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1

Partial molar volumes of amino acid derivatives in water  

Microsoft Academic Search

The partial molar volumes at infinite dilution for a number of hydrochlorides and sodium salts of N-methyl derivatives of a, ?-aminocarboxylic acids in water at 25°C are measured and related to their van der Waals volumes. Results indicate that 4.96±0.48 water molecules hydrate a betaine hydrochloride. Volumes of proton ionization and interaction terms are evaluated. Group contributions to the partial

Fereidoon Shahidi

1983-01-01

2

Partial molar volume reduction of solvent for solute crystallization using carbon dioxide as antisolvent  

Microsoft Academic Search

The gas antisolvent crystallization (GASC) process using dense carbon dioxide (CO2) as antisolvent is particularly useful for purification and micronization of thermo-labile bioactive solid substances. Conventionally, the GASC process is characterized by the relative total volume expansion or the relative molar volume expansion of the solution. A new criterion is proposed in this work in terms of the relative partial

Mamata Mukhopadhyay

2003-01-01

3

Compositional dependent partial molar volume and compressibility of CO2 in rhyolite, phonolite and basalt glasses  

NASA Astrophysics Data System (ADS)

Carbon dioxide is the second most abundant volatile in magmatic systems and plays an important role in many magmatic processes, e.g. partial melting, volatile saturation, outgassing. Despite this relevance, the volumetric properties of carbon-bearing silicates at relevant pressure and temperature conditions remain largely unknown because of considerable experimental difficulties associated with in situ measurements. Density and elasticity measurements on quenched glasses can provide an alternative source of information. For dissolved water, such measurements indicate that the partial molar volume is independent of compositions at ambient pressure [1], but the partial molar compressibility is not [2, 3]. Thus the partial molar volume of water may depend on melt composition at elevated pressure. For dissolved CO2, no such data is available. In order to constrain the effect of magma composition on the partial molar volume and compressibility of dissolved carbon, we determined the density and elasticity for three series of carbon-bearing basalt, phonolite and rhyolite glasses, quenched from 3.5 GPa and relaxed at ambient pressure. The CO2 content varies between 0 to 3.90 wt% depending on the glass composition. Glass densities were determined using the sink/float method in a diiodomethane (CH2I2) - acetone mixture. Brillouin measurements were conducted on relaxed and unrelaxed silicate glasses in platelet geometry to determine the compressional (VP) and shear (VS) wave velocities and elastic moduli. The partial molar volume of CO2 in rhyolite, phonolite and basalt glasses is 25.4 ± 0.9, 22.1 ± 0.6 and 26.6 ±1.8 cm3/mol, respectively. Thus, unlike for dissolved water, the partial molar volume of CO2 displays a resolvable compositional effect. Although the composition and CO2/carbonate speciation of the phonolite glasses is intermediate between that of the rhyolite and basalt glasses, the molar volume is not. Similar to dissolved water, the partial molar bulk modulus of CO2 displays a strong compositional effect. If these compositional dependencies persist in the analogue melts, the partial molar volume of dissolved CO2 will depend on melt composition, both at low and elevated pressure. Thus, for CO2-bearing melts, a full quantitative understanding of density dependent magmatic processes, such as crystal fractionation, magma mixing and melt extraction will require in situ measurements for a range of melt compositions. [1] Richet, P. et al., 2000, Contrib Mineral Petrol, 138, 337-347. [2] Malfait et al. 2011, Am. Mineral. 96, 1402-1409. [3] Whittington et al., 2012, Am. Mineral. 97, 455-467.

Lerch, P.; Seifert, R.; Malfait, W. J.; Sanchez-Valle, C.

2012-12-01

4

On the magnitude of border thickness in the partial molar volume of cavities in water  

NASA Astrophysics Data System (ADS)

Analysis of the partial molar volumes of large Lennard-Jones solutes in the TIP3P water model has shown that the border thickness is markedly larger than 0.5 Å [Biophys. Chem. 161 (2012) 46]. I confirm this result by analyzing the cavity partial molar volumes obtained by means of Monte Carlo simulations in the TIP4P water model [J. Phys. Chem. B 108 (2004) 16244]. It is argued that, very likely, these results are a consequence of some limitations/deficiencies of the water models used in computer simulations.

Graziano, Giuseppe

2013-05-01

5

Pseudo-critical behavior on the partial molar volume of solutes in the isotropic phase of liquid crystal  

NASA Astrophysics Data System (ADS)

Temperature dependence of partial molar volume of 4-amino-4?-nitrobiphenyl (ANB) and 4,4?-dinitrobiphenyl (DNB) in the isotropic phase of 4-n-pentyl-4?-cyanobiphenyl (5CB) was determined. Addition of ANB to 5CB causes increase of isotropic-nematic phase transition temperature (TIN) [1]. The decrease of partial molar volume of ANB was observed while the increase of partial molar volume of DNB and triphenyl phosphite (TPP) [8] was observed with approaching TIN. The anomalous behavior of partial molar volume was discussed using treatments similar to that of other thermodynamic derivatives in the I-N transition.

Matsuoka, Tatsuro; Nakamura, Shunsuke; Yamaguchi, Tsuyoshi; Koda, Shinobu

2012-01-01

6

On a relationship between molecular polarizability and partial molar volume in water  

NASA Astrophysics Data System (ADS)

We reveal a universal relationship between molecular polarizability (a single-molecule property) and partial molar volume in water that is an ensemble property characterizing solute-solvent systems. Since both of these quantities are of the key importance to describe solvation behavior of dissolved molecular species in aqueous solutions, the obtained relationship should have a high impact in chemistry, pharmaceutical, and life sciences as well as in environments. We demonstrated that the obtained relationship between the partial molar volume in water and the molecular polarizability has in general a non-homogeneous character. We performed a detailed analysis of this relationship on a set of ~200 organic molecules from various chemical classes and revealed its fine well-organized structure. We found that this structure strongly depends on the chemical nature of the solutes and can be rationalized in terms of specific solute-solvent interactions. Efficiency and universality of the proposed approach was demonstrated on an external test set containing several dozens of polyfunctional and druglike molecules.

Ratkova, Ekaterina L.; Fedorov, Maxim V.

2011-12-01

7

Partial molar volumes, expansibilities and compressibilities of glyglyglycine in aqueous sucrose and fructose solutions between 288.15 and 308.15 K  

Microsoft Academic Search

Apparent molar volumes (V?) and apparent molar adiabatic compressibilities (K?,s) of triglycine (glyglyglycine) in aqueous and mixed aqueous solutions of fructose and sucrose (2, 4, and 6mass%) have been determined at 288.15, 293.15, 298.15, 303.15, and 308.15K. From these data, limiting partial molar volumes (V?0) and limiting partial molar adiabatic compressibilities (K?,s0) for glyglyglycine in aqueous sucrose and fructose solutions

Amalendu Pal; Nalin Chauhan

2011-01-01

8

Excess partial molar volumes and thermal expansivities in the water-rich region of aqueous 2-butanone  

Microsoft Academic Search

Excess partial molar volumes of 2-butanone VmE(B) and thermal expansivities ap were measured in the water-rich region of aqueous 2-butanone. The composition derivatives of both quantities showed anomalies at about XB=0.033 (xB is the mole fraction of B).\\u000a$$(\\\\partial V_m^E (B)\\/\\\\partial n_B )_{p,T,n_w }$$\\u000a showed a step anomaly, while\\u000a$$(\\\\partial \\\\alpha _p \\/\\\\partial n_B )_{p,T,n_w }$$\\u000a exhibited a peak anomaly.

James V. Davies; Robert Fooks; Yoshikata Koga

1994-01-01

9

Fast Computation of Solvation Free Energies with Molecular Density Functional Theory: Thermodynamic-Ensemble Partial Molar Volume Corrections  

E-print Network

Molecular Density Functional Theory (MDFT) offers an efficient implicit- solvent method to estimate molecule solvation free-energies whereas conserving a fully molecular representation of the solvent. Even within a second order ap- proximation for the free-energy functional, the so-called homogeneous reference uid approximation, we show that the hydration free-energies computed for a dataset of 500 organic compounds are of similar quality as those obtained from molecular dynamics free-energy perturbation simulations, with a computer cost reduced by two to three orders of magnitude. This requires to introduce the proper partial volume correction to transform the results from the grand canoni- cal to the isobaric-isotherm ensemble that is pertinent to experiments. We show that this correction can be extended to 3D-RISM calculations, giving a sound theoretical justifcation to empirical partial molar volume corrections that have been proposed recently.

Volodymyr P. Sergiievskyi; Guillaume Jeanmairet; Maximilien Levesque; Daniel Borgis

2014-06-11

10

Thermodynamics of aqueous zinc: Standard partial molar heat capacities and volumes of Zn 2+(aq) from 10 to 55°C  

NASA Astrophysics Data System (ADS)

The apparent molar heat capacities and volumes of aqueous Zn(ClO 4) 2 have been measured from 10-55°C in a Picker flow microcalorimeter and vibrating tube densimeter. The Guggenheim form of the extended Debye-Hückel equation was fitted to the experimental data, to obtain the following expressions for the standard-state properties from 10-55°C: C p0(Zn(ClO 4) 2, aq)/JK -1 mol -1 = 3850.8 - 150720/T-190 - 8.4956T (1) and V 0(Zn(ClO 4) 2, aq)/cm 3 mol -1 = 116.65 - 4073/T-190- 0.050374T . (2) The standard partial molar heat capacities and volumes for Zn 2+(aq) were extrapolated to higher temperatures by employing the Helgeson-Kirkham-Flowers (HKF) equations, amended to include a standardstate correction term. Gibbs energies calculated from the extrapolated heat capacity and volume functions are consistent with limited experimental data for the solubility of ZnO in acidic to near-neutral aqueous solutions at 200-300°C ( BOURCIER and BARNES, 1987).

Pan, Pujing; Tremaine, Peter R.

1994-11-01

11

Thermodynamic properties of alcohols in a micellar phase. Binding constants and partial molar volumes of pentanol in sodium dodecylsulfate micelles at 15, 25, and 35°C  

Microsoft Academic Search

Densities of the ternary system water-sodium dodecylsulfate (NaDS)-pentanol and of the binary systems butanol-octane and pentanol-octane were measured at 15, 25, and 35 °C. The apparent molar volume of pentanol in the ternary system was analyzed using a mass-action model for the alcohol distribution in micellar solutions. The partial molar volume of alcohol bound to the micelles and the ratio

Rosario De Lisi; Calogero Genova; Rosaria Testa; Vincenzo Turco Liveri

1984-01-01

12

Mass action model for solute distribution between water and micelles. Partial molar volumes of butanol and pentanol in dodecyl surfactant solutions  

Microsoft Academic Search

The densities of 1-butanol and 1-pentanol were measured in aqueous solutions of dodecyltrimethylammonium bromide and dodecyldimethylamine oxide and the partial molar volumes at infinite dilution of the alcohols in aqueous surfactants solutions were obtained. The observed trends of this quantity as a function of the surfactant concentration were rationalized using a mass-action model for the alcohol distribution between the aqueous

R. De Lisi; V. Turco Liveri; M. Castagnolo; A. Inglese

1986-01-01

13

Excess Chemical Potentials, Excess Partial Molar Enthalpies, Entropies, Volumes, and Isobaric Thermal Expansivities of Aqueous Glycerol at 25°C  

Microsoft Academic Search

The vapor pressures p the excess partial molar enthalpies of glycerol HGlyE the densities d and the thermal expansivities ap of aqueous glycerol were measured at 25°C. From the vapor pressure data, the excess chemical potential of H2O µWE was calculated, assuming that the partial pressure of glycerol pGly is negligibly small. The excess chemical potential of glycerol µ GlyE

Eric C. H. To; James V. Davies; Michael Tucker; Peter Westh; Christa Trandum; Kennth S. H. Suh; Yoshikata Koga

1999-01-01

14

Partial molar volumes and viscosity B-coefficients of arginine in aqueous glucose, sucrose and l-ascorbic acid solutions at T = 298.15 K  

Microsoft Academic Search

Densities and viscosities of arginine in (glucose+water), (sucrose+water) and (l-ascorbic acid+water) mixed solvents have been measured at T=298.15 K by an oscillating-tube densimeter and viscometer. Standard-state partial molar volume, hydration number and viscosity B-coefficients of arginine have been calculated. The transfer volumes from water to (sugar+water) or (l-ascorbic acid+water) mixed solvents have been obtained and discussed in terms of the

Changwei Zhao; Peisheng Ma; Jiding Li

2005-01-01

15

Standard partial molar volumes of some aqueous alkanolamines and alkoxyamines at temperatures up to 325 degrees C: functional group additivity in polar organic solutes under hydrothermal conditions.  

PubMed

Apparent molar volumes of dilute aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), N,N-dimethylethanolamine (DMEA), ethylethanolamine (EAE), 2-diethylethanolamine (2-DEEA), and 3-methoxypropylamine (3-MPA) and their salts were measured at temperatures from 150 to 325 degrees C and pressures as high as 15 MPa. The results were corrected for the ionization and used to obtain the standard partial molar volumes, Vo2. A three-parameter equation of state was used to describe the temperature and pressure dependence of the standard partial molar volumes. The fitting parameters were successfully divided into functional group contributions at all temperatures to obtain the standard partial molar volume contributions. Including literature results for alcohols, carboxylic acids, and hydroxycarboxylic acids yielded the standard partial molar volume contributions of the functional groups >CH-, >CH2, -CH3, -OH, -COOH, -O-, -->N, >NH, -NH2, -COO-Na+, -NH3+Cl-, >NH2+Cl-, and -->NH+Cl- over the range (150 degrees C partial molar volume of aqueous organic solutes composed of these groups at temperatures up to approximately 310 degrees C and pressures of 10-20 MPa to within a precision of +/-5 cm3 x mol(-1). The model could not be extended to higher temperatures because of uncertainties caused by thermal decomposition. At temperatures above approximately 250 degrees C, the order of the group contributions to Vo2 changes from that observed at 25 degrees C, to become increasingly consistent with the polarity of each functional group. The effect of the dipole moment of each molecule on the contribution to Vo2 from long-range solvent polarization was calculated from the multipole expansion of the Born equation using dipole moments estimated from restricted Hartree-Fock calculations with Gaussian 03 (Gaussian, Inc., Wallingford, CT) and the Onsager reaction-field approximation for solvent effects. Below 325 degrees C, the dipole contribution was found to be less than 2 cm3 x mol(-1) for all the solute molecules studied. At higher temperatures and pressures near steam saturation, the effect is much larger and may explain anomalies in functional group additivity observed in small, very polar solutes. PMID:18412415

Bulemela, E; Tremaine, Peter R

2008-05-01

16

Mass action model for solute distribution between water and micelles. Partial molar volumes of butanol and pentanol in dodecyl surfactant solutions  

SciTech Connect

Water-surfactant-solubilizate systems have attracted much attention in recent years since these systems in the presence of oil can lead to microemulsions that have important applications in oil recovery. In this light, the densities of 1-butanol and 1-pentanol were measured in aqueous solutions of dodecyltrimethylammonium bromide and dodecyldimethylamine oxide, and the partial molar volumes at infinite dilution of the alcohols in aqueous surfactant solutions were obtained. The observed trends of this quantity as a function of the surfactant concentration were rationalized using a mass-action model for the alcohol distribution between the aqueous and the micellar phase. At the same time, the model was revised to account for the alcohol effect on the surfactant micellization equilibrium. The partial molar volume of alcohols in the aqueous and in the micellar phases and the ratios between the binding constant and the aggregation number were calculated. These thermodynamic quantities are nearly the same in the two surfactants analyzed but differ appreciably from those in sodium dodecylsulfate. The apparent molar volume of surfactants in some hydroalcoholic solutions at fixed alcohol concentration were also calculated. In the micellization region the trend of this quantity as a function of the surfactant concentration shows a hump, which depends on the alcohol concentration and on the alcohol alkyl chain length. The alcohol extraction from the aqueous to the micellar phase due to the addition of the surfactant can account for the observed trends.

De Lisi, R.; Castagnolo, M.; Inglese, A.; Liveri, V.T.

1986-01-01

17

New density measurements on carbonate liquids and the partial molar volume of the CaCO 3 component  

Microsoft Academic Search

Density measurements on nine liquids in the CaCO 3–Li 2CO 3–Na 2CO 3–K 2CO 3 quaternary system were performed at 1 bar between 555 and 969 °C using the double-bob Archimedean method. Our density data on the end-member alkali carbonate liquids are in excellent agreement with the NIST standards compiled by Janz (1992). The results were fitted to a volume equation that

Qiong Liu; Rebecca A. Lange

2003-01-01

18

Cul3-mediated Nrf2 ubiquitination and ARE activation are dependent on the partial molar volume at position 151 of Keap1  

PubMed Central

SYNOPSIS Nrf2 is a transcription factor that activates transcription of a battery of cytoprotective genes by binding to the antioxidant response element (ARE). Nrf2 is repressed by the cysteine-rich Keap1 protein, which targets Nrf2 for ubiquitination and subsequent degradation by a Cul3-mediated ubiquitination complex. We find that modification of C151 of human Keap1 by mutation to a tryptophan relieves the repression by Keap1 and allows activation of the ARE by Nrf2. Keap1 C151W has a decreased affinity for Cul3, and can no longer serve to target Nrf2 for ubiquitination, though it retains its affinity for Nrf2. A series of 12 mutant Keap1 proteins, each containing a different residue at position 151, was constructed to explore the chemistry required for the effect. The series reveals that the extent to which Keap1 loses the ability to target Nrf2 for degradation, and hence the ability to repress ARE activation, correlates well with the partial molar volume of the residue. Other physico-chemical properties do not appear to contribute significantly to the effect. Based on this finding, a structural model is proposed whereby large residues at position 151 cause steric clashes that lead to alteration of the Keap1-Cul3 interaction. This model has significant implications for how electrophiles, which modify C151, disrupt the repressive function of Keap1. PMID:19489739

Eggler, Aimee L.; Small, Evan; Hannink, Mark; Mesecar, Andrew D.

2013-01-01

19

Cul3-mediated Nrf2 ubiquitination and antioxidant response element (ARE) activation are dependent on the partial molar volume at position 151 of Keap1.  

PubMed

Nrf2 (nuclear factor erythroid 2-related factor 2) is a transcription factor that activates transcription of a battery of cytoprotective genes by binding to the ARE (antioxidant response element). Nrf2 is repressed by the cysteine-rich Keap1 (kelch-like ECH-associated protein 1) protein, which targets Nrf2 for ubiquitination and subsequent degradation by a Cul3 (cullin 3)-mediated ubiquitination complex. We find that modification of Cys(151) of human Keap1, by mutation to a tryptophan, relieves the repression by Keap1 and allows activation of the ARE by Nrf2. The Keap1 C151W substitution has a decreased affinity for Cul3, and can no longer serve to target Nrf2 for ubiquitination, though it retains its affinity for Nrf2. A series of 12 mutant Keap1 proteins, each containing a different residue at position 151, was constructed to explore the chemistry required for this effect. The series reveals that the extent to which Keap1 loses the ability to target Nrf2 for degradation, and hence the ability to repress ARE activation, correlates well with the partial molar volume of the residue. Other physico-chemical properties do not appear to contribute significantly to the effect. Based on this finding, a structural model is proposed whereby large residues at position 151 cause steric clashes that lead to alteration of the Keap1-Cul3 interaction. This model has significant implications for how electrophiles which modify Cys(151), disrupt the repressive function of Keap1. PMID:19489739

Eggler, Aimee L; Small, Evan; Hannink, Mark; Mesecar, Andrew D

2009-08-15

20

Partial molar quantity of an intensive mother function.  

PubMed

A new formal definition is given to the partial molar quantity of a component i for an intensive mother function. We perturb the entire system by increasing the amount of the target component by ?n(i) keeping others constant and measure the response of the system in terms of an intensive mother function, ?, ??. We then define its partial molar quantity of the ith component, ?(i), as ?(i) = [???{?n(i)?(N + ?n(i))

Koga, Yoshikata

2012-09-28

21

Molarity  

NSDL National Science Digital Library

What determines the concentration of a solution? Learn about the relationships between moles, liters, and molarity by adjusting the amount of solute and solution volume. Change solutes to compare different chemical compounds in water.

Simulations, Phet I.; Chamberlain, Julia; Malley, Chris; Lancaster, Kelly; Parson, Robert; Perkins, Kathy

2012-02-20

22

Apparent Molar Volume and Apparent Molar Expansibility of Rubidium, Cesium, and Ammonium Cyclohexylsulfamate in Aqueous Solution  

Microsoft Academic Search

Summary.  The apparent molar volume of rubidium, caesium, and ammonium cyclohexylsulfamate was determined from the density data of their\\u000a aqueous solutions at 293.15, 298.15, 303.15, 313.15, 323.15, and 333.15?K. From the apparent molar volume, determined at various\\u000a temperatures, the apparent molar expansibility was calculated. The limiting apparent molar volume and apparent molar expansibility\\u000a were evaluated and apportioned into their ionic components.

Cveto Klofutar; Jaka Horvat; Darja Rudan-Tasic

2006-01-01

23

The Partly Molar Pregnancy That Is Not a Partial Mole  

Microsoft Academic Search

The presence of a fetus in a molar pregnancy is usually an indication that it is a partial, rather than a complete, hydatidiform mole. The underlying reason for this is a basic difference in the genetic composition of the 2 types of mole. Complete moles are ‘‘androgenetic’’ conceptions, i.e., their genome is entirely paternal in origin [1]. The total absence

Harshwardhan M. Thaker

2005-01-01

24

Oxygen from Hydrogen Peroxide. A Safe Molar Volume-Molar Mass Experiment.  

ERIC Educational Resources Information Center

Describes a molar volume-molar mass experiment for use in general chemistry laboratories. Gives background technical information, procedures for the titration of aqueous hydrogen peroxide with standard potassium permanganate and catalytic decomposition of hydrogen peroxide to produce oxygen, and a discussion of the results obtained in three…

Bedenbaugh, John H.; And Others

1988-01-01

25

Apparent Molar Volume and Apparent Molar Expansibility of Lithium, Sodium, Potassium, and Tetramethylammonium Cyclohexylsulfamate in Aqueous Solution  

Microsoft Academic Search

Summary. The apparent molar volume of lithium, sodium, potassium, and tetramethylammonium cyclohexylsulfamate was determined from the density data of their aqueous solutions at 293.15, 298.15, 303.15, 313.15, and 323.15?K. The apparent molar expansibility was calculated from the apparent molar volume at various temperatures. The limiting apparent molar volume and apparent molar expansibility were evaluated and divided into their ionic components.

Cveto Klofutar; Darja Rudan-Tasic

2005-01-01

26

Infinitely dilute partial molar properties of proteins from computer simulation.  

PubMed

A detailed understanding of temperature and pressure effects on an infinitely dilute protein's conformational equilibrium requires knowledge of the corresponding infinitely dilute partial molar properties. Established molecular dynamics methodologies generally have not provided a way to calculate these properties without either a loss of thermodynamic rigor, the introduction of nonunique parameters, or a loss of information about which solute conformations specifically contributed to the output values. Here we implement a simple method that is thermodynamically rigorous and possesses none of the above disadvantages, and we report on the method's feasibility and computational demands. We calculate infinitely dilute partial molar properties for two proteins and attempt to distinguish the thermodynamic differences between a native and a denatured conformation of a designed miniprotein. We conclude that simple ensemble average properties can be calculated with very reasonable amounts of computational power. In contrast, properties corresponding to fluctuating quantities are computationally demanding to calculate precisely, although they can be obtained more easily by following the temperature and/or pressure dependence of the corresponding ensemble averages. PMID:25325571

Ploetz, Elizabeth A; Smith, Paul E

2014-11-13

27

Molar crown thickness, volume, and development  

E-print Network

repre- sent a whole-tooth approach, and capture the distribution of enamel thickness across the entire on external cranial and dental features. Little is known about internal aspects of tooth structure, and confocal microscopy. Data on enamel thickness, crown volumes, and enamel develop- ment were compared

Smith, Tanya M.

28

On the apparent molar volumes of nonelectrolytes in water  

Microsoft Academic Search

Apparent molar volumes of aqueous solutions of argon and xenon have been calculated using a previously developed comprehensive equation of state for nonelectrolyte systems. The equation consists of a virial expansion truncated after the fourth virial coefficient and a closed-form term approximating higher coefficients. Mixing rules are based on the composition dependence of virial coefficients, which is known from statistical

Andrzej Anderko; John P. Chan; Kenneth S. Pitzer

1993-01-01

29

Excess Molar Volumes of Aqueous Solutions of Butylamine Isomers  

Microsoft Academic Search

Excess molar volumes (V ) and average thermal expansivities (?) of the systems, water (W) + n-butylamine (NBA), W + sec-butylamine (SBA), and W + tert-butylamine (TBA), have been calculated from the density data at temperatures ranging from 298.15–323.15 K. The V and ? values have been plotted as functions of mole fraction of amines. The systems show large negative

Muhammad A. Saleh; Shamim Akhtar; Ashiqur Rahman Khan

2000-01-01

30

Molar volumes of aqueous and ethylene glycol solutions of tetrahydrofuran  

NASA Astrophysics Data System (ADS)

The densities of ethylene glycol solutions of tetrahydrofuran (THF) with 0-20 mol % THF were measured at 20-60°C and atmospheric pressure to an accuracy of 5 × 10-5 g/cm3. The apparent molar volumes of THF in the solutions were calculated and their concentration and temperature dependences determined. The results were compared with the apparent molar volumes of THF in aqueous systems calculated from the literature data. Minima were found on the concentration dependence of the apparent volume of THF for both aqueous and ethylene glycol solutions and changed differently as the temperature increased. The data obtained were discussed from the standpoint of solvophobic effects in aqueous and ethylene glycol solutions of THF.

Rodnikova, M. N.; Gunina, M. A.; Makarov, D. M.; Egorov, G. I.; Val'Kovskaya, T. M.

2011-09-01

31

On the apparent molar volumes of nonelectrolytes in water  

SciTech Connect

Apparent molar volumes of aqueous solutions of argon and xenon have been calculated using a previously developed comprehensive equation of state for nonelectrolyte systems. The equation consists of a virial expansion truncated after the fourth virial coefficient and a closed-form term approximating higher coefficients. Mixing rules are based on the composition dependence of virial coefficients, which is known from statistical mechanics. The equation accurately represents vapor-liquid and gas-gas equilibria for the Ar + H[sub 2]O and Xe + H[sub 2]O systems over wide ranges of pressure and temperature using two binary parameters. With the binary parameters determined from phase equilibrium data, the equation accurately predicts apparent molar volumes V[sub [phi

Anderko, A.; Chan, J.P.; Pitzer, K.S. (Lawrence Berkeley Lab., CA (United States))

1993-04-01

32

Relationships between the molar volumes of mixtures of elements and their compounds  

Microsoft Academic Search

The molar volumes of stoichiometric mixtures of Group I–III metals and Group V–VII nonmetals are compared with the molar volumes\\u000a of MX compounds. The derivatives of the B-subgroup metals have the molar volumes larger than the mixtures. The compounds of\\u000a A-subgroup metals have smaller volumes than the mixtures. A crystal-chemical interpretation of this fact is advanced.

S. S. Batsanov

2006-01-01

33

Measurements and analysis of excess molar volumes for the ternary mixture MTBE + 1-pentanol + decane  

Microsoft Academic Search

Summary Densities at 298.15 K and atmospheric pressure have been measured, using a DMA 4500 Anton Paar densimeter, for the ternary mixture methyl tert-butyl ether (MTBE)+1-pentanol+decane and for the involved binary mixtures MTBE+1-pentanol and 1-pentanol+decane. The excess molar volumes for the binary mixture MTBE+decane was reported in an earlier work [1]. In addition, excess molar volumes were determined from the

P. V. Verdes; M. M. Mato; J. Salgado; J. L. Legido; M. I. Paz Andrade

2005-01-01

34

Partial specific volume of polyurea  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume D2 'Polymer Solutions - Physical Properties and their Relations I (Thermodynamic Properties: PVT -Data and miscellaneous Properties of polymer Solutions) of Volume 6 `Polymers' of Landolt-Börnstein - Group VIII `Advanced Materials and Technologies'.

Wohlfarth, Ch.

35

Partial specific volume of Pullulan  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume D2 'Polymer Solutions - Physical Properties and their Relations I (Thermodynamic Properties: PVT -Data and miscellaneous Properties of polymer Solutions) of Volume 6 `Polymers' of Landolt-Börnstein - Group VIII `Advanced Materials and Technologies'.

Wohlfarth, Ch.

36

Sealing versus partial caries removal in primary molars: a randomized clinical trial  

PubMed Central

Background The resin-based pit and fissure sealant is considered a successful tool in caries prevention, however there is a growing evidence of its use in controlling already established caries in posterior teeth. The aim of this clinical trial is to verify the efficacy of pit and fissure sealants in arresting dentinal caries lesions compared to partial excavation and restorative treatment in primary molar teeth. Methods Thirty six patients with occlusal cavitated primary molar reaching outer half of dentin were selected. The patients were randomly allocated into two groups: sealant application (experimental group – n?=?17) and restoration with composite resin (control group – n?=?19). Clinical and radiograph evaluation were performed after 6, 12 and 18 months. The chi-square test was used to verify the distribution of characteristics variables of the sample among the groups. The survival rate of treatments was evaluated using Kaplan–Meier survival and log-rank test. Fisher’s Exact and logistic regression tests were calculated in each evaluation period (??=?5%). Results The control group showed significantly better clinical survival after 18 months (p?=?0.0025). In both groups, no caries progression was registered on the radiographic evaluations. Conclusions Sealing had similar efficacy in the arrestment of caries progression of cavitated occlusal lesions compared to partial excavation of the lesions, even though the frequency of re-treatments was significantly higher in sealed lesions. Trial registration Registro Brasileiro de Ensaios Clínicos (ReBEC): RBR-9kkv53 PMID:24884684

2014-01-01

37

The Component Slope Linear Model for Calculating Intensive Partial Molar Properties: Application to Waste Glasses and Aluminate Solutions - 13099  

SciTech Connect

Partial molar properties are the changes occurring when the fraction of one component is varied while the fractions of all other component mole fractions change proportionally. They have many practical and theoretical applications in chemical thermodynamics. Partial molar properties of chemical mixtures are difficult to measure because the component mole fractions must sum to one, so a change in fraction of one component must be offset with a change in one or more other components. Given that more than one component fraction is changing at a time, it is difficult to assign a change in measured response to a change in a single component. In this study, the Component Slope Linear Model (CSLM), a model previously published in the statistics literature, is shown to have coefficients that correspond to the intensive partial molar properties. If a measured property is plotted against the mole fraction of a component while keeping the proportions of all other components constant, the slope at any given point on a graph of this curve is the partial molar property for that constituent. Actually plotting this graph has been used to determine partial molar properties for many years. The CSLM directly includes this slope in a model that predicts properties as a function of the component mole fractions. This model is demonstrated by applying it to the constant pressure heat capacity data from the NaOHNaAl(OH){sub 4}-H{sub 2}O system, a system that simplifies Hanford nuclear waste. The partial molar properties of H{sub 2}O, NaOH, and NaAl(OH){sub 4} are determined. The equivalence of the CSLM and the graphical method is verified by comparing results determined by the two methods. The CSLM model has been previously used to predict the liquidus temperature of spinel crystals precipitated from Hanford waste glass. Those model coefficients are re-interpreted here as the partial molar spinel liquidus temperature of the glass components. (authors)

Reynolds, Jacob G. [Washington River Protection Solutions, LLC, P.O. Box 850, Richland, WA 99352 (United States)] [Washington River Protection Solutions, LLC, P.O. Box 850, Richland, WA 99352 (United States)

2013-07-01

38

Raman studies of hydration of hydroxy complexes and the effect on standard partial molar heat capacities  

NASA Astrophysics Data System (ADS)

Raman spectroscopic studies of aqueous hydroxy complexes B(OH) 3, B(OH) 42-, Al(OH) 4-, Zn(OH) 42-, and their deuterated analogues provide compelling evidence for the presence of strong hydrogen bonding of water in the outer solvation sphere to the oxygen of the hydroxy ligand in the first coordination sphere. The deuterated complexes are more strongly hydrogen bonded than the hydrogen complexes. The fact that these hydrogen-bonding effects for the hydroxy borates are much more pronounced than for the aluminate and zincate anions can account for the unexpectedly large differences in the standard partial molar heat capacities of B(OH) 4- and A1(OH) 4-. The extension of semi-empirical solvation models based on the Born approximation for aqueous hydrolyzed species will need to consider the rather large and specific effect of hydrogen bonding of water to the hydroxide ion.

Brooker, Murray H.; Tremaine, Peter R.

1992-06-01

39

Partial molar enthalpies and reaction enthalpies from equilibrium molecular dynamics simulation  

NASA Astrophysics Data System (ADS)

We present a new molecular simulation technique for determining partial molar enthalpies in mixtures of gases and liquids from single simulations, without relying on particle insertions, deletions, or identity changes. The method can also be applied to systems with chemical reactions. We demonstrate our method for binary mixtures of Weeks-Chandler-Anderson particles by comparing with conventional simulation techniques, as well as for a simple model that mimics a chemical reaction. The method considers small subsystems inside a large reservoir (i.e., the simulation box), and uses the construction of Hill to compute properties in the thermodynamic limit from small-scale fluctuations. Results obtained with the new method are in excellent agreement with those from previous methods. Especially for modeling chemical reactions, our method can be a valuable tool for determining reaction enthalpies directly from a single MD simulation.

Schnell, Sondre K.; Skorpa, Ragnhild; Bedeaux, Dick; Kjelstrup, Signe; Vlugt, Thijs J. H.; Simon, Jean-Marc

2014-10-01

40

Partial molar enthalpies and reaction enthalpies from equilibrium molecular dynamics simulation.  

PubMed

We present a new molecular simulation technique for determining partial molar enthalpies in mixtures of gases and liquids from single simulations, without relying on particle insertions, deletions, or identity changes. The method can also be applied to systems with chemical reactions. We demonstrate our method for binary mixtures of Weeks-Chandler-Anderson particles by comparing with conventional simulation techniques, as well as for a simple model that mimics a chemical reaction. The method considers small subsystems inside a large reservoir (i.e., the simulation box), and uses the construction of Hill to compute properties in the thermodynamic limit from small-scale fluctuations. Results obtained with the new method are in excellent agreement with those from previous methods. Especially for modeling chemical reactions, our method can be a valuable tool for determining reaction enthalpies directly from a single MD simulation. PMID:25318729

Schnell, Sondre K; Skorpa, Ragnhild; Bedeaux, Dick; Kjelstrup, Signe; Vlugt, Thijs J H; Simon, Jean-Marc

2014-10-14

41

Excess molar volumes for CO sub 2 -CH sub 4 -N sub 2 mixtures  

SciTech Connect

Vibrating-tube densimetry experiments are being performed to determine the excess molar volumes of single-phase CO{sub 2}-CH{sub 4}-N{sub 2} gas mixtures at pressures as high as 3500 bars and temperatures up to 500{degrees}C. In our initial experiments, we determined the P-V-T properties of: (1) CO{sub 2}-CH{sub 4}, CO{sub 2}N{sub 2}, CH{sub 4}-N{sub 2}, and CO{sub 2}-CH{sub 4}-N{sub 2} mixtures at 1000 bars. 50 {degrees}C: and (2) CO{sub 2}-CH{sub 4} mixtures from 100 to 1000 bars at 100{degrees}C. Excess molar volumes in the binary subsystems are very accurately represented by two-parameter Margules equations. Experimentally determined excess molar volumes are in fair to poor agreement with predictions from published equations of state. Geometric projection techniques based on binary system data yield from published equations of state. Geometric projection techniques based on binary system data yield calculated excess molar volume for CO{sub 2}-CH{sub 4}-N{sub 2} mixtures that are in good agreement with our experimental data. 7 refs., 8 figs.

Seitz, J.C. (Oak Ridge National Lab., TN (United States) Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Geological Sciences); Blencoe, J.G.; Joyce, D.B. (Oak Ridge National Lab., TN (United States)); Bodnar, R.J. (Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Geological Sciences)

1992-01-01

42

Partial molecular volumes of lipids and cholesterol  

PubMed Central

Volumetric measurements are reported for fully hydrated lipid/cholesterol bilayer mixtures using the neutral flotation method. Apparent specific volume data were obtained with the lipids DOPC, POPC and DMPC at T = 30 °C, DPPC at 50 °C, and brain sphingomyelin (BSM) at 45 and 24 °C for mole fractions of cholesterol x from 0 to 0.5. Unlike previous cholesterol mixture studies, we converted our raw data to partial molecular volume VL of the lipid and VC of the cholesterol. The partial molecular volumes were constant for POPC and DOPC as x was varied, but had sharp breaks for the other lipids at values of xC near 0.25 ± 0.05. Results for x < xC clearly exhibit the condensation effect of cholesterol on DPPC, DMPC and BSM when measured at temperatures above their main transition temperatures TM. The break points at xC are compared to phase diagrams in the literature. For x > xC the values of the partial molecular volumes of cholesterol clustered near 630 ± 10 Å3 in all the lipids when measured for T > TM; we suggest that this is the most appropriate measure of the bare volume of cholesterol in lipid bilayers. PMID:16737691

Greenwood, Alexander I.; Tristram-Nagle, Stephanie; Nagle, John F.

2009-01-01

43

Spectrum of excess partial molar absorptivity. Part II: a near infrared spectroscopic study of aqueous Na-halides.  

PubMed

Our earlier thermodynamic studies suggested that F(-) and Cl(-) form hydration shells with the hydration number 14 ± 2 and 2.3 ± 0.6, respectively, and leave the bulk H(2)O away from hydration shells unperturbed. Br(-) and I(-), on the other hand, form hydrogen bonds directly with the momentarily existing hydrogen bond network of H(2)O, and retard the degree of entropy-volume cross fluctuation inherent in liquid H(2)O. The effect of the latter is stronger for I(-) than Br(-). Here we seek additional information about this qualitative difference between Cl(-) and (Br(-) and I(-)) pair by near infrared (NIR) spectroscopy. We analyze the ?(2) + ?(3) band of H(2)O in the range 4600-5500 cm(-1) of aqueous solutions of NaCl, NaBr and NaI, by a new approach. From observed absorbance, we calculate excess molar absorptivity, ?(E), excess over the additive contributions of solute and solvent. ?(E) thus contains information about the effect of inter-molecular interactions in the ?(2) + ?(3) spectrum. The spectrum of ?(E) shows three bands; two negative ones at 5263 and 4873 cm(-1), and the positive band at 5123 cm(-1). We then define and calculate the excess partial molar absorptivity of each salt, ?(E)(salt). From the behaviour of ?(E)(salt) we suggest that the negative band at 5263 cm(-1) represents free H(2)O without much hydrogen bonding under the influence of local electric field of ions. Furthermore, from a sudden change in the x(salt) (mole fraction of salt) dependence of ?(E)(salt), we suggest that there is an ion-pairing in x(salt) > 0.032, 0.036, and 0.04 for NaCl, NaBr and NaI respectively. The positive band of ?(E) at 5123 cm(-1) is attributed to a modestly organized hydrogen bond network of H(2)O (or liquid-likeness), and the x(salt) dependence of ? indicated a qualitative difference in the effect of Cl(-) from those of Br(-) and I(-). Namely, the values of ?(E)(salt) stay constant for Cl(-) but those for Br(-) and I(-) decrease smoothly on increasing the salt mole fraction. The mole fraction dependence of ?(E)(salt) at the 4873 cm(-1) band, due to ice-likeness in H(2)O, shows a subtle difference between Cl(-) and (Br(-), I(-)) pair. PMID:22358251

Sebe, Fumie; Nishikawa, Keiko; Koga, Yoshikata

2012-04-01

44

Partial volume simulation in software breast phantoms  

NASA Astrophysics Data System (ADS)

A modification to our previous simulation of breast anatomy is proposed, in order to improve the quality of simulated projections generated using software breast phantoms. Anthropomorphic software breast phantoms have been used for quantitative validation of breast imaging systems. Previously, we developed a novel algorithm for breast anatomy simulation, which did not account for the partial volume (PV) of various tissues in a voxel; instead, each phantom voxel was assumed to contain single tissue type. As a result, phantom projection images displayed notable artifacts near the borders between regions of different materials, particularly at the skin-air boundary. These artifacts diminished the realism of phantom images. One solution is to simulate smaller voxels. Reducing voxel size, however, extends the phantom generation time and increases memory requirements. We achieved an improvement in image quality without reducing voxel size by the simulation of PV in voxels containing more than one simulated tissue type. The linear x-ray attenuation coefficient of each voxel is calculated by combining attenuation coefficients proportional to the voxel subvolumes occupied by the various tissues. A local planar approximation of the boundary surface is employed, and the skin volume in each voxel is computed by decomposition into simple geometric shapes. An efficient encoding scheme is proposed for the type and proportion of simulated tissues in each voxel. We illustrate the proposed methodology on phantom slices and simulated mammographic projections. Our results show that the PV simulation has improved image quality by reducing quantization artifacts.

Chen, Feiyu; Pokrajac, David; Shi, Xiquan; Liu, Fengshan; Maidment, Andrew D. A.; Bakic, Predrag R.

2012-03-01

45

Determination of the Relative Partial Molar Enthalpy of Decyldimethylphospine Oxide in H 2O and D 2O at 25°C  

Microsoft Academic Search

The relative partial molar enthalpy of decyldimethylphosphine oxide has been determined in H2O and D2O from infinite dilution to about 8 mm at 25°C. The shapes of the resulting curves resemble those previously reported forionicbut notnonionicsurfactants and are inconsistent with existing models of micelle formation. The enthalpy of micelle formation (corresponding to the maximum value of the relative partial molar

Gordon C. Kresheck

1997-01-01

46

Excess molar volumes, viscosity, refractive index, and Gibbs energy of activation of binary biodiesel + benzene, and biodiesel + toluene mixtures at 298.15 and 303.15 K  

Microsoft Academic Search

Excess molar volumes (V\\u000a E), viscosities, refractive index, and Gibbs energies were evaluated for binary biodiesel + benzene and toluene mixtures at\\u000a 298.15 and 303.15 K. The excess molar volumes V\\u000a E were determined from density, while the excess Gibbs free energy of activation G*E was calculated from viscosity deviation ??. The excess molar volume (V\\u000a E), viscosity deviation (??),

Ufuk Sancar Vural; Fatih Durmaz; Ozcan Kocyigit; Hasan Kocyigit; V. Muradoglu; Beril Akin

2008-01-01

47

Correction for Partial Volume Effects in PET: Principle and Validation  

Microsoft Academic Search

The accuracy of PET for measuring regional radiotracer concentra tions in the human brain is limited by the finite resolution capability of the scanner and the resulting partial volume effects (PVEs). We designed a new algorithm to correct for PVEs by characterizing the geometric interaction between the PETsystem and the brain activity distribution. Methods: The partial volume correction (PVC) algo

O. G. Rousset; Yilong Ma; Alan C. Evans

1998-01-01

48

Volume analysis of heat-induced cracks in human molars: A preliminary study  

PubMed Central

Context: Only a few methods have been published dealing with the visualization of heat-induced cracks inside bones and teeth. Aims: As a novel approach this study used nondestructive X-ray microtomography (micro-CT) for volume analysis of heat-induced cracks to observe the reaction of human molars to various levels of thermal stress. Materials and Methods: Eighteen clinically extracted third molars were rehydrated and burned under controlled temperatures (400, 650, and 800°C) using an electric furnace adjusted with a 25°C increase/min. The subsequent high-resolution scans (voxel-size 17.7 ?m) were made with a compact micro-CT scanner (SkyScan 1174). In total, 14 scans were automatically segmented with Definiens XD Developer 1.2 and three-dimensional (3D) models were computed with Visage Imaging Amira 5.2.2. The results of the automated segmentation were analyzed with an analysis of variance (ANOVA) and uncorrected post hoc least significant difference (LSD) tests using Statistical Package for Social Sciences (SPSS) 17. A probability level of P < 0.05 was used as an index of statistical significance. Results: A temperature-dependent increase of heat-induced cracks was observed between the three temperature groups (P < 0.05, ANOVA post hoc LSD). In addition, the distributions and shape of the heat-induced changes could be classified using the computed 3D models. Conclusion: The macroscopic heat-induced changes observed in this preliminary study correspond with previous observations of unrestored human teeth, yet the current observations also take into account the entire microscopic 3D expansions of heat-induced cracks within the dental hard tissues. Using the same experimental conditions proposed in the literature, this study confirms previous results, adds new observations, and offers new perspectives in the investigation of forensic evidence. PMID:25125923

Sandholzer, Michael A.; Baron, Katharina; Heimel, Patrick; Metscher, Brian D.

2014-01-01

49

Excess molar volumes for CO{sub 2}-CH{sub 4}-N{sub 2} mixtures  

SciTech Connect

Vibrating-tube densimetry experiments are being performed to determine the excess molar volumes of single-phase CO{sub 2}-CH{sub 4}-N{sub 2} gas mixtures at pressures as high as 3500 bars and temperatures up to 500{degrees}C. In our initial experiments, we determined the P-V-T properties of: (1) CO{sub 2}-CH{sub 4}, CO{sub 2}N{sub 2}, CH{sub 4}-N{sub 2}, and CO{sub 2}-CH{sub 4}-N{sub 2} mixtures at 1000 bars. 50 {degrees}C: and (2) CO{sub 2}-CH{sub 4} mixtures from 100 to 1000 bars at 100{degrees}C. Excess molar volumes in the binary subsystems are very accurately represented by two-parameter Margules equations. Experimentally determined excess molar volumes are in fair to poor agreement with predictions from published equations of state. Geometric projection techniques based on binary system data yield from published equations of state. Geometric projection techniques based on binary system data yield calculated excess molar volume for CO{sub 2}-CH{sub 4}-N{sub 2} mixtures that are in good agreement with our experimental data. 7 refs., 8 figs.

Seitz, J.C. [Oak Ridge National Lab., TN (United States)]|[Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Geological Sciences; Blencoe, J.G.; Joyce, D.B. [Oak Ridge National Lab., TN (United States); Bodnar, R.J. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Geological Sciences

1992-04-01

50

Excess Molar Volumes and Thermal Expansivities of Aqueous Solutions of Dimethylsulfoxide, Tetrahydrofuran and 1,4Dioxane  

Microsoft Academic Search

Densities, ? , of the systems water (W) + dimethylsulfoxide (DMSO), W + tetrahydrofuran (THF) and W + 1,4-dioxane (DO) have been determined in the temperature range 303.15-323.15 K. Excess molar volumes, $V_m^E $ , have been found to be negative and large in magnitude. Thermal expansivities, f , and excess thermal expansivities, f E , have been calculated. Densities,

Muhammad A. Saleh; Shamim Akhtar; M. Shamsuddin Ahmed; Mohammad Hemayet Uddin

2002-01-01

51

Excess molar volumes of mixtures of hexane + natural oils from 298.15 to 313.15 K  

SciTech Connect

Excess molar volume data for mixtures containing hexane with three edible oils: olive, corn, and pip of grape have been determined from density measurements at various temperatures between 298.15 and 313.15 K using a vibrating tube densimeter. Results have been correlated by the Redlich-Kister equation. Systems showed negative deviations from ideality in the whole composition range.

Gonzalez, C.; Resa, J.M.; Ruiz, A.; Gutierrez, J.I. [Univ. del Pais Vasco, Vitoria (Spain). Dept. of Chemical Engineering] [Univ. del Pais Vasco, Vitoria (Spain). Dept. of Chemical Engineering

1997-03-01

52

Trial shows partial caries removal is an effective technique in primary molars.  

PubMed

DesignRandomised controlled trial in a university setting.InterventionChildren aged three to eight years, with at least one molar with an acute, deep carious lesion into the dentine were recruited. Treatment took place under rubber dam with decayed dentine being removed completely from the lateral walls of cavities in both groups using round burs operated at low speed. TCR or PCR was then performed in the pulpal wall of each tooth. After caries removal teeth were restored with calcium hydroxide cement and composite resin. Teeth with pulpal exposure were pulpotomised using ferric sulphate.Outcome measureThe presence of a fistula, swelling, spontaneous pain and mobility not compatible with root resorption were considered to be clinical signs of failure. Radiolucency at the furcation or in the periapical region and internal or external pathological resorption were considered to be radiographic signs of failure.ResultsOne hundred and twenty-four teeth in 51 patients were randomised. In the TCR group there were 57 teeth and 38 patients, with 41 patients and 67 teeth in the PCR group. Three patients (four teeth; one PCR and three TCR) dropped out leaving 120 teeth (PCR: n = 66; TCR: n = 54) for analysis. In the TCR group 27.5% (15) teeth in 13 children had pulp exposure compared with one tooth in one child in the PCR group (2%). The mean operative time was significantly higher for TCR (28.1 min; 95% CI: 23.6-32.6 min) than for PCR (17.9 min; 95% CI: 16.3-19.5 min). There was no statistical difference in success rates at 24 months between the groups. The success rate in the TCR group was 96%; (95% CI: 85-99%) compared with 92%; (95% CI: 81-96%) in the PCR group.ConclusionsThe clinical and radiographic success rates of PCR and TCR in primary teeth with deep carious lesions were high and did not differ significantly, indicating that PCR is a reliable minimally invasive approach in primary teeth and that the retention of carious dentine does not interfere with pulp vitality. Moreover, PCR provided other clinically relevant advantages over TCR, especially lower incidence of pulp exposure and lower operative time. PMID:25343394

Santamaria, Ruth; Innes, Nicola

2014-09-01

53

Partial specific volume of cellulose diacetate  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume D2 'Polymer Solutions - Physical Properties and their Relations I (Thermodynamic Properties: PVT -Data and miscellaneous Properties of polymer Solutions) of Volume 6 `Polymers' of Landolt-Börnstein - Group VIII `Advanced Materials and Technologies'.

Wohlfarth, Ch.

54

Molecular analysis of 16S rRNA genes identifies potentially periodontopathogenic bacteria and archaea in the plaque of partially-erupted third molars  

Microsoft Academic Search

PurposeSmall subunit rRNA sequencing and phylogenetic analysis were used to identify cultivable and uncultivable micro-organisms present in dental plaque of symptomatic and asymptomatic partially-erupted third molars to determine the prevalence of putative periodontopathogens in pericoronal sites.

J. M. Mansfield; J. H. Campbell; A. R. Bhandari; A. M. Jesionowski; M. M. Vickerman

55

Apparent Molar Volume, Heat Capacity, and Conductance of Lithium Bis (trifluoromethylsulfone)imide in Glymes and Other Aprotic Solvents  

Microsoft Academic Search

Lithium bis(trifluoromethylsulfone)imide (LiTFSI) is a promising electrolyte for high-energy lithium batteries due to its high solubility in most solvents and electrochemical stability. To characterize this electrolyte in solution, its conductance and apparent molar volume and heat capacity were measured over a wide range of concentration in glymes, tetraethylsulfamide (TESA), acetonitrile, ?-butyrolactone, and propylene carbonate at 25°C and were compared with

Dany Brouillette; Gérald Perron; Jacques E. Desnoyers

1998-01-01

56

Estimation of the acentric factor and the liquid molar volume at 298 K using a new group contribution method  

Microsoft Academic Search

The method of Constantinou and Gani [Constantinou, L. and Gani, R., 1994. A new group contribution method for the estimation of properties of pure compounds. AIChE J., 40(10): 1697–1710] is extended to the estimation of the acentric factor and the liquid molar volume at 298 K. Thus, it now allows reliable prediction of all the common corresponding-state physical properties. In

Leonidas Constantinou; Rafiqul Gani; John P. O'Connell

1995-01-01

57

Molecular polarizability of organic compounds and their complexes: LII. Molar volumes of polymeric compounds in solutions, extrapolated to infinite dilution, and steric structure of their molecules  

Microsoft Academic Search

The molar volumes in solutions at infinite dilution were determined for a series of vinyl, glycol, isoprene, and cyclopentadiene\\u000a polymers and oligomers with various degrees of polymerization. An additive analysis of the molar volumes showed that molecules\\u000a of vinyl, ethylene glycol, and isoprene polymers exist in solutions in elongated helical conformations. In the majority of\\u000a polymer molecules, except polystyrenes, polyisoprenes,

S. B. Bulgarevich; T. V. Burdastykh; M. V. Boiko

2007-01-01

58

Determination of the Relative Partial Molar Enthalpy of Decyldimethylphospine Oxide in H2O and D2O at 25°C  

PubMed

The relative partial molar enthalpy of decyldimethylphosphine oxide has been determined in H2O and D2O from infinite dilution to about 8 mm at 25°C. The shapes of the resulting curves resemble those previously reported for ionic but not nonionic surfactants and are inconsistent with existing models of micelle formation. The enthalpy of micelle formation (corresponding to the maximum value of the relative partial molar enthalpy of the surfactant) was 12,900 ± 200 cal/mol in H2O and 10,600 ± 200 cal/mol in D2O. The cmc was lower in D2O than in H2O as expected (3.64 versus 4.2 mm). PMID:9073432

Kresheck

1997-03-15

59

Hygrometer for Detecting Water in Partially Enclosed Volumes  

NASA Technical Reports Server (NTRS)

A portable hygrometer has been devised to implement a pre-existing technique for detecting water trapped in partially enclosed volumes that may be difficult to reach and cannot be examined directly. The technique is based on the fact that eventually the air in such a volume becomes saturated or nearly so. The technique is straightforward: One measures the relative humidity and temperature of both the ambient air and a sample of air from the enclosed volume. If the relative humidity of the sample is significantly greater than that of the ambient air and/or if the sample is at or close to the dew point, then it can be concluded that water is trapped in the volume. Of course, the success of this technique depends on the existence of an access hole through which one can withdraw some air from the enclosed volume.

