Surface Dissolution and Nucleation Processes Alexander Stuart Parker

Total Page:16

File Type:pdf, Size:1020Kb

Surface Dissolution and Nucleation Processes Alexander Stuart Parker A Thesis Submitted for the Degree of PhD at the University of Warwick Permanent WRAP URL: http://wrap.warwick.ac.uk/88282 Copyright and reuse: This thesis is made available online and is protected by original copyright. Please scroll down to view the document itself. Please refer to the repository record for this item for information to help you to cite it. Our policy information is available from the repository home page. For more information, please contact the WRAP Team at: [email protected] warwick.ac.uk/lib-publications Quantitative Crystal Investigations: Surface Dissolution and Nucleation Processes Alexander Stuart Parker Thesis submitted for the degree of Doctor of Philosophy Electrochemistry and Interfaces Group, Department of Chemistry, University of Warwick. June 2016 For my loving family i Quantitative Crystal Investigations: Surface Dissolution and Nucleation Processes Alexander Stuart Parker I. Table of Contents I. TABLE OF CONTENTS ____________________________________________ II II. LIST OF FIGURES ____________________________________________ VII III. LIST OF TABLES _____________________________________________ XIII IV. DECLARATION AND INCLUSION OF PUBLISHED WORK _____________XIV V. ACKNOWLEDGEMENTS _______________________________________XVI VI. DEFINITION OF ACRONYMS __________________________________ XVII VII. GLOSSARY OF SYMBOLS ______________________________________ XIX VIII. ABSTRACT _________________________________________________ XX 1 INTRODUCTION ________________________________________________ 2 1.1 SURFACE SCIENCE_____________________________________________ 3 1.2 ENAMEL ___________________________________________________ 4 1.2.1 Structure of the Tooth ____________________________________ 4 1.2.2 Prevalence of acid dissolution in the oral cavity ________________ 8 1.2.3 Introduction to Acid Erosion and Remineralisation _____________ 9 1.2.4 Enamel Dissolution ______________________________________ 12 1.2.5 Enamel Dissolution Inhibitors _____________________________ 16 1.2.6 Enamel summary _______________________________________ 17 1.3 CALCIUM CARBONATE CRYSTALS __________________________________ 18 ii 1.3.1 Applications of Crystal Nucleation, Growth and Dissolution _____ 22 1.3.2 Crystal Nucleation Theory ________________________________ 24 1.3.3 Polymorphism __________________________________________ 27 1.3.4 Applications to CaCO3 ___________________________________ 30 1.3.5 Confinement of crystal growth ____________________________ 32 1.3.6 Calcium Carbonate growth inhibition _______________________ 33 1.4 MASS TRANSPORT AND SURFACE REACTION KINETICS ___________________ 36 1.5 TECHNIQUES FOR SURFACE ANALYSIS _______________________________ 37 1.5.1 Optical Microscopy ______________________________________ 37 1.5.2 SPM Methods __________________________________________ 38 1.5.3 Field Emission Scanning Electron Microscopy (FE-SEM) _________ 54 1.5.4 Micro-Raman Microscopy ________________________________ 55 1.6 FINITE ELEMENT METHOD (FEM) MODELLING _________________________ 57 1.7 CHEMICALS, INSTRUMENTATION AND METHODS _______________________ 59 1.8 THESIS AIMS _______________________________________________ 60 2 COMBINATORIAL LOCALIZED DISSOLUTION ANALYSIS: APPLICATION TO ACID-INDUCED DISSOLUTION OF DENTAL ENAMEL AND THE EFFECT OF SURFACE TREATMENTS ____________________________________________________________ 64 2.1 ABSTRACT _________________________________________________ 64 2.2 INTRODUCTION _____________________________________________ 65 2.3 EXPERIMENTAL DETAILS ________________________________________ 69 2.3.1 Solutions ______________________________________________ 69 2.3.2 Enamel Sample Preparation ______________________________ 70 2.3.3 SECCM method _________________________________________ 72 2.3.4 Atomic Force Microscopy _________________________________ 76 2.4 THEORY AND SIMULATIONS _____________________________________ 76 iii 2.5 RESULTS AND DISCUSSION ______________________________________ 81 2.5.1 Etch Pit analysis ________________________________________ 81 2.5.2 Simulations ____________________________________________ 86 2.5.3 Determination of dissolution kinetics _______________________ 87 2.6 CONCLUSIONS ______________________________________________ 89 3 MEASUREMENT OF THE EFFICACY OF CALCIUM SILICATE FOR THE PROTECTION AND REPAIR OF DENTAL ENAMEL ________________________________ 92 3.1 ABSTRACT _________________________________________________ 92 3.1.1 Objectives: ____________________________________________ 92 3.1.2 Methods: _____________________________________________ 92 3.1.3 Results: _______________________________________________ 93 3.1.4 Conclusions: ___________________________________________ 