Biology Chemistry III: Computers in Education High School
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Glass Ionomer Bone Cements Based on Magnesium-Containing Bioactive
Biomed. Glasses 2019; 5:1–12 Research Article Roland Wetzel, Leena Hupa, and Delia S. Brauer* Glass ionomer bone cements based on magnesium-containing bioactive glasses https://doi.org/10.1515/bglass-2019-0001 Received Sep 25, 2018; revised Dec 16, 2018; accepted Jan 14, 2019 1 Introduction Abstract: Glass ionomer cements (GIC) are used in restora- Cements for prosthetic stabilisation or spinal corrective tive dentistry and their properties (low heat during setting, surgeries (vertebroplasty, kyphoplasty) typically consist adhesion to mineralised tissue and surgical metals) make of polymethylmethacrylate [1, 2]. They exhibit a number them of great interest for bone applications. However, den- of drawbacks which include high curing temperatures tal GIC are based on aluminium-containing glasses, and or the presence of unreacted and toxic methacrylic acid the resulting release of aluminium ions from the cements monomers. They also do not bind to bone and are held in needs to be avoided for applications as bone cements. Re- place by mechanical interlocking only [2–6]. As a result, placing aluminium ions in glasses for use in glass ionomer there is a demand for alternative non-toxic cements with cements is challenging, as aluminium ions play a critical bone bonding capability. role in the required glass degradation by acid attack as Glass ionomer cements (GIC) have been used in well as in GIC mechanical stability. Magnesium ions have restorative dentistry as filler or luting materials for been used as an alternative for aluminium in the glass decades [7, 8]. They are formed by an acid-base reaction component, but so far no systematic study has looked into between a polymeric acid and an acid-degradable fluoro- the actual role of magnesium ions. -
Peroxide-Based Route for the Synthesis of Zinc Titanate Powder
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Arabian Journal of Chemistry (2016) xxx, xxx–xxx King Saud University Arabian Journal of Chemistry www.ksu.edu.sa www.sciencedirect.com ORIGINAL ARTICLE Peroxide-based route for the synthesis of zinc titanate powder N.V. Nikolenko a, A.N. Kalashnykova a, V.A. Solovov a, A.O. Kostyniuk b,*, H. Bayahia c, F. Goutenoire d a Department of Inorganic Substances Technology, Ukrainian State University of Chemical Technology, Dnipropetrovsk 49005, Ukraine b PetroSA Synthetic Fuels Innovation Centre, South African Institute for Advanced Materials Chemistry, University of the Western Cape, Cape Town, Private Bag X17, Bellville 7535, South Africa c Department of Chemistry, Albaha University, Albaha, P.O. Box 1988, 65431, Saudi Arabia d Laboratoire des Oxydes et Fluorures, UMR-CNRS 6010, Universite du Maine, 72085 Le Mans Cedex 9, France Received 12 April 2016; accepted 22 June 2016 KEYWORDS Abstract In this work the thermodynamical solubility diagrams of zinc and titanium hydroxides Zinc nitrate; were reviewed in order to determine the conditions for maximum degree of phase composition Titanium oxychloride; homogenization of precipitates. Experimental investigation of dependency of titanium peroxohy- Titanium peroxohydroxide; droxide solubility on solution acidity has been carried out and coprecipitation of zinc ions has been Zinc titanate; studied. It was concluded that precipitation by constant addition of mixed salts and base solutions Chemical precipitation into the mother liquor with constant acidity of pH 8.5 allows maximizing homogenization of precipitate composition. Thermal treatment process of mixed zinc and titanium hydroxides coprecipitated with hydrogen peroxide was studied using thermogravimetric analysis, differential thermal analysis and X-ray diffraction methods. -
Glass-Ionomer Cements in Restorative Dentistry: a Critical Appraisal Mohammed Almuhaiza
