ERIC Educational Resources Information Center
Watson, Anne
2009-01-01
The author has worked for three days on a range of mathematical tasks in order to gain a deeper understanding of the role of notation in mathematics education. The general conclusions were that while mathematical notation can be powerful it can also be obstructive. In this article, the author explores the importance on notation in supporting…
Viwattanatipa, Nita; Jermwiwatkul, Walaitip; Chintavalakorn, Rochaya; Nanthavanich, Nuntinee
2010-09-01
To analyze the survival probabilities of different surface preparation techniques for bonding brackets to nanofill composite resin. In vitro, laboratory study. Mahidol University, Bangkok, Thailand. Thirty-five nanofill composite resin specimens/group were subjected to four surface preparation techniques as follows: (1) sandblast using aluminium oxide powder of 90 microm; (2) abrasion using diamond bur; (3) hydrofluoric acid etching for 2 min; and (4) 37% orthophosphoric acid etching for 30 s. Plastic conditioner was applied then brackets were bonded. Shear bond strength tests were carried out on a universal testing machine. Shear bond strength (MPa) and debonding force (N) were analyzed using Weibull analysis. The maximum stress and debonding force levels with a 95% probability of survival ranking from highest to lowest were: (1) sandblast group (4.2 MPa, 45.5 N); (2) diamond bur group (2.2 MPa, 25.3 N); (3) orthophosphoric group (1.9 MPa, 19.8 N); and (4) hydrofluoric group (0.8 MPa, 10.9 N). There was a significant difference in the adhesive remnant index scores between the surface preparation techniques (chi squared P<0.001). Bonding orthodontic brackets to nanofill composite resin materials may result in lower bond strengths and special surface preparation techniques might be required to avoid increased numbers of bond failures. Surface treatment with sandblasting followed by plastic conditioner could increase the survival probability. The use of a diamond bur, orthophosphoric etching or hydrofluoric etching cannot be recommended.
Structural features of algebraic quantum notations
NASA Astrophysics Data System (ADS)
Gire, Elizabeth; Price, Edward
2015-12-01
[This paper is part of the Focused Collection on Upper Division Physics Courses.] The formalism of quantum mechanics includes a rich collection of representations for describing quantum systems, including functions, graphs, matrices, histograms of probabilities, and Dirac notation. The varied features of these representations affect how computations are performed. For example, identifying probabilities of measurement outcomes for a state described in Dirac notation may involve identifying expansion coefficients by inspection, but if the state is described as a function, identifying those expansion coefficients often involves performing integrals. In this study, we focus on three notational systems: Dirac notation, algebraic wave-function notation, and matrix notation. These quantum notations must include information about basis states and their associated complex probability amplitudes. In this theory paper, we identify four structural features of quantum notations, which we term individuation, degree of externalization, compactness, and symbolic support for computational rules. We illustrate how student reasoning interacts with these structural features with episodes from interviews with advanced undergraduate physics majors reasoning about a superposition state of an infinite square well system. We find evidence of the students coordinating different notations through the use of Dirac notation, using an expression in Dirac notation to guide their work in another notation. These uses are supported by the high degree of individuation, compactness, and symbolic support for computation and the moderate degree of externalization provided by Dirac notation.
Scientific Notation Watercolor
ERIC Educational Resources Information Center
Linford, Kyle; Oltman, Kathleen; Daisey, Peggy
2016-01-01
(Purpose) The purpose of this paper is to describe visual literacy, an adapted version of Visual Thinking Strategy (VTS), and an art-integrated middle school mathematics lesson about scientific notation. The intent of this lesson was to provide students with a real life use of scientific notation and exponents, and to motivate them to apply their…
ERIC Educational Resources Information Center
Leto, Frank
1996-01-01
Presenting music and notation to elementary school children exposes them to musical concepts and inspires them to take an interest in music throughout their lives. Nine lessons demonstrate how to introduce rhythmic notation to elementary-age children while utilizing percussion instruments such as timpani drums, tambourines, and rhythm sticks. (TJQ)
NASA Technical Reports Server (NTRS)
Sirlin, Samuel W.
1993-01-01
Eight-page report describes systems of notation used most commonly to represent tensors of various ranks, with emphasis on tensors in Cartesian coordinate systems. Serves as introductory or refresher text for scientists, engineers, and others familiar with basic concepts of coordinate systems, vectors, and partial derivatives. Indicial tensor, vector, dyadic, and matrix notations, and relationships among them described.
Scientific Notation Watercolor
ERIC Educational Resources Information Center
Linford, Kyle; Oltman, Kathleen; Daisey, Peggy
2016-01-01
(Purpose) The purpose of this paper is to describe visual literacy, an adapted version of Visual Thinking Strategy (VTS), and an art-integrated middle school mathematics lesson about scientific notation. The intent of this lesson was to provide students with a real life use of scientific notation and exponents, and to motivate them to apply their…
Structural Features of Algebraic Quantum Notations
ERIC Educational Resources Information Center
Gire, Elizabeth; Price, Edward
2015-01-01
The formalism of quantum mechanics includes a rich collection of representations for describing quantum systems, including functions, graphs, matrices, histograms of probabilities, and Dirac notation. The varied features of these representations affect how computations are performed. For example, identifying probabilities of measurement outcomes…
Structural Features of Algebraic Quantum Notations
ERIC Educational Resources Information Center
Gire, Elizabeth; Price, Edward
2015-01-01
The formalism of quantum mechanics includes a rich collection of representations for describing quantum systems, including functions, graphs, matrices, histograms of probabilities, and Dirac notation. The varied features of these representations affect how computations are performed. For example, identifying probabilities of measurement outcomes…
Hallucinations of musical notation.
Sacks, Oliver
2013-07-01
Hallucinations of musical notation may occur in a variety of conditions, including Charles Bonnet syndrome, Parkinson's disease, fever, intoxications, hypnagogic and hypnopompic states. Eight cases are described here, and their possible cerebral mechanisms discussed.
Sinota: A Concise Scientific Notation
ERIC Educational Resources Information Center
Butler, Crispin O.
1975-01-01
Describes a complete, convenient notation for physical quantity. Demonstrates application of this notation in problem solving, with an emphasis on pedagogy. Demonstrates the specific advantages of Sinota which derive from its simplicity and structure. (MLH)
The Mental Representation of Music Notation: Notational Audiation
ERIC Educational Resources Information Center
Brodsky, Warren; Kessler, Yoav; Rubinstein, Bat-Sheva; Ginsborg, Jane; Henik, Avishai
2008-01-01
This study investigated the mental representation of music notation. Notational audiation is the ability to internally "hear" the music one is reading before physically hearing it performed on an instrument. In earlier studies, the authors claimed that this process engages music imagery contingent on subvocal silent singing. This study refines the…
The Mental Representation of Music Notation: Notational Audiation
ERIC Educational Resources Information Center
Brodsky, Warren; Kessler, Yoav; Rubinstein, Bat-Sheva; Ginsborg, Jane; Henik, Avishai
2008-01-01
This study investigated the mental representation of music notation. Notational audiation is the ability to internally "hear" the music one is reading before physically hearing it performed on an instrument. In earlier studies, the authors claimed that this process engages music imagery contingent on subvocal silent singing. This study refines the…
Scientific Notation in Instructional Design.
ERIC Educational Resources Information Center
Boutwell, Richard C.
1978-01-01
Discusses the adoption of a notation system that is generalizable to all instructional designers and will allow and encourage a common communication base. Ten instructional design models are discussed as systems approaches to instructional design. (JEG)
Bracket for photovoltaic modules
Ciasulli, John; Jones, Jason
2014-06-24
Brackets for photovoltaic ("PV") modules are described. In one embodiment, a saddle bracket has a mounting surface to support one or more PV modules over a tube, a gusset coupled to the mounting surface, and a mounting feature coupled to the gusset to couple to the tube. The gusset can have a first leg and a second leg extending at an angle relative to the mounting surface. Saddle brackets can be coupled to a torque tube at predetermined locations. PV modules can be coupled to the saddle brackets. The mounting feature can be coupled to the first gusset and configured to stand the one or more PV modules off the tube.
The mental representation of music notation: notational audiation.
Brodsky, Warren; Kessler, Yoav; Rubinstein, Bat-Sheva; Ginsborg, Jane; Henik, Avishai
2008-04-01
This study investigated the mental representation of music notation. Notational audiation is the ability to internally "hear" the music one is reading before physically hearing it performed on an instrument. In earlier studies, the authors claimed that this process engages music imagery contingent on subvocal silent singing. This study refines the previously developed embedded melody task and further explores the phonatory nature of notational audiation with throat-audio and larynx-electromyography measurement. Experiment 1 corroborates previous findings and confirms that notational audiation is a process engaging kinesthetic-like covert excitation of the vocal folds linked to phonatory resources. Experiment 2 explores whether covert rehearsal with the mind's voice also involves actual motor processing systems and suggests that the mental representation of music notation cues manual motor imagery. Experiment 3 verifies findings of both Experiments 1 and 2 with a sample of professional drummers. The study points to the profound reliance on phonatory and manual motor processing--a dual-route stratagem--used during music reading. Further implications concern the integration of auditory and motor imagery in the brain and cross-modal encoding of a unisensory input. (Copyright) 2008 APA, all rights reserved.
Flexible Envelope Request Notation (FERN)
NASA Technical Reports Server (NTRS)
Zoch, David R.; Lavallee, David; Weinstein, Stuart
1991-01-01
The following topics are presented in view graph form and include the following: scheduling application; the motivation for the Flexible Envelope Request Notation (FERN); characteristics of FERN; types of information needed in requests; where information is stored in requests; FERN structures; generic requests; resource availability for pooled resources; expressive notation; temporal constraints; time formats; changes to FERN; sample FERN requests; the temporal relationship between two steps; maximum activity length to limit step delays; alternative requests; the temporal relationship between two activities; and idle resource usage between steps.
The Systems Biology Graphical Notation.
Le Novère, Nicolas; Hucka, Michael; Mi, Huaiyu; Moodie, Stuart; Schreiber, Falk; Sorokin, Anatoly; Demir, Emek; Wegner, Katja; Aladjem, Mirit I; Wimalaratne, Sarala M; Bergman, Frank T; Gauges, Ralph; Ghazal, Peter; Kawaji, Hideya; Li, Lu; Matsuoka, Yukiko; Villéger, Alice; Boyd, Sarah E; Calzone, Laurence; Courtot, Melanie; Dogrusoz, Ugur; Freeman, Tom C; Funahashi, Akira; Ghosh, Samik; Jouraku, Akiya; Kim, Sohyoung; Kolpakov, Fedor; Luna, Augustin; Sahle, Sven; Schmidt, Esther; Watterson, Steven; Wu, Guanming; Goryanin, Igor; Kell, Douglas B; Sander, Chris; Sauro, Herbert; Snoep, Jacky L; Kohn, Kurt; Kitano, Hiroaki
2009-08-01
Circuit diagrams and Unified Modeling Language diagrams are just two examples of standard visual languages that help accelerate work by promoting regularity, removing ambiguity and enabling software tool support for communication of complex information. Ironically, despite having one of the highest ratios of graphical to textual information, biology still lacks standard graphical notations. The recent deluge of biological knowledge makes addressing this deficit a pressing concern. Toward this goal, we present the Systems Biology Graphical Notation (SBGN), a visual language developed by a community of biochemists, modelers and computer scientists. SBGN consists of three complementary languages: process diagram, entity relationship diagram and activity flow diagram. Together they enable scientists to represent networks of biochemical interactions in a standard, unambiguous way. We believe that SBGN will foster efficient and accurate representation, visualization, storage, exchange and reuse of information on all kinds of biological knowledge, from gene regulation, to metabolism, to cellular signaling.
Optical pattern recognition for printed music notation
NASA Astrophysics Data System (ADS)
Homenda, Wladyslaw
1995-03-01
The paper presents problems related to automated recognition of printed music notation. Music notation recognition is a challenging problem in both fields: pattern recognition and knowledge representation. Music notation symbols, though well characterized by their features, are arranged in elaborated way in real music notation, which makes recognition task very difficult and still open for new ideas. On the other hand, the aim of the system, i.e. application of acquired printed music into further processing requires special representation of music data. Due to complexity of music nature and music notation, music representation is one of the key issue in music notation recognition and music processing. The problems of pattern recognition and knowledge representation in context or music processing are discussed in this paper. MIDISCAN, the computer system for music notation recognition and music processing, is presented.
LETS: An Expressional Loop Notation.
1982-10-01
r - ..’ -rI- x- - r ,11 V~ The Expressional Metaphor 2- Waters i "The Expressional Metaphor ’lhe key property of expressions which makes them...development of a notation which has the property of decomposability. Viewing Loops as Expressions Involving Sequences In order to represent loops as...a DEFUNS or LETS. For example, the function EPLIST takes in a discnbodied plist and returns two values: a sequence of the property names. and a
An ex vivo assessment of gingivally offset lower premolar brackets.
Thind, B S; Larmour, C J; Stirrups, D R; Lloyd, C H
2004-03-01
To compare the force to failure of standard premolar brackets to that of gingivally offset brackets and evaluate the site of bond failure between the two bracket types through the use of the Adhesive Remnant Index (ARI). An ex vivo study. Dental Materials Science Laboratory, Dundee Dental School, Dundee. Forty extracted lower premolar teeth (caries free, extracted as part of orthodontic treatment, all donors living in a non-fluoridated area), divided into two equal size sample groups, as follows: Group 1: Victory Series (3M Unitek, Monrovia CA, USA) lower premolar brackets bonded to buccal surfaces with Transbond XT (3M Unitek, Monrovia CA). Group 2: Victory Series Gingivally Offset Bicuspid Brackets (3M Unitek, Monrovia CA) bonded to buccal surfaces with Transbond XT (3M Unitek, Monrovia CA). Force was applied in the occluso-gingival direction using an Instron Model 4469 Universal Testing Machine (Instron Ltd, High Wycombe, UK) operating at a cross-head speed of 0.5 mm/min and its value at failure determined. Following debond, the site of bond failure and ARI were recorded. Force to failure, site of bond failure and adhesive remnant index. The Weibull analysis gave higher values for the force to failure at 5% level (200 v. 159 N) and at all other levels of probability of failure for the gingivally offset bracket. The non-parametric survival analysis using Gehan-Wilcoxon tests with Breslow's algorithm (p < 0.0001) showed significant difference in force to failure between bracket types. Chi-square tests showed no significant (p = 0.55) relationship between the site of bond failure and the bracket types. Ex vivo testing suggests that there is a significant difference in the force to failure between gingivally offset and standard lower premolar brackets when force application is from an occluso-gingival direction. The site of failure (as given by the ARI) is insensitive to bracket types and force to failure.
Across-Notation Automatic Numerical Processing
ERIC Educational Resources Information Center
Ganor-Stern, Dana; Tzelgov, Joseph
2008-01-01
In this article, the authors explored the existence of across-notation automatic numerical processing using size comparison and same-different paradigms. Participants were Arabic speakers, who used 2 sets of numerical symbols--Arabic and Indian. They were presented with number pairs in the same notation (Arabic or Indian) or in different ones…
Code of Federal Regulations, 2012 CFR
2012-07-01
... UNITED STATES POSTAL SERVICE THE BOARD OF GOVERNORS OF THE U.S. POSTAL SERVICE MEETINGS (ARTICLE VI) § 6.... Notation voting may be used only for routine, non-controversial, and administrative matters. (b... use of notation voting for the consideration of any matter. If a Board member vetoes the use of...
Structured programming: Principles, notation, procedure
NASA Technical Reports Server (NTRS)
JOST
1978-01-01
Structured programs are best represented using a notation which gives a clear representation of the block encapsulation. In this report, a set of symbols which can be used until binding directives are republished is suggested. Structured programming also allows a new method of procedure for design and testing. Programs can be designed top down, that is, they can start at the highest program plane and can penetrate to the lowest plane by step-wise refinements. The testing methodology also is adapted to this procedure. First, the highest program plane is tested, and the programs which are not yet finished in the next lower plane are represented by so-called dummies. They are gradually replaced by the real programs.
Experience with abstract notation one
NASA Technical Reports Server (NTRS)
Harvey, James D.; Weaver, Alfred C.
1990-01-01
The development of computer science has produced a vast number of machine architectures, programming languages, and compiler technologies. The cross product of these three characteristics defines the spectrum of previous and present data representation methodologies. With regard to computer networks, the uniqueness of these methodologies presents an obstacle when disparate host environments are to be interconnected. Interoperability within a heterogeneous network relies upon the establishment of data representation commonality. The International Standards Organization (ISO) is currently developing the abstract syntax notation one standard (ASN.1) and the basic encoding rules standard (BER) that collectively address this problem. When used within the presentation layer of the open systems interconnection reference model, these two standards provide the data representation commonality required to facilitate interoperability. The details of a compiler that was built to automate the use of ASN.1 and BER are described. From this experience, insights into both standards are given and potential problems relating to this development effort are discussed.
[Polar and non polar notations of refraction].
Touzeau, O; Gaujoux, T; Costantini, E; Borderie, V; Laroche, L
2010-01-01
Refraction can be expressed by four polar notations which correspond to four different combinations of spherical or cylindrical lenses. Conventional expressions of refraction (plus and minus cylinder notation) are described by sphere, cylinder, and axis. In the plus cylinder notation, the axis visualizes the most powerful meridian. The axis usually corresponds to the bow tie axis in curvature maps. Plus cylinder notation is also valuable for all relaxing procedures (i.e., selective suture ablation, arcuate keratotomy, etc.). In the cross-cylinder notation, two orthogonal cylinders can describe (without the sphere component) the actual refraction of both the principal meridians. This notation must be made before performing the vertex calculation. Using an association of a Jackson cross-cylinder and a spherical equivalent, refraction can be broken down into two pure components: astigmatism and sphere. All polar notations of refraction may perfectly characterize a single refraction but are not suitable for statistical analysis, which requires nonpolar expression. After doubling the axis, a rectangular projection breaks down the Jackson cross-cylinder, which has a polar axis, into two Jackson cross-cylinders on the 0 degrees /90 degrees and 45 degrees /135 degrees axis. This procedure results in the loss of the directional nature of the data. Refraction can be written in a nonpolar notation by three rectangular coordinates (x,y,z), which can also represent the spherocylinder by one point in a dioptric space. These three independent (orthogonal) variables have a concrete optical significance: a spherical component, a direct/inverse (WTR/ATR) component, and an oblique component of the astigmatism. Finally, nonpolar notations are useful for statistical analysis and graphical representation of refraction.
Aztec arithmetic: positional notation and area calculation.
Harvey, H R; Williams, B J
1980-10-31
Texcocan-Aztec peoples in the Valley of Mexico used both picture symbols and lines and dots for numerical notation. Decipherment and analysis of mid-16th-century native pictorial land documents from the Texcocan region indicate that the line-and-dot system incorporated a symbol for zero and used position to ascribe values. Positional line-and-dot notation was used to record areas of agricultural fields, and analysis of the documentary data suggests that areas were calculated arithmetically. These findings demonstrate that neither positional notation nor the zero were unique to the Maya area, and they imply an equally sophisticated mathematical development among the Aztecs.
Biochemical modeling with Systems Biology Graphical Notation.
Jansson, Andreas; Jirstrand, Mats
2010-05-01
The Systems Biology Graphical Notation (SBGN) is an emerging standard for graphical notation developed by an international systems biology community. Standardized graphical notation is crucial for efficient and accurate communication of biological knowledge between researchers with various backgrounds in the expanding field of systems biology. Here, we highlight SBGN from a practical point of view and describe how the user can build and simulate SBGN models from a simple drag-and-drop graphical user interface in PathwayLab. Copyright 2010 Elsevier Ltd. All rights reserved.
Kauffman bracket of plane curves
NASA Astrophysics Data System (ADS)
Chmutov, S.; Goryunov, V.
1996-12-01
We lower the Kauffman bracket for links in a solid torus (see [16]) to generic plane fronts. It turns out that the bracket can be entirely defined in terms of a front itself without using the Legendrian lifting. We show that all the coefficients of the lowered bracket are in fact Vassilev type invariants of Arnold's J +-theory [3, 4]. We calculate their weight systems. As a corollary we obtain that the first coefficient is essentially the quantum deformation of the Bennequin invariant introduced recently by M. Polyak [19].
Methods of debonding ceramic brackets.
Winchester, L
1992-08-01
The problem of debonding ceramic brackets is still one which concerns the orthodontist. It is advisable to use the manufacturers recommended method of debonding each particular type of bracket. The risks of using such brackets need to be carefully assessed against the benefits. Risks can be minimized by carefully assessing the patient and the dentition, avoiding heavily restored teeth with pre-existing enamel cracks. It would seem wise to obtain an informed consent from the patient having out-lined the potential problems.
Symbolic Notations and Students' Achievements in Algebra
ERIC Educational Resources Information Center
Peter, Ebiendele E.; Olaoye, Adetunji A.
2013-01-01
This study focuses on symbolic notations and its impact on students' achievement in Algebra. The main reason for this study rests on the observation from personal and professional experiences on students' increasing hatred for Algebra. One hundred and fifty (150) Senior Secondary School Students (SSS) from Ojo Local Education District, Ojo, Lagos,…
Japanese Children's Understanding of Notational Systems
ERIC Educational Resources Information Center
Takahashi, Noboru
2012-01-01
This study examined Japanese children's understanding of two Japanese notational systems: "hiragana" and "kanji". In three experiments, 126 3- to 6-year-olds were asked to name words written in hiragana or kanji as they appeared with different pictures. Consistent with Bialystok ("Journal of Experimental Child…
Symbolic Notations and Students' Achievements in Algebra
ERIC Educational Resources Information Center
Peter, Ebiendele E.; Olaoye, Adetunji A.
2013-01-01
This study focuses on symbolic notations and its impact on students' achievement in Algebra. The main reason for this study rests on the observation from personal and professional experiences on students' increasing hatred for Algebra. One hundred and fifty (150) Senior Secondary School Students (SSS) from Ojo Local Education District, Ojo, Lagos,…
Japanese Children's Understanding of Notational Systems
ERIC Educational Resources Information Center
Takahashi, Noboru
2012-01-01
This study examined Japanese children's understanding of two Japanese notational systems: "hiragana" and "kanji". In three experiments, 126 3- to 6-year-olds were asked to name words written in hiragana or kanji as they appeared with different pictures. Consistent with Bialystok ("Journal of Experimental Child…
Ceramic bracket debonding with Tm:fiber laser
NASA Astrophysics Data System (ADS)
Demirkan, İrem; Sarp, Ayşe Sena Kabaş; Gülsoy, Murat
2016-06-01
Lasers have the potential for reducing the required debonding force and can prevent the mechanical damage given to the enamel surface as a result of conventional debonding procedure. However, excessive thermal effects limit the use of lasers for debonding purposes. The aim of this study was to investigate the optimal parameters of 1940-nm Tm:fiber laser for debonding ceramic brackets. Pulling force and intrapulpal temperature measurements were done during laser irradiation simultaneously. A laser beam was delivered in two different modes: scanning the fiber tip on the bracket surface with a Z shape movement or direct application of the fiber tip at one point in the center of the bracket. Results showed that debonding force could be decreased significantly compared to the control samples, in which brackets were debonded by only mechanical force. Intrapulpal temperature was kept equal or under the 5.5°C threshold value of probable thermal damage to pulp. Scanning was found to have no extra contribution to the process. It was concluded that using 1940-nm Tm:fiber laser would facilitate the debonding of ceramic brackets and can be proposed as a promising debonding tool with all the advantageous aspects of fiber lasers.
[SIBSytem: innovation for bracket bonding?].
Moreau, Alexis
2013-06-01
The orthodontic bracket placement has known two major improvements these last fifty years: first with the ability of bonding brackets directly on the enamel (Newmann 1965); second with the indirect bonding procedure introduced by Silvermann and Cohen in 1972. If we put aside the technological evolutions of bonding materials (brackets and adhesives), few refinements have occurred regarding the protocols in this period of time. Furthermore, direct bonding procedure seems to be used by a majority of orthodontists despite the rapidity, accuracy and ergonomics promised by indirect bonding protocol. The main originality of the system detailed in this article is to bond orthodontic brackets in a virtually predetermined position with indirect bonding advantages but with the efficiency of direct bonding because the adhesive is applied directly on the bracket base without pre-bonding necessity. This innovation has been allowed by the use of up-to-date CFAO technology. The article first describes the two components of the SIBSystem (SIBClip and SIBTray) and details the manufacturing stages. The clinical use is then evoked as well as the cautions and limits of this innovative bonding system.
30 CFR 75.1202 - Temporary notations, revisions, and supplements.
Code of Federal Regulations, 2014 CFR
2014-07-01
... COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Maps § 75.1202 Temporary notations, revisions, and supplements. Such map shall be kept up-to-date by temporary notations and such map...
30 CFR 75.1202 - Temporary notations, revisions, and supplements.
Code of Federal Regulations, 2011 CFR
2011-07-01
... COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Maps § 75.1202 Temporary notations, revisions, and supplements. Such map shall be kept up-to-date by temporary notations and such map...
30 CFR 75.1202 - Temporary notations, revisions, and supplements.
Code of Federal Regulations, 2012 CFR
2012-07-01
... COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Maps § 75.1202 Temporary notations, revisions, and supplements. Such map shall be kept up-to-date by temporary notations and such map...
30 CFR 75.1202 - Temporary notations, revisions, and supplements.
Code of Federal Regulations, 2013 CFR
2013-07-01
... COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Maps § 75.1202 Temporary notations, revisions, and supplements. Such map shall be kept up-to-date by temporary notations and such map...
30 CFR 75.1202 - Temporary notations, revisions, and supplements.
Code of Federal Regulations, 2010 CFR
2010-07-01
... COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Maps § 75.1202 Temporary notations, revisions, and supplements. Such map shall be kept up-to-date by temporary notations and such map...
Improvements in bracket base design.
Smith, D C; Maijer, R
1983-04-01
Acid etch bonding of orthodontic attachments to the labial and lingual surfaces of teeth is generally adequate for clinical service. Failures do occur, and these are related to technique problems in acid etching or resin manipulation or to bracket base design. The widely used foil mesh base can present problems in retention because of design defects or corrosion. Improvement in mechanical retention of resin to the attachment base would result in significant improvements in bonding and fewer clinical failures. One of our approaches to improved retention is to fuse metallic or ceramic particles onto the bracket base so as to achieve a particulate or porous layer into which resin can penetrate. The results of bond-strength tests showed that a 100 percent increase in bond strength could be obtained with sintered porous metal-coated brackets. Further development is proceeding.
Corrosion of orthodontic bracket bases.
Maijer, R; Smith, D C
1982-01-01
Attention has recently been focused on the development of black and green stains in association with directly bonded stainless steel brackets. Twelve clinical cases of staining were studied in this investigation. After intraoral photography of the stains, the brackets were removed for examination with the scanning electron microscope. Multiple voids were observed at the resin-bracket interface, especially at the periphery. Considerable deterioration of the alloy base and mesh structure was observed in the void areas. Preliminary analysis of the stains showed that chromium compounds were present. The findings suggested that the presence of voids, together with poor oral hygiene, led to crevice corrosion of the Type 304 stainless steel and formation of colored corrosion products which can result in enamel stains. The use of stainless steels of improved corrosion resistance is recommended to overcome this problem.
Sound Foundations: Organic Approaches to Learning Notation in Beginning Band
ERIC Educational Resources Information Center
West, Chad
2016-01-01
By starting with a foundation of sound before sight, we can help our students learn notation organically in a way that honors the natural process. This article describes five organic approaches to learning notation in beginning band: (1) iconic notation, (2) point and play, (3) student lead-sheet, (4) modeling, and (5) kid dictation. While…
Sound Foundations: Organic Approaches to Learning Notation in Beginning Band
ERIC Educational Resources Information Center
West, Chad
2016-01-01
By starting with a foundation of sound before sight, we can help our students learn notation organically in a way that honors the natural process. This article describes five organic approaches to learning notation in beginning band: (1) iconic notation, (2) point and play, (3) student lead-sheet, (4) modeling, and (5) kid dictation. While…
Structural support bracket for gas flow path
2016-08-02
A structural support system is provided in a can annular gas turbine engine having an arrangement including a plurality of integrated exit pieces (IEPs) forming an annular chamber for delivering gases from a plurality of combustors to a first row of turbine blades. A bracket structure is connected between an IEP and an inner support structure on the engine. The bracket structure includes an axial bracket member attached to an IEP and extending axially in a forward direction. A transverse bracket member has an end attached to the inner support structure and extends circumferentially to a connection with a forward end of the axial bracket member. The transverse bracket member provides a fixed radial position for the forward end of the axial bracket member and is flexible in the axial direction to permit axial movement of the axial bracket member.
Singularly Perturbed Lie Bracket Approximation
Durr, Hans-Bernd; Krstic, Miroslav; Scheinker, Alexander; Ebenbauer, Christian
2015-03-27
Here, we consider the interconnection of two dynamical systems where one has an input-affine vector field. We show that by employing a singular perturbation analysis and the Lie bracket approximation technique, the stability of the overall system can be analyzed by regarding the stability properties of two reduced, uncoupled systems.
Japanese children's understanding of notational systems.
Takahashi, Noboru
2012-12-01
This study examined Japanese children's understanding of two Japanese notational systems: hiragana and kanji. In three experiments, 126 3- to 6-year-olds were asked to name words written in hiragana or kanji as they appeared with different pictures. Consistent with Bialystok (Journal of Experimental Child Psychology, 2000, Vol. 76, pp. 173-189), 3- and 4-year-olds' identification of written words varied according to the picture with which they appeared, and older children named the words with different pictures more accurately. The 4-year-olds who could read words written in hiragana but could not read words written in kanji named both hiragana words and kanji words with different pictures more accurately than those who could not read hiragana and kanji words. The interrelationship between the symbol-sound relationships and the symbol-referent relationships of notational systems is discussed. Copyright © 2012 Elsevier Inc. All rights reserved.
Homer, R Webster; Swanson, Jon; Jilek, Robert J; Hurst, Tad; Clark, Robert D
2008-12-01
SYBYL line notation (SLN) is a powerful way to represent molecular structures, reactions, libraries of structures, molecular fragments, formulations, molecular queries, and reaction queries. Nearly any chemical structure imaginable, including macromolecules, pharmaceuticals, catalysts, and even combinatorial libraries can be represented as an SLN string. The language provides a rich syntax for database queries comparable to SMARTS. It provides full Markush, R-Group, reaction, and macro atom capabilities in a single unified notation. It includes the ability to specify 3D conformations and 2D depictions. All the information necessary to recreate the structure in a modeling or drawing package is present in a single, concise string of ASCII characters. This makes SLN ideal for structure communication over global computer networks between applications sitting at remote sites. Unlike SMILES and its derivatives, SLN accomplishes this within a single unified syntax. Structures, queries, compounds, reactions, and virtual libraries can all be represented in a single notation.
Adhesive performance of precoated brackets after expiration.
Cloud, Cayce C; Trojan, Terry M; Suliman, Sam N; Tantbirojn, Daranee; Versluis, Antheunis
2016-03-01
To evaluate adhesive performance in terms of debonding forces of precoated metal and ceramic brackets 4 years after expiration. Buccal and lingual surfaces of embedded extracted maxillary premolars were etched with 34% Tooth Conditioner Gel (Dentsply Caulk, Milford, Del), rinsed, and dried. Transbond MIP (3M Unitek, Monrovia, Calif) was applied prior to placing adhesive precoated brackets (APC II Victory stainless steel and APC Plus Clarity ceramic brackets, 3M Unitek). The preexpiration brackets had 29-35 months before, and the postexpiration brackets were 45-52 months past, their expiration dates. Sample size was 17-21 per group. Debonding forces were determined by subjecting the bonded brackets to a shear force in a universal testing machine. Debonding forces were compared using two-way ANOVA. Debonded surfaces were examined under a stereomicroscope to determine failure modes, which were compared using the chi-square test. No statistically significant difference was found in debonding forces (P = .8581) or failure modes (P = .4538) between expired and unexpired brackets. Metal brackets required statistically significantly higher debonding forces than did ceramic brackets (P = .0001). For both expired and unexpired brackets, failure modes were mostly cohesive in the adhesive layer for ceramic brackets, and mixed between adhesive and cohesive failure in the adhesive layer for metal brackets. Adhesive precoated brackets did not have any reduction in enamel-adhesion properties up to 4 years after their expiration date. Extended shelf life testing for precoated dental brackets may be worth considering.
Effect of delayed polymerization time and bracket manipulation on orthodontic bracket bonding
NASA Astrophysics Data System (ADS)
Ponikvar, Michael J.
This study examined the effect of bracket manipulation in combination with delayed polymerization times on orthodontic bracket shear bond strength and degree of resin composite conversion. Orthodontics brackets were bonded to extracted third molars in a simulated oral environment after a set period of delayed polymerization time and bracket manipulation. After curing the bracket adhesive, each bracket underwent shear bond strength testing followed by micro-Raman spectroscopy analysis to measure the degree of conversion of the resin composite. Results demonstrated the shear bond strength and the degree of conversion of ceramic brackets did not vary over time. However, with stainless steel brackets there was a significant effect (p ≤ 0.05) of delay time on shear bond strength between the 0.5 min and 10 min bracket groups. In addition, stainless steel brackets showed significant differences related to degree of conversion over time between the 0.5 min and 5 min groups, in addition to the 0.5 min and 10 min groups. This investigation suggests that delaying bracket adhesive polymerization up to a period of 10 min then adjusting the orthodontic bracket may increase both shear bond strength and degree of conversion of stainless steel brackets while having no effect on ceramic brackets.
The Role of Number Notation: Sign-Value Notation Number Processing is Easier than Place-Value.
Krajcsi, Attila; Szabó, Eszter
2012-01-01
Number notations can influence the way numbers are handled in computations; however, the role of notation itself in mental processing has not been examined directly. From a mathematical point of view, it is believed that place-value number notation systems, such as the Indo-Arabic numbers, are superior to sign-value systems, such as the Roman numbers. However, sign-value notation might have sufficient efficiency; for example, sign-value notations were common in flourishing cultures, such as in ancient Egypt. Herein we compared artificial sign-value and place-value notations in simple numerical tasks. We found that, contrary to the dominant view, sign-value notation can be applied more easily than place-value notation for multi-power comparison and addition tasks. Our results are consistent with the popularity of sign-value notations that prevailed for centuries. To explain the notation effect, we propose a natural multi-power number representation based on the numerical representation of objects.
Bracket relations for relativity groups
NASA Astrophysics Data System (ADS)
Jordan, Thomas F.
2016-11-01
Poisson bracket relations for generators of canonical transformations are derived directly from the Galilei and Poincaré groups of space-time coordinate changes. The method is simple but rigorous. The meaning of each step is clear, because it corresponds to an operation in the group of changes of space-time coordinates. Only products and inverses are used; differences are not used. It is made explicitly clear why constants occur in some bracket relations but not in others and how some constants can be removed, so that in the end there is a constant in the bracket relations for the Galilei group but not for the Poincaré group. Each change of coordinates needs to be only to first order, so matrices are not needed for rotations or Lorentz transformations; simple three-vector descriptions are enough. Conversion to quantum mechanics is immediate. One result is a simpler derivation of the commutation relations for angular momentum directly from rotations. Problems are included.
Conditional Independence in Applied Probability.
ERIC Educational Resources Information Center
Pfeiffer, Paul E.
This material assumes the user has the background provided by a good undergraduate course in applied probability. It is felt that introductory courses in calculus, linear algebra, and perhaps some differential equations should provide the requisite experience and proficiency with mathematical concepts, notation, and argument. The document is…
Material testing of reconditioned orthodontic brackets.
Reimann, S; Rewari, A; Keilig, L; Widu, F; Jäger, A; Bourauel, C
2012-12-01
While all manufacturers of orthodontic brackets label these products for single use, there are commercial providers offering bracket reconditioning (or "recycling"). We conducted this study to investigate the effects of different recycling techniques on material-related parameters in orthodontic brackets, aiming to derive indications for clinical use and conclusions about the biocompatibility, longevity, and application of recycled brackets. New metal brackets (equilibrium(®); Dentaurum, Ispringen, Germany) were compared to brackets recycled by different techniques, including direct flaming with a Bunsen burner, chemical reconditioning in an acid bath, a commercial unit (Big Jane; Esmadent, IL, USA), and outsourcing to a company (Ortho Clean, Dellstedt, Germany). Material-related examinations included the following: (1) corrosion behavior by static immersion testing and use of a mass spectrometer to determine nickel-ion concentrations in the corrosive medium, (2) surface features in scanning electron micrographs before and after corrosion testing, (3) Vickers hardness using a hardness testing machine, (4) shear bond strength as defined in DIN 13990-1, (5) dimensional stability of the bracket slots by light microscopy, and (6) frictional loss as assessed by an orthodontic measurement and simulation system (OMSS). Each examination was performed on ten brackets. Student's t-test was used for statistical analysis. Compared to the new brackets, those recycled in an acid bath or by a commercial provider revealed significant dimensional changes (p<0.05). Corrosion on the recycled brackets varied according to the recycling techniques employed. The group of brackets recycled by one company revealed hardness values that differed from those of all the other groups. No significant differences were observed in nickel-ion release, frictional loss, and shear bond strength. Recycling was found to significantly reduce the corrosion resistance and dimensional stability of
Theories of Notation and Polar Motion I,
1980-12-01
attraction 2 on expanding 1,/i into a series of Legendre polynomials P (cos ) ( Heiskanen and Moritz, 1967, p. 33). The notations are evident from Fig...harmonics ( Heiskanen and Moritz, 1967, p. 33), and we obtain 3 FIG. 1.2. Coordinates of P and of the moon. V) + V1’ ( 2 1-3) with the zonal part vg=Gu A L...ea:I a c- -, (1 c jr -I moon K ’p - 1--la 29 the earth, which for, rotational s mer, tjl tini e,, - known form V= 1C a 0 co. . r ’f. Heiskanen arid r
Thermal debracketing of single crystal sapphire brackets.
Rueggeberg, F A; Lockwood, P E
1992-01-01
Because of their optical clarity, single crystal sapphire brackets provide an esthetic advantage over many other types of orthodontic brackets. However, debonding of these brackets has caused iatrogenic damage to enamel. Thermal debonding has been proposed for use in removing sapphire brackets without causing damage to teeth. This study determined the temperature required at the enamel/resin interface to thermally debond sapphire brackets from etched bovine enamel using 23 different commercially available orthodontic resins and one experimental product. The results indicate a wide range of debonding temperatures for the various resins. As a group, the powder-liquid materials had a statistically lower debonding temperature than the two-paste, the no-mix products, or the light-cured materials, for which the temperatures were all similar. This paper presents relative information a clinician can use in selecting an orthodontic bonding resin to minimize thermal damage to the teeth while debonding sapphire brackets.
The 2008 ICOH Workshop on Skin Notation.
Sartorelli, P; Ahlers, H W; Cherrie, J W; Kezic, Sanja; Johanson, G; Filon, Francesca Larese; Nielsen, J B; Shepherd, A; Stull, J; Williams, Faith
2010-01-01
On 29 March 2008 the International Commission on Occupational Health (ICOH) Scientific Committee on Occupational and Environmental Dermatoses organized a Skin Notation Workshop hosted by the 11th International Percutaneous Penetration Perspectives Conference (La Grande Motte, France). Skin notation (S) was chosen as a topic for discussion because this is the only example of existing regulation in the field of dermal risk assessment. The issue was discussed in a previous workshop held in Siena, Italy in 2006 with the objective of focussing on the problems related to S, the different assignment criteria and the attempts to improve the S system made by various international and governmental agencies. A position paper was subsequently published. The workshop in France was a continuation of this activity with the aim of evaluating how the different strategies can improve S. The Workshop was divided into two sessions. The first was dedicated to lectures focused on different aspects of S. In the second session participants discussed key issues with the aim of exploring the actions needed to improve international S. systems.
Three-dimensional deformation of orthodontic brackets
Melenka, Garrett W; Nobes, David S; Major, Paul W
2013-01-01
Braces are used by orthodontists to correct the misalignment of teeth in the mouth. Archwire rotation is a particular procedure used to correct tooth inclination. Wire rotation can result in deformation to the orthodontic brackets, and an orthodontic torque simulator has been designed to examine this wire–bracket interaction. An optical technique has been employed to measure the deformation due to size and geometric constraints of the orthodontic brackets. Images of orthodontic brackets are collected using a stereo microscope and two charge-coupled device cameras, and deformation of orthodontic brackets is measured using a three-dimensional digital image correlation technique. The three-dimensional deformation of orthodontic brackets will be evaluated. The repeatability of the three-dimensional digital image correlation measurement method was evaluated by performing 30 archwire rotation tests using the same bracket and archwire. Finally, five Damon 3MX and five In-Ovation R self-ligating brackets will be compared using this technique to demonstrate the effect of archwire rotation on bracket design. PMID:23762201
Al-Thomali, Yousef; Mohamed, Roshan-Noor; Basha, Sakeenabi
2017-01-01
Background To evaluate the torque expression of self ligating (SL) orthodontic brackets and conventionally ligated brackets and the torque expression in active and passive SL brackets. Material and Methods Our systematic search included MEDLINE, EMBASE, CINAHL, PsychINFO, Scopus, and key journals and review articles; the date of the last search was April 4th 2016. We graded the methodological quality of the studies by means of the Quality Assessment Tool for Quantitative Studies, developed for the Effective Public Health Practice Project (EPHPP). Results In total, 87 studies were identified for screening, and 9 studies were eligible. The quality assessment rated one of the study as being of strong quality, 7 (77.78%) of these studies as being of moderate quality. Three out of 7 studies which compared SL and conventionally ligated brackets showed, conventionally ligated brackets with highest torque expression compared to SL brackets. Badawi showed active SL brackets with highest torque expression compared to passive SL brackets. Major and Brauchli showed no significant differences in torque expression of active and passive SL brackets. Conclusions Conventionally ligated brackets presented with highest torque expression compared to SL brackets. Minor difference was recorded in a torque expression of active and passive SL brackets. Key words:Systematic review, self ligation, torque expression, conventional ligation. PMID:28149476
Symbolic algorithms for the computation of Moshinsky brackets and nuclear matrix elements
NASA Astrophysics Data System (ADS)
Ursescu, D.; Tomaselli, M.; Kuehl, T.; Fritzsche, S.
2005-12-01
To facilitate the use of the extended nuclear shell model (NSM), a FERMI module for calculating some of its basic quantities in the framework of MAPLE is provided. The Moshinsky brackets, the matrix elements for several central and non-central interactions between nuclear two-particle states as well as their expansion in terms of Talmi integrals are easily given within a symbolic formulation. All of these quantities are available for interactive work. Program summaryTitle of program:Fermi Catalogue identifier:ADVO Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADVO Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Licensing provisions:None Computer for which the program is designed and others on which is has been tested:All computers with a licence for the computer algebra package MAPLE [Maple is a registered trademark of Waterloo Maple Inc., produced by MapleSoft division of Waterloo Maple Inc.] Instalations:GSI-Darmstadt; University of Kassel (Germany) Operating systems or monitors under which the program has beentested: WindowsXP, Linux 2.4 Programming language used:MAPLE 8 and 9.5 from MapleSoft division of Waterloo Maple Inc. Memory required to execute with typical data:30 MB No. of lines in distributed program including test data etc.:5742 No. of bytes in distributed program including test data etc.:288 939 Distribution program:tar.gz Nature of the physical problem:In order to perform calculations within the nuclear shell model (NSM), a quick and reliable access to the nuclear matrix elements is required. These matrix elements, which arise from various types of forces among the nucleons, can be calculated using Moshinsky's transformation brackets between relative and center-of-mass coordinates [T.A. Brody, M. Moshinsky, Tables of Transformation Brackets, Monografias del Instituto de Fisica, Universidad Nacional Autonoma de Mexico, 1960] and by the proper use of the nuclear states in different coupling notations
Speechant: A Vowel Notation System to Teach English Pronunciation
ERIC Educational Resources Information Center
dos Reis, Jorge; Hazan, Valerie
2012-01-01
This paper introduces a new vowel notation system aimed at aiding the teaching of English pronunciation. This notation system, designed as an enhancement to orthographic text, was designed to use concepts borrowed from the representation of musical notes and is also linked to the acoustic characteristics of vowel sounds. Vowel timbre is…
A Notation for Rapid Specification of Information Visualization
ERIC Educational Resources Information Center
Lee, Sang Yun
2013-01-01
This thesis describes a notation for rapid specification of information visualization, which can be used as a theoretical framework of integrating various types of information visualization, and its applications at a conceptual level. The notation is devised to codify the major characteristics of data/visual structures in conventionally-used…
Self-Invented Notation Systems Created by Young Children
ERIC Educational Resources Information Center
Lee, Pyng-Na
2013-01-01
This longitudinal study investigated self-invented notation systems created by young children aged four to six. The researcher showed the children how to feel various pitches and rhythms through singing, eurhythmy, instrumental playing, rhymes and music appreciation. The children were then provided with opportunities to create music notations and…
Representing Fractions with Standard Notation: A Developmental Analysis
ERIC Educational Resources Information Center
Saxe, Geoffrey B.; Taylor, Edd V.; McIntosh, Clifton; Gearhart, Maryl
2005-01-01
This study had two purposes: (a) to investigate the developmental relationship between students' uses of fractions notation and their understandings of part-whole relations; and (b) to produce an analysis of the role of fractions instruction in students' use of notation to represent parts of an area. Elementary students (n = 384) in 19 classes…
Speechant: A Vowel Notation System to Teach English Pronunciation
ERIC Educational Resources Information Center
dos Reis, Jorge; Hazan, Valerie
2012-01-01
This paper introduces a new vowel notation system aimed at aiding the teaching of English pronunciation. This notation system, designed as an enhancement to orthographic text, was designed to use concepts borrowed from the representation of musical notes and is also linked to the acoustic characteristics of vowel sounds. Vowel timbre is…
Seitz notation for symmetry operations of space groups.
Litvin, Daniel B; Kopský, Vojtěch
2011-07-01
Space-group symmetry operations are given a geometric description and a short-hand matrix notation in International Tables for Crystallography, Volume A, Space-Group Symmetry. We give here the space-group symmetry operations subtables with the corresponding Seitz (R∣t) notation for each included symmetry operation.
A Notation for Rapid Specification of Information Visualization
ERIC Educational Resources Information Center
Lee, Sang Yun
2013-01-01
This thesis describes a notation for rapid specification of information visualization, which can be used as a theoretical framework of integrating various types of information visualization, and its applications at a conceptual level. The notation is devised to codify the major characteristics of data/visual structures in conventionally-used…
Design Languages, Notation Systems, and Instructional Technology: A Case Study
ERIC Educational Resources Information Center
Waters, Sandie H.; Gibbons, Andrew S.
2004-01-01
Notational systems, used in mature fields of study, are closely related to design languages. The future of a technological field depends on the ability to communicate ideas and changes with others in the field. Instructional technology is one field that can benefit from a notation system enabling designers to duplicate, execute, and communicate…
Suggested notation conventions for rotational seismology
Evans, J.R.
2009-01-01
We note substantial inconsistency among authors discussing rotational motions observed with inertial seismic sensors (and much more so in the broader topic of rotational phenomena). Working from physics and other precedents, we propose standard terminology and a preferred reference frame for inertial sensors (Fig. 1) that may be consistently used in discussions of both finite and infinitesimal observed rotational and translational motions in seismology and earthquake engineering. The scope of this article is limited to observations because there are significant differences in the analysis of finite and infinitesimal rotations, though such discussions should remain compatible with those presented here where possible. We recommend the general use of the notation conventions presented in this tutorial, and we recommend that any deviations or alternatives be explicitly defined.
Lee, Souk Min; Hwang, Chung-Ju
2015-01-01
This study aimed to compare the frictional force (FR) in self-ligating brackets among different bracket-archwire angles, bracket materials, and archwire types. Passive and active metal self-ligating brackets and active ceramic self-ligating brackets were included as experimental groups, while conventional twin metal brackets served as a control group. All brackets were maxillary premolar brackets with 0.022 inch [in] slots and a -7° torque. The orthodontic wires used included 0.018 round and 0.019 × 0.025 in rectangular stainless steel wires. The FR was measured at 0°, 5°, and 10° angulations as the wire was drawn through the bracket slots after attaching brackets from each group to the universal testing machine. Static and kinetic FRs were also measured. The passive self-ligating brackets generated a lower FR than all the other brackets. Static and kinetic FRs generally increased with an increase in the bracket-archwire angulation, and the rectangular wire caused significantly higher static and kinetic FRs than the round wire (p < 0.001). The metal passive self-ligating brackets exhibited the lowest static FR at the 0° angulation and a lower increase in static and kinetic FRs with an increase in bracket-archwire angulation than the other brackets, while the conventional twin brackets showed a greater increase than all three experimental brackets. The passive self-ligating brackets showed the lowest FR in this study. Self-ligating brackets can generate varying FRs in vitro according to the wire size, surface characteristics, and bracket-archwire angulation.
Tool Releases Optical Elements From Spring Brackets
NASA Technical Reports Server (NTRS)
Gum, J. S.
1984-01-01
Threaded hooks retract bracket arms holding element. Tool uses three hooks with threaded shanks mounted in ring-shaped holder to pull on tabs to release optical element. One person can easily insert or remove optical element (such as prism or lens) from spring holder or bracket with minimal risk of damage.
Hom-Big Brackets: Theory and Applications
NASA Astrophysics Data System (ADS)
Cai, Liqiang; Sheng, Yunhe
2016-02-01
In this paper, we introduce the notion of hom-big brackets, which is a generalization of Kosmann-Schwarzbach's big brackets. We show that it gives rise to a graded hom-Lie algebra. Thus, it is a useful tool to study hom-structures. In particular, we use it to describe hom-Lie bialgebras and hom-Nijenhuis operators.
Morina, Enver; Eliades, Theodore; Pandis, Nikolaos; Jäger, Andreas; Bourauel, Christoph
2008-06-01
The purpose of this research was to investigate the torque capacity of active and passive self-ligating brackets compared with metallic, ceramic, and polycarbonate edgewise brackets. Six types of orthodontic brackets were included in the study: the self-ligating Speed and Damon2, the stainless steel (SS), Ultratrimm and Discovery, the ceramic bracket, Fascination 2, and the polycarbonate bracket, Brillant. All brackets had a 0.022-inch slot size and were torqued with 0.019 x 0.025-inch SS archwires. For this purpose, the labial crown torque of an upper central incisor was measured in a simulated intraoral clinical situation using the orthodontic measurement and simulation system (OMSS). A torque of 20 degrees was applied and the correction of the misalignement was simulated experimentally with the OMSS. Each bracket/wire combination was measured five times. Maximum torquing moments and torque loss were determined. The results were analysed with one-way analysis of variance, with the bracket serving as the sole discriminating variable, and the Tukey test at the 0.05 level of significance. The ceramic bracket (Fascination 2) presented the highest torquing moment (35 Nmm) and, together with a SS bracket, the lowest torque loss (4.6 degrees). Self-ligating, polycarbonate, and selective metallic brackets demonstrated almost a 7-fold decreased moment developed during insertion of a 0.019 x 0.022-inch SS wire into a 0.022-inch slot and a 100 per cent increase in loss.
Arici, S; Regan, D
1997-05-01
The mean tensile/peel bond strengths were evaluated for three types of aesthetic brackets (a ceramic-reinforced bracket and two generations of a ceramic/polycarbonate combination bracket). These were found to be significantly lower than the mean tensile/peel bond strength of a convention foil-mesh stainless steel bracket base. Failure of the ceramic-reinforced polycarbonate brackets occurred predominantly by fracture of the tie wings during testing. With the ceramic/polycarbonate combination brackets, the majority of the specimens failed due to separation of the ceramic and polycarbonate parts of the bracket.
ERIC Educational Resources Information Center
Heiland, Teresa L.
2015-01-01
Four undergraduate dance majors learned Motif Notation and Labanotation using a second-language acquisition, playful, constructivist approach to learning notation literacy in order to learn and dance the "Parsons Etude." Qualitative outcomes were gathered from student journals and pre- and post-tests that assessed for levels of improved…
ERIC Educational Resources Information Center
Heiland, Teresa L.
2015-01-01
Four undergraduate dance majors learned Motif Notation and Labanotation using a second-language acquisition, playful, constructivist approach to learning notation literacy in order to learn and dance the "Parsons Etude." Qualitative outcomes were gathered from student journals and pre- and post-tests that assessed for levels of improved…
Comparative evaluation of ceramic bracket base designs.
Bordeaux, J M; Moore, R N; Bagby, M D
1994-06-01
Since the initial introduction of ceramic brackets, base designs have been modified to reduce tooth damage during debonding. The purpose of this study was to compare shear and tensile bond strengths and fracture sites of four second-generation ceramic brackets: Allure IV (A) (GAC International, Inc., Central Islip, N.Y.), Ceramaflex (C) (TP Orthodontics, Inc., LaPorte, Ind.), Intrigue (I) (Lancer Orthodontics, Carlsbad, Calif.), Transcend 2000 (T) (Unitek Corp., Monrovia, Calif.), and a foil-mesh base stainless steel bracket, DynaBond II (D) (Unitek Corp., Monrovia, Calif.). Twenty brackets of each type were bonded to 100 mandibular bovine incisor teeth with Concise bonding adhesive. The samples were thermocycled for 24 hours and the brackets were debonded with an Instron universal testing machine (Instron Corp., Canton, Mass.). A modified Transcend debonding instrument was used for tensile debonding, whereas a chisel was used for shear debonding. An analysis of variance was performed with a 0.05 level of confidence. Mean shear strengths (kg/cm2) necessary to debond were 174.0 (A), 71.0 (C), 189.0 (I), 228.0 (T), and 160.0 (D). Mean tensile strengths (kg/cm2) were 27.0 (A), 26.7 (C), 51.3 (I), 56.5 (T), and 48.6 (D). Fracture sites examined with a light microscope showed no enamel damage with any of the ceramic brackets. Intrigue was the only bracket to fracture and had 30% bracket fracture in the tensile mode and 20% bracket fracture in the shear mode. The percentage of fractures at the adhesive-bracket base interface for shear and tensile modes, respectively, were 80, 100 (A); 100, 90 (C); 10, 60 (I); 60, 90 (T); and 90, 80 (D).(ABSTRACT TRUNCATED AT 250 WORDS)
Are torque values of preadjusted brackets precise?
STREVA, Alessandra Motta; COTRIM-FERREIRA, Flávio Augusto; GARIB, Daniela Gamba; CARVALHO, Paulo Eduardo Guedes
2011-01-01
Objective The aim of the present study was to verify the torque precision of metallic brackets with MBT prescription using the canine brackets as the representative sample of six commercial brands. Material and Methods Twenty maxillary and 20 mandibular canine brackets of one of the following commercial brands were selected: 3M Unitek, Abzil, American Orthodontics, TP Orthodontics, Morelli and Ortho Organizers. The torque angle, established by reference points and lines, was measured by an operator using an optical microscope coupled to a computer. The values were compared to those established by the MBT prescription. Results The results showed that for the maxillary canine brackets, only the Morelli torque (-3.33º) presented statistically significant difference from the proposed values (-7º). For the mandibular canines, American Orthodontics (-6.34º) and Ortho Organizers (-6.25º) presented statistically significant differences from the standards (-6º). Comparing the brands, Morelli presented statistically significant differences in comparison with all the other brands for maxillary canine brackets. For the mandibular canine brackets, there was no statistically significant difference between the brands. Conclusions There are significant variations in torque values of some of the brackets assessed, which would clinically compromise the buccolingual positioning of the tooth at the end of orthodontic treatment. PMID:21956587
Bond strength of thermally recycled metal brackets.
Wheeler, J J; Ackerman, R J
1983-03-01
Bracket recycling has emerged concurrently with the practice of direct bonding. This study was undertaken to determine the effect of recycling on the retention of mesh-backed stainless steel brackets. Mesh strand diameter was measured on forty new brackets. These brackets were bonded to recently extracted human premolar teeth, and the tensile force required to fracture each bond was recorded. The brackets were then reconditioned by a thermal process. The mesh strand size was remeasured and the tensile test was repeated. It was found that (1) mesh strand diameter decreased 7 percent during the reconditioning process (93.89 microns +/- 3.17 S.D. compared to 87.07 microns +/- 4.76 S.D., z = 17.62, P less than 1 X 10(-5) ), (2) new bracket bonds were 6 percent stronger than recycled bracket bonds (43.88 pounds +/- 7.98 S.D. bond strength), and (3) reduction in mesh strand diameter during the reconditioning process did not correlate with changes in bond strength between initial and recycled bonding (Pearson r = 0.038).
Unification of the matrix notation in molecular surface science
NASA Astrophysics Data System (ADS)
Merz, Leo; Ernst, Karl-Heinz
2010-06-01
The matrix notation connecting the adsorbate lattice with the substrate is a suitable method to define periodic molecular overlayers on single crystalline surfaces. Despite the simplicity of this notation, there are different sets of rules in use, which are incomplete and allow ambiguous results. We suggest here a new consistent set of rules for unit cell selection and how to find in a uniform way a single matrix notation for equivalent structures. This is in particular important for meaningful database entries. Using examples from the literature, we show why existing rules fail to give unambiguous results and discuss in a tutorial manner how to apply the new rules.