93 3.1.5 Clinical Significance _____________________________________ 93 3.2 INTRODUCTION. _____________________________________________ 94 3.3 MATERIALS AND METHODS _____________________________________ 98 3.3.1 Calcium release from calcium silicate _______________________ 98 3.3.2 HAP formation from calcium silicate ________________________ 98 3.3.3 Scanning electrochemical cell microscopy (SECCM) ____________ 99 3.3.4 Deposition of calcium silicate onto sound and eroded enamel surfaces _________________________________________________ 102 3.3.5 Deposition of calcium silicate to eroded enamel pits __________ 103 3.3.6 Protection of enamel by calcium silicate and fluoride _________ 104 3.4 RESULTS _________________________________________________ 106 3.4.1 Calcium release from calcium silicate ______________________ 106 3.4.2 HAP formation from calcium silicate _______________________ 108 iv 3.4.3 Deposition of calcium silicate onto sound and eroded enamel surfaces _________________________________________________ 111 3.4.4 Deposition of calcium silicate to eroded enamel pits __________ 111 3.4.5 Protection of enamel by calcium silicate and fluoride _________ 114 3.5 DISCUSSION ______________________________________________ 117 3.6 CONCLUSIONS _____________________________________________ 120 4 CONTROLLED CRYSTALLIZATION IN A NANOPIPETTE ________________ 122 4.1 ABSTRACT ________________________________________________ 122 4.2 INTRODUCTION ____________________________________________ 123 4.3 MATERIALS AND METHODS ________________________________ 128 4.3.1 Solutions. ____________________________________________ 128 4.3.2 Nanopipettes. _________________________________________ 128 4.3.3 Pipette Characterization ________________________________ 129 4.3.4 Instrumentation. ______________________________________ 129 4.3.5 Bias Driven Crystallization Experiments. ____________________ 130 2+ 4.3.6 Variation of Ca concentration in the bath solution __________ 132 2- 4.3.7 Effect of inverting the tip and bath species whilst varying of CO3 concentration in the bath solution ____________________________ 133 4.3.8 FEM Simulations. ______________________________________ 134 4.3.9 Raman Spectroscopy. ___________________________________ 136 4.4 RESULTS AND DISCUSSION _________________________________ 137 4.4.1 Initial Experiments _____________________________________ 137 4.4.2 Growth of Calcium Carbonate in a Nanopipette ______________ 138 4.4.3 Mixing of CaCO3 in a Nanopipette _________________________ 141 4.4.4 Quantifying Growth Rates in a Nanopipette _________________ 145 4.4.5 The Effect of Applied Bias on Blocking Rates ________________ 149 v 4.4.6 Inhibitor Studies Using a Nanopipette ______________________ 151 4.5 CONCLUSIONS ___________________________________________ 154 5 CONCLUSIONS _______________________________________________ 158 6 BIBLIOGRAPHY _______________________________________________ 162 vi II. List of figures FIGURE 1 SHOWING MODEL STRUCTURE OF TOOTH AND ROD STRUCTURE. WHITE SHOWS ENAMEL, YELLOW SHOWS DENTINE AND RED SHOWS PULP AND NERVE TISSUE ......................................................... 5 FIGURE 2 SHOWING AFM IMAGE OF A. ACID ERODED AND B. HIGHLY POLISHED ENAMEL SURFACE WHICH REVEALS THE INTERLOCKING ROD STRUCTURE. DATA COLLECTED BY THE AUTHOR ............................. 7 FIGURE 3 SHOWING EFFECT OF ACID ON POLISHED ENAMEL USING INTERFEROMETRY TO SHOW THE BOUNDARY BETWEEN ACID ETCHED PART OF AN ENAMEL SAMPLE AND UNTREATED ENAMEL. CLOSE UP IMAGED PRODUCED FROM AFM ............................................................................................ 9 FIGURE 4 SHOWING THE VARIOUS STAGES OF DISSOLUTION AND THE AREAS OF KINETIC AND MASS TRANSPORT LIMITS ............................................................................................................................ 14 FIGURE 5 FREE ENERGY DIAGRAM FOR NUCLEATION ......................................................................... 25 FIGURE 6 SHOWING ENERGY CHANGE DIAGRAM OF METASTABLE AND THERMODYNAMIC CRYSTALS ........... 29 FIGURE 7 AFM EXPERIMENT SET UP ............................................................................................. 40 FIGURE 8 SHOWING A TYPICAL FORCE CURVE MEASURED USING AFM .................................................. 42 FIGURE 9 OPERATION OF TAPPING MODE AFM ............................................................................... 43 FIGURE 10 SHOWING AN AFM TIP INTERATING WITH A SHARP FEATURE WHICH WOULD CREATE A FALSE IMMAGE ......................................................................................................................... 44 FIGURE 11 SHOWING SERIES OF AFM LINE PROFILES AT VARIOUS TIMES OF AN ARRAY OF ACID ETCHED PITS ON A) POLISHED ENAMEL B) FLUORIDE TREATED POLISHED ENAMEL ...........................................