JCDP Glass-ionomer Cements in Restorative10.5005/jp-journals-10024-1850 Dentistry: A Critical Appraisal REVIEW ARTICLE Glass-ionomer Cements in Restorative Dentistry: A Critical Appraisal Mohammed Almuhaiza ABSTRACT make them useful as restorative and luting materials. Glass-ionomer cements (GICs) are mainstream restorative Glass-ionomer (GI) material was introduced by Wilson materials that are bioactive and have a wide range of uses, such and Kent in 1972 as a “new translucent dental filling as lining, bonding, sealing, luting or restoring a tooth. Although material” recommended for the restoration of cervical the major characteristics of GICs for the wider applications in lesions. It consists of a powdered fluoroaluminosilicate dentistry are adhesion to tooth structure, fluoride releasing capacity and tooth-colored restorations, the sensitivity to glass and a polyalkenoic acid. Polyacrylic acid is often moisture, inherent opacity, long-term wear and strength are incorporated into the powder in its dehydrated form, not as adequate as desired. They have undergone remarkable leaving the liquid to consist of water or an aqueous changes in their composition, such as the addition of metallic ions or resin components to their composition, which contributed solution of tartaric acid. The positive characteristics of the to improve their physical properties and diversified their use as GICs include chemical adhesion to enamel and dentin in a restorative material of great clinical applicability. The light- the presence of moisture, resistance -
JPRI Working Paper No. 3: October 1994 Strengths and Weaknesses of Education in Japan by Masao Kunihiro Academic Apartheid at Ja
JPRI Working Paper No. 3: October 1994 Strengths and Weaknesses of Education in Japan By Masao Kunihiro Academic Apartheid at Japan’s National Universities By Ivan P. Hall Strengths and Weaknesses of Education in Japan By Masao Kunihiro I am not, by any stretch of semantic generosity, an expert in either pedagogy or the sociology of knowledge. However, I have been associated with several universities as a teacher, and have published several books pertaining to education in the broad sense of the term, including translations into Japanese of David Riesman’s The Academic Revolution, Herbert Passin’s Society and Education in Japan, and Benjamin Duke’s The Japanese School. That is to say, I am interested in education as a human endeavor in general, and education in Japan in particular. I have also been associated with the educational end of NHK television and sat on the Education Committee in the Upper House of the Diet for a total of four years. Let me begin with some brief comments about the Sinitic Culture Area--of which Japan is a part--and the possible impact of Confucianism on education. According to Ronald Dore’s 1989 speech, “Confucianism, Economic Growth and Social Development,” there are four salient characteristics of Confucianism relevant to education. First: dutifulness to a larger collectivity, as opposed to individual rights to the pursuit of happiness. Second: the proclivity toward accepting a system of hierarchy. Third: special roles assigned to elites who are highly educated; those with knowledge are entitled to moral authority to rule. Fourth: rationality. Professor De Bary of Columbia University has maintained that, popular views of Confucianism as authoritarian to the contrary, a case can readily be made for both Liberalism and Democracy within the Confucian tradition. -
Effect of Polymerization and Type of Glass-Ionomer Cement on Thermal Behaviour
International Journal of Applied Science and Technology Vol. 2 No. 10; December 2012 Effect of Polymerization and Type of Glass-Ionomer Cement on Thermal Behaviour Kosmas TOLIDIS Department of Operative Dentistry School of Dentistry Aristotle University of Thessaloniki University Campus, 54124, Thessaloniki, Greece. Tiverios VAIMAKIS Section of Industrial and Food Chemistry Department of Chemistry School of Sciences University of Ioannina 45110, Ioannina, Greece. Christina BOUTSIOUKI Department of Operative Dentistry School of Dentistry Aristotle University of Thessaloniki University Campus, 54124, Thessaloniki, Greece. Paris GERASIMOU Department of Operative Dentistry School of Dentistry Aristotle University of Thessaloniki University Campus, 54124, Thessaloniki, Greece Abstract The purpose of this study was to evaluate the effect of type of glass-ionomer cement (GIC), extrinsic energy offer and light intensity of the curing device, on thermal behavior. Ketac Molar, 3M-ESPE, USA (KM), Diamond Rapid Set Capsules, Kemdent, Wiltshire, UK (D) and Ketac N100, 3M-ESPE, USA (KN), being all different types of GIC. o Measurements of coefficient of thermal expansion (CTE) were performed at 20-60 C and thermal behavior was evaluated in lower and higher temperatures. KM exhibits lower CTE values (p<0.001). D exhibits significant differences (p<0.001), showing greater CTE values. KN exhibits great differences (p<0.001) in higher temperatures. Qualitative differences were also noted in CTE diagrams, diversifying between expansion and contraction, as temperature raised. Type of GIC and light intensity of curing device affect thermal behavior. Extrinsic energy offer had no important effect on CTE values. Keywords: Coefficient of Thermal Expansion, Glass-Ionomer Cements, Dilatometer, Temperature, Polymerization 1. -
