Development?

by Bernhard Schartel

Materials 2010, 3(10), 4710-4745; https://doi.org/10.3390/ma3104710 - 30 Sep 2010

Cited by 476 | Viewed by 20877

Abstract

Different kinds of additive and reactive flame retardants containing phosphorus are increasingly successful as halogen-free alternatives for various polymeric materials and applications. Phosphorus can act in the condensed phase by enhancing charring, yielding intumescence, or through inorganic glass formation; and in the gas [...] Read more.

Different kinds of additive and reactive flame retardants containing phosphorus are increasingly successful as halogen-free alternatives for various polymeric materials and applications. Phosphorus can act in the condensed phase by enhancing charring, yielding intumescence, or through inorganic glass formation; and in the gas phase through flame inhibition. Occurrence and efficiency depend, not only on the flame retardant itself, but also on its interaction with pyrolysing polymeric material and additives. Flame retardancy is sensitive to modification of the flame retardant, the use of synergists/adjuvants, and changes to the polymeric material. A detailed understanding facilitates the launch of tailored and targeted development. Full article

(This article belongs to the Special Issue Flame Retardants)

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197 KiB

Open AccessReview

Aryl Polyphosphonates: Useful Halogen-Free Flame Retardants for Polymers

by Li Chen and Yu-Zhong Wang

Materials 2010, 3(10), 4746-4760; https://doi.org/10.3390/ma3104746 - 11 Oct 2010

Cited by 78 | Viewed by 13226

Abstract

Aryl polyphosphonates (ArPPN) have been demonstrated to function in wide applications as flame retardants for different polymer materials, including thermosets, polycarbonate, polyesters and polyamides, particularly due to their satisfactory thermal stability compared to aliphatic flame retardants, and to their desirable flow behavior observed [...] Read more.

Aryl polyphosphonates (ArPPN) have been demonstrated to function in wide applications as flame retardants for different polymer materials, including thermosets, polycarbonate, polyesters and polyamides, particularly due to their satisfactory thermal stability compared to aliphatic flame retardants, and to their desirable flow behavior observed during the processing of polymeric materials. This paper provides a brief overview of the main developments in ArPPN and their derivatives for flame-retarding polymeric materials, primarily based on the authors’ research work and the literature published over the last two decades. The synthetic chemistry of these compounds is discussed along with their thermal stabilities and flame-retardant properties. The possible mechanisms of ArPPN and their derivatives containing hetero elements, which exhibit a synergistic effect with phosphorus, are also discussed. Full article

(This article belongs to the Special Issue Flame Retardants)

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299 KiB

Open AccessReview

Standard Dyes for Total Protein Staining in Gel-Based Proteomic Analysis

by François Chevalier

Materials 2010, 3(10), 4784-4792; https://doi.org/10.3390/ma3104784 - 20 Oct 2010

Cited by 27 | Viewed by 12135

Abstract

Staining of two-dimensional gels is a primary concern in proteomic studies using two-dimensional gel electrophoresis with respect to the number of proteins analyzed, the accuracy of spot quantification and reproducibility. In this review article, the efficiency of the most widely used dyes was [...] Read more.

Staining of two-dimensional gels is a primary concern in proteomic studies using two-dimensional gel electrophoresis with respect to the number of proteins analyzed, the accuracy of spot quantification and reproducibility. In this review article, the efficiency of the most widely used dyes was investigated. Visible dyes (Coomassie blue and silver nitrate), fluorescent dyes (Sypro Ruby, Deep Purple) and cyanine labeled methods were compared. Full article

(This article belongs to the Special Issue Advances in Dyes and Pigments)

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2055 KiB

Open AccessReview

Broadband Transformation Optics Devices

by Vera N. Smolyaninova, Igor I. Smolyaninov, Alexander V. Kildishev and Vladimir M. Shalaev

Materials 2010, 3(10), 4793-4810; https://doi.org/10.3390/ma3104793 - 21 Oct 2010

Cited by 7 | Viewed by 7966

Abstract

Recently we have suggested that two-dimensional broadband transformation optics devices based on metamaterial designs may be built using tapered waveguides. Here we review application of this principle to broadband electromagnetic cloaking, trapped rainbow, and novel microscopy devices. Full article

(This article belongs to the Special Issue Next Wave of Metamaterials)

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3104 KiB

Open AccessReview

Ion-Induced Nanoscale Ripple Patterns on Si Surfaces: Theory and Experiment

by Adrian Keller and Stefan Facsko

Materials 2010, 3(10), 4811-4841; https://doi.org/10.3390/ma3104811 - 22 Oct 2010

Cited by 98 | Viewed by 11202

Abstract

Nanopatterning of solid surfaces by low-energy ion bombardment has received considerable interest in recent years. This interest was partially motivated by promising applications of nanopatterned substrates in the production of functional surfaces. Especially nanoscale ripple patterns on Si surfaces have attracted attention both [...] Read more.

Nanopatterning of solid surfaces by low-energy ion bombardment has received considerable interest in recent years. This interest was partially motivated by promising applications of nanopatterned substrates in the production of functional surfaces. Especially nanoscale ripple patterns on Si surfaces have attracted attention both from a fundamental and an application related point of view. This paper summarizes the theoretical basics of ion-induced pattern formation and compares the predictions of various continuum models to experimental observations with special emphasis on the morphology development of Si surfaces during sub-keV ion sputtering. Full article

(This article belongs to the Special Issue Nanomaterials)

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572 KiB

Open AccessReview

Toxicity of Transition Metal Oxide Nanoparticles: Recent Insights from in vitro Studies

by Yue-Wern Huang, Chi-heng Wu and Robert S. Aronstam

Materials 2010, 3(10), 4842-4859; https://doi.org/10.3390/ma3104842 - 25 Oct 2010

Cited by 186 | Viewed by 16904

Abstract

Nanotechnology has evolved to play a prominent role in our economy. Increased use of nanomaterials poses potential human health risk. It is therefore critical to understand the nature and origin of the toxicity imposed by nanomaterials (nanotoxicity). In this article we review the [...] Read more.

Nanotechnology has evolved to play a prominent role in our economy. Increased use of nanomaterials poses potential human health risk. It is therefore critical to understand the nature and origin of the toxicity imposed by nanomaterials (nanotoxicity). In this article we review the toxicity of the transition metal oxides in the 4th period that are widely used in industry and biotechnology. Nanoparticle toxicity is compellingly related to oxidative stress and alteration of calcium homeostasis, gene expression, pro-inflammatory responses, and cellular signaling events. The precise physicochemical properties that dictate the toxicity of nanoparticles have yet to be defined, but may include element-specific surface catalytic activity (e.g., metallic, semiconducting properties), nanoparticle uptake, or nanoparticle dissolution. These in vitro studies substantially advance our understanding in mechanisms of toxicity, which may lead to safer design of nanomaterials. Full article

(This article belongs to the Special Issue Metal Nanoparticles)

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Materials, Volume 3, Issue 10 (October 2010) – 9 articles , Pages 4695-4859

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