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1

Partial Molar Volumes for Lanthanide Sesquioxides in Sodium Silicate Melts  

NASA Astrophysics Data System (ADS)

Lanthanides are of great interest in igneous petrology as trace indicators of magmatic processes that control the origin and evolution of igneous rocks. A key to the petrogenetic modelling of magmatic processes and to determine the phase diagrams of lanthanide host phases is the accurate determination of the physico-chemical and thermodynamic properties of lanthanide-containing materials, such as the volumetric properties of lanthanide-bearing silicate melts. Therefore, we have undertaken to provide a new reliable volumetric data set for lanthanide-bearing silicate melts which allows the available models in the literature to be extended to lanthanide-bearing melts. For this purpose, the densities of various lanthanide-bearing silicate melts distributed along various pseudo-binary joins, where the end-members are Na-disilicate and one of the lanthanide sesquioxides (i.e., Ce2O3, Pr2O3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3, Tm2O3 and Yb2O3), have been measured using the double-bob Archimedean method. The present results show that the addition of any lanthanide to Na-disilicate leads to an increase in the melt density and that the melt density increases with increasing atomic number of the lanthanide. From the present density data set, the molar volumes of these melts have been calculated and the partial molar volumes of each lanthanide sesquioxide in these melts have been determined using a linear regression through each pseudo-binary join (i.e., Na-disilicate - lanthanide sesquioxide). This study indicates ideal behaviour with respect to the molar volume (i.e., a linear variation of the molar volume along each pseudo-binary join) for Na-silicate melts containing up to 10 mol% of lanthanide oxide. Comparison between the partial molar volumes of lanthanide sesquioxides obtained in this study and the molar volumes of molten lanthanide sesquioxides given in the literature raise the possibility however that this ideality is not maintained along the entire Na-disilicate - lanthanide sesquioxide pseudo-binary joins. Excess volumes of mixing appear to be required to describe the combined volumetric data set.

Courtial, P.; Dingwell, D. B.

2004-12-01

2

The partial molar volumes of anesthetics in lipid bilayers.  

PubMed

The excess volumes of mixing of benzyl alcohol, halothane, and methoxyflurane in water and in suspensions of several lipid bilayers have been determined at 25 degrees C using a novel excess volume dilatometer. The excess volumes of mixing in water were all found to be negative, whereas in lipid suspensions they were all more positive than those in water alone. From known partition coefficients the partial molar volumes of these three solutes in the lipid bilayers were calculated. These values were all close to the molar volumes of the pure anesthetics, as was a value determined for halothane in olive oil. Halothane was studied in dipalmitoylphosphatidylcholine below its phase transition, and was found to exhibit a much larger excess volume than in any other system we studied. The potency of these three anesthetics was determined in tadpoles. It was calculated that at equi-anesthetic doses these three agents caused an expansion in egg lecithin/cholesterol (2:1) bilayers of 0.21 +/- 0.015%. This result is consistent with the hypothesis that general anesthetics act by expanding membranes. PMID:6895321

Kita, Y; Bennett, L J; Miller, K W

1981-09-21

3

Partial molar volumes of sulfur dioxide in organic solvents: Formation of charge-transfer complexes  

Microsoft Academic Search

New apparatus for measuring the apparent molar volumes of gases in liquids is described. The apparatus has been used to obtain the limiting partial molar volume of sulfur dioxide in 17 organic solvents. The limiting partial molar volume of sulfur dioxide is found to be significantly smaller in electron-donating solvents that in non-electron-donating solvents, with this difference being interpreted in

John F. Smith; Gerald A. Bottomley; Leslie Barta; Loren G. Hepler

1990-01-01

4

Partial molar volumes in aqueous mixtures of nonelectrolytes. II. Isopropyl alcohol  

Microsoft Academic Search

Densities of isopropyl alconol-water mixtures were measured over the entire mole fraction range at 5, 15, 25, 35 and 45°C. Apparent and partial molar volumes and partial molar expansibilities were derived for both components. The results were compared with those of a previous investigation of t-butyl alcohol-water mixtures.

Masao Sakurai

1988-01-01

5

Partial molar volumes of uni-univalent electrolytes in methanol + water; 1: Lithium chloride, sodium chloride, and potassium chloride  

SciTech Connect

Densities of methanol + water + lithium chloride, + sodium chloride, and + potassium chloride were measured at 15, 25, 35, and 45 C. The apparent molar volumes of the electrolytes in these mixtures were calculated, and the apparent molar volumes at infinite dilution, the partial molar volumes, and partial molar thermal expansivities were evaluated.

Takenaka, Nobuo; Takemura, Takeshi; Sakurai, Masao (Hokkaido Univ., Sapporo (Japan). Research Inst. for Electronic Science)

1994-04-01

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

The standard partial molar volumes of ions in solution. Part 5. Ionic volumes in water at 125-200 °C.  

PubMed

The standard partial molar volumes, V(?)(i,T), of 12 univalent ions (alkali metal, ammonium, halide, nitrate, and perchlorate) and five divalent ions (alkaline earth and sulfate) in water at 125, 150, 175, and 200 °C and at 2 MPa were derived from the data of Ellis. Similar data for NH(4)(+) and NO(3)(-) at 0-100 °C, not included in Part 4, were added, derived from his data too. The (negative) electrostrictive volumes, ?V(elstr)(i,T), of these ions at infinite dilution were obtained from the shell-by-shell calculation of the electrostriction according to Marcus and Hefter that takes into account the mutual dependence of the relative permittivity of the water around the ion and the electrical field strength at it. The expanded volumes of the ions, defined as V(Expan)(i,T) = V(?)(i,T) - ?V(elstr)(i,T), were then derived and compared with their intrinsic volumes, calculated according to Glueckauf. The calculation yields also the spatial extension of the dielectrically saturated region around the ions. The numbers of water molecules, the molar volume of which is affected by the ions at infinite dilution, were estimated from the ratio of ?V(elstr)(i,T) and V(Wel)(T), the latter being the average molar electrostriction of the water in the vicinity of the ions. PMID:22616975

Marcus, Yizhak

2012-06-06

8

Dependences of molar volumes in solids, partial molal and hydrated ionic volumes of alkali halides on covalent and ionic radii and the golden ratio  

Microsoft Academic Search

New linear dependences are presented here for the volumes of alkali halides in crystals and in aqueous solutions: (1) the molar volumes in solids (VBo) and the partial molal volumes (?Vo) in aqueous solutions on the sums of crystal ionic volumes, V(M+,X?)cr, (2) ?Vo on VBo, (3) ?Vo on the sum of aqueous ionic volumes, V(M+,X?)aq and (4) ?Vo, VBo,

Raji Heyrovska

2007-01-01

9

Correlation and prediction of infinite-dilution partial molar volumes of organic solutes in SC CO 2 using the Peng-Robinson and PHCT equations of state and the LCVM EOS\\/G E model  

Microsoft Academic Search

An extensive infinite-dilution partial molar volume (PMV) data base of various liquid and solid solutes in supercritical carbon dioxide, including the very recent experimental partial molar volume data reported by Spicka et al. [B. Spicka, A. Cortesi, M. Fermeglia, I. Kikic, Determination of partial molar volumes at infinite dilution using SFC technique, J. Supercrit Fluids 7 (1994) 171] and Cortesi

Ph Coutsikos; K Magoulas; D Tassios; A Cortesi; I Kikic

1997-01-01

10

Limiting Partial Molar Volumes of Electrolytes in 2Methyl2Butanol + Water Mixtures at 298.15 K  

Microsoft Academic Search

Partial molar volumes at infinite dilution, V02, of alkali–metal halides (LiCl, NaCl KCl RbCl CsCl, NaBr, KBr, KI), tetra-n-alkylammonium bromides, R4NBr (R=Me, Et, n-Pr, n-Bu, n-Pen), NaBPh4, and Ph4PCl have been determined in binary solvent mixtures of water with 2-methyl-2-butanol covering the water-rich region and the alcohol-rich region at 298.15 K. V02 for alkali–metal halides show relatively little dependence on

Eugenio Garcia-Pañeda; Pilar Guardado; Alfredo Maestre

2004-01-01

11

Enthalpies of solution, partial molar volumes and isentropic compressibilities of polycyclic aromatic hydrocarbons in 1-methyl-2-pyrrolidone at 298.15 K  

Microsoft Academic Search

In order to explain the solvation behavior of polycyclic aromatic hydrocarbons in polar solvents, the enthalpies of salvation, ?solvH, the partial molar volumes at infinite dilution, Vm,1?, and the partial molar isentropic compression at infinite dilution, Ks,m,1?, have been determined for some polycyclic aromatic hydrocarbons in 1-methyl-2-pyrrolidone (NMP) from measurements of enthalpies of solution, ?solnH, densities and sound velocities. UV-spectra

Takuya Sugiura; Hideo Ogawa

2009-01-01

12

Partial Molar Volumes of Some of ?-Amino Acids in Binary Aqueous Solutions of MgSO 4 ·7H 2 O at 298.15 K  

Microsoft Academic Search

The apparent molar volume, V\\u000a o\\u000a ?, 2, of glycine, alanine, ?-amino-n-butyric acid, valine and leucine have been determined in aqueous solutions of 0.25, 0.5 and 1.0 mol?dm?3 magnesium sulfate, and the partial specific volume from density measurements at 298.15 K. These data have been used to calculate the infinite dilution apparent molar volume, V\\u000a o\\u000a 2,m\\u000a , group contribution

Bairagi C. Mallick; Nand Kishore

2006-01-01

13

Standard partial molar volumes of aqueous glycolic acid and tartaric acid from 25 to 350 degrees C: evidence of a negative Krichevskii parameter for a neutral organic solute.  

PubMed

Apparent molar volumes have been determined using a high-pressure vibrating-tube densimeter for aqueous solutions of glycolic acid (HGly = HOCH(2)COOH) and tartaric acid (H(2)Tar = HOOCCH(OH)CH(OH)COOH) at temperatures from 25 degrees C to 350 degrees C and pressures as high as 20 MPa. The resulting standard partial molar volumes (HGly,aq) are relatively independent of temperature until 315 degrees C, at which point (HGly,aq) deviates sharply toward negative values. This suggests that the Krichevskii parameter, A(Kr) = lim(x(2) --> 0) , which describes the discontinuities in standard partial molar properties at the critical point of water, is negative. Almost all aqueous nonelectrolytes are characterized by positive Krichevskii parameters. This is the first negative value reported for any organic molecule that is not an ion or zwitterion and only the third ever observed directly for a neutral species (the others are B(OH)(3) and H(3)PO(4)). The standard partial molar volumes for H(2)Tar(aq) are also relatively independent of temperature until 275 degrees C, suggesting a similar behavior. However, the onset of thermal decomposition prevented measurements at temperatures above 300 degrees C. PMID:16853658

Bulemela, E; Tremaine, Peter R

2005-11-01

14

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

2008-04-16

15

Densities and Excess, Apparent, and Partial Molar Volumes of Binary Mixtures of BMIMBF4 + Ethanol as a Function of Temperature, Pressure, and Concentration  

NASA Astrophysics Data System (ADS)

The densities of five BMIMBF4 (1-butyl-3-methylimidazolium tetrafluoroborate) + ethanol binary mixtures with compositions of (0.0701, 0.3147, 0.5384, 0.7452, and 0.9152) mole fraction BMIMBF4 and of pure BMIMBF4 have been measured with a vibrating-tube densimeter. Measurements were performed at temperatures from 298 K to 398 K and at pressures up to 40 MPa. The total uncertainty of density, temperature, pressure, and concentration measurements were estimated to be less than 0.1 kg · m-3, 15 mK, 5 kPa, and 10-4, respectively. The uncertainties reported in this article are expanded uncertainties at the 95% confidence level with a coverage factor of k = 2. The measured densities were used to study derived volumetric properties such as excess, apparent, and partial molar volumes. It is shown that the values of excess molar volume for BMIMBF4 + ethanol mixtures are negative at all measured temperatures and pressures over the whole concentration range. The effect of water content on the measured values of density is discussed. The volumetric (excess, apparent, and partial molar volumes) and structural (direct and total correlation integrals, cluster size) properties of dilute BMIMBF4 + ethanol mixtures were studied in terms of the Krichevskii parameter. The measured densities were used to develop a Tait-type equation of state.

Abdulagatov, I. M.; Tekin, A.; Safarov, J.; Shahverdiyev, A.; Hassel, E.

2008-04-01

16

Partial molar heat capacities and volumes of transfer of some saccharides from water to aqueous sodium chloride solutions at T=298.15 K  

Microsoft Academic Search

Partial molar heat capacities (Cop,2,m) and volumes (Vo2,m) of seven monosaccharides, namely, d(?)-ribose, d(?)-arabinose, d(+)-xylose, d(+)-glucose, d(+)-mannose, d(+)-galactose, and d(?)-fructose; five disaccharides, namely, sucrose, d(+)-cellobiose, d(+)-maltose monohydrate, d(+)-lactose monohydrate, d(+)-trehalose dihydrate, and one trisaccharide, d(+)-raffinose pentahydrate, have been determined in NaCl(aq), m=(1.0, 2.0, and 3.0)mol·kg?1 at T=298.15K from volumic heat capacity and density measurements employing a Picker flow microcalorimeter and

B. S. Lark; T. S. Banipal; J. C. Ahluwalia

2002-01-01

17

Partial excess molar volumes, partial excess isentropic compressibilities and relative permittivities of water + ethane-1,2-diol derivative and water + 1,2-dimethoxyethane at different temperatures  

Microsoft Academic Search

Experimental densities, ?, speed of sound, ? and relative permittivities, ?r for four binary mixtures of water + (monomeric, dimeric and trimeric) forms of ethane-1,2-diol and + 1,2-dimethoxyethane were measured over the mole fraction and at different temperatures. The excess molar volumes, VmE, excess isentropic compressibilities, ?sE and deviations in relative permittivities, ??r were calculated and the data was smoothed

J George; N. V Sastry

2004-01-01

18

Limiting Partial Molar Volume of Sodium Chloride in 2Methyl2,4-pentandiol-Water Mixed Solvents at 25 °C  

Microsoft Academic Search

Herein we report density measurements for the binary system 2-methyl-2,4-pentanediol(MPD,1)-water(0), and for the ternary system MPD(1)-NaCl(2)-water(0), at several fixed MPD\\/water ratios and at varying NaCl concentrations. The partial molar volume of MPD in the binary system has been discussed according to the McMillan-Meyer theory. At low MPD concentrations, the non-bonding MPD-MPD interactions are related to the overlapping of the hydrophobic

F. Capuano; G. Mangiapia; G. D’Errico; R. Sartorio

2006-01-01

19

Partial molar volumes of l-alanine, dl-serine, dl-threonine, l-histidine, glycine, and glycylglycine in water, NaCl, and DMSO aqueous solutions at T = 298.15 K  

Microsoft Academic Search

The apparent molar volumes of l-alanine, dl-serine, dl-threonine, l-histidine, glycine, and glycylglycine in water and in the aqueous solutions of NaCl and DMSO with various concentrations at T=298.15 K have been measured by the precise vibrating-tube digital densimeter. The calculated partial molar volumes at infinite dilution have been used to obtain corresponding transfer volumes from water to various solutions. The

Quan Yuan; Zhi-Fen Li; Bao-Huai Wang

2006-01-01

20

The Partial Molar Volumes and Heat Capacities of the Arginyl Side-chain of Proteins in Aqueous Solution over the Temperature Range 288.15 to 328.15 K  

Microsoft Academic Search

Solution densities over the temperature range 288.15 to 328.15 K have been measured for aqueous solutions of N-acetylarginamide monotrifluoroacetate and sodium trifluoroacetate, from which the partial molar volumes at infinite dilution,\\u000a , were determined. The partial molar heat capacities at infinite dilution, , were also determined for these solutes over the same temperature range. These and results, along with relevant data

Gavin R. Hedwig; Andrew W. Hakin

2010-01-01

21

Partial molar volumes at infinite dilution in aqueous solutions of NaCl, LiCl, NaBr, and CsBr at temperatures from 550 K to 725 K  

Microsoft Academic Search

Partial molar volumes at infinite dilution provide a convenient test of theoretical models of aqueous solutions. In this communication, previously published experimental results of the apparent molar volumes for NaCl, NaBr, LiCl, and CsBr at near-critical conditions were extrapolated to infinite dilution. In the temperature range included in this study (550 to 725) K, ionic association processes must be considered.

Josef Sedlbauer; Eric M. Yezdimer; Robert H. Wood

1998-01-01

22

Experimental and Theoretical Determination of the Limiting Partial Molar Volume of Indole in CCl 4 , Tetrahydrofuran and Acetonitrile at 293.15 K: A Comparative Study with Benzimidazole and Benzothiophene  

Microsoft Academic Search

The partial molar volumes of indole(Ind) at infinite dilution () in carbon tetrachloride (CCl4), acetonitrile (ACN) and tetrahydrofuran (THF) as solvents, were estimated from densitometry measurements at 293.15 K. The\\u000a results indicate that V_{2}^{\\\\infty}\\\\mbox{(CCl$_{4}$)}$\\

Ysaías J. Alvarado; Néstor Cubillán; Esker Chacín-Molero; Gladys Ferrer-Amado; Paola Hernández-Labarca; Wendy Velazco; José Ojeda-Andara; Yovani Marrero-Ponce; Federico Arrieta

2010-01-01

23

The molar volume of silicon [Avogadro constant  

Microsoft Academic Search

A reevaluation has been made of the density and molar mass data for the silicon single crystals used in three Avogadro projects in which the authors' institutions are cooperating. A value of 12.058 825(15) cm 3 mol-1 at 22.5°C was obtained for the ratio M(Si)\\/?(Si), which is considered our present best estimate of the silicon molar volume. This implies for

P. De Bievre; S. Valkiers; R. Gonfiantini; P. D. P. Taylor; H. Bettin; F. Spieweck; A. Peuto; S. Pettorruso; M. Mosca; K. Fujii; M. Tanaka; Y. Nezu; A. J. Leistner; W. J. Giardini

1997-01-01

24

Partial molar quantity of an intensive mother function  

NASA Astrophysics Data System (ADS)

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 ?ni 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 = [??/{?ni/(N + ?ni)

Koga, Yoshikata

2012-09-01

25

40 CFR Table 1 to Subpart Ja of... - Molar Exhaust Volumes and Molar Heat Content of Fuel Gas Constituents  

Code of Federal Regulations, 2013 CFR

...Molar Exhaust Volumes and Molar Heat Content of Fuel Gas Constituents...PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance...Molar Exhaust Volumes and Molar Heat Content of Fuel Gas Constituents...atmosphere. b MHC = molar heat content (higher heating...

2013-07-01

26

Partial Molar and Ultrasonic Properties of Benzoic and Phenyl Acetic Acids in Water and Water + Alcohol Mixtures  

Microsoft Academic Search

Partial molar volumes of Benzoic and Phenylacetic acids have been determined in water and water + alcohol (5 wt% each of methanol, ethanol and propanol) mixtures from density measurements in varying ranges of concentration at four different temperatures in the interval of 10° from 288.15 to 318.15 K. The density data have been used to obtain partial molar volumes, co-efficients

U. N. Dash; B. K. Mohanty

1999-01-01

27

Apparent and standard partial molar volumes of NaCl, NaOH, and HCl in water and heavy water at T = 523 K and 573 K at p = 14 MPa.  

PubMed

Apparent molar volumes, Vphi,2, of aqueous NaCl, NaOH, NaOD, HCl, and DCl in water and heavy water were determined at T = 523 and 573 K and p = 14 MPa with a high-temperature platinum vibrating-tube densimeter in the aquamolality range 0.25 partial molar volumes of these electrolytes in light and heavy water, V degrees 2,H and V degrees 2,D, respectively. For NaCl and NaOH, the D2O isotope effect at infinite dilution, [V degrees 2,H - V degrees 2,D], increases from 0.2 and 0.8 cm3 mol-1 to 4.5 and 7.1 cm3 mol-1, respectively, when the temperature is increased from 523 to 573 K. For HCl and DCl, the effect is smaller and the sign is reversed, [V degrees 2,H - V degrees 2,D] = -0.7 cm3 mol-1 at 523 K and -1.4 cm3 mol-1 at 573 K. When the effect of ion association is included, the deuterium isotope effect for HCl becomes positive, [V degrees 2,H - V degrees 2,D] approximately 17 cm3 mol-1 at 573 K, consistent with NaCl and NaOH. Two models are proposed to describe the solvent isotope effect on the infinite dilution limit, one based on the Born equation and the other on the dimensionless Krichevskii parameter. The experimental values of V degrees 2,D also have been used to calculate the first reported values for the pressure dependence of the ionization constant of D2O at temperatures higher than 313 K. PMID:17274641

Trevani, Liliana N; Balodis, Erik C; Tremaine, Peter R

2007-02-03

28

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

29

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

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

Partial molar isentropic pressure coefficients of some N-acetyl amino acid and peptide amides at infinite dilution in aqueous solutions at the temperature 298.15 K  

Microsoft Academic Search

The partial molar isentropic pressure coefficients at infinite dilutionk?S,2= ?(?V?\\/?p)S, whereV?2is the partial molar volume at infinite dilution, have been determined for sixN-acetyl amino acid and peptide amides in aqueous solution at the temperature 298.15 K. The results obtained have been rationalized in terms of the likely solute — water interactions. The contribution of an alanyl side-chain to the value

Gavin R. Hedwig; Harald Høiland

1995-01-01

32

Molecular representation of molar domain (volume), evolution equations, and linear constitutive relations for volume transport.  

PubMed

In the traditional theories of irreversible thermodynamics and fluid mechanics, the specific volume and molar volume have been interchangeably used for pure fluids, but in this work we show that they should be distinguished from each other and given distinctive statistical mechanical representations. In this paper, we present a general formula for the statistical mechanical representation of molecular domain (volume or space) by using the Voronoi volume and its mean value that may be regarded as molar domain (volume) and also the statistical mechanical representation of volume flux. By using their statistical mechanical formulas, the evolution equations of volume transport are derived from the generalized Boltzmann equation of fluids. Approximate solutions of the evolution equations of volume transport provides kinetic theory formulas for the molecular domain, the constitutive equations for molar domain (volume) and volume flux, and the dissipation of energy associated with volume transport. Together with the constitutive equation for the mean velocity of the fluid obtained in a previous paper, the evolution equations for volume transport not only shed a fresh light on, and insight into, irreversible phenomena in fluids but also can be applied to study fluid flow problems in a manner hitherto unavailable in fluid dynamics and irreversible thermodynamics. Their roles in the generalized hydrodynamics will be considered in the sequel. PMID:19044872

Eu, Byung Chan

2008-09-01

33

Excess molar volumes and apparent molar volumes of some amide + water systems at 303.15 and 308.15 K  

SciTech Connect

Excess molar volumes V{sub m}{sup E} for the binary mixtures of N-methylformamide, N,N-dimethylformamide, 2-pyrrolidinone, N-methyl-2-pyrrolidinone, and N,N-dimethylacetamide with water have been measured using a continuous-dilution dilatometer at 303.15 and 308.15 K as a function of composition. In all mixtures, the excess molar volumes are negative over the entire composition range. The results were used to estimate the apparent molar volumes of the components. The values of these two properties have been discussed in terms of intermolecular interactions between the mixing components of the binary mixture.

Pal, A.; Singh, Y.P. [Univ. of Kurukshetra (India). Dept. of Chemistry

1995-07-01

34

Evaluation of the molar volume of silicon crystals for a determination of the Avogadro constant  

Microsoft Academic Search

For a determination of the Avogadro constant by the X-ray crystal density method, the molar volume of three different silicon crystals has been evaluated by absolute measurements of their densities and molar masses. The results have shown that the molar volume is 12.058 8279 (22) cm3 mol-1. When this value is combined with the lattice constant recommended by the CODATA

Kenichi Fujii; Atsushi Waseda; Naoki Kuramoto; Shigeki Mizushima; Mitsuru Tanaka; Staf Valkiers; Philip Taylor; Rüdiger Kessel; Paul De Bievre

2003-01-01

35

A reassessment of the molar volume of silicon and of the Avogadro constant  

Microsoft Academic Search

An “absolute” value for the molar volume of Si in Si single crystals is presented as 12.058 820 7(54) cm3 mol-1 with a relative standard uncertainty of 4.5·10 -7. It is argued that the consistency of most of the molar volume determinations is useful for evaluating the quality of the Si single crystals involved. A value for the Avogadro constant

Paul De Bièvre; Staf Valkiers; Rüdiger Kessel; Philip D. P. Taylor; Peter Becker; H. Bettin; Anna Peuto; Savino Pettorruso; K. Fujii; A. Waseda; M. Tanaka; R. D. Deslattes; H. S. Peiser; M. J. Kenny

2001-01-01

36

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.

37

Changes in Apparent Molar Water Volume and DKP Solubility Yield Insights on the Hofmeister Effect  

PubMed Central

This study examines the properties of a 4 × 2 matrix of aqueous cations and anions at concentrations up to 8.0 M. The apparent molar water volume, as calculated by subtracting the mass and volume of the ions from the corresponding solution density, was found to exceed the molar volume of ice in many concentrated electrolyte solutions, underscoring the non-ideal behavior of these systems. The solvent properties of water were also analyzed by measuring the solubility of diketopiperazine (DKP) in 2.000 M salt solutions prepared from the same ion combinations. Solution rankings for DKP solubility were found to parallel the Hofmeister series for both cations and anions, whereas molar water volume concurred with the cation series only. The results are discussed within the framework of a desolvation energy model that attributes solute-specific changes in equilibria to solute-dependent changes in the free energy of bulk water.

Payumo, Alexander Y.; Huijon, R. Michael; Mansfield, Deauna D.; Belk, Laurel M.; Bui, Annie K.; Knight, Anne E.; Eggers, Daryl K.

2011-01-01

38

Apparent Molar Volume and Viscosity Studies on Some Carbohydrates in Solutions  

Microsoft Academic Search

Summary.  ?The apparent molar volume (?v) and viscosity (?) of L(+)-arabinose, D(+)-galactose, D(?)-fructose, D(+)-glucose, sucrose, lactose, and maltose in water and in 0.1% and 0.3% water-Surf Excel solutions were measured as a function\\u000a of solute concentrations at 308.15, 313.15, and 323.15?K, respectively. The apparent molar volume (?v) of the carbohydrates was found to be a linear function of the concentration. From

Parimal C. Dey; Muhammad A. Motin; Tapan K. Biswas; Entazul M. Huque

2003-01-01

39

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.

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

2009-01-01

40

Thermodynamic properties of peptide solutions. Part 11. Partial molar isentropic pressure coefficients in aqueous solutions of some tripeptides that model protein side-chains.  

PubMed

The partial molar isentropic pressure coefficients at infinite dilution K infinity s,2 (K infinity s,2 = -(delta V infinity 2/delta p)s, where V infinity 2 is the partial molar volume at infinite dilution) have been determined for nine tripeptides in aqueous solution at 25 degrees C. The tripeptides are all of sequence glycyl-X-glycine, where X is an amino acid. These K infinity s,2 results, in conjunction with those of glycylglycylglycine, were used to estimate the amino acid side-chain contributions to K infinity s,2 of peptides. These side-chain contributions are critically compared with previous estimates based on K infinity s,2 data for the amino acids. The variation in the side-chain contributions derived using the peptide K infinity s,2 results has been rationalized in terms of likely peptide-solvent interactions. PMID:8155817

Hedwig, G R; Høiland, H

1994-03-01

41

Determination of the Molar Volume of Hydrogen from the Metal-Acid Reaction: An Experimental Alternative.  

ERIC Educational Resources Information Center

|Describes an alternative technique for determining the molar volume of hydrogen from the metal-acid reaction in which the metal sample is encased in a specially prepared cage and a pipette filler is used to fill an inverted burette with water. Eliminates some difficulties encountered with the conventional technique. (JRH)|

de Berg, Kevin; Chapman, Ken

1996-01-01

42

Toward the Avogadro Constant - Preliminary Results on the Molar Volume of Silicon  

Microsoft Academic Search

The silicon molar volume has been measured through Atomic Weight and density measurements. Mass spectrometric determination of the isotopic composition was performed on two differently grown samples. Density of specimens from the same crystals was obtained through mass and direct dimension measurements on single crystal spheres.

A. Sacconi; A. Peuto; G. Lenaers; S. Valkiers; P. De Bievre

1988-01-01

43

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) 4 2- , Al(OH) 4 - , Zn(OH) 4 2- , 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

44

Strongly Composition-Dependent Partial Molar Compressibility of Water in Silicate Glasses  

NASA Astrophysics Data System (ADS)

Water and other volatiles have long been known to play a fundamental role in igneous processes, yet their influence on the physical properties of melts are still not well enough understood. Of particular interest is the density contrast between liquid and solid phases, which facilitates melt extraction and migration. Owing to its low molecular weight, dissolved water must decrease magma density, but the way it does so as a function of pressure remains largely to be determined. Studies on quenched melts (glasses) provide useful information because the glass has the same structure as the melt. We measured compressional and shear wave velocities of seven series of hydrous aluminosilicate glasses by Brillouin scattering at room temperature and pressure. The glasses were quenched from high temperature and 2 or 3 kbar pressure. The dry end-members range from highly polymerized albitic and granitic compositions, to depolymerized synthetic analogues of mantle-derived melts. For each set of glasses, the adiabatic shear and bulk moduli have been calculated from the measured sound velocities and densities. These moduli are linear functions of water content up to 5 wt % H2O, the highest concentration investigated, indicating that both are independent of water speciation in all series. For water-free glasses, the bulk modulus decreases from about 65 to 35 GPa with increasing degree of polymerization. Sympathetically, the partial molar bulk modulus of the water component decreases from 114 to 8 GPa, such that dissolved water amplifies the differences in rigidity between the anhydrous glasses. This strong variation indicates that the solubility mechanisms of water depend strongly on silicate composition. Depolymerized liquids are also much less compressible than their polymerized counterparts, suggesting that the partial molar compressibility of dissolved water approaches zero in depolymerized liquids. If this is correct, hydrous mantle melts formed beneath volcanic arcs would be more buoyant at depth than previously thought, facilitating their extraction and rapid ascent.

Whittington, A. G.; Richet, P.; Polian, A.

2010-12-01

45

Partial volume correction using reverse diffusion  

NASA Astrophysics Data System (ADS)

Many medical images suffer from the partial volume effect where a boundary between two structures of interest falls in the middle of a voxel giving a signal value that is a mixture of the two. We propose a method to restore the ideal boundary by splitting a voxel into sub-voxels and reapportioning the signal into the sub-voxels. We designed this method to correct MRI 2D slice images where partial volume can be a considerable limitation. Each voxel is divided into four (or more) sub-voxels by nearest neighbor interpolation. The gray level of each sub-voxel is considered as "materials" able to move between sub-voxels but not between voxels. A partial differential equation is written to allow the material to flow towards the highest gradient direction, creating a "reverse" diffusion process. Flow is subject to constraints that tend to create step edges. Material is conserved in the process thereby conserving MR signal. The method proceeds until the flow decreases to a low value. To test the method, synthetic images were down-sampled to simulate the partial volume artifact and restored. Corrected images were remarkably closer both visually and quantitatively to the original images than those obtained from common interpolation methods: on simulated data mean square errors were 0.35, 1.09, and 1.24 for the proposed method, bicubic, and bilinear interpolation respectively. The method was relatively insensitive to noise. On MRI physical phantom and brain images, restored images processed with the new method were visually much closer to high-resolution counter-parts than those obtained with common interpolation methods.

Salvado, Olivier; Hillenbrand, Claudia; Wilson, David L.

2005-04-01

46

Specific heats of solid natural neon at five molar volumes and of the separated neon isotopes at P =0  

Microsoft Academic Search

Direct measurements of the constant volume specific heatCvare reported for solid natural neon at several molar volumes (13.39–12.39 cm3\\/mole) at temperatures from 1 K to the melting line. All samples were solidified in a high-pressure bomb at the melting line (maximum conditions of 53 K and 2.5 kbar) and molar volumes for the melting line are given. The extrapolations of

R. Q. Fugate; C. A. Swenson

1973-01-01

47

Specific heats of solid natural neon at five molar volumes and of the separated neon isotopes at P=0  

Microsoft Academic Search

Direct measurements of the constant volume specific heat C v are reported for solid natural neon at several molar volumes (13.39 12.39 cm3\\/mole) at temperatures from 1 K to the melting line. All samples were solidified in a high-pressure bomb at the melting line (maximum conditions of 53 K and 2.5 kbar) and molar volumes for the melting line are

R. Q. Fugate; C. A. Swenson

1973-01-01

48

Prediction of excess molar volumes of binary mixtures of organic compounds from refractive indices  

Microsoft Academic Search

The excess molar volumes of 51 binary mixtures containing diverse groups of organic compounds: alcohols (methanol, ethanol,\\u000a propan-1-ol, butan-1-ol, pentan-1-ol, hexan-1-ol, and heptan-1-ol), (cyclo-) alkanes (hexane, heptane, octane, nonane, decane,\\u000a undecane, dodecane, and cyclohexane), esters (diethyl carbonate and ethyl chloroacetate), aromatics (o-xylene, m-xylene, p-xylene, and ethylbenzene), ketones (acetone), and ethers (anisole), were predicted from the refractive index data, using\\u000a three

Ivona R. Radovi?; Mirjana Lj. Kijev?anin; Marijan Z. Gabrijel; Slobodan P. Šerbanovi?; Bojan D. Djordjevi?

2008-01-01

49

Thermodynamic properties of peptide solutions: 7. Partial molar isentropic pressure coefficients of some dipeptides in aqueous solution  

Microsoft Academic Search

The partial molar isentropic pressure coefficients at infinite dilution, KS,2o, have been determined for a number of dipeptides in aqueous solution at 25°C. For a series of dipeptides of sequence gly-X, where X is an amino acid with a neutral side chain, the KS,2o values are all more negative than that for diglycine. The results are discussed in terms of

Gavin R. Hedwig; Harald Høiland

1991-01-01

50

Bubble curves and saturated liquid molar volumes for chlorofluorohydrocarbon-hydrocarbon mixtures: Experimental data and modeling  

Microsoft Academic Search

Vapor-liquid equilibria and liquid densities were obtained using a static apparatus fitted with a variable-volume cell which was described in detail by Valtz et al. (1). Results are given at four temperatures for the binary systems butane--1,2,2-trichlorotrifluoroethane, pentane--1,2-dichloro-1,1,2,2-tetrafluoroethane, hexane--1,2-dichloro-1,1,2,2-tetrafluoroethane, heptane--1,12-trichloro-1,2,2-trifluoromethane, heptane--1,2-dichloro-1,1,2,2-tetrafluoroethane, and benzene--1,2-dichloro-1,1,2,2-tetrafluoroethane and the ternary system 1,2-dichloro-1,1,2,2-tetrafluoroethane--1,1,2-trichloro-1,2,2-trifluoromethane--heptane. The best simultaneous representation of pressures and saturated liquid molar volumes at

Serge Laugier; Dominique Richon; Henri Renon

1994-01-01

51

Volume rendering in the presence of partial volume effects  

NASA Astrophysics Data System (ADS)

In tomographic images, partial volume effects (PVE) cause several artifacts in volume renditions. In x-ray CT, for example, soft-tissue-like pseudo structures appear in bone-to-air and bone-to-fat interfaces. Further, skin, which is identical to soft tissue in terms of CT number, obscures the rendition of the latter. The purpose of this paper is to demonstrate these phenomena and to provide effective solutions that yield significantly improved renditions. Here, we introduce two methods that detect and classify voxels with PVE in x-ray CT. A method is described to automatically peel skin so that PVE-resolved renditions of bone and soft tissue reveal considerably more details. In the first method, the fraction of each tissue material in each voxel v is estimated by taking into account the intensities of the voxels neighboring v. The second method is based on the following postulate (IEEE PAMI, vol. 23 pp. 689- 706, 2001): In any acquired image, voxels with the highest uncertainty occur in the vicinity of object boundaries. The removal of skin is achieved by means of mathematical morphology. Volume renditions have been created before and after applying the methods for several patient CT datasets. A mathematical phantom experiment involving different levels of PVE has been conducted by adding different degrees of noise and blurring. A quantitative evaluation is done utilizing the mathematical phantom and clinical CT data wherein an operator carefully masked out voxels with PVE in the segmented images. All results have demonstrated the enhanced quality of display of bone and soft tissue after applying the proposed methods. The quantitative evaluations indicate that more than 98% of the voxels with PVE are removed by the two methods and the second method performs slightly better than the first. Further, skin peeling vividly reveals fine details in the soft tissue structures.

Souza, Andre D.; Udupa, Jayaram K.; Saha, Punam K.

2002-05-01

52

An MRI-guided PET partial volume correction method  

Microsoft Academic Search

Accurate quantification of positron emission tomography (PET) is important for diagnosis and assessment of cancer treatment. The low spatial resolution of PET imaging induces partial volume effect to PET images that biases quantification. A PET partial volume correction method is proposed using high-resolution, anatomical information from magnetic resonance images (MRI). The corrected PET is pursued by removing the convolution of

Hesheng Wang; Baowei Fei

2009-01-01

53

Simple program calculates partial liquid volumes in vessels  

Microsoft Academic Search

This paper reports on a simple calculator program which solves problems of partial liquid volumes for a variety of storage and process vessels, including inclined cylindrical vessels and those with conical heads. Engineers in the oil refining and chemical industries are often confronted with the problem of estimating partial liquid volumes in storage tanks or process vessels. Cistern, the calculator

Koch

1992-01-01

54

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

55

Molar volume, thermal expansivity and isothermal compressibility of trans-decahydronaphthalene up to 200MPa and 446K  

NASA Astrophysics Data System (ADS)

The molar volume isotherms of trans-decahydronaphthalene (C10H18) between 293 and 446 K and at pressures from 10 to 200 MPa have been determined. A modified Tait equation of state is used to fit each experimental molar volume isotherm with a maximum average deviation of 0.029%. The thermal expansivity (cubic expansion coefficient) ? and isothermal compressibility ? were determined by fitting the slopes of the isobaric curves and isotherms, respectively. The coefficients in the equation Vm = C1+C2T+C3T2-C4p-C5pT have been fitted with an average deviation of 1.03%.

Zhu, Hu-Gang; Liu, Zhi-Hua; Tian, Yi-Ling; Xue, Yuan; Yin, Liang

2005-12-01

56

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

57

Partial specific volume of cellulose acetate  

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.

58

Partial specific volume of methyl cellulose  

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.

59

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

National Technical Information Service (NTIS)

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, w...

J. C. Seitz J. G. Blencoe D. B. Joyce R. J. Bodnar

1992-01-01

60

Differential Phase Volume Model and Amplitude Measurements of Partial Reflections.  

National Technical Information Service (NTIS)

The work presents a theoretical model of the differential phase experiment which accounts for scattering from a volume of irregularities. The expected value of the phase difference angle between ordinary and extraordinary mode partially reflected radio wa...

D. B. Newman

1974-01-01

61

Interaction of ?-lactoglobulin with ionic surfactants: Apparent molar volume and compressibility studies of ionic surfactants in aqueous solutions of ?-lactoglobulin  

Microsoft Academic Search

In this work we present apparent molar volume (?v), adiabatic compressibility (?k) and sound velocity number [U] of sodium dodecyl sulfate (SDS), sodium n-nonyl sulfate (SNS), sodium dodecyl benzene sulfonate (SDBS), cetyl trimethyl ammonium bromide (CTAB), and di (dodecyl dimethyl ammonium bromide) (12-2-12) in aqueous solution of ?-lactoglobulin (?LG) between 10 and 36°C at an interval of 2°C. The temperature

M. S. Chauhan; Rajni; K. Sharma; S. Pathania; S. Chauhan; G. Kumar

2008-01-01

62

Densities and apparent molar volumes of aqueous magnesium sulfate and sodium sulfate to 473 K and 100 bar  

Microsoft Academic Search

Densities of aqueous solutions of MgSOâ and NaâSOâ have been measured up to 473 K, 100 bar, and 1 m ionic strength. The derived apparent molar volumes along with the available literature data on these substances have been analyzed by using the ion-interaction (Pitzer) approach. V-barâ° for MgSOâ is obtained indirectly from values for MgClâ, NaâSOâ, and NaCl. The term

Ramesh C. Phutela; Kenneth S. Pitzer

1986-01-01

63

Thermodynamics for self-association of caffeine in water: apparent molar volumes and apparent molar heat capacities of aqueous caffeine at temperatures from 278.15 to 393.15 K and at the pressure 0.35 MPa  

Microsoft Academic Search

We have determined the apparent molar volumes V? and the apparent molar heat capacities Cp,? for aqueous solutions of caffeine at temperatures T from 278.15K to 393.15K, at the pressure 0.35MPa, and at molalities m from 0.01mol·kg?1 to 0.1mol·kg?1. We used a vibrating tube densimeter (DMA 512P, Anton PAAR, Austria) to determine the densities and volumetric properties, and a twin

M. L Origlia-Luster; B. A Patterson; E. M Woolley

2002-01-01

64

Apparent molar volumes of La(CF{sub 3}SO{sub 3}){sub 3}(aq) and Gd(CF{sub 3}SO{sub 3}){sub 3}(aq) at 278 K, 298 K, and 318 K at pressures to 30.0 MPa  

SciTech Connect

Densities of La(CF{sub 3}SO{sub 3}){sub 3}(aq) and Gd(CF{sub 3}SO{sub 3}){sub 3}(aq) have been measured at 278 K, 298 K, and 318 K at pressures of 0.1 MPa, 7.0 MPa, and 30.0 MPa using vibrating-tube densimeters. Apparent molar volumes obtained from the density data have been fitted to the Pitzer equation. The standard partial molar volumes V{sub {phi}}{sup {infinity}} and the ion-interaction parameters {beta}{sup (0)V} and {beta}{sup (1)V} have been determined through least-squares fitting to the experimental results. The standard partial molar volume of the trifluoromethanesulfonate anion V{sub {phi}}{sup {infinity}}(CF{sub 3}SO{sub 3}{sup {minus}},aq) was calculated at 298 K and 0.1 MPa from the partial molar volumes of the gadolinium and lanthanum salts and the available values for the standard partial molar volumes of the cations. Excellent agreement is obtained for V{sub {phi}}{sup {infinity}}(CF{sub 3}SO{sub 3}{sup {minus}},aq) calculated from the data for the two salts.