Youngquist, Robert C.; Surma, Jan; Parks, Steve

2005-01-01

60

Densities and excess molar volumes for mixtures of methanol with other alcohols at temperatures (288.15–313.15 K)  

Microsoft Academic Search

Densities have been measured for the binary mixtures of methanol with ethanol, isomers of propanol and butanol over the entire\\u000a composition range at 288.15, 293.15, 298.15, 303.15, 308.15, 313.15 K. The density data have been used to calculate the molar\\u000a volumes, thermal expansion coefficients and their excess values. The excess parameters have been fitted to the Redlich–Kister\\u000a polynomial equation. The values

Agnieszka Boru?; Ma?gorzata ?urada; Adam Bald

2010-01-01

61

Densities, molar volumes, cubic expansion coefficients, and isothermal compressibilities of 1-alkanols from 323. 15 K to 373. 15 K and pressures up to 10 MPa  

SciTech Connect

Densities of six alcohols, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, and 1-dodecanol, in the liquid state have been measured with a vibrating-tube densimeter from 323.15 to 373.15 K at pressures up to 10 MPa. Molar volumes (derived from the densities) have been fitted to polynomials as a function of temperature and pressure. Cubic expansion coefficients and isothermal compressibilities have been derived from molar volumes as a function of temperature and pressure. The results have also been compared with the available literature values.

Garg, S.K.; Banipal, T.S.; Ahluwalia, J.C. (Indian Inst. of Tech., New Delhi (India))

1993-04-01

62

The Molar Volume of FeO-MgO-Fe2O3-Cr2O3-Al2O3-TiO2 Spinels  

NASA Astrophysics Data System (ADS)

A new model of molar volume has been calibrated in the spinel supersystem (Mg,Fe2+)(Al,Cr,Fe3+)2O4 - (Mg,Fe2+)2TiO4. A total of 832 X-ray and neutron diffraction experiments performed on spinels at ambient and in situ high-P, T conditions (from the American Mineralogist Crystal Structure Database (Downs and Hall-Wallace, 2003) and other sources) were used to calibrate end-member equations of state and an excess volume model for this system. The effect on molar volume of cation ordering over the octahedral and tetrahedral sites is captured with linear dependence on Mg2+, Al3+, and Fe3+ site occupancy terms. We allowed standard state volumes and coefficients of thermal expansion of the end members to vary within their uncertainties during extraction of the mixing properties, in order to achieve the best fit. Published equations of states of the various spinel end members were analyzed to obtain optimal values of the bulk modulus and its pressure derivative, for each explicit end member. For any spinel composition in the supersystem, the model molar volume is obtained by adding excess volume and cation order-dependent terms to a linear combination of the five end member volumes, estimated at pressure and temperature using the high-T Vinet equation of state. The model has a total of 31 parameters and fits nearly all experiments to within 0.02 J/bar/mol, or better than 0.5% in volume. The model is compared to the current MELTS (Ghiorso and Sack, 1995; Ghiorso et al., 2002) spinel model with a demonstration of the impact of the model difference on the estimated spinel-garnet lherzolite transition pressure. Our primary motivation in this work is the development of a comprehensive spinel molar volume model for use in calibration of activity-composition models of garnet and pyroxene solid solutions. The thermodynamic models, along with a new silicate liquid equation of state, will be incorporated into the next generation MELTS model, xMELTS. The new solid solution models will include some minor components, including Ti4+ and Cr3+. Because most constraints on the activity of garnet and pyroxene at high-P are derived from experiments with coexisting spinel, we must be confident in the ability of our spinel model to realistically reproduce thermodynamic behavior over all applicable compositions. Additionally, producing a spinel molar volume model calibrated with recent in situ high-P, T diffraction data is crucial to our ability to accurately model the spinel-garnet transition in Earth's upper mantle. For example, we recently calibrated Cr-Al exchange equilibria for garnet and spinel. When this new calibration is used with the current MELTS model, a region of garnet-spinel coexistence in lherzolites is predicted with width in pressure comparable to experimental constraints. The transition occurs, however, at the unexpectedly low pressure of ~1.7 GPa. The improved model of spinel molar volume presented here, along with a new garnet molar volume model in the system FeO-MgO-CaO-Fe2O3-Cr2O3-Al2O3-TiO2-Na2O-SiO2 currently being calibrated, will enable coupled recalibration of the garnet and pyroxene models to match both the absolute pressure and width of this key transition in mantle lithology.

Hamecher, E. A.; Antoshechkina, P. M.; Ghiorso, M. S.; Asimow, P. D.

2011-12-01

63

Densities and excess molar volumes of formic acid, acetic acid and propionic acid in pure water and in water?+?Surf Excel solutions at different temperatures  

Microsoft Academic Search

Densities, ? of the systems formic acid, acetic acid and propionic acid in water and in 0.05% and 0.1% Surf Excel (SE) solutions in water were measured at temperatures 303.15, 308.15, 313.15, 318.15 and 323.15?K respectively covering the whole composition range. Excess molar volumes, for the systems were found to be negative and their values were found to increase with

M. A. Motin; M. H. Kabir; E. M. Huque

2005-01-01

64

Partial volume effect modeling for segmentation and tissue classification of brain magnetic resonance images: A review  

PubMed Central

Quantitative analysis of magnetic resonance (MR) brain images are facilitated by the development of automated segmentation algorithms. A single image voxel may contain of several types of tissues due to the finite spatial resolution of the imaging device. This phenomenon, termed partial volume effect (PVE), complicates the segmentation process, and, due to the complexity of human brain anatomy, the PVE is an important factor for accurate brain structure quantification. Partial volume estimation refers to a generalized segmentation task where the amount of each tissue type within each voxel is solved. This review aims to provide a systematic, tutorial-like overview and categorization of methods for partial volume estimation in brain MRI. The review concentrates on the statistically based approaches for partial volume estimation and also explains differences to other, similar image segmentation approaches.

Tohka, Jussi

2014-01-01

65

FMDP Reactor Alternative Summary Report: Volume 3 - partially complete LWR alternative  

SciTech Connect

The Department of Energy Office of Fissile Materials Disposition (DOE/MD) initiated a detailed analysis activity to evaluate each of ten plutonium disposition alternatives that survived an initial screening process. This document, Volume 3 of a four volume report summarizes the results of these analyses for the partially complete LWR (PCLWR) reactor based plutonium disposition alternative.

Greene, S.R.; Fisher, S.E.; Bevard, B.B. [and others

1996-09-01

66

Effect of Lumpectomy Cavity Volume Change on the Clinical Target Volume for Accelerated Partial Breast Irradiation: A Deformable Registration Study  

SciTech Connect

Purpose: Previous studies have shown that lumpectomy cavity volumes can change significantly in the weeks following surgery. The effect of this volume change on the surrounding tissue that constitutes the clinical target volume (CTV) for accelerated partial breast irradiation and boost treatment after whole breast irradiation has not been previously studied. In the present study, we used deformable registration to estimate the effect of lumpectomy cavity volume changes on the CTV for accelerated partial breast irradiation and discuss the implications for target construction. Methods and Materials: The data from 13 accelerated partial breast irradiation patients were retrospectively analyzed. Deformable registration was used to propagate contours from the initial planning computed tomography scan to a later computed tomography scan acquired at the start of treatment. The changes in cavity volume and CTV, distance between cavity and CTV contours (i.e., CTV margin), and CTV localization error after cavity registration were determined. Results: The mean {+-} standard deviation change in cavity volume and CTV between the two computed tomography scans was -35% {+-} 23% and -14% {+-} 12%, respectively. An increase in the cavity-to-CTV margin of 2 {+-} 2 mm was required to encompass the CTV, and this increase correlated with the cavity volume change. Because changes in the cavity and CTV were not identical, a localization error of 2-3 mm in the CTV center of mass occurred when the cavity was used as the reference for image guidance. Conclusion: Deformable registration suggested that CTV margins do not remain constant as the cavity volume changes. This finding has implications for planning target volume and CTV construction.

Kim, Leonard H., E-mail: lkim@beaumonthospitals.co [Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI (United States); DeCesare, Sam; Vicini, Frank; Yan Di [Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI (United States)

2010-11-15

67

Partial volume correction and image analysis methods for intersubject comparison of FDG-PET studies  

NASA Astrophysics Data System (ADS)

Partial volume effect is an artifact mainly due to the limited imaging sensor resolution. It creates bias in the measured activity in small structures and around tissue boundaries. In brain FDG-PET studies, especially for Alzheimer's disease study where there is serious gray matter atrophy, accurate estimate of cerebral metabolic rate of glucose is even more problematic due to large amount of partial volume effect. In this dissertation, we developed a framework enabling inter-subject comparison of partial volume corrected brain FDG-PET studies. The framework is composed of the following image processing steps: (1)MRI segmentation, (2)MR-PET registration, (3)MR based PVE correction, (4)MR 3D inter-subject elastic mapping. Through simulation studies, we showed that the newly developed partial volume correction methods, either pixel based or ROI based, performed better than previous methods. By applying this framework to a real Alzheimer's disease study, we demonstrated that the partial volume corrected glucose rates vary significantly among the control, at risk and disease patient groups and this framework is a promising tool useful for assisting early identification of Alzheimer's patients.

Yang, Jun

2000-12-01

68

Molar and excess volumes of liquid In-Sb, Mg-Sb, and Pb-Sb alloys  

SciTech Connect

By a direct Archimedes' technique, volumetric data were obtained for liquid In, Mg, Pb, and Sb and mixtures of In-Sb, Mg-Sb, and Pb-Sb. In this paper the excess volumes for the alloys studied are presented and discussed.

Hansen, A.R.; Kaminski, M.A. (Dept. of Chemical Engineering, Univ. of Illinois, Urbana, IL (US)); Eckert, C.A. (School of Chemical Engineering, Georgia Inst. of Technology, Atlanta, GA (US))

1990-04-01

69

Using Microcomputers in the Physical Chemistry Laboratory: A Partial Molal Volumes Experiment.  

ERIC Educational Resources Information Center

Describes a computer program used in an experiment in which the partial molal volumes of sodium chloride solutions are calculated as a function of concentration from densities measured with a pycnometer. The complete program listing (also available from the author on disk) and a sample run are included. (JN)

Venugopalan, Mundiyath

1986-01-01

70

Chemistry and Physics of Lipids 143 (2006) 110 Partial molecular volumes of lipids and cholesterol  

E-print Network

Chemistry and Physics of Lipids 143 (2006) 1­10 Partial molecular volumes of lipids and cholesterol Available online 28 April 2006 Abstract Volumetric measurements are reported for fully hydrated lipid/cholesterol for mole fractions of cholesterol x from 0 to 0.5. Unlike previous cholesterol mixture studies, we

Nagle, John F.

71

Characterization of PET partial volume corrections for variable myocardial wall thicknesses  

Microsoft Academic Search

Limited scanner resolution and cardiac motion contribute to partial volume (PV) averaging of positron emission tomography (PET) images. An extravascular (EV) density image, created from the subtraction of a blood pool (BP) from a transmission (TX) image can be used to estimate PV losses in the myocardium (MYO). A phantom emulating the left ventricle myocardium, with a variable wall thickness

Richard W. Wassenaar; Robert A. deKemp

2006-01-01

72

Characterization of PET partial volume corrections for variable myocardial wall thicknesses  

Microsoft Academic Search

Limited scanner resolution and cardiac motion contribute to partial volume (PV) averaging of PET images. An extravascular (EV) density image, created from the subtraction of a blood pool (BP) from a transmission (TX) image can be used to estimate PV losses in the myocardium (MYO). A phantom emulating the left ventricle myocardium, with a variable wall thickness (5 mm to

Richard W. Wassenaar; Robert A. deKemp

2004-01-01

73

Partial-Volume Effect on Ischemic Tissue-Fate Delineation Using Quantitative Perfusion and Diffusion  

E-print Network

. In stroke imaging, PVE could hamper proper delineation of normal, ischemic, and at-risk tissues by blurring and Diffusion Imaging on a Rat Stroke Model Hongxia Ren,1,4 Qiang Shen,1,4 Juergen Bardutzky,2,3 Marc Fisher,2 and Timothy Q. Duong1,2* Partial-volume effects (PVE) in stroke imaging could hinder proper delineation

Duong, Timothy Q.

74

An MR image-guided, voxel-based partial volume correction method for PET images  

PubMed Central

Purpose: Partial volume effect in positron emission tomography (PET) can cause incorrect quantification of radiopharmaceutical uptake in functional imaging. A PET partial volume correction method is presented to attenuate partial volume blurring and to yield voxel-based corrected PET images. Methods: By modeling partial volume effect as a convolution of point spread function of the PET scanner, the reconstructed PET images are corrected by iterative deconvolution with an edge-preserving smoothness constraint. The constraint is constructed to restore discontinuities extracted from coregistered MR images but maintains the smoothness in radioactivity distribution. The correction is implemented in a Bayesian deconvolution framework and is solved by a conjugate gradient method. The performance of the method was compared with the geometric transfer matrix (GTM) method on a simulated dataset. The method was evaluated on synthesized brain FDG–PET data and phantom MRI–PET experiments. Results: The true PET activity of objects with a size of greater than the full-width at half maximum of the point spread function has been effectively restored in the simulated data. The partial volume correction method is quantitatively comparable to the GTM method. For synthesized FDG–PET with true activity 0 ?ci/cc for cerebrospinal fluid (CSF), 228 ?ci/cc for white matter (WM), and 621 ?ci/cc for gray matter (GM), the method has improved the radioactivity quantification from 186?±?16 ?ci/cc to 30?±?7 ?ci/cc in CSF, 317?±?15 ?ci/cc to 236?±?10 ?ci/cc for WM, 438?±?4 ?ci/cc to 592?±?5 ?ci/cc for GM. Both visual and quantitative assessments show improvement of partial volume correction in the synthesized and phantom experiments. Conclusions: The partial volume correction method improves the quantification of PET images. The method is comparable to the GTM method but does not need MR image segmentation or prior tracer distribution information. The voxel-based method can be particularly useful for combined PET/MRI studies. PMID:22225287

Wang, Hesheng; Fei, Baowei

2012-01-01

75

A method for model-free partial volume correction in oncological PET  

PubMed Central

Background As is well known, limited spatial resolution leads to partial volume effects (PVE) and consequently to limited signal recovery. Determination of the mean activity concentration of a target structure is thus compromised even at target sizes much larger than the reconstructed spatial resolution. This leads to serious size-dependent underestimates of true signal intensity in hot spot imaging. For quantitative PET in general and in the context of therapy assessment in particular it is, therefore, mandatory to perform an adequate partial volume correction (PVC). The goal of our work was to develop and to validate a model-free PVC algorithm for hot spot imaging. Methods The algorithm proceeds in two automated steps. Step 1: estimation of the actual object boundary with a threshold based method and determination of the total activity A measured within the enclosed volume V. Step 2: determination of the activity fraction B, which is measured outside the object due to the partial volume effect (spill-out). The PVE corrected mean value is then given by Cmean = (A+B)/V. For validation simulated tumours were used which were derived from real patient data (liver metastases of a colorectal carcinoma and head and neck cancer, respectively). The simulated tumours have characteristics (regarding tumour shape, contrast, noise, etc.) which are very similar to those of the underlying patient data, but the boundaries and tracer accumulation are exactly known. The PVE corrected mean values of 37 simulated tumours were determined and compared with the true mean values. Results For the investigated simulated data the proposed approach yields PVE corrected mean values which agree very well with the true values (mean deviation (± s.d.): (?0.8±2.5)%). Conclusions The described method enables accurate quantitative partial volume correction in oncological hot spot imaging. PMID:22531468

2012-01-01

76

Measurement of Radiotracer Concentration in Brain Gray Matter Using Positron Emission Tomography: MRI-Based Correction for Partial Volume Effects  

Microsoft Academic Search

Summary: Accuracy in in vivo quantitation of brain function with positron emission tomography (PET) has often been limited by partial volume effects. This limitation becomes prominent in studies of aging and degenerative brain diseases where partial volume effects vary with different degrees of atrophy. The present study describes how the actual gray matter (GM) tracer concentration can be estimated using

Hans W. Muller-Gartner; Jonathan M. Links; Jerry L. Prince; R. Nick Bryan; Elliot McVeigh; Jeffrey P. Leal; Christos Davatzikos; J. James Frost

1992-01-01

77

Gender differences in partial-volume corrected brain perfusion using brain MRI in healthy children  

Microsoft Academic Search

To investigate gender differences in brain perfusion, this study utilized pulsed arterial spin-labeling magnetic resonance imaging (MRI) in a large number of healthy children. Data on structural and perfusion MRI in the brain were collected from 202 healthy children aged 5–18years. Gender differences in brain perfusion using partial volume correction (PVC), which was calculated by dividing the normalized perfusion MRI

Yasuyuki Taki; Hiroshi Hashizume; Yuko Sassa; Hikaru Takeuchi; Kai Wu; Michiko Asano; Kohei Asano; Hiroshi Fukuda; Ryuta Kawashima

2011-01-01

78

High-Quality Hardware-Based Ray-Casting Volume Rendering Using Partial Pre-Integration  

Microsoft Academic Search

In this paper, we address the problem of the interac- tive volume rendering of unstructured meshes and propose a new hardware-based ray-casting algorithm using partial pre-integration. The proposed algorithm makes use of mod- ern programmable graphics card and achieves rendering rates competitive with full pre-integration approaches (up to 2M tet\\/sec). This algorithm allows the interactive mod- ication of the transfer

Rodrigo Espinha; Waldemar Celes Filho

2005-01-01

79

Investigation of partial volume correction methods for brain FDG PET studies  

SciTech Connect

The use of positron emission tomography (PET) in quantitative fluorodeoxyglucose (FDG) studies of aging and dementia has been limited by partial volume effects. A general method for correction of partial volume effects (PVE) in PET involves the following common procedures; segmentation of MRI brain images into gray matter (GM), white matter (WM), cerebral spinal fluid (CSF), and muscle (MS) components; MRI PET registration; and generation of simulated PET images. Afterward, two different approaches can be taken. The first approach derives first a pixel-by-pixel correction map as the ratio of the measured image to the simulated image [with realistic full-width at half-maximum (FWHM)]. The correction map was applied to the MRI segmentation image. Regions of interest (ROI`s) can then be applied to give results free of partial volume effects. The second approach uses the ROI values of the simulated ``pure`` image (with negligible FWHM) and those of the simulated and the measured PET images to correct for the PVE effect. By varying the ratio of radiotracer concentrations for different tissue components, the in-plane FWHM`s of a three-dimensional point spread function, and the ROI size, the authors evaluated the performance of these two approaches in terms of their accuracy and sensitivity to different simulation configurations. The results showed that both approaches are more robust than the approach developed by Muller-Gartner et al., and the second approach is more accurate and more robust than the first. In conclusion, the authors recommend that the second approach should be used on FDG PET images to correct for partial volume effects and to determine whether an apparent change in GM radiotracer concentration is truly due to metabolic changes.

Yang, J.; Huang, S.C.; Mega, M.; Toga, A.W.; Small, G.W.; Phelps, M.E. [Univ. of California, Los Angeles, CA (United States)] [Univ. of California, Los Angeles, CA (United States); Lin, K.P. [Chung Yuan Christian Univ., Chung-Li (China). Dept. of Electrical Engineering] [Chung Yuan Christian Univ., Chung-Li (China). Dept. of Electrical Engineering

1996-12-01

80

Density Contrast Sedimentation Velocity for the Determination of Protein Partial-Specific Volumes  

PubMed Central

The partial-specific volume of proteins is an important thermodynamic parameter required for the interpretation of data in several biophysical disciplines. Building on recent advances in the use of density variation sedimentation velocity analytical ultracentrifugation for the determination of macromolecular partial-specific volumes, we have explored a direct global modeling approach describing the sedimentation boundaries in different solvents with a joint differential sedimentation coefficient distribution. This takes full advantage of the influence of different macromolecular buoyancy on both the spread and the velocity of the sedimentation boundary. It should lend itself well to the study of interacting macromolecules and/or heterogeneous samples in microgram quantities. Model applications to three protein samples studied in either H2O, or isotopically enriched H218O mixtures, indicate that partial-specific volumes can be determined with a statistical precision of better than 0.5%, provided signal/noise ratios of 50–100 can be achieved in the measurement of the macromolecular sedimentation velocity profiles. The approach is implemented in the global modeling software SEDPHAT. PMID:22028836

Brown, Patrick H.; Balbo, Andrea; Zhao, Huaying; Ebel, Christine; Schuck, Peter

2011-01-01

81

Target Volume Delineation for Partial Breast Radiotherapy Planning: Clinical Characteristics Associated with Low Interobserver Concordance  

SciTech Connect

Purpose: To examine variability in target volume delineation for partial breast radiotherapy planning and evaluate characteristics associated with low interobserver concordance. Methods and Materials: Thirty patients who underwent planning CT for adjuvant breast radiotherapy formed the study cohort. Using a standardized scale to score seroma clarity and consensus contouring guidelines, three radiation oncologists independently graded seroma clarity and delineated seroma volumes for each case. Seroma geometric center coordinates, maximum diameters in three axes, and volumes were recorded. Conformity index (CI), the ratio of overlapping volume and encompassing delineated volume, was calculated for each case. Cases with CI {<=}0.50 were analyzed to identify features associated with low concordance. Results: The median time from surgery to CT was 42.5 days. For geometric center coordinates, variations from the mean were 0.5-1.1 mm and standard deviations (SDs) were 0.5-1.8 mm. For maximum seroma dimensions, variations from the mean and SDs were predominantly <5 mm, with the largest SDs observed in the medial-lateral axis. The mean CI was 0.61 (range, 0.27-0.84). Five cases had CI {<=}0.50. Conformity index was significantly associated with seroma clarity (p < 0.001) and seroma volume (p < 0.002). Features associated with reduced concordance included tissue stranding from the surgical cavity, proximity to muscle, dense breast parenchyma, and benign calcifications that may be mistaken for surgical clips. Conclusion: Variability in seroma contouring occurred in three dimensions, with the largest variations in the medial-lateral axis. Awareness of clinical features associated with reduced concordance may be applied toward training staff and refining contouring guidelines for partial breast radiotherapy trials.

Petersen, Ross P. [Radiation Therapy Program, British Columbia Cancer Agency, Vancouver Island Centre and University of British Columbia, Victoria, BC (Canada); Truong, Pauline T. [Radiation Therapy Program, British Columbia Cancer Agency, Vancouver Island Centre and University of British Columbia, Victoria, BC (Canada)], E-mail: ptruong@bccancer.bc.ca; Kader, Hosam A.; Berthelet, Eric; Lee, Junella C. [Radiation Therapy Program, British Columbia Cancer Agency, Vancouver Island Centre and University of British Columbia, Victoria, BC (Canada); Hilts, Michelle L. [Radiation Therapy Program, British Columbia Cancer Agency, Vancouver Island Centre and University of Victoria, Victoria, BC (Canada); Kader, Adam S. [Radiation Therapy Program, British Columbia Cancer Agency, Vancouver Island Centre and University of British Columbia, Victoria, BC (Canada); Beckham, Wayne A. [Radiation Therapy Program, British Columbia Cancer Agency, Vancouver Island Centre and University of Victoria, Victoria, BC (Canada); Olivotto, Ivo A. [Radiation Therapy Program, British Columbia Cancer Agency, Vancouver Island Centre and University of British Columbia, Victoria, BC (Canada)

2007-09-01

82

The molar volume of cubic garnets in the system SiO2-Al2O3-TiO2-Fe2O3-Cr2O3-FeO-MnO-MgO-CaO-Na2O  

NASA Astrophysics Data System (ADS)

Garnet is a critical phase that controls major and trace element partitioning at pressures above ~3 GPa during partial melting of the Earth's upper mantle. A molar volume model is calibrated for cubic garnets (space group Ia3d) in the oxide system listed in the title. This model and a recent calibration of spinel molar volume (Hamecher et al., in press, CMP) will be used in calibration of thermodynamic activity-composition models of garnet and pyroxene solid solutions. The activity and molar volume models will be incorporated into the next generation MELTS (Ghiorso & Sack, 1995, CMP) model, xMELTS. A new garnet volume model calibrated with recent in situ high-P, T diffraction data is crucial for accurately modeling key mineralogical transitions in the mantle, e.g., the spinel-garnet transition and the mantle transition zone. Above 5 GPa a majorite component is an essential part of any thermodynamic model of mantle garnets, which to be useful must accurately predict garnet stability with respect to spinel, pyroxene, perovskites, and melt. Our model system contains nine independent end members: Ca3Al2Si3O12, Mg3Al2Si3O12, Fe2+3Al2Si3O12, Mg3Cr2Si3O12, Mg3Fe3+2Si3O12, Mn3Al2Si3O12, Na2(MgSi2)Si3O12, Mg3(TiMg)Si3O12, and cubic majorite component Mg3(MgSi)Si3O12. An inclusive set of end-member components is formed by linear combinations of these explicit end members. Approximately 950 published X-ray diffraction experiments performed on garnets at ambient and in situ high-P, T conditions are used to calibrate end-member equations of state and an excess volume model for this system. Optimal values of the bulk modulus and its pressure derivative are obtained by analyzing published compression and/or ultrasonic data for the end members for which such studies exist; for other end members, density functional theory results are used. For any cubic garnet in this chemical system, the model molar volume is obtained by adding excess volume terms to a linear combination of the nine independent end-member volumes. In the first step of our least squares fitting procedure we calculate volumes of the explicit end members as a function of P and T using the high-T Vinet equation of state. We allow standard state volumes and coefficients of thermal expansion to vary for those independent end members where pure compositional data exist, either for the phase itself or for an appropriate dependent end member. For each dependent end member for which there are data, we calculate the volume of reaction for formation of the phase from the independent end members, ?V. We then fit the binary and mixed composition data, using the singular value analysis method of Lawson & Hanson (1974) to ensure that the calibrated combinations of excess parameters obey the nine ?V constraints from the first step. A key plausibility check on the model results from comparing the predicted T-dependence of the bulk modulus to high-T ultrasonic results that were not used in the calibration. The calculated pressure of the spinel-garnet transition using the new volume models is compared to that obtained with the previous models. The implications our model has for the density of the lithospheric mantle are explored.

Hamecher, E. A.; Antoshechkina, P. M.; Ghiorso, M. S.; Asimow, P. D.

2012-12-01

83

Partial volume correction of brain perfusion estimates using the inherent signal data of time-resolved arterial spin labeling.  

PubMed

Quantitative perfusion MRI based on arterial spin labeling (ASL) is hampered by partial volume effects (PVEs), arising due to voxel signal cross-contamination between different compartments. To address this issue, several partial volume correction (PVC) methods have been presented. Most previous methods rely on segmentation of a high-resolution T1 -weighted morphological image volume that is coregistered to the low-resolution ASL data, making the result sensitive to errors in the segmentation and coregistration. In this work, we present a methodology for partial volume estimation and correction, using only low-resolution ASL data acquired with the QUASAR sequence. The methodology consists of a T1 -based segmentation method, with no spatial priors, and a modified PVC method based on linear regression. The presented approach thus avoids prior assumptions about the spatial distribution of brain compartments, while also avoiding coregistration between different image volumes. Simulations based on a digital phantom as well as in vivo measurements in 10 volunteers were used to assess the performance of the proposed segmentation approach. The simulation results indicated that QUASAR data can be used for robust partial volume estimation, and this was confirmed by the in vivo experiments. The proposed PVC method yielded probable perfusion maps, comparable to a reference method based on segmentation of a high-resolution morphological scan. Corrected gray matter (GM) perfusion was 47% higher than uncorrected values, suggesting a significant amount of PVEs in the data. Whereas the reference method failed to completely eliminate the dependence of perfusion estimates on the volume fraction, the novel approach produced GM perfusion values independent of GM volume fraction. The intra-subject coefficient of variation of corrected perfusion values was lowest for the proposed PVC method. As shown in this work, low-resolution partial volume estimation in connection with ASL perfusion estimation is feasible, and provides a promising tool for decoupling perfusion and tissue volume. PMID:25066601

Ahlgren, André; Wirestam, Ronnie; Petersen, Esben Thade; Ståhlberg, Freddy; Knutsson, Linda

2014-09-01

84

Densities, Excess Molar Volumes, Ultrasonic Speeds, and Isentropic Compressibilities of Hexan-1-ol with 1,2-Dichloroethane, 1,2-Dibromoethane, and 1,1,2,2-Tetrachloroethene at (293.15 and 298.15) K  

NASA Astrophysics Data System (ADS)

Densities, ?, and ultrasonic speeds, u, of binary mixtures of hexan-1-ol with 1,2-dichloroethane, 1,2-dibromoethane, and 1,1,2,2-tetrachloroethene have been measured over the entire range of composition at (293.15 and 298.15) K and atmospheric pressure. From these data, the excess molar volumes, V E, deviations of ultrasonic speed, u D, from the ultrasonic speed of an ideal mixture, excess molar isentropic compressibilities, {kappa_{S,m}^E}, intermolecular free lengths, L f, mean molecular radii, r, and thermal expansion coefficients, ?, have been calculated. The experimental ultrasonic speeds have been analyzed in terms of Nomoto's, Van Dael's ideal mixture, and Junjie relations; Jacobson's free length and Schaaffs' collision factor theories; and thermoacoustical parameters.

Bhatia, Subhash C.; Bhatia, Rachna; Dubey, Gyan P.

2010-12-01

85

A detailed analysis of partial molecular volumes in DPPC/cholesterol binary bilayers.  

PubMed

We examined the volumetric behavior of the dipalmitoylphosphatidylcholine (DPPC)/cholesterol binary bilayer system with high accuracy and more cholesterol concentrations to reveal the detailed molecular states in the liquid-disordered (Ld) phase, the liquid-ordered (Lo) phase and the gel phase. We measured the average specific volume of the binary bilayer at several temperatures by the neutral flotation method and calculated the average volume per molecule to estimate the partial molecular volumes of DPPC and cholesterol in each phase. As a result, we found that the region with intermediate cholesterol concentrations showed a more complicated behavior than expected from simple coexistence of Ld and Lo domains. We also measured fluorescence decay of trans-parinaric acid (tPA) added into the binary bilayer with more cholesterol concentrations to get further insight into the cholesterol-induced formation of the Lo phase. On the basis of these results we discuss the molecular interaction between DPPC and cholesterol molecule in the Lo phase and the manner of Ld/Lo phase coexistence. PMID:25151597

Miyoshi, Tsubasa; Lönnfors, Max; Peter Slotte, J; Kato, Satoru

2014-12-01

86

Effects of concentration, temperature and solvent composition on density and apparent molar volume of the binary mixtures of cationic-anionic surfactants in methanol-water mixed solvent media.  

PubMed

The accurate measurements on density of the binary mixtures of cetyltrimethylammonium bromide and sodium dodecyl sulphate in pure water and in methanol(1) + water (2) mixed solvent media containing (0.10, 0.20, and 0.30) volume fractions of methanol at 308.15, 318.15, and 323.15 K are reported. The concentrations are varied from (0.03 to 0.12) mol.l(-1) of sodium dodecyl sulphate in presence of ~ 5.0×10(-4) mol.l(-1) cetyltrimethylammonium bromide. The results showed almost increase in the densities with increasing surfactant mixture concentration, also the densities are found to decrease with increasing temperature over the entire concentration range, investigated in a given mixed solvent medium and these values are found to decrease with increasing methanol content in the solvent composition. The concentration dependence of the apparent molar volumes appear to be negligible over the entire concentration range, investigated in a given mixed solvent medium and the apparent molar volumes increase with increasing temperature and are found to decrease with increasing methanol content in the solvent composition. PMID:23961383

Bhattarai, Ajaya; Chatterjee, Sujeet Kumar; Niraula, Tulasi Prasad

2013-01-01

87

Excess molar volumes of (octane + benzene, or toluene, or 1,3-xylene, or 1,3,5-trimethylbenzene) at temperatures between (298.15 and 328.15) K  

Microsoft Academic Search

The densities of (octane+benzene, or toluene, or 1,3-xylene, or 1,3,5-trimethylbenzene) were measured at temperatures (298.15, 308.15, 318.15, and 328.15)K by means of a vibrating-tube densimeter. The excess molar volumes VmE calculated from the density data provide the temperature dependence of VmE in the temperature range of (298 to 328)K. The VmE results were correlated using the fourth-order Redlich–Kister equation, with

L. Morávková; J. Linek

2008-01-01

88

Excess molar volumes of (benzene + isopropylbenzene, or 1,3,5-trimethylbenzene, or 1,2,4-trimethylbenzene) at temperatures between 298.15 K and 328.15 K  

Microsoft Academic Search

The densities of (benzene+isopropylbenzene, or 1,2,4-trimethylbenzene, or 1,3,5-trimethylbenzene) were measured at temperatures (298.15, 308.15, 318.15, and 328.15) K by means of a vibrating-tube densimeter. The excess molar volumes VmE calculated from the density data provide the temperature dependence of VmE in the temperature range of (298 to 328) K. The VmE results were correlated using the fourth-order Redlich–Kister equation, with

L. Morávková; J. Linek

2003-01-01

89

Intraoperative molar pregnancy crisis.  

PubMed

Molar pregnancy is a gestation in which the ovum is transformed into a fleshy tumor mass or mole. Of all gynecologic tumors, it is one of the most feared. It is characterized by first trimester bleeding, hyperemesis, and toxemia and can be diagnosed using pelvic ultrasound. Suction currettage is the treatment of choice for molar pregnancy when a patient desires to have more children; however, hysterectomy may be necessary. Abdominal hysterectomy reduces the risk of malignant sequelae. Complications associated with molar pregnancy usually are a result of suction curettage and include pulmonary insufficiency syndrome, choriocarcinoma, hyperthyroidism, theca lutein cysts, and disseminated intravascular coagulation. The perioperative nurse can be instrumental in assessing, planning, organizing, and directing intervention for potential complications associated with the management of a molar pregnancy crisis. The perioperative nurse is encouraged to review all aspects of molar pregnancy to understand the ramifications of the surgical procedures. PMID:7944318

Robinson, B J

1994-08-01

90

Partial-Volume Correction in PET: Validation of an Iterative Postreconstruction Method with Phantom and Patient Data  

Microsoft Academic Search

Partial-volume errors (PVEs) in PET can cause incorrect estima- tion of radiopharmaceutical uptake in small tumors. An iterative postreconstruction method was evaluated that corrects for PVEs without a priori knowledge of tumor size or background. Methods:Volumes of interest (VOIs) were drawn on uncorrected PET images. PVE-corrected images were produced using an it- erative 3-dimensional deconvolution algorithm and a local point

Boon-Keng Teo; Youngho Seo; Stephen L. Bacharach; Jorge A. Carrasquillo; Steven K. Libutti; Himanshu Shukla; Bruce H. Hasegawa; Randall A. Hawkins; Benjamin L. Franc

2007-01-01

91

Differences in Effective Target Volume Between Various Techniques of Accelerated Partial Breast Irradiation  

SciTech Connect

Purpose: Different cavity expansions are used to define the clinical target volume (CTV) for accelerated partial breast irradiation (APBI) delivered via balloon brachytherapy (1 cm) vs. three-dimensional conformal radiotherapy (3D-CRT) (1.5 cm). Previous studies have argued that the CTVs generated by these different margins are effectively equivalent. In this study, we use deformable registration to assess the effective CTV treated by balloon brachytherapy on clinically representative 3D-CRT planning images. Methods and Materials: Ten patients previously treated with the MammoSite were studied. Each patient had two computed tomography (CT) scans, one acquired before and one after balloon implantation. In-house deformable registration software was used to deform the MammoSite CTV onto the balloonless CT set. The deformed CTV was validated using anatomical landmarks common to both CT scans. Results: The effective CTV treated by the MammoSite was on average 7% {+-} 10% larger and 38% {+-} 4% smaller than 3D-CRT CTVs created using uniform expansions of 1 and 1.5 cm, respectively. The average effective CTV margin was 1.0 cm, the same as the actual MammoSite CTV margin. However, the effective CTV margin was nonuniform and could range from 5 to 15 mm in any given direction. Effective margins <1 cm were attributable to poor cavity-balloon conformance. Balloon size relative to the cavity did not significantly correlate with the effective margin. Conclusion: In this study, the 1.0-cm MammoSite CTV margin treated an effective volume that was significantly smaller than the 3D-CRT CTV based on a 1.5-cm margin.

Shaitelman, Simona F.; Vicini, Frank A.; Grills, Inga S.; Martinez, Alvaro A.; Yan Di [Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI (United States); Kim, Leonard H., E-mail: lkim@beaumonthospitals.com [Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI (United States)

2012-01-01

92

Conditional partial volume correction for emission tomography: A wavelet-based hidden Markov model and multi-resolution approach  

Microsoft Academic Search

The spatial resolution in emission tomography induces partial volume effects, leading to under-estimation of the real uptake and activity spillover. They can be corrected using either region of interest or voxel based approaches. We developed a voxel wise correction, based on the wavelet transform of two co-registered images in order to insert high resolution details of the anatomical image into

Adrien Le Pogam; Mathieu Hatt; Nicolas Boussion; Denis Guilloteau; Jean-louis Baulieu; Caroline Prunier; Federico Turkheimer; Dimitris Visvikis

2008-01-01

93

Pseudo-rigid Body Modeling of IPMC for a Partially Compliant Four-bar Mechanism for Work Volume Generation  

Microsoft Academic Search

Conventional four-bar crank rocker mechanisms made of rigid links can generate only one path, at the rocker tip, for one revolution of the crank. However, if the rocker length can be actively changed then its tip can generate a work volume. This study describes an application of ionic polymer metal composite (IPMC) as a partially compliant rocker in a four-bar

Dibakar Bandopadhya; Bishakh Bhattacharya; Ashish Dutta

2009-01-01

94

Spinal Cord Tolerance to Single-Fraction Partial-Volume Irradiation: A Swine Model  

SciTech Connect

Purpose: To determine the spinal cord tolerance to single-fraction, partial-volume irradiation in swine. Methods and Materials: A 5-cm-long cervical segment was irradiated in 38-47-week-old Yucatan minipigs using a dedicated, image-guided radiosurgery linear accelerator. The radiation was delivered to a cylindrical volume approximately 5 cm in length and 2 cm in diameter that was positioned lateral to the cervical spinal cord, resulting in a dose distribution with the 90%, 50%, and 10% isodose lines traversing the ipsilateral, central, and contralateral spinal cord, respectively. The dose was prescribed to the 90% isodose line. A total of 26 pigs were stratified into eight dose groups of 12-47 Gy. The mean maximum spinal cord dose was 16.9 {+-} 0.1, 18.9 {+-} 0.1, 21.0 {+-} 0.1, 23.0 {+-} 0.2, and 25.3 {+-} 0.3 Gy in the 16-, 18-, 20-, 22-, and 24-Gy dose groups, respectively. The mean percentage of spinal cord volumes receiving {>=}10 Gy for the same groups were 43% {+-} 3%, 48% {+-} 4%, 51% {+-} 2%, 57% {+-} 2%, and 59% {+-} 4%. The study endpoint was motor neurologic deficit determined by a change in gait during a 1-year follow-up period. Results: A steep dose-response curve was observed with a median effective dose for the maximum dose point of 20.0 Gy (95% confidence interval, 18.3-21.7). Excellent agreement was observed between the occurrence of neurologic change and the presence of histologic change. All the minipigs with motor deficits showed some degree of demyelination and focal white matter necrosis on the irradiated side, with relative sparing of the gray matter. The histologic findings were unremarkable in the minipigs with normal neurologic status. Conclusions: Our results have indicated that for a dose distribution with a steep lateral gradient, the pigs had a lower median effective dose for paralysis than has been observed in rats and more closely resembles that for rats, mice, and guinea pigs receiving uniform spinal cord irradiation.

Medin, Paul M., E-mail: Paul.medin@utsouthwestern.ed [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX (United States); Foster, Ryan D. [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX (United States); Kogel, Albert J. van der [Department of Radiation Oncology, Radboud University Medical Center Nijmegen, Nijmegen (Netherlands); Sayre, James W. [Department of Biostatistics, University of California, Los Angeles, School of Medicine, Los Angeles, CA (United States); Department of Radiology, University of California, Los Angeles, School of Medicine, Los Angeles, CA (United States); McBride, William H. [Department of Radiation Oncology, University of California, Los Angeles, School of Medicine, Los Angeles, CA (United States); Solberg, Timothy D. [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX (United States)

2011-01-01

95

Isotropic non-white matter partial volume effects in constrained spherical deconvolution.  

PubMed

Diffusion-weighted (DW) magnetic resonance imaging (MRI) is a non-invasive imaging method, which can be used to investigate neural tracts in the white matter (WM) of the brain. Significant partial volume effects (PVEs) are present in the DW signal due to relatively large voxel sizes. These PVEs can be caused by both non-WM tissue, such as gray matter (GM) and cerebrospinal fluid (CSF), and by multiple non-parallel WM fiber populations. High angular resolution diffusion imaging (HARDI) methods have been developed to correctly characterize complex WM fiber configurations, but to date, many of the HARDI methods do not account for non-WM PVEs. In this work, we investigated the isotropic PVEs caused by non-WM tissue in WM voxels on fiber orientations extracted with constrained spherical deconvolution (CSD). Experiments were performed on simulated and real DW-MRI data. In particular, simulations were performed to demonstrate the effects of varying the diffusion weightings, signal-to-noise ratios (SNRs), fiber configurations, and tissue fractions. Our results show that the presence of non-WM tissue signal causes a decrease in the precision of the detected fiber orientations and an increase in the detection of false peaks in CSD. We estimated 35-50% of WM voxels to be affected by non-WM PVEs. For HARDI sequences, which typically have a relatively high degree of diffusion weighting, these adverse effects are most pronounced in voxels with GM PVEs. The non-WM PVEs become severe with 50% GM volume for maximum spherical harmonics orders of 8 and below, and already with 25% GM volume for higher orders. In addition, a low diffusion weighting or SNR increases the effects. The non-WM PVEs may cause problems in connectomics, where reliable fiber tracking at the WM-GM interface is especially important. We suggest acquiring data with high diffusion-weighting 2500-3000 s/mm(2), reasonable SNR (~30) and using lower SH orders in GM contaminated regions to minimize the non-WM PVEs in CSD. PMID:24734018

Roine, Timo; Jeurissen, Ben; Perrone, Daniele; Aelterman, Jan; Leemans, Alexander; Philips, Wilfried; Sijbers, Jan

2014-01-01

96

Evaluation of partial volume effect correction methods for brain positron emission tomography: Quantification and reproducibility  

PubMed Central

Quantitative accuracy of positron emission tomography (PET) is decreased by the partial volume effect (PVE). The PVE correction (PVC) methods proposed by Alfano et al., Rousset et al., Müller-Gärtner et al. and Meltzer et al. were evaluated in the present study to obtain guidelines for selecting among them. For accuracy evaluation, the Hoffman brain phantom was scanned with three PETs of differing spatial resolution in order to measure the effect of PVC on radioactivity distribution. Test-retest data consisting of duplicate dynamic emission recordings of the dopamine D2-receptor ligand [11C] raclopride obtained in eight healthy control subjects were used to test the correction effect in different regions of interest. The PVC method proposed by Alfano et al. gave the best quantification accuracy in the brain gray matter region. When the effect of PVC on reliability was tested with human data, the method of Meltzer et al. proved to be the most reliable. The method by Alfano et al. may be better for group comparison studies and the method by Meltzer et al. for intra-subject drug-effect studies. PMID:21157530

Harri, Merisaari; Mika, Teras; Jussi, Hirvonen; Nevalainen, Olli S.; Jarmo, Hietala

2007-01-01

97

Factors affecting the accuracy of volume-oscillometric blood pressure measurement during partial pressurization of the wrist.  

PubMed

We compared the volume-oscillometric responses of the airbag pressure sensor and the contact force sensor across and along the radial artery on the wrist during partial pressurization by an airbag. Because of the anatomic structure and non-uniform pressurization pressure distribution, elongated and shifted oscillometric pressure waveform envelope variations are observed. For the contact force sensors directly above the radial artery, S-shaped pressurization curves can be seen possibly due to temporal softening of the radial artery stiffness at near zero transmural pressure. These differences in the shape of oscillometric envelope as well as pressurization curve may be the leading factors for inaccuracies of volume-oscillometric blood pressure measurement by partial pressurization method using an airbag. PMID:19963727

Kim, Jong Pal; Kim, Youn Ho; Bae, Sangkon; Kim, Seok Chan; Shin, Kunsoo

2009-01-01

98

Prevalence of missing and impacted third molars in adults aged 25 years and above  

PubMed Central

Purpose The purpose of this study was to determine the prevalence of missing and impacted third molars in people aged 25 years and above. Materials and Methods The study sample of 3,799 patients was chosen randomly from patients who visited Pusan National University Dental Hospital and had panoramic radiographs taken. The data collected included presence and impaction state, angulation, and depth of impaction of third molars, and radiographically detected lesions of third molars and adjacent second molars. Results A greater percentage of men than women retained at least one third molar. The incidence of third molars decreased with increasing age. The incidence of partially impacted third molars greatly declined after the age of 30. Vertically impacted maxillary third molars and horizontally impacted mandibular third molars were most frequent in all age groups. Among the maxillary third molars, those impacted below the cervical line of the second molar were most frequent in all age groups, and among the mandibular third molars, deeply impacted third molars were most frequent in those aged over 40. Dental caries was the most common radiographic lesion of the third molars. Mesioangularly impacted third molars showed radiographic lesions in 13 (9.5%) adjacent maxillary second molars and 117 (27.4%) mandibular second molars. Conclusion The number of remaining third molars decreased and the percentage of Class C depth increased with age. Caries was the most frequent lesion in third molars. Partially impacted mesioangular third molars showed a high incidence of caries or periodontal bone loss of the adjacent second molar. Regular oral examination will be essential to keep asymptomatic third molars in good health. PMID:24380060

Jung, Yun-Hoa

2013-01-01

99

JOURNAL OF PETROLOGY VOLUME 39 NUMBER 6 PAGES 10911115 1998 Calculation of Peridotite Partial Melting from  

E-print Network

leads to exaggerated calculated Na con- centrations for near-solidus partial melts of peridotite the solidus, where the composition of the liquid is changing rapidly, but that once the composition of the liquid ceases to changeis the prediction by MELTS that at 1 GPa, near-solidus partial melts of fertile

Asimow, Paul D.

100

Anatomical structural network analysis of human brain using partial correlations of gray matter volumes  

Microsoft Academic Search

Structural connectivity in human brain has been studied by modeling the statistical dependence between features of cortical regions, such as gray matter thickness. Statistical correlations between gray matter thickness have been mainly used as a metric to study this dependence. In this paper, we propose the use of partial correlations instead of Pearson correlation for inferring the brain structural connectivity

Anand A. Joshi; Shantanu H. Joshi; Ivo D. Dinov; David W. Shattuck; Richard M. Leahy; Arthur W. Toga

2010-01-01

101

JOURNAL OF PETROLOGY VOLUME 40 NUMBER 2 PAGES 297313 1999 Calculation of Peridotite Partial Melting from  

E-print Network

Melting from Thermodynamic Models of Minerals and Melts. II. Isobaric Variations in Melts near the Solidus depend on whether compositionallythat near-solidus enrichments in SiO2 become less pronounced of the enriched sourcespressure. Calculated near-solidus solid­liquid partitioning of TiO2 can yield partial melts

Asimow, Paul D.

102

VAPOR PRESSURES, LIQUID MOLAR VOLUMES, VAPOR NON- IDEALITIES, AND CRITICAL PROPERTIES OF SOME FLUORINATED ETHERS: CF3OCF2OCF3, CF3OCF2 CF2H, c- CF2CF2CF2O, CF3OCF2H, AND CF3OCH3; AND OF CCl3F AND CF2ClH  

EPA Science Inventory

Vapor pressures, compressibilities, expansivities, and molar volumes of the liquid phase have been measured between room temperature and the critical temperature for a series of fluorinated ethers: CF3OCF2OCF3, CF3OCF2CF2H, c-CF2CF2CF2O, CF3OCF2H, and CF3OCH3. Vapor-phase non-ide...

103

Comparing a volume based template approach and ultrasound guided freehand approach in multicatheter interstitial accelerated partial breast irradiation  

PubMed Central

Purpose Currently, there are two described methods of catheter insertion for women undergoing multicatheter interstitial accelerated partial breast irradiation (APBI). These are a volume based template approach (template) and a non-template ultrasound guidance freehand approach (non-template). We aim to compare dosimetric endpoints between the template and non-template approach. Material and methods Twenty patients, who received adjuvant multicatheter interstitial APBI between August 2008 to March 2010 formed the study cohort. Dosimetric planning was based on the RTOG 04-13 protocol. For standardization, the planning target volume evaluation (PTV-Eval) and organs at risk were contoured with the assistance of the attending surgeon. Dosimetric endpoints include D90 of the PTV-Eval, Dose Homogeneity Index (DHI), V200, maximum skin dose (MSD), and maximum chest wall dose (MCD). A median of 18 catheters was used per patient. The dose prescribed was 34 Gy in 10 fractions BID over 5 days. Results The average breast volume was 846 cm3 (526-1384) for the entire cohort and there was no difference between the two groups (p = 0.6). Insertion time was significantly longer for the non-template approach (mean 150 minutes) compared to the template approach (mean: 90 minutes) (p = 0.02). The planning time was also significantly longer for the non-template approach (mean: 240 minutes) compared to the template approach (mean: 150 minutes) (p < 0.01). The template approach yielded a higher D90 (mean: 95%) compared to the non-template approach (mean: 92%) (p < 0.01). There were no differences in DHI (p = 0.14), V200 (p = 0.21), MSD (p = 0.7), and MCD (p = 0.8). Conclusions Compared to the non-template approach, the template approach offered significant shorter insertion and planning times with significantly improved dosimetric PTV-Eval coverage without significantly compromising organs at risk dosimetrically. PMID:25097558

Koh, Vicky Y.; Buhari, Shaik A.; Tan, Poh Wee; Tan, Yun Inn; Leong, Yuh Fun; Earnest, Arul

2014-01-01

104

Partial volume correction of the microPET blood input function using ensemble learning independent component analysis  

NASA Astrophysics Data System (ADS)

Medical images usually suffer from a partial volume effect (PVE), which may degrade the accuracy of any quantitative information extracted from the images. Our aim was to recreate accurate radioactivity concentration and time-activity curves (TACs) by microPET R4 quantification using ensemble learning independent component analysis (EL-ICA). We designed a digital cardiac phantom for this simulation and in order to evaluate the ability of EL-ICA to correct the PVE, the simulated images were convoluted using a Gaussian function (FWHM = 1-4 mm). The robustness of the proposed method towards noise was investigated by adding statistical noise (SNR = 2-16). During further evaluation, another set of cardiac phantoms were generated from the reconstructed images, and Poisson noise at different levels was added to the sinogram. In real experiments, four rat microPET images and a number of arterial blood samples were obtained; these were used to estimate the metabolic rate of FDG (MRFDG). Input functions estimated using the FastICA method were used for comparison. The results showed that EL-ICA could correct PVE in both the simulated and real cases. After correcting for the PVE, the errors for MRFDG, when estimated by the EL-ICA method, were smaller than those when TACs were directly derived from the PET images and when the FastICA approach was used.