Compressive and Flexural Strengths of High-Strength Glass Ionomer Cements: a Systematic Review Ridyumna Garain1, Mikayeel Abidi2, Zain Mehkri3
REVIEW ARTICLE Compressive and Flexural Strengths of High-strength Glass Ionomer Cements: A Systematic Review Ridyumna Garain1, Mikayeel Abidi2, Zain Mehkri3 ABSTRACT Objective: To perform a systematic review of test methodologies of high-strength restorative glass ionomer cement (GIC) materials for compressive (CS) and flexural strengths (FS) to compare the results between different GICs. Materials and methods: Screening of titles and abstracts, data extraction, and quality assessment was conducted in search for in vitro studies, which reported on CS and/or FS properties of high-strength GIC. PubMed/Medline (US National Library of Medicine—National Institutes of Health), EBSCO, and ProQuest databases were searched for the relevant literature. Results: A total of 123 studies were found. These were then assessed based on preestablished inclusion and exclusion criteria. Of the selected studies, two studies of fair quality tested CS, while none tested FS. The CS of experimental groups in both studies was less than their respective control groups. Discussion: It was observed that many studies reported following the International Standards Organization (ISO) recommendations for testing but with modifications. Additionally, in absence of guidelines for testing other parameters that may be potentially advantageous, authors have used differing experimental techniques. These disparities make it difficult to draw comparisons between different studies. Conclusion: Only two studies of fair quality showed lower CS of experimental groups compared to their respective control groups. Lack of adherence to guidelines and lack of guidelines for potentially better test methodologies make it difficult to scrutinize and compare the validity of the research being conducted. Keywords: Compressive strength, Flexural strength, Glass ionomer cement, High strength GIC, Materials testing, Review, Standards. -
Glass Ionomer Cement
09-17-002 V1 GLASS IONOMER CEMENT INSTRUCTIONS FOR USE: RECOMMENDED INDICATIONS: IOS Glass Ionomer Cement represents an advanced, fluoride-releasing glass ionomer formulation designed for a broad scope of uses: 1. Cementation of metal or porcelain fused to metal crowns, bridges, inlays. 2. Cementation of stainless steel crowns or cementation of orthodontic bands. 3. Base or liner. CONTRAINDICATIONS: Pulp capping and sensitive teeth. COMPOSITION: Alumino silicate glass Polyacrylic acid PRODUCT PRESENTATION: Regular Kit (15gm Powder/15ml Liquid) # 17-211-102 Economy Kit (100gm Powder/60ml Liquid) # 17-211-103 INSTRUCTIONS FOR USE: 1. Prepare tooth cavity and base as required. 2. Clean and dry enamel and dentin thoroughly. 3. Shake powder bottle to uniformly blend the special powders. 4. Dispense 1 full scoop of powder to a mixing pad or glass slab. 5. Dispense 2 drops of liquid into the mixing pad or glass slab. When dispensing liquid, hold the dropper vertically. 6. Incorporate powder into liquid in small increments. Total mixing time should not exceed 30 seconds 7. Apply the material, without delay, in a uniform layer. 8. Placement of mixed cement should be done immediately while mix is still glossy; approximately 1& 1/2 to 2 minutes working time. If cement becomes dull, it should be discarded and a new mixture prepared. If a longer working time is needed, mix the cement on a cold, dry slab. 9. Keep restoration free from saliva or water for 5 minutes. Important Information: Excess cement should be removed with a cotton roll immediately, before it sets, and should be cleaned from all surrounding areas such as gingiva and adjacent teeth before final set. -