Xiao, C.; Tremaine, P.R. [Memorial Univ. of Newfoundland, St. John`s, Newfoundland (Canada). Dept. of Chemistry; Simonson, J.M. [Oak Ridge National Lab., TN (United States). Chemical and Analytical Sciences Div.

1996-09-01

65

Quantifying the Partial Volume Effect in PET Using Benford's Law  

Microsoft Academic Search

Partial volume (PV) correction techniques in PET or SPECT represents a key step in image quantification methods. The PV effect arises because of the blurring induced by the imaging system's point spread function (PSF), producing intra-voxel mixing of the signals arising from different functional tissue classes. Quantification of this effect is often required to recover the mixing components within a

Kevin Wells; John Chiverton; Mike Partridge; Miriam Barry; Haval Kadhem; Bob Ott

2007-01-01

66

Brain PET Partial-Volume Compensation Using Blurred Anatomical Labels  

Microsoft Academic Search

Clinical use of positron emission tomography (PET) for brain imaging is limited by the partial-volume effect (PVE) induced by the limited spatial resolution of most scanners. Correction for this effect is often performed using a post-reconstruction processing framework involving external information provided by an MRI acquisition. This approach has the major drawback of being very sensitive to the unavoidable MRI

F. Bataille; C. Comtat; S. Jan; F. C. Sureau; R. Trebossen

2007-01-01

67

Brain PET Partial-Volume Compensation Using Blurred Anatomical Labels  

Microsoft Academic Search

Clinical use of positron emission tomography (PET) for brain imaging is limited by the partial-volume effect (PVE) induced by the limited spatial resolution of most scanners. Correction for this effect is usually performed using a post-reconstruction processing framework involving external information provided by an MRI acquisition. This approach has the major drawback of being very sensitive to the unavoidable MRI

F. Bataille; C. Comtat; S. Jan; F. C. Sureau; R. Trebossen

2006-01-01

68

Molar volume, excess enthalpy, and Prigogine-Defay ratio of some silicate glasses with different (P,T) histories  

NASA Astrophysics Data System (ADS)

Structural relaxation in silicate glasses with different (p,T) histories was experimentally examined by differential scanning calorimetry and measurements of molar volume under ambient pressure. Temperature and pressure-dependent rates of changes in molar volume and generation of excess enthalpy were determined for sodium trisilicate, soda lime silicate, and sodium borosilicate (NBS) compositions. From the derived data, Prigogine-Defay ratios are calculated and discussed. Changes of excess enthalpy are governed mainly by changes in short-range structure, as is shown for NBS where boron coordination is highly sensitive to pressure. For all three glasses, it is shown how the relaxation functions that underlie volume, enthalpy, and structural relaxation decouple for changes in cooling rates and pressure of freezing, respectively. The magnitude of the divergence between enthalpy and volume may be related to differences in structural sensitivity to changes in the (p,V,T,t) space on different length scales. The findings suggest that the Prigogine-Defay ratio is related to the magnitude of the discussed decoupling effect.

Wondraczek, Lothar; Behrens, Harald

2007-10-01

69

Densities and excess molar volumes of Methanol, Ethanol and N-Propanol in pure Water and in Water + Surf Excel solutions at different temperatures  

Microsoft Academic Search

Densities, ? of the systems Methanol, Ethanol and n-Propanol in water and in 0.05 and 0.1% Surf Excel (SE) solutions in water were measured at temperatures from 303.15 to 323.15?K covering the whole composition range. Excess molar volumes, for the systems were found to be negative and large in magnitude. Densities and excess molar volumes have been plotted against mole

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

2004-01-01

70

Recurrent pregnancy loss in a woman with NLRP7 mutation: not all molar pregnancies can be easily classified as either "partial" or "complete" hydatidiform moles.  

PubMed

Recurrent hydatidiform moles is an uncommon occurrence. Over the past decade, genetic studies of women with multiple recurrent molar pregnancies have revealed that maternal mutations in two different genes, NLRP7 and C6orf221, result in recurrent moles. We report a 23 year old woman, born of unrelated parents, who has experienced three molar pregnancies in succession. Whilst the first pregnancy was classified as a complete hydatidiform mole, the second and third moles defied classification as complete or partial mole using conventional histology, p57 nuclear staining pattern and ploidy studies. Molecular and cytogenetic studies proved that all three molar pregnancies were diploid and biparental in origin. Gene sequencing analysis showed that the patient is homozygous for a previously described mutation in NLRP7. A SNP microarray ruled out the presence of deletion of the NLRP7 locus. This case draws attention to the fact that recurrent molar pregnancies may be the result of specific, identifiable gene mutations, even in patients from non-consanguineous backgrounds. When pathologists encounter patients with molar pregnancies that are diploid and p57 negative and yet have fetal elements such as nucleated red blood cells or immature fetal tissues, it should heighten their suspicion of a possible genetic basis and appropriate molecular genetic workup performed with counseling offered. PMID:23722513

Brown, Lucia; Mount, Sharon; Reddy, Ramesh; Slim, Rima; Wong, Cheung; Jobanputra, Vaidehi; Clifford, Patrick; Merrill, Laura; Brown, Stephen

2013-07-01

71

Simple program calculates partial liquid volumes in vessels  

SciTech Connect

This paper reports on a simple calculator program which solves problems of partial liquid volumes for a variety of storage and process vessels, including inclined cylindrical vessels and those with conical heads. Engineers in the oil refining and chemical industries are often confronted with the problem of estimating partial liquid volumes in storage tanks or process vessels. Cistern, the calculator program presented here, allows fast and accurate resolution of problems for a wide range of vessels without user intervention, other than inputting the problem data. Running the program requires no mathematical skills. Cistern is written for Hewlett-Packard HP 41CV or HP 41CX programmable calculators (or HP 41C with extended memory modules).

Koch, P.

1992-04-13

72

An MRI-guided PET partial volume correction method  

NASA Astrophysics Data System (ADS)

Accurate quantification of positron emission tomography (PET) is important for diagnosis and assessment of cancer treatment. The low spatial resolution of PET imaging induces partial volume effect to PET images that biases quantification. A PET partial volume correction method is proposed using high-resolution, anatomical information from magnetic resonance images (MRI). The corrected PET is pursued by removing the convolution of PET point spread function (PSF) and by preserving edges present in PET and the aligned MR images. The correction is implemented in a Bayesian's deconvolution framework that is minimized by a conjugate gradient method. The method is evaluated on simulated phantom and brain PET images. The results show that the method effectively restores 102 +/- 7% of the true PET activity with a size of greater than the full-width at half maximum of the point spread function. We also applied the method to synthesized brain PET data. The method does not require prior information about tracer activity within tissue regions. It can offer a partial volume correction method for various PET applications and can be particularly useful for combined PET/MRI studies.

Wang, Hesheng; Fei, Baowei

2009-02-01

73

Relation between heat of vaporization, ion transport, molar volume, and cation-anion binding energy for ionic liquids.  

PubMed

A number of correlations between heat of vaporization (H(vap)), cation-anion binding energy (E(+/-)), molar volume (V(m)), self-diffusion coefficient (D), and ionic conductivity for 29 ionic liquids have been investigated using molecular dynamics (MD) simulations that employed accurate and validated many-body polarizable force fields. A significant correlation between D and H(vap) has been found, while the best correlation was found for -log(DV(m)) vs H(vap) + 0.28E(+/-). A combination of enthalpy of vaporization and a fraction of the cation-anion binding energy was suggested as a measure of the effective cohesive energy for ionic liquids. A deviation of some ILs from the reported master curve is explained based upon ion packing and proposed diffusion pathways. No general correlations were found between the ion diffusion coefficient and molecular volume or the diffusion coefficient and cation/anion binding energy. PMID:19689161

Borodin, Oleg

2009-09-10

74

Densities and excess molar volumes of binary mixtures containing propylene carbonate + chlorohydrocarbons at 298.15 K and atmospheric pressure  

SciTech Connect

Densities and excess molar volumes, V{sub m}{sup E}, for binary mixtures containing propylene carbonate + 10 chlorohydrocarbons (dichloromethane, 1,2-dichloroethane, 1,3-dichloropropane, 1,4-dichlorobuthane, 1,6-dichlorohexane, 1,10-dichlorodecane, 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, trans-1,2-dichloroethene, and trichloroethene) have been measured at 298.15 K and at atmospheric pressure using an Anton Paar digital vibrating tube density meter. The results are fitted to the Redlich-Kister equation. The values of V{sub m}{sup E} for the mixtures containing dichloroalkanes show an increasing trend with the increase of the chain length and vary from a minimum of {minus}0.24 cm{sup 3}/mol for dichloromethane up to a maximum of +0.31 cm{sup 3}/mol for 1,10-dichlorodecane. The excess molar volumes for the other mixtures are negative over the entire range of composition. Results are qualitatively discussed in terms of molecular interactions.

Comelli, F. [Centro di Studio per la Fisica delle Macromolecule del CNR, Bologna (Italy); Francesconi, R. [Univ. degli Studi, Bologna (Italy). Dipt. di Chemica

1995-11-01

75

Anisotropic Partial Volume CSF Modeling for EEG Source Localization  

PubMed Central

Electromagnetic source localization (ESL) provides non-invasive evaluation of brain electrical activity for neurology research and clinical evaluation of neurological disorders such as epilepsy. Accurate ESL results are dependent upon the use of patient-specific models of bioelectric conductivity. While the effects of anisotropic conductivities in the skull and white matter have been previously studied, little attention has been paid to the accurate modeling of the highly conductive cerebrospinal fluid (CSF) region. This study examines the effect that partial volume errors in CSF segmentations have upon the ESL bioelectric model. These errors arise when segmenting sulcal channels whose widths are similar to the resolution of the magnetic resonance (MR) images used for segmentation, as some voxels containing both CSF and grey matter cannot be definitively assigned a single label. These problems, particularly prevalent in pediatric populations, make voxelwise segmentation of CSF compartments a difficult problem. Given the high conductivity of CSF, errors in modeling this region my result in large errors in the bioelectric model. We introduce here a new approach for using estimates of partial volume fractions in the construction of patient specific bioelectric models. In regions where partial volume errors are expected, we use a layered gray matter-CSF model to construct equivalent anisotropic conductivity tensors. This allows us to account for the inhomogeneity of the tissue within each voxel. Using this approach, we are able to reduce the error in the resulting bioelectric models, as evaluated against a known high resolution model. Additionally, this model permits us to evaluate the effects of sulci modeling errors and quantify the mean error as a function of the change in sulci width. Our results suggest that both under and over-estimation of the CSF region leads to significant errors in the bioelectric model. While a model with fixed partial volume fraction is able to reduce this error, we see the largest improvement when using voxel specific partial volume estimates. Our cross-model analyses suggest that an approximately linear relationship exists between sulci error and the error in the resulting bioelectric model. Given the difficulty of accurately segmenting narrow sulcal channels, this suggests that our approach may be capable of improving the accuracy of patient specific bioelectric models by several percent, while introducing only minimal additional computational requirements.

Hyde, Damon E.; Duffy, Frank H.; Warfield, Simon K.

2012-01-01

76

Anisotropic partial volume CSF modeling for EEG source localization.  

PubMed

Electromagnetic source localization (ESL) provides non-invasive evaluation of brain electrical activity for neurology research and clinical evaluation of neurological disorders such as epilepsy. Accurate ESL results are dependent upon the use of patient specific models of bioelectric conductivity. While the effects of anisotropic conductivities in the skull and white matter have been previously studied, little attention has been paid to the accurate modeling of the highly conductive cerebrospinal fluid (CSF) region. This study examines the effect that partial volume errors in CSF segmentations have upon the ESL bioelectric model. These errors arise when segmenting sulcal channels whose widths are similar to the resolution of the magnetic resonance (MR) images used for segmentation, as some voxels containing both CSF and gray matter cannot be definitively assigned a single label. These problems, particularly prevalent in pediatric populations, make voxelwise segmentation of CSF compartments a difficult problem. Given the high conductivity of CSF, errors in modeling this region may result in large errors in the bioelectric model. We introduce here a new approach for using estimates of partial volume fractions in the construction of patient specific bioelectric models. In regions where partial volume errors are expected, we use a layered gray matter-CSF model to construct equivalent anisotropic conductivity tensors. This allows us to account for the inhomogeneity of the tissue within each voxel. Using this approach, we are able to reduce the error in the resulting bioelectric models, as evaluated against a known high resolution model. Additionally, this model permits us to evaluate the effects of sulci modeling errors and quantify the mean error as a function of the change in sulci width. Our results suggest that both under and over-estimation of the CSF region leads to significant errors in the bioelectric model. While a model with fixed partial volume fraction is able to reduce this error, we see the largest improvement when using voxel specific partial volume estimates. Our cross-model analyses suggest that an approximately linear relationship exists between sulci error and the error in the resulting bioelectric model. Given the difficulty of accurately segmenting narrow sulcal channels, this suggests that our approach may be capable of improving the accuracy of patient specific bioelectric models by several percent, while introducing only minimal additional computational requirements. PMID:22652021

Hyde, Damon E; Duffy, Frank H; Warfield, Simon K

2012-05-29

77

Hydration of proteins: excess partial volumes of water and proteins.  

PubMed

High precision densitometry was applied to study the hydration of proteins. The hydration process was analyzed by the simultaneous monitoring of the excess partial volumes of water and the proteins in the entire range of water content. Five unrelated proteins (lysozyme, chymotrypsinogen A, ovalbumin, human serum albumin, and ?-lactoglobulin) were used as models. The obtained data were compared with the excess partial enthalpies of water and the proteins. It was shown that the excess partial quantities are very sensitive to the changes in the state of water and proteins. At the lowest water weight fractions (w(1)), the changes of the excess functions can mainly be attributed to water addition. A transition from the glassy to the flexible state of the proteins is accompanied by significant changes in the excess partial quantities of water and the proteins. This transition appears at a water weight fraction of 0.06 when charged groups of proteins are covered. Excess partial quantities reach their fully hydrated values at w(1) > 0.5 when coverage of both polar and weakly interacting surface elements is complete. At the highest water contents, water addition has no significant effect on the excess quantities. At w(1) > 0.5, changes in the excess functions can solely be attributed to changes in the state of the proteins. PMID:22380610

Sirotkin, Vladimir A; Komissarov, Igor A; Khadiullina, Aigul V

2012-03-22

78

Excess molar volumes and refractive indices at 298.15 K for the binary and ternary mixtures of diisopropyl ether + ethanol + 2,2,4-trimethylpentane  

Microsoft Academic Search

Excess molar volumes (VE) and deviations in molar refractivity (?R) data at 298.15K are reported for the binary systems diisopropyl ether+ethanol, diisopropyl ether+2,2,4-trimethylpentane(isooctane) and ethanol+isooctane and also for ternary systems of diisopropyl ether+ethanol+isooctane by digital vibrating tube densimeter and a precision digital refractometer. The VE and ?R were correlated with Redlich–Kister equation for binary systems and Cibulka equation for ternary

Se-Jin In; So-Jin Park

2008-01-01

79

Phase equilibria modelling applied to fluid inclusions: Liquid-vapour equilibria and calculation of the molar volume in the CO 2?CH 4?N 2 system  

NASA Astrophysics Data System (ADS)

Quantitative use of fluid inclusions requires the determination of composition and molar volume. The molar volume can be calculated in the CO 2?CH 4?N 2 system from both the determination of the temperature of a L + V ? L ( orV) equilibrium if the composition is known independently, provided an equation of state (EOS) reproduces the P- V- T- X properties of each phase at equilibrium. This study is applicable to fluids for which the sequence of phase transition is Sco2 + L + V ? L + V ? L ( orV) at increasing temperature. The molar volume is determined by following a two-step algorithm: (1) the pressure is calculated from a two-parameter cubic EOS with interaction parameters optimised along experimental L- V isotherms; (2) the molar volume is then calculated by the correlation of LEE and KESLER (1975) with the pressure calculated in the first step. Projections of polybaric L- V isotherms in v- x diagrams of the CO 2?CH 4, CO 2?N 2, and CH 4?N 2 systems can be directly applied to fluid inclusion studies. In addition, it is shown that the molar volume of CO 2-rich fluids ( Xco2 > 0.6) in the ternary system can be estimated with sufficient accuracy using empirical formulae relating to the v- x diagrams of the CO 2?CH 4 and CO 2?N 2 binary systems.

Thiery, R.; Vidal, J.; Dubessy, J.

1994-02-01

80

Volumetry of human molars with flat panel-based volume CT in vitro  

Microsoft Academic Search

The flat panel-based volume computed tomography (fpVCT) is a new CT device applicable for experimental, three-dimensional evaluation of teeth at a resolution of about 150 ?m in the high contrast region. The aim of this study was to investigate whether fpVCT was suitable for quantification of the volumes of dental hard tissues and the root canal system to establish a new

Christian Hannig; Eva Krieger; Christian Dullin; Hans-Albert Merten; Thomas Attin; Eckhardt Grabbe; Gabert Heidrich

2006-01-01

81

Excess molar volumes and viscosities of binary mixtures of 1,2-dimethoxyethane with chloroalkanes at 298·15 K  

Microsoft Academic Search

Excess molar volumes (V\\u000a \\u000a m\\u000a \\u000a \\u000a E\\u000a ), viscosity deviations (?ln?) and excess energies of activation for viscous flow (?G*E) are reported for non-electrolyte mixtures of 1,2-dimethoxyethane (monoglyme) and dichloromethane, trichloromethane, and\\u000a tetrachloromethane at 298·15 K and at atmospheric pressure over the whole mole fraction range. The Prigogine-Flory-Patterson\\u000a (PFP) model has been used to calculateV\\u000a \\u000a m\\u000a \\u000a \\u000a E\\u000a , and the results

Amalendu Pal; Gurcharan Dass; Sanjay Sharma

1999-01-01

82

Ventricle Boundary in CT: Partial Volume Effect and Local Thresholds  

PubMed Central

We present a mathematical frame to carry out segmentation of cerebrospinal fluid (CSF) of ventricular region in computed tomography (CT) images in the presence of partial volume effect (PVE). First, the image histogram is fitted using the Gaussian mixture model (GMM). Analyzing the GMM, we find global threshold based on parameters of distributions for CSF, and for the combined white and grey matter (WGM). The parameters of distribution of PVE pixels on the boundary of ventricles are estimated by using a convolution operator. These parameters are used to calculate local thresholds for boundary pixels by the analysis of contribution of the neighbor pixels intensities into a PVE pixel. The method works even in the case of an almost unimodal histogram; it can be useful to analyze the parameters of PVE in the ground truth provided by the expert.

Volkau, Ihar; Puspitasari, Fiftarina; Nowinski, Wieslaw L.

2010-01-01

83

Phenomenological partial-specific volumes for G-quadruplex DNAs.  

PubMed

Accurate partial-specific volume ([Formula: see text]) values are required for sedimentation velocity and sedimentation equilibrium analyses. For nucleic acids, the estimation of these values is complicated by the fact that [Formula: see text] depends on base composition, secondary structure, solvation and the concentrations and identities of ions in the surrounding buffer. Here we describe sedimentation equilibrium measurements of the apparent isopotential partial-specific volume /' for two G-quadruplex DNAs and a single-stranded DNA of similar molecular weight and base composition. The G-quadruplex DNAs are a 22 nucleotide fragment of the human telomere consensus sequence and a 27 nucleotide fragment from the human c-myc promoter. The single-stranded DNA is 26 nucleotides long and is designed to have low propensity to form secondary structures. Parallel measurements were made in buffers containing NaCl and in buffers containing KCl, spanning the range 0.09 M

Hellman, Lance M; Rodgers, David W; Fried, Michael Gregory

2009-02-24

84

Molar heat capacity at constant volume of difluoromethane (R32) and pentafluoroethane (R125) from the triple-point temperature to 345 K at pressures to 35 MPa  

Microsoft Academic Search

Molar heat capacities at constant volume (Cv) of dill uoromethane (R32) and pentalluoroethane (R125) were measured with an adiabatic calorimeter. Temperatures ranged from their triple points to 345 K, and pressures up to 35 MPa. Measurements were conducted on the liquid in equilibrium with its vapor and on compressed liquid samples. The samples were of a high purity, verified by

T. O. Lueddecke; J. W. Magee

1996-01-01

85

Molar heat capacity at constant volume of difluoromethane (R32) and pentafluoroethane (R125) from the triple-point temperature to 345 K at pressures to 35 MPa  

Microsoft Academic Search

Molar heat capacities at constant volume ( C v) of dill uoromethane (R32) and pentalluoroethane (R125) were measured with an adiabatic calorimeter. Temperatures ranged from their triple points to 345 K, and pressures up to 35 MPa. Measurements were conducted on the liquid in equilibrium with its vapor and on compressed liquid samples. The samples were of a high purity,

T. O. Lüddecke; J. W. Magee

1996-01-01

86

The molar volume of FeO-MgO-Fe2O3-Cr2O3-Al2O3-TiO2 spinels  

NASA Astrophysics Data System (ADS)

We define and calibrate a new model of molar volume as a function of pressure, temperature, ordering state, and composition for spinels in the supersystem (Mg, Fe2+)(Al, Cr, Fe3+)2O4 - (Mg, Fe2+)2TiO4. We use 832 X-ray and neutron diffraction measurements performed on spinels at ambient and in situ high- P, T conditions 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 allow 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 state of the various spinel end members are 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 preferred model has a total of 9 excess volume and order-dependent 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 spinel model with a demonstration of the impact of the model difference on the estimated spinel-garnet lherzolite transition pressure.

Hamecher, Emily A.; Antoshechkina, Paula M.; Ghiorso, Mark S.; Asimow, Paul D.

2013-01-01

87

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

88

Temperature Dependence of Densities and Excess Molar Volumes of the Ternary Mixture (1-Butanol + Chloroform + Benzene) and its Binary Constituents (1-Butanol + Chloroform and 1-Butanol + Benzene)  

NASA Astrophysics Data System (ADS)

Densities ? of the 1-butanol + chloroform + benzene ternary mixture and the 1-butanol + chloroform and 1-butanol + benzene binaries have been measured at six temperatures (288.15, 293.15, 298.15, 303.15, 308.15, and 313.15) K and atmospheric pressure, using an oscillating U-tube densimeter. From these densities, excess molar volumes ( V E) were calculated and fitted to the Redlich Kister equation for all binary mixtures and to the Nagata and Tamura equation for the ternary system. The Radojkovi? et al. equation has been used to predict excess molar volumes of the ternary mixtures. Also, V E data of the binary systems were correlated by the van der Waals (vdW1) and Twu Coon Bluck Tilton (TCBT) mixing rules coupled with the Peng Robinson Stryjek Vera (PRSV) equation of state. The prediction and correlation of V E data for the ternary system were performed by the same models.

Smiljani?, Jelena D.; Kijev?anin, Mirjana Lj.; Djordjevi?, Bojan D.; Grozdani?, Dušan K.; Šerbanovi?, Slobodan P.

2008-04-01

89

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

90

Excess molar volumes of an (1-alcohols+2,5-dioxahexane or 5,8,11-trioxapentadecane or 2-isopropoxyethanol) at 298.15 K  

Microsoft Academic Search

Excess molar volumes VE for binary liquid mixtures of an (1-alcohols+2,5-dioxahexane or 5,8,11-trioxapentadecane or 2-isopropoxy ethanol) have been measured as a function of compositions using a continuous-dilution dilatometer at 298.15 K and atmospheric pressure over the whole concentration range. The 1-alcohols were methanol, 1-propanol, and 1-pentanol. The VE for each of the mixtures studied are negative with the exception of

Amalendu Pal; Sanjay Sharma

1998-01-01

91

Apparent molar volumes and isentropic compressibilities of benzyltrialkylammonium chlorides in water at (293.15, 303.15, 313.15, 323.15, and 333.15) K  

Microsoft Academic Search

Densities and ultrasound speeds of benzyltrialkylammonium chlorides (BTAACls) were measured accurately in aqueous solutions at five temperatures (293.15, 303.15, 313.15, 323.15, and 333.15)K. The data were utilized in determining apparent molar volumes, V?, and apparent molar isentropic compressibilities, KS?. Infinite dilution values of these apparent molar quantities, V??andKS??, were determined by extrapolation procedures. Contribution of CH2 groups, along the alkyl

Osman Duman; Erol Ayranci

2009-01-01

92

Partial specific volume of poly(phenyl methacrylate)  

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.

93

Partial specific volume of poly(vinyl chloride)  

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.

94

Apparent molar volumes and heat capacities of aqueous acetic acid and sodium acetate at temperatures from T = 278.15 K to T = 393.15 K at the pressure 0.3 5 MPa  

Microsoft Academic Search

Apparent molar volumes V?and heat capacities Cp , ?of aqueous solutions of acetic acid (CH3CO2H) and sodium acetate (CH3CO2Na) , and Cp , ?for hydrochloric acid (HCl) and sodium hydroxide (NaOH) were determined at temperatures from T= 278.15 K to T= 393.15 K at the pressure 0.35MPa. Apparent molar volumes were obtained from density measurements using an Anton Paar vibrating-tube

K. Ballerat-Busserolles; T. D. Ford; T. G. Call; E. M. Woolley

1999-01-01

95

Determination of Pulmonary Parenchymal Tissue Volume and Pulmonary Capillary Blood Flow by a Partial Rebreathing Technique.  

National Technical Information Service (NTIS)

A new method is reported on measuring pulmonary tissue volume and pulmonary blood flow volume by means of partial rebreathing technique using a mass spectrometer. This technique is an altered method of Cander and others' technique, and according to the fo...

O. Nishida

1971-01-01

96

Molar heat capacity at constant volume of difluoromethane (R32) and pentafluoroethane (R125) from the triple-point temperature to 345 K at pressures to 35 MPa  

SciTech Connect

Molar heat capacities at constant volume (C{sub v}) of difluoromethane (R32) and pentafluoroethane (R125) were measured with an adiabatic calorimeter. Temperatures ranged from their triple points to 345 K, and pressures up to 35 MPa. Measurements were conducted on the liquid in equilibrium with its vapor and on compressed liquid samples. The samples were of a high purity, verified by chemical analysis of each fluid. For the samples, calorimetric results were obtained for two-phase (C{sub v}{sup (2)}), saturated liquid (C{sub {sigma}} or C {prime}{sub x}), and single-phase (C{sub v}) molar heat capacities. The C{sub {sigma}} data were used to estimate vapor pressures for values less than 0.3 MPa by applying a thermodynamic relationship between the saturated liquid heat capacity and the temperature derivatives of the vapor pressure. The triple-point temperature (T{sub tr}) and the enthalpy of fusion ({Delta}{sub fus}H) were also measured for each substance. The principal sources of uncertainty are the temperature rise measurement and the change-of-volume work adjustment. The expanded uncertainty (at the two-sigma level) for C{sub v} is estimated to be 0.7%, for C{sub v}{sup (2)} it is 0.5%, and for C{sub {sigma}} it is 0.7%.

Lueddecke, T.O.; Magee, J.W. [National Inst. of Standards and Technology, Boulder, CO (United States)

1996-07-01

97

Mass-action model analysis of the apparent molar volume and heat capacity of pluronics in water and liposome suspensions at 25 °C.  

PubMed

Pluronics are block copolymers composed of a central block of polypropylene oxide and two side chains of polyethylene oxide. They are used in water to generate aggregates and gels or added to phospholipid suspensions to prepare microparticles for drug delivery applications. The structure of these systems has been widely investigated. However, little is known about the mechanisms leading to these structures. This investigation compares the apparent molar volumes and heat capacities of Pluronics F38, F108, F127, P85, P104, and P103 at 25 °C in water and in the presence of lecithin liposomes. The changes in molar volumes, heat capacities, and enthalpies generated by a mass-action model are in good agreement with the loss of hydrophobic hydration of the polypropylene oxide central block of the Pluronics. However, the molecularity of the endothermic transitions is much smaller than the aggregation numbers reported in the literature for the same systems. It is suggested that Pluronics go through dehydration of their central block to form unimolecular or small entities having a hydrophobic polypropylene oxide core. In water, these entities would assemble athermally to form larger aggregates. In the presence of liposomes, they would be transferred into the hydrophobic lecithin bilayers of the liposomes. Light transmission experiments suggest that the liposome suspensions are significantly altered only when the added Pluronics are in the dehydrated state. PMID:23738755

Quirion, François; Meilleur, Luc; Lévesque, Isabelle

2013-06-24

98

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

99

Partial US oil, gas resource volumes termed astonishing'  

SciTech Connect

Land and state waters of the US contain technically recoverable volumes of 112.6 billion bbl of oil and 1,073.8 tcf of conventional and unconventional gas, the US Geological Survey estimated. The oil figure is 44% higher than the USGS assessed in its last study, released in 1989. The assessed 715 tcf of technically recoverable conventional gas reserves, expected reserve growth, and undiscovered accumulations is nearly 42% higher than the 1989 assessment. Moreover, the USGS for the first time assessed a further 300 tcf of technically recoverable gas in continuous-type largely unconventional deposits in sandstones, shales, and chalks, and almost another 50 tcf in coal beds. USGS estimated that 60 billion bbl will be added to the oil reserves and 322 tcf to the oil reserves and 322 tcf to the gas reserves of existing fields by way of revisions, extensions, and new pool discoveries during the 80 years following 1991. The estimates assume use of existing technology, and ignore barriers to leasing of onshore federal lands. The paper describes the results more fully.

Petzet, G.A.

1995-03-06

100

Molar heat capacity at constant volume of difluoromethane (R32) and pentafluoroethane (R125) from the triple-point temperature to 345 K at pressures to 35 MPa  

NASA Astrophysics Data System (ADS)

Molar heat capacities at constant volume ( C v) of dill uoromethane (R32) and pentalluoroethane (R125) were measured with an adiabatic calorimeter. Temperatures ranged from their triple points to 345 K, and pressures up to 35 MPa. Measurements were conducted on the liquid in equilibrium with its vapor and on compressed liquid samples. The samples were of a high purity, verified by chemical analysis of each fluid. For the samples, calorimetric results were obtained for two-phase ( C {v/(2)}), saturated liquid ( C ? or C' x ), and singlephase ( C v) molar heat capacities. The C ? data were used to estimate vapor pressures for values less than 0.3 MPa by applying a thermodynamic relationship between the saturated liquid heat capacity and the temperature derivatives of the vapor pressure. The triple-point temperature ( T tr) and the enthalpy of fusion (?fus H) were also measured for each substance. The principal sources of uncertainty are the temperature rise measurement and the change-ofvolume work adjustment. The expanded uncertainty (at the two-sigma level) for C v is estimated to be 0.7%, for C {v/(2)} it is 0.5%, and for C ? it is 0.7%.

Lüddecke, T. O.; Magee, J. W.

1996-07-01

101

Quantitative Magnetic Resonance Imaging Detects Changes in Meniscal Volume In Vivo After Partial Meniscectomy  

Microsoft Academic Search

Background: Quantifying changes in meniscal volume in vivo before and after partial meniscectomy (PM) could help elucidate the mechanisms involved in osteoarthritis development after meniscal injury and its surgical treatment.Purpose\\/Hypothesis: To determine whether quantitative magnetic resonance imaging (qMRI) can detect the immediate reduction in meniscal volume created by PM, while ruling out changes in unresected structures. We hypothesized that qMRI

Megan E. Bowers; Glenn A. Tung; Heidi L. Oksendahl; Michael J. Hulstyn; Paul D. Fadale; Jason T. Machan; Braden C. Fleming

2010-01-01

102

Damage and morbidity from pneumonitis after irradiation of partial volumes of mouse lung  

Microsoft Academic Search

Purpose: The aims of this study were to: (a) define the relationship of dose and volume irradiated to damage and morbidity in mouse lung; (b) determine the threshold volume for morbidity after partial lung irradiation; and (c) determine whether the response to radiation of mouse lung is independent of the region irradiated.Methods and Materials: C3Hf\\/Kam female mice were used in

Zhong-Xing Liao; Elizabeth L. Travis; Susan L. Tucker

1995-01-01

103

Partial volume effect-corrected FDG PET and grey matter volume loss in patients with mild Alzheimer’s disease  

Microsoft Academic Search

Purpose  Although 18F-fluorodeoxyglucose (FDG) PET is an established imaging technique to assess brain glucose utilisation, accurate measurement\\u000a of tracer concentration is confounded by the presence of partial volume effect (PVE) due to the limited spatial resolution\\u000a of PET, which is particularly true in atrophic brains such as those encountered in patients with Alzheimer’s disease (AD).\\u000a Our aim was to investigate the

Miharu Samuraki; Ichiro Matsunari; Wei-Ping Chen; Kazuyoshi Yajima; Daisuke Yanase; Akihiko Fujikawa; Nozomi Takeda; Shintaro Nishimura; Hiroshi Matsuda; Masahito Yamada

2007-01-01

104

The partial volume effect in PET\\/SPECT and Benford's Law  

Microsoft Academic Search

In this work we consider a probabilistic methodology that models the intensity distributions found in pure and partial volume (PV) voxels. We introduce some methodological developments that enable explicit modeling of the PV voxels prior probability density function (PDF). This new formulation can be applied generically across different imaging modalities including PET and SPECT. In this paper, we establish for

Kevin Wells; John Chiverton; Mike Partridge; Miriam Barry; Haval Kadhem; Bob Ott

2005-01-01

105

A multiresolution image based approach for correction of partial volume effects in emission tomography  

Microsoft Academic Search

Partial volume effects (PVEs) are consequences of the limited spatial resolution in emission tomography. They lead to a loss of signal in tissues of size similar to the point spread function and induce activity spillover between regions. Although PVE can be corrected for by using algorithms that provide the correct radioactivity concentration in a series of regions of interest (ROIs),

N. Boussion; M. Hatt; F. Lamare; Y. Bizais; A. Turzo; C. Cheze-LeRest; D. Visvikis

2006-01-01

106

Partial Volume Estimation of Brain Cortex from MRI Using Topology-Corrected Segmentation  

Microsoft Academic Search

In magnetic resonance imaging (MRI), accuracy of brain structures quantification may be affected by the partial volume (PV) effect. PV is due to the limited spatial resolution of MRI compared to the size of anatomical structures. When considering the cortex, measurements can be even more difficult as it spans only a few voxels. In tight sulci areas, where the two

Andrea Rueda; Oscar Acosta; Pierrick Bourgeat; Jurgen Fripp; Erik Bonner; Nicholas Dowson; Michel Couprie; Eduardo Romero; Olivier Salvado

2009-01-01

107

Anisotropic equivalent conductivity tensors for bioelectric modeling of partial volume effects in cerebrospinal fluid spaces  

Microsoft Academic Search

Accurate modeling of bioelectric propagation within the head is necessary for precise electromagnetic source localization. We present here a new approach for modeling spaces fractionally composed of grey matter and cerebrospinal fluid. Using information about the orientation of the cortical surface, we construct anisotropic conductivity tensors to model the partial volume effects frequently present within sulci. Our results indicate that

Damon E. Hyde; Simon K. Warfield

2011-01-01

108

Lesion quantification in oncological positron emission tomography: a maximum likelihood partial volume correction strategy.  

PubMed

A maximum likelihood (ML) partial volume effect correction (PVEC) strategy for the quantification of uptake and volume of oncological lesions in 18F-FDG positron emission tomography is proposed. The algorithm is based on the application of ML reconstruction on volumetric regional basis functions initially defined on a smooth standard clinical image and iteratively updated in terms of their activity and volume. The volume of interest (VOI) containing a previously detected region is segmented by a k-means algorithm in three regions: A central region surrounded by a partial volume region and a spill-out region. All volume outside the VOI (background with all other structures) is handled as a unique basis function and therefore "frozen" in the reconstruction process except for a gain coefficient. The coefficients of the regional basis functions are iteratively estimated with an attenuation-weighted ordered subset expectation maximization (AWOSEM) algorithm in which a 3D, anisotropic, space variant model of point spread function (PSF) is included for resolution recovery. The reconstruction-segmentation process is iterated until convergence; at each iteration, segmentation is performed on the reconstructed image blurred by the system PSF in order to update the partial volume and spill-out regions. The developed PVEC strategy was tested on sphere phantom studies with activity contrasts of 7.5 and 4 and compared to a conventional recovery coefficient method. Improved volume and activity estimates were obtained with low computational costs, thanks to blur recovery and to a better local approximation to ML convergence. PMID:19673203

De Bernardi, Elisabetta; Faggiano, Elena; Zito, Felicia; Gerundini, Paolo; Baselli, Giuseppe

2009-07-01

109

Apparent molar volumes and apparent molar heat capacities of Pr(NO3)3(aq), Gd(NO3)3(aq), Ho(NO3)3(aq), and Y(NO3)3(aq) at T = (288.15, 298.15, 313.15 and 328.15) K and p = 0.1 MPa  

SciTech Connect

Relative densities and relative massic heat capacities have been measured for acidified solutions (prepared at University of Lethbridge) of Y(NO{sub 3}){sub 3}(aq), Pr(NO{sub 3}){sub 3}(aq), and Gd(NO{sub 3}){sub 3}(aq) at T = (288.15, 298.15, 313.15, and 328.15) K and p = 0.1 MPa. In addition, relative densities and massic heat capacities have been measured at the same temperatures and pressure for Y(NO{sub 3}){sub 3}(aq) and Ho(NO{sub 3}){sub 3}(aq) solutions which were supplied from the Lawrence Livermore National Laboratory (LLNL) (n.b. measurements at T = 328.15 K for Ho(NO{sub 3}){sub 3}(aq) were not performed due to the limited volume of solution available). Apparent molar volumes and apparent molar heat capacities for the aqueous salt solutions have been calculated from the experimental apparent molar properties of the acidified salt solutions using Young's Rule whereas the apparent molar properties of the LLNL solutions were calculated directly from the measured densities and massic heat capacities. The two sets of data for the Y(NO{sub 3}){sub 3}(aq) systems provide a check of the internal consistency of the Young's Rule approach we have utilized. The concentration dependences of the apparent molar volumes and heat capacities of the aqueous salt solutions have been modeled at each investigated temperature using the Pitzer ion interaction equations to yield apparent molar properties at infinite dilution. Complex formation within the aqueous rare earth nitrate systems is discussed and is qualitatively explored by probing the concentration dependence of apparent molar volumes and heat capacities. It is also shown that in spite of the complex formation within the aqueous rare earth nitrate systems there remains a high degree of self-consistency between the apparent molar volumes and heat capacities at infinite dilution reported in this manuscript and those previously reported for aqueous rare earth perchlorate salt systems.

Rard, J; Lui, J; Erickson, K; Munoz, J; Hakin, A H

2004-07-13

110

Quantitative Magnetic Resonance Imaging Detects Changes in Meniscal Volume in Vivo After Partial Meniscectomy  

PubMed Central

Background Quantifying changes in meniscal volume in vivo before and after partial meniscectomy (PM) could help elucidate the mechanisms involved in osteoarthritis development after meniscal injury and its surgical treatment. Purpose/Hypothesis To determine whether quantitative MRI (qMRI) could detect the immediate reduction in meniscal volume created by PM, while ruling out changes in unresected structures. We hypothesized that qMRI would be reliable for determining meniscal volume within the repeated images of unresected menisci. Additionally, we expected no significant difference in volume between the uninjured menisci of the injured knees and the same menisci of the uninjured knees. Study Design Controlled laboratory study. Methods Ten subjects with meniscal tears were evaluated with 3T MRI before and after arthroscopic PM. Manual segmentation was used to create models of the menisci and to determine the pre- and post-operative meniscal volumes for each subject. The responsiveness and reliability of qMRI for determining meniscal volume in vivo were evaluated using these measurements. We expected a decrease in volume of the resected menisci, but not in the uninjured menisci, after surgery. Results The mean pre-operative volume of the injured menisci was significantly greater than the mean post-operative volume (2896±277mm3 vs. 2480±277mm3; p=0.000). There was no significant difference between the mean pre- and post-operative volumes of the uninjured menisci (2687±256mm3 vs. 2694±256mm3; p=1.000). Conclusions Manual segmentation demonstrated a significant reduction in the volume of the surgically resected menisci after PM, but no significant change in the volume of unresected meniscal tissue, indicating that the manual segmentation method is responsive. Clinical Relevance This approach offers a novel, reliable method to study the relationship between the volume of meniscal tissue removed during PM and subsequent patient outcomes during long-term clinical studies.