Su, Kuan-Hao; Lee, Jih-Shian; Li, Jia-Hung; Yang, Yu-Wen; Liu, Ren-Shian; Chen, Jyh-Cheng

2009-03-01

105

A study of shape-dependent partial volume correction in pet imaging using ellipsoidal phantoms fabricated via rapid prototyping  

NASA Astrophysics Data System (ADS)

Positron emission tomography (PET) with 2-[18F]fluoro-2-deoxy-D-glucose (FDG) is being increasingly recognized as an important tool for quantitative assessment of tumor response because of its ability to capture functional information about the tumor's metabolism. However, despite many advances in PET technology, measurements of tumor radiopharmaceutical uptake in PET are still challenged by issues of accuracy and consistency, thereby compromising the use of PET as a surrogate endpoint in clinical trials. One limiting component of the overall uncertainty in PET is the relatively poor spatial resolution of the images which directly affects the accuracy of the tumor radioactivity measurements. These spatial resolution effects, colloquially known as the partial volume effect (PVE), are a function of the characteristics of the scanner as well as the tumor being imaged. Previous efforts have shown that the PVE depends strongly on the tumor volume and the background-to-tumor activity concentration ratio. The PVE is also suspected to be a function of tumor shape, although to date no systematic study of this effect has been performed. This dissertation seeks to help fill the gap in the current knowledge about the shape-dependence of the PVE by attempting to quantify, through both theoretical calculation and experimental measurement, the magnitude of the shape effect for ellipsoidal tumors. An experimental investigation of the tumor shape effect necessarily requires tumor phantoms of multiple shapes. Hence, a prerequisite for this research was the design and fabrication of hollow tumor phantoms which could be filled uniformly with radioactivity and imaged on a PET scanner. The phantom fabrication was achieved with the aid of stereolithography and included prolate ellipsoids of various axis ratios. The primary experimental method involved filling the tumor phantoms with solutions of 18F whose activity concentrations were known and traceable to primary radioactivity standards held by the National Institute of Standards and Technology (NIST). The tumor phantoms were then placed inside a Jaszczak cylinder (representing the human body) and imaged on a PET scanner located at NIST. This experimental approach allowed for the testing of: (1) The relative difference between tumors phantoms of different shapes, but same volume; (2) The overall accuracy of the PET measurements in terms of a ground truth reference value. Theoretical calculations of the tumor shape effect were also performed by mathematically convolving the phantom shapes with a 3D Gaussian point-spread function, and the results of the calculations were compared with the experimental data. The data show that the shape effect in PET tumor imaging can be as large as 15% for ellipsoid phantoms with axis ratios of 2:1, volume of 1.15 cm 3, and tumor-to-background activity concentration ratio of 9:1. This is explained by a greater loss of counts along the minor axis direction in the ellipsoid tumors compared to that of spheres of the same volume. The results of this PhD research confirm the existence of a tumor shape effect PET imaging. However, except in the case of ellipsoids with major-to-minor axis ratio greater than 2:1, a correction for the effect using recovery coefficients is expected to be challenging because its magnitude is comparable to the repeatability of the PET measurements.

Mille, Matthew M.

106

Molarization of Mandibular Second Premolar  

PubMed Central

ABSTRACT Macrodontia (megadontia, megalodontia, mac rodontism) is a rare shape anomaly that has been used to describe dental gigantism. Mandibular second premolars show an elevated variability of crown morphology, as are its eruptive potential and final position in the dental arch. To date, only eight cases of isolated macrodontia of second premolars have been reported in the literature. This case report presents clinical and radiographic findings of unusual and rare case of isolated unilateral molarization of left mandibular second premolar. How to cite this article: Mangla N, Khinda VIS, Kallar S, Brar GS. Molarization of Mandibular Second Premolar. Int J Clin Pediatr Dent 2014;7(2):137-139. PMID:25356014

Singh Khinda, Vineet Inder; Kallar, Shiminder; Singh Brar, Gurlal

2014-01-01

107

METHODS DEVELOPMENT FOR ASSESSING AIR POLLUTION CONTROL BENEFITS. VOLUME IV. STUDIES ON PARTIAL EQUILIBRIUM APPROACHES TO VALUATION OF ENVIRONMENTAL AMENITIES  

EPA Science Inventory

The research presented in this volume of a five volume study of the economic benefits of air pollution control explores various facets of the two central project objectives that have not been given adequate attention in the previous volumes. The valuations developed in these prev...

108

Molar Incisor Hypomineralization, Prevalence, and Etiology  

PubMed Central

Aim. To evaluate the prevalence and possible etiological factors associated with molar incisor hypomineralization (MIH) among a group of children in Jeddah, Saudi Arabia. Methods. A group of 8-12-year-old children were recruited (n = 267) from the Pediatric Dental Clinics at the Faculty of Dentistry, King Abdulaziz University. Children had at least one first permanent molar (FPM), erupted or partially erupted. Demographic information, children's medical history, and pregnancy-related data were obtained. The crowns of the FPM and permanent incisors were examined for demarcated opacities, posteruptive breakdown (PEB), atypical restorations, and extracted FPMs. Children were considered to have MIH if one or more FPM with or without involvement of incisors met the diagnostic criteria. Results. MIH showed a prevalence of 8.6%. Demarcated opacities were the most common form. Maxillary central incisors were more affected than mandibular (P = 0.01). The condition was more prevalent in children with history of illnesses during the first four years of life including tonsillitis (P = 0.001), adenoiditis (P = 0.001), asthma (P = 0.001), fever (P = 0.014), and antibiotics intake (P = 0.001). Conclusions. The prevalence of MIH is significantly associated with childhood illnesses during the first four years of life including asthma, adenoid infections, tonsillitis, fever, and antibiotics intake. PMID:24949012

Allazzam, Sulaiman Mohammed; Alaki, Sumer Madani; El Meligy, Omar Abdel Sadek

2014-01-01

109

A comparison of conventional surfactant treatment and partial liquid ventilation on the lung volume of injured ventilated small lungs.  

PubMed

As an alternative to surfactant therapy (ST), partial liquid ventilation (PLV) with perfluorocarbons (PFC) has been considered as a treatment for acute lung injury (ALI) in newborns. The instilled PFC is much heavier than the instilled surfactant and the aim of this study was to investigate whether PLV, compared to ST, increases the end-expiratory volume of the lung (VL). Fifteen newborn piglets (age <12 h, mean weight 678 g) underwent saline lung lavage to achieve a surfactant depletion. Thereafter animals were randomized to PLV (n = 8), receiving PFC PF5080 (3M, Germany) at 30 mL kg(-1), and ST (n = 7) receiving 120 mg Curosurf®. Blood gases, hemodynamics and static compliance were measured initially (baseline), immediately after ALI, and after 240 min mechanical ventilation with either technique. Subsequently all piglets were killed; the lungs were removed in toto and frozen in liquid N2. After freeze-drying the lungs were cut into lung cubes (LCs) with edge lengths of 0.7 cm, to calculate VL. All LCs were weighed and the density of the dried lung tissue was calculated. No statistically significant differences between treatment groups PLV and ST (means ± SD) were noted in body weight (676 ± 16 g versus 679 ± 17 g; P = 0.974) or lung dry weight (1.64 ± 0.29 g versus 1.79 ± 0.48 g; P = 0.48). Oxygenation index and ventilatory efficacy index did not differ significantly between both groups at any time. VL (34.28 ± 6.13 mL versus 26.22 ± 8.1 mL; P < 0.05) and the density of the dried lung tissue (48.07 ± 5.02 mg mL(-1) versus 69.07 ± 5.30 mg mL(-1); P < 0.001), however, differed significantly between the PLV and ST groups. A 4 h PLV treatment of injured ventilated small lungs increased VL by 30% and decreased lung density by 31% compared to ST treatment, indicating greater lung distension after PLV compared to ST. PMID:23893018

Proquitté, Hans; Hartenstein, Sebastian; Koelsch, Uwe; Wauer, Roland R; Rüdiger, Mario; Schmalisch, Gerd

2013-08-01

110

Statistical genetics of molar cusp patterning in pedigreed baboons: implications for primate dental development and evolution.  

PubMed

Gene expression and knock-out studies provide considerable information about the genetic mechanisms required for tooth organogenesis. Quantitative genetic studies of normal phenotypic variation are complementary to these developmental studies and may help elucidate the genes and mechanisms that contribute to the normal population-level phenotypic variation upon which selection acts. Here we present the first quantitative genetic analysis of molar cusp positioning in mammals. We analyzed quantitative measures of molar cusp position in a captive pedigreed baboon breeding colony housed at the Southwest National Primate Research Center in San Antonio, Texas. Our results reveal complete pleiotropy between antimeric pairs of traits--i.e., they are influenced by the same gene or suite of genes. Mandibular morphological homologues in the molar series also exhibit complete pleiotropy. In contrast, morphological homologues in maxillary molar series appear to be influenced by partial, incomplete pleiotropic effects. Variation in the mandibular mesial and distal molar loph orientation on the same molar crown is estimated to be genetically independent, whereas the maxillary molar mesial and distal loph orientation is estimated to have partially overlapping genetic affects. The differences between the maxillary and mandibular molar patterning, and the degree of genetic independence found between lophs on the same molar crown, may be indicative of previously unrecognized levels of modularity in the primate dentition. PMID:15211686

Hlusko, Leslea J; Maas, Mary-Louise; Mahaney, Michael C

2004-05-15

111

Geometric morphometric 3D shape analysis and covariation of human mandibular and maxillary first molars.  

PubMed

Dental casts of 160 Greek subjects (80 males, 80 females) were scanned by a structured-light scanner. The upper and lower right first molar occlusal surface 3D meshes were processed using geometric morphometric methods. A total of 265 and 274 curve and surface sliding semilandmarks were placed on the upper and lower molar surfaces, respectively. Principal component analysis and partial least square analysis were performed to assess shape parameters. Molars tended to vary between an elongated and a more square form. The first two principal components (PCs), comprising almost 1/3 of molar shape variation, were related to mesiodistal-buccolingual ratios and relative cusp position. Distal cusps displayed the greatest shape variability. Molars of males were larger than those of females (2.8 and 3.2% for upper and lower molars respectively), but no shape dimorphism was observed. Upper and lower molar sizes were significantly correlated (r(2) = 0.689). Allometry was observed for both teeth. Larger lower molars were associated with shorter cusps, expansion of the distal cusp, and constriction of the mesial cusps (predicted variance 3.25%). Upper molars displayed weaker allometry (predicted variance 1.59%). Upper and lower molar shape covariation proved significant (RV = 17.26%, P < 0.0001). The main parameter of molar covariation in partial least square axis 1, contributing to 30% of total covariation, was cusp height, in contrast to the primary variability traits exhibited by PC1 and PC2. The aim of this study was to evaluate shape variation and covariation, including allometry and sexual dimorphism, of maxillary and mandibular first permanent molar occlusal surfaces. PMID:24009105

Polychronis, Georgios; Christou, Panagiotis; Mavragani, Maria; Halazonetis, Demetrios J

2013-10-01

112

Characterisation of partial volume effect and region-based correction in small animal positron emission tomography (PET) of the rat brain.  

PubMed

Accurate quantification of PET imaging data is required for a useful interpretation of the measured radioactive tracer concentrations. The partial volume effect (PVE) describes signal dilution and mixing due to spatial resolution and sampling limitations, which introduces bias in quantitative results. In the present study we investigated the magnitude of PVE for volumes of interest (VOIs) in the rat brain and the effect of positron range. In simulated (11)C-raclopride studies we examined the influence of PVE on time activity curves in striatal and cerebellar VOIs and binding potential estimation. The performance of partial volume correction (PVC) was studied using the region-based geometric transfer matrix (GTM) method including the question of whether a spatially variant point spread function (PSF) is necessary for PVC of a rat brain close to the centre of the field of view. Furthermore, we determined the effect of spillover from activity outside the brain. The results confirmed that PVE is significant in rat brain PET and showed that positron range is an important factor that needs to be included in the PSF. There was considerable bias in time activity curves for the simulated (11)C-raclopride studies and significant underestimation of binding potential even for very small centred VOIs. Good activity recovery was achieved with the GTM PVC using a spatially invariant simulated PSF when no activity was present outside the brain. PVC using a simple Gaussian fit point spread function was not sufficiently accurate. Spillover from regions outside the brain had a significant impact on measured activity concentrations and reduced the accuracy of PVC with the GTM method using rat brain regions alone, except for the smallest VOI size but at the cost of increased noise. Voxel-based partial volume correction methods which inherently compensate for spillover from outside the brain might be a more suitable choice. PMID:22387126

Lehnert, Wencke; Gregoire, Marie-Claude; Reilhac, Anthonin; Meikle, Steven R

2012-05-01

113

Molar versus as a paradigm clash.  

PubMed Central

The molar view of behavior arose in response to the demonstrated inadequacy of explanations based on contiguity. Although Dinsmoor's (2001) modifications to two-factor theory render it irrefutable, a more basic criticism arises when we see that the molar and molecular views differ paradigmatically. The molar view has proven more productive. PMID:11453623

Baum, W M

2001-01-01

114

When Is CT-Based Postoperative Seroma Most Useful to Plan Partial Breast Radiotherapy? Evaluation of Clinical Factors Affecting Seroma Volume and Clarity  

SciTech Connect

Purpose: To evaluate the effect of the time from surgery and other clinical factors on seroma volume and clarity and establish the optimal time to use the computed tomography (CT)-based seroma to plan partial breast irradiation (PBI). Methods and Materials: A total of 205 women with early-stage breast cancer underwent planning CT after breast-conserving surgery. One radiation oncologist contoured the seroma volume and scored the seroma clarity, using a standardized Seroma Clarity Score scale, from 0 (not detectable) to 5 (clearest). Univariate and multivariate analyses were performed to evaluate the associations between the seroma characteristics and the interval from surgery and other clinical factors. Results: The mean interval from surgery to CT was 84 days (standard deviation 59). During postoperative Weeks 3-8, the mean seroma volume decreased from 47 to 30 cm{sup 3}, stabilized during Weeks 9-14 (mean 21) and was involuted beyond 14 weeks (mean 9 cm{sup 3}). The mean seroma clarity score was 3.4 at Weeks 3-8, 2.5 at Weeks 9-14, and 1.6 after 14 weeks. The seroma clarity was greater in patients aged {>=}70 years. The seroma volume and clarity correlated significantly with the volume of excised breast tissue but not with the maximal tumor diameter, surgical re-excision, or chemotherapy use. Conclusion: The optimal time to obtain the planning CT scan for PBI is within 8 weeks after surgery. During Weeks 9-14, the seroma might remain adequately defined in some patients; however, after 14 weeks, alternate strategies are needed to identify the PBI target. The lack of correlation between the seroma volume and tumor size suggests that the CT-based seroma should not be the sole guide for PBI target volume definition.

Kader, Hosam A. [Radiation Therapy Program, British Columbia Cancer Agency, Vancouver Island Centre, Victoria, BC (Canada); University of British Columbia, Victoria, BC (Canada)], E-mail: hkader@bccancer.bc.ca; Truong, Pauline T. [Radiation Therapy Program, British Columbia Cancer Agency, Vancouver Island Centre, Victoria, BC (Canada); University of British Columbia, Victoria, BC (Canada); Pai, Rohit [University of Victoria, Victoria, BC (Canada); Panades, Miguel [Radiation Therapy Program, British Columbia Cancer Agency, Vancouver Island Centre, Victoria, BC (Canada); Jones, Stuart; Ansbacher, Will [Radiation Therapy Program, British Columbia Cancer Agency, Vancouver Island Centre, Victoria, BC (Canada); University of Victoria, Victoria, BC (Canada); Olivotto, Ivo A. [Radiation Therapy Program, British Columbia Cancer Agency, Vancouver Island Centre, Victoria, BC (Canada); University of British Columbia, Victoria, BC (Canada)

2008-11-15

115

Measurement of D2 dopamine receptor-specific carbon-11-YM-09151-2 binding in the canine brain by PET: Importance of partial volume correction  

SciTech Connect

Carbon-11-YM-09151-2 binds highly selectively to D2 dopamine receptors in the brain. Using this ligand, D2 dopamine receptor density (Bmax) and affinity (Kd) in canine striatum were measured. After administering various doses of the ligand in nine experiments, regional uptake was followed by repeated PET scanning for up to 80 min. D2 dopamine receptor specific binding at equilibrium was defined as striatal minus occipital activity after partial volume correction. Bmax and Kd were estimated by Scatchard analysis to be 40.3 pmole/ml of tissue and 22.9 nM, respectively. When a low mass dose of the ligand was administered, the bound-to-free ligand ratio in the striatum at equilibrium was consistent with the Bmax/Kd value obtained from the Scatchard analysis. The present study demonstrates the importance of partial volume correction and the Bmax/Kd measurement in a single PET study with carbon-11-YM-09151-2.

Hatazawa, J.; Hatano, K.; Ishiwata, K.; Itoh, M.; Ido, T.; Kawashima, K.; Meguro, K.; Watanuki, S.; Seo, S. (Tohoku Univ., Sendai (Japan))

1991-04-01

116

[On eruption of mandibular third molar after extraction of mandibular first or second molar].  

PubMed

In the orthodontic practice, the first or second molars are extracted by reason of a necessity based on the treatment planning. In these cases, it is desirable that the third molar would be taken part in the masticatory function. This study was made to investigate the natural movement of the erupting third molars after the extraction of the first or second molar on the serial lateral cephalometric radiographs and orthopantomographs. Subjects were divided into three groups. The first is the group which the mandibular second molars were extracted. The second is the group which the first molars were extracted bringing about the successful eruption of the third molars. The third is the group which the first molars were extracted with resultant in the failure of the third molar eruption. In all cases, the orthodontic forces were not applied to the third molars. The results were as follows: 1. In the first group, all third molars were successfully erupted and a lot of the spaces after the extraction of second molars were utilized for the eruption of third molars. 2. In the second group, all third molars were successfully erupted and a lot of the spaces after the extraction of first molars were utilized for the mesial movement of the second molars. 3. In the third group, there were various patterns of the impaction of the third molars. It was suggested that the eruption of the third molar was related to the space distal to the second molar but it was not related to the anterio-posterior length of the mandibular body significantly. PMID:2133887

Yamabe, K; Kouguchi, M; Watanabe, Y; Yamauchi, K

1990-08-01

117

Impact of Increasing Margin Around the Lumpectomy Cavity to Define the Planning Target Volume for 3D Conformal External Beam Accelerated Partial Breast Irradiation  

SciTech Connect

The purpose of this study was to evaluate the dose to normal tissues as a function of increasing margins around the lumpectomy cavity in accelerated partial breast irradiation (APBI) using 3D-conformal radiotherapy (3DCRT). Eight patients with Stage 0-I breast cancer underwent treatment planning for 3DCRT APBI. The clinical target volume (CTV) was defined as a 15-mm expansion around the cavity limited by the chest wall and skin. Three planning target volumes (PTV1, PTV2, PTV3) were generated for each patient using a 0, 5-, and 10-mm expansion around the CTV, for a total margin of 15, 20, and 25 mm. Three treatment plans were generated for every patient using the 3 PTVs, and dose-volume analysis was performed for each plan. For each 5-mm increase in margin, the mean PTV:total breast volume ratio increased 10% and the relative increase in the mean ipsilateral breast dose was 15%. The mean volume of ipsilateral breast tissue receiving 75%, 50%, and 25% of the prescribed dose increased 6% to 7% for every 5 mm increase in PTV margin. Compared to lesions located in the upper outer quadrant, plans for medially located tumors revealed higher mean ipsilateral breast doses and 20% to 22% more ipsilateral breast tissue encompassed by the 25% IDL. The use of 3DCRT for APBI delivers higher doses to normal breast tissue as the PTV increases around the lumpectomy cavity. Efforts should be made to minimize the overall PTV when this technique is used. Ongoing studies will be necessary to determine the clinical relevance of these findings.

Cox, Brett W. [Department of Radiation Oncology, Stanford University, Stanford, CA (United States); Horst, Kathleen C. [Department of Radiation Oncology, Stanford University, Stanford, CA (United States)], E-mail: kateh@stanford.edu; Thornton, Sherri [Department of Radiation Oncology, Stanford University, Stanford, CA (United States); Dirbas, Frederick M. [Department of Surgery, Stanford University, Stanford, CA (United States)

2007-01-01

118

Reducing the influence of the partial volume effect on SPECT activity quantitation with 3D modelling of spatial resolution in iterative reconstruction  

NASA Astrophysics Data System (ADS)

Quantitative parameters such as the maximum and total counts in a volume are influenced by the partial volume effect. The magnitude of this effect varies with the non-stationary and anisotropic spatial resolution in SPECT slices. The objective of this investigation was to determine whether iterative reconstruction which includes modelling of the three-dimensional (3D) spatial resolution of SPECT imaging can reduce the impact of the partial volume effect on the quantitation of activity compared with filtered backprojection (FBP) techniques which include low-pass, and linear restoration filtering using the frequency distance relationship (FDR). The iterative reconstruction algorithms investigated were maximum-likelihood expectation-maximization (MLEM), MLEM with ordered subset acceleration (ML-OS), and MLEM with acceleration by the rescaled-block-iterative technique (ML-RBI). The SIMIND Monte Carlo code was used to simulate small hot spherical objects in an elliptical cylinder with and without uniform background activity as imaged by a low-energy ultra-high-resolution (LEUHR) collimator. Centre count ratios (CCRs) and total count ratios (TCRs) were determined as the observed counts over true counts. CCRs were unstable while TCRs had a bias of for all iterative techniques. The variance in the TCRs for ML-OS and ML-RBI was clearly elevated over that of MLEM, with ML-RBI having the smaller elevation. TCRs obtained with FDR-Wiener filtering had a larger bias than any of the iterative reconstruction methods but near stationarity is also reached. Butterworth filtered results varied by 9.7% from the centre to the edge. The addition of background has an influence on the convergence rate and noise properties of iterative techniques.

Pretorius, P. H.; King, M. A.; Pan, T.-S.; de Vries, D. J.; Glick, S. J.; Byrne, C. L.

1998-02-01

119

Complications following removal of impacted third molars: the role of the experience of the surgeon.  

PubMed

The incidence of complications associated with the removal of impacted third molars in a group of 500 patients treated by oral surgery faculty were compared with the incidence of complications in 208 patients treated during the same period by residents of oral and maxillofacial surgery. The results show that complications were more numerous after the removal of third molars classified as partial bony or complete bony impactions, and that less-experienced surgeons had a significantly higher incidence of such complications. PMID:3464711

Sisk, A L; Hammer, W B; Shelton, D W; Joy, E D

1986-11-01

120

Minimizing the partial volume effect using the respiratory signal timing in the art of capturing images of the pet CT  

NASA Astrophysics Data System (ADS)

This work describes the development of an algorithm capable of filtering a signal captured by a breath of the NTC thermistor and then synchronizes this signal to a pulse generator. The measurement is essential for biomedical signals to obtain physiological data for diagnostic or research purposes. The information was obtained from an analysis of signals available in the database of phisionet. The greater relevance of this work is the possibility of contributing to medical research to identify the cancer cells present in small volumes of organs located in the thoracic region of patients undergoing clinical evaluation.

Souza Goulão, Welder; dos Santos Werneck Rodrigues, Araken

2012-12-01

121

Prevalence and Pattern of Third Molar Impaction  

PubMed Central

Objectives: The aim of this retrospective study was to investigate the prevalence and pattern of third molar impaction in patients between 19–26 years old attending Sultan Qaboos University Hospital (SQUH) in Muscat, Oman. Methods: The study reviewed 1,000 orthopantomograms (OPGs) of patients attending the Oral Health Department of SQUH between October 2010 and April 2011. Patients were evaluated to determine the prevalence of third molar impaction, angulation, level of eruption and associated pathological conditions. Results: Of the study population, 543 (54.3%) OPGs showed at least one impacted third molar. The total number of impacted molars was 1,128. The most common number of impacted third molars was two (41%). The most common angulation of impaction in the mandible was the mesioangular (35%) and the most common level of impaction in the mandible was level A. Of the 388 bilateral occurrences of impacted third molars, 377 were in the mandible. There was no significant difference in the frequency of impaction between the right and left sides of both jaws. Pathological conditions associated with impacted lower third molars were found in 18%, of which 14% were associated with a radiographic radiolucency of more than 2.5 mm, and 4% of impacted lower third molars were associated with dental caries. Conclusion: This study found that more than half of Omani adult patients ranging in age from 19–26 years had at least one impacted third molar. PMID:25097776

Al-Anqudi, Samira M.; Al-Sudairy, Salim; Al-Hosni, Ahmed; Al-Maniri, Abdullah

2014-01-01

122

Molar Malocclusions in Pine Voles (Microtus pinetorum)  

PubMed Central

Here we describe 5 cases of molar malocclusions in adult pine voles (Microtus pinetorum) used for behavioral endocrinology studies. This species belongs to the subfamily Microtinae, which possess aradicular hypsodont molars. The abnormal molars identified caused apparent difficulty in mastication, resulting in poor body condition necessitating euthanasia. Postmortem examination of the oral cavity revealed grossly elongated mandibular and maxillary molars with abnormal wear at occlusal surfaces. This colony health problem was addressed successfully by adding autoclaved hardwood sticks to each cage as an enrichment tool. PMID:19653952

Harvey, Stephen B; Alworth, Leanne C; Blas-Machado, Uriel

2009-01-01

123

PET imaging of thin objects: measuring the effects of positron range and partial-volume averaging in the leag of Nicotiana Tabacum  

SciTech Connect

PET imaging in plants is receiving increased interest as a new strategy to measure plant responses to environmental stimuli and as a tool for phenotyping genetically engineered plants. PET imaging in plants, however, poses new challenges. In particular, the leaves of most plants are so thin that a large fraction of positrons emitted from PET isotopes ({sup 18}F, {sup 11}C, {sup 13}N) escape while even state-of-the-art PET cameras have significant partial-volume errors for such thin objects. Although these limitations are acknowledged by researchers, little data have been published on them. Here we measured the magnitude and distribution of escaping positrons from the leaf of Nicotiana tabacum for the radionuclides {sup 18}F, {sup 11}C and {sup 13}N using a commercial small-animal PET scanner. Imaging results were compared to radionuclide concentrations measured from dissection and counting and to a Monte Carlo simulation using GATE (Geant4 Application for Tomographic Emission). Simulated and experimentally determined escape fractions were consistent. The fractions of positrons (mean {+-} S.D.) escaping the leaf parenchyma were measured to be 59 {+-} 1.1%, 64 {+-} 4.4% and 67 {+-} 1.9% for {sup 18}F, {sup 11}C and {sup 13}N, respectively. Escape fractions were lower in thicker leaf areas like the midrib. Partial-volume averaging underestimated activity concentrations in the leaf blade by a factor of 10 to 15. The foregoing effects combine to yield PET images whose contrast does not reflect the actual activity concentrations. These errors can be largely corrected by integrating activity along the PET axis perpendicular to the leaf surface, including detection of escaped positrons, and calculating concentration using a measured leaf thickness.

Alexoff, D.L.; Alexoff, D.L.; Dewey, S.L.; Vaska, P.; Krishnamoorthy, S.; Ferrieri, R.; Schueller, M.; Schlyer, D.; Fowler, J.S.

2011-03-01

124

Mandibular molar root morphology in Neanderthals and Late Pleistocene and recent Homo sapiens.  

PubMed

Neanderthals have a distinctive suite of dental features, including large anterior crown and root dimensions and molars with enlarged pulp cavities. Yet, there is little known about variation in molar root morphology in Neanderthals and other recent and fossil members of Homo. Here, we provide the first comprehensive metric analysis of permanent mandibular molar root morphology in Middle and Late Pleistocene Homo neanderthalensis, and Late Pleistocene (Aterian) and recent Homo sapiens. We specifically address the question of whether root form can be used to distinguish between these groups and assess whether any variation in root form can be related to differences in tooth function. We apply a microtomographic imaging approach to visualise and quantify the external and internal dental morphologies of both isolated molars and molars embedded in the mandible (n=127). Univariate and multivariate analyses reveal both similarities (root length and pulp volume) and differences (occurrence of pyramidal roots and dental tissue volume proportion) in molar root morphology among penecontemporaneous Neanderthals and Aterian H. sapiens. In contrast, the molars of recent H. sapiens are markedly smaller than both Pleistocene H. sapiens and Neanderthals, but share with the former the dentine volume reduction and a smaller root-to-crown volume compared with Neanderthals. Furthermore, we found the first molar to have the largest average root surface area in recent H. sapiens and Neanderthals, although in the latter the difference between M(1) and M(2) is small. In contrast, Aterian H. sapiens root surface areas peak at M(2). Since root surface area is linked to masticatory function, this suggests a distinct occlusal loading regime in Neanderthals compared with both recent and Pleistocene H. sapiens. PMID:20719359

Kupczik, Kornelius; Hublin, Jean-Jacques

2010-11-01

125

Immature primary molar in the newborn  

Microsoft Academic Search

A clinical report of an erupted immature primary molar in a newborn is presented. The occurrence of a natal or neonatal molar can be considered a rare event since the majority of cases described are incisors. Clinical appearance, location, histological and radiographical examinations were used to establish the identity oF the lesion, The literature related to natal and neonatal teeth

Stephen K Brandt; Steven D. Shapiro; Paul E. Kittle

1983-01-01

126

Expressly Fabricated Molar Tube Bases: Enhanced Adhesion  

PubMed Central

Clinicians, Orthodontists and their patients’ parents often expect the best results in the shortest time span possible. Orthodontic bonding of molar tubes has been an acceptable risk in a modern era of refined biomaterials and instrumentation. Although many orthodontists still prefer banding to bonding, it is the failure rate of the tubes on molars which accounts to an impedance in molar bonding. One of the reasons for molar attachment failures is attributed to improper adaptation of the buccal tube base with or without increased thickness of composite. Merits of banding the second molars especially when these are the terminal teeth for anchorage have been overemphasized in the literature. The present article presents a simple and relatively less time consuming technique of preparing molar tubes to be bonded on tooth surfaces which may be quite difficult to isolate especially for bonding, for example, mandibular second molars. The increased surface area of the composite scaffold helps not only in enhanced bond strength but also serves to reduce the incidence of plaque accumulation given the dexterity of invitro preparation. The removal of the occlusal part of the molar tube scaffold helps in prevention of open / raised bite tendencies. The present innovation, therefore, is not merely serendipity but a structured technique to overcome a common dilemma for the clinical orthodontist. The present dictum of banding being superior to molar tube bonding may prove to be futile with trendsetting molar attachments. It is also an established fact that bonding proves to be a lesser expensive modality when compared to banding procedures. PMID:25121070

Phull, Tarun Singh; Rana, Tarun; Kumar, Varun

2014-01-01

127

The Effect of Dose-Volume Parameters and Interfraction Interval on Cosmetic Outcome and Toxicity After 3-Dimensional Conformal Accelerated Partial Breast Irradiation  

SciTech Connect

Purpose: To evaluate dose-volume parameters and the interfraction interval (IFI) as they relate to cosmetic outcome and normal tissue effects of 3-dimensional conformal radiation therapy (3D-CRT) for accelerated partial breast irradiation (APBI). Methods and Materials: Eighty patients were treated by the use of 3D-CRT to deliver APBI at our institutions from 2003-2010 in strict accordance with the specified dose-volume constraints outlined in the National Surgical Adjuvant Breast and Bowel Project B39/Radiation Therapy Oncology Group 0413 (NSABP-B39/RTOG 0413) protocol. The prescribed dose was 38.5 Gy in 10 fractions delivered twice daily. Patients underwent follow-up with assessment for recurrence, late toxicity, and overall cosmetic outcome. Tests for association between toxicity endpoints and dosimetric parameters were performed with the chi-square test. Univariate logistic regression was used to evaluate the association of interfraction interval (IFI) with these outcomes. Results: At a median follow-up time of 32 months, grade 2-4 and grade 3-4 subcutaneous fibrosis occurred in 31% and 7.5% of patients, respectively. Subcutaneous fibrosis improved in 5 patients (6%) with extended follow-up. Fat necrosis developed in 11% of women, and cosmetic outcome was fair/poor in 19%. The relative volume of breast tissue receiving 5%, 20%, 50%, 80%, and 100% (V5-V100) of the prescribed dose was associated with risk of subcutaneous fibrosis, and the volume receiving 50%, 80%, and 100% (V50-V100) was associated with fair/poor cosmesis. The mean IFI was 6.9 hours, and the minimum IFI was 6.2 hours. The mean and minimum IFI values were not significantly associated with late toxicity. Conclusions: The incidence of moderate to severe late toxicity, particularly subcutaneous fibrosis and fat necrosis and resulting fair/poor cosmesis, remains high with continued follow-up. These toxicity endpoints are associated with several dose-volume parameters. Minimum and mean IFI values were not associated with late toxicity.

Leonard, Kara Lynne, E-mail: karalynne.kerr@gmail.com [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts (United States); Hepel, Jaroslaw T. [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts (United States) [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts (United States); Department of Radiation Oncology, Rhode Island Hospital, Warren Alpert School of Medicine of Brown University, Providence, Rhode Island (United States); Hiatt, Jessica R. [Department of Radiation Oncology, Rhode Island Hospital, Warren Alpert School of Medicine of Brown University, Providence, Rhode Island (United States)] [Department of Radiation Oncology, Rhode Island Hospital, Warren Alpert School of Medicine of Brown University, Providence, Rhode Island (United States); Dipetrillo, Thomas A. [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts (United States) [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts (United States); Department of Radiation Oncology, Rhode Island Hospital, Warren Alpert School of Medicine of Brown University, Providence, Rhode Island (United States); Price, Lori Lyn [Department of Biostatistics Research Center, Institute of Clinical Research and Health Policy Studies, Tufts Medical Center, Boston, Massachusetts (United States)] [Department of Biostatistics Research Center, Institute of Clinical Research and Health Policy Studies, Tufts Medical Center, Boston, Massachusetts (United States); Wazer, David E. [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts (United States) [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts (United States); Department of Radiation Oncology, Rhode Island Hospital, Warren Alpert School of Medicine of Brown University, Providence, Rhode Island (United States)

2013-03-01

128

Antibiotics in third molar surgery.  

PubMed

The aim of this survey was to assess the knowledge and practice of Swiss dentists focusing on the use of antibiotics in prophylactic surgical removal of lower wisdom teeth. A postal survey was conducted among all 3288 dentists who are members of the Swiss Dental Society (SSO) representing nearly all dentists in Switzerland. The questionnaire consisted of 13 questions with mostly multiple-choice answers. Demographic profile, surgical experience, the use of antibiotics, and wound management, i.e. wound closure and the use of mouth rinse were assessed. A response rate of 55% was obtained. Most Swiss dentists perform surgical extractions in their practices. Of all dentists, 18.6% used antibiotics routinely, but a large variation was found comparing the three linguistic regions of Switzerland with the highest prescription rate of 48% in the French-speaking south-west of Switzerland. Fifty-two percent of dentists prescribed amoxicillin in a dose of 750 mg. Most often three daily doses were prescribed (47%). A postoperative regime was prescribed by 54.4% of dentists. French language (p=0.003), graduation from the university of Geneva (p=0.007), foreign diplomas (p<0.001), and dentists with diplomas awarded from 2001-2006 (p=0.004) showed a highly significant correlation with the use of antibiotics. In Switzerland, prophylactic antibiotics are used in third molar surgery. Antibiotic prescription however largely depends on geographical situation and dentist profiles. The assessment of antibiotic use in private practices is important in the light of growing evidence that antibiotic overuse may lead to development of multiresistant bacterial strains. In a second part results regarding wound management and mouth rinse will be presented. PMID:24671748

Vlcek, Daniel; Razavi, Amir; Kuttenberger, Johannes J

2014-01-01

129

Unilateral Molar Distalization: A Nonextraction Therapy  

PubMed Central

In the recent years, nonextraction treatment approaches and noncompliance therapies have become more popular in the correction of space discrepancies. One of the conventional approaches for space gaining in the arches without patient compliance is done by using certain extra oral appliances or intraoral appliance. The greatest advantage of certain appliances like fixed functional and molar distalization appliances is that they minimize the dependence on patient cooperation. Molar distalization appliances like pendulum appliance which distalizes the molar rapidly without the need of head gear can be used in patients as a unilateral space gaining procedure due to buccal segment crowding. PMID:23320203

Prasad, M. Bhanu; Sreevalli, S.

2012-01-01

130

Apparent and partial molal volumes in mixed salt solutions. I. The ternary systems LiCl-LiNO3-H2O, NaCl-NaNO3-H2O and KCl-KNO3-H2O  

Microsoft Academic Search

The densities of aqueous mixtures of LiCl-LiNO3, NaCl-NaNO3, and KCl-KNO3 were determined at 25 °C at constant chloride-nitrate molality ratios. The mean apparent molal volumes were calculated and found to obey the limiting law modified by additional terms in ionic strength. The partial molal volumes for the electrolytes in each mixture were calculated and the conditions under which Young and

J. Padova; I. Lewkowicz

1976-01-01

131

Molars and incisors: show your microarray IDs  

PubMed Central

Background One of the key questions in developmental biology is how, from a relatively small number of conserved signaling pathways, is it possible to generate organs displaying a wide range of shapes, tissue organization, and function. The dentition and its distinct specific tooth types represent a valuable system to address the issues of differential molecular signatures. To identify such signatures, we performed a comparative transcriptomic analysis of developing murine lower incisors, mandibular molars and maxillary molars at the developmental cap stage (E14.5). Results 231 genes were identified as being differentially expressed between mandibular incisors and molars, with a fold change higher than 2 and a false discovery rate lower than 0.1, whereas only 96 genes were discovered as being differentially expressed between mandibular and maxillary molars. Numerous genes belonging to specific signaling pathways (the Hedgehog, Notch, Wnt, FGF, TGF?/BMP, and retinoic acid pathways), and/or to the homeobox gene superfamily, were also uncovered when a less stringent fold change threshold was used. Differential expressions for 10 out of 12 (mandibular incisors versus molars) and 9 out of 10 selected genes were confirmed by quantitative reverse transcription-PCR (qRT-PCR). A bioinformatics tool (Ingenuity Pathway Analysis) used to analyze biological functions and pathways on the group of incisor versus molar differentially expressed genes revealed that 143 genes belonged to 9 networks with intermolecular connections. Networks with the highest significance scores were centered on the TNF/NF?B complex and the ERK1/2 kinases. Two networks ERK1/2 kinases and tretinoin were involved in differential molar morphogenesis. Conclusion These data allowed us to build several regulatory networks that may distinguish incisor versus molar identity, and may be useful for further investigations of these tooth-specific ontogenetic programs. These programs may be dysregulated in transgenic animal models and related human diseases leading to dental anomalies. PMID:23531410

2013-01-01

132

A Prospective Pathologic Study to Define the Clinical Target Volume for Partial Breast Radiation Therapy in Women With Early Breast Cancer  

SciTech Connect

Purpose: To determine an appropriate clinical target volume for partial breast radiation therapy (PBRT) based on the spatial distribution of residual invasive and in situ carcinoma after wide local excision (WLE) for early breast cancer or ductal carcinoma in situ (DCIS). Methods and Materials: We performed a prospective pathologic study of women potentially eligible for PBRT who had re-excision and/or completion mastectomy after WLE for early breast cancer or DCIS. A pathologic assessment protocol was used to determine the maximum radial extension (MRE) of residual carcinoma from the margin of the initial surgical cavity. Women were stratified by the closest initial radial margin width: negative (>1 mm), close (>0 mm and {<=}1 mm), or involved. Results: The study population was composed of 133 women with a median age of 59 years (range, 27-82 years) and the following stage groups: 0 (13.5%), I (40.6%), II (38.3%), and III (7.5%). The histologic subtypes of the primary tumor were invasive ductal carcinoma (74.4%), invasive lobular carcinoma (12.0%), and DCIS alone (13.5%). Residual carcinoma was present in the re-excision and completion mastectomy specimens in 55.4%, 14.3%, and 7.2% of women with an involved, close, and negative margin, respectively. In the 77 women with a noninvolved radial margin, the MRE of residual disease, if present, was {<=}10 mm in 97.4% (95% confidence interval 91.6-99.5) of cases. Larger MRE measurements were significantly associated with an involved margin (P<.001), tumor size >30 mm (P=.03), premenopausal status (P=.03), and negative progesterone receptor status (P=.05). Conclusions: A clinical target volume margin of 10 mm would encompass microscopic residual disease in >90% of women potentially eligible for PBRT after WLE with noninvolved resection margins.

Nguyen, Brandon T., E-mail: Brandon.Nguyen@act.gov.au [Department of Radiation Oncology, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Canberra Hospital, Radiation Oncology Department, Garran, ACT (Australia); Deb, Siddhartha [Department of Anatomical Pathology, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia) [Department of Anatomical Pathology, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Victorian Cancer Biobank, Cancer Council of Victoria, Carlton, Victoria (Australia); Fox, Stephen [Department of Anatomical Pathology, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia)] [Department of Anatomical Pathology, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Hill, Prudence [Department of Anatomical Pathology, St. Vincent's Hospital Melbourne, Fitzroy, Victoria (Australia)] [Department of Anatomical Pathology, St. Vincent's Hospital Melbourne, Fitzroy, Victoria (Australia); Collins, Marnie [Centre for Biostatistics and Clinical Trials, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia)] [Centre for Biostatistics and Clinical Trials, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Chua, Boon H. [Department of Radiation Oncology, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia) [Department of Radiation Oncology, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); University of Melbourne, Parkville, Victoria (Australia)

2012-12-01

133

Efficiency of a pendulum appliance for molar distalization related to second and third molar eruption stage  

Microsoft Academic Search

A modified pendulum appliance, including a distal screw and special preactivated pendulum springs (built-in straightening activation and toe-in bending), was used for bilateral maxillary molar distalization in 36 adolescent patients in various stages of the molar dentition. The patients were divided into 3 groups (PG 1-3) according to the stage of eruption of their second and third molars. In PG

Gero S. M Kinzinger; Ulrike B Fritz; Franz-Günter Sander; Peter R Diedrich

2004-01-01

134

Improving Dynamic Susceptibility Contrast MRI Measurement of Quantitative Cerebral Blood Flow using Corrections for Partial Volume and Nonlinear Contrast Relaxivity: a Xenon CT Comparative Study  

PubMed Central

Purpose To test whether dynamic susceptibility contrast MRI-based CBF measurements are improved with arterial input function (AIF) partial volume (PV) and nonlinear contrast relaxivity correction, using a gold-standard CBF method, xenon computed tomography (xeCT). Materials and Methods 18 patients with cerebrovascular disease underwent xeCT and MRI within 36 hrs. PV was measured as the ratio of the area under the AIF and the venous output function (VOF) concentration curves. A correction was applied to account for the nonlinear relaxivity of bulk blood (BB). Mean CBF was measured with both techniques and regression analyses both within and between patients were performed. Results Mean xeCT CBF was 43.3±13.7 ml/100g/min (mean±SD). BB correction decreased CBF by a factor of 4.7±0.4, but did not affect precision. The least-biased CBF measurement was with BB but without PV correction (45.8±17.2 ml/100 g/min, coefficient of variation [COV]=32%). Precision improved with PV correction, although absolute CBF was mildly underestimated (34.3±10.8 ml/100 g/min, COV=27%). Between patients correlation was moderate even with both corrections (R=0.53). Conclusion Corrections for AIF PV and nonlinear BB relaxivity improve bolus MRI-based CBF maps. However, there remain challenges given the moderate between-patient correlation, which limit diagnostic confidence of such measurements in individual patients. PMID:19787719

Zaharchuk, Greg; Bammer, Roland; Straka, Matus; Newbould, Rexford D; Rosenberg, Jarrett; Olivot, Jean-Marc; Mlynash, Michael; Lansberg, Maarten G; Schwartz, Neil E; Marks, Michael M; Albers, Gregory W; Moseley, Michael E

2010-01-01

135

Orthodontic extrusion of horizontally impacted mandibular molars  

PubMed Central

Objective: To introduce and evaluate a novel approach in treating horizontally impacted mandibular second and third molars. Materials and methods: An orthodontic technique was applied for treatment of horizontally impacted mandibular second and third molars, which included a push-type spring for rotation first, and then a cantilever for extrusion. There were 8 mandibular third molars (M3s) and 2 second molars (M2s) in this study. Tooth mobility, extraction time, the inclination and parallelism of the impacted tooth, alveolar bone height of the adjacent tooth, and the relationship of impacted M3 and the inferior alveolar nerve (IAN) were evaluated. Results: Two horizontally impacted M2s could be upright in the arch and good occlusal relationships were obtained after treatment. All impacted M3s were successfully separated from the IAN, without any neurologic consequences. The average extraction time was 5 minutes. There was a significant change in the inclination and parallelism of the impacted tooth after treatment. A new bone apposition with the average height of 3.2 mm was noted distal to the adjacent tooth. Conclusions: This two-step orthodontic technique as presented here may be a safe and feasible alternative in management of severely horizontally impacted mandibular molars, which achieves a successful separation of M3s from the IAN and an excellent position for M2s.

Ma, Zhigui; Yang, Chi; Zhang, Shanyong; Xie, Qianyang; Shen, Yuqing; Shen, Pei

2014-01-01

136

Molar and Modular Examples 1 Running head: ENHANCING LEARNING FROM MOLAR AND MODULAR  

E-print Network

that are to be integrated into a to-be- learned schema and therefore have to be processed in working memory s Gerjets, P., Scheiter, K., & Catrambone, R. (2006). Can learning from molar and modular worked examples © Elsevier Ltd. 2006. doi:10.1016/j.learninstruc.2006.02.007 Can Learning from Molar and Modular Worked

Paris-Sud XI, Université de

137

The Neanderthalian molar from Hunas, Germany.  

PubMed

In this paper, we present a well-preserved isolated human molar found in 1986 in the Hunas cave ruin, south-east Bavaria. The tooth was located at the bottom of layer F2, which belongs to a long stratigraphic sequence comprising faunal remains as well as archaeological levels (Mousterian). A stalagmite from layer P at the base of the stratigraphic sequence was recently dated to 79.373+/-8.237 ka (base) and 76.872+/-9.686 ka (tip) by TIMS-U/Th (Stanford University). We identified the tooth as a right (possibly third) mandibular molar. Characteristic parameters such as crown and root morphology, fissure pattern, enamel thickness, occlusal and interproximal wear, dental dimensions and indices, and radiological features indicate that the Hunas molar represents the tooth of a Neanderthal. This is corroborated by both the palaeontological and archaeological findings (Mousterian) of layer F2. PMID:16780842

Alt, K W; Kaulich, B; Reisch, L; Vogel, H; Rosendahl, W

2006-01-01

138

Influence of the partial volume correction method on 18F-fluorodeoxyglucose brain kinetic modelling from dynamic PET images reconstructed with resolution model based OSEM  

PubMed Central

Kinetic parameters estimated from dynamic 18F-fluorodeoxyglucose PET acquisitions have been used frequently to assess brain function in humans. Neglecting partial volume correction (PVC) for a dynamic series has been shown to produce significant bias in model estimates. Accurate PVC requires a space-variant model describing the reconstructed image spatial point spread function (PSF) that accounts for resolution limitations, including non-uniformities across the field of view due to the parallax effect. For OSEM, image resolution convergence is local and influenced significantly by the number of iterations, the count density, and background-to-target ratio. As both count density and background-to-target values for a brain structure can change during a dynamic scan, the local image resolution may also concurrently vary. When PVC is applied post-reconstruction the kinetic parameter estimates may be biased when neglecting the frame-dependent resolution. We explored the influence of the PVC method and implementation on kinetic parameters estimated by fitting 18F-fluorodeoxyglucose dynamic data acquired on a dedicated brain PET scanner and reconstructed with and without PSF modelling in the OSEM algorithm. The performance of several PVC algorithms was quantified with a phantom experiment, an anthropomorphic Monte Carlo simulation, and a patient scan. Using the last frame reconstructed image only for regional spread function (RSF) generation, as opposed to computing RSFs for each frame independently, and applying perturbation GTM PVC with PSF based OSEM produced the lowest magnitude bias kinetic parameter estimates in most instances, although at the cost of increased noise compared to the PVC methods utilizing conventional OSEM. Use of the last frame RSFs for PVC with no PSF modelling in the OSEM algorithm produced the lowest bias in CMRGlc estimates, although by less than 5% in most cases compared to the other PVC methods. The results indicate that the PVC implementation and choice of PSF modelling in the reconstruction can significantly impact model parameters. PMID:24052021

Bowen, Spencer L.; Byars, Larry G.; Michel, Christian J.; Chonde, Daniel B.; Catana, Ciprian

2014-01-01

139

Prevalence of asymmetric molar and canine relationship.  

PubMed

The purpose of this study was to investigate the prevalence and severity of occlusal asymmetries in the molar and canine regions in a large population-based sample of adolescent Kuwaitis. Using a stratified cluster sampling method, 1299 Kuwaiti adolescents (674 boys mean age 13.3 years and 625 girls mean age 13.2 years), representing approximately 6.7 per cent of that age stratum in the population, were examined clinically for sagittal molar and canine relationships, with a view to recording half and full-step asymmetries. In this sample, 1244 subjects were examined clinically, while for the remaining 55, pre-treatment study models were assessed. All subjects were in the early permanent dentition stage. Descriptive statistical analyses were used to determine the proportion of different molar and canine asymmetries. Antero-posterior asymmetries were found to be a distinctive and common feature of the dental arches, with half-step outweighing full-step asymmetries both in the anterior and posterior regions. The total prevalence of an asymmetric molar or canine relationship was 29.7 and 41.4 per cent, respectively, with more than 95 per cent falling in the mild category. Patient gender did not influence the prevalence or magnitude of asymmetry. The results showed a clinically significant prevalence of asymmetric molar and canine relationships, which were mainly in the category of half-step asymmetry. Class II half and full-step asymmetries were more prevalent than Class III asymmetries in the molar and canine regions. PMID:21742643

Behbehani, Faraj; Roy, Rino; Al-Jame, Badreia

2012-12-01

140

Dependence of the volume characteristics and viscosity of solutions of methanol-octane-naphthalene on composition at 25°C  

NASA Astrophysics Data System (ADS)

The limiting solubility of naphthalene in a mixture of methanol-octane at 25°C is determined via isothermal saturation. The kinematic viscosity of a mixture of methanol-octane-naphthalene is measured at 25°C. Data on the density of triple mixtures of methanol-octane-naphthalene, used to calculate the partial and apparent molar volumes of naphthalene, are obtained with a high degree of accuracy. The obtained results are discussed in terms of the interactions that occur in solution.

Dyshin, A. A.; Eliseeva, O. V.; Kiselev, M. G.

2014-10-01

141

Effect of partial volume correction on estimates of the influx and cerebral metabolism of 6-[(18)F]fluoro-L-dopa studied with PET in normal control and Parkinson's disease subjects.  

PubMed

The poor spatial resolution of positron emission tomography (PET) is a limiting factor in the accurate assay of physiological processes investigated by compartmental modeling of tracer uptake and metabolism in living human brain. The radioactivity concentration in a region-of-interest is consequently altered by loss of signal from that structure and contamination from adjacent brain regions, phenomena known as partial volume effects. We now apply an MRI-based algorithm to compensate for partial volume effects in the special case of compartmental modeling of the cerebral uptake of 6-[(18)F]fluoro-L-dopa (FDOPA), an exogenous substrate of dopa decarboxylase. High-resolution MRI scans were obtained from normal volunteers (n = 4) and patients with Parkinson's disease (n = 4) in order to segment specific brain regions and calculate the partial volume correction factors. Dynamic 2D PET scans were acquired during 90 min following intravenous infusion of FDOPA. After partial volume correction, the apparent net blood-brain clearance of FDOPA (K(i)) was greatly increased in caudate and putamen of normal subjects and in caudate of Parkinson's disease patients. The equilibrium distribution volume of FDOPA (V(D)(e)) in cerebral cortex increased by 35% in all subjects. Using a two-compartment model, the relative activity of dopa decarboxylase with respect to FDOPA (k(D)(3)) in the basal ganglia was increased 2-3 times in normal subjects, to the range obtained previously in brain of living rat. The partial volume correction also increased the magnitude of k(D)(3) in caudate of Parkinson's disease patients, but did not alter k(D)(3) in putamen. A three-compartment model correcting for elimination of decarboxylated metabolites also yielded higher estimates of k(D)(3), but with a penalty in precision of the estimates. Together, these observations suggest that the limited spatial resolution of PET results in substantial underestimation of the true rate of FDOPA uptake and metabolism in vivo, and may also tend to obscure regional heterogeneity in the neurochemical pathology of Parkinson's disease. PMID:10881028

Rousset, O G; Deep, P; Kuwabara, H; Evans, A C; Gjedde, A H; Cumming, P

2000-08-01

142

Pathological (late) fractures of the mandibular angle after lower third molar removal: a case series  

PubMed Central

Introduction Pathological (late) fracture of the mandibular angle after third molar surgery is very rare (0.005% of third molar removals). There are 94 cases reported in the literature; cases associated with osseous pathologies such as osteomyelitis or any local and systemic diseases that may compromise mandibular bone strength have not been included. We describe three new cases of pathological (late) fracture of the mandibular angle after third molar surgery. Case presentations The first patient was a 27-year-old Caucasian man who had undergone surgical removal of a 3.8, mesioangular variety, class II-C third molar 20 days before admission to our clinic. The fracture of his left mandibular angle, complete and composed, occurred during chewing. The second patient was a 32-year-old Caucasian man. He had undergone surgical removal of a 3.8, mesioangular variety, class II-B third molar 22 days before his admission. The fracture, which occurred during mastication, was studied by computed tomography that showed reparative tissue in the fracture site. The third patient was a 36-year-old Caucasian man who had undergone surgical removal of a 3.8, vertical variety, class II-C third molar 25 days before the observation. In this case the fracture of his mandibular angle was oblique (unfavorable), complete and composed. The fracture had occurred during chewing. We studied the fracture by optical projection tomography and computed tomography. All of the surgical removals of the 3.8 third molars, performed by the patients’ dentists who had more than 10 years of experience, were difficult. We treated the fractures with open surgical reduction, internal fixation by titanium miniplates and intermaxillary elastic fixation removed after 6 weeks. Conclusions The literature indicates that the risk of pathological (late) fracture of the mandibular angle after third molar surgery for total inclusions (class II-III, type C) is twice that of partial inclusions due to the necessity of ostectomies more generous than those for partial inclusions. Other important factors are the anatomy of the teeth and the features of the teeth roots. These fractures predominantly occur in patients who are older than 25 years. The highest incidence (67.8% of cases) is found in the second and third week postsurgery. We emphasize that before the third molar surgery it is extremely important to always provide adequate instructions to the patient in order to avoid early masticatory loads and prevent this rare event. PMID:23631557

2013-01-01

143

Influence of the partial volume correction method on 18F-fluorodeoxyglucose brain kinetic modelling from dynamic PET images reconstructed with resolution model based OSEM  

NASA Astrophysics Data System (ADS)

Kinetic parameters estimated from dynamic 18F-fluorodeoxyglucose (18F-FDG) PET acquisitions have been used frequently to assess brain function in humans. Neglecting partial volume correction (PVC) for a dynamic series has been shown to produce significant bias in model estimates. Accurate PVC requires a space-variant model describing the reconstructed image spatial point spread function (PSF) that accounts for resolution limitations, including non-uniformities across the field of view due to the parallax effect. For ordered subsets expectation maximization (OSEM), image resolution convergence is local and influenced significantly by the number of iterations, the count density, and background-to-target ratio. As both count density and background-to-target values for a brain structure can change during a dynamic scan, the local image resolution may also concurrently vary. When PVC is applied post-reconstruction the kinetic parameter estimates may be biased when neglecting the frame-dependent resolution. We explored the influence of the PVC method and implementation on kinetic parameters estimated by fitting 18F-FDG dynamic data acquired on a dedicated brain PET scanner and reconstructed with and without PSF modelling in the OSEM algorithm. The performance of several PVC algorithms was quantified with a phantom experiment, an anthropomorphic Monte Carlo simulation, and a patient scan. Using the last frame reconstructed image only for regional spread function (RSF) generation, as opposed to computing RSFs for each frame independently, and applying perturbation geometric transfer matrix PVC with PSF based OSEM produced the lowest magnitude bias kinetic parameter estimates in most instances, although at the cost of increased noise compared to the PVC methods utilizing conventional OSEM. Use of the last frame RSFs for PVC with no PSF modelling in the OSEM algorithm produced the lowest bias in cerebral metabolic rate of glucose estimates, although by less than 5% in most cases compared to the other PVC methods. The results indicate that the PVC implementation and choice of PSF modelling in the reconstruction can significantly impact model parameters.