Recommended publications
  • Paleoceanographical Proxies Based on Deep-Sea Benthic Foraminiferal Assemblage Characteristics
    CHAPTER SEVEN Paleoceanographical Proxies Based on Deep-Sea Benthic Foraminiferal Assemblage Characteristics Frans J. JorissenÃ, Christophe Fontanier and Ellen Thomas Contents 1. Introduction 263 1.1. General introduction 263 1.2. Historical overview of the use of benthic foraminiferal assemblages 266 1.3. Recent advances in benthic foraminiferal ecology 267 2. Benthic Foraminiferal Proxies: A State of the Art 271 2.1. Overview of proxy methods based on benthic foraminiferal assemblage data 271 2.2. Proxies of bottom water oxygenation 273 2.3. Paleoproductivity proxies 285 2.4. The water mass concept 301 2.5. Benthic foraminiferal faunas as indicators of current velocity 304 3. Conclusions 306 Acknowledgements 308 4. Appendix 1 308 References 313 1. Introduction 1.1. General Introduction The most popular proxies based on microfossil assemblage data produce a quanti- tative estimate of a physico-chemical target parameter, usually by applying a transfer function, calibrated on the basis of a large dataset of recent or core-top samples. Examples are planktonic foraminiferal estimates of sea surface temperature (Imbrie & Kipp, 1971) and reconstructions of sea ice coverage based on radiolarian (Lozano & Hays, 1976) or diatom assemblages (Crosta, Pichon, & Burckle, 1998). These à Corresponding author. Developments in Marine Geology, Volume 1 r 2007 Elsevier B.V. ISSN 1572-5480, DOI 10.1016/S1572-5480(07)01012-3 All rights reserved. 263 264 Frans J. Jorissen et al. methods are easy to use, apply empirical relationships that do not require a precise knowledge of the ecology of the organisms, and produce quantitative estimates that can be directly applied to reconstruct paleo-environments, and to test and tune global climate models.
    [Show full text]
  • Soares, R. Et Al
    Original Article DOI: 10.7860/JCDR/2017/23594.9758 Assessment of Enamel Remineralisation After Treatment with Four Different Dentistry Section Remineralising Agents: A Scanning Electron Microscopy (SEM) Study RENITA SOARES1, IDA DE NORONHA DE ATAIDE2, MARINA FERNANDES3, RAJAN LAMBOR4 ABSTRACT these groups were remineralised using the four remineralising Introduction: Decades of research has helped to increase our agents. The treated groups were subjected to pH cycling over a knowledge of dental caries and reduce its prevalence. However, period of 30 days. This was followed by assessment of surface according to World Oral Health report, dental caries still remains microhardness and SEM for qualitative evaluation of surface a major dental disease. Fluoride therapy has been utilised in changes. The results were analysed by One-Way Analysis Of a big way to halt caries progression, but has been met with Variance (ANOVA). Multiple comparisons between groups were limitations. This has paved the way for the development of performed by paired t-test and post-hoc Tukey test. newer preventive agents that can function as an adjunct to Results: The results of the study revealed that remineralisation of fluoride or independent of it. enamel was the highest in samples of Group E (Self assembling Aim: The purpose of the present study was to evaluate the ability peptide P11-4) followed by Group B (CPP-ACPF), Group C (BAG) of Casein Phosphopeptide-Amorphous Calcium Phosphate and Group D (fluoride enhanced HA gel). There was a significant Fluoride (CPP ACPF), Bioactive Glass (BAG), fluoride enhanced difference (p<0.05) in the remineralising ability between the self assembling peptide P -4 group and BAG and fluoride Hydroxyapatite (HA) gel and self-assembling peptide P11-4 to 11 remineralise artificial carious lesions in enamel in vitro using enhanced HA gel group.