Bowers, Megan E.; Tung, Glenn A.; Oksendahl, Heidi L.; Hulstyn, Michael J.; Fadale, Paul D.; Machan, Jason T.; Fleming, Braden C.

2010-01-01

111

Isotope effects in condensed phases, the benzene example. Influence of anharmonicity; harmonic and anharmonic potential surfaces and their isotope independence. Molar volume effects in isotopic benzenes  

SciTech Connect

Application of the harmonic oscillator cell model (HOCM) for condensed phase isotope effects to the benzene/deuterobenzene system using temperature dependent force fields, which yield good calculated values for vapor pressure isotope effects (VPIE) and reasonable agreement with spectroscopically observed frequency shifts on condensation, gives calculated values of isotope effect on energies of vaporization which are not in agreement with experiment. Pseudoharmonic corrections are inadequate to restore agreement with experiment. The VPIE in benzene is dominated by the contributions of the CH/CD stretching vibrations and consistency is achieved by expanding the model to include anharmonic corrections for these frequencies. In this fashion a combination of thermodynamic measurements of free energies (by vapor pressure) and energies (from the temperature coefficient of the vapor pressure or from calorimetry) can be employed to yield shifts in anharmonic vibrational constants on condensation. In the second part of the paper the molar volume isotope effect (MVIE) and the effects of volume, pressure, and temperature on the internal energy and its isotope effects (as monitored by the expansivity, compressibility, heat capacity, and their derivatives) are interpreted. The low-lying lattice modes make important contributions to these properties.

Van Hook, W.A.

1985-10-15

112

Comparison of EM-based and level set partial volume segmentations of MR brain images  

NASA Astrophysics Data System (ADS)

EM and level set algorithms are competing methods for segmenting MRI brain images. This paper presents a fair comparison of the two techniques using the Montreal Neurological Institute's software phantom. There are many flavors of level set algorithms for segmentation into multiple regions (multi-phase algorithms, multi-layer algorithms). The specific algorithm evaluated by us is a variant of the multi-layer level set algorithm. It uses a single level set function for segmenting the image into multiple classes and can be run to completion without restarting. The EM-based algorithm is standard. Both algorithms have the capacity to model a variable number of partial volume classes as well as image inhomogeneity (bias field). Our evaluation consists of systematically changing the number of partial volume classes, additive image noise, and regularization parameters. The results suggest that the performances of both algorithms are comparable across noise, number of partial volume classes, and regularization. The segmentation errors of both algorithms are around 5 - 10% for cerebrospinal fluid, gray and white matter. The level set algorithm appears to have a slight advantage for gray matter segmentation. This may be beneficial in studying certain brain diseases (Multiple Sclerosis or Alzheimer's disease) where small changes in gray matter volume are significant.

Tagare, Hemant D.; Chen, Yunmei; Fulbright, Robert K.

2008-04-01

113

Partial volume segmentation in 3D of lesions and tissues in magnetic resonance images  

NASA Astrophysics Data System (ADS)

An important first step in diagnosis and treatment planning using tomographic imaging is differentiating and quantifying diseased as well as healthy tissue. One of the difficulties encountered in solving this problem to date has been distinguishing the partial volume constituents of each voxel in the image volume. Most proposed solutions to this problem involve analysis of planar images, in sequence, in two dimensions only. We have extended a model-based method of image segmentation which applies the technique of iterated conditional modes in three dimensions. A minimum of user intervention is required to train the algorithm. Partial volume estimates for each voxel in the image are obtained yielding fractional compositions of multiple tissue types for individual voxels. A multispectral approach is applied, where spatially registered data sets are available. The algorithm is simple and has been parallelized using a dataflow programming environment to reduce the computational burden. The algorithm has been used to segment dual echo MRI data sets of multiple sclerosis patients using lesions, gray matter, white matter, and cerebrospinal fluid as the partial volume constituents. The results of the application of the algorithm to these datasets is presented and compared to the manual lesion segmentation of the same data.

Johnston, Brian; Atkins, M. Stella; Booth, Kellogg S.

1994-05-01

114

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

115

Comparative study of partial volume correction methods in small animal positron emission tomography (PET) of the rat brain  

Microsoft Academic Search

Quantitative accuracy in rat brain PET studies is reduced by partial volume effect. We investigated the performance of partial volume correction (PVC) in a realistic situation where activity is also taken up in the head and spills into the brain. The PVC approaches studied include the region-based geometric transfer matrix (GTM) method and voxel-based iterative deconvolution (reblurred Van Cittert and

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

2011-01-01

116

Densities and Excess Molar Volumes of Binary and Ternary Mixtures of Aqueous Solutions of 2,2,2-Trifluoroethanol with Acetone and Alcohols at the Temperature of 298.15 K and Pressure of 101 kPa  

Microsoft Academic Search

Excess molar volumes VmE of the binary mixtures of (trifluoroethanol + 1-propanol), (trifluoroethanol + 2-propanol), (acetone + water), (methanol + water), (ethanol + water), (1-propanol + water), (2-propanol + water), and the ternary mixtures of (trifluoroethanol + methanol + water), (trifluoroethanol + ethanol + water), (trifluoroethanol~+ 1-propanol + water), (trifluoroethanol + 2-propanol + water) and (trifluoroethanol + acetone + water)

Zadjia Atik

2004-01-01

117

Thermodynamics of mixtures with strongly negative deviations from Raoult’s law. Part 8. Excess molar volumes at 298.15 K for 1-alkanol + isomeric amine (C 6H 15N) systems  

Microsoft Academic Search

Excess molar volumes, VE, at 298.15K and atmospheric pressure, over the entire composition range for binary mixtures of methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol and 1-octanol with hexylamine (HxA) and of 1-propanol, 1-pentanol, 1-hexanol, 1-heptanol and 1-octanol with triethylamine (TEA) are reported. They are calculated from densities measured with a vibrating-tube densimeter. All the excess volumes are large and

S Villa; N Riesco; I Garc??a de la Fuente; J. A González; J. C Cobos

2004-01-01

118

Large-Volume Laparoscopic Partial Nephrectomy Using the Potassium-Titanyl-Phosphate (KTP) Laser in a Survival Porcine Model  

Microsoft Academic Search

ObjectivesLaparoscopic partial nephrectomy (LPN) remains a technically challenging procedure primarily because of difficulties with hemostasis. In an attempt to develop a hemostatic cutting instrument for laparoscopic partial nephrectomy, we evaluated the potassium-titanyl-phosphate (KTP) laser for use during large-volume laparoscopic partial nephrectomy in a porcine model.

J. Kyle Anderson; Meredith R. Baker; Guy Lindberg; Jeffrey A. Cadeddu

2007-01-01

119

Relationship Between Partial Gastric Volumes and Dyspeptic Symptoms in Fundoplication Patients: A 3D Ultrasonographic Study  

Microsoft Academic Search

OBJECTIVES:Impaired gastric accommodation may induce dyspeptic symptoms in postfundoplication patients. Our aim was to assess the effect of a meal on total and partial gastric volumes in relation to dyspeptic symptoms in both dyspeptic and nondyspeptic fundoplication patients using three-dimensional (3D) ultrasonography.METHODS:Eighteen postfundoplication patients of whom eight with and ten without dyspeptic symptoms and eighteen controls were studied. Three-dimensional ultrasonographic

R. C. H. Scheffer; H. G. Gooszen; E. B. Wassenaar; M. Samsom

2004-01-01

120

Can partial volume effects be used to measure myocardial thickness and thickening?  

Microsoft Academic Search

It has been hypothesized that myocardial thickness and thickening can be measured from gated positron emission tomography (PET) or single-photon-emission computed tomography (SPECT) studies by observing the partial volume related intensity changes in the myocardium that occur from end-diastole to end-systole. The authors make a preliminary assessment of whether this hypothesis is valid. Using magnetic resonance imaging (MRI) data to

D. Y. Mok; M. L. Bartlett; S. L. Bacharach; L. M. Voipio-Pulkki; R. E. Carson; M. J. Domanski; V. Dilsizian; P. Perrone-Filardi; P. O. Bonow

1992-01-01

121

Paradoxical response to nebulised salbutamol in wheezy infants, assessed by partial expiratory flow-volume curves  

Microsoft Academic Search

Lower airway responses to nebulised bronchodilators were studied in 18 chronically or recurrently wheezy infants, aged 3-15 months, by means of partial forced expiratory flow-volume manoeuvres performed with an inflatable jacket. Maximum flow at functional residual capacity (FRC) (VmaxFRC) was used as the index of intrathoracic airways function. Peak expiratory flow rate was also measured. Baseline airways resistance and lung

A Prendiville; S Green; M Silverman

1987-01-01

122

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

123

Attachment Levels and Crevicular Depths at the Distal of Mandibular Second Molars Following Removal of Adjacent Third Molars.  

National Technical Information Service (NTIS)

The effect of root planing and curettage on the crevicular depth and periodontal attachment at the distal of mandibular second molars following removal of adjacent impacted or partially erupted third molars was evaluated in eighteen patients between the a...

W. H. Osborne A. J. Snyder T. R. Tempel

1981-01-01

124

Alzheimer's disease detection using 11C-PiB with improved partial volume effect correction  

NASA Astrophysics Data System (ADS)

Despite the increasing use of 11C-PiB in research into Alzheimer's disease (AD), there are few standardized analysis procedures that have been reported or published. This is especially true with regards to partial volume effects (PVE) and partial volume correction. Due to the nature of PET physics and acquisition, PET images exhibit relatively low spatial resolution compared to other modalities, resulting in bias of quantitative results. Although previous studies have applied PVE correction techniques on 11C-PiB data, the results have not been quantitatively evaluated and compared against uncorrected data. The aim of this study is threefold. Firstly, a realistic synthetic phantom was created to quantify PVE. Secondly, MRI partial volume estimate segmentations were used to improve voxel-based PVE correction instead of using hard segmentations. Thirdly, quantification of PVE correction was evaluated on 34 subjects (AD=10, Normal Controls (NC)=24), including 12 PiB positive NC. Regional analysis was performed using the Anatomical Automatic Labeling (AAL) template, which was registered to each patient. Regions of interest were restricted to the gray matter (GM) defined by the MR segmentation. Average normalized intensity of the neocortex and selected regions were used to evaluate the discrimination power between AD and NC both with and without PVE correction. Receiver Operating Characteristic (ROC) curves were computed for the binary discrimination task. The phantom study revealed signal losses due to PVE between 10 to 40 % which were mostly recovered to within 5% after correction. Better classification was achieved after PVE correction, resulting in higher areas under ROC curves.

Raniga, Parnesh; Bourgeat, Pierrick; Fripp, Jurgen; Acosta, Oscar; Ourselin, Sebastien; Rowe, Christopher; Villemagne, Victor L.; Salvado, Olivier

2009-02-01

125

A Partial Volume Effect Correction Tailored for 18F-FDG-PET Oncological Studies  

PubMed Central

We have developed, optimized, and validated a method for partial volume effect (PVE) correction of oncological lesions in positron emission tomography (PET) clinical studies, based on recovery coefficients (RC) and on PET measurements of lesion-to-background ratio (L/Bm) and of lesion metabolic volume. An operator-independent technique, based on an optimised threshold of the maximum lesion uptake, allows to define an isocontour around the lesion on PET images in order to measure both lesion radioactivity uptake and lesion metabolic volume. RC are experimentally derived from PET measurements of hot spheres in hot background, miming oncological lesions. RC were obtained as a function of PET measured sphere-to-background ratio and PET measured sphere metabolic volume, both resulting from the threshold-isocontour technique. PVE correction of lesions of a diameter ranging from 10?mm to 40?mm and for measured L/Bm from 2 to 30 was performed using measured RC curves tailored at answering the need to quantify a large variety of real oncological lesions by means of PET. Validation of the PVE correction method resulted to be accurate (>89%) in clinical realistic conditions for lesion diameter > 1?cm, recovering >76% of radioactivity for lesion diameter < 1?cm. Results from patient studies showed that the proposed PVE correction method is suitable and feasible and has an impact on a clinical environment.

Gallivanone, F.; Canevari, C.; Gianolli, L.; Salvatore, C.; Della Rosa, P. A.; Gilardi, M. C.; Castiglioni, I.

2013-01-01

126

Molar Heat Capacity at Constant Volume of 1,1-Difluoroethane (R152a) and 1,1,1-Trifluoroethane (R143a) from the Triple-Point Temperature to 345 K at Pressures to 35 MPa  

Microsoft Academic Search

Molar heat capacities at constant volume (Cv) of 1,1-difluoroethane (R152a) and 1,1,1-trifluoroethane (R143a) have been measured with an adiabatic calorimeter. Temperatures ranged from their triple points to 345 K, and pressures up to 35 MPa. Measurements were conducted on the liquid in equilibrium with its vapor and on compressed liquid samples. The samples were of high purity, verified by chemical

J. W. Magee

1998-01-01

127

Molar heat capacity at constant volume of 1,1-difluoroethane (R152a) and 1,1,1-trifluoroethane (R143a) from the triple-point temperature to 345 k at pressure to 35 MPa  

Microsoft Academic Search

Molar heat capacities at constant volume (C{sub v}) of 1,1-difluoroethane (R152a) and 1,1,1-trifluoroethane (R143a) have been measured with an adiabatic calorimeter. Temperatures ranged from their triple points to 345 K, and pressures up to 35 MPa. Measurements were conducted on the liquid in equilibrium with its vapor and on compressed liquid samples. The samples were of high purity, verified by

Magee

1998-01-01

128

Excess molar volume, viscosity, and refractive index study for the ternary mixture {2-methyl-2-butanol (1) + tetrahydrofuran (2) + propylamine (3)} at different temperatures. Application of the ERAS-model and Peng–Robinson–Stryjek–Vera equation of state  

Microsoft Academic Search

Densities, viscosities, and refractive indices of the ternary mixture consist of {2-methyl-2-butanol (1)+tetrahydrofuran (THF) (2)+propylamine (3)} at a temperature of 298.15K and related binary mixtures were measured at temperatures of (288.15, 298.15, and 308.15)K at ambient pressure. Data were used to calculate the excess molar volumes and the deviations of the viscosity and refractive index. The Redlich–Kister and the Cibulka

M. Fattahi; H. Iloukhani

2010-01-01

129

The demographics of molar pregnancies in BPKIHS.  

PubMed

This is an analysis of the incidence of molar pregnancies and those of complete and partial molar pregnancies across the reproductive age range for BP Koirala Institute of Health Sciences (BPKIHS) in the period 2010-2011. Patients with molar pregnancies registered with BPKIHS from January 2008 to January 2010 were identified. The overall number of molar pregnancies registered was compared to the number of maternities (live births and still births) and total viable conceptions for this year. A retrospective study of 64 cases of molar pregnancies recorded at BPKIHS during the two year time was done. Medical records were reviewed. Incidence, clinical presentation and methods of diagnosis were studied. During the study period, there were 37 complete moles, 23 partial moles, 1 persistent gestational trophoblastic tumor, 1 choriocarcinoma, and 2 invasive moles. The incidence of molar pregnancy was 3.94 per 1000 deliveries. Median distribution was at 22 years of age, and majority (67%) presented during early second trimester. Twenty one (32.8%) women were of blood group A positive and ten (15.6%) presented with severe form of anemia. This study provides detailed data regarding the incidence of partial and complete molar pregnancies with increasing maternal age. It confirms the relation of molar pregnancy with age, and blood group. Complete mole had the highest incidence, affecting mostly younger age group, and usually in the first half of their pregnancy. PMID:22710543

Koirala, A; Khatiwada, P; Giri, A; Kandel, P; Regmi, M; Upreti, D

130

Morphological segmentation and partial volume analysis for volumetry of solid pulmonary lesions in thoracic CT scans.  

PubMed

Volumetric growth assessment of pulmonary lesions is crucial to both lung cancer screening and oncological therapy monitoring. While several methods for small pulmonary nodules have previously been presented, the segmentation of larger tumors that appear frequently in oncological patients and are more likely to be complexly interconnected with lung morphology has not yet received much attention. We present a fast, automated segmentation method that is based on morphological processing and is suitable for both small and large lesions. In addition, the proposed approach addresses clinical challenges to volume assessment such as variations in imaging protocol or inspiration state by introducing a method of segmentation-based partial volume analysis (SPVA) that follows on the segmentation procedure. Accuracy and reproducibility studies were performed to evaluate the new algorithms. In vivo interobserver and interscan studies on low-dose data from eight clinical metastasis patients revealed that clinically significant volume change can be detected reliably and with negligible computation time by the presented methods. In addition, phantom studies were conducted. Based on the segmentation performed with the proposed method, the performance of the SPVA volumetry method was compared with the conventional technique on a phantom that was scanned with different dosages and reconstructed with varying parameters. Both systematic and absolute errors were shown to be reduced substantially by the SPVA method. The method was especially successful in accounting for slice thickness and reconstruction kernel variations, where the median error was more than halved in comparison to the conventional approach. PMID:16608058

Kuhnigk, Jan-Martin; Dicken, Volker; Bornemann, Lars; Bakai, Annemarie; Wormanns, Dag; Krass, Stefan; Peitgen, Heinz-Otto

2006-04-01

131

Evaluation of NO2 predictions by the plume volume molar ratio method (PVMRM) and ozone limiting method (OLM) in AERMOD using new field observations.  

PubMed

The U.S. Environmental Protection Agency (EPA) plume volume molar ratio method (PVMRM) and the ozone limiting method (OLM) are in the AERMOD model to predict the 1-hr average NO2/NO(x) concentration ratio. These ratios are multiplied by the AERMOD predicted NO(x) concentration to predict the 1-hr average NO2 concentration. This paper first briefly reviews PVMRM and OLM and points out some scientific parameterizations that could be improved (such as specification of relative dispersion coefficients) and then discusses an evaluation of the PVMRM and OLM methods as implemented in AERMOD using a new data set. While AERMOD has undergone many model evaluation studies in its default mode, PVMRM and OLM are nondefault options, and to date only three NO2 field data sets have been used in their evaluations. Here AERMOD/PVMRM and AERMOD/OLM codes are evaluated with a new data set from a northern Alaskan village with a small power plant. Hourly pollutant concentrations (NO, NO2, ozone) as well as meteorological variables were measured at a single monitor 500 m from the plant. Power plant operating parameters and emissions were calculated based on hourly operator logs. Hourly observations covering 1 yr were considered, but the evaluations only used hours when the wind was in a 60 degrees sector including the monitor and when concentrations were above a threshold. PVMRM is found to have little bias in predictions of the C(NO2)/C(NO(x)) ratio, which mostly ranged from 0.2 to 0.4 at this site. OLM overpredicted the ratio. AERMOD overpredicts the maximum NO(x) concentration but has an underprediction bias for lower concentrations. AERMOD/PVMRM overpredicts the maximum C(NO2) by about 50%, while AERMOD/OLM overpredicts by a factor of 2. For 381 hours evaluated, there is a relative mean bias in C(NO2) predictions of near zero for AERMOD/PVMRM, while the relative mean bias reflects a factor of 2 overprediction for AERMOD/OLM. Implications: This study was initiated because the new stringent 1-hr NO2 NAAQS has prompted modelers to more widely use the PVMRM and OLM methods for conversion of NO(x) to NO2 in the AERMOD regulatory model. To date these methods have been evaluated with a limited number of data sets. This study identified a new data set of ambient pollutant and meteorological monitoring near an isolated power plant in Wainwright, Alaska. To supplement the existing evaluations, this new data were used to evaluate PVMRM and OLM. This new data set has been and will be made available to other scientists for future investigations. PMID:23926853

Hendrick, Elizabeth M; Tino, Vincent R; Hanna, Steven R; Egan, Bruce A

2013-07-01

132

Improved Regional Activity Quantitation in Nuclear Medicine Using a New Approach to Correct for Tissue Partial Volume and Spillover Effects  

Microsoft Academic Search

We have developed a new method of compensating for effects of partial volume and spillover in dual-modality imaging. The approach requires segmentation of just a few tissue types within a small volume-of-interest (VOI) surrounding a lesion; the algorithm estimates simultaneously, from projection data, the activity concentration within each segmented tissue inside the VOI. Measured emission projections were fitted to the

Stephen C. Moore; Sudeepti Southekal; Mi-Ae Park; Sarah J. McQuaid; Marie Foley Kijewski; Stefan P. Muller

2012-01-01

133

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

2013-06-27

134

A multiresolution image based approach for correction of partial volume effects in emission tomography  

NASA Astrophysics Data System (ADS)

Partial volume effects (PVEs) are consequences of the limited spatial resolution in emission tomography. They lead to a loss of signal in tissues of size similar to the point spread function and induce activity spillover between regions. Although PVE can be corrected for by using algorithms that provide the correct radioactivity concentration in a series of regions of interest (ROIs), so far little attention has been given to the possibility of creating improved images as a result of PVE correction. Potential advantages of PVE-corrected images include the ability to accurately delineate functional volumes as well as improving tumour-to-background ratio, resulting in an associated improvement in the analysis of response to therapy studies and diagnostic examinations, respectively. The objective of our study was therefore to develop a methodology for PVE correction not only to enable the accurate recuperation of activity concentrations, but also to generate PVE-corrected images. In the multiresolution analysis that we define here, details of a high-resolution image H (MRI or CT) are extracted, transformed and integrated in a low-resolution image L (PET or SPECT). A discrete wavelet transform of both H and L images is performed by using the 'à trous' algorithm, which allows the spatial frequencies (details, edges, textures) to be obtained easily at a level of resolution common to H and L. A model is then inferred to build the lacking details of L from the high-frequency details in H. The process was successfully tested on synthetic and simulated data, proving the ability to obtain accurately corrected images. Quantitative PVE correction was found to be comparable with a method considered as a reference but limited to ROI analyses. Visual improvement and quantitative correction were also obtained in two examples of clinical images, the first using a combined PET/CT scanner with a lymphoma patient and the second using a FDG brain PET and corresponding T1-weighted MRI in an epileptic patient.

Boussion, N.; Hatt, M.; Lamare, F.; Bizais, Y.; Turzo, A.; Cheze-LeRest, C.; Visvikis, D.

2006-04-01

135

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

136

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

PubMed Central

Purpose This study was performed to determine the spinal cord tolerance to single-fraction, partial-volume irradiation in swine. Methods/Materials A 5 cm long cervical segment was irradiated in 38-47 week old Yucatan minipigs using a dedicated, image-guided radiosurgery linear accelerator. 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. Dose was prescribed to the 90% isodose line. Twenty-six pigs were stratified into 8 dose groups from 12-47 Gy. The mean maximum spinal cord doses were 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 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 one year follow-up period. Results A steep dose response curve was observed with an ED50 (95% CI) for the maximum dose point of 20.0 Gy (18.3-21.7). Excellent agreement was observed between the occurrence of neurologic change and the presence of histological change. All animals with motor deficits showed some degree of demyelination and focal white matter necrosis on the irradiated side with relative sparing of the gray matter while histology was unremarkable in animals with normal neurologic status. Conclusions Results indicate that for a dose distribution with a steep lateral gradient, pigs have a lower ED50 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; Foster, Ryan D; van der Kogel, Albert J; Sayre, James W; McBride, William H; Solberg, Timothy D

2010-01-01

137

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

138

Two methods to generate templates for template-based partial volume effect correction: SPECT phantom experiments  

NASA Astrophysics Data System (ADS)

In this paper, we explore the applicability of template-based compensation for the partial volume effect (PVE) for situations where (i) the image has multiple uptake sites (tumors and organs) but only one of them is treated as a region of interest (ROI) with the boundaries available from a high-resolution modality and (ii) no information regarding activities inside or outside this ROI is a priori available. We modeled this situation by performing SPECT acquisitions of phantoms containing 21 containers, which had different shapes and sizes and were filled with different levels of activity. In our analysis, each of these containers was treated as an individual ROI. We compared the performance of two methods of template construction. In method 1, the ROI template value was obtained from a conventionally reconstructed (without PVEC) image. In method 2, the ROI template value was directly (bypassing the PVE-affected conventional image) calculated from projections using region-based reconstruction. Our processing shows that method 1 resulted in consistent (activities for all 21 ROIs were improved) but relatively weak PVE compensation (errors of recovered total activities were equal to or lower than 10% for 5 ROIs only). Application of method 2 resulted in a selective (activities for 19 ROIs were improved) but considerably better compensation when compared to method 1 (errors of recovered total activities were equal to or lower than 10% for 10 ROIs).

Shcherbinin, S.; Grimes, J.; Celler, A.

2013-02-01

139

Bi-exponential magnetic resonance signal model for partial volume computation.  

PubMed

Accurate quantification of small structures in magnetic resonance (MR) images is often limited by partial volume (PV) effects which arise when more than one tissue type is present in a voxel. PV may be critical when dealing with changes in brain anatomy as the considered structures such as gray matter (GM) are of similar size as the MR spatial resolution. To overcome the limitations imposed by PV effects and achieve subvoxel accuracy different methods have been proposed. Here, we describe a method to compute PV by modeling the MR signal with a biexponential linear combination representing the contribution of at most two tissues in each voxel. In a first step, we estimated the parameters (T1, T2 and proton density) per tissue. Then, based on the bi-exponential formulation one can retrieve fractional contents by solving a linear system of two equations with two unknowns, namely tissue magnetizations. Preliminary tests were conducted on images acquired on a specially designed physical phantom for the study of PV effects. Further, the model was tested on BrainWeb simulated brain images to estimate GM and white matter (WM) PV effects. Root mean squared error was computed between the BrainWeb ground truth and the obtained GM and WM PV maps. The proposed method outperformed traditionally used methods by 33% and 34% in GM and WM, respectively. PMID:23285556

Duché, Quentin; Acosta, Oscar; Gambarota, Giulio; Merlet, Isabelle; Salvado, Olivier; Saint-Jalmes, Hervé

2012-01-01

140

Partial volume effect estimation and correction in the aortic vascular wall in PET imaging.  

PubMed

We evaluated the impact of partial volume effect (PVE) in the assessment of arterial diseases with (18)FDG PET. An anthropomorphic digital phantom enabling the modeling of aorta related diseases like atherosclerosis and arteritis was used. Based on this phantom, we performed GATE Monte Carlo simulations to produce realistic PET images with a known organ segmentation and ground truth activity values. Images corresponding to 15 different activity-concentration ratios between the aortic wall and the blood and to 7 different wall thicknesses were generated. Using the PET images, we compared the theoretical wall-to-blood activity-concentration ratios (WBRs) with the measured WBRs obtained with five measurement methods: (1) measurement made by a physician (Expert), (2) automated measurement supposed to mimic the physician measurements (Max), (3) simple correction based on a recovery coefficient (Max-RC), (4) measurement based on an ideal VOI segmentation (Mean-VOI) and (5) measurement corrected for PVE using an ideal geometric transfer matrix (GTM) method. We found that Mean-VOI WBRs values were strongly affected by PVE. WBRs obtained by the physician measurement, by the Max method and by the Max-RC method were more accurate than WBRs obtained with the Mean-VOI approach. However Expert, Max and Max-RC WBRs strongly depended on the wall thickness. Only the GTM corrected WBRs did not depend on the wall thickness. Using the GTM method, we obtained more reproducible ratio values that could be compared across wall thickness. Yet, the feasibility of the implementation of a GTM-like method on real data remains to be studied. PMID:24099932

Burg, S; Dupas, A; Stute, S; Dieudonné, A; Huet, P; Le Guludec, D; Buvat, I

2013-10-08

141

Partial volume effect estimation and correction in the aortic vascular wall in PET imaging  

NASA Astrophysics Data System (ADS)

We evaluated the impact of partial volume effect (PVE) in the assessment of arterial diseases with 18FDG PET. An anthropomorphic digital phantom enabling the modeling of aorta related diseases like atherosclerosis and arteritis was used. Based on this phantom, we performed GATE Monte Carlo simulations to produce realistic PET images with a known organ segmentation and ground truth activity values. Images corresponding to 15 different activity-concentration ratios between the aortic wall and the blood and to 7 different wall thicknesses were generated. Using the PET images, we compared the theoretical wall-to-blood activity-concentration ratios (WBRs) with the measured WBRs obtained with five measurement methods: (1) measurement made by a physician (Expert), (2) automated measurement supposed to mimic the physician measurements (Max), (3) simple correction based on a recovery coefficient (Max-RC), (4) measurement based on an ideal VOI segmentation (Mean-VOI) and (5) measurement corrected for PVE using an ideal geometric transfer matrix (GTM) method. We found that Mean-VOI WBRs values were strongly affected by PVE. WBRs obtained by the physician measurement, by the Max method and by the Max-RC method were more accurate than WBRs obtained with the Mean-VOI approach. However Expert, Max and Max-RC WBRs strongly depended on the wall thickness. Only the GTM corrected WBRs did not depend on the wall thickness. Using the GTM method, we obtained more reproducible ratio values that could be compared across wall thickness. Yet, the feasibility of the implementation of a GTM-like method on real data remains to be studied.

Burg, S.; Dupas, A.; Stute, S.; Dieudonné, A.; Huet, P.; Le Guludec, D.; Buvat, I.

2013-11-01

142

MRI-based correction for PET partial volume effects in the presence of heterogeneity in gray matter radioactivity  

SciTech Connect

Quantitation of small structures with PET may be inaccurate due to partial volume averaging of surrounding structures. We have previously described a method of correcting PET data for the effects of partial volume averaging on gray matter quantitation. This method may incompletely correct gray matter structures when local tissue concentrations are highly heterogenous. We present an extension of our previous method that by accounting for gray matter heterogeneity, allows for partial volume correction in small structures that can be delineated on MR images. Spoiled gradient echo MR data were acquired coplanar to the PET imaging plane. For each PET slice, 17 contiguous 1.5 mm-thick MR images were tri-segmented into gray matter, white matter, matter maps were created by and the for gray a second step, the structure of for volume and spill-in from surrounding gray and white matter. PET images simulated from MR data from patients with Alzheimer disease and controls demonstrated full recovery of tracer concentration in the amygdala over a range of contrasts (from that of white matter to 4x gray matter) (error = 0.36{plus_minus}0.29%) and sizes (152-725mm{sup 3}) (error = 0.11{plus_minus}0.17%). The method was validated with sphere phantoms and a 5-compartment brain phantom in actual PET acquisitions. This newly developed and validated MR-based partial volume correction algorithm for PET, accurately derives non-homogeneous gray matter radioactivity concentrations and should improve quantitation of subcortical structures.

Meltzer, C.C.; Zubieta, J.K.; Links, J.M. [Johns Hopkins Medical Institutions, Baltimore, MD (United States)] [and others

1994-05-01

143

Molar distalization with bimetric molar distalization arches.  

PubMed

The aim of this study was to observe the clinical and cephalometric effects of intra-oral distalization with the maxillary bimetric arches. 3 girls and 1 boy with a mean age of 13.5 years with Class II skeletal and dental relationship were selected. Care was taken to select patients having a normal vertical growth pattern. Lateral cephalograms were taken at the beginning and at the end of the distalization period, which was approximately 3 months. To observe the distal movement, a metal marker was attached to the distal end of the buccal tube of the first molar. On each lateral cephalometric radiograph a reference plane perpendicular to the occlusal plane and passing through the point Sella was drawn to assess the amount of distalization. Cephalometric measurements indicated that the upper molars moved approximately 3 mm distally and that the lower incisors were proclined. PMID:9582621

Küçükkele?, N; Do?anay, A

1994-09-01

144

Molar mass distribution and solubility modeling of asphaltenes  

SciTech Connect

Attempts to model asphaltene solubility with Scatchard-Hildebrand theory were hampered by uncertainty in molar volume and solubility parameter distribution within the asphaltenes. By considering asphaltenes as a series of polyaromatic hydrocarbons with randomly distributed associated functional groups, molar volume and solubility parameter distributions are calculated from experimental measurements of molar mass and density. The molar mass distribution of Athabasca asphaltenes is determined from interfacial tension and vapor pressure osmometry measurements together with plasma desorption mass spectrometry determinations from the literature. Asphaltene densities are calculated indirectly from mixtures of known concentration of asphaltene in toluene. Asphaltene density, molar volume, and solubility parameter are correlated with molar mass. Solid-liquid equilibrium calculations based on solubility theory and the asphaltene property correlations successfully predict experimental data for both the precipitation point and the amount of precipitated asphaltenes in toluene-hexane solvent mixtures.

Yarranton, H.W.; Masliyah, J.H. [Univ. of Alberta, Edmonton, Alberta (Canada). Dept. of Chemical Engineering

1996-12-01

145

Symmetric geometric transfer matrix partial volume correction for PET imaging: principle, validation and robustness.  

PubMed

Limited spatial resolution of positron emission tomography (PET) often requires partial volume correction (PVC) to improve the accuracy of quantitative PET studies. Conventional region-based PVC methods use co-registered high resolution anatomical images (e.g. computed tomography (CT) or magnetic resonance images) to identify regions of interest. Spill-over between regions is accounted for by calculating regional spread functions (RSFs) in a geometric transfer matrix (GTM) framework. This paper describes a new analytically derived symmetric GTM (sGTM) method that relies on spill-over between RSFs rather than between regions. It is shown that the sGTM is mathematically equivalent to Labbe's method; however it is a region-based method rather than a voxel-based method and it avoids handling large matrices. The sGTM method was validated using two three-dimensional (3D) digital phantoms and one physical phantom. A 3D digital sphere phantom with sphere diameters ranging from 5 to 30 mm and a sphere-to-background uptake ratio of 3-to-1 was used. A 3D digital brain phantom was used with four different anatomical regions and a background region with different activities assigned to each region. A physical sphere phantom with the same geometry and uptake as the digital sphere phantom was manufactured and PET-CT images were acquired. Using these three phantoms, the performance of the sGTM method was assessed against that of the GTM method in terms of accuracy, precision, noise propagation and robustness. The robustness was assessed by applying mis-registration errors and errors in estimates of PET point spread function (PSF). In all three phantoms, the results showed that the sGTM method has accuracy similar to that of the GTM method and within 5%. However, the sGTM method showed better precision and noise propagation than the GTM method, especially for spheres smaller than 13 mm. Moreover, the sGTM method was more robust than the GTM method when mis-registration errors or errors in estimates of PSF occur. The improved robustness was more pronounced for smaller objects. In conclusion, the sGTM method was analytically derived and validated. The noise characteristics and robustness of the sGTM method were better than the conventional GTM method. PMID:23051703

Sattarivand, Mike; Kusano, Maggie; Poon, Ian; Caldwell, Curtis

2012-10-10

146

Regional changes of cortical mean diffusivities with aging after correction of partial volume effects  

PubMed Central

Accurately measuring the cortical mean diffusivity (MD) derived from diffusion tensor imaging (DTI) at the comprehensive lobe, gyral and voxel level of young, elderly healthy brains and those with Alzheimer's disease (AD) may provide insights on heterogeneous cortical microstructural changes caused by aging and AD. Due to partial volume effects (PVE), the measurement of cortical MD is overestimated with contamination of cerebrospinal fluid (CSF). The bias is especially severe for aging and AD brains because of significant cortical thinning of these brains. In this study, we aimed to quantitatively characterize the unbiased regional cortical MD changes due to aging and AD and delineate the effects of cortical thinning of elderly healthy and AD groups on MD measurements. DTI and T1-weighted images of 14 young, 15 elderly healthy subjects and 17 AD patients were acquired. With the parcellated cortical gyri and lobes from T1 weighted image transformed to DTI, regional cortical MD of all subjects before and after PVE correction were measured. CSF contamination model was used to correct bias of MD caused by PVE. Compared to cortical MD of young group, significant increases of corrected MD for elderly healthy and AD groups were found only in frontal and limbic regions, respectively, while there were significant increases of uncorrected MD all over the cortex. Uncorrected MD are significantly higher in limbic and temporal gyri in AD group, compared to those in elderly healthy group but higher MD only remained in limbic gyri after PVE correction. Cortical thickness was also measured for all groups. The correlation slopes between cortical MD and thickness for elderly healthy and AD groups were significantly decreased after PVE correction compared to before correction while no significant change of correlation slope was detected for young group. It suggests that the cortical thinning in elderly healthy and AD groups is a significant contributor to the bias of uncorrected cortical MD measurement. The established comprehensive unbiased cortical MD profiles of young, elderly healthy subjects and AD patients at the lobe, gyral and voxel level may serve as clinical references for cortical microstructure.

Jeon, Tina; Mishra, Virendra; Uh, Jinsoo; Weiner, Myron; Hatanpaa, Kimmo J.; White, Charles L.; Zhao, Yan D.; Lu, Hanzhang; Diaz-Arrastia, Ramon; Huang, Hao

2012-01-01

147

Symmetric geometric transfer matrix partial volume correction for PET imaging: principle, validation and robustness  

NASA Astrophysics Data System (ADS)

Limited spatial resolution of positron emission tomography (PET) often requires partial volume correction (PVC) to improve the accuracy of quantitative PET studies. Conventional region-based PVC methods use co-registered high resolution anatomical images (e.g. computed tomography (CT) or magnetic resonance images) to identify regions of interest. Spill-over between regions is accounted for by calculating regional spread functions (RSFs) in a geometric transfer matrix (GTM) framework. This paper describes a new analytically derived symmetric GTM (sGTM) method that relies on spill-over between RSFs rather than between regions. It is shown that the sGTM is mathematically equivalent to Labbe's method; however it is a region-based method rather than a voxel-based method and it avoids handling large matrices. The sGTM method was validated using two three-dimensional (3D) digital phantoms and one physical phantom. A 3D digital sphere phantom with sphere diameters ranging from 5 to 30 mm and a sphere-to-background uptake ratio of 3-to-1 was used. A 3D digital brain phantom was used with four different anatomical regions and a background region with different activities assigned to each region. A physical sphere phantom with the same geometry and uptake as the digital sphere phantom was manufactured and PET-CT images were acquired. Using these three phantoms, the performance of the sGTM method was assessed against that of the GTM method in terms of accuracy, precision, noise propagation and robustness. The robustness was assessed by applying mis-registration errors and errors in estimates of PET point spread function (PSF). In all three phantoms, the results showed that the sGTM method has accuracy similar to that of the GTM method and within 5%. However, the sGTM method showed better precision and noise propagation than the GTM method, especially for spheres smaller than 13 mm. Moreover, the sGTM method was more robust than the GTM method when mis-registration errors or errors in estimates of PSF occur. The improved robustness was more pronounced for smaller objects. In conclusion, the sGTM method was analytically derived and validated. The noise characteristics and robustness of the sGTM method were better than the conventional GTM method.

Sattarivand, Mike; Kusano, Maggie; Poon, Ian; Caldwell, Curtis

2012-11-01

148

Field measurements of soot volume fractions in laminar partially premixed coflow ethylene\\/air flames  

Microsoft Academic Search

The conditions under which soot is formed vary widely and depend upon several factors, including pressure, temperature, fuel type, combustor geometry, and extent of premixing. Although it is known that partially premixed flames (PPFs) can become either more or less sooting than their nonpremixed or premixed counterparts, the impact of partial premixing on soot formation across a large equivalence ratio

Claudya P. Arana; Mariusz Pontoni; Swarnendu Sen; Ishwar K. Puri

2004-01-01

149

A novel neutron computed tomography partial volume voxel water quantification technique  

NASA Astrophysics Data System (ADS)

Since neutrons are attenuated by small amounts of water, but readily penetrate most metals, neutron imaging is ideal for the observation and quantification of water mass in operating hydrogen-powered polymer electrolyte fuel cells (PEFCs). PEFC's have a special need for non-destructive analysis techniques for the imaging of liquid water because the liquid water stored in the porous media can be a source of reduced performance, degradation and cause more lethargic start-up from freezing conditions. Traditional two-dimensional (2D) neutron radioscopy has been successfully applied to the quantification of liquid water in PEFC's, but it suffers from the drawback of making it difficult to determine the exact "depth" within a PEFC the liquid water mass exists. Neutron computed tomography (NCT) produces a three-dimensional (3D) volumetric reconstruction that offers the ability to determine the exact spatial location of a liquid water mass within a PEFC. This makes possible the isolation of liquid water slugs that can block the channels of either the anode or cathode reactant flow fields. Water mass quantification of these slugs would provide insight into improving PEFC design. Thus, a method was developed for the precise quantification of water mass in neutron computed tomography (NCT) reconstructions. A three-dimensional (3D) volumetric reconstruction is comprised of individual volume elements, or voxels. The gray level value of a voxel represents the total macroscopic cross section, Sigmat, of the material present at the voxel's spatial location. For voxels along interfaces, the gray level represents a combination of Sigmats for the various materials present. The fractional amount of water, also known as a partial volume, represented by such a voxel must be quantified for an accurate result. This calculation requires removing or compensating for the influence of other materials on the voxel's gray level. This is accomplished by background normalizing the raw data used to produce the volumetric reconstruction. The resulting volumetric reconstruction contains voxels that represent only water. Normalizing to the gray level value of a voxel of known water mass produces a matrix of voxels with gray levels that now represent fractional amounts of water. These fractional amounts are tallied and multiplied by the known water mass of the normalizing voxel to determine the total. The NCT water quantification technique was tested using MCNP simulations of samples containing liquid phase water and ice phase water. Quantification of the MCNP simulations yielded results within 0.2% of the theoretical. For liquid phase and ice phase water samples at ˜30mm from the detector, results were within 2% of the theoretical. The ability to quantify an ice water mixture to within 2% of the theoretical was also demonstrated. For liquid phase water samples at 140mm from the detector, significant error in the quantified water mass, as large as 47%, was observed and determined to be the result of geometric un-sharpness effects and cupping artifacts. Deconvolution of the imaging system's blurring function was performed to correct for the geometric un-sharpness. Results of the devoncolution showed a reduction in the geometric un-sharpness by ˜14.4% yielding an average increase in quantified water mass of 6.7%. The effects of magnification, cupping artifacts, and geometric unsharpness on the final quantification results were also investigated. Magnification was determined to have no effect while cupping artifacts accounted for 1.4% of the error. Geometric un-sharpness accounted for 45% of the error, making it the dominant source of error.