Bowen, Spencer L.; Byars, Larry G.; Michel, Christian J.; Chonde, Daniel B.; Catana, Ciprian

2013-10-01

144

The Neanderthalian molar from Hunas, Germany  

Microsoft Academic Search

In this paper, we present a well-preserved isolated human molar found in 1986 in the Hunas cave ruin, south-east Bavaria. The tooth was located at the bottom of layer F2, which belongs to a long stratigraphic sequence comprising faunal remains as well as archaeological levels (Mousterian). A stalagmite from layer P at the base of the stratigraphic sequence was recently

K. W. Alt; L. Reisch; H. Vogel; W. Rosendahl

2006-01-01

145

4. New perspectives on chimpanzee and human molar crown development  

E-print Network

within humans. Within upper molars, mesiopalatal cusps (protocones) show thicker cuspal enamel and longer crown formation time than mesiobuccal cusps (paracones). Within lower molars, mesiobuccal cusps4. New perspectives on chimpanzee and human molar crown development T.M. SMITH Human Evolution

Smith, Tanya M.

146

A comparative study on the volume and localization of the internal gross target volume defined using the seroma and surgical clips based on 4DCT scan for external-beam partial breast irradiation after breast conserving surgery  

PubMed Central

Background To explore the volume and localization of the internal gross target volume defined using the seroma and/or surgical clips based on the four-dimensional computed tomography (4DCT) during free-breathing. Methods Fifteen breast cancer patients after breast-conserving surgery (BCS) were recruited for EB-PBI. On the ten sets CT images, the gross target volume formed by the clips, the seroma, both the clips and seroma delineated by one radiation oncologist and defined as GTVc, GTVs and GTVc?+?s, respectively. The ten GTVc, GTVs and GTVc?+?s on the ten sets CT images produced the IGTVc, IGTVs, IGTVc?+?s, respectively. The IGTV volume and the distance between the center of IGTVc, IGTVs, IGTVc?+?s were all recorded. Conformity index (CI), degree of inclusion (DI) were calculated for IGTV/IGTV, respectively. Results The volume of IGTVc?+?s were significantly larger than the IGTVc and IGTVs (p?volume difference and spatial mismatch between the IGTVs delineated based on the surgical clips and seroma. The IGTV defined as the seroma and surgical clips provided the best overall representation of the ‘true’ moving GTV. PMID:24646022

2014-01-01

147

Clinical significance of computed tomography assessment for third molar surgery  

PubMed Central

Surgical extraction of the third molar is the most commonly performed surgical procedure in the clinical practice of oral surgery. Third molar surgery is warranted when there is inadequate space for eruption, malpositioning, or risk for cyst or odontogenic tumor formation. Preoperative assessment should include a detailed morphologic analysis of the third molar and its relationship to adjacent structures and surrounding tissues. Due to developments in medical engineering technology, computed tomography (CT) now plays a critical role in providing the clear images required for adequate assessment prior to third molar surgery. Removal of the maxillary third molar is associated with a risk for maxillary sinus perforation, whereas removal of the mandibular third molar can put patients at risk for a neurosensory deficit from damage to the lingual nerve or inferior alveolar nerve. Multiple factors, including demographic, anatomic, and treatment-related factors, influence the incidence of nerve injury during or following removal of the third molar. CT assessment of the third molar prior to surgery can identify some of these risk factors, such as the absence of cortication between the mandibular third molar and the inferior alveolar canal, prior to surgery to reduce the risk for nerve damage. This topic highlight presents an overview of the clinical significance of CT assessment in third molar surgery. PMID:25071882

Nakamori, Kenji; Tomihara, Kei; Noguchi, Makoto

2014-01-01

148

Evaluating controlling factors to Al(i)/(Ca + Mg) molar ratio in acidic soil water, southern and southwestern China: multivariate approach.  

PubMed

Al(i)/(Ca + Mg) molar ratio in soil water has been used as an indicator to the effects of acid deposition on terrestrial ecosystems. However, the main factors controlling this ratio have not been well documented in southern and southwestern China. In this study, we presented the variation in inorganic aluminum (Al(i)) and Al(i)/(Ca + Mg) molar ratio in different sites and soil horizons based on two to three years monitoring data, and evaluated the main factors controlling Al(i)/(Ca + Mg) molar ratio using principle component analysis (PCA) and partial least square (PLS) regression. Monitoring data showed although Al(i)/(Ca + Mg) molar ratios in most soil water were lower than assumed critical 1.0, higher molar ratios were found in some soil water at TSP and LXH site. Besides acid loading, both soil properties and soil water chemistry affected the value of Al(i)/(Ca + Mg) molar ratio in soil water. Partial least square (PLS) indicated that they had different relative importance in different soil horizons. In A-horizon, soil aluminum saturation (AlS) had higher influence on Al(i)/(Ca + Mg) molar ratio than soil water chemistry did; higher soil aluminum saturation (AlS) led to higher Al(i)/(Ca + Mg) molar ratio in soil water. In the deeper horizons (i.e., B(1)-, B(2)- and BC-horizon), inorganic aluminum (Al(i)) in soil water had more and more important role in regulating Al(i)/(Ca + Mg) molar ratio. On regional scale, soil aluminum saturation (AlS) as well as cation exchange capacity (CEC) was the dominant factor controlling Al(i)/(Ca + Mg) molar ratio. This should be paid enough attention on when making regional acid rain control policy in China. PMID:17057971

Guo, Jing-Heng; Zhang, Xiao-Shan; Vogt, Rolf D; Xiao, Jin-Song; Zhao, Da-Wei; Xiang, Ren-Jun; Luo, Jia-Hai

2007-06-01

149

28 Applied Rheology Volume 15 Issue 1  

E-print Network

28 Applied Rheology Volume 15 · Issue 1 Influence of the Molar Mass Distribution: kulicke@chemie.uni-hamburg.de Received: 5.7.04, Final version: 17.12.04 Abstract: Commercially available The influence of the molar mass distribution (usually referred to as MWD (molecular weight distribution

150

Mitochondrial and cytoplasmic ribosomes from mammalian tissues. Further characterization of ribosomal subunits and validity of buoyant-density methods for determination of the chemical composition and partial specific volume of ribonucleoprotein particles  

PubMed Central

1. At 0–4°C mitochondrial ribosomes (55S) dissociate into 39S and 29S subunits after exposure to 300mm-K+ in the presence of 3.0mm-Mg2+. When these subunits are placed in a medium containing a lower concentration of K+ ions (25mm), approx. 75% of the subparticles recombine giving 55S monomers. 2. After negative staining the large subunits (20.3nm width) usually show a roundish profile, whereas the small subunits (12nm width) show an elongated, often bipartite, profile. The dimensions of the 55S ribosomes are 25.5nm×20.0nm×21.0nm, indicating a volume ratio of mitochondrial to cytosol ribosomes of 1:1.5. 3. The 39S and 29S subunits obtained in high-salt media at 0–4°C have a buoyant density of 1.45g/cm3; from the rRNA content calculated from buoyant density and from the rRNA molecular weights it is confirmed that the two subparticles have weights of 2.0×106 daltons and 1.20×106 daltons; the weights of the two subunits of cytosol ribosomes are 2.67×106 and 1.30×106 daltons. 4. The validity of the isodensity-equilibrium-centrifugation methods used to calculate the chemical composition of ribosomes was reinvestigated; it is confirmed that (a) reaction of ribosomal subunits with 6.0% (v/v) formaldehyde at 0°C is sufficient to fix the particles, so that they remain essentially stable after exposure to dodecyl sulphate or centrifugation in CsCl, and (b) the partial specific volume of ribosomal subunits is a simple additive function of the partial specific volumes of RNA and protein. The RNA content is linearly related to buoyant density by the equation RNA (% by wt.)=349.5?(471.2×1/?CsCl), where 1/?CsCl=[unk]RNP (partial specific volume of ribonucleoprotein). 5. The nucleotide compositions of the two subunit rRNA species of mitochondrial ribosomes from rodents (42% and 43% G+C) are distinctly different from those of cytoplasmic ribosomes. ImagesPLATE 1PLATE 2 PMID:563718

Sacchi, Ada; Ferrini, Ugo; Londei, Paola; Cammarano, Piero; Maraldi, Nadir

1977-01-01

151

Brodie bite with an extracted mandibular first molar in a young adult: a case report.  

PubMed

Total buccal crossbites are rare, but, when they occur, they can be extremely difficult to correct, even with surgery and orthodontics. In most patients with in-locking crossbites, the maxillary teeth erupt past their mandibular antagonists, creating severe occlusal difficulties. This article presents an adult patient with scissors-bite or partial telescoping bite bilaterally in the posterior region and an extracted mandibular first molar on the right side. She was treated with expansion of the mandibular arch, and the subsequent open bite was closed with the help of masticatory muscle exercises and high-pull headgear. The second and third molars were uprighted and moved mesially to close the extraction spaces. PMID:20451791

Chugh, Vinay K; Sharma, Vijay P; Tandon, Pradeep; Singh, Gyan P

2010-05-01

152

Adjacent dentigerous cysts with the ectopic displacement of a third mandibular molar and supernumerary (forth) molar: a rare occurrence.  

PubMed

Dentigerous cysts are the most common odontological cysts of the jaws, being associated with the crowns of permanent teeth, especially unerupted mandibular third molars. Multiple dentigerous cysts are rare and most often occur in association with a developmental syndrome. This article presents an unusual case of nonsyndromic adjacent dentigerous cysts associated with a mandibular third molar and a supernumerary molar. This occurrence has not been previously reported. PMID:19464637

McCrea, Shane

2009-06-01

153

Partial priapism.  

PubMed

With only 34 prior cases in world literature, partial priapism (PP), also called partial segmental thrombosis of the corpus cavernosum, is a rare urological condition. The aetiology and treatment of PP is still unclear, but bicycle riding, trauma, drug usage, sexual intercourse, haematological diseases and ?-blockers have been associated with PP. In this case report and world literature review, we describe the case of a 50-year-old man suffering from PP after ingesting 100 mg of sildenafil. The patient was treated with a surgical incision for corpus cavernosum and clot evacuation, as a conservative treatment of PP was not feasible due to severe pain and unresponsiveness to analgesics. PMID:23933863

Hoyerup, Peter; Azawi, Nessn Htum

2013-01-01

154

Clinical decision making on extensive molar restorations.  

PubMed

SUMMARY Extensive loss of posterior tooth substance, which traditionally was restored with amalgam or indirect restorations, is more commonly being restored with resin-based composite restorations. Using a questionnaire, we aimed to survey dentists' clinical decision making when restoring extensive defects in posterior molar teeth. The questionnaire, which included questions on background information from the dentists, clinical cases with treatment options, and general questions about restoring extensive posterior defects, was sent to 476 dentists. The response rate was 59%. Multiple logistic regressions were used to investigate the different associations. Most of the respondents preferred a direct composite restoration when one cusp was missing, while indirect restorations were most preferred when replacing three or four cusps. Younger dentists and dentists working in the private sector had a greater tendency to choose an indirect technique compared with older colleagues. Generally, the most important influencing factor in clinical decision making was the amount of remaining tooth substance. Factors that appeared to be less important were dental advertisements, use of fluoride, and dietary habits. Female dentists perceived factors such as oral hygiene, patient requests, and economy to be more important than did their male colleagues. PMID:24828135

Laegreid, T; Gjerdet, Nr; Johansson, A; Johansson, A-K

2014-01-01

155

Partial priapism.  

PubMed

We report the third documented case of partial priapism. The proximal right corpus was distended and separated from the distral flaccid corpus by a transverse membrane. Histologic examination revealed the obstructing lesion to be owing to thrombosis of vascular erectile tissue probably secondary to trauma. Excision of this membrane promptly cured the condition. PMID:7411706

Johnson, G R; Corriers, J N

1980-07-01

156

Epilepsy (partial)  

PubMed Central

Introduction About 3% of people will be diagnosed with epilepsy during their lifetime, but about 70% of people with epilepsy eventually go into remission. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of starting antiepileptic drug treatment following a single seizure? What are the effects of drug monotherapy in people with partial epilepsy? What are the effects of additional drug treatments in people with drug-resistant partial epilepsy? What is the risk of relapse in people in remission when withdrawing antiepileptic drugs? What are the effects of behavioural and psychological treatments for people with epilepsy? What are the effects of surgery in people with drug-resistant temporal lobe epilepsy? We searched: Medline, Embase, The Cochrane Library, and other important databases up to July 2009 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 83 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: antiepileptic drugs after a single seizure; monotherapy for partial epilepsy using carbamazepine, gabapentin, lamotrigine, levetiracetam, phenobarbital, phenytoin, sodium valproate, or topiramate; addition of second-line drugs for drug-resistant partial epilepsy (allopurinol, eslicarbazepine, gabapentin, lacosamide, lamotrigine, levetiracetam, losigamone, oxcarbazepine, retigabine, tiagabine, topiramate, vigabatrin, or zonisamide); antiepileptic drug withdrawal for people with partial or generalised epilepsy who are in remission; behavioural and psychological treatments for partial or generalised epilepsy (biofeedback, cognitive behavioural therapy (CBT), educational programmes, family counselling, relaxation therapy (alone or plus behavioural modification therapy, yoga); and surgery for drug-resistant temporal lobe epilepsy ( lesionectomy, temporal lobectomy, vagus nerve stimulation as adjunctive therapy). PMID:21549021

2011-01-01

157

Influence of third molars in Le Fort 1 osteotomy  

PubMed Central

Background: The influence of maxillary third molar (M3) on the outcomes of Le Fort 1 osteotomy is not deeply investigated. Aim: To investigate the influence of M3 on Le Fort 1 osteotomies. Setting: Tertiary Referral Center, operated by a single surgeon, prospective study. Period: January 2005 to December 2010. Patients: Consecutive Le Fort 1 osteotomy patients with both M3. Predictor Variable: Gender, position, M3 root morphology, and degree of impaction. Outcome Variable: Time taken after all osteotomy cuts to point of time when maxilla is placed in predetermined plane. Result: A total of 658 M3 in line of cut were studied. Of all M3, 312 were impacted, 28.9% were partially impacted and 23.7% were erupted. Of all the M3, 2.9% had their cuspal tips above the horizontal cut, 13.8% along the line of cut, and in 20.7% below the line but not erupted. Buccoverted tooth took shortest time (7.74 minutes), while palatoversion required more time (8.44 minutes) (P = 0.000). When the cuspal tip of M3 was located above the horizontal line of cut, the mean time required to achieve the planned position was 7 minutes, while the completely erupted teeth took a mean of 8.24 minutes (P = 0.000). Conclusion: When the M3 is placed higher, it takes lesser time to prepare basal bone to receive the maxilla at its predetermined level. Angulation of M3 influences the outcome. Deeply placed M3 reduces the manipulation of the greater pterygoid palatine vessels in the area thereby minimizing the bleeding in the surgical field. PMID:23482647

Balaji, S. M.

2011-01-01

158

Molar absorptivity and color characteristics of acylated and non-acylated pelargonidin-based anthocyanins.  

PubMed

The effects of glycosylation and acylation on the spectral characteristics, molar absorptivity, and color attributes of purified acylated and non-acylated pelargonidin derivatives were compared. Pigments were obtained from strawberries, radishes, red-fleshed potatoes, and partially hydrolyzed radish pigments. Individual pigments were isolated by using semipreparative HPLC. Spectral and color (CIELch) attributes of purified pigments were measured. Molar absorptivity ranged from 15 600 to 39 590 for pelargonidin-3-glucoside (pg-3-glu) and pg-3-rutinoside-5-glucoside acylated with p-coumaric acid, respectively. The presence of cinnamic acid acylation had a considerable impact on spectral and color characteristics, causing a bathochromic shift of lambda(max). Sugar substitution also played an important role, with a hypsochromic shift caused by the presence of glycosylation. Pg-3, 5-diglu and pg-3,5-triglu possessed a higher hue angle (>40 degrees ) than the other pg derivatives at pH 1.0, corresponding to the yellow-orange region of the color solid. Acylation with malonic acid did not affect lambda(max) and showed little effect on color characteristics. The solvent system had an effect not only on the molar absorptivity, but also on the visual color characteristic of the pigments. PMID:10552862

Giusti, M M; Rodríguez-Saona, L E; Wrolstad, R E

1999-11-01

159

Investigation of third molar impaction in Turkish orthodontic patients: Prevalence, depth and angular positions  

PubMed Central

Objective: We aimed to investigate the prevalence, distribution, angular position, and depth of third molar impaction in a Turkish orthodontic patient population. Materials and Methods: We retrospectively reviewed the panoramic radiographs, intraoral photographs, and dental casts of 207 patients (62 men and 145 women; age 20-39 years) who had undergone orthodontic treatment at a university department of orthodontics for impacted third molars (ITMs). A comprehensive chart review of all subjects was conducted. Patient and treatment-related data were recorded in a digital database for comparative analysis. Results: The prevalence of ITMs was 54.1%, and no statistically significant gender differences were evident (61.3% in men and 51.0% in women; P = 0.23). The frequency of maxillary ITMs was 49.3% (148 of 300 teeth) while that of mandibular ITMs was 50.7% (152 of 300 teeth). The most frequently observed angulations of impaction were mesioangular for the mandible (65.1%), and distoangular for the maxilla (64.2%). Of all the ITMs analysed, 61% were partially buried in bone and 39% were completely buried. Conclusions: Third molar impaction was evident in 54.1% of a group of Turkish orthodontic patients aged 20-39 years, and there was no statistically significant gender bias. Mesioangular and distoangular inclinations were the most common in the mandible and the maxilla, respectively. PMID:24966737

Topkara, Ahu; Sari, Zafer

2013-01-01

160

Molar heat capacity and entropy of calcium metal  

USGS Publications Warehouse

The heat capacity of calcium has been measured at 85 mean temperatures between T ??? 8 K and T ??? 369 K using an adiabatically-shielded calorimeter in an intermittent heating mode. At T = 298.15 K, the recommended values for the molar heat capacity, molar entropy, and molar enthalpy increment referred to T = 0 are (25.77 ?? 0.08) J??K-1??mol-1, (42.90 ?? 0.11) J??K-1??mol-1, and (5811 ?? 12) J??mol-1, respectively. The uncertainties are twice the standard deviation of the mean. ?? 1997 Academic Press Limited.

Hemingway, B.S.; Robie, R.A.; Chase, M.W.

1997-01-01

161

Modification of uprighting spring for derotation of second molars.  

PubMed

One of the most efficient ways for the correction of rotated upper molars is derotation with a transpalatal arch, but this appliance is usually favourable when the need for correction is same on both sides of the dental arch. Derotation of unilateral upper second molar is a difficult task, especially when there is no accessible tooth/ any attachment is available distal to it for the application of couple forces. We have designed a modification of uprighting spring which is far more convenient than using the conventional method of TPA for derotation of unilateral upper second molar. PMID:24640073

Mallikarjun, Vankre; Rachala, Madhukar Reddy; Aileni, Kaladhar Reddy; Jaipal, Pyata Reddy

2013-01-01

162

Orthognathic treatment with autotransplantation of a third molar.  

PubMed

Autotransplantation is an option for tooth replacement when a suitable tooth is available and anatomic circumstances are favorable. This case report describes successful orthognathic treatment that was combined with autotransplantation of a maxillary third molar. A 20-year-old woman had mandibular protrusion and facial asymmetry. Five years previously, her mandibular right first molar had been extracted because of dental caries. After preoperative orthodontic treatment, we performed a LeFort I procedure and a bilateral intraoral vertical ramus osteotomy to correct the patient's mandibular protrusion and facial asymmetry. During the postoperative orthodontic treatment, the maxillary left third molar was autotransplanted into the mandibular right first molar site. The total treatment period was 24 months. As a result of these therapeutic treatments, the patient's facial appearance was improved, and an implant was unnecessary. The autotransplanted tooth effectively supported the adjacent teeth and maintained her chewing ability. PMID:24182590

Choi, Sung-Hwan; Hwang, Chung-Ju

2013-11-01

163

Determining Molar Combining Ratios Using Radioisotopes--A Student Experiment  

ERIC Educational Resources Information Center

Outlines an experimental procedure in which an iodine radioisotope is used to determine molar combining ratios of lead and silver with the iodine. Tables and graphs show the definitive results that should be attainable. (CP)

Sears, Jerry A.

1976-01-01

164

Mandibular first molar with a radix entomolaris: an endodontic dilemma.  

PubMed

It is known that the mandibular first molar can display significant anatomical variations namely the number of root canals, the number of roots and morphology. Mandibular molars may sometimes have an additional root located lingually (the radix entomolaris) or buccally (the radix paramolaris). If encountered, an awareness and understanding of this unusual root and its canal morphology can contribute to the successful outcome of root canal treatment. This case report discusses endodontic treatment of a mandibular first molar with a radix entomolaris, which is a rare entity and poses as an endodontic dilemma for the clinician with respect to diagnosis and subsequent treatment. Clinicians should be aware of these unusual root morphologies in the mandibular first molar which needs strategic treatment as unfilled canals remain a nidus for infection and can compromise treatment outcome. PMID:24910685

Sarangi, Priyanka; Uppin, Veerendra M

2014-01-01

165

40 CFR 1065.642 - SSV, CFV, and PDP molar flow rate calculations.  

Code of Federal Regulations, 2011 CFR

...false SSV, CFV, and PDP molar flow rate calculations. 1065...PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING...642 SSV, CFV, and PDP molar flow rate calculations. This section...equations for calculating molar flow rates from various flow...

2011-07-01

166

40 CFR 1065.642 - SSV, CFV, and PDP molar flow rate calculations.  

Code of Federal Regulations, 2012 CFR

...false SSV, CFV, and PDP molar flow rate calculations. 1065...PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING...642 SSV, CFV, and PDP molar flow rate calculations. This section...equations for calculating molar flow rates from various flow...

2012-07-01

167

40 CFR 1065.642 - SSV, CFV, and PDP molar flow rate calculations.  

Code of Federal Regulations, 2010 CFR

...false SSV, CFV, and PDP molar flow rate calculations. 1065...PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING...642 SSV, CFV, and PDP molar flow rate calculations. This section...equations for calculating molar flow rates from various flow...

2010-07-01

168

40 CFR 1065.642 - SSV, CFV, and PDP molar flow rate calculations.  

Code of Federal Regulations, 2013 CFR

...false SSV, CFV, and PDP molar flow rate calculations. 1065...PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING...642 SSV, CFV, and PDP molar flow rate calculations. This section...equations for calculating molar flow rates from various flow...

2013-07-01

169

Preliminary Evaluation of Sodium Hypochlorite for Pulpotomies in Primary Molars  

Microsoft Academic Search

Purpose: The purpose of this study was to compare the effectiveness of 5% sodium hypo- chlorite (NaOCl) to that of ferric sulfate (FeSO4) as a pulpotomy medicament in decayed primary molars. Methods: Healthy subjects between 4 and 9 years with at least 2 primary molars need- ing pulpotomy consented to receive either NaOCl or FeSO4 and restoration with IRM base\\/stainless

Kaaren G. Vargas; Brett Packham; David Lowman

2006-01-01

170

The vasculogenesis--a possible histological identification criterion for the molar pregnancy.  

PubMed

The benign hydatidiform mole (partial and complete) practically represents an associated pathology of the first trimester miscarriage; it is considered that it represents the initial pathology, which, evolutionally, may be followed by the appearance of invasive mole and choriocarcinoma. The authors have studied clinical and cytogenetical 61 cases selected according to some specific criteria for the suspicion of molar pregnancy or hydropic abortion and 21 cases that represented the control group made by patients with normal pregnancy which have been presented for legal abortion. In all cases has been made a histological exam and has been studied the vasculogenesis by immunohistochemistry labeling for CD31 and CD34. Following-up the results has been established a number of histological and immunohistochemical criteria for the evaluation and differentiation of various molar pregnancy types and the vasculogenesis characteristics. The most important differential diagnosis criteria between partial and complete mole is represented by the trophoblast disposition and the atypical trophoblast in the complete mole. PMID:21424033

Novac, Liliana; Niculescu, Mihaela; Manolea, Maria Magdalena; Iliescu, D; Georgescu, Claudia Valentina; Com?nescu, Al; Cernea, N; Enache, Andreea

2011-01-01

171

First permanent molar root development arrest associated with compound odontoma.  

PubMed

Trauma or infection to the primary tooth may have deleterious effects on the underlying developing tooth buds. Anatomically the root apices of primary teeth are in close proximity to the developing permanent tooth buds; hence spread of infection originating from pulp necrosis of primary tooth may not only affect the underlying tooth bud but may also affect the adjacent tooth buds. The extent of malformation depends on the developmental stage of tooth or the age of patient. Presented here is a rare case of complete arrest of maxillary first permanent molar root growth due to spread of periapical infection originating from second primary molar leading to failure of its eruption and finally extraction. Histopathlogical analysis revealed compound odontoma associated with maxillary first permanent molar. PMID:23832997

Gunda, Sachin A; Patil, Anil; Varekar, Aniruddha

2013-01-01

172

- and Low-Molar Liquid Crystal Mixtures for Photorefractive Applications  

NASA Astrophysics Data System (ADS)

We describe a highly efficient photorefractive material possessing high-molar-mass liquid crystal (H-LC), low-molar-mass liquid crystal (L-LC), and photoconductive agent. These photorefractive high- and low-molar-mass liquid crystal mixtures (HL-LCMs) show high-performance in a thick grating regime (Bragg regime) under low dc electric fields (< 1 V/?m). The photorefractive properties are strongly dependent on the concentration of the H-LC. The fastest response time of 70 ms is achieved with a gain coefficient of 213 cm-1 in the case of 10 wt% of the H-LC with 0.18 V/?m. The largest gain coefficient of over 600 cm-1 is achieved with the response time of 2.6 s in the case of 40 wt% of the H-LC with 0.7 V/?m. In addition, our future directions in this research area are also presented.

Ono, Hiroshi; Kawatsuki, Nobuhiro

173

Anxiety and extraction of third molars in Turkish patients.  

PubMed

Preoperative anxiety is widespread and adversely affects a patient's physical and psychological outcome. Extraction of third molars is common, and many patients complain of anxiety and emotional disturbance. We assessed the anxiety of patients in Turkey before extraction of third molars. A total of 120 patients were admitted for removal of one or more third molars under local anaesthesia. The Amsterdam Preoperative Anxiety and Information Scale (APAIS) and Spielberger's State Trait Anxiety Inventory (STAI) were used to evaluate anxiety. The results showed that women were significantly more anxious than men; women who had not had a previous operation were more anxious than other women; there was no difference in the anxiety scores of patients who had previously had a local anaesthetic and those who had not; there were no differences in anxiety as measured by trait scores; patients who wanted a lot of information were more anxious. PMID:15544887

Garip, Hasan; Abali, Osman; Göker, Kamil; Göktürk, Ulkü; Garip, Yildiz

2004-12-01

174

Paramolar - A supernumerary molar: A case report and an overview  

PubMed Central

Paramolar is a supernumerary molar usually small and rudimentary, most commonly situated buccally or palatally to one of the maxillary molars. Paramolar is a developmental anomaly and has been argued to arise from a combination of genetic and environmental factors. Reports of this entity are rarely found in the dental literature. This article presents a case report of an unusual occurrence of a paramolar in the maxilla in otherwise a healthy individual. In addition, literature review, prevalence, classification, etiology, complications, diagnosis, and therapeutic strategies that may be adopted when supernumeraries occurs have been discussed. PMID:23559961

Nayak, Gurudutt; Shetty, Shashit; Singh, Inderpreet; Pitalia, Deepti

2012-01-01

175

Treatment of Ectopic Mandibular Second Permanent Molar with Elastic Separators  

PubMed Central

Ectopic eruption is a developmental disturbance in which the tooth fails to follow its normal eruption pathway. Ectopic eruption of the second molar is relatively rare. This paper presents the case of thirteen-year-old male with an ectopic mandibular second permanent molar. The condition was corrected with surgical exposure and placement of elastic separators. This case report lays emphasis on the practice of basic methods to obtain acceptable results rather than extensive surgical or orthodontic corrections. It is advised that ectopic teeth should not be neglected especially when it concerns developing caries and malocclusion. PMID:25050182

Rajesh, R.; Naveen, V.; Amit, S.; Baroudi, Kusai; Sampath Reddy, C.; Namineni, Srinivas

2014-01-01

176

Partial oxidation catalyst  

DOEpatents

A two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion. The dehydrogenation portion is a group VIII metal and the oxide-ion conducting portion is selected from a ceramic oxide crystallizing in the fluorite or perovskite structure. There is also disclosed a method of forming a hydrogen rich gas from a source of hydrocarbon fuel in which the hydrocarbon fuel contacts a two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion at a temperature not less than about 400.degree. C. for a time sufficient to generate the hydrogen rich gas while maintaining CO content less than about 5 volume percent. There is also disclosed a method of forming partially oxidized hydrocarbons from ethanes in which ethane gas contacts a two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion for a time and at a temperature sufficient to form an oxide.

Krumpelt, Michael (Naperville, IL); Ahmed, Shabbir (Bolingbrook, IL); Kumar, Romesh (Naperville, IL); Doshi, Rajiv (Downers Grove, IL)

2000-01-01

177

Inflammatory root resorption in primary molars: prevalence and associated factors.  

PubMed

This study aimed at determining the prevalence of inflammatory root resorption and associated factors in 1068 primary mandibular molars in 453 children 3 to 12 years of age. Age, dental history and medical history were recorded using a questionnaire administered to the children's parents/caregivers. Previously trained and calibrated examiners assessed radiographic images of the primary molars by direct observation, with the aid of a viewing box. Root resorption (physiological or inflammatory), dental crown status (healthy, carious with no pulp involvement, carious with pulp involvement and evidence of restoration), and pulpotomy or pulpectomy were determined. Data analysis involved descriptive statistics, the chi-square test and a multiple logistic regression (p < 0.05). The prevalence of inflammatory root resorption was 16.2% (n = 173). The male gender (OR: 1.4; 95% CI), the 3-to-7-years age bracket (OR: 1.5; 95% CI), an unhealthy dental crown (OR: 8.7; 95% CI), caries with pulp involvement (OR: 7.4; 95% CI), pulpotomy (OR: 3.1; 95% CI), and pulpectomy (OR: 5.4; 95% CI) were risk factors for the occurrence of inflammatory root resorption in primary molars. In conclusion, the prevalence of inflammatory root resorption in the present sample was 16.2%. Gender, age, an unhealthy tooth, caries with pulp involvement, pulpotomy, pulpectomy, and the absence of a restoration were associated with a higher occurrence of inflammatory root resorption in primary molars. PMID:22790498

Vieira-Andrade, Raquel Gonçalves; Drumond, Clarissa Lopes; Alves, Laura Pereira Azevedo; Marques, Leandro Silva; Ramos-Jorge, Maria Letícia

2012-01-01

178

DNA Templated Synthesis (DTS) -Nature's effective molarity based approach-  

E-print Network

DNA Templated Synthesis (DTS) -Nature's effective molarity based approach- Organic Seminar 27th May Translation DNA RNA Protein Replication mRNA tRNA Nucleic acid templated synthesis plays a important role X Y -CTGCC TGG -GACGGCACCAT CA X-Y DNA-templated synthesis (DTS) have the ability to direct

Katsumoto, Shingo

179

Accidental displacement of impacted maxillary third molar: a case report  

Microsoft Academic Search

An unusual case of an impacted right maxillary third molar that was accidentally displaced into the maxillary sinus during exodontia and was surgically retrieved almost 2 years later is described. The tooth was removed under general anesthesia, after maxillary sinus exposure through Caldwell-Luc approach. Postoperative recovery was uneventful. Six months after the retrieval surgery, the maxillary sinus was completely healed

Cassio Edvard Sverzut; Alexandre Elias Trivellato; Luiz Marcel de Figueiredo; Emanuela Prado Ferraz; Alexander Tadeu Sverzut

2005-01-01

180

Molar mass of dry air in mass metrology  

Microsoft Academic Search

Since 1980, the different national metrology institutes use the same procedure and formula for air density determination. The formula employed assumes some hypotheses on the composition of dry air and is expressed in terms of its molar mass and the four environmental parameters: air pressure, air temperature and concentrations of carbon dioxide and water vapour. In this formula (known as

N. Khélifa; M. Lecollinet; M. Himbert

2007-01-01

181

A permanent mandibular second molar with seven root canal systems.  

PubMed

This case report illustrates the nonsurgical endodontic management of a seven-canaled mandibular second molar. The root canal configuration presented as four mesial and three distal canals. Identification of the canal system was made with the aid of magnification, ultrasonics, and multiple angulated radiographs. Postoperative examination at 18 months showed a clinically asymptomatic tooth with resolution of the periapical pathology. PMID:24634902

Kottoor, Jojo; Paul, Kuriachan Kottanathu; Mathew, Joy; George, Saira; Mathew, Jain; Roy, Arun

2014-05-01

182

Low-temperature heat capacities and standard molar enthalpy of formation of pyridine-2,6-dicarboxylic acid  

NASA Astrophysics Data System (ADS)

This paper reports that the low-temperature heat capacities of pyridine-2,6-dicarboxylic acid were measured by a precision automatic calorimeter over a temperature range from 78 K to 380 K. A polynomial equation of heat capacities as a function of temperature was fitted by the least-squares method. Based on the fitted polynomial, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated and tabulated at intervals of 5 K. The constant-volume energy of combustion of the compound was determined by means of a precision rotating-bomb combustion calorimeter. The standard molar enthalpy of combustion of the compound was derived from the constant-volume energy of combustion. The standard molar enthalpy of formation of the compound was calculated from a combination of the datum of the standard molar enthalpy of combustion of the compound with other auxiliary thermodynamic quantities through a Hess thermochemical cycle.

Yang, Wei-Wei; Di, You-Ying; Kong, Yu-Xia; Tan, Zhi-Cheng

2010-06-01

183

American Mineralogist, Volume 93, pages 10051013, 2008 0003-004X/08/00071005$05.00/DOI: 10.2138/am.2008.2773 1005  

E-print Network

abundance in the Earth's lower crust and upper mantle, clinopyroxenes have been the subject of sev- eral to pressure-volume data for all samples. The following relationship between bulk modulus and molar fraction of jadeite is observed: KT0 = 108.7(2) (GPa) + 0.191(9) Ã? [% molar Jd] + 0.0006(1) Ã? [% molar Jd]2 The bulk

Thompson, Richard Maxwell

184

Corticotomy-assisted molar protraction with the aid of temporary anchorage device.  

PubMed

This case report describes the interdisciplinary management of a 58-year-old woman who was missing lower first molars and supraerupted maxillary first molars. The treatment plan included intrusion of the upper first molars and corticotomy-assisted mandibular second molar protraction with the aid of temporary anchorage devices. Miniscrews were effective in intrusion of the maxillary first molars and protraction of the lower second molars. Although good functional outcome was achieved in 41 months, the corticotomy-assisted procedure did not significantly reduce the treatment time. PMID:23834274

Uribe, Flavio; Janakiraman, Nandakumar; Fattal, Amine N; Schincaglia, Gian Pietro; Nanda, Ravindra

2013-11-01

185

A new mammal skull from the Lower Cretaceous of China with implications for the evolution of obtuse-angled molars and 'amphilestid' eutriconodonts  

PubMed Central

We report the discovery of Juchilestes liaoningensis, a new genus and species of eutriconodont mammal from the Lujiatun Site of the Lower Cretaceous Yixian Formation (123.2 ± 1.0 Ma; Lower Aptian). The holotype preserves a partial skull and full dentition. Among eutriconodonts, its lower dentition is similar to taxa formerly assigned to the paraphyletic group of ‘amphilestids’. Some have considered ‘amphilestid’ molars to represent the structural intermediate between the lower molars of the ‘triconodont’ pattern of cusps in alignment and the fully triangulate and more derived therian molars. However, ‘amphilestid’ taxa were previously represented only by the lower dentition. Our study reveals, for the first time, the upper dentition and skull structure of an ‘amphilestid’, and shows that at least some eutriconodonts have an obtuse-angled cusp pattern on molars in middle positions of the long molar series. Its petrosal is similar to those of other eutriconodonts and spalacotheroid ‘symmetrodonts’. Our phylogenetic analyses suggest that (i) Juchilestes is most closely related to the Early Cretaceous Hakusanodon from Japan, in the same Eastern Asiatic geographic region; (ii) ‘amphilestids’ are not monophyletic; and (iii) eutriconodonts might not be a monophyletic group, although this hypothesis must be further tested. PMID:19726475

Gao, Chun-Ling; Wilson, Gregory P.; Luo, Zhe-Xi; Maga, A. Murat; Meng, Qingjin; Wang, Xuri

2010-01-01

186

Thermal correction to the molar polarizability of a Boltzmann gas  

SciTech Connect

Metrology in atomic physics has been crucial for a number of advanced determinations of fundamental constants. In addition to very precise frequency measurements, the molar polarizability of an atomic gas has recently also been measured very accurately. Part of the motivation for the measurements is due to ongoing efforts to redefine the International System of Units (SI), for which an accurate value of the Boltzmann constant is needed. Here we calculate the dominant shift of the molar polarizability in an atomic gas due to thermal effects. It is given by the relativistic correction to the dipole interaction, which emerges when the probing electric field is Lorentz transformed into the rest frame of the atoms that undergo thermal motion. While this effect is small when compared to currently available experimental accuracy, the relativistic correction to the dipole interaction is much larger than the thermal shift of the polarizability induced by blackbody radiation.

Jentschura, U. D. [Department of Physics, Missouri University of Science and Technology, Rolla, Missouri 65409-0640 (United States); Puchalski, M. [Department of Physics, Missouri University of Science and Technology, Rolla, Missouri 65409-0640 (United States); Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, PL-60-780 Poznan (Poland); Mohr, P. J. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8420 (United States)

2011-12-15

187

Radicular Cyst in Deciduous Maxillary Molars: A Rarity  

PubMed Central

Radicular cyst arising from deciduous teeth is exceedingly rare accounting for <1% of all radicular cysts. A total of 122 cases have been reported to date in the English language literature. We present a rare case of a radicular cyst associated with a decayed deciduous maxillary molar tooth without any history of prior pulp therapy. Our aim is to emphasize the recognition of inflammatory radicular lesions associated with deciduous teeth which may adversely impact underlying permanent successor. PMID:20237985

Shetty, Shibani; Rekha, K.

2009-01-01

188

Five Canalled and Three-Rooted Primary Second Mandibular Molar  

PubMed Central

A thorough knowledge of root canal anatomy and its variation is necessary for successful completion of root canal procedures. Morphological variations such as additional root canals in human deciduous dentition are rare. A mandibular second primary molar with more than four canals is an interesting example of anatomic variations, especially when three of these canals are located in the distal root. This case shows a rare anatomic configuration and points out the importance of looking for additional canals. PMID:25147744

Selvakumar, Haridoss; Kavitha, Swaminathan; Bharathan, Rajendran; Varghese, Jacob Sam

2014-01-01

189

Extrusion of impacted mandibular second molar using removable appliance  

PubMed Central

The purpose of this article is to review the principles of case management of impacted mandibular molars and to illustrate their potential to respond well to treatment. Although the scope of treatment may be influenced by the patient's age, past dental history, severity of impaction, dentoalveolar development, and root form, the case reports demonstrate the inherent potential for good treatment outcome even in the most unfavorable circumstances.

Karthikeyan, M. K.; Prabhakar, Ramachandran; Saravanan, R.; Vikram, N. Raj; Kumar, R. Vinoth; Prasath, R. Eshwara

2014-01-01

190

Developmental regulations of Perp in mice molar morphogenesis.  

PubMed

Teraspanin transmembrane protein, Perp (P53 apoptosis effector related to PMP22), which is found in the plasma membrane as a component of the desmosome, is reported to be involved in the morphogenesis of the epithelium and the enamel formation of the incisor. However, its expression pattern and signaling regulation during molar development have not been elucidated in detail. We have examined the precise expression patterns of Perp in developing lower molars and employed the knock-down of Perp by antisense oligodeoxynucleotide treatment during in vitro organ cultivation at embryonic day 13 to define the precise developmental function of Perp. Perp was expressed mainly in the dental lamina and stellate reticulum regions at the bud and cap stages. After Perp knock-down, the tooth germ showed disruption of the dental lamina and stellate reticulum with altered apoptosis and proliferation. The changed expression levels of related signaling molecules from the enamel knot and desmosome were evaluated by real-time quantitative polymerase chain reaction. A renal capsule transplantation method was employed to examine the effects of Perp knock-down on molar crown development. Ultrastructural observations revealed that enamel was deposited more densely in an irregular pattern in the cusp region, and that dentin was hypo-mineralized after Perp knock-down at the cap stage. Thus, Perp might play important roles in the formation and integration of stellate reticulum, dental lamina structure and enamel formation through signaling interactions with the enamel knot and desmosome-related signaling molecules at the cap stage of lower molar development. PMID:24865245

Neupane, Sanjiv; Sohn, Wern-Joo; Rijal, Girdhari; Lee, Ye-Ji; Lee, Sanggyu; Yamamoto, Hitoshi; An, Chang-Hyeon; Cho, Sung-Won; Lee, Youngkyun; Shin, Hong-In; Kwon, Tae-Yub; Kim, Jae-Young

2014-10-01

191

An Odor Interaction Model of Binary Odorant Mixtures by a Partial Differential Equation Method  

PubMed Central

A novel odor interaction model was proposed for binary mixtures of benzene and substituted benzenes by a partial differential equation (PDE) method. Based on the measurement method (tangent-intercept method) of partial molar volume, original parameters of corresponding formulas were reasonably displaced by perceptual measures. By these substitutions, it was possible to relate a mixture's odor intensity to the individual odorant's relative odor activity value (OAV). Several binary mixtures of benzene and substituted benzenes were respectively tested to establish the PDE models. The obtained results showed that the PDE model provided an easily interpretable method relating individual components to their joint odor intensity. Besides, both predictive performance and feasibility of the PDE model were proved well through a series of odor intensity matching tests. If combining the PDE model with portable gas detectors or on-line monitoring systems, olfactory evaluation of odor intensity will be achieved by instruments instead of odor assessors. Many disadvantages (e.g., expense on a fixed number of odor assessors) also will be successfully avoided. Thus, the PDE model is predicted to be helpful to the monitoring and management of odor pollutions. PMID:25010698

Yan, Luchun; Liu, Jiemin; Wang, Guihua; Wu, Chuandong

2014-01-01

192

Recurrent hydatidiform mole: A case report of six consecutive molar pregnancies complicated by choriocarcinoma, and review of the literature  

PubMed Central

Hydatidiform mole (HM) is the most common form of gestational trophoblastic neoplasia. Recurrence of HM is extremely rare. Here, we report the case of a patient with six consecutive partial HMs without normal pregnancy. A 42-year-old lady who was referred to us at King Fahad Hospital of the University, Al Khobar, initially as a case of 26-year-old with persistent trophoblastic disease after three recurrent molar pregnancies that were confirmed histologically in the referring hospital. She underwent evacuation and curettage and was followed up by serial ?-human chorionic gonadotropin levels, and did not require chemotherapy. She then had three more molar pregnancies in 1995, 1996, and 2004; all molar pregnancies were evacuated by suction curettage at her base hospital, but in the last event, she complained of shortness of breath and abdominal pain. Diagnostic workup in our hospital confirmed choriocarcinoma, for which she received multiple regimen chemotherapy and was cured. Unfortunately, she lately presented with symptoms suggestive of premature menopause. PMID:22175045

Al-Ghamdi, Ahlam A.

2011-01-01

193

Quality of life following third molar removal under conscious sedation  

PubMed Central

Aim: The aim of this study was to assess quality of life (QoL) and degree of satisfaction among outpatients subjected to surgical extraction of all four third molars under conscious sedation. A second objective was to describe the evolution of self-reported pain measured in a visual analogue scale (VAS) in the 7 days after extraction. Study design: Fifty patients received a questionnaire assessing social isolation, working isolation, eating and speaking ability, diet modifications, sleep impairment, changes in physical appearance, discomfort at suture removal and overall satisfaction at days 4 and 7 after surgery. Pain was recorded by patients on a 100-mm pain visual analogue scale (VAS) every day after extraction until day 7. Results: Thirty-nine patients fulfilled correctly the questionnaire. Postoperative pain values suffered small fluctuations until day 5 (range: 23 to 33 mm in a 100-mm VAS), when dicreased significantly. A positive association was observed between difficult ranked surgeries and higher postoperative pain levels. The average number of days for which the patient stopped working was 4.9. Conclusion: The removal of all third molars in a single appointment causes an important deterioration of the patient’s QoL during the first postoperative week, especially due to local pain and eating discomfort. Key words:Third molar removal, quality of life, sedation. PMID:22926461

Sancho-Puchades, Manuel; Berini-Aytes, Leonardo; Gay-Escoda, Cosme

2012-01-01

194

Rescue surgery (surgical repositioning) of impacted lower second molars.  

PubMed

The impaction of lower second molars, given that its incidence is 0.03 to 0.21%, is a rare complication in tooth eruption. It has been detected more often in unilateral form than bilateral and is more common in the mandible than in the maxillary. It has a slight predilection for males, and mesial inclination is more usual. A wide variety of therapeutic approaches have been published, basically referring to surgical techniques, independent or complemented by means of orthodontic technical aids, with the aim of placing the tooth in the correct position, and which are encompassed under the concept of surgical rescue. In cases resolved with repositioning of an impacted tooth, prophylactic root extraction has been proposed as obligatory. We present a case of a 12 and a half year old patient referred to the University of Seville due to non-eruption of the left lower second molar. The patient was referred by her orthodontist, who detected the impaction before starting orthodontic treatment. The orthodontist requested that, if it was possible, we did not extract the root of the third molar, because its eruption would be feasible in the future (there would be sufficient space in the arch). The spaces available were measured and we decided to attempt the repositioning of the impacted tooth without extracting the root of the wisdom tooth, which was carried out successfully. PMID:16264380

García-Calderón, Manuel; Torres-Lagares, Daniel; González-Martín, Maribel; Gutiérrez-Pérez, José Luis

2005-01-01

195

Intranasal atomized dexmedetomidine for sedation during third molar extraction.  

PubMed

The purpose of this study was to evaluate the intranasal use of 1.5 ?g/kg atomized dexmedetomidine for sedation in patients undergoing mandibular third molar removal. Eighteen patients underwent third molar removal in two surgical sessions. Patients were randomly assigned to receive intranasal water (placebo group) or 1.5 ?g/kg atomized dexmedetomidine (group D) at the first session. The alternate regimen was used during the second session. Local anaesthesia was injected 30 min after placebo/sedative administration. Pain from local anaesthesia infiltration was rated on a scale from zero (no pain) to 10 (worst pain imaginable). Sedation status was measured every 10 min by a blinded observer with a modified Observer's Assessment of Alertness/Sedation (OAA/S) scale and the bispectral index (BIS). Adverse reactions and analgesic consumption were recorded. Sedation values in group D were significantly different from placebo at 20-30 min, peaked at 40-50 min, and returned to placebo levels at 70-80 min after intranasal drug administration. Group D displayed decreased heart rate and systolic blood pressure, but the decreases did not exceed 20% of the baseline values. Intranasal administration of 1.5 ?g/kg atomized dexmedetomidine is effective, convenient, and safe as a sedative for patients undergoing third molar extraction. PMID:23497981

Nooh, N; Sheta, S A; Abdullah, W A; Abdelhalim, A A

2013-07-01

196

Molar Macrowear Reveals Neanderthal Eco-Geographic Dietary Variation  

PubMed Central

Neanderthal diets are reported to be based mainly on the consumption of large and medium sized herbivores, while the exploitation of other food types including plants has also been demonstrated. Though some studies conclude that early Homo sapiens were active hunters, the analyses of faunal assemblages, stone tool technologies and stable isotopic studies indicate that they exploited broader dietary resources than Neanderthals. Whereas previous studies assume taxon-specific dietary specializations, we suggest here that the diet of both Neanderthals and early Homo sapiens is determined by ecological conditions. We analyzed molar wear patterns using occlusal fingerprint analysis derived from optical 3D topometry. Molar macrowear accumulates during the lifespan of an individual and thus reflects diet over long periods. Neanderthal and early Homo sapiens maxillary molar macrowear indicates strong eco-geographic dietary variation independent of taxonomic affinities. Based on comparisons with modern hunter-gatherer populations with known diets, Neanderthals as well as early Homo sapiens show high dietary variability in Mediterranean evergreen habitats but a more restricted diet in upper latitude steppe/coniferous forest environments, suggesting a significant consumption of high protein meat resources. PMID:21445243

Fiorenza, Luca; Benazzi, Stefano; Tausch, Jeremy; Kullmer, Ottmar; Bromage, Timothy G.; Schrenk, Friedemann

2011-01-01

197

Molar macrowear reveals Neanderthal eco-geographic dietary variation.  

PubMed

Neanderthal diets are reported to be based mainly on the consumption of large and medium sized herbivores, while the exploitation of other food types including plants has also been demonstrated. Though some studies conclude that early Homo sapiens were active hunters, the analyses of faunal assemblages, stone tool technologies and stable isotopic studies indicate that they exploited broader dietary resources than Neanderthals. Whereas previous studies assume taxon-specific dietary specializations, we suggest here that the diet of both Neanderthals and early Homo sapiens is determined by ecological conditions. We analyzed molar wear patterns using occlusal fingerprint analysis derived from optical 3D topometry. Molar macrowear accumulates during the lifespan of an individual and thus reflects diet over long periods. Neanderthal and early Homo sapiens maxillary molar macrowear indicates strong eco-geographic dietary variation independent of taxonomic affinities. Based on comparisons with modern hunter-gatherer populations with known diets, Neanderthals as well as early Homo sapiens show high dietary variability in Mediterranean evergreen habitats but a more restricted diet in upper latitude steppe/coniferous forest environments, suggesting a significant consumption of high protein meat resources. PMID:21445243

Fiorenza, Luca; Benazzi, Stefano; Tausch, Jeremy; Kullmer, Ottmar; Bromage, Timothy G; Schrenk, Friedemann

2011-01-01

198

Representations of partial derivatives in thermodynamics  

NASA Astrophysics Data System (ADS)

One of the mathematical objects that students become familiar with in thermodynamics, often for the first time, is the partial derivative of a multivariable function. The symbolic representation of a partial derivative and related quantities present difficulties for students in both mathematical and physical contexts, most notably what it means to keep one or more variables fixed while taking the derivative with respect to a different variable. Material properties are themselves written as partial derivatives of various state functions (e.g., compressibility is a partial derivative of volume with respect to pressure). Research in courses at the University of Maine and Oregon State University yields findings related to the many ways that partial derivatives can be represented and interpreted in thermodynamics. Research has informed curricular development that elicits many of the difficulties using different representations (e.g., geometric) and different contexts (e.g., connecting partial derivatives to specific experiments).