Heat Exchanger Support Bracket Design Calculations
Rucinski, Russ; /Fermilab
1995-01-12
This engineering note documents the design of the heat exchanger support brackets. The heat exchanger is roughly 40 feet long, 22 inches in diameter and weighs 6750 pounds. It will be mounted on two identical support brackets that are anchored to a concrete wall. The design calculations were done for one bracket supporting the full weight of the heat exchanger, rounded up to 6800 pounds. The design follows the American Institute of Steel Construction (AISC) Manual of steel construction, Eighth edition. All calculated stresses and loads on welds were below allowables.
Description of ITRF construction using UML notation
NASA Astrophysics Data System (ADS)
Paśnicka, M.; Szafranek, K.; Zwirowicz-Rutkowska, A.
2012-04-01
International Terrestrial Reference Frame (ITRF), as a practical realization of the International Terrestrial Reference System (ITRS), is based on long-term observations of four techniques: Global Navigation Satellite System (GNSS), Satellite Laser Ranging (SLR), DORIS. As a consequence contribution to ITRF of each of the mentioned techniques is different (e.g. origin of ITRF2008 was determined basing on SLR, scale using SLR and VLBI, and orientation was the result of all four techniques). ITRF is updated regularly with the most recent versions being ITRF97, ITRF2000, ITRF2005, ITRF2008. ITRF2008 is based on reprocessed solutions (time series of station positions and Earth Orientation Parameters) of all four techniques. The paper presents procedure of determining ITRF2008 using UML (Unified Modeling Language) - one of the graphical notations commonly used for information modeling. Concepts are represented as classes with their names, attributes, and different kinds of links between them. The main purpose of this paper is a comprehensive description of relationships between basic terms related to ITRF.
Auditory imagery from musical notation in expert musicians.
Brodsky, Warren; Henik, Avishai; Rubinstein, Bat-Sheva; Zorman, Moshe
2003-05-01
Anecdotal evidence has suggested that musical notation can trigger auditory images. Expert musicians silently read scores containing well-known themes embedded into the notation of an embellished phrase and judged if a tune heard aloud thereafter was the original theme (i.e., melodic target) or not (i.e., melodic lure). Three experiments were conducted employing four score-reading conditions: normal nondistracted reading, concurrent rhythmic distraction, phonatory interference, and obstruction by auditory stimuli. The findings demonstrate that phonatory interference impaired recognition of original themes more than did the other conditions. We propose that notational audiation is the silent reading of musical notation resulting in auditory imagery. The research suggests that it also elicits kinesthetic-like phonatory processes.
Safety Case Notations: Alternatives for the Non-Graphically Inclined?
NASA Technical Reports Server (NTRS)
Holloway, C. M.
2008-01-01
This working paper presents preliminary ideas of five possible text-based notations for representing safety cases, which may be easier for non-graphically inclined people to use and understand than the currently popular graphics-based representations.
Gap-minimal systems of notations and the constructible hierarchy
NASA Technical Reports Server (NTRS)
Lucian, M. L.
1972-01-01
If a constructibly countable ordinal alpha is a gap ordinal, then the order type of the set of index ordinals smaller than alpha is exactly alpha. The gap ordinals are the only points of discontinuity of a certain ordinal-valued function. The notion of gap minimality for well ordered systems of notations is defined, and the existence of gap-minimal systems of notations of arbitrarily large constructibly countable length is established.
Comparison of the learning of two notations: A pilot study.
Akram, Ashfaq; Fuadfuad, Maher D; Malik, Arshad Mahmood; Nasir Alzurfi, Balsam Mahdi; Changmai, Manah Chandra; Madlena, Melinda
2017-04-01
MICAP is a new notation in which the teeth are indicated by letters (I-incisor, C-canine, P-premolar, M-molar) and numbers [1,2,3] which are written superscript and subscript on the relevant letters. FDI tooth notation is a two digit system where one digit shows quadrant and the second one shows the tooth of the quadrant. This study aimed to compare the short term retention of knowledge of two notation systems (FDI two digit system and MICAP notation) by lecture method. Undergraduate students [N=80] of three schools participated in a cross-over study. Two theory-driven classroom based lectures on MICAP notation and FDI notation were delivered separately. Data were collected using eight randomly selected permanent teeth to be written in MICAP format and FDI format at pretest (before the lecture), post-test I (immediately after lecture) and post-test II (one week after the lecture). Analysis was done by SPSS version 20.0 using repeated measures ANCOVA and independent t-test. The results of pre-test and post-test I were similar for FDI education. Similar results were found between post-test I and post-test II for MICAP and FDI notations. The study findings indicated that the two notations (FDI and MICAP) were equally mind cognitive. However, the sample size used in this study may not reflect the global scenario. Therefore, we suggest more studies to be performed for prospective adaptation of MICAP in dental curriculum.
Comparison of the learning of two notations: A pilot study
AKRAM, ASHFAQ; FUADFUAD, MAHER D; MALIK, ARSHAD MAHMOOD; NASIR ALZURFI, BALSAM MAHDI; CHANGMAI, MANAH CHANDRA; MADLENA, MELINDA
2017-01-01
Introduction: MICAP is a new notation in which the teeth are indicated by letters (I-incisor, C-canine, P-premolar, M-molar) and numbers [1,2,3] which are written superscript and subscript on the relevant letters. FDI tooth notation is a two digit system where one digit shows quadrant and the second one shows the tooth of the quadrant. This study aimed to compare the short term retention of knowledge of two notation systems (FDI two digit system and MICAP notation) by lecture method. Methods: Undergraduate students [N=80] of three schools participated in a cross-over study. Two theory-driven classroom based lectures on MICAP notation and FDI notation were delivered separately. Data were collected using eight randomly selected permanent teeth to be written in MICAP format and FDI format at pretest (before the lecture), post-test I (immediately after lecture) and post-test II (one week after the lecture). Analysis was done by SPSS version 20.0 using repeated measures ANCOVA and independent t-test. Results: The results of pre-test and post-test I were similar for FDI education. Similar results were found between post-test I and post-test II for MICAP and FDI notations. Conclusion: The study findings indicated that the two notations (FDI and MICAP) were equally mind cognitive. However, the sample size used in this study may not reflect the global scenario. Therefore, we suggest more studies to be performed for prospective adaptation of MICAP in dental curriculum. PMID:28367462
Effect of enamel surface treatment on the bond strength of metallic brackets in rebonding process.
Pakshir, H R; Zarif Najafi, H; Hajipour, S
2012-12-01
Bond failure after rebonding for newly placed brackets can be reduced by appropriate enamel surface treatment. This in vitro study investigated the effect of two enamel surface treatments on the bond strength of metallic brackets in the rebonding process. After debonding the brackets and removing the residual adhesive on the enamel surface of 50 upper premolar teeth, the teeth were divided into two equal groups. In the first group, the enamel surface was etched with phosphoric acid 37 per cent, and in the second group, the teeth were sandblasted prior to acid etching. After bonding of the new brackets, the shear bond strength (SBS), probability of bond failures, and adhesive remnant index (ARI) were determined and compared with the t-test, Weibull analysis, and chi-square test. Mean SBS in both groups did not differ significantly (P = 0.081). Most bond failures occurred with ARI scores of 2 and 3, and the difference between the two groups was statistically significant (P < 0.001). Weibull analysis showed that for a given stress, the probability of failure differed between groups. Enamel surface preparation with sandblasting prior to acid etching did not significantly improve SBS in bracket rebonding and left more residual adhesive remnants on the enamel surface.
[Brackets and friction in orthodontics: experimental study].
Ben Rejeb Jdir, Saloua; Tobji, Samir; Turki, Wiem; Dallel, Ines; Khedher, Nedra; Ben Amor, Adel
2015-09-01
Many authors have been involved in developing brackets in order to improve the quality, stability, speed and efficiency of orthodontic treatment. In order to reduce friction between bracket and archwire, new therapeutic approaches have been devised based on novel technologies. Among these innovative techniques, self-ligating brackets are increasingly popular. SLBs can be classified into several categories according to their mode of action and their materials. We performed an experimental study to compare the friction forces generated during the sliding of orthodontic archwires made from various alloys through conventional and self-ligating brackets. Results show the favorable influence of SLBs, compared to conventional systems using elastomeric or metal ligatures, on the level of friction, particularly when shape-memory Ni-Ti archwires are used. © EDP Sciences, SFODF, 2015.
Deformation of metal brackets: a comparative study.
Flores, D A; Choi, L K; Caruso, J M; Tomlinson, J L; Scott, G E; Jeiroudi, M T
1994-01-01
The purpose of this study was to determine the effect of material and design on the force and stress required to permanently deform metal brackets. Fourteen types of metal brackets were categorized according to raw material composition, slot torque degree, and wing type. Five types of raw materials, three types of slot torque degree, and four types of wing design were tested using an archwire torque test developed by Flores. An analysis of variance (ANOVA) and t-test showed that all three categories had a significant effect on the force and stress needed to permanently deform metal brackets. Of the three, raw material had the greatest effect on the amount of force. Results showed that 17-4PH and 303S had higher yield strengths and regular twin brackets had higher resistance to deformation. Also, as slot torque degree increased, brackets deformed with less force. Result confirmed that brackets requiring the greatest stress to permanently deform were made of steel with the greatest hardness.
The influence of bracket design on frictional losses in the bracket/arch wire system.
Schumacher, H A; Bourauel, C; Drescher, D
1999-01-01
In arch guided tooth movement, the essential role played by bracket configuration with respect to sliding friction has been recognized by the manufacturers, a fact which has had an increasing impact on the design and marketing of new bracket models in recent years. The aim of the present in-vitro study was to investigate the influence of different bracket designs on sliding mechanics. Five differently shaped stainless steel brackets (Discovery: Dentaurum, Damon SL: A-Company, Synergy: Rocky Mountain Orthodontics, Viazis bracket and Omni Arch appliance: GAC) were compared in the 0.022"-slot system. The Orthodontic Measurement and Simulation System (OMSS) was used to quantify the difference between applied force (NiTi coil spring, 1.0 N) and orthodontically effective force and to determine leveling losses occurring during the sliding process in arch guided tooth movement. Simulated canine retraction was performed using continuous arch wires with the dimensions 0.019" x 0.025" (Standard Steel, Unitek) and 0.020" x 0.020" (Ideal Gold, GAC). Comparison of the brackets revealed friction-induced losses ranging from 20 to 70%, with clear-cut advantages resulting from the newly developed bracket types. However, an increased tendency towards leveling losses in terms of distal rotation (maximum 15 degrees) or buccal root torque (maximum 20 degrees) was recorded, especially with those brackets giving the arch wire increased mobility due to their shaping or lack of ligature wire.
Frictional forces and surface topography of a new ceramic bracket.
Tanne, K; Matsubara, S; Hotei, Y; Sakuda, M; Yoshida, M
1994-09-01
The present study was designed to measure the frictional forces between orthodontic wires and a new ceramic bracket and to investigate the differences in the frictional forces with the new and two previously available ceramic brackets. Frictional forces were measured during the sliding of 0.016 x 0.022-inch and 0.017 x 0.022-inch cobalt-chromium alloy wire through three brackets bonded to a simulated tooth. The wires were not ligated into the brackets, so as to eliminate the influences of ligation on the bracket-wire friction. Further, slot surfaces of the three brackets were examined by scanning electron microscope (SEM). The magnitude of frictional forces produced by the new ceramic bracket was significantly less for both the wires than that produced by the two ceramic brackets at 1% level of confidence. The frictional forces with all the brackets exhibited a slight increase as the wire size became larger. The magnitude of frictional forces decreased substantially as the retraction point shifted more cervically. Slot surfaces of the new ceramic bracket were substantially smoother than those surfaces of the two other ceramic brackets. It is shown that refinements of slot surfaces of the ceramic bracket may be effective to reduce friction, although the bracket-wire frictions in this in vitro study were somewhat underestimated because of the lack of ligation of the wire into the bracket.
Skin notation in the context of workplace exposure standards.
Scansetti, G; Piolatto, G; Rubino, G F
1988-01-01
In the establishment of workplace exposure standards, the potential for cutaneous absorption is taken into consideration through the addition of "skin notation" to the relevant substance. In the TLVs Documentation (ACGIH, 1986) dermal lethal dose to 50% (LD50) or human data are the bases for the assignment of "skin notation" to 91 of 168 substances. For the other substances, the "skin" attribution seems to be based on undocumented statements in 24 (14.5%), skin effects in 13 (8%), and analogy in 7 (4%), while in the remaining 33 (20%) any reference is lacking as to the basis for notation of the cutaneous route of entry. Furthermore, since the established "cut-off" value of 2 g/kg is sometimes bypassed when a notation is added or omitted, the use of dermal LD50 is perplexing. Given the relevance of the skin notation for the validation of threshold limit values (TLVs) in the workplace, a full examination and citation of all available scientific data are recommended when establishing the TLV of substances absorbable through the skin.
Skin notation in the context of workplace exposure standards
Scansetti, G.; Piolatto, G.; Rubino, G.F.
1988-01-01
In the establishment of workplace exposure standards, the potential for cutaneous absorption is taken into consideration through the addition of skin notation to the relevant substance. In the TLVs Documentation (ACGIH, 1986) dermal lethal dose to 50% (LD50) or human data are the bases for the assignment of skin notation to 91 of 168 substances. For the other substances, the skin attribution seems to be based on undocumented statements in 24 (14.5%), skin effects in 13 (8%), and analogy in 7 (4%), while in the remaining 33 (20%) any reference is lacking as to the basis for notation of the cutaneous route of entry. Furthermore, since the established cut-off value of 2 g/kg is sometimes bypassed when a notation is added or omitted, the use of dermal LD50 is perplexing. Given the relevance of the skin notation for the validation of threshold limit values (TLVs) in the workplace, a full examination and citation of all available scientific data are recommended when establishing the TLV of substances absorbable through the skin.
Bracketing as a skill in conducting unstructured qualitative interviews.
Sorsa, Minna Anneli; Kiikkala, Irma; Åstedt-Kurki, Päivi
2015-03-01
To provide an overview of bracketing as a skill in unstructured qualitative research interviews. Researchers affect the qualitative research process. Bracketing in descriptive phenomenology entails researchers setting aside their pre-understanding and acting non-judgementally. In interpretative phenomenology, previous knowledge is used intentionally to create new understanding. A literature search of bracketing in phenomenology and qualitative research. This is a methodology paper examining the researchers' impact in creating data in creating data in qualitative research. Self-knowledge, sensitivity and reflexivity of the researcher enable bracketing. Skilled and experienced researchers are needed to use bracketing in unstructured qualitative research interviews. Bracketing adds scientific rigour and validity to any qualitative study.
Generalized nonholonomic mechanics, servomechanisms and related brackets
NASA Astrophysics Data System (ADS)
Cendra, H.; Grillo, S.
2006-02-01
It is well known that nonholonomic systems obeying D'Alembert's principle are described on the Hamiltonian side, after using the Legendre transformation, by the so-called almost-Poisson brackets. In this paper we define the Lagrangian and Hamiltonian sides of a class of generalized nonholonomic systems (GNHS), obeying a generalized version of D'Alembert's principle, such as rubber wheels (like some simplified models of pneumatic tires) and certain servomechanisms (like the controlled inverted pendulum), and show that corresponding equations of motion can also be described in terms of a bracket. We present essentially all possible brackets in terms of which the mentioned equations can be written down, which include the brackets that appear in the literature, and point out those (if any) that are naturally related to each system. In particular, we show there always exists a Leibniz bracket related to a GNHS, and conversely, that every Leibniz system is a GNHS. The control of the inverted pendulum on a cart is studied as an illustrative example.
[Discussion on logarithmic visual acuity chart and five grade notation].
Luo, Wen-bin; Luo, You-rong
2005-01-01
To explore the scientific aspect of logarithmic visual acuity chart and five grade notation, a visual test-type ten times large as the test-type of 4.0 grade was put 0.5 m before the eye, if the eye saw it, then the visual acuity was 2.0 grade (visual angle 1000' = 16.67 degrees). If moving this test-type to 0.05 m before the eye, 1.0 grade (visual angle 10 000' = 166.7 degrees) was obtained. They are more scientific than original records: hand movement for 2.0 grade and light perception for 1.0 grade. These test-type theoretically satisfy the demand of 5 grade notation. Logarithmic visual acuity chart and 5 grade notation is more superior subject created in China.
Guarita, Monique Kruger; Moresca, Alexa Helena Köhler; Losso, Estela Maris; Moro, Alexandre; Moresca, Ricardo Cesar; Correr, Gisele Maria
2015-01-01
The aim of this study was to evaluate the shear bond strength of rebonded ceramic brackets after subjecting the bracket base to different treatments. Seventy-five premolars were selected and randomly distributed into five groups (n=15), according to the type of the bracket surface treatment: I, no treatment, first bonding (control); II, sandblasting with aluminum oxide; III, sandblasting + silane; IV, silica coating + silane; and V, silicatization performed in a laboratory (Rocatec system). The brackets were fixed on an enamel surface with Transbond XT resin without acid etching. The brackets were then removed and their bases were subjected to different treatments. Thereafter, the brackets were fixed again to the enamel surface and the specimens were subjected to shear bond strength (SBS) test. The adhesive remnant index (ARI) was then evaluated for each specimen. Data were subjected to ANOVA and Tukey's tests (α=0.05). A statistically significant difference was observed only between Rocatec and the other groups; the Rocatec group showed the lowest SBS values. The highest SBS values were observed for group 1, without any significant difference from the values for groups II, III and IV. Most groups had a higher percentage of failures at the enamel-resin interface (score 1). It was concluded that the surface treatments of rebonded ceramic brackets were effective, with SBS values similar to that of the control group, except Rocatec group.
Direct light transmittance through ceramic brackets.
Eliades, T; Johnston, W M; Eliades, G
1995-01-01
The objective of this study was to investigate the degree of direct light transmittance (%T) of various types of esthetic brackets and to correlate these values with their structure, morphologic factors, and composition. Eight types of brackets were used in the study; six brackets of each type were tested. An ultraviolet-visible spectroscopic direct transmission analysis was performed at 320 to 700 nm wavelength range. From each spectrum, the %T corresponded to the peak absorbance wavelength of the photoinitiator of the polymerization was recorded (468 nm). Recorded data were analyzed with one-way analysis of variance and Scheffe's test at alpha = 0.05 significance level. In addition, scanning electron microscope (SEM) images were used to reveal the structure and morphologic factors of the brackets tested. Highest %T values (Mean +/- 1 SD) were obtained from a monocrystal type of bracket (Starfire ["A" Company, San Diego, Calif.] 35.02 +/- 1.59%), followed by a polycrystalline (Fascination [Dentaurum, Pforzhein, Germany] 5.70 +/- 1.41%) and a ceramic/polycarbonate base one (Ceramaflex [TP Orthodontics, Inc., La Porte, Ind.] 4.02 +/- 0.96%). Also other brands presented the following data: Allure (GAC, Central Islip, N.Y.) 3.62 +/- 0.5%; Transcend 2000 (Unitek/3M, Monrovia, Calif.) 2.62 +/- 0.5%; Fascination (edgewise) (Dentaurum, Pforzhein, Germany) 1.97 +/- 0.69%; Lumina (Ormco, Glendora, Calif.) 1.57 +/- 0.5%; Signature (RMO, Denver, Colo.) 1.22 +/- 0.5%. The results showed that the structure, morphologic factors, and composition of the brackets tested were found to affect direct light transmission significantly.(ABSTRACT TRUNCATED AT 250 WORDS)
Representing object oriented specifications and designs with extended data flow notations
NASA Technical Reports Server (NTRS)
Buser, Jon Franklin; Ward, Paul T.
1988-01-01
The issue of using extended data flow notations to document object oriented designs and specifications is discussed. Extended data flow notations, for the purposes here, refer to notations that are based on the rules of Yourdon/DeMarco data flow analysis. The extensions include additional notation for representing real-time systems as well as some proposed extensions specific to object oriented development. Some advantages of data flow notations are stated. How data flow diagrams are used to represent software objects are investigated. Some problem areas with regard to using data flow notations for object oriented development are noted. Some initial solutions to these problems are proposed.
Adjustable Bracket For Entry Of Welding Wire
NASA Technical Reports Server (NTRS)
Gilbert, Jeffrey L.; Gutow, David A.
1993-01-01
Wire-entry bracket on welding torch in robotic welding system provides for adjustment of angle of entry of welding wire over range of plus or minus 30 degrees from nominal entry angle. Wire positioned so it does not hide weld joint in view of through-the-torch computer-vision system part of robot-controlling and -monitoring system. Swiveling bracket also used on nonvision torch on which wire-feed-through tube interferes with workpiece. Angle simply changed to one giving sufficient clearance.
Laser debonding of ceramic orthodontic brackets: a theoretical approach
NASA Astrophysics Data System (ADS)
Kearney, Kristine L.; Marangoni, Roy D.; Rickabaugh, Jeff L.
1992-06-01
Ceramic brackets are an esthetic substitute for conventional stainless steel brackets in orthodontic patients. However, ceramic brackets are more brittle and have higher bond strengths which can lead to bracket breakage and enamel damage during debonding. It has been demonstrated that various lasers can facilitate ceramic bracket removal. One mechanism with the laser is through the softening of the bracket adhesive. The high energy density from the laser on the bracket and adhesive can have a resultant deleterious thermal effect on the pulp of the tooth which may lead to pulpal death. A theoretical computer model of bracket, adhesive, enamel and dentin has been generated for predicting heat flow through this system. Heat fluxes at varying intensities and modes have been input into the program and the resultant temperatures at various points or nodes were determined. Further pursuit should lead to optimum parameters for laser debonding which would have minimal effects on the pulp.
Interior view, detail to show typical bracket with gold leaf ...
Interior view, detail to show typical bracket with gold leaf ornament, here the bracket is located the north of the speaker on the second floor - National Park Seminary, Ballroom, Linden Lane, Silver Spring, Montgomery County, MD
21 CFR 872.5470 - Orthodontic plastic bracket.
Code of Federal Regulations, 2011 CFR
2011-04-01
... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Orthodontic plastic bracket. 872.5470 Section 872...) MEDICAL DEVICES DENTAL DEVICES Therapeutic Devices § 872.5470 Orthodontic plastic bracket. (a) Identification. An orthodontic plastic bracket is a plastic device intended to be bonded to a tooth to apply...
21 CFR 872.5470 - Orthodontic plastic bracket.
Code of Federal Regulations, 2010 CFR
2010-04-01
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Orthodontic plastic bracket. 872.5470 Section 872...) MEDICAL DEVICES DENTAL DEVICES Therapeutic Devices § 872.5470 Orthodontic plastic bracket. (a) Identification. An orthodontic plastic bracket is a plastic device intended to be bonded to a tooth to apply...
21 CFR 872.5470 - Orthodontic plastic bracket.
Code of Federal Regulations, 2014 CFR
2014-04-01
... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Orthodontic plastic bracket. 872.5470 Section 872...) MEDICAL DEVICES DENTAL DEVICES Therapeutic Devices § 872.5470 Orthodontic plastic bracket. (a) Identification. An orthodontic plastic bracket is a plastic device intended to be bonded to a tooth to apply...
21 CFR 872.5470 - Orthodontic plastic bracket.
Code of Federal Regulations, 2013 CFR
2013-04-01
... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Orthodontic plastic bracket. 872.5470 Section 872...) MEDICAL DEVICES DENTAL DEVICES Therapeutic Devices § 872.5470 Orthodontic plastic bracket. (a) Identification. An orthodontic plastic bracket is a plastic device intended to be bonded to a tooth to apply...
21 CFR 872.5470 - Orthodontic plastic bracket.
Code of Federal Regulations, 2012 CFR
2012-04-01
... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Orthodontic plastic bracket. 872.5470 Section 872...) MEDICAL DEVICES DENTAL DEVICES Therapeutic Devices § 872.5470 Orthodontic plastic bracket. (a) Identification. An orthodontic plastic bracket is a plastic device intended to be bonded to a tooth to apply...
Covariant brackets for particles and fields
NASA Astrophysics Data System (ADS)
Asorey, M.; Ciaglia, M.; di Cosmo, F.; Ibort, A.
2017-06-01
A geometrical approach to the covariant formulation of the dynamics of relativistic systems is introduced. A realization of Peierls brackets by means of a bivector field over the space of solutions of the Euler-Lagrange equations of a variational principle is presented. The method is illustrated with some relevant examples.
Covariant Jacobi brackets for test particles
NASA Astrophysics Data System (ADS)
Asorey, M.; Ciaglia, F. M.; di Cosmo, F.; Ibort, A.; Marmo, G.
2017-07-01
We show that the space of observables of test particles has a natural Jacobi structure which is manifestly invariant under the action of the Poincaré group. Poisson algebras may be obtained by imposing further requirements. A generalization of Peierls procedure is used to extend this Jacobi bracket to the space of time-like geodesics on Minkowski spacetime.
18 CFR 3a.31 - Classification markings and special notations.
Code of Federal Regulations, 2012 CFR
2012-04-01
... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Classification markings and special notations. 3a.31 Section 3a.31 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY GENERAL RULES NATIONAL SECURITY INFORMATION Classification...
18 CFR 3a.31 - Classification markings and special notations.
Code of Federal Regulations, 2013 CFR
2013-04-01
... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Classification markings and special notations. 3a.31 Section 3a.31 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY GENERAL RULES NATIONAL SECURITY INFORMATION Classification...
18 CFR 3a.31 - Classification markings and special notations.
Code of Federal Regulations, 2010 CFR
2010-04-01
... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Classification markings and special notations. 3a.31 Section 3a.31 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY GENERAL RULES NATIONAL SECURITY INFORMATION Classification...
40 CFR 60.431 - Definitions and notations.
Code of Federal Regulations, 2014 CFR
2014-07-01
... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Definitions and notations. 60.431 Section 60.431 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS..., package inserts, book jackets, market circulars, magazine inserts, and shopping news, Newspapers, magazine...
40 CFR 60.431 - Definitions and notations.
Code of Federal Regulations, 2013 CFR
2013-07-01
... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Definitions and notations. 60.431 Section 60.431 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS..., package inserts, book jackets, market circulars, magazine inserts, and shopping news, Newspapers, magazine...
Semantic Processing in the Production of Numerals across Notations
ERIC Educational Resources Information Center
Herrera, Amparo; Macizo, Pedro
2012-01-01
In the present work, we conducted a series of experiments to explore the processing stages required to name numerals presented in different notations. To this end, we used the semantic blocking paradigm previously used in psycholinguist studies. We found a facilitative effect of the semantic blocked context relative to the mixed context for Arabic…
Guitar Scales in Music Notation and Tablature Diagrams.
ERIC Educational Resources Information Center
Hammer, Petra
This study guide was designed to help high school students learn the basic skills in classical guitar playing, technique, fingerboard knowledge, and musicianship. The introduction describes how to read the music notation that is presented in traditional music form and also in tablature diagrams showing finger positioning in the guitar neck.…
Semantic Processing in the Production of Numerals across Notations
ERIC Educational Resources Information Center
Herrera, Amparo; Macizo, Pedro
2012-01-01
In the present work, we conducted a series of experiments to explore the processing stages required to name numerals presented in different notations. To this end, we used the semantic blocking paradigm previously used in psycholinguist studies. We found a facilitative effect of the semantic blocked context relative to the mixed context for Arabic…
A Multimodal Neural Network Recruited by Expertise with Musical Notation
ERIC Educational Resources Information Center
Wong, Yetta Kwailing; Gauthier, Isabel
2010-01-01
Prior neuroimaging work on visual perceptual expertise has focused on changes in the visual system, ignoring possible effects of acquiring expert visual skills in nonvisual areas. We investigated expertise for reading musical notation, a skill likely to be associated with multimodal abilities. We compared brain activity in music-reading experts…
Unintended consequences of imprecise notation: An example from mechanics
NASA Astrophysics Data System (ADS)
Gangopadhyaya, Asim; Ramsey, Gordon
2013-04-01
We present a conundrum that results from the imprecise use of notation for partial derivatives. Taking an example from mechanics, we show that lack of proper care in representing partial derivatives in the Lagrangian and Hamiltonian formulations paradoxically leads to two different values for the time derivative of the canonical momentum. Similar apparent paradoxes occur in other areas of physics, such as thermodynamics.
The Misuse of the Circle Notation to Represent Aromatic Rings.
ERIC Educational Resources Information Center
Belloli, Robert C.
1983-01-01
Discusses the confusion and erroneous conclusions that can result from the overuse and misuse of the circle notation to represent aromaticity in polycylic aromatic hydrocarbons. Includes nature of the problem, textbook treatment, and a possible compromise method of representation. (Author/JN)
New framework for standardized notation in wastewater treatment modelling.
Corominas, L L; Rieger, L; Takács, I; Ekama, G; Hauduc, H; Vanrolleghem, P A; Oehmen, A; Gernaey, K V; van Loosdrecht, M C M; Comeau, Y
2010-01-01
Many unit process models are available in the field of wastewater treatment. All of these models use their own notation, causing problems for documentation, implementation and connection of different models (using different sets of state variables). The main goal of this paper is to propose a new notational framework which allows unique and systematic naming of state variables and parameters of biokinetic models in the wastewater treatment field. The symbols are based on one main letter that gives a general description of the state variable or parameter and several subscript levels that provide greater specification. Only those levels that make the name unique within the model context are needed in creating the symbol. The paper describes specific problems encountered with the currently used notation, presents the proposed framework and provides additional practical examples. The overall result is a framework that can be used in whole plant modelling, which consists of different fields such as activated sludge, anaerobic digestion, sidestream treatment, membrane bioreactors, metabolic approaches, fate of micropollutants and biofilm processes. The main objective of this consensus building paper is to establish a consistent set of rules that can be applied to existing and most importantly, future models. Applying the proposed notation should make it easier for everyone active in the wastewater treatment field to read, write and review documents describing modelling projects.
Forming an Estudiantina and Symbols of Music Notation.
ERIC Educational Resources Information Center
Horne, Anne
This guide for music teachers in Spanish/English bilingual education is an attempt at gathering the basic musical vocabulary and presenting it in English and Spanish, and is adaptable to all levels. The units cover: forming an estudiantina, including cost ssand method of instruction; symbols of musical notation and definition of musical terms, in…
Articulated Multimedia Physics, Lesson 3, The Arithmetic of Scientific Notation.
ERIC Educational Resources Information Center
New York Inst. of Tech., Old Westbury.
As the third lesson of the Articulated Multimedia Physics Course, instructional materials are presented in this study guide. An introductory description is given for scientific notation methods. The subject content is provided in scrambled form, and the use of matrix transparencies is required for students to control their learning process.…
Effects of Music Notation Reinforcement on Aural Memory for Melodies
ERIC Educational Resources Information Center
Buonviri, Nathan
2015-01-01
The purpose of this study was to investigate effects of music notation reinforcement on aural memory for melodies. Participants were 41 undergraduate and graduate music majors in a within-subjects design. Experimental trials tested melodic memory through a sequence of target melodies, distraction melodies, and matched and unmatched answer choices.…
Effects of Music Notation Reinforcement on Aural Memory for Melodies
ERIC Educational Resources Information Center
Buonviri, Nathan
2015-01-01
The purpose of this study was to investigate effects of music notation reinforcement on aural memory for melodies. Participants were 41 undergraduate and graduate music majors in a within-subjects design. Experimental trials tested melodic memory through a sequence of target melodies, distraction melodies, and matched and unmatched answer choices.…
Preserving Musicality through Pictures: A Linguistic Pathway to Conventional Notation
ERIC Educational Resources Information Center
Nordquist, Alice L.
2016-01-01
The natural musicality so often present in children's singing can begin to fade as the focus of a lesson shifts to the process of reading and writing conventional notation symbols. Approaching the study of music from a linguistic perspective preserves the pace and flow that is inherent in spoken language and song. SongWorks teaching practices…
Developing Systems of Notation as a Trace of Reasoning
ERIC Educational Resources Information Center
Tillema, Erik; Hackenberg, Amy
2011-01-01
In this paper, we engage in a thought experiment about how students might notate their reasoning for composing fractions multiplicatively (taking a fraction of a fraction and determining its size in relation to the whole). In the thought experiment we differentiate between two levels of a fraction composition scheme, which have been identified in…
A Multimodal Neural Network Recruited by Expertise with Musical Notation
ERIC Educational Resources Information Center
Wong, Yetta Kwailing; Gauthier, Isabel
2010-01-01
Prior neuroimaging work on visual perceptual expertise has focused on changes in the visual system, ignoring possible effects of acquiring expert visual skills in nonvisual areas. We investigated expertise for reading musical notation, a skill likely to be associated with multimodal abilities. We compared brain activity in music-reading experts…
Preserving Musicality through Pictures: A Linguistic Pathway to Conventional Notation
ERIC Educational Resources Information Center
Nordquist, Alice L.
2016-01-01
The natural musicality so often present in children's singing can begin to fade as the focus of a lesson shifts to the process of reading and writing conventional notation symbols. Approaching the study of music from a linguistic perspective preserves the pace and flow that is inherent in spoken language and song. SongWorks teaching practices…
The Misuse of the Circle Notation to Represent Aromatic Rings.
ERIC Educational Resources Information Center
Belloli, Robert C.
1983-01-01
Discusses the confusion and erroneous conclusions that can result from the overuse and misuse of the circle notation to represent aromaticity in polycylic aromatic hydrocarbons. Includes nature of the problem, textbook treatment, and a possible compromise method of representation. (Author/JN)
Shear Bond Strength of Bracket Bases to Adhesives Based on Bracket Base Design
2016-04-13
accepted technique since introduced by Newman in 1965. Bond strength values ranging from 6-8 MPa for composite resin cements were originally reported...bonding orthodontic brackets. Our in vitro study utilized a cured block of Transbond XT TM composite resin with minimal filler particles. This in...the specimen surface area. The Adhesive Remnant Index (ARI) was used to assess the amount of resin left on the bracket base after debonding. A
Assessment of dimensional accuracy of preadjusted metal injection molding orthodontic brackets
Alavi, Shiva; Tajmirriahi, Farnaz
2016-01-01
Background: the aim of this study is to evaluate the dimensional accuracy of McLaughlin, Bennett, and Trevisi (MBT) brackets manufactured by two different companies (American Orthodontics and Ortho Organizers) and determine variations in incorporation of values in relation to tip and torque in these products. Materials and Methods: In the present analytical/descriptive study, 64 maxillary right central brackets manufactured by two companies (American Orthodontics and Ortho Organizers) were selected randomly and evaluated for the accuracy of the values in relation to torque and angulation presented by the manufacturers. They were placed in a video measuring machine using special revolvers under them and were positioned in a manner so that the light beams would be directed on the floor of the slot without the slot walls being seen. Then, the software program of the same machine was used to determine the values of each bracket type. The means of measurements were determined for each sample and were analyzed with independent t-test and one-sample t-test. Results: Based on the confidence interval, it can be concluded that at 95% probability, the means of tip angles of maxillary right central brackets of these two brands were 4.1–4.3° and the torque angles were 16.39–16.72°. The tips in these samples were at a range of 3.33–4.98°, and the torque was at a range of 15.22–18.48°. Conclusion: In the present study, there were no significant differences in the angulation incorporated into the brackets from the two companies; however, they were significantly different from the tiP values for the MBT prescription. In relation to torque, there was a significant difference between the American Orthodontic brackets exhibited significant differences with the reported 17°, too. PMID:27857770
Ireland, Anthony J; Sherriff, Martyn
2006-02-01
The two objectives of this experiment were to determine the surface temperature of enamel following acid etching, rinsing and drying, and to see whether two commercially available orthodontic brackets could be bonded to enamel using an anaerobic adhesive. Enamel surface temperature was determined in vivo using a surface temperature probe on a total of 60 patients. Stainless steel orthodontic brackets were bonded to human enamel using an anaerobic adhesive and a control orthodontic adhesive. The enamel was etched prior to bonding either with a solution of 37% o-phosphoric acid or, in the case of the anaerobic adhesive specimens, with a solution of 37% o-phosphoric acid containing copper (II) chloride. After bench curing the specimens were shear bond tested to failure and the load at debond recorded in each case. The bond test results were analyzed using median force to debond (N) and 95% confidence intervals, Kaplan-Meier survival probabilities and log-rank tests. After etching rinsing and drying the enamel surface temperature ranged from 21.54 to 24.19 degrees C, which is within the range suitable for anaerobic adhesive use. Bond testing to failure demonstrated that bracket base design affected the measured force to debond with both the anaerobic adhesive under test and the control adhesive. In addition, the anaerobic adhesive was affected by the material composition of the bracket base and curing time. After 1h of curing and using the Miniature Twin bracket, the measured force to debond exceeded the 10 min force to debond results of the control adhesive. It is possible to bond commercially available orthodontic brackets to teeth using an anaerobic adhesive.
Effect of Color-Coded Notation on Music Achievement of Elementary Instrumental Students.
ERIC Educational Resources Information Center
Rogers, George L.
1991-01-01
Presents results of a study of color-coded notation to teach music reading to instrumental students. Finds no clear evidence that color-coded notation enhances achievement on performing by memory, sight-reading, or note naming. Suggests that some students depended on the color-coding and were unable to read uncolored notation well. (DK)
Ceramic bracket design: an analysis using the finite element method.
Ghosh, J; Nanda, R S; Duncanson, M G; Currier, G F
1995-12-01
This investigation was designed to generate finite element models for selected ceramic brackets and graphically display the stress distribution in the brackets when subjected to arch wire torsion and tipping forces. Six commercially available ceramic brackets, one monocrystalline and five polycrystalline alumina, of twin bracket design for the permanent maxillary left central incisor were studied. Three-dimensional computer models of the brackets were constructed and loading forces, similar to those applied by a full-size (0.0215 x 0.028 inch) stainless steel arch wire in torsion and tipping necessary to fracture ceramic brackets, were applied to the models. Stress levels were recorded at relevant points common among the various brackets. High stress levels were observed at areas of abrupt change in geometry and shape. The design of the wire slot and wings for the Contour bracket (Class One Orthodontic Products, Lubbock, Texas) and of the outer edges of the wire slot for the Allure bracket (GAC, Central Islip, N.Y.) were found to be good in terms of even stress distribution. The brackets with an isthmus connecting the wings seemed to resist stresses better than the one bracket that did not have this feature. The design of the isthmus for the Transcend (Unitek/3M, Monrovia, Calif.) and Lumina (Ormco, Glendora, Calif.) brackets were found to be acceptable as well. The Starfire bracket ("A" Company, San Diego, Calif.) showed high stresses and irregular stress distribution, because it had sharp angles, no rounded corners, and no isthmus. The finite element method proved to be a useful tool in the stress analysis of ceramic orthodontic brackets subjected to various forces.(ABSTRACT TRUNCATED AT 250 WORDS)
Conceptual design for PSP mounting bracket
Ransom, G.; Stein, R.
1991-12-31
Protective structural packages (PSP`s or overpacks) used to ship 2 1/2-ton UF{sub 6} product cylinders are bolted to truck trailers. All bolts penetrate two longitudinal rows of wooden planks. Removal and replacement is required at various intervals for maintenance and routine testing. A conceptual design is presented for mounting brackets which would securely attach PSP`s to trailer frames, reduce removal and replacement time, and minimize risk of personnel injury.
First Integrals, Liouville Theorem, and Dirac Brackets
NASA Astrophysics Data System (ADS)
Gleria, Iram; Filho, Tarcísio M. Rocha; Figueiredo Neto, Annibal D.; Vianna, José David M.
2017-08-01
In this paper, we discuss the conditions for the existence of first integrals of movement and the Liouville theorem on integrable systems. We revise the core results of the Hamilton-Jacobi theory and discuss the extension of the formalism to encompass constrained systems using Dirac brackets, originally developed in the context of the canonical quantization of constrained systems. As an application, we analyze a Hamiltonian that represents the classical limit of a Fermionic system of oscillators.
The effect of adhesive type and thickness on bond strength of orthodontic brackets.
Mackay, F
1992-02-01
Fine-mesh based brackets were bonded to plastic cylinders using four different adhesives. Adhesive thickness was controlled using a bonding jig. The bond was then tested to failure using a shear force. Each adhesive had its own minimum thickness, probably related to its viscosity. Increasing the thickness of the adhesiveness to 0.26 mm, using a stainless steel spacer had minimal effect on their mean shear bond strength.
The Astronomy Workshop: Scientific Notation and Solar System Visualizer
NASA Astrophysics Data System (ADS)
Deming, Grace; Hamilton, D.; Hayes-Gehrke, M.
2008-09-01
The Astronomy Workshop (http://janus.astro.umd.edu) is a collection of interactive World Wide Web tools that were developed under the direction of Doug Hamilton for use in undergraduate classes and by the general public. The philosophy of the site is to foster student interest in astronomy by exploiting their fascination with computers and the internet. We have expanded the "Scientific Notation” tool from simply converting decimal numbers into and out of scientific notation to adding, subtracting, multiplying, and dividing numbers expressed in scientific notation. Students practice these skills and when confident they may complete a quiz. In addition, there are suggestions on how instructors may use the site to encourage students to practice these basic skills. The Solar System Visualizer animates orbits of planets, moons, and rings to scale. Extrasolar planetary systems are also featured. This research was sponsored by NASA EPO grant NNG06GGF99G.
Toothpaste Prevents Debonded Brackets on Erosive Enamel
Barros, Érico Luiz Damasceno; Pinto, Shelon Cristina Souza; Borges, Alvaro Henrique; Tonetto, Mateus Rodrigues; Ellwood, Roger Phillip; Pretty, Ian; Bandéca, Matheus Coelho
2015-01-01
This study evaluated the effect of high fluoride dentifrice on the bond strength of brackets after erosive challenge. Eighty-four enamel specimens were divided into seven groups (n = 12): WN (distilled water/no acid challenge), W3C (distilled water/3 cycles of acid challenge), and W6C (distilled water/6 cycles of acid challenge) were not submitted to dentifrice treatment. Groups RF3C (regular fluoride dentifrice/3 cycles of acid challenge) and RF6C (regular fluoride dentifrice/6 cycles of acid challenge) were treated with dentifrices containing 1450 μg F−/g and HF3C (high fluoride dentifrice/3 cycles of acid challenge) and HF6C (high fluoride dentifrice/6 cycles of acid challenge) were with 5000 μg F−/g. Acid challenges were performed for seven days. After bond strength test, there was no significant difference among groups submitted to 3 cycles of acid challenge (P > 0.05). Statistically significant difference was found between the regular and high fluoride dentifrices after 6 cycles of acid challenge (<0.05). Similar areas of adhesive remaining were found among control groups and among groups W6C, RF3C, RF6C, HF3C, and HF6C. The high fluoride dentifrice was able to prevent the reduction of bond strength values of brackets submitted to acid challenge. Clinical relevance: the high fluoride toothpaste prevents debonded brackets on erosive enamel. PMID:25879058
Colour and translucency of tooth-coloured orthodontic brackets.
Lee, Yong-Keun
2008-04-01
The objective of this study was to determine the reflected and transmitted colours and the diffuse light transmittance of tooth-coloured brackets. Four ceramic and four plastic brands were evaluated and five brackets of each brand were tested. Reflected colour and spectral reflectance of the labial surface of the brackets were measured according to the Commission Internationale de l'Eclairage (CIE) colour scale and transmitted colour and diffuse spectral transmittance measured with a spectrophotometer. One-way analyses of variance were performed for the reflected and transmitted colour co-ordinates (CIE L*, a*, and b*) and for light transmittance according to bracket brand. The range for CIE L* (lightness) was 36.2-50.3, for a* (red-green parameter) -1.3-3.8 and for b* (yellow-blue parameter) -2.9-11.2. All these colour co-ordinates were influenced by bracket brand (P < 0.05). Diffuse light transmittance was also influenced by bracket brand and ranged from 44.9 to 75.9 per cent (P < 0.05). Colour and transmittance varied by bracket brand. Variations in optical properties influenced the aesthetic performance of the brackets and the degree of cure of the adhesive that is possible through the brackets. Further studies on the clinical implications of colour matching of tooth-coloured brackets with teeth should now be performed.
A Formal Messaging Notation for Alaskan Aviation Data
NASA Technical Reports Server (NTRS)
Rios, Joseph L.
2015-01-01
Data exchange is an increasingly important aspect of the National Airspace System. While many data communication channels have become more capable of sending and receiving data at higher throughput rates, there is still a need to use communication channels efficiently with limited throughput. The limitation can be based on technological issues, financial considerations, or both. This paper provides a complete description of several important aviation weather data in Abstract Syntax Notation format. By doing so, data providers can take advantage of Abstract Syntax Notation's ability to encode data in a highly compressed format. When data such as pilot weather reports, surface weather observations, and various weather predictions are compressed in such a manner, it allows for the efficient use of throughput-limited communication channels. This paper provides details on the Abstract Syntax Notation One (ASN.1) implementation for Alaskan aviation data, and demonstrates its use on real-world aviation weather data samples as Alaska has sparse terrestrial data infrastructure and data are often sent via relatively costly satellite channels.
Efficient Hessian computation using sparse matrix derivatives in RAM notation.
von Oertzen, Timo; Brick, Timothy R
2014-06-01
This article proposes a new, more efficient method to compute the minus two log likelihood, its gradient, and the Hessian for structural equation models (SEMs) in reticular action model (RAM) notation. The method exploits the beneficial aspect of RAM notation that the matrix derivatives used in RAM are sparse. For an SEM with K variables, P parameters, and P' entries in the symmetrical or asymmetrical matrix of the RAM notation filled with parameters, the asymptotical run time of the algorithm is O(P ' K (2) + P (2) K (2) + K (3)). The naive implementation and numerical implementations are both O(P (2) K (3)), so that for typical applications of SEM, the proposed algorithm is asymptotically K times faster than the best previously known algorithm. A simulation comparison with a numerical algorithm shows that the asymptotical efficiency is transferred to an applied computational advantage that is crucial for the application of maximum likelihood estimation, even in small, but especially in moderate or large, SEMs.
Frictional forces related to self-ligating brackets.
Pizzoni, L; Ravnholt, G; Melsen, B
1998-06-01
Orthodontic tooth movement can be regarded as teeth sliding on a wire like pearls on a string, the force being supplied by springs or elastics. The movement implies friction between wire and bracket, taking up part of the force and leaving an uncontrolled amount to act on the teeth. The friction is likely to depend on bracket construction and wire material. Therefore, in this investigation the friction of self-ligating brackets and beta-titanium wires was evaluated, as opposed to more conventional configurations. Carried by low-friction linear ball bearings, a bracket was made to slide along an out-stretched archwire with minimal (and known) basic friction, either parallel or at an angle to the wire. Two self-ligating brackets were used in their closed position without any normal force. Friction was tested against four wires: stainless steel and beta-titanium, both in round and rectangular cross-sections. The force used to overcome friction and to move the bracket was measured on a testing machine at 10 mm/min, and the basic friction was subtracted. The results show that round wires had a lower friction than rectangular wires, the beta-titanium wires had a markedly higher friction than stainless steel wires, and friction increased with angulation for all bracket/wire combinations. The self-ligating brackets had a markedly lower friction than conventional brackets at all angulations, and self-ligating brackets, closed by the capping of a conventional design, exhibited a significantly lower friction than self-ligating brackets closed by a spring. The selection of bracket design, wire material, and wire cross-section significantly influences the forces acting in a continuous arch system.
Peierls brackets in non-Lagrangian field theory
NASA Astrophysics Data System (ADS)
Sharapov, A. A.
2014-10-01
The concept of Lagrange structure allows one to systematically quantize the Lagrangian and non-Lagrangian dynamics within the path-integral approach. In this paper, I show that any Lagrange structure gives rise to a covariant Poisson bracket on the space of solutions to the classical equations of motion, be they Lagrangian or not. The bracket generalize the well-known Peierls' bracket construction and make a bridge between the path-integral and the deformation quantization of non-Lagrangian dynamics.
Shear Bond Strength of Orthodontic Brackets Bonded to Zirconium Crowns
Mehmeti, Blerim; Azizi, Bleron; Kelmendi, Jeta; Iljazi-Shahiqi, Donika; Alar, Željko
2017-01-01
Background An increasing demand for esthetic restorations has resulted in an increased use of all-ceramic restorations, such as zirconium. However, one of the challenges the orthodontist must be willing to face is how to increase bond strength between the brackets and various ceramic restorations.Bond strength can beaffected bybracket type, by the material that bracketsaremade of, and their base surface design or retention mode. Aim: of this study was to perform a comparative analysis of the shear bond strength (SBS) of metallic and ceramic orthodontic brackets bonded to all-zirconium ceramic surfaces used for prosthetic restorations, and also to evaluate the fracture mode of these two types of orthodontic brackets. Material and methods Twenty samples/semi-crowns of all-zirconium ceramic, on which orthodontic brackets were bonded, 10 metallic and 10 ceramic polycrystalline brackets, were prepared for this research. SBS has been testedby Universal Testing Machine, with a load applied using a knife edged rod moving at a fixed rate of 1 mm/min, until failure occurred. The force required to debond the brackets was recorded in Newton, then SBS was calculated to MPa. In addition, the samples were analyzed using a digital camera magnifier to determine Adhesive Remnant Index (ARI). Statistical data were processed using t-test, and the level of significance was set at α = 0.05. Results Higher shear bond strength values were observed in metallic brackets bonded to zirconium crowns compared tothoseof ceramic brackets, with a significant difference. During the test, two of the ceramic brackets were partially or totally damaged. Conclusion Metallic brackets, compared to ceramic polycrystalline brackets, seemed tocreate stronger adhesion with all-zirconium surfaces due to their better retention mode. Also, ceramic brackets showed higher fragility during debonding. PMID:28827846
Shear bond strength of new and recycled brackets to enamel.
Tavares, Stenyo Wanderley; Consani, Simonides; Nouer, Darcy Flávio; Magnani, Maria Beatriz Borges de Araújo; Nouer, Paulo Roberto Aranha; Martins, Laura Moura
2006-01-01
The purpose of this study was to evaluate in vitro the shear bond strength of recycled orthodontic brackets. S2C-03Z brackets (Dental Morelli, Brazil) were bonded to the buccal surfaces of 50 extracted human premolars using Concise Orthodontic chemically cured composite resin (3M, USA). The teeth were randomly assigned to 5 groups (n=10), as follows. In group I (control), the bonded brackets remained attached until shear testing (i.e., no debonding/rebonding). In groups II, III and IV, the bonded brackets were detached and rebonded after recycling by 90-microm particle aluminum oxide blasting, silicon carbide stone grinding or an industrial process at a specialized contractor company (Abzil-Lancer, Brazil), respectively. In group V, the bonded brackets were removed and new brackets were bonded to the enamel surface. Shear bond strength was tested in an Instron machine at a crosshead speed of 0.5 mm/min. Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. There was no statistically significant difference (p>0.05) between the control brackets (0.52 kgf/mm2), brackets recycled by aluminum oxide blasting (0.34 kgf/mm2) and new brackets attached to previously bonded teeth (0.43 kgf/mm2). Brackets recycled by the specialized company (0.28 kgf/mm2) and those recycled by silicon carbide stone grinding (0.14 kgf/mm2) showed the lowest shear strength means and differed statistically from control brackets (0.52 kgf/mm2) (p<0.05). In conclusion, the outcomes of this study showed that bracket recycling using 90-microm aluminum oxide particle air-abrasion was efficient and technically simple, and might provide cost reduction for orthodontists and patients alike.
Optimization of a procedure for rebonding dislodged orthodontic brackets.
Mui, B; Rossouw, P E; Kulkarni, G V
1999-06-01
The purpose of this study was to compare shear bond strength (SBS) of bonded and rebonded orthodontic brackets following a variety of commonly used conditioning treatments and using both light-cured and self-cured composite resin systems. Brackets debonded during the initial determination of SBS were rebonded after the removal of residual resin from enamel surfaces using five different treatments: (1) Remove residual resin using a tungsten carbide bur, re-etch enamel surface, then bond a new bracket; (2) Remove resin from the base mesh with micro-etching then rebond the same bracket, (3) Remove residual resin from the enamel surface using resin-removing pliers, recondition the enamel with an air-powder polisher, then bond a new bracket; (4) Remove residual resin using a rubber cup and pumice, then bond a new bracket; (5) Remove residual resin using pliers alone, then bond a new bracket. The results revealed that the light-cured system produced higher shear bond strength in the initial bond than the self-cured system (p<0.005). Reconditioning the enamel surfaces using a tungsten carbide bur and acid-etching gave the highest SBS (difference 5.8 MPa; p<0.01) and clinically favorable fracture characteristics. The data suggest that the optimal procedure for rebonding dislodged orthodontic brackets is to resurface the enamel using a tungsten carbide bur, acid-etch the enamel, and use a new or re-use an old bracket after microetching.
Laser-Aided Ceramic Bracket Debonding: A Comprehensive Review
Ghazanfari, Rezvaneh; Nokhbatolfoghahaei, Hanieh; Alikhasi, Marzieh
2016-01-01
Different techniques have been introduced for the removal of ceramic brackets. Since the early 1990s, lasers have been used experimentally for debonding ceramic brackets. The goal of this study is to give a comprehensive literature review on laser-aided ceramic bracket debonding. PubMed and Google Scholar databases were used to identify dental articles with the following combination of key words: Ceramic brackets, Debonding, and Laser. Sixteen English articles from 2004 to 2015 were selected. The selected studies were categorized according to the variables investigated including the intrapulpal temperature, shear bond strength, debonding time, enamel damage and bracket failure. Most articles reported decreased shear bond strength and debonding time following laser irradiation without any critical and irritating increase in pulpal temperature. There were no reports of bracket failure or enamel damage. Laser irradiation is an efficient way to reduce shear bond strength of ceramic bracket and debonding time. This technique is a safe way for removing ceramic bracket with minimal impact on intrapulpal temperature and enamel surface and it reduces ceramic bracket failure. PMID:27330690
Jayachandran, Balajee; Padmanabhan, Ratna; Vijayalakshmi, Devaki; Padmanabhan, Janardhanam
2016-01-01
Aims and Objectives: This clinical study was conducted to compare the interactive self-ligating twin brackets and the standard double width brackets for their efficiency in Rate of Retraction. Materials and Methods: A total of 20 patients with Angle's class I or class II or class III dento-alveolar malocclusions between the age group of 18-25 years were selected. 10 patients in each group both males and females were randomly selected for the study. Ten patients were bonded using conventional brackets (Group I) the other ten patients were bonded using Interactive self-ligating brackets (Group II). The Rate of retraction was quantified using the scanned models. Pretreatment and post treatment models were taken and scanned to measure the amount of Incisor movement and Anchor loss. Results: (1) Interactive Self-ligating brackets showed significant Rate of retraction when compared with conventional brackets on right and left quadrant. (Group I 0.545 ± .205: Group II 0.827 ± .208 P = .013*) (Group I 0.598 ± .160: Group II 0.804 ± .268 P = .071) (2) Interactive self-ligating brackets when compared with conventional brackets had significant amount of incisor movement on right and left quadrant. (Group I 3.51 ± .548: Group II 4.38 ± .1.06 P = .047*) and (Group I 3.66 ± .899: Group II 4.67 ± 1.02 P = .047*) (3) Conventional brackets showed significant Amount of Anchor loss when compared with that of Interactive self-ligating brackets on right and left quadrant. (Group I .948 ± .392: Group II 0.501 ± .229 P = .013*). In the left side (Group I 0.861 ± .464: Group II 0.498 ± .227 P = .060). Conclusion: The interactive self-ligating brackets show more efficiency in Rate of Retraction, Amount of Incisor movement and Amount of Anchor loss when compared with the conventional brackets. PMID:27307660
Ceramic bracket debonding with ytterbium fiber laser.
Sarp, Ayşe Sena Kabaş; Gülsoy, Murat
2011-09-01
Since the early 1990 s, lasers have been used experimentally for debonding ceramic brackets. Lasers reduce the required debonding force and risk of enamel damage. However, the thermal effect during the laser radiation on dental tissues can cause undesirable results. The aim of this study is to develop a laser debonding technique for ceramic brackets that is better than mechanical debonding and also to minimize the side-effects of laser applications. A new fiber laser (1,070-nm ytterbium fiber laser) was tested, debonding procedure was quantified with a universal testing machine, and intrapulpal temperature was monitored for limiting the injury or pain. Experiments were performed in two sections according to the type of lasing mode: continuous wave (CW) and modulated mode. In continuous wave (CW) mode, a laser was applied on samples with different constant power levels continuously. In the second set of experiments, brackets were irradiated in modulated mode, in which the laser energy was delivered with on-and-off cycles. Laser power and duty cycles were adjusted by controlling the current, which was set to 4.99 A of current for 18 W of emission. Debonding force, debonding time, and work done by a universal testing machine were all significantly decreased for both modalities of laser irradiation compared to the control group. When laser parameters were set to proper doses, a 50% of reduction in required load for debonding and a three-fold decrease in debonding time were observed. Intrapulpal temperature changes were below the accepted threshold value (5.5°C) until the level of 3.5 W of laser power in continuous wave mode. During debonding, the work done by the universal testing machine is decreased up to five times by irradiation. Parameters were compared for both modes of operations and it was concluded that modulated mode laser application (Group 300/900) provided faster and easier debonding with less temperature change.
Causal Poisson bracket via deformation quantization
NASA Astrophysics Data System (ADS)
Berra-Montiel, Jasel; Molgado, Alberto; Palacios-García, César D.