Heller, Arthur Kevin

150

New Measurements of the Densities of Copper and Nickel-Sulfide Liquids and Preliminary Estimates of the Partial Molar Volumes of Cu, Ni, S and O  

Microsoft Academic Search

We present the results of density measurements in Ni- and Cu-sulfide liquids. Density measurements were performed in-situ at 1250° C under controlled-atmosphere conditions using the modified single-bob (MSB) Archimedean method. The MSB consists of a ~2 mm diameter rod with a ~6 mm long ~7 mm diameter cylindrical bob attached ~7 mm from the base of the rod. The bob

V. C. Kress; M. S. Ghiorso

2001-01-01

151

Pressure-controlled high-performance liquid chromatographic study on the influence of rim chemistry on partial molar volume differences between free and complexed cyclodextrins  

Microsoft Academic Search

Pragmatic comparison of pressure dependent retention for differing cyclodextrin rim chemistries is assessed using controlled-pressure HPLC. For pressure differences of <300 bar, systematic shifts in solute capacity factor are observed for both native and methylated ?-cyclodextrin stationary phases. In addition to the importance of this observation for the practice of liquid chromatography, this technique can also be implemented in the

Moira C. Ringo; Christine E. Evans

1999-01-01

152

Effects of dissolved electrolytes on the solubility and partial molar volume of helium in water from 50 to 400 atmospheres at 25°C  

Microsoft Academic Search

The solubility of helium in water and aqueous CsCl, NaCl and MgCl2 solutions at concentrations up to 3.380 molal has been measured at 50 atm intervals from 50 to 400 atm at 25°C. Setschenow coefficients for helium are practically invariant with pressure in each solution, decrease significantly with increasing electrolyte concentration and vary with the type of electrolyte in a

Wayne A. Gerth

1983-01-01

153

Partial specific volume of poly[2,2-bis(4-hydroxyphenyl)butane-co-phosgene  

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.

154

Partial specific volume of poly[1,1-bis(4-hydroxyphenyl)-1-phenylethane-co-phosgene  

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.

155

Partial specific volume of poly(vinyl acetate-co-vinyl chloride)  

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.

156

Endodontic treatment of molars  

PubMed Central

Objective Commissioned by the German Institute of Medical Documentation and Information (DIMDI) the Austrian Health Institute (ÖBIG) prepared a HTA report on the long-term effectiveness of endodontic treatment (root canal treatment, RCT) of molars. The focus is to examine factors influencing the outcome of endodontic treatment and showing their impact on long-term results. Additionally, economic aspects of root canal treatment in Germany are discussed. Methodology By performing a systematic literature search in 29 databases (e.g. MEDLINE), the Cochrane Library and by hand searching two peer-reviewed endodontic journals the authors could identify 750 relevant articles, of which finally 18 qualified for assessment. Results The findings show that the most relevant factor influencing the long-term outcome of endodontic treatment is the preoperative status of a tooth. The lowest success rates are reported for molars with a preoperative devital or necrotic pulp and persisting periapical lesions (so called periapical disease). Discussion Even if there is no positive selection of patients and the RCT is performed by a normal dentist rather than an endodontist - a fact which is very common - long-term success rates of more then 90% are possible. The overall success rates for endodontic treatment of molars therefore seem to be similar to those of other tooth-types. Conclusions Especially primary, conventional (i.e. non-surgical) root canal treatment is an effective and efficient therapy for endodontically ill molars, especially if no large periapical lesion persists. Nonetheless, a long term successful endodontic therapy requires a thorough assessment of the pre-operative status of the molar and treatment according to established guidelines.

Habl, Claudia; Bodenwinkler, Andrea; Sturzlinger, Heidi

2006-01-01

157

VAPOR PRESSURES, LIQUID MOLAR VOLUMES, VAPOR NON-IDEALITIES, AND CRITICAL PROPERTIES OF SOME FLUORINATED ETHERS: CF3OCF2OCF3, CF3OCF2CF2H, C-CF2CF2CF2O, CF3OCF2H, AND CF3OCH3; AND OF CCL3F AND CF2CLH  

EPA Science Inventory

The paper reports results of measurements of vapor pressures, compressibilities, expansivities, and molar volumes of the liquid phase between room temperature and the critical temperature for a series of fluorinated ethers: CF3OCF2-OCF3, CF3OCF2CF2H, c- CF2CF2CF2O, CF3OCF2H, and ...

158

Vapor Pressures, Liquid Molar Volumes, Vapor Non-Idealities, and Critical Properties of Some Fluorinated Ethers: CF3OCF2OCF3, CF3OCF2CF2H, c-CF2CF2CF2O, CF3OCF2H, and CF3OCH3; and of CCI3F and CF2CIH.  

National Technical Information Service (NTIS)

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 CF3...

B. H. Wang J. L. Adcock S. B. Mathur W. A. Van Hook

1991-01-01

159

Can histopathologists reliably diagnose molar pregnancy?  

PubMed Central

AIMS--To assess the degree of difficulty in diagnosing partial mole by analysing intraobserver and interobserver agreement among a group of pathologists for these diagnoses. METHODS--Fifty mixed cases of partial mole, complete mole, and non-molar pregnancy were submitted to seven histopathologists, two of whom are expert gynaecological pathologists; the other five were district general hospital consultants, one of whom works in Australia. These participants gave each slide a firm diagnosis of either partial mole, complete mole, or non-molar pregnancy. Some 12 months later, the slides were recorded and again submitted for a second diagnostic round to assess intraobserver as well as interobserver agreement. Standard histological criteria for each diagnostic category were circulated with the slides. RESULTS--kappa statistics showed that complete mole could be reliably distinguished from non-molar pregnancy, but neither non-molar pregnancy nor complete mole could be easily differentiated from partial mole. In only 35 out of 50 cases was there agreement between five or more of the seven participants. Agreement between the expert gynaecological pathologists was no better than for others in the group. Interestingly, the intraobserver agreement for each pathologist was good to excellent. CONCLUSIONS--These results imply that the reported histological criteria are either not being applied consistently or that they are lacking in practical use. An atypical growth pattern of trophoblast, rather than the polar accentuation seen in normal first trimester pregnancies, seems to be the important diagnostic histological feature for partial mole. Ploidy studies might also help with problem cases. Images

Howat, A J; Beck, S; Fox, H; Harris, S C; Hill, A S; Nicholson, C M; Williams, R A

1993-01-01

160

Quantification of human high-energy phosphate metabolite concentrations at 3?T with partial volume and sensitivity corrections.  

PubMed

Practical noninvasive methods for the measurement of absolute metabolite concentrations are key to the assessment of the depletion of myocardial metabolite pools which occurs with several cardiac diseases, including infarction and heart failure. Localized MRS offers unique noninvasive access to many metabolites, but is often confounded by nonuniform sensitivity and partial volume effects in the large, poorly defined voxels commonly used for the detection of low-concentration metabolites with surface coils. These problems are exacerbated at higher magnetic field strengths by greater radiofrequency (RF) field inhomogeneity and differences in RF penetration with heteronuclear concentration referencing. An example is the (31) P measurement of cardiac adenosine triphosphate (ATP) and phosphocreatine (PCr) concentrations, which, although central to cardiac energetics, have not been measured at field strengths above 1.5?T. Here, practical acquisition and analysis protocols are presented for the quantification of [PCr] and [ATP] with one-dimensionally resolved surface coil spectra and concentration referencing at 3?T. The effects of nonuniform sensitivity and partial tissue volumes are addressed at 3?T by the application of MRI-based three-dimensional sensitivity weighting and tissue segmentation. The method is validated in phantoms of different sizes and concentrations, and used to measure [PCr] and [ATP] in healthy subjects. In calf muscle (n?=?8), [PCr]?=?24.7?±?3.4 and [ATP]?=?5.7?±?1.3?µmol/g wet weight, whereas, in heart (n?=?18), [PCr]?=?10.4?±?1.5 and [ATP]?=?6.0?±?1.1?µmol/g wet weight (all mean?±?SD), consistent with previous reports at lower fields. The method enables, for the first time, the efficient, semi-automated quantification of high-energy phosphate metabolites in humans at 3?T with nonuniform excitation and detection. Copyright © 2013 John Wiley & Sons, Ltd. PMID:23729378

El-Sharkawy, Abdel-Monem M; Gabr, Refaat E; Schär, Michael; Weiss, Robert G; Bottomley, Paul A

2013-06-03

161

Topology-corrected segmentation and local intensity estimates for improved partial volume classification of brain cortex in MRI.  

PubMed

In magnetic resonance imaging (MRI), accuracy and precision with which brain structures may be quantified are frequently affected by the partial volume (PV) effect. PV is due to the limited spatial resolution of MRI compared to the size of anatomical structures. Accurate classification of mixed voxels and correct estimation of the proportion of each pure tissue (fractional content) may help to increase the precision of cortical thickness estimation in regions where this measure is particularly difficult, such as deep sulci. The contribution of this work is twofold: on the one hand, we propose a new method to label voxels and compute tissue fractional content, integrating a mechanism for detecting sulci with topology preserving operators. On the other hand, we improve the computation of the fractional content of mixed voxels using local estimation of pure tissue intensity means. Accuracy and precision were assessed using simulated and real MR data and comparison with other existing approaches demonstrated the benefits of our method. Significant improvements in gray matter (GM) classification and cortical thickness estimation were brought by the topology correction. The fractional content root mean squared error diminished by 6.3% (p<0.01) on simulated data. The reproducibility error decreased by 8.8% (p<0.001) and the Jaccard similarity measure increased by 3.5% on real data. Furthermore, compared with manually guided expert segmentations, the similarity measure was improved by 12.0% (p<0.001). Thickness estimation with the proposed method showed a higher reproducibility compared with the measure performed after partial volume classification using other methods. PMID:20193712

Rueda, Andrea; Acosta, Oscar; Couprie, Michel; Bourgeat, Pierrick; Fripp, Jurgen; Dowson, Nicholas; Romero, Eduardo; Salvado, Olivier

2010-03-01

162

Taurodontism in deciduous molars.  

PubMed

Taurodont teeth are characterised by large pulp chambers at the expense of roots. An enlarged pulp chamber, apical displacement of the pulpal floor and no constriction at the level of the cement-enamel junction are the characteristic features of taurodont tooth. It appears more frequently as an isolated anomaly but its association with syndromes and other abnormalities have also been reported. Permanent dentition is more commonly affected than deciduous dentition. This paper presents a case report of taurodontism in relation to mandibular deciduous second molars. PMID:23737594

Bafna, Yash; Kambalimath, H V; Khandelwal, Vishal; Nayak, Prathibha

2013-06-03

163

Comparative assessment of statistical brain MR image segmentation algorithms and their impact on partial volume correction in PET.  

PubMed

Magnetic resonance imaging (MRI)-guided partial volume effect correction (PVC) in brain positron emission tomography (PET) is now a well-established approach to compensate the large bias in the estimate of regional radioactivity concentration, especially for small structures. The accuracy of the algorithms developed so far is, however, largely dependent on the performance of segmentation methods partitioning MRI brain data into its main classes, namely gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF). A comparative evaluation of three brain MRI segmentation algorithms using simulated and clinical brain MR data was performed, and subsequently their impact on PVC in 18F-FDG and 18F-DOPA brain PET imaging was assessed. Two algorithms, the first is bundled in the Statistical Parametric Mapping (SPM2) package while the other is the Expectation Maximization Segmentation (EMS) algorithm, incorporate a priori probability images derived from MR images of a large number of subjects. The third, here referred to as the HBSA algorithm, is a histogram-based segmentation algorithm incorporating an Expectation Maximization approach to model a four-Gaussian mixture for both global and local histograms. Simulated under different combinations of noise and intensity non-uniformity, MR brain phantoms with known true volumes for the different brain classes were generated. The algorithms' performance was checked by calculating the kappa index assessing similarities with the "ground truth" as well as multiclass type I and type II errors including misclassification rates. The impact of image segmentation algorithms on PVC was then quantified using clinical data. The segmented tissues of patients' brain MRI were given as input to the region of interest (RoI)-based geometric transfer matrix (GTM) PVC algorithm, and quantitative comparisons were made. The results of digital MRI phantom studies suggest that the use of HBSA produces the best performance for WM classification. For GM classification, it is suggested to use the EMS. Segmentation performed on clinical MRI data show quite substantial differences, especially when lesions are present. For the particular case of PVC, SPM2 and EMS algorithms show very similar results and may be used interchangeably. The use of HBSA is not recommended for PVC. The partial volume corrected activities in some regions of the brain show quite large relative differences when performing paired analysis on 2 algorithms, implying a careful choice of the segmentation algorithm for GTM-based PVC. PMID:16828315

Zaidi, Habib; Ruest, Torsten; Schoenahl, Frederic; Montandon, Marie-Louise

2006-07-07

164

Molar and incisor changes with Wilson rapid molar distalization.  

PubMed

The purpose of this study was to determine the magnitude and direction of maxillary and mandibular first molar and incisor changes that occur during Class II molar correction with Wilson "rapid molar distalization." Nineteen patients (13 females, 6 males) were selected from the clinic at Loma Linda University Department of Orthodontics. All patients received maxillary bimetric distalizing arches (BDA), and either a mandibular three-dimensional lingual arch, with or without a passive 0.016 x 0.016-inch utility arch, or a traditional edgewise full banded and bonded arch. The arches were activated with open coil spring and Class II intermaxillary elastics. A total of five activations were completed or until visual inspection revealed a Class I molar relation. Prestudy and poststudy lateral cephalometric radiographs were taken with molar bands cemented. Dental changes were determined, with Ricketts superimpositions. The mean change in molar relation measured at the occlusal plane was 4.1 mm. The mean maxillary molar distalization was 2.16 mm, with 7.8 degrees of tip. The rate of maxillary molar movement was 0.56 mm per month. The mean mandibular molar mesial movement was 1.38 mm. The maxillary incisors protruded a mean of 0.3 mm, and extruded a mean of 1.6 mm. Except for the edgewise sample, all mandibular molars moved mesially further than the incisors, reducing the mandibular arch length. The presence of erupted maxillary second molars did not correlate with the rate of maxillary first molar movement, magnitude of movement, or amount of tipping that occurred. PMID:8249931

Muse, D S; Fillman, M J; Emmerson, W J; Mitchell, R D

1993-12-01

165

Maxillary first permanent molar impaction. A conservative treatment approach.  

PubMed

The objective of this clinical case is to suggest a treatment approach for impaction of the maxillary first permanent molars. This approach allows access to the partially erupted tooth for orthodontic bonding and utilization of loops for distalization. An important detail is the non inclusion of the primary second molar in the orthodontic mechanics, in order to reduce the risk of early loss and preserve this tooth until exfoliation. PMID:16491975

Rizzatto, Susana Maria Deon; de Menezes, Luciane Macedo; do Rego, Marcus Vinicius Neiva Nunes; Thiesen, Guilherme; de Araujo, Vanessa Pereira; Freitas, Maria Perpétua Mota

2005-01-01

166

Fifth alternative for replacement of maxillary first molar.  

PubMed

There are occasions when the patient is missing only one first molar or the first molar is slated for an odontectomy (extraction). Most of the time, there are only four common avenues for replacement: partial removable prosthesis, Maryland bridge, ceramic or ceramic to metal fixed prosthesis and osseo-integrated implant supported crown. In this article, the author discusses the least common avenue for replacement of missing maxillary first molar--an orthodontic closure. He discusses and demonstrates; Maximum, Medium and Minimum Anchorage strategies on acrylic models. Preserving the anchorage is necessary for successful execution of this orthodontic procedure. This demonstration is followed by presentation of the actual case. PMID:23941033

Palencar, Adrian J

2013-01-01

167

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...

168

Surveillance without chemotherapy in a woman with recurrent molar pregnancy.  

PubMed

A 27-year-old fouth gravida patient with previous two partial molar pregnancies and one missed abortion underwent a suction evacuation for partial molar pregnancy at 9 weeks of gestation. She was followed up with serum HCG values. Though the HCG level reduced from a pre-evacuation value of 1 40 223-31 157 mIU/ml 1 week post procedure, the levels continued to be positive in low titres 6 months after suction evacuation. The management options were discussed with the patient and a decision was taken to continue surveillance with serial HCG titres. HCG levels normalised after 11 months without the need for chemotherapy. PMID:23429019

Bagga, Rashmi; Siwatch, Sujata; Srinivasan, Radhika; Dhaliwal, Lakhbir Kaur

2013-02-20

169

A three-dimensional model-based partial volume correction strategy for gated cardiac mouse PET imaging  

NASA Astrophysics Data System (ADS)

Quantification in cardiac mouse positron emission tomography (PET) imaging is limited by the imaging spatial resolution. Spillover of left ventricle (LV) myocardial activity into adjacent organs results in partial volume (PV) losses leading to underestimation of myocardial activity. A PV correction method was developed to restore accuracy of the activity distribution for FDG mouse imaging. The PV correction model was based on convolving an LV image estimate with a 3D point spread function. The LV model was described regionally by a five-parameter profile including myocardial, background and blood activities which were separated into three compartments by the endocardial radius and myocardium wall thickness. The PV correction was tested with digital simulations and a physical 3D mouse LV phantom. In vivo cardiac FDG mouse PET imaging was also performed. Following imaging, the mice were sacrificed and the tracer biodistribution in the LV and liver tissue was measured using a gamma-counter. The PV correction algorithm improved recovery from 50% to within 5% of the truth for the simulated and measured phantom data and image uniformity by 5-13%. The PV correction algorithm improved the mean myocardial LV recovery from 0.56 (0.54) to 1.13 (1.10) without (with) scatter and attenuation corrections. The mean image uniformity was improved from 26% (26%) to 17% (16%) without (with) scatter and attenuation corrections applied. Scatter and attenuation corrections were not observed to significantly impact PV-corrected myocardial recovery or image uniformity. Image-based PV correction algorithm can increase the accuracy of PET image activity and improve the uniformity of the activity distribution in normal mice. The algorithm may be applied using different tracers, in transgenic models that affect myocardial uptake, or in different species provided there is sufficient image quality and similar contrast between the myocardium and surrounding structures.

Dumouchel, Tyler; Thorn, Stephanie; Kordos, Myra; DaSilva, Jean; Beanlands, Rob S. B.; deKemp, Robert A.

2012-07-01

170

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...

171

Infield and out-of-field effects in partial volume lung irradiation in rodents: Possible correlation between early dna damage and functional endpoints  

Microsoft Academic Search

Purpose: Recent observations have shown that there are regional variations in radiation response in mouse lung as measured by functional assays. Furthermore, there are both in-field and out-of-field effects in radiation-induced lung damage as observed by DNA assay in rats. The purpose of this work is: (a) to examine mice lethality data following partial volume lung irradiation to assess the

Vitali V Moiseenko; Jerry J Battista; Richard P Hill; Elizabeth L Travis; Jake Van Dyk

2000-01-01

172

Lung Dose-Volume Parameters and the Risk of Pneumonitis for Patients Treated With Accelerated Partial-Breast Irradiation Using Three-Dimensional Conformal Radiotherapy  

Microsoft Academic Search

Purpose There are no data on how complication rates after accelerated partial-breast irradiation delivered by three-dimensional conformal radiotherapy are affected by treatment technique. We therefore examined the risk of pneumonitis in relation to lung dose-volume parameters. Patients and Methods Our prospective dose-escalation trial enrolled 198 treated patients from 2003 to 2007. Patients received 32 or 36 Gy in 4-Gy fractions,

Abram Recht; Marek Ancukiewicz; M. A. Alm El-Din; Xing-Qi Lu; Chrystalla Martin; Stuart M. Berman; Ariel E. Hirsch; Lisa A. Kachnic; Angela Katz; Shannon MacDonald; Elena A. Nedea; Mary Ann Stevenson; Simon N. Powell; Alphonse G. Taghian

2009-01-01

173

Automatic Delineation of Sulci and Improved Partial Volume Classification for Accurate 3D Voxel-Based Cortical Thickness Estimation from MR  

Microsoft Academic Search

\\u000a Accurate cortical thickness estimation in-vivo is important for the study of many neurodegenerative diseases. When using magnetic resonance images (MRI), accuracy may be\\u000a hampered by artifacts such as partial volume (PV) as the cortex spans only a few voxels. In zones of opposed sulcal banks\\u000a (tight sulci) the measurement can be even more difficult. The aim of this work is

Oscar Acosta; Pierrick Bourgeat; Jurgen Fripp; Erik Bonner; Sébastien Ourselin; Olivier Salvado

2008-01-01

174

Densities and apparent molar volumes of atmospherically important electrolyte solutions. 2. The systems H(+)-HSO4(-)-SO4(2-)-H2O from 0 to 3 mol kg(-1) as a function of temperature and H(+)-NH4(+)-HSO4(-)-SO4)2-)-H2O from 0 to 6 mol kg(-1) at 25 °C using a Pitzer ion interaction model, and NH4HSO4-H2O and (NH4)3H(SO4)2-H2O over the entire concentration range.  

PubMed

A Pitzer ion interaction model has been applied to the systems H(2)SO(4)-H(2)O (0-3 mol kg(-1), 0-55 °C) and H(2)SO(4)-(NH(4))(2)SO(4)-H(2)O (0-6 mol kg(-1), 25 °C) for the calculation of apparent molar volume and density. The dissociation reaction HSO(4)(-)((aq)) ? H(+)((aq)) + SO(4)(2-)((aq)) is treated explicitly. Apparent molar volumes of the SO(4)(2-) ion at infinite dilution were obtained from part 1 of this work, (1) and the value for the bisulfate ion was determined in this study from 0 to 55 °C. In dilute solutions of both systems, the change in the degree of dissociation of the HSO(4)(-) ion with concentration results in much larger variations of the apparent molar volumes of the solutes than for conventional strong (fully dissociated) electrolytes. Densities and apparent molar volumes are tabulated. Apparent molar volumes calculated using the model are combined with other data for the solutes NH(4)HSO(4) and (NH(4))(3)H(SO(4))(2) at 25 °C to obtain apparent molar volumes and densities over the entire concentration range (including solutions supersaturated with respect to the salts). PMID:21438500

Clegg, S L; Wexler, A S

2011-03-25

175

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

2013-07-26

176

Automatic delineation of sulci and improved partial volume classification for accurate 3D voxel-based cortical thickness estimation from MR.  

PubMed

Accurate cortical thickness estimation in-vivo is important for the study of many neurodegenerative diseases. When using magnetic resonance images (MRI), accuracy may be hampered by artifacts such as partial volume (PV) as the cortex spans only a few voxels. In zones of opposed sulcal banks (tight sulci) the measurement can be even more difficult. The aim of this work is to propose a voxel-based cortical thickness estimation method from MR by integrating a mechanism for correcting sulci delineation after an improved partial volume classification. First, an efficient and accurate framework was developed to enhance partial volume classification with structural information. Then, the correction of sulci delineation is performed after a homotopic thinning of a cost function image. Integrated to our voxel-based cortical thickness estimation pipeline, the overall method showed a better estimate of thickness and a high reproducibility on real data (R2 > 0.9). A quantitative analysis on clinical data from an Alzheimer's disease study showed significant differences between normal controls and Alzheimer's disease patients. PMID:18979755

Acosta, Oscar; Bourgeat, Pierrick; Fripp, Jurgen; Bonner, Erik; Ourselin, Sébastien; Salvado, Olivier

2008-01-01

177

Automated voxel-based 3D cortical thickness measurement in a combined Lagrangian-Eulerian PDE approach using partial volume maps.  

PubMed

Accurate cortical thickness estimation is important for the study of many neurodegenerative diseases. Many approaches have been previously proposed, which can be broadly categorised as mesh-based and voxel-based. While the mesh-based approaches can potentially achieve subvoxel resolution, they usually lack the computational efficiency needed for clinical applications and large database studies. In contrast, voxel-based approaches, are computationally efficient, but lack accuracy. The aim of this paper is to propose a novel voxel-based method based upon the Laplacian definition of thickness that is both accurate and computationally efficient. A framework was developed to estimate and integrate the partial volume information within the thickness estimation process. Firstly, in a Lagrangian step, the boundaries are initialized using the partial volume information. Subsequently, in an Eulerian step, a pair of partial differential equations are solved on the remaining voxels to finally compute the thickness. Using partial volume information significantly improved the accuracy of the thickness estimation on synthetic phantoms, and improved reproducibility on real data. Significant differences in the hippocampus and temporal lobe between healthy controls (NC), mild cognitive impaired (MCI) and Alzheimer's disease (AD) patients were found on clinical data from the ADNI database. We compared our method in terms of precision, computational speed and statistical power against the Eulerian approach. With a slight increase in computation time, accuracy and precision were greatly improved. Power analysis demonstrated the ability of our method to yield statistically significant results when comparing AD and NC. Overall, with our method the number of samples is reduced by 25% to find significant differences between the two groups. PMID:19648050

Acosta, Oscar; Bourgeat, Pierrick; Zuluaga, Maria A; Fripp, Jurgen; Salvado, Olivier; Ourselin, Sébastien

2009-07-10

178

Automated voxel-based 3D cortical thickness measurement in a combined Lagrangian-Eulerian PDE approach using partial volume maps  

PubMed Central

Accurate cortical thickness estimation is important for the study of many neurodegenerative diseases. Many approaches have been previously proposed, which can be broadly categorised as mesh-based and voxel-based. While the mesh-based approaches can potentially achieve subvoxel resolution, they usually lack the computational efficiency needed for clinical applications and large database studies. In contrast, voxel-based approaches, are computationally efficient, but lack accuracy. The aim of this paper is to propose a novel voxel-based method based upon the Laplacian definition of thickness that is both accurate and computationally efficient. A framework was developed to estimate and integrate the partial volume information within the thickness estimation process. Firstly, in a Lagrangian step, the boundaries are initialized using the partial volume information. Subsequently, in an Eulerian step, a pair of partial differential equations are solved on the remaining voxels to finally compute the thickness. Using partial volume information significantly improved the accuracy of the thickness estimation on synthetic phantoms, and improved reproducibility on real data. Significant differences in the hippocampus and temporal lobe between healthy controls (NC), mild cognitive impaired (MCI) and Alzheimer’s disease (AD) patients were found on clinical data from the ADNI database. We compared our method in terms of precision, computational speed and statistical power against the Eulerian approach. With a slight increase in computation time, accuracy and precision were greatly improved. Power analysis demonstrated the ability of our method to yield statistically significant results when comparing AD and NC. Overall, with our method the number of samples is reduced by 25% to find significant differences between the two groups.

Acosta, Oscar; Bourgeat, Pierrick; Zuluaga, Maria A.; Fripp, Jurgen; Salvado, Olivier; Ourselin, Sebastien

2010-01-01

179

Solutions : WtPercentToMolarity (4 Variations)  

NSDL National Science Digital Library

A common concentration unit used commercially is percent weight per volume (%W/V) which is the number of grams of solute in 100 mL of solution. A bottle of vinegar contains 5 %W/V acetic acid (CH 3 COOH). What is the molar concentration of acetic acid in the vinegar?

180

Partial specific volume of poly[2,2-bis(4-hydroxy-3-methylphenyl)butane-co-phosgene  

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.

181

Partial specific volume of poly[1,1-bis(4-hydroxy-3-methylphenyl)-1-phenylethane-co-phosgene  

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.

182

Partial specific volume of poly[2,2-bis(4-hydroxy-3-methylphenyl)propane-co-phosgene  

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.

183

Reversibility of the Pulmonary Function Based on the Partial Flow-volume Curve Predicts the Efficacy of Bronchodilator Therapy for Treating Chronic Cough.  

PubMed

Objective Partial expiratory flow-volume curves have the potential to detect mild bronchoconstriction because they are not affected by the modulatory effects of deep inspiration. The aim of this study was to investigate the relationship between the efficacy of bronchodilator therapy (BDT) in treating the cough and to assess the increase in the expiratory flow of the partial flow-volume curve at 40% above the residual volume level (PEF40) caused by treatment with a short-acting beta-2 agonist (SABA) in patients with chronic nonproductive cough. Methods We measured the reversibility of PEF40 caused by a SABA in 42 patients with chronic nonproductive cough at visit 1 (day 0). The patients received BDT for six days. The visual analogue scale (VAS) was used to assess the efficacy of BDT in treating coughing at visit 2 (day 7) (0 mm, 'no cough;' 100 mm, 'no change in coughing'). Results Reversibility of the PEF40 was correlated (r=0.690, p<0.001) with the VAS score determined at visit 2 and was higher in the patients with cough variant asthma (CVA) (44.9±18.3%) than in those with atopic cough (13.4±10.4%) (p<0.01). Conclusion Reversibility of the PEF40 predicted the efficacy of BDT in patients with chronic nonproductive cough and helped to identify patients with CVA. PMID:24042507

Nakade, Yusuke; Fujimura, Masaki; Ohkura, Noriyuki; Nakata, Masako; Nanbu, Yuko; Oe, Hiroyasu; Horita, Hiroshi; Sakai, Yoshio; Wada, Takashi

2013-01-01

184

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

185

Update on molar pregnancy and choriocarcinoma.  

PubMed

The term gestational trophoblastic disease encompasses a wide spectrum of disorders ranging from the benign hydatidiform mole to the malignant choriocarcinoma and placental site trophoblastic tumor. Recent advances in cytogenetics and pathological criteria have brought to light the occurrence of the partial mole, which is probably more common than the complete mole. The World Health Organisation has proposed a classification to rectify the current confusion that exists with clinical and pathological terms. Evacuation of the uterus followed by meticulous followup with sensitive beta subunit Human Chorionic Gonadotropin assay remain the cornerstone of management of molar pregnancy. Prompt chemotherapy is the most important aspect in managing malignant sequelae. Newer chemotherapy regimes have helped to salvage failures from the usual drugs. Judicial use of surgery in metastatic trophoblastic disease can reduce the duration and toxicity of chemotherapy. All patients with gestational trophoblastic disease should be managed in a tertiary care centre with the expertise and facilities easily available to manage these cases. PMID:2694375

Ilancheran, A; Singh, P

1989-10-01

186

Noncompliance unilateral maxillary molar distalization:.  

PubMed

The aim of this prospective study was the three-dimensional (3-D) analysis of tooth movements after unilateral upper molar distalization by means of a noncompliance intraoral appliance, the Keles slider. This appliance exerts a distalizing force of 150 g at approximately the level of the center of resistance of the upper first molar. Twelve patients (six girls and six boys with a mean age of 13.1 years) with a unilateral Class II molar relationship participated in the study. Dental casts were taken immediately before placement and after removal of the appliance. The casts were digitized using a 3-D surface laser scanner and superimposed on a predefined area of the palate. The average unilateral upper first molar distal movement was 3.1 mm (range: 2.4 to 5.3 mm). Anchorage loss was expressed by a 2.1 mm (range: 0.8 to 3.8 mm) proclination of the central incisors and a 6.1 degrees mesial inclination of the ipsilateral first premolar (range: 1.7 degrees to 12.3 degrees ). There was approximately 1 mm of midline deviation toward the contralateral side and a 1.6 mm (range: 0.8 to 2.3 mm) buccal displacement of the contralateral first premolar. A substantial variation was observed among patients. Noncompliance unilateral upper molar distalization was an efficient treatment approach. There was, however, a substantial anchorage loss. Case selection is strongly recommended because significant anterior crowding, ectopic canines, or spacing can lead to significant anchorage loss. PMID:16637715

Mavropoulos, Anestis; Sayinsu, Korkmaz; Allaf, Ferdi; Kiliaridis, Stavros; Papadopoulos, Moschos A; Keles, Ahmet Ozlem

2006-05-01

187

On the volume of solid solutions: an anisotropic approach  

NASA Astrophysics Data System (ADS)

The dependence of the unit cell volume on intensive parameters as temperature T, pressure p, or concentration x is considered in thermodynamic calculations through bulk properties like thermal expansion, compressibility or the partial molar volume. On the other hand, crystal physics takes account of the anisotropy—inherent to crystals—and hence aims at the study of the behaviour of the individual cell parameters through a tensorial description. In this contribution, we show how the established use of the strain tensor can be extended in order to minimize uncertainties or even fallacies in the treatment of the volume of solid solutions.

Peters, L.; Knorr, K.; Schmid-Beurmann, P.; Depmeier, W.

2006-03-01

188

Partial volumes and compressibilities of extended polypeptide chains in aqueous solution: additivity scheme and implication of protein unfolding at normal and high pressure.  

PubMed

An empirical additivity method for calculation of the partial volumes and adiabatic compressibilities of extended oligo- and polypeptides having arbitrary amino acid compositions has been developed and tested by comparison with available experimental data. Its accuracy is the best among the known empirical approaches. Comparison of experimental data on protein denaturation with the results of calculation allows one to discriminate between the unfolded and molten globule states of globular proteins and to estimate the extent of unfolding. For the first time, experimental nonlinear data for the volume-pressure relationship in proteins and model compounds have been used to interpret the high-pressure denaturation of proteins. It has been shown that the two denatured states, molten globule and unfolded ones, can be attained by a pressure rise: the molten globule state by moderate pressure and the unfolded one by high pressure. The relationship between volumetric properties and hydration is briefly discussed. PMID:9254626

Kharakoz, D P

1997-08-19

189

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. Am J Phys Anthropol 152:186-196, 2013. © 2013 Wiley Periodicals, Inc. PMID:24009105

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

2013-09-05

190

Densities and apparent molar volumes of atmospherically important electrolyte solutions. 1. The solutes H2SO4, HNO3, HCl, Na2SO4, NaNO3, NaCl, (NH4)2SO4, NH4NO3, and NH4Cl from 0 to 50 °C, including extrapolations to very low temperature and to the pure liquid state, and NaHSO4, NaOH, and NH3 at 25 °C.  

PubMed

Calculations of the size and density of atmospheric aerosols are complicated by the fact that they can exist at concentrations highly supersaturated with respect to dissolved salts and supercooled with respect to ice. Densities and apparent molar volumes of solutes in aqueous solutions containing the solutes H(2)SO(4), HNO(3), HCl, Na(2)SO(4), NaNO(3), NaCl, (NH(4))(2)SO(4), NH(4)NO(3), and NH(4)Cl have been critically evaluated and represented using fitted equations from 0 to 50 °C or greater and from infinite dilution to concentrations saturated or supersaturated with respect to the dissolved salts. Using extrapolated densities of high-temperature solutions and melts, the relationship between density and concentration is extended to the hypothetical pure liquid solutes. Above a given reference concentration of a few mol kg(-1), it is observed that density increases almost linearly with decreasing temperature, and comparisons with available data below 0 °C suggest that the fitted equations for density can be extrapolated to very low temperatures. As concentration is decreased below the reference concentration, the variation of density with temperature tends to that of water (which decreases as temperature is reduced below 3.98 °C). In this region below the reference concentration, and below 0 °C, densities are calculated using extrapolated apparent molar volumes which are constrained to agree at the reference concentrations with an equation for the directly fitted density. Calculated volume properties agree well with available data at low temperatures, for both concentrated and dilute solutions. Comparisons are made with literature data for temperatures of maximum density. Apparent molar volumes at infinite dilution are consistent, on a single ion basis, to better than ±0.1 cm(3) mol(-1) from 0 to 50 °C. Volume properties of aqueous NaHSO(4), NaOH, and NH(3) have also been evaluated, at 25 °C only. In part 2 of this work (ref 1 ) an ion interaction (Pitzer) model has been used to calculate apparent molar volumes of H(2)SO(4) in 0-3 mol kg(-1) aqueous solutions of the pure acid and to represent directly the effect of the HSO(4)(-) ? H(+) + SO(4)(2-) reaction. The results are incorporated into the treatment of aqueous H(2)SO(4) density described here. Densities and apparent molar volumes from -20 to 50 °C, and from 0 to 100 wt % of solute, are tabulated for the electrolytes listed in the title and have also been incorporated into the extended aerosol inorganics model (E-AIM, http://www.aim.env.uea.ac.uk/aim/aim.php) together with densities of the solid salts and hydrates. PMID:21438504

Clegg, S L; Wexler, A S

2011-03-25

191

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

192

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

193

Molar distalization with the Herbst appliance  

Microsoft Academic Search

This article reviews the dental effects of the Herbst appliance as well as itslong-term effects on the dentition. The Herbst appliance exhibits a pronounced high-pull headgear effect on the maxillary molars. Without retention, the molars tend to return to their former anteroposterior positions after the removal of the appliance. These distal movements of the maxillary molars are favorable in Class

Meson Lai

2000-01-01

194

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.

Baum, W M

2001-01-01

195

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

196

Partial molal volumes and compressibilities of phosphoric acid and sodium phosphates in 0.725 molal NaCl at 25 °C.  

PubMed

The apparent molal volume V(?) and adiabatic compressibility ?(?) of H(3)PO(4), NaH(2)PO(4), Na(2)HPO(4), and Na(3)PO(4) have been determined from density and sound speed measurements in 0.725 m NaCl solutions at 25 °C. The partial molal volumes V(i)* and compressibilities ?(i)* have been determined by extrapolating the values of V(?) and ?(?) to infinite dilution in the NaCl media. The results have been compared to earlier measurements made on a number of electrolytes in NaCl media. The phosphate results showed correlations between the values of V(i)* and ?(i)* as found for other electrolytes. The values for the volume ?V(i) and compressibility ??(i) changes for the dissociation of H(3)PO(4) in 0.725 m NaCl have been calculated from the measurements. The calculated values of ?V(i) and compressibility ??(i) have been used to estimate the effect of pressure K(P)/K(0) on the dissociation of H(3)PO(4) in the oceans using RT ln[K(P)/K(0)] = -?V(i)P + 0.5??(i)P(2), where P is the applied pressure in bars. The results are in reasonable agreement with directly measured values. PMID:21141930

Millero, Frank J; Huang, Fen; Lo Surdo, Antonio; Vinokurova, Faina

2010-07-27

197

Excess molar volumes of binary mixtures of 2,2,2-trifluoroethanol with water, or acetone, or 1,4-difluorobenzene, or 4-fluorotoluene, or ?,?,?, trifluorotoluene or 1-alcohols at a temperature of 298.15 K and pressure of 101 kPa  

Microsoft Academic Search

Excess molar volumes VmE of binary mixtures of 2,2,2-trifluoroethanol with water, or acetone, or methanol, or ethanol, or 1-alcholos, or 1,4-difluorobenzene, or 4-fluorotoluene or ?,?,?-trifluorotoluene were measured in a vibrating tube densimeter at temperature 298.15 K and pressure of 101 kPa. The VmE extrema are: 1.540 cm3·mol?1 for (2,2,2-trifluoroethanol+1-heptanol); 1.452 cm3·mol?1 for (2,2,2-trifluoroethanol+1-hexanol); 1.238 cm3·mol?1 for (2,2,2-trifluoroethanol+1-butanol); 0.821 cm3·mol?1 for

Mounia Sassi; Zadjia Atik

2003-01-01

198

Liquid molar volumes of CH[sub 2]FCF[sub 3], CH[sub 3]CCIF[sub 2], and CH[sub 3]CHF[sub 2] and the mixtures CHF[sub 2]Cl + CH[sub 3]CCIF[sub 2] and CHF[sub 2]Cl + CH[sub 3]CHF[sub 2  

SciTech Connect

The liquid molar volumes of CH[sub 2]FCF[sub 3], CH[sub 3]CClF[sub 2], and CH[sub 3]CHF[sub 2] and the binary mixtures of CHClF[sub 2] + CH[sub 3]CClF[sub 2] and CHClF[sub 2] + CH[sub 3]CHF[sub 2] have been measured in the temperature range 260-320 K. Characteristic volumes for CH[sub 2]FCF[sub 3], CH[sub 3]CClF[sub 2], and CH[sub 3]CHF[sub 2] required for the Thomson-Brobst-Hankinson correlation have been determined. Interaction parameters for the equations of state have been determined from experimental data. In a comparative study, the deviation between experimental data and calculated data from three correlation methods is presented. The three methods are the liquid volume correlation according to Thomson-Brobst-Hankinson and the two equations of state according to Carnahan-Starling-de Santis and Lee-Kesler-Ploecker. The Thomson-Brobst-Hankinson correlation gives the least deviation of the three methods studied, for both pure components and mixtures. Of the two equations of state, the Carnahan-Starling-de Santis equation gives the best agreement with experimental data.

Stroem, K.H.U.; Gren, U.B. (Chalmers Univ. of Technology, Gothenburg (Sweden). Dept. of Chemical Engineering)

1993-01-01

199

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

200

"C"-shaped canal configuration of mandibular second permanent molar.  