Thompson, John R.; Manogue, Corinne A.; Roundy, David J.; Mountcastle, Donald B.

2012-02-01

199

GENERAL: Low-temperature heat capacities and standard molar enthalpy of formation of N-methylnorephedrine C11H17NO(s)  

NASA Astrophysics Data System (ADS)

This paper reports that low-temperature heat capacities of N-methylnorephedrine C11H17NO(s) have been measured by a precision automated adiabatic calorimeter over the temperature range from T = 78 K to T = 400K. A solid to liquid phase transition of the compound was found in the heat capacity curve in the temperature range of T = 342-364 K. The peak temperature, molar enthalpy and entropy of fusion of the substance were determined. The experimental values of the molar heat capacities in the temperature regions of T = 78-342 K and T = 364-400 K were fitted to two polynomial equations of heat capacities with the reduced temperatures by least squares method. The smoothed molar heat capacities and thermodynamic functions of N-methylnorephedrine C11H17NO(s) relative to the standard reference temperature 298.15 K were calculated based on the fitted polynomials and tabulated with an interval of 5 K. The constant-volume energy of combustion of the compound at T = 298.15K was measured by means of an isoperibol precision oxygen-bomb combustion calorimeter. The standard molar enthalpy of combustion of the sample was calculated. The standard molar enthalpy of formation of the compound was determined from the combustion enthalpy and other auxiliary thermodynamic data through a Hess thermochemical cycle.

Di, You-Ying; Wang, Da-Qi; Shi, Quan; Tan, Zhi-Cheng

2008-08-01

200

Partial ceramic crowns. Influence of preparation design and luting material on margin integrity—a scanning electron microscopic study  

Microsoft Academic Search

This in vitro study examines the effects of three preparation designs and different luting agents on the marginal integrity of partial ceramic crowns. One hundred forty-four extracted human molars were prepared according to the following preparation designs: A. Coverage of functional cusps, B. Horizontal reduction of functional cusps and C. Complete reduction of functional cusps. Partial ceramic crowns (Vita Mark

Marianne Federlin; C. Sipos; K.-A. Hiller; B. Thonemann; G. Schmalz

2005-01-01

201

Surgical extraction of deeply horizontally impacted mandibular second and third molars.  

PubMed

The presence of deeply horizontally impacted lower second and third molars is unusual. The arrested eruption of the lower second and third molars can determine disturbances of mastication and aesthetics. Moreover, an increased risk of caries in the distal side of the first lower molar is possible. Different therapeutic approaches could be proposed for second and third molar impaction and malposition. In this article, we report the management and the outcome of the surgical treatment of a patient with impacted mandibular second and third molars. PMID:20186075

Boffano, Paolo; Gallesio, Cesare; Bianchi, Francesca; Roccia, Fabio

2010-03-01

202

Mandibular third molar development after mantle radiation in long-term survivors of childhood Hodgkin's disease  

SciTech Connect

Sequential panoramic radiographs were assessed for mandibular third molar development in 47 long-term survivors of childhood Hodgkin's disease after treatment with 37 Gy mantle field radiation. To make a comparison, panoramic radiographs of 149 healthy, nonirradiated children were reviewed for the presence of mandibular third molars. In children between the ages of 7 and 12 years, bilateral agenesis of mandibular third molars was more frequent in patients who had been treated with mantle radiation than in nonirradiated patients. Unilateral agenesis, crown hypoplasia, and root growth impairment of mandibular third molars were also found. Similar, apparent, radiation-induced developmental anomalies were noted in maxillary third molars of the irradiated patients.

McGinnis, J.P. Jr.; Hopkins, K.P.; Thompson, E.I.; Hustu, H.O.

1987-05-01

203

Restoration of Endodontically Treated Molars Using All Ceramic Endocrowns  

PubMed Central

Clinical success of endodontically treated posterior teeth is determined by the postendodontic restoration. Several options have been proposed to restore endodontically treated teeth. Endocrowns represent a conservative and esthetic restorative alternative to full coverage crowns. The preparation consists of a circular equigingival butt-joint margin and central retention cavity into the entire pulp chamber constructing both the crown and the core as a single unit. The case reports discussed here are moderately damaged endodontically treated molars restored using all ceramic endocrowns fabricated using two different systems, namely, CAD/CAM and pressed ceramic. PMID:24455318

Carlos, Roopak Bose; Thomas Nainan, Mohan; Pradhan, Shamina; Roshni Sharma; Benjamin, Shiny; Rose, Rajani

2013-01-01

204

[Cheek swelling after surgical removal of third molar].  

PubMed

A 55-years-old man visited his family doctor because of a one-day existing, not painful, right-sided swelling of the cheek. It appeared to be a subcutaneous emphysema, caused at an attempt to remove mandibular third molar roots, using a water- and air-cooled air rotor. Rare potential se?elae resulting from subcutaneous emphysema are venous air embolism, airway obstruction because of neck swelling, pneumomediastinum, and mediastinitis. Using air-cooled instruments in surgical orofacial treatments should be avoided because of the possible atrogenic life-threatening complications. PMID:16566402

van Essen, G A; de Baat, C

2006-03-01

205

Kinetics of the Free-Radical Polymerization of Isobornyl Methacrylate in the Presence of Polyisobutylenes of Different Molar Masses  

E-print Network

The effect of a linear polymer dissolved in a reactive monomer on the kinetics of free-radical polymerization is studied. The selected system was a solution of polyisobutylene (PIB) in isobornyl methacrylate (IBoMA). Ternary phase diagrams of PIB, IBoMA and poly(isobornyl methacrylate) (PIBoMA) were built at 80C. They were shifted to lower conversions when increasing the molar mass of PIB. Different PIBs exhibiting CPC at advanced conversions were selected for the kinetic study performed employing differential scanning calorimetry (DSC) at 80C. A simple kinetic model for free-radical polymerizations describing the relevant termination rate constant in terms of the free-volume theory, provided a consistent fitting of the polymerization rates in the conversion range where the solution remained homogeneous. Increasing the molar mass of PIB led to an increase in polymerization rate due to the decrease in free volume and the corresponding decrease of the termination rate. Increasing the amount of a particular PIB in the initial formulation led to a less marked gel effect, explained by the smaller relative variation of free volume with conversion. The dimensionless free volume of PIB obtained from the kinetic model was found to increase with the volume concentration of chain ends, as expected. Under conditions where phase separation took place at very low conversions, the overall polymerization rate exhibited the presence of two maxima (gel effects), representing the polymerization in two different phases. The first maximum was associated to the polymerization taking place in the phase lean in PIB and the second maximum was associated to the polymerization of the monomer that was initially fractionated with PIB.

Ezequiel R. Soule; Julio Borrajo; Roberto J. J. Williams

2013-11-21

206

The Prevalence of Bilateral Three-Rooted Mandibular First Molar in Indian Population  

PubMed Central

Introduction The purpose of the present study was to evaluate the prevalence of bilateral three-rooted mandibular first and second molars in Indian population. Materials and Methods A total of 215 patients were screened bilaterally for mandibular first and second molar and 430 samples of periapical radiographs were obtained. The gender, symmetry, and prevalence of three-rooted mandibular first and second molars were recorded. The correlation between left and right side occurrences and distribution were recorded and analysed using Z-test. Results The results showed that 33 teeth had three-rooted mandibular first molars, 16 male and 17 female (P=0.442). Overall, 21 teeth of right jaw and 12 teeth of left jaw (P=0.103) showed presence of an extra-root. The prevalence of three-rooted mandibular first molars was 7.67% and second molar was 0.23%. The bilateral frequency distribution was 3.72% for the first molar. There was no statistically significant difference between right side and left side mandibular molars. Also, gender did not show a significant relationship with this variant. Conclusion The endodontic treatments of first mandibular molars require a careful clinical approach in Indian population as a high racial prevalence of 7.67% three-rooted molars was found. However, in the same population, 0.23% mandibular second molars had three roots. PMID:23922569

Karale, Rupali; Chikkamallaiah, Champa; Hegde, Jayshree; Aswathanarayana, Srirekha; Santhosh, Lekha; Bashetty, Kusum; Rajanna Susheela, Shwetha; Panchajanya, Srinivas

2013-01-01

207

Compensation trends of the angulation of first molars: retrospective study of 1?403 malocclusion cases.  

PubMed

We investigated the compensatory trends of mesiodistal angulation of first molars in malocclusion cases. We compared differences in the angulation of first molars in different developmental stages, malocclusion classifications and skeletal patterns. The medical records and lateral cephalogrammes of 1?403 malocclusion cases taken before treatment were measured to evaluate compensation of molar angulation in relation to the skeletal jaw. The cases were stratified by age, Angle classification and skeletal patterns. Differences in the mesiodistal angulation of the first molars were compared among the stratifications. We observed three main phenomena. First, angulation of the upper first molar varied significantly with age and tipped most distally in cases aged <12 years and least distally in cases aged >16 years. The lower first molar did not show such differences. Second, in Angle Class II or skeletal Class II cases, the upper first molar was the most distally tipped, the lower first molar was the most mesially tipped, and opposite angulation compensation was observed in Class III cases. Third, in high-angle cases, the upper and lower first molars were the most distally tipped, and opposite angulation compensation was observed in low-angle cases. These data suggest that the angulation of the molars compensated for various growth patterns and malocclusion types. Hence, awareness of molar angulation compensation would help to adjust occlusal relationships, control anchorage and increase the chances of long-term stability. PMID:24699185

Su, Hong; Han, Bing; Li, Sa; Na, Bin; Ma, Wen; Xu, Tian-Min

2014-09-01

208

Compensation trends of the angulation of first molars: retrospective study of 1 403 malocclusion cases  

PubMed Central

We investigated the compensatory trends of mesiodistal angulation of first molars in malocclusion cases. We compared differences in the angulation of first molars in different developmental stages, malocclusion classifications and skeletal patterns. The medical records and lateral cephalogrammes of 1?403 malocclusion cases taken before treatment were measured to evaluate compensation of molar angulation in relation to the skeletal jaw. The cases were stratified by age, Angle classification and skeletal patterns. Differences in the mesiodistal angulation of the first molars were compared among the stratifications. We observed three main phenomena. First, angulation of the upper first molar varied significantly with age and tipped most distally in cases aged <12 years and least distally in cases aged >16 years. The lower first molar did not show such differences. Second, in Angle Class II or skeletal Class II cases, the upper first molar was the most distally tipped, the lower first molar was the most mesially tipped, and opposite angulation compensation was observed in Class III cases. Third, in high-angle cases, the upper and lower first molars were the most distally tipped, and opposite angulation compensation was observed in low-angle cases. These data suggest that the angulation of the molars compensated for various growth patterns and malocclusion types. Hence, awareness of molar angulation compensation would help to adjust occlusal relationships, control anchorage and increase the chances of long-term stability. PMID:24699185

Su, Hong; Han, Bing; Li, Sa; Na, Bin; Ma, Wen; Xu, Tian-Min

2014-01-01

209

Partial tooth gear bearings  

NASA Technical Reports Server (NTRS)

A partial gear bearing including an upper half, comprising peak partial teeth, and a lower, or bottom, half, comprising valley partial teeth. The upper half also has an integrated roller section between each of the peak partial teeth with a radius equal to the gear pitch radius of the radially outwardly extending peak partial teeth. Conversely, the lower half has an integrated roller section between each of the valley half teeth with a radius also equal to the gear pitch radius of the peak partial teeth. The valley partial teeth extend radially inwardly from its roller section. The peak and valley partial teeth are exactly out of phase with each other, as are the roller sections of the upper and lower halves. Essentially, the end roller bearing of the typical gear bearing has been integrated into the normal gear tooth pattern.

Vranish, John M. (Inventor)

2010-01-01

210

Densities and molar volumes of refined sodium oxide-containing slag melts  

Microsoft Academic Search

The refined slag mixtures used in electric-arc furnaces and ladle?furnace units usually contain up to 20? 30% fluorite. It is important to replace fluorite, which is employed as a thinning agent for highly basic refining slags, especially from an ecological viewpoint, since CaF 2 decomposes in the zone of electric arcs to yield anhydrous hydrogen fluoride. To form free-running refining

I. A. Magidson; A. V. Basov; N. A. Smirnov; M. V. Ezova

2007-01-01

211

A method for estimating both the solubility parameters and molar volumes of liquids  

NASA Technical Reports Server (NTRS)

Development of an indirect method of estimating the solubility parameter of high molecular weight polymers. The proposed method of estimating the solubility parameter, like Small's method, is based on group additive constants, but is believed to be superior to Small's method for two reasons: (1) the contribution of a much larger number of functional groups have been evaluated, and (2) the method requires only a knowledge of structural formula of the compound.

Fedors, R. F.

1974-01-01

212

Nanoparticle counting: towards accurate determination of the molar concentration.  

PubMed

Innovations in nanotechnology have brought tremendous opportunities for the advancement of many research frontiers, ranging from electronics, photonics, energy, to medicine. To maximize the benefits of nano-scaled materials in different devices and systems, precise control of their concentration is a prerequisite. While concentrations of nanoparticles have been provided in other forms (e.g., mass), accurate determination of molar concentration, arguably the most useful one for chemical reactions and applications, has been a major challenge (especially for nanoparticles smaller than 30 nm). Towards this significant yet chronic problem, a variety of strategies are currently under development. Most of these strategies are applicable to a specialized group of nanoparticles due to their restrictions on the composition and size range of nanoparticles. As research and uses of nanomaterials are being explored in an unprecedented speed, it is necessary to develop universal strategies that are easy to use and are compatible with nanoparticles of different sizes, compositions, and shapes. This review outlines the theories and applications of current strategies to measure nanoparticle molar concentration, discusses the advantages and limitations of these methods, and provides insights into future directions. PMID:25099190

Shang, Jing; Gao, Xiaohu

2014-11-01

213

Study of molar response of dextrans in electrochemical detection.  

PubMed

In this work, a methodological approach is reported, aimed at assessing the electrochemical response of some model gluco-oligosaccharides (dextrans). Such strategy is based on the complementary use of both anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) and capillary zone electrophoresis coupled with UV detection (CZE-UV). Unlike HPAEC-PAD, CZE-UV required derivatization with a chromophoric dye (i.e., 8-aminonaphtalene-1,3,6-trisulphonic acid, ANTS) to enhance UV response and separation selectivity. From the comparison between chromophore response and PAD signal, the reliability of HPAEC-PAD for quantitative evaluation of dextran mixtures containing mainly oligomers with polymerization degree (DP) up to 18 could be proved, due to the fairly constant molar response. For higher DPs (up to 41), a maximum in the trend of the molar responses was observed followed by a steep decrease for DPs higher than about 30-35; indeed, an underestimation of weight-average molecular weight of dextran mixtures containing such oligomers was noticed. PMID:17188282

Abballe, Franco; Toppazzini, Mila; Campa, Cristiana; Uggeri, Fulvio; Paoletti, Sergio

2007-05-11

214

Nanomechanical Behavior of Human Molars Soaked in Slight Acid Solutions  

NASA Astrophysics Data System (ADS)

This paper studied the mechanical and chemical properties of hydroxyl apatite (HA) crystal structure in the teeth when human molars were soaked in slight acid solution. First, we soaked the ground and polished molars respectively in the liquor of 30 wt.% H2CO3 and the liquor of 30 wt.% H2O2 for 10, 20, or 60 minutes. Next, we used a nanoindenter to measure the hardness and Young's modulus. Finally, we used a scanning electron microscope (SEM) coupled with energy dispersive spectroscopy (EDS) to analyze the variation of Ca, P and Na in teeth, a high resolution transmitting electron microscope (HRTEM) to observe the arrangement of crystallization phase of HA, and X-ray diffraction (XRD) to analyze the crystallinity of the hexagonal phase of HA. The results showed that the demineralization phenomenon of the calcium-phosphorous compound in teeth made the teeth reduce sharply in hardness and Young's modulus after they were soaked in the two slight acid solutions for 10 minutes, but the re-mineralization phenomenon made the hardness and Young's modulus ascend gradually when the time lasted longer. With the same period of time, the teeth soaked in H2CO3 were lower in the hardness and Young's modulus than that in H2O2.

Fang, Te-Hua; Chang, Win-Jin; Kang, Shao-Hui; Chu, Chia-Chun

215

VOLUME 78, NUMBER 5 P H Y S I C A L R E V I E W L E T T E R S 3 FEBRUARY 1997 Fractal Model for Coarse-Grained Nonlinear Partial Differential Equations  

E-print Network

spatial filter with characteristic scale D h ø D ø L , yields a coarse-grained variable ~a GDa. Once, unless the dynami- cal equations are linear, the success of such a program de- pends largely upon. In this Letter, we describe an ap- proach that uses fractals to close coarse-grained, non- linear partial

Scotti, Alberto

216

The average free volume model for liquids  

E-print Network

In this work, the molar volume thermal expansion coefficient of 59 room temperature ionic liquids is compared with their van der Waals volume Vw. Regular correlation can be discerned between the two quantities. An average free volume model, that considers the particles as hard core with attractive force, is proposed to explain the correlation in this study. A combination between free volume and Lennard-Jones potential is applied to explain the physical phenomena of liquids. Some typical simple liquids (inorganic, organic, metallic and salt) are introduced to verify this hypothesis. Good agreement from the theory prediction and experimental data can be obtained.

Yu, Yang

2014-01-01

217

The average free volume model for liquids  

E-print Network

In this work, the molar volume thermal expansion coefficient of 59 room temperature ionic liquids is compared with their van der Waals volume Vw. Regular correlation can be discerned between the two quantities. An average free volume model, that considers the particles as hard core with attractive force, is proposed to explain the correlation in this study. A combination between free volume and Lennard-Jones potential is applied to explain the physical phenomena of liquids. Some typical simple liquids (inorganic, organic, metallic and salt) are introduced to verify this hypothesis. Good agreement from the theory prediction and experimental data can be obtained.

Yang Yu; Reinhard Krause-Rehberg

2014-04-02

218

Lattice potential energy and standard molar enthalpy in the formation of 1—dodecylamine hydrobromide (1-C12H25NH3·Br)(s)  

NASA Astrophysics Data System (ADS)

This paper reports that 1-dodecylamine hydrobromide (1-C12H25NH3·Br)(s) has been synthesized using the liquid phase reaction method. The lattice potential energy of the compound 1-C12H25NH3·Br and the ionic volume and radius of the 1-C12H25NH3+ cation are obtained from the crystallographic data and other auxiliary thermodynamic data. The constant-volume energy of combustion of 1-C12H25NH3·Br(s) is measured to be ?cUmo(1-C12H25NH3·Br, s) = -(7369.03±3.28) kJ·mol-1 by means of an RBC-II precision rotating-bomb combustion calorimeter at T = (298.15±0.001) K. The standard molar enthalpy of combustion of the compound is derived to be ?cHmo(1-C12H25NH3·Br, s) = -(7384.52±3.28) kJ·mol-1 from the constant-volume energy of combustion. The standard molar enthalpy of formation of the compound is calculated to be ?fHmo(1-C12H25NH3·Br, s)=-(1317.86±3.67) kJ·mol-1 from the standard molar enthalpy of combustion of the title compound and other auxiliary thermodynamic quantities through a thermochemical cycle.

Liu, Yu-Pu; Di, You-Ying; Dan, Wen-Yan; He, Dong-Hua; Kong, Yu-Xia; Yang, Wei-Wei

2011-02-01

219

Radiographic evaluation of third molar development in 6- to 24-year-olds  

PubMed Central

Purpose This study investigated the developmental stages of third molars in relation to chronological age and compared third molar development according to location and gender. Materials and Methods A retrospective analysis of panoramic radiographs of 2490 patients aged between 6 and 24 years was conducted, and the developmental stages of the third molars were evaluated using the modified Demirjian's classification. The mean age, standard deviation, minimal and maximal age, and percentile distributions were recorded for each stage of development. A Mann-Whitney U test was performed to test the developmental differences in the third molars between the maxillary and mandibular arches and between genders. A linear regression analysis was used for assessing the correlation between the third molar development and chronological age. Results The developmental stages of the third molars were more advanced in the maxillary arch than the mandibular arch. Males reached the developmental stages earlier than females. The average age of the initial mineralization of the third molars was 8.57 years, and the average age at apex closure was 21.96 years. The mean age of crown completion was 14.52 and 15.04 years for the maxillary and the mandibular third molars, respectively. Conclusion The developmental stages of the third molars clearly showed a strong correlation with age. The third molars developed earlier in the upper arch than the lower arch; further, they developed earlier in males than in females. PMID:25279338

Jung, Yun-Hoa

2014-01-01

220

An in vitro morphological investigation of the endodontic spaces of third molars.  

PubMed

Aim of this paper was to investigate the particular anatomic features of the endodontic space of third molars in the general population of Croatia. A total of 106 fully developed third molars (56 maxillar and 50 mandibular) has been analyzed. The respective number of roots and of root canals, the structure of the roots, and the curvature and absolute length of the root-canals were analyzed. In most cases, upper third molars had three roots (83.9%), while most of the lower molars were single rooted (56.0%). Upper third molars had mostly three root canals (75.1%), lower third molars two (90.0%). In both jaws, most third molars had curved canals (60.7% in the upper and 84.0% in the lower jaw). 12.5% of upper third molars had lateral and accessory canals, whereas only 4.0% of the lower third molars were found to have them. The Student t-test showed statistically significant differences (p < 0.05) in the length of the root-canals, mesiobuccal and distobuccal canals being significantly shorter than palatinal canals. The same test showed that in the lower third molars the mesial root canals were significantly longer that the distal ones, although slightly. The results obtained are in compliance with similar results by other authors; however, they tend to show some specific population-related features. PMID:23940986

Cosi?, Jozo; Gali?, Nada; Vodanovi?, Marin; Njemirovskij, Vera; Segovi?, Sanja; Paveli?, Bozidar; Ani?, Ivica

2013-06-01

221

Molarity (Aromic Density) of the Elements as Pure Crystals.  

ERIC Educational Resources Information Center

Provides background information for teachers on the atomic density of the elements as pure crystals. Atomic density is defined as the reciprocal of the atomic volume. Includes atomic-density diagrams which were prepared using the atomic-volume values given by Singman, supplemented by additional values for some allotropes. (JN)

Pauling, Linus; Herman, Zelek S.

1985-01-01

222

Epidemiological study of complete and partial hydatidiform mole in Abu Dhabi: influence age and ethnic group  

Microsoft Academic Search

An unmatched case control study of molar pregnancy was carried out at this hospital between 1978 and 1987 to investigate the influence of maternal age and ethnic group on the incidence of complete and partial hydatidiform mole. The age specific incidence of complete mole was minimal between the ages of 30 and 34 years (relative risk 1), showed a minor

I H Graham; A M Fajardo; R L Richards

1990-01-01

223

Initial Clinical Experience With the Strut-Adjusted Volume Implant (SAVI) Breast Brachytherapy Device for Accelerated Partial-Breast Irradiation (APBI): First 100 Patients With More Than 1 Year of Follow-Up  

SciTech Connect

Purpose: The Strut-Adjusted Volume Implant (SAVI; Cianna Medical, Aliso Viejo, CA) is a multichannel single-entry brachytherapy device designed to allow dose modulation to minimize normal tissue dose while simultaneously maximizing target coverage. This is the first report on the initial 102 patients with nearly 2 years of median follow-up. Methods and Materials: One hundred two patients were treated at two institutions. Data were collected on eligibility and dosimetry and followed for toxicity and recurrence. Results: The median follow-up is 21 months. Overall dosimetry is outstanding (median percent of target volume receiving 90% of the prescription dose was 95.9%, volume of target receiving 150% of the prescription dose was 27.8 mL, and volume of target receiving 200% of the prescription dose was 14.0 cm{sup 3}). No devices were pulled prior to treatment completion. For patients with a skin bridge of less than 7 mm, the maximum median skin dose was 280 cGy (median percent of target volume receiving 90% of the prescription dose was 95.2%, volume of target receiving 150% of the prescription dose was 25.8 cm{sup 3} and volume of target receiving 200% of the prescription dose was 12.7 mL). For patients with both chest wall and skin of less than 7 mm, the maximum median lung dose was 205 cGy with simultaneous skin dose of 272 cGy. The rate of telangiectasia was 1.9%. Grade 1 hyperpigmentation developed in 10 patients (9.8%) and Grade 2 fibrosis in 2 patients (1.9%). There were 2 symptomatic seromas and 2 cases of asymptomatic fat necrosis (1.9%). Of the patients, 27% were not eligible for MammoSite balloon brachytherapy (Hologic, Inc., Marlborough, MA) and 5% were not eligible for any balloon brachytherapy. The recurrence rate was 1%. Conclusions: The SAVI appears to safely allow an increase in eligibility for APBI over balloon brachytherapy or three-dimensional conformal radiation, highlighting the outstanding device flexibility to maximize the target dose and minimize the normal tissue dose. The device was well tolerated by patients.

Yashar, Catheryn M., E-mail: cyashar@ucsd.edu [Department of Radiation Oncology, University of California San Diego, La Jolla, CA (United States); Scanderbeg, Daniel [Department of Radiation Oncology, University of California San Diego, La Jolla, CA (United States); Kuske, Robert [Arizona Breast Cancer Specialists, Phoenix, AZ (United States); Wallace, Anne [Department of Surgery, University of California San Diego, La Jolla, CA (United States); Zannis, Victor [Breast Care Center of the Southwest, Phoenix, AZ (United States); Blair, Sarah [Department of Surgery, University of California San Diego, La Jolla, CA (United States); Grade, Emily; Swenson, Virginia H. [Arizona Oncology Services Foundation, Phoenix, AZ (United States); Quiet, Coral [Arizona Breast Cancer Specialists, Phoenix, AZ (United States)

2011-07-01

224

Rotation of rectangular wire in rectangular molar tubes. Part I.  

PubMed

The degree of angular rotation of rectangular orthodontic wires in rectangular molar tubes was measured using a rotatable mechanical stage on a Unitron metallograph and compared to theoretical data. It was found that square 0.016 inch wire did not bind in 0.018 by 0.022 inch or larger mandrel- or inconel-formed tubes, whereas rotations of 11 to 23 degrees were noted in cast tubes of this dimension. Although 0.016 by 0.022 inch wire did bind in these tubes, the degree of rotation was far greater than expected on the basis of theoretical calculations or clinical expectations. The results indicated that it was unrealistic to expect fine control of a few degrees of torque to occur as expected for delicate clinical control. PMID:6943934

Raphael, E; Sandrik, J L; Klapper, L

1981-08-01

225

[The pendulis appliance: a palatal miniscrew supported molar distalization device].  

PubMed

The maxillary molar distalization is a valuable therapeutic option in some clinical cases. Its biomechanics is challenging and difficult to obtain. Historically, various devices have been described offering successful solutions to this problem such as the Hilgers Pendulum Appliance (1992) and variants linked to mini screws which recently have shown interesting clinical potential. This article presents a new Pendulum variant using a miniscrew, the "pendulis". It follows the original concept (titanium-molybdenum alloy distalization springs and polymethyl-methacrylate pellet) but dental support is replaced by a single palatal miniscrew (median adults, para-median in children) to which the device is fixed by means of a metal welded cap easily positioned and removable by the practitioner. This allows for better control of the oral hygiene and completely controlled extraoral activation. Fabrication steps are described and instruction of use is illustrated with clinical documentation. PMID:25158749

Nappée-Miévilly, Magali; Nappée, François-Joseph; Kerbrat, Jean-Baptiste; Goudot, Patrick

2014-09-01

226

Intra- and interspecific variation in macaque molar enamel thickness.  

PubMed

Enamel thickness has played an important role in studies of primate taxonomy, phylogeny, and functional morphology, although its variation among hominins is poorly understood. Macaques parallel hominins in their widespread geographic distribution, relative range of body sizes, and radiation during the last five million years. To explore enamel thickness variation, we quantified average and relative enamel thickness (AET and RET) in Macaca arctoides, Macaca fascicularis, Macaca fuscata, Macaca mulatta, Macaca nemestrina, and Macaca sylvanus. Enamel area, dentine area, and enamel-dentine junction length were measured from mesial sections of 386 molars scanned with micro-computed tomography, yielding AET and RET indices. Intraspecific sex differences were not found in AET or RET. Macaca fuscata had the highest AET and RET, M. fascicularis showed the lowest AET, and M. arctoides had the lowest RET. The latitudinal distribution of macaque species was associated with AET for these six species. Temperate macaques had thicker molar enamel than did tropical macaques, suggesting that thick enamel may be adaptive in seasonal environments. Additional research is needed to determine if thick enamel in temperate macaques is a response to intensified hard-object feeding, increased abrasion, and/or a broader diet with a greater range of food material properties. The extreme ecological flexibility of macaques may prohibit identification of consistent trends between specific diets and enamel thickness conditions. Such complications of interpretation of ecological variability, dietary diversity, and enamel thickness may similarly apply for fossil Homo species. Am J Phys Anthropol 155:447-459, 2014. © 2014 Wiley Periodicals, Inc. PMID:25146639

Kato, Akiko; Tang, Nancy; Borries, Carola; Papakyrikos, Amanda M; Hinde, Katie; Miller, Ellen; Kunimatsu, Yutaka; Hirasaki, Eishi; Shimizu, Daisuke; Smith, Tanya M

2014-11-01

227

Micro-computed tomography analysis of changes in the periodontal ligament and alveolar bone proper induced by occlusal hypofunction of rat molars  

PubMed Central

Objective To three-dimensionally elucidate the effects of occlusal hypofunction on the periodontal ligament and alveolar bone proper of rat molars by micro-computed tomography (micro-CT). Methods Occlusal function in the molar area was restricted by attaching an anterior bite plate on the maxillary incisors and a metal cap on the mandibular incisors of 5-week-old male Wistar rats for 1 week. The periodontal ligament space and alveolar bone proper around roots of the mandibular first molar were assessed by histology and micro-CT. Results The periodontal ligament space was narrower and the alveolar bone proper was sparser and less continuous in the hypofunction group than in the control group. Further, both the volume of the periodontal ligament and the volumetric ratio of the alveolar bone proper to the total tissue in the region of interest were significantly lower in the hypofunction group (p < 0.05). Conclusions Occlusal hypofunction induces atrophic changes in the periodontal ligament and alveolar bone proper of rat molars.

Hosomichi, Jun; Nakamura, Saeko; Ono, Takashi

2014-01-01

228

Distal movement of premolars to provide posterior abutments for missing molars.  

PubMed

In 24 patients with missing molar teeth in the upper and/or in the lower jaw, 32 premolars were distalized. The mean orthodontic distalizing distance was 9.4 mm (SD 2.6). After distalization all these teeth served as posterior abutments for fixed restorations. The investigation period ranged between 2.5 to 14.1 years, average 9.6 years (SD 3.2). The clinical examination criteria were sensitivity, mobility, probing depth, sulcus bleeding index; the radiologic criteria were root resorption (lateral and apical) marginal bone level and axial position. None of the 32 premolar abutments were lost during investigation period. All the teeth maintained their vitality. The measured probing depths and sulcus bleeding indices were low. Of the teeth tested 40.6% revealed localized lateral root resorption on the pressure side; the average postorthodontic depth of root resorption was 0.7 mm (SD 0.3), and the length 2.3 mm (SD 0.6). The follow-up examination revealed a partial repair of the lateral root lesions. The extent of apical root resorption amounted to 0.9 mm (SD 1.1). The marginal bone level showed a bone loss of 0.5 mm mesially and 0.2 mm distally. The findings confirm that the distalized premolar functioning as a posterior bridge abutment represents a prognostically favorable alternative to an implant. PMID:8638576

Diedrich, P R; Fuhrmann, R A; Wehrbein, H; Erpenstein, H

1996-04-01

229

Indirect pulp therapy in a symptomatic mature molar using calcium enriched mixture cement.  

PubMed

Dental pulp has the ability of repair/regeneration. Indirect pulp therapy (IPT) is recommended for pulp preservation in asymptomatic teeth with extremely deep caries as well as teeth with clinical symptoms of reversible pulpitis. In this case study, we performed IPT with calcium enriched mixture (CEM) cement on a symptomatic permanent molar. After clinical/radiographic examinations the tooth was diagnosed with irreversible pulpitis and associated apical periodontitis. IPT involved partial caries removal, the placement of CEM cement pulp cap and overlying adhesive permanent restoration. At the 1 week follow-up, patient's spontaneous symptoms had resolved. One-year follow-up demonstrated pulp vitality, clinical function, as well as the absence of pain/tenderness to percussion/palpation/cold sensitivity tests; periapical radiograph showed a healing periradicular lesion with newly formed bone, that is normal pulp with normal periodontium. These favorable results indicate that IPT/CEM may be a good treatment option in comparison to endodontic treatment in young patients. IPT of deep-caries lesion is an easier, more practical and valuable treatment plan than complete caries removal. PMID:23349584

Torabzadeh, Hassan; Asgary, Saeed

2013-01-01

230

Relationship between cusp size and occlusal wear pattern in Neanderthal and Homo sapiens first maxillary molars.  

PubMed

Tooth wear studies in mammals have highlighted the relationship between wear facets (attritional areas produced during occlusion by the contact between opposing teeth) and physical properties of the ingested food. However, little is known about the influence of tooth morphology on the formation of occlusal wear facets. We analyzed the occlusal wear patterns of first maxillary molars (M(1) s) in Neanderthals, early Homo sapiens, and contemporary modern humans. We applied a virtual method to analyze wear facets on the crown surface of three-dimensional digital models. Absolute and relative wear facet areas are compared with cusp area and cusp height. Although the development of wear facets partially follows the cusp pattern, the results obtained from the between-group comparisons do not reflect the cusp size differences characterizing these groups. In particular, the wear facets developed along the slopes of the most discriminate cusp between Neanderthals and Homo sapiens (hypocone) do not display any significant difference. Moreover, no correlations have been found between cusp size and wear facet areas (with the exception of the modern sample) and between cusp height and wear facet areas. Our results suggest that cusp size is only weakly related to the formation of the occlusal wear facets. Other factors, such as, diet, food processing, environmental abrasiveness, and nondietary habits are probably more important for the development and enlargement of wear facets, corroborating the hypotheses suggested from previous dental wear studies. PMID:21337711

Fiorenza, Luca; Benazzi, Stefano; Viola, Bence; Kullmer, Ottmar; Schrenk, Friedemann

2011-03-01

231

UPPER VS. LOWER MOLARS FOR CEMENTUM ANNULI AGE DETERMINATION OF DEER  

Microsoft Academic Search

Ages were determined for 23 black-tailed deer (Odocoileus hemionus columbianus) and 14 white-tailed deer (0. virginianus) by examination of cementum annuli of both upper and lower 1st molars. Although estimated ages were virtually the same for both upper and lower molars, the clarity of annuli was significantly greater in upper molars for both species. Abstract: Ages were determined for 23

DALE R. McCULLOUGH; PAUL BEIER

232

Automatic Molar Extraction from Dental Panoramic Radiographs for Forensic Personal Identification  

NASA Astrophysics Data System (ADS)

Measurement of an individual molar provides rich information for forensic personal identification. We propose a computer-based system for extracting an individual molar from dental panoramic radiographs. A molar is obtained by extracting the region-of-interest, separating the maxilla and mandible, and extracting the boundaries between teeth. The proposed system is almost fully automatic; all that the user has to do is clicking three points on the boundary between the maxilla and the mandible.

Samopa, Febriliyan; Asano, Akira; Taguchi, Akira

233

Human molars from later Pleistocene deposits of Witkrans Cave, Gaap Escarpment, Kalahari Margin  

Microsoft Academic Search

Human molars from travertine deposits of Witkrans Cave (Gaap Escarpment, northern Cape Province, South Africa) are described.\\u000a The Witkrans molars were discovered in direct association with later Pleistocene faunal remains and a sample of Middle Stone\\u000a Age artifacts (Peabody, 1954; Clark, 1971; Sampson, 1974; Klein, 1984; Volman, 1984). The morphology and dimensions of the\\u000a Witkrans molars resemble remains from other

Monte L. McCrossin

1992-01-01

234

World-volume action for fractional branes ? ? Work partially supported by the EC RTN programme HPRN-CT-2000-00131 in which G.S. is associated with Frascati-LNF  

Microsoft Academic Search

We study the world-volume action of fractional Dp-branes of type IIA string theory compactified on the orbifold T4\\/Z2. The geometric relation between these branes and wrapped branes is investigated using conformal techniques. In particular we examine in detail various scattering amplitudes and find that the leading low-energy interactions are consistent with the boundary action derived geometrically.

Paolo Merlatti; Gianluca Sabella

2001-01-01

235

Image analysis of the eruptive positions of third molars and adjacent second molars as indicators of age evaluation in Thai patients  

PubMed Central

Purpose This study was performed to determine the relationship between the stage of tooth eruption (both vertical and mesio-angular) and chronological age. Materials and Methods Indirect digital panoramic radiographs were used to measure the distances from the dentinoenamel junction (DEJ) of the second molars to the occlusal plane of the second molar teeth and of the adjacent third molars in 264 Thai males and 437 Thai females using ImageJ software. The ratio of those distances was calculated by patient age, and the correlation coefficient of the ratio of the third molar length to the second molar length was calculated. Results The correlation between the height of the vertically erupted upper third molar teeth and age was at the intermediate level. The age range of ?15 to <16 years was noted to be the range in which the correlation between the chronological age determined from the eruptional height and actual chronological age was statistically significant. The mean age of the female subjects, in which the position of the right upper third molar teeth was at or above the DEJ of the adjacent second molar but below one half of its coronal height was 19.9±2.6 years. That for the left side was 20.2±2.7 years. The mean ages of the male subjects were 20.1±3.3 years and 19.8±2.7 years for the right and left sides, respectively. Conclusion It might be possible to predict chronological age from the eruption height of the wisdom teeth. PMID:24380069

Pramojanee, Sakarat; Thaiupathump, Trasapong

2013-01-01

236

Partial Derivative Visualization Gallery  

NSDL National Science Digital Library

This resource is a small gallery of demos for illustrating partial derivatives geometrically. These animations can be used by instructors in a classroom setting or by students to aid in acquiring a visualization background for partial derivatives. Two file formats, gif and QuickTime files are used for the animations which can be downloaded.

Roberts, Lila F.; Hill, David R.

2004-11-11

237

Tubuloglomerular Feedback in Rats with Chronic Partial Bilateral Ureteral Obstruction  

Microsoft Academic Search

Rats with chronic partial unilateral ureteral obstruction (UUO) have a paradoxical resetting of the tubuloglomerular feedback (TGF) mechanism. During extracellular fluid volume expansion (VE) in control animals, a decrease in TGF sensitivity is normally noted. In rats with partial UUO, however, TGF sensitivity in the obstructed kidney was increased, associated with a relative reduction in single nephron glomerular filtration rate.

Peter Morsing; Arne Stenberg; Nils Wåhlin; A. Erik G. Persson

1995-01-01

238

Modified Distal Shoe Appliance for Premature Loss of Multiple Deciduous Molars: A Case Report  

PubMed Central

Preservation of the primary dentition until the normal time of exfoliation is one of the most important factor involved in preventive and interceptive dentistry. The premature loss of second primary molar before the eruption of permanent first molar can create a significant arch space/tooth size discrepancy. Distal shoe space maintainer is a valuable part of the Paediatric Dentist’s armamentarium in those cases where the second primary molar is prematurely lost and it helps to guide the first permanent molar into place. Conventional design poses various limitations in cases of premature loss of multiple deciduous molars. Thus, it is required to modify the conventional designs according to the needs of the patient. This case report describes an innovative modification of distal shoe appliance in cases of premature loss of multiple deciduous molars. In the present case, modification of distal shoe space maintainer was advocated because of inadequate abutments caused due to multiple loss of deciduous molars. Bilateral design of distal shoe was planned for unilateral loss of deciduous molars. PMID:25302284

K., Navin H.; Idris, Mohammed; Christopher, Pradeep; Rai, Niharika

2014-01-01

239

A new method to correct lingual rolling of lower molars (Amini twister).  

PubMed

In this report, we present an uncomplicated approach to overcome lingual rolling of mandibular molars during orthodontic treatment, by using rectangular NiTi arch wire in twist fashion through the molar tube. The sequential steps of the twist manoeuvre on a typodont and a case report are exhibited in this article. PMID:23729138

Amini, Fariborz; Poosti, Maryam

2013-01-01

240

High school students' ability to solve molarity problems and their analog counterparts  

Microsoft Academic Search

The study investigates the use of analog tasks for determining difficulties that high school chemistry students might encounter in solving molarity problems. Students (n = 619) from five schools completed three tests given throughout the school year. These were: an analog test, a molarity test, and a retention test. The analog task consisted of dissolving lemonade powder for solid sodium

Dorothy L. Gabel; K. V. Samuel

1986-01-01

241

Effect of submucosal and intramuscular dexamethasone on postoperative sequelae after third molar surgery: comparative study  

Microsoft Academic Search

We compared the effects of dexamethasone sodium phosphate given submucosally and intramuscularly on postoperative complications after removal of impacted lower third molars in a preliminary randomised prospective clinical trial. Thirty patients, each of whom required removal of a single impacted mandibular third molar under local anaesthesia, were randomly allocated to one of 3 groups of 10 each. The 2 experimental

Omer Waleed Majid; Waseem Khalid Mahmood

242

The influence of the group V/III molar precursor ratio on the structural properties  

E-print Network

, the precursors were temporally embedded in a nitrogen carrier gas stream, such that the total flow and pressureThe influence of the group V/III molar precursor ratio on the structural properties of InGaN layers, University of California, Irvine, CA 92697-2375, USA The influence of the group V/III molar precursor ratio

Dietz, Nikolaus

243

Modified distal shoe appliance for premature loss of multiple deciduous molars: a case report.  

PubMed

Preservation of the primary dentition until the normal time of exfoliation is one of the most important factor involved in preventive and interceptive dentistry. The premature loss of second primary molar before the eruption of permanent first molar can create a significant arch space/tooth size discrepancy. Distal shoe space maintainer is a valuable part of the Paediatric Dentist's armamentarium in those cases where the second primary molar is prematurely lost and it helps to guide the first permanent molar into place. Conventional design poses various limitations in cases of premature loss of multiple deciduous molars. Thus, it is required to modify the conventional designs according to the needs of the patient. This case report describes an innovative modification of distal shoe appliance in cases of premature loss of multiple deciduous molars. In the present case, modification of distal shoe space maintainer was advocated because of inadequate abutments caused due to multiple loss of deciduous molars. Bilateral design of distal shoe was planned for unilateral loss of deciduous molars. PMID:25302284

Bhat, Prasanna Kumar; K, Navin H; Idris, Mohammed; Christopher, Pradeep; Rai, Niharika

2014-08-01

244

Uniquely derived upper molar morphology of Eocene Amphipithecidae (Primates: Anthropoidea): homology and phylogeny.  

PubMed

The extinct Southeast Asian primate family Amphipithecidae is regularly cited in discussions of anthropoid origins, but its phylogenetic position remains controversial. In part, the lack of consensus regarding amphipithecid relationships can be attributed to uncertainty regarding the homology of upper molar structures in this group. Here, we describe a virtually pristine upper molar of Pondaungia cotteri from the late middle Eocene Pondaung Formation of Myanmar, which is the first example of a relatively unworn and well-preserved amphipithecid upper molar ever recovered. The distolingual upper molar cusp in this new specimen of Pondaungia appears to be a lingually displaced and enlarged metaconule, rather than a hypocone or pseudohypocone as previous workers have thought. Reassessment of the upper molar morphology of other amphipithecids and putative amphipithecids reveals a very similar pattern in Siamopithecus, Myanmarpithecus and Ganlea, all of which are interpreted as having upper molars showing many of the same derived features apparent in Pondaungia. In contrast, the upper molar morphology of Bugtipithecus diverges radically from that of undoubted amphipithecids, and the latter taxon is excluded from Amphipithecidae on this basis. Phylogenetic analyses of several character-taxon matrices culled from the recent literature and updated to reflect the new information on amphipithecid upper molar morphology yield similar results. Consensus tree topologies derived from these analyses support amphipithecid monophyly and stable relationships within Amphipithecidae. Amphipithecids appear to be stem members of the anthropoid clade. PMID:23823753

Coster, Pauline; Beard, K Christopher; Soe, Aung Naing; Sein, Chit; Chaimanee, Yaowalak; Lazzari, Vincent; Valentin, Xavier; Jaeger, Jean-Jacques

2013-08-01

245

Mole, Mole per Liter, and Molar: A Primer on SI and Related Units for Chemistry Students  

Microsoft Academic Search

This review provides historical background on the terms mole, mole per liter, and molar as it discusses their status with respect to the SI system of measurement. Currently the prevalent use of mole per liter and molar does not conform with the recommendations which apply to SI units in general. The article suggests an approach for dealing with this problem

George Gorin

2003-01-01

246

The Partial Derivative Machine  

NSDL National Science Digital Library

Research has shown that students struggle to understand the use of partial derivatives in thermodynamics. We have designed an apparatus, which we have called a Partial Derivative Machine, that serves as a mechanical analogue of a thermodynamic system. Using this device, students have a tangible way to wrestle with issues related to partial derivatives and thermodynamics, such as which variables are held fixed, how many variables are independent, and how energy can be added to a system. In this paper, we present a description of the apparatus, an introduction to the associated activities, and an overview of how this apparatus can be connected to thermodynamic systems.

Sherer, Grant; Kustusch, Mary B.; Manogue, Corinne A.; Roundy, David J.

2014-01-31

247

Volume crossover in deeply supercooled water adiabatically freezing under isobaric conditions  

NASA Astrophysics Data System (ADS)

The irreversible return of a supercooled liquid to stable thermodynamic equilibrium often begins as a fast process which adiabatically drives the system to solid-liquid coexistence. Only at a later stage will solidification proceed with the expected exchange of thermal energy with the external bath. In this paper we discuss some aspects of the adiabatic freezing of metastable water at constant pressure. In particular, we investigated the thermal behavior of the isobaric gap between the molar volume of supercooled water and that of the warmer ice-water mixture which eventually forms at equilibrium. The available experimental data at ambient pressure, extrapolated into the metastable region within the scheme provided by the reference IAPWS-95 formulation, show that water ordinarily expands upon (partially) freezing under isenthalpic conditions. However, the same scheme also suggests that, for increasing undercoolings, the volume gap is gradually reduced and eventually vanishes at a temperature close to the currently estimated homogeneous ice nucleation temperature. This behavior is contrasted with that of substances which do not display a volumetric anomaly. The effect of increasing pressures on the alleged volume crossover from an expanded to a contracted ice-water mixture is also discussed.

Aliotta, Francesco; Giaquinta, Paolo V.; Pochylski, Mikolaj; Ponterio, Rosina C.; Prestipino, Santi; Saija, Franz; Vasi, Cirino

2013-05-01

248

Management of unilaterally deep impacted first, second, and third mandibular molars.  

PubMed

Simultaneous impactions of first, second, and third permanent molars comprises a very rare clinical situation with diverse therapeutic approaches and is a difficult challenge for dentists. Early diagnosis and treatment of eruption disturbances contributes to optimal outcomes. This article reports the treatment of a teenager with severe impaction of right mandibular first, second, and third molars, which hinders the masticatory function and dental arch integrity. A decision-making process and a simple orthodontic technique are described. To shorten the treatment time and simplify the procedures, the impacted right mandibular third and second molars were orthodontically uprighted with an innovative tip-back cantilever. Subsequently, the deeply impacted right mandibular first molar was extracted with minimal obstacles. The combined surgical-orthodontic approach resolved a challenging clinical problem and eliminated the need for prosthetic or dental implant replacement of the impacted molars. Good occlusion, normal function, and a healthy periodontium of the patient were also achieved. PMID:21988519

Fu, Po-Sung; Wang, Jen-Chyan; Chen, Cheng-Hwei; Huang, Ta-Ko; Tseng, Chin-Huang; Hung, Chun-Cheng

2012-05-01

249

Management of an ectopically erupting permanent mandibular molar: a case report.  

PubMed

Ectopically erupting permanent first molars occur in approximately 3% to 4% of children, and presentation in the mandible is very rare. When the malocclusion warrants a nonextraction treatment plan in the mandible, early correction of an impacted ectopic molar with space regaining is appropriate. The purpose of this case report was to describe and document the correction of a severely impacted permanent mandibular left first molar in the early mixed dentition along with long-term results. A bilateral lingual arch was placed on the primary mandibular second molars with a Halterman-type extension in conjunction with a bonded button on the occlusal surface of the impacted permanent molar and chain elastic Early space regaining allowed future nonextraction treatment. PMID:18402102

Kennedy, David B

2008-01-01

250

Optimization of the mineral content in polymeric gels: The effect of calcium to phosphate molar ratio  

NASA Astrophysics Data System (ADS)

The influence of calcium to phosphate (Ca/P) molar ratio on the extent of mineralization in a model (poly)acrylamide gel was investigated under simulated physiological conditions. We hypothesized that the optimal growth of hydroxyapatite crystals will take place at the stoichiometric Ca/P molar ratio of 1.67. Phosphate ions were incorporated during the polymerization of the gel and mineralization was initiated by submersion of the gel in calcium acetate solution. Ca/P molar ratios were varied in the range of 0.5-5.0. The mineralized gel was characterized by Raman spectroscopy, scanning electron microscopy (SEM) and mineral weight fraction analysis via ashing. Raman spectra captured across the bulk of the gels indicated the presence of mineral at the core section. The phosphate symmetric stretching peak was observed in the range of 955-960 cm -1 which is characteristic of hydroxyapatite. SEM images showed that crystals formed at Ca/P=2.0 were denser and larger in size than at other molar ratios. In agreement with SEM images, the dry weight fraction of mineral reached the maximum at the molar ratio of 2.0 and the extent of mineralization rapidly declined as the molar ratio diverged from 2.0. Also, the crystallinity of the mineral was optimum at the molar ratio of 2.0. Thus it appears that for effective mineralization, the molar ratio of the two ions needs to be in excess of the stoichiometric requirement, suggesting that ions are expended in processes other than the formation and growth of hydroxyapatite crystals. Therefore, the optimal level of mineralization in biomimetic-based growth of calcium phosphate crystals in sol-gel environment requires consideration of a range of molar ratios as opposed to using the molar ratios corresponding to that of the crystal species intended to grow.

Das, Prasenjit; Akkus, Ozan; Azad, Abdul-Majeed

2005-07-01

251

Recurrent partial priapism.  

PubMed

Exploration of an unusual case of a painful, recurrent, perineal mass revealed partial priapism of the right corpora cavernosa. Etiology is speculative and no definitive therapy is offered. PMID:1274013

Gottesman, J E

1976-05-01

252

Partial Testing Design  

Cancer.gov

Statistical Software Partial Testing Design (Written by Stuart G. Baker) New Approach (with ROC curves): See Baker SG, Pinsky P. A proposed design and analysis for comparing digital and analog mammography: special ROC methods for cancer screening. JASA.

253

Partial Derivatives: Geometric Visualization  

NSDL National Science Digital Library

This write-pair-share activity presents Calculus III students with a worksheet containing several exercises that require them to find partial derivatives of functions of two variables. Afterwards, a series of Web-based animations are used to illustrate the surface of each function, the path of the indicated partial derivative for a specified value of the variable and the value of the derivative at each point along the path.

Rutledge, James

254

Molar absorptivities and reducing capacity of pyranoanthocyanins and other anthocyanins.  