2016-06-01
Starting with the well-defined product of quantum fields at two spacetime points, we explore an associated Poisson structure for classical field theories within the deformation quantization formalism. We realize that the induced star-product is naturally related to the standard Moyal product through an appropriate causal Green’s functions connecting points in the space of classical solutions to the equations of motion. Our results resemble the Peierls-DeWitt bracket that has been analyzed in the multisymplectic context. Once our star-product is defined, we are able to apply the Wigner-Weyl map in order to introduce a generalized version of Wick’s theorem. Finally, we include some examples to explicitly test our method: the real scalar field, the bosonic string and a physically motivated nonlinear particle model. For the field theoretic models, we have encountered causal generalizations of the creation/annihilation relations, and also a causal generalization of the Virasoro algebra for the bosonic string. For the nonlinear particle case, we use the approximate solution in terms of the Green’s function, in order to construct a well-behaved causal bracket.
Ozcan, M; Finnema, K; Ybema, A
2008-04-01
The objectives of this study were to evaluate the effect of silanization on the failure type and shear-peel bond strength (SBS) of ceramic and polycarbonate brackets, and to determine the type of failure when debonded with either a universal testing machine or orthodontic pliers. Silanized and non-silanized ceramic and polycarbonate brackets (N = 48, n = 24 per bracket type) were bonded to extracted caries-free human maxillary central incisors using an alignment apparatus under a weight of 750 g. All bonded specimens were thermocycled 1000 times (5-55 degrees C). Half of the specimens from each group were debonded with a universal testing machine (1 mm/minute) to determine the SBS and the other half by an operator using orthodontic debonding pliers. Failure types of the enamel surface and the bracket base were identified both from visual inspection and digital photographs using the adhesive remnant index (ARI) and base remnant index (BRI). As-received ceramic brackets showed significantly higher bond strength values (11.5 +/- 4.1 MPa) than polycarbonate brackets [6.3 +/- 2.7 MPa; (P = 0.0077; analysis of variance (ANOVA)]. Interaction between bracket types and silanization was not significant (P = 0.4408). Silanization did not significantly improve the mean SBS results either for the ceramic or polycarbonate brackets (12.9 +/- 3.7 and 6.3 +/- 2.7 MPa, respectively; P = 0.4044; two-way ANOVA, Tukey-Kramer adjustment). There was a significant difference between groups in ARI scores for ceramic (P = 0.0991) but not polycarbonate (P = 0.3916; Kruskall-Wallis) brackets. BRI values did not vary significantly for ceramic (P = 0.1476) or polycarbonate (P = 0.0227) brackets. Failure type was not significantly different when brackets were debonded with a universal testing machine or with orthodontic debonding pliers. No enamel damage was observed in any of the groups.
The use and understanding of dental notation systems in UK and Irish dental hospitals.
Pemberton, M N; Ashley, M
2017-10-01
Aim To identify the types of dental notation systems used in dental hospitals, and their perceived advantages and disadvantages. In addition, to record the dental notation used in patient referral letters.Method A self-completed questionnaire survey asking about the use of dental notation systems was distributed to 16 dental hospitals in the UK and Ireland in the summer of 2016. In addition, dentist referrals to the Restorative Dentistry department of the University Dental Hospital of Manchester were sequentially assessed for the dental notation used.Results Twelve hospitals replied. In order of frequency, the notation systems in use were the Alphanumeric, the Palmer, and the Federation Dentaire Internationale system. No hospital used the Universal system. Perceived advantages and disadvantages of each of the different systems were volunteered. One hundred and twenty-four referral letters were assessed and 100 were identified where dental notation was used. The majority used Alphanumeric notation.Conclusion A variety of dental notation systems remain in use in dental hospitals. The move to electronic recording and communication of information regarding teeth is encouraging the use of the Alphanumeric system. General dental practitioners are predominantly using the Alphanumeric system as their notation of choice in referral letters to the Restorative Dentistry department in Manchester.
Comparative Analysis of Bracket Slot Dimensions Evaluating Different Manufacturing Techniques
2015-04-24
Dimensions Evaluating Different Manufacturing Techniques JS. A. DeMeo APPROVED: fk_ 4 ’__/ . .S, M.S., Supervising Professor ,....-------__ ’ - ~l!i...manuscript entitled : "Comparative Analysis of Bracket Slot Dimensions Evaluating Different Manufactur ing Techniques" is appropriately acknowledged and...Harm s Way TITLE Comparative Analysis of Bracket Slot Dimensions Evaluating Different Manufacturing Techniques A THESIS Presented to the
RSRM nozzle actuator bracket/lug fracture mechanics qualification test
NASA Technical Reports Server (NTRS)
Kelley, Peggy
1993-01-01
This is the final report for the actuator bracket/lug fracture mechanics qualification test. The test plan (CTP-0071) outlined a two-phase test program designed to answer questions about the fracture criticality of the redesigned solid rocket motor (RSRM) nozzle actuator bracket. An analysis conducted using the NASA/FLAGRO fracture mechanics computer program indicated that the actuator bracket might be a fracture critical component. In the NASA/FLAGRO analysis, a simple lug model was used to represent the actuator bracket. It was calculated that the bracket would fracture if subjected to an actuator stall load in the presence of a 0.10 in. corner crack at the actuator attachment hole. The 0.10 in. crack size corresponds to the nondestructive inspection detectability limit for the actuator bracket. The inspection method used is the dye penetrant method. The actuator stall load (103,424 lb) is the maximum load which the actuator bracket is required to withstand during motor operation. This testing was designed to establish the accuracy of the analytical model and to directly determine whether the actuator bracket is capable of meeting fracture mechanics safe-life requirements.
Using argument notation to engineer biological simulations with increased confidence
Alden, Kieran; Andrews, Paul S.; Polack, Fiona A. C.; Veiga-Fernandes, Henrique; Coles, Mark C.; Timmis, Jon
2015-01-01
The application of computational and mathematical modelling to explore the mechanics of biological systems is becoming prevalent. To significantly impact biological research, notably in developing novel therapeutics, it is critical that the model adequately represents the captured system. Confidence in adopting in silico approaches can be improved by applying a structured argumentation approach, alongside model development and results analysis. We propose an approach based on argumentation from safety-critical systems engineering, where a system is subjected to a stringent analysis of compliance against identified criteria. We show its use in examining the biological information upon which a model is based, identifying model strengths, highlighting areas requiring additional biological experimentation and providing documentation to support model publication. We demonstrate our use of structured argumentation in the development of a model of lymphoid tissue formation, specifically Peyer's Patches. The argumentation structure is captured using Artoo (www.york.ac.uk/ycil/software/artoo), our Web-based tool for constructing fitness-for-purpose arguments, using a notation based on the safety-critical goal structuring notation. We show how argumentation helps in making the design and structured analysis of a model transparent, capturing the reasoning behind the inclusion or exclusion of each biological feature and recording assumptions, as well as pointing to evidence supporting model-derived conclusions. PMID:25589574
Using argument notation to engineer biological simulations with increased confidence.
Alden, Kieran; Andrews, Paul S; Polack, Fiona A C; Veiga-Fernandes, Henrique; Coles, Mark C; Timmis, Jon
2015-03-06
The application of computational and mathematical modelling to explore the mechanics of biological systems is becoming prevalent. To significantly impact biological research, notably in developing novel therapeutics, it is critical that the model adequately represents the captured system. Confidence in adopting in silico approaches can be improved by applying a structured argumentation approach, alongside model development and results analysis. We propose an approach based on argumentation from safety-critical systems engineering, where a system is subjected to a stringent analysis of compliance against identified criteria. We show its use in examining the biological information upon which a model is based, identifying model strengths, highlighting areas requiring additional biological experimentation and providing documentation to support model publication. We demonstrate our use of structured argumentation in the development of a model of lymphoid tissue formation, specifically Peyer's Patches. The argumentation structure is captured using Artoo (www.york.ac.uk/ycil/software/artoo), our Web-based tool for constructing fitness-for-purpose arguments, using a notation based on the safety-critical goal structuring notation. We show how argumentation helps in making the design and structured analysis of a model transparent, capturing the reasoning behind the inclusion or exclusion of each biological feature and recording assumptions, as well as pointing to evidence supporting model-derived conclusions.
Shorthand notation for lipid structures derived from mass spectrometry.
Liebisch, Gerhard; Vizcaíno, Juan Antonio; Köfeler, Harald; Trötzmüller, Martin; Griffiths, William J; Schmitz, Gerd; Spener, Friedrich; Wakelam, Michael J O
2013-06-01
There is a need for a standardized, practical annotation for structures of lipid species derived from mass spectrometric approaches; i.e., for high-throughput data obtained from instruments operating in either high- or low-resolution modes. This proposal is based on common, officially accepted terms and builds upon the LIPID MAPS terminology. It aims to add defined levels of information below the LIPID MAPS nomenclature, as detailed chemical structures, including stereochemistry, are usually not automatically provided by mass spectrometric analysis. To this end, rules for lipid species annotation were developed that reflect the structural information derived from the analysis. For example, commonly used head group-specific analysis of glycerophospholipids (GP) by low-resolution instruments is neither capable of differentiating the fatty acids linked to the glycerol backbone nor able to define their bond type (ester, alkyl-, or alk-1-enyl-ether). This and other missing structural information is covered by the proposed shorthand notation presented here. Beyond GPs, we provide shorthand notation for fatty acids/acyls (FA), glycerolipids (GL), sphingolipids (SP), and sterols (ST). In summary, this defined shorthand nomenclature provides a standard methodology for reporting lipid species from mass spectrometric analysis and for constructing databases.
In vitro evaluation of corrosion and cytotoxicity of orthodontic brackets.
Costa, M T; Lenza, M A; Gosch, C S; Costa, I; Ribeiro-Dias, F
2007-05-01
The corrosion resistance of AISI 304 stainless steel (AISI 304 SS) and manganese stainless steel (low-nickel SS) brackets in artificial saliva was investigated. The cytotoxic effects of their corrosion products on L929 cell culture were compared by two assays, crystal violet, to evaluate cell viability, and MTT (3-[4,5-dimethylthiazol-2-yl]2,5-diphenyltetrazolium bromide), for cell metabolism and proliferation. The atomic absorption spectroscopic analysis of the corrosion products demonstrated that nickel and manganese ion concentrations were higher for the AISI 304 SS-bracket immersion solution as compared with the low-nickel SS brackets. Scanning electron microscopy and energy-dispersive spectroscopy demonstrated less corrosion resistance for the AISI 304 SS brackets. Although none of the bracket extracts altered L929 cell viability or morphology, the AISI 304 SS-bracket extracts decreased cellular metabolism slightly. The results indicated that the low-nickel SS presents better in vitro biocompatibility than AISI 304 SS brackets. Abbreviations used: AISI, American Iron and Steel Institute; EDS, energy-dispersive spectroscopy; OD, optical density; ISO, International Organization for Standardization; MTT, (3-{4,5 dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; NiSO(4), nickel sulfate; SEM, standard error of the mean; WHO, World Health Organization; and TNF, tumor necrosis factor.
Preliminary Process Design of ITER ELM Coil Bracket Brazing
NASA Astrophysics Data System (ADS)
LI, Xiangbin; SHI, Yi
2015-03-01
With the technical requirement of the International Thermonuclear Experimental Reactor (ITER) project, the manufacture and assembly technology of the mid Edge Localized Modes (ELM) coil was developed by the Institute of Plasma Physics, Chinese Academy of Science (ASIPP). As the gap between the bracket and the Stainless Steel jacketed and Mineral Insulated Conductor (SSMIC) can be larger than 0.5 mm instead of 0.01 mm to 0.1 mm as in normal industrial cases, the process of mid ELM coil bracket brazing to the SSMICT becomes quiet challenging, from a technical viewpoint. This paper described the preliminary design of ELM coil bracket brazing to the SSMIC process, the optimal bracket brazing curve and the thermal simulation of the bracket furnace brazing method developed by ANSYS. BAg-6 foil (Bag50Cu34Zn16) plus BAg-1a paste (Bag45CuZnCd) solders were chosen as the brazing filler. By testing an SSMICT prototype, it is shown that the average gap between the bracket and the SSMIC could be controlled to 0.2-0.3 mm, and that there were few voids in the brazing surface. The results also verified that the preliminary design had a favorable heat conducting performance in the bracket.
Color stability of ceramic brackets immersed in potentially staining solutions
Guignone, Bruna Coser; Silva, Ludimila Karsbergen; Soares, Rodrigo Villamarim; Akaki, Emilio; Goiato, Marcelo Coelho; Pithon, Matheus Melo; Oliveira, Dauro Douglas
2015-01-01
OBJECTIVE: To assess the color stability of five types of ceramic brackets after immersion in potentially staining solutions. METHODS: Ninety brackets were divided into 5 groups (n = 18) according to brackets commercial brands and the solutions in which they were immersed (coffee, red wine, coke and artificial saliva). The brackets assessed were Transcend (3M/Unitek, Monrovia, CA, USA), Radiance (American Orthodontics, Sheboygan, WI, USA), Mystique (GAC International Inc., Bohemia, NY, USA) and Luxi II (Rocky Mountain Orthodontics, Denver, CO, USA). Chromatic changes were analyzed with the aid of a reflectance spectrophotometer and by visual inspection at five specific time intervals. Assessment periods were as received from the manufacturer (T0), 24 hours (T1), 72 hours (T2), as well as 7 days (T3) and 14 days (T4) of immersion in the aforementioned solutions. Results were submitted to statistical analysis with ANOVA and Bonferroni correction, as well as to a multivariate profile analysis for independent and paired samples with significance level set at 5%. RESULTS: The duration of the immersion period influenced color alteration of all tested brackets, even though these changes could not always be visually observed. Different behaviors were observed for each immersion solution; however, brackets immersed in one solution progressed similarly despite minor variations. CONCLUSIONS: Staining became more intense over time and all brackets underwent color alterations when immersed in the aforementioned solutions. PMID:26352842
Impact of Orthodontic Brackets on the Intraoral Scan Data Accuracy
Park, Ji-Man; Choi, Shin-Ae; Myung, Ji-Yun; Chun, Youn-Sic
2016-01-01
This study aims to compare the impact of buccal and lingual brackets on the accuracy of dental arch data acquired by 4 different digital intraoral scanners. Two pairs of dental casts, one with buccal brackets and the other with lingual brackets, were used. Digital measurements of the 3D images were compared to the actual measurements of the dental models, which were considered standard values. The horizontal measurements included intercanine widths and intermolar widths. The Mann–Whitney U test was performed for comparisons. iTero® and Trios® both showed high accuracy with relatively small maximum deviation of measurements. iTero showed a significantly higher accuracy in most of the arch width measurements on the buccal bracket model than on the lingual model (P < 0.05). Zfx IntraScan® and E4D Dentist® produced maximum deviations of more than 2 mm from both the buccal and the lingual bracket models. After comparing the degree of distortion of the arch on the digital scans with actual measurements of the same models, iTero and Trios proved to be excellent in terms of trueness and precision. Nevertheless, digital intraoral scanners should be used more cautiously in arches with lingual brackets than in those with buccal brackets. PMID:27999798
A Proposal of a Color Music Notation System on a Single Melody for Music Beginners
ERIC Educational Resources Information Center
Kuo, Yi-Ting; Chuang, Ming-Chuen
2013-01-01
Music teachers often encounter obstructions in teaching beginners in music reading. Conventional notational symbols require beginners to spend significant amount of time in memorizing, which discourages learning at early stage. This article proposes a newly-developed color music notation system that may improve the recognition of the staff and the…
Using Graphical Notations to Assess Children's Experiencing of Simple and Complex Musical Fragments
ERIC Educational Resources Information Center
Verschaffel, Lieven; Reybrouck, Mark; Janssens, Marjan; Van Dooren, Wim
2010-01-01
The aim of this study was to analyze children's graphical notations as external representations of their experiencing when listening to simple sonic stimuli and complex musical fragments. More specifically, we assessed the impact of four factors on children's notations: age, musical background, complexity of the fragment, and most salient…
From Depiction to Notation: How Children Use Symbols to Represent Objects and Events
ERIC Educational Resources Information Center
Eskritt, Michelle; Olson, David
2012-01-01
The purpose of the present study was to explore children's understanding of external symbols by examining the relationship between children's production and comprehension of graphic notations and verbal messages. Fifty-six children between the ages of 5 and 7 years were asked to produce both notations and a spoken message relaying to their…
ERIC Educational Resources Information Center
Teubal, E.; Dockrell, J.E.
2005-01-01
This paper addresses the emergence of children's early use of numerical notation. Children's notations for different forms of numerical input were investigated and the development of these forms is described. Eighty children, 3.0-5.8, recorded the results of a throw of a die in a game. Numerosities were represented with digits or dots on the die.…
ERIC Educational Resources Information Center
Hewitt, Dave
2014-01-01
This article analyzes the use of the software Grid Algebra with a mixed ability class of 21 nine-to-ten-year-old students who worked with complex formal notation involving all four arithmetic operations. Unlike many other models to support learning, Grid Algebra has formal notation ever present and allows students to "look through" that…
ERIC Educational Resources Information Center
Thompson, Patrick W.
1992-01-01
Fourth grade children (n=20) were matched on a pretest and randomly assigned to either a wooden base-10 block or computerized microworld group. Instruction was designed to establish relationships between notation and meaning, extending whole number numeration to decimal numeration. Neither group changed whole-number notational methods nor had…
From Depiction to Notation: How Children Use Symbols to Represent Objects and Events
ERIC Educational Resources Information Center
Eskritt, Michelle; Olson, David
2012-01-01
The purpose of the present study was to explore children's understanding of external symbols by examining the relationship between children's production and comprehension of graphic notations and verbal messages. Fifty-six children between the ages of 5 and 7 years were asked to produce both notations and a spoken message relaying to their…
ERIC Educational Resources Information Center
Hewitt, Dave
2014-01-01
This article analyzes the use of the software Grid Algebra with a mixed ability class of 21 nine-to-ten-year-old students who worked with complex formal notation involving all four arithmetic operations. Unlike many other models to support learning, Grid Algebra has formal notation ever present and allows students to "look through" that…
19 CFR 125.34 - Countersigning of documents and notation of bad order or discrepancy.
Code of Federal Regulations, 2010 CFR
2010-04-01
... 19 Customs Duties 1 2010-04-01 2010-04-01 false Countersigning of documents and notation of bad... and Receipt § 125.34 Countersigning of documents and notation of bad order or discrepancy. When a... and shall note thereon any bad order or discrepancy. When available, the importing carrier's...
19 CFR 125.34 - Countersigning of documents and notation of bad order or discrepancy.
Code of Federal Regulations, 2011 CFR
2011-04-01
... 19 Customs Duties 1 2011-04-01 2011-04-01 false Countersigning of documents and notation of bad... and Receipt § 125.34 Countersigning of documents and notation of bad order or discrepancy. When a... and shall note thereon any bad order or discrepancy. When available, the importing carrier's...
Wiswesser Line Notation: Simplified Techniques for Converting Chemical Structures to WLN.
Koniver, D A; Wiswesser, W J; Usdin, E
1972-06-30
Techniques have been developed for the generation of Wiswesser Line Notations (WLN), which require knowledge neither of rules for manual conversion of structures to line notations nor of computer programming. The desired WLN are obtained simply by drawing the structures of the compounds of interest on a tablet, which is linked to an appropriately programmned computer.
Using Design Principles to Consider Representation of the Hand in Some Notation Systems
ERIC Educational Resources Information Center
Hochgesang, Julie A.
2014-01-01
Linguists have long recognized the descriptive limitations of Stokoe notation, currently the most commonly used system for phonetic or phonological transcription, but continue using it because of its widespread influence (e.g., Siedlecki and Bonvillian, 2000). With the emergence of newer notation systems, the field will benefit from a discussion…
A Proposal of a Color Music Notation System on a Single Melody for Music Beginners
ERIC Educational Resources Information Center
Kuo, Yi-Ting; Chuang, Ming-Chuen
2013-01-01
Music teachers often encounter obstructions in teaching beginners in music reading. Conventional notational symbols require beginners to spend significant amount of time in memorizing, which discourages learning at early stage. This article proposes a newly-developed color music notation system that may improve the recognition of the staff and the…
19 CFR 125.34 - Countersigning of documents and notation of bad order or discrepancy.
Code of Federal Regulations, 2012 CFR
2012-04-01
... 19 Customs Duties 1 2012-04-01 2012-04-01 false Countersigning of documents and notation of bad... and Receipt § 125.34 Countersigning of documents and notation of bad order or discrepancy. When a... and shall note thereon any bad order or discrepancy. When available, the importing carrier's tally...
19 CFR 125.34 - Countersigning of documents and notation of bad order or discrepancy.
Code of Federal Regulations, 2013 CFR
2013-04-01
... 19 Customs Duties 1 2013-04-01 2013-04-01 false Countersigning of documents and notation of bad... and Receipt § 125.34 Countersigning of documents and notation of bad order or discrepancy. When a... and shall note thereon any bad order or discrepancy. When available, the importing carrier's tally...
19 CFR 125.34 - Countersigning of documents and notation of bad order or discrepancy.
Code of Federal Regulations, 2014 CFR
2014-04-01
... 19 Customs Duties 1 2014-04-01 2014-04-01 false Countersigning of documents and notation of bad... and Receipt § 125.34 Countersigning of documents and notation of bad order or discrepancy. When a... and shall note thereon any bad order or discrepancy. When available, the importing carrier's tally...
19 CFR 141.90 - Notation of tariff classification and value on invoice.
Code of Federal Regulations, 2013 CFR
2013-04-01
... 19 Customs Duties 2 2013-04-01 2013-04-01 false Notation of tariff classification and value on invoice. 141.90 Section 141.90 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY (CONTINUED) ENTRY OF MERCHANDISE Invoices § 141.90 Notation of tariff...
19 CFR 141.90 - Notation of tariff classification and value on invoice.
Code of Federal Regulations, 2011 CFR
2011-04-01
... 19 Customs Duties 2 2011-04-01 2011-04-01 false Notation of tariff classification and value on invoice. 141.90 Section 141.90 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY (CONTINUED) ENTRY OF MERCHANDISE Invoices § 141.90 Notation of tariff...
ERIC Educational Resources Information Center
Elyagutu, Dilek Cantekin; Hazar, Muhsin
2017-01-01
In this research, Movement Notation (Laban) and Traditional Method in Folk dance Teaching were compared in terms of learning success. Movement notation group (n = 14) and Traditional group (n = 14) consisting of students from the S.U. State Conservatory Turkish Folk Dance Department were formed. During the 14-week-long study, the symbols of the…
Using Design Principles to Consider Representation of the Hand in Some Notation Systems
ERIC Educational Resources Information Center
Hochgesang, Julie A.
2014-01-01
Linguists have long recognized the descriptive limitations of Stokoe notation, currently the most commonly used system for phonetic or phonological transcription, but continue using it because of its widespread influence (e.g., Siedlecki and Bonvillian, 2000). With the emergence of newer notation systems, the field will benefit from a discussion…
Survival analysis with clustered observations of orthodontic brackets.
Petracci, Elisabetta; Farella, Mauro; Galeone, Carlotta; Albano, Alessandra; Ferraroni, Monica; Decarli, Adriano
2009-12-10
Failures in the bonding of dental bracket are a big concern for orthodontists. Clinical experience suggests that some patients are more prone than others to experience failures. Therefore, it can be expected that in statistical analysis of orthodontic bracket failures, the usual assumption of independence between the observations is violated. An approach to overcome this problem is to apply the frailty model, in which the association between failure times is modelled with a random-effect term (i.e. frailty). We postulated that brackets of the same subject share the same frailty, that is, a latent common group effect, due to some unknown or unobserved covariates.The aim of this study was to investigate possible risk factors related to bracket failure using Cox proportional hazards model with a shared frailty term and to compare the results with those obtained using a basic Cox proportional hazards model.Survival data for 1677 brackets were obtained from a cohort of 54 females (mean age +/- SD: 13.3+/-4.8 yrs) and 46 males (mean age +/-SD: 13.1+/-3.8 yrs) over a eight-year period. Age, gender, vertical craniofacial morphology and anatomical location of brackets were entered into Cox models as covariates. The findings indicated that bracket failure was significantly affected by tooth position within the dental arch, with the highest failure risk in maxillary posterior region. Age, gender and vertical craniofacial morphology did not affect bracket failure. A Cox proportional hazards model with a shared frailty term represents a useful approach for modelling orthodontic bracket failures. Copyright (c) 2009 John Wiley & Sons, Ltd.
Recent Updates to the CFD General Notation System (CGNS)
NASA Technical Reports Server (NTRS)
Rumsey, Christopher L.; Wedan, Bruce; Hauser, Thomas; Poinot, Marc
2012-01-01
The CFD General Notation System (CGNS) - a general, portable, and extensible standard for the storage and retrieval of computational fluid dynamics (CFD) analysis data has been in existence for more than a decade (Version 1.0 was released in May 1998). Both structured and unstructured CFD data are covered by the standard, and CGNS can be easily extended to cover any sort of data imaginable, while retaining backward compatibility with existing CGNS data files and software. Although originally designed for CFD, it is readily extendable to any field of computational analysis. In early 2011, CGNS Version 3.1 was released, which added significant capabilities. This paper describes these recent enhancements and highlights the continued usefulness of the CGNS methodology.
How to improve skin notation. Position paper from a workshop.
Sartorelli, Pietro; Ahlers, Heinz W; Alanko, Kristiina; Chen-Peng, Chen; Cherrie, John W; Drexler, Hans; Kezic, Sanja; Johanson, Gunnar; Larese Filon, Francesca; Maina, Giovanni; Montomoli, Loretta; Nielsen, Jesper Bo
2007-12-01
The ICOH Scientific Committee on Occupational and Environmental Dermatoses organized an International Workshop on "Dermal risk assessment at workplace" with the aim of focussing on the different ways of approaching the concept of skin notation (S) for chemicals. The Workshop participants presented their ideas on several aspects of S such as the problems related to the absorption through the compromised skin, the different approaches to S and models that can be used as alternatives to S. Participants agreed to produce a position paper with the goal of exploring the actions needed to improve the S system towards international harmonization. They consider that further discussions are needed to obtain an international consensus, but at the same time they believe that by improving and harmonizing systems for setting S we can make an important contribution to improving health of people with potential dermal exposure to chemicals at work.
Definition of the Neutrosophic Probability
NASA Astrophysics Data System (ADS)
Smarandache, Florentin
2014-03-01
Neutrosophic probability (or likelihood) [1995] is a particular case of the neutrosophic measure. It is an estimation of an event (different from indeterminacy) to occur, together with an estimation that some indeterminacy may occur, and the estimation that the event does not occur. The classical probability deals with fair dice, coins, roulettes, spinners, decks of cards, random works, while neutrosophic probability deals with unfair, imperfect such objects and processes. For example, if we toss a regular die on an irregular surface which has cracks, then it is possible to get the die stuck on one of its edges or vertices in a crack (indeterminate outcome). The sample space is in this case: {1, 2, 3, 4, 5, 6, indeterminacy}. So, the probability of getting, for example 1, is less than 1/6. Since there are seven outcomes. The neutrosophic probability is a generalization of the classical probability because, when the chance of determinacy of a stochastic process is zero, these two probabilities coincide. The Neutrosophic Probability that of an event A occurs is NP (A) = (ch (A) , ch (indetA) , ch (A ̲)) = (T , I , F) , where T , I , F are subsets of [0,1], and T is the chance that A occurs, denoted ch(A); I is the indeterminate chance related to A, ch(indetermA) ; and F is the chance that A does not occur, ch (A ̲) . So, NP is a generalization of the Imprecise Probability as well. If T, I, and F are crisp numbers then: - 0 <= T + I + F <=3+ . We used the same notations (T,I,F) as in neutrosophic logic and set.
Bond strengths evaluation of laser ceramic bracket debonding
NASA Astrophysics Data System (ADS)
Dostalová, T.; Jelinková, H.; Šulc, J.; Němec, M.; Fibrich, M.; Jelínek, M.; Michalík, P.; Bučková, M.
2012-09-01
Ceramic brackets often used for an orthodontic treatment can lead to problems such as enamel tear outs because of their low fracture resistance and high bond strengths. Therefore the aim of our study was to investigate the positive laser radiation effect on bracket debonding. Moreover, the influence of the enamel shape surface under the bracket and laser radiation power on the debonding strength was investigated. The source of the radiation was the longitudinally diode-pumped Tm:YAP laser operating at 1997 nm. To eliminate the tooth surface roughness the flat enamel surface was prepared artificially and the bracket was bonded on it. The debonding was accomplished by Tm:YAP laser radiation with different the power value while recording the temperature rise in the pulp. To simulate the debonding process in vivo the actual bond strength was measured by the digital force gauge. The results were analyzed by scanning electron microscope.
18. DETAIL VIEW OF RAILING BRACKETING AND DECORATIVE ART DECO ...
18. DETAIL VIEW OF RAILING BRACKETING AND DECORATIVE ART DECO FEATURES. - East Pendleton Overcrossing, Southeast Court Avenue between Southeast Tenth & Southeast Fifteenth Streets, Pendleton Highway (U.S. Route 30), Pendleton, Umatilla County, OR
Detail of post, brackets, railing, and spindle work frieze; camera ...
Detail of post, brackets, railing, and spindle work frieze; camera facing northeast. - Mare Island Naval Shipyard, Bandstand, Eighth Street, south side between Railroad Avenue & Walnut Avenue, Vallejo, Solano County, CA
Er:YAG laser metal and ceramic bracket debonding
NASA Astrophysics Data System (ADS)
Dostálová, Tat'jana; Remeš, Marek; Jelínková, Helena; Å ulc, Jan; Němec, Michal; Vyhlídal, David
2016-02-01
The goal of the study was investigation of Er:YAG radiation (wavelength 2.94 μm) interaction with various metal and ceramic brackets and adhesive materials. The source of radiation was a free-running Er: YAG laser generating pulses with energy 280 mJ, 250 μs long and repetition rate 6 Hz (mean power 1.7 W). During the treatment lasting 140 s, water cooling was implemented and only the brackets were irradiated. It has been observed that the brackets were removed easily after the Er:YAG laser irradiation, and temperature rise was limited also for metal brackets. SEM investigation has confirmed less damage of enamel in comparison with non-irradiated samples.
DETAIL OF PLATFORM SUPPORT BRACKET, ALTITUDE CHAMBER L, FACING NORTHWEST ...
DETAIL OF PLATFORM SUPPORT BRACKET, ALTITUDE CHAMBER L, FACING NORTHWEST - Cape Canaveral Air Force Station, Launch Complex 39, Altitude Chambers, First Street, between Avenue D and Avenue E, Cape Canaveral, Brevard County, FL
14. DETAIL VIEW OF THE CANTILEVER & 'S' BRACKETS AND ...
14. DETAIL VIEW OF THE CANTILEVER & 'S' BRACKETS AND THE SOUTH HANDRAIL, PANEL 1, NEAR THE SOUTHEAST ABUTMENT, LOOKING NORTHWEST Harms - Benton Street Bridge, Spanning Iowa River at Benton Street, Iowa City, Johnson County, IA
Detail of castiron bracket supporting overhang on Train Shed. ...
Detail of cast-iron bracket supporting overhang on Train Shed. - Central of Georgia Railway, Passenger Station & Train Shed, Corner of Louisville (Railroad) Road & West Broad Street, Savannah, Chatham County, GA
Oblique view of north side showing bracketed window awnings, main ...
Oblique view of north side showing bracketed window awnings, main entry, and mission coping, facing southeast. - Albrook Air Force Station, Parachute & Armament Building, 200 feet north of Andrews Boulevard, Balboa, Former Panama Canal Zone, CZ
Detail of southwest corner showing rear double door entry, bracketed ...
Detail of southwest corner showing rear double door entry, bracketed window awnings, and decorative parapet coping, facing northeast. - Albrook Air Force Station, Parachute & Armament Building, 200 feet north of Andrews Boulevard, Balboa, Former Panama Canal Zone, CZ
44. Detail, bridge land span outboard girder brackets carrying utility ...
44. Detail, bridge land span outboard girder brackets carrying utility conduit. Structure rests on granite blocks mounted on granite piers. - Broadway Bridge, Spanning Foundry Street, MBTA Yard, Fort Point Channel, & Lehigh Street, Boston, Suffolk County, MA
Detail of large, brick columns and bracket inside Electrical Shop ...
Detail of large, brick columns and bracket inside Electrical Shop - Central of Georgia Railway, Savannah Repair Shops & Terminal Facilities, Electrical Shop, Bounded by West Broad, Jones, West Boundary & Hull Streets, Savannah, Chatham County, GA
15. MACHINERY DETAILS: LATCH WHEEL BRACKET, LATCH POCKET, LOCK BAR, ...
15. MACHINERY DETAILS: LATCH WHEEL BRACKET, LATCH POCKET, LOCK BAR, LATCH CRADLE, SPLIT COLLAR, ETC. - Niantic River Swing Bridge, Spanning Niantic River between East Lyme & Waterford, Old Lyme, New London County, CT
Detail of diagonal end post support bracket mounted to east ...
Detail of diagonal end post support bracket mounted to east face of track girder, east span. View south - New York, New Haven & Hartford Railroad, Fort Point Channel Rolling Lift Bridge, Spanning Fort Point Channel, Boston, Suffolk County, MA
Detail view of door surround, note bracket & ghost of ...
Detail view of door surround, note bracket & ghost of (former) arched opening in the brickwork beside it - Leonard Mackall House, 1686 Thirty-Fourth Street, Northwest, Washington, District of Columbia, DC
Detail view of bracket, arched window and eagle from building ...
Detail view of bracket, arched window and eagle from building 18 section. Jet Lowe, Haer staff photographer, summer 1995 - Naval Base Philadelphia-Philadelphia Naval Shipyard, Machine Shops, League Island, Philadelphia, Philadelphia County, PA
Ligand "Brackets" for Ga-Ga Bond.
Fedushkin, Igor L; Skatova, Alexandra A; Dodonov, Vladimir A; Yang, Xiao-Juan; Chudakova, Valentina A; Piskunov, Alexander V; Demeshko, Serhiy; Baranov, Evgeny V
2016-09-06
The reactivity of digallane (dpp-Bian)Ga-Ga(dpp-Bian) (1) (dpp-Bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene) toward acenaphthenequinone (AcQ), sulfur dioxide, and azobenzene was investigated. The reaction of 1 with AcQ in 1:1 molar ratio proceeds via two-electron reduction of AcQ to give (dpp-Bian)Ga(μ2-AcQ)Ga(dpp-Bian) (2), in which diolate [AcQ](2-) acts as "bracket" for the Ga-Ga bond. The interaction of 1 with AcQ in 1:2 molar ratio proceeds with an oxidation of the both dpp-Bian ligands as well as of the Ga-Ga bond to give (dpp-Bian)Ga(μ2-AcQ)2Ga(dpp-Bian) (3). At 330 K in toluene complex 2 decomposes to give compounds 3 and 1. The reaction of complex 2 with atmospheric oxygen results in oxidation of a Ga-Ga bond and affords (dpp-Bian)Ga(μ2-AcQ)(μ2-O)Ga(dpp-Bian) (4). The reaction of digallane 1 with SO2 produces, depending on the ratio (1:2 or 1:4), dithionites (dpp-Bian)Ga(μ2-O2S-SO2)Ga(dpp-Bian) (5) and (dpp-Bian)Ga(μ2-O2S-SO2)2Ga(dpp-Bian) (6). In compound 5 the Ga-Ga bond is preserved and supported by dithionite dianionic bracket. In compound 6 the gallium centers are bridged by two dithionite ligands. Both 5 and 6 consist of dpp-Bian radical anionic ligands. Four-electron reduction of azobenzene with 1 mol equiv of digallane 1 leads to complex (dpp-Bian)Ga(μ2-NPh)2Ga(dpp-Bian) (7). Paramagnetic compounds 2-7 were characterized by electron spin resonance spectroscopy, and their molecular structures were established by single-crystal X-ray analysis. Magnetic behavior of compounds 2, 5, and 6 was investigated by superconducting quantum interference device technique in the range of 2-295 K.
NASA Astrophysics Data System (ADS)
Jaynes, E. T.; Bretthorst, G. Larry
2003-04-01
Foreword; Preface; Part I. Principles and Elementary Applications: 1. Plausible reasoning; 2. The quantitative rules; 3. Elementary sampling theory; 4. Elementary hypothesis testing; 5. Queer uses for probability theory; 6. Elementary parameter estimation; 7. The central, Gaussian or normal distribution; 8. Sufficiency, ancillarity, and all that; 9. Repetitive experiments, probability and frequency; 10. Physics of 'random experiments'; Part II. Advanced Applications: 11. Discrete prior probabilities, the entropy principle; 12. Ignorance priors and transformation groups; 13. Decision theory: historical background; 14. Simple applications of decision theory; 15. Paradoxes of probability theory; 16. Orthodox methods: historical background; 17. Principles and pathology of orthodox statistics; 18. The Ap distribution and rule of succession; 19. Physical measurements; 20. Model comparison; 21. Outliers and robustness; 22. Introduction to communication theory; References; Appendix A. Other approaches to probability theory; Appendix B. Mathematical formalities and style; Appendix C. Convolutions and cumulants.
Microstructural and mechanical characterization of contemporary lingual orthodontic brackets.
Zinelis, Spiros; Sifakakis, Iosif; Katsaros, Christos; Eliades, Theodore
2014-08-01
To investigate the composition and the microstructural and mechanical characterization of three different types of lingual brackets. Incognito™ (3M Unitek), In-Ovation L (DENTSPLY GAC) and STb™ (Light Lingual System, ORMCO) lingual brackets were studied under the scanning electron microscope employing backscattered electron imaging and their elemental composition was analysed by energy-dispersive X-ray microanalysis. Additionally, Vickers hardness was assessed using a universal hardness-testing machine, and the indentation modulus was measured according to instrumented indentation test. Two-way analysis of variance was conducted employing bracket type and location (base and wing) as discriminating variable. Significant differences among groups were allocated by post hoc Student-Newman-Keuls multiple comparison analysis at 95% level of significance. Three different phases were identified for Incognito and In-Ovation L bracket based on mean atomic number contrast. On the contrary, STb did not show mean atomic contrast areas and thus it is recognized as a single phase. Incognito is a one-piece bracket with the same structure in wing and base regions. Incognito consists mainly of noble metals while In-Ovation L and STb show similar formulations of ferrous alloys in wing and base regions. No significant differences were found between ferrous brackets in hardness and modulus values, but there were significant differences between wing and base regions. Incognito illustrated intermediate values with significant differences from base and wing values of ferrous brackets. Significant differences exist in microstructure, elemental composition, and mechanical properties among the brackets tested; these might have a series of clinical implications during mechanotherapy. © The Author 2013. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.
Corrosion behavior of self-ligating and conventional metal brackets
Maia, Lúcio Henrique Esmeraldo Gurgel; Lopes Filho, Hibernon; Ruellas, Antônio Carlos de Oliveira; Araújo, Mônica Tirre de Souza; Vaitsman, Delmo Santiago
2014-01-01
Objective To test the null hypothesis that the aging process in self-ligating brackets is not higher than in conventional brackets. Methods Twenty-five conventional (GN-3M/Unitek; GE-GAC; VE-Aditek) and 25 self-ligating (SCs-3M/Unitek; INs-GAC; ECs-Aditek) metal brackets from three manufacturers (n = 150) were submitted to aging process in 0.9% NaCl solution at a constant temperature of 37 ± 1ºC for 21 days. The content of nickel, chromium and iron ions in the solution collected at intervals of 7, 14 and 21 days was quantified by atomic absorption spectrophotometry. After the aging process, the brackets were analyzed by scanning electron microscopy (SEM) under 22X and 1,000X magnifications. Results Comparison of metal release in self-ligating and conventional brackets from the same manufacturer proved that the SCs group released more nickel (p < 0.05) than the GN group after 7 and 14 days, but less chromium (p < 0.05) after 14 days and less iron (p < 0.05) at the three experimental time intervals. The INs group released less iron (p < 0.05) than the GE group after 7 days and less nickel, chromium and iron (p < 0.05) after 14 and 21 days. The ECs group released more nickel, chromium and iron (p < 0.05) than the VE group after 14 days, but released less nickel and chromium (p < 0.05) after 7 days and less chromium and iron (p < 0.05) after 21 days. The SEM analysis revealed alterations on surface topography of conventional and self-ligating brackets. Conclusions The aging process in self-ligating brackets was not greater than in conventional brackets from the same manufacturer. The null hypothesis was accepted. PMID:24945521
Clinical evaluation of the failure rates of metallic brackets
ROMANO, Fábio Lourenço; CORRER, Américo Bortolazzo; CORRER-SOBRINHO, Lourenço; MAGNANI, Maria Beatriz Borges de Araújo; RUELLAS, Antônio Carlos de Oliveira
2012-01-01
Objectives The aim of this study was to evaluate in vivo the bonding of metallic orthodontic brackets with different adhesive systems. Material and Methods Twenty patients (10.5-15.1 years old) who had sought corrective orthodontic treatment at a University Orthodontic Clinic were evaluated. Brackets were bonded from the right second premolar to the left second premolar in the upper and lower arches using: Orthodontic Concise, conventional Transbond XT, Transbond XT without primer, and Transbond XT associated with Transbond Plus Self-etching Primer (TPSEP). The 4 adhesive systems were used in all patients using a split-mouth design; each adhesive system was used in one quadrant of each dental arch, so that each group of 5 patients received the same bonding sequence. Initial archwires were inserted 1 week after bracket bonding. The number of bracket failures for each adhesive system was quantified over a 6-month period. Results The number of debonded brackets was: 8- Orthodontic Concise, 2- conventional Transbond XT, 9- Transbond XT without primer, and 1- Transbond XT + TPSEP. By using the Kaplan-Meier methods, statistically significant differences were found between the materials (p=0.0198), and the Logrank test identified these differences. Conventional Transbond XT and Transbond XT + TPSEP adhesive systems were statistically superior to Orthodontic Concise and Transbond XT without primer (p<0.05). There was no statistically significant difference between the dental arches (upper and lower), between the dental arch sides (right and left), and among the quadrants. Conclusions The largest number of bracket failures occurred with Orthodontic Concise and Transbond XT without primer systems and few bracket failures occurred with conventional Transbond XT and Transbond XT+TPSEP. More bracket failures were observed in the posterior region compared with the anterior region. PMID:22666842
On Goldman bracket for G 2 gauge group
NASA Astrophysics Data System (ADS)
Chowdhury, S. Hasibul Hassan
2016-02-01
In this paper, we obtain an infinite dimensional Lie algebra of exotic gauge invariant observables that is closed under Goldman-type bracket associated with monodromy matrices of flat connections on a compact Riemann surface for G 2 gauge group. As a byproduct, we give an alternative derivation of known Goldman bracket for classical gauge groups GL ( n, ℝ), SL( n, ℝ), U( n), SU( n), Sp(2 n, ℝ) and SO( n).
Assessment of enamel damage after removal of ceramic brackets.
Kitahara-Céia, Flávia Mitiko Fernandes; Mucha, José Nelson; Marques dos Santos, Paulo Acioly
2008-10-01
Since the introduction of ceramic brackets, research has been performed to evaluate enamel damage caused during their removal. One problem in comparing treated and control groups is the absence of assurance that the surfaces were undamaged before the brackets were bonded and debonded, or that superficial treatment applied to the enamel could hinder damage detection. The aim of this in-vitro study was to evaluate enamel injuries during debonding of 3 types of ceramic brackets. Forty-five premolars, extracted for orthodontic purposes, were divided into 3 groups of 15. The enamel surfaces were photographed with a magnifying loupe (60 times) in an optical stereomicroscope (Stemi 2000-C, Zeiss, Oberkochen, Germany) with a digital camera. A different type of backet was bonded and debonded in each group: mechanical retention, mechanical retention with a polymer base, and chemical retention. After debonding, the surfaces were again photographed. The photographs were evaluated for quality of enamel surface according to a predetermined scale. The results were tested by method error and the chi-square test. The damage evaluation comparing the same surface before bonding and after debonding showed no significant statistical difference between the mechanical retention group and the polymer base retention group. There was a significant statistical difference (P <0.05) for the chemical adhesion ceramic bracket group. The difference between the enamel surfaces before bonding and after debonding brackets with chemical retention was statistically significant; bonding and debonding these brackets resulted in enamel damage.
Notation Confusion of Symmetry Species for Molecules with Several Large-Amplitude Internal Motions
NASA Astrophysics Data System (ADS)
Groner, P.
2011-06-01
The Mulliken convention has become the standard notation for symmetry species (irreducible representations) of point groups for quasi-rigid molecules. No such convention exists for symmetry species of symmetry groups for semi-rigid or non-rigid molecules with large amplitude internal motions (LAMs). As a result, we have a situation where we create notations in a do-it-yourself fashion or adopt them from the literature, sometimes even without proper reference to its derivation or to the character table on which it is based. This may be just a nuisance for those who are comfortable enough with group theory and molecular symmetry groups to figure "it" out, but it represents a real problem for everybody else. The notation confusion is illustrated with examples from the literature (both old and new) on molecules with two or more LAMs. Most authors use the notation introduced by Myers and Wilson for molecules such as acetone or propane. No universal notation is in use for molecules with two methyl groups but lower overall symmetry. For example, the notation G_1_8 is used for one of these groups. As it turns out, different people use the same notation for different groups. This presentation is an attempt to bring some light into the dark and to combat confusion with a call for an anti-confusion convention. R. S. Mulliken, Phys. Rev. 43, 279 (1933). R. J. Myers, E. B. Wilson, J. Chem. Phys. 33, 186 (1960).
Kang, Da-Young; Choi, Sung-Hwan; Cha, Jung-Yul; Hwang, Chung-Ju
2013-07-01
To investigate the three-dimensional structural features of three types of mechanically retentive ceramic bracket bases. One type of stainless steel (MicroArch, Tomy, Tokyo, Japan) and three types of ceramic maxillary right central incisor brackets-Crystaline MB (Tomy), INVU (TP Orthodontics, La Porte, Ind), and Inspire Ice (Ormco, Glendora, Calif)-were tested to compare and quantitatively analyze differences in the surface features of each ceramic bracket base using scanning electron microscopy (SEM), a three-dimensional (3D) optical surface profiler, and microcomputed tomography (micro-CT). One-way analysis of variance was used to find differences in bracket base surface roughness values and surface areas between groups according to base designs. Tukey's honestly significant differences tests were used for post hoc comparisons. SEM revealed that each bracket exhibited a unique surface texture (MicroArch, double mesh; Crystaline MB, irregular; INVU, single mesh; Inspire Ice, bead ball). With a 3D optical surface profiler, the stainless steel bracket showed significantly higher surface roughness values. Crystaline MB had significantly higher surface roughness values than Inspire Ice. Micro-CT demonstrated that stainless steel brackets showed significantly higher whole and unit bracket base surface areas. Among ceramic brackets, INVU showed significantly higher whole bracket base surface area, and Crystaline MB showed a significantly higher unit bracket base surface area than Inspire Ice. Irregular bracket surface features showed the highest surface roughness values and unit bracket base surface area among ceramic brackets, which contributes to increased mechanically retentive bracket bonding strength.
A Transcription System from MusicXML Format to Braille Music Notation
NASA Astrophysics Data System (ADS)
Goto, D.; Gotoh, T.; Minamikawa-Tachino, R.; Tamura, N.
2006-12-01
The Internet enables us to freely access music as recorded sound and even music scores. For the visually impaired, music scores must be transcribed from computer-based musical formats to Braille music notation. This paper proposes a transcription system from the MusicXML format to Braille music notation using a structural model of Braille music notation. The resultant Braille scores inspected by volunteer transcribers are up to the international standard. Using this simple and efficient transcription system, it should be possible to provide Braille music scores via the Internet to the visually impaired.
Lexicographic Probability, Conditional Probability, and Nonstandard Probability
2009-11-11
the following conditions: CP1. µ(U |U) = 1 if U ∈ F ′. CP2 . µ(V1 ∪ V2 |U) = µ(V1 |U) + µ(V2 |U) if V1 ∩ V2 = ∅, U ∈ F ′, and V1, V2 ∈ F . CP3. µ(V |U...µ(V |X)× µ(X |U) if V ⊆ X ⊆ U , U,X ∈ F ′, V ∈ F . Note that it follows from CP1 and CP2 that µ(· |U) is a probability measure on (W,F) (and, in... CP2 hold. This is easily seen to determine µ. Moreover, µ vaciously satisfies CP3, since there do not exist distinct sets U and X in F ′ such that U
Microleakage under orthodontic brackets bonded with different adhesive systems.
Alkis, Huseyin; Turkkahraman, Hakan; Adanir, Necdet
2015-01-01
This in vitro study aimed to compare the microleakage of orthodontic brackets between enamel-adhesive and adhesive-bracket interfaces at the occlusal and gingival margins bonded with different adhesive systems. A total of 144 human maxillary premolar teeth extracted for orthodontic reasons was randomly divided into four groups. Each group was then further divided into three sub-groups. Three total-etching bonding systems (Transbond XT, Greengloo and Kurasper F), three one-step self-etching bonding systems (Transbond Plus SEP, Bond Force and Clearfil S3), three two-step self-etching bonding systems (Clearfil SE Bond, Clearfil Protectbond and Clearfil Liner Bond), and three self-adhesive resin cements (Maxcem Elite, Relyx U 100 and Clearfil SA Cement) were used to bond the brackets to the teeth. After bonding, all teeth were sealed with nail varnish and stained with 0.5% basic fuchsine for 24 h. All samples were sectioned and examined under a stereomicroscope to score for microleakage at the adhesive-enamel and adhesive-bracket interfaces from both occlusal and gingival margins. Statistical analyses were performed with Kruskal-Wallis and Wilcoxon signed-rank tests. The results indicate no statistically significant differences between the microleakage scores of the adhesives; microleakage was detected in all groups. Comparison of the average values of the microleakage scores in the enamel-adhesive and adhesive-bracket interfaces indicated statistically significant differences (P < 0.05). The amount of the microleakage was higher at the enamel-adhesive interface than at the bracket-adhesive interface. All of the brackets exhibited some amount of microleakage. This result means that microleakage does not depend on the type of adhesive used.
Microleakage under orthodontic brackets bonded with different adhesive systems
Alkis, Huseyin; Turkkahraman, Hakan; Adanir, Necdet
2015-01-01
Objective: This in vitro study aimed to compare the microleakage of orthodontic brackets between enamel-adhesive and adhesive-bracket interfaces at the occlusal and gingival margins bonded with different adhesive systems. Materials and Methods: A total of 144 human maxillary premolar teeth extracted for orthodontic reasons was randomly divided into four groups. Each group was then further divided into three sub-groups. Three total-etching bonding systems (Transbond XT, Greengloo and Kurasper F), three one-step self-etching bonding systems (Transbond Plus SEP, Bond Force and Clearfil S3), three two-step self-etching bonding systems (Clearfil SE Bond, Clearfil Protectbond and Clearfil Liner Bond), and three self-adhesive resin cements (Maxcem Elite, Relyx U 100 and Clearfil SA Cement) were used to bond the brackets to the teeth. After bonding, all teeth were sealed with nail varnish and stained with 0.5% basic fuchsine for 24 h. All samples were sectioned and examined under a stereomicroscope to score for microleakage at the adhesive–enamel and adhesive–bracket interfaces from both occlusal and gingival margins. Statistical Analysis Used: Statistical analyses were performed with Kruskal–Wallis and Wilcoxon signed-rank tests. Results: The results indicate no statistically significant differences between the microleakage scores of the adhesives; microleakage was detected in all groups. Comparison of the average values of the microleakage scores in the enamel–adhesive and adhesive–bracket interfaces indicated statistically significant differences (P < 0.05). The amount of the microleakage was higher at the enamel–adhesive interface than at the bracket-adhesive interface. Conclusions: All of the brackets exhibited some amount of microleakage. This result means that microleakage does not depend on the type of adhesive used. PMID:25713494
The influence of electron beam irradiation on colour stability and hardness of aesthetic brackets.
Faltermeier, Julia; Simon, Philipp; Reicheneder, Claudia; Proff, Peter; Faltermeier, Andreas
2012-08-01
Electron beam irradiation can be used to improve the mechanical properties of polymers. The aim of this study was to investigate the influence of electron beam irradiation with an energy dose of 100 kGy on the mechanical properties and colour stability of conventional polymer brackets and experimental filled composite brackets. The conventional brackets tested were Aesthetik-Line, Brillant, and Envision. The experimental brackets contained urethane dimethacrylate, as a monomer matrix and functional silane-treated SiO(2) fillers with a filler content of either 10 (Exper 1) or 40 (Exper 2) vol per cent. The influence of electron beam post-curing on Vickers hardness (VH) of the polymer brackets was investigated. Additionally, a possible discolouration of the brackets after electron beam irradiation was determined according to the three-dimensional L* a* b* colour space. The irradiated brackets were compared with untreated control groups. Statistical analysis was performed using the Wilcoxon test. With the exception of Brillant brackets, all investigated brackets showed a significant enhancement of VH after electron beam post-curing. However, the brackets suffered a significant increase in discolouration. Aesthetik-Line brackets showed the highest discolouration, ΔE, and Exper 2 brackets the lowest ΔE values. The discolouration of the examined brackets differed significantly. These results demonstrate that the mechanical properties of polymer brackets could be modified by electron beam irradiation. Nevertheless, clinical use of electron beam post-curing might be restricted because of unacceptable colour changes.
NASA Astrophysics Data System (ADS)
Deming, Grace; Hayes-Gehrke, M.; Hamilton, D.
2008-05-01
The Astronomy Workshop (http://janus.astro.umd.edu) is a collection of interactive World Wide Web tools that were developed under the direction of Doug Hamilton for use in undergraduate classes and by the general public. The philosophy of the site is to foster student interest in astronomy by exploiting their fascination with computers and the internet. We have upgraded the "Scientific Notation" tool in response to faculty feedback and input from student interviews. In addition to providing students practice in changing decimal numbers into scientific notation, they may now practice multiplication and division with numbers in scientific notation. We have added instructor materials and student quizzes to enhance the instructional use of the scientific notation web tools. This research was sponsored by NASA EPO grant NNG06GGF99G.
30 CFR 75.1202-1 - Temporary notations, revisions, and supplements.
Code of Federal Regulations, 2012 CFR
2012-07-01
... LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Maps § 75.1202-1 Temporary notations, revisions, and supplements. (a) Mine maps shall be revised and supplemented at...
30 CFR 75.1202-1 - Temporary notations, revisions, and supplements.
Code of Federal Regulations, 2011 CFR
2011-07-01
... LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Maps § 75.1202-1 Temporary notations, revisions, and supplements. (a) Mine maps shall be revised and supplemented at...
30 CFR 75.1202-1 - Temporary notations, revisions, and supplements.
Code of Federal Regulations, 2010 CFR
2010-07-01
... LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Maps § 75.1202-1 Temporary notations, revisions, and supplements. (a) Mine maps shall be revised and supplemented at...
30 CFR 75.1202-1 - Temporary notations, revisions, and supplements.
Code of Federal Regulations, 2014 CFR
2014-07-01
... LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Maps § 75.1202-1 Temporary notations, revisions, and supplements. (a) Mine maps shall be revised and supplemented at...
30 CFR 75.1202-1 - Temporary notations, revisions, and supplements.
Code of Federal Regulations, 2013 CFR
2013-07-01
... LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Maps § 75.1202-1 Temporary notations, revisions, and supplements. (a) Mine maps shall be revised and supplemented at...
NASA Technical Reports Server (NTRS)
Caves, C. M.; Schumaker, B. L.
1985-01-01
A new formalism for analyzing two-photon devices, such as parametric amplifiers and phase-conjugate mirrors, is proposed in part I, focusing on the properties and the significance of the quadrature-phase amplitudes and two-mode squeezed states. Time-stationary quasi-probability noise is also detailed for the case of Gaussian noise, and uncertainty principles for the quadrature-phase amplitudes are outlined, as well as some important properties of the two-mode states. Part II establishes a mathematical foundation for the formalism, with introduction of a vector notation for compact representation of two-mode properties. Fundamental unitary operators and special quantum states are also examined with an emphasis on the two-mode squeezed states. The results are applied to a previously studied degenerate limit (epsilon = 0).
NASA Technical Reports Server (NTRS)
Caves, C. M.; Schumaker, B. L.
1985-01-01
A new formalism for analyzing two-photon devices, such as parametric amplifiers and phase-conjugate mirrors, is proposed in part I, focusing on the properties and the significance of the quadrature-phase amplitudes and two-mode squeezed states. Time-stationary quasi-probability noise is also detailed for the case of Gaussian noise, and uncertainty principles for the quadrature-phase amplitudes are outlined, as well as some important properties of the two-mode states. Part II establishes a mathematical foundation for the formalism, with introduction of a vector notation for compact representation of two-mode properties. Fundamental unitary operators and special quantum states are also examined with an emphasis on the two-mode squeezed states. The results are applied to a previously studied degenerate limit (epsilon = 0).
On covariant Poisson brackets in classical field theory
NASA Astrophysics Data System (ADS)
Forger, Michael; Salles, Mário O.