PubMed

Roots of the second mandibular molar often fuse so the purpose of this investigation was to examine the appearance of "C"-shaped root canals and to classify different root canal types. A hundred and twelve randomly chosen second lower permanent molars-after extraction due to periodontal disease-were prepared and then analysed. Contrast liquid (methylene blue) was injected into prepared teeth. Each tooth was cut into slices to view the root canal morphology. Results of the analysis revealed fusion, either total or partial in 14 cases (12.5%). As a conclusion various appearances were classified into 5 types according to the fused canal shapes and the frequency of different types varied from 0.89%-6.25%. PMID:10097434

Sutalo, J; Simeon, P; Tarle, Z; Prskalo, K; Pevalek, J; Stanici?, T; Udovici?, M

1998-06-01

201

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.

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

2009-01-01

202

Maxillary first molar with two root canals.  

PubMed

Knowledge regarding the anatomic morphology of maxillary molars is absolutely essential for the success of endodontic treatment. The morphology of the permanent maxillary first molar has been reviewed extensively; however, the presence of two canals in a two-rooted maxillary first molar has rarely been reported in studies describing tooth and root canal anatomies. This case report presents a patient with a maxillary first molar with two roots and two root canals, who was referred to the Department of Endodontics, Tabriz University of Medical Sciences, Iran. PMID:23862051

Rahimi, Saeed; Ghasemi, Negin

2013-05-09

203

Molar development in common chimpanzees ( Pan troglodytes)  

Microsoft Academic Search

Numerous studies have reported on enamel and dentine development in hominoid molars, although little is known about intraspecific incremental feature variation. Furthermore, a recent histological study suggested that there is little or no time between age at chimpanzee crown completion and age at molar eruption, which is unlikely given that root growth is necessary for tooth eruption. The study presented

T. M. Smith; D. J. Reid; M. C. Dean; A. J. Olejniczak; L. B. Martin

2007-01-01

204

Lingual nerve paresthesia following third molar surgery  

Microsoft Academic Search

Lingual nerve anesthesia, paresthesia, and dysesthesia are possible side effects of third molar extraction. These unwanted complications are frequently disturbing to both the patient and practitioner. The incidence of lingual nerve damage following third molar surgery is more frequent than once thought. Six hundred questionnaires were sent to randomly selected Fellows of the American Association of Oral and Maxillofacial Surgeons

Allen F Fielding; Dominic P Rachiele; Gordon Frazier

1997-01-01

205

Partial Seizures  

MedlinePLUS

... are subdivided into simple partial seizures (in which consciousness or awareness is retained) and complex partial seizures (in which consciousness is impaired or lost). Partial seizures may spread ...

206

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.

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

207

Molar development in common chimpanzees (Pan troglodytes).  

PubMed

Numerous studies have reported on enamel and dentine development in hominoid molars, although little is known about intraspecific incremental feature variation. Furthermore, a recent histological study suggested that there is little or no time between age at chimpanzee crown completion and age at molar eruption, which is unlikely given that root growth is necessary for tooth eruption. The study presented here redefines growth standards for chimpanzee molar teeth and examines variation in incremental features. The periodicity of Retzius lines in a relatively large sample was found to be 6 or 7 days. The number of Retzius lines and cuspal enamel thickness both vary within a cusp type, among cusps, and among molars, resulting in marked variation in formation time. Daily secretion rate is consistent within analogous cuspal zones (inner, middle, and outer enamel) within and among cusp types and among molar types. Significantly increasing trends are found from inner to outer cuspal enamel (3 to 5 microns/day). Cuspal initiation and completion sequences also vary, although sequences for mandibular molar cusps are more consistent. Cusp-specific formation time ranges from approximately 2 to 3 years, increasing from M1 to M2, and often decreasing from M2 to M3. These times are intermediate between radiographic studies and a previous histological study, although both formation time within cusps and overlap between molars vary considerably. Cusp-specific (coronal) extension rates range from approximately 4 to 9 microns/day, and root extension rates in the first 5 mm of roots range from 3 to 9 microns/day. These rates are greater in M1 than in M2 or M3, and they are greater in mandibular molars than in respective maxillary molars. This significant enlargement of comparative data on nonhuman primate incremental development demonstrates that developmental variation among cusp and molar types should be considered during interpretations and comparisons of small samples of fossil hominins and hominoids. PMID:17084441

Smith, T M; Reid, D J; Dean, M C; Olejniczak, A J; Martin, L B

2006-09-23

208

Unilateral molar distalization with a modified slider.  

PubMed

Although there are numerous publications on bilateral non-compliance molar distalization appliances, there is limited information on problems such as asymmetrical unilateral Class II malocclusions. The aim of the present investigation was to examine the distalization of molars unilaterally in patients with a unilateral Class II molar relationship utilizing a Keles Slider, designed without a bite plane. Ten girls (mean age 13.94 +/- 2.13 years) and seven boys (mean age 13.12 +/- 1.51 years) comprised the study material. Following insertion of the appliance, the patients were seen monthly and the screw was reactivated every 2 months. After a super-Class I molar relationship was achieved, the appliance was removed and the molars were stabilized with a Nance appliance for 2 months before the second-phase of orthodontic treatment. The Nance appliance was maintained in the palate until the end of canine distalization. Lateral cephalometric radiographs were obtained before and immediately after insertion of the molar distalizer. The results showed that the maxillary first molars were distalized bodily on average by 2.85 mm. The maxillary first premolars moved forward bodily 2 mm and were extruded 2.03 mm. In all, 1.32 mm of protrusion, 1.12 mm of extrusion, and 1.79 degrees of proclination of the upper incisors were observed. The mandibular incisors and mandibular molars erupted 0.83 and 0.95 mm, respectively. The unilateral Keles Slider distalized molars successfully to a Class I molar relationship. PMID:16648210

Sayinsu, Korkmaz; Isik, Fulya; Allaf, Ferdi; Arun, Tülin

2006-04-28

209

How will mandibular third molar surgery affect mandibular second molar periodontal parameters?  

PubMed Central

Background: Several conflicting findings have been published in the previous literature regarding the effects of impacted third molar surgery on the periodontal parameters of the adjacent second molar; some authors have shown improvement of periodontal health distal to the adjacent second molar, whilst others have demonstrated loss of attachment level (AL) and reduction of alveolar bone height. The purpose of this study was to evaluate the changes in periodontal health parameters distal to the adjacent second molar following extraction of an impacted third molar. Materials and Methods: Out of 50 patients participated in the study, 42 patients completed the study. The mean age of the sample was 20.9 (range, 18-25) years. All teeth were mesioangular impacted mandibular third molars categorized at C1 class based on the Pell and Gregory classification. All surgeries were performed by one surgeon and the same surgeon recorded the pre-operative and post-operative measurements of probing depth (PD) and AL on the distobuccal aspect of the second molars. Data analysis were carried out with the SPSS software (version 19), using the paired-samples t-test and one sample t-test. Results: Surgical extraction of impacted mandibular third molar resulted in a significant increase of PD on the distobuccal aspect of the second molars, whereas AL was decreased significantly after surgery (P < 0.05). Conclusion: Unlike plenty of researches that have shown improvement of periodontal parameters of the second molar after extraction of impacted third molar, our study showed a significant increase in PD at the distal aspect of the second molar. Further follow-up on clinical and radiological parameters are required for more profound understanding of the long-term effects of third molar extraction on the periodontal parameters of the adjacent second molar.

Tabrizi, Reza; Arabion, Hamidreza; Gholami, Mehdi

2013-01-01

210

Partial hydatidiform mole in septate uterus.  

PubMed

Partial mole is a form of gestational trophoblastic disease that may be associated with serious medical complications and occasionally progresses to the second trimester of pregnancy. We present a case report of a partial mole diagnosed at 18 weeks of gestation in a septate uterus with molar placenta in one horn and a dead fetus in the other. PMID:19655383

Taori, Kishor; Sharbidre, Kedar G; Bopche, Sneha; Kulkarni, Bipin; Krishnan, Vijay; Disawal, Amit

2009-10-01

211

Mandibular first molar with three distal canals  

PubMed Central

With the increasing number of reports of aberrant root canal morphology, the clinician needs to be aware of the variable anatomy. Various case reports have been published with the finding of middle mesial canal in mandibular first molar, however finding of middle distal canal in distal root of mandibular first molar is rare. This case report describes root canal treatment of two rooted mandibular first molar with five root canals (three in distal and two in mesial root), and Sert and Bayirli Type XVIII canal configuration in distal root.

Jain, Shweta

2011-01-01

212

Fabrication and Evaluation of a Noncompliant Molar Distalizing Appliance: Bonded Molar Distalizer  

PubMed Central

Objective Attempts to treat class II malocclusions without extraction in non-compliant patients have led to utilization of intraoral molar distalizing appliances. The purpose of this study was to investigate dental and skeletal effects of Bonded Molar Distalizer (BMD) which is a simple molar distalizing appliance. Materials and Methods Sixteen patients (12 girls, four boys) with bilateral half-cusp class II molar relationship, erupted permanent second molars and normal or vertical growth pattern were selected for bilateral distalization of maxillary molars via BMD. The screws were activated every other day, alternately. Lateral cephalograms and study models were obtained before treatment and after 11 weeks activation of the appliance. Results Significant amounts of molar distalization, molar distal tipping and anchorage loss were observed. The mean maxillary first molar distal movement was 1.22±0.936 mm with a distal tipping of 2.97±3.74 degrees in 11 weeks. The rate of distal movement was 0.48 mm per month. Reciprocal mesial movement of the first premolars was 2.26±1.12 mm with a mesial tipping of 4.25±3.12 degrees. Maxillary incisors moved 3.55±1.46 mm and tipped 9.87±5.03 degrees mesially. Lower anterior face height (LAFH) decreased 1.28±1.36 mm. Conclusion BMD is appropriate for distalizing maxillary molars, especially in patients with critical LAFH, although significant amounts of anchorage loss occur using this appliance.

Sodagar, A.; Ahmad Akhoundi, M. S.; Rafighii, A.; Arab, S.

2011-01-01

213

Quantitative assessment of glucose metabolism in the vessel wall of abdominal aortic aneurysms: correlation with histology and role of partial volume correction.  

PubMed

Inflammatory-proteolytic processes in the vessel wall are essential in the pathophysiology of abdominal aortic aneurysm (AAA). It has been demonstrated that, (18)F-FDG-PET/CT may be useful for detection of pathological wall metabolism and therefore risk stratification. Quantification of the FDG-uptake in AAA wall is hampered by partial-volume (PV)-effects. For correction and accurate quantitative (18)F-FDG-uptake analysis we designed and validated a novel IDL-based software in correlation to phantom studies, histopathology and clinical presentation of AAA patients. For in vivo studies 23 patients with symptomatic and asymptomatic AAA underwent (18)F-FDG-PET/CT before surgery. In areas with (18)F-FDG-uptake the maximum and mean standardized uptake values in the vessel wall with (PVC-SUV(max), PVC-SUV(mean)) and without (SUV(max), SUV(mean)) PV-correction were determined. Results were correlated with clinical presentation, corresponding macrophage-infiltration and MMP-2- and -9-expression in surgical specimens. In patients, SUV(max), SUV(mean) as well as PVC-SUV(max) or PVC-SUV(mean) enabled a highly significant (p < 0.005) discrimination of symptomatic and asymptomatic AAA. Uncorrected and corrected SUVs showed comparable correlations with macrophage-infiltration and MMP-9 expression. No correlation of (18)F-FDG-uptake and MMP-2 was found. In vivo correlations of detected FDG-uptake with clinical and histological results showed comparable results for corrected and uncorrected SUVs. PV-correction is not mandatory for qualitative clinical assessment of glucose metabolism in the vessel wall of AAA-patients but may be necessary to establish quantitative cut off values to stratify patients for aneurysm repair. PMID:22772434

Reeps, Christian; Bundschuh, Ralph A; Pellisek, Jaroslav; Herz, Michael; van Marwick, Sandra; Schwaiger, Markus; Eckstein, Hans-Henning; Nekolla, Stephan G; Essler, Markus

2012-07-07

214

Canal complexity of a mandibular first molar  

PubMed Central

The endodontic treatment of a mandibular molar with aberrant canal configuration can be diagnostically and technically challenging. This case report presents the treatment of a mandibular first molar with five root canals, of which three were located in the mesial root. A third canal was found between the mesiobuccal and mesiolingual root canals. The morphological pattern of separate apical terminations of three mesial root canals with separate orifices, as manifested in this case, is a rare one.

Poorni, S; Kumar, RA; Indira, R

2009-01-01

215

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.

2013-01-01

216

Hemostasis and obliteration of mandibular arteriovenous malformation through direct hydroxyapatite cement injection into the molar cavity  

Microsoft Academic Search

A mandibular arteriovenous malformation (AVM) presented with massive molar socket bleeding and was emergently treated by tooth extraction and partial resection of the surrounding alveolar bone. To achieve hemostasis, the resultant cavity was filled with hydroxyapatite bone cement. Not only was hemostasis and alveolar reconstruction achieved, but follow-up angiography demonstrated venous outlet occlusion and retrograde AVM thrombosis requiring no further

Vicko Gluncic; Russell R Reid; Fuad M Baroody; Lawrence J Gottlieb; Sameer A Ansari

2010-01-01

217

Thermodynamic analysis of hydrogen production via partial oxidation of ethanol  

Microsoft Academic Search

Thermodynamic equilibrium of ethanol partial oxidation has been studied by Gibbs free energy minimization method for hydrogen production in the range of oxygen-to-ethanol molar ratio from 0 to 3, reaction temperature from 500 to 1400K, pressure from 1 to 20atm and nitrogen-to-ethanol molar ratio from 0 to 100. The optimal operation conditions were obtained, which are 1070–1200K, oxygen-to-ethanol molar ratio

Wenju Wang; Yaquan Wang

2008-01-01

218

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

219

A new approach in maxillary molar distalization: intraoral bodily molar distalizer.  

PubMed

The objectives of our study were to achieve bodily molar distalization, avoid distal tipping of molars, eliminate the need for patient cooperation (no headgear, no elastics, and no esthetic and social concern), and finally to minimize the treatment period and maximize the treatment efficiency. The study was carried out on 5 males and 10 females, a total of 15 patients. Mean age for the study group was 13.53 years. Dentally, all the patients had Class II molar relationship on both sides. The patients were in permanent dentition, second molars were erupted, and the lower dental arch was well aligned. Patients showed normal or sagittally directed growth pattern. Lateral cephalograms and study models were taken and analyzed before and after molar distalization. In the present study, in order to achieve maxillary molar distalization, a new intraoral appliance was developed. The intraoral bodily molar distalizer (IBMB) was composed of 2 parts: the anchorage unit and the distalizing unit. The anchorage unit was a wide Nance button, and the active unit consisted of distalizing springs. The springs had 2 components: the distalizer section of the spring applied a crown tipping force, while the uprighting section of the spring applied a root uprighting force on the first molars. A total of 230 g of distalizing force was used on both sides. After the distal movement of the first molars, the cephalometric results of 15 patients showed the following. Maxillary first molars were moved distally by an average of 5.23 mm (P <.001) without tipping or extrusion. Maxillary first premolars were moved 4.33 mm mesially (P <.001), tipped 2.73 degrees distally (P <.05), and extruded by 3.33 mm (P <.001). Maxillary central incisors were proclined by an average of 4.7 mm (P <.001) and tipped 6.73 degrees labially (P <.01). Model analysis showed that maxillary first molars were not rotated, and intermolar distance did not change after distal movement of molars. In conclusion, unlike most of the other molar distalization mechanics, this newly developed device achieved (1) bodily distal movement of maxillary molars and (2) eliminated dependence on patient cooperation and did not require headgear wear for molar root uprighting. PMID:10629518

Keles, A; Sayinsu, K

2000-01-01

220

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

221

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

PubMed

Kinetic parameters estimated from dynamic (18)F-fluorodeoxyglucose ((18)F-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 (18)F-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. PMID:24052021

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

2013-09-20

222

A new approach in maxillary molar distalization: Intraoral bodily molar distalizer  

Microsoft Academic Search

The objectives of our study were to achieve bodily molar distalization, avoid distal tipping of molars, eliminate the need for patient cooperation (no headgear, no elastics, and no esthetic and social concern), and finally to minimize the treatment period and maximize the treatment efficiency. The study was carried out on 5 males and 10 females, a total of 15 patients.

Ahmet Keles; Korkmaz Sayinsu

2000-01-01

223

Size dependence of molar absorption coefficients of CdSe semiconductor quantum rods.  

PubMed

Fundamental properties: The molar absorption coefficients of CdSe quantum rods are determined experimentally as a function of their dimensions (see figure). Far above the band gap a simple dependence on volume is seen. The behavior at the band gap manifests a concentration of oscillator strength with decreased diameter in agreement with strong quantum confinement behavior. PMID:19347917

Shaviv, Ehud; Salant, Asaf; Banin, Uri

2009-05-11

224

The partial molal volume of silicic acid in 0.725 M NaCl at 1°C determined by the neutralization of Na 2SiO 3  

NASA Astrophysics Data System (ADS)

The partial molal volume of silicic acid ( V¯(Si(OH) 4) ) in 0.725 M NaCl at 1°C was calculated from the measured volume change (? V¯n) due to the neutralization of anhydrous sodium metasilicate with HCl and the V¯(HCl) and V¯(NaCl) obtained from the literature. V¯(Si(OH) 4) = 59.0 cm 3mol - 1 , determined under experimental conditions of pH = 2.2, compares favorably with V¯(Si(OH) 4) = 58.9 cm 3 mol -1 calculated from the measured volume change due to the hydrolysis of the meta-silicate salt at pH = 11 and from the partial molal volume due to electrostriction ( V¯elect) of water by charged Si species present in the solution at the high pH. This agreement lends support to a semiempirical model for calculating V¯elect in developed by Millero (1969). V¯(NaOH) = - 5.45 cm 3 mol -1 in 0.725 M NaCl needed for this calculation was also determined in this work. The rate of polymerization of Si(OH) 4 at 1°C was monitored to insure that the monomer Si(OH) 4 was the main Si species present during the determination of V¯(Si(OH) 4) by neutralization of the alkali silicate. V¯(Si(OH) 4) determined in this study compares favorably with the value calculated from high pressure solubility measurements.

Hershey, J. Peter; Duedall, Iver W.

1983-11-01

225

Molar and molecular views of choice.  

PubMed

The molar and molecular views of behavior are not different theories or levels of analysis; they are different paradigms. The molecular paradigm views behavior as composed of discrete units (responses) occurring at moments in time and strung together in chains to make up complex performances. The discrete pieces are held together as a result of association by contiguity. The molecular view has a long history both in early thought about reflexes and in associationism, and, although it was helpful to getting a science of behavior started, it has outlived its usefulness. The molar view stems from a conviction that behavior is continuous, as argued by John Dewey, Gestalt psychologists, Karl Lashley, and others. The molar paradigm views behavior as inherently extended in time and composed of activities that have integrated parts. In the molar paradigm, activities vary in their scale of organization--i.e., as to whether they are local or extended--and behavior may be controlled sometimes by short-term relations and sometimes by long-term relations. Applied to choice, the molar paradigm rests on two simple principles: (a) all behavior constitutes choice; and (b) all activities take time. Equivalence between choice and behavior occurs because every situation contains more than one alternative activity. The principle that behavior takes time refers not simply to any notion of response duration, but to the necessity that identifying one action or another requires a sample extended in time. The molecular paradigm's momentary responses are inferred from extended samples in retrospect. In this sense, momentary responses constitute abstractions, whereas extended activities constitute concrete particulars. Explanations conceived within the molecular paradigm invariably involve hypothetical constructs, because they require causes to be contiguous with responses. Explanations conceived within the molar paradigm retain direct contact with observable variables. PMID:15157981

Baum, William M

2004-06-30

226

Characteristics of Women with Recurrent Molar Pregnancies  

Microsoft Academic Search

Objectives. The aim of this study was to examine the incidence and characteristics of women who develop a second molar pregnancy after a previous episode of gestational trophoblastic disease.Methods. A retrospective analysis was carried out on completed registration forms from referring hospitals in the North of England to the Sheffield Trophoblastic Screening Service over a 13-year period. All cases of

P. C. Lorigan; S. Sharma; N. Bright; R. E. Coleman; B. W. Hancock

2000-01-01

227

Mass versus molar doses, similarities and differences.  

PubMed

Generally, they are two systems expressing the amounts of active substance in a given drug product, i.e. mass and molar dose. Currently, the dose system based on the mass is widely used in which doses are expressed in grams or milligrams. On the other hand, the molar dose system is in direct relation to the number of molecules. Hence, the objective of this work was to compare both systems in order to find their advantages and disadvantages. Active substances belonging to the groups of antibiotics, nootropic agents, beta-blockers, vitamins, GABA-analog, COX-2 inhibitors, calcium channel antagonists, benzodiazepine receptor agonists, lipid-modifying agents (fibrates), non-steroidal anti-inflammatory drugs (profens), estrogens, neuroleptics, analgesics and benzodiazepines were considered. Moreover, products containing two active substances were also taken into account. These are mixtures of hydrochlorothiazide with active substances influencing the renin-angiotensin system and combined oral contraceptives. For each active substance, belonging to the groups mentioned above molar doses were calculated from mass doses and molar mass. Hence, groups of drugs with a single active substance, drugs with similar pharmacological activities, pharmaceutical alternatives, and drugs with a single active ingredient manufactured in different doses were compared in order to find which dose system describes more adequately differences between and within the groups mentioned above. Comparisons were supported by a number of equations, which theoretically justify the data, and relationships derived from calculations. PMID:19069248

Chmielewska, A; Lamparczyk, H

2008-11-01

228

Uncertainty assessment of Si molar mass measurements  

NASA Astrophysics Data System (ADS)

The uncertainty of the Si molar mass measurement is theoretically investigated by means of a two-isotope model, with particular emphasis to the role of this measurement in the determination of the Avogadro constant. This model allows an explicit calibration formula to be given and propagation of error analysis to be made. It also shows that calibration cannot correct for non-linearity.

Mana, G.; Massa, E.; Valkiers, S.; Willenberg, G.-D.

2010-01-01

229

Endodontic therapy on the mandibular second molar: easiest to treat of the difficult, molar teeth.  

PubMed

Molar teeth present more problems during endodontic therapy than do bicuspid or anterior teeth. The major reasons for this are that molars can have complicated canal systems with unexpectedly large numbers of teeth with four canals, and they often have quite curved canals, which are more difficult to prepare and fill. The mandibular second molar generally is the easiest of these difficult teeth to treat, but they do have some areas of complication, too. The mesial root almost always has two--not one--canals and a rarely described condition, the C-shaped canal system, may be present. PMID:7987904

Weine, F S

1994-09-01

230

18F-fluorocholine PET-guided target volume delineation techniques for partial prostate re-irradiation in local recurrent prostate cancer  

Microsoft Academic Search

Background and purposeWe evaluate the contribution of 18F-choline PET\\/CT in the delineation of gross tumour volume (GTV) in local recurrent prostate cancer after initial irradiation using various PET image segmentation techniques.

Hui Wang; Hansjörg Vees; Raymond Miralbell; Michael Wissmeyer; Charles Steiner; Osman Ratib; Srinivasan Senthamizhchelvan; Habib Zaidi

2009-01-01

231

Partial specific volume of poly[2,5-bis(carbomethoxy)terephthaloyl chloride-co-3,3-bis(4-aminophenyl)phthalide  

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.

232

[Partial tonsillectomy].  

PubMed

The feasibility of partial tonsillectomy was reviewed. Compared with total tonsillectomy, partial tonsillectomy has the advantages of less postoperative pain, lower postoperative bleeding rate and faster recovery. Partial tonsillectomy has a potential for tonsil regrowth and its efficacy in treating sleep-disordered breathing in children is still controversial. PMID:24015642

Guo, Pengfei; Li, Jinrang

2013-06-01

233

Human dental age estimation combining third molar(s) development and tooth morphological age predictors.  

PubMed

In the subadult age group, third molar development, as well as age-related morphological tooth information can be observed on panoramic radiographs. The aim of present study was to combine, in subadults, panoramic radiographic data based on developmental stages of third molar(s) and morphological measurements from permanent teeth, in order to evaluate its added age-predicting performances. In the age range between 15 and 23 years, 25 gender-specific radiographs were collected within each age category of 1 year. Third molar development was classified and registered according the 10-point staging and scoring technique proposed by Gleiser and Hunt (1955), modified by Köhler (1994). The Kvaal (1995) measuring technique was applied on the indicated teeth from the individuals' left side. Linear regression models with age as response and third molar-scored stages as explanatory variables were developed, and morphological measurements from permanent teeth were added. From the models, determination coefficients (R (2)) and root-mean-square errors (RMSE) were calculated. Maximal-added age information was reported as a 6 % R² increase and a 0.10-year decrease of RMSE. Forensic dental age estimations on panoramic radiographic data in the subadult group (15-23 year) should only be based on third molar development. PMID:22885953

Thevissen, P W; Galiti, D; Willems, G

2012-08-12

234

Therapeutic choices in the molar region.  

PubMed

Treatment of the damaged molar often presents a set of challenges unique to the posterior dentition. Traditional dental treatments continue to be refined to improve the prognosis when treating the posterior dentition. Daily treatment-planning decisions include whether to treat with conventional dental or implant therapeutic approaches, and involve consideration of local host factors as well as limitations in specific therapeutic approaches. This article will review some of the factors to consider in these treatment-planning decisions. PMID:12041803

Ducar, John P; Tsutsui, Fred; Merin, Robert L

2002-05-01

235

In vivo quantification of pulmonary inflammation in relation to emphysema severity via partial volume corrected (18)F-FDG-PET using computer-assisted analysis of diagnostic chest CT.  

PubMed

Our aim was to quantify the degree of pulmonary inflammation associated with centrilobular emphysema using fluoro-18-2-fluoro-2-deoxy-D-glucose positron emission tomography ((18)F-FDG-PET) and diagnostic unenhanced computed tomography (CT) based image segmentation and partial volume correction. Forty-nine subjects, with variable amounts of centrilobular emphysema, who had prior diagnostic unenhanced chest CT and either (18)F-FDG-PET or (18)F-FDG-PET/CT were selected. Lung parenchymal volume (L) (in cm³) excluding large and small pulmonary vessels, emphysema volume (E) (in cm³) based on a -910HU threshold, fraction of lung emphysema (F=E/L), and mean attenuation (HU) of non-emphysematous lung parenchyma (A) were calculated from CT images using the image analysis software 3DVIEWNIX. Lung uncorrected maximum SUV (USUVmax) was measured manually from PET images on a dedicated workstation. A first level of partial volume correction (PVC) of lung SUVmax to account for presence and degree of macroscopic emphysematous air space was calculated as CSUVmax=USUVmax/(1-F). A second level of PVC of non-emphysematous lung SUVmax to account for the mixture of air and lung parenchyma at the microscopic level was then estimated as CCSUVmax=CSUVmax/(A+1000/1040), assuming that air is -1000HU in attenuation and gasless lung parenchyma is 40HU in attenuation. The correlation of F with USUVmax, CSUVmax, CCSUVmax, % change between CSUVmax and USUVmax (%UC), and % change between CCSUVmax and USUVmax (%UCC) were then tested. The results showed that USUVmax was not significantly correlated with F (r=-.0973, P=0.34). CSUVmax (r=0.4660, P<0.0001) and CCSUVmax were significantly positively correlated with F (r=0.5479, P<0.0001), as were %UC (r=0.9383, P<0.0001) and %UCC (r=0.9369, P<0.0001). In conclusion, the degree of pulmonary inflammation increases with emphysema severity based on (18)F-FDG-PET or (18)F-FDG-PET/CT assessment, but is only detectable when (18)F-FDG uptake is corrected for the partial volume effect based on data provided from diagnostic chest CT images. These results support the notion that pulmonary inflammation plays an important role in the pathophysiology of emphysema. This novel image analysis approach has great potential for practical, accurate, and precise combined structural-functional PET quantification of pulmonary inflammation in patients with emphysema or other pulmonary conditions, although further validation and refinement will be required. PMID:23529388

Torigian, Drew A; Dam, Vincent; Chen, Xinjian; Saboury, Babak; Udupa, Jayaram K; Rashid, Arif; Moghadam-Kia, Siamak; Alavi, Abass

2013-03-26

236

Enzyme Molar Fractions: A Powerful Tool for Understanding Enzyme Kinetics.  

ERIC Educational Resources Information Center

|Deduces the relationship between reduced velocity and molar fractions for productive enzyme complexes; obtains the mathematical expression of molar fractions for an enzyme with two specific binding sites per molecule; and proposes a useful plot to follow the dependence of enzyme molar fractions with the concentration of one of its ligands. (JN)|

Serra, Juan L.; And Others

1986-01-01

237

Radiographic evaluation of mandibular third molar eruption space  

Microsoft Academic Search

Objective. The purpose of this study was to investigate variables in third molar and arch dimensions among subjects with impacted and erupted mandibular third molars. Study Design. Standardized panoramic radiographs were taken for 134 subjects (60 males and 74 females with 213 third molars) with an average age of 19.8 years. For the impacted group, only those who had mesioangular

Faiez N. Hattab; Elham S. J. Abu Alhaija

1999-01-01

238

[Ectopic molar tooth in the maxillary sinus].  

PubMed

The development of intranasal ectopic teeth is rare. Although they are more commonly seen in the palate and maxillary sinus, they can also be found in the mandibular condyle, coronoid process, and nasal cavity. A 30-year-old male patient presented with a complaint of headache. Computed tomography of the paranasal sinuses showed a bony mass in the right maxillary sinus wall, 1 cm in size. He did not have any history of maxillofacial trauma or operation. The mass was removed via a Caldwell-Luc procedure. It looked like a tooth. Histopathologic diagnosis was made as ectopic molar tooth. The patient was asymptomatic two weeks after the operation. PMID:18187979

Altun, Hüseyin; Teker, Ay?enur Meriç; Ceran, Murat; Gedikli, Orhan

2007-01-01

239

Preemptive analgesia in third molar impaction surgery  

PubMed Central

Introduction: We have evaluated efficacy of diclofenac sodium as pre-emptive analgesia agent in a prospective triple blind placebo controlled randomized clinical trial in a patients undergoing third molar impaction surgery. Materials and Methods: Randomization of groups was done by randomization software and two groups were constituted one group receiving placebo pre operatively and then the drug for next five days while the other group was given diclofenac sodium pre operatively and then for five days. Results: Results were achieved with help of measurement of outcome variables like postoperative tenderness, swelling and trismus on a visual analogous scale (VAS) and other personalized scale. Collected data shows that there is a significant reduction in the score of postop tenderness in experimental group (P = 0.00), while there is a minimal difference between score of postoperative swelling and tenderness (P > 0.04). Conclusion: So, we can conclude that use of diclofenac sodium as a preemptive analgesic agent is beneficial for better pain control in third molar impaction surgery.

Shah, Rakesh; Mahajan, Amit; Shah, Navin; Dadhania, Ashish P.

2012-01-01

240

Electrical Insulating and Heat-Resistive Properties of PDMS-TEOS Hybrid with Different Molar Ratio of TEOS to PDMS  

Microsoft Academic Search

The hybrids prepared from polydimethylsiloxane (PDMS) and tetraethoxysilane (TEOS) have been well known to be rubbery hybrid materials. In this report, the authors have investigated the electrical insulating and heat resistive properties of the hybrids by changing the molar ratio of TEOS to PDMS. The electrical insulating properties are evaluated by volume resistivity and AC breakdown strength at room temperature.

Makoto Sugiura; Fumitoshi Imasato; Atsushi Ohno; Yusuke Aoki; Shuhei Nakamura; Tetsushi Okamoto; Takuya Shindou

2007-01-01

241

Measurement and Modeling of Resistivity as a Microscale Tool to Quantify the Volume Fraction of Lenticular (alpha)' Particles in a Partially Transformed (delta)-phase Pu-Ga Matrix  

SciTech Connect

We have measured and modeled the change in electrical resistivity due to partial transformation to the martensitic {alpha}{prime}-phase in a {delta}-phase Pu-Ga matrix. The primary objective is to relate the change in resistance, measured with a 4-probe technique during the transformation, to the volume fraction of the {alpha}{prime} phase created in the microstructure. Analysis by finite element methods suggests that considerable differences in the resistivity may be anticipated depending on the orientational and morphological configurations of the {alpha}{prime} particles. Finite element analysis of the computed resistance of an assembly of lenticular shaped particles indicates that series resistor or parallel resistor approximations are inaccurate and can lead to an underestimation of the predicted amount of {alpha}{prime} in the sample by 15% or more. Comparison of the resistivity of a simulated network of partially transformed grains or portions of grains suggests that a correction to the measured resistivity allows quantification of the amount of {alpha}{prime} phase in the microstructure with minimal consideration of how the {alpha}{prime} morphology may evolve. It is found that the average of the series and parallel resistor approximations provide the most accurate relationship between the measured resistivity and the amount of {alpha}{prime} phase. The methods described here are applicable to any evolving two-phase microstructure in which the resistance difference between the two phases is measurable.

Haslam, J J; Wall, M A; Johnson, D L; Mayhall, D J; Schwartz, A J

2005-07-13

242

Autotransplantation of Mandibular Third Molar: A Case Report  

PubMed Central

Autogenous transplantation is a feasible, fast, and economical option for the treatment of nonsalvageable teeth when a suitable donor tooth is available. This paper presents successful autotransplantation of a mature mandibular left third molar (38) without anatomical variances is used to replace a mandibular left second molar (37). The mandibular second molar was nonrestorable due to extensive root caries and resorption of distal root. After extraction of mandibular second and third molars, root canal therapy was done for the third molar extraorally, and the tooth was reimplanted into the extracted socket of second molar site. After one year, clinical and radiographic examination revealed satisfactory outcome with no signs or symptoms suggestive of pathology. In selected cases, autogenous tooth transplantation, even after complete root formation of the donor tooth, may be considered as a practical treatment alternative to conventional prosthetic rehabilitation or implant treatment.

Ravi kumar, Pabbati; Jyothi, Mandava; Sirisha, Kantheti; Racca, Khushboo; Uma, Chalasani

2012-01-01

243

Displacement of maxillary third molar into the lateral pharyngeal space.  

PubMed

Iatrogenic tooth displacement is a rare complication during extraction of impacted molars, but displacement of a maxillary third molar into the maxillary sinus, infratemporal fossa, buccal space, pterygomandibular space, and lateral pharyngeal space has been reported. Currently, 6 published reports describe third molar displacement into the lateral pharyngeal space, only 1 of which involved the loss of a maxillary third molar into this area, which occurred after an attempted self-extraction by the patient. There have been no reported cases of iatrogenic displacement of the maxillary third molar during an extraction procedure. This article describes the recovery, under general anesthesia, of a maxillary third molar from the lateral pharyngeal space after an iatrogenic displacement. PMID:23890786

Lee, Doksa; Ishii, Syoichiro; Yakushiji, Noboru

2013-07-24

244

Excess molar volumes of ternary mixtures of [x{sub 1}CH{sub 3}CH{sub 2}COOCH{sub 2}CH{sub 3} + x{sub 2}CH{sub 3}(CH{sub 2}){sub 4}CH{sub 3} + (1 {minus} x{sub 1} {minus} x{sub 2})CH{sub 3}(CH{sub 2}){sub 6}OH or CH{sub 3}(CH{sub 2}){sub 7}OH] at the temperature of 298.15 K  

SciTech Connect

Excess molar volumes at the temperature 298.15 K were measured for the ternary systems [x{sub 1}ethyl propanoate + x{sub 2}hexane + (1 {minus} x{sub 1} {minus} x{sub 2})heptan-1-ol or (1 {minus} x{sub 1} {minus} x{sub 2})octan-1-ol] and for binary mixtures [x{sub 1}ethyl propanoate + (1 {minus} x{sub 1})n-hexane], [x{sub 1}ethyl propanoate + (1 {minus} x{sub 1})heptan-1-ol], [x{sub 1}n-hexane + (1 {minus} x{sub 1})heptan-1-ol], [x{sub 1}ethyl propanoate + (1 {minus} x{sub 1})octan-1-ol], and [x{sub 1}n-hexane + (1 {minus} x{sub 1})octan-1-ol]. Excess molar volumes were determined using a densimeter Anton Paar DMA 60/602. The experimental values were compared with the results obtained with some empirical methods for the estimation of ternary properties from binary results.

Jimenez, E.; Franjo, C.; Segade, L. [Univ. da Coruna (Spain); Legido, J.L. [Univ. de Vigo (Spain); Paz Andrade, M.I. [Univ. de Santiago (Spain)

1997-03-01

245

New perspectives on chimpanzee and human molar crown development  

Microsoft Academic Search

\\u000a Previous histological studies of small samples of chimpanzee and human molars suggested similarities in crown formation time,\\u000a which is surprising given substantial life history differences. As part of an on-going study of hominoid molar development,\\u000a we report on the largest-known sample of chimpanzee and human molars, including re-evaluation of previously examined histological\\u000a sections. Variation of incremental features within and between

T. M. Smith; D. J. Reid; M. C. Dean; A. J. Olejniczak; L. B. Martin

246

Evaluation of an intraoral maxillary molar distalization technique.  

PubMed

The purpose of this study was to determine the effects of the pendulum appliance on distalization of maxillary molars and the reciprocal effects on the anchor premolars and maxillary incisors. Initial and follow-up cephalometric radiographs were obtained on 41 subjects (26 girls and 15 boys) who were treated with the pendulum appliance for bilateral distalization of the maxillary first molar teeth, for correction of the Class II molar relationship or for gaining space in the maxillary arch. Dental casts were available on 31 patients. Dental, skeletal, and soft tissue changes were determined. The mean maxillary first molar distalization was 3.37 mm, with a distal tipping of 8.36 degrees. The mean reciprocal mesial movement of the first premolar was 2.55 mm, with a mesial tipping of 1.29 degrees. The maxillary first molar position intruded 0.1 mm, whereas the first premolar extruded 1.7 mm. The transverse width between the mesiobuccal cusps of the first molars increased 1.40 mm. The maxillary second molars were also distalized 2.27 mm, tipped distally 11.99 degrees, and moved buccally 2.33 mm. The effect of distalization on the maxillary third molars was extremely variable. The eruption of maxillary second molars had minimal effect on distalization of first molars. The lower anterior face height increased by 2.79 mm. This increase was greater in patients with higher Frankfort-mandibular plane angle measurements. The pendulum appliance is an effective and reliable method for distalizing maxillary molars, provided the anchor unit is adequately reinforced. Its major advantages are minimal dependence on patient compliance, ease of fabrication, one-time activation, adjustment of the springs if necessary to correct minor transverse and vertical molar positions, and patient-acceptance. PMID:8972811

Ghosh, J; Nanda, R S

1996-12-01

247

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

2013-08-09

248

Applications of tissue heterogeneity corrections and biologically effective dose volume histograms in assessing the doses for accelerated partial breast irradiation using an electronic brachytherapy source  

NASA Astrophysics Data System (ADS)

A low-energy electronic brachytherapy source (EBS), the model S700 Axxent™ x-ray device developed by Xoft Inc., has been used in high dose rate (HDR) intracavitary accelerated partial breast irradiation (APBI) as an alternative to an Ir-192 source. The prescription dose and delivery schema of the electronic brachytherapy APBI plan are the same as the Ir-192 plan. However, due to its lower mean energy than the Ir-192 source, an EBS plan has dosimetric and biological features different from an Ir-192 source plan. Current brachytherapy treatment planning methods may have large errors in treatment outcome prediction for an EBS plan. Two main factors contribute to the errors: the dosimetric influence of tissue heterogeneities and the enhancement of relative biological effectiveness (RBE) of electronic brachytherapy. This study quantified the effects of these two factors and revisited the plan quality of electronic brachytherapy APBI. The influence of tissue heterogeneities is studied by a Monte Carlo method and heterogeneous 'virtual patient' phantoms created from CT images and structure contours; the effect of RBE enhancement in the treatment outcome was estimated by biologically effective dose (BED) distribution. Ten electronic brachytherapy APBI cases were studied. The results showed that, for electronic brachytherapy cases, tissue heterogeneities and patient boundary effect decreased dose to the target and skin but increased dose to the bones. On average, the target dose coverage PTV V100 reduced from 95.0% in water phantoms (planned) to only 66.7% in virtual patient phantoms (actual). The actual maximum dose to the ribs is 3.3 times higher than the planned dose; the actual mean dose to the ipsilateral breast and maximum dose to the skin were reduced by 22% and 17%, respectively. Combining the effect of tissue heterogeneities and RBE enhancement, BED coverage of the target was 89.9% in virtual patient phantoms with RBE enhancement (actual BED) as compared to 95.2% in water phantoms without RBE enhancement (planned BED). About 10% increase in the source output is required to raise BED PTV V100 to 95%. As a conclusion, the composite effect of dose reduction in the target due to heterogeneities and RBE enhancement results in a net effect of 5.3% target BED coverage loss for electronic brachytherapy. Therefore, it is suggested that about 10% increase in the source output may be necessary to achieve sufficient target coverage higher than 95%.

Shi, Chengyu; Guo, Bingqi; Cheng, Chih-Yao; Eng, Tony; Papanikolaou, Nikos

2010-09-01

249

Surface protection for newly erupting first molars.  