PubMed

To improve accuracy in the determination of anthocyanin purity and succeeding antioxidant capacity, 1H and 13C nuclear magnetic resonance spectroscopy have been combined with high-performance liquid chromatography (HPLC) equipped with a diode array detector and UV-vis spectroscopy in the analysis of anthocyanidin 3-glycosides and 5-carboxypyranoanthocyanidin 3-glycosides. The molar absoptivity (epsilon) values were found to be relatively similar, in contrast to previously reported literature values, and the average epsilon values for both anthocyanidin 3-monoglycosides and 5-carboxypyranoanthocyanidin 3-glycosides were proposed to be 22,000 and 23,000 in acidified aqueous and methanolic solutions, respectively. To assess the influence of structure on the potential antioxidant capacity of anthocyanins, the 3-glucosides of pelargonidin (1), cyanidin (2), peonidin (3), delphinidin (4), petunidin (5), malvidin (6), 5-carboxypyranopelargonidin (8), 5-carboxypyranocyanidin (9), 5-carboxypyranodelphinidin (11), 5-carboxypyranopetunidin (12), and 5-carboxypyranomalvidin (13) and the 3-galactosides of cyanidin (7) and 5-carboxypyranocyanidin (14) were examined by a ferric ion reducing antioxidant power (FRAP) assay. The reducing capacities of the individual anthocyanins were in the range of 0.9-5.2 micromol of Trolox equivalents/micromol. The two 5-carboxypyranoanthocyanins 11 and 9 and the four common anthocyanins 2, 4, 7, and 14, all possessing pyrogallol or catechol type of B rings, showed the highest antioxidant capacity measured by FRAP. However, the inclusion of the 5-hydroxyl in the D ring and just one oxygen substituent on the B ring in 8 diminished the reducing capacity considerably. Correspondingly, electrochemical behavior of 5-carboxypyranoanthocyanidin 3-glucosides and anthocyanidin 3-glucosides was derived using HPLC coupled to a coulometric array detector set from 100 to 800 mV in increments of 100 mV. The relative order of the reducing capacity of the various 5-carboxypyranoanthocyanidin 3-glucosides and anthocyanidin 3-glucosides were nearly alike, whether determined by coulometric array detection or FRAP. PMID:18047275

Jordheim, Monica; Aaby, Kjersti; Fossen, Torgils; Skrede, Grete; Andersen, Øyvind M

2007-12-26

255

Radiographic evaluation of third molar genesis in Greek orthodontic patients  

PubMed Central

Objectives The study reported here investigated the first radiographic evidence of third molar (M3) formation, their incidence and distribution as well as their congenital absence on the right or the left side in either the maxilla or the mandible, in both male and female Greek orthodontic patients. Materials and methods A total of 618 panoramic radiographs were initially examined. After the application of inclusion/exclusion criteria, the group finally selected consisted of 428 patients (mean age 11.64 years, range 5–18): 179 males (mean age 11.73 ± 2.46) and 249 females (mean age 11.57 ± 2.45). The collected data were analyzed using SPSS software (IBM, Armonk, New York, NY, USA). The level of significance for all analyses was set to p = 0.05. The chi-square (?2) test was used to assess the relationships between variables. The Wilcoxon’s signed-rank test and the Mann-Whitney U test were also used for comparisons as well as the Spearman’s rho test for correlations. Results M3s were first detected in females at the age of 7 years whereas males followed one year later at the age of 8 years. A strong correlation between age and M3 development was revealed for both sexes (Spearman’s rho = 0.177, p = 0.05). Presence of all four M3s was the most common incidence (present in 70.8% of study subjects), followed by the agenesis of two (12.1%), agenesis of all four (8.4%), one (6.8%), and three (1.9%) M3s. Congenitally missing M3s in all subjects showed a significantly greater predilection for the maxilla over the mandible (19.6% and 15.5%, respectively) (Wilcoxon signed-rank test Z = ?2.404, p = 0.016). However, the distribution was found equal between the two sides of the jaws. The difference between the absent frequencies of M3s in the mandible and the maxilla was found statistically significant for the total sample (McNemar’s test, p < 0.001) and for males (p = 0.041) as well. Conclusion The study data may provide a reference for the M3 genesis in Greeks. PMID:24072974

Barka, Georgia; Marathiotis, Konstantinos; Protogerakis, Michael; Zafeiriadis, Andreas

2013-01-01

256

Two-Rooted Maxillary First Molars with Two Canals: A Case Series  

PubMed Central

Thorough understanding of the anatomic and internal morphology of a root canal system is absolutely essential for the success of endodontic treatment. Since permanent maxillary first molars have shown variation in internal anatomy, morphology, this tooth has been reviewed extensively. Presence of two canals in a two-rooted maxillary first molar has rarely been reported in studies describing tooth and root canal anatomies. In this report, three cases are presented, which involve the root canal treatment of maxillary first molars with fusion of the two buccal roots. PMID:23412400

Shakouie, Sahar; Mokhtari, Hadi; Ghasemi, Negin; Gholizadeh, Seddigheh

2013-01-01

257

Methanol partial oxidation reformer  

DOEpatents

A partial oxidation reformer is described comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell. 7 figs.

Ahmed, S.; Kumar, R.; Krumpelt, M.

1999-08-17

258

Oxygen partial pressure sensor  

DOEpatents

A method for detecting oxygen partial pressure and an oxygen partial pressure sensor are provided. The method for measuring oxygen partial pressure includes contacting oxygen to a solid oxide electrolyte and measuring the subsequent change in electrical conductivity of the solid oxide electrolyte. A solid oxide electrolyte is utilized that contacts both a porous electrode and a nonporous electrode. The electrical conductivity of the solid oxide electrolyte is affected when oxygen from an exhaust stream permeates through the porous electrode to establish an equilibrium of oxygen anions in the electrolyte, thereby displacing electrons throughout the electrolyte to form an electron gradient. By adapting the two electrodes to sense a voltage potential between them, the change in electrolyte conductivity due to oxygen presence can be measured. 1 fig.

Dees, D.W.

1994-09-06

259

Simplifying Chemical Reactor Design by using Molar Quantities Instead of Fractional Conversion.  

ERIC Educational Resources Information Center

Explains the advantages of using molar quantities in chemical reactor design. Advocates the use of differential versions of reactor mass balances rather than the integrated forms. Provides specific examples and cases to illustrate the principles. (ML)

Brown, Lee F.; Falconer, John L.

1987-01-01

260

How Many Digits Should We Use in Formula or Molar Mass Calculations?  

ERIC Educational Resources Information Center

The calculations of uncertainties in the formula or molar masses of compounds are streamlined. Three rules of increasing complexity are proposed, which overestimate the uncertainty so there is little if any risk that the true values are missed.

Svensson, Christer

2004-01-01

261

Accidental Displacement of Third Molar into the Sublingual Space: a Case Report  

PubMed Central

ABSTRACT Background Successful extraction of third molars depends on preoperative diagnosis and planning. Gold standard preoperative examinations are performed through computed tomography, decreasing risks and avoiding potential accidents. The present report highlights the value of preoperative examinations in face of accidentally displaced third molars. Methods An 18-years-old female patient underwent a third mandibular molar extraction with a general dentist. Accidentally, the mandibular left third molar was displaced into the sublingual space, making necessary a second surgical step. The surgery was interrupted and the patient was referred to an expert in maxillofacial surgery. Results After 21 days awaiting an asymptomatic health status, the second surgical step was successfully performed using multislice computed tomography as preoperative imaging guide. Conclusions The present case report highlights the clinical usefulness of imaging planning and informed consents in face of legal and ethic potential complaints. PMID:25386232

Garcia, Robson Rodrigues; Botelho, Tessa Lucena; Franco, Ademir; Silva, Rhonan Ferreira

2014-01-01

262

Laparoscopic retroperitoneal partial nephrectomy.  

PubMed

To our knowledge we report the initial case of laparoscopic partial nephrectomy performed completely via the retroperitoneal approach. The retroperitoneal space was developed by inflating a balloon. Renal parenchymal hemostasis was obtained by a newly designed double loop apparatus and the argon beam coagulator. Convalescence was rapid and no complications have been noted during a followup of 7 months. PMID:7933195

Gill, I S; Delworth, M G; Munch, L C

1994-11-01

263

Generalized Partial Directed Coherence  

Microsoft Academic Search

This paper re-examines the definition of partial directed coherence (PDC) which was recently introduced as a linear frequency-domain quantifier of the multivariate relationship between simultaneously observed time series for application in functional connectivity inference in neuroscience. The present reappraisal aims at improving PDC's performance under scenarios that involve severely unbalanced predictive modelling errors (innovations noise). The present modification turns out

L. A. Baccald; F. de Medicina

2007-01-01

264

Swallowed partial dentures  

PubMed Central

Swallowed or inhaled partial dentures can present a diagnostic challenge. Three new cases are described, one of them near-fatal because of vascular erosion and haemorrhage. The published work points to the importance of good design and proper maintenance. The key to early recognition is awareness of the hazard by denture-wearers, carers and clinicians. PMID:14749401

Hashmi, Syed; Walter, John; Smith, Wendy; Latis, Sergios

2004-01-01

265

Partial gravity habitat study  

NASA Technical Reports Server (NTRS)

The purpose of this study is to investigate comprehensive design requirements associated with designing habitats for humans in a partial gravity environment, then to apply them to a lunar base design. Other potential sites for application include planetary surfaces such as Mars, variable-gravity research facilities, and a rotating spacecraft. Design requirements for partial gravity environments include locomotion changes in less than normal earth gravity; facility design issues, such as interior configuration, module diameter, and geometry; and volumetric requirements based on the previous as well as psychological issues involved in prolonged isolation. For application to a lunar base, it is necessary to study the exterior architecture and configuration to insure optimum circulation patterns while providing dual egress; radiation protection issues are addressed to provide a safe and healthy environment for the crew; and finally, the overall site is studied to locate all associated facilities in context with the habitat. Mission planning is not the purpose of this study; therefore, a Lockheed scenario is used as an outline for the lunar base application, which is then modified to meet the project needs. The goal of this report is to formulate facts on human reactions to partial gravity environments, derive design requirements based on these facts, and apply the requirements to a partial gravity situation which, for this study, was a lunar base.

Capps, Stephen; Lorandos, Jason; Akhidime, Eval; Bunch, Michael; Lund, Denise; Moore, Nathan; Murakawa, Kiosuke

1989-01-01

266

Slip casting of partially stabilized zirconia  

SciTech Connect

The toughness of partially-stabilized zirconia has been studied for some time. The tetragonal phase in partially stabilized ZrO2 transforms to the monoclinic phase under the influence of stress. Partially-stabilized ZrO2 has enhanced tensile strength, good wear resistance and low friction coefficient, and has found industrial applications. This article describes the use of partially-stabilized zirconia in slip casting. Lab techniques of slip casting have been reported for nonplastic materials such as Al2O3, CaF2, CaO-stabilized ZrO2 and MgO. The article discusses the variation of slip density and firing temperature and also reports the preparation of specimens of CaOstabilized ZrO2 by slip casting from ethanol-based suspensions. The preparation of Y2O3-ZrO2 compositions by slip casting from aqueous suspension is also reported. A Y2O3 partially stabilized ZrO2 powder was used as a starting material. The densities of the cast specimens were measured from the volume and weight, and those of the sintered specimens were measured by a liquid displacement technique using distilled water. The concentation of the suspension strongly affects the relative density of the cast specimen and the firing shrinkage of the sintered specimen, while the relative density of the sintered specimen is independent of the concentration of the suspension.

Taguchi, H.; Miyamoto, H.; Takahashi, Y.

1985-02-01

267

Maxillary tuberosity fracture and subconjunctival hemorrhage following extraction of maxillary third molar  

PubMed Central

Extraction of teeth is the most common minor surgical procedure performed. Complication of extraction ranges from periodontal injury to fracture of jaw in the mandible and fracture of tuberosity and oroantral communication in the maxilla. Subconjunctival hemorrhage after extraction of maxillary molar is a very rare complication, and so far, only one case is reported in the literature. We report a case of subconjunctival hemorrhage with maxillary tuberosity fracture after maxillary third molar extraction. PMID:23633874

Thirumurugan, Kanagasabapathy; Munzanoor, Rathinam Ramesh Babu; Prasad, Gnanasekaran Arun; Sankar, Kannan

2013-01-01

268

Optimization of the mineral content in polymeric gels: The effect of calcium to phosphate molar ratio  

Microsoft Academic Search

The influence of calcium to phosphate (Ca\\/P) molar ratio on the extent of mineralization in a model (poly)acrylamide gel was investigated under simulated physiological conditions. We hypothesized that the optimal growth of hydroxyapatite crystals will take place at the stoichiometric Ca\\/P molar ratio of 1.67. Phosphate ions were incorporated during the polymerization of the gel and mineralization was initiated by

Prasenjit Das; Ozan Akkus; Abdul-Majeed Azad

2005-01-01

269

Alternative approach to management of early loss of second primary molar: a clinical case report.  

PubMed

Preservation of space after premature loss of the second primary molar is essential to prevent mesial drifting of the permanent first molar. Various modifications of distal shoe space maintainers, which have been documented, are all nonfunctional in nature. This paper describes an innovative design of a functional distal shoe space maintainer that is intended to overcome the disadvantages of conventional non-functional space maintainers and that does not hamper the periodontal status of the abutment tooth. PMID:25087351

Agarwal, Ravi; Chaudhry, Kalpna; Yeluri, Ramakrishna; Singh, Chanchal; Munshi, Autar K

2014-05-01

270

Investigation on the utility of permanent maxillary molar cusp areas for sex estimation  

Microsoft Academic Search

Digital photogrammetric methods were employed to assess the level of sexual dimorphism present in permanent maxillary molar\\u000a cusp areas of black South Africans (130 males, 105 females). Odontometric standards were then developed for diagnosing sex,\\u000a based on the cusp area data derived for these teeth. Results demonstrated that all cusp area measurements of both the first\\u000a and second maxillary molars

P. James Macaluso Jr

2011-01-01

271

Thermochemical studies for determination of the molar enthalpy of formation of aniline derivatives  

Microsoft Academic Search

The standard (po=0.1 MPa) molar enthalpies of combustion atT=298.15 K were measured by static bomb combustion calorimetry for liquidN,N-diethylaniline,N,N-dimethyl-m-toluidine,N,N-dimethyl-p-toluidine, andN-ethyl-m-toluidine. Vaporization enthalpies forN,N-dimethyl-m-toluidine andN-ethyl-m-toluidine were determined by correlation gas chromatography. Derived standard molar values of ?fH

Manuel A. V. Ribeiro da Silva; Maria Dores M. C. Ribeiro da Silva; Maria Fatima B. M. Monteiro; Maria Luísa A. C. N. Gomes; James S. Chickos; Anjanette P. Smith; Joel F. Liebman

1996-01-01

272

The addition of hydrogen bromide to propyne in equal molar quantities  

E-print Network

CONSTANTS, EXPERIMENTAL RESULTS. DISCUSSION, CONCLUSION. APPENDIX, REFERENCES. Page 10 16 17 22 2B 34 TABLE OF FIGURES Figure Apparatus Diagram. Infrared Spectra of Fraction Distilling Between 56 and 59 Degrees Centigrade (Reaction 58...). Page 12 Infrared Spectra (Reaction 58). Infrared Spectra (Reaction 54), of l-Bromopropene of 2-Bromopropene THE ADDITION OF HYDROGEN BROMIDE TO PROPYNE IN EQUAL MOLAR QUANTITIES INTRODUCTION In a reaction involving equal molar quantities...

Mejia, Joe Marcus

2012-06-07

273

Student (Mis)application of Partial Differentiation to Material Properties  

NSDL National Science Digital Library

Students in upper-level undergraduate thermodynamics courses were asked about the relationship between the complementary partial derivatives of the isothermal compressibility and the thermal expansivity of a substance. Both these material properties can be expressed with first partial derivatives of the system volume. Several of the responses implied difficulty with the notion of variables held fixed in a partial derivative. Specifically, when asked to find the partial derivative of one of these quantities with respect to a variable that was initially held fixed, a common response was that this (mixed second) partial derivative must be zero. We have previously reported other related difficulties in the context of the Maxwell relations, indicating persistent confusion applying partial differentiation to state functions. We present results from student homework and examination questions and briefly discuss an instructional strategy to address these issues.

Bucy, Brandon; Thompson, John R.; Mountcastle, Donald B.

2007-11-25

274

Combined Reforming and Partial Oxidation of CO 2 -Containing Natural Gas Using an AC Multistage Gliding Arc Discharge System: Effect of Stage Number of Plasma Reactors  

Microsoft Academic Search

The effect of stage number of multistage AC gliding arc discharge reactors on the process performance of the combined reforming\\u000a and partial oxidation of simulated CO2-containing natural gas having a CH4:C2H6:C3H8:CO2 molar ratio of 70:5:5:20 was investigated. For the experiments with partial oxidation, either pure oxygen or air was used\\u000a as the oxygen source with a fixed hydrocarbon-to-oxygen molar ratio

Nongnuch Rueangjitt; Wariya Jittiang; Krittiya Pornmai; Jintana Chamnanmanoontham; Thammanoon Sreethawong; Sumaeth Chavadej

2009-01-01

275

Partial and Total Differentiation  

Microsoft Academic Search

\\u000a The notion of derivative of a function of one-variable does not really have a solitary analogue for functions of several variables.\\u000a Indeed, for a function of two (or more) variables, there is a plethora of derivatives depending on whether we choose to become\\u000a partial to one of the variables, or opt to move about in a specific direction, or prefer

Sudhir R. Ghorpade; Balmohan V. Limaye

276

Partially Reflected Diffusion  

E-print Network

The radiation (reaction, Robin) boundary condition for the continuum diffusion equation is widely used in chemical and biological applications to express reactive boundaries. The underlying trajectories of the diffusing particles are believed to be partially absorbed and partially reflected at the reactive boundary, however, the relation between the reaction (radiation) constant in the Robin boundary condition and the reflection probability is still unclear. In this paper we clarify the issue by finding the relation between the reaction (radiation) constant and the absorption probability of the diffusing trajectories at the boundary. We analyze the Euler scheme for the underlying It\\^o dynamics, which is assumed to have variable drift and diffusion tensor, with partial reflection at the boundary. Trajectories that cross the boundary are terminated with a given probability and otherwise are reflected in a normal or oblique direction. We use boundary layer analysis of the corresponding Wiener path integral to resolve the non-uniform convergence of the probability density function of the numerical scheme to the solution of the Fokker-Planck equation with the Robin boundary condition, as the time step is decreased. We show that the Robin boundary condition is recovered in the limit iff trajectories are reflected in the co-normal direction. We find the relation of the reactive constant to the termination probability. We show the effect of using the new relation in numerical simulations.

A. Singer; Z. Schuss; D. Holcman

2006-06-19

277

Influence of gel aging and Na 2SiO 3\\/H 2O molar ratio on monolithicity and physical properties of water–glass-based aerogels dried at atmospheric pressure  

Microsoft Academic Search

The experimental results on the effects of gel aging and molar ratio of Na2SiO3\\/H2O on monolithicity and physical properties of water–glass-based silica aerogels are presented. The aerogels were prepared by atmospheric pressure drying using a silylation process. The gel-aging period was varied from 1 to 96h. The percentage of volume shrinkage and hence the density and optical transmission of the

A. Venkateswara Rao; A. Parvathy Rao; M. M. Kulkarni

2004-01-01

278

Caries management strategies for primary molars: 1-yr randomized control trial results.  

PubMed

Minimal invasive approaches to managing caries, such as partial caries removal techniques, are showing increasing evidence of improved outcomes over the conventional complete caries removal. There is also increasing interest in techniques where no caries is removed. We present the 1-yr results of clinical efficacy for 3 caries management options for occlusoproximal cavitated lesions in primary molars: conventional restorations (CR; complete caries removal and compomer restoration), Hall technique (HT; no caries removal, sealing in with stainless steel crowns), and nonrestorative caries treatment (NRCT; no caries removal, opening up the cavity, teaching brushing and fluoride application). In sum, 169 children (3-8 yr old; mean, 5.56 ± 1.45 yr) were enrolled in this secondary care-based, 3-arm, parallel-group, randomized clinical trial. Treatments were carried out by specialist pediatric dentists or postgraduate trainees. One lesion per child received CR, HT, or NRCT. Outcome measures were clinical failure rates, grouped as minor failure (restoration loss/need for replacement, reversible pulpitis, caries progression, etc.) and major failure (irreversible pulpitis, abscess, etc.). There were 148 children (87.6%) with a minimum follow-up of 11 mo (mean, 12.23 ± 0.98 mo). Twenty teeth were recorded as having at least 1 minor failure: NRCT, n = 8 (5%); CR, n = 11 (7%); HT, n = 1 (1%) (p = .002, 95% CI = 0.001 to 0.003). Only the comparison between NRCT and CR showed no significant difference (p = .79, 95% CI = 0.78 to 0.80). Nine (6%) experienced at least 1 major failure: NRCT, n = 4 (2%); CR, n = 5 (3%); HT, n = 0 (0%) (p = .002, 95% CI = 0.001 to 0.003). Individual comparison of NRCT and CR showed no statistically significant difference in major failures (p = .75, 95% CI = 0.73 to 0.76). Success and failure rates were not significantly affected by pediatric dentists' level of experience (p = .13, 95% CI = 0.12 to 0.14). The HT was significantly more successful clinically than NRCT and CR after 1 yr, while pairwise analyses showed comparable results for treatment success between NRCT and CR (ClinicalTrials.gov NCT01797458). PMID:25216660

Santamaria, R M; Innes, N P T; Machiulskiene, V; Evans, D J P; Splieth, C H

2014-11-01

279

Partial solvability from Duality Transformations  

E-print Network

When weak and strong coupling expansions describe different phases, their radii of convergence correspond to the extent of these phases. We study finite size systems for which both series expansions are analytic and must therefore converge to the very same function. Equating these expansions leads to severe constraints which "partially solve" various systems. We examine as concrete test cases (both ferromagnetic and spin-glass) Ising models and gauge type theories on finite periodic hypercubic lattices in 1hardness of general D>2 Ising theories is "localized" to this fraction. When the self-duality of the D=2 Ising model is invoked, the number of requisite coefficients is further halved; all remaining coefficients are determined by linear combinations of this subset. The obtained linear equations imply an extensive set of geometrical relations between the numbers of closed loops/surfaces, etc., of fixed size in general dimensions and relate derived coefficients to polytope volumes. Our analysis sheds light on a connection between solvability and dualities by exhausting all of the relations that dualities imply on series expansion. General self-dualities (for both finite and infinite size systems) solve the "Babbage equation" F(F(z)) = z with F a map relating weak to strong couplings.

Zohar Nussinov; Gerardo Ortiz; Mohammad-Sadegh Vaezi

2013-11-26

280

Kinetic studies of the partial oxidation of isooctane for hydrogen production over a nickel–alumina catalyst  

Microsoft Academic Search

The kinetics of the catalytic partial oxidation of isooctane for hydrogen (H2) production over a stable Ni\\/?-Al2O3 catalyst was investigated at atmospheric pressure in the temperature range of 863–913K, ratio of weight of catalyst to the molar feed rate of isooctane (W\\/FiC8o) in the range of 7.09–30.89kgmol-1, and molar feed ratio O2\\/i-C8H18 of 4.0 in a 12.7mm diameter Inconel micro-reactor

Hussam H. Ibrahim; Raphael O. Idem

2006-01-01

281

Degeneration of fungiform and circumvallate papillae following molar extraction in rats.  

PubMed

Abstract Objective. Proper occlusion facilitates food intake and gustatory function is indispensable for the enjoyment of food. Although an interaction between dentoalveolar and gustatory afferent neurons has been suggested by previous studies, the relationship between occlusion and gustation remains unclear. This study investigated the effect of upper molar extraction which diminished occlusal support on peripheral gustatory receptors in rats. Materials and methods. Thirty-six 7-week-old male Wistar rats were randomly assigned to either the experimental or the control group. All maxillary molars were extracted from rats in the experimental group under anesthesia, while a sham operation was conducted in the control group. The rats were euthanized 7, 14 or 28 days after the procedure. The morphology of the circumvallate papillae and taste buds using immunohistochemical methods and the fungiform papillae were visualized with 1% methylene blue. Results. Defects in the gustatory epithelium were observed after maxillary molar extraction. Rats in the experimental group had significantly fewer fungiform papillae, narrower circumvallate papillae, shallower trench depth, smaller trench area, smaller taste bud area, lower ratios of taste bud area to trench area and fewer taste buds than those in the control group. Conclusions. The findings indicate that molar extraction would affect peripheral gustatory receptors. This is the first study to characterize changes in rat fungiform and circumvallate papillae after maxillary molar extraction. This study suggests a possible synergic relationship between dentoalveolar perception and gustatory function, which has clinical implications that occlusion is closely correlated with gustatory perception. PMID:24866919

Hsu, Jui-Chin; Watari, Ippei; Ono, Rieko; Privatananupunt, Jutiporn; Mizumachi-Kubono, Mariko; Honda, Koji; Ishida, Yuji; Ono, Takashi

2014-11-01

282

In vitro evaluation of an alternative method to bond molar tubes  

PubMed Central

Despite the advances in bonding materials, many clinicians today still prefer to place bands on molar teeth. Molar bonding procedures need improvement to be widely accepted clinically. Objective The purpose of this study was to evaluate the shear bond strength when an additional adhesive layer was applied on the occlusal tooth/tube interface to provide reinforcement to molar tubes. Material and methods Sixty third molars were selected and allocated to the 3 groups: group 1 received a conventional direct bond followed by the application of an additional layer of adhesive on the occlusal tooth/tube interface, group 2 received a conventional direct bond, and group 3 received a conventional direct bond and an additional cure time of 10 s. The specimens were debonded in a universal testing machine. The results were analyzed statistically by ANOVA and Tukey’s test (?=0.05). Results Group 1 had a significantly higher (p<0.05) shear bond strength compared to groups 2 and 3. No difference was detected between groups 2 and 3 (p>0.05). Conclusions The present in vitro findings indicate that the application of an additional layer of adhesive on the tooth/tube interface increased the shear bond strength of the bonded molar tubes. PMID:21437468

PINZAN-VERCELINO, Célia Regina Maio; PINZAN, Arnaldo; GURGEL, Júlio de Araújo; BRAMANTE, Fausto Silva; PINZAN, Luciana Maio

2011-01-01

283

Mineralization of mandibular third molars can estimate chronological age--Brazilian indices.  

PubMed

Forensic age estimation is an important element of anthropological research, as it produces one of the primary sources of data that researchers use to establish the identity of a person living or the identity of unknown bodily remains. The aim of this study was to determine if the chronology of third molar mineralization could be an accurate indicator of estimated age in a sample Brazilian population. If so, mineralization could determine the probability of an individual being 18 years or older. The study evaluated 407 panoramic radiographs of males and females from the past 5 years in order to assess the mineralization status of the mandibular third molars. The evaluation was carried out using an adaptation of Demirjian's system. The results indicated a strong correlation between chronological age and the mineralization of the mandibular third molars. The results indicated that modern Brazilian generation tends to demonstrate an earlier mandibular third molar mineralization than older Brazilian generation and people of other nationalities. Males reached developmental stages slightly earlier than females, but statistically significant differences between the sex were not found. The probability that an individual with third molar mineralization stage H had reached an age of 18 years or older was 96.8-98.6% for males and females, respectively. PMID:22257966

de Oliveira, Fernando Toledo; Capelozza, Ana Lúcia Álvares; Lauris, José Roberto Pereira; de Bullen, Izabel Regina Fischer Rubira

2012-06-10

284

Evc regulates a symmetrical response to Shh signaling in molar development.  

PubMed

Tooth morphogenesis involves patterning through the activity of epithelial signaling centers that, among other molecules, secrete Sonic hedgehog (Shh). While it is known that Shh responding cells need intact primary cilia for signal transduction, the roles of individual cilia components for tooth morphogenesis are poorly understood. The clinical features of individuals with Ellis-van Creveld syndrome include various dental anomalies, and we show here that absence of the cilial protein Evc in mice causes various hypo- and hyperplasia defects during molar development. During first molar development, the response to Shh signaling is progressively lost in Evc-deficient embryos and, unexpectedly, the response consistently disappears in a buccal to lingual direction. The important role of Evc for establishing the buccal-lingual axis of the developing first molar is also supported by a displaced activity of the Wnt pathway in Evc mutants. The observed growth abnormalities eventually manifest in first molar microdontia, disruption of molar segmentation and symmetry, root fusions, and delayed differentiation. Analysis of our data indicates that both spatially and temporally disrupted activities of the Shh pathway are the primary cause for the variable dental anomalies seen in patients with Ellis-van Creveld syndrome or Weyers acrodental dysostosis. PMID:23315474

Nakatomi, M; Hovorakova, M; Gritli-Linde, A; Blair, H J; MacArthur, K; Peterka, M; Lesot, H; Peterkova, R; Ruiz-Perez, V L; Goodship, J A; Peters, H

2013-03-01

285

Comparison of dental measurement systems for taxonomic assignment of Neanderthal and modern human lower second deciduous molars.  

PubMed

Traditional morphometric approaches for taxonomic assignment of Neanderthal and modern human dental remains are mainly characterized by caliper measurements of tooth crowns. Several studies have recently described differences in dental tissue proportions and enamel thickness between Neanderthal and modern human teeth. At least for the lower second deciduous molar (dm(2)), a three-dimensional lateral relative enamel thickness index has been proposed for separating the two taxa. This index has the advantage over other measurements of being applicable to worn teeth because it ignores the occlusal aspect of the crown. Nevertheless, a comparative evaluation of traditional crown dimensions and lateral dental tissue proportion measurements for taxonomic assignment of Neanderthal and modern human dm(2)s has not yet been performed. In this study, we compare various parameters gathered from the lateral aspects of the crown. These parameters include crown diameters, height of the lateral wall of the crown (lateral crown height = LCH), lateral enamel thickness, and dentine volume of the lateral wall, including the volume of the coronal pulp chamber (lateral dentine plus pulp volume = LDPV), in a 3D digital sample of Neanderthal and modern human dm(2)s to evaluate their utility in separating the two taxa. The LDPV and the LCH allow us to discriminate between Neanderthals and modern humans with 88.5% and 92.3% accuracy, respectively. Though our results confirm that Neanderthal dm(2)s have lower relative enamel thickness (RET) index compared with modern humans (p = 0.005), only 70% of the specimens were correctly classified on the basis of the RET index. We also emphasize that results of the lateral enamel thickness method depend on the magnitude of the interproximal wear. Accordingly, we suggest using the LCH or the LDPV to discriminate between Neanderthal and modern human dm(2)s. These parameters are more independent of interproximal wear and loss of lateral enamel. PMID:21624638

Benazzi, Stefano; Fornai, Cinzia; Bayle, Priscilla; Coquerelle, Michael; Kullmer, Ottmar; Mallegni, Francesco; Weber, Gerhard W

2011-09-01

286

A Prescription for Partial Synchrony  

E-print Network

Algorithms in message-passing distributed systems often require partial synchrony to tolerate crash failures. Informally, partial synchrony refers to systems where timing bounds on communication and computation may exist, but the knowledge...

Sastry, Srikanth

2012-07-16

287

Formation of polyelectrolyte complexes with diethylaminoethyl dextran: Charge ratio and molar mass effect.  

PubMed

The formation of polyelectrolyte complexes (PECs) between carboxymethyl pullulan and DEAE Dextran, was investigated, in dilute solution, with emphasis on the effect of charge density (molar ratio or pH) and molar masses. Electrophoretic mobility measurements have evidenced that insoluble PECs (neutral electrophoretic mobility) occurs for charge ratio between 0.6 (excess of polycation) and 1 (stoichiometry usual value) according to the pH. This atypical result is explained by the inaccessibility of some permanent cationic charge when screened by pH dependant cationic ones (due to the Hoffman alkylation). Isothermal titration calorimetry (ITC) indicates an endothermic formation of PEC with a binding constant around 10(5)Lmol(-1). Finally asymmetrical flow field flow fractionation coupled on line with static multi angle light scattering (AF4/MALS) evidences soluble PECs with very large average molar masses and size around 100nm, in agreement with scrambled eggs multi-association between various polyelectrolyte chains. PMID:25256478

Le Cerf, Didier; Pepin, Anne Sophie; Niang, Pape Momar; Cristea, Mariana; Karakasyan-Dia, Carole; Picton, Luc

2014-11-26

288

Routine antibiotic prophylaxis is not necessary during operations to remove third molars.  

PubMed

The purpose of this study was to evaluate the efficacy of antibiotic prophylaxis during removal of impacted third molars. We studied 150 patients with impacted mandibular or maxillary third molars who were divided randomly into three groups. The first was given amoxicillin 2g combined with clavulanic acid, orally daily for 5 days postoperatively; starting at the end of the operation. The second group was given the same drugs but the regimen started 5 days before the operation. The third was given no antibiotics. Pain, infection, swelling, alveolar osteitis, and interincisal mouth opening (mm) were evaluated. There were no significant differences among the groups in the incidence of these complications. We cannot recommend routine oral antibiotic prophylaxis in third molar surgery. PMID:17188409

Atao?lu, Hanife; Oz, Gülsün Yildirim; Candirli, Celal; Kizilo?lu, Dilek

2008-03-01

289

Asymmetry in mesial root number and morphology in mandibular second molars: a case report.  

PubMed

Ambiguity in the root morphology of the mandibular second molars is quite common. The most common root canal configuration is 2 roots and 3 canals, nonetheless other possibilities may still exist. The presence of accessory roots is an interesting example of anatomic root variation. While the presence of radix entomolaris or radix paramolaris is regarded as a typical clinical finding of a three-rooted mandibular second permanent molar, the occurrence of an additional mesial root is rather uncommon and represents a possibility of deviation from the regular norms. This case report describes successful endodontic management of a three-rooted mandibular second molar presenting with an unusual accessory mesial root, which was identified with the aid of multiangled radiographs and cone-beam computed tomography imaging. This article also discusses the prevalence, etiology, morphological variations, clinical approach to diagnosis, and significance of supernumerary roots in contemporary clinical dentistry. PMID:24516829

Nayak, Gurudutt; Shetty, Shashit; Shekhar, Rhitu

2014-02-01

290

In-depth morphological study of mesiobuccal root canal systems in maxillary first molars: review  

PubMed Central

A common failure in endodontic treatment of the permanent maxillary first molars is likely to be caused by an inability to locate, clean, and obturate the second mesiobuccal (MB) canals. Because of the importance of knowledge on these additional canals, there have been numerous studies which investigated the maxillary first molar MB root canal morphology using in vivo and laboratory methods. In this article, the protocols, advantages and disadvantages of various methodologies for in-depth study of maxillary first molar MB root canal morphology were discussed. Furthermore, newly identified configuration types for the establishment of new classification system were suggested based on two image reformatting techniques of micro-computed tomography, which can be useful as a further 'Gold Standard' method for in-depth morphological study of complex root canal systems. PMID:23493453

Chang, Seok-Woo; Lee, Jong-Ki; Lee, Yoon

2013-01-01

291

Partially filled electrodes for digital microfluidic devices  

NASA Astrophysics Data System (ADS)

As digital microfluidics technology evolves, the need for integrating additional elements (e.g., sensing/detection and heating elements) on the electrode increases. Consequently, electrode area for droplet actuation is reduced to create space for accommodating these additional elements, which undesirably affects force generation. Electrodes cannot simply be scaled larger to compensate for this loss of force, as this would also increase droplet volume and thereby compromise the advantages thought in miniaturization. Here, we present a study evaluating, numerically with preliminary experimental verification, different partially filled electrode designs and suggesting designs that combine high actuation forces with a large reduction in electrode area.

Pyne, D. G.; Salman, W. M.; Abdelgawad, M.; Sun, Y.

2013-07-01

292

Partial Evaluation Using Dependence Graphs  

Microsoft Academic Search

This thesis describes the use of program dependence graphs, as opposed to control flow graphs, as the basis for the partial evaluation of imperative programs. Partial evaluation is a program specialization operation in which programs with multiple inputs are specialized to take into account known values for some of their inputs. Thus, the result of partially evaluating a program given

Manuvir Das

1998-01-01

293

Free alg's via partial alg's  

E-print Network

Free alg's via functor on partial alg's Dion Coumans and Sam van Gool Free algebra step-by-step Free image-total functor Application to KB Free algebras via a functor on partial algebras Dion Coumans / 16 #12;Free alg's via functor on partial alg's Dion Coumans and Sam van Gool Free algebra step

van Suijlekom, Walter

294

Prevention of localized osteitis in mandibular third-molar sites using platelet-rich fibrin.  

PubMed

Purpose. To review our experience utilizing platelet rich fibrin (PRF), which is reported to aid in wound healing of extraction sites, for the prevention of localized osteitis following lower third-molar removal. Materials and Methods. PRF was placed in the mandibular third-molar extraction sites, 200 sites total, on 100 consecutive patients treated in our practice, by the authors. The patients were managed with standard surgical techniques, intraoperative IV antibiotic/steroid coverage, and routine postoperative narcotic analgesics/short-term steroid coverage. All patients were reevaluated for localized osteitis within 7-10 days of the surgery. A comparison group consisted of 100 consecutive patients who underwent bilateral removal of indicated mandibular wisdom teeth and did not receive PRF placement within the lower third molar surgical sites. Results. The incidence of localized osteitis (LO) following removal of 200 lower third molars with simultaneous PRF placement within the extraction site was 1% (2 sites out of 200). The group of patients whose mandibular 3rd molar sockets were not treated with PRF demonstrated a 9.5% (19 sites out of 200) incidence of localized osteitis. The latter group also required 6.5 hours of additional clinical time to manage LO than the study group who received PRF. Conclusions. This retrospective review demonstrated that preventative treatment of localized osteitis can be accomplished using a low cost, autogenous, soluble, biologic material, PRF, that PRF enhanced third-molar socket healing/clot retention and greatly decreased the clinical time required for postoperative management of LO. PMID:23653648

Hoaglin, Donald R; Lines, Gary K

2013-01-01

295

Long-Term Clinical Performance of Aesthetic Restorations in Primary Molars: A Case Report  

PubMed Central

There is a great diversity of restorative materials and techniques for deciduous molars with significant coronal destruction, including resin composite restorations and biologic restorations (portions of natural teeth). By using 4 evaluation methods, this study aimed at longitudinally evaluating the effectiveness of restorations in the deciduous molars of a patient having high caries activity, using adhesive techniques. The evaluation methods consisted of the fibre-optic transillumination method, clinical evaluation based on the United States Public Health Service criteria, radiographs, and an indirect method, scanning electron microscopy. Despite the patient's poor biofilm control, the restorative techniques were shown to be efficacious, particularly the biologic restorative technique. PMID:22567439

Pomarico, Luciana; Neves, Beatriz Goncalves; Maia, Lucianne Cople; Primo, Laura Guimaraes

2011-01-01

296

Upper molar distalization on palatal miniscrews: an easy to manage palatal appliance.  

PubMed

Upper molar distalization supported by miniscrews has become increasingly popular in the last years. A detailed clinical and lab procedure for the realization of a distalization appliance (fast back or distal jet) connected to miniscrews inserted in the anterior region of the palate is presented. A case report illustrates the use of a fast back appliance supported by miniscrews to correct the mesial shift of the molars and of the premolars as a consequence of an early loss of the maxillary deciduous canines. PMID:22583590

Huanca Ghislanzoni, Luis Tomas; Piepoli, Claudio

2012-05-01

297

The molar enthalpies of solution and vapour pressures of saturated aqueous solutions of some ammonium salts  

Microsoft Academic Search

Vapour pressures of water over saturated solutions of ammonium bromide, ammonium dihydrogen phosphate, ammonium thiosulfate, ammonium persulfate, ammonium acetate, ammonium oxalate and ammonium tartrate were determined as a function of temperature. These vapour pressures were used to evaluate the water activities, osmotic coefficients and molar enthalpies of vaporization. Molar enthalpies of solution of ammonium bromide ?solHm(NH4Br, T=293.97K, m=0.1030mol·kg?1)=(17.4±0.5)kJ·mol?1; ammonium hydrogen

Alexander Apelblat; Eli Korin

2003-01-01

298

Nonsurgical Endodontic Retreatment of Maxillary Second Molar with Two Palatal Root Canals: A Case Report  

PubMed Central

Successful endodontic treatment requires thorough knowledge regarding each root canal system of any tooth and probability of extra canals should be considered. Second maxillary molar with two palatal root canals is not frequent and its incidence reported in literatures is about 0.4–2%. The present case report describes non-surgical retreatment of maxillary second mo-lar with two palatal root canals. Radiographic interpretation is difficult in this region; so, very careful examination of pulpal space and using supportive devices such as loupe and operating microscope is recommended to discover any unusual anat-omic features like extra canals. PMID:22991641

Eskandarinezhad, Mahsa; Ghasemi, Negin

2012-01-01

299

A Comparative Evaluation of Hydroxyapatite Crystals and Glutaraldehyde as Agents for Pulpotomy in Deciduous Molars  

PubMed Central

Purpose: To evaluate and compare clinically and radiographically use of hydroxyapatite crystals and 2% glutaraldehyde as a pulpotomy agent. Method: Thirty deciduous molars were treated with pulpotomy using hydroxyapatite crystals and 2% glutaraldehyde. Results: Clinical and radiographic findings were observed at three months and six months. The success rate was found to be 100% clinically and 80.33% radiographically in the hydroxyapatite crystals group and 100% clinically and radiographically in the glutaraldehyde group. Clinical significance: The results of this study revealed that hydroxyapatite crystals is a potential pulpotomy agent for deciduous molars.

Adlakha, Vivek Kumar; Chandna, Preetika; Joshi, JL; Thomas, AM; Singh, Namita

2009-01-01

300

Negative urine pregnancy test in a molar pregnancy: is it possible?  

PubMed

A urine pregnancy test is commonly used to detect pregnancy and is based on finding intact ?-human chorionic gonadotrophin (hCG) molecules in the urine by an immunoassay system. However, the significantly large amount of ?-hCG in molar pregnancy may paradoxically lead to a false-negative result due to a phenomenon known as the 'high dose hook effect'. A case of molar pregnancy with negative urine pregnancy test but very high serum ?-hCG is reported. Every obstetrician should be aware of this limitation in the presence of a high index of suspicion of gestational trophoblastic disease but negative urine pregnancy test. PMID:25378114

Nigam, Aruna; Kumari, Archana; Gupta, Nidhi

2014-01-01

301

Partial LLL Reduction  

E-print Network

The Lenstra-Lenstra-Lovasz (LLL) reduction has wide applications in digital communications. It can greatly improve the speed of the sphere decoding (SD) algorithms for solving an integer least squares (ILS) problem and the performance of the Babai integer point, a suboptimal solution to the ILS problem. Recently Ling and Howgrave-Graham proposed the so-called effective LLL (ELLL) reduction. It has less computational complexity than LLL, while it has the same effect on the performance of the Babai integer point as LLL. In this paper we propose a partial LLL (PLLL) reduction. PLLL avoids the numerical stability problem with ELLL, which may result in very poor performance of the Babai integer point. Furthermore, numerical simulations indicated that it is faster than ELLL. We also show that in theory PLLL and ELLL have the same effect on the search speed of a typical SD algorithm as LLL.

Xie, Xiaohu; Borno, Mazen Al

2012-01-01

302

Computation of Partially Inflated Shapes of Stratospheric Balloon Structures  

E-print Network

Computation of Partially Inflated Shapes of Stratospheric Balloon Structures X. Deng and S between height, volume and stress distribution in a superpressure pumpkin balloon with the differential pressure applied to the balloon. Two different approaches are presented. A simple two-dimensional solution

Pellegrino, Sergio

303

Experts' understanding of partial derivatives using the Partial Derivative Machine  

E-print Network

Partial derivatives are used in a variety of different ways within physics. Most notably, thermodynamics uses partial derivatives in ways that students often find confusing. As part of a collaboration with mathematics faculty, we are at the beginning of a study of the teaching of partial derivatives, a goal of better aligning the teaching of multivariable calculus with the needs of students in STEM disciplines. As a part of this project, we have performed a pilot study of expert understanding of partial derivatives across three disciplines: physics, engineering and mathematics. Our interviews made use of the Partial Derivative Machine (PDM), which is a mechanical system featuring four observable and controllable properties, of which any two are independent. Using the PDM, we probed expert understanding of partial derivatives in an experimental context in which there is not a known functional form. Through these three interviews, we found that the mathematicians exhibited a striking difference in their underst...

Roundy, David; Dray, Tevian; Manogue, Corinne A; Weber, Eric

2014-01-01

304

Use of the intraosseous screw for unilateral upper molar distalization and found well balanced occlusion  

Microsoft Academic Search

BACKGROUND: The aim of this study was to present a temporary anchorage device with intraosseous screw for unilateral molar distalization to make a space for the impacted premolar and to found well balanced occlusion in a case. CASE PRESENTATION: A 13-year-old male who have an impacted premolar is presented with skeletal Class I and dental Class 2 relationship. The screw

Ibrahim Erhan Gelgor; Ali Ihya Karaman; Tamer Buyukyilmaz

2006-01-01

305

[Dental health of first molars among Westphalian immigrants and German students].  

PubMed

The aim of this study was to assess the health status of the occlusal surface on the first molars of Westphalian students, of whom 41.0% were immigrants. The prevalence and retention of fissure sealants (FS) and caries experience was scored for 161 students aged 8 and 10 years. Logistic regression analysis was used to predict the influence of sex, ethnicity, and retention of FS on the occlusal caries risk of the first molars. There was no difference in caries prevalence and experience in 8-year-old German students and immigrants (5.6%/10.5%; 0.07 DMFT/0.21 DMFT), both parameters were significantly higher in 10-year-old immigrants than in German students (25.5%/9.5%; 0.55 DMFT/0.11 DMFT). The prevalence and number of molars with FS was not different between German students and immigrants at 8 years (39.1%, 1.28 FS; 33.8%, 0.94 FS) and at 10 years of age (47.4%, 1.68 FS; 39.4%, 1.17 FS). The occlusal caries risk of first molars without FS was significantly higher in 8-year-old immigrants than in German students (OR 4.62). FS should be used more frequently in daily dental practice. To improve the quality of FS, stricter implementation of guideline-based standards is required. PMID:24297452

Heinrich-Weltzien, R; Walther, M; Goddon, I; Kühnisch, J

2014-01-01

306

Surface Ultrastructure of Rat Molar Teeth after Experimentally Induced Erosion and Attrition  

Microsoft Academic Search

Young Osborne-Mendel rats were given different diets for 6 weeks. Effects of soft and rough food as well as acidic sport drink on the lingual surfaces of first mandibular molars were studied. In addition, the effect of fluoride on erosion was examined. A Jeol JSM-35 scanning electron microscope was used to visualize tooth surface ultrastructure. Intact surfaces were found in

R. Sorvari; A. Pelttari; J. H. Meurman

1996-01-01

307

Surgical Removal of Fractured Endodontic Instrument in the Periapex of Mandibular First Molar  

PubMed Central

The purpose of this article is to present the surgical removal of a broken endodontic file from the periapical region of the distal root of a mandibular first molar. The methods of diagnosis and measurement of the distance of the instrument to the adjacent vital structures in the periapical region was done with simple means and in an economical manner.

Gandevivala, Adil; Parekh, Bandish; Poplai, Gaurav; Sayed, Aliya

2014-01-01

308

What molars contribute to an emerging understanding of lateral enamel formation in Neandertals vs. modern humans  

Microsoft Academic Search

Two hypotheses, based on previous work on Neandertal anterior and premolar teeth, are investigated here: (1) that estimated molar lateral enamel formation times in Neandertals are likely to fall within the range of modern human population variation, and (2) that perikymata (lateral enamel growth increments) are distributed across cervical and occlusal halves of the crown differently in Neandertals than they

Debbie Guatelli-Steinberg; Donald J. Reid

2008-01-01

309

Molar Functional Relations and Clinical Behavior Analysis: Implications for Assessment and Treatment  

ERIC Educational Resources Information Center

The experimental analysis of behavior has identified several molar functional relations that are highly relevant to clinical behavior analysis. These include matching, discounting, momentum, and variability. Matching provides a broader analysis of how multiple sources of reinforcement influence how individuals choose to allocate their time and…

Waltz, Thomas J.; Follette, William C.

2009-01-01

310

Apical root resorption of maxillary first molars after intrusion with zygomatic skeletal anchorage.  

PubMed

The aim of this study was to evaluate radiographically the apical root resorption of maxillary first molars after their intrusion was done using zygomatic miniplates as skeletal anchorage in open-bite cases. The study group comprised 16 consecutively treated open-bite cases who had received special titanium miniplates in their zygomatic bones for use as anchorage to apply orthodontic intrusive forces to the maxillary posterior region. The control group consisted of 16 patients, who were matched regarding age, sex, and treatment duration but who had undergone fixed orthodontic treatment without intrusion mechanics for molars. Tooth lengths were measured on pretreatment, and posttreatment panoramic radiographs of all patients and mesiobuccal and distobuccal roots of left and right maxillary first molars were measured on-screen using a software program. The difference between the pre- and posttreatment tooth lengths was defined as apical root resorption. Comparison of the differences in root resorption of the two groups using the t-test for independent samples showed a statistically significant difference (P = .004) only for mesial roots on the right side. But because the mean difference in apical root resorption was only 0.5 mm, it was concluded that the apical root resorption of maxillary first molars after intrusion was done using zygomatic skeletal anchorage was not clinically significant. PMID:16283814

Ari-Demirkaya, Arzu; Masry, Mazin Al; Erverdi, Nejat

2005-09-01

311

Modern human molar enamel thickness and enamel--dentine junction shape  

E-print Network

, Box 571197, Washington, DC 20057-1197, USA Accepted 28 April 2006 Archives of Oral Biology (2006) 51 thickness; Enamel cap area; Dentine area; Enamel--dentine junction (EDJ) length; EDJ shape; Fossil hominids were generated from molars sectioned bucco- lingually across mesial cusps. Enamel cap area, dentine

Smith, Tanya M.

312

Passive drainage through the vestibular oblique incision in impacted inferior third molar surgery: a preliminary study.  

PubMed

The aim of the present study was to clinically evaluate the variables pain, swelling and trismus when two different suture techniques were applied in surgery of impacted lower third molars. The sample comprised 20 patients of both genders participating in the clinical trial at the Division of Oral and Maxillofacial Surgery, with an indication for the removal of bilaterally impacted lower third molars. They were divided into test and control groups. Complete suture was performed on the free and attached gums in the control group and only on the attached gum of the oblique vestibular incision in the test group. The results showed that the fact that the drainage of fluid through the suture was not obliterated led to diminution of pain 48 hours after surgery. No statistically significant differences were observed in relation to swelling, which diminished gradually in both groups. As regards the variable trismus, the test group presented a greater mouth opening throughout the evaluation, being statistically significant at 7 days. The probing depth, three months postoperatively, was found to be greater in the control group. This difference reached statistical significance for the vestibular distal region of the adjacent second molar. It is concluded that the strategy of not suturing the free gum of the oblique vestibular incision in the extraction of impacted lower third molars leads to the diminution of immediate painful symptomatology, but has no influence on the swelling. PMID:18841747

Xavier, Ruth Lopes de Freitas; Vasconcelos, Belmiro Cavalcanti do Egito; Caubi, Antonio Figuereido; Porto, Gabriela Granja; Maurette, Marvis Allais

2008-01-01

313

Effects of molar mass, concentration and thermodynamic conditions on polymer-induced flow drag reduction  

Microsoft Academic Search

Drag reduction in Taylor flow of polystyrene solutions is investigated using a commercial rheometer equipped with a standard double-gap sample holder with axial symmetry. The dependence of drag reduction on various factors, including polymer molar mass, polymer concentration, and thermodynamic conditions is studied. Drag reduction induced by polystyrene in toluene is found to increase with increasing polymer concentration in the

Torgeir Nakken; Morten Tande; Bo Nyström

2004-01-01

314

Bilateral fusion of mandibular second molars with supernumerary teeth: case report  

Microsoft Academic Search

Fusion is a developmental anomaly characterized by the union of two adjacent teeth. In this article we report a rare case of bilateral fusion of permanent mandibular second molars with supernumerary teeth. The rarity with which this entity appears, along with its complex characteristics, often make it difficult to treat. The endodontic management of one tooth is described, as well

Eduardo Nunes; Ivaldo Gomes de Moraes; Paulo Márcio de Oliveira Novaes; Simone Maria Galvão de Sousa

2002-01-01

315

Evaluating success of autotransplantation of embedded/impacted third molars harvested using piezosurgery: a pilot study.  

PubMed

Abstract Objective. To evaluate the success of autogenous transplantation of embedded/impacted third molars harvested using piezosurgery. Materials and methods. This prospective pilot study enrolled 20 healthy patients with non-restorable first/second molars and a caries-free retrievable embedded/impacted third molar. Piezosurgery was used for removing inter-radicular bone at the recipient socket as well as for bone removal around the donor teeth. Results. After an average follow-up of 16.4 months (SD = 1.9), 18 cases were successful with formation of periodontal ligament around the teeth. One tooth was lost due to infection at 1 month. One patient was lost to follow-up. There was no root resorption or ankylosis in any of the cases. In six donor teeth with complete root formation, root canal treatment was carried out. All the remaining teeth responded positively with vitality testing. Conclusion. Piezosurgery is an effective device if embedded/impacted third molars are to be harvested for successful autogenous transplantation. PMID:24791608

Nagori, Shakil Ahmed; Jose, Anson; Bhutia, Ongkila; Roychoudhury, Ajoy

2014-11-01

316

Transforming Growth Factor-? Isoform Expression in Mature Human Healthy and Carious Molar Teeth  

Microsoft Academic Search

Transforming growth factor (TGF)- isoforms have been implicated in cellular signalling during tooth development and repair, but little is known of their cellular localisation or distribution within the dental tissues in the mature tooth. This study investigated the presence of TGF-1, 2 and 3 isoforms in tissues of sound and carious human molar teeth, to understand better the expression of

A. J. Sloan; H. Perry; J. B. Matthews; A. J. Smith

2000-01-01

317

Genetic and Environmental Molarity and Modularity of Cognitive Functioning in 2-Year-Old Twins.  

ERIC Educational Resources Information Center

Investigated genetic and environmental influences on the similarity and differences among five tests of cognitive abilities in 1,958 pairs of same-sex twins born in 1994 in the United Kingdom. Results suggest a developmental trend from modularity to molarity when considered in relation to multivariate genetic results later in life that show that…

Petrill, Stephen A.; Saudino, Kimberly S.; Wilkerson, Bessie; Plomin, Robert

2001-01-01

318

Selenium:mercury molar ratios in bullfrog and leopard frog tadpoles from the northeastern United States.  