    [Show full text]
  • An Updated Synthesis of the Impacts of Ocean Acidification on Marine Biodiversity 2 3 ACKNOWLEDGEMENTS
    P a g e | 1 DRAFT FOR CBD PEER-REVIEW ONLY; NOT TO QUOTE; NOT TO CIRCULATE 1 An updated synthesis of the impacts of ocean acidification on marine biodiversity 2 3 ACKNOWLEDGEMENTS ....................................................................................................... 3 4 5 EXECUTIVE SUMMARY ....................................................................................................... 4 6 7 1. Background and introduction ............................................................................................... 8 8 1.1. Mandate of this review .......................................................................................................... 8 9 1.2. What is ocean acidification? ........................................................................................ 9 10 1.3. Re-visiting key knowledge gaps identified in the previous CBD review ................... 14 11 12 2. Scientific and policy framework ........................................................................................ 17 13 2.1. Steps towards global recognition and international science collaboration ................. 17 14 2.2. Intergovernmental interest in ocean acidification and actions to date ........................ 19 15 16 3. Global status and future trends of ocean acidification ....................................................... 23 17 3.1. Variability .................................................................................................................. 23 18 3.2. Modelled simulations of future ocean
    [Show full text]
  • Biotribology Recent Progresses and Future Perspectives
    HOSTED BY Available online at www.sciencedirect.com Biosurface and Biotribology ] (]]]]) ]]]–]]] www.elsevier.com/locate/bsbt Biotribology: Recent progresses and future perspectives Z.R. Zhoua,n, Z.M. Jinb,c aSchool of Mechanical Engineering, Southwest Jiaotong University, Chengdu, China bSchool of Mechanical Engineering, Xian Jiaotong University, Xi'an, China cSchool of Mechanical Engineering, University of Leeds, Leeds, UK Received 6 January 2015; received in revised form 3 March 2015; accepted 3 March 2015 Abstract Biotribology deals with all aspects of tribology concerned with biological systems. It is one of the most exciting and rapidly growing areas of tribology. It is recognised as one of the most important considerations in many biological systems as to the understanding of how our natural systems work as well as how diseases are developed and how medical interventions should be applied. Tribological studies associated with biological systems are reviewed in this paper. A brief history, classification as well as current focuses on biotribology research are analysed according to typical papers from selected journals and presentations from a number of important conferences in this area. Progress in joint tribology, skin tribology and oral tribology as well as other representative biological systems is presented. Some remarks are drawn and prospects are discussed. & 2015 Southwest Jiaotong University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Keywords: Biotribology; Biosurface; Joint; Skin; Dental Contents 1. Introduction ...................................................................................2 2. Classifications and focuses of current research. ..........................................................3 3. Joint tribology .................................................................................4 3.1.
    [Show full text]
  • Climate Change and Ocean Acidification Impacts on Lower
    EGU Journal Logos (RGB) Open Access Open Access Open Access Advances in Annales Nonlinear Processes Geosciences Geophysicae in Geophysics Open Access Open Access Natural Hazards Natural Hazards and Earth System and Earth System Sciences Sciences Discussions Open Access Open Access Atmospheric Atmospheric Chemistry Chemistry and Physics and Physics Discussions Open Access Open Access Atmospheric Atmospheric Measurement Measurement Techniques Techniques Discussions Open Access Biogeosciences, 10, 5831–5854, 2013 Open Access www.biogeosciences.net/10/5831/2013/ Biogeosciences doi:10.5194/bg-10-5831-2013 Biogeosciences Discussions © Author(s) 2013. CC Attribution 3.0 License. Open Access Open Access Climate Climate of the Past of the Past Discussions Climate change and ocean acidification impacts on lower trophic Open Access Open Access levels and the export of organic carbon to the deepEarth ocean System Earth System Dynamics 1 1 1 2 1 Dynamics A. Yool , E. E. Popova , A. C. Coward , D. Bernie , and T. R. Anderson Discussions 1National Oceanography Centre, University of Southampton Waterfront Campus, European Way, Southampton SO14 3ZH, UK Open Access Open Access 2Met Office Hadley Centre, FitzRoy Road, Exeter EX1 3PB, UK Geoscientific Geoscientific Instrumentation Instrumentation Correspondence to: A. Yool ([email protected]) Methods and Methods and Received: 29 January 2013 – Published in Biogeosciences Discuss.: 25 February 2013 Data Systems Data Systems Revised: 18 July 2013 – Accepted: 19 July 2013 – Published: 5 September 2013 Discussions
    [Show full text]
  • Understanding the Ocean's Biological Carbon Pump in the Past: Do We Have the Right Tools?