PubMed

The objective of this study was to compare the retention of GC Fuji Triage glass-ionomer to Delton FS+, a resin-based sealant on saliva-contaminated enamel surfaces. Seventy-two extracted noncarious human permanent molars were divided into 3 groups for sealing using Triage (T), Delton FS+ with Prime & Bond NT (DP), and Delton FS+ (D) alone. After prophylaxis with pumice, Groups D and DP were etched with 38% H3PO4 for 30 seconds. Group T was treated with Cavity Conditioner. A single drop of natural saliva was applied to the occlusal surface with a microbrush. Sealants were then placed according to the manufacturer's directions. Bonding agent was applied and light-cured for 20 seconds before the application of Delton for the DP group. All sealants covered the entire occlusal surface. The groups were further subdivided into 3 time-evaluation intervals: 6 months, 1 year, and 2 years (8 samples each). They were thermocycled (5 degrees C to 55 degrees C, 1 minute dwell time) at 250, 500, and 1,000 cycles, respectively. After each thermocycling period, they were subjected to toothbrush abrasion for their respective times (3,000 strokes, 6,000 strokes, and 12,000 strokes). All samples were finally observed clinically for retention of sealant. Samples with clinically visible loss of material were further evaluated under a scanning electron microscope (SEM) to verify the loss in the pits and fissures. After the first thermocycling period, 5 of the 24 samples (21%) of Group D revealed complete visual loss of sealant. There was no further loss after the second period. After the third period of thermocycling, an additional 4 samples revealed complete visible loss of the sealant material from Group D (total 37.5% failure). SEM evaluation verified the complete loss of sealants. Groups T and DP showed 100% retention after the entire period of aging and toothbrush-abrasion. Both of these groups demonstrated similar wear rates. Therefore, concerning fluoride release and simpler technique, especially with newly-erupting molars, Triage has advantages. PMID:16454015

Antonson, Sibel A; Wanuck, Jason; Antonson, Donald E

2006-01-01

250

Sensory nerve impairment following mandibular third molar surgery  

Microsoft Academic Search

Purpose: This prospective study reports the rate and factors influencing sensory impairment of the inferior alveolar and lingual nerves after the removal of impacted mandibular third molars under local anesthesia. Patients and Methods: There were 741 patients with 741 mandibular third molars removed under local anesthesia during a 3-year period from 1994 to 1997. Standardized data collection included the patient's

Anwar B Bataineh

2001-01-01

251

Molar Intercuspal Dimensions: Genetic Input to Phenotypic Variation  

Microsoft Academic Search

Molecular studies indicate that epigenetic events are important in determining how the internal enamel epithelium folds during odontogenesis. Since this process of folding leads to the subsequent arrangement of cusps on molar teeth, we hypothesized that intercuspal distances of human molar teeth would display greater phenotypic variation but lower heritabilities than overall crown diameters. Intercuspal distances and maximum crown diameters

G. Townsend; L. Richards; T. Hughes

2003-01-01

252

Molecular Characterization of Human Impacted Third Molars: Diversification of Compartments  

Microsoft Academic Search

To gain more insight into the development of human teeth, we characterized different compartments of impacted third molars at two developmental stages by assessing expression levels of a set of genes. We considered genes known to be essential for the development of teeth and ectomesenchyme as well as genes covering characteristic features of stemness. Molars were divided into the operculum,

B. Schoenebeck; H. J. Hartschen; M. Schindel; O. Degistirici; J. Siemonsmeier; W. Goetz; M. Thie

2009-01-01

253

Orthodontic band retention on primary molar stainless steel crowns  

Microsoft Academic Search

The retention of orthodontic bands cemented on primary molar stainless steel crowns (SSC) was studied in vitro. Unitek maxillary and mandibular 1st and 2nd primary molar SSC were fitted with one of four commonly used orthodontic bands (Unitek regular, Unitek narrow, Rocky Mountain, or custom bands made from SSC) using glass ionomer cement. The cemented samples were tested for their

Randy L. Beemer; Jack L. Ferracane; Harold E. Howard

1993-01-01

254

Root canal morphology of human maxillary and mandibular third molars.  

PubMed

The anatomy of third molars has been described as unpredictable. However restorative, prosthetic, and orthodontic considerations often require endodontic treatment of third molars in order for them to be retained as functional components of the dental arch. The purpose of this study was to investigate and characterize the anatomy of maxillary and mandibular third molars. One hundred fifty maxillary and 150 mandibular extracted third molars were vacuum-injected with dye, decalcified, and made transparent. The anatomy of the root canal system was then recorded. Seventeen percent of mandibular molars had one root (40% of which contained two canals), 77% had two roots, 5% had three roots, and 1% had four roots. Teeth with two roots exhibited highly variable canal morphology, containing from one to six canals, including 2.2% that were "C-shaped." Fifteen percent of maxillary molars had one root, 32% had two roots, 45% had three roots, and 7% had four roots. Teeth with one root demonstrated the most unusual morphology, with the number of canals varying from one to six. An in vivo study of the canal morphology of treated third molars is suggested to provide the practitioner with an understanding of the clinical implications of third molar root anatomy. PMID:11469300

Sidow, S J; West, L A; Liewehr, F R; Loushine, R J

2000-11-01

255

Analysis of rapid maxillary molar distal movement without patient cooperation  

Microsoft Academic Search

The purpose of this investigation was to evaluate the treatment effects of an intraoral appliance used for rapid distal movement of the maxillary molars. The appliance studied, the Jones jig, is designed to deliver a distalizing force to the maxillary molar against an intraoral anchorage unit thereby eliminating the need for patient compliance. A retrospective study was performed comparing before

Mark E. Runge; John T. Martin; Firas Bukai

1999-01-01

256

Relative molar response factors for thermal conductivity detectors  

PubMed

This paper describes an investigation into the universal nature of relative molar response factors for thermal conductivity detectors. Relative molar response factors are measured on multiple gas chromatographs equipped with thermal conductivity detectors, and the values are compared with values in the literature. As was observed previously, relative molar responses obtained on a single instrument for a homologous series vary linearly with respect to the number of carbon atoms in the hydrocarbon chain. However, significant differences are observed for the slope of this line depending on the instrument studied. This contradicts previous literature results that demonstrated an indepedence of the relative molar response with regard to the detector. The current results show that the calibration of thermal conductivity detectors using literature values for relative molar response factors could produce significant errors in the concentrations measured by the laboratory chromatograph. PMID:10702921

Gislason; Wharry

2000-03-01

257

Extraction of maxillary first molars improves second and third molar inclinations in Class II Division 1 malocclusion  

Microsoft Academic Search

INTRODUCTION: The aim of this study was to assess the changes in inclination of the maxillary second (M2) and third (M3) molars after orthodontic treatment of Class II Division 1 malocclusion with extraction of maxillary first molars. METHODS: Two groups of subjects were studied. The experimental group consisted of 37 subjects, 18 boys and 19 girls (mean age, 13.2 +\\/-

Christos Livas; Demetrios J. Halazonetis; Johan Willem Booij; Christos Katsaros

2011-01-01

258

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

259

Are referred inaccessible human primary molar teeth really inaccessible?  

PubMed

Despite a body of compelling evidence pertaining to the root canal accessibility of primary teeth, the number of referrals for inaccessibility of primary molars is considerable. The aim of the present study was to evaluate the prevalence of true and false primary molar inaccessibility among subjects who had been referred by general and pediatric dentists. We examined 199 primary molars in 156 patients (87 males, 69 females) aged 3-7 years who were referred by 215 general and 35 pediatric dentists. Problems related to inaccessibility were recorded for each tooth and any individual canal. One hundred seventy-five inaccessible teeth (87.9%) were successfully rehabilitated to accessible status (P < 0.001). The most frequent cause of inaccessibility was an inappropriate access cavity (42.3%), followed by difficult canals (32.6%) and orifice calcification (25.2%). The tooth most frequently reported as inaccessible was the maxillary first molar (40.2%), and that least frequently reported was the mandibular second molar (11.6%). The distobuccal canal of the maxillary first molar and the mesiolingual canal of the mandibular first molar were the most commonly inaccessible canals (P < 0.001). Only 1 out of 8 teeth referred as inaccessible was truly inaccessible. It seems that root canal inaccessibility is mostly attributable to lack of expertise among individual practitioners. PMID:23748457

Asl Aminabadi, Naser; Sighari Deljavan, Alireza; Samiei, Mohammad; Jamali, Zahra

2013-01-01

260

Solvation molar enthalpies and heat capacities of n-alkanes and n-alkylbenzenes on stationary phases of wide-ranging polarity.  

PubMed

A comparison of the most usual gas chromatographic methods for the calculation of partial molar enthalpies of solvation (?(sol)H(o)) has been carried out. Those methods based on the fitting of lnV(g) or ln(k/T) vs. 1/T and ln(k/T) vs. (1/T and the temperature arrangement, T(a)) are the most adequate ones for obtaining ?(sol)H(o) values. However, the latter is the only reliable option for ?(sol)H(o) estimation when commercial WCOT capillary columns are used, since in this case the estimation of some variables involved in the V(g) determination is less accurate or even impossible. Consequently, in this paper, ?(sol)H(o) obtained from ln(k/T) vs. (1/T+T(a)) fitting at 373.15 and 298.15K for n-alkanes and n-alkylbenzenes on 12 commercial capillary columns coated with stationary phases covering the 203-3608 McReynolds polarity range are reported. Moreover, molar heat capacities of solvation at constant pressure (?(sol)C(p)(o)) have also been calculated using this method. A clear influence on ?(sol)H(o) of the type and content of the substitution group in the stationary phase was observed. In addition, a linear relationship of ?(sol)C(p)(o) with the van der Waals volume of the n-alkanes and the temperature gradient of density of the stationary phase was found. The effect of the size of the hydrocarbon on both thermodynamic variables was also investigated. PMID:21040924

Lebrón-Aguilar, Rosa; Quintanilla-López, Jesús Eduardo; Santiuste, José María

2010-10-30

261

Complex Partial Seizures  

MedlinePLUS

Complex Partial Seizures You are here: Home About Epilepsy Seizures Partial Seizures Complex Partial Seizures Email Print Twitter Facebook MySpace Delicous ... Complex Partial Seizures ] First Aid for Complex Partial Seizures Do not restrain the person. Remove dangerous objects ...

262

Strongly Composition-Dependent Partial Molar Compressibility of Water in Silicate Glasses  

Microsoft Academic Search

Water and other volatiles have long been known to play a fundamental role in igneous processes, yet their influence on the physical properties of melts are still not well enough understood. Of particular interest is the density contrast between liquid and solid phases, which facilitates melt extraction and migration. Owing to its low molecular weight, dissolved water must decrease magma

A. G. Whittington; P. Richet; A. Polian

2010-01-01

263

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

264

Odontoblast response to cavity preparation with Er:YAG laser in rat molars: an immunohistochemical study.  

PubMed

This study aimed to examine the dynamics of odontoblast-lineage cells following cavity preparation with erbium:yttrium-aluminum-garnet (Er:YAG) laser in rat molars. Cavity preparation was made with Er:YAG laser in the mesial surface of the maxillary left first molar of 8-week-old Wistar rats. Contralateral first molar served as unirradiated control. Immediately, 6 and 12 h and 1, 2, 3, 5 and 7 days after the lasing (n = 5, each), specimens were collected and processed for immunohistochemistry for heat-shock protein (HSP)-25 and nestin as markers for odontoblast-lineage cells. Cell proliferation assay using bromodeoxyuridine (BrdU) labeling was also performed. Unirradiated teeth showed HSP-25- and nestin-immunoreactivity in odontoblasts. At 6-12 h after irradiation, the odontoblastic layer was disorganized and some of odontoblasts lost the immunoreactivity to HSP-25 and nestin. At 1-2 days, however, HSP-25- and nestin-immunoreactivities in the odontoblast layer showed a noticeable recovery, resulting in the rearrangement of odontoblast-like cells intensely immunoreactive to HSP-25 and nestin at 3-7 days. BrdU-positive cells showed a significant increase at 2 days (P < 0.05 vs. immediate previous time point; one-way analysis of variance and Scheffé post hoc test), peaked at 3 days and then decreased significantly (P < 0.05). It was concluded that under the present experimental condition in rat molars, cavity preparation with Er:YAG laser induced mild and reversible damage to odontoblasts. The reparative process was characterized by the rearrangement of HSP-25- and nestin-immunoreactive odontoblast-like cells, which took place subsequent to the odontoblastic layer disorganization with partial loss of these immunoreactivities. PMID:22736273

Shigetani, Yoshimi; Suzuki, Hironobu; Ohshima, Hayato; Yoshiba, Kunihiko; Yoshiba, Nagako; Okiji, Takashi

2012-06-27

265

Impaction of First Permanent Molars-Case Report.  

National Technical Information Service (NTIS)

Occasionally, the extraction of an impacted tooth provides a clinical challenge for an oral surgeon. Any tooth may be impacted, but third molars and maxillary cuspids are most frequently encountered followed by premolars and supernumerary teeth. Various s...

P. S. Grover L. Lorton

1982-01-01

266

Endodontic management of middle mesial canal of the mandibular molar.  

PubMed

Thorough knowledge of root canal morphology and unusual anatomy of the tooth is critical for successful endodontic treatment. Although the most common configuration is two roots and three root canals, mandibular molars might have many different combinations. In the literature, it is less described about three mesial canals and two distal canals in mandibular second molars, indicating a rare anatomical configuration. A case of unusual root canal morphology is presented to demonstrate anatomical variations in mandibular molars. Endodontic therapy was performed in a mandibular second molar with five separate canals, three mesial and two distal. This report points out the importance of looking for additional canals and unusual canal morphology, because knowledge of their existence might occasionally enable clinicians to treat a case successfully that otherwise might have ended in failure. In conclusion, every attempt should be made to find and treat all root canals of a tooth. PMID:23349182

Sundaresh, K J; Srinivasan, Raghu; Mallikarjuna, Rachappa; Rajalbandi, Sandeep

2013-01-23

267

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

268

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. 1065.642 Section...642 SSV, CFV, and PDP molar flow rate calculations. This section describes...the equations for calculating molar flow rates from various flow meters....

2010-07-01

269

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. 1065.642 Section...642 SSV, CFV, and PDP molar flow rate calculations. This section describes...the equations for calculating molar flow rates from various flow meters....

2013-07-01

270

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. 1065.642 Section...642 SSV, CFV, and PDP molar flow rate calculations. This section describes...the equations for calculating molar flow rates from various flow meters....

2009-07-01

271

The effect of maxillary molar distalization on cervical posture  

Microsoft Academic Search

Summary  PURPOSE: The objectives of this study were to determine whether maxillary molar distalization with a Pendulum appliance affects\\u000a the cervical posture, and whether lateral cephalometry can measure these changes. METHODS: Twenty Dental Class II subjects,\\u000a aged 11.5–15.5, were selected for maxillary molar distalization with a Pendulum appliance. Before treatment, a lateral cephalogram\\u000a was recorded in natural head position. The lateral

P. Currie; S. Lobo-Lob; P. Stark; N. Mehta

2009-01-01

272

Nanomechanical Behavior of Human Molars Soaked in Slight Acid Solutions  

Microsoft Academic Search

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

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

2009-01-01

273

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

274

Partially Biodegradable Temperature and PH Sensitive Hydrogel.  

National Technical Information Service (NTIS)

Partially biodegradable hydrogel that changes its volume and shape in response to change in pH and/or temperature is prepared by UV irradiation of composition comprising dextran-maleic acid monoester and N-isopropylacrylamide.

C. C. Chu X. Z. Zhang

2003-01-01

275

Effects of ammonia\\/silica molar ratio on the synthesis and structure of bimodal mesopore silica xerogel  

Microsoft Academic Search

A surfactant-templated silica xerogel with high pore volume, high porosity and narrow bimodal mesopore size distribution (designated as BMS) was synthesized by a judiciously controlled two-phase sol–gel processing under basic conditions. The properties of BMS silica mesostructure and the effect of ammonia\\/silica molar ratio on the resultant silica structure and morphology were assessed using various analytical techniques such as XRD,

Xiaozhong Wang; Wenhuai Li; Guangshan Zhu; Shilun Qiu; Dongyuan Zhao; Bing Zhong

2004-01-01

276

Molecular Volumes and the Stokes-Einstein Equation  

ERIC Educational Resources Information Center

|Examines the limitations of the Stokes-Einstein equation as it applies to small solute molecules. Discusses molecular volume determinations by atomic increments, molecular models, molar volumes of solids and liquids, and molal volumes. Presents an empirical correction factor for the equation which applies to molecular radii as small as 2 angstrom…

Edward, John T.

1970-01-01

277

Genetic integration of molar cusp size variation in baboons  

PubMed Central

Many studies of primate diversity and evolution rely on dental morphology for insight into diet, behavior, and phylogenetic relationships. Consequently, variation in molar cusp size has increasingly become a phenotype of interest. In 2007 we published a quantitative genetic analysis of mandibular molar cusp size variation in baboons. Those results provided more questions than answers, as the pattern of genetic integration did not fit predictions from odontogenesis. To follow up, we expanded our study to include data from the maxillary molar cusps. Here we report on these later analyses, as well as inter-arch comparisons with the mandibular data. We analyzed variation in two-dimensional maxillary molar cusp size using data collected from a captive pedigreed breeding colony of baboons, Papio hamadryas, housed at the Southwest National Primate Research Center. These analyses show that variation in maxillary molar cusp size is heritable and sexually dimorphic. We also estimated additive genetic correlations between cusps on the same crown, homologous cusps along the tooth row, and maxillary and mandibular cusps. The pattern for maxillary molars yields genetic correlations of one between the paracone-metacone and protocone-hypocone. Bivariate analyses of cuspal homologues on adjacent teeth yield correlations that are high or not significantly different from one. Between dental arcades, the non-occluding cusps consistently yield high genetic correlations, especially the metaconid-paracone and metaconid-metacone. This pattern of genetic correlation does not immediately accord with the pattern of development and/or calcification, however these results do follow predictions that can be made from the evolutionary history of the tribosphenic molar.

Koh, Christina; Bates, Elizabeth; Broughton, Elizabeth; Do, Nicholas T.; Fletcher, Zachary; Mahaney, Michael C.; Hlusko, Leslea J.

2010-01-01

278

Thiomers: influence of molar mass on in situ gelling properties.  

PubMed

The aim of this study was to investigate the influence of molar mass of thiolated polymers (thiomers) on their in situ gelling properties. Chitosan-thioglycolic acid (chitosan-TGA) and pectin-cysteine (pectin-Cys) of increasing molar mass were chosen to produce in situ gels in combination with carbamide peroxide. Low molar mass chitosan (~2 kDa) was prepared by oxidative degradation with NaNO(2), whereas pectin was depolymerized by heat treatment. Thiomers, displaying 1271-1616 ?mol (chitosan-TGA) and 305-403 ?mol (pectin-Cys) free thiol groups per gram polymer, were synthesized via amide bond formation mediated by a carbodiimide. The results showed that a reduction of molar mass combined with increased concentrations of both cationic chitosan-TGA and anionic pectin-Cys leads to higher final viscosities and to a higher relative increase in viscosity within 60 min and 180 min, respectively. Using this method, the dynamic viscosity of a very low molar mass chitosan-TGA (~2 kDa) could be increased 100,000-fold within 60 min and 390,000-fold within 180 min. In view of these in situ gelling properties carbohydrate thiomers might be useful for various pharmaceutical applications such as vehicle for drug delivery or as wound dressing material. PMID:22683454

Hintzen, Fabian; Laffleur, Flavia; Sarti, Federica; Shahnaz, Gul; Bernkop-Schnürch, Andreas

2012-06-07

279

Dental Treatment Needs of Permanent First Molars in Mashhad Schoolchildren  

PubMed Central

Background and aims In spite of their enormous importance, permanent first molars might be affected by caries in children in developing countries. The aim of this study was to evaluate the treatment needs of first permanent molars in a group of schoolchildren in Mashhad. Materials and methods This cross-sectional descriptive study was carried out on 700, 7-9 year-old students in primary schools in Mashhad. The schools were randomly selected from each district. Treatment needs and DMFT of first perma-nent molars were calculated. Data was analyzed using ANOVA, Chi-Square and t-test. Results A total of 95.3% of the children required dental treatment. Fissure sealant application and filling were the treat-ments most required in all age groups. The mean DMFT of first permanent molars was 1.31±1.4. It was significantly higher in girls than boys (P=0.040). Conclusion Great treatment needs and caries prevalence in permanent first molars in Mashhad schoolchildren show that dental caries is still a serious problem in the children of our society; therefore, education of parents and teachers is necessary for promoting children's oral health.

Ebrahimi, Masoumeh; Ajami, Behjat-Al-Molook; Sarraf Shirazi, Ali Reza; Afzal Aghaee, Monavar; Rashidi, Somayeh

2010-01-01

280

Requirement of alveolar bone formation for eruption of rat molars  

PubMed Central

Tooth eruption is a localized event that requires a dental follicle (DF) to regulate the resorption of alveolar bone to form an eruption pathway. During the intra-osseous phase of eruption, the tooth moves through this pathway. The mechanism or motive force that propels the tooth through this pathway is controversial but many studies have shown that alveolar bone growth at the base of the crypt occurs during eruption. To determine if this bone growth (osteogenesis) was causal, experiments were designed in which the expression of an osteogenic gene in the DF, bone morphogenetic protein-6 (BMP6), was inhibited by injection of the 1st mandibular molar of the rat with an siRNA targeted against BMP6. The injection was followed by electroporation to promote uptake of the siRNA. In 45 first molars injected, eruption either was delayed or completely inhibited (7 molars). In the impacted molars, an eruption pathway formed but bone growth at the base of the crypt was greatly reduced as compared to the erupted first molar controls. These studies show that alveolar bone growth at the base of the crypt is required for tooth eruption and that BMP6 may be an essential gene for promoting this growth.

Wise, Gary E.; He, Hongzhi; Gutierrez, Dina L.; Ring, Sherry; Yao, Shaomian

2011-01-01

281

Sonographic 'molar tooth' sign in the diagnosis of Joubert syndrome.  

PubMed

The characteristic imaging finding common to Joubert syndrome and related disorders is the 'molar tooth' sign. The prenatal diagnosis of Joubert syndrome using both ultrasound and fetal magnetic resonance imaging (MRI) in families with an affected child has been reported previously. We report two cases in which the molar tooth sign was identified by sonography at 26 + 4 weeks and at 20 + 6 weeks, respectively, prior to fetal MRI or genetic testing. In both cases the finding was subsequently confirmed on fetal MRI. As definitive prenatal genetic testing may not be conclusive in Joubert syndrome, the ability to identify the molar tooth sign sonographically before 24 weeks provides a valuable adjunct to prenatal diagnosis. PMID:21370303

Pugash, D; Oh, T; Godwin, K; Robinson, A J; Byrne, A; Van Allen, M I; Osiovich, H

2011-11-01

282

Use of sevoflurane inhalation sedation for outpatient third molar surgery.  

PubMed Central

This study attempted to determine if sevoflurane in oxygen inhaled via a nasal hood as a sole sedative agent would provide an appropriate level of deep sedation for outpatient third molar surgery. Twenty-four patients scheduled for third molar removal were randomly assigned to receive either nasal hood inhalation sevoflurane or an intravenous deep sedation using midazolam and fentanyl followed by a propofol infusion. In addition to measuring patient, surgeon, and dentist anesthesiologist subjective satisfaction with the technique, physiological parameters, amnesia, and psychomotor recovery were also assessed. No statistically significant difference was found between the sevoflurane and midazolam-fentanyl-propofol sedative groups in physiological parameters, degree of amnesia, reported quality of sedation, or patient willingness to again undergo a similar deep sedation. A trend toward earlier recovery in the sevoflurane group was identified. Sevoflurane can be successfully employed as a deep sedative rather than a general anesthetic for extraction of third molars in healthy subjects.

Ganzberg, S.; Weaver, J.; Beck, F. M.; McCaffrey, G.

1999-01-01

283

Aberration in the palatal root of the maxillary first molar.  

PubMed

Thorough knowledge of root canal morphology is essential for the endodontic therapy. Variations in the root and root canal morphology, especially in multirooted teeth, are a constant challenge for diagnosis and management. The dentist needs to be familiar with the various root canal configurations and their variations for successful endodontic therapy. There are rare variations in canal number and configuration in maxillary molars, which could affect treatment outcome. Two lingual root structures are occasionally found on human permanent maxillary molars. One of these is the normal lingual root, which is always present, the other is a supernumerary structure which can be located either mesiolingually (radix mesiolingualis) or distolingually (radix distolingualis). The purpose of this paper is to review the literature and to demonstrate a case report which describes the successful non-surgical endodontic management of an unusual maxillary first molar with four separate roots and four canals. PMID:23632609

Rajalbandi, Sandeep; Shingte, Sandhya Narayan; Sundaresh, K J; Mallikarjuna, Rachappa

2013-04-30

284

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.

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

2012-01-01

285

3D reconstruction of two C-shape mandibular molars.  

PubMed

Two mandibular second molars, with an indication of C-shape morphology were processed for 3-D reconstruction. After serial cross sectioning, photographs of the sections were digitized and by using surface representation, 3D reconstruction was achieved. The first molar as the 3D reconstruction showed was single rooted with one C-shaped root canal with two foramens, while the second one was double rooted with two root canals, one C-shaped and one thin, having a common foramen. PMID:9220739

Lyroudia, K; Samakovitis, G; Pitas, I; Lambrianidis, T; Molyvdas, I; Mikrogeorgis, G

1997-02-01

286

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

287

DFT-based quantum theory QSPR studies of molar heat capacity and molar polarization of vinyl polymers  

Microsoft Academic Search

In this study, the DFT\\/B3LYP level of theory with the 6-31G (d) basis set was used to calculate a set of quantum chemical\\u000a descriptors for structure units of vinyl polymers. These descriptors were used to predict the molar heat capacity of “liquid”\\u000a at constant pressure (C\\u000a \\u000a P\\u000a 1(298 K)) and the molar Lorentz and Lorenz polarization (P\\u000a LL). Two more

Xinliang Yu; Bing Yi; Wenhao Yu; Xueye Wang

2008-01-01

288

A Novel Mutation in Human PAX9 Causes Molar Oligodontia  

Microsoft Academic Search

Experimental and animal studies, as well as genetic mutations in man, have indicated that the development of dentition is under the control of several genes. So far, mutations in MSX1 and PAX9 have been associated with dominantly inherited forms of human tooth agenesis that mainly involve posterior teeth. We identified a large kindred with several individuals affected with molar oligodontia

S. A. Frazier-Bowers; D. C. Guo; A. Cavender; L. Xue; B. Evans; T. King; D. Milewicz; R. N. DSouza

2002-01-01

289

Thickness Measurement of Worn Molar Cusps by Ultrasound  

Microsoft Academic Search

This study aimed to evaluate the effectiveness of an ultrasonic system for in vitro measurement of cusp tips of human teeth. Each worn cusp of 12 molar teeth was measured with an industrial ultrasonic system. The teeth were sectioned and measured by polarized light microscopy. The ultrasonic measurements and histological readings were moderately correlated (r = 0.601, p < 0.01).

D. Arslantunali Tagtekin; F. Öztürk; M. Lagerweij; O. Hayran; G. K. Stookey; F. Çaliskan Yanikoglu

2005-01-01

290

Maxillary right second molar with two palatal root canals  

PubMed Central

We report a clinical case of maxillary right second molar with two palatal root canals. The morphology is atypical because it is characterized by two palatal roots with two canals with widely separated orifices and canals. Modifications to the normal access opening and examination of the pulpal floor for additional canals are stressed.

Prashanth, M B; Jain, Pradeep; Patni, Pallav

2010-01-01

291

Experience versus complication rate in third molar surgery  

Microsoft Academic Search

OBJECTIVES: The records of 1087 patients who underwent surgical removal of third molar teeth were prospectively examined to analyse the possible relationship between postoperative complications and the surgeon's experience parameter. METHOD AND MATERIALS: Seven surgeons (three specialists in surgical dentistry [specialists SD] and four oral and maxillofacial Senior House Officers [OMFS residents]) carried out the surgical procedures. For each patient,

Waseem Jerjes; Mohammed El-Maaytah; Brian Swinson; Bilquis Banu; Tahwinder Upile; Sapna D'Sa; Mohammed Al-Khawalde; Boussad Chaib; Colin Hopper

2006-01-01

292

Hemisection as an alternative treatment for vertically fractured mandibular molars.  

PubMed

Hemisection of mandibular molars may be a viable treatment option when vertical root fracture has occurred and the other root is healthy. This article discusses a case that presents the techniques involved in hemisection and restoration of the remaining tooth root. PMID:16494100

Kurtzman, Gregori M; Silverstein, Lee H; Shatz, Peter C

2006-02-01

293

Excess Molar Polarization in Binary Mixtures of Polar Liquids  

Microsoft Academic Search

Excess Molar Polarizations (?PW.Q., ?PD.D.) have been evaluated in the binary mixture of associated + associated and associated + nonassociated polar liquids using Winkelmann-Quitzsch and Davis-Douheret equations. It is observed that Winkelmann-Quitzsch equation ?PW.Q. is the more appropriate one for interpretation of dynamic characteristics of the molecular association in a liquid mixture.

S. K. Ray; J. Rath; C. Dwivedi

2001-01-01

294

Patent Accessory Canals: Incidence in Molar Furcation Region.  

National Technical Information Service (NTIS)

A total of 46 extracted maxillary and mandibular molars were examined to determine the incidence of accessory canals in the coronal and middle third of the root surface. A radiopaque dye was drawn through the root canal system under a vacuum of 5 p.s.i., ...

J. V. Lowman R. S. Burke G. B. Pelleu

1974-01-01

295

Unified analysis of noncomparative methods for measuring the molar absorptivity of triplet-triplet transitions  

SciTech Connect

Noncomparative techniques for the measurement of the molar absorptivity of triplet-triplet absorption transitions, epsilon/sub T/*, are reviewed. The methods covered include singlet depletion, total depletion, intensity variation (and its pulsed analog), partial saturation, and the so-called kinetic method. A critical analysis of the conceptual foundations of these varied approaches is performed. The fundamental equations of each technique are derived from a general three-state kinetic model of excitation and decay. From this unified approach it becomes very clear where assumptions are made in the traditional derivations of the methods. Additionally, one comparative method, that termed relative actinometry, is discussed, since it may be treated in a unimolecular fashion consistent with the above approach. The only major epsilon/sub T/* method excluded from this review is that involving intermolecular energy transfer, a technique which has been thoroughly documented elsewhere.

Carmichael, I.; Hug, G.L.

1987-08-01

296

Impaction of permanent mandibular second molar: A retrospective study  

PubMed Central

Objective: To determine the prevalence of impacted mandibular second molar (MM2) and the association between MM2 impaction and crowding. The clinical significance of the angle between first and second mandibular molar and of the space between the first mandibular molar (MM1) and the anterior margin of mandibular ramus in MM2 impaction were also evaluated. Material and Methods: In this retrospective study , from the dental records of 2,945 caucasian young orthodontics patients, 40 subjects with MM2 impaction were included in a study group (SG) and compared with a control group (CG) of 200 subjects without MM2 impactions. The crowding, the angle of inclination of MM2, the distance between MM1 and mandibular ramus, the canine and molar relationships, and the lower centre line discrepancy were measured. For the statistical analysis , descriptive statistics and t-Student for independent sample groups were used. Results: The prevalence of impacted MM2 was 1.36%. The independent-Samples t-Test between SG and CG showed: the presence of crowding (P?0.001), an higher angle values of MM2 inclination (P?0.001) and a smaller distance between MM1 and the anterior margin of mandibular ramus (P?0.001) in the SG. Conclusion: The impaction of MM2 is a relatively rare occurrence in orthodontic caucasian populations. The crowding, a higher angle values of MM2 inclination and a reduced distance between MM1 and the anterior margin of mandibular ramus, at the time of one third of MM2 root formation (T1), characterize MM2 impaction. Key words:Impacted mandibular second molar, impaction, orthodontics.

Altieri, Federica; Di Mambro, Alfonso; Galluccio, Gabriella; Barbato, Ersilia

2013-01-01

297

Activities and volumes in MgAl/sub 2/O/sub 4/ - Fe/sub 3/O/sub 4/ -. gamma. Fe/sub 8/3/O/sub 4/ spinels: implications for mantle oxygen fugacity  

SciTech Connect

The partial molar volumes of Fe/sub 3/O/sub 4/ and ..gamma..Fe/sub 8/3/O/sub 4/ components in synthetic spinels have been determined by x-ray powder diffraction with wet chemical analysis of Fe/sup 2 +//Fe/sup 3 +/. These data, in addition to published results for the join Fe/sub 3/O/sub 4/-..gamma..Fe/sub 8/3/O/sub 4/, characterize the partial molar volumes within the ternary spinel system. Both the Fe/sub 3/O/sub 4/-..gamma..Fe/sub 8/3/O/sub 4/ and MgAl/sub 2/O/sub 4/-..gamma..Fe/sub 8/3O/sub 4/ joins show nearly linear molar volumes of mixing. The MgAl/sub 2/O/sub 4/-Fe/sub 3/O/sub 4/ join, however, shows a significant positive deviation from ideality, with volumes given by: V(cm/sup 3//mole) = 44.58 X/sub mt/ + 43.65 X/sub ..gamma..hm/ + 39.79 X/sub sp/ + 0.26 X/sub mt/X/sub sp/ (1) The effect of pressure on published intrinsic oxygen fugacity measurements of spinel separates from upper mantle xenoliths may now be assessed. Applying the authors partial molar volume data to reaction (2) yields a ..delta..V of 0.408 cal/bar. This would correspond to an absolute increase in oxygen fugacity of 203 log units at 30kb and 1000/sup 0/C, or a relative increase of 1-2 log units in fO/sub 2/ when compared to a pressure corrected IW buffer. The oxygen fugacities of spinel-lherzolite xenoliths may also be estimated from Fe/sub 3/O/sub 4/ activities in spinel, which have been determined using a zirconia solid electrolyte. Applying the authors experimental activity data to coexisting olivine (X/sub fa/=0.10), orthopyroxene (X/sub fs/=0.10), spinel (X/sub mt/=0.01) assemblages and correcting to 30kb and 1000/sup 0/C yields a value for log fO/sub 2/ of -9.2 or 0.5 log units below the QFM buffer. These new data bring the previously disparate methods of estimating upper mantle oxygen fugacity into 1-2 log units better agreement of 30kb.

Mattioli, G.S.; Wood, B.J.

1985-01-01

298

Representations of partial derivatives in thermodynamics  

NSDL National Science Digital Library

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.

2012-05-15

299

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

300

Characterization of cellulose acetates according to DS and molar mass using two-dimensional chromatography.  

PubMed

A two-dimensional liquid chromatographic method (2D LC) was developed to analyze the heterogeneities of cellulose acetates (CA) in the DS-range DS=1.5-2.9 with respect to both, molar mass and degree of substitution (DS). The method uses gradient liquid chromatography (HPLC) as the first dimension in order to separate by DS followed by separation of the different fractions by size (SEC) in the second dimension. The 2D experiments revealed different correlations between gradient and SEC elution volume. These correlations might arise from differences in the synthetic conditions. The newly developed 2D LC separation therefore provides new insights into the heterogeneity of CAs. PMID:24053824

Ghareeb, Hewa Othman; Radke, Wolfgang

2013-08-06

301

Multiple melting peak analysis with gel-spun ultra-high molar mass polyethylene  

SciTech Connect

The multiple melting peaks observed on differential scanning calorimetry (DSC) of ultrahigh molar-mass PE fibers are analyzed as a function of sample mass. Using modern DSC capable of recognizing single fibers of microgram size, it is shown that the multiple peaks are in part or completely due to sample packing. Loosely packed fibers fill the entire volume of the pan with rather large thermal resistance to heat flow. On melting, the fibers contract and flow to collect ultimately at the bottom of the pan. This process seems to be able to cause an artifact of multistage melting dependent on the properties of the fibers. A method is proposed to greatly reduce, or even eliminate, errors of this type. The crucial elements of the analysis of melting behavior and melting temperature are decreasing the sample size and packing the individual fibers in a proper geometry, or to introduce inert media to enhance heat transport.

Boller, A.; Wunderlich, B. [Tennessee Univ., Knoxville, TN (United States). Dept. of Chemistry]|[Oak Ridge National Lab., TN (United States)

1996-12-31

302

A Physiological Permeability Study of Third Molar Dentine with Odontoblasts Preserved and Odontoblasts Free Preparations  

PubMed Central

Introduction Dentine a viable biological tissue forms an intimately related complex with the odontoblasts. Much has been question of the barrier properties of dentine within teeth and between teeth.. In human adults the odontoblasts are fully differentiated post-mitotic cells, which send its cytoplasmic processes into the dentinal tubules, yet various studies in the physic of fluid flow in dentine takes little recognition of its presence. The permeability of dentine has been implicated in a possible hydrodynamic mechanism by which rapid fluid movement in the tubules is thought to depolarise the nerve endings. Objective The innovative aim from this pilot investigation is to contribute to the understanding of the influence of odontoblasts on the permeability of human dentine. Methodology This study describes the permeability in odontoblast preserved and odontoblast free preparations in vitro i.e. comparing fluid flow across dentine in human third molars. The pulp tissues were removed from human third molars leaving the odontoblasts attached to the walls of the chamber. The specimens were then either fixed chemically (odontoblast-preserved specimens) or immersed in NaOH (odontoblast free specimens). Occlusal dentine was exposed by removing the enamel. The exposed dentine was placed in contact with water and the ingress of water into the pulp chamber was observed with a binocular microscope. A microlitre syringe was used to measure the volume of water accumulated at time intervals of several hours for up to 70 hours or more. Results The results showed that spontaneous flow continued in both preparations until equilibrium was reached. The relative final volumes were greater in the odontoblast free preparations than in the odontoblast preserved. Conclusion Water movement through odontoblast free dentine was believed to be driven by capillarity and through odontoblast preserved dentine by capillarity and osmotic pressure.

Ghazali, Farid Che

2000-01-01

303

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

304

Better outcomes in pulpotomies on primary molars with MTA  

Microsoft Academic Search

Data sourcesMedline, Cochrane Library, Embase, Science Citation Index and the China National Knowledge Infrastructure were used to source articles. In addition, identified papers' reference lists and their authors' other published literature were also scanned.Study selectionStudies of interest were randomised controlled trials of primary molar teeth where there was exposure of vital pulp caused by caries or trauma, with at least

Nicola Innes

2007-01-01

305

Rats’ responses to molar and local schedule constraints  

Microsoft Academic Search

Three experiments explored responses to molar and local schedule constraints. Thirsty rats pressed a lever for access to a\\u000a water spout. In Experiment 1, response totals were unaffected by two local schedule characteristics—the variability of the\\u000a instrumental requirement and the variability of the magnitude of contingent reward. Experiment 2 manipulated the correlation\\u000a between the instrumental requirement and the magnitude of

James Allison; Alison Buxton; Kevin E. Moore

1987-01-01

306

Foreign bodies in primary molars: a report of 2 cases.  

PubMed

Foreign bodies can be found in the pulps of primary teeth during routine oral examinations. These foreign bodies can result in painful complications. A detailed case history and clinical and radiographic examinations are necessary to come to a conclusion about the nature, size, and location of the foreign body, and to determine the difficulty involved in its removal. The purpose of this paper was to discuss 2 clinical cases and the management of foreign bodies found lodged in primary molars. PMID:22449509

Gujjar, Kumar Raghav; Algali, Ghazala; Omar, Suleiman M; Amith, H V; Anegundi, Rajesh T

307

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.

Shetty, Shibani; Rekha, K.

2009-01-01

308

Dentigerous Cyst Associated with a Formocresol Pulpotomized Deciduous Molar  

Microsoft Academic Search

This report presents a case of dentigerous cyst associated with a formocresol pulpotomized deciduous molar detected during routine examination. Dentigerous cyst is an epithelial-lined developmental cavity that encloses the crown of an unerupted tooth at the cementoenamel junction. The present case describes a 9-year-old girl sent to the dental clinic by her dentist, who had accidentally discovered in the panoramic

Manuela Pereira-Maestre; Dolores Conde-Fernández; Ignacio Vilchez; Juan José Segura-Egea; José Luis Gutiérrez-Pérez

2007-01-01

309

Determination of molar mass polydispersity index from dynamic rheological measurements  

Microsoft Academic Search

The polydispersity of the molar mass of a material influences the behaviour of its dynamic rheological propertiesG' (?) andG? (?). This is exemplified by the deviation from unity of the indexI = [2 - (d logG'\\/d log?)]\\/[1 - (d logG?\\/d log?)] in the terminal zone, i.e. at low frequencies. For a normal logarithmic distribution of species, a quantitative correlation may

G. Couarraze; J. L. Grossiord; F. Puisieux

1986-01-01

310

Third molars may have a negative impact on periodontal health  

Microsoft Academic Search

DesignThis was a cross-sectional study.Materials and methodsData were within a cohort study obtained between 1996 and 1999 on 6793 people of 52–74 years of age from the dental substudy of the Atherosclerosis Risk in Communities Study. The main independent variable was presence or absence of third molars, assessed visually, and the dependent variable was assessment of periodontal disease designated by

Graham J Smart

2005-01-01

311

Morphogenesis and bone integration of the mouse mandibular third molar.  