2015-10-01
How to give a natural geometric definition of a covariant Poisson bracket in classical field theory has for a long time been an open problem—as testified by the extensive literature on "multisymplectic Poisson brackets," together with the fact that all these proposals suffer from serious defects. On the other hand, the functional approach does provide a good candidate which has come to be known as the Peierls-De Witt bracket and whose construction in a geometrical setting is now well understood. Here, we show how the basic "multisymplectic Poisson bracket" already proposed in the 1970s can be derived from the Peierls-De Witt bracket, applied to a special class of functionals. This relation allows to trace back most (if not all) of the problems encountered in the past to ambiguities (the relation between differential forms on multiphase space and the functionals they define is not one-to-one) and also to the fact that this class of functionals does not form a Poisson subalgebra.
Symbolic, Nonsymbolic and Conceptual: An Across-Notation Study on the Space Mapping of Numerals.
Zhang, Yu; You, Xuqun; Zhu, Rongjuan
2016-07-01
Previous studies suggested that there are interconnections between two numeral modalities of symbolic notation and nonsymbolic notation (array of dots), differences and similarities of the processing, and representation of the two modalities have both been found in previous research. However, whether there are differences between the spatial representation and numeral-space mapping of the two numeral modalities of symbolic notation and nonsymbolic notation is still uninvestigated. The present study aims to examine whether there are differences between the spatial representation and numeral-space mapping of the two numeral modalities of symbolic notation and nonsymbolic notation; especially how zero, as both a symbolic magnitude numeral and a nonsymbolic conceptual numeral, mapping onto space; and if the mapping happens automatically at an early stage of the numeral information processing. Results of the two experiments demonstrate that the low-level processing of symbolic numerals including zero and nonsymbolic numerals except zero can mapping onto space, whereas the low-level processing of nonsymbolic zero as a semantic conceptual numeral cannot mapping onto space, which indicating the specialty of zero in the numeral domain. The present study indicates that the processing of non-semantic numerals can mapping onto space, whereas semantic conceptual numerals cannot mapping onto space. © The Author(s) 2016.
The skin notation in the MAC list and classification of dangerous chemicals.
Kupczewska-Dobecka, Małgorzata; Czerczak, Sławomir
2006-01-01
The European Union has published a list of dangerous chemicals, along with classification and labeling; in 1997 the list was adapted to the requirements of Polish regulations and has been continuously updated since then. We have decided to adopt data on dangerous chemicals classification in the list referring to their dermal absorption to assess whether the skin notation is required in the maximum admissible concentration (MAC) list. In Poland, the Group of Experts for Chemical Agents (GECA) decides on assigning the skin absorption notation (symbol Sk) when analyzing the literature data collected in order to prepare occupational exposure limits documentation. The LD50s value serves as the main criterion for assigning the notation. The limit value of 1000 mg/kg has been set as the criterion for applying the skin notation. Documented results of animal and human research, which point to systemic effects resulting from dermal exposure and physicochemical characteristics enabling calculation of the dermal absorption rate may also be used as the basis for assigning the skin notation. Chemicals for which GECA recommended using the skin notation in the 2004 MAC list have been analyzed. It was concluded that information on the classification of chemicals in the list of dangerous chemicals is useful for assessing the skin absorption, but quantitative assessment of absorption rate compared to "safe" levels, using the available theoretical models, should also be attempted.
Confidence Probability versus Detection Probability
Axelrod, M
2005-08-18
In a discovery sampling activity the auditor seeks to vet an inventory by measuring (or inspecting) a random sample of items from the inventory. When the auditor finds every sample item in compliance, he must then make a confidence statement about the whole inventory. For example, the auditor might say: ''We believe that this inventory of 100 items contains no more than 5 defectives with 95% confidence.'' Note this is a retrospective statement in that it asserts something about the inventory after the sample was selected and measured. Contrast this to the prospective statement: ''We will detect the existence of more than 5 defective items in this inventory with 95% probability.'' The former uses confidence probability while the latter uses detection probability. For a given sample size, the two probabilities need not be equal, indeed they could differ significantly. Both these probabilities critically depend on the auditor's prior belief about the number of defectives in the inventory and how he defines non-compliance. In other words, the answer strongly depends on how the question is framed.
Notational analysis of American women's collegiate water polo matches.
Lupo, Corrado; Tessitore, Antonio; Minganti, Carlo; King, Barry; Cortis, Cristina; Capranica, Laura
2011-03-01
Women's water polo is a relatively recent addition to the program of the Olympic Games, making its debut in 2000. Although technical and tactical aspects of men's water polo performance have been studied, there is a paucity of information on the women's competition. Thus, the present study aimed to analyze the technical and tactical aspects of 12 National Collegiate Athletic Association (NCAA) women's water polo matches in relation to 3 playing situations (Even, Counterattack, Power Play) and match outcome (winning and losing teams). The notational analysis included the following indicators: frequency of occurrence of the offensive actions, duration, players, passes, turnovers, exclusion and penalty achievement, goal, and origin and type of shot. Differences between winning and losing teams emerged for duration of actions (p = 0.024), number of players (p = 0.033), passes (p < 0.0001), exclusions and penalties achieved (p = 0.026), shots originating inside (p = 0.002) and outside (p = 0.002) the 5-m area, and occurrence of goals (p < 0.0001) during the Even situation; exclusions and penalties achieved (p = 0.029), shots following up fake (p = 0.049), and goals (p = 0.021) during the Counterattacks; and passes (p = 0.02), and goals (p = 0.003) during the Power-Play actions. In conclusion, winners showed a better ability to perform faster actions, with more effective passes leading to goals. Thus, women's water polo NCAA coaches and conditioners are encouraged to evaluate the studied technical and tactical parameters when analyzing game performances of their teams.
Bonded Bracket Assmebly for Frameless Solar Panels
Murray, Todd; Jackson, Nick; Dupont, Luc; Moser, Jeff
2013-01-30
In February 2011 the US Department of Energy announced their new Sunshot Initiative. The Sunshot goal is to reduce the total cost of solar energy systems by about 75 percent before the end of the decade. The DOE estimated that a total installed cost of $$1 per watt for photovoltaic systems would be equivalent to 5-6¢/kilowatt hour (kWh) for energy available from the grid. The DOE also estimated that to meet the $1 per watt goal, PV module costs would need to be reduced to $ .50 per watt, balance of systems costs would need to be reduced to $.40 per watt, and power electronic costs would need to reach $.10 per watt. To address the BOS balance of systems cost component of the $1 per watt goal, the DOE announced a funding opportunity called (BOS-X) Extreme Balance of System Hardware Cost Reductions. The DOE identified eight areas within the total BOS costs: 1) installation labor, 2) installation materials, 3) installation overhead and profit, 4) tracker, 5) permitting and commissioning, 6) site preparation, 7) land acquisition, 8) sales tax. The BOS-X funding announcement requested applications in four specific topics;Topic 1: Transformational Building Integrated Photovoltaic (BIPV) Modules; Topic 2: Roof and Ground Mount Innovations; Topic 3: Transformational Photovoltaic System Designs; and Topic 4: Development of New Wind Load Codes for PV Systems.The application submitted by ARaymond Tinnerman reflected the requirements listed in Topic #2, Roof and Ground Mount Innovations. The goal of topic #2 was to develop technologies that would result in the extreme reduction of material and labor costs associated with applications that require physical connections and attachments to roof and ground mount structures. The topics researched in this project included component cost reduction, labor reduction, weight reduction, wiring innovations, and alternative material utilization. The project objectives included; 1) The development of an innovative quick snap bracket assembly
Second order root control of self-ligating brackets and traditional brackets: a "typodont" study.
Butti, A C; Mangiacapra, R; Saporito, I; Augusti, G; Salvato, A; Re, D
2014-03-01
Aim of the study was to evaluate if self-ligating brackets (SLB) and conventional brackets (CB) have the same degree of second order root control in closing extraction spaces. Two resin models, left and right sides of an upper arch, with two wells in the premolar area, were used. Wells have been filled with wax and resin premolars with anatomic root structure were placed in them. Resin premolars were bonded with CB and SLB. We performed 20 pairwise runs: CB on one side against SLB on the other side. We tested 0.018 and 0.016x0.022 stainless steel arches. Models were put in warm water to allow teeth to move in the softened wax by the force excerpted by NiTi coils. Root control in the second order was evaluated with the aid of metallic markers on the roots and digital radiographies taken before and after each run. On 0.018 wires CB moved 4.0 mm (SD 1.06 mm), mean root control angle was 14.8° (SD 9.15°), while SLB moved 4.1 mm (SD 1.33 mm), mean angle in the second order was 11.8° (SD 5.01°). On 0.016x0.022 wires CB moved 3.6 mm (SD 1.24 mm), mean angle in the second order was 9.7° (SD 5.48°) while SLB moved 3.4 mm (SD 1.05 mm), mean angle was 10.7° (SD 3.92°). It seems that, on typodont, CB and SLB are equally efficient in moving teeth crowns and have the same degree of second order root control, both when 0.018 and 0.016x0.022 stainless steel wires are used.
Study of force loss due to friction comparing two ceramic brackets during sliding tooth movement.
AlSubaie, Mai; Talic, Nabeel; Khawatmi, Said; Alobeid, Ahmad; Bourauel, Christoph; El-Bialy, Tarek
2016-09-01
To compare the percentage of force loss generated during canine sliding movements in newly introduced ceramic brackets with metal brackets. Two types of ceramic brackets, namely polycrystalline alumina (PCA) ceramic brackets (Clarity Advanced) and monocrystalline alumina (MCA) ceramic brackets (Inspire Ice) were compared with stainless steel (SS) brackets (Victory Series). All bracket groups (n = 5 each) were for the maxillary canines and had a 0.018-inch slot size. The brackets were mounted on an Orthodontic Measurement and Simulation System (OMSS) to simulate the canine retraction movement into the first premolar extraction space. Using elastic ligatures, 0.016 × 0.022″ (0.40 × 0.56 mm) stainless steel archwires were ligated onto the brackets. Retraction force was applied via a nickel-titanium coil spring with a nearly constant force of approximately 1 N. The OMSS measured the percentage of force loss over the retraction path by referring to the difference between the applied retraction force and actual force acting on each bracket. Between group comparisons were done with one-way analysis of variance. The metal brackets revealed the lowest percentage of force loss due to friction, followed by the PCA and MCA ceramic bracket groups (67 ± 4, 68 ± 7, and 76 ± 3 %, respectively). There was no significant difference between SS and PCA brackets (p = 0.97), but we did observe significant differences between metal and MCA brackets (p = 0.03) and between PCA and MCA ceramic brackets (p = 0.04). PCA ceramic brackets, whose slot surface is covered with an yttria-stabilized zirconia-based coating exhibited frictional properties similar to those of metal brackets. Frictional resistance resulted in an over 60 % loss of the applied force due to the use of elastic ligatures.
Design of an Orthodontic Torque Simulator for Measurement of Bracket Deformation
NASA Astrophysics Data System (ADS)
Melenka, G. W.; Nobes, D. S.; Major, P. W.; Carey, J. P.
2013-12-01
The design and testing of an orthodontic torque simulator that reproduces the effect of archwire rotation on orthodontic brackets is described. This unique device is capable of simultaneously measuring the deformation and loads applied to an orthodontic bracket due to archwire rotation. Archwire rotation is used by orthodontists to correct the inclination of teeth within the mouth. This orthodontic torque simulator will provide knowledge of the deformation and loads applied to orthodontic bracket that will aide clinicians by describing the effect of archwire rotation on brackets. This will also impact that design on new archwirebracket systems by providing an assessment of performance. Deformation of the orthodontic bracket tie wings is measured using a digital image correlation process to measure elastic and plastic deformation. The magnitude of force and moments applied to the bracket though the archwire is also measured using a six-axis load cell. Initial tests have been performed on two orthodontic brackets of varying geometry to demonstrate the measurement capability of the orthodontic torque simulator. The demonstration experiment shows that a Damon Q bracket had a final plastic deformation after a single loading of 0.022 mm while the Speed bracket deformed 0.071 mm. This indicates that the Speed bracket plastically deforms 3.2 times more than the Damon Q bracket for similar magnitude of applied moment. The demonstration experiment demonstrates that bracket geometry affect the deformation of orthodontic brackets and this difference can be detected using the orthodontic torque simulator.
Air-powder polishing on self-ligating brackets after clinical use: effects on debris levels
Aragón, Mônica L. S. Castro; Lima, Leandro Santiago; Normando, David
2016-01-01
ABSTRACT Introduction: Debris buildup on brackets and arch surfaces is one of the main factors that can influence the intensity of friction between bracket and orthodontic wire. Objective: This study sought to evaluate the effect of air-powder polishing cleaning on debris levels of self-ligating ceramic brackets at the end of orthodontic treatment, compared to the behavior of conventional brackets. Methods: Debris levels were evaluated in metal conventional orthodontic brackets (n = 42) and ceramic self-ligating brackets (n = 42) on canines and premolars, arranged in pairs. There were brackets with and without air-powder polishing. At the end of orthodontic treatment, a hemiarch served as control and the contralateral hemiarch underwent prophylaxis with air-powder polishing. Debris buildup in bracket slots was assessed through images, and Wilcoxon test was used to analyze the results. Results: The median debris levels were statistically lower in the conventional metal brackets compared to self-ligating ones (p = 0.02), regarding brackets not submitted to air-powder polishing. Polishing significantly reduced debris buildup to zero in both systems, without differences between groups. Conclusions: Ceramic self-ligating brackets have a higher debris buildup in comparison to conventional metal brackets in vivo, but prophylaxis with sodium bicarbonate jet was effective in reducing debris levels in self-ligating and also in conventional brackets. PMID:27901234
Basics of Ternary Algebras and their underlying Nambu Brackets
NASA Astrophysics Data System (ADS)
Zachos, Cosmas K.
2013-12-01
Ternary algebras amount to closing systems of antisymmetrized trinomials of operators. The Filippov conditions (FI, which are not identities) for ternary algebras are contrasted to Bremner's identities dictated by associativity of operator products, and thus analogous to Jacobi identities. Maps of the known FI-compliant ternary algebras to underlying classical Nambu brackets are constructed, which then explain this compliance: FI-compliant ternary algebras are essentially classical Nambu brackets in disguise. In some cases involving infinite algebras, we show the classical limit may be obtained by a contraction of the quantal ternary algebra, and then explicitly realized through classical Nambu brackets. We illustrate this classical-contraction method on our Virasoro-Witt ternary algebra paradigm. The content of the talk is in the two references.
Bracket states for communication protocols with coherent states
NASA Astrophysics Data System (ADS)
Allevi, Alessia; Olivares, Stefano; Bondani, Maria
2014-05-01
We present the generation and characterization of the class of bracket states, namely phase-sensitive mixtures of coherent states exhibiting symmetry properties in the phase-space description. A bracket state can be seen as the statistical ensemble arriving at a receiver in a typical coherent-state-based communication channel. We show that when a bracket state is mixed at a beam splitter with a local oscillator, both the emerging beams exhibit a Fano factor larger than 1 and dependent on the relative phase between the input state and the local oscillator. We discuss the possibility to exploit this dependence to monitor the phase difference for the enhancement of the performances of a simple communication scheme based on direct detection. Our experimental setup involves linear optical elements and a pair of photon-number-resolving detectors operated in the mesoscopic photon-number domain.
Bering's proposal for boundary contribution to the Poisson bracket
NASA Astrophysics Data System (ADS)
Soloviev, Vladimir O.
2000-08-01
It is shown that the Poisson bracket with boundary terms proposed by Bering can be deduced from the Poisson bracket proposed by the present author if one omits terms free of Euler-Lagrange derivatives ("annihilation principle"). This corresponds to another definition of the formal product of distributions (or, saying it in other words, to another definition of the pairing between 1-forms and 1-vectors in the formal variational calculus). We extend the formula (initially suggested by Bering for the ultralocal case with constant coefficients only) onto the general nonultralocal brackets with coefficients depending on fields and their spatial derivatives. The lack of invariance under changes of dependent variables (field redefinitions) seems to be a drawback of this proposal.
Wiemuth, M; Junger, D; Leitritz, M A; Neumann, J; Neumuth, T; Burgert, O
2017-08-01
Medical processes can be modeled using different methods and notations. Currently used modeling systems like Business Process Model and Notation (BPMN) are not capable of describing the highly flexible and variable medical processes in sufficient detail. We combined two modeling systems, Business Process Management (BPM) and Adaptive Case Management (ACM), to be able to model non-deterministic medical processes. We used the new Standards Case Management Model and Notation (CMMN) and Decision Management Notation (DMN). First, we explain how CMMN, DMN and BPMN could be used to model non-deterministic medical processes. We applied this methodology to model 79 cataract operations provided by University Hospital Leipzig, Germany, and four cataract operations provided by University Eye Hospital Tuebingen, Germany. Our model consists of 85 tasks and about 20 decisions in BPMN. We were able to expand the system with more complex situations that might appear during an intervention. An effective modeling of the cataract intervention is possible using the combination of BPM and ACM. The combination gives the possibility to depict complex processes with complex decisions. This combination allows a significant advantage for modeling perioperative processes.
Structural Analysis of the Redesigned Ice/Frost Ramp Bracket
NASA Technical Reports Server (NTRS)
Phillips, D. R.; Dawicke, D. S.; Gentz, S. J.; Roberts, P. W.; Raju, I. S.
2007-01-01
This paper describes the interim structural analysis of a redesigned Ice/Frost Ramp bracket for the Space Shuttle External Tank (ET). The proposed redesigned bracket consists of mounts for attachment to the ET wall, supports for the electronic/instrument cables and propellant repressurization lines that run along the ET, an upper plate, a lower plate, and complex bolted connections. The eight nominal bolted connections are considered critical in the summarized structural analysis. Each bolted connection contains a bolt, a nut, four washers, and a non-metallic spacer and block that are designed for thermal insulation. A three-dimensional (3D) finite element model of the bracket is developed using solid 10-node tetrahedral elements. The loading provided by the ET Project is used in the analysis. Because of the complexities associated with accurately modeling the bolted connections in the bracket, the analysis is performed using a global/local analysis procedure. The finite element analysis of the bracket identifies one of the eight bolted connections as having high stress concentrations. A local area of the bracket surrounding this bolted connection is extracted from the global model and used as a local model. Within the local model, the various components of the bolted connection are refined, and contact is introduced along the appropriate interfaces determined by the analysts. The deformations from the global model are applied as boundary conditions to the local model. The results from the global/local analysis show that while the stresses in the bolts are well within yield, the spacers fail due to compression. The primary objective of the interim structural analysis is to show concept viability for static thermal testing. The proposed design concept would undergo continued design optimization to address the identified analytical assumptions and concept shortcomings, assuming successful thermal testing.
In vitro comparison of the retention capacity of new aesthetic brackets.
Fernandez, L; Canut, J A
1999-02-01
Tensile bond strength and bond failure location were evaluated in vitro for two types of aesthetic brackets (non-silanated ceramic, polycarbonate) and one stainless steel bracket, using bovine teeth as the substrate and diacrylate resin as the adhesive. The results show that metallic bracket had the highest bond strength (13.21 N) followed by the new plastic bracket (12.01 N), which does not require the use of a primer. The non-silanated ceramic bracket produced the lowest bond strength (8.88 N). Bond failures occurred mainly between bracket and cement, although a small percentage occurred between the enamel-cement interface with the metal and plastic brackets and within the cement for the plastic bracket. With the ceramic bracket all the failures occurred at the bracket-cement interface. This suggests that the problems of enamel lesions produced by this type of bracket may have been eliminated. The results also show that the enamel/adhesive bond is stronger than the adhesive/bracket bond in this in vitro study.
In vitro oxidative stress induced by conventional and self-ligating brackets.
Buljan, Zorana Ivankovic; Ribaric, Sonja Pezelj; Abram, Maja; Ivankovic, Ante; Spalj, Stjepan
2012-03-01
To determine the in vitro oxidative stress induced by conventional and self-ligating brackets made of different materials. The concentration of oxidative stress marker 8-hydroxy-2'-deoxyguanosine (8-OHdG) in DNA of murine fibroblast cells L929 after in vitro exposure to three types of conventional and four types of self-ligating brackets was assessed. To determine viability and changes in the number of cells before and after exposure, trypan blue dye was used. Analysis of variance (ANOVA) was used for statistical analysis. No significant difference in cell viability was noted between metal, ceramic, and polymeric conventional brackets, and self-ligating brackets made of combinations of those materials, but viability was significantly higher compared with positive controls (P < .05). The conventional sapphire ceramic bracket (Inspire Ice) showed high viability, the largest increase in the number of cells, and the lowest oxidative stress. A higher concentration of markers of oxidative stress was observed in full metal conventional and self-ligating brackets (MiniSprint and Speed) and in conventional polyurethane brackets (Quantum) compared with negative controls (P < .05). All types of orthodontic brackets, regardless of the constituent materials, are a source of oxidative stress in vitro, but the highest stress was induced in the full metal and polyurethane brackets. Conventional ceramic brackets show the highest degree of biocompatibility compared with polymeric and metal brackets and self-ligating brackets made from combinations of these materials.
43. Detail view of pivoting bracket used to move heavy ...
43. Detail view of pivoting bracket used to move heavy iron plate that covered trough next to iron notch when No. 2 Furnace was tapped. - Sloss-Sheffield Steel & Iron, First Avenue North Viaduct at Thirty-second Street, Birmingham, Jefferson County, AL
Interior, view of central hall staircase showing bracketed stair, square ...
Interior, view of central hall staircase showing bracketed stair, square balusters and fluted newel post, camera facing southwest - Naval Training Station, Senior Officers' Quarters District, Quarters No. 4, Naval Station Treasure Island, 4 Whiting Way, Yerba Buena Island, San Francisco, San Francisco County, CA
Evaluation of bond strength of orthodontic brackets without enamel etching
Boruziniat, Alireza; Motaghi, Shiva; Moghaddas, Mohmmadjavad
2015-01-01
Background To compare the shear bond strength of brackets with and without enamel etching. Material and Methods In this study, 60 sound premolars were randomly divided into four different groups: 1- TXE group: Enamel etching+Transbond XT adhesive+ Transbond XT composite. 2- TXS group: Transbond plus self-etch adhesive+ Transbond XT composite. 3- PQ1E group: Enamel etching+ PQ1 adhesive+ Transbond XT composite. 4- PQ1 group: PQ1 adhesive+ Transbond XT composite. The shear bond strengths of brackets were evaluated using universal testing machine at cross head speed of 0.5 mm/min. The Adhesive Remnant Index (ARI) was also measured. One-way ANOVA, Tukey’s post hoc, Kruskal-wallis and Mann-Witney U test were used for data analysis. Results There was a significant difference between etched and unetched groups respect to SBS and ARI (p<0.05), however; no significant difference was observed between unetched group and self-etch adhesive group (p>> 0.05). The shear bond strength of PQ1 group was the least but in acceptable range and its ARI was less than other groups. Conclusions PQ1 adhesive can be used for bracket bonding without enamel etching with adequate bond strength and minimal ARI. Key words:Bracket, shear bond strength, filled-adhesive, self-etch adhesive. PMID:26535100
The Moyal bracket in the coherent states framework
NASA Astrophysics Data System (ADS)
Daoud, M.; El Kinani, E. H.
2002-03-01
The star product and Moyal bracket are introduced using the coherent states corresponding to quantum systems with non-linear spectra. Two kinds of coherent state are considered. The first kind is the set of Gazeau-Klauder coherent states and the second kind are constructed following the Perelomov-Klauder approach. The particular case of the harmonic oscillator is also discussed.
The Schouten - Nijenhuis bracket, cohomology and generalized Poisson structures
NASA Astrophysics Data System (ADS)
de Azcárraga, J. A.; Perelomov, A. M.; Pérez Bueno, J. C.
1996-12-01
Newly introduced generalized Poisson structures based on suitable skew-symmetric contravariant tensors of even order are discussed in terms of the Schouten - Nijenhuis bracket. The associated `Jacobi identities' are expressed as conditions on these tensors, the cohomological contents of which is given. In particular, we determine the linear generalized Poisson structures which can be constructed on the dual spaces of simple Lie algebras.
Investigations in a Simplified Bracketed Grid Approach to Metrical Structure
ERIC Educational Resources Information Center
Liu, Patrick Pei
2010-01-01
In this dissertation, I examine the fundamental mechanisms and assumptions of the Simplified Bracketed Grid Theory (Idsardi 1992) in two ways: first, by comparing it with Parametric Metrical Theory (Hayes 1995), and second, by implementing it in the analysis of several case studies in stress assignment and syllabification. Throughout these…
Poisson cohomology of scalar multidimensional Dubrovin-Novikov brackets
NASA Astrophysics Data System (ADS)
Carlet, Guido; Casati, Matteo; Shadrin, Sergey
2017-04-01
We compute the Poisson cohomology of a scalar Poisson bracket of Dubrovin-Novikov type with D independent variables. We find that the second and third cohomology groups are generically non-vanishing in D > 1. Hence, in contrast with the D = 1 case, the deformation theory in the multivariable case is non-trivial.
On covariant Poisson brackets in classical field theory
Forger, Michael; Salles, Mário O.
2015-10-15
How to give a natural geometric definition of a covariant Poisson bracket in classical field theory has for a long time been an open problem—as testified by the extensive literature on “multisymplectic Poisson brackets,” together with the fact that all these proposals suffer from serious defects. On the other hand, the functional approach does provide a good candidate which has come to be known as the Peierls–De Witt bracket and whose construction in a geometrical setting is now well understood. Here, we show how the basic “multisymplectic Poisson bracket” already proposed in the 1970s can be derived from the Peierls–De Witt bracket, applied to a special class of functionals. This relation allows to trace back most (if not all) of the problems encountered in the past to ambiguities (the relation between differential forms on multiphase space and the functionals they define is not one-to-one) and also to the fact that this class of functionals does not form a Poisson subalgebra.
Use of an adhesive resin for bonding orthodontic brackets.
Ireland, A J; Sherriff, M
1994-02-01
To date, most successful bonding agents used in orthodontics rely on mechanical retention to both the enamel and bracket base. Chemical adhesion to enamel as seen with glass ionomer cements, and to the silanated base of ceramic brackets have been tried. Recent developments in resin formulation have led to the production of adhesive diacrylate resins capable of forming adhesive bonds to certain metals including stainless steel. The aim of this experiment was to compare such a resin, Panavia EX, with a more conventional 'no-mix' orthodontic bonding resin. Two different base retention mechanisms were used, and the effect of rebonding and differing environmental conditions were also investigated. The results indicated that Panavia EX could produce greater bond strengths than the more conventional bonding resin. Of the two base retention systems tested, braised mesh bases gave consistently greater bond strengths than the cast base, although no base/resin specificity could be detected. Re-using the same brackets showed rebound strengths to be significantly lower than initial bond strength although the results indicated the adhesive resin was still able to bond more effectively to these used brackets than the conventional resin. Environment had the greatest effect on bond strength, such that following environmental exposure there was no significant difference between the two resins. This latter factor, and in particular the more complex bonding technique required for the adhesive resin, means that Panavia EX cannot be recommended for orthodontic use in its present form.
Investigations in a Simplified Bracketed Grid Approach to Metrical Structure
ERIC Educational Resources Information Center
Liu, Patrick Pei
2010-01-01
In this dissertation, I examine the fundamental mechanisms and assumptions of the Simplified Bracketed Grid Theory (Idsardi 1992) in two ways: first, by comparing it with Parametric Metrical Theory (Hayes 1995), and second, by implementing it in the analysis of several case studies in stress assignment and syllabification. Throughout these…
Yagahara, Ayako; Tsuji, Shintaro; Hukuda, Akihisa; Nishimoto, Naoki; Ogasawara, Katsuhiko
2016-03-01
The purpose of this study is to investigate the differences in the notation of technical terms and their meanings among three terminologies in Japanese radiology-related societies. The three terminologies compared in this study were "radiological technology terminology" and its supplement published by the Japan Society of Radiological Technology, "medical physics terminology" published by the Japan Society of Medical Physics, and "electric radiation terminology" published by the Japan Radiological Society. Terms were entered into spreadsheets and classified into the following three categories: Japanese notation, English notation, and meanings. In the English notation, terms were matched to character strings in the three terminologies and were extracted and compared. The Japanese notations were compared among three terminologies, and the difference between the meanings of the two terminologies radiological technology terminology and electric radiation terminology were compared. There were a total of 14,982 terms in the three terminologies. In English character strings, 2,735 terms were matched to more than two terminologies, with 801 of these terms matched to all the three terminologies. Of those terms in English character strings matched to three terminologies, 752 matched to Japanese character strings. Of the terms in English character strings matched to two terminologies, 1,240 matched to Japanese character strings. With regard to the meanings category, eight terms had mismatched meanings between the two terminologies. For these terms, there were common concepts between two different meaning terms, and it was considered that the derived concepts were described based on domain.
Friction behavior of ceramic injection-molded (CIM) brackets.
Reimann, Susanne; Bourauel, Christoph; Weber, Anna; Dirk, Cornelius; Lietz, Thomas
2016-07-01
Bracket material, bracket design, archwire material, and ligature type are critical modifiers of friction behavior during archwire-guided movement of teeth. We designed this in vitro study to compare the friction losses of ceramic injection-molded (CIM) versus pressed-ceramic (PC) and metal injection-molded (MIM) brackets-used with different ligatures and archwires-during archwire-guided retraction of a canine. Nine bracket systems were compared, including five CIM (Clarity™ and Clarity™ ADVANCED, both by 3M Unitek; discovery(®) pearl by Dentaurum; Glam by Forestadent; InVu by TP Orthodontics), two PC (Inspire Ice by Ormco; Mystique by DENTSPLY GAC), and two MIM (discovery(®) and discovery(®) smart, both by Dentaurum) systems. All of these were combined with archwires made of either stainless steel or fiberglass-reinforced resin (remanium(®) ideal arch or Translucent pearl ideal arch, both by Dentaurum) and with elastic ligatures or uncoated or coated stainless steel (all by Dentaurum). Archwire-guided retraction of a canine was simulated with a force of 0.5 N in the orthodontic measurement and simulation system (OMSS). Friction loss was determined by subtracting the effective orthodontic forces from the applied forces. Based on five repeated measurements performed on five brackets each, weighted means were calculated and evaluated by analysis of variance and a Bonferroni post hoc test with a significance level of 0.05. Friction losses were significantly (p < 0.05) higher (58-79 versus 20-30 %) for the combinations involving the steel versus the resin archwire in conjunction with the elastic ligature. The uncoated steel ligatures were associated with the lowest friction losses with Clarity™ (13 %) and discovery(®) pearl (16 %) on the resin archwire and the highest friction losses with Clarity™ ADVANCED (53 %) and Mystique (63 %) on the steel archwire. The coated steel ligatures were associated with friction losses similar to the uncoated steel
Microleakage beneath brackets bonded with flowable materials: effect of thermocycling.
Vicente, Ascensión; Ortiz, Antonio J; Bravo, Luis A
2009-08-01
The purpose of this study was to evaluate the effects of thermocycling on microleakage beneath brackets bonded with an orthodontic composite and different flowable materials. Brackets were bonded to 200 bovine incisors divided into five groups: (1) Transbond XT, (2) X-Flow, (3) Dyract-Flow, (4) Admira-Flow, and (5) Beautiful-Flow. Half the teeth in each group were thermocycled. The specimens were dyed with 1 per cent methylene blue for 24 hours to determine the percentage of microleakage into the enamel-adhesive and adhesive-bracket interfaces using image analysis equipment. Data were analysed using the Kruskal-Wallis and Mann-Whitney U-tests (P < 0.05), applying Bonferroni correction when required (P < 0.005). Without thermocycling, microleakage at the enamel-adhesive interface was significantly greater for Admira-Flow than for X-Flow (P < 0.005). At the adhesive-bracket interface, there were no significant differences (P > 0.005). After thermocycling, microleakage of Beautiful-Flow at the enamel-adhesive interface was significantly less than for the other materials tested (P < 0.005), while at the adhesive-bracket interface, Admira-Flow and X-Flow showed significantly more microleakage than Beautiful-Flow and Transbond XT (P < 0.005). Analysis of the effect of thermocycling on each material showed that microleakage increased significantly at the enamel-adhesive interface with Transbond XT (P < 0.05), decreased with Beautiful-Flow (P < 0.05), increased significantly at both interfaces with X-Flow, but not to a statistically significant level with Dyract-Flow and Admira-Flow (P > 0.05). The giomer, Beautiful-Flow, demonstrated the best performance after thermocycling, while composite resins and, in particular, the flowables showed a poorer performance.
A clinical trial of Damon 2 vs conventional twin brackets during initial alignment.
Miles, Peter G; Weyant, Robert J; Rustveld, Luis
2006-05-01
The objective of this study was to compare the effectiveness and comfort of Damon 2 brackets and conventional twin brackets during initial alignment. Sixty consecutive patients participated in a split mouth design. One side of the lower arch was bonded with the Damon 2 bracket and the other with a conventional twin bracket. The sides were alternated with each consecutive patient. The irregularity index (II) was measured for each half of the arch at baseline, at 10 weeks at the first archwire change, and at another 10 weeks at the second archwire change. Any difference in discomfort was assessed within the first few days of archwire placement and again at the first archwire change. Comfort on the lips, preferred look, and bracket failure rates were also recorded. The twin bracket was more uncomfortable with the initial archwire (P = .04). However, at 10 weeks, substantially more patients reported discomfort with the Damon 2 bracket when engaging the archwire (P = .004). At both archwire changes at 10 and 20 weeks (P = .001), the conventional bracket had achieved a lower II than the Damon 2 bracket by 0.2 mm, which is not clinically significant. Patients preferred the look of the twin bracket over the Damon 2 (P < .0005) and more Damon 2 brackets debonded during the study (P < .0005). The Damon 2 bracket was no better during initial alignment than a conventional bracket. Initially, the Damon 2 bracket was less painful, but it was substantially more painful when placing the second archwire and had a higher bracket failure rate.
Sfondrini, Maria Francesca; Fraticelli, Danilo; Daina, Paola; Tamagnone, Alessandra; Gandini, Paola
2013-01-01
Objective. The aim of this study was to compare the shear bond strength (SBS) and adhesive remnant index (ARI) scores of no-primer adhesives tested with two different bracket bases. Materials and Methods. 120 bovine permanent mandibular incisors were divided into 6 groups of 20 specimens. Two brackets (ODP) with different bracket bases (anchor pylons and 80-gauge mesh) were bonded to the teeth using a conventional adhesive (Transbond XT) and two different no-primer adhesive (Ortho Cem; Heliosit) systems. Groups were tested using an instron universal testing machine. SBS values were recorded. ARI scores were measured. SEM microphotographs were taken to evaluate the pattern of bracket bases. Statistical analysis was performed. ANOVA and Tukey tests were carried out for SBS values, whereas a chi-squared test was applied for ARI scores. Results. Highest bond strength values were reported with Transbond XT (with both pad designs), Ortho Cem bonded on anchor pylons and Heliosit on 80-gauge mesh. A higher frequency of ARI score of “3” was reported for Transbond XT groups. Other groups showed a higher frequency of ARI score “2” and “1.” Conclusion. Transbond XT showed the highest shear bond strength values with both pad designs. PMID:23984339
Zhou, Xin; Chu, Baojin; Zhang, Qiming M
2006-08-01
For the polarization response beyond the small field range, Rayleigh's law has been introduced in the past to describe the field-dependent behavior (with loss) of ferroelectric materials with some success. We examine the relationship between Rayleigh's law and the complex dielectric constant notation that has been used widely in the scientific and engineering community; and we show that a modified complex notation can describe the field-dependent dielectric response with loss in the small and medium field range quite well. In addition, the modified complex notation easily can include a field independent dielectric loss that is, in fact, present in all the dielectric materials. The results also show that the alternating current (AC) field response is still predominantly linear with the amplitude and phase of the complex coefficient changing with the applied field amplitude.
Notation of Depression in Case Records of Older Adults in Community Long-Term Care
Proctor, Enola K.
2012-01-01
Although significant numbers of social service clients experience mental health problems, virtually no research has examined the responsiveness of social service agencies to mental disorder. This article examines the extent to which client depression is reflected in records of a public social service agency, community long-term care (CLTC). Researchers assessed new, consenting CLTC clients for depression using standardized research criteria in a telephone interview. Agency case records were abstracted to determine the extent to which client depression was noted. Sensitivity and specificity of depression notation were 25.21 percent and 92.80 percent, respectively, indicating that agency records reflected depression for about one in four clients meeting depression criteria. Factors associated with accurate depression notation included cognitive impairments, low social support, psychotropic medications, and mental health treatment. The depression notation rates found are comparable to those in medical settings. Structured screening and assessment might enhance detection of mental disorder for social service clients. PMID:19275120
Shear bond strength of ceramic brackets with chemical or mechanical retention.
Forsberg, C M; Hagberg, C
1992-08-01
The study was undertaken to measure and compare the shear bond strengths of a ceramic bracket with chemical retention, a ceramic bracket with a new type of textured base providing mechanical retention, and a metal bracket with foil-mesh base. The tests were performed on 51 extracted human premolars which were randomly divided into three equally large groups (n = 17)--one group for each type of bracket. After debonding, the site of failure was noted and the enamel surface inspected with scanning electron microscopy. The ceramic bracket with chemical retention exhibited significantly higher bond strength than the corresponding bracket with textured base. In comparison with the metal bracket significantly higher bond strengths were recorded for both types of ceramic brackets. The ceramic bracket with mechanical retention and the metal bracket were comparable as regards the site of bond failure. In some cases the chemical bond provided very high values of bond strength. Enamel failure were recorded in three teeth which had been bonded with this type of ceramic bracket.
The CNS in the ICU: A Bedside Notation System for Nurses
Mertz, Susan L.; Ash, Stephen R.; Farrell, Joan
1982-01-01
An extended trial of two months was instituted utilizing the CNS as a bedside nursing notation system in an intensive care unit. Analysis of data was based on content analysis of the notes, training time, subjective data and quantitative content of the notes. It is possible to totally replace other written forms of notation in the paper record with a computer printed note. Such a system is well accepted by staff, easy to implement, and results in timely notes of better organization and content without increase in time involved.
Siargos, Barbara; Bradley, Thomas G; Darabara, Myrsini; Papadimitriou, George; Zinelis, Spiros
2007-03-01
To compare the galvanic coupling of conventional and metal injection molded (MIM) brackets with commonly used orthodontic archwires. Six of each type of bracket were suspended in lactic acid along with a sample of orthodontic wire (three nickel-titanium and three copper-nickel-titanium) for 28 days at 37 degrees C. The potential differences between the wires and brackets were recorded per second throughout the duration of the experiment. The MIM brackets exhibited potential differences similar to those seen for the conventional brackets. The greatest potential difference was found for MIM brackets with nickel-titanium wires (512 mV), whereas MIM brackets with copper-nickel-titanium wires had the smallest difference (115 mV). Scanning electron microscope (SEM)-energy-dispersive spectroscopic analysis of the tie-wing area of each bracket type indicated similar elemental composition in both brackets, but in slightly different percentages by weight. The MIM bracket exhibited extensive internal porosity, whereas the conventional bracket was more solid internally. The composition and manufacturing processes involved in fabricating MIM brackets impart corrosive properties similar to those seen in the bracket-wing area of conventional brackets and may provide a measurable benefit when taking into account the increased corrosion between the bracket and brazing alloy of conventional brackets.
Frictional and mechanical properties of diamond-like carbon-coated orthodontic brackets.
Muguruma, Takeshi; Iijima, Masahiro; Brantley, William A; Nakagaki, Susumu; Endo, Kazuhiko; Mizoguchi, Itaru
2013-04-01
This study investigated the effects of a diamond-like carbon (DLC) coating on frictional and mechanical properties of orthodontic brackets. DLC films were deposited on stainless steel brackets using the plasma-based ion implantation/deposition (PBIID) method under two different atmospheric conditions. As-received metal brackets served as the control. Two sizes of stainless steel archwires, 0.018 inch diameter and 0.017 × 0.025 inch cross-section dimensions, were used for measuring static and kinetic friction by drawing the archwires through the bracket slots, using a mechanical testing machine (n = 10). The DLC-coated brackets were observed with a scanning electron microscope (SEM). Values of hardness and elastic modulus were obtained by nanoindentation testing (n = 10). Friction forces were compared by one-way analysis of variance and the Scheffé test. The hardness and elastic modulus of the brackets were compared using Kruskal-Wallis and Mann-Whitney U-tests. SEM photomicrographs showed DLC layers on the bracket surfaces with thickness of approximately 5-7 μm. DLC-coated brackets deposited under condition 2 showed significantly less static frictional force for the stainless steel wire with 0.017 × 0.025 inch cross-section dimensions than as-received brackets and DLC-coated brackets deposited under condition 1, although both DLC-coated brackets showed significantly less kinetic frictional force than as-received brackets. The hardness of the DLC layers was much higher than that of the as-received bracket surfaces. In conclusion, the surfaces of metal brackets can be successfully modified by the PBIID method to create a DLC layer, and the DLC-coating process significantly reduces frictional forces.
ERIC Educational Resources Information Center
Hochgesang, Julie A.
2013-01-01
In my dissertation, I examine four notation systems used to represent hand configurations in child acquisition of signed languages. Linguists have long recognized the descriptive limitations of Stokoe notation, currently the most commonly used system for phonetic or phonological transcription, but continue using it because of its widespread…
ERIC Educational Resources Information Center
Elkoshi, Rivka
2004-01-01
This eight-year study represents a pioneering effort to investigate color expression in children's graphic notations at two stages of development: "Pre-literate" (age: 7.0-8.5), before students received school music instruction, and "Post-literate" (age: 14.0-15.5), three years after students acquired Standard Notation in…
ERIC Educational Resources Information Center
Bentley, Prudence A.
The objective of this paper is to explain the need for and defend the sufficiency of the child's-play method of teaching the place value notation concept to preschool and elementary school children. Discussion first illustrates error patterns of school children in the use and interpretation of place value notation, arguing that the errors reflect…
ERIC Educational Resources Information Center
Hochgesang, Julie A.
2013-01-01
In my dissertation, I examine four notation systems used to represent hand configurations in child acquisition of signed languages. Linguists have long recognized the descriptive limitations of Stokoe notation, currently the most commonly used system for phonetic or phonological transcription, but continue using it because of its widespread…
Fractional Dirac bracket and quantization for constrained systems
NASA Astrophysics Data System (ADS)
Abreu, Everton M. C.; Godinho, Cresus F. L.
2011-08-01
So far, it is not well known how to deal with dissipative systems. There are many paths of investigation in the literature and none of them present a systematic and general procedure to tackle the problem. On the other hand, it is well known that the fractional formalism is a powerful alternative when treating dissipative problems. In this paper, we propose a detailed way of attacking the issue using fractional calculus to construct an extension of the Dirac brackets in order to carry out the quantization of nonconservative theories through the standard canonical way. We believe that, by using the extended Dirac bracket definition, it will be possible to analyze more deeply gauge theories starting with second-class systems.
Femtosecond laser etching of dental enamel for bracket bonding.
Kabas, Ayse Sena; Ersoy, Tansu; Gülsoy, Murat; Akturk, Selcuk
2013-09-01
The aim is to investigate femtosecond laser ablation as an alternative method for enamel etching used before bonding orthodontic brackets. A focused laser beam is scanned over enamel within the area of bonding in a saw tooth pattern with a varying number of lines. After patterning, ceramic brackets are bonded and bonding quality of the proposed technique is measured by a universal testing machine. The results are compared to the conventional acid etching method. Results show that bonding strength is a function of laser average power and the density of the ablated lines. Intrapulpal temperature changes are also recorded and observed minimal effects are observed. Enamel surface of the samples is investigated microscopically and no signs of damage or cracking are observed. In conclusion, femtosecond laser exposure on enamel surface yields controllable patterns that provide efficient bonding strength with less removal of dental tissue than conventional acid-etching technique.
Assessment of computer customized brackets and positioning jigs.
Dewhurst, Robert
2012-01-01
An in-practice assessment of Ormco's CAD CAM Insignia Orthodontic system is reviewed Investigation included an in-vitro and in-vivo analysis of the accuracy of bracket placement, and measurement of the accuracy of slot and torque manufacturing specifications were addressed. The possible role of these systems in general dental practice is discussed. Examination of the Insignia system has led us to believe that changes in the way that orthodontic cases are being planned, treated, and delivered to the patient are changing with the increased use of computer technology. The ability to customize brackets and wires for the individual tooth in the individual patient should lead to better and easier finishing.
In vitro tensile bond strength of reconditioned brackets.
Wright, W L; Powers, J M
1985-03-01
This study evaluated the effects of four rebonding procedures on in vitro tensile bond strength of four filled diacrylate adhesives on orthodontic brackets. The four procedures were thermal reconditioning, chemical reconditioning, removal of residual adhesive with a green stone, and grinding the mesh base with a green stone. The mesh-base, stainless steel brackets were bonded to plastic cylinders and the tensile bond force necessary to cause bond failure was recorded. The initial bond strengths for the no-mix adhesive and both two-paste systems were significantly greater than the tensile bond strengths for any rebonding condition. Different rebonding conditions reduced tensile bone strength to differing degrees, using each of these three adhesives. The initial bond strength for the visible, light-cured adhesive was not significantly different from three of the four rebonding conditions and was lower than the initial bond strength of the other three adhesives.
Derivation of the Hall and extended magnetohydrodynamics brackets
D'Avignon, Eric C. Morrison, Philip J.; Lingam, Manasvi
2016-06-15
There are several plasma models intermediate in complexity between ideal magnetohydrodynamics (MHD) and two-fluid theory, with Hall and Extended MHD being two important examples. In this paper, we investigate several aspects of these theories, with the ultimate goal of deriving the noncanonical Poisson brackets used in their Hamiltonian formulations. We present fully Lagrangian actions for each, as opposed to the fully Eulerian, or mixed Eulerian-Lagrangian, actions that have appeared previously. As an important step in this process, we exhibit each theory's two advected fluxes (in analogy to ideal MHD's advected magnetic flux), discovering also that with the correct choice of gauge they have corresponding Lie-dragged potentials resembling the electromagnetic vector potential, and associated conserved helicities. Finally, using the Euler-Lagrange map, we show how to derive the noncanonical Eulerian brackets from canonical Lagrangian ones.
Derivation of the Hall and Extended Magnetohydrodynamics Brackets
NASA Astrophysics Data System (ADS)
D'Avignon, Eric; Lingam, Manasvi; Morrison, Philip
2016-10-01
There are several plasma models intermediate in complexity between ideal magnetohydrodynamics (MHD) and two-fluid theory, with Hall and Extended MHD being two important examples. In this research we investigate several aspects of these theories, with the ultimate goal of deriving the noncanonical Poisson brackets used in their Hamiltonian formulations. We present fully Lagrangian actions for each, as opposed to the fully Eulerian, or mixed Eulerian-Lagrangian, actions that have appeared previously. As an important step in this process we exhibit each theory's two advected fluxes (in analogy to ideal MHD's advected magnetic flux), discovering also that with the correct choice of gauge they have corresponding Lie-dragged potentials resembling the electromagnetic vector potential, and associated conserved helicities. Finally, using the Euler-Lagrange map, we show how to derive the noncanonical Eulerian brackets from canonical Lagrangian ones.
[Considerations in orthodontic bracket adhesion to hypoplastic and hypomineralized enamel].
Sapir, S
2007-01-01
Developmental defects of enamel are frequently observed in the pediatric and orthodontic dental clinic. Proper diagnosis may improve the clinician's dental care. The importance of prevention is emphasized as well as the proper management of adhesion of orthodontic brackets to hypoplastic and hypominerilized enamel. A review of recent research findings in this field is discussed as well as recommendations for clinical management of some common dental defects: hypoplasia, diffuse and demarcated opacities, and amelogenesis imperfecta.
Orthodontic bracket bonding to glazed full-contour zirconia
Kwak, Ji-Young; Jung, Hyo-Kyung; Choi, Il-Kyung
2016-01-01
Objectives This study evaluated the effects of different surface conditioning methods on the bond strength of orthodontic brackets to glazed full-zirconia surfaces. Materials and Methods Glazed zirconia (except for the control, Zirkonzahn Prettau) disc surfaces were pre-treated: PO (control), polishing; BR, bur roughening; PP, cleaning with a prophy cup and pumice; HF, hydrofluoric acid etching; AA, air abrasion with aluminum oxide; CJ, CoJet-Sand. The surfaces were examined using profilometry, scanning electron microscopy, and electron dispersive spectroscopy. A zirconia primer (Z-Prime Plus, Z) or a silane primer (Monobond-S, S) was then applied to the surfaces, yielding 7 groups (PO-Z, BR-Z, PP-S, HF-S, AA-S, AA-Z, and CJ-S). Metal bracket-bonded specimens were stored in water for 24 hr at 37℃, and thermocycled for 1,000 cycles. Their bond strengths were measured using the wire loop method (n = 10). Results Except for BR, the surface pre-treatments failed to expose the zirconia substructure. A significant difference in bond strengths was found between AA-Z (4.60 ± 1.08 MPa) and all other groups (13.38 ± 2.57 - 15.78 ± 2.39 MPa, p < 0.05). For AA-Z, most of the adhesive remained on the bracket. Conclusions For bracket bonding to glazed zirconia, a simple application of silane to the cleaned surface is recommended. A zirconia primer should be used only when the zirconia substructure is definitely exposed. PMID:27200278
Indirect bonding of brackets: don't wait another day!
Pellan, Pierre
2007-01-01
Indirect bonding of orthodontic brackets is nothing new, but the introduction of more recent adhesives has increased the clinical success encountered by clinicians in a significant way. The many advantages of this technique over direct bonding make it worth the change. The aim of this article is to review the different variables of the technique and describe both laboratory and clinical procedures that have worked so well in hundreds of dental offices.
MS Malenchenko tapes brackets in Zvezda during STS-106
2000-09-13
S106-E-5175 (13 September) --- Cosmonaut Yuri I. Malenchenko, representing the Russian Aviation and Space Agency, tapes brackets for the Zvezda during work on the service module. The mission specialist and the other STS-106 astronauts and cosmonaut are continuing electrical work and transfer activities as they near the halfway point of docked operations with the International Space Station. In all the crew will have 189 hours, 40 minutes of planned Atlantis-ISS docked time.
12. FLOOR BEAMS, BRACKETS, STRINGERS. (Also includes a schedule of ...
12. FLOOR BEAMS, BRACKETS, STRINGERS. (Also includes a schedule of parts.) American Bridge Company, Ambridge Plant No. 5, sheet no. 2, dated April 2, 1928 (revised 4-24-28), order no. F5073. For U.S. Steel Products Company, Pacific Coast Depot, order no. SF578. For Southern Pacific Company, order no. 8873-P-28746. Scale 1/4 inch to one foot. - Napa River Railroad Bridge, Spanning Napa River, east of Soscol Avenue, Napa, Napa County, CA
ERIC Educational Resources Information Center
Hewitt, Dave
2012-01-01
This study looks at a mixed ability group of 21 Year 5 primary students (aged 9-10 years old) who had previously never had formal instruction using letters to stand for unknowns or variables in a mathematics context; nor had they been introduced to formal algebraic notation. Three lessons were taught using the computer software "Grid Algebra"…
Perceptions of Schooling, Pedagogy and Notation in the Lives of Visually-Impaired Musicians
ERIC Educational Resources Information Center
Baker, David; Green, Lucy
2016-01-01
This article discusses findings on schooling, pedagogy and notation in the life-experiences of amateur and professional visually-impaired musicians/music teachers, and the professional experiences of sighted music teachers who work with visually-impaired learners. The study formed part of a broader UK Arts and Humanities Research Council funded…
Development of a Notational Analysis System for Selected Soccer Skills of a Women's College Team
ERIC Educational Resources Information Center
Thomas, Camille; Fellingham, Gilbert; Vehrs, Pat
2009-01-01
The purposes of this study were to develop a notational system to evaluate passing, dribbling, first touch, and individual defensive skills as they relate to success during women's soccer games and to develop a statistical model to weigh the importance of each skill on creating scoring opportunities. Sequences of skills in ten games of a National…
Children's Invented Notations and Verbal Responses to a Piano Work by Claude Debussy
ERIC Educational Resources Information Center
Elkoshi, Rivka
2015-01-01
This study considers the way children listen to classical music composed for them and the effect of age on their spontaneous invented notations and verbal responses. The musical selection is a piano piece for children by Claude Debussy:"'Jimbo's Lullaby" from "Children's Corner". Two hundred and nine children 4-9.5-years-old…
ERIC Educational Resources Information Center
Tan, Siu-Lan; Wakefield, Elizabeth M.; Jeffries, Paul W.
2009-01-01
Fifty participants who had never learned how to read music completed a questionnaire about their interpretations of standard western musical notation. Some common assumptions were that a note must consist of a circle plus a line, symbols with unfilled spaces denote silence, the value of notes and rests increases with the size and number of…
19 CFR 141.90 - Notation of tariff classification and value on invoice.
Code of Federal Regulations, 2010 CFR
2010-04-01
... being entered. Except when invoice line data are linked to an entry summary line and transmitted to CBP... notations in blue or black ink. Except when invoice line data are linked to an entry summary line and... include on the invoice or with the invoice data the appropriate subheading under the provisions of...
A Comparison of Programming Languages and Algebraic Notation as Expressive Languages for Physics.
ERIC Educational Resources Information Center
Sherin, Bruce L.
2001-01-01
Considers some of the implications of replacing, for the purposes of physics instruction, algebraic notation with programming language. Introduces a framework based on two theoretical constructs. Concludes that algebra-physics can be characterized as the physics of balance and equilibrium and programming-physics as the physics of processes and…
A Computer Process for Substructure Searches on Compound Structures Ciphered in the IUPAC Notation
ERIC Educational Resources Information Center
Polton, D. J.
1972-01-01
Computer programs have been written which enable substructure searches to be carried out on a file of compounds ciphered using a modified version of the IUPAC (Dyson) notation. The search system outlined is to be linked with one which uses input from the chemical structure typewriter. (3 references) (Author)
Reading a Note, Reading a Mind: Children's Notating Skills and Understanding of Mind
ERIC Educational Resources Information Center
Leyva, Diana; Hopson, Sarah; Nichols, Ashley
2012-01-01
Are children's understanding of mental states (understanding of mind) related to their notating skills, that is, their ability to produce and read written marks to convey information about objects and number? Fifty-three preschoolers and kindergarteners were presented with a dictation task where they produced some written marks and were later…
The Role of Visual Representations in College Students’ Understanding of Mathematical Notation
Atagi, Natsuki; DeWolf, Melissa; Stigler, James W.; Johnson, Scott P.
2016-01-01
Developing understanding of fractions involves connections between non-symbolic visual representations and symbolic representations. Initially, teachers introduce fraction concepts with visual representations before moving to symbolic representations. Once the focus is shifted to symbolic representations, the connections between visual representations and symbolic notation are considered to be less useful, and students are rarely asked to connect symbolic notation back to visual representations. In two experiments, we ask whether visual representations affect understanding of symbolic notation for adults who understand symbolic notation. In a conceptual fraction comparison task (e.g., Which is larger, 5a or 8a?), participants were given comparisons paired with accurate, helpful visual representations, misleading visual representations, or no visual representations. The results show that even college students perform significantly better when accurate visuals are provided over misleading or no visuals. Further, eye-tracking data suggest that these visual representations may affect performance even when only briefly looked at. Implications for theories of fraction understanding and education are discussed. PMID:27253680
Elmarakeby, Haitham; Arefiyan, Mostafa; Myers, Elijah; Li, Song; Grene, Ruth; Heath, Lenwood S
2017-08-28
The Beacon Editor is a cross-platform desktop application for the creation and modification of signal transduction pathways using the Systems Biology Graphical Notation Activity Flow (SBGN-AF) language. Prompted by biologists' requests for enhancements, the Beacon Editor includes numerous powerful features for the benefit of creation and presentation.
Perceptions of Schooling, Pedagogy and Notation in the Lives of Visually-Impaired Musicians
ERIC Educational Resources Information Center
Baker, David; Green, Lucy
2016-01-01
This article discusses findings on schooling, pedagogy and notation in the life-experiences of amateur and professional visually-impaired musicians/music teachers, and the professional experiences of sighted music teachers who work with visually-impaired learners. The study formed part of a broader UK Arts and Humanities Research Council funded…
ERIC Educational Resources Information Center
Blanton, Maria; Brizuela, Bárbara M.; Gardiner, Angela Murphy; Sawrey, Katie; Newman-Owens, Ashley
2017-01-01
Recent research suggests that children in elementary grades have some facility with variable and variable notation in ways that warrant closer attention. We report here on an empirically developed progression in first-grade children's thinking about these concepts in functional relationships. Using learning trajectories research as a framework for…
43 CFR 3815.8 - Notation required in application for patent; conditions required in patent.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Notation required in application for patent; conditions required in patent. 3815.8 Section 3815.8 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LANDS AND MINERALS SUBJECT TO LOCATION...
43 CFR 3815.8 - Notation required in application for patent; conditions required in patent.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Notation required in application for patent; conditions required in patent. 3815.8 Section 3815.8 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LANDS AND MINERALS SUBJECT TO LOCATION...
43 CFR 3815.8 - Notation required in application for patent; conditions required in patent.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Notation required in application for patent; conditions required in patent. 3815.8 Section 3815.8 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LANDS AND MINERALS SUBJECT TO LOCATION...
43 CFR 3815.8 - Notation required in application for patent; conditions required in patent.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Notation required in application for patent; conditions required in patent. 3815.8 Section 3815.8 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LANDS AND MINERALS SUBJECT TO LOCATION...