PubMed

Vertebrates experience adverse effects from methylmercury, largely obtained through their food. Selenium has the potential to reduce the toxic effects of methylmercury (and vice versa). In this paper, we examine the selenium:mercury molar ratios in tadpoles (Lithobates sphenocephalus, Lithobates catesbeianus (formerly Rana), and a newly documented leopard frog species currently referred to as R. sp. nov.) and fully formed leopard frog metamorphs. There were no significant differences in metal levels between the two leopard frog species, and data were therefore combined. Selenium:mercury molar ratios varied from 19 to 38 for bullfrog tadpoles, from 16 to 330 for leopard frog tadpoles, and from 7 to 17 for leopard frog metamorphs. Leopard frog tadpoles with less than 45 days exposure to field conditions had significantly higher molar ratios than other tadpoles and leopard frog metamorphs. There were significant locational differences for the molar ratios of bullfrogs, and leopard frog tadpoles with more than 45 days of field exposure. At the sites where we were able to sample both leopard frog tadpoles and leopard frog metamorphs, there were significant differences between the two distinct life stages. Most of the variation in the ratio was accounted for by selenium levels, field sites, and exposure period. PMID:24585386

Burger, Joanna; Feinberg, Jeremy; Jeitner, Christian; Gochfeld, Michael; Donio, Mark; Pittfield, Taryn

2014-06-01

319

Extension Rates and Growth in Tooth Height of Modern Human and Fossil Hominin Canines and Molars  

Microsoft Academic Search

The aim of this study was to describe similarities and differences in the way modern and fossil hominin teeth grow in height. Measurements from longitudinal ground sections of 7 modern human canines and 19 first permanent molars were used to calculate extension rates in the crowns and roots and to plot distance curves for growth in tooth height. These were

Christopher Dean

2009-01-01

320

Regaining leeway space and anterior crossbite correction with a modified maxillary molar distalizing appliance.  

PubMed

During the mixed dentition stage, adolescents experience rapid dental and skeletal development. Unfortunately, many of them do not visit the orthodontist early enough and miss out on the opportunity to take advantage of preventive and interceptive orthodontic treatment. This article describes the management of regaining leeway space and correcting anterior crossbite using a modified maxillary molar distalizing appliance. PMID:23855181

Park, J H; Tai, K; Ikeda, M; Kanao, A

2013-01-01

321

Endodontic management of a mandibular second molar with radix entomolaris: a case report  

PubMed Central

The presence of radix entomolaris (RE) in a mandibular first molar is a common occurrence in certain ethnic groups, but the presence of RE in a mandibular second molar is a rare occurrence. In the present case, RE was identified from preoperative radiographs and confirmed using cone-beam computed tomography (CBCT). The access cavity was modified to locate the RE. Cleaning and shaping were performed with nickel-titanium rotary instruments. Obturation was completed with gutta-percha cones using AH Plus (Dentsply Detrey GmbH) as sealer. From the CBCT axial images, the RE was determined to have a Type III curvature by the De Moor classification, Type B separate RE by the Carlsen and Alexandersen classification, and radiographically, a Type i image by the Wang classification. The presence of RE in the mandibular second molar makes it essential to anticipate and treat the distolingual root canal. This case report highlights the usefulness of CBCT for assessing RE in the mandibular second molar, which can help the clinician in making a confirmatory diagnosis and assessing the morphology of the root canal. PMID:24790927

Kandaswamy, Deivanayagam; Jayaprakash, Nachimuthu

2014-01-01

322

Variation in hominoid molar enamel thickness Tanya M. Smith a,*, Anthony J. Olejniczak a  

E-print Network

Evolution 48 (2005) 575e592 #12;taxonomic discrimination using enamel thickness, tooth type and sectionVariation in hominoid molar enamel thickness Tanya M. Smith a,*, Anthony J. Olejniczak a , Lawrence.K. Received 25 August 2004; accepted 16 February 2005 Abstract Enamel thickness has figured prominently

Smith, Tanya M.

323

Study of the chemical nature of petroleum components of high molar mass from Russian fields  

Microsoft Academic Search

Study of the composition and structure of high molar mass compounds (HMC) of petroleum may be simplified considerably by fractionation before physical and chemical analysis. Solvent extraction, adsorption, gel-filtration, ion-exchange chromatography and other methods are applied to this end, the first two methods are most popular. The separation of resins by extraction is restricted as these petroleum components readily dissolve

T. A. Filimonova; L. V. Gorbunova; V. F. Kamyanov

1984-01-01

324

Femto-Molar Sensitive Field Effect Transistor Biosensors Based on Silicon Nanowires and  

E-print Network

Femto-Molar Sensitive Field Effect Transistor Biosensors Based on Silicon Nanowires and Antibodies-- This article presents electrically-based sensors made of high quality silicon nanowire field effect transistors characterizing the early stage of the diseases. Devices like field-effect transistors (FETs) can be suitable can

Dalang, Robert C.

325

Simultaneous determination of interfacial molarities of amide bonds, carboxylate groups, and water by chemical trapping in micelles of amphiphiles containing peptide bond models.  

PubMed

Chemical trapping is a powerful approach for obtaining experimental estimates of interfacial molarities of weakly basic nucleophiles in the interfacial regions of amphiphile aggregates. Here, we demonstrate that the chemical probe 4-hexadecyl-2,6-dimethylbenzenediazonium ion (16-ArN(2)(+)) reacts competitively with interfacial water, with the amide carbonyl followed by cleavage of the headgroups from the tail at the amide oxygen, and with the terminal carboxylate groups in micelles of two N-acyl amino-acid amphiphiles, sodium N-lauroylsarcosinate (SLS) and sodium N-lauroylglycinate (SLG), simple peptide bond model amphiphiles. Interfacial molarities (in moles per liter of interfacial volume) of these three groups were obtained from product yields, assuming that selectivity toward a particular nucleophile compared to water is the same in an aqueous reference solution and in the interfacial region. Interfacial carboxylate group molarities are ~1.5 M in both SLS and SLG micelles, but the concentration of the amide carbonyl for SLS micelles is ~4.6-5 times less (ca. 0.7 M) than that of SLG micelles (~3 M). The proton on the secondary N of SLG helps solubilize the amide bond in the aqueous region, but the methyl on the tertiary N of SLS helps solubilize the amide bond in the micellar core, reducing its reaction with 16-ArN(2)(+). Application of chemical trapping to proteins in membrane mimetic interfaces should provide insight into the topology of the protein within the interface because trapping of the amide carbonyl and cleavage at the C-N bond occurs only within the interface, and fragment characterization marks those peptide bonds located within the interface. PMID:23237147

Zhang, Yongliang; Romsted, Laurence S; Zhuang, Lanzhen; de Jong, Sander

2013-01-15

326

Isotropic finite volume discretization  

NASA Astrophysics Data System (ADS)

Finite volume methods traditionally employ dimension by dimension extension of the one-dimensional reconstruction and averaging procedures to achieve spatial discretization of the governing partial differential equations on a structured Cartesian mesh in multiple dimensions. This simple approach based on tensor product stencils introduces an undesirable grid orientation dependence in the computed solution. The resulting anisotropic errors lead to a disparity in the calculations that is most prominent between directions parallel and diagonal to the grid lines. In this work we develop isotropic finite volume discretization schemes which minimize such grid orientation effects in multidimensional calculations by eliminating the directional bias in the lowest order term in the truncation error. Explicit isotropic expressions that relate the cell face averaged line and surface integrals of a function and its derivatives to the given cell area and volume averages are derived in two and three dimensions, respectively. It is found that a family of isotropic approximations with a free parameter can be derived by combining isotropic schemes based on next-nearest and next-next-nearest neighbors in three dimensions. Use of these isotropic expressions alone in a standard finite volume framework, however, is found to be insufficient in enforcing rotational invariance when the flux vector is nonlinear and/or spatially non-uniform. The rotationally invariant terms which lead to a loss of isotropy in such cases are explicitly identified and recast in a differential form. Various forms of flux correction terms which allow for a full recovery of rotational invariance in the lowest order truncation error terms, while preserving the formal order of accuracy and discrete conservation of the original finite volume method, are developed. Numerical tests in two and three dimensions attest the superior directional attributes of the proposed isotropic finite volume method. Prominent anisotropic errors, such as spurious asymmetric distortions on a circular reaction-diffusion wave that feature in the conventional finite volume implementation are effectively suppressed through isotropic finite volume discretization. Furthermore, for a given spatial resolution, a striking improvement in the prediction of kinetic energy decay rate corresponding to a general two-dimensional incompressible flow field is observed with the use of an isotropic finite volume method instead of the conventional discretization.

Shukla, Ratnesh K.; Giri, Pritam

2014-11-01

327

Accelerated partial breast irradiation.  

PubMed

Local therapies to treat newly diagnosed breast cancer include a lumpectomy with radiation therapy or a mastectomy. The 20-year data from studies about the safety and efficacy of lumpectomy with full-breast radiation therapy support the safety of this regimen and its role to decrease the risk of ipsilateral recurrence and increase long-term survivorship of women with breast cancer. Accelerated partial breast irradiation (APBI) provides radiation therapy to the tumor bed but spares the remaining breast tissue. APBI accelerates the time required to complete the therapy regimen, with a range of one intraoperative session to five consecutive days compared to five to seven weeks. Several techniques exist to administer APBI, including the insertion of a balloon into the lumpectomy space. Of interest is the widespread use of APBI in community and academic settings that has preceded outcomes of large, randomized clinical trials. Because of selection bias in a number of small, single-institution, nonrandomized studies, published data are of limited value to ensure APBI as a standard of care. PMID:25253109

Bauer, Elfrida; Lester, Joanne L

2014-10-01

328

Partial oxidation process  

SciTech Connect

A continuous process for preventing the build-up of metals from the hydrocarbonaceous fuel feed in a partial oxidation system in which about 80-100 wt. % of the carbon-soot produced is recycled to the gas generator. By the subject process a significantly large portion of the metals and metal compounds i.e. ash in the soot-water feed stream to the decanter become concentrated in the grey water that separates out in the decanter in the carbon recovery section. The concentration of ash suspended in the grey water may be then easily reduced in a solids-liquid separator with or without the addition of a flocculant and prior to recycling a portion of the grey water to the gas quench tank and/or gas scrubber. Further, the ash suspended in the carbon-soot-liquid hydrocarbonaceous fuel stream from the bottom of the liquid organic extractant still may be optionally reduced in another solids-liquid separator prior to recycling a portion of said stream to the gas generator as part of the hydrocarbonaceous reactant fuel feed.

Dille, R.M.; Estabrook, L.E.; Rhodes, H.A.; Richter, G.N.; Rohner, J.G.P.

1984-08-21

329

Mobilities of organic compounds in plant cuticles as affected by structure and molar volumes of chemicals and plant species  

Microsoft Academic Search

Solute mobilities of 28 compounds in isolated cuticular membranes (CM) from Capsicum annuum L. fruit, Citrus aurantium L. and Pyrus communis L. leaves were studied using unilateral desorption from the outer surface. First-order rate constants of desorption (k*), which are directly proportional to the diffusion coefficient in the waxy outer limiting skins of cuticles were measured. When log k* was

Peter Baur; Hend Marzouk; Jörg Schönherr; Hubert Bauer

1996-01-01

330

SEGMENTATION STRATEGIES FOR POLYMERIZED VOLUME DATA SETS PURNA DODDAPANENI  

E-print Network

SEGMENTATION STRATEGIES FOR POLYMERIZED VOLUME DATA SETS A Thesis by PURNA DODDAPANENI Submitted FOR POLYMERIZED VOLUME DATA SETS A Thesis by PURNA DODDAPANENI Submitted to Texas A&M University in partial Strategies for Polymerized Volume Data Sets (December 2004) Purna Chandra Rao Doddapaneni, B.Tech., Indian

331

STRATEGY FOR CONSTRUCTION OF POLYMERIZED VOLUME DATA SETS  

E-print Network

and validation of the resulting PVDS is shown in both cases. #12;iv Finally the procedures of polymerized volumeSTRATEGY FOR CONSTRUCTION OF POLYMERIZED VOLUME DATA SETS A Thesis by PRATHYUSHA ARAGONDA Submitted OF POLYMERIZED VOLUME DATA SETS A Thesis by PRATHYUSHA ARAGONDA Submitted to Texas A&M University in partial

332

Comparing Volumes  

NSDL National Science Digital Library

The purpose of this lab is to investigate volume (capacity). Using multiplicative comparisons, students will try to predict how many times the amount of water of one container will fit in another container.

2011-01-01

333

Trigonometric Integrals via Partial Fractions  

ERIC Educational Resources Information Center

Parametric differentiation is used to derive the partial fractions decompositions of certain rational functions. Those decompositions enable us to integrate some new combinations of trigonometric functions.

Chen, H.; Fulford, M.

2005-01-01

334

Age at first molar emergence in early Miocene Afropithecus turkanensis and life-history evolution in the Hominoidea  

E-print Network

the life histories of fossil primate species. One method of determining age at first molar emergence is to determine the age at death of fossil individuals that were in the process of erupting their first molars enamel perikymata with estimates of the duration of cuspal enamel formation and the duration

Smith, Tanya M.

335

Low Temperature Heat Capacities and Standard Molar Enthalpy of Formation of 2-Pyrazinecarboxylic Acid (C5H4N2O2)(s).  

PubMed

Low-temperature heat capacities of 2-pyrazinecarboxylic acid (C5H4N2O2)(s) were measured by a precision automated adiabatic calorimeter over the temperature range from 78 to 400 K. A polynomial equation of heat capacities as a function of temperature was fitted by least squares method. Based on the fitted polynomial, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated and tabulated at 10 K intervals. The constant-volume energy of combustion of the compound at T = 298.15 K was measured by a precision rotating-bomb combustion calorimeter to be ?cU = -(17839.40 ± 7.40) J g-1. The standard molar enthalpy of combustion of the compound was determined to be ?cH0m = -(2211.39 ± 0.92) KJ mol-1, according to the definition of combustion enthalpy. Finally, the standard molar enthalpy of formation of the compound was calculated to be ?fH0m = -(327.82 ± 1.13) kJ mol-1 in accordance with Hess law. PMID:24061733

Kong, Yu-Xia; Di, You-Ying; Yang, Wei-Wei; Gao, Sheng-Li; Tan, Zhi-Cheng

2010-06-01

336

GENERAL: Low-temperature heat capacities and standard molar enthalpy of formation of 4-(2-aminoethyl)-phenol (C8H11NO)  

NASA Astrophysics Data System (ADS)

This paper reports that low-temperature heat capacities of 4-(2-aminoethyl)-phenol (C8H11NO) are measured by a precision automated adiabatic calorimeter over the temperature range from 78 to 400 K. A polynomial equation of heat capacities as a function of the temperature was fitted by the least square method. Based on the fitted polynomial, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated and tabulated at the interval of 5 K. The energy equivalent, ?calor, of the oxygen-bomb combustion calorimeter has been determined from 0.68 g of NIST 39i benzoic acid to be ?calor = (14674.69±17.49)J.K-1. The constant-volume energy of combustion of the compound at T = 298.15 K was measured by a precision oxygen-bomb combustion calorimeter to be ?cU = -(32374.25±12.93)J.g-1. The standard molar enthalpy of combustion for the compound was calculated to be ?cHmominus = -(4445.47 ± 1.77) k. J · mol-1 according to the definition of enthalpy of combustion and other thermodynamic principles. Finally, the standard molar enthalpy of formation of the compound was derived to be ?fHmominus(C8H11NO, s) = -(274.68 ± 2.06) kJ · mol-1, in accordance with Hess law.

Di, You-Ying; Kong, Yu-Xia; Yang, Wei-Wei; Tan, Zhi-Cheng

2008-09-01

337

A modified device for intraoral radiography to assess the distal osseous defects of mandibular second molar after impacted third molar surgery  

PubMed Central

Purpose This article is to describe a modified device for intraoral radiography which was developed to obtain reproducible radiographic images for assessment of distal osseous defects of the mandibular second molar (2 Mm) after impacted third molar (3 Mm) surgery. Materials and Methods A commercial available alignment system for posterior region was modified by adding a reference gauge pin (millimetric) and threading a hollow acrylic cylinder at the ring of the radiographic positioner to attach the X-ray collimator. The design included customized resin acrylic stent for the occlusal surface of the 2Mm in maximum intercuspal position, individualizing the biteblock positioner. Periapical radiographs were taken before and after surgical extraction of 3 Mm, employing the radiographic technique of parallelism described by Kugelberg (1986) with this modified film holder and inserting the gauge pin on the deepest bone probing depth point. Results This technique permitted to obtain standardized periapical radiographs with a moderate to high resolution, repeatability, and accuracy. There was no difference between the measurements on the pre- and post-operative radiographs. This technique allowed better maintenance of the same geometric position compared with conventional one. The insertion of the gauge pin provided the same reference point and localized the deepest osseous defect on the two-dimensional radiographs. Conclusion This technique allowed better reproducibility in posterior radiographic records (distal surface of 2 Mm) and more accurate measurements of radiographic bone level by the use of a millimetric pin. PMID:22010068

Ana, Faria-Inocencio

2011-01-01

338

Volumetric, ultrasonic speed, and viscometric studies of salbutamol sulphate in aqueous methanol solution at different temperatures  

Microsoft Academic Search

Values of density, ultrasonic speed, and viscosity of salbutamol sulphate (SBS) have been determined in aqueous methanol solutions at T=(303.15, 308.15, 313.15, and 318.15)K. The apparent molar volume V?, partial molar volume V?0, molar expansivity E20, isobaric thermal expansion coefficient (?2), and second derivative of infinite dilution of partial molar volume with temperature ?2V?0\\/?T2 are evaluated using density data. Isentropic

K. Rajagopal; S. S. Jayabalakrishnan

2010-01-01

339

Molar Uprighting  

MedlinePLUS

... that this be done before a bridge or implant replaces the missing tooth. Preparation Before any treatment ... However, if you will be getting a dental implant, your dentist may want it put in before ...

340

Crystallization behavior of bisphenol-A polycarbonate: Effects of crystallization time, temperature, and molar mass  

NASA Astrophysics Data System (ADS)

Crystallization and multiple melting behavior of bisphenol-A polycarbonate (PC) was investigated using differential scanning calorimetry (DSC) for the monitoring of thermal behavior and atomic force microscopy (AFM) for the morphology study. The exceedingly slow crystallization kinetics of PC and the feasibility of obtaining near monodisperse fractions provide distinct advantages for the elucidation of the effects of crystallization time, temperature, and molar mass on crystallization kinetics. The effects of molar mass on the glass transition temperature (T g) and heat capacity change at Tg, and the amorphous density of PC were investigated. Similar to many semicrystalline polymers, PC exhibits a multiple melting behavior upon heating. While for each PC sample, the coexistence of low and high temperature endothermic regions in the DSC heating traces is explained by the melting of populations of crystals with different stabilities, melting-recrystallization-remelting effects are observed only for the lowest molar mass samples. The effects of crystallization temperature and molar mass distribution on overall crystallization kinetics were studied for some of the fractions, including the commercial PC-28K (Mw = 28,000 g.mol-1 ) sample. Regarding the kinetics of secondary crystallization, particular attention was placed on understanding the effects of molar mass, initial degree of crystallinity prior to the secondary crystallization, and secondary crystallization time and temperature. The secondary crystallization of PC follows the same laws discovered in previous studies of PEEK, PET, it-PS and ethylene copolymers, and the results are discussed in the context of a bundle-like secondary crystallization model. During isothermal annealing of semicrystalline PC-28K around the high melting endotherm, a significant increase of melting temperature along with peak broadening with time was observed. Independently, morphological studies using AFM showed that mean lamellar thickness increases with time during isothermal annealing. These results are discussed in light of isothermal thickening of lamellar crystals. Lastly, almost 200 DSC melting traces of varying molar mass PC samples thermally treated under various conditions were analyzed to calculate crystallinity (Xc), rigid fraction (RF), and rigid amorphous fraction (RAF). The correlation between RAF vs Xc, Tg, and Tg broadening are discussed.

Sohn, Seungman

341

The Annotated Mina, Volume Two  

E-print Network

1 Mina de Malfois Volume Two Disclaimer: This is a work of fiction. No resemblance is intended to any person or persons living, dead, or online. No BNFs were harmed in the making of this fic. Permissions: These stories... and characters are the sole property of the author, but she lends them out for fanfic and fanart. A partial list of Mina de Malfois/Sanguinity things by other people can be found at the back of this volume. For further Minaverseness, try tracking down...

2014-03-10

342

Partial reinforcement in the turtle  

Microsoft Academic Search

Two matched groups of young turtles, Pseudemys scripta elegans, were trained in a simple runway, one with partial and the other with consistent reinforcement, following which both were extinguished. The two groups did not differ significantly in resistance to extinction. This finding constitutes further evidence against the hypothesis that the paradoxical effect of partial reinforcement which is found in higher

Rochelle M. Eskin; M. E. Bitterman

1961-01-01

343

Marginal adaptation of different types of all-ceramic partial coverage restorations after exposure to an artificial mouth  

Microsoft Academic Search

Objectives To determine the influence of the preparation design and the dimensions of all-ceramic partial coverage restorations (PCR) on the marginal accuracy before and after masticatory simulation.Methods In this in vitro study 80 extracted human maxillary molars were restored with MOD inlay restorations and four different modified PCR restorations using a new press ceramic IPS e.max® Press (IPS e.max® Press

N Denner; T Gerds; J R Strub; C F J Stappert

2005-01-01

344

Partial Pressures of Te2 and Thermodynamic Properties of Ga-Te System  

NASA Technical Reports Server (NTRS)

The partial pressures of Te2 in equilibrium with Ga(1-x)Te(x) samples were measured by optical absorption technique from 450 to 1100 C for compositions, x, between 0.333 and 0.612. To establish the relationship between the partial pressure of Te, and the measured optical absorbance, the calibration runs of a pure Te sample were also conducted to determine the Beer's Law constants. The partial pressures of Te2 in equilibrium with the GaTe(s) and Ga2Te3(s)compounds, or the so-called three-phase curves, were established. These partial pressure data imply the existence of the Ga3Te4(s) compound. From the partial pressures of Te2 over the Ga-Te melts, partial molar enthalpy and entropy of mixing for Te were derived and they agree reasonable well with the published data. The activities of Te in the Ga-Te melts were also derived from the measured partial pressures of Te2. These data agree well with most of the previous results. The possible reason for the high activity of Te measured for x less than 0.60 is discussed.

Su, Ching-Hua; Curreri, Peter A. (Technical Monitor)

2001-01-01

345

[Evaluation of cermet fillings in abutment teeth in removable partial prostheses].  

PubMed

The aim of the study was to describe the clinical process of setting the purpose filling on abutment teeth, after finishing the removable partial dentures. The aim was also to investigate the use of cermet glass-ionomer cement for the purpose filling in the abutment teeth for removable partial dentures, as well as to investigate the surface of the purpose filling. For the clinical evaluation of purpose filling slightly modified criteria according to Ryg's were used in 20 patients with different type of edentulousness. Changes occurring on the surface of purpose filling have been experimentally established by the method of scanning electron microscopy on the half-grown third molars in seven patients. It could be concluded that cement glass-ionomer was not the appropriate material for the purpose fillings in abutment teeth for removable partial dentures. PMID:11858021

Saulic, S; Tihacek-Sojic, Lj

2001-01-01

346

Unusual treatment of bimaxillary dentoalveolar protrusion via miniscrews and molar extraction  

PubMed Central

This case report describes the treatment of a Saudi female patient, aged 13 years 8 months at the start of treatment, with a Class I bimaxillary dentoalveolar protrusion and extracted maxillary first molars. Miniscrews were placed bilaterally in the interdental space between both the upper and the lower posterior teeth. The treatment plan consisted of extraction of both lower first permanent molars, distalization of upper and lower premolars using miniscrews followed by en masse retraction of the upper and lower six anterior teeth. The active treatment period was 2 years 8 months. Arch retention was done using upper wrap-around retainer and lower fixed 3-3 retainer. The use of miniscrews helped to resolve the bimaxillary protrusion regardless of extraction pattern used. PMID:24987626

Al-Fraidi, Ahmad; Afify, Ahmed R.

2012-01-01

347

Unusual treatment of bimaxillary dentoalveolar protrusion via miniscrews and molar extraction.  

PubMed

This case report describes the treatment of a Saudi female patient, aged 13 years 8 months at the start of treatment, with a Class I bimaxillary dentoalveolar protrusion and extracted maxillary first molars. Miniscrews were placed bilaterally in the interdental space between both the upper and the lower posterior teeth. The treatment plan consisted of extraction of both lower first permanent molars, distalization of upper and lower premolars using miniscrews followed by en masse retraction of the upper and lower six anterior teeth. The active treatment period was 2 years 8 months. Arch retention was done using upper wrap-around retainer and lower fixed 3-3 retainer. The use of miniscrews helped to resolve the bimaxillary protrusion regardless of extraction pattern used. PMID:24987626

Al-Fraidi, Ahmad; Afify, Ahmed R

2012-04-01

348

Molar Growth Yields of Certain Lactic Acid Bacteria as Influenced by Autolysis  

PubMed Central

Molar growth yields determined from batch cultures of Streptococcus diacetilactis and S. faecalis were appreciably greater at the peaks of maximal growth than after continued incubation and considerable autolysis. The higher molar growth yields were about equal to those determined in a continuous culture. Autolysis during logarithmic growth was minimal. The average Y value for adenosine triphosphate (ATP), determined by using limiting concentrations of glucose, galactose, lactose, and maltose for growing S. diacetilactis and limiting concentrations of glucose for growing S. lactis, S. cremoris, and S. faecalis, was 17.0. This is close to the Y (arginine) value of 17.8 determined with S. faecalis, but 62% greater than the generally accepted value of 10.5. Data are presented indicating that the often-used Y (ATP) value of 10.5 is erroneously low. PMID:4969603

Moustafa, Hassan H.; Collins, E. B.

1968-01-01

349

Aneurysmal bone cyst of maxilla with ectopic molar tooth - a case report.  

PubMed

Aneurysmal cysts of bone are rare non-neoplastic, locally aggressive lesion of bone with propensity for rapid growth, affecting mainly the long bones and spine. It rarely occurs in the head and neck region and within the head and neck mandible (especially the molar areas) is common. Aneurysmal cyst of bone involving the maxilla in the first decade of life is even rarer. We report a case of giant aneurysmal bone cyst of maxilla in eight-year-old male with ectopic molar tooth within the cyst. Is endoscopic excision possible? Endoscopic excision of the cyst was done successfully and no recurrence was noted even after 1 year of follow up. PMID:24238115

Verma, Roshan Kumar; Kumar, Ram; Bal, Amanjeet; Panda, Naresh K

2013-01-01

350

Radicular cyst associated with a primary first molar: A case report  

PubMed Central

Radicular cysts arising from deciduous teeth are rare. This report presents a case of radicular cyst associated with a primary molar following pulp therapy and discusses the relationship between pulp therapy and the rapid growth of the cyst. The treatment consisted of enucleation of the cyst sac and extraction of the involved primary teeth and 20 months follow up of the patient. Early diagnosis of the lesion would have lead to a less aggressive treatment plan. PMID:22509461

Toomarian, L.; Moshref, M.; Mirkarimi, M.; Lotfi, A.; Beheshti, M.

2011-01-01

351

Electrical Conductance of Fissure Enamel in Recently Erupted Molar Teeth as Related to Caries Status  

Microsoft Academic Search

Pit-and-fissure caries lesions contribute greatly to the caries incidence in permanent molar teeth in children. To date, the diagnosis of occlusal caries is still performed mainly by visual inspection, periodically aided by bite-wing radiography. However, in detecting small occlusal carious lesions, these methods perform inadequately, especially in low caries prevalence populations or individuals. The use of electrical conductance measurements (ECMs)

Y. L. Ie; E. H. A. M. Verdonschot; M. J. M. Schaeken; M. A. van’t Hof

1995-01-01

352

Study of transient photorefractive beam coupling in high- and low-molar-mass liquid crystal mixtures  

NASA Astrophysics Data System (ADS)

We observed transient signals of Bragg grating formation in high-performance photorefractive high- and low-molar-mass liquid crystal mixtures (HL-LCMs). These transient signals including oscillation-like behavior can be explained by a complex time constant in the case of a finite applied dc field. The time constant for the space-charge field to reach its steady state and the oscillation frequency are estimated.

Ono, H.; Kawatsuki, N.

353

Engineered Struvite Precipitation: lmpacts of Gomponent-lon Molar Ratios and pH  

Microsoft Academic Search

Struvite Fecipitation has the potential for rcmoving and recovering phosphorus from agricultural wastewater streams, such as concentrated animal feeding operations wastewater. However, impacts of anticipated component-ion molar ratios and potentially inter- fering ions are unknown as are the compounding pH relationship with respect to all potential complexes. This research expe.imentally investigates and mathematically models these facto.s. Emphasis is placed upon

Jun Wangl; Joel G. Burken; Rao Surampalli

354

Strategies used to inhibit postoperative swelling following removal of impacted lower third molar  

PubMed Central

Postoperative swelling following different surgical strategies is an area of great interest. The main part of literature on the topic deals with swelling after extraction of low impacted third molar. In this review, we have analyzed publications of the last 20 years with a pubmed search using the following key words: impacted third molar, swelling third molar, wisdom tooth, edema jaw, corticosteroids and extraction third molar, antibiotic prophylaxis and tooth extraction. Attention has often been focused on corticosteroid therapy administered by diverse routes (orally, IV, IM, topically) and at different time schedules (before or after surgery or both). This investigation revealed how the use of different molecules and dosages makes the obtained results hardly comparable. Similar conclusions can be drawn from studies aimed at evaluating the efficacy of antibiotic therapy administered either before or after surgery. A complete review has also to take into account different surgical strategies used including various flaps, no traumatic osteothomy, and primary or secondary closure. The use of pharmacological therapy and application of an ice pack is critical in the postoperative period and has always provided positive results. However, even if it is difficult to come to definite conclusions, due to the variability of the design of studies analyzed, the postoperative discomfort identified with edema, pain and trismus following wisdom tooth removal is influenced by various factors such as the difficulty of the surgical procedure involved, age and gender of the patient, and experience of the surgeon. The pharmacological therapy when performed with corticosteroids seems to improve control of the postoperative swelling related with this kind of surgeries. PMID:22135686

Sortino, Francesco; Cicciu, Marco

2011-01-01

355

Maxillary Molar Extraction Decreases Stiffness of the Mandible in Ovariectomized Rats  

Microsoft Academic Search

Although osteoporosis is a major public health concern, the effect of this condition on oral bone has not been determined. Using the ovariectomized rat as a model, we examined whether acute estrogen depletion affects the mandible of the ovariectomized rat with and without maxillary molar extraction. Twenty-two ovariectomized and 20 sham-ovariectomized 90-day-old Sprague-Dawley rats were divided into the following groups:

R. P. Elovic; J. A. Hipp; W. C. Hayes

1994-01-01

356

Poly(4-vinylpyridine isopentyl bromide) as inhibitor for corrosion of pure iron in molar sulphuric acid  

Microsoft Academic Search

The effect of poly(4-vinylpyridine isopentyl bromide) (P4VPIPBr) in three degrees of quaternisation (6, 18 and 79%) on the corrosion of pure iron in molar sulphuric acid is investigated by potentiodynamic, polarisation resistance and weight loss measurements. The inhibition efficiency (E%) of P4VPIPBr increases with its concentration to attain ?100% around 5×10?6M. E% values obtained from the various methods are in

A Chetouani; K Medjahed; K. E Benabadji; B Hammouti; S Kertit; A Mansri

2003-01-01

357

A Clinical Trial of Pulpotomy vs. Root Canal Therapy of Mature Molars  

Microsoft Academic Search

Root canal therapy (RCT) and tooth extraction are the main treatment options for irreversible pulpitis or its sequelae. Pulpotomy is an alternative treatment; however, more evidence is required. If outcomes of pulpotomy with a calcium-enriched mixture (PCEM) are non-inferior for mature molars with irreversible pulpitis compared with those from one-visit RCT (ORCT), this may be a beneficial treatment option. Four

S. Asgary; M. J. Eghbal

2010-01-01

358

Tree fine root Ca\\/Al molar ratio – Indicator of Al and acidity stress  

Microsoft Academic Search

High soil acidity and elevated soil Al concentrations limit plant growth in many terrestrial ecosystems. Aluminium toxicity can be ameliorated by Ca. Thus, Ca\\/Al molar ratios in soil solution and in plant tissues have been proposed as superior indicators than Al concentration itself for evaluating the Al toxicity stress to trees (Cronan & Grigal, J Environ Qual 1995;24:209 – 226). This article

E. I. Vanguelova; Y. Hirano; T. D. Eldhuset; L. Sas-Paszt; M. R. Bakker; Ü. Püttsepp; I. Brunner; K. Lõhmus; D. Godbold

2007-01-01

359

Glucose Degradation, Molar Growth Yields, and Evidence for Oxidative Phosphorylation in Streptococcus agalactiae  

PubMed Central

In a complex medium with the energy source as the limiting nutrient factor and under anaerobic growth conditions, Streptococcus agalactiae fermented 75% of the glucose to lactic acid and the remainder to acetic and formic acids and ethanol. By using the adenosine triphosphate (ATP) yield constant of 10.5, the molar growth yield suggested 2 moles of ATP per mole of glucose from substrate level phosphorylation. Under similar growth conditions, pyruvate was fermented 25% to lactic acid, and the remainder was fermented to acetic and formic acids. The molar growth yield suggested 0.75 mole of ATP per mole of pyruvate from substrate level phosphorylation. Under aerobic growth conditions about 1 mole of oxygen was consumed per mole of glucose; about one-third of the glucose was converted to lactic acid and the remainder to acetic acid, acetoin, and carbon dioxide. Molar growth yields indicated 5 moles of ATP per mole of glucose. Estimates based on products of glucose degradation suggested that about one-half of the ATP was derived from substrate level phosphorylation and one-half from oxidative phosphorylation. Addition of 0.5 m 2,4-dinitrophenol reduced the growth yield to that occurring in the absence of oxygen. Aerobic pyruvate degradation resulted in 30% of the substrate becoming reduced to lactic acid and the remainder being converted to acetic acid and carbon dioxide, with small amounts of formic acid and acetoin. The molar growth yields and products found suggested that 0.70 mole of ATP per mole of pyruvate resulted from substrate level phosphorylation and 0.4 mole per mole of pyruvate resulted from oxidative phosphorylation. PMID:4550679

Mickelson, M. N.

1972-01-01

360

C-Shaped Canal in Maxillary First Molars: A Case Report  

PubMed Central

C-shaped configuration in the upper maillary first molar is an extremely rare appearance (0.12%). This case reports management of the tooth with such a configuration as well as depiction of its internal morpholgy and external morphology through spiral computed tomography and dentascan in the contralateral tooth with similar morphology. After careful clinical observation and confirmation through spiral computed tomography, it was concluded that the teeth had Melton category I configuration with fused roots. PMID:24910684

Joshi, Chintan; Joshi, Surabhi

2014-01-01

361

Histopathological and radiographic evaluation of rat molar teeth after traumatic injury-a pilot study  

PubMed Central

Objective: Radiographic and histopathological evaluation of mechanical trauma on the development of maxillary molars in rat. Materials and Methods: Experimental study with 7-day-old five new born Wistar rats. Trauma induced on 7th postnatal day with #55 K file. Right first molar region of the maxilla was the experimental side, and the left side as control. Each animal was sacrificed for histopathological observation on 8th day (immediately next day of injury), 10th day (after 3 days of injury), 13th day (Enamel completion), 19th day (Emergence into oral cavity) and 42nd day when all the teeth came into functional occlusion. Results: On the 42nd day experimental side of the study, the 1st molar tooth had not erupted and the radiographs taken revealed conglomerate mass suggestive of complex odontome. Reduced tooth size, altered enamel and dentin formation, abscess formation and complex odontome like structure were observed histopathologically. Conclusion: The diversity of morphlogical and histopathological changes to intrusive force implies intricate mechanism involved in tooth development. PMID:23248457

Prasanth, T; Saraswathi, TR

2012-01-01

362

Molar mass of silicon highly enriched in 28Si determined by IDMS  

NASA Astrophysics Data System (ADS)

The molar mass of a new silicon crystal material highly enriched in 28Si ('Si28', x(28Si) >99.99%) has been measured for the first time using a combination of a modified isotope dilution mass spectrometry (IDMS) technique and a high resolution multicollector-ICP-mass spectrometer. This work is related to the redetermination of the Avogadro constant NA with an intended relative measurement uncertainty urel(NA) <= 2 × 10-8. The corresponding experimental investigations of the International Avogadro Coordination (IAC) were performed using this novel 'Si28' material. One prerequisite of the redetermination of NA is the determination of the isotopic composition and thus molar mass of 'Si28' with urel(M('Si28')) <= 1 × 10-8. At PTB, a molar mass M('Si28') = 27.976 970 27(23) g mol-1 has been determined with an associated relative uncertainty urel(M('Si28')) = 8.2 × 10-9, opening the opportunity to reach the target uncertainty of NA.

Pramann, Axel; Rienitz, Olaf; Schiel, Detlef; Schlote, Jan; Güttler, Bernd; Valkiers, Staf

2011-04-01

363

The use of resin-based composite restorations in pulpotomized primary molars.  

PubMed

The purpose of this retrospective clinical study was to report a 12- to 54-month follow-up, in which a resin-based composite filling material was used in direct contact with a fast-setting zinc oxide eugenol cement to restore the function and anatomy of 51 pulpotomized primary molars in 2- to 11-year-old children who needed a Class I or II restoration. Formocresol pulpotomy using Temrex cement was performed in all cases. The total-etch technique was used with: (1) 35% phosphoric acid; (2) OptiBond Solo Plus bonding agent; and (3) Filtek P60/shade B2 resin-based composite material. The restored teeth were sealed with Embrace pit and fissure sealant, monitored, and evaluated with periodic radiographs and clinical exams at 6-month recall visits. The results revealed that none of the 51 pulpotomized primary molars had evidence of periapical or furcation pathosis, recurrent decay, open margins, or broken restorations. In conclusion, this clinical study demonstrated that resin-based composite restorations--combined with the total-etch technique and a fifth-generation bonding agent and in direct contact with a fast-setting zinc oxide eugenol cement were long-lasting, quality clinical alternatives to restore the anatomy and function of pulpotomized primary molars. PMID:18477438

Caceda, Jorge H

2007-01-01

364

Histological evaluation of pulp tissue from second primary molars correlated with clinical and radiographic caries findings  

PubMed Central

Background: Managing dental caries in young children is demanding due to the elusions present on the right diagnostic criteria for treatment. The present study evaluated the histological status of pulp tissues extracted from primary second molar with caries involvement. Histological findings are correlated with clinical and radiographic assessment. Materials and Methods: Simple experimental study was conducted on upper or lower second primary molars with occlusal (22 teeth) or proximal (22 teeth) dental caries. Selected children were below 6 years of age. Percentage of caries involvement, residual dentin thickness (RDT), radiographic assessment of interradicular and periapical areas, clinical caries depth and signs and symptoms are the parameters considered for comparing with the histological findings. The specimens were grouped based on the nature of the inflammatory process as acute or chronic. The data were analyzed by Student t-test to compare histological types of inflammation with clinical parameters. P value < 0.05 was considered as significant. Results: Four cases revealed severe acute inflammation in coronal and relatively mild acute inflammation in radicular pulp. In the rest of the specimen coronal and radicular pulp had similar acute or chronic inflammatory changes. Histological evidence of pulpitis correlated with dental caries depth of ?80%, RDT of ?1 mm, radiographic rarefactions in the interradicular regions and symptoms of pain. Conclusion: Primary second molars with more than two-third caries involvement with symptoms of pain histologically showed inflammation of both coronal and radicular pulp tissues in all cases. PMID:24932190

Gopinath, Vellore Kannan; Anwar, Khurshid

2014-01-01

365

Prevalence of Three-Rooted Mandibular First Molars among Indians Using SCT  

PubMed Central

Undetected extra roots or root canals are a major reason for failure of endodontic treatment. Failure to recognize an extra distolingual (DL) root in mandibular first molar may lead to incomplete debridement of the root canal system and eventually treatment failure. Therefore, it is crucial that atypical anatomy is identified before and during dental treatment. Spiral computed tomography (SCT) images can show 3D images, and therefore much detail can be used when traditional methods prevent adequate endodontic treatment. The overall incidence of DL roots on the mandibular first molars was 6.40% for all patients and 5.00% for all teeth, respectively. The occurrence of DL roots on the right side and on the left side showed a statistically significant difference. The bilateral incidence of symmetrical distribution of DL roots was 56.25%. The DL root canal orifice was separated from DB canal orifice by 2.79 ± 0.34?mm, from the MB canal orifice by 4.23 ± 0.81?mm, and from the ML canal orifice by 3.29 ± 0.52?mm. The high prevalence of the DL root in permanent mandibular first molars among the Indian population by using SCT and estimations of the interorifice distance of such teeth might be useful for successful endodontic treatments. PMID:23840212

Garg, Amit Kumar; Tewari, Rajendra Kumar; Agrawal, Neha

2013-01-01

366

Gross enamel hypoplasia in molars from subadults in a 16th-18th century London graveyard.  

PubMed

Dental Enamel Hypoplasia has long been used as a common nonspecific stress indicator in teeth from archaeological samples. Most researchers report relatively minor linear and pitted hypoplastic defects on tooth crown surfaces. In this work we report a high prevalence and early age of onset of extensive enamel defects in deciduous and permanent molars in the subadults from the post-medieval cemetery of Broadgate, east central London. Analysis of the dentition of all 45 subadults from the cemetery, using both macroscopic and microscopic methods, reveals disturbed cusp patterns and pitted, abnormal and arrested enamel formation. Forty-one individuals from this group (93.2%) showed some evidence of enamel hypoplasia, 28 of them showing moderate or extensive lesions of molars, deciduous or permanent (63.6% of the sample). Scanning Electron Microscope images reveal many molars with grossly deformed cuspal architecture, multiple extra cusps and large areas of exposed Tomes' process pits, where the ameloblasts have abruptly ceased matrix production, well before normal completion. This indented, rough and poorly mineralized surface facilitates both bacterial adhesion and tooth wear, and when such teeth erupt fully into the mouth they are likely to wear and decay rapidly. We suggest that this complex combination of pitted and plane-form lesions, combined with disruption of cusp pattern and the formation of multiple small cusps, should henceforth be identified as "Cuspal Enamel Hypoplasia." PMID:17492667

Ogden, A R; Pinhasi, R; White, W J

2007-07-01

367

Fabrication and characterization of ZnO nanowire structure on flexible substrate with different solution molarities  

NASA Astrophysics Data System (ADS)

Zinc Oxide nanostructures are capable of applying numerous applications such as optoelectronics, sensors, varistors, and electronic devices. There are several techniques to gorw ZnO nanostructures, including vapor-liquid-solid method, chemical vapor deposition, physical vapor deposition, metal organic chemical vapor deposition and solution process. Recently reported solution method is a simple way to grow ZnO nanowires at a low temperature. One distinctive advantage with the solution method is low processing temperature so that flexible polymer materials can be used as a substrate to grow ZnO nanowires. In this study, ZnO nanowires have been fabricated on PET film by solution method with various molarities to see the effect of different molarities on ZnO nanowire growth. The solution temperature was 80°C and ZnO nanowires were grown for 6 hours for each case. The ZnO seed layer was sputtered at room temperature for 33 min. prior to ZnO nanowire growth. These ZnO nanowires were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and photoluminescence (PL) measurements at room temperature using a He-Cd 325-nm laser as the excitation source. We also measured the current using current Atomic Force Microscopy (I-AFM) and presented the possibility to use ZnO nanowires as a power source for micro/nano scale devices. As a result, we found that the characterization of ZnO nanowires changes according to the solution molarity.

Lee, Kyu-Hang; Hur, Shin; Kim, Wan-Doo; Choi, Hongsoo

2010-08-01

368

Effects of early unilateral mandibular first molar extraction on condylar and ramal vertical asymmetry  

PubMed Central

Objective: The objective of the following study is to investigate the mandibular vertical asymmetry in a group of patients with early unilateral mandibular first molar extractions. Materials and Methods: Mandibular asymmetry index measurements (condylar, ramal and condylar-plus-ramal) were performed on the panoramic radiographs of a study group including 51 patients (mean age: 18.60 ± 1.11 years) and a control group of 51 patients (mean age: 18.53 ± 1.29 years). Group I included patients with a unilateral mandibular first molar extracted before the age of 12 years. Group II included patients with no extractions and had excellent Class I relationships, no missing teeth and slight or moderate anterior crowding. A paired t-test was used to determine possible statistically significant differences between the sides for the measurements. Student's t-test was used for the comparison of asymmetry index values between the groups and genders. Results: No group showed statistically significant sex-or side-specific differences for posterior vertical height measurements. Condylar asymmetry index and ramal asymmetry index measurements were not statistically different between the groups, while condylar-plus-ramal asymmetry index (CRAI) measurements were statistically different between the groups (P = 0.019). Conclusions: A slight difference for CRAI value was found in patients with early unilateral mandibular first molar extractions. PMID:24966767

Halicioglu, Koray; Celikoglu, Mevlut; Buyuk, Suleyman K.; Sekerci, Ahmet E.; Candirli, Celal

2014-01-01

369

Partial confinement photonic crystal waveguides  

SciTech Connect

One-dimensional photonic crystal waveguides with an incomplete photonic band gap are modeled and proposed for an integration application that exploits their property of partial angular confinement. Planar apodized photonic crystal structures are deposited by plasma enhanced chemical vapor deposition and characterized by reflectivity as a function of angle and polarization, validating a partial confinement design for light at 850 nm wavelength. Partial confinement identifies an approach for tailoring waveguide properties by the exploitation of conformal film deposition over a substrate with angularly dependent topology. An application for an optoelectronic transceiver is demonstrated.

Saini, S.; Hong, C.-Y.; Pfaff, N.; Kimerling, L. C.; Michel, J. [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2008-12-29

370

Shape covariation between the craniofacial complex and first molars in humans.  

PubMed

The occurrence of mutual genetic loci in morphogenesis of the face and teeth implies shape covariation between these structures. However, teeth finalize their shape at an early age, whereas the face grows and is subjected to environmental influences for a prolonged period; it is therefore conceivable that covariation might modulate with age. Here we investigate the extent of this covariation in humans by measuring the 3D shape of the occlusal surface of the permanent first molars and the shape of the craniofacial complex from lateral radiographs, at two maturations stages. A sample of Greek subjects was divided into two groups (110 adult, 110 prepubertal) with equally distributed gender. The occlusal surfaces of the right first molars were 3D scanned from dental casts; 265 and 274 landmarks (including surface and curve semilandmarks) were digitized on the maxillary and mandibular molars, respectively. The corresponding lateral cephalometric radiographs were digitized with 71 landmarks. Geometric morphometric methods were used to assess shape variation and covariation. The vertical dimension of the craniofacial complex was the main parameter of shape variation, followed by anteroposterior deviations. The male craniofacial complex was larger (4.0-5.7%) and was characterized by a prominent chin and clockwise rotation of the cranial base (adult group only). Allometry was weak and statistically significant only when examined for the sample as a whole (percent variance explained: 2.1%, P = 0.0002). Covariation was statistically significant only between the lower first molar and the craniofacial complex (RV = 14.05%, P = 0.0099, and RV = 12.31%, P = 0.0162, for the prepubertal and adult groups, respectively). Subtle age-related covariation differences were noted, indicating that environmental factors may influence the pattern and strength of covariation. However, the main pattern was similar in both groups: a class III skeletal pattern (relative maxillary retrusion and mandibular protrusion), hyperdivergency, forward rotation of the posterior cranial base and upward rotation of the anterior cranial base were associated with mesiodistal elongation of the lower molars and height reduction of their distal cusps. This pattern mimics phylogeny in humans, where flexion and counterclockwise rotation of the cranial base, considered advantageous to survival, co-occur with tooth reductions that cannot be easily explained in evolutionary terms. The similarity of the phylogenetic and covariation patterns seems to support the pleiotropic gene hypothesis. PMID:24916927

Polychronis, Georgios; Halazonetis, Demetrios J

2014-08-01

371

Using Dalton's Law of Partial Pressures to Determine the Vapor Pressure of a Volatile Liquid  

ERIC Educational Resources Information Center

This experiment, designed for a general chemistry laboratory, illustrates the use of Dalton's law of partial pressures to determine the vapor pressure of a volatile liquid. A predetermined volume of air is injected into a calibrated tube filled with a liquid whose vapor pressure is to be measured. The volume of the liquid displaced is greater than…

Hilgeman, Fred R.; Bertrand, Gary; Wilson, Brent

2007-01-01

372

Epidemiological study of complete and partial hydatidiform mole in Abu Dhabi: influence age and ethnic group.  

PubMed Central

An unmatched case control study of molar pregnancy was carried out at this hospital between 1978 and 1987 to investigate the influence of maternal age and ethnic group on the incidence of complete and partial hydatidiform mole. The age specific incidence of complete mole was minimal between the ages of 30 and 34 years (relative risk 1), showed a minor peak in teenagers (relative risk 3.1, 95% confidence interval 6.5-1.4), and a major peak in those of 35 years and over. Between 35 and 39 years the relative risk was 2.5 (95% CI 6.2-1.0) and at 40 years or more the relative risk was 9.8 (95% CI 28.9-3.3). No age group showed a significantly increased risk of partial mole. The women of Abu Dhabi had increased risks of both forms of molar pregnancy relative to women in Nottingham, England (relative risk 1): the risk of complete mole was increased threefold (95% CI 4.2-2.2) and that of partial mole twofold (95% CI 4.0-1.2). The increased risk of complete mole was greatest in Gulf Arabs (mainly Omanis and Yemenis) who had a sixfold increase in crude relative risk (95% CI 10.7-3.5). The increased risks of complete mole associated with maternal ethnic group remained after adjustment for maternal age distribution. PMID:2401735

Graham, I H; Fajardo, A M; Richards, R L

1990-01-01

373

Spiral Computed Tomographic Evaluation and Endodontic Management of a Mandibular Second Molar with Four Roots. A Case Report and Literature Review  

PubMed Central

The vast majority of mandibular second molars have two roots with three root canals; however, variations in molar root canal anatomy are not uncommon. To the best of our knowledge, four rooted mandibular second molar with three mesial roots and one distal root has never been reported. Herein, we present the endodontic management of a four rooted mandibular second molar tooth, diagnosed with the assistance of spiral computed tomography (SCT) with a brief review of literature. PMID:23717333

Purra, Aamir Rashid; Mushtaq, Mubashir; Robbani, Irfan; Farooq, Riyaz

2013-01-01

374

Thymectomy through lateralized partial sternotomy  

PubMed Central

A young woman with nonthymomic myasthenia gravis with failure of medical treatment was offered thymectomy through partial sternotomy. Shifting of vertical arm of “L” incision laterally avoids fracture of opposite sternal flange and provides better sternal stability postoperatively. PMID:22022149

Mohite, Prashant N.; Rana, Sandip Singh; Sadasivan, Prasanth; Deshpande, Swapnil

2011-01-01

375

Partial belief and expert testimony  

E-print Network

My dissertation investigates two questions from within a partial belief framework: First, when and how should deference to experts or other information sources be qualified? Second, how closely is epistemology related to ...

Briggs, Rachael (Rachael Amy)

2009-01-01

376

Scrolling partially ordered event displays  

Microsoft Academic Search

Understanding the partial-order relationship between events is critical to understand the behaviour of a distributed or parallel application. Many problems need to be solved in order to provide an accurate and useful display of a large partial order, such as will occur during the execution of any non-trivial application. A display will most likely resemble a process-time diagram, but the

David Taylor

2005-01-01

377

Partially sparse imaging of stationary indoor scenes  

NASA Astrophysics Data System (ADS)

In this paper, we exploit the notion of partial sparsity for scene reconstruction associated with through-the-wall radar imaging of stationary targets under reduced data volume. Partial sparsity implies that the scene being imaged consists of a sparse part and a dense part, with the support of the latter assumed to be known. For the problem at hand, sparsity is represented by a few stationary indoor targets, whereas the high scene density is defined by exterior and interior walls. Prior knowledge of wall positions and extent may be available either through building blueprints or from prior surveillance operations. The contributions of the exterior and interior walls are removed from the data through the use of projection matrices, which are determined from wall- and corner-specific dictionaries. The projected data, with enhanced sparsity, is then processed using l 1 norm reconstruction techniques. Numerical electromagnetic data is used to demonstrate the effectiveness of the proposed approach for imaging stationary indoor scenes using a reduced set of measurements.

Ahmad, Fauzia; Amin, Moeness G.; Dogaru, Traian

2014-12-01

378

Studies on the phase diagram of Pb-Fe-O system and standard molar Gibbs energy of formation of 'PbFe5O8.5' and Pb2Fe2O5  

NASA Astrophysics Data System (ADS)

Partial phase diagram of Pb-Fe-O system has been established by phase equilibration studies over a wide temperature range coupled with high temperature solid electrolyte based emf cells. Ternary oxides are found to coexist with liquid lead only at temperatures above 900 K. At temperatures below 900 K, iron oxides coexist with liquid lead. Standard molar Gibbs energy of formation of ternary oxides 'PbFe5O8.5' and Pb2Fe2O5 were determined by measuring equilibrium oxygen partial pressures over relevant phase fields using emf cells and are given by the following expressions: ?fGmo 'PbFeO'±1.0(kJ mol)=-2208.1+0.6677(T/K) (917?T/K?1117) ?fGmo PbFeO±0.8(kJ mol)=-1178.4+0.3724(T/K) (1050?T/K?1131) .