PubMed

The mouse third molar (M3) develops postnatally and is thus a unique model for studying the integration of a non-mineralized tooth with mineralized bone. This study assessed the morphogenesis of the mouse M3, related to the alveolar bone, comparing M3 development with that of the first molar (M1), the most common model in odontogenesis. The mandibular M3 was evaluated from initiation to eruption by morphology and by assessing patterns of proliferation, apoptosis, osteoclast distribution, and gene expression. Three-dimensional reconstruction and explant cultures were also used. Initiation of M3 occurred perinatally, as an extension of the second molar (M2) which grew into a region of soft mesenchymal tissue above the M2, still far away from the alveolar bone. The bone-free M3 bud gradually became encapsulated by bone at the cap stage at postnatal day 3. Osteoclasts were first visible at postnatal day 4 when the M3 came into close contact with the bone. The number of osteoclasts increased from postnatal day 8 to postnatal day 12 to form a space for the growing tooth. The M3 had erupted by postnatal day 26. The M3, although smaller than the M1, passed through the same developmental stages over a similar time span but showed differences in initiation and in the timing of bone encapsulation. PMID:21726286

Chlastakova, Ivana; Lungova, Vlasta; Wells, Kirsty; Tucker, Abigail S; Radlanski, Ralf J; Misek, Ivan; Matalova, Eva

2011-08-01

312

Characteristics of 351 supernumerary molar teeth In Turkish population  

PubMed Central

Objective: The aim of the present study was to evaluate the demographic profile of supernumerary molar (SM) teeth in people in various regions of Turkey. Study Design: A retrospective analysis was carried out on an initial sample of 104,902 subjects drawn from the ortopantographics files from 10 clinics in 7 Turkish cities with documentation of demographic data, the presence of SM teeth, their location, eruption, morphology, and position within the arch. In one region associated patho­logies and treatments were also evaluated. Results: Three hundred fifty-one SMs were detected in 288 patients, constituting 0.33% of the study subjects, with a greater frequency in females (56.4%). SMs were found more frequently in the maxilla (87.7%) than in the mandible, and distomolars (62.9%) were more common than paramolars. The SMs encountered were mostly of conical shape (45.7%), impacted (81.1%), and in a vertical position (52.1). The 33% of SM teeth were related to impacted molar teeth. Conclusion: The most common complication involving these teeth was soft tissue irritation. Demographic data from such specific extensive studies are crucial for improved diagnosis of SM teeth. Early detection allows for measures against complications and more successful therapy. Key words:Supernumerary molars, distomolar, paramolar, prevalence.

Kara, Muhammed I.; Ay, Sinan; Bereket, Cihan; Sener, Ismail; Bulbul, Mehmet; Ezirganl?, Seref; Polat, Hidayet B.

2012-01-01

313

3-D diagnosis-assisted management of anomalous mandibular molar  

PubMed Central

This case report describes the successful non-surgical endodontic management of carious exposed three-rooted mandibular molar with four root canals detected on the pre-operative radiograph taken with 20 degrees mesial angulation and confirmed with a 64-slice helical computed tomography scan-assisted 3-D-reconstructed images. Access cavity shape was modified to locate the extra canal with respect to the distolingual root in the left mandibular first molar. Copious irrigation was accomplished with 5.25% sodium hypochlorite and 17% EDTA. Biomechanical preparation was done using protapers. Calcium hydroxide dressing was done for 1 week. The tooth was obturated using gutta percha and AH 26 root canal sealer, and it was permanently restored with composite. Clinical examination on follow-up visits revealed no sensitivity to percussion and palpation in the left mandibular first molar. Thorough knowledge of root canal variations and use of advanced diagnostic modalities lead to successful non-surgical management of the complex cases.

Mittal, Neelam; Narang, Isha

2012-01-01

314

From molecular to molar: a paradigm shift in behavior analysis.  

PubMed Central

A paradigm clash is occurring within behavior analysis. In the older paradigm, the molecular view, behavior consists of momentary or discrete responses that constitute instances of classes. Variation in response rate reflects variation in the strength or probability of the response class. The newer paradigm, the molar view, sees behavior as composed of activities that take up varying amounts of time. Whereas the molecular view takes response rate and choice to be "derived" measures and hence abstractions, the molar view takes response rate and choice to be concrete temporally extended behavioral allocations and regards momentary "responses" as abstractions. Research findings that point to variation in tempo, asymmetry in concurrent performance, and paradoxical resistance to change are readily interpretable when seen in the light of reinforcement and stimulus control of extended behavioral allocations or activities. Seen in the light of the ontological distinction between classes and individuals, extended behavioral allocations, like species in evolutionary taxonomy, constitute individuals, entities that change without changing their identity. Seeing allocations as individuals implies that less extended activities constitute parts of larger wholes rather than instances of classes. Both laboratory research and everyday behavior are explained plausibly in the light of concrete extended activities and their nesting. The molecular- view, because it requires discrete responses and contiguous events, relies on hypothetical stimuli and consequences to account for the same phenomena. One may prefer the molar view on grounds of elegance, integrative power, and plausibility.

Baum, William M

2002-01-01

315

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

2011-03-18

316

Long-term cost of direct Class II molar restorations.  

PubMed

The aim was to evaluate the theoretical long-term treatment costs of direct class II molar restorations (amalgam, composite, glass ionomer) using the Median Survival Times (MSTs) derived from longevity studies conducted in the Nordic countries as time for replacement. Theoretical long-term cost calculations were based on fee schedules from all Public Dental Services (PDS) in Sweden, for patients, Social Insurance Offices (SI), and total cost. Costs over 10 years were calculated and sensitivity calculations were conducted in order to demonstrate the effect of different MSTs on the long-term cost development. Glass ionomer molar class II restorations had the lowest and composite restorations had the highest initial total cost. The highest total cost over 10 years was seen for composite restorations. Amalgam restorations had the lowest long-term total cost, except when the costs were based on the shortest MSTs for each material. As there were considerable differences in the long-term costs for class II molar restorations with different materials, the importance of cost-analyses over time cannot be enough emphasised when decisions about resource allocation in the dental health insurance system are considered. PMID:12425224

Sjögren, Petteri; Halling, Arne

2002-01-01

317

Variable permanent mandibular first molar: Review of literature  

PubMed Central

Introduction: The success of root canal therapy depends on the locations of all the canals, thourough debridement and proper sealing. At times the clinicians are challenged with variations in morphology of root canal. This review article attempts to list out all the variations of permanent mandibular first molar published so for in the literature. Materials and Methods: An exhaustive search was undertaken using PUBMED database to identify published literature from 1900 to 2010 relating to the root canal morphology of permanent first molar by using key words. The selected artcles were obtained and reviewed. Results: Total ninty seven articles were selected out of which 50 were original article and forty seven were case reports. The incidence of third canal in mesial root was 0.95% to 15%. The incidence of three rooted mandibular first molar was 3% to 33%. Only ninety cases reported with c-shape canal configuration. Incidence of Taurodintism without congenital disorder was very rare. Conclusion: The root canal treatment requires proper knowlegde of variations in root canal morphology in order to recognise, disinfect and seal all portal of exit. This can be accomplished with proper diagnosis using newer modes, modification in access preparation, use of operating microscope, enhanced methods of disinfecting and sealing of all canals.

Ballullaya, Srinidhi V; Vemuri, Sayesh; Kumar, Pabbati Ravi

2013-01-01

318

A Neanderthal lower molar from Stajnia Cave, Poland.  

PubMed

The primary aim of this study was to conduct a taxonomic assessment of the second of three isolated human teeth found in the Stajnia Cave (north of the Carpathians, Poland) in 2008. The specimen was located near a human tooth (S5000), which was identified by Urbanowski et al. (2010) as a Neanderthal permanent upper molar. Both of these teeth were excavated from the D2 layer, which belongs to the D stratigraphic complex comprising the archaeological assemblage associated with the Micoquian tradition. An Ursus spelaeus bone and Mammuthus primigenius tooth that were also excavated from the D2 layer were dated to >49,000 years BP (by AMS (14)C) and 52.9 ka BP (by U-Th), respectively. The sediment overlying stratigraphic complex D was dated to 45.9 ka BP by the OSL method. The S4300 tooth is a lower first or second permanent molar belonging to an individual other than that who once possessed the S5000 tooth. The S4300 tooth exhibits a combination of traits typical of Neanderthal lower molars, including a mid-trigonid crest, large anterior fovea, taurodontism and subvertical grooves on the interproximal face, indicating that this tooth belonged to a Neanderthal individual. The S4300 tooth from Stajnia Cave is one of the oldest human remains found in Poland. PMID:23415376

D?browski, P; Nowaczewska, W; Stringer, C B; Compton, T; Kruszy?ski, R; Nadachowski, A; Stefaniak, K; Urbanowski, M

2013-02-12

319

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.

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

2012-01-01

320

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

321

Risk of osteoradionecrosis after extraction of impacted third molars in irradiated head and neck cancer patients  

Microsoft Academic Search

PurposeThis study was performed to compare the risk of osteoradionecrosis (ORN) in head and neck cancer patients in whom 1 or more impacted third molars were extracted before radiotherapy with patients whose impacted third molars were left intact.

Hee-Kyun Oh; Mark S Chambers; Adam S Garden; Pei-Fong Wong; Jack W Martin

2004-01-01

322

Mass-spectrometric methods for determining isotopic composition and molar mass traceable to the SI, exemplified by improved values for nitrogen  

Microsoft Academic Search

The isotopic composition of atomic nitrogen and its molar mass (numerically equal to its atomic weight) M(N) were re-measured using recently improved accurate gas isotope-ratio mass spectrometry. We found in one sample of pure nitrogen, M(N) = 14,006 721 4 g mol-1 with a combined uncertainty uc = 0,000 001 8 g mol-1 (an average of four partially independent values).

P. de Bièvre; S. Valkiers; H. S. Peiser; P. D. P. Taylor; P. Hansen

1996-01-01

323

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

Microsoft Academic Search

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

Kornelius Kupczik; Jean-Jacques Hublin

2010-01-01

324

Patient with oligodontia treated with a miniscrew for unilateral mesial movement of the maxillary molars and alignment of an impacted third molar.  

PubMed

This report describes the treatment of a 20-year-old woman with a dental midline deviation and 7 congenitally missing premolars. She had retained a maxillary right deciduous canine and 4 deciduous second molars, and she had an impacted maxillary right third molar. The maxillary right deciduous second molar was extracted, and the space was nearly closed by mesial movement of the maxillary right molars using an edgewise appliance and a miniscrew for absolute anchorage. The miniscrew was removed, and the extraction space of the maxillary right deciduous canine was closed, correcting the dental midline deviation. After the mesial movement of the maxillary right molars, the impacted right third molar was aligned. To prevent root resorption, the retained left deciduous second molars were not aligned by the edgewise appliance. The occlusal contact area and the maximum occlusal force increased over the 2 years of retention. The miniscrew was useful for absolute anchorage for unilateral mesial movement of the maxillary molars and for the creation of eruption space and alignment of the impacted third molar in a patient with oligodontia. PMID:23992816

Maeda, Aya; Sakoguchi, Yoko; Miyawaki, Shouichi

2013-09-01

325

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

326

Concentration dependence of surface properties and molar volume of multicomponent system indium-tin-lead-bismuth  

NASA Astrophysics Data System (ADS)

The results of an experimental research of surface properties of the four-component system indium-tin-lead-bismuth are presented. The researches under discussion were carried out in a combined device in which the surface tension (?) is measured by the method of maximum pressure in a drop, and density (?) is measured by advanced aerometry. Measurement errors are 0.7 % for surface tension measurement, and 0.2 % for density measurement. The study of the concentration dependence of ? in this system has revealed the influence of the third and fourth components upon the characteristics of surface tension isotherms of the binary system indium-tin. It was found out that with an increase in the content of the third and fourth components the depth of the minimum on the surface tension isotherms of the indium-tin system ? decreases. On the basis of the concentration dependence of the phenomenon of concentration bufferity is revealed. It is shown that despite the complex character, isotherms of ? on beam sections of a multicomponent system do not contain qualitatively new features in comparison with the isotherms of these properties in lateral binary systems.

R, Dadashev; R, Kutuev; D, Elimkhanov

2008-02-01

327

The threshold strength of laminar ceramics utilizing molar volume changes and porosity  

Microsoft Academic Search

It has been shown that uniformly spaced thin compressive layers within a ceramic body can arrest the propagation of an otherwise catastrophic crack, producing a threshold strength: a strength below which the probability of failure is zero. Previous work has shown that the threshold strength increases with both the magnitude of the compressive stress and the fracture toughness of the

Michael Gene Pontin

2003-01-01

328

Dose–volume analysis of radiotherapy for T1N0 invasive breast cancer treated by local excision and partial breast irradiation by low-dose-rate interstitial implant  

Microsoft Academic Search

PurposeTo evaluate the toxicity of partial breast irradiation (RT) using escalating doses of low-dose-rate interstitial implant as the sole adjuvant local therapy for selected T1N0 breast cancer patients treated by wide local excision. The results of a European Organization for Research and Treatment of Cancer study have demonstrated a significant local control benefit using external beam RT to 65 Gy

Brian D Lawenda; Alphonse G Taghian; Lisa A Kachnic; Hanaa Hamdi; Barbara L Smith; Michele A Gadd; Thomas Mauceri; Simon N Powell

2003-01-01

329

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

330

Unilateral single-rooted primary mandibular first molar.  

PubMed

A 4-year-old boy reported food lodgement and pain in the lower left back tooth region. On examination, a deeply carious tooth with food lodgement was seen. On oral examination, numbers of teeth were found to be carious and required restorations and endodontic treatments according to radiographic evaluation. Radiograph of mandibular left first deciduous molar revealed an unusual morphology of root. It was single-rooted and presented with Vertucci's class I canal. The tooth was treated by pulpectomy followed by a stainless steel crown. All other carious teeth were treated as planned. PMID:23893279

Chaudhari, Purva; Mallikarjuna, Rachappa; Swadas, Milan; Dave, Bhavna

2013-07-26

331

Preheated shock experiments in the molten CaAl2Si2O8-CaFeSi2O6-CaMgSi2O6 ternary: A test for linear mixing of liquid volumes at high pressure and temperature  

NASA Astrophysics Data System (ADS)

We performed 17 new shock wave experiments on preheated (1673 K) hedenbergite liquid (CaFeSi2O6) and two model basalt liquids (an equimolar binary mix of CaAl2Si2O8 + CaFeSi2O6 and an equimolar ternary mix of CaAl2Si2O8 + CaFeSi2O6 +CaMgSi2O6) in order to determine their equations of state (EOS). Ambient pressure density measurements on these and other Fe-bearing silicate liquids indicate that FeO has a partial molar volume that is highly dependent on composition, which leads to large errors in estimates of the densities of Fe-bearing liquids at ambient pressure based on an ideal mixing of any fixed set of end-member liquids. We formulated a series of mixing tests using the EOS determined in this study to examine whether ideal mixing of volumes might nevertheless suffice to describe the ternary system CaAl2Si2O8-CaFeSi2O6-CaMgSi2O6 at high temperature and pressure. The ideal mixing null hypothesis is rejected; compositional variations in partial molar volume of FeO appear to extend to high pressure. Only densities of Fe-bearing liquid mixtures with oxide mole fraction of FeO less than 0.06 can be adequately approximated using an ideal solution.

Thomas, Claire W.; Asimow, Paul D.

2013-07-01

332

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

333

Unilateral failure of development of mandibular premolars and molars in an Eastern Grey kangaroo (Macropus giganteus) and its effects on molar progression.  

PubMed

An adult male Eastern Grey kangaroo from a wildlife reserve near Melbourne was submitted for necropsy examination and was discovered to have abnormal dentition. There was no evidence that any premolars or molars had ever been present on the right mandible, whilst the incisors were normal. The age of the kangaroo was estimated to be 1 year 9 months using the right maxillary molars and 2 years 4 months old using the contralateral side, presumably due to the asymmetry of the dental arcades. 'Lumpy jaw', a common periodontal disease of kangaroos, from which Bacteroides sp was cultured, was present on the base of the vertical ramus of the left mandible. Complete unilateral absence of premolar and molar teeth in the mandible of a kangaroo has not been described. This condition affected molar progression in both sets of maxillary molars. PMID:18271832

Barber, D; Campbell, J; Davey, J; Luke, T; Agren, E; Beveridge, I

334

Theoretical study of volume changes associated with the helix-coil transition of an alanine-rich peptide in aqueous solution.  

PubMed

The changes in the partial molar volume (PMV) associated with the conformational transition of an alanine-rich peptide AK16 from the alpha-helix structure to various random coil structures are calculated by the three-dimensional interaction site model (3D-RISM) theory coupled with the Kirkwood-Buff theory. The volume change is analyzed by decomposing it into contributions from geometry and hydration: the changes in the van der Waals, void, thermal, and interaction volume. The total change in the PMV is positive. This is primarily due to the growth of void space within the peptide, which is canceled in part by the volume reduction resulting from the increase in the electrostatic interaction between the peptide and water molecules. The changes in the void and thermal volume of the coil structures are widely distributed and tend to compensate each other. Additionally, the relations between the hydration volume components and the surface properties are investigated. We categorize coil structures into extended coils with the PMV smaller than helix and general coils with the PMV larger than helix. The pressure therefore can both stabilize and destabilize the coil structures. The latter seems to be a more proper model of random coil structures of the peptide. PMID:16001396

Imai, Takashi; Takekiyo, Takahiro; Kovalenko, Andriy; Hirata, Fumio; Kato, Minoru; Taniguchi, Yoshihiro

2005-10-01

335

Partially Recrystallised Nimonic Microstructures: A UK Interlaboratory Comparison.  

National Technical Information Service (NTIS)

A collaborative UK exercise was conducted to investigate the uncertainties associated with the measurement of important microstructural parameters in a partially recrystallized Nimonic 901 alloy. Measurements were made of recrystallized volume fraction, V...

B. Roebuck M. Stewart R. K. Varma L. P. Orkney

1995-01-01

336

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

337

An Evidenced Based Scoring System to Determine the Periodontal Prognosis on Molars.  

PubMed

Background: This retrospective study evaluated and assigned scores to six prognostic factors and derived a quantitative scoring system used to determine the periodontal prognosis on molar teeth. Methods: Data were gathered on 816 molars in 102 patients with moderate to severe periodontitis. The six factors evaluated, age, probing depth, mobility, furcation involvement, smoking, and molar type, were assigned a numerical score based on statistical analysis. The sum of the scores for all factors was used to determine the prognosis score for each molar. Only patients with all first and second molars at the initial examination qualified for the study. All patients were a minimum of 15 years post treatment. Results: The post treatment time ranged from 15 to 40 years and averaged 24 years. When the study was completed, 639 molars survived (78%), and of those surviving molars, 566 survived in health (89%). In molars with lower scores (1,2,and 3) the 15-year survival rates ranged from 99% to 96%. For scores 4, 5, 6 the 15 year survival rates ranged was 95% to 90% and for molars with scores of 7, 8, 9, and 10 the survival rates ranged from 86% to 67%. Conclusions: Our results indicate that the periodontal prognosis on molars diagnosed with moderate to severe periodontitis can be calculated using an evidence-based scoring system. PMID:23725028

Miller, Preston D; McEntire, Mark L; Marlow, Nicole M; Gellin, Robert G

2013-05-31

338

Dynamic Partial Evaluation  

Microsoft Academic Search

Dynamic partial evaluation performs partial evaluation as a side effect of evaluation, with no previous static analysis required.\\u000a A completely dynamic version of partial evaluation is not merely of theoretical interest, but has practical applications,\\u000a especially when applied to dynamic, reflective programming languages. Computational reflection, and in particular the use\\u000a of meta-object protocols (MOPs), provides a powerful abstraction mechanism, providing

Gregory T. Sullivan

2001-01-01

339

Molar extinction coefficients of some carbohydrates in aqueous solutions  

NASA Astrophysics Data System (ADS)

Molar extinction coefficients of some carbohydrates viz. L-arabinose (C5H10O5), D-glucose (C6H12O6), D-mannose (C6H12O6), D-galactose (C6H12O6), D(-) fructose (C6H12O6) and maltose (C12H24O12) in aqueous solutions have been determined at 81, 356, 511, 662, 1173 and 1332 keV by gamma ray transmission method in a narrow beam good geometry set-up. These coefficients have been found to depend upon the photon energy following a 4-parameter polynomial. These extinction coefficients for different sugars having the same molecular formula have same values varying within experimental uncertainty. Within concentration ranges studied, Beer--Lambert law is obeyed very well.

Singh, K.; Sandhu, G. K.; Lark, B. S.; Sud, S. P.

2002-03-01

340

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

341

Surface analysis of etched molar enamel by gas adsorption.  

PubMed

Much research has been devoted to the study of etched enamel, since it is critical to bonding. Currently, there are no precise data regarding the etched-enamel specific surface area. The aim of this study was to characterize, by two different methods, the surface of human dental enamel in vitro after being etched. It was hypothesized that differences would be observed between specimens in terms of specific surface area and grade of etching. Sixteen third molar enamel samples were etched for 30 sec with 37% phosphoric acid prior to being viewed by SEM. Etched enamel surfaces were graded according to the Galil and Wright classification. The total surface area of etched samples was determined by the BET gas absorption method. A substantial variability in total surface area was observed between and among samples. A Pearson's Correlation Coefficient showed a lack of relationship between etch pattern and total surface area. PMID:18502960

Orellana, M F; Nelson, A E; Carey, J P R; Heo, G; Boychuk, D G; Major, P W

2008-06-01

342

Molar extinction coefficients of some commonly used solvents  

NASA Astrophysics Data System (ADS)

Molar extinction coefficients of some commonly used solvents (ethanol (C2H5OH), methanol (CH3OH), propanol (C3H7OH), butanol (C4H9OH), water (H2O), toluene (C7H8), benzene (C6H6), carbontetrachloride (CCl4), acetonitrile (C4H3N), chlorobenzene (C6H5Cl), diethylether (C4H10O) and dioxane (C4H8O2)) have been determined by a well-collimated narrow beam transmission geometry at 279, 356, 662, 1173, 1252 and 1332 keV ? rays. The total ? ray interaction cross sections of these solvents have also been determined. A good agreement has been obtained between the experimental results with the theoretical values evaluated through XCOM calculations.

Kumar, Ashok; Singh, Sukhpal; Singh Mudahar, Gurmel; Singh Thind, Kulwant

2006-07-01

343

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

344

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

2010-12-31

345

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

346

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

347

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

PubMed Central

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.

Torabzadeh, Hassan; Asgary, Saeed

2013-01-01

348

Chiral and continuum extrapolation of partially quenched lattice results  

SciTech Connect

The vector meson mass is extracted from a large sample of partially quenched, two-flavor lattice QCD simulations. For the first time, discretization, finite-volume and partial quenching artifacts are treated in a unified chiral effective field theory analysis of the lattice simulation results.

C.R. Allton; W. Armour; D.B. Leinweber; A.W. Thomas; R.D. Young

2005-04-01

349

Hypohyperdontia: Agenesis of three third molars and mandibular centrals associated with midline supernumerary tooth in mandible  

PubMed Central

Agenesis of teeth in a patient who also presents with a supernumerary tooth is one of the rare numerical anomalies in human dentition. Agenesis of third molars was shown to be associated with other missing permanent teeth. A review of literature on hypodontia including third molar agenesis, hyperdontia and a concomitant presence of these two conditions which is termed as hypohyperdontia is presented along with a case showing agenesis of three third molars, both mandibular central incisors and a midline supernumerary tooth.

Nuvvula, Sivakumar; Kiranmayi, M.; Shilpa, G.; Nirmala, S. V. S. G.

2010-01-01

350

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

351

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

352

[Maxillary second molar with curved single root and single canal: a case report].  

PubMed

Incidence rate of single root canal in maxillary second molar is very low. The emergence of curved single root canal in maxillary second molar with single root is especially rare. A case of curved single root canal in maxillary second molar with single root was successfully treated and reported in this article. This report also highlighted the role of cone beam computed tomography as an objective method to confirm the three-dimensional anatomy of teeth. PMID:21427914

Wang, Yao; Hui, Xi; Huang, Ding-ming

2011-02-01

353

Quantification of chlorinated naphthalenes with GC-MS using the molar response of electron impact ionization  

Microsoft Academic Search

The concept of the molar response (MR) in HRGC\\/EI-MS has been checked for naphthalene and three chlorinated naphthalenes: 1-chloronaphthalene, 1,2,3,4-tetrachloronaphthalene and octachloronaphthalene. The molar response factors increase with increasing degree of chlorination. When the ion yield is normalized for the ionization cross section Q of the molecule, a constant value of injected molar mass to signal intensity is obtained for

Thomas Wiedmann; Karlheinz Ballschmiter

1993-01-01

354

Management of mandibular first molar with four canals in mesial root.  

PubMed

Successful root canal treatment depends on adequate cleaning, shaping, and filling of the root canal system. The presence of middle mesial (MM) root canal of mandibular molars has been reported by various authors. But incidence of four canals in mesial root of mandibular molar is very rare. The aim of this case report is to present and describe the identification and management of a mandibular first molar with four canals in the mesial root and single canal in the distal root. PMID:24082581

Subbiya, Arunajatesan; Kumar, Krishnamurthy Sathish; Vivekanandhan, Paramasivam; Prakash, Venkatachalam

2013-09-01

355

Three-rooted mandibular first primary molar: Report of three cases.  

PubMed

Accessory root formation in primary teeth is an uncommon finding. An awareness and understanding of the presence of additional roots and unusual root canal morphology is essential as it determines the successful outcome of the endodontic treatment.This paper presents three case reports on the presence of three-rooted mandibular first primary molar (primary three-rooted mandibular left first molar and bilateral mandibular first molar). PMID:22629056

Gupta, Shilpi; Nagaveni, N B; Chandranee, N J

2012-04-01

356

Three-rooted mandibular first primary molar: Report of three cases  

PubMed Central

Accessory root formation in primary teeth is an uncommon finding. An awareness and understanding of the presence of additional roots and unusual root canal morphology is essential as it determines the successful outcome of the endodontic treatment. This paper presents three case reports on the presence of three-rooted mandibular first primary molar (primary three-rooted mandibular left first molar and bilateral mandibular first molar).

Gupta, Shilpi; Nagaveni, N. B.; Chandranee, N. J.

2012-01-01

357

Independent and Confluent Middle Mesial Root Canals in Mandibular First Molars: A Report of Four Cases  

PubMed Central

Mandibular molars demonstrate considerable variations with respect to number of roots and root canals. The possibility of additional root canals should be considered even in teeth with a low frequency of abnormal root canal anatomy. This paper discusses the endodontic management of the rare anatomical complexity middle mesial canals in mandibular first molar and also serves to remind the clinicians that such anatomical variations should be taken into account during the endodontic treatment of the mandibular molars.

Deepalakshmi, Mohanavelu; Karumaran, Chellasamy Savarimala; Miglani, Revathi; Indira, Rajamani

2012-01-01

358

Management of mandibular first molar with four canals in mesial root  

PubMed Central

Successful root canal treatment depends on adequate cleaning, shaping, and filling of the root canal system. The presence of middle mesial (MM) root canal of mandibular molars has been reported by various authors. But incidence of four canals in mesial root of mandibular molar is very rare. The aim of this case report is to present and describe the identification and management of a mandibular first molar with four canals in the mesial root and single canal in the distal root.

Subbiya, Arunajatesan; Kumar, Krishnamurthy Sathish; Vivekanandhan, Paramasivam; Prakash, Venkatachalam

2013-01-01

359

Partial oxidation process  

SciTech Connect

A process is provided for the partial oxidation of a high metals or ash containing liquid hydrocarbonaceous fuel or a slurry of solid carbonaceous fuel to simultaneously produce saturated and unsaturated raw streams of synthesis gas, reducing gas, or fuel gas. Two continuous partial oxidation reactions in two separate reaction zones go on simultaneously. The fuel feed to the first partial oxidation zone is said fresh high metals or ash containing fuel. The raw product gas stream from the first partial oxidation zone is split into first and second split gas streams. The first split gas stream may be cooled in a radiant and/or convection type gas cooler without fouling heat exchange surfaces. The fuel feed to the second partial oxidation zone is a pumpable slurry which is prepared from the entrained matter that is separated from said gas streams during quench cooling and cleaning operations and which contains a comparatively high amount of metals and/or ash. The partial oxidation reaction takes place in the second partial oxidation zone in a reducing atmosphere that includes the second split raw product gas stream from the first partial oxidation zone. By the subject process, there is a reduction in the unconverted carbon produced without any significant loss in efficiency. Further, the life of the cooler for the raw product gas stream is increased.

Jahnke, F. C.

1985-10-15

360

Partial Cavity Drag Reduction  

Microsoft Academic Search

The notion of using air to reduce a ship's frictional drag dates back to the 19^th century. Bubbles, air layers and air filled cavities have been proposed, but there has been little systematic research published. To address this, partial cavity drag reduction experiments were carried out at the W. B. Morgan Large Cavitation Channel. The partial cavity was investigated at

Simo Makiharju; Keary Lay; Ryo Yakushiji; Marc Perlin; Steven Ceccio

2008-01-01

361

Personalization by Partial Evaluation  

Microsoft Academic Search

this paper is to model personalization by the programmatic notion ofpartial evaluation. Partial evaluation is a technique used to automatically specialize programs,given incomplete information about their input. The methodology presented here models a collectionof information resources as a program (which abstracts the underlying schema of organizationand flow of information), partially evaluates the program with respect to user input, and recreatesa

Naren Ramakrishnan; Mary Beth Rosson

362

Partial update LMS algorithms  

Microsoft Academic Search

Partial updating of LMS filter coefficients is an effective method for reducing computational load and power con- sumption in adaptive filter implementations. This paper presents an analysis of convergence of the class of Sequential Partial Update LMS algorithms (S-LMS) under various assumptions and shows that divergence can be prevented by scheduling coefficient updates at random, which we call the Stochastic

Mahesh Godavarti; Alfred O. Hero III

2005-01-01

363

Measurement of absolute myocardial blood flow with H/sub 2//sup 15/O and dynamic positron-emission tomography. Strategy for quantification in relation to the partial-volume effect  

SciTech Connect

An in vivo technique was developed for measuring the absolute myocardial blood flow with H/sub 2//sup 15/O and dynamic positron-emission tomography. This technique was based on a new model involving the concept of the tissue fraction, which was defined as the fraction of the tissue mass in the volume of the region of interest. The myocardium was imaged dynamically by positron-emission tomography, starting at the time of intravenous bolus injection of H/sub 2//sup 15/O. The arterial input function was measured continuously with a beta-ray detector. A separate image after C/sup 15/O inhalation was also obtained for correction of the H/sub 2//sup 15/O radioactivity in the blood. The absolute myocardial blood flow and the tissue fraction were calculated for 15 subjects with a kinetic technique under region-of-interest analysis. These results seem consistent with their coronary angiographic findings. The mean value of the measured absolute myocardial blood flows in normal subjects was 0.95 +/- 0.09 ml/min/g. This technique detected a diffuse decrease of myocardial blood flow in patients with triple-vessel disease.

Iida, H.; Kanno, I.; Takahashi, A.; Miura, S.; Murakami, M.; Takahashi, K.; Ono, Y.; Shishido, F.; Inugami, A.; Tomura, N.

1988-07-01

364

Partial Torus Instability  

NASA Astrophysics Data System (ADS)

Flux ropes are now generally accepted to be the magnetic configuration of Coronal Mass Ejections (CMEs), which may be formed prior or during solar eruptions. In this study, we model the flux rope as a current-carrying partial torus loop with its two footpoints anchored in the photosphere, and investigate its instability in the context of the torus instability (TI). Previous studies on TI have focused on the configuration of a circular torus and revealed the existence of a critical decay index. Our study reveals that the critical index is a function of the fractional number of the partial torus, defined by the ratio between the arc length of the partial torus above the photosphere and the circumference of a circular torus of equal radius. We refer to this finding the partial torus instability (PTI). It is found that a partial torus with a smaller fractional number has a smaller critical index, thus requiring a more gradually decreasing magnetic field to stabilize the flux rope. On the other hand, the partial torus with a larger fractional number has a larger critical index. In the limit of a circular torus when the fractional number approaches one, the critical index goes to a maximum value that depends on the distribution of the external magnetic field. We demonstrate that the partial torus instability helps us to understand the confinement, growth, and eventual eruption of a flux rope CME.

Olmedo, Oscar; Zhang, J.

2010-05-01

365

Flexion characteristics of four-unit fixed partial denture frameworks using holographic interferometry.  

PubMed

Flexion of a metal/ceramic fixed partial denture (FPD) framework under function can cause fracture of the porcelain or deterioration of the cement seal. This study evaluated the flexion under compressive load of a four-unit mandibular FPD replacing the second premolar and the first molar. Testing was accomplished with elapsed time holographic interferometry, using 39 porcelain fused-to-metal frameworks cast with a silver-palladium alloy. The results demonstrated that solder joints at the junction of the premolar and molar pontics flexed under a reduced compressive load and exhibited a higher failure rate than other connector designs. PMID:1356156

Goldstein, G R; Wesson, A; Schweitzer, K; Cutler, B

1992-05-01

366

Partially coherent lensfree tomographic microscopy?  

PubMed Central

Optical sectioning of biological specimens provides detailed volumetric information regarding their internal structure. To provide a complementary approach to existing three-dimensional (3D) microscopy modalities, we have recently demonstrated lensfree optical tomography that offers high-throughput imaging within a compact and simple platform. In this approach, in-line holograms of objects at different angles of partially coherent illumination are recorded using a digital sensor-array, which enables computing pixel super-resolved tomographic images of the specimen. This imaging modality, which forms the focus of this review, offers micrometer-scale 3D resolution over large imaging volumes of, for example, 10–15 mm3, and can be assembled in light weight and compact architectures. Therefore, lensfree optical tomography might be particularly useful for lab-on-a-chip applications as well as for microscopy needs in resource-limited settings.

Isikman, Serhan O.; Bishara, Waheb; Ozcan, Aydogan

2012-01-01

367

Prognosis of partial epilepsy.  

PubMed Central

The prognosis of partial epilepsy in childhood (excluding cases of benign partial epilepsy) was studied; the average follow up period was 7.4 years. Improvement rate of seizure status was 82.3%. We studied favourable prognostic factors and found that those most often associated with seizure improvement were familial convulsions and idiopathic forms, no generalised seizures before partial onset, low frequency of seizures after 12 months of treatment, short duration of epilepsy, and no background activity abnormalities on electroencephalography. We also observed such factors as mental retardation, neurological abnormalities, and behaviour and cognitive disorders. Factors that determined the prognosis for social adjustment were similar to those for seizure improvement. We discuss the favourable prognosis of partial seizures in childhood and the predictive factors.

Porro, G; Matricardi, M; Guidetti, V; Benedetti, P

1988-01-01

368

Pharmacodynamic responses of exogenous epinephrine during mandibular third molar surgery  

PubMed Central

Background: The systemic effects attributable to the injection of dental local anesthetic solutions have been the subject of discussion for many years. Aim and Objective: The aim of the present study was to investigate the biochemical and hemodynamic effects of adrenaline in lignocaine local anesthetic solutions when used in clinical doses in patients undergoing third molar surgery under general anesthesia. Materials and Methods: Of the total 30 patients, 15 were given local anesthetic solution containing adrenaline and the other 15 were given the same without adrenaline. Hemodynamic and biochemical parameters were recorded at considerable intervals. The changes from the pre-local anesthetic (baseline) values with each treatment were compared by analysis of variance and Student's t-test. The changes within each treatment were compared by the paired t-test. Results and Conclusion: This study shows that exogenous adrenaline administration in clinical doses produces systemic effects even in conditions where the endogenous release of the catecholamines would be expected to be considerable.

Sivanmalai, Sivaraj; Annamalai, Sivakumar; Kumar, Santhosh; Prince, Christo Naveen; Chandrakala; Thangaswamy, Vinod

2012-01-01

369

Management of middle mesial canal in mandibular second molar  

PubMed Central

The primary objective of endodontic therapy is to achieve a three-dimensional obturation of the root canal space after adequate preparation of the canal space to remove the tissue debris, microorganisms, and their byproducts. Anatomical variations have frequently been encountered in endodontic practice and have to be adequately managed by the clinician. Missed roots and canals are a major reason for failure of therapy. Technological advances have given the clinician ample opportunity to identify and treat these aberrations successfully. The present report describes a left mandibular second permanent molar requiring root canal treatment, found to have three separate canals in the mesial root. This case demonstrates a rare anatomical configuration and emphasizes the need for the clinician to be aware of and look out for such variations and use adequate diagnostic methodologies prior to and during therapy to detect such variations. The possibility of additional canals, whenever in doubt, should be explored with the assistance of technologies such as those of magnification and illumination and various diagnostic aids. Operator experience has also shown to be a key factor in negotiation and management of these aberrant canal configurations.

Karunakaran, J. V.; Shobana, R.; Kumar, Mohan; Kumar, Senthil; Mankar, Sunil

2012-01-01

370

Mass or molar? Recommendations for reporting concentrations of therapeutic drugs.  

PubMed

A working party (WP) from the Australasian Association of Clinical Biochemists, Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists, Royal College of Pathologists of Australasia and Royal Australasian College of Physicians recommends the following: *mass units should be used for reporting therapeutic drug concentrations in Australia and New Zealand; and the litre (L) should be used as the denominator when expressing concentration. Examples of these units are mg/L and ?g/L Exceptions to these principles include: *drugs for which there is current uniformity of reporting and supporting information using molar units, notably lithium (mmol/L) and methotrexate (?mol/L); *drugs that are also present as endogenous substances, where the units used routinely should continue to be used. This applies to many substances, including minerals (eg, iron; ?mol/L), vitamins (eg, vitamin D; nmol/L) and hormones (eg, thyroxine; pmol/L). *drugs for which the denominator is not a 198 of fluid and there is international uniformity of reporting (eg, thiopurine metabolites; per 109 red blood cells). These recommendations relate to drugs that are used therapeutically, whether measured for therapeutic drug monitoring purposes or for assessment of overdose. Other substances, such as drugs of misuse, heavy metals or environmental toxins, were not considered by the WP and are thus not covered by this document. These recommendations should also be applied to other supporting documentation such as published guidelines, journal articles and websites. The implementation of these recommendations in New Zealand is subject to local confirmation. PMID:23581955

Jones, Graham R D; Bryant, Stewart; Fullinfaw, Robert; Ilett, Ken; Miners, John O; Morris, Raymond G; Doogue, Matthew P

2013-04-15

371

Root canals in two-rooted maxillary second molars.  