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SPACE STATION THERMAL CONTROL SURFACES C. R. Maag M. T. Grenier VOLUME It - LITERATURE SEARCH PREPARED FOR NATIONAL AERONAUTICS AND SPACE ADMINISTRATION MARSHALL SPACE FLIGHT CENTER, ALABAMA 35812 CONTRACT NAS 8-32637 Report 5666 March 1978 Volume I[ A4E,,MOCT ELEL-TL7S4'STE1S AZUSA. CALIFORNIA S(NASA-CE-150668) SPACE STA TION THERMA1. N78-22137 CONTPBOL SURFACES. VOLUME 2: LITERATURE SEARCH Interim Report, 4 Aug. 1977 - 4 Feb. 1978 (Aerojet Electrosystems Co-) 410 p Unclas BC A18/MF A01 CSCI 05A GI3/15 645 Report 5666 FOREWORD This interim report describes results of the first six months of a study on Contract NAS 8-32637, "Space Station Thermal Control Surfaces." The contract was initiated on 4 August 1977 as a-6-month study to assess the deficiencies between the state of the art in thermal--control surface technology and that which would be required for both a 25-kW power module and a 25-year mission space station. The Scope of Work of the contract has been modified to include ad ditional emphasis on Task I, "Requirements Analysis," and the period of per formance will be extended for an additional eight months of effort. The final report is being deferred until the end of the extended period of performance. This report covers the period of 4 August 1977 to 4 February 1978,) and is submitted in two volumes. The literature search and survey portion of this study are contained in Volume II. This study was performed by personnel of Aerojet ElectroSystems Company, for the Space Sciences Laboratory of NASA-Marshall Flight Center. -
Annual Report
ANNUAL REPORT 2004 Northeastern Section American Chemical Society Local Section Name: Northeastern Section URL for Total Report: http://www.nesacs.org Prof. Jean A. Fuller-Stanley Chair 2004 Northeastern Section, ACS 2 TABLE OF CONTENTS (Pages numbered separately by section) Pages PART I - QUESTIONNAIRE Annual Report Questionnaire ....................................................................................................................................7 PART II: ANNUAL NARRATIVE REPORT Activities: National Chemistry Week ...................................................................................................................17 Phyllis A. Brauner Memorial Lecture................................................................................................17 Northeast Student Chemistry Research Conference (NSCRC) .......................................................18 Northeast Regional Undergraduate Day............................................................................................18 Undergraduate Environmental Research Symposium .....................................................................18 Connections to Chemistry ...................................................................................................................19 NESACS Vendor Fair and Medicinal Chemistry Symposium.........................................................19 NESACS Fundraising Booklet19........................................................................................................19 ACS Scholars Program........................................................................................................................20 -
The Behavior of Several White Pigments As Determined by in Situ Reflectance Measurements of Irradiated Specimens*
THE BEHAVIOR OF SEVERAL WHITE PIGMENTS AS DETERMINED BY IN SITU REFLECTANCE MEASUREMENTS OF IRRADIATED SPECIMENS* G. A. Zerlaut and F. 0. Rogers IIT Research Institute Technology Center Chicago, Illinois 60616 ABSTRACT This paper is a review of materials research relating pri- marily to two white pigment materials -- zinc oxide and zinc orthotitanate, The zinc oxide studies inciude 1) investigation of the photodesorption problem associated with the irradiation of zinc oxide in vacuum, 2) elucidation of the resultant and concornmittant generation of an infrared-centered abspption band, and 3) prevention of the development of photodesorption- related infrared absorption by treating the zinc oxide surface with alkali silicates. The zinc orthotitanate studies relate to 1) the synthesis of zinc titanates having various controlled *The work reported was supported in part by NASA - Marshall Space Flight Center Contracts NAS8-5379 and NAS8-21074 and Jet Propulsion Laboratory Contract 951737 (subcontract under NwS~--~OO), The authors gratefully acknowledge the suggestions