    Manuscript prepared for Earth-Science Reviews Date: 3 March 2017 Understanding the ocean’s biological carbon pump in the past: Do we have the right tools? Dominik Hülse1, Sandra Arndt1, Jamie D. Wilson1, Guy Munhoven2, and Andy Ridgwell1, 3 1School of Geographical Sciences, University of Bristol, Clifton, Bristol BS8 1SS, UK 2Institute of Astrophysics and Geophysics, University of Liège, B-4000 Liège, Belgium 3Department of Earth Sciences, University of California, Riverside, CA 92521, USA Correspondence to: D. Hülse ([email protected]) Keywords: Biological carbon pump; Earth system models; Ocean biogeochemistry; Marine sedi- ments; Paleoceanography Abstract. The ocean is the biggest carbon reservoir in the surficial carbon cycle and, thus, plays a crucial role in regulating atmospheric CO2 concentrations. Arguably, the most important single com- 5 ponent of the oceanic carbon cycle is the biologically driven sequestration of carbon in both organic and inorganic form- the so-called biological carbon pump. Over the geological past, the intensity of the biological carbon pump has experienced important variability linked to extreme climate events and perturbations of the global carbon cycle. Over the past decades, significant progress has been made in understanding the complex process interplay that controls the intensity of the biological 10 carbon pump. In addition, a number of different paleoclimate modelling tools have been developed and applied to quantitatively explore the biological carbon pump during past climate perturbations and its possible feedbacks on the evolution of the global climate over geological timescales. Here we provide the first, comprehensive overview of the description of the biological carbon pumpin these paleoclimate models with the aim of critically evaluating their ability to represent past marine 15 carbon cycle dynamics.
    [Show full text]
  • Author's Tracked Changes
    Toward a global calibration for quantifying past oxygenation in oxygen minimum zones using benthic Foraminifera Martin Tetard1, Laetitia Licari1, Ekaterina Ovsepyan2, Kazuyo Tachikawa1, and Luc Beaufort1 1Aix Marseille Univ, CNRS, IRD, Coll France, INRAE, CEREGE, Aix-en-Provence, France. 2Shirshov Institute of Oceanology, Russian Academy of Sciences, Moscow, Russia. Correspondence: M. Tetard ([email protected]) Abstract. Oxygen Minimum Zones (OMZs) are oceanic areas largely depleted in dissolved oxygen, nowadays considered in expansion in the face of global warming. To investigate the relationship between OMZ expansion and global climate changes during the late Quaternary, quantitative oxygen reconstructions are needed, but are still in their early development. 5 Here, past bottom water oxygenation (BWO) was quantitatively assessed through a new, fast, semi-automated, and taxon-free :::::::::::::::taxon-independent morphometric analysis of benthic foraminiferal tests, developed and calibrated using Eastern North Pacific(ENP ::::WNP::::::::(Western::::::North:::::::Pacific, ::::::::including:::its ::::::::marginal :::::seas), ::::ENP::::::::(Eastern :::::North:::::::Pacific) and the ESP:::::(Eastern South Pa- cific(ESP) OMZs samples. This new approach is based on an average size and circularity index for each sample. This method, as well as two already published micropalaeontological approaches techniques:::::::::based on benthic foraminiferal assemblages 10 variability and porosity investigation of a single species, were here calibrated based on availability of new data from 23 45:: -1 core tops recovered along an oxygen gradient (from 0.03 to 1.79 2.88::::mL.L ) from the ENP, ESP, :::::WNP, ::::ENP,::::EEP::::::::(Eastern ::::::::Equatorial::::::::Pacific), ::::ESP,::::::::SWACM::::::(South:::::West :::::::African ::::::::::Continental :::::::Margin),:AS (Arabian Sea) and WNP (Western North Pacific, including its marginal seas) OMZs.