PubMed

The aim of this study was to register the root canal number, root canal position, and root canal cross-section in human two-rooted, permanent maxillary second molars. One hundred and fifty-nine such teeth extracted in Denmark were cross-sectioned at the mid-root level and apically in accordance with precise guidelines. The observations were made in a stereomicroscope, corresponding to the above-mentioned section levels. At mid-root there were two canals present in 11% of the teeth examined; the canals were located mesially and distofacially, mesiofacially and distally, or facially and lingually. Three canals positioned mesiofacially, distofacially, and lingually were observed in 89% of the teeth. At the same level 62% of the canal cross-sections were noncircular, some being, for instance, C-shaped, whereas 38% of the cross-sections were circular. Apically, two canals were found, representing 19% of the teeth, with the canal position as at mid-root; 81% of the teeth were three-canaled with the same canal position as at mid-root. At the apical level 60% of the canal cross-sections were noncircular, whereas 40% of the cross-sections were circular. PMID:9477024

Carlsen, O; Alexandersen, V

1997-12-01

372

Incidence of oral sinus communications in 389 upper third molar extraction  

Microsoft Academic Search

Introduction. The incidence of oral sinus communications (OSC) following the extraction of an upper third molar re- mains uncertain. Objectives. The purpose of this study was to determine the incidence of OSC following the extraction of 389 consecu- tive upper third molars during 2003 in the Master of Oral Surgery and Orofacial Implantology (Barcelona University, Spain). Patients and method. Different

Marta del Rey Santamaría; Eduard Valmaseda Castellón; Leonardo Berini Aytés; Cosme Gay Escoda

373

Influence of overlay restorative materials and load cusps on the fatigue resistance of endodontically treated molars  

Microsoft Academic Search

Objectives: To assess the influence of restorative materials and load cusps on the fatigue resistance of endodontically treated molars. Method and Materials: Thirty extracted molars received root canal treatment followed by a standardized tooth preparation (3-mm cuspal reduction and immediate dentin sealing). Twenty Cerec 3 overlays (Sirona Dental Systems) were milled in the ceramic Vita MKII block (Vident; groups MKIIGL

Pascal Magne; Alena Knezevic

374

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

375

Enamel thickness and the helicoidal wear plane in modern human mandibular molars  

Microsoft Academic Search

Helicoid occlusion has long been recognized as a feature characterizing the human dentition and has been viewed as an important morphological marker in the transition from Australopithecus to Homo. The hallmark of helicoidal wear is a buccal wear slope in anterior mandibular molars (and a corresponding lingual slope of wear in anterior maxillary molars) reversing to a flat or lingual-oriented

Gary T. Schwartz

2000-01-01

376

Morphological and anthropological aspects of human triangular deciduous lower first molar teeth  

Microsoft Academic Search

The crown and root morphology, and bilateral occurrence of human deciduous lower first molars that exhibited a triangular occlusal outline, taken from excavated samples of Japanese, Jomonese and Iraqi origin, were investigated. The crowns of triangular teeth had smaller mesiodistal and larger buccolingual diameters than normally shaped deciduous lower first molars. An elongated buccolingual diameter was derived from the buccal

Yoshikazu Kitagawa; Yoshitaka Manabe; Joichi Oyamada; Atsushi Rokutanda

1996-01-01

377

Influence of a Barley Product on the Eruption and Caries of Rat Molars  

Microsoft Academic Search

SYNOPSIS IN INTERLINGUALE INFLUENTIA DE UN PRODUCTO DE HORDEO SUPER LE ERUPTION E LE CARIOGENESE DE MOLARES DE RATTOS.—Le substitution de hordeo pro 20 pro cento de un dieta componite secundo datos de human consumo medie causava un plus precoce eruption del tertie molares in rattos de secunde generation del linea Wistar durante que inhibition de carie dental esseva constatate

L. M. Dalderup; M. M. Stroo

1966-01-01

378

Effect of Primary Molar Extraction on Gingival Emergence of Succedaneous Tooth  

Microsoft Academic Search

SYNOPSIS IN INTERLINGUALE EFFECTO DEL EXTRACTION DE MOLARES PRIMARI SUPER LE EMERGENTIA GINGIVAL DEL DENTES SUCCEDANEE.—Le tempore del emergentia gingival de dentes bicuspidal subjacente a bilateralmente comparabile pares de primari dentes molar, un del quales esseva extrahite durante que le altere se exfoliava naturalmente, esseva comparate a base de serial modulos dental e de roentgenogrammas in 20 juveniles norteamerican de

W. F. OMeara

1966-01-01

379

Radiographic Survey of Third Molar Development in Relation to Chronological Age Among Japanese Juveniles  

Microsoft Academic Search

The aim of the present study was to establish Japanese reference material on the third molar development of Japanese juveniles for forensic application. Observations were performed on the orthopantomograms of 1282 Japanese patients between the ages of 14.0 and 24.0 years. Demirjian formation stages of the maxillary and mandibular third molars were recorded for chronological evaluation of wisdom teeth and

Akita Hondo

380

Developing a measure of patient perceptions of short-term outcomes of third molar surgery  

Microsoft Academic Search

Purpose: The purpose of the study was to develop an instrument to measure patients' perceptions of their experiences after the removal of third molar teeth.Methods: Nineteen patients (ages 18 to 25 years) who underwent surgical removal of four third molars after local treatment for mild symptoms of pericoronitis completed a newly developed 14-item instrument each evening for the 14-day period

Daniel A Shugars; Ken Benson; Raymond P White; Kit N Simpson; James D Bader

1996-01-01

381

The third molar controversy: Framing the controversy as a public health policy issue  

Microsoft Academic Search

Purpose: This article summarizes the current research available concerning the removal of impacted third molars, and provides a background from which practitioners, public health policy advocates, and third-party payers can more objectively assess the the issues of appropriateness of care and overutilization of third molar surgery.Materials and Methods: A literature review was undertaken, with emphasis on noninterventional outcome studies and

William G Flick

1999-01-01

382

Evaluation of factors predictive of lingual nerve injury in third molar surgery  

Microsoft Academic Search

The aim of this study was to investigate risk factors for temporary and permanent lingual nerve injury after extraction of mandibular third molars. It was based on a 4-year prospective study of 2134 consecutive mandibular third molar operations in 1384 consecutive day case patients. During the study period (1994–1998) data were collected prospectively on patient, dental and surgical factors and

T. Renton; M. McGurk

2001-01-01

383

Success rate of formocresol pulpotomy in primary molars restored with stainless steel crown vs amalgam  

Microsoft Academic Search

Purpose: The purpose of this retrospective study was to compare the success rates of formocresol pulpotomy in primary molars restored with stainless steel crowns (SSC) to those restored with amalgam (AM). Methods: Radiographs of pulpotomized primary molars restored with SSC or AM in the principal author's pediatric dentist practice were evaluated and defined as a \\

Gideon Holan; Anna B. Fuks

2002-01-01

384

Mineral trioxide aggregate vs. formocresol in pulpotomized primary molars: a preliminary report  

Microsoft Academic Search

Purpose: The aim of this study was to compare the effect of mineral trioxide aggregate (MTA) to that of formocresol (FC) as pulp dressing agents in pulpotomized primary molars with cari- ous pulp exposure. Methods: Forty-five primary molars of 26 children were treated by a conventional pulpotomy technique. The teeth were randomly assigned to the MTA (experimental) or FC (control)

Eliezer Eidelman; Anna B. Fuks

2001-01-01

385

Comparison of mineral trioxide aggregate and formocresol as pulp medicaments for pulpotomies in primary molars  

Microsoft Academic Search

Purpose The aim of this study was to compare the effect of white mineral trioxide aggregate (MTA) to that of formocresol (FC) as pulp dressing agents in pulpotomised primary molars.Methods In this clinical trial study, 60 lower second primary molars of 46 children were treated by a conventional pulpotomy technique. The teeth were randomly assigned to the MTA (experimental) and

H. Noorollahian

2008-01-01

386

40 CFR 1066.610 - Mass-based and molar-based exhaust emission calculations.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Mass-based and molar-based exhaust emission...PROCEDURES Calculations § 1066.610 Mass-based and molar-based exhaust emission calculations. (a) Calculate your total mass of emissions over a test cycle as...

2013-07-01

387

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

388

Postoperative Infection after Surgical Removal of Impacted Mandibular Third Molars: An Analysis of 110 Consecutive Procedures  

Microsoft Academic Search

Objective: The aim of this study was to evaluate the rate of postoperative infection and other complications after the surgical removal of impacted mandibular third molars. Subjects and Materials: Medical records of 110 consecutive patients with 130 consecutive surgical extractions of impacted lower third molar teeth performed under local anesthetic using strict aseptic techniques were reviewed and analyzed. No systemic

Adel Al-Asfour

2009-01-01

389

Clines with partial panmixia  

Microsoft Academic Search

In spatially distributed populations, global panmixia can be regarded as the limiting case of long-distance migration. The effect of incorporating partial panmixia into single-locus clines maintained by migration and selection is investigated. In a diallelic, two-deme model without dominance, partial panmixia can increase or decrease both the polymorphic area in the plane of the migration rates and the equilibrium gene-frequency

Thomas Nagylaki

390

Partial Rotator Cuff Ruptures  

Microsoft Academic Search

\\u000a Partial rotator cuff ruptures are not rare and occur mainly in the supraspinatus tendon and may extend to that of infraspinatus,\\u000a but rarely to the tendon of subscapularis. Isolated lesions in the tendons of infraspinatus, teres minor or subscapularis\\u000a are rare. Partial ruptures usually occur before the sixth decade of life and can be a cause of unexplained pain in

Antonio Cartucho

391

Partial Torus Instability  

NASA Astrophysics Data System (ADS)

Flux ropes are now generally accepted to be the magnetic configuration of coronal mass ejections (CMEs), which may be formed prior to or during solar eruptions. In this study, we model the flux rope as a current-carrying partial torus loop with its two footpoints anchored in the photosphere, and investigate its stability in the context of the torus instability (TI). Previous studies on TI have focused on the configuration of a circular torus and revealed the existence of a critical decay index of the overlying constraining magnetic field. Our study reveals that the critical index is a function of the fractional number of the partial torus, defined by the ratio between the arc length of the partial torus above the photosphere and the circumference of a circular torus of equal radius. We refer to this finding as the partial torus instability (PTI). It is found that a partial torus with a smaller fractional number has a smaller critical index, thus requiring a more gradually decreasing magnetic field to stabilize the flux rope. On the other hand, a partial torus with a larger fractional number has a larger critical index. In the limit of a circular torus when the fractional number approaches 1, the critical index goes to a maximum value. We demonstrate that the PTI helps us to understand the confinement, growth, and eventual eruption of a flux-rope CME.

Olmedo, Oscar; Zhang, Jie

2010-07-01

392

PARTIAL TORUS INSTABILITY  

SciTech Connect

Flux ropes are now generally accepted to be the magnetic configuration of coronal mass ejections (CMEs), which may be formed prior to or during solar eruptions. In this study, we model the flux rope as a current-carrying partial torus loop with its two footpoints anchored in the photosphere, and investigate its stability in the context of the torus instability (TI). Previous studies on TI have focused on the configuration of a circular torus and revealed the existence of a critical decay index of the overlying constraining magnetic field. Our study reveals that the critical index is a function of the fractional number of the partial torus, defined by the ratio between the arc length of the partial torus above the photosphere and the circumference of a circular torus of equal radius. We refer to this finding as the partial torus instability (PTI). It is found that a partial torus with a smaller fractional number has a smaller critical index, thus requiring a more gradually decreasing magnetic field to stabilize the flux rope. On the other hand, a partial torus with a larger fractional number has a larger critical index. In the limit of a circular torus when the fractional number approaches 1, the critical index goes to a maximum value. We demonstrate that the PTI helps us to understand the confinement, growth, and eventual eruption of a flux-rope CME.

Olmedo, Oscar; Zhang Jie, E-mail: oolmedo@gmu.ed [Department of Computational and Data Sciences, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States)

2010-07-20

393

Volume and density measurements for the IMGC Avogadro experiment  

Microsoft Academic Search

A critical review of the IMGC past measurements of the density of silicon crystals is presented. Problems of self-consistency among the density standards of IMGC seem to be caused by long-term shrinking of one of the Zerodur standards. A re-evaluation of these standards leads to new values of the density and of the molar volume of silicon.

Anna M. Peuto; Attilio Sacconi

1991-01-01

394

Anatomical and histological features of C-shaped canals in mandibular second molars.  

PubMed

The mandibular second molar has many root canal variations. This investigation used two evaluation methods to examine the canal morphology of mandibular second molars having C-shaped canals. Fifteen extracted mandibular second molars with a conical root and C-shaped canal orifice were separated into two groups. A polyester cast resin technique allowed three-dimensional visualization of the root canal system in eight teeth; the remaining seven molars were prepared for histological examination in cross-section in the coronal, middle, and apical thirds for study under the light microscope. The results illustrated that C-shaped canals in mandibular second molars can vary in number and shape along the length of the root with the result that debridement, obturation, and restoration in this group may be unusually difficult. PMID:1809802

Melton, D C; Krell, K V; Fuller, M W

1991-08-01

395

A New Anatomically Based Nomenclature for the Roots and Root Canals--Part 1: Maxillary Molars  

PubMed Central

Numerous terminologies have been employed in the dental literature to describe the roots and root canal systems of maxillary molars. This multiplicity in naming of roots and canals makes the reader susceptible to misinterpretation and confusion. No consensus thus far has been arrived at for defining the names of roots and root canals in maxillary molars, including their various morphological aberrations. The anatomical relation of roots and their root canals were identified and were subsequently named based on definite sets of criteria. A new method for identification and naming of roots and root canal anatomy in maxillary molars, based on their root and canal relationship, was formulated and is presented in this paper. The nomenclature makes certain essential modifications to the traditional approach to accommodate naming of the various aberrations presented in the maxillary molars. A simple, yet extensive, nomenclature system has been proposed that appropriately names the internal and external morphology of maxillary molars.

Kottoor, Jojo; Albuquerque, Denzil Valerian; Velmurugan, Natanasabapathy

2012-01-01

396

Growth hormone, prolactin and chorionic somatomammotropin in normal and molar pregnancy.  

PubMed

Twenty patients with molar pregnancy, ten normal pregnant women and ten healthy non-pregnant women were given 30 g of arginine intravenously. The serum concentration of growth hormone, prolactin and chorionic somatomammotropin (CS) was determined by radioimmunoassay. In addition, serum 17beta-estradiol, estriol and progesterone were also measured. Arginine infusion induced a sharp rise of GH in patients with molar pregnancy and in nonpregnant subjects, but the response in normal pregnancy was blunted. The response of PRL was high in patients with molar pregnancy, blunted in normal pregnancy and very small in nonpregnant subjects. CS did not respond at all to arginine infusion both in normal pregnancy and molar pregnancy. The high response to argine of PRL, normal response of GH and low baseline secretion and no response of CS may be characteristic of molar pregnancy. PMID:956347

Mochizuki, M; Morikawa, H; Kawaguchi, K; Tojo, S

1976-09-01

397

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

398

Root and canal morphology of permanent mandibular molars in a Sri Lankan population.  

PubMed

The main purpose of this study was to investigate the root and canal morphology of Sri Lankan mandibular molars and to determine the affinities of these morphological variations to those of people of European and Asian origin. Two hundred mandibular first and second molars were examined. The number of roots and the prevalence of C-shaped (gutter-shaped) roots in mandibular second molars were recorded. Root canal morphology was studied using a clearing technique. The examination of root canal systems of the teeth was based on Vertucci's classification. Among mandibular first molars, only 3% had three roots. Mesial roots of the first molar typically presented with two canals and two apical foramina with type IV, V, or VI canal configuration. Most distal roots of the first molar presented with a type I canal configuration. The remainder were distributed mainly between types III and V. Among mandibular second molars, 6% had single C-shaped roots, while C-shaped canals were found in only 2%. The majority of mesial roots of the second molar showed one or two canals, with one apical foramen with type I, II, or III canal morphology. In addition, the distal root commonly showed type I canal configuration. Intercanal communications and lateral canals were more frequently seen in the first molar than in the second. The root canal morphology in mandibular molars varies among population groups. Mandibular root and canal morphology of Sri Lankan people has closer affinities with that of people of European than of East Asian origin. PMID:17660977

Peiris, Roshan; Takahashi, Masami; Sasaki, Kayoko; Kanazawa, Eisaku

2007-07-25

399

Characterization of stem and progenitor cells in the dental pulp of erupted and unerupted murine molars  

PubMed Central

In the past few years there have been significant advances in the identification of putative stem cells also referred to as “mesenchymal stem cells” (MSC) in dental tissues including the dental pulp. It is thought that MSC in dental pulp share certain similarities with MSC isolated from other tissues. However, cells in dental pulp are still poorly characterized. This study focused on the characterization of progenitor and stem cells in dental pulps of erupted and unerupted mice molars. Our study showed that dental pulps from unerupted molars contain a significant number of cells expressing CD90+/CD45-, CD117+/CD45-, Sca-1+/CD45- and little if any CD45+ cells. Our in vitro functional studies showed that dental pulp cells from unerupted molars displayed extensive osteo-dentinogenic potential but were unable to differentiate into chondrocytes and adipocytes. Dental pulp from erupted molars displayed a reduced number of cells, contained higher percentage of CD45+ and lower percentage of cells expressing CD90+/CD45-, CD117+/CD45- as compared to unerupted molars. In vitro functional assays demonstrated the ability of a small fraction of cells to differentiate into odontoblasts, osteoblasts, adipocytes and chondrocytes. There was a significant reduction in the osteo-dentinogenic potential of the pulp cells derived from erupted molars compared to unerupted molars. Furthermore, the adipogenic and chondrogenic differentiation of pulp cells from erupted molars was dependent on a long induction period and infrequent. Based on these findings we propose that the dental pulp of the erupted molars contain a small population of multipotent cells, whereas the dental pulp of the unerupted molars does not contain multipotent cells but is enriched in osteo-dentinogenic progenitors engaged in the formation of coronal and radicular odontoblasts.

Balic, Anamaria; Aguila, H. Leonardo; Caimano, Melissa J.; Francone, Victor P.; Mina, Mina

2010-01-01

400

Pulpal responses to cavity preparation in aged rat molars.  

PubMed

The dentin-pulp complex is capable of repair after tooth injuries including dental procedures. However, few data are available concerning aged changes in pulpal reactions to such injuries. The present study aimed to clarify the capability of defense in aged pulp by investigating the responses of odontoblasts and cells positive for class II major histocompatibility complex (MHC) to cavity preparation in aged rat molars (300-360 days) and by comparing the results with those in young adult rats (100 days). In untreated control teeth, immunoreactivity for intense heat-shock protein (HSP)-25 and nestin was found in odontoblasts, whereas class-II-MHC-positive cells were densely distributed in the periphery of the pulp. Cavity preparation caused two types of pulpal reactions based on the different extent of damage in the aged rats. In the case of severe damage, destruction of the odontoblast layer was conspicuous at the affected site. By 12 h after cavity preparation, numerous class-II-MHC-positive cells appeared along the pulp-dentin border but subsequently disappeared together with HSP-25-immunopositive cells, and finally newly differentiated odontoblast-like cells took the place of the degenerated odontoblasts and acquired immunoreactivity for HSP-25 and nestin by postoperative day 3. In the case of mild damage, no remarkable changes occurred in odontoblasts after operation, and some survived through the experimental stages. These findings indicate that aged pulp tissue still possesses a defense capacity, and that a variety of reactions can occur depending on the difference in the status of dentinal tubules and/or odontoblast processes in individuals. PMID:16767403

Kawagishi, Eriko; Nakakura-Ohshima, Kuniko; Nomura, Shuichi; Ohshima, Hayato

2006-06-10

401

Root canal anatomy of mandibular second molars. Part I.  

PubMed

The root canal anatomy of 149 mandibular second molars was studied using a technique in which the pulp was removed, the canal space filled with black ink and the roots demineralized and made transparent. Of the 149 teeth, 22 per cent had single roots, 76 per cent had two roots and 2 per cent had three roots. In the single-rooted teeth, three canals were most common, while in the mesial root of the two-rooted teeth, two canals that joined near the apex and one canal in the distal root were most frequent. Round canals were most common in two-rooted teeth and C-shaped canals in single-rooted teeth. Transverse anastomoses were found in 33 per cent of roots, most commonly in the middle third of the root. Lateral canals were found in 72 per cent of roots, most commonly in the apical third of the root. The apical foramen was positioned at the apex in only 33 per cent of roots, and apical deltas were found in 35 per cent. The patient's age and race affected canal shape, with more round canals present in patients over 35 years of age, and more C-shaped canals in Asians. The sex of the patient and the side of the mouth affected the presence of apical deltas, with more being found in males and on the left side. Single-rooted teeth had more complex root canal systems than two-rooted teeth, with more lateral canals, transverse anastomoses, apical deltas and C-shaped canals. PMID:2391179

Manning, S A

1990-01-01

402

Root canals in one-rooted maxillary second molars.  

PubMed

The Royal Dental College, Copenhagen, houses an extensive collection of human teeth extracted in Denmark. The collection currently contains 104 one-rooted, permanent maxillary second molars. The root complex on these teeth was sectioned at the junction between the coronal and the apical halves, i.e. mid-root, and at the junction between the middle and the apical thirds, i.e. apically. Using a stereomicroscope we then registered, mid-root and apically, the following variables: canal number, canal position, and canal cross-section. Mid-root there was 1 centrally located root canal in 25.96% of the teeth examined; 2 canals were observed either mesially and distofacially, mesiofacially and distally, or facially and lingually in 34.62%; 3 canals positioned mesiofacially, distofacially, and lingually were found in 39.42%. At the same level 63.51% of the canal cross-sections were non-circular, whereas 36.49% of the canals had a circular cross-section image. The non-circular canal cross-sections could more specifically be characterized as C-shaped, Y-shaped, hourglass-shaped or the root canal had a greater faciolingual than mesiodistal extension or, respectively, a greater mesiodistal than faciolingual extension. Apically there was 1 centrally located root canal in 35.58%; 2 canals were observed with a position either mesially and distofacially, mesiofacially and distally, or facially and lingually in 37.49%; 3 canals located mesiofacially, distofacially, and lingually were found in 26.92%. At the apical level, 64.32% of the root canal cross-sections were non-circular, whereas 35.68% of the canals showed a circular cross-section. The results presented here are aimed at: clinical dentists, endodontists, and dental morphologists. PMID:1411268

Carlsen, O; Alexandersen, V; Heitmann, T; Jakobsen, P

1992-10-01

403

Alveolar bone loss and restorative dentistry in the primary molars.  

PubMed

This study examined the relationship between the status of the interproximal alveolar bone and the nature of the adjacent proximal surfaces in the primary molar area. In bite wing radiographs of 354 children, aged 6 to 9 years, 5091 sites were examined; 72.7% of the sites were adjacent to intact proximal surfaces, 14.2% to untreated proximal carious surfaces, and 13.0% to restored proximal surfaces. Marginal alveolar bone loss (ABL) was evident in 26.8% of the children, at 4.0% of the sites. Two thirds of the children with ABL had bone defects in more than 1 site. Males had a significantly higher mean number of sites affected with marginal ABL, per child, than females (mean = 2.4, SE = 0.2 and mean = 1.8, SE = 0.2 respectively). ABL was found adjacent to: 0.8% of the intact surfaces; 16.9% of the carious surfaces; 7.8% of the restored surfaces; 1.8% and 53.8% of the sites without or with proximal contact loss respectively; 3.8% and 30.8% of the sites with or without an adequate amalgam restoration respectively; 4.9% and 25.8% of the sites with an adequate or inadequate crown restoration respectively. The differences in distribution of marginal alveolar bone loss were highly significant (Chi square analysis, p = < 0.0001) for sites with intact, carious or restored sites, and for the presence or absence of contact loss, adequate amalgam or adequate crown. PMID:9161207

Bimstein, E; Zaidenberg, R; Soskolne, A W

1996-01-01

404

Partially coherent migration  

SciTech Connect

Partially coherent migration reduces the spurious details introduced by velocity macro-model imperfections. In a partially coherent migration, instead of summing coherently over the full aperture to achieve maximum lateral resolution, (1) a coherent stack is performed over a limited window width, and then (2) the collection of coherent stacks for different windows along the full aperture are summed incoherently to produce an amplitude value for each output point. Amplitude accuracy of a migration is improved with some sacrifice in spatial (lateral) resolution. A parameter in partially coherent migration is the running coherent window width, which accounts for the spatial correlation of errors in the velocity model. The coherent window width controls the trade-off between signal-to-noise ratio and lateral resolution. Assuming that timing errors introduced by imperfections of a velocity macro-model are from a zero-mean stationary Gaussian process, partially coherent migration is shown to raise the signal-to-noise ratio of the migrated image as compared to a conventional migration. The two competing aspects of signal-to-noise ratio and lateral resolution of the partially coherent migration in the presence of timing errors are analyzed in a stochastic framework. The intuitively attractive idea of limiting the coherent window width to the correlation length of the timing errors is confirmed numerically.

Lee, D. (Univ. of Pennsylvania, Philadelphia, PA (United States). Medical Image Processing Group, Dept. of Radiology); Jackson, G.M. (Elf Geoscience Research Centre, London (United Kingdom)); Mason, I.M. (Oxford Univ. (United Kingdom))

1993-09-01

405

Methanol partial oxidation reformer  

DOEpatents

A partial oxidation reformer 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.

Ahmed, Shabbir (Bolingbrook, IL); Kumar, Romesh (Naperville, IL); Krumpelt, Michael (Naperville, IL)

1999-01-01

406

Methanol partial oxidation reformer  

DOEpatents

A partial oxidation reformer 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.

Ahmed, Shabbir (Bolingbrook, IL); Kumar, Romesh (Naperville, IL); Krumpelt, Michael (Naperville, IL)

2001-01-01

407

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.

Dees, Dennis W. (Downers Grove, IL)

1994-01-01

408

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

409

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.

1999-08-24

410

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

411

Analysis of quantitative trait locus effects on the size and shape of mandibular molars in mice.  

PubMed Central

While >50 genes have been found to influence the development of teeth in mice, we still know very little about the genetic basis for the adaptive characteristics of teeth, such as size and shape. We applied interval mapping procedures to Procrustes size and shape data obtained from 10 morphological landmarks on the mandibular molar row of the F(2) progeny from a cross between the LG/J and SM/J strains of mice. This revealed many more QTL for molar shape (18) than for molar centroid size (3), although levels of dominance effects were comparable among QTL for size and shape. Comparisons of patterns of Procrustes additive and dominance shape effects and ordination of QTL effects by principal components analysis suggested that the effects of the shape QTL were dispersed among the three molars and thus that none of these molars represents a genetically distinct developmental structure. The results of an analysis of co-occurrence of QTL for molar shape, mandible shape, and cranial dimensions in these mice suggested that many of the QTL for molar shape may be the same as those affecting these other sets of characters, although in some cases this could be due to effects of closely linked genes.

Workman, Michael Scott; Leamy, Larry J; Routman, Eric J; Cheverud, James M

2002-01-01

412

Distal movement of mandibular molars in adult patients with the skeletal anchorage system.  

PubMed

The skeletal anchorage system (SAS) consists of titanium anchor plates and monocortical screws that are temporarily placed in either the maxilla or the mandible, or in both, as absolute orthodontic anchorage units. Distalization of the molars has been one of the most difficult biomechanical problems in traditional orthodontics, particularly in adults and in the mandible. However, it has now become possible to move molars distally with the SAS to correct anterior crossbites, maxillary dental protrusion, crowding, and dental asymmetries without having to extract premolars. This study evaluated the treatment and posttreatment changes during and after distalization of the mandibular molars. In 15 adult patients (12 women and 3 men), a total of 29 mandibular molars were successfully distalized with SAS. The amount of distalization and relapse and the type of tooth movement were analyzed with cephalometric radiographs and dental casts. The average amount of distalization of the mandibular first molars was 3.5 mm at the crown level and 1.8 mm at the root level. The average amount of relapse was 0.3 mm at both the crown and root apex levels. Of 29 mandibular molars, 9 were tipped back, and the others were translated distally in accordance with the established treatment goals. SAS is a viable modality to move mandibular molars for distally correcting anterior crossbites, malocclusions characterized by mandibular anterior crowding, and dental asymmetries. PMID:14765050

Sugawara, Junji; Daimaruya, Takayoshi; Umemori, Mikako; Nagasaka, Hiroshi; Takahashi, Ichiro; Kawamura, Hiroshi; Mitani, Hideo

2004-02-01

413

Plural partial associations  

NASA Astrophysics Data System (ADS)

The idea of the Plural Partial Associations is proposed to designate the case of associatability having the prototypes in ordinary life, but not described by the Associative Memory principle. The method based on computation of the correlation functions of the input vector with the back of the reference vectors is discussed as a one of the possible way to realize Plural Partial Associations and neural network model to implement this way is discussed. The possibility of this NN model implementation by two-layered bidirectional optical neural network used the Van der Lught correlator is discussed by the published before theoretical and experimental results.

Pavlov, Alexander V.

1996-12-01

414

Experimental partial epileptogenesis.  

PubMed

Identification of the responsible mutant genes and of the functional consequences of the mutations in experimental preparations have begun to shed light on mechanisms underlying a rare form of partial epilepsy in humans, autosomal dominant nocturnal frontal lobe epilepsy. Likewise, study of the mechanisms of nongenetic models of a common form of human epilepsy, complex partial epilepsy of temporal lobe origin, has established the hippocampal dentate granule cells as a functional barrier to invasion of epileptiform activity into hippocampus in normal brain; this barrier is defective in an epileptic brain. Potential mechanisms by which the 'barrier function' might become flawed, such as mossy fiber sprouting, are discussed. PMID:10226754

Bausch, S B; McNamara, J O

1999-04-01

415

Cholesterol-induced variations in the volume and enthalpy fluctuations of lipid bilayers.  

PubMed

The sound velocity and density of suspensions of large unilamellar liposomes from dimyristoylphosphatidylcholine with admixed cholesterol have been measured as a function of temperature around the chain melting temperature of the phospholipid. The cholesterol-to-phospholipid molar ratio xc has been varied over a wide range (0 partial volume of the phospholipid, and of the apparent specific adiabatic compressibility have been derived from the measured data. These data are particularly discussed with respect to the volume fluctuations within the samples. A theoretical relation between the compressibility and the excess heat capacity of the bilayer system has been derived. Comparison of the compressibilities (and sound velocity numbers) with heat capacity traces display the close correlation between these quantities for bilayer systems. This correlation appears to be very useful as it allows some of the mechanical properties of membrane systems to be calculated from the specific heat capacity data and vice versa. PMID:9649386

Halstenberg, S; Heimburg, T; Hianik, T; Kaatze, U; Krivanek, R

1998-07-01

416

Factors Affecting the Treatment Decisions and Outcome of Root-Resected Molars: A Nationwide Study.  

PubMed

Background: Treatment of furcation-involved molars represents a clinical challenge. This study retrospectively investigated the demographic parameters affecting the treatment decisions and outcome of root-resected molars by using a nationwide population-based dataset. Methods: A total of 471 eligible patients' de-identified data were obtained from a representative cohort composed of one million of Taiwan's population. Demographic factors which influence the treatment decisions and outcome of root-resected teeth were examined. Cox regression was performed to statistically analyze the factors. Results: The overall survival rates for root-resected molars were 91.1%. The survival times of the extracted and surviving teeth were 303.0 ± 274.6 and 551.8 ± 327.2 days, respectively (p<0.001). Of the analyzed subjects-related factors, such as living district, urbanization level, medical institutions, and monthly income have remarkable influence on treatment decisions; however, there is no statistically difference in survival rate between the root-resected molars receiving flap surgery or not (p=0.504). After adjusting for other factors, patients aged over 74 years have 3.33 times (hazard ratio=3.33; 95% CI=1.04-10.66; p=0.043) higher rate of molar extraction than younger counterparts. Conclusions: The overall survival rate of root-resected molars was satisfied, whereas subjects with advanced age > 74 years had a higher risk of extraction occurrence on resected molars. Subjects-related factors may influence the treatment decision on molars received flap surgery or not. These findings suggest that demographic factors should be carefully evaluated prior and after performing root resection procedure as these factors may eventually have impact on the outcome of root-resected molars. PMID:23327113

Yuh, Da-Yo; Cheng, Guo-Liang; Chien, Wu-Chien; Chung, Chi-Hsiang; Lin, Fu-Gong; Shieh, Yi-Shing; Fang, Wen-Hui; Mau, Lian-Ping; Fu, Earl; Huang, Ren-Yeong

2013-01-17

417

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

NASA Astrophysics Data System (ADS)

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 hydroxide. Results indicate that the analog task is a predictor of success on the molarity test; that difficulties encountered on the analog test are similar to those on the chemistry test, and that achievement on some types of chemistry problems might be improved by us in analog tasks in instruction.

Gabel, Dorothy L.; Samuel, K. V.

418

Removal of a Maxillary Third Molar Displaced into Pterygopalatine Fossa via Intraoral Approach  

PubMed Central

The removal of impacted maxillary third molars is one of the most common procedures performed in oral and maxillofacial surgery units with low rates of complications and morbidity. A few cases of accidental displacement of third molars into adjacent anatomical spaces, such as the infratemporal fossa, the pterygomandibular space, the maxillary sinus, buccal space, or the lateral pharyngeal space, during surgical interventions have been reported. In this paper, a case of a maxillary third molar accidentally displaced into the pterygopalatine fossa is presented, and the removal of the tooth via intraoral approach is described.

Ozer, Nedim; Ucem, Fulya; Saruhanoglu, Alp; Yilmaz, Serdar; Tanyeri, Hakk?

2013-01-01

419

[The appearance test of a molar tooth with phase shift shadow moiré].  

PubMed

Modern photo-mechanics testing techniques are widely used in industrial circles and academic circles. In order to solve the problem of biomedical engineering, shadow moiré method is used in oral and dental area in our study. A molar tooth was tested by phase shift shadow moiré method. Through testing molar tooth, the results show that shadow moiré method could be used for measuring the appearance of the oral area and concave and convex parts of molar tooth could also be distinguished and shown by interference patterns. The characteristics of shadow moirh are that it does't need exerting load on the specimen and could realize non-contact measurement. PMID:24059045

Mi, Honglin

2013-08-01

420

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.

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

2013-01-01

421

A New Anatomically Based Nomenclature for the Roots and Root Canals--Part 2: Mandibular Molars  

PubMed Central

Several terminologies have been employed in the dental literature to describe the roots and root canal systems of mandibular molars with no consensus being arrived at, thus far. The anatomical relation of roots and their root canals were identified and a naming system was formulated. The proposed nomenclature attempts to make certain essential modifications to the traditional approach to accommodate the naming of various aberrations presented in mandibular molars. A simple, yet extensive nomenclature system has been proposed that appropriately names the internal and external morphology of mandibular molars.

Valerian Albuquerque, Denzil; Kottoor, Jojo; Velmurugan, Natanasabapathy

2012-01-01

422

Evaluation of maxillary molar distalization with the distal jet: a comparison with other contemporary methods.  

PubMed

Maxillary molar distalization is an increasingly popular option for the resolution of Class II malocclusions. This communication describes the effects of one particular molar distalizing appliance, the distal jet, in a sample of 20 consecutively treated and growing subjects (11 females, nine males; mean starting age of 13) and compares these effects with those of similar devices. Pre- and postdistalization cephalometric radiographs and dental models were analyzed to determine the dental and skeletal effects. The distal jet appliances were constructed using a biomechanical couple to direct the distalizing force to the level of the maxillary first molar's center of resistance. The distal jet was the only appliance used during the distalization phase of treatment. Examination of the cephalometric tracings demonstrated that the crowns of the maxillary first molars were distalized an average of 3.2 mm into a Class I molar relationship. In the process, the first molars were tipped distally an average of 3.1 degrees, however, the amount of tipping in each case was influenced by the state of eruption of the second molar. In subjects whose second molars had erupted only to the level of the apical third of the first molar roots, distal tipping was almost twice that seen when the second molar had completed their eruption. Anchorage loss measured at the first premolars averaged 1.3 mm, but the crowns tipped 3.1 degrees distally because of the design of the appliance. The maxillary incisors were proclined an average of 0.6 degrees with minimal effect on the mandibular plane angle and lower facial height. This study suggests that the distal jet appliance effectively moves the maxillary molars distally into a Class I molar relationship with minimal distal tipping, however, some loss of anchorage is to be expected during this process. The distal jet appliance compares favorably with other intraoral distalization devices and with mechanics featuring mandibular protraction for the resolution of patients with Class II, despite the fact that these types of mechanics address different jaws. PMID:12401059

Bolla, Eugenio; Muratore, Filippo; Carano, Aldo; Bowman, S Jay

2002-10-01

423

The effectiveness of a single osteointegrated implant combined with pendulum springs for molar distalization.  

PubMed

The aim of this report was to present the clinical efficiency of a single osteointegrated implant combined with pendulum springs for molar distalization. A 15-year-old girl sought treatment for irregular anterior teeth and poor smile esthetics. A novel appliance was designed that combined osteointegrated implants with 0.032-in beta-titanium wire and pendulum springs. The treatment results were evaluated from lateral cephalometric radiographs. Distalization of the maxillary first molars was achieved in 6 months. Total treatment time was 21 months. Facial esthetics improved as a consequence of treatment. This appliance design offers reliable molar distalization, even when absolute anchorage is required. PMID:17276871

Onca?, Gökhan; Akyalçin, Sercan; Arikan, Fatih

2007-02-01

424

Standard molar enthalpies of formation of some trichloroanilines by rotating-bomb calorimetry  

Microsoft Academic Search

The standard ( po= 0.1 MPa) molar enthalpies of formation ?fHmo, at the temperature 298.15 K, for crystalline 2,3,4-, 2,4,5-, 2,4,6- and 3,4,5-trichloroaniline were derived from the molar enthalpies of combustion ?cHmoin oxygen using rotating bomb combustion calorimetry. The reaction products were CO2(g), N2(g), and HCl · 600H2O(l). The standard molar enthalpies of sublimation ?crgHmoat T= 298.15 K were measured

Ana I. M. C. L. Ferreira

2002-01-01

425

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

426

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.

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

2013-01-01

427

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

428

Reviving Partial Order Planning  

Microsoft Academic Search

This paper challenges the prevailing pessimism about the scalability of partial order planning (POP) algorithms by presenting several novel heuristic control techniques that make them competitive with the state of the art plan syn- thesis algorithms. Our key insight is that the techniques responsible for the efficiency of the currently success- ful planners-viz., distance based heuristics, reachability analysis and disjunctive

Xuanlong Nguyen; Subbarao Kambhampati

2001-01-01

429

Partial observability and learnability  

Microsoft Academic Search

When sensing its environment, an agent often receives information that only partially describes the current state of affairs. The agent then attempts to predict what it has not sensed, by using other pieces of information available through its sensors. Machine learning techniques can naturally aid this task, by providing the agent with the rules to be used for making these

Loizos Michael

2010-01-01

430

Partial trisomy 3q  

Microsoft Academic Search

A new case of partial trisomy 3q is reported in a 5-year-old female with severe congenital malformations and psychomotor retardation. A review of the literature, with a total of 11 patients, allows us to conclude that the clinical picture reminiscent of the Cornelia de Lange syndrome is caused by the trisomic state.

E. Yunis; L. Quintero; A. Castefieda; E. Ramirez; M. Leibovici

1979-01-01

431

Partial Dead Code Elimination  

Microsoft Academic Search

A new aggressive algorithm for the elimination of par- tially dead code is presented, i.e., of code which is only dead on some program paths. Besides being more pow- erful than the usual approaches to dead code elimina- tion, this algorithm is optimal in the following sense: partially dead code remaining in the resulting program cannot be eliminated without changing

Jens Knoop; Oliver Rüthing; Bernhard Steffen

1994-01-01

432

Partial oxidation system  

Microsoft Academic Search

A partial oxidation control system for continuously producing synthesis gas, fuel gas or reducing gas in which one process fuel is replaced by a different fuel without shutting down or depressurizing the gas generator. Suitable burners for introducing the feedstreams into the gas generator comprise a central conduit means radially spaced from a concentric coaxial outer conduit having a downstream

C. P. Marion; A. Brent; E. T. Child; W. B. Crouch; B. Reynolds; G. N. Richter

1984-01-01

433

Sonic Partial Deduction  

Microsoft Academic Search

The current state of the art for ensuring finite unfolding of logic programs consists of a number of online techniques where unfolding decisions are made at specialisation time. Introduction of a static termination analysis phase into a partial deduction algorithm permits unfolding decisions to be made oine, before the actual specialisation phase itself. This separation improves specialisation time and facilitates

Jonathan C. Martin; Michael Leuschel

1999-01-01

434

Partial quantum information.  

PubMed

Information--be it classical or quantum--is measured by the amount of communication needed to convey it. In the classical case, if the receiver has some prior information about the messages being conveyed, less communication is needed. Here we explore the concept of prior quantum information: given an unknown quantum state distributed over two systems, we determine how much quantum communication is needed to transfer the full state to one system. This communication measures the partial information one system needs, conditioned on its prior information. We find that it is given by the conditional entropy--a quantity that was known previously, but lacked an operational meaning. In the classical case, partial information must always be positive, but we find that in the quantum world this physical quantity can be negative. If the partial information is positive, its sender needs to communicate this number of quantum bits to the receiver; if it is negative, then sender and receiver instead gain the corresponding potential for future quantum communication. We introduce a protocol that we term 'quantum state merging' which optimally transfers partial information. We show how it enables a systematic understanding of quantum network theory, and discuss several important applications including distributed compression, noiseless coding with side information, multiple access channels and assisted entanglement distillation. PMID:16079840

Horodecki, Micha?; Oppenheim, Jonathan; Winter, Andreas

2005-08-01

435

Generalized Partial Indexes  

Microsoft Academic Search

This paper demonstrates the use of generalized par- tial indexes for efficient query processing. We propose that partial indexes be built on those portions of the database that are statistically likely to be the most useful for query processing. We identify three classes of statistical infor- mation, and two levels at which it may be available. We describe indexing strategies

Praveen Seshadri; Arun N. Swami

1995-01-01

436

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

Microsoft Academic Search

Among primates, age at first molar emergence is correlated with a variety of life history traits. Age at first molar emergence can therefore be used to broadly infer 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

Jay Kelley; Tanya M. Smith

2003-01-01

437

The Determination of Partial Moments  

Microsoft Academic Search

In statistical decision theory, computations often involve the partial moments of a random variable. Several methods for determining partial moments are discussed, including direct calculation, the use of general formulas which apply to entire families of distributions, and the use of partial moment generating functions. Using these methods, formulas (some involving recursive relationships) are developed for the partial moments of

Robert L. Winkler; Gary M. Roodman; Robert R. Britney

1972-01-01

438

Endodontic Treatment of a Mandibular Second Molar with Two Mesial Roots: Report of a Case  

PubMed Central

A case of unusual root morphology is presented to demonstrate anatomic variations in mandibular second molars. The most common configuration of mandibular second molar is to have two roots with three root canals; however mandibular molars may have many different combinations. Endodontic therapy was performed in a mandibular second molar with 3 separate roots 2 located mesially and one distally. Radiographically all 3 root canals terminated with individual foramina. Three orifices or 3 independent canals were found in the 3 separate roots, indicating a rare anatomic configuration. Looking for additional roots, canals and unusual morphology is an important part of successful endodontics as the knowledge of their existence occasionally enable clinicians to treat a case that otherwise might have ended in failure.

Ravanshad, Shohreh; Nabavizade, Mohammad Reza

2008-01-01

439

Endodontic Management of Mandibular First Molar with Middle Distal Canal: A Case Report  

PubMed Central

The knowledge of variations in root canal morphology is critical for a successful endodontic treatment. This article presents the endodontic management of a unique case of mandibular molar with middle distal canal which is quite uncommon.

Venumuddala, Vijay Reddy; Sridhar, M.; Rajasekaran, M.; Poorni, Saravanan; Senthilkumaran, Gnanaprakasam

2012-01-01

440

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

PubMed Central

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 was placed and immediately loaded to distalize the left upper first and second molar. The average distalization time to achieve an overcorrected Class I molar relationship was 3.6 months. There was no change in overjet, overbite, or mandibular plane angle measurements. Mild protrusion (0.5 mm) of the upper left central incisor was also r