ERIC Educational Resources Information Center
Pramling, Niklas
2009-01-01
This study concerns children's representational knowledge, more specifically, their "invented notations" of music. A small-scale empirical study of four 5-year-old children and their teachers working on the representation of music is reported. The challenges posed by the teachers and how the children respond to these challenges are analysed. The…
Reading a Note, Reading a Mind: Children's Notating Skills and Understanding of Mind
ERIC Educational Resources Information Center
Leyva, Diana; Hopson, Sarah; Nichols, Ashley
2012-01-01
Are children's understanding of mental states (understanding of mind) related to their notating skills, that is, their ability to produce and read written marks to convey information about objects and number? Fifty-three preschoolers and kindergarteners were presented with a dictation task where they produced some written marks and were later…
Children's Use of Variables and Variable Notation to Represent Their Algebraic Ideas
ERIC Educational Resources Information Center
Brizuela, Bárbara M.; Blanton, Maria; Sawrey, Katharine; Newman-Owens, Ashley; Murphy Gardiner, Angela
2015-01-01
In this article, we analyze a first grade classroom episode and individual interviews with students who participated in that classroom event to provide evidence of the variety of understandings about variable and variable notation held by first grade children approximately six years of age. Our findings illustrate that given the opportunity,…
ERIC Educational Resources Information Center
Tan, Siu-Lan; Wakefield, Elizabeth M.; Jeffries, Paul W.
2009-01-01
Fifty participants who had never learned how to read music completed a questionnaire about their interpretations of standard western musical notation. Some common assumptions were that a note must consist of a circle plus a line, symbols with unfilled spaces denote silence, the value of notes and rests increases with the size and number of…
TASI 2011 Lectures Notes:. Two-Component Fermion Notation and Supersymmetry
NASA Astrophysics Data System (ADS)
Martin, Stephen P.
2013-12-01
These notes, based on work with Herbi Dreiner and Howie Haber, discuss how to do practical calculations of cross sections and decay rates using two-component fermion notation, as appropriate for supersymmetry and other beyond-the-Standard-Model theories. Included are a list of two-component fermion Feynman rules for the Minimal Supersymmetric Standard Model, and some example calculations.
Goal Structured Notation in a Radiation Hardening Safety Case for COTS-Based Spacecraft
NASA Technical Reports Server (NTRS)
Witulski, Arthur; Austin, Rebekah; Reed, Robert; Karsai, Gabor; Mahadevan, Nag; Sierawski, Brian; Evans, John; LaBel, Ken
2016-01-01
A systematic approach is presented to constructing a radiation assurance case using Goal Structured Notation (GSN) for spacecraft containing COTS parts. The GSN paradigm is applied to an SRAM single-event upset experiment board designed to fly on a CubeSat November 2016. Construction of a radiation assurance case without use of hardened parts or extensive radiation testing is discussed.
Children's Use of Variables and Variable Notation to Represent Their Algebraic Ideas
ERIC Educational Resources Information Center
Brizuela, Bárbara M.; Blanton, Maria; Sawrey, Katharine; Newman-Owens, Ashley; Murphy Gardiner, Angela
2015-01-01
In this article, we analyze a first grade classroom episode and individual interviews with students who participated in that classroom event to provide evidence of the variety of understandings about variable and variable notation held by first grade children approximately six years of age. Our findings illustrate that given the opportunity,…
Children's Invented Notations and Verbal Responses to a Piano Work by Claude Debussy
ERIC Educational Resources Information Center
Elkoshi, Rivka
2015-01-01
This study considers the way children listen to classical music composed for them and the effect of age on their spontaneous invented notations and verbal responses. The musical selection is a piano piece for children by Claude Debussy:"'Jimbo's Lullaby" from "Children's Corner". Two hundred and nine children 4-9.5-years-old…
Yanase, Yumi; Ioi, Hideki; Uehara, Michiya; Hara, Atsushi; Nakata, Shunsuke; Nakasima, Akihiko; Counts, Amy L
2009-01-01
To compare the kinetic frictional force of a conventional plastic preadjusted bracket with thermoplastic low-friction module ligation and a self-ligating bracket. The testing model consisted of four 0.022-inch conventional plastic preadjusted brackets; four 0.022-inch self-ligating brackets for the first premolar, canine, and lateral and central incisors; and a 0.014-inch superelastic nickel-titanium and a 0.019 × 0.025-inch stainless steel wire. The brackets were either aligned for both wires or out of line by 0.5, 1.0, 1.5, and 2.0 mm for only the 0.014-inch superelastic wire. The wires were pulled for 3.0 mm at a speed of 0.1 mm per second. Unpaired t tests were used to compare the mean differences of the measurements between the two bracket systems with both wires. No significant difference in the kinetic frictional force between the two bracket systems and the two wires were found for the 0.014-inch superelastic wire at 0-mm deflection. Both bracket systems demonstrate low friction, which is beneficial for effective orthodontic tooth movement with light forces. © 2009 BY QUINTESSENCE PUBLISHING CO, INC.
Corrosion of orthodontic brackets in different spices: in vitro study.
Chaturvedi, T P
2014-01-01
Moist environment in the mouth varies and causes variable amounts of corrosion of dental materials. This is of concern particularly when metallic implants, metallic fillings, orthodontic appliances are placed in the hostile electrolytic environment in the human mouth. Components of diet rich in salt and spices are important factors influencing the corrosion of metallic appliances placed in the oral cavity. To study in vitro corrosion of orthodontic metallic brackets immersed in solutions of salt and spices in artificial saliva. Orthodontic brackets were used for corrosion studies in artificial saliva, salt, and spices using electrochemical technique and surface analysis. Electrochemical studies using different parameters were done in solutions of artificial saliva containing salt and spices. Photomicrographs from the optical microscope were also obtained. RESULTS of corrosion studies have clearly demonstrated that certain spices such as turmeric and coriander are effective in reducing corrosion, whereas salt and red chili have been found to enhance it. Surface analysis of small pits present on the surface of the as-received bracket will initiate corrosion which leads to more pitting.
Applicative Characteristics of a New Zirconia Bracket with Multiple Slots
Maki, Koutaro; Futaki, Katsuyoshi; Tanabe, Satoru; Takahashi, Mariko; Ichikawa, Yuta; Yamaguchi, Tetsutaro
2016-01-01
We have developed a new orthodontic bracket with three slots with lubricative properties on the working surfaces and proposed a new orthodontic treatment system employing 0.012−0.014-inch Ni-Ti arch wires. We recruited 54 patients, of which 27 received treatment with the new zirconia bracket with multiple slots system (M group), and the others received treatment with standard edge-wise appliances (control group [C group]). We compared the (1) tooth movement rate at the early stage of leveling; (2) changes in the dental arch morphology before and after leveling; and (3) pain caused by orthodontic treatment. Student's t-test was used in all assessments. The tooth movement rate in the maxillomandibular dentition was higher in the M group. The basal arch width, anterior length, and the intercanine width in the maxillary dentition were not significantly different in the two groups; however, the intercanine width in the mandibular dentition was higher in the C group. In assessments of treatment-related pain, the visual analogue pain score was 56.0 mm and 22.6 mm in the C and M groups, respectively. A new zirconia bracket with multiple slots system provided better outcomes with respect to tooth movement rate, treatment period, and postoperative pain, thus indicating its effectiveness over conventional orthodontic systems. PMID:27212948
Metallurgical characterization of orthodontic brackets produced by Metal Injection Molding (MIM).
Zinelis, Spiros; Annousaki, Olga; Makou, Margarita; Eliades, Theodore
2005-11-01
The aim of this study was to investigate the bonding base surface morphology, alloy type, microstructure, and hardness of four types of orthodontic brackets produced by Metal Injection Molding technology (Discovery, Extremo, Freedom, and Topic). The bonding base morphology of the brackets was evaluated by scanning electron microscopy (SEM). Brackets from each manufacturer were embedded in epoxy resin, and after metallographic grinding, polishing and coating were analyzed by x-ray energy-dispersive spectroscopic (EDS) microanalysis to assess their elemental composition. Then, the brackets were subjected to metallographic etching to reveal their metallurgical structure. The same specimen surfaces were repolished and used for Vickers microhardness measurements. The results were statistically analyzed with one-way analysis of variance and Student-Newman-Keuls multiple comparison test at the 0.05 level of significance. The findings of SEM observations showed a great variability in the base morphology design among the brackets tested. The x-ray EDS analysis demonstrated that each bracket was manufactured from different ferrous or Co-based alloys. Metallographic analysis showed the presence of a large grain size for the Discovery, Freedom, and Topic brackets and a much finer grain size for the Extremo bracket. Vickers hardness showed great variations among the brackets (Topic: 287 +/- 16, Freedom: 248 +/- 13, Discovery: 214 +/- 12, and Extremo: 154 +/- 9). The results of this study showed that there are significant differences in the base morphology, composition, microstructure, and microhardness among the brackets tested, which may anticipate significant clinical implications.
Effects of third-order torque on frictional force of self-ligating brackets.
Muguruma, Takeshi; Iijima, Masahiro; Brantley, William A; Ahluwalia, Karamdeep S; Kohda, Naohisa; Mizoguchi, Itaru
2014-11-01
To investigate the effects of third-order torque on frictional properties of self-ligating brackets (SLBs). Three SLBs (two passive and one active) and three archwires (0.016 × 0.022-inch nickel-titanium, and 0.017 × 0.025-inch and 0.019 × 0.025-inch stainless steel) were used. Static friction was measured by drawing archwires though bracket slots with four torque levels (0°, 10°, 20°, 30°), using a mechanical testing machine (n = 10). A conventional stainless-steel bracket was used for comparison. RESULTS were subjected to Kruskal-Wallis and Mann-Whitney U-tests. Contact between the bracket and wire was studied using a scanning electron microscope. In most bracket-wire combinations, increasing the torque produced a significant increase in static friction. Most SLB-wire combinations at all torques produced less friction than that from the conventional bracket. Active-type SLB-wire combinations showed higher friction than that from passive-type SLB-wire combinations in most conditions. When increasing the torque, more contact between the wall of a bracket slot and the edge of a wire was observed for all bracket types. Increasing torque when using SLBs causes an increase in friction, since contact between the bracket slot wall and the wire edge becomes greater; the design of brackets influences static friction.
Cacciafesta, Vittorio; Sfondrini, Maria Francesca; Melsen, Birte; Scribante, Andrea
2004-08-01
The purpose of this prospective longitudinal randomized study was to compare the clinical performance of recycled brackets with that of new stainless steel brackets (Orthos). Twenty patients treated with fixed appliances were included in the investigation. Using a 'split-mouth' design, the dentition of each patient was divided into four quadrants. In 11 randomly selected patients, the maxillary left and mandibular right quadrants were bonded with recycled brackets, and the remaining quadrants with new stainless steel brackets. In the other nine patients the quadrants were inverted. Three hundred and ten stainless steel brackets were examined: 156 were recycled and the remaining 154 were new. All the brackets were bonded with a self-cured resin-modified glass ionomer (GC Fuji Ortho). The number, cause, and date of bracket failures were recorded over 12 months. Statistical analysis was performed by means of a paired t-test, Kaplan-Meier survival estimates, and the log-rank test. No statistically significant differences were found between: (a) the total bond failure rate of recycled and new stainless steel brackets; (b) the upper and lower arches; (c) the anterior and posterior segments. These findings demonstrate that recycling metallic orthodontic brackets can be of benefit to the profession, both economically and ecologically, as long as the orthodontist is aware of the various aspects of the recycling methods, and that patients are informed about the type of bracket that will be used for their treatment.
NASA Astrophysics Data System (ADS)
Woods, David Keith
The purpose of this study was to analyze the resistance to sliding of coated rectangular fiber reinforced composite archwires using various brackets systems and second-order bracket angulations. Resistance to sliding was investigated for eight bracket systems: six self-ligating brackets (four passive and two passive-active) and two conventional brackets. A rectangular fiber reinforced composite archwire of 0.019 x 0.025-in dimension from BiomersRTM SimpliClear was drawn through a three-bracket model system at ten millimeters per minute for 2.5 millimeters. For each bracket, the resistance to sliding was measured at four bracket angulations (0°, 2.5°, 5°, and 10°) in a dry state at room temperature. The fiber reinforced composite archwire produced the lowest sliding resistance with the passive self-ligating bracket system (Damon DQ) at each bracket angulation tested. Overall, self-ligating bracket systems generated lower sliding resistance than conventionally ligated systems, and one passive/active self-ligating bracket system (In-Ovation-R). There was a significant increase in resistance to sliding as bracket angulation increased for all bracket systems tested. Microscopic analysis revealed increased perforation of the archwire coating material as bracket angulations were increased. Our findings show that the rectangular fiber reinforced composite archwire may be acceptable for sliding mechanics during the intermediate stages of orthodontic tooth movement, however more long-term studies are needed.
Shin, Kyungsup
2017-06-01
The effect of bracket ligation on the periodontal status of adolescents undergoing orthodontic treatment. A systematic review and meta-analysis. Arnold S, Koletsi D, Patcas R, Eliades T. J Dent 2016; 54:13-24. The authors did not report any funding source information for the study TYPE OF STUDY/DESIGN: Systematic review with meta-analysis of data. Copyright © 2017 Elsevier Inc. All rights reserved.
A comparative assessment of torque generated by lingual and conventional brackets.
Sifakakis, Iosif; Pandis, Nikolaos; Makou, Margarita; Eliades, Theodore; Katsaros, Christos; Bourauel, Christoph
2013-06-01
The aim of this study was to assess the effect of bracket type on the labiopalatal moments generated by lingual and conventional brackets. Incognito™ lingual brackets (3M Unitek), STb™ lingual brackets (Light Lingual System; ORMCO), In-Ovation L lingual brackets (DENTSPLY GAC), and conventional 0.018 inch slot brackets (Gemini; 3M Unitek) were bonded on identical maxillary acrylic resin models with levelled and aligned teeth. Each model was mounted on the orthodontic measurement and simulation system and 10 0.0175 × 0.0175 TMA wires were used for each bracket type. The wire was ligated with elastomerics into the Incognito, STb, and conventional brackets and each measurement was repeated once after religation. A 15 degrees buccal root torque (+15 degrees) and then a 15 degrees palatal root torque (-15 degrees) were gradually applied to the right central incisor bracket. After each activation, the bracket returned to its initial position and the moments in the sagittal plane were recorded during these rotations of the bracket. One-way analysis of variance with post hoc multiple comparisons (Tukey test at 0.05 error rate) was conducted to assess the effect on bracket type on the generated moments. The magnitude of maximum moment at +15 degrees ranged 8.8, 8.2, 7.1, and 5.8 Nmm for the Incognito, STb, conventional Gemini, and the In-Ovation L brackets, respectively; similar values were recorded at -15 degrees: 8.6, 8.1, 7.0, and 5.7 Nmm, respectively. The recorded differences of maximum moments were statistically significant, except between the Incognito and STb brackets. Additionally, the torque angles were evaluated at which the crown torque fell well below the minimum levels of 5.0 Nmm, as well as the moment/torque ratio at the last part of the activation/deactivation curve, between 10 and 15 degrees. The lowest torque expression was observed at the self-ligating lingual brackets, followed by the conventional brackets. The Incognito and STb lingual brackets
Cheng, Peter C-H
2011-07-01
The representational epistemic approach to the design of visual displays and notation systems advocates encoding the fundamental conceptual structure of a knowledge domain directly in the structure of a representational system. It is claimed that representations so designed will benefit from greater semantic transparency, which enhances comprehension and ease of learning, and plastic generativity, which makes the meaningful manipulation of the representation easier and less error prone. Epistemic principles for encoding fundamental conceptual structures directly in representational schemes are described. The diagrammatic recodification of probability theory is undertaken to demonstrate how the fundamental conceptual structure of a knowledge domain can be analyzed, how the identified conceptual structure may be encoded in a representational system, and the cognitive benefits that follow. An experiment shows the new probability space diagrams are superior to the conventional approach for learning this conceptually challenging topic.
NASA Astrophysics Data System (ADS)
Kim, Tae-Won; Lim, Sang-Sub; Seok, Ho-Hyun; Kang, Chung-Gil
2013-09-01
Brackets in ships and offshore structures are added structures that can endure stress concentrations. In this study, a concurrent engineering solution was proposed, and a high strength low carbon cast steel alloy applicable to offshore structures was designed and developed. The yield strength and ultimate tensile strength of the designed steel were 480 and 600 MPa, respectively. The carbon equivalent of the steel was 0.446 with a weld crack susceptibility index of 0.219. The optimal structural design of the brackets for offshore structures was evaluated using ANSYS commercial software. The possibility of replacing an assembly of conventional built-up brackets with a single casting bulb bracket was verified. The casting process was simulated using MAGMAsoft commercial software, and a casting fabrication process was designed. For the proposed bulb bracket, it was possible to reduce the size and weight by approximately 30% and 50%, respectively, compared to the conventional type of bracket.
Shear Bond Strength of DentStat(trademark) for Bracket Bonding to Gold, Ceramic, and Enamel
2012-12-21
brackets were bonded to type III gold, feldspathic porcelain and bovine enamel by using DentStatTM as the adhesive . When DentStatTM was used as the...the demineralization of enamel around the bracket. The advent of a new dental adhesive in 1971 was presumed to help resolve some of the problems seen...porcelain, and enamel . Both adhesives will be used to bond Victory Series MBTTM.022 twin maxillary right central incisor brackets (3M Unitek Monrovia
Effect of Er:YAG Laser and Sandblasting in Recycling of Ceramic Brackets
Yassaei, Soghra; Aghili, Hossein; Hosseinzadeh Firouzabadi, Azadeh; Meshkani, Hamidreza
2017-01-01
Introduction: This study was performed to determine the shear bond strength of rebonded mechanically retentive ceramic brackets after recycling with Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) laser or sandblasting. Methods: Twenty-eight debonded ceramic brackets plus 14 intact new ceramic brackets were used in this study. Debonded brackets were randomly divided into 2 groups of 14. One group was treated by Er:YAG laser and the other with sandblasting. All the specimens were randomly bonded to 42 intact human upper premolars. The shear bond strength of all specimens was determined with a universal testing machine at a crosshead speed of 0.5 mm/min until bond failure occurred. The recycled bracket base surfaces were observed under a scanning electron microscope (SEM). Analysis of variance (ANOVA) and Tukey tests were used to compare the shear bond strength of the 3 groups. Fisher exact test was used to evaluate the differences in adhesive remnant index (ARI) scores. Results: The highest bond strength belonged to brackets recycled by Sandblasting (16.83 MPa). There was no significant difference between the shear bond strength of laser and control groups. SEM photographs showed differences in 2 recycling methods. The laser recycled bracket appeared to have as well-cleaned base as the new bracket. Although the sandblasted bracket photographs showed no remnant adhesives, remarkable micro-roughening of the base of the bracket was apparent. Conclusion: According to the results of this study, both Er:YAG laser and sandblasting were efficient to mechanically recondition retentive ceramic brackets. Also, Er:YAG laser did not change the design of bracket base while removing the remnant adhesives which might encourage its application in clinical practice. PMID:28912939
Degradation of plastic polyoxymethylene brackets and the subsequent release of toxic formaldehyde.
Kusy, Robert P; Whitley, John Q
2005-04-01
Heat, acids, alkalis, oxygen, abrasion, enzymes, and radiation are all viable mechanisms for the chemical breakdown of polyoxymethylene (POM), a plastic material used in some esthetic orthodontic brackets. The aim of this study was to establish the thermal characteristics of POM brackets and the chemical by-products in the as-received bracket, during thermal analyses of the bracket, and after abrasion of the slot and base of the bracket. Plastic brackets and control rods made of POM were evaluated ex vivo by thermal and chemical analyses. POM brackets produce toxic formaldehyde gas whether heated or mechanically abraded. Patients who wear these brackets are being exposed to, at the very least, a potential irritant. Thermal analyses showed that the melting temperature of a POM bracket was approximately 178 degrees C, comparable to that for a commercial rod of POM. Both POM products started to degrade at approximately 250 degrees C, and, by 420 degrees C, both products had completely decomposed into their fundamental molecular structure, formaldehyde. A colorimetric assay with a fuchsin-aldehyde reagent (Schiff's reagent) showed that aldehydes were present in the effluent from thermal heating, from mechanical abrasion of the bracket's slot or base, and even from the as-received bracket. The only difference between the 6 to 8-week assays and the 12 to 14-week assays was the intensification of the color, which occurred because of an increase in aldehyde formation and the concomitant increase in double-bond formation. These observations are consistent with a report in the tribologic (ie, friction and wear) literature, which documented the degradation of POM when it rubs against steel. Because formaldehyde's inherent uses as a disinfectant base and embalming fluid preclude its beneficial presence in the human body, further use of POM for orthodontic brackets, crowns for children, and other prosthetic appliances is contraindicated because even radiography will promote its
Pimentel, Roberta Ferreira; de Oliveira, Roberto Sotto Maior Fortes; Chaves, Maria das Graças Afonso Miranda; Elias, Carlos Nelson; Gravina, Marco Abdo
2013-01-01
To evaluate and compare "in vitro" the maximum friction force generated by three types of esthetic brackets, two types of polycrystalline conventional ceramic brackets (20/40 and InVu) and one type of sapphire monocrystalline bracket (Radiance) in dry and artificial saliva wet settings. Also, to evaluate the influence exerted by artificial saliva on the friction forces of those brackets. Tests were performed in dry and artificial saliva wet setting (Oral Balance) by using an EMIC DL 10000 testing machine, simulating a 2 mm slide of 0.019 x 0.025-in rectangular stainless steel wires over the pre-angulated and pre-torqued (right superior canine, Roth prescription, slot 0.022 x 0.030-in) brackets (n = 18 for each bracket). In order to compare groups in dry and wet settings, the ANOVA was used. For comparisons related to the dry versus wet setting, the student t test was used for each group. The results showed that in the absence of saliva the Radiance monocrystalline brackets showed the highest friction coefficients, followed by the 20/40 and the InVu polycrystalline brackets. In tests with artificial saliva, the Radiance and the 20/40 brackets had statistically similar friction coefficients and both were greater than that presented by the InVu brackets. The artificial saliva did not change the maximum friction force of the Radiance brackets, but, for the others (20/40 and InVu), an increase of friction was observed in its presence. The InVu brackets showed, in the absence and in the presence of saliva, the lowest friction coefficient.
Intraoral corrosion of self-ligating metallic brackets and archwires and the effect on friction
NASA Astrophysics Data System (ADS)
Tima, Lori Lynn
The purpose of this study was to investigate how the frictional coefficient was affected due to intraoral use. A secondary aim of this study was to determine whether or not there was a relationship between corrosion of orthodontic alloys and friction via scanning electron microscopic qualitative analysis. Orthodontic brackets and 0.019 x 0.025 inch stainless steel archwires were collected and divided into three groups of n=10: used bracket and used wires (UBUW), used brackets and new wires (UBNW), and new brackets and new wires (NBNW). New materials were as-received from the manufacturer, and used materials were clinically used bracket and wires collected from patients following orthodontic treatment. Archwires were pulled through bracket slots at a rate of 0.5mm/min while friction forces were measured. Following a cleaning process, the surface topography of the bracket slots was examined under a scanning electron microscope (SEM). Based on a 1-factor MANOVA, there was no significant group effect (all p>0.05) on frictional forces. Partial eta squared values indicated that intraoral exposure had only a small effect on frictional forces (≤ 3%). Qualitative analysis of SEM images did not show an association between surface characteristics of the bracket slots and magnitude of frictional force. Results suggest that surface corrosion from intraoral use does not significantly affect friction at the bracket wire interface.
Deguchi, T; Ito, M; Obata, A; Koh, Y; Yamagishi, T; Oshida, Y
1996-07-01
Safety and esthetics are two indispensable factors to consider when fabricating orthodontic brackets. However, these factors are not easily achieved when conventional techniques (including forging and casting) are used in the mass production of titanium brackets, albeit the brackets exhibit excellent biocompatibility. In the present study, orthodontic brackets were manufactured by metal powder injection molding with sintering. Brackets with three different base designs were made and subjected to compression shear tests for evaluation of their bonding strength to enamel substrate. The shapes given to the dimple of the base were spherical, oval, and grooved. The maximum shear forces for each type were 11.1 kgf, 7.6 kgf, and 18.5 kgf, respectively. The bonding strengths of the titanium bracket were equivalent to those obtained with conventional stainless steel brackets. Moreover, uniform distribution of Vickers hardness values (average, 240 +/- 40 Hv) measured at three locations indicated that the titanium bracket was uniformly sintered. Accordingly, titanium brackets thus fabricated exhibit a potential for clinical application.
Influence of different orthodontic brackets on adherence of microorganisms in vitro.
Brusca, M I; Chara, O; Sterin-Borda, L; Rosa, A C
2007-03-01
To define the capacity of different bracket materials to modify the growth and adherence of microorganisms. Three types of brackets from the right upper central incisor were used: metallic, ceramic, and composite. Streptococcus mutans and Candida albicans were studied. The association of both species was also evaluated. The brackets were placed in flat-bottomed vials containing basal medium with 20% sucrose added; the flasks were inoculated with each of the microbial suspensions. The samples were incubated at 37 degrees C for 48 hours, after which the brackets were removed. The supernatant was removed from the flasks, the cells adhering to the glass were counted, and the brackets were studied with electron microscopy. The adherence of Streptococcus mutans was not modified by the different brackets. The adherence of Candida albicans was increased by the composite bracket, whereas the use of metallic brackets decreased the number of colony-forming units (CFUs). By electron microscopy we demonstrated that the adherence of Streptococcus mutans plus Candida albicans together varied according to the bracket materials with composite > ceramic > metallic. Orthodontic appliances serve as different impact zones and modify microbial adherence and colonization, acting as foreign reserves and possible sources of infection.
Leite, Brisa dos Santos; Fagundes, Nathalia Carolina Fernandes; Aragón, Mônica Lídia Castro; Dias, Carmen Gilda Barroso Tavares; Normando, David
2016-01-01
ABSTRACT Introduction: Debris buildup on the bracket-wire interface can influence friction. Cleansing brackets with air-powder polishing can affect this process. Objective: The aim of this study was to evaluate the frictional force and amount of debris remaining on orthodontic brackets subjected to prophylaxis with air-powder polishing. Methods: Frictional force and debris buildup on the surface of 28 premolar brackets were evaluated after orthodontic treatment. In one hemiarch, each bracket was subjected to air-powder polishing (n = 14) for five seconds, while the contralateral hemiarch (n = 14) served as control. Mechanical friction tests were performed and images of the polished bracket surfaces and control surfaces were examined. Wilcoxon test was applied for comparative analysis between hemiarches at p < 0.05. Results: Brackets that had been cleaned with air-powder polishing showed lower friction (median = 1.27 N) when compared to the control surfaces (median = 4.52 N) (p < 0.01). Image analysis showed that the control group exhibited greater debris buildup (median = 2.0) compared with the group that received prophylaxis with air-powder polishing (median = 0.5) (p < 0.05). Conclusion: Cleansing orthodontic brackets with air-powder polishing significantly reduces debris buildup on the bracket surface while decreasing friction levels observed during sliding mechanics. PMID:27653265
Kumar, Sujeet; Hamsa P.R, Rani; Ahmed, Sameer; Prasanthma; Bhatnagar, Apoorva; Sidhu, Manreet; Shetty, Pramod
2014-01-01
AIM: The aim of this study was to compare frictional resistance which was produced between conventional brackets (0.022 slot Otho-Organiser) and self ligating brackets (active Forestadent and passive Damon III) by using various arch wire combinations (0.016 Niti, 0.018 Niti, 0.017 x 0.025 SS and 0.019 x 0.025 SS). Methods: An experimental model which consisted of 5 aligned stainless steel 0.022-in brackets was used to assess frictional forces which were produced by SLBs (self ligating brackets) and CELs (conventional elastomeric ligatures) with use of 0.016 nickel titanium, 0.018 nickel titanium, 0.017 X 0.025”stainless steel and 0.019 X 0.025”stainless steel wires. Statistical analysis: One way ANOVA test was used to study the effect of the bracket type, wire alloy and section on frictional resistance test . Results: Conventional brackets produced highest levels of friction for all bracket/archwire combinations. Both Damon III and Forestadent brackets were found to produce significantly lower levels of friction when they were compared with elastomerically tied conventional brackets. Conclusion: SLBs are valid alternatives for low friction during sliding mechanics. PMID:24995241
Leite, Brisa Dos Santos; Fagundes, Nathalia Carolina Fernandes; Aragón, Mônica Lídia Castro; Dias, Carmen Gilda Barroso Tavares; Normando, David
2016-01-01
Debris buildup on the bracket-wire interface can influence friction. Cleansing brackets with air-powder polishing can affect this process. The aim of this study was to evaluate the frictional force and amount of debris remaining on orthodontic brackets subjected to prophylaxis with air-powder polishing. Frictional force and debris buildup on the surface of 28 premolar brackets were evaluated after orthodontic treatment. In one hemiarch, each bracket was subjected to air-powder polishing (n = 14) for five seconds, while the contralateral hemiarch (n = 14) served as control. Mechanical friction tests were performed and images of the polished bracket surfaces and control surfaces were examined. Wilcoxon test was applied for comparative analysis between hemiarches at p < 0.05. Brackets that had been cleaned with air-powder polishing showed lower friction (median = 1.27 N) when compared to the control surfaces (median = 4.52 N) (p < 0.01). Image analysis showed that the control group exhibited greater debris buildup (median = 2.0) compared with the group that received prophylaxis with air-powder polishing (median = 0.5) (p < 0.05). Cleansing orthodontic brackets with air-powder polishing significantly reduces debris buildup on the bracket surface while decreasing friction levels observed during sliding mechanics.
Elemental composition of brazing alloys in metallic orthodontic brackets.
Zinelis, Spiros; Annousaki, Olga; Eliades, Theodore; Makou, Margarita
2004-06-01
The aim of this study was to assess the elemental composition of the brazing alloy of representative orthodontic brackets. The brackets examined were Gemini (3M, Unitec, Monrovia, Calif), MicroLoc (GAC, Bohemia, NY), OptiMESHxrt (Ormco, Glendora, Calif), and Ultratrim (Dentarum, Ispringen, Germany). Four metallic brackets for each brand were embedded in epoxy resin and after metallographic grinding and polishing were cleaned in a water ultrasonic bath. Scanning electron microscopy and energy-dispersive x-ray microanalysis (EDS) were used to assess the quantitative composition of the brazing alloy. Four EDS spectra were collected for each brazing alloy, and the mean value and standard deviation for the concentration of each element were calculated. The elemental composition of the brazing alloys was determined as follows (percent weight): Gemini: Ni = 83.98 +/- 1.02, Si = 6.46 +/- 0.37, Fe = 5.90 +/- 0.93, Cr = 3.52 +/- 0.34; MicroLoc: Ag = 42.82 +/- 0.18, Au = 32.14 +/- 0.65, Cu = 24.53 +/- 0.26, Mg = 1.12 +/- 0.33; OptiMESHxrt: Au = 67.79 +/- 0.97, Fe = 15.69 +/- 0.29, Ni = 13.01 +/- 0.93, Cr = 4.01 +/- 0.35; Ultratrim: Ag = 87.97 +/- 0.33, Cu = 10.51 +/- 0.45, Mg = 1.29 +/- 0.63, Zn = 1.13 +/- 0.24. The findings of this study showed that different brazing materials were used for the different brands, and thus different performances are expected during intraoral exposure; potential effects on the biological properties also are discussed.
Future-singularity-free accelerating expansion with modified Poisson brackets
Kim, Wontae; Son, Edwin J.
2007-01-15
We show that the second accelerating expansion of the universe appears smoothly from the decelerating phase, which follows the initial inflation, in the two-dimensional soluble semiclassical dilaton gravity along with the modified Poisson brackets with noncommutativity between the relevant fields. This is in contrast to the fact that the ordinary solution of the equations of motion following from the conventional Poisson algebra describes a permanent accelerating universe without any phase change. In this modified model, it turns out that the noncommutative Poisson algebra is responsible for the remarkable phase transition to the second accelerating expansion.
Effect of brushing on fluoride release from 3 bracket adhesives.
Staley, Robert N; Mack, Steven J; Wefel, James S; Vargas, Marcos A; Jakobsen, Jane R
2004-09-01
The purpose of this in vitro study was to compare fluoride ion release from 3 orthodontic bracket adhesives with and without brushing the bracketed teeth with a fluoridated dentifrice. The bracket adhesives included a light-cured composite resin (Transbond; 3M Unitek, Monrovia, Calif), a fluoride-releasing composite resin (Advance; L D Caulk Division, Dentsply International, Milford, Del), and a resin-modified glass ionomer (Fuji Ortho LC; GC America, Alsip, Ill). The teeth in the control group were not bonded with brackets. Sixty extracted human teeth were randomly assigned to 6 groups of 10 each: (1) Transbond, brushed; (2) Advance, brushed; (3) Advance, not brushed; (4) Fuji, brushed; (5) Fuji, not brushed; and (6) control, brushed. After bonding, each tooth was placed in a sealed plastic test tube containing 4 ml of deionized water. The toothpaste used in brushing contained 0.15% weight per volume sodium fluoride, 1500 parts per million parts fluoride (Winter-fresh gel; Colgate-Palmolive Co., New York, NY). Brushing began 24 hours after the teeth were bonded and placed in deionized water. After brushing, the teeth were thoroughly rinsed with deionized water and returned to a sealed test tube. Fluoride measurements were taken before brushing began, at intervals of 72 hours for 22 days, and 90 and 93 days after bonding. Findings included: (1) brushing significantly increased the release of fluoride ions from the teeth in the composite resin and control groups, (2) the enamel crowns of the unbonded control teeth absorbed and re-released a substantial amount of fluoride ions obtained from the toothpaste, (3) the brushed group of teeth bonded with the fluoride-releasing composite resin released significantly more fluoride on the last 4 days that measurements were taken after brushing than the nonbrushed group bonded with the same adhesive, (4) the brushed group of teeth bonded with the resin-modified glass ionomer released significantly more fluoride on the last 4
Retraction of canines using bonded tube-brackets.
Davis, H D
1983-10-01
Investigations using a Force Analyser were carried out to test the characteristics of retractor springs fitted to a removable appliance and designed for insertion into a tube-bracket, bonded to the buccal surface of a canine. The retractors were shown to produce a counter-rotation couple when activated on the typodont. This type of canine retraction was then used clinically, and was found to produce less distal tilting than is noted with the single-point contact of a cantilever spring. Some spontaneous reduction in overjet was found to occur in each case of a small series. Possible mechanisms to account for this effect are discussed.
Maslov indices, Poisson brackets, and singular differential forms
NASA Astrophysics Data System (ADS)
Esterlis, I.; Haggard, H. M.; Hedeman, A.; Littlejohn, R. G.
2014-06-01
Maslov indices are integers that appear in semiclassical wave functions and quantization conditions. They are often notoriously difficult to compute. We present methods of computing the Maslov index that rely only on typically elementary Poisson brackets and simple linear algebra. We also present a singular differential form, whose integral along a curve gives the Maslov index of that curve. The form is closed but not exact, and transforms by an exact differential under canonical transformations. We illustrate the method with the 6j-symbol, which is important in angular-momentum theory and in quantum gravity.
Security analysis of an encryption scheme based on nonpositional polynomial notations
NASA Astrophysics Data System (ADS)
Kapalova, Nursulu; Dyusenbayev, Dilmukhanbet
2016-01-01
The aim of the research was to conduct a cryptographic analysis of an encryption scheme developed on the basis of nonpositional polynomial notations to estimate the algorithm strength. Nonpositional polynomial notations (NPNs) are residue number systems (RNSs) based on irreducible polynomials over GF(2). To evaluate if the algorithms developed on the basis of NPNs are secure, mathematical models of cryptanalysis involving algebraic, linear and differential methods have been designed. The cryptanalysis is as follows. A system of nonlinear equations is obtained from a function transforming plaintext into ciphertext with a key. Next, a possibility of transition of the nonlinear system to a linear one is considered. The cryptanalysis was conducted for the cases with known: 1) ciphertext; 2) plaintext and the related ciphertext; 3) plaintext file format; and 4) ASCII-encoded plaintext.
Perceptual expertise and top-down expectation of musical notation engages the primary visual cortex
Wong, Yetta Kwailing; Peng, Cynthia; Fratus, Kristyn N.; Woodman, Geoffrey F.; Gauthier, Isabel
2014-01-01
Most theories of visual processing propose that object recognition is achieved in higher visual cortex. However, we show that category selectivity for musical notation can be observed in the first event-related potential component called the C1 (measured 40-60ms after stimulus onset) with music-reading expertise. Moreover, the C1 note selectivity was observed only when the stimulus category was blocked but not when the stimulus category was randomized. Under blocking, the C1 activity for notes predicted individual music reading ability, and behavioral judgments of musical stimuli reflected music-reading skill. Our results challenge current theories of object recognition, indicating that the primary visual cortex can be selective for musical notation within the initial feedforward sweep of activity with perceptual expertise and with a testing context that is consistent with the expertise training, such as blocking the stimulus category for music reading. PMID:24666163
Kaur, Gagan Deep
2017-05-01
The design process in Kashmiri carpet weaving is distributed over a number of actors and artifacts and is mediated by a weaving notation called talim. The script encodes entire design in practice-specific symbols. This encoded script is decoded and interpreted via design-specific conventions by weavers to weave the design embedded in it. The cognitive properties of this notational system are described in the paper employing cognitive dimensions (CDs) framework of Green (People and computers, Cambridge University Press, Cambridge, 1989) and Blackwell et al. (Cognitive technology: instruments of mind-CT 2001, LNAI 2117, Springer, Berlin, 2001). After introduction to the practice, the design process is described in 'The design process' section which includes coding and decoding of talim. In 'Cognitive dimensions of talim' section, after briefly discussing CDs framework, the specific cognitive dimensions possessed by talim are described in detail.
Goal Structuring Notation in a Radiation Hardening Assurance Case for COTS-Based Spacecraft
2016-03-31
assurance case using Goal Structuring Notation (GSN) for spacecraft containing COTS parts. The GSN paradigm is applied to an SRAM single-event upset...or damage to an electronic device such as single- event latch up. The goal of this effort is to use GSN as a paradigm to create a safety case to... knowledge embodied by the models is drawn on for the assurance or safety case. The case itself can exist as a linked hierarchy facilitating a
Goal Structuring Notation in a Radiation Hardening Assurance Case for COTS-Based Spacecraft
NASA Technical Reports Server (NTRS)
Witulski, A.; Austin, R.; Evans, J.; Mahadevan, N.; Karsai, G.; Sierawski, B.; LaBel, K.; Reed, R.; Schrimpf, R.
2016-01-01
A systematic approach is presented to constructing a radiation assurance case using Goal Structuring Notation (GSN) for spacecraft containing COTS parts. The GSN paradigm is applied to an SRAM single-event upset experiment board designed to fly on a CubeSat in January 2017. A custom software language for development of a GSN assurance case is under development at Vanderbilt. Construction of a radiation assurance case without use of hardened parts or extensive radiation testing is discussed.
Goal Structuring Notation in a Radiation Hardening Assurance Case for COTS-Based Spacecraft
NASA Technical Reports Server (NTRS)
Witulski, Arthur; Austin, Rebekah; Evans, John; Mahadevan, Nag; Karsai, Gabor; Sierawski, Brian; LaBel, Ken; Reed, Robert; Schrimpf, Ron
2016-01-01
A systematic approach is presented to constructing a radiation assurance case using Goal Structuring Notation (GSN) for spacecraft containing commercial-off-the-shelf (COTS) parts. The GSN paradigm is applied to an SRAM single-event upset experiment board designed to fly on a CubeSat November 2016. Construction of a radiation assurance case without use of hardened parts or extensive radiation testing is discussed.
Spectrophotometric evaluation of dental bleaching under orthodontic bracket in enamel and dentin
Correr, Americo-Bortolazzo; Rastelli, Alessandra-Nara-Souza; Lima, Débora-Alves-Nunes-Leite; Consani, Rafael-Leonardo-Xediek
2014-01-01
Aware of the diffusion capacity of bleaching in the dental tissues, many orthodontists are subjecting their patients to dental bleaching during orthodontic treatment for esthetic purposes or to anticipate the exchange of esthetic restorations after the orthodontic treatment. For this purpose specific products have been developed in pre-loaded whitening trays designed to fit over and around brackets and wires, with clinical efficacy proven. Objective: The objective of this study was to evaluate, through spectrophotometric reflectance, the effectiveness of dental bleaching under orthodontic bracket. Material and Methods: Thirty-two bovine incisors crown blocks of 8 mm x 8 mm height lengths were used. Staining of tooth blocks with black tea was performed for six days. They were distributed randomly into 4 groups (1-home bleaching with bracket, 2- home bleaching without bracket, 3- office bleaching with bracket, 4 office bleaching without bracket). The color evaluation was performed (CIE L * a * b *) using color reflectance spectrophotometer. Metal brackets were bonded in groups 1 and 3. The groups 1 and 2 samples were subjected to the carbamide peroxide at 15%, 4 hours daily for 21 days. Groups 3 and 4 were subjected to 3 in-office bleaching treatment sessions, hydrogen peroxide 38%. After removal of the brackets, the second color evaluation was performed in tooth block, difference between the area under the bracket and around it, and after 7 days to verified color stability. Data analysis was performed using the paired t-test and two-way variance analysis and Tukey’s. Results: The home bleaching technique proved to be more effective compared to the office bleaching. There was a significant difference between the margin and center color values of the specimens that were subjected to bracket bonding. Conclusions: The bracket bond presence affected the effectiveness of both the home and office bleaching treatments. Key words:Tooth bleaching, spectrophotometry
Effects of modifying the adhesive composition on the bond strength of orthodontic brackets.
Bishara, Samir E; Ajlouni, Raed; Laffoon, John; Warren, John
2002-10-01
In an attempt to save chair time during bonding, metal brackets have been precoated with the adhesive material. Although the adhesive used on the precoated brackets is basically similar in composition to that used for bonding uncoated brackets, there are differences in the percentages of the various ingredients incorporated in the material. These changes are intended to enhance specific clinical properties. The purpose of this study was to determine whether modifications in the composition of the adhesives, used on precoated and uncoated metal brackets, affect their shear bond strengths during the first half hour after bonding. This is the time span when the initial arch wires are ligated. Sixty freshly extracted human molars were bonded with three different compositions of the same basic adhesive. The teeth were mounted in phenolic rings. An occlusogingival load was applied to the brackets producing a shear force at the bracket-tooth interface utilizing a Zwick Universal Test Machine. Analysis of variance was used to compare the three adhesives. Significance was predetermined at < or =.05 level of confidence. The present findings indicated that the shear bond strengths of the various modifications of the adhesive used on two different precoated metal brackets were not significantly different (F-ratio = .729 and P = .407) from those obtained with the conventional adhesive used on uncoated brackets. The mean values for the shear bond strengths of the two precoated brackets were: APC = 5.1+/-1.7 MPa and APC II = 4.9+/-2.1 MPa. The shear bond strength for the conventional adhesive used on the uncoated brackets was = 5.7+/-2.4 MPa. All bracket/adhesive combinations tested provided clinically acceptable shear bond forces within the first 30 minutes after initial bonding.
Turnbull, Nicholas R; Birnie, David J
2007-03-01
In this prospective clinical study, we assessed the relative speed of archwire changes, comparing self-ligating brackets with conventional elastomeric ligation methods, and further assessed this in relation to the stage of orthodontic treatment represented by different wire sizes and types. The time taken to remove and ligate archwires for 131 consecutive patients treated with either self-ligating or conventional brackets was prospectively assessed. The study was carried out in the orthodontic department of a district general hospital in the United Kingdom. The main outcome measure was the time to remove or place elastomeric ligatures or open/close self-ligating brackets for 2 matched groups of fixed appliance patients: Damon2 self-ligating bracket (SDS Ormco, Orange, Calif) and a conventional mini-twin bracket (Orthos, SDS Ormco). The relative effects of various wire sizes and materials on ligation times were investigated. The study was carried out by 1 operator experienced in the use of self-ligating and conventional brackets. The Damon2 self-ligating system had a significantly shorter mean archwire ligation time for both placing (P <.001) and removing (P <.01) wires compared with the conventional elastomeric system. Ligation of an archwire was approximately twice as quick with the self-ligating system. Opening a Damon slide was on average 1 second quicker per bracket than removing an elastic from the mini-twin brackets, and closing a slide was 2 seconds faster per bracket. This difference in ligation time between the Damon2 and the conventional mini-twin brackets became more marked for larger wire sizes used in later treatment stages. The type of bracket and the size of wire used are statistically significant predictors for speed of ligation and chairside time. The self-ligating system offered quicker and arguably more efficient wire removal and placement for most orthodontic treatment stages.
Kao, Chia-Tze; Ding, Shinn-Jyh; Chen, Yu-Chih; Huang, Tsui-Hsien
2002-01-01
Typically, an orthodontic metal bracket is made from stainless steel. It has been shown that such metal may corrode in an acid- and chloride-rich environment. The purpose of the current study was to investigate a titanium nitride (TiN) ion-plated stainless steel orthodontic bracket's anticorrosion properties and compare its biocompatibility with that of non-TiN-plated brackets. The stainless-steel brackets studied here were tested in acidic artificial saliva. The plated metal bracket was produced by the titanium nitride (TiN) ion-plating method. The TiN-plating on the bracket surface was demonstrated to be successful by EDX analysis. The quantity of metallic-ion release under test immersion solutions was analyzed by atomic absorption spectrophotometry. Both TiN- and non-TiN-plated brackets may release detectable ions into the test solution, including nickel, chromium, manganese, copper, and iron (ferric). The anticorrosion ability of the plated bracket was analyzed by means of inductively coupled plasma atomic emission spectroscopy. The results revealed that the TiN-plated metal bracket did not increase the anticorrosion ability of the standard bracket. The biocompatibility of the TiN plating versus the standard bracket material resulting from bracket immersion in the test solution revealed no toxicity on U2OS cells using a methylthiazole tetrazolium (MTT) colorimetric assay. Clearly, the search for an improved technique for enhancing the anticorrosion ability of the normal metal orthodontic bracket should be continued. Copyright 2002 Wiley Periodicals, Inc.
A Non-technical User-Oriented Display Notation for XACML Conditions
NASA Astrophysics Data System (ADS)
Stepien, Bernard; Felty, Amy; Matwin, Stan
Ideally, access control to resources in complex IT systems ought to be handled by business decision makers who own a given resource (e.g., the pay and benefits section of an organization should decide and manage the access rules to the payroll system). To make this happen, the security and database communities need to develop vendor-independent access management tools, useable by decision makers, rather than technical personnel detached from a given business function. We have developed and implemented such tool, based on XACML. The XACML is an important emerging tool for managing complex access control applications. As a formal notation, based on an XML schema representing the grammar of a given application, XACML is precise and non-ambiguous. But this very property puts it out of reach of non-technical users. We propose a new notation for displaying and editing XACML rules that is independent of XML, and we develop an editor for it. Our notation combines a tree representation of logical expressions with an accessible natural language layer. Our early experience indicates that such rules can be grasped by non-technical users wishing to develop and control rules for accessing their own resources.
Rojo, Marcial García; Rolón, Elvira; Calahorra, Luis; García, Felix Oscar; Sánchez, Rosario Paloma; Ruiz, Francisco; Ballester, Nieves; Armenteros, María; Rodríguez, Teresa; Espartero, Rafael Martín
2008-07-15
Process orientation is one of the essential elements of quality management systems, including those in use in healthcare. Business processes in hospitals are very complex and variable. BPMN (Business Process Modelling Notation) is a user-oriented language specifically designed for the modelling of business (organizational) processes. Previous experiences of the use of this notation in the processes modelling within the Pathology in Spain or another country are not known. We present our experience in the elaboration of the conceptual models of Pathology processes, as part of a global programmed surgical patient process, using BPMN. With the objective of analyzing the use of BPMN notation in real cases, a multidisciplinary work group was created, including software engineers from the Dep. of Technologies and Information Systems from the University of Castilla-La Mancha and health professionals and administrative staff from the Hospital General de Ciudad Real. The work in collaboration was carried out in six phases: informative meetings, intensive training, process selection, definition of the work method, process describing by hospital experts, and process modelling. The modelling of the processes of Anatomic Pathology is presented using BPMN. The presented subprocesses are those corresponding to the surgical pathology examination of the samples coming from operating theatre, including the planning and realization of frozen studies. The modelling of Anatomic Pathology subprocesses has allowed the creation of an understandable graphical model, where management and improvements are more easily implemented by health professionals.
Kurata, Hiroyuki; Inoue, Kentaro; Maeda, Kazuhiro; Masaki, Koichi; Shimokawa, Yuki; Zhao, Quanyu
2007-01-01
Biochemical network maps are helpful for understanding the mechanism of how a collection of biochemical reactions generate particular functions within a cell. We developed a new and computationally feasible notation that enables drawing a wide resolution map from the domain-level reactions to phenomenological events and implemented it as the extended GUI network constructor of CADLIVE (Computer-Aided Design of LIVing systEms). The new notation presents ‘Domain expansion’ for proteins and RNAs, ‘Virtual reaction and nodes’ that are responsible for illustrating domain-based interaction and ‘InnerLink’ that links real complex nodes to virtual nodes to illustrate the exact components of the real complex. A modular box is also presented that packs related reactions as a module or a subnetwork, which gives CADLIVE a capability to draw biochemical maps in a hierarchical modular architecture. Furthermore, we developed a pathway search module for virtual knockout mutants as a built-in application of CADLIVE. This module analyzes gene function in the same way as molecular genetics, which simulates a change in mutant phenotypes or confirms the validity of the network map. The extended CADLIVE with the newly proposed notation is demonstrated to be feasible for computational simulation and analysis. PMID:17940089
Rojo, Marcial García; Rolón, Elvira; Calahorra, Luis; García, Felix Óscar; Sánchez, Rosario Paloma; Ruiz, Francisco; Ballester, Nieves; Armenteros, María; Rodríguez, Teresa; Espartero, Rafael Martín
2008-01-01
Background Process orientation is one of the essential elements of quality management systems, including those in use in healthcare. Business processes in hospitals are very complex and variable. BPMN (Business Process Modelling Notation) is a user-oriented language specifically designed for the modelling of business (organizational) processes. Previous experiences of the use of this notation in the processes modelling within the Pathology in Spain or another country are not known. We present our experience in the elaboration of the conceptual models of Pathology processes, as part of a global programmed surgical patient process, using BPMN. Methods With the objective of analyzing the use of BPMN notation in real cases, a multidisciplinary work group was created, including software engineers from the Dep. of Technologies and Information Systems from the University of Castilla-La Mancha and health professionals and administrative staff from the Hospital General de Ciudad Real. The work in collaboration was carried out in six phases: informative meetings, intensive training, process selection, definition of the work method, process describing by hospital experts, and process modelling. Results The modelling of the processes of Anatomic Pathology is presented using BPMN. The presented subprocesses are those corresponding to the surgical pathology examination of the samples coming from operating theatre, including the planning and realization of frozen studies. Conclusion The modelling of Anatomic Pathology subprocesses has allowed the creation of an understandable graphical model, where management and improvements are more easily implemented by health professionals. PMID:18673511
In vivo effectiveness of enamel sealants around orthodontic brackets.
Bechtold, T E; Sobiegalla, A; Markovic, M; Berneburg, M; Göz, G R
2013-11-01
In this randomized study, the caries-protective effect on vestibular enamel of two fluoride-containing sealants (Protecto® and Light Bond®) during multibracket treatment was investigated. In all, 40 orthodontic patients about to receive a multibracket appliance with the brackets bonded to the vestibular tooth surfaces were randomly included in this study. Each one was randomly assigned to one of four groups. A crossover design was selected in which a sealed quadrant was contralateral to an unsealed quadrant, then choosing the reverse configuration in the opposite jaw. Two sealants were, thus, tested on vestibular enamel on left and right anterior teeth and premolars in both jaws of each patient over 6 months of multibracket treatment. A DIAGNOdent® pen measuring laser fluorescence was used to analyze the relevant enamel surfaces both at baseline and after 6 months. Neither the incidence nor the characteristics of the demineralization we observed during the study differed between the 4 groups. Single application of smooth-surface sealants did not protect enamel around brackets from incipient carious lesions during the first 6 months of multibracket treatment.
Electrical servo actuator bracket. [fuel control valves on jet engines
NASA Technical Reports Server (NTRS)
Sawyer, R. V. (Inventor)
1981-01-01
An electrical servo actuator is mounted on a support arm which is allowed to pivot on a bolt through a fixed mounting bracket. The actuator is pivotally connected to the end of the support arm by a bolt which has an extension allowed to pass through a slot in the fixed mounting bracket. An actuator rod extends from the servo actuator to a crank arm which turns a control shaft. A short linear thrust of the rod pivots the crank arm through about 90 for full-on control with the rod contracted into the servo actuator, and full-off control when the rod is extended from the actuator. A spring moves the servo actuator and actuator rod toward the control crank arm once the actuator rod is fully extended in the full-off position. This assures the turning of the control shaft to a full-off position. A stop bolt and slot are provided to limit pivot motion. Once fully extended, the spring pivots the motion.
21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.
Code of Federal Regulations, 2012 CFR
2012-04-01
... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Bracket adhesive resin and tooth conditioner. 872... and tooth conditioner. (a) Identification. A bracket adhesive resin and tooth conditioner is a device... to a tooth surface. (b) Classification. Class II....
21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.
Code of Federal Regulations, 2010 CFR
2010-04-01
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bracket adhesive resin and tooth conditioner. 872... and tooth conditioner. (a) Identification. A bracket adhesive resin and tooth conditioner is a device... to a tooth surface. (b) Classification. Class II....
21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.
Code of Federal Regulations, 2011 CFR
2011-04-01
... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Bracket adhesive resin and tooth conditioner. 872... and tooth conditioner. (a) Identification. A bracket adhesive resin and tooth conditioner is a device... to a tooth surface. (b) Classification. Class II....
21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.
Code of Federal Regulations, 2014 CFR
2014-04-01
... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Bracket adhesive resin and tooth conditioner. 872... and tooth conditioner. (a) Identification. A bracket adhesive resin and tooth conditioner is a device... to a tooth surface. (b) Classification. Class II....
21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.
Code of Federal Regulations, 2013 CFR
2013-04-01
... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Bracket adhesive resin and tooth conditioner. 872... and tooth conditioner. (a) Identification. A bracket adhesive resin and tooth conditioner is a device... to a tooth surface. (b) Classification. Class II....
Friction forces during sliding of various brackets for malaligned teeth: an in vitro study.
Crincoli, Vito; Perillo, Letizia; Di Bisceglie, Maria Beatrice; Balsamo, Antonio; Serpico, Vitaliano; Chiatante, Francesco; Pappalettere, Carmine; Boccaccio, Antonio
2013-01-01
To measure the friction force generated during sliding mechanics with conventional, self-ligating (Damon 3 mx, Smart Clip, and Time 3) and low-friction (Synergy) brackets using different archwire diameters and ligating systems in the presence of apical and buccal malalignments of the canine. An experimental setup reproducing the right buccal segment of the maxillary arch was designed to measure the friction force generated at the bracket/wire and wire/ligature interfaces of different brackets. A complete factorial plan was drawn up and a three-way analysis of variance (ANOVA) was carried out to investigate whether the following factors affect the values of friction force: (i) degree of malalignment, (ii) diameter of the orthodontic wire, and (iii) bracket/ligature combination. Tukey post hoc test was also conducted to evaluate any statistically significant differences between the bracket/ligature combinations analyzed. ANOVA showed that all the above factors affect the friction force values. The friction force released during sliding mechanics with conventional brackets is about 5-6times higher than that released with the other investigated brackets. A quasilinear increase of the frictional forces was observed for increasing amounts of apical and buccal malalignments. The Synergy bracket with silicone ligature placed around the inner tie-wings appears to yield the best performance.
Friction Forces during Sliding of Various Brackets for Malaligned Teeth: An In Vitro Study
Crincoli, Vito; Di Bisceglie, Maria Beatrice; Balsamo, Antonio; Serpico, Vitaliano; Chiatante, Francesco; Pappalettere, Carmine; Boccaccio, Antonio
2013-01-01
Aims. To measure the friction force generated during sliding mechanics with conventional, self-ligating (Damon 3 mx, Smart Clip, and Time 3) and low-friction (Synergy) brackets using different archwire diameters and ligating systems in the presence of apical and buccal malalignments of the canine. Methods. An experimental setup reproducing the right buccal segment of the maxillary arch was designed to measure the friction force generated at the bracket/wire and wire/ligature interfaces of different brackets. A complete factorial plan was drawn up and a three-way analysis of variance (ANOVA) was carried out to investigate whether the following factors affect the values of friction force: (i) degree of malalignment, (ii) diameter of the orthodontic wire, and (iii) bracket/ligature combination. Tukey post hoc test was also conducted to evaluate any statistically significant differences between the bracket/ligature combinations analyzed. Results. ANOVA showed that all the above factors affect the friction force values. The friction force released during sliding mechanics with conventional brackets is about 5-6times higher than that released with the other investigated brackets. A quasilinear increase of the frictional forces was observed for increasing amounts of apical and buccal malalignments. Conclusion. The Synergy bracket with silicone ligature placed around the inner tie-wings appears to yield the best performance. PMID:23533364
Influence of Tm:YAP laser irradiation on tensile strength for bracket debonding
NASA Astrophysics Data System (ADS)
Dostalova, Tatjana; Jelinkova, Helena; Sulc, Jan; Koranda, Petr; Nemec, Michal; Fibrich, Martin; Jelinek, Michal; Michalik, Pavel; Miyagi, Mitsunobu
2011-03-01
The investigation of tensile strength needed for bracket debonding was the aim of study. A diode pumped Tm: YAP microchip laser generating a continuous 2um radiation with the maximum output power of 4W was used for debonding purposes. The group of 60 brackets was debonded using classical and laser irradiation methods - the doze from 1W to 4 W, 60s. The tensile strength without laser irradiation was in the range from 39.6 N (full ceramic bracket group) to 63.7 N (ceramic bracket with metal slot group). After irradiation the tensile strength was decreased from 35.1 N (full ceramic bracket group) to 48.8 N (ceramic bracket with metal slot group). The results of our study generally agree with the previous studies, substantiating the fact that lasers can be used effectively to thermally soften the adhesive resin for removal of ceramic brackets. From the practical point of view is conclusion that during laser irradiation, thermal ablation occurs and the bracket is removed from the enamel together with the rest of the adhesive resin. Laser debonding is easier and little heat diffusion occurred.