    [Show full text]
  • Synthese Nutriscope: Arbeiten Von Agroscope Auf Dem Gebiet Der Ernährung 2008 Bis 2010
    Synthese NutriScope: Arbeiten von Agroscope auf dem Gebiet der Ernährung 2008 bis 2010 Pascale Mühlemann Mühlemann Nutrition GmbH März 2011 Synthese Ernährung Impressum Autorin Mühlemann Nutrition GmbH Pascale Mühlemann www.muehlemann-nutrition.ch Auftraggeberin Forschungsanstalt Agroscope Liebefeld-Posieux ALP www.agroscope.admin.ch Bemerkungen Die vorliegende Synthese basiert ausschliesslich auf Arbeiten von Agroscope auf dem Ge- biet der Ernährung, die in irgendeiner Art und Weise öffentlich gemacht wurden. Die beige- zogenen Arbeiten wurden in den Jahren 2008 bis 2010 durchgeführt, wobei auch relevante Arbeiten aus den Vorjahren und einige aktuelle Publikationen aus dem Jahr 2011 einge- schlossen wurden. Das Literaturverzeichnis umfasst insofern ausschliesslich an Agroscope durchgeführte Arbeiten; die darin aufgeführten Originalarbeiten sind im Literaturverzeichnis nicht genannt. Da Agroscope-eigene Arbeiten gegenüber reinen Literaturarbeiten im Vordergrund stehen, sind Erstere in der vorliegenden Synthese in einen Rahmen gesetzt. 9. März 2011 - 2 - Synthese Ernährung Inhaltsverzeichnis Impressum .............................................................................................................................. 2 Abkürzungsverzeichnis ......................................................................................................... 5 Zusammenfassung ................................................................................................................. 6 1. Milch und Milchprodukte .............................................................................................
    [Show full text]
  • Resolving Ecological Feedbacks on the Ocean Carbon Sink in Earth System Models” by Armstrong Mckay Et Al
    Review of “Resolving ecological feedbacks on the ocean carbon sink in Earth system models” by Armstrong McKay et al. Armstrong McKay et al., have put a lot of of effort into revising the manuscript and responding to the reviewer comments, especially given the varied pressures of working during a pandemic. Overall, I think the manuscript is improved with the addition of adequate details about the experimental set up, new analysis of results and improved general presentation. The overall concept and findings are interesting to the Earth system community and are currently very relevant to a wider discussion of resolving plankton ecosystems in Earth system models. Unfortunately I think there are still some outstanding issues with the experimental set-up and analysis that need to be resolved before I can recommend the manuscript for publication. Overall, I think the problems described in the comment by Kvale et al., combined with my own comments highlight a broader issue: can a common baseline be defined for different models and does this limit the level of quantitative analysis? This seems like a tricky issue to resolve but I have tried to outline two ways in which I think it could be achieved below as I think this is worth pursuing. I have also included a more detailed criticism of the recalibration process now that the process has been fully described, but this forms a part of the broader issue. Experimental Set-up Based on the previous reviewer comments and the clarifications in the revised manuscript, I think there is a fundamental issue in trying to define a common baseline for all the experiments.
    [Show full text]
  • In Vitro Enamel Remineralization Efficacy of Calcium Silicate-Sodium Phosphate-Fluoride Salts Versus Novamin Bioactive Glass, Following Tooth Whitening
    Published online: 2021-02-23 THIEME Original Article 515 In Vitro Enamel Remineralization Efficacy of Calcium Silicate-Sodium Phosphate-Fluoride Salts versus NovaMin Bioactive Glass, Following Tooth Whitening 1 2,3 4 5 Hatem M. El-Damanhoury Nesrine A. Elsahn Soumya Sheela Talal Bastaty 1 Department of Preventive and Restorative Dentistry, Address for correspondence Hatem El-Damanhoury, BDS, MS, College of Dental Medicine, University of Sharjah, Sharjah, PhD, Room M28-129 , College of Dental Medicine , University United Arab Emirates of Sharjah, P.O. Box: 27272, Sharjah , United Arab Emirates 2 Department of Clinical Sciences, College of Dentistry, Ajman (e-mail: [email protected] ) . University, Ajman, United Arab Emirates 3 Department of Operative Dentistry, Faculty of Dentistry, Cairo University, Cairo, Egypt 4 Dental Biomaterials Research Group, Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates 5 College of Dental Medicine, University of Sharjah, Sharjah, United Arab Emirates Eur J Dent:2021;15:515–522 Abstract Objectives This study aimed to evaluate the effect of in-office bleaching on the enamel surface and the efficacy of calcium silicate-sodium phosphate-fluoride salt (CS) and NovaMin bioactive glass (NM) dentifrice in remineralizing bleached enamel. Materials and Methods Forty extracted premolars were sectioned mesio-distally, and the facial and lingual enamel were flattened and polished. The samples were equally divided into nonbleached and bleached with 38% hydrogen peroxide (HP). Each group was further divided according to the remineralization protocol ( n = 10); no remineralization treatment (nontreated), CS, or NM, applied for 3 minutes two times/ day for 7 days, or CS combined with NR-5 boosting serum (CS+NR-5) applied for 3 minutes once/day for 3 days.