Sahu, Sulata Kumari; Ganesan, Rajesh; Gnanasekaran, T.

2012-07-01

379

Endodontic management of maxillary first molar with seven root canals diagnosed using Cone Beam Computed Tomography scanning  

PubMed Central

The main objective of root canal treatment is thorough cleaning and shaping of the entire pulp space and its complete filling with an inert filling material. A major cause of post-treatment disease is the inability to locate, debride or adequately fill all canals of the root canal system. The form, configuration, and number of root canals in the maxillary first molars have been discussed for more than half a century. Maxillary first molars commonly present with three roots and three canals, with a second mesiobuccal canal (MB2) also present. With the advent of improved magnification there are reports of multiple root canals in the maxillary first molars. Nonsurgical endodontic therapy of a left maxillary first molar with three roots and seven root canals was successfully performed under a dental operating microscope. The diagnosis of multiple root canals was confirmed with the help of Cone Beam Computed Tomography (CBCT) images.

Raghavendra, Srinidhi Surya; Hindlekar, Ajit Narayan; Desai, Niranjan Nanasaheb; Vyavahare, Nishant Kishor; Napte, Bandu Devrao

2014-01-01

380

Implantation of an RFID-tag into human molars to reduce hard forensic identification labor. Part 2: Physical properties  

Microsoft Academic Search

Modifying and implanting existing RFID-tags into extracted human molars was described previously [P. Thevissen, G. Poelman, B. Puers, M. De Cooman, G. Willems, Implantation of RFID-tag into human molars to reduce hard forensic identification labor. Part 1. Working principle, Forensic Sci. Int. 156 (2006)]. Maximal vertical occlusal load during which the implanted RFID-tags remain active was evaluated in vitro. The

Patrick W. Thevissen; Guy Poelman; Michel De Cooman; Robert Puers; Guy Willems

2006-01-01

381

Considerations of mandibular angle fractures during and after surgery for removal of third molars: a review of the literature  

Microsoft Academic Search

Background  Angle fractures are quite common considering that the angle of the mandible forms an area of lower resistance which contains\\u000a a thicker upper border, a thin basilar bone, and the presence of an impacted mandibular third molar. Common complications\\u000a of mandibular third molar surgery include alveolar osteitis (dry socket), secondary infection, nerve dysfunction, and hemorrhage.\\u000a Reports of mandibular fracture during

Bruno Ramos Chrcanovic; Antônio Luís Neto Custódio

2010-01-01

382

Partial melting in pelitic rock under shear deformation  

Microsoft Academic Search

We describe the mechanism of strain localization, coupled with the process of melt segregation in partially molten metapelitic rocks. Torsion experiments were performed on very fine grained aggregates of muscovite and quartz (respectively 0.3 and 0.7 by volume) at T = 750° C, P = 300 MPa, and a constant shear strain rate of 3x10-4 s-1 for finite shear strains

S. Misra; L. Burlini

2009-01-01

383

Characteristics of bony changes and tooth displacement in the mandibular cystic lesion involving the impacted third molar  

PubMed Central

Objectives The purpose of this retrospective study is to find the differentiating characteristics of cystic and cystic-appearing lesions that involve the impacted mandibular third molar by analyzing panoramic radiographs and computed tomography images, and to aid the preoperative diagnosis. Materials and Methods Eighty-one patients who had a mandibular cystic or cystic-appearing lesion that involved impacted mandibular third molar and underwent cyst enucleation were included in the study. The preoperative panoramic radiograph and computed tomography findings were analyzed in accordance to the histopathologic type. Results Most of the cystic lesions containing the mandibular third molar were diagnosed as a dentigerous cyst (77.8%). The occurrence of mesio-distal displacement of the third molar was more frequent in the odontogenic keratocyst (71.4%) and in the ameloblastoma (85.7%) than in the dentigerous cyst (19.1%). Downward displacement was primarily observed in each group. Odontogenic keratocyst and ameloblastoma showed more aggressive growth pattern with higher rate of bony discontinuity and cortical bone expansion than in dentigerous cyst. Conclusion When evaluating mandibular cystic lesions involving the impacted mandibular third molar, dentigerous cyst should first be suspected. However, when the third molar displacement and cortical bone absorption are observed, then odontogenic keratocyst or ameloblastoma should be considered. PMID:25368835

Lee, Jin-Hyeok; Kim, Sung-Min; Kim, Hak-Jin; Jeon, Kug-Jin; Park, Kwang-Ho

2014-01-01

384

Comparative studies between mice molars and incisors are required to draw an overview of enamel structural complexity  

PubMed Central

In the field of dentistry, the murine incisor has long been considered as an outstanding model to study amelogenesis. However, it clearly appears that enamel from wild type mouse incisors and molars presents several structural differences. In incisor, exclusively radial enamel is observed. In molars, enamel displays a high level of complexity since the inner part is lamellar whereas the outer enamel shows radial and tangential structures. Recently, the serotonin 2B receptor (5-HT2BR) was shown to be involved in ameloblast function and enamel mineralization. The incisors from 5HT2BR knockout (KO) mice exhibit mineralization defects mostly in the outer maturation zone and porous matrix network in the inner zone. In the molars, the mutation affects both secretory and maturation stages of amelogenesis since pronounced alterations concern overall enamel structures. Molars from 5HT2BR KO mice display reduction in enamel thickness, alterations of inner enamel architecture including defects in Hunter-Schreger Bands arrangements, and altered maturation of the outer radial enamel. Differences of enamel structure were also observed between incisor and molar from other KO mice depleted for genes encoding enamel extracellular matrix proteins. Thus, upon mutation, enamel analysis based exclusively on incisor defects would be biased. In view of the functional relationship between enamel structure and tooth morphogenesis, identification of molecular actors involved in amelogenesis requires comparative studies between mice molars and incisors. PMID:25285079

Goldberg, Michel; Kellermann, O.; Dimitrova-Nakov, S.; Harichane, Y.; Baudry, A.

2014-01-01

385

Unique inhibitory cascade pattern of molars in canids contributing to their potential to evolutionary plasticity of diet  

PubMed Central

Developmental origins that guide the evolution of dental morphology and dental formulae are fundamental subjects in mammalian evolution. In a previous study, a developmental model termed the inhibitory cascade model was established. This model could explain variations in relative molar sizes and loss of the lower third molars, which sometimes reflect diet, in murine rodents and other mammals. Here, I investigated the pattern of relative molar sizes (inhibitory cascade pattern) in canids, a taxon exhibiting a wide range of dietary habits. I found that interspecific variation in canid molars suggests a unique inhibitory cascade pattern that differs from that in murine rodents and other previously reported mammals, and that this variation reflects dietary habits. This unique variability in molars was also observed in individual variation in canid species. According to these observations, canid species have greater variability in the relative sizes of first molars (carnassials), which are functionally important for dietary adaptation in the Carnivora. In conclusion, an inhibitory cascade that differs from that in murine rodents and other mammals may have contributed to diverse dietary patterns and to their parallel evolution in canids. PMID:23467478

Asahara, Masakazu

2013-01-01

386

Report on ISS Oxygen Production, Resupply, and Partial Pressure Management  

NASA Technical Reports Server (NTRS)

The majority of oxygen used on International Space Station (ISS) is for metabolic support and denitrogenation procedures prior to Extra-Vehicular Activities. Oxygen is supplied by various visiting vehicles such as the Progress and Shuttle in addition to oxygen production capability on both the United States On-Orbit Segment (USOS) and Russian Segment (RS). To maintain a habitable atmosphere the oxygen partial pressure is controlled between upper and lower bounds. The full range of the allowable oxygen partial pressure along with the increased ISS cabin volume is utilized as a buffer allowing days to pass between oxygen production or direct addition of oxygen to the atmosphere from reserves. This paper summarizes amount of oxygen supplied and produced from all of the sources and describes past experience of managing oxygen partial pressure along with the range of management options available to the ISS.

Schaezler, Ryan; Ghariani, Ahmed; Leonard, Daniel; Lehman, Daniel

2011-01-01

387

Influence of Different Apical Preparations on Root Canal Cleanliness in Human Molars: a SEM Study  

PubMed Central

ABSTRACT Objectives To compare the influence of type and dimensions of the apical preparation on the cleanliness of the apical area in molars. Material and Methods A total of 120 root canals (MB and DB root canals from 30 maxillary molars and mesial root canals from 30 mandibular molars) were instrumented with Mtwo NiTi rotary instruments to a size 25/0.06 taper and were equally divided into three different experimental groups depending on the subsequently apical root canal preparation: Group 1: no further apical preparation, Group 2: apical preparation with Mtwo files to a size 40/0.04 taper, Group 3: apical preparation with Mtwo Apical Files. All root canals were observed through scanning electron microscopy (SEM). Presence of superficial debris and smear layer was evaluated using a score system. Data were statistically analysed using the Kruskal-Wallis and Bonferroni tests with a level of significance set at P < 0.05. Results Kruskal-Wallis test revealed no differences among groups in the middle and coronal third (P > 0.05), while at the apical level, there was a significant difference for both residual debris and presence of smear layer between Group 1 and both Group 2 (P = 0.003 and P = 0.014) and 3 (P = 0.012 and P = 0.021), while no difference was present between Group 2 and Group 3 (P = 0.871 and P = 0.923). Conclusions Cleanliness of the apical third in terms of debris and smear layer was statistically better when an apical preparation was performed to a size 40/0.04 taper or with the use of the Mtwo Apical Files. PMID:25089176

Grande, Nicola M.; Tocci, Luigi; Testarelli, Luca; Gambarini, Gianluca

2014-01-01

388

Function of pretribosphenic and tribosphenic mammalian molars inferred from 3D animation.  

PubMed

Appearance of the tribosphenic molar in the Late Jurassic (160 Ma) is a crucial innovation for food processing in mammalian evolution. This molar type is characterized by a protocone, a talonid basin and a two-phased chewing cycle, all of which are apomorphic. In this functional study on the teeth of Late Jurassic Dryolestes leiriensis and the living marsupial Monodelphis domestica, we demonstrate that pretribosphenic and tribosphenic molars show fundamental differences of food reduction strategies, representing a shift in dental function during the transition of tribosphenic mammals. By using the Occlusal Fingerprint Analyser (OFA), we simulated the chewing motions of the pretribosphenic Dryolestes that represents an evolutionary precursor condition to such tribosphenic mammals as Monodelphis. Animation of chewing path and detection of collisional contacts between virtual models of teeth suggests that Dryolestes differs from the classical two-phased chewing movement of tribosphenidans, due to the narrowing of the interdental space in cervical (crown-root transition) direction, the inclination angle of the hypoflexid groove, and the unicuspid talonid. The pretribosphenic chewing cycle is equivalent to phase I of the tribosphenic chewing cycle, but the former lacks phase II of the tribosphenic chewing. The new approach can analyze the chewing cycle of the jaw by using polygonal 3D models of tooth surfaces, in a way that is complementary to the electromyography and strain gauge studies of muscle function of living animals. The technique allows alignment and scaling of isolated fossil teeth and utilizes the wear facet orientation and striation of the teeth to reconstruct the chewing path of extinct mammals. PMID:25091547

Schultz, Julia A; Martin, Thomas

2014-10-01

389

Effect of submucosal and intramuscular dexamethasone on postoperative sequelae after third molar surgery: comparative study.  

PubMed

We compared the effects of dexamethasone sodium phosphate given submucosally and intramuscularly on postoperative complications after removal of impacted lower third molars in a preliminary randomised prospective clinical trial. Thirty patients, each of whom required removal of a single impacted mandibular third molar under local anaesthesia, were randomly allocated to one of 3 groups of 10 each. The 2 experimental groups were given dexamethasone 4 mg submucosally or intramuscularly, and the control group had no steroid. Facial swelling and maximal interincisal distance were measured by an independent examiner at baseline (preoperatively), and at 1, 3, and 7 days postoperatively. Pain was measured by counting the number of rescue analgesic tablets taken, and from the patients' response to a visual analogue scale (VAS). The mean age of the 16 men and 14 women was 27 years (range 20-48). Both dexamethasone groups showed significant reductions in swelling (p<0.001) and in pain (p<0.05) compared with the control group at all intervals. Submucosal dexamethasone resulted in significantly less trismus than controls on day 1 postoperatively (p=0.04), but there were no significant differences among the groups at the other times. The effects of the two routes of dexamethasone were comparable for all variables. There were no cases of alveolar osteitis or wound infection. Dexamethasone 4 mg given submucosally is an effective way of minimising swelling, trismus, and pain after removal of impacted lower third molars, and is comparable with the intramuscular route. It offers a simple, safe, painless, non-invasive, and cost-effective treatment in moderate and severe cases. PMID:21035237

Majid, Omer Waleed; Mahmood, Waseem Khalid

2011-12-01

390

Mineral Trioxide Aggregate vs. Calcium Hydroxide in Primary Molar Pulpotomy: A Systematic Review  

PubMed Central

Introduction: The aim of this quantitative systematic review/meta-analysis was to compare the treatment outcomes of mineral trioxide aggregate (MTA) and calcium hydroxide (CH) in pulpotomy of human primary molars. The focused PICO question was “in case of pulp exposure in vital primary molars, how does MTA pulpotomy compare to CH in terms of clinical/radiographic success?” Methods and Materials: We retrieved published randomized clinical trials (RCTs) of at least 6-month duration; our search included articles published up to March 2013 in five following databases: PubMed (Medline), Cochrane database of systematic reviews, Science Citation Index, EMBASE, and Google Scholar. Mantel Haenszel and Inverse Variance-weighted methods were applied by STATA; the relative risk (RR) was calculated with 95% confidence intervals (CI). Results: A total of 282 English articles were collected. Two authors independently screened the articles and five RCTs were selected; data extraction and quality assessment were then carried out. Four RCTs were appropriate for meta-analysis according to their follow-up times by Mantel Haenszel method. Statistically significant difference was found between success rate of MTA compared to CH, with RR=0.08 (95% CI, 0.02-0.39), RR=0.19 (95% CI, 0.08-0.46), and RR=0.38 (95% CI, 0.21-0.68) for 6-, 12-, and 24-month follow-ups, respectively. A significant difference was also observed for all included RCTs after analyses using the Inverse Variance-weighted method (RR=0.44; 95% CI, 0.27-0.72). Conclusions: Systematic review/meta-analysis of included RCTs revealed that for pulpotomy of vital primary molars, MTA has better treatment outcomes compared to CH. PMID:24688575

Shirvani, Armin; Hassanizadeh, Raheleh; Asgary, Saeed

2014-01-01

391

Construction of a cDNA library for miniature pig mandibular deciduous molars  

PubMed Central

Background The miniature pig provides an excellent experimental model for tooth morphogenesis because its diphyodont and heterodont dentition resembles that of humans. However, little information is available on the process of tooth development or the exact molecular mechanisms controlling tooth development in miniature pigs or humans. Thus, the analysis of gene expression related to each stage of tooth development is very important. Results In our study, after serial sections were made, the development of the crown of the miniature pigs’ mandibular deciduous molar could be divided into five main phases: dental lamina stage (E33-E35), bud stage (E35-E40), cap stage (E40-E50), early bell stage (E50-E60), and late bell stage (E60-E65). Total RNA was isolated from the tooth germ of miniature pig embryos at E35, E45, E50, and E60, and a cDNA library was constructed. Then, we identified cDNA sequences on a large scale screen for cDNA profiles in the developing mandibular deciduous molars (E35, E45, E50, and E60) of miniature pigs using Illumina Solexa deep sequencing. Microarray assay was used to detect the expression of genes. Lastly, through Unigene sequence analysis and cDNA expression pattern analysis at E45 and E60, we found that 12 up-regulated and 15 down-regulated genes during the four periods are highly conserved genes homologous with known Homo sapiens genes. Furthermore, there were 6 down-regulated and 2 up-regulated genes in the miniature pig that were highly homologous to Homo sapiens genes compared with those in the mouse. Conclusion Our results not only identify the specific transcriptome and cDNA profile in developing mandibular deciduous molars of the miniature pig, but also provide useful information for investigating the molecular mechanism of tooth development in the miniature pig. PMID:24750690

2014-01-01

392

Absolute silicon molar mass measurements, the Avogadro constant and the redefinition of the kilogram  

NASA Astrophysics Data System (ADS)

The results of an absolute silicon molar mass determination of two independent sets of samples from the highly 28Si-enriched crystal (AVO28) produced by the International Avogadro Coordination are presented and compared with results published by the Physikalisch-Technische Bundesanstalt (PTB, Germany), the National Research Council (NRC, Canada) and the National Metrology Institute of Japan (NMIJ, Japan). This study developed and describes significant changes to the published protocols for producing absolute silicon isotope ratios. The measurements were made at very high resolution on a multi-collector inductively coupled plasma mass spectrometer using tetramethylammonium hydroxide (TMAH) to dissolve and dilute all samples. The various changes in the measurement protocol and the use of TMAH resulted in significant improvements to the silicon isotope ratio precision over previously reported measurements and in particular, the robustness of the 29Si/30Si ratio of the AVO28 material. These new results suggest that a limited isotopic variability is present in the AVO28 material. The presence of this variability is at present singular and therefore its significance is not well understood. Fortunately, its magnitude is small enough so as to have an insignificant effect on the overall uncertainty of an Avogadro constant derived from the average molar mass of all four AVO28 silicon samples measured in this study. The NIST results confirm the AVO28 molar mass values reported by PTB and NMIJ and confirm that the virtual element-isotope dilution mass spectrometry approach to calibrated absolute isotope ratio measurements developed by PTB is capable of very high precision as well as accuracy. The Avogadro constant NA and derived Planck constant h based on these measurements, together with their associated standard uncertainties, are 6.02214076(19) × 1023 mol-1 and 6.62607017(21) × 10-34 Js, respectively.

Vocke, R. D., Jr.; Rabb, S. A.; Turk, G. C.

2014-10-01

393

Function of pretribosphenic and tribosphenic mammalian molars inferred from 3D animation  

NASA Astrophysics Data System (ADS)

Appearance of the tribosphenic molar in the Late Jurassic (160 Ma) is a crucial innovation for food processing in mammalian evolution. This molar type is characterized by a protocone, a talonid basin and a two-phased chewing cycle, all of which are apomorphic. In this functional study on the teeth of Late Jurassic Dryolestes leiriensis and the living marsupial Monodelphis domestica, we demonstrate that pretribosphenic and tribosphenic molars show fundamental differences of food reduction strategies, representing a shift in dental function during the transition of tribosphenic mammals. By using the Occlusal Fingerprint Analyser (OFA), we simulated the chewing motions of the pretribosphenic Dryolestes that represents an evolutionary precursor condition to such tribosphenic mammals as Monodelphis. Animation of chewing path and detection of collisional contacts between virtual models of teeth suggests that Dryolestes differs from the classical two-phased chewing movement of tribosphenidans, due to the narrowing of the interdental space in cervical (crown-root transition) direction, the inclination angle of the hypoflexid groove, and the unicuspid talonid. The pretribosphenic chewing cycle is equivalent to phase I of the tribosphenic chewing cycle, but the former lacks phase II of the tribosphenic chewing. The new approach can analyze the chewing cycle of the jaw by using polygonal 3D models of tooth surfaces, in a way that is complementary to the electromyography and strain gauge studies of muscle function of living animals. The technique allows alignment and scaling of isolated fossil teeth and utilizes the wear facet orientation and striation of the teeth to reconstruct the chewing path of extinct mammals.

Schultz, Julia A.; Martin, Thomas

2014-10-01

394

A computerised third molar surgery simulator--results of supervision by different professionals.  

PubMed

The purpose of the study was to investigate which supervisory approach afforded the most efficient learning method for undergraduate students in oral and maxillofacial surgery (OMS) using a computerised third molar surgery simulator. Fifth year dental students participated voluntarily in a randomised experimental study using the simulator. The amount of time required and the number of trials used by each student were evaluated as a measure of skills development. Students had the opportunity to practise the procedure until no further visible improvements were achieved. The study assessed four different types of supervision to guide the students. The first group was where they were supported by a teacher/specialist in OMS, the second by a teaching assistant, the third group practised without any supervision and the fourth received help from a simulator technician/engineer. A protocol describing assessment criteria was designed for this purpose, and a questionnaire was completed by all participating students after the study. The average number of attempts required to virtually remove a third molar tooth in the simulator was 1.44 times for the group supervised by an OMS teacher; 1.5 times for those supervised by a teaching assistant; 2.8 times for those who had no supervision; and 3.6 times when support was provided only by a simulator technician. The results showed that the most efficient experience of the students was when they were helped by an OMS teacher or a teaching assistant. In a time and cost-effective perspective, supervision by a teaching assistant for a third molar surgery simulator would be the optimal choice. PMID:24521173

Rosen, A; Eliassi, S; Fors, U; Sallnäs, E-L; Forsslund, J; Sejersen, R; Lund, B

2014-05-01

395

Partial Recovery of Quantum Entanglement  

E-print Network

Suppose Alice and Bob try to transform an entangled state shared between them into another one by local operations and classical communications. Then in general a certain amount of entanglement contained in the initial state will decrease in the process of transformation. However, an interesting phenomenon called partial entanglement recovery shows that it is possible to recover some amount of entanglement by adding another entangled state and transforming the two entangled states collectively. In this paper we are mainly concerned with the feasibility of partial entanglement recovery. The basic problem we address is whether a given state is useful in recovering entanglement lost in a specified transformation. In the case where the source and target states of the original transformation satisfy the strict majorization relation, a necessary and sufficient condition for partial entanglement recovery is obtained. For the general case we give two sufficient conditions. We also give an efficient algorithm for the feasibility of partial entanglement recovery in polynomial time. As applications, we establish some interesting connections between partial entanglement recovery and the generation of maximally entangled states, quantum catalysis, mutual catalysis, and multiple-copy entanglement transformation.

Runyao Duan; Yuan Feng; Mingsheng Ying

2004-04-07

396

Radicular cyst followed by incomplete pulp therapy in primary molar: a case report.  

PubMed

Radicular cysts are one of the most common odontogenic cyst of the jaws. However, those arising from primary teeth are rare. An 8-year-old boy reported to the Department of Pedodontics and Preventive Dentistry with the chief complaint of pain and swelling on the lower left primary molar tooth region. Radiographic examination revealed a well-defined radiolucency with continuous hyperostotic border. Considering the age of the child, size of lesion, and involvement of unerupted premolars; marsupialization was preferred as a conservative treatment of choice. The success of the treatment was evident both clinically and radiographically during the follow-up period. PMID:24021332

Nagarathna, C; Jaya, A R; Jaiganesh, I

2013-01-01

397

Analysis of the internal anatomy of maxillary first molars by using different methods.  

PubMed

The success of endodontic treatment depends on the identification of all root canals so that they can be cleaned, shaped, and obturated. This study investigated internal morphology of maxillary first molars by 3 different methods: ex vivo, clinical, and cone beam computed tomography (CBCT) analysis. In all these different methods, the number of additional root canals and their locations, the number of foramina, and the frequency of canals that could or could not be negotiated were recorded. In the ex vivo study, 140 extracted maxillary first molars were evaluated. After canals were accessed and detected by using an operating microscope, the teeth with significant anatomic variances were cleared. In the clinical analysis, the records of 291 patients who had undergone endodontic treatment in a dental school during a 2-year period were used. In the CBCT analysis, 54 maxillary first molars were evaluated. The ex vivo assessment results showed a fourth canal frequency in 67.14% of the teeth, besides a tooth with 7 root canals (0.72%). Additional root canals were located in the mesiobuccal root in 92.85% of the teeth (17.35% could not be negotiated), and when they were present, 65.30% exhibited 1 foramen. Clinical assessment showed that 53.26%, 0.35%, and 0.35% of the teeth exhibited 4, 5, and 6 root canals, respectively. Additional root canals were located in this assessment in mesiobuccal root in 95.63% (27.50% could not be negotiated), and when they were present, 59.38% exhibited 1 foramen. CBCT results showed 2, 4, and 5 root canals in 1.85%, 37.05%, and 1.85% of the teeth, respectively. When present, additional canals showed 1 foramen in 90.90% of the teeth studied. This study demonstrated that operating microscope and CBCT have been important for locating and identifying root canals, and CBCT can be used as a good method for initial identification of maxillary first molar internal morphology. PMID:19249591

Baratto Filho, Flares; Zaitter, Suellen; Haragushiku, Gisele Aihara; de Campos, Edson Alves; Abuabara, Allan; Correr, Gisele Maria

2009-03-01

398

[Preparation and properties of prostaglandin D2 labelled with tritium with high molar radioactivity].  

PubMed

Kinetic parameters of enzymatic and non-enzymatic transformations of [3H]prostaglandin H2 (PGH2) were determined; the maximum yield of [3H]PGD2 being obtained at the keobs/koobs ratio equal to 10. The two-stage enzymatic synthesis of [3H]PGD2 with high molar radioactivity (3.15 TBq/mmol) from [3H]arachidonic acid carried out. Its identity in properties to the natural PGD2 was shown in experiments on the inhibition of ADP-induced aggregation of thrombocytes and on enzymatic oxidation with 15-hydroxyprostaglandin dehydrogenase. PMID:2590255

Shram, S I; Vrzheshch, P V; Bobrovich, O A; Tatarintsev, A V; Shevchenko, V P; Miasoedov, N F

1989-09-01

399

Dentigerous cyst associated with ectopic maxillary third molar in maxillary antrum  

PubMed Central

The treatment of ectopic maxillary tooth is surgical removal via a Caldwell-Luc procedure. Trans-nasal extraction of tooth may be attempted if the tooth is small and sited near the maxillary antrum. It is also mandatory to completely remove all pathological antral tissue and thoroughly assess all resected soft tissue histologically. This is important as certain antral pathologies such as dentigerous cyst, as in this case, may co-exist with an ectopic molar. It is thus important to follow-up such patients. In the absence of any unusual histology, surgery provides the patient with a definitive cure of his symptoms. PMID:22696724

Thakur, Gagan; Nair, Preeti P; Thomas, Shaji; Ahuja, Ruchi; Kothari, Rohit

2011-01-01

400

Treatment of dentoskeletal bimaxillary protrusion: additional extraction of maxillary second molars.  

PubMed

This case report describes the orthodontic treatment of an 18-year-old female patient with Class II malocclusion with dentoskeletal bimaxillary protrusion. An acceptable treatment result was obtained with a four first premolar extraction and an additional maxillary two second molar extraction plan. Standard edgewise appliances were placed after the premolars were extracted. A positive soft tissue response to treatment was achieved, and the patient's profile was improved, with a reduction of lip protrusion and mentalis strain. Dentally, the interincisal angle improved significantly as both the maxillary and mandibular incisors were uprighted after space closure. The occlusion remained stable during 2 years of follow-up. PMID:19639455

Iijima, Shigeki; Yoshida, Mitsuru; Terada, Kazuto

2009-07-01

401

Molar microwear in Praeanthropus afarensis: evidence for dietary stasis through time and under diverse paleoecological conditions.  

PubMed

Molar microwear fabrics in extant mammals vary with diet and, more particularly, the physical properties of the items that are consumed. Praeanthropus afarensis is well represented in the fossil record over a prolonged and radiometrically controlled temporal span, and reasonably robust paleoecological reconstructions are available for the various localities from which it is known. We therefore examined molar microwear in this species to determine whether diet varied in relation to time or in response to different ecological conditions. Of more than 70 specimens of Pr. afarensis that contain one or more worn permanent molars, only 19 were found to be suitable for microwear analysis. These derive from eight temporal horizons in the Laetolil Beds and Hadar Formation spanning approximately 400kyr (3.6-3.2Ma). Six paleoecological categories have been reconstructed for these horizons, and these were ranked on the basis of floral cover. None of the microwear variables observed for Pr. afarensis is significantly associated with either temporal or paleoecological rank. Thus, microwear and, by extension, diet does not appear to have altered significantly in Pr. afarensis through time or in response to different paleoecological circumstances. The wear pattern that appears to have characterized Pr. afarensis overlaps extensively that of Gorilla gorilla beringei and differs notably from the fabrics of extant primates (e.g., Cebus apella and Cercocebus albigena) that consume hard objects. The high proportion of scratches on Pr. afarensis molars suggests the inclusion of fine abrasives in or on the food items consumed by those individuals sampled in this study. Although Pr. afarensis may have been morphologically equipped to process hard, brittle items, the microwear data suggest that it did not necessarily do so, even in the face of varying environmental circumstances. Explanatory scenarios that describe Pr. afarensis as part of an evolutionary trajectory involving a more heavily masticated diet with an increased reliance on hard, brittle items need to be reconsidered. However, fallback foods that were consumed during relatively short, albeit critical periods may have exerted sufficient selective pressure to explain the evolution of the comparatively robust Pr. afarensis trophic apparatus. Because it is unlikely that many individuals from such restricted temporal intervals would be sampled in the paleontological record, we suggest that the most productive approach to the elucidation of paleodiet is the integration of genetic (morphological) and epigenetic (microwear and isotopic) lines of evidence. PMID:16750841

Grine, Frederick E; Ungar, Peter S; Teaford, Mark F; El-Zaatari, Sireen

2006-09-01

402

Coronectomy of a lower third molar in combination with vital pulp therapy  

PubMed Central

Coronectomy is a procedure that intentionally spares the vital root after removal of the crown of the lower third molar to avoid damage to the inferior alveolar nerve. Vital pulp therapy is one option for managing exposed pulp tissue to reduce the risk of pulpal inflammation or necrosis. Among various dental materials, mineral trioxide aggregate (MTA) has been successfully used for vital pulp therapy. Thus, this case report discusses a coronectomy procedure in combination with vital pulp therapy using MTA. This case also attempts to highlight the formation of tertiary dentin, evidence of successful vital pulp therapy. PMID:25202226

Kim, Young-Bin; Joo, Woo-Hee; Min, Kyung-San

2014-01-01

403

Designing successful removable partial dentures.  

PubMed

In today's busy dental offices, removable partial denture design is often abdicated by dentists, both as a result of a lack of experience and consensus of design and because of educational failure on the part of dental schools. The result is delegation of the clinical design process to the lab technician. The lack of clinical data provided to the dental technician jeopardizes the quality of care. This article will focus on a logical and simple approach to this problem, making removable partial denture design simple and predictably achievable. The clinical evidence related to removable partial denture design will be described, along with a checklist to simplify the process and make it practical and applicable to everyday clinical practice. PMID:16553007

Daher, Tony; Hall, Dan; Goodacre, Charles J

2006-03-01

404

Partial decoherence in mesoscopic systems  

NASA Astrophysics Data System (ADS)

The coupling of a mesoscopic system with its environment usually causes total decoherence: at long times the reduced density matrix of the system evolves in time to a limit that is independent of its initial value, losing all the quantum information stored in its initial state. Under special circumstances, a subspace of the system's Hilbert space remains coherent or ‘decoherence-free’, and the reduced density matrix approaches a non-trivial limit that contains information on its initial quantum state, despite the coupling with the environment. This situation is called ‘partial decoherence’. In this paper, we found the conditions for partial decoherence in a mesoscopic system (with N quantum states) that is coupled to its environment. When the Hamiltonian of the system commutes with the total Hamiltonian, one has ‘adiabatic decoherence’, which yields N - 1 time-independent combinations of the reduced density matrix elements. In the presence of a magnetic flux, one can measure circulating currents around loops in the system even at long times and use them to retrieve information on the initial state. For N = 2, we demonstrate that partial decoherence can happen only under adiabatic decoherence conditions. However, for N > 2 we find partial decoherence even when the Hamiltonian of the system does not commute with the total Hamiltonian, and we obtain the general conditions for such a non-adiabatic partial decoherence. For an electron moving on a ring, with N > 2 single-level quantum dots, non-adiabatic partial decoherence can arise only when the total flux through the ring vanishes (or equals an integer number of flux quanta), and therefore there is no asymptotic circulating current.

Aharony, Amnon; Gurvitz, Shmuel; Tokura, Yasuhiro; Entin-Wohlman, Ora; Dattagupta, Sushanta

2012-11-01

405

Partial pressure analysis of plasmas  

SciTech Connect

The application of partial pressure analysis for plasma diagnostic measurements is reviewed. A comparison is made between the techniques of plasma flux analysis and partial pressure analysis for mass spectrometry of plasmas. Emphasis is given to the application of quadrupole mass spectrometers (QMS). The interface problems associated with the coupling of a QMS to a plasma device are discussed including: differential-pumping requirements, electromagnetic interferences from the plasma environment, the detection of surface-active species, ion source interactions, and calibration procedures. Example measurements are presented from process monitoring of glow discharge plasmas which are useful for cleaning and conditioning vacuum vessels.

Dylla, H.F.

1984-11-01

406

MARINE RESEARCH Volume 61, Number 5  

E-print Network

Journal of MARINE RESEARCH Volume 61, Number 5 Wave-induced boundary mixing in a partially mixed with the shoaling lateral boundaries. The structure and energy of IWs are diagnosed with a two instability driven by the combination of mean vertical shear and internal-wave shear is thought to be the main

Kelley, Dan

407

Background factors of molar-incisor hypomineralization in a group of Finnish children.  

PubMed

Abstract Objective. Molar-Incisor Hypomineralization (MIH) is a common developmental enamel defect characterized by demarcated opacities in permanent molars and incisors. Its etiology still remains unclear. The aim of this retrospective cohort study was to assess if the socioeconomic environment of the child is associated with MIH. Materials and methods. The study was located in two rural towns and three urban cities in Finland. A total of 818 children, between 7-13 years old, were examined for MIH using the evaluation criteria in line with those of the European Academy of Paediatric Dentistry, but excluding opacities smaller than 2 mm in diameter. The mothers filled in a questionnaire which included questions related to the family's way of living (e.g. area of residency, farming, day care attendance) and socioeconomic status (family income, number of mother's school years, level of maternal education). Results. The prevalence of MIH in the study population was 17.1%. Family income, urban residency and day care attendance were associated with MIH in the univariate analysis. In the multivariate analysis using binary logistic regression, only urban residency during a child's first 2 years of life remained associated with MIH. The prevalence of MIH in urban areas was 21.3% and in rural areas 11.5% (OR = 2.18, CI = 1.35-3.53, p = 0.001). Conclusions. The prevalence of MIH was related to urban residency and could not be explained by any other factor included in the study. PMID:25005624

Wuollet, Emma; Laisi, Sakari; Salmela, Eija; Ess, Anneli; Alaluusua, Satu

2014-11-01

408

Expression of Nfic during root formation in first mandibular molar of rat.  

PubMed

The transcription factor Nfic is a key regulator during tooth development. Nfic deficient mice exhibit short and abnormal molar roots and severely deformed incisors. Dental epithelial cells, known as Hertwig's epithelial root sheath (HERS), participate in root formation. However, whether Nfic is involved in HERS-mesenchyme interaction remains unclear. In this study, the detail temporal and spatial expression pattern of Nfic during rat molar development was examined using immunohistochemistry and in situ hybridization. Nfic was detected in ameloblasts, dental follicle cells (DFCs) and dental papilla cells (DPCs), especially the DPCs close to dentin, from postnatal day 5 to day 16. Nfic expression in DPCs, DFCs and HERS cells was also examined by western blot and RT-PCR. Nfic was detected in DPCs and DFCs, but not in HERS cells. Co-culture experiment further indicated that Nfic mRNA expression in DPCs was elevated by the presence of HERS cells. Our results revealed that Nfic could be a marker gene for root odontoblasts differentiation initiation and its expression might be regulated through epithelial-mesenchymal interaction. PMID:25074584

Chen, Xiang; Chen, Guoqing; Feng, Lian; Jiang, Zongting; Guo, Weihua; Yu, Mei; Tian, Weidong

2014-12-01

409

Evaluation of formocresol, calcium hydroxide, ferric sulfate, and MTA primary molar pulpotomies  

PubMed Central

Objective: The aim of this study is to evaluate four different pulpotomy medicaments in primary molars. Materials and Methods: A total of 147 primary molars with deep caries were treated with four different pulpotomy medicaments (FC: formocresol, FS: ferric sulfate, CH: calcium hydroxide, and MTA: mineral trioxide aggregate) in this study. The criteria for tooth selection for inclusion were no clinical and radiographic evidence of pulp pathology. During 30 months of follow-up at 6-month intervals, clinical and radiographic success and failures were recorded. The differences between the groups were statistically analyzed using the Chi-square test and Kaplan-Meier analysis. Results: At 30 months, clinical success rates were 100%, 95.2%, 96.4%, and 85% in the FC, FS, MTA, and CH groups, respectively. In radiographic analysis, the MTA group had the highest (96.4%), and the CH group had the lowest success rate (85%). There were no clinical and radiographic differences between materials (P > 0.05). Conclusions: Although there were no differences between materials, only in the CH group did three teeth require extraction due to further clinical symptoms of radiographic failures during the 30-month follow-up period. None of the failed teeth in the other groups required extraction during the 30-month follow-up period. PMID:24966776

Yildiz, Esma; Tosun, Gul

2014-01-01

410

Reliability of Third Molar Development for Age Estimation by Radiographic Examination (Demirjian's Method)  

PubMed Central

Introduction: Dental age estimation methods are of particular value because teeth are highly resistant to mechanical, chemical, or physical impacts and time. Teeth are the strongest parts in the human body and are therefore very resistant to external influences, such as extreme temperatures, explosions, and other extreme conditions, which make them available for extensive postmortem periods. Aim: To correlate chronological age with dental age using Demirijian’s method. Materials and Methods: The study was carried out on 100 digital orthopantamograms (OPG) of patients in the age group of 7 to 24 years. During the analysis, Magnify’ and Ruler’ tools were used. Mandibular right third molar was used for entire study. Data collected was analysed by using SPSS software. Results: Development of third molar in all stages was found slightly earlier in males than in females, when chronological age was compared with dental age using Demirjian method. 88% subject showed statistically significant linear correlation between chronological age and developmental age using Demirjian’s method. Conclusion: The linear correlation between chronological age and dental age using to Demirjian’s method was more in age group above 16 years and less in age group below 16 years. Demirijian’s method is a reliable guide for age estimation in age group of 7 to 24 years of age. PMID:24995239

Patil, Swapnil N; Kamble, Seema D; Mowade, Tushar; Motghare, Pavan

2014-01-01

411

Molar Incisor Hypomineralization: A Study of Prevalence and Etiology in a Group of Iranian Children  

PubMed Central

Objective The aim of this study was to investigate the prevalence of molar incisor hypomineralization (MIH) and its relationship with systemic conditions in a group of Iranian children. Methods The study population comprised of 433 7-9 year olds, from four schools in Zahedan, Iran. Subjects were evaluated clinically by one examiner, and at a separate session, their mothers completed a coded medical history questionnaire. Hypo-mineralized molars and incisors were recorded based on DDE (developmental defects of enamel) index and DMFT (number of decayed, filled and missing teeth) was determined. Statistical analyses were performed using Chi-square and independent sample t-tests. Findings Fifty-five (12.7%) children showed MIH. The overall mean number of affected teeth was 0.2. The mean value of DMFT in MIH children was greater than in normal children. Demarcated opacities were the most frequent (76%) enamel defect. Mother's and child's medical problems during prenatal, perinatal and post natal period were significantly remarkable in MIH children. Conclusion The prevalence of MIH in a group of Iranian children was 12.7%. Prenatal, perinatal and post natal medical conditions were more prevalent in children affected by MIH. PMID:23056894

Ahmadi, Rahil; Ramazani, Nahid; Nourinasab, Rahmatollah

2012-01-01

412

Comparison of oral versus sublingual piroxicam during postoperative pain management after lower third molar extraction.  

PubMed

In this study, 53 patients received piroxicam, administered orally or sublingually, after undergoing removal of symmetrically positioned lower third molars, during two separate appointments. This study used a randomized, blind, cross-over protocol. Objective and subjective parameters were recorded for comparison of postoperative results for 7 days after surgery. Patients treated with oral or sublingual piroxicam reported low postoperative pain scores. The patients who received piroxicam orally took a similar average amount of analgesic rescue medication compared with patients who received piroxicam sublingually (p>0.05). Patients exhibited similar values for mouth opening measured just before surgery and immediately following suture removal 7 days later (p>0.05), and showed no significant differences between routes of piroxicam administration for swelling control during the second or seventh postoperative days (p>0.05). In summary, pain, trismus and swelling after lower third molar extraction, independent of surgical difficulty, could be controlled by piroxicam 20mg administered orally or sublingually and no significant differences were observed between the route of delivery used in this study. PMID:21144709

Trindade, P A K; Giglio, F P M; Colombini-Ishikiriama, B L; Calvo, A M; Modena, K C S; Ribeiro, D A; Dionísio, T J; Brozoski, D T; Lauris, J R P; Faria, F A C; Santos, C F

2011-03-01

413

Risk factors in the occurrence of molar-incisor hypomineralization amongst a group of Iraqi children.  

PubMed

BACKGROUND.? Despite the worldwide increasing interest in the prevalence studies of molar-incisor hypomineralization (MIH), there is still insufficient evidence to verify the aetiological factors of this condition. AIMS.? To investigate risk factors involved in the development of MIH in a group of school-aged Iraqi children. DESIGN.? Seven- to nine-year-old school children (823 of 1000 eligible, response rate of 82.3%) had their first permanent molars and incisors evaluated using the European Academy of Paediatric Dentistry evaluation criteria for MIH. Mothers completed a medical history questionnaire-based interview performed in the schools by a trained examiner. RESULTS.? For children with MIH, 6% reported no relevant medical history; the remaining 94% reported various medical conditions putatively associated with MIH compared with 70% for the non-affected group. Post-natal medical conditions (33.3%) were most frequently reported. When data were split into the possible risk effect groups, maternal psychological stress (OR, 3.24), frequent exposure to ultrasonic scans during the last gestational trimester (OR, 2.51) and birth order as a fourth sibling or later (OR, 3.17 and 5.73, respectively) were previously unreported significant risk factors and postulated as contributing to, or causing the defect. CONCLUSIONS.? Children with MIH had experienced a greater number of medical conditions than their unaffected peers with no single health event identified as a risk factor. PMID:22646757

Ghanim, Aghareed; Manton, David; Bailey, Denise; Mariño, Rodrigo; Morgan, Michael

2013-05-01

414

Is there justification for prophylactic extraction of third molars? A systematic review.  

PubMed

The present systematic review was performed to investigate if there is evidence justifying the prophylactic extraction of third molars, one of the most frequent procedures in oral surgery. A series of searches was carried out for randomized, clinical trials and systematic reviews in seven databases (MEDLINE, BBO, LILACS, Web of Science, EMBASE, BIREME and Cochrane Library), with no restrictions regarding year or language. A supplemental manual search of the references of retrieved articles was also performed. The search strategy resulted in 260 papers. Both the data extracted and the quality of each paper were evaluated independently by two reviewers. After selection based on the preestablished eligibility criteria, four papers qualified for the final analysis. A medium degree of quality and methodological consistency was found in three studies, and low quality was found in one study. No studies showed a high degree of consistency. The most significant flaw was an inadequate sample size. The results of the present review indicate a lack of scientific evidence to justify the indication of the prophylactic extraction of third molars. PMID:23538430

Costa, Moacir Guilherme da; Pazzini, Camila Alessandra; Pantuzo, Mariele Cristina Garcia; Jorge, Maria Letícia Ramos; Marques, Leandro Silva

2013-01-01

415

Identification of possible factors impacting dental students' ability to locate MB2 canals in maxillary molars.  

PubMed

This study examined the effect of the access size and straight-line path of access on third-year dental students' ability to locate a second mesiobuccal (MB2) canal in maxillary first and second molars. One hundred and six third-year dental students at one Faculty of Dentistry performed simulated root canal treatment with the aid of 2x magnification loupes on extracted teeth. A postgraduate endodontic student subsequently made a reasonable search for an untreated MB2 canal with the aid of a dental operating microscope. The mesiobuccal roots were then sectioned horizontally for determination of the canal configuration. The dental students were able to treat an MB2 canal in 15.8 percent of the teeth, but this was not associated with satisfactory access criteria. The postgraduate endodontic student identified an MB2 canal in 54.7 percent of the remaining tooth samples excluding those where the MB2 canal was found by the dental students; this represented 94.3 percent of those teeth confirmed by horizontal sectioning of the root to have an MB2 canal. The postgraduate student troughed, on average, 2.6 mm before negotiating the MB2 canal. As satisfactory access criteria and straight-line path of access did not correlate with the dental students' ability to find a second mesiobuccal canal, this result has important implications for educational goals with respect to endodontic treatment of maxillary molar teeth. PMID:24789839

Park, Ellen; Chehroudi, Babak; Coil, Jeffrey M

2014-05-01

416

Growth-Associated Changes in the Periodontal Bone and Molar Teeth of Male Rats  

PubMed Central

Here we report quantitative data associating periodontal bone variables of young conventional rats with the growth process. The hemimandibles of male rats (IIM/Fm stock, 2 to 15 wk of age.) were excised and submitted to conventional morphologic, radiologic, and histologic evaluation. The length, area, or X-ray absorbance of various regions or structures was measured on digital images of radiographs by using an image-analysis program. The sum of periodontal bone areas undergoing resorption (interproximal + intraradicular) increased until 9 or 10 wk of age and decreased thereafter. Mineral accretion rates and mineral density asymptotes were not significantly different among molars. The mineral density of resorption areas in alveolar bone fitted sinusoidal kinetics, indicative of the ‘instability’ of the tissue due to its high metabolic activity. Mineral accretion rates and mineral density asymptotes were not significantly different among molars. The proportion of root length within alveolar bone exhibited a biphasic curve (minimum at 5 wk of age), due to differences in the growth rates of variables involved in its calculation (distance between the cementoenamel junction to the apex and height of the resorption areas). The distance between the cementoenamel junction and alveolar bone crest over time fitted a sigmoidal function with a point of inflection that did not differ significantly from that of body or mandible dry weight. In summary, the growth process appears to affect periodontal bone support and the distance between the cementoenamel junction and alveolar bone crest in male rats. PMID:19807966

Garcia, Maria F; Moreno, Hilda; Rigalli, Alfredo; Puche, Rodolfo C

2009-01-01

417

The chronology of second molar development in Brazilians and its application to forensic age estimation  

PubMed Central

Purpose This study investigated the possible correlation between the mineralization of the second molars and the chronological age of a sample population of the state of Paraiba, Brazil. Materials and Methods One thousand eight hundred fifty-four digitized panoramic images using a scanner of a private dental radiology service were obtained in six months. Of these, 457 were selected from patients aged 4.6 to 16 years who met certain criteria. The images were assessed twice by a radiologist with 5 years experience. A minimum interval of 30 days between the evaluations of the same patient was established. To analyze the relationship between chronological age, calcification level proposed by Demirjian et al in 1973, gender, and tooth, a multiple linear regression model was adjusted, taking age as the response variable (p<0.05). Results The gender and calcification level were significantly correlated with the age of the patients (p<0.05). There was a significant difference between the average age of the patients' upper teeth compared to the lower ones in both genders (p<0.05). The dental development occurred earlier in female individuals than in male ones, and there was no significant difference between the right and left second permanent molars. Conclusion It was observed that ethnic variables are related to certain parameters of age and sex identification in the Brazilian population, providing important information for forensic evaluations. PMID:23524859

Pontual, Andrea dos Anjos; Beltrão, Rejane Targino; Beltrão, Ricardo Villar; Pontual, Maria Luiza dos Anjos

2013-01-01

418

Obtaining Spruce Hemicelluloses of Desired Molar Mass by using Pressurized Hot Water Extraction.  

PubMed

There is growing interest in utilizing galactoglucomannan, the main hemicellulose in softwoods, for various applications such as cosmetics, pharmaceuticals, textiles, alimentary, and health products, as well as for the production of fuels. For fuel production and for using the rare sugars as platform chemicals, the hemicelluloses need to be hydrolyzed to sugar monomers, and for this purpose, low-molecular-mass extracts are favorable. However, for the other applications high molecular masses are required, which presents an even greater challenge for extraction. The ability to optimize the extraction process according to the needs of further processing, by using solely water as the solvent, is a key issue in the environmentally friendly utilization of this versatile raw material. The goal of this work is to study how the average molar mass of hemicelluloses extracted from spruce sapwood can be influenced by altering the experimental conditions. The main parameters influencing the extraction and hydrolysis of the hemicelluloses, namely, extraction time, temperature, pH, and chip size, were studied. The results show that it is feasible to develop an extraction process for harvesting spruce hemicelluloses, also of large molar masses, for industrial applications by using pressurized hot water extraction. PMID:25169811

Rissanen, Jussi V; Grénman, Henrik; Xu, Chunlin; Willför, Stefan; Murzin, Dmitry Yu; Salmi, Tapio

2014-10-01

419

Effect of Erythrina mulungu on anxiety during extraction of third molars  

PubMed Central

Objectives: The aim of the present study was to evaluate the effect of Erythrina mulungu on the control of dental anxiety in patients who had under gone bilateral extraction of asymptomatic, impacted mandibular third molars. Material and Methods: In a randomized, double-blind, crossover study, 30 healthy volunteers (5 men and 25 women, over 18 years of age), received either 500mg of E.mulungu (Mulungu Matusa®) or 500 mg of placebo, p.o., one hour before surgical procedure. The level ofanxiety was assessed through questionnaire sand physical parameters, such as blood pressure, heart rate andoxygen saturation. Data were analyzed by Chi-square test, ANOVA (Tukey test) and Friedman with significance level of 5%. Results: A higher preference (Chi-square, p = 0.0062) for E. mulungu was observed for both genders. Volunteers with higher anxiety levels tended to to prefer E. mulungu. No statistically significant differences were verified in blood pressure (one-way ANOVA, p = 0.1259), heart rate (Friedman, p> 0.05) and oxygen saturation (Friedman, p = 0.7664) among periods and types of treatments. Conclusions: E. mulungu showed an anxiolytic effect without significant changes in physiological parameters. It could be considered as an alternative to control the anxiety in adult patients undergoing mandibular thirdmolars surgery. Key words:Anxiety, Erythrina mulungu, third molar, oral surgery. PMID:24880443

Silveira-Souto, Maria L.; Sao-Mateus, Carla R.; Groppo, Francisco C.

2014-01-01

420

Iron deficiency after partial gastrectomy  

Microsoft Academic Search

Iron-deficiency anaemia will develop in half the males and nearly all females after partial gastrectomy, and in addition to causing the anaemia the sideropenia may cause any general symptoms such as lassitude, failure to maintain weight, or dumping symptoms.The variable response to treatment is due to the fact that ferrous iron is not adequately released from coated tablets taken after

J. R. Hobbs

1961-01-01

421

Myopathy in acquired partial lipodystrophy  

Microsoft Academic Search

We describe two women with acquired partial lipodystrophy, one with significant myopathic symptoms and signs. Muscle biopsy of deltoid and quadriceps was performed in each case. The light microscopy findings were of type 1 and type 2 fibre hypertrophy, with an increase in intracytoplasmic fat in both cases. Electron microscopy showed normal fibres, with accumulations of electron-lucent fat droplets between

Richard W. Orrell; Richard C. Peatfield; Carole E. Collins; David F. Woodrow; Jill Moss

1995-01-01

422

Partial duplication of the scapula  

Microsoft Academic Search

We report an extremely rare case of partial scapular duplication. Mild shoulder area deformity in a newborn prompted further evaluation that included radiography, ultrasonography and spiral CT. These revealed an additional bone in the area of the left shoulder, above the humerus and lateral to the scapula. The accessory bone articulated with the upper part of the glenoid and caused

Natalia Simanovsky; Nurith Hiller; Naum Simanovsky

2006-01-01

423

Partially Opened Oven on Phoenix  

NASA Technical Reports Server (NTRS)

This view from the Robotic Arm Camera on NASA's Phoenix Mars Lander shows partial opening of doors to one of the tiny ovens of the Thermal and Evolved-Gas Analyzer.

Each oven has a pair of spring-loaded doors. Near the center of the image, the partial opening of a pair of doors reveals screen over the opening where a soil sample will be delivered. The door to the right is fully opened and the one to the left is partially deployed. The doors are 10 centimeters (4 inches) long. The opening is 4 centimeters (1.5 inches) wide.

Tests on the Phoenix testbed at the University of Arizona, Tucson, indicate that a soil sample could be delivered into the oven through the partially opened doors. Engineers are also exploring possibilities for opening the doors more completely.This image was taken during Phoenix's eighth Martian day, or sol (June 2, 2008).

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

2008-01-01

424

Management of partial segmental priapism.  

PubMed

We report the cases of 2 patients with partial segmental priapism. The patients presented with pain, a perineal mass, and proximal segmental corporal thrombosis. Treatment consisted of a proximal corpus cavernosal-spongiosum shunt. Diagnostic considerations, literature review, and treatment options are discussed. PMID:11164175