Ciocan, Delia Ioana; Stanciu, Dragoş; Popescu, Manuela Anca; Miculescu, Florin; Plotog, Ioan; Vărzaru, Gaudenţiu; Ciocan, Lucian Toma
2014-01-01
This study proposed to evaluate the surface morphology of different types of orthodontic brackets and the characteristics of their adhesion to the tooth enamel. There have been taken into study six metallic, five ceramic and one polymeric bracket from different brands (Ormco, Lancer, Leone, Damon, 3M, Ultradent, American Orthodontics, Rocky Mountain). The surface base of the each bracket it have been ESEM analyzed using scanning electron microscope Phillips XL-30 ESEM. There have been investigated several parameters that have a potential influence of the bracket-bonding agent interface joint: chemical composition, roughness, surface morphology and wideness. After ESEM analysis, the same metallic and ceramic brackets have been afterwards collated on extracted teeth and subjected to mechanical tests. After the mechanical testing, the samples were once again ESEM investigated. All fractures occurred in the area of the adhesive system, recording adhesive fractures of the tooth-composite resin and composite-bracket, cohesive fractures and both. The metallic brackets surfaces that are optima for a good adhesion is that of a mesh sand blasted and acid etched. From the esthetic brackets, the ceramic ones are superior to polymeric ones regarding bonding to teeth.
Folco, Alejandra A; Benítez-Rogé, Sandra C; Iglesias, Marina; Calabrese, Diana; Pelizardi, Cristina; Rosa, Alcira; Brusca, Marisa I; Hecht, Pedro; Mateu, María E
2014-01-01
Orthodontic brackets contribute to the accumulation of bacterial plaque on tooth surfaces because they hinder oral hygiene. In contrast to conventional brackets, self-ligating brackets do not require additional parts to support the arches, thus improving dental hygiene. The aim of this study was to compare the gingival response in orthodontic patients wearing self-ligating or conventional brackets. A sample of 22 patients aged 16 to 30 years was divided into two groups: Group A, treated with selfligating brackets (Damon system) and Group B, treated with conventional brackets (Roth technique). The following were assessed during the treatment: Plaque Index (PI), Gingival Index (GI) and Probing Depth (PD), and sub-gingival samples were taken from teeth 14/24 for microbiological observation. No statistically significant difference was found between Groups A and B; p>0.05 (sign-ranked) or between PI, GI and PD at the different times (Friedman's Analysis of Variance), even though the indices were found to increase at 14 days, particularly for self-ligating brackets. The quantity and quality of microorganisms present were compatible with health on days 0, 28 and 56. As from day 14 there is a predominance of microbiota compatible with gingivitis in both groups. In the samples studied, orthodontic treatment increases bacterial plaque and inflammatory gingival response, but gingival-periodontal health can be maintained with adequate basic therapy. Self-ligating and conventional brackets produced similar gingival response.
Effect of fluoride solutions on the structure and hardness of plastic brackets.
Tziafa, Christina; Zinelis, Spiros; Makou, Margarita; Eliades, Theodore; Eliades, George
2010-01-01
To investigate the surface morphology, structure, molecular and elemental composition, and hardness of plastic brackets exposed to fluoride solutions. Two types of plastic brackets (Silkon Plus and SpiritMB) were exposed to three fluoride solutions 10 times for 1 minute each and then subjected to attenuated total relectance-Fournier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy (SEM), x-ray energy dispersive microanalysis (EDS), and Vickers hardness (HV) testing. Hardness data were analyzed via two-way ANOVA and Tukey tests at the .05 level of significance with brackets and fluoride solution as predictors. ATR-FTIR spectroscopy showed that both bracket types consisted of polycarbonate. After treatment with acidulated phosphate fluoride, an increased contribution of -OH peaks at 3,200 cm-1(stretching [str]) and 1,640 cm-1 (a type of vibration [b]) was observed in both brackets. SEM revealed that the acidulated phosphate fluoride solution had a strong effect on the morphology and surface structure of the two brackets; a general deterioration with projections of the reinforcing fibers was observed. EDS showed evidence of aluminum, calcium, silicon, magnesium, and titanium, which could be attributed to the reinforcing glass fiber constituents. Hardness ranged in the order of 20 HV with no difference among the two bracket types and the three fluoride exposures. Repeated exposure of plastic brackets to fluoride solutions has a pronounced effect on their structure and morphology, but not their hardness. © 2010 BY QUINTESSENCE PUBLISHING CO, INC.
Algebraic construction of a Nambu bracket for the two-dimensional vorticity equation.
Sommer, M; Brazda, K; Hantel, M
2011-08-29
So far fluid mechanical Nambu brackets have mainly been given on an intuitive basis. Alternatively an algorithmic construction of such a bracket for the two-dimensional vorticity equation is presented here. Starting from the Lie-Poisson form and its algebraic properties it is shown how the Nambu representation can be explicitly constructed as the continuum limit from the structure preserving Zeitlin discretization.
Liu, Xiaomo; Lin, Jiuxiang; Ding, Peng
2013-01-01
In this study, we tested the surface roughness of bracket slots and the friction coefficient between the bracket and the stainless steel archwire before and after orthodontic treatment. There were four experimental groups: groups 1 and 2 were 3M new and retrieved brackets, respectively, and groups 3 and 4 were BioQuick new and retrieved brackets, respectively. All retrieved brackets were taken from patients with the first premolar extraction and using sliding mechanics to close the extraction space. The surface roughness of specimens was evaluated using an optical interferometry profilometer, which is faster and nondestructive compared with a stylus profilometer, and provided a larger field, needing no sample preparation, compared with atomic force microscopy. Orthodontic treatment resulted in significant increases in surface roughness and coefficient of friction for both brands of brackets. However, there was no significant difference by brand for new or retrieved brackets. These retrieval analysis results highlight the necessity of reevaluating the properties and clinical behavior of brackets during treatment to make appropriate treatment decisions. © Wiley Periodicals, Inc.
Jithesh, C.; Venkataramana, V.; Penumatsa, Narendravarma; Reddy, S. N.; Poornima, K. Y.; Rajasigamani, K.
2015-01-01
Objectives: To determine and compare the potential difference of nickel release from three different orthodontic brackets, in different artificial pH, in different time intervals. Materials and Methods: Twenty-seven samples of three different orthodontic brackets were selected and grouped as 1, 2, and 3. Each group was divided into three subgroups depending on the type of orthodontic brackets, salivary pH and the time interval. The Nickel release from each subgroup were analyzed by using inductively coupled plasma-Atomic Emission Spectrophotometer (Perkin Elmer, Optima 2100 DV, USA) model. Quantitative analysis of nickel was performed three times, and the mean value was used as result. ANOVA (F-test) was used to test the significant difference among the groups at 0.05 level of significance (P < 0.05). The descriptive method of statistics was used to calculate the mean, standard deviation, minimum and maximum. SPSS 18 software ((SPSS.Ltd, Quarry bay, Hong Kong, PASW-statistics 18) was used to analyze the study. Result: The analysis shows a significant difference between three groups. The study shows that the nickel releases from the recycled stainless steel brackets have the highest at all 4.2 pH except in 120 h. Conclusion: The study result shows that the nickel release from the recycled stainless steel brackets is highest. Metal slot ceramic bracket release significantly less nickel. So, recycled stainless steel brackets should not be used for nickel allergic patients. Metal slot ceramic brackets are advisable. PMID:26538924
The tensile bond strength of new and rebonded stainless steel orthodontic brackets.
Regan, D; LeMasney, B; van Noort, R
1993-04-01
The study investigated the effect on the tensile/peel bond strength of the variables associated with the bracket base, the enamel surface, and the type of adhesive when both new and used brackets were rebonded to a previously bonded enamel surface. The tensile/peel bond strength was firstly evaluated for three different types of stainless steel orthodontic bracket/base combinations. The cast integral base gave a significantly lower bond strength than the foil-mesh and photo-etched bases. Following debonding, a group of new brackets were bonded to the teeth using a chemically-activated or a light-cured adhesive. The old adhesive had been removed from the enamel by either a hand scaler or a tungsten-carbide bur. The rebonded new brackets demonstrated a small, but statistically significant fall in bond strength. No differences were found between the enamel preparations or the adhesives. A further group of previously debonded brackets were rebonded to the same teeth. The bracket bases were prepared by either smoothing with a green stone or heating in a bunsen flame followed by sandblasting and electropolishing. Highly significant falls in bond strength were obtained with all the bases. No significant differences were found between the two methods of bracket preparation.
Microleakage under ceramic flash-free orthodontic brackets after thermal cycling.
Kim, Julia; Kanavakis, Georgios; Finkelman, Matthew D; Lee, Moonyoung
2016-11-01
To compare microleakage under 3M Unitek's APC Flash-Free Adhesive Coated System bracket and the APC PLUS Adhesive Coated System bracket after thermal cycling. Forty freshly extracted human maxillary premolars were randomly divided into two groups and bonded with either a Flash-Free bracket or a PLUS bracket. After bonding, the samples were incubated in a water bath at 37°C for 24 hours and thermocycled for 5000 cycles between 5°C and 50°C. All teeth were immersed in a 2% methylene blue solution for 24 hours, embedded in acrylic and sectioned in a buccolingual direction at approximately the center of the bracket. Microleakage was observed at the enamel-adhesive interface from the occlusal and gingival margins of the bracket base. Statistical analysis was conducted using the Mann-Whitney U-test. The median microleakage was higher in the Flash-Free group, but the difference between the two groups was not statistically significant (P > .05). In a laboratory setting, there is no significant difference between the extent of microleakage under the APC Flash-Free Adhesive Coated System bracket and the APC PLUS Adhesive Coated System bracket after thermal cycling.
Rozak, David A; Rozak, Anthony J
2014-01-22
Ambiscript is a graphically-designed nucleic acid notation that uses symbol symmetries to support sequence complementation, highlight biologically-relevant palindromes, and facilitate the analysis of consensus sequences. Although the original Ambiscript notation was designed to easily represent consensus sequences for multiple sequence alignments, the notation's black-on-white ambiguity characters are unable to reflect the statistical distribution of nucleotides found at each position. We now propose a color-augmented ambigraphic notation to encode the frequency of positional polymorphisms in these consensus sequences. We have implemented this color-coding approach by creating an Adobe Flash® application ( http://www.ambiscript.org) that shades and colors modified Ambiscript characters according to the prevalence of the encoded nucleotide at each position in the alignment. The resulting graphic helps viewers perceive biologically-relevant patterns in multiple sequence alignments by uniquely combining color, shading, and character symmetries to highlight palindromes and inverted repeats in conserved DNA motifs. Juxtaposing an intuitive color scheme over the deliberate character symmetries of an ambigraphic nucleic acid notation yields a highly-functional nucleic acid notation that maximizes information content and successfully embodies key principles of graphic excellence put forth by the statistician and graphic design theorist, Edward Tufte.
An investigation into the use of the FDI tooth notation system by dental schools in the UK.
Blinkhorn, A S; Choi, C L; Paget, H E
1998-02-01
This study investigated the use of the FDI tooth notation system in UK dental schools. In addition, the notation system used by dentists referring patients to Manchester Dental Hospital was recorded. A questionnaire was sent to the Deans of all Dental Schools in the UK and letters of referral to Manchester Dental Hospitals Paediatric GA Service were monitored for 1 month. The results showed that only Manchester University Dental School used the FDI system but 6 other schools instructed students in its use. The Palmer system was used by all the other schools for recording clinical information. 136 referral letters were received, only one used the FDI notation, 15 used both FDI and Palmer and the remainder (120) requested extractions using the Palmer notation. The FDI notation system is not used in the majority of UK dental schools. Despite the fact the Dental School in Manchester has been teaching and using the FDI system for over 10 years, it has not been adopted by General Dental Practitioners referring patients into the hospital. The FDI should review the use of their system in other countries, to ascertain whether it has fulfilled its role as an international notation system.
Nd:YAG Laser-aided ceramic brackets debonding: Effects on shear bond strength and enamel surface
NASA Astrophysics Data System (ADS)
Han, Xianglong; Liu, Xiaolin; Bai, Ding; Meng, Yao; Huang, Lan
2008-11-01
In order to evaluate the efficiency of Nd:YAG laser-aided ceramic brackets debonding technique, both ceramic brackets and metallic brackets were bonded with orthodontic adhesive to 30 freshly extracted premolars. The specimens were divided into three groups, 10 in each, according to the brackets employed and the debonding techniques used: (1) metallic brackets with shear debonding force, (2) ceramic brackets with shear debonding force, and (3) ceramic brackets with Nd:YAG laser irradiation. The result showed that laser irradiation could diminish shear bond strength (SBS) significantly and produce the most desired ARI scores. Moreover, scanning electron microscopy investigation displayed that laser-aided technique induced little enamel scratch or loss. It was concluded that Nd:YAG laser could facilitate the debonding of ceramic brackets and diminish the amount of remnant adhesive without damaging enamel structure.
A three-year clinical trial using a glass ionomer cement for the bonding of orthodontic brackets.
Miller, J R; Mancl, L; Arbuckle, G; Baldwin, J; Phillips, R W
1996-01-01
Recent clinical studies measuring orthodontic bracket failure, when using glass ionomer cement as an adhesive, have reported a wide range of percentages of bracket failure. The present study recorded bracket failure over a 3-year period, longer than had been previously measured. Seventeen participants were randomly assigned to one of two treatment groups, either using glass ionomer cement or composite resin for bonding. In each group, brackets were bonded to incisors, canines, and premolars. Bracket failure was measured over the duration of comprehensive orthodontic treatment for all participants. Brackets bonded with the glass ionomer cement were more likely to fail (log-rank test; P < or = 0.022). This difference was clinically significant. At the present time, the disadvantage of extra bracket failures appears to outweigh potential advantages when considering glass ionomer cement for the routine bonding of orthodontic brackets.
Berger, Sandrine Bittencourt; Guiraldo, Ricardo Danil; Lopes, Murilo Baena; Oltramari-Navarro, Paula Vanessa; Fernandes, Thais Maria; Schwertner, Renata de Castro Alves; Ursi, Wagner José Silva
2016-01-01
The application of bleaching agents before placement of resin-bonded fixed appliances significantly, but temporarily, reduces bond strength to tooth structure. Antioxidants have been studied as a means to remove residual oxygen that compromises bonding to bleached enamel. This in vitro study evaluated whether green tea (GT) could restore the shear bond strength between bonded orthodontic brackets and bleached enamel. Six experimental groups were compared: group 1, no bleaching plus bracket bonding (positive control); group 2, bleaching with 35% hydrogen peroxide (HP) plus bracket bonding (negative control); group 3, 35% HP plus 10% sodium ascorbate (SA) plus bracket bonding; group 4, 35% HP plus 10% GT plus bracket bonding; group 5, no bleaching plus 10% SA plus bracket bonding; group 6, no bleaching plus 10% GT plus bracket bonding. Results suggested that GT, like SA, may be beneficial for bracket bonding immediately after bleaching.
NASA Astrophysics Data System (ADS)
Sinescu, Cosmin; Negrutiu, Meda L.; Hughes, Michael; Bradu, Adrian; Todea, Carmen; Rominu, Roxana; Dodenciu, Dorin; Laissue, Philippe L.; Podoleanu, Adrian G.
2008-04-01
Despite good diagnosis and treatment planning, orthodontic treatment can fail if bonding fails. It is now common practice to address the aesthetic appearance of patients using aesthetic brackets instead of metal ones. Therefore, bonding aesthetic brackets has become an issue for orthodontists today. Orthodontic bonding is mainly achieved using composite resin but can also be performed with glass ionomer or resin cements. For improving the quality of bonding, the enamel is acid etched for 30 seconds with 38% phosphoric acid and then a bonding agent is applied. In our study we investigated and compared the quality of bonding between ceramic brackets, polymeric brackets and enamel, respectively using a new investigation method-OCT. The aim of our study was to evaluate the resin layer at the bracket base-tooth interface.
Effect of eliminating the residual fluoride gel on titanium bracket corrosion.
Khoury, Elie S; Abboud, Maher; Bassil-Nassif, Nayla; Bouserhal, Joseph
2011-09-01
Fluoride ions, in long-term applications on titanium brackets, cause their corrosion. Fluoride gel used for caries prevention during orthodontic treatment has a very high concentration in fluoride ions, and therefore has the potential for causing bracket corrosion. The main aim of this study was to determine the effect of eliminating the residual fluoride gel, by rinsing it, on the corrosion of titanium brackets. The secondary aim was to evaluate the corrosion of titanium brackets in the presence of fluoride gel. One hundred titanium brackets were divided into five groups of 20 brackets each. Group 1 being the control group, the rest of the groups were immersed in fluoride gel: Group 2 for 4 minutes and kept for 30 minutes with the residual fluoride gel on; Group 3 for 4 minutes followed by immediate water rinsing; Group 4 for 12 minutes and kept for 90 minutes with the residual fluoride gel on and Group 5 for 12 minutes followed by immediate water rinsing. All groups were rinsed then dried, for 20 hours, using Silica gel in a desiccator maintained at 37°C before testing. Gravimetrical results and SEM analysis showed no significant difference between Groups 2, 3 and 5 compared to each other and to the control group. Only Group 4 showed significant weight loss and pitting corrosion in four of the 20 brackets. In sliding resistance, no significant difference was detected between any of the groups. Short time applications of fluoride gel do not affect sliding resistance of titanium brackets. No titanium corrosion was detected for one application of concentrated fluoride gel and some brackets showed pitting corrosion for three applications. The rinsing of residual fluoride gel eliminates completely the risk of bracket corrosion. Copyright © 2011 CEO. Published by Elsevier Masson SAS. All rights reserved.
Physical and chemical properties of orthodontic brackets after 12 and 24 months: in situ study
MENDES, Bernardo de Azevedo Bahia; FERREIRA, Ricardo Alberto Neto; PITHON, Matheus Melo; HORTA, Martinho Campolina Rebello; OLIVEIRA, Dauro Douglas
2014-01-01
Objective The aim of this article was to assess how intraoral biodegradation influenced the surface characteristics and friction levels of metallic brackets used during 12 and 24 months of orthodontic treatment and also to compare the static friction generated in these brackets with four different methods of the ligation of orthodontic wires. Material and Methods Seventy premolar brackets as received from the manufacturer and 224 brackets that were used in previous orthodontic treatments were evaluated in this experiment. The surface morphology and the composition of the deposits found in the brackets were evaluated with rugosimetry, scanning electron microscopy, and energy dispersive X-ray spectroscopy. Friction was analyzed by applying tensile tests simulating sliding mechanics with a 0.019x0.025" steel wire. The static friction levels produced by the following ligation methods were evaluated: loosely attached steel ligature around all four bracket wings, steel ligature attached to only two wings, conventional elastomeric ligation around all 4 bracket wings, and non-conventional Slide® elastomeric ligature. Results The results demonstrated the presence of biodegradation effects such as corrosion pits, plastic deformation, cracks, and material deposits. The main chemical elements found on these deposits were Carbon and Oxygen. The maximum friction produced by each ligation method changed according to the time of intraoral use. The steel ligature loosely attached to all four bracket wings produced the lowest friction levels in the new brackets. The conventional elastic ligatures generated the highest friction levels. The metallic brackets underwent significant degradation during orthodontic treatment, showing an increase in surface roughness and the deposit of chemical elements on the surface. Conclusion The levels of static friction decreased with use. The non-conventional elastic ligatures were the best alternative to reduce friction. PMID:25025560
Kommi, Pradeep Babu; Kumar, M Senthil; Hanumanth; Venkatesan; Aniruddh; Arvinth; Kumar, Arani Nanda
2016-01-01
Introduction Most of the patients seek orthodontic treatment to improve the smile, which improves the facial profile by means of fixed appliances i.e., brackets and wires. The brackets are of different types like stainless steel and ceramic. Ceramic brackets were considered as aesthetic appliance which was divided into mono-crystalline, polycrystalline and sapphire brackets. The light transmittance might influence the degree of curing adhesive material in mono crystalline, polycrystalline and sapphire brackets. Aim The aim of the present study was to evaluate the translucency and intensity of three different aesthetic brackets (mono crystalline, poly crystalline and sapphire ceramic brackets) and to determine their influence on shear bond strength of the brackets. The adhesive remnant index was also measured after debonding of the brackets from the tooth surface. Materials and Methods Twenty six samples each of monocrystalline, polycrystalline and sapphire brackets (total 78 ceramic brackets) were used for the study. The bracket samples were subjected to optical fluorescence test using spectrofluorometer to measure the intensity of the brackets. Seventy eight extracted premolar teeth were procured and divided into 3 groups. The brackets were then bonded to the tooth using Transbond XT (3M Unitek) light cure composite material and cured with new light cure unit (Light Emitting Diode) of wood pecker company (400-450nm) for 30 seconds, and these samples were subjected to shear bond strength test with Instron Universal Testing Machine (UNITEK-94100) with a load range between 0 to 100 KN with a maximum cross head speed of 0.5mm/min. ARI (Adhesive Remnant Index) scores were evaluated according to Artun and Bergland scoring system using stereomicroscope at 20x magnification. Results The light absorption values obtained from spectrofluorometeric study were 3300000–3500000 cps for group 1 (monocrystalline ceramic brackets), 6000000–6500000 cps for Group 2
Mohamed, Jauhar P; Kommi, Pradeep Babu; Kumar, M Senthil; Hanumanth; Venkatesan; Aniruddh; Arvinth; Kumar, Arani Nanda
2016-08-01
Most of the patients seek orthodontic treatment to improve the smile, which improves the facial profile by means of fixed appliances i.e., brackets and wires. The brackets are of different types like stainless steel and ceramic. Ceramic brackets were considered as aesthetic appliance which was divided into mono-crystalline, polycrystalline and sapphire brackets. The light transmittance might influence the degree of curing adhesive material in mono crystalline, polycrystalline and sapphire brackets. The aim of the present study was to evaluate the translucency and intensity of three different aesthetic brackets (mono crystalline, poly crystalline and sapphire ceramic brackets) and to determine their influence on shear bond strength of the brackets. The adhesive remnant index was also measured after debonding of the brackets from the tooth surface. Twenty six samples each of monocrystalline, polycrystalline and sapphire brackets (total 78 ceramic brackets) were used for the study. The bracket samples were subjected to optical fluorescence test using spectrofluorometer to measure the intensity of the brackets. Seventy eight extracted premolar teeth were procured and divided into 3 groups. The brackets were then bonded to the tooth using Transbond XT (3M Unitek) light cure composite material and cured with new light cure unit (Light Emitting Diode) of wood pecker company (400-450nm) for 30 seconds, and these samples were subjected to shear bond strength test with Instron Universal Testing Machine (UNITEK-94100) with a load range between 0 to 100 KN with a maximum cross head speed of 0.5mm/min. ARI (Adhesive Remnant Index) scores were evaluated according to Artun and Bergland scoring system using stereomicroscope at 20x magnification. The light absorption values obtained from spectrofluorometeric study were 3300000-3500000 cps for group 1 (monocrystalline ceramic brackets), 6000000-6500000 cps for Group 2 (polycrystalline ceramic brackets) and 2700000 -3000000 cps for
New infinite-dimensional algebras, sine brackets, and SU (infinity)
Zachos, C.K.; Fairlie, D.B.
1989-01-01
We investigate the infinite dimensional algebras we have previously introduced, which involve trigonometric functions in their structure constants. We find a realization for them which provides a basis-independent formulation, identified with the algebra of sine brackets. A special family of them, the cyclotomic ones, contain SU(N) as invariant subalgebras. In this basis, it is evident by inspection that the algebra of SU(infinity) is equivalent to the centerless algebra of SDiff/sub 0/ on two-dimensional manifolds. Gauge theories of SU(infinity) are thus simply reformulated in terms of surface (sheet) coordinates. Spacetime-independent configurations of their gauge fields describe strings through the quadratic Schild action. 11 refs.
Correction of palatally displaced maxillary lateral incisors without brackets
Choi, Kyung-Hee; Lee, Yoonjung; Kim, Minji
2013-01-01
This article describes the orthodontic treatment of a 25-year-old Korean female patient with anterior crowding, including palatally displaced lateral incisors. Her facial profile was satisfactory, but 3.5 mm of maxillary anterior crowding was observed. To correct this crowding, we decided to minimize the use of the conventional fixed orthodontic appliances and employed a less bulky and more aesthetic appliance for applying light continuous force. We determined the final positions of the maxillary teeth via a working model for diagnostic set up and achieved space gaining and alignment with simple Ni-Ti spring and stainless steel round tubes. Tooth alignment was achieved efficiently and aesthetically without the conventional brackets. PMID:24015390
Bleaching effects on shear bond strengths of orthodontic brackets.
Martins, Mariana M; de Oliveira Almeida, Marco A; Elias, Carlos N; de Moraes Mendes, Alvaro
2012-05-01
The purpose of this research was to investigate the influence of 35% hydrogen peroxide on orthodontic bracket adhesion at zero hour, 24 hours, 7, 21 and 56 days after dental bleaching. Ninety bovine incisors were prepared for adhesion test and adhesive remnant index (ARI) determination. The 35% hydrogen peroxide was used as a bleaching agent and the Transbond XT as a bonding agent. Statiscally significant differences were observed between all the groups (p<0.001) and were observed in the comparison of zero hour and control group (p<0.001) and in the comparison of zero hour and 24 hours (p<0.001). ARI scores (0, 1, 2 e 3) also showed statiscally differences between all the groups (p=0.011) and at the comparison of all the test groups with the control: zero hour (p=0.001), 24 hours (p=0.009), 7 days (p=0.018), 21 days (p<0.001) e 56 days (p=0.004). The shear bond strength values became significantly lower when the bracket was bonded immediately after bleaching and quickly returned to control level in 24 hours. In seven days, there was a slight increase that was not significant and recovered to normal values in the next weeks. Different patterns of fractures were observed in bleached enamel when ARI scores were analyzed. The control group showed a high frequency of 3 score and none of zero score, the opposite behavior was observed in the test groups. Copyright © 2011 Società Italiana di Ortodonzia SIDO. Published by Elsevier Srl. All rights reserved.
Vicente, Ascensión; Molina, Sara; Ortiz, Antonio J; Bravo, Luis A
2012-03-01
To evaluate the effect of food-simulating liquids on bond strengths of brackets bonded with a HEMA-free and a HEMA-containing self-etching primer. Brackets were bonded to 280 bovine incisors that were divided into two groups: (1) Adper Prompt-L-Pop (Adper PLP)/Transbond-XT and (2) Transbond Plus self-etching primer (TSEP, HEMA-free)/Transbond-XT. Each group was evaluated under different storage conditions: 24 hours in water, thermocycling (T), T/12 weeks in water, T/12 weeks in 10% ethanol, T/12 weeks in 50% ethanol, T/12 weeks in 3% acetic acid, and T/12 weeks in olive oil. Shear bond strength was measured with a universal test machine. TSEP and Adper PLP showed a significantly higher bond strength at 24 hours than at T/12 weeks in 50% ethanol (P = .000). For Adper PLP, the bond strength at 24 hours was significantly higher than T/12 weeks in water (P = .000). Significant differences were not detected between the two bonding procedures for the different storage conditions (P > .05). Owing to its hydrophilic nature, the bond strength produced by Adper PLP (a HEMA-containing self-etching primer) decreased significantly after T/12 weeks in water. Brackets bonded with both TSEP and Adper PLP showed significantly higher bond strengths at 24 hours than at T/12 weeks in 50% ethanol, probably due to the effect of ethanol at 50% on Transbond-XT.
ERIC Educational Resources Information Center
Koo, Reginald; Jones, Martin L.
2011-01-01
Quite a number of interesting problems in probability feature an event with probability equal to 1/e. This article discusses three such problems and attempts to explain why this probability occurs with such frequency.
ERIC Educational Resources Information Center
Koo, Reginald; Jones, Martin L.
2011-01-01
Quite a number of interesting problems in probability feature an event with probability equal to 1/e. This article discusses three such problems and attempts to explain why this probability occurs with such frequency.
Role of lubricants on friction between self-ligating brackets and archwires.
Leal, Renata C; Amaral, Flávia L B; França, Fabiana M G; Basting, Roberta T; Turssi, Cecilia P
2014-11-01
To evaluate the effect of different lubricants on friction between orthodontic brackets and archwires. Active (Quick, Forestadent) and passive (Damon 3MX, Ormco) self-ligating brackets underwent friction tests in the presence of mucin- and carboxymethylcellulose (CMC)-based artificial saliva, distilled water, and whole human saliva (positive control). Dry friction (no lubricant) was used as the negative control. Bracket/wire samples (0.014 × 0.025 inch, CuNiTi, SDS Ormco) underwent friction tests eight times in a universal testing machine. Two-way analysis of variance showed no significant interaction between bracket type and lubricant (P = .324). Friction force obtained with passive self-ligating brackets was lower than that for active brackets (P < .001). Friction observed in the presence of artificial saliva did not differ from that generated under lubrication with natural human saliva, as shown by Tukey test. Higher friction forces were found with the use of distilled water or when the test was performed under dry condition (ie, with no lubricant). Lubrication plays a role in friction forces between self-ligating brackets and CuNiTi wires, with mucin- and CMC-based artificial saliva providing a reliable alternative to human natural saliva.
Opening and closure forces of sliding mechanisms of different self-ligating brackets
GANDINI, Paola; ORSI, Linda; SFONDRINI, Maria Francesca; SCRIBANTE, Andrea
2013-01-01
Self-ligating brackets engage the wire by means of a slide mechanism. Forces that have to be applied to open and close the sliding mechanism of brackets are still unknown. Objective: The aim of this study was to measure and compare the opening and closure forces of different self-ligating brackets. Material and Methods: Three different stainless steel self-ligating brackets (Carriere LX, Ortho Organizers; F1000, Leone; Damon Q, Ormco) were tested. For each different bracket, 20 maxillary right central incisors and 20 mandibular right central incisors were used. Opening and closure forces were measured using an Instron Universal Testing Machine. Statistical analysis was performed and ANOVA and Tukey tests were carried out. Results: Opening forces were registered between 1.1 N and 5.6 N, whereas closure forces were recorded between 1.57 N and 4.87 N. Significant differences were detected among the different brackets and between the two prescriptions tested. Conclusion: The knowledge of different opening and closure forces of self-ligating brackets can help the orthodontist in the clinical management of these devices. PMID:23857652
Evaluation of surface roughness of the bracket slot floor--a 3D perspective study.
Agarwal, Chetankumar O; Vakil, Ketan K; Mahamuni, Avinash; Tekale, Pawankumar Dnyandeo; Gayake, Prasad V; Vakil, Jeegar K
2016-01-01
An important constituent of an orthodontic appliance is orthodontic brackets. It is either the bracket or the archwire that slides through the bracket slot, during sliding mechanics. Overcoming the friction between the two surfaces demands an important consideration in an appliance design. The present study investigated the surface roughness of four different commercially available stainless steel brackets. All tests were carried out to analyse quantitatively the morphological surface of the bracket slot floor with the help of scanning electron microscope (SEM) machine and to qualitatively analyse the average surface roughness (Sa) of the bracket slot floor with the help of a three-dimensional (3D) non-contact optical surface profilometer machine. The SEM microphotographs were evaluated with the help of visual analogue scale, the surface roughness for group A = 0-very rough surface, group C = 1--rough surface, group B = 2--smooth surface, and group D = 3-very smooth surface. Surface roughness evaluation with the 3D non-contact optical surface profilometer machine was highest for group A, followed by group C, group B and group D. Groups B and D provided smooth surface roughness; however, group D had the very smooth surface with values 0.74 and 0.75 for mesial and distal slots, respectively. Evaluation of surface roughness of the bracket slot floor with both SEM and profilometer machine led to the conclusion that the average surface roughness was highest for group A, followed by group C, group B and group D.
In vivo bracket bond strength using two adhesive systems applied under wet and dry conditions.
Ciola, Elida N; Picco, Alicia M; Sois, Ana M; Lucena, Mercedes H; Alonso, Verónica; Valvo, Maela; García, Luis; Geazzi, Ariel
2006-01-01
The purpose of this study was to investigate, in vivo, the bond strength of two adhesive materials: a moisture insensitive primer (MIP)* and a one step self etching primer (SEP)*, both used with Transbond XT* on dry and wet enamel and an adhesion time of 10-15 minutes. First or second upper and/or lower bicuspids (n = 124), to be extracted for orthodontic reasons, were used. A comparison of the materials' behavior was conducted under four different situations: 1) MIP on enamel etched and dry; 2) MIP on a surface etched and wetted with patient's saliva; 3) SEP on a dry field, 4) SEP on a saliva-wet enamel. For statistical analysis, Dunn-Sidak's multiple comparison test was applied with a probability of less than 0.05 (before correction). Stainless steel brackets with mesh-backed pads were bonded to the teeth. Bond strength was tested with modified orthodontic pliers on which a strain-gage was fixed to measure handle deformation while debonding. Moisture insensitive primer tested on wet enamel showed the highest mean bond strength outcomes (8.98 MPa) compared to one step etching primer (5.81 MPa). Statistical difference between these groups was significant (p = 0.000). Standard deviation was lower for the one-step technique, under dry and wet conditions. Since the media bond strength of SEP proved sufficient for clinical purposes and its behavior tended to be more homogeneous, this was considered the best choice.
Foliar uptake and translocation of formaldehyde with Bracket plants (Chlorophytum comosum).
Su, Yuhong; Liang, Yongchao
2015-06-30
The foliar uptake and transport of formaldehyde into Bracket plants from air via leaves and roots to external water was investigated in an air-plant-water system. The results indicated that formaldehyde could be quickly taken up by plant tissues, and that formaldehyde accumulated in leaves could be released rapidly back into air when the formaldehyde level in air was diminished. This rapid reversible translocation of formaldehyde between plant leaves and air resulted in high formaldehyde concentrations in leaf dews, depending upon exposure levels of formaldehyde in air. Meanwhile, formaldehyde could be transported from air to plant rhizosphere solution through downward transport. The concentration of formaldehyde in rhizosphere solutions increased with exposure time and the formaldehyde level in air. The efficiency of the leaf extracts to break down formaldehyde increased, probably because of an increase in oxidative potential of the leaf extracts. Taken together, the main mechanism of formaldehyde loss in air can be attributed to the accumulation by (or breakdown in) plant tissues; the removal rate of formaldehyde from air reached 135 μg h(-1) plant(-1) in the experimental condition. Copyright © 2015 Elsevier B.V. All rights reserved.
An implementation and analysis of the Abstract Syntax Notation One and the basic encoding rules
NASA Technical Reports Server (NTRS)
Harvey, James D.; Weaver, Alfred C.
1990-01-01
The details of abstract syntax notation one standard (ASN.1) and the basic encoding rules standard (BER) that collectively solve the problem of data transfer across incompatible host environments are presented, and a compiler that was built to automate their use is described. Experiences with this compiler are also discussed which provide a quantitative analysis of the performance costs associated with the application of these standards. An evaluation is offered as to how well suited ASN.1 and BER are in solving the common data representation problem.
Thomson, G.
1995-08-01
A novel ordered notation is introduced that allows description and calculation of the probability of any nuclear-pedigree configuration of disease status and marker-allele information. Algorithms are given that allow for complex models of disease predisposition, a highly polymorphic or less polymorphic marker locus, gametic disequilibrium between the marker and disease loci (marker association with disease), recombination between the marker and disease loci, and different ascertainment schemes. The theoretical foundation is presented for a series of new tests to identify modes of inheritance and genetic heterogeneity. These use marker-locus data in nuclear families from four ascertainment schemes: simplex (S), multiplex parent-child (MPC), multiplex sibs (MS),and multiplex parent-sibs (MPS). The tests are (1) extension of the antigen-genotype-frequencies-among-patients method to MPC, MS,and MPS pedigrees; (2) determination of the expected rates of transmission, or not, of marker alleles from parents to an affected child, for all pedigree types; (3) determination of expected identity by descent (IBD) values for affected sib pairs when a parent is affected (MPS pedigrees); and (4) determination of the expected marker-allele frequencies in affected-sib-pair IBD categories (MS and MPS pedigrees). A sampling strategy that includes the four pedigree types S, MPC, MS, and MPS is recommended for complex diseases once linkage and/or association of a marker with disease has been established. The full array of new and old tests that can be applied to these pedigrees provides a complementary suite of methods that can facilitate the mapping and characterization of complex human genetic traits. 50 refs., 2 figs., 2 tabs.
Analysis of Shear Bond Strength and Morphology of Er:YAG Laser-Recycled Ceramic Orthodontic Brackets
Han, Ruo-qiao; Ji, Ling-fei; Ling, Chen
2016-01-01
Objective. The aim of this study was to compare the recycling of deboned ceramic brackets via an Er:YAG laser or via the traditional chairside processing methods of flaming and sandblasting; shear bond strength and morphological changes were evaluated in recycled brackets versus new brackets. Materials and Methods. 3M Clarity Self-Ligating Ceramic Brackets with a microcrystalline base were divided into groups subjected to flaming, sandblasting, or exposure to an Er:YAG laser. New ceramic brackets served as a control group. Shear bond strengths were determined with an Electroforce test machine and tested for statistical significance through analysis of variance. Morphological examinations of the recycled ceramic bracket bases were conducted with scanning electron microscopy and confocal laser scanning microscopy. Residue on the bracket base was analyzed with Raman spectroscopy. Results. Faded, dark adhesive was left on recycled bracket bases processed via flaming. Adhesive was thoroughly removed by both sandblasting and exposure to an Er:YAG laser. Compared with new brackets, shear bond strength was lower after sandblasting (p < 0.05), but not after exposure to an Er:YAG laser. The Er:YAG laser caused no damage to the bracket. Conclusion. Er:YAG lasers effectively remove adhesive from the bases of ceramic brackets without damaging them; thus, this method may be preferred over other recycling methods. PMID:27047964
Poisson brackets of mappings obtained as ( q,- p) reductions of lattice equations
NASA Astrophysics Data System (ADS)
Tran, Dinh T.; van der Kamp, Peter H.; Quispel, G. R. W.
2016-11-01
In this paper, we present Poisson brackets of certain classes of mappings obtained as general periodic reductions of integrable lattice equations. The Poisson brackets are derived from a Lagrangian, using the so-called Ostrogradsky transformation. The ( q,- p) reductions are ( p + q)-dimensional maps and explicit Poisson brackets for such reductions of the discrete KdV equation, the discrete Lotka-Volterra equation, and the discrete Liouville equation are included. Lax representations of these equations can be used to construct sufficiently many integrals for the reductions. As examples we show that the (3,-2) reductions of the integrable partial difference equations are Liouville integrable in their own right.
Torque expression of 0.018 and 0.022 inch conventional brackets.
Sifakakis, Iosif; Pandis, Nikolaos; Makou, Margarita; Eliades, Theodore; Katsaros, Christos; Bourauel, Christoph
2013-10-01
The aim of this study was to assess the effect of the moments generated with low- and high-torque brackets. Four different bracket prescription-slot combinations of the same bracket type (Mini Diamond® Twin) were evaluated: high-torque 0.018 and 0.022 inch and low-torque 0.018 and 0.022 inch. These brackets were bonded on identical maxillary acrylic resin models with levelled and aligned teeth and each model was mounted on the orthodontic measurement and simulation system (OMSS). Ten specimens of 0.017 × 0.025 inch and ten 0.019 × 0.025 inch stainless steel archwires (ORMCO) were evaluated in the low- and high-torque 0.018 inch and 0.022 inch brackets, respectively. The wires were ligated with elastomerics into the brackets and each measurement was repeated once after religation. Two-way analysis of variance and t-test were conducted to compare the generated moments between wires at low- and high-torque brackets separately. The maximum moment generated by the 0.017 × 0.025 inch stainless steel archwire in the 0.018 inch brackets at +15 degrees ranged from 14.33 and 12.95 Nmm for the high- and low-torque brackets, respectively. The measured torque in the 0.022 inch brackets with the 0.019 × 0.025 inch stainless steel archwire was 9.32 and 6.48 Nmm, respectively. The recorded differences of maximum moments between the high- and low-torque series were statistically significant. High-torque brackets produced higher moments compared with low-torque brackets. Additionally, in both high- and low-torque configurations, the thicker 0.019 × 0.025 inch steel archwire in the 0.022 inch slot system generated lower moments in comparison with the 0.017 × 0.025 inch steel archwire in the 0.018 inch slot system.
NASA Astrophysics Data System (ADS)
Fedulov, Boris N.; Safonov, Alexander A.; Sergeichev, Ivan V.; Ushakov, Andrey E.; Klenin, Yuri G.; Makarenko, Irina V.
2016-10-01
An application of composites for construction of subway brackets is a very effective approach to extend their lifetime. However, this approach involves the necessity to prevent process-induced distortions of the bracket due to thermal deformation and chemical shrinkage. At present study, a process simulation has been carried out to support the design of the production tooling. The simulation was based on the application of viscoelastic model for the resin. Simulation results were verified by comparison with results of manufacturing experiments. To optimize the bracket structure the strength analysis was carried out as well.
2014-01-01
Background Ambiscript is a graphically-designed nucleic acid notation that uses symbol symmetries to support sequence complementation, highlight biologically-relevant palindromes, and facilitate the analysis of consensus sequences. Although the original Ambiscript notation was designed to easily represent consensus sequences for multiple sequence alignments, the notation’s black-on-white ambiguity characters are unable to reflect the statistical distribution of nucleotides found at each position. We now propose a color-augmented ambigraphic notation to encode the frequency of positional polymorphisms in these consensus sequences. Results We have implemented this color-coding approach by creating an Adobe Flash® application ( http://www.ambiscript.org) that shades and colors modified Ambiscript characters according to the prevalence of the encoded nucleotide at each position in the alignment. The resulting graphic helps viewers perceive biologically-relevant patterns in multiple sequence alignments by uniquely combining color, shading, and character symmetries to highlight palindromes and inverted repeats in conserved DNA motifs. Conclusion Juxtaposing an intuitive color scheme over the deliberate character symmetries of an ambigraphic nucleic acid notation yields a highly-functional nucleic acid notation that maximizes information content and successfully embodies key principles of graphic excellence put forth by the statistician and graphic design theorist, Edward Tufte. PMID:24447494
Doğramac, Sera N; Watsford, Mark L; Murphy, Aron J
2011-03-01
Subjective notational analysis can be used to track players and analyse movement patterns during match-play of team sports such as futsal. The purpose of this study was to establish the validity and reliability of the Event Recorder for subjective notational analysis. A course was designed, replicating ten minutes of futsal match-play movement patterns, where ten participants undertook the course. The course allowed a comparison of data derived from subjective notational analysis, to the known distances of the course, and to GPS data. The study analysed six locomotor activity categories, focusing on total distance covered, total duration of activities and total frequency of activities. The values between the known measurements and the Event Recorder were similar, whereas the majority of significant differences were found between the Event Recorder and GPS values. The reliability of subjective notational analysis was established with all ten participants being analysed on two occasions, as well as analysing five random futsal players twice during match-play. Subjective notational analysis is a valid and reliable method of tracking player movements, and may be a preferred and more effective method than GPS, particularly for indoor sports such as futsal, and field sports where short distances and changes in direction are observed.
Wendl, B; Muchitsch, P; Pichelmayer, M; Droschl, H; Kern, W
2011-06-01
An average rate of bracket loss of between 4.7 and 6 per cent is to be expected in daily clinical orthodontic practice during a typical 2 year treatment period. For reasons of economy, detached brackets are commonly reattached after sandblasting to remove adhesive, or replaced with used brackets reconditioned by specialist companies. In the present study, sandblasting and specialist bracket-reconditioning procedures were systematically compared by comparative shear testing of rebonded, reconditioned, and new brackets (n = 160) using light- and chemically cured adhesives. Statistical analysis was carried out with Kruskal-Wallis and Mann-Whitney tests. The mean bond strength of reconditioned brackets was, in each case, lower than that of new brackets, with the lowest value obtained with sandblasted brackets. This nevertheless exceeded the minimum recommended value of 5-8 MPa. Bond strength was generally higher with chemically than with light-curing adhesive; the chemically curing adhesive provided bond strength on previously bonded enamel higher than the light-curing adhesive on intact teeth. Consistent with this, the results of the adhesive remnant index (ARI) demonstrated improved bonding with the chemically curing than the light-curing adhesive to the bracket base. Despite resulting in a weaker bond strength compared with new brackets, sandblasting brackets accidentally detached during orthodontic treatment will generally allow effective reattachment to be achieved. Bond strength can be improved with the use of a chemically cured adhesive. Used brackets reconditioned by specialist companies provide a second alternative to new brackets and higher bond strengths than sandblasted brackets.
Sampling probability distributions of lesions in mammograms
NASA Astrophysics Data System (ADS)
Looney, P.; Warren, L. M.; Dance, D. R.; Young, K. C.
2015-03-01
One approach to image perception studies in mammography using virtual clinical trials involves the insertion of simulated lesions into normal mammograms. To facilitate this, a method has been developed that allows for sampling of lesion positions across the cranio-caudal and medio-lateral radiographic projections in accordance with measured distributions of real lesion locations. 6825 mammograms from our mammography image database were segmented to find the breast outline. The outlines were averaged and smoothed to produce an average outline for each laterality and radiographic projection. Lesions in 3304 mammograms with malignant findings were mapped on to a standardised breast image corresponding to the average breast outline using piecewise affine transforms. A four dimensional probability distribution function was found from the lesion locations in the cranio-caudal and medio-lateral radiographic projections for calcification and noncalcification lesions. Lesion locations sampled from this probability distribution function were mapped on to individual mammograms using a piecewise affine transform which transforms the average outline to the outline of the breast in the mammogram. The four dimensional probability distribution function was validated by comparing it to the two dimensional distributions found by considering each radiographic projection and laterality independently. The correlation of the location of the lesions sampled from the four dimensional probability distribution function across radiographic projections was shown to match the correlation of the locations of the original mapped lesion locations. The current system has been implemented as a web-service on a server using the Python Django framework. The server performs the sampling, performs the mapping and returns the results in a javascript object notation format.
The Astronomy Workshop: Enhanced Tools "scientific Notation" And "solar System Visualizer"
NASA Astrophysics Data System (ADS)
Hayes-Gehrke, Melissa N.; Hamilton, D.; Deming, G.
2007-12-01
The Astronomy Workshop (http://janus.astro.umd.edu) is a collection of interactive World Wide Web tools that were developed under the direction of Doug Hamilton for use in undergraduate classes and by the general public. The philosophy of the site is to foster student interest in astronomy by using their fascination with computers and the internet. We are upgrading the "Scientific Notation" tool; its initial function was to enable the practice of changing decimal numbers into scientific notation numbers. This tool is very popular, with 10,000 hits per day typically. The upgrades include multiplication and division and the implementation of automatically-graded quizzes. We have also added a new tool, the "Solar System Visualizer", which animates orbits of the solar system's planets, moons, and rings to the correct scale (including retrograde motions), as well as displaying the orbits of a number of extrasolar systems to scale. We are gradually adding instructor materials and student activities to enhance the instructional use of the web tools.
García-Orza, Javier; Perea, Manuel; Abu Mallouh, Reem; Carreiras, Manuel
2012-04-01
Numerical quantity seems to affect the response in any task that involves numbers, even in tasks that do not demand access to quantity (e.g., perceptual tasks). That is, readers seem to activate quantity representations upon the mere presentation of integers. One important piece of evidence in favor of this view comes from the finding of a distance effect in perceptual tasks: When one compares two numbers, response times (RTs) are a function of the numerical distance between them. However, recent studies have suggested that the physical similarity between Arabic numbers is strongly correlated with their numerical distance, and that the former could be a better predictor of RT data in perceptual tasks in which magnitude processing is not required (Cohen, 2009a). The present study explored the Persian and Arabic versions of Indian numbers (Exps. 1 and 2, respectively). Naïve participants (speakers of Spanish) and users of these notations (Pakistanis and Jordanians) participated in a physical same-different matching task. The RTs of users of the Indian notations were regressed on perceptual similarity (estimated from the Spanish participants' RTs) and numerical distance. The results showed that, regardless of the degree of correlation between the perceptual similarity function and the numerical distance function, the critical predictor for RTs was perceptual similarity. Thus, participants do not automatically activate Indian integers' quantity representations, at least not when these numbers are presented in simple perceptual tasks.
Yadav, Sarjeev Singh; Sonkurla, Sapna
2013-01-01
To give notation for quadrants, tooth position, and the type of supernumerary teeth for both permanent and deciduous dentition. Tooth numbering provides dentists with an essential shortcut in clinical record keeping. Three systems are favored worldwide: the Zsigmondy/Palmer system, the Universal system, and the Federation Dentaire Internationale (FDI) Two-Digit system. Histories of all tooth-numbering methods were traced and the strengths and deficiencies of each system were reviewed. The FDI Two-Digit system is widely used throughout the world, except USA, and is the only method that makes the visual sense, cognitive sense, and computer sense. On review it was noticed that all tooth notation systems in vogue have a drawback as they do not provide any information or notations for supernumerary teeth such as paramolar, distomolar, mesiodens, and fused teeth.
Lifting of the Vlasov-Maxwell bracket by Lie-transform method
NASA Astrophysics Data System (ADS)
Brizard, A. J.; Morrison, P. J.; Burby, J. W.; de Guillebon, L.; Vittot, M.
2016-12-01
The Vlasov-Maxwell equations possess a Hamiltonian structure expressed in terms of a Hamiltonian functional and a functional bracket. In the present paper, the transformation (`lift') of the Vlasov-Maxwell bracket induced by the dynamical reduction of single-particle dynamics is investigated when the reduction is carried out by Lie-transform perturbation methods. The ultimate goal of this work is to provide an explicit pathway to the Hamiltonian formulations for the guiding-centre and gyrokinetic Vlasov-Maxwell equations, which have found important applications in our understanding of turbulent magnetized plasmas. Here, it is shown that the general form of the reduced Vlasov-Maxwell equations possesses a Hamiltonian structure defined in terms of a reduced Hamiltonian functional and a reduced bracket that automatically satisfies the standard bracket properties.
Laser brackets debonding: Tm:YAP and ClarityTM SL self-ligating appliance system
NASA Astrophysics Data System (ADS)
Dostálová, Tatjana; Jelínková, Helena; Šulc, Jan; Koranda, Petr; Němec, Michal; Jelínek, Michal; Fibrich, Martin; Michalik, Pavel; Miyagi, Mitsunobu
2010-02-01
The study demonstrates the possibility of using Tm:YAP laser radiation for the removing ceramic brackets. The amount of enamel loss and residual resin on teeth has been evaluated. A diode-pumped Tm:YAP microchip laser generating at wavelength 1.9 μm was used for the debonding process. The transmission and absorption measurement of the basic elements - bracket, adhesive resin, and enamel was analyzed to explain the source of the heat and bracket debonding. Quantitative measurements are made for visualizing enamel surface before and after a self-ligating bonding technique. Temperature rise observation during the debonding procedure - from 0.5 to 2 W power - has improved the accuracy of assessment. The results were evaluated by CCD camera and scanning electron microscope. From the measurements it is possible to conclude that continuously running small diode pumped Tm:YAP microchip laser having output power 1W can remove the ceramic bracket without enamel iatrogenic damage.
Laser brackets debonding: Tm:YAP, Nd:YAG, and GaAs diode lasers evaluation
NASA Astrophysics Data System (ADS)
Dostálová, Tat'jana; Jelínková, Helena; Šulc, Jan; Koranda, Petr; Němec, Michal; Ivanov, Ilja; Miyagi, Mitsunobu; Iwai, Katsumasa
2009-02-01
The study demonstrates the possibility of using laser radiation for the ceramic bracket removing. Three laser radiations were examined for this effect and the removing possibility and velocity together with enamel and root damage were investigated. A diode pumped Tm:YAP microchip laser generating a wavelength 1.9 μm, diode pumped Nd:YAG laser with 1.44 μm wavelength, GaAs diode with 0.808 μm were used for the debonding purpose. The measurement of transmission and absorption of the basic element - bracket, adhesive resin, and enamel was also made with the goal to explain the source of the heat and bracket debonding. The explanation of the debonding effect is also presented. From the results it is possible to conclude that continuously running diode pumped microchip Tm:YAP laser having output power 1W can be a good candidate for ceramic bracket debonding procedure.
King, L; Smith, R T; Wendt, S L; Behrents, R G
1987-04-01
A method of curing light-cured composite resins by transillumination to cement acid-etched fixed partial dentures was adapted to bond solid mesh-backed lingual orthodontic brackets. Results of this investigation showed that the bond strengths of the orthodontic brackets bonded with light-cured composite resins were significantly less (P less than 0.05) than the bond strengths of the orthodontic brackets cemented with traditional adhesives and orthodontic composite resins. Notwithstanding, the bond strengths achieved with the transilluminated light-cured composite resins should be adequate to withstand the forces of mastication and orthodontic movements. There was no correlation of bond strengths of the brackets cemented with the transilluminated light-cured composite resins when compared to the faciolingual widths of the teeth.
The rationale, evolution and clinical application of the self-ligating bracket.
Damon, D H
1998-08-01
There is ample evidence in the literature that conventional orthodontic mechanics while intended to move teeth efficiently rarely achieve atraumatic remodeling of periodontal tissues. The vascular supply is often interrupted, which in turn affects the oxidative metabolism. Moreover, teeth splinted in groups do not appear to move as efficiently as single teeth. The novel bracket design and treatment regimen described in this report allow teeth to move individually, yet stay within a group. The self-ligating bracket design allows for rapid leveling because teeth drift along the path of least resistance with little or no friction between the bracket and slot of the wire. The hinge mechanism eliminates much of the friction created by the conventional wire or latex ties used to secure the archwire in the bracket slot. Thus, sliding mechanics is achieved in the true sense of the word. This system is capable of increasing the appointment intervals, and possibly reducing the overall treatment time.
Comparison of bond strength between simple foil mesh and laser-structured base retention brackets.
Sorel, Olivier; El Alam, Rafeh; Chagneau, Francis; Cathelineau, Guy
2002-09-01
The aims of the current study were to evaluate the bond strength of a new metallic orthodontic bracket with a laser structured base (Discovery, Dentaurum, Ispringen, Germany), and its effects on the site of bond failure and on the behavior of the enamel after debonding. One hundred and twenty recently extracted human premolars were bonded with 1 of 2 types of mechanical interlock base metal brackets: a standard system with a simple foil mesh pad (Minitrim, Dentaurum) and the Discovery bracket. A resin-based, chemically activated bonding system, No-mix (Dentaurum), was used as the adhesive system in this trial. The teeth were immersed in normal saline solution at 37 degrees C for 7 days before debonding and were randomly assigned to different subgroups. A testing machine was used to evaluate tensile and fatigue bond strengths for both brackets. After debonding, the amount of residual adhesive on the bracket and enamel detachment were assessed according to the adhesive remnant index (ARI) and the enamel detachment index (EDI) with a scanning electron microscope and an energy dispersive X-ray spectrometer. The scores obtained from the ARI and the EDI showed that the laser structured base brackets had a significantly higher bond strength (mean +/- SD: 17.1 +/- 0.7 MPa) that was 2 times higher than that observed with the simple foil mesh brackets (mean +/- SD: 8.7 +/- 1.4 MPa) (P <.001). Bond failure with the laser structured base was at the enamel-adhesive interface with an ARI score of 3 in 80% of the teeth, and bond failure with the simple foil mesh base was at the bracket-adhesive interface with an ARI score of 0 in 75% of the teeth. A small area, with less than 10% of the enamel damaged (1 on the EDI) and 1.5 microm in thickness, was observed for both brackets. The laser structured base bracket's bond strength was double that of the simple foil mesh bracket but was equally safe and did not induce significant enamel detachment.
IMPROVEMENTS TO POLAR CAMPS - JAMESWAY CEILING HANGER BRACKET AND CURTAIN RODS.