and criticisms sf Messers, D,W, Gates, W, F, Carroll and E,R, Miller, he preparation of the qraphs by H, BeYoung is also gratefully acknowledged, stoichimetry and optical properties, 3) the relation between heat-treatment and stability to ultraviolet irradiation in vacuum, and 4) the photodesorption phenomena associated with zinc titanates. INTRODUCTION Until 1965, zinc oxide was thought to be the most stable white pigment available in terms of stability of its hemispheri- 1-3 cal spectral reflectance to ultraviolet irradiation in vacuum. However, serious discrepancies in zinc oxide's behavior were re- ported between laboratory-simulation data and flight-experiment data obtained from OSO-11~and the pegasus5 materialstexperiments. -
Syntheses, Crystal Structures and Magnetic Properties of Two Cyano-Bridged Two-Dimensional Assemblies [Fe(Salpn)]2 [Fe(CN)5NO] and [Fe(Salpn)]2[Ni(CN)4]
Transition Metal Chemistry 29: 100–106, 2004. 100 Ó 2004 Kluwer Academic Publishers. Printed in the Netherlands. Syntheses, crystal structures and magnetic properties of two cyano-bridged two-dimensional assemblies [Fe(salpn)]2 [Fe(CN)5NO] and [Fe(salpn)]2[Ni(CN)4] Xiao-Ping Shen and Zheng Xu* Coordination Chemistry Institute, State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, PR China Ai-Hua Yuan Department of Material and Environmental Engineering, East China Shipbuilding Institute, Zhenjiang 212003, PR China Zi-Xiang Huang State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, PR China Received 13 May 2003; accepted 07 July 2003 Abstract III II III II Two cyano-bridged assemblies, [Fe (salpn)]2[Fe (CN)5NO] (1) and [Fe (salpn)]2[Ni (CN)4] (2) [salpn ¼ N, N¢- 1,2-propylenebis(salicylideneiminato)dianion], have been prepared and structurally and magnetically characterized. 2) 2) + In each complex, [Fe(CN)5NO] or [Ni(CN)4] coordinates with four [Fe(salpn)] cations using four co-planar ) + 2) 2) CN ligands, whereas each [Fe(salpn)] links two [Fe(CN)5NO] or [Ni(CN)4] ions in the trans form, which II III results in a two-dimensional (2D) network consisting of pillow-like octanuclear [AM ACNAFe ANCA]4 units 2) (M ¼ Fe or Ni). In complex (1), the NO group of [Fe(CN)5NO] remains monodentate and the bond angle of FeIIANAO is 180.0°. The variable temperature magnetic susceptibilities, measured in the 5–300 K range, show weak intralayer antiferromagnetic interactions in both complexes with the intramolecular iron(III)ÁÁÁiron(III) exchange integrals of )0.017 cm)1 for (1) and –0.020 cm-1 for (2), respectively. -
Assembly of Multifunctional Materials Using Molecular Cluster Building Blocks
Assembly of Multifunctional Materials Using Molecular Cluster Building Blocks Bonnie Choi Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Graduate School of Arts and Sciences Columbia University 2018 © 2018 Bonnie Choi All rights reserved Abstract Assembly of Multifunctional Materials Using Molecular Cluster Building Blocks Bonnie Choi This thesis explores the synthesis, properties, and potential applications of molecular clusters and the hierarchical solids that form when complementary clusters are combined. Chapter 1 introduces the diverse set of molecular clusters that I employ as nanoscale building blocks in the assembly of multifunctional materials. The core structure of the molecular clusters is closely related to the superconducting Chevrel phases. In discrete clusters, however, the core is passivated by organic ligands, which add stability and important functionalities. The molecular clusters have rich physical and chemical properties of their own, and I present some of the techniques used to investigate their intrinsic electronic properties. Finally, I review some of the modes by which the molecular clusters interact with another to assemble into hierarchical solids. The structural tunability and complexity embedded in the molecular clusters will enable the design of modular, well-defined, multifunctional materials with desirable electronic and magnetic properties. Chapter 2 details the synthesis and characterization of a family of manganese telluride molecular clusters. By varying the ligands that decorate the surface of the inorganic core, I show that the core structures can be tuned. The study of molecular clusters provides insight into how extended solids form. As such, I make structural comparisons of the clusters to known solid-state compounds.