    [Show full text]
  • Resolving Ecological Feedbacks on the Ocean Carbon Sink in Earth System Models David I
    Resolving ecological feedbacks on the ocean carbon sink in Earth system models David I. Armstrong McKay*1,2, Sarah E. Cornell1,2, Katherine Richardson3, Johan Rockström1,4 1Stockholm Resilience Centre, Stockholm University, Stockholm, 106 91, Sweden 5 2Bolin Centre for Climate Research, Stockholm University, Stockholm, 106 91, Sweden 3Globe Institute, Center for Macroecology, Evolution and Climate, University of Copenhagen, Copenhagen, 2100, Denmark 4Potsdam Institute for Climate Impact Research, Potsdam, 14473, Germany Correspondence to: David I. Armstrong McKay ([email protected]) Abstract. The Earth’s oceans are one of the largest sinks in the Earth system for anthropogenic CO2 emissions, acting as a 10 negative feedback on climate change. Earth system models predict, though, that climate change will lead to a weakening ocean carbon uptake rate as warm water holds less dissolved CO2 and biological productivity declines. However, most Earth system models do not incorporate the impact of warming on bacterial remineralisation and rely on simplified representations of plankton ecology that do not resolve the potential impact of climate change on ecosystem structure or elemental stoichiometry. Here we use a recently-developed extension of the cGEnIE Earth system model (ecoGEnIE) featuring a trait-based scheme for 15 plankton ecology (ECOGEM), and also incorporate cGEnIE's temperature-dependent remineralisation (TDR) scheme. This enables evaluation of the impact of both ecological dynamics and temperature-dependent remineralisation on the soft-tissue biological pump in response to climate change. We find that including TDR strengthens the biological pump relative to default runs due to increased nutrient recycling, while ECOGEM weakens the biological pump by enabling a shift to smaller plankton classes.
    [Show full text]
  • Ocean Acidification and Marine Biogenic Trace Gas Production
    Ocean Acidification and Marine Biogenic Trace Gas Production A thesis submitted to the School of Environmental Sciences of the University of East Anglia in candidature for the degree of Doctor of Philosophy By Frances Elizabeth Hopkins March 2010 © This copy of the thesis has been supplied on condition that anyone who consults it is understood to recognise that its copyright rests with the author and that no quotation from the thesis, nor any information derived therefrom, may be published without the author’s prior consent. i ii Abstract The oceanic uptake of anthropogenic CO2 emissions is leading to an alteration of seawater carbonate chemistry, manifested as increasing [H+], falling [CO32-] and a drop in seawater pH. Over the coming centuries this process, termed “ocean acidification”, is expected to negatively impact marine biota, with implications for marine biological and biogeochemical processes. In this thesis, the impact that such changes may have on the net production of a range of climatically- and atmospherically-important marine biogenic trace gases, including halocarbons and dimethyl sulphide (DMS), is assessed through a mesocosm phytoplankton bloom CO2 perturbation experiment, two laboratory CO2 incubation experiments on natural seawater samples, and at a volcanically-acidified shallow marine fieldsite in Italy. Large and significant reductions in DMS and DMSP concentrations under future high CO2 conditions were observed during the mesocosm experiment (mean decreases of 57 percent and 24 percent, respectively), a finding in strong support of a previous study (Avgoustidi 2007). Furthermore, concentrations of iodocarbons showed large decreases, with mean decreases under high CO2 ranging from 59 to 93 percent.
    [Show full text]