New ceiling hanger brackets and curtain rods were developed to increase the speed of installation of curtain partitions in Jamesways and to provide a...represents a saving of $152 in outfitting a 12-bedroom Jamesway quarters. It is planned to use the ceiling hanger brackets and curtain rods to outfit a...64-foot Jamesway as a 12-man quarters for in-service test at McMurdo, Antarctica, during Deep Freeze 67. (Author)
Shahabi, M; Jahanbin, A; Esmaily, H; Sharifi, H; Salari, S
2011-01-01
Resistance to corrosion is an advantageous property of orthodontic brackets; however, due to low levels of pH found in the mouth of a patient, localized corrosion may occur This can affect tooth movement by increasing friction between the arch wire and bracket slot and initiate enamel discoloration. Additionally, corrosion causes the release of elements that may lead to cytotoxic and biological side effects. The aim of this study was to compare the amount of corrosion caused by lemon juice, vinegar and Coca-Cola on orthodontic brackets in vitro and then to recommend the most suitable diet during orthodontic treatment. Sixty orthodontic brackets in three groups of twenty were immersed in a test solution (Fusamaya-Meyer artificial saliva plus lemon juice, vinegar or Coca-Cola) at a temperature of 37 degrees C +/- 1. Moreover, a negative control consisting of twenty brackets were put in pure artificial saliva. After 6 weeks the amount of corrosion was determined by measuring delta W of mean weights of brackets and the results were analyzed by general linear models (repeated measurement). Significant differences were seen during different weeks of the study (P < 0.001) and different solutions (P < 0.001). This study showed the amount of corrosion in orthodontic brackets was the most for cola followed by vinegar and then lemon juice. In addition, mean differences for cola versus lemon juice was -0.010 (sig. <0.001), vinegar versus lemon juice was -0.006 (sig. = 0.001) and cola versus vinegar was -0.004 (sig. = 0.013). Acidic effervescent soft drinks such as cola have to be eliminated or minimized in the nutritional diet of orthodontic patients because of their harmful effects on their brackets.
Santin, Gabriela Cristina; Palma-Dibb, Regina Guenka; Romano, Fábio Lourenço; de Oliveira, Harley Francisco; Nelson Filho, Paulo; de Queiroz, Alexandra Mussolino
2015-08-01
The increasing success rates for cancer patients treated with radiotherapy and the frequent occurrence of tooth loss during treatment have led to an increased demand for orthodontic treatment after radiotherapy. The aim of this study was to evaluate tooth enamel of irradiated teeth after the bonding and debonding of metal and ceramic brackets. Ten permanent molars were cut into enamel fragments measuring 1 mm(2) and divided into an irradiated group (total dose of 60 Gy) and a nonirradiated group. The fragments were subjected to microshear testing to evaluate whether radiotherapy altered the strength of the enamel. Furthermore, 90 prepared premolars were divided into 6 groups and subgroups (n = 15): group 1, nonirradiated and nonaged; group 2, nonirradiated and aged (thermal cycled); group 3, irradiated and aged; each group was divided into 2 subgroups: metallic and ceramic brackets. After thermal cycling and radiotherapy, the brackets were bonded onto the specimens with Transbond XT (3M Unitek, Monrovia, Calif). After 24 hours, the specimens were subjected to the shear tests. Images of the enamel surfaces were classified using the adhesive remnant index. The composite resin-enamel interface was also evaluated. Enamel fragments subjected to radiation had lower strength than did the nonirradiated samples (P <0.05). The groups and subgroups submitted to radiation and bonded ceramic brackets had the lowest strength values. Groups 1 and 2 with metallic brackets had less adhesive on the surface, whereas groups 1 and 2 with ceramic brackets and group 3 with both metallic and ceramic brackets had more adhesive on the surfaces. On the images of the composite resin-enamel interface, resin tags were more extensive on irradiated tooth enamel. Radiation decreased tooth enamel strength, and the specimens treated with radiotherapy had higher frequencies of adhesive failure between the bracket and the composite resin as well as more extensive tags. Copyright © 2015 American
Shear bond strength of orthodontic brackets cemented with a zinc oxide-polyvinyl cement.
Martin, S; Garcia-Godoy, F
1994-12-01
The purpose of this study was to compare the shear bond strengths and enamel surface structure after debonding a conventional metal bracket and a polycrystalline ceramic bracket bonded with a bipolar zinc oxide-polyvinyl cement (F-21) or a light-cured resin cement (Transbond). Forty extracted human premolars were used. The buccal enamel surfaces were used, and the teeth randomly divided into four groups of 10 teeth each: group 1: conventional metal bracket (Unitek) bonded with Transbond; group 2: metal bracket bonded with F-21; group 3: ceramic bracket (Transcend 2000) bonded with Transbond; and group 4: ceramic bracket bonded with F-21. The brackets were bonded to the etched enamel surfaces according to manufacturer's instructions. All specimens were stored in distilled water for 24 hours and then thermocycled for 300 cycles between 5 degrees C and 55 degrees C. The specimens were mounted in dental stone and placed in the Instron at a crosshead speed of 0.5 mm/min with a knife-edged blade. Immediately after debonding, the enamel surface and bracket-enamel interface were evaluated visually and with a stereomicroscope. Representative samples were then examined with the scanning electron microscope. The analysis of variance and Student-Newman-Keuls tests were performed. The results in megapascals were Group 1: 19,6 (+/- 9,6); group 2: 14,3 (+/- 4,6); group 3: 28,8 (+/- 12,6); and group 4: 18,5 (+/- 7,5). Group 3 was statistically significantly different (P < 0.008) from all other groups. Groups 1, 2, and 4 were not significantly different.(ABSTRACT TRUNCATED AT 250 WORDS)
Bakhtinov, A. P. Vodopyanov, V. N.; Netyaga, V. V.; Kudrynskyi, Z. R.; Lytvyn, O. S.
2012-03-15
Features of the formation of Au/Ni/ Left-Pointing-Angle-Bracket C Right-Pointing-Angle-Bracket /n-Ga{sub 2}O{sub 3} hybrid nanostructures on a Van der Waals surface (0001) of 'layered semiconductor-ferroelectric' composite nanostructures (p-GaSe Left-Pointing-Angle-Bracket KNO{sub 3} Right-Pointing-Angle-Bracket ) are studied using atomic-force microscopy. The room-temperature current-voltage characteristics and the dependence of the impedance spectrum of hybrid structures on a bias voltage are studied. The current-voltage characteristic includes a resonance peak and a portion with negative differential resistance. The current attains a maximum at a certain bias voltage, when electric polarization switching in nanoscale three-dimensional inclusions in the layered GaSe matrix occurs. In the high-frequency region (f > 10{sup 6} Hz), inductive-type impedance (a large negative capacitance of structures, {approx}10{sup 6} F/mm{sup 2}) is detected. This effect is due to spinpolarized electron transport in a series of interconnected semiconductor composite nanostructures with multiple p-GaSe Left-Pointing-Angle-Bracket KNO{sub 3} Right-Pointing-Angle-Bracket quantum wells and a forward-biased 'ferromagnetic metal-semiconductor' polarizer (Au/Ni/ Left-Pointing-Angle-Bracket C Right-Pointing-Angle-Bracket /n{sup +}-Ga{sub 2}O{sub 3}/n-Ga{sub 2}O{sub 3}). A shift of the maximum (current hysteresis) is detected in the current-voltage characteristics for various directions of the variations in bias voltage.
Shear bond strength of a new polycarbonate bracket--an in vitro study with 14 adhesives.
Akin-Nergiz, N; Nergiz, I; Behlfelt, K; Platzer, U
1996-06-01
Shear bond strength and failure location were used to evaluate the effectiveness of plastic bracket primers for bonding diacrylate adhesives on a new fibre-reinforced polycarbonate bracket. Maxillary incisor polycarbonate and mesh-based brackets as control were bonded to human incisors with 14 different adhesives (four filled diacrylate two-paste, six diacrylate one-step and four power-liquid acrylic adhesives), and after thermo-cycling for 2000 cycles between 5 degrees and 55 degrees C, tested in shear. A non-parametric test (Mann-Whitney U test) was used to compare the shear bond strength of the polycarbonate brackets with the mesh based brackets and a One-way test (according to Scheffe) to compare the shear bond strength of different adhesives. The following conclusions can be made: 1. Seven of the 14 adhesives used in this study with both types of brackets demonstrated adequate shear bond strength values for the clinical application. The exceptions were: Achieve Mix, No-Mix:30 Silkon, Lee Insta-Bond, Ortho-Loc and Bond-Eze, all with too low a shear bond strength for one or both types of brackets, and finally Quasar, which used with the plastic brackets sometimes caused enamel fractures, due to high bond strength. 2. The adhesives with their own plastic primer demonstrated higher blood strength values than those without plastic primer, and two-paste adhesives used with plastic primer displayed a higher bond strength than the other adhesives. 3. Generally, the shear bond strength values of the one-step adhesives were lower compared with the two-paste adhesives. 4. The liquid-powder adhesives demonstrated very different values for bond strength.
Six-month bracket failure rate evaluation of a self-etching primer.
Elekdag-Turk, Selma; Isci, Devrim; Turk, Tamer; Cakmak, Fethiye
2008-04-01
The aim of this study was to compare the clinical performance of a self-etching primer (SEP) with a conventional two-step etch and primer [conventional method (CM)]. The chair time required for bonding was also evaluated. Thirty-seven patients (14 males and 23 females) with a mean age of 16 years 5 months were included in the study. Six hundred and seventy-two brackets were bonded by one operator using a split-mouth design, with either SEP (Transbond Plus) or CM (Transbond XT). Bracket failure rates were estimated with respect to bonding procedure, dental arch, type of tooth (incisor, canine, and premolar), and gender. The results were evaluated using the chi-square test. The survival rate of the brackets was estimated with Kaplan-Meier analysis. Bracket survival distributions with respect to bonding procedure, dental arch, type of tooth, and patient gender were compared with a log-rank test. Bond failure interface was determined with the adhesive remnant index (ARI). The failure rates were 0.6 per cent for both bonding procedures. The failure and survival rates did not show significant differences between the bonding procedures, upper and lower dental arches, or gender. However, premolar brackets displayed a higher bond failure rate and a lower survival rate than incisor and canine brackets (P < 0.05). The mean bracket bonding time per tooth with SEP was significantly shorter than with CM (P < 0.001). No significant difference was observed for the ARI scores (P > 0.05). The results of this in vivo, randomized, cross-mouth clinical trial demonstrated a high survival rate with Transbond Plus. This finding indicates that SEP can be effectively used for bonding of orthodontic brackets.
Probability and Relative Frequency
NASA Astrophysics Data System (ADS)
Drieschner, Michael
2016-01-01
The concept of probability seems to have been inexplicable since its invention in the seventeenth century. In its use in science, probability is closely related with relative frequency. So the task seems to be interpreting that relation. In this paper, we start with predicted relative frequency and show that its structure is the same as that of probability. I propose to call that the `prediction interpretation' of probability. The consequences of that definition are discussed. The "ladder"-structure of the probability calculus is analyzed. The expectation of the relative frequency is shown to be equal to the predicted relative frequency. Probability is shown to be the most general empirically testable prediction.
Measurements of the torque moment in various archwire-bracket-ligation combinations.
Hirai, Miyuki; Nakajima, Akira; Kawai, Nobuhiko; Tanaka, Eiji; Igarashi, Yu; Sakaguchi, Masahito; Sameshima, Glenn T; Shimizu, Noriyoshi
2012-06-01
The torque moment generated by third-order bends is important for tooth movement. The purpose of this study was to measure the torque moment that can be delivered by various archwire and bracket combinations at the targeted tooth. Stainless steel (SS) upper brackets with 0.018 and 0.022 inch slots, two sizes of nickel-titanium (Ni-Ti) alloy wires, and three sizes of SS wires for each bracket were used. The wire was ligated with elastics or wire. The torque moment delivered by the various archwire-bracket-ligation combinations was measured using a torque gauge. Statistical analysis was undertaken using analysis of variance (multiple comparison tests and post hoc using Tukey's honestly significant difference test. The torque moment increased as the degree of torque and wire size increased. There was no significant difference in torque moment between the SS and Ni-Ti wires at lower or higher than 40 degrees torque. The torque moment with wire ligation was significantly larger than that with elastic ligation with 0.016 × 0.022 and 0.017 × 0.025 inch Ni-Ti wires in the 0.018 inch slot brackets and the 0.017 × 0.025 and 0.019 × 0.025 inch SS and Ni-Ti wires in the 0.022 inch slot brackets. However, there was no significant difference in torque moment between either ligation method when using the full slot size wires.
Atash, Ramin; Fneiche, Ali; Cetik, Sibel; Bahrami, Babak; Balon-Perin, Alain; Orellana, Maria; Glineur, Régine
2017-01-01
Adhesives systems have a drawback when utilized for bonding orthodontic brackets: they shrink during photopolymerization creating microleakage. The aim of this study was to assess the stability of different orthodontic adhesives around brackets and enamel. Sixty noncarious mandibular premolars extracted for orthodontic reasons were randomly divided into six groups of adhesives used for bonding brackets to dental enamel: NeoBond(®) Light Cure Adhesive Kit, Transbond™ Plus Self-Etching, Victory V-Slot APC PLUS(®) + Transbond™ MIP, Rely-A-Bond(®) Kit, Light Cure Orthodontic Adhesive Kit (OptiBond(®)), and Transbond™ MIP. Following bonding, all teeth underwent 2500 cycles of thermal cycling in baths ranging from 5°C to 55°C before being immersed in 2% methylene blue for 24 h. All samples were examined under a binocular microscope to assess the degree of microleakage at the "bracket-adhesive" and "adhesive-enamel" interfaces in the gingival and occlusal regions of the bracket. A significant difference was found at the "occlusal bracket-adhesive" interface. The highest microleakage values were found in the occlusal region, although no significant. Microleakage was observed in all groups. Group 2 had the highest microleakage values whereas Group 6 had the lowest values.
Montero, Manuela M Haro; Vicente, Ascensión; Alfonso-Hernández, Noelia; Jiménez-López, Manuel; Bravo-González, Luis-Alberto
2015-05-01
To evaluate in vitro the shear bond strength of brackets recycled by sandblasting with aluminum oxide particles of different sizes or reconditioned industrially after successive rebonding. Eighty brackets were bonded and debonded sequentially three times. After the first debonding, brackets were divided into four groups: (group 1) sandblasting with aluminum oxide particles of 25 μ, (group 2) 50 μ, and (group 3) 110 μ, and (group 4) industrial recycling. Bond strength and adhesive material remaining on debonded bracket bases were evaluated for each successive debond. No significant differences were detected between the four groups following the first recycle (P > .05). After the second recycle, bond strength was significantly greater for the industrially recycled group than the other groups (P < .016). When shear bond strength was compared within each recycling method, the bond strength of sandblasted brackets decreased with the increase of particle size and with each recycle; for the industrially recycled group, no significant differences were detected between the three sequences (P > .016). In the evaluation of bond material remnant, the industrially recycled group left significantly less bond material after successive recycling than the other groups did (P < .016). Within each recycling method, the adhesive remnant decreased significantly after successive debond (P < .016). Industrial recycling obtained better results than sandblasting after three successive debondings. The brackets' shear bond strength decreased as the size of the aluminum oxide particle used for sandblasting increased and as recycling was repeated.
Comparison of Shear Bond Strength of RMGI and Composite Resin for Orthodontic Bracket Bonding
Yassaei, Soghra; Davari, Abdolrahim; Goldani Moghadam, Mahjobeh; Kamaei, Ahmad
2014-01-01
Objective: The aim of this study was to compare the shear bond strength (SBS) of resin modified glass ionomer (RMGI) and composite resin for bonding metal and ceramic brackets. Materials and Methods: Eighty-eight human premolars extracted for orthodontic purposes were divided into 4 groups (n=22). In groups 1 and 2, 22 metal and ceramic brackets were bonded using composite resin (Transbond XT), respectively. Twenty-two metal and ceramic brackets in groups 3 and 4, respectively were bonded using RMGI (Fuji Ortho LC, Japan). After photo polymerization, the teeth were stored in water and thermocycled (500 cycles between 5° and 55°). The SBS value of each sample was determined using a Universal Testing Machine. The amount of residual adhesive remaining on each tooth was evaluated under a stereomicroscope. Statistical analyses were done using two-way ANOVA. Results: RMGI bonded brackets had significantly lower SBS value compared to composite resin bonded groups. No statistically significant difference was observed between metal and ceramic brackets bonded with either the RMGI or composite resin. The comparison of the adhesive remnant index (ARI) scores between the groups indicated that the bracket failure mode was significantly different among groups (P<0.001) with more adhesive remaining on the teeth bonded with composite resin. Conclusion: RMGIs have significantly lower SBS compared to composite resin for orthodontic bonding purposes; however the provided SBS is still within the clinically acceptable range. PMID:25628663
Effect of pumice prophylaxis on the bond strength of orthodontic brackets.
Lindauer, S J; Browning, H; Shroff, B; Marshall, F; Anderson, R H; Moon, P C
1997-06-01
Pumice prophylaxis has long been accepted as a prerequisite for achieving adequate enamel etching during orthodontic bonding procedures. Three methods were used in this study to examine the effects of pumice prophylaxis on the bond strength of orthodontic brackets: (1) shear bond strength of brackets that were bonded to extracted premolars after surface preparation procedures, which either included or did not include prior pumice prophylaxis, was evaluated; (2) scanning electron microscopy (SEM) was used to examine the surface characteristics of teeth that had been etched with and without prior pumice prophylaxis; and (3) rate of bracket failure in patients who had had brackets bonded with and without prior pumice prophylaxis was recorded during an average treatment time of 18 months. No significant differences were noted in bond strength, general etched enamel surface characteristics, or bracket retention rates. Some specific differences, however, were noted on SEM in localized areas of the etched enamel surfaces, although these did not appear to affect the bond strength or bracket retention rates ultimately attained.
Higa, Rodrigo Hitoshi; Semenara, Nayara Thiago; Henriques, José Fernando Castanha; Janson, Guilherme; Sathler, Renata; Fernandes, Thais Maria Freire
2016-01-01
ABSTRACT Introduction: The aim of the study was to evaluate deflection forces of rectangular orthodontic wires in conventional (MorelliTM), active (In-Ovation RTM) and passive (Damon 3MXTM) self-ligating brackets. Material and Methods: Two brands of stainless steel and nickel-titanium (NiTi) wires (MorelliTM and GACTM), in addition to OrmcoTM copper-nickel-titanium wires were used. Specimens were assembled in a clinical simulation device especially designed for this study and tested in an Instron universal testing machine. For the testing procedures, an acrylic structure representative of the maxillary right central incisor was lingually moved in activations of 0 to 1 mm, with readings of the force released by deflection in unloading of 0.5, 0.8 and 1 mm at a constant speed of 2 mm/min. Inter-bracket forces with stainless steel, NiTi and CuNiTi were individually compared by two-way ANOVA, followed by Tukey’s tests. Results: Results showed that there were lower forces in conventional brackets, followed by active and passive self-ligating brackets. Within the brands, only for NiTi wires, the MorelliTM brand presented higher forces than GACTM wires. Conclusions: Bracket systems provide different degrees of deflection force, with self-ligating brackets showing the highest forces. PMID:28125144
Hersche, Sepp; Sifakakis, Iosif; Zinelis, Spiros; Eliades, Theodore
2017-02-01
The purpose of the present study was to investigate the elemental composition, the microstructure, and the selected mechanical properties of high gold orthodontic brackets after intraoral aging. Thirty Incognito™ (3M Unitek, Bad Essen, Germany) lingual brackets were studied, 15 brackets as received (control group) and 15 brackets retrieved from different patients after orthodontic treatment. The surface of the wing area was examined by scanning electron microscopy (SEM). Backscattered electron imaging (BEI) was performed, and the elemental composition was determined by X-ray EDS analysis (EDX). After appropriate metallographic preparation, the mechanical properties tested were Martens hardness (HM), indentation modulus (EIT), elastic index (ηIT), and Vickers hardness (HV). These properties were determined employing instrumented indentation testing (IIT) with a Vickers indenter. The results were statistically analyzed by unpaired t-test (α=0.05). There were no statistically significant differences evidenced in surface morphology and elemental content between the control and the experimental group. These two groups of brackets showed no statistically significant difference in surface morphology. Moreover, the mean values of HM, EIT, ηIT, and HV did not reach statistical significance between the groups (p>0.05). Under the limitations of this study, it may be concluded that the surface elemental content and microstructure as well as the evaluated mechanical properties of the Incognito™ lingual brackets remain unaffected by intraoral aging.
Sfondrini, Maria Francesca; Fraticelli, Danilo; Gandini, Paola
2013-01-01
Purpose. The aim of this study was to assess the effect of water and saliva contamination on the shear bond strength and failure site of orthodontic brackets and lingual buttons. Materials and Methods. 120 bovine permanent mandibular incisors were randomly divided into 6 groups of 20 specimens each. Both orthodontic brackets and disinclusion buttons were tested under three different enamel surface conditions: (a) dry, (b) water contamination, and (c) saliva contamination. Brackets and buttons were bonded to the teeth and subsequently tested using a Instron universal testing machine. Shear bond strength values and adhesive failure rate were recorded. Statistical analysis was performed using ANOVA and Tukey tests (strength values) and Chi squared test (ARI Scores). Results. Noncontaminated enamel surfaces showed the highest bond strengths for both brackets and buttons. Under water and saliva contamination orthodontic brackets groups showed significantly lower shear strengths than disinclusion buttons groups. Significant differences in debond locations were found among the groups under the various enamel surface conditions. Conclusions. Water and saliva contamination of enamel during the bonding procedure lowers bond strength values, more with orthodontic brackets than with disinclusion buttons. PMID:23762825
Evaluation of Antibacterial Effects of Silver-Coated Stainless Steel Orthodontic Brackets
Arash, Valiollah; Keikhaee, Fatemeh; Rajabnia, Ramazan; Khafri, Soraya; Tavanafar, Saeid
2016-01-01
Objectives: White spots and enamel demineralization around orthodontic brackets are among the most important complications resulting from orthodontic treatments. Since the antibacterial properties of metals and metallic particles have been well documented, the aim of this study was to assess the antibacterial effect of stainless steel orthodontic brackets coated with silver (Ag) particles. Materials and Methods: In this study, 40 standard metal brackets were divided into two groups of 20 cases and 20 controls. The brackets in the case group were coated with Ag particles using an electroplating method. Atomic force microscopy and scanning electron microscopy were used to assess the adequacy of the coating process. In addition, antibacterial tests, i.e., disk diffusion and direct contact tests were performed at three, six, 24, and 48 hours, and 15 and 30 days using a Streptococcus mutans strain. The results were analyzed using Student’s t-test and repeated measures ANOVA. Results: Analyses via SEM and AFM confirmed that excellent coatings were obtained by using an electroplating method. The groups exhibited similar behavior when subjected to the disk diffusion test in the agar medium. However, the bacterial counts of the Ag-coated brackets were, in general, significantly lower (P<0.001) than those of their non-coated counterparts. Conclusions: Brackets coated with Ag, via an electroplating method, exhibited antibacterial properties when placed in direct contact with Streptococcus mutans. This antibacterial effect persisted for 30 days after contact with the bacteria. PMID:27536328
Tozlu, Murat; Oztoprak, Mehmet Oguz; Arun, Tülin
2012-11-01
Laser use is effective in the debonding of ceramic brackets. However, a standardization of the laser debonding techniques used has not yet been implemented. The purpose of this study was to evaluate the effect of the time lag elapsed between lasing and shearing on debonding of ceramic brackets. One hundred polycrystalline ceramic brackets were placed on human premolar teeth, which were randomly divided into five groups of 20. One group was assigned as the control. The Er-YAG laser was applied on each bracket in four experimental groups at 5 W for 6 s with the scanning method. Debonding was performed 1 s, 18 s, 30 s, or 60 s after laser exposure. Shear bond strengths and adhesive remnant index scores were measured. Statistically significant difference was observed between the control and experimental groups when the data for the shear bond strengths was considered (p < 0.05). Adhesive remnant index scores of the groups were not statistically different (p > 0.05). Debonding ceramic brackets after 18 s when lased 6 s using an Er-YAG laser with the scanning method is safe and also suitable for clinical use since three brackets can be debonded at a time in succession.
Comparative assessment of different recycling methods of orthodontic brackets for clinical use.
de Oliveira Correia, Ayla M; de Souza Matos, Felipe; Pilli Jóias, Renata; de Mello Rode, Sigmar; Cesar, Paulo F; Paranhos, Luiz R
2017-06-01
This study aimed to assess bond strength of the resin/bracket interface, under in-vitro shear stress, of metal brackets recycled by different clinical protocols. Sixty stainless steel orthodontic brackets were bonded on acrylic resin. The Transbond XT™ resin was applied at the base of the bracket aided by a matrix, obtaining 1 mm of thickness, and photoactivated with a LED device (40 s; 500 mW/cm2). Samples were randomly divided into four groups (N.=15) according to the reconditioning/recycling protocol: aluminum oxide (AO) 90 µm; hydrofluoric acid 60 s (HA60); hydrofluoric acid 120 s (HA120); hydrofluoric acid 60 s + silane (HA60S). After recycling, the resin was applied at the base of the bracket for shear testing in a universal testing machine (0.5 mm/min). After reconditioning/recycling, the surfaces were analyzed by Scanning Electron Microscopy. Data obtained after the shear test were subjected to ANOVA and Tukey's test (P<0.05). The AO group presented higher values of shear bond strength compared to the other reconditioning/recycling protocols (P<0.05). The HA120 and HA60S groups presented statistically similar results, but HA120 presented strength below the recommended limit. The recycling technique by aluminum oxide sandblasting was more effective for reconditioning orthodontic brackets when compared to the other protocols. The reconditioning technique with 10% hydrofluoric acid followed by the application of silane bonding agent may be used as an alternative protocol.
Effect of bracket base design on shear bond strength to feldspathic porcelain
Dalaie, Kazem; Mirfasihi, Armin; Eskandarion, Solmaz; Kabiri, Sattar
2016-01-01
Objectives: This study sought to assess the effect of bracket base design on the shear bond strength (SBS) of the bracket to feldspathic porcelain. Materials and Methods: This in vitro, experimental study was conducted on 40 porcelain-fused-to-metal restorations and four different bracket base designs were bonded to these specimens. The porcelain surfaces were etched, silanized, and bonded to brackets. Specimens were thermocycler, incubated for 24 h and were subjected to SBS. Data were analyzed using Shapiro–Wilk test, Levene's test, one-way ANOVA, and Tukey's honest significant difference test. Adhesive remnant index was calculated and compared using Fisher's exact test. Results: One-way ANOVA showed that the SBS values were significantly different among the four groups (P < 0.001). Groups 1, 2, and 4 were not significantly different, but group 3 had significantly lower SBS (P < 0.001). Fractures mostly occurred at the porcelain-adhesive interface in Groups 1 and 2 while in Groups 3 and 4, bracket-adhesive and mixed failures were more common. Conclusion: The bracket base design significantly affects the SBS to feldspathic porcelain. PMID:27403052
Comparison of Shear Bond Strength of RMGI and Composite Resin for Orthodontic Bracket Bonding.
Yassaei, Soghra; Davari, Abdolrahim; Goldani Moghadam, Mahjobeh; Kamaei, Ahmad
2014-05-01
The aim of this study was to compare the shear bond strength (SBS) of resin modified glass ionomer (RMGI) and composite resin for bonding metal and ceramic brackets. Eighty-eight human premolars extracted for orthodontic purposes were divided into 4 groups (n=22). In groups 1 and 2, 22 metal and ceramic brackets were bonded using composite resin (Transbond XT), respectively. Twenty-two metal and ceramic brackets in groups 3 and 4, respectively were bonded using RMGI (Fuji Ortho LC, Japan). After photo polymerization, the teeth were stored in water and thermocycled (500 cycles between 5° and 55°). The SBS value of each sample was determined using a Universal Testing Machine. The amount of residual adhesive remaining on each tooth was evaluated under a stereomicroscope. Statistical analyses were done using two-way ANOVA. RMGI bonded brackets had significantly lower SBS value compared to composite resin bonded groups. No statistically significant difference was observed between metal and ceramic brackets bonded with either the RMGI or composite resin. The comparison of the adhesive remnant index (ARI) scores between the groups indicated that the bracket failure mode was significantly different among groups (P<0.001) with more adhesive remaining on the teeth bonded with composite resin. RMGIs have significantly lower SBS compared to composite resin for orthodontic bonding purposes; however the provided SBS is still within the clinically acceptable range.
Process qualification and testing of LENS deposited AY1E0125 D-bottle brackets.
Atwood, Clinton J.; Smugeresky, John E. (Sandia National Labs, Livermore,CA); Jew, Michael (Sandia National Labs, Livermore,CA); Gill, David Dennis; Scheffel, Simon
2006-11-01
The LENS Qualification team had the goal of performing a process qualification for the Laser Engineered Net Shaping{trademark}(LENS{reg_sign}) process. Process Qualification requires that a part be selected for process demonstration. The AY1E0125 D-Bottle Bracket from the W80-3 was selected for this work. The repeatability of the LENS process was baselined to determine process parameters. Six D-Bottle brackets were deposited using LENS, machined to final dimensions, and tested in comparison to conventionally processed brackets. The tests, taken from ES1E0003, included a mass analysis and structural dynamic testing including free-free and assembly-level modal tests, and Haversine shock tests. The LENS brackets performed with very similar characteristics to the conventionally processed brackets. Based on the results of the testing, it was concluded that the performance of the brackets made them eligible for parallel path testing in subsystem level tests. The testing results and process rigor qualified the LENS process as detailed in EER200638525A.
Al-Bazi, Samar M; Abbassy, Mona A; Bakry, Ahmed S; Merdad, Leena A; Hassan, Ali H
2016-01-01
The objectives of this study were to evaluate the effects of applying 0.50% chlorhexidine (CHX) gel using the dental drug delivery system (3DS) on salivary Streptococcus mutans (S. mutans) and on the surface topography of metal and ceramic orthodontic brackets. The study involved 20 orthodontic patients with high levels of salivary S. mutans. The patients were treated with professional mechanical tooth cleaning followed by application of 0.50% CHX using individual trays (3DS). Salivary S. mutans levels were repeatedly measured 1, 2, 4, and 8 weeks post-treatment. In vitro study utilized forty ceramic and metallic brackets that were immersed in 0.50% CHX gel for 10 min, whereas another untreated forty brackets served as controls. The frictional resistances of stainless steel wires to the brackets before and after CHX treatment were recorded using a universal testing machine. Scanning electron microscopy was used to compare changes in the surface topography of brackets. Statistical analyses were used to determine the effect of CHX on bacterial count and to evaluate the effect of CHX on frictional resistance. According to the results of this study, S. mutans levels were reduced significantly (P < 0.05). There were no significant changes in the frictional resistance and surface topography of brackets before or after application of CHX. (J Oral Sci 58, 35-42, 2016).
Arash, Valiollah; Javanmard, Saeed; Eftekhari, Zeinab; Rahmati-Kamel, Manouchehr; Bahadoram, Mohammad
2015-01-01
This research aimed to reduce the friction between the wire and brackets by Er:YAG laser. To measure the friction between the wires and brackets in 0° and 10° of wire angulations, 40 polycrystalline ceramic brackets (Hubit, South Korea) were divided into 8 study groups and irradiated by 100, 200, and 300 mj/s of Er:YAG laser power. Two groups of brackets were not irradiated. The friction between the wires and brackets was measured with universal testing machine (SANTAM) with a segment of .019 × .025 SS wire pulled out of the slot of bracket. ANOVA and t-test were used for analyzing the results. To evaluate the effect of the laser on surface morphology of the bracket, SEM evaluations were carried out. The mean frictional resistances between the brackets and wires with 0° of angulation by increasing the laser power decreased compared with control group, but, in 10° of angulation, the friction increased regardless of the laser power and was comparable to the friction of nonirradiated brackets. Furthermore, with each laser power, frictional resistance of brackets in 10° of angulation was significantly higher than 0° of angulation. These results were explained by SEM images too. PMID:26491447
Al Fakir, Hussam; Carey, Jason P; Melenka, Garrett W; Nobes, David S; Heo, Giseon; Major, Paul W
2014-09-01
Torque is applied to orthodontic brackets in order to alter the buccal-lingual angulation of a tooth. One factor that can affect torque is the ligation mode used to retain the archwire in the bracket slot. The objective of this study was to investigate the effects of stainless steel ligation on torque expression and bracket deformation. This study utilized 60 upper right central incisor Damon Q brackets and 60 Ormco Orthos Twin brackets. The brackets used in this study were subdivided into four groups: (1) Damon Q ligated with SS ligature; (2) Damon Q with the sliding bracket door; (3) Orthos Twin bracket ligated with SS wire; and (4) Orthos Twin ligated with elastic ties. All brackets were tested using an orthodontic torque simulating device that applied archwire rotation from 0° to 45°. All brackets ligated with stainless steel ties exhibited greater torque expression and less deformation than brackets without stainless steel ties. As well, Damon Q brackets exhibit less bracket deformation than Orthos Twin brackets. Stainless steel ties can reduce the amount of plastic deformation for both types of brackets used in this study. © 2014 British Orthodontic Society.
Pereira, Graziane Olímpio; Gimenez, Carla Maria Melleiro; Prieto, Lucas; Prieto, Marcos Gabriel do Lago; Basting, Roberta Tarkany
2016-01-01
ABSTRACT Objective: To evaluate stainless steel archwire static friction in active and passive self-ligating lingual and conventional brackets with second-order angulations. Methods: Two conventional lingual brackets for canines (STb light/Ormco; PSWb/Tecnident), and two self-ligating brackets, one active (In-Ovation L/GAC) and the other passive (3D/ Forestadent), were evaluated. A stainless steel archwire was used at 0°, 3° and 5° angulations. Metal ligatures, conventional elastic ligatures, and low friction elastic ligatures were also tested. A universal testing machine applied friction between brackets and wires, simulating sliding mechanics, to produce 2-mm sliding at 3 mm/minute speed. Results: Two-way analysis of variance demonstrated a significant effect of the interaction between brackets and angulations (p < 0.001). Tukey test indicated that the highest frictional resistance values were observed at 5° angulation for In-Ovation L, PSWb bracket with non conventional ligature, and STb bracket with metal ligature. As for 3D, PSWb with conventional or metal ligatures, and STb brackets with non conventional ligature, showed significantly lower static frictional resistance with 0° angulation. At 0° angulation, STb brackets with metal ties, In-Ovation L brackets and 3D brackets had the lowest frictional resistance. Conclusions: As the angulation increased from 0° to 3°, static friction resistance increased. When angulation increased from 3° to 5°, static friction resistance increased or remained the same. Self-ligating 3D and In-Ovation L brackets, as well as conventional STb brackets, seem to be the best option when sliding mechanics is used to perform lingual orthodontic treatment. PMID:27653262
Lens design based on lens form parameters using Gaussian brackets
NASA Astrophysics Data System (ADS)
Yuan, Xiangyu; Cheng, Xuemin
2014-11-01
The optical power distribution and the symmetry of the lens components are two important attributes that decide the ultimate lens performance and characteristics. Lens form parameters W and S are the key criteria describing the two attributes mentioned above. Lens components with smaller W and S will have a good nature of aberration balance and perform well in providing good image quality. Applying the Gaussian brackets, the two lens form parameters and the Seidel Aberration Coefficients are reconstructed. An initial lens structure can be analytically described by simultaneous equations of Seidel Aberration Coefficients and third-order aberration theory. Adding the constraints of parameters W and S in the solving process, a solution with a proper image quality and aberration distribution is achieved. The optical properties and image quality of the system based on the parameters W and S are also analyzed in this article. In the method, the aberration distribution can be controlled to some extent in the beginning of design, so that we can reduce some workload of optimization later.
The National Aquatic Resource Surveys (NARS) use probability-survey designs to assess the condition of the nation’s waters. In probability surveys (also known as sample-surveys or statistical surveys), sampling sites are selected randomly.
ERIC Educational Resources Information Center
Bailey, David H.
2000-01-01
Some of the most impressive-sounding criticisms of the conventional theory of biological evolution involve probability. Presents a few examples of how probability should and should not be used in discussing evolution. (ASK)
ERIC Educational Resources Information Center
Edwards, William F.; Shiflett, Ray C.; Shultz, Harris
2008-01-01
The mathematical model used to describe independence between two events in probability has a non-intuitive consequence called dependent spaces. The paper begins with a very brief history of the development of probability, then defines dependent spaces, and reviews what is known about finite spaces with uniform probability. The study of finite…
Shashidhar, E P; Sahitya, M; Sunil, T; Murthy, Anup R; Rani, M S
2015-01-01
Background: The purpose of this study was to evaluate and compare the adherence of microorganism to different types of brackets using the scanning electron microscope (SEM). A double-blinded study was undertaken to evaluate and adherence of microorganisms to different types of brackets using SEM. Materials and Methods: At random, 12 patients reporting for treatment to the department of Orthodontics VS Dental College and Hospital were selected. Four types of brackets were included in the present study stainless steel, titanium, composite, and ceramic. Brackets were bonded to teeth of the patient on all the four quadrants. The teeth included for bonding were lateral incisor, canine, first premolar, and second premolar. The brackets were left for 72 h. After 72 h brackets were debonded, and they were evaluated by SEM for adherence of microorganism in the slot and tie wings surface. The SEM images were graded, and the adherence of microorganism to the brackets in the surfaces and the four different quadrants were recorded. Results: There is a significant difference in adherence of microorganisms to the various types of brackets (P < 0.001) and the surfaces (P < 0.05) included in the study. However, there is no significance in the mean adherence of microorganisms in the different quadrants (P > 0.05) included in the study. The interaction of bracket/surface, bracket/quadrant, surface/quadrants was analyzed, there was no significance of comparison of bracket/surfaces/quadrant but the interaction of bracket/quadrant was found to be significant (<0.011). The interaction of bracket/surfaces/quadrant was also found to be significant (<0.003). Conclusion: The maximum adherence of microorganisms was observed with the composite bracket material and the least adherence of microorganisms was observed with the titanium bracket material. The adherence of microorganisms is relatively more in the slot area, when compare to the tie wings surface maximum adherence of microorganism is
Shashidhar, E P; Sahitya, M; Sunil, T; Murthy, Anup R; Rani, M S
2015-09-01
The purpose of this study was to evaluate and compare the adherence of microorganism to different types of brackets using the scanning electron microscope (SEM). A double-blinded study was undertaken to evaluate and adherence of microorganisms to different types of brackets using SEM. At random, 12 patients reporting for treatment to the department of Orthodontics VS Dental College and Hospital were selected. Four types of brackets were included in the present study stainless steel, titanium, composite, and ceramic. Brackets were bonded to teeth of the patient on all the four quadrants. The teeth included for bonding were lateral incisor, canine, first premolar, and second premolar. The brackets were left for 72 h. After 72 h brackets were debonded, and they were evaluated by SEM for adherence of microorganism in the slot and tie wings surface. The SEM images were graded, and the adherence of microorganism to the brackets in the surfaces and the four different quadrants were recorded. There is a significant difference in adherence of microorganisms to the various types of brackets (P < 0.001) and the surfaces (P < 0.05) included in the study. However, there is no significance in the mean adherence of microorganisms in the different quadrants (P > 0.05) included in the study. The interaction of bracket/surface, bracket/quadrant, surface/quadrants was analyzed, there was no significance of comparison of bracket/surfaces/quadrant but the interaction of bracket/quadrant was found to be significant (<0.011). The interaction of bracket/surfaces/quadrant was also found to be significant (<0.003). The maximum adherence of microorganisms was observed with the composite bracket material and the least adherence of microorganisms was observed with the titanium bracket material. The adherence of microorganisms is relatively more in the slot area, when compare to the tie wings surface maximum adherence of microorganism is observed in the upper left quadrant and least adherence
Nellore, Chaitanya; Karnati, Praveen Kumar Reddy; Thalapaneni, Ashok Kumar; Myla, Vijay Bhaskar; Ramyasree, Konda; Prasad, Mandava
2016-01-01
Introduction Orthodontists are commonly faced with the decision of what to do with loose brackets, and with inaccurately located brackets that need repositioning during treatment. One solution is to recycle the brackets. The potential effects of reconditioning a bracket are dependent upon many factors which may result in physical changes like alteration in slot tolerance, which may influence sliding mechanics by affecting frictional resistance. Aim To study and compare the dimensional changes in the bracket slot width and depth in reconditioned brackets from unused brackets under scanning electronic microscope and to study and compare any consequent effects on the static frictional resistance of stainless steel brackets after reconditioning and in unused brackets. Materials and Methods Dentarum manufactured 90 stainless steel central incisors edgewise brackets of size 0.22 X 0.030″ inch and 0° tip and 0°angulation were taken. 60 samples for measuring frictional resistance and 30 samples for measuring slot dimensions. Ortho organizers manufactured stainless steel arch wires 0.019 X 0.025″ straight lengths 60 in number were considered for measuring static frictional resistance. Results The mean slot width and depth of new brackets were 0.0251″ and 0.0471″, which exceeded the manufacturers reported nominal size of 0.022″ X 0.030″, by 0.003″ and 0.017″. The reconditioned brackets demonstrated a further increase in mean slot width and depth to 0.028″ and 0.0518″ that is by 0.0035″ and 0.0047″ which is statistically significant (p=0.001, 0.002). The mean static frictional forces of the reconditioned brackets was nearly similar to that of new brackets that is 0.3167N for reconditioned brackets and 0.2613 N for new brackets. Conclusion Although the reconditioning process results in physical changes to bracket structure this does not appear to result in significant effect on ex-vivo static frictional resistance. PMID:26894182
Modelling operations and security of cloud systems using Z-notation and Chinese Wall security policy
NASA Astrophysics Data System (ADS)
Basu, Srijita; Sengupta, Anirban; Mazumdar, Chandan
2016-11-01
Enterprises are increasingly using cloud computing for hosting their applications. Availability of fast Internet and cheap bandwidth are causing greater number of people to use cloud-based services. This has the advantage of lower cost and minimum maintenance. However, ensuring security of user data and proper management of cloud infrastructure remain major areas of concern. Existing techniques are either too complex, or fail to properly represent the actual cloud scenario. This article presents a formal cloud model using the constructs of Z-notation. Principles of the Chinese Wall security policy have been applied to design secure cloud-specific operations. The proposed methodology will enable users to safely host their services, as well as process sensitive data, on cloud.
Interaction of pitch and duration processing by non-musicians in reading musical notation.
Lee, Horng-Yih
2013-02-01
To study the relation of pitch and duration processing in reading musical notation, a Stroop-like task was used by 20 non-musicians. A probe display was presented before each target note. Participants were required to process the tonal and metric information of the probe and then to make a match or mismatch decision between probe and target. The target's color informed participants which dimension (pitch or duration) required analysis. The congruity of the irrelevant dimension of the target was manipulated to examine the effect on the relevant dimension. The interference effect of the irrelevant dimension on the relevant dimension was obvious for number of errors and reaction times. This result is consistent with pitch and duration being processed interdependently and reconciles with the theory of dynamic attention.
Vector/dyad notation in computer symbolic modeling of hybrid parameter mechanical systems
Barhorst, A.A.
1996-11-01
In this paper, computer symbolic algebra based algorithms written to take advantage of engineering vector notation, as applied to hybrid parameter mechanical systems, are demonstrated. The symbolic manipulation tools are utilized to implement a hybrid parameter system modeling algorithm previously developed by the author. The modeling algorithm produces minimal holonomic and nonholonomic equations of motion for hybrid systems of any continuum dimension and kinematic topology. Boundary conditions are rigorously supplied by the modeling method. The system model presented as an example is a hybrid parameter planar two link model of a robot manipulator. A complete analysis from model to simulation and animation in a Mathematica notebook is presented. The modeling tools presented herein are applicable for researchers, practicing engineers, and students in advanced dynamic system modeling and control courses.
Creating interactive, web-based and data-enriched maps with the Systems Biology Graphical Notation.
Junker, Astrid; Rohn, Hendrik; Czauderna, Tobias; Klukas, Christian; Hartmann, Anja; Schreiber, Falk
2012-03-01
The Systems Biology Graphical Notation (SBGN) is an emerging standard for the uniform representation of biological processes and networks. By using examples from gene regulation and metabolism, this protocol shows the construction of SBGN maps by either manual drawing or automatic translation using the tool SBGN-ED. In addition, it discusses the enrichment of SBGN maps with different kinds of -omics data to bring numerical data into the context of these networks in order to facilitate the interpretation of experimental data. Finally, the export of such maps to public websites, including clickable images, supports the communication of results within the scientific community. With regard to the described functionalities, other tools partially overlap with SBGN-ED. However, currently, SBGN-ED is the only tool that combines all of these functions, including the representation in SBGN, data mapping and website export. This protocol aims to assist scientists with the step-by-step procedure, which altogether takes ∼90 min.
Exploring the association between visual perception abilities and reading of musical notation.
Lee, Horng-Yih
2012-06-01
In the reading of music, the acquisition of pitch information depends primarily upon the spatial position of notes as well as upon an individual's spatial processing ability. This study investigated the relationship between the ability to read single notes and visual-spatial ability. Participants with high and low single-note reading abilities were differentiated based upon differences in musical notation-reading abilities and their spatial processing; object recognition abilities were then assessed. It was found that the group with lower note-reading abilities made more errors than did the group with a higher note-reading abilities in the mental rotation task. In contrast, there was no apparent significant difference between the two groups in the object recognition task. These results suggest that note-reading may be related to visual spatial processing abilities, and not to an individual's ability with object recognition.
OMR of early plainchant manuscripts in square notation: a two-stage system
NASA Astrophysics Data System (ADS)
Ramirez, Carolina; Ohya, Jun
2011-01-01
While Optical Music Recognition (OMR) of modern printed and handwritten documents is considered a solved problem, with many commercial systems available today, the OMR of ancient musical manuscripts still remains an open problem. In this paper we present a system for the OMR of degraded western plainchant manuscripts in square notation from the XIV to XVI centuries. The system has two main blocks, the first one deals with symbol extraction and recognition, while the second one acts as an error detection stage for the first block outputs. For symbol extraction we use widely known image-processing techniques, such as Sobel filtering and Hough Transform, and SVM for classification. The error detection stage is implemented with a hidden Markov model (HMM), which takes advantage of a priori knowledge for this specific kind of music.
Musical training effect on reading musical notation: evidence from event-related potentials.
Lee, Horng-Yih; Lei, Sot-Fu
2012-08-01
Musical training enhances a range of non-musical cognitive functions, including visuospatial abilities. The aim of this study was to explore which event-related potential (ERP) components were enhanced or reduced as a result of musical training. Both electrophysiological and behavioral methods were used to compare musicians and non-musicians in the processing of pitch and duration when reading single musical notes. It was observed that in the early stage of note reading, the musician/non-musician differences emerged in the latency range of the N1 and N2. The N1 component was enhanced; in contrast, the N2 component was reduced in musicians. It is possible that musicians receive auditory meanings from visual music notations, so they therefore did not find it necessary to spend more resources on executing spatial attention than non-musicians do during pitch processing.
Dynamical Simulation of Probabilities
NASA Technical Reports Server (NTRS)
Zak, Michail
1996-01-01
It has been demonstrated that classical probabilities, and in particular, probabilistic Turing machine, can be simulated by combining chaos and non-Lipschitz dynamics, without utilization of any man-made devices(such as random number generators). Self-orgainizing properties of systems coupling simulated and calculated probabilities and their link to quantum computations are discussed. Special attention was focused upon coupled stochastic processes, defined in terms of conditional probabilities, for which joint probability does not exist. Simulations of quantum probabilities are also discussed.
Dynamical Simulation of Probabilities
NASA Technical Reports Server (NTRS)
Zak, Michail
1996-01-01
It has been demonstrated that classical probabilities, and in particular, probabilistic Turing machine, can be simulated by combining chaos and non-Lipschitz dynamics, without utilization of any man-made devices(such as random number generators). Self-orgainizing properties of systems coupling simulated and calculated probabilities and their link to quantum computations are discussed. Special attention was focused upon coupled stochastic processes, defined in terms of conditional probabilities, for which joint probability does not exist. Simulations of quantum probabilities are also discussed.
Meyer, Rudolf
2008-01-01
The Tip-Edge bracket was invented by Dr. P.C. Kesling (La Porte, Indiana, U.S.A.) in 1986. It introduced differential tooth movement within a modified Straight-Wire bracket system. The new Tip-Edge Plus bracket, first introduced in 2003, now uses superelastic Ni-Ti archwires (Deep Tunnel or Uprighting Wires) in Stage III instead of the Side-Winder springs for tip and torque. With Tip-Edge Plus, the average treatment time for extraction and non-extraction cases is 16 months, with 4 to 6 main archwires. Headgear, bite turbos and mini-implants are not required. The comfort for the patient and operator is increased, with less adjustments and shorter treatment time, resulting in a zero tolerance finish. This is because of the unique bracket architecture, which allows controlled tipping in one direction, while boosting anchorage in the other, with three-dimensional root control at the finish. Tip-Edge Plus Orthodontics is the fixed appliance of the 21st century and is in the education programmes of more than 55 dental shools worldwide.
Cacciafesta, Vittorio; Sfondrini, M Francesca
2010-01-01
In the past 10 years, self-ligating brackets have captured the interest of many clinicians and enjoyed increasing popularity. These brackets have been developed to overcome the disadvantages of stainless steel or elastomeric ligatures in terms of ergonomics, efficiency, deformation, discoloration, plaque accumulation, and friction. A self-ligating bracket does not require any type of ligature because it is has a mechanical device that opens and closes the edgewise slot. Secure archwire engagement may be accomplished by a built-in clip. Depending on the interaction between the bracket and archwire, self-ligating brackets can be active and passive. The aim of this article is to describe a new active self-ligating bracket system designed to noticeably reduce the amount of friction that normally originates from archwire-slot interaction, particularly during the correction of horizontal and vertical discrepancies. © 2010 BY QUINTESSENCE PUBLISHING CO, INC.
ERIC Educational Resources Information Center
Dania, Aspasia; Tyrovola, Vasiliki; Koutsouba, Maria
2017-01-01
The aim of this paper is to present the design and evaluate the impact of a Laban Notation-based method for Teaching Dance (LANTD) on novice dancers' performance, in the case of Greek traditional dance. In this research, traditional dance is conceived in its "second existence" as a kind of presentational activity performed outside its…
ERIC Educational Resources Information Center
Kell, Clare; Sweet, John
2017-01-01
This paper shows how peer observation of learning and teaching (POLT) discussions can be augmented through the use of a dynamic visual notation that makes visible for interpretation, elements of teacher-learner and learner-earner nonverbal interactions. Making visible the nonverbal, physical, spatial and kinesics (eye-based) elements of…
ERIC Educational Resources Information Center
Kell, Clare; Sweet, John
2017-01-01
This paper shows how peer observation of learning and teaching (POLT) discussions can be augmented through the use of a dynamic visual notation that makes visible for interpretation, elements of teacher-learner and learner-earner nonverbal interactions. Making visible the nonverbal, physical, spatial and kinesics (eye-based) elements of…
ERIC Educational Resources Information Center
Watson, Kevin E.
2010-01-01
The purpose of the present study was to investigate the effects of aural versus notated pedagogical materials on achievement and self-efficacy in instrumental jazz improvisation performance. A secondary purpose of this study was to investigate how achievement and self-efficacy may be related to selected experience variables. The sample for the…
ERIC Educational Resources Information Center
Watson, Kevin E.
2010-01-01
The purpose of the present study was to investigate the effects of aural versus notated pedagogical materials on achievement and self-efficacy in instrumental jazz improvisation performance. A secondary purpose of this study was to investigate how achievement and self-efficacy may be related to selected experience variables. The sample for the…
ERIC Educational Resources Information Center
Fredrick, Wayne C.; And Others
Seventy-two grade 8 students were randomly assigned to one of four experimental groups. One group studied five programed lessons in structural grammar, written without use of symbols or diagrams. A second group studied the same content presented with a symbolic notation to represent the grammar concepts. A third group studied the same content…
In vitro study of color stability of polycrystalline and monocrystalline ceramic brackets
de Oliveira, Cibele Braga; Maia, Luiz Guilherme Martins; Santos-Pinto, Ary; Gandini Júnior, Luiz Gonzaga
2014-01-01
Objective The aim of this in vitro study was to analyze color stability of monocrystalline and polycrystalline ceramic brackets after immersion in dye solutions. Methods Seven ceramic brackets of four commercial brands were tested: Two monocrystalline and two polycrystalline. The brackets were immersed in four dye solutions (coffee, red wine, Coke and black tea) and in artificial saliva for the following times: 24 hours, 7, 14 and 21 days, respectively. Color changes were measured by a spectrophotometer. Data were assessed by Multivariate Profile Analysis, Analysis of Variance (ANOVA) and Multiple Comparison Tests of means. Results There was a perceptible change of color in all ceramic brackets immersed in coffee (ΔE* Allure = 7.61, Inspire Ice = 6.09, Radiance = 6.69, Transcend = 7.44), black tea (ΔE* Allure = 6.24, Inspire Ice = 5.21, Radiance = 6.51, Transcend = 6.14) and red wine (ΔE* Allure = 6.49, Inspire Ice = 4.76, Radiance = 5.19, Transcend = 5.64), but no change was noticed in Coke and artificial saliva (ΔE < 3.7). Conclusion Ceramic brackets undergo color change when exposed to solutions of coffee, black tea and red wine. However, the same crystalline structure, either monocrystalline or polycrystalline, do not follow the same or a similar pattern in color change, varying according to the bracket fabrication, which shows a lack of standardization in the manufacturing process. Coffee dye produced the most marked color changes after 21 days of immersion for most ceramic brackets evaluated. PMID:25279530
Pereira, Tatiana Bahia Junqueira; Jansen, Wellington Corrêa; Pithon, Matheus Melo; Souki, Bernardo Quiroga; Tanaka, Orlando Motohiro; Oliveira, Dauro Douglas
2013-08-01
The objective of this study was to test the effects of enamel deproteinization on bracket bonding with conventional and resin-modified glass ionomer cement (RMGIC). One hundred premolars, extracted for orthodontic reasons, were divided into five groups (n = 20). Group 1 (control): enamel was etched with 35 per cent phosphoric acid, a thin layer of adhesive was applied, and the brackets were bonded with Transbond XT. Group 2: enamel was etched with 10 per cent polyacrylic acid and the brackets were bonded with conventional glass ionomer cement (GIC). Group 3: enamel was treated with 5.25 per cent NaOCl, etched with 10 per cent polyacrylic acid, and the brackets were bonded with conventional GIC. Group 4: enamel was etched with 10 per cent polyacrylic acid and the brackets were bonded with RMGIC. Group 5: enamel was treated with 5.25 per cent NaOCl, etched with 10 per cent polyacrylic acid, and the brackets were bonded with RMGIC. The teeth were stored in distilled water for 24 hours before they were submitted to shear testing. The results demonstrated that bond strength values of group 1 (17.08 ± 6.39 MPa) were significantly higher in comparison with the other groups. Groups 2 (3.43 ± 1.94 MPa) and 3 (3.92 ± 1.57 MPa) presented values below the average recommended in the literature. With regard to adhesive remnant index, the groups in which the enamel was treated with NaOCl showed a behaviour similar to that of the resin composite. It is conclude with enamel treatment with NaOCl increased bonding strength of brackets bonded with GIC and RMGIC, but increased bond strength was not statistically significant when compared to the untreated groups.
SHEAR BOND STRENGTH OF ORTHODONTIC BRACKETS TO ENAMEL UNDER DIFFERENT SURFACE TREATMENT CONDITIONS
Pithon, Matheus Melo; de Oliveira, Márlio Vinícius; Ruellas, Antonio Carlos de Oliveira; Bolognese, Ana Maria; Romano, Fábio Lourenço
2007-01-01
The purpose of the present study was to evaluate the shear bond strength to enamel and the adhesive remnant index (ARI) of both metallic and polycarbonate brackets bonded under different conditions. Ninety bovine permanent mandibular incisors were embedded in acrylic resin using PVC rings as molds and assigned to 6 groups (n=15). In Groups 1 (control) and 3, metallic and polycarbonate orthodontic brackets were, respectively, bonded to the enamel surfaces using Transbond XT composite according to the manufacturer's recommendations. In Groups 2 and 4, both types of brackets were bonded to enamel with Transbond XT composite, but XT primer was replaced by the OrthoPrimer agent. In Groups 5 and 6, the polycarbonate bracket bases were sandblasted with 50-μm aluminum-oxide particle stream and bonded to the enamel surfaces prepared under the same conditions described in Groups 3 and 4, respectively. After bonding, the specimens were stored in distilled water at 37°C for 24 hours and then submitted to shear bond strength test at a crosshead speed of 0.5 mm/min. The results (MPa) showed no statistically significant difference between Groups 4 and 6 (p>0.05). Likewise, no statistically significant differences (p>0.05) were found among Groups 1, 2, and 5, although their results were significantly lower than those of Groups 4 and 6 (p<0.05). Group 3 had statistically significant lower bond strength than Groups 2, 4, and 6, but no statistically significant differences were found on comparison to Groups 1 and 5. A larger number of fractures at the bracket/composite interface were evidenced by the ARI scores. OrthoPrimer bonding agent yielded higher bond strength in the groups using either conventional or sandblasted polycarbonate brackets, which was not observed in the groups using metallic brackets. PMID:19089115
A novel biomimetic orthodontic bonding agent helps prevent white spot lesions adjacent to brackets.
Manfred, Lauren; Covell, David A; Crowe, Jennifer J; Tufekci, Eser; Mitchell, John C
2013-01-01
To compare changes in enamel microhardness adjacent to orthodontic brackets after using bonding agents containing various compositions of bioactive glass compared to a traditional resin adhesive following a simulated caries challenge. Extracted human third molars (n = 10 per group) had orthodontic brackets bonded using one of four novel bioactive glass (BAG)-containing orthodontic bonding agents (BAG-Bonds) or commercially available Transbond-XT. The four new adhesives contained BAG in varying percentages incorporated into a traditional resin monomer mixture. Teeth were cycled through low-pH demineralizing and physiologic-pH remineralizing solutions once each day over 14 days. Microhardness was measured on longitudinal sections of the teeth 100, 200, and 300 µm from the bracket edge and beneath the brackets, at depths of 25 to 200 µm from the enamel surface. Normalized hardness values were compared using three-way analysis of variance. Significantly less reduction in enamel microhardness was found with the experimental adhesives at depths of 25 and 50 µm at all distances from the bracket edge. In all groups, there were no significant changes in enamel microhardness past 125-µm depth. Results varied with the different BAG-Bonds, with 81BAG-Bond showing the smallest decrease in enamel microhardness. The BAG-Bonds tested in this study showed a reduction in the amount of superficial enamel softening surrounding orthodontic brackets compared to a traditional bonding agent. The results indicate that clinically, BAG-Bonds may aid in maintaining enamel surface hardness, therefore helping prevent white spot lesions adjacent to orthodontic brackets.
Kao, Chia-Tze; Guo, Jia-Uei; Huang, Tsui-Hsien
2011-05-01
Titanium nitride (TiN) plating is a method to prevent metal corrosion and can increase the surface smoothness. The purpose of this study was to evaluate the friction forces between the orthodontic bracket, with or without TiN plating, and stainless steel wire after it was corroded in fluoride-containing solution. In total, 540 metal brackets were divided into a control group and a TiN-coated experimental group. The electrochemical corrosion was performed in artificial saliva with 1.23% acidulated phosphate fluoride (APF) as the electrolytes. Static and kinetic friction were measured by an EZ-test machine (Shimadazu, Tokyo, Japan) with a crosshead speed of 10 mm per minute over a 5-mm stretch of stainless steel archwire. The data were analyzed by using unpaired t test and analysis of variance (ANOVA). Both the control and TiN-coated groups' corrosion potential was higher with 1.23% APF solution than with artificial solution (P <0.05). In brackets without corrosion, both the static and kinetic friction force between the control and TiN-coated brackets groups showed a statistically significant difference (P <0.05). In brackets with corrosion, the control group showed no statistical difference on kinetic or static friction. The TiN-coated brackets showed a statistical difference (P <0.05) on kinetic and static friction in different solutions. TiN-coated metal brackets, with corrosion or without corrosion, cannot reduce the frictional force. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.
Fischer-Brandies, H; Orthuber, W; Es-Souni, M; Meyer, S
2000-01-01
The aim of the study was to investigate the influence of cross section, edge geometry and structural hardness on torque transmission between square wire and bracket. For this purpose, 5 different brands of stainless steel square wire in 3 dimensions (0.016" x 0.016", 0.016" x 0.022" and 0.017" x 0.025") were inserted into edgewise brackets with a slot size of 0.018" and loaded with different torques (1 and 3 Ncm). The slot and wire geometries were analyzed by computer on ground specimens before and after loading. In addition, the Vickers hardness and micro-hardness of the unstressed and stressed metal surfaces were determined. While the slot size was very accurately maintained, the wire dimensions deviated downwards by an average of 10%. Torque transmission led to notching and bending-up phenomena on the bracket slot flanks. A torque loading of 3 Ncm increased the torque play of 0.016" x 0.022" wires by 3.6 degrees, and of 0.017" x 0.025" wires by 3.7 degrees. In the case of 0.016" x 0.016" wires, an effective torque transmission was no longer possible. The average Vickers hardness of the wires was 533 kp/mm2, and that of the brackets 145 kp/mm2. The micro-hardness in the deformation area of stressed internal slot walls increased with increasing load transmission from 204 to 338 kp/mm2. As a result of excessively small wire dimensions and plastic deformation of the brackets, a relatively large torque play occurs. Deformation and notching in the area of the internal slot walls are inconsistent with demands for recycling brackets. A standardization of bracket wire systems stating the actual torque play would be desirable.
Light energy attenuation through orthodontic ceramic brackets at different irradiation times.
Santini, Ario; Tiu, Szu Hui; McGuinness, Niall J P; Aldossary, Mohammed Saeed
2016-09-01
To evaluate the total light energy (TLE) transmission through three types of ceramic brackets with, bracket alone and with the addition of orthodontic adhesive, at different exposure durations, and to compare the microhardness of the cured adhesive. Three different makes of ceramic brackets, Pure Sapphire(M), Clarity™ ADVANCED(P) and Dual Ceramic(P) were used. Eighteen specimens of each make were prepared and allocated to three groups (n = 6). MARC(®)-resin calibrator was used to determine the light curing unit (LCU) tip irradiance (mW/cm(2)) and TLE (J/cm(2)) transmitted through the ceramic brackets, and through ceramic bracket plus Transbond™ XT Light Cure Adhesive, for 5, 10 and 20 s. Vickers-hardness values at the bottom of the cured adhesive were determined. Statistical analysis used one-way analysis of variance (ANOVA); P = 0.05. TLE transmission rose significantly among all samples with increasing exposure durations. TLE reaching the adhesive- enamel interface was less than 10 J/cm(2), and through monocrystalline and polycrystalline ceramic brackets was significantly different (P < 0.05). Pure Sapphire(M) showed the highest amount of TLE transmission and Vickers-hardness values for 5, 10 and 20 s. Following manufacturer's recommendations, insufficient TLE may be delivered to the adhesive: increasing the exposure durations may be required when adhesive is cured through ceramic brackets. Clinicians are advised to measure the tip irradiance of their LCUs and increase curing time beyond 5 s. Orthodontic clinicians should understand the type of light curing device and the orthodontic adhesive used in their practice.
Canbek, Kerem; Karbach, Mareike; Gottschalk, Franziska; Erbe, Christina; Wehrbein, Heinrich
2013-03-01
Bovine teeth are commonly used as substitutes for human teeth in scientific investigations. The present study was performed in vitro with the objective of comparing bovine and human enamel subjected to thermocycling for microleakage beneath metal brackets. A total of 50 bovine and human teeth (25 per group) void of defects or carious decay were extracted and stored in chloramine B (0.5%). A light-curing adhesive (Transbond™ XT) was used as instructed by the manufacturer (3M Unitek, Monrovia, CA, USA) to bond a metal bracket (discovery®; Dentaurum, Ispringen, Germany) to the surface of each tooth following 30 s of enamel etching (phosphoric acid 35%). After 24 h of dye penetration in methylene blue (0.5%), the cervical and incisal bracket surfaces were analyzed by light microscopy for excess bonding material, dye penetration, and microleakage at the bracket-adhesive and adhesive-enamel interfaces. Staining and evaluation was repeated after thermocycling (5000 cycles at 5/55 °C). Before thermocycling, the number of human teeth showing marginal gaps was one-third the number of bovine teeth (p<0.001). After thermocycling, the distribution of gaps was similar (p=0.180). The adhesive-enamel interface was most frequently affected (on 74% of human and 64% of bovine teeth). No dye penetration in either group after examining a horizontal slice through the bracket basis was observed. Immediately after bonding, less microleakage was observed around the base of metal brackets on human than bovine teeth. These marginal gaps were, however, superficial in both groups, none of them involving deep penetration of dye under the bracket base.
Ion release from orthodontic brackets in 3 mouthwashes: an in-vitro study.
Danaei, Shahla Momeni; Safavi, Afsaneh; Roeinpeikar, S M Mehdi; Oshagh, Morteza; Iranpour, Shiva; Omidkhoda, Maryam; Omidekhoda, Maryam
2011-06-01
Stainless steel orthodontic brackets can release metal ions into the saliva. Fluoridated mouthwashes are often recommended to orthodontic patients to reduce the risk of white-spot lesions around their brackets. However, little information is available regarding the effect of different mouthwashes in ion release of orthodontic brackets. The purpose of this study was to measure the amount of metal ion release from orthodontic brackets when kept in different mouthwashes. One hundred sixty stainless steel brackets (0.022-in, 3M Unitek, Monrovia, Calif) were divided randomly into 4 equal groups and immersed in Oral B (Procter & Gamble, Weybridge, United Kingdom), chlorhexidine (Shahdaru Labratories, Tehran, Iran), and Persica (Poursina Pharmaceutical Laboratories, Tehran, Iran) mouthwashes and distilled deionized water and incubated at 37°C for 45 days. Nickel, chromium, iron, copper, and manganese released from the orthodontic brackets were measured with an inductively coupled plasma spectrometer. For statistical analysis, 1-way analysis of variance (ANOVA) and the Duncan multiple-range tests were used. The results showed that ion release in deionized water was significantly (P <0.05) higher than in the 3 mouthwashes. Higher ion release was found with chlorhexidine compared with the other 2 mouthwashes. There was no significant difference (P >0.05) in nickel, chromium, iron, and copper ion release in the Oral B and Persica mouthwashes. The level of manganese release was significantly different in all 4 groups. If ion release is a concern, Oral B and Persica mouthwashes might be better options than chlorhexidine for orthodontic patients with stainless steel brackets. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.
Chalipa, Javad; Jalali, Yasamin Farajzadeh; Gorjizadeh, Fatemeh; Baghaeian, Pedram; Hoseini, Mohammad Hashem
2016-01-01
Objectives: The aim of this study was to evaluate the effect of conventional and high-power light emitting diode (LED) light curing units on shear bond strength (SBS) of metal and ceramic brackets to tooth surface. Materials and Methods: Forty sound bovine maxillary central incisors were used for the study. The teeth were divided into four groups (n=10). Teeth surfaces were etched with 37% phosphoric acid for 20 seconds. After applying a uniform layer of adhesive primer on the etched enamel, composite was placed on the base of brackets. The samples were light cured according to the manufacturer’s instructions and thermocycled. The SBS was measured. The failure mode was scored using the adhesive remnant index (ARI). Results: The mean SBS of samples in groups A (high-power LED, metal bracket), B (high-power LED, ceramic bracket), C (conventional LED, metal bracket) and D (conventional LED, ceramic bracket) was 23.1±3.69, 10.7±2.06, 24.92±6.37 and 10.74±3.18MPa, respectively. The interaction effect of type of LED unit (high-power/conventional) and bracket type on SBS was not statistically significant (P=0.483). In general, type of LED unit did not affect SBS. Type of bracket significantly affected SBS (P<0.001). The ARI score was not significantly influenced by the interaction between the type of LED unit and bracket. Conclusions: The obtained SBS is the same for both bracket types by use of high-power and conventional LED light curing units. Regardless of the type of LED unit, SBS of ceramic brackets was significantly lower than that of metal brackets. PMID:28243304
Uysal, Tancan; Ustdal, Ayca; Kurt, Gokmen
2010-04-01
The aim of this in vitro study was to evaluate the shear bond strength (SBS) of different metallic and ceramic bracket bonding combinations using self-etching primers (SEPs). Eighty freshly extracted human premolar teeth were randomly divided into four equal groups for bonding with ceramic or metallic brackets as follows: group 1, metallic brackets bonded with conventional acid etching; group 2, metallic brackets bonded with Transbond Plus Self-Etching primer (TPSEP); group 3, ceramic brackets bonded as per group 1; group 4, ceramic brackets bonded as per group 2. The SBS of these brackets was measured and recorded in megapascals (MPa). The adhesive remnant index (ARI) scores were determined after bracket failure. Data were analyzed with the analysis of variance, Tukey, and chi-square tests. The bond strength of group 3 (mean: 36.7 +/- 11.8 MPa) was significantly higher than group 4 (mean: 26.6 +/- 8.9 MPa; P < 0.05), group 1 (mean: 25.5 +/- 5.1 MPa; P < 0.01), and group 2 (mean: 22.9 +/- 7.3 MPa; P < 0.001). No significant differences in debond locations were found among the groups (P > 0.05). Compared with conventional acid etching, SEPs significantly decreased the SBS of ceramic orthodontic brackets.
NASA Astrophysics Data System (ADS)
Huda, M. M.; Siregar, E.; Ismah, N.
2017-08-01
Stainless steel bracket slot deformation ffects the force applied to teeth and it can impede tooth movement and prolong orthodontic treatment time. The aim of this study is to determine the slot deformation due to torque of a 0.021 × 0.025 inch Beta Titanium wire with a torsional angle of 30° and 45° for five different bracket brands: y, 3M, Biom, Versadent, Ormco, and Shinye. The research also aims to compare the deformation and amount of torque among all five bracket brands at torsional angles of 30° and 45°. Fifty stainless steel edgewise brackets from the five bracket group brands (n=10) were attached to acrylic plates. The bracket slot measurements were carried out in two stages. In the first stage, the, deformation was measured by calculating the average bracket slot height using a stereoscopy microscope before and after application of torque. In the second stage, the torque was measured using a torque measurement apparatus. The statistical analysis shows that slot deformations were found on all five bracket brands with a clinical permanent deformation on the Biom (2.79 μm) and Shinye (2.29 μm) brackets. The most torque was observed on the 3M bracket, followed by the Ormco, Versadent, Shinye, and Biom brackets. When the brands were compared, a correlation between bracket slot deformation and the amount of torque was found, but the correlation was not statistically significant for the 3M and Ormco brackets and the Biom and Shinye brackets. There is a difference in the amount of torque between the five brands with a torsional angle of 30° (except the 3M and Ormco brackets) and those with a torsional angle of 45°. The composition of the metal and the manufacturing process are the factors that influence the occurrence of bracket slot deformation and the amount of torque. A manufacturing process using metal injection molding (MIM) and metal compositions of AISI 303 and 17-4 PH stainless steel reduce the risk of deformation.
Carneiro, Grace Kelly Martins; Roque, Juliano Alves; Segundo, Aguinaldo Silva Garcez; Suzuki, Hideo
2015-01-01
OBJECTIVE: The aim of this study was to assess whether repetitive opening and closure of self-ligating bracket clips can cause plastic deformation of the clip. METHODS: Three types of active/interactive ceramic self-ligating brackets (n = 20) were tested: In-Ovation C, Quicklear and WOW. A standardized controlled device performed 500 cycles of opening and closure movements of the bracket clip with proper instruments and techniques adapted as recommended by the manufacturer of each bracket type. Two tensile tests, one before and one after the repetitive cycles, were performed to assess the stiffness of the clips. To this end, a custom-made stainless steel 0.40 x 0.40 mm wire was inserted into the bracket slot and adapted to the universal testing machine (EMIC DL2000), after which measurements were recorded. On the loading portion of the loading-unloading curve of clips, the slope fitted a first-degree equation curve to determine the stiffness/deflection rate of the clip. RESULTS: The results of plastic deformation showed no significant difference among bracket types before and after the 500 cycles of opening and closure (p = 0.811). There were significant differences on stiffness among the three types of brackets (p = 0.005). The WOW bracket had higher mean values, whereas Quicklear bracket had lower values, regardless of the opening/closure cycle. CONCLUSION: Repetitive controlled opening and closure movements of the clip did not alter stiffness or cause plastic deformation. PMID:26352844
Carneiro, Grace Kelly Martins; Roque, Juliano Alves; Segundo, Aguinaldo Silva Garcez; Suzuki, Hideo
2015-01-01
The aim of this study was to assess whether repetitive opening and closure of self-ligating bracket clips can cause plastic deformation of the clip. Three types of active/interactive ceramic self-ligating brackets (n = 20) were tested: In-Ovation C, Quicklear and WOW. A standardized controlled device performed 500 cycles of opening and closure movements of the bracket clip with proper instruments and techniques adapted as recommended by the manufacturer of each bracket type. Two tensile tests, one before and one after the repetitive cycles, were performed to assess the stiffness of the clips. To this end, a custom-made stainless steel 0.40 x 0.40 mm wire was inserted into the bracket slot and adapted to the universal testing machine (EMIC DL2000), after which measurements were recorded. On the loading portion of the loading-unloading curve of clips, the slope fitted a first-degree equation curve to determine the stiffness/deflection rate of the clip. The results of plastic deformation showed no significant difference among bracket types before and after the 500 cycles of opening and closure (p = 0.811). There were significant differences on stiffness among the three types of brackets (p = 0.005). The WOW bracket had higher mean values, whereas Quicklear bracket had lower values, regardless of the opening/closure cycle. Repetitive controlled opening and closure movements of the clip did not alter stiffness or cause plastic deformation.
NASA Astrophysics Data System (ADS)
Marshman, Emily; Singh, Chandralekha
2017-03-01
A solid grasp of the probability distributions for measuring physical observables is central to connecting the quantum formalism to measurements. However, students often struggle with the probability distributions of measurement outcomes for an observable and have difficulty expressing this concept in different representations. Here we first describe the difficulties that upper-level undergraduate and PhD students have with the probability distributions for measuring physical observables in quantum mechanics. We then discuss how student difficulties found in written surveys and individual interviews were used as a guide in the development of a quantum interactive learning tutorial (QuILT) to help students develop a good grasp of the probability distributions of measurement outcomes for physical observables. The QuILT strives to help students become proficient in expressing the probability distributions for the measurement of physical observables in Dirac notation and in the position representation and be able to convert from Dirac notation to position representation and vice versa. We describe the development and evaluation of the QuILT and findings about the effectiveness of the QuILT from in-class evaluations.
Friction behavior of self-ligating and conventional brackets with different ligature systems.
Szczupakowski, Alexandra; Reimann, Susanne; Dirk, Cornelius; Keilig, Ludger; Weber, Anna; Jäger, Andreas; Bourauel, Christoph
2016-07-01
Self-ligating brackets are widely believed to offer better clinical efficiency and, in particular, less friction. Thus, the goal of this in vitro investigation was to assess the friction behavior of different bracket/archwire/ligature combinations during simulated canine retraction. An important aspect of this work was to determine whether conventional bracket systems behave differently in passive or active self-ligating brackets used with a Slide™ ligature, an elastic ligature, or a steel ligature. Three conventional (Contour, Class One; Discovery(®), Dentaurum; Mystique MB, GAC) and six self-ligating (Carriere SL, Class One; Clarity™ SL, 3M Unitek; Damon3, Ormco; In-Ovation(®) C, GAC; Speed Appliance, Speed System™; QuicKlear(®), Forestadent(®)) bracket systems were analyzed. All brackets featured a 0.022″ slot (0.56 mm). Each conventional system was tested with a steel ligature (0.25 mm; Remanium(®), Dentaurum), an elastic ligature (1.3 mm in diameter; Dentalastics, Dentaurum), and a modified elastic ligature (Slide™; Leone(®)). Each combination was used with four archwires, including rectangular stainless steel (0.46 × 0.64 mm, 0.018 × 0.025″, Dentaurum), rectangular nickel-titanium with Teflon coating (0.46 × 0.64 mm, 0.018 × 0.025″, Forestadent(®)), round coaxial nickel-titanium (0.46 mm, 0.018″, Speed), and half-round/half-square (D-profile) stainless steel (0.46 mm, 0.018″, Speed). In the orthodontic measurement and simulation system (OMSS), retraction of a canine was simulated on a Frasaco model replicated in resin. Based on the force systems, the respective friction values were determined. For each combination of materials, five brackets of the same type were tested and five single measurements performed. Friction values were found to vary distinctly with the different combinations, modifiers being the ligature systems and the archwire types. Any significant friction differences between the steel-ligated, Slide
Interactive edgewise mechanisms: form and function comparison with conventional edgewise brackets.
Voudouris, J C
1997-02-01
As the frequency of use of the interactive twin (I-twin) edgewise mechanisms and techniques become increasingly prevalent, it is important to consider how they compare with conventional twin (c-twin) edgewise bracket systems. Optimum intrabracket and interbracket forces in I-twins balance with capillary blood pressures. An unbiased, experimental in vitro, scanning electromicroscopy and in vivo clinical investigation of 83 patients was conducted to compare the frictional resistance of three different I-twin bracket systems, type A (Sigma, American Orthodontics), type B (Interactwin, Ormco Corp.), and type C (Damon, A-company) with three c-twins counterparts respectively types D, E, and F. The three interactive twin brackets were each self-seating by an integrated arm component and made significant incremental improvements to the conventional twins in three different ways. First, the I-twin types reduced frictional resistance by using arm engagement with a lower coefficient of friction and a reduced seating force against the arch wire. The reduced seating force friction produced initially small interbracket arch wire deflections for biocompatible tooth movement and, combined with a wide twin bracket, produced accurate rotation corrections. Reduced friction within the I-twin bracket consequently permitted the effective use of light forces for flowing biomechanics that maximized anchorage. In evaluating friction, two distinctly different interaction forces acting to seat the arch wire were also identified. Type A demonstrated active interaction with round arch wires that resulted in a low functional seating force responsible for early and complete tooth control in comparison to the high seating force of c-twins. Types B and C both showed passive interaction with seating force friction approximately equal to zero that required large rectangular dimension arch wires for full bracket expression. Second, a significant reduction in the time taken to change arch wires was
Probability and radical behaviorism
Espinosa, James M.
1992-01-01
The concept of probability appears to be very important in the radical behaviorism of Skinner. Yet, it seems that this probability has not been accurately defined and is still ambiguous. I give a strict, relative frequency interpretation of probability and its applicability to the data from the science of behavior as supplied by cumulative records. Two examples of stochastic processes are given that may model the data from cumulative records that result under conditions of continuous reinforcement and extinction, respectively. PMID:22478114
Probability of satellite collision
NASA Technical Reports Server (NTRS)
Mccarter, J. W.
1972-01-01
A method is presented for computing the probability of a collision between a particular artificial earth satellite and any one of the total population of earth satellites. The collision hazard incurred by the proposed modular Space Station is assessed using the technique presented. The results of a parametric study to determine what type of satellite orbits produce the greatest contribution to the total collision probability are presented. Collision probability for the Space Station is given as a function of Space Station altitude and inclination. Collision probability was also parameterized over miss distance and mission duration.
NASA Astrophysics Data System (ADS)
Laktineh, Imad
2010-04-01
This ourse constitutes a brief introduction to probability applications in high energy physis. First the mathematical tools related to the diferent probability conepts are introduced. The probability distributions which are commonly used in high energy physics and their characteristics are then shown and commented. The central limit theorem and its consequences are analysed. Finally some numerical methods used to produce diferent kinds of probability distribution are presented. The full article (17 p.) corresponding to this lecture is written in french and is provided in the proceedings of the book SOS 2008.
STATISTICAL ANALYSIS, REPORTS), (*PROBABILITY, REPORTS), INFORMATION THEORY, DIFFERENTIAL EQUATIONS, STATISTICAL PROCESSES, STOCHASTIC PROCESSES, MULTIVARIATE ANALYSIS, DISTRIBUTION THEORY , DECISION THEORY, MEASURE THEORY, OPTIMIZATION
Brauchli, Lorenz; Steineck, Markus; Ball, Judith
2013-02-01
To evaluate the suitability of a novel epoxy-based resin, Filtek Silorane, for orthodontic bracket bonding on unprepared enamel. Shear forces to bovine enamel were measured for Filtek Silorane and Transbond XT in combination with steel, ceramic, and polymer brackets. For Filtek Silorane, etching was performed with the Silorane self-etching primer alone or an additional previous application of phosphoric acid. Transbond XT (conventional methacrylate) was used for the control group and the enamel was previously etched with 35% phosphoric acid. All samples were thermocycled (1000X, 5°to 55° C). Shear bond testing was done with an Instron 3344 at a crosshead speed of 1 mm/min. In addition, adhesive remnant index (ARI) scores were evaluated. The shear forces showed a weak adhesion of Filtek Silorane to unprepared enamel both with the selfetching primer and conventional etching (0.87 to 4.28 MPa). The shear forces of the control group were significantly higher (7.6 to 16.5 MPa). The ARI scores showed a clear failure at the enamel/adhesive interface for all Filtek Silorane samples. For the combination of Transbond XT and different brackets, the failure was found at the adhesive/bracket interface. The novel epoxy-based resin Filtek Silorane is not appropriate for bonding of brackets to unprepared enamel.
Debonding forces of three different customized bases of a lingual bracket system
Sung, Jang-Won; Kwon, Tae-Yub
2013-01-01
Objective The purpose of this study was to investigate whether extension of the custom base is necessary for enhancement of bond strength, by comparing the debonding forces and residual adhesives of 3 different lingual bracket systems. Methods A total of 42 extracted upper premolars were randomly divided into 3 groups of 14 each for bonding with brackets having (1) a conventional limited resin custom base; (2) an extended gold alloy custom base: Incognito™; and (3) an extended resin custom base: KommonBase™. The bonding area was measured by scanning the bracket bases with a 3-dimensional digital scanner. The debonding force was measured with an Instron universal testing machine, which applied an occlusogingival shear force. Results The mean debonding forces were 60.83 N (standard deviation [SD] 10.12), 69.29 N (SD 9.59), and 104.35 N (SD17.84) for the limited resin custom base, extended gold alloy custom base, and extended resin custom base, respectively. The debonding force observed with the extended resin custom base was significantly different from that observed with the other bases. In addition, the adhesive remnant index was significantly higher with the extended gold alloy custom base. Conclusions All 3 custom-base lingual brackets can withstand occlusal and orthodontic forces. We conclude that effective bonding of lingual brackets can be obtained without extension of the custom base. PMID:24228238
Orthodontic Metallic Lingual Brackets: The Dark Side of the Moon of Bond Failures?
Sfondrini, Maria Francesca; Gandini, Paola; Gioiella, Andrea; Zhou, Feng Xiao; Scribante, Andrea
2017-07-07
Lingual orthodontics, among both young and adult patients, increased in popularity during last years. The purposes of the present investigation were to evaluate the shear bond strength (SBS) values and Adhesive Remnant Index (ARI) scores of different lingual brackets compared with a vestibular control bracket. One hundred bovine teeth were extracted and embedded in resin blocks. Four different lingual brackets (Idea, Leone; STB, Ormco; TTR, RMO; 2D, Forestadent) and a vestibular control bracket (Victory, 3M) were bonded to the bovine enamel surfaces and subsequently shear tested to failure utilizing a Universal Testing Machine. SBS values were measured. A microscopic evaluation was performed to obtain ARI scores. Statistical analysis was performed at a statistically significant level of p < 0.05 to determine significant differences in SBS values and ARI Scores. No statistically significant variations in SBS were reported among the different groups. Conversely, significant differences were shown in ARI scores among the various groups. Clinical relevance of the present study is that orthodontists can expect similar resistance to debonding forces from lingual appliances as with vestibular brackets.
Jurišić, Sanja; Jurišić, Gordan
2015-01-01
Aim The objective of present study was to examine influence of adhesives and methods of enamel pretreatment on the shear bond strength (SBS) of orthodontic brackets. The adhesives used were resin-reinforced glass ionomer cements-GIC (Fuji Ortho LC) and composite resin (Transbond XT). Material and Methods The experimental sample consisted of 80 extracted human first premolars. The sample was divided into four equal groups, and the metal brackets were bonded with different enamel pretreatments by using two adhesives: group A-10% polyacrylic acid; Fuji Ortho LC, group B–37% phosphoric acid; Fuji Ortho LC, group C–self etching primer; Transbond XT, group D–37% phosphoric acid, primer; Transbond XT. SBS of brackets was measured. After debonding of brackets, the adhesive remnant index (ARI) was evaluated. Results After the statistical analysis of the collected data was performed (ANOVA; Sheffe post-hoc test), the results showed that significantly lower SBS of the group B was found in relation to the groups C (p=0.031) and D (p=0.026). The results of ARI were similar in all testing groups and it was not possible to determine any statistically significant difference of the ARI (Chi- square test) between all four experimental groups. Conclusion The conclusion is that the use of composite resins material with appropriate enamel pretreatment according to manufacturer’s recommendation is the “gold standard” for brackets bonding for fixed orthodontic appliances. PMID:27688410
In vitro analysis of shear bond strength and adhesive remnant index of different metal brackets
Henkin, Fernanda de Souza; de Macêdo, Érika de Oliveira Dias; Santos, Karoline da Silva; Schwarzbach, Marília; Samuel, Susana Maria Werner; Mundstock, Karina Santos
2016-01-01
ABSTRACT Introduction: There is a great variety of orthodontic brackets in the Brazilian market, and constantly evaluating them is critical for professionals to know their properties, so as to be able to choose which product best suits their clinical practice. Objectives: To evaluate the bond strength and the adhesive remnant index (ARI) of different brands of metal brackets. Material and Methods: A total of 105 bovine incisors were used, and brackets of different brands were bonded to teeth. Seven different bracket brands were tested (MorelliTM, American OrthodonticsTM, TP OrthodonticsTM, Abzil-3MTM, OrthometricTM, TecnidentTM and UNIDENTM). Twenty-four hours after bonding, shear bond strength test was performed; and after debonding, the ARI was determined by using an optical microscope at a 10-fold increase. Results: Mean shear bond strength values ranged from 3.845 ± 3.997 (MorelliTM) to 9.871 ± 5.106 MPa (TecnidentTM). The majority of the ARI index scores was 0 and 1. Conclusion: Among the evaluated brackets, the one with the lowest mean shear bond strength values was MorelliTM. General evaluation of groups indicated that a greater number of bond failure occurred at the enamel/adhesive interface. PMID:28125142
Influence of surface treatments on the shear bond strength of orthodontic brackets to porcelain
NASA Astrophysics Data System (ADS)
Wang, Cong; Zeng, Jishan; Wang, Shaoan; Yang, Zheng; Huang, Qian; Chen, Pixiu; Zhou, Shujuan; Liu, Xiaoqing
2008-11-01
The purpose of this study was to investigate the effect of various surface treatments after different storage time and thermocycling on the shear bond strength of orthodontic brackets to the feldspathic porcelain surfaces. 128 disc-shaped porcelain specimens were randomly assigned to the following surface treatments: 9.6% HFA, 9.6% HFA combined with silane, 50 μ aluminum trioxide sandblasting followed by silane and application of silane after 37% phosphoric acid. Metal or ceramic brackets were bonded onto each treated porcelain facet with light cured resin. The samples were stored in 37 °C water 1 day or 7 days, thermocycled 500 times from 5 to 55 °C. The shear bond strengths were measured (1 mm/min), and statistically analyzed. The bond failure sites were classified according to ARI system. The surface of the glazed, sandblasted, hydrofluoric and phosphoric acid etched porcelain were examined with SEM. All groups achieved reasonable bond strengths to withstand the application of orthodontic forces. Water storage for 7 days caused lower shear bond strength than that of 1 day. But there is no statistically significant difference between the two groups. The mean shear bond strength provided by ceramic bracket with mechanical retention had no statistical difference with that of metal bracket. Therefore, the optimal treatment for orthodontic brackets bonding to feldspathic porcelain was to apply phosphoric acid combined with silane.
The effect of enamel bleaching on the shear bond strengths of metal and ceramic brackets.
Oztaş, E; Bağdelen, G; Kiliçoğlu, H; Ulukapi, H; Aydin, I
2012-04-01
The aim of this study was to evaluate the effects of bleaching and delayed bonding on the shear bond strengths of metal and ceramic brackets bonded with light and chemically cure composite resin to human enamel. One hundred and twenty extracted human premolar teeth were randomly divided into three groups of 40 each. The first two groups were bleached with 20 per cent carbamide peroxide (CP) at-home bleaching agent. No bleaching procedures were applied to the third group and served as control. The first two and control groups were divided into equal subgroups according to different adhesive-bracket combinations. Specimens in group 1 (n = 40) were bonded 24 hours after bleaching process was completed while the specimens in group 2 (n = 40) were bonded 14 days after. The specimens in all groups were debonded with a Universal testing machine while the modified adhesive remnant index was used to evaluate fracture properties. No statistically significant differences were found between the shear bond strengths of metal and ceramic brackets bonded to bleached enamel after 24 hours, 14 days, and unbleached enamel with light or chemical cure adhesives (P > 0.05). The mode of failure was mostly at the bracket/adhesive interface and cohesive failures within the resin were also observed. Our findings indicated that at-home bleaching agents that contain 20 per cent CP did not significantly affect the shear bond strength of metal and ceramic orthodontic brackets to enamel when bonding is performed 24 hours or 14 days after bleaching.
Bracket angulation as a function of its length in the canine distal movement.
Matasa, C G
1996-08-01
The slot angulations that are built into currently manufactured brackets are the same as those recommended more than 20 years ago. Because of a continuous trend toward miniaturization, the bracket slot length has diminished considerably, fact that should have had an impact on the characteristics of the slot. This impact has not yet taken place. A decrease in the overall bracket size and the shortening of the slot length invite unaccounted tooth rotation, which happens when an attempt is made to adhere to traditional angulations. If only a pure translation of a tooth is wanted, such a rotation becomes undesirable. To reduce its action, power arms are used. Unfortunately, these do not solve the problem. Indeed, to overcome this effect, a modification of the values of standard angulations is needed. To illustrate the point, maxillary canine retraction is considered, because it is both common and involves an already high bracket slot angulation. With standard solid mechanics and statics, new angulations are proposed as functions of the bracket slot length and arch wire rigidity. In addition, an estimation of the minimum useful size of the slot is made.
Bleaching and desensitizer application effects on shear bond strengths of orthodontic brackets.
Türkkahraman, Hakan; Adanir, Necdet; Güngör, A Yalcin
2007-05-01
To evaluate the effects of bleaching and desensitizer application on shear bond strengths of orthodontic brackets. Forty-eight extracted human premolar teeth were randomly assigned to 4 groups of 12 each. The first group of teeth was bleached with a 35% hydrogen peroxide office bleaching agent. The second group was bleached the same as the first group and UltraEZ desensitizer was applied. No bleaching procedures were applied on the third and fourth groups. UltraEZ desensitizer alone was applied to teeth in the third group. The fourth group served as control. Orthodontic brackets were bonded with a LC (light cure) composite resin and cured with a halogen light. After bonding, the shear bond strengths of the brackets were tested with a Universal testing machine. The results showed that bleaching, bleaching plus desensitizer, and desensitizer procedures significantly reduced the bonding strengths of the orthodontic brackets (P < .05, P < .001, and P < .01, respectively). No statistically significant difference was found between bleaching, bleaching plus desensitizer, and desensitizer groups (P > .05). Because bleaching and desensitizer application significantly affected shear bond strengths of orthodontic brackets on human enamel, they should be delayed until the completion of orthodontic treatment.
A Comparison of Gender and Socioeconomic Bracket in Fourth Grade Students when Measuring Volume
NASA Astrophysics Data System (ADS)
Jennings, Kelly A.
The goal of this study was to assess students' abilities when measuring volume as well as providing a hands-on method for designing a water-filtration process. I studied the trends among gender, time, and ability to measure water in two different groups of fourth grade students. Fourth grade students from both higher income and lower income school districts visited a STEM (Science, Technology, Engineering, and Mathematics) Studio in order to participate in hands-on, problem-based learning. The students in this study attempted to solve the "Dirty Water Problem" by measuring 281ml of dirty water solution, and using household tools to filter and clean the dirty water. This study showed that 68% of students from a high-income socioeconomic bracket were able to measure a determined volume of water independently. Meanwhile, only 18% of students from a low-income socioeconomic bracket were able to complete the same task independently. In the low-income bracket, 78% of students required assistance measuring a volume of water, indicating that the majority of these students performed below grade level. Where time spent at the station was concerned, the difference between high-income and low-income socioeconomic brackets was insignificant. Key Words: STEM, measurement, volume, design, Dirty Water Problem, socioeconomic bracket.
A method for producing controlled fluoride release from an orthodontic bracket.
Li, Song; Hobson, Ross S; Bai, Yuxing; Yan, Zhuoqun; Carrick, Thomas E; McCabe, John F
2007-12-01
The aim of this study was to manufacture and test, in vitro, a novel modification to provide fluoride-releasing orthodontic brackets. Thirty-two orthodontic brackets were drilled to produce a recess (approximately 1.3 mm in diameter and 0.7 mm in depth) at the centre of the bracket base. Four materials, with and without the addition of sodium fluoride, a glass ionomer cement (Ketac Cem micro), a resin-modified glass ionomer cement (RMGIC; GC Fuji Ortho LC), a zinc phosphate (Zinc Cement Improved), and a resin (Transbond XT) were used to fill the recess in the bracket base. Fluoride release was measured daily during the first week and then weekly for 10 weeks. An ion chromatograph with suppressed conductivity was used for free fluoride ion determination. Statistical analysis to determine the amount of flouride release was undertaken using analysis of variance and Tukey's test. During the first 2 weeks, the resin group, with the addition of 38 per cent sodium fluoride added, released significantly more free fluoride (P < 0.05), but after 2 weeks the fluoride release markedly decreased. After 5 weeks, the RMGIC group, with 15 per cent added sodium fluoride, had significantly higher (P < 0.05) daily fluoride release than the other groups. The findings demonstrated that an appropriate fluoridated material can be used as a fluoride-releasing reservoir in a modified orthodontic bracket to enable it to release fluoride over the period of fixed appliance treatment.
Lugato, Isabel Cristina Prado Torres; Pignatta, Lilian Maria Brisque; Arantes, Flávia de Moraes; Santos, Eduardo César Almada
2009-01-01
This study aimed to compare in vitro the shear bond strength between metallic brackets (Abzil) with conventional mesh bases and metallic brackets with bases industrially sandblasted with aluminum oxide using three adhesive systems, in order to assess the influence of sandblasting on adhesiveness and to compare 3 different bonding systems. Two hundred and forty bovine incisors were used and randomly divided into 6 groups (40 teeth in each group), according to the bracket base and to the bonding system. The brackets were direct-bonded in bovine teeth with 3 adhesive systems: System A - conventional Transbond XT (3M - Unitek); System B - Transbond Plus Self Etching Primer + Transbond XT (3M - Unitek) and System C - Fuji ORTHO LC resin-reinforced glass ionomer cement in capsules (GC Corp.). Shear bond strength tests were performed 24 hours after bonding, in a DL-3000 universal testing machine (EMIC), using a load cell of 200 kgf and a speed of 1 mm/min. The results were submitted to statistical analysis and showed no significant difference between conventional and sandblasted bracket bases. However, comparison between the bonding systems presented significantly different results. System A (14.92 MPa) and system C (13.24 MPa) presented statistically greater shear bond strength when compared to system B (10.66 MPa). There was no statistically significant difference between system A and system C.
Türkkahraman, Hakan; Adanir, Necdet
2007-11-01
To evaluate the effects of potassium nitrate and oxalate desensitizer agents on shear bond strengths of orthodontic brackets. Forty-five extracted human premolar teeth were randomly assigned to three groups of 15 each. UltraEZ potassium nitrate desensitizer was applied on teeth in the first group, while BisBlock oxalate desensitizer was applied on teeth in the second group. The third group served as a control. Orthodontic brackets were bonded with a light cure composite resin and cured with a halogen light. After bonding, the shear bond strength of the brackets was tested with a universal testing machine. The highest shear bond strengths were measured in Group III. The shear bond strength in Groups I and II was significantly lower than in Group III (P < .001). Significant difference was also found between Group I and Group II (P < .01). Orthodontic brackets bonded to enamel treated with potassium nitrate and oxalate desensitizers showed significantly lower bond strengths than did brackets bonded to untreated enamel.
Pulpal thermal changes following Er-YAG laser debonding of ceramic brackets.
Nalbantgil, Didem; Tozlu, Murat; Oztoprak, Mehmet Oguz
2014-01-01
Lasers are effective in debonding ceramic brackets. Unfortunately, while reducing the adhesive bond strength, lasers are also reported to increase pulpal temperature. The aim of this study was to evaluate the shear bond strengths and temperature increase levels after debonding ceramic brackets using an Er-YAG laser with or without water-cooling. Sixty polycrystalline upper premolar ceramic brackets were placed on the labial surface of sixty human premolar teeth which were randomly divided into three groups of twenty. A laser pulse at 5 W for 9 seconds was delivered to each bracket in both study groups either with water-cooling (water group) or without water-cooling (waterless group) using an Er-YAG laser. Debonding was performed 45 seconds after laser exposure and shear bond strengths were measured. Data comparison revealed a statistically significant difference between the groups. Mean temperature increases of 2.41°C and 4.59°C were recorded for the water and waterless laser groups, respectively. The shear bond strength value for the control group was 22.76 MPa and 10.46 and 6.36 MPa for the water and waterless laser groups, respectively. The application of Er-YAG laser with water-cooling was an efficient and safe method of debonding ceramic brackets.
Lifting of the Vlasov-Maxwell Bracket by Lie-transform Method
NASA Astrophysics Data System (ADS)
Brizard, A. J.; Morrison, P. J.; Burby, J. W.
2016-10-01
The Vlasov-Maxwell equations possess a Hamiltonian structure expressed in terms of a Hamiltonian functional and a functional bracket. The transformation (``lift'') of the Vlasov-Maxwell bracket induced by the dynamical reduction of single-particle dynamics is investigated when the reduction is carried out by Lie-transform perturbation methods. The ultimate goal of this work is to derive explicit Hamiltonian formulations for the guiding-center and gyrokinetic Vlasov-Maxwell equations that have important applications in our understanding of turbulent magnetized plasmas. In particular, we investigate how the Hamiltonian properties of the reduced Vlasov-Maxwell bracket survive (1) the closure problem: the process of truncation of the guiding-center Vlasov-Maxwell bracket at a finite order in ɛ (so far expressions have been derived at all orders in ɛ) and (2) the averaging problem: the process by which which the gyroangle is eliminated from the guiding-center Vlasov-Maxwell bracket (since guiding-center Vlasov-Maxwell equations do not involve the fast gyromotion time scale). Work supported by Grants from US DoE.
Nayak, Rabindra S; Shafiuddin, Bareera; Pasha, Azam; Vinay, K; Narayan, Anjali; Shetty, Smitha V
2015-01-01
Background: Technological advances in wire selection and bracket design have led to improved treatment efficiency and allowed longer time intervals between appliance adjustments. The wires remain in the mouth for a longer duration and are subjected to electrochemical reactions, mechanical forces of mastication and generalized wear. These cause different types of corrosion. This study was done to compare the galvanic currents generated between different combinations of brackets and archwires commonly used in orthodontic practices. Materials and Methods: The materials used for the study included different commercially available orthodontic archwires and brackets. The galvanic current generated by individual materials and different combinations of these materials was tested and compared. The orthodontic archwires used were 0.019″ × 0.025″ heat-activated nickel-titanium (3M Unitek), 0.019″ × 0.025″ beta-titanium (3M Unitek) and 0.019″ × 0.025″ stainless steel (3M Unitek). The orthodontic brackets used were 0.022″ MBT laser-cut (Victory Series, 3M Unitek) and metal-injection molded (Leone Company) maxillary central incisor brackets respectively. The ligature wire used for ligation was 0.009″ stainless steel ligature (HP Company). The galvanic current for individual archwires, brackets, and the different bracket-archwire-ligature combinations was measured by using a Potentiostat machine. The data were generated using the Linear Sweep Voltammetry and OriginPro 8.5 Graphing and Data Analysis Softwares. The study was conducted in two phases. Phase I comprised of five groups for open circuit potential (OCP) and galvanic current (I), whereas Phase II comprised of six groups for galvanic current alone. Results: Mean, standard deviation and range were computed for the OCP and galvanic current (I) values obtained. Results were subjected to statistical analysis through ANOVA. In Phase I, higher mean OCP was recorded in stainless steel archwire, followed by beta
Nayak, Rabindra S; Shafiuddin, Bareera; Pasha, Azam; Vinay, K; Narayan, Anjali; Shetty, Smitha V
2015-07-01
Technological advances in wire selection and bracket design have led to improved treatment efficiency and allowed longer time intervals between appliance adjustments. The wires remain in the mouth for a longer duration and are subjected to electrochemical reactions, mechanical forces of mastication and generalized wear. These cause different types of corrosion. This study was done to compare the galvanic currents generated between different combinations of brackets and archwires commonly used in orthodontic practices. The materials used for the study included different commercially available orthodontic archwires and brackets. The galvanic current generated by individual materials and different combinations of these materials was tested and compared. The orthodontic archwires used were 0.019″ × 0.025″ heat-activated nickel-titanium (3M Unitek), 0.019″ × 0.025″ beta-titanium (3M Unitek) and 0.019″ × 0.025″ stainless steel (3M Unitek). The orthodontic brackets used were 0.022″ MBT laser-cut (Victory Series, 3M Unitek) and metal-injection molded (Leone Company) maxillary central incisor brackets respectively. The ligature wire used for ligation was 0.009″ stainless steel ligature (HP Company). The galvanic current for individual archwires, brackets, and the different bracket-archwire-ligature combinations was measured by using a Potentiostat machine. The data were generated using the Linear Sweep Voltammetry and OriginPro 8.5 Graphing and Data Analysis Softwares. The study was conducted in two phases. Phase I comprised of five groups for open circuit potential (OCP) and galvanic current (I), whereas Phase II comprised of six groups for galvanic current alone. Mean, standard deviation and range were computed for the OCP and galvanic current (I) values obtained. Results were subjected to statistical analysis through ANOVA. In Phase I, higher mean OCP was recorded in stainless steel archwire, followed by beta-titanium archwire, heat-activated nickel
Klang, Elisabeth; Helms, Hans-Joachim; Wiechmann, Dirk
2016-01-01
Summary Background: Using lingual enamel surfaces for bracket placement not only has esthetic advantages, but may also be suitable in terms of reducing frequencies of enamel decalcifications. Objective: To test the null-hypothesis that there is no significant difference in enamel decalcification or cavitation incidence adjacent to and beneath bracket bases between two lingual multi-bracket (MB) appliances that are different in terms of design, material composition, and manufacturing technology (group A: WIN, DW-LingualSystems; group B: Incognito, 3M-Unitek), taking into account patient- and treatment-related variables on white spot lesion (WSL) formation. Methods: Standardized, digital, top-view photographs of 630 consecutive subjects (16214 teeth; n Incognito = 237/6076 teeth; n WIN = 393/10138 teeth; mean age: 17.47±7.8; m/f 43.2/56.8%) with completed lingual MB treatment of the upper and lower permanent teeth 1–7 were screened for decalcification or cavitation adjacent to and beneath the bracket bases before and after treatment, scored from 0 to 7. Non-parametric ANOVA was used for main effects ‘appliance type’, ‘gender’, ‘treatment complexity’, ‘grouped age’ (≤16/>16 years), and ‘treatment duration’ as covariable, at an α-level of 5%. Results: About 2.57% [5.94%] of all teeth in group A [B] developed decalcifications. Subject-related incidence was 9.59% [16.17%] for upper incisors in group A [B], and 12.98% [25.74%] for all teeth 16–46. There were significant effects by gender, age, and treatment duration. Conclusion: The null-hypothesis was rejected: sub-bracket lesions were significantly less frequent in group A, while frequencies of WSL adjacent to brackets were not significantly affected by appliance type. In view of the overall low incidences of lingual post-orthodontic white-spot lesions, the use of lingual appliances is advocated as a valid strategy for a reduction of enamel decalcifications during orthodontic treatment. PMID
Behroozian, Ahmad; Kachoei, Mojgan; Khatamian, Masumeh; Divband, Baharak
2016-01-01
Background. Any decrease in friction between orthodontic wire and bracket can accelerate tooth movement in the sliding technique and result in better control of anchorage. This study was carried out to evaluate frictional forces by coating orthodontic wires and porcelain brackets with zinc oxide nanoparticles (ZnO). Methods. In this in vitro study, we evaluated a combination of 120 samples of 0.019×0.025 stainless steel (SS) orthodonticwires and 22 mil system edgewise porcelain brackets with and without spherical zinc oxide nanoparticles. Spherical ZnOnanoparticles were deposited on wires and brackets by immersing them in ethanol solution and SEM (scanning electronmicroscope) evaluation confirmed the presence of the ZnO coating. The frictional forces were calculated between the wiresand brackets in four groups: group ZZ (coated wire and bracket), group OO (uncoated wire and bracket), group ZO (coatedwire and uncoated bracket) and group OZ (uncoated wire and coated bracket). Kolmogorov-Smirnov, Mann-Whitney andKruskal-Wallis tests were used for data analysis. Results. The frictional force in ZZ (3.07±0.4 N) was the highest (P <0.05), and OZ (2.18±0.5 N) had the lowest amount of friction (P <0.05) among the groups. There was no significant difference in frictional forces between the ZO and OO groups (2.65±0.2 and 2.70±0.2 N, respectively). Conclusion. Coating of porcelain bracket surfaces with ZnO nanoparticles can decrease friction in the sliding technique,and wire coating combined with bracket coating is not recommended due to its effect on friction. PMID:27429727
Henao, Sandra P; Kusy, Robert P
2004-04-01
The frictional behavior of four conventional and four self-ligating brackets were simulated using a mechanical testing machine. Analyses of the two-bracket types were completed by drawing samples of three standardized archwires through quadrants of typodont models in the dry/wet states. Pretreatment typodonts of an oral cavity featured progressively malocclused quadrants. As nominal dimensions of the archwires were increased, the drawing forces of all brackets increased at different rates. When coupled with a small wire, the self-ligating brackets performed better than the conventional brackets. For the 0.014-inch wires in the upper right quadrant, the maximum drawing forces averaged 125 and 810 cN for self-ligating and conventional brackets, respectively. When coupled with larger wires, various designs interchangeably displayed superior performance. For the 0.019- x 0.025-inch wires in the upper left quadrant, the maximum drawing forces averaged 1635 and 2080 cN for self-ligating and conventional brackets, respectively. As the malocclusion increased, the drawing forces increased. For example, in the least malocclused quadrant and with the smallest wire, maximum drawing forces for self-ligating and conventional brackets averaged 80 and 810 cN, respectively, whereas in the most malocclused quadrant tested with the same wire size, maximum drawing forces for self-ligating and conventional brackets averaged 870 and 1345 cN, respectively. For maximum values between the dry and wet states, significant differences between ambient states existed only for the In-Ovation brackets in the lower left quadrant. These test outcomes illustrated how bracket design, wire size, malocclusion, and ambient state influenced drawing forces.
ERIC Educational Resources Information Center
Barnes, Bernis, Ed.; And Others
This teacher's guide to probability and statistics contains three major sections. The first section on elementary combinatorial principles includes activities, student problems, and suggested teaching procedures for the multiplication principle, permutations, and combinations. Section two develops an intuitive approach to probability through…
Teachers' Understandings of Probability
ERIC Educational Resources Information Center
Liu, Yan; Thompson, Patrick
2007-01-01
Probability is an important idea with a remarkably wide range of applications. However, psychological and instructional studies conducted in the last two decades have consistently documented poor understanding of probability among different populations across different settings. The purpose of this study is to develop a theoretical framework for…
Complexity VIII. Ontology of closure in complex systems: The C* hypothesis and the O° notation
NASA Astrophysics Data System (ADS)
Chandler, Jerry LR
1999-03-01
Closure is a common characteristic of mathematical, natural and socio-cultural systems. Whether one is describing a graph, a molecule, a cell, a human, or a nation state, closure is implicitly understood. An objective of this paper is to continue a construction of a systematic framework for closure which is sufficient for future quantitative transdisciplinary investigations. A further objective is to extend the Birkhoff-von Neumann criterion for quantum systems to complex natural objects. The C* hypothesis is being constructed to be consistent with algebraic category theory (Ehresmann and Vanbremeersch, 1987, 1997, Chandler, 1990, 1991, Chandler, Ehresmann and Vanbremeersch, 1996). Five aspects of closure will be used to construct a framework for categories of complex systems: 1. Truth functions in mathematics and the natural sciences 2. Systematic descriptions in the mks and O° notations 3. Organizational structures in hierarchical scientific languages 4. Transitive organizational pathways in the causal structures of complex behaviors 5. Composing additive, multiplicative and exponential operations in complex systems Truth functions can be formal or objective or subjective, depending on the complexity of the system and on our capability to represent the fine structure of the system symbolically, observationally or descriptively. "Complete" material representations of the fine structure of a system may allow truth functions to be created over sets of one to one correspondences. Less complete descriptions can support less stringent truth functions based on coherence or subjective judgments. The role of human values in creating and perpetuating truth functions can be placed in context of the degree of fine structure in the system's description. The organization of complex systems are hypothesized to be categorizable into degrees relative to one another, thereby creating an ordering relationship. This ordering relationship is denoted by the symbols: O°1, O°2,O°3
Behroozi, Zeinab; Momeni Danaei, Shahla; Sardarian, Ali Reza; Moshkelghosha, Vahid; Sardarian, Ahmad Reza
2016-01-01
Statement of the Problem: Stainless steel brackets release metallic ions following the process of corrosion in the oral environment. These released ions have potential adverse effects on health, friction between wire and bracket, staining, strength of brackets. Choosing a bracket with favorable corrosive properties; therefore, should be a goal of every practitioner. Purpose: The goal of this study is to compare the amount of corrosion among five different brands of brackets using inductively coupled plasma (ICP) mass spectrometry. Materials and Method: Five different brands of brackets (Dentaurum, 3M, Ortho Organizer, Cobas and O.R.G) were chosen and ten brackets were selected from each brand. A piece of stainless steel wire was ligated to each bracket. The bracket-archwire complex was then immersed in artificial saliva. Subsequently, the samples were analyzed using an ICP device and the levels of iron, chromium, nickel, and manganese ions were measured. Results: The findings of this study demonstrated that iron was released the most from the tested brackets, followed by nickel. We also found that the Cobas bracket had the most ion release among the tested brackets (p< 0.05), while Ortho Organizer and ORG performed favorably. There was no significant difference between Dentaurum and 3M (p> 0.05). Conclusion: Based on the results, Ortho Organizer and ORG brackets are suggested in terms of resistance to corrosion. PMID:27840839
[In-vitro research on the thermal debonding of ceramic brackets].
Bäzner, B; Ettwein, K H; Röhlcke, F; Sernetz, F
1991-12-01
The mechanical debonding of ceramic brackets using special instruments involves the use of a degree of force that is damaging to the enamel. For this reason, the authors have developed the Ceramic Debonding Unit for the thermal debonding of ceramic brackets. The unit reduces the force necessary for debonding, without overheating the tooth. The present article explains the principle of the unit. The influence on the temperature increase in the pulpa of the mechanical torque applied during debonding, and the time taken for debonding was investigated in extracted teeth (lower central incisors). Tests on ceramic brackets made by various manufacturers showed that safe debonding is possible if the debonding time does not exceed 3 seconds at a torque of 100 Nnm. The temperature increase in the pulpa will not exceed 5 degrees C when the Ceramic Debonding Unit is used under these conditions, so that harmful overheating of healthy teeth does not occur.
Adanir, Necdet; Türkkahraman, Hakan; Yalçin Güngör, Ahmet
2009-06-01
The aims of this in vitro study were to evaluate the effect of enamel fluorosis on the shear bond strength (SBS) of orthodontic brackets and to determine whether adhesion promoter, Enhance LC, increases the bond strength of brackets to fluorosed enamel. Forty-five (30 fluorosed and 15 non-fluorosed) non-carious fresh human premolar teeth, extracted for orthodontic reasons and without any caries or visible defects, were used in this study. The fluorosed teeth were selected according to the modified Thylstrup and Fejerskov index, which is based on the clinical changes in fluorosed teeth. In groups 1 (fluorosed teeth) and 3 (control), the brackets were bonded with Light Bond composite resin and cured with a halogen light. In group 2, Enhance LC was applied to fluorosed enamel before bonding. After bonding, the SBS of the brackets was tested with a universal testing machine. One-way analysis of variance and Tukey multiple comparison tests were used to compare the SBS of the groups. Any adhesive remaining after debonding was assessed and scored according to the modified adhesive remnant index. The results showed that while fluorosis significantly reduced the bond strengths of the orthodontic brackets (mean 13.94 +/- 3.24 MPa; P < 0.01), Enhance LC significantly increased bond strength on fluorosed enamel (mean 18.22 +/- 5.97 Mpa; P < 0.05). Groups 1 and 3 had greater bond failures at the composite-bracket interface, whereas group 2 showed bond failure primarily at the enamel-composite interface.
NASA Astrophysics Data System (ADS)
Gilbert, Danielle Wiggins
This study examined the effect of varying delayed polymerization times in combination with bracket manipulation on shear bond strength (SBS), degree of conversion (DC), and adhesive remnant index (ARI) score when using a resin modified glass ionomer (RMGI) adhesive. Specimens were divided into three groups of clinically relevant delay times (0.5, 2, and 4-min) to simulate the delay that frequently occurs between bracket placement and manipulation and subsequent light curing. Based on an analysis of variance (alpha=.05), the SBS was not significantly different between the three groups. While one of the goals of this study was to be the first study to quantify DC of RMGI using Raman microspectroscopy, several challenges, including weak peak signal with and without fluorescence, were encountered and as a result, DC could not be determined. A significant difference (p<0.05) in ARI score was detected between the 0.5-min and 4.0-min delay groups with more adhesive remaining on the bracket with increasing delay time. A Spearman correlation between SBS and ARI indicated no positive association between SBS and ARI measures across delay times. The results of this study suggest that clinically relevant delay times of 0.5, 2, and 4-min do not negatively impact the SBS of a RMGI adhesive. However, with increasing delay time, the results suggest that more adhesive might remain on the bracket during debonding. With more adhesive remaining on the bracket, this could be beneficial in that less adhesive needs to be removed from enamel by grinding at the time of bracket removal when orthodontic treatment is completed.